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 #include <string.h>
  23
  24 #include "../nss/nsswitch.h"
  25
  26 /* Because the `ethers' lookup does not fit so well in the scheme so
  27    we define a dummy struct here which helps us to use the available
  28    functions.  */
  29 struct etherent
  30 {
  31   const char *e_name;
  32   struct ether_addr e_addr;
  33 };
  34
  35
  36 /* Type of the lookup function we need here.  */
  37 typedef int (*lookup_function) (const char *, struct etherent *, char *, int);
  38
  39 /* The lookup function for the first entry of this service.  */
  40 extern int __nss_ethers_lookup (service_user **nip, const char *name,
  41                                 void **fctp);
  42
  43
  44 int
  45 ether_hostton (const char *hostname, struct ether_addr *addr)
  46 {
  47   static service_user *startp = NULL;
  48   static lookup_function start_fct;
  49   service_user *nip;
  50   lookup_function fct;
  51   int no_more;
  52   enum nss_status status = NSS_STATUS_UNAVAIL;
  53   struct etherent etherent;
  54
  55   if (startp == NULL)
  56     {
  57       no_more = __nss_ethers_lookup (&nip, "gethostton_r", (void **) &fct);
  58       if (no_more)
  59         startp = (service_user *) -1;
  60       else
  61         {
  62           startp = nip;
  63           start_fct = fct;
  64         }
  65     }
  66   else
  67     {
  68       fct = start_fct;
  69       no_more = (nip = startp) == (service_user *) -1;
  70     }
  71
  72   while (no_more == 0)
  73     {
  74       char buffer[1024];
  75
  76       status = (*fct) (hostname, &etherent, buffer, sizeof buffer);
  77
  78       no_more = __nss_next (&nip, "gethostton_r", (void **) &fct, status, 0);
  79     }
  80
  81   if (status == NSS_STATUS_SUCCESS)
  82     memcpy (addr, etherent.e_addr.ether_addr_octet,
  83             sizeof (struct ether_addr));
  84
  85   return status == NSS_STATUS_SUCCESS ? 0 : -1;
  86 }