TCP related patches for net-2.6.22

@@ -79,18 +79,19 @@ void tcp_init_congestion_control(struct 
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_congestion_ops *ca;
 
-	if (icsk->icsk_ca_ops != &tcp_init_congestion_ops)
-		return;
+	/* if no choice made yet assign the current value set as default */
+	if (icsk->icsk_ca_ops == &tcp_init_congestion_ops) {
+		rcu_read_lock();
+		list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
+			if (try_module_get(ca->owner)) {
+				icsk->icsk_ca_ops = ca;
+				break;
+			}
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
-		if (try_module_get(ca->owner)) {
-			icsk->icsk_ca_ops = ca;
-			break;
+			/* fallback to next available */
 		}
-
+		rcu_read_unlock();
 	}
-	rcu_read_unlock();
 
 	if (icsk->icsk_ca_ops->init)
 		icsk->icsk_ca_ops->init(sk);

@@ -238,6 +239,7 @@ int tcp_set_congestion_control(struct so
 
 	rcu_read_lock();
 	ca = tcp_ca_find(name);
+
 	/* no change asking for existing value */
 	if (ca == icsk->icsk_ca_ops)
 		goto out;

@@ -263,7 +265,8 @@ int tcp_set_congestion_control(struct so
 	else {
 		tcp_cleanup_congestion_control(sk);
 		icsk->icsk_ca_ops = ca;
-		if (icsk->icsk_ca_ops->init)
+
+		if (sk->sk_state != TCP_CLOSE && icsk->icsk_ca_ops->init)
 			icsk->icsk_ca_ops->init(sk);
 	}
  out:

@@ -23,74 +23,106 @@
 #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 U32_MAX		((u32)~0U)
+#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)		/* 0.8 */
-#define BETA_MAX	(BETA_SCALE/2)
-#define BETA_BASE	BETA_MAX		/* 0.5 */
-
-#define THETA		5
+#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, 0644);
+module_param(win_thresh, int, 0);
 MODULE_PARM_DESC(win_thresh, "Window threshold for starting adaptive sizing");
 
-#define MAX_RTT		0x7fffffff
+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 tcp_illinois {
-	u32	last_alpha;
-	u32	min_rtt;
-	u32	max_rtt;
-	u32	rtt_low;
-	u32	rtt_cnt;
-	u64	sum_rtt;
+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 tcp_illinois *ca = inet_csk_ca(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->last_alpha = ALPHA_BASE;
-	ca->min_rtt = 0x7fffffff;
+	ca->acked = 0;
+	ca->rtt_low = 0;
+	ca->rtt_above = 0;
+
+	rtt_reset(sk);
 }
 
-/*
- * Keep track of min, max and average RTT
- */
-static void tcp_illinois_rtt_calc(struct sock *sk, u32 rtt)
+/* Measure RTT for each ack. */
+static void tcp_illinois_rtt_sample(struct sock *sk, u32 rtt)
 {
-	struct tcp_illinois *ca = inet_csk_ca(sk);
+	struct illinois *ca = inet_csk_ca(sk);
+
+	/* 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;
 
-	if (rtt < ca->min_rtt)
-		ca->min_rtt = rtt;
-	if (rtt > ca->max_rtt)
+	/* and max */
+	if (ca->max_rtt < rtt)
 		ca->max_rtt = rtt;
 
-	if (++ca->rtt_cnt == 1)
-		ca->sum_rtt = rtt;
-	else
-		ca->sum_rtt += rtt;
+	++ca->cnt_rtt;
+	ca->sum_rtt += rtt;
 }
 
-/* max queuing delay */
-static inline u32 max_delay(const struct tcp_illinois *ca)
+/* Capture count of packets covered by ack, to adjust for delayed acks */
+static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked)
 {
-	return ca->max_rtt - ca->min_rtt;
+	struct illinois *ca = inet_csk_ca(sk);
+	ca->acked = pkts_acked;
 }
 
-/* average queueing delay */
-static u32 avg_delay(struct tcp_illinois *ca)
+/* Maximum queuing delay */
+static inline u32 max_delay(const struct illinois *ca)
 {
-	u64 avg_rtt = ca->sum_rtt;
-
-	do_div(avg_rtt, ca->rtt_cnt);
+	return ca->max_rtt - ca->base_rtt;
+}
 
