inet/ether_aton_r.c

   1 /* Copyright (C) 1996-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <ctype.h>
  19 #include <stdlib.h>
  20 #include <netinet/ether.h>
  21 #include <netinet/if_ether.h>
  22
  23
  24 struct ether_addr *
  25 ether_aton_r (const char *asc, struct ether_addr *addr)
  26 {
  27   size_t cnt;
  28
  29   for (cnt = 0; cnt < 6; ++cnt)
  30     {
  31       unsigned int number;
  32       char ch;
  33
  34       ch = _tolower (*asc++);
  35       if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
  36         return NULL;
  37       number = isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
  38
  39       ch = _tolower (*asc);
  40       if ((cnt < 5 && ch != ':') || (cnt == 5 && ch != '\0' && !isspace (ch)))
  41         {
  42           ++asc;
  43           if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
  44             return NULL;
  45           number <<= 4;
  46           number += isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
  47
  48           ch = *asc;
  49           if (cnt < 5 && ch != ':')
  50             return NULL;
  51         }
  52
  53       /* Store result.  */
  54       addr->ether_addr_octet[cnt] = (unsigned char) number;
  55
  56       /* Skip ':'.  */
  57       ++asc;
  58     }
  59
  60   return addr;
  61 }
  62 libc_hidden_def (ether_aton_r)