xref: /openbmc/linux/net/ipv6/ip6_vti.c (revision d9f6e12f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	IPv6 virtual tunneling interface
4  *
5  *	Copyright (C) 2013 secunet Security Networks AG
6  *
7  *	Author:
8  *	Steffen Klassert <steffen.klassert@secunet.com>
9  *
10  *	Based on:
11  *	net/ipv6/ip6_tunnel.c
12  */
13 
14 #include <linux/module.h>
15 #include <linux/capability.h>
16 #include <linux/errno.h>
17 #include <linux/types.h>
18 #include <linux/sockios.h>
19 #include <linux/icmp.h>
20 #include <linux/if.h>
21 #include <linux/in.h>
22 #include <linux/ip.h>
23 #include <linux/net.h>
24 #include <linux/in6.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/icmpv6.h>
28 #include <linux/init.h>
29 #include <linux/route.h>
30 #include <linux/rtnetlink.h>
31 #include <linux/netfilter_ipv6.h>
32 #include <linux/slab.h>
33 #include <linux/hash.h>
34 
35 #include <linux/uaccess.h>
36 #include <linux/atomic.h>
37 
38 #include <net/icmp.h>
39 #include <net/ip.h>
40 #include <net/ip_tunnels.h>
41 #include <net/ipv6.h>
42 #include <net/ip6_route.h>
43 #include <net/addrconf.h>
44 #include <net/ip6_tunnel.h>
45 #include <net/xfrm.h>
46 #include <net/net_namespace.h>
47 #include <net/netns/generic.h>
48 #include <linux/etherdevice.h>
49 
50 #define IP6_VTI_HASH_SIZE_SHIFT  5
51 #define IP6_VTI_HASH_SIZE (1 << IP6_VTI_HASH_SIZE_SHIFT)
52 
53 static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
54 {
55 	u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
56 
57 	return hash_32(hash, IP6_VTI_HASH_SIZE_SHIFT);
58 }
59 
60 static int vti6_dev_init(struct net_device *dev);
61 static void vti6_dev_setup(struct net_device *dev);
62 static struct rtnl_link_ops vti6_link_ops __read_mostly;
63 
64 static unsigned int vti6_net_id __read_mostly;
65 struct vti6_net {
66 	/* the vti6 tunnel fallback device */
67 	struct net_device *fb_tnl_dev;
68 	/* lists for storing tunnels in use */
69 	struct ip6_tnl __rcu *tnls_r_l[IP6_VTI_HASH_SIZE];
70 	struct ip6_tnl __rcu *tnls_wc[1];
71 	struct ip6_tnl __rcu **tnls[2];
72 };
73 
74 #define for_each_vti6_tunnel_rcu(start) \
75 	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
76 
77 /**
78  * vti6_tnl_lookup - fetch tunnel matching the end-point addresses
79  *   @net: network namespace
80  *   @remote: the address of the tunnel exit-point
81  *   @local: the address of the tunnel entry-point
82  *
83  * Return:
84  *   tunnel matching given end-points if found,
85  *   else fallback tunnel if its device is up,
86  *   else %NULL
87  **/
88 static struct ip6_tnl *
89 vti6_tnl_lookup(struct net *net, const struct in6_addr *remote,
90 		const struct in6_addr *local)
91 {
92 	unsigned int hash = HASH(remote, local);
93 	struct ip6_tnl *t;
94 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
95 	struct in6_addr any;
96 
97 	for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
98 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
99 		    ipv6_addr_equal(remote, &t->parms.raddr) &&
100 		    (t->dev->flags & IFF_UP))
101 			return t;
102 	}
103 
104 	memset(&any, 0, sizeof(any));
105 	hash = HASH(&any, local);
106 	for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
107 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
108 		    (t->dev->flags & IFF_UP))
109 			return t;
110 	}
111 
112 	hash = HASH(remote, &any);
113 	for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
114 		if (ipv6_addr_equal(remote, &t->parms.raddr) &&
115 		    (t->dev->flags & IFF_UP))
116 			return t;
117 	}
118 
119 	t = rcu_dereference(ip6n->tnls_wc[0]);
120 	if (t && (t->dev->flags & IFF_UP))
121 		return t;
122 
123 	return NULL;
124 }
125 
126 /**
127  * vti6_tnl_bucket - get head of list matching given tunnel parameters
128  *   @ip6n: the private data for ip6_vti in the netns
129  *   @p: parameters containing tunnel end-points
130  *
131  * Description:
132  *   vti6_tnl_bucket() returns the head of the list matching the
133  *   &struct in6_addr entries laddr and raddr in @p.
