You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
75 lines
2.0 KiB
75 lines
2.0 KiB
package realm
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
// A Zone a container for records parsed from a zone file.
|
|
type Zone struct {
|
|
records []dns.RR
|
|
}
|
|
|
|
// ParseZone will attempt to parse a zone file from the provided filename and return a Zone.
|
|
// ParseZone will return an error if the file provided does not exist or could not be properly parsed.
|
|
func ParseZone(filename string) (*Zone, error) {
|
|
var zone *Zone
|
|
var err error
|
|
zone = &Zone{
|
|
records: make([]dns.RR, 0),
|
|
}
|
|
|
|
// Open the file
|
|
var file *os.File
|
|
file, err = os.Open(filename)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("could not parse zone file \"%s\": \"%s\"", filename, err)
|
|
}
|
|
defer file.Close()
|
|
|
|
// Parse the file into records
|
|
var tokens chan *dns.Token
|
|
tokens = dns.ParseZone(file, "", "")
|
|
for token := range tokens {
|
|
if token.Error != nil {
|
|
return nil, fmt.Errorf("could not parse zone file \"%s\": \"%s\"", filename, token.Error)
|
|
}
|
|
|
|
zone.records = append(zone.records, token.RR)
|
|
}
|
|
return zone, nil
|
|
}
|
|
|
|
// Lookup will find all records which we should respond with for the given name, request type, and request class.
|
|
func (zone *Zone) Lookup(name string, reqType uint16, reqClass uint16) []dns.RR {
|
|
name = dns.Fqdn(name)
|
|
var records []dns.RR
|
|
records = make([]dns.RR, 0)
|
|
for _, record := range zone.records {
|
|
var header *dns.RR_Header
|
|
header = record.Header()
|
|
|
|
// Skip this record if the name or class do not match
|
|
if header.Name != name || (header.Class != reqClass && reqClass != dns.ClassANY) {
|
|
continue
|
|
}
|
|
|
|
// Collect this record if the types match or this record is a CNAME
|
|
if reqType == dns.TypeANY || reqType == header.Rrtype {
|
|
records = append(records, record)
|
|
} else if header.Rrtype == dns.TypeCNAME {
|
|
// Append this CNAME record as a response
|
|
records = append(records, record)
|
|
|
|
// Attempt to resolve this CNAME record
|
|
var cname *dns.CNAME
|
|
cname = record.(*dns.CNAME)
|
|
var cnameRecords []dns.RR
|
|
cnameRecords = zone.Lookup(dns.Fqdn(cname.Target), reqType, reqClass)
|
|
records = append(records, cnameRecords...)
|
|
}
|
|
}
|
|
return records
|
|
}
|