sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
[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);
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         const 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                                        const struct in6_addr *dst,
185                                        const 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,
207                                const struct flowi *fl)
208 {
209         struct net *net = xs_net(x);
210         struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
211         const struct flowi6 *fl6 = &fl->u.ip6;
212         struct ipv6_destopt_hao *hao = NULL;
213         struct xfrm_selector sel;
214         int offset;
215         struct timeval stamp;
216         int err = 0;
217
218         if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
219                      fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
220                 goto out;
221
222         if (likely(opt->dsthao)) {
223                 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
224                 if (likely(offset >= 0))
225                         hao = (struct ipv6_destopt_hao *)
226                                         (skb_network_header(skb) + offset);
227         }
228
229         skb_get_timestamp(skb, &stamp);
230
231         if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
232                                   hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
233                                   opt->iif))
234                 goto out;
235
236         memset(&sel, 0, sizeof(sel));
237         memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
238                sizeof(sel.daddr));
239         sel.prefixlen_d = 128;
240         memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
241                sizeof(sel.saddr));
242         sel.prefixlen_s = 128;
243         sel.family = AF_INET6;
244         sel.proto = fl6->flowi6_proto;
245         sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
246         if (sel.dport)
247                 sel.dport_mask = htons(~0);
248         sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
249         if (sel.sport)
250                 sel.sport_mask = htons(~0);
251         sel.ifindex = fl6->flowi6_oif;
252
253         err = km_report(net, IPPROTO_DSTOPTS, &sel,
254                         (hao ? (xfrm_address_t *)&hao->addr : NULL));
255
256  out:
257         return err;
258 }
259
260 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
261                                u8 **nexthdr)
262 {
263         u16 offset = sizeof(struct ipv6hdr);
264         struct ipv6_opt_hdr *exthdr =
265                                    (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
266         const unsigned char *nh = skb_network_header(skb);
267         unsigned int packet_len = skb->tail - skb->network_header;
268         int found_rhdr = 0;
269
270         *nexthdr = &ipv6_hdr(skb)->nexthdr;
271
272         while (offset + 1 <= packet_len) {
273
274                 switch (**nexthdr) {
275                 case NEXTHDR_HOP:
276                         break;
277                 case NEXTHDR_ROUTING:
278                         found_rhdr = 1;
279                         break;
280                 case NEXTHDR_DEST:
281                         /*
282                          * HAO MUST NOT appear more than once.
283                          * XXX: It is better to try to find by the end of
284                          * XXX: packet if HAO exists.
285                          */
286                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
287                                 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
288                                 return offset;
289                         }
290
291                         if (found_rhdr)
292                                 return offset;
293
294                         break;
295                 default:
296                         return offset;
297                 }
298
299                 offset += ipv6_optlen(exthdr);
300                 *nexthdr = &exthdr->nexthdr;
301                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
302         }
303
304         return offset;
305 }
306
307 static int mip6_destopt_init_state(struct xfrm_state *x)
308 {
309         if (x->id.spi) {
310                 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
311                        x->id.spi);
312                 return -EINVAL;
313         }
314         if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
315                 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
316                        __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
317                 return -EINVAL;
318         }
319
320         x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
321                 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
322                 sizeof(struct ipv6_destopt_hao);
323         WARN_ON(x->props.header_len != 24);
324
325         return 0;
326 }
327
328 /*
329  * Do nothing about destroying since it has no specific operation for
330  * destination options header unlike IPsec protocols.
331  */
332 static void mip6_destopt_destroy(struct xfrm_state *x)
333 {
334 }
335
336 static const struct xfrm_type mip6_destopt_type =
337 {
338         .description    = "MIP6DESTOPT",
339         .owner          = THIS_MODULE,
340         .proto          = IPPROTO_DSTOPTS,
341         .flags          = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
342         .init_state     = mip6_destopt_init_state,
343         .destructor     = mip6_destopt_destroy,
344         .input          = mip6_destopt_input,
345         .output         = mip6_destopt_output,
346         .reject         = mip6_destopt_reject,
347         .hdr_offset     = mip6_destopt_offset,
348 };
349
350 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
351 {
352         const struct ipv6hdr *iph = ipv6_hdr(skb);
353         struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
354         int err = rt2->rt_hdr.nexthdr;
355
356         spin_lock(&x->lock);
357         if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
358             !ipv6_addr_any((struct in6_addr *)x->coaddr))
359                 err = -ENOENT;
360         spin_unlock(&x->lock);
361
362         return err;
363 }
364
365 /* Routing Header type 2 is inserted.
