inet/ether_hton.c

   1 /* Copyright (C) 1996-2022 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <netinet/ether.h>
  20 #include <netinet/if_ether.h>
  21 #include <string.h>
  22
  23 #include "../nss/nsswitch.h"
  24
  25 /* Type of the lookup function we need here.  */
  26 typedef int (*lookup_function) (const char *, struct etherent *, char *, int,
  27                                 int *);
  28
  29 int
  30 ether_hostton (const char *hostname, struct ether_addr *addr)
  31 {
  32   nss_action_list nip;
  33   union
  34   {
  35     lookup_function f;
  36     void *ptr;
  37   } fct;
  38   int no_more;
  39   enum nss_status status = NSS_STATUS_UNAVAIL;
  40   struct etherent etherent;
  41
  42   no_more = __nss_ethers_lookup2 (&nip, "gethostton_r", NULL, &fct.ptr);
  43
  44   while (no_more == 0)
  45     {
  46       char buffer[1024];
  47
  48       status = (*fct.f) (hostname, &etherent, buffer, sizeof buffer, &errno);
  49
  50       no_more = __nss_next2 (&nip, "gethostton_r", NULL, &fct.ptr, status, 0);
  51     }
  52
  53   if (status == NSS_STATUS_SUCCESS)
  54     memcpy (addr, etherent.e_addr.ether_addr_octet,
  55             sizeof (struct ether_addr));
  56
  57   return status == NSS_STATUS_SUCCESS ? 0 : -1;
  58 }