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| author |   Jakub Kicinski <kuba@kernel.org> | 2022-08-25 20:09:31 -0700 |
|---|---|---|
| committer |   Paolo Abeni <pabeni@redhat.com> | 2022-08-30 12:20:43 +0200 |
| commit | 690252f19f0e486abb8590b3a7a03d4e065d93d4 (patch) | |
| tree | a656cf7a2cec54ed3ff0ff28df4c9176c0228763 /Documentation/userspace-api/netlink/intro.rst | |
| parent | netlink: factor out extack composition (diff) | |
| download | linux-dev-690252f19f0e486abb8590b3a7a03d4e065d93d4.tar.xz linux-dev-690252f19f0e486abb8590b3a7a03d4e065d93d4.zip | |
netlink: add support for ext_ack missing attributes
There is currently no way to report via extack in a structured way
that an attribute is missing. This leads to families resorting to
string messages.
Add a pair of attributes - @offset and @type for machine-readable
way of reporting missing attributes. The @offset points to the
nest which should have contained the attribute, @type is the
expected nla_type. The offset will be skipped if the attribute
is missing at the message level rather than inside a nest.
User space should be able to figure out which attribute enum
(AKA attribute space AKA attribute set) the nest pointed to by
@offset is using.
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'Documentation/userspace-api/netlink/intro.rst')
| -rw-r--r-- | Documentation/userspace-api/netlink/intro.rst | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/userspace-api/netlink/intro.rst b/Documentation/userspace-api/netlink/intro.rst index 94337f79e077..8f1220756412 100644 --- a/Documentation/userspace-api/netlink/intro.rst +++ b/Documentation/userspace-api/netlink/intro.rst @@ -359,8 +359,8 @@ compatibility this feature has to be explicitly enabled by setting the ``NETLINK_EXT_ACK`` setsockopt() to ``1``. Types of extended ack attributes are defined in enum nlmsgerr_attrs. -The two most commonly used attributes are ``NLMSGERR_ATTR_MSG`` -and ``NLMSGERR_ATTR_OFFS``. +The most commonly used attributes are ``NLMSGERR_ATTR_MSG``, +``NLMSGERR_ATTR_OFFS`` and ``NLMSGERR_ATTR_MISS_*``. ``NLMSGERR_ATTR_MSG`` carries a message in English describing the encountered problem. These messages are far more detailed @@ -368,6 +368,9 @@ than what can be expressed thru standard UNIX error codes. ``NLMSGERR_ATTR_OFFS`` points to the attribute which caused the problem. +``NLMSGERR_ATTR_MISS_TYPE`` and ``NLMSGERR_ATTR_MISS_NEST`` +inform about a missing attribute. + Extended ACKs can be reported on errors as well as in case of success. The latter should be treated as a warning. |