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.
Yu Watanabe