From: Matthieu Baerts (NGI0) Date: Fri, 12 Sep 2025 12:52:20 +0000 (+0200) Subject: mptcp: set remote_deny_join_id0 on SYN recv X-Git-Tag: v6.17-rc7~18^2~19^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=96939cec994070aa5df852c10fad5fc303a97ea3;p=thirdparty%2Fkernel%2Fstable.git mptcp: set remote_deny_join_id0 on SYN recv When a SYN containing the 'C' flag (deny join id0) was received, this piece of information was not propagated to the path-manager. Even if this flag is mainly set on the server side, a client can also tell the server it cannot try to establish new subflows to the client's initial IP address and port. The server's PM should then record such info when received, and before sending events about the new connection. Fixes: df377be38725 ("mptcp: add deny_join_id0 in mptcp_options_received") Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-1-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 3f1b62a9fe889..f31a3a79531a2 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -883,6 +883,10 @@ create_child: ctx->subflow_id = 1; owner = mptcp_sk(ctx->conn); + + if (mp_opt.deny_join_id0) + WRITE_ONCE(owner->pm.remote_deny_join_id0, true); + mptcp_pm_new_connection(owner, child, 1); /* with OoO packets we can reach here without ingress