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/slab.h>
  27 #include <linux/rculist.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 #include <net/netns/generic.h>
  35
  36 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  37 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  38
  39 #define XFRM6_TUNNEL_SPI_MIN    1
  40 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  41
  42 struct xfrm6_tunnel_net {
  43         struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  44         struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  45         u32 spi;
  46 };
  47
  48 static int xfrm6_tunnel_net_id __read_mostly;
  49 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
  50 {
  51         return net_generic(net, xfrm6_tunnel_net_id);
  52 }
  53
  54 /*
  55  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  56  * per xfrm_address_t.
  57  */
  58 struct xfrm6_tunnel_spi {
  59         struct hlist_node       list_byaddr;
  60         struct hlist_node       list_byspi;
  61         xfrm_address_t          addr;
  62         u32                     spi;
  63         atomic_t                refcnt;
  64         struct rcu_head         rcu_head;
  65 };
  66
  67 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
  68
  69 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
  70
  71 static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
  72 {
  73         unsigned int h;
  74
  75         h = ipv6_addr_hash((const struct in6_addr *)addr);
  76         h ^= h >> 16;
  77         h ^= h >> 8;
  78         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
  79
  80         return h;
  81 }
  82
  83 static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
  84 {
  85         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
  86 }
  87
  88 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
  89 {
  90         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
  91         struct xfrm6_tunnel_spi *x6spi;
  92
  93         hlist_for_each_entry_rcu(x6spi,
  94                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
  95                              list_byaddr) {
  96                 if (xfrm6_addr_equal(&x6spi->addr, saddr))
  97                         return x6spi;
  98         }
  99
 100         return NULL;
 101 }
 102
 103 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
 104 {
 105         struct xfrm6_tunnel_spi *x6spi;
 106         u32 spi;
 107
 108         rcu_read_lock_bh();
 109         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 110         spi = x6spi ? x6spi->spi : 0;
 111         rcu_read_unlock_bh();
 112         return htonl(spi);
 113 }
 114
 115 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 116
 117 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
 118 {
 119         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 120         struct xfrm6_tunnel_spi *x6spi;
 121         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 122
 123         hlist_for_each_entry(x6spi,
 124                              &xfrm6_tn->spi_byspi[index],
 125                              list_byspi) {
 126                 if (x6spi->spi == spi)
 127                         return -1;
 128         }
 129         return index;
 130 }
 131
 132 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 133 {
 134         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 135         u32 spi;
 136         struct xfrm6_tunnel_spi *x6spi;
 137         int index;
 138
 139         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
 140             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
 141                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
 142         else
 143                 xfrm6_tn->spi++;
 144
 145         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 146                 index = __xfrm6_tunnel_spi_check(net, spi);
 147                 if (index >= 0)
 148                         goto alloc_spi;
 149         }
 150         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
 151                 index = __xfrm6_tunnel_spi_check(net, spi);
 152                 if (index >= 0)
 153                         goto alloc_spi;
 154         }
 155         spi = 0;
 156         goto out;
 157 alloc_spi:
 158         xfrm6_tn->spi = spi;
 159         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 160         if (!x6spi)
 161                 goto out;
 162
 163         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 164         x6spi->spi = spi;
 165         atomic_set(&x6spi->refcnt, 1);
 166
 167         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
 168
 169         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 170         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
 171 out:
 172         return spi;
 173 }
 174
 175 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 176 {
 177         struct xfrm6_tunnel_spi *x6spi;
 178         u32 spi;
 179
 180         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 181         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 182         if (x6spi) {
 183                 atomic_inc(&x6spi->refcnt);
 184                 spi = x6spi->spi;
 185         } else
 186                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
 187         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 188
 189         return htonl(spi);
 190 }
 191
 192 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 193
 194 static void x6spi_destroy_rcu(struct rcu_head *head)
 195 {
 196         kmem_cache_free(xfrm6_tunnel_spi_kmem,
 197                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 198 }
 199
 200 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 201 {
 202         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 203         struct xfrm6_tunnel_spi *x6spi;
 204         struct hlist_node *n;
 205
 206         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 207
 208         hlist_for_each_entry_safe(x6spi, n,
 209                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 210                                   list_byaddr)
 211         {
 212                 if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
 213                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 214                                 hlist_del_rcu(&x6spi->list_byaddr);
 215                                 hlist_del_rcu(&x6spi->list_byspi);
