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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 <linux/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#include <net/dst_metadata.h>
119
120static bool log_ecn_error = true;
121module_param(log_ecn_error, bool, 0644);
122MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
123
124static unsigned int ipip_net_id __read_mostly;
125
126static int ipip_tunnel_init(struct net_device *dev);
127static struct rtnl_link_ops ipip_link_ops __read_mostly;
128
129static int ipip_err(struct sk_buff *skb, u32 info)
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 const int type = icmp_hdr(skb)->type;
139 const int code = icmp_hdr(skb)->code;
140 struct ip_tunnel *t;
141 int err = 0;
142
143 switch (type) {
144 case ICMP_DEST_UNREACH:
145 switch (code) {
146 case ICMP_SR_FAILED:
147 /* Impossible event. */
148 goto out;
149 default:
150 /* All others are translated to HOST_UNREACH.
151 * rfc2003 contains "deep thoughts" about NET_UNREACH,
152 * I believe they are just ether pollution. --ANK
153 */
154 break;
155 }
156 break;
157
158 case ICMP_TIME_EXCEEDED:
159 if (code != ICMP_EXC_TTL)
160 goto out;
161 break;
162
163 case ICMP_REDIRECT:
164 break;
165
166 default:
167 goto out;
168 }
169
170 t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
171 iph->daddr, iph->saddr, 0);
172 if (!t) {
173 err = -ENOENT;
174 goto out;
175 }
176
177 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
178 ipv4_update_pmtu(skb, net, info, t->parms.link, 0,
179 iph->protocol, 0);
180 goto out;
181 }
182
183 if (type == ICMP_REDIRECT) {
184 ipv4_redirect(skb, net, t->parms.link, 0, iph->protocol, 0);
185 goto out;
186 }
187
188 if (t->parms.iph.daddr == 0) {
189 err = -ENOENT;
190 goto out;
191 }
192
193 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
194 goto out;
195
196 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
197 t->err_count++;
198 else
199 t->err_count = 1;
200 t->err_time = jiffies;
201
202out:
203 return err;
204}
205
206static const struct tnl_ptk_info ipip_tpi = {
207 /* no tunnel info required for ipip. */
208 .proto = htons(ETH_P_IP),
209};
210
211#if IS_ENABLED(CONFIG_MPLS)
212static const struct tnl_ptk_info mplsip_tpi = {
213 /* no tunnel info required for mplsip. */
214 .proto = htons(ETH_P_MPLS_UC),
215};
216#endif
217
218static int ipip_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
219{
220 struct net *net = dev_net(skb->dev);
221 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
222 struct metadata_dst *tun_dst = NULL;
223 struct ip_tunnel *tunnel;
224 const struct iphdr *iph;
225
226 iph = ip_hdr(skb);
227 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
228 iph->saddr, 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 tun_dst = ip_tun_rx_dst(skb, 0, 0, 0);
248 if (!tun_dst)
249 return 0;
250 }
251 return ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
252 }
253
254 return -1;
255
256drop:
257 kfree_skb(skb);
258 return 0;
259}
260
261static int ipip_rcv(struct sk_buff *skb)
262{
263 return ipip_tunnel_rcv(skb, IPPROTO_IPIP);
264}
265
266#if IS_ENABLED(CONFIG_MPLS)
267static int mplsip_rcv(struct sk_buff *skb)
268{
269 return ipip_tunnel_rcv(skb, IPPROTO_MPLS);
270}
271#endif
272
273/*
274 * This function assumes it is being called from dev_queue_xmit()
275 * and that skb is filled properly by that function.
