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, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Authors      Mitsuru KANDA  <mk@linux-ipv6.org>
  18  *              YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
  19  *
  20  * Based on net/ipv4/xfrm4_tunnel.c
  21  *
  22  */
  23 #include <linux/module.h>
  24 #include <linux/xfrm.h>
  25 #include <linux/slab.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 int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
  71 {
  72         unsigned int h;
  73
  74         h = ipv6_addr_hash((const struct in6_addr *)addr);
  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 int 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, const xfrm_address_t *saddr)
  88 {
  89         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
  90         struct xfrm6_tunnel_spi *x6spi;
  91
  92         hlist_for_each_entry_rcu(x6spi,
  93                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
  94                              list_byaddr) {
  95                 if (xfrm6_addr_equal(&x6spi->addr, saddr))
  96                         return x6spi;
  97         }
  98
  99         return NULL;
 100 }
 101
 102 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
 103 {
 104         struct xfrm6_tunnel_spi *x6spi;
 105         u32 spi;
 106
 107         rcu_read_lock_bh();
 108         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 109         spi = x6spi ? x6spi->spi : 0;
 110         rcu_read_unlock_bh();
 111         return htonl(spi);
 112 }
 113
 114 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 115
 116 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
 117 {
 118         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 119         struct xfrm6_tunnel_spi *x6spi;
 120         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 121
 122         hlist_for_each_entry(x6spi,
 123                              &xfrm6_tn->spi_byspi[index],
 124                              list_byspi) {
 125                 if (x6spi->spi == spi)
 126                         return -1;
 127         }
 128         return index;
 129 }
 130
 131 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 132 {
 133         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 134         u32 spi;
 135         struct xfrm6_tunnel_spi *x6spi;
 136         int index;
 137
 138         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
 139             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
 140                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
 141         else
 142                 xfrm6_tn->spi++;
 143
 144         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 145                 index = __xfrm6_tunnel_spi_check(net, spi);
 146                 if (index >= 0)
 147                         goto alloc_spi;
 148         }
 149         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
 150                 index = __xfrm6_tunnel_spi_check(net, spi);
 151                 if (index >= 0)
 152                         goto alloc_spi;
 153         }
 154         spi = 0;
 155         goto out;
 156 alloc_spi:
 157         xfrm6_tn->spi = spi;
 158         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 159         if (!x6spi)
 160                 goto out;
 161
 162         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 163         x6spi->spi = spi;
 164         atomic_set(&x6spi->refcnt, 1);
 165
 166         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
 167
 168         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 169         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
 170 out:
 171         return spi;
 172 }
 173
 174 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 175 {
 176         struct xfrm6_tunnel_spi *x6spi;
 177         u32 spi;
 178
 179         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 180         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 181         if (x6spi) {
 182                 atomic_inc(&x6spi->refcnt);
 183                 spi = x6spi->spi;
 184         } else
 185                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
 186         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 187
 188         return htonl(spi);
 189 }
 190
 191 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 192
 193 static void x6spi_destroy_rcu(struct rcu_head *head)
 194 {
 195         kmem_cache_free(xfrm6_tunnel_spi_kmem,
 196                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 197 }
 198
 199 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 200 {
 201         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 202         struct xfrm6_tunnel_spi *x6spi;
 203         struct hlist_node *n;
 204
 205         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 206
 207         hlist_for_each_entry_safe(x6spi, n,
 208                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 209                                   list_byaddr)
 210         {
 211                 if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
 212                         if (atomic_dec_and_test(&x6spi->refcnt)) {
 213                                 hlist_del_rcu(&x6spi->list_byaddr);
 214                                 hlist_del_rcu(&x6spi->list_byspi);
 215                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
 216                                 break;
 217                         }
 218                 }
 219         }
 220         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 221 }
 222
 223 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 224 {
 225         skb_push(skb, -skb_network_offset(skb));
 226         return 0;
 227 }
 228
 229 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 230 {
 231         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 232 }
