The nodeUpdater interface was meant to reduce the methods needed to
implement a fake CiliumNode client in multi-pool unit tests. For the
sake of simplicity, let's remove the interface and use the typed client
directly, just like the majority of the other Cilium packages. Moreover,
now that the multi-pool manager is being modernized, the unit tests will
be reworked lated to rely on the hive provided fake clientset, removing
the need for a custom fake CiliumNode client altogether.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

In preparation for reusing the multi-pool manager for the upcoming
Cilium Network driver IPAM, let's remove the direct dependency of the
manager from the daemon configuration. Instead, just pass each
configuration option as a function parameter. This allows to easily
instantiate an additional manager instance feeding it with a separate
set of options.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

There is no need to create the CiliumNode resource in the multi-pool
manager initializer, since for cluster pool and multi pool modes it is
already done during the daemon initial configuration (see
configureDaemon). Therefore, remove initial CiliumNode update and the
dependency from node discovery.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

In multi-pool IPAM mode, after a restart the manager is in charge of
propagating an initial update of the local CiliumNode. This should be
done once the information about the requested and allocated pools in the
k8s resource have been received, so that the node discovery does not
propagate spurious update the external kvstore.  Since this operation is
needed only for pod IPAM, in order to reuse the multi-pool code in other
contexts (e.g: multi-pool IPAM for DRA resources) let's move the local
node initial update outside of the manager code. Since we are at it,
rename some internal fields to improve readability.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

The multi-pool manager is in charge of propagating the local node
allocation CIDRs updates to the local node store that, in turn,
propagates this information to all the other cluster's nodes for
inter-node routing.

Since this logic is specific to the context of pod IPAM, let's move it
to a separate job that is started then the daemon bootstraps the IPAM
subsystem. Thanks to the resource internal implementation, opening an
additional events stream for the local node does not have any additional
overhead (i.e: the same informer is used to feed the additional
subscriber).

Also, fix unit tests accordingly.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

In order to improve the reusability of the multi-pool package, let's
clearly separate the parts specific for pod IPAM, like the Allocator and
the local node allocations CIDRs synchronization, and the ones that
implement the core logic, like the manager.

This allows to reuse the multi-pool IPAM core logic in the context of
the upcoming Cilium Network driver.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

Since multi-pool package is about to be used in contexts other than the
pod IPAM (like DRA resources IPAM), let's remove all the explicit
reference to pods in the multi-pool code and instead mention only
generic "CIDRs".

This commit does not intend to change anything in the multi-pool
behavior.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

In the context of pod IPAM, at startup, the multi-pool manager should
wait for all preallocated CiliumPodIPPools to be loaded into stateDB.
This is needed to check the existing annotations on the pools later
during addresses assignment.

In order to keep all pod IPAM specific logic into the allocator and away
from the core manager, let's move this logic into the pod IPAM
allocator.  The timeout for this wait is limited to 1 minute since the
pools should be inserted immediately at startup by the k8s reflector.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

Move the skip masquerade feature to the pod IPAM Allocator. The
multi-pool manager exposes a function parameter that, given a pool name,
returns a boolean to understand if masquerading for pool addresses
should be skipped or not. Doing this allows to keep the logic tied to
CiliumPodIPPool, specific for pod IPAM, outside of the core manager.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>

With the upcoming multi-pool resources IPAM for the Cilium Network
Driver, the multi-pool manager should be able to read pools information
from different CiliumNode fields (e.g: Spec.IPAM.Pools for pods and
Spec.IPAM.ResourcePools for DRA resources). Similarly, the manager
should update the allocations status using different fields in the
CiliumNode. Therefore, add a function parameter to the manager to
extract the proper pools reference from the CiliumNode object. This
allows the customization of the manager instance based on the needs of
the specific context.

Signed-off-by: Fabio Falzoi <fabio.falzoi@isovalent.com>