[mirror_ubuntu-zesty-kernel.git] / net / ipv4 / tcp_illinois.c

/*
 * TCP Illinois congestion control.
 * Home page:
 *	http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
 *
 * The algorithm is described in:
 * "TCP-Illinois: A Loss and Delay-Based Congestion Control Algorithm
 *  for High-Speed Networks"
 * http://www.ifp.illinois.edu/~srikant/Papers/liubassri06perf.pdf
 *
 * Implemented from description in paper and ns-2 simulation.
 * Copyright (C) 2007 Stephen Hemminger <shemminger@linux-foundation.org>
 */

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/inet_diag.h>
#include <asm/div64.h>
#include <net/tcp.h>

#define ALPHA_SHIFT	7
#define ALPHA_SCALE	(1u<<ALPHA_SHIFT)
#define ALPHA_MIN	((3*ALPHA_SCALE)/10)	/* ~0.3 */
#define ALPHA_MAX	(10*ALPHA_SCALE)	/* 10.0 */
#define ALPHA_BASE	ALPHA_SCALE		/* 1.0 */
#define RTT_MAX		(U32_MAX / ALPHA_MAX)	/* 3.3 secs */

#define BETA_SHIFT	6
#define BETA_SCALE	(1u<<BETA_SHIFT)
#define BETA_MIN	(BETA_SCALE/8)		/* 0.125 */
#define BETA_MAX	(BETA_SCALE/2)		/* 0.5 */
#define BETA_BASE	BETA_MAX

static int win_thresh __read_mostly = 15;
module_param(win_thresh, int, 0);
MODULE_PARM_DESC(win_thresh, "Window threshold for starting adaptive sizing");

static int theta __read_mostly = 5;
module_param(theta, int, 0);
MODULE_PARM_DESC(theta, "# of fast RTT's before full growth");

/* TCP Illinois Parameters */
struct illinois {
	u64	sum_rtt;	/* sum of rtt's measured within last rtt */
	u16	cnt_rtt;	/* # of rtts measured within last rtt */
	u32	base_rtt;	/* min of all rtt in usec */
	u32	max_rtt;	/* max of all rtt in usec */
	u32	end_seq;	/* right edge of current RTT */
	u32	alpha;		/* Additive increase */
	u32	beta;		/* Muliplicative decrease */
	u16	acked;		/* # packets acked by current ACK */
	u8	rtt_above;	/* average rtt has gone above threshold */
	u8	rtt_low;	/* # of rtts measurements below threshold */
};

static void rtt_reset(struct sock *sk)
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct illinois *ca = inet_csk_ca(sk);

	ca->end_seq = tp->snd_nxt;
	ca->cnt_rtt = 0;
	ca->sum_rtt = 0;

	/* TODO: age max_rtt? */
}

static void tcp_illinois_init(struct sock *sk)
{
	struct illinois *ca = inet_csk_ca(sk);

	ca->alpha = ALPHA_MAX;
	ca->beta = BETA_BASE;
	ca->base_rtt = 0x7fffffff;
	ca->max_rtt = 0;

	ca->acked = 0;
	ca->rtt_low = 0;
	ca->rtt_above = 0;

	rtt_reset(sk);
}

/* Measure RTT for each ack. */
static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, s32 rtt)
{
	struct illinois *ca = inet_csk_ca(sk);

	ca->acked = pkts_acked;

	/* dup ack, no rtt sample */
	if (rtt < 0)
		return;

	/* ignore bogus values, this prevents wraparound in alpha math */
	if (rtt > RTT_MAX)
		rtt = RTT_MAX;

	/* keep track of minimum RTT seen so far */
	if (ca->base_rtt > rtt)
		ca->base_rtt = rtt;

	/* and max */
	if (ca->max_rtt < rtt)
		ca->max_rtt = rtt;

	++ca->cnt_rtt;
	ca->sum_rtt += rtt;
}

/* Maximum queuing delay */
static inline u32 max_delay(const struct illinois *ca)
{
	return ca->max_rtt - ca->base_rtt;
}

