Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3181 insertions, 0 deletions

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
new file mode 100644
index 0000000000..0063a23725
--- /dev/null
+++ b/net/ipv4/ipmr.c
@@ -0,0 +1,3181 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	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
+ *
+ *	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 <linux/uaccess.h>
+#include <linux/types.h>
+#include <linux/cache.h>
+#include <linux/capability.h>
+#include <linux/errno.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/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 <linux/rhashtable.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/rtnh.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_SPINLOCK(mrt_lock);
+
+static struct net_device *vif_dev_read(const struct vif_device *vif)
+{
+	return rcu_dereference(vif->dev);
+}
+
+/* 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 __ro_after_init;
+
+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 net_device *dev, struct sk_buff *skb,
+			  struct mfc_cache *cache, int local);
+static int ipmr_cache_report(const struct mr_table *mrt,
+			     struct sk_buff *pkt, vifi_t vifi, int assert);
+static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,
+				 int cmd);
+static void igmpmsg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt);
+static void mroute_clean_tables(struct mr_table *mrt, int flags);
+static void ipmr_expire_process(struct timer_list *t);
+
+#ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
+#define ipmr_for_each_table(mrt, net)					\
+	list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list,	\
+				lockdep_rtnl_is_held() ||		\
+				list_empty(&net->ipv4.mr_tables))
+
+static struct mr_table *ipmr_mr_table_iter(struct net *net,
+					   struct mr_table *mrt)
+{
+	struct mr_table *ret;
+
+	if (!mrt)
+		ret = list_entry_rcu(net->ipv4.mr_tables.next,
+				     struct mr_table, list);
+	else
+		ret = list_entry_rcu(mrt->list.next,
+				     struct mr_table, list);
+
+	if (&ret->list == &net->ipv4.mr_tables)
+		return NULL;
+	return ret;
+}
+
+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,
+	};
+
+	/* update flow if oif or iif point to device enslaved to l3mdev */
+	l3mdev_update_flow(net, flowi4_to_flowi(flp4));
+
+	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;
+	}
+
+	arg->table = fib_rule_get_table(rule, arg);
+
+	mrt = ipmr_get_table(rule->fr_net, arg->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 int ipmr_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
+			       struct fib_rule_hdr *frh, struct nlattr **tb,
+			       struct netlink_ext_ack *extack)
+{
+	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,
+	.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:
+	rtnl_lock();
+	ipmr_free_table(mrt);
+	rtnl_unlock();
+err1:
+	fib_rules_unregister(ops);
+	return err;
+}
+
+static void __net_exit ipmr_rules_exit(struct net *net)
+{
+	struct mr_table *mrt, *next;
+
+	ASSERT_RTNL();
+	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);
+}
+
+static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
+			   struct netlink_ext_ack *extack)
+{
+	return fib_rules_dump(net, nb, RTNL_FAMILY_IPMR, extack);
+}
+
+static unsigned int ipmr_rules_seq_read(struct net *net)
+{
+	return fib_rules_seq_read(net, RTNL_FAMILY_IPMR);
+}
+
+bool ipmr_rule_default(const struct fib_rule *rule)
+{
+	return fib_rule_matchall(rule) && rule->table == RT_TABLE_DEFAULT;
+}
+EXPORT_SYMBOL(ipmr_rule_default);
+#else
+#define ipmr_for_each_table(mrt, net) \
+	for (mrt = net->ipv4.mrt; mrt; mrt = NULL)
+
+static struct mr_table *ipmr_mr_table_iter(struct net *net,
+					   struct mr_table *mrt)
+{
+	if (!mrt)
+		return net->ipv4.mrt;
+	return 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)
+{
+	ASSERT_RTNL();
+	ipmr_free_table(net->ipv4.mrt);
+	net->ipv4.mrt = NULL;
+}
+
+static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
+			   struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+static unsigned int ipmr_rules_seq_read(struct net *net)
+{
+	return 0;
+}
+
+bool ipmr_rule_default(const struct fib_rule *rule)
+{
+	return true;
+}
+EXPORT_SYMBOL(ipmr_rule_default);
+#endif
+
+static inline int ipmr_hash_cmp(struct rhashtable_compare_arg *arg,
+				const void *ptr)
+{
+	const struct mfc_cache_cmp_arg *cmparg = arg->key;
+	const struct mfc_cache *c = ptr;
+
+	return cmparg->mfc_mcastgrp != c->mfc_mcastgrp ||
+	       cmparg->mfc_origin != c->mfc_origin;
+}
+
+static const struct rhashtable_params ipmr_rht_params = {
+	.head_offset = offsetof(struct mr_mfc, mnode),
+	.key_offset = offsetof(struct mfc_cache, cmparg),
+	.key_len = sizeof(struct mfc_cache_cmp_arg),
+	.nelem_hint = 3,
+	.obj_cmpfn = ipmr_hash_cmp,
+	.automatic_shrinking = true,
+};
+
+static void ipmr_new_table_set(struct mr_table *mrt,
+			       struct net *net)
+{
+#ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
+	list_add_tail_rcu(&mrt->list, &net->ipv4.mr_tables);
+#endif
+}
+
+static struct mfc_cache_cmp_arg ipmr_mr_table_ops_cmparg_any = {
+	.mfc_mcastgrp = htonl(INADDR_ANY),
+	.mfc_origin = htonl(INADDR_ANY),
+};
+
+static struct mr_table_ops ipmr_mr_table_ops = {
+	.rht_params = &ipmr_rht_params,
+	.cmparg_any = &ipmr_mr_table_ops_cmparg_any,
+};
+
+static struct mr_table *ipmr_new_table(struct net *net, u32 id)
+{
+	struct mr_table *mrt;
+
+	/* "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;
+
+	return mr_table_alloc(net, id, &ipmr_mr_table_ops,
+			      ipmr_expire_process, ipmr_new_table_set);
+}
+
+static void ipmr_free_table(struct mr_table *mrt)
+{
+	timer_shutdown_sync(&mrt->ipmr_expire_timer);
+	mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_VIFS_STATIC |
+				 MRT_FLUSH_MFC | MRT_FLUSH_MFC_STATIC);
+	rhltable_destroy(&mrt->mfc_hash);
+	kfree(mrt);
+}
+
+/* Service routines creating virtual interfaces: DVMRP tunnels and PIMREG */
+
+/* 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 *tunnel_dev, *new_dev;
+	struct ip_tunnel_parm p = { };
+	int err;
+
+	tunnel_dev = __dev_get_by_name(net, "tunl0");
+	if (!tunnel_dev)
+		goto out;
+
+	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);
+
+	if (!tunnel_dev->netdev_ops->ndo_tunnel_ctl)
+		goto out;
+	err = tunnel_dev->netdev_ops->ndo_tunnel_ctl(tunnel_dev, &p,
+			SIOCADDTUNNEL);
+	if (err)
+		goto out;
+
+	new_dev = __dev_get_by_name(net, p.name);
+	if (!new_dev)
+		goto out;
+
+	new_dev->flags |= IFF_MULTICAST;
+	if (!ipmr_init_vif_indev(new_dev))
+		goto out_unregister;
+	if (dev_open(new_dev, NULL))
+		goto out_unregister;
+	dev_hold(new_dev);
+	err = dev_set_allmulti(new_dev, 1);
+	if (err) {
+		dev_close(new_dev);
+		tunnel_dev->netdev_ops->ndo_tunnel_ctl(tunnel_dev, &p,
+				SIOCDELTUNNEL);
+		dev_put(new_dev);
