1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "media/cast/transport/rtcp/rtcp_builder.h"
11 #include "base/logging.h"
12 #include "media/cast/transport/cast_transport_defines.h"
13 #include "media/cast/transport/pacing/paced_sender.h"
14 #include "net/base/big_endian.h"
16 static const size_t kRtcpCastLogHeaderSize = 12;
17 static const size_t kRtcpSenderFrameLogSize = 4;
24 // RFC 3550 page 44, including end null.
25 static const uint32 kCast = ('C' << 24) + ('A' << 16) + ('S' << 8) + 'T';
26 static const uint8 kSenderLogSubtype = 1;
29 RtcpBuilder::RtcpBuilder(PacedSender* const outgoing_transport)
30 : transport_(outgoing_transport),
34 RtcpBuilder::~RtcpBuilder() {}
36 void RtcpBuilder::SendRtcpFromRtpSender(
37 uint32 packet_type_flags,
38 const RtcpSenderInfo& sender_info,
39 const RtcpDlrrReportBlock& dlrr,
40 const RtcpSenderLogMessage& sender_log,
42 const std::string& c_name) {
43 if (packet_type_flags & kRtcpRr ||
44 packet_type_flags & kRtcpPli ||
45 packet_type_flags & kRtcpRrtr ||
46 packet_type_flags & kRtcpCast ||
47 packet_type_flags & kRtcpReceiverLog ||
48 packet_type_flags & kRtcpRpsi ||
49 packet_type_flags & kRtcpRemb ||
50 packet_type_flags & kRtcpNack) {
51 NOTREACHED() << "Invalid argument";
56 packet.reserve(kMaxIpPacketSize);
57 if (packet_type_flags & kRtcpSr) {
58 BuildSR(sender_info, &packet);
61 if (packet_type_flags & kRtcpBye) {
64 if (packet_type_flags & kRtcpDlrr) {
65 BuildDlrrRb(dlrr, &packet);
67 if (packet_type_flags & kRtcpSenderLog) {
68 BuildSenderLog(sender_log, &packet);
71 return; // Sanity - don't send empty packets.
73 transport_->SendRtcpPacket(packet);
76 void RtcpBuilder::BuildSR(const RtcpSenderInfo& sender_info,
77 Packet* packet) const {
79 size_t start_size = packet->size();
80 DCHECK_LT(start_size + 52, kMaxIpPacketSize) << "Not enough buffer space";
81 if (start_size + 52 > kMaxIpPacketSize) return;
83 uint16 number_of_rows = 6;
84 packet->resize(start_size + 28);
86 net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 28);
87 big_endian_writer.WriteU8(0x80);
88 big_endian_writer.WriteU8(kPacketTypeSenderReport);
89 big_endian_writer.WriteU16(number_of_rows);
90 big_endian_writer.WriteU32(ssrc_);
91 big_endian_writer.WriteU32(sender_info.ntp_seconds);
92 big_endian_writer.WriteU32(sender_info.ntp_fraction);
93 big_endian_writer.WriteU32(sender_info.rtp_timestamp);
94 big_endian_writer.WriteU32(sender_info.send_packet_count);
95 big_endian_writer.WriteU32(static_cast<uint32>(sender_info.send_octet_count));
98 void RtcpBuilder::BuildSdec(Packet* packet) const {
99 size_t start_size = packet->size();
100 DCHECK_LT(start_size + 12 + c_name_.length(), kMaxIpPacketSize)
101 << "Not enough buffer space";
102 if (start_size + 12 > kMaxIpPacketSize) return;
104 // SDES Source Description.
105 packet->resize(start_size + 10);
107 net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 10);
108 // We always need to add one SDES CNAME.
109 big_endian_writer.WriteU8(0x80 + 1);
110 big_endian_writer.WriteU8(kPacketTypeSdes);
112 // Handle SDES length later on.
113 uint32 sdes_length_position = static_cast<uint32>(start_size) + 3;
114 big_endian_writer.WriteU16(0);
115 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
116 big_endian_writer.WriteU8(1); // CNAME = 1
117 big_endian_writer.WriteU8(static_cast<uint8>(c_name_.length()));
119 size_t sdes_length = 10 + c_name_.length();
120 packet->insert(packet->end(), c_name_.c_str(),
121 c_name_.c_str() + c_name_.length());
125 // We must have a zero field even if we have an even multiple of 4 bytes.
