net/8021q/vlan.c - kernel/msm-4.9 - Gitiles

 /*
  * INET		802.1Q VLAN
  *		Ethernet-type device handling.
  *
  * Authors:	Ben Greear <greearb@candelatech.com>
  *              Please send support related email to: netdev@vger.kernel.org
  *              VLAN Home Page: http://www.candelatech.com/~greear/vlan.html
  *
  * Fixes:
  *              Fix for packet capture - Nick Eggleston <nick@dccinc.com>;
  *		Add HW acceleration hooks - David S. Miller <davem@redhat.com>;
  *		Correct all the locking - David S. Miller <davem@redhat.com>;
  *		Use hash table for VLAN groups - David S. Miller <davem@redhat.com>
  *
  *		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.
  */

 #include <asm/uaccess.h> /* for copy_from_user */
 #include <linux/capability.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
 #include <net/datalink.h>
 #include <linux/mm.h>
 #include <linux/in.h>
 #include <linux/init.h>
 #include <net/p8022.h>
 #include <net/arp.h>
 #include <linux/rtnetlink.h>
 #include <linux/notifier.h>
 #include <net/net_namespace.h>

 #include <linux/if_vlan.h>
 #include "vlan.h"
 #include "vlanproc.h"

 #define DRV_VERSION "1.8"

 /* Global VLAN variables */

 /* Our listing of VLAN group(s) */
 static struct hlist_head vlan_group_hash[VLAN_GRP_HASH_SIZE];

 static char vlan_fullname[] = "802.1Q VLAN Support";
 static char vlan_version[] = DRV_VERSION;
 static char vlan_copyright[] = "Ben Greear <greearb@candelatech.com>";
 static char vlan_buggyright[] = "David S. Miller <davem@redhat.com>";

 /* Determines interface naming scheme. */
 unsigned short vlan_name_type = VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD;

 static struct packet_type vlan_packet_type = {
 	.type = __constant_htons(ETH_P_8021Q),
 	.func = vlan_skb_recv, /* VLAN receive method */
 };

 /* End of global variables definitions. */

 static inline unsigned int vlan_grp_hashfn(unsigned int idx)
 {
 	return ((idx >> VLAN_GRP_HASH_SHIFT) ^ idx) & VLAN_GRP_HASH_MASK;
 }

 /* Must be invoked with RCU read lock (no preempt) */
 static struct vlan_group *__vlan_find_group(int real_dev_ifindex)
 {
 	struct vlan_group *grp;
 	struct hlist_node *n;
 	int hash = vlan_grp_hashfn(real_dev_ifindex);

 	hlist_for_each_entry_rcu(grp, n, &vlan_group_hash[hash], hlist) {
 		if (grp->real_dev_ifindex == real_dev_ifindex)
 			return grp;
 	}

 	return NULL;
 }

 /*  Find the protocol handler.  Assumes VID < VLAN_VID_MASK.
  *
  * Must be invoked with RCU read lock (no preempt)
  */
 struct net_device *__find_vlan_dev(struct net_device *real_dev,
 				   unsigned short VID)
 {
 	struct vlan_group *grp = __vlan_find_group(real_dev->ifindex);

 	if (grp)
 		return vlan_group_get_device(grp, VID);

 	return NULL;
 }

 static void vlan_group_free(struct vlan_group *grp)
 {
 	int i;

 	for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++)
 		kfree(grp->vlan_devices_arrays[i]);
 	kfree(grp);
 }

 static struct vlan_group *vlan_group_alloc(int ifindex)
 {
 	struct vlan_group *grp;
 	unsigned int size;
 	unsigned int i;

 	grp = kzalloc(sizeof(struct vlan_group), GFP_KERNEL);
 	if (!grp)
 		return NULL;

 	size = sizeof(struct net_device *) * VLAN_GROUP_ARRAY_PART_LEN;

 	for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++) {
 		grp->vlan_devices_arrays[i] = kzalloc(size, GFP_KERNEL);
 		if (!grp->vlan_devices_arrays[i])
 			goto err;
 	}

 	grp->real_dev_ifindex = ifindex;
 	hlist_add_head_rcu(&grp->hlist,
 			   &vlan_group_hash[vlan_grp_hashfn(ifindex)]);
 	return grp;

 err:
 	vlan_group_free(grp);
 	return NULL;
 }

 static void vlan_rcu_free(struct rcu_head *rcu)
 {
 	vlan_group_free(container_of(rcu, struct vlan_group, rcu));
 }

 void unregister_vlan_dev(struct net_device *dev)
 {
 	struct vlan_dev_info *vlan = vlan_dev_info(dev);
 	struct net_device *real_dev = vlan->real_dev;
 	struct vlan_group *grp;
 	unsigned short vlan_id = vlan->vlan_id;

 	ASSERT_RTNL();

 	grp = __vlan_find_group(real_dev->ifindex);
 	BUG_ON(!grp);

 	vlan_proc_rem_dev(dev);

 	/* Take it out of our own structures, but be sure to interlock with
 	 * HW accelerating devices or SW vlan input packet processing.
 	 */
 	if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
 		real_dev->vlan_rx_kill_vid(real_dev, vlan_id);

 	vlan_group_set_device(grp, vlan_id, NULL);
 	grp->nr_vlans--;

 	synchronize_net();

