_idxcache_update() may remove @entry_old or it may update @entry_old
in-place.
We must assign @out_obj_old before and not touch @entry_old after
_idxcache_update().
Fixes: cdd8c65799
nmp_lookup_init_route_visible() was originally named this way, to only return routes
that are nmp_object_is_visible(). However, all routes are visible (as long as they are
nmp_object_is_alive()). Hence, this is a historic misnomer.
Also, passing @only_default FALSE is identical to the
nmp_lookup_init_addrroute() lookup.
So, rename the function to indicate it is a lookup for default routes
only. Also, get rid of the unsupported ifindex argument for which there
is no index.
Until now, NetworkManager's platform cache for routes used the quadruple
network/plen,metric,ifindex for equaliy. That is not kernel's
understanding of how routes behave. For example, with `ip route append`
you can add two IPv4 routes that only differ by their gateway. To
the previous form of platform cache, these two routes would wrongly
look identical, as the cache could not contain both routes. This also
easily leads to cache-inconsistencies.
Now that we have NM_PLATFORM_IP_ROUTE_CMP_TYPE_ID, fix the route's
compare operator to match kernel's.
Well, not entirely. Kernel understands more properties for routes then
NetworkManager. Some of these properties may also be part of the ID according
to kernel. To NetworkManager such routes would still look identical as
they only differ in a property that is not understood. This can still
cause cache-inconsistencies. The only fix here is to add support for
all these properties in NetworkManager as well. However, it's less serious,
because with this commit we support several of the more important properties.
See also the related bug rh#1337855 for kernel.
Another difficulty is that `ip route replace` and `ip route change`
changes an existing route. The replaced route has the same
NM_PLATFORM_IP_ROUTE_CMP_TYPE_WEAK_ID, but differ in the actual
NM_PLATFORM_IP_ROUTE_CMP_TYPE_ID:
# ip -d -4 route show dev v
# ip monitor route &
# ip route add 192.168.5.0/24 dev v
192.168.5.0/24 dev v scope link
# ip route change 192.168.5.0/24 dev v scope 10
192.168.5.0/24 dev v scope 10
# ip -d -4 route show dev v
unicast 192.168.5.0/24 proto boot scope 10
Note that we only got one RTM_NEWROUTE message, although from NMPCache's
point of view, a new route (with a particular ID) was added and another
route (with a different ID) was deleted. The cumbersome workaround is,
to keep an ordered list of the routes, and figure out which route was
replaced in response to an RTM_NEWROUTE. In absence of bugs, this should
work fine. However, as we only rely on events, we might wrongly
introduce a cache-inconsistancy as well. See the related bug rh#1337860.
Also drop nm_platform_ip4_route_get() and the like. The ID of routes
is complex, so it makes little sense to look up a route directly.
NMPCache can preserve the order of the objects. Until now, the order
was however arbitrary. Soon we will require to preserve the order of
routes.
During a dump, force appending new objects at the end. That ensures,
correct ordering during the dump.
Note that we track objects in several distrinct indexes. Those partition the
set of all objects. Outside a dump when receiving events about new objects (e.g.
RTM_NEWROUTE), it is very unclear at which place the new object should be sorted.
It is especially unclear, as an object might move from one partition (of
an index) to another.
In general, a deterministic order will only be useful in one particular
instance: the NMP_CACHE_ID_TYPE_ROUTES_BY_DESTINATION index for routes.
In this case, we will ensure a particular order of the routes.
We already had a nmp_object_id_equal() function. Generally, an equal() function
is more useful then a cmp() function.
However, implementing a cmp() function is about the same effort then implementing
an equal() function. Also, an equal function can be trivially implemented based on
a compare function, but not the other way around.
That means, it is little extra effort to have both an equal() function
and a cmp() function. Add nmp_object_id_cmp(). If only to be
consistent with other code, which also provides both.
Routes are complicated.
`ip route add` and `ip route append` behaves differently with respect to
determine whether an existing route is idential or not.
Extend the cmp() and hash() functions to have a compare type, that
covers the different semantics.
and refactor NMFakePlatform to also track links via NMPCache.
For one, now NMFakePlatform also tests NMPCache, increasing the
coverage of what we care about.
Also, all our NMPlatform implementations now use NMPObject and NMPCache.
That means, we can expose those as part of the public API. Which is
great, because callers can keep a reference to the NMPObject object
and make use of generic functions like nmp_object_to_string().
Routes and addresses don't implement cmd_obj_is_visible(),
hence they are always visible, and NMP_CACHE_ID_TYPE_OBJECT_TYPE_VISIBLE_ONLY
is identical to NMP_CACHE_ID_TYPE_OBJECT_TYPE.
Only link objects can be alive but invisible. Still, drop the index
for looking up visible links entirely. Let callers do the filtering,
if they care.
Maintaining an index is expensive.Not so much in term of runtime, but
in term of memory.
Drop some indexes, and require the caller to use a more broad index (and
filter out unwanted elements).
