xref: /linux/net/ipv6/ip6_tunnel.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
1 /*
2  *	IPv6 tunneling device
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Ville Nuorvala		<vnuorval@tcs.hut.fi>
7  *	Yasuyuki Kozakai	<kozakai@linux-ipv6.org>
8  *
9  *      Based on:
10  *      linux/net/ipv6/sit.c and linux/net/ipv4/ipip.c
11  *
12  *      RFC 2473
13  *
14  *	This program is free software; you can redistribute it and/or
15  *      modify it under the terms of the GNU General Public License
16  *      as published by the Free Software Foundation; either version
17  *      2 of the License, or (at your option) any later version.
18  *
19  */
20 
21 #include <linux/module.h>
22 #include <linux/capability.h>
23 #include <linux/errno.h>
24 #include <linux/types.h>
25 #include <linux/sockios.h>
26 #include <linux/icmp.h>
27 #include <linux/if.h>
28 #include <linux/in.h>
29 #include <linux/ip.h>
30 #include <linux/if_tunnel.h>
31 #include <linux/net.h>
32 #include <linux/in6.h>
33 #include <linux/netdevice.h>
34 #include <linux/if_arp.h>
35 #include <linux/icmpv6.h>
36 #include <linux/init.h>
37 #include <linux/route.h>
38 #include <linux/rtnetlink.h>
39 #include <linux/netfilter_ipv6.h>
40 #include <linux/slab.h>
41 
42 #include <asm/uaccess.h>
43 #include <asm/atomic.h>
44 
45 #include <net/icmp.h>
46 #include <net/ip.h>
47 #include <net/ipv6.h>
48 #include <net/ip6_route.h>
49 #include <net/addrconf.h>
50 #include <net/ip6_tunnel.h>
51 #include <net/xfrm.h>
52 #include <net/dsfield.h>
53 #include <net/inet_ecn.h>
54 #include <net/net_namespace.h>
55 #include <net/netns/generic.h>
56 
57 MODULE_AUTHOR("Ville Nuorvala");
58 MODULE_DESCRIPTION("IPv6 tunneling device");
59 MODULE_LICENSE("GPL");
60 
61 #define IPV6_TLV_TEL_DST_SIZE 8
62 
63 #ifdef IP6_TNL_DEBUG
64 #define IP6_TNL_TRACE(x...) printk(KERN_DEBUG "%s:" x "\n", __func__)
65 #else
66 #define IP6_TNL_TRACE(x...) do {;} while(0)
67 #endif
68 
69 #define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)
70 #define IPV6_TCLASS_SHIFT 20
71 
72 #define HASH_SIZE  32
73 
74 #define HASH(addr) ((__force u32)((addr)->s6_addr32[0] ^ (addr)->s6_addr32[1] ^ \
75 		     (addr)->s6_addr32[2] ^ (addr)->s6_addr32[3]) & \
76 		    (HASH_SIZE - 1))
77 
78 static void ip6_tnl_dev_init(struct net_device *dev);
79 static void ip6_tnl_dev_setup(struct net_device *dev);
80 
81 static int ip6_tnl_net_id __read_mostly;
82 struct ip6_tnl_net {
83 	/* the IPv6 tunnel fallback device */
84 	struct net_device *fb_tnl_dev;
85 	/* lists for storing tunnels in use */
86 	struct ip6_tnl *tnls_r_l[HASH_SIZE];
87 	struct ip6_tnl *tnls_wc[1];
88 	struct ip6_tnl **tnls[2];
89 };
90 
91 /*
92  * Locking : hash tables are protected by RCU and a spinlock
93  */
94 static DEFINE_SPINLOCK(ip6_tnl_lock);
95 
96 static inline struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
97 {
98 	struct dst_entry *dst = t->dst_cache;
99 
100 	if (dst && dst->obsolete &&
101 	    dst->ops->check(dst, t->dst_cookie) == NULL) {
102 		t->dst_cache = NULL;
103 		dst_release(dst);
104 		return NULL;
105 	}
106 
107 	return dst;
108 }
109 
110 static inline void ip6_tnl_dst_reset(struct ip6_tnl *t)
111 {
112 	dst_release(t->dst_cache);
113 	t->dst_cache = NULL;
114 }
115 
116 static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
117 {
118 	struct rt6_info *rt = (struct rt6_info *) dst;
119 	t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
120 	dst_release(t->dst_cache);
121 	t->dst_cache = dst;
122 }
123 
124 /**
125  * ip6_tnl_lookup - fetch tunnel matching the end-point addresses
126  *   @remote: the address of the tunnel exit-point
127  *   @local: the address of the tunnel entry-point
128  *
129  * Return:
130  *   tunnel matching given end-points if found,
131  *   else fallback tunnel if its device is up,
132  *   else %NULL
133  **/
134 
135 #define for_each_ip6_tunnel_rcu(start) \
136 	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
137 
138 static struct ip6_tnl *
139 ip6_tnl_lookup(struct net *net, struct in6_addr *remote, struct in6_addr *local)
140 {
141 	unsigned h0 = HASH(remote);
142 	unsigned h1 = HASH(local);
143 	struct ip6_tnl *t;
144 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
145 
146 	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[h0 ^ h1]) {
147 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
148 		    ipv6_addr_equal(remote, &t->parms.raddr) &&
149 		    (t->dev->flags & IFF_UP))
150 			return t;
151 	}
152 	t = rcu_dereference(ip6n->tnls_wc[0]);
153 	if (t && (t->dev->flags & IFF_UP))
154 		return t;
155 
156 	return NULL;
157 }
158 
159 /**
160  * ip6_tnl_bucket - get head of list matching given tunnel parameters
161  *   @p: parameters containing tunnel end-points
162  *
163  * Description:
164  *   ip6_tnl_bucket() returns the head of the list matching the
165  *   &struct in6_addr entries laddr and raddr in @p.
