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 /* Because the `ethers' lookup does not fit so well in the scheme so
  28    we define a dummy struct here which helps us to use the available
  29    functions.  */
  30 struct etherent
  31 {
  32   const char *e_name;
  33   struct ether_addr e_addr;
  34 };
  35
  36
  37 /* Type of the lookup function we need here.  */
  38 typedef int (*lookup_function) (const char *, struct etherent *, char *, int,
  39                                 int *);
  40
  41 /* The lookup function for the first entry of this service.  */
  42 extern int __nss_ethers_lookup (service_user **nip, const char *name,
  43                                 void **fctp);
  44
  45
  46 int
  47 ether_hostton (const char *hostname, struct ether_addr *addr)
  48 {
  49   static service_user *startp;
  50   static lookup_function start_fct;
  51   service_user *nip;
  52   lookup_function fct;
  53   int no_more;
  54   enum nss_status status = NSS_STATUS_UNAVAIL;
  55   struct etherent etherent;
  56
  57   if (startp == NULL)
  58     {
  59       no_more = __nss_ethers_lookup (&nip, "gethostton_r", (void **) &fct);
  60       if (no_more)
  61         startp = (service_user *) -1;
  62       else
  63         {
  64           startp = nip;
  65           start_fct = fct;
  66         }
  67     }
  68   else
  69     {
  70       fct = start_fct;
  71       no_more = (nip = startp) == (service_user *) -1;
  72     }
  73
  74   while (no_more == 0)
  75     {
  76       char buffer[1024];
  77
  78       status = (*fct) (hostname, &etherent, buffer, sizeof buffer, &errno);
  79
  80       no_more = __nss_next (&nip, "gethostton_r", (void **) &fct, status, 0);
  81     }
  82
  83   if (status == NSS_STATUS_SUCCESS)
  84     memcpy (addr, etherent.e_addr.ether_addr_octet,
  85             sizeof (struct ether_addr));
  86
  87   return status == NSS_STATUS_SUCCESS ? 0 : -1;
  88 }