net/ipv6/ip6mr.c

/*
 *	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 <asm/system.h>
#include <asm/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/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 <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/raw.h>
#include <net/route.h>
#include <linux/notifier.h>
#include <linux/if_arp.h>
#include <linux/netfilter_ipv4.h>
#include <net/ipip.h>
#include <net/checksum.h>
#include <net/netlink.h>

#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <linux/mroute6.h>
#include <net/addrconf.h>
#include <linux/netfilter_ipv6.h>

struct sock *mroute6_socket;


/* 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
 */

static struct mif_device vif6_table[MAXMIFS];		/* Devices 		*/
static int maxvif;

#define MIF_EXISTS(idx) (vif6_table[idx].dev != NULL)

static struct mfc6_cache *mfc6_cache_array[MFC_LINES];	/* Forwarding cache	*/

static struct mfc6_cache *mfc_unres_queue;		/* Queue of unresolved entries */
static atomic_t cache_resolve_queue_len;		/* Size of unresolved	*/

/* 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 int ip6_mr_forward(struct sk_buff *skb, struct mfc6_cache *cache);
static int ip6mr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert);
static int ip6mr_fill_mroute(struct sk_buff *skb, struct mfc6_cache *c, struct rtmsg *rtm);

static struct timer_list ipmr_expire_timer;


#ifdef CONFIG_PROC_FS

struct ipmr_mfc_iter {
	struct mfc6_cache **cache;
	int ct;
};


static struct mfc6_cache *ipmr_mfc_seq_idx(struct ipmr_mfc_iter *it, loff_t pos)
{
	struct mfc6_cache *mfc;

	it->cache = mfc6_cache_array;
	read_lock(&mrt_lock);
	for (it->ct = 0; it->ct < ARRAY_SIZE(mfc6_cache_array); it->ct++)
		for (mfc = mfc6_cache_array[it->ct]; mfc; mfc = mfc->next)
			if (pos-- == 0)
				return mfc;
	read_unlock(&mrt_lock);

	it->cache = &mfc_unres_queue;
	spin_lock_bh(&mfc_unres_lock);
	for (mfc = mfc_unres_queue; mfc; mfc = mfc->next)
		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 {
	int ct;
};

static struct mif_device *ip6mr_vif_seq_idx(struct ipmr_vif_iter *iter,
					    loff_t pos)
{
	for (iter->ct = 0; iter->ct < maxvif; ++iter->ct) {
		if (!MIF_EXISTS(iter->ct))
			continue;
		if (pos-- == 0)
			return &vif6_table[iter->ct];
	}
	return NULL;
}

static void *ip6mr_vif_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(mrt_lock)
{
	read_lock(&mrt_lock);
	return (*pos ? ip6mr_vif_seq_idx(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;

	++*pos;
	if (v == SEQ_START_TOKEN)
		return ip6mr_vif_seq_idx(iter, 0);

	while (++iter->ct < maxvif) {
		if (!MIF_EXISTS(iter->ct))
			continue;
		return &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)
{
	if (v == SEQ_START_TOKEN) {
		seq_puts(seq,
			 "Interface      BytesIn  PktsIn  BytesOut PktsOut Flags\n");
	} else {
		const struct mif_device *vif = v;
		const char *name = vif->dev ? vif->dev->name : "none";

		seq_printf(seq,
			   "%2Zd %-10s %8ld %7ld  %8ld %7ld %05X\n",
			   vif - vif6_table,
			   name, vif->bytes_in, vif->pkt_in,
			   vif->bytes_out, vif->pkt_out,
			   vif->flags);
	}
	return 0;
}

static 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_private(file, &ip6mr_vif_seq_ops,
				sizeof(struct ipmr_vif_iter));
}

static struct file_operations ip6mr_vif_fops = {
	.owner	 = THIS_MODULE,
	.open    = ip6mr_vif_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};

static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
{
	return (*pos ? ipmr_mfc_seq_idx(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;

