1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C)2003-2006 Helsinki University of Technology
4 * Copyright (C)2003-2006 USAGI/WIDE Project
5 */
6 /*
7 * Authors:
8 * Noriaki TAKAMIYA @USAGI
9 * Masahide NAKAMURA @USAGI
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/time.h>
17 #include <linux/ipv6.h>
18 #include <linux/icmpv6.h>
19 #include <net/sock.h>
20 #include <net/ipv6.h>
21 #include <net/ip6_checksum.h>
22 #include <net/rawv6.h>
23 #include <net/xfrm.h>
24 #include <net/mip6.h>
25
calc_padlen(unsigned int len,unsigned int n)26 static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
27 {
28 return (n - len + 16) & 0x7;
29 }
30
mip6_padn(__u8 * data,__u8 padlen)31 static inline void *mip6_padn(__u8 *data, __u8 padlen)
32 {
33 if (!data)
34 return NULL;
35 if (padlen == 1) {
36 data[0] = IPV6_TLV_PAD1;
37 } else if (padlen > 1) {
38 data[0] = IPV6_TLV_PADN;
39 data[1] = padlen - 2;
40 if (padlen > 2)
41 memset(data+2, 0, data[1]);
42 }
43 return data + padlen;
44 }
45
mip6_param_prob(struct sk_buff * skb,u8 code,int pos)46 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
47 {
48 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
49 }
50
mip6_mh_len(int type)51 static int mip6_mh_len(int type)
52 {
53 int len = 0;
54
55 switch (type) {
56 case IP6_MH_TYPE_BRR:
57 len = 0;
58 break;
59 case IP6_MH_TYPE_HOTI:
60 case IP6_MH_TYPE_COTI:
61 case IP6_MH_TYPE_BU:
62 case IP6_MH_TYPE_BACK:
63 len = 1;
64 break;
65 case IP6_MH_TYPE_HOT:
66 case IP6_MH_TYPE_COT:
67 case IP6_MH_TYPE_BERROR:
68 len = 2;
69 break;
70 }
71 return len;
72 }
73
mip6_mh_filter(struct sock * sk,struct sk_buff * skb)74 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
75 {
76 struct ip6_mh _hdr;
77 const struct ip6_mh *mh;
78
79 mh = skb_header_pointer(skb, skb_transport_offset(skb),
80 sizeof(_hdr), &_hdr);
81 if (!mh)
82 return -1;
83
84 if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len)
85 return -1;
86
87 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
88 net_dbg_ratelimited("mip6: MH message too short: %d vs >=%d\n",
89 mh->ip6mh_hdrlen,
90 mip6_mh_len(mh->ip6mh_type));
91 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) +
92 skb_network_header_len(skb));
93 return -1;
94 }
95
96 if (mh->ip6mh_proto != IPPROTO_NONE) {
97 net_dbg_ratelimited("mip6: MH invalid payload proto = %d\n",
98 mh->ip6mh_proto);
99 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) +
100 skb_network_header_len(skb));
101 return -1;
102 }
103
104 return 0;
105 }
106
107 struct mip6_report_rate_limiter {
108 spinlock_t lock;
109 ktime_t stamp;
110 int iif;
111 struct in6_addr src;
112 struct in6_addr dst;
113 };
114
115 static struct mip6_report_rate_limiter mip6_report_rl = {
116 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
117 };
118
mip6_destopt_input(struct xfrm_state * x,struct sk_buff * skb)119 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
120 {
121 const struct ipv6hdr *iph = ipv6_hdr(skb);
122 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
123 int err = destopt->nexthdr;
124
125 spin_lock(&x->lock);
126 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
127 !ipv6_addr_any((struct in6_addr *)x->coaddr))
128 err = -ENOENT;
129 spin_unlock(&x->lock);
130
131 return err;
132 }
133
134 /* Destination Option Header is inserted.
135 * IP Header's src address is replaced with Home Address Option in
136 * Destination Option Header.
