network: clear ifindeces

We need to clear any ifindeces we recorded so liblxc won't have cached stale
data which would cause it to fail on reboot we're we don't re-read the on-disk
config file.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

src/lxc/network.c

@@ -2334,36 +2334,49 @@ bool lxc_delete_network_unpriv(struct lxc_handler *handler)
 				TRACE("Renamed interface with index %d to its "
 				      "initial name \"%s\"",
 				      netdev->ifindex, netdev->link);
-			continue;
+			goto clear_ifindices;
 		}
 
 		ret = netdev_deconf[netdev->type](handler, netdev);
 		if (ret < 0)
 			WARN("Failed to deconfigure network device");
 
 		if (netdev->type != LXC_NET_VETH)
-			continue;
+			goto clear_ifindices;
 
 		if (netdev->link[0] == '\0' || !is_ovs_bridge(netdev->link))
-			continue;
+			goto clear_ifindices;
 
 		if (netdev->priv.veth_attr.pair[0] != '\0')
 			hostveth = netdev->priv.veth_attr.pair;
 		else
 			hostveth = netdev->priv.veth_attr.veth1;
 		if (hostveth[0] == '\0')
-			continue;
+			goto clear_ifindices;
 
 		ret = lxc_delete_network_unpriv_exec(handler->lxcpath,
 						     handler->name, netdev,
 						     netns_path);
 		if (ret < 0) {
 			WARN("Failed to remove port \"%s\" from openvswitch "
 			     "bridge \"%s\"", hostveth, netdev->link);
-			continue;
+			goto clear_ifindices;
 		}
 		INFO("Removed interface \"%s\" from \"%s\"", hostveth,
 		     netdev->link);
+
+clear_ifindices:
+		/* We need to clear any ifindeces we recorded so liblxc won't
+		 * have cached stale data which would cause it to fail on reboot
+		 * we're we don't re-read the on-disk config file.
+		 */
+		netdev->ifindex = 0;
+		if (netdev->type == LXC_NET_PHYS) {
+			netdev->priv.phys_attr.ifindex = 0;
+		} else if (netdev->type == LXC_NET_VETH) {
+			netdev->priv.veth_attr.veth1[0] = '\0';
+			netdev->priv.veth_attr.ifindex = 0;
+		}
 	}
 
 	return true;
@@ -2496,7 +2509,7 @@ bool lxc_delete_network_priv(struct lxc_handler *handler)
 				      "\"%s\" to its initial name \"%s\"",
 				      netdev->ifindex, netdev->name,
 				      netdev->link);
-			continue;
+			goto clear_ifindices;
 		}
 
 		ret = netdev_deconf[netdev->type](handler, netdev);
@@ -2516,18 +2529,17 @@ bool lxc_delete_network_priv(struct lxc_handler *handler)
 			     netdev->ifindex);
 		} else if (ret < 0) {
 			WARN("Failed to remove interface \"%s\" with "
-			continue;
 			     "index %d: %s",
 			     netdev->name[0] != '\0' ? netdev->name : "(null)",
 			     netdev->ifindex, strerror(-ret));
-			     continue;
+			goto clear_ifindices;
 		}
 		INFO("Removed interface \"%s\" with index %d",
 		     netdev->name[0] != '\0' ? netdev->name : "(null)",
 		     netdev->ifindex);
 
 		if (netdev->type != LXC_NET_VETH)
-			continue;
+			goto clear_ifindices;
 
 		/* Explicitly delete host veth device to prevent lingering
 		 * devices. We had issues in LXD around this.
@@ -2537,19 +2549,21 @@ bool lxc_delete_network_priv(struct lxc_handler *handler)
 		else
 			hostveth = netdev->priv.veth_attr.veth1;
 		if (hostveth[0] == '\0')
-			continue;
+			goto clear_ifindices;
 
 		ret = lxc_netdev_delete_by_name(hostveth);
 		if (ret < 0) {
 			WARN("Failed to remove interface \"%s\" from \"%s\": %s",
 			     hostveth, netdev->link, strerror(-ret));
-			continue;
+			goto clear_ifindices;
 		}
 		INFO("Removed interface \"%s\" from \"%s\"", hostveth, netdev->link);
 
 		if (netdev->link[0] == '\0' || !is_ovs_bridge(netdev->link)) {
 			netdev->priv.veth_attr.veth1[0] = '\0';
-			continue;
+			netdev->ifindex = 0;
+			netdev->priv.veth_attr.ifindex = 0;
+			goto clear_ifindices;
 		}
 
 		/* Delete the openvswitch port. */
@@ -2561,7 +2575,18 @@ bool lxc_delete_network_priv(struct lxc_handler *handler)
 			INFO("Removed port \"%s\" from openvswitch bridge \"%s\"",
 			     hostveth, netdev->link);
 
-		netdev->priv.veth_attr.veth1[0] = '\0';
+clear_ifindices:
+		/* We need to clear any ifindeces we recorded so liblxc won't
+		 * have cached stale data which would cause it to fail on reboot
+		 * we're we don't re-read the on-disk config file.
+		 */
+		netdev->ifindex = 0;
+		if (netdev->type == LXC_NET_PHYS) {
+			netdev->priv.phys_attr.ifindex = 0;
+		} else if (netdev->type == LXC_NET_VETH) {
+			netdev->priv.veth_attr.veth1[0] = '\0';
+			netdev->priv.veth_attr.ifindex = 0;
+		}
 	}
 
 	return true;