Squashed 'vendor/github.com/miekg/dns/' content from commit 5c01f20

git-subtree-dir: vendor/github.com/miekg/dns
git-subtree-split: 5c01f20c3a

.gitignore

@@ -0,0 +1,4 @@
+*.6
+tags
+test.out
+a.out

.travis.yml

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+language: go
+sudo: false
+go:
+  - 1.4
+  - 1.5
+script:
+  - go test -race -v -bench=.

AUTHORS

@@ -0,0 +1 @@
+Miek Gieben <miek@miek.nl>

CONTRIBUTORS

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+Alex A. Skinner
+Andrew Tunnell-Jones
+Ask Bjørn Hansen
+Dave Cheney
+Dusty Wilson
+Marek Majkowski
+Peter van Dijk
+Omri Bahumi
+Alex Sergeyev

COPYRIGHT

@@ -0,0 +1,9 @@
+Copyright 2009 The Go Authors. All rights reserved. Use of this source code
+is governed by a BSD-style license that can be found in the LICENSE file.
+Extensions of the original work are copyright (c) 2011 Miek Gieben
+
+Copyright 2011 Miek Gieben. All rights reserved. Use of this source code is
+governed by a BSD-style license that can be found in the LICENSE file.
+
+Copyright 2014 CloudFlare. All rights reserved. Use of this source code is
+governed by a BSD-style license that can be found in the LICENSE file.

LICENSE

@@ -0,0 +1,32 @@
+Extensions of the original work are copyright (c) 2011 Miek Gieben
+
+As this is fork of the official Go code the same license applies:
+
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+

README.md

@@ -0,0 +1,155 @@
+[![Build Status](https://travis-ci.org/miekg/dns.svg?branch=master)](https://travis-ci.org/miekg/dns)
+
+# Alternative (more granular) approach to a DNS library
+
+> Less is more.
+
+Complete and usable DNS library. All widely used Resource Records are
+supported, including the DNSSEC types. It follows a lean and mean philosophy.
+If there is stuff you should know as a DNS programmer there isn't a convenience
+function for it. Server side and client side programming is supported, i.e. you
+can build servers and resolvers with it.
+
+We try to keep the "master" branch as sane as possible and at the bleeding edge
+of standards, avoiding breaking changes wherever reasonable. We support the last
+two versions of Go, currently: 1.4 and 1.5.
+
+# Goals
+
+* KISS;
+* Fast;
+* Small API, if its easy to code in Go, don't make a function for it.
+
+# Users
+
+A not-so-up-to-date-list-that-may-be-actually-current:
+
+* https://cloudflare.com
+* https://github.com/abh/geodns
+* http://www.statdns.com/
+* http://www.dnsinspect.com/
+* https://github.com/chuangbo/jianbing-dictionary-dns
+* http://www.dns-lg.com/
+* https://github.com/fcambus/rrda
+* https://github.com/kenshinx/godns
+* https://github.com/skynetservices/skydns
+* https://github.com/DevelopersPL/godnsagent
+* https://github.com/duedil-ltd/discodns
+* https://github.com/StalkR/dns-reverse-proxy
+* https://github.com/tianon/rawdns
+* https://mesosphere.github.io/mesos-dns/
+* https://pulse.turbobytes.com/
+* https://play.google.com/store/apps/details?id=com.turbobytes.dig
+* https://github.com/fcambus/statzone
+* https://github.com/benschw/dns-clb-go
+* https://github.com/corny/dnscheck for http://public-dns.tk/
+* https://namesmith.io
+* https://github.com/miekg/unbound
+* https://github.com/miekg/exdns
+
+Send pull request if you want to be listed here.
+
+# Features
+
+* UDP/TCP queries, IPv4 and IPv6;
+* RFC 1035 zone file parsing ($INCLUDE, $ORIGIN, $TTL and $GENERATE (for all record types) are supported;
+* Fast:
+    * Reply speed around ~ 80K qps (faster hardware results in more qps);
+    * Parsing RRs ~ 100K RR/s, that's 5M records in about 50 seconds;
+* Server side programming (mimicking the net/http package);
+* Client side programming;
+* DNSSEC: signing, validating and key generation for DSA, RSA and ECDSA;
+* EDNS0, NSID;
+* AXFR/IXFR;
+* TSIG, SIG(0);
+* DNS over TLS: optional encrypted connection between client and server;
+* DNS name compression;
+* Depends only on the standard library.
+
+Have fun!
+
+Miek Gieben  -  2010-2012  -  <miek@miek.nl>
+
+# Building
+
+Building is done with the `go` tool. If you have setup your GOPATH
+correctly, the following should work:
+
+    go get github.com/miekg/dns
+    go build github.com/miekg/dns
+
+## Examples
+
+A short "how to use the API" is at the beginning of doc.go (this also will show
+when you call `godoc github.com/miekg/dns`).
+
+Example programs can be found in the `github.com/miekg/exdns` repository.
+
+## Supported RFCs
+
+*all of them*
+
+* 103{4,5} - DNS standard
+* 1348 - NSAP record (removed the record)
+* 1982 - Serial Arithmetic
+* 1876 - LOC record
+* 1995 - IXFR
+* 1996 - DNS notify
+* 2136 - DNS Update (dynamic updates)
+* 2181 - RRset definition - there is no RRset type though, just []RR
+* 2537 - RSAMD5 DNS keys
+* 2065 - DNSSEC (updated in later RFCs)
+* 2671 - EDNS record
+* 2782 - SRV record
+* 2845 - TSIG record
+* 2915 - NAPTR record
+* 2929 - DNS IANA Considerations
+* 3110 - RSASHA1 DNS keys
+* 3225 - DO bit (DNSSEC OK)
+* 340{1,2,3} - NAPTR record
+* 3445 - Limiting the scope of (DNS)KEY
+* 3597 - Unknown RRs
+* 4025 - IPSECKEY
+* 403{3,4,5} - DNSSEC + validation functions
+* 4255 - SSHFP record
+* 4343 - Case insensitivity
+* 4408 - SPF record
+* 4509 - SHA256 Hash in DS
+* 4592 - Wildcards in the DNS
+* 4635 - HMAC SHA TSIG
+* 4701 - DHCID
+* 4892 - id.server
+* 5001 - NSID
+* 5155 - NSEC3 record
+* 5205 - HIP record
+* 5702 - SHA2 in the DNS
+* 5936 - AXFR
+* 5966 - TCP implementation recommendations
+* 6605 - ECDSA
+* 6725 - IANA Registry Update
+* 6742 - ILNP DNS
+* 6840 - Clarifications and Implementation Notes for DNS Security
+* 6844 - CAA record
+* 6891 - EDNS0 update
+* 6895 - DNS IANA considerations
+* 6975 - Algorithm Understanding in DNSSEC
+* 7043 - EUI48/EUI64 records
+* 7314 - DNS (EDNS) EXPIRE Option
+* 7553 - URI record
+* xxxx - EDNS0 DNS Update Lease (draft)
+* yyyy - DNS over TLS: Initiation and Performance Considerations (draft)
+
+## Loosely based upon
+
+* `ldns`
+* `NSD`
+* `Net::DNS`
+* `GRONG`
+
+## TODO
+
+* privatekey.Precompute() when signing?
+* Last remaining RRs: APL, ATMA, A6, NSAP and NXT.
+* Missing in parsing: ISDN, UNSPEC, NSAP and ATMA.
+* NSEC(3) cover/match/closest enclose.
+* Replies with TC bit are not parsed to the end.

client.go

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+package dns
+
+// A client implementation.
+
+import (
+	"bytes"
+	"crypto/tls"
+	"io"
+	"net"
+	"time"
+)
+
+const dnsTimeout time.Duration = 2 * time.Second
+const tcpIdleTimeout time.Duration = 8 * time.Second
+
+// A Conn represents a connection to a DNS server.
+type Conn struct {
+	net.Conn                         // a net.Conn holding the connection
+	UDPSize        uint16            // minimum receive buffer for UDP messages
+	TsigSecret     map[string]string // secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be fully qualified
+	rtt            time.Duration
+	t              time.Time
+	tsigRequestMAC string
+}
+
+// A Client defines parameters for a DNS client.
+type Client struct {
+	Net            string            // if "tcp" or "tcp-tls" (DNS over TLS) a TCP query will be initiated, otherwise an UDP one (default is "" for UDP)
+	UDPSize        uint16            // minimum receive buffer for UDP messages
+	TLSConfig      *tls.Config       // TLS connection configuration
+	DialTimeout    time.Duration     // net.DialTimeout, defaults to 2 seconds
+	ReadTimeout    time.Duration     // net.Conn.SetReadTimeout value for connections, defaults to 2 seconds
+	WriteTimeout   time.Duration     // net.Conn.SetWriteTimeout value for connections, defaults to 2 seconds
+	TsigSecret     map[string]string // secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be fully qualified
+	SingleInflight bool              // if true suppress multiple outstanding queries for the same Qname, Qtype and Qclass
+	group          singleflight
+}
+
+// Exchange performs a synchronous UDP query. It sends the message m to the address
+// contained in a and waits for an reply. Exchange does not retry a failed query, nor
+// will it fall back to TCP in case of truncation.
+// If you need to send a DNS message on an already existing connection, you can use the
+// following:
+//
+//	co := &dns.Conn{Conn: c} // c is your net.Conn
+//	co.WriteMsg(m)
+//	in, err := co.ReadMsg()
+//	co.Close()
+//
+func Exchange(m *Msg, a string) (r *Msg, err error) {
+	var co *Conn
+	co, err = DialTimeout("udp", a, dnsTimeout)
+	if err != nil {
+		return nil, err
+	}
+
+	defer co.Close()
+
+	opt := m.IsEdns0()
+	// If EDNS0 is used use that for size.
+	if opt != nil && opt.UDPSize() >= MinMsgSize {
+		co.UDPSize = opt.UDPSize()
+	}
+
+	co.SetWriteDeadline(time.Now().Add(dnsTimeout))
+	if err = co.WriteMsg(m); err != nil {
+		return nil, err
+	}
+
+	co.SetReadDeadline(time.Now().Add(dnsTimeout))
+	r, err = co.ReadMsg()
+	if err == nil && r.Id != m.Id {
+		err = ErrId
+	}
+	return r, err
+}
+
+// ExchangeConn performs a synchronous query. It sends the message m via the connection
+// c and waits for a reply. The connection c is not closed by ExchangeConn.
+// This function is going away, but can easily be mimicked:
+//
+//	co := &dns.Conn{Conn: c} // c is your net.Conn
+//	co.WriteMsg(m)
+//	in, _  := co.ReadMsg()
+//	co.Close()
+//
+func ExchangeConn(c net.Conn, m *Msg) (r *Msg, err error) {
+	println("dns: this function is deprecated")
+	co := new(Conn)
+	co.Conn = c
+	if err = co.WriteMsg(m); err != nil {
+		return nil, err
+	}
+	r, err = co.ReadMsg()
+	if err == nil && r.Id != m.Id {
+		err = ErrId
+	}
+	return r, err
+}
+
+// Exchange performs an synchronous query. It sends the message m to the address
+// contained in a and waits for an reply. Basic use pattern with a *dns.Client:
+//
+//	c := new(dns.Client)
+//	in, rtt, err := c.Exchange(message, "127.0.0.1:53")
+//
+// Exchange does not retry a failed query, nor will it fall back to TCP in
+// case of truncation.
+func (c *Client) Exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err error) {
+	if !c.SingleInflight {
+		return c.exchange(m, a)
+	}
+	// This adds a bunch of garbage, TODO(miek).
+	t := "nop"
+	if t1, ok := TypeToString[m.Question[0].Qtype]; ok {
+		t = t1
+	}
+	cl := "nop"
+	if cl1, ok := ClassToString[m.Question[0].Qclass]; ok {
+		cl = cl1
+	}
+	r, rtt, err, shared := c.group.Do(m.Question[0].Name+t+cl, func() (*Msg, time.Duration, error) {
+		return c.exchange(m, a)
+	})
+	if err != nil {
+		return r, rtt, err
+	}
+	if shared {
+		return r.Copy(), rtt, nil
+	}
+	return r, rtt, nil
+}
+
+func (c *Client) dialTimeout() time.Duration {
+	if c.DialTimeout != 0 {
+		return c.DialTimeout
+	}
+	return dnsTimeout
+}
+
+func (c *Client) readTimeout() time.Duration {
+	if c.ReadTimeout != 0 {
+		return c.ReadTimeout
+	}
+	return dnsTimeout
+}
+
+func (c *Client) writeTimeout() time.Duration {
+	if c.WriteTimeout != 0 {
+		return c.WriteTimeout
+	}
+	return dnsTimeout
+}
+
+func (c *Client) exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err error) {
+	var co *Conn
+	network := "udp"
+	tls := false
+
+	switch c.Net {
+	case "tcp-tls":
+		network = "tcp"
+		tls = true
+	case "tcp4-tls":
+		network = "tcp4"
+		tls = true
+	case "tcp6-tls":
+		network = "tcp6"
+		tls = true
+	default:
+		if c.Net != "" {
+			network = c.Net
+		}
+	}
+
+	if tls {
+		co, err = DialTimeoutWithTLS(network, a, c.TLSConfig, c.dialTimeout())
+	} else {
+		co, err = DialTimeout(network, a, c.dialTimeout())
+	}
+
+	if err != nil {
+		return nil, 0, err
+	}
+	defer co.Close()
+
+	opt := m.IsEdns0()
+	// If EDNS0 is used use that for size.
+	if opt != nil && opt.UDPSize() >= MinMsgSize {
+		co.UDPSize = opt.UDPSize()
+	}
+	// Otherwise use the client's configured UDP size.
+	if opt == nil && c.UDPSize >= MinMsgSize {
+		co.UDPSize = c.UDPSize
+	}
+
+	co.TsigSecret = c.TsigSecret
+	co.SetWriteDeadline(time.Now().Add(c.writeTimeout()))
+	if err = co.WriteMsg(m); err != nil {
+		return nil, 0, err
+	}
+
+	co.SetReadDeadline(time.Now().Add(c.readTimeout()))
+	r, err = co.ReadMsg()
+	if err == nil && r.Id != m.Id {
+		err = ErrId
+	}
+	return r, co.rtt, err
+}
+
+// ReadMsg reads a message from the connection co.
+// If the received message contains a TSIG record the transaction
+// signature is verified.
+func (co *Conn) ReadMsg() (*Msg, error) {
+	p, err := co.ReadMsgHeader(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	m := new(Msg)
+	if err := m.Unpack(p); err != nil {
+		// If ErrTruncated was returned, we still want to allow the user to use
+		// the message, but naively they can just check err if they don't want
+		// to use a truncated message
+		if err == ErrTruncated {
+			return m, err
+		}
+		return nil, err
+	}
+	if t := m.IsTsig(); t != nil {
+		if _, ok := co.TsigSecret[t.Hdr.Name]; !ok {
+			return m, ErrSecret
+		}
+		// Need to work on the original message p, as that was used to calculate the tsig.
+		err = TsigVerify(p, co.TsigSecret[t.Hdr.Name], co.tsigRequestMAC, false)
+	}
+	return m, err
+}
+
+// ReadMsgHeader reads a DNS message, parses and populates hdr (when hdr is not nil).
+// Returns message as a byte slice to be parsed with Msg.Unpack later on.
+// Note that error handling on the message body is not possible as only the header is parsed.
+func (co *Conn) ReadMsgHeader(hdr *Header) ([]byte, error) {
+	var (
+		p   []byte
+		n   int
+		err error
+	)
+
+	switch t := co.Conn.(type) {
+	case *net.TCPConn, *tls.Conn:
+		r := t.(io.Reader)
+
+		// First two bytes specify the length of the entire message.
+		l, err := tcpMsgLen(r)
+		if err != nil {
+			return nil, err
+		}
+		p = make([]byte, l)
+		n, err = tcpRead(r, p)
+
+	default:
+		if co.UDPSize > MinMsgSize {
+			p = make([]byte, co.UDPSize)
+		} else {
+			p = make([]byte, MinMsgSize)
+		}
+		n, err = co.Read(p)
+	}
+
+	if err != nil {
+		return nil, err
+	} else if n < headerSize {
+		return nil, ErrShortRead
+	}
+
+	p = p[:n]
+	if hdr != nil {
+		if _, err = UnpackStruct(hdr, p, 0); err != nil {
+			return nil, err
+		}
+	}
+	return p, err
+}
+
+// tcpMsgLen is a helper func to read first two bytes of stream as uint16 packet length.
+func tcpMsgLen(t io.Reader) (int, error) {
+	p := []byte{0, 0}
+	n, err := t.Read(p)
+	if err != nil {
+		return 0, err
+	}
+	if n != 2 {
+		return 0, ErrShortRead
+	}
+	l, _ := unpackUint16(p, 0)
+	if l == 0 {
+		return 0, ErrShortRead
+	}
+	return int(l), nil
+}
+
+// tcpRead calls TCPConn.Read enough times to fill allocated buffer.
+func tcpRead(t io.Reader, p []byte) (int, error) {
+	n, err := t.Read(p)
+	if err != nil {
+		return n, err
+	}
+	for n < len(p) {
+		j, err := t.Read(p[n:])
+		if err != nil {
+			return n, err
+		}
+		n += j
+	}
+	return n, err
+}
+
+// Read implements the net.Conn read method.
+func (co *Conn) Read(p []byte) (n int, err error) {
+	if co.Conn == nil {
+		return 0, ErrConnEmpty
+	}
+	if len(p) < 2 {
+		return 0, io.ErrShortBuffer
+	}
+	switch t := co.Conn.(type) {
+	case *net.TCPConn, *tls.Conn:
+		r := t.(io.Reader)
+
+		l, err := tcpMsgLen(r)
+		if err != nil {
+			return 0, err
+		}
+		if l > len(p) {
+			return int(l), io.ErrShortBuffer
+		}
+		return tcpRead(r, p[:l])
+	}
+	// UDP connection
+	n, err = co.Conn.Read(p)
+	if err != nil {
+		return n, err
+	}
+
+	co.rtt = time.Since(co.t)
+	return n, err
+}
+
+// WriteMsg sends a message through the connection co.
+// If the message m contains a TSIG record the transaction
+// signature is calculated.
+func (co *Conn) WriteMsg(m *Msg) (err error) {
+	var out []byte
+	if t := m.IsTsig(); t != nil {
+		mac := ""
+		if _, ok := co.TsigSecret[t.Hdr.Name]; !ok {
+			return ErrSecret
+		}
+		out, mac, err = TsigGenerate(m, co.TsigSecret[t.Hdr.Name], co.tsigRequestMAC, false)
+		// Set for the next read, although only used in zone transfers
+		co.tsigRequestMAC = mac
+	} else {
+		out, err = m.Pack()
+	}
+	if err != nil {
+		return err
+	}
+	co.t = time.Now()
+	if _, err = co.Write(out); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Write implements the net.Conn Write method.
+func (co *Conn) Write(p []byte) (n int, err error) {
+	switch t := co.Conn.(type) {
+	case *net.TCPConn, *tls.Conn:
+		w := t.(io.Writer)
+
+		lp := len(p)
+		if lp < 2 {
+			return 0, io.ErrShortBuffer
+		}
+		if lp > MaxMsgSize {
+			return 0, &Error{err: "message too large"}
+		}
+		l := make([]byte, 2, lp+2)
+		l[0], l[1] = packUint16(uint16(lp))
+		p = append(l, p...)
+		n, err := io.Copy(w, bytes.NewReader(p))
+		return int(n), err
+	}
+	n, err = co.Conn.(*net.UDPConn).Write(p)
+	return n, err
+}
+
+// Dial connects to the address on the named network.
+func Dial(network, address string) (conn *Conn, err error) {
+	conn = new(Conn)
+	conn.Conn, err = net.Dial(network, address)
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}
+
+// DialTimeout acts like Dial but takes a timeout.
+func DialTimeout(network, address string, timeout time.Duration) (conn *Conn, err error) {
+	conn = new(Conn)
+	conn.Conn, err = net.DialTimeout(network, address, timeout)
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}
+
+// DialWithTLS connects to the address on the named network with TLS.
+func DialWithTLS(network, address string, tlsConfig *tls.Config) (conn *Conn, err error) {
+	conn = new(Conn)
+	conn.Conn, err = tls.Dial(network, address, tlsConfig)
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}
+
+// DialTimeoutWithTLS acts like DialWithTLS but takes a timeout.
+func DialTimeoutWithTLS(network, address string, tlsConfig *tls.Config, timeout time.Duration) (conn *Conn, err error) {
+	var dialer net.Dialer
+	dialer.Timeout = timeout
+
+	conn = new(Conn)
+	conn.Conn, err = tls.DialWithDialer(&dialer, network, address, tlsConfig)
+	if err != nil {
+		return nil, err
+	}
+	return conn, nil
+}

client_test.go

@@ -0,0 +1,421 @@
+package dns
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net"
+	"strconv"
+	"testing"
+	"time"
+)
+
+func TestClientSync(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServer)
+	defer HandleRemove("miek.nl.")
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeSOA)
+
+	c := new(Client)
+	r, _, err := c.Exchange(m, addrstr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	if r != nil && r.Rcode != RcodeSuccess {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+	// And now with plain Exchange().
+	r, err = Exchange(m, addrstr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	if r == nil || r.Rcode != RcodeSuccess {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+}
+
+func TestClientTLSSync(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServer)
+	defer HandleRemove("miek.nl.")
+
+	cert, err := tls.X509KeyPair(CertPEMBlock, KeyPEMBlock)
+	if err != nil {
+		t.Fatalf("unable to build certificate: %v", err)
+	}
+
+	config := tls.Config{
+		Certificates: []tls.Certificate{cert},
+	}
+
+	s, addrstr, err := RunLocalTLSServer("127.0.0.1:0", &config)
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeSOA)
+
+	c := new(Client)
+	c.Net = "tcp-tls"
+	c.TLSConfig = &tls.Config{
+		InsecureSkipVerify: true,
+	}
+
+	r, _, err := c.Exchange(m, addrstr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	if r != nil && r.Rcode != RcodeSuccess {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+}
+
+func TestClientSyncBadId(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServerBadId)
+	defer HandleRemove("miek.nl.")
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeSOA)
+
+	c := new(Client)
+	if _, _, err := c.Exchange(m, addrstr); err != ErrId {
+		t.Errorf("did not find a bad Id")
+	}
+	// And now with plain Exchange().
+	if _, err := Exchange(m, addrstr); err != ErrId {
+		t.Errorf("did not find a bad Id")
+	}
+}
+
+func TestClientEDNS0(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServer)
+	defer HandleRemove("miek.nl.")
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeDNSKEY)
+
+	m.SetEdns0(2048, true)
+
+	c := new(Client)
+	r, _, err := c.Exchange(m, addrstr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+
+	if r != nil && r.Rcode != RcodeSuccess {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+}
+
+// Validates the transmission and parsing of local EDNS0 options.
+func TestClientEDNS0Local(t *testing.T) {
+	optStr1 := "1979:0x0707"
+	optStr2 := strconv.Itoa(EDNS0LOCALSTART) + ":0x0601"
+
+	handler := func(w ResponseWriter, req *Msg) {
+		m := new(Msg)
+		m.SetReply(req)
+
+		m.Extra = make([]RR, 1, 2)
+		m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello local edns"}}
+
+		// If the local options are what we expect, then reflect them back.
+		ec1 := req.Extra[0].(*OPT).Option[0].(*EDNS0_LOCAL).String()
+		ec2 := req.Extra[0].(*OPT).Option[1].(*EDNS0_LOCAL).String()
+		if ec1 == optStr1 && ec2 == optStr2 {
+			m.Extra = append(m.Extra, req.Extra[0])
+		}
+
+		w.WriteMsg(m)
+	}
+
+	HandleFunc("miek.nl.", handler)
+	defer HandleRemove("miek.nl.")
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %s", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeTXT)
+
+	// Add two local edns options to the query.
+	ec1 := &EDNS0_LOCAL{Code: 1979, Data: []byte{7, 7}}
+	ec2 := &EDNS0_LOCAL{Code: EDNS0LOCALSTART, Data: []byte{6, 1}}
+	o := &OPT{Hdr: RR_Header{Name: ".", Rrtype: TypeOPT}, Option: []EDNS0{ec1, ec2}}
+	m.Extra = append(m.Extra, o)
+
+	c := new(Client)
+	r, _, e := c.Exchange(m, addrstr)
+	if e != nil {
+		t.Logf("failed to exchange: %s", e.Error())
+		t.Fail()
+	}
+
+	if r != nil && r.Rcode != RcodeSuccess {
+		t.Log("failed to get a valid answer")
+		t.Fail()
+		t.Logf("%v\n", r)
+	}
+
+	txt := r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello local edns" {
+		t.Log("Unexpected result for miek.nl", txt, "!= Hello local edns")
+		t.Fail()
+	}
+
+	// Validate the local options in the reply.
+	got := r.Extra[1].(*OPT).Option[0].(*EDNS0_LOCAL).String()
+	if got != optStr1 {
+		t.Logf("failed to get local edns0 answer; got %s, expected %s", got, optStr1)
+		t.Fail()
+		t.Logf("%v\n", r)
+	}
+
+	got = r.Extra[1].(*OPT).Option[1].(*EDNS0_LOCAL).String()
+	if got != optStr2 {
+		t.Logf("failed to get local edns0 answer; got %s, expected %s", got, optStr2)
+		t.Fail()
+		t.Logf("%v\n", r)
+	}
+}
+
+// ExampleTsigSecret_updateLeaseTSIG shows how to update a lease signed with TSIG
+func ExampleTsigSecret_updateLeaseTSIG() {
+	m := new(Msg)
+	m.SetUpdate("t.local.ip6.io.")
+	rr, _ := NewRR("t.local.ip6.io. 30 A 127.0.0.1")
+	rrs := make([]RR, 1)
+	rrs[0] = rr
+	m.Insert(rrs)
+
+	leaseRr := new(OPT)
+	leaseRr.Hdr.Name = "."
+	leaseRr.Hdr.Rrtype = TypeOPT
+	e := new(EDNS0_UL)
+	e.Code = EDNS0UL
+	e.Lease = 120
+	leaseRr.Option = append(leaseRr.Option, e)
+	m.Extra = append(m.Extra, leaseRr)
+
+	c := new(Client)
+	m.SetTsig("polvi.", HmacMD5, 300, time.Now().Unix())
+	c.TsigSecret = map[string]string{"polvi.": "pRZgBrBvI4NAHZYhxmhs/Q=="}
+
+	_, _, err := c.Exchange(m, "127.0.0.1:53")
+	if err != nil {
+		panic(err)
+	}
+}
+
+func TestClientConn(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServer)
+	defer HandleRemove("miek.nl.")
+
+	// This uses TCP just to make it slightly different than TestClientSync
+	s, addrstr, err := RunLocalTCPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeSOA)
+
+	cn, err := Dial("tcp", addrstr)
+	if err != nil {
+		t.Errorf("failed to dial %s: %v", addrstr, err)
+	}
+
+	err = cn.WriteMsg(m)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	r, err := cn.ReadMsg()
+	if r == nil || r.Rcode != RcodeSuccess {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+
+	err = cn.WriteMsg(m)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	h := new(Header)
+	buf, err := cn.ReadMsgHeader(h)
+	if buf == nil {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+	if int(h.Bits&0xF) != RcodeSuccess {
+		t.Errorf("failed to get an valid answer in ReadMsgHeader\n%v", r)
+	}
+	if h.Ancount != 0 || h.Qdcount != 1 || h.Nscount != 0 || h.Arcount != 1 {
+		t.Errorf("expected to have question and additional in response; got something else: %+v", h)
+	}
+	if err = r.Unpack(buf); err != nil {
+		t.Errorf("unable to unpack message fully: %v", err)
+	}
+}
+
+func TestTruncatedMsg(t *testing.T) {
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeSRV)
+	cnt := 10
+	for i := 0; i < cnt; i++ {
+		r := &SRV{
+			Hdr:    RR_Header{Name: m.Question[0].Name, Rrtype: TypeSRV, Class: ClassINET, Ttl: 0},
+			Port:   uint16(i + 8000),
+			Target: "target.miek.nl.",
+		}
+		m.Answer = append(m.Answer, r)
+
+		re := &A{
+			Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeA, Class: ClassINET, Ttl: 0},
+			A:   net.ParseIP(fmt.Sprintf("127.0.0.%d", i)).To4(),
+		}
+		m.Extra = append(m.Extra, re)
+	}
+	buf, err := m.Pack()
+	if err != nil {
+		t.Errorf("failed to pack: %v", err)
+	}
+
+	r := new(Msg)
+	if err = r.Unpack(buf); err != nil {
+		t.Errorf("unable to unpack message: %v", err)
+	}
+	if len(r.Answer) != cnt {
+		t.Logf("answer count after regular unpack doesn't match: %d", len(r.Answer))
+		t.Fail()
+	}
+	if len(r.Extra) != cnt {
+		t.Logf("extra count after regular unpack doesn't match: %d", len(r.Extra))
+		t.Fail()
+	}
+
+	m.Truncated = true
+	buf, err = m.Pack()
+	if err != nil {
+		t.Errorf("failed to pack truncated: %v", err)
+	}
+
+	r = new(Msg)
+	if err = r.Unpack(buf); err != nil && err != ErrTruncated {
+		t.Errorf("unable to unpack truncated message: %v", err)
+	}
+	if !r.Truncated {
+		t.Log("truncated message wasn't unpacked as truncated")
+		t.Fail()
+	}
+	if len(r.Answer) != cnt {
+		t.Logf("answer count after truncated unpack doesn't match: %d", len(r.Answer))
+		t.Fail()
+	}
+	if len(r.Extra) != cnt {
+		t.Logf("extra count after truncated unpack doesn't match: %d", len(r.Extra))
+		t.Fail()
+	}
+
+	// Now we want to remove almost all of the extra records
+	// We're going to loop over the extra to get the count of the size of all
+	// of them
+	off := 0
+	buf1 := make([]byte, m.Len())
+	for i := 0; i < len(m.Extra); i++ {
+		off, err = PackRR(m.Extra[i], buf1, off, nil, m.Compress)
+		if err != nil {
+			t.Errorf("failed to pack extra: %v", err)
+		}
+	}
+
+	// Remove all of the extra bytes but 10 bytes from the end of buf
+	off -= 10
+	buf1 = buf[:len(buf)-off]
+
+	r = new(Msg)
+	if err = r.Unpack(buf1); err != nil && err != ErrTruncated {
+		t.Errorf("unable to unpack cutoff message: %v", err)
+	}
+	if !r.Truncated {
+		t.Log("truncated cutoff message wasn't unpacked as truncated")
+		t.Fail()
+	}
+	if len(r.Answer) != cnt {
+		t.Logf("answer count after cutoff unpack doesn't match: %d", len(r.Answer))
+		t.Fail()
+	}
+	if len(r.Extra) != 0 {
+		t.Logf("extra count after cutoff unpack is not zero: %d", len(r.Extra))
+		t.Fail()
+	}
+
+	// Now we want to remove almost all of the answer records too
+	buf1 = make([]byte, m.Len())
+	as := 0
+	for i := 0; i < len(m.Extra); i++ {
+		off1 := off
+		off, err = PackRR(m.Extra[i], buf1, off, nil, m.Compress)
+		as = off - off1
+		if err != nil {
+			t.Errorf("failed to pack extra: %v", err)
+		}
+	}
+
+	// Keep exactly one answer left
+	// This should still cause Answer to be nil
+	off -= as
+	buf1 = buf[:len(buf)-off]
+
+	r = new(Msg)
+	if err = r.Unpack(buf1); err != nil && err != ErrTruncated {
+		t.Errorf("unable to unpack cutoff message: %v", err)
+	}
+	if !r.Truncated {
+		t.Log("truncated cutoff message wasn't unpacked as truncated")
+		t.Fail()
+	}
+	if len(r.Answer) != 0 {
+		t.Logf("answer count after second cutoff unpack is not zero: %d", len(r.Answer))
+		t.Fail()
+	}
+
+	// Now leave only 1 byte of the question
+	// Since the header is always 12 bytes, we just need to keep 13
+	buf1 = buf[:13]
+
+	r = new(Msg)
+	err = r.Unpack(buf1)
+	if err == nil || err == ErrTruncated {
+		t.Logf("error should not be ErrTruncated from question cutoff unpack: %v", err)
+		t.Fail()
+	}
+
+	// Finally, if we only have the header, we should still return an error
+	buf1 = buf[:12]
+
+	r = new(Msg)
+	if err = r.Unpack(buf1); err == nil || err != ErrTruncated {
+		t.Logf("error not ErrTruncated from header-only unpack: %v", err)
+		t.Fail()
+	}
+}

clientconfig.go

@@ -0,0 +1,99 @@
+package dns
+
+import (
+	"bufio"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// ClientConfig wraps the contents of the /etc/resolv.conf file.
+type ClientConfig struct {
+	Servers  []string // servers to use
+	Search   []string // suffixes to append to local name
+	Port     string   // what port to use
+	Ndots    int      // number of dots in name to trigger absolute lookup
+	Timeout  int      // seconds before giving up on packet
+	Attempts int      // lost packets before giving up on server, not used in the package dns
+}
+
+// ClientConfigFromFile parses a resolv.conf(5) like file and returns
+// a *ClientConfig.
+func ClientConfigFromFile(resolvconf string) (*ClientConfig, error) {
+	file, err := os.Open(resolvconf)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	c := new(ClientConfig)
+	scanner := bufio.NewScanner(file)
+	c.Servers = make([]string, 0)
+	c.Search = make([]string, 0)
+	c.Port = "53"
+	c.Ndots = 1
+	c.Timeout = 5
+	c.Attempts = 2
+
+	for scanner.Scan() {
+		if err := scanner.Err(); err != nil {
+			return nil, err
+		}
+		line := scanner.Text()
+		f := strings.Fields(line)
+		if len(f) < 1 {
+			continue
+		}
+		switch f[0] {
+		case "nameserver": // add one name server
+			if len(f) > 1 {
+				// One more check: make sure server name is
+				// just an IP address.  Otherwise we need DNS
+				// to look it up.
+				name := f[1]
+				c.Servers = append(c.Servers, name)
+			}
+
+		case "domain": // set search path to just this domain
+			if len(f) > 1 {
+				c.Search = make([]string, 1)
+				c.Search[0] = f[1]
+			} else {
+				c.Search = make([]string, 0)
+			}
+
+		case "search": // set search path to given servers
+			c.Search = make([]string, len(f)-1)
+			for i := 0; i < len(c.Search); i++ {
+				c.Search[i] = f[i+1]
+			}
+
+		case "options": // magic options
+			for i := 1; i < len(f); i++ {
+				s := f[i]
+				switch {
+				case len(s) >= 6 && s[:6] == "ndots:":
+					n, _ := strconv.Atoi(s[6:])
+					if n < 1 {
+						n = 1
+					}
+					c.Ndots = n
+				case len(s) >= 8 && s[:8] == "timeout:":
+					n, _ := strconv.Atoi(s[8:])
+					if n < 1 {
+						n = 1
+					}
+					c.Timeout = n
+				case len(s) >= 8 && s[:9] == "attempts:":
+					n, _ := strconv.Atoi(s[9:])
+					if n < 1 {
+						n = 1
+					}
+					c.Attempts = n
+				case s == "rotate":
+					/* not imp */
+				}
+			}
+		}
+	}
+	return c, nil
+}

clientconfig_test.go

@@ -0,0 +1,50 @@
+package dns
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+const normal string = `
+# Comment
+domain somedomain.com
+nameserver 10.28.10.2
+nameserver 11.28.10.1
+`
+
+const missingNewline string = `
+domain somedomain.com
+nameserver 10.28.10.2
+nameserver 11.28.10.1` // <- NOTE: NO newline.
+
+func testConfig(t *testing.T, data string) {
+	tempDir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("tempDir: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	path := filepath.Join(tempDir, "resolv.conf")
+	if err := ioutil.WriteFile(path, []byte(data), 0644); err != nil {
+		t.Fatalf("writeFile: %v", err)
+	}
+	cc, err := ClientConfigFromFile(path)
+	if err != nil {
+		t.Errorf("error parsing resolv.conf: %v", err)
+	}
+	if l := len(cc.Servers); l != 2 {
+		t.Errorf("incorrect number of nameservers detected: %d", l)
+	}
+	if l := len(cc.Search); l != 1 {
+		t.Errorf("domain directive not parsed correctly: %v", cc.Search)
+	} else {
+		if cc.Search[0] != "somedomain.com" {
+			t.Errorf("domain is unexpected: %v", cc.Search[0])
+		}
+	}
+}
+
+func TestNameserver(t *testing.T)          { testConfig(t, normal) }
+func TestMissingFinalNewLine(t *testing.T) { testConfig(t, missingNewline) }

defaults.go

@@ -0,0 +1,278 @@
+package dns
+
+import (
+	"errors"
+	"net"
+	"strconv"
+)
+
+const hexDigit = "0123456789abcdef"
+
+// Everything is assumed in ClassINET.
+
+// SetReply creates a reply message from a request message.
+func (dns *Msg) SetReply(request *Msg) *Msg {
+	dns.Id = request.Id
+	dns.RecursionDesired = request.RecursionDesired // Copy rd bit
+	dns.Response = true
+	dns.Opcode = OpcodeQuery
+	dns.Rcode = RcodeSuccess
+	if len(request.Question) > 0 {
+		dns.Question = make([]Question, 1)
+		dns.Question[0] = request.Question[0]
+	}
+	return dns
+}
+
+// SetQuestion creates a question message, it sets the Question
+// section, generates an Id and sets the RecursionDesired (RD)
+// bit to true.
+func (dns *Msg) SetQuestion(z string, t uint16) *Msg {
+	dns.Id = Id()
+	dns.RecursionDesired = true
+	dns.Question = make([]Question, 1)
+	dns.Question[0] = Question{z, t, ClassINET}
+	return dns
+}
+
+// SetNotify creates a notify message, it sets the Question
+// section, generates an Id and sets the Authoritative (AA)
+// bit to true.
+func (dns *Msg) SetNotify(z string) *Msg {
+	dns.Opcode = OpcodeNotify
+	dns.Authoritative = true
+	dns.Id = Id()
+	dns.Question = make([]Question, 1)
+	dns.Question[0] = Question{z, TypeSOA, ClassINET}
+	return dns
+}
+
+// SetRcode creates an error message suitable for the request.
+func (dns *Msg) SetRcode(request *Msg, rcode int) *Msg {
+	dns.SetReply(request)
+	dns.Rcode = rcode
+	return dns
+}
+
+// SetRcodeFormatError creates a message with FormError set.
+func (dns *Msg) SetRcodeFormatError(request *Msg) *Msg {
+	dns.Rcode = RcodeFormatError
+	dns.Opcode = OpcodeQuery
+	dns.Response = true
+	dns.Authoritative = false
+	dns.Id = request.Id
+	return dns
+}
+
+// SetUpdate makes the message a dynamic update message. It
+// sets the ZONE section to: z, TypeSOA, ClassINET.
+func (dns *Msg) SetUpdate(z string) *Msg {
+	dns.Id = Id()
+	dns.Response = false
+	dns.Opcode = OpcodeUpdate
+	dns.Compress = false // BIND9 cannot handle compression
+	dns.Question = make([]Question, 1)
+	dns.Question[0] = Question{z, TypeSOA, ClassINET}
+	return dns
+}
+
+// SetIxfr creates message for requesting an IXFR.
+func (dns *Msg) SetIxfr(z string, serial uint32, ns, mbox string) *Msg {
+	dns.Id = Id()
+	dns.Question = make([]Question, 1)
+	dns.Ns = make([]RR, 1)
+	s := new(SOA)
+	s.Hdr = RR_Header{z, TypeSOA, ClassINET, defaultTtl, 0}
+	s.Serial = serial
+	s.Ns = ns
+	s.Mbox = mbox
+	dns.Question[0] = Question{z, TypeIXFR, ClassINET}
+	dns.Ns[0] = s
+	return dns
+}
+
+// SetAxfr creates message for requesting an AXFR.
+func (dns *Msg) SetAxfr(z string) *Msg {
+	dns.Id = Id()
+	dns.Question = make([]Question, 1)
+	dns.Question[0] = Question{z, TypeAXFR, ClassINET}
+	return dns
+}
+
+// SetTsig appends a TSIG RR to the message.
+// This is only a skeleton TSIG RR that is added as the last RR in the
+// additional section. The Tsig is calculated when the message is being send.
+func (dns *Msg) SetTsig(z, algo string, fudge, timesigned int64) *Msg {
+	t := new(TSIG)
+	t.Hdr = RR_Header{z, TypeTSIG, ClassANY, 0, 0}
+	t.Algorithm = algo
+	t.Fudge = 300
+	t.TimeSigned = uint64(timesigned)
+	t.OrigId = dns.Id
+	dns.Extra = append(dns.Extra, t)
+	return dns
+}
+
+// SetEdns0 appends a EDNS0 OPT RR to the message.
+// TSIG should always the last RR in a message.
+func (dns *Msg) SetEdns0(udpsize uint16, do bool) *Msg {
+	e := new(OPT)
+	e.Hdr.Name = "."
+	e.Hdr.Rrtype = TypeOPT
+	e.SetUDPSize(udpsize)
+	if do {
+		e.SetDo()
+	}
+	dns.Extra = append(dns.Extra, e)
+	return dns
+}
+
+// IsTsig checks if the message has a TSIG record as the last record
+// in the additional section. It returns the TSIG record found or nil.
+func (dns *Msg) IsTsig() *TSIG {
+	if len(dns.Extra) > 0 {
+		if dns.Extra[len(dns.Extra)-1].Header().Rrtype == TypeTSIG {
+			return dns.Extra[len(dns.Extra)-1].(*TSIG)
+		}
+	}
+	return nil
+}
+
+// IsEdns0 checks if the message has a EDNS0 (OPT) record, any EDNS0
+// record in the additional section will do. It returns the OPT record
+// found or nil.
+func (dns *Msg) IsEdns0() *OPT {
+	for _, r := range dns.Extra {
+		if r.Header().Rrtype == TypeOPT {
+			return r.(*OPT)
+		}
+	}
+	return nil
+}
+
+// IsDomainName checks if s is a valid domain name, it returns the number of
+// labels and true, when a domain name is valid.  Note that non fully qualified
+// domain name is considered valid, in this case the last label is counted in
+// the number of labels.  When false is returned the number of labels is not
+// defined.  Also note that this function is extremely liberal; almost any
+// string is a valid domain name as the DNS is 8 bit protocol. It checks if each
+// label fits in 63 characters, but there is no length check for the entire
+// string s. I.e.  a domain name longer than 255 characters is considered valid.
+func IsDomainName(s string) (labels int, ok bool) {
+	_, labels, err := packDomainName(s, nil, 0, nil, false)
+	return labels, err == nil
+}
+
+// IsSubDomain checks if child is indeed a child of the parent. Both child and
+// parent are *not* downcased before doing the comparison.
+func IsSubDomain(parent, child string) bool {
+	// Entire child is contained in parent
+	return CompareDomainName(parent, child) == CountLabel(parent)
+}
+
+// IsMsg sanity checks buf and returns an error if it isn't a valid DNS packet.
+// The checking is performed on the binary payload.
+func IsMsg(buf []byte) error {
+	// Header
+	if len(buf) < 12 {
+		return errors.New("dns: bad message header")
+	}
+	// Header: Opcode
+	// TODO(miek): more checks here, e.g. check all header bits.
+	return nil
+}
+
+// IsFqdn checks if a domain name is fully qualified.
+func IsFqdn(s string) bool {
+	l := len(s)
+	if l == 0 {
+		return false
+	}
+	return s[l-1] == '.'
+}
+
+// IsRRset checks if a set of RRs is a valid RRset as defined by RFC 2181.
+// This means the RRs need to have the same type, name, and class. Returns true
+// if the RR set is valid, otherwise false.
+func IsRRset(rrset []RR) bool {
+	if len(rrset) == 0 {
+		return false
+	}
+	if len(rrset) == 1 {
+		return true
+	}
+	rrHeader := rrset[0].Header()
+	rrType := rrHeader.Rrtype
+	rrClass := rrHeader.Class
+	rrName := rrHeader.Name
+
+	for _, rr := range rrset[1:] {
+		curRRHeader := rr.Header()
+		if curRRHeader.Rrtype != rrType || curRRHeader.Class != rrClass || curRRHeader.Name != rrName {
+			// Mismatch between the records, so this is not a valid rrset for
+			//signing/verifying
+			return false
+		}
+	}
+
+	return true
+}
+
+// Fqdn return the fully qualified domain name from s.
+// If s is already fully qualified, it behaves as the identity function.
+func Fqdn(s string) string {
+	if IsFqdn(s) {
+		return s
+	}
+	return s + "."
+}
+
+// Copied from the official Go code.
+
+// ReverseAddr returns the in-addr.arpa. or ip6.arpa. hostname of the IP
+// address suitable for reverse DNS (PTR) record lookups or an error if it fails
+// to parse the IP address.
+func ReverseAddr(addr string) (arpa string, err error) {
+	ip := net.ParseIP(addr)
+	if ip == nil {
+		return "", &Error{err: "unrecognized address: " + addr}
+	}
+	if ip.To4() != nil {
+		return strconv.Itoa(int(ip[15])) + "." + strconv.Itoa(int(ip[14])) + "." + strconv.Itoa(int(ip[13])) + "." +
+			strconv.Itoa(int(ip[12])) + ".in-addr.arpa.", nil
+	}
+	// Must be IPv6
+	buf := make([]byte, 0, len(ip)*4+len("ip6.arpa."))
+	// Add it, in reverse, to the buffer
+	for i := len(ip) - 1; i >= 0; i-- {
+		v := ip[i]
+		buf = append(buf, hexDigit[v&0xF])
+		buf = append(buf, '.')
+		buf = append(buf, hexDigit[v>>4])
+		buf = append(buf, '.')
+	}
+	// Append "ip6.arpa." and return (buf already has the final .)
+	buf = append(buf, "ip6.arpa."...)
+	return string(buf), nil
+}
+
+// String returns the string representation for the type t.
+func (t Type) String() string {
+	if t1, ok := TypeToString[uint16(t)]; ok {
+		return t1
+	}
+	return "TYPE" + strconv.Itoa(int(t))
+}
+
+// String returns the string representation for the class c.
+func (c Class) String() string {
+	if c1, ok := ClassToString[uint16(c)]; ok {
+		return c1
+	}
+	return "CLASS" + strconv.Itoa(int(c))
+}
+
+// String returns the string representation for the name n.
+func (n Name) String() string {
+	return sprintName(string(n))
+}

dns.go

@@ -0,0 +1,100 @@
+package dns
+
+import "strconv"
+
+const (
+	year68 = 1 << 31 // For RFC1982 (Serial Arithmetic) calculations in 32 bits.
+	// DefaultMsgSize is the standard default for messages larger than 512 bytes.
+	DefaultMsgSize = 4096
+	// MinMsgSize is the minimal size of a DNS packet.
+	MinMsgSize = 512
+	// MaxMsgSize is the largest possible DNS packet.
+	MaxMsgSize = 65535
+	defaultTtl = 3600 // Default internal TTL.
+)
+
+// Error represents a DNS error
+type Error struct{ err string }
+
+func (e *Error) Error() string {
+	if e == nil {
+		return "dns: <nil>"
+	}
+	return "dns: " + e.err
+}
+
+// An RR represents a resource record.
+type RR interface {
+	// Header returns the header of an resource record. The header contains
+	// everything up to the rdata.
+	Header() *RR_Header
+	// String returns the text representation of the resource record.
+	String() string
+	// copy returns a copy of the RR
+	copy() RR
+	// len returns the length (in octets) of the uncompressed RR in wire format.
+	len() int
+}
+
+// RR_Header is the header all DNS resource records share.
+type RR_Header struct {
+	Name     string `dns:"cdomain-name"`
+	Rrtype   uint16
+	Class    uint16
+	Ttl      uint32
+	Rdlength uint16 // length of data after header
+}
+
+// Header returns itself. This is here to make RR_Header implement the RR interface.
+func (h *RR_Header) Header() *RR_Header { return h }
+
+// Just to imlement the RR interface.
+func (h *RR_Header) copy() RR { return nil }
+
+func (h *RR_Header) copyHeader() *RR_Header {
+	r := new(RR_Header)
+	r.Name = h.Name
+	r.Rrtype = h.Rrtype
+	r.Class = h.Class
+	r.Ttl = h.Ttl
+	r.Rdlength = h.Rdlength
+	return r
+}
+
+func (h *RR_Header) String() string {
+	var s string
+
+	if h.Rrtype == TypeOPT {
+		s = ";"
+		// and maybe other things
+	}
+
+	s += sprintName(h.Name) + "\t"
+	s += strconv.FormatInt(int64(h.Ttl), 10) + "\t"
+	s += Class(h.Class).String() + "\t"
+	s += Type(h.Rrtype).String() + "\t"
+	return s
+}
+
+func (h *RR_Header) len() int {
+	l := len(h.Name) + 1
+	l += 10 // rrtype(2) + class(2) + ttl(4) + rdlength(2)
+	return l
+}
+
+// ToRFC3597 converts a known RR to the unknown RR representation
+// from RFC 3597.
+func (rr *RFC3597) ToRFC3597(r RR) error {
+	buf := make([]byte, r.len()*2)
+	off, err := PackStruct(r, buf, 0)
+	if err != nil {
+		return err
+	}
+	buf = buf[:off]
+	rawSetRdlength(buf, 0, off)
+	_, err = UnpackStruct(rr, buf, 0)
+	if err != nil {
+		return err
+	}
+	return nil
+}

