inet: Call skb_orphan before tproxy activates
[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 inline unsigned int calc_padlen(unsigned int len, unsigned int n)
38 {
39         return (n - len + 16) & 0x7;
40 }
41
42 static inline void *mip6_padn(__u8 *data, __u8 padlen)
43 {
44         if (!data)
45                 return NULL;
46         if (padlen == 1) {
47                 data[0] = IPV6_TLV_PAD0;
48         } else if (padlen > 1) {
49                 data[0] = IPV6_TLV_PADN;
50                 data[1] = padlen - 2;
51                 if (padlen > 2)
52                         memset(data+2, 0, data[1]);
53         }
54         return data + padlen;
55 }
56
57 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
58 {
59         icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev);
60 }
61
62 static int mip6_mh_len(int type)
63 {
64         int len = 0;
65
66         switch (type) {
67         case IP6_MH_TYPE_BRR:
68                 len = 0;
69                 break;
70         case IP6_MH_TYPE_HOTI:
71         case IP6_MH_TYPE_COTI:
72         case IP6_MH_TYPE_BU:
73         case IP6_MH_TYPE_BACK:
74                 len = 1;
75                 break;
76         case IP6_MH_TYPE_HOT:
77         case IP6_MH_TYPE_COT:
78         case IP6_MH_TYPE_BERROR:
79                 len = 2;
80                 break;
81         }
82         return len;
83 }
84
85 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
86 {
87         struct ip6_mh *mh;
88
89         if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) ||
90             !pskb_may_pull(skb, (skb_transport_offset(skb) +
91                                  ((skb_transport_header(skb)[1] + 1) << 3))))
92                 return -1;
93
94         mh = (struct ip6_mh *)skb_transport_header(skb);
95
96         if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
97                 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
98                                mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
99                 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) -
100                                          skb_network_header(skb)));
101                 return -1;
102         }
103
104         if (mh->ip6mh_proto != IPPROTO_NONE) {
105                 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
106                                mh->ip6mh_proto);
107                 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) -
108                                          skb_network_header(skb)));
109                 return -1;
110         }
111
112         return 0;
113 }
114
115 struct mip6_report_rate_limiter {
116         spinlock_t lock;
117         struct timeval stamp;
118         int iif;
119         struct in6_addr src;
120         struct in6_addr dst;
121 };
122
123 static struct mip6_report_rate_limiter mip6_report_rl = {
124         .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
125 };
126
127 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
128 {
129         struct ipv6hdr *iph = ipv6_hdr(skb);
130         struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
131         int err = destopt->nexthdr;
132
133         spin_lock(&x->lock);
134         if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
135             !ipv6_addr_any((struct in6_addr *)x->coaddr))
136                 err = -ENOENT;
137         spin_unlock(&x->lock);
138
139         return err;
140 }
141
142 /* Destination Option Header is inserted.
143  * IP Header's src address is replaced with Home Address Option in
144  * Destination Option Header.
145  */
146 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
147 {
148         struct ipv6hdr *iph;
149         struct ipv6_destopt_hdr *dstopt;
150         struct ipv6_destopt_hao *hao;
151         u8 nexthdr;
152         int len;
153
154         skb_push(skb, -skb_network_offset(skb));
155         iph = ipv6_hdr(skb);
156
157         nexthdr = *skb_mac_header(skb);
158         *skb_mac_header(skb) = IPPROTO_DSTOPTS;
159
160         dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
161         dstopt->nexthdr = nexthdr;
162
163         hao = mip6_padn((char *)(dstopt + 1),
164                         calc_padlen(sizeof(*dstopt), 6));
165
166         hao->type = IPV6_TLV_HAO;
167         BUILD_BUG_ON(sizeof(*hao) != 18);
168         hao->length = sizeof(*hao) - 2;
169
170         len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
171
172         memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
173         spin_lock_bh(&x->lock);
174         memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
175         spin_unlock_bh(&x->lock);
176
177         WARN_ON(len != x->props.header_len);
178         dstopt->hdrlen = (x->props.header_len >> 3) - 1;
179
180         return 0;
181 }
182
183 static inline int mip6_report_rl_allow(struct timeval *stamp,
184                                        struct in6_addr *dst,
185                                        struct in6_addr *src, int iif)
186 {
187         int allow = 0;
188
189         spin_lock_bh(&mip6_report_rl.lock);
190         if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
191             mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
192             mip6_report_rl.iif != iif ||