166  *
167  * Return: head of IPv6 tunnel list
168  **/
169 
170 static struct ip6_tnl **
171 ip6_tnl_bucket(struct ip6_tnl_net *ip6n, struct ip6_tnl_parm *p)
172 {
173 	struct in6_addr *remote = &p->raddr;
174 	struct in6_addr *local = &p->laddr;
175 	unsigned h = 0;
176 	int prio = 0;
177 
178 	if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
179 		prio = 1;
180 		h = HASH(remote) ^ HASH(local);
181 	}
182 	return &ip6n->tnls[prio][h];
183 }
184 
185 /**
186  * ip6_tnl_link - add tunnel to hash table
187  *   @t: tunnel to be added
188  **/
189 
190 static void
191 ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
192 {
193 	struct ip6_tnl **tp = ip6_tnl_bucket(ip6n, &t->parms);
194 
195 	spin_lock_bh(&ip6_tnl_lock);
196 	t->next = *tp;
197 	rcu_assign_pointer(*tp, t);
198 	spin_unlock_bh(&ip6_tnl_lock);
199 }
200 
201 /**
202  * ip6_tnl_unlink - remove tunnel from hash table
203  *   @t: tunnel to be removed
204  **/
205 
206 static void
207 ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
208 {
209 	struct ip6_tnl **tp;
210 
211 	for (tp = ip6_tnl_bucket(ip6n, &t->parms); *tp; tp = &(*tp)->next) {
212 		if (t == *tp) {
213 			spin_lock_bh(&ip6_tnl_lock);
214 			*tp = t->next;
215 			spin_unlock_bh(&ip6_tnl_lock);
216 			break;
217 		}
218 	}
219 }
220 
221 /**
222  * ip6_tnl_create() - create a new tunnel
223  *   @p: tunnel parameters
224  *   @pt: pointer to new tunnel
225  *
226  * Description:
227  *   Create tunnel matching given parameters.
228  *
229  * Return:
230  *   created tunnel or NULL
231  **/
232 
233 static struct ip6_tnl *ip6_tnl_create(struct net *net, struct ip6_tnl_parm *p)
234 {
235 	struct net_device *dev;
236 	struct ip6_tnl *t;
237 	char name[IFNAMSIZ];
238 	int err;
239 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
240 
241 	if (p->name[0])
242 		strlcpy(name, p->name, IFNAMSIZ);
243 	else
244 		sprintf(name, "ip6tnl%%d");
245 
246 	dev = alloc_netdev(sizeof (*t), name, ip6_tnl_dev_setup);
247 	if (dev == NULL)
248 		goto failed;
249 
250 	dev_net_set(dev, net);
251 
252 	if (strchr(name, '%')) {
253 		if (dev_alloc_name(dev, name) < 0)
254 			goto failed_free;
255 	}
256 
257 	t = netdev_priv(dev);
258 	t->parms = *p;
259 	ip6_tnl_dev_init(dev);
260 
261 	if ((err = register_netdevice(dev)) < 0)
262 		goto failed_free;
263 
264 	dev_hold(dev);
265 	ip6_tnl_link(ip6n, t);
266 	return t;
267 
268 failed_free:
269 	free_netdev(dev);
270 failed:
271 	return NULL;
272 }
273 
274 /**
275  * ip6_tnl_locate - find or create tunnel matching given parameters
276  *   @p: tunnel parameters
277  *   @create: != 0 if allowed to create new tunnel if no match found
278  *
279  * Description:
280  *   ip6_tnl_locate() first tries to locate an existing tunnel
281  *   based on @parms. If this is unsuccessful, but @create is set a new
282  *   tunnel device is created and registered for use.
283  *
284  * Return:
285  *   matching tunnel or NULL
286  **/
287 
288 static struct ip6_tnl *ip6_tnl_locate(struct net *net,
289 		struct ip6_tnl_parm *p, int create)
290 {
291 	struct in6_addr *remote = &p->raddr;
292 	struct in6_addr *local = &p->laddr;
293 	struct ip6_tnl *t;
294 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
295 
296 	for (t = *ip6_tnl_bucket(ip6n, p); t; t = t->next) {
297 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
298 		    ipv6_addr_equal(remote, &t->parms.raddr))
299 			return t;
300 	}
301 	if (!create)
302 		return NULL;
303 	return ip6_tnl_create(net, p);
304 }
305 
306 /**
307  * ip6_tnl_dev_uninit - tunnel device uninitializer
308  *   @dev: the device to be destroyed
309  *
310  * Description:
311  *   ip6_tnl_dev_uninit() removes tunnel from its list
312  **/
313 
314 static void
315 ip6_tnl_dev_uninit(struct net_device *dev)
316 {
317 	struct ip6_tnl *t = netdev_priv(dev);
318 	struct net *net = dev_net(dev);
319 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
320 
321 	if (dev == ip6n->fb_tnl_dev) {
322 		spin_lock_bh(&ip6_tnl_lock);
323 		ip6n->tnls_wc[0] = NULL;
324 		spin_unlock_bh(&ip6_tnl_lock);
325 	} else {
326 		ip6_tnl_unlink(ip6n, t);
327 	}
328 	ip6_tnl_dst_reset(t);
329 	dev_put(dev);
330 }
331 
332 /**
333  * parse_tvl_tnl_enc_lim - handle encapsulation limit option
334  *   @skb: received socket buffer
335  *
336  * Return:
337  *   0 if none was found,
338  *   else index to encapsulation limit
339  **/
340 
341 static __u16
342 parse_tlv_tnl_enc_lim(struct sk_buff *skb, __u8 * raw)
343 {
344 	struct ipv6hdr *ipv6h = (struct ipv6hdr *) raw;
345 	__u8 nexthdr = ipv6h->nexthdr;
346 	__u16 off = sizeof (*ipv6h);
347 
348 	while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
349 		__u16 optlen = 0;
350 		struct ipv6_opt_hdr *hdr;
351 		if (raw + off + sizeof (*hdr) > skb->data &&
352 		    !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
353 			break;
354 
355 		hdr = (struct ipv6_opt_hdr *) (raw + off);
356 		if (nexthdr == NEXTHDR_FRAGMENT) {
357 			struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
358 			if (frag_hdr->frag_off)
359 				break;
360 			optlen = 8;
361 		} else if (nexthdr == NEXTHDR_AUTH) {
362 			optlen = (hdr->hdrlen + 2) << 2;
363 		} else {
364 			optlen = ipv6_optlen(hdr);
365 		}
366 		if (nexthdr == NEXTHDR_DEST) {
367 			__u16 i = off + 2;
368 			while (1) {
369 				struct ipv6_tlv_tnl_enc_lim *tel;
370 
371 				/* No more room for encapsulation limit */
372 				if (i + sizeof (*tel) > off + optlen)
373 					break;
374 
375 				tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
376 				/* return index of option if found and valid */
377 				if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
378 				    tel->length == 1)
379 					return i;
380 				/* else jump to next option */
381 				if (tel->type)
382 					i += tel->length + 2;
383 				else
384 					i++;
385 			}
386 		}
387 		nexthdr = hdr->nexthdr;
388 		off += optlen;
389 	}
390 	return 0;
391 }
392 
393 /**
394  * ip6_tnl_err - tunnel error handler
395  *
396  * Description:
397  *   ip6_tnl_err() should handle errors in the tunnel according
398  *   to the specifications in RFC 2473.
