This way we do not rely on the size MAX* constants from the kernel headers, as these will
be out-of-sync in case we have old headers and new defines in missing.h.
The kernel bonding layer allows passing an array of ARP IP targets as
bond-configuration. Due to the weird implementation of arrays in netlink
(which we haven't figure out a generic way to support, yet), we usually
hard-code the supported array-sizes. However, this should not be exported
from sd-netlink.
Instead, make sure the caller just uses it's current hack of enumerating
the types, and the sd-netlink core will have it's own list of supported
array-sizes (to be removed in future extensions, btw!). If either does not
match, we will just return a normal error.
Note that we provide 2 constants for ARP_IP_TARGETS_MAX now. However, both
have very different reasons:
- the constant in netdev-bond.c is used to warn the user that the given
number of targets might not be supported by the kernel (even though the
kernel might increase that number at _any_ time)
- the constant in sd-netlink is solely used due to us missing a proper
array implementation. Once that's supported in the type-system, it can
be removed without notice
Last but not least, this patch turns the log_error() into a log_warning().
Given that the previous condition was off-by-one, anyway, it never hit at
the right time. Thus, it was probably of no real use.
Explicitly export the root type-system to the type-system callers. This
avoids treating NULL as root, which for one really looks backwards (NULL
is usually a leaf, not root), and secondly prevents us from properly
debugging calling into non-nested types.
Also rename the root to "type_system_root". Once we support more than
rtnl, well will have to revisit that, anyway.
Empty type-systems are just fine. Avoid the nasty hack in
union-type-systems that treat empty type-systems as invalid. Instead check
for the actual types-array and make sure it's non-NULL (which is even true
for empty type-systems, due to "empty_types" array).
The NETLINK_TYPE_META pseudo-type is actually equivalent to an empty
nested type. Drop it and define an empty type-system instead.
This also has the nice side-effect that m->container_type_system[0] is
never NULL (which has really nasty side-effects if you try to read
attributes).
Right now we store the maximum type-ID of a type-system. This prevents us
from creating empty type-systems. Store the "count" instead, which should
be treated as max+1.
Note that type_system_union_protocol_get_type_system() currently has a
nasty hack to treat empty type-systems as invalid. This might need some
modification later on as well.
Same as NLType, move NLTypeSystem into netlink-types.c and hide it from
the outside. Provide an accessor function for the 'max' field that is used
to allocate suitable array sizes.
Note that this will probably be removed later on, anyway. Once we support
bigger type-systems, it just seems impractical to allocate such big arrays
for each container entry. An RBTree would probably do just fine.
If we extend NLType to support arrays and further extended types, we
really want to avoid hard-coding the type-layout outside of
netlink-types.c. We already avoid accessing nl_type->type_system outside
of netlink-types.c, extend this to also avoid accessing any other fields.
Provide accessor functions for nl_type->type and nl_type->size and then
move NLType away from the type-system header.
With this in place, follow-up patches can safely turn "type_system" and
"type_system_union" into a real "union { }", and then add another type for
arrays.
Make sure we never access type->type_system or type->type_system_union
directly. This is an implementation detail of the type-system and we
should always use the accessors. Right now, they only exist for 2-level
accesses (type-system to type-system). This patch introduces the 1-level
accessors (type to type-system) and makes use of it.
This patch makes sure the proper assertions are in place, so we never
accidentally access sub-type-systems for non-nested/union types.
Note that this places hard-asserts on the accessors. This should be fine,
as we expect callers to only access sub type-systems if they *know*
they're dealing with nested types.
The NLA_ names are used to name real datatypes we extract out of netlink
messages. The kernel has an internal enum with the same names
(NLA_foobar), which is *NOT* binary compatible to our types. Furthermore,
we support a different set of types than the kernel (as we try to treat
some kernel peculiarities as our own types to simplify the API).
Rename NLA_ to NETLINK_TYPE_ to make clear that this is our own set of
types.
Daniel Mack