dns_test.go

@@ -0,0 +1,578 @@
+package dns
+
+import (
+	"encoding/hex"
+	"net"
+	"testing"
+)
+
+func TestPackUnpack(t *testing.T) {
+	out := new(Msg)
+	out.Answer = make([]RR, 1)
+	key := new(DNSKEY)
+	key = &DNSKEY{Flags: 257, Protocol: 3, Algorithm: RSASHA1}
+	key.Hdr = RR_Header{Name: "miek.nl.", Rrtype: TypeDNSKEY, Class: ClassINET, Ttl: 3600}
+	key.PublicKey = "AwEAAaHIwpx3w4VHKi6i1LHnTaWeHCL154Jug0Rtc9ji5qwPXpBo6A5sRv7cSsPQKPIwxLpyCrbJ4mr2L0EPOdvP6z6YfljK2ZmTbogU9aSU2fiq/4wjxbdkLyoDVgtO+JsxNN4bjr4WcWhsmk1Hg93FV9ZpkWb0Tbad8DFqNDzr//kZ"
+
+	out.Answer[0] = key
+	msg, err := out.Pack()
+	if err != nil {
+		t.Error("failed to pack msg with DNSKEY")
+	}
+	in := new(Msg)
+	if in.Unpack(msg) != nil {
+		t.Error("failed to unpack msg with DNSKEY")
+	}
+
+	sig := new(RRSIG)
+	sig = &RRSIG{TypeCovered: TypeDNSKEY, Algorithm: RSASHA1, Labels: 2,
+		OrigTtl: 3600, Expiration: 4000, Inception: 4000, KeyTag: 34641, SignerName: "miek.nl.",
+		Signature: "AwEAAaHIwpx3w4VHKi6i1LHnTaWeHCL154Jug0Rtc9ji5qwPXpBo6A5sRv7cSsPQKPIwxLpyCrbJ4mr2L0EPOdvP6z6YfljK2ZmTbogU9aSU2fiq/4wjxbdkLyoDVgtO+JsxNN4bjr4WcWhsmk1Hg93FV9ZpkWb0Tbad8DFqNDzr//kZ"}
+	sig.Hdr = RR_Header{Name: "miek.nl.", Rrtype: TypeRRSIG, Class: ClassINET, Ttl: 3600}
+
+	out.Answer[0] = sig
+	msg, err = out.Pack()
+	if err != nil {
+		t.Error("failed to pack msg with RRSIG")
+	}
+
+	if in.Unpack(msg) != nil {
+		t.Error("failed to unpack msg with RRSIG")
+	}
+}
+
+func TestPackUnpack2(t *testing.T) {
+	m := new(Msg)
+	m.Extra = make([]RR, 1)
+	m.Answer = make([]RR, 1)
+	dom := "miek.nl."
+	rr := new(A)
+	rr.Hdr = RR_Header{Name: dom, Rrtype: TypeA, Class: ClassINET, Ttl: 0}
+	rr.A = net.IPv4(127, 0, 0, 1)
+
+	x := new(TXT)
+	x.Hdr = RR_Header{Name: dom, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}
+	x.Txt = []string{"heelalaollo"}
+
+	m.Extra[0] = x
+	m.Answer[0] = rr
+	_, err := m.Pack()
+	if err != nil {
+		t.Error("Packing failed: ", err)
+		return
+	}
+}
+
+func TestPackUnpack3(t *testing.T) {
+	m := new(Msg)
+	m.Extra = make([]RR, 2)
+	m.Answer = make([]RR, 1)
+	dom := "miek.nl."
+	rr := new(A)
+	rr.Hdr = RR_Header{Name: dom, Rrtype: TypeA, Class: ClassINET, Ttl: 0}
+	rr.A = net.IPv4(127, 0, 0, 1)
+
+	x1 := new(TXT)
+	x1.Hdr = RR_Header{Name: dom, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}
+	x1.Txt = []string{}
+
+	x2 := new(TXT)
+	x2.Hdr = RR_Header{Name: dom, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}
+	x2.Txt = []string{"heelalaollo"}
+
+	m.Extra[0] = x1
+	m.Extra[1] = x2
+	m.Answer[0] = rr
+	b, err := m.Pack()
+	if err != nil {
+		t.Error("packing failed: ", err)
+		return
+	}
+
+	var unpackMsg Msg
+	err = unpackMsg.Unpack(b)
+	if err != nil {
+		t.Error("unpacking failed")
+		return
+	}
+}
+
+func TestBailiwick(t *testing.T) {
+	yes := map[string]string{
+		"miek.nl": "ns.miek.nl",
+		".":       "miek.nl",
+	}
+	for parent, child := range yes {
+		if !IsSubDomain(parent, child) {
+			t.Errorf("%s should be child of %s", child, parent)
+			t.Errorf("comparelabels %d", CompareDomainName(parent, child))
+			t.Errorf("lenlabels %d %d", CountLabel(parent), CountLabel(child))
+		}
+	}
+	no := map[string]string{
+		"www.miek.nl":  "ns.miek.nl",
+		"m\\.iek.nl":   "ns.miek.nl",
+		"w\\.iek.nl":   "w.iek.nl",
+		"p\\\\.iek.nl": "ns.p.iek.nl", // p\\.iek.nl , literal \ in domain name
+		"miek.nl":      ".",
+	}
+	for parent, child := range no {
+		if IsSubDomain(parent, child) {
+			t.Errorf("%s should not be child of %s", child, parent)
+			t.Errorf("comparelabels %d", CompareDomainName(parent, child))
+			t.Errorf("lenlabels %d %d", CountLabel(parent), CountLabel(child))
+		}
+	}
+}
+
+func TestPack(t *testing.T) {
+	rr := []string{"US.    86400	IN	NSEC	0-.us. NS SOA RRSIG NSEC DNSKEY TYPE65534"}
+	m := new(Msg)
+	var err error
+	m.Answer = make([]RR, 1)
+	for _, r := range rr {
+		m.Answer[0], err = NewRR(r)
+		if err != nil {
+			t.Errorf("failed to create RR: %v", err)
+			continue
+		}
+		if _, err := m.Pack(); err != nil {
+			t.Errorf("packing failed: %v", err)
+		}
+	}
+	x := new(Msg)
+	ns, _ := NewRR("pool.ntp.org.   390 IN  NS  a.ntpns.org")
+	ns.(*NS).Ns = "a.ntpns.org"
+	x.Ns = append(m.Ns, ns)
+	x.Ns = append(m.Ns, ns)
+	x.Ns = append(m.Ns, ns)
+	// This crashes due to the fact the a.ntpns.org isn't a FQDN
+	// How to recover() from a remove panic()?
+	if _, err := x.Pack(); err == nil {
+		t.Error("packing should fail")
+	}
+	x.Answer = make([]RR, 1)
+	x.Answer[0], err = NewRR(rr[0])
+	if _, err := x.Pack(); err == nil {
+		t.Error("packing should fail")
+	}
+	x.Question = make([]Question, 1)
+	x.Question[0] = Question{";sd#edddds鍛↙赏‘℅∥↙xzztsestxssweewwsssstx@s@Z嵌e@cn.pool.ntp.org.", TypeA, ClassINET}
+	if _, err := x.Pack(); err == nil {
+		t.Error("packing should fail")
+	}
+}
+
+func TestPackNAPTR(t *testing.T) {
+	for _, n := range []string{
+		`apple.com. IN NAPTR   100 50 "se" "SIP+D2U" "" _sip._udp.apple.com.`,
+		`apple.com. IN NAPTR   90 50 "se" "SIP+D2T" "" _sip._tcp.apple.com.`,
+		`apple.com. IN NAPTR   50 50 "se" "SIPS+D2T" "" _sips._tcp.apple.com.`,
+	} {
+		rr, _ := NewRR(n)
+		msg := make([]byte, rr.len())
+		if off, err := PackRR(rr, msg, 0, nil, false); err != nil {
+			t.Errorf("packing failed: %v", err)
+			t.Errorf("length %d, need more than %d", rr.len(), off)
+		} else {
+			t.Logf("buf size needed: %d", off)
+		}
+	}
+}
+
+func TestCompressLength(t *testing.T) {
+	m := new(Msg)
+	m.SetQuestion("miek.nl", TypeMX)
+	ul := m.Len()
+	m.Compress = true
+	if ul != m.Len() {
+		t.Fatalf("should be equal")
+	}
+}
+
+// Does the predicted length match final packed length?
+func TestMsgCompressLength(t *testing.T) {
+	makeMsg := func(question string, ans, ns, e []RR) *Msg {
+		msg := new(Msg)
+		msg.SetQuestion(Fqdn(question), TypeANY)
+		msg.Answer = append(msg.Answer, ans...)
+		msg.Ns = append(msg.Ns, ns...)
+		msg.Extra = append(msg.Extra, e...)
+		msg.Compress = true
+		return msg
+	}
+
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	rrA, _ := NewRR(name1 + " 3600 IN A 192.0.2.1")
+	rrMx, _ := NewRR(name1 + " 3600 IN MX 10 " + name1)
+	tests := []*Msg{
+		makeMsg(name1, []RR{rrA}, nil, nil),
+		makeMsg(name1, []RR{rrMx, rrMx}, nil, nil)}
+
+	for _, msg := range tests {
+		predicted := msg.Len()
+		buf, err := msg.Pack()
+		if err != nil {
+			t.Error(err)
+		}
+		if predicted < len(buf) {
+			t.Errorf("predicted compressed length is wrong: predicted %s (len=%d) %d, actual %d",
+				msg.Question[0].Name, len(msg.Answer), predicted, len(buf))
+		}
+	}
+}
+
+func TestMsgLength(t *testing.T) {
+	makeMsg := func(question string, ans, ns, e []RR) *Msg {
+		msg := new(Msg)
+		msg.SetQuestion(Fqdn(question), TypeANY)
+		msg.Answer = append(msg.Answer, ans...)
+		msg.Ns = append(msg.Ns, ns...)
+		msg.Extra = append(msg.Extra, e...)
+		return msg
+	}
+
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	rrA, _ := NewRR(name1 + " 3600 IN A 192.0.2.1")
+	rrMx, _ := NewRR(name1 + " 3600 IN MX 10 " + name1)
+	tests := []*Msg{
+		makeMsg(name1, []RR{rrA}, nil, nil),
+		makeMsg(name1, []RR{rrMx, rrMx}, nil, nil)}
+
+	for _, msg := range tests {
+		predicted := msg.Len()
+		buf, err := msg.Pack()
+		if err != nil {
+			t.Error(err)
+		}
+		if predicted < len(buf) {
+			t.Errorf("predicted length is wrong: predicted %s (len=%d), actual %d",
+				msg.Question[0].Name, predicted, len(buf))
+		}
+	}
+}
+
+func TestMsgLength2(t *testing.T) {
+	// Serialized replies
+	var testMessages = []string{
+		// google.com. IN A?
+		"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",
+		// amazon.com. IN A? (reply has no EDNS0 record)
+		// TODO(miek): this one is off-by-one, need to find out why
+		//"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",
+		// yahoo.com. IN A?
+		"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",
+		// microsoft.com. IN A?
+		"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",
+		// google.com. IN MX?
+		"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",
+		// reddit.com. IN A?
+		"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",
+	}
+
+	for i, hexData := range testMessages {
+		// we won't fail the decoding of the hex
+		input, _ := hex.DecodeString(hexData)
+		m := new(Msg)
+		m.Unpack(input)
+		//println(m.String())
+		m.Compress = true
+		lenComp := m.Len()
+		b, _ := m.Pack()
+		pacComp := len(b)
+		m.Compress = false
+		lenUnComp := m.Len()
+		b, _ = m.Pack()
+		pacUnComp := len(b)
+		if pacComp+1 != lenComp {
+			t.Errorf("msg.Len(compressed)=%d actual=%d for test %d", lenComp, pacComp, i)
+		}
+		if pacUnComp+1 != lenUnComp {
+			t.Errorf("msg.Len(uncompressed)=%d actual=%d for test %d", lenUnComp, pacUnComp, i)
+		}
+	}
+}
+
+func TestMsgLengthCompressionMalformed(t *testing.T) {
+	// SOA with empty hostmaster, which is illegal
+	soa := &SOA{Hdr: RR_Header{Name: ".", Rrtype: TypeSOA, Class: ClassINET, Ttl: 12345},
+		Ns:      ".",
+		Mbox:    "",
+		Serial:  0,
+		Refresh: 28800,
+		Retry:   7200,
+		Expire:  604800,
+		Minttl:  60}
+	m := new(Msg)
+	m.Compress = true
+	m.Ns = []RR{soa}
+	m.Len() // Should not crash.
+}
+
+func BenchmarkMsgLength(b *testing.B) {
+	b.StopTimer()
+	makeMsg := func(question string, ans, ns, e []RR) *Msg {
+		msg := new(Msg)
+		msg.SetQuestion(Fqdn(question), TypeANY)
+		msg.Answer = append(msg.Answer, ans...)
+		msg.Ns = append(msg.Ns, ns...)
+		msg.Extra = append(msg.Extra, e...)
+		msg.Compress = true
+		return msg
+	}
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	rrMx, _ := NewRR(name1 + " 3600 IN MX 10 " + name1)
+	msg := makeMsg(name1, []RR{rrMx, rrMx}, nil, nil)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		msg.Len()
+	}
+}
+
+func BenchmarkMsgLengthPack(b *testing.B) {
+	makeMsg := func(question string, ans, ns, e []RR) *Msg {
+		msg := new(Msg)
+		msg.SetQuestion(Fqdn(question), TypeANY)
+		msg.Answer = append(msg.Answer, ans...)
+		msg.Ns = append(msg.Ns, ns...)
+		msg.Extra = append(msg.Extra, e...)
+		msg.Compress = true
+		return msg
+	}
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	rrMx, _ := NewRR(name1 + " 3600 IN MX 10 " + name1)
+	msg := makeMsg(name1, []RR{rrMx, rrMx}, nil, nil)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = msg.Pack()
+	}
+}
+
+func BenchmarkMsgPackBuffer(b *testing.B) {
+	makeMsg := func(question string, ans, ns, e []RR) *Msg {
+		msg := new(Msg)
+		msg.SetQuestion(Fqdn(question), TypeANY)
+		msg.Answer = append(msg.Answer, ans...)
+		msg.Ns = append(msg.Ns, ns...)
+		msg.Extra = append(msg.Extra, e...)
+		msg.Compress = true
+		return msg
+	}
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	rrMx, _ := NewRR(name1 + " 3600 IN MX 10 " + name1)
+	msg := makeMsg(name1, []RR{rrMx, rrMx}, nil, nil)
+	buf := make([]byte, 512)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = msg.PackBuffer(buf)
+	}
+}
+
+func BenchmarkMsgUnpack(b *testing.B) {
+	makeMsg := func(question string, ans, ns, e []RR) *Msg {
+		msg := new(Msg)
+		msg.SetQuestion(Fqdn(question), TypeANY)
+		msg.Answer = append(msg.Answer, ans...)
+		msg.Ns = append(msg.Ns, ns...)
+		msg.Extra = append(msg.Extra, e...)
+		msg.Compress = true
+		return msg
+	}
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	rrMx, _ := NewRR(name1 + " 3600 IN MX 10 " + name1)
+	msg := makeMsg(name1, []RR{rrMx, rrMx}, nil, nil)
+	msgBuf, _ := msg.Pack()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = msg.Unpack(msgBuf)
+	}
+}
+
+func BenchmarkPackDomainName(b *testing.B) {
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	buf := make([]byte, len(name1)+1)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = PackDomainName(name1, buf, 0, nil, false)
+	}
+}
+
+func BenchmarkUnpackDomainName(b *testing.B) {
+	name1 := "12345678901234567890123456789012345.12345678.123."
+	buf := make([]byte, len(name1)+1)
+	_, _ = PackDomainName(name1, buf, 0, nil, false)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _, _ = UnpackDomainName(buf, 0)
+	}
+}
+
+func BenchmarkUnpackDomainNameUnprintable(b *testing.B) {
+	name1 := "\x02\x02\x02\x025\x02\x02\x02\x02.12345678.123."
+	buf := make([]byte, len(name1)+1)
+	_, _ = PackDomainName(name1, buf, 0, nil, false)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _, _ = UnpackDomainName(buf, 0)
+	}
+}
+
+func TestToRFC3597(t *testing.T) {
+	a, _ := NewRR("miek.nl. IN A 10.0.1.1")
+	x := new(RFC3597)
+	x.ToRFC3597(a)
+	if x.String() != `miek.nl.	3600	CLASS1	TYPE1	\# 4 0a000101` {
+		t.Error("string mismatch")
+	}
+}
+
+func TestNoRdataPack(t *testing.T) {
+	data := make([]byte, 1024)
+	for typ, fn := range TypeToRR {
+		r := fn()
+		*r.Header() = RR_Header{Name: "miek.nl.", Rrtype: typ, Class: ClassINET, Ttl: 3600}
+		_, err := PackRR(r, data, 0, nil, false)
+		if err != nil {
+			t.Errorf("failed to pack RR with zero rdata: %s: %v", TypeToString[typ], err)
+		}
+	}
+}
+
+// TODO(miek): fix dns buffer too small errors this throws
+func TestNoRdataUnpack(t *testing.T) {
+	data := make([]byte, 1024)
+	for typ, fn := range TypeToRR {
+		if typ == TypeSOA || typ == TypeTSIG || typ == TypeWKS {
+			// SOA, TSIG will not be seen (like this) in dyn. updates?
+			// WKS is an bug, but...deprecated record.
+			continue
+		}
+		r := fn()
+		*r.Header() = RR_Header{Name: "miek.nl.", Rrtype: typ, Class: ClassINET, Ttl: 3600}
+		off, err := PackRR(r, data, 0, nil, false)
+		if err != nil {
+			// Should always works, TestNoDataPack should have caught this
+			t.Errorf("failed to pack RR: %v", err)
+			continue
+		}
+		rr, _, err := UnpackRR(data[:off], 0)
+		if err != nil {
+			t.Errorf("failed to unpack RR with zero rdata: %s: %v", TypeToString[typ], err)
+		}
+		t.Log(rr)
+	}
+}
+
+func TestRdataOverflow(t *testing.T) {
+	rr := new(RFC3597)
+	rr.Hdr.Name = "."
+	rr.Hdr.Class = ClassINET
+	rr.Hdr.Rrtype = 65280
+	rr.Rdata = hex.EncodeToString(make([]byte, 0xFFFF))
+	buf := make([]byte, 0xFFFF*2)
+	if _, err := PackRR(rr, buf, 0, nil, false); err != nil {
+		t.Fatalf("maximum size rrdata pack failed: %v", err)
+	}
+	rr.Rdata += "00"
+	if _, err := PackRR(rr, buf, 0, nil, false); err != ErrRdata {
+		t.Fatalf("oversize rrdata pack didn't return ErrRdata - instead: %v", err)
+	}
+}
+
+func TestCopy(t *testing.T) {
+	rr, _ := NewRR("miek.nl. 2311 IN A 127.0.0.1") // Weird TTL to avoid catching TTL
+	rr1 := Copy(rr)
+	if rr.String() != rr1.String() {
+		t.Fatalf("Copy() failed %s != %s", rr.String(), rr1.String())
+	}
+}
+
+func TestMsgCopy(t *testing.T) {
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeA)
+	rr, _ := NewRR("miek.nl. 2311 IN A 127.0.0.1")
+	m.Answer = []RR{rr}
+	rr, _ = NewRR("miek.nl. 2311 IN NS 127.0.0.1")
+	m.Ns = []RR{rr}
+
+	m1 := m.Copy()
+	if m.String() != m1.String() {
+		t.Fatalf("Msg.Copy() failed %s != %s", m.String(), m1.String())
+	}
+
+	m1.Answer[0], _ = NewRR("somethingelse.nl. 2311 IN A 127.0.0.1")
+	if m.String() == m1.String() {
+		t.Fatalf("Msg.Copy() failed; change to copy changed template %s", m.String())
+	}
+
+	rr, _ = NewRR("miek.nl. 2311 IN A 127.0.0.2")
+	m1.Answer = append(m1.Answer, rr)
+	if m1.Ns[0].String() == m1.Answer[1].String() {
+		t.Fatalf("Msg.Copy() failed; append changed underlying array %s", m1.Ns[0].String())
+	}
+}
+
+func BenchmarkCopy(b *testing.B) {
+	b.ReportAllocs()
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeA)
+	rr, _ := NewRR("miek.nl. 2311 IN A 127.0.0.1")
+	m.Answer = []RR{rr}
+	rr, _ = NewRR("miek.nl. 2311 IN NS 127.0.0.1")
+	m.Ns = []RR{rr}
+	rr, _ = NewRR("miek.nl. 2311 IN A 127.0.0.1")
+	m.Extra = []RR{rr}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		m.Copy()
+	}
+}
+
+func TestPackIPSECKEY(t *testing.T) {
+	tests := []string{
+		"38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2 192.0.2.38 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )",
+		"38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 0 2 .  AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )",
+		"38.2.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 1 2 192.0.2.3 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )",
+		"38.1.0.192.in-addr.arpa. 7200 IN     IPSECKEY ( 10 3 2 mygateway.example.com.  AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )",
+		"0.d.4.0.3.0.e.f.f.f.3.f.0.1.2.0 7200 IN     IPSECKEY ( 10 2 2 2001:0DB8:0:8002::2000:1 AQNRU3mG7TVTO2BkR47usntb102uFJtugbo6BSGvgqt4AQ== )",
+	}
+	buf := make([]byte, 1024)
+	for _, t1 := range tests {
+		rr, _ := NewRR(t1)
+		off, err := PackRR(rr, buf, 0, nil, false)
+		if err != nil {
+			t.Errorf("failed to pack IPSECKEY %v: %s", err, t1)
+			continue
+		}
+
+		rr, _, err = UnpackRR(buf[:off], 0)
+		if err != nil {
+			t.Errorf("failed to unpack IPSECKEY %v: %s", err, t1)
+		}
+		t.Log(rr)
+	}
+}
+
+func TestMsgPackBuffer(t *testing.T) {
+	var testMessages = []string{
+		// news.ycombinator.com.in.escapemg.com.	IN	A, response
+		"586285830001000000010000046e6577730b79636f6d62696e61746f7203636f6d02696e086573636170656d6703636f6d0000010001c0210006000100000e10002c036e7332c02103646e730b67726f6f7665736861726bc02d77ed50e600002a3000000e1000093a8000000e10",
+
+		// news.ycombinator.com.in.escapemg.com.	IN	A, question
+		"586201000001000000000000046e6577730b79636f6d62696e61746f7203636f6d02696e086573636170656d6703636f6d0000010001",
+
+		"398781020001000000000000046e6577730b79636f6d62696e61746f7203636f6d0000010001",
+	}
+
+	for i, hexData := range testMessages {
+		// we won't fail the decoding of the hex
+		input, _ := hex.DecodeString(hexData)
+		m := new(Msg)
+		if err := m.Unpack(input); err != nil {
+			t.Errorf("packet %d failed to unpack", i)
+			continue
+		}
+		t.Logf("packet %d %s", i, m.String())
+	}
+}

dnssec.go

@@ -0,0 +1,664 @@
+package dns
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	_ "crypto/md5"
+	"crypto/rand"
+	"crypto/rsa"
+	_ "crypto/sha1"
+	_ "crypto/sha256"
+	_ "crypto/sha512"
+	"encoding/asn1"
+	"encoding/hex"
+	"math/big"
+	"sort"
+	"strings"
+	"time"
+)
+
+// DNSSEC encryption algorithm codes.
+const (
+	_ uint8 = iota
+	RSAMD5
+	DH
+	DSA
+	_ // Skip 4, RFC 6725, section 2.1
+	RSASHA1
+	DSANSEC3SHA1
+	RSASHA1NSEC3SHA1
+	RSASHA256
+	_ // Skip 9, RFC 6725, section 2.1
+	RSASHA512
+	_ // Skip 11, RFC 6725, section 2.1
+	ECCGOST
+	ECDSAP256SHA256
+	ECDSAP384SHA384
+	INDIRECT   uint8 = 252
+	PRIVATEDNS uint8 = 253 // Private (experimental keys)
+	PRIVATEOID uint8 = 254
+)
+
+// Map for algorithm names.
+var AlgorithmToString = map[uint8]string{
+	RSAMD5:           "RSAMD5",
+	DH:               "DH",
+	DSA:              "DSA",
+	RSASHA1:          "RSASHA1",
+	DSANSEC3SHA1:     "DSA-NSEC3-SHA1",
+	RSASHA1NSEC3SHA1: "RSASHA1-NSEC3-SHA1",
+	RSASHA256:        "RSASHA256",
+	RSASHA512:        "RSASHA512",
+	ECCGOST:          "ECC-GOST",
+	ECDSAP256SHA256:  "ECDSAP256SHA256",
+	ECDSAP384SHA384:  "ECDSAP384SHA384",
+	INDIRECT:         "INDIRECT",
+	PRIVATEDNS:       "PRIVATEDNS",
+	PRIVATEOID:       "PRIVATEOID",
+}
+
+// Map of algorithm strings.
+var StringToAlgorithm = reverseInt8(AlgorithmToString)
+
+// Map of algorithm crypto hashes.
+var AlgorithmToHash = map[uint8]crypto.Hash{
+	RSAMD5:           crypto.MD5, // Deprecated in RFC 6725
+	RSASHA1:          crypto.SHA1,
+	RSASHA1NSEC3SHA1: crypto.SHA1,
+	RSASHA256:        crypto.SHA256,
+	ECDSAP256SHA256:  crypto.SHA256,
+	ECDSAP384SHA384:  crypto.SHA384,
+	RSASHA512:        crypto.SHA512,
+}
+
+// DNSSEC hashing algorithm codes.
+const (
+	_      uint8 = iota
+	SHA1         // RFC 4034
+	SHA256       // RFC 4509
+	GOST94       // RFC 5933
+	SHA384       // Experimental
+	SHA512       // Experimental
+)
+
+// Map for hash names.
+var HashToString = map[uint8]string{
+	SHA1:   "SHA1",
+	SHA256: "SHA256",
+	GOST94: "GOST94",
+	SHA384: "SHA384",
+	SHA512: "SHA512",
+}
+
+// Map of hash strings.
+var StringToHash = reverseInt8(HashToString)
+
+// DNSKEY flag values.
+const (
+	SEP    = 1
+	REVOKE = 1 << 7
+	ZONE   = 1 << 8
+)
+
+// The RRSIG needs to be converted to wireformat with some of
+// the rdata (the signature) missing. Use this struct to ease
+// the conversion (and re-use the pack/unpack functions).
+type rrsigWireFmt struct {
+	TypeCovered uint16
+	Algorithm   uint8
+	Labels      uint8
+	OrigTtl     uint32
+	Expiration  uint32
+	Inception   uint32
+	KeyTag      uint16
+	SignerName  string `dns:"domain-name"`
+	/* No Signature */
+}
+
+// Used for converting DNSKEY's rdata to wirefmt.
+type dnskeyWireFmt struct {
+	Flags     uint16
+	Protocol  uint8
+	Algorithm uint8
+	PublicKey string `dns:"base64"`
+	/* Nothing is left out */
+}
+
+func divRoundUp(a, b int) int {
+	return (a + b - 1) / b
+}
+
+// KeyTag calculates the keytag (or key-id) of the DNSKEY.
+func (k *DNSKEY) KeyTag() uint16 {
+	if k == nil {
+		return 0
+	}
+	var keytag int
+	switch k.Algorithm {
+	case RSAMD5:
+		// Look at the bottom two bytes of the modules, which the last
+		// item in the pubkey. We could do this faster by looking directly
+		// at the base64 values. But I'm lazy.
+		modulus, _ := fromBase64([]byte(k.PublicKey))
+		if len(modulus) > 1 {
+			x, _ := unpackUint16(modulus, len(modulus)-2)
+			keytag = int(x)
+		}
+	default:
+		keywire := new(dnskeyWireFmt)
+		keywire.Flags = k.Flags
+		keywire.Protocol = k.Protocol
+		keywire.Algorithm = k.Algorithm
+		keywire.PublicKey = k.PublicKey
+		wire := make([]byte, DefaultMsgSize)
+		n, err := PackStruct(keywire, wire, 0)
+		if err != nil {
+			return 0
+		}
+		wire = wire[:n]
+		for i, v := range wire {
+			if i&1 != 0 {
+				keytag += int(v) // must be larger than uint32
+			} else {
+				keytag += int(v) << 8
+			}
+		}
+		keytag += (keytag >> 16) & 0xFFFF
+		keytag &= 0xFFFF
+	}
+	return uint16(keytag)
+}
+
+// ToDS converts a DNSKEY record to a DS record.
+func (k *DNSKEY) ToDS(h uint8) *DS {
+	if k == nil {
+		return nil
+	}
+	ds := new(DS)
+	ds.Hdr.Name = k.Hdr.Name
+	ds.Hdr.Class = k.Hdr.Class
+	ds.Hdr.Rrtype = TypeDS
+	ds.Hdr.Ttl = k.Hdr.Ttl
+	ds.Algorithm = k.Algorithm
+	ds.DigestType = h
+	ds.KeyTag = k.KeyTag()
+
+	keywire := new(dnskeyWireFmt)
+	keywire.Flags = k.Flags
+	keywire.Protocol = k.Protocol
+	keywire.Algorithm = k.Algorithm
+	keywire.PublicKey = k.PublicKey
+	wire := make([]byte, DefaultMsgSize)
+	n, err := PackStruct(keywire, wire, 0)
+	if err != nil {
+		return nil
+	}
+	wire = wire[:n]
+
+	owner := make([]byte, 255)
+	off, err1 := PackDomainName(strings.ToLower(k.Hdr.Name), owner, 0, nil, false)
+	if err1 != nil {
+		return nil
+	}
+	owner = owner[:off]
+	// RFC4034:
+	// digest = digest_algorithm( DNSKEY owner name | DNSKEY RDATA);
+	// "|" denotes concatenation
+	// DNSKEY RDATA = Flags | Protocol | Algorithm | Public Key.
+
+	// digest buffer
+	digest := append(owner, wire...) // another copy
+
+	var hash crypto.Hash
+	switch h {
+	case SHA1:
+		hash = crypto.SHA1
+	case SHA256:
+		hash = crypto.SHA256
+	case SHA384:
+		hash = crypto.SHA384
+	case SHA512:
+		hash = crypto.SHA512
+	default:
+		return nil
+	}
+
+	s := hash.New()
+	s.Write(digest)
+	ds.Digest = hex.EncodeToString(s.Sum(nil))
+	return ds
+}
+
+// ToCDNSKEY converts a DNSKEY record to a CDNSKEY record.
+func (k *DNSKEY) ToCDNSKEY() *CDNSKEY {
+	c := &CDNSKEY{DNSKEY: *k}
+	c.Hdr = *k.Hdr.copyHeader()
+	c.Hdr.Rrtype = TypeCDNSKEY
+	return c
+}
+
+// ToCDS converts a DS record to a CDS record.
+func (d *DS) ToCDS() *CDS {
+	c := &CDS{DS: *d}
+	c.Hdr = *d.Hdr.copyHeader()
+	c.Hdr.Rrtype = TypeCDS
+	return c
+}
+
+// Sign signs an RRSet. The signature needs to be filled in with the values:
+// Inception, Expiration, KeyTag, SignerName and Algorithm.  The rest is copied
+// from the RRset. Sign returns a non-nill error when the signing went OK.
+// There is no check if RRSet is a proper (RFC 2181) RRSet.  If OrigTTL is non
+// zero, it is used as-is, otherwise the TTL of the RRset is used as the
+// OrigTTL.
+func (rr *RRSIG) Sign(k crypto.Signer, rrset []RR) error {
+	if k == nil {
+		return ErrPrivKey
+	}
+	// s.Inception and s.Expiration may be 0 (rollover etc.), the rest must be set
+	if rr.KeyTag == 0 || len(rr.SignerName) == 0 || rr.Algorithm == 0 {
+		return ErrKey
+	}
+
+	rr.Hdr.Rrtype = TypeRRSIG
+	rr.Hdr.Name = rrset[0].Header().Name
+	rr.Hdr.Class = rrset[0].Header().Class
+	if rr.OrigTtl == 0 { // If set don't override
+		rr.OrigTtl = rrset[0].Header().Ttl
+	}
+	rr.TypeCovered = rrset[0].Header().Rrtype
+	rr.Labels = uint8(CountLabel(rrset[0].Header().Name))
+
+	if strings.HasPrefix(rrset[0].Header().Name, "*") {
+		rr.Labels-- // wildcard, remove from label count
+	}
+
+	sigwire := new(rrsigWireFmt)
+	sigwire.TypeCovered = rr.TypeCovered
+	sigwire.Algorithm = rr.Algorithm
+	sigwire.Labels = rr.Labels
+	sigwire.OrigTtl = rr.OrigTtl
+	sigwire.Expiration = rr.Expiration
+	sigwire.Inception = rr.Inception
+	sigwire.KeyTag = rr.KeyTag
+	// For signing, lowercase this name
+	sigwire.SignerName = strings.ToLower(rr.SignerName)
+
+	// Create the desired binary blob
+	signdata := make([]byte, DefaultMsgSize)
+	n, err := PackStruct(sigwire, signdata, 0)
+	if err != nil {
+		return err
+	}
+	signdata = signdata[:n]
+	wire, err := rawSignatureData(rrset, rr)
+	if err != nil {
+		return err
+	}
+	signdata = append(signdata, wire...)
+
+	hash, ok := AlgorithmToHash[rr.Algorithm]
+	if !ok {
+		return ErrAlg
+	}
+
+	h := hash.New()
+	h.Write(signdata)
+
+	signature, err := sign(k, h.Sum(nil), hash, rr.Algorithm)
+	if err != nil {
+		return err
+	}
+
+	rr.Signature = toBase64(signature)
+
+	return nil
+}
+
+func sign(k crypto.Signer, hashed []byte, hash crypto.Hash, alg uint8) ([]byte, error) {
+	signature, err := k.Sign(rand.Reader, hashed, hash)
+	if err != nil {
+		return nil, err
+	}
+
+	switch alg {
+	case RSASHA1, RSASHA1NSEC3SHA1, RSASHA256, RSASHA512:
+		return signature, nil
+
+	case ECDSAP256SHA256, ECDSAP384SHA384:
+		ecdsaSignature := &struct {
+			R, S *big.Int
+		}{}
+		if _, err := asn1.Unmarshal(signature, ecdsaSignature); err != nil {
+			return nil, err
+		}
+
+		var intlen int
+		switch alg {
+		case ECDSAP256SHA256:
+			intlen = 32
+		case ECDSAP384SHA384:
+			intlen = 48
+		}
+
+		signature := intToBytes(ecdsaSignature.R, intlen)
+		signature = append(signature, intToBytes(ecdsaSignature.S, intlen)...)
+		return signature, nil
+
+	// There is no defined interface for what a DSA backed crypto.Signer returns
+	case DSA, DSANSEC3SHA1:
+		// 	t := divRoundUp(divRoundUp(p.PublicKey.Y.BitLen(), 8)-64, 8)
+		// 	signature := []byte{byte(t)}
+		// 	signature = append(signature, intToBytes(r1, 20)...)
+		// 	signature = append(signature, intToBytes(s1, 20)...)
+		// 	rr.Signature = signature
+	}
+
+	return nil, ErrAlg
+}
+
+// Verify validates an RRSet with the signature and key. This is only the
+// cryptographic test, the signature validity period must be checked separately.
+// This function copies the rdata of some RRs (to lowercase domain names) for the validation to work.
+func (rr *RRSIG) Verify(k *DNSKEY, rrset []RR) error {
+	// First the easy checks
+	if !IsRRset(rrset) {
+		return ErrRRset
+	}
+	if rr.KeyTag != k.KeyTag() {
+		return ErrKey
+	}
+	if rr.Hdr.Class != k.Hdr.Class {
+		return ErrKey
+	}
+	if rr.Algorithm != k.Algorithm {
+		return ErrKey
+	}
+	if strings.ToLower(rr.SignerName) != strings.ToLower(k.Hdr.Name) {
+		return ErrKey
+	}
+	if k.Protocol != 3 {
+		return ErrKey
+	}
+
+	// IsRRset checked that we have at least one RR and that the RRs in
+	// the set have consistent type, class, and name. Also check that type and
+	// class matches the RRSIG record.
+	if rrset[0].Header().Class != rr.Hdr.Class {
+		return ErrRRset
+	}
+	if rrset[0].Header().Rrtype != rr.TypeCovered {
+		return ErrRRset
+	}
+
+	// RFC 4035 5.3.2.  Reconstructing the Signed Data
+	// Copy the sig, except the rrsig data
+	sigwire := new(rrsigWireFmt)
+	sigwire.TypeCovered = rr.TypeCovered
+	sigwire.Algorithm = rr.Algorithm
+	sigwire.Labels = rr.Labels
+	sigwire.OrigTtl = rr.OrigTtl
+	sigwire.Expiration = rr.Expiration
+	sigwire.Inception = rr.Inception
+	sigwire.KeyTag = rr.KeyTag
+	sigwire.SignerName = strings.ToLower(rr.SignerName)
+	// Create the desired binary blob
+	signeddata := make([]byte, DefaultMsgSize)
+	n, err := PackStruct(sigwire, signeddata, 0)
+	if err != nil {
+		return err
+	}
+	signeddata = signeddata[:n]
+	wire, err := rawSignatureData(rrset, rr)
+	if err != nil {
+		return err
+	}
+	signeddata = append(signeddata, wire...)
+
+	sigbuf := rr.sigBuf()           // Get the binary signature data
+	if rr.Algorithm == PRIVATEDNS { // PRIVATEOID
+		// TODO(miek)
+		// remove the domain name and assume its ours?
+	}
+
+	hash, ok := AlgorithmToHash[rr.Algorithm]
+	if !ok {
+		return ErrAlg
+	}
+
+	switch rr.Algorithm {
+	case RSASHA1, RSASHA1NSEC3SHA1, RSASHA256, RSASHA512, RSAMD5:
+		// TODO(mg): this can be done quicker, ie. cache the pubkey data somewhere??
+		pubkey := k.publicKeyRSA() // Get the key
+		if pubkey == nil {
+			return ErrKey
+		}
+
+		h := hash.New()
+		h.Write(signeddata)
+		return rsa.VerifyPKCS1v15(pubkey, hash, h.Sum(nil), sigbuf)
+
+	case ECDSAP256SHA256, ECDSAP384SHA384:
+		pubkey := k.publicKeyECDSA()
+		if pubkey == nil {
+			return ErrKey
+		}
+
+		// Split sigbuf into the r and s coordinates
+		r := new(big.Int).SetBytes(sigbuf[:len(sigbuf)/2])
+		s := new(big.Int).SetBytes(sigbuf[len(sigbuf)/2:])
+
+		h := hash.New()
+		h.Write(signeddata)
+		if ecdsa.Verify(pubkey, h.Sum(nil), r, s) {
+			return nil
+		}
+		return ErrSig
+
+	default:
+		return ErrAlg
+	}
+}
+
+// ValidityPeriod uses RFC1982 serial arithmetic to calculate
+// if a signature period is valid. If t is the zero time, the
+// current time is taken other t is. Returns true if the signature
+// is valid at the given time, otherwise returns false.
+func (rr *RRSIG) ValidityPeriod(t time.Time) bool {
+	var utc int64
+	if t.IsZero() {
+		utc = time.Now().UTC().Unix()
+	} else {
+		utc = t.UTC().Unix()
+	}
+	modi := (int64(rr.Inception) - utc) / year68
+	mode := (int64(rr.Expiration) - utc) / year68
+	ti := int64(rr.Inception) + (modi * year68)
+	te := int64(rr.Expiration) + (mode * year68)
+	return ti <= utc && utc <= te
+}
+
+// Return the signatures base64 encodedig sigdata as a byte slice.
+func (rr *RRSIG) sigBuf() []byte {
+	sigbuf, err := fromBase64([]byte(rr.Signature))
+	if err != nil {
+		return nil
+	}
+	return sigbuf
+}
+
+// publicKeyRSA returns the RSA public key from a DNSKEY record.
+func (k *DNSKEY) publicKeyRSA() *rsa.PublicKey {
+	keybuf, err := fromBase64([]byte(k.PublicKey))
+	if err != nil {
+		return nil
+	}
+
+	// RFC 2537/3110, section 2. RSA Public KEY Resource Records
+	// Length is in the 0th byte, unless its zero, then it
+	// it in bytes 1 and 2 and its a 16 bit number
+	explen := uint16(keybuf[0])
+	keyoff := 1
+	if explen == 0 {
+		explen = uint16(keybuf[1])<<8 | uint16(keybuf[2])
+		keyoff = 3
+	}
+	pubkey := new(rsa.PublicKey)
+
+	pubkey.N = big.NewInt(0)
+	shift := uint64((explen - 1) * 8)
+	expo := uint64(0)
+	for i := int(explen - 1); i > 0; i-- {
+		expo += uint64(keybuf[keyoff+i]) << shift
+		shift -= 8
+	}
+	// Remainder
+	expo += uint64(keybuf[keyoff])
+	if expo > 2<<31 {
+		// Larger expo than supported.
+		// println("dns: F5 primes (or larger) are not supported")
+		return nil
+	}
+	pubkey.E = int(expo)
+
+	pubkey.N.SetBytes(keybuf[keyoff+int(explen):])
+	return pubkey
+}
+
+// publicKeyECDSA returns the Curve public key from the DNSKEY record.
+func (k *DNSKEY) publicKeyECDSA() *ecdsa.PublicKey {
+	keybuf, err := fromBase64([]byte(k.PublicKey))
+	if err != nil {
+		return nil
+	}
+	pubkey := new(ecdsa.PublicKey)
+	switch k.Algorithm {
+	case ECDSAP256SHA256:
+		pubkey.Curve = elliptic.P256()
+		if len(keybuf) != 64 {
+			// wrongly encoded key
+			return nil
+		}
+	case ECDSAP384SHA384:
+		pubkey.Curve = elliptic.P384()
+		if len(keybuf) != 96 {
+			// Wrongly encoded key
+			return nil
+		}
+	}
+	pubkey.X = big.NewInt(0)
+	pubkey.X.SetBytes(keybuf[:len(keybuf)/2])
+	pubkey.Y = big.NewInt(0)
+	pubkey.Y.SetBytes(keybuf[len(keybuf)/2:])
+	return pubkey
+}
+
+func (k *DNSKEY) publicKeyDSA() *dsa.PublicKey {
+	keybuf, err := fromBase64([]byte(k.PublicKey))
+	if err != nil {
+		return nil
+	}
+	if len(keybuf) < 22 {
+		return nil
+	}
+	t, keybuf := int(keybuf[0]), keybuf[1:]
+	size := 64 + t*8
+	q, keybuf := keybuf[:20], keybuf[20:]
+	if len(keybuf) != 3*size {
+		return nil
+	}
+	p, keybuf := keybuf[:size], keybuf[size:]
+	g, y := keybuf[:size], keybuf[size:]
+	pubkey := new(dsa.PublicKey)
+	pubkey.Parameters.Q = big.NewInt(0).SetBytes(q)
+	pubkey.Parameters.P = big.NewInt(0).SetBytes(p)
+	pubkey.Parameters.G = big.NewInt(0).SetBytes(g)
+	pubkey.Y = big.NewInt(0).SetBytes(y)
+	return pubkey
+}
+
+type wireSlice [][]byte
+
+func (p wireSlice) Len() int      { return len(p) }
+func (p wireSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
+func (p wireSlice) Less(i, j int) bool {
+	_, ioff, _ := UnpackDomainName(p[i], 0)
+	_, joff, _ := UnpackDomainName(p[j], 0)
+	return bytes.Compare(p[i][ioff+10:], p[j][joff+10:]) < 0
+}
+
+// Return the raw signature data.
+func rawSignatureData(rrset []RR, s *RRSIG) (buf []byte, err error) {
+	wires := make(wireSlice, len(rrset))
+	for i, r := range rrset {
+		r1 := r.copy()
+		r1.Header().Ttl = s.OrigTtl
+		labels := SplitDomainName(r1.Header().Name)
+		// 6.2. Canonical RR Form. (4) - wildcards
+		if len(labels) > int(s.Labels) {
+			// Wildcard
+			r1.Header().Name = "*." + strings.Join(labels[len(labels)-int(s.Labels):], ".") + "."
+		}
+		// RFC 4034: 6.2.  Canonical RR Form. (2) - domain name to lowercase
+		r1.Header().Name = strings.ToLower(r1.Header().Name)
+		// 6.2. Canonical RR Form. (3) - domain rdata to lowercase.
+		//   NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
+		//   HINFO, MINFO, MX, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX,
+		//   SRV, DNAME, A6
+		//
+		// RFC 6840 - Clarifications and Implementation Notes for DNS Security (DNSSEC):
+		//	Section 6.2 of [RFC4034] also erroneously lists HINFO as a record
+		//	that needs conversion to lowercase, and twice at that.  Since HINFO
+		//	records contain no domain names, they are not subject to case
+		//	conversion.
+		switch x := r1.(type) {
+		case *NS:
+			x.Ns = strings.ToLower(x.Ns)
+		case *CNAME:
+			x.Target = strings.ToLower(x.Target)
+		case *SOA:
+			x.Ns = strings.ToLower(x.Ns)
+			x.Mbox = strings.ToLower(x.Mbox)
+		case *MB:
+			x.Mb = strings.ToLower(x.Mb)
+		case *MG:
+			x.Mg = strings.ToLower(x.Mg)
+		case *MR:
+			x.Mr = strings.ToLower(x.Mr)
+		case *PTR:
+			x.Ptr = strings.ToLower(x.Ptr)
+		case *MINFO:
+			x.Rmail = strings.ToLower(x.Rmail)
+			x.Email = strings.ToLower(x.Email)
+		case *MX:
+			x.Mx = strings.ToLower(x.Mx)
+		case *NAPTR:
+			x.Replacement = strings.ToLower(x.Replacement)
+		case *KX:
+			x.Exchanger = strings.ToLower(x.Exchanger)
+		case *SRV:
+			x.Target = strings.ToLower(x.Target)
+		case *DNAME:
+			x.Target = strings.ToLower(x.Target)
+		}
+		// 6.2. Canonical RR Form. (5) - origTTL
+		wire := make([]byte, r1.len()+1) // +1 to be safe(r)
+		off, err1 := PackRR(r1, wire, 0, nil, false)
+		if err1 != nil {
+			return nil, err1
+		}
+		wire = wire[:off]
+		wires[i] = wire
+	}
+	sort.Sort(wires)
+	for i, wire := range wires {
+		if i > 0 && bytes.Equal(wire, wires[i-1]) {
+			continue
+		}
+		buf = append(buf, wire...)
+	}
+	return buf, nil
+}

dnssec_keygen.go

@@ -0,0 +1,156 @@
+package dns
+
+import (
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	"math/big"
+)
+
+// Generate generates a DNSKEY of the given bit size.
+// The public part is put inside the DNSKEY record.
+// The Algorithm in the key must be set as this will define
+// what kind of DNSKEY will be generated.
+// The ECDSA algorithms imply a fixed keysize, in that case
+// bits should be set to the size of the algorithm.
+func (k *DNSKEY) Generate(bits int) (crypto.PrivateKey, error) {
+	switch k.Algorithm {
+	case DSA, DSANSEC3SHA1:
+		if bits != 1024 {
+			return nil, ErrKeySize
+		}
+	case RSAMD5, RSASHA1, RSASHA256, RSASHA1NSEC3SHA1:
+		if bits < 512 || bits > 4096 {
+			return nil, ErrKeySize
+		}
+	case RSASHA512:
+		if bits < 1024 || bits > 4096 {
+			return nil, ErrKeySize
+		}
+	case ECDSAP256SHA256:
+		if bits != 256 {
+			return nil, ErrKeySize
+		}
+	case ECDSAP384SHA384:
+		if bits != 384 {
+			return nil, ErrKeySize
+		}
+	}
+
+	switch k.Algorithm {
+	case DSA, DSANSEC3SHA1:
+		params := new(dsa.Parameters)
+		if err := dsa.GenerateParameters(params, rand.Reader, dsa.L1024N160); err != nil {
+			return nil, err
+		}
+		priv := new(dsa.PrivateKey)
+		priv.PublicKey.Parameters = *params
+		err := dsa.GenerateKey(priv, rand.Reader)
+		if err != nil {
+			return nil, err
+		}
+		k.setPublicKeyDSA(params.Q, params.P, params.G, priv.PublicKey.Y)
+		return priv, nil
+	case RSAMD5, RSASHA1, RSASHA256, RSASHA512, RSASHA1NSEC3SHA1:
+		priv, err := rsa.GenerateKey(rand.Reader, bits)
+		if err != nil {
+			return nil, err
+		}
+		k.setPublicKeyRSA(priv.PublicKey.E, priv.PublicKey.N)
+		return priv, nil
+	case ECDSAP256SHA256, ECDSAP384SHA384:
+		var c elliptic.Curve
+		switch k.Algorithm {
+		case ECDSAP256SHA256:
+			c = elliptic.P256()
+		case ECDSAP384SHA384:
+			c = elliptic.P384()
+		}
+		priv, err := ecdsa.GenerateKey(c, rand.Reader)
+		if err != nil {
+			return nil, err
+		}
+		k.setPublicKeyECDSA(priv.PublicKey.X, priv.PublicKey.Y)
+		return priv, nil
+	default:
+		return nil, ErrAlg
+	}
+}
+
+// Set the public key (the value E and N)
+func (k *DNSKEY) setPublicKeyRSA(_E int, _N *big.Int) bool {
+	if _E == 0 || _N == nil {
+		return false
+	}
+	buf := exponentToBuf(_E)
+	buf = append(buf, _N.Bytes()...)
+	k.PublicKey = toBase64(buf)
+	return true
+}
+
+// Set the public key for Elliptic Curves
+func (k *DNSKEY) setPublicKeyECDSA(_X, _Y *big.Int) bool {
+	if _X == nil || _Y == nil {
+		return false
+	}
+	var intlen int
+	switch k.Algorithm {
+	case ECDSAP256SHA256:
+		intlen = 32
+	case ECDSAP384SHA384:
+		intlen = 48
+	}
+	k.PublicKey = toBase64(curveToBuf(_X, _Y, intlen))
+	return true
+}
+
+// Set the public key for DSA
+func (k *DNSKEY) setPublicKeyDSA(_Q, _P, _G, _Y *big.Int) bool {
+	if _Q == nil || _P == nil || _G == nil || _Y == nil {
+		return false
+	}
+	buf := dsaToBuf(_Q, _P, _G, _Y)
+	k.PublicKey = toBase64(buf)
+	return true
+}
+
+// Set the public key (the values E and N) for RSA
+// RFC 3110: Section 2. RSA Public KEY Resource Records
+func exponentToBuf(_E int) []byte {
+	var buf []byte
+	i := big.NewInt(int64(_E))
+	if len(i.Bytes()) < 256 {
+		buf = make([]byte, 1)
+		buf[0] = uint8(len(i.Bytes()))
+	} else {
+		buf = make([]byte, 3)
+		buf[0] = 0
+		buf[1] = uint8(len(i.Bytes()) >> 8)
+		buf[2] = uint8(len(i.Bytes()))
+	}
+	buf = append(buf, i.Bytes()...)
+	return buf
+}
+
+// Set the public key for X and Y for Curve. The two
+// values are just concatenated.
+func curveToBuf(_X, _Y *big.Int, intlen int) []byte {
+	buf := intToBytes(_X, intlen)
+	buf = append(buf, intToBytes(_Y, intlen)...)
+	return buf
+}
+
+// Set the public key for X and Y for Curve. The two
+// values are just concatenated.
+func dsaToBuf(_Q, _P, _G, _Y *big.Int) []byte {
+	t := divRoundUp(divRoundUp(_G.BitLen(), 8)-64, 8)
+	buf := []byte{byte(t)}
+	buf = append(buf, intToBytes(_Q, 20)...)
+	buf = append(buf, intToBytes(_P, 64+t*8)...)
+	buf = append(buf, intToBytes(_G, 64+t*8)...)
+	buf = append(buf, intToBytes(_Y, 64+t*8)...)
+	return buf
+}

