Initial import

1 files changed, 1946 insertions, 0 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
new file mode 100644
index 000000000..5cafd92c2
--- /dev/null
+++ b/net/ipv6/ip6_tunnel.c
@@ -0,0 +1,1946 @@
+/*
+ *	IPv6 tunneling device
+ *	Linux INET6 implementation
+ *
+ *	Authors:
+ *	Ville Nuorvala		<vnuorval@tcs.hut.fi>
+ *	Yasuyuki Kozakai	<kozakai@linux-ipv6.org>
+ *
+ *      Based on:
+ *      linux/net/ipv6/sit.c and linux/net/ipv4/ipip.c
+ *
+ *      RFC 2473
+ *
+ *	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.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/sockios.h>
+#include <linux/icmp.h>
+#include <linux/if.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/net.h>
+#include <linux/in6.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/icmpv6.h>
+#include <linux/init.h>
+#include <linux/route.h>
+#include <linux/rtnetlink.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/slab.h>
+#include <linux/hash.h>
+#include <linux/etherdevice.h>
+
+#include <asm/uaccess.h>
+#include <linux/atomic.h>
+
+#include <net/icmp.h>
+#include <net/ip.h>
+#include <net/ip_tunnels.h>
+#include <net/ipv6.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+#include <net/ip6_tunnel.h>
+#include <net/xfrm.h>
+#include <net/dsfield.h>
+#include <net/inet_ecn.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+MODULE_AUTHOR("Ville Nuorvala");
+MODULE_DESCRIPTION("IPv6 tunneling device");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("ip6tnl");
+MODULE_ALIAS_NETDEV("ip6tnl0");
+
+#define HASH_SIZE_SHIFT  5
+#define HASH_SIZE (1 << HASH_SIZE_SHIFT)
+
+static bool log_ecn_error = true;
+module_param(log_ecn_error, bool, 0644);
+MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
+
+static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
+{
+	u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
+
+	return hash_32(hash, HASH_SIZE_SHIFT);
+}
+
+static int ip6_tnl_dev_init(struct net_device *dev);
+static void ip6_tnl_dev_setup(struct net_device *dev);
+static struct rtnl_link_ops ip6_link_ops __read_mostly;
+
+static int ip6_tnl_net_id __read_mostly;
+struct ip6_tnl_net {
+	/* the IPv6 tunnel fallback device */
+	struct net_device *fb_tnl_dev;
+	/* lists for storing tunnels in use */
+	struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE];
+	struct ip6_tnl __rcu *tnls_wc[1];
+	struct ip6_tnl __rcu **tnls[2];
+};
+
+static struct net_device_stats *ip6_get_stats(struct net_device *dev)
+{
+	struct pcpu_sw_netstats tmp, sum = { 0 };
+	int i;
+
+	for_each_possible_cpu(i) {
+		unsigned int start;
+		const struct pcpu_sw_netstats *tstats =
+						   per_cpu_ptr(dev->tstats, i);
+
+		do {
+			start = u64_stats_fetch_begin_irq(&tstats->syncp);
+			tmp.rx_packets = tstats->rx_packets;
+			tmp.rx_bytes = tstats->rx_bytes;
+			tmp.tx_packets = tstats->tx_packets;
+			tmp.tx_bytes =  tstats->tx_bytes;
+		} while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
+
+		sum.rx_packets += tmp.rx_packets;
+		sum.rx_bytes   += tmp.rx_bytes;
+		sum.tx_packets += tmp.tx_packets;
+		sum.tx_bytes   += tmp.tx_bytes;
+	}
+	dev->stats.rx_packets = sum.rx_packets;
+	dev->stats.rx_bytes   = sum.rx_bytes;
+	dev->stats.tx_packets = sum.tx_packets;
+	dev->stats.tx_bytes   = sum.tx_bytes;
+	return &dev->stats;
+}
+
+/*
+ * Locking : hash tables are protected by RCU and RTNL
+ */
+
+struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
+{
+	struct dst_entry *dst = t->dst_cache;
+
+	if (dst && dst->obsolete &&
+	    !dst->ops->check(dst, t->dst_cookie)) {
+		t->dst_cache = NULL;
+		dst_release(dst);
+		return NULL;
+	}
+
+	return dst;
+}
+EXPORT_SYMBOL_GPL(ip6_tnl_dst_check);
+
+void ip6_tnl_dst_reset(struct ip6_tnl *t)
+{
+	dst_release(t->dst_cache);
+	t->dst_cache = NULL;
+}
+EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
+
+void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
+{
+	struct rt6_info *rt = (struct rt6_info *) dst;
+	t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+	dst_release(t->dst_cache);
+	t->dst_cache = dst;
+}
+EXPORT_SYMBOL_GPL(ip6_tnl_dst_store);
+
+/**
+ * ip6_tnl_lookup - fetch tunnel matching the end-point addresses
+ *   @remote: the address of the tunnel exit-point
+ *   @local: the address of the tunnel entry-point
+ *
+ * Return:
+ *   tunnel matching given end-points if found,
+ *   else fallback tunnel if its device is up,
+ *   else %NULL
+ **/
+
+#define for_each_ip6_tunnel_rcu(start) \
+	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
+
+static struct ip6_tnl *
+ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)
+{
+	unsigned int hash = HASH(remote, local);
+	struct ip6_tnl *t;
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	struct in6_addr any;
+
+	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
+		if (ipv6_addr_equal(local, &t->parms.laddr) &&
+		    ipv6_addr_equal(remote, &t->parms.raddr) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+
+	memset(&any, 0, sizeof(any));
+	hash = HASH(&any, local);
+	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
+		if (ipv6_addr_equal(local, &t->parms.laddr) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+
+	hash = HASH(remote, &any);
+	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
+		if (ipv6_addr_equal(remote, &t->parms.raddr) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+
+	t = rcu_dereference(ip6n->tnls_wc[0]);
+	if (t && (t->dev->flags & IFF_UP))
+		return t;
+
+	return NULL;
+}
+
+/**
+ * ip6_tnl_bucket - get head of list matching given tunnel parameters
+ *   @p: parameters containing tunnel end-points
+ *
+ * Description:
+ *   ip6_tnl_bucket() returns the head of the list matching the
+ *   &struct in6_addr entries laddr and raddr in @p.
