Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 <linux/ipv6.h> |
| 51 | #include <linux/icmpv6.h> |
| 52 | |
| 53 | struct ipcomp6_tfms { |
| 54 | struct list_head list; |
| 55 | struct crypto_tfm **tfms; |
| 56 | int users; |
| 57 | }; |
| 58 | |
| 59 | static DECLARE_MUTEX(ipcomp6_resource_sem); |
| 60 | static void **ipcomp6_scratches; |
| 61 | static int ipcomp6_scratch_users; |
| 62 | static LIST_HEAD(ipcomp6_tfms_list); |
| 63 | |
| 64 | static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb) |
| 65 | { |
| 66 | int err = 0; |
| 67 | u8 nexthdr = 0; |
| 68 | int hdr_len = skb->h.raw - skb->nh.raw; |
| 69 | unsigned char *tmp_hdr = NULL; |
| 70 | struct ipv6hdr *iph; |
| 71 | int plen, dlen; |
| 72 | struct ipcomp_data *ipcd = x->data; |
| 73 | u8 *start, *scratch; |
| 74 | struct crypto_tfm *tfm; |
| 75 | int cpu; |
| 76 | |
| 77 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && |
| 78 | skb_linearize(skb, GFP_ATOMIC) != 0) { |
| 79 | err = -ENOMEM; |
| 80 | goto out; |
| 81 | } |
| 82 | |
| 83 | skb->ip_summed = CHECKSUM_NONE; |
| 84 | |
| 85 | /* Remove ipcomp header and decompress original payload */ |
| 86 | iph = skb->nh.ipv6h; |
| 87 | tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC); |
| 88 | if (!tmp_hdr) |
| 89 | goto out; |
| 90 | memcpy(tmp_hdr, iph, hdr_len); |
| 91 | nexthdr = *(u8 *)skb->data; |
| 92 | skb_pull(skb, sizeof(struct ipv6_comp_hdr)); |
| 93 | skb->nh.raw += sizeof(struct ipv6_comp_hdr); |
| 94 | memcpy(skb->nh.raw, tmp_hdr, hdr_len); |
| 95 | iph = skb->nh.ipv6h; |
| 96 | iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr)); |
| 97 | skb->h.raw = skb->data; |
| 98 | |
| 99 | /* decompression */ |
| 100 | plen = skb->len; |
| 101 | dlen = IPCOMP_SCRATCH_SIZE; |
| 102 | start = skb->data; |
| 103 | |
| 104 | cpu = get_cpu(); |
| 105 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); |
| 106 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); |
| 107 | |
| 108 | err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); |
| 109 | if (err) { |
| 110 | err = -EINVAL; |
| 111 | goto out_put_cpu; |
| 112 | } |
| 113 | |
| 114 | if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) { |
| 115 | err = -EINVAL; |
| 116 | goto out_put_cpu; |
| 117 | } |
| 118 | |
| 119 | err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); |
| 120 | if (err) { |
| 121 | goto out_put_cpu; |
| 122 | } |
| 123 | |
| 124 | skb_put(skb, dlen - plen); |
| 125 | memcpy(skb->data, scratch, dlen); |
| 126 | |
| 127 | iph = skb->nh.ipv6h; |
| 128 | iph->payload_len = htons(skb->len); |
| 129 | |
| 130 | out_put_cpu: |
| 131 | put_cpu(); |
| 132 | out: |
Jesper Juhl | a51482b | 2005-11-08 09:41:34 -0800 | [diff] [blame] | 133 | kfree(tmp_hdr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | if (err) |
| 135 | goto error_out; |
| 136 | return nexthdr; |
| 137 | error_out: |
| 138 | return err; |
| 139 | } |
| 140 | |
| 141 | static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb) |
| 142 | { |
| 143 | int err; |
| 144 | struct ipv6hdr *top_iph; |
| 145 | int hdr_len; |
| 146 | struct ipv6_comp_hdr *ipch; |
| 147 | struct ipcomp_data *ipcd = x->data; |
| 148 | int plen, dlen; |
| 149 | u8 *start, *scratch; |
| 150 | struct crypto_tfm *tfm; |
| 151 | int cpu; |
| 152 | |
| 153 | hdr_len = skb->h.raw - skb->data; |
| 154 | |
| 155 | /* check whether datagram len is larger than threshold */ |
| 156 | if ((skb->len - hdr_len) < ipcd->threshold) { |
| 157 | goto out_ok; |
| 158 | } |
| 159 | |
| 160 | if ((skb_is_nonlinear(skb) || skb_cloned(skb)) && |
| 161 | skb_linearize(skb, GFP_ATOMIC) != 0) { |
| 162 | goto out_ok; |
