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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / net / ipv6 / mip6.c
blobcd8a5bda13cd7a5caad4ac6c8280764e123cb7d7
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] = MIP6_OPT_PAD_1;
48 } else if (padlen > 1) {
49 data[0] = MIP6_OPT_PAD_N;
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, int code, int pos)
58 {
59 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
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 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 hao->length = sizeof(*hao) - 2;
168 BUG_TRAP(hao->length == 16);
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 BUG_TRAP(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 struct in6_addr *dst,
185 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, struct flowi *fl)
207 {
208 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
209 struct ipv6_destopt_hao *hao = NULL;
210 struct xfrm_selector sel;
211 int offset;
212 struct timeval stamp;
213 int err = 0;
214
215 if (unlikely(fl->proto == IPPROTO_MH &&
216 fl->fl_mh_type <= IP6_MH_TYPE_MAX))
217 goto out;
218
219 if (likely(opt->dsthao)) {
220 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
221 if (likely(offset >= 0))
222 hao = (struct ipv6_destopt_hao *)
223 (skb_network_header(skb) + offset);
224 }
225
226 skb_get_timestamp(skb, &stamp);
227
228 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
229 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
230 opt->iif))
231 goto out;
232
233 memset(&sel, 0, sizeof(sel));
234 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
235 sizeof(sel.daddr));
236 sel.prefixlen_d = 128;
237 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
238 sizeof(sel.saddr));
239 sel.prefixlen_s = 128;
240 sel.family = AF_INET6;
241 sel.proto = fl->proto;
242 sel.dport = xfrm_flowi_dport(fl);
243 if (sel.dport)
244 sel.dport_mask = htons(~0);
245 sel.sport = xfrm_flowi_sport(fl);
246 if (sel.sport)
247 sel.sport_mask = htons(~0);
248 sel.ifindex = fl->oif;
249
250 err = km_report(IPPROTO_DSTOPTS, &sel,
251 (hao ? (xfrm_address_t *)&hao->addr : NULL));
252
253 out:
254 return err;
255 }
256
257 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
258 u8 **nexthdr)
259 {
260 u16 offset = sizeof(struct ipv6hdr);
261 struct ipv6_opt_hdr *exthdr =
262 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
263 const unsigned char *nh = skb_network_header(skb);
264 unsigned int packet_len = skb->tail - skb->network_header;
265 int found_rhdr = 0;
266
267 *nexthdr = &ipv6_hdr(skb)->nexthdr;
268
269 while (offset + 1 <= packet_len) {
270
271 switch (**nexthdr) {
272 case NEXTHDR_HOP:
273 break;
274 case NEXTHDR_ROUTING:
275 found_rhdr = 1;
276 break;
277 case NEXTHDR_DEST:
278 /*
279 * HAO MUST NOT appear more than once.
280 * XXX: It is better to try to find by the end of
281 * XXX: packet if HAO exists.
282 */
283 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
284 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
285 return offset;
286 }
287
288 if (found_rhdr)
289 return offset;
290
291 break;
292 default:
293 return offset;
294 }
295
296 offset += ipv6_optlen(exthdr);
297 *nexthdr = &exthdr->nexthdr;
298 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
299 }
300
301 return offset;
302 }
303
304 static int mip6_destopt_init_state(struct xfrm_state *x)
305 {
306 if (x->id.spi) {
307 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
308 x->id.spi);
309 return -EINVAL;
310 }
311 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
312 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
313 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
314 return -EINVAL;
315 }
316
317 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
318 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
319 sizeof(struct ipv6_destopt_hao);
320 BUG_TRAP(x->props.header_len == 24);
321
322 return 0;
323 }
324
325 /*
326 * Do nothing about destroying since it has no specific operation for
327 * destination options header unlike IPsec protocols.
328 */
329 static void mip6_destopt_destroy(struct xfrm_state *x)
330 {
331 }
332
333 static const struct xfrm_type mip6_destopt_type =
334 {
335 .description = "MIP6DESTOPT",
336 .owner = THIS_MODULE,
337 .proto = IPPROTO_DSTOPTS,
338 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
339 .init_state = mip6_destopt_init_state,
340 .destructor = mip6_destopt_destroy,
341 .input = mip6_destopt_input,
342 .output = mip6_destopt_output,
343 .reject = mip6_destopt_reject,
344 .hdr_offset = mip6_destopt_offset,
345 };
346
347 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
348 {
349 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
350 int err = rt2->rt_hdr.nexthdr;
351
352 spin_lock(&x->lock);
353 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
354 !ipv6_addr_any((struct in6_addr *)x->coaddr))
355 err = -ENOENT;
356 spin_unlock(&x->lock);
357
358 return err;
359 }
360
361 /* Routing Header type 2 is inserted.
