sysdeps/unix/sysv/linux/setsourcefilter.c

   1 /* Set source filter.  Linux version.
   2    Copyright (C) 2004, 2006 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <alloca.h>
  21 #include <errno.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <netinet/in.h>
  25 #include <sys/socket.h>
  26
  27
  28 /* Defined in getsourcefilter.c.  */
  29 extern int __get_sol (int af, socklen_t len);
  30
  31
  32 int
  33 setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
  34                  socklen_t grouplen, uint32_t fmode, uint32_t numsrc,
  35                  const struct sockaddr_storage *slist)
  36 {
  37   /* We have to create an struct ip_msfilter object which we can pass
  38      to the kernel.  */
  39   size_t needed = GROUP_FILTER_SIZE (numsrc);
  40   int use_alloca = __libc_use_alloca (needed);
  41
  42   struct group_filter *gf;
  43   if (use_alloca)
  44     gf = (struct group_filter *) alloca (needed);
  45   else
  46     {
  47       gf = (struct group_filter *) malloc (needed);
  48       if (gf == NULL)
  49         return -1;
  50     }
  51
  52   gf->gf_interface = interface;
  53   memcpy (&gf->gf_group, group, grouplen);
  54   gf->gf_fmode = fmode;
  55   gf->gf_numsrc = numsrc;
  56   memcpy (gf->gf_slist, slist, numsrc * sizeof (struct sockaddr_storage));
  57
  58   /* We need to provide the appropriate socket level value.  */
  59   int result;
  60   int sol = __get_sol (group->sa_family, grouplen);
  61   if (sol == -1)
  62     {
  63       __set_errno (EINVAL);
  64       result = -1;
  65     }
  66   else
  67     result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
  68
  69   if (! use_alloca)
  70     {
  71       int save_errno = errno;
  72       free (gf);
  73       __set_errno (save_errno);
  74     }
  75
  76   return result;
  77 }