linux-stable.git/Documentation/netlink, branch linux-6.16.y

mptcp: pm: nl: announce deny-join-id0 flag

2025-09-25T09:16:53+00:00

commit 2293c57484ae64c9a3c847c8807db8c26a3a4d41 upstream.

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
[ Conflicts in mptcp_pm.yaml, because the indentation has been modified
in commit ec362192aa9e ("netlink: specs: fix up indentation errors"),
which is not in this version. Applying the same modifications, but at
a different level. ]
Signed-off-by: Matthieu Baerts (NGI0)
Signed-off-by: Greg Kroah-Hartman

doc/netlink: Fix typos in operation attributes

2025-09-25T09:16:44+00:00

[ Upstream commit 109f8b51543d106aee50dfe911f439e43fb30c7a ]

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 
Signed-off-by: Sasha Levin

netlink: specs: mptcp: fix if-idx attribute type

2025-09-19T14:37:30+00:00

commit 7094b84863e5832cb1cd9c4b9d648904775b6bd9 upstream.

This attribute is used as a signed number in the code in pm_netlink.c:

  nla_put_s32(skb, MPTCP_ATTR_IF_IDX, ssk->sk_bound_dev_if))

The specs should then reflect that. Note that other 'if-idx' attributes
from the same .yaml file use a signed number as well.

Fixes: bc8aeb2045e2 ("Documentation: netlink: add a YAML spec for mptcp")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20250908-net-mptcp-misc-fixes-6-17-rc5-v1-1-5f2168a66079@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

netlink: specs: ethtool: fix module EEPROM input/output arguments

2025-08-15T14:39:24+00:00

[ Upstream commit 01051012887329ea78eaca19b1d2eac4c9f601b5 ]

Module (SFP) eeprom GET has a lot of input params, they are all
mistakenly listed as output in the spec. Looks like kernel doesn't
output them at all. Correct what are the inputs and what the outputs.

Reported-by: Duo Yi 
Fixes: a353318ebf24 ("tools: ynl: populate most of the ethtool spec")
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250730172137.1322351-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ovpn: reject unexpected netlink attributes

2025-07-16T09:51:30+00:00

Netlink ops do not expect all attributes to be always set, however
this condition is not explicitly coded any where, leading the user
to believe that all sent attributes are somewhat processed.

Fix this behaviour by introducing explicit checks.

For CMD_OVPN_PEER_GET and CMD_OVPN_KEY_GET directly open-code the
needed condition in the related ops handlers.
While for all other ops use attribute subsets in the ovpn.yaml spec file.

Fixes: b7a63391aa98 ("ovpn: add basic netlink support")
Reported-by: Ralf Lici 
Closes: https://github.com/OpenVPN/ovpn-net-next/issues/19
Signed-off-by: Antonio Quartulli

netlink: specs: enforce strict naming of properties

2025-06-25T22:36:28+00:00

Add a regexp to make sure all names which may end up being visible
to the user consist of lower case characters, numbers and dashes.
Underscores keep sneaking into the specs, which is not visible
in the C code but makes the Python and alike inconsistent.

Note that starting with a number is okay, as in C the full
name will include the family name.

For legacy families we can't enforce the naming in the family
name or the multicast group names, as these are part of the
binary uAPI of the kernel.

For classic netlink we need to allow capital letters in names
of struct members. TC has some structs with capitalized members.

Reviewed-by: Donald Hunter 
Link: https://patch.msgid.link/20250624211002.3475021-11-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netlink: specs: tc: replace underscores with dashes in names

2025-06-25T22:36:28+00:00

We're trying to add a strict regexp for the name format in the spec.
Underscores will not be allowed, dashes should be used instead.
This makes no difference to C (codegen, if used, replaces special
chars in names) but it gives more uniform naming in Python.

Fixes: a1bcfde83669 ("doc/netlink/specs: Add a spec for tc")
Reviewed-by: Donald Hunter 
Link: https://patch.msgid.link/20250624211002.3475021-10-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netlink: specs: rt-link: replace underscores with dashes in names

2025-06-25T22:36:28+00:00

We're trying to add a strict regexp for the name format in the spec.
Underscores will not be allowed, dashes should be used instead.
This makes no difference to C (codegen, if used, replaces special
chars in names) but it gives more uniform naming in Python.

Fixes: b2f63d904e72 ("doc/netlink: Add spec for rt link messages")
Reviewed-by: Jacob Keller 
Reviewed-by: Donald Hunter 
Link: https://patch.msgid.link/20250624211002.3475021-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netlink: specs: mptcp: replace underscores with dashes in names

2025-06-25T22:36:28+00:00

We're trying to add a strict regexp for the name format in the spec.
Underscores will not be allowed, dashes should be used instead.
This makes no difference to C (codegen, if used, replaces special
chars in names) but it gives more uniform naming in Python.

Fixes: bc8aeb2045e2 ("Documentation: netlink: add a YAML spec for mptcp")
Reviewed-by: Davide Caratti 
Reviewed-by: Donald Hunter 
Reviewed-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20250624211002.3475021-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski

netlink: specs: ovs_flow: replace underscores with dashes in names

2025-06-25T22:36:28+00:00

We're trying to add a strict regexp for the name format in the spec.
Underscores will not be allowed, dashes should be used instead.
This makes no difference to C (codegen, if used, replaces special
chars in names) but it gives more uniform naming in Python.

Fixes: 93b230b549bc ("netlink: specs: add ynl spec for ovs_flow")
Reviewed-by: Donald Hunter 
Reviewed-by: Ilya Maximets 
Reviewed-by: Eelco Chaudron 
Link: https://patch.msgid.link/20250624211002.3475021-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski