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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
54struct ipcomp6_tfms {
55 struct list_head list;
56 struct crypto_comp **tfms;
57 int users;
58};
59
60static DEFINE_MUTEX(ipcomp6_resource_mutex);
61static void **ipcomp6_scratches;
62static int ipcomp6_scratch_users;
63static LIST_HEAD(ipcomp6_tfms_list);
64
65static 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
81 ipch = (void *)skb->data;
82 skb->transport_header = skb->network_header + sizeof(*ipch);
83 __skb_pull(skb, sizeof(*ipch));
84
85
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
113out_put_cpu:
114 put_cpu();
115out:
116 return err;
117}
118
119static 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
130 if (skb->len < ipcd->threshold) {
131 goto out_ok;
132 }
133
134 if (skb_linearize_cow(skb))
135 goto out_ok;
136
137
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
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
162out_ok:
163 skb_push(skb, -skb_network_offset(skb));
164
165 return 0;
166}
167
168static 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
190static 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
217out:
218 return t;
219
220error:
221 t->km.state = XFRM_STATE_DEAD;
222 xfrm_state_put(t);
223 t = NULL;
224 goto out;
225}
226
227static 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
249out:
250 return err;
251}
252
253static 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
274static 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
298static 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
326static 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
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
369error:
370 ipcomp6_free_tfms(tfms);
371 return NULL;
372}
373
374static 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
381static 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
395static 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;
444out:
445 return err;
446error_tunnel:
447 mutex_lock(&ipcomp6_resource_mutex);
448error:
449 ipcomp6_free_data(ipcd);
450 mutex_unlock(&ipcomp6_resource_mutex);
451 kfree(ipcd);
452
453 goto out;
454}
455
456static 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
468static struct inet6_protocol ipcomp6_protocol =
469{
470 .handler = xfrm6_rcv,
471 .err_handler = ipcomp6_err,
472 .flags = INET6_PROTO_NOPOLICY,
473};
474
475static 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
489static 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
497module_init(ipcomp6_init);
498module_exit(ipcomp6_fini);
499MODULE_LICENSE("GPL");
500MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
501MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
502
503MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);
504
