Protocol can have specified VRF, in such case it is restricted to a set
of ifaces associated with the VRF, otherwise it can use all interfaces.

The patch allows to specify VRF as 'default', in which case it is
restricted to a set of iface not associated with any VRF.

The formatting was broken when too short router-id was used.

Includes patch from Maximilian Eschenbacher

Mismatched types to printf(). The old code coincidentally worked on amd64
due to its calling conventions.

Thanks to Maximilian Eschenbacher for the bugreport.

Allow multiple BFD instances in separate VRFs, dispatch BFD requests
according to VRFs.

Thanks to Alexander Zubkov for notice and patches.

Use route replace netlink op instead of delete+add netlink ops for kernel
IPv4 route replace. This avoids some packetloss during route replace.
Still use the old behavior for IPv6, as some kernel bugs are hidden in
IPv6 ECMP handling.

Per RFC 3101, N-bit signalling NSSA support should be used only in Hello
packets, not in DBDES packets. BIRD since 2.0.4 verifies N-bit in
neighbor structure, which is learned from DBDES packets, therefore
NSSA-LSAs are not propagated to proper implementations of RFC 3101.

This patch fixes that. Both removing the check and removing N-bit from
DBDES packet. This will fix compatibility issues with proper
implementations, but causes compatibility issues with BIRD 2.0.4.

This led in corner cases to undefined buffer content
and garbage output.

Most LSA origination is blocked in ospf_update_topology(), this fix
blocks LSA origination from ospf_rt_spf().

When priority is reconfigured locally, we need to trigger DR election.

(recommiting, was reset by the previous commit)

We need to flush learned external LSAs a bit later than other LSAs (after
first feed after end of the graceful restart) to avoid flap of external
routes.

Thanks to Vincent Bernat for reporting this.

When priority is reconfigured locally, we need to trigger DR election.

Nest requires that nexthops are sorted, the kernel protocol have to
ensure that for alien routes.