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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 IP_TUNNEL_DECLARE_FLAGS(flags) = { };
134 const int type = icmp_hdr(skb)->type;
135 const int code = icmp_hdr(skb)->code;
136 struct ip_tunnel *t;
137 int err = 0;
138
139 __set_bit(IP_TUNNEL_NO_KEY_BIT, flags);
140
141 t = ip_tunnel_lookup(itn, skb->dev->ifindex, flags, iph->daddr,
142 iph->saddr, 0);
143 if (!t) {
144 err = -ENOENT;
145 goto out;
146 }
147
148 switch (type) {
149 case ICMP_DEST_UNREACH:
150 switch (code) {
151 case ICMP_SR_FAILED:
152 /* Impossible event. */
153 goto out;
154 default:
155 /* All others are translated to HOST_UNREACH.
156 * rfc2003 contains "deep thoughts" about NET_UNREACH,
157 * I believe they are just ether pollution. --ANK
158 */
159 break;
160 }
161 break;
162
163 case ICMP_TIME_EXCEEDED:
164 if (code != ICMP_EXC_TTL)
165 goto out;
166 break;
167
168 case ICMP_REDIRECT:
169 break;
170
171 default:
172 goto out;
173 }
174
175 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
176 ipv4_update_pmtu(skb, net, info, t->parms.link, iph->protocol);
177 goto out;
178 }
179
180 if (type == ICMP_REDIRECT) {
181 ipv4_redirect(skb, net, t->parms.link, iph->protocol);
182 goto out;
183 }
184
185 if (t->parms.iph.daddr == 0) {
186 err = -ENOENT;
187 goto out;
188 }
189
190 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
191 goto out;
192
193 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
194 t->err_count++;
195 else
196 t->err_count = 1;
197 t->err_time = jiffies;
198
199out:
200 return err;
201}
202
203static const struct tnl_ptk_info ipip_tpi = {
204 /* no tunnel info required for ipip. */
205 .proto = htons(ETH_P_IP),
206};
207
208#if IS_ENABLED(CONFIG_MPLS)
209static const struct tnl_ptk_info mplsip_tpi = {
210 /* no tunnel info required for mplsip. */
211 .proto = htons(ETH_P_MPLS_UC),
212};
213#endif
214
215static int ipip_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
216{
217 struct net *net = dev_net(skb->dev);
218 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
219 IP_TUNNEL_DECLARE_FLAGS(flags) = { };
220 struct metadata_dst *tun_dst = NULL;
221 struct ip_tunnel *tunnel;
222 const struct iphdr *iph;
223
224 __set_bit(IP_TUNNEL_NO_KEY_BIT, flags);
225
226 iph = ip_hdr(skb);
227 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, flags, iph->saddr,
228 iph->daddr, 0);
229 if (tunnel) {
230 const struct tnl_ptk_info *tpi;
231
232 if (tunnel->parms.iph.protocol != ipproto &&
233 tunnel->parms.iph.protocol != 0)
234 goto drop;
235
236 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
237 goto drop;
238#if IS_ENABLED(CONFIG_MPLS)
239 if (ipproto == IPPROTO_MPLS)
240 tpi = &mplsip_tpi;
241 else
242#endif
243 tpi = &ipip_tpi;
244 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
245 goto drop;
246 if (tunnel->collect_md) {
247 ip_tunnel_flags_zero(flags);
248
249 tun_dst = ip_tun_rx_dst(skb, flags, 0, 0);
250 if (!tun_dst)
251 return 0;
252 ip_tunnel_md_udp_encap(skb, &tun_dst->u.tun_info);
253 }
254 skb_reset_mac_header(skb);
255
256 return ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
257 }
258
259 return -1;
260
261drop:
262 kfree_skb(skb);
263 return 0;
264}
265
266static int ipip_rcv(struct sk_buff *skb)
267{
268 return ipip_tunnel_rcv(skb, IPPROTO_IPIP);
269}
270
271#if IS_ENABLED(CONFIG_MPLS)
272static int mplsip_rcv(struct sk_buff *skb)
273{
274 return ipip_tunnel_rcv(skb, IPPROTO_MPLS);
275}
276#endif
277
278/*
279 * This function assumes it is being called from dev_queue_xmit()
280 * and that skb is filled properly by that function.