137 */
mip6_destopt_output(struct xfrm_state * x,struct sk_buff * skb)138 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
139 {
140 struct ipv6hdr *iph;
141 struct ipv6_destopt_hdr *dstopt;
142 struct ipv6_destopt_hao *hao;
143 u8 nexthdr;
144 int len;
145
146 skb_push(skb, -skb_network_offset(skb));
147 iph = ipv6_hdr(skb);
148
149 nexthdr = *skb_mac_header(skb);
150 *skb_mac_header(skb) = IPPROTO_DSTOPTS;
151
152 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
153 dstopt->nexthdr = nexthdr;
154
155 hao = mip6_padn((char *)(dstopt + 1),
156 calc_padlen(sizeof(*dstopt), 6));
157
158 hao->type = IPV6_TLV_HAO;
159 BUILD_BUG_ON(sizeof(*hao) != 18);
160 hao->length = sizeof(*hao) - 2;
161
162 len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
163
164 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
165 spin_lock_bh(&x->lock);
166 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
167 spin_unlock_bh(&x->lock);
168
169 WARN_ON(len != x->props.header_len);
170 dstopt->hdrlen = (x->props.header_len >> 3) - 1;
171
172 return 0;
173 }
174
mip6_report_rl_allow(ktime_t stamp,const struct in6_addr * dst,const struct in6_addr * src,int iif)175 static inline int mip6_report_rl_allow(ktime_t stamp,
176 const struct in6_addr *dst,
177 const struct in6_addr *src, int iif)
178 {
179 int allow = 0;
180
181 spin_lock_bh(&mip6_report_rl.lock);
182 if (mip6_report_rl.stamp != stamp ||
183 mip6_report_rl.iif != iif ||
184 !ipv6_addr_equal(&mip6_report_rl.src, src) ||
185 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
186 mip6_report_rl.stamp = stamp;
187 mip6_report_rl.iif = iif;
188 mip6_report_rl.src = *src;
189 mip6_report_rl.dst = *dst;
190 allow = 1;
191 }
192 spin_unlock_bh(&mip6_report_rl.lock);
193 return allow;
194 }
195
mip6_destopt_reject(struct xfrm_state * x,struct sk_buff * skb,const struct flowi * fl)196 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
197 const struct flowi *fl)
198 {
199 struct net *net = xs_net(x);
200 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
201 const struct flowi6 *fl6 = &fl->u.ip6;
202 struct ipv6_destopt_hao *hao = NULL;
203 struct xfrm_selector sel;
204 int offset;
205 ktime_t stamp;
206 int err = 0;
207
208 if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
209 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
210 goto out;
211
212 if (likely(opt->dsthao)) {
213 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
214 if (likely(offset >= 0))
215 hao = (struct ipv6_destopt_hao *)
216 (skb_network_header(skb) + offset);
217 }
218
219 stamp = skb_get_ktime(skb);
220
221 if (!mip6_report_rl_allow(stamp, &ipv6_hdr(skb)->daddr,
222 hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
223 opt->iif))
224 goto out;
225
226 memset(&sel, 0, sizeof(sel));
227 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
228 sizeof(sel.daddr));
229 sel.prefixlen_d = 128;
230 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
231 sizeof(sel.saddr));
232 sel.prefixlen_s = 128;
233 sel.family = AF_INET6;
234 sel.proto = fl6->flowi6_proto;
235 sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
236 if (sel.dport)
237 sel.dport_mask = htons(~0);
238 sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
239 if (sel.sport)
240 sel.sport_mask = htons(~0);
241 sel.ifindex = fl6->flowi6_oif;
242
243 err = km_report(net, IPPROTO_DSTOPTS, &sel,
244 (hao ? (xfrm_address_t *)&hao->addr : NULL));
245
246 out:
247 return err;
248 }
249
mip6_destopt_offset(struct xfrm_state * x,struct sk_buff * skb,u8 ** nexthdr)250 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
251 u8 **nexthdr)
252 {
253 u16 offset = sizeof(struct ipv6hdr);
254 struct ipv6_opt_hdr *exthdr =
255 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
256 const unsigned char *nh = skb_network_header(skb);
257 unsigned int packet_len = skb_tail_pointer(skb) -
258 skb_network_header(skb);
259 int found_rhdr = 0;
260
261 *nexthdr = &ipv6_hdr(skb)->nexthdr;
262
263 while (offset + 1 <= packet_len) {
264
265 switch (**nexthdr) {
266 case NEXTHDR_HOP:
267 break;
268 case NEXTHDR_ROUTING:
269 found_rhdr = 1;
270 break;
271 case NEXTHDR_DEST:
272 /*
273 * HAO MUST NOT appear more than once.
