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 "
 263                               "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\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 "
 327                                               "for %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x "
 328                                               "found at %p\n",
 329                                    __FUNCTION__,
 330                                    NIP6(*(struct in6_addr *)saddr),
 331                                    x6spi);
 332                         X6SPI_CHECK_MAGIC(x6spi);
 333                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 334                                 hlist_del(&x6spi->list_byaddr);
 335                                 hlist_del(&x6spi->list_byspi);
 336                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
 337                                 break;
 338                         }
 339                 }
 340         }
 341         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 342 }
 343
 344 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 345
 346 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 347 {
 348         struct ipv6hdr *top_iph;
 349
 350         top_iph = (struct ipv6hdr *)skb->data;
 351         top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 352
 353         return 0;
 354 }
 355
 356 static int xfrm6_tunnel_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
 357 {
 358         return 0;
 359 }
 360
 361 static struct xfrm6_tunnel *xfrm6_tunnel_handler;
 362 static DECLARE_MUTEX(xfrm6_tunnel_sem);
 363
 364 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler)
 365 {
 366         int ret;
 367
 368         down(&xfrm6_tunnel_sem);
 369         ret = 0;
 370         if (xfrm6_tunnel_handler != NULL)
 371                 ret = -EINVAL;
 372         if (!ret)
 373                 xfrm6_tunnel_handler = handler;
 374         up(&xfrm6_tunnel_sem);
 375
 376         return ret;
 377 }
 378
 379 EXPORT_SYMBOL(xfrm6_tunnel_register);
 380
 381 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler)
 382 {
 383         int ret;
 384
 385         down(&xfrm6_tunnel_sem);
 386         ret = 0;
 387         if (xfrm6_tunnel_handler != handler)
 388                 ret = -EINVAL;
 389         if (!ret)
 390                 xfrm6_tunnel_handler = NULL;
 391         up(&xfrm6_tunnel_sem);
 392
 393         synchronize_net();
 394
 395         return ret;
 396 }
 397
 398 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
 399
 400 static int xfrm6_tunnel_rcv(struct sk_buff **pskb, unsigned int *nhoffp)
 401 {
 402         struct sk_buff *skb = *pskb;
 403         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
 404         struct ipv6hdr *iph = skb->nh.ipv6h;
 405         u32 spi;
 406
 407         /* device-like_ip6ip6_handler() */
 408         if (handler && handler->handler(pskb, nhoffp) == 0)
 409                 return 0;
 410
 411         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 412         return xfrm6_rcv_spi(pskb, nhoffp, spi);
 413 }
 414
 415 static void xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 416                              int type, int code, int offset, __u32 info)
 417 {
 418         struct xfrm6_tunnel *handler = xfrm6_tunnel_handler;
 419
 420         /* call here first for device-like ip6ip6 err handling */
 421         if (handler) {
 422                 handler->err_handler(skb, opt, type, code, offset, info);
 423                 return;
 424         }
 425
 426         /* xfrm6_tunnel native err handling */
 427         switch (type) {
 428         case ICMPV6_DEST_UNREACH:
 429                 switch (code) {
 430                 case ICMPV6_NOROUTE:
 431                 case ICMPV6_ADM_PROHIBITED:
 432                 case ICMPV6_NOT_NEIGHBOUR:
 433                 case ICMPV6_ADDR_UNREACH:
 434                 case ICMPV6_PORT_UNREACH:
 435                 default:
 436                         X6TPRINTK3(KERN_DEBUG
 437                                    "xfrm6_tunnel: Destination Unreach.\n");
 438                         break;
 439                 }
 440                 break;
 441         case ICMPV6_PKT_TOOBIG:
 442                         X6TPRINTK3(KERN_DEBUG
 443                                    "xfrm6_tunnel: Packet Too Big.\n");
 444                 break;
 445         case ICMPV6_TIME_EXCEED:
 446                 switch (code) {
 447                 case ICMPV6_EXC_HOPLIMIT:
 448                         X6TPRINTK3(KERN_DEBUG
 449                                    "xfrm6_tunnel: Too small Hoplimit.\n");
 450                         break;
 451                 case ICMPV6_EXC_FRAGTIME:
 452                 default:
 453                         break;
 454                 }
 455                 break;
 456         case ICMPV6_PARAMPROB:
 457                 switch (code) {
 458                 case ICMPV6_HDR_FIELD: break;
 459                 case ICMPV6_UNK_NEXTHDR: break;
 460                 case ICMPV6_UNK_OPTION: break;
 461                 }
 462                 break;
 463         default:
 464                 break;
 465         }
 466         return;
 467 }
 468
 469 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 470 {
 471         if (!x->props.mode)
 472                 return -EINVAL;
 473
 474         if (x->encap)
 475                 return -EINVAL;
 476
 477         x->props.header_len = sizeof(struct ipv6hdr);
 478
 479         return 0;
 480 }
 481
 482 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 483 {
 484         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 485 }
 486
 487 static struct xfrm_type xfrm6_tunnel_type = {
 488         .description    = "IP6IP6",
 489         .owner          = THIS_MODULE,
 490         .proto          = IPPROTO_IPV6,
 491         .init_state     = xfrm6_tunnel_init_state,
 492         .destructor     = xfrm6_tunnel_destroy,
 493         .input          = xfrm6_tunnel_input,
 494         .output         = xfrm6_tunnel_output,
 495 };
 496
 497 static struct inet6_protocol xfrm6_tunnel_protocol = {
 498         .handler        = xfrm6_tunnel_rcv,
 499         .err_handler    = xfrm6_tunnel_err,
 500         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 501 };
 502
 503 static int __init xfrm6_tunnel_init(void)
 504 {
 505         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 506
 507         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
 508                 X6TPRINTK1(KERN_ERR
 509                            "xfrm6_tunnel init: can't add xfrm type\n");
 510                 return -EAGAIN;
 511         }
 512         if (inet6_add_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0) {
 513                 X6TPRINTK1(KERN_ERR
 514                            "xfrm6_tunnel init(): can't add protocol\n");
 515                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 516                 return -EAGAIN;
 517         }
 518         if (xfrm6_tunnel_spi_init() < 0) {
 519                 X6TPRINTK1(KERN_ERR
 520                            "xfrm6_tunnel init: failed to initialize spi\n");
 521                 inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6);
 522                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 523                 return -EAGAIN;
 524         }
 525         return 0;
 526 }
 527
 528 static void __exit xfrm6_tunnel_fini(void)
 529 {
 530         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 531
 532         xfrm6_tunnel_spi_fini();
 533         if (inet6_del_protocol(&xfrm6_tunnel_protocol, IPPROTO_IPV6) < 0)
 534                 X6TPRINTK1(KERN_ERR
 535                            "xfrm6_tunnel close: can't remove protocol\n");
 536         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 537                 X6TPRINTK1(KERN_ERR
 538                            "xfrm6_tunnel close: can't remove xfrm type\n");
 539 }
 540
 541 module_init(xfrm6_tunnel_init);
 542 module_exit(xfrm6_tunnel_fini);
 543 MODULE_LICENSE("GPL");