281 */
282static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb,
283 struct net_device *dev)
284{
285 struct ip_tunnel *tunnel = netdev_priv(dev);
286 const struct iphdr *tiph = &tunnel->parms.iph;
287 u8 ipproto;
288
289 if (!pskb_inet_may_pull(skb))
290 goto tx_error;
291
292 switch (skb->protocol) {
293 case htons(ETH_P_IP):
294 ipproto = IPPROTO_IPIP;
295 break;
296#if IS_ENABLED(CONFIG_MPLS)
297 case htons(ETH_P_MPLS_UC):
298 ipproto = IPPROTO_MPLS;
299 break;
300#endif
301 default:
302 goto tx_error;
303 }
304
305 if (tiph->protocol != ipproto && tiph->protocol != 0)
306 goto tx_error;
307
308 if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
309 goto tx_error;
310
311 skb_set_inner_ipproto(skb, ipproto);
312
313 if (tunnel->collect_md)
314 ip_md_tunnel_xmit(skb, dev, ipproto, 0);
315 else
316 ip_tunnel_xmit(skb, dev, tiph, ipproto);
317 return NETDEV_TX_OK;
318
319tx_error:
320 kfree_skb(skb);
321
322 DEV_STATS_INC(dev, tx_errors);
323 return NETDEV_TX_OK;
324}
325
326static bool ipip_tunnel_ioctl_verify_protocol(u8 ipproto)
327{
328 switch (ipproto) {
329 case 0:
330 case IPPROTO_IPIP:
331#if IS_ENABLED(CONFIG_MPLS)
332 case IPPROTO_MPLS:
333#endif
334 return true;
335 }
336
337 return false;
338}
339
340static int
341ipip_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm_kern *p, int cmd)
342{
343 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
344 if (p->iph.version != 4 ||
345 !ipip_tunnel_ioctl_verify_protocol(p->iph.protocol) ||
346 p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)))
347 return -EINVAL;
348 }
349
350 p->i_key = p->o_key = 0;
351 ip_tunnel_flags_zero(p->i_flags);
352 ip_tunnel_flags_zero(p->o_flags);
353 return ip_tunnel_ctl(dev, p, cmd);
354}
355
356static const struct net_device_ops ipip_netdev_ops = {
357 .ndo_init = ipip_tunnel_init,
358 .ndo_uninit = ip_tunnel_uninit,
359 .ndo_start_xmit = ipip_tunnel_xmit,
360 .ndo_siocdevprivate = ip_tunnel_siocdevprivate,
361 .ndo_change_mtu = ip_tunnel_change_mtu,
362 .ndo_get_stats64 = dev_get_tstats64,
363 .ndo_get_iflink = ip_tunnel_get_iflink,
364 .ndo_tunnel_ctl = ipip_tunnel_ctl,
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 dev->header_ops = &ip_tunnel_header_ops;
377
378 dev->type = ARPHRD_TUNNEL;
379 dev->flags = IFF_NOARP;
380 dev->addr_len = 4;
381 dev->lltx = true;
382 netif_keep_dst(dev);
383
384 dev->features |= IPIP_FEATURES;
385 dev->hw_features |= IPIP_FEATURES;
386 ip_tunnel_setup(dev, ipip_net_id);
387}
388
389static int ipip_tunnel_init(struct net_device *dev)
390{
391 struct ip_tunnel *tunnel = netdev_priv(dev);
392
393 __dev_addr_set(dev, &tunnel->parms.iph.saddr, 4);
394 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
395
396 tunnel->tun_hlen = 0;
397 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
398 return ip_tunnel_init(dev);
399}
400
401static int ipip_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
402 struct netlink_ext_ack *extack)
403{
404 u8 proto;
405
406 if (!data || !data[IFLA_IPTUN_PROTO])
407 return 0;
408
409 proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
410 if (proto != IPPROTO_IPIP && proto != IPPROTO_MPLS && proto != 0)
411 return -EINVAL;
412
413 return 0;
414}
415
416static void ipip_netlink_parms(struct nlattr *data[],
417 struct ip_tunnel_parm_kern *parms,
418 bool *collect_md, __u32 *fwmark)
419{
420 memset(parms, 0, sizeof(*parms));
421
422 parms->iph.version = 4;
423 parms->iph.protocol = IPPROTO_IPIP;
424 parms->iph.ihl = 5;
425 *collect_md = false;
426
427 if (!data)
428 return;
429
430 ip_tunnel_netlink_parms(data, parms);
431
432 if (data[IFLA_IPTUN_COLLECT_METADATA])
433 *collect_md = true;
434
