linux/net/ipv6/xfrm6_tunnel.c
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   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
  42struct 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
  48static int xfrm6_tunnel_net_id __read_mostly;
  49static 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 */
  58struct 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
  67static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
  68
  69static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
  70
  71static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
  72{
  73        unsigned int 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
  83static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
  84{
  85        return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
  86}
  87
  88static 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
 116EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 117
 118static 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
 134static 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;
 159alloc_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]);
 173out:
 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
 194EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 195
 196static 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
 202static 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
 226static 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
 232static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 233{
 234        return skb_network_header(skb)[IP6CB(skb)->nhoff];
 235}
 236
 237static 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);
 245}
 246
 247static 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
 288static 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
 301static 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
 308static 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
 318static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
 319        .handler        = xfrm6_tunnel_rcv,
 320        .err_handler    = xfrm6_tunnel_err,
 321        .priority       = 2,
 322};
 323
 324static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
 325        .handler        = xfrm6_tunnel_rcv,
 326        .err_handler    = xfrm6_tunnel_err,
 327        .priority       = 2,
 328};
 329
 330static 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
 344static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
 345{
 346}
 347
 348static 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
 355static 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
 379out_xfrm46:
 380        xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 381out_xfrm6:
 382        xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 383out_type:
 384        unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 385out_pernet:
 386        kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 387        return rv;
 388}
 389
 390static 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
 399module_init(xfrm6_tunnel_init);
 400module_exit(xfrm6_tunnel_fini);
 401MODULE_LICENSE("GPL");
 402MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);
 403
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