	++*pos;

	if (v == SEQ_START_TOKEN)
		return ipmr_mfc_seq_idx(seq->private, 0);

	if (mfc->next)
		return mfc->next;

	if (it->cache == &mfc_unres_queue)
		goto end_of_list;

	BUG_ON(it->cache != mfc6_cache_array);

	while (++it->ct < ARRAY_SIZE(mfc6_cache_array)) {
		mfc = mfc6_cache_array[it->ct];
		if (mfc)
			return mfc;
	}

	/* exhausted cache_array, show unresolved */
	read_unlock(&mrt_lock);
	it->cache = &mfc_unres_queue;
	it->ct = 0;

	spin_lock_bh(&mfc_unres_lock);
	mfc = mfc_unres_queue;
	if (mfc)
		return mfc;

 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;

	if (it->cache == &mfc_unres_queue)
		spin_unlock_bh(&mfc_unres_lock);
	else if (it->cache == mfc6_cache_array)
		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\n");
	} else {
		const struct mfc6_cache *mfc = v;
		const struct ipmr_mfc_iter *it = seq->private;

		seq_printf(seq,
			   NIP6_FMT " " NIP6_FMT " %-3d %8ld %8ld %8ld",
			   NIP6(mfc->mf6c_mcastgrp), NIP6(mfc->mf6c_origin),
			   mfc->mf6c_parent,
			   mfc->mfc_un.res.pkt,
			   mfc->mfc_un.res.bytes,
			   mfc->mfc_un.res.wrong_if);

		if (it->cache != &mfc_unres_queue) {
			for (n = mfc->mfc_un.res.minvif;
			     n < mfc->mfc_un.res.maxvif; n++) {
				if (MIF_EXISTS(n) &&
				    mfc->mfc_un.res.ttls[n] < 255)
					seq_printf(seq,
						   " %2d:%-3d",
						   n, mfc->mfc_un.res.ttls[n]);
			}
		}
		seq_putc(seq, '\n');
	}
	return 0;
}

static 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_private(file, &ipmr_mfc_seq_ops,
				sizeof(struct ipmr_mfc_iter));
}

static struct file_operations ip6mr_mfc_fops = {
	.owner	 = THIS_MODULE,
	.open    = ipmr_mfc_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};
#endif

/*
 *	Delete a VIF entry
 */

static int mif6_delete(int vifi)
{
	struct mif_device *v;
	struct net_device *dev;
	if (vifi < 0 || vifi >= maxvif)
		return -EADDRNOTAVAIL;

	v = &vif6_table[vifi];

	write_lock_bh(&mrt_lock);
	dev = v->dev;
	v->dev = NULL;

	if (!dev) {
		write_unlock_bh(&mrt_lock);
		return -EADDRNOTAVAIL;
	}

	if (vifi + 1 == maxvif) {
		int tmp;
		for (tmp = vifi - 1; tmp >= 0; tmp--) {
			if (MIF_EXISTS(tmp))
				break;
		}
		maxvif = tmp + 1;
	}

	write_unlock_bh(&mrt_lock);

	dev_set_allmulti(dev, -1);

	if (v->flags & MIFF_REGISTER)
		unregister_netdevice(dev);

	dev_put(dev);
	return 0;
}

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

static void ip6mr_destroy_unres(struct mfc6_cache *c)
{
	struct sk_buff *skb;

	atomic_dec(&cache_resolve_queue_len);

	while((skb = skb_dequeue(&c->mfc_un.unres.unresolved)) != NULL) {
		if (ipv6_hdr(skb)->version == 0) {
			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct ipv6hdr));
			nlh->nlmsg_type = NLMSG_ERROR;
			nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
			skb_trim(skb, nlh->nlmsg_len);
			((struct nlmsgerr *)NLMSG_DATA(nlh))->error = -ETIMEDOUT;
			rtnl_unicast(skb, &init_net, NETLINK_CB(skb).pid);
		} else
			kfree_skb(skb);
	}

	kmem_cache_free(mrt_cachep, c);
}


/* Single timer process for all the unresolved queue. */

static void ipmr_do_expire_process(unsigned long dummy)
{
	unsigned long now = jiffies;
	unsigned long expires = 10 * HZ;
	struct mfc6_cache *c, **cp;

	cp = &mfc_unres_queue;

	while ((c = *cp) != NULL) {
		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;
			cp = &c->next;
			continue;
		}

