Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

1 files changed, 1306 insertions, 0 deletions

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
new file mode 100644
index 00000000..c4ffd174
--- /dev/null
+++ b/net/ipv6/sit.c
@@ -0,0 +1,1306 @@
+/*
+ *	IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
+ *	Linux INET6 implementation
+ *
+ *	Authors:
+ *	Pedro Roque		<roque@di.fc.ul.pt>
+ *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
+ *
+ *	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.
+ *
+ *	Changes:
+ * Roger Venning <r.venning@telstra.com>:	6to4 support
+ * Nate Thompson <nate@thebog.net>:		6to4 support
+ * Fred Templin <fred.l.templin@boeing.com>:	isatap support
+ */
+
+#include <linux/module.h>
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/in6.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/icmp.h>
+#include <linux/slab.h>
+#include <asm/uaccess.h>
+#include <linux/init.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/if_ether.h>
+
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+#include <net/ip.h>
+#include <net/udp.h>
+#include <net/icmp.h>
+#include <net/ipip.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/dsfield.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+/*
+   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
+
+   For comments look at net/ipv4/ip_gre.c --ANK
+ */
+
+#define HASH_SIZE  16
+#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
+
+static int ipip6_tunnel_init(struct net_device *dev);
+static void ipip6_tunnel_setup(struct net_device *dev);
+static void ipip6_dev_free(struct net_device *dev);
+
+static int sit_net_id __read_mostly;
+struct sit_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;
+};
+
+/*
+ * 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;
+} __attribute__((aligned(4*sizeof(unsigned long))));
+
+static struct net_device_stats *ipip6_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;
+}
+/*
+ * Must be invoked with rcu_read_lock
+ */
+static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
+		struct net_device *dev, __be32 remote, __be32 local)
+{
+	unsigned int h0 = HASH(remote);
+	unsigned int h1 = HASH(local);
+	struct ip_tunnel *t;
+	struct sit_net *sitn = net_generic(net, sit_net_id);
+
+	for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
+		if (local == t->parms.iph.saddr &&
+		    remote == t->parms.iph.daddr &&
+		    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+	for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
+		if (remote == t->parms.iph.daddr &&
+		    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+	for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
+		if (local == t->parms.iph.saddr &&
+		    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+	t = rcu_dereference(sitn->tunnels_wc[0]);
+	if ((t != NULL) && (t->dev->flags & IFF_UP))
+		return t;
+	return NULL;
+}
+
+static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
+		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 &sitn->tunnels[prio][h];
+}
+
+static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
+		struct ip_tunnel *t)
+{
+	return __ipip6_bucket(sitn, &t->parms);
+}
+
+static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
+{
+	struct ip_tunnel __rcu **tp;
+	struct ip_tunnel *iter;
+
+	for (tp = ipip6_bucket(sitn, t);
+	     (iter = rtnl_dereference(*tp)) != NULL;
+	     tp = &iter->next) {
+		if (t == iter) {
+			rcu_assign_pointer(*tp, t->next);
+			break;
+		}
+	}
+}
+
+static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
+{
+	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
+
+	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
+	rcu_assign_pointer(*tp, t);
+}
+
+static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
