diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2025-07-21 17:48:36 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-07-21 17:48:36 -0700 |
| commit | e8c24e23c4c9f515b02dde01de9ec2c945b2fddc (patch) | |
| tree | 3ffc1f020184b13f91b038aaa7a1a8accb8a661c /net/ipv4/tcp.c | |
| parent | 1b02c861714bf28814926d1fcb3c5594de960757 (diff) | |
| parent | 154e56a77d81ad49eb979aa64463d5fcfad51136 (diff) | |
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/20250716-net-next-mptcp-tcp_maxseg-v1-0-548d3a5666f6@kernel.org
====================
Link: https://patch.msgid.link/20250719-net-next-mptcp-tcp_maxseg-v2-0-8c910fbc5307@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 31149a0ac849..71a956fbfc55 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3751,6 +3751,19 @@ int tcp_set_window_clamp(struct sock *sk, int val) return 0; } +int tcp_sock_set_maxseg(struct sock *sk, int val) +{ + /* Values greater than interface MTU won't take effect. However + * at the point when this call is done we typically don't yet + * know which interface is going to be used + */ + if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) + return -EINVAL; + + tcp_sk(sk)->rx_opt.user_mss = val; + return 0; +} + /* * Socket option code for TCP. */ @@ -3883,15 +3896,7 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname, switch (optname) { case TCP_MAXSEG: - /* Values greater than interface MTU won't take effect. However - * at the point when this call is done we typically don't yet - * know which interface is going to be used - */ - if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) { - err = -EINVAL; - break; - } - tp->rx_opt.user_mss = val; + err = tcp_sock_set_maxseg(sk, val); break; case TCP_NODELAY: |