/*
   *	Linux IPv6 multicast routing support for BSD pim6sd
   *	Based on net/ipv4/ipmr.c.
   *
   *	(c) 2004 Mickael Hoerdt, <hoerdt@clarinet.u-strasbg.fr>
   *		LSIIT Laboratory, Strasbourg, France
   *	(c) 2004 Jean-Philippe Andriot, <jean-philippe.andriot@6WIND.com>
   *		6WIND, Paris, France
   *	Copyright (C)2007,2008 USAGI/WIDE Project
   *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
   *
   *	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 <linux/uaccess.h>

  #include <linux/types.h>
  #include <linux/sched.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/inet.h>
  #include <linux/netdevice.h>
  #include <linux/inetdevice.h>

  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>

  #include <linux/init.h>

  #include <linux/slab.h>

  #include <linux/compat.h>

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

  #include <net/raw.h>

  #include <linux/notifier.h>
  #include <linux/if_arp.h>

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

  #include <net/fib_rules.h>

  
  #include <net/ipv6.h>
  #include <net/ip6_route.h>
  #include <linux/mroute6.h>

  #include <linux/pim.h>

  #include <net/addrconf.h>
  #include <linux/netfilter_ipv6.h>

  #include <linux/export.h>

  #include <net/ip6_checksum.h>

  #include <linux/netconf.h>

  struct mr6_table {

  	struct list_head	list;

  	possible_net_t		net;

  	u32			id;

  	struct sock		*mroute6_sk;
  	struct timer_list	ipmr_expire_timer;
  	struct list_head	mfc6_unres_queue;
  	struct list_head	mfc6_cache_array[MFC6_LINES];
  	struct mif_device	vif6_table[MAXMIFS];
  	int			maxvif;
  	atomic_t		cache_resolve_queue_len;

  	bool			mroute_do_assert;
  	bool			mroute_do_pim;

  #ifdef CONFIG_IPV6_PIMSM_V2
  	int			mroute_reg_vif_num;
  #endif
  };

  #include <linux/nospec.h>

  struct ip6mr_rule {
  	struct fib_rule		common;
  };
  
  struct ip6mr_result {
  	struct mr6_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 MIF_EXISTS(_mrt, _idx) ((_mrt)->vif6_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 mr6_table *ip6mr_new_table(struct net *net, u32 id);
  static void ip6mr_free_table(struct mr6_table *mrt);

  static void ip6_mr_forward(struct net *net, struct mr6_table *mrt,
  			   struct sk_buff *skb, struct mfc6_cache *cache);

  static int ip6mr_cache_report(struct mr6_table *mrt, struct sk_buff *pkt,

  			      mifi_t mifi, int assert);

  static int __ip6mr_fill_mroute(struct mr6_table *mrt, struct sk_buff *skb,
  			       struct mfc6_cache *c, struct rtmsg *rtm);

  static void mr6_netlink_event(struct mr6_table *mrt, struct mfc6_cache *mfc,
  			      int cmd);

  static void mrt6msg_netlink_event(struct mr6_table *mrt, struct sk_buff *pkt);

  static int ip6mr_rtm_dumproute(struct sk_buff *skb,
  			       struct netlink_callback *cb);

  static void mroute_clean_tables(struct mr6_table *mrt, bool all);

  static void ipmr_expire_process(unsigned long arg);
  
  #ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES

  #define ip6mr_for_each_table(mrt, net) \

  	list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list)
  
  static struct mr6_table *ip6mr_get_table(struct net *net, u32 id)
  {
  	struct mr6_table *mrt;
  
  	ip6mr_for_each_table(mrt, net) {
  		if (mrt->id == id)
  			return mrt;
  	}
  	return NULL;
  }

  static int ip6mr_fib_lookup(struct net *net, struct flowi6 *flp6,

  			    struct mr6_table **mrt)
  {

  	int err;

  	struct ip6mr_result res;
  	struct fib_lookup_arg arg = {
  		.result = &res,
  		.flags = FIB_LOOKUP_NOREF,
  	};

  	err = fib_rules_lookup(net->ipv6.mr6_rules_ops,
  			       flowi6_to_flowi(flp6), 0, &arg);

  	if (err < 0)
  		return err;
  	*mrt = res.mrt;
  	return 0;
  }
  
  static int ip6mr_rule_action(struct fib_rule *rule, struct flowi *flp,
  			     int flags, struct fib_lookup_arg *arg)
  {
  	struct ip6mr_result *res = arg->result;
  	struct mr6_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 = ip6mr_get_table(rule->fr_net, rule->table);

  	if (!mrt)

  		return -EAGAIN;
  	res->mrt = mrt;
  	return 0;
  }
  
  static int ip6mr_rule_match(struct fib_rule *rule, struct flowi *flp, int flags)
  {
  	return 1;
  }
  
  static const struct nla_policy ip6mr_rule_policy[FRA_MAX + 1] = {
  	FRA_GENERIC_POLICY,
  };
  
  static int ip6mr_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
  				struct fib_rule_hdr *frh, struct nlattr **tb)
  {
  	return 0;
  }
  
  static int ip6mr_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
  			      struct nlattr **tb)
  {
  	return 1;
  }
  
  static int ip6mr_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_initconst ip6mr_rules_ops_template = {

  	.family		= RTNL_FAMILY_IP6MR,
  	.rule_size	= sizeof(struct ip6mr_rule),
  	.addr_size	= sizeof(struct in6_addr),
  	.action		= ip6mr_rule_action,
  	.match		= ip6mr_rule_match,
  	.configure	= ip6mr_rule_configure,
  	.compare	= ip6mr_rule_compare,

  	.fill		= ip6mr_rule_fill,
  	.nlgroup	= RTNLGRP_IPV6_RULE,
  	.policy		= ip6mr_rule_policy,
  	.owner		= THIS_MODULE,
  };
  
  static int __net_init ip6mr_rules_init(struct net *net)
  {
  	struct fib_rules_ops *ops;
  	struct mr6_table *mrt;
  	int err;
  
  	ops = fib_rules_register(&ip6mr_rules_ops_template, net);
  	if (IS_ERR(ops))
  		return PTR_ERR(ops);
  