 	/* If the group is now empty, kill off the group. */
 	if (grp->nr_vlans == 0) {
 		if (real_dev->features & NETIF_F_HW_VLAN_RX)
 			real_dev->vlan_rx_register(real_dev, NULL);

 		hlist_del_rcu(&grp->hlist);

 		/* Free the group, after all cpu's are done. */
 		call_rcu(&grp->rcu, vlan_rcu_free);
 	}

 	/* Get rid of the vlan's reference to real_dev */
 	dev_put(real_dev);

 	unregister_netdevice(dev);
 }

 static void vlan_transfer_operstate(const struct net_device *dev,
 				    struct net_device *vlandev)
 {
 	/* Have to respect userspace enforced dormant state
 	 * of real device, also must allow supplicant running
 	 * on VLAN device
 	 */
 	if (dev->operstate == IF_OPER_DORMANT)
 		netif_dormant_on(vlandev);
 	else
 		netif_dormant_off(vlandev);

 	if (netif_carrier_ok(dev)) {
 		if (!netif_carrier_ok(vlandev))
 			netif_carrier_on(vlandev);
 	} else {
 		if (netif_carrier_ok(vlandev))
 			netif_carrier_off(vlandev);
 	}
 }

 int vlan_check_real_dev(struct net_device *real_dev, unsigned short vlan_id)
 {
 	char *name = real_dev->name;

 	if (real_dev->features & NETIF_F_VLAN_CHALLENGED) {
 		pr_info("8021q: VLANs not supported on %s\n", name);
 		return -EOPNOTSUPP;
 	}

 	if ((real_dev->features & NETIF_F_HW_VLAN_RX) &&
 	    !real_dev->vlan_rx_register) {
 		pr_info("8021q: device %s has buggy VLAN hw accel\n", name);
 		return -EOPNOTSUPP;
 	}

 	if ((real_dev->features & NETIF_F_HW_VLAN_FILTER) &&
 	    (!real_dev->vlan_rx_add_vid || !real_dev->vlan_rx_kill_vid)) {
 		pr_info("8021q: Device %s has buggy VLAN hw accel\n", name);
 		return -EOPNOTSUPP;
 	}

 	/* The real device must be up and operating in order to
 	 * assosciate a VLAN device with it.
 	 */
 	if (!(real_dev->flags & IFF_UP))
 		return -ENETDOWN;

 	if (__find_vlan_dev(real_dev, vlan_id) != NULL)
 		return -EEXIST;

 	return 0;
 }

 int register_vlan_dev(struct net_device *dev)
 {
 	struct vlan_dev_info *vlan = vlan_dev_info(dev);
 	struct net_device *real_dev = vlan->real_dev;
 	unsigned short vlan_id = vlan->vlan_id;
 	struct vlan_group *grp, *ngrp = NULL;
 	int err;

 	grp = __vlan_find_group(real_dev->ifindex);
 	if (!grp) {
 		ngrp = grp = vlan_group_alloc(real_dev->ifindex);
 		if (!grp)
 			return -ENOBUFS;
 	}

 	err = register_netdevice(dev);
 	if (err < 0)
 		goto out_free_group;

 	/* Account for reference in struct vlan_dev_info */
 	dev_hold(real_dev);

 	vlan_transfer_operstate(real_dev, dev);
 	linkwatch_fire_event(dev); /* _MUST_ call rfc2863_policy() */

 	/* So, got the sucker initialized, now lets place
 	 * it into our local structure.
 	 */
 	vlan_group_set_device(grp, vlan_id, dev);
 	grp->nr_vlans++;

 	if (ngrp && real_dev->features & NETIF_F_HW_VLAN_RX)
 		real_dev->vlan_rx_register(real_dev, ngrp);
 	if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
 		real_dev->vlan_rx_add_vid(real_dev, vlan_id);

 	if (vlan_proc_add_dev(dev) < 0)
 		pr_warning("8021q: failed to add proc entry for %s\n",
 			   dev->name);
 	return 0;

 out_free_group:
 	if (ngrp)
 		vlan_group_free(ngrp);
 	return err;
 }

 /*  Attach a VLAN device to a mac address (ie Ethernet Card).
  *  Returns 0 if the device was created or a negative error code otherwise.
  */
 static int register_vlan_device(struct net_device *real_dev,
 				unsigned short VLAN_ID)
 {
 	struct net_device *new_dev;
 	char name[IFNAMSIZ];
 	int err;

 	if (VLAN_ID >= VLAN_VID_MASK)
 		return -ERANGE;

 	err = vlan_check_real_dev(real_dev, VLAN_ID);
 	if (err < 0)
 		return err;