Dropped:
- can no longer lookup visible default-routes by ifindex.
If you care about default-routes, lookup all and search for the
desired ifindex. The overall number of default-routes is expected
to be small.
We drop NMP_CACHE_ID_TYPE_ROUTES_VISIBLE_BY_IFINDEX_WITH_DEFAULT
entirely.
- no longer have a separate index for non-default routes. We
expect that the most routes are non-default routes. So, don't
have an index without default-routes, instead let the caller
just lookup all routes, and reject default-routes themself.
We keep NMP_CACHE_ID_TYPE_ROUTES_VISIBLE_BY_DEFAULT, but it
now no longer tracks non-default routes.
This drops 1 out of 6 route indexes, and modifes another one, so
that we expect that there are almost no entires tracked by it.
Implement the reference counting of NMPObject as part of
NMDedupMultiObj and get rid of NMDedupMultiBox.
With this change, the NMPObject is aware in which NMDedupMultiIndex
instance it is tracked.
- this saves an additional GSlice allocation for the NMDedupMultiBox.
- it is immediately known, whether an NMPObject is tracked by a
certain NMDedupMultiIndex or not. This saves an additional hash
lookup.
- previously, when all idx-types cease to reference an NMDedupMultiObj
instance, it was removed. Now, a tracked objects stays in the
NMDedupMultiIndex until it's last reference is deleted. This possibly
extends the lifetime of the object and we may reuse it better.
- it is no longer possible to add one object to more then one
NMDedupMultiIndex instance. As we anyway want to have only one
instance to deduplicate the objects, this is fine.
- the ref-counting implementation is now part of NMDedupMultiObj.
Previously, NMDedupMultiIndex could also track objects that were
not ref-counted. Hoever, the object anyway *must* implement the
NMDedupMultiObj API, so this flexibility is unneeded and was not
used.
- a downside is, that NMPObject grows by one pointer size, even if
it isn't tracked in the NMDedupMultiIndex. But we really want to
put all objects into the index for sharing and deduplication. So
this downside should be acceptable. Still, code like
nmp_object_stackinit*() needs to handle a larger object.
NMPlatformLnkMacvtap is a typedef of NMPlatformLnkMacvlan, hence, their
plobj implementation is idential. nmp_object_equal() already correctly
compares the object type, so we should hash it too.
Maintaining an index is expensive. We can merge indexes that
are strictly distinct, because one index can just partition the
objects into distinct sets.
Rework platform object cache to use NMDedupMultiIndex.
Already previously, NMPCache used NMMultiIndex and had thus
O(1) for most operations. What is new is:
- Contrary to NMMultiIndex, NMDedupMultiIndex preserves the order of
the cached items. That is crucial to handle routes properly as kernel
will replace the first matching route based on network/plen/metric
properties. See related bug rh#1337855.
Without tracking the order of routes as they are exposed
by kernel, we cannot properly maintain the route cache.
- All NMPObject instances are now treated immutable, refcounted
and get de-duplicated via NMDedupMultiIndex. This allows
to have a global NMDedupMultiIndex that can be shared with
NMIP4Config and NMRouteManager. It also allows to share the
objects themselves.
Immutable objects are so much nicer. We can get rid of the
update pre-hook callback, which was required previously because
we would mutate the object inplace. Now, we can just update
the cache, and compare obj_old and obj_new after the fact.
- NMMultiIndex was treated as an internal of NMPCache. On the other
hand, NMDedupMultiIndex exposes NMDedupMultiHeadEntry, which is
basically an object that allows to iterate over all related
objects. That means, we can now lookup objects in the cache
and give the NMDedupMultiHeadEntry instance to the caller,
which then can iterate the list on it's own -- without need
for copying anything.
Currently, at various places we still create copies of lookup
results. That can be improved later.
The ability to share NMPObject instances should enable us to
significantly improve performance and scale with large number
of routes.
Of course there is a memory overhead of having an index for each list
entry. Each NMPObject may also require an NMDedupMultiEntry,
NMDedupMultiHeadEntry, and NMDedupMultiBox item, which are tracked
in a GHashTable. Optimally, one NMDedupMultiHeadEntry is the head
for multiple objects, and NMDedupMultiBox is able to deduplicate several
NMPObjects, so that there is a net saving.
Also, each object type has several indexes of type NMPCacheIdType.
So, worst case an NMPlatformIP4Route in the platform cache is tracked
by 8 NMPCacheIdType indexes, for each we require a NMDedupMultiEntry,
plus the shared NMDedupMultiHeadEntry. The NMDedupMultiBox instance
is shared between the 8 indexes (and possibly other).
Platform has it's own, simple implementation of object types:
NMPObject. Extract a base type and move it to "shared/nm-utils/nm-obj.h"
so it can be reused.
The base type is trival, but it allows us to implement other objects
which are compatible with NMPObjects. Currently there is no API for generic
NMObjBaseInst type, so compatible in this case only means, that they
can be used in the same context (see example below).