+		new_dev = ERR_PTR(err);
+	}
+	return new_dev;
+
+out_unregister:
+	unregister_netdevice(new_dev);
+out:
+	return ERR_PTR(-ENOBUFS);
+}
+
+#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;
+	}
+
+	DEV_STATS_ADD(dev, tx_bytes, skb->len);
+	DEV_STATS_INC(dev, tx_packets);
+	rcu_read_lock();
+
+	/* Pairs with WRITE_ONCE() in vif_add() and vif_delete() */
+	ipmr_cache_report(mrt, skb, READ_ONCE(mrt->mroute_reg_vif_num),
+			  IGMPMSG_WHOLEPKT);
+
+	rcu_read_unlock();
+	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->needs_free_netdev	= true;
+	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, NULL))
+		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;
+	int vif_num;
+
+	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;
+
+	/* Pairs with WRITE_ONCE() in vif_add()/vid_delete() */
+	vif_num = READ_ONCE(mrt->mroute_reg_vif_num);
+	if (vif_num >= 0)
+		reg_dev = vif_dev_read(&mrt->vif_table[vif_num]);
+	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
+
+static int call_ipmr_vif_entry_notifiers(struct net *net,
+					 enum fib_event_type event_type,
+					 struct vif_device *vif,
+					 struct net_device *vif_dev,
+					 vifi_t vif_index, u32 tb_id)
+{
+	return mr_call_vif_notifiers(net, RTNL_FAMILY_IPMR, event_type,
+				     vif, vif_dev, vif_index, tb_id,
+				     &net->ipv4.ipmr_seq);
+}
+
+static int call_ipmr_mfc_entry_notifiers(struct net *net,
+					 enum fib_event_type event_type,
+					 struct mfc_cache *mfc, u32 tb_id)
+{
+	return mr_call_mfc_notifiers(net, RTNL_FAMILY_IPMR, event_type,
+				     &mfc->_c, tb_id, &net->ipv4.ipmr_seq);
+}
+
+/**
+ *	vif_delete - Delete a VIF entry
+ *	@mrt: Table to delete from
+ *	@vifi: VIF identifier to delete
+ *	@notify: Set to 1, if the caller is a notifier_call
+ *	@head: if unregistering the VIF, place it on this queue
+ */
+static int vif_delete(struct mr_table *mrt, int vifi, int notify,
+		      struct list_head *head)
+{
+	struct net *net = read_pnet(&mrt->net);
+	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];
+
+	dev = rtnl_dereference(v->dev);
+	if (!dev)
+		return -EADDRNOTAVAIL;
+
+	spin_lock(&mrt_lock);
+	call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, dev,
+				      vifi, mrt->id);
+	RCU_INIT_POINTER(v->dev, NULL);
+
+	if (vifi == mrt->mroute_reg_vif_num) {
+		/* Pairs with READ_ONCE() in ipmr_cache_report() and reg_vif_xmit() */
+		WRITE_ONCE(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;
+		}
+		WRITE_ONCE(mrt->maxvif, tmp + 1);
+	}
+
+	spin_unlock(&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), RTM_NEWNETCONF,
+					    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);
+
+	netdev_put(dev, &v->dev_tracker);
+	return 0;
+}
+
+static void ipmr_cache_free_rcu(struct rcu_head *head)
+{
+	struct mr_mfc *c = container_of(head, struct mr_mfc, rcu);
+
+	kmem_cache_free(mrt_cachep, (struct mfc_cache *)c);
+}
+
+static void ipmr_cache_free(struct mfc_cache *c)
+{
+	call_rcu(&c->_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->_c.mfc_un.unres.unresolved))) {
+		if (ip_hdr(skb)->version == 0) {
+			struct nlmsghdr *nlh = 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(struct timer_list *t)
+{
+	struct mr_table *mrt = from_timer(mrt, t, ipmr_expire_timer);
+	struct mr_mfc *c, *next;
+	unsigned long expires;
+	unsigned long now;
+
+	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, (struct mfc_cache *)c, RTM_DELROUTE);
+		ipmr_destroy_unres(mrt, (struct mfc_cache *)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 locked mrt_lock. */
+static void ipmr_update_thresholds(struct mr_table *mrt, struct mr_mfc *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)
+{
+	struct netdev_phys_item_id ppid = { };
+	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 (IS_ERR(dev))
+			return PTR_ERR(dev);
+		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, RTM_NEWNETCONF, NETCONFA_MC_FORWARDING,
+				    dev->ifindex, &in_dev->cnf);
+	ip_rt_multicast_event(in_dev);
+
+	/* Fill in the VIF structures */
+	vif_device_init(v, dev, vifc->vifc_rate_limit,
+			vifc->vifc_threshold,
+			vifc->vifc_flags | (!mrtsock ? VIFF_STATIC : 0),
+			(VIFF_TUNNEL | VIFF_REGISTER));
+
+	err = dev_get_port_parent_id(dev, &ppid, true);
+	if (err == 0) {
+		memcpy(v->dev_parent_id.id, ppid.id, ppid.id_len);
+		v->dev_parent_id.id_len = ppid.id_len;
+	} else {
+		v->dev_parent_id.id_len = 0;
+	}
+
+	v->local = vifc->vifc_lcl_addr.s_addr;
+	v->remote = vifc->vifc_rmt_addr.s_addr;
+
+	/* And finish update writing critical data */
+	spin_lock(&mrt_lock);
+	rcu_assign_pointer(v->dev, dev);
+	netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC);
+	if (v->flags & VIFF_REGISTER) {
+		/* Pairs with READ_ONCE() in ipmr_cache_report() and reg_vif_xmit() */
+		WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);
+	}
+	if (vifi+1 > mrt->maxvif)
+		WRITE_ONCE(mrt->maxvif, vifi + 1);
+	spin_unlock(&mrt_lock);
+	call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev,
+				      vifi, mrt->id);
+	return 0;
+}
+
+/* called with rcu_read_lock() */
+static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt,
+					 __be32 origin,
+					 __be32 mcastgrp)
+{
+	struct mfc_cache_cmp_arg arg = {
+			.mfc_mcastgrp = mcastgrp,
+			.mfc_origin = origin
+	};
+
+	return mr_mfc_find(mrt, &arg);
+}
+
+/* Look for a (*,G) entry */
+static struct mfc_cache *ipmr_cache_find_any(struct mr_table *mrt,
+					     __be32 mcastgrp, int vifi)
+{
+	struct mfc_cache_cmp_arg arg = {
+			.mfc_mcastgrp = mcastgrp,
+			.mfc_origin = htonl(INADDR_ANY)
+	};
+
+	if (mcastgrp == htonl(INADDR_ANY))
+		return mr_mfc_find_any_parent(mrt, vifi);
+	return mr_mfc_find_any(mrt, vifi, &arg);
+}
+
+/* Look for a (S,G,iif) entry if parent != -1 */
+static struct mfc_cache *ipmr_cache_find_parent(struct mr_table *mrt,
+						__be32 origin, __be32 mcastgrp,
+						int parent)
+{
+	struct mfc_cache_cmp_arg arg = {
+			.mfc_mcastgrp = mcastgrp,
+			.mfc_origin = origin,
+	};
+
+	return mr_mfc_find_parent(mrt, &arg, parent);
+}
+
+/* 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->_c.mfc_un.res.last_assert = jiffies - MFC_ASSERT_THRESH - 1;
+		c->_c.mfc_un.res.minvif = MAXVIFS;
+		c->_c.free = ipmr_cache_free_rcu;
+		refcount_set(&c->_c.mfc_un.res.refcount, 1);
+	}
+	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->_c.mfc_un.unres.unresolved);
+		c->_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->_c.mfc_un.unres.unresolved))) {
+		if (ip_hdr(skb)->version == 0) {
+			struct nlmsghdr *nlh = skb_pull(skb,
+							sizeof(struct iphdr));
+
+			if (mr_fill_mroute(mrt, skb, &c->_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 {
+			rcu_read_lock();
+			ip_mr_forward(net, mrt, skb->dev, skb, c, 0);
+			rcu_read_unlock();
+		}
+	}
+}
+
+/* Bounce a cache query up to mrouted and netlink.
