xref: /linux/net/ipv6/ip6_vti.c (revision c21614d5c0e76cf1d7a864f15d495fd3e5876acc)
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 	vti6_tnl_link(ip6n, t);
197 
198 	return 0;
199 
200 out:
201 	return err;
202 }
203 
204 static struct ip6_tnl *vti6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
205 {
206 	struct net_device *dev;
207 	struct ip6_tnl *t;
208 	char name[IFNAMSIZ];
209 	int err;
210 
211 	if (p->name[0]) {
212 		if (!dev_valid_name(p->name))
213 			goto failed;
214 		strscpy(name, p->name, IFNAMSIZ);
215 	} else {
216 		sprintf(name, "ip6_vti%%d");
217 	}
218 
219 	dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, vti6_dev_setup);
220 	if (!dev)
221 		goto failed;
222 
223 	dev_net_set(dev, net);
224 
225 	t = netdev_priv(dev);
226 	t->parms = *p;
227 	t->net = dev_net(dev);
228 
229 	err = vti6_tnl_create2(dev);
230 	if (err < 0)
231 		goto failed_free;
232 
233 	return t;
234 
235 failed_free:
236 	free_netdev(dev);
237 failed:
238 	return NULL;
239 }
240 
241 /**
242  * vti6_locate - find or create tunnel matching given parameters
243  *   @net: network namespace
244  *   @p: tunnel parameters
245  *   @create: != 0 if allowed to create new tunnel if no match found
246  *
247  * Description:
248  *   vti6_locate() first tries to locate an existing tunnel
249  *   based on @parms. If this is unsuccessful, but @create is set a new
250  *   tunnel device is created and registered for use.
251  *
252  * Return:
253  *   matching tunnel or NULL
254  **/
255 static struct ip6_tnl *vti6_locate(struct net *net, struct __ip6_tnl_parm *p,
256 				   int create)
257 {
258 	const struct in6_addr *remote = &p->raddr;
259 	const struct in6_addr *local = &p->laddr;
260 	struct ip6_tnl __rcu **tp;
261 	struct ip6_tnl *t;
262 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
263 
264 	for (tp = vti6_tnl_bucket(ip6n, p);
265 	     (t = rtnl_dereference(*tp)) != NULL;
266 	     tp = &t->next) {
267 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
268 		    ipv6_addr_equal(remote, &t->parms.raddr)) {
269 			if (create)
270 				return NULL;
271 
272 			return t;
273 		}
274 	}
275 	if (!create)
276 		return NULL;
277 	return vti6_tnl_create(net, p);
278 }
279 
280 /**
281  * vti6_dev_uninit - tunnel device uninitializer
282  *   @dev: the device to be destroyed
283  *
284  * Description:
285  *   vti6_dev_uninit() removes tunnel from its list
286  **/
287 static void vti6_dev_uninit(struct net_device *dev)
288 {
289 	struct ip6_tnl *t = netdev_priv(dev);
290 	struct vti6_net *ip6n = net_generic(t->net, vti6_net_id);
291 
292 	if (dev == ip6n->fb_tnl_dev)
293 		RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
294 	else
295 		vti6_tnl_unlink(ip6n, t);
296 	netdev_put(dev, &t->dev_tracker);
297 }
298 
299 static int vti6_input_proto(struct sk_buff *skb, int nexthdr, __be32 spi,
300 			    int encap_type)
301 {
302 	struct ip6_tnl *t;
303 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
304 
305 	rcu_read_lock();
306 	t = vti6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
307 	if (t) {
308 		if (t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) {
309 			rcu_read_unlock();
310 			goto discard;
311 		}
312 
313 		if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
314 			rcu_read_unlock();
315 			goto discard;
316 		}
317 
318 		ipv6h = ipv6_hdr(skb);
319 		if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
320 			DEV_STATS_INC(t->dev, rx_dropped);
321 			rcu_read_unlock();
322 			goto discard;
323 		}
324 
325 		rcu_read_unlock();
326 
327 		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
328 		XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
329 		XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
330 		return xfrm_input(skb, nexthdr, spi, encap_type);
331 	}
332 	rcu_read_unlock();
333 	return -EINVAL;
334 discard:
335 	kfree_skb(skb);
336 	return 0;
337 }
338 
339 static int vti6_rcv(struct sk_buff *skb)
340 {
341 	int nexthdr = skb_network_header(skb)[IP6CB(skb)->nhoff];
342 
343 	return vti6_input_proto(skb, nexthdr, 0, 0);
344 }
345 
346 static int vti6_rcv_cb(struct sk_buff *skb, int err)
347 {
348 	unsigned short family;
349 	struct net_device *dev;
350 	struct xfrm_state *x;
351 	const struct xfrm_mode *inner_mode;
352 	struct ip6_tnl *t = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6;
353 	u32 orig_mark = skb->mark;
354 	int ret;
355 
356 	if (!t)
357 		return 1;
358 
359 	dev = t->dev;
360 
361 	if (err) {
362 		DEV_STATS_INC(dev, rx_errors);
363 		DEV_STATS_INC(dev, rx_dropped);
364 
365 		return 0;
366 	}
367 
368 	x = xfrm_input_state(skb);
369 
370 	inner_mode = &x->inner_mode;
371 
372 	if (x->sel.family == AF_UNSPEC) {
373 		inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
374 		if (inner_mode == NULL) {
375 			XFRM_INC_STATS(dev_net(skb->dev),
376 				       LINUX_MIB_XFRMINSTATEMODEERROR);
377 			return -EINVAL;
378 		}
379 	}
380 
381 	family = inner_mode->family;
382 
383 	skb->mark = be32_to_cpu(t->parms.i_key);
384 	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
385 	skb->mark = orig_mark;
386 
387 	if (!ret)
388 		return -EPERM;
389 
390 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(skb->dev)));
391 	skb->dev = dev;
392 	dev_sw_netstats_rx_add(dev, skb->len);
393 
394 	return 0;
395 }
396 
397 /**
398  * vti6_addr_conflict - compare packet addresses to tunnel's own
399  *   @t: the outgoing tunnel device
400  *   @hdr: IPv6 header from the incoming packet
401  *
402  * Description:
403  *   Avoid trivial tunneling loop by checking that tunnel exit-point
404  *   doesn't match source of incoming packet.
