1 files changed, 912 insertions, 0 deletions

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
new file mode 100644
index 00000000..6f06f7f3
--- /dev/null
+++ b/net/ipv4/ipip.c
@@ -0,0 +1,912 @@
+/*
+ *	Linux NET3:	IP/IP protocol decoder.
+ *
+ *	Authors:
+ *		Sam Lantinga (slouken@cs.ucdavis.edu)  02/01/95
+ *
+ *	Fixes:
+ *		Alan Cox	:	Merged and made usable non modular (its so tiny its silly as
+ *					a module taking up 2 pages).
+ *		Alan Cox	: 	Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph)
+ *					to keep ip_forward happy.
+ *		Alan Cox	:	More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8).
+ *		Kai Schulte	:	Fixed #defines for IP_FIREWALL->FIREWALL
+ *              David Woodhouse :       Perform some basic ICMP handling.
+ *                                      IPIP Routing without decapsulation.
+ *              Carlos Picoto   :       GRE over IP support
+ *		Alexey Kuznetsov:	Reworked. Really, now it is truncated version of ipv4/ip_gre.c.
+ *					I do not want to merge them together.
+ *
+ *	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.
+ *
+ */
+
+/* tunnel.c: an IP tunnel driver
+
+	The purpose of this driver is to provide an IP tunnel through
+	which you can tunnel network traffic transparently across subnets.
+
+	This was written by looking at Nick Holloway's dummy driver
+	Thanks for the great code!
+
+		-Sam Lantinga	(slouken@cs.ucdavis.edu)  02/01/95
+
+	Minor tweaks:
+		Cleaned up the code a little and added some pre-1.3.0 tweaks.
+		dev->hard_header/hard_header_len changed to use no headers.
+		Comments/bracketing tweaked.
+		Made the tunnels use dev->name not tunnel: when error reporting.
+		Added tx_dropped stat
+
+		-Alan Cox	(alan@lxorguk.ukuu.org.uk) 21 March 95
+
+	Reworked:
+		Changed to tunnel to destination gateway in addition to the
+			tunnel's pointopoint address
+		Almost completely rewritten
+		Note:  There is currently no firewall or ICMP handling done.
+
+		-Sam Lantinga	(slouken@cs.ucdavis.edu) 02/13/96
+
+*/
+
+/* Things I wish I had known when writing the tunnel driver:
+
+	When the tunnel_xmit() function is called, the skb contains the
+	packet to be sent (plus a great deal of extra info), and dev
+	contains the tunnel device that _we_ are.
+
+	When we are passed a packet, we are expected to fill in the
+	source address with our source IP address.
+
+	What is the proper way to allocate, copy and free a buffer?
+	After you allocate it, it is a "0 length" chunk of memory
+	starting at zero.  If you want to add headers to the buffer
+	later, you'll have to call "skb_reserve(skb, amount)" with
+	the amount of memory you want reserved.  Then, you call
+	"skb_put(skb, amount)" with the amount of space you want in
+	the buffer.  skb_put() returns a pointer to the top (#0) of
+	that buffer.  skb->len is set to the amount of space you have
+	"allocated" with skb_put().  You can then write up to skb->len
+	bytes to that buffer.  If you need more, you can call skb_put()
+	again with the additional amount of space you need.  You can
+	find out how much more space you can allocate by calling
+	"skb_tailroom(skb)".
+	Now, to add header space, call "skb_push(skb, header_len)".
+	This creates space at the beginning of the buffer and returns
+	a pointer to this new space.  If later you need to strip a
+	header from a buffer, call "skb_pull(skb, header_len)".
+	skb_headroom() will return how much space is left at the top
+	of the buffer (before the main data).  Remember, this headroom
+	space must be reserved before the skb_put() function is called.
