| /* |
| * Sally Floyd's High Speed TCP (RFC 3649) congestion control |
| * |
| * See http://www.icir.org/floyd/hstcp.html |
| * |
| * John Heffner <jheffner@psc.edu> |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/module.h> |
| #include <net/tcp.h> |
| |
| |
| /* From AIMD tables from RFC 3649 appendix B, |
| * with fixed-point MD scaled <<8. |
| */ |
| static const struct hstcp_aimd_val { |
| unsigned int cwnd; |
| unsigned int md; |
| } hstcp_aimd_vals[] = { |
| { 38, 128, /* 0.50 */ }, |
| { 118, 112, /* 0.44 */ }, |
| { 221, 104, /* 0.41 */ }, |
| { 347, 98, /* 0.38 */ }, |
| { 495, 93, /* 0.37 */ }, |
| { 663, 89, /* 0.35 */ }, |
| { 851, 86, /* 0.34 */ }, |
| { 1058, 83, /* 0.33 */ }, |
| { 1284, 81, /* 0.32 */ }, |
| { 1529, 78, /* 0.31 */ }, |
| { 1793, 76, /* 0.30 */ }, |
| { 2076, 74, /* 0.29 */ }, |
| { 2378, 72, /* 0.28 */ }, |
| { 2699, 71, /* 0.28 */ }, |
| { 3039, 69, /* 0.27 */ }, |
| { 3399, 68, /* 0.27 */ }, |
| { 3778, 66, /* 0.26 */ }, |
| { 4177, 65, /* 0.26 */ }, |
| { 4596, 64, /* 0.25 */ }, |
| { 5036, 62, /* 0.25 */ }, |
| { 5497, 61, /* 0.24 */ }, |
| { 5979, 60, /* 0.24 */ }, |
| { 6483, 59, /* 0.23 */ }, |
| { 7009, 58, /* 0.23 */ }, |
| { 7558, 57, /* 0.22 */ }, |
| { 8130, 56, /* 0.22 */ }, |
| { 8726, 55, /* 0.22 */ }, |
| { 9346, 54, /* 0.21 */ }, |
| { 9991, 53, /* 0.21 */ }, |
| { 10661, 52, /* 0.21 */ }, |
| { 11358, 52, /* 0.20 */ }, |
| { 12082, 51, /* 0.20 */ }, |
| { 12834, 50, /* 0.20 */ }, |
| { 13614, 49, /* 0.19 */ }, |
| { 14424, 48, /* 0.19 */ }, |
| { 15265, 48, /* 0.19 */ }, |
| { 16137, 47, /* 0.19 */ }, |
| { 17042, 46, /* 0.18 */ }, |
| { 17981, 45, /* 0.18 */ }, |
| { 18955, 45, /* 0.18 */ }, |
| { 19965, 44, /* 0.17 */ }, |
| { 21013, 43, /* 0.17 */ }, |
| { 22101, 43, /* 0.17 */ }, |
| { 23230, 42, /* 0.17 */ }, |
| { 24402, 41, /* 0.16 */ }, |
| { 25618, 41, /* 0.16 */ }, |
| { 26881, 40, /* 0.16 */ }, |
| { 28193, 39, /* 0.16 */ }, |
| { 29557, 39, /* 0.15 */ }, |
| { 30975, 38, /* 0.15 */ }, |
| { 32450, 38, /* 0.15 */ }, |
| { 33986, 37, /* 0.15 */ }, |
| { 35586, 36, /* 0.14 */ }, |
| { 37253, 36, /* 0.14 */ }, |
| { 38992, 35, /* 0.14 */ }, |
| { 40808, 35, /* 0.14 */ }, |
| { 42707, 34, /* 0.13 */ }, |
| { 44694, 33, /* 0.13 */ }, |
| { 46776, 33, /* 0.13 */ }, |
| { 48961, 32, /* 0.13 */ }, |
| { 51258, 32, /* 0.13 */ }, |
| { 53677, 31, /* 0.12 */ }, |
| { 56230, 30, /* 0.12 */ }, |
| { 58932, 30, /* 0.12 */ }, |
| { 61799, 29, /* 0.12 */ }, |
| { 64851, 28, /* 0.11 */ }, |
| { 68113, 28, /* 0.11 */ }, |
| { 71617, 27, /* 0.11 */ }, |
| { 75401, 26, /* 0.10 */ }, |
| { 79517, 26, /* 0.10 */ }, |
| { 84035, 25, /* 0.10 */ }, |
| { 89053, 24, /* 0.10 */ }, |
| }; |
| |
| #define HSTCP_AIMD_MAX ARRAY_SIZE(hstcp_aimd_vals) |
| |
| struct hstcp { |
| u32 ai; |
| }; |
| |
| static void hstcp_init(struct tcp_sock *tp) |
| { |
| struct hstcp *ca = tcp_ca(tp); |
| |
| ca->ai = 0; |
| |
| /* Ensure the MD arithmetic works. This is somewhat pedantic, |
| * since I don't think we will see a cwnd this large. :) */ |
| tp->snd_cwnd_clamp = min_t(u32, tp->snd_cwnd_clamp, 0xffffffff/128); |
| } |
| |
| static void hstcp_cong_avoid(struct tcp_sock *tp, u32 adk, u32 rtt, |
| u32 in_flight, int good) |
| { |
| struct hstcp *ca = tcp_ca(tp); |
| |
| if (in_flight < tp->snd_cwnd) |
| return; |
| |
| if (tp->snd_cwnd <= tp->snd_ssthresh) { |
| if (tp->snd_cwnd < tp->snd_cwnd_clamp) |
| tp->snd_cwnd++; |
| } else { |
| /* Update AIMD parameters */ |
| if (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd) { |
| while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd && |
| ca->ai < HSTCP_AIMD_MAX) |
| ca->ai++; |
| } else if (tp->snd_cwnd < hstcp_aimd_vals[ca->ai].cwnd) { |
| while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd && |
| ca->ai > 0) |
| ca->ai--; |
| } |
| |
| /* Do additive increase */ |
| if (tp->snd_cwnd < tp->snd_cwnd_clamp) { |
| tp->snd_cwnd_cnt += ca->ai; |
| if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { |
| tp->snd_cwnd++; |
| tp->snd_cwnd_cnt -= tp->snd_cwnd; |
| } |
| } |
| } |
| } |
| |
| static u32 hstcp_ssthresh(struct tcp_sock *tp) |
| { |
| struct hstcp *ca = tcp_ca(tp); |
| |
| /* Do multiplicative decrease */ |
| return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U); |
| } |
| |
| |
| static struct tcp_congestion_ops tcp_highspeed = { |
| .init = hstcp_init, |
| .ssthresh = hstcp_ssthresh, |
| .cong_avoid = hstcp_cong_avoid, |
| .min_cwnd = tcp_reno_min_cwnd, |
| |
| .owner = THIS_MODULE, |
| .name = "highspeed" |
| }; |
| |
| static int __init hstcp_register(void) |
| { |
| BUG_ON(sizeof(struct hstcp) > TCP_CA_PRIV_SIZE); |
| return tcp_register_congestion_control(&tcp_highspeed); |
| } |
| |
| static void __exit hstcp_unregister(void) |
| { |
| tcp_unregister_congestion_control(&tcp_highspeed); |
| } |
| |
| module_init(hstcp_register); |
| module_exit(hstcp_unregister); |
| |
| MODULE_AUTHOR("John Heffner"); |
| MODULE_LICENSE("GPL"); |
| MODULE_DESCRIPTION("High Speed TCP"); |