text: /*
   *	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/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/ip_tunnels.h>
  #include <net/checksum.h>
  #include <net/netlink.h>
  #include <net/fib_rules.h>
  #include <linux/netconf.h>
  #include <net/nexthop.h>
  
  #include <linux/nospec.h>
  
  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 */
  
  /* 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 void ipmr_free_table(struct mr_table *mrt);
  
  static void 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 mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,
  				 int cmd);
  static void mroute_clean_tables(struct mr_table *mrt, bool all);
  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)
  {
  	int err;
  	struct ipmr_result res;
  	struct fib_lookup_arg arg = {
  		.result = &res,
  		.flags = FIB_LOOKUP_NOREF,
  	};
  
  	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)
  		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_initconst 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,
  	.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 (IS_ERR(mrt)) {
  		err = PTR_ERR(mrt);
  		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:
  	ipmr_free_table(mrt);
  err1:
  	fib_rules_unregister(ops);
  	return err;
  }
  
  static void __net_exit ipmr_rules_exit(struct net *net)
  {
  	struct mr_table *mrt, *next;
  
  	rtnl_lock();
  	list_for_each_entry_safe(mrt, next, &net->ipv4.mr_tables, list) {
  		list_del(&mrt->list);
  		ipmr_free_table(mrt);
  	}
  	fib_rules_unregister(net->ipv4.mr_rules_ops);
  	rtnl_unlock();
  }
  #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)
  {
  	struct mr_table *mrt;
  
  	mrt = ipmr_new_table(net, RT_TABLE_DEFAULT);
  	if (IS_ERR(mrt))
  		return PTR_ERR(mrt);
  	net->ipv4.mrt = mrt;
  	return 0;
  }
  
  static void __net_exit ipmr_rules_exit(struct net *net)
  {
  	rtnl_lock();
  	ipmr_free_table(net->ipv4.mrt);
  	net->ipv4.mrt = NULL;
  	rtnl_unlock();
  }
  #endif
  
  static struct mr_table *ipmr_new_table(struct net *net, u32 id)
  {
  	struct mr_table *mrt;
  	unsigned int i;
  
  	/* "pimreg%u" should not exceed 16 bytes (IFNAMSIZ) */
  	if (id != RT_TABLE_DEFAULT && id >= 1000000000)
  		return ERR_PTR(-EINVAL);
  
  	mrt = ipmr_get_table(net, id);
  	if (mrt)
  		return mrt;
  
  	mrt = kzalloc(sizeof(*mrt), GFP_KERNEL);
  	if (!mrt)
  		return ERR_PTR(-ENOMEM);
  	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);
  
  	mrt->mroute_reg_vif_num = -1;
  #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
  	list_add_tail_rcu(&mrt->list, &net->ipv4.mr_tables);
  #endif
  	return mrt;
  }
  
  static void ipmr_free_table(struct mr_table *mrt)
  {
  	del_timer_sync(&mrt->ipmr_expire_timer);
  	mroute_clean_tables(mrt, true);
  	kfree(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);
  		}
  	}
  }
  
  /* Initialize ipmr pimreg/tunnel in_device */
  static bool ipmr_init_vif_indev(const struct net_device *dev)
  {
  	struct in_device *in_dev;
  
  	ASSERT_RTNL();
  
  	in_dev = __in_dev_get_rtnl(dev);
  	if (!in_dev)
  		return false;
  	ipv4_devconf_setall(in_dev);
  	neigh_parms_data_state_setall(in_dev->arp_parms);
  	IPV4_DEVCONF(in_dev->cnf, RP_FILTER) = 0;
  
  	return true;
  }
  
  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;
  
  		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;
  			if (!ipmr_init_vif_indev(dev))
  				goto failure;
  			if (dev_open(dev))
  				goto failure;
  			dev_hold(dev);
  		}
  	}
  	return dev;
  
  failure:
  	unregister_netdevice(dev);
  	return NULL;
  }
  
  #if defined(CONFIG_IP_PIMSM_V1) || defined(CONFIG_IP_PIMSM_V2)
  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 ? : LOOPBACK_IFINDEX,
  		.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 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		= 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;
  	char name[IFNAMSIZ];
  
  	if (mrt->id == RT_TABLE_DEFAULT)
  		sprintf(name, "pimreg");
  	else
  		sprintf(name, "pimreg%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 (!ipmr_init_vif_indev(dev))
  		goto failure;
  	if (dev_open(dev))
  		goto failure;
  
  	dev_hold(dev);
  
  	return dev;
  
  failure:
  	unregister_netdevice(dev);
  	return NULL;
  }
  
  /* called with rcu_read_lock() */
  static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb,
  		     unsigned int pimlen)
  {
  	struct net_device *reg_dev = NULL;
  	struct iphdr *encap;
  
  	encap = (struct iphdr *)(skb_transport_header(skb) + pimlen);
  	/* Check that:
  	 * a. packet is really sent to a multicast group
  	 * b. packet is not a NULL-REGISTER
  	 * c. packet is not truncated
  	 */
  	if (!ipv4_is_multicast(encap->daddr) ||
  	    encap->tot_len == 0 ||
  	    ntohs(encap->tot_len) + pimlen > skb->len)
  		return 1;
  
  	read_lock(&mrt_lock);
  	if (mrt->mroute_reg_vif_num >= 0)
  		reg_dev = mrt->vif_table[mrt->mroute_reg_vif_num].dev;
  	read_unlock(&mrt_lock);
  
  	if (!reg_dev)
  		return 1;
  
  	skb->mac_header = skb->network_header;
  	skb_pull(skb, (u8 *)encap - skb->data);
  	skb_reset_network_header(skb);
  	skb->protocol = htons(ETH_P_IP);
  	skb->ip_summed = CHECKSUM_NONE;
  
  	skb_tunnel_rx(skb, reg_dev, dev_net(reg_dev));
  
  	netif_rx(skb);
  
  	return NET_RX_SUCCESS;
  }
  #else
  static struct net_device *ipmr_reg_vif(struct net *net, struct mr_table *mrt)
  {
  	return NULL;
  }
  #endif
  
  /**
   *	vif_delete - 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;
  	}
  
  	if (vifi == mrt->mroute_reg_vif_num)
  		mrt->mroute_reg_vif_num = -1;
  
  	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)--;
  		inet_netconf_notify_devconf(dev_net(dev),
  					    NETCONFA_MC_FORWARDING,
  					    dev->ifindex, &in_dev->cnf);
  		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_msg_size(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).portid);
  		} 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);
  		mroute_netlink_event(mrt, c, RTM_DELROUTE);
  		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;
  		}
  	}
  	cache->mfc_un.res.lastuse = jiffies;
  }
  
  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) {
  	case VIFF_REGISTER:
  		if (!ipmr_pimsm_enabled())
  			return -EINVAL;
  		/* 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;
  	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)) {
  				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)++;
  	inet_netconf_notify_devconf(net, NETCONFA_MC_FORWARDING, dev->ifindex,
  				    &in_dev->cnf);
  	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_get_iflink(dev);
  
  	/* And finish update writing critical data */
  	write_lock_bh(&mrt_lock);
  	v->dev = dev;
  	if (v->flags & VIFF_REGISTER)
  		mrt->mroute_reg_vif_num = vifi;
  	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;
  }
  
