1 files changed, 21 insertions, 12 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e1eb56e21dd5..99ab936a9cd3 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -616,7 +616,8 @@ static unsigned int tcp_synack_options(struct request_sock *req,
 				       unsigned int mss, struct sk_buff *skb,
 				       struct tcp_out_options *opts,
 				       const struct tcp_md5sig_key *md5,
-				       struct tcp_fastopen_cookie *foc)
+				       struct tcp_fastopen_cookie *foc,
+				       enum tcp_synack_type synack_type)
 {
 	struct inet_request_sock *ireq = inet_rsk(req);
 	unsigned int remaining = MAX_TCP_OPTION_SPACE;
@@ -631,7 +632,8 @@ static unsigned int tcp_synack_options(struct request_sock *req,
 		 * rather than TS in order to fit in better with old,
 		 * buggy kernels, but that was deemed to be unnecessary.
 		 */
-		ireq->tstamp_ok &= !ireq->sack_ok;
+		if (synack_type != TCP_SYNACK_COOKIE)
+			ireq->tstamp_ok &= !ireq->sack_ok;
 	}
 #endif
 
@@ -1468,6 +1470,7 @@ int tcp_mtu_to_mss(struct sock *sk, int pmtu)
 	return __tcp_mtu_to_mss(sk, pmtu) -
 	       (tcp_sk(sk)->tcp_header_len - sizeof(struct tcphdr));
 }
+EXPORT_SYMBOL(tcp_mtu_to_mss);
 
 /* Inverse of above */
 int tcp_mss_to_mtu(struct sock *sk, int mss)
@@ -1618,7 +1621,8 @@ static void tcp_cwnd_validate(struct sock *sk, bool is_cwnd_limited)
 	 * window, and remember whether we were cwnd-limited then.
 	 */
 	if (!before(tp->snd_una, tp->max_packets_seq) ||
-	    tp->packets_out > tp->max_packets_out) {
+	    tp->packets_out > tp->max_packets_out ||
+	    is_cwnd_limited) {
 		tp->max_packets_out = tp->packets_out;
 		tp->max_packets_seq = tp->snd_nxt;
 		tp->is_cwnd_limited = is_cwnd_limited;
@@ -2409,6 +2413,10 @@ repair:
 	else
 		tcp_chrono_stop(sk, TCP_CHRONO_RWND_LIMITED);
 
+	is_cwnd_limited |= (tcp_packets_in_flight(tp) >= tp->snd_cwnd);
+	if (likely(sent_pkts || is_cwnd_limited))
+		tcp_cwnd_validate(sk, is_cwnd_limited);
+
 	if (likely(sent_pkts)) {
 		if (tcp_in_cwnd_reduction(sk))
 			tp->prr_out += sent_pkts;
@@ -2416,8 +2424,6 @@ repair:
 		/* Send one loss probe per tail loss episode. */
 		if (push_one != 2)
 			tcp_schedule_loss_probe(sk, false);
-		is_cwnd_limited |= (tcp_packets_in_flight(tp) >= tp->snd_cwnd);
-		tcp_cwnd_validate(sk, is_cwnd_limited);
 		return false;
 	}
 	return !tp->packets_out && tcp_send_head(sk);
@@ -2498,6 +2504,11 @@ void tcp_send_loss_probe(struct sock *sk)
 	int pcount;
 	int mss = tcp_current_mss(sk);
 
+	/* At most one outstanding TLP */
+	if (tp->tlp_high_seq)
+		goto rearm_timer;
+
+	tp->tlp_retrans = 0;
 	skb = tcp_send_head(sk);
 	if (skb) {
 		if (tcp_snd_wnd_test(tp, skb, mss)) {
@@ -2520,10 +2531,6 @@ void tcp_send_loss_probe(struct sock *sk)
 		return;
 	}
 
-	/* At most one outstanding TLP retransmission. */
-	if (tp->tlp_high_seq)
-		goto rearm_timer;
-
 	if (skb_still_in_host_queue(sk, skb))
 		goto rearm_timer;
 
@@ -2544,10 +2551,12 @@ void tcp_send_loss_probe(struct sock *sk)
 	if (__tcp_retransmit_skb(sk, skb, 1))
 		goto rearm_timer;
 
+	tp->tlp_retrans = 1;
+
+probe_sent:
 	/* Record snd_nxt for loss detection. */
 	tp->tlp_high_seq = tp->snd_nxt;
 
-probe_sent:
 	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPLOSSPROBES);
 	/* Reset s.t. tcp_rearm_rto will restart timer from now */
 	inet_csk(sk)->icsk_pending = 0;
@@ -3252,8 +3261,8 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
 	md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req));
 #endif
 	skb_set_hash(skb, tcp_rsk(req)->txhash, PKT_HASH_TYPE_L4);
-	tcp_header_size = tcp_synack_options(req, mss, skb, &opts, md5, foc) +
-			  sizeof(*th);
+	tcp_header_size = tcp_synack_options(req, mss, skb, &opts, md5,
+					     foc, synack_type) + sizeof(*th);
 
 	skb_push(skb, tcp_header_size);
 	skb_reset_transport_header(skb);