1 files changed, 301 insertions, 235 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3ebf45b38bc3..a27b9c0e27c0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -289,6 +289,7 @@ static bool tcp_ecn_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr
 static void tcp_sndbuf_expand(struct sock *sk)
 {
 	const struct tcp_sock *tp = tcp_sk(sk);
+	const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops;
 	int sndmem, per_mss;
 	u32 nr_segs;
 
@@ -309,7 +310,8 @@ static void tcp_sndbuf_expand(struct sock *sk)
 	 * Cubic needs 1.7 factor, rounded to 2 to include
 	 * extra cushion (application might react slowly to POLLOUT)
 	 */
-	sndmem = 2 * nr_segs * per_mss;
+	sndmem = ca_ops->sndbuf_expand ? ca_ops->sndbuf_expand(sk) : 2;
+	sndmem *= nr_segs * per_mss;
 
 	if (sk->sk_sndbuf < sndmem)
 		sk->sk_sndbuf = min(sndmem, sysctl_tcp_wmem[2]);
@@ -899,12 +901,29 @@ static void tcp_verify_retransmit_hint(struct tcp_sock *tp, struct sk_buff *skb)
 		tp->retransmit_high = TCP_SKB_CB(skb)->end_seq;
 }
 
+/* Sum the number of packets on the wire we have marked as lost.
+ * There are two cases we care about here:
+ * a) Packet hasn't been marked lost (nor retransmitted),
+ *    and this is the first loss.
+ * b) Packet has been marked both lost and retransmitted,
+ *    and this means we think it was lost again.
+ */
+static void tcp_sum_lost(struct tcp_sock *tp, struct sk_buff *skb)
+{
+	__u8 sacked = TCP_SKB_CB(skb)->sacked;
+
+	if (!(sacked & TCPCB_LOST) ||
+	    ((sacked & TCPCB_LOST) && (sacked & TCPCB_SACKED_RETRANS)))
+		tp->lost += tcp_skb_pcount(skb);
+}
+
 static void tcp_skb_mark_lost(struct tcp_sock *tp, struct sk_buff *skb)
 {
 	if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_ACKED))) {
 		tcp_verify_retransmit_hint(tp, skb);
 
 		tp->lost_out += tcp_skb_pcount(skb);
+		tcp_sum_lost(tp, skb);
 		TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
 	}
 }
@@ -913,6 +932,7 @@ void tcp_skb_mark_lost_uncond_verify(struct tcp_sock *tp, struct sk_buff *skb)
 {
 	tcp_verify_retransmit_hint(tp, skb);
 
+	tcp_sum_lost(tp, skb);
 	if (!(TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_ACKED))) {
 		tp->lost_out += tcp_skb_pcount(skb);
 		TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
@@ -1094,6 +1114,7 @@ struct tcp_sacktag_state {
 	 */
 	struct skb_mstamp first_sackt;
 	struct skb_mstamp last_sackt;
+	struct rate_sample *rate;
 	int	flag;
 };
 
@@ -1261,6 +1282,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 	tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,
 			start_seq, end_seq, dup_sack, pcount,
 			&skb->skb_mstamp);
+	tcp_rate_skb_delivered(sk, skb, state->rate);
 
 	if (skb == tp->lost_skb_hint)
 		tp->lost_cnt_hint += pcount;
@@ -1311,6 +1333,9 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 		tcp_advance_highest_sack(sk, skb);
 
 	tcp_skb_collapse_tstamp(prev, skb);
+	if (unlikely(TCP_SKB_CB(prev)->tx.delivered_mstamp.v64))
+		TCP_SKB_CB(prev)->tx.delivered_mstamp.v64 = 0;
+
 	tcp_unlink_write_queue(skb, sk);
 	sk_wmem_free_skb(sk, skb);
 
@@ -1540,6 +1565,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk,
 						dup_sack,
 						tcp_skb_pcount(skb),
 						&skb->skb_mstamp);
+			tcp_rate_skb_delivered(sk, skb, state->rate);
 
 			if (!before(TCP_SKB_CB(skb)->seq,
 				    tcp_highest_sack_seq(tp)))
@@ -1622,8 +1648,10 @@ tcp_sacktag_write_queue(struct sock *sk, const struct sk_buff *ack_skb,
 
 	found_dup_sack = tcp_check_dsack(sk, ack_skb, sp_wire,
 					 num_sacks, prior_snd_una);
-	if (found_dup_sack)
+	if (found_dup_sack) {
 		state->flag |= FLAG_DSACKING_ACK;
+		tp->delivered++; /* A spurious retransmission is delivered */
+	}
 
 	/* Eliminate too old ACKs, but take into
 	 * account more or less fresh ones, they can
@@ -1890,6 +1918,7 @@ void tcp_enter_loss(struct sock *sk)
 	struct sk_buff *skb;
 	bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery;
 	bool is_reneg;			/* is receiver reneging on SACKs? */
+	bool mark_lost;
 