/* Average queuing delay */
static inline u32 avg_delay(const struct illinois *ca)
{
	u64 t = ca->sum_rtt;

	do_div(t, ca->cnt_rtt);
	return t - ca->base_rtt;
}

/*
 * Compute value of alpha used for additive increase.
 * If small window then use 1.0, equivalent to Reno.
 *
 * For larger windows, adjust based on average delay.
 * A. If average delay is at minimum (we are uncongested),
 *    then use large alpha (10.0) to increase faster.
 * B. If average delay is at maximum (getting congested)
 *    then use small alpha (0.3)
 *
 * The result is a convex window growth curve.
 */
static u32 alpha(struct illinois *ca, u32 da, u32 dm)
{
	u32 d1 = dm / 100;	/* Low threshold */

	if (da <= d1) {
		/* If never got out of low delay zone, then use max */
		if (!ca->rtt_above)
			return ALPHA_MAX;

		/* Wait for 5 good RTT's before allowing alpha to go alpha max.
		 * This prevents one good RTT from causing sudden window increase.
		 */
		if (++ca->rtt_low < theta)
			return ca->alpha;

		ca->rtt_low = 0;
		ca->rtt_above = 0;
		return ALPHA_MAX;
	}

	ca->rtt_above = 1;

	/*
	 * Based on:
	 *
	 *      (dm - d1) amin amax
	 * k1 = -------------------
	 *         amax - amin
	 *
	 *       (dm - d1) amin
	 * k2 = ----------------  - d1
	 *        amax - amin
	 *
	 *             k1
	 * alpha = ----------
	 *          k2 + da
	 */

	dm -= d1;
	da -= d1;
	return (dm * ALPHA_MAX) /
		(dm + (da  * (ALPHA_MAX - ALPHA_MIN)) / ALPHA_MIN);
}

/*
 * Beta used for multiplicative decrease.
 * For small window sizes returns same value as Reno (0.5)
 *
 * If delay is small (10% of max) then beta = 1/8
 * If delay is up to 80% of max then beta = 1/2
 * In between is a linear function
 */
static u32 beta(u32 da, u32 dm)
{
	u32 d2, d3;

	d2 = dm / 10;
	if (da <= d2)
		return BETA_MIN;

	d3 = (8 * dm) / 10;
	if (da >= d3 || d3 <= d2)
		return BETA_MAX;

	/*
	 * Based on:
	 *
	 *       bmin d3 - bmax d2
	 * k3 = -------------------
	 *         d3 - d2
	 *
	 *       bmax - bmin
	 * k4 = -------------
	 *         d3 - d2
	 *
	 * b = k3 + k4 da
	 */
	return (BETA_MIN * d3 - BETA_MAX * d2 + (BETA_MAX - BETA_MIN) * da)
		/ (d3 - d2);
}

/* Update alpha and beta values once per RTT */
static void update_params(struct sock *sk)
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct illinois *ca = inet_csk_ca(sk);

	if (tp->snd_cwnd < win_thresh) {
		ca->alpha = ALPHA_BASE;
		ca->beta = BETA_BASE;
	} else if (ca->cnt_rtt > 0) {
		u32 dm = max_delay(ca);
		u32 da = avg_delay(ca);

		ca->alpha = alpha(ca, da, dm);
		ca->beta = beta(da, dm);
	}

	rtt_reset(sk);
}

/*
 * In case of loss, reset to default values
 */
static void tcp_illinois_state(struct sock *sk, u8 new_state)
{
	struct illinois *ca = inet_csk_ca(sk);

	if (new_state == TCP_CA_Loss) {
		ca->alpha = ALPHA_BASE;
		ca->beta = BETA_BASE;
		ca->rtt_low = 0;
		ca->rtt_above = 0;
		rtt_reset(sk);
	}
}

/*
 * Increase window in response to successful acknowledgment.
 */
static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 acked)
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct illinois *ca = inet_csk_ca(sk);

	if (after(ack, ca->end_seq))
		update_params(sk);

	/* RFC2861 only increase cwnd if fully utilized */
	if (!tcp_is_cwnd_limited(sk))
		return;

	/* In slow start */
	if (tcp_in_slow_start(tp))
		tcp_slow_start(tp, acked);

	else {
		u32 delta;

		/* snd_cwnd_cnt is # of packets since last cwnd increment */
		tp->snd_cwnd_cnt += ca->acked;
		ca->acked = 1;

		/* This is close approximation of:
		 * tp->snd_cwnd += alpha/tp->snd_cwnd
		*/
		delta = (tp->snd_cwnd_cnt * ca->alpha) >> ALPHA_SHIFT;
		if (delta >= tp->snd_cwnd) {
			tp->snd_cwnd = min(tp->snd_cwnd + delta / tp->snd_cwnd,
					   (u32)tp->snd_cwnd_clamp);
			tp->snd_cwnd_cnt = 0;
		}
	}
}

static u32 tcp_illinois_ssthresh(struct sock *sk)
{
	struct tcp_sock *tp = tcp_sk(sk);
	struct illinois *ca = inet_csk_ca(sk);

