net/ipv6/ila/ila_xlat.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/jhash.h>
   3 #include <linux/netfilter.h>
   4 #include <linux/rcupdate.h>
   5 #include <linux/rhashtable.h>
   6 #include <linux/vmalloc.h>
   7 #include <net/genetlink.h>
   8 #include <net/ila.h>
   9 #include <net/netns/generic.h>
  10 #include <uapi/linux/genetlink.h>
  11 #include "ila.h"
  12
  13 struct ila_xlat_params {
  14         struct ila_params ip;
  15         int ifindex;
  16 };
  17
  18 struct ila_map {
  19         struct ila_xlat_params xp;
  20         struct rhash_head node;
  21         struct ila_map __rcu *next;
  22         struct rcu_head rcu;
  23 };
  24
  25 static unsigned int ila_net_id;
  26
  27 struct ila_net {
  28         struct rhashtable rhash_table;
  29         spinlock_t *locks; /* Bucket locks for entry manipulation */
  30         unsigned int locks_mask;
  31         bool hooks_registered;
  32 };
  33
  34 #define LOCKS_PER_CPU 10
  35
  36 static int alloc_ila_locks(struct ila_net *ilan)
  37 {
  38         unsigned int i, size;
  39         unsigned int nr_pcpus = num_possible_cpus();
  40
  41         nr_pcpus = min_t(unsigned int, nr_pcpus, 32UL);
  42         size = roundup_pow_of_two(nr_pcpus * LOCKS_PER_CPU);
  43
  44         if (sizeof(spinlock_t) != 0) {
  45                 ilan->locks = kvmalloc(size * sizeof(spinlock_t), GFP_KERNEL);
  46                 if (!ilan->locks)
  47                         return -ENOMEM;
  48                 for (i = 0; i < size; i++)
  49                         spin_lock_init(&ilan->locks[i]);
  50         }
  51         ilan->locks_mask = size - 1;
  52
  53         return 0;
  54 }
  55
  56 static u32 hashrnd __read_mostly;
  57 static __always_inline void __ila_hash_secret_init(void)
  58 {
  59         net_get_random_once(&hashrnd, sizeof(hashrnd));
  60 }
  61
  62 static inline u32 ila_locator_hash(struct ila_locator loc)
  63 {
  64         u32 *v = (u32 *)loc.v32;
  65
  66         __ila_hash_secret_init();
  67         return jhash_2words(v[0], v[1], hashrnd);
  68 }
  69
  70 static inline spinlock_t *ila_get_lock(struct ila_net *ilan,
  71                                        struct ila_locator loc)
  72 {
  73         return &ilan->locks[ila_locator_hash(loc) & ilan->locks_mask];
  74 }
  75
  76 static inline int ila_cmp_wildcards(struct ila_map *ila,
  77                                     struct ila_addr *iaddr, int ifindex)
  78 {
  79         return (ila->xp.ifindex && ila->xp.ifindex != ifindex);
  80 }
  81
  82 static inline int ila_cmp_params(struct ila_map *ila,
  83                                  struct ila_xlat_params *xp)
  84 {
  85         return (ila->xp.ifindex != xp->ifindex);
  86 }
  87
  88 static int ila_cmpfn(struct rhashtable_compare_arg *arg,
  89                      const void *obj)
  90 {
  91         const struct ila_map *ila = obj;
  92
  93         return (ila->xp.ip.locator_match.v64 != *(__be64 *)arg->key);
  94 }
  95
  96 static inline int ila_order(struct ila_map *ila)
  97 {
  98         int score = 0;
  99
 100         if (ila->xp.ifindex)
 101                 score += 1 << 1;
 102
 103         return score;
 104 }
 105
 106 static const struct rhashtable_params rht_params = {
 107         .nelem_hint = 1024,
 108         .head_offset = offsetof(struct ila_map, node),
 109         .key_offset = offsetof(struct ila_map, xp.ip.locator_match),
 110         .key_len = sizeof(u64), /* identifier */
 111         .max_size = 1048576,
 112         .min_size = 256,
 113         .automatic_shrinking = true,
 114         .obj_cmpfn = ila_cmpfn,
 115 };
 116
 117 static struct genl_family ila_nl_family;
 118
 119 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 120         [ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 121         [ILA_ATTR_LOCATOR_MATCH] = { .type = NLA_U64, },
 122         [ILA_ATTR_IFINDEX] = { .type = NLA_U32, },
 123         [ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
 124         [ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
 125 };
 126