  	INIT_LIST_HEAD(&net->ipv6.mr6_tables);
  
  	mrt = ip6mr_new_table(net, RT6_TABLE_DFLT);

  	if (!mrt) {

  		err = -ENOMEM;
  		goto err1;
  	}
  
  	err = fib_default_rule_add(ops, 0x7fff, RT6_TABLE_DFLT, 0);
  	if (err < 0)
  		goto err2;
  
  	net->ipv6.mr6_rules_ops = ops;
  	return 0;
  
  err2:

  	ip6mr_free_table(mrt);

  err1:
  	fib_rules_unregister(ops);
  	return err;
  }
  
  static void __net_exit ip6mr_rules_exit(struct net *net)
  {
  	struct mr6_table *mrt, *next;

  	rtnl_lock();

  	list_for_each_entry_safe(mrt, next, &net->ipv6.mr6_tables, list) {
  		list_del(&mrt->list);

  		ip6mr_free_table(mrt);

  	}

  	fib_rules_unregister(net->ipv6.mr6_rules_ops);

  	rtnl_unlock();

  }
  #else
  #define ip6mr_for_each_table(mrt, net) \
  	for (mrt = net->ipv6.mrt6; mrt; mrt = NULL)
  
  static struct mr6_table *ip6mr_get_table(struct net *net, u32 id)
  {
  	return net->ipv6.mrt6;
  }

  static int ip6mr_fib_lookup(struct net *net, struct flowi6 *flp6,

  			    struct mr6_table **mrt)
  {
  	*mrt = net->ipv6.mrt6;
  	return 0;
  }
  
  static int __net_init ip6mr_rules_init(struct net *net)
  {
  	net->ipv6.mrt6 = ip6mr_new_table(net, RT6_TABLE_DFLT);
  	return net->ipv6.mrt6 ? 0 : -ENOMEM;
  }
  
  static void __net_exit ip6mr_rules_exit(struct net *net)
  {

  	rtnl_lock();

  	ip6mr_free_table(net->ipv6.mrt6);

  	net->ipv6.mrt6 = NULL;
  	rtnl_unlock();

  }
  #endif
  
  static struct mr6_table *ip6mr_new_table(struct net *net, u32 id)
  {
  	struct mr6_table *mrt;
  	unsigned int i;
  
  	mrt = ip6mr_get_table(net, id);

  	if (mrt)

  		return mrt;
  
  	mrt = kzalloc(sizeof(*mrt), GFP_KERNEL);

  	if (!mrt)

  		return NULL;
  	mrt->id = id;
  	write_pnet(&mrt->net, net);
  
  	/* Forwarding cache */
  	for (i = 0; i < MFC6_LINES; i++)
  		INIT_LIST_HEAD(&mrt->mfc6_cache_array[i]);
  
  	INIT_LIST_HEAD(&mrt->mfc6_unres_queue);
  
  	setup_timer(&mrt->ipmr_expire_timer, ipmr_expire_process,
  		    (unsigned long)mrt);
  
  #ifdef CONFIG_IPV6_PIMSM_V2
  	mrt->mroute_reg_vif_num = -1;
  #endif
  #ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
  	list_add_tail_rcu(&mrt->list, &net->ipv6.mr6_tables);
  #endif
  	return mrt;
  }

  static void ip6mr_free_table(struct mr6_table *mrt)
  {

  	del_timer_sync(&mrt->ipmr_expire_timer);

  	mroute_clean_tables(mrt, true);

  	kfree(mrt);
  }

  
  #ifdef CONFIG_PROC_FS
  
  struct ipmr_mfc_iter {

  	struct seq_net_private p;

  	struct mr6_table *mrt;

  	struct list_head *cache;

  	int ct;
  };

  static struct mfc6_cache *ipmr_mfc_seq_idx(struct net *net,
  					   struct ipmr_mfc_iter *it, loff_t pos)

  {

  	struct mr6_table *mrt = it->mrt;

  	struct mfc6_cache *mfc;

  	read_lock(&mrt_lock);

  	for (it->ct = 0; it->ct < MFC6_LINES; it->ct++) {

  		it->cache = &mrt->mfc6_cache_array[it->ct];

  		list_for_each_entry(mfc, it->cache, list)

  			if (pos-- == 0)
  				return mfc;

  	}

  	read_unlock(&mrt_lock);

  	spin_lock_bh(&mfc_unres_lock);

  	it->cache = &mrt->mfc6_unres_queue;

  	list_for_each_entry(mfc, it->cache, list)

  		if (pos-- == 0)

  			return mfc;
  	spin_unlock_bh(&mfc_unres_lock);
  
  	it->cache = NULL;
  	return NULL;
  }

  /*
   *	The /proc interfaces to multicast routing /proc/ip6_mr_cache /proc/ip6_mr_vif
   */
  
  struct ipmr_vif_iter {

  	struct seq_net_private p;

  	struct mr6_table *mrt;

  	int ct;
  };

  static struct mif_device *ip6mr_vif_seq_idx(struct net *net,
  					    struct ipmr_vif_iter *iter,

  					    loff_t pos)
  {

  	struct mr6_table *mrt = iter->mrt;

  
  	for (iter->ct = 0; iter->ct < mrt->maxvif; ++iter->ct) {
  		if (!MIF_EXISTS(mrt, iter->ct))

  			continue;
  		if (pos-- == 0)

  			return &mrt->vif6_table[iter->ct];

  	}
  	return NULL;
  }
  
  static void *ip6mr_vif_seq_start(struct seq_file *seq, loff_t *pos)
  	__acquires(mrt_lock)
  {

  	struct ipmr_vif_iter *iter = seq->private;

  	struct net *net = seq_file_net(seq);

  	struct mr6_table *mrt;
  
  	mrt = ip6mr_get_table(net, RT6_TABLE_DFLT);

  	if (!mrt)

  		return ERR_PTR(-ENOENT);
  
  	iter->mrt = mrt;

  	read_lock(&mrt_lock);

  	return *pos ? ip6mr_vif_seq_idx(net, seq->private, *pos - 1)
  		: SEQ_START_TOKEN;

  }
  
  static void *ip6mr_vif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct ipmr_vif_iter *iter = seq->private;

  	struct net *net = seq_file_net(seq);

  	struct mr6_table *mrt = iter->mrt;