405  *
406  * Return:
407  *   1 if conflict,
408  *   0 else
409  **/
410 static inline bool
411 vti6_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
412 {
413 	return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
414 }
415 
416 static bool vti6_state_check(const struct xfrm_state *x,
417 			     const struct in6_addr *dst,
418 			     const struct in6_addr *src)
419 {
420 	xfrm_address_t *daddr = (xfrm_address_t *)dst;
421 	xfrm_address_t *saddr = (xfrm_address_t *)src;
422 
423 	/* if there is no transform then this tunnel is not functional.
424 	 * Or if the xfrm is not mode tunnel.
425 	 */
426 	if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
427 	    x->props.family != AF_INET6)
428 		return false;
429 
430 	if (ipv6_addr_any(dst))
431 		return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET6);
432 
433 	if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET6))
434 		return false;
435 
436 	return true;
437 }
438 
439 /**
440  * vti6_xmit - send a packet
441  *   @skb: the outgoing socket buffer
442  *   @dev: the outgoing tunnel device
443  *   @fl: the flow informations for the xfrm_lookup
444  **/
445 static int
446 vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
447 {
448 	struct ip6_tnl *t = netdev_priv(dev);
449 	struct dst_entry *dst = skb_dst(skb);
450 	struct net_device *tdev;
451 	struct xfrm_state *x;
452 	int pkt_len = skb->len;
453 	int err = -1;
454 	int mtu;
455 
456 	if (!dst) {
457 		switch (skb->protocol) {
458 		case htons(ETH_P_IP): {
459 			struct rtable *rt;
460 
461 			fl->u.ip4.flowi4_oif = dev->ifindex;
462 			fl->u.ip4.flowi4_flags |= FLOWI_FLAG_ANYSRC;
463 			rt = __ip_route_output_key(dev_net(dev), &fl->u.ip4);
464 			if (IS_ERR(rt))
465 				goto tx_err_link_failure;
466 			dst = &rt->dst;
467 			skb_dst_set(skb, dst);
468 			break;
469 		}
470 		case htons(ETH_P_IPV6):
471 			fl->u.ip6.flowi6_oif = dev->ifindex;
472 			fl->u.ip6.flowi6_flags |= FLOWI_FLAG_ANYSRC;
473 			dst = ip6_route_output(dev_net(dev), NULL, &fl->u.ip6);
474 			if (dst->error) {
475 				dst_release(dst);
476 				dst = NULL;
477 				goto tx_err_link_failure;
478 			}
479 			skb_dst_set(skb, dst);
480 			break;
481 		default:
482 			goto tx_err_link_failure;
483 		}
484 	}
485 
486 	dst_hold(dst);
487 	dst = xfrm_lookup_route(t->net, dst, fl, NULL, 0);
488 	if (IS_ERR(dst)) {
489 		err = PTR_ERR(dst);
490 		dst = NULL;
491 		goto tx_err_link_failure;
492 	}
493 
494 	if (dst->flags & DST_XFRM_QUEUE)
495 		goto xmit;
496 
497 	x = dst->xfrm;
498 	if (!vti6_state_check(x, &t->parms.raddr, &t->parms.laddr))
499 		goto tx_err_link_failure;
500 
501 	if (!ip6_tnl_xmit_ctl(t, (const struct in6_addr *)&x->props.saddr,
502 			      (const struct in6_addr *)&x->id.daddr))
503 		goto tx_err_link_failure;
504 
505 	tdev = dst->dev;
506 
507 	if (tdev == dev) {
508 		DEV_STATS_INC(dev, collisions);
509 		net_warn_ratelimited("%s: Local routing loop detected!\n",
510 				     t->parms.name);
511 		goto tx_err_dst_release;
512 	}
513 
514 	mtu = dst_mtu(dst);
515 	if (skb->len > mtu) {
516 		skb_dst_update_pmtu_no_confirm(skb, mtu);
517 
518 		if (skb->protocol == htons(ETH_P_IPV6)) {
519 			if (mtu < IPV6_MIN_MTU)
520 				mtu = IPV6_MIN_MTU;
521 
522 			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
523 		} else {
524 			if (!(ip_hdr(skb)->frag_off & htons(IP_DF)))
525 				goto xmit;
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 xmit:
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 	DEV_STATS_INC(dev, 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 flowi fl;
558 	int ret;
559 
560 	if (!pskb_inet_may_pull(skb))