 127 static int parse_nl_config(struct genl_info *info,
 128                            struct ila_xlat_params *xp)
 129 {
 130         memset(xp, 0, sizeof(*xp));
 131
 132         if (info->attrs[ILA_ATTR_LOCATOR])
 133                 xp->ip.locator.v64 = (__force __be64)nla_get_u64(
 134                         info->attrs[ILA_ATTR_LOCATOR]);
 135
 136         if (info->attrs[ILA_ATTR_LOCATOR_MATCH])
 137                 xp->ip.locator_match.v64 = (__force __be64)nla_get_u64(
 138                         info->attrs[ILA_ATTR_LOCATOR_MATCH]);
 139
 140         if (info->attrs[ILA_ATTR_CSUM_MODE])
 141                 xp->ip.csum_mode = nla_get_u8(info->attrs[ILA_ATTR_CSUM_MODE]);
 142         else
 143                 xp->ip.csum_mode = ILA_CSUM_NO_ACTION;
 144
 145         if (info->attrs[ILA_ATTR_IDENT_TYPE])
 146                 xp->ip.ident_type = nla_get_u8(
 147                                 info->attrs[ILA_ATTR_IDENT_TYPE]);
 148         else
 149                 xp->ip.ident_type = ILA_ATYPE_USE_FORMAT;
 150
 151         if (info->attrs[ILA_ATTR_IFINDEX])
 152                 xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
 153
 154         return 0;
 155 }
 156
 157 /* Must be called with rcu readlock */
 158 static inline struct ila_map *ila_lookup_wildcards(struct ila_addr *iaddr,
 159                                                    int ifindex,
 160                                                    struct ila_net *ilan)
 161 {
 162         struct ila_map *ila;
 163
 164         ila = rhashtable_lookup_fast(&ilan->rhash_table, &iaddr->loc,
 165                                      rht_params);
 166         while (ila) {
 167                 if (!ila_cmp_wildcards(ila, iaddr, ifindex))
 168                         return ila;
 169                 ila = rcu_access_pointer(ila->next);
 170         }
 171
 172         return NULL;
 173 }
 174
 175 /* Must be called with rcu readlock */
 176 static inline struct ila_map *ila_lookup_by_params(struct ila_xlat_params *xp,
 177                                                    struct ila_net *ilan)
 178 {
 179         struct ila_map *ila;
 180
 181         ila = rhashtable_lookup_fast(&ilan->rhash_table,
 182                                      &xp->ip.locator_match,
 183                                      rht_params);
 184         while (ila) {
 185                 if (!ila_cmp_params(ila, xp))
 186                         return ila;
 187                 ila = rcu_access_pointer(ila->next);
 188         }
 189
 190         return NULL;
 191 }
 192
 193 static inline void ila_release(struct ila_map *ila)
 194 {
 195         kfree_rcu(ila, rcu);
 196 }
 197
 198 static void ila_free_cb(void *ptr, void *arg)
 199 {
 200         struct ila_map *ila = (struct ila_map *)ptr, *next;
 201
 202         /* Assume rcu_readlock held */
 203         while (ila) {
 204                 next = rcu_access_pointer(ila->next);
 205                 ila_release(ila);
 206                 ila = next;
 207         }
 208 }
 209
 210 static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila);
 211
 212 static unsigned int
 213 ila_nf_input(void *priv,
 214              struct sk_buff *skb,
 215              const struct nf_hook_state *state)
 216 {
 217         ila_xlat_addr(skb, false);
 218         return NF_ACCEPT;
 219 }
 220
 221 static const struct nf_hook_ops ila_nf_hook_ops[] = {
 222         {
 223                 .hook = ila_nf_input,
 224                 .pf = NFPROTO_IPV6,
 225                 .hooknum = NF_INET_PRE_ROUTING,
 226                 .priority = -1,
 227         },
 228 };
 229
 230 static int ila_add_mapping(struct net *net, struct ila_xlat_params *xp)
 231 {
 232         struct ila_net *ilan = net_generic(net, ila_net_id);
 233         struct ila_map *ila, *head;
 234         spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
 235         int err = 0, order;
 236
 237         if (!ilan->hooks_registered) {
 238                 /* We defer registering net hooks in the namespace until the
 239                  * first mapping is added.
