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[PATCH] oom-kill: update comments to reflect current code
[pv_ops_mirror.git] / net / ipv6 / mip6.c
blob99d116caecda4a503be815ec921afc2e3e5a976f
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/config.h>
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/xfrm.h>
35 #include <net/mip6.h>
36
37 static xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr)
38 {
39 return x->coaddr;
40 }
41
42 static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
43 {
44 return (n - len + 16) & 0x7;
45 }
46
47 static inline void *mip6_padn(__u8 *data, __u8 padlen)
48 {
49 if (!data)
50 return NULL;
51 if (padlen == 1) {
52 data[0] = MIP6_OPT_PAD_1;
53 } else if (padlen > 1) {
54 data[0] = MIP6_OPT_PAD_N;
55 data[1] = padlen - 2;
56 if (padlen > 2)
57 memset(data+2, 0, data[1]);
58 }
59 return data + padlen;
60 }
61
62 static inline void mip6_param_prob(struct sk_buff *skb, int code, int pos)
63 {
64 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
65 }
66
67 static int mip6_mh_len(int type)
68 {
69 int len = 0;
70
71 switch (type) {
72 case IP6_MH_TYPE_BRR:
73 len = 0;
74 break;
75 case IP6_MH_TYPE_HOTI:
76 case IP6_MH_TYPE_COTI:
77 case IP6_MH_TYPE_BU:
78 case IP6_MH_TYPE_BACK:
79 len = 1;
80 break;
81 case IP6_MH_TYPE_HOT:
82 case IP6_MH_TYPE_COT:
83 case IP6_MH_TYPE_BERROR:
84 len = 2;
85 break;
86 }
87 return len;
88 }
89
90 int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
91 {
92 struct ip6_mh *mh;
93 int mhlen;
94
95 if (!pskb_may_pull(skb, (skb->h.raw - skb->data) + 8) ||
96 !pskb_may_pull(skb, (skb->h.raw - skb->data) + ((skb->h.raw[1] + 1) << 3)))
97 return -1;
98
99 mh = (struct ip6_mh *)skb->h.raw;
100
101 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
102 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
103 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
104 mip6_param_prob(skb, 0, (&mh->ip6mh_hdrlen) - skb->nh.raw);
105 return -1;
106 }
107 mhlen = (mh->ip6mh_hdrlen + 1) << 3;
108
109 if (skb->ip_summed == CHECKSUM_COMPLETE) {
110 skb->ip_summed = CHECKSUM_UNNECESSARY;
111 if (csum_ipv6_magic(&skb->nh.ipv6h->saddr,
112 &skb->nh.ipv6h->daddr,
113 mhlen, IPPROTO_MH,
114 skb->csum)) {
115 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH hw checksum failed\n");
116 skb->ip_summed = CHECKSUM_NONE;
117 }
118 }
119 if (skb->ip_summed == CHECKSUM_NONE) {
120 if (csum_ipv6_magic(&skb->nh.ipv6h->saddr,
121 &skb->nh.ipv6h->daddr,
122 mhlen, IPPROTO_MH,
123 skb_checksum(skb, 0, mhlen, 0))) {
124 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH checksum failed "
125 "[" NIP6_FMT " > " NIP6_FMT "]\n",
126 NIP6(skb->nh.ipv6h->saddr),
127 NIP6(skb->nh.ipv6h->daddr));
128 return -1;
129 }
130 skb->ip_summed = CHECKSUM_UNNECESSARY;
131 }
132
133 if (mh->ip6mh_proto != IPPROTO_NONE) {
134 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
135 mh->ip6mh_proto);
136 mip6_param_prob(skb, 0, (&mh->ip6mh_proto) - skb->nh.raw);
137 return -1;
138 }
139
140 return 0;
141 }
142
143 struct mip6_report_rate_limiter {
144 spinlock_t lock;
145 struct timeval stamp;
146 int iif;
147 struct in6_addr src;
148 struct in6_addr dst;
149 };
150
151 static struct mip6_report_rate_limiter mip6_report_rl = {
152 .lock = SPIN_LOCK_UNLOCKED
153 };
154
155 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
156 {
157 struct ipv6hdr *iph = skb->nh.ipv6h;
158 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
159
160 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
161 !ipv6_addr_any((struct in6_addr *)x->coaddr))
162 return -ENOENT;
163
164 return destopt->nexthdr;
165 }
166
167 /* Destination Option Header is inserted.
168 * IP Header's src address is replaced with Home Address Option in
169 * Destination Option Header.