561 		goto tx_err;
562 
563 	memset(&fl, 0, sizeof(fl));
564 
565 	switch (skb->protocol) {
566 	case htons(ETH_P_IPV6):
567 		if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) ||
568 		    vti6_addr_conflict(t, ipv6_hdr(skb)))
569 			goto tx_err;
570 
571 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
572 		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET6);
573 		break;
574 	case htons(ETH_P_IP):
575 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
576 		xfrm_decode_session(dev_net(dev), skb, &fl, AF_INET);
577 		break;
578 	default:
579 		goto tx_err;
580 	}
581 
582 	/* override mark with tunnel output key */
583 	fl.flowi_mark = be32_to_cpu(t->parms.o_key);
584 
585 	ret = vti6_xmit(skb, dev, &fl);
586 	if (ret < 0)
587 		goto tx_err;
588 
589 	return NETDEV_TX_OK;
590 
591 tx_err:
592 	DEV_STATS_INC(dev, tx_errors);
593 	DEV_STATS_INC(dev, tx_dropped);
594 	kfree_skb(skb);
595 	return NETDEV_TX_OK;
596 }
597 
598 static int vti6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
599 		    u8 type, u8 code, int offset, __be32 info)
600 {
601 	__be32 spi;
602 	__u32 mark;
603 	struct xfrm_state *x;
604 	struct ip6_tnl *t;
605 	struct ip_esp_hdr *esph;
606 	struct ip_auth_hdr *ah;
607 	struct ip_comp_hdr *ipch;
608 	struct net *net = dev_net(skb->dev);
609 	const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
610 	int protocol = iph->nexthdr;
611 
612 	t = vti6_tnl_lookup(dev_net(skb->dev), &iph->daddr, &iph->saddr);
613 	if (!t)
614 		return -1;
615 
616 	mark = be32_to_cpu(t->parms.o_key);
617 
618 	switch (protocol) {
619 	case IPPROTO_ESP:
620 		esph = (struct ip_esp_hdr *)(skb->data + offset);
621 		spi = esph->spi;
622 		break;
623 	case IPPROTO_AH:
624 		ah = (struct ip_auth_hdr *)(skb->data + offset);
625 		spi = ah->spi;
626 		break;
627 	case IPPROTO_COMP:
628 		ipch = (struct ip_comp_hdr *)(skb->data + offset);
629 		spi = htonl(ntohs(ipch->cpi));
630 		break;
631 	default:
632 		return 0;
633 	}
634 
635 	if (type != ICMPV6_PKT_TOOBIG &&
636 	    type != NDISC_REDIRECT)
637 		return 0;
638 
639 	x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
640 			      spi, protocol, AF_INET6);
641 	if (!x)
642 		return 0;
643 
644 	if (type == NDISC_REDIRECT)
645 		ip6_redirect(skb, net, skb->dev->ifindex, 0,
646 			     sock_net_uid(net, NULL));
647 	else
648 		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
649 	xfrm_state_put(x);
650 
651 	return 0;
652 }
653 
654 static void vti6_link_config(struct ip6_tnl *t, bool keep_mtu)
655 {
656 	struct net_device *dev = t->dev;
657 	struct __ip6_tnl_parm *p = &t->parms;
658 	struct net_device *tdev = NULL;
659 	int mtu;
660 
661 	__dev_addr_set(dev, &p->laddr, sizeof(struct in6_addr));
662 	memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
663 
664 	p->flags &= ~(IP6_TNL_F_CAP_XMIT | IP6_TNL_F_CAP_RCV |
665 		      IP6_TNL_F_CAP_PER_PACKET);
666 	p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
667 
668 	if (p->flags & IP6_TNL_F_CAP_XMIT && p->flags & IP6_TNL_F_CAP_RCV)
669 		dev->flags |= IFF_POINTOPOINT;
670 	else
671 		dev->flags &= ~IFF_POINTOPOINT;
672 
673 	if (keep_mtu && dev->mtu) {
674 		dev->mtu = clamp(dev->mtu, dev->min_mtu, dev->max_mtu);
675 		return;
676 	}
677 
678 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
679 		int strict = (ipv6_addr_type(&p->raddr) &
680 			      (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
681 		struct rt6_info *rt = rt6_lookup(t->net,
682 						 &p->raddr, &p->laddr,
683 						 p->link, NULL, strict);
684 
685 		if (rt)
686 			tdev = rt->dst.dev;
687 		ip6_rt_put(rt);
688 	}
689 
690 	if (!tdev && p->link)
