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 xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
  72 {
  73         unsigned h;
  74
  75         h = (__force u32)(addr->a6[0] ^ addr->a6[1] ^ addr->a6[2] ^ addr->a6[3]);
  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 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         struct hlist_node *pos;
  93
  94         hlist_for_each_entry_rcu(x6spi, pos,
  95                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
  96                              list_byaddr) {
  97                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0)
  98                         return x6spi;
  99         }
 100
 101         return NULL;
 102 }
 103
 104 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
 105 {
 106         struct xfrm6_tunnel_spi *x6spi;
 107         u32 spi;
 108
 109         rcu_read_lock_bh();
 110         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 111         spi = x6spi ? x6spi->spi : 0;
 112         rcu_read_unlock_bh();
 113         return htonl(spi);
 114 }
 115
 116 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 117
 118 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
 119 {
 120         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 121         struct xfrm6_tunnel_spi *x6spi;
 122         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 123         struct hlist_node *pos;
 124
 125         hlist_for_each_entry(x6spi, pos,
 126                              &xfrm6_tn->spi_byspi[index],
 127                              list_byspi) {
 128                 if (x6spi->spi == spi)
 129                         return -1;
 130         }
 131         return index;
 132 }
 133
 134 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 135 {
 136         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 137         u32 spi;
 138         struct xfrm6_tunnel_spi *x6spi;
 139         int index;
 140
 141         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
 142             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
 143                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
 144         else
 145                 xfrm6_tn->spi++;
 146
 147         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 148                 index = __xfrm6_tunnel_spi_check(net, spi);
 149                 if (index >= 0)
 150                         goto alloc_spi;
 151         }
 152         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
 153                 index = __xfrm6_tunnel_spi_check(net, spi);
 154                 if (index >= 0)
 155                         goto alloc_spi;
 156         }
 157         spi = 0;
 158         goto out;
 159 alloc_spi:
 160         xfrm6_tn->spi = spi;
 161         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 162         if (!x6spi)
 163                 goto out;
 164
 165         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 166         x6spi->spi = spi;
 167         atomic_set(&x6spi->refcnt, 1);
 168
 169         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
 170
 171         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 172         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
 173 out:
 174         return spi;
 175 }
 176
 177 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 178 {
 179         struct xfrm6_tunnel_spi *x6spi;
 180         u32 spi;
 181
 182         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 183         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 184         if (x6spi) {
 185                 atomic_inc(&x6spi->refcnt);
 186                 spi = x6spi->spi;
 187         } else
 188                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
 189         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 190
 191         return htonl(spi);
 192 }
 193
 194 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 195
 196 static void x6spi_destroy_rcu(struct rcu_head *head)
 197 {
 198         kmem_cache_free(xfrm6_tunnel_spi_kmem,
 199                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 200 }
 201
 202 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 203 {
 204         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 205         struct xfrm6_tunnel_spi *x6spi;
 206         struct hlist_node *pos, *n;
 207
 208         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 209
 210         hlist_for_each_entry_safe(x6spi, pos, n,
 211                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 212                                   list_byaddr)
 213         {
 214                 if (memcmp(&x6spi->addr, saddr, sizeof(x6spi->addr)) == 0) {
 215                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 216                                 hlist_del_rcu(&x6spi->list_byaddr);
 217                                 hlist_del_rcu(&x6spi->list_byspi);
 218                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
 219                                 break;
 220                         }
 221                 }
 222         }
 223         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 224 }
 225
 226 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 227 {
 228         skb_push(skb, -skb_network_offset(skb));
 229         return 0;
 230 }
 231
 232 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 233 {
 234         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 235 }
 236
 237 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 238 {
 239         struct net *net = dev_net(skb->dev);
 240         const struct ipv6hdr *iph = ipv6_hdr(skb);
 241         __be32 spi;
