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24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/module.h>
27#include <linux/skbuff.h>
28#include <linux/time.h>
29#include <linux/ipv6.h>
30#include <linux/icmpv6.h>
31#include <net/sock.h>
32#include <net/ipv6.h>
33#include <net/ip6_checksum.h>
34#include <net/rawv6.h>
35#include <net/xfrm.h>
36#include <net/mip6.h>
37
38static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
39{
40 return (n - len + 16) & 0x7;
41}
42
43static inline void *mip6_padn(__u8 *data, __u8 padlen)
44{
45 if (!data)
46 return NULL;
47 if (padlen == 1) {
48 data[0] = IPV6_TLV_PAD1;
49 } else if (padlen > 1) {
50 data[0] = IPV6_TLV_PADN;
51 data[1] = padlen - 2;
52 if (padlen > 2)
53 memset(data+2, 0, data[1]);
54 }
55 return data + padlen;
56}
57
58static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
59{
60 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
61}
62
63static int mip6_mh_len(int type)
64{
65 int len = 0;
66
67 switch (type) {
68 case IP6_MH_TYPE_BRR:
69 len = 0;
70 break;
71 case IP6_MH_TYPE_HOTI:
72 case IP6_MH_TYPE_COTI:
73 case IP6_MH_TYPE_BU:
74 case IP6_MH_TYPE_BACK:
75 len = 1;
76 break;
77 case IP6_MH_TYPE_HOT:
78 case IP6_MH_TYPE_COT:
79 case IP6_MH_TYPE_BERROR:
80 len = 2;
81 break;
82 }
83 return len;
84}
85
86static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
87{
88 struct ip6_mh _hdr;
89 const struct ip6_mh *mh;
90
91 mh = skb_header_pointer(skb, skb_transport_offset(skb),
92 sizeof(_hdr), &_hdr);
93 if (!mh)
94 return -1;
95
96 if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len)
97 return -1;
98
99 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
100 net_dbg_ratelimited("mip6: MH message too short: %d vs >=%d\n",
101 mh->ip6mh_hdrlen,
102 mip6_mh_len(mh->ip6mh_type));
103 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) +
104 skb_network_header_len(skb));
105 return -1;
106 }
107
108 if (mh->ip6mh_proto != IPPROTO_NONE) {
109 net_dbg_ratelimited("mip6: MH invalid payload proto = %d\n",
110 mh->ip6mh_proto);
111 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) +
112 skb_network_header_len(skb));
113 return -1;
114 }
115
116 return 0;
117}
118
119struct mip6_report_rate_limiter {
120 spinlock_t lock;
121 struct timeval stamp;
122 int iif;
123 struct in6_addr src;
124 struct in6_addr dst;
125};
126
127static struct mip6_report_rate_limiter mip6_report_rl = {
128 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
129};
130
131static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
132{
133 const struct ipv6hdr *iph = ipv6_hdr(skb);
134 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
135 int err = destopt->nexthdr;
136
137 spin_lock(&x->lock);
138 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
139 !ipv6_addr_any((struct in6_addr *)x->coaddr))
140 err = -ENOENT;
141 spin_unlock(&x->lock);
142
143 return err;
144}
145
146
147
148
149
150static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
151{
152 struct ipv6hdr *iph;
153 struct ipv6_destopt_hdr *dstopt;
154 struct ipv6_destopt_hao *hao;
155 u8 nexthdr;
156 int len;
157
158 skb_push(skb, -skb_network_offset(skb));
159 iph = ipv6_hdr(skb);
160
161 nexthdr = *skb_mac_header(skb);
162 *skb_mac_header(skb) = IPPROTO_DSTOPTS;
163
164 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
165 dstopt->nexthdr = nexthdr;
166
167 hao = mip6_padn((char *)(dstopt + 1),
168 calc_padlen(sizeof(*dstopt), 6));
169
170 hao->type = IPV6_TLV_HAO;
171 BUILD_BUG_ON(sizeof(*hao) != 18);
172 hao->length = sizeof(*hao) - 2;
173
174 len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
175
176 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
177 spin_lock_bh(&x->lock);
178 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
179 spin_unlock_bh(&x->lock);
180
181 WARN_ON(len != x->props.header_len);
182 dstopt->hdrlen = (x->props.header_len >> 3) - 1;
183
184 return 0;
185}
186
187static inline int mip6_report_rl_allow(struct timeval *stamp,
188 const struct in6_addr *dst,
189 const struct in6_addr *src, int iif)
190{
191 int allow = 0;
192
193 spin_lock_bh(&mip6_report_rl.lock);
194 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
195 mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
196 mip6_report_rl.iif != iif ||
197 !ipv6_addr_equal(&mip6_report_rl.src, src) ||
198 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
