xref: /linux/net/ipv6/ip6_tunnel.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 
23 #include <linux/module.h>
24 #include <linux/capability.h>
25 #include <linux/errno.h>
26 #include <linux/types.h>
27 #include <linux/sockios.h>
28 #include <linux/icmp.h>
29 #include <linux/if.h>
30 #include <linux/in.h>
31 #include <linux/ip.h>
32 #include <linux/if_tunnel.h>
33 #include <linux/net.h>
34 #include <linux/in6.h>
35 #include <linux/netdevice.h>
36 #include <linux/if_arp.h>
37 #include <linux/icmpv6.h>
38 #include <linux/init.h>
39 #include <linux/route.h>
40 #include <linux/rtnetlink.h>
41 #include <linux/netfilter_ipv6.h>
42 #include <linux/slab.h>
43 #include <linux/hash.h>
44 
45 #include <asm/uaccess.h>
46 #include <linux/atomic.h>
47 
48 #include <net/icmp.h>
49 #include <net/ip.h>
50 #include <net/ipv6.h>
51 #include <net/ip6_route.h>
52 #include <net/addrconf.h>
53 #include <net/ip6_tunnel.h>
54 #include <net/xfrm.h>
55 #include <net/dsfield.h>
56 #include <net/inet_ecn.h>
57 #include <net/net_namespace.h>
58 #include <net/netns/generic.h>
59 
60 MODULE_AUTHOR("Ville Nuorvala");
61 MODULE_DESCRIPTION("IPv6 tunneling device");
62 MODULE_LICENSE("GPL");
63 MODULE_ALIAS_NETDEV("ip6tnl0");
64 
65 #ifdef IP6_TNL_DEBUG
66 #define IP6_TNL_TRACE(x...) pr_debug("%s:" x "\n", __func__)
67 #else
68 #define IP6_TNL_TRACE(x...) do {;} while(0)
69 #endif
70 
71 #define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)
72 #define IPV6_TCLASS_SHIFT 20
73 
74 #define HASH_SIZE_SHIFT  5
75 #define HASH_SIZE (1 << HASH_SIZE_SHIFT)
76 
77 static bool log_ecn_error = true;
78 module_param(log_ecn_error, bool, 0644);
79 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
80 
81 static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
82 {
83 	u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
84 
85 	return hash_32(hash, HASH_SIZE_SHIFT);
86 }
87 
88 static int ip6_tnl_dev_init(struct net_device *dev);
89 static void ip6_tnl_dev_setup(struct net_device *dev);
90 static struct rtnl_link_ops ip6_link_ops __read_mostly;
91 
92 static int ip6_tnl_net_id __read_mostly;
93 struct ip6_tnl_net {
94 	/* the IPv6 tunnel fallback device */
95 	struct net_device *fb_tnl_dev;
96 	/* lists for storing tunnels in use */
97 	struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE];
98 	struct ip6_tnl __rcu *tnls_wc[1];
99 	struct ip6_tnl __rcu **tnls[2];
100 };
101 
102 static struct net_device_stats *ip6_get_stats(struct net_device *dev)
103 {
104 	struct pcpu_tstats sum = { 0 };
105 	int i;
106 
107 	for_each_possible_cpu(i) {
108 		const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
109 
110 		sum.rx_packets += tstats->rx_packets;
111 		sum.rx_bytes   += tstats->rx_bytes;
112 		sum.tx_packets += tstats->tx_packets;
113 		sum.tx_bytes   += tstats->tx_bytes;
114 	}
115 	dev->stats.rx_packets = sum.rx_packets;
116 	dev->stats.rx_bytes   = sum.rx_bytes;
117 	dev->stats.tx_packets = sum.tx_packets;
118 	dev->stats.tx_bytes   = sum.tx_bytes;
119 	return &dev->stats;
120 }
121 
122 /*
123  * Locking : hash tables are protected by RCU and RTNL
124  */
125 
126 struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
127 {
128 	struct dst_entry *dst = t->dst_cache;
129 
130 	if (dst && dst->obsolete &&
131 	    dst->ops->check(dst, t->dst_cookie) == NULL) {
132 		t->dst_cache = NULL;
133 		dst_release(dst);
134 		return NULL;
135 	}
136 
137 	return dst;
138 }
139 EXPORT_SYMBOL_GPL(ip6_tnl_dst_check);
140 
141 void ip6_tnl_dst_reset(struct ip6_tnl *t)
142 {
143 	dst_release(t->dst_cache);
144 	t->dst_cache = NULL;
145 }
146 EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
147 
148 void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
149 {
150 	struct rt6_info *rt = (struct rt6_info *) dst;
151 	t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
152 	dst_release(t->dst_cache);
153 	t->dst_cache = dst;
154 }
155 EXPORT_SYMBOL_GPL(ip6_tnl_dst_store);
156 
157 /**
158  * ip6_tnl_lookup - fetch tunnel matching the end-point addresses
159  *   @remote: the address of the tunnel exit-point
160  *   @local: the address of the tunnel entry-point
161  *
162  * Return:
163  *   tunnel matching given end-points if found,
164  *   else fallback tunnel if its device is up,
165  *   else %NULL
166  **/
167 
168 #define for_each_ip6_tunnel_rcu(start) \
169 	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
170 
171 static struct ip6_tnl *
172 ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)
173 {
174 	unsigned int hash = HASH(remote, local);
175 	struct ip6_tnl *t;
176 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
177 
178 	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
179 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
180 		    ipv6_addr_equal(remote, &t->parms.raddr) &&
181 		    (t->dev->flags & IFF_UP))
182 			return t;
183 	}
184 	t = rcu_dereference(ip6n->tnls_wc[0]);
185 	if (t && (t->dev->flags & IFF_UP))
186 		return t;
187 
188 	return NULL;
189 }
190 
191 /**
192  * ip6_tnl_bucket - get head of list matching given tunnel parameters
193  *   @p: parameters containing tunnel end-points
194  *
195  * Description:
196  *   ip6_tnl_bucket() returns the head of the list matching the
197  *   &struct in6_addr entries laddr and raddr in @p.
198  *
199  * Return: head of IPv6 tunnel list
200  **/
201 
202 static struct ip6_tnl __rcu **
203 ip6_tnl_bucket(struct ip6_tnl_net *ip6n, const struct __ip6_tnl_parm *p)
204 {
205 	const struct in6_addr *remote = &p->raddr;
206 	const struct in6_addr *local = &p->laddr;
207 	unsigned int h = 0;
208 	int prio = 0;
209 
210 	if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
211 		prio = 1;
212 		h = HASH(remote, local);
213 	}
214 	return &ip6n->tnls[prio][h];
215 }
216 
217 /**
218  * ip6_tnl_link - add tunnel to hash table
219  *   @t: tunnel to be added
220  **/
221 
222 static void
223 ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
224 {
225 	struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms);
226 
227 	rcu_assign_pointer(t->next , rtnl_dereference(*tp));
228 	rcu_assign_pointer(*tp, t);
229 }
230 
231 /**
232  * ip6_tnl_unlink - remove tunnel from hash table
233  *   @t: tunnel to be removed
234  **/
235 
236 static void
237 ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
238 {
239 	struct ip6_tnl __rcu **tp;
240 	struct ip6_tnl *iter;
241 
242 	for (tp = ip6_tnl_bucket(ip6n, &t->parms);
243 	     (iter = rtnl_dereference(*tp)) != NULL;
244 	     tp = &iter->next) {
245 		if (t == iter) {
246 			rcu_assign_pointer(*tp, t->next);
247 			break;
248 		}
249 	}
250 }
251 
252 static void ip6_dev_free(struct net_device *dev)
253 {
254 	free_percpu(dev->tstats);
255 	free_netdev(dev);
256 }
257 
258 static int ip6_tnl_create2(struct net_device *dev)
259 {
260 	struct ip6_tnl *t = netdev_priv(dev);
261 	struct net *net = dev_net(dev);
262 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
263 	int err;
264 
265 	t = netdev_priv(dev);
266 	err = ip6_tnl_dev_init(dev);
267 	if (err < 0)
268 		goto out;
269 
270 	err = register_netdevice(dev);
271 	if (err < 0)
272 		goto out;
273 
274 	strcpy(t->parms.name, dev->name);
275 	dev->rtnl_link_ops = &ip6_link_ops;
276 
277 	dev_hold(dev);
278 	ip6_tnl_link(ip6n, t);
279 	return 0;
280 
281 out:
282 	return err;
283 }
284 
285 /**
286  * ip6_tnl_create - create a new tunnel
287  *   @p: tunnel parameters
288  *   @pt: pointer to new tunnel
289  *
290  * Description:
291  *   Create tunnel matching given parameters.
