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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [net/] [ipv6/] [ipcomp6.c] - Blame information for rev 17

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1 3 xianfeng
/*
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/module.h>
34
#include <net/ip.h>
35
#include <net/xfrm.h>
36
#include <net/ipcomp.h>
37
#include <asm/semaphore.h>
38
#include <linux/crypto.h>
39
#include <linux/err.h>
40
#include <linux/pfkeyv2.h>
41
#include <linux/random.h>
42
#include <linux/percpu.h>
43
#include <linux/smp.h>
44
#include <linux/list.h>
45
#include <linux/vmalloc.h>
46
#include <linux/rtnetlink.h>
47
#include <net/icmp.h>
48
#include <net/ipv6.h>
49
#include <net/protocol.h>
50
#include <linux/ipv6.h>
51
#include <linux/icmpv6.h>
52
#include <linux/mutex.h>
53
 
54
struct ipcomp6_tfms {
55
        struct list_head list;
56
        struct crypto_comp **tfms;
57
        int users;
58
};
59
 
60
static DEFINE_MUTEX(ipcomp6_resource_mutex);
61
static void **ipcomp6_scratches;
62
static int ipcomp6_scratch_users;
63
static LIST_HEAD(ipcomp6_tfms_list);
64
 
65
static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb)
66
{
67
        int err = -ENOMEM;
68
        struct ip_comp_hdr *ipch;
69
        int plen, dlen;
70
        struct ipcomp_data *ipcd = x->data;
71
        u8 *start, *scratch;
72
        struct crypto_comp *tfm;
73
        int cpu;
74
 
75
        if (skb_linearize_cow(skb))
76
                goto out;
77
 
78
        skb->ip_summed = CHECKSUM_NONE;
79
 
80
        /* Remove ipcomp header and decompress original payload */
81
        ipch = (void *)skb->data;
82
        skb->transport_header = skb->network_header + sizeof(*ipch);
83
        __skb_pull(skb, sizeof(*ipch));
84
 
85
        /* decompression */
86
        plen = skb->len;
87
        dlen = IPCOMP_SCRATCH_SIZE;
88
        start = skb->data;
89
 
90
        cpu = get_cpu();
91
        scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
92
        tfm = *per_cpu_ptr(ipcd->tfms, cpu);
93
 
94
        err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
95
        if (err)
96
                goto out_put_cpu;
97
 
98
        if (dlen < (plen + sizeof(*ipch))) {
99
                err = -EINVAL;
100
                goto out_put_cpu;
101
        }
102
 
103
        err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
104
        if (err) {
105
                goto out_put_cpu;
106
        }
107
 
108
        skb->truesize += dlen - plen;
109
        __skb_put(skb, dlen - plen);
110
        skb_copy_to_linear_data(skb, scratch, dlen);
111
        err = ipch->nexthdr;
112
 
113
out_put_cpu:
114
        put_cpu();
115
out:
116
        return err;
117
}
118
 
119
static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb)
120
{
121
        int err;
122
        struct ip_comp_hdr *ipch;
123
        struct ipcomp_data *ipcd = x->data;
124
        int plen, dlen;
125
        u8 *start, *scratch;
126
        struct crypto_comp *tfm;
127
        int cpu;
128
 
129
        /* check whether datagram len is larger than threshold */
130
        if (skb->len < ipcd->threshold) {
131
                goto out_ok;
132
        }
133
 
134
        if (skb_linearize_cow(skb))
135
                goto out_ok;
136
 
137
        /* compression */
138
        plen = skb->len;
139
        dlen = IPCOMP_SCRATCH_SIZE;
140
        start = skb->data;
141
 
142
        cpu = get_cpu();
143
        scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);
144
        tfm = *per_cpu_ptr(ipcd->tfms, cpu);
145
 
146
        err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
147
        if (err || (dlen + sizeof(*ipch)) >= plen) {
148
                put_cpu();
149
                goto out_ok;
150
        }
151
        memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
152
        put_cpu();
153
        pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
154
 
155
        /* insert ipcomp header and replace datagram */
156
        ipch = ip_comp_hdr(skb);
157
        ipch->nexthdr = *skb_mac_header(skb);
158
        ipch->flags = 0;
159
        ipch->cpi = htons((u16 )ntohl(x->id.spi));
160
        *skb_mac_header(skb) = IPPROTO_COMP;
161
 
162
out_ok:
163
        skb_push(skb, -skb_network_offset(skb));
164
 
165
        return 0;
166
}
167
 
168
static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
169
                                int type, int code, int offset, __be32 info)
170
{
171
        __be32 spi;
172
        struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
173
        struct ip_comp_hdr *ipcomph =
174
                (struct ip_comp_hdr *)(skb->data + offset);
175
        struct xfrm_state *x;
176
 