+ *
+ * Called under rcu_read_lock().
+ */
+static int ipmr_cache_report(const 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;
+
+	mroute_sk = rcu_dereference(mrt->mroute_sk);
+	if (!mroute_sk)
+		return -EINVAL;
+
+	if (assert == IGMPMSG_WHOLEPKT || assert == IGMPMSG_WRVIFWHOLE)
+		skb = skb_realloc_headroom(pkt, sizeof(struct iphdr));
+	else
+		skb = alloc_skb(128, GFP_ATOMIC);
+
+	if (!skb)
+		return -ENOBUFS;
+
+	if (assert == IGMPMSG_WHOLEPKT || assert == IGMPMSG_WRVIFWHOLE) {
+		/* 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 = assert;
+		msg->im_mbz = 0;
+		if (assert == IGMPMSG_WRVIFWHOLE) {
+			msg->im_vif = vifi;
+			msg->im_vif_hi = vifi >> 8;
+		} else {
+			/* Pairs with WRITE_ONCE() in vif_add() and vif_delete() */
+			int vif_num = READ_ONCE(mrt->mroute_reg_vif_num);
+
+			msg->im_vif = vif_num;
+			msg->im_vif_hi = vif_num >> 8;
+		}
+		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;
+		msg->im_vif_hi = vifi >> 8;
+		ipv4_pktinfo_prepare(mroute_sk, pkt);
+		memcpy(skb->cb, pkt->cb, sizeof(skb->cb));
+		/* Add our header */
+		igmp = 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;
+	}
+
+	igmpmsg_netlink_event(mrt, skb);
+
+	/* Deliver to mrouted */
+	ret = sock_queue_rcv_skb(mroute_sk, skb);
+
+	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! */
+/* Called under rcu_read_lock() */
+static int ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi,
+				 struct sk_buff *skb, struct net_device *dev)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	struct mfc_cache *c;
+	bool found = false;
+	int err;
+
+	spin_lock_bh(&mfc_unres_lock);
+	list_for_each_entry(c, &mrt->mfc_unres_queue, _c.list) {
+		if (c->mfc_mcastgrp == iph->daddr &&
+		    c->mfc_origin == iph->saddr) {
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		/* Create a new entry if allowable */
+		c = ipmr_cache_alloc_unres();
+		if (!c) {
+			spin_unlock_bh(&mfc_unres_lock);
+
+			kfree_skb(skb);
+			return -ENOBUFS;
+		}
+
+		/* Fill in the new cache entry */
+		c->_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->_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->_c.mfc_un.unres.expires);
+	}
+
+	/* See if we can append the packet */
+	if (c->_c.mfc_un.unres.unresolved.qlen > 3) {
+		kfree_skb(skb);
+		err = -ENOBUFS;
+	} else {
+		if (dev) {
+			skb->dev = dev;
+			skb->skb_iif = dev->ifindex;
+		}
+		skb_queue_tail(&c->_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)
+{
+	struct net *net = read_pnet(&mrt->net);
+	struct mfc_cache *c;
+
+	/* The entries are added/deleted only under RTNL */
+	rcu_read_lock();
+	c = ipmr_cache_find_parent(mrt, mfc->mfcc_origin.s_addr,
+				   mfc->mfcc_mcastgrp.s_addr, parent);
+	rcu_read_unlock();
+	if (!c)
+		return -ENOENT;
+	rhltable_remove(&mrt->mfc_hash, &c->_c.mnode, ipmr_rht_params);
+	list_del_rcu(&c->_c.list);
+	call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, c, mrt->id);
+	mroute_netlink_event(mrt, c, RTM_DELROUTE);
+	mr_cache_put(&c->_c);
+
+	return 0;
+}
+
+static int ipmr_mfc_add(struct net *net, struct mr_table *mrt,
+			struct mfcctl *mfc, int mrtsock, int parent)
+{
+	struct mfc_cache *uc, *c;
+	struct mr_mfc *_uc;
+	bool found;
+	int ret;
+
+	if (mfc->mfcc_parent >= MAXVIFS)
+		return -ENFILE;
+
+	/* The entries are added/deleted only under RTNL */
+	rcu_read_lock();
+	c = ipmr_cache_find_parent(mrt, mfc->mfcc_origin.s_addr,
+				   mfc->mfcc_mcastgrp.s_addr, parent);
+	rcu_read_unlock();
+	if (c) {
+		spin_lock(&mrt_lock);
+		c->_c.mfc_parent = mfc->mfcc_parent;
+		ipmr_update_thresholds(mrt, &c->_c, mfc->mfcc_ttls);
+		if (!mrtsock)
+			c->_c.mfc_flags |= MFC_STATIC;
+		spin_unlock(&mrt_lock);
+		call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE, c,
+					      mrt->id);
+		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->_c.mfc_parent = mfc->mfcc_parent;
+	ipmr_update_thresholds(mrt, &c->_c, mfc->mfcc_ttls);
+	if (!mrtsock)
+		c->_c.mfc_flags |= MFC_STATIC;
+
+	ret = rhltable_insert_key(&mrt->mfc_hash, &c->cmparg, &c->_c.mnode,
+				  ipmr_rht_params);
+	if (ret) {
+		pr_err("ipmr: rhtable insert error %d\n", ret);
+		ipmr_cache_free(c);
+		return ret;
+	}
+	list_add_tail_rcu(&c->_c.list, &mrt->mfc_cache_list);
+	/* 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) {
+		uc = (struct mfc_cache *)_uc;
+		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);
+	}
+	call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_ADD, c, mrt->id);
+	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, int flags)
+{
+	struct net *net = read_pnet(&mrt->net);
+	struct mr_mfc *c, *tmp;
+	struct mfc_cache *cache;
+	LIST_HEAD(list);
+	int i;
+
+	/* Shut down all active vif entries */
+	if (flags & (MRT_FLUSH_VIFS | MRT_FLUSH_VIFS_STATIC)) {
+		for (i = 0; i < mrt->maxvif; i++) {
+			if (((mrt->vif_table[i].flags & VIFF_STATIC) &&
+			     !(flags & MRT_FLUSH_VIFS_STATIC)) ||
+			    (!(mrt->vif_table[i].flags & VIFF_STATIC) && !(flags & MRT_FLUSH_VIFS)))
+				continue;
+			vif_delete(mrt, i, 0, &list);
+		}
+		unregister_netdevice_many(&list);
+	}
+
+	/* Wipe the cache */
