[ovs-dev] [PATCH 2/2] ovs: add brcompat module into kernel

Tony Zelenoff antonz at parallels.com
Tue Jun 26 12:54:45 UTC 2012


Signed-off-by: Tony Zelenoff <antonz at parallels.com>
---
 net/openvswitch/Makefile      |    1 +
 net/openvswitch/brcompat-nl.h |  100 +++++++
 net/openvswitch/ovs-brcompat.c|  567 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 668 insertions(+), 0 deletions(-)
 create mode 100644 net/openvswitch/brcompat-nl.h
 create mode 100644 net/openvswitch/ovs-brcompat.c

diff --git a/net/openvswitch/Makefile b/net/openvswitch/Makefile
index 15e7384..084b43a 100644
--- a/net/openvswitch/Makefile
+++ b/net/openvswitch/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_OPENVSWITCH) += openvswitch.o
+obj-$(CONFIG_OVS_BRCOMPAT) += ovs-brcompat.o
 
 openvswitch-y := \
 	actions.o \
diff --git a/net/openvswitch/brcompat-nl.h b/net/openvswitch/brcompat-nl.h
new file mode 100644
index 0000000..d238a16
--- /dev/null
+++ b/net/openvswitch/brcompat-nl.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2008, 2009, 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_BRCOMPAT_NETLINK_H
+#define OPENVSWITCH_BRCOMPAT_NETLINK_H 1
+
+#define BRC_GENL_FAMILY_NAME "brcompat"
+
+/* Attributes that can be attached to the datapath's netlink messages. */
+enum {
+	BRC_GENL_A_UNSPEC,
+
+	/*
+	 * "K:" attributes appear in messages from the kernel to userspace.
+	 * "U:" attributes appear in messages from userspace to the kernel.
+	 */
+
+	/* BRC_GENL_C_DP_ADD, BRC_GENL_C_DP_DEL. */
+	BRC_GENL_A_DP_NAME,		/* K: Datapath name. */
+
+	/* BRC_GENL_C_DP_ADD, BRC_GENL_C_DP_DEL,
+	   BRC_GENL_C_PORT_ADD, BRC_GENL_C_PORT_DEL. */
+	BRC_GENL_A_PORT_NAME,	/* K: Interface name. */
+
+	/* BRC_GENL_C_DP_RESULT. */
+	BRC_GENL_A_ERR_CODE,	/* U: Positive error code. */
+
+	/* BRC_GENL_C_QUERY_MC. */
+	BRC_GENL_A_MC_GROUP,	/* K: Generic netlink multicast group. */
+
+	/* BRC_GENL_C_FDB_QUERY. */
+	BRC_GENL_A_FDB_COUNT,	/* K: Number of FDB entries to read. */
+	BRC_GENL_A_FDB_SKIP,	/* K: Record offset into FDB to start reading. */
+
+	/* BRC_GENL_C_DP_RESULT. */
+	BRC_GENL_A_FDB_DATA,    /* U: FDB records. */
+	BRC_GENL_A_IFINDEXES,   /* U: "int" ifindexes of bridges or ports. */
+
+	__BRC_GENL_A_MAX,
+	BRC_GENL_A_MAX = __BRC_GENL_A_MAX - 1
+};
+
+/* Commands that can be executed on the datapath's netlink interface. */
+enum brc_genl_command {
+	BRC_GENL_C_UNSPEC,
+
+	/*
+	 * "K:" messages are sent by the kernel to userspace.
+	 * "U:" messages are sent by userspace to the kernel.