		*cp = c->next;
		ip6mr_destroy_unres(c);
	}

	if (atomic_read(&cache_resolve_queue_len))
		mod_timer(&ipmr_expire_timer, jiffies + expires);
}

static void ipmr_expire_process(unsigned long dummy)
{
	if (!spin_trylock(&mfc_unres_lock)) {
		mod_timer(&ipmr_expire_timer, jiffies + 1);
		return;
	}

	if (atomic_read(&cache_resolve_queue_len))
		ipmr_do_expire_process(dummy);

	spin_unlock(&mfc_unres_lock);
}

/* Fill oifs list. It is called under write locked mrt_lock. */

static void ip6mr_update_thresholds(struct mfc6_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 < maxvif; vifi++) {
		if (MIF_EXISTS(vifi) && ttls[vifi] && ttls[vifi] < 255) {
			cache->mfc_un.res.ttls[vifi] = ttls[vifi];
			if (cache->mfc_un.res.minvif > vifi)
				cache->mfc_un.res.minvif = vifi;
			if (cache->mfc_un.res.maxvif <= vifi)
				cache->mfc_un.res.maxvif = vifi + 1;
		}
	}
}

static int mif6_add(struct mif6ctl *vifc, int mrtsock)
{
	int vifi = vifc->mif6c_mifi;
	struct mif_device *v = &vif6_table[vifi];
	struct net_device *dev;

	/* Is vif busy ? */
	if (MIF_EXISTS(vifi))
		return -EADDRINUSE;

	switch (vifc->mif6c_flags) {
	case 0:
		dev = dev_get_by_index(&init_net, vifc->mif6c_pifi);
		if (!dev)
			return -EADDRNOTAVAIL;
		dev_put(dev);
		break;
	default:
		return -EINVAL;
	}

	dev_set_allmulti(dev, 1);

	/*
	 *	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->iflink;

	/* And finish update writing critical data */
	write_lock_bh(&mrt_lock);
	dev_hold(dev);
	v->dev = dev;
	if (vifi + 1 > maxvif)
		maxvif = vifi + 1;
	write_unlock_bh(&mrt_lock);
	return 0;
}

static struct mfc6_cache *ip6mr_cache_find(struct in6_addr *origin, struct in6_addr *mcastgrp)
{
	int line = MFC6_HASH(mcastgrp, origin);
	struct mfc6_cache *c;

	for (c = mfc6_cache_array[line]; c; c = c->next) {
		if (ipv6_addr_equal(&c->mf6c_origin, origin) &&
		    ipv6_addr_equal(&c->mf6c_mcastgrp, mcastgrp))
			break;
	}
	return c;
}

/*
 *	Allocate a multicast cache entry
 */
static struct mfc6_cache *ip6mr_cache_alloc(void)
{
	struct mfc6_cache *c = kmem_cache_alloc(mrt_cachep, GFP_KERNEL);
	if (c == NULL)
		return NULL;
	memset(c, 0, sizeof(*c));
	c->mfc_un.res.minvif = MAXVIFS;
	return c;
}

static struct mfc6_cache *ip6mr_cache_alloc_unres(void)
{
	struct mfc6_cache *c = kmem_cache_alloc(mrt_cachep, GFP_ATOMIC);
	if (c == NULL)
		return NULL;
	memset(c, 0, sizeof(*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 ip6mr_cache_resolve(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) {
			int err;
			struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct ipv6hdr));

			if (ip6mr_fill_mroute(skb, c, NLMSG_DATA(nlh)) > 0) {
				nlh->nlmsg_len = skb->tail - (u8 *)nlh;
			} else {
				nlh->nlmsg_type = NLMSG_ERROR;
				nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
				skb_trim(skb, nlh->nlmsg_len);
				((struct nlmsgerr *)NLMSG_DATA(nlh))->error = -EMSGSIZE;
			}
			err = rtnl_unicast(skb, &init_net, NETLINK_CB(skb).pid);
		} else
			ip6_mr_forward(skb, c);
	}
}

