implement dynamic timeout

ledbat.cpp

@@ -11,15 +11,12 @@
 #include <iostream>
 #include <limits>
 
+// https://youtu.be/0HRwNSA-JYM
+
+inline constexpr bool PLOTTING = false;
+
 LEDBAT::LEDBAT(void) {
 	_time_start_offset = clock::now();
-
-	{ // add some high delay values
-		// spec want +inf
-		//_rtt_buffer.push_back(_base_delay);
-		//_rtt_buffer.push_back(_base_delay);
-		//_rtt_buffer.push_back(_base_delay);
-	}
 }
 
 size_t LEDBAT::canSend(void) const {
@@ -27,16 +24,6 @@ size_t LEDBAT::canSend(void) const {
 		return 496u;
 	}
 
-	//const float time_since_last_sent {std::min(
-		//getTimeNow() - std::get<1>(_in_flight.back()),
-		//0.01f // 10ms max
-	//)};
-
-	//const float bps {std::min(
-		//(_cwnd / getCurrentDelay()),
-		//max_byterate_allowed
-	//)};
-
 	const int64_t cspace = _cwnd - _in_flight_bytes;
 	if (cspace < 496) {
 		return 0u;
@@ -49,24 +36,27 @@ size_t LEDBAT::canSend(void) const {
 
 	size_t space = std::ceil(std::min(cspace, fspace) / 496.f) * 496.f;
 
-	// data size, no overhead
-	//const int64_t can_send_size {std::min<int64_t>(
-		//bps * time_since_last_sent - segment_overhead,
-		//maximum_segment_size - segment_overhead
-	//)};
-	//const int64_t can_send_size {static_cast<int64_t>(bps * time_since_last_sent - segment_overhead)};
-
-	//if (can_send_size < 100) {
-		//return 0;
-	//} else {
-		//return can_send_size;
-	//}
-
 	return space;
 }
 
+std::vector<LEDBAT::SeqIDType> LEDBAT::getTimeouts(void) const {
+	std::vector<LEDBAT::SeqIDType> list;
+
+	// after 2 delays we trigger timeout
+	const auto now_adjusted = getTimeNow() - getCurrentDelay()*2.f;
+
+	for (const auto& [seq, time_stamp, size] : _in_flight) {
+		if (now_adjusted > time_stamp) {
+			list.push_back(seq);
+		}
+	}
+
+	return list;
+}
+
+
 void LEDBAT::onSent(SeqIDType seq, size_t data_size) {
-	if (true) {
+	if (false) {
 		for (const auto& it : _in_flight) {
 			assert(std::get<0>(it) != seq);
 		}
@@ -107,12 +97,7 @@ void LEDBAT::onAck(std::vector<SeqIDType> seqs) {
 		return; // not found, ignore
 	}
 
-
-	//addRTT(now - most_recent);
-
 	updateWindows();
-
-	// update cto - no? we dont handle timeouts
 }
 
 void LEDBAT::onLoss(SeqIDType seq, bool discard) {
@@ -129,7 +114,7 @@ void LEDBAT::onLoss(SeqIDType seq, bool discard) {
 
 	// at most once per rtt?
 
-	if (false) {
+	if (PLOTTING) {
 		std::cerr << "CCA: onLoss: TIME: " << getTimeNow() << "\n";
 	}
 
@@ -243,7 +228,7 @@ void LEDBAT::updateWindows(void) {
 			} // no else, we on point. very unlikely with float
 		}
 
-		if (false) { // plotting
+		if (PLOTTING) { // plotting
 			std::cerr << std::fixed << "CCA: onAck: TIME: " << now << " cwnd: " << _cwnd << "\n";
 			std::cerr << std::fixed << "CCA: onAck: TIME: " << now << " fwnd: " << _fwnd << "\n";
 			std::cerr << std::fixed << "CCA: onAck: TIME: " << now << " current_delay: " << current_delay << "\n";

ledbat.hpp

@@ -29,17 +29,17 @@ struct LEDBAT {
 		static_assert(maximum_segment_size == 574); // mesured in wireshark
 
 		// ledbat++ says 60ms, we might need other values if relayed
-		const float target_delay {0.060f};
-		//const float target_delay {0.030f};
+		//const float target_delay {0.060f};
+		const float target_delay {0.030f};
 		//const float target_delay {0.120f}; // 2x if relayed?
 