691 		tdev = __dev_get_by_index(t->net, p->link);
692 
693 	if (tdev)
694 		mtu = tdev->mtu - sizeof(struct ipv6hdr);
695 	else
696 		mtu = ETH_DATA_LEN - LL_MAX_HEADER - sizeof(struct ipv6hdr);
697 
698 	dev->mtu = max_t(int, mtu, IPV4_MIN_MTU);
699 }
700 
701 /**
702  * vti6_tnl_change - update the tunnel parameters
703  *   @t: tunnel to be changed
704  *   @p: tunnel configuration parameters
705  *   @keep_mtu: MTU was set from userspace, don't re-compute it
706  *
707  * Description:
708  *   vti6_tnl_change() updates the tunnel parameters
709  **/
710 static int
711 vti6_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p,
712 		bool keep_mtu)
713 {
714 	t->parms.laddr = p->laddr;
715 	t->parms.raddr = p->raddr;
716 	t->parms.link = p->link;
717 	t->parms.i_key = p->i_key;
718 	t->parms.o_key = p->o_key;
719 	t->parms.proto = p->proto;
720 	t->parms.fwmark = p->fwmark;
721 	dst_cache_reset(&t->dst_cache);
722 	vti6_link_config(t, keep_mtu);
723 	return 0;
724 }
725 
726 static int vti6_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p,
727 		       bool keep_mtu)
728 {
729 	struct net *net = dev_net(t->dev);
730 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
731 	int err;
732 
733 	vti6_tnl_unlink(ip6n, t);
734 	synchronize_net();
735 	err = vti6_tnl_change(t, p, keep_mtu);
736 	vti6_tnl_link(ip6n, t);
737 	netdev_state_change(t->dev);
738 	return err;
739 }
740 
741 static void
742 vti6_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm2 *u)
743 {
744 	p->laddr = u->laddr;
745 	p->raddr = u->raddr;
746 	p->link = u->link;
747 	p->i_key = u->i_key;
748 	p->o_key = u->o_key;
749 	p->proto = u->proto;
750 
751 	memcpy(p->name, u->name, sizeof(u->name));
752 }
753 
754 static void
755 vti6_parm_to_user(struct ip6_tnl_parm2 *u, const struct __ip6_tnl_parm *p)
756 {
757 	u->laddr = p->laddr;
758 	u->raddr = p->raddr;
759 	u->link = p->link;
760 	u->i_key = p->i_key;
761 	u->o_key = p->o_key;
762 	if (u->i_key)
763 		u->i_flags |= GRE_KEY;
764 	if (u->o_key)
765 		u->o_flags |= GRE_KEY;
766 	u->proto = p->proto;
767 
768 	memcpy(u->name, p->name, sizeof(u->name));
769 }
770 
771 /**
772  * vti6_siocdevprivate - configure vti6 tunnels from userspace
773  *   @dev: virtual device associated with tunnel
774  *   @ifr: unused
775  *   @data: parameters passed from userspace
776  *   @cmd: command to be performed
777  *
778  * Description:
779  *   vti6_siocdevprivate() 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_siocdevprivate(struct net_device *dev, struct ifreq *ifr, void __user *data, 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 	memset(&p1, 0, sizeof(p1));
810 
811 	switch (cmd) {
812 	case SIOCGETTUNNEL:
813 		if (dev == ip6n->fb_tnl_dev) {
814 			if (copy_from_user(&p, data, sizeof(p))) {
815 				err = -EFAULT;
816 				break;
817 			}
818 			vti6_parm_from_user(&p1, &p);
819 			t = vti6_locate(net, &p1, 0);
820 		} else {
821 			memset(&p, 0, sizeof(p));
822 		}
823 		if (!t)
824 			t = netdev_priv(dev);
825 		vti6_parm_to_user(&p, &t->parms);
826 		if (copy_to_user(data, &p, sizeof(p)))
827 			err = -EFAULT;
828 		break;
829 	case SIOCADDTUNNEL:
830 	case SIOCCHGTUNNEL:
831 		err = -EPERM;
832 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
833 			break;
834 		err = -EFAULT;
835 		if (copy_from_user(&p, data, sizeof(p)))
836 			break;
837 		err = -EINVAL;
838 		if (p.proto != IPPROTO_IPV6  && p.proto != 0)
839 			break;
840 		vti6_parm_from_user(&p1, &p);
841 		t = vti6_locate(net, &p1, cmd == SIOCADDTUNNEL);
842 		if (dev != ip6n->fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
843 			if (t) {
