xref: /openbmc/linux/net/ipv6/ip6_tunnel.c (revision 3c6a73cc)
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/net.h>
33 #include <linux/in6.h>
34 #include <linux/netdevice.h>
35 #include <linux/if_arp.h>
36 #include <linux/icmpv6.h>
37 #include <linux/init.h>
38 #include <linux/route.h>
39 #include <linux/rtnetlink.h>
40 #include <linux/netfilter_ipv6.h>
41 #include <linux/slab.h>
42 #include <linux/hash.h>
43 #include <linux/etherdevice.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/ip_tunnels.h>
51 #include <net/ipv6.h>
52 #include <net/ip6_route.h>
53 #include <net/addrconf.h>
54 #include <net/ip6_tunnel.h>
55 #include <net/xfrm.h>
56 #include <net/dsfield.h>
57 #include <net/inet_ecn.h>
58 #include <net/net_namespace.h>
59 #include <net/netns/generic.h>
60 
61 MODULE_AUTHOR("Ville Nuorvala");
62 MODULE_DESCRIPTION("IPv6 tunneling device");
63 MODULE_LICENSE("GPL");
64 MODULE_ALIAS_RTNL_LINK("ip6tnl");
65 MODULE_ALIAS_NETDEV("ip6tnl0");
66 
67 #ifdef IP6_TNL_DEBUG
68 #define IP6_TNL_TRACE(x...) pr_debug("%s:" x "\n", __func__)
69 #else
70 #define IP6_TNL_TRACE(x...) do {;} while(0)
71 #endif
72 
73 #define HASH_SIZE_SHIFT  5
74 #define HASH_SIZE (1 << HASH_SIZE_SHIFT)
75 
76 static bool log_ecn_error = true;
77 module_param(log_ecn_error, bool, 0644);
78 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
79 
80 static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
81 {
82 	u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
83 
84 	return hash_32(hash, HASH_SIZE_SHIFT);
85 }
86 
87 static int ip6_tnl_dev_init(struct net_device *dev);
88 static void ip6_tnl_dev_setup(struct net_device *dev);
89 static struct rtnl_link_ops ip6_link_ops __read_mostly;
90 
91 static int ip6_tnl_net_id __read_mostly;
92 struct ip6_tnl_net {
93 	/* the IPv6 tunnel fallback device */
94 	struct net_device *fb_tnl_dev;
95 	/* lists for storing tunnels in use */
96 	struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE];
97 	struct ip6_tnl __rcu *tnls_wc[1];
98 	struct ip6_tnl __rcu **tnls[2];
99 };
100 
101 static struct net_device_stats *ip6_get_stats(struct net_device *dev)
102 {
103 	struct pcpu_sw_netstats tmp, sum = { 0 };
104 	int i;
105 
106 	for_each_possible_cpu(i) {
107 		unsigned int start;
108 		const struct pcpu_sw_netstats *tstats =
109 						   per_cpu_ptr(dev->tstats, i);
110 
111 		do {
112 			start = u64_stats_fetch_begin_irq(&tstats->syncp);
113 			tmp.rx_packets = tstats->rx_packets;
114 			tmp.rx_bytes = tstats->rx_bytes;
115 			tmp.tx_packets = tstats->tx_packets;
116 			tmp.tx_bytes =  tstats->tx_bytes;
117 		} while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
118 
119 		sum.rx_packets += tmp.rx_packets;
120 		sum.rx_bytes   += tmp.rx_bytes;
121 		sum.tx_packets += tmp.tx_packets;
122 		sum.tx_bytes   += tmp.tx_bytes;
123 	}
124 	dev->stats.rx_packets = sum.rx_packets;
125 	dev->stats.rx_bytes   = sum.rx_bytes;
126 	dev->stats.tx_packets = sum.tx_packets;
127 	dev->stats.tx_bytes   = sum.tx_bytes;
128 	return &dev->stats;
129 }
130 
131 /*
132  * Locking : hash tables are protected by RCU and RTNL
133  */
134 
135 struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
136 {
137 	struct dst_entry *dst = t->dst_cache;
138 
139 	if (dst && dst->obsolete &&
140 	    dst->ops->check(dst, t->dst_cookie) == NULL) {
141 		t->dst_cache = NULL;
142 		dst_release(dst);
143 		return NULL;
144 	}
145 
146 	return dst;
147 }
148 EXPORT_SYMBOL_GPL(ip6_tnl_dst_check);
149 
150 void ip6_tnl_dst_reset(struct ip6_tnl *t)
151 {
152 	dst_release(t->dst_cache);
153 	t->dst_cache = NULL;
154 }
155 EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
156 
157 void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
158 {
159 	struct rt6_info *rt = (struct rt6_info *) dst;
160 	t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
161 	dst_release(t->dst_cache);
162 	t->dst_cache = dst;
163 }
164 EXPORT_SYMBOL_GPL(ip6_tnl_dst_store);
165 
166 /**
167  * ip6_tnl_lookup - fetch tunnel matching the end-point addresses
168  *   @remote: the address of the tunnel exit-point
169  *   @local: the address of the tunnel entry-point
170  *
171  * Return:
172  *   tunnel matching given end-points if found,
173  *   else fallback tunnel if its device is up,
174  *   else %NULL
175  **/
176 
177 #define for_each_ip6_tunnel_rcu(start) \
178 	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
179 
180 static struct ip6_tnl *
181 ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)
182 {
183 	unsigned int hash = HASH(remote, local);
184 	struct ip6_tnl *t;
185 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
186 
187 	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
188 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
189 		    ipv6_addr_equal(remote, &t->parms.raddr) &&
190 		    (t->dev->flags & IFF_UP))
191 			return t;
192 	}
193 	t = rcu_dereference(ip6n->tnls_wc[0]);
194 	if (t && (t->dev->flags & IFF_UP))
195 		return t;
196 
197 	return NULL;
198 }
199 
200 /**
201  * ip6_tnl_bucket - get head of list matching given tunnel parameters
202  *   @p: parameters containing tunnel end-points
203  *
204  * Description:
205  *   ip6_tnl_bucket() returns the head of the list matching the
206  *   &struct in6_addr entries laddr and raddr in @p.
207  *
208  * Return: head of IPv6 tunnel list
209  **/
210 
211 static struct ip6_tnl __rcu **
212 ip6_tnl_bucket(struct ip6_tnl_net *ip6n, const struct __ip6_tnl_parm *p)
213 {
214 	const struct in6_addr *remote = &p->raddr;
215 	const struct in6_addr *local = &p->laddr;
216 	unsigned int h = 0;
217 	int prio = 0;
218 
219 	if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
220 		prio = 1;
221 		h = HASH(remote, local);
222 	}
223 	return &ip6n->tnls[prio][h];
224 }
225 
226 /**
227  * ip6_tnl_link - add tunnel to hash table
228  *   @t: tunnel to be added
229  **/
230 
231 static void
232 ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
233 {
234 	struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms);
235 
236 	rcu_assign_pointer(t->next , rtnl_dereference(*tp));
237 	rcu_assign_pointer(*tp, t);
238 }
239 
240 /**
241  * ip6_tnl_unlink - remove tunnel from hash table
242  *   @t: tunnel to be removed
243  **/
244 
245 static void
246 ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
247 {
248 	struct ip6_tnl __rcu **tp;
249 	struct ip6_tnl *iter;
250 
251 	for (tp = ip6_tnl_bucket(ip6n, &t->parms);
252 	     (iter = rtnl_dereference(*tp)) != NULL;
253 	     tp = &iter->next) {
254 		if (t == iter) {
255 			rcu_assign_pointer(*tp, t->next);
256 			break;
257 		}
258 	}
259 }
260 
261 static void ip6_dev_free(struct net_device *dev)
262 {
263 	free_percpu(dev->tstats);
264 	free_netdev(dev);
265 }
266 
267 static int ip6_tnl_create2(struct net_device *dev)
268 {
269 	struct ip6_tnl *t = netdev_priv(dev);
270 	struct net *net = dev_net(dev);
271 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
272 	int err;
273 
274 	t = netdev_priv(dev);
275 	err = ip6_tnl_dev_init(dev);
276 	if (err < 0)
277 		goto out;
278 
279 	err = register_netdevice(dev);
280 	if (err < 0)
281 		goto out;
282 
283 	strcpy(t->parms.name, dev->name);
284 	dev->rtnl_link_ops = &ip6_link_ops;
285 
286 	dev_hold(dev);
287 	ip6_tnl_link(ip6n, t);
288 	return 0;
289 
290 out:
291 	return err;
292 }
293 
294 /**
295  * ip6_tnl_create - create a new tunnel
296  *   @p: tunnel parameters
297  *   @pt: pointer to new tunnel
298  *
299  * Description:
300  *   Create tunnel matching given parameters.
