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 #include <net/netns/generic.h>
  34
  35 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  36 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  37
  38 #define XFRM6_TUNNEL_SPI_MIN    1
  39 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  40
  41 struct xfrm6_tunnel_net {
  42         struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  43         struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  44         u32 spi;
  45 };
  46
  47 static int xfrm6_tunnel_net_id __read_mostly;
  48 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
  49 {
  50         return net_generic(net, xfrm6_tunnel_net_id);
  51 }
  52
  53 /*
  54  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  55  * per xfrm_address_t.
  56  */
  57 struct xfrm6_tunnel_spi {
  58         struct hlist_node       list_byaddr;
  59         struct hlist_node       list_byspi;
  60         xfrm_address_t          addr;
  61         u32                     spi;
  62         atomic_t                refcnt;
  63         struct rcu_head         rcu_head;
  64 };
  65
  66 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
  67
  68 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
  69
  70 static inline unsigned xfrm6_tunnel_spi_hash_byaddr(xfrm_address_t *addr)
  71 {
  72         unsigned h;
  73
  74         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
  75         h ^= h >> 16;
  76         h ^= h >> 8;
  77         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
  78
  79         return h;
  80 }
  81
  82 static inline unsigned xfrm6_tunnel_spi_hash_byspi(u32 spi)
  83 {
  84         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
  85 }
  86
  87
  88 static int __init xfrm6_tunnel_spi_init(void)
  89 {
  90         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
  91                                                   sizeof(struct xfrm6_tunnel_spi),
  92                                                   0, SLAB_HWCACHE_ALIGN,
  93                                                   NULL);
  94         if (!xfrm6_tunnel_spi_kmem)
  95                 return -ENOMEM;
  96         return 0;
  97 }
  98
  99 static void xfrm6_tunnel_spi_fini(void)
 100 {
 101         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 102 }
 103
 104 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
 105 {
 106         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 107         struct xfrm6_tunnel_spi *x6spi;
 108         struct hlist_node *pos;
 109
 110         hlist_for_each_entry_rcu(x6spi, pos,
 111                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 112                              list_byaddr) {
 113                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
 114                         return x6spi;
 115         }
 116
 117         return NULL;
 118 }
 119
 120 __be32 xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr)
 121 {
 122         struct xfrm6_tunnel_spi *x6spi;
 123         u32 spi;
 124
 125         rcu_read_lock_bh();
 126         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 127         spi = x6spi ? x6spi->spi : 0;
 128         rcu_read_unlock_bh();
 129         return htonl(spi);
 130 }
 131
 132 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 133
 134 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
 135 {
 136         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 137         struct xfrm6_tunnel_spi *x6spi;
 138         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 139         struct hlist_node *pos;
 140
 141         hlist_for_each_entry(x6spi, pos,
 142                              &xfrm6_tn->spi_byspi[index],
 143                              list_byspi) {
 144                 if (x6spi->spi == spi)
 145                         return -1;
 146         }
 147         return index;
 148 }
 149
 150 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 151 {
 152         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 153         u32 spi;
 154         struct xfrm6_tunnel_spi *x6spi;
 155         int index;
 156
 157         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
 158             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
 159                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
 160         else
 161                 xfrm6_tn->spi++;
 162
 163         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 164                 index = __xfrm6_tunnel_spi_check(net, spi);
 165                 if (index >= 0)
 166                         goto alloc_spi;
 167         }
 168         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
 169                 index = __xfrm6_tunnel_spi_check(net, spi);
 170                 if (index >= 0)
 171                         goto alloc_spi;
 172         }
 173         spi = 0;
 174         goto out;
 175 alloc_spi:
 176         xfrm6_tn->spi = spi;
 177         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 178         if (!x6spi)
 179                 goto out;
 180
 181         INIT_RCU_HEAD(&x6spi->rcu_head);
 182         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 183         x6spi->spi = spi;
 184         atomic_set(&x6spi->refcnt, 1);
 185
 186         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
 187
 188         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 189         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
 190 out:
 191         return spi;
 192 }
 193
 194 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 195 {
 196         struct xfrm6_tunnel_spi *x6spi;
 197         u32 spi;
 198
 199         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 200         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 201         if (x6spi) {
 202                 atomic_inc(&x6spi->refcnt);
 203                 spi = x6spi->spi;
 204         } else
 205                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
 206         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 207
 208         return htonl(spi);
 209 }
 210
 211 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 212
 213 static void x6spi_destroy_rcu(struct rcu_head *head)
 214 {
 215         kmem_cache_free(xfrm6_tunnel_spi_kmem,
 216                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 217 }
 218
 219 void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 220 {
 221         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 222         struct xfrm6_tunnel_spi *x6spi;
 223         struct hlist_node *pos, *n;
 224
 225         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 226