399  **/
400 
401 static int
402 ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
403 	    u8 *type, u8 *code, int *msg, __u32 *info, int offset)
404 {
405 	struct ipv6hdr *ipv6h = (struct ipv6hdr *) skb->data;
406 	struct ip6_tnl *t;
407 	int rel_msg = 0;
408 	u8 rel_type = ICMPV6_DEST_UNREACH;
409 	u8 rel_code = ICMPV6_ADDR_UNREACH;
410 	__u32 rel_info = 0;
411 	__u16 len;
412 	int err = -ENOENT;
413 
414 	/* If the packet doesn't contain the original IPv6 header we are
415 	   in trouble since we might need the source address for further
416 	   processing of the error. */
417 
418 	rcu_read_lock();
419 	if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr,
420 					&ipv6h->saddr)) == NULL)
421 		goto out;
422 
423 	if (t->parms.proto != ipproto && t->parms.proto != 0)
424 		goto out;
425 
426 	err = 0;
427 
428 	switch (*type) {
429 		__u32 teli;
430 		struct ipv6_tlv_tnl_enc_lim *tel;
431 		__u32 mtu;
432 	case ICMPV6_DEST_UNREACH:
433 		if (net_ratelimit())
434 			printk(KERN_WARNING
435 			       "%s: Path to destination invalid "
436 			       "or inactive!\n", t->parms.name);
437 		rel_msg = 1;
438 		break;
439 	case ICMPV6_TIME_EXCEED:
440 		if ((*code) == ICMPV6_EXC_HOPLIMIT) {
441 			if (net_ratelimit())
442 				printk(KERN_WARNING
443 				       "%s: Too small hop limit or "
444 				       "routing loop in tunnel!\n",
445 				       t->parms.name);
446 			rel_msg = 1;
447 		}
448 		break;
449 	case ICMPV6_PARAMPROB:
450 		teli = 0;
451 		if ((*code) == ICMPV6_HDR_FIELD)
452 			teli = parse_tlv_tnl_enc_lim(skb, skb->data);
453 
454 		if (teli && teli == *info - 2) {
455 			tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
456 			if (tel->encap_limit == 0) {
457 				if (net_ratelimit())
458 					printk(KERN_WARNING
459 					       "%s: Too small encapsulation "
460 					       "limit or routing loop in "
461 					       "tunnel!\n", t->parms.name);
462 				rel_msg = 1;
463 			}
464 		} else if (net_ratelimit()) {
465 			printk(KERN_WARNING
466 			       "%s: Recipient unable to parse tunneled "
467 			       "packet!\n ", t->parms.name);
468 		}
469 		break;
470 	case ICMPV6_PKT_TOOBIG:
471 		mtu = *info - offset;
472 		if (mtu < IPV6_MIN_MTU)
473 			mtu = IPV6_MIN_MTU;
474 		t->dev->mtu = mtu;
475 
476 		if ((len = sizeof (*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) {
477 			rel_type = ICMPV6_PKT_TOOBIG;
478 			rel_code = 0;
479 			rel_info = mtu;
480 			rel_msg = 1;
481 		}
482 		break;
483 	}
484 
485 	*type = rel_type;
486 	*code = rel_code;
487 	*info = rel_info;
488 	*msg = rel_msg;
489 
490 out:
491 	rcu_read_unlock();
492 	return err;
493 }
494 
495 static int
496 ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
497 	   u8 type, u8 code, int offset, __be32 info)
498 {
499 	int rel_msg = 0;
500 	u8 rel_type = type;
501 	u8 rel_code = code;
502 	__u32 rel_info = ntohl(info);
503 	int err;
504 	struct sk_buff *skb2;
505 	struct iphdr *eiph;
506 	struct flowi fl;
507 	struct rtable *rt;
508 
509 	err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
510 			  &rel_msg, &rel_info, offset);
511 	if (err < 0)
512 		return err;
513 
514 	if (rel_msg == 0)
515 		return 0;
516 
517 	switch (rel_type) {
518 	case ICMPV6_DEST_UNREACH:
519 		if (rel_code != ICMPV6_ADDR_UNREACH)
520 			return 0;
521 		rel_type = ICMP_DEST_UNREACH;
522 		rel_code = ICMP_HOST_UNREACH;
523 		break;
524 	case ICMPV6_PKT_TOOBIG:
525 		if (rel_code != 0)
526 			return 0;
527 		rel_type = ICMP_DEST_UNREACH;
528 		rel_code = ICMP_FRAG_NEEDED;
529 		break;
530 	default:
531 		return 0;
532 	}
533 
534 	if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
535 		return 0;
536 
537 	skb2 = skb_clone(skb, GFP_ATOMIC);
538 	if (!skb2)
539 		return 0;
540 
541 	skb_dst_drop(skb2);
542 
543 	skb_pull(skb2, offset);
544 	skb_reset_network_header(skb2);
545 	eiph = ip_hdr(skb2);
546 
547 	/* Try to guess incoming interface */
548 	memset(&fl, 0, sizeof(fl));
549 	fl.fl4_dst = eiph->saddr;
550 	fl.fl4_tos = RT_TOS(eiph->tos);
551 	fl.proto = IPPROTO_IPIP;
552 	if (ip_route_output_key(dev_net(skb->dev), &rt, &fl))
553 		goto out;
554 
555 	skb2->dev = rt->dst.dev;
556 
557 	/* route "incoming" packet */
558 	if (rt->rt_flags & RTCF_LOCAL) {
559 		ip_rt_put(rt);
560 		rt = NULL;
561 		fl.fl4_dst = eiph->daddr;
562 		fl.fl4_src = eiph->saddr;
563 		fl.fl4_tos = eiph->tos;
564 		if (ip_route_output_key(dev_net(skb->dev), &rt, &fl) ||
565 		    rt->dst.dev->type != ARPHRD_TUNNEL) {
566 			ip_rt_put(rt);
567 			goto out;
568 		}
569 		skb_dst_set(skb2, (struct dst_entry *)rt);
570 	} else {
571 		ip_rt_put(rt);
572 		if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
573 				   skb2->dev) ||
574 		    skb_dst(skb2)->dev->type != ARPHRD_TUNNEL)
575 			goto out;
576 	}
577 
578 	/* change mtu on this route */
579 	if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {
580 		if (rel_info > dst_mtu(skb_dst(skb2)))
581 			goto out;
582 
583 		skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), rel_info);
584 	}
585 
586 	icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
587 
588 out:
589 	kfree_skb(skb2);
590 	return 0;
591 }
592 
593 static int
