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/module.h>
  25 #include <linux/xfrm.h>
  26 #include <linux/list.h>
  27 #include <net/ip.h>
  28 #include <net/xfrm.h>
  29 #include <net/ipv6.h>
  30 #include <linux/ipv6.h>
  31 #include <linux/icmpv6.h>
  32 #include <linux/mutex.h>
  33
  34 /*
  35  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  36  * per xfrm_address_t.
  37  */
  38 struct xfrm6_tunnel_spi {
  39         struct hlist_node list_byaddr;
  40         struct hlist_node list_byspi;
  41         xfrm_address_t addr;
  42         u32 spi;
  43         atomic_t refcnt;
  44 };
  45
  46 static DEFINE_RWLOCK(xfrm6_tunnel_spi_lock);
  47
  48 static u32 xfrm6_tunnel_spi;
  49
  50 #define XFRM6_TUNNEL_SPI_MIN    1
  51 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  52
  53 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
  54
  55 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  56 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  57
  58 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  59 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  60
  61 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
  62 {
  63         unsigned h;
  64
  65         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
  66         h ^= h >> 16;
  67         h ^= h >> 8;
  68         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
  69
  70         return h;
  71 }
  72
  73 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
  74 {
  75         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
  76 }
  77
  78
  79 static int xfrm6_tunnel_spi_init(void)
  80 {
  81         int i;
  82
  83         xfrm6_tunnel_spi = 0;
  84         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
  85                                                   sizeof(struct xfrm6_tunnel_spi),
  86                                                   0, SLAB_HWCACHE_ALIGN,
  87                                                   NULL);
  88         if (!xfrm6_tunnel_spi_kmem)
  89                 return -ENOMEM;
  90
  91         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
  92                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
  93         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
  94                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
  95         return 0;
  96 }
  97
  98 static void xfrm6_tunnel_spi_fini(void)
  99 {
 100         int i;
 101
 102         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
 103                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
 104                         return;
 105         }
 106         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
 107                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
 108                         return;
 109         }
 110         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 111         xfrm6_tunnel_spi_kmem = NULL;
 112 }
 113
 114 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 115 {
 116         struct xfrm6_tunnel_spi *x6spi;
 117         struct hlist_node *pos;
 118
 119         hlist_for_each_entry(x6spi, pos,
 120                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 121                              list_byaddr) {
 122                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
 123                         return x6spi;
 124         }
 125
 126         return NULL;
 127 }
 128
 129 __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 130 {
 131         struct xfrm6_tunnel_spi *x6spi;
 132         u32 spi;
 133
 134         read_lock_bh(&xfrm6_tunnel_spi_lock);
 135         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 136         spi = x6spi ? x6spi->spi : 0;
 137         read_unlock_bh(&xfrm6_tunnel_spi_lock);
 138         return htonl(spi);
 139 }
 140
 141 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 142
 143 static int __xfrm6_tunnel_spi_check(u32 spi)
 144 {
 145         struct xfrm6_tunnel_spi *x6spi;
 146         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 147         struct hlist_node *pos;
 148
 149         hlist_for_each_entry(x6spi, pos,
 150                              &xfrm6_tunnel_spi_byspi[index],
 151                              list_byspi) {
 152                 if (x6spi->spi == spi)
 153                         return -1;
 154         }
 155         return index;
 156 }
 157
 158 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 159 {
 160         u32 spi;
 161         struct xfrm6_tunnel_spi *x6spi;
 162         int index;
 163
 164         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
 165             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
 166                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
 167         else
 168                 xfrm6_tunnel_spi++;
 169
 170         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 171                 index = __xfrm6_tunnel_spi_check(spi);
 172                 if (index >= 0)
 173                         goto alloc_spi;
 174         }
 175         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
 176                 index = __xfrm6_tunnel_spi_check(spi);
 177                 if (index >= 0)
 178                         goto alloc_spi;
 179         }
 180         spi = 0;
 181         goto out;
 182 alloc_spi:
 183         xfrm6_tunnel_spi = spi;
 184         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 185         if (!x6spi)
 186                 goto out;
 187
 188         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 189         x6spi->spi = spi;
 190         atomic_set(&x6spi->refcnt, 1);
 191
 192         hlist_add_head(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
 193
 194         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 195         hlist_add_head(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
 196 out:
 197         return spi;
 198 }
 199
 200 __be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 201 {
 202         struct xfrm6_tunnel_spi *x6spi;
