linux/net/netlabel/netlabel_domainhash.c
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   1/*
   2 * NetLabel Domain Hash Table
   3 *
   4 * This file manages the domain hash table that NetLabel uses to determine
   5 * which network labeling protocol to use for a given domain.  The NetLabel
   6 * system manages static and dynamic label mappings for network protocols such
   7 * as CIPSO and RIPSO.
   8 *
   9 * Author: Paul Moore <paul@paul-moore.com>
  10 *
  11 */
  12
  13/*
  14 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
  15 *
  16 * This program is free software;  you can redistribute it and/or modify
  17 * it under the terms of the GNU General Public License as published by
  18 * the Free Software Foundation; either version 2 of the License, or
  19 * (at your option) any later version.
  20 *
  21 * This program is distributed in the hope that it will be useful,
  22 * but WITHOUT ANY WARRANTY;  without even the implied warranty of
  23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  24 * the GNU General Public License for more details.
  25 *
  26 * You should have received a copy of the GNU General Public License
  27 * along with this program;  if not, write to the Free Software
  28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  29 *
  30 */
  31
  32#include <linux/types.h>
  33#include <linux/rculist.h>
  34#include <linux/skbuff.h>
  35#include <linux/spinlock.h>
  36#include <linux/string.h>
  37#include <linux/audit.h>
  38#include <linux/slab.h>
  39#include <net/netlabel.h>
  40#include <net/cipso_ipv4.h>
  41#include <asm/bug.h>
  42
  43#include "netlabel_mgmt.h"
  44#include "netlabel_addrlist.h"
  45#include "netlabel_domainhash.h"
  46#include "netlabel_user.h"
  47
  48struct netlbl_domhsh_tbl {
  49        struct list_head *tbl;
  50        u32 size;
  51};
  52
  53/* Domain hash table */
  54/* updates should be so rare that having one spinlock for the entire hash table
  55 * should be okay */
  56static DEFINE_SPINLOCK(netlbl_domhsh_lock);
  57#define netlbl_domhsh_rcu_deref(p) \
  58        rcu_dereference_check(p, lockdep_is_held(&netlbl_domhsh_lock))
  59static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
  60static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
  61
  62/*
  63 * Domain Hash Table Helper Functions
  64 */
  65
  66/**
  67 * netlbl_domhsh_free_entry - Frees a domain hash table entry
  68 * @entry: the entry's RCU field
  69 *
  70 * Description:
  71 * This function is designed to be used as a callback to the call_rcu()
  72 * function so that the memory allocated to a hash table entry can be released
  73 * safely.
  74 *
  75 */
  76static void netlbl_domhsh_free_entry(struct rcu_head *entry)
  77{
  78        struct netlbl_dom_map *ptr;
  79        struct netlbl_af4list *iter4;
  80        struct netlbl_af4list *tmp4;
  81#if IS_ENABLED(CONFIG_IPV6)
  82        struct netlbl_af6list *iter6;
  83        struct netlbl_af6list *tmp6;
  84#endif /* IPv6 */
  85
  86        ptr = container_of(entry, struct netlbl_dom_map, rcu);
  87        if (ptr->type == NETLBL_NLTYPE_ADDRSELECT) {
  88                netlbl_af4list_foreach_safe(iter4, tmp4,
  89                                            &ptr->type_def.addrsel->list4) {
  90                        netlbl_af4list_remove_entry(iter4);
  91                        kfree(netlbl_domhsh_addr4_entry(iter4));
  92                }
  93#if IS_ENABLED(CONFIG_IPV6)
  94                netlbl_af6list_foreach_safe(iter6, tmp6,
  95                                            &ptr->type_def.addrsel->list6) {
  96                        netlbl_af6list_remove_entry(iter6);
  97                        kfree(netlbl_domhsh_addr6_entry(iter6));
  98                }
  99#endif /* IPv6 */
 100        }
 101        kfree(ptr->domain);
 102        kfree(ptr);
 103}
 104
 105/**
 106 * netlbl_domhsh_hash - Hashing function for the domain hash table
 107 * @domain: the domain name to hash
 108 *
 109 * Description:
 110 * This is the hashing function for the domain hash table, it returns the
 111 * correct bucket number for the domain.  The caller is responsible for
 112 * ensuring that the hash table is protected with either a RCU read lock or the
 113 * hash table lock.