  /* Look for a (*,*,oif) entry */
  static struct mfc_cache *ipmr_cache_find_any_parent(struct mr_table *mrt,
  						    int vifi)
  {
  	int line = MFC_HASH(htonl(INADDR_ANY), htonl(INADDR_ANY));
  	struct mfc_cache *c;
  
  	list_for_each_entry_rcu(c, &mrt->mfc_cache_array[line], list)
  		if (c->mfc_origin == htonl(INADDR_ANY) &&
  		    c->mfc_mcastgrp == htonl(INADDR_ANY) &&
  		    c->mfc_un.res.ttls[vifi] < 255)
  			return c;
  
  	return NULL;
  }
  
  /* Look for a (*,G) entry */
  static struct mfc_cache *ipmr_cache_find_any(struct mr_table *mrt,
  					     __be32 mcastgrp, int vifi)
  {
  	int line = MFC_HASH(mcastgrp, htonl(INADDR_ANY));
  	struct mfc_cache *c, *proxy;
  
  	if (mcastgrp == htonl(INADDR_ANY))
  		goto skip;
  
  	list_for_each_entry_rcu(c, &mrt->mfc_cache_array[line], list)
  		if (c->mfc_origin == htonl(INADDR_ANY) &&
  		    c->mfc_mcastgrp == mcastgrp) {
  			if (c->mfc_un.res.ttls[vifi] < 255)
  				return c;
  
  			/* It's ok if the vifi is part of the static tree */
  			proxy = ipmr_cache_find_any_parent(mrt,
  							   c->mfc_parent);
  			if (proxy && proxy->mfc_un.res.ttls[vifi] < 255)
  				return c;
  		}
  
  skip:
  	return ipmr_cache_find_any_parent(mrt, vifi);
  }
  
  /* 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.last_assert = jiffies - MFC_ASSERT_THRESH - 1;
  		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_msg_size(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).portid);
  		} 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)
  {
  	const int ihl = ip_hdrlen(pkt);
  	struct sock *mroute_sk;
  	struct igmphdr *igmp;
  	struct igmpmsg *msg;
  	struct sk_buff *skb;
  	int ret;
  
  	if (assert == IGMPMSG_WHOLEPKT)
  		skb = skb_realloc_headroom(pkt, sizeof(struct iphdr));
  	else
  		skb = alloc_skb(128, GFP_ATOMIC);
  
  	if (!skb)
  		return -ENOBUFS;
  
  	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 {
  		/* Copy the IP header */
  		skb_set_network_header(skb, skb->len);
  		skb_put(skb, ihl);
  		skb_copy_to_linear_data(skb, pkt->data, ihl);
  		/* Flag to the kernel this is a route add */
  		ip_hdr(skb)->protocol = 0;
  		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 = assert;
  		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) {
  		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) {
  		net_warn_ratelimited("mroute: pending queue full, dropping entries\n");
  		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);
  		mroute_netlink_event(mrt, c, RTM_NEWROUTE);
  
  		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 parent)
  {
  	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 &&
  		    (parent == -1 || parent == c->mfc_parent)) {
  			list_del_rcu(&c->list);
  			mroute_netlink_event(mrt, c, RTM_DELROUTE);
  			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, int parent)
  {
  	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 &&
  		    (parent == -1 || parent == c->mfc_parent)) {
  			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);
  		mroute_netlink_event(mrt, c, RTM_NEWROUTE);
  		return 0;
  	}
  
  	if (mfc->mfcc_mcastgrp.s_addr != htonl(INADDR_ANY) &&
  	    !ipv4_is_multicast(mfc->mfcc_mcastgrp.s_addr))
  		return -EINVAL;
  
  	c = ipmr_cache_alloc();
  	if (!c)
  		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);
  	}
  	mroute_netlink_event(mrt, c, RTM_NEWROUTE);
  	return 0;
  }
  
  /* Close the multicast socket, and clear the vif tables etc */
  static void mroute_clean_tables(struct mr_table *mrt, bool all)
  {
  	int i;
  	LIST_HEAD(list);
  	struct mfc_cache *c, *next;
  
  	/* Shut down all active vif entries */
  	for (i = 0; i < mrt->maxvif; i++) {
  		if (!all && (mrt->vif_table[i].flags & VIFF_STATIC))
  			continue;
  		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 (!all && (c->mfc_flags & MFC_STATIC))
  				continue;
  			list_del_rcu(&c->list);
  			mroute_netlink_event(mrt, c, RTM_DELROUTE);
  			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);
  			mroute_netlink_event(mrt, c, RTM_DELROUTE);
  			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)--;
  			inet_netconf_notify_devconf(net, NETCONFA_MC_FORWARDING,
  						    NETCONFA_IFINDEX_ALL,
  						    net->ipv4.devconf_all);
  			RCU_INIT_POINTER(mrt->mroute_sk, NULL);
  			mroute_clean_tables(mrt, false);
  		}
  	}
  	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)
  {
  	struct net *net = sock_net(sk);
  	int val, ret = 0, parent = 0;
  	struct mr_table *mrt;
  	struct vifctl vif;
  	struct mfcctl mfc;
  	u32 uval;
  
  	/* There's one exception to the lock - MRT_DONE which needs to unlock */
  	rtnl_lock();
  	if (sk->sk_type != SOCK_RAW ||
  	    inet_sk(sk)->inet_num != IPPROTO_IGMP) {
  		ret = -EOPNOTSUPP;
  		goto out_unlock;
  	}
  
  	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
  	if (!mrt) {
  		ret = -ENOENT;
  		goto out_unlock;
  	}
  	if (optname != MRT_INIT) {
  		if (sk != rcu_access_pointer(mrt->mroute_sk) &&
  		    !ns_capable(net->user_ns, CAP_NET_ADMIN)) {
  			ret = -EACCES;
  			goto out_unlock;
  		}
  	}
  
  	switch (optname) {
  	case MRT_INIT:
  		if (optlen != sizeof(int)) {
  			ret = -EINVAL;
  			break;
  		}
  		if (rtnl_dereference(mrt->mroute_sk)) {
  			ret = -EADDRINUSE;
  			break;
  		}
  