292  *
293  * Return:
294  *   created tunnel or NULL
295  **/
296 
297 static struct ip6_tnl *ip6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
298 {
299 	struct net_device *dev;
300 	struct ip6_tnl *t;
301 	char name[IFNAMSIZ];
302 	int err;
303 
304 	if (p->name[0])
305 		strlcpy(name, p->name, IFNAMSIZ);
306 	else
307 		sprintf(name, "ip6tnl%%d");
308 
309 	dev = alloc_netdev(sizeof (*t), name, ip6_tnl_dev_setup);
310 	if (dev == NULL)
311 		goto failed;
312 
313 	dev_net_set(dev, net);
314 
315 	t = netdev_priv(dev);
316 	t->parms = *p;
317 	err = ip6_tnl_create2(dev);
318 	if (err < 0)
319 		goto failed_free;
320 
321 	return t;
322 
323 failed_free:
324 	ip6_dev_free(dev);
325 failed:
326 	return NULL;
327 }
328 
329 /**
330  * ip6_tnl_locate - find or create tunnel matching given parameters
331  *   @p: tunnel parameters
332  *   @create: != 0 if allowed to create new tunnel if no match found
333  *
334  * Description:
335  *   ip6_tnl_locate() first tries to locate an existing tunnel
336  *   based on @parms. If this is unsuccessful, but @create is set a new
337  *   tunnel device is created and registered for use.
338  *
339  * Return:
340  *   matching tunnel or NULL
341  **/
342 
343 static struct ip6_tnl *ip6_tnl_locate(struct net *net,
344 		struct __ip6_tnl_parm *p, int create)
345 {
346 	const struct in6_addr *remote = &p->raddr;
347 	const struct in6_addr *local = &p->laddr;
348 	struct ip6_tnl __rcu **tp;
349 	struct ip6_tnl *t;
350 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
351 
352 	for (tp = ip6_tnl_bucket(ip6n, p);
353 	     (t = rtnl_dereference(*tp)) != NULL;
354 	     tp = &t->next) {
355 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
356 		    ipv6_addr_equal(remote, &t->parms.raddr))
357 			return t;
358 	}
359 	if (!create)
360 		return NULL;
361 	return ip6_tnl_create(net, p);
362 }
363 
364 /**
365  * ip6_tnl_dev_uninit - tunnel device uninitializer
366  *   @dev: the device to be destroyed
367  *
368  * Description:
369  *   ip6_tnl_dev_uninit() removes tunnel from its list
370  **/
371 
372 static void
373 ip6_tnl_dev_uninit(struct net_device *dev)
374 {
375 	struct ip6_tnl *t = netdev_priv(dev);
376 	struct net *net = dev_net(dev);
377 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
378 
379 	if (dev == ip6n->fb_tnl_dev)
380 		RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
381 	else
382 		ip6_tnl_unlink(ip6n, t);
383 	ip6_tnl_dst_reset(t);
384 	dev_put(dev);
385 }
386 
387 /**
388  * parse_tvl_tnl_enc_lim - handle encapsulation limit option
389  *   @skb: received socket buffer
390  *
391  * Return:
392  *   0 if none was found,
393  *   else index to encapsulation limit
394  **/
395 
396 __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
397 {
398 	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) raw;
399 	__u8 nexthdr = ipv6h->nexthdr;
400 	__u16 off = sizeof (*ipv6h);
401 
402 	while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
403 		__u16 optlen = 0;
404 		struct ipv6_opt_hdr *hdr;
405 		if (raw + off + sizeof (*hdr) > skb->data &&
406 		    !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
407 			break;
408 
409 		hdr = (struct ipv6_opt_hdr *) (raw + off);
410 		if (nexthdr == NEXTHDR_FRAGMENT) {
411 			struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
412 			if (frag_hdr->frag_off)
413 				break;
414 			optlen = 8;
415 		} else if (nexthdr == NEXTHDR_AUTH) {
416 			optlen = (hdr->hdrlen + 2) << 2;
417 		} else {
418 			optlen = ipv6_optlen(hdr);
419 		}
420 		if (nexthdr == NEXTHDR_DEST) {
421 			__u16 i = off + 2;
422 			while (1) {
423 				struct ipv6_tlv_tnl_enc_lim *tel;
424 
425 				/* No more room for encapsulation limit */
426 				if (i + sizeof (*tel) > off + optlen)
427 					break;
428 
429 				tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
430 				/* return index of option if found and valid */
431 				if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
432 				    tel->length == 1)
433 					return i;
434 				/* else jump to next option */
435 				if (tel->type)
436 					i += tel->length + 2;
437 				else
438 					i++;
439 			}
440 		}
441 		nexthdr = hdr->nexthdr;
442 		off += optlen;
443 	}
444 	return 0;
445 }
446 EXPORT_SYMBOL(ip6_tnl_parse_tlv_enc_lim);
447 
448 /**
449  * ip6_tnl_err - tunnel error handler
450  *
451  * Description:
452  *   ip6_tnl_err() should handle errors in the tunnel according
453  *   to the specifications in RFC 2473.