134  *
135  * Return: head of IPv6 tunnel list
136  **/
137 static struct ip6_tnl __rcu **
138 vti6_tnl_bucket(struct vti6_net *ip6n, const struct __ip6_tnl_parm *p)
139 {
140 	const struct in6_addr *remote = &p->raddr;
141 	const struct in6_addr *local = &p->laddr;
142 	unsigned int h = 0;
143 	int prio = 0;
144 
145 	if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
146 		prio = 1;
147 		h = HASH(remote, local);
148 	}
149 	return &ip6n->tnls[prio][h];
150 }
151 
152 static void
153 vti6_tnl_link(struct vti6_net *ip6n, struct ip6_tnl *t)
154 {
155 	struct ip6_tnl __rcu **tp = vti6_tnl_bucket(ip6n, &t->parms);
156 
157 	rcu_assign_pointer(t->next , rtnl_dereference(*tp));
158 	rcu_assign_pointer(*tp, t);
159 }
160 
161 static void
162 vti6_tnl_unlink(struct vti6_net *ip6n, struct ip6_tnl *t)
163 {
164 	struct ip6_tnl __rcu **tp;
165 	struct ip6_tnl *iter;
166 
167 	for (tp = vti6_tnl_bucket(ip6n, &t->parms);
168 	     (iter = rtnl_dereference(*tp)) != NULL;
169 	     tp = &iter->next) {
170 		if (t == iter) {
171 			rcu_assign_pointer(*tp, t->next);
172 			break;
173 		}
174 	}
175 }
176 
177 static void vti6_dev_free(struct net_device *dev)
178 {
179 	free_percpu(dev->tstats);
180 }
181 
182 static int vti6_tnl_create2(struct net_device *dev)
183 {
184 	struct ip6_tnl *t = netdev_priv(dev);
185 	struct net *net = dev_net(dev);
186 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
187 	int err;
188 
189 	dev->rtnl_link_ops = &vti6_link_ops;
190 	err = register_netdevice(dev);
191 	if (err < 0)
192 		goto out;
193 
194 	strcpy(t->parms.name, dev->name);
195 
196 	dev_hold(dev);
197 	vti6_tnl_link(ip6n, t);
198 
199 	return 0;
200 
201 out:
202 	return err;
203 }
204 
205 static struct ip6_tnl *vti6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
206 {
207 	struct net_device *dev;
208 	struct ip6_tnl *t;
209 	char name[IFNAMSIZ];
210 	int err;
211 
212 	if (p->name[0]) {
213 		if (!dev_valid_name(p->name))
214 			goto failed;
215 		strlcpy(name, p->name, IFNAMSIZ);
216 	} else {
217 		sprintf(name, "ip6_vti%%d");
218 	}
219 
220 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, vti6_dev_setup);
221 	if (!dev)
222 		goto failed;
223 
224 	dev_net_set(dev, net);
225 
226 	t = netdev_priv(dev);
227 	t->parms = *p;
228 	t->net = dev_net(dev);
229 
230 	err = vti6_tnl_create2(dev);
231 	if (err < 0)
232 		goto failed_free;
233 
234 	return t;
235 
236 failed_free:
237 	free_netdev(dev);
238 failed:
239 	return NULL;
240 }
241 
242 /**
243  * vti6_locate - find or create tunnel matching given parameters
244  *   @net: network namespace
245  *   @p: tunnel parameters
246  *   @create: != 0 if allowed to create new tunnel if no match found
247  *
248  * Description:
249  *   vti6_locate() first tries to locate an existing tunnel
250  *   based on @parms. If this is unsuccessful, but @create is set a new
251  *   tunnel device is created and registered for use.
252  *
253  * Return:
254  *   matching tunnel or NULL
255  **/
256 static struct ip6_tnl *vti6_locate(struct net *net, struct __ip6_tnl_parm *p,
257 				   int create)
258 {
259 	const struct in6_addr *remote = &p->raddr;
260 	const struct in6_addr *local = &p->laddr;
261 	struct ip6_tnl __rcu **tp;
262 	struct ip6_tnl *t;
263 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
264 
265 	for (tp = vti6_tnl_bucket(ip6n, p);
266 	     (t = rtnl_dereference(*tp)) != NULL;
267 	     tp = &t->next) {
268 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
269 		    ipv6_addr_equal(remote, &t->parms.raddr)) {
270 			if (create)
271 				return NULL;
272 
273 			return t;
274 		}
275 	}
276 	if (!create)
277 		return NULL;
278 	return vti6_tnl_create(net, p);
279 }
280 
281 /**
282  * vti6_dev_uninit - tunnel device uninitializer
283  *   @dev: the device to be destroyed
284  *
285  * Description:
286  *   vti6_dev_uninit() removes tunnel from its list
287  **/
288 static void vti6_dev_uninit(struct net_device *dev)
289 {
290 	struct ip6_tnl *t = netdev_priv(dev);
291 	struct vti6_net *ip6n = net_generic(t->net, vti6_net_id);
292 
293 	if (dev == ip6n->fb_tnl_dev)
294 		RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
295 	else
296 		vti6_tnl_unlink(ip6n, t);
297 	dev_put(dev);
298 }
299 
300 static int vti6_input_proto(struct sk_buff *skb, int nexthdr, __be32 spi,
301 			    int encap_type)
302 {
303 	struct ip6_tnl *t;
304 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
305 
306 	rcu_read_lock();
307 	t = vti6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
308 	if (t) {
309 		if (t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) {
310 			rcu_read_unlock();
311 			goto discard;
312 		}
313 
314 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
315 			rcu_read_unlock();
316 			goto discard;
317 		}
318 
319 		ipv6h = ipv6_hdr(skb);
320 		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
321 			t->dev->stats.rx_dropped++;
322 			rcu_read_unlock();
323 			goto discard;
324 		}
325 
326 		rcu_read_unlock();
327 
328 		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
329 		XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
330 		XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
331 		return xfrm_input(skb, nexthdr, spi, encap_type);
332 	}
333 	rcu_read_unlock();
334 	return -EINVAL;
335 discard:
336 	kfree_skb(skb);
337 	return 0;
338 }
339 
340 static int vti6_rcv(struct sk_buff *skb)
341 {
342 	int nexthdr = skb_network_header(skb)[IP6CB(skb)->nhoff];
343 
344 	return vti6_input_proto(skb, nexthdr, 0, 0);
345 }
346 
347 static int vti6_rcv_cb(struct sk_buff *skb, int err)
348 {
349 	unsigned short family;
350 	struct net_device *dev;
351 	struct xfrm_state *x;
352 	const struct xfrm_mode *inner_mode;
353 	struct ip6_tnl *t = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6;
354 	u32 orig_mark = skb->mark;
355 	int ret;
356 
357 	if (!t)
358 		return 1;
359 
360 	dev = t->dev;
361 
362 	if (err) {
363 		dev->stats.rx_errors++;
364 		dev->stats.rx_dropped++;
365 
366 		return 0;
367 	}
368 
369 	x = xfrm_input_state(skb);
370 
371 	inner_mode = &x->inner_mode;
372 
373 	if (x->sel.family == AF_UNSPEC) {
374 		inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
375 		if (inner_mode == NULL) {
376 			XFRM_INC_STATS(dev_net(skb->dev),
377 				       LINUX_MIB_XFRMINSTATEMODEERROR);
378 			return -EINVAL;
379 		}
380 	}
381 
382 	family = inner_mode->family;
383 
384 	skb->mark = be32_to_cpu(t->parms.i_key);
385 	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
386 	skb->mark = orig_mark;
387 
388 	if (!ret)
389 		return -EPERM;
390 
391 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(skb->dev)));
392 	skb->dev = dev;
393 	dev_sw_netstats_rx_add(dev, skb->len);
394 
395 	return 0;
396 }
397 
398 /**
399  * vti6_addr_conflict - compare packet addresses to tunnel's own
400  *   @t: the outgoing tunnel device
401  *   @hdr: IPv6 header from the incoming packet
402  *
403  * Description:
404  *   Avoid trivial tunneling loop by checking that tunnel exit-point
405  *   doesn't match source of incoming packet.