dnssec_keyscan.go

@@ -0,0 +1,249 @@
+package dns
+
+import (
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"io"
+	"math/big"
+	"strconv"
+	"strings"
+)
+
+// NewPrivateKey returns a PrivateKey by parsing the string s.
+// s should be in the same form of the BIND private key files.
+func (k *DNSKEY) NewPrivateKey(s string) (crypto.PrivateKey, error) {
+	if s[len(s)-1] != '\n' { // We need a closing newline
+		return k.ReadPrivateKey(strings.NewReader(s+"\n"), "")
+	}
+	return k.ReadPrivateKey(strings.NewReader(s), "")
+}
+
+// ReadPrivateKey reads a private key from the io.Reader q. The string file is
+// only used in error reporting.
+// The public key must be known, because some cryptographic algorithms embed
+// the public inside the privatekey.
+func (k *DNSKEY) ReadPrivateKey(q io.Reader, file string) (crypto.PrivateKey, error) {
+	m, e := parseKey(q, file)
+	if m == nil {
+		return nil, e
+	}
+	if _, ok := m["private-key-format"]; !ok {
+		return nil, ErrPrivKey
+	}
+	if m["private-key-format"] != "v1.2" && m["private-key-format"] != "v1.3" {
+		return nil, ErrPrivKey
+	}
+	// TODO(mg): check if the pubkey matches the private key
+	algo, err := strconv.Atoi(strings.SplitN(m["algorithm"], " ", 2)[0])
+	if err != nil {
+		return nil, ErrPrivKey
+	}
+	switch uint8(algo) {
+	case DSA:
+		priv, e := readPrivateKeyDSA(m)
+		if e != nil {
+			return nil, e
+		}
+		pub := k.publicKeyDSA()
+		if pub == nil {
+			return nil, ErrKey
+		}
+		priv.PublicKey = *pub
+		return priv, e
+	case RSAMD5:
+		fallthrough
+	case RSASHA1:
+		fallthrough
+	case RSASHA1NSEC3SHA1:
+		fallthrough
+	case RSASHA256:
+		fallthrough
+	case RSASHA512:
+		priv, e := readPrivateKeyRSA(m)
+		if e != nil {
+			return nil, e
+		}
+		pub := k.publicKeyRSA()
+		if pub == nil {
+			return nil, ErrKey
+		}
+		priv.PublicKey = *pub
+		return priv, e
+	case ECCGOST:
+		return nil, ErrPrivKey
+	case ECDSAP256SHA256:
+		fallthrough
+	case ECDSAP384SHA384:
+		priv, e := readPrivateKeyECDSA(m)
+		if e != nil {
+			return nil, e
+		}
+		pub := k.publicKeyECDSA()
+		if pub == nil {
+			return nil, ErrKey
+		}
+		priv.PublicKey = *pub
+		return priv, e
+	default:
+		return nil, ErrPrivKey
+	}
+}
+
+// Read a private key (file) string and create a public key. Return the private key.
+func readPrivateKeyRSA(m map[string]string) (*rsa.PrivateKey, error) {
+	p := new(rsa.PrivateKey)
+	p.Primes = []*big.Int{nil, nil}
+	for k, v := range m {
+		switch k {
+		case "modulus", "publicexponent", "privateexponent", "prime1", "prime2":
+			v1, err := fromBase64([]byte(v))
+			if err != nil {
+				return nil, err
+			}
+			switch k {
+			case "modulus":
+				p.PublicKey.N = big.NewInt(0)
+				p.PublicKey.N.SetBytes(v1)
+			case "publicexponent":
+				i := big.NewInt(0)
+				i.SetBytes(v1)
+				p.PublicKey.E = int(i.Int64()) // int64 should be large enough
+			case "privateexponent":
+				p.D = big.NewInt(0)
+				p.D.SetBytes(v1)
+			case "prime1":
+				p.Primes[0] = big.NewInt(0)
+				p.Primes[0].SetBytes(v1)
+			case "prime2":
+				p.Primes[1] = big.NewInt(0)
+				p.Primes[1].SetBytes(v1)
+			}
+		case "exponent1", "exponent2", "coefficient":
+			// not used in Go (yet)
+		case "created", "publish", "activate":
+			// not used in Go (yet)
+		}
+	}
+	return p, nil
+}
+
+func readPrivateKeyDSA(m map[string]string) (*dsa.PrivateKey, error) {
+	p := new(dsa.PrivateKey)
+	p.X = big.NewInt(0)
+	for k, v := range m {
+		switch k {
+		case "private_value(x)":
+			v1, err := fromBase64([]byte(v))
+			if err != nil {
+				return nil, err
+			}
+			p.X.SetBytes(v1)
+		case "created", "publish", "activate":
+			/* not used in Go (yet) */
+		}
+	}
+	return p, nil
+}
+
+func readPrivateKeyECDSA(m map[string]string) (*ecdsa.PrivateKey, error) {
+	p := new(ecdsa.PrivateKey)
+	p.D = big.NewInt(0)
+	// TODO: validate that the required flags are present
+	for k, v := range m {
+		switch k {
+		case "privatekey":
+			v1, err := fromBase64([]byte(v))
+			if err != nil {
+				return nil, err
+			}
+			p.D.SetBytes(v1)
+		case "created", "publish", "activate":
+			/* not used in Go (yet) */
+		}
+	}
+	return p, nil
+}
+
+// parseKey reads a private key from r. It returns a map[string]string,
+// with the key-value pairs, or an error when the file is not correct.
+func parseKey(r io.Reader, file string) (map[string]string, error) {
+	s := scanInit(r)
+	m := make(map[string]string)
+	c := make(chan lex)
+	k := ""
+	// Start the lexer
+	go klexer(s, c)
+	for l := range c {
+		// It should alternate
+		switch l.value {
+		case zKey:
+			k = l.token
+		case zValue:
+			if k == "" {
+				return nil, &ParseError{file, "no private key seen", l}
+			}
+			//println("Setting", strings.ToLower(k), "to", l.token, "b")
+			m[strings.ToLower(k)] = l.token
+			k = ""
+		}
+	}
+	return m, nil
+}
+
+// klexer scans the sourcefile and returns tokens on the channel c.
+func klexer(s *scan, c chan lex) {
+	var l lex
+	str := "" // Hold the current read text
+	commt := false
+	key := true
+	x, err := s.tokenText()
+	defer close(c)
+	for err == nil {
+		l.column = s.position.Column
+		l.line = s.position.Line
+		switch x {
+		case ':':
+			if commt {
+				break
+			}
+			l.token = str
+			if key {
+				l.value = zKey
+				c <- l
+				// Next token is a space, eat it
+				s.tokenText()
+				key = false
+				str = ""
+			} else {
+				l.value = zValue
+			}
+		case ';':
+			commt = true
+		case '\n':
+			if commt {
+				// Reset a comment
+				commt = false
+			}
+			l.value = zValue
+			l.token = str
+			c <- l
+			str = ""
+			commt = false
+			key = true
+		default:
+			if commt {
+				break
+			}
+			str += string(x)
+		}
+		x, err = s.tokenText()
+	}
+	if len(str) > 0 {
+		// Send remainder
+		l.token = str
+		l.value = zValue
+		c <- l
+	}
+}

dnssec_privkey.go

@@ -0,0 +1,85 @@
+package dns
+
+import (
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"math/big"
+	"strconv"
+)
+
+const format = "Private-key-format: v1.3\n"
+
+// PrivateKeyString converts a PrivateKey to a string. This string has the same
+// format as the private-key-file of BIND9 (Private-key-format: v1.3).
+// It needs some info from the key (the algorithm), so its a method of the DNSKEY
+// It supports rsa.PrivateKey, ecdsa.PrivateKey and dsa.PrivateKey
+func (r *DNSKEY) PrivateKeyString(p crypto.PrivateKey) string {
+	algorithm := strconv.Itoa(int(r.Algorithm))
+	algorithm += " (" + AlgorithmToString[r.Algorithm] + ")"
+
+	switch p := p.(type) {
+	case *rsa.PrivateKey:
+		modulus := toBase64(p.PublicKey.N.Bytes())
+		e := big.NewInt(int64(p.PublicKey.E))
+		publicExponent := toBase64(e.Bytes())
+		privateExponent := toBase64(p.D.Bytes())
+		prime1 := toBase64(p.Primes[0].Bytes())
+		prime2 := toBase64(p.Primes[1].Bytes())
+		// Calculate Exponent1/2 and Coefficient as per: http://en.wikipedia.org/wiki/RSA#Using_the_Chinese_remainder_algorithm
+		// and from: http://code.google.com/p/go/issues/detail?id=987
+		one := big.NewInt(1)
+		p1 := big.NewInt(0).Sub(p.Primes[0], one)
+		q1 := big.NewInt(0).Sub(p.Primes[1], one)
+		exp1 := big.NewInt(0).Mod(p.D, p1)
+		exp2 := big.NewInt(0).Mod(p.D, q1)
+		coeff := big.NewInt(0).ModInverse(p.Primes[1], p.Primes[0])
+
+		exponent1 := toBase64(exp1.Bytes())
+		exponent2 := toBase64(exp2.Bytes())
+		coefficient := toBase64(coeff.Bytes())
+
+		return format +
+			"Algorithm: " + algorithm + "\n" +
+			"Modulus: " + modulus + "\n" +
+			"PublicExponent: " + publicExponent + "\n" +
+			"PrivateExponent: " + privateExponent + "\n" +
+			"Prime1: " + prime1 + "\n" +
+			"Prime2: " + prime2 + "\n" +
+			"Exponent1: " + exponent1 + "\n" +
+			"Exponent2: " + exponent2 + "\n" +
+			"Coefficient: " + coefficient + "\n"
+
+	case *ecdsa.PrivateKey:
+		var intlen int
+		switch r.Algorithm {
+		case ECDSAP256SHA256:
+			intlen = 32
+		case ECDSAP384SHA384:
+			intlen = 48
+		}
+		private := toBase64(intToBytes(p.D, intlen))
+		return format +
+			"Algorithm: " + algorithm + "\n" +
+			"PrivateKey: " + private + "\n"
+
+	case *dsa.PrivateKey:
+		T := divRoundUp(divRoundUp(p.PublicKey.Parameters.G.BitLen(), 8)-64, 8)
+		prime := toBase64(intToBytes(p.PublicKey.Parameters.P, 64+T*8))
+		subprime := toBase64(intToBytes(p.PublicKey.Parameters.Q, 20))
+		base := toBase64(intToBytes(p.PublicKey.Parameters.G, 64+T*8))
+		priv := toBase64(intToBytes(p.X, 20))
+		pub := toBase64(intToBytes(p.PublicKey.Y, 64+T*8))
+		return format +
+			"Algorithm: " + algorithm + "\n" +
+			"Prime(p): " + prime + "\n" +
+			"Subprime(q): " + subprime + "\n" +
+			"Base(g): " + base + "\n" +
+			"Private_value(x): " + priv + "\n" +
+			"Public_value(y): " + pub + "\n"
+
+	default:
+		return ""
+	}
+}

dnssec_test.go

@@ -0,0 +1,733 @@
+package dns
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+func getKey() *DNSKEY {
+	key := new(DNSKEY)
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	key.PublicKey = "AwEAAcNEU67LJI5GEgF9QLNqLO1SMq1EdoQ6E9f85ha0k0ewQGCblyW2836GiVsm6k8Kr5ECIoMJ6fZWf3CQSQ9ycWfTyOHfmI3eQ/1Covhb2y4bAmL/07PhrL7ozWBW3wBfM335Ft9xjtXHPy7ztCbV9qZ4TVDTW/Iyg0PiwgoXVesz"
+	return key
+}
+
+func getSoa() *SOA {
+	soa := new(SOA)
+	soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}
+	soa.Ns = "open.nlnetlabs.nl."
+	soa.Mbox = "miekg.atoom.net."
+	soa.Serial = 1293945905
+	soa.Refresh = 14400
+	soa.Retry = 3600
+	soa.Expire = 604800
+	soa.Minttl = 86400
+	return soa
+}
+
+func TestGenerateEC(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+	key := new(DNSKEY)
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = ECDSAP256SHA256
+	privkey, _ := key.Generate(256)
+	t.Log(key.String())
+	t.Log(key.PrivateKeyString(privkey))
+}
+
+func TestGenerateDSA(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+	key := new(DNSKEY)
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = DSA
+	privkey, _ := key.Generate(1024)
+	t.Log(key.String())
+	t.Log(key.PrivateKeyString(privkey))
+}
+
+func TestGenerateRSA(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+	key := new(DNSKEY)
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	privkey, _ := key.Generate(1024)
+	t.Log(key.String())
+	t.Log(key.PrivateKeyString(privkey))
+}
+
+func TestSecure(t *testing.T) {
+	soa := getSoa()
+
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.TypeCovered = TypeSOA
+	sig.Algorithm = RSASHA256
+	sig.Labels = 2
+	sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
+	sig.Inception = 1293942305  // date -u '+%s' -d"2011-01-02 04:25:05"
+	sig.OrigTtl = 14400
+	sig.KeyTag = 12051
+	sig.SignerName = "miek.nl."
+	sig.Signature = "oMCbslaAVIp/8kVtLSms3tDABpcPRUgHLrOR48OOplkYo+8TeEGWwkSwaz/MRo2fB4FxW0qj/hTlIjUGuACSd+b1wKdH5GvzRJc2pFmxtCbm55ygAh4EUL0F6U5cKtGJGSXxxg6UFCQ0doJCmiGFa78LolaUOXImJrk6AFrGa0M="
+
+	key := new(DNSKEY)
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	key.PublicKey = "AwEAAcNEU67LJI5GEgF9QLNqLO1SMq1EdoQ6E9f85ha0k0ewQGCblyW2836GiVsm6k8Kr5ECIoMJ6fZWf3CQSQ9ycWfTyOHfmI3eQ/1Covhb2y4bAmL/07PhrL7ozWBW3wBfM335Ft9xjtXHPy7ztCbV9qZ4TVDTW/Iyg0PiwgoXVesz"
+
+	// It should validate. Period is checked separately, so this will keep on working
+	if sig.Verify(key, []RR{soa}) != nil {
+		t.Error("failure to validate")
+	}
+}
+
+func TestSignature(t *testing.T) {
+	sig := new(RRSIG)
+	sig.Hdr.Name = "miek.nl."
+	sig.Hdr.Class = ClassINET
+	sig.Hdr.Ttl = 3600
+	sig.TypeCovered = TypeDNSKEY
+	sig.Algorithm = RSASHA1
+	sig.Labels = 2
+	sig.OrigTtl = 4000
+	sig.Expiration = 1000 //Thu Jan  1 02:06:40 CET 1970
+	sig.Inception = 800   //Thu Jan  1 01:13:20 CET 1970
+	sig.KeyTag = 34641
+	sig.SignerName = "miek.nl."
+	sig.Signature = "AwEAAaHIwpx3w4VHKi6i1LHnTaWeHCL154Jug0Rtc9ji5qwPXpBo6A5sRv7cSsPQKPIwxLpyCrbJ4mr2L0EPOdvP6z6YfljK2ZmTbogU9aSU2fiq/4wjxbdkLyoDVgtO+JsxNN4bjr4WcWhsmk1Hg93FV9ZpkWb0Tbad8DFqNDzr//kZ"
+
+	// Should not be valid
+	if sig.ValidityPeriod(time.Now()) {
+		t.Error("should not be valid")
+	}
+
+	sig.Inception = 315565800   //Tue Jan  1 10:10:00 CET 1980
+	sig.Expiration = 4102477800 //Fri Jan  1 10:10:00 CET 2100
+	if !sig.ValidityPeriod(time.Now()) {
+		t.Error("should be valid")
+	}
+}
+
+func TestSignVerify(t *testing.T) {
+	// The record we want to sign
+	soa := new(SOA)
+	soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}
+	soa.Ns = "open.nlnetlabs.nl."
+	soa.Mbox = "miekg.atoom.net."
+	soa.Serial = 1293945905
+	soa.Refresh = 14400
+	soa.Retry = 3600
+	soa.Expire = 604800
+	soa.Minttl = 86400
+
+	soa1 := new(SOA)
+	soa1.Hdr = RR_Header{"*.miek.nl.", TypeSOA, ClassINET, 14400, 0}
+	soa1.Ns = "open.nlnetlabs.nl."
+	soa1.Mbox = "miekg.atoom.net."
+	soa1.Serial = 1293945905
+	soa1.Refresh = 14400
+	soa1.Retry = 3600
+	soa1.Expire = 604800
+	soa1.Minttl = 86400
+
+	srv := new(SRV)
+	srv.Hdr = RR_Header{"srv.miek.nl.", TypeSRV, ClassINET, 14400, 0}
+	srv.Port = 1000
+	srv.Weight = 800
+	srv.Target = "web1.miek.nl."
+
+	hinfo := &HINFO{
+		Hdr: RR_Header{
+			Name:   "miek.nl.",
+			Rrtype: TypeHINFO,
+			Class:  ClassINET,
+			Ttl:    3789,
+		},
+		Cpu: "X",
+		Os:  "Y",
+	}
+
+	// With this key
+	key := new(DNSKEY)
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	privkey, _ := key.Generate(512)
+
+	// Fill in the values of the Sig, before signing
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.TypeCovered = soa.Hdr.Rrtype
+	sig.Labels = uint8(CountLabel(soa.Hdr.Name)) // works for all 3
+	sig.OrigTtl = soa.Hdr.Ttl
+	sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
+	sig.Inception = 1293942305  // date -u '+%s' -d"2011-01-02 04:25:05"
+	sig.KeyTag = key.KeyTag()   // Get the keyfrom the Key
+	sig.SignerName = key.Hdr.Name
+	sig.Algorithm = RSASHA256
+
+	for _, r := range []RR{soa, soa1, srv, hinfo} {
+		if err := sig.Sign(privkey.(*rsa.PrivateKey), []RR{r}); err != nil {
+			t.Error("failure to sign the record:", err)
+			continue
+		}
+		if err := sig.Verify(key, []RR{r}); err != nil {
+			t.Error("failure to validate")
+			continue
+		}
+		t.Logf("validated: %s", r.Header().Name)
+	}
+}
+
+func Test65534(t *testing.T) {
+	t6 := new(RFC3597)
+	t6.Hdr = RR_Header{"miek.nl.", 65534, ClassINET, 14400, 0}
+	t6.Rdata = "505D870001"
+	key := new(DNSKEY)
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	privkey, _ := key.Generate(1024)
+
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.TypeCovered = t6.Hdr.Rrtype
+	sig.Labels = uint8(CountLabel(t6.Hdr.Name))
+	sig.OrigTtl = t6.Hdr.Ttl
+	sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
+	sig.Inception = 1293942305  // date -u '+%s' -d"2011-01-02 04:25:05"
+	sig.KeyTag = key.KeyTag()
+	sig.SignerName = key.Hdr.Name
+	sig.Algorithm = RSASHA256
+	if err := sig.Sign(privkey.(*rsa.PrivateKey), []RR{t6}); err != nil {
+		t.Error(err)
+		t.Error("failure to sign the TYPE65534 record")
+	}
+	if err := sig.Verify(key, []RR{t6}); err != nil {
+		t.Error(err)
+		t.Error("failure to validate")
+	} else {
+		t.Logf("validated: %s", t6.Header().Name)
+	}
+}
+
+func TestDnskey(t *testing.T) {
+	pubkey, err := ReadRR(strings.NewReader(`
+miek.nl.	IN	DNSKEY	256 3 10 AwEAAZuMCu2FdugHkTrXYgl5qixvcDw1aDDlvL46/xJKbHBAHY16fNUb2b65cwko2Js/aJxUYJbZk5dwCDZxYfrfbZVtDPQuc3o8QaChVxC7/JYz2AHc9qHvqQ1j4VrH71RWINlQo6VYjzN/BGpMhOZoZOEwzp1HfsOE3lNYcoWU1smL ;{id = 5240 (zsk), size = 1024b}
+`), "Kmiek.nl.+010+05240.key")
+	if err != nil {
+		t.Fatal(err)
+	}
+	privStr := `Private-key-format: v1.3
+Algorithm: 10 (RSASHA512)
+Modulus: m4wK7YV26AeROtdiCXmqLG9wPDVoMOW8vjr/EkpscEAdjXp81RvZvrlzCSjYmz9onFRgltmTl3AINnFh+t9tlW0M9C5zejxBoKFXELv8ljPYAdz2oe+pDWPhWsfvVFYg2VCjpViPM38EakyE5mhk4TDOnUd+w4TeU1hyhZTWyYs=
+PublicExponent: AQAB
+PrivateExponent: UfCoIQ/Z38l8vB6SSqOI/feGjHEl/fxIPX4euKf0D/32k30fHbSaNFrFOuIFmWMB3LimWVEs6u3dpbB9CQeCVg7hwU5puG7OtuiZJgDAhNeOnxvo5btp4XzPZrJSxR4WNQnwIiYWbl0aFlL1VGgHC/3By89ENZyWaZcMLW4KGWE=
+Prime1: yxwC6ogAu8aVcDx2wg1V0b5M5P6jP8qkRFVMxWNTw60Vkn+ECvw6YAZZBHZPaMyRYZLzPgUlyYRd0cjupy4+fQ==
+Prime2: xA1bF8M0RTIQ6+A11AoVG6GIR/aPGg5sogRkIZ7ID/sF6g9HMVU/CM2TqVEBJLRPp73cv6ZeC3bcqOCqZhz+pw==
+Exponent1: xzkblyZ96bGYxTVZm2/vHMOXswod4KWIyMoOepK6B/ZPcZoIT6omLCgtypWtwHLfqyCz3MK51Nc0G2EGzg8rFQ==
+Exponent2: Pu5+mCEb7T5F+kFNZhQadHUklt0JUHbi3hsEvVoHpEGSw3BGDQrtIflDde0/rbWHgDPM4WQY+hscd8UuTXrvLw==
+Coefficient: UuRoNqe7YHnKmQzE6iDWKTMIWTuoqqrFAmXPmKQnC+Y+BQzOVEHUo9bXdDnoI9hzXP1gf8zENMYwYLeWpuYlFQ==
+`
+	privkey, err := pubkey.(*DNSKEY).ReadPrivateKey(strings.NewReader(privStr),
+		"Kmiek.nl.+010+05240.private")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if pubkey.(*DNSKEY).PublicKey != "AwEAAZuMCu2FdugHkTrXYgl5qixvcDw1aDDlvL46/xJKbHBAHY16fNUb2b65cwko2Js/aJxUYJbZk5dwCDZxYfrfbZVtDPQuc3o8QaChVxC7/JYz2AHc9qHvqQ1j4VrH71RWINlQo6VYjzN/BGpMhOZoZOEwzp1HfsOE3lNYcoWU1smL" {
+		t.Error("pubkey is not what we've read")
+	}
+	if pubkey.(*DNSKEY).PrivateKeyString(privkey) != privStr {
+		t.Error("privkey is not what we've read")
+		t.Errorf("%v", pubkey.(*DNSKEY).PrivateKeyString(privkey))
+	}
+}
+
+func TestTag(t *testing.T) {
+	key := new(DNSKEY)
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 3600
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	key.PublicKey = "AwEAAcNEU67LJI5GEgF9QLNqLO1SMq1EdoQ6E9f85ha0k0ewQGCblyW2836GiVsm6k8Kr5ECIoMJ6fZWf3CQSQ9ycWfTyOHfmI3eQ/1Covhb2y4bAmL/07PhrL7ozWBW3wBfM335Ft9xjtXHPy7ztCbV9qZ4TVDTW/Iyg0PiwgoXVesz"
+
+	tag := key.KeyTag()
+	if tag != 12051 {
+		t.Errorf("wrong key tag: %d for key %v", tag, key)
+	}
+}
+
+func TestKeyRSA(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+	key := new(DNSKEY)
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 3600
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	priv, _ := key.Generate(2048)
+
+	soa := new(SOA)
+	soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}
+	soa.Ns = "open.nlnetlabs.nl."
+	soa.Mbox = "miekg.atoom.net."
+	soa.Serial = 1293945905
+	soa.Refresh = 14400
+	soa.Retry = 3600
+	soa.Expire = 604800
+	soa.Minttl = 86400
+
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.TypeCovered = TypeSOA
+	sig.Algorithm = RSASHA256
+	sig.Labels = 2
+	sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
+	sig.Inception = 1293942305  // date -u '+%s' -d"2011-01-02 04:25:05"
+	sig.OrigTtl = soa.Hdr.Ttl
+	sig.KeyTag = key.KeyTag()
+	sig.SignerName = key.Hdr.Name
+
+	if err := sig.Sign(priv.(*rsa.PrivateKey), []RR{soa}); err != nil {
+		t.Error("failed to sign")
+		return
+	}
+	if err := sig.Verify(key, []RR{soa}); err != nil {
+		t.Error("failed to verify")
+	}
+}
+
+func TestKeyToDS(t *testing.T) {
+	key := new(DNSKEY)
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 3600
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = RSASHA256
+	key.PublicKey = "AwEAAcNEU67LJI5GEgF9QLNqLO1SMq1EdoQ6E9f85ha0k0ewQGCblyW2836GiVsm6k8Kr5ECIoMJ6fZWf3CQSQ9ycWfTyOHfmI3eQ/1Covhb2y4bAmL/07PhrL7ozWBW3wBfM335Ft9xjtXHPy7ztCbV9qZ4TVDTW/Iyg0PiwgoXVesz"
+
+	ds := key.ToDS(SHA1)
+	if strings.ToUpper(ds.Digest) != "B5121BDB5B8D86D0CC5FFAFBAAABE26C3E20BAC1" {
+		t.Errorf("wrong DS digest for SHA1\n%v", ds)
+	}
+}
+
+func TestSignRSA(t *testing.T) {
+	pub := "miek.nl. IN DNSKEY 256 3 5 AwEAAb+8lGNCxJgLS8rYVer6EnHVuIkQDghdjdtewDzU3G5R7PbMbKVRvH2Ma7pQyYceoaqWZQirSj72euPWfPxQnMy9ucCylA+FuH9cSjIcPf4PqJfdupHk9X6EBYjxrCLY4p1/yBwgyBIRJtZtAqM3ceAH2WovEJD6rTtOuHo5AluJ"
+
+	priv := `Private-key-format: v1.3
+Algorithm: 5 (RSASHA1)
+Modulus: v7yUY0LEmAtLythV6voScdW4iRAOCF2N217APNTcblHs9sxspVG8fYxrulDJhx6hqpZlCKtKPvZ649Z8/FCczL25wLKUD4W4f1xKMhw9/g+ol926keT1foQFiPGsItjinX/IHCDIEhEm1m0Cozdx4AfZai8QkPqtO064ejkCW4k=
+PublicExponent: AQAB
+PrivateExponent: YPwEmwjk5HuiROKU4xzHQ6l1hG8Iiha4cKRG3P5W2b66/EN/GUh07ZSf0UiYB67o257jUDVEgwCuPJz776zfApcCB4oGV+YDyEu7Hp/rL8KcSN0la0k2r9scKwxTp4BTJT23zyBFXsV/1wRDK1A5NxsHPDMYi2SoK63Enm/1ptk=
+Prime1: /wjOG+fD0ybNoSRn7nQ79udGeR1b0YhUA5mNjDx/x2fxtIXzygYk0Rhx9QFfDy6LOBvz92gbNQlzCLz3DJt5hw==
+Prime2: wHZsJ8OGhkp5p3mrJFZXMDc2mbYusDVTA+t+iRPdS797Tj0pjvU2HN4vTnTj8KBQp6hmnY7dLp9Y1qserySGbw==
+Exponent1: N0A7FsSRIg+IAN8YPQqlawoTtG1t1OkJ+nWrurPootScApX6iMvn8fyvw3p2k51rv84efnzpWAYiC8SUaQDNxQ==
+Exponent2: SvuYRaGyvo0zemE3oS+WRm2scxR8eiA8WJGeOc+obwOKCcBgeZblXzfdHGcEC1KaOcetOwNW/vwMA46lpLzJNw==
+Coefficient: 8+7ZN/JgByqv0NfULiFKTjtyegUcijRuyij7yNxYbCBneDvZGxJwKNi4YYXWx743pcAj4Oi4Oh86gcmxLs+hGw==
+Created: 20110302104537
+Publish: 20110302104537
+Activate: 20110302104537`
+
+	xk, _ := NewRR(pub)
+	k := xk.(*DNSKEY)
+	p, err := k.NewPrivateKey(priv)
+	if err != nil {
+		t.Error(err)
+	}
+	switch priv := p.(type) {
+	case *rsa.PrivateKey:
+		if 65537 != priv.PublicKey.E {
+			t.Error("exponenent should be 65537")
+		}
+	default:
+		t.Errorf("we should have read an RSA key: %v", priv)
+	}
+	if k.KeyTag() != 37350 {
+		t.Errorf("keytag should be 37350, got %d %v", k.KeyTag(), k)
+	}
+
+	soa := new(SOA)
+	soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}
+	soa.Ns = "open.nlnetlabs.nl."
+	soa.Mbox = "miekg.atoom.net."
+	soa.Serial = 1293945905
+	soa.Refresh = 14400
+	soa.Retry = 3600
+	soa.Expire = 604800
+	soa.Minttl = 86400
+
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
+	sig.Inception = 1293942305  // date -u '+%s' -d"2011-01-02 04:25:05"
+	sig.KeyTag = k.KeyTag()
+	sig.SignerName = k.Hdr.Name
+	sig.Algorithm = k.Algorithm
+
+	sig.Sign(p.(*rsa.PrivateKey), []RR{soa})
+	if sig.Signature != "D5zsobpQcmMmYsUMLxCVEtgAdCvTu8V/IEeP4EyLBjqPJmjt96bwM9kqihsccofA5LIJ7DN91qkCORjWSTwNhzCv7bMyr2o5vBZElrlpnRzlvsFIoAZCD9xg6ZY7ZyzUJmU6IcTwG4v3xEYajcpbJJiyaw/RqR90MuRdKPiBzSo=" {
+		t.Errorf("signature is not correct: %v", sig)
+	}
+}
+
+func TestSignVerifyECDSA(t *testing.T) {
+	pub := `example.net. 3600 IN DNSKEY 257 3 14 (
+	xKYaNhWdGOfJ+nPrL8/arkwf2EY3MDJ+SErKivBVSum1
+	w/egsXvSADtNJhyem5RCOpgQ6K8X1DRSEkrbYQ+OB+v8
+	/uX45NBwY8rp65F6Glur8I/mlVNgF6W/qTI37m40 )`
+	priv := `Private-key-format: v1.2
+Algorithm: 14 (ECDSAP384SHA384)
+PrivateKey: WURgWHCcYIYUPWgeLmiPY2DJJk02vgrmTfitxgqcL4vwW7BOrbawVmVe0d9V94SR`
+
+	eckey, err := NewRR(pub)
+	if err != nil {
+		t.Fatal(err)
+	}
+	privkey, err := eckey.(*DNSKEY).NewPrivateKey(priv)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// TODO: Create separate test for this
+	ds := eckey.(*DNSKEY).ToDS(SHA384)
+	if ds.KeyTag != 10771 {
+		t.Fatal("wrong keytag on DS")
+	}
+	if ds.Digest != "72d7b62976ce06438e9c0bf319013cf801f09ecc84b8d7e9495f27e305c6a9b0563a9b5f4d288405c3008a946df983d6" {
+		t.Fatal("wrong DS Digest")
+	}
+	a, _ := NewRR("www.example.net. 3600 IN A 192.0.2.1")
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"example.net.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.Expiration, _ = StringToTime("20100909102025")
+	sig.Inception, _ = StringToTime("20100812102025")
+	sig.KeyTag = eckey.(*DNSKEY).KeyTag()
+	sig.SignerName = eckey.(*DNSKEY).Hdr.Name
+	sig.Algorithm = eckey.(*DNSKEY).Algorithm
+
+	if sig.Sign(privkey.(*ecdsa.PrivateKey), []RR{a}) != nil {
+		t.Fatal("failure to sign the record")
+	}
+
+	if err := sig.Verify(eckey.(*DNSKEY), []RR{a}); err != nil {
+		t.Fatalf("failure to validate:\n%s\n%s\n%s\n\n%s\n\n%v",
+			eckey.(*DNSKEY).String(),
+			a.String(),
+			sig.String(),
+			eckey.(*DNSKEY).PrivateKeyString(privkey),
+			err,
+		)
+	}
+}
+
+func TestSignVerifyECDSA2(t *testing.T) {
+	srv1, err := NewRR("srv.miek.nl. IN SRV 1000 800 0 web1.miek.nl.")
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv := srv1.(*SRV)
+
+	// With this key
+	key := new(DNSKEY)
+	key.Hdr.Rrtype = TypeDNSKEY
+	key.Hdr.Name = "miek.nl."
+	key.Hdr.Class = ClassINET
+	key.Hdr.Ttl = 14400
+	key.Flags = 256
+	key.Protocol = 3
+	key.Algorithm = ECDSAP256SHA256
+	privkey, err := key.Generate(256)
+	if err != nil {
+		t.Fatal("failure to generate key")
+	}
+
+	// Fill in the values of the Sig, before signing
+	sig := new(RRSIG)
+	sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
+	sig.TypeCovered = srv.Hdr.Rrtype
+	sig.Labels = uint8(CountLabel(srv.Hdr.Name)) // works for all 3
+	sig.OrigTtl = srv.Hdr.Ttl
+	sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
+	sig.Inception = 1293942305  // date -u '+%s' -d"2011-01-02 04:25:05"
+	sig.KeyTag = key.KeyTag()   // Get the keyfrom the Key
+	sig.SignerName = key.Hdr.Name
+	sig.Algorithm = ECDSAP256SHA256
+
+	if sig.Sign(privkey.(*ecdsa.PrivateKey), []RR{srv}) != nil {
+		t.Fatal("failure to sign the record")
+	}
+
+	err = sig.Verify(key, []RR{srv})
+	if err != nil {
+		t.Logf("failure to validate:\n%s\n%s\n%s\n\n%s\n\n%v",
+			key.String(),
+			srv.String(),
+			sig.String(),
+			key.PrivateKeyString(privkey),
+			err,
+		)
+	}
+}
+
+// Here the test vectors from the relevant RFCs are checked.
+// rfc6605 6.1
+func TestRFC6605P256(t *testing.T) {
+	exDNSKEY := `example.net. 3600 IN DNSKEY 257 3 13 (
+                 GojIhhXUN/u4v54ZQqGSnyhWJwaubCvTmeexv7bR6edb
+                 krSqQpF64cYbcB7wNcP+e+MAnLr+Wi9xMWyQLc8NAA== )`
+	exPriv := `Private-key-format: v1.2
+Algorithm: 13 (ECDSAP256SHA256)
+PrivateKey: GU6SnQ/Ou+xC5RumuIUIuJZteXT2z0O/ok1s38Et6mQ=`
+	rrDNSKEY, err := NewRR(exDNSKEY)
+	if err != nil {
+		t.Fatal(err)
+	}
+	priv, err := rrDNSKEY.(*DNSKEY).NewPrivateKey(exPriv)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	exDS := `example.net. 3600 IN DS 55648 13 2 (
+             b4c8c1fe2e7477127b27115656ad6256f424625bf5c1
+             e2770ce6d6e37df61d17 )`
+	rrDS, err := NewRR(exDS)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ourDS := rrDNSKEY.(*DNSKEY).ToDS(SHA256)
+	if !reflect.DeepEqual(ourDS, rrDS.(*DS)) {
+		t.Errorf("DS record differs:\n%v\n%v", ourDS, rrDS.(*DS))
+	}
+
+	exA := `www.example.net. 3600 IN A 192.0.2.1`
+	exRRSIG := `www.example.net. 3600 IN RRSIG A 13 3 3600 (
+                20100909100439 20100812100439 55648 example.net.
+                qx6wLYqmh+l9oCKTN6qIc+bw6ya+KJ8oMz0YP107epXA
+                yGmt+3SNruPFKG7tZoLBLlUzGGus7ZwmwWep666VCw== )`
+	rrA, err := NewRR(exA)
+	if err != nil {
+		t.Fatal(err)
+	}
+	rrRRSIG, err := NewRR(exRRSIG)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = rrRRSIG.(*RRSIG).Verify(rrDNSKEY.(*DNSKEY), []RR{rrA}); err != nil {
+		t.Errorf("failure to validate the spec RRSIG: %v", err)
+	}
+
+	ourRRSIG := &RRSIG{
+		Hdr: RR_Header{
+			Ttl: rrA.Header().Ttl,
+		},
+		KeyTag:     rrDNSKEY.(*DNSKEY).KeyTag(),
+		SignerName: rrDNSKEY.(*DNSKEY).Hdr.Name,
+		Algorithm:  rrDNSKEY.(*DNSKEY).Algorithm,
+	}
+	ourRRSIG.Expiration, _ = StringToTime("20100909100439")
+	ourRRSIG.Inception, _ = StringToTime("20100812100439")
+	err = ourRRSIG.Sign(priv.(*ecdsa.PrivateKey), []RR{rrA})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err = ourRRSIG.Verify(rrDNSKEY.(*DNSKEY), []RR{rrA}); err != nil {
+		t.Errorf("failure to validate our RRSIG: %v", err)
+	}
+
+	// Signatures are randomized
+	rrRRSIG.(*RRSIG).Signature = ""
+	ourRRSIG.Signature = ""
+	if !reflect.DeepEqual(ourRRSIG, rrRRSIG.(*RRSIG)) {
+		t.Fatalf("RRSIG record differs:\n%v\n%v", ourRRSIG, rrRRSIG.(*RRSIG))
+	}
+}
+
+// rfc6605 6.2
+func TestRFC6605P384(t *testing.T) {
+	exDNSKEY := `example.net. 3600 IN DNSKEY 257 3 14 (
+                 xKYaNhWdGOfJ+nPrL8/arkwf2EY3MDJ+SErKivBVSum1
+                 w/egsXvSADtNJhyem5RCOpgQ6K8X1DRSEkrbYQ+OB+v8
+                 /uX45NBwY8rp65F6Glur8I/mlVNgF6W/qTI37m40 )`
+	exPriv := `Private-key-format: v1.2
+Algorithm: 14 (ECDSAP384SHA384)
+PrivateKey: WURgWHCcYIYUPWgeLmiPY2DJJk02vgrmTfitxgqcL4vwW7BOrbawVmVe0d9V94SR`
+	rrDNSKEY, err := NewRR(exDNSKEY)
+	if err != nil {
+		t.Fatal(err)
+	}
+	priv, err := rrDNSKEY.(*DNSKEY).NewPrivateKey(exPriv)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	exDS := `example.net. 3600 IN DS 10771 14 4 (
+           72d7b62976ce06438e9c0bf319013cf801f09ecc84b8
+           d7e9495f27e305c6a9b0563a9b5f4d288405c3008a94
+           6df983d6 )`
+	rrDS, err := NewRR(exDS)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ourDS := rrDNSKEY.(*DNSKEY).ToDS(SHA384)
+	if !reflect.DeepEqual(ourDS, rrDS.(*DS)) {
+		t.Fatalf("DS record differs:\n%v\n%v", ourDS, rrDS.(*DS))
+	}
+
+	exA := `www.example.net. 3600 IN A 192.0.2.1`
+	exRRSIG := `www.example.net. 3600 IN RRSIG A 14 3 3600 (
+           20100909102025 20100812102025 10771 example.net.
+           /L5hDKIvGDyI1fcARX3z65qrmPsVz73QD1Mr5CEqOiLP
+           95hxQouuroGCeZOvzFaxsT8Glr74hbavRKayJNuydCuz
+           WTSSPdz7wnqXL5bdcJzusdnI0RSMROxxwGipWcJm )`
+	rrA, err := NewRR(exA)
+	if err != nil {
+		t.Fatal(err)
+	}
+	rrRRSIG, err := NewRR(exRRSIG)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = rrRRSIG.(*RRSIG).Verify(rrDNSKEY.(*DNSKEY), []RR{rrA}); err != nil {
+		t.Errorf("failure to validate the spec RRSIG: %v", err)
+	}
+
+	ourRRSIG := &RRSIG{
+		Hdr: RR_Header{
+			Ttl: rrA.Header().Ttl,
+		},
+		KeyTag:     rrDNSKEY.(*DNSKEY).KeyTag(),
+		SignerName: rrDNSKEY.(*DNSKEY).Hdr.Name,
+		Algorithm:  rrDNSKEY.(*DNSKEY).Algorithm,
+	}
+	ourRRSIG.Expiration, _ = StringToTime("20100909102025")
+	ourRRSIG.Inception, _ = StringToTime("20100812102025")
+	err = ourRRSIG.Sign(priv.(*ecdsa.PrivateKey), []RR{rrA})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err = ourRRSIG.Verify(rrDNSKEY.(*DNSKEY), []RR{rrA}); err != nil {
+		t.Errorf("failure to validate our RRSIG: %v", err)
+	}
+
+	// Signatures are randomized
+	rrRRSIG.(*RRSIG).Signature = ""
+	ourRRSIG.Signature = ""
+	if !reflect.DeepEqual(ourRRSIG, rrRRSIG.(*RRSIG)) {
+		t.Fatalf("RRSIG record differs:\n%v\n%v", ourRRSIG, rrRRSIG.(*RRSIG))
+	}
+}
+
+func TestInvalidRRSet(t *testing.T) {
+	goodRecords := make([]RR, 2)
+	goodRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	goodRecords[1] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"_o/"}}
+
+	// Generate key
+	keyname := "cloudflare.com."
+	key := &DNSKEY{
+		Hdr:       RR_Header{Name: keyname, Rrtype: TypeDNSKEY, Class: ClassINET, Ttl: 0},
+		Algorithm: ECDSAP256SHA256,
+		Flags:     ZONE,
+		Protocol:  3,
+	}
+	privatekey, err := key.Generate(256)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	// Need to fill in: Inception, Expiration, KeyTag, SignerName and Algorithm
+	curTime := time.Now()
+	signature := &RRSIG{
+		Inception:  uint32(curTime.Unix()),
+		Expiration: uint32(curTime.Add(time.Hour).Unix()),
+		KeyTag:     key.KeyTag(),
+		SignerName: keyname,
+		Algorithm:  ECDSAP256SHA256,
+	}
+
+	// Inconsistent name between records
+	badRecords := make([]RR, 2)
+	badRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	badRecords[1] = &TXT{Hdr: RR_Header{Name: "nama.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"_o/"}}
+
+	if IsRRset(badRecords) {
+		t.Fatal("Record set with inconsistent names considered valid")
+	}
+
+	badRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	badRecords[1] = &A{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeA, Class: ClassINET, Ttl: 0}}
+
+	if IsRRset(badRecords) {
+		t.Fatal("Record set with inconsistent record types considered valid")
+	}
+
+	badRecords[0] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	badRecords[1] = &TXT{Hdr: RR_Header{Name: "name.cloudflare.com.", Rrtype: TypeTXT, Class: ClassCHAOS, Ttl: 0}, Txt: []string{"_o/"}}
+
+	if IsRRset(badRecords) {
+		t.Fatal("Record set with inconsistent record class considered valid")
+	}
+
+	// Sign the good record set and then make sure verification fails on the bad record set
+	if err := signature.Sign(privatekey.(crypto.Signer), goodRecords); err != nil {
+		t.Fatal("Signing good records failed")
+	}
+
+	if err := signature.Verify(key, badRecords); err != ErrRRset {
+		t.Fatal("Verification did not return ErrRRset with inconsistent records")
+	}
+}

doc.go

@@ -0,0 +1,251 @@
+/*
+Package dns implements a full featured interface to the Domain Name System.
+Server- and client-side programming is supported.
+The package allows complete control over what is send out to the DNS. The package
+API follows the less-is-more principle, by presenting a small, clean interface.
+
+The package dns supports (asynchronous) querying/replying, incoming/outgoing zone transfers,
+TSIG, EDNS0, dynamic updates, notifies and DNSSEC validation/signing.
+Note that domain names MUST be fully qualified, before sending them, unqualified
+names in a message will result in a packing failure.
+
+Resource records are native types. They are not stored in wire format.
+Basic usage pattern for creating a new resource record:
+
+     r := new(dns.MX)
+     r.Hdr = dns.RR_Header{Name: "miek.nl.", Rrtype: dns.TypeMX,
+	Class: dns.ClassINET, Ttl: 3600}
+     r.Preference = 10
+     r.Mx = "mx.miek.nl."
+
+Or directly from a string:
+
+     mx, err := dns.NewRR("miek.nl. 3600 IN MX 10 mx.miek.nl.")
+
+Or when the default TTL (3600) and class (IN) suit you:
+
+     mx, err := dns.NewRR("miek.nl. MX 10 mx.miek.nl.")
+
+Or even:
+
+     mx, err := dns.NewRR("$ORIGIN nl.\nmiek 1H IN MX 10 mx.miek")
+
+In the DNS messages are exchanged, these messages contain resource
+records (sets).  Use pattern for creating a message:
+
+     m := new(dns.Msg)
+     m.SetQuestion("miek.nl.", dns.TypeMX)
+
+Or when not certain if the domain name is fully qualified:
+
+	m.SetQuestion(dns.Fqdn("miek.nl"), dns.TypeMX)
+
+The message m is now a message with the question section set to ask
+the MX records for the miek.nl. zone.
+
+The following is slightly more verbose, but more flexible:
+
+     m1 := new(dns.Msg)
+     m1.Id = dns.Id()
+     m1.RecursionDesired = true
+     m1.Question = make([]dns.Question, 1)
+     m1.Question[0] = dns.Question{"miek.nl.", dns.TypeMX, dns.ClassINET}
+
+After creating a message it can be send.
+Basic use pattern for synchronous querying the DNS at a
+server configured on 127.0.0.1 and port 53:
+
+     c := new(dns.Client)
+     in, rtt, err := c.Exchange(m1, "127.0.0.1:53")
+
+Suppressing multiple outstanding queries (with the same question, type and
+class) is as easy as setting:
+
+	c.SingleInflight = true
+
+If these "advanced" features are not needed, a simple UDP query can be send,
+with:
+
+	in, err := dns.Exchange(m1, "127.0.0.1:53")
+
+When this functions returns you will get dns message. A dns message consists
+out of four sections.
+The question section: in.Question, the answer section: in.Answer,
+the authority section: in.Ns and the additional section: in.Extra.
+
+Each of these sections (except the Question section) contain a []RR. Basic
+use pattern for accessing the rdata of a TXT RR as the first RR in
+the Answer section:
+
+	if t, ok := in.Answer[0].(*dns.TXT); ok {
+		// do something with t.Txt
+	}
+
+Domain Name and TXT Character String Representations
+
+Both domain names and TXT character strings are converted to presentation
+form both when unpacked and when converted to strings.
+
+For TXT character strings, tabs, carriage returns and line feeds will be
+converted to \t, \r and \n respectively. Back slashes and quotations marks
+will be escaped. Bytes below 32 and above 127 will be converted to \DDD
+form.
+
+For domain names, in addition to the above rules brackets, periods,
+spaces, semicolons and the at symbol are escaped.
+
+DNSSEC
+
+DNSSEC (DNS Security Extension) adds a layer of security to the DNS. It
+uses public key cryptography to sign resource records. The
+public keys are stored in DNSKEY records and the signatures in RRSIG records.
+
+Requesting DNSSEC information for a zone is done by adding the DO (DNSSEC OK) bit
+to an request.
+
+     m := new(dns.Msg)
+     m.SetEdns0(4096, true)
+
+Signature generation, signature verification and key generation are all supported.
+
+DYNAMIC UPDATES
+
+Dynamic updates reuses the DNS message format, but renames three of
+the sections. Question is Zone, Answer is Prerequisite, Authority is
+Update, only the Additional is not renamed. See RFC 2136 for the gory details.
+
+You can set a rather complex set of rules for the existence of absence of
+certain resource records or names in a zone to specify if resource records
+should be added or removed. The table from RFC 2136 supplemented with the Go
+DNS function shows which functions exist to specify the prerequisites.
+
+ 3.2.4 - Table Of Metavalues Used In Prerequisite Section
+
+  CLASS    TYPE     RDATA    Meaning                    Function
+  --------------------------------------------------------------
+  ANY      ANY      empty    Name is in use             dns.NameUsed
+  ANY      rrset    empty    RRset exists (value indep) dns.RRsetUsed
+  NONE     ANY      empty    Name is not in use         dns.NameNotUsed
+  NONE     rrset    empty    RRset does not exist       dns.RRsetNotUsed
+  zone     rrset    rr       RRset exists (value dep)   dns.Used
+
+The prerequisite section can also be left empty.
+If you have decided on the prerequisites you can tell what RRs should
+be added or deleted. The next table shows the options you have and
+what functions to call.
+
+ 3.4.2.6 - Table Of Metavalues Used In Update Section
+
+  CLASS    TYPE     RDATA    Meaning                     Function
+  ---------------------------------------------------------------
+  ANY      ANY      empty    Delete all RRsets from name dns.RemoveName
+  ANY      rrset    empty    Delete an RRset             dns.RemoveRRset
+  NONE     rrset    rr       Delete an RR from RRset     dns.Remove
+  zone     rrset    rr       Add to an RRset             dns.Insert
+
+TRANSACTION SIGNATURE
+
+An TSIG or transaction signature adds a HMAC TSIG record to each message sent.
+The supported algorithms include: HmacMD5, HmacSHA1, HmacSHA256 and HmacSHA512.
+
+Basic use pattern when querying with a TSIG name "axfr." (note that these key names
+must be fully qualified - as they are domain names) and the base64 secret
+"so6ZGir4GPAqINNh9U5c3A==":
+
+	c := new(dns.Client)
+	c.TsigSecret = map[string]string{"axfr.": "so6ZGir4GPAqINNh9U5c3A=="}
+	m := new(dns.Msg)
+	m.SetQuestion("miek.nl.", dns.TypeMX)
+	m.SetTsig("axfr.", dns.HmacMD5, 300, time.Now().Unix())
+	...
+	// When sending the TSIG RR is calculated and filled in before sending
+
+When requesting an zone transfer (almost all TSIG usage is when requesting zone transfers), with
+TSIG, this is the basic use pattern. In this example we request an AXFR for
+miek.nl. with TSIG key named "axfr." and secret "so6ZGir4GPAqINNh9U5c3A=="
+and using the server 176.58.119.54:
+
+	t := new(dns.Transfer)
+	m := new(dns.Msg)
+	t.TsigSecret = map[string]string{"axfr.": "so6ZGir4GPAqINNh9U5c3A=="}
+	m.SetAxfr("miek.nl.")
+	m.SetTsig("axfr.", dns.HmacMD5, 300, time.Now().Unix())
+	c, err := t.In(m, "176.58.119.54:53")
+	for r := range c { ... }
+
+You can now read the records from the transfer as they come in. Each envelope is checked with TSIG.
+If something is not correct an error is returned.
+
+Basic use pattern validating and replying to a message that has TSIG set.
+
+	server := &dns.Server{Addr: ":53", Net: "udp"}
+	server.TsigSecret = map[string]string{"axfr.": "so6ZGir4GPAqINNh9U5c3A=="}
+	go server.ListenAndServe()
+	dns.HandleFunc(".", handleRequest)
+
+	func handleRequest(w dns.ResponseWriter, r *dns.Msg) {
+		m := new(dns.Msg)
+		m.SetReply(r)
+		if r.IsTsig() != nil {
+			if w.TsigStatus() == nil {
+				// *Msg r has an TSIG record and it was validated
+				m.SetTsig("axfr.", dns.HmacMD5, 300, time.Now().Unix())
+			} else {
+				// *Msg r has an TSIG records and it was not valided
+			}
+		}
+		w.WriteMsg(m)
+	}
+
+PRIVATE RRS
+
+RFC 6895 sets aside a range of type codes for private use. This range
+is 65,280 - 65,534 (0xFF00 - 0xFFFE). When experimenting with new Resource Records these
+can be used, before requesting an official type code from IANA.
+
+see http://miek.nl/posts/2014/Sep/21/Private%20RRs%20and%20IDN%20in%20Go%20DNS/ for more
+information.
+
+EDNS0
+
+EDNS0 is an extension mechanism for the DNS defined in RFC 2671 and updated
+by RFC 6891. It defines an new RR type, the OPT RR, which is then completely
+abused.
+Basic use pattern for creating an (empty) OPT RR:
+
+	o := new(dns.OPT)
+	o.Hdr.Name = "." // MUST be the root zone, per definition.
+	o.Hdr.Rrtype = dns.TypeOPT
+
+The rdata of an OPT RR consists out of a slice of EDNS0 (RFC 6891)
+interfaces. Currently only a few have been standardized: EDNS0_NSID
+(RFC 5001) and EDNS0_SUBNET (draft-vandergaast-edns-client-subnet-02). Note
+that these options may be combined in an OPT RR.
+Basic use pattern for a server to check if (and which) options are set:
+
+	// o is a dns.OPT
+	for _, s := range o.Option {
+		switch e := s.(type) {
+		case *dns.EDNS0_NSID:
+			// do stuff with e.Nsid
+		case *dns.EDNS0_SUBNET:
+			// access e.Family, e.Address, etc.
+		}
+	}
+
+SIG(0)
+
+From RFC 2931:
+
+    SIG(0) provides protection for DNS transactions and requests ....
+    ... protection for glue records, DNS requests, protection for message headers
+    on requests and responses, and protection of the overall integrity of a response.
+
+It works like TSIG, except that SIG(0) uses public key cryptography, instead of the shared
+secret approach in TSIG.
+Supported algorithms: DSA, ECDSAP256SHA256, ECDSAP384SHA384, RSASHA1, RSASHA256 and
+RSASHA512.
+
+Signing subsequent messages in multi-message sessions is not implemented.
+*/
+package dns

