| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "media/cast/transport/rtcp/rtcp_builder.h" |
| |
| #include <algorithm> |
| #include <string> |
| #include <vector> |
| |
| #include "base/big_endian.h" |
| #include "base/logging.h" |
| #include "media/cast/transport/cast_transport_defines.h" |
| #include "media/cast/transport/pacing/paced_sender.h" |
| |
| namespace media { |
| namespace cast { |
| namespace transport { |
| |
| RtcpBuilder::RtcpBuilder(PacedSender* const outgoing_transport) |
| : transport_(outgoing_transport), |
| ssrc_(0) { |
| } |
| |
| RtcpBuilder::~RtcpBuilder() {} |
| |
| void RtcpBuilder::SendRtcpFromRtpSender( |
| uint32 packet_type_flags, |
| const RtcpSenderInfo& sender_info, |
| const RtcpDlrrReportBlock& dlrr, |
| uint32 sending_ssrc, |
| const std::string& c_name) { |
| if (packet_type_flags & kRtcpRr || |
| packet_type_flags & kRtcpPli || |
| packet_type_flags & kRtcpRrtr || |
| packet_type_flags & kRtcpCast || |
| packet_type_flags & kRtcpReceiverLog || |
| packet_type_flags & kRtcpRpsi || |
| packet_type_flags & kRtcpRemb || |
| packet_type_flags & kRtcpNack) { |
| NOTREACHED() << "Invalid argument"; |
| } |
| ssrc_ = sending_ssrc; |
| c_name_ = c_name; |
| PacketRef packet(new base::RefCountedData<Packet>); |
| packet->data.reserve(kMaxIpPacketSize); |
| if (packet_type_flags & kRtcpSr) { |
| if (!BuildSR(sender_info, &packet->data)) return; |
| if (!BuildSdec(&packet->data)) return; |
| } |
| if (packet_type_flags & kRtcpBye) { |
| if (!BuildBye(&packet->data)) return; |
| } |
| if (packet_type_flags & kRtcpDlrr) { |
| if (!BuildDlrrRb(dlrr, &packet->data)) return; |
| } |
| if (packet->data.empty()) |
| return; // Sanity - don't send empty packets. |
| |
| transport_->SendRtcpPacket(ssrc_, packet); |
| } |
| |
| bool RtcpBuilder::BuildSR(const RtcpSenderInfo& sender_info, |
| Packet* packet) const { |
| // Sender report. |
| size_t start_size = packet->size(); |
| if (start_size + 52 > kMaxIpPacketSize) { |
| DLOG(FATAL) << "Not enough buffer space"; |
| return false; |
| } |
| |
| uint16 number_of_rows = 6; |
| packet->resize(start_size + 28); |
| |
| base::BigEndianWriter big_endian_writer( |
| reinterpret_cast<char*>(&((*packet)[start_size])), 28); |
| big_endian_writer.WriteU8(0x80); |
| big_endian_writer.WriteU8(kPacketTypeSenderReport); |
| big_endian_writer.WriteU16(number_of_rows); |
| big_endian_writer.WriteU32(ssrc_); |
| big_endian_writer.WriteU32(sender_info.ntp_seconds); |
| big_endian_writer.WriteU32(sender_info.ntp_fraction); |
| big_endian_writer.WriteU32(sender_info.rtp_timestamp); |
| big_endian_writer.WriteU32(sender_info.send_packet_count); |
| big_endian_writer.WriteU32(static_cast<uint32>(sender_info.send_octet_count)); |
| return true; |
| } |
| |
| bool RtcpBuilder::BuildSdec(Packet* packet) const { |
| size_t start_size = packet->size(); |
| if (start_size + 12 + c_name_.length() > kMaxIpPacketSize) { |
| DLOG(FATAL) << "Not enough buffer space"; |
| return false; |
| } |
| |
| // SDES Source Description. |
| packet->resize(start_size + 10); |
| |
| base::BigEndianWriter big_endian_writer( |
| reinterpret_cast<char*>(&((*packet)[start_size])), 10); |
| // We always need to add one SDES CNAME. |
| big_endian_writer.WriteU8(0x80 + 1); |