170 */
171 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
172 {
173 struct ipv6hdr *iph;
174 struct ipv6_destopt_hdr *dstopt;
175 struct ipv6_destopt_hao *hao;
176 u8 nexthdr;
177 int len;
178
179 iph = (struct ipv6hdr *)skb->data;
180 iph->payload_len = htons(skb->len - sizeof(*iph));
181
182 nexthdr = *skb->nh.raw;
183 *skb->nh.raw = IPPROTO_DSTOPTS;
184
185 dstopt = (struct ipv6_destopt_hdr *)skb->h.raw;
186 dstopt->nexthdr = nexthdr;
187
188 hao = mip6_padn((char *)(dstopt + 1),
189 calc_padlen(sizeof(*dstopt), 6));
190
191 hao->type = IPV6_TLV_HAO;
192 hao->length = sizeof(*hao) - 2;
193 BUG_TRAP(hao->length == 16);
194
195 len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
196
197 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
198 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
199
200 BUG_TRAP(len == x->props.header_len);
201 dstopt->hdrlen = (x->props.header_len >> 3) - 1;
202
203 return 0;
204 }
205
206 static inline int mip6_report_rl_allow(struct timeval *stamp,
207 struct in6_addr *dst,
208 struct in6_addr *src, int iif)
209 {
210 int allow = 0;
211
212 spin_lock_bh(&mip6_report_rl.lock);
213 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
214 mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
215 mip6_report_rl.iif != iif ||
216 !ipv6_addr_equal(&mip6_report_rl.src, src) ||
217 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
218 mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
219 mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
220 mip6_report_rl.iif = iif;
221 ipv6_addr_copy(&mip6_report_rl.src, src);
222 ipv6_addr_copy(&mip6_report_rl.dst, dst);
223 allow = 1;
224 }
225 spin_unlock_bh(&mip6_report_rl.lock);
226 return allow;
227 }
228
229 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl)
230 {
231 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
232 struct ipv6_destopt_hao *hao = NULL;
233 struct xfrm_selector sel;
234 int offset;
235 struct timeval stamp;
236 int err = 0;
237
238 if (unlikely(fl->proto == IPPROTO_MH &&
239 fl->fl_mh_type <= IP6_MH_TYPE_MAX))
240 goto out;
241
242 if (likely(opt->dsthao)) {
243 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
244 if (likely(offset >= 0))
245 hao = (struct ipv6_destopt_hao *)(skb->nh.raw + offset);
246 }
247
248 skb_get_timestamp(skb, &stamp);
249
250 if (!mip6_report_rl_allow(&stamp, &skb->nh.ipv6h->daddr,
251 hao ? &hao->addr : &skb->nh.ipv6h->saddr,
252 opt->iif))
253 goto out;
254
255 memset(&sel, 0, sizeof(sel));
256 memcpy(&sel.daddr, (xfrm_address_t *)&skb->nh.ipv6h->daddr,
257 sizeof(sel.daddr));
258 sel.prefixlen_d = 128;
259 memcpy(&sel.saddr, (xfrm_address_t *)&skb->nh.ipv6h->saddr,
260 sizeof(sel.saddr));
261 sel.prefixlen_s = 128;
262 sel.family = AF_INET6;
263 sel.proto = fl->proto;
264 sel.dport = xfrm_flowi_dport(fl);
265 if (sel.dport)
266 sel.dport_mask = ~((__u16)0);
267 sel.sport = xfrm_flowi_sport(fl);
268 if (sel.sport)
269 sel.sport_mask = ~((__u16)0);
270 sel.ifindex = fl->oif;
271
272 err = km_report(IPPROTO_DSTOPTS, &sel,
273 (hao ? (xfrm_address_t *)&hao->addr : NULL));
274
275 out:
276 return err;
277 }
278
279 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
280 u8 **nexthdr)
281 {
282 u16 offset = sizeof(struct ipv6hdr);
283 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
284 unsigned int packet_len = skb->tail - skb->nh.raw;
285 int found_rhdr = 0;
286
287 *nexthdr = &skb->nh.ipv6h->nexthdr;
288
289 while (offset + 1 <= packet_len) {
290
291 switch (**nexthdr) {
292 case NEXTHDR_HOP:
293 break;
294 case NEXTHDR_ROUTING:
295 found_rhdr = 1;
296 break;
297 case NEXTHDR_DEST:
298 /*
299 * HAO MUST NOT appear more than once.
300 * XXX: It is better to try to find by the end of
301 * XXX: packet if HAO exists.
302 */
303 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
304 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
305 return offset;
306 }
307
308 if (found_rhdr)
309 return offset;
310
311 break;
312 default:
313 return offset;
314 }
315
316 offset += ipv6_optlen(exthdr);
317 *nexthdr = &exthdr->nexthdr;
318 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
319 }
320
321 return offset;
322 }
323
324 static int mip6_destopt_init_state(struct xfrm_state *x)
325 {
326 if (x->id.spi) {
327 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
328 x->id.spi);
329 return -EINVAL;
330 }
331 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
332 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
333 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
334 return -EINVAL;
335 }
336
337 x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
338 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
339 sizeof(struct ipv6_destopt_hao);
340 BUG_TRAP(x->props.header_len == 24);
341
342 return 0;
343 }
344
345 /*
346 * Do nothing about destroying since it has no specific operation for
347 * destination options header unlike IPsec protocols.