 227         hlist_for_each_entry_safe(x6spi, pos, n,
 228                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 229                                   list_byaddr)
 230         {
 231                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 232                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 233                                 hlist_del_rcu(&x6spi->list_byaddr);
 234                                 hlist_del_rcu(&x6spi->list_byspi);
 235                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
 236                                 break;
 237                         }
 238                 }
 239         }
 240         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 241 }
 242
 243 EXPORT_SYMBOL(xfrm6_tunnel_free_spi);
 244
 245 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 246 {
 247         skb_push(skb, -skb_network_offset(skb));
 248         return 0;
 249 }
 250
 251 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 252 {
 253         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 254 }
 255
 256 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 257 {
 258         struct net *net = dev_net(skb->dev);
 259         struct ipv6hdr *iph = ipv6_hdr(skb);
 260         __be32 spi;
 261
 262         spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&iph->saddr);
 263         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
 264 }
 265
 266 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 267                             u8 type, u8 code, int offset, __be32 info)
 268 {
 269         /* xfrm6_tunnel native err handling */
 270         switch (type) {
 271         case ICMPV6_DEST_UNREACH:
 272                 switch (code) {
 273                 case ICMPV6_NOROUTE:
 274                 case ICMPV6_ADM_PROHIBITED:
 275                 case ICMPV6_NOT_NEIGHBOUR:
 276                 case ICMPV6_ADDR_UNREACH:
 277                 case ICMPV6_PORT_UNREACH:
 278                 default:
 279                         break;
 280                 }
 281                 break;
 282         case ICMPV6_PKT_TOOBIG:
 283                 break;
 284         case ICMPV6_TIME_EXCEED:
 285                 switch (code) {
 286                 case ICMPV6_EXC_HOPLIMIT:
 287                         break;
 288                 case ICMPV6_EXC_FRAGTIME:
 289                 default:
 290                         break;
 291                 }
 292                 break;
 293         case ICMPV6_PARAMPROB:
 294                 switch (code) {
 295                 case ICMPV6_HDR_FIELD: break;
 296                 case ICMPV6_UNK_NEXTHDR: break;
 297                 case ICMPV6_UNK_OPTION: break;
 298                 }
 299                 break;
 300         default:
 301                 break;
 302         }
 303
 304         return 0;
 305 }
 306
 307 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 308 {
 309         if (x->props.mode != XFRM_MODE_TUNNEL)
 310                 return -EINVAL;
 311
 312         if (x->encap)
 313                 return -EINVAL;
 314
 315         x->props.header_len = sizeof(struct ipv6hdr);
 316
 317         return 0;
 318 }
 319
 320 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 321 {
 322         struct net *net = xs_net(x);
 323
 324         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
 325 }
 326
 327 static const struct xfrm_type xfrm6_tunnel_type = {
 328         .description    = "IP6IP6",
 329         .owner          = THIS_MODULE,
 330         .proto          = IPPROTO_IPV6,
 331         .init_state     = xfrm6_tunnel_init_state,
 332         .destructor     = xfrm6_tunnel_destroy,
 333         .input          = xfrm6_tunnel_input,
 334         .output         = xfrm6_tunnel_output,
 335 };
 336
 337 static struct xfrm6_tunnel xfrm6_tunnel_handler = {
 338         .handler        = xfrm6_tunnel_rcv,
 339         .err_handler    = xfrm6_tunnel_err,
 340         .priority       = 2,
 341 };
 342
 343 static struct xfrm6_tunnel xfrm46_tunnel_handler = {
 344         .handler        = xfrm6_tunnel_rcv,
 345         .err_handler    = xfrm6_tunnel_err,
 346         .priority       = 2,
 347 };
 348
 349 static int __net_init xfrm6_tunnel_net_init(struct net *net)
 350 {
 351         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 352         unsigned int i;
 353
 354         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 355                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
 356         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 357                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
 358         xfrm6_tn->spi = 0;
 359
 360         return 0;
 361 }
 362
 363 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
 364 {
 365 }
 366
 367 static struct pernet_operations xfrm6_tunnel_net_ops = {
 368         .init   = xfrm6_tunnel_net_init,
 369         .exit   = xfrm6_tunnel_net_exit,
 370         .id     = &xfrm6_tunnel_net_id,
 371         .size   = sizeof(struct xfrm6_tunnel_net),
 372 };
 373
 374 static int __init xfrm6_tunnel_init(void)
 375 {
 376         int rv;
 377
 378         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
 379         if (rv < 0)
 380                 goto err;
 381         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
 382         if (rv < 0)
 383                 goto unreg;
 384         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
 385         if (rv < 0)
 386                 goto dereg6;
 387         rv = xfrm6_tunnel_spi_init();
 388         if (rv < 0)
 389                 goto dereg46;
 390         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
 391         if (rv < 0)
 392                 goto deregspi;
 393         return 0;
 394
 395 deregspi:
 396         xfrm6_tunnel_spi_fini();
 397 dereg46:
 398         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 399 dereg6:
 400         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 401 unreg:
 402         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 403 err:
 404         return rv;
 405 }
 406
 407 static void __exit xfrm6_tunnel_fini(void)
 408 {
 409         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 410         xfrm6_tunnel_spi_fini();
 411         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 412         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 413         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 414 }
 415
 416 module_init(xfrm6_tunnel_init);
 417 module_exit(xfrm6_tunnel_fini);
 418 MODULE_LICENSE("GPL");
 419 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);