xref: /openbmc/linux/net/ipv4/ip_vti.c (revision f3a8b664) 
1 /*
2  *	Linux NET3: IP/IP protocol decoder modified to support
3  *		    virtual tunnel interface
4  *
5  *	Authors:
6  *		Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
7  *
8  *	This program is free software; you can redistribute it and/or
9  *	modify it under the terms of the GNU General Public License
10  *	as published by the Free Software Foundation; either version
11  *	2 of the License, or (at your option) any later version.
12  *
13  */
14 
15 /*
16    This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
17 
18    For comments look at net/ipv4/ip_gre.c --ANK
19  */
20 
21 
22 #include <linux/capability.h>
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include <linux/kernel.h>
26 #include <linux/uaccess.h>
27 #include <linux/skbuff.h>
28 #include <linux/netdevice.h>
29 #include <linux/in.h>
30 #include <linux/tcp.h>
31 #include <linux/udp.h>
32 #include <linux/if_arp.h>
33 #include <linux/init.h>
34 #include <linux/netfilter_ipv4.h>
35 #include <linux/if_ether.h>
36 #include <linux/icmpv6.h>
37 
38 #include <net/sock.h>
39 #include <net/ip.h>
40 #include <net/icmp.h>
41 #include <net/ip_tunnels.h>
42 #include <net/inet_ecn.h>
43 #include <net/xfrm.h>
44 #include <net/net_namespace.h>
45 #include <net/netns/generic.h>
46 
47 static struct rtnl_link_ops vti_link_ops __read_mostly;
48 
49 static int vti_net_id __read_mostly;
50 static int vti_tunnel_init(struct net_device *dev);
51 
52 static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi,
53 		     int encap_type)
54 {
55 	struct ip_tunnel *tunnel;
56 	const struct iphdr *iph = ip_hdr(skb);
57 	struct net *net = dev_net(skb->dev);
58 	struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
59 
60 	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
61 				  iph->saddr, iph->daddr, 0);
62 	if (tunnel) {
63 		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
64 			goto drop;
65 
66 		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
67 
68 		return xfrm_input(skb, nexthdr, spi, encap_type);
69 	}
70 
71 	return -EINVAL;
72 drop:
73 	kfree_skb(skb);
74 	return 0;
75 }
76 
77 static int vti_rcv(struct sk_buff *skb)
78 {
79 	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
80 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
81 
82 	return vti_input(skb, ip_hdr(skb)->protocol, 0, 0);
83 }
84 
85 static int vti_rcv_cb(struct sk_buff *skb, int err)
86 {
87 	unsigned short family;
88 	struct net_device *dev;
89 	struct pcpu_sw_netstats *tstats;
90 	struct xfrm_state *x;
91 	struct xfrm_mode *inner_mode;
92 	struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
93 	u32 orig_mark = skb->mark;
94 	int ret;
95 
96 	if (!tunnel)
97 		return 1;
98 
99 	dev = tunnel->dev;
100 
101 	if (err) {
102 		dev->stats.rx_errors++;
103 		dev->stats.rx_dropped++;
104 
105 		return 0;
106 	}
107 
108 	x = xfrm_input_state(skb);
109 
110 	inner_mode = x->inner_mode;
111 
112 	if (x->sel.family == AF_UNSPEC) {
113 		inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
114 		if (inner_mode == NULL) {
115 			XFRM_INC_STATS(dev_net(skb->dev),
116 				       LINUX_MIB_XFRMINSTATEMODEERROR);
117 			return -EINVAL;
118 		}
119 	}
120 
121 	family = inner_mode->afinfo->family;
122 
123 	skb->mark = be32_to_cpu(tunnel->parms.i_key);
124 	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
125 	skb->mark = orig_mark;
126 
127 	if (!ret)
128 		return -EPERM;
129 
130 	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
131 	skb->dev = dev;
132 
133 	tstats = this_cpu_ptr(dev->tstats);
134 
135 	u64_stats_update_begin(&tstats->syncp);
136 	tstats->rx_packets++;
137 	tstats->rx_bytes += skb->len;
138 	u64_stats_update_end(&tstats->syncp);
139 
140 	return 0;
141 }
142 
143 static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
144 {
145 	xfrm_address_t *daddr = (xfrm_address_t *)&dst;
146 	xfrm_address_t *saddr = (xfrm_address_t *)&src;
147 
148 	/* if there is no transform then this tunnel is not functional.
