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
  35 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
  36 # define X6TDEBUG       3
  37 #else
  38 # define X6TDEBUG       1
  39 #endif
  40
  41 #define X6TPRINTK(fmt, args...)         printk(fmt, ## args)
  42 #define X6TNOPRINTK(fmt, args...)       do { ; } while(0)
  43
  44 #if X6TDEBUG >= 1
  45 # define X6TPRINTK1     X6TPRINTK
  46 #else
  47 # define X6TPRINTK1     X6TNOPRINTK
  48 #endif
  49
  50 #if X6TDEBUG >= 3
  51 # define X6TPRINTK3     X6TPRINTK
  52 #else
  53 # define X6TPRINTK3     X6TNOPRINTK
  54 #endif
  55
  56 /*
  57  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  58  * per xfrm_address_t.
  59  */
  60 struct xfrm6_tunnel_spi {
  61         struct hlist_node list_byaddr;
  62         struct hlist_node list_byspi;
  63         xfrm_address_t addr;
  64         u32 spi;
  65         atomic_t refcnt;
  66 #ifdef XFRM6_TUNNEL_SPI_MAGIC
  67         u32 magic;
  68 #endif
  69 };
  70
  71 #ifdef CONFIG_IPV6_XFRM6_TUNNEL_DEBUG
  72 # define XFRM6_TUNNEL_SPI_MAGIC 0xdeadbeef
  73 #endif
  74
  75 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
  76
  77 static u32 xfrm6_tunnel_spi;
  78
  79 #define XFRM6_TUNNEL_SPI_MIN    1
  80 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  81
  82 static kmem_cache_t *xfrm6_tunnel_spi_kmem __read_mostly;
  83
  84 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  85 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  86
  87 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  88 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  89
  90 #ifdef XFRM6_TUNNEL_SPI_MAGIC
  91 static int x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
  92                              const char *name)
  93 {
  94         if (unlikely(x6spi->magic != XFRM6_TUNNEL_SPI_MAGIC)) {
  95                 X6TPRINTK3(KERN_DEBUG "%s(): x6spi object "
  96                                       "at %p has corrupted magic %08x "
  97                                       "(should be %08x)\n",
  98                            name, x6spi, x6spi->magic, XFRM6_TUNNEL_SPI_MAGIC);
  99                 return -1;
 100         }
 101         return 0;
 102 }
 103 #else
 104 static int inline x6spi_check_magic(const struct xfrm6_tunnel_spi *x6spi,
 105                                     const char *name)
 106 {
 107         return 0;
 108 }
 109 #endif
 110
 111 #define X6SPI_CHECK_MAGIC(x6spi) x6spi_check_magic((x6spi), __FUNCTION__)
 112
 113
 114 static unsigned inline xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
 115 {
 116         unsigned h;
 117
 118         X6TPRINTK3(KERN_DEBUG "%s(addr=%p)\n", __FUNCTION__, addr);
 119
 120         h = addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3];
 121         h ^= h >> 16;
 122         h ^= h >> 8;
 123         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
 124
 125         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, h);
 126
 127         return h;
 128 }
 129
 130 static unsigned inline xfrm6_tunnel_spi_hash_byspi(u32 spi)
 131 {
 132         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
 133 }
 134
 135
 136 static int xfrm6_tunnel_spi_init(void)
 137 {
 138         int i;
 139
 140         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 141
 142         xfrm6_tunnel_spi = 0;
 143         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 144                                                   sizeof(struct xfrm6_tunnel_spi),
 145                                                   0, SLAB_HWCACHE_ALIGN,
 146                                                   NULL, NULL);
 147         if (!xfrm6_tunnel_spi_kmem) {
 148                 X6TPRINTK1(KERN_ERR
 149                            "%s(): failed to allocate xfrm6_tunnel_spi_kmem\n",
 150                            __FUNCTION__);
 151                 return -ENOMEM;
 152         }
 153
 154         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 155                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
 156         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 157                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
 158         return 0;
 159 }
 160
 161 static void xfrm6_tunnel_spi_fini(void)
 162 {
 163         int i;
 164
 165         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 166
 167         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
 168                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
 169                         goto err;
 170         }
