[NET]: Fix "ntohl(ntohs" bugs
[linux-2.6.git] / net / ipv6 / ipcomp6.c
1 /*
2  * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
3  *
4  * Copyright (C)2003 USAGI/WIDE Project
5  *
6  * Author       Mitsuru KANDA  <mk@linux-ipv6.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  * 
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  * 
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21  */
22 /* 
23  * [Memo]
24  *
25  * Outbound:
26  *  The compression of IP datagram MUST be done before AH/ESP processing, 
27  *  fragmentation, and the addition of Hop-by-Hop/Routing header. 
28  *
29  * Inbound:
30  *  The decompression of IP datagram MUST be done after the reassembly, 
31  *  AH/ESP processing.
32  */
33 #include <linux/config.h>
34 #include <linux/module.h>
35 #include <net/ip.h>
36 #include <net/xfrm.h>
37 #include <net/ipcomp.h>
38 #include <asm/scatterlist.h>
39 #include <asm/semaphore.h>
40 #include <linux/crypto.h>
41 #include <linux/pfkeyv2.h>
42 #include <linux/random.h>
43 #include <linux/percpu.h>
44 #include <linux/smp.h>
45 #include <linux/list.h>
46 #include <linux/vmalloc.h>
47 #include <linux/rtnetlink.h>
48 #include <net/icmp.h>
49 #include <net/ipv6.h>
50 #include <net/protocol.h>
51 #include <linux/ipv6.h>
52 #include <linux/icmpv6.h>
53 #include <linux/mutex.h>
54
55 struct ipcomp6_tfms {
56         struct list_head list;
57         struct crypto_tfm **tfms;
58         int users;
59 };
60
61 static DEFINE_MUTEX(ipcomp6_resource_mutex);
62 static void **ipcomp6_scratches;
63 static int ipcomp6_scratch_users;
64 static LIST_HEAD(ipcomp6_tfms_list);
65
66 static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
67 {
68         int err = 0;
69         u8 nexthdr = 0;
70         int hdr_len = skb->h.raw - skb->nh.raw;
71         unsigned char *tmp_hdr = NULL;
72         struct ipv6hdr *iph;
73         int plen, dlen;
74         struct ipcomp_data *ipcd = x->data;
75         u8 *start, *scratch;
76         struct crypto_tfm *tfm;
77         int cpu;
78
79         if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
80                 skb_linearize(skb, GFP_ATOMIC) != 0) {
81                 err = -ENOMEM;
82                 goto out;
83         }
84
85         skb->ip_summed = CHECKSUM_NONE;
86
87         /* Remove ipcomp header and decompress original payload */
88         iph = skb->nh.ipv6h;
89         tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
90         if (!tmp_hdr)
91                 goto out;
92         memcpy(tmp_hdr, iph, hdr_len);
93         nexthdr = *(u8 *)skb->data;
94         skb_pull(skb, sizeof(struct ipv6_comp_hdr)); 
95         skb->nh.raw += sizeof(struct ipv6_comp_hdr);
96         memcpy(skb->nh.raw, tmp_hdr, hdr_len);
97         iph = skb->nh.ipv6h;
98         iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
99         skb->h.raw = skb->data;
100
101         /* decompression */
102         plen = skb->len;
103         dlen = IPCOMP_SCRATCH_SIZE;
104         start = skb->data;
105
106         cpu = get_cpu();
107         scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
108         tfm = *per_cpu_ptr(ipcd->tfms, cpu);
109
110         err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
111         if (err) {
112                 err = -EINVAL;
113                 goto out_put_cpu;
114         }
115
116         if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {
117                 err = -EINVAL;
118                 goto out_put_cpu;
119         }
120
121         err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
122         if (err) {
123                 goto out_put_cpu;
124         }
125
126         skb_put(skb, dlen - plen);
127         memcpy(skb->data, scratch, dlen);
128
129         iph = skb->nh.ipv6h;
130         iph->payload_len = htons(skb->len);
131         
132 out_put_cpu:
133         put_cpu();
134 out:
135         kfree(tmp_hdr);
136         if (err)
137                 goto error_out;
138         return nexthdr;
139 error_out:
140         return err;
141 }
142
143 static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
144 {
145         int err;
146         struct ipv6hdr *top_iph;
147         int hdr_len;
148         struct ipv6_comp_hdr *ipch;
149         struct ipcomp_data *ipcd = x->data;
150         int plen, dlen;
151         u8 *start, *scratch;
152         struct crypto_tfm *tfm;
153         int cpu;
154
155         hdr_len = skb->h.raw - skb->data;
156
157         /* check whether datagram len is larger than threshold */
158         if ((skb->len - hdr_len) < ipcd->threshold) {
159                 goto out_ok;
160         }
161
162         if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
163                 skb_linearize(skb, GFP_ATOMIC) != 0) {
164                 goto out_ok;
165         }
166
167         /* compression */
168         plen = skb->len - hdr_len;
169         dlen = IPCOMP_SCRATCH_SIZE;
170         start = skb->h.raw;
171
172         cpu = get_cpu();
173         scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
174         tfm = *per_cpu_ptr(ipcd->tfms, cpu);
175
176         err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
177         if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {
