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1/*
2 * Linux NET3: IP/IP protocol decoder.
3 *
4 * Authors:
5 * Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95
6 *
7 * Fixes:
8 * Alan Cox : Merged and made usable non modular (its so tiny its silly as
9 * a module taking up 2 pages).
10 * Alan Cox : Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph)
11 * to keep ip_forward happy.
12 * Alan Cox : More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8).
13 * Kai Schulte : Fixed #defines for IP_FIREWALL->FIREWALL
14 * David Woodhouse : Perform some basic ICMP handling.
15 * IPIP Routing without decapsulation.
16 * Carlos Picoto : GRE over IP support
17 * Alexey Kuznetsov: Reworked. Really, now it is truncated version of ipv4/ip_gre.c.
18 * I do not want to merge them together.
19 *
20 * This program is free software; you can redistribute it and/or
21 * modify it under the terms of the GNU General Public License
22 * as published by the Free Software Foundation; either version
23 * 2 of the License, or (at your option) any later version.
24 *
25 */
26
27/* tunnel.c: an IP tunnel driver
28
29 The purpose of this driver is to provide an IP tunnel through
30 which you can tunnel network traffic transparently across subnets.
31
32 This was written by looking at Nick Holloway's dummy driver
33 Thanks for the great code!
34
35 -Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95
36
37 Minor tweaks:
38 Cleaned up the code a little and added some pre-1.3.0 tweaks.
39 dev->hard_header/hard_header_len changed to use no headers.
40 Comments/bracketing tweaked.
41 Made the tunnels use dev->name not tunnel: when error reporting.
42 Added tx_dropped stat
43
44 -Alan Cox (alan@lxorguk.ukuu.org.uk) 21 March 95
45
46 Reworked:
47 Changed to tunnel to destination gateway in addition to the
48 tunnel's pointopoint address
49 Almost completely rewritten
50 Note: There is currently no firewall or ICMP handling done.
51
52 -Sam Lantinga (slouken@cs.ucdavis.edu) 02/13/96
53
54*/
55
56/* Things I wish I had known when writing the tunnel driver:
57
58 When the tunnel_xmit() function is called, the skb contains the
59 packet to be sent (plus a great deal of extra info), and dev
60 contains the tunnel device that _we_ are.
61
62 When we are passed a packet, we are expected to fill in the
63 source address with our source IP address.
64
65 What is the proper way to allocate, copy and free a buffer?
66 After you allocate it, it is a "0 length" chunk of memory
67 starting at zero. If you want to add headers to the buffer
68 later, you'll have to call "skb_reserve(skb, amount)" with
69 the amount of memory you want reserved. Then, you call
70 "skb_put(skb, amount)" with the amount of space you want in
71 the buffer. skb_put() returns a pointer to the top (#0) of
72 that buffer. skb->len is set to the amount of space you have
73 "allocated" with skb_put(). You can then write up to skb->len
74 bytes to that buffer. If you need more, you can call skb_put()
75 again with the additional amount of space you need. You can
76 find out how much more space you can allocate by calling
77 "skb_tailroom(skb)".
78 Now, to add header space, call "skb_push(skb, header_len)".
79 This creates space at the beginning of the buffer and returns
80 a pointer to this new space. If later you need to strip a
81 header from a buffer, call "skb_pull(skb, header_len)".
82 skb_headroom() will return how much space is left at the top
83 of the buffer (before the main data). Remember, this headroom
84 space must be reserved before the skb_put() function is called.
85 */
86
87/*
88 This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c
89
90 For comments look at net/ipv4/ip_gre.c --ANK
91 */
92
93
94#include <linux/capability.h>
95#include <linux/module.h>
96#include <linux/types.h>
97#include <linux/kernel.h>
98#include <linux/slab.h>
99#include <asm/uaccess.h>
100#include <linux/skbuff.h>
101#include <linux/netdevice.h>
102#include <linux/in.h>
103#include <linux/tcp.h>
104#include <linux/udp.h>
105#include <linux/if_arp.h>
106#include <linux/init.h>
107#include <linux/netfilter_ipv4.h>
108#include <linux/if_ether.h>
109
110#include <net/sock.h>
111#include <net/ip.h>
112#include <net/icmp.h>
113#include <net/ip_tunnels.h>
114#include <net/inet_ecn.h>
115#include <net/xfrm.h>
116#include <net/net_namespace.h>
117#include <net/netns/generic.h>
118
119static bool log_ecn_error = true;
120module_param(log_ecn_error, bool, 0644);
121MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
122
123static int ipip_net_id __read_mostly;
124
125static int ipip_tunnel_init(struct net_device *dev);
126static struct rtnl_link_ops ipip_link_ops __read_mostly;
127
128static int ipip_err(struct sk_buff *skb, u32 info)