 114 *
 115 */
 116static u32 netlbl_domhsh_hash(const char *key)
 117{
 118        u32 iter;
 119        u32 val;
 120        u32 len;
 121
 122        /* This is taken (with slight modification) from
 123         * security/selinux/ss/symtab.c:symhash() */
 124
 125        for (iter = 0, val = 0, len = strlen(key); iter < len; iter++)
 126                val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter];
 127        return val & (netlbl_domhsh_rcu_deref(netlbl_domhsh)->size - 1);
 128}
 129
 130/**
 131 * netlbl_domhsh_search - Search for a domain entry
 132 * @domain: the domain
 133 *
 134 * Description:
 135 * Searches the domain hash table and returns a pointer to the hash table
 136 * entry if found, otherwise NULL is returned.  The caller is responsible for
 137 * ensuring that the hash table is protected with either a RCU read lock or the
 138 * hash table lock.
 139 *
 140 */
 141static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain)
 142{
 143        u32 bkt;
 144        struct list_head *bkt_list;
 145        struct netlbl_dom_map *iter;
 146
 147        if (domain != NULL) {
 148                bkt = netlbl_domhsh_hash(domain);
 149                bkt_list = &netlbl_domhsh_rcu_deref(netlbl_domhsh)->tbl[bkt];
 150                list_for_each_entry_rcu(iter, bkt_list, list)
 151                        if (iter->valid && strcmp(iter->domain, domain) == 0)
 152                                return iter;
 153        }
 154
 155        return NULL;
 156}
 157
 158/**
 159 * netlbl_domhsh_search_def - Search for a domain entry
 160 * @domain: the domain
 161 * @def: return default if no match is found
 162 *
 163 * Description:
 164 * Searches the domain hash table and returns a pointer to the hash table
 165 * entry if an exact match is found, if an exact match is not present in the
 166 * hash table then the default entry is returned if valid otherwise NULL is
 167 * returned.  The caller is responsible ensuring that the hash table is
 168 * protected with either a RCU read lock or the hash table lock.
 169 *
 170 */
 171static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain)
 172{
 173        struct netlbl_dom_map *entry;
 174
 175        entry = netlbl_domhsh_search(domain);
 176        if (entry == NULL) {
 177                entry = netlbl_domhsh_rcu_deref(netlbl_domhsh_def);
 178                if (entry != NULL && !entry->valid)
 179                        entry = NULL;
 180        }
 181
 182        return entry;
 183}
 184
 185/**
 186 * netlbl_domhsh_audit_add - Generate an audit entry for an add event
 187 * @entry: the entry being added
 188 * @addr4: the IPv4 address information
 189 * @addr6: the IPv6 address information
 190 * @result: the result code
 191 * @audit_info: NetLabel audit information
 192 *
 193 * Description:
 194 * Generate an audit record for adding a new NetLabel/LSM mapping entry with
 195 * the given information.  Caller is responsible for holding the necessary
 196 * locks.
