cca interface

solanaceae/ngc_ft1/cca.hpp

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <vector>
+#include <cstdint>
+
+struct CCAI {
+	public: // config
+		using SeqIDType = std::pair<uint8_t, uint16_t>; // tf_id, seq_id
+
+		static constexpr size_t IPV4_HEADER_SIZE {20};
+		static constexpr size_t IPV6_HEADER_SIZE {40}; // bru
+		static constexpr size_t UDP_HEADER_SIZE {8};
+
+		// TODO: tcp AND IPv6 will be different
+		static constexpr size_t SEGMENT_OVERHEAD {
+			4+ // ft overhead
+			46+ // tox?
+			UDP_HEADER_SIZE+
+			IPV4_HEADER_SIZE
+		};
+
+		// TODO: make configurable, set with tox ngc lossy packet size
+		//const size_t MAXIMUM_SEGMENT_DATA_SIZE {1000-4};
+		const size_t MAXIMUM_SEGMENT_DATA_SIZE {500-4};
+
+		const size_t MAXIMUM_SEGMENT_SIZE {MAXIMUM_SEGMENT_DATA_SIZE + SEGMENT_OVERHEAD}; // tox 500 - 4 from ft
+		//static_assert(maximum_segment_size == 574); // mesured in wireshark
+
+		// flow control
+		float max_byterate_allowed {10*1024*1024}; // 10MiB/s
+
+	public: // api
+		CCAI(size_t maximum_segment_data_size) : MAXIMUM_SEGMENT_DATA_SIZE(maximum_segment_data_size) {}
+
+		// return the current believed window in bytes of how much data can be inflight,
+		virtual float getCWnD(void) const = 0;
+
+		// TODO: api for how much data we should send
+		// take time since last sent into account
+		// respect max_byterate_allowed
+		virtual size_t canSend(void) const = 0;
+
+		// get the list of timed out seq_ids
+		virtual std::vector<SeqIDType> getTimeouts(void) const = 0;
+
+	public: // callbacks
+		// data size is without overhead
+		virtual void onSent(SeqIDType seq, size_t data_size) = 0;
+
+		// TODO: copy???
+		virtual void onAck(std::vector<SeqIDType> seqs) = 0;
+
+		// if discard, not resent, not inflight
+		virtual void onLoss(SeqIDType seq, bool discard) = 0;
+};
+