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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/net/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/net/cast_transport_defines.h" | |
14 #include "media/cast/net/pacing/paced_sender.h" | |
15 | |
16 namespace media { | |
17 namespace cast { | |
18 | |
19 RtcpBuilder::RtcpBuilder(PacedSender* const outgoing_transport) | |
20 : transport_(outgoing_transport), | |
21 ssrc_(0) { | |
22 } | |
23 | |
24 RtcpBuilder::~RtcpBuilder() {} | |
25 | |
26 void RtcpBuilder::SendRtcpFromRtpSender( | |
27 uint32 packet_type_flags, | |
28 const RtcpSenderInfo& sender_info, | |
29 const RtcpDlrrReportBlock& dlrr, | |
30 uint32 sending_ssrc, | |
31 const std::string& c_name) { | |
32 if (packet_type_flags & kRtcpRr || | |
33 packet_type_flags & kRtcpPli || | |
34 packet_type_flags & kRtcpRrtr || | |
35 packet_type_flags & kRtcpCast || | |
36 packet_type_flags & kRtcpReceiverLog || | |
37 packet_type_flags & kRtcpRpsi || | |
38 packet_type_flags & kRtcpRemb || | |
39 packet_type_flags & kRtcpNack) { | |
40 NOTREACHED() << "Invalid argument"; | |
41 } | |
42 ssrc_ = sending_ssrc; | |
43 c_name_ = c_name; | |
44 PacketRef packet(new base::RefCountedData<Packet>); | |
45 packet->data.reserve(kMaxIpPacketSize); | |
46 if (packet_type_flags & kRtcpSr) { | |
47 if (!BuildSR(sender_info, &packet->data)) return; | |
48 if (!BuildSdec(&packet->data)) return; | |
49 } | |
50 if (packet_type_flags & kRtcpBye) { | |
51 if (!BuildBye(&packet->data)) return; | |
52 } | |
53 if (packet_type_flags & kRtcpDlrr) { | |
54 if (!BuildDlrrRb(dlrr, &packet->data)) return; | |
55 } | |
56 if (packet->data.empty()) | |
57 return; // Sanity - don't send empty packets. | |
58 | |
59 transport_->SendRtcpPacket(ssrc_, packet); | |
60 } | |
61 | |
62 bool RtcpBuilder::BuildSR(const RtcpSenderInfo& sender_info, | |
63 Packet* packet) const { | |
64 // Sender report. | |
65 size_t start_size = packet->size(); | |
66 if (start_size + 52 > kMaxIpPacketSize) { | |
67 DLOG(FATAL) << "Not enough buffer space"; | |
68 return false; | |
69 } | |
70 | |
71 uint16 number_of_rows = 6; | |
72 packet->resize(start_size + 28); | |
73 | |
74 base::BigEndianWriter big_endian_writer( | |
75 reinterpret_cast<char*>(&((*packet)[start_size])), 28); | |
76 big_endian_writer.WriteU8(0x80); | |
77 big_endian_writer.WriteU8(kPacketTypeSenderReport); | |
78 big_endian_writer.WriteU16(number_of_rows); | |
79 big_endian_writer.WriteU32(ssrc_); | |
80 big_endian_writer.WriteU32(sender_info.ntp_seconds); | |
81 big_endian_writer.WriteU32(sender_info.ntp_fraction); | |
82 big_endian_writer.WriteU32(sender_info.rtp_timestamp); | |
83 big_endian_writer.WriteU32(sender_info.send_packet_count); | |
84 big_endian_writer.WriteU32(static_cast<uint32>(sender_info.send_octet_count)); | |
85 return true; | |
86 } | |
87 | |
88 bool RtcpBuilder::BuildSdec(Packet* packet) const { | |
89 size_t start_size = packet->size(); | |
90 if (start_size + 12 + c_name_.length() > kMaxIpPacketSize) { | |
91 DLOG(FATAL) << "Not enough buffer space"; | |
92 return false; | |
93 } | |
94 | |
95 // SDES Source Description. | |
96 packet->resize(start_size + 10); | |
97 | |
98 base::BigEndianWriter big_endian_writer( | |
99 reinterpret_cast<char*>(&((*packet)[start_size])), 10); | |
100 // We always need to add one SDES CNAME. | |
101 big_endian_writer.WriteU8(0x80 + 1); | |
102 big_endian_writer.WriteU8(kPacketTypeSdes); | |
103 | |
104 // Handle SDES length later on. | |
105 uint32 sdes_length_position = static_cast<uint32>(start_size) + 3; | |
106 big_endian_writer.WriteU16(0); | |
107 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC. | |
108 big_endian_writer.WriteU8(1); // CNAME = 1 | |
109 big_endian_writer.WriteU8(static_cast<uint8>(c_name_.length())); | |
110 | |
111 size_t sdes_length = 10 + c_name_.length(); | |
112 packet->insert(packet->end(), c_name_.c_str(), | |
113 c_name_.c_str() + c_name_.length()); | |
114 | |
115 size_t padding = 0; | |
116 | |
117 // We must have a zero field even if we have an even multiple of 4 bytes. | |
118 if ((packet->size() % 4) == 0) { | |
119 padding++; | |
120 packet->push_back(0); | |
121 } | |
122 while ((packet->size() % 4) != 0) { | |
123 padding++; | |
124 packet->push_back(0); | |
125 } | |
126 sdes_length += padding; | |
127 | |
128 // In 32-bit words minus one and we don't count the header. | |
129 uint8 buffer_length = static_cast<uint8>((sdes_length / 4) - 1); | |
130 (*packet)[sdes_length_position] = buffer_length; | |
131 return true; | |
132 } | |
133 | |
134 bool RtcpBuilder::BuildBye(Packet* packet) const { | |
135 size_t start_size = packet->size(); | |
136 if (start_size + 8 > kMaxIpPacketSize) { | |
137 DLOG(FATAL) << "Not enough buffer space"; | |
138 return false; | |
139 } | |
140 | |
141 packet->resize(start_size + 8); | |
142 | |
143 base::BigEndianWriter big_endian_writer( | |
144 reinterpret_cast<char*>(&((*packet)[start_size])), 8); | |
145 big_endian_writer.WriteU8(0x80 + 1); | |
146 big_endian_writer.WriteU8(kPacketTypeBye); | |
147 big_endian_writer.WriteU16(1); // Length. | |
148 big_endian_writer.WriteU32(ssrc_); // Add our own SSRC. | |
149 return true; | |
150 } | |
151 | |
152 /* | |
153 0 1 2 3 | |
154 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 | |
155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
156 |V=2|P|reserved | PT=XR=207 | length | | |
157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
158 | SSRC | | |
159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
160 | BT=5 | reserved | block length | | |
161 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
162 | SSRC_1 (SSRC of first receiver) | sub- | |
163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block | |
164 | last RR (LRR) | 1 | |
165 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
166 | delay since last RR (DLRR) | | |
167 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
168 */ | |
169 bool RtcpBuilder::BuildDlrrRb(const RtcpDlrrReportBlock& dlrr, | |
170 Packet* packet) const { | |
171 size_t start_size = packet->size(); | |
172 if (start_size + 24 > kMaxIpPacketSize) { | |
173 DLOG(FATAL) << "Not enough buffer space"; | |
174 return false; | |
175 } | |
176 | |
177 packet->resize(start_size + 24); | |
178 | |
179 base::BigEndianWriter big_endian_writer( | |
180 reinterpret_cast<char*>(&((*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); | |
191 return true; | |
192 } | |
193 | |
194 } // namespace cast | |
195 } // namespace media | |
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