129{
130
131/* All the routers (except for Linux) return only
132 8 bytes of packet payload. It means, that precise relaying of
133 ICMP in the real Internet is absolutely infeasible.
134 */
135 struct net *net = dev_net(skb->dev);
136 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
137 const struct iphdr *iph = (const struct iphdr *)skb->data;
138 struct ip_tunnel *t;
139 int err;
140 const int type = icmp_hdr(skb)->type;
141 const int code = icmp_hdr(skb)->code;
142
143 err = -ENOENT;
144 t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
145 iph->daddr, iph->saddr, 0);
146 if (!t)
147 goto out;
148
149 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
150 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
151 t->parms.link, 0, IPPROTO_IPIP, 0);
152 err = 0;
153 goto out;
154 }
155
156 if (type == ICMP_REDIRECT) {
157 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
158 IPPROTO_IPIP, 0);
159 err = 0;
160 goto out;
161 }
162
163 if (t->parms.iph.daddr == 0)
164 goto out;
165
166 err = 0;
167 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
168 goto out;
169
170 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
171 t->err_count++;
172 else
173 t->err_count = 1;
174 t->err_time = jiffies;
175
176out:
177 return err;
178}
179
180static const struct tnl_ptk_info tpi = {
181 /* no tunnel info required for ipip. */
182 .proto = htons(ETH_P_IP),
183};
184
185static int ipip_rcv(struct sk_buff *skb)
186{
187 struct net *net = dev_net(skb->dev);
188 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
189 struct ip_tunnel *tunnel;
190 const struct iphdr *iph;
191
192 iph = ip_hdr(skb);
193 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
194 iph->saddr, iph->daddr, 0);
195 if (tunnel) {
196 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
197 goto drop;
198 if (iptunnel_pull_header(skb, 0, tpi.proto, false))
199 goto drop;
200 return ip_tunnel_rcv(tunnel, skb, &tpi, NULL, log_ecn_error);
201 }
202
203 return -1;
204
205drop:
206 kfree_skb(skb);
207 return 0;
208}
209
210/*
211 * This function assumes it is being called from dev_queue_xmit()
212 * and that skb is filled properly by that function.
213 */
214static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
215{
216 struct ip_tunnel *tunnel = netdev_priv(dev);
217 const struct iphdr *tiph = &tunnel->parms.iph;
218
219 if (unlikely(skb->protocol != htons(ETH_P_IP)))
220 goto tx_error;
221
222 skb = iptunnel_handle_offloads(skb, SKB_GSO_IPIP);
223 if (IS_ERR(skb))
224 goto out;
225
226 skb_set_inner_ipproto(skb, IPPROTO_IPIP);
227
228 ip_tunnel_xmit(skb, dev, tiph, tiph->protocol);
229 return NETDEV_TX_OK;
230
231tx_error:
232 kfree_skb(skb);
233out:
234 dev->stats.tx_errors++;
235 return NETDEV_TX_OK;
236}
237
238static int
239ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
240{
241 int err = 0;
242 struct ip_tunnel_parm p;
243
244 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
245 return -EFAULT;
246
247 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
248 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
249 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
250 return -EINVAL;
251 }
252
253 p.i_key = p.o_key = 0;
254 p.i_flags = p.o_flags = 0;
255 err = ip_tunnel_ioctl(dev, &p, cmd);
256 if (err)
257 return err;
258
259 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
260 return -EFAULT;
261
262 return 0;
263}
264
265static const struct net_device_ops ipip_netdev_ops = {
266 .ndo_init = ipip_tunnel_init,
267 .ndo_uninit = ip_tunnel_uninit,
268 .ndo_start_xmit = ipip_tunnel_xmit,
269 .ndo_do_ioctl = ipip_tunnel_ioctl,
270 .ndo_change_mtu = ip_tunnel_change_mtu,
271 .ndo_get_stats64 = ip_tunnel_get_stats64,
272 .ndo_get_iflink = ip_tunnel_get_iflink,
273};
274
275#define IPIP_FEATURES (NETIF_F_SG | \
276 NETIF_F_FRAGLIST | \
277 NETIF_F_HIGHDMA | \
278 NETIF_F_GSO_SOFTWARE | \
279 NETIF_F_HW_CSUM)
280
281static void ipip_tunnel_setup(struct net_device *dev)
282{
283 dev->netdev_ops = &ipip_netdev_ops;
284
285 dev->type = ARPHRD_TUNNEL;
286 dev->flags = IFF_NOARP;
287 dev->addr_len = 4;
288 dev->features |= NETIF_F_LLTX;
289 netif_keep_dst(dev);
290
291 dev->features |= IPIP_FEATURES;
292 dev->hw_features |= IPIP_FEATURES;
293 ip_tunnel_setup(dev, ipip_net_id);
294}
295
296static int ipip_tunnel_init(struct net_device *dev)
297{
298 struct ip_tunnel *tunnel = netdev_priv(dev);
299
300 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
301 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
302
303 tunnel->tun_hlen = 0;
304 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
305 tunnel->parms.iph.protocol = IPPROTO_IPIP;
306 return ip_tunnel_init(dev);
307}
308
309static void ipip_netlink_parms(struct nlattr *data[],
310 struct ip_tunnel_parm *parms)
311{
312 memset(parms, 0, sizeof(*parms));
313
314 parms->iph.version = 4;
315 parms->iph.protocol = IPPROTO_IPIP;
316 parms->iph.ihl = 5;
317
318 if (!data)