+ *
+ * Return: head of IPv6 tunnel list
+ **/
+
+static struct ip6_tnl __rcu **
+ip6_tnl_bucket(struct ip6_tnl_net *ip6n, const struct __ip6_tnl_parm *p)
+{
+	const struct in6_addr *remote = &p->raddr;
+	const struct in6_addr *local = &p->laddr;
+	unsigned int h = 0;
+	int prio = 0;
+
+	if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
+		prio = 1;
+		h = HASH(remote, local);
+	}
+	return &ip6n->tnls[prio][h];
+}
+
+/**
+ * ip6_tnl_link - add tunnel to hash table
+ *   @t: tunnel to be added
+ **/
+
+static void
+ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
+{
+	struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms);
+
+	rcu_assign_pointer(t->next , rtnl_dereference(*tp));
+	rcu_assign_pointer(*tp, t);
+}
+
+/**
+ * ip6_tnl_unlink - remove tunnel from hash table
+ *   @t: tunnel to be removed
+ **/
+
+static void
+ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
+{
+	struct ip6_tnl __rcu **tp;
+	struct ip6_tnl *iter;
+
+	for (tp = ip6_tnl_bucket(ip6n, &t->parms);
+	     (iter = rtnl_dereference(*tp)) != NULL;
+	     tp = &iter->next) {
+		if (t == iter) {
+			rcu_assign_pointer(*tp, t->next);
+			break;
+		}
+	}
+}
+
+static void ip6_dev_free(struct net_device *dev)
+{
+	free_percpu(dev->tstats);
+	free_netdev(dev);
+}
+
+static int ip6_tnl_create2(struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct net *net = dev_net(dev);
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	int err;
+
+	t = netdev_priv(dev);
+
+	err = register_netdevice(dev);
+	if (err < 0)
+		goto out;
+
+	strcpy(t->parms.name, dev->name);
+	dev->rtnl_link_ops = &ip6_link_ops;
+
+	dev_hold(dev);
+	ip6_tnl_link(ip6n, t);
+	return 0;
+
+out:
+	return err;
+}
+
+/**
+ * ip6_tnl_create - create a new tunnel
+ *   @p: tunnel parameters
+ *   @pt: pointer to new tunnel
+ *
+ * Description:
+ *   Create tunnel matching given parameters.
+ *
+ * Return:
+ *   created tunnel or error pointer
+ **/
+
+static struct ip6_tnl *ip6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
+{
+	struct net_device *dev;
+	struct ip6_tnl *t;
+	char name[IFNAMSIZ];
+	int err = -ENOMEM;
+
+	if (p->name[0])
+		strlcpy(name, p->name, IFNAMSIZ);
+	else
+		sprintf(name, "ip6tnl%%d");
+
+	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
+			   ip6_tnl_dev_setup);
+	if (!dev)
+		goto failed;
+
+	dev_net_set(dev, net);
+
+	t = netdev_priv(dev);
+	t->parms = *p;
+	t->net = dev_net(dev);
+	err = ip6_tnl_create2(dev);
+	if (err < 0)
+		goto failed_free;
+
+	return t;
+
+failed_free:
+	ip6_dev_free(dev);
+failed:
+	return ERR_PTR(err);
+}
+
+/**
+ * ip6_tnl_locate - find or create tunnel matching given parameters
+ *   @p: tunnel parameters
+ *   @create: != 0 if allowed to create new tunnel if no match found
+ *
+ * Description:
+ *   ip6_tnl_locate() first tries to locate an existing tunnel
+ *   based on @parms. If this is unsuccessful, but @create is set a new
+ *   tunnel device is created and registered for use.
+ *
+ * Return:
+ *   matching tunnel or error pointer
+ **/
+
+static struct ip6_tnl *ip6_tnl_locate(struct net *net,
+		struct __ip6_tnl_parm *p, int create)
+{
+	const struct in6_addr *remote = &p->raddr;
+	const struct in6_addr *local = &p->laddr;
+	struct ip6_tnl __rcu **tp;
+	struct ip6_tnl *t;
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+
+	for (tp = ip6_tnl_bucket(ip6n, p);
+	     (t = rtnl_dereference(*tp)) != NULL;
+	     tp = &t->next) {
+		if (ipv6_addr_equal(local, &t->parms.laddr) &&
+		    ipv6_addr_equal(remote, &t->parms.raddr)) {
+			if (create)
+				return ERR_PTR(-EEXIST);
+
+			return t;
+		}
+	}
+	if (!create)
+		return ERR_PTR(-ENODEV);
+	return ip6_tnl_create(net, p);
+}
+
+/**
+ * ip6_tnl_dev_uninit - tunnel device uninitializer
+ *   @dev: the device to be destroyed
+ *
+ * Description:
+ *   ip6_tnl_dev_uninit() removes tunnel from its list
+ **/
+
+static void
+ip6_tnl_dev_uninit(struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct net *net = t->net;
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+
+	if (dev == ip6n->fb_tnl_dev)
+		RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
+	else
+		ip6_tnl_unlink(ip6n, t);
+	ip6_tnl_dst_reset(t);
+	dev_put(dev);
+}
+
+/**
+ * parse_tvl_tnl_enc_lim - handle encapsulation limit option
+ *   @skb: received socket buffer
+ *
+ * Return:
+ *   0 if none was found,
+ *   else index to encapsulation limit
+ **/
+
+__u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
+{
+	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) raw;
+	__u8 nexthdr = ipv6h->nexthdr;
+	__u16 off = sizeof(*ipv6h);
+
+	while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
+		__u16 optlen = 0;
+		struct ipv6_opt_hdr *hdr;
+		if (raw + off + sizeof(*hdr) > skb->data &&
+		    !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
+			break;
+
+		hdr = (struct ipv6_opt_hdr *) (raw + off);
+		if (nexthdr == NEXTHDR_FRAGMENT) {
+			struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
+			if (frag_hdr->frag_off)
+				break;
+			optlen = 8;
+		} else if (nexthdr == NEXTHDR_AUTH) {
+			optlen = (hdr->hdrlen + 2) << 2;
+		} else {
+			optlen = ipv6_optlen(hdr);
+		}
+		if (nexthdr == NEXTHDR_DEST) {
+			__u16 i = off + 2;
+			while (1) {
+				struct ipv6_tlv_tnl_enc_lim *tel;
+
+				/* No more room for encapsulation limit */
+				if (i + sizeof (*tel) > off + optlen)
+					break;
+
+				tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
+				/* return index of option if found and valid */
+				if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
+				    tel->length == 1)
+					return i;
+				/* else jump to next option */
+				if (tel->type)
+					i += tel->length + 2;
+				else
+					i++;
+			}
+		}
+		nexthdr = hdr->nexthdr;
+		off += optlen;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(ip6_tnl_parse_tlv_enc_lim);
+
+/**
+ * ip6_tnl_err - tunnel error handler
+ *
+ * Description:
+ *   ip6_tnl_err() should handle errors in the tunnel according
+ *   to the specifications in RFC 2473.
