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 000000000000..70e108e15c71
--- /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");