-	ca->sum_rtt = 0;
-	ca->rtt_cnt = 0;
+/* Average queuing delay */
+static inline u32 avg_delay(const struct illinois *ca)
+{
+	u64 t = ca->sum_rtt;
 
-	return avg_rtt - ca->min_rtt;
+	do_div(t, ca->cnt_rtt);
+	return t - ca->base_rtt;
 }
 
 /*

@@ -101,32 +133,31 @@ static u32 avg_delay(struct tcp_illinois
  * 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 (1.0)
+ *    then use small alpha (0.3)
  *
  * The result is a convex window growth curve.
  */
-static u32 alpha(const struct sock *sk)
+static u32 alpha(struct illinois *ca, u32 da, u32 dm)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct tcp_illinois *ca = inet_csk_ca(sk);
-	u32 dm = max_delay(ca);
-	u32 da = avg_delay(ca);
-	u32 d1, a;
-
-	if (tp->snd_cwnd < win_thresh)
-		return ALPHA_BASE;	/* same as Reno (1.0) */
+	u32 d1 = dm / 100;	/* Low threshold */
 
-	d1 = dm / 100;
 	if (da <= d1) {
-		/* Don't let noise force agressive response */
-		if (ca->rtt_low < THETA) {
-			++ca->rtt_low;
-			return ca->last_alpha;
-		} else
+		/* 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_low = 0;
+	ca->rtt_above = 1;
 
 	/*
 	 * Based on:

@@ -146,37 +177,8 @@ static u32 alpha(const struct sock *sk)
 
 	dm -= d1;
 	da -= d1;
-
-	a = (dm * ALPHA_MAX) / (dm - (da  * (ALPHA_MAX - ALPHA_MIN)) / ALPHA_MIN);
-	ca->last_alpha = a;
-	return a;
-}
-
-/*
- * Increase window in response to successful acknowledgment.
- */
-static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
-				    u32 in_flight, int flag)
-{
-	struct tcp_sock *tp = tcp_sk(sk);
-
-	/* RFC2861 only increase cwnd if fully utilized */
-	if (!tcp_is_cwnd_limited(sk, in_flight))
-		return;
-
-	/* In slow start */
-	if (tp->snd_cwnd <= tp->snd_ssthresh)
-		tcp_slow_start(tp);
-
-	else {
-		/* additive increase  cwnd += alpha / cwnd */
-		if ((tp->snd_cwnd_cnt * alpha(sk)) >> ALPHA_SHIFT >= tp->snd_cwnd) {
-			if (tp->snd_cwnd < tp->snd_cwnd_clamp)
-				tp->snd_cwnd++;
-			tp->snd_cwnd_cnt = 0;
-		} else
-			tp->snd_cwnd_cnt++;
-	}
+	return (dm * ALPHA_MAX) /
+		(dm + (da  * (ALPHA_MAX - ALPHA_MIN)) / ALPHA_MIN);
 }
 
 /*

@@ -187,20 +189,14 @@ static void tcp_illinois_cong_avoid(stru
  * If delay is up to 80% of max then beta = 1/2
  * In between is a linear function
  */
-static inline u32 beta(struct sock *sk)
+static u32 beta(u32 da, u32 dm)
 {
-	struct tcp_sock *tp = tcp_sk(sk);
-	struct tcp_illinois *ca = inet_csk_ca(sk);
-	u32 dm = max_delay(ca);
-	u32 da = avg_delay(ca);
 	u32 d2, d3;
 
-	if (tp->snd_cwnd < win_thresh)
-		return BETA_BASE;
-
 	d2 = dm / 10;
 	if (da <= d2)
 		return BETA_MIN;
+
 	d3 = (8 * dm) / 10;
 	if (da >= d3 || d3 <= d2)
 		return BETA_MAX;

@@ -222,31 +218,107 @@ static inline u32 beta(struct sock *sk)
 		/ (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 rtt,
+				    u32 in_flight, int flag)
+{
+	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, in_flight))
+		return;
+
+	/* In slow start */
+	if (tp->snd_cwnd <= tp->snd_ssthresh)
+		tcp_slow_start(tp);
+
+	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 * beta(sk)) >> BETA_SHIFT, 2U);
+	return max((tp->snd_cwnd * ca->beta) >> BETA_SHIFT, 2U);
 }
 