dyn_test.go

@@ -0,0 +1,3 @@
+package dns
+
+// Find better solution

edns.go

@@ -0,0 +1,505 @@
+package dns
+
+import (
+	"encoding/hex"
+	"errors"
+	"net"
+	"strconv"
+)
+
+// EDNS0 Option codes.
+const (
+	EDNS0LLQ         = 0x1     // long lived queries: http://tools.ietf.org/html/draft-sekar-dns-llq-01
+	EDNS0UL          = 0x2     // update lease draft: http://files.dns-sd.org/draft-sekar-dns-ul.txt
+	EDNS0NSID        = 0x3     // nsid (RFC5001)
+	EDNS0DAU         = 0x5     // DNSSEC Algorithm Understood
+	EDNS0DHU         = 0x6     // DS Hash Understood
+	EDNS0N3U         = 0x7     // NSEC3 Hash Understood
+	EDNS0SUBNET      = 0x8     // client-subnet (RFC6891)
+	EDNS0EXPIRE      = 0x9     // EDNS0 expire
+	EDNS0SUBNETDRAFT = 0x50fa  // Don't use! Use EDNS0SUBNET
+	EDNS0LOCALSTART  = 0xFDE9  // Beginning of range reserved for local/experimental use (RFC6891)
+	EDNS0LOCALEND    = 0xFFFE  // End of range reserved for local/experimental use (RFC6891)
+	_DO              = 1 << 15 // dnssec ok
+)
+
+// OPT is the EDNS0 RR appended to messages to convey extra (meta) information.
+// See RFC 6891.
+type OPT struct {
+	Hdr    RR_Header
+	Option []EDNS0 `dns:"opt"`
+}
+
+func (rr *OPT) String() string {
+	s := "\n;; OPT PSEUDOSECTION:\n; EDNS: version " + strconv.Itoa(int(rr.Version())) + "; "
+	if rr.Do() {
+		s += "flags: do; "
+	} else {
+		s += "flags: ; "
+	}
+	s += "udp: " + strconv.Itoa(int(rr.UDPSize()))
+
+	for _, o := range rr.Option {
+		switch o.(type) {
+		case *EDNS0_NSID:
+			s += "\n; NSID: " + o.String()
+			h, e := o.pack()
+			var r string
+			if e == nil {
+				for _, c := range h {
+					r += "(" + string(c) + ")"
+				}
+				s += "  " + r
+			}
+		case *EDNS0_SUBNET:
+			s += "\n; SUBNET: " + o.String()
+			if o.(*EDNS0_SUBNET).DraftOption {
+				s += " (draft)"
+			}
+		case *EDNS0_UL:
+			s += "\n; UPDATE LEASE: " + o.String()
+		case *EDNS0_LLQ:
+			s += "\n; LONG LIVED QUERIES: " + o.String()
+		case *EDNS0_DAU:
+			s += "\n; DNSSEC ALGORITHM UNDERSTOOD: " + o.String()
+		case *EDNS0_DHU:
+			s += "\n; DS HASH UNDERSTOOD: " + o.String()
+		case *EDNS0_N3U:
+			s += "\n; NSEC3 HASH UNDERSTOOD: " + o.String()
+		case *EDNS0_LOCAL:
+			s += "\n; LOCAL OPT: " + o.String()
+		}
+	}
+	return s
+}
+
+func (rr *OPT) len() int {
+	l := rr.Hdr.len()
+	for i := 0; i < len(rr.Option); i++ {
+		l += 4 // Account for 2-byte option code and 2-byte option length.
+		lo, _ := rr.Option[i].pack()
+		l += len(lo)
+	}
+	return l
+}
+
+// return the old value -> delete SetVersion?
+
+// Version returns the EDNS version used. Only zero is defined.
+func (rr *OPT) Version() uint8 {
+	return uint8((rr.Hdr.Ttl & 0x00FF0000) >> 16)
+}
+
+// SetVersion sets the version of EDNS. This is usually zero.
+func (rr *OPT) SetVersion(v uint8) {
+	rr.Hdr.Ttl = rr.Hdr.Ttl&0xFF00FFFF | (uint32(v) << 16)
+}
+
+// ExtendedRcode returns the EDNS extended RCODE field (the upper 8 bits of the TTL).
+func (rr *OPT) ExtendedRcode() uint8 {
+	return uint8((rr.Hdr.Ttl & 0xFF000000) >> 24)
+}
+
+// SetExtendedRcode sets the EDNS extended RCODE field.
+func (rr *OPT) SetExtendedRcode(v uint8) {
+	rr.Hdr.Ttl = rr.Hdr.Ttl&0x00FFFFFF | (uint32(v) << 24)
+}
+
+// UDPSize returns the UDP buffer size.
+func (rr *OPT) UDPSize() uint16 {
+	return rr.Hdr.Class
+}
+
+// SetUDPSize sets the UDP buffer size.
+func (rr *OPT) SetUDPSize(size uint16) {
+	rr.Hdr.Class = size
+}
+
+// Do returns the value of the DO (DNSSEC OK) bit.
+func (rr *OPT) Do() bool {
+	return rr.Hdr.Ttl&_DO == _DO
+}
+
+// SetDo sets the DO (DNSSEC OK) bit.
+func (rr *OPT) SetDo() {
+	rr.Hdr.Ttl |= _DO
+}
+
+// EDNS0 defines an EDNS0 Option. An OPT RR can have multiple options appended to
+// it.
+type EDNS0 interface {
+	// Option returns the option code for the option.
+	Option() uint16
+	// pack returns the bytes of the option data.
+	pack() ([]byte, error)
+	// unpack sets the data as found in the buffer. Is also sets
+	// the length of the slice as the length of the option data.
+	unpack([]byte) error
+	// String returns the string representation of the option.
+	String() string
+}
+
+// The nsid EDNS0 option is used to retrieve a nameserver
+// identifier. When sending a request Nsid must be set to the empty string
+// The identifier is an opaque string encoded as hex.
+// Basic use pattern for creating an nsid option:
+//
+//	o := new(dns.OPT)
+//	o.Hdr.Name = "."
+//	o.Hdr.Rrtype = dns.TypeOPT
+//	e := new(dns.EDNS0_NSID)
+//	e.Code = dns.EDNS0NSID
+//	e.Nsid = "AA"
+//	o.Option = append(o.Option, e)
+type EDNS0_NSID struct {
+	Code uint16 // Always EDNS0NSID
+	Nsid string // This string needs to be hex encoded
+}
+
+func (e *EDNS0_NSID) pack() ([]byte, error) {
+	h, err := hex.DecodeString(e.Nsid)
+	if err != nil {
+		return nil, err
+	}
+	return h, nil
+}
+
+func (e *EDNS0_NSID) Option() uint16        { return EDNS0NSID }
+func (e *EDNS0_NSID) unpack(b []byte) error { e.Nsid = hex.EncodeToString(b); return nil }
+func (e *EDNS0_NSID) String() string        { return string(e.Nsid) }
+
+// EDNS0_SUBNET is the subnet option that is used to give the remote nameserver
+// an idea of where the client lives. It can then give back a different
+// answer depending on the location or network topology.
+// Basic use pattern for creating an subnet option:
+//
+//	o := new(dns.OPT)
+//	o.Hdr.Name = "."
+//	o.Hdr.Rrtype = dns.TypeOPT
+//	e := new(dns.EDNS0_SUBNET)
+//	e.Code = dns.EDNS0SUBNET
+//	e.Family = 1	// 1 for IPv4 source address, 2 for IPv6
+//	e.NetMask = 32	// 32 for IPV4, 128 for IPv6
+//	e.SourceScope = 0
+//	e.Address = net.ParseIP("127.0.0.1").To4()	// for IPv4
+//	// e.Address = net.ParseIP("2001:7b8:32a::2")	// for IPV6
+//	o.Option = append(o.Option, e)
+//
+// Note: the spec (draft-ietf-dnsop-edns-client-subnet-00) has some insane logic
+// for which netmask applies to the address. This code will parse all the
+// available bits when unpacking (up to optlen). When packing it will apply
+// SourceNetmask. If you need more advanced logic, patches welcome and good luck.
+type EDNS0_SUBNET struct {
+	Code          uint16 // Always EDNS0SUBNET
+	Family        uint16 // 1 for IP, 2 for IP6
+	SourceNetmask uint8
+	SourceScope   uint8
+	Address       net.IP
+	DraftOption   bool // Set to true if using the old (0x50fa) option code
+}
+
+func (e *EDNS0_SUBNET) Option() uint16 {
+	if e.DraftOption {
+		return EDNS0SUBNETDRAFT
+	}
+	return EDNS0SUBNET
+}
+
+func (e *EDNS0_SUBNET) pack() ([]byte, error) {
+	b := make([]byte, 4)
+	b[0], b[1] = packUint16(e.Family)
+	b[2] = e.SourceNetmask
+	b[3] = e.SourceScope
+	switch e.Family {
+	case 1:
+		if e.SourceNetmask > net.IPv4len*8 {
+			return nil, errors.New("dns: bad netmask")
+		}
+		if len(e.Address.To4()) != net.IPv4len {
+			return nil, errors.New("dns: bad address")
+		}
+		ip := e.Address.To4().Mask(net.CIDRMask(int(e.SourceNetmask), net.IPv4len*8))
+		needLength := (e.SourceNetmask + 8 - 1) / 8 // division rounding up
+		b = append(b, ip[:needLength]...)
+	case 2:
+		if e.SourceNetmask > net.IPv6len*8 {
+			return nil, errors.New("dns: bad netmask")
+		}
+		if len(e.Address) != net.IPv6len {
+			return nil, errors.New("dns: bad address")
+		}
+		ip := e.Address.Mask(net.CIDRMask(int(e.SourceNetmask), net.IPv6len*8))
+		needLength := (e.SourceNetmask + 8 - 1) / 8 // division rounding up
+		b = append(b, ip[:needLength]...)
+	default:
+		return nil, errors.New("dns: bad address family")
+	}
+	return b, nil
+}
+
+func (e *EDNS0_SUBNET) unpack(b []byte) error {
+	if len(b) < 4 {
+		return ErrBuf
+	}
+	e.Family, _ = unpackUint16(b, 0)
+	e.SourceNetmask = b[2]
+	e.SourceScope = b[3]
+	switch e.Family {
+	case 1:
+		if e.SourceNetmask > net.IPv4len*8 || e.SourceScope > net.IPv4len*8 {
+			return errors.New("dns: bad netmask")
+		}
+		addr := make([]byte, net.IPv4len)
+		for i := 0; i < net.IPv4len && 4+i < len(b); i++ {
+			addr[i] = b[4+i]
+		}
+		e.Address = net.IPv4(addr[0], addr[1], addr[2], addr[3])
+	case 2:
+		if e.SourceNetmask > net.IPv6len*8 || e.SourceScope > net.IPv6len*8 {
+			return errors.New("dns: bad netmask")
+		}
+		addr := make([]byte, net.IPv6len)
+		for i := 0; i < net.IPv6len && 4+i < len(b); i++ {
+			addr[i] = b[4+i]
+		}
+		e.Address = net.IP{addr[0], addr[1], addr[2], addr[3], addr[4],
+			addr[5], addr[6], addr[7], addr[8], addr[9], addr[10],
+			addr[11], addr[12], addr[13], addr[14], addr[15]}
+	default:
+		return errors.New("dns: bad address family")
+	}
+	return nil
+}
+
+func (e *EDNS0_SUBNET) String() (s string) {
+	if e.Address == nil {
+		s = "<nil>"
+	} else if e.Address.To4() != nil {
+		s = e.Address.String()
+	} else {
+		s = "[" + e.Address.String() + "]"
+	}
+	s += "/" + strconv.Itoa(int(e.SourceNetmask)) + "/" + strconv.Itoa(int(e.SourceScope))
+	return
+}
+
+// The EDNS0_UL (Update Lease) (draft RFC) option is used to tell the server to set
+// an expiration on an update RR. This is helpful for clients that cannot clean
+// up after themselves. This is a draft RFC and more information can be found at
+// http://files.dns-sd.org/draft-sekar-dns-ul.txt
+//
+//	o := new(dns.OPT)
+//	o.Hdr.Name = "."
+//	o.Hdr.Rrtype = dns.TypeOPT
+//	e := new(dns.EDNS0_UL)
+//	e.Code = dns.EDNS0UL
+//	e.Lease = 120 // in seconds
+//	o.Option = append(o.Option, e)
+type EDNS0_UL struct {
+	Code  uint16 // Always EDNS0UL
+	Lease uint32
+}
+
+func (e *EDNS0_UL) Option() uint16 { return EDNS0UL }
+func (e *EDNS0_UL) String() string { return strconv.FormatUint(uint64(e.Lease), 10) }
+
+// Copied: http://golang.org/src/pkg/net/dnsmsg.go
+func (e *EDNS0_UL) pack() ([]byte, error) {
+	b := make([]byte, 4)
+	b[0] = byte(e.Lease >> 24)
+	b[1] = byte(e.Lease >> 16)
+	b[2] = byte(e.Lease >> 8)
+	b[3] = byte(e.Lease)
+	return b, nil
+}
+
+func (e *EDNS0_UL) unpack(b []byte) error {
+	if len(b) < 4 {
+		return ErrBuf
+	}
+	e.Lease = uint32(b[0])<<24 | uint32(b[1])<<16 | uint32(b[2])<<8 | uint32(b[3])
+	return nil
+}
+
+// EDNS0_LLQ stands for Long Lived Queries: http://tools.ietf.org/html/draft-sekar-dns-llq-01
+// Implemented for completeness, as the EDNS0 type code is assigned.
+type EDNS0_LLQ struct {
+	Code      uint16 // Always EDNS0LLQ
+	Version   uint16
+	Opcode    uint16
+	Error     uint16
+	Id        uint64
+	LeaseLife uint32
+}
+
+func (e *EDNS0_LLQ) Option() uint16 { return EDNS0LLQ }
+
+func (e *EDNS0_LLQ) pack() ([]byte, error) {
+	b := make([]byte, 18)
+	b[0], b[1] = packUint16(e.Version)
+	b[2], b[3] = packUint16(e.Opcode)
+	b[4], b[5] = packUint16(e.Error)
+	b[6] = byte(e.Id >> 56)
+	b[7] = byte(e.Id >> 48)
+	b[8] = byte(e.Id >> 40)
+	b[9] = byte(e.Id >> 32)
+	b[10] = byte(e.Id >> 24)
+	b[11] = byte(e.Id >> 16)
+	b[12] = byte(e.Id >> 8)
+	b[13] = byte(e.Id)
+	b[14] = byte(e.LeaseLife >> 24)
+	b[15] = byte(e.LeaseLife >> 16)
+	b[16] = byte(e.LeaseLife >> 8)
+	b[17] = byte(e.LeaseLife)
+	return b, nil
+}
+
+func (e *EDNS0_LLQ) unpack(b []byte) error {
+	if len(b) < 18 {
+		return ErrBuf
+	}
+	e.Version, _ = unpackUint16(b, 0)
+	e.Opcode, _ = unpackUint16(b, 2)
+	e.Error, _ = unpackUint16(b, 4)
+	e.Id = uint64(b[6])<<56 | uint64(b[6+1])<<48 | uint64(b[6+2])<<40 |
+		uint64(b[6+3])<<32 | uint64(b[6+4])<<24 | uint64(b[6+5])<<16 | uint64(b[6+6])<<8 | uint64(b[6+7])
+	e.LeaseLife = uint32(b[14])<<24 | uint32(b[14+1])<<16 | uint32(b[14+2])<<8 | uint32(b[14+3])
+	return nil
+}
+
+func (e *EDNS0_LLQ) String() string {
+	s := strconv.FormatUint(uint64(e.Version), 10) + " " + strconv.FormatUint(uint64(e.Opcode), 10) +
+		" " + strconv.FormatUint(uint64(e.Error), 10) + " " + strconv.FormatUint(uint64(e.Id), 10) +
+		" " + strconv.FormatUint(uint64(e.LeaseLife), 10)
+	return s
+}
+
+type EDNS0_DAU struct {
+	Code    uint16 // Always EDNS0DAU
+	AlgCode []uint8
+}
+
+func (e *EDNS0_DAU) Option() uint16        { return EDNS0DAU }
+func (e *EDNS0_DAU) pack() ([]byte, error) { return e.AlgCode, nil }
+func (e *EDNS0_DAU) unpack(b []byte) error { e.AlgCode = b; return nil }
+
+func (e *EDNS0_DAU) String() string {
+	s := ""
+	for i := 0; i < len(e.AlgCode); i++ {
+		if a, ok := AlgorithmToString[e.AlgCode[i]]; ok {
+			s += " " + a
+		} else {
+			s += " " + strconv.Itoa(int(e.AlgCode[i]))
+		}
+	}
+	return s
+}
+
+type EDNS0_DHU struct {
+	Code    uint16 // Always EDNS0DHU
+	AlgCode []uint8
+}
+
+func (e *EDNS0_DHU) Option() uint16        { return EDNS0DHU }
+func (e *EDNS0_DHU) pack() ([]byte, error) { return e.AlgCode, nil }
+func (e *EDNS0_DHU) unpack(b []byte) error { e.AlgCode = b; return nil }
+
+func (e *EDNS0_DHU) String() string {
+	s := ""
+	for i := 0; i < len(e.AlgCode); i++ {
+		if a, ok := HashToString[e.AlgCode[i]]; ok {
+			s += " " + a
+		} else {
+			s += " " + strconv.Itoa(int(e.AlgCode[i]))
+		}
+	}
+	return s
+}
+
+type EDNS0_N3U struct {
+	Code    uint16 // Always EDNS0N3U
+	AlgCode []uint8
+}
+
+func (e *EDNS0_N3U) Option() uint16        { return EDNS0N3U }
+func (e *EDNS0_N3U) pack() ([]byte, error) { return e.AlgCode, nil }
+func (e *EDNS0_N3U) unpack(b []byte) error { e.AlgCode = b; return nil }
+
+func (e *EDNS0_N3U) String() string {
+	// Re-use the hash map
+	s := ""
+	for i := 0; i < len(e.AlgCode); i++ {
+		if a, ok := HashToString[e.AlgCode[i]]; ok {
+			s += " " + a
+		} else {
+			s += " " + strconv.Itoa(int(e.AlgCode[i]))
+		}
+	}
+	return s
+}
+
+type EDNS0_EXPIRE struct {
+	Code   uint16 // Always EDNS0EXPIRE
+	Expire uint32
+}
+
+func (e *EDNS0_EXPIRE) Option() uint16 { return EDNS0EXPIRE }
+func (e *EDNS0_EXPIRE) String() string { return strconv.FormatUint(uint64(e.Expire), 10) }
+
+func (e *EDNS0_EXPIRE) pack() ([]byte, error) {
+	b := make([]byte, 4)
+	b[0] = byte(e.Expire >> 24)
+	b[1] = byte(e.Expire >> 16)
+	b[2] = byte(e.Expire >> 8)
+	b[3] = byte(e.Expire)
+	return b, nil
+}
+
+func (e *EDNS0_EXPIRE) unpack(b []byte) error {
+	if len(b) < 4 {
+		return ErrBuf
+	}
+	e.Expire = uint32(b[0])<<24 | uint32(b[1])<<16 | uint32(b[2])<<8 | uint32(b[3])
+	return nil
+}
+
+// The EDNS0_LOCAL option is used for local/experimental purposes. The option
+// code is recommended to be within the range [EDNS0LOCALSTART, EDNS0LOCALEND]
+// (RFC6891), although any unassigned code can actually be used.  The content of
+// the option is made available in Data, unaltered.
+// Basic use pattern for creating a local option:
+//
+//	o := new(dns.OPT)
+//	o.Hdr.Name = "."
+//	o.Hdr.Rrtype = dns.TypeOPT
+//	e := new(dns.EDNS0_LOCAL)
+//	e.Code = dns.EDNS0LOCALSTART
+//	e.Data = []byte{72, 82, 74}
+//	o.Option = append(o.Option, e)
+type EDNS0_LOCAL struct {
+	Code uint16
+	Data []byte
+}
+
+func (e *EDNS0_LOCAL) Option() uint16 { return e.Code }
+func (e *EDNS0_LOCAL) String() string {
+	return strconv.FormatInt(int64(e.Code), 10) + ":0x" + hex.EncodeToString(e.Data)
+}
+
+func (e *EDNS0_LOCAL) pack() ([]byte, error) {
+	b := make([]byte, len(e.Data))
+	copied := copy(b, e.Data)
+	if copied != len(e.Data) {
+		return nil, ErrBuf
+	}
+	return b, nil
+}
+
+func (e *EDNS0_LOCAL) unpack(b []byte) error {
+	e.Data = make([]byte, len(b))
+	copied := copy(e.Data, b)
+	if copied != len(b) {
+		return ErrBuf
+	}
+	return nil
+}

edns_test.go

@@ -0,0 +1,48 @@
+package dns
+
+import "testing"
+
+func TestOPTTtl(t *testing.T) {
+	e := &OPT{}
+	e.Hdr.Name = "."
+	e.Hdr.Rrtype = TypeOPT
+
+	if e.Do() {
+		t.Fail()
+	}
+
+	e.SetDo()
+	if !e.Do() {
+		t.Fail()
+	}
+
+	oldTtl := e.Hdr.Ttl
+
+	if e.Version() != 0 {
+		t.Fail()
+	}
+
+	e.SetVersion(42)
+	if e.Version() != 42 {
+		t.Fail()
+	}
+
+	e.SetVersion(0)
+	if e.Hdr.Ttl != oldTtl {
+		t.Fail()
+	}
+
+	if e.ExtendedRcode() != 0 {
+		t.Fail()
+	}
+
+	e.SetExtendedRcode(42)
+	if e.ExtendedRcode() != 42 {
+		t.Fail()
+	}
+
+	e.SetExtendedRcode(0)
+	if e.Hdr.Ttl != oldTtl {
+		t.Fail()
+	}
+}

example_test.go

@@ -0,0 +1,146 @@
+package dns_test
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net"
+
+	"github.com/miekg/dns"
+)
+
+// Retrieve the MX records for miek.nl.
+func ExampleMX() {
+	config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
+	c := new(dns.Client)
+	m := new(dns.Msg)
+	m.SetQuestion("miek.nl.", dns.TypeMX)
+	m.RecursionDesired = true
+	r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
+	if err != nil {
+		return
+	}
+	if r.Rcode != dns.RcodeSuccess {
+		return
+	}
+	for _, a := range r.Answer {
+		if mx, ok := a.(*dns.MX); ok {
+			fmt.Printf("%s\n", mx.String())
+		}
+	}
+}
+
+// Retrieve the DNSKEY records of a zone and convert them
+// to DS records for SHA1, SHA256 and SHA384.
+func ExampleDS() {
+	config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
+	c := new(dns.Client)
+	m := new(dns.Msg)
+	zone := "miek.nl"
+	m.SetQuestion(dns.Fqdn(zone), dns.TypeDNSKEY)
+	m.SetEdns0(4096, true)
+	r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
+	if err != nil {
+		return
+	}
+	if r.Rcode != dns.RcodeSuccess {
+		return
+	}
+	for _, k := range r.Answer {
+		if key, ok := k.(*dns.DNSKEY); ok {
+			for _, alg := range []uint8{dns.SHA1, dns.SHA256, dns.SHA384} {
+				fmt.Printf("%s; %d\n", key.ToDS(alg).String(), key.Flags)
+			}
+		}
+	}
+}
+
+const TypeAPAIR = 0x0F99
+
+type APAIR struct {
+	addr [2]net.IP
+}
+
+func NewAPAIR() dns.PrivateRdata { return new(APAIR) }
+
+func (rd *APAIR) String() string { return rd.addr[0].String() + " " + rd.addr[1].String() }
+func (rd *APAIR) Parse(txt []string) error {
+	if len(txt) != 2 {
+		return errors.New("two addresses required for APAIR")
+	}
+	for i, s := range txt {
+		ip := net.ParseIP(s)
+		if ip == nil {
+			return errors.New("invalid IP in APAIR text representation")
+		}
+		rd.addr[i] = ip
+	}
+	return nil
+}
+
+func (rd *APAIR) Pack(buf []byte) (int, error) {
+	b := append([]byte(rd.addr[0]), []byte(rd.addr[1])...)
+	n := copy(buf, b)
+	if n != len(b) {
+		return n, dns.ErrBuf
+	}
+	return n, nil
+}
+
+func (rd *APAIR) Unpack(buf []byte) (int, error) {
+	ln := net.IPv4len * 2
+	if len(buf) != ln {
+		return 0, errors.New("invalid length of APAIR rdata")
+	}
+	cp := make([]byte, ln)
+	copy(cp, buf) // clone bytes to use them in IPs
+
+	rd.addr[0] = net.IP(cp[:3])
+	rd.addr[1] = net.IP(cp[4:])
+
+	return len(buf), nil
+}
+
+func (rd *APAIR) Copy(dest dns.PrivateRdata) error {
+	cp := make([]byte, rd.Len())
+	_, err := rd.Pack(cp)
+	if err != nil {
+		return err
+	}
+
+	d := dest.(*APAIR)
+	d.addr[0] = net.IP(cp[:3])
+	d.addr[1] = net.IP(cp[4:])
+	return nil
+}
+
+func (rd *APAIR) Len() int {
+	return net.IPv4len * 2
+}
+
+func ExamplePrivateHandle() {
+	dns.PrivateHandle("APAIR", TypeAPAIR, NewAPAIR)
+	defer dns.PrivateHandleRemove(TypeAPAIR)
+
+	rr, err := dns.NewRR("miek.nl. APAIR (1.2.3.4    1.2.3.5)")
+	if err != nil {
+		log.Fatal("could not parse APAIR record: ", err)
+	}
+	fmt.Println(rr)
+	// Output: miek.nl.	3600	IN	APAIR	1.2.3.4 1.2.3.5
+
+	m := new(dns.Msg)
+	m.Id = 12345
+	m.SetQuestion("miek.nl.", TypeAPAIR)
+	m.Answer = append(m.Answer, rr)
+
+	fmt.Println(m)
+	// ;; opcode: QUERY, status: NOERROR, id: 12345
+	// ;; flags: rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
+	//
+	// ;; QUESTION SECTION:
+	// ;miek.nl.	IN	 APAIR
+	//
+	// ;; ANSWER SECTION:
+	// miek.nl.	3600	IN	APAIR	1.2.3.4 1.2.3.5
+}

format.go

@@ -0,0 +1,96 @@
+package dns
+
+import (
+	"net"
+	"reflect"
+	"strconv"
+)
+
+// NumField returns the number of rdata fields r has.
+func NumField(r RR) int {
+	return reflect.ValueOf(r).Elem().NumField() - 1 // Remove RR_Header
+}
+
+// Field returns the rdata field i as a string. Fields are indexed starting from 1.
+// RR types that holds slice data, for instance the NSEC type bitmap will return a single
+// string where the types are concatenated using a space.
+// Accessing non existing fields will cause a panic.
+func Field(r RR, i int) string {
+	if i == 0 {
+		return ""
+	}
+	d := reflect.ValueOf(r).Elem().Field(i)
+	switch k := d.Kind(); k {
+	case reflect.String:
+		return d.String()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return strconv.FormatInt(d.Int(), 10)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return strconv.FormatUint(d.Uint(), 10)
+	case reflect.Slice:
+		switch reflect.ValueOf(r).Elem().Type().Field(i).Tag {
+		case `dns:"a"`:
+			// TODO(miek): Hmm store this as 16 bytes
+			if d.Len() < net.IPv6len {
+				return net.IPv4(byte(d.Index(0).Uint()),
+					byte(d.Index(1).Uint()),
+					byte(d.Index(2).Uint()),
+					byte(d.Index(3).Uint())).String()
+			}
+			return net.IPv4(byte(d.Index(12).Uint()),
+				byte(d.Index(13).Uint()),
+				byte(d.Index(14).Uint()),
+				byte(d.Index(15).Uint())).String()
+		case `dns:"aaaa"`:
+			return net.IP{
+				byte(d.Index(0).Uint()),
+				byte(d.Index(1).Uint()),
+				byte(d.Index(2).Uint()),
+				byte(d.Index(3).Uint()),
+				byte(d.Index(4).Uint()),
+				byte(d.Index(5).Uint()),
+				byte(d.Index(6).Uint()),
+				byte(d.Index(7).Uint()),
+				byte(d.Index(8).Uint()),
+				byte(d.Index(9).Uint()),
+				byte(d.Index(10).Uint()),
+				byte(d.Index(11).Uint()),
+				byte(d.Index(12).Uint()),
+				byte(d.Index(13).Uint()),
+				byte(d.Index(14).Uint()),
+				byte(d.Index(15).Uint()),
+			}.String()
+		case `dns:"nsec"`:
+			if d.Len() == 0 {
+				return ""
+			}
+			s := Type(d.Index(0).Uint()).String()
+			for i := 1; i < d.Len(); i++ {
+				s += " " + Type(d.Index(i).Uint()).String()
+			}
+			return s
+		case `dns:"wks"`:
+			if d.Len() == 0 {
+				return ""
+			}
+			s := strconv.Itoa(int(d.Index(0).Uint()))
+			for i := 0; i < d.Len(); i++ {
+				s += " " + strconv.Itoa(int(d.Index(i).Uint()))
+			}
+			return s
+		default:
+			// if it does not have a tag its a string slice
+			fallthrough
+		case `dns:"txt"`:
+			if d.Len() == 0 {
+				return ""
+			}
+			s := d.Index(0).String()
+			for i := 1; i < d.Len(); i++ {
+				s += " " + d.Index(i).String()
+			}
+			return s
+		}
+	}
+	return ""
+}

fuzz_test.go

@@ -0,0 +1,25 @@
+package dns
+
+import "testing"
+
+func TestFuzzString(t *testing.T) {
+	testcases := []string{"", " MINFO ", "	RP ", "	NSEC 0 0", "	\" NSEC 0 0\"", "  \" MINFO \"",
+		";a ", ";a����������",
+		"	NSAP O ", "  NSAP N ",
+		" TYPE4 TYPE6a789a3bc0045c8a5fb42c7d1bd998f5444 IN 9579b47d46817afbd17273e6",
+		" TYPE45 3 3 4147994 TYPE\\(\\)\\)\\(\\)\\(\\(\\)\\(\\)\\)\\)\\(\\)\\(\\)\\(\\(\\R 948\"\")\\(\\)\\)\\)\\(\\ ",
+		"$GENERATE 0-3 ${441189,5039418474430,o}",
+		"$INCLUDE 00 TYPE00000000000n ",
+		"$INCLUDE PE4 TYPE061463623/727071511 \\(\\)\\$GENERATE 6-462/0",
+	}
+	for i, tc := range testcases {
+		rr, err := NewRR(tc)
+		if err == nil {
+			// rr can be nil because we can (for instance) just parse a comment
+			if rr == nil {
+				continue
+			}
+			t.Fatalf("parsed mailformed RR %d: %s", i, rr.String())
+		}
+	}
+}

idn/example_test.go

@@ -0,0 +1,18 @@
+package idn_test
+
+import (
+	"fmt"
+	"github.com/miekg/dns/idn"
+)
+
+func ExampleToPunycode() {
+	name := "インターネット.テスト"
+	fmt.Printf("%s -> %s", name, idn.ToPunycode(name))
+	// Output: インターネット.テスト -> xn--eckucmux0ukc.xn--zckzah
+}
+
+func ExampleFromPunycode() {
+	name := "xn--mgbaja8a1hpac.xn--mgbachtv"
+	fmt.Printf("%s -> %s", name, idn.FromPunycode(name))
+	// Output: xn--mgbaja8a1hpac.xn--mgbachtv -> الانترنت.اختبار
+}

idn/punycode.go

@@ -0,0 +1,373 @@
+// Package idn implements encoding from and to punycode as speficied by RFC 3492.
+package idn
+
+import (
+	"bytes"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/miekg/dns"
+)
+
+// Implementation idea from RFC itself and from from IDNA::Punycode created by
+// Tatsuhiko Miyagawa <miyagawa@bulknews.net> and released under Perl Artistic
+// License in 2002.
+
+const (
+	_MIN  rune = 1
+	_MAX  rune = 26
+	_SKEW rune = 38
+	_BASE rune = 36
+	_BIAS rune = 72
+	_N    rune = 128
+	_DAMP rune = 700
+
+	_DELIMITER = '-'
+	_PREFIX    = "xn--"
+)
+
+// ToPunycode converts unicode domain names to DNS-appropriate punycode names.
+// This function will return an empty string result for domain names with
+// invalid unicode strings. This function expects domain names in lowercase.
+func ToPunycode(s string) string {
+	// Early check to see if encoding is needed.
+	// This will prevent making heap allocations when not needed.
+	if !needToPunycode(s) {
+		return s
+	}
+
+	tokens := dns.SplitDomainName(s)
+	switch {
+	case s == "":
+		return ""
+	case tokens == nil: // s == .
+		return "."
+	case s[len(s)-1] == '.':
+		tokens = append(tokens, "")
+	}
+
+	for i := range tokens {
+		t := encode([]byte(tokens[i]))
+		if t == nil {
+			return ""
+		}
+		tokens[i] = string(t)
+	}
+	return strings.Join(tokens, ".")
+}
+
+// FromPunycode returns unicode domain name from provided punycode string.
+// This function expects punycode strings in lowercase.
+func FromPunycode(s string) string {
+	// Early check to see if decoding is needed.
+	// This will prevent making heap allocations when not needed.
+	if !needFromPunycode(s) {
+		return s
+	}
+
+	tokens := dns.SplitDomainName(s)
+	switch {
+	case s == "":
+		return ""
+	case tokens == nil: // s == .
+		return "."
+	case s[len(s)-1] == '.':
+		tokens = append(tokens, "")
+	}
+	for i := range tokens {
+		tokens[i] = string(decode([]byte(tokens[i])))
+	}
+	return strings.Join(tokens, ".")
+}
+
+// digitval converts single byte into meaningful value that's used to calculate decoded unicode character.
+const errdigit = 0xffff
+
+func digitval(code rune) rune {
+	switch {
+	case code >= 'A' && code <= 'Z':
+		return code - 'A'
+	case code >= 'a' && code <= 'z':
+		return code - 'a'
+	case code >= '0' && code <= '9':
+		return code - '0' + 26
+	}
+	return errdigit
+}
+
+// lettercode finds BASE36 byte (a-z0-9) based on calculated number.
+func lettercode(digit rune) rune {
+	switch {
+	case digit >= 0 && digit <= 25:
+		return digit + 'a'
+	case digit >= 26 && digit <= 36:
+		return digit - 26 + '0'
+	}
+	panic("dns: not reached")
+}
+
+// adapt calculates next bias to be used for next iteration delta.
+func adapt(delta rune, numpoints int, firsttime bool) rune {
+	if firsttime {
+		delta /= _DAMP
+	} else {
+		delta /= 2
+	}
+
+	var k rune
+	for delta = delta + delta/rune(numpoints); delta > (_BASE-_MIN)*_MAX/2; k += _BASE {
+		delta /= _BASE - _MIN
+	}
+
+	return k + ((_BASE-_MIN+1)*delta)/(delta+_SKEW)
+}
+
+// next finds minimal rune (one with lowest codepoint value) that should be equal or above boundary.
+func next(b []rune, boundary rune) rune {
+	if len(b) == 0 {
+		panic("dns: invalid set of runes to determine next one")
+	}
+	m := b[0]
+	for _, x := range b[1:] {
+		if x >= boundary && (m < boundary || x < m) {
+			m = x
+		}
+	}
+	return m
+}
+
+// preprune converts unicode rune to lower case. At this time it's not
+// supporting all things described in RFCs.
+func preprune(r rune) rune {
+	if unicode.IsUpper(r) {
+		r = unicode.ToLower(r)
+	}
+	return r
+}
+
+// tfunc is a function that helps calculate each character weight.
+func tfunc(k, bias rune) rune {
+	switch {
+	case k <= bias:
+		return _MIN
+	case k >= bias+_MAX:
+		return _MAX
+	}
+	return k - bias
+}
+
+// needToPunycode returns true for strings that require punycode encoding
+// (contain unicode characters).
+func needToPunycode(s string) bool {
+	// This function is very similar to bytes.Runes. We don't use bytes.Runes
+	// because it makes a heap allocation that's not needed here.
+	for i := 0; len(s) > 0; i++ {
+		r, l := utf8.DecodeRuneInString(s)
+		if r > 0x7f {
+			return true
+		}
+		s = s[l:]
+	}
+	return false
+}
+
+// needFromPunycode returns true for strings that require punycode decoding.
+func needFromPunycode(s string) bool {
+	if s == "." {
+		return false
+	}
+
+	off := 0
+	end := false
+	pl := len(_PREFIX)
+	sl := len(s)
+
+	// If s starts with _PREFIX.
+	if sl > pl && s[off:off+pl] == _PREFIX {
+		return true
+	}
+
+	for {
+		// Find the part after the next ".".
+		off, end = dns.NextLabel(s, off)
+		if end {
+			return false
+		}
+		// If this parts starts with _PREFIX.
+		if sl-off > pl && s[off:off+pl] == _PREFIX {
+			return true
+		}
+	}
+}
+
+// encode transforms Unicode input bytes (that represent DNS label) into
+// punycode bytestream. This function would return nil if there's an invalid
+// character in the label.
+func encode(input []byte) []byte {
+	n, bias := _N, _BIAS
+
+	b := bytes.Runes(input)
+	for i := range b {
+		if !isValidRune(b[i]) {
+			return nil
+		}
+
+		b[i] = preprune(b[i])
+	}
+
+	basic := make([]byte, 0, len(b))
+	for _, ltr := range b {
+		if ltr <= 0x7f {
+			basic = append(basic, byte(ltr))
+		}
+	}
+	basiclen := len(basic)
+	fulllen := len(b)
+	if basiclen == fulllen {
+		return basic
+	}
+
+	var out bytes.Buffer
+
+	out.WriteString(_PREFIX)
+	if basiclen > 0 {
+		out.Write(basic)
+		out.WriteByte(_DELIMITER)
+	}
+
+	var (
+		ltr, nextltr rune
+		delta, q     rune // delta calculation (see rfc)
+		t, k, cp     rune // weight and codepoint calculation
+	)
+
+	s := &bytes.Buffer{}
+	for h := basiclen; h < fulllen; n, delta = n+1, delta+1 {
+		nextltr = next(b, n)
+		s.Truncate(0)
+		s.WriteRune(nextltr)
+		delta, n = delta+(nextltr-n)*rune(h+1), nextltr
+
+		for _, ltr = range b {
+			if ltr < n {
+				delta++
+			}
+			if ltr == n {
+				q = delta
+				for k = _BASE; ; k += _BASE {
+					t = tfunc(k, bias)
+					if q < t {
+						break
+					}
+					cp = t + ((q - t) % (_BASE - t))
+					out.WriteRune(lettercode(cp))
+					q = (q - t) / (_BASE - t)
+				}
+
+				out.WriteRune(lettercode(q))
+
+				bias = adapt(delta, h+1, h == basiclen)
+				h, delta = h+1, 0
+			}
+		}
+	}
+	return out.Bytes()
+}
+
+// decode transforms punycode input bytes (that represent DNS label) into Unicode bytestream.
+func decode(b []byte) []byte {
+	src := b // b would move and we need to keep it
+
+	n, bias := _N, _BIAS
+	if !bytes.HasPrefix(b, []byte(_PREFIX)) {
+		return b
+	}
+	out := make([]rune, 0, len(b))
+	b = b[len(_PREFIX):]
+	for pos := len(b) - 1; pos >= 0; pos-- {
+		// only last delimiter is our interest
+		if b[pos] == _DELIMITER {
+			out = append(out, bytes.Runes(b[:pos])...)
+			b = b[pos+1:] // trim source string
+			break
+		}
+	}
+	if len(b) == 0 {
+		return src
+	}
+	var (
+		i, oldi, w rune
+		ch         byte
+		t, digit   rune
+		ln         int
+	)
+
+	for i = 0; len(b) > 0; i++ {
+		oldi, w = i, 1
+		for k := _BASE; len(b) > 0; k += _BASE {
+			ch, b = b[0], b[1:]
+			digit = digitval(rune(ch))
+			if digit == errdigit {
+				return src
+			}
+			i += digit * w
+			if i < 0 {
+				// safety check for rune overflow
+				return src
+			}
+
+			t = tfunc(k, bias)
+			if digit < t {
+				break
+			}
+
+			w *= _BASE - t
+		}
+		ln = len(out) + 1
+		bias = adapt(i-oldi, ln, oldi == 0)
+		n += i / rune(ln)
+		i = i % rune(ln)
+		// insert
+		out = append(out, 0)
+		copy(out[i+1:], out[i:])
+		out[i] = n
+	}
+
+	var ret bytes.Buffer
+	for _, r := range out {
+		ret.WriteRune(r)
+	}
+	return ret.Bytes()
+}
+
+// isValidRune checks if the character is valid. We will look for the
+// character property in the code points list. For now we aren't checking special
+// rules in case of contextual property
+func isValidRune(r rune) bool {
+	return findProperty(r) == propertyPVALID
+}
+
+// findProperty will try to check the code point property of the given
+// character. It will use a binary search algorithm as we have a slice of
+// ordered ranges (average case performance O(log n))
+func findProperty(r rune) property {
+	imin, imax := 0, len(codePoints)
+
+	for imax >= imin {
+		imid := (imin + imax) / 2
+
+		codePoint := codePoints[imid]
+		if (codePoint.start == r && codePoint.end == 0) || (codePoint.start <= r && codePoint.end >= r) {
+			return codePoint.state
+		}
+
+		if (codePoint.end > 0 && codePoint.end < r) || (codePoint.end == 0 && codePoint.start < r) {
+			imin = imid + 1
+		} else {
+			imax = imid - 1
+		}
+	}
+
+	return propertyUnknown
+}

idn/punycode_test.go

@@ -0,0 +1,116 @@
+package idn
+
+import (
+	"strings"
+	"testing"
+)
+
+var testcases = [][2]string{
+	{"", ""},
+	{"a", "a"},
+	{"a-b", "a-b"},
+	{"a-b-c", "a-b-c"},
+	{"abc", "abc"},
+	{"я", "xn--41a"},
+	{"zя", "xn--z-0ub"},
+	{"яZ", "xn--z-zub"},
+	{"а-я", "xn----7sb8g"},
+	{"إختبار", "xn--kgbechtv"},
+	{"آزمایشی", "xn--hgbk6aj7f53bba"},
+	{"测试", "xn--0zwm56d"},
+	{"測試", "xn--g6w251d"},
+	{"испытание", "xn--80akhbyknj4f"},
+	{"परीक्षा", "xn--11b5bs3a9aj6g"},
+	{"δοκιμή", "xn--jxalpdlp"},
+	{"테스트", "xn--9t4b11yi5a"},
+	{"טעסט", "xn--deba0ad"},
+	{"テスト", "xn--zckzah"},
+	{"பரிட்சை", "xn--hlcj6aya9esc7a"},
+	{"mamão-com-açúcar", "xn--mamo-com-acar-yeb1e6q"},
+	{"σ", "xn--4xa"},
+}
+
+func TestEncodeDecodePunycode(t *testing.T) {
+	for _, tst := range testcases {
+		enc := encode([]byte(tst[0]))
+		if string(enc) != tst[1] {
+			t.Errorf("%s encodeded as %s but should be %s", tst[0], enc, tst[1])
+		}
+		dec := decode([]byte(tst[1]))
+		if string(dec) != strings.ToLower(tst[0]) {
+			t.Errorf("%s decoded as %s but should be %s", tst[1], dec, strings.ToLower(tst[0]))
+		}
+	}
+}
+
+func TestToFromPunycode(t *testing.T) {
+	for _, tst := range testcases {
+		// assert unicode.com == punycode.com
+		full := ToPunycode(tst[0] + ".com")
+		if full != tst[1]+".com" {
+			t.Errorf("invalid result from string conversion to punycode, %s and should be %s.com", full, tst[1])
+		}
+		// assert punycode.punycode == unicode.unicode
+		decoded := FromPunycode(tst[1] + "." + tst[1])
+		if decoded != strings.ToLower(tst[0]+"."+tst[0]) {
+			t.Errorf("invalid result from string conversion to punycode, %s and should be %s.%s", decoded, tst[0], tst[0])
+		}
+	}
+}
+
+func TestEncodeDecodeFinalPeriod(t *testing.T) {
+	for _, tst := range testcases {
+		// assert unicode.com. == punycode.com.
+		full := ToPunycode(tst[0] + ".")
+		if full != tst[1]+"." {
+			t.Errorf("invalid result from string conversion to punycode when period added at the end, %#v and should be %#v", full, tst[1]+".")
+		}
+		// assert punycode.com. == unicode.com.
+		decoded := FromPunycode(tst[1] + ".")
+		if decoded != strings.ToLower(tst[0]+".") {
+			t.Errorf("invalid result from string conversion to punycode when period added, %#v and should be %#v", decoded, tst[0]+".")
+		}
+		full = ToPunycode(tst[0])
+		if full != tst[1] {
+			t.Errorf("invalid result from string conversion to punycode when no period added at the end, %#v and should be %#v", full, tst[1]+".")
+		}
+		// assert punycode.com. == unicode.com.
+		decoded = FromPunycode(tst[1])
+		if decoded != strings.ToLower(tst[0]) {
+			t.Errorf("invalid result from string conversion to punycode when no period added, %#v and should be %#v", decoded, tst[0]+".")
+		}
+	}
+}
+
+var invalidACEs = []string{
+	"xn--*",
+	"xn--",
+	"xn---",
+	"xn--a000000000",
+}
+
+func TestInvalidPunycode(t *testing.T) {
+	for _, d := range invalidACEs {
+		s := FromPunycode(d)
+		if s != d {
+			t.Errorf("Changed invalid name %s to %#v", d, s)
+		}
+	}
+}
+
+// You can verify the labels that are valid or not comparing to the Verisign
+// website: http://mct.verisign-grs.com/
+var invalidUnicodes = []string{
+	"Σ",
+	"ЯZ",
+	"Испытание",
+}
+
+func TestInvalidUnicodes(t *testing.T) {
+	for _, d := range invalidUnicodes {
+		s := ToPunycode(d)
+		if s != "" {
+			t.Errorf("Changed invalid name %s to %#v", d, s)
+		}
+	}
+}

labels.go

@@ -0,0 +1,162 @@
+package dns
+
+// Holds a bunch of helper functions for dealing with labels.
+
+// SplitDomainName splits a name string into it's labels.
+// www.miek.nl. returns []string{"www", "miek", "nl"}
+// The root label (.) returns nil. Note that using
+// strings.Split(s) will work in most cases, but does not handle
+// escaped dots (\.) for instance.
+func SplitDomainName(s string) (labels []string) {
+	if len(s) == 0 {
+		return nil
+	}
+	fqdnEnd := 0 // offset of the final '.' or the length of the name
+	idx := Split(s)
+	begin := 0
+	if s[len(s)-1] == '.' {
+		fqdnEnd = len(s) - 1
+	} else {
+		fqdnEnd = len(s)
+	}
+
+	switch len(idx) {
+	case 0:
+		return nil
+	case 1:
+		// no-op
+	default:
+		end := 0
+		for i := 1; i < len(idx); i++ {
+			end = idx[i]
+			labels = append(labels, s[begin:end-1])
+			begin = end
+		}
+	}
+
+	labels = append(labels, s[begin:fqdnEnd])
+	return labels
+}
+
+// CompareDomainName compares the names s1 and s2 and
+// returns how many labels they have in common starting from the *right*.
+// The comparison stops at the first inequality. The names are not downcased
+// before the comparison.
+//
+// www.miek.nl. and miek.nl. have two labels in common: miek and nl
+// www.miek.nl. and www.bla.nl. have one label in common: nl
+func CompareDomainName(s1, s2 string) (n int) {
+	s1 = Fqdn(s1)
+	s2 = Fqdn(s2)
+	l1 := Split(s1)
+	l2 := Split(s2)
+
+	// the first check: root label
+	if l1 == nil || l2 == nil {
+		return
+	}
+
+	j1 := len(l1) - 1 // end
+	i1 := len(l1) - 2 // start
+	j2 := len(l2) - 1
+	i2 := len(l2) - 2
+	// the second check can be done here: last/only label
+	// before we fall through into the for-loop below
+	if s1[l1[j1]:] == s2[l2[j2]:] {
+		n++
+	} else {
+		return
+	}
+	for {
+		if i1 < 0 || i2 < 0 {
+			break
+		}
+		if s1[l1[i1]:l1[j1]] == s2[l2[i2]:l2[j2]] {
+			n++
+		} else {
+			break
+		}
+		j1--
+		i1--
+		j2--
+		i2--
+	}
+	return
+}
+
+// CountLabel counts the the number of labels in the string s.
+func CountLabel(s string) (labels int) {
+	if s == "." {
+		return
+	}
+	off := 0
+	end := false
+	for {
+		off, end = NextLabel(s, off)
+		labels++
+		if end {
+			return
+		}
+	}
+}
+
+// Split splits a name s into its label indexes.
+// www.miek.nl. returns []int{0, 4, 9}, www.miek.nl also returns []int{0, 4, 9}.
+// The root name (.) returns nil. Also see SplitDomainName.
+func Split(s string) []int {
+	if s == "." {
+		return nil
+	}
+	idx := make([]int, 1, 3)
+	off := 0
+	end := false
+
+	for {
+		off, end = NextLabel(s, off)
+		if end {
+			return idx
+		}
+		idx = append(idx, off)
+	}
+}
+
+// NextLabel returns the index of the start of the next label in the
+// string s starting at offset.
+// The bool end is true when the end of the string has been reached.
+// Also see PrevLabel.
+func NextLabel(s string, offset int) (i int, end bool) {
+	quote := false
+	for i = offset; i < len(s)-1; i++ {
+		switch s[i] {
+		case '\\':
+			quote = !quote
+		default:
+			quote = false
+		case '.':
+			if quote {
+				quote = !quote
+				continue
+			}
+			return i + 1, false
+		}
+	}
+	return i + 1, true
+}
+
+// PrevLabel returns the index of the label when starting from the right and
+// jumping n labels to the left.
+// The bool start is true when the start of the string has been overshot.
+// Also see NextLabel.
+func PrevLabel(s string, n int) (i int, start bool) {
+	if n == 0 {
+		return len(s), false
+	}
+	lab := Split(s)
+	if lab == nil {
+		return 0, true
+	}
+	if n > len(lab) {
+		return 0, true
+	}
+	return lab[len(lab)-n], false
+}