 242
 243         spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
 244         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi) > 0 ? : 0;
 245 }
 246
 247 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 248                             u8 type, u8 code, int offset, __be32 info)
 249 {
 250         /* xfrm6_tunnel native err handling */
 251         switch (type) {
 252         case ICMPV6_DEST_UNREACH:
 253                 switch (code) {
 254                 case ICMPV6_NOROUTE:
 255                 case ICMPV6_ADM_PROHIBITED:
 256                 case ICMPV6_NOT_NEIGHBOUR:
 257                 case ICMPV6_ADDR_UNREACH:
 258                 case ICMPV6_PORT_UNREACH:
 259                 default:
 260                         break;
 261                 }
 262                 break;
 263         case ICMPV6_PKT_TOOBIG:
 264                 break;
 265         case ICMPV6_TIME_EXCEED:
 266                 switch (code) {
 267                 case ICMPV6_EXC_HOPLIMIT:
 268                         break;
 269                 case ICMPV6_EXC_FRAGTIME:
 270                 default:
 271                         break;
 272                 }
 273                 break;
 274         case ICMPV6_PARAMPROB:
 275                 switch (code) {
 276                 case ICMPV6_HDR_FIELD: break;
 277                 case ICMPV6_UNK_NEXTHDR: break;
 278                 case ICMPV6_UNK_OPTION: break;
 279                 }
 280                 break;
 281         default:
 282                 break;
 283         }
 284
 285         return 0;
 286 }
 287
 288 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 289 {
 290         if (x->props.mode != XFRM_MODE_TUNNEL)
 291                 return -EINVAL;
 292
 293         if (x->encap)
 294                 return -EINVAL;
 295
 296         x->props.header_len = sizeof(struct ipv6hdr);
 297
 298         return 0;
 299 }
 300
 301 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 302 {
 303         struct net *net = xs_net(x);
 304
 305         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
 306 }
 307
 308 static const struct xfrm_type xfrm6_tunnel_type = {
 309         .description    = "IP6IP6",
 310         .owner          = THIS_MODULE,
 311         .proto          = IPPROTO_IPV6,
 312         .init_state     = xfrm6_tunnel_init_state,
 313         .destructor     = xfrm6_tunnel_destroy,
 314         .input          = xfrm6_tunnel_input,
 315         .output         = xfrm6_tunnel_output,
 316 };
 317
 318 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
 319         .handler        = xfrm6_tunnel_rcv,
 320         .err_handler    = xfrm6_tunnel_err,
 321         .priority       = 2,
 322 };
 323
 324 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
 325         .handler        = xfrm6_tunnel_rcv,
 326         .err_handler    = xfrm6_tunnel_err,
 327         .priority       = 2,
 328 };
 329
 330 static int __net_init xfrm6_tunnel_net_init(struct net *net)
 331 {
 332         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 333         unsigned int i;
 334
 335         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 336                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
 337         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 338                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
 339         xfrm6_tn->spi = 0;
 340
 341         return 0;
 342 }
 343
 344 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
 345 {
 346 }
 347
 348 static struct pernet_operations xfrm6_tunnel_net_ops = {
 349         .init   = xfrm6_tunnel_net_init,
 350         .exit   = xfrm6_tunnel_net_exit,
 351         .id     = &xfrm6_tunnel_net_id,
 352         .size   = sizeof(struct xfrm6_tunnel_net),
 353 };
 354
 355 static int __init xfrm6_tunnel_init(void)
 356 {
 357         int rv;
 358
 359         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 360                                                   sizeof(struct xfrm6_tunnel_spi),
 361                                                   0, SLAB_HWCACHE_ALIGN,
 362                                                   NULL);
 363         if (!xfrm6_tunnel_spi_kmem)
 364                 return -ENOMEM;
 365         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
 366         if (rv < 0)
 367                 goto out_pernet;
 368         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
 369         if (rv < 0)
 370                 goto out_type;
 371         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
 372         if (rv < 0)
 373                 goto out_xfrm6;
 374         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
 375         if (rv < 0)
 376                 goto out_xfrm46;
 377         return 0;
 378
 379 out_xfrm46:
 380         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 381 out_xfrm6:
 382         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 383 out_type:
 384         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 385 out_pernet:
 386         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 387         return rv;
 388 }
 389
 390 static void __exit xfrm6_tunnel_fini(void)
 391 {
 392         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 393         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 394         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 395         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 396         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 397 }
 398
 399 module_init(xfrm6_tunnel_init);
 400 module_exit(xfrm6_tunnel_fini);
 401 MODULE_LICENSE("GPL");
 402 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);