sysdeps/unix/sysv/linux/setsourcefilter.c

   1 /* Set source filter.  Linux version.
   2    Copyright (C) 2004-2024 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 <errno.h>
  20 #include <string.h>
  21 #include <netinet/in.h>
  22 #include <scratch_buffer.h>
  23 #include "getsourcefilter.h"
  24
  25
  26 int
  27 setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
  28                  socklen_t grouplen, uint32_t fmode, uint32_t numsrc,
  29                  const struct sockaddr_storage *slist)
  30 {
  31   /* We have to create an struct ip_msfilter object which we can pass
  32      to the kernel.  */
  33   size_t needed = GROUP_FILTER_SIZE (numsrc);
  34
  35   struct scratch_buffer buf;
  36   scratch_buffer_init (&buf);
  37   if (!scratch_buffer_set_array_size (&buf, 1, needed))
  38     return -1;
  39   struct group_filter *gf = buf.data;
  40
  41   gf->gf_interface = interface;
  42   memcpy (&gf->gf_group, group, grouplen);
  43   gf->gf_fmode = fmode;
  44   gf->gf_numsrc = numsrc;
  45   memcpy (gf->gf_slist, slist, numsrc * sizeof (struct sockaddr_storage));
  46
  47   /* We need to provide the appropriate socket level value.  */
  48   int result;
  49   int sol = __get_sol (group->sa_family, grouplen);
  50   if (sol == -1)
  51     {
  52       __set_errno (EINVAL);
  53       result = -1;
  54     }
  55   else
  56     result = __setsockopt (s, sol, MCAST_MSFILTER, gf, needed);
  57
  58   scratch_buffer_free (&buf);
  59
  60   return result;
  61 }