net/ipv6/ila/ila_xlat.c

   1 #include <linux/jhash.h>
   2 #include <linux/netfilter.h>
   3 #include <linux/rcupdate.h>
   4 #include <linux/rhashtable.h>
   5 #include <linux/vmalloc.h>
   6 #include <net/genetlink.h>
   7 #include <net/ila.h>
   8 #include <net/netns/generic.h>
   9 #include <uapi/linux/genetlink.h>
  10 #include "ila.h"
  11
  12 struct ila_xlat_params {
  13         struct ila_params ip;
  14         int ifindex;
  15 };
  16
  17 struct ila_map {
  18         struct ila_xlat_params xp;
  19         struct rhash_head node;
  20         struct ila_map __rcu *next;
  21         struct rcu_head rcu;
  22 };
  23
  24 static unsigned int ila_net_id;
  25
  26 struct ila_net {
  27         struct rhashtable rhash_table;
  28         spinlock_t *locks; /* Bucket locks for entry manipulation */
  29         unsigned int locks_mask;
  30         bool hooks_registered;
  31 };
  32
  33 #define LOCKS_PER_CPU 10
  34
  35 static int alloc_ila_locks(struct ila_net *ilan)
  36 {
  37         unsigned int i, size;
  38         unsigned int nr_pcpus = num_possible_cpus();
  39
  40         nr_pcpus = min_t(unsigned int, nr_pcpus, 32UL);
  41         size = roundup_pow_of_two(nr_pcpus * LOCKS_PER_CPU);
  42
  43         if (sizeof(spinlock_t) != 0) {
  44 #ifdef CONFIG_NUMA
  45                 if (size * sizeof(spinlock_t) > PAGE_SIZE)
  46                         ilan->locks = vmalloc(size * sizeof(spinlock_t));
  47                 else
  48 #endif
  49                 ilan->locks = kmalloc_array(size, sizeof(spinlock_t),
  50                                             GFP_KERNEL);
  51                 if (!ilan->locks)
  52                         return -ENOMEM;
  53                 for (i = 0; i < size; i++)
  54                         spin_lock_init(&ilan->locks[i]);
  55         }
  56         ilan->locks_mask = size - 1;
  57
  58         return 0;
  59 }
  60
  61 static u32 hashrnd __read_mostly;
  62 static __always_inline void __ila_hash_secret_init(void)
  63 {
  64         net_get_random_once(&hashrnd, sizeof(hashrnd));
  65 }
  66
  67 static inline u32 ila_locator_hash(struct ila_locator loc)
  68 {
  69         u32 *v = (u32 *)loc.v32;
  70
  71         return jhash_2words(v[0], v[1], hashrnd);
  72 }
  73
  74 static inline spinlock_t *ila_get_lock(struct ila_net *ilan,
  75                                        struct ila_locator loc)
  76 {
  77         return &ilan->locks[ila_locator_hash(loc) & ilan->locks_mask];
  78 }
  79
  80 static inline int ila_cmp_wildcards(struct ila_map *ila,
  81                                     struct ila_addr *iaddr, int ifindex)
  82 {
  83         return (ila->xp.ifindex && ila->xp.ifindex != ifindex);
  84 }
  85
  86 static inline int ila_cmp_params(struct ila_map *ila,
  87                                  struct ila_xlat_params *xp)
  88 {
  89         return (ila->xp.ifindex != xp->ifindex);
  90 }
  91
  92 static int ila_cmpfn(struct rhashtable_compare_arg *arg,
  93                      const void *obj)
  94 {
  95         const struct ila_map *ila = obj;
  96
  97         return (ila->xp.ip.locator_match.v64 != *(__be64 *)arg->key);
  98 }
  99
 100 static inline int ila_order(struct ila_map *ila)
 101 {
 102         int score = 0;
 103
 104         if (ila->xp.ifindex)
 105                 score += 1 << 1;
 106
 107         return score;
 108 }
 109
 110 static const struct rhashtable_params rht_params = {
 111         .nelem_hint = 1024,
 112         .head_offset = offsetof(struct ila_map, node),
 113         .key_offset = offsetof(struct ila_map, xp.ip.locator_match),
 114         .key_len = sizeof(u64), /* identifier */
 115         .max_size = 1048576,
 116         .min_size = 256,
 117         .automatic_shrinking = true,
 118         .obj_cmpfn = ila_cmpfn,
 119 };
 120
 121 static struct genl_family ila_nl_family = {
 122         .hdrsize        = 0,
 123         .name           = ILA_GENL_NAME,
 124         .version        = ILA_GENL_VERSION,
 125         .maxattr        = ILA_ATTR_MAX,
 126         .netnsok        = true,
 127         .parallel_ops   = true,