435 if (data[IFLA_IPTUN_FWMARK])
436 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
437}
438
439static int ipip_newlink(struct net *src_net, struct net_device *dev,
440 struct nlattr *tb[], struct nlattr *data[],
441 struct netlink_ext_ack *extack)
442{
443 struct ip_tunnel *t = netdev_priv(dev);
444 struct ip_tunnel_encap ipencap;
445 struct ip_tunnel_parm_kern p;
446 __u32 fwmark = 0;
447
448 if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
449 int err = ip_tunnel_encap_setup(t, &ipencap);
450
451 if (err < 0)
452 return err;
453 }
454
455 ipip_netlink_parms(data, &p, &t->collect_md, &fwmark);
456 return ip_tunnel_newlink(dev, tb, &p, fwmark);
457}
458
459static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
460 struct nlattr *data[],
461 struct netlink_ext_ack *extack)
462{
463 struct ip_tunnel *t = netdev_priv(dev);
464 struct ip_tunnel_encap ipencap;
465 struct ip_tunnel_parm_kern p;
466 bool collect_md;
467 __u32 fwmark = t->fwmark;
468
469 if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
470 int err = ip_tunnel_encap_setup(t, &ipencap);
471
472 if (err < 0)
473 return err;
474 }
475
476 ipip_netlink_parms(data, &p, &collect_md, &fwmark);
477 if (collect_md)
478 return -EINVAL;
479
480 if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
481 (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
482 return -EINVAL;
483
484 return ip_tunnel_changelink(dev, tb, &p, fwmark);
485}
486
487static size_t ipip_get_size(const struct net_device *dev)
488{
489 return
490 /* IFLA_IPTUN_LINK */
491 nla_total_size(4) +
492 /* IFLA_IPTUN_LOCAL */
493 nla_total_size(4) +
494 /* IFLA_IPTUN_REMOTE */
495 nla_total_size(4) +
496 /* IFLA_IPTUN_TTL */
497 nla_total_size(1) +
498 /* IFLA_IPTUN_TOS */
499 nla_total_size(1) +
500 /* IFLA_IPTUN_PROTO */
501 nla_total_size(1) +
502 /* IFLA_IPTUN_PMTUDISC */
503 nla_total_size(1) +
504 /* IFLA_IPTUN_ENCAP_TYPE */
505 nla_total_size(2) +
506 /* IFLA_IPTUN_ENCAP_FLAGS */
507 nla_total_size(2) +
508 /* IFLA_IPTUN_ENCAP_SPORT */
509 nla_total_size(2) +
510 /* IFLA_IPTUN_ENCAP_DPORT */
511 nla_total_size(2) +
512 /* IFLA_IPTUN_COLLECT_METADATA */
513 nla_total_size(0) +
514 /* IFLA_IPTUN_FWMARK */
515 nla_total_size(4) +
516 0;
517}
518
519static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev)
520{
521 struct ip_tunnel *tunnel = netdev_priv(dev);
522 struct ip_tunnel_parm_kern *parm = &tunnel->parms;
523
524 if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
525 nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
526 nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
527 nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
528 nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
529 nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
530 nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
531 !!(parm->iph.frag_off & htons(IP_DF))) ||
532 nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
533 goto nla_put_failure;
534
535 if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
536 tunnel->encap.type) ||
537 nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
538 tunnel->encap.sport) ||
539 nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
540 tunnel->encap.dport) ||
541 nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
542 tunnel->encap.flags))
543 goto nla_put_failure;
544
545 if (tunnel->collect_md)
546 if (nla_put_flag(skb, IFLA_IPTUN_COLLECT_METADATA))
547 goto nla_put_failure;
548 return 0;
549
550nla_put_failure:
551 return -EMSGSIZE;
552}
553
554static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = {
555 [IFLA_IPTUN_LINK] = { .type = NLA_U32 },
556 [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 },
