kcp-2.0.0: a pluggable congestion control system that allows you to replace the built-in algorithm by installing callbacks without modifying KCP code.

.gitignore

@@ -1,14 +1,69 @@
-*.o
+*
+!*/
+!*.*
+
 *.obj
+*.o
+*.lib
+*.ipch
+*.pch
+*.sdf
 *.exe
+*.a
+*.p
 *.dll
 *.so
-*.dylib
-*.ncb
+*.sdf
+
+.tasks
+.root
+__pycache__
+/build/*
+/example/build/*
+/gateway/build/*
 
 /.vscode/*
-/.idea/*
-/.DS_Store
-/.env
-/build/*
+/.vs/*
+/.cache/*
+/testing/*.xlsx
+/testing/*.txt
+/update.cmd
+.vs
+/visualstudio/Debug/*
+/visualstudio/Release/*
+/visualstudio/x64/*
+/visualstudio/bbnet/*
+/visualstudio/.vs/*
+/visualstudio/bbnet.vcxproj.user
+
+/x64/*
+/Debug/*
+/Release/*
+/bbnet/*
+
+*.vcxproj.user
+/update.cmd
+
+*.pcap
+*.win32
+*.linux
+*.linux2
+*.log
+
+*.pyc
+*.pyo
+*.pyd
+
+__pycache__/*
+
+/session*.md
+/skills/*
+
+/.qoder/*
+/.opencode/*
+/.claude/*
+/.iflow/*
+
+nul
+
 

README.md

@@ -22,6 +22,8 @@ KCP是一个快速可靠协议，能以比 TCP 浪费 10%-20% 的带宽的代价
 
 整个协议只有 ikcp.h, ikcp.c两个源文件，可以方便的集成到用户自己的协议栈中。也许你实现了一个P2P，或者某个基于 UDP的协议，而缺乏一套完善的ARQ可靠协议实现，那么简单的拷贝这两个文件到现有项目中，稍微编写两行代码，即可使用。
 
+**注意：KCP 目前更新到 V2，增加了可插拔的流控算法机制，可以不改协议的情况下替换流控算法，老的 v1 足够稳定，我放到了 v1 这个 branch 里。**
+
 
 # 技术特性
 

ikcp.c

@@ -272,7 +272,6 @@ ikcpcb* ikcp_create(IUINT32 conv, void *user)
 	kcp->acklist = NULL;
 	kcp->ackblock = 0;
 	kcp->ackcount = 0;
-	kcp->ackedlen = 0;
 	kcp->rx_srtt = 0;
 	kcp->rx_rttval = 0;
 	kcp->rx_rto = IKCP_RTO_DEF;
@@ -596,7 +595,6 @@ static void ikcp_parse_ack(ikcpcb *kcp, IUINT32 sn)
 		IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
 		next = p->next;
 		if (sn == seg->sn) {
-			kcp->ackedlen += seg->len;
 			if (kcp->ccops && kcp->ccops->on_pkt_acked) {
 				pkt_rtt = -1;
 				if (_itimediff(kcp->current, seg->ts) >= 0) {
@@ -623,7 +621,6 @@ static void ikcp_parse_una(ikcpcb *kcp, IUINT32 una)
 		IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
 		next = p->next;
 		if (_itimediff(una, seg->sn) > 0) {
-			kcp->ackedlen += seg->len;
 			if (kcp->ccops && kcp->ccops->on_pkt_acked) {
 				kcp->ccops->on_pkt_acked(kcp, seg->sn, seg->ts,
 						seg->len, -1, seg->xmit);
@@ -785,8 +782,6 @@ int ikcp_input(ikcpcb *kcp, const char *data, long size)
 	IUINT32 maxack = 0, latest_ts = 0;
 	int flag = 0;
 
-	kcp->ackedlen = 0;
-
 	if (ikcp_canlog(kcp, IKCP_LOG_INPUT)) {
 		ikcp_log(kcp, IKCP_LOG_INPUT, "[RI] %d bytes", (int)size);
 	}
@@ -911,8 +906,7 @@ int ikcp_input(ikcpcb *kcp, const char *data, long size)
 		acked_segs = kcp->snd_una - prev_una;
 		prior_in_flight = prev_nsnd_buf;
 		if (kcp->ccops && kcp->ccops->on_ack) {
-			kcp->ccops->on_ack(kcp, acked_segs, kcp->ackedlen, 
-					prior_in_flight);
+			kcp->ccops->on_ack(kcp, acked_segs, prior_in_flight);
 		}
 		else {
 			if (kcp->cwnd < kcp->rmt_wnd) {
@@ -981,7 +975,6 @@ void ikcp_flush(ikcpcb *kcp)
 	IUINT32 rtomin;
 	IUINT32 prior_cwnd;
 	IUINT32 eff_cwnd, cur_inflight;
-	IINT32 pacing_budget = -1;
 	struct IQUEUEHEAD *p;
 	int change = 0;
 	int lost = 0;
@@ -994,10 +987,6 @@ void ikcp_flush(ikcpcb *kcp)
 		kcp->ccops->on_tick(kcp);
 	}
 
