Merge branch 'mptcp-add-tcp_maxseg-sockopt-support'

Matthieu Baerts says:

====================
mptcp: add TCP_MAXSEG sockopt support

The TCP_MAXSEG socket option was not supported by MPTCP, mainly because
it has never been requested before. But there are still valid use-cases,
e.g. with HAProxy.

- Patch 1 is a small cleanup patch in the MPTCP sockopt file.

- Patch 2 expose some code from TCP, to avoid duplicating it in MPTCP.

- Patch 3 adds TCP_MAXSEG sockopt support in MPTCP.

- Patch 4 is not related to the others, it fixes a typo in a comment.

Note that the new TCP_MAXSEG sockopt support has been validated by a new
packetdrill script on the MPTCP CI:

  https://github.com/multipath-tcp/packetdrill/pull/161

v1: https://lore.kernel.org/[email protected]
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 6ec245fd2778..1a32edf6f343 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -326,6 +326,7 @@ struct mptcp_sock {
 	int		keepalive_cnt;
 	int		keepalive_idle;
 	int		keepalive_intvl;
+	int		maxseg;
 	struct work_struct work;
 	struct sk_buff  *ooo_last_skb;
 	struct rb_root  out_of_order_queue;