 197 *
 198 */
 199static void netlbl_domhsh_audit_add(struct netlbl_dom_map *entry,
 200                                    struct netlbl_af4list *addr4,
 201                                    struct netlbl_af6list *addr6,
 202                                    int result,
 203                                    struct netlbl_audit *audit_info)
 204{
 205        struct audit_buffer *audit_buf;
 206        struct cipso_v4_doi *cipsov4 = NULL;
 207        u32 type;
 208
 209        audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info);
 210        if (audit_buf != NULL) {
 211                audit_log_format(audit_buf, " nlbl_domain=%s",
 212                                 entry->domain ? entry->domain : "(default)");
 213                if (addr4 != NULL) {
 214                        struct netlbl_domaddr4_map *map4;
 215                        map4 = netlbl_domhsh_addr4_entry(addr4);
 216                        type = map4->type;
 217                        cipsov4 = map4->type_def.cipsov4;
 218                        netlbl_af4list_audit_addr(audit_buf, 0, NULL,
 219                                                  addr4->addr, addr4->mask);
 220#if IS_ENABLED(CONFIG_IPV6)
 221                } else if (addr6 != NULL) {
 222                        struct netlbl_domaddr6_map *map6;
 223                        map6 = netlbl_domhsh_addr6_entry(addr6);
 224                        type = map6->type;
 225                        netlbl_af6list_audit_addr(audit_buf, 0, NULL,
 226                                                  &addr6->addr, &addr6->mask);
 227#endif /* IPv6 */
 228                } else {
 229                        type = entry->type;
 230                        cipsov4 = entry->type_def.cipsov4;
 231                }
 232                switch (type) {
 233                case NETLBL_NLTYPE_UNLABELED:
 234                        audit_log_format(audit_buf, " nlbl_protocol=unlbl");
 235                        break;
 236                case NETLBL_NLTYPE_CIPSOV4:
 237                        BUG_ON(cipsov4 == NULL);
 238                        audit_log_format(audit_buf,
 239                                         " nlbl_protocol=cipsov4 cipso_doi=%u",
 240                                         cipsov4->doi);
 241                        break;
 242                }
 243                audit_log_format(audit_buf, " res=%u", result == 0 ? 1 : 0);
 244                audit_log_end(audit_buf);
 245        }
 246}
 247
 248/*
 249 * Domain Hash Table Functions
 250 */
 251
 252/**
 253 * netlbl_domhsh_init - Init for the domain hash
 254 * @size: the number of bits to use for the hash buckets
 255 *
 256 * Description:
 257 * Initializes the domain hash table, should be called only by
 258 * netlbl_user_init() during initialization.  Returns zero on success, non-zero
 259 * values on error.
 260 *
 261 */
 262int __init netlbl_domhsh_init(u32 size)
 263{
 264        u32 iter;
 265        struct netlbl_domhsh_tbl *hsh_tbl;
 266
 267        if (size == 0)
 268                return -EINVAL;
 269
 270        hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL);
 271        if (hsh_tbl == NULL)
 272                return -ENOMEM;
 273        hsh_tbl->size = 1 << size;
 274        hsh_tbl->tbl = kcalloc(hsh_tbl->size,
 275                               sizeof(struct list_head),
 276                               GFP_KERNEL);
 277        if (hsh_tbl->tbl == NULL) {
 278                kfree(hsh_tbl);
 279                return -ENOMEM;
 280        }
 281        for (iter = 0; iter < hsh_tbl->size; iter++)
 282                INIT_LIST_HEAD(&hsh_tbl->tbl[iter]);
 283
 284        spin_lock(&netlbl_domhsh_lock);
 285        rcu_assign_pointer(netlbl_domhsh, hsh_tbl);
 286        spin_unlock(&netlbl_domhsh_lock);
 287
 288        return 0;
 289}
 290
 291/**
 292 * netlbl_domhsh_add - Adds a entry to the domain hash table
 293 * @entry: the entry to add
 294 * @audit_info: NetLabel audit information
 295 *
 296 * Description:
 297 * Adds a new entry to the domain hash table and handles any updates to the
 298 * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 299 * negative on failure.