406  *
407  * Return:
408  *   1 if conflict,
409  *   0 else
410  **/
411 static inline bool
412 vti6_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
413 {
414 	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
415 }
416 
417 static bool vti6_state_check(const struct xfrm_state *x,
418 			     const struct in6_addr *dst,
419 			     const struct in6_addr *src)
420 {
421 	xfrm_address_t *daddr = (xfrm_address_t *)dst;
422 	xfrm_address_t *saddr = (xfrm_address_t *)src;
423 
424 	/* if there is no transform then this tunnel is not functional.
425 	 * Or if the xfrm is not mode tunnel.
426 	 */
427 	if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
428 	    x->props.family != AF_INET6)
429 		return false;
430 
431 	if (ipv6_addr_any(dst))
432 		return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET6);
433 
434 	if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET6))
435 		return false;
436 
437 	return true;
438 }
439 
440 /**
441  * vti6_xmit - send a packet
442  *   @skb: the outgoing socket buffer
443  *   @dev: the outgoing tunnel device
444  *   @fl: the flow informations for the xfrm_lookup
445  **/
446 static int
447 vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
448 {
449 	struct ip6_tnl *t = netdev_priv(dev);
450 	struct net_device_stats *stats = &t->dev->stats;
451 	struct dst_entry *dst = skb_dst(skb);
452 	struct net_device *tdev;
453 	struct xfrm_state *x;
454 	int pkt_len = skb->len;
455 	int err = -1;
456 	int mtu;
457 
458 	if (!dst) {
459 		switch (skb->protocol) {
460 		case htons(ETH_P_IP): {
461 			struct rtable *rt;
462 
463 			fl->u.ip4.flowi4_oif = dev->ifindex;
464 			fl->u.ip4.flowi4_flags |= FLOWI_FLAG_ANYSRC;
465 			rt = __ip_route_output_key(dev_net(dev), &fl->u.ip4);
466 			if (IS_ERR(rt))
467 				goto tx_err_link_failure;
468 			dst = &rt->dst;
469 			skb_dst_set(skb, dst);
470 			break;
471 		}
472 		case htons(ETH_P_IPV6):
473 			fl->u.ip6.flowi6_oif = dev->ifindex;
474 			fl->u.ip6.flowi6_flags |= FLOWI_FLAG_ANYSRC;
475 			dst = ip6_route_output(dev_net(dev), NULL, &fl->u.ip6);
476 			if (dst->error) {
477 				dst_release(dst);
478 				dst = NULL;
479 				goto tx_err_link_failure;
480 			}
481 			skb_dst_set(skb, dst);
482 			break;
483 		default:
484 			goto tx_err_link_failure;
485 		}
486 	}
487 
488 	dst_hold(dst);
489 	dst = xfrm_lookup_route(t->net, dst, fl, NULL, 0);
490 	if (IS_ERR(dst)) {
491 		err = PTR_ERR(dst);
492 		dst = NULL;
493 		goto tx_err_link_failure;
494 	}
495 
496 	if (dst->flags & DST_XFRM_QUEUE)
497 		goto queued;
498 
499 	x = dst->xfrm;
500 	if (!vti6_state_check(x, &t->parms.raddr, &t->parms.laddr))
501 		goto tx_err_link_failure;
502 
503 	if (!ip6_tnl_xmit_ctl(t, (const struct in6_addr *)&x->props.saddr,
504 			      (const struct in6_addr *)&x->id.daddr))
505 		goto tx_err_link_failure;
506 
507 	tdev = dst->dev;
508 
509 	if (tdev == dev) {
510 		stats->collisions++;
511 		net_warn_ratelimited("%s: Local routing loop detected!\n",
512 				     t->parms.name);
513 		goto tx_err_dst_release;
514 	}
515 
516 	mtu = dst_mtu(dst);
517 	if (skb->len > mtu) {
518 		skb_dst_update_pmtu_no_confirm(skb, mtu);
519 
520 		if (skb->protocol == htons(ETH_P_IPV6)) {
521 			if (mtu < IPV6_MIN_MTU)
522 				mtu = IPV6_MIN_MTU;
523 
524 			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
525 		} else {
526 			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
527 				      htonl(mtu));
528 		}
529 
530 		err = -EMSGSIZE;
531 		goto tx_err_dst_release;
532 	}
533 
534 queued:
535 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
536 	skb_dst_set(skb, dst);
537 	skb->dev = skb_dst(skb)->dev;
538 
539 	err = dst_output(t->net, skb->sk, skb);
540 	if (net_xmit_eval(err) == 0)
541 		err = pkt_len;
542 	iptunnel_xmit_stats(dev, err);
543 
544 	return 0;
545 tx_err_link_failure:
546 	stats->tx_carrier_errors++;
547 	dst_link_failure(skb);
548 tx_err_dst_release:
549 	dst_release(dst);
550 	return err;
551 }
552 
553 static netdev_tx_t
554 vti6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
555 {
556 	struct ip6_tnl *t = netdev_priv(dev);
557 	struct net_device_stats *stats = &t->dev->stats;
558 	struct flowi fl;
559 	int ret;
560 
561 	if (!pskb_inet_may_pull(skb))
562 		goto tx_err;
563 
564 	memset(&fl, 0, sizeof(fl));
565 
566 	switch (skb->protocol) {
567 	case htons(ETH_P_IPV6):
568 		if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
569 		    vti6_addr_conflict(t, ipv6_hdr(skb)))