557 [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 },
558 [IFLA_IPTUN_TTL] = { .type = NLA_U8 },
559 [IFLA_IPTUN_TOS] = { .type = NLA_U8 },
560 [IFLA_IPTUN_PROTO] = { .type = NLA_U8 },
561 [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 },
562 [IFLA_IPTUN_ENCAP_TYPE] = { .type = NLA_U16 },
563 [IFLA_IPTUN_ENCAP_FLAGS] = { .type = NLA_U16 },
564 [IFLA_IPTUN_ENCAP_SPORT] = { .type = NLA_U16 },
565 [IFLA_IPTUN_ENCAP_DPORT] = { .type = NLA_U16 },
566 [IFLA_IPTUN_COLLECT_METADATA] = { .type = NLA_FLAG },
567 [IFLA_IPTUN_FWMARK] = { .type = NLA_U32 },
568};
569
570static struct rtnl_link_ops ipip_link_ops __read_mostly = {
571 .kind = "ipip",
572 .maxtype = IFLA_IPTUN_MAX,
573 .policy = ipip_policy,
574 .priv_size = sizeof(struct ip_tunnel),
575 .setup = ipip_tunnel_setup,
576 .validate = ipip_tunnel_validate,
577 .newlink = ipip_newlink,
578 .changelink = ipip_changelink,
579 .dellink = ip_tunnel_dellink,
580 .get_size = ipip_get_size,
581 .fill_info = ipip_fill_info,
582 .get_link_net = ip_tunnel_get_link_net,
583};
584
585static struct xfrm_tunnel ipip_handler __read_mostly = {
586 .handler = ipip_rcv,
587 .err_handler = ipip_err,
588 .priority = 1,
589};
590
591#if IS_ENABLED(CONFIG_MPLS)
592static struct xfrm_tunnel mplsip_handler __read_mostly = {
593 .handler = mplsip_rcv,
594 .err_handler = ipip_err,
595 .priority = 1,
596};
597#endif
598
599static int __net_init ipip_init_net(struct net *net)
600{
601 return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0");
602}
603
604static void __net_exit ipip_exit_batch_rtnl(struct list_head *list_net,
605 struct list_head *dev_to_kill)
606{
607 ip_tunnel_delete_nets(list_net, ipip_net_id, &ipip_link_ops,
608 dev_to_kill);
609}
610
611static struct pernet_operations ipip_net_ops = {
612 .init = ipip_init_net,
613 .exit_batch_rtnl = ipip_exit_batch_rtnl,
614 .id = &ipip_net_id,
615 .size = sizeof(struct ip_tunnel_net),
616};
617
618static int __init ipip_init(void)
619{
620 int err;
621
622 pr_info("ipip: IPv4 and MPLS over IPv4 tunneling driver\n");
623
624 err = register_pernet_device(&ipip_net_ops);
625 if (err < 0)
626 return err;
627 err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
628 if (err < 0) {
629 pr_info("%s: can't register tunnel\n", __func__);
630 goto xfrm_tunnel_ipip_failed;
631 }
632#if IS_ENABLED(CONFIG_MPLS)
633 err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
634 if (err < 0) {
635 pr_info("%s: can't register tunnel\n", __func__);
636 goto xfrm_tunnel_mplsip_failed;
637 }
638#endif
639 err = rtnl_link_register(&ipip_link_ops);
640 if (err < 0)
641 goto rtnl_link_failed;
642
643out:
644 return err;
645
646rtnl_link_failed:
647#if IS_ENABLED(CONFIG_MPLS)
648 xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
649xfrm_tunnel_mplsip_failed:
650
651#endif
652 xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
653xfrm_tunnel_ipip_failed:
654 unregister_pernet_device(&ipip_net_ops);
655 goto out;
656}
657
658static void __exit ipip_fini(void)
659{
660 rtnl_link_unregister(&ipip_link_ops);
661 if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
662 pr_info("%s: can't deregister tunnel\n", __func__);
663#if IS_ENABLED(CONFIG_MPLS)
664 if (xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS))
665 pr_info("%s: can't deregister tunnel\n", __func__);
666#endif
667 unregister_pernet_device(&ipip_net_ops);
668}
669
670module_init(ipip_init);
671module_exit(ipip_fini);
672MODULE_DESCRIPTION("IP/IP protocol decoder library");
673MODULE_LICENSE("GPL");
674MODULE_ALIAS_RTNL_LINK("ipip");
675MODULE_ALIAS_NETDEV("tunl0");
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");