1 files changed, 68 insertions, 0 deletions
diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c
new file mode 100644
index 00000000000..70e108e15c7
--- /dev/null
+++ b/net/ipv4/tcp_scalable.c
@@ -0,0 +1,68 @@
+/* Tom Kelly's Scalable TCP
+ *
+ * See htt://www-lce.eng.cam.ac.uk/~ctk21/scalable/
+ *
+ * John Heffner <jheffner@sc.edu>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+/* These factors derived from the recommended values in the aer:
+ * .01 and and 7/8. We use 50 instead of 100 to account for
+ * delayed ack.
+ */
+#define TCP_SCALABLE_AI_CNT	50U
+#define TCP_SCALABLE_MD_SCALE	3
+
+static void tcp_scalable_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt,
+				    u32 in_flight, int flag)
+{
+	if (in_flight < tp->snd_cwnd)
+		return;
+
+	if (tp->snd_cwnd <= tp->snd_ssthresh) {
+		tp->snd_cwnd++;
+	} else {
+		tp->snd_cwnd_cnt++;
+		if (tp->snd_cwnd_cnt > min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)){
+			tp->snd_cwnd++;
+			tp->snd_cwnd_cnt = 0;
+		}
+	}
+	tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp);
+	tp->snd_cwnd_stamp = tcp_time_stamp;
+}
+
+static u32 tcp_scalable_ssthresh(struct tcp_sock *tp)
+{
+	return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U);
+}
+
+
+static struct tcp_congestion_ops tcp_scalable = {
+	.ssthresh	= tcp_scalable_ssthresh,
+	.cong_avoid	= tcp_scalable_cong_avoid,
+	.min_cwnd	= tcp_reno_min_cwnd,
+
+	.owner		= THIS_MODULE,
+	.name		= "scalable",
+};
+
+static int __init tcp_scalable_register(void)
+{
+	return tcp_register_congestion_control(&tcp_scalable);
+}
+
+static void __exit tcp_scalable_unregister(void)
+{
+	tcp_unregister_congestion_control(&tcp_scalable);
+}
+
+module_init(tcp_scalable_register);
+module_exit(tcp_scalable_unregister);
+
+MODULE_AUTHOR("John Heffner");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Scalable TCP");