net/ipv6/xfrm6_tunnel.c

   1 /*
   2  * Copyright (C)2003,2004 USAGI/WIDE Project
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  * Authors      Mitsuru KANDA  <mk@linux-ipv6.org>
  19  *              YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
  20  *
  21  * Based on net/ipv4/xfrm4_tunnel.c
  22  *
  23  */
  24 #include <linux/config.h>
  25 #include <linux/module.h>
  26 #include <linux/xfrm.h>
  27 #include <linux/list.h>
  28 #include <net/ip.h>
  29 #include <net/xfrm.h>
  30 #include <net/ipv6.h>
  31 #include <net/protocol.h>
  32 #include <linux/ipv6.h>
  33 #include <linux/icmpv6.h>
  34 #include <linux/mutex.h>
  35
  36 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
  37 # define X6TDEBUG       3
  38 #else
  39 # define X6TDEBUG       1
  40 #endif
  41
  42 #define X6TPRINTK(fmt, args...)         printk(fmt, ## args)
  43 #define X6TNOPRINTK(fmt, args...)       do { ; } while(0)
  44
  45 #if X6TDEBUG >= 1
  46 # define X6TPRINTK1     X6TPRINTK
  47 #else
  48 # define X6TPRINTK1     X6TNOPRINTK
  49 #endif
  50
  51 #if X6TDEBUG >= 3
  52 # define X6TPRINTK3     X6TPRINTK
  53 #else
  54 # define X6TPRINTK3     X6TNOPRINTK
  55 #endif
  56
  57 /*
  58  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  59  * per xfrm_address_t.
  60  */
  61 struct xfrm6_tunnel_spi {
  62         struct hlist_node list_byaddr;
  63         struct hlist_node list_byspi;
  64         xfrm_address_t addr;
  65         u32 spi;
  66         atomic_t refcnt;
  67 #ifdef XFRM6_TUNNEL_SPI_MAGIC
  68         u32 magic;
  69 #endif
  70 };
  71
  72 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
  73 # define XFRM6_TUNNEL_SPI_MAGIC 0xdeadbeef
  74 #endif
  75
  76 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
  77
  78 static u32 xfrm6_tunnel_spi;
  79
  80 #define XFRM6_TUNNEL_SPI_MIN    1
  81 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  82
  83 static kmem_cache_t *xfrm6_tunnel_spi_kmem __read_mostly;
  84
  85 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  86 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  87
  88 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  89 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  90
  91 #ifdef XFRM6_TUNNEL_SPI_MAGIC
  92 static int x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
  93                              const char *name)
  94 {
  95         if (unlikely(x6spi->magic != XFRM6_TUNNEL_SPI_MAGIC)) {
  96                 X6TPRINTK3(KERN_DEBUG "%s(): x6spi object "
  97                                       "at %p has corrupted magic %08x "
  98                                       "(should be %08x)\n",
  99                            name, x6spi, x6spi->magic, XFRM6_TUNNEL_SPI_MAGIC);
 100                 return -1;
 101         }
 102         return 0;
 103 }
 104 #else
 105 static int inline x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
 106                                     const char *name)
 107 {
 108         return 0;
 109 }
 110 #endif
 111
 112 #define X6SPI_CHECK_MAGIC(x6spi) x6spi_check_magic((x6spi), __FUNCTION__)
 113
 114
 115 static unsigned inline xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
 116 {
 117         unsigned h;
 118
 119         X6TPRINTK3(KERN_DEBUG "%s(addr=%p)\n", __FUNCTION__, addr);
 120
 121         h = addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3];
 122         h ^= h >> 16;
 123         h ^= h >> 8;
 124         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
 125
 126         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, h);
 127
 128         return h;
 129 }
 130
 131 static unsigned inline xfrm6_tunnel_spi_hash_byspi(u32 spi)
 132 {
 133         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
 134 }
 135
 136
 137 static int xfrm6_tunnel_spi_init(void)
 138 {
 139         int i;
 140
 141         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 142
 143         xfrm6_tunnel_spi = 0;
 144         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 145                                                   sizeof(struct xfrm6_tunnel_spi),
 146                                                   0, SLAB_HWCACHE_ALIGN,
 147                                                   NULL, NULL);
 148         if (!xfrm6_tunnel_spi_kmem) {
 149                 X6TPRINTK1(KERN_ERR
 150                            "%s(): failed to allocate xfrm6_tunnel_spi_kmem\n",
 151                            __FUNCTION__);
 152                 return -ENOMEM;
 153         }
 154
 155         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 156                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
