/*
   *	IP multicast routing support for mrouted 3.6/3.8
   *

   *		(c) 1995 Alan Cox, <alan@lxorguk.ukuu.org.uk>

   *	  Linux Consultancy and Custom Driver Development
   *
   *	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.
   *

   *	Fixes:
   *	Michael Chastain	:	Incorrect size of copying.
   *	Alan Cox		:	Added the cache manager code
   *	Alan Cox		:	Fixed the clone/copy bug and device race.
   *	Mike McLagan		:	Routing by source
   *	Malcolm Beattie		:	Buffer handling fixes.
   *	Alexey Kuznetsov	:	Double buffer free and other fixes.
   *	SVR Anand		:	Fixed several multicast bugs and problems.
   *	Alexey Kuznetsov	:	Status, optimisations and more.
   *	Brad Parker		:	Better behaviour on mrouted upcall
   *					overflow.
   *      Carlos Picoto           :       PIMv1 Support
   *	Pavlin Ivanov Radoslavov:	PIMv2 Registers must checksum only PIM header

   *					Relax this requirement to work with older peers.

   *
   */

  #include <asm/system.h>
  #include <asm/uaccess.h>
  #include <linux/types.h>

  #include <linux/capability.h>

  #include <linux/errno.h>
  #include <linux/timer.h>
  #include <linux/mm.h>
  #include <linux/kernel.h>
  #include <linux/fcntl.h>
  #include <linux/stat.h>
  #include <linux/socket.h>
  #include <linux/in.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/inetdevice.h>
  #include <linux/igmp.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/mroute.h>
  #include <linux/init.h>

  #include <linux/if_ether.h>

  #include <linux/slab.h>

  #include <net/net_namespace.h>

  #include <net/ip.h>
  #include <net/protocol.h>
  #include <linux/skbuff.h>

  #include <net/route.h>

  #include <net/sock.h>
  #include <net/icmp.h>
  #include <net/udp.h>
  #include <net/raw.h>
  #include <linux/notifier.h>
  #include <linux/if_arp.h>
  #include <linux/netfilter_ipv4.h>

  #include <linux/compat.h>

  #include <linux/export.h>

  #include <net/ipip.h>
  #include <net/checksum.h>

  #include <net/netlink.h>

  #include <net/fib_rules.h>

  
  #if defined(CONFIG_IP_PIMSM_V1) || defined(CONFIG_IP_PIMSM_V2)
  #define CONFIG_IP_PIMSM	1
  #endif

  struct mr_table {

  	struct list_head	list;

  #ifdef CONFIG_NET_NS
  	struct net		*net;
  #endif

  	u32			id;

  	struct sock __rcu	*mroute_sk;

  	struct timer_list	ipmr_expire_timer;
  	struct list_head	mfc_unres_queue;
  	struct list_head	mfc_cache_array[MFC_LINES];
  	struct vif_device	vif_table[MAXVIFS];
  	int			maxvif;
  	atomic_t		cache_resolve_queue_len;
  	int			mroute_do_assert;
  	int			mroute_do_pim;
  #if defined(CONFIG_IP_PIMSM_V1) || defined(CONFIG_IP_PIMSM_V2)
  	int			mroute_reg_vif_num;
  #endif
  };

  struct ipmr_rule {
  	struct fib_rule		common;
  };
  
  struct ipmr_result {
  	struct mr_table		*mrt;
  };

  /* Big lock, protecting vif table, mrt cache and mroute socket state.

   * Note that the changes are semaphored via rtnl_lock.

   */
  
  static DEFINE_RWLOCK(mrt_lock);
  
  /*
   *	Multicast router control variables
   */

  #define VIF_EXISTS(_mrt, _idx) ((_mrt)->vif_table[_idx].dev != NULL)

  
  /* Special spinlock for queue of unresolved entries */
  static DEFINE_SPINLOCK(mfc_unres_lock);
  
  /* We return to original Alan's scheme. Hash table of resolved

   * entries is changed only in process context and protected
   * with weak lock mrt_lock. Queue of unresolved entries is protected
   * with strong spinlock mfc_unres_lock.
   *
   * In this case data path is free of exclusive locks at all.

   */

  static struct kmem_cache *mrt_cachep __read_mostly;

  static struct mr_table *ipmr_new_table(struct net *net, u32 id);

  static int ip_mr_forward(struct net *net, struct mr_table *mrt,
  			 struct sk_buff *skb, struct mfc_cache *cache,
  			 int local);
  static int ipmr_cache_report(struct mr_table *mrt,

  			     struct sk_buff *pkt, vifi_t vifi, int assert);

  static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
  			      struct mfc_cache *c, struct rtmsg *rtm);

  static void ipmr_expire_process(unsigned long arg);
  
  #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
  #define ipmr_for_each_table(mrt, net) \
  	list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list)
  
  static struct mr_table *ipmr_get_table(struct net *net, u32 id)
  {
  	struct mr_table *mrt;
  
  	ipmr_for_each_table(mrt, net) {
  		if (mrt->id == id)
  			return mrt;
  	}
  	return NULL;
  }

  static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,

  			   struct mr_table **mrt)
  {
  	struct ipmr_result res;
  	struct fib_lookup_arg arg = { .result = &res, };
  	int err;

  	err = fib_rules_lookup(net->ipv4.mr_rules_ops,
  			       flowi4_to_flowi(flp4), 0, &arg);

  	if (err < 0)
  		return err;
  	*mrt = res.mrt;
  	return 0;
  }
  
  static int ipmr_rule_action(struct fib_rule *rule, struct flowi *flp,
  			    int flags, struct fib_lookup_arg *arg)
  {
  	struct ipmr_result *res = arg->result;
  	struct mr_table *mrt;

  	switch (rule->action) {
  	case FR_ACT_TO_TBL:
  		break;
  	case FR_ACT_UNREACHABLE:
  		return -ENETUNREACH;
  	case FR_ACT_PROHIBIT:
  		return -EACCES;
  	case FR_ACT_BLACKHOLE:
  	default:
  		return -EINVAL;
  	}
  
  	mrt = ipmr_get_table(rule->fr_net, rule->table);
  	if (mrt == NULL)
  		return -EAGAIN;
  	res->mrt = mrt;
  	return 0;
  }
  
  static int ipmr_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
  {
  	return 1;
  }
  
  static const struct nla_policy ipmr_rule_policy[FRA_MAX + 1] = {
  	FRA_GENERIC_POLICY,
  };
  