 300 *
 301 */
 302int netlbl_domhsh_add(struct netlbl_dom_map *entry,
 303                      struct netlbl_audit *audit_info)
 304{
 305        int ret_val = 0;
 306        struct netlbl_dom_map *entry_old;
 307        struct netlbl_af4list *iter4;
 308        struct netlbl_af4list *tmp4;
 309#if IS_ENABLED(CONFIG_IPV6)
 310        struct netlbl_af6list *iter6;
 311        struct netlbl_af6list *tmp6;
 312#endif /* IPv6 */
 313
 314        /* XXX - we can remove this RCU read lock as the spinlock protects the
 315         *       entire function, but before we do we need to fixup the
 316         *       netlbl_af[4,6]list RCU functions to do "the right thing" with
 317         *       respect to rcu_dereference() when only a spinlock is held. */
 318        rcu_read_lock();
 319        spin_lock(&netlbl_domhsh_lock);
 320        if (entry->domain != NULL)
 321                entry_old = netlbl_domhsh_search(entry->domain);
 322        else
 323                entry_old = netlbl_domhsh_search_def(entry->domain);
 324        if (entry_old == NULL) {
 325                entry->valid = 1;
 326
 327                if (entry->domain != NULL) {
 328                        u32 bkt = netlbl_domhsh_hash(entry->domain);
 329                        list_add_tail_rcu(&entry->list,
 330                                    &rcu_dereference(netlbl_domhsh)->tbl[bkt]);
 331                } else {
 332                        INIT_LIST_HEAD(&entry->list);
 333                        rcu_assign_pointer(netlbl_domhsh_def, entry);
 334                }
 335
 336                if (entry->type == NETLBL_NLTYPE_ADDRSELECT) {
 337                        netlbl_af4list_foreach_rcu(iter4,
 338                                               &entry->type_def.addrsel->list4)
 339                                netlbl_domhsh_audit_add(entry, iter4, NULL,
 340                                                        ret_val, audit_info);
 341#if IS_ENABLED(CONFIG_IPV6)
 342                        netlbl_af6list_foreach_rcu(iter6,
 343                                               &entry->type_def.addrsel->list6)
 344                                netlbl_domhsh_audit_add(entry, NULL, iter6,
 345                                                        ret_val, audit_info);
 346#endif /* IPv6 */
 347                } else
 348                        netlbl_domhsh_audit_add(entry, NULL, NULL,
 349                                                ret_val, audit_info);
 350        } else if (entry_old->type == NETLBL_NLTYPE_ADDRSELECT &&
 351                   entry->type == NETLBL_NLTYPE_ADDRSELECT) {
 352                struct list_head *old_list4;
 353                struct list_head *old_list6;
 354
 355                old_list4 = &entry_old->type_def.addrsel->list4;
 356                old_list6 = &entry_old->type_def.addrsel->list6;
 357
 358                /* we only allow the addition of address selectors if all of
 359                 * the selectors do not exist in the existing domain map */
 360                netlbl_af4list_foreach_rcu(iter4,
 361                                           &entry->type_def.addrsel->list4)
 362                        if (netlbl_af4list_search_exact(iter4->addr,
 363                                                        iter4->mask,
 364                                                        old_list4)) {
 365                                ret_val = -EEXIST;
 366                                goto add_return;
 367                        }
 368#if IS_ENABLED(CONFIG_IPV6)
 369                netlbl_af6list_foreach_rcu(iter6,
 370                                           &entry->type_def.addrsel->list6)
 371                        if (netlbl_af6list_search_exact(&iter6->addr,
 372                                                        &iter6->mask,
 373                                                        old_list6)) {
 374                                ret_val = -EEXIST;
 375                                goto add_return;
 376                        }
 377#endif /* IPv6 */
 378
 379                netlbl_af4list_foreach_safe(iter4, tmp4,
 380                                            &entry->type_def.addrsel->list4) {
 381                        netlbl_af4list_remove_entry(iter4);
 382                        iter4->valid = 1;
 383                        ret_val = netlbl_af4list_add(iter4, old_list4);
 384                        netlbl_domhsh_audit_add(entry_old, iter4, NULL,
 385                                                ret_val, audit_info);
 386                        if (ret_val != 0)
 387                                goto add_return;
 388                }
 389#if IS_ENABLED(CONFIG_IPV6)
 390                netlbl_af6list_foreach_safe(iter6, tmp6,
 391                                            &entry->type_def.addrsel->list6) {
 392                        netlbl_af6list_remove_entry(iter6);
 393                        iter6->valid = 1;
 394                        ret_val = netlbl_af6list_add(iter6, old_list6);
 395                        netlbl_domhsh_audit_add(entry_old, NULL, iter6,
 396                                                ret_val, audit_info);
 397                        if (ret_val != 0)
 398                                goto add_return;
 399                }
 400#endif /* IPv6 */
 401        } else
 402                ret_val = -EINVAL;
 403
 404add_return:
 405        spin_unlock(&netlbl_domhsh_lock);
 406        rcu_read_unlock();
 407        return ret_val;
 408}
 409
 410/**
 411 * netlbl_domhsh_add_default - Adds the default entry to the domain hash table
 412 * @entry: the entry to add
 413 * @audit_info: NetLabel audit information
 414 *
 415 * Description:
 416 * Adds a new default entry to the domain hash table and handles any updates
 417 * to the lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 418 * negative on failure.