 	/* Reduce ssthresh if it has not yet been made inside this window. */
 	if (icsk->icsk_ca_state <= TCP_CA_Disorder ||
@@ -1923,8 +1952,12 @@ void tcp_enter_loss(struct sock *sk)
 		if (skb == tcp_send_head(sk))
 			break;
 
+		mark_lost = (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) ||
+			     is_reneg);
+		if (mark_lost)
+			tcp_sum_lost(tp, skb);
 		TCP_SKB_CB(skb)->sacked &= (~TCPCB_TAGBITS)|TCPCB_SACKED_ACKED;
-		if (!(TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_ACKED) || is_reneg) {
+		if (mark_lost) {
 			TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_ACKED;
 			TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
 			tp->lost_out += tcp_skb_pcount(skb);
@@ -2329,10 +2362,9 @@ static void DBGUNDO(struct sock *sk, const char *msg)
 	}
 #if IS_ENABLED(CONFIG_IPV6)
 	else if (sk->sk_family == AF_INET6) {
-		struct ipv6_pinfo *np = inet6_sk(sk);
 		pr_debug("Undo %s %pI6/%u c%u l%u ss%u/%u p%u\n",
 			 msg,
-			 &np->daddr, ntohs(inet->inet_dport),
+			 &sk->sk_v6_daddr, ntohs(inet->inet_dport),
 			 tp->snd_cwnd, tcp_left_out(tp),
 			 tp->snd_ssthresh, tp->prior_ssthresh,
 			 tp->packets_out);
@@ -2503,6 +2535,9 @@ static inline void tcp_end_cwnd_reduction(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
+	if (inet_csk(sk)->icsk_ca_ops->cong_control)
+		return;
+
 	/* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */
 	if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR ||
 	    (tp->undo_marker && tp->snd_ssthresh < TCP_INFINITE_SSTHRESH)) {
@@ -2879,67 +2914,13 @@ static void tcp_fastretrans_alert(struct sock *sk, const int acked,
 	*rexmit = REXMIT_LOST;
 }
 
-/* Kathleen Nichols' algorithm for tracking the minimum value of
- * a data stream over some fixed time interval. (E.g., the minimum
- * RTT over the past five minutes.) It uses constant space and constant
- * time per update yet almost always delivers the same minimum as an
- * implementation that has to keep all the data in the window.
- *
- * The algorithm keeps track of the best, 2nd best & 3rd best min
- * values, maintaining an invariant that the measurement time of the
- * n'th best >= n-1'th best. It also makes sure that the three values
- * are widely separated in the time window since that bounds the worse
- * case error when that data is monotonically increasing over the window.
- *
- * Upon getting a new min, we can forget everything earlier because it
- * has no value - the new min is <= everything else in the window by
- * definition and it's the most recent. So we restart fresh on every new min
- * and overwrites 2nd & 3rd choices. The same property holds for 2nd & 3rd
- * best.
- */
 static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us)
 {
-	const u32 now = tcp_time_stamp, wlen = sysctl_tcp_min_rtt_wlen * HZ;
-	struct rtt_meas *m = tcp_sk(sk)->rtt_min;
-	struct rtt_meas rttm = {
-		.rtt = likely(rtt_us) ? rtt_us : jiffies_to_usecs(1),
-		.ts = now,
-	};
-	u32 elapsed;
-
-	/* Check if the new measurement updates the 1st, 2nd, or 3rd choices */
-	if (unlikely(rttm.rtt <= m[0].rtt))
-		m[0] = m[1] = m[2] = rttm;
-	else if (rttm.rtt <= m[1].rtt)
-		m[1] = m[2] = rttm;
-	else if (rttm.rtt <= m[2].rtt)
-		m[2] = rttm;
-
-	elapsed = now - m[0].ts;
-	if (unlikely(elapsed > wlen)) {
-		/* Passed entire window without a new min so make 2nd choice
-		 * the new min & 3rd choice the new 2nd. So forth and so on.
-		 */
-		m[0] = m[1];
-		m[1] = m[2];
-		m[2] = rttm;
-		if (now - m[0].ts > wlen) {
-			m[0] = m[1];
-			m[1] = rttm;
-			if (now - m[0].ts > wlen)
-				m[0] = rttm;
-		}
-	} else if (m[1].ts == m[0].ts && elapsed > wlen / 4) {
-		/* Passed a quarter of the window without a new min so
-		 * take 2nd choice from the 2nd quarter of the window.
-		 */
-		m[2] = m[1] = rttm;
-	} else if (m[2].ts == m[1].ts && elapsed > wlen / 2) {
-		/* Passed half the window without a new min so take the 3rd
-		 * choice from the last half of the window.
-		 */
-		m[2] = rttm;
-	}
+	struct tcp_sock *tp = tcp_sk(sk);
+	u32 wlen = sysctl_tcp_min_rtt_wlen * HZ;
+
+	minmax_running_min(&tp->rtt_min, wlen, tcp_time_stamp,
+			   rtt_us ? : jiffies_to_usecs(1));
 }
 