570 			goto tx_err;
571 
572 		xfrm_decode_session(skb, &fl, AF_INET6);
573 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
574 		break;
575 	case htons(ETH_P_IP):
576 		xfrm_decode_session(skb, &fl, AF_INET);
577 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
578 		break;
579 	default:
580 		goto tx_err;
581 	}
582 
583 	/* override mark with tunnel output key */
584 	fl.flowi_mark = be32_to_cpu(t->parms.o_key);
585 
586 	ret = vti6_xmit(skb, dev, &fl);
587 	if (ret < 0)
588 		goto tx_err;
589 
590 	return NETDEV_TX_OK;
591 
592 tx_err:
593 	stats->tx_errors++;
594 	stats->tx_dropped++;
595 	kfree_skb(skb);
596 	return NETDEV_TX_OK;
597 }
598 
599 static int vti6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
600 		    u8 type, u8 code, int offset, __be32 info)
601 {
602 	__be32 spi;
603 	__u32 mark;
604 	struct xfrm_state *x;
605 	struct ip6_tnl *t;
606 	struct ip_esp_hdr *esph;
607 	struct ip_auth_hdr *ah;
608 	struct ip_comp_hdr *ipch;
609 	struct net *net = dev_net(skb->dev);
610 	const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
611 	int protocol = iph->nexthdr;
612 
613 	t = vti6_tnl_lookup(dev_net(skb->dev), &iph->daddr, &iph->saddr);
614 	if (!t)
615 		return -1;
616 
617 	mark = be32_to_cpu(t->parms.o_key);
618 
619 	switch (protocol) {
620 	case IPPROTO_ESP:
621 		esph = (struct ip_esp_hdr *)(skb->data + offset);
622 		spi = esph->spi;
623 		break;
624 	case IPPROTO_AH:
625 		ah = (struct ip_auth_hdr *)(skb->data + offset);
626 		spi = ah->spi;
627 		break;
628 	case IPPROTO_COMP:
629 		ipch = (struct ip_comp_hdr *)(skb->data + offset);
630 		spi = htonl(ntohs(ipch->cpi));
631 		break;
632 	default:
633 		return 0;
634 	}
635 
636 	if (type != ICMPV6_PKT_TOOBIG &&
637 	    type != NDISC_REDIRECT)
638 		return 0;
639 
640 	x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
641 			      spi, protocol, AF_INET6);
642 	if (!x)
643 		return 0;
644 
645 	if (type == NDISC_REDIRECT)
646 		ip6_redirect(skb, net, skb->dev->ifindex, 0,
647 			     sock_net_uid(net, NULL));
648 	else
649 		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
650 	xfrm_state_put(x);
651 
652 	return 0;
653 }
654 
655 static void vti6_link_config(struct ip6_tnl *t, bool keep_mtu)
656 {
657 	struct net_device *dev = t->dev;
658 	struct __ip6_tnl_parm *p = &t->parms;
659 	struct net_device *tdev = NULL;
660 	int mtu;
661 
662 	memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
663 	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
664 
665 	p->flags &= ~(IP6_TNL_F_CAP_XMIT | IP6_TNL_F_CAP_RCV |
666 		      IP6_TNL_F_CAP_PER_PACKET);
667 	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
668 
669 	if (p->flags & IP6_TNL_F_CAP_XMIT && p->flags & IP6_TNL_F_CAP_RCV)
670 		dev->flags |= IFF_POINTOPOINT;
671 	else
672 		dev->flags &= ~IFF_POINTOPOINT;
673 
674 	if (keep_mtu && dev->mtu) {
675 		dev->mtu = clamp(dev->mtu, dev->min_mtu, dev->max_mtu);
676 		return;
677 	}
678 
679 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
680 		int strict = (ipv6_addr_type(&p->raddr) &
681 			      (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
682 		struct rt6_info *rt = rt6_lookup(t->net,
683 						 &p->raddr, &p->laddr,
684 						 p->link, NULL, strict);
685 
686 		if (rt)
687 			tdev = rt->dst.dev;
688 		ip6_rt_put(rt);
689 	}
690 
691 	if (!tdev && p->link)
692 		tdev = __dev_get_by_index(t->net, p->link);
693 
694 	if (tdev)
695 		mtu = tdev->mtu - sizeof(struct ipv6hdr);
696 	else
697 		mtu = ETH_DATA_LEN - LL_MAX_HEADER - sizeof(struct ipv6hdr);
698 
699 	dev->mtu = max_t(int, mtu, IPV4_MIN_MTU);
700 }
701 
702 /**
703  * vti6_tnl_change - update the tunnel parameters
704  *   @t: tunnel to be changed
705  *   @p: tunnel configuration parameters
706  *   @keep_mtu: MTU was set from userspace, don't re-compute it
707  *
708  * Description:
709  *   vti6_tnl_change() updates the tunnel parameters
710  **/
711 static int
712 vti6_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p,
713 		bool keep_mtu)
714 {
715 	t->parms.laddr = p->laddr;
716 	t->parms.raddr = p->raddr;
717 	t->parms.link = p->link;
718 	t->parms.i_key = p->i_key;
719 	t->parms.o_key = p->o_key;
720 	t->parms.proto = p->proto;
721 	t->parms.fwmark = p->fwmark;
722 	dst_cache_reset(&t->dst_cache);
723 	vti6_link_config(t, keep_mtu);
724 	return 0;
725 }
726 
727 static int vti6_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p,
728 		       bool keep_mtu)
729 {
730 	struct net *net = dev_net(t->dev);