126 if ((packet->size() % 4) == 0) {
128 packet->push_back(0);
130 while ((packet->size() % 4) != 0) {
132 packet->push_back(0);
134 sdes_length += padding;
136 // In 32-bit words minus one and we don't count the header.
137 uint8 buffer_length = static_cast<uint8>((sdes_length / 4) - 1);
138 (*packet)[sdes_length_position] = buffer_length;
141 void RtcpBuilder::BuildBye(Packet* packet) const {
142 size_t start_size = packet->size();
143 DCHECK_LT(start_size + 8, kMaxIpPacketSize) << "Not enough buffer space";
144 if (start_size + 8 > kMaxIpPacketSize) return;
146 packet->resize(start_size + 8);
148 net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 8);
149 big_endian_writer.WriteU8(0x80 + 1);
150 big_endian_writer.WriteU8(kPacketTypeBye);
151 big_endian_writer.WriteU16(1); // Length.
152 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
157 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
159 |V=2|P|reserved | PT=XR=207 | length |
160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
162 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
163 | BT=5 | reserved | block length |
164 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
165 | SSRC_1 (SSRC of first receiver) | sub-
166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
169 | delay since last RR (DLRR) |
170 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
172 void RtcpBuilder::BuildDlrrRb(const RtcpDlrrReportBlock& dlrr,
173 Packet* packet) const {
174 size_t start_size = packet->size();
175 DCHECK_LT(start_size + 24, kMaxIpPacketSize) << "Not enough buffer space";
176 if (start_size + 24 > kMaxIpPacketSize) return;
178 packet->resize(start_size + 24);
180 net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 24);
181 big_endian_writer.WriteU8(0x80);
182 big_endian_writer.WriteU8(kPacketTypeXr);
183 big_endian_writer.WriteU16(5); // Length.
184 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
185 big_endian_writer.WriteU8(5); // Add block type.
186 big_endian_writer.WriteU8(0); // Add reserved.
187 big_endian_writer.WriteU16(3); // Block length.
188 big_endian_writer.WriteU32(ssrc_); // Add the media (received RTP) SSRC.
189 big_endian_writer.WriteU32(dlrr.last_rr);
190 big_endian_writer.WriteU32(dlrr.delay_since_last_rr);
193 void RtcpBuilder::BuildSenderLog(const RtcpSenderLogMessage& sender_log_message,
194 Packet* packet) const {
196 size_t start_size = packet->size();
197 size_t remaining_space = kMaxIpPacketSize - start_size;
198 DCHECK_GE(remaining_space, kRtcpCastLogHeaderSize + kRtcpSenderFrameLogSize)
199 << "Not enough buffer space";
200 if (remaining_space < kRtcpCastLogHeaderSize + kRtcpSenderFrameLogSize)
203 size_t space_for_x_messages =
204 (remaining_space - kRtcpCastLogHeaderSize) / kRtcpSenderFrameLogSize;
205 size_t number_of_messages = std::min(space_for_x_messages,
206 sender_log_message.size());
208 size_t log_size = kRtcpCastLogHeaderSize +
209 number_of_messages * kRtcpSenderFrameLogSize;
210 packet->resize(start_size + log_size);
212 net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), log_size);
213 big_endian_writer.WriteU8(0x80 + kSenderLogSubtype);
214 big_endian_writer.WriteU8(kPacketTypeApplicationDefined);
215 big_endian_writer.WriteU16(static_cast<uint16>(2 + number_of_messages));
216 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
217 big_endian_writer.WriteU32(kCast);
219 std::list<RtcpSenderFrameLogMessage>::const_iterator it =
220 sender_log_message.begin();
221 for (; number_of_messages > 0; --number_of_messages) {
222 DCHECK(!sender_log_message.empty());
223 const RtcpSenderFrameLogMessage& message = *it;
224 big_endian_writer.WriteU8(static_cast<uint8>(message.frame_status));
225 // We send the 24 east significant bits of the RTP timestamp.
226 big_endian_writer.WriteU8(static_cast<uint8>(message.rtp_timestamp >> 16));
227 big_endian_writer.WriteU8(static_cast<uint8>(message.rtp_timestamp >> 8));
228 big_endian_writer.WriteU8(static_cast<uint8>(message.rtp_timestamp));
233 } // namespace transport