 128 };
 129
 130 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 131         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 132         [ILA_ATTR_LOCATOR_MATCH] = { .type = NLA_U64, },
 133         [ILA_ATTR_IFINDEX] = { .type = NLA_U32, },
 134         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 135 };
 136
 137 static int parse_nl_config(struct genl_info *info,
 138                            struct ila_xlat_params *xp)
 139 {
 140         memset(xp, 0, sizeof(*xp));
 141
 142         if (info->attrs[ILA_ATTR_LOCATOR])
 143                 xp->ip.locator.v64 = (__force __be64)nla_get_u64(
 144                         info->attrs[ILA_ATTR_LOCATOR]);
 145
 146         if (info->attrs[ILA_ATTR_LOCATOR_MATCH])
 147                 xp->ip.locator_match.v64 = (__force __be64)nla_get_u64(
 148                         info->attrs[ILA_ATTR_LOCATOR_MATCH]);
 149
 150         if (info->attrs[ILA_ATTR_CSUM_MODE])
 151                 xp->ip.csum_mode = nla_get_u8(info->attrs[ILA_ATTR_CSUM_MODE]);
 152
 153         if (info->attrs[ILA_ATTR_IFINDEX])
 154                 xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
 155
 156         return 0;
 157 }
 158
 159 /* Must be called with rcu readlock */
 160 static inline struct ila_map *ila_lookup_wildcards(struct ila_addr *iaddr,
 161                                                    int ifindex,
 162                                                    struct ila_net *ilan)
 163 {
 164         struct ila_map *ila;
 165
 166         ila = rhashtable_lookup_fast(&ilan->rhash_table, &iaddr->loc,
 167                                      rht_params);
 168         while (ila) {
 169                 if (!ila_cmp_wildcards(ila, iaddr, ifindex))
 170                         return ila;
 171                 ila = rcu_access_pointer(ila->next);
 172         }
 173
 174         return NULL;
 175 }
 176
 177 /* Must be called with rcu readlock */
 178 static inline struct ila_map *ila_lookup_by_params(struct ila_xlat_params *xp,
 179                                                    struct ila_net *ilan)
 180 {
 181         struct ila_map *ila;
 182
 183         ila = rhashtable_lookup_fast(&ilan->rhash_table,
 184                                      &xp->ip.locator_match,
 185                                      rht_params);
 186         while (ila) {
 187                 if (!ila_cmp_params(ila, xp))
 188                         return ila;
 189                 ila = rcu_access_pointer(ila->next);
 190         }
 191
 192         return NULL;
 193 }
 194
 195 static inline void ila_release(struct ila_map *ila)
 196 {
 197         kfree_rcu(ila, rcu);
 198 }
 199
 200 static void ila_free_cb(void *ptr, void *arg)
 201 {
 202         struct ila_map *ila = (struct ila_map *)ptr, *next;
 203
 204         /* Assume rcu_readlock held */
 205         while (ila) {
 206                 next = rcu_access_pointer(ila->next);
 207                 ila_release(ila);
 208                 ila = next;
 209         }
 210 }
 211
 212 static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral);
 213
 214 static unsigned int
 215 ila_nf_input(void *priv,
 216              struct sk_buff *skb,
 217              const struct nf_hook_state *state)
 218 {
 219         ila_xlat_addr(skb, false);
 220         return NF_ACCEPT;
 221 }
 222
 223 static struct nf_hook_ops ila_nf_hook_ops[] __read_mostly = {
 224         {
 225                 .hook = ila_nf_input,
 226                 .pf = NFPROTO_IPV6,
 227                 .hooknum = NF_INET_PRE_ROUTING,
 228                 .priority = -1,
 229         },
 230 };
 231
 232 static int ila_add_mapping(struct net *net, struct ila_xlat_params *xp)
 233 {
 234         struct ila_net *ilan = net_generic(net, ila_net_id);
 235         struct ila_map *ila, *head;
 236         spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
 237         int err = 0, order;
 238
 239         if (!ilan->hooks_registered) {
 240                 /* We defer registering net hooks in the namespace until the
 241                  * first mapping is added.