 240                  */
 241                 err = nf_register_net_hooks(net, ila_nf_hook_ops,
 242                                             ARRAY_SIZE(ila_nf_hook_ops));
 243                 if (err)
 244                         return err;
 245
 246                 ilan->hooks_registered = true;
 247         }
 248
 249         ila = kzalloc(sizeof(*ila), GFP_KERNEL);
 250         if (!ila)
 251                 return -ENOMEM;
 252
 253         ila_init_saved_csum(&xp->ip);
 254
 255         ila->xp = *xp;
 256
 257         order = ila_order(ila);
 258
 259         spin_lock(lock);
 260
 261         head = rhashtable_lookup_fast(&ilan->rhash_table,
 262                                       &xp->ip.locator_match,
 263                                       rht_params);
 264         if (!head) {
 265                 /* New entry for the rhash_table */
 266                 err = rhashtable_lookup_insert_fast(&ilan->rhash_table,
 267                                                     &ila->node, rht_params);
 268         } else {
 269                 struct ila_map *tila = head, *prev = NULL;
 270
 271                 do {
 272                         if (!ila_cmp_params(tila, xp)) {
 273                                 err = -EEXIST;
 274                                 goto out;
 275                         }
 276
 277                         if (order > ila_order(tila))
 278                                 break;
 279
 280                         prev = tila;
 281                         tila = rcu_dereference_protected(tila->next,
 282                                 lockdep_is_held(lock));
 283                 } while (tila);
 284
 285                 if (prev) {
 286                         /* Insert in sub list of head */
 287                         RCU_INIT_POINTER(ila->next, tila);
 288                         rcu_assign_pointer(prev->next, ila);
 289                 } else {
 290                         /* Make this ila new head */
 291                         RCU_INIT_POINTER(ila->next, head);
 292                         err = rhashtable_replace_fast(&ilan->rhash_table,
 293                                                       &head->node,
 294                                                       &ila->node, rht_params);
 295                         if (err)
 296                                 goto out;
 297                 }
 298         }
 299
 300 out:
 301         spin_unlock(lock);
 302
 303         if (err)
 304                 kfree(ila);
 305
 306         return err;
 307 }
 308
 309 static int ila_del_mapping(struct net *net, struct ila_xlat_params *xp)
 310 {
 311         struct ila_net *ilan = net_generic(net, ila_net_id);
 312         struct ila_map *ila, *head, *prev;
 313         spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
 314         int err = -ENOENT;
 315
 316         spin_lock(lock);
 317
 318         head = rhashtable_lookup_fast(&ilan->rhash_table,
 319                                       &xp->ip.locator_match, rht_params);
 320         ila = head;
 321
 322         prev = NULL;
 323
 324         while (ila) {
 325                 if (ila_cmp_params(ila, xp)) {
 326                         prev = ila;
 327                         ila = rcu_dereference_protected(ila->next,
 328                                                         lockdep_is_held(lock));
 329                         continue;
 330                 }
 331
 332                 err = 0;
 333
 334                 if (prev) {
 335                         /* Not head, just delete from list */
 336                         rcu_assign_pointer(prev->next, ila->next);
 337                 } else {
 338                         /* It is the head. If there is something in the
 339                          * sublist we need to make a new head.
 340                          */
 341                         head = rcu_dereference_protected(ila->next,
 342                                                          lockdep_is_held(lock));
 343                         if (head) {
 344                                 /* Put first entry in the sublist into the
 345                                  * table
 346                                  */
 347                                 err = rhashtable_replace_fast(
 348                                         &ilan->rhash_table, &ila->node,
 349                                         &head->node, rht_params);
 350                                 if (err)
 351                                         goto out;
 352                         } else {
 353                                 /* Entry no longer used */
 354                                 err = rhashtable_remove_fast(&ilan->rhash_table,
 355                                                              &ila->node,
 356                                                              rht_params);
 357                         }