+	*/
+
+/*
+   This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c
+
+   For comments look at net/ipv4/ip_gre.c --ANK
+ */
+
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <asm/uaccess.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/if_arp.h>
+#include <linux/mroute.h>
+#include <linux/init.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/if_ether.h>
+
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/ipip.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+#define HASH_SIZE  16
+#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
+
+static int ipip_net_id __read_mostly;
+struct ipip_net {
+	struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
+	struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
+	struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
+	struct ip_tunnel __rcu *tunnels_wc[1];
+	struct ip_tunnel __rcu **tunnels[4];
+
+	struct net_device *fb_tunnel_dev;
+};
+
+static int ipip_tunnel_init(struct net_device *dev);
+static void ipip_tunnel_setup(struct net_device *dev);
+static void ipip_dev_free(struct net_device *dev);
+
+/*
+ * Locking : hash tables are protected by RCU and RTNL
+ */
+
+#define for_each_ip_tunnel_rcu(start) \
+	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
+
+/* often modified stats are per cpu, other are shared (netdev->stats) */
+struct pcpu_tstats {
+	unsigned long	rx_packets;
+	unsigned long	rx_bytes;
+	unsigned long	tx_packets;
+	unsigned long	tx_bytes;
+};
+
+static struct net_device_stats *ipip_get_stats(struct net_device *dev)
+{
+	struct pcpu_tstats sum = { 0 };
+	int i;
+
+	for_each_possible_cpu(i) {
+		const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
+
+		sum.rx_packets += tstats->rx_packets;
+		sum.rx_bytes   += tstats->rx_bytes;
+		sum.tx_packets += tstats->tx_packets;
+		sum.tx_bytes   += tstats->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;
+}
+
+static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
+		__be32 remote, __be32 local)
+{
+	unsigned int h0 = HASH(remote);
+	unsigned int h1 = HASH(local);
+	struct ip_tunnel *t;
+	struct ipip_net *ipn = net_generic(net, ipip_net_id);
+
+	for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
+		if (local == t->parms.iph.saddr &&
+		    remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
+			return t;
+
+	for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
+		if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
+			return t;
+
+	for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
+		if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
+			return t;
+
+	t = rcu_dereference(ipn->tunnels_wc[0]);
+	if (t && (t->dev->flags&IFF_UP))
+		return t;
+	return NULL;
+}
+
+static struct ip_tunnel __rcu **__ipip_bucket(struct ipip_net *ipn,
+		struct ip_tunnel_parm *parms)
+{
+	__be32 remote = parms->iph.daddr;
+	__be32 local = parms->iph.saddr;
+	unsigned int h = 0;
+	int prio = 0;
+
+	if (remote) {
+		prio |= 2;
+		h ^= HASH(remote);
+	}
+	if (local) {
+		prio |= 1;
+		h ^= HASH(local);
+	}
+	return &ipn->tunnels[prio][h];
+}
+
+static inline struct ip_tunnel __rcu **ipip_bucket(struct ipip_net *ipn,
+		struct ip_tunnel *t)
+{
+	return __ipip_bucket(ipn, &t->parms);
+}
+
+static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
+{
+	struct ip_tunnel __rcu **tp;
+	struct ip_tunnel *iter;
+
+	for (tp = ipip_bucket(ipn, t);
+	     (iter = rtnl_dereference(*tp)) != NULL;
+	     tp = &iter->next) {
+		if (t == iter) {
+			rcu_assign_pointer(*tp, t->next);
+			break;
+		}
+	}
+}
+
+static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
+{
+	struct ip_tunnel __rcu **tp = ipip_bucket(ipn, t);
+
+	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
+	rcu_assign_pointer(*tp, t);
+}
+
+static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
+		struct ip_tunnel_parm *parms, int create)
+{
+	__be32 remote = parms->iph.daddr;
+	__be32 local = parms->iph.saddr;
+	struct ip_tunnel *t, *nt;
+	struct ip_tunnel __rcu **tp;
+	struct net_device *dev;
+	char name[IFNAMSIZ];
+	struct ipip_net *ipn = net_generic(net, ipip_net_id);
+
+	for (tp = __ipip_bucket(ipn, parms);
+		 (t = rtnl_dereference(*tp)) != NULL;
+		 tp = &t->next) {
+		if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
+			return t;
+	}
+	if (!create)
+		return NULL;
+
+	if (parms->name[0])
+		strlcpy(name, parms->name, IFNAMSIZ);
+	else
+		strcpy(name, "tunl%d");
+
+	dev = alloc_netdev(sizeof(*t), name, ipip_tunnel_setup);
+	if (dev == NULL)
+		return NULL;
+
+	dev_net_set(dev, net);
+
+	nt = netdev_priv(dev);
+	nt->parms = *parms;
+
+	if (ipip_tunnel_init(dev) < 0)
+		goto failed_free;
+
+	if (register_netdevice(dev) < 0)
+		goto failed_free;
+
+	strcpy(nt->parms.name, dev->name);
+
+	dev_hold(dev);
+	ipip_tunnel_link(ipn, nt);
+	return nt;
+
+failed_free:
+	ipip_dev_free(dev);
+	return NULL;
+}
+
+/* called with RTNL */
+static void ipip_tunnel_uninit(struct net_device *dev)
+{
+	struct net *net = dev_net(dev);
+	struct ipip_net *ipn = net_generic(net, ipip_net_id);
+
+	if (dev == ipn->fb_tunnel_dev)
+		rcu_assign_pointer(ipn->tunnels_wc[0], NULL);
+	else
+		ipip_tunnel_unlink(ipn, netdev_priv(dev));
+	dev_put(dev);
+}
+
+static int ipip_err(struct sk_buff *skb, u32 info)
+{
+
+/* All the routers (except for Linux) return only
+   8 bytes of packet payload. It means, that precise relaying of
+   ICMP in the real Internet is absolutely infeasible.