 171         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
 172                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
 173                         goto err;
 174         }
 175         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 176         xfrm6_tunnel_spi_kmem = NULL;
 177         return;
 178 err:
 179         X6TPRINTK1(KERN_ERR "%s(): table is not empty\n", __FUNCTION__);
 180         return;
 181 }
 182
 183 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 184 {
 185         struct xfrm6_tunnel_spi *x6spi;
 186         struct hlist_node *pos;
 187
 188         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 189
 190         hlist_for_each_entry(x6spi, pos,
 191                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 192                              list_byaddr) {
 193                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 194                         X6SPI_CHECK_MAGIC(x6spi);
 195                         X6TPRINTK3(KERN_DEBUG "%s() = %p(%u)\n", __FUNCTION__, x6spi, x6spi->spi);
 196                         return x6spi;
 197                 }
 198         }
 199
 200         X6TPRINTK3(KERN_DEBUG "%s() = NULL(0)\n", __FUNCTION__);
 201         return NULL;
 202 }
 203
 204 u32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 205 {
 206         struct xfrm6_tunnel_spi *x6spi;
 207         u32 spi;
 208
 209         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 210
 211         read_lock_bh(&xfrm6_tunnel_spi_lock);
 212         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 213         spi = x6spi ? x6spi->spi : 0;
 214         read_unlock_bh(&xfrm6_tunnel_spi_lock);
 215         return spi;
 216 }
 217
 218 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 219
 220 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 221 {
 222         u32 spi;
 223         struct xfrm6_tunnel_spi *x6spi;
 224         struct hlist_node *pos;
 225         unsigned index;
 226
 227         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 228
 229         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
 230             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
 231                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
 232         else
 233                 xfrm6_tunnel_spi++;
 234
 235         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 236                 index = xfrm6_tunnel_spi_hash_byspi(spi);
 237                 hlist_for_each_entry(x6spi, pos,
 238                                      &xfrm6_tunnel_spi_byspi[index],
 239                                      list_byspi) {
 240                         if (x6spi->spi == spi)
 241                                 goto try_next_1;
 242                 }
 243                 xfrm6_tunnel_spi = spi;
 244                 goto alloc_spi;
 245 try_next_1:;
 246         }
 247         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
 248                 index = xfrm6_tunnel_spi_hash_byspi(spi);
 249                 hlist_for_each_entry(x6spi, pos,
 250                                      &xfrm6_tunnel_spi_byspi[index],
 251                                      list_byspi) {
 252                         if (x6spi->spi == spi)
 253                                 goto try_next_2;
 254                 }
 255                 xfrm6_tunnel_spi = spi;
 256                 goto alloc_spi;
 257 try_next_2:;
 258         }
 259         spi = 0;
 260         goto out;
 261 alloc_spi:
 262         X6TPRINTK3(KERN_DEBUG "%s(): allocate new spi for " NIP6_FMT "\n",
 263                               __FUNCTION__,
 264                               NIP6(*(struct in6_addr *)saddr));
 265         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, SLAB_ATOMIC);
 266         if (!x6spi) {
 267                 X6TPRINTK1(KERN_ERR "%s(): kmem_cache_alloc() failed\n",
 268                            __FUNCTION__);
 269                 goto out;
 270         }
 271 #ifdef XFRM6_TUNNEL_SPI_MAGIC
 272         x6spi->magic = XFRM6_TUNNEL_SPI_MAGIC;
 273 #endif
 274         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 275         x6spi->spi = spi;
 276         atomic_set(&x6spi->refcnt, 1);
 277
 278         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
 279
 280         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 281         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
 282         X6SPI_CHECK_MAGIC(x6spi);
 283 out:
 284         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
 285         return spi;
 286 }
 287