731 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
732 	int err;
733 
734 	vti6_tnl_unlink(ip6n, t);
735 	synchronize_net();
736 	err = vti6_tnl_change(t, p, keep_mtu);
737 	vti6_tnl_link(ip6n, t);
738 	netdev_state_change(t->dev);
739 	return err;
740 }
741 
742 static void
743 vti6_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm2 *u)
744 {
745 	p->laddr = u->laddr;
746 	p->raddr = u->raddr;
747 	p->link = u->link;
748 	p->i_key = u->i_key;
749 	p->o_key = u->o_key;
750 	p->proto = u->proto;
751 
752 	memcpy(p->name, u->name, sizeof(u->name));
753 }
754 
755 static void
756 vti6_parm_to_user(struct ip6_tnl_parm2 *u, const struct __ip6_tnl_parm *p)
757 {
758 	u->laddr = p->laddr;
759 	u->raddr = p->raddr;
760 	u->link = p->link;
761 	u->i_key = p->i_key;
762 	u->o_key = p->o_key;
763 	if (u->i_key)
764 		u->i_flags |= GRE_KEY;
765 	if (u->o_key)
766 		u->o_flags |= GRE_KEY;
767 	u->proto = p->proto;
768 
769 	memcpy(u->name, p->name, sizeof(u->name));
770 }
771 
772 /**
773  * vti6_ioctl - configure vti6 tunnels from userspace
774  *   @dev: virtual device associated with tunnel
775  *   @ifr: parameters passed from userspace
776  *   @cmd: command to be performed
777  *
778  * Description:
779  *   vti6_ioctl() is used for managing vti6 tunnels
780  *   from userspace.
781  *
782  *   The possible commands are the following:
783  *     %SIOCGETTUNNEL: get tunnel parameters for device
784  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
785  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
786  *     %SIOCDELTUNNEL: delete tunnel
787  *
788  *   The fallback device "ip6_vti0", created during module
789  *   initialization, can be used for creating other tunnel devices.
790  *
791  * Return:
792  *   0 on success,
793  *   %-EFAULT if unable to copy data to or from userspace,
794  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
795  *   %-EINVAL if passed tunnel parameters are invalid,
796  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
797  *   %-ENODEV if attempting to change or delete a nonexisting device
798  **/
799 static int
800 vti6_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
801 {
802 	int err = 0;
803 	struct ip6_tnl_parm2 p;
804 	struct __ip6_tnl_parm p1;
805 	struct ip6_tnl *t = NULL;
806 	struct net *net = dev_net(dev);
807 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
808 
809 	switch (cmd) {
810 	case SIOCGETTUNNEL:
811 		if (dev == ip6n->fb_tnl_dev) {
812 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
813 				err = -EFAULT;
814 				break;
815 			}
816 			vti6_parm_from_user(&p1, &p);
817 			t = vti6_locate(net, &p1, 0);
818 		} else {
819 			memset(&p, 0, sizeof(p));
820 		}
821 		if (!t)
822 			t = netdev_priv(dev);
823 		vti6_parm_to_user(&p, &t->parms);
824 		if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
825 			err = -EFAULT;
826 		break;
827 	case SIOCADDTUNNEL:
828 	case SIOCCHGTUNNEL:
829 		err = -EPERM;
830 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
831 			break;
832 		err = -EFAULT;
833 		if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
834 			break;
835 		err = -EINVAL;
836 		if (p.proto != IPPROTO_IPV6  && p.proto != 0)
837 			break;
838 		vti6_parm_from_user(&p1, &p);
839 		t = vti6_locate(net, &p1, cmd == SIOCADDTUNNEL);
840 		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
841 			if (t) {
842 				if (t->dev != dev) {
843 					err = -EEXIST;
844 					break;
845 				}
846 			} else
847 				t = netdev_priv(dev);
848 
849 			err = vti6_update(t, &p1, false);
850 		}
851 		if (t) {
852 			err = 0;
853 			vti6_parm_to_user(&p, &t->parms);
854 			if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
855 				err = -EFAULT;
856 
857 		} else
858 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
859 		break;
860 	case SIOCDELTUNNEL:
861 		err = -EPERM;
862 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
863 			break;
864 
865 		if (dev == ip6n->fb_tnl_dev) {
866 			err = -EFAULT;
867 			if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
868 				break;
869 			err = -ENOENT;
870 			vti6_parm_from_user(&p1, &p);
871 			t = vti6_locate(net, &p1, 0);
872 			if (!t)
873 				break;
874 			err = -EPERM;
875 			if (t->dev == ip6n->fb_tnl_dev)
876 				break;
877 			dev = t->dev;
878 		}
879 		err = 0;
880 		unregister_netdevice(dev);
881 		break;
882 	default:
883 		err = -EINVAL;
884 	}
885 	return err;
886 }
887 
888 static const struct net_device_ops vti6_netdev_ops = {