454  **/
455 
456 static int
457 ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
458 	    u8 *type, u8 *code, int *msg, __u32 *info, int offset)
459 {
460 	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) skb->data;
461 	struct ip6_tnl *t;
462 	int rel_msg = 0;
463 	u8 rel_type = ICMPV6_DEST_UNREACH;
464 	u8 rel_code = ICMPV6_ADDR_UNREACH;
465 	__u32 rel_info = 0;
466 	__u16 len;
467 	int err = -ENOENT;
468 
469 	/* If the packet doesn't contain the original IPv6 header we are
470 	   in trouble since we might need the source address for further
471 	   processing of the error. */
472 
473 	rcu_read_lock();
474 	if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr,
475 					&ipv6h->saddr)) == NULL)
476 		goto out;
477 
478 	if (t->parms.proto != ipproto && t->parms.proto != 0)
479 		goto out;
480 
481 	err = 0;
482 
483 	switch (*type) {
484 		__u32 teli;
485 		struct ipv6_tlv_tnl_enc_lim *tel;
486 		__u32 mtu;
487 	case ICMPV6_DEST_UNREACH:
488 		net_warn_ratelimited("%s: Path to destination invalid or inactive!\n",
489 				     t->parms.name);
490 		rel_msg = 1;
491 		break;
492 	case ICMPV6_TIME_EXCEED:
493 		if ((*code) == ICMPV6_EXC_HOPLIMIT) {
494 			net_warn_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
495 					     t->parms.name);
496 			rel_msg = 1;
497 		}
498 		break;
499 	case ICMPV6_PARAMPROB:
500 		teli = 0;
501 		if ((*code) == ICMPV6_HDR_FIELD)
502 			teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
503 
504 		if (teli && teli == *info - 2) {
505 			tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
506 			if (tel->encap_limit == 0) {
507 				net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
508 						     t->parms.name);
509 				rel_msg = 1;
510 			}
511 		} else {
512 			net_warn_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
513 					     t->parms.name);
514 		}
515 		break;
516 	case ICMPV6_PKT_TOOBIG:
517 		mtu = *info - offset;
518 		if (mtu < IPV6_MIN_MTU)
519 			mtu = IPV6_MIN_MTU;
520 		t->dev->mtu = mtu;
521 
522 		if ((len = sizeof (*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) {
523 			rel_type = ICMPV6_PKT_TOOBIG;
524 			rel_code = 0;
525 			rel_info = mtu;
526 			rel_msg = 1;
527 		}
528 		break;
529 	}
530 
531 	*type = rel_type;
532 	*code = rel_code;
533 	*info = rel_info;
534 	*msg = rel_msg;
535 
536 out:
537 	rcu_read_unlock();
538 	return err;
539 }
540 
541 static int
542 ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
543 	   u8 type, u8 code, int offset, __be32 info)
544 {
545 	int rel_msg = 0;
546 	u8 rel_type = type;
547 	u8 rel_code = code;
548 	__u32 rel_info = ntohl(info);
549 	int err;
550 	struct sk_buff *skb2;
551 	const struct iphdr *eiph;
552 	struct rtable *rt;
553 	struct flowi4 fl4;
554 
555 	err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
556 			  &rel_msg, &rel_info, offset);
557 	if (err < 0)
558 		return err;
559 
560 	if (rel_msg == 0)
561 		return 0;
562 
563 	switch (rel_type) {
564 	case ICMPV6_DEST_UNREACH:
565 		if (rel_code != ICMPV6_ADDR_UNREACH)
566 			return 0;
567 		rel_type = ICMP_DEST_UNREACH;
568 		rel_code = ICMP_HOST_UNREACH;
569 		break;
570 	case ICMPV6_PKT_TOOBIG:
571 		if (rel_code != 0)
572 			return 0;
573 		rel_type = ICMP_DEST_UNREACH;
574 		rel_code = ICMP_FRAG_NEEDED;
575 		break;
576 	case NDISC_REDIRECT:
577 		rel_type = ICMP_REDIRECT;
578 		rel_code = ICMP_REDIR_HOST;
579 	default:
580 		return 0;
581 	}
582 
583 	if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
584 		return 0;
585 
586 	skb2 = skb_clone(skb, GFP_ATOMIC);
587 	if (!skb2)
588 		return 0;
589 
590 	skb_dst_drop(skb2);
591 
592 	skb_pull(skb2, offset);
593 	skb_reset_network_header(skb2);
594 	eiph = ip_hdr(skb2);
595 
596 	/* Try to guess incoming interface */
597 	rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
598 				   eiph->saddr, 0,
599 				   0, 0,
600 				   IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
601 	if (IS_ERR(rt))
602 		goto out;
603 
604 	skb2->dev = rt->dst.dev;
605 
606 	/* route "incoming" packet */
607 	if (rt->rt_flags & RTCF_LOCAL) {
608 		ip_rt_put(rt);
609 		rt = NULL;
610 		rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
611 					   eiph->daddr, eiph->saddr,
612 					   0, 0,
613 					   IPPROTO_IPIP,
614 					   RT_TOS(eiph->tos), 0);
615 		if (IS_ERR(rt) ||
616 		    rt->dst.dev->type != ARPHRD_TUNNEL) {
617 			if (!IS_ERR(rt))
618 				ip_rt_put(rt);
619 			goto out;
620 		}
621 		skb_dst_set(skb2, &rt->dst);
622 	} else {
623 		ip_rt_put(rt);
624 		if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
625 				   skb2->dev) ||
626 		    skb_dst(skb2)->dev->type != ARPHRD_TUNNEL)
627 			goto out;
628 	}
629 
630 	/* change mtu on this route */
631 	if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {
632 		if (rel_info > dst_mtu(skb_dst(skb2)))
633 			goto out;
634 
635 		skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
636 	}
637 	if (rel_type == ICMP_REDIRECT)
638 		skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
639 
640 	icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
641 
642 out:
643 	kfree_skb(skb2);
644 	return 0;
645 }
646 
647 static int
648 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
649 	   u8 type, u8 code, int offset, __be32 info)
650 {
651 	int rel_msg = 0;
652 	u8 rel_type = type;
653 	u8 rel_code = code;
654 	__u32 rel_info = ntohl(info);
655 	int err;
656 
657 	err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
658 			  &rel_msg, &rel_info, offset);
659 	if (err < 0)
660 		return err;
661 
662 	if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) {
663 		struct rt6_info *rt;
664 		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
665 
666 		if (!skb2)
667 			return 0;
668 
669 		skb_dst_drop(skb2);
670 		skb_pull(skb2, offset);
671 		skb_reset_network_header(skb2);
672 
673 		/* Try to guess incoming interface */
674 		rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr,
675 				NULL, 0, 0);
676 
677 		if (rt && rt->dst.dev)
678 			skb2->dev = rt->dst.dev;
679 
680 		icmpv6_send(skb2, rel_type, rel_code, rel_info);
681 
682 		ip6_rt_put(rt);
683 
684 		kfree_skb(skb2);
685 	}
686 
687 	return 0;
688 }
689 
690 static int ip4ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
691 				       const struct ipv6hdr *ipv6h,
692 				       struct sk_buff *skb)
693 {
694 	__u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;
695 
696 	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
697 		ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield);
698 
699 	return IP6_ECN_decapsulate(ipv6h, skb);
700 }
701 
702 static int ip6ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
703 				       const struct ipv6hdr *ipv6h,
704 				       struct sk_buff *skb)
705 {
706 	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
707 		ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb));
708 
709 	return IP6_ECN_decapsulate(ipv6h, skb);
710 }
711 
712 __u32 ip6_tnl_get_cap(struct ip6_tnl *t,
713 			     const struct in6_addr *laddr,
714 			     const struct in6_addr *raddr)
715 {
716 	struct __ip6_tnl_parm *p = &t->parms;
717 	int ltype = ipv6_addr_type(laddr);
718 	int rtype = ipv6_addr_type(raddr);
719 	__u32 flags = 0;
720 
721 	if (ltype == IPV6_ADDR_ANY || rtype == IPV6_ADDR_ANY) {
722 		flags = IP6_TNL_F_CAP_PER_PACKET;
723 	} else if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
724 		   rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
725 		   !((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
726 		   (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
727 		if (ltype&IPV6_ADDR_UNICAST)
728 			flags |= IP6_TNL_F_CAP_XMIT;
