tools: ynl: Fix spelling mistake "Constructred" -> "Constructed"

There is a spelling mistake in an error message. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20240308084458.2045266-1-colin.i.king@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: check for overflow of constructed messages

Donald points out that we don't check for overflows.
Stash the length of the message on nlmsg_pid (nlmsg_seq would
do as well). This allows the attribute helpers to remain
self-contained (no extra arguments). Also let the put
helpers continue to return nothing. The error is checked
only in (newly introduced) ynl_msg_end().

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20240305185000.964773-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: use MSG_DONTWAIT for getting notifications

To stick to libmnl wrappers in the past we had to use poll()
to check if there are any outstanding notifications on the socket.
This is no longer necessary, we can use MSG_DONTWAIT.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-16-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: remove the libmnl dependency

We don't use libmnl any more.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-15-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: stop using mnl socket helpers

Most libmnl socket helpers can be replaced by direct calls to
the underlying libc API. We need portid, the netlink manpage
suggests we bind() address of zero.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-14-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: switch away from MNL_CB_*

Create a local version of the MNL_CB_* parser control values.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-13-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: switch away from mnl_cb_t

All YNL parsing callbacks take struct ynl_parse_arg as the argument.
Make that official by using a local callback type instead of mnl_cb_t.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-12-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: stop using mnl_cb_run2()

There's only one set of callbacks in YNL, for netlink control
messages, and most of them are trivial. So implement the message
walking directly without depending on mnl_cb_run2().

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-11-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: use ynl_sock_read_msgs() for ACK handling

ynl_recv_ack() is simple and it's the only user of mnl_cb_run().
Now that ynl_sock_read_msgs() exists it's actually less code
to use ynl_sock_read_msgs() instead of being special.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-10-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: wrap recv() + mnl_cb_run2() into a single helper

All callers to mnl_cb_run2() call mnl_socket_recvfrom() right before.
Wrap the two in a helper, take typed arguments (struct ynl_parse_arg),
instead of hoping that all callers remember that parser error handling
requires yarg.

In case of ynl_sock_read_family() we will no longer check for kernel
returning no data, but that would be a kernel bug, not worth complicating
the code to catch this. Calling mnl_cb_run2() on an empty buffer
is legal and results in STOP (1).

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl-gen: remove unused parse code

Commit f2ba1e5e2208 ("tools: ynl-gen: stop generating common notification handlers")
removed the last caller of the parse_cb_run() helper.
We no longer need to export ynl_cb_array.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-8-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: make yarg the first member of struct ynl_dump_state

All YNL parsing code expects a pointer to struct ynl_parse_arg AKA yarg.
For dump was pass in struct ynl_dump_state, which works fine, because
struct ynl_dump_state and struct ynl_parse_arg have identical layout
for the members that matter.. but it's a bit hacky.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: create local nlmsg access helpers

Create helpers for accessing payloads of struct nlmsg.
Use them instead of the libmnl ones.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: create local for_each helpers

Create ynl_attr_for_each*() iteration helpers.
Use them instead of the mnl ones.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: create local attribute helpers

Don't use mnl attr helpers, we're trying to remove the libmnl
dependency. Create both signed and unsigned helpers, libmnl
had unsigned helpers, so code generator no longer needs
the mnl_type() hack.

The new helpers are written from first principles, but are
hopefully not too buggy.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: fix handling of multiple mcast groups

We never increment the group number iterator, so all groups
get recorded into index 0 of the mcast_groups[] array.

As a result YNL can only handle using the last group.
For example using the "netdev" sample on kernel with
page pool commands results in:

$ ./samples/netdev
YNL: Multicast group 'mgmt' not found

Most families have only one multicast group, so this hasn't
been noticed. Plus perhaps developers usually test the last
group which would have worked.

Fixes: 86878f14d71a ("tools: ynl: user space helpers")
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240226214019.1255242-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: don't leak mcast_groups on init error

Make sure to free the already-parsed mcast_groups if
we don't get an ack from the kernel when reading family info.
This is part of the ynl_sock_create() error path, so we won't
get a call to ynl_sock_destroy() to free them later.

Fixes: 86878f14d71a ("tools: ynl: user space helpers")
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240220161112.2735195-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: make sure we always pass yarg to mnl_cb_run

There is one common error handler in ynl - ynl_cb_error().
It expects priv to be a pointer to struct ynl_parse_arg AKA yarg.
To avoid potential crashes if we encounter a stray NLMSG_ERROR
always pass yarg as priv (or a struct which has it as the first
member).

ynl_cb_null() has a similar problem directly - it expects yarg
but priv passed by the caller is ys.

Found by code inspection.

Fixes: 86878f14d71a ("tools: ynl: user space helpers")
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240220161112.2735195-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl-gen: support fixed headers in genetlink

Support genetlink families using simple fixed headers.
Assume fixed header is identical for all ops of the family for now.

Fixed headers are added to the request and reply structs as a _hdr
member, and copied to/from netlink messages appropriately.

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20231213231432.2944749-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: use strerror() if no extack of note provided

If kernel didn't give use any meaningful error - print
a strerror() to the ynl error message.

Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20231202211310.342716-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl-gen: introduce support for bitfield32 attribute type

Introduce support for attribute type bitfield32.
Note that since the generated code works with struct nla_bitfield32,
the generator adds netlink.h to the list of includes for userspace
headers in case any bitfield32 is present.

Note that this is added only to genetlink-legacy scheme as requested
by Jakub Kicinski.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231021112711.660606-3-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

netlink: specs: add support for auto-sized scalars

Support uint / sint types in specs and YNL.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools: ynl: user space helpers

Add "fixed" part of the user space Netlink Spec-based library.
This will get linked with the protocol implementations to form
a full API.

Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>