276 */
277static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb,
278 struct net_device *dev)
279{
280 struct ip_tunnel *tunnel = netdev_priv(dev);
281 const struct iphdr *tiph = &tunnel->parms.iph;
282 u8 ipproto;
283
284 switch (skb->protocol) {
285 case htons(ETH_P_IP):
286 ipproto = IPPROTO_IPIP;
287 break;
288#if IS_ENABLED(CONFIG_MPLS)
289 case htons(ETH_P_MPLS_UC):
290 ipproto = IPPROTO_MPLS;
291 break;
292#endif
293 default:
294 goto tx_error;
295 }
296
297 if (tiph->protocol != ipproto && tiph->protocol != 0)
298 goto tx_error;
299
300 if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
301 goto tx_error;
302
303 skb_set_inner_ipproto(skb, ipproto);
304
305 if (tunnel->collect_md)
306 ip_md_tunnel_xmit(skb, dev, ipproto);
307 else
308 ip_tunnel_xmit(skb, dev, tiph, ipproto);
309 return NETDEV_TX_OK;
310
311tx_error:
312 kfree_skb(skb);
313
314 dev->stats.tx_errors++;
315 return NETDEV_TX_OK;
316}
317
318static bool ipip_tunnel_ioctl_verify_protocol(u8 ipproto)
319{
320 switch (ipproto) {
321 case 0:
322 case IPPROTO_IPIP:
323#if IS_ENABLED(CONFIG_MPLS)
324 case IPPROTO_MPLS:
325#endif
326 return true;
327 }
328
329 return false;
330}
331
332static int
333ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
334{
335 int err = 0;
336 struct ip_tunnel_parm p;
337
338 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
339 return -EFAULT;
340
341 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
342 if (p.iph.version != 4 ||
343 !ipip_tunnel_ioctl_verify_protocol(p.iph.protocol) ||
344 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
345 return -EINVAL;
346 }
347
348 p.i_key = p.o_key = 0;
349 p.i_flags = p.o_flags = 0;
350 err = ip_tunnel_ioctl(dev, &p, cmd);
351 if (err)
352 return err;
353
354 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
355 return -EFAULT;
356
357 return 0;
358}
359
360static const struct net_device_ops ipip_netdev_ops = {
361 .ndo_init = ipip_tunnel_init,
362 .ndo_uninit = ip_tunnel_uninit,
363 .ndo_start_xmit = ipip_tunnel_xmit,
364 .ndo_do_ioctl = ipip_tunnel_ioctl,
365 .ndo_change_mtu = ip_tunnel_change_mtu,
366 .ndo_get_stats64 = ip_tunnel_get_stats64,
367 .ndo_get_iflink = ip_tunnel_get_iflink,
368};
369
370#define IPIP_FEATURES (NETIF_F_SG | \
371 NETIF_F_FRAGLIST | \
372 NETIF_F_HIGHDMA | \
373 NETIF_F_GSO_SOFTWARE | \
374 NETIF_F_HW_CSUM)
375
376static void ipip_tunnel_setup(struct net_device *dev)
377{
378 dev->netdev_ops = &ipip_netdev_ops;
379
380 dev->type = ARPHRD_TUNNEL;
381 dev->flags = IFF_NOARP;
382 dev->addr_len = 4;
383 dev->features |= NETIF_F_LLTX;
384 netif_keep_dst(dev);
385
386 dev->features |= IPIP_FEATURES;
387 dev->hw_features |= IPIP_FEATURES;
388 ip_tunnel_setup(dev, ipip_net_id);
389}
390
391static int ipip_tunnel_init(struct net_device *dev)
392{
393 struct ip_tunnel *tunnel = netdev_priv(dev);
394
395 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
396 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
397
398 tunnel->tun_hlen = 0;
399 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
400 return ip_tunnel_init(dev);
401}
402
403static int ipip_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
404 struct netlink_ext_ack *extack)
405{
406 u8 proto;
407
408 if (!data || !data[IFLA_IPTUN_PROTO])
409 return 0;
410
411 proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
412 if (proto != IPPROTO_IPIP && proto != IPPROTO_MPLS && proto != 0)
413 return -EINVAL;
414
415 return 0;
416}
417
418static void ipip_netlink_parms(struct nlattr *data[],
419 struct ip_tunnel_parm *parms, bool *collect_md,
420 __u32 *fwmark)
421{
422 memset(parms, 0, sizeof(*parms));
423
424 parms->iph.version = 4;
425 parms->iph.protocol = IPPROTO_IPIP;
426 parms->iph.ihl = 5;
427 *collect_md = false;
428
429 if (!data)
430 return;
431
432 if (data[IFLA_IPTUN_LINK])
433 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
