[ovs-dev] [mcgroup 2/4] datapath: Hardcode vport multicast group ID on older kernels.

[Ethan Jackson]

Older kernels do not advertise the multicast groups of families
when requested by userspace.  As a workaround, this patch hardcodes
the multicast group ID of the ovs_vport family on these kernels.
Userspace will be able to fall back to this hardcoded value if the
standard mechanism is unavailable.

Signed-off-by: Ethan Jackson <ethan at nicira.com>
---

My bad, the revised patch I sent out didn't actually work.  This one has been
tested and as the updated ID value.

---
 datapath/linux/compat/genetlink.inc   |   11 +++++++-
 include/openvswitch/automake.mk       |    1 +
 include/openvswitch/datapath-compat.h |   45 +++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+), 1 deletions(-)
 create mode 100644 include/openvswitch/datapath-compat.h

diff --git a/datapath/linux/compat/genetlink.inc b/datapath/linux/compat/genetlink.inc
index d381e4f..9e7d90d 100644
--- a/datapath/linux/compat/genetlink.inc
+++ b/datapath/linux/compat/genetlink.inc
@@ -6,6 +6,9 @@
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
 #include <linux/mutex.h>
 
+#include "openvswitch/datapath-compat.h"
+#include "openvswitch/datapath-protocol.h"
+
 static DEFINE_MUTEX(mc_group_mutex);
 
 int genl_register_mc_group(struct genl_family *family,
@@ -13,9 +16,15 @@ int genl_register_mc_group(struct genl_family *family,
 {
 	static int next_group = GENL_FIRST_MCGROUP;
 
+	grp->family = family;
+
+	if (!strcmp(grp->name, OVS_VPORT_MCGROUP)) {
+		grp->id = OVS_VPORT_MCGROUP_FALLBACK_ID;
+		return 0;
+	}
+
 	mutex_lock(&mc_group_mutex);
 	grp->id = next_group;
-	grp->family = family;
 
 	if (++next_group > GENL_LAST_MCGROUP)
 		next_group = GENL_FIRST_MCGROUP;
diff --git a/include/openvswitch/automake.mk b/include/openvswitch/automake.mk
index b7c6723..24a6826 100644
--- a/include/openvswitch/automake.mk
+++ b/include/openvswitch/automake.mk
@@ -1,5 +1,6 @@
 noinst_HEADERS += \
 	include/openvswitch/brcompat-netlink.h \
+	include/openvswitch/datapath-compat.h \
 	include/openvswitch/datapath-protocol.h \
 	include/openvswitch/tunnel.h \
 	include/openvswitch/types.h
diff --git a/include/openvswitch/datapath-compat.h b/include/openvswitch/datapath-compat.h
new file mode 100644
index 0000000..cf0e519
--- /dev/null
+++ b/include/openvswitch/datapath-compat.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2011 Nicira Networks.
+ *
+ * This file is offered under your choice of two licenses: Apache 2.0 or GNU
+ * GPL 2.0 or later.  The permission statements for each of these licenses is
+ * given below.  You may license your modifications to this file under either
+ * of these licenses or both.  If you wish to license your modifications under
+ * only one of these licenses, delete the permission text for the other
+ * license.
+ *
+ * ----------------------------------------------------------------------
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ----------------------------------------------------------------------
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * ----------------------------------------------------------------------
+ */
+
+#ifndef OPENVSWITCH_DATAPATH_COMPAT_H
+#define OPENVSWITCH_DATAPATH_COMPAT_H 1
+
+#define OVS_VPORT_MCGROUP_FALLBACK_ID 33
+
+#endif /* openvswitch/datapath-compat.h */
-- 
1.7.6.1