 	/* Gotta set up the fields for the device. */
 	switch (vlan_name_type) {
 	case VLAN_NAME_TYPE_RAW_PLUS_VID:
 		/* name will look like:	 eth1.0005 */
 		snprintf(name, IFNAMSIZ, "%s.%.4i", real_dev->name, VLAN_ID);
 		break;
 	case VLAN_NAME_TYPE_PLUS_VID_NO_PAD:
 		/* Put our vlan.VID in the name.
 		 * Name will look like:	 vlan5
 		 */
 		snprintf(name, IFNAMSIZ, "vlan%i", VLAN_ID);
 		break;
 	case VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD:
 		/* Put our vlan.VID in the name.
 		 * Name will look like:	 eth0.5
 		 */
 		snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, VLAN_ID);
 		break;
 	case VLAN_NAME_TYPE_PLUS_VID:
 		/* Put our vlan.VID in the name.
 		 * Name will look like:	 vlan0005
 		 */
 	default:
 		snprintf(name, IFNAMSIZ, "vlan%.4i", VLAN_ID);
 	}

 	new_dev = alloc_netdev(sizeof(struct vlan_dev_info), name,
 			       vlan_setup);

 	if (new_dev == NULL)
 		return -ENOBUFS;

 	/* need 4 bytes for extra VLAN header info,
 	 * hope the underlying device can handle it.
 	 */
 	new_dev->mtu = real_dev->mtu;

 	vlan_dev_info(new_dev)->vlan_id = VLAN_ID; /* 1 through VLAN_VID_MASK */
 	vlan_dev_info(new_dev)->real_dev = real_dev;
 	vlan_dev_info(new_dev)->dent = NULL;
 	vlan_dev_info(new_dev)->flags = VLAN_FLAG_REORDER_HDR;

 	new_dev->rtnl_link_ops = &vlan_link_ops;
 	err = register_vlan_dev(new_dev);
 	if (err < 0)
 		goto out_free_newdev;

 	return 0;

 out_free_newdev:
 	free_netdev(new_dev);
 	return err;
 }

 static void vlan_sync_address(struct net_device *dev,
 			      struct net_device *vlandev)
 {
 	struct vlan_dev_info *vlan = vlan_dev_info(vlandev);

 	/* May be called without an actual change */
 	if (!compare_ether_addr(vlan->real_dev_addr, dev->dev_addr))
 		return;

 	/* vlan address was different from the old address and is equal to
 	 * the new address */
 	if (compare_ether_addr(vlandev->dev_addr, vlan->real_dev_addr) &&
 	    !compare_ether_addr(vlandev->dev_addr, dev->dev_addr))
 		dev_unicast_delete(dev, vlandev->dev_addr, ETH_ALEN);

 	/* vlan address was equal to the old address and is different from
 	 * the new address */
 	if (!compare_ether_addr(vlandev->dev_addr, vlan->real_dev_addr) &&
 	    compare_ether_addr(vlandev->dev_addr, dev->dev_addr))
 		dev_unicast_add(dev, vlandev->dev_addr, ETH_ALEN);

 	memcpy(vlan->real_dev_addr, dev->dev_addr, ETH_ALEN);
 }

 static void __vlan_device_event(struct net_device *dev, unsigned long event)
 {
 	switch (event) {
 	case NETDEV_CHANGENAME:
 		vlan_proc_rem_dev(dev);
 		if (vlan_proc_add_dev(dev) < 0)
 			pr_warning("8021q: failed to change proc name for %s\n",
 					dev->name);
 		break;
 	}
 }

 static int vlan_device_event(struct notifier_block *unused, unsigned long event,
 			     void *ptr)
 {
 	struct net_device *dev = ptr;
 	struct vlan_group *grp;
 	int i, flgs;
 	struct net_device *vlandev;

 	if (dev->nd_net != &init_net)
 		return NOTIFY_DONE;

 	if (is_vlan_dev(dev)) {
 		__vlan_device_event(dev, event);
 		goto out;
 	}

 	grp = __vlan_find_group(dev->ifindex);
 	if (!grp)
 		goto out;

 	/* It is OK that we do not hold the group lock right now,
 	 * as we run under the RTNL lock.
 	 */

 	switch (event) {
 	case NETDEV_CHANGE:
 		/* Propagate real device state to vlan devices */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
 			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;

 			vlan_transfer_operstate(dev, vlandev);
 		}
 		break;

 	case NETDEV_CHANGEADDR:
 		/* Adjust unicast filters on underlying device */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
 			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;

 			flgs = vlandev->flags;
 			if (!(flgs & IFF_UP))
 				continue;

 			vlan_sync_address(dev, vlandev);
 		}
 		break;

 	case NETDEV_DOWN:
 		/* Put all VLANs for this dev in the down state too.  */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
 			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;

 			flgs = vlandev->flags;
 			if (!(flgs & IFF_UP))
 				continue;

 			dev_change_flags(vlandev, flgs & ~IFF_UP);
 		}
 		break;

 	case NETDEV_UP:
 		/* Put all VLANs for this dev in the up state too.  */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
 			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;

 			flgs = vlandev->flags;
 			if (flgs & IFF_UP)
 				continue;

 			dev_change_flags(vlandev, flgs | IFF_UP);
 		}
 		break;

 	case NETDEV_UNREGISTER:
 		/* Delete all VLANs for this dev. */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
 			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;

 			/* unregistration of last vlan destroys group, abort
 			 * afterwards */
 			if (grp->nr_vlans == 1)
 				i = VLAN_GROUP_ARRAY_LEN;

 			unregister_vlan_dev(vlandev);
 		}
 		break;
 	}

 out:
 	return NOTIFY_DONE;
 }

 static struct notifier_block vlan_notifier_block __read_mostly = {
 	.notifier_call = vlan_device_event,
 };