301  *
302  * Return:
303  *   created tunnel or NULL
304  **/
305 
306 static struct ip6_tnl *ip6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
307 {
308 	struct net_device *dev;
309 	struct ip6_tnl *t;
310 	char name[IFNAMSIZ];
311 	int err;
312 
313 	if (p->name[0])
314 		strlcpy(name, p->name, IFNAMSIZ);
315 	else
316 		sprintf(name, "ip6tnl%%d");
317 
318 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
319 			   ip6_tnl_dev_setup);
320 	if (dev == NULL)
321 		goto failed;
322 
323 	dev_net_set(dev, net);
324 
325 	t = netdev_priv(dev);
326 	t->parms = *p;
327 	t->net = dev_net(dev);
328 	err = ip6_tnl_create2(dev);
329 	if (err < 0)
330 		goto failed_free;
331 
332 	return t;
333 
334 failed_free:
335 	ip6_dev_free(dev);
336 failed:
337 	return NULL;
338 }
339 
340 /**
341  * ip6_tnl_locate - find or create tunnel matching given parameters
342  *   @p: tunnel parameters
343  *   @create: != 0 if allowed to create new tunnel if no match found
344  *
345  * Description:
346  *   ip6_tnl_locate() first tries to locate an existing tunnel
347  *   based on @parms. If this is unsuccessful, but @create is set a new
348  *   tunnel device is created and registered for use.
349  *
350  * Return:
351  *   matching tunnel or NULL
352  **/
353 
354 static struct ip6_tnl *ip6_tnl_locate(struct net *net,
355 		struct __ip6_tnl_parm *p, int create)
356 {
357 	const struct in6_addr *remote = &p->raddr;
358 	const struct in6_addr *local = &p->laddr;
359 	struct ip6_tnl __rcu **tp;
360 	struct ip6_tnl *t;
361 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
362 
363 	for (tp = ip6_tnl_bucket(ip6n, p);
364 	     (t = rtnl_dereference(*tp)) != NULL;
365 	     tp = &t->next) {
366 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
367 		    ipv6_addr_equal(remote, &t->parms.raddr)) {
368 			if (create)
369 				return NULL;
370 
371 			return t;
372 		}
373 	}
374 	if (!create)
375 		return NULL;
376 	return ip6_tnl_create(net, p);
377 }
378 
379 /**
380  * ip6_tnl_dev_uninit - tunnel device uninitializer
381  *   @dev: the device to be destroyed
382  *
383  * Description:
384  *   ip6_tnl_dev_uninit() removes tunnel from its list
385  **/
386 
387 static void
388 ip6_tnl_dev_uninit(struct net_device *dev)
389 {
390 	struct ip6_tnl *t = netdev_priv(dev);
391 	struct net *net = t->net;
392 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
393 
394 	if (dev == ip6n->fb_tnl_dev)
395 		RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
396 	else
397 		ip6_tnl_unlink(ip6n, t);
398 	ip6_tnl_dst_reset(t);
399 	dev_put(dev);
400 }
401 
402 /**
403  * parse_tvl_tnl_enc_lim - handle encapsulation limit option
404  *   @skb: received socket buffer
405  *
406  * Return:
407  *   0 if none was found,
408  *   else index to encapsulation limit
409  **/
410 
411 __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
412 {
413 	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) raw;
414 	__u8 nexthdr = ipv6h->nexthdr;
415 	__u16 off = sizeof(*ipv6h);
416 
417 	while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
418 		__u16 optlen = 0;
419 		struct ipv6_opt_hdr *hdr;
420 		if (raw + off + sizeof(*hdr) > skb->data &&
421 		    !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
422 			break;
423 
424 		hdr = (struct ipv6_opt_hdr *) (raw + off);
425 		if (nexthdr == NEXTHDR_FRAGMENT) {
426 			struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
427 			if (frag_hdr->frag_off)
428 				break;
429 			optlen = 8;
430 		} else if (nexthdr == NEXTHDR_AUTH) {
431 			optlen = (hdr->hdrlen + 2) << 2;
432 		} else {
433 			optlen = ipv6_optlen(hdr);
434 		}
435 		if (nexthdr == NEXTHDR_DEST) {
436 			__u16 i = off + 2;
437 			while (1) {
438 				struct ipv6_tlv_tnl_enc_lim *tel;
439 
440 				/* No more room for encapsulation limit */
441 				if (i + sizeof (*tel) > off + optlen)
442 					break;
443 
444 				tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
445 				/* return index of option if found and valid */
446 				if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
447 				    tel->length == 1)
448 					return i;
449 				/* else jump to next option */
450 				if (tel->type)
451 					i += tel->length + 2;
452 				else
453 					i++;
454 			}
455 		}
456 		nexthdr = hdr->nexthdr;
457 		off += optlen;
458 	}
459 	return 0;
460 }
461 EXPORT_SYMBOL(ip6_tnl_parse_tlv_enc_lim);
462 
463 /**
464  * ip6_tnl_err - tunnel error handler
465  *
466  * Description:
467  *   ip6_tnl_err() should handle errors in the tunnel according
468  *   to the specifications in RFC 2473.