729 		if (rtype&IPV6_ADDR_UNICAST)
730 			flags |= IP6_TNL_F_CAP_RCV;
731 	}
732 	return flags;
733 }
734 EXPORT_SYMBOL(ip6_tnl_get_cap);
735 
736 /* called with rcu_read_lock() */
737 int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
738 				  const struct in6_addr *laddr,
739 				  const struct in6_addr *raddr)
740 {
741 	struct __ip6_tnl_parm *p = &t->parms;
742 	int ret = 0;
743 	struct net *net = dev_net(t->dev);
744 
745 	if ((p->flags & IP6_TNL_F_CAP_RCV) ||
746 	    ((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
747 	     (ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_RCV))) {
748 		struct net_device *ldev = NULL;
749 
750 		if (p->link)
751 			ldev = dev_get_by_index_rcu(net, p->link);
752 
753 		if ((ipv6_addr_is_multicast(laddr) ||
754 		     likely(ipv6_chk_addr(net, laddr, ldev, 0))) &&
755 		    likely(!ipv6_chk_addr(net, raddr, NULL, 0)))
756 			ret = 1;
757 	}
758 	return ret;
759 }
760 EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
761 
762 /**
763  * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
764  *   @skb: received socket buffer
765  *   @protocol: ethernet protocol ID
766  *   @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
767  *
768  * Return: 0
769  **/
770 
771 static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
772 		       __u8 ipproto,
773 		       int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
774 						   const struct ipv6hdr *ipv6h,
775 						   struct sk_buff *skb))
776 {
777 	struct ip6_tnl *t;
778 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
779 	int err;
780 
781 	rcu_read_lock();
782 
783 	if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr,
784 					&ipv6h->daddr)) != NULL) {
785 		struct pcpu_tstats *tstats;
786 
787 		if (t->parms.proto != ipproto && t->parms.proto != 0) {
788 			rcu_read_unlock();
789 			goto discard;
790 		}
791 
792 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
793 			rcu_read_unlock();
794 			goto discard;
795 		}
796 
797 		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
798 			t->dev->stats.rx_dropped++;
799 			rcu_read_unlock();
800 			goto discard;
801 		}
802 		secpath_reset(skb);
803 		skb->mac_header = skb->network_header;
804 		skb_reset_network_header(skb);
805 		skb->protocol = htons(protocol);
806 		skb->pkt_type = PACKET_HOST;
807 		memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
808 
809 		__skb_tunnel_rx(skb, t->dev);
810 
811 		err = dscp_ecn_decapsulate(t, ipv6h, skb);
812 		if (unlikely(err)) {
813 			if (log_ecn_error)
814 				net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
815 						     &ipv6h->saddr,
816 						     ipv6_get_dsfield(ipv6h));
817 			if (err > 1) {
818 				++t->dev->stats.rx_frame_errors;
819 				++t->dev->stats.rx_errors;
820 				rcu_read_unlock();
821 				goto discard;
822 			}
823 		}
824 
825 		tstats = this_cpu_ptr(t->dev->tstats);
826 		tstats->rx_packets++;
827 		tstats->rx_bytes += skb->len;
828 
829 		netif_rx(skb);
830 
831 		rcu_read_unlock();
832 		return 0;
833 	}
834 	rcu_read_unlock();
835 	return 1;
836 
837 discard:
838 	kfree_skb(skb);
839 	return 0;
840 }
841 
842 static int ip4ip6_rcv(struct sk_buff *skb)
843 {
844 	return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
845 			   ip4ip6_dscp_ecn_decapsulate);
846 }
847 
848 static int ip6ip6_rcv(struct sk_buff *skb)
849 {
850 	return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
851 			   ip6ip6_dscp_ecn_decapsulate);
852 }
853 
854 struct ipv6_tel_txoption {
855 	struct ipv6_txoptions ops;
856 	__u8 dst_opt[8];
857 };
858 
859 static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
860 {
861 	memset(opt, 0, sizeof(struct ipv6_tel_txoption));
862 
863 	opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
864 	opt->dst_opt[3] = 1;
865 	opt->dst_opt[4] = encap_limit;
866 	opt->dst_opt[5] = IPV6_TLV_PADN;
867 	opt->dst_opt[6] = 1;
868 
869 	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
870 	opt->ops.opt_nflen = 8;
871 }
872 
873 /**
874  * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
875  *   @t: the outgoing tunnel device
876  *   @hdr: IPv6 header from the incoming packet
877  *
878  * Description:
879  *   Avoid trivial tunneling loop by checking that tunnel exit-point
880  *   doesn't match source of incoming packet.
881  *
882  * Return:
883  *   1 if conflict,
884  *   0 else
885  **/
886 
887 static inline bool
888 ip6_tnl_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
889 {
890 	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
891 }
892 
893 int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
894 {
895 	struct __ip6_tnl_parm *p = &t->parms;
896 	int ret = 0;
897 	struct net *net = dev_net(t->dev);
898 
899 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
900 		struct net_device *ldev = NULL;
901 
902 		rcu_read_lock();
903 		if (p->link)
904 			ldev = dev_get_by_index_rcu(net, p->link);
905 
906 		if (unlikely(!ipv6_chk_addr(net, &p->laddr, ldev, 0)))
907 			pr_warn("%s xmit: Local address not yet configured!\n",
908 				p->name);
909 		else if (!ipv6_addr_is_multicast(&p->raddr) &&
910 			 unlikely(ipv6_chk_addr(net, &p->raddr, NULL, 0)))
911 			pr_warn("%s xmit: Routing loop! Remote address found on this node!\n",
912 				p->name);
913 		else
914 			ret = 1;
915 		rcu_read_unlock();
916 	}
917 	return ret;
918 }
919 EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
920 
921 /**
922  * ip6_tnl_xmit2 - encapsulate packet and send
923  *   @skb: the outgoing socket buffer
924  *   @dev: the outgoing tunnel device
925  *   @dsfield: dscp code for outer header
926  *   @fl: flow of tunneled packet
927  *   @encap_limit: encapsulation limit
928  *   @pmtu: Path MTU is stored if packet is too big
929  *
930  * Description:
931  *   Build new header and do some sanity checks on the packet before sending
932  *   it.
933  *
934  * Return:
935  *   0 on success
936  *   -1 fail
937  *   %-EMSGSIZE message too big. return mtu in this case.
938  **/
939 
940 static int ip6_tnl_xmit2(struct sk_buff *skb,
941 			 struct net_device *dev,
942 			 __u8 dsfield,
943 			 struct flowi6 *fl6,
944 			 int encap_limit,
945 			 __u32 *pmtu)
946 {
947 	struct net *net = dev_net(dev);
948 	struct ip6_tnl *t = netdev_priv(dev);
949 	struct net_device_stats *stats = &t->dev->stats;
950 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
951 	struct ipv6_tel_txoption opt;
952 	struct dst_entry *dst = NULL, *ndst = NULL;
953 	struct net_device *tdev;
954 	int mtu;
955 	unsigned int max_headroom = sizeof(struct ipv6hdr);
956 	u8 proto;
957 	int err = -1;
958 	int pkt_len;
959 
960 	if (!fl6->flowi6_mark)
961 		dst = ip6_tnl_dst_check(t);
962 	if (!dst) {
963 		ndst = ip6_route_output(net, NULL, fl6);
964 
965 		if (ndst->error)
966 			goto tx_err_link_failure;
967 		ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0);
968 		if (IS_ERR(ndst)) {
969 			err = PTR_ERR(ndst);
970 			ndst = NULL;
971 			goto tx_err_link_failure;
972 		}
973 		dst = ndst;
974 	}
975 
976 	tdev = dst->dev;
977 
978 	if (tdev == dev) {
979 		stats->collisions++;
980 		net_warn_ratelimited("%s: Local routing loop detected!\n",
981 				     t->parms.name);
982 		goto tx_err_dst_release;
983 	}
984 	mtu = dst_mtu(dst) - sizeof (*ipv6h);
985 	if (encap_limit >= 0) {
986 		max_headroom += 8;
987 		mtu -= 8;
988 	}
989 	if (mtu < IPV6_MIN_MTU)
990 		mtu = IPV6_MIN_MTU;
991 	if (skb_dst(skb))
992 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
993 	if (skb->len > mtu) {
994 		*pmtu = mtu;
995 		err = -EMSGSIZE;
996 		goto tx_err_dst_release;
997 	}
998 
999 	/*
1000 	 * Okay, now see if we can stuff it in the buffer as-is.
