P2P - Libdatachannel/RTC Library Files

libdatachannel/include/rtc/rtcpnackresponder.hpp

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+/**
+ * Copyright (c) 2020 Filip Klembara (in2core)
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef RTC_RTCP_NACK_RESPONDER_H
+#define RTC_RTCP_NACK_RESPONDER_H
+
+#if RTC_ENABLE_MEDIA
+
+#include "mediahandler.hpp"
+#include "description.hpp"
+#include "rtp.hpp"
+
+#include <mutex>
+#include <queue>
+#include <unordered_map>
+
+namespace rtc {
+
+class RTC_CPP_EXPORT RtcpNackResponder final : public MediaHandler {
+public:
+	static const size_t DefaultMaxSize = 512;
+
+	RtcpNackResponder(size_t maxSize = DefaultMaxSize);
+
+	void media(const Description::Media &desc) override;
+	void incoming(message_vector &messages, const message_callback &send) override;
+	void outgoing(message_vector &messages, const message_callback &send) override;
+
+private:
+	message_ptr wrapInRtx(const message_ptr &original);
+
+	// RTX state populated by media() from SDP inspection
+	optional<SSRC> mRtxSsrc;
+	std::unordered_map<int, int> mRtxPayloadTypeMap; // original PT -> RTX PT
+	uint16_t mRtxSequenceNumber = 0;
+	bool mRtxEnabled = false;
+	std::mutex mMutex;
+
+	// Packet storage
+	class RTC_CPP_EXPORT Storage {
+
+		/// Packet storage element
+		struct RTC_CPP_EXPORT Element {
+			Element(message_ptr packet, uint16_t sequenceNumber, shared_ptr<Element> next = nullptr);
+			const message_ptr packet;
+			const uint16_t sequenceNumber;
+			/// Pointer to newer element
+			shared_ptr<Element> next = nullptr;
+		};
+
+	private:
+		/// Oldest packet in storage
+		shared_ptr<Element> oldest = nullptr;
+		/// Newest packet in storage
+		shared_ptr<Element> newest = nullptr;
+		/// Inner storage
+		std::unordered_map<uint16_t, shared_ptr<Element>> storage{};
+		std::mutex mutex;
+
+		/// Maximum storage size
+		const size_t maxSize;
+
+		/// Returns current size
+		size_t size();
+
+	public:
+		Storage(size_t _maxSize);
+
+		/// Returns packet with given sequence number
+		message_ptr get(uint16_t sequenceNumber);
+
+		/// Stores packet
+		/// @param packet Packet
+		void store(message_ptr packet);
+	};
+
+	const shared_ptr<Storage> mStorage;
+};
+
+} // namespace rtc
+
+#endif /* RTC_ENABLE_MEDIA */
+
+#endif /* RTC_RTCP_NACK_RESPONDER_H */