+	if (flags & (MRT_FLUSH_MFC | MRT_FLUSH_MFC_STATIC)) {
+		list_for_each_entry_safe(c, tmp, &mrt->mfc_cache_list, list) {
+			if (((c->mfc_flags & MFC_STATIC) && !(flags & MRT_FLUSH_MFC_STATIC)) ||
+			    (!(c->mfc_flags & MFC_STATIC) && !(flags & MRT_FLUSH_MFC)))
+				continue;
+			rhltable_remove(&mrt->mfc_hash, &c->mnode, ipmr_rht_params);
+			list_del_rcu(&c->list);
+			cache = (struct mfc_cache *)c;
+			call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, cache,
+						      mrt->id);
+			mroute_netlink_event(mrt, cache, RTM_DELROUTE);
+			mr_cache_put(c);
+		}
+	}
+
+	if (flags & MRT_FLUSH_MFC) {
+		if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {
+			spin_lock_bh(&mfc_unres_lock);
+			list_for_each_entry_safe(c, tmp, &mrt->mfc_unres_queue, list) {
+				list_del(&c->list);
+				cache = (struct mfc_cache *)c;
+				mroute_netlink_event(mrt, cache, RTM_DELROUTE);
+				ipmr_destroy_unres(mrt, cache);
+			}
+			spin_unlock_bh(&mfc_unres_lock);
+		}
+	}
+}
+
+/* called from ip_ra_control(), before an RCU grace period,
+ * we don't 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, RTM_NEWNETCONF,
+						    NETCONFA_MC_FORWARDING,
+						    NETCONFA_IFINDEX_ALL,
+						    net->ipv4.devconf_all);
+			RCU_INIT_POINTER(mrt->mroute_sk, NULL);
+			mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_MFC);
+		}
+	}
+	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, sockptr_t 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;
+	bool do_wrvifwhole;
+	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, RTM_NEWNETCONF,
+						    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_sockptr(&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;
+		fallthrough;
+	case MRT_ADD_MFC_PROXY:
+	case MRT_DEL_MFC_PROXY:
+		if (optlen != sizeof(mfc)) {
+			ret = -EINVAL;
+			break;
+		}
+		if (copy_from_sockptr(&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;
+	case MRT_FLUSH:
+		if (optlen != sizeof(val)) {
+			ret = -EINVAL;
+			break;
+		}
+		if (copy_from_sockptr(&val, optval, sizeof(val))) {
+			ret = -EFAULT;
+			break;
+		}
+		mroute_clean_tables(mrt, val);
+		break;
+	/* Control PIM assert. */
+	case MRT_ASSERT:
+		if (optlen != sizeof(val)) {
+			ret = -EINVAL;
+			break;
+		}
+		if (copy_from_sockptr(&val, optval, sizeof(val))) {
+			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 (copy_from_sockptr(&val, optval, sizeof(val))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		do_wrvifwhole = (val == IGMPMSG_WRVIFWHOLE);
+		val = !!val;
+		if (val != mrt->mroute_do_pim) {
+			mrt->mroute_do_pim = val;
+			mrt->mroute_do_assert = val;
+			mrt->mroute_do_wrvifwhole = do_wrvifwhole;
+		}
+		break;
+	case MRT_TABLE:
+		if (!IS_BUILTIN(CONFIG_IP_MROUTE_MULTIPLE_TABLES)) {
+			ret = -ENOPROTOOPT;
+			break;
+		}
+		if (optlen != sizeof(uval)) {
+			ret = -EINVAL;
+			break;
+		}
+		if (copy_from_sockptr(&uval, optval, sizeof(uval))) {
+			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;
+}
+
+/* Execute if this ioctl is a special mroute ioctl */
+int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	switch (cmd) {
+	/* These userspace buffers will be consumed by ipmr_ioctl() */
+	case SIOCGETVIFCNT: {
+		struct sioc_vif_req buffer;
+
+		return sock_ioctl_inout(sk, cmd, arg, &buffer,
+				      sizeof(buffer));
+		}
+	case SIOCGETSGCNT: {
+		struct sioc_sg_req buffer;
+
+		return sock_ioctl_inout(sk, cmd, arg, &buffer,
+				      sizeof(buffer));
+		}
+	}
+	/* return code > 0 means that the ioctl was not executed */
+	return 1;
+}
+
+/* Getsock opt support for the multicast routing system. */
+int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
+			 sockptr_t 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 (copy_from_sockptr(&olr, optlen, sizeof(int)))
+		return -EFAULT;
+	olr = min_t(unsigned int, olr, sizeof(int));
+	if (olr < 0)
+		return -EINVAL;
+	if (copy_to_sockptr(optlen, &olr, sizeof(int)))
+		return -EFAULT;
+	if (copy_to_sockptr(optval, &val, olr))
+		return -EFAULT;
+	return 0;
+}
+
+/* The IP multicast ioctl support routines. */
+int ipmr_ioctl(struct sock *sk, int cmd, void *arg)
+{
+	struct vif_device *vif;
+	struct mfc_cache *c;
+	struct net *net = sock_net(sk);
+	struct sioc_vif_req *vr;
+	struct sioc_sg_req *sr;
+	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:
+		vr = (struct sioc_vif_req *)arg;
+		if (vr->vifi >= mrt->maxvif)
+			return -EINVAL;
+		vr->vifi = array_index_nospec(vr->vifi, mrt->maxvif);
+		rcu_read_lock();
+		vif = &mrt->vif_table[vr->vifi];
+		if (VIF_EXISTS(mrt, vr->vifi)) {
+			vr->icount = READ_ONCE(vif->pkt_in);
+			vr->ocount = READ_ONCE(vif->pkt_out);
+			vr->ibytes = READ_ONCE(vif->bytes_in);
+			vr->obytes = READ_ONCE(vif->bytes_out);
+			rcu_read_unlock();
+
+			return 0;
+		}
+		rcu_read_unlock();
+		return -EADDRNOTAVAIL;
+	case SIOCGETSGCNT:
+		sr = (struct sioc_sg_req *)arg;
+
+		rcu_read_lock();
+		c = ipmr_cache_find(mrt, sr->src.s_addr, sr->grp.s_addr);
+		if (c) {
+			sr->pktcnt = c->_c.mfc_un.res.pkt;
+			sr->bytecnt = c->_c.mfc_un.res.bytes;
+			sr->wrong_if = c->_c.mfc_un.res.wrong_if;
+			rcu_read_unlock();