 /*
  *	VLAN IOCTL handler.
  *	o execute requested action or pass command to the device driver
  *   arg is really a struct vlan_ioctl_args __user *.
  */
 static int vlan_ioctl_handler(struct net *net, void __user *arg)
 {
 	int err;
 	unsigned short vid = 0;
 	struct vlan_ioctl_args args;
 	struct net_device *dev = NULL;

 	if (copy_from_user(&args, arg, sizeof(struct vlan_ioctl_args)))
 		return -EFAULT;

 	/* Null terminate this sucker, just in case. */
 	args.device1[23] = 0;
 	args.u.device2[23] = 0;

 	rtnl_lock();

 	switch (args.cmd) {
 	case SET_VLAN_INGRESS_PRIORITY_CMD:
 	case SET_VLAN_EGRESS_PRIORITY_CMD:
 	case SET_VLAN_FLAG_CMD:
 	case ADD_VLAN_CMD:
 	case DEL_VLAN_CMD:
 	case GET_VLAN_REALDEV_NAME_CMD:
 	case GET_VLAN_VID_CMD:
 		err = -ENODEV;
 		dev = __dev_get_by_name(&init_net, args.device1);
 		if (!dev)
 			goto out;

 		err = -EINVAL;
 		if (args.cmd != ADD_VLAN_CMD &&
 		    !(dev->priv_flags & IFF_802_1Q_VLAN))
 			goto out;
 	}

 	switch (args.cmd) {
 	case SET_VLAN_INGRESS_PRIORITY_CMD:
 		err = -EPERM;
 		if (!capable(CAP_NET_ADMIN))
 			break;
 		vlan_dev_set_ingress_priority(dev,
 					      args.u.skb_priority,
 					      args.vlan_qos);
 		err = 0;
 		break;

 	case SET_VLAN_EGRESS_PRIORITY_CMD:
 		err = -EPERM;
 		if (!capable(CAP_NET_ADMIN))
 			break;
 		err = vlan_dev_set_egress_priority(dev,
 						   args.u.skb_priority,
 						   args.vlan_qos);
 		break;

 	case SET_VLAN_FLAG_CMD:
 		err = -EPERM;
 		if (!capable(CAP_NET_ADMIN))
 			break;
 		err = vlan_dev_set_vlan_flag(dev,
 					     args.u.flag,
 					     args.vlan_qos);
 		break;

 	case SET_VLAN_NAME_TYPE_CMD:
 		err = -EPERM;
 		if (!capable(CAP_NET_ADMIN))
 			break;
 		if ((args.u.name_type >= 0) &&
 		    (args.u.name_type < VLAN_NAME_TYPE_HIGHEST)) {
 			vlan_name_type = args.u.name_type;
 			err = 0;
 		} else {
 			err = -EINVAL;
 		}
 		break;

 	case ADD_VLAN_CMD:
 		err = -EPERM;
 		if (!capable(CAP_NET_ADMIN))
 			break;
 		err = register_vlan_device(dev, args.u.VID);
 		break;

 	case DEL_VLAN_CMD:
 		err = -EPERM;
 		if (!capable(CAP_NET_ADMIN))
 			break;
 		unregister_vlan_dev(dev);
 		err = 0;
 		break;

 	case GET_VLAN_REALDEV_NAME_CMD:
 		err = 0;
 		vlan_dev_get_realdev_name(dev, args.u.device2);
 		if (copy_to_user(arg, &args,
 				 sizeof(struct vlan_ioctl_args)))
 			err = -EFAULT;
 		break;

 	case GET_VLAN_VID_CMD:
 		err = 0;
 		vlan_dev_get_vid(dev, &vid);
 		args.u.VID = vid;
 		if (copy_to_user(arg, &args,
 				 sizeof(struct vlan_ioctl_args)))
 		      err = -EFAULT;
 		break;

 	default:
 		err = -EOPNOTSUPP;
 		break;
 	}
 out:
 	rtnl_unlock();
 	return err;
 }

 static int __init vlan_proto_init(void)
 {
 	int err;

 	pr_info("%s v%s %s\n", vlan_fullname, vlan_version, vlan_copyright);
 	pr_info("All bugs added by %s\n", vlan_buggyright);

 	err = vlan_proc_init();
 	if (err < 0)
 		goto err1;

 	err = register_netdevice_notifier(&vlan_notifier_block);
 	if (err < 0)
 		goto err2;

 	err = vlan_netlink_init();
 	if (err < 0)
 		goto err3;

 	dev_add_pack(&vlan_packet_type);
 	vlan_ioctl_set(vlan_ioctl_handler);
 	return 0;

 err3:
 	unregister_netdevice_notifier(&vlan_notifier_block);
 err2:
 	vlan_proc_cleanup();
 err1:
 	return err;
 }

 static void __exit vlan_cleanup_module(void)
 {
 	unsigned int i;

 	vlan_ioctl_set(NULL);
 	vlan_netlink_fini();

 	unregister_netdevice_notifier(&vlan_notifier_block);

 	dev_remove_pack(&vlan_packet_type);