-/* Extract info for TCP socket info provided via netlink.
- * We aren't really doing Vegas, but we can provide RTT info
- */
-static void tcp_illinois_get_info(struct sock *sk, u32 ext,
-			       struct sk_buff *skb)
+
+/* Extract info for Tcp socket info provided via netlink. */
+static void tcp_illinois_info(struct sock *sk, u32 ext,
+			      struct sk_buff *skb)
 {
-	const struct tcp_illinois *ca = inet_csk_ca(sk);
+	const struct illinois *ca = inet_csk_ca(sk);
 
 	if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
 		struct tcpvegas_info info = {
 			.tcpv_enabled = 1,
-			.tcpv_rttcnt = ca->rtt_cnt,
-			.tcpv_minrtt = ca->min_rtt,
+			.tcpv_rttcnt = ca->cnt_rtt,
+			.tcpv_minrtt = ca->base_rtt,
 		};
-		u64 avg_rtt = ca->sum_rtt;
-		do_div(avg_rtt, ca->rtt_cnt);
-		info.tcpv_rtt = avg_rtt;
+		u64 t = ca->sum_rtt;
+
+		do_div(t, ca->cnt_rtt);
+		info.tcpv_rtt = t;
 
 		nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
 	}

@@ -257,8 +329,10 @@ static struct tcp_congestion_ops tcp_ill
 	.ssthresh	= tcp_illinois_ssthresh,
 	.min_cwnd	= tcp_reno_min_cwnd,
 	.cong_avoid	= tcp_illinois_cong_avoid,
-	.rtt_sample	= tcp_illinois_rtt_calc,
-	.get_info	= tcp_illinois_get_info,
+	.set_state	= tcp_illinois_state,
+	.rtt_sample	= tcp_illinois_rtt_sample,
+	.get_info	= tcp_illinois_info,
+	.pkts_acked	= tcp_illinois_acked,
 
 	.owner		= THIS_MODULE,
 	.name		= "illinois",

@@ -266,7 +340,7 @@ static struct tcp_congestion_ops tcp_ill
 
 static int __init tcp_illinois_register(void)
 {
-	BUILD_BUG_ON(sizeof(struct tcp_illinois) > ICSK_CA_PRIV_SIZE);
+	BUILD_BUG_ON(sizeof(struct illinois) > ICSK_CA_PRIV_SIZE);
 	return tcp_register_congestion_control(&tcp_illinois);
 }
 

@@ -281,4 +355,4 @@ module_exit(tcp_illinois_unregister);
 MODULE_AUTHOR("Stephen Hemminger, Shao Liu");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("TCP Illinois");
-MODULE_VERSION("0.3");
+MODULE_VERSION("1.0");

@@ -1569,6 +1569,11 @@ static inline void __net_timestamp(struc
 	skb->tstamp = ktime_get_real();
 }
 
+static inline ktime_t net_timedelta(ktime_t t)
+{
+	return ktime_sub(ktime_get_real(), t);
+}
+
 
 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);

@@ -629,9 +629,12 @@ enum tcp_ca_event {
 #define TCP_CA_MAX	128
 #define TCP_CA_BUF_MAX	(TCP_CA_NAME_MAX*TCP_CA_MAX)
 
+#define TCP_CONG_NON_RESTRICTED 0x1
+#define TCP_CONG_RTT_STAMP	0x2
+
 struct tcp_congestion_ops {
 	struct list_head	list;
-	int	non_restricted;
+	unsigned long flags;
 
 	/* initialize private data (optional) */
 	void (*init)(struct sock *sk);

@@ -645,8 +648,6 @@ struct tcp_congestion_ops {
 	/* do new cwnd calculation (required) */
 	void (*cong_avoid)(struct sock *sk, u32 ack,
 			   u32 rtt, u32 in_flight, int good_ack);
-	/* round trip time sample per acked packet (optional) */
-	void (*rtt_sample)(struct sock *sk, u32 usrtt);
 	/* call before changing ca_state (optional) */
 	void (*set_state)(struct sock *sk, u8 new_state);
 	/* call when cwnd event occurs (optional) */

