From 729a06c41afaab419a70841b6749646e2f8fad1d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
Date: Fri, 1 Feb 2019 17:11:22 +0000
Subject: [PATCH] lxc, libxl: notify network driver of NICs during reconnect
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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: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 src/libxl/libxl_driver.c | 30 ++++++++++++++++++++++++++++++
 src/lxc/lxc_process.c    | 30 ++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 2b9c6f1866..e2819eb0cc 100644
--- a/src/libxl/libxl_driver.c
+++ b/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)) {
diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c
index de4d7c73fb..b59cbbaba5 100644
--- a/src/lxc/lxc_process.c
+++ b/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);