 	/* This table must be empty if there are no module references left. */
 	for (i = 0; i < VLAN_GRP_HASH_SIZE; i++)
 		BUG_ON(!hlist_empty(&vlan_group_hash[i]));

 	vlan_proc_cleanup();

 	synchronize_net();
 }

 module_init(vlan_proto_init);
 module_exit(vlan_cleanup_module);

 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_VERSION);
	/*
	* INET 802.1Q VLAN
	* Ethernet-type device handling.
	*
	* Authors: Ben Greear <greearb@candelatech.com>
	* Please send support related email to: netdev@vger.kernel.org
	* VLAN Home Page: http://www.candelatech.com/~greear/vlan.html
	*
	* Fixes:
	* Fix for packet capture - Nick Eggleston <nick@dccinc.com>;
	* Add HW acceleration hooks - David S. Miller <davem@redhat.com>;
	* Correct all the locking - David S. Miller <davem@redhat.com>;
	* Use hash table for VLAN groups - David S. Miller <davem@redhat.com>
	*
	* 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.
	*/

	#include <asm/uaccess.h> /* for copy_from_user */
	#include <linux/capability.h>
	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/skbuff.h>
	#include <net/datalink.h>
	#include <linux/mm.h>
	#include <linux/in.h>
	#include <linux/init.h>
	#include <net/p8022.h>
	#include <net/arp.h>
	#include <linux/rtnetlink.h>
	#include <linux/notifier.h>
	#include <net/net_namespace.h>

	#include <linux/if_vlan.h>
	#include "vlan.h"
	#include "vlanproc.h"

	#define DRV_VERSION "1.8"

	/* Global VLAN variables */

	/* Our listing of VLAN group(s) */
	static struct hlist_head vlan_group_hash[VLAN_GRP_HASH_SIZE];

	static char vlan_fullname[] = "802.1Q VLAN Support";
	static char vlan_version[] = DRV_VERSION;
	static char vlan_copyright[] = "Ben Greear <greearb@candelatech.com>";
	static char vlan_buggyright[] = "David S. Miller <davem@redhat.com>";

	/* Determines interface naming scheme. */
	unsigned short vlan_name_type = VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD;

	static struct packet_type vlan_packet_type = {
	.type = __constant_htons(ETH_P_8021Q),
	.func = vlan_skb_recv, /* VLAN receive method */
	};

	/* End of global variables definitions. */

	static inline unsigned int vlan_grp_hashfn(unsigned int idx)
	{
	return ((idx >> VLAN_GRP_HASH_SHIFT) ^ idx) & VLAN_GRP_HASH_MASK;
	}

	/* Must be invoked with RCU read lock (no preempt) */
	static struct vlan_group *__vlan_find_group(int real_dev_ifindex)
	{
	struct vlan_group *grp;
	struct hlist_node *n;
	int hash = vlan_grp_hashfn(real_dev_ifindex);

	hlist_for_each_entry_rcu(grp, n, &vlan_group_hash[hash], hlist) {
	if (grp->real_dev_ifindex == real_dev_ifindex)
	return grp;
	}

	return NULL;
	}

	/* Find the protocol handler. Assumes VID < VLAN_VID_MASK.
	*
	* Must be invoked with RCU read lock (no preempt)
	*/
	struct net_device __find_vlan_dev(struct net_device real_dev,
	unsigned short VID)
	{
	struct vlan_group *grp = __vlan_find_group(real_dev->ifindex);

	if (grp)
	return vlan_group_get_device(grp, VID);

	return NULL;
	}

	static void vlan_group_free(struct vlan_group *grp)
	{
	int i;

	for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++)
	kfree(grp->vlan_devices_arrays[i]);
	kfree(grp);
	}

	static struct vlan_group *vlan_group_alloc(int ifindex)
	{
	struct vlan_group *grp;
	unsigned int size;
	unsigned int i;

	grp = kzalloc(sizeof(struct vlan_group), GFP_KERNEL);
	if (!grp)
	return NULL;

	size = sizeof(struct net_device ) VLAN_GROUP_ARRAY_PART_LEN;

	for (i = 0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++) {
	grp->vlan_devices_arrays[i] = kzalloc(size, GFP_KERNEL);
	if (!grp->vlan_devices_arrays[i])
	goto err;
	}

	grp->real_dev_ifindex = ifindex;
	hlist_add_head_rcu(&grp->hlist,
	&vlan_group_hash[vlan_grp_hashfn(ifindex)]);
	return grp;

	err:
	vlan_group_free(grp);
	return NULL;
	}

	static void vlan_rcu_free(struct rcu_head *rcu)
	{
	vlan_group_free(container_of(rcu, struct vlan_group, rcu));
	}

	void unregister_vlan_dev(struct net_device *dev)
	{
	struct vlan_dev_info *vlan = vlan_dev_info(dev);
	struct net_device *real_dev = vlan->real_dev;
	struct vlan_group *grp;
	unsigned short vlan_id = vlan->vlan_id;

	ASSERT_RTNL();

	grp = __vlan_find_group(real_dev->ifindex);
	BUG_ON(!grp);

	vlan_proc_rem_dev(dev);