  static int ipmr_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
  			       struct fib_rule_hdr *frh, struct nlattr **tb)
  {
  	return 0;
  }
  
  static int ipmr_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
  			     struct nlattr **tb)
  {
  	return 1;
  }
  
  static int ipmr_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
  			  struct fib_rule_hdr *frh)
  {
  	frh->dst_len = 0;
  	frh->src_len = 0;
  	frh->tos     = 0;
  	return 0;
  }

  static const struct fib_rules_ops __net_initdata ipmr_rules_ops_template = {

  	.family		= RTNL_FAMILY_IPMR,

  	.rule_size	= sizeof(struct ipmr_rule),
  	.addr_size	= sizeof(u32),
  	.action		= ipmr_rule_action,
  	.match		= ipmr_rule_match,
  	.configure	= ipmr_rule_configure,
  	.compare	= ipmr_rule_compare,
  	.default_pref	= fib_default_rule_pref,
  	.fill		= ipmr_rule_fill,
  	.nlgroup	= RTNLGRP_IPV4_RULE,
  	.policy		= ipmr_rule_policy,
  	.owner		= THIS_MODULE,
  };
  
  static int __net_init ipmr_rules_init(struct net *net)
  {
  	struct fib_rules_ops *ops;
  	struct mr_table *mrt;
  	int err;
  
  	ops = fib_rules_register(&ipmr_rules_ops_template, net);
  	if (IS_ERR(ops))
  		return PTR_ERR(ops);
  
  	INIT_LIST_HEAD(&net->ipv4.mr_tables);
  
  	mrt = ipmr_new_table(net, RT_TABLE_DEFAULT);
  	if (mrt == NULL) {
  		err = -ENOMEM;
  		goto err1;
  	}
  
  	err = fib_default_rule_add(ops, 0x7fff, RT_TABLE_DEFAULT, 0);
  	if (err < 0)
  		goto err2;
  
  	net->ipv4.mr_rules_ops = ops;
  	return 0;
  
  err2:
  	kfree(mrt);
  err1:
  	fib_rules_unregister(ops);
  	return err;
  }
  
  static void __net_exit ipmr_rules_exit(struct net *net)
  {
  	struct mr_table *mrt, *next;

  	list_for_each_entry_safe(mrt, next, &net->ipv4.mr_tables, list) {
  		list_del(&mrt->list);

  		kfree(mrt);

  	}

  	fib_rules_unregister(net->ipv4.mr_rules_ops);
  }
  #else
  #define ipmr_for_each_table(mrt, net) \
  	for (mrt = net->ipv4.mrt; mrt; mrt = NULL)
  
  static struct mr_table *ipmr_get_table(struct net *net, u32 id)
  {
  	return net->ipv4.mrt;
  }

  static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,

  			   struct mr_table **mrt)
  {
  	*mrt = net->ipv4.mrt;
  	return 0;
  }
  
  static int __net_init ipmr_rules_init(struct net *net)
  {
  	net->ipv4.mrt = ipmr_new_table(net, RT_TABLE_DEFAULT);
  	return net->ipv4.mrt ? 0 : -ENOMEM;
  }
  
  static void __net_exit ipmr_rules_exit(struct net *net)
  {
  	kfree(net->ipv4.mrt);
  }
  #endif
  
  static struct mr_table *ipmr_new_table(struct net *net, u32 id)
  {
  	struct mr_table *mrt;
  	unsigned int i;

  	mrt = ipmr_get_table(net, id);
  	if (mrt != NULL)
  		return mrt;
  
  	mrt = kzalloc(sizeof(*mrt), GFP_KERNEL);
  	if (mrt == NULL)
  		return NULL;

  	write_pnet(&mrt->net, net);

  	mrt->id = id;
  
  	/* Forwarding cache */
  	for (i = 0; i < MFC_LINES; i++)
  		INIT_LIST_HEAD(&mrt->mfc_cache_array[i]);
  
  	INIT_LIST_HEAD(&mrt->mfc_unres_queue);
  
  	setup_timer(&mrt->ipmr_expire_timer, ipmr_expire_process,
  		    (unsigned long)mrt);
  
  #ifdef CONFIG_IP_PIMSM
  	mrt->mroute_reg_vif_num = -1;
  #endif
  #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
  	list_add_tail_rcu(&mrt->list, &net->ipv4.mr_tables);
  #endif
  	return mrt;
  }

  
  /* Service routines creating virtual interfaces: DVMRP tunnels and PIMREG */

  static void ipmr_del_tunnel(struct net_device *dev, struct vifctl *v)
  {

  	struct net *net = dev_net(dev);

  	dev_close(dev);

  	dev = __dev_get_by_name(net, "tunl0");

  	if (dev) {

  		const struct net_device_ops *ops = dev->netdev_ops;

  		struct ifreq ifr;

  		struct ip_tunnel_parm p;
  
  		memset(&p, 0, sizeof(p));
  		p.iph.daddr = v->vifc_rmt_addr.s_addr;
  		p.iph.saddr = v->vifc_lcl_addr.s_addr;
  		p.iph.version = 4;
  		p.iph.ihl = 5;
  		p.iph.protocol = IPPROTO_IPIP;
  		sprintf(p.name, "dvmrp%d", v->vifc_vifi);
  		ifr.ifr_ifru.ifru_data = (__force void __user *)&p;

  		if (ops->ndo_do_ioctl) {
  			mm_segment_t oldfs = get_fs();
  
  			set_fs(KERNEL_DS);
  			ops->ndo_do_ioctl(dev, &ifr, SIOCDELTUNNEL);
  			set_fs(oldfs);
  		}

  	}
  }

  static

  struct net_device *ipmr_new_tunnel(struct net *net, struct vifctl *v)

  {
  	struct net_device  *dev;

  	dev = __dev_get_by_name(net, "tunl0");

  
  	if (dev) {

  		const struct net_device_ops *ops = dev->netdev_ops;

  		int err;
  		struct ifreq ifr;

  		struct ip_tunnel_parm p;
  		struct in_device  *in_dev;
  
  		memset(&p, 0, sizeof(p));
  		p.iph.daddr = v->vifc_rmt_addr.s_addr;
  		p.iph.saddr = v->vifc_lcl_addr.s_addr;
  		p.iph.version = 4;
  		p.iph.ihl = 5;
  		p.iph.protocol = IPPROTO_IPIP;
  		sprintf(p.name, "dvmrp%d", v->vifc_vifi);

  		ifr.ifr_ifru.ifru_data = (__force void __user *)&p;

  		if (ops->ndo_do_ioctl) {
  			mm_segment_t oldfs = get_fs();
  
  			set_fs(KERNEL_DS);
  			err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
  			set_fs(oldfs);