199 mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
200 mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
201 mip6_report_rl.iif = iif;
202 mip6_report_rl.src = *src;
203 mip6_report_rl.dst = *dst;
204 allow = 1;
205 }
206 spin_unlock_bh(&mip6_report_rl.lock);
207 return allow;
208}
209
210static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
211 const struct flowi *fl)
212{
213 struct net *net = xs_net(x);
214 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
215 const struct flowi6 *fl6 = &fl->u.ip6;
216 struct ipv6_destopt_hao *hao = NULL;
217 struct xfrm_selector sel;
218 int offset;
219 struct timeval stamp;
220 int err = 0;
221
222 if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
223 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
224 goto out;
225
226 if (likely(opt->dsthao)) {
227 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
228 if (likely(offset >= 0))
229 hao = (struct ipv6_destopt_hao *)
230 (skb_network_header(skb) + offset);
231 }
232
233 skb_get_timestamp(skb, &stamp);
234
235 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
236 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
237 opt->iif))
238 goto out;
239
240 memset(&sel, 0, sizeof(sel));
241 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
242 sizeof(sel.daddr));
243 sel.prefixlen_d = 128;
244 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
245 sizeof(sel.saddr));
246 sel.prefixlen_s = 128;
247 sel.family = AF_INET6;
248 sel.proto = fl6->flowi6_proto;
249 sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
250 if (sel.dport)
251 sel.dport_mask = htons(~0);
252 sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
253 if (sel.sport)
254 sel.sport_mask = htons(~0);
255 sel.ifindex = fl6->flowi6_oif;
256
257 err = km_report(net, IPPROTO_DSTOPTS, &sel,
258 (hao ? (xfrm_address_t *)&hao->addr : NULL));
259
260 out:
261 return err;
262}
263
264static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
265 u8 **nexthdr)
266{
267 u16 offset = sizeof(struct ipv6hdr);
268 struct ipv6_opt_hdr *exthdr =
269 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
270 const unsigned char *nh = skb_network_header(skb);
271 unsigned int packet_len = skb_tail_pointer(skb) -
272 skb_network_header(skb);
273 int found_rhdr = 0;
274
275 *nexthdr = &ipv6_hdr(skb)->nexthdr;
276
277 while (offset + 1 <= packet_len) {
278
279 switch (**nexthdr) {
280 case NEXTHDR_HOP:
281 break;
282 case NEXTHDR_ROUTING:
283 found_rhdr = 1;
284 break;
285 case NEXTHDR_DEST:
286
287
288
289
290
291 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
292 net_dbg_ratelimited("mip6: hao exists already, override\n");
293 return offset;
294 }
295
296 if (found_rhdr)
297 return offset;
298
299 break;
300 default:
301 return offset;
302 }
303
304 offset += ipv6_optlen(exthdr);
305 *nexthdr = &exthdr->nexthdr;
306 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
307 }
308
309 return offset;
310}
311
312static int mip6_destopt_init_state(struct xfrm_state *x)
313{
314 if (x->id.spi) {
315 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
316 return -EINVAL;
317 }
318 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
319 pr_info("%s: state's mode is not %u: %u\n",
320 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
321 return -EINVAL;
322 }
323
324 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
325 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
326 sizeof(struct ipv6_destopt_hao);
327 WARN_ON(x->props.header_len != 24);
328
329 return 0;
330}
331
332
333
334
335
336static void mip6_destopt_destroy(struct xfrm_state *x)
337{
338}
339
340static const struct xfrm_type mip6_destopt_type = {
341 .description = "MIP6DESTOPT",
342 .owner = THIS_MODULE,
343 .proto = IPPROTO_DSTOPTS,
344 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
345 .init_state = mip6_destopt_init_state,
346 .destructor = mip6_destopt_destroy,
347 .input = mip6_destopt_input,
348 .output = mip6_destopt_output,
349 .reject = mip6_destopt_reject,
350 .hdr_offset = mip6_destopt_offset,
351};
352
353static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
354{
355 const struct ipv6hdr *iph = ipv6_hdr(skb);
356 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
357 int err = rt2->rt_hdr.nexthdr;
358
359 spin_lock(&x->lock);
360 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
361 !ipv6_addr_any((struct in6_addr *)x->coaddr))