  		ret = ip_ra_control(sk, 1, mrtsock_destruct);
  		if (ret == 0) {
  			rcu_assign_pointer(mrt->mroute_sk, sk);
  			IPV4_DEVCONF_ALL(net, MC_FORWARDING)++;
  			inet_netconf_notify_devconf(net, NETCONFA_MC_FORWARDING,
  						    NETCONFA_IFINDEX_ALL,
  						    net->ipv4.devconf_all);
  		}
  		break;
  	case MRT_DONE:
  		if (sk != rcu_access_pointer(mrt->mroute_sk)) {
  			ret = -EACCES;
  		} else {
  			/* We need to unlock here because mrtsock_destruct takes
  			 * care of rtnl itself and we can't change that due to
  			 * the IP_ROUTER_ALERT setsockopt which runs without it.
  			 */
  			rtnl_unlock();
  			ret = ip_ra_control(sk, 0, NULL);
  			goto out;
  		}
  		break;
  	case MRT_ADD_VIF:
  	case MRT_DEL_VIF:
  		if (optlen != sizeof(vif)) {
  			ret = -EINVAL;
  			break;
  		}
  		if (copy_from_user(&vif, optval, sizeof(vif))) {
  			ret = -EFAULT;
  			break;
  		}
  		if (vif.vifc_vifi >= MAXVIFS) {
  			ret = -ENFILE;
  			break;
  		}
  		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);
  		}
  		break;
  	/* Manipulate the forwarding caches. These live
  	 * in a sort of kernel/user symbiosis.
  	 */
  	case MRT_ADD_MFC:
  	case MRT_DEL_MFC:
  		parent = -1;
  	case MRT_ADD_MFC_PROXY:
  	case MRT_DEL_MFC_PROXY:
  		if (optlen != sizeof(mfc)) {
  			ret = -EINVAL;
  			break;
  		}
  		if (copy_from_user(&mfc, optval, sizeof(mfc))) {
  			ret = -EFAULT;
  			break;
  		}
  		if (parent == 0)
  			parent = mfc.mfcc_parent;
  		if (optname == MRT_DEL_MFC || optname == MRT_DEL_MFC_PROXY)
  			ret = ipmr_mfc_delete(mrt, &mfc, parent);
  		else
  			ret = ipmr_mfc_add(net, mrt, &mfc,
  					   sk == rtnl_dereference(mrt->mroute_sk),
  					   parent);
  		break;
  	/* Control PIM assert. */
  	case MRT_ASSERT:
  		if (optlen != sizeof(val)) {
  			ret = -EINVAL;
  			break;
  		}
  		if (get_user(val, (int __user *)optval)) {
  			ret = -EFAULT;
  			break;
  		}
  		mrt->mroute_do_assert = val;
  		break;
  	case MRT_PIM:
  		if (!ipmr_pimsm_enabled()) {
  			ret = -ENOPROTOOPT;
  			break;
  		}
  		if (optlen != sizeof(val)) {
  			ret = -EINVAL;
  			break;
  		}
  		if (get_user(val, (int __user *)optval)) {
  			ret = -EFAULT;
  			break;
  		}
  
  		val = !!val;
  		if (val != mrt->mroute_do_pim) {
  			mrt->mroute_do_pim = val;
  			mrt->mroute_do_assert = val;
  		}
  		break;
  	case MRT_TABLE:
  		if (!IS_BUILTIN(CONFIG_IP_MROUTE_MULTIPLE_TABLES)) {
  			ret = -ENOPROTOOPT;
  			break;
  		}
  		if (optlen != sizeof(uval)) {
  			ret = -EINVAL;
  			break;
  		}
  		if (get_user(uval, (u32 __user *)optval)) {
  			ret = -EFAULT;
  			break;
  		}
  
  		if (sk == rtnl_dereference(mrt->mroute_sk)) {
  			ret = -EBUSY;
  		} else {
  			mrt = ipmr_new_table(net, uval);
  			if (IS_ERR(mrt))
  				ret = PTR_ERR(mrt);
  			else
  				raw_sk(sk)->ipmr_table = uval;
  		}
  		break;
  	/* Spurious command, or MRT_VERSION which you cannot set. */
  	default:
  		ret = -ENOPROTOOPT;
  	}
  out_unlock:
  	rtnl_unlock();
  out:
  	return ret;
  }
  
  /* 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;
  
  	if (sk->sk_type != SOCK_RAW ||
  	    inet_sk(sk)->inet_num != IPPROTO_IGMP)
  		return -EOPNOTSUPP;
  
  	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
  	if (!mrt)
  		return -ENOENT;
  
  	switch (optname) {
  	case MRT_VERSION:
  		val = 0x0305;
  		break;
  	case MRT_PIM:
  		if (!ipmr_pimsm_enabled())
  			return -ENOPROTOOPT;
  		val = mrt->mroute_do_pim;
  		break;
  	case MRT_ASSERT:
  		val = mrt->mroute_do_assert;
  		break;
  	default:
  		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 (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)
  		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)
  		return -ENOENT;
  
  	switch (cmd) {
  	case SIOCGETVIFCNT:
  		if (copy_from_user(&vr, arg, sizeof(vr)))
  			return -EFAULT;
  		if (vr.vifi >= mrt->maxvif)
  			return -EINVAL;
  		vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
  		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 = netdev_notifier_info_to_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 net *net, 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(net, 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 net *net, struct sock *sk,
  				      struct sk_buff *skb)
  {
  	struct ip_options *opt = &(IPCB(skb)->opt);
  
  	IP_INC_STATS(net, IPSTATS_MIB_OUTFORWDATAGRAMS);
  	IP_ADD_STATS(net, IPSTATS_MIB_OUTOCTETS, skb->len);
  
  	if (unlikely(opt->optlen))
  		ip_forward_options(skb);
  
  	return dst_output(net, sk, 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)
  {
  	const struct iphdr *iph = ip_hdr(skb);
  	struct vif_device *vif = &mrt->vif_table[vifi];
  	struct net_device *dev;
  	struct rtable *rt;
  	struct flowi4 fl4;
  	int    encap = 0;
  
  	if (!vif->dev)
  		goto out_free;
  
  	if (vif->flags & VIFF_REGISTER) {
  		vif->pkt_out++;
  		vif->bytes_out += skb->len;
  		vif->dev->stats.tx_bytes += skb->len;
  		vif->dev->stats.tx_packets++;
  		ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);
  		goto out_free;
  	}
  
  	if (vif->flags & VIFF_TUNNEL) {
  		rt = ip_route_output_ports(net, &fl4, NULL,
  					   vif->remote, vif->local,
  					   0, 0,
  					   IPPROTO_IPIP,
  					   RT_TOS(iph->tos), vif->link);
  		if (IS_ERR(rt))
  			goto out_free;
  		encap = sizeof(struct iphdr);
  	} else {
  		rt = ip_route_output_ports(net, &fl4, NULL, iph->daddr, 0,
  					   0, 0,
  					   IPPROTO_IPIP,
  					   RT_TOS(iph->tos), vif->link);
  		if (IS_ERR(rt))
  			goto out_free;
  	}
  
  	dev = rt->dst.dev;
  
  	if (skb->len+encap > dst_mtu(&rt->dst) && (ntohs(iph->frag_off) & IP_DF)) {
  		/* Do not fragment multicasts. Alas, IPv4 does not
  		 * allow to send ICMP, so that packets will disappear
  		 * to blackhole.
  		 */
  		IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
  		ip_rt_put(rt);
  		goto out_free;
  	}
  
  	encap += LL_RESERVED_SPACE(dev) + rt->dst.header_len;
  
  	if (skb_cow(skb, encap)) {
  		ip_rt_put(rt);
  		goto out_free;
  	}
  
  	vif->pkt_out++;
  	vif->bytes_out += skb->len;
  
  	skb_dst_drop(skb);
  	skb_dst_set(skb, &rt->dst);
  	ip_decrease_ttl(ip_hdr(skb));
  
  	/* FIXME: forward and output firewalls used to be called here.
  	 * What do we do with netfilter? -- RR
  	 */
  	if (vif->flags & VIFF_TUNNEL) {
  		ip_encap(net, skb, vif->local, vif->remote);
  		/* FIXME: extra output firewall step used to be here. --RR */
  		vif->dev->stats.tx_packets++;
  		vif->dev->stats.tx_bytes += skb->len;
  	}
  
