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Message-Id: <20190908121127.673678005@linuxfoundation.org>
Date: Sun, 8 Sep 2019 13:41:30 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Willem de Bruijn <willemb@...gle.com>,
Eric Dumazet <edumazet@...gle.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.19 06/57] tcp: inherit timestamp on mtu probe
From: Willem de Bruijn <willemb@...gle.com>
[ Upstream commit 888a5c53c0d8be6e98bc85b677f179f77a647873 ]
TCP associates tx timestamp requests with a byte in the bytestream.
If merging skbs in tcp_mtu_probe, migrate the tstamp request.
Similar to MSG_EOR, do not allow moving a timestamp from any segment
in the probe but the last. This to avoid merging multiple timestamps.
Tested with the packetdrill script at
https://github.com/wdebruij/packetdrill/commits/mtu_probe-1
Link: http://patchwork.ozlabs.org/patch/1143278/#2232897
Fixes: 4ed2d765dfac ("net-timestamp: TCP timestamping")
Signed-off-by: Willem de Bruijn <willemb@...gle.com>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
net/ipv4/tcp_output.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2046,7 +2046,7 @@ static bool tcp_can_coalesce_send_queue_
if (len <= skb->len)
break;
- if (unlikely(TCP_SKB_CB(skb)->eor))
+ if (unlikely(TCP_SKB_CB(skb)->eor) || tcp_has_tx_tstamp(skb))
return false;
len -= skb->len;
@@ -2162,6 +2162,7 @@ static int tcp_mtu_probe(struct sock *sk
* we need to propagate it to the new skb.
*/
TCP_SKB_CB(nskb)->eor = TCP_SKB_CB(skb)->eor;
+ tcp_skb_collapse_tstamp(nskb, skb);
tcp_unlink_write_queue(skb, sk);
sk_wmem_free_skb(sk, skb);
} else {
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