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[IPSEC]: Set skb->data to payload in x->mode->output
[linux-2.6.git] / net / ipv6 / mip6.c
blob0e7a60f7393a73ea468893cd754f26470a6d14fc
1 /*
2 * Copyright (C)2003-2006 Helsinki University of Technology
3 * Copyright (C)2003-2006 USAGI/WIDE Project
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19 /*
20 * Authors:
21 * Noriaki TAKAMIYA @USAGI
22 * Masahide NAKAMURA @USAGI
23 */
24
25 #include <linux/module.h>
26 #include <linux/skbuff.h>
27 #include <linux/time.h>
28 #include <linux/ipv6.h>
29 #include <linux/icmpv6.h>
30 #include <net/sock.h>
31 #include <net/ipv6.h>
32 #include <net/ip6_checksum.h>
33 #include <net/rawv6.h>
34 #include <net/xfrm.h>
35 #include <net/mip6.h>
36
37 static xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr)
38 {
39 return x->coaddr;
40 }
41
42 static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
43 {
44 return (n - len + 16) & 0x7;
45 }
46
47 static inline void *mip6_padn(__u8 *data, __u8 padlen)
48 {
49 if (!data)
50 return NULL;
51 if (padlen == 1) {
52 data[0] = MIP6_OPT_PAD_1;
53 } else if (padlen > 1) {
54 data[0] = MIP6_OPT_PAD_N;
55 data[1] = padlen - 2;
56 if (padlen > 2)
57 memset(data+2, 0, data[1]);
58 }
59 return data + padlen;
60 }
61
62 static inline void mip6_param_prob(struct sk_buff *skb, int code, int pos)
63 {
64 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
65 }
66
67 static int mip6_mh_len(int type)
68 {
69 int len = 0;
70
71 switch (type) {
72 case IP6_MH_TYPE_BRR:
73 len = 0;
74 break;
75 case IP6_MH_TYPE_HOTI:
76 case IP6_MH_TYPE_COTI:
77 case IP6_MH_TYPE_BU:
78 case IP6_MH_TYPE_BACK:
79 len = 1;
80 break;
81 case IP6_MH_TYPE_HOT:
82 case IP6_MH_TYPE_COT:
83 case IP6_MH_TYPE_BERROR:
84 len = 2;
85 break;
86 }
87 return len;
88 }
89
90 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
91 {
92 struct ip6_mh *mh;
93
94 if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) ||
95 !pskb_may_pull(skb, (skb_transport_offset(skb) +
96 ((skb_transport_header(skb)[1] + 1) << 3))))
97 return -1;
98
99 mh = (struct ip6_mh *)skb_transport_header(skb);
100
101 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
102 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
103 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
104 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) -
105 skb_network_header(skb)));
106 return -1;
107 }
108
109 if (mh->ip6mh_proto != IPPROTO_NONE) {
110 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
111 mh->ip6mh_proto);
112 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) -
113 skb_network_header(skb)));
114 return -1;
115 }
116
117 return 0;
118 }
119
120 struct mip6_report_rate_limiter {
121 spinlock_t lock;
122 struct timeval stamp;
123 int iif;
124 struct in6_addr src;
125 struct in6_addr dst;
126 };
127
128 static struct mip6_report_rate_limiter mip6_report_rl = {
129 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
130 };
131
132 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
133 {
134 struct ipv6hdr *iph = ipv6_hdr(skb);
135 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
136
137 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
138 !ipv6_addr_any((struct in6_addr *)x->coaddr))
139 return -ENOENT;
140
141 return destopt->nexthdr;
142 }
143
144 /* Destination Option Header is inserted.
145 * IP Header's src address is replaced with Home Address Option in
146 * Destination Option Header.
