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
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
package srtp
import (
"net"
"time"
"github.com/pion/logging"
"github.com/pion/rtp"
)
const defaultSessionSRTPReplayProtectionWindow = 64
// SessionSRTP implements io.ReadWriteCloser and provides a bi-directional SRTP session
// SRTP itself does not have a design like this, but it is common in most applications
// for local/remote to each have their own keying material. This provides those patterns
// instead of making everyone re-implement
type SessionSRTP struct {
session
writeStream *WriteStreamSRTP
}
// NewSessionSRTP creates a SRTP session using conn as the underlying transport.
func NewSessionSRTP(conn net.Conn, config *Config) (*SessionSRTP, error) { //nolint:dupl
if config == nil {
return nil, errNoConfig
} else if conn == nil {
return nil, errNoConn
}
loggerFactory := config.LoggerFactory
if loggerFactory == nil {
loggerFactory = logging.NewDefaultLoggerFactory()
}
localOpts := append(
[]ContextOption{},
config.LocalOptions...,
)
remoteOpts := append(
[]ContextOption{
// Default options
SRTPReplayProtection(defaultSessionSRTPReplayProtectionWindow),
},
config.RemoteOptions...,
)
s := &SessionSRTP{
session: session{
nextConn: conn,
localOptions: localOpts,
remoteOptions: remoteOpts,
readStreams: map[uint32]readStream{},
newStream: make(chan readStream),
started: make(chan interface{}),
closed: make(chan interface{}),
bufferFactory: config.BufferFactory,
log: loggerFactory.NewLogger("srtp"),
},
}
s.writeStream = &WriteStreamSRTP{s}
err := s.session.start(
config.Keys.LocalMasterKey, config.Keys.LocalMasterSalt,
config.Keys.RemoteMasterKey, config.Keys.RemoteMasterSalt,
config.Profile,
s,
)
if err != nil {
return nil, err
}
return s, nil
}
// OpenWriteStream returns the global write stream for the Session
func (s *SessionSRTP) OpenWriteStream() (*WriteStreamSRTP, error) {
return s.writeStream, nil
}
// OpenReadStream opens a read stream for the given SSRC, it can be used
// if you want a certain SSRC, but don't want to wait for AcceptStream
func (s *SessionSRTP) OpenReadStream(ssrc uint32) (*ReadStreamSRTP, error) {
r, _ := s.session.getOrCreateReadStream(ssrc, s, newReadStreamSRTP)
if readStream, ok := r.(*ReadStreamSRTP); ok {
return readStream, nil
}
return nil, errFailedTypeAssertion
}
// AcceptStream returns a stream to handle RTCP for a single SSRC
func (s *SessionSRTP) AcceptStream() (*ReadStreamSRTP, uint32, error) {
stream, ok := <-s.newStream
if !ok {
return nil, 0, errStreamAlreadyClosed
}
readStream, ok := stream.(*ReadStreamSRTP)
if !ok {
return nil, 0, errFailedTypeAssertion
}
return readStream, stream.GetSSRC(), nil
}
// Close ends the session
func (s *SessionSRTP) Close() error {
return s.session.close()
}
func (s *SessionSRTP) write(b []byte) (int, error) {
packet := &rtp.Packet{}
err := packet.Unmarshal(b)
if err != nil {
return 0, nil
}
return s.writeRTP(&packet.Header, packet.Payload)
}
func (s *SessionSRTP) writeRTP(header *rtp.Header, payload []byte) (int, error) {
if _, ok := <-s.session.started; ok {
return 0, errStartedChannelUsedIncorrectly
}
s.session.localContextMutex.Lock()
encrypted, err := s.localContext.encryptRTP(nil, header, payload)
s.session.localContextMutex.Unlock()
if err != nil {
return 0, err
}
return s.session.nextConn.Write(encrypted)
}
func (s *SessionSRTP) setWriteDeadline(t time.Time) error {
return s.session.nextConn.SetWriteDeadline(t)
}
func (s *SessionSRTP) decrypt(buf []byte) error {
h := &rtp.Header{}
if err := h.Unmarshal(buf); err != nil {
return err
}
r, isNew := s.session.getOrCreateReadStream(h.SSRC, s, newReadStreamSRTP)
if r == nil {
return nil // Session has been closed
} else if isNew {
s.session.newStream <- r // Notify AcceptStream
}
readStream, ok := r.(*ReadStreamSRTP)
if !ok {
return errFailedTypeAssertion
}
decrypted, err := s.remoteContext.decryptRTP(buf, buf, h)
if err != nil {
return err
}
_, err = readStream.write(decrypted)
if err != nil {
return err
}
return nil
}
|
