Jakub Kicinski
97499e2818
Matthieu Baerts says: ==================== mptcp: pm: nl: announce deny-join-id0 flag During the connection establishment, a peer can tell the other one that it cannot establish new subflows to the initial IP address and port by setting the 'C' flag [1]. Doing so makes sense when the sender is behind a strict NAT, operating behind a legacy Layer 4 load balancer, or using anycast IP address for example. When this 'C' flag is set, the path-managers must then not try to establish new subflows to the other peer's initial IP address and port. The in-kernel PM has access to this info, but the userspace PM didn't, not letting the userspace daemon able to respect the RFC8684. Here are a few fixes related to this 'C' flag (aka 'deny-join-id0'): - Patch 1: add remote_deny_join_id0 info on passive connections. A fix for v5.14. - Patch 2: let the userspace PM daemon know about the deny_join_id0 attribute, so when set, it can avoid creating new subflows to the initial IP address and port. A fix for v5.19. - Patch 3: a validation for the previous commit. - Patch 4: record the deny_join_id0 info when TFO is used. A fix for v6.2. - Patch 5: not related to deny-join-id0, but it fixes errors messages in the sockopt selftests, not to create confusions. A fix for v6.5. ==================== Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-0-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
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