 157         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 158                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
 159         return 0;
 160 }
 161
 162 static void xfrm6_tunnel_spi_fini(void)
 163 {
 164         int i;
 165
 166         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 167
 168         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
 169                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
 170                         goto err;
 171         }
 172         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
 173                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
 174                         goto err;
 175         }
 176         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 177         xfrm6_tunnel_spi_kmem = NULL;
 178         return;
 179 err:
 180         X6TPRINTK1(KERN_ERR "%s(): table is not empty\n", __FUNCTION__);
 181         return;
 182 }
 183
 184 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 185 {
 186         struct xfrm6_tunnel_spi *x6spi;
 187         struct hlist_node *pos;
 188
 189         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 190
 191         hlist_for_each_entry(x6spi, pos,
 192                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 193                              list_byaddr) {
 194                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 195                         X6SPI_CHECK_MAGIC(x6spi);
 196                         X6TPRINTK3(KERN_DEBUG "%s() = %p(%u)\n", __FUNCTION__, x6spi, x6spi->spi);
 197                         return x6spi;
 198                 }
 199         }
 200
 201         X6TPRINTK3(KERN_DEBUG "%s() = NULL(0)\n", __FUNCTION__);
 202         return NULL;
 203 }
 204
 205 u32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 206 {
 207         struct xfrm6_tunnel_spi *x6spi;
 208         u32 spi;
 209
 210         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 211
 212         read_lock_bh(&xfrm6_tunnel_spi_lock);
 213         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 214         spi = x6spi ? x6spi->spi : 0;
 215         read_unlock_bh(&xfrm6_tunnel_spi_lock);
 216         return spi;
 217 }
 218
 219 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 220
 221 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 222 {
 223         u32 spi;
 224         struct xfrm6_tunnel_spi *x6spi;
 225         struct hlist_node *pos;
 226         unsigned index;
 227
 228         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 229
 230         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
 231             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
 232                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
 233         else
 234                 xfrm6_tunnel_spi++;
 235
 236         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 237                 index = xfrm6_tunnel_spi_hash_byspi(spi);
 238                 hlist_for_each_entry(x6spi, pos,
 239                                      &xfrm6_tunnel_spi_byspi[index],
 240                                      list_byspi) {
 241                         if (x6spi->spi == spi)
 242                                 goto try_next_1;
 243                 }
 244                 xfrm6_tunnel_spi = spi;
 245                 goto alloc_spi;
 246 try_next_1:;
 247         }
 248         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
 249                 index = xfrm6_tunnel_spi_hash_byspi(spi);
 250                 hlist_for_each_entry(x6spi, pos,
 251                                      &xfrm6_tunnel_spi_byspi[index],
 252                                      list_byspi) {
 253                         if (x6spi->spi == spi)
 254                                 goto try_next_2;
 255                 }
 256                 xfrm6_tunnel_spi = spi;
 257                 goto alloc_spi;
 258 try_next_2:;
 259         }
 260         spi = 0;
 261         goto out;
 262 alloc_spi:
 263         X6TPRINTK3(KERN_DEBUG "%s(): allocate new spi for " NIP6_FMT "\n",
 264                               __FUNCTION__,
 265                               NIP6(*(struct in6_addr *)saddr));
 266         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, SLAB_ATOMIC);
 267         if (!x6spi) {
 268                 X6TPRINTK1(KERN_ERR "%s(): kmem_cache_alloc() failed\n",
 269                            __FUNCTION__);
 270                 goto out;
 271         }
 272 #ifdef XFRM6_TUNNEL_SPI_MAGIC
 273         x6spi->magic = XFRM6_TUNNEL_SPI_MAGIC;
 274 #endif
 275         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 276         x6spi->spi = spi;
 277         atomic_set(&x6spi->refcnt, 1);
 278
 279         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
