76 lines
2.6 KiB
C++
76 lines
2.6 KiB
C++
// Copyright 2019 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "cast/streaming/sender_report_parser.h"
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#include "cast/streaming/packet_util.h"
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#include "util/osp_logging.h"
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namespace openscreen {
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namespace cast {
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SenderReportParser::SenderReportWithId::SenderReportWithId() = default;
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SenderReportParser::SenderReportWithId::~SenderReportWithId() = default;
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SenderReportParser::SenderReportParser(RtcpSession* session)
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: session_(session) {
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OSP_DCHECK(session_);
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}
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SenderReportParser::~SenderReportParser() = default;
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absl::optional<SenderReportParser::SenderReportWithId>
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SenderReportParser::Parse(absl::Span<const uint8_t> buffer) {
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absl::optional<SenderReportWithId> sender_report;
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// The data contained in |buffer| can be a "compound packet," which means that
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// it can be the concatenation of multiple RTCP packets. The loop here
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// processes each one-by-one.
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while (!buffer.empty()) {
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const auto header = RtcpCommonHeader::Parse(buffer);
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if (!header) {
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return absl::nullopt;
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}
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buffer.remove_prefix(kRtcpCommonHeaderSize);
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if (static_cast<int>(buffer.size()) < header->payload_size) {
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return absl::nullopt;
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}
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auto chunk = buffer.subspan(0, header->payload_size);
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buffer.remove_prefix(header->payload_size);
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// Only process Sender Reports with a matching SSRC.
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if (header->packet_type != RtcpPacketType::kSenderReport) {
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continue;
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}
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if (header->payload_size < kRtcpSenderReportSize) {
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return absl::nullopt;
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}
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if (ConsumeField<uint32_t>(&chunk) != session_->sender_ssrc()) {
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continue;
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}
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SenderReportWithId& report = sender_report.emplace();
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const NtpTimestamp ntp_timestamp = ConsumeField<uint64_t>(&chunk);
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report.report_id = ToStatusReportId(ntp_timestamp);
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report.reference_time =
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session_->ntp_converter().ToLocalTime(ntp_timestamp);
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report.rtp_timestamp =
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last_parsed_rtp_timestamp_.Expand(ConsumeField<uint32_t>(&chunk));
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report.send_packet_count = ConsumeField<uint32_t>(&chunk);
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report.send_octet_count = ConsumeField<uint32_t>(&chunk);
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report.report_block = RtcpReportBlock::ParseOne(
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chunk, header->with.report_count, session_->receiver_ssrc());
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}
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// At this point, the packet is known to be well-formed. Cache the
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// most-recently parsed RTP timestamp value for bit-expansion in future
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// parses.
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if (sender_report) {
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last_parsed_rtp_timestamp_ = sender_report->rtp_timestamp;
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}
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return sender_report;
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}
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} // namespace cast
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} // namespace openscreen
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