summaryrefslogtreecommitdiffstats
path: root/third_party/libwebrtc/pc/sctp_utils.cc
blob: 60ffdc791945febbe793253616f6e0cc33d93f23 (plain)
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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 *  Copyright 2013 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "pc/sctp_utils.h"

#include <stddef.h>

#include <cstdint>

#include "absl/types/optional.h"
#include "api/priority.h"
#include "rtc_base/byte_buffer.h"
#include "rtc_base/copy_on_write_buffer.h"
#include "rtc_base/logging.h"

namespace webrtc {

// Format defined at
// http://tools.ietf.org/html/draft-ietf-rtcweb-data-protocol-01#section

static const uint8_t DATA_CHANNEL_OPEN_MESSAGE_TYPE = 0x03;
static const uint8_t DATA_CHANNEL_OPEN_ACK_MESSAGE_TYPE = 0x02;

enum DataChannelOpenMessageChannelType {
  DCOMCT_ORDERED_RELIABLE = 0x00,
  DCOMCT_ORDERED_PARTIAL_RTXS = 0x01,
  DCOMCT_ORDERED_PARTIAL_TIME = 0x02,
  DCOMCT_UNORDERED_RELIABLE = 0x80,
  DCOMCT_UNORDERED_PARTIAL_RTXS = 0x81,
  DCOMCT_UNORDERED_PARTIAL_TIME = 0x82,
};

// Values of priority in the DC open protocol message.
// These are compared against an integer, so are enum, not enum class.
enum DataChannelPriority {
  DCO_PRIORITY_VERY_LOW = 128,
  DCO_PRIORITY_LOW = 256,
  DCO_PRIORITY_MEDIUM = 512,
  DCO_PRIORITY_HIGH = 1024,
};

bool IsOpenMessage(const rtc::CopyOnWriteBuffer& payload) {
  // Format defined at
  // https://www.rfc-editor.org/rfc/rfc8832#section-5.1
  if (payload.size() < 1) {
    RTC_DLOG(LS_WARNING) << "Could not read OPEN message type.";
    return false;
  }

  uint8_t message_type = payload[0];
  return message_type == DATA_CHANNEL_OPEN_MESSAGE_TYPE;
}

bool ParseDataChannelOpenMessage(const rtc::CopyOnWriteBuffer& payload,
                                 std::string* label,
                                 DataChannelInit* config) {
  // Format defined at
  // http://tools.ietf.org/html/draft-jesup-rtcweb-data-protocol-04

  rtc::ByteBufferReader buffer(payload);
  uint8_t message_type;
  if (!buffer.ReadUInt8(&message_type)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message type.";
    return false;
  }
  if (message_type != DATA_CHANNEL_OPEN_MESSAGE_TYPE) {
    RTC_LOG(LS_WARNING) << "Data Channel OPEN message of unexpected type: "
                        << message_type;
    return false;
  }

  uint8_t channel_type;
  if (!buffer.ReadUInt8(&channel_type)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message channel type.";
    return false;
  }

  uint16_t priority;
  if (!buffer.ReadUInt16(&priority)) {
    RTC_LOG(LS_WARNING)
        << "Could not read OPEN message reliabilility prioirty.";
    return false;
  }
  // Parse priority as defined in
  // https://w3c.github.io/webrtc-priority/#rtcdatachannel-processing-steps
  if (priority <= DCO_PRIORITY_VERY_LOW) {
    config->priority = Priority::kVeryLow;
  } else if (priority <= DCO_PRIORITY_LOW) {
    config->priority = Priority::kLow;
  } else if (priority <= DCO_PRIORITY_MEDIUM) {
    config->priority = Priority::kMedium;
  } else {
    config->priority = Priority::kHigh;
  }

  uint32_t reliability_param;
  if (!buffer.ReadUInt32(&reliability_param)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message reliabilility param.";
    return false;
  }
  uint16_t label_length;
  if (!buffer.ReadUInt16(&label_length)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message label length.";
    return false;
  }
  uint16_t protocol_length;
  if (!buffer.ReadUInt16(&protocol_length)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message protocol length.";
    return false;
  }
  if (!buffer.ReadString(label, (size_t)label_length)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message label";
    return false;
  }
  if (!buffer.ReadString(&config->protocol, protocol_length)) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN message protocol.";
    return false;
  }

  config->ordered = true;
  switch (channel_type) {
    case DCOMCT_UNORDERED_RELIABLE:
    case DCOMCT_UNORDERED_PARTIAL_RTXS:
    case DCOMCT_UNORDERED_PARTIAL_TIME:
      config->ordered = false;
  }