178                 put_cpu();
179                 goto out_ok;
180         }
181         memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
182         put_cpu();
183         pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr));
184
185         /* insert ipcomp header and replace datagram */
186         top_iph = (struct ipv6hdr *)skb->data;
187
188         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
189
190         ipch = (struct ipv6_comp_hdr *)start;
191         ipch->nexthdr = *skb->nh.raw;
192         ipch->flags = 0;
193         ipch->cpi = htons((u16 )ntohl(x->id.spi));
194         *skb->nh.raw = IPPROTO_COMP;
195
196 out_ok:
197         return 0;
198 }
199
200 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
201                                 int type, int code, int offset, __u32 info)
202 {
203         u32 spi;
204         struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
205         struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);
206         struct xfrm_state *x;
207
208         if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
209                 return;
210
211         spi = htonl(ntohs(ipcomph->cpi));
212         x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
213         if (!x)
214                 return;
215
216         printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
217                         spi, NIP6(iph->daddr));
218         xfrm_state_put(x);
219 }
220
221 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
222 {
223         struct xfrm_state *t = NULL;
224
225         t = xfrm_state_alloc();
226         if (!t)
227                 goto out;
228
229         t->id.proto = IPPROTO_IPV6;
230         t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
231         if (!t->id.spi)
232                 goto error;
233
234         memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
235         memcpy(&t->sel, &x->sel, sizeof(t->sel));
236         t->props.family = AF_INET6;
237         t->props.mode = 1;
238         memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
239
240         if (xfrm_init_state(t))
241                 goto error;
242
243         atomic_set(&t->tunnel_users, 1);
244
245 out:
246         return t;
247
248 error:
249         t->km.state = XFRM_STATE_DEAD;
250         xfrm_state_put(t);
251         t = NULL;
252         goto out;
253 }
254
255 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
256 {
257         int err = 0;
258         struct xfrm_state *t = NULL;
259         u32 spi;
260
261         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
262         if (spi)
263                 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
264                                               spi, IPPROTO_IPV6, AF_INET6);
265         if (!t) {
266                 t = ipcomp6_tunnel_create(x);
267                 if (!t) {
268                         err = -EINVAL;
269                         goto out;
270                 }
271                 xfrm_state_insert(t);
272                 xfrm_state_hold(t);
273         }
274         x->tunnel = t;
275         atomic_inc(&t->tunnel_users);
276
277 out:
278         return err;
279 }
280
281 static void ipcomp6_free_scratches(void)
282 {
283         int i;
284         void **scratches;
285
286         if (--ipcomp6_scratch_users)
287                 return;
288
289         scratches = ipcomp6_scratches;
290         if (!scratches)
291                 return;
292
293         for_each_possible_cpu(i) {
294                 void *scratch = *per_cpu_ptr(scratches, i);
295
296                 vfree(scratch);
297         }
298
299         free_percpu(scratches);
300 }
301
302 static void **ipcomp6_alloc_scratches(void)
303 {
304         int i;
305         void **scratches;
306
307         if (ipcomp6_scratch_users++)
308                 return ipcomp6_scratches;
309
310         scratches = alloc_percpu(void *);
311         if (!scratches)
312                 return NULL;
313
314         ipcomp6_scratches = scratches;
315
316         for_each_possible_cpu(i) {
317                 void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
318                 if (!scratch)
319                         return NULL;
320                 *per_cpu_ptr(scratches, i) = scratch;
321         }
322
323         return scratches;
324 }
325
326 static void ipcomp6_free_tfms(struct crypto_tfm **tfms)
327 {
328         struct ipcomp6_tfms *pos;
329         int cpu;
330
331         list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
332                 if (pos->tfms == tfms)
333                         break;
334         }
335
336         BUG_TRAP(pos);
337
338         if (--pos->users)
339                 return;
340
341         list_del(&pos->list);
342         kfree(pos);
343
344         if (!tfms)
345                 return;
346
347         for_each_possible_cpu(cpu) {
348                 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
349                 crypto_free_tfm(tfm);
350         }
351         free_percpu(tfms);
352 }
353
354 static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
355 {
356         struct ipcomp6_tfms *pos;