+			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);
+		rcu_read_lock();
+		vif = &mrt->vif_table[vr.vifi];
+		if (VIF_EXISTS(mrt, vr.vifi)) {
+			vr.icount = READ_ONCE(vif->pkt_in);
+			vr.ocount = READ_ONCE(vif->pkt_out);
+			vr.ibytes = READ_ONCE(vif->bytes_in);
+			vr.obytes = READ_ONCE(vif->bytes_out);
+			rcu_read_unlock();
+
+			if (copy_to_user(arg, &vr, sizeof(vr)))
+				return -EFAULT;
+			return 0;
+		}
+		rcu_read_unlock();
+		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->_c.mfc_un.res.pkt;
+			sr.bytecnt = c->_c.mfc_un.res.bytes;
+			sr.wrong_if = c->_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 (rcu_access_pointer(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_ct(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);
+
+	if (unlikely(opt->optlen))
+		ip_forward_options(skb);
+
+	return dst_output(net, sk, skb);
+}
+
+#ifdef CONFIG_NET_SWITCHDEV
+static bool ipmr_forward_offloaded(struct sk_buff *skb, struct mr_table *mrt,
+				   int in_vifi, int out_vifi)
+{
+	struct vif_device *out_vif = &mrt->vif_table[out_vifi];
+	struct vif_device *in_vif = &mrt->vif_table[in_vifi];
+
+	if (!skb->offload_l3_fwd_mark)
+		return false;
+	if (!out_vif->dev_parent_id.id_len || !in_vif->dev_parent_id.id_len)
+		return false;
+	return netdev_phys_item_id_same(&out_vif->dev_parent_id,
+					&in_vif->dev_parent_id);
+}
+#else
+static bool ipmr_forward_offloaded(struct sk_buff *skb, struct mr_table *mrt,
+				   int in_vifi, int out_vifi)
+{
+	return false;
+}
+#endif
+
+/* Processing handlers for ipmr_forward, under rcu_read_lock() */
+
+static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
+			    int in_vifi, struct sk_buff *skb, int vifi)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	struct vif_device *vif = &mrt->vif_table[vifi];
+	struct net_device *vif_dev;
+	struct net_device *dev;
+	struct rtable *rt;
+	struct flowi4 fl4;
+	int    encap = 0;
+
+	vif_dev = vif_dev_read(vif);
+	if (!vif_dev)
+		goto out_free;
+
+	if (vif->flags & VIFF_REGISTER) {
+		WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
+		WRITE_ONCE(vif->bytes_out, vif->bytes_out + skb->len);
+		DEV_STATS_ADD(vif_dev, tx_bytes, skb->len);
+		DEV_STATS_INC(vif_dev, tx_packets);
+		ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);
+		goto out_free;
+	}
+
+	if (ipmr_forward_offloaded(skb, mrt, in_vifi, vifi))
+		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;
+	}
+
+	WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
+	WRITE_ONCE(vif->bytes_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 */
+		DEV_STATS_INC(vif_dev, tx_packets);
+		DEV_STATS_ADD(vif_dev, 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);
+}
+
+/* Called with mrt_lock or rcu_read_lock() */
+static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev)
+{
+	int ct;
+	/* Pairs with WRITE_ONCE() in vif_delete()/vif_add() */
+	for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) {
+		if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)
+			break;
+	}
+	return ct;
+}
+
+/* "local" means that we should preserve one skb (for local delivery) */
+/* Called uner rcu_read_lock() */
+static void ip_mr_forward(struct net *net, struct mr_table *mrt,
+			  struct net_device *dev, struct sk_buff *skb,
+			  struct mfc_cache *c, int local)
+{
+	int true_vifi = ipmr_find_vif(mrt, dev);
+	int psend = -1;
+	int vif, ct;
+
+	vif = c->_c.mfc_parent;
+	c->_c.mfc_un.res.pkt++;
+	c->_c.mfc_un.res.bytes += skb->len;
+	c->_c.mfc_un.res.lastuse = jiffies;
+
+	if (c->mfc_origin == htonl(INADDR_ANY) && true_vifi >= 0) {
+		struct mfc_cache *cache_proxy;
+
+		/* For an (*,G) entry, we only check that the incoming
+		 * interface is part of the static tree.
+		 */
+		cache_proxy = mr_mfc_find_any_parent(mrt, vif);
+		if (cache_proxy &&
+		    cache_proxy->_c.mfc_un.res.ttls[true_vifi] < 255)
+			goto forward;
+	}
+
+	/* Wrong interface: drop packet and (maybe) send PIM assert. */
+	if (rcu_access_pointer(mrt->vif_table[vif].dev) != 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;
+		}
+
+		c->_c.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 ||
+		     c->_c.mfc_un.res.ttls[true_vifi] < 255) &&
+		    time_after(jiffies,
+			       c->_c.mfc_un.res.last_assert +
+			       MFC_ASSERT_THRESH)) {
+			c->_c.mfc_un.res.last_assert = jiffies;
+			ipmr_cache_report(mrt, skb, true_vifi, IGMPMSG_WRONGVIF);
+			if (mrt->mroute_do_wrvifwhole)
+				ipmr_cache_report(mrt, skb, true_vifi,
+						  IGMPMSG_WRVIFWHOLE);
+		}
+		goto dont_forward;
+	}
+
+forward:
+	WRITE_ONCE(mrt->vif_table[vif].pkt_in,
+		   mrt->vif_table[vif].pkt_in + 1);
+	WRITE_ONCE(mrt->vif_table[vif].bytes_in,
+		   mrt->vif_table[vif].bytes_in + skb->len);
+
+	/* Forward the frame */
+	if (c->mfc_origin == htonl(INADDR_ANY) &&
+	    c->mfc_mcastgrp == htonl(INADDR_ANY)) {
+		if (true_vifi >= 0 &&
+		    true_vifi != c->_c.mfc_parent &&
+		    ip_hdr(skb)->ttl >
+				c->_c.mfc_un.res.ttls[c->_c.mfc_parent]) {
+			/* It's an (*,*) entry and the packet is not coming from
+			 * the upstream: forward the packet to the upstream
+			 * only.
