[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>

10 files changed, 1521 insertions, 30 deletions

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index 47263e45bac..9a2ea81e499 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -209,3 +209,10 @@ config IPV6_SUBTREES
 
 	  If unsure, say N.
 
+config IPV6_MROUTE
+	bool "IPv6: multicast routing (EXPERIMENTAL)"
+	depends on IPV6 && EXPERIMENTAL
+	---help---
+	  Experimental support for IPv6 multicast forwarding.
+	  If unsure, say N.
+
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index ae14617e607..686934acfac 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -11,6 +11,8 @@ ipv6-objs :=	af_inet6.o anycast.o ip6_output.o ip6_input.o addrconf.o \
 		exthdrs.o datagram.o ip6_flowlabel.o inet6_connection_sock.o
 
 ipv6-$(CONFIG_SYSCTL) = sysctl_net_ipv6.o
+ipv6-$(CONFIG_IPV6_MROUTE) += ip6mr.o
+
 ipv6-$(CONFIG_XFRM) += xfrm6_policy.o xfrm6_state.o xfrm6_input.o \
 	xfrm6_output.o
 ipv6-$(CONFIG_NETFILTER) += netfilter.o
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 11037615bc7..dbc51af6901 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -412,7 +412,7 @@ static struct inet6_dev * ipv6_add_dev(struct net_device *dev)
 	return ndev;
 }
 
-static struct inet6_dev * ipv6_find_idev(struct net_device *dev)
+struct inet6_dev * ipv6_find_idev(struct net_device *dev)
 {
 	struct inet6_dev *idev;
 
@@ -3547,6 +3547,9 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
 	array[DEVCONF_OPTIMISTIC_DAD] = cnf->optimistic_dad;
 #endif
+#ifdef CONFIG_IPV6_MROUTE
+	array[DEVCONF_MC_FORWARDING] = cnf->mc_forwarding;
+#endif
 }
 
 static inline size_t inet6_if_nlmsg_size(void)
@@ -4095,6 +4098,16 @@ static struct addrconf_sysctl_table
 
 		},
 #endif
+#ifdef CONFIG_IPV6_MROUTE
+		{
+			.ctl_name	=	CTL_UNNUMBERED,
+			.procname	=	"mc_forwarding",
+			.data		=	&ipv6_devconf.mc_forwarding,
+			.maxlen		=	sizeof(int),
+			.mode		=	0644,
+			.proc_handler	=	&proc_dointvec,
+		},
+#endif
 		{
 			.ctl_name	=	0,	/* sentinel */
 		}
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 1731b0abf7f..3c6aafb0218 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -61,6 +61,9 @@
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
+#ifdef CONFIG_IPV6_MROUTE
+#include <linux/mroute6.h>
+#endif
 
 MODULE_AUTHOR("Cast of dozens");
 MODULE_DESCRIPTION("IPv6 protocol stack for Linux");
@@ -953,6 +956,9 @@ static int __init inet6_init(void)
 	err = icmpv6_init();
 	if (err)
 		goto icmp_fail;
+#ifdef CONFIG_IPV6_MROUTE
+	ip6_mr_init();
+#endif
 	err = ndisc_init();
 	if (err)
 		goto ndisc_fail;
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 43a617e2268..09a3201e408 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -29,6 +29,7 @@
 #include <linux/netdevice.h>
 #include <linux/in6.h>
 #include <linux/icmpv6.h>
+#include <linux/mroute6.h>
 
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv6.h>
@@ -236,36 +237,84 @@ int ip6_mc_input(struct sk_buff *skb)
 	hdr = ipv6_hdr(skb);
 	deliver = ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
 
+#ifdef CONFIG_IPV6_MROUTE
 	/*
-	 *	IPv6 multicast router mode isnt currently supported.
+	 *      IPv6 multicast router mode is now supported ;)
 	 */
-#if 0
-	if (ipv6_config.multicast_route) {
-		int addr_type;
-
-		addr_type = ipv6_addr_type(&hdr->daddr);
-
-		if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
-			struct sk_buff *skb2;
-			struct dst_entry *dst;
+	if (ipv6_devconf.mc_forwarding &&
+	    likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
+		/*
+		 * Okay, we try to forward - split and duplicate
+		 * packets.
+		 */
+		struct sk_buff *skb2;
+		struct inet6_skb_parm *opt = IP6CB(skb);
+
+		/* Check for MLD */
+		if (unlikely(opt->ra)) {
+			/* Check if this is a mld message */
+			u8 *ptr = skb_network_header(skb) + opt->ra;
+			struct icmp6hdr *icmp6;
+			u8 nexthdr = hdr->nexthdr;
+			int offset;
+
+			/* Check if the value of Router Alert
+			 * is for MLD (0x0000).
+			 */
+			if ((ptr[2] | ptr[3]) == 0) {
+				if (!ipv6_ext_hdr(nexthdr)) {
+					/* BUG */
+					goto discard;
+				}
+				offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
+							  &nexthdr);
+				if (offset < 0)
+					goto discard;
+
+				if (nexthdr != IPPROTO_ICMPV6)
+					goto discard;
+
+				if (!pskb_may_pull(skb, (skb_network_header(skb) +
+						   offset + 1 - skb->data)))
+					goto discard;
+
+				icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
+
+				switch (icmp6->icmp6_type) {
+				case ICMPV6_MGM_QUERY:
+				case ICMPV6_MGM_REPORT:
+				case ICMPV6_MGM_REDUCTION:
+				case ICMPV6_MLD2_REPORT:
+					break;
+				default:
+					/* Bogus */
+					goto discard;
+				}
+				deliver = 1;
+				goto out;
+			}
+			/* unknown RA - process it normally */
+		}
 
-			dst = skb->dst;
+		if (deliver)
+			skb2 = skb_clone(skb, GFP_ATOMIC);
+		else {
+			skb2 = skb;
+			skb = NULL;
+		}
 
-			if (deliver) {
-				skb2 = skb_clone(skb, GFP_ATOMIC);
-				dst_output(skb2);
-			} else {
-				dst_output(skb);
-				return 0;
-			}
+		if (skb2) {
+			skb2->dev = skb2->dst->dev;
+			ip6_mr_input(skb2);
 		}
 	}
 #endif
-
+out:
 	if (likely(deliver)) {
 		ip6_input(skb);
 		return 0;
 	}
+discard:
 	/* discard */
 	kfree_skb(skb);
 
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index a8b4da25b0a..c0dbe549cc4 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -55,6 +55,7 @@
 #include <net/icmp.h>
 #include <net/xfrm.h>
 #include <net/checksum.h>
+#include <linux/mroute6.h>
 
 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 
@@ -137,8 +138,9 @@ static int ip6_output2(struct sk_buff *skb)
 		struct inet6_dev *idev = ip6_dst_idev(skb->dst);
 
 		if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&
-		    ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
-					&ipv6_hdr(skb)->saddr)) {
+		    ((mroute6_socket && !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
+		     ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
+					 &ipv6_hdr(skb)->saddr))) {
 			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
 
 			/* Do not check for IFF_ALLMULTI; multicast routing
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
new file mode 100644
index 00000000000..1bdf3c177d5
--- /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) {