net: ipv6: Add RT6_LOOKUP_F_IFACE flag if oif is set

Wolfgang reported that IPv6 stack is ignoring oif in output route lookups: With ipv6, ip -6 route get always returns the specific route. $ ip -6 r 2001:db8:e2::1 dev enp2s0 proto kernel metric 256 2001:db8:e2::/64 dev enp2s0 metric 1024 2001:db8:e3::1 dev enp3s0 proto kernel metric 256 2001:db8:e3::/64 dev enp3s0 metric 1024 fe80::/64 dev enp3s0 proto kernel metric 256 default via 2001:db8:e3::255 dev enp3s0 metric 1024 $ ip -6 r get 2001:db8:e2::100 2001:db8:e2::100 from :: dev enp2s0 src 2001:db8:e3::1 metric 0 cache $ ip -6 r get 2001:db8:e2::100 oif enp3s0 2001:db8:e2::100 from :: dev enp2s0 src 2001:db8:e3::1 metric 0 cache The stack does consider the oif but a mismatch in rt6_device_match is not considered fatal because RT6_LOOKUP_F_IFACE is not set in the flags. Cc: Wolfgang Nothdurft <[email protected]> Signed-off-by: David Ahern <[email protected]> Signed-off-by: David S. Miller <[email protected]>
mdmillerii · Sep 29, 2015 · 741a11d · 741a11d
1 parent 75c261b
commit 741a11d
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
@@ -1193,7 +1193,8 @@ struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
 
 	fl6->flowi6_iif = LOOPBACK_IFINDEX;
 
-	if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr))
+	if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr) ||
+	    fl6->flowi6_oif)
 		flags |= RT6_LOOKUP_F_IFACE;
 
 	if (!ipv6_addr_any(&fl6->saddr))