net: ipv4: Make "ip route get" match iif lo rules again.
Commit 3765d35e ("net: ipv4: Convert inet_rtm_getroute to rcu versions of route lookup") broke "ip route get" in the presence of rules that specify iif lo. Host-originated traffic always has iif lo, because ip_route_output_key_hash and ip6_route_output_flags set the flow iif to LOOPBACK_IFINDEX. Thus, putting "iif lo" in an ip rule is a convenient way to select only originated traffic and not forwarded traffic. inet_rtm_getroute used to match these rules correctly because even though it sets the flow iif to 0, it called ip_route_output_key which overwrites iif with LOOPBACK_IFINDEX. But now that it calls ip_route_output_key_hash_rcu, the ifindex will remain 0 and not match the iif lo in the rule. As a result, "ip route get" will return ENETUNREACH. Fixes: 3765d35e ("net: ipv4: Convert inet_rtm_getroute to rcu versions of route lookup") Tested: https://android.googlesource.com/kernel/tests/+/master/net/test/multinetwork_test.py passes again Signed-off-by: Lorenzo Colitti <lorenzo@google.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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