469  **/
470 
471 static int
472 ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
473 	    u8 *type, u8 *code, int *msg, __u32 *info, int offset)
474 {
475 	const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) skb->data;
476 	struct ip6_tnl *t;
477 	int rel_msg = 0;
478 	u8 rel_type = ICMPV6_DEST_UNREACH;
479 	u8 rel_code = ICMPV6_ADDR_UNREACH;
480 	__u32 rel_info = 0;
481 	__u16 len;
482 	int err = -ENOENT;
483 
484 	/* If the packet doesn't contain the original IPv6 header we are
485 	   in trouble since we might need the source address for further
486 	   processing of the error. */
487 
488 	rcu_read_lock();
489 	if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr,
490 					&ipv6h->saddr)) == NULL)
491 		goto out;
492 
493 	if (t->parms.proto != ipproto && t->parms.proto != 0)
494 		goto out;
495 
496 	err = 0;
497 
498 	switch (*type) {
499 		__u32 teli;
500 		struct ipv6_tlv_tnl_enc_lim *tel;
501 		__u32 mtu;
502 	case ICMPV6_DEST_UNREACH:
503 		net_warn_ratelimited("%s: Path to destination invalid or inactive!\n",
504 				     t->parms.name);
505 		rel_msg = 1;
506 		break;
507 	case ICMPV6_TIME_EXCEED:
508 		if ((*code) == ICMPV6_EXC_HOPLIMIT) {
509 			net_warn_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
510 					     t->parms.name);
511 			rel_msg = 1;
512 		}
513 		break;
514 	case ICMPV6_PARAMPROB:
515 		teli = 0;
516 		if ((*code) == ICMPV6_HDR_FIELD)
517 			teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
518 
519 		if (teli && teli == *info - 2) {
520 			tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
521 			if (tel->encap_limit == 0) {
522 				net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
523 						     t->parms.name);
524 				rel_msg = 1;
525 			}
526 		} else {
527 			net_warn_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
528 					     t->parms.name);
529 		}
530 		break;
531 	case ICMPV6_PKT_TOOBIG:
532 		mtu = *info - offset;
533 		if (mtu < IPV6_MIN_MTU)
534 			mtu = IPV6_MIN_MTU;
535 		t->dev->mtu = mtu;
536 
537 		if ((len = sizeof(*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) {
538 			rel_type = ICMPV6_PKT_TOOBIG;
539 			rel_code = 0;
540 			rel_info = mtu;
541 			rel_msg = 1;
542 		}
543 		break;
544 	}
545 
546 	*type = rel_type;
547 	*code = rel_code;
548 	*info = rel_info;
549 	*msg = rel_msg;
550 
551 out:
552 	rcu_read_unlock();
553 	return err;
554 }
555 
556 static int
557 ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
558 	   u8 type, u8 code, int offset, __be32 info)
559 {
560 	int rel_msg = 0;
561 	u8 rel_type = type;
562 	u8 rel_code = code;
563 	__u32 rel_info = ntohl(info);
564 	int err;
565 	struct sk_buff *skb2;
566 	const struct iphdr *eiph;
567 	struct rtable *rt;
568 	struct flowi4 fl4;
569 
570 	err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
571 			  &rel_msg, &rel_info, offset);
572 	if (err < 0)
573 		return err;
574 
575 	if (rel_msg == 0)
576 		return 0;
577 
578 	switch (rel_type) {
579 	case ICMPV6_DEST_UNREACH:
580 		if (rel_code != ICMPV6_ADDR_UNREACH)
581 			return 0;
582 		rel_type = ICMP_DEST_UNREACH;
583 		rel_code = ICMP_HOST_UNREACH;
584 		break;
585 	case ICMPV6_PKT_TOOBIG:
586 		if (rel_code != 0)
587 			return 0;
588 		rel_type = ICMP_DEST_UNREACH;
589 		rel_code = ICMP_FRAG_NEEDED;
590 		break;
591 	case NDISC_REDIRECT:
592 		rel_type = ICMP_REDIRECT;
593 		rel_code = ICMP_REDIR_HOST;
594 	default:
595 		return 0;
596 	}
597 
598 	if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
599 		return 0;
600 
601 	skb2 = skb_clone(skb, GFP_ATOMIC);
602 	if (!skb2)
603 		return 0;
604 
605 	skb_dst_drop(skb2);
606 
607 	skb_pull(skb2, offset);
608 	skb_reset_network_header(skb2);
609 	eiph = ip_hdr(skb2);
610 
611 	/* Try to guess incoming interface */
612 	rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
613 				   eiph->saddr, 0,
614 				   0, 0,
615 				   IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
616 	if (IS_ERR(rt))
617 		goto out;
618 
619 	skb2->dev = rt->dst.dev;
620 
621 	/* route "incoming" packet */
622 	if (rt->rt_flags & RTCF_LOCAL) {
623 		ip_rt_put(rt);
624 		rt = NULL;
625 		rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
626 					   eiph->daddr, eiph->saddr,
627 					   0, 0,
628 					   IPPROTO_IPIP,
629 					   RT_TOS(eiph->tos), 0);
630 		if (IS_ERR(rt) ||
631 		    rt->dst.dev->type != ARPHRD_TUNNEL) {
632 			if (!IS_ERR(rt))
633 				ip_rt_put(rt);
634 			goto out;
635 		}
636 		skb_dst_set(skb2, &rt->dst);
637 	} else {
638 		ip_rt_put(rt);
639 		if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
640 				   skb2->dev) ||
641 		    skb_dst(skb2)->dev->type != ARPHRD_TUNNEL)
642 			goto out;
643 	}
644 
645 	/* change mtu on this route */
646 	if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {
647 		if (rel_info > dst_mtu(skb_dst(skb2)))
648 			goto out;
649 
650 		skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
651 	}
652 	if (rel_type == ICMP_REDIRECT)
653 		skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
654 
655 	icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
656 
657 out:
658 	kfree_skb(skb2);
659 	return 0;
660 }
661 
662 static int
663 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
664 	   u8 type, u8 code, int offset, __be32 info)
665 {
666 	int rel_msg = 0;
667 	u8 rel_type = type;
668 	u8 rel_code = code;
669 	__u32 rel_info = ntohl(info);
670 	int err;
671 
672 	err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
673 			  &rel_msg, &rel_info, offset);
674 	if (err < 0)
675 		return err;
676 
677 	if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) {
678 		struct rt6_info *rt;
679 		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
680 
681 		if (!skb2)
682 			return 0;
683 
684 		skb_dst_drop(skb2);
685 		skb_pull(skb2, offset);
686 		skb_reset_network_header(skb2);
687 
688 		/* Try to guess incoming interface */
689 		rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr,
690 				NULL, 0, 0);
691 
692 		if (rt && rt->dst.dev)
693 			skb2->dev = rt->dst.dev;
694 
695 		icmpv6_send(skb2, rel_type, rel_code, rel_info);
696 
697 		ip6_rt_put(rt);
698 
699 		kfree_skb(skb2);
700 	}
701 
702 	return 0;
703 }
704 
705 static int ip4ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
706 				       const struct ipv6hdr *ipv6h,
707 				       struct sk_buff *skb)
708 {
709 	__u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;
710 
711 	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
712 		ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield);
713 
714 	return IP6_ECN_decapsulate(ipv6h, skb);
715 }
716 
717 static int ip6ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
718 				       const struct ipv6hdr *ipv6h,
719 				       struct sk_buff *skb)
720 {
721 	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
722 		ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb));
723 
724 	return IP6_ECN_decapsulate(ipv6h, skb);
725 }
726 
727 __u32 ip6_tnl_get_cap(struct ip6_tnl *t,
728 			     const struct in6_addr *laddr,
729 			     const struct in6_addr *raddr)
730 {
731 	struct __ip6_tnl_parm *p = &t->parms;
732 	int ltype = ipv6_addr_type(laddr);
733 	int rtype = ipv6_addr_type(raddr);
734 	__u32 flags = 0;
735 
736 	if (ltype == IPV6_ADDR_ANY || rtype == IPV6_ADDR_ANY) {
737 		flags = IP6_TNL_F_CAP_PER_PACKET;
738 	} else if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
739 		   rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
740 		   !((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
741 		   (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
742 		if (ltype&IPV6_ADDR_UNICAST)
743 			flags |= IP6_TNL_F_CAP_XMIT;
744 		if (rtype&IPV6_ADDR_UNICAST)
