sysdeps/unix/sysv/linux/setsourcefilter.c

   1 /* Set source filter.  Linux version.
   2    Copyright (C) 2004-2017 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 <stdint.h>
  25 #include <netinet/in.h>
  26 #include <sys/socket.h>
  27 #include "getsourcefilter.h"
  28
  29
  30 int
  31 setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
  32                  socklen_t grouplen, uint32_t fmode, uint32_t numsrc,
  33                  const struct sockaddr_storage *slist)
  34 {
  35   /* We have to create an struct ip_msfilter object which we can pass
  36      to the kernel.  */
  37   size_t needed = GROUP_FILTER_SIZE (numsrc);
  38   int use_alloca = __libc_use_alloca (needed);
  39
  40   struct group_filter *gf;
  41   if (use_alloca)
  42     gf = (struct group_filter *) alloca (needed);
  43   else
  44     {
  45       gf = (struct group_filter *) malloc (needed);
  46       if (gf == NULL)
  47         return -1;
  48     }
  49
  50   gf->gf_interface = interface;
  51   memcpy (&gf->gf_group, group, grouplen);
  52   gf->gf_fmode = fmode;
  53   gf->gf_numsrc = numsrc;
  54   memcpy (gf->gf_slist, slist, numsrc * sizeof (struct sockaddr_storage));
  55
  56   /* We need to provide the appropriate socket level value.  */
  57   int result;
  58   int sol = __get_sol (group->sa_family, grouplen);
  59   if (sol == -1)
  60     {
  61       __set_errno (EINVAL);
  62       result = -1;
  63     }
  64   else
  65     result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
  66
  67   if (! use_alloca)
  68     {
  69       int save_errno = errno;
  70       free (gf);
  71       __set_errno (save_errno);
  72     }
  73
  74   return result;
  75 }