net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup

commit 6c8991f41546c3c472503dff1ea9daaddf9331c2 upstream.

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 <xmu@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 4.19:
 - Drop change in lwt_bpf.c
 - Delete now-unused "ret" in mlx5e_route_lookup_ipv6()
 - Initialise "out_dev" in mlx5e_create_encap_header_ipv6() to avoid
   introducing a spurious "may be used uninitialised" warning
 - Adjust filenames, context, indentation]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

3 files changed, 11 insertions, 12 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index c8928ce69185..3050853774ee 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -2217,12 +2217,11 @@ static int mlx5e_route_lookup_ipv6(struct mlx5e_priv *priv,
 #if IS_ENABLED(CONFIG_INET) && IS_ENABLED(CONFIG_IPV6)
 	struct mlx5e_rep_priv *uplink_rpriv;
 	struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
-	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);
@@ -2428,7 +2427,7 @@ static int mlx5e_create_encap_header_ipv6(struct mlx5e_priv *priv,
 	int max_encap_size = MLX5_CAP_ESW(priv->mdev, max_encap_header_size);
 	int ipv6_encap_size = ETH_HLEN + sizeof(struct ipv6hdr) + VXLAN_HLEN;
 	struct ip_tunnel_key *tun_key = &e->tun_info.key;
-	struct net_device *out_dev;
+	struct net_device *out_dev = NULL;
 	struct neighbour *n = NULL;
 	struct flowi6 fl6 = {};
 	u8 nud_state, tos, ttl;
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index ff83408733d4..36444de701cd 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -801,7 +801,9 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
 		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);
 	}
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 64751b089482..7ee0bad18466 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1963,7 +1963,6 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
 	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);
@@ -1986,10 +1985,9 @@ static struct dst_entry *vxlan6_get_route(struct vxlan_dev *vxlan,
 	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);
 	}