844 				if (t->dev != dev) {
845 					err = -EEXIST;
846 					break;
847 				}
848 			} else
849 				t = netdev_priv(dev);
850 
851 			err = vti6_update(t, &p1, false);
852 		}
853 		if (t) {
854 			err = 0;
855 			vti6_parm_to_user(&p, &t->parms);
856 			if (copy_to_user(data, &p, sizeof(p)))
857 				err = -EFAULT;
858 
859 		} else
860 			err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
861 		break;
862 	case SIOCDELTUNNEL:
863 		err = -EPERM;
864 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
865 			break;
866 
867 		if (dev == ip6n->fb_tnl_dev) {
868 			err = -EFAULT;
869 			if (copy_from_user(&p, data, sizeof(p)))
870 				break;
871 			err = -ENOENT;
872 			vti6_parm_from_user(&p1, &p);
873 			t = vti6_locate(net, &p1, 0);
874 			if (!t)
875 				break;
876 			err = -EPERM;
877 			if (t->dev == ip6n->fb_tnl_dev)
878 				break;
879 			dev = t->dev;
880 		}
881 		err = 0;
882 		unregister_netdevice(dev);
883 		break;
884 	default:
885 		err = -EINVAL;
886 	}
887 	return err;
888 }
889 
890 static const struct net_device_ops vti6_netdev_ops = {
891 	.ndo_init	= vti6_dev_init,
892 	.ndo_uninit	= vti6_dev_uninit,
893 	.ndo_start_xmit = vti6_tnl_xmit,
894 	.ndo_siocdevprivate = vti6_siocdevprivate,
895 	.ndo_get_stats64 = dev_get_tstats64,
896 	.ndo_get_iflink = ip6_tnl_get_iflink,
897 };
898 
899 /**
900  * vti6_dev_setup - setup virtual tunnel device
901  *   @dev: virtual device associated with tunnel
902  *
903  * Description:
904  *   Initialize function pointers and device parameters
905  **/
906 static void vti6_dev_setup(struct net_device *dev)
907 {
908 	dev->netdev_ops = &vti6_netdev_ops;
909 	dev->header_ops = &ip_tunnel_header_ops;
910 	dev->needs_free_netdev = true;
911 	dev->priv_destructor = vti6_dev_free;
912 
913 	dev->type = ARPHRD_TUNNEL6;
914 	dev->min_mtu = IPV4_MIN_MTU;
915 	dev->max_mtu = IP_MAX_MTU - sizeof(struct ipv6hdr);
916 	dev->flags |= IFF_NOARP;
917 	dev->addr_len = sizeof(struct in6_addr);
918 	netif_keep_dst(dev);
919 	/* This perm addr will be used as interface identifier by IPv6 */
920 	dev->addr_assign_type = NET_ADDR_RANDOM;
921 	eth_random_addr(dev->perm_addr);
922 }
923 
924 /**
925  * vti6_dev_init_gen - general initializer for all tunnel devices
926  *   @dev: virtual device associated with tunnel
927  **/
928 static inline int vti6_dev_init_gen(struct net_device *dev)
929 {
930 	struct ip6_tnl *t = netdev_priv(dev);
931 
932 	t->dev = dev;
933 	t->net = dev_net(dev);
934 	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
935 	if (!dev->tstats)
936 		return -ENOMEM;
937 	netdev_hold(dev, &t->dev_tracker, GFP_KERNEL);
938 	netdev_lockdep_set_classes(dev);
939 	return 0;
940 }
941 
942 /**
943  * vti6_dev_init - initializer for all non fallback tunnel devices
944  *   @dev: virtual device associated with tunnel
945  **/
946 static int vti6_dev_init(struct net_device *dev)
947 {
948 	struct ip6_tnl *t = netdev_priv(dev);
949 	int err = vti6_dev_init_gen(dev);
950 
951 	if (err)
952 		return err;
953 	vti6_link_config(t, true);
954 	return 0;
955 }
956 
957 /**
958  * vti6_fb_tnl_dev_init - initializer for fallback tunnel device
959  *   @dev: fallback device
960  *
961  * Return: 0
962  **/
963 static int __net_init vti6_fb_tnl_dev_init(struct net_device *dev)
964 {
965 	struct ip6_tnl *t = netdev_priv(dev);
966 	struct net *net = dev_net(dev);
967 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
968 
969 	t->parms.proto = IPPROTO_IPV6;
970 
971 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
972 	return 0;
973 }
974 
975 static int vti6_validate(struct nlattr *tb[], struct nlattr *data[],