362 err = -ENOENT;
363 spin_unlock(&x->lock);
364
365 return err;
366}
367
368
369
370
371static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
372{
373 struct ipv6hdr *iph;
374 struct rt2_hdr *rt2;
375 u8 nexthdr;
376
377 skb_push(skb, -skb_network_offset(skb));
378 iph = ipv6_hdr(skb);
379
380 nexthdr = *skb_mac_header(skb);
381 *skb_mac_header(skb) = IPPROTO_ROUTING;
382
383 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
384 rt2->rt_hdr.nexthdr = nexthdr;
385 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
386 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
387 rt2->rt_hdr.segments_left = 1;
388 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
389
390 WARN_ON(rt2->rt_hdr.hdrlen != 2);
391
392 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
393 spin_lock_bh(&x->lock);
394 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
395 spin_unlock_bh(&x->lock);
396
397 return 0;
398}
399
400static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
401 u8 **nexthdr)
402{
403 u16 offset = sizeof(struct ipv6hdr);
404 struct ipv6_opt_hdr *exthdr =
405 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
406 const unsigned char *nh = skb_network_header(skb);
407 unsigned int packet_len = skb_tail_pointer(skb) -
408 skb_network_header(skb);
409 int found_rhdr = 0;
410
411 *nexthdr = &ipv6_hdr(skb)->nexthdr;
412
413 while (offset + 1 <= packet_len) {
414
415 switch (**nexthdr) {
416 case NEXTHDR_HOP:
417 break;
418 case NEXTHDR_ROUTING:
419 if (offset + 3 <= packet_len) {
420 struct ipv6_rt_hdr *rt;
421 rt = (struct ipv6_rt_hdr *)(nh + offset);
422 if (rt->type != 0)
423 return offset;
424 }
425 found_rhdr = 1;
426 break;
427 case NEXTHDR_DEST:
428 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
429 return offset;
430
431 if (found_rhdr)
432 return offset;
433
434 break;
435 default:
436 return offset;
437 }
438
439 offset += ipv6_optlen(exthdr);
440 *nexthdr = &exthdr->nexthdr;
441 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
442 }
443
444 return offset;
445}
446
447static int mip6_rthdr_init_state(struct xfrm_state *x)
448{
449 if (x->id.spi) {
450 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
451 return -EINVAL;
452 }
453 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
454 pr_info("%s: state's mode is not %u: %u\n",
455 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
456 return -EINVAL;
457 }
458
459 x->props.header_len = sizeof(struct rt2_hdr);
460
461 return 0;
462}
463
464
465
466
467
468static void mip6_rthdr_destroy(struct xfrm_state *x)
469{
470}
471
472static const struct xfrm_type mip6_rthdr_type = {
473 .description = "MIP6RT",
474 .owner = THIS_MODULE,
475 .proto = IPPROTO_ROUTING,
476 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
477 .init_state = mip6_rthdr_init_state,
478 .destructor = mip6_rthdr_destroy,
479 .input = mip6_rthdr_input,
480 .output = mip6_rthdr_output,
481 .hdr_offset = mip6_rthdr_offset,
482};
483
484static int __init mip6_init(void)
485{
486 pr_info("Mobile IPv6\n");
487
488 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
489 pr_info("%s: can't add xfrm type(destopt)\n", __func__);
490 goto mip6_destopt_xfrm_fail;
491 }
492 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
493 pr_info("%s: can't add xfrm type(rthdr)\n", __func__);
494 goto mip6_rthdr_xfrm_fail;
495 }
496 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
497 pr_info("%s: can't add rawv6 mh filter\n", __func__);
498 goto mip6_rawv6_mh_fail;
499 }
500
501
502 return 0;
503
504 mip6_rawv6_mh_fail:
505 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
506 mip6_rthdr_xfrm_fail:
507 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
508 mip6_destopt_xfrm_fail:
509 return -EAGAIN;
510}
511
512static void __exit mip6_fini(void)
513{
514 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
515 pr_info("%s: can't remove rawv6 mh filter\n", __func__);
516 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
517 pr_info("%s: can't remove xfrm type(rthdr)\n", __func__);
518 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
519 pr_info("%s: can't remove xfrm type(destopt)\n", __func__);
520}
521
522module_init(mip6_init);
523module_exit(mip6_fini);
524
525MODULE_LICENSE("GPL");
526MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
527MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
528
