net/ipv6/xfrm6_tunnel.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C)2003,2004 USAGI/WIDE Project
   4  *
   5  * Authors      Mitsuru KANDA  <mk@linux-ipv6.org>
   6  *              YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
   7  *
   8  * Based on net/ipv4/xfrm4_tunnel.c
   9  */
  10 #include <linux/module.h>
  11 #include <linux/xfrm.h>
  12 #include <linux/slab.h>
  13 #include <linux/rculist.h>
  14 #include <net/ip.h>
  15 #include <net/xfrm.h>
  16 #include <net/ipv6.h>
  17 #include <linux/ipv6.h>
  18 #include <linux/icmpv6.h>
  19 #include <linux/mutex.h>
  20 #include <net/netns/generic.h>
  21
  22 #define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
  23 #define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
  24
  25 #define XFRM6_TUNNEL_SPI_MIN    1
  26 #define XFRM6_TUNNEL_SPI_MAX    0xffffffff
  27
  28 struct xfrm6_tunnel_net {
  29         struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
  30         struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
  31         u32 spi;
  32 };
  33
  34 static unsigned int xfrm6_tunnel_net_id __read_mostly;
  35 static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
  36 {
  37         return net_generic(net, xfrm6_tunnel_net_id);
  38 }
  39
  40 /*
  41  * xfrm_tunnel_spi things are for allocating unique id ("spi")
  42  * per xfrm_address_t.
  43  */
  44 struct xfrm6_tunnel_spi {
  45         struct hlist_node       list_byaddr;
  46         struct hlist_node       list_byspi;
  47         xfrm_address_t          addr;
  48         u32                     spi;
  49         refcount_t              refcnt;
  50         struct rcu_head         rcu_head;
  51 };
  52
  53 static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
  54
  55 static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
  56
  57 static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
  58 {
  59         unsigned int h;
  60
  61         h = ipv6_addr_hash((const struct in6_addr *)addr);
  62         h ^= h >> 16;
  63         h ^= h >> 8;
  64         h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
  65
  66         return h;
  67 }
  68
  69 static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
  70 {
  71         return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
  72 }
  73
  74 static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
  75 {
  76         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
  77         struct xfrm6_tunnel_spi *x6spi;
  78
  79         hlist_for_each_entry_rcu(x6spi,
  80                              &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
  81                              list_byaddr, lockdep_is_held(&xfrm6_tunnel_spi_lock)) {
  82                 if (xfrm6_addr_equal(&x6spi->addr, saddr))
  83                         return x6spi;
  84         }
  85
  86         return NULL;
  87 }
  88
  89 __be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
  90 {
  91         struct xfrm6_tunnel_spi *x6spi;
  92         u32 spi;
  93
  94         rcu_read_lock_bh();
  95         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
  96         spi = x6spi ? x6spi->spi : 0;
  97         rcu_read_unlock_bh();
  98         return htonl(spi);
  99 }
 100 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 101
 102 static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
 103 {
 104         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 105         struct xfrm6_tunnel_spi *x6spi;
 106         int index = xfrm6_tunnel_spi_hash_byspi(spi);
 107
 108         hlist_for_each_entry(x6spi,
 109                              &xfrm6_tn->spi_byspi[index],
 110                              list_byspi) {
 111                 if (x6spi->spi == spi)
 112                         return -1;
 113         }
 114         return index;
 115 }
 116
 117 static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 118 {
 119         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 120         u32 spi;
 121         struct xfrm6_tunnel_spi *x6spi;
 122         int index;
 123
 124         if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
 125             xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
 126                 xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
 127         else
 128                 xfrm6_tn->spi++;
 129
 130         for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
 131                 index = __xfrm6_tunnel_spi_check(net, spi);
 132                 if (index >= 0)
 133                         goto alloc_spi;
 134
 135                 if (spi == XFRM6_TUNNEL_SPI_MAX)
 136                         break;
 137         }
 138         for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
 139                 index = __xfrm6_tunnel_spi_check(net, spi);
 140                 if (index >= 0)
