inet/ether_hton.c

   1 /* Copyright (C) 1996, 1999 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <netinet/ether.h>
  22 #include <netinet/if_ether.h>
  23 #include <string.h>
  24
  25 #include "../nss/nsswitch.h"
  26
  27 /* Type of the lookup function we need here.  */
  28 typedef int (*lookup_function) (const char *, struct etherent *, char *, int,
  29                                 int *);
  30
  31 /* The lookup function for the first entry of this service.  */
  32 extern int __nss_ethers_lookup (service_user **nip, const char *name,
  33                                 void **fctp);
  34
  35
  36 int
  37 ether_hostton (const char *hostname, struct ether_addr *addr)
  38 {
  39   static service_user *startp;
  40   static lookup_function start_fct;
  41   service_user *nip;
  42   lookup_function fct;
  43   int no_more;
  44   enum nss_status status = NSS_STATUS_UNAVAIL;
  45   struct etherent etherent;
  46
  47   if (startp == NULL)
  48     {
  49       no_more = __nss_ethers_lookup (&nip, "gethostton_r", (void **) &fct);
  50       if (no_more)
  51         startp = (service_user *) -1;
  52       else
  53         {
  54           startp = nip;
  55           start_fct = fct;
  56         }
  57     }
  58   else
  59     {
  60       fct = start_fct;
  61       no_more = (nip = startp) == (service_user *) -1;
  62     }
  63
  64   while (no_more == 0)
  65     {
  66       char buffer[1024];
  67
  68       status = (*fct) (hostname, &etherent, buffer, sizeof buffer, &errno);
  69
  70       no_more = __nss_next (&nip, "gethostton_r", (void **) &fct, status, 0);
  71     }
  72
  73   if (status == NSS_STATUS_SUCCESS)
  74     memcpy (addr, etherent.e_addr.ether_addr_octet,
  75             sizeof (struct ether_addr));
  76
  77   return status == NSS_STATUS_SUCCESS ? 0 : -1;
  78 }