319 return;
320
321 if (data[IFLA_IPTUN_LINK])
322 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
323
324 if (data[IFLA_IPTUN_LOCAL])
325 parms->iph.saddr = nla_get_in_addr(data[IFLA_IPTUN_LOCAL]);
326
327 if (data[IFLA_IPTUN_REMOTE])
328 parms->iph.daddr = nla_get_in_addr(data[IFLA_IPTUN_REMOTE]);
329
330 if (data[IFLA_IPTUN_TTL]) {
331 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
332 if (parms->iph.ttl)
333 parms->iph.frag_off = htons(IP_DF);
334 }
335
336 if (data[IFLA_IPTUN_TOS])
337 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
338
339 if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
340 parms->iph.frag_off = htons(IP_DF);
341}
342
343/* This function returns true when ENCAP attributes are present in the nl msg */
344static bool ipip_netlink_encap_parms(struct nlattr *data[],
345 struct ip_tunnel_encap *ipencap)
346{
347 bool ret = false;
348
349 memset(ipencap, 0, sizeof(*ipencap));
350
351 if (!data)
352 return ret;
353
354 if (data[IFLA_IPTUN_ENCAP_TYPE]) {
355 ret = true;
356 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
357 }
358
359 if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
360 ret = true;
361 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
362 }
363
364 if (data[IFLA_IPTUN_ENCAP_SPORT]) {
365 ret = true;
366 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
367 }
368
369 if (data[IFLA_IPTUN_ENCAP_DPORT]) {
370 ret = true;
371 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
372 }
373
374 return ret;
375}
376
377static int ipip_newlink(struct net *src_net, struct net_device *dev,
378 struct nlattr *tb[], struct nlattr *data[])
379{
380 struct ip_tunnel_parm p;
381 struct ip_tunnel_encap ipencap;
382
383 if (ipip_netlink_encap_parms(data, &ipencap)) {
384 struct ip_tunnel *t = netdev_priv(dev);
385 int err = ip_tunnel_encap_setup(t, &ipencap);
386
387 if (err < 0)
388 return err;
389 }
390
391 ipip_netlink_parms(data, &p);
392 return ip_tunnel_newlink(dev, tb, &p);
393}
394
395static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
396 struct nlattr *data[])
397{
398 struct ip_tunnel_parm p;
399 struct ip_tunnel_encap ipencap;
400
401 if (ipip_netlink_encap_parms(data, &ipencap)) {
402 struct ip_tunnel *t = netdev_priv(dev);
403 int err = ip_tunnel_encap_setup(t, &ipencap);
404
405 if (err < 0)
406 return err;
407 }
408
409 ipip_netlink_parms(data, &p);
410
411 if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
412 (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
413 return -EINVAL;
414
415 return ip_tunnel_changelink(dev, tb, &p);
416}
417
418static size_t ipip_get_size(const struct net_device *dev)
419{
420 return
421 /* IFLA_IPTUN_LINK */
422 nla_total_size(4) +
423 /* IFLA_IPTUN_LOCAL */
424 nla_total_size(4) +
425 /* IFLA_IPTUN_REMOTE */
426 nla_total_size(4) +
427 /* IFLA_IPTUN_TTL */
428 nla_total_size(1) +
429 /* IFLA_IPTUN_TOS */
430 nla_total_size(1) +
431 /* IFLA_IPTUN_PMTUDISC */
432 nla_total_size(1) +
433 /* IFLA_IPTUN_ENCAP_TYPE */
434 nla_total_size(2) +
435 /* IFLA_IPTUN_ENCAP_FLAGS */
436 nla_total_size(2) +
437 /* IFLA_IPTUN_ENCAP_SPORT */
438 nla_total_size(2) +
439 /* IFLA_IPTUN_ENCAP_DPORT */
440 nla_total_size(2) +
441 0;
442}
443
444static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev)
445{
446 struct ip_tunnel *tunnel = netdev_priv(dev);
447 struct ip_tunnel_parm *parm = &tunnel->parms;
448
449 if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
450 nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
451 nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
452 nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
453 nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
454 nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
455 !!(parm->iph.frag_off & htons(IP_DF))))
456 goto nla_put_failure;
457
458 if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
459 tunnel->encap.type) ||
460 nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
461 tunnel->encap.sport) ||
462 nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
463 tunnel->encap.dport) ||
464 nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
465 tunnel->encap.flags))
466 goto nla_put_failure;
467
468 return 0;
469
470nla_put_failure:
471 return -EMSGSIZE;
472}
473
474static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = {
475 [IFLA_IPTUN_LINK] = { .type = NLA_U32 },
476 [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 },
477 [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 },
478 [IFLA_IPTUN_TTL] = { .type = NLA_U8 },
479 [IFLA_IPTUN_TOS] = { .type = NLA_U8 },
480 [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 },
481 [IFLA_IPTUN_ENCAP_TYPE] = { .type = NLA_U16 },
482 [IFLA_IPTUN_ENCAP_FLAGS] = { .type = NLA_U16 },
483 [IFLA_IPTUN_ENCAP_SPORT] = { .type = NLA_U16 },
484 [IFLA_IPTUN_ENCAP_DPORT] = { .type = NLA_U16 },
485};
486
487static struct rtnl_link_ops ipip_link_ops __read_mostly = {
488 .kind = "ipip",