@@ -654,7 +655,7 @@ struct tcp_congestion_ops {
 	/* new value of cwnd after loss (optional) */
 	u32  (*undo_cwnd)(struct sock *sk);
 	/* hook for packet ack accounting (optional) */
-	void (*pkts_acked)(struct sock *sk, u32 num_acked);
+	void (*pkts_acked)(struct sock *sk, u32 num_acked, ktime_t last);
 	/* get info for inet_diag (optional) */
 	void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
 

@@ -206,7 +206,7 @@ static void bictcp_state(struct sock *sk
 /* Track delayed acknowledgment ratio using sliding window
  * ratio = (15*ratio + sample) / 16
  */
-static void bictcp_acked(struct sock *sk, u32 cnt)
+static void bictcp_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 

@@ -126,7 +126,7 @@ int tcp_set_default_congestion_control(c
 #endif
 
 	if (ca) {
-		ca->non_restricted = 1;	/* default is always allowed */
+		ca->flags |= TCP_CONG_NON_RESTRICTED;	/* default is always allowed */
 		list_move(&ca->list, &tcp_cong_list);
 		ret = 0;
 	}

@@ -181,7 +181,7 @@ void tcp_get_allowed_congestion_control(
 	*buf = '\0';
 	rcu_read_lock();
 	list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
-		if (!ca->non_restricted)
+		if (!(ca->flags & TCP_CONG_NON_RESTRICTED))
 			continue;
 		offs += snprintf(buf + offs, maxlen - offs,
 				 "%s%s",

@@ -212,16 +212,16 @@ int tcp_set_allowed_congestion_control(c
 		}
 	}
 
-	/* pass 2 clear */
+	/* pass 2 clear old values */
 	list_for_each_entry_rcu(ca, &tcp_cong_list, list)
-		ca->non_restricted = 0;
+		ca->flags &= ~TCP_CONG_NON_RESTRICTED;
 
 	/* pass 3 mark as allowed */
 	while ((name = strsep(&val, " ")) && *name) {
 		ca = tcp_ca_find(name);
 		WARN_ON(!ca);
 		if (ca)
-			ca->non_restricted = 1;
+			ca->flags |= TCP_CONG_NON_RESTRICTED;
 	}
 out:
 	spin_unlock(&tcp_cong_list_lock);

@@ -256,7 +256,7 @@ int tcp_set_congestion_control(struct so
 	if (!ca)
 		err = -ENOENT;
 
-	else if (!(ca->non_restricted || capable(CAP_NET_ADMIN)))
+	else if (!((ca->flags & TCP_CONG_NON_RESTRICTED) || capable(CAP_NET_ADMIN)))
 		err = -EPERM;
 
 	else if (!try_module_get(ca->owner))

@@ -371,8 +371,8 @@ u32 tcp_reno_min_cwnd(const struct sock 
 EXPORT_SYMBOL_GPL(tcp_reno_min_cwnd);
 
 struct tcp_congestion_ops tcp_reno = {
+	.flags		= TCP_CONG_NON_RESTRICTED,
 	.name		= "reno",
-	.non_restricted = 1,
 	.owner		= THIS_MODULE,
 	.ssthresh	= tcp_reno_ssthresh,
 	.cong_avoid	= tcp_reno_cong_avoid,

@@ -334,7 +334,7 @@ static void bictcp_state(struct sock *sk
 /* Track delayed acknowledgment ratio using sliding window
  * ratio = (15*ratio + sample) / 16
  */
-static void bictcp_acked(struct sock *sk, u32 cnt)
+static void bictcp_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 

@@ -98,7 +98,7 @@ static inline void measure_rtt(struct so
 	}
 }
 
-static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked)
+static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked, ktime_t last)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	const struct tcp_sock *tp = tcp_sk(sk);

@@ -83,9 +83,14 @@ static void tcp_illinois_init(struct soc
 }
 
 /* Measure RTT for each ack. */
-static void tcp_illinois_rtt_sample(struct sock *sk, u32 rtt)
+static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
 {
 	struct illinois *ca = inet_csk_ca(sk);
+	u32 rtt;
+
+	ca->acked = pkts_acked;
+
+	rtt = ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC;
 