274 * XXX: It is better to try to find by the end of
275 * XXX: packet if HAO exists.
276 */
277 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
278 net_dbg_ratelimited("mip6: hao exists already, override\n");
279 return offset;
280 }
281
282 if (found_rhdr)
283 return offset;
284
285 break;
286 default:
287 return offset;
288 }
289
290 offset += ipv6_optlen(exthdr);
291 *nexthdr = &exthdr->nexthdr;
292 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
293 }
294
295 return offset;
296 }
297
mip6_destopt_init_state(struct xfrm_state * x)298 static int mip6_destopt_init_state(struct xfrm_state *x)
299 {
300 if (x->id.spi) {
301 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
302 return -EINVAL;
303 }
304 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
305 pr_info("%s: state's mode is not %u: %u\n",
306 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
307 return -EINVAL;
308 }
309
310 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
311 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
312 sizeof(struct ipv6_destopt_hao);
313 WARN_ON(x->props.header_len != 24);
314
315 return 0;
316 }
317
318 /*
319 * Do nothing about destroying since it has no specific operation for
320 * destination options header unlike IPsec protocols.
321 */
mip6_destopt_destroy(struct xfrm_state * x)322 static void mip6_destopt_destroy(struct xfrm_state *x)
323 {
324 }
325
326 static const struct xfrm_type mip6_destopt_type = {
327 .description = "MIP6DESTOPT",
328 .owner = THIS_MODULE,
329 .proto = IPPROTO_DSTOPTS,
330 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
331 .init_state = mip6_destopt_init_state,
332 .destructor = mip6_destopt_destroy,
333 .input = mip6_destopt_input,
334 .output = mip6_destopt_output,
335 .reject = mip6_destopt_reject,
336 .hdr_offset = mip6_destopt_offset,
337 };
338
mip6_rthdr_input(struct xfrm_state * x,struct sk_buff * skb)339 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
340 {
341 const struct ipv6hdr *iph = ipv6_hdr(skb);
342 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
343 int err = rt2->rt_hdr.nexthdr;
344
345 spin_lock(&x->lock);
346 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
347 !ipv6_addr_any((struct in6_addr *)x->coaddr))
348 err = -ENOENT;
349 spin_unlock(&x->lock);
350
351 return err;
352 }
353
354 /* Routing Header type 2 is inserted.
355 * IP Header's dst address is replaced with Routing Header's Home Address.