 242                  */
 243                 err = nf_register_net_hooks(net, ila_nf_hook_ops,
 244                                             ARRAY_SIZE(ila_nf_hook_ops));
 245                 if (err)
 246                         return err;
 247
 248                 ilan->hooks_registered = true;
 249         }
 250
 251         ila = kzalloc(sizeof(*ila), GFP_KERNEL);
 252         if (!ila)
 253                 return -ENOMEM;
 254
 255         ila_init_saved_csum(&xp->ip);
 256
 257         ila->xp = *xp;
 258
 259         order = ila_order(ila);
 260
 261         spin_lock(lock);
 262
 263         head = rhashtable_lookup_fast(&ilan->rhash_table,
 264                                       &xp->ip.locator_match,
 265                                       rht_params);
 266         if (!head) {
 267                 /* New entry for the rhash_table */
 268                 err = rhashtable_lookup_insert_fast(&ilan->rhash_table,
 269                                                     &ila->node, rht_params);
 270         } else {
 271                 struct ila_map *tila = head, *prev = NULL;
 272
 273                 do {
 274                         if (!ila_cmp_params(tila, xp)) {
 275                                 err = -EEXIST;
 276                                 goto out;
 277                         }
 278
 279                         if (order > ila_order(tila))
 280                                 break;
 281
 282                         prev = tila;
 283                         tila = rcu_dereference_protected(tila->next,
 284                                 lockdep_is_held(lock));
 285                 } while (tila);
 286
 287                 if (prev) {
 288                         /* Insert in sub list of head */
 289                         RCU_INIT_POINTER(ila->next, tila);
 290                         rcu_assign_pointer(prev->next, ila);
 291                 } else {
 292                         /* Make this ila new head */
 293                         RCU_INIT_POINTER(ila->next, head);
 294                         err = rhashtable_replace_fast(&ilan->rhash_table,
 295                                                       &head->node,
 296                                                       &ila->node, rht_params);
 297                         if (err)
 298                                 goto out;
 299                 }
 300         }
 301
 302 out:
 303         spin_unlock(lock);
 304
 305         if (err)
 306                 kfree(ila);
 307
 308         return err;
 309 }
 310
 311 static int ila_del_mapping(struct net *net, struct ila_xlat_params *xp)
 312 {
 313         struct ila_net *ilan = net_generic(net, ila_net_id);
 314         struct ila_map *ila, *head, *prev;
 315         spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
 316         int err = -ENOENT;
 317
 318         spin_lock(lock);
 319
 320         head = rhashtable_lookup_fast(&ilan->rhash_table,
 321                                       &xp->ip.locator_match, rht_params);
 322         ila = head;
 323
 324         prev = NULL;
 325
 326         while (ila) {
 327                 if (ila_cmp_params(ila, xp)) {
 328                         prev = ila;
 329                         ila = rcu_dereference_protected(ila->next,
 330                                                         lockdep_is_held(lock));
 331                         continue;
 332                 }
 333
 334                 err = 0;
 335
 336                 if (prev) {
 337                         /* Not head, just delete from list */
 338                         rcu_assign_pointer(prev->next, ila->next);
 339                 } else {
 340                         /* It is the head. If there is something in the
 341                          * sublist we need to make a new head.
