1 files changed, 25 insertions, 12 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 29f3df4ddd1f..9382caeb721a 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1225,7 +1225,7 @@ static u8 tcp_sacktag_one(struct sock *sk,
 	if (dup_sack && (sacked & TCPCB_RETRANS)) {
 		if (tp->undo_marker && tp->undo_retrans > 0 &&
 		    after(end_seq, tp->undo_marker))
-			tp->undo_retrans--;
+			tp->undo_retrans = max_t(int, 0, tp->undo_retrans - pcount);
 		if (sacked & TCPCB_SACKED_ACKED)
 			state->reord = min(fack_count, state->reord);
 	}
@@ -2803,7 +2803,8 @@ static void tcp_rack_identify_loss(struct sock *sk, int *ack_flag)
 	if (sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION) {
 		u32 prior_retrans = tp->retrans_out;
 
-		tcp_rack_mark_lost(sk);
+		if (tcp_rack_mark_lost(sk))
+			*ack_flag &= ~FLAG_SET_XMIT_TIMER;
 		if (prior_retrans > tp->retrans_out)
 			*ack_flag |= FLAG_LOST_RETRANS;
 	}
@@ -3516,10 +3517,8 @@ static void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
 	}
 }
 
-/* This routine deals with acks during a TLP episode.
- * We mark the end of a TLP episode on receiving TLP dupack or when
- * ack is after tlp_high_seq.
- * Ref: loss detection algorithm in draft-dukkipati-tcpm-tcp-loss-probe.
+/* This routine deals with acks during a TLP episode and ends an episode by
+ * resetting tlp_high_seq. Ref: TLP algorithm in draft-ietf-tcpm-rack
  */
 static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
 {
@@ -3528,7 +3527,10 @@ static void tcp_process_tlp_ack(struct sock *sk, u32 ack, int flag)
 	if (before(ack, tp->tlp_high_seq))
 		return;
 
-	if (flag & FLAG_DSACKING_ACK) {
+	if (!tp->tlp_retrans) {
+		/* TLP of new data has been acknowledged */
+		tp->tlp_high_seq = 0;
+	} else if (flag & FLAG_DSACKING_ACK) {
 		/* This DSACK means original and TLP probe arrived; no loss */
 		tp->tlp_high_seq = 0;
 	} else if (after(ack, tp->tlp_high_seq)) {
@@ -3687,15 +3689,16 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 
 	if (tp->tlp_high_seq)
 		tcp_process_tlp_ack(sk, ack, flag);
-	/* If needed, reset TLP/RTO timer; RACK may later override this. */
-	if (flag & FLAG_SET_XMIT_TIMER)
-		tcp_set_xmit_timer(sk);
 
 	if (tcp_ack_is_dubious(sk, flag)) {
 		is_dupack = !(flag & (FLAG_SND_UNA_ADVANCED | FLAG_NOT_DUP));
 		tcp_fastretrans_alert(sk, acked, is_dupack, &flag, &rexmit);
 	}
 
+	/* If needed, reset TLP/RTO timer when RACK doesn't set. */
+	if (flag & FLAG_SET_XMIT_TIMER)
+		tcp_set_xmit_timer(sk);
+
 	if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP))
 		sk_dst_confirm(sk);
 
@@ -4507,7 +4510,11 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
 	if (tcp_ooo_try_coalesce(sk, tp->ooo_last_skb,
 				 skb, &fragstolen)) {
 coalesce_done:
-		tcp_grow_window(sk, skb);
+		/* For non sack flows, do not grow window to force DUPACK
+		 * and trigger fast retransmit.
+		 */
+		if (tcp_is_sack(tp))
+			tcp_grow_window(sk, skb);
 		kfree_skb_partial(skb, fragstolen);
 		skb = NULL;
 		goto add_sack;
@@ -4591,7 +4598,11 @@ add_sack:
 		tcp_sack_new_ofo_skb(sk, seq, end_seq);
 end:
 	if (skb) {
-		tcp_grow_window(sk, skb);
+		/* For non sack flows, do not grow window to force DUPACK
+		 * and trigger fast retransmit.
+		 */
+		if (tcp_is_sack(tp))
+			tcp_grow_window(sk, skb);
 		skb_condense(skb);
 		skb_set_owner_r(skb, sk);
 	}
@@ -5530,6 +5541,8 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 				tcp_data_snd_check(sk);
 				if (!inet_csk_ack_scheduled(sk))
 					goto no_ack;
+			} else {
+				tcp_update_wl(tp, TCP_SKB_CB(skb)->seq);
 			}
 
 			__tcp_ack_snd_check(sk, 0);