889 	.ndo_init	= vti6_dev_init,
890 	.ndo_uninit	= vti6_dev_uninit,
891 	.ndo_start_xmit = vti6_tnl_xmit,
892 	.ndo_do_ioctl	= vti6_ioctl,
893 	.ndo_get_stats64 = dev_get_tstats64,
894 	.ndo_get_iflink = ip6_tnl_get_iflink,
895 };
896 
897 /**
898  * vti6_dev_setup - setup virtual tunnel device
899  *   @dev: virtual device associated with tunnel
900  *
901  * Description:
902  *   Initialize function pointers and device parameters
903  **/
904 static void vti6_dev_setup(struct net_device *dev)
905 {
906 	dev->netdev_ops = &vti6_netdev_ops;
907 	dev->header_ops = &ip_tunnel_header_ops;
908 	dev->needs_free_netdev = true;
909 	dev->priv_destructor = vti6_dev_free;
910 
911 	dev->type = ARPHRD_TUNNEL6;
912 	dev->min_mtu = IPV4_MIN_MTU;
913 	dev->max_mtu = IP_MAX_MTU - sizeof(struct ipv6hdr);
914 	dev->flags |= IFF_NOARP;
915 	dev->addr_len = sizeof(struct in6_addr);
916 	netif_keep_dst(dev);
917 	/* This perm addr will be used as interface identifier by IPv6 */
918 	dev->addr_assign_type = NET_ADDR_RANDOM;
919 	eth_random_addr(dev->perm_addr);
920 }
921 
922 /**
923  * vti6_dev_init_gen - general initializer for all tunnel devices
924  *   @dev: virtual device associated with tunnel
925  **/
926 static inline int vti6_dev_init_gen(struct net_device *dev)
927 {
928 	struct ip6_tnl *t = netdev_priv(dev);
929 
930 	t->dev = dev;
931 	t->net = dev_net(dev);
932 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
933 	if (!dev->tstats)
934 		return -ENOMEM;
935 	return 0;
936 }
937 
938 /**
939  * vti6_dev_init - initializer for all non fallback tunnel devices
940  *   @dev: virtual device associated with tunnel
941  **/
942 static int vti6_dev_init(struct net_device *dev)
943 {
944 	struct ip6_tnl *t = netdev_priv(dev);
945 	int err = vti6_dev_init_gen(dev);
946 
947 	if (err)
948 		return err;
949 	vti6_link_config(t, true);
950 	return 0;
951 }
952 
953 /**
954  * vti6_fb_tnl_dev_init - initializer for fallback tunnel device
955  *   @dev: fallback device
956  *
957  * Return: 0
958  **/
959 static int __net_init vti6_fb_tnl_dev_init(struct net_device *dev)
960 {
961 	struct ip6_tnl *t = netdev_priv(dev);
962 	struct net *net = dev_net(dev);
963 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
964 
965 	t->parms.proto = IPPROTO_IPV6;
966 	dev_hold(dev);
967 
968 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
969 	return 0;
970 }
971 
972 static int vti6_validate(struct nlattr *tb[], struct nlattr *data[],
973 			 struct netlink_ext_ack *extack)
974 {
975 	return 0;
976 }
977 
978 static void vti6_netlink_parms(struct nlattr *data[],
979 			       struct __ip6_tnl_parm *parms)
980 {
981 	memset(parms, 0, sizeof(*parms));
982 
983 	if (!data)
984 		return;
985 
986 	if (data[IFLA_VTI_LINK])
987 		parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
988 
989 	if (data[IFLA_VTI_LOCAL])
990 		parms->laddr = nla_get_in6_addr(data[IFLA_VTI_LOCAL]);
991 
992 	if (data[IFLA_VTI_REMOTE])
993 		parms->raddr = nla_get_in6_addr(data[IFLA_VTI_REMOTE]);
994 
995 	if (data[IFLA_VTI_IKEY])
996 		parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
997 
998 	if (data[IFLA_VTI_OKEY])
999 		parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
1000 
1001 	if (data[IFLA_VTI_FWMARK])
1002 		parms->fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]);
1003 }
1004 
1005 static int vti6_newlink(struct net *src_net, struct net_device *dev,
1006 			struct nlattr *tb[], struct nlattr *data[],
1007 			struct netlink_ext_ack *extack)
1008 {
1009 	struct net *net = dev_net(dev);
1010 	struct ip6_tnl *nt;
1011 
1012 	nt = netdev_priv(dev);
1013 	vti6_netlink_parms(data, &nt->parms);
1014 
1015 	nt->parms.proto = IPPROTO_IPV6;
1016 
1017 	if (vti6_locate(net, &nt->parms, 0))
1018 		return -EEXIST;
1019 
1020 	return vti6_tnl_create2(dev);
1021 }
1022 
1023 static void vti6_dellink(struct net_device *dev, struct list_head *head)
1024 {
1025 	struct net *net = dev_net(dev);
1026 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
1027 
1028 	if (dev != ip6n->fb_tnl_dev)
1029 		unregister_netdevice_queue(dev, head);
1030 }
1031 
1032 static int vti6_changelink(struct net_device *dev, struct nlattr *tb[],
1033 			   struct nlattr *data[],
1034 			   struct netlink_ext_ack *extack)
1035 {
1036 	struct ip6_tnl *t;
1037 	struct __ip6_tnl_parm p;
1038 	struct net *net = dev_net(dev);
1039 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
1040 
1041 	if (dev == ip6n->fb_tnl_dev)
