1 files changed, 69 insertions, 53 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3b81f6df829f..5ee1e1c2082c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -404,6 +404,20 @@ static bool tcp_ecn_rcv_ecn_echo(const struct tcp_sock *tp, const struct tcphdr
 	return false;
 }
 
+static void tcp_count_delivered_ce(struct tcp_sock *tp, u32 ecn_count)
+{
+	tp->delivered_ce += ecn_count;
+}
+
+/* Updates the delivered and delivered_ce counts */
+static void tcp_count_delivered(struct tcp_sock *tp, u32 delivered,
+				bool ece_ack)
+{
+	tp->delivered += delivered;
+	if (ece_ack)
+		tcp_count_delivered_ce(tp, delivered);
+}
+
 /* Buffer size and advertised window tuning.
  *
  * 1. Tuning sk->sk_sndbuf, when connection enters established state.
@@ -635,10 +649,12 @@ EXPORT_SYMBOL(tcp_initialize_rcv_mss);
  */
 static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
 {
-	u32 new_sample = tp->rcv_rtt_est.rtt_us;
-	long m = sample;
+	u32 new_sample, old_sample = tp->rcv_rtt_est.rtt_us;
+	long m = sample << 3;
 
-	if (new_sample != 0) {
+	if (old_sample == 0 || m < old_sample) {
+		new_sample = m;
+	} else {
 		/* If we sample in larger samples in the non-timestamp
 		 * case, we could grossly overestimate the RTT especially
 		 * with chatty applications or bulk transfer apps which
@@ -649,17 +665,9 @@ static void tcp_rcv_rtt_update(struct tcp_sock *tp, u32 sample, int win_dep)
 		 * else with timestamps disabled convergence takes too
 		 * long.
 		 */
-		if (!win_dep) {
-			m -= (new_sample >> 3);
-			new_sample += m;
-		} else {
-			m <<= 3;
-			if (m < new_sample)
-				new_sample = m;
-		}
-	} else {
-		/* No previous measure. */
-		new_sample = m << 3;
+		if (win_dep)
+			return;
+		new_sample = old_sample - (old_sample >> 3) + sample;
 	}
 
 	tp->rcv_rtt_est.rtt_us = new_sample;
@@ -1119,15 +1127,6 @@ void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-/* Updates the delivered and delivered_ce counts */
-static void tcp_count_delivered(struct tcp_sock *tp, u32 delivered,
-				bool ece_ack)
-{
-	tp->delivered += delivered;
-	if (ece_ack)
-		tp->delivered_ce += delivered;
-}
-
 /* This procedure tags the retransmission queue when SACKs arrive.
  *
  * We have three tag bits: SACKED(S), RETRANS(R) and LOST(L).
@@ -2442,20 +2441,33 @@ static inline bool tcp_packet_delayed(const struct tcp_sock *tp)
 {
 	const struct sock *sk = (const struct sock *)tp;
 
-	if (tp->retrans_stamp &&
-	    tcp_tsopt_ecr_before(tp, tp->retrans_stamp))
-		return true;  /* got echoed TS before first retransmission */
+	/* Received an echoed timestamp before the first retransmission? */
+	if (tp->retrans_stamp)
+		return tcp_tsopt_ecr_before(tp, tp->retrans_stamp);
+
+	/* We set tp->retrans_stamp upon the first retransmission of a loss
+	 * recovery episode, so normally if tp->retrans_stamp is 0 then no
+	 * retransmission has happened yet (likely due to TSQ, which can cause
+	 * fast retransmits to be delayed). So if snd_una advanced while
+	 * (tp->retrans_stamp is 0 then apparently a packet was merely delayed,
+	 * not lost. But there are exceptions where we retransmit but then
+	 * clear tp->retrans_stamp, so we check for those exceptions.
+	 */
 
-	/* Check if nothing was retransmitted (retrans_stamp==0), which may
-	 * happen in fast recovery due to TSQ. But we ignore zero retrans_stamp
-	 * in TCP_SYN_SENT, since when we set FLAG_SYN_ACKED we also clear
-	 * retrans_stamp even if we had retransmitted the SYN.
+	/* (1) For non-SACK connections, tcp_is_non_sack_preventing_reopen()
+	 * clears tp->retrans_stamp when snd_una == high_seq.
 	 */
-	if (!tp->retrans_stamp &&	   /* no record of a retransmit/SYN? */
-	    sk->sk_state != TCP_SYN_SENT)  /* not the FLAG_SYN_ACKED case? */
-		return true;  /* nothing was retransmitted */
+	if (!tcp_is_sack(tp) && !before(tp->snd_una, tp->high_seq))
+		return false;
 
