Since f52cf07532 addresses on ignored, down or loopback interfaces were
not considered as valid addresses anymore when searching for an address
contained in the local traffic selector. This meant that route
installation failed, for instance, if charon.install_virtual_ip_on was
set to 'lo', or, on gateways, if internal interfaces were ignored with
the charon.interfaces_* options.
This new flag gives the kernel-interface a hint how it should priorize the
use of newly installed SAs during rekeying.
Consider the following rekey procedure in IKEv2:
Initiator --- Responder
I1 -------CREATE-------> R1
I2 <------CREATE--------
-------DELETE-------> R2
I3 <------DELETE--------
SAs are always handled as pairs, the following happens at the SA level:
* Initiator starts the exchange at I1
* Responder installs new SA pair at R1
* Initiator installs new SA pair at I2
* Responder removes old SA pair at R2
* Initiator removes old SA pair at I3
This makes sure SAs get installed/removed overlapping during rekeying. However,
to avoid any packet loss, it is crucial that the new outbound SA gets
activated at the correct position:
* as exchange initiator, in I2
* as exchange responder, in R2
This should guarantee that we don't use the new outbound SA before the peer
could install its corresponding inbound SA.
The new parameter allows the kernel backend to install the new SA with
appropriate priorities, i.e. it should:
* as exchange inititator, have the new outbound SA installed with higher
priority than the old SA
* as exchange responder, have the new outbound SA installed with lower
priority than the old SA
While we could split up the SA installation at the responder, this approach
has another advantage: it allows the kernel backend to switch SAs based on
other criteria, for example when receiving traffic on the new inbound SA.
If routes installed along with policies covering the peer address affect local
IKE/ESP packets, they won't get routed correctly. To work around this issue,
the kernel interface can install "exclude" routes for the IKE peer. Not all
networking backends require this workaround, hence we export a flag for it
if it is required.
Conflicts:
configure.in
man/ipsec.conf.5.in
src/libcharon/daemon.c
src/libcharon/plugins/eap_ttls/eap_ttls_peer.c
src/libcharon/plugins/eap_radius/eap_radius_accounting.c
src/libcharon/plugins/eap_radius/eap_radius_forward.c
src/libcharon/plugins/farp/farp_listener.c
src/libcharon/sa/ike_sa.c
src/libcharon/sa/keymat.c
src/libcharon/sa/task_manager.c
src/libcharon/sa/trap_manager.c
src/libstrongswan/plugins/x509/x509_cert.c
src/libstrongswan/utils.h
Applied lost changes of moved files keymat.c and task_manager.c.
Updated listener_t.message hook signature in new plugins.
During the update of a CHILD_SA (e.g. caused by MOBIKE) the old policy
is first uninstalled and then the new one is installed. In the short
time in between, where no policy is available in the kernel, unencrypted
packets could have been transmitted.
This allows to unroute a connection while the same connection is
currently established. In this case both CHILD_SAs share the same
reqid but the installed policies have different priorities.
Tobias Brunner