 342                          */
 343                         head = rcu_dereference_protected(ila->next,
 344                                                          lockdep_is_held(lock));
 345                         if (head) {
 346                                 /* Put first entry in the sublist into the
 347                                  * table
 348                                  */
 349                                 err = rhashtable_replace_fast(
 350                                         &ilan->rhash_table, &ila->node,
 351                                         &head->node, rht_params);
 352                                 if (err)
 353                                         goto out;
 354                         } else {
 355                                 /* Entry no longer used */
 356                                 err = rhashtable_remove_fast(&ilan->rhash_table,
 357                                                              &ila->node,
 358                                                              rht_params);
 359                         }
 360                 }
 361
 362                 ila_release(ila);
 363
 364                 break;
 365         }
 366
 367 out:
 368         spin_unlock(lock);
 369
 370         return err;
 371 }
 372
 373 static int ila_nl_cmd_add_mapping(struct sk_buff *skb, struct genl_info *info)
 374 {
 375         struct net *net = genl_info_net(info);
 376         struct ila_xlat_params p;
 377         int err;
 378
 379         err = parse_nl_config(info, &p);
 380         if (err)
 381                 return err;
 382
 383         return ila_add_mapping(net, &p);
 384 }
 385
 386 static int ila_nl_cmd_del_mapping(struct sk_buff *skb, struct genl_info *info)
 387 {
 388         struct net *net = genl_info_net(info);
 389         struct ila_xlat_params xp;
 390         int err;
 391
 392         err = parse_nl_config(info, &xp);
 393         if (err)
 394                 return err;
 395
 396         ila_del_mapping(net, &xp);
 397
 398         return 0;
 399 }
 400
 401 static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
 402 {
 403         if (nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR,
 404                               (__force u64)ila->xp.ip.locator.v64,
 405                               ILA_ATTR_PAD) ||
 406             nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR_MATCH,
 407                               (__force u64)ila->xp.ip.locator_match.v64,
 408                               ILA_ATTR_PAD) ||
 409             nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
 410             nla_put_u32(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode))
 411                 return -1;
 412
 413         return 0;
 414 }
 415
 416 static int ila_dump_info(struct ila_map *ila,
 417                          u32 portid, u32 seq, u32 flags,
 418                          struct sk_buff *skb, u8 cmd)
 419 {
 420         void *hdr;
 421
 422         hdr = genlmsg_put(skb, portid, seq, &ila_nl_family, flags, cmd);
 423         if (!hdr)
 424                 return -ENOMEM;
 425
 426         if (ila_fill_info(ila, skb) < 0)
 427                 goto nla_put_failure;
 428
 429         genlmsg_end(skb, hdr);
 430         return 0;
 431
 432 nla_put_failure:
 433         genlmsg_cancel(skb, hdr);
 434         return -EMSGSIZE;
 435 }
 436
 437 static int ila_nl_cmd_get_mapping(struct sk_buff *skb, struct genl_info *info)
 438 {
 439         struct net *net = genl_info_net(info);
 440         struct ila_net *ilan = net_generic(net, ila_net_id);
 441         struct sk_buff *msg;
 442         struct ila_xlat_params xp;
 443         struct ila_map *ila;
 444         int ret;
 445
 446         ret = parse_nl_config(info, &xp);
 447         if (ret)
 448                 return ret;
 449
 450         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 451         if (!msg)
 452                 return -ENOMEM;
 453
 454         rcu_read_lock();
 455
 456         ila = ila_lookup_by_params(&xp, ilan);
 457         if (ila) {
 458                 ret = ila_dump_info(ila,
 459                                     info->snd_portid,
 460                                     info->snd_seq, 0, msg,
 461                                     info->genlhdr->cmd);
 462         }
 463
 464         rcu_read_unlock();
 465
 466         if (ret < 0)
 467                 goto out_free;
 468
 469         return genlmsg_reply(msg, info);
 470
 471 out_free:
 472         nlmsg_free(msg);
 473         return ret;
 474 }
 475
 476 struct ila_dump_iter {
 477         struct rhashtable_iter rhiter;
 478 };
 479
 480 static int ila_nl_dump_start(struct netlink_callback *cb)
 481 {
 482         struct net *net = sock_net(cb->skb->sk);
 483         struct ila_net *ilan = net_generic(net, ila_net_id);
 484         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 485
 486         return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
 487                                     GFP_KERNEL);
 488 }
 489