| 163 | } |
| 164 | |
| 165 | /* compression */ |
| 166 | plen = skb->len - hdr_len; |
| 167 | dlen = IPCOMP_SCRATCH_SIZE; |
| 168 | start = skb->h.raw; |
| 169 | |
| 170 | cpu = get_cpu(); |
| 171 | scratch = *per_cpu_ptr(ipcomp6_scratches, cpu); |
| 172 | tfm = *per_cpu_ptr(ipcd->tfms, cpu); |
| 173 | |
| 174 | err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); |
| 175 | if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) { |
| 176 | put_cpu(); |
| 177 | goto out_ok; |
| 178 | } |
| 179 | memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); |
| 180 | put_cpu(); |
| 181 | pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr)); |
| 182 | |
| 183 | /* insert ipcomp header and replace datagram */ |
| 184 | top_iph = (struct ipv6hdr *)skb->data; |
| 185 | |
| 186 | top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); |
| 187 | |
| 188 | ipch = (struct ipv6_comp_hdr *)start; |
| 189 | ipch->nexthdr = *skb->nh.raw; |
| 190 | ipch->flags = 0; |
| 191 | ipch->cpi = htons((u16 )ntohl(x->id.spi)); |
| 192 | *skb->nh.raw = IPPROTO_COMP; |
| 193 | |
| 194 | out_ok: |
| 195 | return 0; |
| 196 | } |
| 197 | |
| 198 | static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, |
| 199 | int type, int code, int offset, __u32 info) |
| 200 | { |
| 201 | u32 spi; |
| 202 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; |
| 203 | struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset); |
| 204 | struct xfrm_state *x; |
| 205 | |
| 206 | if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) |
| 207 | return; |
| 208 | |
| 209 | spi = ntohl(ntohs(ipcomph->cpi)); |
| 210 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6); |
| 211 | if (!x) |
| 212 | return; |
| 213 | |
| 214 | printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" |
| 215 | "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n", |
| 216 | spi, NIP6(iph->daddr)); |
| 217 | xfrm_state_put(x); |
| 218 | } |
| 219 | |
| 220 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) |
| 221 | { |
| 222 | struct xfrm_state *t = NULL; |
| 223 | |
| 224 | t = xfrm_state_alloc(); |
| 225 | if (!t) |
| 226 | goto out; |
| 227 | |
| 228 | t->id.proto = IPPROTO_IPV6; |
| 229 | t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr); |
| 230 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); |
| 231 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); |
| 232 | t->props.family = AF_INET6; |
| 233 | t->props.mode = 1; |
| 234 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); |
| 235 | |
Herbert Xu | 72cb696 | 2005-06-20 13:18:08 -0700 | [diff] [blame] | 236 | if (xfrm_init_state(t)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | goto error; |
| 238 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | atomic_set(&t->tunnel_users, 1); |
| 240 | |
| 241 | out: |
| 242 | return t; |
| 243 | |
| 244 | error: |
| 245 | xfrm_state_put(t); |
| 246 | goto out; |
| 247 | } |
| 248 | |
| 249 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) |
| 250 | { |
| 251 | int err = 0; |
| 252 | struct xfrm_state *t = NULL; |
| 253 | u32 spi; |
| 254 | |
| 255 | spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr); |
| 256 | if (spi) |
| 257 | t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr, |
| 258 | spi, IPPROTO_IPV6, AF_INET6); |
| 259 | if (!t) { |
| 260 | t = ipcomp6_tunnel_create(x); |
| 261 | if (!t) { |
| 262 | err = -EINVAL; |
| 263 | goto out; |
| 264 | } |
| 265 | xfrm_state_insert(t); |
| 266 | xfrm_state_hold(t); |
| 267 | } |
| 268 | x->tunnel = t; |
| 269 | atomic_inc(&t->tunnel_users); |
| 270 | |
| 271 | out: |
| 272 | return err; |
| 273 | } |
| 274 | |