434
435 if (data[IFLA_IPTUN_LOCAL])
436 parms->iph.saddr = nla_get_in_addr(data[IFLA_IPTUN_LOCAL]);
437
438 if (data[IFLA_IPTUN_REMOTE])
439 parms->iph.daddr = nla_get_in_addr(data[IFLA_IPTUN_REMOTE]);
440
441 if (data[IFLA_IPTUN_TTL]) {
442 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
443 if (parms->iph.ttl)
444 parms->iph.frag_off = htons(IP_DF);
445 }
446
447 if (data[IFLA_IPTUN_TOS])
448 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
449
450 if (data[IFLA_IPTUN_PROTO])
451 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
452
453 if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
454 parms->iph.frag_off = htons(IP_DF);
455
456 if (data[IFLA_IPTUN_COLLECT_METADATA])
457 *collect_md = true;
458
459 if (data[IFLA_IPTUN_FWMARK])
460 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
461}
462
463/* This function returns true when ENCAP attributes are present in the nl msg */
464static bool ipip_netlink_encap_parms(struct nlattr *data[],
465 struct ip_tunnel_encap *ipencap)
466{
467 bool ret = false;
468
469 memset(ipencap, 0, sizeof(*ipencap));
470
471 if (!data)
472 return ret;
473
474 if (data[IFLA_IPTUN_ENCAP_TYPE]) {
475 ret = true;
476 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
477 }
478
479 if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
480 ret = true;
481 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
482 }
483
484 if (data[IFLA_IPTUN_ENCAP_SPORT]) {
485 ret = true;
486 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
487 }
488
489 if (data[IFLA_IPTUN_ENCAP_DPORT]) {
490 ret = true;
491 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
492 }
493
494 return ret;
495}
496
497static int ipip_newlink(struct net *src_net, struct net_device *dev,
498 struct nlattr *tb[], struct nlattr *data[],
499 struct netlink_ext_ack *extack)
500{
501 struct ip_tunnel *t = netdev_priv(dev);
502 struct ip_tunnel_parm p;
503 struct ip_tunnel_encap ipencap;
504 __u32 fwmark = 0;
505
506 if (ipip_netlink_encap_parms(data, &ipencap)) {
507 int err = ip_tunnel_encap_setup(t, &ipencap);
508
509 if (err < 0)
510 return err;
511 }
512
513 ipip_netlink_parms(data, &p, &t->collect_md, &fwmark);
514 return ip_tunnel_newlink(dev, tb, &p, fwmark);
515}
516
517static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
518 struct nlattr *data[],
519 struct netlink_ext_ack *extack)
520{
521 struct ip_tunnel *t = netdev_priv(dev);
522 struct ip_tunnel_parm p;
523 struct ip_tunnel_encap ipencap;
524 bool collect_md;
525 __u32 fwmark = t->fwmark;
526
527 if (ipip_netlink_encap_parms(data, &ipencap)) {
528 int err = ip_tunnel_encap_setup(t, &ipencap);
529
530 if (err < 0)
531 return err;
532 }
533
534 ipip_netlink_parms(data, &p, &collect_md, &fwmark);
535 if (collect_md)
536 return -EINVAL;
537
538 if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
539 (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
540 return -EINVAL;
541
542 return ip_tunnel_changelink(dev, tb, &p, fwmark);
543}
544
545static size_t ipip_get_size(const struct net_device *dev)
546{
547 return
548 /* IFLA_IPTUN_LINK */
549 nla_total_size(4) +
550 /* IFLA_IPTUN_LOCAL */
551 nla_total_size(4) +
552 /* IFLA_IPTUN_REMOTE */
553 nla_total_size(4) +
554 /* IFLA_IPTUN_TTL */
555 nla_total_size(1) +
556 /* IFLA_IPTUN_TOS */
557 nla_total_size(1) +
558 /* IFLA_IPTUN_PROTO */
559 nla_total_size(1) +
560 /* IFLA_IPTUN_PMTUDISC */
561 nla_total_size(1) +
562 /* IFLA_IPTUN_ENCAP_TYPE */
563 nla_total_size(2) +
564 /* IFLA_IPTUN_ENCAP_FLAGS */
565 nla_total_size(2) +
566 /* IFLA_IPTUN_ENCAP_SPORT */
567 nla_total_size(2) +
568 /* IFLA_IPTUN_ENCAP_DPORT */
569 nla_total_size(2) +
570 /* IFLA_IPTUN_COLLECT_METADATA */
571 nla_total_size(0) +
572 /* IFLA_IPTUN_FWMARK */
573 nla_total_size(4) +
574 0;
575}
576
577static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev)
578{
