vxlan: Only bind to sockets with compatible flags enabled

A VXLAN net_device looking for an appropriate socket may only consider
a socket which has a matching set of flags/extensions enabled. If
incompatible flags are enabled, return a conflict to have the caller
create a distinct socket with distinct port.

The OVS VXLAN port is kept unaware of extensions at this point.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 6dbf8e041922..6b6b45622a0a 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -263,15 +263,19 @@ static inline struct vxlan_rdst *first_remote_rtnl(struct vxlan_fdb *fdb)
         return list_first_entry(&fdb->remotes, struct vxlan_rdst, list);
 }
 
-/* Find VXLAN socket based on network namespace, address family and UDP port */
-static struct vxlan_sock *vxlan_find_sock(struct net *net,
-                                          sa_family_t family, __be16 port)
+/* Find VXLAN socket based on network namespace, address family and UDP port
+ * and enabled unshareable flags.
+ */
+static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
+                                          __be16 port, u32 flags)
 {
         struct vxlan_sock *vs;
+        u32 match_flags = flags & VXLAN_F_UNSHAREABLE;
 
         hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
                 if (inet_sk(vs->sock->sk)->inet_sport == port &&
-                    inet_sk(vs->sock->sk)->sk.sk_family == family)
+                    inet_sk(vs->sock->sk)->sk.sk_family == family &&
+                    (vs->flags & VXLAN_F_UNSHAREABLE) == match_flags)
                         return vs;
         }
         return NULL;
@@ -291,11 +295,12 @@ static struct vxlan_dev *vxlan_vs_find_vni(struct vxlan_sock *vs, u32 id)
 
 /* Look up VNI in a per net namespace table */
 static struct vxlan_dev *vxlan_find_vni(struct net *net, u32 id,
-                                        sa_family_t family, __be16 port)
+                                        sa_family_t family, __be16 port,
+                                        u32 flags)
 {
         struct vxlan_sock *vs;
 
-        vs = vxlan_find_sock(net, family, port);
+        vs = vxlan_find_sock(net, family, port, flags);
         if (!vs)
                 return NULL;
 
@@ -1957,7 +1962,8 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 
                         ip_rt_put(rt);
                         dst_vxlan = vxlan_find_vni(vxlan->net, vni,
-                                                   dst->sa.sa_family, dst_port);
+                                                   dst->sa.sa_family, dst_port,
+                                                   vxlan->flags);
                         if (!dst_vxlan)
                                 goto tx_error;
                         vxlan_encap_bypass(skb, vxlan, dst_vxlan);
@@ -2016,7 +2022,8 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 
                         dst_release(ndst);
                         dst_vxlan = vxlan_find_vni(vxlan->net, vni,
-                                                   dst->sa.sa_family, dst_port);
+                                                   dst->sa.sa_family, dst_port,
+                                                   vxlan->flags);
                         if (!dst_vxlan)
                                 goto tx_error;
                         vxlan_encap_bypass(skb, vxlan, dst_vxlan);
@@ -2186,7 +2193,7 @@ static int vxlan_init(struct net_device *dev)
 
         spin_lock(&vn->sock_lock);
         vs = vxlan_find_sock(vxlan->net, ipv6 ? AF_INET6 : AF_INET,
-                             vxlan->dst_port);
+                             vxlan->dst_port, vxlan->flags);
         if (vs && atomic_add_unless(&vs->refcnt, 1, 0)) {
                 /* If we have a socket with same port already, reuse it */
                 vxlan_vs_add_dev(vs, vxlan);
@@ -2593,7 +2600,7 @@ struct vxlan_sock *vxlan_sock_add(struct net *net, __be16 port,
                 return vs;
 
         spin_lock(&vn->sock_lock);
-        vs = vxlan_find_sock(net, ipv6 ? AF_INET6 : AF_INET, port);
+        vs = vxlan_find_sock(net, ipv6 ? AF_INET6 : AF_INET, port, flags);
         if (vs && ((vs->rcv != rcv) ||
                    !atomic_add_unless(&vs->refcnt, 1, 0)))
                         vs = ERR_PTR(-EBUSY);
@@ -2761,7 +2768,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
                 vxlan->flags |= VXLAN_F_GBP;
 
         if (vxlan_find_vni(net, vni, use_ipv6 ? AF_INET6 : AF_INET,
-                           vxlan->dst_port)) {
+                           vxlan->dst_port, vxlan->flags)) {
                 pr_info("duplicate VNI %u\n", vni);
                 return -EEXIST;
         }