 static inline bool tcp_ack_update_rtt(struct sock *sk, const int flag,
@@ -3102,10 +3083,11 @@ static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb,
  */
 static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 			       u32 prior_snd_una, int *acked,
-			       struct tcp_sacktag_state *sack)
+			       struct tcp_sacktag_state *sack,
+			       struct skb_mstamp *now)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
-	struct skb_mstamp first_ackt, last_ackt, now;
+	struct skb_mstamp first_ackt, last_ackt;
 	struct tcp_sock *tp = tcp_sk(sk);
 	u32 prior_sacked = tp->sacked_out;
 	u32 reord = tp->packets_out;
@@ -3137,7 +3119,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 			acked_pcount = tcp_tso_acked(sk, skb);
 			if (!acked_pcount)
 				break;
-
 			fully_acked = false;
 		} else {
 			/* Speedup tcp_unlink_write_queue() and next loop */
@@ -3173,6 +3154,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 
 		tp->packets_out -= acked_pcount;
 		pkts_acked += acked_pcount;
+		tcp_rate_skb_delivered(sk, skb, sack->rate);
 
 		/* Initial outgoing SYN's get put onto the write_queue
 		 * just like anything else we transmit.  It is not
@@ -3205,16 +3187,15 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 	if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))
 		flag |= FLAG_SACK_RENEGING;
 
-	skb_mstamp_get(&now);
 	if (likely(first_ackt.v64) && !(flag & FLAG_RETRANS_DATA_ACKED)) {
-		seq_rtt_us = skb_mstamp_us_delta(&now, &first_ackt);
-		ca_rtt_us = skb_mstamp_us_delta(&now, &last_ackt);
+		seq_rtt_us = skb_mstamp_us_delta(now, &first_ackt);
+		ca_rtt_us = skb_mstamp_us_delta(now, &last_ackt);
 	}
 	if (sack->first_sackt.v64) {
-		sack_rtt_us = skb_mstamp_us_delta(&now, &sack->first_sackt);
-		ca_rtt_us = skb_mstamp_us_delta(&now, &sack->last_sackt);
+		sack_rtt_us = skb_mstamp_us_delta(now, &sack->first_sackt);
+		ca_rtt_us = skb_mstamp_us_delta(now, &sack->last_sackt);
 	}
-
+	sack->rate->rtt_us = ca_rtt_us; /* RTT of last (S)ACKed packet, or -1 */
 	rtt_update = tcp_ack_update_rtt(sk, flag, seq_rtt_us, sack_rtt_us,
 					ca_rtt_us);
 
@@ -3242,7 +3223,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 		tp->fackets_out -= min(pkts_acked, tp->fackets_out);
 
 	} else if (skb && rtt_update && sack_rtt_us >= 0 &&
-		   sack_rtt_us > skb_mstamp_us_delta(&now, &skb->skb_mstamp)) {
+		   sack_rtt_us > skb_mstamp_us_delta(now, &skb->skb_mstamp)) {
 		/* Do not re-arm RTO if the sack RTT is measured from data sent
 		 * after when the head was last (re)transmitted. Otherwise the
 		 * timeout may continue to extend in loss recovery.
@@ -3333,8 +3314,15 @@ static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag)
  * information. All transmission or retransmission are delayed afterwards.
  */
 static void tcp_cong_control(struct sock *sk, u32 ack, u32 acked_sacked,
-			     int flag)
+			     int flag, const struct rate_sample *rs)
 {
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+
+	if (icsk->icsk_ca_ops->cong_control) {
+		icsk->icsk_ca_ops->cong_control(sk, rs);
+		return;
+	}
+
 	if (tcp_in_cwnd_reduction(sk)) {
 		/* Reduce cwnd if state mandates */
 		tcp_cwnd_reduction(sk, acked_sacked, flag);
@@ -3579,17 +3567,21 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_sacktag_state sack_state;
+	struct rate_sample rs = { .prior_delivered = 0 };
 	u32 prior_snd_una = tp->snd_una;
 	u32 ack_seq = TCP_SKB_CB(skb)->seq;
 	u32 ack = TCP_SKB_CB(skb)->ack_seq;
 	bool is_dupack = false;
 	u32 prior_fackets;
 	int prior_packets = tp->packets_out;
-	u32 prior_delivered = tp->delivered;
+	u32 delivered = tp->delivered;
+	u32 lost = tp->lost;
 	int acked = 0; /* Number of packets newly acked */
 	int rexmit = REXMIT_NONE; /* Flag to (re)transmit to recover losses */
+	struct skb_mstamp now;
 
 	sack_state.first_sackt.v64 = 0;
+	sack_state.rate = &rs;
 
 	/* We very likely will need to access write queue head. */
 	prefetchw(sk->sk_write_queue.next);
@@ -3612,6 +3604,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	if (after(ack, tp->snd_nxt))
 		goto invalid_ack;
 