+ **/
+
+static int
+ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
+	    u8 *type, u8 *code, int *msg, __u32 *info, int offset)
+{
+	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) skb->data;
+	struct ip6_tnl *t;
+	int rel_msg = 0;
+	u8 rel_type = ICMPV6_DEST_UNREACH;
+	u8 rel_code = ICMPV6_ADDR_UNREACH;
+	u8 tproto;
+	__u32 rel_info = 0;
+	__u16 len;
+	int err = -ENOENT;
+
+	/* If the packet doesn't contain the original IPv6 header we are
+	   in trouble since we might need the source address for further
+	   processing of the error. */
+
+	rcu_read_lock();
+	t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr, &ipv6h->saddr);
+	if (!t)
+		goto out;
+
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if (tproto != ipproto && tproto != 0)
+		goto out;
+
+	err = 0;
+
+	switch (*type) {
+		__u32 teli;
+		struct ipv6_tlv_tnl_enc_lim *tel;
+		__u32 mtu;
+	case ICMPV6_DEST_UNREACH:
+		net_warn_ratelimited("%s: Path to destination invalid or inactive!\n",
+				     t->parms.name);
+		rel_msg = 1;
+		break;
+	case ICMPV6_TIME_EXCEED:
+		if ((*code) == ICMPV6_EXC_HOPLIMIT) {
+			net_warn_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
+					     t->parms.name);
+			rel_msg = 1;
+		}
+		break;
+	case ICMPV6_PARAMPROB:
+		teli = 0;
+		if ((*code) == ICMPV6_HDR_FIELD)
+			teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
+
+		if (teli && teli == *info - 2) {
+			tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
+			if (tel->encap_limit == 0) {
+				net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
+						     t->parms.name);
+				rel_msg = 1;
+			}
+		} else {
+			net_warn_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
+					     t->parms.name);
+		}
+		break;
+	case ICMPV6_PKT_TOOBIG:
+		mtu = *info - offset;
+		if (mtu < IPV6_MIN_MTU)
+			mtu = IPV6_MIN_MTU;
+		t->dev->mtu = mtu;
+
+		len = sizeof(*ipv6h) + ntohs(ipv6h->payload_len);
+		if (len > mtu) {
+			rel_type = ICMPV6_PKT_TOOBIG;
+			rel_code = 0;
+			rel_info = mtu;
+			rel_msg = 1;
+		}
+		break;
+	}
+
+	*type = rel_type;
+	*code = rel_code;
+	*info = rel_info;
+	*msg = rel_msg;
+
+out:
+	rcu_read_unlock();
+	return err;
+}
+
+static int
+ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+	   u8 type, u8 code, int offset, __be32 info)
+{
+	int rel_msg = 0;
+	u8 rel_type = type;
+	u8 rel_code = code;
+	__u32 rel_info = ntohl(info);
+	int err;
+	struct sk_buff *skb2;
+	const struct iphdr *eiph;
+	struct rtable *rt;
+	struct flowi4 fl4;
+
+	err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
+			  &rel_msg, &rel_info, offset);
+	if (err < 0)
+		return err;
+
+	if (rel_msg == 0)
+		return 0;
+
+	switch (rel_type) {
+	case ICMPV6_DEST_UNREACH:
+		if (rel_code != ICMPV6_ADDR_UNREACH)
+			return 0;
+		rel_type = ICMP_DEST_UNREACH;
+		rel_code = ICMP_HOST_UNREACH;
+		break;
+	case ICMPV6_PKT_TOOBIG:
+		if (rel_code != 0)
+			return 0;
+		rel_type = ICMP_DEST_UNREACH;
+		rel_code = ICMP_FRAG_NEEDED;
+		break;
+	case NDISC_REDIRECT:
+		rel_type = ICMP_REDIRECT;
+		rel_code = ICMP_REDIR_HOST;
+	default:
+		return 0;
+	}
+
+	if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
+		return 0;
+
+	skb2 = skb_clone(skb, GFP_ATOMIC);
+	if (!skb2)
+		return 0;
+
+	skb_dst_drop(skb2);
+
+	skb_pull(skb2, offset);
+	skb_reset_network_header(skb2);
+	eiph = ip_hdr(skb2);
+
+	/* Try to guess incoming interface */
+	rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
+				   eiph->saddr, 0,
+				   0, 0,
+				   IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
+	if (IS_ERR(rt))
+		goto out;
+
+	skb2->dev = rt->dst.dev;
+
+	/* route "incoming" packet */
+	if (rt->rt_flags & RTCF_LOCAL) {
+		ip_rt_put(rt);
+		rt = NULL;
+		rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
+					   eiph->daddr, eiph->saddr,
+					   0, 0,
+					   IPPROTO_IPIP,
+					   RT_TOS(eiph->tos), 0);
+		if (IS_ERR(rt) ||
+		    rt->dst.dev->type != ARPHRD_TUNNEL) {
+			if (!IS_ERR(rt))
+				ip_rt_put(rt);
+			goto out;
+		}
+		skb_dst_set(skb2, &rt->dst);
+	} else {
+		ip_rt_put(rt);
+		if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
+				   skb2->dev) ||
+		    skb_dst(skb2)->dev->type != ARPHRD_TUNNEL)
+			goto out;
+	}
+
+	/* change mtu on this route */
+	if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {
+		if (rel_info > dst_mtu(skb_dst(skb2)))
+			goto out;
+
+		skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
+	}
+	if (rel_type == ICMP_REDIRECT)
+		skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
+
+	icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
+
+out:
+	kfree_skb(skb2);
+	return 0;
+}
+
+static int
+ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+	   u8 type, u8 code, int offset, __be32 info)
+{
+	int rel_msg = 0;
+	u8 rel_type = type;
+	u8 rel_code = code;
+	__u32 rel_info = ntohl(info);
+	int err;
+
+	err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
+			  &rel_msg, &rel_info, offset);
+	if (err < 0)
+		return err;
+
+	if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) {
+		struct rt6_info *rt;
+		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
+
+		if (!skb2)
+			return 0;
+
+		skb_dst_drop(skb2);
+		skb_pull(skb2, offset);
+		skb_reset_network_header(skb2);
+
+		/* Try to guess incoming interface */
+		rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr,
+				NULL, 0, 0);
+
+		if (rt && rt->dst.dev)
+			skb2->dev = rt->dst.dev;
+
+		icmpv6_send(skb2, rel_type, rel_code, rel_info);
+
+		ip6_rt_put(rt);
+
+		kfree_skb(skb2);
+	}
+
+	return 0;
+}
+
+static int ip4ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
+				       const struct ipv6hdr *ipv6h,
+				       struct sk_buff *skb)
+{
+	__u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;
+
+	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
+		ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield);
+
+	return IP6_ECN_decapsulate(ipv6h, skb);
+}
+
+static int ip6ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
+				       const struct ipv6hdr *ipv6h,
+				       struct sk_buff *skb)
+{
+	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
+		ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb));
+
+	return IP6_ECN_decapsulate(ipv6h, skb);