+			 */
+			psend = c->_c.mfc_parent;
+			goto last_forward;
+		}
+		goto dont_forward;
+	}
+	for (ct = c->_c.mfc_un.res.maxvif - 1;
+	     ct >= c->_c.mfc_un.res.minvif; ct--) {
+		/* For (*,G) entry, don't forward to the incoming interface */
+		if ((c->mfc_origin != htonl(INADDR_ANY) ||
+		     ct != true_vifi) &&
+		    ip_hdr(skb)->ttl > c->_c.mfc_un.res.ttls[ct]) {
+			if (psend != -1) {
+				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
+				if (skb2)
+					ipmr_queue_xmit(net, mrt, true_vifi,
+							skb2, 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, true_vifi, skb2,
+						psend);
+		} else {
+			ipmr_queue_xmit(net, mrt, true_vifi, skb, 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_ct(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;
+		}
+
+		vif = ipmr_find_vif(mrt, dev);
+		if (vif >= 0)
+			return ipmr_cache_unresolved(mrt, vif, skb, dev);
+		kfree_skb(skb);
+		return -ENODEV;
+	}
+
+	ip_mr_forward(net, mrt, dev, skb, cache, local);
+
+	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_TYPE_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
+
+int ipmr_get_route(struct net *net, struct sk_buff *skb,
+		   __be32 saddr, __be32 daddr,
+		   struct rtmsg *rtm, 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;
+
+		dev = skb->dev;
+		if (dev)
+			vif = ipmr_find_vif(mrt, dev);
+		if (vif < 0) {
+			rcu_read_unlock();
+			return -ENODEV;
+		}
+
+		skb2 = skb_realloc_headroom(skb, sizeof(struct iphdr));
+		if (!skb2) {
+			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, dev);
+		rcu_read_unlock();
+		return err;
+	}
+
+	err = mr_fill_mroute(mrt, skb, &cache->_c, rtm);
+	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->_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 = mr_fill_mroute(mrt, skb, &c->_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 int _ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
+			     u32 portid, u32 seq, struct mr_mfc *c, int cmd,
+			     int flags)
+{
+	return ipmr_fill_mroute(mrt, skb, portid, seq, (struct mfc_cache *)c,
+				cmd, flags);
+}
+
+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->_c.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 size_t igmpmsg_netlink_msgsize(size_t payloadlen)
+{
+	size_t len =
+		NLMSG_ALIGN(sizeof(struct rtgenmsg))
+		+ nla_total_size(1)	/* IPMRA_CREPORT_MSGTYPE */
+		+ nla_total_size(4)	/* IPMRA_CREPORT_VIF_ID */
+		+ nla_total_size(4)	/* IPMRA_CREPORT_SRC_ADDR */
+		+ nla_total_size(4)	/* IPMRA_CREPORT_DST_ADDR */
+		+ nla_total_size(4)	/* IPMRA_CREPORT_TABLE */
+					/* IPMRA_CREPORT_PKT */
+		+ nla_total_size(payloadlen)
+		;
+
+	return len;
+}
+
+static void igmpmsg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt)
+{
+	struct net *net = read_pnet(&mrt->net);
+	struct nlmsghdr *nlh;
+	struct rtgenmsg *rtgenm;
+	struct igmpmsg *msg;
+	struct sk_buff *skb;
+	struct nlattr *nla;
+	int payloadlen;
+
+	payloadlen = pkt->len - sizeof(struct igmpmsg);
+	msg = (struct igmpmsg *)skb_network_header(pkt);
+
+	skb = nlmsg_new(igmpmsg_netlink_msgsize(payloadlen), GFP_ATOMIC);
+	if (!skb)
+		goto errout;
+
+	nlh = nlmsg_put(skb, 0, 0, RTM_NEWCACHEREPORT,
+			sizeof(struct rtgenmsg), 0);
+	if (!nlh)
+		goto errout;
+	rtgenm = nlmsg_data(nlh);
+	rtgenm->rtgen_family = RTNL_FAMILY_IPMR;
+	if (nla_put_u8(skb, IPMRA_CREPORT_MSGTYPE, msg->im_msgtype) ||
+	    nla_put_u32(skb, IPMRA_CREPORT_VIF_ID, msg->im_vif | (msg->im_vif_hi << 8)) ||
+	    nla_put_in_addr(skb, IPMRA_CREPORT_SRC_ADDR,
+			    msg->im_src.s_addr) ||
+	    nla_put_in_addr(skb, IPMRA_CREPORT_DST_ADDR,
+			    msg->im_dst.s_addr) ||
+	    nla_put_u32(skb, IPMRA_CREPORT_TABLE, mrt->id))
+		goto nla_put_failure;
+
+	nla = nla_reserve(skb, IPMRA_CREPORT_PKT, payloadlen);
+	if (!nla || skb_copy_bits(pkt, sizeof(struct igmpmsg),
+				  nla_data(nla), payloadlen))
+		goto nla_put_failure;
+
+	nlmsg_end(skb, nlh);
+
+	rtnl_notify(skb, net, 0, RTNLGRP_IPV4_MROUTE_R, NULL, GFP_ATOMIC);
+	return;
+
+nla_put_failure:
+	nlmsg_cancel(skb, nlh);
+errout:
+	kfree_skb(skb);
+	rtnl_set_sk_err(net, RTNLGRP_IPV4_MROUTE_R, -ENOBUFS);
+}
+
+static int ipmr_rtm_valid_getroute_req(struct sk_buff *skb,
+				       const struct nlmsghdr *nlh,
+				       struct nlattr **tb,
+				       struct netlink_ext_ack *extack)
+{
+	struct rtmsg *rtm;
+	int i, err;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
+		NL_SET_ERR_MSG(extack, "ipv4: Invalid header for multicast route get request");
+		return -EINVAL;
+	}
+
+	if (!netlink_strict_get_check(skb))
+		return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
+					      rtm_ipv4_policy, extack);
+
+	rtm = nlmsg_data(nlh);
+	if ((rtm->rtm_src_len && rtm->rtm_src_len != 32) ||
+	    (rtm->rtm_dst_len && rtm->rtm_dst_len != 32) ||
+	    rtm->rtm_tos || rtm->rtm_table || rtm->rtm_protocol ||
+	    rtm->rtm_scope || rtm->rtm_type || rtm->rtm_flags) {
+		NL_SET_ERR_MSG(extack, "ipv4: Invalid values in header for multicast route get request");
+		return -EINVAL;
+	}
+
+	err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
+					    rtm_ipv4_policy, extack);
+	if (err)
+		return err;
+
+	if ((tb[RTA_SRC] && !rtm->rtm_src_len) ||
+	    (tb[RTA_DST] && !rtm->rtm_dst_len)) {
+		NL_SET_ERR_MSG(extack, "ipv4: rtm_src_len and rtm_dst_len must be 32 for IPv4");
+		return -EINVAL;
+	}
+
+	for (i = 0; i <= RTA_MAX; i++) {
+		if (!tb[i])
+			continue;
+
+		switch (i) {
+		case RTA_SRC:
+		case RTA_DST:
+		case RTA_TABLE:
+			break;
+		default:
