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).
If the number of flows over a gateway exceeds the flow cache size of the Linux
kernel, policy lookup gets very expensive. Policies covering more than a single
address don't get hash-indexed by default, which results in wasting most of
the cycles in xfrm_policy_lookup_bytype() and its xfrm_policy_match() use.
Starting with several hundred policies the overhead gets inacceptable.
Starting with Linux 3.18, Linux can hash the first n-bit of a policy subnet
to perform indexed lookup. With correctly chosen netbits, this can completely
eliminate the performance impact of policy lookups, freeing the resources
for ESP crypto.
WARNING: Due to a bug in kernels 3.19 through 4.7, the kernel crashes with a
NULL pointer dereference if a socket policy is installed while hash thresholds
are changed. And because the hashtable rebuild triggered by the threshold
change that causes this is scheduled it might also happen if the socket
policies are seemingly installed after setting the thresholds.
The fix for this bug - 6916fb3b10b3 ("xfrm: Ignore socket policies when
rebuilding hash tables") - is included since 4.8 (and might get backported).
As a workaround `charon.plugins.kernel-netlink.port_bypass` may be enabled
to replace the socket policies that allow IKE traffic with port specific
bypass policies.
When charon rekeys a CHILD_SA after a soft limit expired, it is only
deleted after the hard limit is reached. In case of packet/byte limits
this may not be the case for a long time since the packets/bytes are
usually sent using the new SA. This may result in a very large number of
stale CHILD_SAs and kernel states. With enough connections configured this
will ultimately exhaust the memory of the system.
This patch adds a strongswan.conf setting that, if enabled, causes the old
CHILD_SA to be deleted by the initiator after a successful rekeying.
Enabling this setting might create problems with implementations that
continue to use rekeyed SAs (e.g. if the DELETE notify is lost).
With IKEv1 we have to reuse IKE_SAs as otherwise the responder might
detect the new SA as reauthentication and will "adopt" the CHILD_SAs of
the original IKE_SA, while the initiator will not do so. This could
cause CHILD_SA rekeying to fail later.
Fixes#1236.
This can be useful when writing custom plugins as typos or missing
linker flags that result in unresolved symbols in the shared object
could otherwise cause late crashes. In particular, if such a symbol
is used in a code path that is rarely executed. During development
and testing using RTLD_NOW instead of RTLD_LAZY will prevent the
plugin from getting loaded and makes the error visible immediately.
Some clients won't do Mode Config or XAuth during reauthentication.
Because Start messages previously were triggered by TRANSACTION exchanges
none were sent for new SAs of such clients, while Stop messages were still
sent for the old SAs when they were destroyed. This resulted in an
incorrect state on the RADIUS server.
Since 31be582399 the assign_vips() event is also triggered during
reauthentication if the client does not do a Mode Config exchange.
So instead of waiting for a TRANSACTION exchange we trigger the Start
message when a virtual IP is assigned to a client.
With this the charon.plugins.eap-radius.accounting_requires_vip option
would not have any effect for IKEv1 anymore. However, it previously also
only worked if the client did an XAuth exchange, which is probably
rarely used without virtual IPs, so this might not be much of a
regression.
Fixes#937.
The kernel uses NLMSG_GOODSIZE as default buffer size, which defaults to
the PAGE_SIZE if it is lower than 8192 or to that value otherwise.
In some cases (e.g. for dump messages) the kernel might use up to 16k
for messages, which might require increasing this value.
The specific traffic selectors from the acquire events, which are derived
from the triggering packet, are usually prepended to those from the
config. Some implementations might not be able to handle these properly.
References #860.
If many requests are sent to the kernel the events generated by these
requests may fill the receive buffer before the daemon is able to read
these messages.
Fixes#783.
If this is disabled the schemes configured in `rightauth` are only
checked against signature schemes used in the certificate chain and
signature schemes used during IKEv2 are ignored.
Disabling this could be helpful if existing connections with peers that
don't support RFC 7427 use signature schemes in `rightauth` to verify
certificate chains.
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.
The socket based IKE bypass policies are usually superior, but not supported
on all networking stacks. The port based variant uses global policies for the
UDP ports we have IKE sockets for.
Any interval returned by the RADIUS server in the Access-Accept message
overrides the configured interval. But it might be useful if RADIUS is
only used for accounting.