[IPV6] MROUTE: Support multicast forwarding.

Based on ancient patch by Mickael Hoerdt
<hoerdt@clarinet.u-strasbg.fr>, which is available at
<http://www-r2.u-strasbg.fr/~hoerdt/dev/linux_ipv6_mforwarding/patch-linux-ipv6-mforwarding-0.1a>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

1 files changed, 1384 insertions, 0 deletions

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
new file mode 100644
index 0000000..1bdf3c1
--- /dev/null
+++ b/net/ipv6/ip6mr.c
@@ -0,0 +1,1384 @@
+/*
+ *	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;
+}
+