  	IPCB(skb)->flags |= IPSKB_FORWARDED;
  
  	/* RFC1584 teaches, that DVMRP/PIM router must deliver packets locally
  	 * not only before forwarding, but after forwarding on all output
  	 * interfaces. It is clear, if mrouter runs a multicasting
  	 * program, it should receive packets not depending to what interface
  	 * program is joined.
  	 * If we will not make it, the program will have to join on all
  	 * interfaces. On the other hand, multihoming host (or router, but
  	 * not mrouter) cannot join to more than one interface - it will
  	 * result in receiving multiple packets.
  	 */
  	NF_HOOK(NFPROTO_IPV4, NF_INET_FORWARD,
  		net, NULL, skb, skb->dev, dev,
  		ipmr_forward_finish);
  	return;
  
  out_free:
  	kfree_skb(skb);
  }
  
  static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev)
  {
  	int ct;
  
  	for (ct = mrt->maxvif-1; ct >= 0; ct--) {
  		if (mrt->vif_table[ct].dev == dev)
  			break;
  	}
  	return ct;
  }
  
  /* "local" means that we should preserve one skb (for local delivery) */
  static void ip_mr_forward(struct net *net, struct mr_table *mrt,
  			  struct sk_buff *skb, struct mfc_cache *cache,
  			  int local)
  {
  	int psend = -1;
  	int vif, ct;
  	int true_vifi = ipmr_find_vif(mrt, skb->dev);
  
  	vif = cache->mfc_parent;
  	cache->mfc_un.res.pkt++;
  	cache->mfc_un.res.bytes += skb->len;
  	cache->mfc_un.res.lastuse = jiffies;
  
  	if (cache->mfc_origin == htonl(INADDR_ANY) && true_vifi >= 0) {
  		struct mfc_cache *cache_proxy;
  
  		/* For an (*,G) entry, we only check that the incomming
  		 * interface is part of the static tree.
  		 */
  		cache_proxy = ipmr_cache_find_any_parent(mrt, vif);
  		if (cache_proxy &&
  		    cache_proxy->mfc_un.res.ttls[true_vifi] < 255)
  			goto forward;
  	}
  
  	/* Wrong interface: drop packet and (maybe) send PIM assert. */
  	if (mrt->vif_table[vif].dev != skb->dev) {
  		if (rt_is_output_route(skb_rtable(skb))) {
  			/* It is our own packet, looped back.
  			 * Very complicated situation...
  			 *
  			 * The best workaround until routing daemons will be
  			 * fixed is not to redistribute packet, if it was
  			 * send through wrong interface. It means, that
  			 * multicast applications WILL NOT work for
  			 * (S,G), which have default multicast route pointing
  			 * to wrong oif. In any case, it is not a good
  			 * idea to use multicasting applications on router.
  			 */
  			goto dont_forward;
  		}
  
  		cache->mfc_un.res.wrong_if++;
  
  		if (true_vifi >= 0 && mrt->mroute_do_assert &&
  		    /* pimsm uses asserts, when switching from RPT to SPT,
  		     * so that we cannot check that packet arrived on an oif.
  		     * It is bad, but otherwise we would need to move pretty
  		     * large chunk of pimd to kernel. Ough... --ANK
  		     */
  		    (mrt->mroute_do_pim ||
  		     cache->mfc_un.res.ttls[true_vifi] < 255) &&
  		    time_after(jiffies,
  			       cache->mfc_un.res.last_assert + MFC_ASSERT_THRESH)) {
  			cache->mfc_un.res.last_assert = jiffies;
  			ipmr_cache_report(mrt, skb, true_vifi, IGMPMSG_WRONGVIF);
  		}
  		goto dont_forward;
  	}
  
  forward:
  	mrt->vif_table[vif].pkt_in++;
  	mrt->vif_table[vif].bytes_in += skb->len;
  
  	/* Forward the frame */
  	if (cache->mfc_origin == htonl(INADDR_ANY) &&
  	    cache->mfc_mcastgrp == htonl(INADDR_ANY)) {
  		if (true_vifi >= 0 &&
  		    true_vifi != cache->mfc_parent &&
  		    ip_hdr(skb)->ttl >
  				cache->mfc_un.res.ttls[cache->mfc_parent]) {
  			/* It's an (*,*) entry and the packet is not coming from
  			 * the upstream: forward the packet to the upstream
  			 * only.
  			 */
  			psend = cache->mfc_parent;
  			goto last_forward;
  		}
  		goto dont_forward;
  	}
  	for (ct = cache->mfc_un.res.maxvif - 1;
  	     ct >= cache->mfc_un.res.minvif; ct--) {
  		/* For (*,G) entry, don't forward to the incoming interface */
  		if ((cache->mfc_origin != htonl(INADDR_ANY) ||
  		     ct != true_vifi) &&
  		    ip_hdr(skb)->ttl > cache->mfc_un.res.ttls[ct]) {
  			if (psend != -1) {
  				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
  
  				if (skb2)
  					ipmr_queue_xmit(net, mrt, skb2, cache,
  							psend);
  			}
  			psend = ct;
  		}
  	}
  last_forward:
  	if (psend != -1) {
  		if (local) {
  			struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
  
  			if (skb2)
  				ipmr_queue_xmit(net, mrt, skb2, cache, psend);
  		} else {
  			ipmr_queue_xmit(net, mrt, skb, cache, psend);
  			return;
  		}
  	}
  
  dont_forward:
  	if (!local)
  		kfree_skb(skb);
  }
  
  static struct mr_table *ipmr_rt_fib_lookup(struct net *net, struct sk_buff *skb)
  {
  	struct rtable *rt = skb_rtable(skb);
  	struct iphdr *iph = ip_hdr(skb);
  	struct flowi4 fl4 = {
  		.daddr = iph->daddr,
  		.saddr = iph->saddr,
  		.flowi4_tos = RT_TOS(iph->tos),
  		.flowi4_oif = (rt_is_output_route(rt) ?
  			       skb->dev->ifindex : 0),
  		.flowi4_iif = (rt_is_output_route(rt) ?
  			       LOOPBACK_IFINDEX :
  			       skb->dev->ifindex),
  		.flowi4_mark = skb->mark,
  	};
  	struct mr_table *mrt;
  	int err;
  
  	err = ipmr_fib_lookup(net, &fl4, &mrt);
  	if (err)
  		return ERR_PTR(err);
  	return mrt;
  }
  
  /* Multicast packets for forwarding arrive here
   * Called with rcu_read_lock();
   */
  int ip_mr_input(struct sk_buff *skb)
  {
  	struct mfc_cache *cache;
  	struct net *net = dev_net(skb->dev);
  	int local = skb_rtable(skb)->rt_flags & RTCF_LOCAL;
  	struct mr_table *mrt;
  	struct net_device *dev;
  
