qemu : support persistent add/delete network interface

This patch allows to modify interfaces of domain(qemu)
* src/conf/domain_conf.c src/conf/domain_conf.h src/libvirt_private.syms:
  (virDomainNetInsert)     : Insert a network device to domain definition.
  (virDomainNetIndexByMac) : Returns an index of net device in array.
  (virDomainNetRemoveByMac): Remove a NIC of passed MAC address.
* src/qemu/qemu_driver.c
  (qemuDomainAttachDeviceConfig): add codes for NIC.
  (qemuDomainDetachDeviceConfig): add codes for NIC.

src/conf/domain_conf.c

@@ -5204,6 +5204,51 @@ int virDomainDiskRemoveByName(virDomainDefPtr def, const char *name)
     return 0;
 }
 
+int virDomainNetInsert(virDomainDefPtr def, virDomainNetDefPtr net)
+{
+    if (VIR_REALLOC_N(def->nets, def->nnets + 1) < 0)
+        return -1;
+    def->nets[def->nnets]  = net;
+    def->nnets++;
+    return 0;
+}
+
+int virDomainNetIndexByMac(virDomainDefPtr def, const unsigned char *mac)
+{
+    int i;
+
+    for (i = 0; i < def->nnets; i++)
+        if (!memcmp(def->nets[i]->mac, mac, VIR_MAC_BUFLEN))
+            return i;
+    return -1;
+}
+
+static void virDomainNetRemove(virDomainDefPtr def, size_t i)
+{
+    if (def->nnets > 1) {
+        memmove(def->nets + i,
+                def->nets + i + 1,
+                sizeof(*def->nets) * (def->nnets - (i + 1)));
+        def->nnets--;
+        if (VIR_REALLOC_N(def->nets, def->nnets) < 0) {
+            /* ignore harmless */
+        }
+    } else {
+        VIR_FREE(def->nets);
+        def->nnets = 0;
+    }
+}
+
+int virDomainNetRemoveByMac(virDomainDefPtr def, const unsigned char *mac)
+{
+    int i = virDomainNetIndexByMac(def, mac);
+
+    if (i < 0)
+        return -1;
+    virDomainNetRemove(def, i);
+    return 0;
+}
+
 
 int virDomainControllerInsert(virDomainDefPtr def,
                               virDomainControllerDefPtr controller)

src/conf/domain_conf.h

@@ -1370,6 +1370,10 @@ int virDomainDiskDefAssignAddress(virCapsPtr caps, virDomainDiskDefPtr def);
 void virDomainDiskRemove(virDomainDefPtr def, size_t i);
 int virDomainDiskRemoveByName(virDomainDefPtr def, const char *name);
 
+int virDomainNetIndexByMac(virDomainDefPtr def, const unsigned char *mac);
+int virDomainNetInsert(virDomainDefPtr def, virDomainNetDefPtr net);
+int virDomainNetRemoveByMac(virDomainDefPtr def, const unsigned char *mac);
+
 int virDomainControllerInsert(virDomainDefPtr def,
                               virDomainControllerDefPtr controller);
 void virDomainControllerInsertPreAlloced(virDomainDefPtr def,

src/libvirt_private.syms

@@ -292,6 +292,9 @@ virDomainLoadAllConfigs;
 virDomainMemballoonModelTypeFromString;
 virDomainMemballoonModelTypeToString;
 virDomainNetDefFree;
+virDomainNetIndexByMac;
+virDomainNetInsert;
+virDomainNetRemoveByMac;
 virDomainNetTypeToString;
 virDomainObjAssignDef;
 virDomainObjCopyPersistentDef;

src/qemu/qemu_driver.c

@@ -4255,6 +4255,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
                              virDomainDeviceDefPtr dev)
 {
     virDomainDiskDefPtr disk;
+    virDomainNetDefPtr net;
 
     switch (dev->type) {
     case VIR_DOMAIN_DEVICE_DISK:
@@ -4277,6 +4278,23 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
             return -1;
         break;
 
+    case VIR_DOMAIN_DEVICE_NET:
+        net = dev->data.net;
+        if (virDomainNetIndexByMac(vmdef, net->mac) >= 0) {
+            char macbuf[VIR_MAC_STRING_BUFLEN];
+            virFormatMacAddr(net->mac, macbuf);
+            qemuReportError(VIR_ERR_INVALID_ARG,
+                            _("mac %s already exists"), macbuf);
+            return -1;
+        }
+        if (virDomainNetInsert(vmdef, net)) {
+            virReportOOMError();
+            return -1;
+        }
+        dev->data.net = NULL;
+        if (qemuDomainAssignPCIAddresses(vmdef) < 0)
+            return -1;
+        break;
     default:
          qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                          _("persistent attach of device is not supported"));
@@ -4291,6 +4309,7 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
                              virDomainDeviceDefPtr dev)
 {
     virDomainDiskDefPtr disk;
+    virDomainNetDefPtr net;
 
     switch (dev->type) {
     case VIR_DOMAIN_DEVICE_DISK:
@@ -4301,6 +4320,17 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
             return -1;
         }
         break;
+    case VIR_DOMAIN_DEVICE_NET:
+        net = dev->data.net;
+        if (virDomainNetRemoveByMac(vmdef, net->mac)) {
+            char macbuf[VIR_MAC_STRING_BUFLEN];
+
+            virFormatMacAddr(net->mac, macbuf);
+            qemuReportError(VIR_ERR_INVALID_ARG,
+                            _("no nic of mac %s"), macbuf);
+            return -1;
+        }
+        break;
     default:
         qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                         _("persistent detach of device is not supported"));