1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
// SPDX-License-Identifier: MIT
package recordlayer
import (
"github.com/pion/dtls/v3/pkg/protocol"
"golang.org/x/crypto/cryptobyte"
)
// InnerPlaintext implements DTLSInnerPlaintext
//
// https://datatracker.ietf.org/doc/html/rfc9146#name-record-layer-extensions
type InnerPlaintext struct {
Content []byte
RealType protocol.ContentType
Zeros uint
}
// Marshal encodes a DTLS InnerPlaintext to binary.
func (p *InnerPlaintext) Marshal() ([]byte, error) {
var out cryptobyte.Builder
out.AddBytes(p.Content)
out.AddUint8(uint8(p.RealType))
out.AddBytes(make([]byte, p.Zeros))
return out.Bytes()
}
// Unmarshal populates a DTLS InnerPlaintext from binary.
func (p *InnerPlaintext) Unmarshal(data []byte) error {
// Process in reverse
i := len(data) - 1
for i >= 0 {
if data[i] != 0 {
p.Zeros = uint(len(data) - 1 - i) //nolint:gosec // G115
break
}
i--
}
if i == 0 {
return errBufferTooSmall
}
p.RealType = protocol.ContentType(data[i])
p.Content = append([]byte{}, data[:i]...)
return nil
}
|