  	/* skb->dev passed in is the loX master dev for vrfs.
  	 * As there are no vifs associated with loopback devices,
  	 * get the proper interface that does have a vif associated with it.
  	 */
  	dev = skb->dev;
  	if (netif_is_l3_master(skb->dev)) {
  		dev = dev_get_by_index_rcu(net, IPCB(skb)->iif);
  		if (!dev) {
  			kfree_skb(skb);
  			return -ENODEV;
  		}
  	}
  
  	/* Packet is looped back after forward, it should not be
  	 * forwarded second time, but still can be delivered locally.
  	 */
  	if (IPCB(skb)->flags & IPSKB_FORWARDED)
  		goto dont_forward;
  
  	mrt = ipmr_rt_fib_lookup(net, skb);
  	if (IS_ERR(mrt)) {
  		kfree_skb(skb);
  		return PTR_ERR(mrt);
  	}
  	if (!local) {
  		if (IPCB(skb)->opt.router_alert) {
  			if (ip_call_ra_chain(skb))
  				return 0;
  		} else if (ip_hdr(skb)->protocol == IPPROTO_IGMP) {
  			/* IGMPv1 (and broken IGMPv2 implementations sort of
  			 * Cisco IOS <= 11.2(8)) do not put router alert
  			 * option to IGMP packets destined to routable
  			 * groups. It is very bad, because it means
  			 * that we can forward NO IGMP messages.
  			 */
  			struct sock *mroute_sk;
  
  			mroute_sk = rcu_dereference(mrt->mroute_sk);
  			if (mroute_sk) {
  				nf_reset(skb);
  				raw_rcv(mroute_sk, skb);
  				return 0;
  			}
  		    }
  	}
  
  	/* already under rcu_read_lock() */
  	cache = ipmr_cache_find(mrt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
  	if (!cache) {
  		int vif = ipmr_find_vif(mrt, dev);
  
  		if (vif >= 0)
  			cache = ipmr_cache_find_any(mrt, ip_hdr(skb)->daddr,
  						    vif);
  	}
  
  	/* No usable cache entry */
  	if (!cache) {
  		int vif;
  
  		if (local) {
  			struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
  			ip_local_deliver(skb);
  			if (!skb2)
  				return -ENOBUFS;
  			skb = skb2;
  		}
  
  		read_lock(&mrt_lock);
  		vif = ipmr_find_vif(mrt, dev);
  		if (vif >= 0) {
  			int err2 = ipmr_cache_unresolved(mrt, vif, skb);
  			read_unlock(&mrt_lock);
  
  			return err2;
  		}
  		read_unlock(&mrt_lock);
  		kfree_skb(skb);
  		return -ENODEV;
  	}
  
  	read_lock(&mrt_lock);
  	ip_mr_forward(net, mrt, skb, cache, local);
  	read_unlock(&mrt_lock);
  
  	if (local)
  		return ip_local_deliver(skb);
  
  	return 0;
  
  dont_forward:
  	if (local)
  		return ip_local_deliver(skb);
  	kfree_skb(skb);
  	return 0;
  }
  
  #ifdef CONFIG_IP_PIMSM_V1
  /* Handle IGMP messages of PIMv1 */
  int pim_rcv_v1(struct sk_buff *skb)
  {
  	struct igmphdr *pim;
  	struct net *net = dev_net(skb->dev);
  	struct mr_table *mrt;
  
  	if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(struct iphdr)))
  		goto drop;
  
  	pim = igmp_hdr(skb);
  
  	mrt = ipmr_rt_fib_lookup(net, skb);
  	if (IS_ERR(mrt))
  		goto drop;
  	if (!mrt->mroute_do_pim ||
  	    pim->group != PIM_V1_VERSION || pim->code != PIM_V1_REGISTER)
  		goto drop;
  
  	if (__pim_rcv(mrt, skb, sizeof(*pim))) {
  drop:
  		kfree_skb(skb);
  	}
  	return 0;
  }
  #endif
  
  #ifdef CONFIG_IP_PIMSM_V2
  static int pim_rcv(struct sk_buff *skb)
  {
  	struct pimreghdr *pim;
  	struct net *net = dev_net(skb->dev);
  	struct mr_table *mrt;
  
  	if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(struct iphdr)))
  		goto drop;
  
  	pim = (struct pimreghdr *)skb_transport_header(skb);
  	if (pim->type != ((PIM_VERSION << 4) | (PIM_REGISTER)) ||
  	    (pim->flags & PIM_NULL_REGISTER) ||
  	    (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
  	     csum_fold(skb_checksum(skb, 0, skb->len, 0))))
  		goto drop;
  
  	mrt = ipmr_rt_fib_lookup(net, skb);
  	if (IS_ERR(mrt))
  		goto drop;
  	if (__pim_rcv(mrt, skb, sizeof(*pim))) {
  drop:
  		kfree_skb(skb);
  	}
  	return 0;
  }
  #endif
  
  static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
  			      struct mfc_cache *c, struct rtmsg *rtm)
  {
  	struct rta_mfc_stats mfcs;
  	struct nlattr *mp_attr;
  	struct rtnexthop *nhp;
  	unsigned long lastuse;
  	int ct;
  
  	/* If cache is unresolved, don't try to parse IIF and OIF */
  	if (c->mfc_parent >= MAXVIFS)
  		return -ENOENT;
  
  	if (VIF_EXISTS(mrt, c->mfc_parent) &&
  	    nla_put_u32(skb, RTA_IIF, mrt->vif_table[c->mfc_parent].dev->ifindex) < 0)
  		return -EMSGSIZE;
  
  	if (!(mp_attr = nla_nest_start(skb, RTA_MULTIPATH)))
  		return -EMSGSIZE;
  
  	for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
  		if (VIF_EXISTS(mrt, ct) && c->mfc_un.res.ttls[ct] < 255) {
  			if (!(nhp = nla_reserve_nohdr(skb, sizeof(*nhp)))) {
  				nla_nest_cancel(skb, mp_attr);
  				return -EMSGSIZE;
  			}
  
  			nhp->rtnh_flags = 0;
  			nhp->rtnh_hops = c->mfc_un.res.ttls[ct];
  			nhp->rtnh_ifindex = mrt->vif_table[ct].dev->ifindex;
  			nhp->rtnh_len = sizeof(*nhp);
  		}
  	}
  
  	nla_nest_end(skb, mp_attr);
  
  	lastuse = READ_ONCE(c->mfc_un.res.lastuse);
  	lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;
  
  	mfcs.mfcs_packets = c->mfc_un.res.pkt;
  	mfcs.mfcs_bytes = c->mfc_un.res.bytes;
  	mfcs.mfcs_wrong_if = c->mfc_un.res.wrong_if;
  	if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
  	    nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
  			      RTA_PAD))
  		return -EMSGSIZE;
  
  	rtm->rtm_type = RTN_MULTICAST;
  	return 1;
  }
  
  int ipmr_get_route(struct net *net, struct sk_buff *skb,
  		   __be32 saddr, __be32 daddr,
  		   struct rtmsg *rtm, int nowait, u32 portid)
  {
  	struct mfc_cache *cache;
  	struct mr_table *mrt;
  	int err;
  
  	mrt = ipmr_get_table(net, RT_TABLE_DEFAULT);
  	if (!mrt)
  		return -ENOENT;
  
  	rcu_read_lock();
  	cache = ipmr_cache_find(mrt, saddr, daddr);
  	if (!cache && skb->dev) {
  		int vif = ipmr_find_vif(mrt, skb->dev);
  
  		if (vif >= 0)
  			cache = ipmr_cache_find_any(mrt, daddr, vif);
  	}
  	if (!cache) {
  		struct sk_buff *skb2;
  		struct iphdr *iph;
  		struct net_device *dev;
  		int vif = -1;
  
  		if (nowait) {
  			rcu_read_unlock();
  			return -EAGAIN;
  		}
  
  		dev = skb->dev;
  		read_lock(&mrt_lock);
  		if (dev)
  			vif = ipmr_find_vif(mrt, dev);
  		if (vif < 0) {
  			read_unlock(&mrt_lock);
  			rcu_read_unlock();
  			return -ENODEV;
  		}
  		skb2 = skb_clone(skb, GFP_ATOMIC);
  		if (!skb2) {
  			read_unlock(&mrt_lock);
  			rcu_read_unlock();
  			return -ENOMEM;
  		}
  