149 	 * Or if the xfrm is not mode tunnel.
150 	 */
151 	if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
152 	    x->props.family != AF_INET)
153 		return false;
154 
155 	if (!dst)
156 		return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
157 
158 	if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
159 		return false;
160 
161 	return true;
162 }
163 
164 static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
165 			    struct flowi *fl)
166 {
167 	struct ip_tunnel *tunnel = netdev_priv(dev);
168 	struct ip_tunnel_parm *parms = &tunnel->parms;
169 	struct dst_entry *dst = skb_dst(skb);
170 	struct net_device *tdev;	/* Device to other host */
171 	int err;
172 	int mtu;
173 
174 	if (!dst) {
175 		dev->stats.tx_carrier_errors++;
176 		goto tx_error_icmp;
177 	}
178 
179 	dst_hold(dst);
180 	dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0);
181 	if (IS_ERR(dst)) {
182 		dev->stats.tx_carrier_errors++;
183 		goto tx_error_icmp;
184 	}
185 
186 	if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
187 		dev->stats.tx_carrier_errors++;
188 		dst_release(dst);
189 		goto tx_error_icmp;
190 	}
191 
192 	tdev = dst->dev;
193 
194 	if (tdev == dev) {
195 		dst_release(dst);
196 		dev->stats.collisions++;
197 		goto tx_error;
198 	}
199 
200 	if (tunnel->err_count > 0) {
201 		if (time_before(jiffies,
202 				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
203 			tunnel->err_count--;
204 			dst_link_failure(skb);
205 		} else
206 			tunnel->err_count = 0;
207 	}
208 
209 	mtu = dst_mtu(dst);
210 	if (skb->len > mtu) {
211 		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
212 		if (skb->protocol == htons(ETH_P_IP)) {
213 			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
214 				  htonl(mtu));
215 		} else {
216 			if (mtu < IPV6_MIN_MTU)
217 				mtu = IPV6_MIN_MTU;
218 
219 			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
220 		}
221 
222 		dst_release(dst);
223 		goto tx_error;
224 	}
225 
226 	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
227 	skb_dst_set(skb, dst);
228 	skb->dev = skb_dst(skb)->dev;
229 
230 	err = dst_output(tunnel->net, skb->sk, skb);
231 	if (net_xmit_eval(err) == 0)
232 		err = skb->len;
233 	iptunnel_xmit_stats(dev, err);
234 	return NETDEV_TX_OK;
235 
236 tx_error_icmp:
237 	dst_link_failure(skb);
238 tx_error:
239 	dev->stats.tx_errors++;
240 	kfree_skb(skb);
241 	return NETDEV_TX_OK;
242 }
243 
244 /* This function assumes it is being called from dev_queue_xmit()
245  * and that skb is filled properly by that function.
