X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=net%2Fipv4%2Ftcp_cong.c;h=857eefc52aab900c6a52f759f04d028f0af27516;hb=fc13dcae24bfd877aeff07774c035b2b896e05ca;hp=bbf2d6624e894b927a169d92ae2be882c851b91a;hpb=e3e3679cfc1c6689e035f6d69606253b1eda63ca;p=linux-2.6

diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index bbf2d6624e..857eefc52a 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -38,7 +38,7 @@ int tcp_register_congestion_control(struct tcp_congestion_ops *ca)
 	int ret = 0;
 
 	/* all algorithms must implement ssthresh and cong_avoid ops */
-	if (!ca->ssthresh || !ca->cong_avoid || !ca->min_cwnd) {
+	if (!ca->ssthresh || !ca->cong_avoid) {
 		printk(KERN_ERR "TCP %s does not implement required ops\n",
 		       ca->name);
 		return -EINVAL;
@@ -174,6 +174,34 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
 	return err;
 }
 
+
+/*
+ * Linear increase during slow start
+ */
+void tcp_slow_start(struct tcp_sock *tp)
+{
+	if (sysctl_tcp_abc) {
+		/* RFC3465: Slow Start
+		 * TCP sender SHOULD increase cwnd by the number of
+		 * previously unacknowledged bytes ACKed by each incoming
+		 * acknowledgment, provided the increase is not more than L
+		 */
+		if (tp->bytes_acked < tp->mss_cache)
+			return;
+
+		/* We MAY increase by 2 if discovered delayed ack */
+		if (sysctl_tcp_abc > 1 && tp->bytes_acked > 2*tp->mss_cache) {
+			if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+				tp->snd_cwnd++;
+		}
+	}
+	tp->bytes_acked = 0;
+
+	if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+		tp->snd_cwnd++;
+}
+EXPORT_SYMBOL_GPL(tcp_slow_start);
+
 /*
  * TCP Reno congestion control
  * This is special case used for fallback as well.
@@ -186,24 +214,32 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 rtt, u32 in_flight,
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
-	if (in_flight < tp->snd_cwnd)
+	if (!tcp_is_cwnd_limited(sk, in_flight))
 		return;
 
-        if (tp->snd_cwnd <= tp->snd_ssthresh) {
-                /* In "safe" area, increase. */
-		if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-			tp->snd_cwnd++;
-	} else {
-                /* In dangerous area, increase slowly.
-		 * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
-		 */
-		if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
-			if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-				tp->snd_cwnd++;
-			tp->snd_cwnd_cnt = 0;
-		} else
-			tp->snd_cwnd_cnt++;
-	}
+	/* In "safe" area, increase. */
+        if (tp->snd_cwnd <= tp->snd_ssthresh)
+		tcp_slow_start(tp);
+
+ 	/* In dangerous area, increase slowly. */
+	else if (sysctl_tcp_abc) {
+ 		/* RFC3465: Appropriate Byte Count
+ 		 * increase once for each full cwnd acked
+ 		 */
+ 		if (tp->bytes_acked >= tp->snd_cwnd*tp->mss_cache) {
+ 			tp->bytes_acked -= tp->snd_cwnd*tp->mss_cache;
+ 			if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ 				tp->snd_cwnd++;
+ 		}
+ 	} else {
+ 		/* In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd */
+ 		if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+ 			if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ 				tp->snd_cwnd++;
+ 			tp->snd_cwnd_cnt = 0;
+ 		} else
+ 			tp->snd_cwnd_cnt++;
+ 	}
 }
 EXPORT_SYMBOL_GPL(tcp_reno_cong_avoid);
 
@@ -215,8 +251,8 @@ u32 tcp_reno_ssthresh(struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(tcp_reno_ssthresh);
 
-/* Lower bound on congestion window. */
-u32 tcp_reno_min_cwnd(struct sock *sk)
+/* Lower bound on congestion window with halving. */
+u32 tcp_reno_min_cwnd(const struct sock *sk)
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
 	return tp->snd_ssthresh/2;