  
  	++*pos;
  	if (v == SEQ_START_TOKEN)

  		return ip6mr_vif_seq_idx(net, iter, 0);

  	while (++iter->ct < mrt->maxvif) {
  		if (!MIF_EXISTS(mrt, iter->ct))

  			continue;

  		return &mrt->vif6_table[iter->ct];

  	}
  	return NULL;
  }
  
  static void ip6mr_vif_seq_stop(struct seq_file *seq, void *v)
  	__releases(mrt_lock)
  {
  	read_unlock(&mrt_lock);
  }
  
  static int ip6mr_vif_seq_show(struct seq_file *seq, void *v)
  {

  	struct ipmr_vif_iter *iter = seq->private;
  	struct mr6_table *mrt = iter->mrt;

  	if (v == SEQ_START_TOKEN) {
  		seq_puts(seq,
  			 "Interface      BytesIn  PktsIn  BytesOut PktsOut Flags
  ");
  	} else {
  		const struct mif_device *vif = v;
  		const char *name = vif->dev ? vif->dev->name : "none";
  
  		seq_printf(seq,

  			   "%2td %-10s %8ld %7ld  %8ld %7ld %05X
  ",

  			   vif - mrt->vif6_table,

  			   name, vif->bytes_in, vif->pkt_in,
  			   vif->bytes_out, vif->pkt_out,
  			   vif->flags);
  	}
  	return 0;
  }

  static const struct seq_operations ip6mr_vif_seq_ops = {

  	.start = ip6mr_vif_seq_start,
  	.next  = ip6mr_vif_seq_next,
  	.stop  = ip6mr_vif_seq_stop,
  	.show  = ip6mr_vif_seq_show,
  };
  
  static int ip6mr_vif_open(struct inode *inode, struct file *file)
  {

  	return seq_open_net(inode, file, &ip6mr_vif_seq_ops,
  			    sizeof(struct ipmr_vif_iter));

  }

  static const struct file_operations ip6mr_vif_fops = {

  	.owner	 = THIS_MODULE,
  	.open    = ip6mr_vif_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,

  	.release = seq_release_net,

  };
  
  static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
  {

  	struct ipmr_mfc_iter *it = seq->private;

  	struct net *net = seq_file_net(seq);

  	struct mr6_table *mrt;

  	mrt = ip6mr_get_table(net, RT6_TABLE_DFLT);

  	if (!mrt)

  		return ERR_PTR(-ENOENT);
  
  	it->mrt = mrt;

  	it->cache = NULL;

  	return *pos ? ipmr_mfc_seq_idx(net, seq->private, *pos - 1)
  		: SEQ_START_TOKEN;

  }
  
  static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct mfc6_cache *mfc = v;
  	struct ipmr_mfc_iter *it = seq->private;

  	struct net *net = seq_file_net(seq);

  	struct mr6_table *mrt = it->mrt;

  
  	++*pos;
  
  	if (v == SEQ_START_TOKEN)

  		return ipmr_mfc_seq_idx(net, seq->private, 0);

  	if (mfc->list.next != it->cache)
  		return list_entry(mfc->list.next, struct mfc6_cache, list);

  	if (it->cache == &mrt->mfc6_unres_queue)

  		goto end_of_list;

  	BUG_ON(it->cache != &mrt->mfc6_cache_array[it->ct]);

  	while (++it->ct < MFC6_LINES) {

  		it->cache = &mrt->mfc6_cache_array[it->ct];

  		if (list_empty(it->cache))
  			continue;
  		return list_first_entry(it->cache, struct mfc6_cache, list);

  	}
  
  	/* exhausted cache_array, show unresolved */
  	read_unlock(&mrt_lock);

  	it->cache = &mrt->mfc6_unres_queue;

  	it->ct = 0;
  
  	spin_lock_bh(&mfc_unres_lock);

  	if (!list_empty(it->cache))
  		return list_first_entry(it->cache, struct mfc6_cache, list);

  
   end_of_list:
  	spin_unlock_bh(&mfc_unres_lock);
  	it->cache = NULL;
  
  	return NULL;
  }
  
  static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v)
  {
  	struct ipmr_mfc_iter *it = seq->private;

  	struct mr6_table *mrt = it->mrt;

  	if (it->cache == &mrt->mfc6_unres_queue)

  		spin_unlock_bh(&mfc_unres_lock);

  	else if (it->cache == &mrt->mfc6_cache_array[it->ct])

  		read_unlock(&mrt_lock);
  }
  
  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
  {
  	int n;
  
  	if (v == SEQ_START_TOKEN) {
  		seq_puts(seq,
  			 "Group                            "
  			 "Origin                           "
  			 "Iif      Pkts  Bytes     Wrong  Oifs
  ");
  	} else {
  		const struct mfc6_cache *mfc = v;
  		const struct ipmr_mfc_iter *it = seq->private;

  		struct mr6_table *mrt = it->mrt;

  		seq_printf(seq, "%pI6 %pI6 %-3hd",

  			   &mfc->mf6c_mcastgrp, &mfc->mf6c_origin,

  			   mfc->mf6c_parent);

  		if (it->cache != &mrt->mfc6_unres_queue) {

  			seq_printf(seq, " %8lu %8lu %8lu",
  				   mfc->mfc_un.res.pkt,
  				   mfc->mfc_un.res.bytes,
  				   mfc->mfc_un.res.wrong_if);

  			for (n = mfc->mfc_un.res.minvif;
  			     n < mfc->mfc_un.res.maxvif; n++) {

  				if (MIF_EXISTS(mrt, n) &&

  				    mfc->mfc_un.res.ttls[n] < 255)
  					seq_printf(seq,
  						   " %2d:%-3d",
  						   n, mfc->mfc_un.res.ttls[n]);
  			}

  		} else {
  			/* unresolved mfc_caches don't contain
  			 * pkt, bytes and wrong_if values
  			 */
  			seq_printf(seq, " %8lu %8lu %8lu", 0ul, 0ul, 0ul);

  		}
  		seq_putc(seq, '
  ');
  	}
  	return 0;
  }

  static const struct seq_operations ipmr_mfc_seq_ops = {

  	.start = ipmr_mfc_seq_start,
  	.next  = ipmr_mfc_seq_next,
  	.stop  = ipmr_mfc_seq_stop,
  	.show  = ipmr_mfc_seq_show,
  };
  
  static int ipmr_mfc_open(struct inode *inode, struct file *file)
  {

  	return seq_open_net(inode, file, &ipmr_mfc_seq_ops,
  			    sizeof(struct ipmr_mfc_iter));