The only thing that you can do with a NMObjBaseInst is check it's
NMObjBaseClass.
Incidentally, NMObjBaseInst is also made compatible to GTypeInstance.
It means, an NMObjBaseInst is not necessarily a valid GTypeInstance (like NMPObject
is not), but it could be implemented as such.
For example, you could do:
if (NMP_CLASS_IS_VALID ((NMPClass *) obj->klass)) {
/* is an NMPObject */
} else if (G_TYPE_CHECK_INSTANCE_TYPE (obj, NM_TYPE_SOMETHING)) {
/* it a NMSometing GType */
} else {
/* something else? */
}
The reason why NMPObject is not implemented as proper GTypeInstance is
because it would require us to register a GType (like
g_type_register_fundamental). However, then the NMPClass struct can
no longer be const and immutable memory. But we could.
NMObjBaseInst may or may not be a GTypeInstance. In a sense, it's
a base type of GTypeInstance and all our objects should be based
on it (optionally, they we may make them valid GTypes too).
Routes with a non-zero host part are not allowed by kernel and
don't really exist. We didn't reject such routes in users configuration,
so various part of NM allow such routes. NM should silently strip
the host part.
Extend the cache's route ID to clear the host part too.
Note that NM's handling of routes is fundamentally flawed, as
for kernels routes don't have an "id" (or rather: all properties
of a route are part of it's ID, not only the family,ifindex,
network/plen and metric tuple (see related bug rh#1337855).
(cherry picked from commit 57b0dce083)
We end up calling nmp_cache_id_init_*() a lot to initialize stack-allocated
cache-ids to lookup the NMMultiIndex. There is no need to memset() it to
zero, because all relevant fields are supposed to be set explicitly.
We call nmp_utils_ethtool_get_driver_info() twice when receiving a
netlink message, but we don't need a clone of the string values.
Instead, expose a data structure that should be stack allocated
by the caller.
The ioctl APIs ethtool/mii require an interface ifname. That is inherrently
racy as interfaces can be renamed. This cannot be fixed, we can only
minimize the time between verifying the ifname and calling ioctl.
We already had problems with that when ethtool would access an interface
by name that didn't exists. See commit ab41c13b06 .
Checking for an existing interface only helps avoiding races when an interface
gets deleted. It does not help against renaming.
Go one step further, and instead of checking whether such an ifname
exists, try to get the ifname based on the ifindex immediately before
we need it.
This brings an additional overhead for each ethtool access.
These logging lines are already disabled by default as _LOGt()
is a NOP unless configured --with-more-logging.
However, the logging is still very verbose also for debug-builds
and currently there are no known issues there. Disable the logging
statements (but leave them in so they can easily be enabled).
(cherry picked from commit 4cb845558e)
We handle cloned routes (that have rtm_flags RTM_F_CLONED) differently.
We used to mark such routes by hacking NMIPConfigSource to have a special
value. No longer do this, because it mixes different concepts.
Note that the rt_cloned filed fits into a hole in the aligment
of NMPlatformIPRoute. Thus there is almost no overhead to this
change.
The "source" field of NMPlatformIPRoute (now "rt_source") maps to the
protocol field of the route. The source of NMPlatformIPAddress (now
"addr_source") has no direct equivalent in the kernel.
As their use is different, they should have different names. Also,
the name "source" is used all over the place. Hence give the fields
a more distinct name.
Consider:
unshare -n
ip link add d0 type dummy
ip link add d1 type dummy
ip link set d0 up
ip link set d1 up
ip addr add 192.168.100.5/24 dev d0
ip addr add 192.168.101.5/24 dev d1
ip route add 192.168.200.0/24 via 192.168.100.1
ip monitor &
ip route change 192.168.200.0/24 via 192.168.101.1
#prints 192.168.200.0/24 via 192.168.101.1 dev d1
ip route show
#192.168.100.0/24 dev d0 proto kernel scope link src 192.168.100.5
#192.168.101.0/24 dev d1 proto kernel scope link src 192.168.101.5
#192.168.200.0/24 via 192.168.101.1 dev d1
Note that `ip route change` replaced the exising route. "Replaced" in this
case means: the previous route on device "d0" got removed and a new route
on "d1" was added. However, kernel only sent one RTM_NEWROUTE event, no
RTM_DELROUTE that notifies about this change.
We need to workaround that by re-synching the routes when we receive a
RTM_NEWROUTE notification.
NMPCacheId is a union with fields for all known NMPCacheIdTypes.
Up to now, we always cloned the entire union, computed the hash
over all (possibly unset) fields and used memcmp() unanimously.
That was ok, because NMPCacheId was 16 bytes in total and cache-id
types that consumed less bytes didn't have a large overhead.
Next, we will add a new cache id type which increases the size of
NMPCacheId to 24 bytes. So, while possibly only a fraction of the
instances is that large, they would all have to pay that price.
Change that to consider and clone only those parts of the id
that are actually used.