489 .maxtype = IFLA_IPTUN_MAX,
490 .policy = ipip_policy,
491 .priv_size = sizeof(struct ip_tunnel),
492 .setup = ipip_tunnel_setup,
493 .newlink = ipip_newlink,
494 .changelink = ipip_changelink,
495 .dellink = ip_tunnel_dellink,
496 .get_size = ipip_get_size,
497 .fill_info = ipip_fill_info,
498 .get_link_net = ip_tunnel_get_link_net,
499};
500
501static struct xfrm_tunnel ipip_handler __read_mostly = {
502 .handler = ipip_rcv,
503 .err_handler = ipip_err,
504 .priority = 1,
505};
506
507static int __net_init ipip_init_net(struct net *net)
508{
509 return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0");
510}
511
512static void __net_exit ipip_exit_net(struct net *net)
513{
514 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
515 ip_tunnel_delete_net(itn, &ipip_link_ops);
516}
517
518static struct pernet_operations ipip_net_ops = {
519 .init = ipip_init_net,
520 .exit = ipip_exit_net,
521 .id = &ipip_net_id,
522 .size = sizeof(struct ip_tunnel_net),
523};
524
525static int __init ipip_init(void)
526{
527 int err;
528
529 pr_info("ipip: IPv4 over IPv4 tunneling driver\n");
530
531 err = register_pernet_device(&ipip_net_ops);
532 if (err < 0)
533 return err;
534 err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
535 if (err < 0) {
536 pr_info("%s: can't register tunnel\n", __func__);
537 goto xfrm_tunnel_failed;
538 }
539 err = rtnl_link_register(&ipip_link_ops);
540 if (err < 0)
541 goto rtnl_link_failed;
542
543out:
544 return err;
545
546rtnl_link_failed:
547 xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
548xfrm_tunnel_failed:
549 unregister_pernet_device(&ipip_net_ops);
550 goto out;
551}
552
553static void __exit ipip_fini(void)
554{
555 rtnl_link_unregister(&ipip_link_ops);
556 if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
557 pr_info("%s: can't deregister tunnel\n", __func__);
558
559 unregister_pernet_device(&ipip_net_ops);
560}
561
562module_init(ipip_init);
563module_exit(ipip_fini);
564MODULE_LICENSE("GPL");
565MODULE_ALIAS_RTNL_LINK("ipip");
566MODULE_ALIAS_NETDEV("tunl0");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Linux NET3: IP/IP protocol decoder.
4 *
5 * Authors:
6 * Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95
7 *
8 * Fixes:
9 * Alan Cox : Merged and made usable non modular (its so tiny its silly as
10 * a module taking up 2 pages).
11 * Alan Cox : Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph)
12 * to keep ip_forward happy.
13 * Alan Cox : More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8).
14 * Kai Schulte : Fixed #defines for IP_FIREWALL->FIREWALL
15 * David Woodhouse : Perform some basic ICMP handling.
16 * IPIP Routing without decapsulation.
17 * Carlos Picoto : GRE over IP support
18 * Alexey Kuznetsov: Reworked. Really, now it is truncated version of ipv4/ip_gre.c.
19 * I do not want to merge them together.
20 */
21
22/* tunnel.c: an IP tunnel driver
23
24 The purpose of this driver is to provide an IP tunnel through
25 which you can tunnel network traffic transparently across subnets.
26
27 This was written by looking at Nick Holloway's dummy driver
28 Thanks for the great code!
29
30 -Sam Lantinga (slouken@cs.ucdavis.edu) 02/01/95
31
32 Minor tweaks:
33 Cleaned up the code a little and added some pre-1.3.0 tweaks.
34 dev->hard_header/hard_header_len changed to use no headers.
35 Comments/bracketing tweaked.
36 Made the tunnels use dev->name not tunnel: when error reporting.
37 Added tx_dropped stat
38
39 -Alan Cox (alan@lxorguk.ukuu.org.uk) 21 March 95
40
41 Reworked:
42 Changed to tunnel to destination gateway in addition to the
43 tunnel's pointopoint address
44 Almost completely rewritten
45 Note: There is currently no firewall or ICMP handling done.
46
47 -Sam Lantinga (slouken@cs.ucdavis.edu) 02/13/96
48
49*/
50
51/* Things I wish I had known when writing the tunnel driver:
52
53 When the tunnel_xmit() function is called, the skb contains the
54 packet to be sent (plus a great deal of extra info), and dev
55 contains the tunnel device that _we_ are.
56
57 When we are passed a packet, we are expected to fill in the
58 source address with our source IP address.
59
60 What is the proper way to allocate, copy and free a buffer?
61 After you allocate it, it is a "0 length" chunk of memory
62 starting at zero. If you want to add headers to the buffer
63 later, you'll have to call "skb_reserve(skb, amount)" with
64 the amount of memory you want reserved. Then, you call
65 "skb_put(skb, amount)" with the amount of space you want in
66 the buffer. skb_put() returns a pointer to the top (#0) of
67 that buffer. skb->len is set to the amount of space you have
68 "allocated" with skb_put(). You can then write up to skb->len
69 bytes to that buffer. If you need more, you can call skb_put()
70 again with the additional amount of space you need. You can
71 find out how much more space you can allocate by calling
72 "skb_tailroom(skb)".