+	 */
+	BRC_GENL_C_DP_ADD,		/* K: Datapath created. */
+	BRC_GENL_C_DP_DEL,		/* K: Datapath destroyed. */
+	BRC_GENL_C_DP_RESULT,	/* U: Return code from ovs-brcompatd. */
+	BRC_GENL_C_PORT_ADD,	/* K: Port added to datapath. */
+	BRC_GENL_C_PORT_DEL,	/* K: Port removed from datapath. */
+	BRC_GENL_C_QUERY_MC,	/* U: Get multicast group for brcompat. */
+	BRC_GENL_C_FDB_QUERY,	/* K: Read records from forwarding database. */
+	BRC_GENL_C_GET_BRIDGES, /* K: Get ifindexes of all bridges. */
+	BRC_GENL_C_GET_PORTS,   /* K: Get ifindexes of all ports on a bridge. */
+
+	__BRC_GENL_C_MAX,
+	BRC_GENL_C_MAX = __BRC_GENL_C_MAX - 1
+};
+#endif /* openvswitch/brcompat-netlink.h */
diff --git a/net/openvswitch/ovs-brcompat.c b/net/openvswitch/ovs-brcompat.c
new file mode 100644
index 0000000..414b952
--- /dev/null
+++ b/net/openvswitch/ovs-brcompat.c
@@ -0,0 +1,567 @@
+/*
+ * Copyright (c) 2007-2012 Nicira Networks.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * 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
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/completion.h>
+#include <linux/etherdevice.h>
+#include <linux/if_bridge.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/genetlink.h>
+
+#include "brcompat-nl.h"
+#include "datapath.h"
+
+static struct genl_family brc_genl_family;
+static struct genl_multicast_group brc_mc_group;
+
+/* Time to wait for ovs-vswitchd to respond to a datapath action, in
+ * jiffies. */
+#define BRC_TIMEOUT (HZ * 5)
+
+/* Mutex to serialize ovs-brcompatd callbacks.  (Some callbacks naturally hold
+ * br_ioctl_mutex, others hold rtnl_lock, but we can't take the former
+ * ourselves and we don't want to hold the latter over a potentially long
+ * period of time.) */
+static DEFINE_MUTEX(brc_serial);
+
+/* Userspace communication. */
+static DEFINE_SPINLOCK(brc_lock);    /* Ensure atomic access to these vars. */
+static DECLARE_COMPLETION(brc_done); /* Userspace signaled operation done? */
+static struct sk_buff *brc_reply;    /* Reply from userspace. */
+static u32 brc_seq;		     /* Sequence number for current op. */
+
+static struct sk_buff *brc_send_command(struct net *,
+					struct sk_buff *,
+					struct nlattr **attrs);
+static int brc_send_simple_command(struct net *, struct sk_buff *);
+
+static struct sk_buff *brc_make_request(int op, const char *bridge,
+					const char *port)
+{
+	struct sk_buff *skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!skb)
+		goto error;
+
+	genlmsg_put(skb, 0, 0, &brc_genl_family, 0, op);
+	if (bridge && (nla_put_string(skb, BRC_GENL_A_DP_NAME, bridge) < 0))
+		goto fail;
+
+	if (port && nla_put_string(skb, BRC_GENL_A_PORT_NAME, port) < 0)
+		goto fail;
+
+	return skb;
+fail:
+	kfree_skb(skb);
+error:
+	return NULL;
+}
+
+static int brc_send_simple_command(struct net *net, struct sk_buff *request)
+{
+	struct nlattr *attrs[BRC_GENL_A_MAX + 1];
+	struct sk_buff *reply;
+	int error;
+
+	reply = brc_send_command(net, request, attrs);
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+
+	error = nla_get_u32(attrs[BRC_GENL_A_ERR_CODE]);
+	kfree_skb(reply);
+	return -error;
+}
+
+static int brc_add_del_bridge(struct net *net, char __user *uname, int add)
+{
+	struct sk_buff *request;
+	char name[IFNAMSIZ];
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(name, uname, IFNAMSIZ))
+		return -EFAULT;
+
+	name[IFNAMSIZ - 1] = 0;
+	request = brc_make_request(add ? BRC_GENL_C_DP_ADD : BRC_GENL_C_DP_DEL,
+				   name, NULL);
+	if (!request)
+		return -ENOMEM;
+
+	return brc_send_simple_command(net, request);
+}
+
+static int brc_get_indices(struct net *net,
+			   int op, const char *br_name,
+			   int __user *uindices, int n)
