seiso.moe
1package magna
2
3import (
4 "encoding/binary"
5 "fmt"
6)
7
8// Decode decodes a question from buf at the offset
9func (q *Question) Decode(buf []byte, offset int) (int, error) {
10 var err error
11 q.QName, offset, err = decodeDomain(buf, offset)
12 if err != nil {
13 return offset, fmt.Errorf("question decode: failed to decode QName: %w", err)
14 }
15
16 qtype, offset, err := getU16(buf, offset)
17 if err != nil {
18 return offset, fmt.Errorf("question decode: failed to decode QType for %s: %w", q.QName, err)
19 }
20
21 qclass, offset, err := getU16(buf, offset)
22 if err != nil {
23 return offset, fmt.Errorf("question decode: failed to decode QClass for %s: %w", q.QName, err)
24 }
25
26 q.QType = DNSType(qtype)
27 q.QClass = DNSClass(qclass)
28 return offset, nil
29}
30
31// Encode serializes a Question into bytes, using a map to handle domain name compression offsets.
32func (q *Question) Encode(bytes []byte, offsets *map[string]uint16) ([]byte, error) {
33 var err error
34 bytes, err = encodeDomain(bytes, q.QName, offsets)
35 if err != nil {
36 return nil, fmt.Errorf("question encode: failed to encode QName %s: %w", q.QName, err)
37 }
38
39 bytes = binary.BigEndian.AppendUint16(bytes, uint16(q.QType))
40 bytes = binary.BigEndian.AppendUint16(bytes, uint16(q.QClass))
41 return bytes, nil
42}