73 Now, to add header space, call "skb_push(skb, header_len)".
74 This creates space at the beginning of the buffer and returns
75 a pointer to this new space. If later you need to strip a
76 header from a buffer, call "skb_pull(skb, header_len)".
77 skb_headroom() will return how much space is left at the top
78 of the buffer (before the main data). Remember, this headroom
79 space must be reserved before the skb_put() function is called.
80 */
81
82/*
83 This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c
84
85 For comments look at net/ipv4/ip_gre.c --ANK
86 */
87
88
89#include <linux/capability.h>
90#include <linux/module.h>
91#include <linux/types.h>
92#include <linux/kernel.h>
93#include <linux/slab.h>
94#include <linux/uaccess.h>
95#include <linux/skbuff.h>
96#include <linux/netdevice.h>
97#include <linux/in.h>
98#include <linux/tcp.h>
99#include <linux/udp.h>
100#include <linux/if_arp.h>
101#include <linux/init.h>
102#include <linux/netfilter_ipv4.h>
103#include <linux/if_ether.h>
104
105#include <net/sock.h>
106#include <net/ip.h>
107#include <net/icmp.h>
108#include <net/ip_tunnels.h>
109#include <net/inet_ecn.h>
110#include <net/xfrm.h>
111#include <net/net_namespace.h>
112#include <net/netns/generic.h>
113#include <net/dst_metadata.h>
114
115static bool log_ecn_error = true;
116module_param(log_ecn_error, bool, 0644);
117MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
118
119static unsigned int ipip_net_id __read_mostly;
120
121static int ipip_tunnel_init(struct net_device *dev);
122static struct rtnl_link_ops ipip_link_ops __read_mostly;
123
124static int ipip_err(struct sk_buff *skb, u32 info)
125{
126 /* All the routers (except for Linux) return only
127 * 8 bytes of packet payload. It means, that precise relaying of
128 * ICMP in the real Internet is absolutely infeasible.
129 */
130 struct net *net = dev_net(skb->dev);
131 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
132 const struct iphdr *iph = (const struct iphdr *)skb->data;
133 const int type = icmp_hdr(skb)->type;
134 const int code = icmp_hdr(skb)->code;
135 struct ip_tunnel *t;
136 int err = 0;
137
138 t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
139 iph->daddr, iph->saddr, 0);
140 if (!t) {
141 err = -ENOENT;
142 goto out;
143 }
144
145 switch (type) {
146 case ICMP_DEST_UNREACH:
147 switch (code) {
148 case ICMP_SR_FAILED:
149 /* Impossible event. */
150 goto out;
151 default:
152 /* All others are translated to HOST_UNREACH.
153 * rfc2003 contains "deep thoughts" about NET_UNREACH,
154 * I believe they are just ether pollution. --ANK
155 */
156 break;
157 }
158 break;
159
160 case ICMP_TIME_EXCEEDED:
161 if (code != ICMP_EXC_TTL)
162 goto out;
163 break;
164
165 case ICMP_REDIRECT:
166 break;
167
168 default:
169 goto out;
170 }
171
172 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
173 ipv4_update_pmtu(skb, net, info, t->parms.link, iph->protocol);
174 goto out;
175 }
176
177 if (type == ICMP_REDIRECT) {
178 ipv4_redirect(skb, net, t->parms.link, iph->protocol);
179 goto out;
180 }
181
182 if (t->parms.iph.daddr == 0) {
183 err = -ENOENT;
184 goto out;
185 }
186
187 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
188 goto out;
189
190 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
191 t->err_count++;
192 else
193 t->err_count = 1;
194 t->err_time = jiffies;
195
196out:
197 return err;
198}
199
200static const struct tnl_ptk_info ipip_tpi = {
201 /* no tunnel info required for ipip. */
202 .proto = htons(ETH_P_IP),
203};
204
205#if IS_ENABLED(CONFIG_MPLS)
206static const struct tnl_ptk_info mplsip_tpi = {
207 /* no tunnel info required for mplsip. */
208 .proto = htons(ETH_P_MPLS_UC),
209};
210#endif
211
212static int ipip_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
213{
214 struct net *net = dev_net(skb->dev);
215 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
216 struct metadata_dst *tun_dst = NULL;
217 struct ip_tunnel *tunnel;
218 const struct iphdr *iph;
219
220 iph = ip_hdr(skb);
221 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
222 iph->saddr, iph->daddr, 0);
223 if (tunnel) {
224 const struct tnl_ptk_info *tpi;
225
226 if (tunnel->parms.iph.protocol != ipproto &&
227 tunnel->parms.iph.protocol != 0)
228 goto drop;
229
230 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
231 goto drop;
232#if IS_ENABLED(CONFIG_MPLS)
233 if (ipproto == IPPROTO_MPLS)
234 tpi = &mplsip_tpi;
235 else
236#endif
237 tpi = &ipip_tpi;
238 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
239 goto drop;
240 if (tunnel->collect_md) {
241 tun_dst = ip_tun_rx_dst(skb, 0, 0, 0);
242 if (!tun_dst)
243 return 0;
244 }
245 return ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
246 }
247
248 return -1;
249
250drop:
251 kfree_skb(skb);
252 return 0;
253}
254
255static int ipip_rcv(struct sk_buff *skb)
256{
257 return ipip_tunnel_rcv(skb, IPPROTO_IPIP);
258}
259
260#if IS_ENABLED(CONFIG_MPLS)
261static int mplsip_rcv(struct sk_buff *skb)
262{
263 return ipip_tunnel_rcv(skb, IPPROTO_MPLS);
264}
265#endif
266
267/*
268 * This function assumes it is being called from dev_queue_xmit()
269 * and that skb is filled properly by that function.
