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         .id             = GENL_ID_GENERATE,
 123         .hdrsize        = 0,
 124         .name           = ILA_GENL_NAME,
 125         .version        = ILA_GENL_VERSION,
 126         .maxattr        = ILA_ATTR_MAX,
 127         .netnsok        = true,
 128         .parallel_ops   = true,
 129 };
 130
 131 static struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 132         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 133         [ILA_ATTR_LOCATOR_MATCH] = { .type = NLA_U64, },
 134         [ILA_ATTR_IFINDEX] = { .type = NLA_U32, },
 135         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 136 };
 137
 138 static int parse_nl_config(struct genl_info *info,
 139                            struct ila_xlat_params *xp)
 140 {
 141         memset(xp, 0, sizeof(*xp));
 142
 143         if (info->attrs[ILA_ATTR_LOCATOR])
 144                 xp->ip.locator.v64 = (__force __be64)nla_get_u64(
 145                         info->attrs[ILA_ATTR_LOCATOR]);
 146
 147         if (info->attrs[ILA_ATTR_LOCATOR_MATCH])
 148                 xp->ip.locator_match.v64 = (__force __be64)nla_get_u64(
 149                         info->attrs[ILA_ATTR_LOCATOR_MATCH]);
 150
 151         if (info->attrs[ILA_ATTR_CSUM_MODE])
 152                 xp->ip.csum_mode = nla_get_u8(info->attrs[ILA_ATTR_CSUM_MODE]);
 153
 154         if (info->attrs[ILA_ATTR_IFINDEX])
 155                 xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
 156
 157         return 0;
 158 }
 159
 160 /* Must be called with rcu readlock */
 161 static inline struct ila_map *ila_lookup_wildcards(struct ila_addr *iaddr,
 162                                                    int ifindex,
 163                                                    struct ila_net *ilan)
 164 {
 165         struct ila_map *ila;
 166
 167         ila = rhashtable_lookup_fast(&ilan->rhash_table, &iaddr->loc,
 168                                      rht_params);
 169         while (ila) {
 170                 if (!ila_cmp_wildcards(ila, iaddr, ifindex))
 171                         return ila;
 172                 ila = rcu_access_pointer(ila->next);
 173         }
 174
 175         return NULL;
 176 }
 177
 178 /* Must be called with rcu readlock */
 179 static inline struct ila_map *ila_lookup_by_params(struct ila_xlat_params *xp,
 180                                                    struct ila_net *ilan)
 181 {
 182         struct ila_map *ila;
 183
 184         ila = rhashtable_lookup_fast(&ilan->rhash_table,
 185                                      &xp->ip.locator_match,
 186                                      rht_params);
 187         while (ila) {
 188                 if (!ila_cmp_params(ila, xp))
 189                         return ila;
 190                 ila = rcu_access_pointer(ila->next);
 191         }
 192
 193         return NULL;
 194 }
 195
 196 static inline void ila_release(struct ila_map *ila)
 197 {
 198         kfree_rcu(ila, rcu);
 199 }
 200
 201 static void ila_free_cb(void *ptr, void *arg)
 202 {
 203         struct ila_map *ila = (struct ila_map *)ptr, *next;
 204
 205         /* Assume rcu_readlock held */
 206         while (ila) {
 207                 next = rcu_access_pointer(ila->next);
 208                 ila_release(ila);
 209                 ila = next;
 210         }
 211 }
 212
 213 static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral);
 214
 215 static unsigned int
 216 ila_nf_input(void *priv,
 217              struct sk_buff *skb,
 218              const struct nf_hook_state *state)
 219 {
 220         ila_xlat_addr(skb, false);
 221         return NF_ACCEPT;
 222 }
 223
 224 static struct nf_hook_ops ila_nf_hook_ops[] __read_mostly = {
 225         {
 226                 .hook = ila_nf_input,
 227                 .pf = NFPROTO_IPV6,
 228                 .hooknum = NF_INET_PRE_ROUTING,
 229                 .priority = -1,
 230         },
 231 };
 232
 233 static int ila_add_mapping(struct net *net, struct ila_xlat_params *xp)
 234 {
 235         struct ila_net *ilan = net_generic(net, ila_net_id);
 236         struct ila_map *ila, *head;
 237         spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
 238         int err = 0, order;
 239
 240         if (!ilan->hooks_registered) {
 241                 /* We defer registering net hooks in the namespace until the
 242                  * first mapping is added.
