3 files changed, 19 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index b91370f61be6..6db10228113f 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -552,6 +552,8 @@ void tcp_send_ack(struct sock *sk);
 void tcp_send_delayed_ack(struct sock *sk);
 void tcp_send_loss_probe(struct sock *sk);
 bool tcp_schedule_loss_probe(struct sock *sk);
+void tcp_skb_collapse_tstamp(struct sk_buff *skb,
+			     const struct sk_buff *next_skb);
 
 /* tcp_input.c */
 void tcp_resume_early_retransmit(struct sock *sk);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 0edb07185c25..c124c3c12f7c 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1309,6 +1309,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
 	if (skb == tcp_highest_sack(sk))
 		tcp_advance_highest_sack(sk, skb);
 
+	tcp_skb_collapse_tstamp(prev, skb);
 	tcp_unlink_write_queue(skb, sk);
 	sk_wmem_free_skb(sk, skb);
 
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 7d2dc015cd19..441ae9da3a23 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2441,6 +2441,20 @@ u32 __tcp_select_window(struct sock *sk)
 	return window;
 }
 
+void tcp_skb_collapse_tstamp(struct sk_buff *skb,
+			     const struct sk_buff *next_skb)
+{
+	const struct skb_shared_info *next_shinfo = skb_shinfo(next_skb);
+	u8 tsflags = next_shinfo->tx_flags & SKBTX_ANY_TSTAMP;
+
+	if (unlikely(tsflags)) {
+		struct skb_shared_info *shinfo = skb_shinfo(skb);
+
+		shinfo->tx_flags |= tsflags;
+		shinfo->tskey = next_shinfo->tskey;
+	}
+}
+
 /* Collapses two adjacent SKB's during retransmission. */
 static void tcp_collapse_retrans(struct sock *sk, struct sk_buff *skb)
 {
@@ -2484,6 +2498,8 @@ static void tcp_collapse_retrans(struct sock *sk, struct sk_buff *skb)
 
 	tcp_adjust_pcount(sk, next_skb, tcp_skb_pcount(next_skb));
 
+	tcp_skb_collapse_tstamp(skb, next_skb);
+
 	sk_wmem_free_skb(sk, next_skb);
 }