193             !ipv6_addr_equal(&mip6_report_rl.src, src) ||
194             !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
195                 mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
196                 mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
197                 mip6_report_rl.iif = iif;
198                 ipv6_addr_copy(&mip6_report_rl.src, src);
199                 ipv6_addr_copy(&mip6_report_rl.dst, dst);
200                 allow = 1;
201         }
202         spin_unlock_bh(&mip6_report_rl.lock);
203         return allow;
204 }
205
206 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl)
207 {
208         struct net *net = xs_net(x);
209         struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
210         struct ipv6_destopt_hao *hao = NULL;
211         struct xfrm_selector sel;
212         int offset;
213         struct timeval stamp;
214         int err = 0;
215
216         if (unlikely(fl->proto == IPPROTO_MH &&
217                      fl->fl_mh_type <= IP6_MH_TYPE_MAX))
218                 goto out;
219
220         if (likely(opt->dsthao)) {
221                 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
222                 if (likely(offset >= 0))
223                         hao = (struct ipv6_destopt_hao *)
224                                         (skb_network_header(skb) + offset);
225         }
226
227         skb_get_timestamp(skb, &stamp);
228
229         if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
230                                   hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
231                                   opt->iif))
232                 goto out;
233
234         memset(&sel, 0, sizeof(sel));
235         memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
236                sizeof(sel.daddr));
237         sel.prefixlen_d = 128;
238         memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
239                sizeof(sel.saddr));
240         sel.prefixlen_s = 128;
241         sel.family = AF_INET6;
242         sel.proto = fl->proto;
243         sel.dport = xfrm_flowi_dport(fl);
244         if (sel.dport)
245                 sel.dport_mask = htons(~0);
246         sel.sport = xfrm_flowi_sport(fl);
247         if (sel.sport)
248                 sel.sport_mask = htons(~0);
249         sel.ifindex = fl->oif;
250
251         err = km_report(net, IPPROTO_DSTOPTS, &sel,
252                         (hao ? (xfrm_address_t *)&hao->addr : NULL));
253
254  out:
255         return err;
256 }
257
258 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
259                                u8 **nexthdr)
260 {
261         u16 offset = sizeof(struct ipv6hdr);
262         struct ipv6_opt_hdr *exthdr =
263                                    (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
264         const unsigned char *nh = skb_network_header(skb);
265         unsigned int packet_len = skb->tail - skb->network_header;
266         int found_rhdr = 0;
267
268         *nexthdr = &ipv6_hdr(skb)->nexthdr;
269
270         while (offset + 1 <= packet_len) {
271
272                 switch (**nexthdr) {
273                 case NEXTHDR_HOP:
274                         break;
275                 case NEXTHDR_ROUTING:
276                         found_rhdr = 1;
277                         break;
278                 case NEXTHDR_DEST:
279                         /*
280                          * HAO MUST NOT appear more than once.
281                          * XXX: It is better to try to find by the end of
282                          * XXX: packet if HAO exists.
283                          */
284                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
285                                 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
286                                 return offset;
287                         }
288
289                         if (found_rhdr)
290                                 return offset;
291
292                         break;
293                 default:
294                         return offset;
295                 }
296
297                 offset += ipv6_optlen(exthdr);
298                 *nexthdr = &exthdr->nexthdr;
299                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
300         }
301
302         return offset;
303 }
304
305 static int mip6_destopt_init_state(struct xfrm_state *x)
306 {
307         if (x->id.spi) {
308                 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
309                        x->id.spi);
310                 return -EINVAL;
311         }
312         if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
313                 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
314                        __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
315                 return -EINVAL;
316         }
317
318         x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
319                 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
320                 sizeof(struct ipv6_destopt_hao);
321         WARN_ON(x->props.header_len != 24);
322
323         return 0;
324 }
325
326 /*
327  * Do nothing about destroying since it has no specific operation for
328  * destination options header unlike IPsec protocols.