| 275 | static void ipcomp6_free_scratches(void) |
| 276 | { |
| 277 | int i; |
| 278 | void **scratches; |
| 279 | |
| 280 | if (--ipcomp6_scratch_users) |
| 281 | return; |
| 282 | |
| 283 | scratches = ipcomp6_scratches; |
| 284 | if (!scratches) |
| 285 | return; |
| 286 | |
| 287 | for_each_cpu(i) { |
| 288 | void *scratch = *per_cpu_ptr(scratches, i); |
| 289 | if (scratch) |
| 290 | vfree(scratch); |
| 291 | } |
| 292 | |
| 293 | free_percpu(scratches); |
| 294 | } |
| 295 | |
| 296 | static void **ipcomp6_alloc_scratches(void) |
| 297 | { |
| 298 | int i; |
| 299 | void **scratches; |
| 300 | |
| 301 | if (ipcomp6_scratch_users++) |
| 302 | return ipcomp6_scratches; |
| 303 | |
| 304 | scratches = alloc_percpu(void *); |
| 305 | if (!scratches) |
| 306 | return NULL; |
| 307 | |
| 308 | ipcomp6_scratches = scratches; |
| 309 | |
| 310 | for_each_cpu(i) { |
| 311 | void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE); |
| 312 | if (!scratch) |
| 313 | return NULL; |
| 314 | *per_cpu_ptr(scratches, i) = scratch; |
| 315 | } |
| 316 | |
| 317 | return scratches; |
| 318 | } |
| 319 | |
| 320 | static void ipcomp6_free_tfms(struct crypto_tfm **tfms) |
| 321 | { |
| 322 | struct ipcomp6_tfms *pos; |
| 323 | int cpu; |
| 324 | |
| 325 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { |
| 326 | if (pos->tfms == tfms) |
| 327 | break; |
| 328 | } |
| 329 | |
| 330 | BUG_TRAP(pos); |
| 331 | |
| 332 | if (--pos->users) |
| 333 | return; |
| 334 | |
| 335 | list_del(&pos->list); |
| 336 | kfree(pos); |
| 337 | |
| 338 | if (!tfms) |
| 339 | return; |
| 340 | |
| 341 | for_each_cpu(cpu) { |
| 342 | struct crypto_tfm *tfm = *per_cpu_ptr(tfms, cpu); |
Jesper Juhl | 573dbd9 | 2005-09-01 17:44:29 -0700 | [diff] [blame] | 343 | crypto_free_tfm(tfm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | } |
| 345 | free_percpu(tfms); |
| 346 | } |
| 347 | |
| 348 | static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name) |
| 349 | { |
| 350 | struct ipcomp6_tfms *pos; |
| 351 | struct crypto_tfm **tfms; |
| 352 | int cpu; |
| 353 | |
| 354 | /* This can be any valid CPU ID so we don't need locking. */ |
Herbert Xu | 6fc8b9e | 2005-08-18 14:36:59 -0700 | [diff] [blame] | 355 | cpu = raw_smp_processor_id(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | |
| 357 | list_for_each_entry(pos, &ipcomp6_tfms_list, list) { |
| 358 | struct crypto_tfm *tfm; |
| 359 | |
| 360 | tfms = pos->tfms; |
| 361 | tfm = *per_cpu_ptr(tfms, cpu); |
| 362 | |
| 363 | if (!strcmp(crypto_tfm_alg_name(tfm), alg_name)) { |
| 364 | pos->users++; |
| 365 | return tfms; |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | pos = kmalloc(sizeof(*pos), GFP_KERNEL); |
| 370 | if (!pos) |
| 371 | return NULL; |
| 372 | |
| 373 | pos->users = 1; |
| 374 | INIT_LIST_HEAD(&pos->list); |
| 375 | list_add(&pos->list, &ipcomp6_tfms_list); |
| 376 | |
| 377 | pos->tfms = tfms = alloc_percpu(struct crypto_tfm *); |
| 378 | if (!tfms) |
| 379 | goto error; |
| 380 | |
| 381 | for_each_cpu(cpu) { |
| 382 | struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0); |
| 383 | if (!tfm) |
| 384 | goto error; |
| 385 | *per_cpu_ptr(tfms, cpu) = tfm; |
| 386 | } |
| 387 | |
| 388 | return tfms; |
| 389 | |
| 390 | error: |
| 391 | ipcomp6_free_tfms(tfms); |
| 392 | return NULL; |
| 393 | } |
| 394 | |
| 395 | static void ipcomp6_free_data(struct ipcomp_data *ipcd) |
| 396 | { |
| 397 | if (ipcd->tfms) |
| 398 | ipcomp6_free_tfms(ipcd->tfms); |
| 399 | ipcomp6_free_scratches(); |
| 400 | } |
| 401 | |
| 402 | static void ipcomp6_destroy(struct xfrm_state *x) |
| 403 | { |
| 404 | struct ipcomp_data *ipcd = x->data; |