+			NL_SET_ERR_MSG(extack, "ipv4: Unsupported attribute in multicast route get request");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int ipmr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+			     struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(in_skb->sk);
+	struct nlattr *tb[RTA_MAX + 1];
+	struct sk_buff *skb = NULL;
+	struct mfc_cache *cache;
+	struct mr_table *mrt;
+	__be32 src, grp;
+	u32 tableid;
+	int err;
+
+	err = ipmr_rtm_valid_getroute_req(in_skb, nlh, tb, extack);
+	if (err < 0)
+		goto errout;
+
+	src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;
+	grp = tb[RTA_DST] ? nla_get_in_addr(tb[RTA_DST]) : 0;
+	tableid = tb[RTA_TABLE] ? nla_get_u32(tb[RTA_TABLE]) : 0;
+
+	mrt = ipmr_get_table(net, tableid ? tableid : RT_TABLE_DEFAULT);
+	if (!mrt) {
+		err = -ENOENT;
+		goto errout_free;
+	}
+
+	/* entries are added/deleted only under RTNL */
+	rcu_read_lock();
+	cache = ipmr_cache_find(mrt, src, grp);
+	rcu_read_unlock();
+	if (!cache) {
+		err = -ENOENT;
+		goto errout_free;
+	}
+
+	skb = nlmsg_new(mroute_msgsize(false, mrt->maxvif), GFP_KERNEL);
+	if (!skb) {
+		err = -ENOBUFS;
+		goto errout_free;
+	}
+
+	err = ipmr_fill_mroute(mrt, skb, NETLINK_CB(in_skb).portid,
+			       nlh->nlmsg_seq, cache,
+			       RTM_NEWROUTE, 0);
+	if (err < 0)
+		goto errout_free;
+
+	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
+
+errout:
+	return err;
+
+errout_free:
+	kfree_skb(skb);
+	goto errout;
+}
+
+static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct fib_dump_filter filter = {};
+	int err;
+
+	if (cb->strict_check) {
+		err = ip_valid_fib_dump_req(sock_net(skb->sk), cb->nlh,
+					    &filter, cb);
+		if (err < 0)
+			return err;
+	}
+
+	if (filter.table_id) {
+		struct mr_table *mrt;
+
+		mrt = ipmr_get_table(sock_net(skb->sk), filter.table_id);
+		if (!mrt) {
+			if (rtnl_msg_family(cb->nlh) != RTNL_FAMILY_IPMR)
+				return skb->len;
+
+			NL_SET_ERR_MSG(cb->extack, "ipv4: MR table does not exist");
+			return -ENOENT;
+		}
+		err = mr_table_dump(mrt, skb, cb, _ipmr_fill_mroute,
+				    &mfc_unres_lock, &filter);
+		return skb->len ? : err;
+	}
+
+	return mr_rtm_dumproute(skb, cb, ipmr_mr_table_iter,
+				_ipmr_fill_mroute, &mfc_unres_lock, &filter);
+}
+
+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 netlink_ext_ack *extack)
+{
+	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_deprecated(nlh, sizeof(*rtm), RTA_MAX,
+					rtm_ipmr_policy, extack);
+	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 netlink_ext_ack *extack)
+{
+	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, extack);
+	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);
+}
+
+static bool ipmr_fill_table(struct mr_table *mrt, struct sk_buff *skb)
+{
+	u32 queue_len = atomic_read(&mrt->cache_resolve_queue_len);
+
+	if (nla_put_u32(skb, IPMRA_TABLE_ID, mrt->id) ||
+	    nla_put_u32(skb, IPMRA_TABLE_CACHE_RES_QUEUE_LEN, queue_len) ||
+	    nla_put_s32(skb, IPMRA_TABLE_MROUTE_REG_VIF_NUM,
+			mrt->mroute_reg_vif_num) ||
+	    nla_put_u8(skb, IPMRA_TABLE_MROUTE_DO_ASSERT,
+		       mrt->mroute_do_assert) ||
+	    nla_put_u8(skb, IPMRA_TABLE_MROUTE_DO_PIM, mrt->mroute_do_pim) ||
+	    nla_put_u8(skb, IPMRA_TABLE_MROUTE_DO_WRVIFWHOLE,
+		       mrt->mroute_do_wrvifwhole))
+		return false;
+
+	return true;
+}
+
+static bool ipmr_fill_vif(struct mr_table *mrt, u32 vifid, struct sk_buff *skb)
+{
+	struct net_device *vif_dev;
+	struct nlattr *vif_nest;
+	struct vif_device *vif;
+
+	vif = &mrt->vif_table[vifid];
+	vif_dev = rtnl_dereference(vif->dev);
+	/* if the VIF doesn't exist just continue */
+	if (!vif_dev)
+		return true;
+
+	vif_nest = nla_nest_start_noflag(skb, IPMRA_VIF);
+	if (!vif_nest)
+		return false;
+
+	if (nla_put_u32(skb, IPMRA_VIFA_IFINDEX, vif_dev->ifindex) ||
+	    nla_put_u32(skb, IPMRA_VIFA_VIF_ID, vifid) ||
+	    nla_put_u16(skb, IPMRA_VIFA_FLAGS, vif->flags) ||
+	    nla_put_u64_64bit(skb, IPMRA_VIFA_BYTES_IN, vif->bytes_in,
+			      IPMRA_VIFA_PAD) ||
+	    nla_put_u64_64bit(skb, IPMRA_VIFA_BYTES_OUT, vif->bytes_out,
+			      IPMRA_VIFA_PAD) ||
+	    nla_put_u64_64bit(skb, IPMRA_VIFA_PACKETS_IN, vif->pkt_in,
+			      IPMRA_VIFA_PAD) ||
+	    nla_put_u64_64bit(skb, IPMRA_VIFA_PACKETS_OUT, vif->pkt_out,
+			      IPMRA_VIFA_PAD) ||
+	    nla_put_be32(skb, IPMRA_VIFA_LOCAL_ADDR, vif->local) ||
+	    nla_put_be32(skb, IPMRA_VIFA_REMOTE_ADDR, vif->remote)) {
+		nla_nest_cancel(skb, vif_nest);
+		return false;
+	}
+	nla_nest_end(skb, vif_nest);
+
+	return true;
+}
+
+static int ipmr_valid_dumplink(const struct nlmsghdr *nlh,
+			       struct netlink_ext_ack *extack)
+{
+	struct ifinfomsg *ifm;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifm))) {
+		NL_SET_ERR_MSG(extack, "ipv4: Invalid header for ipmr link dump");
+		return -EINVAL;
+	}
+
+	if (nlmsg_attrlen(nlh, sizeof(*ifm))) {
+		NL_SET_ERR_MSG(extack, "Invalid data after header in ipmr link dump");
+		return -EINVAL;
+	}
+
+	ifm = nlmsg_data(nlh);
+	if (ifm->__ifi_pad || ifm->ifi_type || ifm->ifi_flags ||
+	    ifm->ifi_change || ifm->ifi_index) {
+		NL_SET_ERR_MSG(extack, "Invalid values in header for ipmr link dump request");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ipmr_rtm_dumplink(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct nlmsghdr *nlh = NULL;
+	unsigned int t = 0, s_t;
+	unsigned int e = 0, s_e;
+	struct mr_table *mrt;
+
+	if (cb->strict_check) {
+		int err = ipmr_valid_dumplink(cb->nlh, cb->extack);
+
+		if (err < 0)
+			return err;
+	}
+
+	s_t = cb->args[0];
+	s_e = cb->args[1];
+
+	ipmr_for_each_table(mrt, net) {
+		struct nlattr *vifs, *af;