1001 	 */
1002 	max_headroom += LL_RESERVED_SPACE(tdev);
1003 
1004 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1005 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1006 		struct sk_buff *new_skb;
1007 
1008 		if (!(new_skb = skb_realloc_headroom(skb, max_headroom)))
1009 			goto tx_err_dst_release;
1010 
1011 		if (skb->sk)
1012 			skb_set_owner_w(new_skb, skb->sk);
1013 		consume_skb(skb);
1014 		skb = new_skb;
1015 	}
1016 	skb_dst_drop(skb);
1017 	if (fl6->flowi6_mark) {
1018 		skb_dst_set(skb, dst);
1019 		ndst = NULL;
1020 	} else {
1021 		skb_dst_set_noref(skb, dst);
1022 	}
1023 	skb->transport_header = skb->network_header;
1024 
1025 	proto = fl6->flowi6_proto;
1026 	if (encap_limit >= 0) {
1027 		init_tel_txopt(&opt, encap_limit);
1028 		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
1029 	}
1030 	skb_push(skb, sizeof(struct ipv6hdr));
1031 	skb_reset_network_header(skb);
1032 	ipv6h = ipv6_hdr(skb);
1033 	*(__be32*)ipv6h = fl6->flowlabel | htonl(0x60000000);
1034 	dsfield = INET_ECN_encapsulate(0, dsfield);
1035 	ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
1036 	ipv6h->hop_limit = t->parms.hop_limit;
1037 	ipv6h->nexthdr = proto;
1038 	ipv6h->saddr = fl6->saddr;
1039 	ipv6h->daddr = fl6->daddr;
1040 	nf_reset(skb);
1041 	pkt_len = skb->len;
1042 	err = ip6_local_out(skb);
1043 
1044 	if (net_xmit_eval(err) == 0) {
1045 		struct pcpu_tstats *tstats = this_cpu_ptr(t->dev->tstats);
1046 
1047 		tstats->tx_bytes += pkt_len;
1048 		tstats->tx_packets++;
1049 	} else {
1050 		stats->tx_errors++;
1051 		stats->tx_aborted_errors++;
1052 	}
1053 	if (ndst)
1054 		ip6_tnl_dst_store(t, ndst);
1055 	return 0;
1056 tx_err_link_failure:
1057 	stats->tx_carrier_errors++;
1058 	dst_link_failure(skb);
1059 tx_err_dst_release:
1060 	dst_release(ndst);
1061 	return err;
1062 }
1063 
1064 static inline int
1065 ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1066 {
1067 	struct ip6_tnl *t = netdev_priv(dev);
1068 	const struct iphdr  *iph = ip_hdr(skb);
1069 	int encap_limit = -1;
1070 	struct flowi6 fl6;
1071 	__u8 dsfield;
1072 	__u32 mtu;
1073 	int err;
1074 
1075 	if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
1076 	    !ip6_tnl_xmit_ctl(t))
1077 		return -1;
1078 
1079 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1080 		encap_limit = t->parms.encap_limit;
1081 
1082 	memcpy(&fl6, &t->fl.u.ip6, sizeof (fl6));
1083 	fl6.flowi6_proto = IPPROTO_IPIP;
1084 
1085 	dsfield = ipv4_get_dsfield(iph);
1086 
1087 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
1088 		fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
1089 					  & IPV6_TCLASS_MASK;
1090 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
1091 		fl6.flowi6_mark = skb->mark;
1092 
1093 	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
1094 	if (err != 0) {
1095 		/* XXX: send ICMP error even if DF is not set. */
1096 		if (err == -EMSGSIZE)
1097 			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
1098 				  htonl(mtu));
1099 		return -1;
1100 	}
1101 
1102 	return 0;
1103 }
1104 
1105 static inline int
1106 ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1107 {
1108 	struct ip6_tnl *t = netdev_priv(dev);
1109 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
1110 	int encap_limit = -1;
1111 	__u16 offset;
1112 	struct flowi6 fl6;
1113 	__u8 dsfield;
1114 	__u32 mtu;
1115 	int err;
1116 
1117 	if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
1118 	    !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
1119 		return -1;
1120 
1121 	offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
1122 	if (offset > 0) {
1123 		struct ipv6_tlv_tnl_enc_lim *tel;
1124 		tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
1125 		if (tel->encap_limit == 0) {
1126 			icmpv6_send(skb, ICMPV6_PARAMPROB,
1127 				    ICMPV6_HDR_FIELD, offset + 2);
1128 			return -1;
1129 		}
1130 		encap_limit = tel->encap_limit - 1;
1131 	} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1132 		encap_limit = t->parms.encap_limit;
1133 
1134 	memcpy(&fl6, &t->fl.u.ip6, sizeof (fl6));
1135 	fl6.flowi6_proto = IPPROTO_IPV6;
1136 
1137 	dsfield = ipv6_get_dsfield(ipv6h);
1138 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
1139 		fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
1140 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
1141 		fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
1142 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
1143 		fl6.flowi6_mark = skb->mark;
1144 
1145 	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
1146 	if (err != 0) {
1147 		if (err == -EMSGSIZE)
1148 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1149 		return -1;
1150 	}
1151 
1152 	return 0;
1153 }
1154 
1155 static netdev_tx_t
1156 ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1157 {
1158 	struct ip6_tnl *t = netdev_priv(dev);
1159 	struct net_device_stats *stats = &t->dev->stats;
1160 	int ret;
1161 
1162 	switch (skb->protocol) {
1163 	case htons(ETH_P_IP):
1164 		ret = ip4ip6_tnl_xmit(skb, dev);
1165 		break;
1166 	case htons(ETH_P_IPV6):
1167 		ret = ip6ip6_tnl_xmit(skb, dev);
1168 		break;
1169 	default:
1170 		goto tx_err;
1171 	}
1172 
1173 	if (ret < 0)
1174 		goto tx_err;
1175 
1176 	return NETDEV_TX_OK;
1177 
1178 tx_err:
1179 	stats->tx_errors++;
1180 	stats->tx_dropped++;
1181 	kfree_skb(skb);
1182 	return NETDEV_TX_OK;
1183 }
1184 
1185 static void ip6_tnl_link_config(struct ip6_tnl *t)
1186 {
1187 	struct net_device *dev = t->dev;
1188 	struct __ip6_tnl_parm *p = &t->parms;
1189 	struct flowi6 *fl6 = &t->fl.u.ip6;
1190 
1191 	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
1192 	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
1193 
1194 	/* Set up flowi template */
1195 	fl6->saddr = p->laddr;
1196 	fl6->daddr = p->raddr;
1197 	fl6->flowi6_oif = p->link;
1198 	fl6->flowlabel = 0;
1199 
1200 	if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
1201 		fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
1202 	if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
1203 		fl6->flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
1204 
