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Merge remote-tracking branch 'sysctl/master'
[linux-2.6/next.git] / net / ipv6 / mip6.c
blob43242e6e610301c2a662932f3f910ab6ed6e573d
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 inline unsigned int calc_padlen(unsigned int len, unsigned int n)
38 {
39 return (n - len + 16) & 0x7;
40 }
41
42 static inline void *mip6_padn(__u8 *data, __u8 padlen)
43 {
44 if (!data)
45 return NULL;
46 if (padlen == 1) {
47 data[0] = IPV6_TLV_PAD0;
48 } else if (padlen > 1) {
49 data[0] = IPV6_TLV_PADN;
50 data[1] = padlen - 2;
51 if (padlen > 2)
52 memset(data+2, 0, data[1]);
53 }
54 return data + padlen;
55 }
56
57 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
58 {
59 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
60 }
61
62 static int mip6_mh_len(int type)
63 {
64 int len = 0;
65
66 switch (type) {
67 case IP6_MH_TYPE_BRR:
68 len = 0;
69 break;
70 case IP6_MH_TYPE_HOTI:
71 case IP6_MH_TYPE_COTI:
72 case IP6_MH_TYPE_BU:
73 case IP6_MH_TYPE_BACK:
74 len = 1;
75 break;
76 case IP6_MH_TYPE_HOT:
77 case IP6_MH_TYPE_COT:
78 case IP6_MH_TYPE_BERROR:
79 len = 2;
80 break;
81 }
82 return len;
83 }
84
85 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
86 {
87 struct ip6_mh *mh;
88
89 if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) ||
90 !pskb_may_pull(skb, (skb_transport_offset(skb) +
91 ((skb_transport_header(skb)[1] + 1) << 3))))
92 return -1;
93
94 mh = (struct ip6_mh *)skb_transport_header(skb);
95
96 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
97 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
98 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
99 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) -
100 skb_network_header(skb)));
101 return -1;
102 }
103
104 if (mh->ip6mh_proto != IPPROTO_NONE) {
105 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
106 mh->ip6mh_proto);
107 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) -
108 skb_network_header(skb)));
109 return -1;
110 }
111
112 return 0;
113 }
114
115 struct mip6_report_rate_limiter {
116 spinlock_t lock;
117 struct timeval stamp;
118 int iif;
119 struct in6_addr src;
120 struct in6_addr dst;
121 };
122
123 static struct mip6_report_rate_limiter mip6_report_rl = {
124 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
125 };
126
127 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
128 {
129 const struct ipv6hdr *iph = ipv6_hdr(skb);
130 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
131 int err = destopt->nexthdr;
132
133 spin_lock(&x->lock);
134 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
135 !ipv6_addr_any((struct in6_addr *)x->coaddr))
136 err = -ENOENT;
137 spin_unlock(&x->lock);
138
139 return err;
140 }
141
142 /* Destination Option Header is inserted.
143 * IP Header's src address is replaced with Home Address Option in
144 * Destination Option Header.
145 */
146 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
147 {
148 struct ipv6hdr *iph;
149 struct ipv6_destopt_hdr *dstopt;
150 struct ipv6_destopt_hao *hao;
151 u8 nexthdr;
152 int len;
153
154 skb_push(skb, -skb_network_offset(skb));
155 iph = ipv6_hdr(skb);
156
157 nexthdr = *skb_mac_header(skb);
158 *skb_mac_header(skb) = IPPROTO_DSTOPTS;
159
160 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
161 dstopt->nexthdr = nexthdr;
162
163 hao = mip6_padn((char *)(dstopt + 1),
164 calc_padlen(sizeof(*dstopt), 6));
165
166 hao->type = IPV6_TLV_HAO;
167 BUILD_BUG_ON(sizeof(*hao) != 18);
168 hao->length = sizeof(*hao) - 2;
169
170 len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
171
172 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
173 spin_lock_bh(&x->lock);
174 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
175 spin_unlock_bh(&x->lock);
176
177 WARN_ON(len != x->props.header_len);
178 dstopt->hdrlen = (x->props.header_len >> 3) - 1;
179
180 return 0;
181 }
182
183 static inline int mip6_report_rl_allow(struct timeval *stamp,
184 const struct in6_addr *dst,
185 const struct in6_addr *src, int iif)
186 {
187 int allow = 0;
188
189 spin_lock_bh(&mip6_report_rl.lock);
190 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
191 mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
192 mip6_report_rl.iif != iif ||
193 !ipv6_addr_equal(&mip6_report_rl.src, src) ||
194 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
195 mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
196 mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
197 mip6_report_rl.iif = iif;
198 ipv6_addr_copy(&mip6_report_rl.src, src);
199 ipv6_addr_copy(&mip6_report_rl.dst, dst);
200 allow = 1;
201 }
202 spin_unlock_bh(&mip6_report_rl.lock);
203 return allow;
204 }
205
206 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
207 const struct flowi *fl)
208 {
209 struct net *net = xs_net(x);
210 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
211 const struct flowi6 *fl6 = &fl->u.ip6;
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(fl6->flowi6_proto == IPPROTO_MH &&
219 fl6->fl6_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 = fl6->flowi6_proto;
245 sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
246 if (sel.dport)
247 sel.dport_mask = htons(~0);
248 sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
249 if (sel.sport)
250 sel.sport_mask = htons(~0);
251 sel.ifindex = fl6->flowi6_oif;
252
253 err = km_report(net, 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", __func__,
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 __func__, 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 WARN_ON(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 const struct xfrm_type mip6_destopt_type =
337 {
338 .description = "MIP6DESTOPT",
339 .owner = THIS_MODULE,
340 .proto = IPPROTO_DSTOPTS,
341 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
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 };
349
350 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
351 {
352 const struct ipv6hdr *iph = ipv6_hdr(skb);
353 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
354 int err = rt2->rt_hdr.nexthdr;
355
356 spin_lock(&x->lock);
357 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
358 !ipv6_addr_any((struct in6_addr *)x->coaddr))
359 err = -ENOENT;
360 spin_unlock(&x->lock);
361
362 return err;
363 }
364
365 /* Routing Header type 2 is inserted.