976 			 struct netlink_ext_ack *extack)
977 {
978 	return 0;
979 }
980 
981 static void vti6_netlink_parms(struct nlattr *data[],
982 			       struct __ip6_tnl_parm *parms)
983 {
984 	memset(parms, 0, sizeof(*parms));
985 
986 	if (!data)
987 		return;
988 
989 	if (data[IFLA_VTI_LINK])
990 		parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
991 
992 	if (data[IFLA_VTI_LOCAL])
993 		parms->laddr = nla_get_in6_addr(data[IFLA_VTI_LOCAL]);
994 
995 	if (data[IFLA_VTI_REMOTE])
996 		parms->raddr = nla_get_in6_addr(data[IFLA_VTI_REMOTE]);
997 
998 	if (data[IFLA_VTI_IKEY])
999 		parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
1000 
1001 	if (data[IFLA_VTI_OKEY])
1002 		parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
1003 
1004 	if (data[IFLA_VTI_FWMARK])
1005 		parms->fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]);
1006 }
1007 
1008 static int vti6_newlink(struct net *src_net, struct net_device *dev,
1009 			struct nlattr *tb[], struct nlattr *data[],
1010 			struct netlink_ext_ack *extack)
1011 {
1012 	struct net *net = dev_net(dev);
1013 	struct ip6_tnl *nt;
1014 
1015 	nt = netdev_priv(dev);
1016 	vti6_netlink_parms(data, &nt->parms);
1017 
1018 	nt->parms.proto = IPPROTO_IPV6;
1019 
1020 	if (vti6_locate(net, &nt->parms, 0))
1021 		return -EEXIST;
1022 
1023 	return vti6_tnl_create2(dev);
1024 }
1025 
1026 static void vti6_dellink(struct net_device *dev, struct list_head *head)
1027 {
1028 	struct net *net = dev_net(dev);
1029 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
1030 
1031 	if (dev != ip6n->fb_tnl_dev)
1032 		unregister_netdevice_queue(dev, head);
1033 }
1034 
1035 static int vti6_changelink(struct net_device *dev, struct nlattr *tb[],
1036 			   struct nlattr *data[],
1037 			   struct netlink_ext_ack *extack)
1038 {
1039 	struct ip6_tnl *t;
1040 	struct __ip6_tnl_parm p;
1041 	struct net *net = dev_net(dev);
1042 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
1043 
1044 	if (dev == ip6n->fb_tnl_dev)
1045 		return -EINVAL;
1046 
1047 	vti6_netlink_parms(data, &p);
1048 
1049 	t = vti6_locate(net, &p, 0);
1050 
1051 	if (t) {
1052 		if (t->dev != dev)
1053 			return -EEXIST;
1054 	} else
1055 		t = netdev_priv(dev);
1056 
1057 	return vti6_update(t, &p, tb && tb[IFLA_MTU]);
1058 }
1059 
1060 static size_t vti6_get_size(const struct net_device *dev)
1061 {
1062 	return
1063 		/* IFLA_VTI_LINK */
1064 		nla_total_size(4) +
1065 		/* IFLA_VTI_LOCAL */
1066 		nla_total_size(sizeof(struct in6_addr)) +
1067 		/* IFLA_VTI_REMOTE */
1068 		nla_total_size(sizeof(struct in6_addr)) +
1069 		/* IFLA_VTI_IKEY */
1070 		nla_total_size(4) +
1071 		/* IFLA_VTI_OKEY */
1072 		nla_total_size(4) +
1073 		/* IFLA_VTI_FWMARK */
1074 		nla_total_size(4) +
1075 		0;
1076 }
1077 
1078 static int vti6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1079 {
1080 	struct ip6_tnl *tunnel = netdev_priv(dev);
1081 	struct __ip6_tnl_parm *parm = &tunnel->parms;
1082 
1083 	if (nla_put_u32(skb, IFLA_VTI_LINK, parm->link) ||
1084 	    nla_put_in6_addr(skb, IFLA_VTI_LOCAL, &parm->laddr) ||
1085 	    nla_put_in6_addr(skb, IFLA_VTI_REMOTE, &parm->raddr) ||
1086 	    nla_put_be32(skb, IFLA_VTI_IKEY, parm->i_key) ||
1087 	    nla_put_be32(skb, IFLA_VTI_OKEY, parm->o_key) ||
1088 	    nla_put_u32(skb, IFLA_VTI_FWMARK, parm->fwmark))
1089 		goto nla_put_failure;
1090 	return 0;
1091 
1092 nla_put_failure:
1093 	return -EMSGSIZE;
1094 }
1095 
1096 static const struct nla_policy vti6_policy[IFLA_VTI_MAX + 1] = {
1097 	[IFLA_VTI_LINK]		= { .type = NLA_U32 },
1098 	[IFLA_VTI_LOCAL]	= { .len = sizeof(struct in6_addr) },