/*
 *	Bounce a cache query up to pim6sd. We could use netlink for this but pim6sd
 *	expects the following bizarre scheme.
 *
 *	Called under mrt_lock.
 */

static int ip6mr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert)
{
	struct sk_buff *skb;
	struct mrt6msg *msg;
	int ret;

	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;

	/*
	 *	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 = vifi;
	msg->im6_pad = 0;
	ipv6_addr_copy(&msg->im6_src, &ipv6_hdr(pkt)->saddr);
	ipv6_addr_copy(&msg->im6_dst, &ipv6_hdr(pkt)->daddr);

	skb->dst = dst_clone(pkt->dst);
	skb->ip_summed = CHECKSUM_UNNECESSARY;

	skb_pull(skb, sizeof(struct ipv6hdr));

	if (mroute6_socket == NULL) {
		kfree_skb(skb);
		return -EINVAL;
	}

	/*
	 *	Deliver to user space multicast routing algorithms
	 */
	if ((ret = sock_queue_rcv_skb(mroute6_socket, skb)) < 0) {
		if (net_ratelimit())
			printk(KERN_WARNING "mroute6: pending queue full, dropping entries.\n");
		kfree_skb(skb);
	}

	return ret;
}

/*
 *	Queue a packet for resolution. It gets locked cache entry!
 */

static int
ip6mr_cache_unresolved(vifi_t vifi, struct sk_buff *skb)
{
	int err;
	struct mfc6_cache *c;

	spin_lock_bh(&mfc_unres_lock);
	for (c = mfc_unres_queue; c; c = c->next) {
		if (ipv6_addr_equal(&c->mf6c_mcastgrp, &ipv6_hdr(skb)->daddr) &&
		    ipv6_addr_equal(&c->mf6c_origin, &ipv6_hdr(skb)->saddr))
			break;
	}

	if (c == NULL) {
		/*
		 *	Create a new entry if allowable
		 */

		if (atomic_read(&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
		 */
		if ((err = ip6mr_cache_report(skb, vifi, MRT6MSG_NOCACHE)) < 0) {
			/* If the report failed throw the cache entry
			   out - Brad Parker
			 */
			spin_unlock_bh(&mfc_unres_lock);

			kmem_cache_free(mrt_cachep, c);
			kfree_skb(skb);
			return err;
		}

		atomic_inc(&cache_resolve_queue_len);
		c->next = mfc_unres_queue;
		mfc_unres_queue = c;

		ipmr_do_expire_process(1);
	}

	/*
	 *	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 mf6cctl *mfc)
{
	int line;
	struct mfc6_cache *c, **cp;

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

	for (cp = &mfc6_cache_array[line]; (c = *cp) != NULL; cp = &c->next) {
		if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&
		    ipv6_addr_equal(&c->mf6c_mcastgrp, &mfc->mf6cc_mcastgrp.sin6_addr)) {
			write_lock_bh(&mrt_lock);
			*cp = c->next;
			write_unlock_bh(&mrt_lock);

			kmem_cache_free(mrt_cachep, c);
			return 0;
		}
	}
	return -ENOENT;
}

static int ip6mr_device_event(struct notifier_block *this,
			      unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;
	struct mif_device *v;
	int ct;

	if (dev_net(dev) != &init_net)
		return NOTIFY_DONE;

	if (event != NETDEV_UNREGISTER)
		return NOTIFY_DONE;

	v = &vif6_table[0];
	for (ct = 0; ct < maxvif; ct++, v++) {
		if (v->dev == dev)
			mif6_delete(ct);
	}
	return NOTIFY_DONE;
}

static struct notifier_block ip6_mr_notifier = {
	.notifier_call = ip6mr_device_event
};