labels_test.go

@@ -0,0 +1,199 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestCompareDomainName(t *testing.T) {
+	s1 := "www.miek.nl."
+	s2 := "miek.nl."
+	s3 := "www.bla.nl."
+	s4 := "nl.www.bla."
+	s5 := "nl"
+	s6 := "miek.nl"
+
+	if CompareDomainName(s1, s2) != 2 {
+		t.Errorf("%s with %s should be %d", s1, s2, 2)
+	}
+	if CompareDomainName(s1, s3) != 1 {
+		t.Errorf("%s with %s should be %d", s1, s3, 1)
+	}
+	if CompareDomainName(s3, s4) != 0 {
+		t.Errorf("%s with %s should be %d", s3, s4, 0)
+	}
+	// Non qualified tests
+	if CompareDomainName(s1, s5) != 1 {
+		t.Errorf("%s with %s should be %d", s1, s5, 1)
+	}
+	if CompareDomainName(s1, s6) != 2 {
+		t.Errorf("%s with %s should be %d", s1, s5, 2)
+	}
+
+	if CompareDomainName(s1, ".") != 0 {
+		t.Errorf("%s with %s should be %d", s1, s5, 0)
+	}
+	if CompareDomainName(".", ".") != 0 {
+		t.Errorf("%s with %s should be %d", ".", ".", 0)
+	}
+}
+
+func TestSplit(t *testing.T) {
+	splitter := map[string]int{
+		"www.miek.nl.":   3,
+		"www.miek.nl":    3,
+		"www..miek.nl":   4,
+		`www\.miek.nl.`:  2,
+		`www\\.miek.nl.`: 3,
+		".":              0,
+		"nl.":            1,
+		"nl":             1,
+		"com.":           1,
+		".com.":          2,
+	}
+	for s, i := range splitter {
+		if x := len(Split(s)); x != i {
+			t.Errorf("labels should be %d, got %d: %s %v", i, x, s, Split(s))
+		} else {
+			t.Logf("%s %v", s, Split(s))
+		}
+	}
+}
+
+func TestSplit2(t *testing.T) {
+	splitter := map[string][]int{
+		"www.miek.nl.": {0, 4, 9},
+		"www.miek.nl":  {0, 4, 9},
+		"nl":           {0},
+	}
+	for s, i := range splitter {
+		x := Split(s)
+		switch len(i) {
+		case 1:
+			if x[0] != i[0] {
+				t.Errorf("labels should be %v, got %v: %s", i, x, s)
+			}
+		default:
+			if x[0] != i[0] || x[1] != i[1] || x[2] != i[2] {
+				t.Errorf("labels should be %v, got %v: %s", i, x, s)
+			}
+		}
+	}
+}
+
+func TestPrevLabel(t *testing.T) {
+	type prev struct {
+		string
+		int
+	}
+	prever := map[prev]int{
+		prev{"www.miek.nl.", 0}: 12,
+		prev{"www.miek.nl.", 1}: 9,
+		prev{"www.miek.nl.", 2}: 4,
+
+		prev{"www.miek.nl", 0}: 11,
+		prev{"www.miek.nl", 1}: 9,
+		prev{"www.miek.nl", 2}: 4,
+
+		prev{"www.miek.nl.", 5}: 0,
+		prev{"www.miek.nl", 5}:  0,
+
+		prev{"www.miek.nl.", 3}: 0,
+		prev{"www.miek.nl", 3}:  0,
+	}
+	for s, i := range prever {
+		x, ok := PrevLabel(s.string, s.int)
+		if i != x {
+			t.Errorf("label should be %d, got %d, %t: preving %d, %s", i, x, ok, s.int, s.string)
+		}
+	}
+}
+
+func TestCountLabel(t *testing.T) {
+	splitter := map[string]int{
+		"www.miek.nl.": 3,
+		"www.miek.nl":  3,
+		"nl":           1,
+		".":            0,
+	}
+	for s, i := range splitter {
+		x := CountLabel(s)
+		if x != i {
+			t.Errorf("CountLabel should have %d, got %d", i, x)
+		}
+	}
+}
+
+func TestSplitDomainName(t *testing.T) {
+	labels := map[string][]string{
+		"miek.nl":       {"miek", "nl"},
+		".":             nil,
+		"www.miek.nl.":  {"www", "miek", "nl"},
+		"www.miek.nl":   {"www", "miek", "nl"},
+		"www..miek.nl":  {"www", "", "miek", "nl"},
+		`www\.miek.nl`:  {`www\.miek`, "nl"},
+		`www\\.miek.nl`: {`www\\`, "miek", "nl"},
+	}
+domainLoop:
+	for domain, splits := range labels {
+		parts := SplitDomainName(domain)
+		if len(parts) != len(splits) {
+			t.Errorf("SplitDomainName returned %v for %s, expected %v", parts, domain, splits)
+			continue domainLoop
+		}
+		for i := range parts {
+			if parts[i] != splits[i] {
+				t.Errorf("SplitDomainName returned %v for %s, expected %v", parts, domain, splits)
+				continue domainLoop
+			}
+		}
+	}
+}
+
+func TestIsDomainName(t *testing.T) {
+	type ret struct {
+		ok  bool
+		lab int
+	}
+	names := map[string]*ret{
+		"..":               {false, 1},
+		"@.":               {true, 1},
+		"www.example.com":  {true, 3},
+		"www.e%ample.com":  {true, 3},
+		"www.example.com.": {true, 3},
+		"mi\\k.nl.":        {true, 2},
+		"mi\\k.nl":         {true, 2},
+	}
+	for d, ok := range names {
+		l, k := IsDomainName(d)
+		if ok.ok != k || ok.lab != l {
+			t.Errorf(" got %v %d for %s ", k, l, d)
+			t.Errorf("have %v %d for %s ", ok.ok, ok.lab, d)
+		}
+	}
+}
+
+func BenchmarkSplitLabels(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Split("www.example.com")
+	}
+}
+
+func BenchmarkLenLabels(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		CountLabel("www.example.com")
+	}
+}
+
+func BenchmarkCompareLabels(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		CompareDomainName("www.example.com", "aa.example.com")
+	}
+}
+
+func BenchmarkIsSubDomain(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		IsSubDomain("www.example.com", "aa.example.com")
+		IsSubDomain("example.com", "aa.example.com")
+		IsSubDomain("miek.nl", "aa.example.com")
+	}
+}

nsecx.go

@@ -0,0 +1,112 @@
+package dns
+
+import (
+	"crypto/sha1"
+	"hash"
+	"io"
+	"strings"
+)
+
+type saltWireFmt struct {
+	Salt string `dns:"size-hex"`
+}
+
+// HashName hashes a string (label) according to RFC 5155. It returns the hashed string in
+// uppercase.
+func HashName(label string, ha uint8, iter uint16, salt string) string {
+	saltwire := new(saltWireFmt)
+	saltwire.Salt = salt
+	wire := make([]byte, DefaultMsgSize)
+	n, err := PackStruct(saltwire, wire, 0)
+	if err != nil {
+		return ""
+	}
+	wire = wire[:n]
+	name := make([]byte, 255)
+	off, err := PackDomainName(strings.ToLower(label), name, 0, nil, false)
+	if err != nil {
+		return ""
+	}
+	name = name[:off]
+	var s hash.Hash
+	switch ha {
+	case SHA1:
+		s = sha1.New()
+	default:
+		return ""
+	}
+
+	// k = 0
+	name = append(name, wire...)
+	io.WriteString(s, string(name))
+	nsec3 := s.Sum(nil)
+	// k > 0
+	for k := uint16(0); k < iter; k++ {
+		s.Reset()
+		nsec3 = append(nsec3, wire...)
+		io.WriteString(s, string(nsec3))
+		nsec3 = s.Sum(nil)
+	}
+	return toBase32(nsec3)
+}
+
+// Denialer is an interface that should be implemented by types that are used to denial
+// answers in DNSSEC.
+type Denialer interface {
+	// Cover will check if the (unhashed) name is being covered by this NSEC or NSEC3.
+	Cover(name string) bool
+	// Match will check if the ownername matches the (unhashed) name for this NSEC3 or NSEC3.
+	Match(name string) bool
+}
+
+// Cover implements the Denialer interface.
+func (rr *NSEC) Cover(name string) bool {
+	return true
+}
+
+// Match implements the Denialer interface.
+func (rr *NSEC) Match(name string) bool {
+	return true
+}
+
+// Cover implements the Denialer interface.
+func (rr *NSEC3) Cover(name string) bool {
+	// FIXME(miek): check if the zones match
+	// FIXME(miek): check if we're not dealing with parent nsec3
+	hname := HashName(name, rr.Hash, rr.Iterations, rr.Salt)
+	labels := Split(rr.Hdr.Name)
+	if len(labels) < 2 {
+		return false
+	}
+	hash := strings.ToUpper(rr.Hdr.Name[labels[0] : labels[1]-1]) // -1 to remove the dot
+	if hash == rr.NextDomain {
+		return false // empty interval
+	}
+	if hash > rr.NextDomain { // last name, points to apex
+		// hname > hash
+		// hname > rr.NextDomain
+		// TODO(miek)
+	}
+	if hname <= hash {
+		return false
+	}
+	if hname >= rr.NextDomain {
+		return false
+	}
+	return true
+}
+
+// Match implements the Denialer interface.
+func (rr *NSEC3) Match(name string) bool {
+	// FIXME(miek): Check if we are in the same zone
+	hname := HashName(name, rr.Hash, rr.Iterations, rr.Salt)
+	labels := Split(rr.Hdr.Name)
+	if len(labels) < 2 {
+		return false
+	}
+	hash := strings.ToUpper(rr.Hdr.Name[labels[0] : labels[1]-1]) // -1 to remove the .
+	if hash == hname {
+		return true
+	}
+	return false
+}

nsecx_test.go

@@ -0,0 +1,29 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestPackNsec3(t *testing.T) {
+	nsec3 := HashName("dnsex.nl.", SHA1, 0, "DEAD")
+	if nsec3 != "ROCCJAE8BJJU7HN6T7NG3TNM8ACRS87J" {
+		t.Error(nsec3)
+	}
+
+	nsec3 = HashName("a.b.c.example.org.", SHA1, 2, "DEAD")
+	if nsec3 != "6LQ07OAHBTOOEU2R9ANI2AT70K5O0RCG" {
+		t.Error(nsec3)
+	}
+}
+
+func TestNsec3(t *testing.T) {
+	// examples taken from .nl
+	nsec3, _ := NewRR("39p91242oslggest5e6a7cci4iaeqvnk.nl. IN NSEC3 1 1 5 F10E9F7EA83FC8F3 39P99DCGG0MDLARTCRMCF6OFLLUL7PR6 NS DS RRSIG")
+	if !nsec3.(*NSEC3).Cover("snasajsksasasa.nl.") { // 39p94jrinub66hnpem8qdpstrec86pg3
+		t.Error("39p94jrinub66hnpem8qdpstrec86pg3. should be covered by 39p91242oslggest5e6a7cci4iaeqvnk.nl. - 39P99DCGG0MDLARTCRMCF6OFLLUL7PR6")
+	}
+	nsec3, _ = NewRR("sk4e8fj94u78smusb40o1n0oltbblu2r.nl. IN NSEC3 1 1 5 F10E9F7EA83FC8F3 SK4F38CQ0ATIEI8MH3RGD0P5I4II6QAN NS SOA TXT RRSIG DNSKEY NSEC3PARAM")
+	if !nsec3.(*NSEC3).Match("nl.") { // sk4e8fj94u78smusb40o1n0oltbblu2r.nl.
+		t.Error("sk4e8fj94u78smusb40o1n0oltbblu2r.nl. should match sk4e8fj94u78smusb40o1n0oltbblu2r.nl.")
+	}
+}

privaterr.go

@@ -0,0 +1,117 @@
+package dns
+
+import (
+	"fmt"
+	"strings"
+)
+
+// PrivateRdata is an interface used for implementing "Private Use" RR types, see
+// RFC 6895. This allows one to experiment with new RR types, without requesting an
+// official type code. Also see dns.PrivateHandle and dns.PrivateHandleRemove.
+type PrivateRdata interface {
+	// String returns the text presentaton of the Rdata of the Private RR.
+	String() string
+	// Parse parses the Rdata of the private RR.
+	Parse([]string) error
+	// Pack is used when packing a private RR into a buffer.
+	Pack([]byte) (int, error)
+	// Unpack is used when unpacking a private RR from a buffer.
+	// TODO(miek): diff. signature than Pack, see edns0.go for instance.
+	Unpack([]byte) (int, error)
+	// Copy copies the Rdata.
+	Copy(PrivateRdata) error
+	// Len returns the length in octets of the Rdata.
+	Len() int
+}
+
+// PrivateRR represents an RR that uses a PrivateRdata user-defined type.
+// It mocks normal RRs and implements dns.RR interface.
+type PrivateRR struct {
+	Hdr  RR_Header
+	Data PrivateRdata
+}
+
+func mkPrivateRR(rrtype uint16) *PrivateRR {
+	// Panics if RR is not an instance of PrivateRR.
+	rrfunc, ok := TypeToRR[rrtype]
+	if !ok {
+		panic(fmt.Sprintf("dns: invalid operation with Private RR type %d", rrtype))
+	}
+
+	anyrr := rrfunc()
+	switch rr := anyrr.(type) {
+	case *PrivateRR:
+		return rr
+	}
+	panic(fmt.Sprintf("dns: RR is not a PrivateRR, TypeToRR[%d] generator returned %T", rrtype, anyrr))
+}
+
+// Header return the RR header of r.
+func (r *PrivateRR) Header() *RR_Header { return &r.Hdr }
+
+func (r *PrivateRR) String() string { return r.Hdr.String() + r.Data.String() }
+
+// Private len and copy parts to satisfy RR interface.
+func (r *PrivateRR) len() int { return r.Hdr.len() + r.Data.Len() }
+func (r *PrivateRR) copy() RR {
+	// make new RR like this:
+	rr := mkPrivateRR(r.Hdr.Rrtype)
+	newh := r.Hdr.copyHeader()
+	rr.Hdr = *newh
+
+	err := r.Data.Copy(rr.Data)
+	if err != nil {
+		panic("dns: got value that could not be used to copy Private rdata")
+	}
+	return rr
+}
+
+// PrivateHandle registers a private resource record type. It requires
+// string and numeric representation of private RR type and generator function as argument.
+func PrivateHandle(rtypestr string, rtype uint16, generator func() PrivateRdata) {
+	rtypestr = strings.ToUpper(rtypestr)
+
+	TypeToRR[rtype] = func() RR { return &PrivateRR{RR_Header{}, generator()} }
+	TypeToString[rtype] = rtypestr
+	StringToType[rtypestr] = rtype
+
+	setPrivateRR := func(h RR_Header, c chan lex, o, f string) (RR, *ParseError, string) {
+		rr := mkPrivateRR(h.Rrtype)
+		rr.Hdr = h
+
+		var l lex
+		text := make([]string, 0, 2) // could be 0..N elements, median is probably 1
+	FETCH:
+		for {
+			// TODO(miek): we could also be returning _QUOTE, this might or might not
+			// be an issue (basically parsing TXT becomes hard)
+			switch l = <-c; l.value {
+			case zNewline, zEOF:
+				break FETCH
+			case zString:
+				text = append(text, l.token)
+			}
+		}
+
+		err := rr.Data.Parse(text)
+		if err != nil {
+			return nil, &ParseError{f, err.Error(), l}, ""
+		}
+
+		return rr, nil, ""
+	}
+
+	typeToparserFunc[rtype] = parserFunc{setPrivateRR, true}
+}
+
+// PrivateHandleRemove removes defenitions required to support private RR type.
+func PrivateHandleRemove(rtype uint16) {
+	rtypestr, ok := TypeToString[rtype]
+	if ok {
+		delete(TypeToRR, rtype)
+		delete(TypeToString, rtype)
+		delete(typeToparserFunc, rtype)
+		delete(StringToType, rtypestr)
+	}
+	return
+}

privaterr_test.go

@@ -0,0 +1,170 @@
+package dns_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/miekg/dns"
+)
+
+const TypeISBN uint16 = 0x0F01
+
+// A crazy new RR type :)
+type ISBN struct {
+	x string // rdata with 10 or 13 numbers, dashes or spaces allowed
+}
+
+func NewISBN() dns.PrivateRdata { return &ISBN{""} }
+
+func (rd *ISBN) Len() int       { return len([]byte(rd.x)) }
+func (rd *ISBN) String() string { return rd.x }
+
+func (rd *ISBN) Parse(txt []string) error {
+	rd.x = strings.TrimSpace(strings.Join(txt, " "))
+	return nil
+}
+
+func (rd *ISBN) Pack(buf []byte) (int, error) {
+	b := []byte(rd.x)
+	n := copy(buf, b)
+	if n != len(b) {
+		return n, dns.ErrBuf
+	}
+	return n, nil
+}
+
+func (rd *ISBN) Unpack(buf []byte) (int, error) {
+	rd.x = string(buf)
+	return len(buf), nil
+}
+
+func (rd *ISBN) Copy(dest dns.PrivateRdata) error {
+	isbn, ok := dest.(*ISBN)
+	if !ok {
+		return dns.ErrRdata
+	}
+	isbn.x = rd.x
+	return nil
+}
+
+var testrecord = strings.Join([]string{"example.org.", "3600", "IN", "ISBN", "12-3 456789-0-123"}, "\t")
+
+func TestPrivateText(t *testing.T) {
+	dns.PrivateHandle("ISBN", TypeISBN, NewISBN)
+	defer dns.PrivateHandleRemove(TypeISBN)
+
+	rr, err := dns.NewRR(testrecord)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if rr.String() != testrecord {
+		t.Errorf("record string representation did not match original %#v != %#v", rr.String(), testrecord)
+	} else {
+		t.Log(rr.String())
+	}
+}
+
+func TestPrivateByteSlice(t *testing.T) {
+	dns.PrivateHandle("ISBN", TypeISBN, NewISBN)
+	defer dns.PrivateHandleRemove(TypeISBN)
+
+	rr, err := dns.NewRR(testrecord)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	buf := make([]byte, 100)
+	off, err := dns.PackRR(rr, buf, 0, nil, false)
+	if err != nil {
+		t.Errorf("got error packing ISBN: %v", err)
+	}
+
+	custrr := rr.(*dns.PrivateRR)
+	if ln := custrr.Data.Len() + len(custrr.Header().Name) + 11; ln != off {
+		t.Errorf("offset is not matching to length of Private RR: %d!=%d", off, ln)
+	}
+
+	rr1, off1, err := dns.UnpackRR(buf[:off], 0)
+	if err != nil {
+		t.Errorf("got error unpacking ISBN: %v", err)
+	}
+
+	if off1 != off {
+		t.Errorf("offset after unpacking differs: %d != %d", off1, off)
+	}
+
+	if rr1.String() != testrecord {
+		t.Errorf("record string representation did not match original %#v != %#v", rr1.String(), testrecord)
+	} else {
+		t.Log(rr1.String())
+	}
+}
+
+const TypeVERSION uint16 = 0x0F02
+
+type VERSION struct {
+	x string
+}
+
+func NewVersion() dns.PrivateRdata { return &VERSION{""} }
+
+func (rd *VERSION) String() string { return rd.x }
+func (rd *VERSION) Parse(txt []string) error {
+	rd.x = strings.TrimSpace(strings.Join(txt, " "))
+	return nil
+}
+
+func (rd *VERSION) Pack(buf []byte) (int, error) {
+	b := []byte(rd.x)
+	n := copy(buf, b)
+	if n != len(b) {
+		return n, dns.ErrBuf
+	}
+	return n, nil
+}
+
+func (rd *VERSION) Unpack(buf []byte) (int, error) {
+	rd.x = string(buf)
+	return len(buf), nil
+}
+
+func (rd *VERSION) Copy(dest dns.PrivateRdata) error {
+	isbn, ok := dest.(*VERSION)
+	if !ok {
+		return dns.ErrRdata
+	}
+	isbn.x = rd.x
+	return nil
+}
+
+func (rd *VERSION) Len() int {
+	return len([]byte(rd.x))
+}
+
+var smallzone = `$ORIGIN example.org.
+@ SOA	sns.dns.icann.org. noc.dns.icann.org. (
+		2014091518 7200 3600 1209600 3600
+)
+    A   1.2.3.4
+ok ISBN 1231-92110-12
+go VERSION (
+	1.3.1 ; comment
+)
+www ISBN 1231-92110-16
+*  CNAME @
+`
+
+func TestPrivateZoneParser(t *testing.T) {
+	dns.PrivateHandle("ISBN", TypeISBN, NewISBN)
+	dns.PrivateHandle("VERSION", TypeVERSION, NewVersion)
+	defer dns.PrivateHandleRemove(TypeISBN)
+	defer dns.PrivateHandleRemove(TypeVERSION)
+
+	r := strings.NewReader(smallzone)
+	for x := range dns.ParseZone(r, ".", "") {
+		if err := x.Error; err != nil {
+			t.Fatal(err)
+		}
+		t.Log(x.RR)
+	}
+}

rawmsg.go

@@ -0,0 +1,95 @@
+package dns
+
+// These raw* functions do not use reflection, they directly set the values
+// in the buffer. There are faster than their reflection counterparts.
+
+// RawSetId sets the message id in buf.
+func rawSetId(msg []byte, i uint16) bool {
+	if len(msg) < 2 {
+		return false
+	}
+	msg[0], msg[1] = packUint16(i)
+	return true
+}
+
+// rawSetQuestionLen sets the length of the question section.
+func rawSetQuestionLen(msg []byte, i uint16) bool {
+	if len(msg) < 6 {
+		return false
+	}
+	msg[4], msg[5] = packUint16(i)
+	return true
+}
+
+// rawSetAnswerLen sets the length of the answer section.
+func rawSetAnswerLen(msg []byte, i uint16) bool {
+	if len(msg) < 8 {
+		return false
+	}
+	msg[6], msg[7] = packUint16(i)
+	return true
+}
+
+// rawSetsNsLen sets the length of the authority section.
+func rawSetNsLen(msg []byte, i uint16) bool {
+	if len(msg) < 10 {
+		return false
+	}
+	msg[8], msg[9] = packUint16(i)
+	return true
+}
+
+// rawSetExtraLen sets the length of the additional section.
+func rawSetExtraLen(msg []byte, i uint16) bool {
+	if len(msg) < 12 {
+		return false
+	}
+	msg[10], msg[11] = packUint16(i)
+	return true
+}
+
+// rawSetRdlength sets the rdlength in the header of
+// the RR. The offset 'off' must be positioned at the
+// start of the header of the RR, 'end' must be the
+// end of the RR.
+func rawSetRdlength(msg []byte, off, end int) bool {
+	l := len(msg)
+Loop:
+	for {
+		if off+1 > l {
+			return false
+		}
+		c := int(msg[off])
+		off++
+		switch c & 0xC0 {
+		case 0x00:
+			if c == 0x00 {
+				// End of the domainname
+				break Loop
+			}
+			if off+c > l {
+				return false
+			}
+			off += c
+
+		case 0xC0:
+			// pointer, next byte included, ends domainname
+			off++
+			break Loop
+		}
+	}
+	// The domainname has been seen, we at the start of the fixed part in the header.
+	// Type is 2 bytes, class is 2 bytes, ttl 4 and then 2 bytes for the length.
+	off += 2 + 2 + 4
+	if off+2 > l {
+		return false
+	}
+	//off+1 is the end of the header, 'end' is the end of the rr
+	//so 'end' - 'off+2' is the length of the rdata
+	rdatalen := end - (off + 2)
+	if rdatalen > 0xFFFF {
+		return false
+	}
+	msg[off], msg[off+1] = packUint16(uint16(rdatalen))
+	return true
+}

remote_test.go

@@ -0,0 +1,19 @@
+package dns
+
+import "testing"
+
+const LinodeAddr = "176.58.119.54:53"
+
+func TestClientRemote(t *testing.T) {
+	m := new(Msg)
+	m.SetQuestion("go.dns.miek.nl.", TypeTXT)
+
+	c := new(Client)
+	r, _, err := c.Exchange(m, LinodeAddr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	if r != nil && r.Rcode != RcodeSuccess {
+		t.Errorf("failed to get an valid answer\n%v", r)
+	}
+}

sanitize.go

@@ -0,0 +1,84 @@
+package dns
+
+// Dedup removes identical RRs from rrs. It preserves the original ordering.
+// The lowest TTL of any duplicates is used in the remaining one. Dedup modifies
+// rrs.
+// m is used to store the RRs temporay. If it is nil a new map will be allocated.
+func Dedup(rrs []RR, m map[string]RR) []RR {
+	if m == nil {
+		m = make(map[string]RR)
+	}
+	// Save the keys, so we don't have to call normalizedString twice.
+	keys := make([]*string, 0, len(rrs))
+
+	for _, r := range rrs {
+		key := normalizedString(r)
+		keys = append(keys, &key)
+		if _, ok := m[key]; ok {
+			// Shortest TTL wins.
+			if m[key].Header().Ttl > r.Header().Ttl {
+				m[key].Header().Ttl = r.Header().Ttl
+			}
+			continue
+		}
+
+		m[key] = r
+	}
+	// If the length of the result map equals the amount of RRs we got,
+	// it means they were all different. We can then just return the original rrset.
+	if len(m) == len(rrs) {
+		return rrs
+	}
+
+	j := 0
+	for i, r := range rrs {
+		// If keys[i] lives in the map, we should copy and remove it.
+		if _, ok := m[*keys[i]]; ok {
+			delete(m, *keys[i])
+			rrs[j] = r
+			j++
+		}
+
+		if len(m) == 0 {
+			break
+		}
+	}
+
+	return rrs[:j]
+}
+
+// normalizedString returns a normalized string from r. The TTL
+// is removed and the domain name is lowercased. We go from this:
+// DomainName<TAB>TTL<TAB>CLASS<TAB>TYPE<TAB>RDATA to:
+// lowercasename<TAB>CLASS<TAB>TYPE...
+func normalizedString(r RR) string {
+	// A string Go DNS makes has: domainname<TAB>TTL<TAB>...
+	b := []byte(r.String())
+
+	// find the first non-escaped tab, then another, so we capture where the TTL lives.
+	esc := false
+	ttlStart, ttlEnd := 0, 0
+	for i := 0; i < len(b) && ttlEnd == 0; i++ {
+		switch {
+		case b[i] == '\\':
+			esc = !esc
+		case b[i] == '\t' && !esc:
+			if ttlStart == 0 {
+				ttlStart = i
+				continue
+			}
+			if ttlEnd == 0 {
+				ttlEnd = i
+			}
+		case b[i] >= 'A' && b[i] <= 'Z' && !esc:
+			b[i] += 32
+		default:
+			esc = false
+		}
+	}
+
+	// remove TTL.
+	copy(b[ttlStart:], b[ttlEnd:])
+	cut := ttlEnd - ttlStart
+	return string(b[:len(b)-cut])
+}

sanitize_test.go

@@ -0,0 +1,85 @@
+package dns
+
+import "testing"
+
+func TestDedup(t *testing.T) {
+	// make it []string
+	testcases := map[[3]RR][]string{
+		[...]RR{
+			newRR(t, "mIek.nl. IN A 127.0.0.1"),
+			newRR(t, "mieK.nl. IN A 127.0.0.1"),
+			newRR(t, "miek.Nl. IN A 127.0.0.1"),
+		}: {"mIek.nl.\t3600\tIN\tA\t127.0.0.1"},
+		[...]RR{
+			newRR(t, "miEk.nl. 2000 IN A 127.0.0.1"),
+			newRR(t, "mieK.Nl. 1000 IN A 127.0.0.1"),
+			newRR(t, "Miek.nL. 500 IN A 127.0.0.1"),
+		}: {"miEk.nl.\t500\tIN\tA\t127.0.0.1"},
+		[...]RR{
+			newRR(t, "miek.nl. IN A 127.0.0.1"),
+			newRR(t, "miek.nl. CH A 127.0.0.1"),
+			newRR(t, "miek.nl. IN A 127.0.0.1"),
+		}: {"miek.nl.\t3600\tIN\tA\t127.0.0.1",
+			"miek.nl.\t3600\tCH\tA\t127.0.0.1",
+		},
+		[...]RR{
+			newRR(t, "miek.nl. CH A 127.0.0.1"),
+			newRR(t, "miek.nl. IN A 127.0.0.1"),
+			newRR(t, "miek.de. IN A 127.0.0.1"),
+		}: {"miek.nl.\t3600\tCH\tA\t127.0.0.1",
+			"miek.nl.\t3600\tIN\tA\t127.0.0.1",
+			"miek.de.\t3600\tIN\tA\t127.0.0.1",
+		},
+		[...]RR{
+			newRR(t, "miek.de. IN A 127.0.0.1"),
+			newRR(t, "miek.nl. 200 IN A 127.0.0.1"),
+			newRR(t, "miek.nl. 300 IN A 127.0.0.1"),
+		}: {"miek.de.\t3600\tIN\tA\t127.0.0.1",
+			"miek.nl.\t200\tIN\tA\t127.0.0.1",
+		},
+	}
+
+	for rr, expected := range testcases {
+		out := Dedup([]RR{rr[0], rr[1], rr[2]}, nil)
+		for i, o := range out {
+			if o.String() != expected[i] {
+				t.Fatalf("expected %v, got %v", expected[i], o.String())
+			}
+		}
+	}
+}
+
+func BenchmarkDedup(b *testing.B) {
+	rrs := []RR{
+		newRR(nil, "miEk.nl. 2000 IN A 127.0.0.1"),
+		newRR(nil, "mieK.Nl. 1000 IN A 127.0.0.1"),
+		newRR(nil, "Miek.nL. 500 IN A 127.0.0.1"),
+	}
+	m := make(map[string]RR)
+	for i := 0; i < b.N; i++ {
+		Dedup(rrs, m)
+	}
+}
+
+func TestNormalizedString(t *testing.T) {
+	tests := map[RR]string{
+		newRR(t, "mIEk.Nl. 3600 IN A 127.0.0.1"):     "miek.nl.\tIN\tA\t127.0.0.1",
+		newRR(t, "m\\ iek.nL. 3600 IN A 127.0.0.1"):  "m\\ iek.nl.\tIN\tA\t127.0.0.1",
+		newRR(t, "m\\\tIeK.nl. 3600 in A 127.0.0.1"): "m\\tiek.nl.\tIN\tA\t127.0.0.1",
+	}
+	for tc, expected := range tests {
+		n := normalizedString(tc)
+		if n != expected {
+			t.Logf("expected %s, got %s", expected, n)
+			t.Fail()
+		}
+	}
+}
+
+func newRR(t *testing.T, s string) RR {
+	r, e := NewRR(s)
+	if e != nil {
+		t.Logf("newRR: %s", e)
+	}
+	return r
+}

scanner.go

@@ -0,0 +1,43 @@
+package dns
+
+// Implement a simple scanner, return a byte stream from an io reader.
+
+import (
+	"bufio"
+	"io"
+	"text/scanner"
+)
+
+type scan struct {
+	src      *bufio.Reader
+	position scanner.Position
+	eof      bool // Have we just seen a eof
+}
+
+func scanInit(r io.Reader) *scan {
+	s := new(scan)
+	s.src = bufio.NewReader(r)
+	s.position.Line = 1
+	return s
+}
+
+// tokenText returns the next byte from the input
+func (s *scan) tokenText() (byte, error) {
+	c, err := s.src.ReadByte()
+	if err != nil {
+		return c, err
+	}
+	// delay the newline handling until the next token is delivered,
+	// fixes off-by-one errors when reporting a parse error.
+	if s.eof == true {
+		s.position.Line++
+		s.position.Column = 0
+		s.eof = false
+	}
+	if c == '\n' {
+		s.eof = true
+		return c, nil
+	}
+	s.position.Column++
+	return c, nil
+}

server.go

@@ -0,0 +1,731 @@
+// DNS server implementation.
+
+package dns
+
+import (
+	"bytes"
+	"crypto/tls"
+	"io"
+	"net"
+	"sync"
+	"time"
+)
+
+// Maximum number of TCP queries before we close the socket.
+const maxTCPQueries = 128
+
+// Handler is implemented by any value that implements ServeDNS.
+type Handler interface {
+	ServeDNS(w ResponseWriter, r *Msg)
+}
+
+// A ResponseWriter interface is used by an DNS handler to
+// construct an DNS response.
+type ResponseWriter interface {
+	// LocalAddr returns the net.Addr of the server
+	LocalAddr() net.Addr
+	// RemoteAddr returns the net.Addr of the client that sent the current request.
+	RemoteAddr() net.Addr
+	// WriteMsg writes a reply back to the client.
+	WriteMsg(*Msg) error
+	// Write writes a raw buffer back to the client.
+	Write([]byte) (int, error)
+	// Close closes the connection.
+	Close() error
+	// TsigStatus returns the status of the Tsig.
+	TsigStatus() error
+	// TsigTimersOnly sets the tsig timers only boolean.
+	TsigTimersOnly(bool)
+	// Hijack lets the caller take over the connection.
+	// After a call to Hijack(), the DNS package will not do anything with the connection.
+	Hijack()
+}
+
+type response struct {
+	hijacked       bool // connection has been hijacked by handler
+	tsigStatus     error
+	tsigTimersOnly bool
+	tsigRequestMAC string
+	tsigSecret     map[string]string // the tsig secrets
+	udp            *net.UDPConn      // i/o connection if UDP was used
+	tcp            net.Conn          // i/o connection if TCP was used
+	udpSession     *SessionUDP       // oob data to get egress interface right
+	remoteAddr     net.Addr          // address of the client
+	writer         Writer            // writer to output the raw DNS bits
+}
+
+// ServeMux is an DNS request multiplexer. It matches the
+// zone name of each incoming request against a list of
+// registered patterns add calls the handler for the pattern
+// that most closely matches the zone name. ServeMux is DNSSEC aware, meaning
+// that queries for the DS record are redirected to the parent zone (if that
+// is also registered), otherwise the child gets the query.
+// ServeMux is also safe for concurrent access from multiple goroutines.
+type ServeMux struct {
+	z map[string]Handler
+	m *sync.RWMutex
+}
+
+// NewServeMux allocates and returns a new ServeMux.
+func NewServeMux() *ServeMux { return &ServeMux{z: make(map[string]Handler), m: new(sync.RWMutex)} }
+
+// DefaultServeMux is the default ServeMux used by Serve.
+var DefaultServeMux = NewServeMux()
+
+// The HandlerFunc type is an adapter to allow the use of
+// ordinary functions as DNS handlers.  If f is a function
+// with the appropriate signature, HandlerFunc(f) is a
+// Handler object that calls f.
+type HandlerFunc func(ResponseWriter, *Msg)
+
+// ServeDNS calls f(w, r).
+func (f HandlerFunc) ServeDNS(w ResponseWriter, r *Msg) {
+	f(w, r)
+}
+
+// HandleFailed returns a HandlerFunc that returns SERVFAIL for every request it gets.
+func HandleFailed(w ResponseWriter, r *Msg) {
+	m := new(Msg)
+	m.SetRcode(r, RcodeServerFailure)
+	// does not matter if this write fails
+	w.WriteMsg(m)
+}
+
+func failedHandler() Handler { return HandlerFunc(HandleFailed) }
+
+// ListenAndServe Starts a server on address and network specified Invoke handler
+// for incoming queries.
+func ListenAndServe(addr string, network string, handler Handler) error {
+	server := &Server{Addr: addr, Net: network, Handler: handler}
+	return server.ListenAndServe()
+}
+
+// ListenAndServeTLS acts like http.ListenAndServeTLS, more information in
+// http://golang.org/pkg/net/http/#ListenAndServeTLS
+func ListenAndServeTLS(addr, certFile, keyFile string, handler Handler) error {
+	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		return err
+	}
+
+	config := tls.Config{
+		Certificates: []tls.Certificate{cert},
+	}
+
+	server := &Server{
+		Addr:      addr,
+		Net:       "tcp-tls",
+		TLSConfig: &config,
+		Handler:   handler,
+	}
+
+	return server.ListenAndServe()
+}
+
+// ActivateAndServe activates a server with a listener from systemd,
+// l and p should not both be non-nil.
+// If both l and p are not nil only p will be used.
+// Invoke handler for incoming queries.
+func ActivateAndServe(l net.Listener, p net.PacketConn, handler Handler) error {
+	server := &Server{Listener: l, PacketConn: p, Handler: handler}
+	return server.ActivateAndServe()
+}
+
+func (mux *ServeMux) match(q string, t uint16) Handler {
+	mux.m.RLock()
+	defer mux.m.RUnlock()
+	var handler Handler
+	b := make([]byte, len(q)) // worst case, one label of length q
+	off := 0
+	end := false
+	for {
+		l := len(q[off:])
+		for i := 0; i < l; i++ {
+			b[i] = q[off+i]
+			if b[i] >= 'A' && b[i] <= 'Z' {
+				b[i] |= ('a' - 'A')
+			}
+		}
+		if h, ok := mux.z[string(b[:l])]; ok { // 'causes garbage, might want to change the map key
+			if t != TypeDS {
+				return h
+			}
+			// Continue for DS to see if we have a parent too, if so delegeate to the parent
+			handler = h
+		}
+		off, end = NextLabel(q, off)
+		if end {
+			break
+		}
+	}
+	// Wildcard match, if we have found nothing try the root zone as a last resort.
+	if h, ok := mux.z["."]; ok {
+		return h
+	}
+	return handler
+}
+
+// Handle adds a handler to the ServeMux for pattern.
+func (mux *ServeMux) Handle(pattern string, handler Handler) {
+	if pattern == "" {
+		panic("dns: invalid pattern " + pattern)
+	}
+	mux.m.Lock()
+	mux.z[Fqdn(pattern)] = handler
+	mux.m.Unlock()
+}
+
+// HandleFunc adds a handler function to the ServeMux for pattern.
+func (mux *ServeMux) HandleFunc(pattern string, handler func(ResponseWriter, *Msg)) {
+	mux.Handle(pattern, HandlerFunc(handler))
+}
+
+// HandleRemove deregistrars the handler specific for pattern from the ServeMux.
+func (mux *ServeMux) HandleRemove(pattern string) {
+	if pattern == "" {
+		panic("dns: invalid pattern " + pattern)
+	}
+	mux.m.Lock()
+	delete(mux.z, Fqdn(pattern))
+	mux.m.Unlock()
+}
+
+// ServeDNS dispatches the request to the handler whose
+// pattern most closely matches the request message. If DefaultServeMux
+// is used the correct thing for DS queries is done: a possible parent
+// is sought.
+// If no handler is found a standard SERVFAIL message is returned
+// If the request message does not have exactly one question in the
+// question section a SERVFAIL is returned, unlesss Unsafe is true.
+func (mux *ServeMux) ServeDNS(w ResponseWriter, request *Msg) {
+	var h Handler
+	if len(request.Question) < 1 { // allow more than one question
+		h = failedHandler()
+	} else {
+		if h = mux.match(request.Question[0].Name, request.Question[0].Qtype); h == nil {
+			h = failedHandler()
+		}
+	}
+	h.ServeDNS(w, request)
+}
+
+// Handle registers the handler with the given pattern
+// in the DefaultServeMux. The documentation for
+// ServeMux explains how patterns are matched.
+func Handle(pattern string, handler Handler) { DefaultServeMux.Handle(pattern, handler) }
+
+// HandleRemove deregisters the handle with the given pattern
+// in the DefaultServeMux.
+func HandleRemove(pattern string) { DefaultServeMux.HandleRemove(pattern) }
+
+// HandleFunc registers the handler function with the given pattern
+// in the DefaultServeMux.
+func HandleFunc(pattern string, handler func(ResponseWriter, *Msg)) {
+	DefaultServeMux.HandleFunc(pattern, handler)
+}
+
+// Writer writes raw DNS messages; each call to Write should send an entire message.
+type Writer interface {
+	io.Writer
+}
+
+// Reader reads raw DNS messages; each call to ReadTCP or ReadUDP should return an entire message.
+type Reader interface {
+	// ReadTCP reads a raw message from a TCP connection. Implementations may alter
+	// connection properties, for example the read-deadline.
+	ReadTCP(conn net.Conn, timeout time.Duration) ([]byte, error)
+	// ReadUDP reads a raw message from a UDP connection. Implementations may alter
+	// connection properties, for example the read-deadline.
+	ReadUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *SessionUDP, error)
+}
+
+// defaultReader is an adapter for the Server struct that implements the Reader interface
+// using the readTCP and readUDP func of the embedded Server.
+type defaultReader struct {
+	*Server
+}
+
+func (dr *defaultReader) ReadTCP(conn net.Conn, timeout time.Duration) ([]byte, error) {
+	return dr.readTCP(conn, timeout)
+}
+
+func (dr *defaultReader) ReadUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *SessionUDP, error) {
+	return dr.readUDP(conn, timeout)
+}
+
+// DecorateReader is a decorator hook for extending or supplanting the functionality of a Reader.
+// Implementations should never return a nil Reader.
+type DecorateReader func(Reader) Reader
+
+// DecorateWriter is a decorator hook for extending or supplanting the functionality of a Writer.
+// Implementations should never return a nil Writer.
+type DecorateWriter func(Writer) Writer
+
+// A Server defines parameters for running an DNS server.
+type Server struct {
+	// Address to listen on, ":dns" if empty.
+	Addr string
+	// if "tcp" or "tcp-tls" (DNS over TLS) it will invoke a TCP listener, otherwise an UDP one
+	Net string
+	// TCP Listener to use, this is to aid in systemd's socket activation.
+	Listener net.Listener
+	// TLS connection configuration
+	TLSConfig *tls.Config
+	// UDP "Listener" to use, this is to aid in systemd's socket activation.
+	PacketConn net.PacketConn
+	// Handler to invoke, dns.DefaultServeMux if nil.
+	Handler Handler
+	// Default buffer size to use to read incoming UDP messages. If not set
+	// it defaults to MinMsgSize (512 B).
+	UDPSize int
+	// The net.Conn.SetReadTimeout value for new connections, defaults to 2 * time.Second.
+	ReadTimeout time.Duration
+	// The net.Conn.SetWriteTimeout value for new connections, defaults to 2 * time.Second.
+	WriteTimeout time.Duration
+	// TCP idle timeout for multiple queries, if nil, defaults to 8 * time.Second (RFC 5966).
+	IdleTimeout func() time.Duration
+	// Secret(s) for Tsig map[<zonename>]<base64 secret>.
+	TsigSecret map[string]string
+	// Unsafe instructs the server to disregard any sanity checks and directly hand the message to
+	// the handler. It will specifically not check if the query has the QR bit not set.
+	Unsafe bool
+	// If NotifyStartedFunc is set it is called once the server has started listening.
+	NotifyStartedFunc func()
+	// DecorateReader is optional, allows customization of the process that reads raw DNS messages.
+	DecorateReader DecorateReader
+	// DecorateWriter is optional, allows customization of the process that writes raw DNS messages.
+	DecorateWriter DecorateWriter
+
+	// Graceful shutdown handling
+
+	inFlight sync.WaitGroup
+
+	lock    sync.RWMutex
+	started bool
+}
+
+// ListenAndServe starts a nameserver on the configured address in *Server.
+func (srv *Server) ListenAndServe() error {
+	srv.lock.Lock()
+	defer srv.lock.Unlock()
+	if srv.started {
+		return &Error{err: "server already started"}
+	}
+	addr := srv.Addr
+	if addr == "" {
+		addr = ":domain"
+	}
+	if srv.UDPSize == 0 {
+		srv.UDPSize = MinMsgSize
+	}
+	switch srv.Net {
+	case "tcp", "tcp4", "tcp6":
+		a, e := net.ResolveTCPAddr(srv.Net, addr)
+		if e != nil {
+			return e
+		}
+		l, e := net.ListenTCP(srv.Net, a)
+		if e != nil {
+			return e
+		}
+		srv.Listener = l
+		srv.started = true
+		srv.lock.Unlock()
+		e = srv.serveTCP(l)
+		srv.lock.Lock() // to satisfy the defer at the top
+		return e
+	case "tcp-tls", "tcp4-tls", "tcp6-tls":
+		network := "tcp"
+		if srv.Net == "tcp4-tls" {
+			network = "tcp4"
+		} else if srv.Net == "tcp6" {
+			network = "tcp6"
+		}
+
+		l, e := tls.Listen(network, addr, srv.TLSConfig)
+		if e != nil {
+			return e
+		}
+		srv.Listener = l
+		srv.started = true
+		srv.lock.Unlock()
+		e = srv.serveTCP(l)
+		srv.lock.Lock() // to satisfy the defer at the top
+		return e
+	case "udp", "udp4", "udp6":
+		a, e := net.ResolveUDPAddr(srv.Net, addr)
+		if e != nil {
+			return e
+		}
+		l, e := net.ListenUDP(srv.Net, a)
+		if e != nil {
+			return e
+		}
+		if e := setUDPSocketOptions(l); e != nil {
+			return e
+		}
+		srv.PacketConn = l
+		srv.started = true
+		srv.lock.Unlock()
+		e = srv.serveUDP(l)
+		srv.lock.Lock() // to satisfy the defer at the top
+		return e
+	}
+	return &Error{err: "bad network"}
+}
+
+// ActivateAndServe starts a nameserver with the PacketConn or Listener
+// configured in *Server. Its main use is to start a server from systemd.
+func (srv *Server) ActivateAndServe() error {
+	srv.lock.Lock()
+	defer srv.lock.Unlock()
+	if srv.started {
+		return &Error{err: "server already started"}
+	}
+	pConn := srv.PacketConn
+	l := srv.Listener
+	if pConn != nil {
+		if srv.UDPSize == 0 {
+			srv.UDPSize = MinMsgSize
+		}
+		if t, ok := pConn.(*net.UDPConn); ok {
+			if e := setUDPSocketOptions(t); e != nil {
+				return e
+			}
+			srv.started = true
+			srv.lock.Unlock()
+			e := srv.serveUDP(t)
+			srv.lock.Lock() // to satisfy the defer at the top
+			return e
+		}
+	}
+	if l != nil {
+		srv.started = true
+		srv.lock.Unlock()
+		e := srv.serveTCP(l)
+		srv.lock.Lock() // to satisfy the defer at the top
+		return e
+	}
+	return &Error{err: "bad listeners"}
+}
+
+// Shutdown gracefully shuts down a server. After a call to Shutdown, ListenAndServe and
+// ActivateAndServe will return. All in progress queries are completed before the server
+// is taken down. If the Shutdown is taking longer than the reading timeout an error
+// is returned.
+func (srv *Server) Shutdown() error {
+	srv.lock.Lock()
+	if !srv.started {
+		srv.lock.Unlock()
+		return &Error{err: "server not started"}
+	}
+	srv.started = false
+	srv.lock.Unlock()
+
+	if srv.PacketConn != nil {
+		srv.PacketConn.Close()
+	}
+	if srv.Listener != nil {
+		srv.Listener.Close()
+	}
+
+	fin := make(chan bool)
+	go func() {
+		srv.inFlight.Wait()
+		fin <- true
+	}()
+
+	select {
+	case <-time.After(srv.getReadTimeout()):
+		return &Error{err: "server shutdown is pending"}
+	case <-fin:
+		return nil
+	}
+}
+
+// getReadTimeout is a helper func to use system timeout if server did not intend to change it.
+func (srv *Server) getReadTimeout() time.Duration {
+	rtimeout := dnsTimeout
+	if srv.ReadTimeout != 0 {
+		rtimeout = srv.ReadTimeout
+	}
+	return rtimeout
+}
+
+// serveTCP starts a TCP listener for the server.
+// Each request is handled in a separate goroutine.
+func (srv *Server) serveTCP(l net.Listener) error {
+	defer l.Close()
+
+	if srv.NotifyStartedFunc != nil {
+		srv.NotifyStartedFunc()
+	}
+
+	reader := Reader(&defaultReader{srv})
+	if srv.DecorateReader != nil {
+		reader = srv.DecorateReader(reader)
+	}
+
+	handler := srv.Handler
+	if handler == nil {
+		handler = DefaultServeMux
+	}
+	rtimeout := srv.getReadTimeout()
+	// deadline is not used here
+	for {
+		rw, e := l.Accept()
+		if e != nil {
+			if neterr, ok := e.(net.Error); ok && neterr.Temporary() {
+				continue
+			}
+			return e
+		}
+		m, e := reader.ReadTCP(rw, rtimeout)
+		srv.lock.RLock()
+		if !srv.started {
+			srv.lock.RUnlock()
+			return nil
+		}
+		srv.lock.RUnlock()
+		if e != nil {
+			continue
+		}
+		srv.inFlight.Add(1)
+		go srv.serve(rw.RemoteAddr(), handler, m, nil, nil, rw)
+	}
+}
+
+// serveUDP starts a UDP listener for the server.
+// Each request is handled in a separate goroutine.
+func (srv *Server) serveUDP(l *net.UDPConn) error {
+	defer l.Close()
+
+	if srv.NotifyStartedFunc != nil {
+		srv.NotifyStartedFunc()
+	}
+
+	reader := Reader(&defaultReader{srv})
+	if srv.DecorateReader != nil {
+		reader = srv.DecorateReader(reader)
+	}
+
+	handler := srv.Handler
+	if handler == nil {
+		handler = DefaultServeMux
+	}
+	rtimeout := srv.getReadTimeout()
+	// deadline is not used here
+	for {
+		m, s, e := reader.ReadUDP(l, rtimeout)
+		srv.lock.RLock()
+		if !srv.started {
+			srv.lock.RUnlock()
+			return nil
+		}
+		srv.lock.RUnlock()
+		if e != nil {
+			continue
+		}
+		srv.inFlight.Add(1)
+		go srv.serve(s.RemoteAddr(), handler, m, l, s, nil)
+	}
+}
+
+// Serve a new connection.
+func (srv *Server) serve(a net.Addr, h Handler, m []byte, u *net.UDPConn, s *SessionUDP, t net.Conn) {
+	defer srv.inFlight.Done()
+
+	w := &response{tsigSecret: srv.TsigSecret, udp: u, tcp: t, remoteAddr: a, udpSession: s}
+	if srv.DecorateWriter != nil {
+		w.writer = srv.DecorateWriter(w)
+	} else {
+		w.writer = w
+	}
+
+	q := 0 // counter for the amount of TCP queries we get
+
+	reader := Reader(&defaultReader{srv})
+	if srv.DecorateReader != nil {
+		reader = srv.DecorateReader(reader)
+	}
+Redo:
+	req := new(Msg)
+	err := req.Unpack(m)
+	if err != nil { // Send a FormatError back
+		x := new(Msg)
+		x.SetRcodeFormatError(req)
+		w.WriteMsg(x)
+		goto Exit
+	}
+	if !srv.Unsafe && req.Response {
+		goto Exit
+	}
+
+	w.tsigStatus = nil
+	if w.tsigSecret != nil {
+		if t := req.IsTsig(); t != nil {
+			secret := t.Hdr.Name
+			if _, ok := w.tsigSecret[secret]; !ok {
+				w.tsigStatus = ErrKeyAlg
+			}
+			w.tsigStatus = TsigVerify(m, w.tsigSecret[secret], "", false)
+			w.tsigTimersOnly = false
+			w.tsigRequestMAC = req.Extra[len(req.Extra)-1].(*TSIG).MAC
+		}
+	}
+	h.ServeDNS(w, req) // Writes back to the client
+
+Exit:
+	if w.tcp == nil {
+		return
+	}
+	// TODO(miek): make this number configurable?
+	if q > maxTCPQueries { // close socket after this many queries
+		w.Close()
+		return
+	}
+
+	if w.hijacked {
+		return // client calls Close()
+	}
+	if u != nil { // UDP, "close" and return
+		w.Close()
+		return
+	}
+	idleTimeout := tcpIdleTimeout
+	if srv.IdleTimeout != nil {
+		idleTimeout = srv.IdleTimeout()
+	}
+	m, e := reader.ReadTCP(w.tcp, idleTimeout)
+	if e == nil {
+		q++
+		goto Redo
+	}
+	w.Close()
+	return
+}
+
+func (srv *Server) readTCP(conn net.Conn, timeout time.Duration) ([]byte, error) {
+	conn.SetReadDeadline(time.Now().Add(timeout))
+	l := make([]byte, 2)
+	n, err := conn.Read(l)
+	if err != nil || n != 2 {
+		if err != nil {
+			return nil, err
+		}
+		return nil, ErrShortRead
+	}
+	length, _ := unpackUint16(l, 0)
+	if length == 0 {
+		return nil, ErrShortRead
+	}
+	m := make([]byte, int(length))
+	n, err = conn.Read(m[:int(length)])
+	if err != nil || n == 0 {
+		if err != nil {
+			return nil, err
+		}
+		return nil, ErrShortRead
+	}
+	i := n
+	for i < int(length) {
+		j, err := conn.Read(m[i:int(length)])
+		if err != nil {
+			return nil, err
+		}
+		i += j
+	}
+	n = i
+	m = m[:n]
+	return m, nil
+}
+
+func (srv *Server) readUDP(conn *net.UDPConn, timeout time.Duration) ([]byte, *SessionUDP, error) {
+	conn.SetReadDeadline(time.Now().Add(timeout))
+	m := make([]byte, srv.UDPSize)
+	n, s, e := ReadFromSessionUDP(conn, m)
+	if e != nil || n == 0 {
+		if e != nil {
+			return nil, nil, e
+		}
+		return nil, nil, ErrShortRead
+	}
+	m = m[:n]
+	return m, s, nil
+}
+
+// WriteMsg implements the ResponseWriter.WriteMsg method.
+func (w *response) WriteMsg(m *Msg) (err error) {
+	var data []byte
+	if w.tsigSecret != nil { // if no secrets, dont check for the tsig (which is a longer check)
+		if t := m.IsTsig(); t != nil {
+			data, w.tsigRequestMAC, err = TsigGenerate(m, w.tsigSecret[t.Hdr.Name], w.tsigRequestMAC, w.tsigTimersOnly)
+			if err != nil {
+				return err
+			}
+			_, err = w.writer.Write(data)
+			return err
+		}
+	}
+	data, err = m.Pack()
+	if err != nil {
+		return err
+	}
+	_, err = w.writer.Write(data)
+	return err
+}
+
+// Write implements the ResponseWriter.Write method.
+func (w *response) Write(m []byte) (int, error) {
+	switch {
+	case w.udp != nil:
+		n, err := WriteToSessionUDP(w.udp, m, w.udpSession)
+		return n, err
+	case w.tcp != nil:
+		lm := len(m)
+		if lm < 2 {
+			return 0, io.ErrShortBuffer
+		}
+		if lm > MaxMsgSize {
+			return 0, &Error{err: "message too large"}
+		}
+		l := make([]byte, 2, 2+lm)
+		l[0], l[1] = packUint16(uint16(lm))
+		m = append(l, m...)
+
+		n, err := io.Copy(w.tcp, bytes.NewReader(m))
+		return int(n), err
+	}
+	panic("not reached")
+}
+
+// LocalAddr implements the ResponseWriter.LocalAddr method.
+func (w *response) LocalAddr() net.Addr {
+	if w.tcp != nil {
+		return w.tcp.LocalAddr()
+	}
+	return w.udp.LocalAddr()
+}
+
+// RemoteAddr implements the ResponseWriter.RemoteAddr method.
+func (w *response) RemoteAddr() net.Addr { return w.remoteAddr }
+
+// TsigStatus implements the ResponseWriter.TsigStatus method.
+func (w *response) TsigStatus() error { return w.tsigStatus }
+
+// TsigTimersOnly implements the ResponseWriter.TsigTimersOnly method.
+func (w *response) TsigTimersOnly(b bool) { w.tsigTimersOnly = b }
+
+// Hijack implements the ResponseWriter.Hijack method.
+func (w *response) Hijack() { w.hijacked = true }
+
+// Close implements the ResponseWriter.Close method
+func (w *response) Close() error {
+	// Can't close the udp conn, as that is actually the listener.
+	if w.tcp != nil {
+		e := w.tcp.Close()
+		w.tcp = nil
+		return e
+	}
+	return nil
+}

