tcp: inherit timestamp on mtu probe
authorWillem de Bruijn <willemb@google.com>
Tue, 27 Aug 2019 19:09:33 +0000 (15:09 -0400)
committerDavid S. Miller <davem@davemloft.net>
Wed, 28 Aug 2019 22:56:28 +0000 (15:56 -0700)
commit888a5c53c0d8be6e98bc85b677f179f77a647873
treed882b9205799014bac650960277f88a76147f400
parentdbf47a2a094edf58983265e323ca4bdcdb58b5ee
tcp: inherit timestamp on mtu probe

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>
net/ipv4/tcp_output.c