/*
 *	Setup for IP multicast routing
 */

void __init ip6_mr_init(void)
{
	mrt_cachep = kmem_cache_create("ip6_mrt_cache",
				       sizeof(struct mfc6_cache),
				       0, SLAB_HWCACHE_ALIGN,
				       NULL);
	if (!mrt_cachep)
		panic("cannot allocate ip6_mrt_cache");

	setup_timer(&ipmr_expire_timer, ipmr_expire_process, 0);
	register_netdevice_notifier(&ip6_mr_notifier);
#ifdef CONFIG_PROC_FS
	proc_net_fops_create(&init_net, "ip6_mr_vif", 0, &ip6mr_vif_fops);
	proc_net_fops_create(&init_net, "ip6_mr_cache", 0, &ip6mr_mfc_fops);
#endif
}


static int ip6mr_mfc_add(struct mf6cctl *mfc, int mrtsock)
{
	int line;
	struct mfc6_cache *uc, *c, **cp;
	unsigned char ttls[MAXVIFS];
	int i;

	memset(ttls, 255, MAXVIFS);
	for (i = 0; i < MAXVIFS; i++) {
		if (IF_ISSET(i, &mfc->mf6cc_ifset))
			ttls[i] = 1;

	}

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

	for (cp = &mfc6_cache_array[line]; (c = *cp) != NULL; cp = &c->next) {
		if (ipv6_addr_equal(&c->mf6c_origin, &mfc->mf6cc_origin.sin6_addr) &&
		    ipv6_addr_equal(&c->mf6c_mcastgrp, &mfc->mf6cc_mcastgrp.sin6_addr))
			break;
	}

	if (c != NULL) {
		write_lock_bh(&mrt_lock);
		c->mf6c_parent = mfc->mf6cc_parent;
		ip6mr_update_thresholds(c, ttls);
		if (!mrtsock)
			c->mfc_flags |= MFC_STATIC;
		write_unlock_bh(&mrt_lock);
		return 0;
	}

	if (!ipv6_addr_is_multicast(&mfc->mf6cc_mcastgrp.sin6_addr))
		return -EINVAL;

	c = ip6mr_cache_alloc();
	if (c == NULL)
		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(c, ttls);
	if (!mrtsock)
		c->mfc_flags |= MFC_STATIC;

	write_lock_bh(&mrt_lock);
	c->next = mfc6_cache_array[line];
	mfc6_cache_array[line] = c;
	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.
	 */
	spin_lock_bh(&mfc_unres_lock);
	for (cp = &mfc_unres_queue; (uc = *cp) != NULL;
	     cp = &uc->next) {
		if (ipv6_addr_equal(&uc->mf6c_origin, &c->mf6c_origin) &&
		    ipv6_addr_equal(&uc->mf6c_mcastgrp, &c->mf6c_mcastgrp)) {
			*cp = uc->next;
			if (atomic_dec_and_test(&cache_resolve_queue_len))
				del_timer(&ipmr_expire_timer);
			break;
		}
	}
	spin_unlock_bh(&mfc_unres_lock);

	if (uc) {
		ip6mr_cache_resolve(uc, c);
		kmem_cache_free(mrt_cachep, uc);
	}
	return 0;
}

/*
 *	Close the multicast socket, and clear the vif tables etc
 */

static void mroute_clean_tables(struct sock *sk)
{
	int i;

	/*
	 *	Shut down all active vif entries
	 */
	for (i = 0; i < maxvif; i++) {
		if (!(vif6_table[i].flags & VIFF_STATIC))
			mif6_delete(i);
	}