+{
+#ifdef CONFIG_IPV6_SIT_6RD
+	struct ip_tunnel *t = netdev_priv(dev);
+
+	if (t->dev == sitn->fb_tunnel_dev) {
+		ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
+		t->ip6rd.relay_prefix = 0;
+		t->ip6rd.prefixlen = 16;
+		t->ip6rd.relay_prefixlen = 0;
+	} else {
+		struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
+		memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
+	}
+#endif
+}
+
+static struct ip_tunnel *ipip6_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 sit_net *sitn = net_generic(net, sit_net_id);
+
+	for (tp = __ipip6_bucket(sitn, parms);
+	    (t = rtnl_dereference(*tp)) != NULL;
+	     tp = &t->next) {
+		if (local == t->parms.iph.saddr &&
+		    remote == t->parms.iph.daddr &&
+		    parms->link == t->parms.link) {
+			if (create)
+				return NULL;
+			else
+				return t;
+		}
+	}
+	if (!create)
+		goto failed;
+
+	if (parms->name[0])
+		strlcpy(name, parms->name, IFNAMSIZ);
+	else
+		strcpy(name, "sit%d");
+
+	dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
+	if (dev == NULL)
+		return NULL;
+
+	dev_net_set(dev, net);
+
+	nt = netdev_priv(dev);
+
+	nt->parms = *parms;
+	if (ipip6_tunnel_init(dev) < 0)
+		goto failed_free;
+	ipip6_tunnel_clone_6rd(dev, sitn);
+
+	if (parms->i_flags & SIT_ISATAP)
+		dev->priv_flags |= IFF_ISATAP;
+
+	if (register_netdevice(dev) < 0)
+		goto failed_free;
+
+	strcpy(nt->parms.name, dev->name);
+
+	dev_hold(dev);
+
+	ipip6_tunnel_link(sitn, nt);
+	return nt;
+
+failed_free:
+	ipip6_dev_free(dev);
+failed:
+	return NULL;
+}
+
+#define for_each_prl_rcu(start)			\
+	for (prl = rcu_dereference(start);	\
+	     prl;				\
+	     prl = rcu_dereference(prl->next))
+
+static struct ip_tunnel_prl_entry *
+__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
+{
+	struct ip_tunnel_prl_entry *prl;
+
+	for_each_prl_rcu(t->prl)
+		if (prl->addr == addr)
+			break;
+	return prl;
+
+}
+
+static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
+				struct ip_tunnel_prl __user *a)
+{
+	struct ip_tunnel_prl kprl, *kp;
+	struct ip_tunnel_prl_entry *prl;
+	unsigned int cmax, c = 0, ca, len;
+	int ret = 0;
+
+	if (copy_from_user(&kprl, a, sizeof(kprl)))
+		return -EFAULT;
+	cmax = kprl.datalen / sizeof(kprl);
+	if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
+		cmax = 1;
+
+	/* For simple GET or for root users,
+	 * we try harder to allocate.
+	 */
+	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
+		kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
+		NULL;
+
+	rcu_read_lock();
+
+	ca = t->prl_count < cmax ? t->prl_count : cmax;
+
+	if (!kp) {
+		/* We don't try hard to allocate much memory for
+		 * non-root users.
+		 * For root users, retry allocating enough memory for
+		 * the answer.
+		 */
+		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
+		if (!kp) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	c = 0;
+	for_each_prl_rcu(t->prl) {
+		if (c >= cmax)
+			break;
+		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
+			continue;
+		kp[c].addr = prl->addr;
+		kp[c].flags = prl->flags;
+		c++;
+		if (kprl.addr != htonl(INADDR_ANY))
+			break;
+	}
+out:
+	rcu_read_unlock();
+
+	len = sizeof(*kp) * c;
+	ret = 0;
+	if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
+		ret = -EFAULT;
+
+	kfree(kp);
+
+	return ret;
+}
+
+static int
+ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
+{
+	struct ip_tunnel_prl_entry *p;
+	int err = 0;
+
+	if (a->addr == htonl(INADDR_ANY))
+		return -EINVAL;
+
+	ASSERT_RTNL();
+
+	for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
+		if (p->addr == a->addr) {
+			if (chg) {
+				p->flags = a->flags;
+				goto out;
+			}
+			err = -EEXIST;
+			goto out;
+		}
+	}
+
+	if (chg) {
+		err = -ENXIO;
+		goto out;
+	}
+
