Files
libdatachannel/src/rtcpnackresponder.cpp
2021-04-13 23:03:16 +02:00

124 lines
3.9 KiB
C++

/**
* Copyright (c) 2020 Filip Klembara (in2core)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#if RTC_ENABLE_MEDIA
#include "rtcpnackresponder.hpp"
#include "impl/internals.hpp"
#include <cassert>
namespace rtc {
RtcpNackResponder::Storage::Element::Element(binary_ptr packet, uint16_t sequenceNumber, shared_ptr<Element> next)
: packet(packet), sequenceNumber(sequenceNumber), next(next) { }
unsigned RtcpNackResponder::Storage::size() { return storage.size(); }
RtcpNackResponder::Storage::Storage(unsigned _maximumSize): maximumSize(_maximumSize) {
assert(maximumSize > 0);
storage.reserve(maximumSize);
}
optional<binary_ptr> RtcpNackResponder::Storage::get(uint16_t sequenceNumber) {
auto position = storage.find(sequenceNumber);
return position != storage.end() ? std::make_optional(storage.at(sequenceNumber)->packet) : nullopt;
}
void RtcpNackResponder::Storage::store(binary_ptr packet) {
if (!packet || packet->size() < 12) {
return;
}
auto rtp = reinterpret_cast<RTP *>(packet->data());
auto sequenceNumber = rtp->seqNumber();
assert((storage.empty() && !oldest && !newest) || (!storage.empty() && oldest && newest));
if (size() == 0) {
newest = std::make_shared<Element>(packet, sequenceNumber);
oldest = newest;
} else {
auto current = std::make_shared<Element>(packet, sequenceNumber);
newest->next = current;
newest = current;
}
storage.emplace(sequenceNumber, newest);
if (size() > maximumSize) {
assert(oldest);
if (oldest) {
storage.erase(oldest->sequenceNumber);
oldest = oldest->next;
}
}
}
RtcpNackResponder::RtcpNackResponder(unsigned maxStoredPacketCount)
: MediaHandlerElement(), storage(std::make_shared<Storage>(maxStoredPacketCount)) { }
ChainedIncomingControlProduct RtcpNackResponder::processIncomingControlMessage(message_ptr message) {
optional<ChainedOutgoingProduct> optPackets = ChainedOutgoingProduct(nullptr);
auto packets = make_chained_messages_product();
unsigned int i = 0;
while (i < message->size()) {
auto nack = reinterpret_cast<RTCP_NACK *>(message->data() + i);
i += nack->header.header.lengthInBytes();
// check if rtcp is nack
if (nack->header.header.payloadType() != 205 || nack->header.header.reportCount() != 1) {
continue;
}
auto fieldsCount = nack->getSeqNoCount();
std::vector<uint16_t> missingSequenceNumbers{};
for(unsigned int i = 0; i < fieldsCount; i++) {
auto field = nack->parts[i];
auto newMissingSeqenceNumbers = field.getSequenceNumbers();
missingSequenceNumbers.insert(missingSequenceNumbers.end(), newMissingSeqenceNumbers.begin(), newMissingSeqenceNumbers.end());
}
packets->reserve(packets->size() + missingSequenceNumbers.size());
for (auto sequenceNumber: missingSequenceNumbers) {
auto optPacket = storage->get(sequenceNumber);
if (optPacket.has_value()) {
auto packet = optPacket.value();
packets->push_back(packet);
}
}
}
if (!packets->empty()) {
return {message, ChainedOutgoingProduct(packets)};
} else {
return {message, nullopt};
}
}
ChainedOutgoingProduct RtcpNackResponder::processOutgoingBinaryMessage(ChainedMessagesProduct messages, message_ptr control) {
for (auto message: *messages) {
storage->store(message);
}
return {messages, control};
}
} // namespace rtc
#endif /* RTC_ENABLE_MEDIA */