7fd841d410190382fe5ea1c4b31df9ebada0f07f
[linux-2.6.git] / net / ipv6 / mip6.c
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 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 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
91 {
92         struct ip6_mh *mh;
93
94         if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) ||
95             !pskb_may_pull(skb, (skb_transport_offset(skb) +
96                                  ((skb_transport_header(skb)[1] + 1) << 3))))
97                 return -1;
98
99         mh = (struct ip6_mh *)skb_transport_header(skb);
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) -
105                                          skb_network_header(skb)));
106                 return -1;
107         }
108
109         if (mh->ip6mh_proto != IPPROTO_NONE) {
110                 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
111                                mh->ip6mh_proto);
112                 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) -
113                                          skb_network_header(skb)));
114                 return -1;
115         }
116
117         return 0;
118 }
119
120 struct mip6_report_rate_limiter {
121         spinlock_t lock;
122         struct timeval stamp;
123         int iif;
124         struct in6_addr src;
125         struct in6_addr dst;
126 };
127
128 static struct mip6_report_rate_limiter mip6_report_rl = {
129         .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
130 };
131
132 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
133 {
134         struct ipv6hdr *iph = ipv6_hdr(skb);
135         struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
136
137         if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
138             !ipv6_addr_any((struct in6_addr *)x->coaddr))
139                 return -ENOENT;
140
141         return destopt->nexthdr;
142 }
143
144 /* Destination Option Header is inserted.
145  * IP Header's src address is replaced with Home Address Option in
146  * Destination Option Header.
147  */
148 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
149 {
150         struct ipv6hdr *iph;
151         struct ipv6_destopt_hdr *dstopt;
152         struct ipv6_destopt_hao *hao;
153         u8 nexthdr;
154         int len;
155
156         skb_push(skb, -skb_network_offset(skb));
157         iph = ipv6_hdr(skb);
158
159         nexthdr = *skb_mac_header(skb);
160         *skb_mac_header(skb) = IPPROTO_DSTOPTS;
161
162         dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
163         dstopt->nexthdr = nexthdr;
164
165         hao = mip6_padn((char *)(dstopt + 1),
166                         calc_padlen(sizeof(*dstopt), 6));
167
168         hao->type = IPV6_TLV_HAO;
169         hao->length = sizeof(*hao) - 2;
170         BUG_TRAP(hao->length == 16);
171
172         len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
173
174         memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
175         spin_lock_bh(&x->lock);
176         memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
177         spin_unlock_bh(&x->lock);
178
179         BUG_TRAP(len == x->props.header_len);
180         dstopt->hdrlen = (x->props.header_len >> 3) - 1;
181
182         return 0;
183 }
184
185 static inline int mip6_report_rl_allow(struct timeval *stamp,
186                                        struct in6_addr *dst,
187                                        struct in6_addr *src, int iif)
188 {
189         int allow = 0;
190
191         spin_lock_bh(&mip6_report_rl.lock);
192         if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
193             mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
194             mip6_report_rl.iif != iif ||
195             !ipv6_addr_equal(&mip6_report_rl.src, src) ||
196             !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
197                 mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
198                 mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
199                 mip6_report_rl.iif = iif;
200                 ipv6_addr_copy(&mip6_report_rl.src, src);
201                 ipv6_addr_copy(&mip6_report_rl.dst, dst);
202                 allow = 1;
203         }
204         spin_unlock_bh(&mip6_report_rl.lock);
205         return allow;
206 }
207
208 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl)
209 {
210         struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
211         struct ipv6_destopt_hao *hao = NULL;
212         struct xfrm_selector sel;
213         int offset;
214         struct timeval stamp;
215         int err = 0;
216
217         if (unlikely(fl->proto == IPPROTO_MH &&
218                      fl->fl_mh_type <= IP6_MH_TYPE_MAX))
219                 goto out;
220
221         if (likely(opt->dsthao)) {
222                 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
223                 if (likely(offset >= 0))
224                         hao = (struct ipv6_destopt_hao *)
225                                         (skb_network_header(skb) + offset);
226         }
227
228         skb_get_timestamp(skb, &stamp);
229
230         if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
231                                   hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
232                                   opt->iif))
233                 goto out;
234
235         memset(&sel, 0, sizeof(sel));
236         memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
237                sizeof(sel.daddr));
238         sel.prefixlen_d = 128;
239         memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
240                sizeof(sel.saddr));
241         sel.prefixlen_s = 128;
242         sel.family = AF_INET6;
243         sel.proto = fl->proto;
244         sel.dport = xfrm_flowi_dport(fl);
245         if (sel.dport)
246                 sel.dport_mask = htons(~0);
247         sel.sport = xfrm_flowi_sport(fl);
248         if (sel.sport)
249                 sel.sport_mask = htons(~0);
250         sel.ifindex = fl->oif;
251
252         err = km_report(IPPROTO_DSTOPTS, &sel,
253                         (hao ? (xfrm_address_t *)&hao->addr : NULL));
254
255  out:
256         return err;
257 }
258
259 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
260                                u8 **nexthdr)
261 {
262         u16 offset = sizeof(struct ipv6hdr);
263         struct ipv6_opt_hdr *exthdr =
264                                    (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
265         const unsigned char *nh = skb_network_header(skb);
266         unsigned int packet_len = skb->tail - skb->network_header;
267         int found_rhdr = 0;
268
269         *nexthdr = &ipv6_hdr(skb)->nexthdr;
270
271         while (offset + 1 <= packet_len) {
272
273                 switch (**nexthdr) {
274                 case NEXTHDR_HOP:
275                         break;
276                 case NEXTHDR_ROUTING:
277                         found_rhdr = 1;
278                         break;
279                 case NEXTHDR_DEST:
280                         /*
281                          * HAO MUST NOT appear more than once.