+	p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
+	if (!p) {
+		err = -ENOBUFS;
+		goto out;
+	}
+
+	p->next = t->prl;
+	p->addr = a->addr;
+	p->flags = a->flags;
+	t->prl_count++;
+	rcu_assign_pointer(t->prl, p);
+out:
+	return err;
+}
+
+static void prl_list_destroy_rcu(struct rcu_head *head)
+{
+	struct ip_tunnel_prl_entry *p, *n;
+
+	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
+	do {
+		n = rcu_dereference_protected(p->next, 1);
+		kfree(p);
+		p = n;
+	} while (p);
+}
+
+static int
+ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
+{
+	struct ip_tunnel_prl_entry *x;
+	struct ip_tunnel_prl_entry __rcu **p;
+	int err = 0;
+
+	ASSERT_RTNL();
+
+	if (a && a->addr != htonl(INADDR_ANY)) {
+		for (p = &t->prl;
+		     (x = rtnl_dereference(*p)) != NULL;
+		     p = &x->next) {
+			if (x->addr == a->addr) {
+				*p = x->next;
+				kfree_rcu(x, rcu_head);
+				t->prl_count--;
+				goto out;
+			}
+		}
+		err = -ENXIO;
+	} else {
+		x = rtnl_dereference(t->prl);
+		if (x) {
+			t->prl_count = 0;
+			call_rcu(&x->rcu_head, prl_list_destroy_rcu);
+			t->prl = NULL;
+		}
+	}
+out:
+	return err;
+}
+
+static int
+isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
+{
+	struct ip_tunnel_prl_entry *p;
+	int ok = 1;
+
+	rcu_read_lock();
+	p = __ipip6_tunnel_locate_prl(t, iph->saddr);
+	if (p) {
+		if (p->flags & PRL_DEFAULT)
+			skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
+		else
+			skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
+	} else {
+		const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
+
+		if (ipv6_addr_is_isatap(addr6) &&
+		    (addr6->s6_addr32[3] == iph->saddr) &&
+		    ipv6_chk_prefix(addr6, t->dev))
+			skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
+		else
+			ok = 0;
+	}
+	rcu_read_unlock();
+	return ok;
+}
+
+static void ipip6_tunnel_uninit(struct net_device *dev)
+{
+	struct net *net = dev_net(dev);
+	struct sit_net *sitn = net_generic(net, sit_net_id);
+
+	if (dev == sitn->fb_tunnel_dev) {
+		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
+	} else {
+		ipip6_tunnel_unlink(sitn, netdev_priv(dev));
+		ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
+	}
+	dev_put(dev);
+}
+
+
+static int ipip6_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 = ipip6_tunnel_lookup(dev_net(skb->dev),
+				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 ipip6_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
+{
+	if (INET_ECN_is_ce(iph->tos))
+		IP6_ECN_set_ce(ipv6_hdr(skb));
+}
+
+static int ipip6_rcv(struct sk_buff *skb)
+{
+	const struct iphdr *iph;
+	struct ip_tunnel *tunnel;
+
+	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+		goto out;
+
+	iph = ip_hdr(skb);
+
+	rcu_read_lock();
+	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
+				     iph->saddr, iph->daddr);
+	if (tunnel != NULL) {
+		struct pcpu_tstats *tstats;
+
+		secpath_reset(skb);
+		skb->mac_header = skb->network_header;
+		skb_reset_network_header(skb);
+		IPCB(skb)->flags = 0;
+		skb->protocol = htons(ETH_P_IPV6);
+		skb->pkt_type = PACKET_HOST;
+
+		if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
+		    !isatap_chksrc(skb, iph, tunnel)) {
+			tunnel->dev->stats.rx_errors++;
+			rcu_read_unlock();
+			kfree_skb(skb);
+			return 0;
+		}
+
+		tstats = this_cpu_ptr(tunnel->dev->tstats);
+		tstats->rx_packets++;
+		tstats->rx_bytes += skb->len;
+
+		__skb_tunnel_rx(skb, tunnel->dev);
+
+		ipip6_ecn_decapsulate(iph, skb);
+
+		netif_rx(skb);
+
+		rcu_read_unlock();
+		return 0;
+	}
+
+	/* no tunnel matched,  let upstream know, ipsec may handle it */
+	rcu_read_unlock();
+	return 1;
+out:
+	kfree_skb(skb);
+	return 0;
+}
+
+/*
+ * Returns the embedded IPv4 address if the IPv6 address
+ * comes from 6rd / 6to4 (RFC 3056) addr space.