348 */
349 static void mip6_destopt_destroy(struct xfrm_state *x)
350 {
351 }
352
353 static struct xfrm_type mip6_destopt_type =
354 {
355 .description = "MIP6DESTOPT",
356 .owner = THIS_MODULE,
357 .proto = IPPROTO_DSTOPTS,
358 .flags = XFRM_TYPE_NON_FRAGMENT,
359 .init_state = mip6_destopt_init_state,
360 .destructor = mip6_destopt_destroy,
361 .input = mip6_destopt_input,
362 .output = mip6_destopt_output,
363 .reject = mip6_destopt_reject,
364 .hdr_offset = mip6_destopt_offset,
365 .local_addr = mip6_xfrm_addr,
366 };
367
368 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
369 {
370 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
371
372 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
373 !ipv6_addr_any((struct in6_addr *)x->coaddr))
374 return -ENOENT;
375
376 return rt2->rt_hdr.nexthdr;
377 }
378
379 /* Routing Header type 2 is inserted.
380 * IP Header's dst address is replaced with Routing Header's Home Address.
381 */
382 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
383 {
384 struct ipv6hdr *iph;
385 struct rt2_hdr *rt2;
386 u8 nexthdr;
387
388 iph = (struct ipv6hdr *)skb->data;
389 iph->payload_len = htons(skb->len - sizeof(*iph));
390
391 nexthdr = *skb->nh.raw;
392 *skb->nh.raw = IPPROTO_ROUTING;
393
394 rt2 = (struct rt2_hdr *)skb->h.raw;
395 rt2->rt_hdr.nexthdr = nexthdr;
396 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
397 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
398 rt2->rt_hdr.segments_left = 1;
399 memset(&rt2->reserved, 0, sizeof(rt2->reserved));
400
401 BUG_TRAP(rt2->rt_hdr.hdrlen == 2);
402
403 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
404 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
405
406 return 0;
407 }
408
409 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
410 u8 **nexthdr)
411 {
412 u16 offset = sizeof(struct ipv6hdr);
413 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
414 unsigned int packet_len = skb->tail - skb->nh.raw;
415 int found_rhdr = 0;
416
417 *nexthdr = &skb->nh.ipv6h->nexthdr;
418
419 while (offset + 1 <= packet_len) {
420
421 switch (**nexthdr) {
422 case NEXTHDR_HOP:
423 break;
424 case NEXTHDR_ROUTING:
425 if (offset + 3 <= packet_len) {
426 struct ipv6_rt_hdr *rt;
427 rt = (struct ipv6_rt_hdr *)(skb->nh.raw + offset);
428 if (rt->type != 0)
429 return offset;
430 }
431 found_rhdr = 1;
432 break;
433 case NEXTHDR_DEST:
434 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
435 return offset;
436
437 if (found_rhdr)
438 return offset;
439
440 break;
441 default:
442 return offset;
443 }
444
445 offset += ipv6_optlen(exthdr);
446 *nexthdr = &exthdr->nexthdr;
447 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
448 }
449
450 return offset;
451 }
452
453 static int mip6_rthdr_init_state(struct xfrm_state *x)
454 {
455 if (x->id.spi) {
456 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
457 x->id.spi);
458 return -EINVAL;
459 }
460 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
461 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
462 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
463 return -EINVAL;
464 }
465
466 x->props.header_len = sizeof(struct rt2_hdr);
467
468 return 0;
469 }
470
471 /*
472 * Do nothing about destroying since it has no specific operation for routing
473 * header type 2 unlike IPsec protocols.
474 */
475 static void mip6_rthdr_destroy(struct xfrm_state *x)
476 {
477 }
478
479 static struct xfrm_type mip6_rthdr_type =
480 {
481 .description = "MIP6RT",
482 .owner = THIS_MODULE,
483 .proto = IPPROTO_ROUTING,
484 .flags = XFRM_TYPE_NON_FRAGMENT,
485 .init_state = mip6_rthdr_init_state,
486 .destructor = mip6_rthdr_destroy,
487 .input = mip6_rthdr_input,
488 .output = mip6_rthdr_output,
489 .hdr_offset = mip6_rthdr_offset,
490 .remote_addr = mip6_xfrm_addr,
491 };
492
493 int __init mip6_init(void)
494 {
495 printk(KERN_INFO "Mobile IPv6\n");
496
497 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
498 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__);
499 goto mip6_destopt_xfrm_fail;
500 }
501 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
502 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__);
503 goto mip6_rthdr_xfrm_fail;
504 }
505 return 0;
506
507 mip6_rthdr_xfrm_fail:
508 xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
509 mip6_destopt_xfrm_fail:
510 return -EAGAIN;
511 }
512
513 void __exit mip6_fini(void)
514 {
515 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
516 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
517 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
518 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__);
519 }
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