270 */
271static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb,
272 struct net_device *dev)
273{
274 struct ip_tunnel *tunnel = netdev_priv(dev);
275 const struct iphdr *tiph = &tunnel->parms.iph;
276 u8 ipproto;
277
278 if (!pskb_inet_may_pull(skb))
279 goto tx_error;
280
281 switch (skb->protocol) {
282 case htons(ETH_P_IP):
283 ipproto = IPPROTO_IPIP;
284 break;
285#if IS_ENABLED(CONFIG_MPLS)
286 case htons(ETH_P_MPLS_UC):
287 ipproto = IPPROTO_MPLS;
288 break;
289#endif
290 default:
291 goto tx_error;
292 }
293
294 if (tiph->protocol != ipproto && tiph->protocol != 0)
295 goto tx_error;
296
297 if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
298 goto tx_error;
299
300 skb_set_inner_ipproto(skb, ipproto);
301
302 if (tunnel->collect_md)
303 ip_md_tunnel_xmit(skb, dev, ipproto, 0);
304 else
305 ip_tunnel_xmit(skb, dev, tiph, ipproto);
306 return NETDEV_TX_OK;
307
308tx_error:
309 kfree_skb(skb);
310
311 dev->stats.tx_errors++;
312 return NETDEV_TX_OK;
313}
314
315static bool ipip_tunnel_ioctl_verify_protocol(u8 ipproto)
316{
317 switch (ipproto) {
318 case 0:
319 case IPPROTO_IPIP:
320#if IS_ENABLED(CONFIG_MPLS)
321 case IPPROTO_MPLS:
322#endif
323 return true;
324 }
325
326 return false;
327}
328
329static int
330ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
331{
332 int err = 0;
333 struct ip_tunnel_parm p;
334
335 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
336 return -EFAULT;
337
338 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
339 if (p.iph.version != 4 ||
340 !ipip_tunnel_ioctl_verify_protocol(p.iph.protocol) ||
341 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
342 return -EINVAL;
343 }
344
345 p.i_key = p.o_key = 0;
346 p.i_flags = p.o_flags = 0;
347 err = ip_tunnel_ioctl(dev, &p, cmd);
348 if (err)
349 return err;
350
351 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
352 return -EFAULT;
353
354 return 0;
355}
356
357static const struct net_device_ops ipip_netdev_ops = {
358 .ndo_init = ipip_tunnel_init,
359 .ndo_uninit = ip_tunnel_uninit,
360 .ndo_start_xmit = ipip_tunnel_xmit,
361 .ndo_do_ioctl = ipip_tunnel_ioctl,
362 .ndo_change_mtu = ip_tunnel_change_mtu,
363 .ndo_get_stats64 = ip_tunnel_get_stats64,
364 .ndo_get_iflink = ip_tunnel_get_iflink,
365};
366
367#define IPIP_FEATURES (NETIF_F_SG | \
368 NETIF_F_FRAGLIST | \
369 NETIF_F_HIGHDMA | \
370 NETIF_F_GSO_SOFTWARE | \
371 NETIF_F_HW_CSUM)
372
373static void ipip_tunnel_setup(struct net_device *dev)
374{
375 dev->netdev_ops = &ipip_netdev_ops;
376
377 dev->type = ARPHRD_TUNNEL;
378 dev->flags = IFF_NOARP;
379 dev->addr_len = 4;
380 dev->features |= NETIF_F_LLTX;
381 netif_keep_dst(dev);
382
383 dev->features |= IPIP_FEATURES;
384 dev->hw_features |= IPIP_FEATURES;
385 ip_tunnel_setup(dev, ipip_net_id);
386}
387
388static int ipip_tunnel_init(struct net_device *dev)
389{
390 struct ip_tunnel *tunnel = netdev_priv(dev);
391
392 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
393 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
394
395 tunnel->tun_hlen = 0;
396 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
397 return ip_tunnel_init(dev);
398}
399
400static int ipip_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
401 struct netlink_ext_ack *extack)
402{
403 u8 proto;
404
405 if (!data || !data[IFLA_IPTUN_PROTO])
406 return 0;
407
408 proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
409 if (proto != IPPROTO_IPIP && proto != IPPROTO_MPLS && proto != 0)
410 return -EINVAL;
411
412 return 0;
413}
414
415static void ipip_netlink_parms(struct nlattr *data[],
416 struct ip_tunnel_parm *parms, bool *collect_md,
417 __u32 *fwmark)
418{
419 memset(parms, 0, sizeof(*parms));
420
421 parms->iph.version = 4;
422 parms->iph.protocol = IPPROTO_IPIP;
423 parms->iph.ihl = 5;
424 *collect_md = false;
425
426 if (!data)
427 return;
428
429 if (data[IFLA_IPTUN_LINK])
430 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
431
432 if (data[IFLA_IPTUN_LOCAL])
433 parms->iph.saddr = nla_get_in_addr(data[IFLA_IPTUN_LOCAL]);
434
435 if (data[IFLA_IPTUN_REMOTE])
436 parms->iph.daddr = nla_get_in_addr(data[IFLA_IPTUN_REMOTE]);
437
438 if (data[IFLA_IPTUN_TTL]) {
439 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