+	skb_mstamp_get(&now);
+
 	if (icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
 	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE)
 		tcp_rearm_rto(sk);
@@ -3622,6 +3616,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	}
 
 	prior_fackets = tp->fackets_out;
+	rs.prior_in_flight = tcp_packets_in_flight(tp);
 
 	/* ts_recent update must be made after we are sure that the packet
 	 * is in window.
@@ -3677,7 +3672,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
 	/* See if we can take anything off of the retransmit queue. */
 	flag |= tcp_clean_rtx_queue(sk, prior_fackets, prior_snd_una, &acked,
-				    &sack_state);
+				    &sack_state, &now);
 
 	if (tcp_ack_is_dubious(sk, flag)) {
 		is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP));
@@ -3694,7 +3689,10 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
 	if (icsk->icsk_pending == ICSK_TIME_RETRANS)
 		tcp_schedule_loss_probe(sk);
-	tcp_cong_control(sk, ack, tp->delivered - prior_delivered, flag);
+	delivered = tp->delivered - delivered;	/* freshly ACKed or SACKed */
+	lost = tp->lost - lost;			/* freshly marked lost */
+	tcp_rate_gen(sk, delivered, lost, &now, &rs);
+	tcp_cong_control(sk, ack, delivered, flag, &rs);
 	tcp_xmit_recovery(sk, rexmit);
 	return 1;
 
@@ -4108,7 +4106,7 @@ void tcp_fin(struct sock *sk)
 	/* It _is_ possible, that we have something out-of-order _after_ FIN.
 	 * Probably, we should reset in this case. For now drop them.
 	 */
-	__skb_queue_purge(&tp->out_of_order_queue);
+	skb_rbtree_purge(&tp->out_of_order_queue);
 	if (tcp_is_sack(tp))
 		tcp_sack_reset(&tp->rx_opt);
 	sk_mem_reclaim(sk);
@@ -4268,7 +4266,7 @@ static void tcp_sack_remove(struct tcp_sock *tp)
 	int this_sack;
 
 	/* Empty ofo queue, hence, all the SACKs are eaten. Clear. */
-	if (skb_queue_empty(&tp->out_of_order_queue)) {
+	if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
 		tp->rx_opt.num_sacks = 0;
 		return;
 	}
@@ -4344,10 +4342,13 @@ static void tcp_ofo_queue(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	__u32 dsack_high = tp->rcv_nxt;
+	bool fin, fragstolen, eaten;
 	struct sk_buff *skb, *tail;
-	bool fragstolen, eaten;
+	struct rb_node *p;
 
-	while ((skb = skb_peek(&tp->out_of_order_queue)) != NULL) {
+	p = rb_first(&tp->out_of_order_queue);
+	while (p) {
+		skb = rb_entry(p, struct sk_buff, rbnode);
 		if (after(TCP_SKB_CB(skb)->seq, tp->rcv_nxt))
 			break;
 
@@ -4357,9 +4358,10 @@ static void tcp_ofo_queue(struct sock *sk)
 				dsack_high = TCP_SKB_CB(skb)->end_seq;
 			tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack);
 		}
+		p = rb_next(p);
+		rb_erase(&skb->rbnode, &tp->out_of_order_queue);
 
-		__skb_unlink(skb, &tp->out_of_order_queue);
-		if (!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt)) {
+		if (unlikely(!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))) {
 			SOCK_DEBUG(sk, "ofo packet was already received\n");
 			tcp_drop(sk, skb);
 			continue;
@@ -4371,12 +4373,19 @@ static void tcp_ofo_queue(struct sock *sk)
 		tail = skb_peek_tail(&sk->sk_receive_queue);
 		eaten = tail && tcp_try_coalesce(sk, tail, skb, &fragstolen);
 		tcp_rcv_nxt_update(tp, TCP_SKB_CB(skb)->end_seq);
+		fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
 		if (!eaten)
 			__skb_queue_tail(&sk->sk_receive_queue, skb);
-		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
-			tcp_fin(sk);
-		if (eaten)
+		else
 			kfree_skb_partial(skb, fragstolen);
+
+		if (unlikely(fin)) {
+			tcp_fin(sk);
+			/* tcp_fin() purges tp->out_of_order_queue,
+			 * so we must end this loop right now.
+			 */
+			break;
+		}
 	}
 }
 
@@ -4392,12 +4401,9 @@ static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb,
 		if (tcp_prune_queue(sk) < 0)
 			return -1;
 
-		if (!sk_rmem_schedule(sk, skb, size)) {
+		while (!sk_rmem_schedule(sk, skb, size)) {
 			if (!tcp_prune_ofo_queue(sk))
 				return -1;
-
-			if (!sk_rmem_schedule(sk, skb, size))
-				return -1;
 		}
 	}
 	return 0;
@@ -4406,8 +4412,10 @@ static int tcp_try_rmem_schedule(struct sock *sk, struct sk_buff *skb,
 static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct rb_node **p, *q, *parent;
 	struct sk_buff *skb1;
 	u32 seq, end_seq;
+	bool fragstolen;
 
 	tcp_ecn_check_ce(tp, skb);
 