	/* Multiplicative decrease */
	return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->beta) >> BETA_SHIFT), 2U);
}

/* Extract info for Tcp socket info provided via netlink. */
static size_t tcp_illinois_info(struct sock *sk, u32 ext, int *attr,
				union tcp_cc_info *info)
{
	const struct illinois *ca = inet_csk_ca(sk);

	if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
		info->vegas.tcpv_enabled = 1;
		info->vegas.tcpv_rttcnt = ca->cnt_rtt;
		info->vegas.tcpv_minrtt = ca->base_rtt;
		info->vegas.tcpv_rtt = 0;

		if (info->vegas.tcpv_rttcnt > 0) {
			u64 t = ca->sum_rtt;

			do_div(t, info->vegas.tcpv_rttcnt);
			info->vegas.tcpv_rtt = t;
		}
		*attr = INET_DIAG_VEGASINFO;
		return sizeof(struct tcpvegas_info);
	}
	return 0;
}

static struct tcp_congestion_ops tcp_illinois __read_mostly = {
	.init		= tcp_illinois_init,
	.ssthresh	= tcp_illinois_ssthresh,
	.cong_avoid	= tcp_illinois_cong_avoid,
	.set_state	= tcp_illinois_state,
	.get_info	= tcp_illinois_info,
	.pkts_acked	= tcp_illinois_acked,

	.owner		= THIS_MODULE,
	.name		= "illinois",
};

static int __init tcp_illinois_register(void)
{
	BUILD_BUG_ON(sizeof(struct illinois) > ICSK_CA_PRIV_SIZE);
	return tcp_register_congestion_control(&tcp_illinois);
}

static void __exit tcp_illinois_unregister(void)
{
	tcp_unregister_congestion_control(&tcp_illinois);
}

module_init(tcp_illinois_register);
module_exit(tcp_illinois_unregister);