579 struct ip_tunnel *tunnel = netdev_priv(dev);
580 struct ip_tunnel_parm *parm = &tunnel->parms;
581
582 if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
583 nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
584 nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
585 nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
586 nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
587 nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
588 nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
589 !!(parm->iph.frag_off & htons(IP_DF))) ||
590 nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
591 goto nla_put_failure;
592
593 if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
594 tunnel->encap.type) ||
595 nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
596 tunnel->encap.sport) ||
597 nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
598 tunnel->encap.dport) ||
599 nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
600 tunnel->encap.flags))
601 goto nla_put_failure;
602
603 if (tunnel->collect_md)
604 if (nla_put_flag(skb, IFLA_IPTUN_COLLECT_METADATA))
605 goto nla_put_failure;
606 return 0;
607
608nla_put_failure:
609 return -EMSGSIZE;
610}
611
612static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = {
613 [IFLA_IPTUN_LINK] = { .type = NLA_U32 },
614 [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 },
615 [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 },
616 [IFLA_IPTUN_TTL] = { .type = NLA_U8 },
617 [IFLA_IPTUN_TOS] = { .type = NLA_U8 },
618 [IFLA_IPTUN_PROTO] = { .type = NLA_U8 },
619 [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 },
620 [IFLA_IPTUN_ENCAP_TYPE] = { .type = NLA_U16 },
621 [IFLA_IPTUN_ENCAP_FLAGS] = { .type = NLA_U16 },
622 [IFLA_IPTUN_ENCAP_SPORT] = { .type = NLA_U16 },
623 [IFLA_IPTUN_ENCAP_DPORT] = { .type = NLA_U16 },
624 [IFLA_IPTUN_COLLECT_METADATA] = { .type = NLA_FLAG },
625 [IFLA_IPTUN_FWMARK] = { .type = NLA_U32 },
626};
627
628static struct rtnl_link_ops ipip_link_ops __read_mostly = {
629 .kind = "ipip",
630 .maxtype = IFLA_IPTUN_MAX,
631 .policy = ipip_policy,
632 .priv_size = sizeof(struct ip_tunnel),
633 .setup = ipip_tunnel_setup,
634 .validate = ipip_tunnel_validate,
635 .newlink = ipip_newlink,
636 .changelink = ipip_changelink,
637 .dellink = ip_tunnel_dellink,
638 .get_size = ipip_get_size,
639 .fill_info = ipip_fill_info,
640 .get_link_net = ip_tunnel_get_link_net,
641};
642
643static struct xfrm_tunnel ipip_handler __read_mostly = {
644 .handler = ipip_rcv,
645 .err_handler = ipip_err,
646 .priority = 1,
647};
648
649#if IS_ENABLED(CONFIG_MPLS)
650static struct xfrm_tunnel mplsip_handler __read_mostly = {
651 .handler = mplsip_rcv,
652 .err_handler = ipip_err,
653 .priority = 1,
654};
655#endif
656
657static int __net_init ipip_init_net(struct net *net)
658{
659 return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0");
660}
661
662static void __net_exit ipip_exit_batch_net(struct list_head *list_net)
663{
664 ip_tunnel_delete_nets(list_net, ipip_net_id, &ipip_link_ops);
665}
666
667static struct pernet_operations ipip_net_ops = {
668 .init = ipip_init_net,
669 .exit_batch = ipip_exit_batch_net,
670 .id = &ipip_net_id,
671 .size = sizeof(struct ip_tunnel_net),
672};
673
674static int __init ipip_init(void)
675{
676 int err;
677
678 pr_info("ipip: IPv4 and MPLS over IPv4 tunneling driver\n");
679
680 err = register_pernet_device(&ipip_net_ops);
681 if (err < 0)
682 return err;
683 err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
684 if (err < 0) {
685 pr_info("%s: can't register tunnel\n", __func__);
686 goto xfrm_tunnel_ipip_failed;
687 }
688#if IS_ENABLED(CONFIG_MPLS)
689 err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
690 if (err < 0) {
691 pr_info("%s: can't register tunnel\n", __func__);
692 goto xfrm_tunnel_mplsip_failed;
693 }
694#endif
695 err = rtnl_link_register(&ipip_link_ops);
