dea075c7a6
BUG=None Review-Url: https://codereview.webrtc.org/2941513002 Cr-Commit-Position: refs/heads/master@{#18569}
131 lines
4.3 KiB
C++
131 lines
4.3 KiB
C++
/*
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* Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/call/rtp_demuxer.h"
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#include "webrtc/base/checks.h"
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#include "webrtc/base/logging.h"
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#include "webrtc/call/rtp_packet_sink_interface.h"
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#include "webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h"
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#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
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namespace webrtc {
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namespace {
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constexpr size_t kMaxProcessedSsrcs = 1000; // Prevent memory overuse.
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template <typename Key, typename Value>
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bool MultimapAssociationExists(const std::multimap<Key, Value>& multimap,
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Key key,
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Value val) {
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auto it_range = multimap.equal_range(key);
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using Reference = typename std::multimap<Key, Value>::const_reference;
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return std::any_of(it_range.first, it_range.second,
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[val](Reference elem) { return elem.second == val; });
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}
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template <typename Key, typename Value>
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size_t RemoveFromMultimapByValue(std::multimap<Key, Value*>* multimap,
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const Value* value) {
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size_t count = 0;
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for (auto it = multimap->begin(); it != multimap->end();) {
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if (it->second == value) {
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it = multimap->erase(it);
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++count;
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} else {
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++it;
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}
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}
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return count;
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}
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} // namespace
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RtpDemuxer::RtpDemuxer() {}
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RtpDemuxer::~RtpDemuxer() {
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RTC_DCHECK(sinks_.empty());
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}
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void RtpDemuxer::AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink) {
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RecordSsrcToSinkAssociation(ssrc, sink);
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}
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void RtpDemuxer::AddSink(const std::string& rsid,
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RtpPacketSinkInterface* sink) {
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RTC_DCHECK(StreamId::IsLegalName(rsid));
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RTC_DCHECK(sink);
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RTC_DCHECK(!MultimapAssociationExists(rsid_sinks_, rsid, sink));
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rsid_sinks_.emplace(rsid, sink);
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// This RSID might now map to an SSRC which we saw earlier.
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processed_ssrcs_.clear();
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}
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bool RtpDemuxer::RemoveSink(const RtpPacketSinkInterface* sink) {
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RTC_DCHECK(sink);
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return (RemoveFromMultimapByValue(&sinks_, sink) +
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RemoveFromMultimapByValue(&rsid_sinks_, sink)) > 0;
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}
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void RtpDemuxer::RecordSsrcToSinkAssociation(uint32_t ssrc,
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RtpPacketSinkInterface* sink) {
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RTC_DCHECK(sink);
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// The association might already have been set by a different
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// configuration source.
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if (!MultimapAssociationExists(sinks_, ssrc, sink)) {
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sinks_.emplace(ssrc, sink);
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}
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}
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bool RtpDemuxer::OnRtpPacket(const RtpPacketReceived& packet) {
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FindSsrcAssociations(packet);
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auto it_range = sinks_.equal_range(packet.Ssrc());
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for (auto it = it_range.first; it != it_range.second; ++it) {
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it->second->OnRtpPacket(packet);
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}
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return it_range.first != it_range.second;
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}
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void RtpDemuxer::FindSsrcAssociations(const RtpPacketReceived& packet) {
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// Avoid expensive string comparisons for RSID by looking the sinks up only
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// by SSRC whenever possible.
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if (processed_ssrcs_.find(packet.Ssrc()) != processed_ssrcs_.cend()) {
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return;
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}
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// RSID-based associations:
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std::string rsid;
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if (packet.GetExtension<RtpStreamId>(&rsid)) {
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// All streams associated with this RSID need to be marked as associated
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// with this SSRC (if they aren't already).
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auto it_range = rsid_sinks_.equal_range(rsid);
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for (auto it = it_range.first; it != it_range.second; ++it) {
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RecordSsrcToSinkAssociation(packet.Ssrc(), it->second);
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}
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// To prevent memory-overuse attacks, forget this RSID. Future packets
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// with this RSID, but a different SSRC, will not spawn new associations.
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rsid_sinks_.erase(it_range.first, it_range.second);
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}
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if (processed_ssrcs_.size() < kMaxProcessedSsrcs) { // Prevent memory overuse
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processed_ssrcs_.insert(packet.Ssrc()); // Avoid re-examining in-depth.
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} else if (!logged_max_processed_ssrcs_exceeded_) {
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LOG(LS_WARNING) << "More than " << kMaxProcessedSsrcs
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<< " different SSRCs seen.";
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logged_max_processed_ssrcs_exceeded_ = true;
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}
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}
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} // namespace webrtc
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