+{
+	struct nlattr *attrs[BRC_GENL_A_MAX + 1];
+	struct sk_buff *request, *reply;
+	int *indices;
+	int ret;
+	int len;
+
+	if (n < 0)
+		return -EINVAL;
+	if (n >= 2048)
+		return -ENOMEM;
+
+	request = brc_make_request(op, br_name, NULL);
+	if (!request)
+		return -ENOMEM;
+
+	reply = brc_send_command(net, request, attrs);
+	ret = PTR_ERR(reply);
+	if (IS_ERR(reply))
+		goto exit;
+
+	ret = -nla_get_u32(attrs[BRC_GENL_A_ERR_CODE]);
+	if (ret < 0)
+		goto exit_free_skb;
+
+	ret = -EINVAL;
+	if (!attrs[BRC_GENL_A_IFINDEXES])
+		goto exit_free_skb;
+
+	len = nla_len(attrs[BRC_GENL_A_IFINDEXES]);
+	indices = nla_data(attrs[BRC_GENL_A_IFINDEXES]);
+	if (len % sizeof(int))
+		goto exit_free_skb;
+
+	n = min_t(int, n, len / sizeof(int));
+	ret = copy_to_user(uindices, indices, n * sizeof(int)) ? -EFAULT : n;
+
+exit_free_skb:
+	kfree_skb(reply);
+exit:
+	return ret;
+}
+
+/* Called with br_ioctl_mutex. */
+static int brc_get_bridges(struct net *net, int __user *uindices, int n)
+{
+	return brc_get_indices(net, BRC_GENL_C_GET_BRIDGES, NULL, uindices, n);
+}
+
+/* Legacy deviceless bridge ioctl's.  Called with br_ioctl_mutex. */
+static int old_deviceless(struct net *net, void __user *uarg)
+{
+	unsigned long args[3];
+
+	if (copy_from_user(args, uarg, sizeof(args)))
+		return -EFAULT;
+
+	switch (args[0]) {
+	case BRCTL_GET_BRIDGES:
+		return brc_get_bridges(net, (int __user *)args[1], args[2]);
+
+	case BRCTL_ADD_BRIDGE:
+		return brc_add_del_bridge(net, (void __user *)args[1], 1);
+	case BRCTL_DEL_BRIDGE:
+		return brc_add_del_bridge(net, (void __user *)args[1], 0);
+	}
+
+	return -EOPNOTSUPP;
+}
+
+/* Called with the br_ioctl_mutex. */
+static int brc_ioctl_deviceless_stub(struct net *net, unsigned int cmd,
+				     void __user *uarg)
+{
+	switch (cmd) {
+	case SIOCGIFBR:
+	case SIOCSIFBR:
+		return old_deviceless(net, uarg);
+
+	case SIOCBRADDBR:
+		return brc_add_del_bridge(net, uarg, 1);
+	case SIOCBRDELBR:
+		return brc_add_del_bridge(net, uarg, 0);
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int brc_add_del_port(struct net_device *dev, int port_ifindex, int add)
+{
+	struct sk_buff *request;
+	struct net_device *port;
+	int err;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	port = __dev_get_by_index(dev_net(dev), port_ifindex);
+	if (!port)
+		return -EINVAL;
+
+	/* Save name of dev and port because there's a race between the
+	 * rtnl_unlock() and the brc_send_simple_command(). */
+	request = brc_make_request(add ? BRC_GENL_C_PORT_ADD : BRC_GENL_C_PORT_DEL,
+				   dev->name, port->name);
+	if (!request)
+		return -ENOMEM;
+
+	rtnl_unlock();
+	err = brc_send_simple_command(dev_net(dev), request);
+	rtnl_lock();
+
+	return err;
+}
+
+static int brc_get_bridge_info(struct net_device *dev,
+			       struct __bridge_info __user *ub)
+{
+	struct __bridge_info b;
+
+	memset(&b, 0, sizeof(struct __bridge_info));
+
+	/* First two bytes are the priority, which we should skip.  This comes
+	 * from struct bridge_id in br_private.h, which is unavailable to us.
+	 */
+	memcpy((u8 *)&b.bridge_id + 2, dev->dev_addr, ETH_ALEN);
+	b.stp_enabled = 0;
+
+	if (copy_to_user(ub, &b, sizeof(struct __bridge_info)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int brc_get_port_list(struct net_device *dev, int __user *uindices,
+			     int num)
+{
+	int retval;
+
+	rtnl_unlock();
+	retval = brc_get_indices(dev_net(dev), BRC_GENL_C_GET_PORTS, dev->name,
+				 uindices, num);
+	rtnl_lock();
+
+	return retval;
+}
+
+/*
+ * Format up to a page worth of forwarding table entries
+ * userbuf -- where to copy result
+ * maxnum  -- maximum number of entries desired
+ *            (limited to a page for sanity)