  }

  static const struct file_operations ip6mr_mfc_fops = {

  	.owner	 = THIS_MODULE,
  	.open    = ipmr_mfc_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,

  	.release = seq_release_net,

  };
  #endif

  #ifdef CONFIG_IPV6_PIMSM_V2

  
  static int pim6_rcv(struct sk_buff *skb)
  {
  	struct pimreghdr *pim;
  	struct ipv6hdr   *encap;
  	struct net_device  *reg_dev = NULL;

  	struct net *net = dev_net(skb->dev);

  	struct mr6_table *mrt;

  	struct flowi6 fl6 = {
  		.flowi6_iif	= skb->dev->ifindex,
  		.flowi6_mark	= skb->mark,

  	};
  	int reg_vif_num;

  
  	if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(*encap)))
  		goto drop;
  
  	pim = (struct pimreghdr *)skb_transport_header(skb);

  	if (pim->type != ((PIM_VERSION << 4) | PIM_TYPE_REGISTER) ||

  	    (pim->flags & PIM_NULL_REGISTER) ||

  	    (csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
  			     sizeof(*pim), IPPROTO_PIM,
  			     csum_partial((void *)pim, sizeof(*pim), 0)) &&

  	     csum_fold(skb_checksum(skb, 0, skb->len, 0))))

  		goto drop;
  
  	/* check if the inner packet is destined to mcast group */
  	encap = (struct ipv6hdr *)(skb_transport_header(skb) +
  				   sizeof(*pim));
  
  	if (!ipv6_addr_is_multicast(&encap->daddr) ||
  	    encap->payload_len == 0 ||
  	    ntohs(encap->payload_len) + sizeof(*pim) > skb->len)
  		goto drop;

  	if (ip6mr_fib_lookup(net, &fl6, &mrt) < 0)

  		goto drop;
  	reg_vif_num = mrt->mroute_reg_vif_num;

  	read_lock(&mrt_lock);
  	if (reg_vif_num >= 0)

  		reg_dev = mrt->vif6_table[reg_vif_num].dev;

  	if (reg_dev)
  		dev_hold(reg_dev);
  	read_unlock(&mrt_lock);

  	if (!reg_dev)

  		goto drop;
  
  	skb->mac_header = skb->network_header;
  	skb_pull(skb, (u8 *)encap - skb->data);
  	skb_reset_network_header(skb);

  	skb->protocol = htons(ETH_P_IPV6);

  	skb->ip_summed = CHECKSUM_NONE;

  	skb_tunnel_rx(skb, reg_dev, dev_net(reg_dev));

  	netif_rx(skb);

  	dev_put(reg_dev);
  	return 0;
   drop:
  	kfree_skb(skb);
  	return 0;
  }

  static const struct inet6_protocol pim6_protocol = {

  	.handler	=	pim6_rcv,
  };
  
  /* Service routines creating virtual interfaces: PIMREG */

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

  {

  	struct net *net = dev_net(dev);

  	struct mr6_table *mrt;

  	struct flowi6 fl6 = {
  		.flowi6_oif	= dev->ifindex,

  		.flowi6_iif	= skb->skb_iif ? : LOOPBACK_IFINDEX,

  		.flowi6_mark	= skb->mark,

  	};
  	int err;

  	err = ip6mr_fib_lookup(net, &fl6, &mrt);

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

  		return err;

  	}

  	read_lock(&mrt_lock);

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

  	ip6mr_cache_report(mrt, skb, mrt->mroute_reg_vif_num, MRT6MSG_WHOLEPKT);

  	read_unlock(&mrt_lock);
  	kfree_skb(skb);

  	return NETDEV_TX_OK;

  }

  static int reg_vif_get_iflink(const struct net_device *dev)
  {
  	return 0;
  }

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

  	.ndo_get_iflink = reg_vif_get_iflink,

  };

  static void reg_vif_setup(struct net_device *dev)
  {
  	dev->type		= ARPHRD_PIMREG;
  	dev->mtu		= 1500 - sizeof(struct ipv6hdr) - 8;
  	dev->flags		= IFF_NOARP;

  	dev->netdev_ops		= &reg_vif_netdev_ops;

  	dev->needs_free_netdev	= true;

  	dev->features		|= NETIF_F_NETNS_LOCAL;

  }

  static struct net_device *ip6mr_reg_vif(struct net *net, struct mr6_table *mrt)

  {
  	struct net_device *dev;

  	char name[IFNAMSIZ];
  
  	if (mrt->id == RT6_TABLE_DFLT)
  		sprintf(name, "pim6reg");
  	else
  		sprintf(name, "pim6reg%u", mrt->id);

  	dev = alloc_netdev(0, name, NET_NAME_UNKNOWN, reg_vif_setup);

  	if (!dev)

  		return NULL;

  	dev_net_set(dev, net);

  	if (register_netdevice(dev)) {
  		free_netdev(dev);
  		return NULL;
  	}

  	if (dev_open(dev))
  		goto failure;

  	dev_hold(dev);

  	return dev;
  
  failure:

  	unregister_netdevice(dev);
  	return NULL;
  }
  #endif

  /*
   *	Delete a VIF entry
   */

  static int mif6_delete(struct mr6_table *mrt, int vifi, int notify,
  		       struct list_head *head)

  {
  	struct mif_device *v;
  	struct net_device *dev;

  	struct inet6_dev *in6_dev;

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

  		return -EADDRNOTAVAIL;

  	v = &mrt->vif6_table[vifi];

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

  #ifdef CONFIG_IPV6_PIMSM_V2

  	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 (MIF_EXISTS(mrt, tmp))

  				break;
  		}

  		mrt->maxvif = tmp + 1;