  config->maxRetransmits = absl::nullopt;
  config->maxRetransmitTime = absl::nullopt;
  switch (channel_type) {
    case DCOMCT_ORDERED_PARTIAL_RTXS:
    case DCOMCT_UNORDERED_PARTIAL_RTXS:
      config->maxRetransmits = reliability_param;
      break;
    case DCOMCT_ORDERED_PARTIAL_TIME:
    case DCOMCT_UNORDERED_PARTIAL_TIME:
      config->maxRetransmitTime = reliability_param;
      break;
  }
  return true;
}

bool ParseDataChannelOpenAckMessage(const rtc::CopyOnWriteBuffer& payload) {
  if (payload.size() < 1) {
    RTC_LOG(LS_WARNING) << "Could not read OPEN_ACK message type.";
    return false;
  }

  uint8_t message_type = payload[0];
  if (message_type != DATA_CHANNEL_OPEN_ACK_MESSAGE_TYPE) {
    RTC_LOG(LS_WARNING) << "Data Channel OPEN_ACK message of unexpected type: "
                        << message_type;
    return false;
  }
  return true;
}

bool WriteDataChannelOpenMessage(const std::string& label,
                                 const DataChannelInit& config,
                                 rtc::CopyOnWriteBuffer* payload) {
  return WriteDataChannelOpenMessage(label, config.protocol, config.priority,
                                     config.ordered, config.maxRetransmits,
                                     config.maxRetransmitTime, payload);
}

bool WriteDataChannelOpenMessage(const std::string& label,
                                 const std::string& protocol,
                                 absl::optional<Priority> opt_priority,
                                 bool ordered,
                                 absl::optional<int> max_retransmits,
                                 absl::optional<int> max_retransmit_time,
                                 rtc::CopyOnWriteBuffer* payload) {
  // Format defined at
  // http://tools.ietf.org/html/draft-ietf-rtcweb-data-protocol-09#section-5.1
  uint8_t channel_type = 0;
  uint32_t reliability_param = 0;
  uint16_t priority = 0;
  // Set priority according to
  // https://tools.ietf.org/html/draft-ietf-rtcweb-data-channel-12#section-6.4
  if (opt_priority) {
    switch (*opt_priority) {
      case Priority::kVeryLow:
        priority = DCO_PRIORITY_VERY_LOW;
        break;
      case Priority::kLow:
        priority = DCO_PRIORITY_LOW;
        break;
      case Priority::kMedium:
        priority = DCO_PRIORITY_MEDIUM;
        break;
      case Priority::kHigh:
        priority = DCO_PRIORITY_HIGH;
        break;
    }
  }
  if (ordered) {
    if (max_retransmits) {
      channel_type = DCOMCT_ORDERED_PARTIAL_RTXS;
      reliability_param = *max_retransmits;
    } else if (max_retransmit_time) {
      channel_type = DCOMCT_ORDERED_PARTIAL_TIME;
      reliability_param = *max_retransmit_time;
    } else {
      channel_type = DCOMCT_ORDERED_RELIABLE;
    }
  } else {
    if (max_retransmits) {
      channel_type = DCOMCT_UNORDERED_PARTIAL_RTXS;
      reliability_param = *max_retransmits;
    } else if (max_retransmit_time) {
      channel_type = DCOMCT_UNORDERED_PARTIAL_TIME;
      reliability_param = *max_retransmit_time;
    } else {
      channel_type = DCOMCT_UNORDERED_RELIABLE;
    }
  }

  rtc::ByteBufferWriter buffer(NULL, 20 + label.length() + protocol.length());
  // TODO(tommi): Add error handling and check resulting length.
  buffer.WriteUInt8(DATA_CHANNEL_OPEN_MESSAGE_TYPE);
  buffer.WriteUInt8(channel_type);
  buffer.WriteUInt16(priority);
  buffer.WriteUInt32(reliability_param);
  buffer.WriteUInt16(static_cast<uint16_t>(label.length()));
  buffer.WriteUInt16(static_cast<uint16_t>(protocol.length()));
  buffer.WriteString(label);
  buffer.WriteString(protocol);
  payload->SetData(buffer.Data(), buffer.Length());
  return true;
}

void WriteDataChannelOpenAckMessage(rtc::CopyOnWriteBuffer* payload) {
  uint8_t data = DATA_CHANNEL_OPEN_ACK_MESSAGE_TYPE;
  payload->SetData(&data, sizeof(data));
}

}  // namespace webrtc