177
        if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
178
                return;
179
 
180
        spi = htonl(ntohs(ipcomph->cpi));
181
        x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
182
        if (!x)
183
                return;
184
 
185
        printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",
186
                        spi, NIP6(iph->daddr));
187
        xfrm_state_put(x);
188
}
189
 
190
static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
191
{
192
        struct xfrm_state *t = NULL;
193
        u8 mode = XFRM_MODE_TUNNEL;
194
 
195
        t = xfrm_state_alloc();
196
        if (!t)
197
                goto out;
198
 
199
        t->id.proto = IPPROTO_IPV6;
200
        t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
201
        if (!t->id.spi)
202
                goto error;
203
 
204
        memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
205
        memcpy(&t->sel, &x->sel, sizeof(t->sel));
206
        t->props.family = AF_INET6;
207
        if (x->props.mode == XFRM_MODE_BEET)
208
                mode = x->props.mode;
209
        t->props.mode = mode;
210
        memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
211
 
212
        if (xfrm_init_state(t))
213
                goto error;
214
 
215
        atomic_set(&t->tunnel_users, 1);
216
 
217
out:
218
        return t;
219
 
220
error:
221
        t->km.state = XFRM_STATE_DEAD;
222
        xfrm_state_put(t);
223
        t = NULL;
224
        goto out;
225
}
226
 
227
static int ipcomp6_tunnel_attach(struct xfrm_state *x)
228
{
229
        int err = 0;
230
        struct xfrm_state *t = NULL;
231
        __be32 spi;
232
 
233
        spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
234
        if (spi)
235
                t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,
236
                                              spi, IPPROTO_IPV6, AF_INET6);
237
        if (!t) {
238
                t = ipcomp6_tunnel_create(x);
239
                if (!t) {
240
                        err = -EINVAL;
241
                        goto out;
242
                }
243
                xfrm_state_insert(t);
244
                xfrm_state_hold(t);
245
        }
246
        x->tunnel = t;
247
        atomic_inc(&t->tunnel_users);
248
 
249
out:
250
        return err;
251
}
252
 
253
static void ipcomp6_free_scratches(void)
254
{
255
        int i;
256
        void **scratches;
257
 
258
        if (--ipcomp6_scratch_users)
259
                return;
260
 
261
        scratches = ipcomp6_scratches;
262
        if (!scratches)
263
                return;
264
 
265
        for_each_possible_cpu(i) {
266
                void *scratch = *per_cpu_ptr(scratches, i);
267
 
268
                vfree(scratch);
269
        }
270
 
271
        free_percpu(scratches);
272
}
273
 
274
static void **ipcomp6_alloc_scratches(void)
275
{
276
        int i;
277
        void **scratches;
278
 
279
        if (ipcomp6_scratch_users++)
280
                return ipcomp6_scratches;
281
 
282
        scratches = alloc_percpu(void *);
283
        if (!scratches)
284
                return NULL;
285
 
286
        ipcomp6_scratches = scratches;
287
 
288
        for_each_possible_cpu(i) {
289
                void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);
290
                if (!scratch)
291
                        return NULL;
292
                *per_cpu_ptr(scratches, i) = scratch;
293
        }
294
 
295
        return scratches;
296
}
297
 
298
static void ipcomp6_free_tfms(struct crypto_comp **tfms)
299
{
300
        struct ipcomp6_tfms *pos;
301
        int cpu;
302
 
303
        list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
304
                if (pos->tfms == tfms)
305
                        break;
306
        }
307
 
308
        BUG_TRAP(pos);
309
 
310
        if (--pos->users)
311
                return;
312
 
313
        list_del(&pos->list);
314
        kfree(pos);
315
 
316
        if (!tfms)
317
                return;
318
 
319
        for_each_possible_cpu(cpu) {
320
                struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);
321
                crypto_free_comp(tfm);
322
        }
323
        free_percpu(tfms);
324
}
325
 
326
static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name)
327
{
328
        struct ipcomp6_tfms *pos;
329
        struct crypto_comp **tfms;
330
        int cpu;
331
 
332
        /* This can be any valid CPU ID so we don't need locking. */
333
        cpu = raw_smp_processor_id();
334
 
335
        list_for_each_entry(pos, &ipcomp6_tfms_list, list) {
336
                struct crypto_comp *tfm;
337
 
338
                tfms = pos->tfms;
339
                tfm = *per_cpu_ptr(tfms, cpu);
340
 
341
                if (!strcmp(crypto_comp_name(tfm), alg_name)) {
342
                        pos->users++;
343
                        return tfms;
344
                }
345
        }
346
 
347
        pos = kmalloc(sizeof(*pos), GFP_KERNEL);
348
        if (!pos)
349
                return NULL;
350
 
