nwfilter: fix loadable module support

Following Daniel Berrange's multiple helpful suggestions for improving
this patch and introducing another driver interface, I now wrote the
below patch where the nwfilter driver registers the functions to
instantiate and teardown the nwfilters with a function in
conf/domain_nwfilter.c called virDomainConfNWFilterRegister. Previous
helper functions that were called from qemu_driver.c and qemu_conf.c
were move into conf/domain_nwfilter.h with slight renaming done for
consistency. Those functions now call the function expored by
domain_nwfilter.c, which in turn call the functions of the new driver
interface, if available.

src/Makefile.am

@@ -97,7 +97,8 @@ DRIVER_SOURCES =						\
 # Domain driver generic impl APIs
 DOMAIN_CONF_SOURCES =						\
 		conf/capabilities.c conf/capabilities.h		\
-		conf/domain_conf.c conf/domain_conf.h
+		conf/domain_conf.c conf/domain_conf.h		\
+		conf/domain_nwfilter.c conf/domain_nwfilter.h
 
 DOMAIN_EVENT_SOURCES =						\
 		conf/domain_event.c conf/domain_event.h

src/conf/domain_nwfilter.c

@@ -0,0 +1,61 @@
+/*
+ * domain_nwfilter.c:
+ *
+ * Copyright (C) 2010 IBM Corporation
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Stefan Berger <stefanb@us.ibm.com>
+ */
+
+#include <config.h>
+
+#include "internal.h"
+
+#include "datatypes.h"
+#include "domain_conf.h"
+#include "domain_nwfilter.h"
+
+static virDomainConfNWFilterDriverPtr nwfilterDriver;
+
+void
+virDomainConfNWFilterRegister(virDomainConfNWFilterDriverPtr driver) {
+    nwfilterDriver = driver;
+}
+
+int
+virDomainConfNWFilterInstantiate(virConnectPtr conn,
+                                 virDomainNetDefPtr net) {
+    if (nwfilterDriver != NULL)
+        return nwfilterDriver->instantiateFilter(conn, net);
+    /* driver module not available -- don't indicate failure */
+    return 0;
+}
+
+void
+virDomainConfNWFilterTeardown(virDomainNetDefPtr net) {
+    if (nwfilterDriver != NULL)
+        nwfilterDriver->teardownFilter(net);
+}
+
+void
+virDomainConfVMNWFilterTeardown(virDomainObjPtr vm) {
+    int i;
+
+    if (nwfilterDriver != NULL) {
+        for (i = 0; i < vm->def->nnets; i++)
+            virDomainConfNWFilterTeardown(vm->def->nets[i]);
+    }
+}

src/conf/domain_nwfilter.h

@@ -0,0 +1,43 @@
+/*
+ * domain_nwfilter.h:
+ *
+ * Copyright (C) 2010 IBM Corporation
+ * Copyright (C) 2010 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Stefan Berger <stefanb@us.ibm.com>
+ */
+#ifndef DOMAIN_NWFILTER_H
+# define DOMAIN_NWFILTER_H
+
+typedef int (*virDomainConfInstantiateNWFilter)(virConnectPtr conn,
+                                                virDomainNetDefPtr net);
+typedef void (*virDomainConfTeardownNWFilter)(virDomainNetDefPtr net);
+
+typedef struct {
+    virDomainConfInstantiateNWFilter instantiateFilter;
+    virDomainConfTeardownNWFilter    teardownFilter;
+} virDomainConfNWFilterDriver;
+typedef virDomainConfNWFilterDriver *virDomainConfNWFilterDriverPtr;
+
+void virDomainConfNWFilterRegister(virDomainConfNWFilterDriverPtr driver);
+
+int virDomainConfNWFilterInstantiate(virConnectPtr conn,
+                                     virDomainNetDefPtr net);
+void virDomainConfNWFilterTeardown(virDomainNetDefPtr net);
+void virDomainConfVMNWFilterTeardown(virDomainObjPtr vm);
+
+#endif /* DOMAIN_NWFILTER_H */

src/libvirt_private.syms

@@ -264,6 +264,11 @@ virDomainEventDispatchDefaultFunc;
 virDomainEventDispatch;
 virDomainEventQueueDispatch;
 
