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authorWillem de Bruijn <willemb@google.com>2019-08-27 15:09:33 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-09-10 10:31:04 +0100
commit217fc82985419ffb4ff8bdc5b4617b42d8f8c020 (patch)
parent9e208ccf32eaf35738b342ee9dd491a99f8ac8e2 (diff)
tcp: inherit timestamp on mtu probe
[ 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@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 9ddb05b98312..2e77e78ab226 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1943,7 +1943,7 @@ static bool tcp_can_coalesce_send_queue_head(struct sock *sk, int len)
if (len <= skb->len)
- if (unlikely(TCP_SKB_CB(skb)->eor))
+ if (unlikely(TCP_SKB_CB(skb)->eor) || tcp_has_tx_tstamp(skb))
return false;
len -= skb->len;
@@ -2066,6 +2066,7 @@ 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 {