745 			flags |= IP6_TNL_F_CAP_RCV;
746 	}
747 	return flags;
748 }
749 EXPORT_SYMBOL(ip6_tnl_get_cap);
750 
751 /* called with rcu_read_lock() */
752 int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
753 				  const struct in6_addr *laddr,
754 				  const struct in6_addr *raddr)
755 {
756 	struct __ip6_tnl_parm *p = &t->parms;
757 	int ret = 0;
758 	struct net *net = t->net;
759 
760 	if ((p->flags & IP6_TNL_F_CAP_RCV) ||
761 	    ((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
762 	     (ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_RCV))) {
763 		struct net_device *ldev = NULL;
764 
765 		if (p->link)
766 			ldev = dev_get_by_index_rcu(net, p->link);
767 
768 		if ((ipv6_addr_is_multicast(laddr) ||
769 		     likely(ipv6_chk_addr(net, laddr, ldev, 0))) &&
770 		    likely(!ipv6_chk_addr(net, raddr, NULL, 0)))
771 			ret = 1;
772 	}
773 	return ret;
774 }
775 EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
776 
777 /**
778  * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
779  *   @skb: received socket buffer
780  *   @protocol: ethernet protocol ID
781  *   @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
782  *
783  * Return: 0
784  **/
785 
786 static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
787 		       __u8 ipproto,
788 		       int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
789 						   const struct ipv6hdr *ipv6h,
790 						   struct sk_buff *skb))
791 {
792 	struct ip6_tnl *t;
793 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
794 	int err;
795 
796 	rcu_read_lock();
797 
798 	if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr,
799 					&ipv6h->daddr)) != NULL) {
800 		struct pcpu_sw_netstats *tstats;
801 
802 		if (t->parms.proto != ipproto && t->parms.proto != 0) {
803 			rcu_read_unlock();
804 			goto discard;
805 		}
806 
807 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
808 			rcu_read_unlock();
809 			goto discard;
810 		}
811 
812 		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
813 			t->dev->stats.rx_dropped++;
814 			rcu_read_unlock();
815 			goto discard;
816 		}
817 		skb->mac_header = skb->network_header;
818 		skb_reset_network_header(skb);
819 		skb->protocol = htons(protocol);
820 		memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
821 
822 		__skb_tunnel_rx(skb, t->dev, t->net);
823 
824 		err = dscp_ecn_decapsulate(t, ipv6h, skb);
825 		if (unlikely(err)) {
826 			if (log_ecn_error)
827 				net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
828 						     &ipv6h->saddr,
829 						     ipv6_get_dsfield(ipv6h));
830 			if (err > 1) {
831 				++t->dev->stats.rx_frame_errors;
832 				++t->dev->stats.rx_errors;
833 				rcu_read_unlock();
834 				goto discard;
835 			}
836 		}
837 
838 		tstats = this_cpu_ptr(t->dev->tstats);
839 		u64_stats_update_begin(&tstats->syncp);
840 		tstats->rx_packets++;
841 		tstats->rx_bytes += skb->len;
842 		u64_stats_update_end(&tstats->syncp);
843 
844 		netif_rx(skb);
845 
846 		rcu_read_unlock();
847 		return 0;
848 	}
849 	rcu_read_unlock();
850 	return 1;
851 
852 discard:
853 	kfree_skb(skb);
854 	return 0;
855 }
856 
857 static int ip4ip6_rcv(struct sk_buff *skb)
858 {
859 	return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
860 			   ip4ip6_dscp_ecn_decapsulate);
861 }
862 
863 static int ip6ip6_rcv(struct sk_buff *skb)
864 {
865 	return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
866 			   ip6ip6_dscp_ecn_decapsulate);
867 }
868 
869 struct ipv6_tel_txoption {
870 	struct ipv6_txoptions ops;
871 	__u8 dst_opt[8];
872 };
873 
874 static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
875 {
876 	memset(opt, 0, sizeof(struct ipv6_tel_txoption));
877 
878 	opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
879 	opt->dst_opt[3] = 1;
880 	opt->dst_opt[4] = encap_limit;
881 	opt->dst_opt[5] = IPV6_TLV_PADN;
882 	opt->dst_opt[6] = 1;
883 
884 	opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
885 	opt->ops.opt_nflen = 8;
886 }
887 
888 /**
889  * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
890  *   @t: the outgoing tunnel device
891  *   @hdr: IPv6 header from the incoming packet
892  *
893  * Description:
894  *   Avoid trivial tunneling loop by checking that tunnel exit-point
895  *   doesn't match source of incoming packet.
896  *
897  * Return:
898  *   1 if conflict,
899  *   0 else
900  **/
901 
902 static inline bool
903 ip6_tnl_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
904 {
905 	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
906 }
907 
908 int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
909 {
910 	struct __ip6_tnl_parm *p = &t->parms;
911 	int ret = 0;
912 	struct net *net = t->net;
913 
914 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
915 		struct net_device *ldev = NULL;
916 
917 		rcu_read_lock();
918 		if (p->link)
919 			ldev = dev_get_by_index_rcu(net, p->link);
920 
921 		if (unlikely(!ipv6_chk_addr(net, &p->laddr, ldev, 0)))
922 			pr_warn("%s xmit: Local address not yet configured!\n",
923 				p->name);
924 		else if (!ipv6_addr_is_multicast(&p->raddr) &&
925 			 unlikely(ipv6_chk_addr(net, &p->raddr, NULL, 0)))
926 			pr_warn("%s xmit: Routing loop! Remote address found on this node!\n",
927 				p->name);
928 		else
929 			ret = 1;
930 		rcu_read_unlock();
931 	}
932 	return ret;
933 }
934 EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
935 
936 /**
937  * ip6_tnl_xmit2 - encapsulate packet and send
938  *   @skb: the outgoing socket buffer
939  *   @dev: the outgoing tunnel device
940  *   @dsfield: dscp code for outer header
941  *   @fl: flow of tunneled packet
942  *   @encap_limit: encapsulation limit
943  *   @pmtu: Path MTU is stored if packet is too big
944  *
945  * Description:
946  *   Build new header and do some sanity checks on the packet before sending
947  *   it.
948  *
949  * Return:
950  *   0 on success
951  *   -1 fail
952  *   %-EMSGSIZE message too big. return mtu in this case.
953  **/
954 
955 static int ip6_tnl_xmit2(struct sk_buff *skb,
956 			 struct net_device *dev,
957 			 __u8 dsfield,
958 			 struct flowi6 *fl6,
959 			 int encap_limit,
960 			 __u32 *pmtu)
961 {
962 	struct ip6_tnl *t = netdev_priv(dev);
963 	struct net *net = t->net;
964 	struct net_device_stats *stats = &t->dev->stats;
965 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
966 	struct ipv6_tel_txoption opt;
967 	struct dst_entry *dst = NULL, *ndst = NULL;
968 	struct net_device *tdev;
969 	int mtu;
970 	unsigned int max_headroom = sizeof(struct ipv6hdr);
971 	u8 proto;
972 	int err = -1;
973 
974 	if (!fl6->flowi6_mark)
975 		dst = ip6_tnl_dst_check(t);
976 	if (!dst) {
977 		ndst = ip6_route_output(net, NULL, fl6);
978 
979 		if (ndst->error)
980 			goto tx_err_link_failure;
981 		ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0);
982 		if (IS_ERR(ndst)) {
983 			err = PTR_ERR(ndst);
984 			ndst = NULL;
985 			goto tx_err_link_failure;
986 		}
987 		dst = ndst;
988 	}
989 
990 	tdev = dst->dev;
991 
992 	if (tdev == dev) {
993 		stats->collisions++;
994 		net_warn_ratelimited("%s: Local routing loop detected!\n",
995 				     t->parms.name);
996 		goto tx_err_dst_release;
997 	}
998 	mtu = dst_mtu(dst) - sizeof(*ipv6h);
999 	if (encap_limit >= 0) {
1000 		max_headroom += 8;
1001 		mtu -= 8;
1002 	}
1003 	if (mtu < IPV6_MIN_MTU)
1004 		mtu = IPV6_MIN_MTU;
1005 	if (skb_dst(skb))
1006 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
1007 	if (skb->len > mtu) {
1008 		*pmtu = mtu;
1009 		err = -EMSGSIZE;
1010 		goto tx_err_dst_release;
1011 	}
1012 
1013 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
1014 
1015 	/*
1016 	 * Okay, now see if we can stuff it in the buffer as-is.
