resolv/res_get_nsaddr.c

   1 /* Name server address at specified index in res_state.
   2    Copyright (C) 2015-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <resolv.h>
  21 #include <resolv-internal.h>
  22
  23 struct sockaddr *
  24 __res_get_nsaddr (res_state statp, unsigned int n)
  25 {
  26   assert (n < statp->nscount);
  27
  28   if (statp->nsaddr_list[n].sin_family == 0
  29       && statp->_u._ext.nsaddrs[n] != NULL)
  30     /* statp->_u._ext.nsaddrs[n] holds an address that is larger than
  31        struct sockaddr, and user code did not update
  32        statp->nsaddr_list[n].  */
  33     return (struct sockaddr *) statp->_u._ext.nsaddrs[n];
  34   else
  35     /* User code updated statp->nsaddr_list[n], or statp->nsaddr_list[n]
  36        has the same content as statp->_u._ext.nsaddrs[n].  */
  37     return (struct sockaddr *) (void *) &statp->nsaddr_list[n];
  38 }
  39 libc_hidden_def (__res_get_nsaddr)