It is a prep work for the later bug-fix patch which will stop /128 route
from disappearing after pmtu update.
The later bug-fix patch will allow a /128 route and its RTF_CACHE clone
both exist at the same fib6_node. To do this, we need to prepare the
existing fib6 tree search to expect RTF_CACHE for /128 route.
Note that the fn->leaf is sorted by rt6i_metric. Hence,
RTF_CACHE (if there is any) is always at the front. This property
leads to the following:
1. When doing ip6_route_del(), it should honor the RTF_CACHE flag which
the caller is used to ask for deleting clone or non-clone.
The rtm_to_fib6_config() should also check the RTM_F_CLONED and
then set RTF_CACHE accordingly so that:
- 'ip -6 r del...' will make ip6_route_del() to delete a route
and all its clones. Note that its clones is flushed by fib6_del()
- 'ip -6 r flush table cache' will make ip6_route_del() to
only delete clone(s).
2. Exclude RTF_CACHE from addrconf_get_prefix_route() which
should not configure on a cloned route.
3. No change is need for rt6_device_match() since it currently could
return a RTF_CACHE clone route, so the later bug-fix patch will not
affect it.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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