 	/* ignore bogus values, this prevents wraparound in alpha math */
 	if (rtt > RTT_MAX)

@@ -103,13 +108,6 @@ static void tcp_illinois_rtt_sample(stru
 	ca->sum_rtt += rtt;
 }
 
-/* Capture count of packets covered by ack, to adjust for delayed acks */
-static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked)
-{
-	struct illinois *ca = inet_csk_ca(sk);
-	ca->acked = pkts_acked;
-}
-
 /* Maximum queuing delay */
 static inline u32 max_delay(const struct illinois *ca)
 {

@@ -325,12 +323,12 @@ static void tcp_illinois_info(struct soc
 }
 
 static struct tcp_congestion_ops tcp_illinois = {
+	.flags		= TCP_CONG_RTT_STAMP,
 	.init		= tcp_illinois_init,
 	.ssthresh	= tcp_illinois_ssthresh,
 	.min_cwnd	= tcp_reno_min_cwnd,
 	.cong_avoid	= tcp_illinois_cong_avoid,
 	.set_state	= tcp_illinois_state,
-	.rtt_sample	= tcp_illinois_rtt_sample,
 	.get_info	= tcp_illinois_info,
 	.pkts_acked	= tcp_illinois_acked,
 

@@ -2402,14 +2402,6 @@ static int tcp_tso_acked(struct sock *sk
 	return acked;
 }
 
-static u32 tcp_usrtt(struct timeval *tv)
-{
-	struct timeval now;
-
-	do_gettimeofday(&now);
-	return (now.tv_sec - tv->tv_sec) * 1000000 + (now.tv_usec - tv->tv_usec);
-}
-
 /* Remove acknowledged frames from the retransmission queue. */
 static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 {

@@ -2420,9 +2412,7 @@ static int tcp_clean_rtx_queue(struct so
 	int acked = 0;
 	__s32 seq_rtt = -1;
 	u32 pkts_acked = 0;
-	void (*rtt_sample)(struct sock *sk, u32 usrtt)
-		= icsk->icsk_ca_ops->rtt_sample;
-	struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
+	ktime_t last_ackt = ktime_set(0,0);
 
 	while ((skb = tcp_write_queue_head(sk)) &&
 	       skb != tcp_send_head(sk)) {

@@ -2471,7 +2461,7 @@ static int tcp_clean_rtx_queue(struct so
 				seq_rtt = -1;
 			} else if (seq_rtt < 0) {
 				seq_rtt = now - scb->when;
-				skb_get_timestamp(skb, &tv);
+				last_ackt = skb->tstamp;
 			}
 			if (sacked & TCPCB_SACKED_ACKED)
 				tp->sacked_out -= tcp_skb_pcount(skb);

@@ -2484,7 +2474,7 @@ static int tcp_clean_rtx_queue(struct so
 			}
 		} else if (seq_rtt < 0) {
 			seq_rtt = now - scb->when;
-			skb_get_timestamp(skb, &tv);
+			last_ackt = skb->tstamp;
 		}
 		tcp_dec_pcount_approx(&tp->fackets_out, skb);
 		tcp_packets_out_dec(tp, skb);

@@ -2494,13 +2484,14 @@ static int tcp_clean_rtx_queue(struct so
 	}
 
 	if (acked&FLAG_ACKED) {
+		const struct tcp_congestion_ops *ca_ops
+			= inet_csk(sk)->icsk_ca_ops;
+
 		tcp_ack_update_rtt(sk, acked, seq_rtt);
 		tcp_ack_packets_out(sk);
-		if (rtt_sample && !(acked & FLAG_RETRANS_DATA_ACKED))
-			(*rtt_sample)(sk, tcp_usrtt(&tv));
 
-		if (icsk->icsk_ca_ops->pkts_acked)
-			icsk->icsk_ca_ops->pkts_acked(sk, pkts_acked);
+		if (ca_ops->pkts_acked)
+			ca_ops->pkts_acked(sk, pkts_acked, last_ackt);
 	}
 