  		} else {

  			err = -EOPNOTSUPP;

  		}

  		dev = NULL;

  		if (err == 0 &&
  		    (dev = __dev_get_by_name(net, p.name)) != NULL) {

  			dev->flags |= IFF_MULTICAST;

  			in_dev = __in_dev_get_rtnl(dev);

  			if (in_dev == NULL)

  				goto failure;

  
  			ipv4_devconf_setall(in_dev);
  			IPV4_DEVCONF(in_dev->cnf, RP_FILTER) = 0;

  
  			if (dev_open(dev))
  				goto failure;

  			dev_hold(dev);

  		}
  	}
  	return dev;
  
  failure:
  	/* allow the register to be completed before unregistering. */
  	rtnl_unlock();
  	rtnl_lock();
  
  	unregister_netdevice(dev);
  	return NULL;
  }
  
  #ifdef CONFIG_IP_PIMSM

  static netdev_tx_t reg_vif_xmit(struct sk_buff *skb, struct net_device *dev)

  {

  	struct net *net = dev_net(dev);

  	struct mr_table *mrt;

  	struct flowi4 fl4 = {
  		.flowi4_oif	= dev->ifindex,
  		.flowi4_iif	= skb->skb_iif,
  		.flowi4_mark	= skb->mark,

  	};
  	int err;

  	err = ipmr_fib_lookup(net, &fl4, &mrt);

  	if (err < 0) {
  		kfree_skb(skb);

  		return err;

  	}

  	read_lock(&mrt_lock);

  	dev->stats.tx_bytes += skb->len;
  	dev->stats.tx_packets++;

  	ipmr_cache_report(mrt, skb, mrt->mroute_reg_vif_num, IGMPMSG_WHOLEPKT);

  	read_unlock(&mrt_lock);
  	kfree_skb(skb);

  	return NETDEV_TX_OK;

  }

  static const struct net_device_ops reg_vif_netdev_ops = {
  	.ndo_start_xmit	= reg_vif_xmit,
  };

  static void reg_vif_setup(struct net_device *dev)
  {
  	dev->type		= ARPHRD_PIMREG;

  	dev->mtu		= ETH_DATA_LEN - sizeof(struct iphdr) - 8;

  	dev->flags		= IFF_NOARP;

  	dev->netdev_ops		= &reg_vif_netdev_ops,

  	dev->destructor		= free_netdev;

  	dev->features		|= NETIF_F_NETNS_LOCAL;

  }

  static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)

  {
  	struct net_device *dev;
  	struct in_device *in_dev;

  	char name[IFNAMSIZ];

  	if (mrt->id == RT_TABLE_DEFAULT)
  		sprintf(name, "pimreg");
  	else
  		sprintf(name, "pimreg%u", mrt->id);

  	dev = alloc_netdev(0, name, reg_vif_setup);

  
  	if (dev == NULL)
  		return NULL;

  	dev_net_set(dev, net);

  	if (register_netdevice(dev)) {
  		free_netdev(dev);
  		return NULL;
  	}
  	dev->iflink = 0;

  	rcu_read_lock();

  	in_dev = __in_dev_get_rcu(dev);
  	if (!in_dev) {

  		rcu_read_unlock();

  		goto failure;

  	}

  	ipv4_devconf_setall(in_dev);
  	IPV4_DEVCONF(in_dev->cnf, RP_FILTER) = 0;
  	rcu_read_unlock();

  
  	if (dev_open(dev))
  		goto failure;

  	dev_hold(dev);

  	return dev;
  
  failure:
  	/* allow the register to be completed before unregistering. */
  	rtnl_unlock();
  	rtnl_lock();
  
  	unregister_netdevice(dev);
  	return NULL;
  }
  #endif
  
  /*
   *	Delete a VIF entry

   *	@notify: Set to 1, if the caller is a notifier_call

   */

  static int vif_delete(struct mr_table *mrt, int vifi, int notify,

  		      struct list_head *head)

  {
  	struct vif_device *v;
  	struct net_device *dev;
  	struct in_device *in_dev;

  	if (vifi < 0 || vifi >= mrt->maxvif)

  		return -EADDRNOTAVAIL;

  	v = &mrt->vif_table[vifi];

  
  	write_lock_bh(&mrt_lock);
  	dev = v->dev;
  	v->dev = NULL;
  
  	if (!dev) {
  		write_unlock_bh(&mrt_lock);
  		return -EADDRNOTAVAIL;
  	}
  
  #ifdef CONFIG_IP_PIMSM

  	if (vifi == mrt->mroute_reg_vif_num)
  		mrt->mroute_reg_vif_num = -1;

  #endif

  	if (vifi + 1 == mrt->maxvif) {

  		int tmp;

  
  		for (tmp = vifi - 1; tmp >= 0; tmp--) {

  			if (VIF_EXISTS(mrt, tmp))

  				break;
  		}

  		mrt->maxvif = tmp+1;

  	}
  
  	write_unlock_bh(&mrt_lock);
  
  	dev_set_allmulti(dev, -1);

  	in_dev = __in_dev_get_rtnl(dev);
  	if (in_dev) {

  		IPV4_DEVCONF(in_dev->cnf, MC_FORWARDING)--;

  		ip_rt_multicast_event(in_dev);
  	}

  	if (v->flags & (VIFF_TUNNEL | VIFF_REGISTER) && !notify)

  		unregister_netdevice_queue(dev, head);

  
  	dev_put(dev);
  	return 0;
  }

  static void ipmr_cache_free_rcu(struct rcu_head *head)

  {

  	struct mfc_cache *c = container_of(head, struct mfc_cache, rcu);

  	kmem_cache_free(mrt_cachep, c);
  }

  static inline void ipmr_cache_free(struct mfc_cache *c)
  {
  	call_rcu(&c->rcu, ipmr_cache_free_rcu);
  }

  /* Destroy an unresolved cache entry, killing queued skbs

   * and reporting error to netlink readers.

