This avoids a network meltdown in extreme cases.
Thanks to Teco Boot.

(cherry picked from commit a4fd38d4)

The purpose of the this new filter is to override *locally*:
- RTA_SRC ('from' option in ip-route)
- RTA_PREFSRC ('src' in ip-route)

TODO: documentation

To be pushed upstream.

To be pushed upstream.
Co-authored-by: Julien Muchembled <jm@nexedi.com>

TODO: documentation

To be pushed upstream.
Co-authored-by: Julien Muchembled <jm@nexedi.com>

To be pushed upstream.

There is no equivalent config-file option, since I'm worried about config
files being copied between nodes.

This patch fix the non-disambiguation behaviour: we were looking to
disambiguation entries to remove or replace, which is a complete non-sense,
since there should not being disambiguation entries.

Sigh.

This is simpler and avoids issues with changing router-ids.

This increases the chances for a stable router-id in case the set of
interfaces changes.

This fixes compilation under musl.

This fixes compilation under musl.

Based on the kernel version, can be overridden explicitly.

Prefixes are counted in bits, not in bytes.  It is safe to compare all
16 bytes, since prefixes are always normalised -- they have zeroes beyond
the prefix length, see mask_prefix.  Alternatively, we could use
prefix_cmp.

Was used in the first version of the disambiguation.c algorithm.

This reverts commit 9edf0a14.