 280
 281         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 282         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
 283         X6SPI_CHECK_MAGIC(x6spi);
 284 out:
 285         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
 286         return spi;
 287 }
 288
 289 u32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 290 {
 291         struct xfrm6_tunnel_spi *x6spi;
 292         u32 spi;
 293
 294         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 295
 296         write_lock_bh(&xfrm6_tunnel_spi_lock);
 297         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 298         if (x6spi) {
 299                 atomic_inc(&x6spi->refcnt);
 300                 spi = x6spi->spi;
 301         } else
 302                 spi = __xfrm6_tunnel_alloc_spi(saddr);
 303         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 304
 305         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
 306
 307         return spi;
 308 }
 309
 310 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 311
 312 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
 313 {
 314         struct xfrm6_tunnel_spi *x6spi;
 315         struct hlist_node *pos, *n;
 316
 317         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 318
 319         write_lock_bh(&xfrm6_tunnel_spi_lock);
 320
 321         hlist_for_each_entry_safe(x6spi, pos, n,
 322                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 323                                   list_byaddr)
 324         {
 325                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 326                         X6TPRINTK3(KERN_DEBUG "%s(): x6spi object for " NIP6_FMT
 327                                               " found at %p\n",
 328                                    __FUNCTION__,
 329                                    NIP6(*(struct in6_addr *)saddr),
 330                                    x6spi);
 331                         X6SPI_CHECK_MAGIC(x6spi);
 332                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 333                                 hlist_del(&x6spi->list_byaddr);
 334                                 hlist_del(&x6spi->list_byspi);
 335                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
 336                                 break;
 337                         }
 338                 }
 339         }
 340         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 341 }
 342
 343 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 344
 345 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 346 {
 347         struct ipv6hdr *top_iph;
 348
 349         top_iph = (struct ipv6hdr *)skb->data;
 350         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 351
 352         return 0;
 353 }
 354
 355 static int xfrm6_tunnel_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
 356 {
 357         return 0;
 358 }
 359
 360 static struct xfrm6_tunnel *xfrm6_tunnel_handler;
 361 static DEFINE_MUTEX(xfrm6_tunnel_mutex);
 362
 363 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler)
 364 {
 365         int ret;
 366
 367         mutex_lock(&xfrm6_tunnel_mutex);
 368         ret = 0;
 369         if (xfrm6_tunnel_handler != NULL)
 370                 ret = -EINVAL;
 371         if (!ret)
 372                 xfrm6_tunnel_handler = handler;
 373         mutex_unlock(&xfrm6_tunnel_mutex);
 374
 375         return ret;
 376 }
 377
 378 EXPORT_SYMBOL(xfrm6_tunnel_register);
 379
 380 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler)
 381 {
 382         int ret;
 383
 384         mutex_lock(&xfrm6_tunnel_mutex);
 385         ret = 0;
 386         if (xfrm6_tunnel_handler != handler)
 387                 ret = -EINVAL;
 388         if (!ret)
 389                 xfrm6_tunnel_handler = NULL;
 390         mutex_unlock(&xfrm6_tunnel_mutex);
 391
 392         synchronize_net();
 393
 394         return ret;
 395 }
 396
 397 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
 398
 399 static int xfrm6_tunnel_rcv(struct sk_buff **pskb)
 400 {
 401         struct sk_buff *skb = *pskb;
 402         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
 403         struct ipv6hdr *iph = skb->nh.ipv6h;
 404         u32 spi;
 405
 406         /* device-like_ip6ip6_handler() */
 407         if (handler && handler->handler(pskb) == 0)
 408                 return 0;
 409
 410         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 411         return xfrm6_rcv_spi(pskb, spi);
 412 }
 413
 414 static void xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 415                              int type, int code, int offset, __u32 info)
 416 {
 417         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