1017 	 */
1018 	max_headroom += LL_RESERVED_SPACE(tdev);
1019 
1020 	if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1021 	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1022 		struct sk_buff *new_skb;
1023 
1024 		if (!(new_skb = skb_realloc_headroom(skb, max_headroom)))
1025 			goto tx_err_dst_release;
1026 
1027 		if (skb->sk)
1028 			skb_set_owner_w(new_skb, skb->sk);
1029 		consume_skb(skb);
1030 		skb = new_skb;
1031 	}
1032 	if (fl6->flowi6_mark) {
1033 		skb_dst_set(skb, dst);
1034 		ndst = NULL;
1035 	} else {
1036 		skb_dst_set_noref(skb, dst);
1037 	}
1038 	skb->transport_header = skb->network_header;
1039 
1040 	proto = fl6->flowi6_proto;
1041 	if (encap_limit >= 0) {
1042 		init_tel_txopt(&opt, encap_limit);
1043 		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
1044 	}
1045 
1046 	if (likely(!skb->encapsulation)) {
1047 		skb_reset_inner_headers(skb);
1048 		skb->encapsulation = 1;
1049 	}
1050 
1051 	skb_push(skb, sizeof(struct ipv6hdr));
1052 	skb_reset_network_header(skb);
1053 	ipv6h = ipv6_hdr(skb);
1054 	ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
1055 		     ip6_make_flowlabel(net, skb, fl6->flowlabel, false));
1056 	ipv6h->hop_limit = t->parms.hop_limit;
1057 	ipv6h->nexthdr = proto;
1058 	ipv6h->saddr = fl6->saddr;
1059 	ipv6h->daddr = fl6->daddr;
1060 	ip6tunnel_xmit(skb, dev);
1061 	if (ndst)
1062 		ip6_tnl_dst_store(t, ndst);
1063 	return 0;
1064 tx_err_link_failure:
1065 	stats->tx_carrier_errors++;
1066 	dst_link_failure(skb);
1067 tx_err_dst_release:
1068 	dst_release(ndst);
1069 	return err;
1070 }
1071 
1072 static inline int
1073 ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1074 {
1075 	struct ip6_tnl *t = netdev_priv(dev);
1076 	const struct iphdr  *iph = ip_hdr(skb);
1077 	int encap_limit = -1;
1078 	struct flowi6 fl6;
1079 	__u8 dsfield;
1080 	__u32 mtu;
1081 	int err;
1082 
1083 	if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) ||
1084 	    !ip6_tnl_xmit_ctl(t))
1085 		return -1;
1086 
1087 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1088 		encap_limit = t->parms.encap_limit;
1089 
1090 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
1091 	fl6.flowi6_proto = IPPROTO_IPIP;
1092 
1093 	dsfield = ipv4_get_dsfield(iph);
1094 
1095 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
1096 		fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
1097 					  & IPV6_TCLASS_MASK;
1098 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
1099 		fl6.flowi6_mark = skb->mark;
1100 
1101 	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
1102 	if (err != 0) {
1103 		/* XXX: send ICMP error even if DF is not set. */
1104 		if (err == -EMSGSIZE)
1105 			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
1106 				  htonl(mtu));
1107 		return -1;
1108 	}
1109 
1110 	return 0;
1111 }
1112 
1113 static inline int
1114 ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1115 {
1116 	struct ip6_tnl *t = netdev_priv(dev);
1117 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
1118 	int encap_limit = -1;
1119 	__u16 offset;
1120 	struct flowi6 fl6;
1121 	__u8 dsfield;
1122 	__u32 mtu;
1123 	int err;
1124 
1125 	if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
1126 	    !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h))
1127 		return -1;
1128 
1129 	offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
1130 	if (offset > 0) {
1131 		struct ipv6_tlv_tnl_enc_lim *tel;
1132 		tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
1133 		if (tel->encap_limit == 0) {
1134 			icmpv6_send(skb, ICMPV6_PARAMPROB,
1135 				    ICMPV6_HDR_FIELD, offset + 2);
1136 			return -1;
1137 		}
1138 		encap_limit = tel->encap_limit - 1;
1139 	} else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1140 		encap_limit = t->parms.encap_limit;
1141 
1142 	memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
1143 	fl6.flowi6_proto = IPPROTO_IPV6;
1144 
1145 	dsfield = ipv6_get_dsfield(ipv6h);
1146 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
1147 		fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
1148 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
1149 		fl6.flowlabel |= ip6_flowlabel(ipv6h);
1150 	if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
1151 		fl6.flowi6_mark = skb->mark;
1152 
1153 	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
1154 	if (err != 0) {
1155 		if (err == -EMSGSIZE)
1156 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1157 		return -1;
1158 	}
1159 
1160 	return 0;
1161 }
1162 
1163 static netdev_tx_t
1164 ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1165 {
1166 	struct ip6_tnl *t = netdev_priv(dev);
1167 	struct net_device_stats *stats = &t->dev->stats;
1168 	int ret;
1169 
1170 	switch (skb->protocol) {
1171 	case htons(ETH_P_IP):
1172 		ret = ip4ip6_tnl_xmit(skb, dev);
1173 		break;
1174 	case htons(ETH_P_IPV6):
1175 		ret = ip6ip6_tnl_xmit(skb, dev);
1176 		break;
1177 	default:
1178 		goto tx_err;
1179 	}
1180 
1181 	if (ret < 0)
1182 		goto tx_err;
1183 
1184 	return NETDEV_TX_OK;
1185 
1186 tx_err:
1187 	stats->tx_errors++;
1188 	stats->tx_dropped++;
1189 	kfree_skb(skb);
1190 	return NETDEV_TX_OK;
1191 }
1192 
1193 static void ip6_tnl_link_config(struct ip6_tnl *t)
1194 {
1195 	struct net_device *dev = t->dev;
1196 	struct __ip6_tnl_parm *p = &t->parms;
1197 	struct flowi6 *fl6 = &t->fl.u.ip6;
1198 
1199 	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
1200 	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
1201 
1202 	/* Set up flowi template */
1203 	fl6->saddr = p->laddr;
1204 	fl6->daddr = p->raddr;
1205 	fl6->flowi6_oif = p->link;
1206 	fl6->flowlabel = 0;
1207 
1208 	if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
1209 		fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
1210 	if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
1211 		fl6->flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
1212 
1213 	p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV|IP6_TNL_F_CAP_PER_PACKET);
1214 	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
1215 
1216 	if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
1217 		dev->flags |= IFF_POINTOPOINT;
1218 	else
1219 		dev->flags &= ~IFF_POINTOPOINT;
1220 
1221 	dev->iflink = p->link;
1222 
1223 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
1224 		int strict = (ipv6_addr_type(&p->raddr) &
1225 			      (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
