This is needed to handle DELETEs properly, which was previously done via
CHILD_REKEYING, which we don't use anymore since 5c6a62ceb6 as it prevents
reauthentication.
As we now use the same reqid for multiple CHILD_SAs with the same selectors,
having marks based on the reqid makes not that much sense anymore. Instead we
use unique marks that use a custom identifier. This identifier is reused during
rekeying, keeping the marks constant for any rule relying on it (for example
installed by updown).
This also simplifies handling of reqid allocation, as we do not have to query
the marks that is not yet assigned for an unknown reqid.
If a peer immediately sends DELETE messages when completing Quick Mode rekeying,
the third Quick Mode message and the DELETE are sent simultaneously. This
implies that DELETE messages may arrive before the completing third Quick Mode
message.
Handle this case by ignoring the DELETE INFORMATIONAL in Quick Mode and let
the delete task handle it.
If PFS is configured for a CHILD_SA first try to create a list of
proposals with using DH group negotiated during phase 1. If the
resulting list is empty (i.e. the DH group(s) configured for PFS differ
from the one(s) configured for the IKE_SA), fall back to the first
configured DH group from the CHILD_SA.
This modificiation is due to the fact that it is likely that the peer
supports the same DH group for PFS it did already for the IKE_SA.
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.
While this was problematic in earlier releases, it seems that it works just
fine the way we handle compression now. So there is no need to disable it over
NATed connections or when using forceencaps.
If two peers rekey Quick Modes at the same time, the original Quick Mode is
in REKEYING state and hence the requid is not reused. This is required though,
as two identical policies won't work if they have different requids.
Cisco 5505 firewalls don't return the port if we send a specific one, letting
the is_contained_in() checks fail. Using get_subset() selection builds the
Quick Mode correctly with the common subset of selectors.
Based on an initial patch from Paul Stewart.
According to RFC 2409, section 5.5, if PFS is used all proposals MUST
include the selected DH group, so we remove proposals without the
proposed group and remove other DH groups from the remaining proposals.
Windows 7 sends its internal address as TSi. While we don't support the
NAT-T drafts as used by Windows XP it is interesting to note that the
client there omits the TSi payload which then would automatically get set
to the public IP address of the client.
Fixes#220.
Tobias Brunner