| big_endian_writer.WriteU8(kPacketTypeSdes); |
| |
| // Handle SDES length later on. |
| uint32 sdes_length_position = static_cast<uint32>(start_size) + 3; |
| big_endian_writer.WriteU16(0); |
| big_endian_writer.WriteU32(ssrc_); // Add our own SSRC. |
| big_endian_writer.WriteU8(1); // CNAME = 1 |
| big_endian_writer.WriteU8(static_cast<uint8>(c_name_.length())); |
| |
| size_t sdes_length = 10 + c_name_.length(); |
| packet->insert(packet->end(), c_name_.c_str(), |
| c_name_.c_str() + c_name_.length()); |
| |
| size_t padding = 0; |
| |
| // We must have a zero field even if we have an even multiple of 4 bytes. |
| if ((packet->size() % 4) == 0) { |
| padding++; |
| packet->push_back(0); |
| } |
| while ((packet->size() % 4) != 0) { |
| padding++; |
| packet->push_back(0); |
| } |
| sdes_length += padding; |
| |
| // In 32-bit words minus one and we don't count the header. |
| uint8 buffer_length = static_cast<uint8>((sdes_length / 4) - 1); |
| (*packet)[sdes_length_position] = buffer_length; |
| return true; |
| } |
| |
| bool RtcpBuilder::BuildBye(Packet* packet) const { |
| size_t start_size = packet->size(); |
| if (start_size + 8 > kMaxIpPacketSize) { |
| DLOG(FATAL) << "Not enough buffer space"; |
| return false; |
| } |
| |
| packet->resize(start_size + 8); |
| |
| base::BigEndianWriter big_endian_writer( |
| reinterpret_cast<char*>(&((*packet)[start_size])), 8); |
| big_endian_writer.WriteU8(0x80 + 1); |
| big_endian_writer.WriteU8(kPacketTypeBye); |
| big_endian_writer.WriteU16(1); // Length. |
| big_endian_writer.WriteU32(ssrc_); // Add our own SSRC. |
| return true; |
| } |
| |
| /* |
| 0 1 2 3 |
| 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 |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |V=2|P|reserved | PT=XR=207 | length | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | SSRC | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | BT=5 | reserved | block length | |
| +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
| | SSRC_1 (SSRC of first receiver) | sub- |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block |
| | last RR (LRR) | 1 |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | delay since last RR (DLRR) | |
| +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ |
| */ |
| bool RtcpBuilder::BuildDlrrRb(const RtcpDlrrReportBlock& dlrr, |
| Packet* packet) const { |
| size_t start_size = packet->size(); |
| if (start_size + 24 > kMaxIpPacketSize) { |
| DLOG(FATAL) << "Not enough buffer space"; |
| return false; |
| } |
| |
| packet->resize(start_size + 24); |
| |
| base::BigEndianWriter big_endian_writer( |
| reinterpret_cast<char*>(&((*packet)[start_size])), 24); |
| big_endian_writer.WriteU8(0x80); |
| big_endian_writer.WriteU8(kPacketTypeXr); |
| big_endian_writer.WriteU16(5); // Length. |
| big_endian_writer.WriteU32(ssrc_); // Add our own SSRC. |
| big_endian_writer.WriteU8(5); // Add block type. |
| big_endian_writer.WriteU8(0); // Add reserved. |
| big_endian_writer.WriteU16(3); // Block length. |
| big_endian_writer.WriteU32(ssrc_); // Add the media (received RTP) SSRC. |
| big_endian_writer.WriteU32(dlrr.last_rr); |
| big_endian_writer.WriteU32(dlrr.delay_since_last_rr); |
| return true; |
| } |
| |
| } // namespace transport |
| } // namespace cast |
| } // namespace media |