	/*
	 *	Wipe the cache
	 */
	for (i = 0; i < ARRAY_SIZE(mfc6_cache_array); i++) {
		struct mfc6_cache *c, **cp;

		cp = &mfc6_cache_array[i];
		while ((c = *cp) != NULL) {
			if (c->mfc_flags & MFC_STATIC) {
				cp = &c->next;
				continue;
			}
			write_lock_bh(&mrt_lock);
			*cp = c->next;
			write_unlock_bh(&mrt_lock);

			kmem_cache_free(mrt_cachep, c);
		}
	}

	if (atomic_read(&cache_resolve_queue_len) != 0) {
		struct mfc6_cache *c;

		spin_lock_bh(&mfc_unres_lock);
		while (mfc_unres_queue != NULL) {
			c = mfc_unres_queue;
			mfc_unres_queue = c->next;
			spin_unlock_bh(&mfc_unres_lock);

			ip6mr_destroy_unres(c);

			spin_lock_bh(&mfc_unres_lock);
		}
		spin_unlock_bh(&mfc_unres_lock);
	}
}

static int ip6mr_sk_init(struct sock *sk)
{
	int err = 0;

	rtnl_lock();
	write_lock_bh(&mrt_lock);
	if (likely(mroute6_socket == NULL))
		mroute6_socket = sk;
	else
		err = -EADDRINUSE;
	write_unlock_bh(&mrt_lock);

	rtnl_unlock();

	return err;
}

int ip6mr_sk_done(struct sock *sk)
{
	int err = 0;

	rtnl_lock();
	if (sk == mroute6_socket) {
		write_lock_bh(&mrt_lock);
		mroute6_socket = NULL;
		write_unlock_bh(&mrt_lock);

		mroute_clean_tables(sk);
	} else
		err = -EACCES;
	rtnl_unlock();

	return err;
}

/*
 *	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 ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, int optlen)
{
	int ret;
	struct mif6ctl vif;
	struct mf6cctl mfc;
	mifi_t mifi;

	if (optname != MRT6_INIT) {
		if (sk != mroute6_socket && !capable(CAP_NET_ADMIN))
			return -EACCES;
	}

	switch (optname) {
	case MRT6_INIT:
		if (sk->sk_type != SOCK_RAW ||
		    inet_sk(sk)->num != IPPROTO_ICMPV6)
			return -EOPNOTSUPP;
		if (optlen < sizeof(int))
			return -EINVAL;

		return ip6mr_sk_init(sk);

	case MRT6_DONE:
		return ip6mr_sk_done(sk);

	case MRT6_ADD_MIF:
		if (optlen < sizeof(vif))
			return -EINVAL;
		if (copy_from_user(&vif, optval, sizeof(vif)))
			return -EFAULT;
		if (vif.mif6c_mifi >= MAXVIFS)
			return -ENFILE;
		rtnl_lock();
		ret = mif6_add(&vif, sk == mroute6_socket);
		rtnl_unlock();
		return ret;

	case MRT6_DEL_MIF:
		if (optlen < sizeof(mifi_t))
			return -EINVAL;
		if (copy_from_user(&mifi, optval, sizeof(mifi_t)))
			return -EFAULT;
		rtnl_lock();
		ret = mif6_delete(mifi);
		rtnl_unlock();
		return ret;

	/*
	 *	Manipulate the forwarding caches. These live
	 *	in a sort of kernel/user symbiosis.
	 */
	case MRT6_ADD_MFC:
	case MRT6_DEL_MFC:
		if (optlen < sizeof(mfc))
			return -EINVAL;
		if (copy_from_user(&mfc, optval, sizeof(mfc)))
			return -EFAULT;
		rtnl_lock();
		if (optname == MRT6_DEL_MFC)
			ret = ip6mr_mfc_delete(&mfc);
		else
			ret = ip6mr_mfc_add(&mfc, sk == mroute6_socket);
		rtnl_unlock();
		return ret;