MODULE_AUTHOR("Stephen Hemminger, Shao Liu");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("TCP Illinois");
MODULE_VERSION("1.0");
Commit	Line	Data
c462238d SH	1	/*
	2	* TCP Illinois congestion control.
	3	* Home page:
	4	* http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
	5	*
	6	* The algorithm is described in:
	7	* "TCP-Illinois: A Loss and Delay-Based Congestion Control Algorithm
	8	* for High-Speed Networks"
631dd1a8	9	* http://www.ifp.illinois.edu/~srikant/Papers/liubassri06perf.pdf
c462238d SH	10	*
	11	* Implemented from description in paper and ns-2 simulation.
	12	* Copyright (C) 2007 Stephen Hemminger <shemminger@linux-foundation.org>
	13	*/
	14
	15	#include <linux/module.h>
	16	#include <linux/skbuff.h>
	17	#include <linux/inet_diag.h>
	18	#include <asm/div64.h>
	19	#include <net/tcp.h>
	20
	21	#define ALPHA_SHIFT 7
	22	#define ALPHA_SCALE (1u<<ALPHA_SHIFT)
	23	#define ALPHA_MIN ((3ALPHA_SCALE)/10) / ~0.3 */
	24	#define ALPHA_MAX (10ALPHA_SCALE) / 10.0 */
	25	#define ALPHA_BASE ALPHA_SCALE /* 1.0 */
65d1b4a7	26	#define RTT_MAX (U32_MAX / ALPHA_MAX) /* 3.3 secs */
c462238d SH	27
	28	#define BETA_SHIFT 6
	29	#define BETA_SCALE (1u<<BETA_SHIFT)
65d1b4a7 SH	30	#define BETA_MIN (BETA_SCALE/8) /* 0.125 */
	31	#define BETA_MAX (BETA_SCALE/2) /* 0.5 */
	32	#define BETA_BASE BETA_MAX
c462238d SH	33
c462238d SH	34	static int win_thresh __read_mostly = 15;
65d1b4a7	35	module_param(win_thresh, int, 0);
c462238d SH	36	MODULE_PARM_DESC(win_thresh, "Window threshold for starting adaptive sizing");
c462238d SH	37
65d1b4a7 SH	38	static int theta __read_mostly = 5;
	39	module_param(theta, int, 0);
	40	MODULE_PARM_DESC(theta, "# of fast RTT's before full growth");
c462238d SH	41
c462238d SH	42	/* TCP Illinois Parameters */
65d1b4a7 SH	43	struct illinois {
	44	u64 sum_rtt; /* sum of rtt's measured within last rtt */
	45	u16 cnt_rtt; /* # of rtts measured within last rtt */
	46	u32 base_rtt; /* min of all rtt in usec */
	47	u32 max_rtt; /* max of all rtt in usec */
	48	u32 end_seq; /* right edge of current RTT */
	49	u32 alpha; /* Additive increase */
	50	u32 beta; /* Muliplicative decrease */
	51	u16 acked; /* # packets acked by current ACK */
	52	u8 rtt_above; /* average rtt has gone above threshold */
	53	u8 rtt_low; /* # of rtts measurements below threshold */
c462238d SH	54	};
c462238d SH	55
65d1b4a7 SH	56	static void rtt_reset(struct sock *sk)
	57	{
	58	struct tcp_sock *tp = tcp_sk(sk);
	59	struct illinois *ca = inet_csk_ca(sk);
	60
	61	ca->end_seq = tp->snd_nxt;
	62	ca->cnt_rtt = 0;
	63	ca->sum_rtt = 0;
	64
	65	/* TODO: age max_rtt? */
	66	}
	67
c462238d SH	68	static void tcp_illinois_init(struct sock *sk)
c462238d SH	69	{
65d1b4a7 SH	70	struct illinois *ca = inet_csk_ca(sk);
	71
	72	ca->alpha = ALPHA_MAX;
	73	ca->beta = BETA_BASE;
	74	ca->base_rtt = 0x7fffffff;
	75	ca->max_rtt = 0;
	76
	77	ca->acked = 0;
	78	ca->rtt_low = 0;
	79	ca->rtt_above = 0;
c462238d	80
65d1b4a7	81	rtt_reset(sk);
c462238d SH	82	}
c462238d SH	83
65d1b4a7	84	/* Measure RTT for each ack. */
30cfd0ba	85	static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, s32 rtt)
c462238d	86	{
65d1b4a7	87	struct illinois *ca = inet_csk_ca(sk);
164891aa SH	88
	89	ca->acked = pkts_acked;
	90
30cfd0ba SH	91	/* dup ack, no rtt sample */
30cfd0ba SH	92	if (rtt < 0)
b9ce204f IJ	93	return;
b9ce204f IJ	94
65d1b4a7 SH	95	/* ignore bogus values, this prevents wraparound in alpha math */
	96	if (rtt > RTT_MAX)
	97	rtt = RTT_MAX;
c462238d	98
65d1b4a7 SH	99	/* keep track of minimum RTT seen so far */
	100	if (ca->base_rtt > rtt)
	101	ca->base_rtt = rtt;
	102
	103	/* and max */
	104	if (ca->max_rtt < rtt)
c462238d SH	105	ca->max_rtt = rtt;