	/* Take it out of our own structures, but be sure to interlock with
	* HW accelerating devices or SW vlan input packet processing.
	*/
	if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
	real_dev->vlan_rx_kill_vid(real_dev, vlan_id);

	vlan_group_set_device(grp, vlan_id, NULL);
	grp->nr_vlans--;

	synchronize_net();

	/* If the group is now empty, kill off the group. */
	if (grp->nr_vlans == 0) {
	if (real_dev->features & NETIF_F_HW_VLAN_RX)
	real_dev->vlan_rx_register(real_dev, NULL);

	hlist_del_rcu(&grp->hlist);

	/* Free the group, after all cpu's are done. */
	call_rcu(&grp->rcu, vlan_rcu_free);
	}

	/* Get rid of the vlan's reference to real_dev */
	dev_put(real_dev);

	unregister_netdevice(dev);
	}

	static void vlan_transfer_operstate(const struct net_device *dev,
	struct net_device *vlandev)
	{
	/* Have to respect userspace enforced dormant state
	* of real device, also must allow supplicant running
	* on VLAN device
	*/
	if (dev->operstate == IF_OPER_DORMANT)
	netif_dormant_on(vlandev);
	else
	netif_dormant_off(vlandev);

	if (netif_carrier_ok(dev)) {
	if (!netif_carrier_ok(vlandev))
	netif_carrier_on(vlandev);
	} else {
	if (netif_carrier_ok(vlandev))
	netif_carrier_off(vlandev);
	}
	}

	int vlan_check_real_dev(struct net_device *real_dev, unsigned short vlan_id)
	{
	char *name = real_dev->name;

	if (real_dev->features & NETIF_F_VLAN_CHALLENGED) {
	pr_info("8021q: VLANs not supported on %s\n", name);
	return -EOPNOTSUPP;
	}

	if ((real_dev->features & NETIF_F_HW_VLAN_RX) &&
	!real_dev->vlan_rx_register) {
	pr_info("8021q: device %s has buggy VLAN hw accel\n", name);
	return -EOPNOTSUPP;
	}

	if ((real_dev->features & NETIF_F_HW_VLAN_FILTER) &&
	(!real_dev->vlan_rx_add_vid \|\| !real_dev->vlan_rx_kill_vid)) {
	pr_info("8021q: Device %s has buggy VLAN hw accel\n", name);
	return -EOPNOTSUPP;
	}

	/* The real device must be up and operating in order to
	* assosciate a VLAN device with it.
	*/
	if (!(real_dev->flags & IFF_UP))
	return -ENETDOWN;

	if (__find_vlan_dev(real_dev, vlan_id) != NULL)
	return -EEXIST;

	return 0;
	}

	int register_vlan_dev(struct net_device *dev)
	{
	struct vlan_dev_info *vlan = vlan_dev_info(dev);
	struct net_device *real_dev = vlan->real_dev;
	unsigned short vlan_id = vlan->vlan_id;
	struct vlan_group grp, ngrp = NULL;
	int err;

	grp = __vlan_find_group(real_dev->ifindex);
	if (!grp) {
	ngrp = grp = vlan_group_alloc(real_dev->ifindex);
	if (!grp)
	return -ENOBUFS;
	}

	err = register_netdevice(dev);
	if (err < 0)
	goto out_free_group;

	/* Account for reference in struct vlan_dev_info */
	dev_hold(real_dev);

	vlan_transfer_operstate(real_dev, dev);
	linkwatch_fire_event(dev); /* _MUST_ call rfc2863_policy() */

	/* So, got the sucker initialized, now lets place
	* it into our local structure.
	*/
	vlan_group_set_device(grp, vlan_id, dev);
	grp->nr_vlans++;

	if (ngrp && real_dev->features & NETIF_F_HW_VLAN_RX)
	real_dev->vlan_rx_register(real_dev, ngrp);
	if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
	real_dev->vlan_rx_add_vid(real_dev, vlan_id);

	if (vlan_proc_add_dev(dev) < 0)
	pr_warning("8021q: failed to add proc entry for %s\n",
	dev->name);
	return 0;

	out_free_group:
	if (ngrp)
	vlan_group_free(ngrp);
	return err;
	}

	/* Attach a VLAN device to a mac address (ie Ethernet Card).
	* Returns 0 if the device was created or a negative error code otherwise.
	*/
	static int register_vlan_device(struct net_device *real_dev,
	unsigned short VLAN_ID)
	{
	struct net_device *new_dev;
	char name[IFNAMSIZ];
	int err;

	if (VLAN_ID >= VLAN_VID_MASK)
	return -ERANGE;

	err = vlan_check_real_dev(real_dev, VLAN_ID);
	if (err < 0)
	return err;

	/* Gotta set up the fields for the device. */
	switch (vlan_name_type) {
	case VLAN_NAME_TYPE_RAW_PLUS_VID:
	/* name will look like: eth1.0005 */
	snprintf(name, IFNAMSIZ, "%s.%.4i", real_dev->name, VLAN_ID);
	break;
	case VLAN_NAME_TYPE_PLUS_VID_NO_PAD:
	/* Put our vlan.VID in the name.
	* Name will look like: vlan5
	*/
	snprintf(name, IFNAMSIZ, "vlan%i", VLAN_ID);
	break;
	case VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD:
	/* Put our vlan.VID in the name.
	* Name will look like: eth0.5
	*/
	snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, VLAN_ID);
	break;
	case VLAN_NAME_TYPE_PLUS_VID:
	/* Put our vlan.VID in the name.
	* Name will look like: vlan0005
	*/
	default:
	snprintf(name, IFNAMSIZ, "vlan%.4i", VLAN_ID);
	}

	new_dev = alloc_netdev(sizeof(struct vlan_dev_info), name,
	vlan_setup);

	if (new_dev == NULL)
	return -ENOBUFS;