 216                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
 217                                 break;
 218                         }
 219                 }
 220         }
 221         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 222 }
 223
 224 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 225 {
 226         skb_push(skb, -skb_network_offset(skb));
 227         return 0;
 228 }
 229
 230 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 231 {
 232         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 233 }
 234
 235 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 236 {
 237         struct net *net = dev_net(skb->dev);
 238         const struct ipv6hdr *iph = ipv6_hdr(skb);
 239         __be32 spi;
 240
 241         spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
 242         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi);
 243 }
 244
 245 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 246                             u8 type, u8 code, int offset, __be32 info)
 247 {
 248         /* xfrm6_tunnel native err handling */
 249         switch (type) {
 250         case ICMPV6_DEST_UNREACH:
 251                 switch (code) {
 252                 case ICMPV6_NOROUTE:
 253                 case ICMPV6_ADM_PROHIBITED:
 254                 case ICMPV6_NOT_NEIGHBOUR:
 255                 case ICMPV6_ADDR_UNREACH:
 256                 case ICMPV6_PORT_UNREACH:
 257                 default:
 258                         break;
 259                 }
 260                 break;
 261         case ICMPV6_PKT_TOOBIG:
 262                 break;
 263         case ICMPV6_TIME_EXCEED:
 264                 switch (code) {
 265                 case ICMPV6_EXC_HOPLIMIT:
 266                         break;
 267                 case ICMPV6_EXC_FRAGTIME:
 268                 default:
 269                         break;
 270                 }
 271                 break;
 272         case ICMPV6_PARAMPROB:
 273                 switch (code) {
 274                 case ICMPV6_HDR_FIELD: break;
 275                 case ICMPV6_UNK_NEXTHDR: break;
 276                 case ICMPV6_UNK_OPTION: break;
 277                 }
 278                 break;
 279         default:
 280                 break;
 281         }
 282
 283         return 0;
 284 }
 285
 286 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 287 {
 288         if (x->props.mode != XFRM_MODE_TUNNEL)
 289                 return -EINVAL;
 290
 291         if (x->encap)
 292                 return -EINVAL;
 293
 294         x->props.header_len = sizeof(struct ipv6hdr);
 295
 296         return 0;
 297 }
 298
 299 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 300 {
 301         struct net *net = xs_net(x);
 302
 303         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
 304 }
 305
 306 static const struct xfrm_type xfrm6_tunnel_type = {
 307         .description    = "IP6IP6",
 308         .owner          = THIS_MODULE,
 309         .proto          = IPPROTO_IPV6,
 310         .init_state     = xfrm6_tunnel_init_state,
 311         .destructor     = xfrm6_tunnel_destroy,
 312         .input          = xfrm6_tunnel_input,
 313         .output         = xfrm6_tunnel_output,
 314 };
 315
 316 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
 317         .handler        = xfrm6_tunnel_rcv,
 318         .err_handler    = xfrm6_tunnel_err,
 319         .priority       = 2,
 320 };
 321
 322 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
 323         .handler        = xfrm6_tunnel_rcv,
 324         .err_handler    = xfrm6_tunnel_err,
 325         .priority       = 2,
 326 };
 327
 328 static int __net_init xfrm6_tunnel_net_init(struct net *net)
 329 {
 330         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 331         unsigned int i;
 332
 333         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 334                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
 335         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 336                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
 337         xfrm6_tn->spi = 0;
 338
 339         return 0;
 340 }
 341
 342 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
 343 {
 344 }
 345
 346 static struct pernet_operations xfrm6_tunnel_net_ops = {
 347         .init   = xfrm6_tunnel_net_init,
 348         .exit   = xfrm6_tunnel_net_exit,
 349         .id     = &xfrm6_tunnel_net_id,
 350         .size   = sizeof(struct xfrm6_tunnel_net),
 351 };
 352
 353 static int __init xfrm6_tunnel_init(void)
 354 {
 355         int rv;
 356
 357         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 358                                                   sizeof(struct xfrm6_tunnel_spi),
 359                                                   0, SLAB_HWCACHE_ALIGN,
 360                                                   NULL);
 361         if (!xfrm6_tunnel_spi_kmem)
 362                 return -ENOMEM;
 363         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
 364         if (rv < 0)
 365                 goto out_pernet;
 366         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
 367         if (rv < 0)
 368                 goto out_type;
 369         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
 370         if (rv < 0)
 371                 goto out_xfrm6;
 372         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
 373         if (rv < 0)
 374                 goto out_xfrm46;
 375         return 0;
 376
 377 out_xfrm46:
 378         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 379 out_xfrm6:
 380         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 381 out_type:
 382         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 383 out_pernet:
 384         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 385         return rv;
 386 }
 387
 388 static void __exit xfrm6_tunnel_fini(void)
 389 {
 390         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 391         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 392         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 393         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 394         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 395 }
 396
 397 module_init(xfrm6_tunnel_init);
 398 module_exit(xfrm6_tunnel_fini);
 399 MODULE_LICENSE("GPL");
 400 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);