]>
Commit | Line | Data |
---|---|---|
1 | /* Tom Kelly's Scalable TCP | |
2 | * | |
3 | * See http://www.deneholme.net/tom/scalable/ | |
4 | * | |
5 | * John Heffner <jheffner@sc.edu> | |
6 | */ | |
7 | ||
8 | #include <linux/module.h> | |
9 | #include <net/tcp.h> | |
10 | ||
11 | /* These factors derived from the recommended values in the aer: | |
12 | * .01 and and 7/8. We use 50 instead of 100 to account for | |
13 | * delayed ack. | |
14 | */ | |
15 | #define TCP_SCALABLE_AI_CNT 50U | |
16 | #define TCP_SCALABLE_MD_SCALE 3 | |
17 | ||
18 | static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked, | |
19 | u32 in_flight) | |
20 | { | |
21 | struct tcp_sock *tp = tcp_sk(sk); | |
22 | ||
23 | if (!tcp_is_cwnd_limited(sk, in_flight)) | |
24 | return; | |
25 | ||
26 | if (tp->snd_cwnd <= tp->snd_ssthresh) | |
27 | tcp_slow_start(tp, acked); | |
28 | else | |
29 | tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)); | |
30 | } | |
31 | ||
32 | static u32 tcp_scalable_ssthresh(struct sock *sk) | |
33 | { | |
34 | const struct tcp_sock *tp = tcp_sk(sk); | |
35 | return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U); | |
36 | } | |
37 | ||
38 | ||
39 | static struct tcp_congestion_ops tcp_scalable __read_mostly = { | |
40 | .ssthresh = tcp_scalable_ssthresh, | |
41 | .cong_avoid = tcp_scalable_cong_avoid, | |
42 | ||
43 | .owner = THIS_MODULE, | |
44 | .name = "scalable", | |
45 | }; | |
46 | ||
47 | static int __init tcp_scalable_register(void) | |
48 | { | |
49 | return tcp_register_congestion_control(&tcp_scalable); | |
50 | } | |
51 | ||
52 | static void __exit tcp_scalable_unregister(void) | |
53 | { | |
54 | tcp_unregister_congestion_control(&tcp_scalable); | |
55 | } | |
56 | ||
57 | module_init(tcp_scalable_register); | |
58 | module_exit(tcp_scalable_unregister); | |
59 | ||
60 | MODULE_AUTHOR("John Heffner"); | |
61 | MODULE_LICENSE("GPL"); | |
62 | MODULE_DESCRIPTION("Scalable TCP"); |