1042 		return -EINVAL;
1043 
1044 	vti6_netlink_parms(data, &p);
1045 
1046 	t = vti6_locate(net, &p, 0);
1047 
1048 	if (t) {
1049 		if (t->dev != dev)
1050 			return -EEXIST;
1051 	} else
1052 		t = netdev_priv(dev);
1053 
1054 	return vti6_update(t, &p, tb && tb[IFLA_MTU]);
1055 }
1056 
1057 static size_t vti6_get_size(const struct net_device *dev)
1058 {
1059 	return
1060 		/* IFLA_VTI_LINK */
1061 		nla_total_size(4) +
1062 		/* IFLA_VTI_LOCAL */
1063 		nla_total_size(sizeof(struct in6_addr)) +
1064 		/* IFLA_VTI_REMOTE */
1065 		nla_total_size(sizeof(struct in6_addr)) +
1066 		/* IFLA_VTI_IKEY */
1067 		nla_total_size(4) +
1068 		/* IFLA_VTI_OKEY */
1069 		nla_total_size(4) +
1070 		/* IFLA_VTI_FWMARK */
1071 		nla_total_size(4) +
1072 		0;
1073 }
1074 
1075 static int vti6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1076 {
1077 	struct ip6_tnl *tunnel = netdev_priv(dev);
1078 	struct __ip6_tnl_parm *parm = &tunnel->parms;
1079 
1080 	if (nla_put_u32(skb, IFLA_VTI_LINK, parm->link) ||
1081 	    nla_put_in6_addr(skb, IFLA_VTI_LOCAL, &parm->laddr) ||
1082 	    nla_put_in6_addr(skb, IFLA_VTI_REMOTE, &parm->raddr) ||
1083 	    nla_put_be32(skb, IFLA_VTI_IKEY, parm->i_key) ||
1084 	    nla_put_be32(skb, IFLA_VTI_OKEY, parm->o_key) ||
1085 	    nla_put_u32(skb, IFLA_VTI_FWMARK, parm->fwmark))
1086 		goto nla_put_failure;
1087 	return 0;
1088 
1089 nla_put_failure:
1090 	return -EMSGSIZE;
1091 }
1092 
1093 static const struct nla_policy vti6_policy[IFLA_VTI_MAX + 1] = {
1094 	[IFLA_VTI_LINK]		= { .type = NLA_U32 },
1095 	[IFLA_VTI_LOCAL]	= { .len = sizeof(struct in6_addr) },
1096 	[IFLA_VTI_REMOTE]	= { .len = sizeof(struct in6_addr) },
1097 	[IFLA_VTI_IKEY]		= { .type = NLA_U32 },
1098 	[IFLA_VTI_OKEY]		= { .type = NLA_U32 },
1099 	[IFLA_VTI_FWMARK]	= { .type = NLA_U32 },
1100 };
1101 
1102 static struct rtnl_link_ops vti6_link_ops __read_mostly = {
1103 	.kind		= "vti6",
1104 	.maxtype	= IFLA_VTI_MAX,
1105 	.policy		= vti6_policy,
1106 	.priv_size	= sizeof(struct ip6_tnl),
1107 	.setup		= vti6_dev_setup,
1108 	.validate	= vti6_validate,
1109 	.newlink	= vti6_newlink,
1110 	.dellink	= vti6_dellink,
1111 	.changelink	= vti6_changelink,
1112 	.get_size	= vti6_get_size,
1113 	.fill_info	= vti6_fill_info,
1114 	.get_link_net	= ip6_tnl_get_link_net,
1115 };
1116 
1117 static void __net_exit vti6_destroy_tunnels(struct vti6_net *ip6n,
1118 					    struct list_head *list)
1119 {
1120 	int h;
1121 	struct ip6_tnl *t;
1122 
1123 	for (h = 0; h < IP6_VTI_HASH_SIZE; h++) {
1124 		t = rtnl_dereference(ip6n->tnls_r_l[h]);
1125 		while (t) {
1126 			unregister_netdevice_queue(t->dev, list);
1127 			t = rtnl_dereference(t->next);
1128 		}
1129 	}
1130 
1131 	t = rtnl_dereference(ip6n->tnls_wc[0]);
1132 	if (t)
1133 		unregister_netdevice_queue(t->dev, list);
1134 }
1135 
1136 static int __net_init vti6_init_net(struct net *net)
1137 {
1138 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
1139 	struct ip6_tnl *t = NULL;
1140 	int err;
1141 
1142 	ip6n->tnls[0] = ip6n->tnls_wc;
1143 	ip6n->tnls[1] = ip6n->tnls_r_l;
1144 
1145 	if (!net_has_fallback_tunnels(net))
1146 		return 0;
1147 	err = -ENOMEM;
1148 	ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6_vti0",
1149 					NET_NAME_UNKNOWN, vti6_dev_setup);
1150 
1151 	if (!ip6n->fb_tnl_dev)
1152 		goto err_alloc_dev;
1153 	dev_net_set(ip6n->fb_tnl_dev, net);
1154 	ip6n->fb_tnl_dev->rtnl_link_ops = &vti6_link_ops;
1155 
1156 	err = vti6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
1157 	if (err < 0)
1158 		goto err_register;
1159 
1160 	err = register_netdev(ip6n->fb_tnl_dev);
1161 	if (err < 0)
1162 		goto err_register;
1163 
1164 	t = netdev_priv(ip6n->fb_tnl_dev);
1165 
1166 	strcpy(t->parms.name, ip6n->fb_tnl_dev->name);
1167 	return 0;
1168 
1169 err_register:
1170 	free_netdev(ip6n->fb_tnl_dev);
1171 err_alloc_dev:
1172 	return err;
1173 }
1174 
1175 static void __net_exit vti6_exit_batch_net(struct list_head *net_list)
1176 {
1177 	struct vti6_net *ip6n;
1178 	struct net *net;
1179 	LIST_HEAD(list);
1180 
1181 	rtnl_lock();
1182 	list_for_each_entry(net, net_list, exit_list) {
1183 		ip6n = net_generic(net, vti6_net_id);
1184 		vti6_destroy_tunnels(ip6n, &list);
1185 	}
1186 	unregister_netdevice_many(&list);
1187 	rtnl_unlock();
1188 }
1189 
1190 static struct pernet_operations vti6_net_ops = {
1191 	.init = vti6_init_net,
1192 	.exit_batch = vti6_exit_batch_net,
1193 	.id   = &vti6_net_id,
