This way we don't rely on the order of equally matching configs as
heavily anymore (which is actually tricky in vici) and this also doesn't
require repeating weak algorithms in all configs that might potentially be
selected if there are some clients that require them.
There is currently no ordering, so an explicitly configured exactly matching
proposal isn't a better match than e.g. the default proposal that also
contains the proposed algorithms.
We don't have MOBIKE and the fallback to reauthentication does also not
make much sense as that doesn't affect the CHILD_SAs for IKEv1. So
instead of complicating the code we just ignore roam events for IKEv1
for now.
Closesstrongswan/strongswan#100.
If the responder is behind a NAT that remaps the response from the
statically forwarded port 500 to a new external port (as Azure seems to be
doing) we should still switch to port 4500 if we used port 500 so far as
it would not have been possible to send any messages to it if it wasn't
really port 500 (we only add a non-ESP marker if neither port is 500).
Reqids for the same traffic selectors are now stable so we don't have to
pass reqids of previously installed CHILD_SAs. Likewise, we don't need
to know the reqid of the newly installed trap policy as we now uninstall
by name.
IKE_SAs newly created via HA_IKE_ADD message don't have any IKE or peer
config assigned yet (this happens later with an HA_IKE_UPDATE message).
And because the state is initially set to IKE_CONNECTING the roam() method
does not immediately return, as it later would for passive HA SAs. This
might cause the check for explicitly configured local addresses to crash
the daemon with a segmentation fault.
Fixes#2500.
In case we send retransmits for an IKE_SA_INIT where we propose a DH
group the responder will reject we might later receive delayed responses
that either contain INVALID_KE_PAYLOAD notifies with the group we already
use or, if we retransmitted an IKE_SA_INIT with the requested group but
then had to restart again, a KE payload with a group different from the
one we proposed. So far we didn't change the initiator SPI when
restarting the connection, i.e. these delayed responses were processed
and might have caused fatal errors due to a failed DH negotiation or
because of the internal retry counter in the ike-init task. Changing
the initiator SPI avoids that as we won't process the delayed responses
anymore that caused this confusion.
Some devices always use the oldest IKE_SA to send DPDs and will delete
all IKE_SAs when there is no response. If uniqueness is not enforced
rekeyed IKE_SAs might not get deleted until they expire so we should
respond to DPDs.
References #2090.
When multihomed, a setup might prefer to dynamically stay on the cheapest
available path by using MOBIKE migrations. If the cheapest path goes away and
comes back, we currently stay on the more expensive path to reduce noise and
prevent potential migration issues. This is usually just fine for links not
generating real cost.
If we have more expensive links in the setup, it can be desirable to always
migrate to the cheapest link available. By setting charon.prefer_best_path,
charon tries to migrate to the path using the highest priority link, allowing
an external application to update routes to indirectly control MOBIKE behavior.
This option has no effect if MOBIKE is unavailable.
Disabling MOBIKE and statically configuring a local address should be
enough indication that the user doesn't want to roam to a different
address. There might not be any routes that indicate we can use the
current address but it might still work (e.g. if the address is on an
interface that is not referenced in any routes and the address itself
is neither). This way we avoid switching to another address for routes
that might be available on the system.
We currently don't make much use of COND_STALE anyway when MOBIKE is not
enabled, e.g. to avoid sending DPDs if the connection is seemingly down.
With MOBIKE enabled we don't exactly check that state but we do don't
send DPDs if there is no route/source address available.
If we silently delete the IKE_SA the other peer might still use it even
if only to send DPDs. If we don't answer to DPDs that might result in the
deletion of the new IKE_SA too.
This is the minimum size an IPv6 implementation must support. This makes
it the default for IPv4 too, which presumably is also generally routable
(otherwise, setting this to 0 falls back to the minimum of 576 for IPv4).
Some tasks might get removed immediately once the IKE_SA_INIT response has
been handled even if there were notifies that require a restart of the
IKE_SA (e.g. COOKIE or INVALID_KE_PAYLOAD). Such a task is ike_vendor,
which caused vendor IDs not to get sent in a retry. This change ensures
all required tasks are queued after the reset, which some callers did
already anyway.
Such a task is not initiated unless a certain time has passed. This
allows delaying certain tasks but avoids problems if we'd do this
via a scheduled job (e.g. if the IKE_SA is rekeyed in the meantime).
If the IKE_SA is rekeyed the delay of such tasks is reset when the
tasks are adopted i.e. they get executed immediately on the new IKE_SA.
This hasn't been implemented for IKEv1 yet.
This makes handling such IKE_SAs more specifically compared to keeping them
in state IKE_CONNECTING or IKE_ESTABLISHED (which we did when we lost a
collision - even triggering the ike_updown event), or using IKE_REKEYING for
them, which would also be ambiguous.
For instance, we can now reject anything but DELETES for such SAs.
This is the case for the IKE_SA_INIT and the initial IKEv1 messages, which
are pre-generated in tasks as at least parts of it are used to generate
the AUTH payload. The IKE_SA_INIT message will never be fragmented, but
the IKEv1 messages might be, so we can't just call generate_message().
Fixes#1478.
If the SA got redirected this would otherwise cause a reauthentication with
the original gateway. Reestablishing the SA to the original gateway, if e.g.
the new gateway is not reachable makes sense though.
We handle this similar to how we do reestablishing IKE_SAs with all CHILD_SAs,
which also includes the one actively queued during IKE_AUTH.
To delete the old SA we use the recently added ike_reauth_complete task.
If there is no path to the other peer there is no point in trying to
send a NAT keepalive.
If the condition changes back and forth within the keepalive interval there
is a chance that multiple jobs get queued.
When reestablishing the IKE_SA we should still use the original port
when right resolves to %any as some implementations might not like
initial IKE messages on port 4500 (especially for IKEv1).
In some situations it might be valid for a host that configures
right=%any to reestablish or reauthenticate an IKE_SA. Using %any would
immediately abort the initiation causing the new SA to fail (which
might already have the existing CHILD_SAs assigned).
Fixes#1027.
If static local addresses are configured we should use their address family
as a hint when resolving the remote address.
We don't do this if %any is configured as this might break existing
configurations (%any4 and %any6 are however used as hint).
Tobias Brunner