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