   */

  static void ipmr_destroy_unres(struct mr_table *mrt, struct mfc_cache *c)

  {

  	struct net *net = read_pnet(&mrt->net);

  	struct sk_buff *skb;

  	struct nlmsgerr *e;

  	atomic_dec(&mrt->cache_resolve_queue_len);

  	while ((skb = skb_dequeue(&c->mfc_un.unres.unresolved))) {

  		if (ip_hdr(skb)->version == 0) {

  			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct iphdr));
  			nlh->nlmsg_type = NLMSG_ERROR;
  			nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
  			skb_trim(skb, nlh->nlmsg_len);

  			e = NLMSG_DATA(nlh);
  			e->error = -ETIMEDOUT;
  			memset(&e->msg, 0, sizeof(e->msg));

  			rtnl_unicast(skb, net, NETLINK_CB(skb).pid);

  		} else {

  			kfree_skb(skb);

  		}

  	}

  	ipmr_cache_free(c);

  }

  /* Timer process for the unresolved queue. */

  static void ipmr_expire_process(unsigned long arg)

  {

  	struct mr_table *mrt = (struct mr_table *)arg;

  	unsigned long now;
  	unsigned long expires;

  	struct mfc_cache *c, *next;

  
  	if (!spin_trylock(&mfc_unres_lock)) {

  		mod_timer(&mrt->ipmr_expire_timer, jiffies+HZ/10);

  		return;
  	}

  	if (list_empty(&mrt->mfc_unres_queue))

  		goto out;
  
  	now = jiffies;
  	expires = 10*HZ;

  	list_for_each_entry_safe(c, next, &mrt->mfc_unres_queue, list) {

  		if (time_after(c->mfc_un.unres.expires, now)) {
  			unsigned long interval = c->mfc_un.unres.expires - now;
  			if (interval < expires)
  				expires = interval;

  			continue;
  		}

  		list_del(&c->list);

  		ipmr_destroy_unres(mrt, c);

  	}

  	if (!list_empty(&mrt->mfc_unres_queue))
  		mod_timer(&mrt->ipmr_expire_timer, jiffies + expires);

  
  out:
  	spin_unlock(&mfc_unres_lock);
  }
  
  /* Fill oifs list. It is called under write locked mrt_lock. */

  static void ipmr_update_thresholds(struct mr_table *mrt, struct mfc_cache *cache,

  				   unsigned char *ttls)

  {
  	int vifi;
  
  	cache->mfc_un.res.minvif = MAXVIFS;
  	cache->mfc_un.res.maxvif = 0;
  	memset(cache->mfc_un.res.ttls, 255, MAXVIFS);

  	for (vifi = 0; vifi < mrt->maxvif; vifi++) {
  		if (VIF_EXISTS(mrt, vifi) &&

  		    ttls[vifi] && ttls[vifi] < 255) {

  			cache->mfc_un.res.ttls[vifi] = ttls[vifi];
  			if (cache->mfc_un.res.minvif > vifi)
  				cache->mfc_un.res.minvif = vifi;
  			if (cache->mfc_un.res.maxvif <= vifi)
  				cache->mfc_un.res.maxvif = vifi + 1;
  		}
  	}
  }

  static int vif_add(struct net *net, struct mr_table *mrt,
  		   struct vifctl *vifc, int mrtsock)

  {
  	int vifi = vifc->vifc_vifi;

  	struct vif_device *v = &mrt->vif_table[vifi];

  	struct net_device *dev;
  	struct in_device *in_dev;

  	int err;

  
  	/* Is vif busy ? */

  	if (VIF_EXISTS(mrt, vifi))

  		return -EADDRINUSE;
  
  	switch (vifc->vifc_flags) {
  #ifdef CONFIG_IP_PIMSM
  	case VIFF_REGISTER:
  		/*
  		 * Special Purpose VIF in PIM
  		 * All the packets will be sent to the daemon
  		 */

  		if (mrt->mroute_reg_vif_num >= 0)

  			return -EADDRINUSE;

  		dev = ipmr_reg_vif(net, mrt);

  		if (!dev)
  			return -ENOBUFS;

  		err = dev_set_allmulti(dev, 1);
  		if (err) {
  			unregister_netdevice(dev);

  			dev_put(dev);

  			return err;
  		}

  		break;
  #endif

  	case VIFF_TUNNEL:

  		dev = ipmr_new_tunnel(net, vifc);

  		if (!dev)
  			return -ENOBUFS;

  		err = dev_set_allmulti(dev, 1);
  		if (err) {
  			ipmr_del_tunnel(dev, vifc);

  			dev_put(dev);

  			return err;
  		}

  		break;

  
  	case VIFF_USE_IFINDEX:

  	case 0:

  		if (vifc->vifc_flags == VIFF_USE_IFINDEX) {
  			dev = dev_get_by_index(net, vifc->vifc_lcl_ifindex);

  			if (dev && __in_dev_get_rtnl(dev) == NULL) {

  				dev_put(dev);
  				return -EADDRNOTAVAIL;
  			}

  		} else {

  			dev = ip_dev_find(net, vifc->vifc_lcl_addr.s_addr);

  		}

  		if (!dev)
  			return -EADDRNOTAVAIL;

  		err = dev_set_allmulti(dev, 1);

  		if (err) {
  			dev_put(dev);

  			return err;

  		}

  		break;
  	default:
  		return -EINVAL;
  	}

  	in_dev = __in_dev_get_rtnl(dev);
  	if (!in_dev) {

  		dev_put(dev);

  		return -EADDRNOTAVAIL;

  	}

  	IPV4_DEVCONF(in_dev->cnf, MC_FORWARDING)++;

  	ip_rt_multicast_event(in_dev);

  	/* Fill in the VIF structures */

  	v->rate_limit = vifc->vifc_rate_limit;
  	v->local = vifc->vifc_lcl_addr.s_addr;
  	v->remote = vifc->vifc_rmt_addr.s_addr;
  	v->flags = vifc->vifc_flags;

  	if (!mrtsock)
  		v->flags |= VIFF_STATIC;

  	v->threshold = vifc->vifc_threshold;

  	v->bytes_in = 0;
  	v->bytes_out = 0;
  	v->pkt_in = 0;
  	v->pkt_out = 0;
  	v->link = dev->ifindex;

  	if (v->flags & (VIFF_TUNNEL | VIFF_REGISTER))

  		v->link = dev->iflink;
  
  	/* And finish update writing critical data */
  	write_lock_bh(&mrt_lock);

  	v->dev = dev;

  #ifdef CONFIG_IP_PIMSM

  	if (v->flags & VIFF_REGISTER)

  		mrt->mroute_reg_vif_num = vifi;

