This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
This also adds the ability to incorporate arrays into netlink messages
and to determine when a netlink message is too big, used by some generic
netlink protocols.
Routing Policy rule manipulates rules in the routing policy database control the
route selection algorithm.
This work supports to configure Rule
```
[RoutingPolicyRule]
TypeOfService=0x08
Table=7
From= 192.168.100.18
```
```
ip rule show
0: from all lookup local
0: from 192.168.100.18 tos 0x08 lookup 7
```
V2 changes:
1. Added logic to handle duplicate rules.
2. If rules are changed or deleted and networkd restarted
then those are deleted when networkd restarts next time
V3:
1. Add parse_fwmark_fwmask
We don't have plural in the name of any other -util files and this
inconsistency trips me up every time I try to type this file name
from memory. "formats-util" is even hard to pronounce.
On larger systems we might very well see messages with thousands of parts.
When we free them, we must avoid recursing into each part, otherwise we
very likely get stack overflows.
Fix sd_netlink_message_unref() to use an iterative approach rather than
recursion (also avoid tail-recursion in case it is not optimized by the
compiler).
Throughout the tree there's spurious use of spaces separating ++ and --
operators from their respective operands. Make ++ and -- operator
consistent with the majority of existing uses; discard the spaces.
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
By default we set as NLM_F_CREATE | NLM_F_EXCL in
sd_rtnl_message_new_link
But incase of bridge we need to set NLM_F_REQUEST | NLM_F_ACK.
If NLM_F_EXCL is set then we are unable to set the parameters. As bridge
supports setting properties after creation not during creation.
Though currently unused by us, netlink attribute types support embedding flags to indicate
if the type is encoded in network byte-order and if it is a nested attribute. Read out
these flags when parsing the message.
We will now swap the byteorder in case it is non-native when reading out integers (though
this is not needed by any of the types we currently support). We do not enforce the NESTED
flag, as the kernel gets this wrong in many cases.
Instead of representing containers as several arrays, make a new
netlink_container struct and keep one array of these structs. We
also introduce netlink_attribute structs that in the future will
hold meta-information about each atribute.
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.
In sd-netlink-message, we always guarantee that the currently selected
type-system is non-NULL. Otherwise, we would be unable to parse any types
in the current container level. Hence, this assertion must be true:
message->container_type_system[m->n_containers] != NULL
During message_new() we currently do not verify that this assertion is
true. Instead, we blindly access nl_type->type_system and use it (which
might be NULL for basic types and unions). Fix this, by explicitly
checking that the root-level type is nested.
Note that this is *not* a strict requirement of netlink, but it's a strict
requirement for all message types we currently support. Furthermore, all
the callers of message_new() already verify that only supported types are
passed, therefore, this is a pure cosmetic check. However, it might be
needed on the future, so make sure we don't trap into this once we change
the type-system.
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.
size_t is usually 64bit and int 32bit on a 64bit machine. This probably
does not matter for netlink message sizes, but nevertheless, avoid
hard-coding it anywhere.
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.
Lennart Poettering