366 * IP Header's dst address is replaced with Routing Header's Home Address.
367 */
368 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
369 {
370 struct ipv6hdr *iph;
371 struct rt2_hdr *rt2;
372 u8 nexthdr;
373
374 skb_push(skb, -skb_network_offset(skb));
375 iph = ipv6_hdr(skb);
376
377 nexthdr = *skb_mac_header(skb);
378 *skb_mac_header(skb) = IPPROTO_ROUTING;
379
380 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
381 rt2->rt_hdr.nexthdr = nexthdr;
382 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
383 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
384 rt2->rt_hdr.segments_left = 1;
385 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
386
387 WARN_ON(rt2->rt_hdr.hdrlen != 2);
388
389 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
390 spin_lock_bh(&x->lock);
391 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
392 spin_unlock_bh(&x->lock);
393
394 return 0;
395 }
396
397 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
398 u8 **nexthdr)
399 {
400 u16 offset = sizeof(struct ipv6hdr);
401 struct ipv6_opt_hdr *exthdr =
402 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
403 const unsigned char *nh = skb_network_header(skb);
404 unsigned int packet_len = skb->tail - skb->network_header;
405 int found_rhdr = 0;
406
407 *nexthdr = &ipv6_hdr(skb)->nexthdr;
408
409 while (offset + 1 <= packet_len) {
410
411 switch (**nexthdr) {
412 case NEXTHDR_HOP:
413 break;
414 case NEXTHDR_ROUTING:
415 if (offset + 3 <= packet_len) {
416 struct ipv6_rt_hdr *rt;
417 rt = (struct ipv6_rt_hdr *)(nh + offset);
418 if (rt->type != 0)
419 return offset;
420 }
421 found_rhdr = 1;
422 break;
423 case NEXTHDR_DEST:
424 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
425 return offset;
426
427 if (found_rhdr)
428 return offset;
429
430 break;
431 default:
432 return offset;
433 }
434
435 offset += ipv6_optlen(exthdr);
436 *nexthdr = &exthdr->nexthdr;
437 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
438 }
439
440 return offset;
441 }
442
443 static int mip6_rthdr_init_state(struct xfrm_state *x)
444 {
445 if (x->id.spi) {
446 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
447 x->id.spi);
448 return -EINVAL;
449 }
450 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
451 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
452 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
453 return -EINVAL;
454 }
455
456 x->props.header_len = sizeof(struct rt2_hdr);
457
458 return 0;
459 }
460
461 /*
462 * Do nothing about destroying since it has no specific operation for routing
463 * header type 2 unlike IPsec protocols.
464 */
465 static void mip6_rthdr_destroy(struct xfrm_state *x)
466 {
467 }
468
469 static const struct xfrm_type mip6_rthdr_type =
470 {
471 .description = "MIP6RT",
472 .owner = THIS_MODULE,
473 .proto = IPPROTO_ROUTING,
474 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
475 .init_state = mip6_rthdr_init_state,
476 .destructor = mip6_rthdr_destroy,
477 .input = mip6_rthdr_input,
478 .output = mip6_rthdr_output,
479 .hdr_offset = mip6_rthdr_offset,
480 };
481
482 static int __init mip6_init(void)
483 {
484 printk(KERN_INFO "Mobile IPv6\n");
485
486 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
487 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __func__);
488 goto mip6_destopt_xfrm_fail;
489 }
490 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
491 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __func__);
492 goto mip6_rthdr_xfrm_fail;
493 }
494 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
495 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __func__);
496 goto mip6_rawv6_mh_fail;
497 }
498
499
500 return 0;
501
502 mip6_rawv6_mh_fail:
503 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
504 mip6_rthdr_xfrm_fail:
505 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
506 mip6_destopt_xfrm_fail:
507 return -EAGAIN;
508 }
509
510 static void __exit mip6_fini(void)
511 {
512 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
513 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__);
514 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
515 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__);
516 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
517 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__);
518 }
519
520 module_init(mip6_init);
521 module_exit(mip6_fini);
522
523 MODULE_LICENSE("GPL");
524 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
525 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
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