+}
+
+__u32 ip6_tnl_get_cap(struct ip6_tnl *t,
+			     const struct in6_addr *laddr,
+			     const struct in6_addr *raddr)
+{
+	struct __ip6_tnl_parm *p = &t->parms;
+	int ltype = ipv6_addr_type(laddr);
+	int rtype = ipv6_addr_type(raddr);
+	__u32 flags = 0;
+
+	if (ltype == IPV6_ADDR_ANY || rtype == IPV6_ADDR_ANY) {
+		flags = IP6_TNL_F_CAP_PER_PACKET;
+	} else if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
+		   rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
+		   !((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
+		   (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
+		if (ltype&IPV6_ADDR_UNICAST)
+			flags |= IP6_TNL_F_CAP_XMIT;
+		if (rtype&IPV6_ADDR_UNICAST)
+			flags |= IP6_TNL_F_CAP_RCV;
+	}
+	return flags;
+}
+EXPORT_SYMBOL(ip6_tnl_get_cap);
+
+/* called with rcu_read_lock() */
+int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
+				  const struct in6_addr *laddr,
+				  const struct in6_addr *raddr)
+{
+	struct __ip6_tnl_parm *p = &t->parms;
+	int ret = 0;
+	struct net *net = t->net;
+
+	if ((p->flags & IP6_TNL_F_CAP_RCV) ||
+	    ((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
+	     (ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_RCV))) {
+		struct net_device *ldev = NULL;
+
+		if (p->link)
+			ldev = dev_get_by_index_rcu(net, p->link);
+
+		if ((ipv6_addr_is_multicast(laddr) ||
+		     likely(ipv6_chk_addr(net, laddr, ldev, 0))) &&
+		    likely(!ipv6_chk_addr(net, raddr, NULL, 0)))
+			ret = 1;
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
+
+/**
+ * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
+ *   @skb: received socket buffer
+ *   @protocol: ethernet protocol ID
+ *   @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
+ *
+ * Return: 0
+ **/
+
+static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
+		       __u8 ipproto,
+		       int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
+						   const struct ipv6hdr *ipv6h,
+						   struct sk_buff *skb))
+{
+	struct ip6_tnl *t;
+	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	u8 tproto;
+	int err;
+
+	rcu_read_lock();
+	t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
+	if (t) {
+		struct pcpu_sw_netstats *tstats;
+
+		tproto = ACCESS_ONCE(t->parms.proto);
+		if (tproto != ipproto && tproto != 0) {
+			rcu_read_unlock();
+			goto discard;
+		}
+
+		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+			rcu_read_unlock();
+			goto discard;
+		}
+
+		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
+			t->dev->stats.rx_dropped++;
+			rcu_read_unlock();
+			goto discard;
+		}
+		skb->mac_header = skb->network_header;
+		skb_reset_network_header(skb);
+		skb->protocol = htons(protocol);
+		memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
+
+		__skb_tunnel_rx(skb, t->dev, t->net);
+
+		err = dscp_ecn_decapsulate(t, ipv6h, skb);
+		if (unlikely(err)) {
+			if (log_ecn_error)
+				net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
+						     &ipv6h->saddr,
+						     ipv6_get_dsfield(ipv6h));
+			if (err > 1) {
+				++t->dev->stats.rx_frame_errors;
+				++t->dev->stats.rx_errors;
+				rcu_read_unlock();
+				goto discard;
+			}
+		}
+
+		tstats = this_cpu_ptr(t->dev->tstats);
+		u64_stats_update_begin(&tstats->syncp);
+		tstats->rx_packets++;
+		tstats->rx_bytes += skb->len;
+		u64_stats_update_end(&tstats->syncp);
+
+		netif_rx(skb);
+
+		rcu_read_unlock();
+		return 0;
+	}
+	rcu_read_unlock();
+	return 1;
+
+discard:
+	kfree_skb(skb);
+	return 0;
+}
+
+static int ip4ip6_rcv(struct sk_buff *skb)
+{
+	return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
+			   ip4ip6_dscp_ecn_decapsulate);
+}
+
+static int ip6ip6_rcv(struct sk_buff *skb)
+{
+	return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
+			   ip6ip6_dscp_ecn_decapsulate);
+}
+
+struct ipv6_tel_txoption {
+	struct ipv6_txoptions ops;
+	__u8 dst_opt[8];
+};
+
+static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
+{
+	memset(opt, 0, sizeof(struct ipv6_tel_txoption));
+
+	opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
+	opt->dst_opt[3] = 1;
+	opt->dst_opt[4] = encap_limit;
+	opt->dst_opt[5] = IPV6_TLV_PADN;
+	opt->dst_opt[6] = 1;
+
+	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
+	opt->ops.opt_nflen = 8;
+}
+
+/**
+ * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
+ *   @t: the outgoing tunnel device
+ *   @hdr: IPv6 header from the incoming packet
+ *
+ * Description:
+ *   Avoid trivial tunneling loop by checking that tunnel exit-point
+ *   doesn't match source of incoming packet.
+ *
+ * Return:
+ *   1 if conflict,
+ *   0 else
+ **/
+
+static inline bool
+ip6_tnl_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
+{
+	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
+}
+
+int ip6_tnl_xmit_ctl(struct ip6_tnl *t,
+		     const struct in6_addr *laddr,
+		     const struct in6_addr *raddr)
+{
+	struct __ip6_tnl_parm *p = &t->parms;
+	int ret = 0;
+	struct net *net = t->net;
+
+	if ((p->flags & IP6_TNL_F_CAP_XMIT) ||
+	    ((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
+	     (ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_XMIT))) {
+		struct net_device *ldev = NULL;
+
+		rcu_read_lock();
+		if (p->link)
+			ldev = dev_get_by_index_rcu(net, p->link);
+
+		if (unlikely(!ipv6_chk_addr(net, laddr, ldev, 0)))
+			pr_warn("%s xmit: Local address not yet configured!\n",
+				p->name);
+		else if (!ipv6_addr_is_multicast(raddr) &&
+			 unlikely(ipv6_chk_addr(net, raddr, NULL, 0)))
+			pr_warn("%s xmit: Routing loop! Remote address found on this node!\n",
+				p->name);
+		else
+			ret = 1;
+		rcu_read_unlock();
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
+
+/**
+ * ip6_tnl_xmit2 - encapsulate packet and send
+ *   @skb: the outgoing socket buffer
+ *   @dev: the outgoing tunnel device
+ *   @dsfield: dscp code for outer header
+ *   @fl: flow of tunneled packet
+ *   @encap_limit: encapsulation limit
+ *   @pmtu: Path MTU is stored if packet is too big
+ *
+ * Description:
+ *   Build new header and do some sanity checks on the packet before sending
+ *   it.
+ *
+ * Return:
+ *   0 on success
+ *   -1 fail
+ *   %-EMSGSIZE message too big. return mtu in this case.