+ */
+	const struct iphdr *iph = (const struct iphdr *)skb->data;
+	const int type = icmp_hdr(skb)->type;
+	const int code = icmp_hdr(skb)->code;
+	struct ip_tunnel *t;
+	int err;
+
+	switch (type) {
+	default:
+	case ICMP_PARAMETERPROB:
+		return 0;
+
+	case ICMP_DEST_UNREACH:
+		switch (code) {
+		case ICMP_SR_FAILED:
+		case ICMP_PORT_UNREACH:
+			/* Impossible event. */
+			return 0;
+		case ICMP_FRAG_NEEDED:
+			/* Soft state for pmtu is maintained by IP core. */
+			return 0;
+		default:
+			/* All others are translated to HOST_UNREACH.
+			   rfc2003 contains "deep thoughts" about NET_UNREACH,
+			   I believe they are just ether pollution. --ANK
+			 */
+			break;
+		}
+		break;
+	case ICMP_TIME_EXCEEDED:
+		if (code != ICMP_EXC_TTL)
+			return 0;
+		break;
+	}
+
+	err = -ENOENT;
+
+	rcu_read_lock();
+	t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
+	if (t == NULL || t->parms.iph.daddr == 0)
+		goto out;
+
+	err = 0;
+	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
+		goto out;
+
+	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
+		t->err_count++;
+	else
+		t->err_count = 1;
+	t->err_time = jiffies;
+out:
+	rcu_read_unlock();
+	return err;
+}
+
+static inline void ipip_ecn_decapsulate(const struct iphdr *outer_iph,
+					struct sk_buff *skb)
+{
+	struct iphdr *inner_iph = ip_hdr(skb);
+
+	if (INET_ECN_is_ce(outer_iph->tos))
+		IP_ECN_set_ce(inner_iph);
+}
+
+static int ipip_rcv(struct sk_buff *skb)
+{
+	struct ip_tunnel *tunnel;
+	const struct iphdr *iph = ip_hdr(skb);
+
+	rcu_read_lock();
+	tunnel = ipip_tunnel_lookup(dev_net(skb->dev), iph->saddr, iph->daddr);
+	if (tunnel != NULL) {
+		struct pcpu_tstats *tstats;
+
+		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
+			rcu_read_unlock();
+			kfree_skb(skb);
+			return 0;
+		}
+
+		secpath_reset(skb);
+
+		skb->mac_header = skb->network_header;
+		skb_reset_network_header(skb);
+		skb->protocol = htons(ETH_P_IP);
+		skb->pkt_type = PACKET_HOST;
+
+		tstats = this_cpu_ptr(tunnel->dev->tstats);
+		tstats->rx_packets++;
+		tstats->rx_bytes += skb->len;
+
+		__skb_tunnel_rx(skb, tunnel->dev);
+
+		ipip_ecn_decapsulate(iph, skb);
+
+		netif_rx(skb);
+
+		rcu_read_unlock();
+		return 0;
+	}
+	rcu_read_unlock();
+
+	return -1;
+}
+
+/*
+ *	This function assumes it is being called from dev_queue_xmit()
+ *	and that skb is filled properly by that function.