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

  	in6_dev = __in6_dev_get(dev);

  	if (in6_dev) {

  		in6_dev->cnf.mc_forwarding--;

  		inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,

  					     NETCONFA_MC_FORWARDING,
  					     dev->ifindex, &in6_dev->cnf);
  	}

  	if ((v->flags & MIFF_REGISTER) && !notify)

  		unregister_netdevice_queue(dev, head);

  
  	dev_put(dev);
  	return 0;
  }

  static inline void ip6mr_cache_free(struct mfc6_cache *c)
  {

  	kmem_cache_free(mrt_cachep, c);
  }

  /* Destroy an unresolved cache entry, killing queued skbs
     and reporting error to netlink readers.
   */

  static void ip6mr_destroy_unres(struct mr6_table *mrt, struct mfc6_cache *c)

  {

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

  	struct sk_buff *skb;

  	atomic_dec(&mrt->cache_resolve_queue_len);

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

  		if (ipv6_hdr(skb)->version == 0) {

  			struct nlmsghdr *nlh = skb_pull(skb,
  							sizeof(struct ipv6hdr));

  			nlh->nlmsg_type = NLMSG_ERROR;

  			nlh->nlmsg_len = nlmsg_msg_size(sizeof(struct nlmsgerr));

  			skb_trim(skb, nlh->nlmsg_len);

  			((struct nlmsgerr *)nlmsg_data(nlh))->error = -ETIMEDOUT;

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

  		} else
  			kfree_skb(skb);
  	}

  	ip6mr_cache_free(c);

  }

  /* Timer process for all the unresolved queue. */

  static void ipmr_do_expire_process(struct mr6_table *mrt)

  {
  	unsigned long now = jiffies;
  	unsigned long expires = 10 * HZ;

  	struct mfc6_cache *c, *next;

  	list_for_each_entry_safe(c, next, &mrt->mfc6_unres_queue, list) {

  		if (time_after(c->mfc_un.unres.expires, now)) {
  			/* not yet... */
  			unsigned long interval = c->mfc_un.unres.expires - now;
  			if (interval < expires)
  				expires = interval;

  			continue;
  		}

  		list_del(&c->list);

  		mr6_netlink_event(mrt, c, RTM_DELROUTE);

  		ip6mr_destroy_unres(mrt, c);

  	}

  	if (!list_empty(&mrt->mfc6_unres_queue))
  		mod_timer(&mrt->ipmr_expire_timer, jiffies + expires);

  }

  static void ipmr_expire_process(unsigned long arg)

  {

  	struct mr6_table *mrt = (struct mr6_table *)arg;

  	if (!spin_trylock(&mfc_unres_lock)) {

  		mod_timer(&mrt->ipmr_expire_timer, jiffies + 1);

  		return;
  	}

  	if (!list_empty(&mrt->mfc6_unres_queue))
  		ipmr_do_expire_process(mrt);

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

  static void ip6mr_update_thresholds(struct mr6_table *mrt, struct mfc6_cache *cache,

  				    unsigned char *ttls)

  {
  	int vifi;

  	cache->mfc_un.res.minvif = MAXMIFS;

  	cache->mfc_un.res.maxvif = 0;

  	memset(cache->mfc_un.res.ttls, 255, MAXMIFS);

  	for (vifi = 0; vifi < mrt->maxvif; vifi++) {
  		if (MIF_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;
  		}
  	}

  	cache->mfc_un.res.lastuse = jiffies;

  }

  static int mif6_add(struct net *net, struct mr6_table *mrt,
  		    struct mif6ctl *vifc, int mrtsock)

  {
  	int vifi = vifc->mif6c_mifi;

  	struct mif_device *v = &mrt->vif6_table[vifi];

  	struct net_device *dev;

  	struct inet6_dev *in6_dev;

  	int err;

  
  	/* Is vif busy ? */

  	if (MIF_EXISTS(mrt, vifi))

  		return -EADDRINUSE;
  
  	switch (vifc->mif6c_flags) {

  #ifdef CONFIG_IPV6_PIMSM_V2
  	case MIFF_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 = ip6mr_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 0:

  		dev = dev_get_by_index(net, vifc->mif6c_pifi);

  		if (!dev)
  			return -EADDRNOTAVAIL;

  		err = dev_set_allmulti(dev, 1);

  		if (err) {
  			dev_put(dev);

  			return err;

  		}

  		break;
  	default:
  		return -EINVAL;
  	}

  	in6_dev = __in6_dev_get(dev);

  	if (in6_dev) {

  		in6_dev->cnf.mc_forwarding++;

  		inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,

  					     NETCONFA_MC_FORWARDING,
  					     dev->ifindex, &in6_dev->cnf);
  	}

  	/*
  	 *	Fill in the VIF structures
  	 */
  	v->rate_limit = vifc->vifc_rate_limit;
  	v->flags = vifc->mif6c_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 & MIFF_REGISTER)

  		v->link = dev_get_iflink(dev);

  
  	/* And finish update writing critical data */
  	write_lock_bh(&mrt_lock);

  	v->dev = dev;

  #ifdef CONFIG_IPV6_PIMSM_V2
  	if (v->flags & MIFF_REGISTER)

  		mrt->mroute_reg_vif_num = vifi;

  #endif

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

  	write_unlock_bh(&mrt_lock);
  	return 0;
  }

  static struct mfc6_cache *ip6mr_cache_find(struct mr6_table *mrt,

  					   const struct in6_addr *origin,
  					   const struct in6_addr *mcastgrp)

  {
  	int line = MFC6_HASH(mcastgrp, origin);
  	struct mfc6_cache *c;

  	list_for_each_entry(c, &mrt->mfc6_cache_array[line], list) {

  		if (ipv6_addr_equal(&c->mf6c_origin, origin) &&
  		    ipv6_addr_equal(&c->mf6c_mcastgrp, mcastgrp))

  			return c;

  	}

  	return NULL;

  }

  /* Look for a (*,*,oif) entry */
  static struct mfc6_cache *ip6mr_cache_find_any_parent(struct mr6_table *mrt,
  						      mifi_t mifi)
  {
  	int line = MFC6_HASH(&in6addr_any, &in6addr_any);
  	struct mfc6_cache *c;
  
  	list_for_each_entry(c, &mrt->mfc6_cache_array[line], list)
  		if (ipv6_addr_any(&c->mf6c_origin) &&
  		    ipv6_addr_any(&c->mf6c_mcastgrp) &&
  		    (c->mfc_un.res.ttls[mifi] < 255))
  			return c;
  
  	return NULL;
  }
  
  /* Look for a (*,G) entry */
  static struct mfc6_cache *ip6mr_cache_find_any(struct mr6_table *mrt,
  					       struct in6_addr *mcastgrp,
  					       mifi_t mifi)
  {
  	int line = MFC6_HASH(mcastgrp, &in6addr_any);
  	struct mfc6_cache *c, *proxy;
  
  	if (ipv6_addr_any(mcastgrp))
  		goto skip;
  
  	list_for_each_entry(c, &mrt->mfc6_cache_array[line], list)
  		if (ipv6_addr_any(&c->mf6c_origin) &&
  		    ipv6_addr_equal(&c->mf6c_mcastgrp, mcastgrp)) {
  			if (c->mfc_un.res.ttls[mifi] < 255)
  				return c;
  
