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/*
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/report_block.h"
#include "webrtc/base/checks.h"
#include "webrtc/base/logging.h"
#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
namespace webrtc {
namespace rtcp {
// From RFC 3550, RTP: A Transport Protocol for Real-Time Applications.
//
// RTCP report block (RFC 3550).
//
// 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
// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
// 0 | SSRC_1 (SSRC of first source) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 4 | fraction lost | cumulative number of packets lost |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 8 | extended highest sequence number received |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 12 | interarrival jitter |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 16 | last SR (LSR) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 20 | delay since last SR (DLSR) |
// 24 +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
ReportBlock::ReportBlock()
: source_ssrc_(0),
fraction_lost_(0),
cumulative_lost_(0),
extended_high_seq_num_(0),
jitter_(0),
last_sr_(0),
delay_since_last_sr_(0) {}
bool ReportBlock::Parse(const uint8_t* buffer, size_t length) {
RTC_DCHECK(buffer != nullptr);
if (length < ReportBlock::kLength) {
LOG(LS_ERROR) << "Report Block should be 24 bytes long";
return false;
}
source_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&buffer[0]);
fraction_lost_ = buffer[4];
cumulative_lost_ = ByteReader<uint32_t, 3>::ReadBigEndian(&buffer[5]);
extended_high_seq_num_ = ByteReader<uint32_t>::ReadBigEndian(&buffer[8]);
jitter_ = ByteReader<uint32_t>::ReadBigEndian(&buffer[12]);
last_sr_ = ByteReader<uint32_t>::ReadBigEndian(&buffer[16]);
delay_since_last_sr_ = ByteReader<uint32_t>::ReadBigEndian(&buffer[20]);
return true;
}
void ReportBlock::Create(uint8_t* buffer) const {
// Runtime check should be done while setting cumulative_lost.
RTC_DCHECK_LT(cumulative_lost(), (1u << 24)); // Have only 3 bytes for it.
ByteWriter<uint32_t>::WriteBigEndian(&buffer[0], source_ssrc());
ByteWriter<uint8_t>::WriteBigEndian(&buffer[4], fraction_lost());
ByteWriter<uint32_t, 3>::WriteBigEndian(&buffer[5], cumulative_lost());
ByteWriter<uint32_t>::WriteBigEndian(&buffer[8], extended_high_seq_num());
ByteWriter<uint32_t>::WriteBigEndian(&buffer[12], jitter());
ByteWriter<uint32_t>::WriteBigEndian(&buffer[16], last_sr());
ByteWriter<uint32_t>::WriteBigEndian(&buffer[20], delay_since_last_sr());
}
bool ReportBlock::WithCumulativeLost(uint32_t cumulative_lost) {
if (cumulative_lost >= (1u << 24)) { // Have only 3 bytes to store it.
LOG(LS_WARNING) << "Cumulative lost is too big to fit into Report Block";
return false;
}
cumulative_lost_ = cumulative_lost;
return true;
}
} // namespace rtcp
} // namespace webrtc
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