1099 	[IFLA_VTI_REMOTE]	= { .len = sizeof(struct in6_addr) },
1100 	[IFLA_VTI_IKEY]		= { .type = NLA_U32 },
1101 	[IFLA_VTI_OKEY]		= { .type = NLA_U32 },
1102 	[IFLA_VTI_FWMARK]	= { .type = NLA_U32 },
1103 };
1104 
1105 static struct rtnl_link_ops vti6_link_ops __read_mostly = {
1106 	.kind		= "vti6",
1107 	.maxtype	= IFLA_VTI_MAX,
1108 	.policy		= vti6_policy,
1109 	.priv_size	= sizeof(struct ip6_tnl),
1110 	.setup		= vti6_dev_setup,
1111 	.validate	= vti6_validate,
1112 	.newlink	= vti6_newlink,
1113 	.dellink	= vti6_dellink,
1114 	.changelink	= vti6_changelink,
1115 	.get_size	= vti6_get_size,
1116 	.fill_info	= vti6_fill_info,
1117 	.get_link_net	= ip6_tnl_get_link_net,
1118 };
1119 
1120 static void __net_exit vti6_destroy_tunnels(struct vti6_net *ip6n,
1121 					    struct list_head *list)
1122 {
1123 	int h;
1124 	struct ip6_tnl *t;
1125 
1126 	for (h = 0; h < IP6_VTI_HASH_SIZE; h++) {
1127 		t = rtnl_dereference(ip6n->tnls_r_l[h]);
1128 		while (t) {
1129 			unregister_netdevice_queue(t->dev, list);
1130 			t = rtnl_dereference(t->next);
1131 		}
1132 	}
1133 
1134 	t = rtnl_dereference(ip6n->tnls_wc[0]);
1135 	if (t)
1136 		unregister_netdevice_queue(t->dev, list);
1137 }
1138 
1139 static int __net_init vti6_init_net(struct net *net)
1140 {
1141 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
1142 	struct ip6_tnl *t = NULL;
1143 	int err;
1144 
1145 	ip6n->tnls[0] = ip6n->tnls_wc;
1146 	ip6n->tnls[1] = ip6n->tnls_r_l;
1147 
1148 	if (!net_has_fallback_tunnels(net))
1149 		return 0;
1150 	err = -ENOMEM;
1151 	ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6_vti0",
1152 					NET_NAME_UNKNOWN, vti6_dev_setup);
1153 
1154 	if (!ip6n->fb_tnl_dev)
1155 		goto err_alloc_dev;
1156 	dev_net_set(ip6n->fb_tnl_dev, net);
1157 	ip6n->fb_tnl_dev->rtnl_link_ops = &vti6_link_ops;
1158 
1159 	err = vti6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
1160 	if (err < 0)
1161 		goto err_register;
1162 
1163 	err = register_netdev(ip6n->fb_tnl_dev);
1164 	if (err < 0)
1165 		goto err_register;
1166 
1167 	t = netdev_priv(ip6n->fb_tnl_dev);
1168 
1169 	strcpy(t->parms.name, ip6n->fb_tnl_dev->name);
1170 	return 0;
1171 
1172 err_register:
1173 	free_netdev(ip6n->fb_tnl_dev);
1174 err_alloc_dev:
1175 	return err;
1176 }
1177 
1178 static void __net_exit vti6_exit_batch_rtnl(struct list_head *net_list,
1179 					    struct list_head *dev_to_kill)
1180 {
1181 	struct vti6_net *ip6n;
1182 	struct net *net;
1183 
1184 	ASSERT_RTNL();
1185 	list_for_each_entry(net, net_list, exit_list) {
1186 		ip6n = net_generic(net, vti6_net_id);
1187 		vti6_destroy_tunnels(ip6n, dev_to_kill);
1188 	}
1189 }
1190 
1191 static struct pernet_operations vti6_net_ops = {
1192 	.init = vti6_init_net,
1193 	.exit_batch_rtnl = vti6_exit_batch_rtnl,
1194 	.id   = &vti6_net_id,
1195 	.size = sizeof(struct vti6_net),
1196 };
1197 
1198 static struct xfrm6_protocol vti_esp6_protocol __read_mostly = {
1199 	.handler	=	vti6_rcv,
1200 	.input_handler	=	vti6_input_proto,
1201 	.cb_handler	=	vti6_rcv_cb,
1202 	.err_handler	=	vti6_err,
1203 	.priority	=	100,
1204 };
1205 
1206 static struct xfrm6_protocol vti_ah6_protocol __read_mostly = {
1207 	.handler	=	vti6_rcv,
1208 	.input_handler	=	vti6_input_proto,
1209 	.cb_handler	=	vti6_rcv_cb,
1210 	.err_handler	=	vti6_err,
1211 	.priority	=	100,
1212 };
1213 
1214 static struct xfrm6_protocol vti_ipcomp6_protocol __read_mostly = {
1215 	.handler	=	vti6_rcv,
1216 	.input_handler	=	vti6_input_proto,
1217 	.cb_handler	=	vti6_rcv_cb,
1218 	.err_handler	=	vti6_err,
1219 	.priority	=	100,
1220 };
1221 
1222 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1223 static int vti6_rcv_tunnel(struct sk_buff *skb)
