ofproto-dpif: Avoid creating OpenFlow ports for duplicate tunnels.

Until now, when two tunnels had an identical configuration, both of them
were assigned OpenFlow ports, but only one of those OpenFlow ports was
functional.  With this commit, only one of the two (or more) identically
configured tunnels will be assigned an OpenFlow port number.

Reported-by: Keith Holleman <hollemanietf@gmail.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Co-authored-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>

AUTHORS

@@ -277,6 +277,7 @@ Joan Cirer              joan@ev0.net
 John Darrington         john@darrington.wattle.id.au
 John Galgay             john@galgay.net
 John Hurley             john.hurley@netronome.com
+Keith Holleman          hollemanietf@gmail.com
 K 華                    k940545@hotmail.com
 Kevin Mancuso           kevin.mancuso@rackspace.com
 Kiran Shanbhog          kiran@vmware.com

ofproto/ofproto-dpif.c

@@ -1671,8 +1671,14 @@ port_construct(struct ofport *port_)
 
     if (netdev_get_tunnel_config(netdev)) {
         atomic_count_inc(&ofproto->backer->tnl_count);
-        tnl_port_add(port, port->up.netdev, port->odp_port,
-                     ovs_native_tunneling_is_on(ofproto), namebuf);
+        error = tnl_port_add(port, port->up.netdev, port->odp_port,
+                             ovs_native_tunneling_is_on(ofproto), namebuf);
+        if (error) {
+            atomic_count_dec(&ofproto->backer->tnl_count);
+            dpif_port_destroy(&dpif_port);
+            return error;
+        }
+
         port->is_tunnel = true;
         if (ofproto->ipfix) {
            dpif_ipfix_add_tunnel_port(ofproto->ipfix, port_, port->odp_port);

ofproto/tunnel.c

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013, 2014 Nicira, Inc.
+/* Copyright (c) 2013, 2014, 2015 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -203,14 +203,20 @@ tnl_port_add__(const struct ofport_dpif *ofport, const struct netdev *netdev,
 
 /* Adds 'ofport' to the module with datapath port number 'odp_port'. 'ofport's
  * must be added before they can be used by the module. 'ofport' must be a
- * tunnel. */
-void
+ * tunnel.
+ *
+ * Returns 0 if successful, otherwise a positive errno value. */
+int
 tnl_port_add(const struct ofport_dpif *ofport, const struct netdev *netdev,
              odp_port_t odp_port, bool native_tnl, const char name[]) OVS_EXCLUDED(rwlock)
 {
+    bool ok;
+
     fat_rwlock_wrlock(&rwlock);
-    tnl_port_add__(ofport, netdev, odp_port, true, native_tnl, name);
+    ok = tnl_port_add__(ofport, netdev, odp_port, true, native_tnl, name);
     fat_rwlock_unlock(&rwlock);
+
+    return ok ? 0 : EEXIST;
 }
 
 /* Checks if the tunnel represented by 'ofport' reconfiguration due to changes

ofproto/tunnel.h

@@ -1,4 +1,4 @@
-/* Copyright (c) 2013 Nicira, Inc.
+/* Copyright (c) 2013, 2015 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -33,8 +33,8 @@ void ofproto_tunnel_init(void);
 bool tnl_port_reconfigure(const struct ofport_dpif *, const struct netdev *,
                           odp_port_t, bool native_tnl, const char name[]);
 
-void tnl_port_add(const struct ofport_dpif *, const struct netdev *,
-                  odp_port_t odp_port, bool native_tnl, const char name[]);
+int tnl_port_add(const struct ofport_dpif *, const struct netdev *,
+                 odp_port_t odp_port, bool native_tnl, const char name[]);
 void tnl_port_del(const struct ofport_dpif *);
 
 const struct ofport_dpif *tnl_port_receive(const struct flow *);