594 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
595 	   u8 type, u8 code, int offset, __be32 info)
596 {
597 	int rel_msg = 0;
598 	u8 rel_type = type;
599 	u8 rel_code = code;
600 	__u32 rel_info = ntohl(info);
601 	int err;
602 
603 	err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
604 			  &rel_msg, &rel_info, offset);
605 	if (err < 0)
606 		return err;
607 
608 	if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) {
609 		struct rt6_info *rt;
610 		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
611 
612 		if (!skb2)
613 			return 0;
614 
615 		skb_dst_drop(skb2);
616 		skb_pull(skb2, offset);
617 		skb_reset_network_header(skb2);
618 
619 		/* Try to guess incoming interface */
620 		rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr,
621 				NULL, 0, 0);
622 
623 		if (rt && rt->rt6i_dev)
624 			skb2->dev = rt->rt6i_dev;
625 
626 		icmpv6_send(skb2, rel_type, rel_code, rel_info);
627 
628 		if (rt)
629 			dst_release(&rt->dst);
630 
631 		kfree_skb(skb2);
632 	}
633 
634 	return 0;
635 }
636 
637 static void ip4ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,
638 					struct ipv6hdr *ipv6h,
639 					struct sk_buff *skb)
640 {
641 	__u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;
642 
643 	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
644 		ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield);
645 
646 	if (INET_ECN_is_ce(dsfield))
647 		IP_ECN_set_ce(ip_hdr(skb));
648 }
649 
650 static void ip6ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,
651 					struct ipv6hdr *ipv6h,
652 					struct sk_buff *skb)
653 {
654 	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
655 		ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb));
656 
657 	if (INET_ECN_is_ce(ipv6_get_dsfield(ipv6h)))
658 		IP6_ECN_set_ce(ipv6_hdr(skb));
659 }
660 
661 /* called with rcu_read_lock() */
662 static inline int ip6_tnl_rcv_ctl(struct ip6_tnl *t)
663 {
664 	struct ip6_tnl_parm *p = &t->parms;
665 	int ret = 0;
666 	struct net *net = dev_net(t->dev);
667 
668 	if (p->flags & IP6_TNL_F_CAP_RCV) {
669 		struct net_device *ldev = NULL;
670 
671 		if (p->link)
672 			ldev = dev_get_by_index_rcu(net, p->link);
673 
674 		if ((ipv6_addr_is_multicast(&p->laddr) ||
675 		     likely(ipv6_chk_addr(net, &p->laddr, ldev, 0))) &&
676 		    likely(!ipv6_chk_addr(net, &p->raddr, NULL, 0)))
677 			ret = 1;
678 
679 	}
680 	return ret;
681 }
682 
683 /**
684  * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
685  *   @skb: received socket buffer
686  *   @protocol: ethernet protocol ID
687  *   @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
688  *
689  * Return: 0
690  **/
691 
692 static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
693 		       __u8 ipproto,
694 		       void (*dscp_ecn_decapsulate)(struct ip6_tnl *t,
695 						    struct ipv6hdr *ipv6h,
696 						    struct sk_buff *skb))
697 {
698 	struct ip6_tnl *t;
699 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
700 
701 	rcu_read_lock();
702 
703 	if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr,
704 					&ipv6h->daddr)) != NULL) {
705 		if (t->parms.proto != ipproto && t->parms.proto != 0) {
706 			rcu_read_unlock();
707 			goto discard;
708 		}
709 
710 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
711 			rcu_read_unlock();
712 			goto discard;
713 		}
714 
715 		if (!ip6_tnl_rcv_ctl(t)) {
716 			t->dev->stats.rx_dropped++;
717 			rcu_read_unlock();
718 			goto discard;
719 		}
720 		secpath_reset(skb);
721 		skb->mac_header = skb->network_header;
722 		skb_reset_network_header(skb);
723 		skb->protocol = htons(protocol);
724 		skb->pkt_type = PACKET_HOST;
725 		memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
726 
727 		skb_tunnel_rx(skb, t->dev);
728 
729 		dscp_ecn_decapsulate(t, ipv6h, skb);
730 		netif_rx(skb);
731 		rcu_read_unlock();
732 		return 0;
733 	}
734 	rcu_read_unlock();
735 	return 1;
736 
737 discard:
738 	kfree_skb(skb);
739 	return 0;
740 }
741 
742 static int ip4ip6_rcv(struct sk_buff *skb)
743 {
744 	return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
745 			   ip4ip6_dscp_ecn_decapsulate);
746 }
747 
748 static int ip6ip6_rcv(struct sk_buff *skb)
749 {
750 	return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
751 			   ip6ip6_dscp_ecn_decapsulate);
752 }
753 
754 struct ipv6_tel_txoption {
755 	struct ipv6_txoptions ops;
756 	__u8 dst_opt[8];
757 };
758 
759 static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
760 {
761 	memset(opt, 0, sizeof(struct ipv6_tel_txoption));
762 
763 	opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
764 	opt->dst_opt[3] = 1;
765 	opt->dst_opt[4] = encap_limit;
766 	opt->dst_opt[5] = IPV6_TLV_PADN;
767 	opt->dst_opt[6] = 1;
768 
769 	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
770 	opt->ops.opt_nflen = 8;
771 }
772 
773 /**
774  * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
775  *   @t: the outgoing tunnel device
776  *   @hdr: IPv6 header from the incoming packet
777  *
778  * Description:
779  *   Avoid trivial tunneling loop by checking that tunnel exit-point
780  *   doesn't match source of incoming packet.