696 if (err < 0)
697 goto rtnl_link_failed;
698
699out:
700 return err;
701
702rtnl_link_failed:
703#if IS_ENABLED(CONFIG_MPLS)
704 xfrm4_tunnel_deregister(&mplsip_handler, AF_INET);
705xfrm_tunnel_mplsip_failed:
706
707#endif
708 xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
709xfrm_tunnel_ipip_failed:
710 unregister_pernet_device(&ipip_net_ops);
711 goto out;
712}
713
714static void __exit ipip_fini(void)
715{
716 rtnl_link_unregister(&ipip_link_ops);
717 if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
718 pr_info("%s: can't deregister tunnel\n", __func__);
719#if IS_ENABLED(CONFIG_MPLS)
720 if (xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS))
721 pr_info("%s: can't deregister tunnel\n", __func__);
722#endif
723 unregister_pernet_device(&ipip_net_ops);
724}
725
726module_init(ipip_init);
727module_exit(ipip_fini);
728MODULE_LICENSE("GPL");
729MODULE_ALIAS_RTNL_LINK("ipip");
730MODULE_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/mroute.h>
107#include <linux/init.h>
108#include <linux/netfilter_ipv4.h>
109#include <linux/if_ether.h>
110
111#include <net/sock.h>
112#include <net/ip.h>
113#include <net/icmp.h>
114#include <net/ip_tunnels.h>
115#include <net/inet_ecn.h>
116#include <net/xfrm.h>
117#include <net/net_namespace.h>
118#include <net/netns/generic.h>
119
120static bool log_ecn_error = true;
121module_param(log_ecn_error, bool, 0644);
122MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
123
124static int ipip_net_id __read_mostly;
125
126static int ipip_tunnel_init(struct net_device *dev);
127static struct rtnl_link_ops ipip_link_ops __read_mostly;
128
129static int ipip_err(struct sk_buff *skb, u32 info)
130{
131
132/* All the routers (except for Linux) return only
133 8 bytes of packet payload. It means, that precise relaying of
134 ICMP in the real Internet is absolutely infeasible.
135 */
136 struct net *net = dev_net(skb->dev);
137 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
138 const struct iphdr *iph = (const struct iphdr *)skb->data;
139 struct ip_tunnel *t;
140 int err;
141 const int type = icmp_hdr(skb)->type;
142 const int code = icmp_hdr(skb)->code;
143
144 err = -ENOENT;
145 t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
146 iph->daddr, iph->saddr, 0);
147 if (t == NULL)
148 goto out;
149
150 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
151 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
152 t->dev->ifindex, 0, IPPROTO_IPIP, 0);
153 err = 0;
154 goto out;
155 }
156
157 if (type == ICMP_REDIRECT) {
158 ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0,
159 IPPROTO_IPIP, 0);
160 err = 0;
161 goto out;
162 }
163
164 if (t->parms.iph.daddr == 0)
165 goto out;
166
167 err = 0;
168 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
169 goto out;
170
171 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
172 t->err_count++;
173 else
174 t->err_count = 1;
175 t->err_time = jiffies;
176
177out:
178 return err;
179}
180
181static const struct tnl_ptk_info tpi = {
182 /* no tunnel info required for ipip. */
183 .proto = htons(ETH_P_IP),
184};
185
186static int ipip_rcv(struct sk_buff *skb)
187{
188 struct net *net = dev_net(skb->dev);
189 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
190 struct ip_tunnel *tunnel;
191 const struct iphdr *iph;
192
193 iph = ip_hdr(skb);
194 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
195 iph->saddr, iph->daddr, 0);
196 if (tunnel) {
197 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
198 goto drop;
199 if (iptunnel_pull_header(skb, 0, tpi.proto))
200 goto drop;
201 return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error);
202 }
203
204 return -1;
205
206drop:
207 kfree_skb(skb);
208 return 0;
209}
210
211/*
212 * This function assumes it is being called from dev_queue_xmit()
213 * and that skb is filled properly by that function.
