Switch platform caching implementation. Instead of caching libnl
objects, cache our own types.
Don't remove yet the now obsolete functions.
Advantage:
* Performance
- as we now cache our native NMPlatformObject instances, we no longer
have to convert libnl objects every time we access the platform
cache.
- for most cases, access is now O(1) because we can lookup the object
in a hash table. Note that ip4_address_get_all() still has to
create a copy of the result (O(n)), but as the caller is about to
use those elements, he cannot do better then O(n) anyway.
* We cache our own native types and have full control over them. We
cannot extend the libnl objects, which has many short-commings:
- _rtnl_addr_hack_lifetimes_rel_to_abs() to convert the timestamps
to absolute values (and back).
- hack_empty_master_iff_lower_up() would modify the internal flag,
but it looses the original value. That means, we can only hack
the state before putting a link into the cache, but we cannot revert
that change, when a slave in the cache changes state.
That was previously solved by always refetching the master when
a slave changed. Now we can re-evaluate the connected state
(DELAYED_ACTION_TYPE_MASTER_CONNECTED).
- we implement functions like equality, to-string as most suitable
for us. Before we needed hacks like nm_nl_object_diff(),
nm_nl_cache_search(), route_search_cache().
- we can extend our objects with exactly those properties we care,
and possibly additional properties that are not representable in
the libnl objects.
- we no longer cache RTM_F_CLONED routes and they get rejected early
on as we receive them.
- In the future, maybe it'd be interesting the make platform objects
immutable (and ref-counted) and expose them directly.
* Previous implementation did not order the refresh of objects but
called check_cache_items(). Now, those actions are delayed and
combined in an attempt to reduce the overall number of reloads.
Realize how expensive a check_cache_items() for addresses and routes
was: it would iterate all addresses/routes and call refresh_object().
The latter obtains a full dump of *all* objects again, and ignores
all but the needle.
Note that we probably still schedule some delayed actions that
are not needed.
Later we can optimize that further (related bug bgo #747985).
While some of these points could also have been implemented with
caching of libnl objects, that would have become hard to maintain.
https://bugzilla.gnome.org/show_bug.cgi?id=747981
NMPObject is a simple "object" implemenation around NMPlatformObject.
They are ref-counted and have a class-pointer. Several basic functions
like equality, hash, to-string are implemented.
NMPCache is can be used to store the NMPObject. Objects are indexed
via their primary id, but there is also multi-lookup via NMCacheId
and NMMultiIndex.
Part of the implementation is inside "nm-linux-platform.c",
because it depends on utility functions from there.
Cache the scope as part of the NMPlatformIP4Route and
no longer read it from libnl object when needed. Later
there will be no more libnl objects around, and we need
to scope when deleting an IPv4 route.
warning: function declaration isn’t a prototype [-Wstrict-prototypes]
In C function() and function(void) are two different prototypes (as opposed to
C++).
function() accepts an arbitrary number of arguments
function(void) accepts zero arguments
There is no general purpose file for platform utilities.
We only have nm-platform.h, which contains (mostly) functions
that operate on a NMPlatform instance (and that can be mocked
using NMFakePlatform).
Add a new file for independent utility functions. nm-platform-utils.c
should not call into functions having a NMPlatform instance, to
have them independent from platform caching and the platform
singleton.
nm_platform_query_devices() would raise an 'added' signal
for all its links. That is bad style because it could
confuse other listeners for platform signals which don't
expect such artificial change signals.
The public API of NMPlatform already gives NMManager the ability
to 'pull' all the links and iterate them itself.
Before, nm_platform_query_devices() would also initialize udev
devices, so there was a more compelling reason for this function.
We already populate the netlink cache in constructed(). No need
to wait with udev devices until nm_platform_query_devices(). Just
do it right away.
Add a hack to keep 'lo' default-unmanaged. Now that we load
udev devices earlier, we end up clearing the default-unmanged
flag on 'lo', which has bad consequences.
We don't want error logging for nm_platform_link_add() which
tries to load the bonding module. Later we will run tests as non-root,
where modprobe will fail. Logging an error would break the tests.
Support accepting more then one signal at a time.
It is to be expected, that one change in platform raises
several signals. Extend the assertion helpers to express
that.
