This makes Request object takes hash, compare, free, and process functions.
With this change, the logic in networkd-queue.c can be mostly
independent of the type of the request or the object (e.g. Address) assigned
to the request, and it becomes simpler.
In most netlink handlers, we do the following,
1. decrease the message counter,
2. check the link state,
3. error handling,
4. update link state via e.g. link_check_ready().
The first two steps are mostly common, hence let's extract it.
Moreover, this is not only extracting the common logic, but provide a
strong advantage; `request_call_netlink_async()` assigns the relevant
Request object to the userdata of the netlink slot, and the request object
has full information about the message we sent. Hence, in the future,
netlink handler can print more detailed error message. E.g. when
an address is failed to configure, then currently we only show an
address is failed to configure, but with this commit, potentially we can
show which address is failed explicitly.
This does not change such error handling yet. But let's do that later.
Previously, even though all Request object are owned by Manager, they
do not have direct reference to Manager, but through Link or NetDev
object. But, as Link or NetDev can be NULL, we need to conditionalize
how to access Manager from Request with the type of the request.
This makes the way simpler, as now Request object has direct reference
to Manager.
This also rename request_drop() -> request_detach(), as in the previous
commit, the reference counter is introduced, so even if a reference of
a Request object from Manager is dropped, the object may still alive.
The naming `request_drop()` sounds the object will freed by the
function. But it may not. And `request_detach()` suggests the object
will not be managed by Manager any more, and I think it is more
appropreate.
This is just a cleanup, and should not change any behavior.
Currently, all Request object are always owned by Manager, and freed
when it is processed, especially, soon after a netlink message is sent.
So, it is not necessary to introduce the reference counter.
In a later commit, the Request object will _not_ be freed at the time
when a netlink message is sent, but assigned to the relevant netlink
slot as a userdata, and will be freed when a reply is received. So, the
owner of the Request object is changed in its lifetime. In that case, it
is convenient that the object has reference counter to avoid memleak or
double free.
Previously, when UUID is requested for DUID, then the clients are
configured in callback of bus methods.
But now, 'request queue' was implemented, so we can use it to wait until
the product UUID is obtained.
Previously, when `link_request_queue()` is called in link_request_set_link(),
`SetLinkOperation` is casted with INT_TO_PTR(), and the value is assigned to
`void *object`. However the value was read directly through the member
`SetLinkOperation set_link_operation` of the union which `object`
beloging to. Thus, read value was always 0 on big-endian systems.
Fixes configuring link issue on s390x systems.
Why is this necessary? Several examples below.
- When a route sets prefsrc, then the address must be already assigned
(see issue #19285), and also it must be ready if IPv6.
- When a route or nexthop sets gateway, then the address must be reachable.
- When a route sets nexthop ID, then the corresponding nexthop must be
assigned.
- When a route sets multipath routes on another interface, then the
interface must exist and be ready to configure.
- When configuring address, the same address must not be under removing
(see issue #18108).
Etc,. etc,...
So, this makes all requests about addresses, routes, and nethops are once
stored in the queue, and will be processed when they are ready to configure.
Fixes#18108 and #19285.