  		NETLINK_CB(skb2).portid = portid;
  		skb_push(skb2, sizeof(struct iphdr));
  		skb_reset_network_header(skb2);
  		iph = ip_hdr(skb2);
  		iph->ihl = sizeof(struct iphdr) >> 2;
  		iph->saddr = saddr;
  		iph->daddr = daddr;
  		iph->version = 0;
  		err = ipmr_cache_unresolved(mrt, vif, skb2);
  		read_unlock(&mrt_lock);
  		rcu_read_unlock();
  		return err;
  	}
  
  	read_lock(&mrt_lock);
  	err = __ipmr_fill_mroute(mrt, skb, cache, rtm);
  	read_unlock(&mrt_lock);
  	rcu_read_unlock();
  	return err;
  }
  
  static int ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
  			    u32 portid, u32 seq, struct mfc_cache *c, int cmd,
  			    int flags)
  {
  	struct nlmsghdr *nlh;
  	struct rtmsg *rtm;
  	int err;
  
  	nlh = nlmsg_put(skb, portid, seq, cmd, sizeof(*rtm), flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	rtm = nlmsg_data(nlh);
  	rtm->rtm_family   = RTNL_FAMILY_IPMR;
  	rtm->rtm_dst_len  = 32;
  	rtm->rtm_src_len  = 32;
  	rtm->rtm_tos      = 0;
  	rtm->rtm_table    = mrt->id;
  	if (nla_put_u32(skb, RTA_TABLE, mrt->id))
  		goto nla_put_failure;
  	rtm->rtm_type     = RTN_MULTICAST;
  	rtm->rtm_scope    = RT_SCOPE_UNIVERSE;
  	if (c->mfc_flags & MFC_STATIC)
  		rtm->rtm_protocol = RTPROT_STATIC;
  	else
  		rtm->rtm_protocol = RTPROT_MROUTED;
  	rtm->rtm_flags    = 0;
  
  	if (nla_put_in_addr(skb, RTA_SRC, c->mfc_origin) ||
  	    nla_put_in_addr(skb, RTA_DST, c->mfc_mcastgrp))
  		goto nla_put_failure;
  	err = __ipmr_fill_mroute(mrt, skb, c, rtm);
  	/* do not break the dump if cache is unresolved */
  	if (err < 0 && err != -ENOENT)
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return 0;
  
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -EMSGSIZE;
  }
  
  static size_t mroute_msgsize(bool unresolved, int maxvif)
  {
  	size_t len =
  		NLMSG_ALIGN(sizeof(struct rtmsg))
  		+ nla_total_size(4)	/* RTA_TABLE */
  		+ nla_total_size(4)	/* RTA_SRC */
  		+ nla_total_size(4)	/* RTA_DST */
  		;
  
  	if (!unresolved)
  		len = len
  		      + nla_total_size(4)	/* RTA_IIF */
  		      + nla_total_size(0)	/* RTA_MULTIPATH */
  		      + maxvif * NLA_ALIGN(sizeof(struct rtnexthop))
  						/* RTA_MFC_STATS */
  		      + nla_total_size_64bit(sizeof(struct rta_mfc_stats))
  		;
  
  	return len;
  }
  
  static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,
  				 int cmd)
  {
  	struct net *net = read_pnet(&mrt->net);
  	struct sk_buff *skb;
  	int err = -ENOBUFS;
  
  	skb = nlmsg_new(mroute_msgsize(mfc->mfc_parent >= MAXVIFS, mrt->maxvif),
  			GFP_ATOMIC);
  	if (!skb)
  		goto errout;
  
  	err = ipmr_fill_mroute(mrt, skb, 0, 0, mfc, cmd, 0);
  	if (err < 0)
  		goto errout;
  
  	rtnl_notify(skb, net, 0, RTNLGRP_IPV4_MROUTE, NULL, GFP_ATOMIC);
  	return;
  
  errout:
  	kfree_skb(skb);
  	if (err < 0)
  		rtnl_set_sk_err(net, RTNLGRP_IPV4_MROUTE, err);
  }
  
  static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	struct mr_table *mrt;
  	struct mfc_cache *mfc;
  	unsigned int t = 0, s_t;
  	unsigned int h = 0, s_h;
  	unsigned int e = 0, s_e;
  
  	s_t = cb->args[0];
  	s_h = cb->args[1];
  	s_e = cb->args[2];
  
  	rcu_read_lock();
  	ipmr_for_each_table(mrt, net) {
  		if (t < s_t)
  			goto next_table;
  		if (t > s_t)
  			s_h = 0;
  		for (h = s_h; h < MFC_LINES; h++) {
  			list_for_each_entry_rcu(mfc, &mrt->mfc_cache_array[h], list) {
  				if (e < s_e)
  					goto next_entry;
  				if (ipmr_fill_mroute(mrt, skb,
  						     NETLINK_CB(cb->skb).portid,
  						     cb->nlh->nlmsg_seq,
  						     mfc, RTM_NEWROUTE,
  						     NLM_F_MULTI) < 0)
  					goto done;
  next_entry:
  				e++;
  			}
  			e = s_e = 0;
  		}
  		spin_lock_bh(&mfc_unres_lock);
  		list_for_each_entry(mfc, &mrt->mfc_unres_queue, list) {
  			if (e < s_e)
  				goto next_entry2;
  			if (ipmr_fill_mroute(mrt, skb,
  					     NETLINK_CB(cb->skb).portid,
  					     cb->nlh->nlmsg_seq,
  					     mfc, RTM_NEWROUTE,
  					     NLM_F_MULTI) < 0) {
  				spin_unlock_bh(&mfc_unres_lock);
  				goto done;
  			}
  next_entry2:
  			e++;
  		}
  		spin_unlock_bh(&mfc_unres_lock);
  		e = s_e = 0;
  		s_h = 0;
  next_table:
  		t++;
  	}
  done:
  	rcu_read_unlock();
  
  	cb->args[2] = e;
  	cb->args[1] = h;
  	cb->args[0] = t;
  