  #endif

  	if (vifi+1 > mrt->maxvif)
  		mrt->maxvif = vifi+1;

  	write_unlock_bh(&mrt_lock);
  	return 0;
  }

  /* called with rcu_read_lock() */

  static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt,

  					 __be32 origin,
  					 __be32 mcastgrp)

  {

  	int line = MFC_HASH(mcastgrp, origin);

  	struct mfc_cache *c;

  	list_for_each_entry_rcu(c, &mrt->mfc_cache_array[line], list) {

  		if (c->mfc_origin == origin && c->mfc_mcastgrp == mcastgrp)
  			return c;

  	}

  	return NULL;

  }
  
  /*
   *	Allocate a multicast cache entry
   */

  static struct mfc_cache *ipmr_cache_alloc(void)

  {

  	struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_KERNEL);

  
  	if (c)
  		c->mfc_un.res.minvif = MAXVIFS;

  	return c;
  }

  static struct mfc_cache *ipmr_cache_alloc_unres(void)

  {

  	struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_ATOMIC);

  
  	if (c) {
  		skb_queue_head_init(&c->mfc_un.unres.unresolved);
  		c->mfc_un.unres.expires = jiffies + 10*HZ;
  	}

  	return c;
  }
  
  /*
   *	A cache entry has gone into a resolved state from queued
   */

  static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt,
  			       struct mfc_cache *uc, struct mfc_cache *c)

  {
  	struct sk_buff *skb;

  	struct nlmsgerr *e;

  	/* Play the pending entries through our router */

  	while ((skb = __skb_dequeue(&uc->mfc_un.unres.unresolved))) {

  		if (ip_hdr(skb)->version == 0) {

  			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct iphdr));

  			if (__ipmr_fill_mroute(mrt, skb, c, NLMSG_DATA(nlh)) > 0) {

  				nlh->nlmsg_len = skb_tail_pointer(skb) -
  						 (u8 *)nlh;

  			} else {
  				nlh->nlmsg_type = NLMSG_ERROR;
  				nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
  				skb_trim(skb, nlh->nlmsg_len);

  				e = NLMSG_DATA(nlh);
  				e->error = -EMSGSIZE;
  				memset(&e->msg, 0, sizeof(e->msg));

  			}

  			rtnl_unicast(skb, net, NETLINK_CB(skb).pid);

  		} else {

  			ip_mr_forward(net, mrt, skb, c, 0);

  		}

  	}
  }
  
  /*
   *	Bounce a cache query up to mrouted. We could use netlink for this but mrouted
   *	expects the following bizarre scheme.
   *
   *	Called under mrt_lock.
   */

  static int ipmr_cache_report(struct mr_table *mrt,

  			     struct sk_buff *pkt, vifi_t vifi, int assert)

  {
  	struct sk_buff *skb;

  	const int ihl = ip_hdrlen(pkt);

  	struct igmphdr *igmp;
  	struct igmpmsg *msg;

  	struct sock *mroute_sk;

  	int ret;
  
  #ifdef CONFIG_IP_PIMSM
  	if (assert == IGMPMSG_WHOLEPKT)
  		skb = skb_realloc_headroom(pkt, sizeof(struct iphdr));
  	else
  #endif
  		skb = alloc_skb(128, GFP_ATOMIC);

  	if (!skb)

  		return -ENOBUFS;
  
  #ifdef CONFIG_IP_PIMSM
  	if (assert == IGMPMSG_WHOLEPKT) {
  		/* Ugly, but we have no choice with this interface.

  		 * Duplicate old header, fix ihl, length etc.
  		 * And all this only to mangle msg->im_msgtype and
  		 * to set msg->im_mbz to "mbz" :-)

  		 */

  		skb_push(skb, sizeof(struct iphdr));
  		skb_reset_network_header(skb);

  		skb_reset_transport_header(skb);

  		msg = (struct igmpmsg *)skb_network_header(skb);

  		memcpy(msg, skb_network_header(pkt), sizeof(struct iphdr));

  		msg->im_msgtype = IGMPMSG_WHOLEPKT;
  		msg->im_mbz = 0;

  		msg->im_vif = mrt->mroute_reg_vif_num;

  		ip_hdr(skb)->ihl = sizeof(struct iphdr) >> 2;
  		ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(pkt)->tot_len) +
  					     sizeof(struct iphdr));

  	} else

  #endif

  	{

  	/* Copy the IP header */

  	skb->network_header = skb->tail;

  	skb_put(skb, ihl);

  	skb_copy_to_linear_data(skb, pkt->data, ihl);

  	ip_hdr(skb)->protocol = 0;	/* Flag to the kernel this is a route add */

  	msg = (struct igmpmsg *)skb_network_header(skb);

  	msg->im_vif = vifi;

  	skb_dst_set(skb, dst_clone(skb_dst(pkt)));

  	/* Add our header */

  	igmp = (struct igmphdr *)skb_put(skb, sizeof(struct igmphdr));

  	igmp->type	=
  	msg->im_msgtype = assert;

  	igmp->code	= 0;
  	ip_hdr(skb)->tot_len = htons(skb->len);		/* Fix the length */

  	skb->transport_header = skb->network_header;

  	}

  	rcu_read_lock();
  	mroute_sk = rcu_dereference(mrt->mroute_sk);
  	if (mroute_sk == NULL) {
  		rcu_read_unlock();

  		kfree_skb(skb);
  		return -EINVAL;
  	}

  	/* Deliver to mrouted */

  	ret = sock_queue_rcv_skb(mroute_sk, skb);
  	rcu_read_unlock();

  	if (ret < 0) {

  		if (net_ratelimit())
  			printk(KERN_WARNING "mroute: pending queue full, dropping entries.
  ");
  		kfree_skb(skb);
  	}
  
  	return ret;
  }
  
  /*
   *	Queue a packet for resolution. It gets locked cache entry!
   */

  static int

  ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi, struct sk_buff *skb)

  {

  	bool found = false;

  	int err;
  	struct mfc_cache *c;

  	const struct iphdr *iph = ip_hdr(skb);

  
  	spin_lock_bh(&mfc_unres_lock);

  	list_for_each_entry(c, &mrt->mfc_unres_queue, list) {

  		if (c->mfc_mcastgrp == iph->daddr &&

  		    c->mfc_origin == iph->saddr) {
  			found = true;

  			break;