+# domain_nwfilter.h
+virDomainConfNWFilterRegister;
+virDomainConfNWFilterInstantiate;
+virDomainConfNWFilterTeardown;
+virDomainConfVMNWFilterTeardown;
 
 # ebtables.h
 ebtablesAddForwardAllowIn;

src/nwfilter/nwfilter_driver.c

@@ -33,6 +33,7 @@
 #include "datatypes.h"
 #include "memory.h"
 #include "domain_conf.h"
+#include "domain_nwfilter.h"
 #include "nwfilter_driver.h"
 #include "nwfilter_gentech_driver.h"
 
@@ -410,6 +411,20 @@ cleanup:
 }
 
 
+static int
+nwfilterInstantiateFilter(virConnectPtr conn,
+                          virDomainNetDefPtr net) {
+    return virNWFilterInstantiateFilter(conn, net);
+}
+
+
+static void
+nwfilterTeardownFilter(virDomainNetDefPtr net) {
+    if ((net->ifname) && (net->filter))
+        virNWFilterTeardownFilter(net);
+}
+
+
 static virNWFilterDriver nwfilterDriver = {
     .name = "nwfilter",
     .open = nwfilterOpen,
@@ -432,8 +447,16 @@ static virStateDriver stateDriver = {
     .active = nwfilterDriverActive,
 };
 
+
+static virDomainConfNWFilterDriver domainNWFilterDriver = {
+    .instantiateFilter = nwfilterInstantiateFilter,
+    .teardownFilter = nwfilterTeardownFilter,
+};
+
+
 int nwfilterRegister(void) {
     virRegisterNWFilterDriver(&nwfilterDriver);
     virRegisterStateDriver(&stateDriver);
+    virDomainConfNWFilterRegister(&domainNWFilterDriver);
     return 0;
 }

src/nwfilter/nwfilter_gentech_driver.h

@@ -67,21 +67,4 @@ void virNWFilterDomainFWUpdateCB(void *payload,
                                  const char *name ATTRIBUTE_UNUSED,
                                  void *data);
 
-
-/* tear down an interface's filter before tearing down the interface */
-static inline void
-virNWFilterTearNWFilter(virDomainNetDefPtr net) {
-    if ((net->filter) && (net->ifname))
-        virNWFilterTeardownFilter(net);
-}
-
-
-static inline void
-virNWFilterTearVMNWFilters(virDomainObjPtr vm) {
-    int i;
-
-    for (i = 0; i < vm->def->nnets; i++)
-        virNWFilterTearNWFilter(vm->def->nets[i]);
-}
-
 #endif

src/qemu/qemu_conf.c

@@ -54,7 +54,7 @@
 #include "network.h"
 #include "macvtap.h"
 #include "cpu/cpu.h"
-#include "nwfilter/nwfilter_gentech_driver.h"
+#include "domain_nwfilter.h"
 
 #define VIR_FROM_THIS VIR_FROM_QEMU
 
@@ -1514,9 +1514,10 @@ int qemudExtractVersion(struct qemud_driver *driver) {
 /**
  * qemudPhysIfaceConnect:
  * @conn: pointer to virConnect object
+ * @driver: pointer to the qemud_driver
  * @net: pointer to he VM's interface description with direct device type
- * @linkdev: The name of the physical interface to link the macvtap to
+ * @qemuCmdFlags: flags for qemu
- * @brmode: The mode to put the macvtap device into
+ * @vmuuid: The UUID of the VM (needed by 802.1Qbh)
  *
  * Returns a filedescriptor on success or -1 in case of error.
  */
@@ -1555,7 +1556,7 @@ qemudPhysIfaceConnect(virConnectPtr conn,
 