@@ -4422,88 +4430,92 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 	inet_csk_schedule_ack(sk);
 
 	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE);
+	seq = TCP_SKB_CB(skb)->seq;
+	end_seq = TCP_SKB_CB(skb)->end_seq;
 	SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n",
-		   tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
+		   tp->rcv_nxt, seq, end_seq);
 
-	skb1 = skb_peek_tail(&tp->out_of_order_queue);
-	if (!skb1) {
+	p = &tp->out_of_order_queue.rb_node;
+	if (RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
 		/* Initial out of order segment, build 1 SACK. */
 		if (tcp_is_sack(tp)) {
 			tp->rx_opt.num_sacks = 1;
-			tp->selective_acks[0].start_seq = TCP_SKB_CB(skb)->seq;
-			tp->selective_acks[0].end_seq =
-						TCP_SKB_CB(skb)->end_seq;
+			tp->selective_acks[0].start_seq = seq;
+			tp->selective_acks[0].end_seq = end_seq;
 		}
-		__skb_queue_head(&tp->out_of_order_queue, skb);
+		rb_link_node(&skb->rbnode, NULL, p);
+		rb_insert_color(&skb->rbnode, &tp->out_of_order_queue);
+		tp->ooo_last_skb = skb;
 		goto end;
 	}
 
-	seq = TCP_SKB_CB(skb)->seq;
-	end_seq = TCP_SKB_CB(skb)->end_seq;
-
-	if (seq == TCP_SKB_CB(skb1)->end_seq) {
-		bool fragstolen;
-
-		if (!tcp_try_coalesce(sk, skb1, skb, &fragstolen)) {
-			__skb_queue_after(&tp->out_of_order_queue, skb1, skb);
-		} else {
-			tcp_grow_window(sk, skb);
-			kfree_skb_partial(skb, fragstolen);
-			skb = NULL;
-		}
-
-		if (!tp->rx_opt.num_sacks ||
-		    tp->selective_acks[0].end_seq != seq)
-			goto add_sack;
-
-		/* Common case: data arrive in order after hole. */
-		tp->selective_acks[0].end_seq = end_seq;
-		goto end;
-	}
-
-	/* Find place to insert this segment. */
-	while (1) {
-		if (!after(TCP_SKB_CB(skb1)->seq, seq))
-			break;
-		if (skb_queue_is_first(&tp->out_of_order_queue, skb1)) {
-			skb1 = NULL;
-			break;
-		}
-		skb1 = skb_queue_prev(&tp->out_of_order_queue, skb1);
-	}
-
-	/* Do skb overlap to previous one? */
-	if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) {
-		if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
-			/* All the bits are present. Drop. */
-			NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
-			tcp_drop(sk, skb);
-			skb = NULL;
-			tcp_dsack_set(sk, seq, end_seq);
-			goto add_sack;
+	/* In the typical case, we are adding an skb to the end of the list.
+	 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
+	 */
+	if (tcp_try_coalesce(sk, tp->ooo_last_skb, skb, &fragstolen)) {
+coalesce_done:
+		tcp_grow_window(sk, skb);
+		kfree_skb_partial(skb, fragstolen);
+		skb = NULL;
+		goto add_sack;
+	}
+	/* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */
+	if (!before(seq, TCP_SKB_CB(tp->ooo_last_skb)->end_seq)) {
+		parent = &tp->ooo_last_skb->rbnode;
+		p = &parent->rb_right;
+		goto insert;
+	}
+
+	/* Find place to insert this segment. Handle overlaps on the way. */
+	parent = NULL;
+	while (*p) {
+		parent = *p;
+		skb1 = rb_entry(parent, struct sk_buff, rbnode);
+		if (before(seq, TCP_SKB_CB(skb1)->seq)) {
+			p = &parent->rb_left;
+			continue;
 		}
-		if (after(seq, TCP_SKB_CB(skb1)->seq)) {
-			/* Partial overlap. */
-			tcp_dsack_set(sk, seq,
-				      TCP_SKB_CB(skb1)->end_seq);
-		} else {
-			if (skb_queue_is_first(&tp->out_of_order_queue,
-					       skb1))
-				skb1 = NULL;
-			else
-				skb1 = skb_queue_prev(
-					&tp->out_of_order_queue,
-					skb1);
+		if (before(seq, TCP_SKB_CB(skb1)->end_seq)) {
+			if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
+				/* All the bits are present. Drop. */
+				NET_INC_STATS(sock_net(sk),
+					      LINUX_MIB_TCPOFOMERGE);
+				__kfree_skb(skb);
+				skb = NULL;
+				tcp_dsack_set(sk, seq, end_seq);
+				goto add_sack;
+			}
+			if (after(seq, TCP_SKB_CB(skb1)->seq)) {
+				/* Partial overlap. */
+				tcp_dsack_set(sk, seq, TCP_SKB_CB(skb1)->end_seq);
+			} else {
+				/* skb's seq == skb1's seq and skb covers skb1.
+				 * Replace skb1 with skb.
+				 */
+				rb_replace_node(&skb1->rbnode, &skb->rbnode,
+						&tp->out_of_order_queue);
+				tcp_dsack_extend(sk,
+						 TCP_SKB_CB(skb1)->seq,
+						 TCP_SKB_CB(skb1)->end_seq);
+				NET_INC_STATS(sock_net(sk),
+					      LINUX_MIB_TCPOFOMERGE);
+				__kfree_skb(skb1);
+				goto merge_right;
+			}
+		} else if (tcp_try_coalesce(sk, skb1, skb, &fragstolen)) {
+			goto coalesce_done;
 		}
+		p = &parent->rb_right;
 	}
-	if (!skb1)
-		__skb_queue_head(&tp->out_of_order_queue, skb);
-	else
-		__skb_queue_after(&tp->out_of_order_queue, skb1, skb);
+insert:
+	/* Insert segment into RB tree. */
+	rb_link_node(&skb->rbnode, parent, p);
+	rb_insert_color(&skb->rbnode, &tp->out_of_order_queue);
 