  	return skb->len;
  }
  
  static const struct nla_policy rtm_ipmr_policy[RTA_MAX + 1] = {
  	[RTA_SRC]	= { .type = NLA_U32 },
  	[RTA_DST]	= { .type = NLA_U32 },
  	[RTA_IIF]	= { .type = NLA_U32 },
  	[RTA_TABLE]	= { .type = NLA_U32 },
  	[RTA_MULTIPATH]	= { .len = sizeof(struct rtnexthop) },
  };
  
  static bool ipmr_rtm_validate_proto(unsigned char rtm_protocol)
  {
  	switch (rtm_protocol) {
  	case RTPROT_STATIC:
  	case RTPROT_MROUTED:
  		return true;
  	}
  	return false;
  }
  
  static int ipmr_nla_get_ttls(const struct nlattr *nla, struct mfcctl *mfcc)
  {
  	struct rtnexthop *rtnh = nla_data(nla);
  	int remaining = nla_len(nla), vifi = 0;
  
  	while (rtnh_ok(rtnh, remaining)) {
  		mfcc->mfcc_ttls[vifi] = rtnh->rtnh_hops;
  		if (++vifi == MAXVIFS)
  			break;
  		rtnh = rtnh_next(rtnh, &remaining);
  	}
  
  	return remaining > 0 ? -EINVAL : vifi;
  }
  
  /* returns < 0 on error, 0 for ADD_MFC and 1 for ADD_MFC_PROXY */
  static int rtm_to_ipmr_mfcc(struct net *net, struct nlmsghdr *nlh,
  			    struct mfcctl *mfcc, int *mrtsock,
  			    struct mr_table **mrtret)
  {
  	struct net_device *dev = NULL;
  	u32 tblid = RT_TABLE_DEFAULT;
  	struct mr_table *mrt;
  	struct nlattr *attr;
  	struct rtmsg *rtm;
  	int ret, rem;
  
  	ret = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipmr_policy);
  	if (ret < 0)
  		goto out;
  	rtm = nlmsg_data(nlh);
  
  	ret = -EINVAL;
  	if (rtm->rtm_family != RTNL_FAMILY_IPMR || rtm->rtm_dst_len != 32 ||
  	    rtm->rtm_type != RTN_MULTICAST ||
  	    rtm->rtm_scope != RT_SCOPE_UNIVERSE ||
  	    !ipmr_rtm_validate_proto(rtm->rtm_protocol))
  		goto out;
  
  	memset(mfcc, 0, sizeof(*mfcc));
  	mfcc->mfcc_parent = -1;
  	ret = 0;
  	nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), rem) {
  		switch (nla_type(attr)) {
  		case RTA_SRC:
  			mfcc->mfcc_origin.s_addr = nla_get_be32(attr);
  			break;
  		case RTA_DST:
  			mfcc->mfcc_mcastgrp.s_addr = nla_get_be32(attr);
  			break;
  		case RTA_IIF:
  			dev = __dev_get_by_index(net, nla_get_u32(attr));
  			if (!dev) {
  				ret = -ENODEV;
  				goto out;
  			}
  			break;
  		case RTA_MULTIPATH:
  			if (ipmr_nla_get_ttls(attr, mfcc) < 0) {
  				ret = -EINVAL;
  				goto out;
  			}
  			break;
  		case RTA_PREFSRC:
  			ret = 1;
  			break;
  		case RTA_TABLE:
  			tblid = nla_get_u32(attr);
  			break;
  		}
  	}
  	mrt = ipmr_get_table(net, tblid);
  	if (!mrt) {
  		ret = -ENOENT;
  		goto out;
  	}
  	*mrtret = mrt;
  	*mrtsock = rtm->rtm_protocol == RTPROT_MROUTED ? 1 : 0;
  	if (dev)
  		mfcc->mfcc_parent = ipmr_find_vif(mrt, dev);
  
  out:
  	return ret;
  }
  
  /* takes care of both newroute and delroute */
  static int ipmr_rtm_route(struct sk_buff *skb, struct nlmsghdr *nlh)
  {
  	struct net *net = sock_net(skb->sk);
  	int ret, mrtsock, parent;
  	struct mr_table *tbl;
  	struct mfcctl mfcc;
  
  	mrtsock = 0;
  	tbl = NULL;
  	ret = rtm_to_ipmr_mfcc(net, nlh, &mfcc, &mrtsock, &tbl);
  	if (ret < 0)
  		return ret;
  
  	parent = ret ? mfcc.mfcc_parent : -1;
  	if (nlh->nlmsg_type == RTM_NEWROUTE)
  		return ipmr_mfc_add(net, tbl, &mfcc, mrtsock, parent);
  	else
  		return ipmr_mfc_delete(tbl, &mfcc, parent);
  }
  
  #ifdef CONFIG_PROC_FS
  /* The /proc interfaces to multicast routing :
   * /proc/net/ip_mr_cache & /proc/net/ip_mr_vif
   */
  struct ipmr_vif_iter {
  	struct seq_net_private p;
  	struct mr_table *mrt;
  	int ct;
  };
  
  static struct vif_device *ipmr_vif_seq_idx(struct net *net,
  					   struct ipmr_vif_iter *iter,
  					   loff_t pos)
  {
  	struct mr_table *mrt = iter->mrt;
  
  	for (iter->ct = 0; iter->ct < mrt->maxvif; ++iter->ct) {
  		if (!VIF_EXISTS(mrt, iter->ct))
  			continue;
  		if (pos-- == 0)
  			return &mrt->vif_table[iter->ct];
  	}
  	return NULL;
  }
  
  static void *ipmr_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 mr_table *mrt;
  
  	mrt = ipmr_get_table(net, RT_TABLE_DEFAULT);
  	if (!mrt)
  		return ERR_PTR(-ENOENT);
  
  	iter->mrt = mrt;
  
  	read_lock(&mrt_lock);
  	return *pos ? ipmr_vif_seq_idx(net, seq->private, *pos - 1)
  		: SEQ_START_TOKEN;
  }
  
  static void *ipmr_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 mr_table *mrt = iter->mrt;
  
  	++*pos;
  	if (v == SEQ_START_TOKEN)
  		return ipmr_vif_seq_idx(net, iter, 0);
  
  	while (++iter->ct < mrt->maxvif) {
  		if (!VIF_EXISTS(mrt, iter->ct))
  			continue;
  		return &mrt->vif_table[iter->ct];
  	}
  	return NULL;
  }
  
  static void ipmr_vif_seq_stop(struct seq_file *seq, void *v)
  	__releases(mrt_lock)
  {
  	read_unlock(&mrt_lock);
  }
  
  static int ipmr_vif_seq_show(struct seq_file *seq, void *v)
  {
  	struct ipmr_vif_iter *iter = seq->private;
  	struct mr_table *mrt = iter->mrt;
  
  	if (v == SEQ_START_TOKEN) {
  		seq_puts(seq,
  			 "Interface      BytesIn  PktsIn  BytesOut PktsOut Flags Local    Remote\n");
  	} else {
  		const struct vif_device *vif = v;
  		const char *name =  vif->dev ? vif->dev->name : "none";
  
  		seq_printf(seq,
  			   "%2Zd %-10s %8ld %7ld  %8ld %7ld %05X %08X %08X\n",
  			   vif - mrt->vif_table,
  			   name, vif->bytes_in, vif->pkt_in,
  			   vif->bytes_out, vif->pkt_out,
  			   vif->flags, vif->local, vif->remote);
  	}
  	return 0;
  }
  