362 * IP Header's dst address is replaced with Routing Header's Home Address.
363 */
364 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
365 {
366 struct ipv6hdr *iph;
367 struct rt2_hdr *rt2;
368 u8 nexthdr;
369
370 skb_push(skb, -skb_network_offset(skb));
371 iph = ipv6_hdr(skb);
372
373 nexthdr = *skb_mac_header(skb);
374 *skb_mac_header(skb) = IPPROTO_ROUTING;
375
376 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
377 rt2->rt_hdr.nexthdr = nexthdr;
378 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
379 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
380 rt2->rt_hdr.segments_left = 1;
381 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
382
383 BUG_TRAP(rt2->rt_hdr.hdrlen == 2);
384
385 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
386 spin_lock_bh(&x->lock);
387 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
388 spin_unlock_bh(&x->lock);
389
390 return 0;
391 }
392
393 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
394 u8 **nexthdr)
395 {
396 u16 offset = sizeof(struct ipv6hdr);
397 struct ipv6_opt_hdr *exthdr =
398 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
399 const unsigned char *nh = skb_network_header(skb);
400 unsigned int packet_len = skb->tail - skb->network_header;
401 int found_rhdr = 0;
402
403 *nexthdr = &ipv6_hdr(skb)->nexthdr;
404
405 while (offset + 1 <= packet_len) {
406
407 switch (**nexthdr) {
408 case NEXTHDR_HOP:
409 break;
410 case NEXTHDR_ROUTING:
411 if (offset + 3 <= packet_len) {
412 struct ipv6_rt_hdr *rt;
413 rt = (struct ipv6_rt_hdr *)(nh + offset);
414 if (rt->type != 0)
415 return offset;
416 }
417 found_rhdr = 1;
418 break;
419 case NEXTHDR_DEST:
420 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
421 return offset;
422
423 if (found_rhdr)
424 return offset;
425
426 break;
427 default:
428 return offset;
429 }
430
431 offset += ipv6_optlen(exthdr);
432 *nexthdr = &exthdr->nexthdr;
433 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
434 }
435
436 return offset;
437 }
438
439 static int mip6_rthdr_init_state(struct xfrm_state *x)
440 {
441 if (x->id.spi) {
442 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
443 x->id.spi);
444 return -EINVAL;
445 }
446 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
447 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
448 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
449 return -EINVAL;
450 }
451
452 x->props.header_len = sizeof(struct rt2_hdr);
453
454 return 0;
455 }
456
457 /*
458 * Do nothing about destroying since it has no specific operation for routing
459 * header type 2 unlike IPsec protocols.
460 */
461 static void mip6_rthdr_destroy(struct xfrm_state *x)
462 {
463 }
464
465 static const struct xfrm_type mip6_rthdr_type =
466 {
467 .description = "MIP6RT",
468 .owner = THIS_MODULE,
469 .proto = IPPROTO_ROUTING,
470 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
471 .init_state = mip6_rthdr_init_state,
472 .destructor = mip6_rthdr_destroy,
473 .input = mip6_rthdr_input,
474 .output = mip6_rthdr_output,
475 .hdr_offset = mip6_rthdr_offset,
476 };
477
478 static int __init mip6_init(void)
479 {
480 printk(KERN_INFO "Mobile IPv6\n");
481
482 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
483 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__);
484 goto mip6_destopt_xfrm_fail;
485 }
486 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
487 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__);
488 goto mip6_rthdr_xfrm_fail;
489 }
490 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
491 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __FUNCTION__);
492 goto mip6_rawv6_mh_fail;
493 }
494
495
496 return 0;
497
498 mip6_rawv6_mh_fail:
499 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
500 mip6_rthdr_xfrm_fail:
501 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
502 mip6_destopt_xfrm_fail:
503 return -EAGAIN;
504 }
505
506 static void __exit mip6_fini(void)
507 {
508 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
509 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __FUNCTION__);
510 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
511 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
512 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
513 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__);
514 }
515
516 module_init(mip6_init);
517 module_exit(mip6_fini);
518
519 MODULE_LICENSE("GPL");
520 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
521 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
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