epan/iana-ip.c

   1 /* iana-ip.c
   2  *
   3  * Wireshark - Network traffic analyzer
   4  * By Gerald Combs <gerald@wireshark.org>
   5  * Copyright 1998 Gerald Combs
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-or-later
   8  */
   9
  10 #include "iana-ip.h"
  11
  12 #include "iana-ip-data.c"
  13
  14 static int
  15 compare_ipv4_block(const void *key, const void *element)
  16 {
  17     const uint32_t *ipnum = key;
  18     const struct ws_iana_ip_special_block *ptr = element;
  19
  20     uint32_t val = *ipnum & ptr->u_ip.ipv4.nmask;
  21
  22     if (val < ptr->u_ip.ipv4.addr)
  23         return -1;
  24     if (val > ptr->u_ip.ipv4.addr)
  25         return 1;
  26     return 0;
  27 }
  28
  29 const struct ws_iana_ip_special_block *
  30 ws_iana_ipv4_special_block_lookup(uint32_t ipnum)
  31 {
  32     return bsearch(&ipnum, __ipv4_special_block, G_N_ELEMENTS(__ipv4_special_block),
  33                     sizeof(struct ws_iana_ip_special_block), compare_ipv4_block);
  34 }
  35
  36 static const uint8_t bitmasks[9] =
  37     { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
  38
  39 static int
  40 compare_ipv6_block(const void *key, const void *element)
  41 {
  42     const ws_in6_addr *addr = key;
  43     const struct ws_iana_ip_special_block *ptr = element;
  44     uint32_t prefix;
  45     int pos = 0;
  46     int byte_a, byte_b;
  47
  48     prefix = ptr->u_ip.ipv6.prefix;
  49
  50     while (prefix >= 8) {
  51         byte_a = addr->bytes[pos];
  52         byte_b = ptr->u_ip.ipv6.addr.bytes[pos];
  53         if (byte_a != byte_b)
  54             return byte_a - byte_b;
  55
  56         prefix -= 8;
  57         pos++;
  58     }
  59
  60     if (prefix != 0) {
  61         byte_a = addr->bytes[pos] & bitmasks[prefix];
  62         byte_b = ptr->u_ip.ipv6.addr.bytes[pos];
  63         if (byte_a != byte_b)
  64             return byte_a - byte_b;
  65     }
  66
  67     return 0;
  68 }
  69
  70 const struct ws_iana_ip_special_block *
  71 ws_iana_ipv6_special_block_lookup(const ws_in6_addr *addr)
  72 {
  73     return bsearch(addr, __ipv6_special_block, G_N_ELEMENTS(__ipv6_special_block),
  74                     sizeof(struct ws_iana_ip_special_block), compare_ipv6_block);
  75 }