-	/* And clean segments covered by new one as whole. */
-	while (!skb_queue_is_last(&tp->out_of_order_queue, skb)) {
-		skb1 = skb_queue_next(&tp->out_of_order_queue, skb);
+merge_right:
+	/* Remove other segments covered by skb. */
+	while ((q = rb_next(&skb->rbnode)) != NULL) {
+		skb1 = rb_entry(q, struct sk_buff, rbnode);
 
 		if (!after(end_seq, TCP_SKB_CB(skb1)->seq))
 			break;
@@ -4512,12 +4524,15 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 					 end_seq);
 			break;
 		}
-		__skb_unlink(skb1, &tp->out_of_order_queue);
+		rb_erase(&skb1->rbnode, &tp->out_of_order_queue);
 		tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
 				 TCP_SKB_CB(skb1)->end_seq);
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOMERGE);
 		tcp_drop(sk, skb1);
 	}
+	/* If there is no skb after us, we are the last_skb ! */
+	if (!q)
+		tp->ooo_last_skb = skb;
 
 add_sack:
 	if (tcp_is_sack(tp))
@@ -4654,13 +4669,13 @@ queue_and_out:
 		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 			tcp_fin(sk);
 
-		if (!skb_queue_empty(&tp->out_of_order_queue)) {
+		if (!RB_EMPTY_ROOT(&tp->out_of_order_queue)) {
 			tcp_ofo_queue(sk);
 
 			/* RFC2581. 4.2. SHOULD send immediate ACK, when
 			 * gap in queue is filled.
 			 */
-			if (skb_queue_empty(&tp->out_of_order_queue))
+			if (RB_EMPTY_ROOT(&tp->out_of_order_queue))
 				inet_csk(sk)->icsk_ack.pingpong = 0;
 		}
 
@@ -4714,48 +4729,76 @@ drop:
 	tcp_data_queue_ofo(sk, skb);
 }
 
+static struct sk_buff *tcp_skb_next(struct sk_buff *skb, struct sk_buff_head *list)
+{
+	if (list)
+		return !skb_queue_is_last(list, skb) ? skb->next : NULL;
+
+	return rb_entry_safe(rb_next(&skb->rbnode), struct sk_buff, rbnode);
+}
+
 static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb,
-					struct sk_buff_head *list)
+					struct sk_buff_head *list,
+					struct rb_root *root)
 {
-	struct sk_buff *next = NULL;
+	struct sk_buff *next = tcp_skb_next(skb, list);
 
-	if (!skb_queue_is_last(list, skb))
-		next = skb_queue_next(list, skb);
+	if (list)
+		__skb_unlink(skb, list);
+	else
+		rb_erase(&skb->rbnode, root);
 
-	__skb_unlink(skb, list);
 	__kfree_skb(skb);
 	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVCOLLAPSED);
 
 	return next;
 }
 
+/* Insert skb into rb tree, ordered by TCP_SKB_CB(skb)->seq */
+static void tcp_rbtree_insert(struct rb_root *root, struct sk_buff *skb)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct sk_buff *skb1;
+
+	while (*p) {
+		parent = *p;
+		skb1 = rb_entry(parent, struct sk_buff, rbnode);
+		if (before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb1)->seq))
+			p = &parent->rb_left;
+		else
+			p = &parent->rb_right;
+	}
+	rb_link_node(&skb->rbnode, parent, p);
+	rb_insert_color(&skb->rbnode, root);
+}
+
 /* Collapse contiguous sequence of skbs head..tail with
  * sequence numbers start..end.
  *
- * If tail is NULL, this means until the end of the list.
+ * If tail is NULL, this means until the end of the queue.
  *
  * Segments with FIN/SYN are not collapsed (only because this
  * simplifies code)
  */
 static void
-tcp_collapse(struct sock *sk, struct sk_buff_head *list,
-	     struct sk_buff *head, struct sk_buff *tail,
-	     u32 start, u32 end)
+tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root,
+	     struct sk_buff *head, struct sk_buff *tail, u32 start, u32 end)
 {
-	struct sk_buff *skb, *n;
+	struct sk_buff *skb = head, *n;
+	struct sk_buff_head tmp;
 	bool end_of_skbs;
 