 288 u32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 289 {
 290         struct xfrm6_tunnel_spi *x6spi;
 291         u32 spi;
 292
 293         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 294
 295         write_lock_bh(&xfrm6_tunnel_spi_lock);
 296         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 297         if (x6spi) {
 298                 atomic_inc(&x6spi->refcnt);
 299                 spi = x6spi->spi;
 300         } else
 301                 spi = __xfrm6_tunnel_alloc_spi(saddr);
 302         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 303
 304         X6TPRINTK3(KERN_DEBUG "%s() = %u\n", __FUNCTION__, spi);
 305
 306         return spi;
 307 }
 308
 309 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 310
 311 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
 312 {
 313         struct xfrm6_tunnel_spi *x6spi;
 314         struct hlist_node *pos, *n;
 315
 316         X6TPRINTK3(KERN_DEBUG "%s(saddr=%p)\n", __FUNCTION__, saddr);
 317
 318         write_lock_bh(&xfrm6_tunnel_spi_lock);
 319
 320         hlist_for_each_entry_safe(x6spi, pos, n,
 321                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 322                                   list_byaddr)
 323         {
 324                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 325                         X6TPRINTK3(KERN_DEBUG "%s(): x6spi object for " NIP6_FMT
 326                                               " found at %p\n",
 327                                    __FUNCTION__,
 328                                    NIP6(*(struct in6_addr *)saddr),
 329                                    x6spi);
 330                         X6SPI_CHECK_MAGIC(x6spi);
 331                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 332                                 hlist_del(&x6spi->list_byaddr);
 333                                 hlist_del(&x6spi->list_byspi);
 334                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
 335                                 break;
 336                         }
 337                 }
 338         }
 339         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 340 }
 341
 342 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 343
 344 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 345 {
 346         struct ipv6hdr *top_iph;
 347
 348         top_iph = (struct ipv6hdr *)skb->data;
 349         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 350
 351         return 0;
 352 }
 353
 354 static int xfrm6_tunnel_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
 355 {
 356         return 0;
 357 }
 358
 359 static struct xfrm6_tunnel *xfrm6_tunnel_handler;
 360 static DECLARE_MUTEX(xfrm6_tunnel_sem);
 361
 362 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler)
 363 {
 364         int ret;
 365
 366         down(&xfrm6_tunnel_sem);
 367         ret = 0;
 368         if (xfrm6_tunnel_handler != NULL)
 369                 ret = -EINVAL;
 370         if (!ret)
 371                 xfrm6_tunnel_handler = handler;
 372         up(&xfrm6_tunnel_sem);
 373
 374         return ret;
 375 }
 376
 377 EXPORT_SYMBOL(xfrm6_tunnel_register);
 378
 379 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler)
 380 {
 381         int ret;
 382
 383         down(&xfrm6_tunnel_sem);
 384         ret = 0;
 385         if (xfrm6_tunnel_handler != handler)
 386                 ret = -EINVAL;
 387         if (!ret)
 388                 xfrm6_tunnel_handler = NULL;
 389         up(&xfrm6_tunnel_sem);
 390
 391         synchronize_net();
 392
 393         return ret;
 394 }
 395
 396 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
 397
 398 static int xfrm6_tunnel_rcv(struct sk_buff **pskb)
 399 {
 400         struct sk_buff *skb = *pskb;
 401         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
 402         struct ipv6hdr *iph = skb->nh.ipv6h;
 403         u32 spi;
 404
 405         /* device-like_ip6ip6_handler() */
 406         if (handler && handler->handler(pskb) == 0)
 407                 return 0;
 408
 409         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 410         return xfrm6_rcv_spi(pskb, spi) > 0 ? : 0;
 411 }
 412
 413 static void xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 414                              int type, int code, int offset, __u32 info)
 415 {
 416         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
 417
 418         /* call here first for device-like ip6ip6 err handling */
 419         if (handler) {
 420                 handler->err_handler(skb, opt, type, code, offset, info);
