Merge branch 'fib_validate_loopback'

Cong Wang says:

====================
ipv4: fix flowi4_iif for input routing

This patchset fixes ->flowi4_iif for input routing and rp filter,
based on suggestion from Julian. See per patch for details.

v1 -> v2:
* merge the first two patches into one
* fix fib_check_nh() too
* add this cover letter
====================

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>