-	return false;
+	/* (2) In TCP_SYN_SENT tcp_clean_rtx_queue() clears tp->retrans_stamp
+	 * when setting FLAG_SYN_ACKED is set, even if the SYN was
+	 * retransmitted.
+	 */
+	if (sk->sk_state == TCP_SYN_SENT)
+		return false;
+
+	return true;	/* tp->retrans_stamp is zero; no retransmit yet */
 }
 
 /* Undo procedures. */
@@ -3783,12 +3795,23 @@ static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
 	}
 }
 
-static inline void tcp_in_ack_event(struct sock *sk, u32 flags)
+static void tcp_in_ack_event(struct sock *sk, int flag)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 
-	if (icsk->icsk_ca_ops->in_ack_event)
-		icsk->icsk_ca_ops->in_ack_event(sk, flags);
+	if (icsk->icsk_ca_ops->in_ack_event) {
+		u32 ack_ev_flags = 0;
+
+		if (flag & FLAG_WIN_UPDATE)
+			ack_ev_flags |= CA_ACK_WIN_UPDATE;
+		if (flag & FLAG_SLOWPATH) {
+			ack_ev_flags |= CA_ACK_SLOWPATH;
+			if (flag & FLAG_ECE)
+				ack_ev_flags |= CA_ACK_ECE;
+		}
+
+		icsk->icsk_ca_ops->in_ack_event(sk, ack_ev_flags);
+	}
 }
 
 /* Congestion control has updated the cwnd already. So if we're in
@@ -3905,12 +3928,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 		tcp_snd_una_update(tp, ack);
 		flag |= FLAG_WIN_UPDATE;
 
-		tcp_in_ack_event(sk, CA_ACK_WIN_UPDATE);
-
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPHPACKS);
 	} else {
-		u32 ack_ev_flags = CA_ACK_SLOWPATH;
-
 		if (ack_seq != TCP_SKB_CB(skb)->end_seq)
 			flag |= FLAG_DATA;
 		else
@@ -3922,19 +3941,12 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 			flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una,
 							&sack_state);
 
-		if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) {
+		if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb)))
 			flag |= FLAG_ECE;
-			ack_ev_flags |= CA_ACK_ECE;
-		}
 
 		if (sack_state.sack_delivered)
 			tcp_count_delivered(tp, sack_state.sack_delivered,
 					    flag & FLAG_ECE);
-
-		if (flag & FLAG_WIN_UPDATE)
-			ack_ev_flags |= CA_ACK_WIN_UPDATE;
-
-		tcp_in_ack_event(sk, ack_ev_flags);
 	}
 
 	/* This is a deviation from RFC3168 since it states that:
@@ -3961,6 +3973,8 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
 	tcp_rack_update_reo_wnd(sk, &rs);
 
+	tcp_in_ack_event(sk, flag);
+
 	if (tp->tlp_high_seq)
 		tcp_process_tlp_ack(sk, ack, flag);
 
@@ -3992,6 +4006,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 	return 1;
 
 no_queue:
+	tcp_in_ack_event(sk, flag);
 	/* If data was DSACKed, see if we can undo a cwnd reduction. */
 	if (flag & FLAG_DSACKING_ACK) {
 		tcp_fastretrans_alert(sk, prior_snd_una, num_dupack, &flag,
@@ -4819,8 +4834,9 @@ static void tcp_ofo_queue(struct sock *sk)
 
 		if (before(TCP_SKB_CB(skb)->seq, dsack_high)) {
 			__u32 dsack = dsack_high;
+
 			if (before(TCP_SKB_CB(skb)->end_seq, dsack_high))
-				dsack_high = TCP_SKB_CB(skb)->end_seq;
+				dsack = TCP_SKB_CB(skb)->end_seq;
 			tcp_dsack_extend(sk, TCP_SKB_CB(skb)->seq, dsack);
 		}
 		p = rb_next(p);
@@ -6631,6 +6647,9 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		if (!tp->srtt_us)
 			tcp_synack_rtt_meas(sk, req);
 
+		if (tp->rx_opt.tstamp_ok)
+			tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
+
 		if (req) {
 			tcp_rcv_synrecv_state_fastopen(sk);
 		} else {
@@ -6655,9 +6674,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
 		tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale;
 		tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
 
-		if (tp->rx_opt.tstamp_ok)
-			tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
-
 		if (!inet_csk(sk)->icsk_ca_ops->cong_control)
 			tcp_update_pacing_rate(sk);