1224 {
1225 	const xfrm_address_t *saddr;
1226 	__be32 spi;
1227 
1228 	saddr = (const xfrm_address_t *)&ipv6_hdr(skb)->saddr;
1229 	spi = xfrm6_tunnel_spi_lookup(dev_net(skb->dev), saddr);
1230 
1231 	return vti6_input_proto(skb, IPPROTO_IPV6, spi, 0);
1232 }
1233 
1234 static struct xfrm6_tunnel vti_ipv6_handler __read_mostly = {
1235 	.handler	=	vti6_rcv_tunnel,
1236 	.cb_handler	=	vti6_rcv_cb,
1237 	.err_handler	=	vti6_err,
1238 	.priority	=	0,
1239 };
1240 
1241 static struct xfrm6_tunnel vti_ip6ip_handler __read_mostly = {
1242 	.handler	=	vti6_rcv_tunnel,
1243 	.cb_handler	=	vti6_rcv_cb,
1244 	.err_handler	=	vti6_err,
1245 	.priority	=	0,
1246 };
1247 #endif
1248 
1249 /**
1250  * vti6_tunnel_init - register protocol and reserve needed resources
1251  *
1252  * Return: 0 on success
1253  **/
1254 static int __init vti6_tunnel_init(void)
1255 {
1256 	const char *msg;
1257 	int err;
1258 
1259 	msg = "tunnel device";
1260 	err = register_pernet_device(&vti6_net_ops);
1261 	if (err < 0)
1262 		goto pernet_dev_failed;
1263 
1264 	msg = "tunnel protocols";
1265 	err = xfrm6_protocol_register(&vti_esp6_protocol, IPPROTO_ESP);
1266 	if (err < 0)
1267 		goto xfrm_proto_esp_failed;
1268 	err = xfrm6_protocol_register(&vti_ah6_protocol, IPPROTO_AH);
1269 	if (err < 0)
1270 		goto xfrm_proto_ah_failed;
1271 	err = xfrm6_protocol_register(&vti_ipcomp6_protocol, IPPROTO_COMP);
1272 	if (err < 0)
1273 		goto xfrm_proto_comp_failed;
1274 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1275 	msg = "ipv6 tunnel";
1276 	err = xfrm6_tunnel_register(&vti_ipv6_handler, AF_INET6);
1277 	if (err < 0)
1278 		goto vti_tunnel_ipv6_failed;
1279 	err = xfrm6_tunnel_register(&vti_ip6ip_handler, AF_INET);
1280 	if (err < 0)
1281 		goto vti_tunnel_ip6ip_failed;
1282 #endif
1283 
1284 	msg = "netlink interface";
1285 	err = rtnl_link_register(&vti6_link_ops);
1286 	if (err < 0)
1287 		goto rtnl_link_failed;
1288 
1289 	return 0;
1290 
1291 rtnl_link_failed:
1292 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1293 	err = xfrm6_tunnel_deregister(&vti_ip6ip_handler, AF_INET);
1294 vti_tunnel_ip6ip_failed:
1295 	err = xfrm6_tunnel_deregister(&vti_ipv6_handler, AF_INET6);
1296 vti_tunnel_ipv6_failed:
1297 #endif
1298 	xfrm6_protocol_deregister(&vti_ipcomp6_protocol, IPPROTO_COMP);
1299 xfrm_proto_comp_failed:
1300 	xfrm6_protocol_deregister(&vti_ah6_protocol, IPPROTO_AH);
1301 xfrm_proto_ah_failed:
1302 	xfrm6_protocol_deregister(&vti_esp6_protocol, IPPROTO_ESP);
1303 xfrm_proto_esp_failed:
1304 	unregister_pernet_device(&vti6_net_ops);
1305 pernet_dev_failed:
1306 	pr_err("vti6 init: failed to register %s\n", msg);
1307 	return err;
1308 }
1309 
1310 /**
1311  * vti6_tunnel_cleanup - free resources and unregister protocol
1312  **/
1313 static void __exit vti6_tunnel_cleanup(void)
1314 {
1315 	rtnl_link_unregister(&vti6_link_ops);
1316 #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)
1317 	xfrm6_tunnel_deregister(&vti_ip6ip_handler, AF_INET);
1318 	xfrm6_tunnel_deregister(&vti_ipv6_handler, AF_INET6);
1319 #endif
1320 	xfrm6_protocol_deregister(&vti_ipcomp6_protocol, IPPROTO_COMP);
1321 	xfrm6_protocol_deregister(&vti_ah6_protocol, IPPROTO_AH);
1322 	xfrm6_protocol_deregister(&vti_esp6_protocol, IPPROTO_ESP);
1323 	unregister_pernet_device(&vti6_net_ops);
1324 }
1325 
1326 module_init(vti6_tunnel_init);
1327 module_exit(vti6_tunnel_cleanup);
1328 MODULE_LICENSE("GPL");
1329 MODULE_ALIAS_RTNL_LINK("vti6");
1330 MODULE_ALIAS_NETDEV("ip6_vti0");
1331 MODULE_AUTHOR("Steffen Klassert");
1332 MODULE_DESCRIPTION("IPv6 virtual tunnel interface");
1333