 #if FASTRETRANS_DEBUG > 0

@@ -218,7 +218,7 @@ static u32 tcp_lp_owd_calculator(struct 
  *   3. calc smoothed OWD (SOWD).
  * Most ideas come from the original TCP-LP implementation.
  */
-static void tcp_lp_rtt_sample(struct sock *sk, u32 usrtt)
+static void tcp_lp_rtt_sample(struct sock *sk, u32 rtt)
 {
 	struct lp *lp = inet_csk_ca(sk);
 	s64 mowd = tcp_lp_owd_calculator(sk);

@@ -261,11 +261,13 @@ static void tcp_lp_rtt_sample(struct soc
  * newReno in increase case.
  * We work it out by following the idea from TCP-LP's paper directly
  */
-static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked)
+static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, ktime_t last)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct lp *lp = inet_csk_ca(sk);
 
+	tcp_lp_rtt_sample(sk,  ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC);
+
 	/* calc inference */
 	if (tcp_time_stamp > tp->rx_opt.rcv_tsecr)
 		lp->inference = 3 * (tcp_time_stamp - tp->rx_opt.rcv_tsecr);

@@ -312,11 +314,11 @@ static void tcp_lp_pkts_acked(struct soc
 }
 
 static struct tcp_congestion_ops tcp_lp = {
+	.flags = TCP_CONG_RTT_STAMP,
 	.init = tcp_lp_init,
 	.ssthresh = tcp_reno_ssthresh,
 	.cong_avoid = tcp_lp_cong_avoid,
 	.min_cwnd = tcp_reno_min_cwnd,
-	.rtt_sample = tcp_lp_rtt_sample,
 	.pkts_acked = tcp_lp_pkts_acked,
 
 	.owner = THIS_MODULE,

@@ -409,7 +409,7 @@ static int tcp_transmit_skb(struct sock 
 	/* If congestion control is doing timestamping, we must
 	 * take such a timestamp before we potentially clone/copy.
 	 */
-	if (icsk->icsk_ca_ops->rtt_sample)
+	if (icsk->icsk_ca_ops->flags & TCP_CONG_RTT_STAMP)
 		__net_timestamp(skb);
 
 	if (likely(clone_it)) {

@@ -120,10 +120,13 @@ static void tcp_vegas_init(struct sock *
  *   o min-filter RTT samples from a much longer window (forever for now)
  *     to find the propagation delay (baseRTT)
  */
-static void tcp_vegas_rtt_calc(struct sock *sk, u32 usrtt)
+static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	struct vegas *vegas = inet_csk_ca(sk);
-	u32 vrtt = usrtt + 1; /* Never allow zero rtt or baseRTT */
+	u32 vrtt;
+
+	/* Never allow zero rtt or baseRTT */
+	vrtt = (ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC) + 1;
 
 	/* Filter to find propagation delay: */
 	if (vrtt < vegas->baseRTT)

@@ -353,11 +356,12 @@ static void tcp_vegas_get_info(struct so
 }
 
 static struct tcp_congestion_ops tcp_vegas = {
+	.flags		= TCP_CONG_RTT_STAMP,
 	.init		= tcp_vegas_init,
 	.ssthresh	= tcp_reno_ssthresh,
 	.cong_avoid	= tcp_vegas_cong_avoid,
 	.min_cwnd	= tcp_reno_min_cwnd,
-	.rtt_sample	= tcp_vegas_rtt_calc,
+	.pkts_acked	= tcp_vegas_pkts_acked,
 	.set_state	= tcp_vegas_state,
 	.cwnd_event	= tcp_vegas_cwnd_event,
 	.get_info	= tcp_vegas_get_info,

@@ -69,10 +69,13 @@ static void tcp_veno_init(struct sock *s
 }
 
 /* Do rtt sampling needed for Veno. */
-static void tcp_veno_rtt_calc(struct sock *sk, u32 usrtt)
+static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	struct veno *veno = inet_csk_ca(sk);
-	u32 vrtt = usrtt + 1;	/* Never allow zero rtt or basertt */
+	u32 vrtt;
+
+	/* Never allow zero rtt or baseRTT */
+	vrtt = (ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC) + 1;
 
 	/* Filter to find propagation delay: */
 	if (vrtt < veno->basertt)

