net: ipv6: add net argument to ip6_dst_lookup_flow

commit c4e85f73afb6384123e5ef1bba3315b2e3ad031e upstream.

This will be used in the conversion of ipv6_stub to ip6_dst_lookup_flow,
as some modules currently pass a net argument without a socket to
ip6_dst_lookup. This is equivalent to commit 343d60aada5a ("ipv6: change
ipv6_stub_impl.ipv6_dst_lookup to take net argument").

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 11407dd..d93a98d 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1075,19 +1075,19 @@
  *	It returns a valid dst pointer on success, or a pointer encoded
  *	error code.
  */
-struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
+struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
 				      const struct in6_addr *final_dst)
 {
 	struct dst_entry *dst = NULL;
 	int err;
 
-	err = ip6_dst_lookup_tail(sock_net(sk), sk, &dst, fl6);
+	err = ip6_dst_lookup_tail(net, sk, &dst, fl6);
 	if (err)
 		return ERR_PTR(err);
 	if (final_dst)
 		fl6->daddr = *final_dst;
 
-	return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0);
+	return xfrm_lookup_route(net, dst, flowi6_to_flowi(fl6), sk, 0);
 }
 EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow);
 
@@ -1112,7 +1112,7 @@
 
 	dst = ip6_sk_dst_check(sk, dst, fl6);
 	if (!dst)
-		dst = ip6_dst_lookup_flow(sk, fl6, final_dst);
+		dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_dst);
 
 	return dst;
 }