blob: d64e2ec8da7b454f0bd6bc273c9b4fde707fcb9e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IP Payload Compression Protocol (IPComp) - RFC3173.
3 *
4 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 * Todo:
12 * - Tunable compression parameters.
13 * - Compression stats.
14 * - Adaptive compression.
15 */
16#include <linux/config.h>
17#include <linux/module.h>
18#include <asm/scatterlist.h>
19#include <asm/semaphore.h>
20#include <linux/crypto.h>
21#include <linux/pfkeyv2.h>
22#include <linux/percpu.h>
23#include <linux/smp.h>
24#include <linux/list.h>
25#include <linux/vmalloc.h>
26#include <linux/rtnetlink.h>
27#include <net/ip.h>
28#include <net/xfrm.h>
29#include <net/icmp.h>
30#include <net/ipcomp.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020031#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33struct ipcomp_tfms {
34 struct list_head list;
35 struct crypto_tfm **tfms;
36 int users;
37};
38
39static DECLARE_MUTEX(ipcomp_resource_sem);
40static void **ipcomp_scratches;
41static int ipcomp_scratch_users;
42static LIST_HEAD(ipcomp_tfms_list);
43
44static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
45{
46 int err, plen, dlen;
47 struct iphdr *iph;
48 struct ipcomp_data *ipcd = x->data;
49 u8 *start, *scratch;
50 struct crypto_tfm *tfm;
51 int cpu;
52
53 plen = skb->len;
54 dlen = IPCOMP_SCRATCH_SIZE;
55 start = skb->data;
56
57 cpu = get_cpu();
58 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
59 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
60
61 err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
62 if (err)
63 goto out;
64
65 if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
66 err = -EINVAL;
67 goto out;
68 }
69
70 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
71 if (err)
72 goto out;
73
74 skb_put(skb, dlen - plen);
75 memcpy(skb->data, scratch, dlen);
76 iph = skb->nh.iph;
77 iph->tot_len = htons(dlen + iph->ihl * 4);
78out:
79 put_cpu();
80 return err;
81}
82
83static int ipcomp_input(struct xfrm_state *x,
84 struct xfrm_decap_state *decap, struct sk_buff *skb)
85{
86 u8 nexthdr;
87 int err = 0;
88 struct iphdr *iph;
89 union {
90 struct iphdr iph;
91 char buf[60];
92 } tmp_iph;
93
94
95 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
96 skb_linearize(skb, GFP_ATOMIC) != 0) {
97 err = -ENOMEM;
98 goto out;
99 }
100
101 skb->ip_summed = CHECKSUM_NONE;
102
103 /* Remove ipcomp header and decompress original payload */
104 iph = skb->nh.iph;
105 memcpy(&tmp_iph, iph, iph->ihl * 4);
106 nexthdr = *(u8 *)skb->data;
107 skb_pull(skb, sizeof(struct ip_comp_hdr));
108 skb->nh.raw += sizeof(struct ip_comp_hdr);
109 memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
110 iph = skb->nh.iph;
111 iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ip_comp_hdr));
112 iph->protocol = nexthdr;
113 skb->h.raw = skb->data;
114 err = ipcomp_decompress(x, skb);
115
116out:
117 return err;
118}
119
120static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
121{
122 int err, plen, dlen, ihlen;
123 struct iphdr *iph = skb->nh.iph;
124 struct ipcomp_data *ipcd = x->data;
125 u8 *start, *scratch;
126 struct crypto_tfm *tfm;
127 int cpu;
128
129 ihlen = iph->ihl * 4;
130 plen = skb->len - ihlen;
131 dlen = IPCOMP_SCRATCH_SIZE;
132 start = skb->data + ihlen;
