Add option 'netlink rx buffer' to specify netlink socket receive buffer
size. Uses SO_RCVBUFFORCE, so it can override rmem_max limit.
Thanks to Trisha Biswas and Michal for the original patches.
Add strict checking for netlink KRT dumps to avoid PMTU cache records
from FNHE table dump along with KRT.
Linux Kernel added FNHE table dump to the netlink API in patch:
8d3b68cd37.1561131177.git.sbrivio@redhat.com/
Therefore, since Linux 5.3 these route cache entries are dumped together
with regular routes during periodic KRT scans, which in some cases may be
huge amount of useless data. This can be avoided by using strict checking
for netlink dumps:
https://lore.kernel.org/netdev/20181008031644.15989-1-dsahern@kernel.org/
The patch mitigates the risk of receiving unknown and potentially large
number of FNHE records that would block BIRD I/O in each sync. There is a
known issue caused by the GRE tunnels on Linux that seems to be creating
one FNHE record for each destination IP address that is routed through
the tunnel, even when the PMTU equals to GRE interface MTU.
Thanks to Tomas Hlavacek for the original patch.
Kernel uses cloned routes to keep route cache entries, but reports them
together with regular routes. They were skipped implicitly as they
do not have rtm_protocol filled. Add explicit check for cloned flag
and skip such routes explicitly.
Also, improve debug logs of skipped routes.
Add option to socket interface for nonlocal binding, i.e. binding to an
IP address that is not present on interfaces. This behaviour is enabled
when SKF_FREEBIND socket flag is set. For Linux systems, it is
implemented by IP_FREEBIND socket flag.
Minor changes done by commiter.
Currently, BIRD ignores dead routes to consider them absent. But it also
ignores its own routes and thus it can not correctly manage such routes
in some cases. This patch makes an exception for routes with proto bird
when ignoring dead routes, so they can be properly updated or removed.
Thanks to Alexander Zubkov for the original patch.
The BSD kernel does not support the onlink flag and BIRD does not use
direct routes for next hop validation, instead depends on interface
address ranges. We would like to handle PtMP cases with only host
addresses configured, like:
ifconfig wg0 192.168.0.10/32
route add 192.168.0.4 -iface wg0
route add 192.168.0.8 -iface wg0
To accept BIRD routes with onlink next-hop, like:
route 192.168.42.0/24 via 192.168.0.4%wg0 onlink
BIRD would dismiss the route when receiving from the kernel, as the
next-hop 192.168.0.4 is not part of any interface subnet and onlink
flag is not kept by the BSD kernel.
The commit fixes this by assuming that for routes received from the
kernel, any next-hop is onlink on ifaces with only host addresses.
Thanks to Stefan Haller for the original patch.
We can also quite simply allocate bigger blocks. Anyway, we need these
blocks to be aligned to their size which needs one mmap() two times
bigger and then two munmap()s returning the unaligned parts.
The user can specify -B <N> on startup when <N> is the exponent of 2,
setting the block size to 2^N. On most systems, N is 12, anyway if you
know that your configuration is going to eat gigabytes of RAM, you are
almost forced to raise your block size as you may easily get into memory
fragmentation issues or you have to raise your maximum mapping count,
e.g. "sysctl vm.max_map_count=(number)".
Add a wrapper function in sysdep to get random bytes, and required checks
in configure.ac to select how to do it. The configure script tries, in
order, getrandom(), getentropy() and reading from /dev/urandom.
The BSD code did not propagate the OS-level IFF_MULTICAST flag to the
Bird-internal IF_MULTICAST flag, which causes problems with Wireguard
interfaces on FreeBSD. The Linux sysdep code does propagate the flag
already, so just copy over the same check and flag update.
For logging purposes a stack allocated net_addr struct was passed by
value as vararg (instead of the expected pointer). This resulted in
a segfault when the specific error condition got logged.
From now, there are no auxiliary pointers stored in the free slab nodes.
This led to strange debugging problems if use-after-free happened in
slab-allocated structures, especially if the structure's first member is
a next pointer.
This also reduces the memory needed by 1 pointer per allocated object.
OTOH, we now rely on pages being aligned to their size's multiple, which
is quite common anyway.
In general, events are code handling some some condition, which is
scheduled when such condition happened and executed independently from
I/O loop. Work-events are a subgroup of events that are scheduled
repeatedly until some (often significant) work is done (e.g. feeding
routes to protocol). All scheduled events are executed during each
I/O loop iteration.
Separate work-events from regular events to a separate queue and
rate limit their execution to a fixed number per I/O loop iteration.
That should prevent excess latency when many work-events are
scheduled at one time (e.g. simultaneous reload of many BGP sessions).
This is an implementation of draft-walton-bgp-hostname-capability-02.
It is implemented since quite some time for FRR and in datacenter, this
gives a nice output to avoid using IP addresses.
It is disabled by default. The hostname is retrieved from uname(2) and
can be overriden with "hostname" option. The domain name is never set
nor displayed.
Minor changes by committer.
With net.ipv4.conf.XXX.ignore_routes_with_linkdown sysctl, a user can
ensure the kernel does not use a route whose target interface is down.
Such route is marked with a 'dead' / RTNH_F_DEAD flag.
Ignore these routes or multipath nexthops during scan.
Thanks to Vincent Bernat for the original patch.
So one can define kernel protocol template without channels.
For other protocols, it is either irrelevant or already done.
Thanks to Clemens Schrimpe for the bugreport.
For ECMP routes, RTA_FLOW attribute must be set per-nexthop, not
per-route. Our corresponding krt_realm attribute is per-route.
Thanks to Mikhail Petrov for the bugreport.