 		// TODO: use a factor for multiple of rtt
-		static constexpr size_t current_delay_filter_window {16*4*2};
+		static constexpr size_t current_delay_filter_window {16*4};
 
 		//static constexpr size_t rtt_buffer_size_max {2000};
 
-		float max_byterate_allowed {10*1024*1024}; // 10MiB/s
-		//float max_byterate_allowed {2*1024*1024};
+		//float max_byterate_allowed {10*1024*1024}; // 10MiB/s
+		float max_byterate_allowed {1*1024*1024};
 
 	public:
 		LEDBAT(void);
@@ -55,6 +55,9 @@ struct LEDBAT {
 		// respect max_byterate_allowed
 		size_t canSend(void) const;
 
+		// get the list of timed out seq_ids
+		std::vector<SeqIDType> getTimeouts(void) const;
+
 	public: // callbacks
 		// data size is without overhead
 		void onSent(SeqIDType seq, size_t data_size);

ngc_ft1.cpp

@@ -11,6 +11,7 @@
 // TODO: should i really use both?
 #include <unordered_map>
 #include <map>
+#include <set>
 #include <optional>
 #include <cassert>
 #include <cstdio>
@@ -216,10 +217,12 @@ void NGC_FT1_iterate(Tox *tox, NGC_FT1* ngc_ft1_ctx, float time_delta) {
 
 	for (auto& [group_number, group] : ngc_ft1_ctx->groups) {
 		for (auto& [peer_number, peer] : group.peers) {
-			//for (auto& tf_opt : peer.send_transfers) {
+			auto timeouts = peer.cca.getTimeouts();
+			std::set<LEDBAT::SeqIDType> timeouts_set{timeouts.cbegin(), timeouts.cend()};
+
 			for (size_t idx = 0; idx < peer.send_transfers.size(); idx++) {
 				auto& tf_opt = peer.send_transfers[idx];
-				if (tf_opt) {
+				if (tf_opt.has_value()) {
 					auto& tf = tf_opt.value();
 
 					tf.time_since_activity += time_delta;
@@ -245,11 +248,13 @@ void NGC_FT1_iterate(Tox *tox, NGC_FT1* ngc_ft1_ctx, float time_delta) {
 						case State::SENDING: {
 								tf.ssb.for_each(time_delta, [&](uint16_t id, const std::vector<uint8_t>& data, float& time_since_activity) {
 									// no ack after 5 sec -> resend
-									if (time_since_activity >= ngc_ft1_ctx->options.sending_resend_without_ack_after) {
+									//if (time_since_activity >= ngc_ft1_ctx->options.sending_resend_without_ack_after) {
+									if (timeouts_set.count({idx, id})) {
 										// TODO: can fail
 										_send_pkg_FT1_DATA(tox, group_number, peer_number, idx, id, data.data(), data.size());
 										peer.cca.onLoss({idx, id}, false);
 										time_since_activity = 0.f;
+										timeouts_set.erase({idx, id});
 									}
 								});
 
@@ -261,6 +266,7 @@ void NGC_FT1_iterate(Tox *tox, NGC_FT1* ngc_ft1_ctx, float time_delta) {
 									// clean up cca
 									tf.ssb.for_each(time_delta, [&](uint16_t id, const std::vector<uint8_t>& data, float& time_since_activity) {
 										peer.cca.onLoss({idx, id}, true);
+										timeouts_set.erase({idx, id});
 									});
 
 									tf_opt.reset();
@@ -322,10 +328,12 @@ void NGC_FT1_iterate(Tox *tox, NGC_FT1* ngc_ft1_ctx, float time_delta) {
 						case State::FINISHING: // we still have unacked packets
 							tf.ssb.for_each(time_delta, [&](uint16_t id, const std::vector<uint8_t>& data, float& time_since_activity) {
 								// no ack after 5 sec -> resend
-								if (time_since_activity >= ngc_ft1_ctx->options.sending_resend_without_ack_after) {
+								//if (time_since_activity >= ngc_ft1_ctx->options.sending_resend_without_ack_after) {
+								if (timeouts_set.count({idx, id})) {
 									_send_pkg_FT1_DATA(tox, group_number, peer_number, idx, id, data.data(), data.size());
 									peer.cca.onLoss({idx, id}, false);
 									time_since_activity = 0.f;
+									timeouts_set.erase({idx, id});
 								}
 							});
 							if (tf.time_since_activity >= ngc_ft1_ctx->options.sending_give_up_after) {
@@ -336,6 +344,7 @@ void NGC_FT1_iterate(Tox *tox, NGC_FT1* ngc_ft1_ctx, float time_delta) {
 								// clean up cca
 								tf.ssb.for_each(time_delta, [&](uint16_t id, const std::vector<uint8_t>& data, float& time_since_activity) {
 									peer.cca.onLoss({idx, id}, true);
+									timeouts_set.erase({idx, id});
 								});
 
 								tf_opt.reset();
@@ -880,7 +889,7 @@ static void _handle_FT1_DATA_ACK(
 	// delete if all packets acked
 	if (transfer.file_size == transfer.file_size_current && transfer.ssb.size() == 0) {
 		fprintf(stderr, "FT: %d done\n", transfer_id);
-		peer.send_transfers[transfer_id] = std::nullopt;
+		peer.send_transfers[transfer_id].reset();
 	}
 }
 

ngc_ft1.h

@@ -22,10 +22,8 @@ struct NGC_FT1_options {
 
 	float init_retry_timeout_after; // 10sec
 
-	float sending_resend_without_ack_after; // 5sec
+	//float sending_resend_without_ack_after; // 5sec
 	float sending_give_up_after; // 30sec
-
-	size_t packet_window_size; // 2
 };
 
 // uint32_t - same as tox friend ft