  static const struct seq_operations ipmr_vif_seq_ops = {
  	.start = ipmr_vif_seq_start,
  	.next  = ipmr_vif_seq_next,
  	.stop  = ipmr_vif_seq_stop,
  	.show  = ipmr_vif_seq_show,
  };
  
  static int ipmr_vif_open(struct inode *inode, struct file *file)
  {
  	return seq_open_net(inode, file, &ipmr_vif_seq_ops,
  			    sizeof(struct ipmr_vif_iter));
  }
  
  static const struct file_operations ipmr_vif_fops = {
  	.owner	 = THIS_MODULE,
  	.open    = ipmr_vif_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release_net,
  };
  
  struct ipmr_mfc_iter {
  	struct seq_net_private p;
  	struct mr_table *mrt;
  	struct list_head *cache;
  	int ct;
  };
  
  
  static struct mfc_cache *ipmr_mfc_seq_idx(struct net *net,
  					  struct ipmr_mfc_iter *it, loff_t pos)
  {
  	struct mr_table *mrt = it->mrt;
  	struct mfc_cache *mfc;
  
  	rcu_read_lock();
  	for (it->ct = 0; it->ct < MFC_LINES; it->ct++) {
  		it->cache = &mrt->mfc_cache_array[it->ct];
  		list_for_each_entry_rcu(mfc, it->cache, list)
  			if (pos-- == 0)
  				return mfc;
  	}
  	rcu_read_unlock();
  
  	spin_lock_bh(&mfc_unres_lock);
  	it->cache = &mrt->mfc_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;
  }
  
  
  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 mr_table *mrt;
  
  	mrt = ipmr_get_table(net, RT_TABLE_DEFAULT);
  	if (!mrt)
  		return ERR_PTR(-ENOENT);
  
  	it->mrt = mrt;
  	it->cache = NULL;
  	it->ct = 0;
  	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 mfc_cache *mfc = v;
  	struct ipmr_mfc_iter *it = seq->private;
  	struct net *net = seq_file_net(seq);
  	struct mr_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 mfc_cache, list);
  
  	if (it->cache == &mrt->mfc_unres_queue)
  		goto end_of_list;
  
  	BUG_ON(it->cache != &mrt->mfc_cache_array[it->ct]);
  
  	while (++it->ct < MFC_LINES) {
  		it->cache = &mrt->mfc_cache_array[it->ct];
  		if (list_empty(it->cache))
  			continue;
  		return list_first_entry(it->cache, struct mfc_cache, list);
  	}
  
  	/* exhausted cache_array, show unresolved */
  	rcu_read_unlock();
  	it->cache = &mrt->mfc_unres_queue;
  	it->ct = 0;
  
  	spin_lock_bh(&mfc_unres_lock);
  	if (!list_empty(it->cache))
  		return list_first_entry(it->cache, struct mfc_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 mr_table *mrt = it->mrt;
  
  	if (it->cache == &mrt->mfc_unres_queue)
  		spin_unlock_bh(&mfc_unres_lock);
  	else if (it->cache == &mrt->mfc_cache_array[it->ct])
  		rcu_read_unlock();
  }
  
  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\n");
  	} else {
  		const struct mfc_cache *mfc = v;
  		const struct ipmr_mfc_iter *it = seq->private;
  		const struct mr_table *mrt = it->mrt;
  
  		seq_printf(seq, "%08X %08X %-3hd",
  			   (__force u32) mfc->mfc_mcastgrp,
  			   (__force u32) mfc->mfc_origin,
  			   mfc->mfc_parent);
  
  		if (it->cache != &mrt->mfc_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 (VIF_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, '\n');
  	}
  	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 ipmr_mfc_fops = {
  	.owner	 = THIS_MODULE,
  	.open    = ipmr_mfc_open,
  	.read    = seq_read,
  	.llseek  = seq_lseek,
  	.release = seq_release_net,
  };
  #endif
  
  #ifdef CONFIG_IP_PIMSM_V2
  static const struct net_protocol pim_protocol = {
  	.handler	=	pim_rcv,
  	.netns_ok	=	1,
  };
  #endif
  
  /* Setup for IP multicast routing */
  static int __net_init ipmr_net_init(struct net *net)
  {
  	int err;
  
  	err = ipmr_rules_init(net);
  	if (err < 0)
  		goto fail;
  
  #ifdef CONFIG_PROC_FS
  	err = -ENOMEM;
  	if (!proc_create("ip_mr_vif", 0, net->proc_net, &ipmr_vif_fops))
  		goto proc_vif_fail;
  	if (!proc_create("ip_mr_cache", 0, net->proc_net, &ipmr_mfc_fops))
  		goto proc_cache_fail;
  #endif
  	return 0;
  
  #ifdef CONFIG_PROC_FS
  proc_cache_fail:
  	remove_proc_entry("ip_mr_vif", net->proc_net);
  proc_vif_fail:
  	ipmr_rules_exit(net);
  #endif
  fail:
  	return err;
  }
  
  static void __net_exit ipmr_net_exit(struct net *net)
  {
  #ifdef CONFIG_PROC_FS
  	remove_proc_entry("ip_mr_cache", net->proc_net);
  	remove_proc_entry("ip_mr_vif", net->proc_net);
  #endif
  	ipmr_rules_exit(net);
  }
  
  static struct pernet_operations ipmr_net_ops = {
  	.init = ipmr_net_init,
  	.exit = ipmr_net_exit,
  };
  
  int __init ip_mr_init(void)
  {
  	int err;
  
  	mrt_cachep = kmem_cache_create("ip_mrt_cache",
  				       sizeof(struct mfc_cache),
  				       0, SLAB_HWCACHE_ALIGN | SLAB_PANIC,
  				       NULL);
  
  	err = register_pernet_subsys(&ipmr_net_ops);
  	if (err)
  		goto reg_pernet_fail;
  
  	err = register_netdevice_notifier(&ip_mr_notifier);
  	if (err)
  		goto reg_notif_fail;
  #ifdef CONFIG_IP_PIMSM_V2
  	if (inet_add_protocol(&pim_protocol, IPPROTO_PIM) < 0) {
  		pr_err("%s: can't add PIM protocol\n", __func__);
  		err = -EAGAIN;
  		goto add_proto_fail;
  	}
  #endif
  	rtnl_register(RTNL_FAMILY_IPMR, RTM_GETROUTE,
  		      NULL, ipmr_rtm_dumproute, NULL);
  	rtnl_register(RTNL_FAMILY_IPMR, RTM_NEWROUTE,
  		      ipmr_rtm_route, NULL, NULL);
  	rtnl_register(RTNL_FAMILY_IPMR, RTM_DELROUTE,
  		      ipmr_rtm_route, NULL, NULL);
  	return 0;
  
  #ifdef CONFIG_IP_PIMSM_V2
  add_proto_fail:
  	unregister_netdevice_notifier(&ip_mr_notifier);
  #endif
  reg_notif_fail:
  	unregister_pernet_subsys(&ipmr_net_ops);
  reg_pernet_fail:
  	kmem_cache_destroy(mrt_cachep);
  	return err;
  }
  