From: Willem de Bruijn <will...@google.com> 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 <will...@google.com> --- net/ipv4/tcp_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 5c46bc4c7e8d..42abc9bd687a 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2053,7 +2053,7 @@ static bool tcp_can_coalesce_send_queue_head(struct sock *sk, int len) 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; @@ -2170,6 +2170,7 @@ 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 { -- 2.23.0.187.g17f5b7556c-goog
