inet/ether_hton.c

   1 /* Copyright (C) 1996 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 <netinet/ether.h>
  21 #include <netinet/if_ether.h>
  22
  23 #include "../nss/nsswitch.h"
  24
  25 /* Because the `ethers' lookup does not fit so well in the scheme so
  26    we define a dummy struct here which helps us to use the available
  27    functions.  */
  28 struct etherent
  29 {
  30   const char *e_name;
  31   struct ether_addr e_addr;
  32 };
  33
  34
  35 /* Type of the lookup function we need here.  */
  36 typedef int (*lookup_function) (const char *, struct etherent *, char *, int);
  37
  38 /* The lookup function for the first entry of this service.  */
  39 extern int __nss_ethers_lookup (service_user **nip, const char *name,
  40                                 void **fctp);
  41
  42
  43 int
  44 ether_hostton (const char *hostname, struct ether_addr *addr)
  45 {
  46   static service_user *startp = NULL;
  47   static lookup_function start_fct;
  48   service_user *nip;
  49   lookup_function fct;
  50   int no_more;
  51   enum nss_status status = NSS_STATUS_UNAVAIL;
  52   struct etherent etherent;
  53
  54   if (startp == NULL)
  55     {
  56       no_more = __nss_ethers_lookup (&nip, "gethostton_r", (void **) &fct);
  57       if (no_more)
  58         startp = (service_user *) -1;
  59       else
  60         {
  61           startp = nip;
  62           start_fct = fct;
  63         }
  64     }
  65   else
  66     {
  67       fct = start_fct;
  68       no_more = (nip = startp) == (service_user *) -1;
  69     }
  70
  71   while (no_more == 0)
  72     {
  73       char buffer[1024];
  74
  75       status = (*fct) (hostname, &etherent, buffer, sizeof buffer);
  76
  77       no_more = __nss_next (&nip, "gethostton_r", (void **) &fct, status, 0);
  78     }
  79
  80   if (status == NSS_STATUS_SUCCESS)
  81     memcpy (addr, etherent.e_addr.ether_addr_octet,
  82             sizeof (struct ether_addr));
  83
  84   return status == NSS_STATUS_SUCCESS ? 0 : -1;
  85 }