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/big_endian.h"
12 #include "base/logging.h"
13 #include "media/cast/transport/cast_transport_defines.h"
14 #include "media/cast/transport/pacing/paced_sender.h"
20 RtcpBuilder::RtcpBuilder(PacedSender* const outgoing_transport)
21 : transport_(outgoing_transport),
25 RtcpBuilder::~RtcpBuilder() {}
27 void RtcpBuilder::SendRtcpFromRtpSender(
28 uint32 packet_type_flags,
29 const RtcpSenderInfo& sender_info,
30 const RtcpDlrrReportBlock& dlrr,
32 const std::string& c_name) {
33 if (packet_type_flags & kRtcpRr ||
34 packet_type_flags & kRtcpPli ||
35 packet_type_flags & kRtcpRrtr ||
36 packet_type_flags & kRtcpCast ||
37 packet_type_flags & kRtcpReceiverLog ||
38 packet_type_flags & kRtcpRpsi ||
39 packet_type_flags & kRtcpRemb ||
40 packet_type_flags & kRtcpNack) {
41 NOTREACHED() << "Invalid argument";
45 PacketRef packet(new base::RefCountedData<Packet>);
46 packet->data.reserve(kMaxIpPacketSize);
47 if (packet_type_flags & kRtcpSr) {
48 if (!BuildSR(sender_info, &packet->data)) return;
49 if (!BuildSdec(&packet->data)) return;
51 if (packet_type_flags & kRtcpBye) {
52 if (!BuildBye(&packet->data)) return;
54 if (packet_type_flags & kRtcpDlrr) {
55 if (!BuildDlrrRb(dlrr, &packet->data)) return;
57 if (packet->data.empty())
58 return; // Sanity - don't send empty packets.
60 transport_->SendRtcpPacket(ssrc_, packet);
63 bool RtcpBuilder::BuildSR(const RtcpSenderInfo& sender_info,
64 Packet* packet) const {
66 size_t start_size = packet->size();
67 if (start_size + 52 > kMaxIpPacketSize) {
68 DLOG(FATAL) << "Not enough buffer space";
72 uint16 number_of_rows = 6;
73 packet->resize(start_size + 28);
75 base::BigEndianWriter big_endian_writer(
76 reinterpret_cast<char*>(&((*packet)[start_size])), 28);
77 big_endian_writer.WriteU8(0x80);
78 big_endian_writer.WriteU8(kPacketTypeSenderReport);
79 big_endian_writer.WriteU16(number_of_rows);
80 big_endian_writer.WriteU32(ssrc_);
81 big_endian_writer.WriteU32(sender_info.ntp_seconds);
82 big_endian_writer.WriteU32(sender_info.ntp_fraction);
83 big_endian_writer.WriteU32(sender_info.rtp_timestamp);
84 big_endian_writer.WriteU32(sender_info.send_packet_count);
85 big_endian_writer.WriteU32(static_cast<uint32>(sender_info.send_octet_count));
89 bool RtcpBuilder::BuildSdec(Packet* packet) const {
90 size_t start_size = packet->size();
91 if (start_size + 12 + c_name_.length() > kMaxIpPacketSize) {
92 DLOG(FATAL) << "Not enough buffer space";
96 // SDES Source Description.
97 packet->resize(start_size + 10);
99 base::BigEndianWriter big_endian_writer(
100 reinterpret_cast<char*>(&((*packet)[start_size])), 10);
101 // We always need to add one SDES CNAME.
102 big_endian_writer.WriteU8(0x80 + 1);
103 big_endian_writer.WriteU8(kPacketTypeSdes);
105 // Handle SDES length later on.
106 uint32 sdes_length_position = static_cast<uint32>(start_size) + 3;
107 big_endian_writer.WriteU16(0);
108 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
109 big_endian_writer.WriteU8(1); // CNAME = 1
110 big_endian_writer.WriteU8(static_cast<uint8>(c_name_.length()));
112 size_t sdes_length = 10 + c_name_.length();
113 packet->insert(packet->end(), c_name_.c_str(),
114 c_name_.c_str() + c_name_.length());
118 // We must have a zero field even if we have an even multiple of 4 bytes.
119 if ((packet->size() % 4) == 0) {
121 packet->push_back(0);
123 while ((packet->size() % 4) != 0) {
125 packet->push_back(0);
127 sdes_length += padding;
129 // In 32-bit words minus one and we don't count the header.
130 uint8 buffer_length = static_cast<uint8>((sdes_length / 4) - 1);
131 (*packet)[sdes_length_position] = buffer_length;
135 bool RtcpBuilder::BuildBye(Packet* packet) const {
136 size_t start_size = packet->size();
137 if (start_size + 8 > kMaxIpPacketSize) {
138 DLOG(FATAL) << "Not enough buffer space";
142 packet->resize(start_size + 8);
144 base::BigEndianWriter big_endian_writer(
145 reinterpret_cast<char*>(&((*packet)[start_size])), 8);
146 big_endian_writer.WriteU8(0x80 + 1);
147 big_endian_writer.WriteU8(kPacketTypeBye);
148 big_endian_writer.WriteU16(1); // Length.
149 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
155 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
156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
157 |V=2|P|reserved | PT=XR=207 | length |
158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
161 | BT=5 | reserved | block length |
162 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
163 | SSRC_1 (SSRC of first receiver) | sub-
164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
167 | delay since last RR (DLRR) |
168 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
170 bool RtcpBuilder::BuildDlrrRb(const RtcpDlrrReportBlock& dlrr,
171 Packet* packet) const {
172 size_t start_size = packet->size();
173 if (start_size + 24 > kMaxIpPacketSize) {
174 DLOG(FATAL) << "Not enough buffer space";
178 packet->resize(start_size + 24);
180 base::BigEndianWriter big_endian_writer(
181 reinterpret_cast<char*>(&((*packet)[start_size])), 24);
182 big_endian_writer.WriteU8(0x80);
183 big_endian_writer.WriteU8(kPacketTypeXr);
184 big_endian_writer.WriteU16(5); // Length.
185 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC.
186 big_endian_writer.WriteU8(5); // Add block type.
187 big_endian_writer.WriteU8(0); // Add reserved.
188 big_endian_writer.WriteU16(3); // Block length.
189 big_endian_writer.WriteU32(ssrc_); // Add the media (received RTP) SSRC.
190 big_endian_writer.WriteU32(dlrr.last_rr);
191 big_endian_writer.WriteU32(dlrr.delay_since_last_rr);
195 } // namespace transport