  		}

  	}

  	if (!found) {

  		/* Create a new entry if allowable */

  		if (atomic_read(&mrt->cache_resolve_queue_len) >= 10 ||

  		    (c = ipmr_cache_alloc_unres()) == NULL) {

  			spin_unlock_bh(&mfc_unres_lock);
  
  			kfree_skb(skb);
  			return -ENOBUFS;
  		}

  		/* Fill in the new cache entry */

  		c->mfc_parent	= -1;
  		c->mfc_origin	= iph->saddr;
  		c->mfc_mcastgrp	= iph->daddr;

  		/* Reflect first query at mrouted. */

  		err = ipmr_cache_report(mrt, skb, vifi, IGMPMSG_NOCACHE);

  		if (err < 0) {

  			/* If the report failed throw the cache entry

  			   out - Brad Parker
  			 */
  			spin_unlock_bh(&mfc_unres_lock);

  			ipmr_cache_free(c);

  			kfree_skb(skb);
  			return err;
  		}

  		atomic_inc(&mrt->cache_resolve_queue_len);
  		list_add(&c->list, &mrt->mfc_unres_queue);

  		if (atomic_read(&mrt->cache_resolve_queue_len) == 1)
  			mod_timer(&mrt->ipmr_expire_timer, c->mfc_un.unres.expires);

  	}

  	/* See if we can append the packet */
  
  	if (c->mfc_un.unres.unresolved.qlen > 3) {

  		kfree_skb(skb);
  		err = -ENOBUFS;
  	} else {

  		skb_queue_tail(&c->mfc_un.unres.unresolved, skb);

  		err = 0;
  	}
  
  	spin_unlock_bh(&mfc_unres_lock);
  	return err;
  }
  
  /*
   *	MFC cache manipulation by user space mroute daemon
   */

  static int ipmr_mfc_delete(struct mr_table *mrt, struct mfcctl *mfc)

  {
  	int line;

  	struct mfc_cache *c, *next;

  	line = MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);

  	list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[line], list) {

  		if (c->mfc_origin == mfc->mfcc_origin.s_addr &&
  		    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {

  			list_del_rcu(&c->list);

  			ipmr_cache_free(c);

  			return 0;
  		}
  	}
  	return -ENOENT;
  }

  static int ipmr_mfc_add(struct net *net, struct mr_table *mrt,
  			struct mfcctl *mfc, int mrtsock)

  {

  	bool found = false;

  	int line;

  	struct mfc_cache *uc, *c;

  	if (mfc->mfcc_parent >= MAXVIFS)
  		return -ENFILE;

  	line = MFC_HASH(mfc->mfcc_mcastgrp.s_addr, mfc->mfcc_origin.s_addr);

  	list_for_each_entry(c, &mrt->mfc_cache_array[line], list) {

  		if (c->mfc_origin == mfc->mfcc_origin.s_addr &&

  		    c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) {
  			found = true;

  			break;

  		}

  	}

  	if (found) {

  		write_lock_bh(&mrt_lock);
  		c->mfc_parent = mfc->mfcc_parent;

  		ipmr_update_thresholds(mrt, c, mfc->mfcc_ttls);

  		if (!mrtsock)
  			c->mfc_flags |= MFC_STATIC;
  		write_unlock_bh(&mrt_lock);
  		return 0;
  	}

  	if (!ipv4_is_multicast(mfc->mfcc_mcastgrp.s_addr))

  		return -EINVAL;

  	c = ipmr_cache_alloc();

  	if (c == NULL)

  		return -ENOMEM;

  	c->mfc_origin = mfc->mfcc_origin.s_addr;
  	c->mfc_mcastgrp = mfc->mfcc_mcastgrp.s_addr;
  	c->mfc_parent = mfc->mfcc_parent;

  	ipmr_update_thresholds(mrt, c, mfc->mfcc_ttls);

  	if (!mrtsock)
  		c->mfc_flags |= MFC_STATIC;

  	list_add_rcu(&c->list, &mrt->mfc_cache_array[line]);

  
  	/*
  	 *	Check to see if we resolved a queued list. If so we
  	 *	need to send on the frames and tidy up.
  	 */

  	found = false;

  	spin_lock_bh(&mfc_unres_lock);

  	list_for_each_entry(uc, &mrt->mfc_unres_queue, list) {

  		if (uc->mfc_origin == c->mfc_origin &&

  		    uc->mfc_mcastgrp == c->mfc_mcastgrp) {

  			list_del(&uc->list);

  			atomic_dec(&mrt->cache_resolve_queue_len);

  			found = true;

  			break;
  		}
  	}

  	if (list_empty(&mrt->mfc_unres_queue))
  		del_timer(&mrt->ipmr_expire_timer);

  	spin_unlock_bh(&mfc_unres_lock);

  	if (found) {

  		ipmr_cache_resolve(net, mrt, uc, c);

  		ipmr_cache_free(uc);

  	}
  	return 0;
  }
  
  /*
   *	Close the multicast socket, and clear the vif tables etc
   */

  static void mroute_clean_tables(struct mr_table *mrt)

  {
  	int i;

  	LIST_HEAD(list);

  	struct mfc_cache *c, *next;

  	/* Shut down all active vif entries */

  	for (i = 0; i < mrt->maxvif; i++) {

  		if (!(mrt->vif_table[i].flags & VIFF_STATIC))

  			vif_delete(mrt, i, 0, &list);

  	}

  	unregister_netdevice_many(&list);

  	/* Wipe the cache */

  	for (i = 0; i < MFC_LINES; i++) {

  		list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[i], list) {

  			if (c->mfc_flags & MFC_STATIC)

  				continue;

  			list_del_rcu(&c->list);

  			ipmr_cache_free(c);

  		}
  	}

  	if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {

  		spin_lock_bh(&mfc_unres_lock);

  		list_for_each_entry_safe(c, next, &mrt->mfc_unres_queue, list) {

  			list_del(&c->list);

  			ipmr_destroy_unres(mrt, c);

  		}
  		spin_unlock_bh(&mfc_unres_lock);
  	}
  }

  /* called from ip_ra_control(), before an RCU grace period,
   * we dont need to call synchronize_rcu() here
   */

  static void mrtsock_destruct(struct sock *sk)
  {

  	struct net *net = sock_net(sk);

  	struct mr_table *mrt;

  	rtnl_lock();

  	ipmr_for_each_table(mrt, net) {

  		if (sk == rtnl_dereference(mrt->mroute_sk)) {

  			IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;

