This is needed to fix usage stats sent via RADIUS Accounting if clients
use MOBIKE or e.g. the kernel notifies us about a changed NAT mapping.
The upper layers won't expect the stats to get reset if only the IPs have
changed (and some kernel interface might actually allow such updates
without reset).
It also fixes traffic based lifetimes in such situations.
Fixes#799.
The current "inbound" flag is used for two purposes: To define the actual
direction of the SA, but also to determine the operation used for SA
installation. If an SPI has been allocated, an update operation is required
instead of an add.
While the inbound flag normally defines the kind of operation required, this
is not necessarily true in all cases. On the HA passive node, we install inbound
SAs without prior SPI allocation.
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 a system uses routing metrics, we should honor them when doing (manual)
routing lookups for IKE. When enumerating routes, the kernel reports priorities
with the RTA_PRIORITY attribute, not RTA_METRICS. We prefer routes with a
lower priority value, and fall back to longest prefix match priorities if
the priority value is equal.
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.
To reassign reqids where appropriate, we explicitly allocate or confirm them
centrally on the kernel-interface.
Currently the state is stored in the kernel-interface wrapper for all
backends, but we may add appropriate methods to each backend to implement
a custom reqid allocation logic, if required.
While we can handle the first selector only in BEET mode in kernel-netlink,
passing the full list gives the backend more flexibility how to handle this
information.
The reqid is not strictly required, as we set the reqid with the update
call when installing the negotiated SA.
If we don't need a reqid at this stage, we can later allocate the reqid in
the kernel backend once the SA parameters have been fully negotaited. This
allows us to assign the same reqid for the same selectors to avoid conflicts
on backends this is necessary.
On OS X 10.10, when installing a virtual IP on a tun device, there is a chance
that a RTM_IFANNOUNCE is sent before the IP is ready on that link when calling
getifaddrs(). As we don't get an RTM_NEWADDR event either, that race lets us
miss the virtual IP install event, failing the add_ip() call.
The FreeBSD and Mac OS X kernels interpret sadb_sa_replay as the size of the
replay window in bytes. Linux on the other hand does the same for PF_KEY it
does for XFRM so sadb_sa_replay denotes the number of packets/bits in the
window. Similarly, the window size on Linux is limited to 32 by the four
byte default bitmap used for IPsec SAs (may only be changed with
XFRMA_REPLAY_ESN_VAL), which is not the case on the other platforms.
As some backends over unreliable transport do not cache response messages,
retransmissions due the loss of responses perform the operation again. Add an
option to ignore some errors arising from such duplicate operations.
Note: This approach can't distinguish between real EXIST/NOTFOUND errors
and packet failures, and therefore is a source of race conditions and can't
detect any of these errors actually happening. Therefore that behavior is
disabled by default, and can be enabled with the ignore_retransmit_errors
strongswan.conf option.
To properly distinguish between real and retransmission errors, a Netlink
backend should implement retransmission detection using sequence numbers.
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.
As under vanilla Linux the kernel can't handle parallel dump queries and returns
EBUSY, it makes not much sense to use them. Disable parallel queries by default
to basically restore original behavior, improving performance.
Besides that it can improve throughput, it avoids a deadlock situation. If
all threads are busy, watcher will invoke the FD notification for NEWADDR
events itself. If the lock is held, it gets locked up. As watcher is not
dispatching anymore, it can't signal Netlink socket send() completion, and
the send() operation does not return and keeps the lock.
If the kernel can't execute a Netlink query because a different query is already
active, it returns EBUSY. As this can happen now as we support parallel queries,
retry on this error condition.
Instead of locking the socket exclusively to wait for replies, use watcher
to wait for and read in responses asynchronously. This allows multiple parallel
Netlink queries, which can significantly improve performance if the kernel
Netlink layer has longer latencies and supports parallel queries.
For vanilla Linux, parallel queries don't make much sense, as it usually returns
EBUSY for the relevant dump requests. This requires a retry, and in the end
makes queries more expensive under high load.
Instead of checking the Netlink message sequence number to detect multi-part
messages, this code now relies on the NLM_F_MULTI flag to detect them. This
has previously been avoided (by 1d51abb7). It is unclear if the flag did not
work correctly on very old Linux kernels, or if the flag was not used
appropriately by strongSwan. The flag seems to work just fine back to 2.6.18,
which is a kernel still in use by RedHat/CentOS 5.
If no offline leases are available for the current client and assigning online
leases is disabled, and if all IPs of the pool have already been assigned to
clients we look for offline leases that previously were assigned to other
clients.
In case the current client has online leases the previous code would
replace the existing mapping entry and besides resulting in a memory leak
the online leases would be lost forever (even if the client later releases
the addresses). If this happens repeatedly the number of available addresses
would decrease even though the total number of online and offline leases seen
in `ipsec leases` would indicate that there are free addresses available.
Fixes#764.
Previously one more than the first and last address was ignored.
And if the base address is not the network ID of the subnet we
should not skip it. But we should adjust the size as it does not
represent the actual number of IP addresses assignable.
Since 4b670a20 we require an explicit strongswan.conf to re-load configurations.
However, the define was missing in the build, breaking SIGHUP based config
reloading.
Fixes#651.
Martin Willi