246  */
247 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
248 {
249 	struct ip_tunnel *tunnel = netdev_priv(dev);
250 	struct flowi fl;
251 
252 	memset(&fl, 0, sizeof(fl));
253 
254 	switch (skb->protocol) {
255 	case htons(ETH_P_IP):
256 		xfrm_decode_session(skb, &fl, AF_INET);
257 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
258 		break;
259 	case htons(ETH_P_IPV6):
260 		xfrm_decode_session(skb, &fl, AF_INET6);
261 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
262 		break;
263 	default:
264 		dev->stats.tx_errors++;
265 		dev_kfree_skb(skb);
266 		return NETDEV_TX_OK;
267 	}
268 
269 	/* override mark with tunnel output key */
270 	fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
271 
272 	return vti_xmit(skb, dev, &fl);
273 }
274 
275 static int vti4_err(struct sk_buff *skb, u32 info)
276 {
277 	__be32 spi;
278 	__u32 mark;
279 	struct xfrm_state *x;
280 	struct ip_tunnel *tunnel;
281 	struct ip_esp_hdr *esph;
282 	struct ip_auth_hdr *ah ;
283 	struct ip_comp_hdr *ipch;
284 	struct net *net = dev_net(skb->dev);
285 	const struct iphdr *iph = (const struct iphdr *)skb->data;
286 	int protocol = iph->protocol;
287 	struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
288 
289 	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
290 				  iph->daddr, iph->saddr, 0);
291 	if (!tunnel)
292 		return -1;
293 
294 	mark = be32_to_cpu(tunnel->parms.o_key);
295 
296 	switch (protocol) {
297 	case IPPROTO_ESP:
298 		esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
299 		spi = esph->spi;
300 		break;
301 	case IPPROTO_AH:
302 		ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
303 		spi = ah->spi;
304 		break;
305 	case IPPROTO_COMP:
306 		ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
307 		spi = htonl(ntohs(ipch->cpi));
308 		break;
309 	default:
310 		return 0;
311 	}
312 
313 	switch (icmp_hdr(skb)->type) {
314 	case ICMP_DEST_UNREACH:
315 		if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
316 			return 0;
317 	case ICMP_REDIRECT:
318 		break;
319 	default:
320 		return 0;
321 	}
322 
323 	x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
324 			      spi, protocol, AF_INET);
325 	if (!x)
326 		return 0;
327 
328 	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
329 		ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0);
330 	else
331 		ipv4_redirect(skb, net, 0, 0, protocol, 0);
332 	xfrm_state_put(x);
333 
334 	return 0;
335 }
336 
337 static int
338 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
339 {
340 	int err = 0;
341 	struct ip_tunnel_parm p;
342 
343 	if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
344 		return -EFAULT;
345 
346 	if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
347 		if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
348 		    p.iph.ihl != 5)
349 			return -EINVAL;
350 	}
351 
352 	if (!(p.i_flags & GRE_KEY))
353 		p.i_key = 0;
354 	if (!(p.o_flags & GRE_KEY))
355 		p.o_key = 0;
356 
357 	p.i_flags = VTI_ISVTI;
358 
359 	err = ip_tunnel_ioctl(dev, &p, cmd);
360 	if (err)
361 		return err;
362 
363 	if (cmd != SIOCDELTUNNEL) {
364 		p.i_flags |= GRE_KEY;
365 		p.o_flags |= GRE_KEY;
366 	}
367 
368 	if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
369 		return -EFAULT;
370 	return 0;
371 }
372 
373 static const struct net_device_ops vti_netdev_ops = {
374 	.ndo_init	= vti_tunnel_init,
375 	.ndo_uninit	= ip_tunnel_uninit,
376 	.ndo_start_xmit	= vti_tunnel_xmit,
377 	.ndo_do_ioctl	= vti_tunnel_ioctl,
378 	.ndo_change_mtu	= ip_tunnel_change_mtu,
379 	.ndo_get_stats64 = ip_tunnel_get_stats64,
380 	.ndo_get_iflink = ip_tunnel_get_iflink,
381 };
382 
383 static void vti_tunnel_setup(struct net_device *dev)
384 {
385 	dev->netdev_ops		= &vti_netdev_ops;
386 	dev->type		= ARPHRD_TUNNEL;
387 	ip_tunnel_setup(dev, vti_net_id);
388 }
389 
390 static int vti_tunnel_init(struct net_device *dev)