  			/* It's ok if the mifi is part of the static tree */
  			proxy = ip6mr_cache_find_any_parent(mrt,
  							    c->mf6c_parent);
  			if (proxy && proxy->mfc_un.res.ttls[mifi] < 255)
  				return c;
  		}
  
  skip:
  	return ip6mr_cache_find_any_parent(mrt, mifi);
  }

  /*
   *	Allocate a multicast cache entry
   */

  static struct mfc6_cache *ip6mr_cache_alloc(void)

  {

  	struct mfc6_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_KERNEL);

  	if (!c)

  		return NULL;

  	c->mfc_un.res.last_assert = jiffies - MFC_ASSERT_THRESH - 1;

  	c->mfc_un.res.minvif = MAXMIFS;

  	return c;
  }

  static struct mfc6_cache *ip6mr_cache_alloc_unres(void)

  {

  	struct mfc6_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_ATOMIC);

  	if (!c)

  		return NULL;

  	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 ip6mr_cache_resolve(struct net *net, struct mr6_table *mrt,
  				struct mfc6_cache *uc, struct mfc6_cache *c)

  {
  	struct sk_buff *skb;
  
  	/*
  	 *	Play the pending entries through our router
  	 */

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

  		if (ipv6_hdr(skb)->version == 0) {

  			struct nlmsghdr *nlh = skb_pull(skb,
  							sizeof(struct ipv6hdr));

  			if (__ip6mr_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_msg_size(sizeof(struct nlmsgerr));

  				skb_trim(skb, nlh->nlmsg_len);

  				((struct nlmsgerr *)nlmsg_data(nlh))->error = -EMSGSIZE;

  			}

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

  		} else

  			ip6_mr_forward(net, mrt, skb, c);

  	}
  }
  
  /*

   *	Bounce a cache query up to pim6sd and netlink.

   *
   *	Called under mrt_lock.
   */

  static int ip6mr_cache_report(struct mr6_table *mrt, struct sk_buff *pkt,
  			      mifi_t mifi, int assert)

  {
  	struct sk_buff *skb;
  	struct mrt6msg *msg;
  	int ret;

  #ifdef CONFIG_IPV6_PIMSM_V2
  	if (assert == MRT6MSG_WHOLEPKT)
  		skb = skb_realloc_headroom(pkt, -skb_network_offset(pkt)
  						+sizeof(*msg));
  	else
  #endif
  		skb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(*msg), GFP_ATOMIC);

  
  	if (!skb)
  		return -ENOBUFS;
  
  	/* I suppose that internal messages
  	 * do not require checksums */
  
  	skb->ip_summed = CHECKSUM_UNNECESSARY;

  #ifdef CONFIG_IPV6_PIMSM_V2
  	if (assert == MRT6MSG_WHOLEPKT) {
  		/* Ugly, but we have no choice with this interface.
  		   Duplicate old header, fix length etc.
  		   And all this only to mangle msg->im6_msgtype and
  		   to set msg->im6_mbz to "mbz" :-)
  		 */
  		skb_push(skb, -skb_network_offset(pkt));
  
  		skb_push(skb, sizeof(*msg));
  		skb_reset_transport_header(skb);
  		msg = (struct mrt6msg *)skb_transport_header(skb);
  		msg->im6_mbz = 0;
  		msg->im6_msgtype = MRT6MSG_WHOLEPKT;

  		msg->im6_mif = mrt->mroute_reg_vif_num;

  		msg->im6_pad = 0;

  		msg->im6_src = ipv6_hdr(pkt)->saddr;
  		msg->im6_dst = ipv6_hdr(pkt)->daddr;

  
  		skb->ip_summed = CHECKSUM_UNNECESSARY;
  	} else
  #endif
  	{

  	/*
  	 *	Copy the IP header
  	 */
  
  	skb_put(skb, sizeof(struct ipv6hdr));
  	skb_reset_network_header(skb);
  	skb_copy_to_linear_data(skb, ipv6_hdr(pkt), sizeof(struct ipv6hdr));
  
  	/*
  	 *	Add our header
  	 */
  	skb_put(skb, sizeof(*msg));
  	skb_reset_transport_header(skb);
  	msg = (struct mrt6msg *)skb_transport_header(skb);
  
  	msg->im6_mbz = 0;
  	msg->im6_msgtype = assert;

  	msg->im6_mif = mifi;

  	msg->im6_pad = 0;

  	msg->im6_src = ipv6_hdr(pkt)->saddr;
  	msg->im6_dst = ipv6_hdr(pkt)->daddr;

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

  	skb->ip_summed = CHECKSUM_UNNECESSARY;

  	}

  	if (!mrt->mroute6_sk) {

  		kfree_skb(skb);
  		return -EINVAL;
  	}

  	mrt6msg_netlink_event(mrt, skb);

  	/*
  	 *	Deliver to user space multicast routing algorithms
  	 */

  	ret = sock_queue_rcv_skb(mrt->mroute6_sk, skb);

  	if (ret < 0) {

  		net_warn_ratelimited("mroute6: pending queue full, dropping entries
  ");

  		kfree_skb(skb);
  	}
  
  	return ret;
  }
  
  /*
   *	Queue a packet for resolution. It gets locked cache entry!
   */
  
  static int

  ip6mr_cache_unresolved(struct mr6_table *mrt, mifi_t mifi, struct sk_buff *skb)