 203         u32 spi;
 204
 205         write_lock_bh(&xfrm6_tunnel_spi_lock);
 206         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 207         if (x6spi) {
 208                 atomic_inc(&x6spi->refcnt);
 209                 spi = x6spi->spi;
 210         } else
 211                 spi = __xfrm6_tunnel_alloc_spi(saddr);
 212         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 213
 214         return htonl(spi);
 215 }
 216
 217 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 218
 219 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
 220 {
 221         struct xfrm6_tunnel_spi *x6spi;
 222         struct hlist_node *pos, *n;
 223
 224         write_lock_bh(&xfrm6_tunnel_spi_lock);
 225
 226         hlist_for_each_entry_safe(x6spi, pos, n,
 227                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 228                                   list_byaddr)
 229         {
 230                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 231                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 232                                 hlist_del(&x6spi->list_byaddr);
 233                                 hlist_del(&x6spi->list_byspi);
 234                                 kmem_cache_free(xfrm6_tunnel_spi_kmem, x6spi);
 235                                 break;
 236                         }
 237                 }
 238         }
 239         write_unlock_bh(&xfrm6_tunnel_spi_lock);
 240 }
 241
 242 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 243
 244 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 245 {
 246         skb_push(skb, -skb_network_offset(skb));
 247         return 0;
 248 }
 249
 250 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 251 {
 252         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 253 }
 254
 255 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 256 {
 257         struct ipv6hdr *iph = ipv6_hdr(skb);
 258         __be32 spi;
 259
 260         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 261         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
 262 }
 263
 264 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 265                             int type, int code, int offset, __be32 info)
 266 {
 267         /* xfrm6_tunnel native err handling */
 268         switch (type) {
 269         case ICMPV6_DEST_UNREACH:
 270                 switch (code) {
 271                 case ICMPV6_NOROUTE:
 272                 case ICMPV6_ADM_PROHIBITED:
 273                 case ICMPV6_NOT_NEIGHBOUR:
 274                 case ICMPV6_ADDR_UNREACH:
 275                 case ICMPV6_PORT_UNREACH:
 276                 default:
 277                         break;
 278                 }
 279                 break;
 280         case ICMPV6_PKT_TOOBIG:
 281                 break;
 282         case ICMPV6_TIME_EXCEED:
 283                 switch (code) {
 284                 case ICMPV6_EXC_HOPLIMIT:
 285                         break;
 286                 case ICMPV6_EXC_FRAGTIME:
 287                 default:
 288                         break;
 289                 }
 290                 break;
 291         case ICMPV6_PARAMPROB:
 292                 switch (code) {
 293                 case ICMPV6_HDR_FIELD: break;
 294                 case ICMPV6_UNK_NEXTHDR: break;
 295                 case ICMPV6_UNK_OPTION: break;
 296                 }
 297                 break;
 298         default:
 299                 break;
 300         }
 301
 302         return 0;
 303 }
 304
 305 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 306 {
 307         if (x->props.mode != XFRM_MODE_TUNNEL)
 308                 return -EINVAL;
 309
 310         if (x->encap)
 311                 return -EINVAL;
 312
 313         x->props.header_len = sizeof(struct ipv6hdr);
 314
 315         return 0;
 316 }
 317
 318 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 319 {
 320         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 321 }
 322
 323 static const struct xfrm_type xfrm6_tunnel_type = {
 324         .description    = "IP6IP6",
 325         .owner          = THIS_MODULE,
 326         .proto          = IPPROTO_IPV6,
 327         .init_state     = xfrm6_tunnel_init_state,
 328         .destructor     = xfrm6_tunnel_destroy,
 329         .input          = xfrm6_tunnel_input,
 330         .output         = xfrm6_tunnel_output,
 331 };
 332
 333 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
 334         .handler        = xfrm6_tunnel_rcv,
 335         .err_handler    = xfrm6_tunnel_err,
 336         .priority       = 2,
 337 };
 338
 339 static struct xfrm6_tunnel xfrm46_tunnel_handler = {
 340         .handler        = xfrm6_tunnel_rcv,
 341         .err_handler    = xfrm6_tunnel_err,
 342         .priority       = 2,
 343 };
 344
 345 static int __init xfrm6_tunnel_init(void)
 346 {
 347         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 348                 goto err;
 349         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6))
 350                 goto unreg;
 351         if (xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET))
 352                 goto dereg6;
 353         if (xfrm6_tunnel_spi_init() < 0)
 354                 goto dereg46;
 355         return 0;
 356
 357 dereg46:
 358         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 359 dereg6:
 360         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 361 unreg:
 362         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 363 err:
 364         return -EAGAIN;
 365 }
 366
 367 static void __exit xfrm6_tunnel_fini(void)
 368 {
 369         xfrm6_tunnel_spi_fini();
 370         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 371         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 372         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 373 }
 374
 375 module_init(xfrm6_tunnel_init);
 376 module_exit(xfrm6_tunnel_fini);
 377 MODULE_LICENSE("GPL");
 378 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);