391 {
392 	struct ip_tunnel *tunnel = netdev_priv(dev);
393 	struct iphdr *iph = &tunnel->parms.iph;
394 
395 	memcpy(dev->dev_addr, &iph->saddr, 4);
396 	memcpy(dev->broadcast, &iph->daddr, 4);
397 
398 	dev->hard_header_len	= LL_MAX_HEADER + sizeof(struct iphdr);
399 	dev->mtu		= ETH_DATA_LEN;
400 	dev->flags		= IFF_NOARP;
401 	dev->addr_len		= 4;
402 	dev->features		|= NETIF_F_LLTX;
403 	netif_keep_dst(dev);
404 
405 	return ip_tunnel_init(dev);
406 }
407 
408 static void __net_init vti_fb_tunnel_init(struct net_device *dev)
409 {
410 	struct ip_tunnel *tunnel = netdev_priv(dev);
411 	struct iphdr *iph = &tunnel->parms.iph;
412 
413 	iph->version		= 4;
414 	iph->protocol		= IPPROTO_IPIP;
415 	iph->ihl		= 5;
416 }
417 
418 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
419 	.handler	=	vti_rcv,
420 	.input_handler	=	vti_input,
421 	.cb_handler	=	vti_rcv_cb,
422 	.err_handler	=	vti4_err,
423 	.priority	=	100,
424 };
425 
426 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
427 	.handler	=	vti_rcv,
428 	.input_handler	=	vti_input,
429 	.cb_handler	=	vti_rcv_cb,
430 	.err_handler	=	vti4_err,
431 	.priority	=	100,
432 };
433 
434 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
435 	.handler	=	vti_rcv,
436 	.input_handler	=	vti_input,
437 	.cb_handler	=	vti_rcv_cb,
438 	.err_handler	=	vti4_err,
439 	.priority	=	100,
440 };
441 
442 static int __net_init vti_init_net(struct net *net)
443 {
444 	int err;
445 	struct ip_tunnel_net *itn;
446 
447 	err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
448 	if (err)
449 		return err;
450 	itn = net_generic(net, vti_net_id);
451 	vti_fb_tunnel_init(itn->fb_tunnel_dev);
452 	return 0;
453 }
454 
455 static void __net_exit vti_exit_net(struct net *net)
456 {
457 	struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
458 	ip_tunnel_delete_net(itn, &vti_link_ops);
459 }
460 
461 static struct pernet_operations vti_net_ops = {
462 	.init = vti_init_net,
463 	.exit = vti_exit_net,
464 	.id   = &vti_net_id,
465 	.size = sizeof(struct ip_tunnel_net),
466 };
467 
468 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
469 {
470 	return 0;
471 }
472 
473 static void vti_netlink_parms(struct nlattr *data[],
474 			      struct ip_tunnel_parm *parms)
475 {
476 	memset(parms, 0, sizeof(*parms));
477 
478 	parms->iph.protocol = IPPROTO_IPIP;
479 
480 	if (!data)
481 		return;
482 
483 	parms->i_flags = VTI_ISVTI;
484 
485 	if (data[IFLA_VTI_LINK])
486 		parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
487 
488 	if (data[IFLA_VTI_IKEY])
489 		parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
490 
491 	if (data[IFLA_VTI_OKEY])
492 		parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
493 
494 	if (data[IFLA_VTI_LOCAL])
495 		parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]);
496 
497 	if (data[IFLA_VTI_REMOTE])
498 		parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]);
499 
500 }
501 
502 static int vti_newlink(struct net *src_net, struct net_device *dev,
503 		       struct nlattr *tb[], struct nlattr *data[])
504 {
505 	struct ip_tunnel_parm parms;
506 
507 	vti_netlink_parms(data, &parms);
508 	return ip_tunnel_newlink(dev, tb, &parms);
509 }
510 
511 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
512 			  struct nlattr *data[])
513 {
514 	struct ip_tunnel_parm p;
515 
516 	vti_netlink_parms(data, &p);
517 	return ip_tunnel_changelink(dev, tb, &p);
518 }
519 
520 static size_t vti_get_size(const struct net_device *dev)
521 {
522 	return
523 		/* IFLA_VTI_LINK */
524 		nla_total_size(4) +
525 		/* IFLA_VTI_IKEY */
526 		nla_total_size(4) +
527 		/* IFLA_VTI_OKEY */
528 		nla_total_size(4) +
529 		/* IFLA_VTI_LOCAL */
530 		nla_total_size(4) +
531 		/* IFLA_VTI_REMOTE */
532 		nla_total_size(4) +
533 		0;
534 }
535 
536 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