 358                 }
 359
 360                 ila_release(ila);
 361
 362                 break;
 363         }
 364
 365 out:
 366         spin_unlock(lock);
 367
 368         return err;
 369 }
 370
 371 static int ila_nl_cmd_add_mapping(struct sk_buff *skb, struct genl_info *info)
 372 {
 373         struct net *net = genl_info_net(info);
 374         struct ila_xlat_params p;
 375         int err;
 376
 377         err = parse_nl_config(info, &p);
 378         if (err)
 379                 return err;
 380
 381         return ila_add_mapping(net, &p);
 382 }
 383
 384 static int ila_nl_cmd_del_mapping(struct sk_buff *skb, struct genl_info *info)
 385 {
 386         struct net *net = genl_info_net(info);
 387         struct ila_xlat_params xp;
 388         int err;
 389
 390         err = parse_nl_config(info, &xp);
 391         if (err)
 392                 return err;
 393
 394         ila_del_mapping(net, &xp);
 395
 396         return 0;
 397 }
 398
 399 static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
 400 {
 401         if (nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR,
 402                               (__force u64)ila->xp.ip.locator.v64,
 403                               ILA_ATTR_PAD) ||
 404             nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR_MATCH,
 405                               (__force u64)ila->xp.ip.locator_match.v64,
 406                               ILA_ATTR_PAD) ||
 407             nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
 408             nla_put_u8(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode) ||
 409             nla_put_u8(msg, ILA_ATTR_IDENT_TYPE, ila->xp.ip.ident_type))
 410                 return -1;
 411
 412         return 0;
 413 }
 414
 415 static int ila_dump_info(struct ila_map *ila,
 416                          u32 portid, u32 seq, u32 flags,
 417                          struct sk_buff *skb, u8 cmd)
 418 {
 419         void *hdr;
 420
 421         hdr = genlmsg_put(skb, portid, seq, &ila_nl_family, flags, cmd);
 422         if (!hdr)
 423                 return -ENOMEM;
 424
 425         if (ila_fill_info(ila, skb) < 0)
 426                 goto nla_put_failure;
 427
 428         genlmsg_end(skb, hdr);
 429         return 0;
 430
 431 nla_put_failure:
 432         genlmsg_cancel(skb, hdr);
 433         return -EMSGSIZE;
 434 }
 435
 436 static int ila_nl_cmd_get_mapping(struct sk_buff *skb, struct genl_info *info)
 437 {
 438         struct net *net = genl_info_net(info);
 439         struct ila_net *ilan = net_generic(net, ila_net_id);
 440         struct sk_buff *msg;
 441         struct ila_xlat_params xp;
 442         struct ila_map *ila;
 443         int ret;
 444
 445         ret = parse_nl_config(info, &xp);
 446         if (ret)
 447                 return ret;
 448
 449         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 450         if (!msg)
 451                 return -ENOMEM;
 452
 453         rcu_read_lock();
 454
 455         ila = ila_lookup_by_params(&xp, ilan);
 456         if (ila) {
 457                 ret = ila_dump_info(ila,
 458                                     info->snd_portid,
 459                                     info->snd_seq, 0, msg,
 460                                     info->genlhdr->cmd);
 461         }
 462
 463         rcu_read_unlock();
 464
 465         if (ret < 0)
 466                 goto out_free;
 467
 468         return genlmsg_reply(msg, info);
 469
 470 out_free:
 471         nlmsg_free(msg);
 472         return ret;
 473 }
 474
 475 struct ila_dump_iter {
 476         struct rhashtable_iter rhiter;
 477 };
 478
 479 static int ila_nl_dump_start(struct netlink_callback *cb)
 480 {
 481         struct net *net = sock_net(cb->skb->sk);
 482         struct ila_net *ilan = net_generic(net, ila_net_id);
 483         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
 484
 485         if (!iter) {
 486                 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 487                 if (!iter)
 488                         return -ENOMEM;
 489
 490                 cb->args[0] = (long)iter;
 491         }
 492
 493         return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
 494                                     GFP_KERNEL);
 495 }
 496
 497 static int ila_nl_dump_done(struct netlink_callback *cb)
 498 {
 499         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
 500
 501         rhashtable_walk_exit(&iter->rhiter);
 502
 503         kfree(iter);
 504
 505         return 0;
 506 }
 507
 508 static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
 509 {
 510         struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
 511         struct rhashtable_iter *rhiter = &iter->rhiter;
 512         struct ila_map *ila;
 513         int ret;
 514
 515         rhashtable_walk_start(rhiter);
 516
 517         for (;;) {
