If uniqueness checks are disabled and multiple IKE_SAs with the same
identities are created, an offline lease could have gotten reassigned
during a make-before-break reauthentication if such an SA was closed
earlier. Checking for an online lease for the same client (IP/port)
first ensures that the correct IP is reassigned during the
reauthentication.
References strongswan/strongswan#2472
Instead of just adding the offset internally, this way the reported
base address is always the first assignable address (e.g. for
192.168.0.0/24 vs. 192.168.0.1/24).
Closesstrongswan/strongswan#2264
If a base address is configured, we don't expect the pool to be empty,
so reject the creation (e.g. with the broadcast address as base).
References strongswan/strongswan#2205
Also assign online leases to a peer connecting from the same endpoint
when it requests any virtual IP. This is mainly a workaround for
Windows clients that remember the virtual IPv6 address and re-request it
the next time the connection is initiated (even if it is not a
reauthentication) but don't do the same for virtual IPv4 addresses.
This can result in duplicate policies with different reqids because
these are allocated for unique sets of traffic selectors.
Fixes#3541.
With make-before-break IKEv2 re-authentication, virtual IP addresses must be
assigned overlapping to the same peer. With the remote IKE address, the backend
can detect re-authentication attempts by comparing the remote host address and
port. This allows proper reassignment of the virtual IP if it is re-requested.
This change removes the mem-pool.reassign_online option, as it is obsolete now.
IPs get automatically reassigned if a peer re-requests the same address, and
additionally connects from the same address and port.
Tobias Brunner