Refactor LXC network setup to allow future enhancements

The current lxcSetupInterfaces() method directly performs setup
of the bridge devices. Since it will shortly need to also create
macvlan devices, move the bridge related code into a separate
method

* src/lxc/lxc_driver.c: Split lxcSetupInterfaces() to create a
  new lxcSetupInterfaceBridge()

src/lxc/lxc_driver.c

@@ -1175,6 +1175,61 @@ static void lxcVmCleanup(lxc_driver_t *driver,
     }
 }
 
+
+static int lxcSetupInterfaceBridged(virConnectPtr conn,
+                                    virDomainNetDefPtr net,
+                                    const char *brname,
+                                    unsigned int *nveths,
+                                    char ***veths)
+{
+    int ret = -1;
+    char *parentVeth;
+    char *containerVeth = NULL;
+
+    VIR_DEBUG("calling vethCreate()");
+    parentVeth = net->ifname;
+    if (virNetDevVethCreate(&parentVeth, &containerVeth) < 0)
+        goto cleanup;
+    VIR_DEBUG("parentVeth: %s, containerVeth: %s", parentVeth, containerVeth);
+
+    if (net->ifname == NULL)
+        net->ifname = parentVeth;
+
+    if (VIR_REALLOC_N(*veths, (*nveths)+1) < 0) {
+        virReportOOMError();
+        VIR_FREE(containerVeth);
+        goto cleanup;
+    }
+    (*veths)[(*nveths)] = containerVeth;
+    (*nveths)++;
+
+    if (virNetDevSetMAC(containerVeth, net->mac) < 0)
+        goto cleanup;
+
+    if (virNetDevBridgeAddPort(brname, parentVeth) < 0)
+        goto cleanup;
+
+    if (virNetDevSetOnline(parentVeth, true) < 0)
+        goto cleanup;
+
+    if (virNetDevBandwidthSet(net->ifname,
+                              virDomainNetGetActualBandwidth(net)) < 0) {
+        lxcError(VIR_ERR_INTERNAL_ERROR,
+                 _("cannot set bandwidth limits on %s"),
+                 net->ifname);
+        goto cleanup;
+    }
+
+    if (net->filter &&
+        virDomainConfNWFilterInstantiate(conn, net) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+cleanup:
+    return ret;
+}
+
 /**
  * lxcSetupInterfaces:
  * @conn: pointer to connection
@@ -1193,39 +1248,56 @@ static int lxcSetupInterfaces(virConnectPtr conn,
                               unsigned int *nveths,
                               char ***veths)
 {
-    int rc = -1, i;
-    char *bridge = NULL;
+    int ret = -1;
+    size_t i;
 
     for (i = 0 ; i < def->nnets ; i++) {
-        char *parentVeth;
-        char *containerVeth = NULL;
-
         /* If appropriate, grab a physical device from the configured
          * network's pool of devices, or resolve bridge device name
          * to the one defined in the network definition.
          */
         if (networkAllocateActualDevice(def->nets[i]) < 0)
-            goto error_exit;
+            goto cleanup;
 
         switch (virDomainNetGetActualType(def->nets[i])) {
-        case VIR_DOMAIN_NET_TYPE_NETWORK:
-        {
+        case VIR_DOMAIN_NET_TYPE_NETWORK: {
             virNetworkPtr network;
+            char *brname = NULL;
 
-            network = virNetworkLookupByName(conn,
-                                             def->nets[i]->data.network.name);
-            if (!network) {
-                goto error_exit;
-            }
-
-            bridge = virNetworkGetBridgeName(network);
+            if (!(network = virNetworkLookupByName(conn,
+                                                   def->nets[i]->data.network.name)))
+                goto cleanup;
 
+            brname = virNetworkGetBridgeName(network);
             virNetworkFree(network);
+            if (!brname)
+                goto cleanup;
+
+            if (lxcSetupInterfaceBridged(conn,
+                                         def->nets[i],
+                                         brname,
+                                         nveths,
+                                         veths) < 0) {
+                VIR_FREE(brname);
+                goto cleanup;
+            }
+            VIR_FREE(brname);
             break;
         }
-        case VIR_DOMAIN_NET_TYPE_BRIDGE:
-            bridge = virDomainNetGetActualBridgeName(def->nets[i]);
-            break;
+        case VIR_DOMAIN_NET_TYPE_BRIDGE: {
+            const char *brname = virDomainNetGetActualBridgeName(def->nets[i]);
+            if (!brname) {
+                lxcError(VIR_ERR_INTERNAL_ERROR, "%s",
+                         _("No bridge name specified"));
+                goto cleanup;
+            }
+            if (lxcSetupInterfaceBridged(conn,
+                                         def->nets[i],
+                                         brname,
+                                         nveths,
+                                         veths) < 0)
+                goto cleanup;
+        }   break;
 
         case VIR_DOMAIN_NET_TYPE_USER:
         case VIR_DOMAIN_NET_TYPE_ETHERNET:
@@ -1235,64 +1307,23 @@ static int lxcSetupInterfaces(virConnectPtr conn,
         case VIR_DOMAIN_NET_TYPE_INTERNAL:
         case VIR_DOMAIN_NET_TYPE_DIRECT:
         case VIR_DOMAIN_NET_TYPE_LAST:
-            break;
-        }
-
-        VIR_DEBUG("bridge: %s", bridge);
-        if (NULL == bridge) {
             lxcError(VIR_ERR_INTERNAL_ERROR,
-                     "%s", _("Failed to get bridge for interface"));
-            goto error_exit;
-        }
-
-        VIR_DEBUG("calling vethCreate()");
-        parentVeth = def->nets[i]->ifname;
-        if (virNetDevVethCreate(&parentVeth, &containerVeth) < 0)
-            goto error_exit;
-        VIR_DEBUG("parentVeth: %s, containerVeth: %s", parentVeth, containerVeth);
-
-        if (NULL == def->nets[i]->ifname) {
-            def->nets[i]->ifname = parentVeth;
-        }
-
-        if (VIR_REALLOC_N(*veths, (*nveths)+1) < 0) {
-            virReportOOMError();
-            VIR_FREE(containerVeth);
-            goto error_exit;
-        }
-        (*veths)[(*nveths)] = containerVeth;
-        (*nveths)++;
-
-        if (virNetDevSetMAC(containerVeth, def->nets[i]->mac) < 0)
-            goto error_exit;
-
-        if (virNetDevBridgeAddPort(bridge, parentVeth) < 0)
-            goto error_exit;
-
-        if (virNetDevSetOnline(parentVeth, true) < 0)
-            goto error_exit;
-
-        if (virNetDevBandwidthSet(def->nets[i]->ifname,
-                                  virDomainNetGetActualBandwidth(def->nets[i])) < 0) {
-            lxcError(VIR_ERR_INTERNAL_ERROR,
-                     _("cannot set bandwidth limits on %s"),
-                     def->nets[i]->ifname);
-            goto error_exit;
+                     _("Unsupported network type %s"),
+                     virDomainNetTypeToString(
+                         virDomainNetGetActualType(def->nets[i])
+                         ));
+            goto cleanup;
         }
-
-        if (def->nets[i]->filter &&
-            virDomainConfNWFilterInstantiate(conn, def->nets[i]) < 0)
-            goto error_exit;
     }
 
-    rc = 0;
+    ret= 0;
 
-error_exit:
-    if (rc != 0) {
+cleanup:
+    if (ret != 0) {
         for (i = 0 ; i < def->nnets ; i++)
             networkReleaseActualDevice(def->nets[i]);
     }
-    return rc;
+    return ret;
 }