147 */
148 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
149 {
150 struct ipv6hdr *iph;
151 struct ipv6_destopt_hdr *dstopt;
152 struct ipv6_destopt_hao *hao;
153 u8 nexthdr;
154 int len;
155
156 skb_push(skb, -skb_network_offset(skb));
157 iph = ipv6_hdr(skb);
158 iph->payload_len = htons(skb->len - sizeof(*iph));
159
160 nexthdr = *skb_mac_header(skb);
161 *skb_mac_header(skb) = IPPROTO_DSTOPTS;
162
163 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
164 dstopt->nexthdr = nexthdr;
165
166 hao = mip6_padn((char *)(dstopt + 1),
167 calc_padlen(sizeof(*dstopt), 6));
168
169 hao->type = IPV6_TLV_HAO;
170 hao->length = sizeof(*hao) - 2;
171 BUG_TRAP(hao->length == 16);
172
173 len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
174
175 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
176 spin_lock_bh(&x->lock);
177 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
178 spin_unlock_bh(&x->lock);
179
180 BUG_TRAP(len == x->props.header_len);
181 dstopt->hdrlen = (x->props.header_len >> 3) - 1;
182
183 return 0;
184 }
185
186 static inline int mip6_report_rl_allow(struct timeval *stamp,
187 struct in6_addr *dst,
188 struct in6_addr *src, int iif)
189 {
190 int allow = 0;
191
192 spin_lock_bh(&mip6_report_rl.lock);
193 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
194 mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
195 mip6_report_rl.iif != iif ||
196 !ipv6_addr_equal(&mip6_report_rl.src, src) ||
197 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
198 mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
199 mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
200 mip6_report_rl.iif = iif;
201 ipv6_addr_copy(&mip6_report_rl.src, src);
202 ipv6_addr_copy(&mip6_report_rl.dst, dst);
203 allow = 1;
204 }
205 spin_unlock_bh(&mip6_report_rl.lock);
206 return allow;
207 }
208
209 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl)
210 {
211 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
212 struct ipv6_destopt_hao *hao = NULL;
213 struct xfrm_selector sel;
214 int offset;
215 struct timeval stamp;
216 int err = 0;
217
218 if (unlikely(fl->proto == IPPROTO_MH &&
219 fl->fl_mh_type <= IP6_MH_TYPE_MAX))
220 goto out;
221
222 if (likely(opt->dsthao)) {
223 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
224 if (likely(offset >= 0))
225 hao = (struct ipv6_destopt_hao *)
226 (skb_network_header(skb) + offset);
227 }
228
229 skb_get_timestamp(skb, &stamp);
230
231 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
232 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
233 opt->iif))
234 goto out;
235
236 memset(&sel, 0, sizeof(sel));
237 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
238 sizeof(sel.daddr));
239 sel.prefixlen_d = 128;
240 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
241 sizeof(sel.saddr));
242 sel.prefixlen_s = 128;
243 sel.family = AF_INET6;
244 sel.proto = fl->proto;
245 sel.dport = xfrm_flowi_dport(fl);
246 if (sel.dport)
247 sel.dport_mask = htons(~0);
248 sel.sport = xfrm_flowi_sport(fl);
249 if (sel.sport)
250 sel.sport_mask = htons(~0);
251 sel.ifindex = fl->oif;
252
253 err = km_report(IPPROTO_DSTOPTS, &sel,
254 (hao ? (xfrm_address_t *)&hao->addr : NULL));
255
256 out:
257 return err;
258 }
259
260 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
261 u8 **nexthdr)
262 {
263 u16 offset = sizeof(struct ipv6hdr);
264 struct ipv6_opt_hdr *exthdr =
265 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
266 const unsigned char *nh = skb_network_header(skb);
267 unsigned int packet_len = skb->tail - skb->network_header;
268 int found_rhdr = 0;
269
270 *nexthdr = &ipv6_hdr(skb)->nexthdr;
271
272 while (offset + 1 <= packet_len) {
273
274 switch (**nexthdr) {
275 case NEXTHDR_HOP:
276 break;
277 case NEXTHDR_ROUTING:
278 found_rhdr = 1;
279 break;
280 case NEXTHDR_DEST:
281 /*
282 * HAO MUST NOT appear more than once.
283 * XXX: It is better to try to find by the end of
284 * XXX: packet if HAO exists.
285 */
286 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
287 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
288 return offset;
289 }
290
291 if (found_rhdr)
292 return offset;
293
294 break;
295 default:
296 return offset;
297 }
298
299 offset += ipv6_optlen(exthdr);
300 *nexthdr = &exthdr->nexthdr;
301 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
302 }
303
304 return offset;
305 }
306
307 static int mip6_destopt_init_state(struct xfrm_state *x)
308 {
309 if (x->id.spi) {
310 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
311 x->id.spi);
312 return -EINVAL;
313 }
314 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
315 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
316 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
317 return -EINVAL;
318 }
319
320 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
321 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
322 sizeof(struct ipv6_destopt_hao);
323 BUG_TRAP(x->props.header_len == 24);
324
325 return 0;
326 }
327
328 /*
329 * Do nothing about destroying since it has no specific operation for
330 * destination options header unlike IPsec protocols.
331 */
332 static void mip6_destopt_destroy(struct xfrm_state *x)
333 {
334 }
335
336 static struct xfrm_type mip6_destopt_type =
337 {
338 .description = "MIP6DESTOPT",
339 .owner = THIS_MODULE,
340 .proto = IPPROTO_DSTOPTS,
341 .flags = XFRM_TYPE_NON_FRAGMENT,
342 .init_state = mip6_destopt_init_state,
343 .destructor = mip6_destopt_destroy,
344 .input = mip6_destopt_input,
345 .output = mip6_destopt_output,
346 .reject = mip6_destopt_reject,
347 .hdr_offset = mip6_destopt_offset,
348 .local_addr = mip6_xfrm_addr,
349 };
350
351 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
352 {
353 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
354
355 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
356 !ipv6_addr_any((struct in6_addr *)x->coaddr))
357 return -ENOENT;
358
359 return rt2->rt_hdr.nexthdr;
360 }
361
362 /* Routing Header type 2 is inserted.