@@ -199,10 +202,11 @@ static u32 tcp_veno_ssthresh(struct sock
 }
 
 static struct tcp_congestion_ops tcp_veno = {
+	.flags		= TCP_CONG_RTT_STAMP,
 	.init		= tcp_veno_init,
 	.ssthresh	= tcp_veno_ssthresh,
 	.cong_avoid	= tcp_veno_cong_avoid,
-	.rtt_sample	= tcp_veno_rtt_calc,
+	.pkts_acked	= tcp_veno_pkts_acked,
 	.set_state	= tcp_veno_state,
 	.cwnd_event	= tcp_veno_cwnd_event,
 

@@ -100,7 +100,7 @@ static void westwood_filter(struct westw
  * Called after processing group of packets.
  * but all westwood needs is the last sample of srtt.
  */
-static void tcp_westwood_pkts_acked(struct sock *sk, u32 cnt)
+static void tcp_westwood_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	struct westwood *w = inet_csk_ca(sk);
 	if (cnt > 0)

@@ -64,13 +64,15 @@ static void tcp_yeah_init(struct sock *s
 }
 
 
-static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked)
+static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	struct yeah *yeah = inet_csk_ca(sk);
 
 	if (icsk->icsk_ca_state == TCP_CA_Open)
 		yeah->pkts_acked = pkts_acked;
+
+	tcp_vegas_pkts_acked(sk, pkts_acked, last);
 }
 
 static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,

@@ -237,11 +239,11 @@ static u32 tcp_yeah_ssthresh(struct sock
 }
 
 static struct tcp_congestion_ops tcp_yeah = {
+	.flags		= TCP_CONG_RTT_STAMP,
 	.init		= tcp_yeah_init,
 	.ssthresh	= tcp_yeah_ssthresh,
 	.cong_avoid	= tcp_yeah_cong_avoid,
 	.min_cwnd	= tcp_reno_min_cwnd,
-	.rtt_sample	= tcp_vegas_rtt_calc,
 	.set_state	= tcp_vegas_state,
 	.cwnd_event	= tcp_vegas_cwnd_event,
 	.get_info	= tcp_vegas_get_info,

@@ -81,10 +81,13 @@ static void tcp_vegas_state(struct sock 
  *   o min-filter RTT samples from a much longer window (forever for now)
  *     to find the propagation delay (baseRTT)
  */
-static void tcp_vegas_rtt_calc(struct sock *sk, u32 usrtt)
+static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	struct vegas *vegas = inet_csk_ca(sk);
-	u32 vrtt = usrtt + 1; /* Never allow zero rtt or baseRTT */
+	u32 vrtt;
+
+	/* Never allow zero rtt or baseRTT */
+	vrtt = (ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC) + 1;
 
 	/* Filter to find propagation delay: */
 	if (vrtt < vegas->baseRTT)

@@ -38,6 +38,8 @@
 
 #include <net/tcp.h>
 
+#include "tcp_vegas.h"
+
 /* Default values of the Vegas variables, in fixed-point representation
  * with V_PARAM_SHIFT bits to the right of the binary point.
  */

@@ -54,17 +56,6 @@ module_param(gamma, int, 0644);
 MODULE_PARM_DESC(gamma, "limit on increase (scale by 2)");
 
 
-/* Vegas variables */
-struct vegas {
-	u32	beg_snd_nxt;	/* right edge during last RTT */
-	u32	beg_snd_una;	/* left edge  during last RTT */
-	u32	beg_snd_cwnd;	/* saves the size of the cwnd */
-	u8	doing_vegas_now;/* if true, do vegas for this RTT */
-	u16	cntRTT;		/* # of RTTs measured within last RTT */
-	u32	minRTT;		/* min of RTTs measured within last RTT (in usec) */
-	u32	baseRTT;	/* the min of all Vegas RTT measurements seen (in usec) */
-};
-
 /* There are several situations when we must "re-start" Vegas:
  *
  *  o when a connection is established

@@ -81,7 +72,7 @@ struct vegas {
  * Instead we must wait until the completion of an RTT during
  * which we actually receive ACKs.
  */
-static inline void vegas_enable(struct sock *sk)
+static void vegas_enable(struct sock *sk)
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
 	struct vegas *vegas = inet_csk_ca(sk);