 419 *
 420 */
 421int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
 422                              struct netlbl_audit *audit_info)
 423{
 424        return netlbl_domhsh_add(entry, audit_info);
 425}
 426
 427/**
 428 * netlbl_domhsh_remove_entry - Removes a given entry from the domain table
 429 * @entry: the entry to remove
 430 * @audit_info: NetLabel audit information
 431 *
 432 * Description:
 433 * Removes an entry from the domain hash table and handles any updates to the
 434 * lower level protocol handler (i.e. CIPSO).  Caller is responsible for
 435 * ensuring that the RCU read lock is held.  Returns zero on success, negative
 436 * on failure.
 437 *
 438 */
 439int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
 440                               struct netlbl_audit *audit_info)
 441{
 442        int ret_val = 0;
 443        struct audit_buffer *audit_buf;
 444
 445        if (entry == NULL)
 446                return -ENOENT;
 447
 448        spin_lock(&netlbl_domhsh_lock);
 449        if (entry->valid) {
 450                entry->valid = 0;
 451                if (entry != rcu_dereference(netlbl_domhsh_def))
 452                        list_del_rcu(&entry->list);
 453                else
 454                        RCU_INIT_POINTER(netlbl_domhsh_def, NULL);
 455        } else
 456                ret_val = -ENOENT;
 457        spin_unlock(&netlbl_domhsh_lock);
 458
 459        audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
 460        if (audit_buf != NULL) {
 461                audit_log_format(audit_buf,
 462                                 " nlbl_domain=%s res=%u",
 463                                 entry->domain ? entry->domain : "(default)",
 464                                 ret_val == 0 ? 1 : 0);
 465                audit_log_end(audit_buf);
 466        }
 467
 468        if (ret_val == 0) {
 469                struct netlbl_af4list *iter4;
 470                struct netlbl_domaddr4_map *map4;
 471
 472                switch (entry->type) {
 473                case NETLBL_NLTYPE_ADDRSELECT:
 474                        netlbl_af4list_foreach_rcu(iter4,
 475                                             &entry->type_def.addrsel->list4) {
 476                                map4 = netlbl_domhsh_addr4_entry(iter4);
 477                                cipso_v4_doi_putdef(map4->type_def.cipsov4);
 478                        }
 479                        /* no need to check the IPv6 list since we currently
 480                         * support only unlabeled protocols for IPv6 */
 481                        break;
 482                case NETLBL_NLTYPE_CIPSOV4:
 483                        cipso_v4_doi_putdef(entry->type_def.cipsov4);
 484                        break;
 485                }
 486                call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
 487        }
 488
 489        return ret_val;
 490}
 491
 492/**
 493 * netlbl_domhsh_remove_af4 - Removes an address selector entry
 494 * @domain: the domain
 495 * @addr: IPv4 address
 496 * @mask: IPv4 address mask
 497 * @audit_info: NetLabel audit information
 498 *
 499 * Description:
 500 * Removes an individual address selector from a domain mapping and potentially
 501 * the entire mapping if it is empty.  Returns zero on success, negative values
 502 * on failure.