	/* need 4 bytes for extra VLAN header info,
	* hope the underlying device can handle it.
	*/
	new_dev->mtu = real_dev->mtu;

	vlan_dev_info(new_dev)->vlan_id = VLAN_ID; /* 1 through VLAN_VID_MASK */
	vlan_dev_info(new_dev)->real_dev = real_dev;
	vlan_dev_info(new_dev)->dent = NULL;
	vlan_dev_info(new_dev)->flags = VLAN_FLAG_REORDER_HDR;

	new_dev->rtnl_link_ops = &vlan_link_ops;
	err = register_vlan_dev(new_dev);
	if (err < 0)
	goto out_free_newdev;

	return 0;

	out_free_newdev:
	free_netdev(new_dev);
	return err;
	}

	static void vlan_sync_address(struct net_device *dev,
	struct net_device *vlandev)
	{
	struct vlan_dev_info *vlan = vlan_dev_info(vlandev);

	/* May be called without an actual change */
	if (!compare_ether_addr(vlan->real_dev_addr, dev->dev_addr))
	return;

	/* vlan address was different from the old address and is equal to
	* the new address */
	if (compare_ether_addr(vlandev->dev_addr, vlan->real_dev_addr) &&
	!compare_ether_addr(vlandev->dev_addr, dev->dev_addr))
	dev_unicast_delete(dev, vlandev->dev_addr, ETH_ALEN);

	/* vlan address was equal to the old address and is different from
	* the new address */
	if (!compare_ether_addr(vlandev->dev_addr, vlan->real_dev_addr) &&
	compare_ether_addr(vlandev->dev_addr, dev->dev_addr))
	dev_unicast_add(dev, vlandev->dev_addr, ETH_ALEN);

	memcpy(vlan->real_dev_addr, dev->dev_addr, ETH_ALEN);
	}

	static void __vlan_device_event(struct net_device *dev, unsigned long event)
	{
	switch (event) {
	case NETDEV_CHANGENAME:
	vlan_proc_rem_dev(dev);
	if (vlan_proc_add_dev(dev) < 0)
	pr_warning("8021q: failed to change proc name for %s\n",
	dev->name);
	break;
	}
	}

	static int vlan_device_event(struct notifier_block *unused, unsigned long event,
	void *ptr)
	{
	struct net_device *dev = ptr;
	struct vlan_group *grp;
	int i, flgs;
	struct net_device *vlandev;

	if (dev->nd_net != &init_net)
	return NOTIFY_DONE;

	if (is_vlan_dev(dev)) {
	__vlan_device_event(dev, event);
	goto out;
	}

	grp = __vlan_find_group(dev->ifindex);
	if (!grp)
	goto out;

	/* It is OK that we do not hold the group lock right now,
	* as we run under the RTNL lock.
	*/

	switch (event) {
	case NETDEV_CHANGE:
	/* Propagate real device state to vlan devices */
	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
	vlandev = vlan_group_get_device(grp, i);
	if (!vlandev)
	continue;

	vlan_transfer_operstate(dev, vlandev);
	}
	break;

	case NETDEV_CHANGEADDR:
	/* Adjust unicast filters on underlying device */
	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
	vlandev = vlan_group_get_device(grp, i);
	if (!vlandev)
	continue;

	flgs = vlandev->flags;
	if (!(flgs & IFF_UP))
	continue;

	vlan_sync_address(dev, vlandev);
	}
	break;

	case NETDEV_DOWN:
	/* Put all VLANs for this dev in the down state too. */
	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
	vlandev = vlan_group_get_device(grp, i);
	if (!vlandev)
	continue;

	flgs = vlandev->flags;
	if (!(flgs & IFF_UP))
	continue;

	dev_change_flags(vlandev, flgs & ~IFF_UP);
	}
	break;

	case NETDEV_UP:
	/* Put all VLANs for this dev in the up state too. */
	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
	vlandev = vlan_group_get_device(grp, i);
	if (!vlandev)
	continue;

	flgs = vlandev->flags;
	if (flgs & IFF_UP)
	continue;

	dev_change_flags(vlandev, flgs \| IFF_UP);
	}
	break;

	case NETDEV_UNREGISTER:
	/* Delete all VLANs for this dev. */
	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
	vlandev = vlan_group_get_device(grp, i);
	if (!vlandev)
	continue;

	/* unregistration of last vlan destroys group, abort
	* afterwards */
	if (grp->nr_vlans == 1)
	i = VLAN_GROUP_ARRAY_LEN;

	unregister_vlan_dev(vlandev);
	}
	break;
	}

	out:
	return NOTIFY_DONE;
	}

	static struct notifier_block vlan_notifier_block __read_mostly = {
	.notifier_call = vlan_device_event,
	};