440 if (parms->iph.ttl)
441 parms->iph.frag_off = htons(IP_DF);
442 }
443
444 if (data[IFLA_IPTUN_TOS])
445 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
446
447 if (data[IFLA_IPTUN_PROTO])
448 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
449
450 if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
451 parms->iph.frag_off = htons(IP_DF);
452
453 if (data[IFLA_IPTUN_COLLECT_METADATA])
454 *collect_md = true;
455
456 if (data[IFLA_IPTUN_FWMARK])
457 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
458}
459
460/* This function returns true when ENCAP attributes are present in the nl msg */
461static bool ipip_netlink_encap_parms(struct nlattr *data[],
462 struct ip_tunnel_encap *ipencap)
463{
464 bool ret = false;
465
466 memset(ipencap, 0, sizeof(*ipencap));
467
468 if (!data)
469 return ret;
470
471 if (data[IFLA_IPTUN_ENCAP_TYPE]) {
472 ret = true;
473 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
474 }
475
476 if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
477 ret = true;
478 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
479 }
480
481 if (data[IFLA_IPTUN_ENCAP_SPORT]) {
482 ret = true;
483 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
484 }
485
486 if (data[IFLA_IPTUN_ENCAP_DPORT]) {
487 ret = true;
488 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
489 }
490
491 return ret;
492}
493
494static int ipip_newlink(struct net *src_net, struct net_device *dev,
495 struct nlattr *tb[], struct nlattr *data[],
496 struct netlink_ext_ack *extack)
497{
498 struct ip_tunnel *t = netdev_priv(dev);
499 struct ip_tunnel_parm p;
500 struct ip_tunnel_encap ipencap;
501 __u32 fwmark = 0;
502
503 if (ipip_netlink_encap_parms(data, &ipencap)) {
504 int err = ip_tunnel_encap_setup(t, &ipencap);
505
506 if (err < 0)
507 return err;
508 }
509
510 ipip_netlink_parms(data, &p, &t->collect_md, &fwmark);
511 return ip_tunnel_newlink(dev, tb, &p, fwmark);
512}
513
514static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
515 struct nlattr *data[],
516 struct netlink_ext_ack *extack)
517{
518 struct ip_tunnel *t = netdev_priv(dev);
519 struct ip_tunnel_parm p;
520 struct ip_tunnel_encap ipencap;
521 bool collect_md;
522 __u32 fwmark = t->fwmark;
523
524 if (ipip_netlink_encap_parms(data, &ipencap)) {
525 int err = ip_tunnel_encap_setup(t, &ipencap);
526
527 if (err < 0)
528 return err;
529 }
530
531 ipip_netlink_parms(data, &p, &collect_md, &fwmark);
532 if (collect_md)
533 return -EINVAL;
534
535 if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
536 (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
537 return -EINVAL;
538
539 return ip_tunnel_changelink(dev, tb, &p, fwmark);
540}
541
542static size_t ipip_get_size(const struct net_device *dev)
543{
544 return
545 /* IFLA_IPTUN_LINK */
546 nla_total_size(4) +
547 /* IFLA_IPTUN_LOCAL */
548 nla_total_size(4) +
549 /* IFLA_IPTUN_REMOTE */
550 nla_total_size(4) +
551 /* IFLA_IPTUN_TTL */
552 nla_total_size(1) +
553 /* IFLA_IPTUN_TOS */
554 nla_total_size(1) +
555 /* IFLA_IPTUN_PROTO */
556 nla_total_size(1) +
557 /* IFLA_IPTUN_PMTUDISC */
558 nla_total_size(1) +
559 /* IFLA_IPTUN_ENCAP_TYPE */
560 nla_total_size(2) +
561 /* IFLA_IPTUN_ENCAP_FLAGS */
562 nla_total_size(2) +
563 /* IFLA_IPTUN_ENCAP_SPORT */
564 nla_total_size(2) +
565 /* IFLA_IPTUN_ENCAP_DPORT */
566 nla_total_size(2) +
567 /* IFLA_IPTUN_COLLECT_METADATA */
568 nla_total_size(0) +
569 /* IFLA_IPTUN_FWMARK */
570 nla_total_size(4) +
571 0;
572}
573
574static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev)
575{
576 struct ip_tunnel *tunnel = netdev_priv(dev);
577 struct ip_tunnel_parm *parm = &tunnel->parms;
578
579 if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
580 nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
581 nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
582 nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
583 nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
584 nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
585 nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
586 !!(parm->iph.frag_off & htons(IP_DF))) ||
587 nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
588 goto nla_put_failure;