+ */
+
+static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct pcpu_tstats *tstats;
+	const struct iphdr  *tiph = &tunnel->parms.iph;
+	u8     tos = tunnel->parms.iph.tos;
+	__be16 df = tiph->frag_off;
+	struct rtable *rt;     			/* Route to the other host */
+	struct net_device *tdev;		/* Device to other host */
+	const struct iphdr  *old_iph = ip_hdr(skb);
+	struct iphdr  *iph;			/* Our new IP header */
+	unsigned int max_headroom;		/* The extra header space needed */
+	__be32 dst = tiph->daddr;
+	struct flowi4 fl4;
+	int    mtu;
+
+	if (skb->protocol != htons(ETH_P_IP))
+		goto tx_error;
+
+	if (tos & 1)
+		tos = old_iph->tos;
+
+	if (!dst) {
+		/* NBMA tunnel */
+		if ((rt = skb_rtable(skb)) == NULL) {
+			dev->stats.tx_fifo_errors++;
+			goto tx_error;
+		}
+		if ((dst = rt->rt_gateway) == 0)
+			goto tx_error_icmp;
+	}
+
+	rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
+				   dst, tiph->saddr,
+				   0, 0,
+				   IPPROTO_IPIP, RT_TOS(tos),
+				   tunnel->parms.link);
+	if (IS_ERR(rt)) {
+		dev->stats.tx_carrier_errors++;
+		goto tx_error_icmp;
+	}
+	tdev = rt->dst.dev;
+
+	if (tdev == dev) {
+		ip_rt_put(rt);
+		dev->stats.collisions++;
+		goto tx_error;
+	}
+
+	df |= old_iph->frag_off & htons(IP_DF);
+
+	if (df) {
+		mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
+
+		if (mtu < 68) {
+			dev->stats.collisions++;
+			ip_rt_put(rt);
+			goto tx_error;
+		}
+
+		if (skb_dst(skb))
+			skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
+
+		if ((old_iph->frag_off & htons(IP_DF)) &&
+		    mtu < ntohs(old_iph->tot_len)) {
+			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+				  htonl(mtu));
+			ip_rt_put(rt);
+			goto tx_error;
+		}
+	}
+
+	if (tunnel->err_count > 0) {
+		if (time_before(jiffies,
+				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
+			tunnel->err_count--;
+			dst_link_failure(skb);
+		} else
+			tunnel->err_count = 0;
+	}
+
+	/*
+	 * Okay, now see if we can stuff it in the buffer as-is.
+	 */
+	max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
+
+	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
+	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
+		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
+		if (!new_skb) {
+			ip_rt_put(rt);
+			dev->stats.tx_dropped++;
+			dev_kfree_skb(skb);
+			return NETDEV_TX_OK;
+		}
+		if (skb->sk)
+			skb_set_owner_w(new_skb, skb->sk);
+		dev_kfree_skb(skb);
+		skb = new_skb;
+		old_iph = ip_hdr(skb);
+	}
+
+	skb->transport_header = skb->network_header;
+	skb_push(skb, sizeof(struct iphdr));
+	skb_reset_network_header(skb);
+	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
+			      IPSKB_REROUTED);
+	skb_dst_drop(skb);
+	skb_dst_set(skb, &rt->dst);
+
+	/*
+	 *	Push down and install the IPIP header.
+	 */
+
+	iph 			=	ip_hdr(skb);
+	iph->version		=	4;
+	iph->ihl		=	sizeof(struct iphdr)>>2;
+	iph->frag_off		=	df;
+	iph->protocol		=	IPPROTO_IPIP;
+	iph->tos		=	INET_ECN_encapsulate(tos, old_iph->tos);
+	iph->daddr		=	fl4.daddr;
+	iph->saddr		=	fl4.saddr;
+
+	if ((iph->ttl = tiph->ttl) == 0)
+		iph->ttl	=	old_iph->ttl;
+
+	nf_reset(skb);
+	tstats = this_cpu_ptr(dev->tstats);
+	__IPTUNNEL_XMIT(tstats, &dev->stats);
+	return NETDEV_TX_OK;
+
+tx_error_icmp:
+	dst_link_failure(skb);
+tx_error:
+	dev->stats.tx_errors++;
+	dev_kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+static void ipip_tunnel_bind_dev(struct net_device *dev)
+{
+	struct net_device *tdev = NULL;
+	struct ip_tunnel *tunnel;
+	const struct iphdr *iph;
+
+	tunnel = netdev_priv(dev);
+	iph = &tunnel->parms.iph;
+
+	if (iph->daddr) {
+		struct rtable *rt;
+		struct flowi4 fl4;
+
+		rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
+					   iph->daddr, iph->saddr,
+					   0, 0,
+					   IPPROTO_IPIP,
+					   RT_TOS(iph->tos),