133
134 cpu = get_cpu();
135 scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
136 tfm = *per_cpu_ptr(ipcd->tfms, cpu);
137
138 err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);
139 if (err)
140 goto out;
141
142 if ((dlen + sizeof(struct ip_comp_hdr)) >= plen) {
143 err = -EMSGSIZE;
144 goto out;
145 }
146
147 memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
148 put_cpu();
149
150 pskb_trim(skb, ihlen + dlen + sizeof(struct ip_comp_hdr));
151 return 0;
152
153out:
154 put_cpu();
155 return err;
156}
157
158static int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb)
159{
160 int err;
161 struct iphdr *iph;
162 struct ip_comp_hdr *ipch;
163 struct ipcomp_data *ipcd = x->data;
164 int hdr_len = 0;
165
166 iph = skb->nh.iph;
167 iph->tot_len = htons(skb->len);
168 hdr_len = iph->ihl * 4;
169 if ((skb->len - hdr_len) < ipcd->threshold) {
170 /* Don't bother compressing */
171 goto out_ok;
172 }
173
174 if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
175 skb_linearize(skb, GFP_ATOMIC) != 0) {
176 goto out_ok;
177 }
178
179 err = ipcomp_compress(x, skb);
180 iph = skb->nh.iph;
181
182 if (err) {
183 goto out_ok;
184 }
185
186 /* Install ipcomp header, convert into ipcomp datagram. */
187 iph->tot_len = htons(skb->len);
188 ipch = (struct ip_comp_hdr *)((char *)iph + iph->ihl * 4);
189 ipch->nexthdr = iph->protocol;
190 ipch->flags = 0;
191 ipch->cpi = htons((u16 )ntohl(x->id.spi));
192 iph->protocol = IPPROTO_COMP;
193 ip_send_check(iph);
194 return 0;
195
196out_ok:
197 if (x->props.mode)
198 ip_send_check(iph);
199 return 0;
200}
201
202static void ipcomp4_err(struct sk_buff *skb, u32 info)
203{
204 u32 spi;
205 struct iphdr *iph = (struct iphdr *)skb->data;
206 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
207 struct xfrm_state *x;
208
209 if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
210 skb->h.icmph->code != ICMP_FRAG_NEEDED)
211 return;
212
213 spi = ntohl(ntohs(ipch->cpi));
214 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
215 spi, IPPROTO_COMP, AF_INET);
216 if (!x)
217 return;
Patrick McHardy64ce2072005-08-09 20:50:53 -0700218 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
219 spi, NIPQUAD(iph->daddr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 xfrm_state_put(x);
221}
222
223/* We always hold one tunnel user reference to indicate a tunnel */
224static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
225{
226 struct xfrm_state *t;
227
228 t = xfrm_state_alloc();
229 if (t == NULL)
230 goto out;
231
232 t->id.proto = IPPROTO_IPIP;
233 t->id.spi = x->props.saddr.a4;
234 t->id.daddr.a4 = x->id.daddr.a4;
235 memcpy(&t->sel, &x->sel, sizeof(t->sel));
236 t->props.family = AF_INET;
237 t->props.mode = 1;
238 t->props.saddr.a4 = x->props.saddr.a4;
239 t->props.flags = x->props.flags;
Herbert Xu72cb6962005-06-20 13:18:08 -0700240
241 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 goto error;
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 atomic_set(&t->tunnel_users, 1);
245out:
246 return t;
247
248error:
249 t->km.state = XFRM_STATE_DEAD;
250 xfrm_state_put(t);
251 t = NULL;
252 goto out;
253}
254
255/*
256 * Must be protected by xfrm_cfg_sem. State and tunnel user references are
257 * always incremented on success.
