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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 ktime_t 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(ktime_t 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 != stamp ||
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 = stamp;
199 mip6_report_rl.iif = iif;
200 mip6_report_rl.src = *src;
201 mip6_report_rl.dst = *dst;
202 allow = 1;
203 }
204 spin_unlock_bh(&mip6_report_rl.lock);
205 return allow;
206}
207
208static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
209 const struct flowi *fl)
210{
211 struct net *net = xs_net(x);
212 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
213 const struct flowi6 *fl6 = &fl->u.ip6;
214 struct ipv6_destopt_hao *hao = NULL;
215 struct xfrm_selector sel;
216 int offset;
217 ktime_t stamp;
218 int err = 0;
219
220 if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
221 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
222 goto out;
223
224 if (likely(opt->dsthao)) {
225 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
226 if (likely(offset >= 0))
227 hao = (struct ipv6_destopt_hao *)
228 (skb_network_header(skb) + offset);
229 }
230
231 stamp = skb_get_ktime(skb);
232
233 if (!mip6_report_rl_allow(stamp, &ipv6_hdr(skb)->daddr,
234 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
235 opt->iif))
236 goto out;
237
238 memset(&sel, 0, sizeof(sel));
239 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
240 sizeof(sel.daddr));
241 sel.prefixlen_d = 128;
242 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
243 sizeof(sel.saddr));
244 sel.prefixlen_s = 128;
245 sel.family = AF_INET6;
246 sel.proto = fl6->flowi6_proto;
247 sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
248 if (sel.dport)
249 sel.dport_mask = htons(~0);
250 sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
251 if (sel.sport)
252 sel.sport_mask = htons(~0);
253 sel.ifindex = fl6->flowi6_oif;
254
255 err = km_report(net, IPPROTO_DSTOPTS, &sel,
256 (hao ? (xfrm_address_t *)&hao->addr : NULL));
257
258 out:
259 return err;
260}
261
262static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
263 u8 **nexthdr)
264{
265 u16 offset = sizeof(struct ipv6hdr);
266 struct ipv6_opt_hdr *exthdr =
267 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
268 const unsigned char *nh = skb_network_header(skb);
269 unsigned int packet_len = skb_tail_pointer(skb) -
270 skb_network_header(skb);
271 int found_rhdr = 0;
272
273 *nexthdr = &ipv6_hdr(skb)->nexthdr;
274
275 while (offset + 1 <= packet_len) {
276
277 switch (**nexthdr) {
278 case NEXTHDR_HOP:
279 break;
280 case NEXTHDR_ROUTING:
281 found_rhdr = 1;
282 break;
283 case NEXTHDR_DEST:
284
285
286
287
288
289 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
290 net_dbg_ratelimited("mip6: hao exists already, override\n");
291 return offset;
292 }
293
294 if (found_rhdr)
295 return offset;
296
297 break;
298 default:
299 return offset;
300 }
301
302 offset += ipv6_optlen(exthdr);
303 *nexthdr = &exthdr->nexthdr;
304 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
305 }
306
307 return offset;
308}
309
310static int mip6_destopt_init_state(struct xfrm_state *x)
311{
312 if (x->id.spi) {
313 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
314 return -EINVAL;
315 }
316 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
317 pr_info("%s: state's mode is not %u: %u\n",
318 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
319 return -EINVAL;
320 }
321
322 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
323 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
324 sizeof(struct ipv6_destopt_hao);
325 WARN_ON(x->props.header_len != 24);
326
327 return 0;
328}
329
330
331
332
333
334static void mip6_destopt_destroy(struct xfrm_state *x)
335{
336}
337
338static const struct xfrm_type mip6_destopt_type = {
339 .description = "MIP6DESTOPT",
340 .owner = THIS_MODULE,
341 .proto = IPPROTO_DSTOPTS,
342 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
343 .init_state = mip6_destopt_init_state,
344 .destructor = mip6_destopt_destroy,
345 .input = mip6_destopt_input,
346 .output = mip6_destopt_output,
347 .reject = mip6_destopt_reject,
348 .hdr_offset = mip6_destopt_offset,
349};
350
351static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
352{
353 const struct ipv6hdr *iph = ipv6_hdr(skb);
354 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
355 int err = rt2->rt_hdr.nexthdr;
356
357 spin_lock(&x->lock);
358 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
359 !ipv6_addr_any((struct in6_addr *)x->coaddr))
360 err = -ENOENT;
361 spin_unlock(&x->lock);
362
363 return err;
364}
365
366
367
368
369static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
370{
371 struct ipv6hdr *iph;
372 struct rt2_hdr *rt2;
373 u8 nexthdr;
374
375 skb_push(skb, -skb_network_offset(skb));
376 iph = ipv6_hdr(skb);
377
378 nexthdr = *skb_mac_header(skb);
379 *skb_mac_header(skb) = IPPROTO_ROUTING;
380
381 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
382 rt2->rt_hdr.nexthdr = nexthdr;
383 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
384 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
385 rt2->rt_hdr.segments_left = 1;
386 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
387
388 WARN_ON(rt2->rt_hdr.hdrlen != 2);
389
390 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
391 spin_lock_bh(&x->lock);
392 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
393 spin_unlock_bh(&x->lock);
394
395 return 0;
396}
397
398static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
399 u8 **nexthdr)
400{
401 u16 offset = sizeof(struct ipv6hdr);
402 struct ipv6_opt_hdr *exthdr =
403 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
404 const unsigned char *nh = skb_network_header(skb);
405 unsigned int packet_len = skb_tail_pointer(skb) -
406 skb_network_header(skb);
407 int found_rhdr = 0;
408
409 *nexthdr = &ipv6_hdr(skb)->nexthdr;
410
411 while (offset + 1 <= packet_len) {
412
413 switch (**nexthdr) {
414 case NEXTHDR_HOP:
415 break;
416 case NEXTHDR_ROUTING:
417 if (offset + 3 <= packet_len) {
418 struct ipv6_rt_hdr *rt;
419 rt = (struct ipv6_rt_hdr *)(nh + offset);
420 if (rt->type != 0)
421 return offset;
422 }
423 found_rhdr = 1;
424 break;
425 case NEXTHDR_DEST:
426 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
427 return offset;
428
429 if (found_rhdr)
430 return offset;
431
432 break;
433 default:
434 return offset;
435 }
436
437 offset += ipv6_optlen(exthdr);
438 *nexthdr = &exthdr->nexthdr;
439 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
440 }
441
442 return offset;
443}
444
445static int mip6_rthdr_init_state(struct xfrm_state *x)
446{
447 if (x->id.spi) {
448 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
449 return -EINVAL;
450 }
451 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
452 pr_info("%s: state's mode is not %u: %u\n",
453 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
454 return -EINVAL;
455 }
456
457 x->props.header_len = sizeof(struct rt2_hdr);
458
459 return 0;
460}
461
462
463
464
465
466static void mip6_rthdr_destroy(struct xfrm_state *x)
467{
468}
469
470static const struct xfrm_type mip6_rthdr_type = {
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
482static int __init mip6_init(void)
483{
484 pr_info("Mobile IPv6\n");
485
486 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
487 pr_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 pr_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 pr_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
510static void __exit mip6_fini(void)
511{
512 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
513 pr_info("%s: can't remove rawv6 mh filter\n", __func__);
514 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
515 pr_info("%s: can't remove xfrm type(rthdr)\n", __func__);
516 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
517 pr_info("%s: can't remove xfrm type(destopt)\n", __func__);
518}
519
520module_init(mip6_init);
521module_exit(mip6_fini);
522
523MODULE_LICENSE("GPL");
524MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
525MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
526