+ */
+static inline
+__be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
+{
+	__be32 dst = 0;
+
+#ifdef CONFIG_IPV6_SIT_6RD
+	if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
+			      tunnel->ip6rd.prefixlen)) {
+		unsigned int pbw0, pbi0;
+		int pbi1;
+		u32 d;
+
+		pbw0 = tunnel->ip6rd.prefixlen >> 5;
+		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
+
+		d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
+		    tunnel->ip6rd.relay_prefixlen;
+
+		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
+		if (pbi1 > 0)
+			d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
+			     (32 - pbi1);
+
+		dst = tunnel->ip6rd.relay_prefix | htonl(d);
+	}
+#else
+	if (v6dst->s6_addr16[0] == htons(0x2002)) {
+		/* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
+		memcpy(&dst, &v6dst->s6_addr16[1], 4);
+	}
+#endif
+	return dst;
+}
+
+/*
+ *	This function assumes it is being called from dev_queue_xmit()
+ *	and that skb is filled properly by that function.
+ */
+
+static netdev_tx_t ipip6_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;
+	const struct ipv6hdr *iph6 = ipv6_hdr(skb);
+	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 */
+	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;
+	const struct in6_addr *addr6;
+	int addr_type;
+
+	if (skb->protocol != htons(ETH_P_IPV6))
+		goto tx_error;
+
+	if (tos == 1)
+		tos = ipv6_get_dsfield(iph6);
+
+	/* ISATAP (RFC4214) - must come before 6to4 */
+	if (dev->priv_flags & IFF_ISATAP) {
+		struct neighbour *neigh = NULL;
+		bool do_tx_error = false;
+
+		if (skb_dst(skb))
+			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
+
+		if (neigh == NULL) {
+			if (net_ratelimit())
+				printk(KERN_DEBUG "sit: nexthop == NULL\n");
+			goto tx_error;
+		}
+
+		addr6 = (const struct in6_addr*)&neigh->primary_key;
+		addr_type = ipv6_addr_type(addr6);
+
+		if ((addr_type & IPV6_ADDR_UNICAST) &&
+		     ipv6_addr_is_isatap(addr6))
+			dst = addr6->s6_addr32[3];
+		else
+			do_tx_error = true;
+
+		neigh_release(neigh);
+		if (do_tx_error)
+			goto tx_error;
+	}
+
+	if (!dst)
+		dst = try_6rd(&iph6->daddr, tunnel);
+
+	if (!dst) {
+		struct neighbour *neigh = NULL;
+		bool do_tx_error = false;
+
+		if (skb_dst(skb))
+			neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
+
+		if (neigh == NULL) {
+			if (net_ratelimit())
+				printk(KERN_DEBUG "sit: nexthop == NULL\n");
+			goto tx_error;
+		}
+
+		addr6 = (const struct in6_addr*)&neigh->primary_key;
+		addr_type = ipv6_addr_type(addr6);
+
+		if (addr_type == IPV6_ADDR_ANY) {
+			addr6 = &ipv6_hdr(skb)->daddr;
+			addr_type = ipv6_addr_type(addr6);
+		}
+
+		if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
+			dst = addr6->s6_addr32[3];
+		else
+			do_tx_error = true;
+
+		neigh_release(neigh);
+		if (do_tx_error)
+			goto tx_error;
+	}
+
+	rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
+				   dst, tiph->saddr,
+				   0, 0,
+				   IPPROTO_IPV6, RT_TOS(tos),
+				   tunnel->parms.link);
+	if (IS_ERR(rt)) {
+		dev->stats.tx_carrier_errors++;
+		goto tx_error_icmp;
+	}
+	if (rt->rt_type != RTN_UNICAST) {
+		ip_rt_put(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;
+	}
+
+	if (df) {
+		mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