366  * IP Header's dst address is replaced with Routing Header's Home Address.
367  */
368 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
369 {
370         struct ipv6hdr *iph;
371         struct rt2_hdr *rt2;
372         u8 nexthdr;
373
374         skb_push(skb, -skb_network_offset(skb));
375         iph = ipv6_hdr(skb);
376
377         nexthdr = *skb_mac_header(skb);
378         *skb_mac_header(skb) = IPPROTO_ROUTING;
379
380         rt2 = (struct rt2_hdr *)skb_transport_header(skb);
381         rt2->rt_hdr.nexthdr = nexthdr;
382         rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
383         rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
384         rt2->rt_hdr.segments_left = 1;
385         memset(&rt2->reserved, 0, sizeof(rt2->reserved));
386
387         WARN_ON(rt2->rt_hdr.hdrlen != 2);
388
389         memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
390         spin_lock_bh(&x->lock);
391         memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
392         spin_unlock_bh(&x->lock);
393
394         return 0;
395 }
396
397 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
398                              u8 **nexthdr)
399 {
400         u16 offset = sizeof(struct ipv6hdr);
401         struct ipv6_opt_hdr *exthdr =
402                                    (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
403         const unsigned char *nh = skb_network_header(skb);
404         unsigned int packet_len = skb->tail - skb->network_header;
405         int found_rhdr = 0;
406
407         *nexthdr = &ipv6_hdr(skb)->nexthdr;
408
409         while (offset + 1 <= packet_len) {
410
411                 switch (**nexthdr) {
412                 case NEXTHDR_HOP:
413                         break;
414                 case NEXTHDR_ROUTING:
415                         if (offset + 3 <= packet_len) {
416                                 struct ipv6_rt_hdr *rt;
417                                 rt = (struct ipv6_rt_hdr *)(nh + offset);
418                                 if (rt->type != 0)
419                                         return offset;
420                         }
421                         found_rhdr = 1;
422                         break;
423                 case NEXTHDR_DEST:
424                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
425                                 return offset;
426
427                         if (found_rhdr)
428                                 return offset;
429
430                         break;
431                 default:
432                         return offset;
433                 }
434
435                 offset += ipv6_optlen(exthdr);
436                 *nexthdr = &exthdr->nexthdr;
437                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
438         }
439
440         return offset;
441 }
442
443 static int mip6_rthdr_init_state(struct xfrm_state *x)
444 {
445         if (x->id.spi) {
446                 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__,
447                        x->id.spi);
448                 return -EINVAL;
449         }
450         if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
451                 printk(KERN_INFO "%s: state's mode is not %u: %u\n",
452                        __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
453                 return -EINVAL;
454         }
455
456         x->props.header_len = sizeof(struct rt2_hdr);
457
458         return 0;
459 }
460
461 /*
462  * Do nothing about destroying since it has no specific operation for routing
463  * header type 2 unlike IPsec protocols.
464  */
465 static void mip6_rthdr_destroy(struct xfrm_state *x)
466 {
467 }
468
469 static const struct xfrm_type mip6_rthdr_type =
470 {
471         .description    = "MIP6RT",
472         .owner          = THIS_MODULE,
473         .proto          = IPPROTO_ROUTING,
474         .flags          = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
475         .init_state     = mip6_rthdr_init_state,
476         .destructor     = mip6_rthdr_destroy,
477         .input          = mip6_rthdr_input,
478         .output         = mip6_rthdr_output,
479         .hdr_offset     = mip6_rthdr_offset,
480 };
481
482 static int __init mip6_init(void)
483 {
484         printk(KERN_INFO "Mobile IPv6\n");
485
486         if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
487                 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __func__);
488                 goto mip6_destopt_xfrm_fail;
489         }
490         if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
491                 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __func__);
492                 goto mip6_rthdr_xfrm_fail;
493         }
494         if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
495                 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __func__);
496                 goto mip6_rawv6_mh_fail;
497         }
498
499
500         return 0;
501
502  mip6_rawv6_mh_fail:
503         xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
504  mip6_rthdr_xfrm_fail:
505         xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
506  mip6_destopt_xfrm_fail:
507         return -EAGAIN;
508 }
509
510 static void __exit mip6_fini(void)
511 {
512         if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
513                 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__);
514         if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
515                 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__);
516         if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
517                 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__);
518 }
519
520 module_init(mip6_init);
521 module_exit(mip6_fini);
522
523 MODULE_LICENSE("GPL");
524 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
525 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);