vxlan: fix test which detect duplicate vxlan iface

[ Upstream commit 07b9b37c227cb8d88d478b4a9c5634fee514ede1 ]

When a vxlan interface is created, the driver checks that there is not
another vxlan interface with the same properties. To do this, it checks
the existing vxlan udp socket. Since commit 1c51a9159dde, the creation of
the vxlan socket is done only when the interface is set up, thus it breaks
that test.

Example:
$ ip l a vxlan10 type vxlan id 10 group 239.0.0.10 dev eth0 dstport 0
$ ip l a vxlan11 type vxlan id 10 group 239.0.0.10 dev eth0 dstport 0
$ ip -br l | grep vxlan
vxlan10          DOWN           f2:55:1c:6a:fb:00 <BROADCAST,MULTICAST>
vxlan11          DOWN           7a:cb:b9:38:59:0d <BROADCAST,MULTICAST>

Instead of checking sockets, let's loop over the vxlan iface list.

Fixes: 1c51a9159dde ("vxlan: fix race caused by dropping rtnl_unlock")
Reported-by: Thomas Faivre <thomas.faivre@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 2826c550876266a1ca68cbf46092b9688d6063fc..59282dd2d9e0217961ebad1170363021bc3c8e8d 100644 (file)
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2433,7 +2433,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
                         struct nlattr *tb[], struct nlattr *data[])
 {
        struct vxlan_net *vn = net_generic(net, vxlan_net_id);
-       struct vxlan_dev *vxlan = netdev_priv(dev);
+       struct vxlan_dev *vxlan = netdev_priv(dev), *tmp;
        struct vxlan_rdst *dst = &vxlan->default_dst;
        __u32 vni;
        int err;
@@ -2554,9 +2554,13 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
            nla_get_u8(data[IFLA_VXLAN_UDP_ZERO_CSUM6_RX]))
                vxlan->flags |= VXLAN_F_UDP_ZERO_CSUM6_RX;
 
-       if (vxlan_find_vni(net, vni, use_ipv6 ? AF_INET6 : AF_INET,
-                          vxlan->dst_port)) {
-               pr_info("duplicate VNI %u\n", vni);
+       list_for_each_entry(tmp, &vn->vxlan_list, next) {
+               if (tmp->default_dst.remote_vni == vni &&
+                   (tmp->default_dst.remote_ip.sa.sa_family == AF_INET6 ||
+                    tmp->saddr.sa.sa_family == AF_INET6) == use_ipv6 &&
+                   tmp->dst_port == vxlan->dst_port &&
+                   (tmp->flags & VXLAN_F_RCV_FLAGS) ==
+                   (vxlan->flags & VXLAN_F_RCV_FLAGS))
                return -EEXIST;
        }
 

diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 903461aa5644ce9d1e366818fa6cbda1ba0cc1b1..2f3572f03f58886cabeaf8486acdc96347169cbf 100644 (file)
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -43,6 +43,11 @@ struct vxlan_sock {
 #define VXLAN_F_UDP_ZERO_CSUM6_TX      0x80
 #define VXLAN_F_UDP_ZERO_CSUM6_RX      0x100
 
+/* Flags that are used in the receive path. These flags must match in
+ * order for a socket to be shareable
+ */
+#define VXLAN_F_RCV_FLAGS              VXLAN_F_UDP_ZERO_CSUM6_RX
+                                        
 struct vxlan_sock *vxlan_sock_add(struct net *net, __be16 port,
                                  vxlan_rcv_t *rcv, void *data,
                                  bool no_share, u32 flags);