+					   tunnel->parms.link);
+		if (!IS_ERR(rt)) {
+			tdev = rt->dst.dev;
+			ip_rt_put(rt);
+		}
+		dev->flags |= IFF_POINTOPOINT;
+	}
+
+	if (!tdev && tunnel->parms.link)
+		tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
+
+	if (tdev) {
+		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
+		dev->mtu = tdev->mtu - sizeof(struct iphdr);
+	}
+	dev->iflink = tunnel->parms.link;
+}
+
+static int
+ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	int err = 0;
+	struct ip_tunnel_parm p;
+	struct ip_tunnel *t;
+	struct net *net = dev_net(dev);
+	struct ipip_net *ipn = net_generic(net, ipip_net_id);
+
+	switch (cmd) {
+	case SIOCGETTUNNEL:
+		t = NULL;
+		if (dev == ipn->fb_tunnel_dev) {
+			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
+				err = -EFAULT;
+				break;
+			}
+			t = ipip_tunnel_locate(net, &p, 0);
+		}
+		if (t == NULL)
+			t = netdev_priv(dev);
+		memcpy(&p, &t->parms, sizeof(p));
+		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
+			err = -EFAULT;
+		break;
+
+	case SIOCADDTUNNEL:
+	case SIOCCHGTUNNEL:
+		err = -EPERM;
+		if (!capable(CAP_NET_ADMIN))
+			goto done;
+
+		err = -EFAULT;
+		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+			goto done;
+
+		err = -EINVAL;
+		if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
+		    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
+			goto done;
+		if (p.iph.ttl)
+			p.iph.frag_off |= htons(IP_DF);
+
+		t = ipip_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
+
+		if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
+			if (t != NULL) {
+				if (t->dev != dev) {
+					err = -EEXIST;
+					break;
+				}
+			} else {
+				if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
+				    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
+					err = -EINVAL;
+					break;
+				}
+				t = netdev_priv(dev);
+				ipip_tunnel_unlink(ipn, t);
+				synchronize_net();
+				t->parms.iph.saddr = p.iph.saddr;
+				t->parms.iph.daddr = p.iph.daddr;
+				memcpy(dev->dev_addr, &p.iph.saddr, 4);
+				memcpy(dev->broadcast, &p.iph.daddr, 4);
+				ipip_tunnel_link(ipn, t);
+				netdev_state_change(dev);
+			}
+		}
+
+		if (t) {
+			err = 0;
+			if (cmd == SIOCCHGTUNNEL) {
+				t->parms.iph.ttl = p.iph.ttl;
+				t->parms.iph.tos = p.iph.tos;
+				t->parms.iph.frag_off = p.iph.frag_off;
+				if (t->parms.link != p.link) {
+					t->parms.link = p.link;
+					ipip_tunnel_bind_dev(dev);
+					netdev_state_change(dev);
+				}
+			}
+			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
+				err = -EFAULT;
+		} else
+			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
+		break;
+
+	case SIOCDELTUNNEL:
+		err = -EPERM;
+		if (!capable(CAP_NET_ADMIN))
+			goto done;
+
+		if (dev == ipn->fb_tunnel_dev) {
+			err = -EFAULT;
+			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+				goto done;
+			err = -ENOENT;
+			if ((t = ipip_tunnel_locate(net, &p, 0)) == NULL)
+				goto done;
+			err = -EPERM;
+			if (t->dev == ipn->fb_tunnel_dev)
+				goto done;
+			dev = t->dev;
+		}
+		unregister_netdevice(dev);
+		err = 0;
+		break;
+
+	default:
+		err = -EINVAL;
+	}
+
+done:
+	return err;
+}
+
+static int ipip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
+		return -EINVAL;
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops ipip_netdev_ops = {
+	.ndo_uninit	= ipip_tunnel_uninit,
+	.ndo_start_xmit	= ipip_tunnel_xmit,
+	.ndo_do_ioctl	= ipip_tunnel_ioctl,
+	.ndo_change_mtu	= ipip_tunnel_change_mtu,
+	.ndo_get_stats  = ipip_get_stats,
+};
+
+static void ipip_dev_free(struct net_device *dev)
+{
+	free_percpu(dev->tstats);
+	free_netdev(dev);
+}
+
+static void ipip_tunnel_setup(struct net_device *dev)
+{
+	dev->netdev_ops		= &ipip_netdev_ops;
+	dev->destructor		= ipip_dev_free;
+
+	dev->type		= ARPHRD_TUNNEL;
