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/rculist.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         struct rcu_head         rcu_head;
  45 };
  46
  47 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
  48
  49 static u32 xfrm6_tunnel_spi;
  50
  51 #define XFRM6_TUNNEL_SPI_MIN    1
  52 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  53
  54 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
  55
  56 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  57 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  58
  59 static struct hlist_head xfrm6_tunnel_spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  60 static struct hlist_head xfrm6_tunnel_spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  61
  62 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
  63 {
  64         unsigned h;
  65
  66         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
  67         h ^= h >> 16;
  68         h ^= h >> 8;
  69         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
  70
  71         return h;
  72 }
  73
  74 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
  75 {
  76         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
  77 }
  78
  79
  80 static int xfrm6_tunnel_spi_init(void)
  81 {
  82         int i;
  83
  84         xfrm6_tunnel_spi = 0;
  85         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
  86                                                   sizeof(struct xfrm6_tunnel_spi),
  87                                                   0, SLAB_HWCACHE_ALIGN,
  88                                                   NULL);
  89         if (!xfrm6_tunnel_spi_kmem)
  90                 return -ENOMEM;
  91
  92         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
  93                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byaddr[i]);
  94         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
  95                 INIT_HLIST_HEAD(&xfrm6_tunnel_spi_byspi[i]);
  96         return 0;
  97 }
  98
  99 static void xfrm6_tunnel_spi_fini(void)
 100 {
 101         int i;
 102
 103         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++) {
 104                 if (!hlist_empty(&xfrm6_tunnel_spi_byaddr[i]))
 105                         return;
 106         }
 107         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++) {
 108                 if (!hlist_empty(&xfrm6_tunnel_spi_byspi[i]))
 109                         return;
 110         }
 111         rcu_barrier();
 112         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 113         xfrm6_tunnel_spi_kmem = NULL;
 114 }
 115
 116 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 117 {
 118         struct xfrm6_tunnel_spi *x6spi;
 119         struct hlist_node *pos;
 120
 121         hlist_for_each_entry_rcu(x6spi, pos,
 122                              &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 123                              list_byaddr) {
 124                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
 125                         return x6spi;
 126         }
 127
 128         return NULL;
 129 }
 130
 131 __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 132 {
 133         struct xfrm6_tunnel_spi *x6spi;
 134         u32 spi;
 135
 136         rcu_read_lock_bh();
 137         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 138         spi = x6spi ? x6spi->spi : 0;
 139         rcu_read_unlock_bh();
 140         return htonl(spi);
 141 }
 142
 143 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 144
 145 static int __xfrm6_tunnel_spi_check(u32 spi)
 146 {
 147         struct xfrm6_tunnel_spi *x6spi;
 148         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 149         struct hlist_node *pos;
 150
 151         hlist_for_each_entry(x6spi, pos,
 152                              &xfrm6_tunnel_spi_byspi[index],
 153                              list_byspi) {
 154                 if (x6spi->spi == spi)
 155                         return -1;
 156         }
 157         return index;
 158 }
 159
 160 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 161 {
 162         u32 spi;
 163         struct xfrm6_tunnel_spi *x6spi;
 164         int index;
 165
 166         if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
 167             xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
 168                 xfrm6_tunnel_spi = XFRM6_TUNNEL_SPI_MIN;
 169         else
 170                 xfrm6_tunnel_spi++;
 171
 172         for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 173                 index = __xfrm6_tunnel_spi_check(spi);
 174                 if (index >= 0)
 175                         goto alloc_spi;
 176         }
 177         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
 178                 index = __xfrm6_tunnel_spi_check(spi);
 179                 if (index >= 0)
 180                         goto alloc_spi;
 181         }
 182         spi = 0;
 183         goto out;
 184 alloc_spi:
 185         xfrm6_tunnel_spi = spi;
 186         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 187         if (!x6spi)
 188                 goto out;
 189
 190         INIT_RCU_HEAD(&x6spi->rcu_head);
 191         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 192         x6spi->spi = spi;
 193         atomic_set(&x6spi->refcnt, 1);
 194
 195         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tunnel_spi_byspi[index]);
 196
 197         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 198         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tunnel_spi_byaddr[index]);
 199 out:
 200         return spi;
 201 }
 202
 203 __be32 xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 204 {
 205         struct xfrm6_tunnel_spi *x6spi;
 206         u32 spi;
 207
 208         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 209         x6spi = __xfrm6_tunnel_spi_lookup(saddr);
 210         if (x6spi) {
 211                 atomic_inc(&x6spi->refcnt);
 212                 spi = x6spi->spi;