 	/* First, check that queue is collapsible and find
-	 * the point where collapsing can be useful. */
-	skb = head;
+	 * the point where collapsing can be useful.
+	 */
 restart:
-	end_of_skbs = true;
-	skb_queue_walk_from_safe(list, skb, n) {
-		if (skb == tail)
-			break;
+	for (end_of_skbs = true; skb != NULL && skb != tail; skb = n) {
+		n = tcp_skb_next(skb, list);
+
 		/* No new bits? It is possible on ofo queue. */
 		if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
-			skb = tcp_collapse_one(sk, skb, list);
+			skb = tcp_collapse_one(sk, skb, list, root);
 			if (!skb)
 				break;
 			goto restart;
@@ -4773,13 +4816,10 @@ restart:
 			break;
 		}
 
-		if (!skb_queue_is_last(list, skb)) {
-			struct sk_buff *next = skb_queue_next(list, skb);
-			if (next != tail &&
-			    TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(next)->seq) {
-				end_of_skbs = false;
-				break;
-			}
+		if (n && n != tail &&
+		    TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(n)->seq) {
+			end_of_skbs = false;
+			break;
 		}
 
 		/* Decided to skip this, advance start seq. */
@@ -4789,17 +4829,22 @@ restart:
 	    (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)))
 		return;
 
+	__skb_queue_head_init(&tmp);
+
 	while (before(start, end)) {
 		int copy = min_t(int, SKB_MAX_ORDER(0, 0), end - start);
 		struct sk_buff *nskb;
 
 		nskb = alloc_skb(copy, GFP_ATOMIC);
 		if (!nskb)
-			return;
+			break;
 
 		memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
 		TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(nskb)->end_seq = start;
-		__skb_queue_before(list, skb, nskb);
+		if (list)
+			__skb_queue_before(list, skb, nskb);
+		else
+			__skb_queue_tail(&tmp, nskb); /* defer rbtree insertion */
 		skb_set_owner_r(nskb, sk);
 
 		/* Copy data, releasing collapsed skbs. */
@@ -4817,14 +4862,17 @@ restart:
 				start += size;
 			}
 			if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
-				skb = tcp_collapse_one(sk, skb, list);
+				skb = tcp_collapse_one(sk, skb, list, root);
 				if (!skb ||
 				    skb == tail ||
 				    (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)))
-					return;
+					goto end;
 			}
 		}
 	}
+end:
+	skb_queue_walk_safe(&tmp, skb, n)
+		tcp_rbtree_insert(root, skb);
 }
 
 /* Collapse ofo queue. Algorithm: select contiguous sequence of skbs
@@ -4833,70 +4881,86 @@ restart:
 static void tcp_collapse_ofo_queue(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	struct sk_buff *skb = skb_peek(&tp->out_of_order_queue);
-	struct sk_buff *head;
+	struct sk_buff *skb, *head;
+	struct rb_node *p;
 	u32 start, end;
 
-	if (!skb)
+	p = rb_first(&tp->out_of_order_queue);
+	skb = rb_entry_safe(p, struct sk_buff, rbnode);
+new_range:
+	if (!skb) {
+		p = rb_last(&tp->out_of_order_queue);
+		/* Note: This is possible p is NULL here. We do not
+		 * use rb_entry_safe(), as ooo_last_skb is valid only
+		 * if rbtree is not empty.
+		 */
+		tp->ooo_last_skb = rb_entry(p, struct sk_buff, rbnode);
 		return;
-
+	}
 	start = TCP_SKB_CB(skb)->seq;
 	end = TCP_SKB_CB(skb)->end_seq;
-	head = skb;
-
-	for (;;) {
-		struct sk_buff *next = NULL;
 
-		if (!skb_queue_is_last(&tp->out_of_order_queue, skb))
-			next = skb_queue_next(&tp->out_of_order_queue, skb);
-		skb = next;
+	for (head = skb;;) {
+		skb = tcp_skb_next(skb, NULL);
 
-		/* Segment is terminated when we see gap or when
-		 * we are at the end of all the queue. */
+		/* Range is terminated when we see a gap or when
+		 * we are at the queue end.
+		 */
 		if (!skb ||
 		    after(TCP_SKB_CB(skb)->seq, end) ||
 		    before(TCP_SKB_CB(skb)->end_seq, start)) {
-			tcp_collapse(sk, &tp->out_of_order_queue,
+			tcp_collapse(sk, NULL, &tp->out_of_order_queue,
 				     head, skb, start, end);
-			head = skb;
-			if (!skb)
-				break;
-			/* Start new segment */
+			goto new_range;
+		}
+
+		if (unlikely(before(TCP_SKB_CB(skb)->seq, start)))
 			start = TCP_SKB_CB(skb)->seq;
+		if (after(TCP_SKB_CB(skb)->end_seq, end))
 			end = TCP_SKB_CB(skb)->end_seq;
-		} else {
-			if (before(TCP_SKB_CB(skb)->seq, start))
-				start = TCP_SKB_CB(skb)->seq;
-			if (after(TCP_SKB_CB(skb)->end_seq, end))
-				end = TCP_SKB_CB(skb)->end_seq;
-		}
 	}
 }
 