 243                  */
 244                 err = nf_register_net_hooks(net, ila_nf_hook_ops,
 245                                             ARRAY_SIZE(ila_nf_hook_ops));
 246                 if (err)
 247                         return err;
 248
 249                 ilan->hooks_registered = true;
 250         }
 251
 252         ila = kzalloc(sizeof(*ila), GFP_KERNEL);
 253         if (!ila)
 254                 return -ENOMEM;
 255
 256         ila_init_saved_csum(&xp->ip);
 257
 258         ila->xp = *xp;
 259
 260         order = ila_order(ila);
 261
 262         spin_lock(lock);
 263
 264         head = rhashtable_lookup_fast(&ilan->rhash_table,
 265                                       &xp->ip.locator_match,
 266                                       rht_params);
 267         if (!head) {
 268                 /* New entry for the rhash_table */
 269                 err = rhashtable_lookup_insert_fast(&ilan->rhash_table,
 270                                                     &ila->node, rht_params);
 271         } else {
 272                 struct ila_map *tila = head, *prev = NULL;
 273
 274                 do {
 275                         if (!ila_cmp_params(tila, xp)) {
 276                                 err = -EEXIST;
 277                                 goto out;
 278                         }
 279
 280                         if (order > ila_order(tila))
 281                                 break;
 282
 283                         prev = tila;
 284                         tila = rcu_dereference_protected(tila->next,
 285                                 lockdep_is_held(lock));
 286                 } while (tila);
 287
 288                 if (prev) {
 289                         /* Insert in sub list of head */
 290                         RCU_INIT_POINTER(ila->next, tila);
 291                         rcu_assign_pointer(prev->next, ila);
 292                 } else {
 293                         /* Make this ila new head */
 294                         RCU_INIT_POINTER(ila->next, head);
 295                         err = rhashtable_replace_fast(&ilan->rhash_table,
 296                                                       &head->node,
 297                                                       &ila->node, rht_params);
 298                         if (err)
 299                                 goto out;
 300                 }
 301         }
 302
 303 out:
 304         spin_unlock(lock);
 305
 306         if (err)
 307                 kfree(ila);
 308
 309         return err;
 310 }
 311
 312 static int ila_del_mapping(struct net *net, struct ila_xlat_params *xp)
 313 {
 314         struct ila_net *ilan = net_generic(net, ila_net_id);
 315         struct ila_map *ila, *head, *prev;
 316         spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
 317         int err = -ENOENT;
 318
 319         spin_lock(lock);
 320
 321         head = rhashtable_lookup_fast(&ilan->rhash_table,
 322                                       &xp->ip.locator_match, rht_params);
 323         ila = head;
 324
 325         prev = NULL;
 326
 327         while (ila) {
 328                 if (ila_cmp_params(ila, xp)) {
 329                         prev = ila;
 330                         ila = rcu_dereference_protected(ila->next,
 331                                                         lockdep_is_held(lock));
 332                         continue;
 333                 }
 334
 335                 err = 0;
 336
 337                 if (prev) {
 338                         /* Not head, just delete from list */
 339                         rcu_assign_pointer(prev->next, ila->next);
 340                 } else {
 341                         /* It is the head. If there is something in the
 342                          * sublist we need to make a new head.