 418
 419         /* call here first for device-like ip6ip6 err handling */
 420         if (handler) {
 421                 handler->err_handler(skb, opt, type, code, offset, info);
 422                 return;
 423         }
 424
 425         /* xfrm6_tunnel native err handling */
 426         switch (type) {
 427         case ICMPV6_DEST_UNREACH:
 428                 switch (code) {
 429                 case ICMPV6_NOROUTE:
 430                 case ICMPV6_ADM_PROHIBITED:
 431                 case ICMPV6_NOT_NEIGHBOUR:
 432                 case ICMPV6_ADDR_UNREACH:
 433                 case ICMPV6_PORT_UNREACH:
 434                 default:
 435                         X6TPRINTK3(KERN_DEBUG
 436                                    "xfrm6_tunnel: Destination Unreach.\n");
 437                         break;
 438                 }
 439                 break;
 440         case ICMPV6_PKT_TOOBIG:
 441                         X6TPRINTK3(KERN_DEBUG
 442                                    "xfrm6_tunnel: Packet Too Big.\n");
 443                 break;
 444         case ICMPV6_TIME_EXCEED:
 445                 switch (code) {
 446                 case ICMPV6_EXC_HOPLIMIT:
 447                         X6TPRINTK3(KERN_DEBUG
 448                                    "xfrm6_tunnel: Too small Hoplimit.\n");
 449                         break;
 450                 case ICMPV6_EXC_FRAGTIME:
 451                 default:
 452                         break;
 453                 }
 454                 break;
 455         case ICMPV6_PARAMPROB:
 456                 switch (code) {
 457                 case ICMPV6_HDR_FIELD: break;
 458                 case ICMPV6_UNK_NEXTHDR: break;
 459                 case ICMPV6_UNK_OPTION: break;
 460                 }
 461                 break;
 462         default:
 463                 break;
 464         }
 465         return;
 466 }
 467
 468 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 469 {
 470         if (!x->props.mode)
 471                 return -EINVAL;
 472
 473         if (x->encap)
 474                 return -EINVAL;
 475
 476         x->props.header_len = sizeof(struct ipv6hdr);
 477
 478         return 0;
 479 }
 480
 481 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 482 {
 483         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 484 }
 485
 486 static struct xfrm_type xfrm6_tunnel_type = {
 487         .description    = "IP6IP6",
 488         .owner          = THIS_MODULE,
 489         .proto          = IPPROTO_IPV6,
 490         .init_state     = xfrm6_tunnel_init_state,
 491         .destructor     = xfrm6_tunnel_destroy,
 492         .input          = xfrm6_tunnel_input,
 493         .output         = xfrm6_tunnel_output,
 494 };
 495
 496 static struct inet6_protocol xfrm6_tunnel_protocol = {
 497         .handler        = xfrm6_tunnel_rcv,
 498         .err_handler    = xfrm6_tunnel_err,
 499         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 500 };
 501
 502 static int __init xfrm6_tunnel_init(void)
 503 {
 504         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 505
 506         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
 507                 X6TPRINTK1(KERN_ERR
 508                            "xfrm6_tunnel init: can't add xfrm type\n");
 509                 return -EAGAIN;
 510         }
 511         if (inet6_add_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0) {
 512                 X6TPRINTK1(KERN_ERR
 513                            "xfrm6_tunnel init(): can't add protocol\n");
 514                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 515                 return -EAGAIN;
 516         }
 517         if (xfrm6_tunnel_spi_init() < 0) {
 518                 X6TPRINTK1(KERN_ERR
 519                            "xfrm6_tunnel init: failed to initialize spi\n");
 520                 inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6);
 521                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 522                 return -EAGAIN;
 523         }
 524         return 0;
 525 }
 526
 527 static void __exit xfrm6_tunnel_fini(void)
 528 {
 529         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 530
 531         xfrm6_tunnel_spi_fini();
 532         if (inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0)
 533                 X6TPRINTK1(KERN_ERR
 534                            "xfrm6_tunnel close: can't remove protocol\n");
 535         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 536                 X6TPRINTK1(KERN_ERR
 537                            "xfrm6_tunnel close: can't remove xfrm type\n");
 538 }
 539
 540 module_init(xfrm6_tunnel_init);
 541 module_exit(xfrm6_tunnel_fini);
 542 MODULE_LICENSE("GPL");