 233
 234 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 235 {
 236         struct net *net = dev_net(skb->dev);
 237         const struct ipv6hdr *iph = ipv6_hdr(skb);
 238         __be32 spi;
 239
 240         spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
 241         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi);
 242 }
 243
 244 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 245                             u8 type, u8 code, int offset, __be32 info)
 246 {
 247         /* xfrm6_tunnel native err handling */
 248         switch (type) {
 249         case ICMPV6_DEST_UNREACH:
 250                 switch (code) {
 251                 case ICMPV6_NOROUTE:
 252                 case ICMPV6_ADM_PROHIBITED:
 253                 case ICMPV6_NOT_NEIGHBOUR:
 254                 case ICMPV6_ADDR_UNREACH:
 255                 case ICMPV6_PORT_UNREACH:
 256                 default:
 257                         break;
 258                 }
 259                 break;
 260         case ICMPV6_PKT_TOOBIG:
 261                 break;
 262         case ICMPV6_TIME_EXCEED:
 263                 switch (code) {
 264                 case ICMPV6_EXC_HOPLIMIT:
 265                         break;
 266                 case ICMPV6_EXC_FRAGTIME:
 267                 default:
 268                         break;
 269                 }
 270                 break;
 271         case ICMPV6_PARAMPROB:
 272                 switch (code) {
 273                 case ICMPV6_HDR_FIELD: break;
 274                 case ICMPV6_UNK_NEXTHDR: break;
 275                 case ICMPV6_UNK_OPTION: break;
 276                 }
 277                 break;
 278         default:
 279                 break;
 280         }
 281
 282         return 0;
 283 }
 284
 285 static int xfrm6_tunnel_init_state(struct xfrm_state *x)
 286 {
 287         if (x->props.mode != XFRM_MODE_TUNNEL)
 288                 return -EINVAL;
 289
 290         if (x->encap)
 291                 return -EINVAL;
 292
 293         x->props.header_len = sizeof(struct ipv6hdr);
 294
 295         return 0;
 296 }
 297
 298 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 299 {
 300         struct net *net = xs_net(x);
 301
 302         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
 303 }
 304
 305 static const struct xfrm_type xfrm6_tunnel_type = {
 306         .description    = "IP6IP6",
 307         .owner          = THIS_MODULE,
 308         .proto          = IPPROTO_IPV6,
 309         .init_state     = xfrm6_tunnel_init_state,
 310         .destructor     = xfrm6_tunnel_destroy,
 311         .input          = xfrm6_tunnel_input,
 312         .output         = xfrm6_tunnel_output,
 313 };
 314
 315 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
 316         .handler        = xfrm6_tunnel_rcv,
 317         .err_handler    = xfrm6_tunnel_err,
 318         .priority       = 2,
 319 };
 320
 321 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
 322         .handler        = xfrm6_tunnel_rcv,
 323         .err_handler    = xfrm6_tunnel_err,
 324         .priority       = 2,
 325 };
 326
 327 static int __net_init xfrm6_tunnel_net_init(struct net *net)
 328 {
 329         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 330         unsigned int i;
 331
 332         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 333                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
 334         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 335                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
 336         xfrm6_tn->spi = 0;
 337
 338         return 0;
 339 }
 340
 341 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
 342 {
 343 }
 344
 345 static struct pernet_operations xfrm6_tunnel_net_ops = {
 346         .init   = xfrm6_tunnel_net_init,
 347         .exit   = xfrm6_tunnel_net_exit,
 348         .id     = &xfrm6_tunnel_net_id,
 349         .size   = sizeof(struct xfrm6_tunnel_net),
 350 };
 351
 352 static int __init xfrm6_tunnel_init(void)
 353 {
 354         int rv;
 355
 356         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 357                                                   sizeof(struct xfrm6_tunnel_spi),
 358                                                   0, SLAB_HWCACHE_ALIGN,
 359                                                   NULL);
 360         if (!xfrm6_tunnel_spi_kmem)
 361                 return -ENOMEM;
 362         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
 363         if (rv < 0)
 364                 goto out_pernet;
 365         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
 366         if (rv < 0)
 367                 goto out_type;
 368         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
 369         if (rv < 0)
 370                 goto out_xfrm6;
 371         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
 372         if (rv < 0)
 373                 goto out_xfrm46;
 374         return 0;
 375
 376 out_xfrm46:
 377         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 378 out_xfrm6:
 379         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 380 out_type:
 381         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 382 out_pernet:
 383         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 384         return rv;
 385 }
 386
 387 static void __exit xfrm6_tunnel_fini(void)
 388 {
 389         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 390         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 391         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 392         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 393         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 394 }
 395
 396 module_init(xfrm6_tunnel_init);
 397 module_exit(xfrm6_tunnel_fini);
 398 MODULE_LICENSE("GPL");
 399 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);