1226 
1227 		struct rt6_info *rt = rt6_lookup(t->net,
1228 						 &p->raddr, &p->laddr,
1229 						 p->link, strict);
1230 
1231 		if (rt == NULL)
1232 			return;
1233 
1234 		if (rt->dst.dev) {
1235 			dev->hard_header_len = rt->dst.dev->hard_header_len +
1236 				sizeof(struct ipv6hdr);
1237 
1238 			dev->mtu = rt->dst.dev->mtu - sizeof(struct ipv6hdr);
1239 			if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1240 				dev->mtu -= 8;
1241 
1242 			if (dev->mtu < IPV6_MIN_MTU)
1243 				dev->mtu = IPV6_MIN_MTU;
1244 		}
1245 		ip6_rt_put(rt);
1246 	}
1247 }
1248 
1249 /**
1250  * ip6_tnl_change - update the tunnel parameters
1251  *   @t: tunnel to be changed
1252  *   @p: tunnel configuration parameters
1253  *
1254  * Description:
1255  *   ip6_tnl_change() updates the tunnel parameters
1256  **/
1257 
1258 static int
1259 ip6_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p)
1260 {
1261 	t->parms.laddr = p->laddr;
1262 	t->parms.raddr = p->raddr;
1263 	t->parms.flags = p->flags;
1264 	t->parms.hop_limit = p->hop_limit;
1265 	t->parms.encap_limit = p->encap_limit;
1266 	t->parms.flowinfo = p->flowinfo;
1267 	t->parms.link = p->link;
1268 	t->parms.proto = p->proto;
1269 	ip6_tnl_dst_reset(t);
1270 	ip6_tnl_link_config(t);
1271 	return 0;
1272 }
1273 
1274 static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
1275 {
1276 	struct net *net = t->net;
1277 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1278 	int err;
1279 
1280 	ip6_tnl_unlink(ip6n, t);
1281 	synchronize_net();
1282 	err = ip6_tnl_change(t, p);
1283 	ip6_tnl_link(ip6n, t);
1284 	netdev_state_change(t->dev);
1285 	return err;
1286 }
1287 
1288 static void
1289 ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
1290 {
1291 	p->laddr = u->laddr;
1292 	p->raddr = u->raddr;
1293 	p->flags = u->flags;
1294 	p->hop_limit = u->hop_limit;
1295 	p->encap_limit = u->encap_limit;
1296 	p->flowinfo = u->flowinfo;
1297 	p->link = u->link;
1298 	p->proto = u->proto;
1299 	memcpy(p->name, u->name, sizeof(u->name));
1300 }
1301 
1302 static void
1303 ip6_tnl_parm_to_user(struct ip6_tnl_parm *u, const struct __ip6_tnl_parm *p)
1304 {
1305 	u->laddr = p->laddr;
1306 	u->raddr = p->raddr;
1307 	u->flags = p->flags;
1308 	u->hop_limit = p->hop_limit;
1309 	u->encap_limit = p->encap_limit;
1310 	u->flowinfo = p->flowinfo;
1311 	u->link = p->link;
1312 	u->proto = p->proto;
1313 	memcpy(u->name, p->name, sizeof(u->name));
1314 }
1315 
1316 /**
1317  * ip6_tnl_ioctl - configure ipv6 tunnels from userspace
1318  *   @dev: virtual device associated with tunnel
1319  *   @ifr: parameters passed from userspace
1320  *   @cmd: command to be performed
1321  *
1322  * Description:
1323  *   ip6_tnl_ioctl() is used for managing IPv6 tunnels
1324  *   from userspace.
1325  *
1326  *   The possible commands are the following:
1327  *     %SIOCGETTUNNEL: get tunnel parameters for device
1328  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
1329  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
1330  *     %SIOCDELTUNNEL: delete tunnel
1331  *
1332  *   The fallback device "ip6tnl0", created during module
1333  *   initialization, can be used for creating other tunnel devices.
1334  *
1335  * Return:
1336  *   0 on success,
1337  *   %-EFAULT if unable to copy data to or from userspace,
1338  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
1339  *   %-EINVAL if passed tunnel parameters are invalid,
1340  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
1341  *   %-ENODEV if attempting to change or delete a nonexisting device
1342  **/
1343 
1344 static int
1345 ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1346 {
1347 	int err = 0;
1348 	struct ip6_tnl_parm p;
1349 	struct __ip6_tnl_parm p1;
1350 	struct ip6_tnl *t = netdev_priv(dev);
1351 	struct net *net = t->net;
1352 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1353 
1354 	switch (cmd) {
1355 	case SIOCGETTUNNEL:
1356 		if (dev == ip6n->fb_tnl_dev) {
1357 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1358 				err = -EFAULT;
1359 				break;
1360 			}
1361 			ip6_tnl_parm_from_user(&p1, &p);
1362 			t = ip6_tnl_locate(net, &p1, 0);
1363 			if (t == NULL)
1364 				t = netdev_priv(dev);
1365 		} else {
1366 			memset(&p, 0, sizeof(p));
1367 		}
1368 		ip6_tnl_parm_to_user(&p, &t->parms);
1369 		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) {
1370 			err = -EFAULT;
1371 		}
1372 		break;
1373 	case SIOCADDTUNNEL:
1374 	case SIOCCHGTUNNEL:
1375 		err = -EPERM;
1376 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1377 			break;
1378 		err = -EFAULT;
1379 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1380 			break;
1381 		err = -EINVAL;
1382 		if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP &&
1383 		    p.proto != 0)
1384 			break;
1385 		ip6_tnl_parm_from_user(&p1, &p);
1386 		t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
1387 		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
1388 			if (t != NULL) {
1389 				if (t->dev != dev) {
1390 					err = -EEXIST;
1391 					break;
1392 				}
1393 			} else
1394 				t = netdev_priv(dev);
1395 
1396 			err = ip6_tnl_update(t, &p1);
1397 		}
1398 		if (t) {
1399 			err = 0;
1400 			ip6_tnl_parm_to_user(&p, &t->parms);
1401 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1402 				err = -EFAULT;
1403 
1404 		} else
1405 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1406 		break;
1407 	case SIOCDELTUNNEL:
1408 		err = -EPERM;
1409 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1410 			break;
1411 
1412 		if (dev == ip6n->fb_tnl_dev) {
1413 			err = -EFAULT;
1414 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1415 				break;
1416 			err = -ENOENT;
1417 			ip6_tnl_parm_from_user(&p1, &p);
1418 			t = ip6_tnl_locate(net, &p1, 0);
1419 			if (t == NULL)
1420 				break;
1421 			err = -EPERM;
1422 			if (t->dev == ip6n->fb_tnl_dev)
1423 				break;
1424 			dev = t->dev;
1425 		}
1426 		err = 0;
1427 		unregister_netdevice(dev);
1428 		break;
1429 	default:
1430 		err = -EINVAL;
1431 	}
1432 	return err;
1433 }
1434 
1435 /**
1436  * ip6_tnl_change_mtu - change mtu manually for tunnel device
1437  *   @dev: virtual device associated with tunnel
1438  *   @new_mtu: the new mtu
1439  *
1440  * Return:
1441  *   0 on success,
1442  *   %-EINVAL if mtu too small
1443  **/
1444 
1445 static int