  {

  	bool found = false;

  	int err;
  	struct mfc6_cache *c;
  
  	spin_lock_bh(&mfc_unres_lock);

  	list_for_each_entry(c, &mrt->mfc6_unres_queue, list) {

  		if (ipv6_addr_equal(&c->mf6c_mcastgrp, &ipv6_hdr(skb)->daddr) &&

  		    ipv6_addr_equal(&c->mf6c_origin, &ipv6_hdr(skb)->saddr)) {
  			found = true;

  			break;

  		}

  	}

  	if (!found) {

  		/*
  		 *	Create a new entry if allowable
  		 */

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

  		    (c = ip6mr_cache_alloc_unres()) == NULL) {

  			spin_unlock_bh(&mfc_unres_lock);
  
  			kfree_skb(skb);
  			return -ENOBUFS;
  		}
  
  		/*
  		 *	Fill in the new cache entry
  		 */
  		c->mf6c_parent = -1;
  		c->mf6c_origin = ipv6_hdr(skb)->saddr;
  		c->mf6c_mcastgrp = ipv6_hdr(skb)->daddr;
  
  		/*
  		 *	Reflect first query at pim6sd
  		 */

  		err = ip6mr_cache_report(mrt, skb, mifi, MRT6MSG_NOCACHE);

  		if (err < 0) {

  			/* If the report failed throw the cache entry
  			   out - Brad Parker
  			 */
  			spin_unlock_bh(&mfc_unres_lock);

  			ip6mr_cache_free(c);

  			kfree_skb(skb);
  			return err;
  		}

  		atomic_inc(&mrt->cache_resolve_queue_len);
  		list_add(&c->list, &mrt->mfc6_unres_queue);

  		mr6_netlink_event(mrt, c, RTM_NEWROUTE);

  		ipmr_do_expire_process(mrt);

  	}
  
  	/*
  	 *	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;
  }
  
  /*
   *	MFC6 cache manipulation by user space
   */

  static int ip6mr_mfc_delete(struct mr6_table *mrt, struct mf6cctl *mfc,
  			    int parent)

  {
  	int line;

  	struct mfc6_cache *c, *next;

  
  	line = MFC6_HASH(&mfc->mf6cc_mcastgrp.sin6_addr, &mfc->mf6cc_origin.sin6_addr);

  	list_for_each_entry_safe(c, next, &mrt->mfc6_cache_array[line], list) {

  		if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&

  		    ipv6_addr_equal(&c->mf6c_mcastgrp,
  				    &mfc->mf6cc_mcastgrp.sin6_addr) &&
  		    (parent == -1 || parent == c->mf6c_parent)) {

  			write_lock_bh(&mrt_lock);

  			list_del(&c->list);

  			write_unlock_bh(&mrt_lock);

  			mr6_netlink_event(mrt, c, RTM_DELROUTE);

  			ip6mr_cache_free(c);

  			return 0;
  		}
  	}
  	return -ENOENT;
  }
  
  static int ip6mr_device_event(struct notifier_block *this,
  			      unsigned long event, void *ptr)
  {

  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

  	struct net *net = dev_net(dev);

  	struct mr6_table *mrt;

  	struct mif_device *v;
  	int ct;

  	if (event != NETDEV_UNREGISTER)
  		return NOTIFY_DONE;

  	ip6mr_for_each_table(mrt, net) {
  		v = &mrt->vif6_table[0];
  		for (ct = 0; ct < mrt->maxvif; ct++, v++) {
  			if (v->dev == dev)

  				mif6_delete(mrt, ct, 1, NULL);

  		}

  	}

  	return NOTIFY_DONE;
  }
  
  static struct notifier_block ip6_mr_notifier = {
  	.notifier_call = ip6mr_device_event
  };
  
  /*
   *	Setup for IP multicast routing
   */

  static int __net_init ip6mr_net_init(struct net *net)
  {

  	int err;

  	err = ip6mr_rules_init(net);
  	if (err < 0)

  		goto fail;

  
  #ifdef CONFIG_PROC_FS
  	err = -ENOMEM;

  	if (!proc_create("ip6_mr_vif", 0, net->proc_net, &ip6mr_vif_fops))

  		goto proc_vif_fail;

  	if (!proc_create("ip6_mr_cache", 0, net->proc_net, &ip6mr_mfc_fops))

  		goto proc_cache_fail;
  #endif

  	return 0;

  #ifdef CONFIG_PROC_FS
  proc_cache_fail:

  	remove_proc_entry("ip6_mr_vif", net->proc_net);

  proc_vif_fail:

  	ip6mr_rules_exit(net);

  #endif

  fail:
  	return err;
  }
  
  static void __net_exit ip6mr_net_exit(struct net *net)
  {

  #ifdef CONFIG_PROC_FS

  	remove_proc_entry("ip6_mr_cache", net->proc_net);
  	remove_proc_entry("ip6_mr_vif", net->proc_net);

  #endif

  	ip6mr_rules_exit(net);

  }
  
  static struct pernet_operations ip6mr_net_ops = {
  	.init = ip6mr_net_init,
  	.exit = ip6mr_net_exit,
  };

  int __init ip6_mr_init(void)

  {

  	int err;

  	mrt_cachep = kmem_cache_create("ip6_mrt_cache",
  				       sizeof(struct mfc6_cache),
  				       0, SLAB_HWCACHE_ALIGN,
  				       NULL);
  	if (!mrt_cachep)

  		return -ENOMEM;

  	err = register_pernet_subsys(&ip6mr_net_ops);
  	if (err)
  		goto reg_pernet_fail;

  	err = register_netdevice_notifier(&ip6_mr_notifier);
  	if (err)
  		goto reg_notif_fail;

  #ifdef CONFIG_IPV6_PIMSM_V2
  	if (inet6_add_protocol(&pim6_protocol, IPPROTO_PIM) < 0) {

  		pr_err("%s: can't add PIM protocol
  ", __func__);

  		err = -EAGAIN;
  		goto add_proto_fail;
  	}
  #endif

  	rtnl_register(RTNL_FAMILY_IP6MR, RTM_GETROUTE, NULL,

  		      ip6mr_rtm_dumproute, 0);

  	return 0;

  #ifdef CONFIG_IPV6_PIMSM_V2
  add_proto_fail:
  	unregister_netdevice_notifier(&ip6_mr_notifier);
  #endif

  reg_notif_fail:

  	unregister_pernet_subsys(&ip6mr_net_ops);
  reg_pernet_fail:

  	kmem_cache_destroy(mrt_cachep);

  	return err;

