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resource_record.go
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/
resource_record.go
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package dns
import (
"encoding/binary"
"fmt"
"github.com/aschepis/netfilter/ip"
)
type ResourceRecord struct {
Domain
Type uint16
Class uint16
TTL uint32
RDLength uint16
RData interface{}
}
func NewResourceRecord(packet []byte, offset int) (ResourceRecord, int) {
record := ResourceRecord{}
domain, offset, _ := NewDomain(packet, offset)
record.Domain = domain
be := binary.BigEndian
record.Type = be.Uint16(packet[offset:])
offset += 2
record.Class = be.Uint16(packet[offset:])
offset += 2
record.TTL = be.Uint32(packet[offset:])
offset += 4
record.RDLength = be.Uint16(packet[offset:])
offset += 2
offset = record.makeRData(packet, offset)
return record, offset
}
func (record *ResourceRecord) makeRData(packet []byte, offset int) int {
switch record.Type {
case 1:
be := binary.BigEndian
addr4 := ip.Addr4(be.Uint32(packet[offset:]))
record.RData = ip.NewAddr4(addr4)
case 5:
domain, _, _ := NewDomain(packet, offset)
record.RData = domain
}
return offset + int(record.RDLength)
}
func (record ResourceRecord) String() string {
return fmt.Sprintf("%v %v %v: %v", record.Domain,
record.ClassName(),
record.TypeName(),
record.RData)
}
func (record ResourceRecord) TypeName() string {
return Types[record.Type]
}
func (record ResourceRecord) ClassName() string {
return Classes[record.Class]
}