357         struct crypto_tfm **tfms;
358         int cpu;
359
360         /* This can be any valid CPU ID so we don't need locking. */
361         cpu = raw_smp_processor_id();
362
363         list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
364                 struct crypto_tfm *tfm;
365
366                 tfms = pos->tfms;
367                 tfm = *per_cpu_ptr(tfms, cpu);
368
369                 if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) {
370                         pos->users++;
371                         return tfms;
372                 }
373         }
374
375         pos = kmalloc(sizeof(*pos), GFP_KERNEL);
376         if (!pos)
377                 return NULL;
378
379         pos->users = 1;
380         INIT_LIST_HEAD(&pos->list);
381         list_add(&pos->list, &ipcomp6_tfms_list);
382
383         pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
384         if (!tfms)
385                 goto error;
386
387         for_each_possible_cpu(cpu) {
388                 struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
389                 if (!tfm)
390                         goto error;
391                 *per_cpu_ptr(tfms, cpu) = tfm;
392         }
393
394         return tfms;
395
396 error:
397         ipcomp6_free_tfms(tfms);
398         return NULL;
399 }
400
401 static void ipcomp6_free_data(struct ipcomp_data *ipcd)
402 {
403         if (ipcd->tfms)
404                 ipcomp6_free_tfms(ipcd->tfms);
405         ipcomp6_free_scratches();
406 }
407
408 static void ipcomp6_destroy(struct xfrm_state *x)
409 {
410         struct ipcomp_data *ipcd = x->data;
411         if (!ipcd)
412                 return;
413         xfrm_state_delete_tunnel(x);
414         mutex_lock(&ipcomp6_resource_mutex);
415         ipcomp6_free_data(ipcd);
416         mutex_unlock(&ipcomp6_resource_mutex);
417         kfree(ipcd);
418
419         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
420 }
421
422 static int ipcomp6_init_state(struct xfrm_state *x)
423 {
424         int err;
425         struct ipcomp_data *ipcd;
426         struct xfrm_algo_desc *calg_desc;
427
428         err = -EINVAL;
429         if (!x->calg)
430                 goto out;
431
432         if (x->encap)
433                 goto out;
434
435         err = -ENOMEM;
436         ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
437         if (!ipcd)
438                 goto out;
439
440         x->props.header_len = 0;
441         if (x->props.mode)
442                 x->props.header_len += sizeof(struct ipv6hdr);
443         
444         mutex_lock(&ipcomp6_resource_mutex);
445         if (!ipcomp6_alloc_scratches())
446                 goto error;
447
448         ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
449         if (!ipcd->tfms)
450                 goto error;
451         mutex_unlock(&ipcomp6_resource_mutex);
452
453         if (x->props.mode) {
454                 err = ipcomp6_tunnel_attach(x);
455                 if (err)
456                         goto error_tunnel;
457         }
458
459         calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
460         BUG_ON(!calg_desc);
461         ipcd->threshold = calg_desc->uinfo.comp.threshold;
462         x->data = ipcd;
463         err = 0;
464 out:
465         return err;
466 error_tunnel:
467         mutex_lock(&ipcomp6_resource_mutex);
468 error:
469         ipcomp6_free_data(ipcd);
470         mutex_unlock(&ipcomp6_resource_mutex);
471         kfree(ipcd);
472
473         goto out;
474 }
475
476 static struct xfrm_type ipcomp6_type = 
477 {
478         .description    = "IPCOMP6",
479         .owner          = THIS_MODULE,
480         .proto          = IPPROTO_COMP,
481         .init_state     = ipcomp6_init_state,
482         .destructor     = ipcomp6_destroy,
483         .input          = ipcomp6_input,
484         .output         = ipcomp6_output,
485 };
486
487 static struct inet6_protocol ipcomp6_protocol = 
488 {
489         .handler        = xfrm6_rcv,
490         .err_handler    = ipcomp6_err,
491         .flags          = INET6_PROTO_NOPOLICY,
492 };
493
494 static int __init ipcomp6_init(void)
495 {
496         if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
497                 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
498                 return -EAGAIN;
499         }
500         if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
501                 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
502                 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
503                 return -EAGAIN;
504         }
505         return 0;
506 }
507
508 static void __exit ipcomp6_fini(void)
509 {
510         if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) 
511                 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
512         if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
513                 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
514 }
515
516 module_init(ipcomp6_init);
517 module_exit(ipcomp6_fini);
518 MODULE_LICENSE("GPL");
519 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
520 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
521
522