+ **/
+
+static int ip6_tnl_xmit2(struct sk_buff *skb,
+			 struct net_device *dev,
+			 __u8 dsfield,
+			 struct flowi6 *fl6,
+			 int encap_limit,
+			 __u32 *pmtu)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct net *net = t->net;
+	struct net_device_stats *stats = &t->dev->stats;
+	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	struct ipv6_tel_txoption opt;
+	struct dst_entry *dst = NULL, *ndst = NULL;
+	struct net_device *tdev;
+	int mtu;
+	unsigned int max_headroom = sizeof(struct ipv6hdr);
+	u8 proto;
+	int err = -1;
+
+	/* NBMA tunnel */
+	if (ipv6_addr_any(&t->parms.raddr)) {
+		struct in6_addr *addr6;
+		struct neighbour *neigh;
+		int addr_type;
+
+		if (!skb_dst(skb))
+			goto tx_err_link_failure;
+
+		neigh = dst_neigh_lookup(skb_dst(skb),
+					 &ipv6_hdr(skb)->daddr);
+		if (!neigh)
+			goto tx_err_link_failure;
+
+		addr6 = (struct in6_addr *)&neigh->primary_key;
+		addr_type = ipv6_addr_type(addr6);
+
+		if (addr_type == IPV6_ADDR_ANY)
+			addr6 = &ipv6_hdr(skb)->daddr;
+
+		memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
+		neigh_release(neigh);
+	} else if (!fl6->flowi6_mark)
+		dst = ip6_tnl_dst_check(t);
+
+	if (!ip6_tnl_xmit_ctl(t, &fl6->saddr, &fl6->daddr))
+		goto tx_err_link_failure;
+
+	if (!dst) {
+		ndst = ip6_route_output(net, NULL, fl6);
+
+		if (ndst->error)
+			goto tx_err_link_failure;
+		ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0);
+		if (IS_ERR(ndst)) {
+			err = PTR_ERR(ndst);
+			ndst = NULL;
+			goto tx_err_link_failure;
+		}
+		dst = ndst;
+	}
+
+	tdev = dst->dev;
+
+	if (tdev == dev) {
+		stats->collisions++;
+		net_warn_ratelimited("%s: Local routing loop detected!\n",
+				     t->parms.name);
+		goto tx_err_dst_release;
+	}
+	mtu = dst_mtu(dst) - sizeof(*ipv6h);
+	if (encap_limit >= 0) {
+		max_headroom += 8;
+		mtu -= 8;
+	}
+	if (mtu < IPV6_MIN_MTU)
+		mtu = IPV6_MIN_MTU;
+	if (skb_dst(skb))
+		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+	if (skb->len > mtu) {
+		*pmtu = mtu;
+		err = -EMSGSIZE;
+		goto tx_err_dst_release;
+	}
+
+	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
+
+	/*
+	 * Okay, now see if we can stuff it in the buffer as-is.
+	 */
+	max_headroom += LL_RESERVED_SPACE(tdev);
+
+	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
+	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
+		struct sk_buff *new_skb;
+
+		new_skb = skb_realloc_headroom(skb, max_headroom);
+		if (!new_skb)
+			goto tx_err_dst_release;
+
+		if (skb->sk)
+			skb_set_owner_w(new_skb, skb->sk);
+		consume_skb(skb);
+		skb = new_skb;
+	}
+	if (fl6->flowi6_mark) {
+		skb_dst_set(skb, dst);
+		ndst = NULL;
+	} else {
+		skb_dst_set_noref(skb, dst);
+	}
+	skb->transport_header = skb->network_header;
+
+	proto = fl6->flowi6_proto;
+	if (encap_limit >= 0) {
+		init_tel_txopt(&opt, encap_limit);
+		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
+	}
+
+	if (likely(!skb->encapsulation)) {
+		skb_reset_inner_headers(skb);
+		skb->encapsulation = 1;
+	}
+
+	skb_push(skb, sizeof(struct ipv6hdr));
+	skb_reset_network_header(skb);
+	ipv6h = ipv6_hdr(skb);
+	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
+		     ip6_make_flowlabel(net, skb, fl6->flowlabel, false));
+	ipv6h->hop_limit = t->parms.hop_limit;
+	ipv6h->nexthdr = proto;
+	ipv6h->saddr = fl6->saddr;
+	ipv6h->daddr = fl6->daddr;
+	ip6tunnel_xmit(NULL, skb, dev);
+	if (ndst)
+		ip6_tnl_dst_store(t, ndst);
+	return 0;
+tx_err_link_failure:
+	stats->tx_carrier_errors++;
+	dst_link_failure(skb);
+tx_err_dst_release:
+	dst_release(ndst);
+	return err;
+}
+
+static inline int
+ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	const struct iphdr  *iph = ip_hdr(skb);
+	int encap_limit = -1;
+	struct flowi6 fl6;
+	__u8 dsfield;
+	__u32 mtu;
+	u8 tproto;
+	int err;
+
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if (tproto != IPPROTO_IPIP && tproto != 0)
+		return -1;
+
+	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+		encap_limit = t->parms.encap_limit;
+
+	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
+	fl6.flowi6_proto = IPPROTO_IPIP;
+
+	dsfield = ipv4_get_dsfield(iph);
+
+	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
+		fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
+					  & IPV6_TCLASS_MASK;
+	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
+		fl6.flowi6_mark = skb->mark;
+
+	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+	if (err != 0) {
+		/* XXX: send ICMP error even if DF is not set. */
+		if (err == -EMSGSIZE)
+			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+				  htonl(mtu));
+		return -1;
+	}
+
+	return 0;
+}
+
+static inline int
+ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+	int encap_limit = -1;
+	__u16 offset;
+	struct flowi6 fl6;
+	__u8 dsfield;
+	__u32 mtu;
+	u8 tproto;
+	int err;
+
+	tproto = ACCESS_ONCE(t->parms.proto);
+	if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
+	    ip6_tnl_addr_conflict(t, ipv6h))
+		return -1;
+
+	offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
+	if (offset > 0) {
+		struct ipv6_tlv_tnl_enc_lim *tel;
+		tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
+		if (tel->encap_limit == 0) {
+			icmpv6_send(skb, ICMPV6_PARAMPROB,
+				    ICMPV6_HDR_FIELD, offset + 2);
+			return -1;
+		}
+		encap_limit = tel->encap_limit - 1;
+	} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+		encap_limit = t->parms.encap_limit;
+
+	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
+	fl6.flowi6_proto = IPPROTO_IPV6;
+
+	dsfield = ipv6_get_dsfield(ipv6h);
+	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
+		fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
+	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
+		fl6.flowlabel |= ip6_flowlabel(ipv6h);
+	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
+		fl6.flowi6_mark = skb->mark;
+
+	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+	if (err != 0) {
+		if (err == -EMSGSIZE)
+			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+		return -1;
+	}
+
+	return 0;
+}
+
+static netdev_tx_t
+ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct net_device_stats *stats = &t->dev->stats;
+	int ret;
+
