If an interface is renamed we already have an entry (based on the
ifindex) allocated but previously only set the usable state once
based on the original name.
Fixes#2403.
When querying SAs the keys will end up in this buffer (the allocated
messages that are returned are already wiped). The kernel also returns
XFRM_MSG_NEWSA as response to XFRM_MSG_ALLOCSPI but we can't distinguish
this here as we only see the response.
References #2388.
By using the total retransmit timeout, modifications of timeout settings
automatically reflect on the value of xfrm_acq_expires. If set, the
value of xfrm_acq_expires configured by the user takes precedence over
the calculated value.
When establishing a traffic-triggered CHILD_SA involves the setup of an
IKE_SA more than one exchange is required. As a result the temporary
acquire state may have expired -- even if the acquire expiration
(xfrm_acq_expires) time is set properly (165 by default). The expire
message sent by the kernel is not processed in charon since no trap can
be found by the trap manager.
A possible solution could be to track allocated SPIs. But since this is
a corner case and the tracking introduces quite a bit of overhead, it
seems much more sensible to add a new state if the update of a state
fails with NOT_FOUND.
Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
During initialization of the plugins the thread pool is not yet
initialized so there is no watcher thread that could handle the queued
Netlink message and the main thread will wait indefinitely for a
response.
Fixes#2199.
When constructing the result, all responses from Netlink were concatenated
iteratively, i.e. for each response, the previously acquired result was
copied to newly allocated memory and the current response appended to it.
This results in O(n^2) copy operations. Instead, we now check for the
total final length of the result and copy the individual responses to it
in one pass, i.e. in O(n) copy operations. In particular, this issue caused
very high CPU usage in memcpy() function as the result is copied over and
over. Common way how to hit the issue is when having 1000+ routes and 5+
connecting clients a second. In that case, the memcpy() function can
take 50%+ of one CPU thread on a decent CPU and the whole charon daemon
is stuck just reading routes and concatenating them together (connecting
clients are blocked in that particular case as this is done under mutex).
Closes strongswan/strongswan#65.
References #2055.
For table dumps the kernel accepts RTA_PREFSRC to filter the routes, which is
what we do when doing userspace route calculations. For kernel-based route
lookups, however, the RTA_PREFSRC attribute is ignored and we must specify
RTA_SRC for policy based route lookups.
For gateways with many connections, installing routes is often disabled,
as we can use a static route configuration to achieve proper routing with
a single rule. If this is the case, there is no need to dump all routes and
do userspace route lookups, as there is no need to exclude routes we installed
ourself.
Doing kernel-based route lookups is not only faster with may routes, but also
can use the full power of Linux policy based routing; something we can hardly
rebuild in userspace when calculating routes.
While trap and regular policies now often look the same (mainly because
reqids are kept constant) trap policies still need to have a lower priority
than regular policies to handle unroute/route correctly if e.g. IPComp
is used or the mode changes. But if we use a completely different
priority range that's lower than that of regular policies it is not possible
to install overlapping trap policies. By differentiating trap from
regular policies via the priority's LSB this issue is avoided while
still maintaining the proper ordering of trap and regular policies.
Fixes#1243.
The Optimistic Duplicate Address Detection (DAD) seems to fail in some
cases (`dadfailed` in `ip addr`) rendering the virtual IP address unusable.
Fixes#2183.
This implements rule 6 of RFC 6724 using the default priority table,
so that e.g. global addresses are preferred over ULAs (which also have
global scope) when the destination is a global address.
Fixes#2138.
By default, the kernel incorrectly uses an 8 byte alignment, which is
mandatory for IPv6 but prohibited for IPv4. For many algorithms this
doesn't matter but that's not the case for HMAC_SHA2_256_128.
Since 2.6.39 the kernel can be explicitly configured to use a 4 byte
alignment.
A wrong variable is used (route instead of best), so much that the
returned interface belongs to the last seen route instead of the best
choice route.
get_route() may therefore return mismatching interface and gateway.
Fixes: 66e9165bc6 ("kernel-netlink: Return outbound interface in get_nexthop()")
Signed-off-by: Christophe Gouault <christophe.gouault@6wind.com>
The kernel will apply the mask to the mark on the packet and then
compare it to the configured mark. So to match only unmarked packets we
have to be able to set 0/0xffffffff.
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.
We don't need them for drop policies and they might even mess with other
routes we install. Routes for policies with protocol/ports in the
selector will always be too broad and might conflict with other routes
we install.
Using the source address to determine the interface is not correct for
net-to-net shunts between two interfaces on which the host has IP addresses
for each subnet.
Other threads are free to add/update/delete other policies.
This tries to prevent race conditions caused by releasing the mutex while
sending messages to the kernel. For instance, if break-before-make
reauthentication is used and one thread on the responder is delayed in
deleting the policies that another thread is concurrently adding for the
new SA. This could have resulted in no policies being installed
eventually.
Fixes#1400.
After adding the read callback the state is WATCHER_QUEUED and it is
switched to WATCHER_RUNNING only later by an asynchronous job. This means
that a thread that sent a Netlink message shortly after registration
might see the state as WATCHER_QUEUED. If it then tries to read the
response and the watcher thread is quicker to actually read the message
from the socket, it could block on recv() while still holding the lock.
And the asynchronous job that actually read the message and tries to queue
it will block while trying to acquire the lock, so we'd end up in a deadlock.
This is probably mostly a problem in the unit tests.
Metrics are basically defined to order routes with equal prefix, so ordering
routes by metric first makes not much sense as that could prefer totally
unspecific routes over very specific ones.
For instance, the previous code did break installation of routes for
passthrough policies with two routes like these in the main routing table:
default via 192.168.2.1 dev eth0 proto static
192.168.2.0/24 dev eth0 proto kernel scope link src 192.168.2.10 metric 1
Because the default route has no metric set (0) it was used, instead of the
more specific other one, to determine src and next hop when installing a route
for a passthrough policy for 192.168.2.0/24. Therefore, the installed route
in table 220 did then incorrectly redirect all local traffic to "next hop"
192.168.2.1.
The same issue occurred when determining the source address while
installing trap policies.
Fixes 6b57790270 ("kernel-netlink: Respect kernel routing priorities for IKE routes").
Fixes#1416.
This allows using manual priorities for traps, which have a lower
base priority than the resulting IPsec policies. This could otherwise
be problematic if, for example, swanctl --install/uninstall is used while
an SA is established combined with e.g. IPComp, where the trap policy does
not look the same as the IPsec policy (which is now otherwise often the case
as the reqids stay the same).
It also orders policies by selector size if manual priorities are configured
and narrowing occurs.
The kernel policy now considers src and dst port masks as well as
restictions to a given network interface. The base priority is
100'000 for passthrough shunts, 200'000 for IPsec policies,
300'000 for IPsec policy traps and 400'000 for fallback drop shunts.
The values 1..30'000 can be used for manually set priorities.
Tobias Brunner