inet/ether_aton_r.c

   1 /* Copyright (C) 1996-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <ctype.h>
  20 #include <stdlib.h>
  21 #include <netinet/ether.h>
  22 #include <netinet/if_ether.h>
  23
  24
  25 struct ether_addr *
  26 ether_aton_r (const char *asc, struct ether_addr *addr)
  27 {
  28   size_t cnt;
  29
  30   for (cnt = 0; cnt < 6; ++cnt)
  31     {
  32       unsigned int number;
  33       char ch;
  34
  35       ch = _tolower (*asc++);
  36       if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
  37         return NULL;
  38       number = isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
  39
  40       ch = _tolower (*asc);
  41       if ((cnt < 5 && ch != ':') || (cnt == 5 && ch != '\0' && !isspace (ch)))
  42         {
  43           ++asc;
  44           if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
  45             return NULL;
  46           number <<= 4;
  47           number += isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
  48
  49           ch = *asc;
  50           if (cnt < 5 && ch != ':')
  51             return NULL;
  52         }
  53
  54       /* Store result.  */
  55       addr->ether_addr_octet[cnt] = (unsigned char) number;
  56
  57       /* Skip ':'.  */
  58       ++asc;
  59     }
  60
  61   return addr;
  62 }
  63 libc_hidden_def (ether_aton_r)