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

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

int ip6_mroute_getsockopt(struct sock *sk, int optname, char __user *optval,
			  int __user *optlen)
{
	int olr;
	int val;

	switch (optname) {
	case MRT6_VERSION:
		val = 0x0305;
		break;
	default:
		return -ENOPROTOOPT;
	}

	if (get_user(olr, optlen))
		return -EFAULT;

	olr = min_t(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 ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
{
	struct sioc_sg_req6 sr;
	struct sioc_mif_req6 vr;
	struct mif_device *vif;
	struct mfc6_cache *c;

	switch (cmd) {
	case SIOCGETMIFCNT_IN6:
		if (copy_from_user(&vr, arg, sizeof(vr)))
			return -EFAULT;
		if (vr.mifi >= maxvif)
			return -EINVAL;
		read_lock(&mrt_lock);
		vif = &vif6_table[vr.mifi];
		if (MIF_EXISTS(vr.mifi)) {
			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_IN6:
		if (copy_from_user(&sr, arg, sizeof(sr)))
			return -EFAULT;

		read_lock(&mrt_lock);
		c = ip6mr_cache_find(&sr.src.sin6_addr, &sr.grp.sin6_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;
			read_unlock(&mrt_lock);

			if (copy_to_user(arg, &sr, sizeof(sr)))
				return -EFAULT;
			return 0;
		}
		read_unlock(&mrt_lock);
		return -EADDRNOTAVAIL;
	default:
		return -ENOIOCTLCMD;
	}
}


static inline int ip6mr_forward2_finish(struct sk_buff *skb)
{
	/* XXX stats */
	return dst_output(skb);
}

/*
 *	Processing handlers for ip6mr_forward
 */

static int ip6mr_forward2(struct sk_buff *skb, struct mfc6_cache *c, int vifi)
{
	struct ipv6hdr *ipv6h;
	struct mif_device *vif = &vif6_table[vifi];
	struct net_device *dev;
	struct dst_entry *dst;
	struct flowi fl;

	if (vif->dev == NULL)
		goto out_free;

	ipv6h = ipv6_hdr(skb);

	fl = (struct flowi) {
		.oif = vif->link,
		.nl_u = { .ip6_u =
				{ .daddr = ipv6h->daddr, }
		}
	};

	dst = ip6_route_output(&init_net, NULL, &fl);
	if (!dst)
		goto out_free;

	dst_release(skb->dst);
	skb->dst = dst;

	/*
	 * 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.
	 */
	dev = vif->dev;
	skb->dev = dev;
	vif->pkt_out++;
	vif->bytes_out += skb->len;

	/* We are about to write */
	/* XXX: extension headers? */
	if (skb_cow(skb, sizeof(*ipv6h) + LL_RESERVED_SPACE(dev)))
		goto out_free;

	ipv6h = ipv6_hdr(skb);
	ipv6h->hop_limit--;

	IP6CB(skb)->flags |= IP6SKB_FORWARDED;

	return NF_HOOK(PF_INET6, NF_INET_FORWARD, skb, skb->dev, dev,
		       ip6mr_forward2_finish);

out_free:
	kfree_skb(skb);
	return 0;
}

static int ip6mr_find_vif(struct net_device *dev)
{
	int ct;
	for (ct = maxvif - 1; ct >= 0; ct--) {
		if (vif6_table[ct].dev == dev)
			break;
	}
	return ct;
}

static int ip6_mr_forward(struct sk_buff *skb, struct mfc6_cache *cache)
{
	int psend = -1;
	int vif, ct;

	vif = cache->mf6c_parent;
	cache->mfc_un.res.pkt++;
	cache->mfc_un.res.bytes += skb->len;

	vif6_table[vif].pkt_in++;
	vif6_table[vif].bytes_in += skb->len;

	/*
	 *	Forward the frame
	 */
	for (ct = cache->mfc_un.res.maxvif - 1; ct >= cache->mfc_un.res.minvif; ct--) {
		if (ipv6_hdr(skb)->hop_limit > cache->mfc_un.res.ttls[ct]) {
			if (psend != -1) {
				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
				if (skb2)
					ip6mr_forward2(skb2, cache, psend);
			}
			psend = ct;
		}
	}
	if (psend != -1) {
		ip6mr_forward2(skb, cache, psend);
		return 0;
	}

	kfree_skb(skb);
	return 0;
}


/*
 *	Multicast packets for forwarding arrive here
 */

int ip6_mr_input(struct sk_buff *skb)
{
	struct mfc6_cache *cache;

	read_lock(&mrt_lock);
	cache = ip6mr_cache_find(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr);