 /*
- * Purge the out-of-order queue.
- * Return true if queue was pruned.
+ * Clean the out-of-order queue to make room.
+ * We drop high sequences packets to :
+ * 1) Let a chance for holes to be filled.
+ * 2) not add too big latencies if thousands of packets sit there.
+ *    (But if application shrinks SO_RCVBUF, we could still end up
+ *     freeing whole queue here)
+ *
+ * Return true if queue has shrunk.
  */
 static bool tcp_prune_ofo_queue(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
-	bool res = false;
+	struct rb_node *node, *prev;
 
-	if (!skb_queue_empty(&tp->out_of_order_queue)) {
-		NET_INC_STATS(sock_net(sk), LINUX_MIB_OFOPRUNED);
-		__skb_queue_purge(&tp->out_of_order_queue);
+	if (RB_EMPTY_ROOT(&tp->out_of_order_queue))
+		return false;
 
-		/* Reset SACK state.  A conforming SACK implementation will
-		 * do the same at a timeout based retransmit.  When a connection
-		 * is in a sad state like this, we care only about integrity
-		 * of the connection not performance.
-		 */
-		if (tp->rx_opt.sack_ok)
-			tcp_sack_reset(&tp->rx_opt);
+	NET_INC_STATS(sock_net(sk), LINUX_MIB_OFOPRUNED);
+	node = &tp->ooo_last_skb->rbnode;
+	do {
+		prev = rb_prev(node);
+		rb_erase(node, &tp->out_of_order_queue);
+		tcp_drop(sk, rb_entry(node, struct sk_buff, rbnode));
 		sk_mem_reclaim(sk);
-		res = true;
-	}
-	return res;
+		if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
+		    !tcp_under_memory_pressure(sk))
+			break;
+		node = prev;
+	} while (node);
+	tp->ooo_last_skb = rb_entry(prev, struct sk_buff, rbnode);
+
+	/* Reset SACK state.  A conforming SACK implementation will
+	 * do the same at a timeout based retransmit.  When a connection
+	 * is in a sad state like this, we care only about integrity
+	 * of the connection not performance.
+	 */
+	if (tp->rx_opt.sack_ok)
+		tcp_sack_reset(&tp->rx_opt);
+	return true;
 }
 
 /* Reduce allocated memory if we can, trying to get
@@ -4921,7 +4985,7 @@ static int tcp_prune_queue(struct sock *sk)
 
 	tcp_collapse_ofo_queue(sk);
 	if (!skb_queue_empty(&sk->sk_receive_queue))
-		tcp_collapse(sk, &sk->sk_receive_queue,
+		tcp_collapse(sk, &sk->sk_receive_queue, NULL,
 			     skb_peek(&sk->sk_receive_queue),
 			     NULL,
 			     tp->copied_seq, tp->rcv_nxt);
@@ -5026,7 +5090,7 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible)
 	    /* We ACK each frame or... */
 	    tcp_in_quickack_mode(sk) ||
 	    /* We have out of order data. */
-	    (ofo_possible && skb_peek(&tp->out_of_order_queue))) {
+	    (ofo_possible && !RB_EMPTY_ROOT(&tp->out_of_order_queue))) {
 		/* Then ack it now */
 		tcp_send_ack(sk);
 	} else {
@@ -5885,7 +5949,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		 * so release it.
 		 */
 		if (req) {
-			tp->total_retrans = req->num_retrans;
+			inet_csk(sk)->icsk_retransmits = 0;
 			reqsk_fastopen_remove(sk, req, false);
 		} else {
 			/* Make sure socket is routed, for correct metrics. */
@@ -5927,7 +5991,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		} else
 			tcp_init_metrics(sk);
 
-		tcp_update_pacing_rate(sk);
+		if (!inet_csk(sk)->icsk_ca_ops->cong_control)
+			tcp_update_pacing_rate(sk);
 
 		/* Prevent spurious tcp_cwnd_restart() on first data packet */
 		tp->lsndtime = tcp_time_stamp;
@@ -6260,6 +6325,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 
 	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
 	tcp_openreq_init(req, &tmp_opt, skb, sk);
+	inet_rsk(req)->no_srccheck = inet_sk(sk)->transparent;
 
 	/* Note: tcp_v6_init_req() might override ir_iif for link locals */
 	inet_rsk(req)->ir_iif = inet_request_bound_dev_if(sk, skb);