781  *
782  * Return:
783  *   1 if conflict,
784  *   0 else
785  **/
786 
787 static inline int
788 ip6_tnl_addr_conflict(struct ip6_tnl *t, struct ipv6hdr *hdr)
789 {
790 	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
791 }
792 
793 static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
794 {
795 	struct ip6_tnl_parm *p = &t->parms;
796 	int ret = 0;
797 	struct net *net = dev_net(t->dev);
798 
799 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
800 		struct net_device *ldev = NULL;
801 
802 		rcu_read_lock();
803 		if (p->link)
804 			ldev = dev_get_by_index_rcu(net, p->link);
805 
806 		if (unlikely(!ipv6_chk_addr(net, &p->laddr, ldev, 0)))
807 			printk(KERN_WARNING
808 			       "%s xmit: Local address not yet configured!\n",
809 			       p->name);
810 		else if (!ipv6_addr_is_multicast(&p->raddr) &&
811 			 unlikely(ipv6_chk_addr(net, &p->raddr, NULL, 0)))
812 			printk(KERN_WARNING
813 			       "%s xmit: Routing loop! "
814 			       "Remote address found on this node!\n",
815 			       p->name);
816 		else
817 			ret = 1;
818 		rcu_read_unlock();
819 	}
820 	return ret;
821 }
822 /**
823  * ip6_tnl_xmit2 - encapsulate packet and send
824  *   @skb: the outgoing socket buffer
825  *   @dev: the outgoing tunnel device
826  *   @dsfield: dscp code for outer header
827  *   @fl: flow of tunneled packet
828  *   @encap_limit: encapsulation limit
829  *   @pmtu: Path MTU is stored if packet is too big
830  *
831  * Description:
832  *   Build new header and do some sanity checks on the packet before sending
833  *   it.
834  *
835  * Return:
836  *   0 on success
837  *   -1 fail
838  *   %-EMSGSIZE message too big. return mtu in this case.
839  **/
840 
841 static int ip6_tnl_xmit2(struct sk_buff *skb,
842 			 struct net_device *dev,
843 			 __u8 dsfield,
844 			 struct flowi *fl,
845 			 int encap_limit,
846 			 __u32 *pmtu)
847 {
848 	struct net *net = dev_net(dev);
849 	struct ip6_tnl *t = netdev_priv(dev);
850 	struct net_device_stats *stats = &t->dev->stats;
851 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
852 	struct ipv6_tel_txoption opt;
853 	struct dst_entry *dst;
854 	struct net_device *tdev;
855 	int mtu;
856 	unsigned int max_headroom = sizeof(struct ipv6hdr);
857 	u8 proto;
858 	int err = -1;
859 	int pkt_len;
860 
861 	if ((dst = ip6_tnl_dst_check(t)) != NULL)
862 		dst_hold(dst);
863 	else {
864 		dst = ip6_route_output(net, NULL, fl);
865 
866 		if (dst->error || xfrm_lookup(net, &dst, fl, NULL, 0) < 0)
867 			goto tx_err_link_failure;
868 	}
869 
870 	tdev = dst->dev;
871 
872 	if (tdev == dev) {
873 		stats->collisions++;
874 		if (net_ratelimit())
875 			printk(KERN_WARNING
876 			       "%s: Local routing loop detected!\n",
877 			       t->parms.name);
878 		goto tx_err_dst_release;
879 	}
880 	mtu = dst_mtu(dst) - sizeof (*ipv6h);
881 	if (encap_limit >= 0) {
882 		max_headroom += 8;
883 		mtu -= 8;
884 	}
885 	if (mtu < IPV6_MIN_MTU)
886 		mtu = IPV6_MIN_MTU;
887 	if (skb_dst(skb))
888 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
889 	if (skb->len > mtu) {
890 		*pmtu = mtu;
891 		err = -EMSGSIZE;
892 		goto tx_err_dst_release;
893 	}
894 
895 	/*
896 	 * Okay, now see if we can stuff it in the buffer as-is.
897 	 */
898 	max_headroom += LL_RESERVED_SPACE(tdev);
899 
900 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
901 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
902 		struct sk_buff *new_skb;
903 
904 		if (!(new_skb = skb_realloc_headroom(skb, max_headroom)))
905 			goto tx_err_dst_release;
906 
907 		if (skb->sk)
908 			skb_set_owner_w(new_skb, skb->sk);
909 		kfree_skb(skb);
910 		skb = new_skb;
911 	}
912 	skb_dst_drop(skb);
913 	skb_dst_set(skb, dst_clone(dst));
914 
915 	skb->transport_header = skb->network_header;
916 
917 	proto = fl->proto;
918 	if (encap_limit >= 0) {
919 		init_tel_txopt(&opt, encap_limit);
920 		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
921 	}
922 	skb_push(skb, sizeof(struct ipv6hdr));
923 	skb_reset_network_header(skb);
924 	ipv6h = ipv6_hdr(skb);
925 	*(__be32*)ipv6h = fl->fl6_flowlabel | htonl(0x60000000);
926 	dsfield = INET_ECN_encapsulate(0, dsfield);
927 	ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
928 	ipv6h->hop_limit = t->parms.hop_limit;
929 	ipv6h->nexthdr = proto;
930 	ipv6_addr_copy(&ipv6h->saddr, &fl->fl6_src);
931 	ipv6_addr_copy(&ipv6h->daddr, &fl->fl6_dst);
932 	nf_reset(skb);
933 	pkt_len = skb->len;
934 	err = ip6_local_out(skb);
935 
936 	if (net_xmit_eval(err) == 0) {
937 		stats->tx_bytes += pkt_len;
938 		stats->tx_packets++;
939 	} else {
940 		stats->tx_errors++;
941 		stats->tx_aborted_errors++;
942 	}
943 	ip6_tnl_dst_store(t, dst);
944 	return 0;
945 tx_err_link_failure:
946 	stats->tx_carrier_errors++;
947 	dst_link_failure(skb);
948 tx_err_dst_release:
949 	dst_release(dst);
950 	return err;
951 }
952 
953 static inline int
954 ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
955 {
956 	struct ip6_tnl *t = netdev_priv(dev);
957 	struct iphdr  *iph = ip_hdr(skb);
958 	int encap_limit = -1;
959 	struct flowi fl;
960 	__u8 dsfield;
961 	__u32 mtu;
962 	int err;
963 
964 	if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
965 	    !ip6_tnl_xmit_ctl(t))
966 		return -1;
967 
968 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
969 		encap_limit = t->parms.encap_limit;
970 
971 	memcpy(&fl, &t->fl, sizeof (fl));
972 	fl.proto = IPPROTO_IPIP;
973 
974 	dsfield = ipv4_get_dsfield(iph);
975 
976 	if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
977 		fl.fl6_flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
978 					  & IPV6_TCLASS_MASK;
979 
980 	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl, encap_limit, &mtu);
981 	if (err != 0) {
982 		/* XXX: send ICMP error even if DF is not set. */
983 		if (err == -EMSGSIZE)