-	if (kcp->ccops && kcp->ccops->pacing_rate) {
-		pacing_budget = (IINT32)kcp->ccops->pacing_rate(kcp);
-	}
-
 	prior_cwnd = kcp->cwnd;
 
 	seg.conv = kcp->conv;
@@ -1095,6 +1084,10 @@ void ikcp_flush(ikcpcb *kcp)
 		newseg->rto = kcp->rx_rto;
 		newseg->fastack = 0;
 		newseg->xmit = 0;
+
+		if (kcp->ccops && kcp->ccops->on_pkt_sent) {
+			kcp->ccops->on_pkt_sent(kcp, newseg->sn, current, newseg->len, kcp->nsnd_buf - 1);
+		}
 	}
 
 	// check on_app_limited
@@ -1154,15 +1147,6 @@ void ikcp_flush(ikcpcb *kcp)
 			segment->wnd = seg.wnd;
 			segment->una = kcp->rcv_nxt;
 
-			if (pacing_budget >= 0 && pacing_budget < (IINT32)segment->len) {
-				break;
-			}
-
-			if (kcp->ccops && kcp->ccops->on_pkt_sent) {
-				kcp->ccops->on_pkt_sent(kcp, segment->sn, current,
-						segment->len, kcp->nsnd_buf, segment->xmit);
-			}
-
 			size = (int)(ptr - buffer);
 			need = IKCP_OVERHEAD + segment->len;
 
@@ -1178,10 +1162,6 @@ void ikcp_flush(ikcpcb *kcp)
 				ptr += segment->len;
 			}
 
-			if (pacing_budget >= 0) {
-				pacing_budget -= (IINT32)segment->len;
-			}
-
 			if (segment->xmit >= kcp->dead_link) {
 				kcp->state = (IUINT32)-1;
 			}
@@ -1197,8 +1177,7 @@ void ikcp_flush(ikcpcb *kcp)
 	// update ssthresh
 	if (change) {
 		if (kcp->ccops && kcp->ccops->on_fast_retransmit) {
-			kcp->ccops->on_fast_retransmit(kcp, (IUINT32)change, 
-					kcp->nsnd_buf, prior_cwnd);
+			kcp->ccops->on_fast_retransmit(kcp, (IUINT32)change, kcp->nsnd_buf, prior_cwnd);
 		}
 		else {
 			IUINT32 inflight = kcp->snd_nxt - kcp->snd_una;
@@ -1215,7 +1194,7 @@ void ikcp_flush(ikcpcb *kcp)
 			kcp->ccops->on_timeout(kcp, prior_cwnd);
 		}
 		else {
-			kcp->ssthresh = prior_cwnd / 2;
+			kcp->ssthresh = cwnd / 2;
 			if (kcp->ssthresh < IKCP_THRESH_MIN)
 				kcp->ssthresh = IKCP_THRESH_MIN;
 			kcp->cwnd = 1;

ikcp.h

@@ -298,8 +298,7 @@ struct IKCPOPS
 	const char *name;
 	int (*init)(ikcpcb *kcp);
 	void (*release)(ikcpcb *kcp);
-	void (*on_ack)(ikcpcb *kcp, IUINT32 acked_segs, IUINT32 acked_bytes,
-			IUINT32 prior_in_flight);
+	void (*on_ack)(ikcpcb *kcp, IUINT32 acked_segs, IUINT32 prior_in_flight);
 	void (*on_fast_retransmit)(ikcpcb *kcp, IUINT32 fast_retrans,
 				IUINT32 inflight, IUINT32 prior_cwnd);
 	void (*on_timeout)(ikcpcb *kcp, IUINT32 prior_cwnd);
@@ -307,7 +306,7 @@ struct IKCPOPS
 	void (*on_app_limited)(ikcpcb *kcp, IUINT32 inflight);
 	void (*on_rtt)(ikcpcb *kcp, IINT32 rtt);
 	void (*on_pkt_sent)(ikcpcb *kcp, IUINT32 sn, IUINT32 ts,
-				IUINT32 len, IUINT32 inflight, IUINT32 xmit);
+				IUINT32 len, IUINT32 inflight);
 	void (*on_pkt_acked)(ikcpcb *kcp, IUINT32 sn, IUINT32 ts,
 				IUINT32 len, IINT32 rtt, IUINT32 xmit);
 	IUINT32 (*get_info)(ikcpcb *kcp, void *buf, IUINT32 bufsize);
@@ -338,7 +337,6 @@ struct IKCPCB
 	IUINT32 *acklist;
 	IUINT32 ackcount;
 	IUINT32 ackblock;
-	IUINT32 ackedlen;
 	void *user;
 	char *buffer;
 	int fastresend;