 343                          */
 344                         head = rcu_dereference_protected(ila->next,
 345                                                          lockdep_is_held(lock));
 346                         if (head) {
 347                                 /* Put first entry in the sublist into the
 348                                  * table
 349                                  */
 350                                 err = rhashtable_replace_fast(
 351                                         &ilan->rhash_table, &ila->node,
 352                                         &head->node, rht_params);
 353                                 if (err)
 354                                         goto out;
 355                         } else {
 356                                 /* Entry no longer used */
 357                                 err = rhashtable_remove_fast(&ilan->rhash_table,
 358                                                              &ila->node,
 359                                                              rht_params);
 360                         }
 361                 }
 362
 363                 ila_release(ila);
 364
 365                 break;
 366         }
 367
 368 out:
 369         spin_unlock(lock);
 370
 371         return err;
 372 }
 373
 374 static int ila_nl_cmd_add_mapping(struct sk_buff *skb, struct genl_info *info)
 375 {
 376         struct net *net = genl_info_net(info);
 377         struct ila_xlat_params p;
 378         int err;
 379
 380         err = parse_nl_config(info, &p);
 381         if (err)
 382                 return err;
 383
 384         return ila_add_mapping(net, &p);
 385 }
 386
 387 static int ila_nl_cmd_del_mapping(struct sk_buff *skb, struct genl_info *info)
 388 {
 389         struct net *net = genl_info_net(info);
 390         struct ila_xlat_params xp;
 391         int err;
 392
 393         err = parse_nl_config(info, &xp);
 394         if (err)
 395                 return err;
 396
 397         ila_del_mapping(net, &xp);
 398
 399         return 0;
 400 }
 401
 402 static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
 403 {
 404         if (nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR,
 405                               (__force u64)ila->xp.ip.locator.v64,
 406                               ILA_ATTR_PAD) ||
 407             nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR_MATCH,
 408                               (__force u64)ila->xp.ip.locator_match.v64,
 409                               ILA_ATTR_PAD) ||
 410             nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
 411             nla_put_u32(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode))
 412                 return -1;
 413
 414         return 0;
 415 }
 416
 417 static int ila_dump_info(struct ila_map *ila,
 418                          u32 portid, u32 seq, u32 flags,
 419                          struct sk_buff *skb, u8 cmd)
 420 {
 421         void *hdr;
 422
 423         hdr = genlmsg_put(skb, portid, seq, &ila_nl_family, flags, cmd);
 424         if (!hdr)
 425                 return -ENOMEM;
 426
 427         if (ila_fill_info(ila, skb) < 0)
 428                 goto nla_put_failure;
 429
 430         genlmsg_end(skb, hdr);
 431         return 0;
 432
 433 nla_put_failure:
 434         genlmsg_cancel(skb, hdr);
 435         return -EMSGSIZE;
 436 }
 437
 438 static int ila_nl_cmd_get_mapping(struct sk_buff *skb, struct genl_info *info)
 439 {
 440         struct net *net = genl_info_net(info);
 441         struct ila_net *ilan = net_generic(net, ila_net_id);
 442         struct sk_buff *msg;
 443         struct ila_xlat_params xp;
 444         struct ila_map *ila;
 445         int ret;
 446
 447         ret = parse_nl_config(info, &xp);
 448         if (ret)
 449                 return ret;
 450
 451         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 452         if (!msg)
 453                 return -ENOMEM;
 454
 455         rcu_read_lock();
 456
 457         ila = ila_lookup_by_params(&xp, ilan);
 458         if (ila) {
 459                 ret = ila_dump_info(ila,
 460                                     info->snd_portid,
 461                                     info->snd_seq, 0, msg,
 462                                     info->genlhdr->cmd);
 463         }
 464
 465         rcu_read_unlock();
 466
 467         if (ret < 0)
 468                 goto out_free;
 469
 470         return genlmsg_reply(msg, info);
 471
 472 out_free:
 473         nlmsg_free(msg);
 474         return ret;
 475 }
 476
 477 struct ila_dump_iter {
 478         struct rhashtable_iter rhiter;
 479 };
 480
 481 static int ila_nl_dump_start(struct netlink_callback *cb)
 482 {
 483         struct net *net = sock_net(cb->skb->sk);
 484         struct ila_net *ilan = net_generic(net, ila_net_id);
 485         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 486
 487         return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
 488                                     GFP_KERNEL);
 489 }
 490