984 			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
985 				  htonl(mtu));
986 		return -1;
987 	}
988 
989 	return 0;
990 }
991 
992 static inline int
993 ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
994 {
995 	struct ip6_tnl *t = netdev_priv(dev);
996 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
997 	int encap_limit = -1;
998 	__u16 offset;
999 	struct flowi fl;
1000 	__u8 dsfield;
1001 	__u32 mtu;
1002 	int err;
1003 
1004 	if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
1005 	    !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
1006 		return -1;
1007 
1008 	offset = parse_tlv_tnl_enc_lim(skb, skb_network_header(skb));
1009 	if (offset > 0) {
1010 		struct ipv6_tlv_tnl_enc_lim *tel;
1011 		tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
1012 		if (tel->encap_limit == 0) {
1013 			icmpv6_send(skb, ICMPV6_PARAMPROB,
1014 				    ICMPV6_HDR_FIELD, offset + 2);
1015 			return -1;
1016 		}
1017 		encap_limit = tel->encap_limit - 1;
1018 	} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1019 		encap_limit = t->parms.encap_limit;
1020 
1021 	memcpy(&fl, &t->fl, sizeof (fl));
1022 	fl.proto = IPPROTO_IPV6;
1023 
1024 	dsfield = ipv6_get_dsfield(ipv6h);
1025 	if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
1026 		fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
1027 	if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
1028 		fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
1029 
1030 	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl, encap_limit, &mtu);
1031 	if (err != 0) {
1032 		if (err == -EMSGSIZE)
1033 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1034 		return -1;
1035 	}
1036 
1037 	return 0;
1038 }
1039 
1040 static netdev_tx_t
1041 ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1042 {
1043 	struct ip6_tnl *t = netdev_priv(dev);
1044 	struct net_device_stats *stats = &t->dev->stats;
1045 	int ret;
1046 
1047 	switch (skb->protocol) {
1048 	case htons(ETH_P_IP):
1049 		ret = ip4ip6_tnl_xmit(skb, dev);
1050 		break;
1051 	case htons(ETH_P_IPV6):
1052 		ret = ip6ip6_tnl_xmit(skb, dev);
1053 		break;
1054 	default:
1055 		goto tx_err;
1056 	}
1057 
1058 	if (ret < 0)
1059 		goto tx_err;
1060 
1061 	return NETDEV_TX_OK;
1062 
1063 tx_err:
1064 	stats->tx_errors++;
1065 	stats->tx_dropped++;
1066 	kfree_skb(skb);
1067 	return NETDEV_TX_OK;
1068 }
1069 
1070 static void ip6_tnl_set_cap(struct ip6_tnl *t)
1071 {
1072 	struct ip6_tnl_parm *p = &t->parms;
1073 	int ltype = ipv6_addr_type(&p->laddr);
1074 	int rtype = ipv6_addr_type(&p->raddr);
1075 
1076 	p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV);
1077 
1078 	if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
1079 	    rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
1080 	    !((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
1081 	    (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
1082 		if (ltype&IPV6_ADDR_UNICAST)
1083 			p->flags |= IP6_TNL_F_CAP_XMIT;
1084 		if (rtype&IPV6_ADDR_UNICAST)
1085 			p->flags |= IP6_TNL_F_CAP_RCV;
1086 	}
1087 }
1088 
1089 static void ip6_tnl_link_config(struct ip6_tnl *t)
1090 {
1091 	struct net_device *dev = t->dev;
1092 	struct ip6_tnl_parm *p = &t->parms;
1093 	struct flowi *fl = &t->fl;
1094 
1095 	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
1096 	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
1097 
1098 	/* Set up flowi template */
1099 	ipv6_addr_copy(&fl->fl6_src, &p->laddr);
1100 	ipv6_addr_copy(&fl->fl6_dst, &p->raddr);
1101 	fl->oif = p->link;
1102 	fl->fl6_flowlabel = 0;
1103 
1104 	if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
1105 		fl->fl6_flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
1106 	if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
1107 		fl->fl6_flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
1108 
1109 	ip6_tnl_set_cap(t);
1110 
1111 	if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
1112 		dev->flags |= IFF_POINTOPOINT;
1113 	else
1114 		dev->flags &= ~IFF_POINTOPOINT;
1115 
1116 	dev->iflink = p->link;
1117 
1118 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
1119 		int strict = (ipv6_addr_type(&p->raddr) &
1120 			      (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
1121 
1122 		struct rt6_info *rt = rt6_lookup(dev_net(dev),
1123 						 &p->raddr, &p->laddr,
1124 						 p->link, strict);
1125 
1126 		if (rt == NULL)
1127 			return;
1128 
1129 		if (rt->rt6i_dev) {
1130 			dev->hard_header_len = rt->rt6i_dev->hard_header_len +
1131 				sizeof (struct ipv6hdr);
1132 
1133 			dev->mtu = rt->rt6i_dev->mtu - sizeof (struct ipv6hdr);
1134 
1135 			if (dev->mtu < IPV6_MIN_MTU)
1136 				dev->mtu = IPV6_MIN_MTU;
1137 		}
1138 		dst_release(&rt->dst);
1139 	}
1140 }
1141 
1142 /**
1143  * ip6_tnl_change - update the tunnel parameters
1144  *   @t: tunnel to be changed
1145  *   @p: tunnel configuration parameters
1146  *
1147  * Description:
1148  *   ip6_tnl_change() updates the tunnel parameters
1149  **/
1150 
1151 static int
1152 ip6_tnl_change(struct ip6_tnl *t, struct ip6_tnl_parm *p)
1153 {
1154 	ipv6_addr_copy(&t->parms.laddr, &p->laddr);
1155 	ipv6_addr_copy(&t->parms.raddr, &p->raddr);
1156 	t->parms.flags = p->flags;
1157 	t->parms.hop_limit = p->hop_limit;
1158 	t->parms.encap_limit = p->encap_limit;
1159 	t->parms.flowinfo = p->flowinfo;
1160 	t->parms.link = p->link;
1161 	t->parms.proto = p->proto;
1162 	ip6_tnl_dst_reset(t);
1163 	ip6_tnl_link_config(t);
1164 	return 0;
1165 }
1166 
1167 /**
1168  * ip6_tnl_ioctl - configure ipv6 tunnels from userspace
1169  *   @dev: virtual device associated with tunnel
1170  *   @ifr: parameters passed from userspace
1171  *   @cmd: command to be performed
1172  *
1173  * Description:
1174  *   ip6_tnl_ioctl() is used for managing IPv6 tunnels
1175  *   from userspace.