@@ -104,13 +95,14 @@ static inline void vegas_disable(struct 
 	vegas->doing_vegas_now = 0;
 }
 
-static void tcp_vegas_init(struct sock *sk)
+void tcp_vegas_init(struct sock *sk)
 {
 	struct vegas *vegas = inet_csk_ca(sk);
 
 	vegas->baseRTT = 0x7fffffff;
 	vegas_enable(sk);
 }
+EXPORT_SYMBOL_GPL(tcp_vegas_init);
 
 /* Do RTT sampling needed for Vegas.
  * Basically we:

@@ -120,7 +112,7 @@ static void tcp_vegas_init(struct sock *
  *   o min-filter RTT samples from a much longer window (forever for now)
  *     to find the propagation delay (baseRTT)
  */
-static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
+void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
 	struct vegas *vegas = inet_csk_ca(sk);
 	u32 vrtt;

@@ -138,8 +130,9 @@ static void tcp_vegas_pkts_acked(struct 
 	vegas->minRTT = min(vegas->minRTT, vrtt);
 	vegas->cntRTT++;
 }
+EXPORT_SYMBOL_GPL(tcp_vegas_pkts_acked);
 
-static void tcp_vegas_state(struct sock *sk, u8 ca_state)
+void tcp_vegas_state(struct sock *sk, u8 ca_state)
 {
 
 	if (ca_state == TCP_CA_Open)

@@ -147,6 +140,7 @@ static void tcp_vegas_state(struct sock 
 	else
 		vegas_disable(sk);
 }
+EXPORT_SYMBOL_GPL(tcp_vegas_state);
 
 /*
  * If the connection is idle and we are restarting,

@@ -157,12 +151,13 @@ static void tcp_vegas_state(struct sock 
  * packets, _then_ we can make Vegas calculations
  * again.
  */
-static void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event)
+void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event)
 {
 	if (event == CA_EVENT_CWND_RESTART ||
 	    event == CA_EVENT_TX_START)
 		tcp_vegas_init(sk);
 }
+EXPORT_SYMBOL_GPL(tcp_vegas_cwnd_event);
 
 static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack,
 				 u32 seq_rtt, u32 in_flight, int flag)

@@ -339,8 +334,7 @@ static void tcp_vegas_cong_avoid(struct 
 }
 
 /* Extract info for Tcp socket info provided via netlink. */
-static void tcp_vegas_get_info(struct sock *sk, u32 ext,
-			       struct sk_buff *skb)
+void tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb)
 {
 	const struct vegas *ca = inet_csk_ca(sk);
 	if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {

@@ -354,6 +348,7 @@ static void tcp_vegas_get_info(struct so
 		nla_put(skb, INET_DIAG_VEGASINFO, sizeof(info), &info);
 	}
 }
+EXPORT_SYMBOL_GPL(tcp_vegas_get_info);
 
 static struct tcp_congestion_ops tcp_vegas = {
 	.flags		= TCP_CONG_RTT_STAMP,

@@ -0,0 +1,24 @@
+/*
+ * TCP Vegas congestion control interface
+ */
+#ifndef __TCP_VEGAS_H
+#define __TCP_VEGAS_H 1
+
+/* Vegas variables */
+struct vegas {
+	u32	beg_snd_nxt;	/* right edge during last RTT */
+	u32	beg_snd_una;	/* left edge  during last RTT */
+	u32	beg_snd_cwnd;	/* saves the size of the cwnd */
+	u8	doing_vegas_now;/* if true, do vegas for this RTT */
+	u16	cntRTT;		/* # of RTTs measured within last RTT */
+	u32	minRTT;		/* min of RTTs measured within last RTT (in usec) */
+	u32	baseRTT;	/* the min of all Vegas RTT measurements seen (in usec) */
+};
+
+extern void tcp_vegas_init(struct sock *sk);
+extern void tcp_vegas_state(struct sock *sk, u8 ca_state);
+extern void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last);
+extern void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event);
+extern void tcp_vegas_get_info(struct sock *sk, u32 ext, struct sk_buff *skb);
+
+#endif	/* __TCP_VEGAS_H */

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