 503 *
 504 */
 505int netlbl_domhsh_remove_af4(const char *domain,
 506                             const struct in_addr *addr,
 507                             const struct in_addr *mask,
 508                             struct netlbl_audit *audit_info)
 509{
 510        struct netlbl_dom_map *entry_map;
 511        struct netlbl_af4list *entry_addr;
 512        struct netlbl_af4list *iter4;
 513#if IS_ENABLED(CONFIG_IPV6)
 514        struct netlbl_af6list *iter6;
 515#endif /* IPv6 */
 516        struct netlbl_domaddr4_map *entry;
 517
 518        rcu_read_lock();
 519
 520        if (domain)
 521                entry_map = netlbl_domhsh_search(domain);
 522        else
 523                entry_map = netlbl_domhsh_search_def(domain);
 524        if (entry_map == NULL || entry_map->type != NETLBL_NLTYPE_ADDRSELECT)
 525                goto remove_af4_failure;
 526
 527        spin_lock(&netlbl_domhsh_lock);
 528        entry_addr = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
 529                                           &entry_map->type_def.addrsel->list4);
 530        spin_unlock(&netlbl_domhsh_lock);
 531
 532        if (entry_addr == NULL)
 533                goto remove_af4_failure;
 534        netlbl_af4list_foreach_rcu(iter4, &entry_map->type_def.addrsel->list4)
 535                goto remove_af4_single_addr;
 536#if IS_ENABLED(CONFIG_IPV6)
 537        netlbl_af6list_foreach_rcu(iter6, &entry_map->type_def.addrsel->list6)
 538                goto remove_af4_single_addr;
 539#endif /* IPv6 */
 540        /* the domain mapping is empty so remove it from the mapping table */
 541        netlbl_domhsh_remove_entry(entry_map, audit_info);
 542
 543remove_af4_single_addr:
 544        rcu_read_unlock();
 545        /* yick, we can't use call_rcu here because we don't have a rcu head
 546         * pointer but hopefully this should be a rare case so the pause
 547         * shouldn't be a problem */
 548        synchronize_rcu();
 549        entry = netlbl_domhsh_addr4_entry(entry_addr);
 550        cipso_v4_doi_putdef(entry->type_def.cipsov4);
 551        kfree(entry);
 552        return 0;
 553
 554remove_af4_failure:
 555        rcu_read_unlock();
 556        return -ENOENT;
 557}
 558
 559/**
 560 * netlbl_domhsh_remove - Removes an entry from the domain hash table
 561 * @domain: the domain to remove
 562 * @audit_info: NetLabel audit information
 563 *
 564 * Description:
 565 * Removes an entry from the domain hash table and handles any updates to the
 566 * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 567 * negative on failure.
 568 *
 569 */
 570int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
 571{
 572        int ret_val;
 573        struct netlbl_dom_map *entry;
 574
 575        rcu_read_lock();
 576        if (domain)
 577                entry = netlbl_domhsh_search(domain);
 578        else
 579                entry = netlbl_domhsh_search_def(domain);
 580        ret_val = netlbl_domhsh_remove_entry(entry, audit_info);
 581        rcu_read_unlock();
 582
 583        return ret_val;
 584}
 585
 586/**
 587 * netlbl_domhsh_remove_default - Removes the default entry from the table
 588 * @audit_info: NetLabel audit information
 589 *
 590 * Description:
 591 * Removes/resets the default entry for the domain hash table and handles any
 592 * updates to the lower level protocol handler (i.e. CIPSO).  Returns zero on
 593 * success, non-zero on failure.
 594 *
 595 */
 596int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info)
 597{
 598        return netlbl_domhsh_remove(NULL, audit_info);
 599}
 600
 601/**
 602 * netlbl_domhsh_getentry - Get an entry from the domain hash table
 603 * @domain: the domain name to search for
 604 *
 605 * Description:
 606 * Look through the domain hash table searching for an entry to match @domain,
 607 * return a pointer to a copy of the entry or NULL.  The caller is responsible
 608 * for ensuring that rcu_read_[un]lock() is called.
 609 *
 610 */
 611struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain)
 612{
 613        return netlbl_domhsh_search_def(domain);
 614}
 615
 616/**
 617 * netlbl_domhsh_getentry_af4 - Get an entry from the domain hash table
 618 * @domain: the domain name to search for
 619 * @addr: the IP address to search for
 620 *
 621 * Description:
 622 * Look through the domain hash table searching for an entry to match @domain
 623 * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
 624 * responsible for ensuring that rcu_read_[un]lock() is called.