1176  *
1177  *   The possible commands are the following:
1178  *     %SIOCGETTUNNEL: get tunnel parameters for device
1179  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
1180  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
1181  *     %SIOCDELTUNNEL: delete tunnel
1182  *
1183  *   The fallback device "ip6tnl0", created during module
1184  *   initialization, can be used for creating other tunnel devices.
1185  *
1186  * Return:
1187  *   0 on success,
1188  *   %-EFAULT if unable to copy data to or from userspace,
1189  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
1190  *   %-EINVAL if passed tunnel parameters are invalid,
1191  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
1192  *   %-ENODEV if attempting to change or delete a nonexisting device
1193  **/
1194 
1195 static int
1196 ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1197 {
1198 	int err = 0;
1199 	struct ip6_tnl_parm p;
1200 	struct ip6_tnl *t = NULL;
1201 	struct net *net = dev_net(dev);
1202 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1203 
1204 	switch (cmd) {
1205 	case SIOCGETTUNNEL:
1206 		if (dev == ip6n->fb_tnl_dev) {
1207 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
1208 				err = -EFAULT;
1209 				break;
1210 			}
1211 			t = ip6_tnl_locate(net, &p, 0);
1212 		}
1213 		if (t == NULL)
1214 			t = netdev_priv(dev);
1215 		memcpy(&p, &t->parms, sizeof (p));
1216 		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof (p))) {
1217 			err = -EFAULT;
1218 		}
1219 		break;
1220 	case SIOCADDTUNNEL:
1221 	case SIOCCHGTUNNEL:
1222 		err = -EPERM;
1223 		if (!capable(CAP_NET_ADMIN))
1224 			break;
1225 		err = -EFAULT;
1226 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
1227 			break;
1228 		err = -EINVAL;
1229 		if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP &&
1230 		    p.proto != 0)
1231 			break;
1232 		t = ip6_tnl_locate(net, &p, cmd == SIOCADDTUNNEL);
1233 		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
1234 			if (t != NULL) {
1235 				if (t->dev != dev) {
1236 					err = -EEXIST;
1237 					break;
1238 				}
1239 			} else
1240 				t = netdev_priv(dev);
1241 
1242 			ip6_tnl_unlink(ip6n, t);
1243 			err = ip6_tnl_change(t, &p);
1244 			ip6_tnl_link(ip6n, t);
1245 			netdev_state_change(dev);
1246 		}
1247 		if (t) {
1248 			err = 0;
1249 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof (p)))
1250 				err = -EFAULT;
1251 
1252 		} else
1253 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1254 		break;
1255 	case SIOCDELTUNNEL:
1256 		err = -EPERM;
1257 		if (!capable(CAP_NET_ADMIN))
1258 			break;
1259 
1260 		if (dev == ip6n->fb_tnl_dev) {
1261 			err = -EFAULT;
1262 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
1263 				break;
1264 			err = -ENOENT;
1265 			if ((t = ip6_tnl_locate(net, &p, 0)) == NULL)
1266 				break;
1267 			err = -EPERM;
1268 			if (t->dev == ip6n->fb_tnl_dev)
1269 				break;
1270 			dev = t->dev;
1271 		}
1272 		err = 0;
1273 		unregister_netdevice(dev);
1274 		break;
1275 	default:
1276 		err = -EINVAL;
1277 	}
1278 	return err;
1279 }
1280 
1281 /**
1282  * ip6_tnl_change_mtu - change mtu manually for tunnel device
1283  *   @dev: virtual device associated with tunnel
1284  *   @new_mtu: the new mtu
1285  *
1286  * Return:
1287  *   0 on success,
1288  *   %-EINVAL if mtu too small
1289  **/
1290 
1291 static int
1292 ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
1293 {
1294 	if (new_mtu < IPV6_MIN_MTU) {
1295 		return -EINVAL;
1296 	}
1297 	dev->mtu = new_mtu;
1298 	return 0;
1299 }
1300 
1301 
1302 static const struct net_device_ops ip6_tnl_netdev_ops = {
1303 	.ndo_uninit = ip6_tnl_dev_uninit,
1304 	.ndo_start_xmit = ip6_tnl_xmit,
1305 	.ndo_do_ioctl = ip6_tnl_ioctl,
1306 	.ndo_change_mtu = ip6_tnl_change_mtu,
1307 };
1308 
1309 /**
1310  * ip6_tnl_dev_setup - setup virtual tunnel device
1311  *   @dev: virtual device associated with tunnel
1312  *
1313  * Description:
1314  *   Initialize function pointers and device parameters
1315  **/
1316 
1317 static void ip6_tnl_dev_setup(struct net_device *dev)
1318 {
1319 	dev->netdev_ops = &ip6_tnl_netdev_ops;
1320 	dev->destructor = free_netdev;
1321 
1322 	dev->type = ARPHRD_TUNNEL6;
1323 	dev->hard_header_len = LL_MAX_HEADER + sizeof (struct ipv6hdr);
1324 	dev->mtu = ETH_DATA_LEN - sizeof (struct ipv6hdr);
1325 	dev->flags |= IFF_NOARP;
1326 	dev->addr_len = sizeof(struct in6_addr);
1327 	dev->features |= NETIF_F_NETNS_LOCAL;
1328 }
1329 
1330 
1331 /**
1332  * ip6_tnl_dev_init_gen - general initializer for all tunnel devices