258 */
259static int ipcomp_tunnel_attach(struct xfrm_state *x)
260{
261 int err = 0;
262 struct xfrm_state *t;
263
264 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
265 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
266 if (!t) {
267 t = ipcomp_tunnel_create(x);
268 if (!t) {
269 err = -EINVAL;
270 goto out;
271 }
272 xfrm_state_insert(t);
273 xfrm_state_hold(t);
274 }
275 x->tunnel = t;
276 atomic_inc(&t->tunnel_users);
277out:
278 return err;
279}
280
281static void ipcomp_free_scratches(void)
282{
283 int i;
284 void **scratches;
285
286 if (--ipcomp_scratch_users)
287 return;
288
289 scratches = ipcomp_scratches;
290 if (!scratches)
291 return;
292
293 for_each_cpu(i) {
294 void *scratch = *per_cpu_ptr(scratches, i);
295 if (scratch)
296 vfree(scratch);
297 }
298
299 free_percpu(scratches);
300}
301
302static void **ipcomp_alloc_scratches(void)
303{
304 int i;
305 void **scratches;
306
307 if (ipcomp_scratch_users++)
308 return ipcomp_scratches;
309
310 scratches = alloc_percpu(void *);
311 if (!scratches)
312 return NULL;
313
314 ipcomp_scratches = scratches;
315
316 for_each_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
326static void ipcomp_free_tfms(struct crypto_tfm **tfms)
327{
328 struct ipcomp_tfms *pos;
329 int cpu;
330
331 list_for_each_entry(pos, &ipcomp_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_cpu(cpu) {
348 struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700349 crypto_free_tfm(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 }
351 free_percpu(tfms);
352}
353
354static struct crypto_tfm **ipcomp_alloc_tfms(const char *alg_name)
355{
356 struct ipcomp_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. */
Herbert Xu6fc8b9e2005-08-18 14:36:59 -0700361 cpu = raw_smp_processor_id();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
363 list_for_each_entry(pos, &ipcomp_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, &ipcomp_tfms_list);
382
383 pos->tfms = tfms = alloc_percpu(struct crypto_tfm *);
384 if (!tfms)
385 goto error;
386
387 for_each_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
396error:
397 ipcomp_free_tfms(tfms);
398 return NULL;
399}
400
401static void ipcomp_free_data(struct ipcomp_data *ipcd)
402{
403 if (ipcd->tfms)
404 ipcomp_free_tfms(ipcd->tfms);
405 ipcomp_free_scratches();
406}
407
408static void ipcomp_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 down(&ipcomp_resource_sem);
415 ipcomp_free_data(ipcd);
416 up(&ipcomp_resource_sem);
417 kfree(ipcd);
418}
419
Herbert Xu72cb6962005-06-20 13:18:08 -0700420static int ipcomp_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421{
422 int err;
423 struct ipcomp_data *ipcd;
424 struct xfrm_algo_desc *calg_desc;
425
426 err = -EINVAL;
427 if (!x->calg)
428 goto out;
429
430 if (x->encap)
431 goto out;
432
433 err = -ENOMEM;
434 ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
435 if (!ipcd)
436 goto out;
437
438 memset(ipcd, 0, sizeof(*ipcd));
439 x->props.header_len = 0;
440 if (x->props.mode)
441 x->props.header_len += sizeof(struct iphdr);
442
443 down(&ipcomp_resource_sem);
444 if (!ipcomp_alloc_scratches())
445 goto error;
446
447 ipcd->tfms = ipcomp_alloc_tfms(x->calg->alg_name);
448 if (!ipcd->tfms)
449 goto error;
450 up(&ipcomp_resource_sem);
451
452 if (x->props.mode) {
453 err = ipcomp_tunnel_attach(x);
454 if (err)
455 goto error_tunnel;
456 }
457
458 calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);
459 BUG_ON(!calg_desc);
460 ipcd->threshold = calg_desc->uinfo.comp.threshold;
461 x->data = ipcd;
462 err = 0;
463out:
464 return err;
465
466error_tunnel:
467 down(&ipcomp_resource_sem);
468error:
469 ipcomp_free_data(ipcd);
470 up(&ipcomp_resource_sem);
471 kfree(ipcd);
472 goto out;
473}
474
475static struct xfrm_type ipcomp_type = {
476 .description = "IPCOMP4",
477 .owner = THIS_MODULE,
478 .proto = IPPROTO_COMP,
479 .init_state = ipcomp_init_state,
480 .destructor = ipcomp_destroy,
481 .input = ipcomp_input,
482 .output = ipcomp_output
483};
484
485static struct net_protocol ipcomp4_protocol = {
486 .handler = xfrm4_rcv,
487 .err_handler = ipcomp4_err,
488 .no_policy = 1,
489};
490
491static int __init ipcomp4_init(void)
492{
493 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
494 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
495 return -EAGAIN;
496 }
497 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
498 printk(KERN_INFO "ipcomp init: can't add protocol\n");
499 xfrm_unregister_type(&ipcomp_type, AF_INET);
500 return -EAGAIN;
501 }
502 return 0;
503}
504
505static void __exit ipcomp4_fini(void)
506{
507 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
508 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
509 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
510 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
511}
512
513module_init(ipcomp4_init);
514module_exit(ipcomp4_fini);
515
516MODULE_LICENSE("GPL");
517MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3173");
518MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
519