+
+		if (mtu < 68) {
+			dev->stats.collisions++;
+			ip_rt_put(rt);
+			goto tx_error;
+		}
+
+		if (mtu < IPV6_MIN_MTU) {
+			mtu = IPV6_MIN_MTU;
+			df = 0;
+		}
+
+		if (tunnel->parms.iph.daddr && skb_dst(skb))
+			skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
+
+		if (skb->len > mtu) {
+			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, 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;
+		iph6 = ipv6_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 = 0;
+	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_IPV6;
+	iph->tos		=	INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
+	iph->daddr		=	fl4.daddr;
+	iph->saddr		=	fl4.saddr;
+
+	if ((iph->ttl = tiph->ttl) == 0)
+		iph->ttl	=	iph6->hop_limit;
+
+	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 ipip6_tunnel_bind_dev(struct net_device *dev)
+{
+	struct net_device *tdev = NULL;
+	struct ip_tunnel *tunnel;
+	const struct iphdr *iph;
+	struct flowi4 fl4;
+
+	tunnel = netdev_priv(dev);
+	iph = &tunnel->parms.iph;
+
+	if (iph->daddr) {
+		struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
+							  iph->daddr, iph->saddr,
+							  0, 0,
+							  IPPROTO_IPV6,
+							  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);
+		if (dev->mtu < IPV6_MIN_MTU)
+			dev->mtu = IPV6_MIN_MTU;
+	}
+	dev->iflink = tunnel->parms.link;
+}
+
+static int
+ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	int err = 0;
+	struct ip_tunnel_parm p;
+	struct ip_tunnel_prl prl;
+	struct ip_tunnel *t;
+	struct net *net = dev_net(dev);
+	struct sit_net *sitn = net_generic(net, sit_net_id);
+#ifdef CONFIG_IPV6_SIT_6RD
+	struct ip_tunnel_6rd ip6rd;
+#endif
+
+	switch (cmd) {
+	case SIOCGETTUNNEL:
+#ifdef CONFIG_IPV6_SIT_6RD
+	case SIOCGET6RD:
+#endif
+		t = NULL;
+		if (dev == sitn->fb_tunnel_dev) {
+			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
+				err = -EFAULT;
+				break;
+			}
+			t = ipip6_tunnel_locate(net, &p, 0);
+		}
+		if (t == NULL)
+			t = netdev_priv(dev);
+
+		err = -EFAULT;
+		if (cmd == SIOCGETTUNNEL) {
+			memcpy(&p, &t->parms, sizeof(p));
+			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
+					 sizeof(p)))
+				goto done;
+#ifdef CONFIG_IPV6_SIT_6RD
+		} else {
+			ip6rd.prefix = t->ip6rd.prefix;
+			ip6rd.relay_prefix = t->ip6rd.relay_prefix;
+			ip6rd.prefixlen = t->ip6rd.prefixlen;
+			ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
+			if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
+					 sizeof(ip6rd)))
+				goto done;
+#endif
+		}
+		err = 0;
+		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_IPV6 ||
+		    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 = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
+
+		if (dev != sitn->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);
+				ipip6_tunnel_unlink(sitn, 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);
+				ipip6_tunnel_link(sitn, 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;
+				if (t->parms.link != p.link) {
+					t->parms.link = p.link;
+					ipip6_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 == sitn->fb_tunnel_dev) {
+			err = -EFAULT;
+			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
+				goto done;
+			err = -ENOENT;