+		struct ifinfomsg *hdr;
+		u32 i;
+
+		if (t < s_t)
+			goto skip_table;
+		nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+				cb->nlh->nlmsg_seq, RTM_NEWLINK,
+				sizeof(*hdr), NLM_F_MULTI);
+		if (!nlh)
+			break;
+
+		hdr = nlmsg_data(nlh);
+		memset(hdr, 0, sizeof(*hdr));
+		hdr->ifi_family = RTNL_FAMILY_IPMR;
+
+		af = nla_nest_start_noflag(skb, IFLA_AF_SPEC);
+		if (!af) {
+			nlmsg_cancel(skb, nlh);
+			goto out;
+		}
+
+		if (!ipmr_fill_table(mrt, skb)) {
+			nlmsg_cancel(skb, nlh);
+			goto out;
+		}
+
+		vifs = nla_nest_start_noflag(skb, IPMRA_TABLE_VIFS);
+		if (!vifs) {
+			nla_nest_end(skb, af);
+			nlmsg_end(skb, nlh);
+			goto out;
+		}
+		for (i = 0; i < mrt->maxvif; i++) {
+			if (e < s_e)
+				goto skip_entry;
+			if (!ipmr_fill_vif(mrt, i, skb)) {
+				nla_nest_end(skb, vifs);
+				nla_nest_end(skb, af);
+				nlmsg_end(skb, nlh);
+				goto out;
+			}
+skip_entry:
+			e++;
+		}
+		s_e = 0;
+		e = 0;
+		nla_nest_end(skb, vifs);
+		nla_nest_end(skb, af);
+		nlmsg_end(skb, nlh);
+skip_table:
+		t++;
+	}
+
+out:
+	cb->args[1] = e;
+	cb->args[0] = t;
+
+	return skb->len;
+}
+
+#ifdef CONFIG_PROC_FS
+/* The /proc interfaces to multicast routing :
+ * /proc/net/ip_mr_cache & /proc/net/ip_mr_vif
+ */
+
+static void *ipmr_vif_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	struct mr_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;
+
+	rcu_read_lock();
+	return mr_vif_seq_start(seq, pos);
+}
+
+static void ipmr_vif_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static int ipmr_vif_seq_show(struct seq_file *seq, void *v)
+{
+	struct mr_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 struct net_device *vif_dev;
+		const char *name;
+
+		vif_dev = vif_dev_read(vif);
+		name = vif_dev ? vif_dev->name : "none";
+		seq_printf(seq,
+			   "%2td %-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  = mr_vif_seq_next,
+	.stop  = ipmr_vif_seq_stop,
+	.show  = ipmr_vif_seq_show,
+};
+
+static void *ipmr_mfc_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	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);
+
+	return mr_mfc_seq_start(seq, pos, mrt, &mfc_unres_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 mfc_cache *mfc = v;
+		const struct mr_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->_c.mfc_parent);
+
+		if (it->cache != &mrt->mfc_unres_queue) {
+			seq_printf(seq, " %8lu %8lu %8lu",
+				   mfc->_c.mfc_un.res.pkt,
+				   mfc->_c.mfc_un.res.bytes,
+				   mfc->_c.mfc_un.res.wrong_if);
+			for (n = mfc->_c.mfc_un.res.minvif;
+			     n < mfc->_c.mfc_un.res.maxvif; n++) {
+				if (VIF_EXISTS(mrt, n) &&
+				    mfc->_c.mfc_un.res.ttls[n] < 255)
+					seq_printf(seq,
+					   " %2d:%-3d",
+					   n, mfc->_c.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  = mr_mfc_seq_next,
+	.stop  = mr_mfc_seq_stop,
+	.show  = ipmr_mfc_seq_show,
+};
+#endif
+
+#ifdef CONFIG_IP_PIMSM_V2
+static const struct net_protocol pim_protocol = {
+	.handler	=	pim_rcv,
+};
+#endif
+
+static unsigned int ipmr_seq_read(struct net *net)
+{
+	ASSERT_RTNL();
+
+	return net->ipv4.ipmr_seq + ipmr_rules_seq_read(net);
+}
+
+static int ipmr_dump(struct net *net, struct notifier_block *nb,
+		     struct netlink_ext_ack *extack)
+{
+	return mr_dump(net, nb, RTNL_FAMILY_IPMR, ipmr_rules_dump,
+		       ipmr_mr_table_iter, extack);
+}
+
+static const struct fib_notifier_ops ipmr_notifier_ops_template = {
+	.family		= RTNL_FAMILY_IPMR,
+	.fib_seq_read	= ipmr_seq_read,
+	.fib_dump	= ipmr_dump,
+	.owner		= THIS_MODULE,
+};
+
+static int __net_init ipmr_notifier_init(struct net *net)
+{
+	struct fib_notifier_ops *ops;
+
+	net->ipv4.ipmr_seq = 0;
+
+	ops = fib_notifier_ops_register(&ipmr_notifier_ops_template, net);
+	if (IS_ERR(ops))
+		return PTR_ERR(ops);
+	net->ipv4.ipmr_notifier_ops = ops;
+
+	return 0;
+}
+
+static void __net_exit ipmr_notifier_exit(struct net *net)
+{
+	fib_notifier_ops_unregister(net->ipv4.ipmr_notifier_ops);
+	net->ipv4.ipmr_notifier_ops = NULL;
+}
+
+/* Setup for IP multicast routing */
+static int __net_init ipmr_net_init(struct net *net)
+{
+	int err;
+
+	err = ipmr_notifier_init(net);
+	if (err)
+		goto ipmr_notifier_fail;
+
+	err = ipmr_rules_init(net);
+	if (err < 0)
+		goto ipmr_rules_fail;
+
+#ifdef CONFIG_PROC_FS
+	err = -ENOMEM;
+	if (!proc_create_net("ip_mr_vif", 0, net->proc_net, &ipmr_vif_seq_ops,
+			sizeof(struct mr_vif_iter)))
+		goto proc_vif_fail;
+	if (!proc_create_net("ip_mr_cache", 0, net->proc_net, &ipmr_mfc_seq_ops,
+			sizeof(struct mr_mfc_iter)))
+		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:
+	rtnl_lock();
+	ipmr_rules_exit(net);
+	rtnl_unlock();
+#endif
+ipmr_rules_fail:
+	ipmr_notifier_exit(net);
+ipmr_notifier_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_notifier_exit(net);
+}
+
+static void __net_exit ipmr_net_exit_batch(struct list_head *net_list)
+{
+	struct net *net;
+
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list)
+		ipmr_rules_exit(net);
+	rtnl_unlock();
+}
+
+static struct pernet_operations ipmr_net_ops = {
+	.init = ipmr_net_init,
+	.exit = ipmr_net_exit,
+	.exit_batch = ipmr_net_exit_batch,
+};
+
+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,
+		      ipmr_rtm_getroute, ipmr_rtm_dumproute, 0);
+	rtnl_register(RTNL_FAMILY_IPMR, RTM_NEWROUTE,
+		      ipmr_rtm_route, NULL, 0);
+	rtnl_register(RTNL_FAMILY_IPMR, RTM_DELROUTE,
+		      ipmr_rtm_route, NULL, 0);
+
+	rtnl_register(RTNL_FAMILY_IPMR, RTM_GETLINK,
+		      NULL, ipmr_rtm_dumplink, 0);
+	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;
+}