1 /* Tom Kelly's Scalable TCP
3 * See htt://www-lce.eng.cam.ac.uk/~ctk21/scalable/
5 * John Heffner <jheffner@sc.edu>
8 #include <linux/config.h>
9 #include <linux/module.h>
12 /* These factors derived from the recommended values in the aer:
13 * .01 and and 7/8. We use 50 instead of 100 to account for
16 #define TCP_SCALABLE_AI_CNT 50U
17 #define TCP_SCALABLE_MD_SCALE 3
19 static void tcp_scalable_cong_avoid(struct tcp_sock
*tp
, u32 ack
, u32 rtt
,
20 u32 in_flight
, int flag
)
22 if (in_flight
< tp
->snd_cwnd
)
25 if (tp
->snd_cwnd
<= tp
->snd_ssthresh
) {
29 if (tp
->snd_cwnd_cnt
> min(tp
->snd_cwnd
, TCP_SCALABLE_AI_CNT
)){
34 tp
->snd_cwnd
= min_t(u32
, tp
->snd_cwnd
, tp
->snd_cwnd_clamp
);
35 tp
->snd_cwnd_stamp
= tcp_time_stamp
;
38 static u32
tcp_scalable_ssthresh(struct tcp_sock
*tp
)
40 return max(tp
->snd_cwnd
- (tp
->snd_cwnd
>>TCP_SCALABLE_MD_SCALE
), 2U);
44 static struct tcp_congestion_ops tcp_scalable
= {
45 .ssthresh
= tcp_scalable_ssthresh
,
46 .cong_avoid
= tcp_scalable_cong_avoid
,
47 .min_cwnd
= tcp_reno_min_cwnd
,
53 static int __init
tcp_scalable_register(void)
55 return tcp_register_congestion_control(&tcp_scalable
);
58 static void __exit
tcp_scalable_unregister(void)
60 tcp_unregister_congestion_control(&tcp_scalable
);
63 module_init(tcp_scalable_register
);
64 module_exit(tcp_scalable_unregister
);
66 MODULE_AUTHOR("John Heffner");
67 MODULE_LICENSE("GPL");
68 MODULE_DESCRIPTION("Scalable TCP");