1205 	p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV|IP6_TNL_F_CAP_PER_PACKET);
1206 	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
1207 
1208 	if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
1209 		dev->flags |= IFF_POINTOPOINT;
1210 	else
1211 		dev->flags &= ~IFF_POINTOPOINT;
1212 
1213 	dev->iflink = p->link;
1214 
1215 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
1216 		int strict = (ipv6_addr_type(&p->raddr) &
1217 			      (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
1218 
1219 		struct rt6_info *rt = rt6_lookup(dev_net(dev),
1220 						 &p->raddr, &p->laddr,
1221 						 p->link, strict);
1222 
1223 		if (rt == NULL)
1224 			return;
1225 
1226 		if (rt->dst.dev) {
1227 			dev->hard_header_len = rt->dst.dev->hard_header_len +
1228 				sizeof (struct ipv6hdr);
1229 
1230 			dev->mtu = rt->dst.dev->mtu - sizeof (struct ipv6hdr);
1231 			if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1232 				dev->mtu-=8;
1233 
1234 			if (dev->mtu < IPV6_MIN_MTU)
1235 				dev->mtu = IPV6_MIN_MTU;
1236 		}
1237 		ip6_rt_put(rt);
1238 	}
1239 }
1240 
1241 /**
1242  * ip6_tnl_change - update the tunnel parameters
1243  *   @t: tunnel to be changed
1244  *   @p: tunnel configuration parameters
1245  *
1246  * Description:
1247  *   ip6_tnl_change() updates the tunnel parameters
1248  **/
1249 
1250 static int
1251 ip6_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p)
1252 {
1253 	t->parms.laddr = p->laddr;
1254 	t->parms.raddr = p->raddr;
1255 	t->parms.flags = p->flags;
1256 	t->parms.hop_limit = p->hop_limit;
1257 	t->parms.encap_limit = p->encap_limit;
1258 	t->parms.flowinfo = p->flowinfo;
1259 	t->parms.link = p->link;
1260 	t->parms.proto = p->proto;
1261 	ip6_tnl_dst_reset(t);
1262 	ip6_tnl_link_config(t);
1263 	return 0;
1264 }
1265 
1266 static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
1267 {
1268 	struct net *net = dev_net(t->dev);
1269 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1270 	int err;
1271 
1272 	ip6_tnl_unlink(ip6n, t);
1273 	synchronize_net();
1274 	err = ip6_tnl_change(t, p);
1275 	ip6_tnl_link(ip6n, t);
1276 	netdev_state_change(t->dev);
1277 	return err;
1278 }
1279 
1280 static void
1281 ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
1282 {
1283 	p->laddr = u->laddr;
1284 	p->raddr = u->raddr;
1285 	p->flags = u->flags;
1286 	p->hop_limit = u->hop_limit;
1287 	p->encap_limit = u->encap_limit;
1288 	p->flowinfo = u->flowinfo;
1289 	p->link = u->link;
1290 	p->proto = u->proto;
1291 	memcpy(p->name, u->name, sizeof(u->name));
1292 }
1293 
1294 static void
1295 ip6_tnl_parm_to_user(struct ip6_tnl_parm *u, const struct __ip6_tnl_parm *p)
1296 {
1297 	u->laddr = p->laddr;
1298 	u->raddr = p->raddr;
1299 	u->flags = p->flags;
1300 	u->hop_limit = p->hop_limit;
1301 	u->encap_limit = p->encap_limit;
1302 	u->flowinfo = p->flowinfo;
1303 	u->link = p->link;
1304 	u->proto = p->proto;
1305 	memcpy(u->name, p->name, sizeof(u->name));
1306 }
1307 
1308 /**
1309  * ip6_tnl_ioctl - configure ipv6 tunnels from userspace
1310  *   @dev: virtual device associated with tunnel
1311  *   @ifr: parameters passed from userspace
1312  *   @cmd: command to be performed
1313  *
1314  * Description:
1315  *   ip6_tnl_ioctl() is used for managing IPv6 tunnels
1316  *   from userspace.
1317  *
1318  *   The possible commands are the following:
1319  *     %SIOCGETTUNNEL: get tunnel parameters for device
1320  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
1321  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
1322  *     %SIOCDELTUNNEL: delete tunnel
1323  *
1324  *   The fallback device "ip6tnl0", created during module
1325  *   initialization, can be used for creating other tunnel devices.
1326  *
1327  * Return:
1328  *   0 on success,
1329  *   %-EFAULT if unable to copy data to or from userspace,
1330  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
1331  *   %-EINVAL if passed tunnel parameters are invalid,
1332  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
1333  *   %-ENODEV if attempting to change or delete a nonexisting device
1334  **/
1335 
1336 static int
1337 ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1338 {
1339 	int err = 0;
1340 	struct ip6_tnl_parm p;
1341 	struct __ip6_tnl_parm p1;
1342 	struct ip6_tnl *t = NULL;
1343 	struct net *net = dev_net(dev);
1344 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1345 
1346 	switch (cmd) {
1347 	case SIOCGETTUNNEL:
1348 		if (dev == ip6n->fb_tnl_dev) {
1349 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
1350 				err = -EFAULT;
1351 				break;
1352 			}
1353 			ip6_tnl_parm_from_user(&p1, &p);
1354 			t = ip6_tnl_locate(net, &p1, 0);
1355 		} else {
1356 			memset(&p, 0, sizeof(p));
1357 		}
1358 		if (t == NULL)
1359 			t = netdev_priv(dev);
1360 		ip6_tnl_parm_to_user(&p, &t->parms);
1361 		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof (p))) {
1362 			err = -EFAULT;
1363 		}
1364 		break;
1365 	case SIOCADDTUNNEL:
1366 	case SIOCCHGTUNNEL:
1367 		err = -EPERM;
1368 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1369 			break;
1370 		err = -EFAULT;
1371 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
1372 			break;
1373 		err = -EINVAL;
1374 		if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP &&
1375 		    p.proto != 0)
1376 			break;
1377 		ip6_tnl_parm_from_user(&p1, &p);
1378 		t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
1379 		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
1380 			if (t != NULL) {
1381 				if (t->dev != dev) {
1382 					err = -EEXIST;
1383 					break;
1384 				}
1385 			} else
1386 				t = netdev_priv(dev);
1387 
1388 			err = ip6_tnl_update(t, &p1);
1389 		}
1390 		if (t) {
1391 			err = 0;
1392 			ip6_tnl_parm_to_user(&p, &t->parms);
1393 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1394 				err = -EFAULT;
1395 
1396 		} else
1397 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1398 		break;
1399 	case SIOCDELTUNNEL:
1400 		err = -EPERM;
1401 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1402 			break;
1403 
1404 		if (dev == ip6n->fb_tnl_dev) {
1405 			err = -EFAULT;
1406 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