1446 ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
1447 {
1448 	struct ip6_tnl *tnl = netdev_priv(dev);
1449 
1450 	if (tnl->parms.proto == IPPROTO_IPIP) {
1451 		if (new_mtu < 68)
1452 			return -EINVAL;
1453 	} else {
1454 		if (new_mtu < IPV6_MIN_MTU)
1455 			return -EINVAL;
1456 	}
1457 	if (new_mtu > 0xFFF8 - dev->hard_header_len)
1458 		return -EINVAL;
1459 	dev->mtu = new_mtu;
1460 	return 0;
1461 }
1462 
1463 
1464 static const struct net_device_ops ip6_tnl_netdev_ops = {
1465 	.ndo_uninit	= ip6_tnl_dev_uninit,
1466 	.ndo_start_xmit = ip6_tnl_xmit,
1467 	.ndo_do_ioctl	= ip6_tnl_ioctl,
1468 	.ndo_change_mtu = ip6_tnl_change_mtu,
1469 	.ndo_get_stats	= ip6_get_stats,
1470 };
1471 
1472 
1473 /**
1474  * ip6_tnl_dev_setup - setup virtual tunnel device
1475  *   @dev: virtual device associated with tunnel
1476  *
1477  * Description:
1478  *   Initialize function pointers and device parameters
1479  **/
1480 
1481 static void ip6_tnl_dev_setup(struct net_device *dev)
1482 {
1483 	struct ip6_tnl *t;
1484 
1485 	dev->netdev_ops = &ip6_tnl_netdev_ops;
1486 	dev->destructor = ip6_dev_free;
1487 
1488 	dev->type = ARPHRD_TUNNEL6;
1489 	dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr);
1490 	dev->mtu = ETH_DATA_LEN - sizeof(struct ipv6hdr);
1491 	t = netdev_priv(dev);
1492 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1493 		dev->mtu -= 8;
1494 	dev->flags |= IFF_NOARP;
1495 	dev->addr_len = sizeof(struct in6_addr);
1496 	netif_keep_dst(dev);
1497 	/* This perm addr will be used as interface identifier by IPv6 */
1498 	dev->addr_assign_type = NET_ADDR_RANDOM;
1499 	eth_random_addr(dev->perm_addr);
1500 }
1501 
1502 
1503 /**
1504  * ip6_tnl_dev_init_gen - general initializer for all tunnel devices
1505  *   @dev: virtual device associated with tunnel
1506  **/
1507 
1508 static inline int
1509 ip6_tnl_dev_init_gen(struct net_device *dev)
1510 {
1511 	struct ip6_tnl *t = netdev_priv(dev);
1512 
1513 	t->dev = dev;
1514 	t->net = dev_net(dev);
1515 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1516 	if (!dev->tstats)
1517 		return -ENOMEM;
1518 	return 0;
1519 }
1520 
1521 /**
1522  * ip6_tnl_dev_init - initializer for all non fallback tunnel devices
1523  *   @dev: virtual device associated with tunnel
1524  **/
1525 
1526 static int ip6_tnl_dev_init(struct net_device *dev)
1527 {
1528 	struct ip6_tnl *t = netdev_priv(dev);
1529 	int err = ip6_tnl_dev_init_gen(dev);
1530 
1531 	if (err)
1532 		return err;
1533 	ip6_tnl_link_config(t);
1534 	return 0;
1535 }
1536 
1537 /**
1538  * ip6_fb_tnl_dev_init - initializer for fallback tunnel device
1539  *   @dev: fallback device
1540  *
1541  * Return: 0
1542  **/
1543 
1544 static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
1545 {
1546 	struct ip6_tnl *t = netdev_priv(dev);
1547 	struct net *net = dev_net(dev);
1548 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1549 	int err = ip6_tnl_dev_init_gen(dev);
1550 
1551 	if (err)
1552 		return err;
1553 
1554 	t->parms.proto = IPPROTO_IPV6;
1555 	dev_hold(dev);
1556 
1557 	ip6_tnl_link_config(t);
1558 
1559 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
1560 	return 0;
1561 }
1562 
1563 static int ip6_tnl_validate(struct nlattr *tb[], struct nlattr *data[])
1564 {
1565 	u8 proto;
1566 
1567 	if (!data || !data[IFLA_IPTUN_PROTO])
1568 		return 0;
1569 
1570 	proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1571 	if (proto != IPPROTO_IPV6 &&
1572 	    proto != IPPROTO_IPIP &&
1573 	    proto != 0)
1574 		return -EINVAL;
1575 
1576 	return 0;
1577 }
1578 
1579 static void ip6_tnl_netlink_parms(struct nlattr *data[],
1580 				  struct __ip6_tnl_parm *parms)
1581 {
1582 	memset(parms, 0, sizeof(*parms));
1583 
1584 	if (!data)
1585 		return;
1586 
1587 	if (data[IFLA_IPTUN_LINK])
1588 		parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1589 
1590 	if (data[IFLA_IPTUN_LOCAL])
1591 		nla_memcpy(&parms->laddr, data[IFLA_IPTUN_LOCAL],
1592 			   sizeof(struct in6_addr));
1593 
1594 	if (data[IFLA_IPTUN_REMOTE])
1595 		nla_memcpy(&parms->raddr, data[IFLA_IPTUN_REMOTE],
1596 			   sizeof(struct in6_addr));
1597 
1598 	if (data[IFLA_IPTUN_TTL])
1599 		parms->hop_limit = nla_get_u8(data[IFLA_IPTUN_TTL]);
1600 
1601 	if (data[IFLA_IPTUN_ENCAP_LIMIT])
1602 		parms->encap_limit = nla_get_u8(data[IFLA_IPTUN_ENCAP_LIMIT]);
1603 
1604 	if (data[IFLA_IPTUN_FLOWINFO])
1605 		parms->flowinfo = nla_get_be32(data[IFLA_IPTUN_FLOWINFO]);
1606 
1607 	if (data[IFLA_IPTUN_FLAGS])
1608 		parms->flags = nla_get_u32(data[IFLA_IPTUN_FLAGS]);
1609 
1610 	if (data[IFLA_IPTUN_PROTO])
1611 		parms->proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1612 }
1613 
1614 static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
1615 			   struct nlattr *tb[], struct nlattr *data[])
1616 {
1617 	struct net *net = dev_net(dev);
1618 	struct ip6_tnl *nt;
1619 
1620 	nt = netdev_priv(dev);
1621 	ip6_tnl_netlink_parms(data, &nt->parms);
1622 
1623 	if (ip6_tnl_locate(net, &nt->parms, 0))
1624 		return -EEXIST;
1625 
1626 	return ip6_tnl_create2(dev);
1627 }
1628 
1629 static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[],
1630 			      struct nlattr *data[])
1631 {
1632 	struct ip6_tnl *t = netdev_priv(dev);
1633 	struct __ip6_tnl_parm p;
1634 	struct net *net = t->net;
1635 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1636 
1637 	if (dev == ip6n->fb_tnl_dev)
1638 		return -EINVAL;
1639 
1640 	ip6_tnl_netlink_parms(data, &p);
1641 
1642 	t = ip6_tnl_locate(net, &p, 0);
1643 
1644 	if (t) {
1645 		if (t->dev != dev)
1646 			return -EEXIST;
1647 	} else
1648 		t = netdev_priv(dev);
1649 
1650 	return ip6_tnl_update(t, &p);
1651 }
1652 
1653 static void ip6_tnl_dellink(struct net_device *dev, struct list_head *head)
1654 {
1655 	struct net *net = dev_net(dev);
1656 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1657 
1658 	if (dev != ip6n->fb_tnl_dev)
1659 		unregister_netdevice_queue(dev, head);
1660 }
1661 
1662 static size_t ip6_tnl_get_size(const struct net_device *dev)
1663 {
1664 	return
1665 		/* IFLA_IPTUN_LINK */
1666 		nla_total_size(4) +
1667 		/* IFLA_IPTUN_LOCAL */
1668 		nla_total_size(sizeof(struct in6_addr)) +
1669 		/* IFLA_IPTUN_REMOTE */
1670 		nla_total_size(sizeof(struct in6_addr)) +
1671 		/* IFLA_IPTUN_TTL */
1672 		nla_total_size(1) +
1673 		/* IFLA_IPTUN_ENCAP_LIMIT */
1674 		nla_total_size(1) +
1675 		/* IFLA_IPTUN_FLOWINFO */