+	switch (skb->protocol) {
+	case htons(ETH_P_IP):
+		ret = ip4ip6_tnl_xmit(skb, dev);
+		break;
+	case htons(ETH_P_IPV6):
+		ret = ip6ip6_tnl_xmit(skb, dev);
+		break;
+	default:
+		goto tx_err;
+	}
+
+	if (ret < 0)
+		goto tx_err;
+
+	return NETDEV_TX_OK;
+
+tx_err:
+	stats->tx_errors++;
+	stats->tx_dropped++;
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+static void ip6_tnl_link_config(struct ip6_tnl *t)
+{
+	struct net_device *dev = t->dev;
+	struct __ip6_tnl_parm *p = &t->parms;
+	struct flowi6 *fl6 = &t->fl.u.ip6;
+
+	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
+	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
+
+	/* Set up flowi template */
+	fl6->saddr = p->laddr;
+	fl6->daddr = p->raddr;
+	fl6->flowi6_oif = p->link;
+	fl6->flowlabel = 0;
+
+	if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
+		fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
+	if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
+		fl6->flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
+
+	p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV|IP6_TNL_F_CAP_PER_PACKET);
+	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
+
+	if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
+		dev->flags |= IFF_POINTOPOINT;
+	else
+		dev->flags &= ~IFF_POINTOPOINT;
+
+	if (p->flags & IP6_TNL_F_CAP_XMIT) {
+		int strict = (ipv6_addr_type(&p->raddr) &
+			      (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
+
+		struct rt6_info *rt = rt6_lookup(t->net,
+						 &p->raddr, &p->laddr,
+						 p->link, strict);
+
+		if (!rt)
+			return;
+
+		if (rt->dst.dev) {
+			dev->hard_header_len = rt->dst.dev->hard_header_len +
+				sizeof(struct ipv6hdr);
+
+			dev->mtu = rt->dst.dev->mtu - sizeof(struct ipv6hdr);
+			if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+				dev->mtu -= 8;
+
+			if (dev->mtu < IPV6_MIN_MTU)
+				dev->mtu = IPV6_MIN_MTU;
+		}
+		ip6_rt_put(rt);
+	}
+}
+
+/**
+ * ip6_tnl_change - update the tunnel parameters
+ *   @t: tunnel to be changed
+ *   @p: tunnel configuration parameters
+ *
+ * Description:
+ *   ip6_tnl_change() updates the tunnel parameters
+ **/
+
+static int
+ip6_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p)
+{
+	t->parms.laddr = p->laddr;
+	t->parms.raddr = p->raddr;
+	t->parms.flags = p->flags;
+	t->parms.hop_limit = p->hop_limit;
+	t->parms.encap_limit = p->encap_limit;
+	t->parms.flowinfo = p->flowinfo;
+	t->parms.link = p->link;
+	t->parms.proto = p->proto;
+	ip6_tnl_dst_reset(t);
+	ip6_tnl_link_config(t);
+	return 0;
+}
+
+static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
+{
+	struct net *net = t->net;
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	int err;
+
+	ip6_tnl_unlink(ip6n, t);
+	synchronize_net();
+	err = ip6_tnl_change(t, p);
+	ip6_tnl_link(ip6n, t);
+	netdev_state_change(t->dev);
+	return err;
+}
+
+static int ip6_tnl0_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
+{
+	/* for default tnl0 device allow to change only the proto */
+	t->parms.proto = p->proto;
+	netdev_state_change(t->dev);
+	return 0;
+}
+
+static void
+ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
+{
+	p->laddr = u->laddr;
+	p->raddr = u->raddr;
+	p->flags = u->flags;
+	p->hop_limit = u->hop_limit;
+	p->encap_limit = u->encap_limit;
+	p->flowinfo = u->flowinfo;
+	p->link = u->link;
+	p->proto = u->proto;
+	memcpy(p->name, u->name, sizeof(u->name));
+}
+
+static void
+ip6_tnl_parm_to_user(struct ip6_tnl_parm *u, const struct __ip6_tnl_parm *p)
+{
+	u->laddr = p->laddr;
+	u->raddr = p->raddr;
+	u->flags = p->flags;
+	u->hop_limit = p->hop_limit;
+	u->encap_limit = p->encap_limit;
+	u->flowinfo = p->flowinfo;
+	u->link = p->link;
+	u->proto = p->proto;
+	memcpy(u->name, p->name, sizeof(u->name));
+}
+
+/**
+ * ip6_tnl_ioctl - configure ipv6 tunnels from userspace
+ *   @dev: virtual device associated with tunnel
+ *   @ifr: parameters passed from userspace
+ *   @cmd: command to be performed
+ *
+ * Description:
+ *   ip6_tnl_ioctl() is used for managing IPv6 tunnels
+ *   from userspace.
+ *
+ *   The possible commands are the following:
+ *     %SIOCGETTUNNEL: get tunnel parameters for device
+ *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
+ *     %SIOCCHGTUNNEL: change tunnel parameters to those given
+ *     %SIOCDELTUNNEL: delete tunnel
+ *
+ *   The fallback device "ip6tnl0", created during module
+ *   initialization, can be used for creating other tunnel devices.
+ *
+ * Return:
+ *   0 on success,
+ *   %-EFAULT if unable to copy data to or from userspace,
+ *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
+ *   %-EINVAL if passed tunnel parameters are invalid,
+ *   %-EEXIST if changing a tunnel's parameters would cause a conflict
+ *   %-ENODEV if attempting to change or delete a nonexisting device
+ **/
+
+static int
+ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	int err = 0;
+	struct ip6_tnl_parm p;
+	struct __ip6_tnl_parm p1;
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct net *net = t->net;
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+
+	switch (cmd) {
+	case SIOCGETTUNNEL:
+		if (dev == ip6n->fb_tnl_dev) {
+			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
+				err = -EFAULT;
+				break;
+			}
+			ip6_tnl_parm_from_user(&p1, &p);
+			t = ip6_tnl_locate(net, &p1, 0);
+			if (IS_ERR(t))
+				t = netdev_priv(dev);
+		} else {
+			memset(&p, 0, sizeof(p));
+		}
+		ip6_tnl_parm_to_user(&p, &t->parms);
+		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) {
+			err = -EFAULT;
+		}
+		break;
+	case SIOCADDTUNNEL:
+	case SIOCCHGTUNNEL:
+		err = -EPERM;
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+			break;
+		err = -EFAULT;
+		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+			break;
+		err = -EINVAL;
+		if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP &&
+		    p.proto != 0)
+			break;
+		ip6_tnl_parm_from_user(&p1, &p);
+		t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
+		if (cmd == SIOCCHGTUNNEL) {
+			if (!IS_ERR(t)) {
+				if (t->dev != dev) {
+					err = -EEXIST;
+					break;
+				}
+			} else
+				t = netdev_priv(dev);
+			if (dev == ip6n->fb_tnl_dev)
+				err = ip6_tnl0_update(t, &p1);