	/*
	* VLAN IOCTL handler.
	* o execute requested action or pass command to the device driver
	* arg is really a struct vlan_ioctl_args __user *.
	*/
	static int vlan_ioctl_handler(struct net net, void __user arg)
	{
	int err;
	unsigned short vid = 0;
	struct vlan_ioctl_args args;
	struct net_device *dev = NULL;

	if (copy_from_user(&args, arg, sizeof(struct vlan_ioctl_args)))
	return -EFAULT;

	/* Null terminate this sucker, just in case. */
	args.device1[23] = 0;
	args.u.device2[23] = 0;

	rtnl_lock();

	switch (args.cmd) {
	case SET_VLAN_INGRESS_PRIORITY_CMD:
	case SET_VLAN_EGRESS_PRIORITY_CMD:
	case SET_VLAN_FLAG_CMD:
	case ADD_VLAN_CMD:
	case DEL_VLAN_CMD:
	case GET_VLAN_REALDEV_NAME_CMD:
	case GET_VLAN_VID_CMD:
	err = -ENODEV;
	dev = __dev_get_by_name(&init_net, args.device1);
	if (!dev)
	goto out;

	err = -EINVAL;
	if (args.cmd != ADD_VLAN_CMD &&
	!(dev->priv_flags & IFF_802_1Q_VLAN))
	goto out;
	}

	switch (args.cmd) {
	case SET_VLAN_INGRESS_PRIORITY_CMD:
	err = -EPERM;
	if (!capable(CAP_NET_ADMIN))
	break;
	vlan_dev_set_ingress_priority(dev,
	args.u.skb_priority,
	args.vlan_qos);
	err = 0;
	break;

	case SET_VLAN_EGRESS_PRIORITY_CMD:
	err = -EPERM;
	if (!capable(CAP_NET_ADMIN))
	break;
	err = vlan_dev_set_egress_priority(dev,
	args.u.skb_priority,
	args.vlan_qos);
	break;

	case SET_VLAN_FLAG_CMD:
	err = -EPERM;
	if (!capable(CAP_NET_ADMIN))
	break;
	err = vlan_dev_set_vlan_flag(dev,
	args.u.flag,
	args.vlan_qos);
	break;

	case SET_VLAN_NAME_TYPE_CMD:
	err = -EPERM;
	if (!capable(CAP_NET_ADMIN))
	break;
	if ((args.u.name_type >= 0) &&
	(args.u.name_type < VLAN_NAME_TYPE_HIGHEST)) {
	vlan_name_type = args.u.name_type;
	err = 0;
	} else {
	err = -EINVAL;
	}
	break;

	case ADD_VLAN_CMD:
	err = -EPERM;
	if (!capable(CAP_NET_ADMIN))
	break;
	err = register_vlan_device(dev, args.u.VID);
	break;

	case DEL_VLAN_CMD:
	err = -EPERM;
	if (!capable(CAP_NET_ADMIN))
	break;
	unregister_vlan_dev(dev);
	err = 0;
	break;

	case GET_VLAN_REALDEV_NAME_CMD:
	err = 0;
	vlan_dev_get_realdev_name(dev, args.u.device2);
	if (copy_to_user(arg, &args,
	sizeof(struct vlan_ioctl_args)))
	err = -EFAULT;
	break;

	case GET_VLAN_VID_CMD:
	err = 0;
	vlan_dev_get_vid(dev, &vid);
	args.u.VID = vid;
	if (copy_to_user(arg, &args,
	sizeof(struct vlan_ioctl_args)))
	err = -EFAULT;
	break;

	default:
	err = -EOPNOTSUPP;
	break;
	}
	out:
	rtnl_unlock();
	return err;
	}

	static int __init vlan_proto_init(void)
	{
	int err;

	pr_info("%s v%s %s\n", vlan_fullname, vlan_version, vlan_copyright);
	pr_info("All bugs added by %s\n", vlan_buggyright);

	err = vlan_proc_init();
	if (err < 0)
	goto err1;

	err = register_netdevice_notifier(&vlan_notifier_block);
	if (err < 0)
	goto err2;

	err = vlan_netlink_init();
	if (err < 0)
	goto err3;

	dev_add_pack(&vlan_packet_type);
	vlan_ioctl_set(vlan_ioctl_handler);
	return 0;

	err3:
	unregister_netdevice_notifier(&vlan_notifier_block);
	err2:
	vlan_proc_cleanup();
	err1:
	return err;
	}

	static void __exit vlan_cleanup_module(void)
	{
	unsigned int i;

	vlan_ioctl_set(NULL);
	vlan_netlink_fini();

	unregister_netdevice_notifier(&vlan_notifier_block);

	dev_remove_pack(&vlan_packet_type);

	/* This table must be empty if there are no module references left. */
	for (i = 0; i < VLAN_GRP_HASH_SIZE; i++)
	BUG_ON(!hlist_empty(&vlan_group_hash[i]));

	vlan_proc_cleanup();

	synchronize_net();
	}

	module_init(vlan_proto_init);
	module_exit(vlan_cleanup_module);

	MODULE_LICENSE("GPL");
	MODULE_VERSION(DRV_VERSION);