1194 	.size = sizeof(struct vti6_net),
1195 };
1196 
1197 static struct xfrm6_protocol vti_esp6_protocol __read_mostly = {
1198 	.handler	=	vti6_rcv,
1199 	.input_handler	=	vti6_input_proto,
1200 	.cb_handler	=	vti6_rcv_cb,
1201 	.err_handler	=	vti6_err,
1202 	.priority	=	100,
1203 };
1204 
1205 static struct xfrm6_protocol vti_ah6_protocol __read_mostly = {
1206 	.handler	=	vti6_rcv,
1207 	.input_handler	=	vti6_input_proto,
1208 	.cb_handler	=	vti6_rcv_cb,
1209 	.err_handler	=	vti6_err,
1210 	.priority	=	100,
1211 };
1212 
1213 static struct xfrm6_protocol vti_ipcomp6_protocol __read_mostly = {
1214 	.handler	=	vti6_rcv,
1215 	.input_handler	=	vti6_input_proto,
1216 	.cb_handler	=	vti6_rcv_cb,
1217 	.err_handler	=	vti6_err,
1218 	.priority	=	100,
1219 };
1220 
1221 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1222 static int vti6_rcv_tunnel(struct sk_buff *skb)
1223 {
1224 	const xfrm_address_t *saddr;
1225 	__be32 spi;
1226 
1227 	saddr = (const xfrm_address_t *)&ipv6_hdr(skb)->saddr;
1228 	spi = xfrm6_tunnel_spi_lookup(dev_net(skb->dev), saddr);
1229 
1230 	return vti6_input_proto(skb, IPPROTO_IPV6, spi, 0);
1231 }
1232 
1233 static struct xfrm6_tunnel vti_ipv6_handler __read_mostly = {
1234 	.handler	=	vti6_rcv_tunnel,
1235 	.cb_handler	=	vti6_rcv_cb,
1236 	.err_handler	=	vti6_err,
1237 	.priority	=	0,
1238 };
1239 
1240 static struct xfrm6_tunnel vti_ip6ip_handler __read_mostly = {
1241 	.handler	=	vti6_rcv_tunnel,
1242 	.cb_handler	=	vti6_rcv_cb,
1243 	.err_handler	=	vti6_err,
1244 	.priority	=	0,
1245 };
1246 #endif
1247 
1248 /**
1249  * vti6_tunnel_init - register protocol and reserve needed resources
1250  *
1251  * Return: 0 on success
1252  **/
1253 static int __init vti6_tunnel_init(void)
1254 {
1255 	const char *msg;
1256 	int err;
1257 
1258 	msg = "tunnel device";
1259 	err = register_pernet_device(&vti6_net_ops);
1260 	if (err < 0)
1261 		goto pernet_dev_failed;
1262 
1263 	msg = "tunnel protocols";
1264 	err = xfrm6_protocol_register(&vti_esp6_protocol, IPPROTO_ESP);
1265 	if (err < 0)
1266 		goto xfrm_proto_esp_failed;
1267 	err = xfrm6_protocol_register(&vti_ah6_protocol, IPPROTO_AH);
1268 	if (err < 0)
1269 		goto xfrm_proto_ah_failed;
1270 	err = xfrm6_protocol_register(&vti_ipcomp6_protocol, IPPROTO_COMP);
1271 	if (err < 0)
1272 		goto xfrm_proto_comp_failed;
1273 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1274 	msg = "ipv6 tunnel";
1275 	err = xfrm6_tunnel_register(&vti_ipv6_handler, AF_INET6);
1276 	if (err < 0)
1277 		goto vti_tunnel_ipv6_failed;
1278 	err = xfrm6_tunnel_register(&vti_ip6ip_handler, AF_INET);
1279 	if (err < 0)
1280 		goto vti_tunnel_ip6ip_failed;
1281 #endif
1282 
1283 	msg = "netlink interface";
1284 	err = rtnl_link_register(&vti6_link_ops);
1285 	if (err < 0)
1286 		goto rtnl_link_failed;
1287 
1288 	return 0;
1289 
1290 rtnl_link_failed:
1291 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1292 	err = xfrm6_tunnel_deregister(&vti_ip6ip_handler, AF_INET);
1293 vti_tunnel_ip6ip_failed:
1294 	err = xfrm6_tunnel_deregister(&vti_ipv6_handler, AF_INET6);
1295 vti_tunnel_ipv6_failed:
1296 #endif
1297 	xfrm6_protocol_deregister(&vti_ipcomp6_protocol, IPPROTO_COMP);
1298 xfrm_proto_comp_failed:
1299 	xfrm6_protocol_deregister(&vti_ah6_protocol, IPPROTO_AH);
1300 xfrm_proto_ah_failed:
1301 	xfrm6_protocol_deregister(&vti_esp6_protocol, IPPROTO_ESP);
1302 xfrm_proto_esp_failed:
1303 	unregister_pernet_device(&vti6_net_ops);
1304 pernet_dev_failed:
1305 	pr_err("vti6 init: failed to register %s\n", msg);
1306 	return err;
1307 }
1308 
1309 /**
1310  * vti6_tunnel_cleanup - free resources and unregister protocol
1311  **/
1312 static void __exit vti6_tunnel_cleanup(void)
1313 {
1314 	rtnl_link_unregister(&vti6_link_ops);
1315 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1316 	xfrm6_tunnel_deregister(&vti_ip6ip_handler, AF_INET);
1317 	xfrm6_tunnel_deregister(&vti_ipv6_handler, AF_INET6);
1318 #endif
1319 	xfrm6_protocol_deregister(&vti_ipcomp6_protocol, IPPROTO_COMP);
1320 	xfrm6_protocol_deregister(&vti_ah6_protocol, IPPROTO_AH);
1321 	xfrm6_protocol_deregister(&vti_esp6_protocol, IPPROTO_ESP);
1322 	unregister_pernet_device(&vti6_net_ops);
1323 }
1324 
1325 module_init(vti6_tunnel_init);
1326 module_exit(vti6_tunnel_cleanup);
1327 MODULE_LICENSE("GPL");
1328 MODULE_ALIAS_RTNL_LINK("vti6");
1329 MODULE_ALIAS_NETDEV("ip6_vti0");
1330 MODULE_AUTHOR("Steffen Klassert");
1331 MODULE_DESCRIPTION("IPv6 virtual tunnel interface");
1332