1407 				break;
1408 			err = -ENOENT;
1409 			ip6_tnl_parm_from_user(&p1, &p);
1410 			t = ip6_tnl_locate(net, &p1, 0);
1411 			if (t == NULL)
1412 				break;
1413 			err = -EPERM;
1414 			if (t->dev == ip6n->fb_tnl_dev)
1415 				break;
1416 			dev = t->dev;
1417 		}
1418 		err = 0;
1419 		unregister_netdevice(dev);
1420 		break;
1421 	default:
1422 		err = -EINVAL;
1423 	}
1424 	return err;
1425 }
1426 
1427 /**
1428  * ip6_tnl_change_mtu - change mtu manually for tunnel device
1429  *   @dev: virtual device associated with tunnel
1430  *   @new_mtu: the new mtu
1431  *
1432  * Return:
1433  *   0 on success,
1434  *   %-EINVAL if mtu too small
1435  **/
1436 
1437 static int
1438 ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
1439 {
1440 	if (new_mtu < IPV6_MIN_MTU) {
1441 		return -EINVAL;
1442 	}
1443 	dev->mtu = new_mtu;
1444 	return 0;
1445 }
1446 
1447 
1448 static const struct net_device_ops ip6_tnl_netdev_ops = {
1449 	.ndo_uninit	= ip6_tnl_dev_uninit,
1450 	.ndo_start_xmit = ip6_tnl_xmit,
1451 	.ndo_do_ioctl	= ip6_tnl_ioctl,
1452 	.ndo_change_mtu = ip6_tnl_change_mtu,
1453 	.ndo_get_stats	= ip6_get_stats,
1454 };
1455 
1456 
1457 /**
1458  * ip6_tnl_dev_setup - setup virtual tunnel device
1459  *   @dev: virtual device associated with tunnel
1460  *
1461  * Description:
1462  *   Initialize function pointers and device parameters
1463  **/
1464 
1465 static void ip6_tnl_dev_setup(struct net_device *dev)
1466 {
1467 	struct ip6_tnl *t;
1468 
1469 	dev->netdev_ops = &ip6_tnl_netdev_ops;
1470 	dev->destructor = ip6_dev_free;
1471 
1472 	dev->type = ARPHRD_TUNNEL6;
1473 	dev->hard_header_len = LL_MAX_HEADER + sizeof (struct ipv6hdr);
1474 	dev->mtu = ETH_DATA_LEN - sizeof (struct ipv6hdr);
1475 	t = netdev_priv(dev);
1476 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1477 		dev->mtu-=8;
1478 	dev->flags |= IFF_NOARP;
1479 	dev->addr_len = sizeof(struct in6_addr);
1480 	dev->features |= NETIF_F_NETNS_LOCAL;
1481 	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1482 }
1483 
1484 
1485 /**
1486  * ip6_tnl_dev_init_gen - general initializer for all tunnel devices
1487  *   @dev: virtual device associated with tunnel
1488  **/
1489 
1490 static inline int
1491 ip6_tnl_dev_init_gen(struct net_device *dev)
1492 {
1493 	struct ip6_tnl *t = netdev_priv(dev);
1494 
1495 	t->dev = dev;
1496 	dev->tstats = alloc_percpu(struct pcpu_tstats);
1497 	if (!dev->tstats)
1498 		return -ENOMEM;
1499 	return 0;
1500 }
1501 
1502 /**
1503  * ip6_tnl_dev_init - initializer for all non fallback tunnel devices
1504  *   @dev: virtual device associated with tunnel
1505  **/
1506 
1507 static int ip6_tnl_dev_init(struct net_device *dev)
1508 {
1509 	struct ip6_tnl *t = netdev_priv(dev);
1510 	int err = ip6_tnl_dev_init_gen(dev);
1511 
1512 	if (err)
1513 		return err;
1514 	ip6_tnl_link_config(t);
1515 	return 0;
1516 }
1517 
1518 /**
1519  * ip6_fb_tnl_dev_init - initializer for fallback tunnel device
1520  *   @dev: fallback device
1521  *
1522  * Return: 0
1523  **/
1524 
1525 static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
1526 {
1527 	struct ip6_tnl *t = netdev_priv(dev);
1528 	struct net *net = dev_net(dev);
1529 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1530 	int err = ip6_tnl_dev_init_gen(dev);
1531 
1532 	if (err)
1533 		return err;
1534 
1535 	t->parms.proto = IPPROTO_IPV6;
1536 	dev_hold(dev);
1537 
1538 	ip6_tnl_link_config(t);
1539 
1540 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
1541 	return 0;
1542 }
1543 
1544 static int ip6_tnl_validate(struct nlattr *tb[], struct nlattr *data[])
1545 {
1546 	u8 proto;
1547 
1548 	if (!data)
1549 		return 0;
1550 
1551 	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1552 	if (proto != IPPROTO_IPV6 &&
1553 	    proto != IPPROTO_IPIP &&
1554 	    proto != 0)
1555 		return -EINVAL;
1556 
1557 	return 0;
1558 }
1559 
1560 static void ip6_tnl_netlink_parms(struct nlattr *data[],
1561 				  struct __ip6_tnl_parm *parms)
1562 {
1563 	memset(parms, 0, sizeof(*parms));
1564 
1565 	if (!data)
1566 		return;
1567 
1568 	if (data[IFLA_IPTUN_LINK])
1569 		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1570 
1571 	if (data[IFLA_IPTUN_LOCAL])
1572 		nla_memcpy(&parms->laddr, data[IFLA_IPTUN_LOCAL],
1573 			   sizeof(struct in6_addr));
1574 
1575 	if (data[IFLA_IPTUN_REMOTE])
1576 		nla_memcpy(&parms->raddr, data[IFLA_IPTUN_REMOTE],
1577 			   sizeof(struct in6_addr));
1578 
1579 	if (data[IFLA_IPTUN_TTL])
1580 		parms->hop_limit = nla_get_u8(data[IFLA_IPTUN_TTL]);
1581 
1582 	if (data[IFLA_IPTUN_ENCAP_LIMIT])
1583 		parms->encap_limit = nla_get_u8(data[IFLA_IPTUN_ENCAP_LIMIT]);
1584 
1585 	if (data[IFLA_IPTUN_FLOWINFO])
1586 		parms->flowinfo = nla_get_be32(data[IFLA_IPTUN_FLOWINFO]);
1587 
1588 	if (data[IFLA_IPTUN_FLAGS])
1589 		parms->flags = nla_get_u32(data[IFLA_IPTUN_FLAGS]);
1590 
1591 	if (data[IFLA_IPTUN_PROTO])
1592 		parms->proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1593 }
1594 
1595 static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
1596 			   struct nlattr *tb[], struct nlattr *data[])
1597 {
1598 	struct net *net = dev_net(dev);
1599 	struct ip6_tnl *nt;
1600 
1601 	nt = netdev_priv(dev);
1602 	ip6_tnl_netlink_parms(data, &nt->parms);
1603 
1604 	if (ip6_tnl_locate(net, &nt->parms, 0))
1605 		return -EEXIST;
1606 
1607 	return ip6_tnl_create2(dev);
1608 }
1609 
1610 static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[],
1611 			      struct nlattr *data[])
1612 {
1613 	struct ip6_tnl *t;
1614 	struct __ip6_tnl_parm p;
1615 	struct net *net = dev_net(dev);
1616 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1617 
1618 	if (dev == ip6n->fb_tnl_dev)
1619 		return -EINVAL;
1620 
1621 	ip6_tnl_netlink_parms(data, &p);
1622 
1623 	t = ip6_tnl_locate(net, &p, 0);
1624 
1625 	if (t) {
1626 		if (t->dev != dev)
1627 			return -EEXIST;
1628 	} else
1629 		t = netdev_priv(dev);
1630 
1631 	return ip6_tnl_update(t, &p);
1632 }
1633 
1634 static size_t ip6_tnl_get_size(const struct net_device *dev)
1635 {
1636 	return
1637 		/* IFLA_IPTUN_LINK */
1638 		nla_total_size(4) +
1639 		/* IFLA_IPTUN_LOCAL */
1640 		nla_total_size(sizeof(struct in6_addr)) +
