src/core/or/address_set.c

   1 /* Copyright (c) 2018-2021, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * \file address_set.c
   6  * \brief Implementation for a set of addresses.
   7  *
   8  * This module was first written on a semi-emergency basis to improve the
   9  * robustness of the anti-DoS module.  As such, it's written in a pretty
  10  * conservative way, and should be susceptible to improvement later on.
  11  **/
  12
  13 #include "orconfig.h"
  14 #include "core/or/address_set.h"
  15 #include "lib/net/address.h"
  16 #include "lib/container/bloomfilt.h"
  17 #include "lib/crypt_ops/crypto_rand.h"
  18
  19 /** Wrap our hash function to have the signature that the bloom filter
  20  * needs. */
  21 static uint64_t
  22 bloomfilt_addr_hash(const struct sipkey *key,
  23                     const void *item)
  24 {
  25   return tor_addr_keyed_hash(key, item);
  26 }
  27
  28 /**
  29  * Allocate and return an address_set, suitable for holding up to
  30  * <b>max_address_guess</b> distinct values.
  31  */
  32 address_set_t *
  33 address_set_new(int max_addresses_guess)
  34 {
  35   uint8_t k[BLOOMFILT_KEY_LEN];
  36   crypto_rand((void*)k, sizeof(k));
  37   return bloomfilt_new(max_addresses_guess, bloomfilt_addr_hash, k);
  38 }
  39
  40 /**
  41  * Add <b>addr</b> to <b>set</b>.
  42  *
  43  * All future queries for <b>addr</b> in set will return true. Removing
  44  * items is not possible.
  45  */
  46 void
  47 address_set_add(address_set_t *set, const struct tor_addr_t *addr)
  48 {
  49   bloomfilt_add(set, addr);
  50 }
  51
  52 /** As address_set_add(), but take an ipv4 address in host order. */
  53 void
  54 address_set_add_ipv4h(address_set_t *set, uint32_t addr)
  55 {
  56   tor_addr_t a;
  57   tor_addr_from_ipv4h(&a, addr);
  58   address_set_add(set, &a);
  59 }
  60
  61 /**
  62  * Return true if <b>addr</b> is a member of <b>set</b>.  (And probably,
  63  * return false if <b>addr</b> is not a member of set.)
  64  */
  65 int
  66 address_set_probably_contains(const address_set_t *set,
  67                               const struct tor_addr_t *addr)
  68 {
  69   return bloomfilt_probably_contains(set, addr);
  70 }