Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2016 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 "webrtc/modules/rtp_rtcp/source/rtcp_packet/sender_report.h"
      12             : 
      13             : #include "webrtc/base/checks.h"
      14             : #include "webrtc/base/logging.h"
      15             : #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
      16             : #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/common_header.h"
      17             : 
      18             : namespace webrtc {
      19             : namespace rtcp {
      20             : constexpr uint8_t SenderReport::kPacketType;
      21             : //    Sender report (SR) (RFC 3550).
      22             : //     0                   1                   2                   3
      23             : //     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
      24             : //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      25             : //    |V=2|P|    RC   |   PT=SR=200   |             length            |
      26             : //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      27             : //  0 |                         SSRC of sender                        |
      28             : //    +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
      29             : //  4 |              NTP timestamp, most significant word             |
      30             : //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      31             : //  8 |             NTP timestamp, least significant word             |
      32             : //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      33             : // 12 |                         RTP timestamp                         |
      34             : //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      35             : // 16 |                     sender's packet count                     |
      36             : //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      37             : // 20 |                      sender's octet count                     |
      38             : // 24 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
      39             : 
      40           0 : SenderReport::SenderReport()
      41             :     : sender_ssrc_(0),
      42             :       rtp_timestamp_(0),
      43             :       sender_packet_count_(0),
      44           0 :       sender_octet_count_(0) {}
      45             : 
      46           0 : bool SenderReport::Parse(const CommonHeader& packet) {
      47           0 :   RTC_DCHECK_EQ(packet.type(), kPacketType);
      48             : 
      49           0 :   const uint8_t report_block_count = packet.count();
      50           0 :   if (packet.payload_size_bytes() <
      51           0 :       kSenderBaseLength + report_block_count * ReportBlock::kLength) {
      52           0 :     LOG(LS_WARNING) << "Packet is too small to contain all the data.";
      53           0 :     return false;
      54             :   }
      55             :   // Read SenderReport header.
      56           0 :   const uint8_t* const payload = packet.payload();
      57           0 :   sender_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[0]);
      58           0 :   uint32_t secs = ByteReader<uint32_t>::ReadBigEndian(&payload[4]);
      59           0 :   uint32_t frac = ByteReader<uint32_t>::ReadBigEndian(&payload[8]);
      60           0 :   ntp_.Set(secs, frac);
      61           0 :   rtp_timestamp_ = ByteReader<uint32_t>::ReadBigEndian(&payload[12]);
      62           0 :   sender_packet_count_ = ByteReader<uint32_t>::ReadBigEndian(&payload[16]);
      63           0 :   sender_octet_count_ = ByteReader<uint32_t>::ReadBigEndian(&payload[20]);
      64           0 :   report_blocks_.resize(report_block_count);
      65           0 :   const uint8_t* next_block = payload + kSenderBaseLength;
      66           0 :   for (ReportBlock& block : report_blocks_) {
      67           0 :     bool block_parsed = block.Parse(next_block, ReportBlock::kLength);
      68           0 :     RTC_DCHECK(block_parsed);
      69           0 :     next_block += ReportBlock::kLength;
      70             :   }
      71             :   // Double check we didn't read beyond provided buffer.
      72           0 :   RTC_DCHECK_LE(next_block - payload,
      73           0 :                 static_cast<ptrdiff_t>(packet.payload_size_bytes()));
      74           0 :   return true;
      75             : }
      76             : 
      77           0 : bool SenderReport::Create(uint8_t* packet,
      78             :                           size_t* index,
      79             :                           size_t max_length,
      80             :                           RtcpPacket::PacketReadyCallback* callback) const {
      81           0 :   while (*index + BlockLength() > max_length) {
      82           0 :     if (!OnBufferFull(packet, index, callback))
      83           0 :       return false;
      84             :   }
      85           0 :   const size_t index_end = *index + BlockLength();
      86             : 
      87           0 :   CreateHeader(report_blocks_.size(), kPacketType, HeaderLength(), packet,
      88           0 :                index);
      89             :   // Write SenderReport header.
      90           0 :   ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 0], sender_ssrc_);
      91           0 :   ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 4], ntp_.seconds());
      92           0 :   ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 8], ntp_.fractions());
      93           0 :   ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 12], rtp_timestamp_);
      94           0 :   ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 16],
      95           0 :                                        sender_packet_count_);
      96           0 :   ByteWriter<uint32_t>::WriteBigEndian(&packet[*index + 20],
      97           0 :                                        sender_octet_count_);
      98           0 :   *index += kSenderBaseLength;
      99             :   // Write report blocks.
     100           0 :   for (const ReportBlock& block : report_blocks_) {
     101           0 :     block.Create(packet + *index);
     102           0 :     *index += ReportBlock::kLength;
     103             :   }
     104             :   // Ensure bytes written match expected.
     105           0 :   RTC_DCHECK_EQ(*index, index_end);
     106           0 :   return true;
     107             : }
     108             : 
     109           0 : bool SenderReport::AddReportBlock(const ReportBlock& block) {
     110           0 :   if (report_blocks_.size() >= kMaxNumberOfReportBlocks) {
     111           0 :     LOG(LS_WARNING) << "Max report blocks reached.";
     112           0 :     return false;
     113             :   }
     114           0 :   report_blocks_.push_back(block);
     115           0 :   return true;
     116             : }
     117             : 
     118             : }  // namespace rtcp
     119             : }  // namespace webrtc