c462238d SH	106
65d1b4a7 SH	107	++ca->cnt_rtt;
65d1b4a7 SH	108	ca->sum_rtt += rtt;
c462238d SH	109	}
c462238d SH	110
65d1b4a7 SH	111	/* Maximum queuing delay */
65d1b4a7 SH	112	static inline u32 max_delay(const struct illinois *ca)
c462238d	113	{
65d1b4a7 SH	114	return ca->max_rtt - ca->base_rtt;
65d1b4a7 SH	115	}
c462238d	116
65d1b4a7 SH	117	/* Average queuing delay */
	118	static inline u32 avg_delay(const struct illinois *ca)
	119	{
	120	u64 t = ca->sum_rtt;
c462238d	121
65d1b4a7 SH	122	do_div(t, ca->cnt_rtt);
65d1b4a7 SH	123	return t - ca->base_rtt;
c462238d SH	124	}
	125
	126	/*
	127	* Compute value of alpha used for additive increase.
	128	* If small window then use 1.0, equivalent to Reno.
	129	*
	130	* For larger windows, adjust based on average delay.
	131	* A. If average delay is at minimum (we are uncongested),
	132	* then use large alpha (10.0) to increase faster.
	133	* B. If average delay is at maximum (getting congested)
65d1b4a7	134	* then use small alpha (0.3)
c462238d SH	135	*
	136	* The result is a convex window growth curve.
	137	*/
65d1b4a7	138	static u32 alpha(struct illinois *ca, u32 da, u32 dm)
c462238d	139	{
65d1b4a7	140	u32 d1 = dm / 100; /* Low threshold */
c462238d	141
c462238d	142	if (da <= d1) {
65d1b4a7 SH	143	/* If never got out of low delay zone, then use max */
65d1b4a7 SH	144	if (!ca->rtt_above)
c462238d	145	return ALPHA_MAX;
65d1b4a7 SH	146
	147	/* Wait for 5 good RTT's before allowing alpha to go alpha max.
	148	* This prevents one good RTT from causing sudden window increase.
	149	*/
	150	if (++ca->rtt_low < theta)
	151	return ca->alpha;
	152
	153	ca->rtt_low = 0;
	154	ca->rtt_above = 0;
	155	return ALPHA_MAX;
c462238d SH	156	}
c462238d SH	157
65d1b4a7	158	ca->rtt_above = 1;
c462238d SH	159
	160	/*
	161	* Based on:
	162	*
	163	* (dm - d1) amin amax
	164	* k1 = -------------------
	165	* amax - amin
	166	*
	167	* (dm - d1) amin
	168	* k2 = ---------------- - d1
	169	* amax - amin
	170	*
	171	* k1
	172	* alpha = ----------
	173	* k2 + da
	174	*/
	175
	176	dm -= d1;
	177	da -= d1;
65d1b4a7 SH	178	return (dm * ALPHA_MAX) /
65d1b4a7 SH	179	(dm + (da * (ALPHA_MAX - ALPHA_MIN)) / ALPHA_MIN);
c462238d SH	180	}
	181
	182	/*
	183	* Beta used for multiplicative decrease.
	184	* For small window sizes returns same value as Reno (0.5)
	185	*
	186	* If delay is small (10% of max) then beta = 1/8
	187	* If delay is up to 80% of max then beta = 1/2
	188	* In between is a linear function
	189	*/
65d1b4a7	190	static u32 beta(u32 da, u32 dm)
c462238d	191	{
c462238d SH	192	u32 d2, d3;
c462238d SH	193
c462238d SH	194	d2 = dm / 10;
	195	if (da <= d2)
	196	return BETA_MIN;
65d1b4a7	197
c462238d SH	198	d3 = (8 * dm) / 10;
	199	if (da >= d3 \|\| d3 <= d2)
	200	return BETA_MAX;
	201
	202	/*
	203	* Based on:
	204	*
	205	* bmin d3 - bmax d2
	206	* k3 = -------------------
	207	* d3 - d2
	208	*
	209	* bmax - bmin
	210	* k4 = -------------
	211	* d3 - d2
	212	*
	213	* b = k3 + k4 da
	214	*/
	215	return (BETA_MIN * d3 - BETA_MAX * d2 + (BETA_MAX - BETA_MIN) * da)
	216	/ (d3 - d2);
	217	}
	218
65d1b4a7 SH	219	/* Update alpha and beta values once per RTT */
	220	static void update_params(struct sock *sk)
	221	{
	222	struct tcp_sock *tp = tcp_sk(sk);
	223	struct illinois *ca = inet_csk_ca(sk);
	224
	225	if (tp->snd_cwnd < win_thresh) {
	226	ca->alpha = ALPHA_BASE;
	227	ca->beta = BETA_BASE;
	228	} else if (ca->cnt_rtt > 0) {
	229	u32 dm = max_delay(ca);
	230	u32 da = avg_delay(ca);
	231
	232	ca->alpha = alpha(ca, da, dm);
	233	ca->beta = beta(da, dm);
	234	}
	235
	236	rtt_reset(sk);
	237	}
	238
	239	/*
	240	* In case of loss, reset to default values
	241	*/