+ * offset  -- number of records to skip
+ */
+static int brc_get_fdb_entries(struct net_device *dev, void __user *userbuf,
+			       unsigned long maxnum, unsigned long offset)
+{
+	struct nlattr *attrs[BRC_GENL_A_MAX + 1];
+	struct sk_buff *request, *reply;
+	int retval;
+	int len;
+
+	/* Clamp size to PAGE_SIZE, test maxnum to avoid overflow */
+	if (maxnum > PAGE_SIZE/sizeof(struct __fdb_entry))
+		maxnum = PAGE_SIZE/sizeof(struct __fdb_entry);
+
+	request = brc_make_request(BRC_GENL_C_FDB_QUERY, dev->name, NULL);
+	if (!request)
+		return -ENOMEM;
+	if (nla_put_u64(request, BRC_GENL_A_FDB_COUNT, maxnum) < 0)
+		goto fail;
+
+	if (nla_put_u64(request, BRC_GENL_A_FDB_SKIP, offset) < 0)
+		goto fail;
+
+	rtnl_unlock();
+	reply = brc_send_command(dev_net(dev), request, attrs);
+	retval = PTR_ERR(reply);
+	if (IS_ERR(reply))
+		goto exit;
+
+	retval = -nla_get_u32(attrs[BRC_GENL_A_ERR_CODE]);
+	if (retval < 0)
+		goto exit_free_skb;
+
+	retval = -EINVAL;
+	if (!attrs[BRC_GENL_A_FDB_DATA])
+		goto exit_free_skb;
+	len = nla_len(attrs[BRC_GENL_A_FDB_DATA]);
+	if (len % sizeof(struct __fdb_entry) ||
+	    len / sizeof(struct __fdb_entry) > maxnum)
+		goto exit_free_skb;
+
+	retval = len / sizeof(struct __fdb_entry);
+	if (copy_to_user(userbuf, nla_data(attrs[BRC_GENL_A_FDB_DATA]), len))
+		retval = -EFAULT;
+
+exit_free_skb:
+	kfree_skb(reply);
+exit:
+	rtnl_lock();
+	return retval;
+
+fail:
+	kfree_skb(request);
+	return -ENOMEM;
+}
+
+/* Legacy ioctl's through SIOCDEVPRIVATE.  Called with rtnl_lock. */
+static int old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
+{
+	unsigned long args[4];
+
+	if (copy_from_user(args, rq->ifr_data, sizeof(args)))
+		return -EFAULT;
+
+	switch (args[0]) {
+	case BRCTL_ADD_IF:
+		return brc_add_del_port(dev, args[1], 1);
+	case BRCTL_DEL_IF:
+		return brc_add_del_port(dev, args[1], 0);
+
+	case BRCTL_GET_BRIDGE_INFO:
+		return brc_get_bridge_info(dev, (struct __bridge_info __user *)args[1]);
+
+	case BRCTL_GET_PORT_LIST:
+		return brc_get_port_list(dev, (int __user *)args[1], args[2]);
+
+	case BRCTL_GET_FDB_ENTRIES:
+		return brc_get_fdb_entries(dev, (void __user *)args[1],
+					   args[2], args[3]);
+	}
+
+	return -EOPNOTSUPP;
+}
+
+/* Called with the rtnl_lock. */
+static int brc_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
+{
+	int err;
+
+	switch (cmd) {
+	case SIOCDEVPRIVATE:
+		err = old_dev_ioctl(dev, rq, cmd);
+		break;
+
+	case SIOCBRADDIF:
+		return brc_add_del_port(dev, rq->ifr_ifindex, 1);
+	case SIOCBRDELIF:
+		return brc_add_del_port(dev, rq->ifr_ifindex, 0);
+
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+
+	return err;
+}
+
+
+static struct genl_family brc_genl_family = {
+	.id = GENL_ID_GENERATE,
+	.hdrsize = 0,
+	.name = BRC_GENL_FAMILY_NAME,
+	.version = 1,
+	.maxattr = BRC_GENL_A_MAX,
+	.netnsok = true,
+};
+
+static int brc_genl_query(struct sk_buff *skb, struct genl_info *info)
+{
+	int err = -EINVAL;
+	struct sk_buff *ans_skb;
+	void *data;
+
+	ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!ans_skb)
+		return -ENOMEM;
+
+	data = genlmsg_put_reply(ans_skb, info, &brc_genl_family,
+				 0, BRC_GENL_C_QUERY_MC);
+	if (data == NULL) {
+		err = -ENOMEM;
+		goto err;
+	}
+	if (nla_put_u32(ans_skb, BRC_GENL_A_MC_GROUP, brc_mc_group.id) < 0)
+		goto err;
+
+	genlmsg_end(ans_skb, data);
+	return genlmsg_reply(ans_skb, info);
+
+err:
+	kfree_skb(ans_skb);
+	return err;
+}
+
+/* Attribute policy: what each attribute may contain.  */
+static struct nla_policy brc_genl_policy[BRC_GENL_A_MAX + 1] = {
+	[BRC_GENL_A_ERR_CODE] = { .type = NLA_U32 },
+	[BRC_GENL_A_FDB_DATA] = { .type = NLA_UNSPEC },
+};
+