356 */
mip6_rthdr_output(struct xfrm_state * x,struct sk_buff * skb)357 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
358 {
359 struct ipv6hdr *iph;
360 struct rt2_hdr *rt2;
361 u8 nexthdr;
362
363 skb_push(skb, -skb_network_offset(skb));
364 iph = ipv6_hdr(skb);
365
366 nexthdr = *skb_mac_header(skb);
367 *skb_mac_header(skb) = IPPROTO_ROUTING;
368
369 rt2 = (struct rt2_hdr *)skb_transport_header(skb);
370 rt2->rt_hdr.nexthdr = nexthdr;
371 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
372 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
373 rt2->rt_hdr.segments_left = 1;
374 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
375
376 WARN_ON(rt2->rt_hdr.hdrlen != 2);
377
378 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
379 spin_lock_bh(&x->lock);
380 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
381 spin_unlock_bh(&x->lock);
382
383 return 0;
384 }
385
mip6_rthdr_offset(struct xfrm_state * x,struct sk_buff * skb,u8 ** nexthdr)386 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
387 u8 **nexthdr)
388 {
389 u16 offset = sizeof(struct ipv6hdr);
390 struct ipv6_opt_hdr *exthdr =
391 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
392 const unsigned char *nh = skb_network_header(skb);
393 unsigned int packet_len = skb_tail_pointer(skb) -
394 skb_network_header(skb);
395 int found_rhdr = 0;
396
397 *nexthdr = &ipv6_hdr(skb)->nexthdr;
398
399 while (offset + 1 <= packet_len) {
400
401 switch (**nexthdr) {
402 case NEXTHDR_HOP:
403 break;
404 case NEXTHDR_ROUTING:
405 if (offset + 3 <= packet_len) {
406 struct ipv6_rt_hdr *rt;
407 rt = (struct ipv6_rt_hdr *)(nh + offset);
408 if (rt->type != 0)
409 return offset;
410 }
411 found_rhdr = 1;
412 break;
413 case NEXTHDR_DEST:
414 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
415 return offset;
416
417 if (found_rhdr)
418 return offset;
419
420 break;
421 default:
422 return offset;
423 }
424
425 offset += ipv6_optlen(exthdr);
426 *nexthdr = &exthdr->nexthdr;
427 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
428 }
429
430 return offset;
431 }
432
mip6_rthdr_init_state(struct xfrm_state * x)433 static int mip6_rthdr_init_state(struct xfrm_state *x)
434 {
435 if (x->id.spi) {
436 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
437 return -EINVAL;
438 }
439 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
440 pr_info("%s: state's mode is not %u: %u\n",
441 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
442 return -EINVAL;
443 }
444
445 x->props.header_len = sizeof(struct rt2_hdr);
446
447 return 0;
448 }
449
450 /*
451 * Do nothing about destroying since it has no specific operation for routing
452 * header type 2 unlike IPsec protocols.
453 */
mip6_rthdr_destroy(struct xfrm_state * x)454 static void mip6_rthdr_destroy(struct xfrm_state *x)
455 {
456 }
457
458 static const struct xfrm_type mip6_rthdr_type = {
459 .description = "MIP6RT",
460 .owner = THIS_MODULE,
461 .proto = IPPROTO_ROUTING,
462 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
463 .init_state = mip6_rthdr_init_state,
464 .destructor = mip6_rthdr_destroy,
465 .input = mip6_rthdr_input,
466 .output = mip6_rthdr_output,
467 .hdr_offset = mip6_rthdr_offset,
468 };
469
mip6_init(void)470 static int __init mip6_init(void)
471 {
472 pr_info("Mobile IPv6\n");
473
474 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
475 pr_info("%s: can't add xfrm type(destopt)\n", __func__);
476 goto mip6_destopt_xfrm_fail;
477 }
478 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
479 pr_info("%s: can't add xfrm type(rthdr)\n", __func__);
480 goto mip6_rthdr_xfrm_fail;
481 }
482 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
483 pr_info("%s: can't add rawv6 mh filter\n", __func__);
484 goto mip6_rawv6_mh_fail;
485 }
486
487
488 return 0;
489
490 mip6_rawv6_mh_fail:
491 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
492 mip6_rthdr_xfrm_fail:
493 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
494 mip6_destopt_xfrm_fail:
495 return -EAGAIN;
496 }
497
mip6_fini(void)498 static void __exit mip6_fini(void)
499 {
500 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
501 pr_info("%s: can't remove rawv6 mh filter\n", __func__);
502 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
503 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
504 }
505
506 module_init(mip6_init);
507 module_exit(mip6_fini);
508
509 MODULE_LICENSE("GPL");
510 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
511 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
512