1333  *   @dev: virtual device associated with tunnel
1334  **/
1335 
1336 static inline void
1337 ip6_tnl_dev_init_gen(struct net_device *dev)
1338 {
1339 	struct ip6_tnl *t = netdev_priv(dev);
1340 	t->dev = dev;
1341 	strcpy(t->parms.name, dev->name);
1342 }
1343 
1344 /**
1345  * ip6_tnl_dev_init - initializer for all non fallback tunnel devices
1346  *   @dev: virtual device associated with tunnel
1347  **/
1348 
1349 static void ip6_tnl_dev_init(struct net_device *dev)
1350 {
1351 	struct ip6_tnl *t = netdev_priv(dev);
1352 	ip6_tnl_dev_init_gen(dev);
1353 	ip6_tnl_link_config(t);
1354 }
1355 
1356 /**
1357  * ip6_fb_tnl_dev_init - initializer for fallback tunnel device
1358  *   @dev: fallback device
1359  *
1360  * Return: 0
1361  **/
1362 
1363 static void __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
1364 {
1365 	struct ip6_tnl *t = netdev_priv(dev);
1366 	struct net *net = dev_net(dev);
1367 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1368 
1369 	ip6_tnl_dev_init_gen(dev);
1370 	t->parms.proto = IPPROTO_IPV6;
1371 	dev_hold(dev);
1372 	ip6n->tnls_wc[0] = t;
1373 }
1374 
1375 static struct xfrm6_tunnel ip4ip6_handler = {
1376 	.handler	= ip4ip6_rcv,
1377 	.err_handler	= ip4ip6_err,
1378 	.priority	=	1,
1379 };
1380 
1381 static struct xfrm6_tunnel ip6ip6_handler = {
1382 	.handler	= ip6ip6_rcv,
1383 	.err_handler	= ip6ip6_err,
1384 	.priority	=	1,
1385 };
1386 
1387 static void __net_exit ip6_tnl_destroy_tunnels(struct ip6_tnl_net *ip6n)
1388 {
1389 	int h;
1390 	struct ip6_tnl *t;
1391 	LIST_HEAD(list);
1392 
1393 	for (h = 0; h < HASH_SIZE; h++) {
1394 		t = ip6n->tnls_r_l[h];
1395 		while (t != NULL) {
1396 			unregister_netdevice_queue(t->dev, &list);
1397 			t = t->next;
1398 		}
1399 	}
1400 
1401 	t = ip6n->tnls_wc[0];
1402 	unregister_netdevice_queue(t->dev, &list);
1403 	unregister_netdevice_many(&list);
1404 }
1405 
1406 static int __net_init ip6_tnl_init_net(struct net *net)
1407 {
1408 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1409 	int err;
1410 
1411 	ip6n->tnls[0] = ip6n->tnls_wc;
1412 	ip6n->tnls[1] = ip6n->tnls_r_l;
1413 
1414 	err = -ENOMEM;
1415 	ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
1416 				      ip6_tnl_dev_setup);
1417 
1418 	if (!ip6n->fb_tnl_dev)
1419 		goto err_alloc_dev;
1420 	dev_net_set(ip6n->fb_tnl_dev, net);
1421 
1422 	ip6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
1423 
1424 	err = register_netdev(ip6n->fb_tnl_dev);
1425 	if (err < 0)
1426 		goto err_register;
1427 	return 0;
1428 
1429 err_register:
1430 	free_netdev(ip6n->fb_tnl_dev);
1431 err_alloc_dev:
1432 	return err;
1433 }
1434 
1435 static void __net_exit ip6_tnl_exit_net(struct net *net)
1436 {
1437 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1438 
1439 	rtnl_lock();
1440 	ip6_tnl_destroy_tunnels(ip6n);
1441 	rtnl_unlock();
1442 }
1443 
1444 static struct pernet_operations ip6_tnl_net_ops = {
1445 	.init = ip6_tnl_init_net,
1446 	.exit = ip6_tnl_exit_net,
1447 	.id   = &ip6_tnl_net_id,
1448 	.size = sizeof(struct ip6_tnl_net),
1449 };
1450 
1451 /**
1452  * ip6_tunnel_init - register protocol and reserve needed resources
1453  *
1454  * Return: 0 on success
1455  **/
1456 
1457 static int __init ip6_tunnel_init(void)
1458 {
1459 	int  err;
1460 
1461 	err = register_pernet_device(&ip6_tnl_net_ops);
1462 	if (err < 0)
1463 		goto out_pernet;
1464 
1465 	err = xfrm6_tunnel_register(&ip4ip6_handler, AF_INET);
1466 	if (err < 0) {
1467 		printk(KERN_ERR "ip6_tunnel init: can't register ip4ip6\n");
1468 		goto out_ip4ip6;
1469 	}
1470 
1471 	err = xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6);
1472 	if (err < 0) {
1473 		printk(KERN_ERR "ip6_tunnel init: can't register ip6ip6\n");
1474 		goto out_ip6ip6;
1475 	}
1476 
1477 	return 0;
1478 
1479 out_ip6ip6:
1480 	xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
1481 out_ip4ip6:
1482 	unregister_pernet_device(&ip6_tnl_net_ops);
1483 out_pernet:
1484 	return err;
1485 }
1486 
1487 /**
1488  * ip6_tunnel_cleanup - free resources and unregister protocol
1489  **/
1490 
1491 static void __exit ip6_tunnel_cleanup(void)
1492 {
1493 	if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))
1494 		printk(KERN_INFO "ip6_tunnel close: can't deregister ip4ip6\n");
1495 
1496 	if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))
1497 		printk(KERN_INFO "ip6_tunnel close: can't deregister ip6ip6\n");
1498 
1499 	unregister_pernet_device(&ip6_tnl_net_ops);
1500 }
1501 
1502 module_init(ip6_tunnel_init);
1503 module_exit(ip6_tunnel_cleanup);
1504