Add basic VRF (virtual routing and forwarding) support. Protocols can be
associated with VRFs, such protocols will be restricted to interfaces
assigned to the VRF (as reported by Linux kernel) and will use sockets
bound to the VRF. E.g., different multihop BGP instances can use diffent
kernel routing tables to handle BGP TCP connections.
The VRF support is preliminary, currently there are several limitations:
- Recent Linux kernels (4.11) do not handle correctly sockets bound
to interaces that are part of VRF, so most protocols other than multihop
BGP do not work. This will be fixed by future kernel versions.
- Neighbor cache ignores VRFs. Breaks config with the same prefix on
local interfaces in different VRFs. Not much problem as single hop
protocols do not work anyways.
- Olock code ignores VRFs. Breaks config with multiple BGP peers with the
same IP address in different VRFs.
- Incoming BGP connections are not dispatched according to VRFs.
Breaks config with multiple BGP peers with the same IP address in
different VRFs. Perhaps we would need some kernel API to read VRF of
incoming connection? Or probably use multiple listening sockets in
int-new branch.
- We should handle master VRF interface up/down events and perhaps
disable associated protocols when VRF goes down. Or at least disable
associated interfaces.
- Also we should check if the master iface is really VRF iface and
not some other kind of master iface.
- BFD session request dispatch should be aware of VRFs.
- Perhaps kernel protocol should read default kernel table ID from VRF
iface so it is not necessary to configure it.
- Perhaps we should have per-VRF default table.
This makes BIRD send a wildcard retraction on all interfaces before
shutting down and right after starting up. This helps ensure that
neighbours will discard the announced routes as soon as possible,
rather than only after the normal timeout procedures.
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
An update with wildcard AE and infinite metric should be treated as a
global retraction of all prefixes announced by that neighbour, per
section 4.4.9 of the RFC. In addition, router ID and seqno in retraction
updates should be ignored. This reworks the handling of retractions and
adjusts the parser to handle all this correctly.
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
This patch implements the IPv6 subset of the Babel routing protocol.
Based on the patch from Toke Hoiland-Jorgensen, with some heavy
modifications and bugfixes.
Thanks to Toke Hoiland-Jorgensen for the original patch.