+			if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
+				goto done;
+			err = -EPERM;
+			if (t == netdev_priv(sitn->fb_tunnel_dev))
+				goto done;
+			dev = t->dev;
+		}
+		unregister_netdevice(dev);
+		err = 0;
+		break;
+
+	case SIOCGETPRL:
+		err = -EINVAL;
+		if (dev == sitn->fb_tunnel_dev)
+			goto done;
+		err = -ENOENT;
+		if (!(t = netdev_priv(dev)))
+			goto done;
+		err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
+		break;
+
+	case SIOCADDPRL:
+	case SIOCDELPRL:
+	case SIOCCHGPRL:
+		err = -EPERM;
+		if (!capable(CAP_NET_ADMIN))
+			goto done;
+		err = -EINVAL;
+		if (dev == sitn->fb_tunnel_dev)
+			goto done;
+		err = -EFAULT;
+		if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
+			goto done;
+		err = -ENOENT;
+		if (!(t = netdev_priv(dev)))
+			goto done;
+
+		switch (cmd) {
+		case SIOCDELPRL:
+			err = ipip6_tunnel_del_prl(t, &prl);
+			break;
+		case SIOCADDPRL:
+		case SIOCCHGPRL:
+			err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
+			break;
+		}
+		netdev_state_change(dev);
+		break;
+
+#ifdef CONFIG_IPV6_SIT_6RD
+	case SIOCADD6RD:
+	case SIOCCHG6RD:
+	case SIOCDEL6RD:
+		err = -EPERM;
+		if (!capable(CAP_NET_ADMIN))
+			goto done;
+
+		err = -EFAULT;
+		if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
+				   sizeof(ip6rd)))
+			goto done;
+
+		t = netdev_priv(dev);
+
+		if (cmd != SIOCDEL6RD) {
+			struct in6_addr prefix;
+			__be32 relay_prefix;
+
+			err = -EINVAL;
+			if (ip6rd.relay_prefixlen > 32 ||
+			    ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
+				goto done;
+
+			ipv6_addr_prefix(&prefix, &ip6rd.prefix,
+					 ip6rd.prefixlen);
+			if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
+				goto done;
+			if (ip6rd.relay_prefixlen)
+				relay_prefix = ip6rd.relay_prefix &
+					       htonl(0xffffffffUL <<
+						     (32 - ip6rd.relay_prefixlen));
+			else
+				relay_prefix = 0;
+			if (relay_prefix != ip6rd.relay_prefix)
+				goto done;
+
+			t->ip6rd.prefix = prefix;
+			t->ip6rd.relay_prefix = relay_prefix;
+			t->ip6rd.prefixlen = ip6rd.prefixlen;
+			t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
+		} else
+			ipip6_tunnel_clone_6rd(dev, sitn);
+
+		err = 0;
+		break;
+#endif
+
+	default:
+		err = -EINVAL;
+	}
+
+done:
+	return err;
+}
+
+static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
+		return -EINVAL;
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops ipip6_netdev_ops = {
+	.ndo_uninit	= ipip6_tunnel_uninit,
+	.ndo_start_xmit	= ipip6_tunnel_xmit,
+	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
+	.ndo_change_mtu	= ipip6_tunnel_change_mtu,
+	.ndo_get_stats	= ipip6_get_stats,
+};
+
+static void ipip6_dev_free(struct net_device *dev)
+{
+	free_percpu(dev->tstats);
+	free_netdev(dev);
+}
+
+static void ipip6_tunnel_setup(struct net_device *dev)
+{
+	dev->netdev_ops		= &ipip6_netdev_ops;
+	dev->destructor 	= ipip6_dev_free;
+
+	dev->type		= ARPHRD_SIT;
+	dev->hard_header_len 	= LL_MAX_HEADER + sizeof(struct iphdr);
+	dev->mtu		= ETH_DATA_LEN - sizeof(struct iphdr);
+	dev->flags		= IFF_NOARP;
+	dev->priv_flags	       &= ~IFF_XMIT_DST_RELEASE;
+	dev->iflink		= 0;
+	dev->addr_len		= 4;
+	dev->features		|= NETIF_F_NETNS_LOCAL;
+	dev->features		|= NETIF_F_LLTX;