 141                         goto alloc_spi;
 142         }
 143         spi = 0;
 144         goto out;
 145 alloc_spi:
 146         xfrm6_tn->spi = spi;
 147         x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
 148         if (!x6spi)
 149                 goto out;
 150
 151         memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
 152         x6spi->spi = spi;
 153         refcount_set(&x6spi->refcnt, 1);
 154
 155         hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
 156
 157         index = xfrm6_tunnel_spi_hash_byaddr(saddr);
 158         hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
 159 out:
 160         return spi;
 161 }
 162
 163 __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 164 {
 165         struct xfrm6_tunnel_spi *x6spi;
 166         u32 spi;
 167
 168         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 169         x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
 170         if (x6spi) {
 171                 refcount_inc(&x6spi->refcnt);
 172                 spi = x6spi->spi;
 173         } else
 174                 spi = __xfrm6_tunnel_alloc_spi(net, saddr);
 175         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 176
 177         return htonl(spi);
 178 }
 179 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
 180
 181 static void x6spi_destroy_rcu(struct rcu_head *head)
 182 {
 183         kmem_cache_free(xfrm6_tunnel_spi_kmem,
 184                         container_of(head, struct xfrm6_tunnel_spi, rcu_head));
 185 }
 186
 187 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 188 {
 189         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 190         struct xfrm6_tunnel_spi *x6spi;
 191         struct hlist_node *n;
 192
 193         spin_lock_bh(&xfrm6_tunnel_spi_lock);
 194
 195         hlist_for_each_entry_safe(x6spi, n,
 196                                   &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
 197                                   list_byaddr)
 198         {
 199                 if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
 200                         if (refcount_dec_and_test(&x6spi->refcnt)) {
 201                                 hlist_del_rcu(&x6spi->list_byaddr);
 202                                 hlist_del_rcu(&x6spi->list_byspi);
 203                                 call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
 204                                 break;
 205                         }
 206                 }
 207         }
 208         spin_unlock_bh(&xfrm6_tunnel_spi_lock);
 209 }
 210
 211 static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 212 {
 213         skb_push(skb, -skb_network_offset(skb));
 214         return 0;
 215 }
 216
 217 static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 218 {
 219         return skb_network_header(skb)[IP6CB(skb)->nhoff];
 220 }
 221
 222 static int xfrm6_tunnel_rcv(struct sk_buff *skb)
 223 {
 224         struct net *net = dev_net(skb->dev);
 225         const struct ipv6hdr *iph = ipv6_hdr(skb);
 226         __be32 spi;
 227
 228         spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
 229         return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi, NULL);
 230 }
 231
 232 static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 233                             u8 type, u8 code, int offset, __be32 info)
 234 {
 235         /* xfrm6_tunnel native err handling */
 236         switch (type) {
 237         case ICMPV6_DEST_UNREACH:
 238                 switch (code) {
 239                 case ICMPV6_NOROUTE:
 240                 case ICMPV6_ADM_PROHIBITED:
 241                 case ICMPV6_NOT_NEIGHBOUR:
 242                 case ICMPV6_ADDR_UNREACH:
 243                 case ICMPV6_PORT_UNREACH:
 244                 default:
 245                         break;
 246                 }
 247                 break;
 248         case ICMPV6_PKT_TOOBIG:
 249                 break;
 250         case ICMPV6_TIME_EXCEED:
 251                 switch (code) {
 252                 case ICMPV6_EXC_HOPLIMIT:
 253                         break;
 254                 case ICMPV6_EXC_FRAGTIME:
 255                 default:
 256                         break;
 257                 }
 258                 break;
 259         case ICMPV6_PARAMPROB:
 260                 switch (code) {
 261                 case ICMPV6_HDR_FIELD: break;
 262                 case ICMPV6_UNK_NEXTHDR: break;
 263                 case ICMPV6_UNK_OPTION: break;
 264                 }
 265                 break;
 266         default:
 267                 break;
 268         }
 269
 270         return 0;
 271 }
 272
 273 static int xfrm6_tunnel_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 274 {
 275         if (x->props.mode != XFRM_MODE_TUNNEL) {
