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: 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: 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-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 ARRAY_SIZE() helper

libc doesn't have an ARRAY_SIZE() create one locally.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-6-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: give up on libmnl for auto-ints

The temporary auto-int helpers are not really correct.
We can't treat signed and unsigned ints the same when
determining whether we need full 8B. I realized this
before sending the patch to add support in libmnl.
Unfortunately, that patch has not been merged,
so time to fix our local helpers. Use the mnl* name
for now, subsequent patches will address that.

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools: ynl: move private definitions to a separate header

ynl.h has a growing amount of "internal" stuff, which may confuse
users who try to take a look at the external API. Currently the
internals are at the bottom of the file with a banner in between,
but this arrangement makes it hard to add external APIs / inline
helpers which need internal definitions.

Move internals to a separate header.

Link: https://lore.kernel.org/r/20231202211225.342466-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>