537 {
538 	struct ip_tunnel *t = netdev_priv(dev);
539 	struct ip_tunnel_parm *p = &t->parms;
540 
541 	nla_put_u32(skb, IFLA_VTI_LINK, p->link);
542 	nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
543 	nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
544 	nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr);
545 	nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr);
546 
547 	return 0;
548 }
549 
550 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
551 	[IFLA_VTI_LINK]		= { .type = NLA_U32 },
552 	[IFLA_VTI_IKEY]		= { .type = NLA_U32 },
553 	[IFLA_VTI_OKEY]		= { .type = NLA_U32 },
554 	[IFLA_VTI_LOCAL]	= { .len = FIELD_SIZEOF(struct iphdr, saddr) },
555 	[IFLA_VTI_REMOTE]	= { .len = FIELD_SIZEOF(struct iphdr, daddr) },
556 };
557 
558 static struct rtnl_link_ops vti_link_ops __read_mostly = {
559 	.kind		= "vti",
560 	.maxtype	= IFLA_VTI_MAX,
561 	.policy		= vti_policy,
562 	.priv_size	= sizeof(struct ip_tunnel),
563 	.setup		= vti_tunnel_setup,
564 	.validate	= vti_tunnel_validate,
565 	.newlink	= vti_newlink,
566 	.changelink	= vti_changelink,
567 	.dellink        = ip_tunnel_dellink,
568 	.get_size	= vti_get_size,
569 	.fill_info	= vti_fill_info,
570 	.get_link_net	= ip_tunnel_get_link_net,
571 };
572 
573 static bool is_vti_tunnel(const struct net_device *dev)
574 {
575 	return dev->netdev_ops == &vti_netdev_ops;
576 }
577 
578 static int vti_device_event(struct notifier_block *unused,
579 			    unsigned long event, void *ptr)
580 {
581 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
582 	struct ip_tunnel *tunnel = netdev_priv(dev);
583 
584 	if (!is_vti_tunnel(dev))
585 		return NOTIFY_DONE;
586 
587 	switch (event) {
588 	case NETDEV_DOWN:
589 		if (!net_eq(tunnel->net, dev_net(dev)))
590 			xfrm_garbage_collect(tunnel->net);
591 		break;
592 	}
593 	return NOTIFY_DONE;
594 }
595 
596 static struct notifier_block vti_notifier_block __read_mostly = {
597 	.notifier_call = vti_device_event,
598 };
599 
600 static int __init vti_init(void)
601 {
602 	const char *msg;
603 	int err;
604 
605 	pr_info("IPv4 over IPsec tunneling driver\n");
606 
607 	register_netdevice_notifier(&vti_notifier_block);
608 
609 	msg = "tunnel device";
610 	err = register_pernet_device(&vti_net_ops);
611 	if (err < 0)
612 		goto pernet_dev_failed;
613 
614 	msg = "tunnel protocols";
615 	err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
616 	if (err < 0)
617 		goto xfrm_proto_esp_failed;
618 	err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
619 	if (err < 0)
620 		goto xfrm_proto_ah_failed;
621 	err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
622 	if (err < 0)
623 		goto xfrm_proto_comp_failed;
624 
625 	msg = "netlink interface";
626 	err = rtnl_link_register(&vti_link_ops);
627 	if (err < 0)
628 		goto rtnl_link_failed;
629 
630 	return err;
631 
632 rtnl_link_failed:
633 	xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
634 xfrm_proto_comp_failed:
635 	xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
636 xfrm_proto_ah_failed:
637 	xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
638 xfrm_proto_esp_failed:
639 	unregister_pernet_device(&vti_net_ops);
640 pernet_dev_failed:
641 	unregister_netdevice_notifier(&vti_notifier_block);
642 	pr_err("vti init: failed to register %s\n", msg);
643 	return err;
644 }
645 
646 static void __exit vti_fini(void)
647 {
648 	rtnl_link_unregister(&vti_link_ops);
649 	xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
650 	xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
651 	xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
652 	unregister_pernet_device(&vti_net_ops);
653 	unregister_netdevice_notifier(&vti_notifier_block);
654 }
655 
656 module_init(vti_init);
657 module_exit(vti_fini);
658 MODULE_LICENSE("GPL");
659 MODULE_ALIAS_RTNL_LINK("vti");
660 MODULE_ALIAS_NETDEV("ip_vti0");
661