 518                 ila = rhashtable_walk_next(rhiter);
 519
 520                 if (IS_ERR(ila)) {
 521                         if (PTR_ERR(ila) == -EAGAIN)
 522                                 continue;
 523                         ret = PTR_ERR(ila);
 524                         goto done;
 525                 } else if (!ila) {
 526                         break;
 527                 }
 528
 529                 while (ila) {
 530                         ret =  ila_dump_info(ila, NETLINK_CB(cb->skb).portid,
 531                                              cb->nlh->nlmsg_seq, NLM_F_MULTI,
 532                                              skb, ILA_CMD_GET);
 533                         if (ret)
 534                                 goto done;
 535
 536                         ila = rcu_access_pointer(ila->next);
 537                 }
 538         }
 539
 540         ret = skb->len;
 541
 542 done:
 543         rhashtable_walk_stop(rhiter);
 544         return ret;
 545 }
 546
 547 static const struct genl_ops ila_nl_ops[] = {
 548         {
 549                 .cmd = ILA_CMD_ADD,
 550                 .doit = ila_nl_cmd_add_mapping,
 551                 .policy = ila_nl_policy,
 552                 .flags = GENL_ADMIN_PERM,
 553         },
 554         {
 555                 .cmd = ILA_CMD_DEL,
 556                 .doit = ila_nl_cmd_del_mapping,
 557                 .policy = ila_nl_policy,
 558                 .flags = GENL_ADMIN_PERM,
 559         },
 560         {
 561                 .cmd = ILA_CMD_GET,
 562                 .doit = ila_nl_cmd_get_mapping,
 563                 .start = ila_nl_dump_start,
 564                 .dumpit = ila_nl_dump,
 565                 .done = ila_nl_dump_done,
 566                 .policy = ila_nl_policy,
 567         },
 568 };
 569
 570 static struct genl_family ila_nl_family __ro_after_init = {
 571         .hdrsize        = 0,
 572         .name           = ILA_GENL_NAME,
 573         .version        = ILA_GENL_VERSION,
 574         .maxattr        = ILA_ATTR_MAX,
 575         .netnsok        = true,
 576         .parallel_ops   = true,
 577         .module         = THIS_MODULE,
 578         .ops            = ila_nl_ops,
 579         .n_ops          = ARRAY_SIZE(ila_nl_ops),
 580 };
 581
 582 #define ILA_HASH_TABLE_SIZE 1024
 583
 584 static __net_init int ila_init_net(struct net *net)
 585 {
 586         int err;
 587         struct ila_net *ilan = net_generic(net, ila_net_id);
 588
 589         err = alloc_ila_locks(ilan);
 590         if (err)
 591                 return err;
 592
 593         rhashtable_init(&ilan->rhash_table, &rht_params);
 594
 595         return 0;
 596 }
 597
 598 static __net_exit void ila_exit_net(struct net *net)
 599 {
 600         struct ila_net *ilan = net_generic(net, ila_net_id);
 601
 602         rhashtable_free_and_destroy(&ilan->rhash_table, ila_free_cb, NULL);
 603
 604         kvfree(ilan->locks);
 605
 606         if (ilan->hooks_registered)
 607                 nf_unregister_net_hooks(net, ila_nf_hook_ops,
 608                                         ARRAY_SIZE(ila_nf_hook_ops));
 609 }
 610
 611 static struct pernet_operations ila_net_ops = {
 612         .init = ila_init_net,
 613         .exit = ila_exit_net,
 614         .id   = &ila_net_id,
 615         .size = sizeof(struct ila_net),
 616 };
 617
 618 static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila)
 619 {
 620         struct ila_map *ila;
 621         struct ipv6hdr *ip6h = ipv6_hdr(skb);
 622         struct net *net = dev_net(skb->dev);
 623         struct ila_net *ilan = net_generic(net, ila_net_id);
 624         struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 625
 626         /* Assumes skb contains a valid IPv6 header that is pulled */
 627
 628         /* No check here that ILA type in the mapping matches what is in the
 629          * address. We assume that whatever sender gaves us can be translated.
 630          * The checksum mode however is relevant.
 631          */
 632
 633         rcu_read_lock();
 634
 635         ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
 636         if (ila)
 637                 ila_update_ipv6_locator(skb, &ila->xp.ip, sir2ila);
 638
 639         rcu_read_unlock();
 640
 641         return 0;
 642 }
 643
 644 int __init ila_xlat_init(void)
 645 {
 646         int ret;
 647
 648         ret = register_pernet_device(&ila_net_ops);
 649         if (ret)
 650                 goto exit;
 651
 652         ret = genl_register_family(&ila_nl_family);
 653         if (ret < 0)
 654                 goto unregister;
 655
 656         return 0;
 657
 658 unregister:
 659         unregister_pernet_device(&ila_net_ops);
 660 exit:
 661         return ret;
 662 }
 663
 664 void ila_xlat_fini(void)
 665 {
 666         genl_unregister_family(&ila_nl_family);
 667         unregister_pernet_device(&ila_net_ops);
 668 }