server_test.go

@@ -0,0 +1,679 @@
+package dns
+
+import (
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net"
+	"runtime"
+	"sync"
+	"testing"
+	"time"
+)
+
+func HelloServer(w ResponseWriter, req *Msg) {
+	m := new(Msg)
+	m.SetReply(req)
+
+	m.Extra = make([]RR, 1)
+	m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	w.WriteMsg(m)
+}
+
+func HelloServerBadId(w ResponseWriter, req *Msg) {
+	m := new(Msg)
+	m.SetReply(req)
+	m.Id++
+
+	m.Extra = make([]RR, 1)
+	m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	w.WriteMsg(m)
+}
+
+func AnotherHelloServer(w ResponseWriter, req *Msg) {
+	m := new(Msg)
+	m.SetReply(req)
+
+	m.Extra = make([]RR, 1)
+	m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello example"}}
+	w.WriteMsg(m)
+}
+
+func RunLocalUDPServer(laddr string) (*Server, string, error) {
+	server, l, _, err := RunLocalUDPServerWithFinChan(laddr)
+
+	return server, l, err
+}
+
+func RunLocalUDPServerWithFinChan(laddr string) (*Server, string, chan struct{}, error) {
+	pc, err := net.ListenPacket("udp", laddr)
+	if err != nil {
+		return nil, "", nil, err
+	}
+	server := &Server{PacketConn: pc, ReadTimeout: time.Hour, WriteTimeout: time.Hour}
+
+	waitLock := sync.Mutex{}
+	waitLock.Lock()
+	server.NotifyStartedFunc = waitLock.Unlock
+
+	fin := make(chan struct{}, 0)
+
+	go func() {
+		server.ActivateAndServe()
+		close(fin)
+		pc.Close()
+	}()
+
+	waitLock.Lock()
+	return server, pc.LocalAddr().String(), fin, nil
+}
+
+func RunLocalUDPServerUnsafe(laddr string) (*Server, string, error) {
+	pc, err := net.ListenPacket("udp", laddr)
+	if err != nil {
+		return nil, "", err
+	}
+	server := &Server{PacketConn: pc, Unsafe: true,
+		ReadTimeout: time.Hour, WriteTimeout: time.Hour}
+
+	waitLock := sync.Mutex{}
+	waitLock.Lock()
+	server.NotifyStartedFunc = waitLock.Unlock
+
+	go func() {
+		server.ActivateAndServe()
+		pc.Close()
+	}()
+
+	waitLock.Lock()
+	return server, pc.LocalAddr().String(), nil
+}
+
+func RunLocalTCPServer(laddr string) (*Server, string, error) {
+	l, err := net.Listen("tcp", laddr)
+	if err != nil {
+		return nil, "", err
+	}
+
+	server := &Server{Listener: l, ReadTimeout: time.Hour, WriteTimeout: time.Hour}
+
+	waitLock := sync.Mutex{}
+	waitLock.Lock()
+	server.NotifyStartedFunc = waitLock.Unlock
+
+	go func() {
+		server.ActivateAndServe()
+		l.Close()
+	}()
+
+	waitLock.Lock()
+	return server, l.Addr().String(), nil
+}
+
+func RunLocalTLSServer(laddr string, config *tls.Config) (*Server, string, error) {
+	l, err := tls.Listen("tcp", laddr, config)
+	if err != nil {
+		return nil, "", err
+	}
+
+	server := &Server{Listener: l, ReadTimeout: time.Hour, WriteTimeout: time.Hour}
+
+	waitLock := sync.Mutex{}
+	waitLock.Lock()
+	server.NotifyStartedFunc = waitLock.Unlock
+
+	go func() {
+		server.ActivateAndServe()
+		l.Close()
+	}()
+
+	waitLock.Lock()
+	return server, l.Addr().String(), nil
+}
+
+func TestServing(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServer)
+	HandleFunc("example.com.", AnotherHelloServer)
+	defer HandleRemove("miek.nl.")
+	defer HandleRemove("example.com.")
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	c := new(Client)
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeTXT)
+	r, _, err := c.Exchange(m, addrstr)
+	if err != nil || len(r.Extra) == 0 {
+		t.Fatal("failed to exchange miek.nl", err)
+	}
+	txt := r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello world" {
+		t.Error("unexpected result for miek.nl", txt, "!= Hello world")
+	}
+
+	m.SetQuestion("example.com.", TypeTXT)
+	r, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Fatal("failed to exchange example.com", err)
+	}
+	txt = r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello example" {
+		t.Error("unexpected result for example.com", txt, "!= Hello example")
+	}
+
+	// Test Mixes cased as noticed by Ask.
+	m.SetQuestion("eXaMplE.cOm.", TypeTXT)
+	r, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Error("failed to exchange eXaMplE.cOm", err)
+	}
+	txt = r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello example" {
+		t.Error("unexpected result for example.com", txt, "!= Hello example")
+	}
+}
+
+func TestServingTLS(t *testing.T) {
+	HandleFunc("miek.nl.", HelloServer)
+	HandleFunc("example.com.", AnotherHelloServer)
+	defer HandleRemove("miek.nl.")
+	defer HandleRemove("example.com.")
+
+	cert, err := tls.X509KeyPair(CertPEMBlock, KeyPEMBlock)
+	if err != nil {
+		t.Fatalf("unable to build certificate: %v", err)
+	}
+
+	config := tls.Config{
+		Certificates: []tls.Certificate{cert},
+	}
+
+	s, addrstr, err := RunLocalTLSServer("127.0.0.1:0", &config)
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	c := new(Client)
+	c.Net = "tcp-tls"
+	c.TLSConfig = &tls.Config{
+		InsecureSkipVerify: true,
+	}
+
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeTXT)
+	r, _, err := c.Exchange(m, addrstr)
+	if err != nil || len(r.Extra) == 0 {
+		t.Fatal("failed to exchange miek.nl", err)
+	}
+	txt := r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello world" {
+		t.Error("unexpected result for miek.nl", txt, "!= Hello world")
+	}
+
+	m.SetQuestion("example.com.", TypeTXT)
+	r, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Fatal("failed to exchange example.com", err)
+	}
+	txt = r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello example" {
+		t.Error("unexpected result for example.com", txt, "!= Hello example")
+	}
+
+	// Test Mixes cased as noticed by Ask.
+	m.SetQuestion("eXaMplE.cOm.", TypeTXT)
+	r, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Error("failed to exchange eXaMplE.cOm", err)
+	}
+	txt = r.Extra[0].(*TXT).Txt[0]
+	if txt != "Hello example" {
+		t.Error("unexpected result for example.com", txt, "!= Hello example")
+	}
+}
+
+func BenchmarkServe(b *testing.B) {
+	b.StopTimer()
+	HandleFunc("miek.nl.", HelloServer)
+	defer HandleRemove("miek.nl.")
+	a := runtime.GOMAXPROCS(4)
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		b.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	c := new(Client)
+	m := new(Msg)
+	m.SetQuestion("miek.nl", TypeSOA)
+
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		c.Exchange(m, addrstr)
+	}
+	runtime.GOMAXPROCS(a)
+}
+
+func benchmarkServe6(b *testing.B) {
+	b.StopTimer()
+	HandleFunc("miek.nl.", HelloServer)
+	defer HandleRemove("miek.nl.")
+	a := runtime.GOMAXPROCS(4)
+	s, addrstr, err := RunLocalUDPServer("[::1]:0")
+	if err != nil {
+		b.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	c := new(Client)
+	m := new(Msg)
+	m.SetQuestion("miek.nl", TypeSOA)
+
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		c.Exchange(m, addrstr)
+	}
+	runtime.GOMAXPROCS(a)
+}
+
+func HelloServerCompress(w ResponseWriter, req *Msg) {
+	m := new(Msg)
+	m.SetReply(req)
+	m.Extra = make([]RR, 1)
+	m.Extra[0] = &TXT{Hdr: RR_Header{Name: m.Question[0].Name, Rrtype: TypeTXT, Class: ClassINET, Ttl: 0}, Txt: []string{"Hello world"}}
+	m.Compress = true
+	w.WriteMsg(m)
+}
+
+func BenchmarkServeCompress(b *testing.B) {
+	b.StopTimer()
+	HandleFunc("miek.nl.", HelloServerCompress)
+	defer HandleRemove("miek.nl.")
+	a := runtime.GOMAXPROCS(4)
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		b.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	c := new(Client)
+	m := new(Msg)
+	m.SetQuestion("miek.nl", TypeSOA)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		c.Exchange(m, addrstr)
+	}
+	runtime.GOMAXPROCS(a)
+}
+
+func TestDotAsCatchAllWildcard(t *testing.T) {
+	mux := NewServeMux()
+	mux.Handle(".", HandlerFunc(HelloServer))
+	mux.Handle("example.com.", HandlerFunc(AnotherHelloServer))
+
+	handler := mux.match("www.miek.nl.", TypeTXT)
+	if handler == nil {
+		t.Error("wildcard match failed")
+	}
+
+	handler = mux.match("www.example.com.", TypeTXT)
+	if handler == nil {
+		t.Error("example.com match failed")
+	}
+
+	handler = mux.match("a.www.example.com.", TypeTXT)
+	if handler == nil {
+		t.Error("a.www.example.com match failed")
+	}
+
+	handler = mux.match("boe.", TypeTXT)
+	if handler == nil {
+		t.Error("boe. match failed")
+	}
+}
+
+func TestCaseFolding(t *testing.T) {
+	mux := NewServeMux()
+	mux.Handle("_udp.example.com.", HandlerFunc(HelloServer))
+
+	handler := mux.match("_dns._udp.example.com.", TypeSRV)
+	if handler == nil {
+		t.Error("case sensitive characters folded")
+	}
+
+	handler = mux.match("_DNS._UDP.EXAMPLE.COM.", TypeSRV)
+	if handler == nil {
+		t.Error("case insensitive characters not folded")
+	}
+}
+
+func TestRootServer(t *testing.T) {
+	mux := NewServeMux()
+	mux.Handle(".", HandlerFunc(HelloServer))
+
+	handler := mux.match(".", TypeNS)
+	if handler == nil {
+		t.Error("root match failed")
+	}
+}
+
+type maxRec struct {
+	max int
+	sync.RWMutex
+}
+
+var M = new(maxRec)
+
+func HelloServerLargeResponse(resp ResponseWriter, req *Msg) {
+	m := new(Msg)
+	m.SetReply(req)
+	m.Authoritative = true
+	m1 := 0
+	M.RLock()
+	m1 = M.max
+	M.RUnlock()
+	for i := 0; i < m1; i++ {
+		aRec := &A{
+			Hdr: RR_Header{
+				Name:   req.Question[0].Name,
+				Rrtype: TypeA,
+				Class:  ClassINET,
+				Ttl:    0,
+			},
+			A: net.ParseIP(fmt.Sprintf("127.0.0.%d", i+1)).To4(),
+		}
+		m.Answer = append(m.Answer, aRec)
+	}
+	resp.WriteMsg(m)
+}
+
+func TestServingLargeResponses(t *testing.T) {
+	HandleFunc("example.", HelloServerLargeResponse)
+	defer HandleRemove("example.")
+
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	// Create request
+	m := new(Msg)
+	m.SetQuestion("web.service.example.", TypeANY)
+
+	c := new(Client)
+	c.Net = "udp"
+	M.Lock()
+	M.max = 2
+	M.Unlock()
+	_, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+	// This must fail
+	M.Lock()
+	M.max = 20
+	M.Unlock()
+	_, _, err = c.Exchange(m, addrstr)
+	if err == nil {
+		t.Error("failed to fail exchange, this should generate packet error")
+	}
+	// But this must work again
+	c.UDPSize = 7000
+	_, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Errorf("failed to exchange: %v", err)
+	}
+}
+
+func TestServingResponse(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+	HandleFunc("miek.nl.", HelloServer)
+	s, addrstr, err := RunLocalUDPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+
+	c := new(Client)
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeTXT)
+	m.Response = false
+	_, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Fatal("failed to exchange", err)
+	}
+	m.Response = true
+	_, _, err = c.Exchange(m, addrstr)
+	if err == nil {
+		t.Fatal("exchanged response message")
+	}
+
+	s.Shutdown()
+	s, addrstr, err = RunLocalUDPServerUnsafe("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	defer s.Shutdown()
+
+	m.Response = true
+	_, _, err = c.Exchange(m, addrstr)
+	if err != nil {
+		t.Fatal("could exchanged response message in Unsafe mode")
+	}
+}
+
+func TestShutdownTCP(t *testing.T) {
+	s, _, err := RunLocalTCPServer("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	err = s.Shutdown()
+	if err != nil {
+		t.Errorf("could not shutdown test TCP server, %v", err)
+	}
+}
+
+func TestShutdownTLS(t *testing.T) {
+	cert, err := tls.X509KeyPair(CertPEMBlock, KeyPEMBlock)
+	if err != nil {
+		t.Fatalf("unable to build certificate: %v", err)
+	}
+
+	config := tls.Config{
+		Certificates: []tls.Certificate{cert},
+	}
+
+	s, _, err := RunLocalTLSServer("127.0.0.1:0", &config)
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	err = s.Shutdown()
+	if err != nil {
+		t.Errorf("could not shutdown test TLS server, %v", err)
+	}
+}
+
+type trigger struct {
+	done bool
+	sync.RWMutex
+}
+
+func (t *trigger) Set() {
+	t.Lock()
+	defer t.Unlock()
+	t.done = true
+}
+func (t *trigger) Get() bool {
+	t.RLock()
+	defer t.RUnlock()
+	return t.done
+}
+
+func TestHandlerCloseTCP(t *testing.T) {
+
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		panic(err)
+	}
+	addr := ln.Addr().String()
+
+	server := &Server{Addr: addr, Net: "tcp", Listener: ln}
+
+	hname := "testhandlerclosetcp."
+	triggered := &trigger{}
+	HandleFunc(hname, func(w ResponseWriter, r *Msg) {
+		triggered.Set()
+		w.Close()
+	})
+	defer HandleRemove(hname)
+
+	go func() {
+		defer server.Shutdown()
+		c := &Client{Net: "tcp"}
+		m := new(Msg).SetQuestion(hname, 1)
+		tries := 0
+	exchange:
+		_, _, err := c.Exchange(m, addr)
+		if err != nil && err != io.EOF {
+			t.Logf("exchange failed: %s\n", err)
+			if tries == 3 {
+				return
+			}
+			time.Sleep(time.Second / 10)
+			tries += 1
+			goto exchange
+		}
+	}()
+	server.ActivateAndServe()
+	if !triggered.Get() {
+		t.Fatalf("handler never called")
+	}
+}
+
+func TestShutdownUDP(t *testing.T) {
+	s, _, fin, err := RunLocalUDPServerWithFinChan("127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("unable to run test server: %v", err)
+	}
+	err = s.Shutdown()
+	if err != nil {
+		t.Errorf("could not shutdown test UDP server, %v", err)
+	}
+	select {
+	case <-fin:
+	case <-time.After(2 * time.Second):
+		t.Error("Could not shutdown test UDP server. Gave up waiting")
+	}
+}
+
+type ExampleFrameLengthWriter struct {
+	Writer
+}
+
+func (e *ExampleFrameLengthWriter) Write(m []byte) (int, error) {
+	fmt.Println("writing raw DNS message of length", len(m))
+	return e.Writer.Write(m)
+}
+
+func ExampleDecorateWriter() {
+	// instrument raw DNS message writing
+	wf := DecorateWriter(func(w Writer) Writer {
+		return &ExampleFrameLengthWriter{w}
+	})
+
+	// simple UDP server
+	pc, err := net.ListenPacket("udp", "127.0.0.1:0")
+	if err != nil {
+		fmt.Println(err.Error())
+		return
+	}
+	server := &Server{
+		PacketConn:     pc,
+		DecorateWriter: wf,
+		ReadTimeout:    time.Hour, WriteTimeout: time.Hour,
+	}
+
+	waitLock := sync.Mutex{}
+	waitLock.Lock()
+	server.NotifyStartedFunc = waitLock.Unlock
+	defer server.Shutdown()
+
+	go func() {
+		server.ActivateAndServe()
+		pc.Close()
+	}()
+
+	waitLock.Lock()
+
+	HandleFunc("miek.nl.", HelloServer)
+
+	c := new(Client)
+	m := new(Msg)
+	m.SetQuestion("miek.nl.", TypeTXT)
+	_, _, err = c.Exchange(m, pc.LocalAddr().String())
+	if err != nil {
+		fmt.Println("failed to exchange", err.Error())
+		return
+	}
+	// Output: writing raw DNS message of length 56
+}
+
+var (
+	// CertPEMBlock is a X509 data used to test TLS servers (used with tls.X509KeyPair)
+	CertPEMBlock = []byte(`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`)
+
+	// KeyPEMBlock is a X509 data used to test TLS servers (used with tls.X509KeyPair)
+	KeyPEMBlock = []byte(`-----BEGIN RSA PRIVATE KEY-----
+MIIEpQIBAAKCAQEA146jurJLz9N5OfAjY0IIHfRv5rflmvsUVPll4iggh7bWsDPM
+frJaucn7BwsMZcLBp+/R5iannDaoB29hlgVwL1VaJBQ03AtYVD+PoKdoLvTctu1B
+045S5jtJf8WeTDfLXysmJRcNfLV7t35Gj8h4/L/w9UQ5LqOAEXRbxknvE6orG4S5
+NvvaMMXyBmxDPRXYsPKgcgtvnfhX78yCs9xn0FcJ9FaEaJvC+jQSADatSBqweSXn
+2Qep7w537sZAZmOxdeddxyrhCfCrC1lmVlfTj1OI+COEbfliTZSo2w9rKx8cq0tk
+Q7K/dfJwpDaFlTTt7GatF5FinnHXPdtby+IIpwIDAQABAoIBAAJK4RDmPooqTJrC
+JA41MJLo+5uvjwCT9QZmVKAQHzByUFw1YNJkITTiognUI0CdzqNzmH7jIFs39ZeG
+proKusO2G6xQjrNcZ4cV2fgyb5g4QHStl0qhs94A+WojduiGm2IaumAgm6Mc5wDv
+ld6HmknN3Mku/ZCyanVFEIjOVn2WB7ZQLTBs6ZYaebTJG2Xv6p9t2YJW7pPQ9Xce
+s9ohAWohyM4X/OvfnfnLtQp2YLw/BxwehBsCR5SXM3ibTKpFNtxJC8hIfTuWtxZu
+2ywrmXShYBRB1WgtZt5k04bY/HFncvvcHK3YfI1+w4URKtwdaQgPUQRbVwDwuyBn
+flfkCJECgYEA/eWt01iEyE/lXkGn6V9lCocUU7lCU6yk5UT8VXVUc5If4KZKPfCk
+p4zJDOqwn2eM673aWz/mG9mtvAvmnugaGjcaVCyXOp/D/GDmKSoYcvW5B/yjfkLy
+dK6Yaa5LDRVYlYgyzcdCT5/9Qc626NzFwKCZNI4ncIU8g7ViATRxWJ8CgYEA2Ver
+vZ0M606sfgC0H3NtwNBxmuJ+lIF5LNp/wDi07lDfxRR1rnZMX5dnxjcpDr/zvm8J
+WtJJX3xMgqjtHuWKL3yKKony9J5ZPjichSbSbhrzfovgYIRZLxLLDy4MP9L3+CX/
+yBXnqMWuSnFX+M5fVGxdDWiYF3V+wmeOv9JvavkCgYEAiXAPDFzaY+R78O3xiu7M
+r0o3wqqCMPE/wav6O/hrYrQy9VSO08C0IM6g9pEEUwWmzuXSkZqhYWoQFb8Lc/GI
+T7CMXAxXQLDDUpbRgG79FR3Wr3AewHZU8LyiXHKwxcBMV4WGmsXGK3wbh8fyU1NO
+6NsGk+BvkQVOoK1LBAPzZ1kCgYEAsBSmD8U33T9s4dxiEYTrqyV0lH3g/SFz8ZHH
+pAyNEPI2iC1ONhyjPWKlcWHpAokiyOqeUpVBWnmSZtzC1qAydsxYB6ShT+sl9BHb
+RMix/QAauzBJhQhUVJ3OIys0Q1UBDmqCsjCE8SfOT4NKOUnA093C+YT+iyrmmktZ
+zDCJkckCgYEAndqM5KXGk5xYo+MAA1paZcbTUXwaWwjLU+XSRSSoyBEi5xMtfvUb
+7+a1OMhLwWbuz+pl64wFKrbSUyimMOYQpjVE/1vk/kb99pxbgol27hdKyTH1d+ov
+kFsxKCqxAnBVGEWAvVZAiiTOxleQFjz5RnL0BQp9Lg2cQe+dvuUmIAA=
+-----END RSA PRIVATE KEY-----`)
+)

sig0.go

@@ -0,0 +1,216 @@
+package dns
+
+import (
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"math/big"
+	"strings"
+	"time"
+)
+
+// Sign signs a dns.Msg. It fills the signature with the appropriate data.
+// The SIG record should have the SignerName, KeyTag, Algorithm, Inception
+// and Expiration set.
+func (rr *SIG) Sign(k crypto.Signer, m *Msg) ([]byte, error) {
+	if k == nil {
+		return nil, ErrPrivKey
+	}
+	if rr.KeyTag == 0 || len(rr.SignerName) == 0 || rr.Algorithm == 0 {
+		return nil, ErrKey
+	}
+	rr.Header().Rrtype = TypeSIG
+	rr.Header().Class = ClassANY
+	rr.Header().Ttl = 0
+	rr.Header().Name = "."
+	rr.OrigTtl = 0
+	rr.TypeCovered = 0
+	rr.Labels = 0
+
+	buf := make([]byte, m.Len()+rr.len())
+	mbuf, err := m.PackBuffer(buf)
+	if err != nil {
+		return nil, err
+	}
+	if &buf[0] != &mbuf[0] {
+		return nil, ErrBuf
+	}
+	off, err := PackRR(rr, buf, len(mbuf), nil, false)
+	if err != nil {
+		return nil, err
+	}
+	buf = buf[:off:cap(buf)]
+
+	hash, ok := AlgorithmToHash[rr.Algorithm]
+	if !ok {
+		return nil, ErrAlg
+	}
+
+	hasher := hash.New()
+	// Write SIG rdata
+	hasher.Write(buf[len(mbuf)+1+2+2+4+2:])
+	// Write message
+	hasher.Write(buf[:len(mbuf)])
+
+	signature, err := sign(k, hasher.Sum(nil), hash, rr.Algorithm)
+	if err != nil {
+		return nil, err
+	}
+
+	rr.Signature = toBase64(signature)
+	sig := string(signature)
+
+	buf = append(buf, sig...)
+	if len(buf) > int(^uint16(0)) {
+		return nil, ErrBuf
+	}
+	// Adjust sig data length
+	rdoff := len(mbuf) + 1 + 2 + 2 + 4
+	rdlen, _ := unpackUint16(buf, rdoff)
+	rdlen += uint16(len(sig))
+	buf[rdoff], buf[rdoff+1] = packUint16(rdlen)
+	// Adjust additional count
+	adc, _ := unpackUint16(buf, 10)
+	adc++
+	buf[10], buf[11] = packUint16(adc)
+	return buf, nil
+}
+
+// Verify validates the message buf using the key k.
+// It's assumed that buf is a valid message from which rr was unpacked.
+func (rr *SIG) Verify(k *KEY, buf []byte) error {
+	if k == nil {
+		return ErrKey
+	}
+	if rr.KeyTag == 0 || len(rr.SignerName) == 0 || rr.Algorithm == 0 {
+		return ErrKey
+	}
+
+	var hash crypto.Hash
+	switch rr.Algorithm {
+	case DSA, RSASHA1:
+		hash = crypto.SHA1
+	case RSASHA256, ECDSAP256SHA256:
+		hash = crypto.SHA256
+	case ECDSAP384SHA384:
+		hash = crypto.SHA384
+	case RSASHA512:
+		hash = crypto.SHA512
+	default:
+		return ErrAlg
+	}
+	hasher := hash.New()
+
+	buflen := len(buf)
+	qdc, _ := unpackUint16(buf, 4)
+	anc, _ := unpackUint16(buf, 6)
+	auc, _ := unpackUint16(buf, 8)
+	adc, offset := unpackUint16(buf, 10)
+	var err error
+	for i := uint16(0); i < qdc && offset < buflen; i++ {
+		_, offset, err = UnpackDomainName(buf, offset)
+		if err != nil {
+			return err
+		}
+		// Skip past Type and Class
+		offset += 2 + 2
+	}
+	for i := uint16(1); i < anc+auc+adc && offset < buflen; i++ {
+		_, offset, err = UnpackDomainName(buf, offset)
+		if err != nil {
+			return err
+		}
+		// Skip past Type, Class and TTL
+		offset += 2 + 2 + 4
+		if offset+1 >= buflen {
+			continue
+		}
+		var rdlen uint16
+		rdlen, offset = unpackUint16(buf, offset)
+		offset += int(rdlen)
+	}
+	if offset >= buflen {
+		return &Error{err: "overflowing unpacking signed message"}
+	}
+
+	// offset should be just prior to SIG
+	bodyend := offset
+	// owner name SHOULD be root
+	_, offset, err = UnpackDomainName(buf, offset)
+	if err != nil {
+		return err
+	}
+	// Skip Type, Class, TTL, RDLen
+	offset += 2 + 2 + 4 + 2
+	sigstart := offset
+	// Skip Type Covered, Algorithm, Labels, Original TTL
+	offset += 2 + 1 + 1 + 4
+	if offset+4+4 >= buflen {
+		return &Error{err: "overflow unpacking signed message"}
+	}
+	expire := uint32(buf[offset])<<24 | uint32(buf[offset+1])<<16 | uint32(buf[offset+2])<<8 | uint32(buf[offset+3])
+	offset += 4
+	incept := uint32(buf[offset])<<24 | uint32(buf[offset+1])<<16 | uint32(buf[offset+2])<<8 | uint32(buf[offset+3])
+	offset += 4
+	now := uint32(time.Now().Unix())
+	if now < incept || now > expire {
+		return ErrTime
+	}
+	// Skip key tag
+	offset += 2
+	var signername string
+	signername, offset, err = UnpackDomainName(buf, offset)
+	if err != nil {
+		return err
+	}
+	// If key has come from the DNS name compression might
+	// have mangled the case of the name
+	if strings.ToLower(signername) != strings.ToLower(k.Header().Name) {
+		return &Error{err: "signer name doesn't match key name"}
+	}
+	sigend := offset
+	hasher.Write(buf[sigstart:sigend])
+	hasher.Write(buf[:10])
+	hasher.Write([]byte{
+		byte((adc - 1) << 8),
+		byte(adc - 1),
+	})
+	hasher.Write(buf[12:bodyend])
+
+	hashed := hasher.Sum(nil)
+	sig := buf[sigend:]
+	switch k.Algorithm {
+	case DSA:
+		pk := k.publicKeyDSA()
+		sig = sig[1:]
+		r := big.NewInt(0)
+		r.SetBytes(sig[:len(sig)/2])
+		s := big.NewInt(0)
+		s.SetBytes(sig[len(sig)/2:])
+		if pk != nil {
+			if dsa.Verify(pk, hashed, r, s) {
+				return nil
+			}
+			return ErrSig
+		}
+	case RSASHA1, RSASHA256, RSASHA512:
+		pk := k.publicKeyRSA()
+		if pk != nil {
+			return rsa.VerifyPKCS1v15(pk, hash, hashed, sig)
+		}
+	case ECDSAP256SHA256, ECDSAP384SHA384:
+		pk := k.publicKeyECDSA()
+		r := big.NewInt(0)
+		r.SetBytes(sig[:len(sig)/2])
+		s := big.NewInt(0)
+		s.SetBytes(sig[len(sig)/2:])
+		if pk != nil {
+			if ecdsa.Verify(pk, hashed, r, s) {
+				return nil
+			}
+			return ErrSig
+		}
+	}
+	return ErrKeyAlg
+}

sig0_test.go

@@ -0,0 +1,89 @@
+package dns
+
+import (
+	"crypto"
+	"testing"
+	"time"
+)
+
+func TestSIG0(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+	m := new(Msg)
+	m.SetQuestion("example.org.", TypeSOA)
+	for _, alg := range []uint8{ECDSAP256SHA256, ECDSAP384SHA384, RSASHA1, RSASHA256, RSASHA512} {
+		algstr := AlgorithmToString[alg]
+		keyrr := new(KEY)
+		keyrr.Hdr.Name = algstr + "."
+		keyrr.Hdr.Rrtype = TypeKEY
+		keyrr.Hdr.Class = ClassINET
+		keyrr.Algorithm = alg
+		keysize := 1024
+		switch alg {
+		case ECDSAP256SHA256:
+			keysize = 256
+		case ECDSAP384SHA384:
+			keysize = 384
+		}
+		pk, err := keyrr.Generate(keysize)
+		if err != nil {
+			t.Errorf("failed to generate key for “%s”: %v", algstr, err)
+			continue
+		}
+		now := uint32(time.Now().Unix())
+		sigrr := new(SIG)
+		sigrr.Hdr.Name = "."
+		sigrr.Hdr.Rrtype = TypeSIG
+		sigrr.Hdr.Class = ClassANY
+		sigrr.Algorithm = alg
+		sigrr.Expiration = now + 300
+		sigrr.Inception = now - 300
+		sigrr.KeyTag = keyrr.KeyTag()
+		sigrr.SignerName = keyrr.Hdr.Name
+		mb, err := sigrr.Sign(pk.(crypto.Signer), m)
+		if err != nil {
+			t.Errorf("failed to sign message using “%s”: %v", algstr, err)
+			continue
+		}
+		m := new(Msg)
+		if err := m.Unpack(mb); err != nil {
+			t.Errorf("failed to unpack message signed using “%s”: %v", algstr, err)
+			continue
+		}
+		if len(m.Extra) != 1 {
+			t.Errorf("missing SIG for message signed using “%s”", algstr)
+			continue
+		}
+		var sigrrwire *SIG
+		switch rr := m.Extra[0].(type) {
+		case *SIG:
+			sigrrwire = rr
+		default:
+			t.Errorf("expected SIG RR, instead: %v", rr)
+			continue
+		}
+		for _, rr := range []*SIG{sigrr, sigrrwire} {
+			id := "sigrr"
+			if rr == sigrrwire {
+				id = "sigrrwire"
+			}
+			if err := rr.Verify(keyrr, mb); err != nil {
+				t.Errorf("failed to verify “%s” signed SIG(%s): %v", algstr, id, err)
+				continue
+			}
+		}
+		mb[13]++
+		if err := sigrr.Verify(keyrr, mb); err == nil {
+			t.Errorf("verify succeeded on an altered message using “%s”", algstr)
+			continue
+		}
+		sigrr.Expiration = 2
+		sigrr.Inception = 1
+		mb, _ = sigrr.Sign(pk.(crypto.Signer), m)
+		if err := sigrr.Verify(keyrr, mb); err == nil {
+			t.Errorf("verify succeeded on an expired message using “%s”", algstr)
+			continue
+		}
+	}
+}

singleinflight.go

@@ -0,0 +1,57 @@
+// Copyright 2013 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Adapted for dns package usage by Miek Gieben.
+
+package dns
+
+import "sync"
+import "time"
+
+// call is an in-flight or completed singleflight.Do call
+type call struct {
+	wg   sync.WaitGroup
+	val  *Msg
+	rtt  time.Duration
+	err  error
+	dups int
+}
+
+// singleflight represents a class of work and forms a namespace in
+// which units of work can be executed with duplicate suppression.
+type singleflight struct {
+	sync.Mutex                  // protects m
+	m          map[string]*call // lazily initialized
+}
+
+// Do executes and returns the results of the given function, making
+// sure that only one execution is in-flight for a given key at a
+// time. If a duplicate comes in, the duplicate caller waits for the
+// original to complete and receives the same results.
+// The return value shared indicates whether v was given to multiple callers.
+func (g *singleflight) Do(key string, fn func() (*Msg, time.Duration, error)) (v *Msg, rtt time.Duration, err error, shared bool) {
+	g.Lock()
+	if g.m == nil {
+		g.m = make(map[string]*call)
+	}
+	if c, ok := g.m[key]; ok {
+		c.dups++
+		g.Unlock()
+		c.wg.Wait()
+		return c.val, c.rtt, c.err, true
+	}
+	c := new(call)
+	c.wg.Add(1)
+	g.m[key] = c
+	g.Unlock()
+
+	c.val, c.rtt, c.err = fn()
+	c.wg.Done()
+
+	g.Lock()
+	delete(g.m, key)
+	g.Unlock()
+
+	return c.val, c.rtt, c.err, c.dups > 0
+}

tlsa.go

@@ -0,0 +1,86 @@
+package dns
+
+import (
+	"crypto/sha256"
+	"crypto/sha512"
+	"crypto/x509"
+	"encoding/hex"
+	"errors"
+	"io"
+	"net"
+	"strconv"
+)
+
+// CertificateToDANE converts a certificate to a hex string as used in the TLSA record.
+func CertificateToDANE(selector, matchingType uint8, cert *x509.Certificate) (string, error) {
+	switch matchingType {
+	case 0:
+		switch selector {
+		case 0:
+			return hex.EncodeToString(cert.Raw), nil
+		case 1:
+			return hex.EncodeToString(cert.RawSubjectPublicKeyInfo), nil
+		}
+	case 1:
+		h := sha256.New()
+		switch selector {
+		case 0:
+			io.WriteString(h, string(cert.Raw))
+			return hex.EncodeToString(h.Sum(nil)), nil
+		case 1:
+			io.WriteString(h, string(cert.RawSubjectPublicKeyInfo))
+			return hex.EncodeToString(h.Sum(nil)), nil
+		}
+	case 2:
+		h := sha512.New()
+		switch selector {
+		case 0:
+			io.WriteString(h, string(cert.Raw))
+			return hex.EncodeToString(h.Sum(nil)), nil
+		case 1:
+			io.WriteString(h, string(cert.RawSubjectPublicKeyInfo))
+			return hex.EncodeToString(h.Sum(nil)), nil
+		}
+	}
+	return "", errors.New("dns: bad TLSA MatchingType or TLSA Selector")
+}
+
+// Sign creates a TLSA record from an SSL certificate.
+func (r *TLSA) Sign(usage, selector, matchingType int, cert *x509.Certificate) (err error) {
+	r.Hdr.Rrtype = TypeTLSA
+	r.Usage = uint8(usage)
+	r.Selector = uint8(selector)
+	r.MatchingType = uint8(matchingType)
+
+	r.Certificate, err = CertificateToDANE(r.Selector, r.MatchingType, cert)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// Verify verifies a TLSA record against an SSL certificate. If it is OK
+// a nil error is returned.
+func (r *TLSA) Verify(cert *x509.Certificate) error {
+	c, err := CertificateToDANE(r.Selector, r.MatchingType, cert)
+	if err != nil {
+		return err // Not also ErrSig?
+	}
+	if r.Certificate == c {
+		return nil
+	}
+	return ErrSig // ErrSig, really?
+}
+
+// TLSAName returns the ownername of a TLSA resource record as per the
+// rules specified in RFC 6698, Section 3.
+func TLSAName(name, service, network string) (string, error) {
+	if !IsFqdn(name) {
+		return "", ErrFqdn
+	}
+	p, e := net.LookupPort(network, service)
+	if e != nil {
+		return "", e
+	}
+	return "_" + strconv.Itoa(p) + "_" + network + "." + name, nil
+}

tsig.go

@@ -0,0 +1,320 @@
+package dns
+
+import (
+	"crypto/hmac"
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/hex"
+	"hash"
+	"io"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// HMAC hashing codes. These are transmitted as domain names.
+const (
+	HmacMD5    = "hmac-md5.sig-alg.reg.int."
+	HmacSHA1   = "hmac-sha1."
+	HmacSHA256 = "hmac-sha256."
+	HmacSHA512 = "hmac-sha512."
+)
+
+// TSIG is the RR the holds the transaction signature of a message.
+// See RFC 2845 and RFC 4635.
+type TSIG struct {
+	Hdr        RR_Header
+	Algorithm  string `dns:"domain-name"`
+	TimeSigned uint64 `dns:"uint48"`
+	Fudge      uint16
+	MACSize    uint16
+	MAC        string `dns:"size-hex"`
+	OrigId     uint16
+	Error      uint16
+	OtherLen   uint16
+	OtherData  string `dns:"size-hex"`
+}
+
+// TSIG has no official presentation format, but this will suffice.
+
+func (rr *TSIG) String() string {
+	s := "\n;; TSIG PSEUDOSECTION:\n"
+	s += rr.Hdr.String() +
+		" " + rr.Algorithm +
+		" " + tsigTimeToString(rr.TimeSigned) +
+		" " + strconv.Itoa(int(rr.Fudge)) +
+		" " + strconv.Itoa(int(rr.MACSize)) +
+		" " + strings.ToUpper(rr.MAC) +
+		" " + strconv.Itoa(int(rr.OrigId)) +
+		" " + strconv.Itoa(int(rr.Error)) + // BIND prints NOERROR
+		" " + strconv.Itoa(int(rr.OtherLen)) +
+		" " + rr.OtherData
+	return s
+}
+
+// The following values must be put in wireformat, so that the MAC can be calculated.
+// RFC 2845, section 3.4.2. TSIG Variables.
+type tsigWireFmt struct {
+	// From RR_Header
+	Name  string `dns:"domain-name"`
+	Class uint16
+	Ttl   uint32
+	// Rdata of the TSIG
+	Algorithm  string `dns:"domain-name"`
+	TimeSigned uint64 `dns:"uint48"`
+	Fudge      uint16
+	// MACSize, MAC and OrigId excluded
+	Error     uint16
+	OtherLen  uint16
+	OtherData string `dns:"size-hex"`
+}
+
+// If we have the MAC use this type to convert it to wiredata.
+// Section 3.4.3. Request MAC
+type macWireFmt struct {
+	MACSize uint16
+	MAC     string `dns:"size-hex"`
+}
+
+// 3.3. Time values used in TSIG calculations
+type timerWireFmt struct {
+	TimeSigned uint64 `dns:"uint48"`
+	Fudge      uint16
+}
+
+// TsigGenerate fills out the TSIG record attached to the message.
+// The message should contain
+// a "stub" TSIG RR with the algorithm, key name (owner name of the RR),
+// time fudge (defaults to 300 seconds) and the current time
+// The TSIG MAC is saved in that Tsig RR.
+// When TsigGenerate is called for the first time requestMAC is set to the empty string and
+// timersOnly is false.
+// If something goes wrong an error is returned, otherwise it is nil.
+func TsigGenerate(m *Msg, secret, requestMAC string, timersOnly bool) ([]byte, string, error) {
+	if m.IsTsig() == nil {
+		panic("dns: TSIG not last RR in additional")
+	}
+	// If we barf here, the caller is to blame
+	rawsecret, err := fromBase64([]byte(secret))
+	if err != nil {
+		return nil, "", err
+	}
+
+	rr := m.Extra[len(m.Extra)-1].(*TSIG)
+	m.Extra = m.Extra[0 : len(m.Extra)-1] // kill the TSIG from the msg
+	mbuf, err := m.Pack()
+	if err != nil {
+		return nil, "", err
+	}
+	buf := tsigBuffer(mbuf, rr, requestMAC, timersOnly)
+
+	t := new(TSIG)
+	var h hash.Hash
+	switch rr.Algorithm {
+	case HmacMD5:
+		h = hmac.New(md5.New, []byte(rawsecret))
+	case HmacSHA1:
+		h = hmac.New(sha1.New, []byte(rawsecret))
+	case HmacSHA256:
+		h = hmac.New(sha256.New, []byte(rawsecret))
+	case HmacSHA512:
+		h = hmac.New(sha512.New, []byte(rawsecret))
+	default:
+		return nil, "", ErrKeyAlg
+	}
+	io.WriteString(h, string(buf))
+	t.MAC = hex.EncodeToString(h.Sum(nil))
+	t.MACSize = uint16(len(t.MAC) / 2) // Size is half!
+
+	t.Hdr = RR_Header{Name: rr.Hdr.Name, Rrtype: TypeTSIG, Class: ClassANY, Ttl: 0}
+	t.Fudge = rr.Fudge
+	t.TimeSigned = rr.TimeSigned
+	t.Algorithm = rr.Algorithm
+	t.OrigId = m.Id
+
+	tbuf := make([]byte, t.len())
+	if off, err := PackRR(t, tbuf, 0, nil, false); err == nil {
+		tbuf = tbuf[:off] // reset to actual size used
+	} else {
+		return nil, "", err
+	}
+	mbuf = append(mbuf, tbuf...)
+	rawSetExtraLen(mbuf, uint16(len(m.Extra)+1))
+	return mbuf, t.MAC, nil
+}
+
+// TsigVerify verifies the TSIG on a message.
+// If the signature does not validate err contains the
+// error, otherwise it is nil.
+func TsigVerify(msg []byte, secret, requestMAC string, timersOnly bool) error {
+	rawsecret, err := fromBase64([]byte(secret))
+	if err != nil {
+		return err
+	}
+	// Strip the TSIG from the incoming msg
+	stripped, tsig, err := stripTsig(msg)
+	if err != nil {
+		return err
+	}
+
+	msgMAC, err := hex.DecodeString(tsig.MAC)
+	if err != nil {
+		return err
+	}
+
+	buf := tsigBuffer(stripped, tsig, requestMAC, timersOnly)
+
+	// Fudge factor works both ways. A message can arrive before it was signed because
+	// of clock skew.
+	now := uint64(time.Now().Unix())
+	ti := now - tsig.TimeSigned
+	if now < tsig.TimeSigned {
+		ti = tsig.TimeSigned - now
+	}
+	if uint64(tsig.Fudge) < ti {
+		return ErrTime
+	}
+
+	var h hash.Hash
+	switch tsig.Algorithm {
+	case HmacMD5:
+		h = hmac.New(md5.New, rawsecret)
+	case HmacSHA1:
+		h = hmac.New(sha1.New, rawsecret)
+	case HmacSHA256:
+		h = hmac.New(sha256.New, rawsecret)
+	case HmacSHA512:
+		h = hmac.New(sha512.New, rawsecret)
+	default:
+		return ErrKeyAlg
+	}
+	h.Write(buf)
+	if !hmac.Equal(h.Sum(nil), msgMAC) {
+		return ErrSig
+	}
+	return nil
+}
+
+// Create a wiredata buffer for the MAC calculation.
+func tsigBuffer(msgbuf []byte, rr *TSIG, requestMAC string, timersOnly bool) []byte {
+	var buf []byte
+	if rr.TimeSigned == 0 {
+		rr.TimeSigned = uint64(time.Now().Unix())
+	}
+	if rr.Fudge == 0 {
+		rr.Fudge = 300 // Standard (RFC) default.
+	}
+
+	if requestMAC != "" {
+		m := new(macWireFmt)
+		m.MACSize = uint16(len(requestMAC) / 2)
+		m.MAC = requestMAC
+		buf = make([]byte, len(requestMAC)) // long enough
+		n, _ := PackStruct(m, buf, 0)
+		buf = buf[:n]
+	}
+
+	tsigvar := make([]byte, DefaultMsgSize)
+	if timersOnly {
+		tsig := new(timerWireFmt)
+		tsig.TimeSigned = rr.TimeSigned
+		tsig.Fudge = rr.Fudge
+		n, _ := PackStruct(tsig, tsigvar, 0)
+		tsigvar = tsigvar[:n]
+	} else {
+		tsig := new(tsigWireFmt)
+		tsig.Name = strings.ToLower(rr.Hdr.Name)
+		tsig.Class = ClassANY
+		tsig.Ttl = rr.Hdr.Ttl
+		tsig.Algorithm = strings.ToLower(rr.Algorithm)
+		tsig.TimeSigned = rr.TimeSigned
+		tsig.Fudge = rr.Fudge
+		tsig.Error = rr.Error
+		tsig.OtherLen = rr.OtherLen
+		tsig.OtherData = rr.OtherData
+		n, _ := PackStruct(tsig, tsigvar, 0)
+		tsigvar = tsigvar[:n]
+	}
+
+	if requestMAC != "" {
+		x := append(buf, msgbuf...)
+		buf = append(x, tsigvar...)
+	} else {
+		buf = append(msgbuf, tsigvar...)
+	}
+	return buf
+}
+
+// Strip the TSIG from the raw message.
+func stripTsig(msg []byte) ([]byte, *TSIG, error) {
+	// Copied from msg.go's Unpack()
+	// Header.
+	var dh Header
+	var err error
+	dns := new(Msg)
+	rr := new(TSIG)
+	off := 0
+	tsigoff := 0
+	if off, err = UnpackStruct(&dh, msg, off); err != nil {
+		return nil, nil, err
+	}
+	if dh.Arcount == 0 {
+		return nil, nil, ErrNoSig
+	}
+	// Rcode, see msg.go Unpack()
+	if int(dh.Bits&0xF) == RcodeNotAuth {
+		return nil, nil, ErrAuth
+	}
+
+	// Arrays.
+	dns.Question = make([]Question, dh.Qdcount)
+	dns.Answer = make([]RR, dh.Ancount)
+	dns.Ns = make([]RR, dh.Nscount)
+	dns.Extra = make([]RR, dh.Arcount)
+
+	for i := 0; i < len(dns.Question); i++ {
+		off, err = UnpackStruct(&dns.Question[i], msg, off)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+	for i := 0; i < len(dns.Answer); i++ {
+		dns.Answer[i], off, err = UnpackRR(msg, off)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+	for i := 0; i < len(dns.Ns); i++ {
+		dns.Ns[i], off, err = UnpackRR(msg, off)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+	for i := 0; i < len(dns.Extra); i++ {
+		tsigoff = off
+		dns.Extra[i], off, err = UnpackRR(msg, off)
+		if err != nil {
+			return nil, nil, err
+		}
+		if dns.Extra[i].Header().Rrtype == TypeTSIG {
+			rr = dns.Extra[i].(*TSIG)
+			// Adjust Arcount.
+			arcount, _ := unpackUint16(msg, 10)
+			msg[10], msg[11] = packUint16(arcount - 1)
+			break
+		}
+	}
+	if rr == nil {
+		return nil, nil, ErrNoSig
+	}
+	return msg[:tsigoff], rr, nil
+}
+
+// Translate the TSIG time signed into a date. There is no
+// need for RFC1982 calculations as this date is 48 bits.
+func tsigTimeToString(t uint64) string {
+	ti := time.Unix(int64(t), 0).UTC()
+	return ti.Format("20060102150405")
+}