1641 		/* IFLA_IPTUN_REMOTE */
1642 		nla_total_size(sizeof(struct in6_addr)) +
1643 		/* IFLA_IPTUN_TTL */
1644 		nla_total_size(1) +
1645 		/* IFLA_IPTUN_ENCAP_LIMIT */
1646 		nla_total_size(1) +
1647 		/* IFLA_IPTUN_FLOWINFO */
1648 		nla_total_size(4) +
1649 		/* IFLA_IPTUN_FLAGS */
1650 		nla_total_size(4) +
1651 		/* IFLA_IPTUN_PROTO */
1652 		nla_total_size(1) +
1653 		0;
1654 }
1655 
1656 static int ip6_tnl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1657 {
1658 	struct ip6_tnl *tunnel = netdev_priv(dev);
1659 	struct __ip6_tnl_parm *parm = &tunnel->parms;
1660 
1661 	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1662 	    nla_put(skb, IFLA_IPTUN_LOCAL, sizeof(struct in6_addr),
1663 		    &parm->raddr) ||
1664 	    nla_put(skb, IFLA_IPTUN_REMOTE, sizeof(struct in6_addr),
1665 		    &parm->laddr) ||
1666 	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->hop_limit) ||
1667 	    nla_put_u8(skb, IFLA_IPTUN_ENCAP_LIMIT, parm->encap_limit) ||
1668 	    nla_put_be32(skb, IFLA_IPTUN_FLOWINFO, parm->flowinfo) ||
1669 	    nla_put_u32(skb, IFLA_IPTUN_FLAGS, parm->flags) ||
1670 	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto))
1671 		goto nla_put_failure;
1672 	return 0;
1673 
1674 nla_put_failure:
1675 	return -EMSGSIZE;
1676 }
1677 
1678 static const struct nla_policy ip6_tnl_policy[IFLA_IPTUN_MAX + 1] = {
1679 	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
1680 	[IFLA_IPTUN_LOCAL]		= { .len = sizeof(struct in6_addr) },
1681 	[IFLA_IPTUN_REMOTE]		= { .len = sizeof(struct in6_addr) },
1682 	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
1683 	[IFLA_IPTUN_ENCAP_LIMIT]	= { .type = NLA_U8 },
1684 	[IFLA_IPTUN_FLOWINFO]		= { .type = NLA_U32 },
1685 	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U32 },
1686 	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
1687 };
1688 
1689 static struct rtnl_link_ops ip6_link_ops __read_mostly = {
1690 	.kind		= "ip6tnl",
1691 	.maxtype	= IFLA_IPTUN_MAX,
1692 	.policy		= ip6_tnl_policy,
1693 	.priv_size	= sizeof(struct ip6_tnl),
1694 	.setup		= ip6_tnl_dev_setup,
1695 	.validate	= ip6_tnl_validate,
1696 	.newlink	= ip6_tnl_newlink,
1697 	.changelink	= ip6_tnl_changelink,
1698 	.get_size	= ip6_tnl_get_size,
1699 	.fill_info	= ip6_tnl_fill_info,
1700 };
1701 
1702 static struct xfrm6_tunnel ip4ip6_handler __read_mostly = {
1703 	.handler	= ip4ip6_rcv,
1704 	.err_handler	= ip4ip6_err,
1705 	.priority	=	1,
1706 };
1707 
1708 static struct xfrm6_tunnel ip6ip6_handler __read_mostly = {
1709 	.handler	= ip6ip6_rcv,
1710 	.err_handler	= ip6ip6_err,
1711 	.priority	=	1,
1712 };
1713 
1714 static void __net_exit ip6_tnl_destroy_tunnels(struct ip6_tnl_net *ip6n)
1715 {
1716 	int h;
1717 	struct ip6_tnl *t;
1718 	LIST_HEAD(list);
1719 
1720 	for (h = 0; h < HASH_SIZE; h++) {
1721 		t = rtnl_dereference(ip6n->tnls_r_l[h]);
1722 		while (t != NULL) {
1723 			unregister_netdevice_queue(t->dev, &list);
1724 			t = rtnl_dereference(t->next);
1725 		}
1726 	}
1727 
1728 	t = rtnl_dereference(ip6n->tnls_wc[0]);
1729 	unregister_netdevice_queue(t->dev, &list);
1730 	unregister_netdevice_many(&list);
1731 }
1732 
1733 static int __net_init ip6_tnl_init_net(struct net *net)
1734 {
1735 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1736 	struct ip6_tnl *t = NULL;
1737 	int err;
1738 
1739 	ip6n->tnls[0] = ip6n->tnls_wc;
1740 	ip6n->tnls[1] = ip6n->tnls_r_l;
1741 
1742 	err = -ENOMEM;
1743 	ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
1744 				      ip6_tnl_dev_setup);
1745 
1746 	if (!ip6n->fb_tnl_dev)
1747 		goto err_alloc_dev;
1748 	dev_net_set(ip6n->fb_tnl_dev, net);
1749 
1750 	err = ip6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
1751 	if (err < 0)
1752 		goto err_register;
1753 
1754 	err = register_netdev(ip6n->fb_tnl_dev);
1755 	if (err < 0)
1756 		goto err_register;
1757 
1758 	t = netdev_priv(ip6n->fb_tnl_dev);
1759 
1760 	strcpy(t->parms.name, ip6n->fb_tnl_dev->name);
1761 	return 0;
1762 
1763 err_register:
1764 	ip6_dev_free(ip6n->fb_tnl_dev);
1765 err_alloc_dev:
1766 	return err;
1767 }
1768 
1769 static void __net_exit ip6_tnl_exit_net(struct net *net)
1770 {
1771 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1772 
1773 	rtnl_lock();
1774 	ip6_tnl_destroy_tunnels(ip6n);
1775 	rtnl_unlock();
1776 }
1777 
1778 static struct pernet_operations ip6_tnl_net_ops = {
1779 	.init = ip6_tnl_init_net,
1780 	.exit = ip6_tnl_exit_net,
1781 	.id   = &ip6_tnl_net_id,
1782 	.size = sizeof(struct ip6_tnl_net),
1783 };
1784 
1785 /**
1786  * ip6_tunnel_init - register protocol and reserve needed resources
1787  *
1788  * Return: 0 on success
1789  **/
1790 
1791 static int __init ip6_tunnel_init(void)
1792 {
1793 	int  err;
1794 
1795 	err = register_pernet_device(&ip6_tnl_net_ops);
1796 	if (err < 0)
1797 		goto out_pernet;
1798 
1799 	err = xfrm6_tunnel_register(&ip4ip6_handler, AF_INET);
1800 	if (err < 0) {
1801 		pr_err("%s: can't register ip4ip6\n", __func__);
1802 		goto out_ip4ip6;
1803 	}
1804 
1805 	err = xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6);
1806 	if (err < 0) {
1807 		pr_err("%s: can't register ip6ip6\n", __func__);
1808 		goto out_ip6ip6;
1809 	}
1810 	err = rtnl_link_register(&ip6_link_ops);
1811 	if (err < 0)
1812 		goto rtnl_link_failed;
1813 
1814 	return 0;
1815 
1816 rtnl_link_failed:
1817 	xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6);
1818 out_ip6ip6:
1819 	xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
1820 out_ip4ip6:
1821 	unregister_pernet_device(&ip6_tnl_net_ops);
1822 out_pernet:
1823 	return err;
1824 }
1825 
1826 /**
1827  * ip6_tunnel_cleanup - free resources and unregister protocol
1828  **/
1829 
1830 static void __exit ip6_tunnel_cleanup(void)
1831 {
1832 	rtnl_link_unregister(&ip6_link_ops);
1833 	if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))
1834 		pr_info("%s: can't deregister ip4ip6\n", __func__);
1835 
1836 	if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))
1837 		pr_info("%s: can't deregister ip6ip6\n", __func__);
1838 
1839 	unregister_pernet_device(&ip6_tnl_net_ops);
1840 }
1841 
1842 module_init(ip6_tunnel_init);
1843 module_exit(ip6_tunnel_cleanup);
1844