+}
+
+static int ipip6_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);
+
+	ipip6_tunnel_bind_dev(dev);
+	dev->tstats = alloc_percpu(struct pcpu_tstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct iphdr *iph = &tunnel->parms.iph;
+	struct net *net = dev_net(dev);
+	struct sit_net *sitn = net_generic(net, sit_net_id);
+
+	tunnel->dev = dev;
+	strcpy(tunnel->parms.name, dev->name);
+
+	iph->version		= 4;
+	iph->protocol		= IPPROTO_IPV6;
+	iph->ihl		= 5;
+	iph->ttl		= 64;
+
+	dev->tstats = alloc_percpu(struct pcpu_tstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+	dev_hold(dev);
+	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
+	return 0;
+}
+
+static struct xfrm_tunnel sit_handler __read_mostly = {
+	.handler	=	ipip6_rcv,
+	.err_handler	=	ipip6_err,
+	.priority	=	1,
+};
+
+static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, 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(sitn->tunnels[prio][h]);
+			while (t != NULL) {
+				unregister_netdevice_queue(t->dev, head);
+				t = rtnl_dereference(t->next);
+			}
+		}
+	}
+}
+
+static int __net_init sit_init_net(struct net *net)
+{
+	struct sit_net *sitn = net_generic(net, sit_net_id);
+	struct ip_tunnel *t;
+	int err;
+
+	sitn->tunnels[0] = sitn->tunnels_wc;
+	sitn->tunnels[1] = sitn->tunnels_l;
+	sitn->tunnels[2] = sitn->tunnels_r;
+	sitn->tunnels[3] = sitn->tunnels_r_l;
+
+	sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
+					   ipip6_tunnel_setup);
+	if (!sitn->fb_tunnel_dev) {
+		err = -ENOMEM;
+		goto err_alloc_dev;
+	}
+	dev_net_set(sitn->fb_tunnel_dev, net);
+
+	err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
+	if (err)
+		goto err_dev_free;
+
+	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
+
+	if ((err = register_netdev(sitn->fb_tunnel_dev)))
+		goto err_reg_dev;
+
+	t = netdev_priv(sitn->fb_tunnel_dev);
+
+	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
+	return 0;
+
+err_reg_dev:
+	dev_put(sitn->fb_tunnel_dev);
+err_dev_free:
+	ipip6_dev_free(sitn->fb_tunnel_dev);
+err_alloc_dev:
+	return err;
+}
+
+static void __net_exit sit_exit_net(struct net *net)
+{
+	struct sit_net *sitn = net_generic(net, sit_net_id);
+	LIST_HEAD(list);
+
+	rtnl_lock();
+	sit_destroy_tunnels(sitn, &list);
+	unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
+	unregister_netdevice_many(&list);
+	rtnl_unlock();
+}
+
+static struct pernet_operations sit_net_ops = {
+	.init = sit_init_net,
+	.exit = sit_exit_net,
+	.id   = &sit_net_id,
+	.size = sizeof(struct sit_net),
+};
+
+static void __exit sit_cleanup(void)
+{
+	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
+
+	unregister_pernet_device(&sit_net_ops);
+	rcu_barrier(); /* Wait for completion of call_rcu()'s */
+}
+
+static int __init sit_init(void)
+{
+	int err;
+
+	printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
+
+	err = register_pernet_device(&sit_net_ops);
+	if (err < 0)
+		return err;
+	err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
+	if (err < 0) {
+		unregister_pernet_device(&sit_net_ops);
+		printk(KERN_INFO "sit init: Can't add protocol\n");
+	}
+	return err;
+}
+
+module_init(sit_init);
+module_exit(sit_cleanup);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETDEV("sit0");