types_generate.go

@@ -0,0 +1,266 @@
+//+build ignore
+
+// types_generate.go is meant to run with go generate. It will use
+// go/{importer,types} to track down all the RR struct types. Then for each type
+// it will generate conversion tables (TypeToRR and TypeToString) and banal
+// methods (len, Header, copy) based on the struct tags. The generated source is
+// written to ztypes.go, and is meant to be checked into git.
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/format"
+	"go/importer"
+	"go/types"
+	"log"
+	"os"
+	"strings"
+	"text/template"
+)
+
+var skipLen = map[string]struct{}{
+	"NSEC":     {},
+	"NSEC3":    {},
+	"OPT":      {},
+	"WKS":      {},
+	"IPSECKEY": {},
+}
+
+var packageHdr = `
+// *** DO NOT MODIFY ***
+// AUTOGENERATED BY go generate
+
+package dns
+
+import (
+	"encoding/base64"
+	"net"
+)
+
+`
+
+var TypeToRR = template.Must(template.New("TypeToRR").Parse(`
+// TypeToRR is a map of constructors for each RR type.
+var TypeToRR = map[uint16]func() RR{
+{{range .}}{{if ne . "RFC3597"}}  Type{{.}}:  func() RR { return new({{.}}) },
+{{end}}{{end}}                    }
+
+`))
+
+var typeToString = template.Must(template.New("typeToString").Parse(`
+// TypeToString is a map of strings for each RR type.
+var TypeToString = map[uint16]string{
+{{range .}}{{if ne . "NSAPPTR"}}  Type{{.}}: "{{.}}",
+{{end}}{{end}}                    TypeNSAPPTR:    "NSAP-PTR",
+}
+
+`))
+
+var headerFunc = template.Must(template.New("headerFunc").Parse(`
+// Header() functions
+{{range .}}  func (rr *{{.}}) Header() *RR_Header { return &rr.Hdr }
+{{end}}
+
+`))
+
+// getTypeStruct will take a type and the package scope, and return the
+// (innermost) struct if the type is considered a RR type (currently defined as
+// those structs beginning with a RR_Header, could be redefined as implementing
+// the RR interface). The bool return value indicates if embedded structs were
+// resolved.
+func getTypeStruct(t types.Type, scope *types.Scope) (*types.Struct, bool) {
+	st, ok := t.Underlying().(*types.Struct)
+	if !ok {
+		return nil, false
+	}
+	if st.Field(0).Type() == scope.Lookup("RR_Header").Type() {
+		return st, false
+	}
+	if st.Field(0).Anonymous() {
+		st, _ := getTypeStruct(st.Field(0).Type(), scope)
+		return st, true
+	}
+	return nil, false
+}
+
+func main() {
+	// Import and type-check the package
+	pkg, err := importer.Default().Import("github.com/miekg/dns")
+	fatalIfErr(err)
+	scope := pkg.Scope()
+
+	// Collect constants like TypeX
+	var numberedTypes []string
+	for _, name := range scope.Names() {
+		o := scope.Lookup(name)
+		if o == nil || !o.Exported() {
+			continue
+		}
+		b, ok := o.Type().(*types.Basic)
+		if !ok || b.Kind() != types.Uint16 {
+			continue
+		}
+		if !strings.HasPrefix(o.Name(), "Type") {
+			continue
+		}
+		name := strings.TrimPrefix(o.Name(), "Type")
+		if name == "PrivateRR" {
+			continue
+		}
+		numberedTypes = append(numberedTypes, name)
+	}
+
+	// Collect actual types (*X)
+	var namedTypes []string
+	for _, name := range scope.Names() {
+		o := scope.Lookup(name)
+		if o == nil || !o.Exported() {
+			continue
+		}
+		if st, _ := getTypeStruct(o.Type(), scope); st == nil {
+			continue
+		}
+		if name == "PrivateRR" {
+			continue
+		}
+
+		// Check if corresponding TypeX exists
+		if scope.Lookup("Type"+o.Name()) == nil && o.Name() != "RFC3597" {
+			log.Fatalf("Constant Type%s does not exist.", o.Name())
+		}
+
+		namedTypes = append(namedTypes, o.Name())
+	}
+
+	b := &bytes.Buffer{}
+	b.WriteString(packageHdr)
+
+	// Generate TypeToRR
+	fatalIfErr(TypeToRR.Execute(b, namedTypes))
+
+	// Generate typeToString
+	fatalIfErr(typeToString.Execute(b, numberedTypes))
+
+	// Generate headerFunc
+	fatalIfErr(headerFunc.Execute(b, namedTypes))
+
+	// Generate len()
+	fmt.Fprint(b, "// len() functions\n")
+	for _, name := range namedTypes {
+		if _, ok := skipLen[name]; ok {
+			continue
+		}
+		o := scope.Lookup(name)
+		st, isEmbedded := getTypeStruct(o.Type(), scope)
+		if isEmbedded {
+			continue
+		}
+		fmt.Fprintf(b, "func (rr *%s) len() int {\n", name)
+		fmt.Fprintf(b, "l := rr.Hdr.len()\n")
+		for i := 1; i < st.NumFields(); i++ {
+			o := func(s string) { fmt.Fprintf(b, s, st.Field(i).Name()) }
+
+			if _, ok := st.Field(i).Type().(*types.Slice); ok {
+				switch st.Tag(i) {
+				case `dns:"-"`:
+					// ignored
+				case `dns:"cdomain-name"`, `dns:"domain-name"`, `dns:"txt"`:
+					o("for _, x := range rr.%s { l += len(x) + 1 }\n")
+				default:
+					log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
+				}
+				continue
+			}
+
+			switch st.Tag(i) {
+			case `dns:"-"`:
+				// ignored
+			case `dns:"cdomain-name"`, `dns:"domain-name"`:
+				o("l += len(rr.%s) + 1\n")
+			case `dns:"octet"`:
+				o("l += len(rr.%s)\n")
+			case `dns:"base64"`:
+				o("l += base64.StdEncoding.DecodedLen(len(rr.%s))\n")
+			case `dns:"size-hex"`, `dns:"hex"`:
+				o("l += len(rr.%s)/2 + 1\n")
+			case `dns:"a"`:
+				o("l += net.IPv4len // %s\n")
+			case `dns:"aaaa"`:
+				o("l += net.IPv6len // %s\n")
+			case `dns:"txt"`:
+				o("for _, t := range rr.%s { l += len(t) + 1 }\n")
+			case `dns:"uint48"`:
+				o("l += 6 // %s\n")
+			case "":
+				switch st.Field(i).Type().(*types.Basic).Kind() {
+				case types.Uint8:
+					o("l += 1 // %s\n")
+				case types.Uint16:
+					o("l += 2 // %s\n")
+				case types.Uint32:
+					o("l += 4 // %s\n")
+				case types.Uint64:
+					o("l += 8 // %s\n")
+				case types.String:
+					o("l += len(rr.%s) + 1\n")
+				default:
+					log.Fatalln(name, st.Field(i).Name())
+				}
+			default:
+				log.Fatalln(name, st.Field(i).Name(), st.Tag(i))
+			}
+		}
+		fmt.Fprintf(b, "return l }\n")
+	}
+
+	// Generate copy()
+	fmt.Fprint(b, "// copy() functions\n")
+	for _, name := range namedTypes {
+		o := scope.Lookup(name)
+		st, isEmbedded := getTypeStruct(o.Type(), scope)
+		if isEmbedded {
+			continue
+		}
+		fmt.Fprintf(b, "func (rr *%s) copy() RR {\n", name)
+		fields := []string{"*rr.Hdr.copyHeader()"}
+		for i := 1; i < st.NumFields(); i++ {
+			f := st.Field(i).Name()
+			if sl, ok := st.Field(i).Type().(*types.Slice); ok {
+				t := sl.Underlying().String()
+				t = strings.TrimPrefix(t, "[]")
+				t = strings.TrimPrefix(t, "github.com/miekg/dns.")
+				fmt.Fprintf(b, "%s := make([]%s, len(rr.%s)); copy(%s, rr.%s)\n",
+					f, t, f, f, f)
+				fields = append(fields, f)
+				continue
+			}
+			if st.Field(i).Type().String() == "net.IP" {
+				fields = append(fields, "copyIP(rr."+f+")")
+				continue
+			}
+			fields = append(fields, "rr."+f)
+		}
+		fmt.Fprintf(b, "return &%s{%s}\n", name, strings.Join(fields, ","))
+		fmt.Fprintf(b, "}\n")
+	}
+
+	// gofmt
+	res, err := format.Source(b.Bytes())
+	if err != nil {
+		b.WriteTo(os.Stderr)
+		log.Fatal(err)
+	}
+
+	// write result
+	f, err := os.Create("ztypes.go")
+	fatalIfErr(err)
+	defer f.Close()
+	f.Write(res)
+}
+
+func fatalIfErr(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+}

types_test.go

@@ -0,0 +1,42 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestCmToM(t *testing.T) {
+	s := cmToM(0, 0)
+	if s != "0.00" {
+		t.Error("0, 0")
+	}
+
+	s = cmToM(1, 0)
+	if s != "0.01" {
+		t.Error("1, 0")
+	}
+
+	s = cmToM(3, 1)
+	if s != "0.30" {
+		t.Error("3, 1")
+	}
+
+	s = cmToM(4, 2)
+	if s != "4" {
+		t.Error("4, 2")
+	}
+
+	s = cmToM(5, 3)
+	if s != "50" {
+		t.Error("5, 3")
+	}
+
+	s = cmToM(7, 5)
+	if s != "7000" {
+		t.Error("7, 5")
+	}
+
+	s = cmToM(9, 9)
+	if s != "90000000" {
+		t.Error("9, 9")
+	}
+}

udp.go

@@ -0,0 +1,58 @@
+// +build !windows
+
+package dns
+
+import (
+	"net"
+	"syscall"
+)
+
+// SessionUDP holds the remote address and the associated
+// out-of-band data.
+type SessionUDP struct {
+	raddr   *net.UDPAddr
+	context []byte
+}
+
+// RemoteAddr returns the remote network address.
+func (s *SessionUDP) RemoteAddr() net.Addr { return s.raddr }
+
+// setUDPSocketOptions sets the UDP socket options.
+// This function is implemented on a per platform basis. See udp_*.go for more details
+func setUDPSocketOptions(conn *net.UDPConn) error {
+	sa, err := getUDPSocketName(conn)
+	if err != nil {
+		return err
+	}
+	switch sa.(type) {
+	case *syscall.SockaddrInet6:
+		v6only, err := getUDPSocketOptions6Only(conn)
+		if err != nil {
+			return err
+		}
+		setUDPSocketOptions6(conn)
+		if !v6only {
+			setUDPSocketOptions4(conn)
+		}
+	case *syscall.SockaddrInet4:
+		setUDPSocketOptions4(conn)
+	}
+	return nil
+}
+
+// ReadFromSessionUDP acts just like net.UDPConn.ReadFrom(), but returns a session object instead of a
+// net.UDPAddr.
+func ReadFromSessionUDP(conn *net.UDPConn, b []byte) (int, *SessionUDP, error) {
+	oob := make([]byte, 40)
+	n, oobn, _, raddr, err := conn.ReadMsgUDP(b, oob)
+	if err != nil {
+		return n, nil, err
+	}
+	return n, &SessionUDP{raddr, oob[:oobn]}, err
+}
+
+// WriteToSessionUDP acts just like net.UDPConn.WritetTo(), but uses a *SessionUDP instead of a net.Addr.
+func WriteToSessionUDP(conn *net.UDPConn, b []byte, session *SessionUDP) (int, error) {
+	n, _, err := conn.WriteMsgUDP(b, session.context, session.raddr)
+	return n, err
+}

udp_linux.go

@@ -0,0 +1,73 @@
+// +build linux
+
+package dns
+
+// See:
+// * http://stackoverflow.com/questions/3062205/setting-the-source-ip-for-a-udp-socket and
+// * http://blog.powerdns.com/2012/10/08/on-binding-datagram-udp-sockets-to-the-any-addresses/
+//
+// Why do we need this: When listening on 0.0.0.0 with UDP so kernel decides what is the outgoing
+// interface, this might not always be the correct one. This code will make sure the egress
+// packet's interface matched the ingress' one.
+
+import (
+	"net"
+	"syscall"
+)
+
+// setUDPSocketOptions4 prepares the v4 socket for sessions.
+func setUDPSocketOptions4(conn *net.UDPConn) error {
+	file, err := conn.File()
+	if err != nil {
+		return err
+	}
+	if err := syscall.SetsockoptInt(int(file.Fd()), syscall.IPPROTO_IP, syscall.IP_PKTINFO, 1); err != nil {
+		return err
+	}
+	// Calling File() above results in the connection becoming blocking, we must fix that.
+	// See https://github.com/miekg/dns/issues/279
+	err = syscall.SetNonblock(int(file.Fd()), true)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// setUDPSocketOptions6 prepares the v6 socket for sessions.
+func setUDPSocketOptions6(conn *net.UDPConn) error {
+	file, err := conn.File()
+	if err != nil {
+		return err
+	}
+	if err := syscall.SetsockoptInt(int(file.Fd()), syscall.IPPROTO_IPV6, syscall.IPV6_RECVPKTINFO, 1); err != nil {
+		return err
+	}
+	err = syscall.SetNonblock(int(file.Fd()), true)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// getUDPSocketOption6Only return true if the socket is v6 only and false when it is v4/v6 combined
+// (dualstack).
+func getUDPSocketOptions6Only(conn *net.UDPConn) (bool, error) {
+	file, err := conn.File()
+	if err != nil {
+		return false, err
+	}
+	// dual stack. See http://stackoverflow.com/questions/1618240/how-to-support-both-ipv4-and-ipv6-connections
+	v6only, err := syscall.GetsockoptInt(int(file.Fd()), syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY)
+	if err != nil {
+		return false, err
+	}
+	return v6only == 1, nil
+}
+
+func getUDPSocketName(conn *net.UDPConn) (syscall.Sockaddr, error) {
+	file, err := conn.File()
+	if err != nil {
+		return nil, err
+	}
+	return syscall.Getsockname(int(file.Fd()))
+}

udp_other.go

@@ -0,0 +1,17 @@
+// +build !linux
+
+package dns
+
+import (
+	"net"
+	"syscall"
+)
+
+// These do nothing. See udp_linux.go for an example of how to implement this.
+
+// We tried to adhire to some kind of naming scheme.
+
+func setUDPSocketOptions4(conn *net.UDPConn) error                 { return nil }
+func setUDPSocketOptions6(conn *net.UDPConn) error                 { return nil }
+func getUDPSocketOptions6Only(conn *net.UDPConn) (bool, error)     { return false, nil }
+func getUDPSocketName(conn *net.UDPConn) (syscall.Sockaddr, error) { return nil, nil }

udp_windows.go

@@ -0,0 +1,34 @@
+// +build windows
+
+package dns
+
+import "net"
+
+type SessionUDP struct {
+	raddr *net.UDPAddr
+}
+
+// ReadFromSessionUDP acts just like net.UDPConn.ReadFrom(), but returns a session object instead of a
+// net.UDPAddr.
+func ReadFromSessionUDP(conn *net.UDPConn, b []byte) (int, *SessionUDP, error) {
+	n, raddr, err := conn.ReadFrom(b)
+	if err != nil {
+		return n, nil, err
+	}
+	session := &SessionUDP{raddr.(*net.UDPAddr)}
+	return n, session, err
+}
+
+// WriteToSessionUDP acts just like net.UDPConn.WritetTo(), but uses a *SessionUDP instead of a net.Addr.
+func WriteToSessionUDP(conn *net.UDPConn, b []byte, session *SessionUDP) (int, error) {
+	n, err := conn.WriteTo(b, session.raddr)
+	return n, err
+}
+
+func (s *SessionUDP) RemoteAddr() net.Addr { return s.raddr }
+
+// setUDPSocketOptions sets the UDP socket options.
+// This function is implemented on a per platform basis. See udp_*.go for more details
+func setUDPSocketOptions(conn *net.UDPConn) error {
+	return nil
+}

update.go

@@ -0,0 +1,94 @@
+package dns
+
+// NameUsed sets the RRs in the prereq section to
+// "Name is in use" RRs. RFC 2136 section 2.4.4.
+func (u *Msg) NameUsed(rr []RR) {
+	u.Answer = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Answer[i] = &ANY{Hdr: RR_Header{Name: r.Header().Name, Ttl: 0, Rrtype: TypeANY, Class: ClassANY}}
+	}
+}
+
+// NameNotUsed sets the RRs in the prereq section to
+// "Name is in not use" RRs. RFC 2136 section 2.4.5.
+func (u *Msg) NameNotUsed(rr []RR) {
+	u.Answer = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Answer[i] = &ANY{Hdr: RR_Header{Name: r.Header().Name, Ttl: 0, Rrtype: TypeANY, Class: ClassNONE}}
+	}
+}
+
+// Used sets the RRs in the prereq section to
+// "RRset exists (value dependent -- with rdata)" RRs. RFC 2136 section 2.4.2.
+func (u *Msg) Used(rr []RR) {
+	if len(u.Question) == 0 {
+		panic("dns: empty question section")
+	}
+	u.Answer = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Answer[i] = r
+		u.Answer[i].Header().Class = u.Question[0].Qclass
+	}
+}
+
+// RRsetUsed sets the RRs in the prereq section to
+// "RRset exists (value independent -- no rdata)" RRs. RFC 2136 section 2.4.1.
+func (u *Msg) RRsetUsed(rr []RR) {
+	u.Answer = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Answer[i] = r
+		u.Answer[i].Header().Class = ClassANY
+		u.Answer[i].Header().Ttl = 0
+		u.Answer[i].Header().Rdlength = 0
+	}
+}
+
+// RRsetNotUsed sets the RRs in the prereq section to
+// "RRset does not exist" RRs. RFC 2136 section 2.4.3.
+func (u *Msg) RRsetNotUsed(rr []RR) {
+	u.Answer = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Answer[i] = r
+		u.Answer[i].Header().Class = ClassNONE
+		u.Answer[i].Header().Rdlength = 0
+		u.Answer[i].Header().Ttl = 0
+	}
+}
+
+// Insert creates a dynamic update packet that adds an complete RRset, see RFC 2136 section 2.5.1.
+func (u *Msg) Insert(rr []RR) {
+	if len(u.Question) == 0 {
+		panic("dns: empty question section")
+	}
+	u.Ns = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Ns[i] = r
+		u.Ns[i].Header().Class = u.Question[0].Qclass
+	}
+}
+
+// RemoveRRset creates a dynamic update packet that deletes an RRset, see RFC 2136 section 2.5.2.
+func (u *Msg) RemoveRRset(rr []RR) {
+	u.Ns = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Ns[i] = &ANY{Hdr: RR_Header{Name: r.Header().Name, Ttl: 0, Rrtype: r.Header().Rrtype, Class: ClassANY}}
+	}
+}
+
+// RemoveName creates a dynamic update packet that deletes all RRsets of a name, see RFC 2136 section 2.5.3
+func (u *Msg) RemoveName(rr []RR) {
+	u.Ns = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Ns[i] = &ANY{Hdr: RR_Header{Name: r.Header().Name, Ttl: 0, Rrtype: TypeANY, Class: ClassANY}}
+	}
+}
+
+// Remove creates a dynamic update packet deletes RR from the RRSset, see RFC 2136 section 2.5.4
+func (u *Msg) Remove(rr []RR) {
+	u.Ns = make([]RR, len(rr))
+	for i, r := range rr {
+		u.Ns[i] = r
+		u.Ns[i].Header().Class = ClassNONE
+		u.Ns[i].Header().Ttl = 0
+	}
+}

update_test.go

@@ -0,0 +1,85 @@
+package dns
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestDynamicUpdateParsing(t *testing.T) {
+	prefix := "example.com. IN "
+	for _, typ := range TypeToString {
+		if typ == "OPT" || typ == "AXFR" || typ == "IXFR" || typ == "ANY" || typ == "TKEY" ||
+			typ == "TSIG" || typ == "ISDN" || typ == "UNSPEC" || typ == "NULL" || typ == "ATMA" ||
+			typ == "Reserved" || typ == "None" || typ == "NXT" || typ == "MAILB" || typ == "MAILA" {
+			continue
+		}
+		r, err := NewRR(prefix + typ)
+		if err != nil {
+			t.Errorf("failure to parse: %s %s: %v", prefix, typ, err)
+		} else {
+			t.Logf("parsed: %s", r.String())
+		}
+	}
+}
+
+func TestDynamicUpdateUnpack(t *testing.T) {
+	// From https://github.com/miekg/dns/issues/150#issuecomment-62296803
+	// It should be an update message for the zone "example.",
+	// deleting the A RRset "example." and then adding an A record at "example.".
+	// class ANY, TYPE A
+	buf := []byte{171, 68, 40, 0, 0, 1, 0, 0, 0, 2, 0, 0, 7, 101, 120, 97, 109, 112, 108, 101, 0, 0, 6, 0, 1, 192, 12, 0, 1, 0, 255, 0, 0, 0, 0, 0, 0, 192, 12, 0, 1, 0, 1, 0, 0, 0, 0, 0, 4, 127, 0, 0, 1}
+	msg := new(Msg)
+	err := msg.Unpack(buf)
+	if err != nil {
+		t.Errorf("failed to unpack: %v\n%s", err, msg.String())
+	}
+}
+
+func TestDynamicUpdateZeroRdataUnpack(t *testing.T) {
+	m := new(Msg)
+	rr := &RR_Header{Name: ".", Rrtype: 0, Class: 1, Ttl: ^uint32(0), Rdlength: 0}
+	m.Answer = []RR{rr, rr, rr, rr, rr}
+	m.Ns = m.Answer
+	for n, s := range TypeToString {
+		rr.Rrtype = n
+		bytes, err := m.Pack()
+		if err != nil {
+			t.Errorf("failed to pack %s: %v", s, err)
+			continue
+		}
+		if err := new(Msg).Unpack(bytes); err != nil {
+			t.Errorf("failed to unpack %s: %v", s, err)
+		}
+	}
+}
+
+func TestRemoveRRset(t *testing.T) {
+	// Should add a zero data RR in Class ANY with a TTL of 0
+	// for each set mentioned in the RRs provided to it.
+	rr, err := NewRR(". 100 IN A 127.0.0.1")
+	if err != nil {
+		t.Fatalf("error constructing RR: %v", err)
+	}
+	m := new(Msg)
+	m.Ns = []RR{&RR_Header{Name: ".", Rrtype: TypeA, Class: ClassANY, Ttl: 0, Rdlength: 0}}
+	expectstr := m.String()
+	expect, err := m.Pack()
+	if err != nil {
+		t.Fatalf("error packing expected msg: %v", err)
+	}
+
+	m.Ns = nil
+	m.RemoveRRset([]RR{rr})
+	actual, err := m.Pack()
+	if err != nil {
+		t.Fatalf("error packing actual msg: %v", err)
+	}
+	if !bytes.Equal(actual, expect) {
+		tmp := new(Msg)
+		if err := tmp.Unpack(actual); err != nil {
+			t.Fatalf("error unpacking actual msg: %v", err)
+		}
+		t.Errorf("expected msg:\n%s", expectstr)
+		t.Errorf("actual msg:\n%v", tmp)
+	}
+}

xfr.go

@@ -0,0 +1,244 @@
+package dns
+
+import (
+	"time"
+)
+
+// Envelope is used when doing a zone transfer with a remote server.
+type Envelope struct {
+	RR    []RR  // The set of RRs in the answer section of the xfr reply message.
+	Error error // If something went wrong, this contains the error.
+}
+
+// A Transfer defines parameters that are used during a zone transfer.
+type Transfer struct {
+	*Conn
+	DialTimeout    time.Duration     // net.DialTimeout, defaults to 2 seconds
+	ReadTimeout    time.Duration     // net.Conn.SetReadTimeout value for connections, defaults to 2 seconds
+	WriteTimeout   time.Duration     // net.Conn.SetWriteTimeout value for connections, defaults to 2 seconds
+	TsigSecret     map[string]string // Secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be fully qualified
+	tsigTimersOnly bool
+}
+
+// Think we need to away to stop the transfer
+
+// In performs an incoming transfer with the server in a.
+// If you would like to set the source IP, or some other attribute
+// of a Dialer for a Transfer, you can do so by specifying the attributes
+// in the Transfer.Conn:
+//
+//	d := net.Dialer{LocalAddr: transfer_source}
+//	con, err := d.Dial("tcp", master)
+//	dnscon := &dns.Conn{Conn:con}
+//	transfer = &dns.Transfer{Conn: dnscon}
+//	channel, err := transfer.In(message, master)
+//
+func (t *Transfer) In(q *Msg, a string) (env chan *Envelope, err error) {
+	timeout := dnsTimeout
+	if t.DialTimeout != 0 {
+		timeout = t.DialTimeout
+	}
+	if t.Conn == nil {
+		t.Conn, err = DialTimeout("tcp", a, timeout)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if err := t.WriteMsg(q); err != nil {
+		return nil, err
+	}
+	env = make(chan *Envelope)
+	go func() {
+		if q.Question[0].Qtype == TypeAXFR {
+			go t.inAxfr(q.Id, env)
+			return
+		}
+		if q.Question[0].Qtype == TypeIXFR {
+			go t.inIxfr(q.Id, env)
+			return
+		}
+	}()
+	return env, nil
+}
+
+func (t *Transfer) inAxfr(id uint16, c chan *Envelope) {
+	first := true
+	defer t.Close()
+	defer close(c)
+	timeout := dnsTimeout
+	if t.ReadTimeout != 0 {
+		timeout = t.ReadTimeout
+	}
+	for {
+		t.Conn.SetReadDeadline(time.Now().Add(timeout))
+		in, err := t.ReadMsg()
+		if err != nil {
+			c <- &Envelope{nil, err}
+			return
+		}
+		if id != in.Id {
+			c <- &Envelope{in.Answer, ErrId}
+			return
+		}
+		if first {
+			if !isSOAFirst(in) {
+				c <- &Envelope{in.Answer, ErrSoa}
+				return
+			}
+			first = !first
+			// only one answer that is SOA, receive more
+			if len(in.Answer) == 1 {
+				t.tsigTimersOnly = true
+				c <- &Envelope{in.Answer, nil}
+				continue
+			}
+		}
+
+		if !first {
+			t.tsigTimersOnly = true // Subsequent envelopes use this.
+			if isSOALast(in) {
+				c <- &Envelope{in.Answer, nil}
+				return
+			}
+			c <- &Envelope{in.Answer, nil}
+		}
+	}
+}
+
+func (t *Transfer) inIxfr(id uint16, c chan *Envelope) {
+	serial := uint32(0) // The first serial seen is the current server serial
+	first := true
+	defer t.Close()
+	defer close(c)
+	timeout := dnsTimeout
+	if t.ReadTimeout != 0 {
+		timeout = t.ReadTimeout
+	}
+	for {
+		t.SetReadDeadline(time.Now().Add(timeout))
+		in, err := t.ReadMsg()
+		if err != nil {
+			c <- &Envelope{nil, err}
+			return
+		}
+		if id != in.Id {
+			c <- &Envelope{in.Answer, ErrId}
+			return
+		}
+		if first {
+			// A single SOA RR signals "no changes"
+			if len(in.Answer) == 1 && isSOAFirst(in) {
+				c <- &Envelope{in.Answer, nil}
+				return
+			}
+
+			// Check if the returned answer is ok
+			if !isSOAFirst(in) {
+				c <- &Envelope{in.Answer, ErrSoa}
+				return
+			}
+			// This serial is important
+			serial = in.Answer[0].(*SOA).Serial
+			first = !first
+		}
+
+		// Now we need to check each message for SOA records, to see what we need to do
+		if !first {
+			t.tsigTimersOnly = true
+			// If the last record in the IXFR contains the servers' SOA,  we should quit
+			if v, ok := in.Answer[len(in.Answer)-1].(*SOA); ok {
+				if v.Serial == serial {
+					c <- &Envelope{in.Answer, nil}
+					return
+				}
+			}
+			c <- &Envelope{in.Answer, nil}
+		}
+	}
+}
+
+// Out performs an outgoing transfer with the client connecting in w.
+// Basic use pattern:
+//
+//	ch := make(chan *dns.Envelope)
+//	tr := new(dns.Transfer)
+//	tr.Out(w, r, ch)
+//	c <- &dns.Envelope{RR: []dns.RR{soa, rr1, rr2, rr3, soa}}
+//	close(ch)
+//	w.Hijack()
+//	// w.Close() // Client closes connection
+//
+// The server is responsible for sending the correct sequence of RRs through the
+// channel ch.
+func (t *Transfer) Out(w ResponseWriter, q *Msg, ch chan *Envelope) error {
+	for x := range ch {
+		r := new(Msg)
+		// Compress?
+		r.SetReply(q)
+		r.Authoritative = true
+		// assume it fits TODO(miek): fix
+		r.Answer = append(r.Answer, x.RR...)
+		if err := w.WriteMsg(r); err != nil {
+			return err
+		}
+	}
+	w.TsigTimersOnly(true)
+	return nil
+}
+
+// ReadMsg reads a message from the transfer connection t.
+func (t *Transfer) ReadMsg() (*Msg, error) {
+	m := new(Msg)
+	p := make([]byte, MaxMsgSize)
+	n, err := t.Read(p)
+	if err != nil && n == 0 {
+		return nil, err
+	}
+	p = p[:n]
+	if err := m.Unpack(p); err != nil {
+		return nil, err
+	}
+	if ts := m.IsTsig(); ts != nil && t.TsigSecret != nil {
+		if _, ok := t.TsigSecret[ts.Hdr.Name]; !ok {
+			return m, ErrSecret
+		}
+		// Need to work on the original message p, as that was used to calculate the tsig.
+		err = TsigVerify(p, t.TsigSecret[ts.Hdr.Name], t.tsigRequestMAC, t.tsigTimersOnly)
+		t.tsigRequestMAC = ts.MAC
+	}
+	return m, err
+}
+
+// WriteMsg writes a message through the transfer connection t.
+func (t *Transfer) WriteMsg(m *Msg) (err error) {
+	var out []byte
+	if ts := m.IsTsig(); ts != nil && t.TsigSecret != nil {
+		if _, ok := t.TsigSecret[ts.Hdr.Name]; !ok {
+			return ErrSecret
+		}
+		out, t.tsigRequestMAC, err = TsigGenerate(m, t.TsigSecret[ts.Hdr.Name], t.tsigRequestMAC, t.tsigTimersOnly)
+	} else {
+		out, err = m.Pack()
+	}
+	if err != nil {
+		return err
+	}
+	if _, err = t.Write(out); err != nil {
+		return err
+	}
+	return nil
+}
+
+func isSOAFirst(in *Msg) bool {
+	if len(in.Answer) > 0 {
+		return in.Answer[0].Header().Rrtype == TypeSOA
+	}
+	return false
+}
+
+func isSOALast(in *Msg) bool {
+	if len(in.Answer) > 0 {
+		return in.Answer[len(in.Answer)-1].Header().Rrtype == TypeSOA
+	}
+	return false
+}

xfr_test.go

@@ -0,0 +1,161 @@
+// +build net
+
+package dns
+
+import (
+	"net"
+	"testing"
+	"time"
+)
+
+func getIP(s string) string {
+	a, err := net.LookupAddr(s)
+	if err != nil {
+		return ""
+	}
+	return a[0]
+}
+
+// flaky, need to setup local server and test from
+// that.
+func TestAXFR_Miek(t *testing.T) {
+	// This test runs against a server maintained by Miek
+	if testing.Short() {
+		return
+	}
+	m := new(Msg)
+	m.SetAxfr("miek.nl.")
+
+	server := getIP("linode.atoom.net")
+
+	tr := new(Transfer)
+
+	if a, err := tr.In(m, net.JoinHostPort(server, "53")); err != nil {
+		t.Fatal("failed to setup axfr: ", err)
+	} else {
+		for ex := range a {
+			if ex.Error != nil {
+				t.Errorf("error %v", ex.Error)
+				break
+			}
+			for _, rr := range ex.RR {
+				t.Log(rr.String())
+			}
+		}
+	}
+}
+
+// fails.
+func TestAXFR_NLNL_MultipleEnvelopes(t *testing.T) {
+	// This test runs against a server maintained by NLnet Labs
+	if testing.Short() {
+		return
+	}
+	m := new(Msg)
+	m.SetAxfr("nlnetlabs.nl.")
+
+	server := getIP("open.nlnetlabs.nl.")
+
+	tr := new(Transfer)
+	if a, err := tr.In(m, net.JoinHostPort(server, "53")); err != nil {
+		t.Fatalf("failed to setup axfr %v for server: %v", err, server)
+	} else {
+		for ex := range a {
+			if ex.Error != nil {
+				t.Errorf("error %v", ex.Error)
+				break
+			}
+		}
+	}
+}
+
+func TestAXFR_Miek_Tsig(t *testing.T) {
+	// This test runs against a server maintained by Miek
+	if testing.Short() {
+		return
+	}
+	m := new(Msg)
+	m.SetAxfr("example.nl.")
+	m.SetTsig("axfr.", HmacMD5, 300, time.Now().Unix())
+
+	tr := new(Transfer)
+	tr.TsigSecret = map[string]string{"axfr.": "so6ZGir4GPAqINNh9U5c3A=="}
+
+	if a, err := tr.In(m, "176.58.119.54:53"); err != nil {
+		t.Fatal("failed to setup axfr: ", err)
+	} else {
+		for ex := range a {
+			if ex.Error != nil {
+				t.Errorf("error %v", ex.Error)
+				break
+			}
+			for _, rr := range ex.RR {
+				t.Log(rr.String())
+			}
+		}
+	}
+}
+
+func TestAXFR_SIDN_NSD3_NONE(t *testing.T)   { testAXFRSIDN(t, "nsd", "") }
+func TestAXFR_SIDN_NSD3_MD5(t *testing.T)    { testAXFRSIDN(t, "nsd", HmacMD5) }
+func TestAXFR_SIDN_NSD3_SHA1(t *testing.T)   { testAXFRSIDN(t, "nsd", HmacSHA1) }
+func TestAXFR_SIDN_NSD3_SHA256(t *testing.T) { testAXFRSIDN(t, "nsd", HmacSHA256) }
+
+func TestAXFR_SIDN_NSD4_NONE(t *testing.T)   { testAXFRSIDN(t, "nsd4", "") }
+func TestAXFR_SIDN_NSD4_MD5(t *testing.T)    { testAXFRSIDN(t, "nsd4", HmacMD5) }
+func TestAXFR_SIDN_NSD4_SHA1(t *testing.T)   { testAXFRSIDN(t, "nsd4", HmacSHA1) }
+func TestAXFR_SIDN_NSD4_SHA256(t *testing.T) { testAXFRSIDN(t, "nsd4", HmacSHA256) }
+
+func TestAXFR_SIDN_BIND9_NONE(t *testing.T)   { testAXFRSIDN(t, "bind9", "") }
+func TestAXFR_SIDN_BIND9_MD5(t *testing.T)    { testAXFRSIDN(t, "bind9", HmacMD5) }
+func TestAXFR_SIDN_BIND9_SHA1(t *testing.T)   { testAXFRSIDN(t, "bind9", HmacSHA1) }
+func TestAXFR_SIDN_BIND9_SHA256(t *testing.T) { testAXFRSIDN(t, "bind9", HmacSHA256) }
+
+func TestAXFR_SIDN_KNOT_NONE(t *testing.T)   { testAXFRSIDN(t, "knot", "") }
+func TestAXFR_SIDN_KNOT_MD5(t *testing.T)    { testAXFRSIDN(t, "knot", HmacMD5) }
+func TestAXFR_SIDN_KNOT_SHA1(t *testing.T)   { testAXFRSIDN(t, "knot", HmacSHA1) }
+func TestAXFR_SIDN_KNOT_SHA256(t *testing.T) { testAXFRSIDN(t, "knot", HmacSHA256) }
+
+func TestAXFR_SIDN_POWERDNS_NONE(t *testing.T)   { testAXFRSIDN(t, "powerdns", "") }
+func TestAXFR_SIDN_POWERDNS_MD5(t *testing.T)    { testAXFRSIDN(t, "powerdns", HmacMD5) }
+func TestAXFR_SIDN_POWERDNS_SHA1(t *testing.T)   { testAXFRSIDN(t, "powerdns", HmacSHA1) }
+func TestAXFR_SIDN_POWERDNS_SHA256(t *testing.T) { testAXFRSIDN(t, "powerdns", HmacSHA256) }
+
+func TestAXFR_SIDN_YADIFA_NONE(t *testing.T)   { testAXFRSIDN(t, "yadifa", "") }
+func TestAXFR_SIDN_YADIFA_MD5(t *testing.T)    { testAXFRSIDN(t, "yadifa", HmacMD5) }
+func TestAXFR_SIDN_YADIFA_SHA1(t *testing.T)   { testAXFRSIDN(t, "yadifa", HmacSHA1) }
+func TestAXFR_SIDN_YADIFA_SHA256(t *testing.T) { testAXFRSIDN(t, "yadifa", HmacSHA256) }
+
+func testAXFRSIDN(t *testing.T, host, alg string) {
+	// This tests run against a server maintained by SIDN labs, see:
+	// https://workbench.sidnlabs.nl/
+	if testing.Short() {
+		return
+	}
+	x := new(Transfer)
+	x.TsigSecret = map[string]string{
+		"wb_md5.":          "Wu/utSasZUkoeCNku152Zw==",
+		"wb_sha1_longkey.": "uhMpEhPq/RAD9Bt4mqhfmi+7ZdKmjLQb/lcrqYPXR4s/nnbsqw==",
+		"wb_sha256.":       "npfrIJjt/MJOjGJoBNZtsjftKMhkSpIYMv2RzRZt1f8=",
+	}
+	keyname := map[string]string{
+		HmacMD5:    "wb_md5.",
+		HmacSHA1:   "wb_sha1_longkey.",
+		HmacSHA256: "wb_sha256.",
+	}[alg]
+
+	m := new(Msg)
+	m.SetAxfr("types.wb.sidnlabs.nl.")
+	if keyname != "" {
+		m.SetTsig(keyname, alg, 300, time.Now().Unix())
+	}
+	c, err := x.In(m, host+".sidnlabs.nl:53")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for e := range c {
+		if e.Error != nil {
+			t.Fatal(e.Error)
+		}
+	}
+}

zgenerate.go

@@ -0,0 +1,158 @@
+package dns
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// Parse the $GENERATE statement as used in BIND9 zones.
+// See http://www.zytrax.com/books/dns/ch8/generate.html for instance.
+// We are called after '$GENERATE '. After which we expect:
+// * the range (12-24/2)
+// * lhs (ownername)
+// * [[ttl][class]]
+// * type
+// * rhs (rdata)
+// But we are lazy here, only the range is parsed *all* occurrences
+// of $ after that are interpreted.
+// Any error are returned as a string value, the empty string signals
+// "no error".
+func generate(l lex, c chan lex, t chan *Token, o string) string {
+	step := 1
+	if i := strings.IndexAny(l.token, "/"); i != -1 {
+		if i+1 == len(l.token) {
+			return "bad step in $GENERATE range"
+		}
+		if s, e := strconv.Atoi(l.token[i+1:]); e == nil {
+			if s < 0 {
+				return "bad step in $GENERATE range"
+			}
+			step = s
+		} else {
+			return "bad step in $GENERATE range"
+		}
+		l.token = l.token[:i]
+	}
+	sx := strings.SplitN(l.token, "-", 2)
+	if len(sx) != 2 {
+		return "bad start-stop in $GENERATE range"
+	}
+	start, err := strconv.Atoi(sx[0])
+	if err != nil {
+		return "bad start in $GENERATE range"
+	}
+	end, err := strconv.Atoi(sx[1])
+	if err != nil {
+		return "bad stop in $GENERATE range"
+	}
+	if end < 0 || start < 0 || end < start {
+		return "bad range in $GENERATE range"
+	}
+
+	<-c // _BLANK
+	// Create a complete new string, which we then parse again.
+	s := ""
+BuildRR:
+	l = <-c
+	if l.value != zNewline && l.value != zEOF {
+		s += l.token
+		goto BuildRR
+	}
+	for i := start; i <= end; i += step {
+		var (
+			escape bool
+			dom    bytes.Buffer
+			mod    string
+			err    string
+			offset int
+		)
+
+		for j := 0; j < len(s); j++ { // No 'range' because we need to jump around
+			switch s[j] {
+			case '\\':
+				if escape {
+					dom.WriteByte('\\')
+					escape = false
+					continue
+				}
+				escape = true
+			case '$':
+				mod = "%d"
+				offset = 0
+				if escape {
+					dom.WriteByte('$')
+					escape = false
+					continue
+				}
+				escape = false
+				if j+1 >= len(s) { // End of the string
+					dom.WriteString(fmt.Sprintf(mod, i+offset))
+					continue
+				} else {
+					if s[j+1] == '$' {
+						dom.WriteByte('$')
+						j++
+						continue
+					}
+				}
+				// Search for { and }
+				if s[j+1] == '{' { // Modifier block
+					sep := strings.Index(s[j+2:], "}")
+					if sep == -1 {
+						return "bad modifier in $GENERATE"
+					}
+					mod, offset, err = modToPrintf(s[j+2 : j+2+sep])
+					if err != "" {
+						return err
+					}
+					j += 2 + sep // Jump to it
+				}
+				dom.WriteString(fmt.Sprintf(mod, i+offset))
+			default:
+				if escape { // Pretty useless here
+					escape = false
+					continue
+				}
+				dom.WriteByte(s[j])
+			}
+		}
+		// Re-parse the RR and send it on the current channel t
+		rx, e := NewRR("$ORIGIN " + o + "\n" + dom.String())
+		if e != nil {
+			return e.(*ParseError).err
+		}
+		t <- &Token{RR: rx}
+		// Its more efficient to first built the rrlist and then parse it in
+		// one go! But is this a problem?
+	}
+	return ""
+}
+
+// Convert a $GENERATE modifier 0,0,d to something Printf can deal with.
+func modToPrintf(s string) (string, int, string) {
+	xs := strings.SplitN(s, ",", 3)
+	if len(xs) != 3 {
+		return "", 0, "bad modifier in $GENERATE"
+	}
+	// xs[0] is offset, xs[1] is width, xs[2] is base
+	if xs[2] != "o" && xs[2] != "d" && xs[2] != "x" && xs[2] != "X" {
+		return "", 0, "bad base in $GENERATE"
+	}
+	offset, err := strconv.Atoi(xs[0])
+	if err != nil || offset > 255 {
+		return "", 0, "bad offset in $GENERATE"
+	}
+	width, err := strconv.Atoi(xs[1])
+	if err != nil || width > 255 {
+		return "", offset, "bad width in $GENERATE"
+	}
+	switch {
+	case width < 0:
+		return "", offset, "bad width in $GENERATE"
+	case width == 0:
+		return "%" + xs[1] + xs[2], offset, ""
+	}
+	return "%0" + xs[1] + xs[2], offset, ""
+}