214 */
215static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
216{
217 struct ip_tunnel *tunnel = netdev_priv(dev);
218 const struct iphdr *tiph = &tunnel->parms.iph;
219
220 if (unlikely(skb->protocol != htons(ETH_P_IP)))
221 goto tx_error;
222
223 skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP);
224 if (IS_ERR(skb))
225 goto out;
226
227 ip_tunnel_xmit(skb, dev, tiph, tiph->protocol);
228 return NETDEV_TX_OK;
229
230tx_error:
231 kfree_skb(skb);
232out:
233 dev->stats.tx_errors++;
234 return NETDEV_TX_OK;
235}
236
237static int
238ipip_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
239{
240 int err = 0;
241 struct ip_tunnel_parm p;
242
243 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
244 return -EFAULT;
245
246 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
247 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
248 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
249 return -EINVAL;
250 }
251
252 p.i_key = p.o_key = p.i_flags = p.o_flags = 0;
253 if (p.iph.ttl)
254 p.iph.frag_off |= htons(IP_DF);
255
256 err = ip_tunnel_ioctl(dev, &p, cmd);
257 if (err)
258 return err;
259
260 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
261 return -EFAULT;
262
263 return 0;
264}
265
266static const struct net_device_ops ipip_netdev_ops = {
267 .ndo_init = ipip_tunnel_init,
268 .ndo_uninit = ip_tunnel_uninit,
269 .ndo_start_xmit = ipip_tunnel_xmit,
270 .ndo_do_ioctl = ipip_tunnel_ioctl,
271 .ndo_change_mtu = ip_tunnel_change_mtu,
272 .ndo_get_stats64 = ip_tunnel_get_stats64,
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->iflink = 0;
288 dev->addr_len = 4;
289 dev->features |= NETIF_F_LLTX;
290 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
291
292 dev->features |= IPIP_FEATURES;
293 dev->hw_features |= IPIP_FEATURES;
294 ip_tunnel_setup(dev, ipip_net_id);
295}
296
297static int ipip_tunnel_init(struct net_device *dev)
298{
299 struct ip_tunnel *tunnel = netdev_priv(dev);
300
301 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
302 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
303
304 tunnel->hlen = 0;
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_be32(data[IFLA_IPTUN_LOCAL]);
326
327 if (data[IFLA_IPTUN_REMOTE])
328 parms->iph.daddr = nla_get_be32(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
343static int ipip_newlink(struct net *src_net, struct net_device *dev,
344 struct nlattr *tb[], struct nlattr *data[])
345{
346 struct ip_tunnel_parm p;
347
348 ipip_netlink_parms(data, &p);
349 return ip_tunnel_newlink(dev, tb, &p);
350}
351
352static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],
353 struct nlattr *data[])
354{
355 struct ip_tunnel_parm p;
356
357 ipip_netlink_parms(data, &p);
358
359 if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
360 (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
361 return -EINVAL;
362
363 return ip_tunnel_changelink(dev, tb, &p);
364}
365
366static size_t ipip_get_size(const struct net_device *dev)
367{
368 return
369 /* IFLA_IPTUN_LINK */
370 nla_total_size(4) +
371 /* IFLA_IPTUN_LOCAL */
372 nla_total_size(4) +
373 /* IFLA_IPTUN_REMOTE */
374 nla_total_size(4) +
375 /* IFLA_IPTUN_TTL */
376 nla_total_size(1) +