| 405 | if (!ipcd) |
| 406 | return; |
| 407 | xfrm_state_delete_tunnel(x); |
| 408 | down(&ipcomp6_resource_sem); |
| 409 | ipcomp6_free_data(ipcd); |
| 410 | up(&ipcomp6_resource_sem); |
| 411 | kfree(ipcd); |
| 412 | |
| 413 | xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr); |
| 414 | } |
| 415 | |
Herbert Xu | 72cb696 | 2005-06-20 13:18:08 -0700 | [diff] [blame] | 416 | static int ipcomp6_init_state(struct xfrm_state *x) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | { |
| 418 | int err; |
| 419 | struct ipcomp_data *ipcd; |
| 420 | struct xfrm_algo_desc *calg_desc; |
| 421 | |
| 422 | err = -EINVAL; |
| 423 | if (!x->calg) |
| 424 | goto out; |
| 425 | |
| 426 | if (x->encap) |
| 427 | goto out; |
| 428 | |
| 429 | err = -ENOMEM; |
| 430 | ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL); |
| 431 | if (!ipcd) |
| 432 | goto out; |
| 433 | |
| 434 | memset(ipcd, 0, sizeof(*ipcd)); |
| 435 | x->props.header_len = 0; |
| 436 | if (x->props.mode) |
| 437 | x->props.header_len += sizeof(struct ipv6hdr); |
| 438 | |
| 439 | down(&ipcomp6_resource_sem); |
| 440 | if (!ipcomp6_alloc_scratches()) |
| 441 | goto error; |
| 442 | |
| 443 | ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name); |
| 444 | if (!ipcd->tfms) |
| 445 | goto error; |
| 446 | up(&ipcomp6_resource_sem); |
| 447 | |
| 448 | if (x->props.mode) { |
| 449 | err = ipcomp6_tunnel_attach(x); |
| 450 | if (err) |
| 451 | goto error_tunnel; |
| 452 | } |
| 453 | |
| 454 | calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0); |
| 455 | BUG_ON(!calg_desc); |
| 456 | ipcd->threshold = calg_desc->uinfo.comp.threshold; |
| 457 | x->data = ipcd; |
| 458 | err = 0; |
| 459 | out: |
| 460 | return err; |
| 461 | error_tunnel: |
| 462 | down(&ipcomp6_resource_sem); |
| 463 | error: |
| 464 | ipcomp6_free_data(ipcd); |
| 465 | up(&ipcomp6_resource_sem); |
| 466 | kfree(ipcd); |
| 467 | |
| 468 | goto out; |
| 469 | } |
| 470 | |
| 471 | static struct xfrm_type ipcomp6_type = |
| 472 | { |
| 473 | .description = "IPCOMP6", |
| 474 | .owner = THIS_MODULE, |
| 475 | .proto = IPPROTO_COMP, |
| 476 | .init_state = ipcomp6_init_state, |
| 477 | .destructor = ipcomp6_destroy, |
| 478 | .input = ipcomp6_input, |
| 479 | .output = ipcomp6_output, |
| 480 | }; |
| 481 | |
| 482 | static struct inet6_protocol ipcomp6_protocol = |
| 483 | { |
| 484 | .handler = xfrm6_rcv, |
| 485 | .err_handler = ipcomp6_err, |
| 486 | .flags = INET6_PROTO_NOPOLICY, |
| 487 | }; |
| 488 | |
| 489 | static int __init ipcomp6_init(void) |
| 490 | { |
| 491 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { |
| 492 | printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n"); |
| 493 | return -EAGAIN; |
| 494 | } |
| 495 | if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { |
| 496 | printk(KERN_INFO "ipcomp6 init: can't add protocol\n"); |
| 497 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); |
| 498 | return -EAGAIN; |
| 499 | } |
| 500 | return 0; |
| 501 | } |
| 502 | |
| 503 | static void __exit ipcomp6_fini(void) |
| 504 | { |
| 505 | if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) |
| 506 | printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n"); |
| 507 | if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) |
| 508 | printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n"); |
| 509 | } |
| 510 | |
| 511 | module_init(ipcomp6_init); |
| 512 | module_exit(ipcomp6_fini); |
| 513 | MODULE_LICENSE("GPL"); |
| 514 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); |
| 515 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); |
| 516 | |
| 517 | |