[v1] mptcp: getsockopt(SO_KEEPALIVE) and TCP_KEEP* sockopts

[PATCH mptcp-net 0/2] mptcp: getsockopt(SO_KEEPALIVE) and TCP_KEEP* sockopts

Matthieu Baerts (NGI0) posted 2 patches 8 months, 1 week ago

Diff against v2
Download series mbox

Patches applied successfully (tree, apply log)
git fetch https://github.com/multipath-tcp/mptcp_net-next tags/patchew/20240508-mptcp-tcp-keepalive-sockopts-v1-0-fdf7e03e14c4@kernel.org

There is a newer version of this series

net/mptcp/protocol.h |  3 +++
net/mptcp/sockopt.c  | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 60 insertions(+), 2 deletions(-)

Expand all Fold all

[PATCH mptcp-net 0/2] mptcp: getsockopt(SO_KEEPALIVE) and TCP_KEEP* sockopts

Posted by Matthieu Baerts (NGI0) 8 months, 1 week ago

This is linked to a discussion we had a few weeks ago: not supporting
TCP_KEEP* socket options is preventing MPTCP to be used in some apps or
libraries like it was the case in GoLang recently.

Supporting them is not difficult, it should have probably done before,
when SO_KEEPALIVE support has been added. Supporting them is easy and
isolated from the rest, it sounds safe enough to add a Fixes tag, and
check with the stable team to backport them. I understand it can be a
bit controversial, but it would unnecessary delay (1 or 2 years?) some
deployments, for something that simple.

While at it, getsockopt(SO_KEEPALIVE) is now returning the expected
value.

The manipulation of these different socket options can be verified with
this simple packetdrill test:

  --tolerance_usecs=100000
  `../common/defaults.sh`

  0.0    socket(..., SOCK_STREAM, IPPROTO_MPTCP) = 3
  +0     setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
  +0     bind(3, ..., ...) = 0
  +0     listen(3, 1) = 0

  +0       <  S   0:0(0)         win 8000  <mss 1024, sackOK, nop, nop, nop, wscale 0, mpcapable v1 flags[flag_h] nokey>
  +0       >  S.  0:0(0)  ack 1            <mss 1460, nop, nop, sackOK, nop, wscale 8, mpcapable v1 flags[flag_h] key[skey]>
  +0.01    <   .  1:1(0)  ack 1  win 8000                                             <mpcapable v1 flags[flag_h] key[ckey=2, skey]>
  +0     accept(3, ..., ...) = 4

  // Set and check the different Keep-Alive options.
  +0     getsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [0], [4]) = 0
  +0     setsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
  +0     getsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], [4]) = 0

  +0     getsockopt(4, SOL_TCP, TCP_KEEPIDLE, [7200], [4]) = 0
  +0     setsockopt(4, SOL_TCP, TCP_KEEPIDLE, [7200], 4) = 0
  +0     getsockopt(4, SOL_TCP, TCP_KEEPIDLE, [7200], [4]) = 0

  +0     getsockopt(4, SOL_TCP, TCP_KEEPINTVL, [75], [4]) = 0
  +0     setsockopt(4, SOL_TCP, TCP_KEEPINTVL, [10], 4) = 0
  +0     getsockopt(4, SOL_TCP, TCP_KEEPINTVL, [10], [4]) = 0

  +0     getsockopt(4, SOL_TCP, TCP_KEEPCNT, [9], [4]) = 0
  +0     setsockopt(4, SOL_TCP, TCP_KEEPCNT, [2], 4) = 0
  +0     getsockopt(4, SOL_TCP, TCP_KEEPCNT, [2], [4]) = 0

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Matthieu Baerts (NGI0) (2):
      mptcp: SO_KEEPALIVE: fix getsockopt support
      mptcp: fix full TCP keep-alive support

 net/mptcp/protocol.h |  3 +++
 net/mptcp/sockopt.c  | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 60 insertions(+), 2 deletions(-)
---
base-commit: a64044939fd33676d7098eb08397e65e83d278ed
change-id: 20240507-mptcp-tcp-keepalive-sockopts-546d3b1f3256

Best regards,
-- 
Matthieu Baerts (NGI0) <matttbe@kernel.org>