	/*
	 *	No usable cache entry
	 */
	if (cache == NULL) {
		int vif;

		vif = ip6mr_find_vif(skb->dev);
		if (vif >= 0) {
			int err = ip6mr_cache_unresolved(vif, skb);
			read_unlock(&mrt_lock);

			return err;
		}
		read_unlock(&mrt_lock);
		kfree_skb(skb);
		return -ENODEV;
	}

	ip6_mr_forward(skb, cache);

	read_unlock(&mrt_lock);

	return 0;
}


static int
ip6mr_fill_mroute(struct sk_buff *skb, struct mfc6_cache *c, struct rtmsg *rtm)
{
	int ct;
	struct rtnexthop *nhp;
	struct net_device *dev = vif6_table[c->mf6c_parent].dev;
	u8 *b = skb->tail;
	struct rtattr *mp_head;

	if (dev)
		RTA_PUT(skb, RTA_IIF, 4, &dev->ifindex);

	mp_head = (struct rtattr *)skb_put(skb, RTA_LENGTH(0));

	for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
		if (c->mfc_un.res.ttls[ct] < 255) {
			if (skb_tailroom(skb) < RTA_ALIGN(RTA_ALIGN(sizeof(*nhp)) + 4))
				goto rtattr_failure;
			nhp = (struct rtnexthop *)skb_put(skb, RTA_ALIGN(sizeof(*nhp)));
			nhp->rtnh_flags = 0;
			nhp->rtnh_hops = c->mfc_un.res.ttls[ct];
			nhp->rtnh_ifindex = vif6_table[ct].dev->ifindex;
			nhp->rtnh_len = sizeof(*nhp);
		}
	}
	mp_head->rta_type = RTA_MULTIPATH;
	mp_head->rta_len = skb->tail - (u8 *)mp_head;
	rtm->rtm_type = RTN_MULTICAST;
	return 1;

rtattr_failure:
	nlmsg_trim(skb, b);
	return -EMSGSIZE;
}

int ip6mr_get_route(struct sk_buff *skb, struct rtmsg *rtm, int nowait)
{
	int err;
	struct mfc6_cache *cache;
	struct rt6_info *rt = (struct rt6_info *)skb->dst;

	read_lock(&mrt_lock);
	cache = ip6mr_cache_find(&rt->rt6i_src.addr, &rt->rt6i_dst.addr);

	if (!cache) {
		struct sk_buff *skb2;
		struct ipv6hdr *iph;
		struct net_device *dev;
		int vif;

		if (nowait) {
			read_unlock(&mrt_lock);
			return -EAGAIN;
		}

		dev = skb->dev;
		if (dev == NULL || (vif = ip6mr_find_vif(dev)) < 0) {
			read_unlock(&mrt_lock);
			return -ENODEV;
		}

		/* really correct? */
		skb2 = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
		if (!skb2) {
			read_unlock(&mrt_lock);
			return -ENOMEM;
		}

		skb_reset_transport_header(skb2);

		skb_put(skb2, sizeof(struct ipv6hdr));
		skb_reset_network_header(skb2);

		iph = ipv6_hdr(skb2);
		iph->version = 0;
		iph->priority = 0;
		iph->flow_lbl[0] = 0;
		iph->flow_lbl[1] = 0;
		iph->flow_lbl[2] = 0;
		iph->payload_len = 0;
		iph->nexthdr = IPPROTO_NONE;
		iph->hop_limit = 0;
		ipv6_addr_copy(&iph->saddr, &rt->rt6i_src.addr);
		ipv6_addr_copy(&iph->daddr, &rt->rt6i_dst.addr);

		err = ip6mr_cache_unresolved(vif, skb2);
		read_unlock(&mrt_lock);

		return err;
	}

	if (!nowait && (rtm->rtm_flags&RTM_F_NOTIFY))
		cache->mfc_flags |= MFC_NOTIFY;

	err = ip6mr_fill_mroute(skb, cache, rtm);
	read_unlock(&mrt_lock);
	return err;
}