329  */
330 static void mip6_destopt_destroy(struct xfrm_state *x)
331 {
332 }
333
334 static const struct xfrm_type mip6_destopt_type =
335 {
336         .description    = "MIP6DESTOPT",
337         .owner          = THIS_MODULE,
338         .proto          = IPPROTO_DSTOPTS,
339         .flags          = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
340         .init_state     = mip6_destopt_init_state,
341         .destructor     = mip6_destopt_destroy,
342         .input          = mip6_destopt_input,
343         .output         = mip6_destopt_output,
344         .reject         = mip6_destopt_reject,
345         .hdr_offset     = mip6_destopt_offset,
346 };
347
348 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
349 {
350         struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
351         int err = rt2->rt_hdr.nexthdr;
352
353         spin_lock(&x->lock);
354         if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) &&
355             !ipv6_addr_any((struct in6_addr *)x->coaddr))
356                 err = -ENOENT;
357         spin_unlock(&x->lock);
358
359         return err;
360 }
361
362 /* Routing Header type 2 is inserted.
363  * IP Header's dst address is replaced with Routing Header's Home Address.
364  */
365 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
366 {
367         struct ipv6hdr *iph;
368         struct rt2_hdr *rt2;
369         u8 nexthdr;
370
371         skb_push(skb, -skb_network_offset(skb));
372         iph = ipv6_hdr(skb);
373
374         nexthdr = *skb_mac_header(skb);
375         *skb_mac_header(skb) = IPPROTO_ROUTING;
376
377         rt2 = (struct rt2_hdr *)skb_transport_header(skb);
378         rt2->rt_hdr.nexthdr = nexthdr;
379         rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
380         rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
381         rt2->rt_hdr.segments_left = 1;
382         memset(&rt2->reserved, 0, sizeof(rt2->reserved));
383
384         WARN_ON(rt2->rt_hdr.hdrlen != 2);
385
386         memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
387         spin_lock_bh(&x->lock);
388         memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
389         spin_unlock_bh(&x->lock);
390
391         return 0;
392 }
393
394 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
395                              u8 **nexthdr)
396 {
397         u16 offset = sizeof(struct ipv6hdr);
398         struct ipv6_opt_hdr *exthdr =
399                                    (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
400         const unsigned char *nh = skb_network_header(skb);
401         unsigned int packet_len = skb->tail - skb->network_header;
402         int found_rhdr = 0;
403
404         *nexthdr = &ipv6_hdr(skb)->nexthdr;
405
406         while (offset + 1 <= packet_len) {
407
408                 switch (**nexthdr) {
409                 case NEXTHDR_HOP:
410                         break;
411                 case NEXTHDR_ROUTING:
412                         if (offset + 3 <= packet_len) {
413                                 struct ipv6_rt_hdr *rt;
414                                 rt = (struct ipv6_rt_hdr *)(nh + offset);
415                                 if (rt->type != 0)
416                                         return offset;
417                         }
418                         found_rhdr = 1;
419                         break;
420                 case NEXTHDR_DEST:
421                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
422                                 return offset;
423
424                         if (found_rhdr)
425                                 return offset;
426
427                         break;
428                 default:
429                         return offset;
430                 }
431
432                 offset += ipv6_optlen(exthdr);
433                 *nexthdr = &exthdr->nexthdr;
434                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
435         }
436
437         return offset;
438 }
439
440 static int mip6_rthdr_init_state(struct xfrm_state *x)
441 {
442         if (x->id.spi) {
443                 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
444                        x->id.spi);
445                 return -EINVAL;
446         }
447         if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
448                 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
449                        __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
450                 return -EINVAL;
451         }
452
453         x->props.header_len = sizeof(struct rt2_hdr);
454
455         return 0;
456 }
457
458 /*
459  * Do nothing about destroying since it has no specific operation for routing
460  * header type 2 unlike IPsec protocols.
461  */
462 static void mip6_rthdr_destroy(struct xfrm_state *x)
463 {
464 }
465
466 static const struct xfrm_type mip6_rthdr_type =
467 {
468         .description    = "MIP6RT",
469         .owner          = THIS_MODULE,
470         .proto          = IPPROTO_ROUTING,
471         .flags          = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
472         .init_state     = mip6_rthdr_init_state,
473         .destructor     = mip6_rthdr_destroy,
474         .input          = mip6_rthdr_input,
475         .output         = mip6_rthdr_output,
476         .hdr_offset     = mip6_rthdr_offset,
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", __func__);
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", __func__);
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", __func__);
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", __func__);
511         if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
512                 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__);
513         if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
514                 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__);
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);