net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup

ipv6_stub uses the ip6_dst_lookup function to allow other modules to
perform IPv6 lookups. However, this function skips the XFRM layer
entirely.

All users of ipv6_stub->ip6_dst_lookup use ip_route_output_flow (via the
ip_route_output_key and ip_route_output helpers) for their IPv4 lookups,
which calls xfrm_lookup_route(). This patch fixes this inconsistent
behavior by switching the stub to ip6_dst_lookup_flow, which also calls
xfrm_lookup_route().

This requires some changes in all the callers, as these two functions
take different arguments and have different return types.

Fixes: 5f81bd2e5d80 ("ipv6: export a stub for IPv6 symbols used by vxlan")
Reported-by: Xiumei Mu <[e-mail]>
Signed-off-by: Sabrina Dubroca <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/infiniband/core/addr.c

···
 				(const struct sockaddr_in6 *)dst_sock;
 	struct flowi6 fl6;
 	struct dst_entry *dst;
-	int ret;
 
 	memset(&fl6, 0, sizeof fl6);
 	fl6.daddr = dst_in->sin6_addr;
 	fl6.saddr = src_in->sin6_addr;
 	fl6.flowi6_oif = addr->bound_dev_if;
 
-	ret = ipv6_stub->ipv6_dst_lookup(addr->net, NULL, &dst, &fl6);
-	if (ret < 0)
-		return ret;
+	dst = ipv6_stub->ipv6_dst_lookup_flow(addr->net, NULL, &fl6, NULL);
+	if (IS_ERR(dst))
+		return PTR_ERR(dst);
 
 	if (ipv6_addr_any(&src_in->sin6_addr))
 		src_in->sin6_addr = fl6.saddr;

drivers/infiniband/sw/rxe/rxe_net.c

···
 	memcpy(&fl6.daddr, daddr, sizeof(*daddr));
 	fl6.flowi6_proto = IPPROTO_UDP;
 
-	if (unlikely(ipv6_stub->ipv6_dst_lookup(sock_net(recv_sockets.sk6->sk),
-						recv_sockets.sk6->sk, &ndst, &fl6))) {
+	ndst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(recv_sockets.sk6->sk),
+					       recv_sockets.sk6->sk, &fl6,
+					       NULL);
+	if (unlikely(IS_ERR(ndst))) {
 		pr_err_ratelimited("no route to %pI6\n", daddr);
-		goto put;
+		return NULL;
 	}
 
 	if (unlikely(ndst->error)) {

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c

···
 
 	int ret;
 
-	ret = ipv6_stub->ipv6_dst_lookup(dev_net(mirred_dev), NULL, &dst,
-					 fl6);
-	if (ret < 0)
-		return ret;
+	dst = ipv6_stub->ipv6_dst_lookup_flow(dev_net(mirred_dev), NULL, fl6,
+					      NULL);
+	if (IS_ERR(dst))
+		return PTR_ERR(dst);
 
 	if (!(*out_ttl))
 		*out_ttl = ip6_dst_hoplimit(dst);

drivers/net/geneve.c

···
 		if (dst)
 			return dst;
 	}
-	if (ipv6_stub->ipv6_dst_lookup(geneve->net, gs6->sock->sk, &dst, fl6)) {
+	dst = ipv6_stub->ipv6_dst_lookup_flow(geneve->net, gs6->sock->sk, fl6,
+					      NULL);
+	if (IS_ERR(dst)) {
 		netdev_dbg(dev, "no route to %pI6\n", &fl6->daddr);
 		return ERR_PTR(-ENETUNREACH);
 	}

drivers/net/vxlan.c

···
 	bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
 	struct dst_entry *ndst;
 	struct flowi6 fl6;
-	int err;
 
 	if (!sock6)
 		return ERR_PTR(-EIO);
···
 	fl6.fl6_dport = dport;
 	fl6.fl6_sport = sport;
 
