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 <linux/ipv6.h>
  32 #include <linux/icmpv6.h>
  33 #include <linux/mutex.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 sk_buff *skb)
 355 {
 356         return 0;
 357 }
 358
 359 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 360 {
 361         struct ipv6hdr *iph = skb->nh.ipv6h;
 362         u32 spi;
 363
 364         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 365         return xfrm6_rcv_spi(skb, spi);
 366 }
 367
 368 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 369                             int type, int code, int offset, __u32 info)
 370 {
 371         /* xfrm6_tunnel native err handling */
 372         switch (type) {
 373         case ICMPV6_DEST_UNREACH:
 374                 switch (code) {
 375                 case ICMPV6_NOROUTE:
 376                 case ICMPV6_ADM_PROHIBITED:
 377                 case ICMPV6_NOT_NEIGHBOUR:
 378                 case ICMPV6_ADDR_UNREACH:
 379                 case ICMPV6_PORT_UNREACH:
 380                 default:
 381                         X6TPRINTK3(KERN_DEBUG
 382                                    "xfrm6_tunnel: Destination Unreach.\n");
 383                         break;
 384                 }
 385                 break;
 386         case ICMPV6_PKT_TOOBIG:
 387                         X6TPRINTK3(KERN_DEBUG
 388                                    "xfrm6_tunnel: Packet Too Big.\n");
 389                 break;
 390         case ICMPV6_TIME_EXCEED:
 391                 switch (code) {
 392                 case ICMPV6_EXC_HOPLIMIT:
 393                         X6TPRINTK3(KERN_DEBUG
 394                                    "xfrm6_tunnel: Too small Hoplimit.\n");
 395                         break;
 396                 case ICMPV6_EXC_FRAGTIME:
 397                 default:
 398                         break;
 399                 }
 400                 break;
 401         case ICMPV6_PARAMPROB:
 402                 switch (code) {
 403                 case ICMPV6_HDR_FIELD: break;
 404                 case ICMPV6_UNK_NEXTHDR: break;
 405                 case ICMPV6_UNK_OPTION: break;
 406                 }
 407                 break;
 408         default:
 409                 break;
 410         }
 411
 412         return 0;
 413 }
 414
 415 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 416 {
 417         if (!x->props.mode)
 418                 return -EINVAL;
 419
 420         if (x->encap)
 421                 return -EINVAL;
 422
 423         x->props.header_len = sizeof(struct ipv6hdr);
 424
 425         return 0;
 426 }
 427
 428 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 429 {
 430         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 431 }
 432
 433 static struct xfrm_type xfrm6_tunnel_type = {
 434         .description    = "IP6IP6",
 435         .owner          = THIS_MODULE,
 436         .proto          = IPPROTO_IPV6,
 437         .init_state     = xfrm6_tunnel_init_state,
 438         .destructor     = xfrm6_tunnel_destroy,
 439         .input          = xfrm6_tunnel_input,
 440         .output         = xfrm6_tunnel_output,
 441 };
 442
 443 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
 444         .handler        = xfrm6_tunnel_rcv,
 445         .err_handler    = xfrm6_tunnel_err,
 446         .priority       = 2,
 447 };
 448
 449 static int __init xfrm6_tunnel_init(void)
 450 {
 451         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 452
 453         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0) {
 454                 X6TPRINTK1(KERN_ERR
 455                            "xfrm6_tunnel init: can't add xfrm type\n");
 456                 return -EAGAIN;
 457         }
 458         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler)) {
 459                 X6TPRINTK1(KERN_ERR
 460                            "xfrm6_tunnel init(): can't add handler\n");
 461                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 462                 return -EAGAIN;
 463         }
 464         if (xfrm6_tunnel_spi_init() < 0) {
 465                 X6TPRINTK1(KERN_ERR
 466                            "xfrm6_tunnel init: failed to initialize spi\n");
 467                 xfrm6_tunnel_deregister(&xfrm6_tunnel_handler);
 468                 xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 469                 return -EAGAIN;
 470         }
 471         return 0;
 472 }
 473
 474 static void __exit xfrm6_tunnel_fini(void)
 475 {
 476         X6TPRINTK3(KERN_DEBUG "%s()\n", __FUNCTION__);
 477
 478         xfrm6_tunnel_spi_fini();
 479         if (xfrm6_tunnel_deregister(&xfrm6_tunnel_handler))
 480                 X6TPRINTK1(KERN_ERR
 481                            "xfrm6_tunnel close: can't remove handler\n");
 482         if (xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 483                 X6TPRINTK1(KERN_ERR
 484                            "xfrm6_tunnel close: can't remove xfrm type\n");
 485 }
 486
 487 module_init(xfrm6_tunnel_init);
 488 module_exit(xfrm6_tunnel_fini);
 489 MODULE_LICENSE("GPL");