zscan.go

@@ -0,0 +1,974 @@
+package dns
+
+import (
+	"io"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type debugging bool
+
+const debug debugging = false
+
+func (d debugging) Printf(format string, args ...interface{}) {
+	if d {
+		log.Printf(format, args...)
+	}
+}
+
+const maxTok = 2048 // Largest token we can return.
+const maxUint16 = 1<<16 - 1
+
+// Tokinize a RFC 1035 zone file. The tokenizer will normalize it:
+// * Add ownernames if they are left blank;
+// * Suppress sequences of spaces;
+// * Make each RR fit on one line (_NEWLINE is send as last)
+// * Handle comments: ;
+// * Handle braces - anywhere.
+const (
+	// Zonefile
+	zEOF = iota
+	zString
+	zBlank
+	zQuote
+	zNewline
+	zRrtpe
+	zOwner
+	zClass
+	zDirOrigin   // $ORIGIN
+	zDirTtl      // $TTL
+	zDirInclude  // $INCLUDE
+	zDirGenerate // $GENERATE
+
+	// Privatekey file
+	zValue
+	zKey
+
+	zExpectOwnerDir      // Ownername
+	zExpectOwnerBl       // Whitespace after the ownername
+	zExpectAny           // Expect rrtype, ttl or class
+	zExpectAnyNoClass    // Expect rrtype or ttl
+	zExpectAnyNoClassBl  // The whitespace after _EXPECT_ANY_NOCLASS
+	zExpectAnyNoTtl      // Expect rrtype or class
+	zExpectAnyNoTtlBl    // Whitespace after _EXPECT_ANY_NOTTL
+	zExpectRrtype        // Expect rrtype
+	zExpectRrtypeBl      // Whitespace BEFORE rrtype
+	zExpectRdata         // The first element of the rdata
+	zExpectDirTtlBl      // Space after directive $TTL
+	zExpectDirTtl        // Directive $TTL
+	zExpectDirOriginBl   // Space after directive $ORIGIN
+	zExpectDirOrigin     // Directive $ORIGIN
+	zExpectDirIncludeBl  // Space after directive $INCLUDE
+	zExpectDirInclude    // Directive $INCLUDE
+	zExpectDirGenerate   // Directive $GENERATE
+	zExpectDirGenerateBl // Space after directive $GENERATE
+)
+
+// ParseError is a parsing error. It contains the parse error and the location in the io.Reader
+// where the error occurred.
+type ParseError struct {
+	file string
+	err  string
+	lex  lex
+}
+
+func (e *ParseError) Error() (s string) {
+	if e.file != "" {
+		s = e.file + ": "
+	}
+	s += "dns: " + e.err + ": " + strconv.QuoteToASCII(e.lex.token) + " at line: " +
+		strconv.Itoa(e.lex.line) + ":" + strconv.Itoa(e.lex.column)
+	return
+}
+
+type lex struct {
+	token      string // text of the token
+	tokenUpper string // uppercase text of the token
+	length     int    // length of the token
+	err        bool   // when true, token text has lexer error
+	value      uint8  // value: zString, _BLANK, etc.
+	line       int    // line in the file
+	column     int    // column in the file
+	torc       uint16 // type or class as parsed in the lexer, we only need to look this up in the grammar
+	comment    string // any comment text seen
+}
+
+// Token holds the token that are returned when a zone file is parsed.
+type Token struct {
+	// The scanned resource record when error is not nil.
+	RR
+	// When an error occurred, this has the error specifics.
+	Error *ParseError
+	// A potential comment positioned after the RR and on the same line.
+	Comment string
+}
+
+// NewRR reads the RR contained in the string s. Only the first RR is
+// returned. If s contains no RR, return nil with no error. The class
+// defaults to IN and TTL defaults to 3600. The full zone file syntax
+// like $TTL, $ORIGIN, etc. is supported. All fields of the returned
+// RR are set, except RR.Header().Rdlength which is set to 0.
+func NewRR(s string) (RR, error) {
+	if len(s) > 0 && s[len(s)-1] != '\n' { // We need a closing newline
+		return ReadRR(strings.NewReader(s+"\n"), "")
+	}
+	return ReadRR(strings.NewReader(s), "")
+}
+
+// ReadRR reads the RR contained in q.
+// See NewRR for more documentation.
+func ReadRR(q io.Reader, filename string) (RR, error) {
+	r := <-parseZoneHelper(q, ".", filename, 1)
+	if r == nil {
+		return nil, nil
+	}
+
+	if r.Error != nil {
+		return nil, r.Error
+	}
+	return r.RR, nil
+}
+
+// ParseZone reads a RFC 1035 style zonefile from r. It returns *Tokens on the
+// returned channel, which consist out the parsed RR, a potential comment or an error.
+// If there is an error the RR is nil. The string file is only used
+// in error reporting. The string origin is used as the initial origin, as
+// if the file would start with: $ORIGIN origin .
+// The directives $INCLUDE, $ORIGIN, $TTL and $GENERATE are supported.
+// The channel t is closed by ParseZone when the end of r is reached.
+//
+// Basic usage pattern when reading from a string (z) containing the
+// zone data:
+//
+//	for x := range dns.ParseZone(strings.NewReader(z), "", "") {
+//		if x.Error != nil {
+//                  // log.Println(x.Error)
+//              } else {
+//                  // Do something with x.RR
+//              }
+//	}
+//
+// Comments specified after an RR (and on the same line!) are returned too:
+//
+//	foo. IN A 10.0.0.1 ; this is a comment
+//
+// The text "; this is comment" is returned in Token.Comment. Comments inside the
+// RR are discarded. Comments on a line by themselves are discarded too.
+func ParseZone(r io.Reader, origin, file string) chan *Token {
+	return parseZoneHelper(r, origin, file, 10000)
+}
+
+func parseZoneHelper(r io.Reader, origin, file string, chansize int) chan *Token {
+	t := make(chan *Token, chansize)
+	go parseZone(r, origin, file, t, 0)
+	return t
+}
+
+func parseZone(r io.Reader, origin, f string, t chan *Token, include int) {
+	defer func() {
+		if include == 0 {
+			close(t)
+		}
+	}()
+	s := scanInit(r)
+	c := make(chan lex)
+	// Start the lexer
+	go zlexer(s, c)
+	// 6 possible beginnings of a line, _ is a space
+	// 0. zRRTYPE                              -> all omitted until the rrtype
+	// 1. zOwner _ zRrtype                     -> class/ttl omitted
+	// 2. zOwner _ zString _ zRrtype           -> class omitted
+	// 3. zOwner _ zString _ zClass  _ zRrtype -> ttl/class
+	// 4. zOwner _ zClass  _ zRrtype           -> ttl omitted
+	// 5. zOwner _ zClass  _ zString _ zRrtype -> class/ttl (reversed)
+	// After detecting these, we know the zRrtype so we can jump to functions
+	// handling the rdata for each of these types.
+
+	if origin == "" {
+		origin = "."
+	}
+	origin = Fqdn(origin)
+	if _, ok := IsDomainName(origin); !ok {
+		t <- &Token{Error: &ParseError{f, "bad initial origin name", lex{}}}
+		return
+	}
+
+	st := zExpectOwnerDir // initial state
+	var h RR_Header
+	var defttl uint32 = defaultTtl
+	var prevName string
+	for l := range c {
+		// Lexer spotted an error already
+		if l.err == true {
+			t <- &Token{Error: &ParseError{f, l.token, l}}
+			return
+
+		}
+		switch st {
+		case zExpectOwnerDir:
+			// We can also expect a directive, like $TTL or $ORIGIN
+			h.Ttl = defttl
+			h.Class = ClassINET
+			switch l.value {
+			case zNewline:
+				st = zExpectOwnerDir
+			case zOwner:
+				h.Name = l.token
+				if l.token[0] == '@' {
+					h.Name = origin
+					prevName = h.Name
+					st = zExpectOwnerBl
+					break
+				}
+				if h.Name[l.length-1] != '.' {
+					h.Name = appendOrigin(h.Name, origin)
+				}
+				_, ok := IsDomainName(l.token)
+				if !ok {
+					t <- &Token{Error: &ParseError{f, "bad owner name", l}}
+					return
+				}
+				prevName = h.Name
+				st = zExpectOwnerBl
+			case zDirTtl:
+				st = zExpectDirTtlBl
+			case zDirOrigin:
+				st = zExpectDirOriginBl
+			case zDirInclude:
+				st = zExpectDirIncludeBl
+			case zDirGenerate:
+				st = zExpectDirGenerateBl
+			case zRrtpe:
+				h.Name = prevName
+				h.Rrtype = l.torc
+				st = zExpectRdata
+			case zClass:
+				h.Name = prevName
+				h.Class = l.torc
+				st = zExpectAnyNoClassBl
+			case zBlank:
+				// Discard, can happen when there is nothing on the
+				// line except the RR type
+			case zString:
+				ttl, ok := stringToTtl(l.token)
+				if !ok {
+					t <- &Token{Error: &ParseError{f, "not a TTL", l}}
+					return
+				}
+				h.Ttl = ttl
+				// Don't about the defttl, we should take the $TTL value
+				// defttl = ttl
+				st = zExpectAnyNoTtlBl
+
+			default:
+				t <- &Token{Error: &ParseError{f, "syntax error at beginning", l}}
+				return
+			}
+		case zExpectDirIncludeBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank after $INCLUDE-directive", l}}
+				return
+			}
+			st = zExpectDirInclude
+		case zExpectDirInclude:
+			if l.value != zString {
+				t <- &Token{Error: &ParseError{f, "expecting $INCLUDE value, not this...", l}}
+				return
+			}
+			neworigin := origin // There may be optionally a new origin set after the filename, if not use current one
+			l := <-c
+			switch l.value {
+			case zBlank:
+				l := <-c
+				if l.value == zString {
+					if _, ok := IsDomainName(l.token); !ok || l.length == 0 || l.err {
+						t <- &Token{Error: &ParseError{f, "bad origin name", l}}
+						return
+					}
+					// a new origin is specified.
+					if l.token[l.length-1] != '.' {
+						if origin != "." { // Prevent .. endings
+							neworigin = l.token + "." + origin
+						} else {
+							neworigin = l.token + origin
+						}
+					} else {
+						neworigin = l.token
+					}
+				}
+			case zNewline, zEOF:
+				// Ok
+			default:
+				t <- &Token{Error: &ParseError{f, "garbage after $INCLUDE", l}}
+				return
+			}
+			// Start with the new file
+			r1, e1 := os.Open(l.token)
+			if e1 != nil {
+				t <- &Token{Error: &ParseError{f, "failed to open `" + l.token + "'", l}}
+				return
+			}
+			if include+1 > 7 {
+				t <- &Token{Error: &ParseError{f, "too deeply nested $INCLUDE", l}}
+				return
+			}
+			parseZone(r1, l.token, neworigin, t, include+1)
+			st = zExpectOwnerDir
+		case zExpectDirTtlBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank after $TTL-directive", l}}
+				return
+			}
+			st = zExpectDirTtl
+		case zExpectDirTtl:
+			if l.value != zString {
+				t <- &Token{Error: &ParseError{f, "expecting $TTL value, not this...", l}}
+				return
+			}
+			if e, _ := slurpRemainder(c, f); e != nil {
+				t <- &Token{Error: e}
+				return
+			}
+			ttl, ok := stringToTtl(l.token)
+			if !ok {
+				t <- &Token{Error: &ParseError{f, "expecting $TTL value, not this...", l}}
+				return
+			}
+			defttl = ttl
+			st = zExpectOwnerDir
+		case zExpectDirOriginBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank after $ORIGIN-directive", l}}
+				return
+			}
+			st = zExpectDirOrigin
+		case zExpectDirOrigin:
+			if l.value != zString {
+				t <- &Token{Error: &ParseError{f, "expecting $ORIGIN value, not this...", l}}
+				return
+			}
+			if e, _ := slurpRemainder(c, f); e != nil {
+				t <- &Token{Error: e}
+			}
+			if _, ok := IsDomainName(l.token); !ok {
+				t <- &Token{Error: &ParseError{f, "bad origin name", l}}
+				return
+			}
+			if l.token[l.length-1] != '.' {
+				if origin != "." { // Prevent .. endings
+					origin = l.token + "." + origin
+				} else {
+					origin = l.token + origin
+				}
+			} else {
+				origin = l.token
+			}
+			st = zExpectOwnerDir
+		case zExpectDirGenerateBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank after $GENERATE-directive", l}}
+				return
+			}
+			st = zExpectDirGenerate
+		case zExpectDirGenerate:
+			if l.value != zString {
+				t <- &Token{Error: &ParseError{f, "expecting $GENERATE value, not this...", l}}
+				return
+			}
+			if e := generate(l, c, t, origin); e != "" {
+				t <- &Token{Error: &ParseError{f, e, l}}
+				return
+			}
+			st = zExpectOwnerDir
+		case zExpectOwnerBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank after owner", l}}
+				return
+			}
+			st = zExpectAny
+		case zExpectAny:
+			switch l.value {
+			case zRrtpe:
+				h.Rrtype = l.torc
+				st = zExpectRdata
+			case zClass:
+				h.Class = l.torc
+				st = zExpectAnyNoClassBl
+			case zString:
+				ttl, ok := stringToTtl(l.token)
+				if !ok {
+					t <- &Token{Error: &ParseError{f, "not a TTL", l}}
+					return
+				}
+				h.Ttl = ttl
+				// defttl = ttl // don't set the defttl here
+				st = zExpectAnyNoTtlBl
+			default:
+				t <- &Token{Error: &ParseError{f, "expecting RR type, TTL or class, not this...", l}}
+				return
+			}
+		case zExpectAnyNoClassBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank before class", l}}
+				return
+			}
+			st = zExpectAnyNoClass
+		case zExpectAnyNoTtlBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank before TTL", l}}
+				return
+			}
+			st = zExpectAnyNoTtl
+		case zExpectAnyNoTtl:
+			switch l.value {
+			case zClass:
+				h.Class = l.torc
+				st = zExpectRrtypeBl
+			case zRrtpe:
+				h.Rrtype = l.torc
+				st = zExpectRdata
+			default:
+				t <- &Token{Error: &ParseError{f, "expecting RR type or class, not this...", l}}
+				return
+			}
+		case zExpectAnyNoClass:
+			switch l.value {
+			case zString:
+				ttl, ok := stringToTtl(l.token)
+				if !ok {
+					t <- &Token{Error: &ParseError{f, "not a TTL", l}}
+					return
+				}
+				h.Ttl = ttl
+				// defttl = ttl // don't set the def ttl anymore
+				st = zExpectRrtypeBl
+			case zRrtpe:
+				h.Rrtype = l.torc
+				st = zExpectRdata
+			default:
+				t <- &Token{Error: &ParseError{f, "expecting RR type or TTL, not this...", l}}
+				return
+			}
+		case zExpectRrtypeBl:
+			if l.value != zBlank {
+				t <- &Token{Error: &ParseError{f, "no blank before RR type", l}}
+				return
+			}
+			st = zExpectRrtype
+		case zExpectRrtype:
+			if l.value != zRrtpe {
+				t <- &Token{Error: &ParseError{f, "unknown RR type", l}}
+				return
+			}
+			h.Rrtype = l.torc
+			st = zExpectRdata
+		case zExpectRdata:
+			r, e, c1 := setRR(h, c, origin, f)
+			if e != nil {
+				// If e.lex is nil than we have encounter a unknown RR type
+				// in that case we substitute our current lex token
+				if e.lex.token == "" && e.lex.value == 0 {
+					e.lex = l // Uh, dirty
+				}
+				t <- &Token{Error: e}
+				return
+			}
+			t <- &Token{RR: r, Comment: c1}
+			st = zExpectOwnerDir
+		}
+	}
+	// If we get here, we and the h.Rrtype is still zero, we haven't parsed anything, this
+	// is not an error, because an empty zone file is still a zone file.
+}
+
+// zlexer scans the sourcefile and returns tokens on the channel c.
+func zlexer(s *scan, c chan lex) {
+	var l lex
+	str := make([]byte, maxTok) // Should be enough for any token
+	stri := 0                   // Offset in str (0 means empty)
+	com := make([]byte, maxTok) // Hold comment text
+	comi := 0
+	quote := false
+	escape := false
+	space := false
+	commt := false
+	rrtype := false
+	owner := true
+	brace := 0
+	x, err := s.tokenText()
+	defer close(c)
+	for err == nil {
+		l.column = s.position.Column
+		l.line = s.position.Line
+		if stri >= maxTok {
+			l.token = "token length insufficient for parsing"
+			l.err = true
+			debug.Printf("[%+v]", l.token)
+			c <- l
+			return
+		}
+		if comi >= maxTok {
+			l.token = "comment length insufficient for parsing"
+			l.err = true
+			debug.Printf("[%+v]", l.token)
+			c <- l
+			return
+		}
+
+		switch x {
+		case ' ', '\t':
+			if escape {
+				escape = false
+				str[stri] = x
+				stri++
+				break
+			}
+			if quote {
+				// Inside quotes this is legal
+				str[stri] = x
+				stri++
+				break
+			}
+			if commt {
+				com[comi] = x
+				comi++
+				break
+			}
+			if stri == 0 {
+				// Space directly in the beginning, handled in the grammar
+			} else if owner {
+				// If we have a string and its the first, make it an owner
+				l.value = zOwner
+				l.token = string(str[:stri])
+				l.tokenUpper = strings.ToUpper(l.token)
+				l.length = stri
+				// escape $... start with a \ not a $, so this will work
+				switch l.tokenUpper {
+				case "$TTL":
+					l.value = zDirTtl
+				case "$ORIGIN":
+					l.value = zDirOrigin
+				case "$INCLUDE":
+					l.value = zDirInclude
+				case "$GENERATE":
+					l.value = zDirGenerate
+				}
+				debug.Printf("[7 %+v]", l.token)
+				c <- l
+			} else {
+				l.value = zString
+				l.token = string(str[:stri])
+				l.tokenUpper = strings.ToUpper(l.token)
+				l.length = stri
+				if !rrtype {
+					if t, ok := StringToType[l.tokenUpper]; ok {
+						l.value = zRrtpe
+						l.torc = t
+						rrtype = true
+					} else {
+						if strings.HasPrefix(l.tokenUpper, "TYPE") {
+							t, ok := typeToInt(l.token)
+							if !ok {
+								l.token = "unknown RR type"
+								l.err = true
+								c <- l
+								return
+							}
+							l.value = zRrtpe
+							l.torc = t
+						}
+					}
+					if t, ok := StringToClass[l.tokenUpper]; ok {
+						l.value = zClass
+						l.torc = t
+					} else {
+						if strings.HasPrefix(l.tokenUpper, "CLASS") {
+							t, ok := classToInt(l.token)
+							if !ok {
+								l.token = "unknown class"
+								l.err = true
+								c <- l
+								return
+							}
+							l.value = zClass
+							l.torc = t
+						}
+					}
+				}
+				debug.Printf("[6 %+v]", l.token)
+				c <- l
+			}
+			stri = 0
+			// I reverse space stuff here
+			if !space && !commt {
+				l.value = zBlank
+				l.token = " "
+				l.length = 1
+				debug.Printf("[5 %+v]", l.token)
+				c <- l
+			}
+			owner = false
+			space = true
+		case ';':
+			if escape {
+				escape = false
+				str[stri] = x
+				stri++
+				break
+			}
+			if quote {
+				// Inside quotes this is legal
+				str[stri] = x
+				stri++
+				break
+			}
+			if stri > 0 {
+				l.value = zString
+				l.token = string(str[:stri])
+				l.length = stri
+				debug.Printf("[4 %+v]", l.token)
+				c <- l
+				stri = 0
+			}
+			commt = true
+			com[comi] = ';'
+			comi++
+		case '\r':
+			escape = false
+			if quote {
+				str[stri] = x
+				stri++
+				break
+			}
+			// discard if outside of quotes
+		case '\n':
+			escape = false
+			// Escaped newline
+			if quote {
+				str[stri] = x
+				stri++
+				break
+			}
+			// inside quotes this is legal
+			if commt {
+				// Reset a comment
+				commt = false
+				rrtype = false
+				stri = 0
+				// If not in a brace this ends the comment AND the RR
+				if brace == 0 {
+					owner = true
+					owner = true
+					l.value = zNewline
+					l.token = "\n"
+					l.length = 1
+					l.comment = string(com[:comi])
+					debug.Printf("[3 %+v %+v]", l.token, l.comment)
+					c <- l
+					l.comment = ""
+					comi = 0
+					break
+				}
+				com[comi] = ' ' // convert newline to space
+				comi++
+				break
+			}
+
+			if brace == 0 {
+				// If there is previous text, we should output it here
+				if stri != 0 {
+					l.value = zString
+					l.token = string(str[:stri])
+					l.tokenUpper = strings.ToUpper(l.token)
+
+					l.length = stri
+					if !rrtype {
+						if t, ok := StringToType[l.tokenUpper]; ok {
+							l.value = zRrtpe
+							l.torc = t
+							rrtype = true
+						}
+					}
+					debug.Printf("[2 %+v]", l.token)
+					c <- l
+				}
+				l.value = zNewline
+				l.token = "\n"
+				l.length = 1
+				debug.Printf("[1 %+v]", l.token)
+				c <- l
+				stri = 0
+				commt = false
+				rrtype = false
+				owner = true
+				comi = 0
+			}
+		case '\\':
+			// comments do not get escaped chars, everything is copied
+			if commt {
+				com[comi] = x
+				comi++
+				break
+			}
+			// something already escaped must be in string
+			if escape {
+				str[stri] = x
+				stri++
+				escape = false
+				break
+			}
+			// something escaped outside of string gets added to string
+			str[stri] = x
+			stri++
+			escape = true
+		case '"':
+			if commt {
+				com[comi] = x
+				comi++
+				break
+			}
+			if escape {
+				str[stri] = x
+				stri++
+				escape = false
+				break
+			}
+			space = false
+			// send previous gathered text and the quote
+			if stri != 0 {
+				l.value = zString
+				l.token = string(str[:stri])
+				l.length = stri
+
+				debug.Printf("[%+v]", l.token)
+				c <- l
+				stri = 0
+			}
+
+			// send quote itself as separate token
+			l.value = zQuote
+			l.token = "\""
+			l.length = 1
+			c <- l
+			quote = !quote
+		case '(', ')':
+			if commt {
+				com[comi] = x
+				comi++
+				break
+			}
+			if escape {
+				str[stri] = x
+				stri++
+				escape = false
+				break
+			}
+			if quote {
+				str[stri] = x
+				stri++
+				break
+			}
+			switch x {
+			case ')':
+				brace--
+				if brace < 0 {
+					l.token = "extra closing brace"
+					l.err = true
+					debug.Printf("[%+v]", l.token)
+					c <- l
+					return
+				}
+			case '(':
+				brace++
+			}
+		default:
+			escape = false
+			if commt {
+				com[comi] = x
+				comi++
+				break
+			}
+			str[stri] = x
+			stri++
+			space = false
+		}
+		x, err = s.tokenText()
+	}
+	if stri > 0 {
+		// Send remainder
+		l.token = string(str[:stri])
+		l.length = stri
+		l.value = zString
+		debug.Printf("[%+v]", l.token)
+		c <- l
+	}
+}
+
+// Extract the class number from CLASSxx
+func classToInt(token string) (uint16, bool) {
+	offset := 5
+	if len(token) < offset+1 {
+		return 0, false
+	}
+	class, ok := strconv.Atoi(token[offset:])
+	if ok != nil || class > maxUint16 {
+		return 0, false
+	}
+	return uint16(class), true
+}
+
+// Extract the rr number from TYPExxx
+func typeToInt(token string) (uint16, bool) {
+	offset := 4
+	if len(token) < offset+1 {
+		return 0, false
+	}
+	typ, ok := strconv.Atoi(token[offset:])
+	if ok != nil || typ > maxUint16 {
+		return 0, false
+	}
+	return uint16(typ), true
+}
+
+// Parse things like 2w, 2m, etc, Return the time in seconds.
+func stringToTtl(token string) (uint32, bool) {
+	s := uint32(0)
+	i := uint32(0)
+	for _, c := range token {
+		switch c {
+		case 's', 'S':
+			s += i
+			i = 0
+		case 'm', 'M':
+			s += i * 60
+			i = 0
+		case 'h', 'H':
+			s += i * 60 * 60
+			i = 0
+		case 'd', 'D':
+			s += i * 60 * 60 * 24
+			i = 0
+		case 'w', 'W':
+			s += i * 60 * 60 * 24 * 7
+			i = 0
+		case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+			i *= 10
+			i += uint32(c) - '0'
+		default:
+			return 0, false
+		}
+	}
+	return s + i, true
+}
+
+// Parse LOC records' <digits>[.<digits>][mM] into a
+// mantissa exponent format. Token should contain the entire
+// string (i.e. no spaces allowed)
+func stringToCm(token string) (e, m uint8, ok bool) {
+	if token[len(token)-1] == 'M' || token[len(token)-1] == 'm' {
+		token = token[0 : len(token)-1]
+	}
+	s := strings.SplitN(token, ".", 2)
+	var meters, cmeters, val int
+	var err error
+	switch len(s) {
+	case 2:
+		if cmeters, err = strconv.Atoi(s[1]); err != nil {
+			return
+		}
+		fallthrough
+	case 1:
+		if meters, err = strconv.Atoi(s[0]); err != nil {
+			return
+		}
+	case 0:
+		// huh?
+		return 0, 0, false
+	}
+	ok = true
+	if meters > 0 {
+		e = 2
+		val = meters
+	} else {
+		e = 0
+		val = cmeters
+	}
+	for val > 10 {
+		e++
+		val /= 10
+	}
+	if e > 9 {
+		ok = false
+	}
+	m = uint8(val)
+	return
+}
+
+func appendOrigin(name, origin string) string {
+	if origin == "." {
+		return name + origin
+	}
+	return name + "." + origin
+}
+
+// LOC record helper function
+func locCheckNorth(token string, latitude uint32) (uint32, bool) {
+	switch token {
+	case "n", "N":
+		return LOC_EQUATOR + latitude, true
+	case "s", "S":
+		return LOC_EQUATOR - latitude, true
+	}
+	return latitude, false
+}
+
+// LOC record helper function
+func locCheckEast(token string, longitude uint32) (uint32, bool) {
+	switch token {
+	case "e", "E":
+		return LOC_EQUATOR + longitude, true
+	case "w", "W":
+		return LOC_EQUATOR - longitude, true
+	}
+	return longitude, false
+}
+
+// "Eat" the rest of the "line". Return potential comments
+func slurpRemainder(c chan lex, f string) (*ParseError, string) {
+	l := <-c
+	com := ""
+	switch l.value {
+	case zBlank:
+		l = <-c
+		com = l.comment
+		if l.value != zNewline && l.value != zEOF {
+			return &ParseError{f, "garbage after rdata", l}, ""
+		}
+	case zNewline:
+		com = l.comment
+	case zEOF:
+	default:
+		return &ParseError{f, "garbage after rdata", l}, ""
+	}
+	return nil, com
+}
+
+// Parse a 64 bit-like ipv6 address: "0014:4fff:ff20:ee64"
+// Used for NID and L64 record.
+func stringToNodeID(l lex) (uint64, *ParseError) {
+	if len(l.token) < 19 {
+		return 0, &ParseError{l.token, "bad NID/L64 NodeID/Locator64", l}
+	}
+	// There must be three colons at fixes postitions, if not its a parse error
+	if l.token[4] != ':' && l.token[9] != ':' && l.token[14] != ':' {
+		return 0, &ParseError{l.token, "bad NID/L64 NodeID/Locator64", l}
+	}
+	s := l.token[0:4] + l.token[5:9] + l.token[10:14] + l.token[15:19]
+	u, e := strconv.ParseUint(s, 16, 64)
+	if e != nil {
+		return 0, &ParseError{l.token, "bad NID/L64 NodeID/Locator64", l}
+	}
+	return u, nil
+}

ztypes.go

@@ -0,0 +1,842 @@
+// *** DO NOT MODIFY ***
+// AUTOGENERATED BY go generate
+
+package dns
+
+import (
+	"encoding/base64"
+	"net"
+)
+
+// TypeToRR is a map of constructors for each RR type.
+var TypeToRR = map[uint16]func() RR{
+	TypeA:          func() RR { return new(A) },
+	TypeAAAA:       func() RR { return new(AAAA) },
+	TypeAFSDB:      func() RR { return new(AFSDB) },
+	TypeANY:        func() RR { return new(ANY) },
+	TypeCAA:        func() RR { return new(CAA) },
+	TypeCDNSKEY:    func() RR { return new(CDNSKEY) },
+	TypeCDS:        func() RR { return new(CDS) },
+	TypeCERT:       func() RR { return new(CERT) },
+	TypeCNAME:      func() RR { return new(CNAME) },
+	TypeDHCID:      func() RR { return new(DHCID) },
+	TypeDLV:        func() RR { return new(DLV) },
+	TypeDNAME:      func() RR { return new(DNAME) },
+	TypeDNSKEY:     func() RR { return new(DNSKEY) },
+	TypeDS:         func() RR { return new(DS) },
+	TypeEID:        func() RR { return new(EID) },
+	TypeEUI48:      func() RR { return new(EUI48) },
+	TypeEUI64:      func() RR { return new(EUI64) },
+	TypeGID:        func() RR { return new(GID) },
+	TypeGPOS:       func() RR { return new(GPOS) },
+	TypeHINFO:      func() RR { return new(HINFO) },
+	TypeHIP:        func() RR { return new(HIP) },
+	TypeIPSECKEY:   func() RR { return new(IPSECKEY) },
+	TypeKEY:        func() RR { return new(KEY) },
+	TypeKX:         func() RR { return new(KX) },
+	TypeL32:        func() RR { return new(L32) },
+	TypeL64:        func() RR { return new(L64) },
+	TypeLOC:        func() RR { return new(LOC) },
+	TypeLP:         func() RR { return new(LP) },
+	TypeMB:         func() RR { return new(MB) },
+	TypeMD:         func() RR { return new(MD) },
+	TypeMF:         func() RR { return new(MF) },
+	TypeMG:         func() RR { return new(MG) },
+	TypeMINFO:      func() RR { return new(MINFO) },
+	TypeMR:         func() RR { return new(MR) },
+	TypeMX:         func() RR { return new(MX) },
+	TypeNAPTR:      func() RR { return new(NAPTR) },
+	TypeNID:        func() RR { return new(NID) },
+	TypeNIMLOC:     func() RR { return new(NIMLOC) },
+	TypeNINFO:      func() RR { return new(NINFO) },
+	TypeNS:         func() RR { return new(NS) },
+	TypeNSAPPTR:    func() RR { return new(NSAPPTR) },
+	TypeNSEC:       func() RR { return new(NSEC) },
+	TypeNSEC3:      func() RR { return new(NSEC3) },
+	TypeNSEC3PARAM: func() RR { return new(NSEC3PARAM) },
+	TypeOPENPGPKEY: func() RR { return new(OPENPGPKEY) },
+	TypeOPT:        func() RR { return new(OPT) },
+	TypePTR:        func() RR { return new(PTR) },
+	TypePX:         func() RR { return new(PX) },
+	TypeRKEY:       func() RR { return new(RKEY) },
+	TypeRP:         func() RR { return new(RP) },
+	TypeRRSIG:      func() RR { return new(RRSIG) },
+	TypeRT:         func() RR { return new(RT) },
+	TypeSIG:        func() RR { return new(SIG) },
+	TypeSOA:        func() RR { return new(SOA) },
+	TypeSPF:        func() RR { return new(SPF) },
+	TypeSRV:        func() RR { return new(SRV) },
+	TypeSSHFP:      func() RR { return new(SSHFP) },
+	TypeTA:         func() RR { return new(TA) },
+	TypeTALINK:     func() RR { return new(TALINK) },
+	TypeTKEY:       func() RR { return new(TKEY) },
+	TypeTLSA:       func() RR { return new(TLSA) },
+	TypeTSIG:       func() RR { return new(TSIG) },
+	TypeTXT:        func() RR { return new(TXT) },
+	TypeUID:        func() RR { return new(UID) },
+	TypeUINFO:      func() RR { return new(UINFO) },
+	TypeURI:        func() RR { return new(URI) },
+	TypeWKS:        func() RR { return new(WKS) },
+	TypeX25:        func() RR { return new(X25) },
+}
+
+// TypeToString is a map of strings for each RR type.
+var TypeToString = map[uint16]string{
+	TypeA:          "A",
+	TypeAAAA:       "AAAA",
+	TypeAFSDB:      "AFSDB",
+	TypeANY:        "ANY",
+	TypeATMA:       "ATMA",
+	TypeAXFR:       "AXFR",
+	TypeCAA:        "CAA",
+	TypeCDNSKEY:    "CDNSKEY",
+	TypeCDS:        "CDS",
+	TypeCERT:       "CERT",
+	TypeCNAME:      "CNAME",
+	TypeDHCID:      "DHCID",
+	TypeDLV:        "DLV",
+	TypeDNAME:      "DNAME",
+	TypeDNSKEY:     "DNSKEY",
+	TypeDS:         "DS",
+	TypeEID:        "EID",
+	TypeEUI48:      "EUI48",
+	TypeEUI64:      "EUI64",
+	TypeGID:        "GID",
+	TypeGPOS:       "GPOS",
+	TypeHINFO:      "HINFO",
+	TypeHIP:        "HIP",
+	TypeIPSECKEY:   "IPSECKEY",
+	TypeISDN:       "ISDN",
+	TypeIXFR:       "IXFR",
+	TypeKEY:        "KEY",
+	TypeKX:         "KX",
+	TypeL32:        "L32",
+	TypeL64:        "L64",
+	TypeLOC:        "LOC",
+	TypeLP:         "LP",
+	TypeMAILA:      "MAILA",
+	TypeMAILB:      "MAILB",
+	TypeMB:         "MB",
+	TypeMD:         "MD",
+	TypeMF:         "MF",
+	TypeMG:         "MG",
+	TypeMINFO:      "MINFO",
+	TypeMR:         "MR",
+	TypeMX:         "MX",
+	TypeNAPTR:      "NAPTR",
+	TypeNID:        "NID",
+	TypeNIMLOC:     "NIMLOC",
+	TypeNINFO:      "NINFO",
+	TypeNS:         "NS",
+	TypeNSEC:       "NSEC",
+	TypeNSEC3:      "NSEC3",
+	TypeNSEC3PARAM: "NSEC3PARAM",
+	TypeNULL:       "NULL",
+	TypeNXT:        "NXT",
+	TypeNone:       "None",
+	TypeOPENPGPKEY: "OPENPGPKEY",
+	TypeOPT:        "OPT",
+	TypePTR:        "PTR",
+	TypePX:         "PX",
+	TypeRKEY:       "RKEY",
+	TypeRP:         "RP",
+	TypeRRSIG:      "RRSIG",
+	TypeRT:         "RT",
+	TypeReserved:   "Reserved",
+	TypeSIG:        "SIG",
+	TypeSOA:        "SOA",
+	TypeSPF:        "SPF",
+	TypeSRV:        "SRV",
+	TypeSSHFP:      "SSHFP",
+	TypeTA:         "TA",
+	TypeTALINK:     "TALINK",
+	TypeTKEY:       "TKEY",
+	TypeTLSA:       "TLSA",
+	TypeTSIG:       "TSIG",
+	TypeTXT:        "TXT",
+	TypeUID:        "UID",
+	TypeUINFO:      "UINFO",
+	TypeUNSPEC:     "UNSPEC",
+	TypeURI:        "URI",
+	TypeWKS:        "WKS",
+	TypeX25:        "X25",
+	TypeNSAPPTR:    "NSAP-PTR",
+}
+
+// Header() functions
+func (rr *A) Header() *RR_Header          { return &rr.Hdr }
+func (rr *AAAA) Header() *RR_Header       { return &rr.Hdr }
+func (rr *AFSDB) Header() *RR_Header      { return &rr.Hdr }
+func (rr *ANY) Header() *RR_Header        { return &rr.Hdr }
+func (rr *CAA) Header() *RR_Header        { return &rr.Hdr }
+func (rr *CDNSKEY) Header() *RR_Header    { return &rr.Hdr }
+func (rr *CDS) Header() *RR_Header        { return &rr.Hdr }
+func (rr *CERT) Header() *RR_Header       { return &rr.Hdr }
+func (rr *CNAME) Header() *RR_Header      { return &rr.Hdr }
+func (rr *DHCID) Header() *RR_Header      { return &rr.Hdr }
+func (rr *DLV) Header() *RR_Header        { return &rr.Hdr }
+func (rr *DNAME) Header() *RR_Header      { return &rr.Hdr }
+func (rr *DNSKEY) Header() *RR_Header     { return &rr.Hdr }
+func (rr *DS) Header() *RR_Header         { return &rr.Hdr }
+func (rr *EID) Header() *RR_Header        { return &rr.Hdr }
+func (rr *EUI48) Header() *RR_Header      { return &rr.Hdr }
+func (rr *EUI64) Header() *RR_Header      { return &rr.Hdr }
+func (rr *GID) Header() *RR_Header        { return &rr.Hdr }
+func (rr *GPOS) Header() *RR_Header       { return &rr.Hdr }
+func (rr *HINFO) Header() *RR_Header      { return &rr.Hdr }
+func (rr *HIP) Header() *RR_Header        { return &rr.Hdr }
+func (rr *IPSECKEY) Header() *RR_Header   { return &rr.Hdr }
+func (rr *KEY) Header() *RR_Header        { return &rr.Hdr }
+func (rr *KX) Header() *RR_Header         { return &rr.Hdr }
+func (rr *L32) Header() *RR_Header        { return &rr.Hdr }
+func (rr *L64) Header() *RR_Header        { return &rr.Hdr }
+func (rr *LOC) Header() *RR_Header        { return &rr.Hdr }
+func (rr *LP) Header() *RR_Header         { return &rr.Hdr }
+func (rr *MB) Header() *RR_Header         { return &rr.Hdr }
+func (rr *MD) Header() *RR_Header         { return &rr.Hdr }
+func (rr *MF) Header() *RR_Header         { return &rr.Hdr }
+func (rr *MG) Header() *RR_Header         { return &rr.Hdr }
+func (rr *MINFO) Header() *RR_Header      { return &rr.Hdr }
+func (rr *MR) Header() *RR_Header         { return &rr.Hdr }
+func (rr *MX) Header() *RR_Header         { return &rr.Hdr }
+func (rr *NAPTR) Header() *RR_Header      { return &rr.Hdr }
+func (rr *NID) Header() *RR_Header        { return &rr.Hdr }
+func (rr *NIMLOC) Header() *RR_Header     { return &rr.Hdr }
+func (rr *NINFO) Header() *RR_Header      { return &rr.Hdr }
+func (rr *NS) Header() *RR_Header         { return &rr.Hdr }
+func (rr *NSAPPTR) Header() *RR_Header    { return &rr.Hdr }
+func (rr *NSEC) Header() *RR_Header       { return &rr.Hdr }
+func (rr *NSEC3) Header() *RR_Header      { return &rr.Hdr }
+func (rr *NSEC3PARAM) Header() *RR_Header { return &rr.Hdr }
+func (rr *OPENPGPKEY) Header() *RR_Header { return &rr.Hdr }
+func (rr *OPT) Header() *RR_Header        { return &rr.Hdr }
+func (rr *PTR) Header() *RR_Header        { return &rr.Hdr }
+func (rr *PX) Header() *RR_Header         { return &rr.Hdr }
+func (rr *RFC3597) Header() *RR_Header    { return &rr.Hdr }
+func (rr *RKEY) Header() *RR_Header       { return &rr.Hdr }
+func (rr *RP) Header() *RR_Header         { return &rr.Hdr }
+func (rr *RRSIG) Header() *RR_Header      { return &rr.Hdr }
+func (rr *RT) Header() *RR_Header         { return &rr.Hdr }
+func (rr *SIG) Header() *RR_Header        { return &rr.Hdr }
+func (rr *SOA) Header() *RR_Header        { return &rr.Hdr }
+func (rr *SPF) Header() *RR_Header        { return &rr.Hdr }
+func (rr *SRV) Header() *RR_Header        { return &rr.Hdr }
+func (rr *SSHFP) Header() *RR_Header      { return &rr.Hdr }
+func (rr *TA) Header() *RR_Header         { return &rr.Hdr }
+func (rr *TALINK) Header() *RR_Header     { return &rr.Hdr }
+func (rr *TKEY) Header() *RR_Header       { return &rr.Hdr }
+func (rr *TLSA) Header() *RR_Header       { return &rr.Hdr }
+func (rr *TSIG) Header() *RR_Header       { return &rr.Hdr }
+func (rr *TXT) Header() *RR_Header        { return &rr.Hdr }
+func (rr *UID) Header() *RR_Header        { return &rr.Hdr }
+func (rr *UINFO) Header() *RR_Header      { return &rr.Hdr }
+func (rr *URI) Header() *RR_Header        { return &rr.Hdr }
+func (rr *WKS) Header() *RR_Header        { return &rr.Hdr }
+func (rr *X25) Header() *RR_Header        { return &rr.Hdr }
+
+// len() functions
+func (rr *A) len() int {
+	l := rr.Hdr.len()
+	l += net.IPv4len // A
+	return l
+}
+func (rr *AAAA) len() int {
+	l := rr.Hdr.len()
+	l += net.IPv6len // AAAA
+	return l
+}
+func (rr *AFSDB) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Subtype
+	l += len(rr.Hostname) + 1
+	return l
+}
+func (rr *ANY) len() int {
+	l := rr.Hdr.len()
+	return l
+}
+func (rr *CAA) len() int {
+	l := rr.Hdr.len()
+	l += 1 // Flag
+	l += len(rr.Tag) + 1
+	l += len(rr.Value)
+	return l
+}
+func (rr *CERT) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Type
+	l += 2 // KeyTag
+	l += 1 // Algorithm
+	l += base64.StdEncoding.DecodedLen(len(rr.Certificate))
+	return l
+}
+func (rr *CNAME) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Target) + 1
+	return l
+}
+func (rr *DHCID) len() int {
+	l := rr.Hdr.len()
+	l += base64.StdEncoding.DecodedLen(len(rr.Digest))
+	return l
+}
+func (rr *DNAME) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Target) + 1
+	return l
+}
+func (rr *DNSKEY) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Flags
+	l += 1 // Protocol
+	l += 1 // Algorithm
+	l += base64.StdEncoding.DecodedLen(len(rr.PublicKey))
+	return l
+}
+func (rr *DS) len() int {
+	l := rr.Hdr.len()
+	l += 2 // KeyTag
+	l += 1 // Algorithm
+	l += 1 // DigestType
+	l += len(rr.Digest)/2 + 1
+	return l
+}
+func (rr *EID) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Endpoint)/2 + 1
+	return l
+}
+func (rr *EUI48) len() int {
+	l := rr.Hdr.len()
+	l += 6 // Address
+	return l
+}
+func (rr *EUI64) len() int {
+	l := rr.Hdr.len()
+	l += 8 // Address
+	return l
+}
+func (rr *GID) len() int {
+	l := rr.Hdr.len()
+	l += 4 // Gid
+	return l
+}
+func (rr *GPOS) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Longitude) + 1
+	l += len(rr.Latitude) + 1
+	l += len(rr.Altitude) + 1
+	return l
+}
+func (rr *HINFO) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Cpu) + 1
+	l += len(rr.Os) + 1
+	return l
+}
+func (rr *HIP) len() int {
+	l := rr.Hdr.len()
+	l += 1 // HitLength
+	l += 1 // PublicKeyAlgorithm
+	l += 2 // PublicKeyLength
+	l += len(rr.Hit)/2 + 1
+	l += base64.StdEncoding.DecodedLen(len(rr.PublicKey))
+	for _, x := range rr.RendezvousServers {
+		l += len(x) + 1
+	}
+	return l
+}
+func (rr *KX) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += len(rr.Exchanger) + 1
+	return l
+}
+func (rr *L32) len() int {
+	l := rr.Hdr.len()
+	l += 2           // Preference
+	l += net.IPv4len // Locator32
+	return l
+}
+func (rr *L64) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += 8 // Locator64
+	return l
+}
+func (rr *LOC) len() int {
+	l := rr.Hdr.len()
+	l += 1 // Version
+	l += 1 // Size
+	l += 1 // HorizPre
+	l += 1 // VertPre
+	l += 4 // Latitude
+	l += 4 // Longitude
+	l += 4 // Altitude
+	return l
+}
+func (rr *LP) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += len(rr.Fqdn) + 1
+	return l
+}
+func (rr *MB) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Mb) + 1
+	return l
+}
+func (rr *MD) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Md) + 1
+	return l
+}
+func (rr *MF) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Mf) + 1
+	return l
+}
+func (rr *MG) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Mg) + 1
+	return l
+}
+func (rr *MINFO) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Rmail) + 1
+	l += len(rr.Email) + 1
+	return l
+}
+func (rr *MR) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Mr) + 1
+	return l
+}
+func (rr *MX) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += len(rr.Mx) + 1
+	return l
+}
+func (rr *NAPTR) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Order
+	l += 2 // Preference
+	l += len(rr.Flags) + 1
+	l += len(rr.Service) + 1
+	l += len(rr.Regexp) + 1
+	l += len(rr.Replacement) + 1
+	return l
+}
+func (rr *NID) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += 8 // NodeID
+	return l
+}
+func (rr *NIMLOC) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Locator)/2 + 1
+	return l
+}
+func (rr *NINFO) len() int {
+	l := rr.Hdr.len()
+	for _, x := range rr.ZSData {
+		l += len(x) + 1
+	}
+	return l
+}
+func (rr *NS) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Ns) + 1
+	return l
+}
+func (rr *NSAPPTR) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Ptr) + 1
+	return l
+}
+func (rr *NSEC3PARAM) len() int {
+	l := rr.Hdr.len()
+	l += 1 // Hash
+	l += 1 // Flags
+	l += 2 // Iterations
+	l += 1 // SaltLength
+	l += len(rr.Salt)/2 + 1
+	return l
+}
+func (rr *OPENPGPKEY) len() int {
+	l := rr.Hdr.len()
+	l += base64.StdEncoding.DecodedLen(len(rr.PublicKey))
+	return l
+}
+func (rr *PTR) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Ptr) + 1
+	return l
+}
+func (rr *PX) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += len(rr.Map822) + 1
+	l += len(rr.Mapx400) + 1
+	return l
+}
+func (rr *RFC3597) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Rdata)/2 + 1
+	return l
+}
+func (rr *RKEY) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Flags
+	l += 1 // Protocol
+	l += 1 // Algorithm
+	l += base64.StdEncoding.DecodedLen(len(rr.PublicKey))
+	return l
+}
+func (rr *RP) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Mbox) + 1
+	l += len(rr.Txt) + 1
+	return l
+}
+func (rr *RRSIG) len() int {
+	l := rr.Hdr.len()
+	l += 2 // TypeCovered
+	l += 1 // Algorithm
+	l += 1 // Labels
+	l += 4 // OrigTtl
+	l += 4 // Expiration
+	l += 4 // Inception
+	l += 2 // KeyTag
+	l += len(rr.SignerName) + 1
+	l += base64.StdEncoding.DecodedLen(len(rr.Signature))
+	return l
+}
+func (rr *RT) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Preference
+	l += len(rr.Host) + 1
+	return l
+}
+func (rr *SOA) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Ns) + 1
+	l += len(rr.Mbox) + 1
+	l += 4 // Serial
+	l += 4 // Refresh
+	l += 4 // Retry
+	l += 4 // Expire
+	l += 4 // Minttl
+	return l
+}
+func (rr *SPF) len() int {
+	l := rr.Hdr.len()
+	for _, x := range rr.Txt {
+		l += len(x) + 1
+	}
+	return l
+}
+func (rr *SRV) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Priority
+	l += 2 // Weight
+	l += 2 // Port
+	l += len(rr.Target) + 1
+	return l
+}
+func (rr *SSHFP) len() int {
+	l := rr.Hdr.len()
+	l += 1 // Algorithm
+	l += 1 // Type
+	l += len(rr.FingerPrint)/2 + 1
+	return l
+}
+func (rr *TA) len() int {
+	l := rr.Hdr.len()
+	l += 2 // KeyTag
+	l += 1 // Algorithm
+	l += 1 // DigestType
+	l += len(rr.Digest)/2 + 1
+	return l
+}
+func (rr *TALINK) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.PreviousName) + 1
+	l += len(rr.NextName) + 1
+	return l
+}
+func (rr *TKEY) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Algorithm) + 1
+	l += 4 // Inception
+	l += 4 // Expiration
+	l += 2 // Mode
+	l += 2 // Error
+	l += 2 // KeySize
+	l += len(rr.Key) + 1
+	l += 2 // OtherLen
+	l += len(rr.OtherData) + 1
+	return l
+}
+func (rr *TLSA) len() int {
+	l := rr.Hdr.len()
+	l += 1 // Usage
+	l += 1 // Selector
+	l += 1 // MatchingType
+	l += len(rr.Certificate)/2 + 1
+	return l
+}
+func (rr *TSIG) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Algorithm) + 1
+	l += 6 // TimeSigned
+	l += 2 // Fudge
+	l += 2 // MACSize
+	l += len(rr.MAC)/2 + 1
+	l += 2 // OrigId
+	l += 2 // Error
+	l += 2 // OtherLen
+	l += len(rr.OtherData)/2 + 1
+	return l
+}
+func (rr *TXT) len() int {
+	l := rr.Hdr.len()
+	for _, x := range rr.Txt {
+		l += len(x) + 1
+	}
+	return l
+}
+func (rr *UID) len() int {
+	l := rr.Hdr.len()
+	l += 4 // Uid
+	return l
+}
+func (rr *UINFO) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.Uinfo) + 1
+	return l
+}
+func (rr *URI) len() int {
+	l := rr.Hdr.len()
+	l += 2 // Priority
+	l += 2 // Weight
+	l += len(rr.Target)
+	return l
+}
+func (rr *X25) len() int {
+	l := rr.Hdr.len()
+	l += len(rr.PSDNAddress) + 1
+	return l
+}
+
+// copy() functions
+func (rr *A) copy() RR {
+	return &A{*rr.Hdr.copyHeader(), copyIP(rr.A)}
+}
+func (rr *AAAA) copy() RR {
+	return &AAAA{*rr.Hdr.copyHeader(), copyIP(rr.AAAA)}
+}
+func (rr *AFSDB) copy() RR {
+	return &AFSDB{*rr.Hdr.copyHeader(), rr.Subtype, rr.Hostname}
+}
+func (rr *ANY) copy() RR {
+	return &ANY{*rr.Hdr.copyHeader()}
+}
+func (rr *CAA) copy() RR {
+	return &CAA{*rr.Hdr.copyHeader(), rr.Flag, rr.Tag, rr.Value}
+}
+func (rr *CERT) copy() RR {
+	return &CERT{*rr.Hdr.copyHeader(), rr.Type, rr.KeyTag, rr.Algorithm, rr.Certificate}
+}
+func (rr *CNAME) copy() RR {
+	return &CNAME{*rr.Hdr.copyHeader(), rr.Target}
+}
+func (rr *DHCID) copy() RR {
+	return &DHCID{*rr.Hdr.copyHeader(), rr.Digest}
+}
+func (rr *DNAME) copy() RR {
+	return &DNAME{*rr.Hdr.copyHeader(), rr.Target}
+}
+func (rr *DNSKEY) copy() RR {
+	return &DNSKEY{*rr.Hdr.copyHeader(), rr.Flags, rr.Protocol, rr.Algorithm, rr.PublicKey}
+}
+func (rr *DS) copy() RR {
+	return &DS{*rr.Hdr.copyHeader(), rr.KeyTag, rr.Algorithm, rr.DigestType, rr.Digest}
+}
+func (rr *EID) copy() RR {
+	return &EID{*rr.Hdr.copyHeader(), rr.Endpoint}
+}
+func (rr *EUI48) copy() RR {
+	return &EUI48{*rr.Hdr.copyHeader(), rr.Address}
+}
+func (rr *EUI64) copy() RR {
+	return &EUI64{*rr.Hdr.copyHeader(), rr.Address}
+}
+func (rr *GID) copy() RR {
+	return &GID{*rr.Hdr.copyHeader(), rr.Gid}
+}
+func (rr *GPOS) copy() RR {
+	return &GPOS{*rr.Hdr.copyHeader(), rr.Longitude, rr.Latitude, rr.Altitude}
+}
+func (rr *HINFO) copy() RR {
+	return &HINFO{*rr.Hdr.copyHeader(), rr.Cpu, rr.Os}
+}
+func (rr *HIP) copy() RR {
+	RendezvousServers := make([]string, len(rr.RendezvousServers))
+	copy(RendezvousServers, rr.RendezvousServers)
+	return &HIP{*rr.Hdr.copyHeader(), rr.HitLength, rr.PublicKeyAlgorithm, rr.PublicKeyLength, rr.Hit, rr.PublicKey, RendezvousServers}
+}
+func (rr *IPSECKEY) copy() RR {
+	return &IPSECKEY{*rr.Hdr.copyHeader(), rr.Precedence, rr.GatewayType, rr.Algorithm, copyIP(rr.GatewayA), copyIP(rr.GatewayAAAA), rr.GatewayName, rr.PublicKey}
+}
+func (rr *KX) copy() RR {
+	return &KX{*rr.Hdr.copyHeader(), rr.Preference, rr.Exchanger}
+}
+func (rr *L32) copy() RR {
+	return &L32{*rr.Hdr.copyHeader(), rr.Preference, copyIP(rr.Locator32)}
+}
+func (rr *L64) copy() RR {
+	return &L64{*rr.Hdr.copyHeader(), rr.Preference, rr.Locator64}
+}
+func (rr *LOC) copy() RR {
+	return &LOC{*rr.Hdr.copyHeader(), rr.Version, rr.Size, rr.HorizPre, rr.VertPre, rr.Latitude, rr.Longitude, rr.Altitude}
+}
+func (rr *LP) copy() RR {
+	return &LP{*rr.Hdr.copyHeader(), rr.Preference, rr.Fqdn}
+}
+func (rr *MB) copy() RR {
+	return &MB{*rr.Hdr.copyHeader(), rr.Mb}
+}
+func (rr *MD) copy() RR {
+	return &MD{*rr.Hdr.copyHeader(), rr.Md}
+}
+func (rr *MF) copy() RR {
+	return &MF{*rr.Hdr.copyHeader(), rr.Mf}
+}
+func (rr *MG) copy() RR {
+	return &MG{*rr.Hdr.copyHeader(), rr.Mg}
+}
+func (rr *MINFO) copy() RR {
+	return &MINFO{*rr.Hdr.copyHeader(), rr.Rmail, rr.Email}
+}
+func (rr *MR) copy() RR {
+	return &MR{*rr.Hdr.copyHeader(), rr.Mr}
+}
+func (rr *MX) copy() RR {
+	return &MX{*rr.Hdr.copyHeader(), rr.Preference, rr.Mx}
+}
+func (rr *NAPTR) copy() RR {
+	return &NAPTR{*rr.Hdr.copyHeader(), rr.Order, rr.Preference, rr.Flags, rr.Service, rr.Regexp, rr.Replacement}
+}
+func (rr *NID) copy() RR {
+	return &NID{*rr.Hdr.copyHeader(), rr.Preference, rr.NodeID}
+}
+func (rr *NIMLOC) copy() RR {
+	return &NIMLOC{*rr.Hdr.copyHeader(), rr.Locator}
+}
+func (rr *NINFO) copy() RR {
+	ZSData := make([]string, len(rr.ZSData))
+	copy(ZSData, rr.ZSData)
+	return &NINFO{*rr.Hdr.copyHeader(), ZSData}
+}
+func (rr *NS) copy() RR {
+	return &NS{*rr.Hdr.copyHeader(), rr.Ns}
+}
+func (rr *NSAPPTR) copy() RR {
+	return &NSAPPTR{*rr.Hdr.copyHeader(), rr.Ptr}
+}
+func (rr *NSEC) copy() RR {
+	TypeBitMap := make([]uint16, len(rr.TypeBitMap))
+	copy(TypeBitMap, rr.TypeBitMap)
+	return &NSEC{*rr.Hdr.copyHeader(), rr.NextDomain, TypeBitMap}
+}
+func (rr *NSEC3) copy() RR {
+	TypeBitMap := make([]uint16, len(rr.TypeBitMap))
+	copy(TypeBitMap, rr.TypeBitMap)
+	return &NSEC3{*rr.Hdr.copyHeader(), rr.Hash, rr.Flags, rr.Iterations, rr.SaltLength, rr.Salt, rr.HashLength, rr.NextDomain, TypeBitMap}
+}
+func (rr *NSEC3PARAM) copy() RR {
+	return &NSEC3PARAM{*rr.Hdr.copyHeader(), rr.Hash, rr.Flags, rr.Iterations, rr.SaltLength, rr.Salt}
+}
+func (rr *OPENPGPKEY) copy() RR {
+	return &OPENPGPKEY{*rr.Hdr.copyHeader(), rr.PublicKey}
+}
+func (rr *OPT) copy() RR {
+	Option := make([]EDNS0, len(rr.Option))
+	copy(Option, rr.Option)
+	return &OPT{*rr.Hdr.copyHeader(), Option}
+}
+func (rr *PTR) copy() RR {
+	return &PTR{*rr.Hdr.copyHeader(), rr.Ptr}
+}
+func (rr *PX) copy() RR {
+	return &PX{*rr.Hdr.copyHeader(), rr.Preference, rr.Map822, rr.Mapx400}
+}
+func (rr *RFC3597) copy() RR {
+	return &RFC3597{*rr.Hdr.copyHeader(), rr.Rdata}
+}
+func (rr *RKEY) copy() RR {
+	return &RKEY{*rr.Hdr.copyHeader(), rr.Flags, rr.Protocol, rr.Algorithm, rr.PublicKey}
+}
+func (rr *RP) copy() RR {
+	return &RP{*rr.Hdr.copyHeader(), rr.Mbox, rr.Txt}
+}
+func (rr *RRSIG) copy() RR {
+	return &RRSIG{*rr.Hdr.copyHeader(), rr.TypeCovered, rr.Algorithm, rr.Labels, rr.OrigTtl, rr.Expiration, rr.Inception, rr.KeyTag, rr.SignerName, rr.Signature}
+}
+func (rr *RT) copy() RR {
+	return &RT{*rr.Hdr.copyHeader(), rr.Preference, rr.Host}
+}
+func (rr *SOA) copy() RR {
+	return &SOA{*rr.Hdr.copyHeader(), rr.Ns, rr.Mbox, rr.Serial, rr.Refresh, rr.Retry, rr.Expire, rr.Minttl}
+}
+func (rr *SPF) copy() RR {
+	Txt := make([]string, len(rr.Txt))
+	copy(Txt, rr.Txt)
+	return &SPF{*rr.Hdr.copyHeader(), Txt}
+}
+func (rr *SRV) copy() RR {
+	return &SRV{*rr.Hdr.copyHeader(), rr.Priority, rr.Weight, rr.Port, rr.Target}
+}
+func (rr *SSHFP) copy() RR {
+	return &SSHFP{*rr.Hdr.copyHeader(), rr.Algorithm, rr.Type, rr.FingerPrint}
+}
+func (rr *TA) copy() RR {
+	return &TA{*rr.Hdr.copyHeader(), rr.KeyTag, rr.Algorithm, rr.DigestType, rr.Digest}
+}
+func (rr *TALINK) copy() RR {
+	return &TALINK{*rr.Hdr.copyHeader(), rr.PreviousName, rr.NextName}
+}
+func (rr *TKEY) copy() RR {
+	return &TKEY{*rr.Hdr.copyHeader(), rr.Algorithm, rr.Inception, rr.Expiration, rr.Mode, rr.Error, rr.KeySize, rr.Key, rr.OtherLen, rr.OtherData}
+}
+func (rr *TLSA) copy() RR {
+	return &TLSA{*rr.Hdr.copyHeader(), rr.Usage, rr.Selector, rr.MatchingType, rr.Certificate}
+}
+func (rr *TSIG) copy() RR {
+	return &TSIG{*rr.Hdr.copyHeader(), rr.Algorithm, rr.TimeSigned, rr.Fudge, rr.MACSize, rr.MAC, rr.OrigId, rr.Error, rr.OtherLen, rr.OtherData}
+}
+func (rr *TXT) copy() RR {
+	Txt := make([]string, len(rr.Txt))
+	copy(Txt, rr.Txt)
+	return &TXT{*rr.Hdr.copyHeader(), Txt}
+}
+func (rr *UID) copy() RR {
+	return &UID{*rr.Hdr.copyHeader(), rr.Uid}
+}
+func (rr *UINFO) copy() RR {
+	return &UINFO{*rr.Hdr.copyHeader(), rr.Uinfo}
+}
+func (rr *URI) copy() RR {
+	return &URI{*rr.Hdr.copyHeader(), rr.Priority, rr.Weight, rr.Target}
+}
+func (rr *WKS) copy() RR {
+	BitMap := make([]uint16, len(rr.BitMap))
+	copy(BitMap, rr.BitMap)
+	return &WKS{*rr.Hdr.copyHeader(), copyIP(rr.Address), rr.Protocol, BitMap}
+}
+func (rr *X25) copy() RR {
+	return &X25{*rr.Hdr.copyHeader(), rr.PSDNAddress}
+}