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
  17 not, 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
  39 int
  40 ether_hostton (const char *hostname, struct ether_addr *addr)
  41 {
  42   static service_user *startp = NULL;
  43   static lookup_function start_fct;
  44   service_user *nip;
  45   lookup_function fct;
  46   int no_more;
  47   int result;
  48   enum nss_status status = NSS_STATUS_UNAVAIL;
  49   struct etherent etherent;
  50
  51   if (startp == NULL)
  52     {
  53       no_more = __nss_ethers_lookup (&nip, "gethostton_r", (void **) &fct);
  54       if (no_more)
  55         startp = (service_user *) -1;
  56       else
  57         {
  58           startp = nip;
  59           start_fct = fct;
  60         }
  61     }
  62   else
  63     {
  64       fct = start_fct;
  65       no_more = (nip = startp) == (service_user *) -1;
  66     }
  67
  68   while (no_more == 0)
  69     {
  70       char buffer[1024];
  71
  72       status = (*fct) (hostname, &etherent, buffer, sizeof buffer);
  73
  74       no_more = __nss_next (&nip, "gethostton_r", (void **) &fct, status, 0);
  75     }
  76
  77   if (status == NSS_STATUS_SUCCESS)
  78     memcpy (addr, etherent.e_addr.ether_addr_octet,
  79             sizeof (struct ether_addr));
  80
  81   return status == NSS_STATUS_SUCCESS ? 0 : -1;
  82 }