 276                 NL_SET_ERR_MSG(extack, "IPv6 tunnel can only be used with tunnel mode");
 277                 return -EINVAL;
 278         }
 279
 280         if (x->encap) {
 281                 NL_SET_ERR_MSG(extack, "IPv6 tunnel is not compatible with encapsulation");
 282                 return -EINVAL;
 283         }
 284
 285         x->props.header_len = sizeof(struct ipv6hdr);
 286
 287         return 0;
 288 }
 289
 290 static void xfrm6_tunnel_destroy(struct xfrm_state *x)
 291 {
 292         struct net *net = xs_net(x);
 293
 294         xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
 295 }
 296
 297 static const struct xfrm_type xfrm6_tunnel_type = {
 298         .owner          = THIS_MODULE,
 299         .proto          = IPPROTO_IPV6,
 300         .init_state     = xfrm6_tunnel_init_state,
 301         .destructor     = xfrm6_tunnel_destroy,
 302         .input          = xfrm6_tunnel_input,
 303         .output         = xfrm6_tunnel_output,
 304 };
 305
 306 static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
 307         .handler        = xfrm6_tunnel_rcv,
 308         .err_handler    = xfrm6_tunnel_err,
 309         .priority       = 3,
 310 };
 311
 312 static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
 313         .handler        = xfrm6_tunnel_rcv,
 314         .err_handler    = xfrm6_tunnel_err,
 315         .priority       = 3,
 316 };
 317
 318 static int __net_init xfrm6_tunnel_net_init(struct net *net)
 319 {
 320         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 321         unsigned int i;
 322
 323         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 324                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
 325         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 326                 INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
 327         xfrm6_tn->spi = 0;
 328
 329         return 0;
 330 }
 331
 332 static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
 333 {
 334         struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
 335         unsigned int i;
 336
 337         xfrm_flush_gc();
 338         xfrm_state_flush(net, 0, false, true);
 339
 340         for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
 341                 WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byaddr[i]));
 342
 343         for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
 344                 WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byspi[i]));
 345 }
 346
 347 static struct pernet_operations xfrm6_tunnel_net_ops = {
 348         .init   = xfrm6_tunnel_net_init,
 349         .exit   = xfrm6_tunnel_net_exit,
 350         .id     = &xfrm6_tunnel_net_id,
 351         .size   = sizeof(struct xfrm6_tunnel_net),
 352 };
 353
 354 static int __init xfrm6_tunnel_init(void)
 355 {
 356         int rv;
 357
 358         xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
 359                                                   sizeof(struct xfrm6_tunnel_spi),
 360                                                   0, SLAB_HWCACHE_ALIGN,
 361                                                   NULL);
 362         if (!xfrm6_tunnel_spi_kmem)
 363                 return -ENOMEM;
 364         rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
 365         if (rv < 0)
 366                 goto out_pernet;
 367         rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
 368         if (rv < 0)
 369                 goto out_type;
 370         rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
 371         if (rv < 0)
 372                 goto out_xfrm6;
 373         rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
 374         if (rv < 0)
 375                 goto out_xfrm46;
 376         return 0;
 377
 378 out_xfrm46:
 379         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 380 out_xfrm6:
 381         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 382 out_type:
 383         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 384 out_pernet:
 385         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 386         return rv;
 387 }
 388
 389 static void __exit xfrm6_tunnel_fini(void)
 390 {
 391         xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
 392         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
 393         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
 394         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
 395         /* Someone maybe has gotten the xfrm6_tunnel_spi.
 396          * So need to wait it.
 397          */
 398         rcu_barrier();
 399         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 400 }
 401
 402 module_init(xfrm6_tunnel_init);
 403 module_exit(xfrm6_tunnel_fini);
 404 MODULE_LICENSE("GPL");
 405 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);