+			else
+				err = ip6_tnl_update(t, &p1);
+		}
+		if (!IS_ERR(t)) {
+			err = 0;
+			ip6_tnl_parm_to_user(&p, &t->parms);
+			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
+				err = -EFAULT;
+
+		} else {
+			err = PTR_ERR(t);
+		}
+		break;
+	case SIOCDELTUNNEL:
+		err = -EPERM;
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+			break;
+
+		if (dev == ip6n->fb_tnl_dev) {
+			err = -EFAULT;
+			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+				break;
+			err = -ENOENT;
+			ip6_tnl_parm_from_user(&p1, &p);
+			t = ip6_tnl_locate(net, &p1, 0);
+			if (IS_ERR(t))
+				break;
+			err = -EPERM;
+			if (t->dev == ip6n->fb_tnl_dev)
+				break;
+			dev = t->dev;
+		}
+		err = 0;
+		unregister_netdevice(dev);
+		break;
+	default:
+		err = -EINVAL;
+	}
+	return err;
+}
+
+/**
+ * ip6_tnl_change_mtu - change mtu manually for tunnel device
+ *   @dev: virtual device associated with tunnel
+ *   @new_mtu: the new mtu
+ *
+ * Return:
+ *   0 on success,
+ *   %-EINVAL if mtu too small
+ **/
+
+static int
+ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
+{
+	struct ip6_tnl *tnl = netdev_priv(dev);
+
+	if (tnl->parms.proto == IPPROTO_IPIP) {
+		if (new_mtu < 68)
+			return -EINVAL;
+	} else {
+		if (new_mtu < IPV6_MIN_MTU)
+			return -EINVAL;
+	}
+	if (new_mtu > 0xFFF8 - dev->hard_header_len)
+		return -EINVAL;
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+int ip6_tnl_get_iflink(const struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+
+	return t->parms.link;
+}
+EXPORT_SYMBOL(ip6_tnl_get_iflink);
+
+static const struct net_device_ops ip6_tnl_netdev_ops = {
+	.ndo_init	= ip6_tnl_dev_init,
+	.ndo_uninit	= ip6_tnl_dev_uninit,
+	.ndo_start_xmit = ip6_tnl_xmit,
+	.ndo_do_ioctl	= ip6_tnl_ioctl,
+	.ndo_change_mtu = ip6_tnl_change_mtu,
+	.ndo_get_stats	= ip6_get_stats,
+	.ndo_get_iflink = ip6_tnl_get_iflink,
+};
+
+
+/**
+ * ip6_tnl_dev_setup - setup virtual tunnel device
+ *   @dev: virtual device associated with tunnel
+ *
+ * Description:
+ *   Initialize function pointers and device parameters
+ **/
+
+static void ip6_tnl_dev_setup(struct net_device *dev)
+{
+	struct ip6_tnl *t;
+
+	dev->netdev_ops = &ip6_tnl_netdev_ops;
+	dev->destructor = ip6_dev_free;
+
+	dev->type = ARPHRD_TUNNEL6;
+	dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr);
+	dev->mtu = ETH_DATA_LEN - sizeof(struct ipv6hdr);
+	t = netdev_priv(dev);
+	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+		dev->mtu -= 8;
+	dev->flags |= IFF_NOARP;
+	dev->addr_len = sizeof(struct in6_addr);
+	netif_keep_dst(dev);
+	/* This perm addr will be used as interface identifier by IPv6 */
+	dev->addr_assign_type = NET_ADDR_RANDOM;
+	eth_random_addr(dev->perm_addr);
+}
+
+
+/**
+ * ip6_tnl_dev_init_gen - general initializer for all tunnel devices
+ *   @dev: virtual device associated with tunnel
+ **/
+
+static inline int
+ip6_tnl_dev_init_gen(struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+
+	t->dev = dev;
+	t->net = dev_net(dev);
+	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+	return 0;
+}
+
+/**
+ * ip6_tnl_dev_init - initializer for all non fallback tunnel devices
+ *   @dev: virtual device associated with tunnel
+ **/
+
+static int ip6_tnl_dev_init(struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	int err = ip6_tnl_dev_init_gen(dev);
+
+	if (err)
+		return err;
+	ip6_tnl_link_config(t);
+	return 0;
+}
+
+/**
+ * ip6_fb_tnl_dev_init - initializer for fallback tunnel device
+ *   @dev: fallback device
+ *
+ * Return: 0
+ **/
+
+static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct net *net = dev_net(dev);
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+
+	t->parms.proto = IPPROTO_IPV6;
+	dev_hold(dev);
+
+	rcu_assign_pointer(ip6n->tnls_wc[0], t);
+	return 0;
+}
+
+static int ip6_tnl_validate(struct nlattr *tb[], struct nlattr *data[])
+{
+	u8 proto;
+
+	if (!data || !data[IFLA_IPTUN_PROTO])
+		return 0;
+
+	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
+	if (proto != IPPROTO_IPV6 &&
+	    proto != IPPROTO_IPIP &&
+	    proto != 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void ip6_tnl_netlink_parms(struct nlattr *data[],
+				  struct __ip6_tnl_parm *parms)
+{
+	memset(parms, 0, sizeof(*parms));
+
+	if (!data)
+		return;
+
+	if (data[IFLA_IPTUN_LINK])
+		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
+
+	if (data[IFLA_IPTUN_LOCAL])
+		parms->laddr = nla_get_in6_addr(data[IFLA_IPTUN_LOCAL]);
+
+	if (data[IFLA_IPTUN_REMOTE])
+		parms->raddr = nla_get_in6_addr(data[IFLA_IPTUN_REMOTE]);
+
+	if (data[IFLA_IPTUN_TTL])
+		parms->hop_limit = nla_get_u8(data[IFLA_IPTUN_TTL]);
+
+	if (data[IFLA_IPTUN_ENCAP_LIMIT])
+		parms->encap_limit = nla_get_u8(data[IFLA_IPTUN_ENCAP_LIMIT]);
+
+	if (data[IFLA_IPTUN_FLOWINFO])
+		parms->flowinfo = nla_get_be32(data[IFLA_IPTUN_FLOWINFO]);
+
+	if (data[IFLA_IPTUN_FLAGS])
+		parms->flags = nla_get_u32(data[IFLA_IPTUN_FLAGS]);
+
+	if (data[IFLA_IPTUN_PROTO])
+		parms->proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
+}
+
+static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
+			   struct nlattr *tb[], struct nlattr *data[])
+{
+	struct net *net = dev_net(dev);
+	struct ip6_tnl *nt, *t;
+
+	nt = netdev_priv(dev);
+	ip6_tnl_netlink_parms(data, &nt->parms);
+
+	t = ip6_tnl_locate(net, &nt->parms, 0);
+	if (!IS_ERR(t))
+		return -EEXIST;
+
+	return ip6_tnl_create2(dev);
+}
+
+static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[],
+			      struct nlattr *data[])
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+	struct __ip6_tnl_parm p;
+	struct net *net = t->net;
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+
+	if (dev == ip6n->fb_tnl_dev)
+		return -EINVAL;
+
+	ip6_tnl_netlink_parms(data, &p);
+
+	t = ip6_tnl_locate(net, &p, 0);
+	if (!IS_ERR(t)) {
+		if (t->dev != dev)
+			return -EEXIST;
+	} else
+		t = netdev_priv(dev);
+
+	return ip6_tnl_update(t, &p);
+}
+
+static void ip6_tnl_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct net *net = dev_net(dev);
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+
+	if (dev != ip6n->fb_tnl_dev)
+		unregister_netdevice_queue(dev, head);
+}
+
+static size_t ip6_tnl_get_size(const struct net_device *dev)
