From 2293c57484ae64c9a3c847c8807db8c26a3a4d41 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 12 Sep 2025 14:52:21 +0200 Subject: 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. The RFC8684 [1] is strict about that: (...) therefore the receiver MUST NOT try to open any additional subflows toward this address and port. So it is important to tell the userspace about that as it is responsible for the respect of this flag. When a new connection is created and established, the Netlink events now contain the existing but not currently used 'flags' attribute. When MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows to the initial IP address and port -- info that are also part of the event -- can be established. Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1] Fixes: 702c2f646d42 ("mptcp: netlink: allow userspace-driven subflow establishment") Reported-by: Marek Majkowski Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532 Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40171884ade8@kernel.org Signed-off-by: Jakub Kicinski --- Documentation/netlink/specs/mptcp_pm.yaml | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml index d15335684ec3..d1b4829b580a 100644 --- a/Documentation/netlink/specs/mptcp_pm.yaml +++ b/Documentation/netlink/specs/mptcp_pm.yaml @@ -28,13 +28,13 @@ definitions: traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side. + dport, server-side, [flags]. - name: established doc: >- A MPTCP connection is established (can start new subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side. + dport, server-side, [flags]. - name: closed doc: >- -- cgit v1.2.3 From 109f8b51543d106aee50dfe911f439e43fb30c7a Mon Sep 17 00:00:00 2001 From: "Remy D. Farley" Date: Sat, 13 Sep 2025 14:05:28 +0000 Subject: doc/netlink: Fix typos in operation attributes I'm trying to generate Rust bindings for netlink using the yaml spec. It looks like there's a typo in conntrack spec: attribute set conntrack-attrs defines attributes "counters-{orig,reply}" (plural), while get operation references "counter-{orig,reply}" (singular). The latter should be fixed, as it denotes multiple counters (packet and byte). The corresonding C define is CTA_COUNTERS_ORIG. Also, dump request references "nfgen-family" attribute, which neither exists in conntrack-attrs attrset nor ctattr_type enum. There's member of nfgenmsg struct with the same name, which is where family value is actually taken from. > static int ctnetlink_dump_exp_ct(struct net *net, struct sock *ctnl, > struct sk_buff *skb, > const struct nlmsghdr *nlh, > const struct nlattr * const cda[], > struct netlink_ext_ack *extack) > { > int err; > struct nfgenmsg *nfmsg = nlmsg_data(nlh); > u_int8_t u3 = nfmsg->nfgen_family; ^^^^^^^^^^^^ Signed-off-by: Remy D. Farley Fixes: 23fc9311a526 ("netlink: specs: add conntrack dump and stats dump support") Link: https://patch.msgid.link/20250913140515.1132886-1-one-d-wide@protonmail.com Signed-off-by: Jakub Kicinski --- Documentation/netlink/specs/conntrack.yaml | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/netlink/specs/conntrack.yaml b/Documentation/netlink/specs/conntrack.yaml index c6832633ab7b..591e22a2ee43 100644 --- a/Documentation/netlink/specs/conntrack.yaml +++ b/Documentation/netlink/specs/conntrack.yaml @@ -575,8 +575,8 @@ operations: - nat-dst - timeout - mark - - counter-orig - - counter-reply + - counters-orig + - counters-reply - use - id - nat-dst @@ -591,7 +591,6 @@ operations: request: value: 0x101 attributes: - - nfgen-family - mark - filter - status @@ -608,8 +607,8 @@ operations: - nat-dst - timeout - mark - - counter-orig - - counter-reply + - counters-orig + - counters-reply - use - id - nat-dst -- cgit v1.2.3