lxc, libxl: notify network driver of NICs during reconnect

When starting up it is important to notify the network driver of any
NICs which are used by running guests so that it can account for any
resources they are using.
Reviewed-by: NLaine Stump <laine@laine.org>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/libxl/libxl_driver.c

@@ -352,6 +352,34 @@ libxlAutostartDomain(virDomainObjPtr vm,
     return ret;
 }
 
+
+static void
+libxlReconnectNotifyNets(virDomainDefPtr def)
+{
+    size_t i;
+    virConnectPtr conn = NULL;
+
+    for (i = 0; i < def->nnets; i++) {
+        virDomainNetDefPtr net = def->nets[i];
+        /* keep others from trying to use the macvtap device name, but
+         * don't return error if this happens, since that causes the
+         * domain to be unceremoniously killed, which would be *very*
+         * impolite.
+         */
+        if (virDomainNetGetActualType(net) == VIR_DOMAIN_NET_TYPE_DIRECT)
+           ignore_value(virNetDevMacVLanReserveName(net->ifname, false));
+
+        if (net->type == VIR_DOMAIN_NET_TYPE_NETWORK) {
+            if (!conn && !(conn = virGetConnectNetwork()))
+                continue;
+            virDomainNetNotifyActualDevice(conn, def, net);
+        }
+    }
+
+    virObjectUnref(conn);
+}
+
+
 /*
  * Reconnect to running domains that were previously started/created
  * with libxenlight driver.
@@ -424,6 +452,8 @@ libxlReconnectDomain(virDomainObjPtr vm,
     /* Enable domain death events */
     libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW);
 
+    libxlReconnectNotifyNets(vm->def);
+
     /* now that we know it's reconnected call the hook if present */
     if (virHookPresent(VIR_HOOK_DRIVER_LIBXL) &&
         STRNEQ("Domain-0", vm->def->name)) {

src/lxc/lxc_process.c

@@ -1646,6 +1646,34 @@ virLXCProcessAutostartAll(virLXCDriverPtr driver)
     virObjectUnref(conn);
 }
 
+
+static void
+virLXCProcessReconnectNotifyNets(virDomainDefPtr def)
+{
+    size_t i;
+    virConnectPtr conn = NULL;
+
+    for (i = 0; i < def->nnets; i++) {
+        virDomainNetDefPtr net = def->nets[i];
+        /* keep others from trying to use the macvtap device name, but
+         * don't return error if this happens, since that causes the
+         * domain to be unceremoniously killed, which would be *very*
+         * impolite.
+         */
+        if (virDomainNetGetActualType(net) == VIR_DOMAIN_NET_TYPE_DIRECT)
+           ignore_value(virNetDevMacVLanReserveName(net->ifname, false));
+
+        if (net->type == VIR_DOMAIN_NET_TYPE_NETWORK) {
+            if (!conn && !(conn = virGetConnectNetwork()))
+                continue;
+            virDomainNetNotifyActualDevice(conn, def, net);
+        }
+    }
+
+    virObjectUnref(conn);
+}
+
+
 static int
 virLXCProcessReconnectDomain(virDomainObjPtr vm,
                              void *opaque)
@@ -1692,6 +1720,8 @@ virLXCProcessReconnectDomain(virDomainObjPtr vm,
                                            vm->def, vm->pid) < 0)
             goto error;
 
+        virLXCProcessReconnectNotifyNets(vm->def);
+
         /* now that we know it's reconnected call the hook if present */
         if (virHookPresent(VIR_HOOK_DRIVER_LXC)) {
             char *xml = virDomainDefFormat(vm->def, driver->caps, 0);