dlrr.cc (3717B)
1 /* 2 * Copyright (c) 2015 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "modules/rtp_rtcp/source/rtcp_packet/dlrr.h" 12 13 #include <cstddef> 14 #include <cstdint> 15 16 #include "modules/rtp_rtcp/source/byte_io.h" 17 #include "rtc_base/checks.h" 18 #include "rtc_base/logging.h" 19 #include "rtc_base/numerics/safe_conversions.h" 20 21 namespace webrtc { 22 namespace rtcp { 23 // DLRR Report Block (RFC 3611). 24 // 25 // 0 1 2 3 26 // 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 27 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 28 // | BT=5 | reserved | block length | 29 // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ 30 // | SSRC_1 (SSRC of first receiver) | sub- 31 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block 32 // | last RR (LRR) | 1 33 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 34 // | delay since last RR (DLRR) | 35 // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ 36 // | SSRC_2 (SSRC of second receiver) | sub- 37 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block 38 // : ... : 2 39 40 Dlrr::Dlrr() = default; 41 42 Dlrr::Dlrr(const Dlrr& other) = default; 43 44 Dlrr::~Dlrr() = default; 45 46 bool Dlrr::Parse(const uint8_t* buffer, uint16_t block_length_32bits) { 47 RTC_DCHECK(buffer[0] == kBlockType); 48 // kReserved = buffer[1]; 49 RTC_DCHECK_EQ(block_length_32bits, 50 ByteReader<uint16_t>::ReadBigEndian(&buffer[2])); 51 if (block_length_32bits % 3 != 0) { 52 RTC_LOG(LS_WARNING) << "Invalid size for dlrr block."; 53 return false; 54 } 55 56 size_t blocks_count = block_length_32bits / 3; 57 const uint8_t* read_at = buffer + kBlockHeaderLength; 58 sub_blocks_.resize(blocks_count); 59 for (ReceiveTimeInfo& sub_block : sub_blocks_) { 60 sub_block.ssrc = ByteReader<uint32_t>::ReadBigEndian(&read_at[0]); 61 sub_block.last_rr = ByteReader<uint32_t>::ReadBigEndian(&read_at[4]); 62 sub_block.delay_since_last_rr = 63 ByteReader<uint32_t>::ReadBigEndian(&read_at[8]); 64 read_at += kSubBlockLength; 65 } 66 return true; 67 } 68 69 size_t Dlrr::BlockLength() const { 70 if (sub_blocks_.empty()) 71 return 0; 72 return kBlockHeaderLength + kSubBlockLength * sub_blocks_.size(); 73 } 74 75 void Dlrr::Create(uint8_t* buffer) const { 76 if (sub_blocks_.empty()) // No subblocks, no need to write header either. 77 return; 78 // Create block header. 79 const uint8_t kReserved = 0; 80 buffer[0] = kBlockType; 81 buffer[1] = kReserved; 82 ByteWriter<uint16_t>::WriteBigEndian( 83 &buffer[2], dchecked_cast<uint16_t>(3 * sub_blocks_.size())); 84 // Create sub blocks. 85 uint8_t* write_at = buffer + kBlockHeaderLength; 86 for (const ReceiveTimeInfo& sub_block : sub_blocks_) { 87 ByteWriter<uint32_t>::WriteBigEndian(&write_at[0], sub_block.ssrc); 88 ByteWriter<uint32_t>::WriteBigEndian(&write_at[4], sub_block.last_rr); 89 ByteWriter<uint32_t>::WriteBigEndian(&write_at[8], 90 sub_block.delay_since_last_rr); 91 write_at += kSubBlockLength; 92 } 93 RTC_DCHECK_EQ(buffer + BlockLength(), write_at); 94 } 95 96 } // namespace rtcp 97 } // namespace webrtc