net: Really fix vti6 with oif in dst lookups

6e28b000825d ("net: Fix vti use case with oif in dst lookups for IPv6")
is missing the checks on FLOWI_FLAG_SKIP_NH_OIF. Add them.

Fixes: 42a7b32b73d6 ("xfrm: Add oif to dst lookups")
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_output.c

@@ -877,7 +877,8 @@ static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
 #ifdef CONFIG_IPV6_SUBTREES
 	    ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 #endif
-	    (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
+	   (!(fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) &&
+	      (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex))) {
 		dst_release(dst);
 		dst = NULL;
 	}

net/ipv6/route.c

@@ -1068,6 +1068,9 @@ static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
 	fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
 	saved_fn = fn;
 
+	if (fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF)
+		oif = 0;
+
 redo_rt6_select:
 	rt = rt6_select(fn, oif, strict);
 	if (rt->rt6i_nsiblings)