  			RCU_INIT_POINTER(mrt->mroute_sk, NULL);

  			mroute_clean_tables(mrt);
  		}

  	}
  	rtnl_unlock();
  }
  
  /*
   *	Socket options and virtual interface manipulation. The whole
   *	virtual interface system is a complete heap, but unfortunately
   *	that's how BSD mrouted happens to think. Maybe one day with a proper
   *	MOSPF/PIM router set up we can clean this up.
   */

  int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, unsigned int optlen)

  {
  	int ret;
  	struct vifctl vif;
  	struct mfcctl mfc;

  	struct net *net = sock_net(sk);

  	struct mr_table *mrt;
  
  	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
  	if (mrt == NULL)
  		return -ENOENT;

  	if (optname != MRT_INIT) {

  		if (sk != rcu_access_pointer(mrt->mroute_sk) &&

  		    !capable(CAP_NET_ADMIN))

  			return -EACCES;
  	}

  	switch (optname) {
  	case MRT_INIT:
  		if (sk->sk_type != SOCK_RAW ||

  		    inet_sk(sk)->inet_num != IPPROTO_IGMP)

  			return -EOPNOTSUPP;

  		if (optlen != sizeof(int))

  			return -ENOPROTOOPT;

  		rtnl_lock();

  		if (rtnl_dereference(mrt->mroute_sk)) {

  			rtnl_unlock();

  			return -EADDRINUSE;
  		}
  
  		ret = ip_ra_control(sk, 1, mrtsock_destruct);
  		if (ret == 0) {

  			rcu_assign_pointer(mrt->mroute_sk, sk);

  			IPV4_DEVCONF_ALL(net, MC_FORWARDING)++;

  		}
  		rtnl_unlock();
  		return ret;
  	case MRT_DONE:

  		if (sk != rcu_access_pointer(mrt->mroute_sk))

  			return -EACCES;
  		return ip_ra_control(sk, 0, NULL);
  	case MRT_ADD_VIF:
  	case MRT_DEL_VIF:

  		if (optlen != sizeof(vif))

  			return -EINVAL;

  		if (copy_from_user(&vif, optval, sizeof(vif)))

  			return -EFAULT;
  		if (vif.vifc_vifi >= MAXVIFS)
  			return -ENFILE;
  		rtnl_lock();

  		if (optname == MRT_ADD_VIF) {

  			ret = vif_add(net, mrt, &vif,
  				      sk == rtnl_dereference(mrt->mroute_sk));

  		} else {

  			ret = vif_delete(mrt, vif.vifc_vifi, 0, NULL);

  		}
  		rtnl_unlock();
  		return ret;

  
  		/*
  		 *	Manipulate the forwarding caches. These live
  		 *	in a sort of kernel/user symbiosis.
  		 */

  	case MRT_ADD_MFC:
  	case MRT_DEL_MFC:

  		if (optlen != sizeof(mfc))

  			return -EINVAL;

  		if (copy_from_user(&mfc, optval, sizeof(mfc)))

  			return -EFAULT;
  		rtnl_lock();

  		if (optname == MRT_DEL_MFC)

  			ret = ipmr_mfc_delete(mrt, &mfc);

  		else

  			ret = ipmr_mfc_add(net, mrt, &mfc,
  					   sk == rtnl_dereference(mrt->mroute_sk));

  		rtnl_unlock();
  		return ret;

  		/*
  		 *	Control PIM assert.
  		 */

  	case MRT_ASSERT:
  	{
  		int v;

  		if (get_user(v, (int __user *)optval))

  			return -EFAULT;

  		mrt->mroute_do_assert = (v) ? 1 : 0;

  		return 0;
  	}

  #ifdef CONFIG_IP_PIMSM

  	case MRT_PIM:
  	{

  		int v;

  		if (get_user(v, (int __user *)optval))

  			return -EFAULT;

  		v = (v) ? 1 : 0;

  		rtnl_lock();
  		ret = 0;

  		if (v != mrt->mroute_do_pim) {
  			mrt->mroute_do_pim = v;
  			mrt->mroute_do_assert = v;

  		}

  		rtnl_unlock();
  		return ret;
  	}

  #endif

  #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
  	case MRT_TABLE:
  	{
  		u32 v;
  
  		if (optlen != sizeof(u32))
  			return -EINVAL;
  		if (get_user(v, (u32 __user *)optval))
  			return -EFAULT;

  
  		rtnl_lock();
  		ret = 0;

  		if (sk == rtnl_dereference(mrt->mroute_sk)) {
  			ret = -EBUSY;
  		} else {
  			if (!ipmr_new_table(net, v))
  				ret = -ENOMEM;
  			raw_sk(sk)->ipmr_table = v;
  		}

  		rtnl_unlock();
  		return ret;
  	}
  #endif

  	/*
  	 *	Spurious command, or MRT_VERSION which you cannot
  	 *	set.
  	 */
  	default:
  		return -ENOPROTOOPT;

  	}
  }
  
  /*
   *	Getsock opt support for the multicast routing system.
   */

  int ip_mroute_getsockopt(struct sock *sk, int optname, char __user *optval, int __user *optlen)

  {
  	int olr;
  	int val;

  	struct net *net = sock_net(sk);

  	struct mr_table *mrt;
  
  	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
  	if (mrt == NULL)
  		return -ENOENT;

  	if (optname != MRT_VERSION &&

  #ifdef CONFIG_IP_PIMSM

  	   optname != MRT_PIM &&

  #endif

  	   optname != MRT_ASSERT)

  		return -ENOPROTOOPT;
  
  	if (get_user(olr, optlen))
  		return -EFAULT;
  
  	olr = min_t(unsigned int, olr, sizeof(int));
  	if (olr < 0)
  		return -EINVAL;

  	if (put_user(olr, optlen))

  		return -EFAULT;

  	if (optname == MRT_VERSION)
  		val = 0x0305;

  #ifdef CONFIG_IP_PIMSM

  	else if (optname == MRT_PIM)

  		val = mrt->mroute_do_pim;

  #endif
  	else

  		val = mrt->mroute_do_assert;

  	if (copy_to_user(optval, &val, olr))

  		return -EFAULT;
  	return 0;
  }
  
  /*
   *	The IP multicast ioctl support routines.
   */

  int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
  {
  	struct sioc_sg_req sr;
  	struct sioc_vif_req vr;
  	struct vif_device *vif;
  	struct mfc_cache *c;

  	struct net *net = sock_net(sk);

  	struct mr_table *mrt;
  