+static int brc_genl_dp_result(struct sk_buff *skb, struct genl_info *info)
+{
+	unsigned long int flags;
+	int err;
+
+	if (!info->attrs[BRC_GENL_A_ERR_CODE])
+		return -EINVAL;
+
+	skb = skb_clone(skb, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	spin_lock_irqsave(&brc_lock, flags);
+	if (brc_seq == info->snd_seq) {
+		brc_seq++;
+
+		kfree_skb(brc_reply);
+		brc_reply = skb;
+
+		complete(&brc_done);
+		err = 0;
+	} else {
+		kfree_skb(skb);
+		err = -ESTALE;
+	}
+	spin_unlock_irqrestore(&brc_lock, flags);
+
+	return err;
+}
+
+static struct genl_ops brc_genl_ops[] = {
+	{ .cmd = BRC_GENL_C_QUERY_MC,
+	  .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privelege. */
+	  .policy = NULL,
+	  .doit = brc_genl_query,
+	},
+	{ .cmd = BRC_GENL_C_DP_RESULT,
+	  .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privelege. */
+	  .policy = brc_genl_policy,
+	  .doit = brc_genl_dp_result,
+	},
+};
+
+static struct sk_buff *brc_send_command(struct net *net,
+					struct sk_buff *request,
+					struct nlattr **attrs)
+{
+	unsigned long int flags;
+	struct sk_buff *reply;
+	int error;
+
+	mutex_lock(&brc_serial);
+
+	/* Increment sequence number first, so that we ignore any replies
+	 * to stale requests. */
+	spin_lock_irqsave(&brc_lock, flags);
+	nlmsg_hdr(request)->nlmsg_seq = ++brc_seq;
+	INIT_COMPLETION(brc_done);
+	spin_unlock_irqrestore(&brc_lock, flags);
+
+	nlmsg_end(request, nlmsg_hdr(request));
+
+	/* Send message. */
+	error = genlmsg_multicast_netns(net, request, 0,
+					brc_mc_group.id, GFP_KERNEL);
+	if (error < 0)
+		goto error;
+
+	/* Wait for reply. */
+	error = -ETIMEDOUT;
+	if (!wait_for_completion_timeout(&brc_done, BRC_TIMEOUT)) {
+		pr_warn("timed out waiting for userspace\n");
+		goto error;
+	}
+
+	/* Grab reply. */
+	spin_lock_irqsave(&brc_lock, flags);
+	reply = brc_reply;
+	brc_reply = NULL;
+	spin_unlock_irqrestore(&brc_lock, flags);
+
+	mutex_unlock(&brc_serial);
+
+	/* Re-parse message.  Can't fail, since it parsed correctly once
+	 * already. */
+	error = nlmsg_parse(nlmsg_hdr(reply), GENL_HDRLEN,
+			    attrs, BRC_GENL_A_MAX, brc_genl_policy);
+	WARN_ON(error);
+
+	return reply;
+
+error:
+	mutex_unlock(&brc_serial);
+	return ERR_PTR(error);
+}
+
+static int __init brc_init(void)
+{
+	int err;
+
+	pr_info("Open vSwitch Bridge Compatibility, built "__DATE__" "__TIME__"\n");
+
+	/* Set the bridge ioctl handler */
+	brioctl_set(brc_ioctl_deviceless_stub);
+
+	/* Set the openvswitch_mod device ioctl handler */
+	ovs_dp_ioctl_hook = brc_dev_ioctl;
+
+	/* Randomize the initial sequence number.  This is not a security
+	 * feature; it only helps avoid crossed wires between userspace and
+	 * the kernel when the module is unloaded and reloaded. */
+	brc_seq = net_random();
+
+	/* Register generic netlink family to communicate changes to
+	 * userspace. */
+	err = genl_register_family_with_ops(&brc_genl_family,
+					    brc_genl_ops, ARRAY_SIZE(brc_genl_ops));
+	if (err)
+		goto error;
+
+	strcpy(brc_mc_group.name, "brcompat");
+	err = genl_register_mc_group(&brc_genl_family, &brc_mc_group);
+	if (err < 0)
+		goto err_unregister;
+
+	return 0;
+
+err_unregister:
+	genl_unregister_family(&brc_genl_family);
+error:
+	pr_emerg("failed to install!\n");
+	return err;
+}
+
+static void brc_cleanup(void)
+{
+	/* Unregister ioctl hooks */
+	ovs_dp_ioctl_hook = NULL;
+	brioctl_set(NULL);
+
+	genl_unregister_family(&brc_genl_family);
+}
+
+module_init(brc_init);
+module_exit(brc_cleanup);
+
+MODULE_DESCRIPTION("Open vSwitch bridge compatibility");
+MODULE_AUTHOR("Nicira Networks");
+MODULE_LICENSE("GPL");
-- 
1.7.1




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