  }

  void ip6_mr_cleanup(void)
  {

  	rtnl_unregister(RTNL_FAMILY_IP6MR, RTM_GETROUTE);
  #ifdef CONFIG_IPV6_PIMSM_V2
  	inet6_del_protocol(&pim6_protocol, IPPROTO_PIM);
  #endif

  	unregister_netdevice_notifier(&ip6_mr_notifier);

  	unregister_pernet_subsys(&ip6mr_net_ops);

  	kmem_cache_destroy(mrt_cachep);
  }

  static int ip6mr_mfc_add(struct net *net, struct mr6_table *mrt,

  			 struct mf6cctl *mfc, int mrtsock, int parent)

  {

  	bool found = false;

  	int line;

  	struct mfc6_cache *uc, *c;

  	unsigned char ttls[MAXMIFS];

  	int i;

  	if (mfc->mf6cc_parent >= MAXMIFS)
  		return -ENFILE;

  	memset(ttls, 255, MAXMIFS);
  	for (i = 0; i < MAXMIFS; i++) {

  		if (IF_ISSET(i, &mfc->mf6cc_ifset))
  			ttls[i] = 1;
  
  	}
  
  	line = MFC6_HASH(&mfc->mf6cc_mcastgrp.sin6_addr, &mfc->mf6cc_origin.sin6_addr);

  	list_for_each_entry(c, &mrt->mfc6_cache_array[line], list) {

  		if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&

  		    ipv6_addr_equal(&c->mf6c_mcastgrp,
  				    &mfc->mf6cc_mcastgrp.sin6_addr) &&
  		    (parent == -1 || parent == mfc->mf6cc_parent)) {

  			found = true;

  			break;

  		}

  	}

  	if (found) {

  		write_lock_bh(&mrt_lock);
  		c->mf6c_parent = mfc->mf6cc_parent;

  		ip6mr_update_thresholds(mrt, c, ttls);

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

  		mr6_netlink_event(mrt, c, RTM_NEWROUTE);

  		return 0;
  	}

  	if (!ipv6_addr_any(&mfc->mf6cc_mcastgrp.sin6_addr) &&
  	    !ipv6_addr_is_multicast(&mfc->mf6cc_mcastgrp.sin6_addr))

  		return -EINVAL;

  	c = ip6mr_cache_alloc();

  	if (!c)

  		return -ENOMEM;
  
  	c->mf6c_origin = mfc->mf6cc_origin.sin6_addr;
  	c->mf6c_mcastgrp = mfc->mf6cc_mcastgrp.sin6_addr;
  	c->mf6c_parent = mfc->mf6cc_parent;

  	ip6mr_update_thresholds(mrt, c, ttls);

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

  	list_add(&c->list, &mrt->mfc6_cache_array[line]);

  	write_unlock_bh(&mrt_lock);
  
  	/*
  	 *	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->mfc6_unres_queue, list) {

  		if (ipv6_addr_equal(&uc->mf6c_origin, &c->mf6c_origin) &&

  		    ipv6_addr_equal(&uc->mf6c_mcastgrp, &c->mf6c_mcastgrp)) {

  			list_del(&uc->list);

  			atomic_dec(&mrt->cache_resolve_queue_len);

  			found = true;

  			break;
  		}
  	}

  	if (list_empty(&mrt->mfc6_unres_queue))
  		del_timer(&mrt->ipmr_expire_timer);

  	spin_unlock_bh(&mfc_unres_lock);

  	if (found) {

  		ip6mr_cache_resolve(net, mrt, uc, c);

  		ip6mr_cache_free(uc);

  	}

  	mr6_netlink_event(mrt, c, RTM_NEWROUTE);

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

  static void mroute_clean_tables(struct mr6_table *mrt, bool all)

  {
  	int i;

  	LIST_HEAD(list);

  	struct mfc6_cache *c, *next;

  
  	/*
  	 *	Shut down all active vif entries
  	 */

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

  		if (!all && (mrt->vif6_table[i].flags & VIFF_STATIC))
  			continue;

  		mif6_delete(mrt, i, 0, &list);

  	}

  	unregister_netdevice_many(&list);

  
  	/*
  	 *	Wipe the cache
  	 */

  	for (i = 0; i < MFC6_LINES; i++) {

  		list_for_each_entry_safe(c, next, &mrt->mfc6_cache_array[i], list) {

  			if (!all && (c->mfc_flags & MFC_STATIC))

  				continue;

  			write_lock_bh(&mrt_lock);

  			list_del(&c->list);

  			write_unlock_bh(&mrt_lock);

  			mr6_netlink_event(mrt, c, RTM_DELROUTE);

  			ip6mr_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->mfc6_unres_queue, list) {

  			list_del(&c->list);

  			mr6_netlink_event(mrt, c, RTM_DELROUTE);

  			ip6mr_destroy_unres(mrt, c);

  		}
  		spin_unlock_bh(&mfc_unres_lock);
  	}
  }

  static int ip6mr_sk_init(struct mr6_table *mrt, struct sock *sk)

  {
  	int err = 0;

  	struct net *net = sock_net(sk);

  
  	rtnl_lock();
  	write_lock_bh(&mrt_lock);

  	if (likely(mrt->mroute6_sk == NULL)) {
  		mrt->mroute6_sk = sk;

  		net->ipv6.devconf_all->mc_forwarding++;

  	} else {

  		err = -EADDRINUSE;

  	}

  	write_unlock_bh(&mrt_lock);

  	if (!err)

  		inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
  					     NETCONFA_MC_FORWARDING,

  					     NETCONFA_IFINDEX_ALL,
  					     net->ipv6.devconf_all);

  	rtnl_unlock();
  
  	return err;
  }
  
  int ip6mr_sk_done(struct sock *sk)
  {

  	int err = -EACCES;

  	struct net *net = sock_net(sk);

  	struct mr6_table *mrt;

  
  	rtnl_lock();

  	ip6mr_for_each_table(mrt, net) {
  		if (sk == mrt->mroute6_sk) {
  			write_lock_bh(&mrt_lock);
  			mrt->mroute6_sk = NULL;
  			net->ipv6.devconf_all->mc_forwarding--;

  			write_unlock_bh(&mrt_lock);