  	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
  	if (mrt == NULL)
  		return -ENOENT;

  	switch (cmd) {
  	case SIOCGETVIFCNT:

  		if (copy_from_user(&vr, arg, sizeof(vr)))

  			return -EFAULT;

  		if (vr.vifi >= mrt->maxvif)

  			return -EINVAL;
  		read_lock(&mrt_lock);

  		vif = &mrt->vif_table[vr.vifi];
  		if (VIF_EXISTS(mrt, vr.vifi)) {

  			vr.icount = vif->pkt_in;
  			vr.ocount = vif->pkt_out;
  			vr.ibytes = vif->bytes_in;
  			vr.obytes = vif->bytes_out;

  			read_unlock(&mrt_lock);

  			if (copy_to_user(arg, &vr, sizeof(vr)))

  				return -EFAULT;
  			return 0;
  		}
  		read_unlock(&mrt_lock);
  		return -EADDRNOTAVAIL;
  	case SIOCGETSGCNT:

  		if (copy_from_user(&sr, arg, sizeof(sr)))

  			return -EFAULT;

  		rcu_read_lock();

  		c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);

  		if (c) {
  			sr.pktcnt = c->mfc_un.res.pkt;
  			sr.bytecnt = c->mfc_un.res.bytes;
  			sr.wrong_if = c->mfc_un.res.wrong_if;

  			rcu_read_unlock();

  			if (copy_to_user(arg, &sr, sizeof(sr)))

  				return -EFAULT;
  			return 0;
  		}

  		rcu_read_unlock();

  		return -EADDRNOTAVAIL;
  	default:
  		return -ENOIOCTLCMD;

  	}
  }

  #ifdef CONFIG_COMPAT
  struct compat_sioc_sg_req {
  	struct in_addr src;
  	struct in_addr grp;
  	compat_ulong_t pktcnt;
  	compat_ulong_t bytecnt;
  	compat_ulong_t wrong_if;
  };

  struct compat_sioc_vif_req {
  	vifi_t	vifi;		/* Which iface */
  	compat_ulong_t icount;
  	compat_ulong_t ocount;
  	compat_ulong_t ibytes;
  	compat_ulong_t obytes;
  };

  int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
  {

  	struct compat_sioc_sg_req sr;

  	struct compat_sioc_vif_req vr;
  	struct vif_device *vif;

  	struct mfc_cache *c;
  	struct net *net = sock_net(sk);
  	struct mr_table *mrt;
  
  	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
  	if (mrt == NULL)
  		return -ENOENT;
  
  	switch (cmd) {

  	case SIOCGETVIFCNT:
  		if (copy_from_user(&vr, arg, sizeof(vr)))
  			return -EFAULT;
  		if (vr.vifi >= mrt->maxvif)
  			return -EINVAL;
  		read_lock(&mrt_lock);
  		vif = &mrt->vif_table[vr.vifi];
  		if (VIF_EXISTS(mrt, vr.vifi)) {
  			vr.icount = vif->pkt_in;
  			vr.ocount = vif->pkt_out;
  			vr.ibytes = vif->bytes_in;
  			vr.obytes = vif->bytes_out;
  			read_unlock(&mrt_lock);
  
  			if (copy_to_user(arg, &vr, sizeof(vr)))
  				return -EFAULT;
  			return 0;
  		}
  		read_unlock(&mrt_lock);
  		return -EADDRNOTAVAIL;

  	case SIOCGETSGCNT:
  		if (copy_from_user(&sr, arg, sizeof(sr)))
  			return -EFAULT;
  
  		rcu_read_lock();
  		c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);
  		if (c) {
  			sr.pktcnt = c->mfc_un.res.pkt;
  			sr.bytecnt = c->mfc_un.res.bytes;
  			sr.wrong_if = c->mfc_un.res.wrong_if;
  			rcu_read_unlock();
  
  			if (copy_to_user(arg, &sr, sizeof(sr)))
  				return -EFAULT;
  			return 0;
  		}
  		rcu_read_unlock();
  		return -EADDRNOTAVAIL;
  	default:
  		return -ENOIOCTLCMD;
  	}
  }
  #endif

  
  static int ipmr_device_event(struct notifier_block *this, unsigned long event, void *ptr)
  {

  	struct net_device *dev = ptr;

  	struct net *net = dev_net(dev);

  	struct mr_table *mrt;

  	struct vif_device *v;
  	int ct;

  	if (event != NETDEV_UNREGISTER)
  		return NOTIFY_DONE;

  
  	ipmr_for_each_table(mrt, net) {
  		v = &mrt->vif_table[0];
  		for (ct = 0; ct < mrt->maxvif; ct++, v++) {
  			if (v->dev == dev)

  				vif_delete(mrt, ct, 1, NULL);

  		}

  	}
  	return NOTIFY_DONE;
  }

  static struct notifier_block ip_mr_notifier = {

  	.notifier_call = ipmr_device_event,
  };
  
  /*

   *	Encapsulate a packet by attaching a valid IPIP header to it.

   *	This avoids tunnel drivers and other mess and gives us the speed so
   *	important for multicast video.
   */

  static void ip_encap(struct sk_buff *skb, __be32 saddr, __be32 daddr)

  {

  	struct iphdr *iph;

  	const struct iphdr *old_iph = ip_hdr(skb);

  
  	skb_push(skb, sizeof(struct iphdr));

  	skb->transport_header = skb->network_header;

  	skb_reset_network_header(skb);

  	iph = ip_hdr(skb);

  	iph->version	=	4;

  	iph->tos	=	old_iph->tos;
  	iph->ttl	=	old_iph->ttl;

  	iph->frag_off	=	0;
  	iph->daddr	=	daddr;
  	iph->saddr	=	saddr;
  	iph->protocol	=	IPPROTO_IPIP;
  	iph->ihl	=	5;
  	iph->tot_len	=	htons(skb->len);

  	ip_select_ident(iph, skb_dst(skb), NULL);

  	ip_send_check(iph);

  	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
  	nf_reset(skb);
  }
  
  static inline int ipmr_forward_finish(struct sk_buff *skb)
  {

  	struct ip_options *opt = &(IPCB(skb)->opt);

  	IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTFORWDATAGRAMS);

  
  	if (unlikely(opt->optlen))
  		ip_forward_options(skb);
  
  	return dst_output(skb);
  }
  
  /*
   *	Processing handlers for ipmr_forward
   */

  static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
  			    struct sk_buff *skb, struct mfc_cache *c, int vifi)

  {