[PATCH 0/8] More genericization of struct rtable

This patch set does more work to minimize or completely eliminate
various fields of struct rtable, with the goal of making the
structure as generic and non-specific as possible.

First we reduce rt->rt_tos such that it is only used as a key
for routing cache lookups, and rename it rt->rt_key_tos to
reflect this fact.

Next some output route lookup interface tweaks leading to the
removal of several rt->rt_{dst,src} accesses, replacing those
with flowi4->{daddr,saddr}

More to come.