-	err = ipv6_stub->ipv6_dst_lookup(vxlan->net,
-					 sock6->sock->sk,
-					 &ndst, &fl6);
-	if (unlikely(err < 0)) {
+	ndst = ipv6_stub->ipv6_dst_lookup_flow(vxlan->net, sock6->sock->sk,
+					       &fl6, NULL);
+	if (unlikely(IS_ERR(ndst))) {
 		netdev_dbg(dev, "no route to %pI6\n", daddr);
 		return ERR_PTR(-ENETUNREACH);
 	}

include/net/ipv6_stubs.h

···
 				 const struct in6_addr *addr);
 	int (*ipv6_sock_mc_drop)(struct sock *sk, int ifindex,
 				 const struct in6_addr *addr);
-	int (*ipv6_dst_lookup)(struct net *net, struct sock *sk,
-			       struct dst_entry **dst, struct flowi6 *fl6);
+	struct dst_entry *(*ipv6_dst_lookup_flow)(struct net *net,
+						  const struct sock *sk,
+						  struct flowi6 *fl6,
+						  const struct in6_addr *final_dst);
 	int (*ipv6_route_input)(struct sk_buff *skb);
 
 	struct fib6_table *(*fib6_get_table)(struct net *net, u32 id);

net/core/lwt_bpf.c

···
 		fl6.daddr = iph6->daddr;
 		fl6.saddr = iph6->saddr;
 
-		err = ipv6_stub->ipv6_dst_lookup(net, skb->sk, &dst, &fl6);
-		if (unlikely(err))
-			goto err;
+		dst = ipv6_stub->ipv6_dst_lookup_flow(net, skb->sk, &fl6, NULL);
 		if (IS_ERR(dst)) {
 			err = PTR_ERR(dst);
 			goto err;

net/ipv6/addrconf_core.c

···
 }
 EXPORT_SYMBOL(inet6addr_validator_notifier_call_chain);
 
-static int eafnosupport_ipv6_dst_lookup(struct net *net, struct sock *u1,
-					struct dst_entry **u2,
-					struct flowi6 *u3)
+static struct dst_entry *eafnosupport_ipv6_dst_lookup_flow(struct net *net,
+							   const struct sock *sk,
+							   struct flowi6 *fl6,
+							   const struct in6_addr *final_dst)
 {
-	return -EAFNOSUPPORT;
+	return ERR_PTR(-EAFNOSUPPORT);
 }
 
 static int eafnosupport_ipv6_route_input(struct sk_buff *skb)
···
 }
 
 const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
-	.ipv6_dst_lookup   = eafnosupport_ipv6_dst_lookup,
+	.ipv6_dst_lookup_flow = eafnosupport_ipv6_dst_lookup_flow,
 	.ipv6_route_input  = eafnosupport_ipv6_route_input,
 	.fib6_get_table    = eafnosupport_fib6_get_table,
 	.fib6_table_lookup = eafnosupport_fib6_table_lookup,

net/ipv6/af_inet6.c

···
 static const struct ipv6_stub ipv6_stub_impl = {
 	.ipv6_sock_mc_join = ipv6_sock_mc_join,
 	.ipv6_sock_mc_drop = ipv6_sock_mc_drop,
-	.ipv6_dst_lookup   = ip6_dst_lookup,
+	.ipv6_dst_lookup_flow = ip6_dst_lookup_flow,
 	.ipv6_route_input  = ipv6_route_input,
 	.fib6_get_table	   = fib6_get_table,
 	.fib6_table_lookup = fib6_table_lookup,

net/mpls/af_mpls.c

···
 	struct net_device *dev;
 	struct dst_entry *dst;
 	struct flowi6 fl6;
-	int err;
 
 	if (!ipv6_stub)
 		return ERR_PTR(-EAFNOSUPPORT);
 
 	memset(&fl6, 0, sizeof(fl6));
 	memcpy(&fl6.daddr, addr, sizeof(struct in6_addr));
-	err = ipv6_stub->ipv6_dst_lookup(net, NULL, &dst, &fl6);
-	if (err)
-		return ERR_PTR(err);
+	dst = ipv6_stub->ipv6_dst_lookup_flow(net, NULL, &fl6, NULL);
+	if (IS_ERR(dst))
+		return ERR_CAST(dst);
 
 	dev = dst->dev;
 	dev_hold(dev);

net/tipc/udp_media.c

···
 				.saddr = src->ipv6,
 				.flowi6_proto = IPPROTO_UDP
 			};
-			err = ipv6_stub->ipv6_dst_lookup(net, ub->ubsock->sk,
-							 &ndst, &fl6);
-			if (err)
+			ndst = ipv6_stub->ipv6_dst_lookup_flow(net,
+							       ub->ubsock->sk,
+							       &fl6, NULL);
+			if (IS_ERR(ndst)) {
+				err = PTR_ERR(ndst);
 				goto tx_error;
+			}
 			dst_cache_set_ip6(cache, ndst, &fl6.saddr);
 		}
 		ttl = ip6_dst_hoplimit(ndst);