 490 static int ila_nl_dump_done(struct netlink_callback *cb)
 491 {
 492         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 493
 494         rhashtable_walk_exit(&iter->rhiter);
 495
 496         return 0;
 497 }
 498
 499 static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 500 {
 501         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 502         struct rhashtable_iter *rhiter = &iter->rhiter;
 503         struct ila_map *ila;
 504         int ret;
 505
 506         ret = rhashtable_walk_start(rhiter);
 507         if (ret && ret != -EAGAIN)
 508                 goto done;
 509
 510         for (;;) {
 511                 ila = rhashtable_walk_next(rhiter);
 512
 513                 if (IS_ERR(ila)) {
 514                         if (PTR_ERR(ila) == -EAGAIN)
 515                                 continue;
 516                         ret = PTR_ERR(ila);
 517                         goto done;
 518                 } else if (!ila) {
 519                         break;
 520                 }
 521
 522                 while (ila) {
 523                         ret =  ila_dump_info(ila, NETLINK_CB(cb->skb).portid,
 524                                              cb->nlh->nlmsg_seq, NLM_F_MULTI,
 525                                              skb, ILA_CMD_GET);
 526                         if (ret)
 527                                 goto done;
 528
 529                         ila = rcu_access_pointer(ila->next);
 530                 }
 531         }
 532
 533         ret = skb->len;
 534
 535 done:
 536         rhashtable_walk_stop(rhiter);
 537         return ret;
 538 }
 539
 540 static const struct genl_ops ila_nl_ops[] = {
 541         {
 542                 .cmd = ILA_CMD_ADD,
 543                 .doit = ila_nl_cmd_add_mapping,
 544                 .policy = ila_nl_policy,
 545                 .flags = GENL_ADMIN_PERM,
 546         },
 547         {
 548                 .cmd = ILA_CMD_DEL,
 549                 .doit = ila_nl_cmd_del_mapping,
 550                 .policy = ila_nl_policy,
 551                 .flags = GENL_ADMIN_PERM,
 552         },
 553         {
 554                 .cmd = ILA_CMD_GET,
 555                 .doit = ila_nl_cmd_get_mapping,
 556                 .start = ila_nl_dump_start,
 557                 .dumpit = ila_nl_dump,
 558                 .done = ila_nl_dump_done,
 559                 .policy = ila_nl_policy,
 560         },
 561 };
 562
 563 #define ILA_HASH_TABLE_SIZE 1024
 564
 565 static __net_init int ila_init_net(struct net *net)
 566 {
 567         int err;
 568         struct ila_net *ilan = net_generic(net, ila_net_id);
 569
 570         err = alloc_ila_locks(ilan);
 571         if (err)
 572                 return err;
 573
 574         rhashtable_init(&ilan->rhash_table, &rht_params);
 575
 576         return 0;
 577 }
 578
 579 static __net_exit void ila_exit_net(struct net *net)
 580 {
 581         struct ila_net *ilan = net_generic(net, ila_net_id);
 582
 583         rhashtable_free_and_destroy(&ilan->rhash_table, ila_free_cb, NULL);
 584
 585         kvfree(ilan->locks);
 586
 587         if (ilan->hooks_registered)
 588                 nf_unregister_net_hooks(net, ila_nf_hook_ops,
 589                                         ARRAY_SIZE(ila_nf_hook_ops));
 590 }
 591
 592 static struct pernet_operations ila_net_ops = {
 593         .init = ila_init_net,
 594         .exit = ila_exit_net,
 595         .id   = &ila_net_id,
 596         .size = sizeof(struct ila_net),
 597 };
 598
 599 static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral)
 600 {
 601         struct ila_map *ila;
 602         struct ipv6hdr *ip6h = ipv6_hdr(skb);
 603         struct net *net = dev_net(skb->dev);
 604         struct ila_net *ilan = net_generic(net, ila_net_id);
 605         struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 606
 607         /* Assumes skb contains a valid IPv6 header that is pulled */
 608
 609         if (!ila_addr_is_ila(iaddr)) {
 610                 /* Type indicates this is not an ILA address */
 611                 return 0;
 612         }
 613
 614         rcu_read_lock();
 615
 616         ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
 617         if (ila)
 618                 ila_update_ipv6_locator(skb, &ila->xp.ip, set_csum_neutral);
 619
 620         rcu_read_unlock();
 621
 622         return 0;
 623 }
 624
 625 int ila_xlat_init(void)
 626 {
 627         int ret;
 628
 629         ret = register_pernet_device(&ila_net_ops);
 630         if (ret)
 631                 goto exit;
 632
 633         ret = genl_register_family_with_ops(&ila_nl_family,
 634                                             ila_nl_ops);
 635         if (ret < 0)
 636                 goto unregister;
 637
 638         return 0;
 639
 640 unregister:
 641         unregister_pernet_device(&ila_net_ops);
 642 exit:
 643         return ret;
 644 }
 645
 646 void ila_xlat_fini(void)
 647 {
 648         genl_unregister_family(&ila_nl_family);
 649         unregister_pernet_device(&ila_net_ops);
 650 }