 625 *
 626 */
 627struct netlbl_domaddr4_map *netlbl_domhsh_getentry_af4(const char *domain,
 628                                                       __be32 addr)
 629{
 630        struct netlbl_dom_map *dom_iter;
 631        struct netlbl_af4list *addr_iter;
 632
 633        dom_iter = netlbl_domhsh_search_def(domain);
 634        if (dom_iter == NULL)
 635                return NULL;
 636        if (dom_iter->type != NETLBL_NLTYPE_ADDRSELECT)
 637                return NULL;
 638
 639        addr_iter = netlbl_af4list_search(addr,
 640                                          &dom_iter->type_def.addrsel->list4);
 641        if (addr_iter == NULL)
 642                return NULL;
 643
 644        return netlbl_domhsh_addr4_entry(addr_iter);
 645}
 646
 647#if IS_ENABLED(CONFIG_IPV6)
 648/**
 649 * netlbl_domhsh_getentry_af6 - Get an entry from the domain hash table
 650 * @domain: the domain name to search for
 651 * @addr: the IP address to search for
 652 *
 653 * Description:
 654 * Look through the domain hash table searching for an entry to match @domain
 655 * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
 656 * responsible for ensuring that rcu_read_[un]lock() is called.
 657 *
 658 */
 659struct netlbl_domaddr6_map *netlbl_domhsh_getentry_af6(const char *domain,
 660                                                   const struct in6_addr *addr)
 661{
 662        struct netlbl_dom_map *dom_iter;
 663        struct netlbl_af6list *addr_iter;
 664
 665        dom_iter = netlbl_domhsh_search_def(domain);
 666        if (dom_iter == NULL)
 667                return NULL;
 668        if (dom_iter->type != NETLBL_NLTYPE_ADDRSELECT)
 669                return NULL;
 670
 671        addr_iter = netlbl_af6list_search(addr,
 672                                          &dom_iter->type_def.addrsel->list6);
 673        if (addr_iter == NULL)
 674                return NULL;
 675
 676        return netlbl_domhsh_addr6_entry(addr_iter);
 677}
 678#endif /* IPv6 */
 679
 680/**
 681 * netlbl_domhsh_walk - Iterate through the domain mapping hash table
 682 * @skip_bkt: the number of buckets to skip at the start
 683 * @skip_chain: the number of entries to skip in the first iterated bucket
 684 * @callback: callback for each entry
 685 * @cb_arg: argument for the callback function
 686 *
 687 * Description:
 688 * Interate over the domain mapping hash table, skipping the first @skip_bkt
 689 * buckets and @skip_chain entries.  For each entry in the table call
 690 * @callback, if @callback returns a negative value stop 'walking' through the
 691 * table and return.  Updates the values in @skip_bkt and @skip_chain on
 692 * return.  Returns zero on success, negative values on failure.
 693 *
 694 */
 695int netlbl_domhsh_walk(u32 *skip_bkt,
 696                     u32 *skip_chain,
 697                     int (*callback) (struct netlbl_dom_map *entry, void *arg),
 698                     void *cb_arg)
 699{
 700        int ret_val = -ENOENT;
 701        u32 iter_bkt;
 702        struct list_head *iter_list;
 703        struct netlbl_dom_map *iter_entry;
 704        u32 chain_cnt = 0;
 705
 706        rcu_read_lock();
 707        for (iter_bkt = *skip_bkt;
 708             iter_bkt < rcu_dereference(netlbl_domhsh)->size;
 709             iter_bkt++, chain_cnt = 0) {
 710                iter_list = &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt];
 711                list_for_each_entry_rcu(iter_entry, iter_list, list)
 712                        if (iter_entry->valid) {
 713                                if (chain_cnt++ < *skip_chain)
 714                                        continue;
 715                                ret_val = callback(iter_entry, cb_arg);
 716                                if (ret_val < 0) {
 717                                        chain_cnt--;
 718                                        goto walk_return;
 719                                }
 720                        }
 721        }
 722
 723walk_return:
 724        rcu_read_unlock();
 725        *skip_bkt = iter_bkt;
 726        *skip_chain = chain_cnt;
 727        return ret_val;
 728}
 729
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