1676 		nla_total_size(4) +
1677 		/* IFLA_IPTUN_FLAGS */
1678 		nla_total_size(4) +
1679 		/* IFLA_IPTUN_PROTO */
1680 		nla_total_size(1) +
1681 		0;
1682 }
1683 
1684 static int ip6_tnl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1685 {
1686 	struct ip6_tnl *tunnel = netdev_priv(dev);
1687 	struct __ip6_tnl_parm *parm = &tunnel->parms;
1688 
1689 	if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1690 	    nla_put(skb, IFLA_IPTUN_LOCAL, sizeof(struct in6_addr),
1691 		    &parm->laddr) ||
1692 	    nla_put(skb, IFLA_IPTUN_REMOTE, sizeof(struct in6_addr),
1693 		    &parm->raddr) ||
1694 	    nla_put_u8(skb, IFLA_IPTUN_TTL, parm->hop_limit) ||
1695 	    nla_put_u8(skb, IFLA_IPTUN_ENCAP_LIMIT, parm->encap_limit) ||
1696 	    nla_put_be32(skb, IFLA_IPTUN_FLOWINFO, parm->flowinfo) ||
1697 	    nla_put_u32(skb, IFLA_IPTUN_FLAGS, parm->flags) ||
1698 	    nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto))
1699 		goto nla_put_failure;
1700 	return 0;
1701 
1702 nla_put_failure:
1703 	return -EMSGSIZE;
1704 }
1705 
1706 static const struct nla_policy ip6_tnl_policy[IFLA_IPTUN_MAX + 1] = {
1707 	[IFLA_IPTUN_LINK]		= { .type = NLA_U32 },
1708 	[IFLA_IPTUN_LOCAL]		= { .len = sizeof(struct in6_addr) },
1709 	[IFLA_IPTUN_REMOTE]		= { .len = sizeof(struct in6_addr) },
1710 	[IFLA_IPTUN_TTL]		= { .type = NLA_U8 },
1711 	[IFLA_IPTUN_ENCAP_LIMIT]	= { .type = NLA_U8 },
1712 	[IFLA_IPTUN_FLOWINFO]		= { .type = NLA_U32 },
1713 	[IFLA_IPTUN_FLAGS]		= { .type = NLA_U32 },
1714 	[IFLA_IPTUN_PROTO]		= { .type = NLA_U8 },
1715 };
1716 
1717 static struct rtnl_link_ops ip6_link_ops __read_mostly = {
1718 	.kind		= "ip6tnl",
1719 	.maxtype	= IFLA_IPTUN_MAX,
1720 	.policy		= ip6_tnl_policy,
1721 	.priv_size	= sizeof(struct ip6_tnl),
1722 	.setup		= ip6_tnl_dev_setup,
1723 	.validate	= ip6_tnl_validate,
1724 	.newlink	= ip6_tnl_newlink,
1725 	.changelink	= ip6_tnl_changelink,
1726 	.dellink	= ip6_tnl_dellink,
1727 	.get_size	= ip6_tnl_get_size,
1728 	.fill_info	= ip6_tnl_fill_info,
1729 };
1730 
1731 static struct xfrm6_tunnel ip4ip6_handler __read_mostly = {
1732 	.handler	= ip4ip6_rcv,
1733 	.err_handler	= ip4ip6_err,
1734 	.priority	=	1,
1735 };
1736 
1737 static struct xfrm6_tunnel ip6ip6_handler __read_mostly = {
1738 	.handler	= ip6ip6_rcv,
1739 	.err_handler	= ip6ip6_err,
1740 	.priority	=	1,
1741 };
1742 
1743 static void __net_exit ip6_tnl_destroy_tunnels(struct net *net)
1744 {
1745 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1746 	struct net_device *dev, *aux;
1747 	int h;
1748 	struct ip6_tnl *t;
1749 	LIST_HEAD(list);
1750 
1751 	for_each_netdev_safe(net, dev, aux)
1752 		if (dev->rtnl_link_ops == &ip6_link_ops)
1753 			unregister_netdevice_queue(dev, &list);
1754 
1755 	for (h = 0; h < HASH_SIZE; h++) {
1756 		t = rtnl_dereference(ip6n->tnls_r_l[h]);
1757 		while (t != NULL) {
1758 			/* If dev is in the same netns, it has already
1759 			 * been added to the list by the previous loop.
1760 			 */
1761 			if (!net_eq(dev_net(t->dev), net))
1762 				unregister_netdevice_queue(t->dev, &list);
1763 			t = rtnl_dereference(t->next);
1764 		}
1765 	}
1766 
1767 	unregister_netdevice_many(&list);
1768 }
1769 
1770 static int __net_init ip6_tnl_init_net(struct net *net)
1771 {
1772 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1773 	struct ip6_tnl *t = NULL;
1774 	int err;
1775 
1776 	ip6n->tnls[0] = ip6n->tnls_wc;
1777 	ip6n->tnls[1] = ip6n->tnls_r_l;
1778 
1779 	err = -ENOMEM;
1780 	ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
1781 					NET_NAME_UNKNOWN, ip6_tnl_dev_setup);
1782 
1783 	if (!ip6n->fb_tnl_dev)
1784 		goto err_alloc_dev;
1785 	dev_net_set(ip6n->fb_tnl_dev, net);
1786 	ip6n->fb_tnl_dev->rtnl_link_ops = &ip6_link_ops;
1787 	/* FB netdevice is special: we have one, and only one per netns.
1788 	 * Allowing to move it to another netns is clearly unsafe.
1789 	 */
1790 	ip6n->fb_tnl_dev->features |= NETIF_F_NETNS_LOCAL;
1791 
1792 	err = ip6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
1793 	if (err < 0)
1794 		goto err_register;
1795 
1796 	err = register_netdev(ip6n->fb_tnl_dev);
1797 	if (err < 0)
1798 		goto err_register;
1799 
1800 	t = netdev_priv(ip6n->fb_tnl_dev);
1801 
1802 	strcpy(t->parms.name, ip6n->fb_tnl_dev->name);
1803 	return 0;
1804 
1805 err_register:
1806 	ip6_dev_free(ip6n->fb_tnl_dev);
1807 err_alloc_dev:
1808 	return err;
1809 }
1810 
1811 static void __net_exit ip6_tnl_exit_net(struct net *net)
1812 {
1813 	rtnl_lock();
1814 	ip6_tnl_destroy_tunnels(net);
1815 	rtnl_unlock();
1816 }
1817 
1818 static struct pernet_operations ip6_tnl_net_ops = {
1819 	.init = ip6_tnl_init_net,
1820 	.exit = ip6_tnl_exit_net,
1821 	.id   = &ip6_tnl_net_id,
1822 	.size = sizeof(struct ip6_tnl_net),
1823 };
1824 
1825 /**
1826  * ip6_tunnel_init - register protocol and reserve needed resources
1827  *
1828  * Return: 0 on success
1829  **/
1830 
1831 static int __init ip6_tunnel_init(void)
1832 {
1833 	int  err;
1834 
1835 	err = register_pernet_device(&ip6_tnl_net_ops);
1836 	if (err < 0)
1837 		goto out_pernet;
1838 
1839 	err = xfrm6_tunnel_register(&ip4ip6_handler, AF_INET);
1840 	if (err < 0) {
1841 		pr_err("%s: can't register ip4ip6\n", __func__);
1842 		goto out_ip4ip6;
1843 	}
1844 
1845 	err = xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6);
1846 	if (err < 0) {
1847 		pr_err("%s: can't register ip6ip6\n", __func__);
1848 		goto out_ip6ip6;
1849 	}
1850 	err = rtnl_link_register(&ip6_link_ops);
1851 	if (err < 0)
1852 		goto rtnl_link_failed;
1853 
1854 	return 0;
1855 
1856 rtnl_link_failed:
1857 	xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6);
1858 out_ip6ip6:
1859 	xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
1860 out_ip4ip6:
1861 	unregister_pernet_device(&ip6_tnl_net_ops);
1862 out_pernet:
1863 	return err;
1864 }
1865 
1866 /**
1867  * ip6_tunnel_cleanup - free resources and unregister protocol
1868  **/
1869 
1870 static void __exit ip6_tunnel_cleanup(void)
1871 {
1872 	rtnl_link_unregister(&ip6_link_ops);
1873 	if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))
1874 		pr_info("%s: can't deregister ip4ip6\n", __func__);
1875 
1876 	if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))
1877 		pr_info("%s: can't deregister ip6ip6\n", __func__);
1878 
1879 	unregister_pernet_device(&ip6_tnl_net_ops);
1880 }
1881 
1882 module_init(ip6_tunnel_init);
1883 module_exit(ip6_tunnel_cleanup);
1884