     if (rc >= 0) {
         if ((net->filter) && (net->ifname)) {
-            err = virNWFilterInstantiateFilter(conn, net);
+            err = virDomainConfNWFilterInstantiate(conn, net);
             if (err) {
                 close(rc);
                 rc = -1;
@@ -1688,7 +1689,7 @@ qemudNetworkIfaceConnect(virConnectPtr conn,
 
     if (tapfd >= 0) {
         if ((net->filter) && (net->ifname)) {
-            err = virNWFilterInstantiateFilter(conn, net);
+            err = virDomainConfNWFilterInstantiate(conn, net);
             if (err) {
                 close(tapfd);
                 tapfd = -1;
@@ -4207,7 +4208,7 @@ int qemudBuildCommandLine(virConnectPtr conn,
                     goto error;
 
                 if (VIR_REALLOC_N(*vmfds, (*nvmfds)+1) < 0) {
-                    virNWFilterTearNWFilter(net);
+                    virDomainConfNWFilterTeardown(net);
                     close(tapfd);
                     goto no_memory;
                 }
@@ -4226,7 +4227,7 @@ int qemudBuildCommandLine(virConnectPtr conn,
                     goto error;
 
                 if (VIR_REALLOC_N(*vmfds, (*nvmfds)+1) < 0) {
-                    virNWFilterTearNWFilter(net);
+                    virDomainConfNWFilterTeardown(net);
                     close(tapfd);
                     goto no_memory;
                 }
@@ -4766,7 +4767,7 @@ int qemudBuildCommandLine(virConnectPtr conn,
     virReportOOMError();
  error:
     for (i = 0; i <= last_good_net; i++)
-        virNWFilterTearNWFilter(def->nets[i]);
+        virDomainConfNWFilterTeardown(def->nets[i]);
     if (vmfds &&
         *vmfds) {
         for (i = 0; i < *nvmfds; i++)

src/qemu/qemu_driver.c

@@ -81,7 +81,7 @@
 #include "xml.h"
 #include "cpu/cpu.h"
 #include "macvtap.h"
-#include "nwfilter/nwfilter_gentech_driver.h"
+#include "domain_nwfilter.h"
 #include "hooks.h"
 #include "storage_file.h"
 
@@ -3577,7 +3577,7 @@ static int qemudStartVMDaemon(virConnectPtr conn,
     VIR_FREE(progenv);
 
     if (ret == -1) /* The VM failed to start; tear filters before taps */
-        virNWFilterTearVMNWFilters(vm);
+        virDomainConfVMNWFilterTeardown(vm);
 
     if (vmfds) {
         for (i = 0 ; i < nvmfds ; i++) {
@@ -3669,7 +3669,7 @@ static void qemudShutdownVMDaemon(struct qemud_driver *driver,
      * reporting so we don't squash a legit error. */
     orig_err = virSaveLastError();
 
-    virNWFilterTearVMNWFilters(vm);
+    virDomainConfVMNWFilterTeardown(vm);
 
     if (driver->macFilter) {
         def = vm->def;
@@ -7646,7 +7646,7 @@ cleanup:
         VIR_WARN0("Unable to release PCI address on NIC");
 
     if (ret != 0)
-        virNWFilterTearNWFilter(net);
+        virDomainConfNWFilterTeardown(net);
 
     VIR_FREE(nicstr);
     VIR_FREE(netstr);
@@ -8615,7 +8615,7 @@ qemudDomainDetachNetDevice(struct qemud_driver *driver,
     }
     qemuDomainObjExitMonitorWithDriver(driver, vm);
 
-    virNWFilterTearNWFilter(detach);
+    virDomainConfNWFilterTeardown(detach);
 
 #if WITH_MACVTAP
     if (detach->type == VIR_DOMAIN_NET_TYPE_DIRECT) {