99d116caecda4a503be815ec921afc2e3e5a976f
[linux-3.10.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/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 }