 421                 return;
 422         }
 423
 424         /* xfrm6_tunnel native err handling */
 425         switch (type) {
 426         case ICMPV6_DEST_UNREACH:
 427                 switch (code) {
 428                 case ICMPV6_NOROUTE:
 429                 case ICMPV6_ADM_PROHIBITED:
 430                 case ICMPV6_NOT_NEIGHBOUR:
 431                 case ICMPV6_ADDR_UNREACH:
 432                 case ICMPV6_PORT_UNREACH:
 433                 default:
 434                         X6TPRINTK3(KERN_DEBUG
 435                                    "xfrm6_tunnel: Destination Unreach.\n");
 436                         break;
 437                 }
 438                 break;
 439         case ICMPV6_PKT_TOOBIG:
 440                         X6TPRINTK3(KERN_DEBUG
 441                                    "xfrm6_tunnel: Packet Too Big.\n");
 442                 break;
 443         case ICMPV6_TIME_EXCEED:
 444                 switch (code) {
 445                 case ICMPV6_EXC_HOPLIMIT:
 446                         X6TPRINTK3(KERN_DEBUG
 447                                    "xfrm6_tunnel: Too small Hoplimit.\n");
 448                         break;
 449                 case ICMPV6_EXC_FRAGTIME:
 450                 default:
 451                         break;
 452                 }
 453                 break;
 454         case ICMPV6_PARAMPROB:
 455                 switch (code) {
 456                 case ICMPV6_HDR_FIELD: break;
 457                 case ICMPV6_UNK_NEXTHDR: break;
 458                 case ICMPV6_UNK_OPTION: break;
 459                 }
 460                 break;
 461         default:
 462                 break;
 463         }
 464         return;
 465 }
 466
 467 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 468 {
 469         if (!x->props.mode)
 470                 return -EINVAL;
 471
 472         if (x->encap)
 473                 return -EINVAL;
 474
 475         x->props.header_len = sizeof(struct ipv6hdr);
 476
 477         return 0;
 478 }
 479
 480 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 481 {
 482         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 483 }
 484
 485 static struct xfrm_type xfrm6_tunnel_type = {
 486         .description    = "IP6IP6",
 487         .owner          = THIS_MODULE,
 488         .proto          = IPPROTO_IPV6,
 489         .init_state     = xfrm6_tunnel_init_state,
 490         .destructor     = xfrm6_tunnel_destroy,
 491         .input          = xfrm6_tunnel_input,
 492         .output         = xfrm6_tunnel_output,
 493 };
 494
 495 static struct inet6_protocol xfrm6_tunnel_protocol = {
 496         .handler        = xfrm6_tunnel_rcv,
 497         .err_handler    = xfrm6_tunnel_err,
 498         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 499 };
 500
 501 static int __init xfrm6_tunnel_init(void)
 502 {
 503         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 504
 505         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
 506                 X6TPRINTK1(KERN_ERR
 507                            "xfrm6_tunnel init: can't add xfrm type\n");
 508                 return -EAGAIN;
 509         }
 510         if (inet6_add_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0) {
 511                 X6TPRINTK1(KERN_ERR
 512                            "xfrm6_tunnel init(): can't add protocol\n");
 513                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 514                 return -EAGAIN;
 515         }
 516         if (xfrm6_tunnel_spi_init() < 0) {
 517                 X6TPRINTK1(KERN_ERR
 518                            "xfrm6_tunnel init: failed to initialize spi\n");
 519                 inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6);
 520                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 521                 return -EAGAIN;
 522         }
 523         return 0;
 524 }
 525
 526 static void __exit xfrm6_tunnel_fini(void)
 527 {
 528         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 529
 530         xfrm6_tunnel_spi_fini();
 531         if (inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0)
 532                 X6TPRINTK1(KERN_ERR
 533                            "xfrm6_tunnel close: can't remove protocol\n");
 534         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 535                 X6TPRINTK1(KERN_ERR
 536                            "xfrm6_tunnel close: can't remove xfrm type\n");
 537 }
 538
 539 module_init(xfrm6_tunnel_init);
 540 module_exit(xfrm6_tunnel_fini);
 541 MODULE_LICENSE("GPL");