 491 static int ila_nl_dump_done(struct netlink_callback *cb)
 492 {
 493         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 494
 495         rhashtable_walk_exit(&iter->rhiter);
 496
 497         return 0;
 498 }
 499
 500 static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 501 {
 502         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
 503         struct rhashtable_iter *rhiter = &iter->rhiter;
 504         struct ila_map *ila;
 505         int ret;
 506
 507         ret = rhashtable_walk_start(rhiter);
 508         if (ret && ret != -EAGAIN)
 509                 goto done;
 510
 511         for (;;) {
 512                 ila = rhashtable_walk_next(rhiter);
 513
 514                 if (IS_ERR(ila)) {
 515                         if (PTR_ERR(ila) == -EAGAIN)
 516                                 continue;
 517                         ret = PTR_ERR(ila);
 518                         goto done;
 519                 } else if (!ila) {
 520                         break;
 521                 }
 522
 523                 while (ila) {
 524                         ret =  ila_dump_info(ila, NETLINK_CB(cb->skb).portid,
 525                                              cb->nlh->nlmsg_seq, NLM_F_MULTI,
 526                                              skb, ILA_CMD_GET);
 527                         if (ret)
 528                                 goto done;
 529
 530                         ila = rcu_access_pointer(ila->next);
 531                 }
 532         }
 533
 534         ret = skb->len;
 535
 536 done:
 537         rhashtable_walk_stop(rhiter);
 538         return ret;
 539 }
 540
 541 static const struct genl_ops ila_nl_ops[] = {
 542         {
 543                 .cmd = ILA_CMD_ADD,
 544                 .doit = ila_nl_cmd_add_mapping,
 545                 .policy = ila_nl_policy,
 546                 .flags = GENL_ADMIN_PERM,
 547         },
 548         {
 549                 .cmd = ILA_CMD_DEL,
 550                 .doit = ila_nl_cmd_del_mapping,
 551                 .policy = ila_nl_policy,
 552                 .flags = GENL_ADMIN_PERM,
 553         },
 554         {
 555                 .cmd = ILA_CMD_GET,
 556                 .doit = ila_nl_cmd_get_mapping,
 557                 .start = ila_nl_dump_start,
 558                 .dumpit = ila_nl_dump,
 559                 .done = ila_nl_dump_done,
 560                 .policy = ila_nl_policy,
 561         },
 562 };
 563
 564 #define ILA_HASH_TABLE_SIZE 1024
 565
 566 static __net_init int ila_init_net(struct net *net)
 567 {
 568         int err;
 569         struct ila_net *ilan = net_generic(net, ila_net_id);
 570
 571         err = alloc_ila_locks(ilan);
 572         if (err)
 573                 return err;
 574
 575         rhashtable_init(&ilan->rhash_table, &rht_params);
 576
 577         return 0;
 578 }
 579
 580 static __net_exit void ila_exit_net(struct net *net)
 581 {
 582         struct ila_net *ilan = net_generic(net, ila_net_id);
 583
 584         rhashtable_free_and_destroy(&ilan->rhash_table, ila_free_cb, NULL);
 585
 586         kvfree(ilan->locks);
 587
 588         if (ilan->hooks_registered)
 589                 nf_unregister_net_hooks(net, ila_nf_hook_ops,
 590                                         ARRAY_SIZE(ila_nf_hook_ops));
 591 }
 592
 593 static struct pernet_operations ila_net_ops = {
 594         .init = ila_init_net,
 595         .exit = ila_exit_net,
 596         .id   = &ila_net_id,
 597         .size = sizeof(struct ila_net),
 598 };
 599
 600 static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral)
 601 {
 602         struct ila_map *ila;
 603         struct ipv6hdr *ip6h = ipv6_hdr(skb);
 604         struct net *net = dev_net(skb->dev);
 605         struct ila_net *ilan = net_generic(net, ila_net_id);
 606         struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 607
 608         /* Assumes skb contains a valid IPv6 header that is pulled */
 609
 610         if (!ila_addr_is_ila(iaddr)) {
 611                 /* Type indicates this is not an ILA address */
 612                 return 0;
 613         }
 614
 615         rcu_read_lock();
 616
 617         ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
 618         if (ila)
 619                 ila_update_ipv6_locator(skb, &ila->xp.ip, set_csum_neutral);
 620
 621         rcu_read_unlock();
 622
 623         return 0;
 624 }
 625
 626 int ila_xlat_init(void)
 627 {
 628         int ret;
 629
 630         ret = register_pernet_device(&ila_net_ops);
 631         if (ret)
 632                 goto exit;
 633
 634         ret = genl_register_family_with_ops(&ila_nl_family,
 635                                             ila_nl_ops);
 636         if (ret < 0)
 637                 goto unregister;
 638
 639         return 0;
 640
 641 unregister:
 642         unregister_pernet_device(&ila_net_ops);
 643 exit:
 644         return ret;
 645 }
 646
 647 void ila_xlat_fini(void)
 648 {
 649         genl_unregister_family(&ila_nl_family);
 650         unregister_pernet_device(&ila_net_ops);
 651 }