282                          * XXX: It is better to try to find by the end of
283                          * XXX: packet if HAO exists.
284                          */
285                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
286                                 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
287                                 return offset;
288                         }
289
290                         if (found_rhdr)
291                                 return offset;
292
293                         break;
294                 default:
295                         return offset;
296                 }
297
298                 offset += ipv6_optlen(exthdr);
299                 *nexthdr = &exthdr->nexthdr;
300                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
301         }
302
303         return offset;
304 }
305
306 static int mip6_destopt_init_state(struct xfrm_state *x)
307 {
308         if (x->id.spi) {
309                 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
310                        x->id.spi);
311                 return -EINVAL;
312         }
313         if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
314                 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
315                        __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
316                 return -EINVAL;
317         }
318
319         x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
320                 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
321                 sizeof(struct ipv6_destopt_hao);
322         BUG_TRAP(x->props.header_len == 24);
323
324         return 0;
325 }
326
327 /*
328  * Do nothing about destroying since it has no specific operation for
329  * destination options header unlike IPsec protocols.
330  */
331 static void mip6_destopt_destroy(struct xfrm_state *x)
332 {
333 }
334
335 static struct xfrm_type mip6_destopt_type =
336 {
337         .description    = "MIP6DESTOPT",
338         .owner          = THIS_MODULE,
339         .proto          = IPPROTO_DSTOPTS,
340         .flags          = XFRM_TYPE_NON_FRAGMENT,
341         .init_state     = mip6_destopt_init_state,
342         .destructor     = mip6_destopt_destroy,
343         .input          = mip6_destopt_input,
344         .output         = mip6_destopt_output,
345         .reject         = mip6_destopt_reject,
346         .hdr_offset     = mip6_destopt_offset,
347         .local_addr     = mip6_xfrm_addr,
348 };
349
350 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
351 {
352         struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
353
354         if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
355             !ipv6_addr_any((struct in6_addr *)x->coaddr))
356                 return -ENOENT;
357
358         return rt2->rt_hdr.nexthdr;
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 struct xfrm_type mip6_rthdr_type =
466 {
467         .description    = "MIP6RT",
468         .owner          = THIS_MODULE,
469         .proto          = IPPROTO_ROUTING,
470         .flags          = XFRM_TYPE_NON_FRAGMENT,
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         .remote_addr    = mip6_xfrm_addr,
477 };
478
479 static int __init mip6_init(void)
480 {
481         printk(KERN_INFO "Mobile IPv6\n");
482
483         if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
484                 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__);
485                 goto mip6_destopt_xfrm_fail;
486         }
487         if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
488                 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__);
489                 goto mip6_rthdr_xfrm_fail;
490         }
491         if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
492                 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __FUNCTION__);
493                 goto mip6_rawv6_mh_fail;
494         }
495
496
497         return 0;
498
499  mip6_rawv6_mh_fail:
500         xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
501  mip6_rthdr_xfrm_fail:
502         xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
503  mip6_destopt_xfrm_fail:
504         return -EAGAIN;
505 }
506
507 static void __exit mip6_fini(void)
508 {
509         if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
510                 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __FUNCTION__);
511         if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
512                 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
513         if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
514                 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__);
515 }
516
517 module_init(mip6_init);
518 module_exit(mip6_fini);
519
520 MODULE_LICENSE("GPL");
521 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
522 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);