363 * IP Header's dst address is replaced with Routing Header's Home Address.
364 */
365 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
366 {
367 struct ipv6hdr *iph;
368 struct rt2_hdr *rt2;
369 u8 nexthdr;
370
371 skb_push(skb, -skb_network_offset(skb));
372 iph = ipv6_hdr(skb);
373 iph->payload_len = htons(skb->len - sizeof(*iph));
374
375 nexthdr = *skb_mac_header(skb);
376 *skb_mac_header(skb) = IPPROTO_ROUTING;
377
378 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
379 rt2->rt_hdr.nexthdr = nexthdr;
380 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
381 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
382 rt2->rt_hdr.segments_left = 1;
383 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
384
385 BUG_TRAP(rt2->rt_hdr.hdrlen == 2);
386
387 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
388 spin_lock_bh(&x->lock);
389 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
390 spin_unlock_bh(&x->lock);
391
392 return 0;
393 }
394
395 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
396 u8 **nexthdr)
397 {
398 u16 offset = sizeof(struct ipv6hdr);
399 struct ipv6_opt_hdr *exthdr =
400 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
401 const unsigned char *nh = skb_network_header(skb);
402 unsigned int packet_len = skb->tail - skb->network_header;
403 int found_rhdr = 0;
404
405 *nexthdr = &ipv6_hdr(skb)->nexthdr;
406
407 while (offset + 1 <= packet_len) {
408
409 switch (**nexthdr) {
410 case NEXTHDR_HOP:
411 break;
412 case NEXTHDR_ROUTING:
413 if (offset + 3 <= packet_len) {
414 struct ipv6_rt_hdr *rt;
415 rt = (struct ipv6_rt_hdr *)(nh + offset);
416 if (rt->type != 0)
417 return offset;
418 }
419 found_rhdr = 1;
420 break;
421 case NEXTHDR_DEST:
422 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
423 return offset;
424
425 if (found_rhdr)
426 return offset;
427
428 break;
429 default:
430 return offset;
431 }
432
433 offset += ipv6_optlen(exthdr);
434 *nexthdr = &exthdr->nexthdr;
435 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
436 }
437
438 return offset;
439 }
440
441 static int mip6_rthdr_init_state(struct xfrm_state *x)
442 {
443 if (x->id.spi) {
444 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
445 x->id.spi);
446 return -EINVAL;
447 }
448 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
449 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
450 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
451 return -EINVAL;
452 }
453
454 x->props.header_len = sizeof(struct rt2_hdr);
455
456 return 0;
457 }
458
459 /*
460 * Do nothing about destroying since it has no specific operation for routing
461 * header type 2 unlike IPsec protocols.
462 */
463 static void mip6_rthdr_destroy(struct xfrm_state *x)
464 {
465 }
466
467 static struct xfrm_type mip6_rthdr_type =
468 {
469 .description = "MIP6RT",
470 .owner = THIS_MODULE,
471 .proto = IPPROTO_ROUTING,
472 .flags = XFRM_TYPE_NON_FRAGMENT,
473 .init_state = mip6_rthdr_init_state,
474 .destructor = mip6_rthdr_destroy,
475 .input = mip6_rthdr_input,
476 .output = mip6_rthdr_output,
477 .hdr_offset = mip6_rthdr_offset,
478 .remote_addr = mip6_xfrm_addr,
479 };
480
481 static int __init mip6_init(void)
482 {
483 printk(KERN_INFO "Mobile IPv6\n");
484
485 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
486 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__);
487 goto mip6_destopt_xfrm_fail;
488 }
489 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
490 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__);
491 goto mip6_rthdr_xfrm_fail;
492 }
493 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
494 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __FUNCTION__);
495 goto mip6_rawv6_mh_fail;
496 }
497
498
499 return 0;
500
501 mip6_rawv6_mh_fail:
502 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
503 mip6_rthdr_xfrm_fail:
504 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
505 mip6_destopt_xfrm_fail:
506 return -EAGAIN;
507 }
508
509 static void __exit mip6_fini(void)
510 {
511 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
512 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __FUNCTION__);
513 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
514 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
515 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
516 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__);
517 }
518
519 module_init(mip6_init);
520 module_exit(mip6_fini);
521
522 MODULE_LICENSE("GPL");
523 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
524 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
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