+{
+	return
+		/* IFLA_IPTUN_LINK */
+		nla_total_size(4) +
+		/* IFLA_IPTUN_LOCAL */
+		nla_total_size(sizeof(struct in6_addr)) +
+		/* IFLA_IPTUN_REMOTE */
+		nla_total_size(sizeof(struct in6_addr)) +
+		/* IFLA_IPTUN_TTL */
+		nla_total_size(1) +
+		/* IFLA_IPTUN_ENCAP_LIMIT */
+		nla_total_size(1) +
+		/* IFLA_IPTUN_FLOWINFO */
+		nla_total_size(4) +
+		/* IFLA_IPTUN_FLAGS */
+		nla_total_size(4) +
+		/* IFLA_IPTUN_PROTO */
+		nla_total_size(1) +
+		0;
+}
+
+static int ip6_tnl_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	struct ip6_tnl *tunnel = netdev_priv(dev);
+	struct __ip6_tnl_parm *parm = &tunnel->parms;
+
+	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
+	    nla_put_in6_addr(skb, IFLA_IPTUN_LOCAL, &parm->laddr) ||
+	    nla_put_in6_addr(skb, IFLA_IPTUN_REMOTE, &parm->raddr) ||
+	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->hop_limit) ||
+	    nla_put_u8(skb, IFLA_IPTUN_ENCAP_LIMIT, parm->encap_limit) ||
+	    nla_put_be32(skb, IFLA_IPTUN_FLOWINFO, parm->flowinfo) ||
+	    nla_put_u32(skb, IFLA_IPTUN_FLAGS, parm->flags) ||
+	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto))
+		goto nla_put_failure;
+	return 0;
+
+nla_put_failure:
+	return -EMSGSIZE;
+}
+
+struct net *ip6_tnl_get_link_net(const struct net_device *dev)
+{
+	struct ip6_tnl *tunnel = netdev_priv(dev);
+
+	return tunnel->net;
+}
+EXPORT_SYMBOL(ip6_tnl_get_link_net);
+
+static const struct nla_policy ip6_tnl_policy[IFLA_IPTUN_MAX + 1] = {
+	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
+	[IFLA_IPTUN_LOCAL]		= { .len = sizeof(struct in6_addr) },
+	[IFLA_IPTUN_REMOTE]		= { .len = sizeof(struct in6_addr) },
+	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
+	[IFLA_IPTUN_ENCAP_LIMIT]	= { .type = NLA_U8 },
+	[IFLA_IPTUN_FLOWINFO]		= { .type = NLA_U32 },
+	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U32 },
+	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
+};
+
+static struct rtnl_link_ops ip6_link_ops __read_mostly = {
+	.kind		= "ip6tnl",
+	.maxtype	= IFLA_IPTUN_MAX,
+	.policy		= ip6_tnl_policy,
+	.priv_size	= sizeof(struct ip6_tnl),
+	.setup		= ip6_tnl_dev_setup,
+	.validate	= ip6_tnl_validate,
+	.newlink	= ip6_tnl_newlink,
+	.changelink	= ip6_tnl_changelink,
+	.dellink	= ip6_tnl_dellink,
+	.get_size	= ip6_tnl_get_size,
+	.fill_info	= ip6_tnl_fill_info,
+	.get_link_net	= ip6_tnl_get_link_net,
+};
+
+static struct xfrm6_tunnel ip4ip6_handler __read_mostly = {
+	.handler	= ip4ip6_rcv,
+	.err_handler	= ip4ip6_err,
+	.priority	=	1,
+};
+
+static struct xfrm6_tunnel ip6ip6_handler __read_mostly = {
+	.handler	= ip6ip6_rcv,
+	.err_handler	= ip6ip6_err,
+	.priority	=	1,
+};
+
+static void __net_exit ip6_tnl_destroy_tunnels(struct net *net)
+{
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	struct net_device *dev, *aux;
+	int h;
+	struct ip6_tnl *t;
+	LIST_HEAD(list);
+
+	for_each_netdev_safe(net, dev, aux)
+		if (dev->rtnl_link_ops == &ip6_link_ops)
+			unregister_netdevice_queue(dev, &list);
+
+	for (h = 0; h < HASH_SIZE; h++) {
+		t = rtnl_dereference(ip6n->tnls_r_l[h]);
+		while (t) {
+			/* If dev is in the same netns, it has already
+			 * been added to the list by the previous loop.
+			 */
+			if (!net_eq(dev_net(t->dev), net))
+				unregister_netdevice_queue(t->dev, &list);
+			t = rtnl_dereference(t->next);
+		}
+	}
+
+	unregister_netdevice_many(&list);
+}
+
+static int __net_init ip6_tnl_init_net(struct net *net)
+{
+	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	struct ip6_tnl *t = NULL;
+	int err;
+
+	ip6n->tnls[0] = ip6n->tnls_wc;
+	ip6n->tnls[1] = ip6n->tnls_r_l;
+
+	err = -ENOMEM;
+	ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
+					NET_NAME_UNKNOWN, ip6_tnl_dev_setup);
+
+	if (!ip6n->fb_tnl_dev)
+		goto err_alloc_dev;
+	dev_net_set(ip6n->fb_tnl_dev, net);
+	ip6n->fb_tnl_dev->rtnl_link_ops = &ip6_link_ops;
+	/* FB netdevice is special: we have one, and only one per netns.
+	 * Allowing to move it to another netns is clearly unsafe.
+	 */
+	ip6n->fb_tnl_dev->features |= NETIF_F_NETNS_LOCAL;
+
+	err = ip6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
+	if (err < 0)
+		goto err_register;
+
+	err = register_netdev(ip6n->fb_tnl_dev);
+	if (err < 0)
+		goto err_register;
+
+	t = netdev_priv(ip6n->fb_tnl_dev);
+
+	strcpy(t->parms.name, ip6n->fb_tnl_dev->name);
+	return 0;
+
+err_register:
+	ip6_dev_free(ip6n->fb_tnl_dev);
+err_alloc_dev:
+	return err;
+}
+
+static void __net_exit ip6_tnl_exit_net(struct net *net)
+{
+	rtnl_lock();
+	ip6_tnl_destroy_tunnels(net);
+	rtnl_unlock();
+}
+
+static struct pernet_operations ip6_tnl_net_ops = {
+	.init = ip6_tnl_init_net,
+	.exit = ip6_tnl_exit_net,
+	.id   = &ip6_tnl_net_id,
+	.size = sizeof(struct ip6_tnl_net),
+};
+
+/**
+ * ip6_tunnel_init - register protocol and reserve needed resources
+ *
+ * Return: 0 on success
+ **/
+
+static int __init ip6_tunnel_init(void)
+{
+	int  err;
+
+	err = register_pernet_device(&ip6_tnl_net_ops);
+	if (err < 0)
+		goto out_pernet;
+
+	err = xfrm6_tunnel_register(&ip4ip6_handler, AF_INET);
+	if (err < 0) {
+		pr_err("%s: can't register ip4ip6\n", __func__);
+		goto out_ip4ip6;
+	}
+
+	err = xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6);
+	if (err < 0) {
+		pr_err("%s: can't register ip6ip6\n", __func__);
+		goto out_ip6ip6;
+	}
+	err = rtnl_link_register(&ip6_link_ops);
+	if (err < 0)
+		goto rtnl_link_failed;
+
+	return 0;
+
+rtnl_link_failed:
+	xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6);
+out_ip6ip6:
+	xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
+out_ip4ip6:
+	unregister_pernet_device(&ip6_tnl_net_ops);
+out_pernet:
+	return err;
+}
+
+/**
+ * ip6_tunnel_cleanup - free resources and unregister protocol
+ **/
+
+static void __exit ip6_tunnel_cleanup(void)
+{
+	rtnl_link_unregister(&ip6_link_ops);
+	if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))
+		pr_info("%s: can't deregister ip4ip6\n", __func__);
+
+	if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))
+		pr_info("%s: can't deregister ip6ip6\n", __func__);
+
+	unregister_pernet_device(&ip6_tnl_net_ops);
+}
+
+module_init(ip6_tunnel_init);
+module_exit(ip6_tunnel_cleanup);