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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. | |
4 | |
5 #include "media/cast/transport/rtcp/rtcp_builder.h" | |
6 | |
7 #include <algorithm> | |
8 #include <string> | |
9 #include <vector> | |
10 | |
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" | |
15 | |
16 namespace media { | |
17 namespace cast { | |
18 namespace transport { | |
19 | |
20 RtcpBuilder::RtcpBuilder(PacedSender* const outgoing_transport) | |
21 : transport_(outgoing_transport), | |
22 ssrc_(0) { | |
23 } | |
24 | |
25 RtcpBuilder::~RtcpBuilder() {} | |
26 | |
27 void RtcpBuilder::SendRtcpFromRtpSender( | |
28 uint32 packet_type_flags, | |
29 const RtcpSenderInfo& sender_info, | |
30 const RtcpDlrrReportBlock& dlrr, | |
31 uint32 sending_ssrc, | |
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"; | |
42 } | |
43 ssrc_ = sending_ssrc; | |
44 c_name_ = c_name; | |
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; | |
50 } | |
51 if (packet_type_flags & kRtcpBye) { | |
52 if (!BuildBye(&packet->data)) return; | |
53 } | |
54 if (packet_type_flags & kRtcpDlrr) { | |
55 if (!BuildDlrrRb(dlrr, &packet->data)) return; | |
56 } | |
57 if (packet->data.empty()) | |
58 return; // Sanity - don't send empty packets. | |
59 | |
60 transport_->SendRtcpPacket(ssrc_, packet); | |
61 } | |
62 | |
63 bool RtcpBuilder::BuildSR(const RtcpSenderInfo& sender_info, | |
64 Packet* packet) const { | |
65 // Sender report. | |
66 size_t start_size = packet->size(); | |
67 if (start_size + 52 > kMaxIpPacketSize) { | |
68 DLOG(FATAL) << "Not enough buffer space"; | |
69 return false; | |
70 } | |
71 | |
72 uint16 number_of_rows = 6; | |
73 packet->resize(start_size + 28); | |
74 | |
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)); | |
86 return true; | |
87 } | |
88 | |
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"; | |
93 return false; | |
94 } | |
95 | |
96 // SDES Source Description. | |
97 packet->resize(start_size + 10); | |
98 | |
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); | |
104 | |
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())); | |
111 | |
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()); | |
115 | |
116 size_t padding = 0; | |
117 | |
118 // We must have a zero field even if we have an even multiple of 4 bytes. | |
119 if ((packet->size() % 4) == 0) { | |
120 padding++; | |
121 packet->push_back(0); | |
122 } | |
123 while ((packet->size() % 4) != 0) { | |
124 padding++; | |
125 packet->push_back(0); | |
126 } | |
127 sdes_length += padding; | |
128 | |
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; | |
132 return true; | |
133 } | |
134 | |
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"; | |
139 return false; | |
140 } | |
141 | |
142 packet->resize(start_size + 8); | |
143 | |
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. | |
150 return true; | |
151 } | |
152 | |
153 /* | |
154 0 1 2 3 | |
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
159 | SSRC | | |
160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
161 | BT=5 | reserved | block length | | |
162 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
163 | SSRC_1 (SSRC of first receiver) | sub- | |
164 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block | |
165 | last RR (LRR) | 1 | |
166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
167 | delay since last RR (DLRR) | | |
168 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
169 */ | |
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"; | |
175 return false; | |
176 } | |
177 | |
178 packet->resize(start_size + 24); | |
179 | |
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); | |
192 return true; | |
193 } | |
194 | |
195 } // namespace transport | |
196 } // namespace cast | |
197 } // namespace media | |
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