 213         } else
 214                 spi = __xfrm6_tunnel_alloc_spi(saddr);
 215         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 216
 217         return htonl(spi);
 218 }
 219
 220 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 221
 222 static void x6spi_destroy_rcu(struct rcu_head *head)
 223 {
 224         kmem_cache_free(xfrm6_tunnel_spi_kmem,
 225                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 226 }
 227
 228 void xfrm6_tunnel_free_spi(xfrm_address_t *saddr)
 229 {
 230         struct xfrm6_tunnel_spi *x6spi;
 231         struct hlist_node *pos, *n;
 232
 233         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 234
 235         hlist_for_each_entry_safe(x6spi, pos, n,
 236                                   &xfrm6_tunnel_spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 237                                   list_byaddr)
 238         {
 239                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 240                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 241                                 hlist_del_rcu(&x6spi->list_byaddr);
 242                                 hlist_del_rcu(&x6spi->list_byspi);
 243                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
 244                                 break;
 245                         }
 246                 }
 247         }
 248         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 249 }
 250
 251 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 252
 253 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 254 {
 255         skb_push(skb, -skb_network_offset(skb));
 256         return 0;
 257 }
 258
 259 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 260 {
 261         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 262 }
 263
 264 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 265 {
 266         struct ipv6hdr *iph = ipv6_hdr(skb);
 267         __be32 spi;
 268
 269         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&iph->saddr);
 270         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
 271 }
 272
 273 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 274                             u8 type, u8 code, int offset, __be32 info)
 275 {
 276         /* xfrm6_tunnel native err handling */
 277         switch (type) {
 278         case ICMPV6_DEST_UNREACH:
 279                 switch (code) {
 280                 case ICMPV6_NOROUTE:
 281                 case ICMPV6_ADM_PROHIBITED:
 282                 case ICMPV6_NOT_NEIGHBOUR:
 283                 case ICMPV6_ADDR_UNREACH:
 284                 case ICMPV6_PORT_UNREACH:
 285                 default:
 286                         break;
 287                 }
 288                 break;
 289         case ICMPV6_PKT_TOOBIG:
 290                 break;
 291         case ICMPV6_TIME_EXCEED:
 292                 switch (code) {
 293                 case ICMPV6_EXC_HOPLIMIT:
 294                         break;
 295                 case ICMPV6_EXC_FRAGTIME:
 296                 default:
 297                         break;
 298                 }
 299                 break;
 300         case ICMPV6_PARAMPROB:
 301                 switch (code) {
 302                 case ICMPV6_HDR_FIELD: break;
 303                 case ICMPV6_UNK_NEXTHDR: break;
 304                 case ICMPV6_UNK_OPTION: break;
 305                 }
 306                 break;
 307         default:
 308                 break;
 309         }
 310
 311         return 0;
 312 }
 313
 314 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 315 {
 316         if (x->props.mode != XFRM_MODE_TUNNEL)
 317                 return -EINVAL;
 318
 319         if (x->encap)
 320                 return -EINVAL;
 321
 322         x->props.header_len = sizeof(struct ipv6hdr);
 323
 324         return 0;
 325 }
 326
 327 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 328 {
 329         xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);
 330 }
 331
 332 static const struct xfrm_type xfrm6_tunnel_type = {
 333         .description    = "IP6IP6",
 334         .owner          = THIS_MODULE,
 335         .proto          = IPPROTO_IPV6,
 336         .init_state     = xfrm6_tunnel_init_state,
 337         .destructor     = xfrm6_tunnel_destroy,
 338         .input          = xfrm6_tunnel_input,
 339         .output         = xfrm6_tunnel_output,
 340 };
 341
 342 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
 343         .handler        = xfrm6_tunnel_rcv,
 344         .err_handler    = xfrm6_tunnel_err,
 345         .priority       = 2,
 346 };
 347
 348 static struct xfrm6_tunnel xfrm46_tunnel_handler = {
 349         .handler        = xfrm6_tunnel_rcv,
 350         .err_handler    = xfrm6_tunnel_err,
 351         .priority       = 2,
 352 };
 353
 354 static int __init xfrm6_tunnel_init(void)
 355 {
 356         if (xfrm_register_type(&xfrm6_tunnel_type, AF_INET6) < 0)
 357                 goto err;
 358         if (xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6))
 359                 goto unreg;
 360         if (xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET))
 361                 goto dereg6;
 362         if (xfrm6_tunnel_spi_init() < 0)
 363                 goto dereg46;
 364         return 0;
 365
 366 dereg46:
 367         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 368 dereg6:
 369         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 370 unreg:
 371         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 372 err:
 373         return -EAGAIN;
 374 }
 375
 376 static void __exit xfrm6_tunnel_fini(void)
 377 {
 378         xfrm6_tunnel_spi_fini();
 379         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 380         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 381         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 382 }
 383
 384 module_init(xfrm6_tunnel_init);
 385 module_exit(xfrm6_tunnel_fini);
 386 MODULE_LICENSE("GPL");
 387 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);