351
        pos->users = 1;
352
        INIT_LIST_HEAD(&pos->list);
353
        list_add(&pos->list, &ipcomp6_tfms_list);
354
 
355
        pos->tfms = tfms = alloc_percpu(struct crypto_comp *);
356
        if (!tfms)
357
                goto error;
358
 
359
        for_each_possible_cpu(cpu) {
360
                struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,
361
                                                            CRYPTO_ALG_ASYNC);
362
                if (IS_ERR(tfm))
363
                        goto error;
364
                *per_cpu_ptr(tfms, cpu) = tfm;
365
        }
366
 
367
        return tfms;
368
 
369
error:
370
        ipcomp6_free_tfms(tfms);
371
        return NULL;
372
}
373
 
374
static void ipcomp6_free_data(struct ipcomp_data *ipcd)
375
{
376
        if (ipcd->tfms)
377
                ipcomp6_free_tfms(ipcd->tfms);
378
        ipcomp6_free_scratches();
379
}
380
 
381
static void ipcomp6_destroy(struct xfrm_state *x)
382
{
383
        struct ipcomp_data *ipcd = x->data;
384
        if (!ipcd)
385
                return;
386
        xfrm_state_delete_tunnel(x);
387
        mutex_lock(&ipcomp6_resource_mutex);
388
        ipcomp6_free_data(ipcd);
389
        mutex_unlock(&ipcomp6_resource_mutex);
390
        kfree(ipcd);
391
 
392
        xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
393
}
394
 
395
static int ipcomp6_init_state(struct xfrm_state *x)
396
{
397
        int err;
398
        struct ipcomp_data *ipcd;
399
        struct xfrm_algo_desc *calg_desc;
400
 
401
        err = -EINVAL;
402
        if (!x->calg)
403
                goto out;
404
 
405
        if (x->encap)
406
                goto out;
407
 
408
        err = -ENOMEM;
409
        ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
410
        if (!ipcd)
411
                goto out;
412
 
413
        x->props.header_len = 0;
414
        switch (x->props.mode) {
415
        case XFRM_MODE_BEET:
416
        case XFRM_MODE_TRANSPORT:
417
                break;
418
        case XFRM_MODE_TUNNEL:
419
                x->props.header_len += sizeof(struct ipv6hdr);
420
        default:
421
                goto error;
422
        }
423
 
424
        mutex_lock(&ipcomp6_resource_mutex);
425
        if (!ipcomp6_alloc_scratches())
426
                goto error;
427
 
428
        ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
429
        if (!ipcd->tfms)
430
                goto error;
431
        mutex_unlock(&ipcomp6_resource_mutex);
432
 
433
        if (x->props.mode == XFRM_MODE_TUNNEL) {
434
                err = ipcomp6_tunnel_attach(x);
435
                if (err)
436
                        goto error_tunnel;
437
        }
438
 
439
        calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
440
        BUG_ON(!calg_desc);
441
        ipcd->threshold = calg_desc->uinfo.comp.threshold;
442
        x->data = ipcd;
443
        err = 0;
444
out:
445
        return err;
446
error_tunnel:
447
        mutex_lock(&ipcomp6_resource_mutex);
448
error:
449
        ipcomp6_free_data(ipcd);
450
        mutex_unlock(&ipcomp6_resource_mutex);
451
        kfree(ipcd);
452
 
453
        goto out;
454
}
455
 
456
static struct xfrm_type ipcomp6_type =
457
{
458
        .description    = "IPCOMP6",
459
        .owner          = THIS_MODULE,
460
        .proto          = IPPROTO_COMP,
461
        .init_state     = ipcomp6_init_state,
462
        .destructor     = ipcomp6_destroy,
463
        .input          = ipcomp6_input,
464
        .output         = ipcomp6_output,
465
        .hdr_offset     = xfrm6_find_1stfragopt,
466
};
467
 
468
static struct inet6_protocol ipcomp6_protocol =
469
{
470
        .handler        = xfrm6_rcv,
471
        .err_handler    = ipcomp6_err,
472
        .flags          = INET6_PROTO_NOPOLICY,
473
};
474
 
475
static int __init ipcomp6_init(void)
476
{
477
        if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
478
                printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
479
                return -EAGAIN;
480
        }
481
        if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
482
                printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
483
                xfrm_unregister_type(&ipcomp6_type, AF_INET6);
484
                return -EAGAIN;
485
        }
486
        return 0;
487
}
488
 
489
static void __exit ipcomp6_fini(void)
490
{
491
        if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
492
                printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
493
        if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
494
                printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
495
}
496
 
497
module_init(ipcomp6_init);
498
module_exit(ipcomp6_fini);
499
MODULE_LICENSE("GPL");
500
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
501
MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
502
 
503
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);

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