589
590 if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
591 tunnel->encap.type) ||
592 nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
593 tunnel->encap.sport) ||
594 nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
595 tunnel->encap.dport) ||
596 nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
597 tunnel->encap.flags))
598 goto nla_put_failure;
599
600 if (tunnel->collect_md)
601 if (nla_put_flag(skb, IFLA_IPTUN_COLLECT_METADATA))
602 goto nla_put_failure;
603 return 0;
604
605nla_put_failure:
606 return -EMSGSIZE;
607}
608
609static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = {
610 [IFLA_IPTUN_LINK] = { .type = NLA_U32 },
611 [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 },
612 [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 },
613 [IFLA_IPTUN_TTL] = { .type = NLA_U8 },
614 [IFLA_IPTUN_TOS] = { .type = NLA_U8 },
615 [IFLA_IPTUN_PROTO] = { .type = NLA_U8 },
616 [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 },
617 [IFLA_IPTUN_ENCAP_TYPE] = { .type = NLA_U16 },
618 [IFLA_IPTUN_ENCAP_FLAGS] = { .type = NLA_U16 },
619 [IFLA_IPTUN_ENCAP_SPORT] = { .type = NLA_U16 },
620 [IFLA_IPTUN_ENCAP_DPORT] = { .type = NLA_U16 },
621 [IFLA_IPTUN_COLLECT_METADATA] = { .type = NLA_FLAG },
622 [IFLA_IPTUN_FWMARK] = { .type = NLA_U32 },
623};
624
625static struct rtnl_link_ops ipip_link_ops __read_mostly = {
626 .kind = "ipip",
627 .maxtype = IFLA_IPTUN_MAX,
628 .policy = ipip_policy,
629 .priv_size = sizeof(struct ip_tunnel),
630 .setup = ipip_tunnel_setup,
631 .validate = ipip_tunnel_validate,
632 .newlink = ipip_newlink,
633 .changelink = ipip_changelink,
634 .dellink = ip_tunnel_dellink,
635 .get_size = ipip_get_size,
636 .fill_info = ipip_fill_info,
637 .get_link_net = ip_tunnel_get_link_net,
638};
639
640static struct xfrm_tunnel ipip_handler __read_mostly = {
641 .handler = ipip_rcv,
642 .err_handler = ipip_err,
643 .priority = 1,
644};
645
646#if IS_ENABLED(CONFIG_MPLS)
647static struct xfrm_tunnel mplsip_handler __read_mostly = {
648 .handler = mplsip_rcv,
649 .err_handler = ipip_err,
650 .priority = 1,
651};
652#endif
653
654static int __net_init ipip_init_net(struct net *net)
655{
656 return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0");
657}
658
659static void __net_exit ipip_exit_batch_net(struct list_head *list_net)
660{
661 ip_tunnel_delete_nets(list_net, ipip_net_id, &ipip_link_ops);
662}
663
664static struct pernet_operations ipip_net_ops = {
665 .init = ipip_init_net,
666 .exit_batch = ipip_exit_batch_net,
667 .id = &ipip_net_id,
668 .size = sizeof(struct ip_tunnel_net),
669};
670
671static int __init ipip_init(void)
672{
673 int err;
674
675 pr_info("ipip: IPv4 and MPLS over IPv4 tunneling driver\n");
676
677 err = register_pernet_device(&ipip_net_ops);
678 if (err < 0)
679 return err;
680 err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
681 if (err < 0) {
682 pr_info("%s: can't register tunnel\n", __func__);
683 goto xfrm_tunnel_ipip_failed;
684 }
685#if IS_ENABLED(CONFIG_MPLS)
686 err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
687 if (err < 0) {
688 pr_info("%s: can't register tunnel\n", __func__);
689 goto xfrm_tunnel_mplsip_failed;
690 }
691#endif
692 err = rtnl_link_register(&ipip_link_ops);
693 if (err < 0)
694 goto rtnl_link_failed;
695
696out:
697 return err;
698
699rtnl_link_failed:
700#if IS_ENABLED(CONFIG_MPLS)
701 xfrm4_tunnel_deregister(&mplsip_handler, AF_INET);
702xfrm_tunnel_mplsip_failed:
703
704#endif
705 xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
706xfrm_tunnel_ipip_failed:
707 unregister_pernet_device(&ipip_net_ops);
708 goto out;
709}
710
711static void __exit ipip_fini(void)
712{
713 rtnl_link_unregister(&ipip_link_ops);
714 if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
715 pr_info("%s: can't deregister tunnel\n", __func__);
716#if IS_ENABLED(CONFIG_MPLS)
717 if (xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS))
718 pr_info("%s: can't deregister tunnel\n", __func__);
719#endif
720 unregister_pernet_device(&ipip_net_ops);
721}
722
723module_init(ipip_init);
724module_exit(ipip_fini);
725MODULE_LICENSE("GPL");
726MODULE_ALIAS_RTNL_LINK("ipip");
727MODULE_ALIAS_NETDEV("tunl0");