From: Willem de Bruijn willemb@google.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@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 --- 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 {