+	dev->hard_header_len 	= LL_MAX_HEADER + sizeof(struct iphdr);
+	dev->mtu		= ETH_DATA_LEN - sizeof(struct iphdr);
+	dev->flags		= IFF_NOARP;
+	dev->iflink		= 0;
+	dev->addr_len		= 4;
+	dev->features		|= NETIF_F_NETNS_LOCAL;
+	dev->features		|= NETIF_F_LLTX;
+	dev->priv_flags		&= ~IFF_XMIT_DST_RELEASE;
+}
+
+static int ipip_tunnel_init(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+
+	tunnel->dev = dev;
+
+	memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
+	memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
+
+	ipip_tunnel_bind_dev(dev);
+
+	dev->tstats = alloc_percpu(struct pcpu_tstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int __net_init ipip_fb_tunnel_init(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct iphdr *iph = &tunnel->parms.iph;
+	struct ipip_net *ipn = net_generic(dev_net(dev), ipip_net_id);
+
+	tunnel->dev = dev;
+	strcpy(tunnel->parms.name, dev->name);
+
+	iph->version		= 4;
+	iph->protocol		= IPPROTO_IPIP;
+	iph->ihl		= 5;
+
+	dev->tstats = alloc_percpu(struct pcpu_tstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+
+	dev_hold(dev);
+	rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
+	return 0;
+}
+
+static struct xfrm_tunnel ipip_handler __read_mostly = {
+	.handler	=	ipip_rcv,
+	.err_handler	=	ipip_err,
+	.priority	=	1,
+};
+
+static const char banner[] __initconst =
+	KERN_INFO "IPv4 over IPv4 tunneling driver\n";
+
+static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
+{
+	int prio;
+
+	for (prio = 1; prio < 4; prio++) {
+		int h;
+		for (h = 0; h < HASH_SIZE; h++) {
+			struct ip_tunnel *t;
+
+			t = rtnl_dereference(ipn->tunnels[prio][h]);
+			while (t != NULL) {
+				unregister_netdevice_queue(t->dev, head);
+				t = rtnl_dereference(t->next);
+			}
+		}
+	}
+}
+
+static int __net_init ipip_init_net(struct net *net)
+{
+	struct ipip_net *ipn = net_generic(net, ipip_net_id);
+	struct ip_tunnel *t;
+	int err;
+
+	ipn->tunnels[0] = ipn->tunnels_wc;
+	ipn->tunnels[1] = ipn->tunnels_l;
+	ipn->tunnels[2] = ipn->tunnels_r;
+	ipn->tunnels[3] = ipn->tunnels_r_l;
+
+	ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
+					   "tunl0",
+					   ipip_tunnel_setup);
+	if (!ipn->fb_tunnel_dev) {
+		err = -ENOMEM;
+		goto err_alloc_dev;
+	}
+	dev_net_set(ipn->fb_tunnel_dev, net);
+
+	err = ipip_fb_tunnel_init(ipn->fb_tunnel_dev);
+	if (err)
+		goto err_reg_dev;
+
+	if ((err = register_netdev(ipn->fb_tunnel_dev)))
+		goto err_reg_dev;
+
+	t = netdev_priv(ipn->fb_tunnel_dev);
+
+	strcpy(t->parms.name, ipn->fb_tunnel_dev->name);
+	return 0;
+
+err_reg_dev:
+	ipip_dev_free(ipn->fb_tunnel_dev);
+err_alloc_dev:
+	/* nothing */
+	return err;
+}
+
+static void __net_exit ipip_exit_net(struct net *net)
+{
+	struct ipip_net *ipn = net_generic(net, ipip_net_id);
+	LIST_HEAD(list);
+
+	rtnl_lock();
+	ipip_destroy_tunnels(ipn, &list);
+	unregister_netdevice_queue(ipn->fb_tunnel_dev, &list);
+	unregister_netdevice_many(&list);
+	rtnl_unlock();
+}
+
+static struct pernet_operations ipip_net_ops = {
+	.init = ipip_init_net,
+	.exit = ipip_exit_net,
+	.id   = &ipip_net_id,
+	.size = sizeof(struct ipip_net),
+};
+
+static int __init ipip_init(void)
+{
+	int err;
+
+	printk(banner);
+
+	err = register_pernet_device(&ipip_net_ops);
+	if (err < 0)
+		return err;
+	err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
+	if (err < 0) {
+		unregister_pernet_device(&ipip_net_ops);
+		printk(KERN_INFO "ipip init: can't register tunnel\n");
+	}
+	return err;
+}
+
+static void __exit ipip_fini(void)
+{
+	if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
+		printk(KERN_INFO "ipip close: can't deregister tunnel\n");
+
+	unregister_pernet_device(&ipip_net_ops);
+}
+
+module_init(ipip_init);
+module_exit(ipip_fini);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETDEV("tunl0");