	242	static void tcp_illinois_state(struct sock *sk, u8 new_state)
	243	{
	244	struct illinois *ca = inet_csk_ca(sk);
	245
	246	if (new_state == TCP_CA_Loss) {
	247	ca->alpha = ALPHA_BASE;
	248	ca->beta = BETA_BASE;
	249	ca->rtt_low = 0;
	250	ca->rtt_above = 0;
	251	rtt_reset(sk);
	252	}
	253	}
	254
	255	/*
	256	* Increase window in response to successful acknowledgment.
	257	*/
24901551	258	static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 acked)
65d1b4a7 SH	259	{
	260	struct tcp_sock *tp = tcp_sk(sk);
	261	struct illinois *ca = inet_csk_ca(sk);
	262
	263	if (after(ack, ca->end_seq))
	264	update_params(sk);
	265
	266	/* RFC2861 only increase cwnd if fully utilized */
24901551	267	if (!tcp_is_cwnd_limited(sk))
65d1b4a7 SH	268	return;
	269
	270	/* In slow start */
071d5080	271	if (tcp_in_slow_start(tp))
9f9843a7	272	tcp_slow_start(tp, acked);
65d1b4a7 SH	273
	274	else {
	275	u32 delta;
	276
	277	/* snd_cwnd_cnt is # of packets since last cwnd increment */
	278	tp->snd_cwnd_cnt += ca->acked;
	279	ca->acked = 1;
	280
	281	/* This is close approximation of:
	282	* tp->snd_cwnd += alpha/tp->snd_cwnd
	283	*/
	284	delta = (tp->snd_cwnd_cnt * ca->alpha) >> ALPHA_SHIFT;
	285	if (delta >= tp->snd_cwnd) {
	286	tp->snd_cwnd = min(tp->snd_cwnd + delta / tp->snd_cwnd,
688d1945	287	(u32)tp->snd_cwnd_clamp);
65d1b4a7 SH	288	tp->snd_cwnd_cnt = 0;
	289	}
	290	}
	291	}
	292
c462238d SH	293	static u32 tcp_illinois_ssthresh(struct sock *sk)
	294	{
	295	struct tcp_sock *tp = tcp_sk(sk);
65d1b4a7	296	struct illinois *ca = inet_csk_ca(sk);
c462238d SH	297
c462238d SH	298	/* Multiplicative decrease */
a357dde9	299	return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->beta) >> BETA_SHIFT), 2U);
c462238d SH	300	}
c462238d SH	301
65d1b4a7	302	/* Extract info for Tcp socket info provided via netlink. */
64f40ff5 ED	303	static size_t tcp_illinois_info(struct sock sk, u32 ext, int attr,
64f40ff5 ED	304	union tcp_cc_info *info)
c462238d	305	{
65d1b4a7	306	const struct illinois *ca = inet_csk_ca(sk);
c462238d SH	307
c462238d SH	308	if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
64f40ff5 ED	309	info->vegas.tcpv_enabled = 1;
	310	info->vegas.tcpv_rttcnt = ca->cnt_rtt;
	311	info->vegas.tcpv_minrtt = ca->base_rtt;
	312	info->vegas.tcpv_rtt = 0;
65d1b4a7	313
64f40ff5	314	if (info->vegas.tcpv_rttcnt > 0) {
8f363b77	315	u64 t = ca->sum_rtt;
c462238d	316
64f40ff5 ED	317	do_div(t, info->vegas.tcpv_rttcnt);
64f40ff5 ED	318	info->vegas.tcpv_rtt = t;
8f363b77	319	}
64f40ff5 ED	320	*attr = INET_DIAG_VEGASINFO;
64f40ff5 ED	321	return sizeof(struct tcpvegas_info);
c462238d	322	}
521f1cf1	323	return 0;
c462238d SH	324	}
c462238d SH	325
a252bebe	326	static struct tcp_congestion_ops tcp_illinois __read_mostly = {
c462238d SH	327	.init = tcp_illinois_init,
c462238d SH	328	.ssthresh = tcp_illinois_ssthresh,
c462238d	329	.cong_avoid = tcp_illinois_cong_avoid,
65d1b4a7	330	.set_state = tcp_illinois_state,
65d1b4a7 SH	331	.get_info = tcp_illinois_info,
65d1b4a7 SH	332	.pkts_acked = tcp_illinois_acked,
c462238d SH	333
	334	.owner = THIS_MODULE,
	335	.name = "illinois",
	336	};
	337
	338	static int __init tcp_illinois_register(void)
	339	{
65d1b4a7	340	BUILD_BUG_ON(sizeof(struct illinois) > ICSK_CA_PRIV_SIZE);
c462238d SH	341	return tcp_register_congestion_control(&tcp_illinois);
	342	}
	343
	344	static void __exit tcp_illinois_unregister(void)
	345	{
	346	tcp_unregister_congestion_control(&tcp_illinois);
	347	}
	348
	349	module_init(tcp_illinois_register);
	350	module_exit(tcp_illinois_unregister);
	351
	352	MODULE_AUTHOR("Stephen Hemminger, Shao Liu");
	353	MODULE_LICENSE("GPL");
	354	MODULE_DESCRIPTION("TCP Illinois");
65d1b4a7	355	MODULE_VERSION("1.0");