377 /* IFLA_IPTUN_TOS */
378 nla_total_size(1) +
379 /* IFLA_IPTUN_PMTUDISC */
380 nla_total_size(1) +
381 0;
382}
383
384static int ipip_fill_info(struct sk_buff *skb, const struct net_device *dev)
385{
386 struct ip_tunnel *tunnel = netdev_priv(dev);
387 struct ip_tunnel_parm *parm = &tunnel->parms;
388
389 if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
390 nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
391 nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
392 nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
393 nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
394 nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
395 !!(parm->iph.frag_off & htons(IP_DF))))
396 goto nla_put_failure;
397 return 0;
398
399nla_put_failure:
400 return -EMSGSIZE;
401}
402
403static const struct nla_policy ipip_policy[IFLA_IPTUN_MAX + 1] = {
404 [IFLA_IPTUN_LINK] = { .type = NLA_U32 },
405 [IFLA_IPTUN_LOCAL] = { .type = NLA_U32 },
406 [IFLA_IPTUN_REMOTE] = { .type = NLA_U32 },
407 [IFLA_IPTUN_TTL] = { .type = NLA_U8 },
408 [IFLA_IPTUN_TOS] = { .type = NLA_U8 },
409 [IFLA_IPTUN_PMTUDISC] = { .type = NLA_U8 },
410};
411
412static struct rtnl_link_ops ipip_link_ops __read_mostly = {
413 .kind = "ipip",
414 .maxtype = IFLA_IPTUN_MAX,
415 .policy = ipip_policy,
416 .priv_size = sizeof(struct ip_tunnel),
417 .setup = ipip_tunnel_setup,
418 .newlink = ipip_newlink,
419 .changelink = ipip_changelink,
420 .dellink = ip_tunnel_dellink,
421 .get_size = ipip_get_size,
422 .fill_info = ipip_fill_info,
423};
424
425static struct xfrm_tunnel ipip_handler __read_mostly = {
426 .handler = ipip_rcv,
427 .err_handler = ipip_err,
428 .priority = 1,
429};
430
431static int __net_init ipip_init_net(struct net *net)
432{
433 return ip_tunnel_init_net(net, ipip_net_id, &ipip_link_ops, "tunl0");
434}
435
436static void __net_exit ipip_exit_net(struct net *net)
437{
438 struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
439 ip_tunnel_delete_net(itn, &ipip_link_ops);
440}
441
442static struct pernet_operations ipip_net_ops = {
443 .init = ipip_init_net,
444 .exit = ipip_exit_net,
445 .id = &ipip_net_id,
446 .size = sizeof(struct ip_tunnel_net),
447};
448
449static int __init ipip_init(void)
450{
451 int err;
452
453 pr_info("ipip: IPv4 over IPv4 tunneling driver\n");
454
455 err = register_pernet_device(&ipip_net_ops);
456 if (err < 0)
457 return err;
458 err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
459 if (err < 0) {
460 pr_info("%s: can't register tunnel\n", __func__);
461 goto xfrm_tunnel_failed;
462 }
463 err = rtnl_link_register(&ipip_link_ops);
464 if (err < 0)
465 goto rtnl_link_failed;
466
467out:
468 return err;
469
470rtnl_link_failed:
471 xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
472xfrm_tunnel_failed:
473 unregister_pernet_device(&ipip_net_ops);
474 goto out;
475}
476
477static void __exit ipip_fini(void)
478{
479 rtnl_link_unregister(&ipip_link_ops);
480 if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
481 pr_info("%s: can't deregister tunnel\n", __func__);
482
483 unregister_pernet_device(&ipip_net_ops);
484}
485
486module_init(ipip_init);
487module_exit(ipip_fini);
488MODULE_LICENSE("GPL");
489MODULE_ALIAS_NETDEV("tunl0");