sysdeps/unix/sysv/linux/setsourcefilter.c

   1 /* Set source filter.  Linux version.
   2    Copyright (C) 2004 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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <alloca.h>
  22 #include <errno.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <netinet/in.h>
  26 #include <sys/socket.h>
  27
  28
  29 /* Defined in getsourcefilter.c.  */
  30 extern int __get_sol (int af, socklen_t len);
  31
  32
  33 int
  34 setsourcefilter (int s, uint32_t interface, const struct sockaddr *group,
  35                  socklen_t grouplen, uint32_t fmode, uint32_t numsrc,
  36                  const struct sockaddr_storage *slist)
  37 {
  38   /* We have to create an struct ip_msfilter object which we can pass
  39      to the kernel.  */
  40   size_t needed = GROUP_FILTER_SIZE (numsrc);
  41   int use_alloca = __libc_use_alloca (needed);
  42
  43   struct group_filter *gf;
  44   if (use_alloca)
  45     gf = (struct group_filter *) alloca (needed);
  46   else
  47     {
  48       gf = (struct group_filter *) malloc (needed);
  49       if (gf == NULL)
  50         return -1;
  51     }
  52
  53   gf->gf_interface = interface;
  54   memcpy (&gf->gf_group, group, grouplen);
  55   gf->gf_fmode = fmode;
  56   gf->gf_numsrc = numsrc;
  57   memcpy (gf->gf_slist, slist, numsrc * sizeof (struct sockaddr_storage));
  58
  59   /* We need to provide the appropriate socket level value.  */
  60   int sol = __get_sol (group->sa_family, grouplen);
  61   if (sol == -1)
  62     {
  63       __set_errno (EINVAL);
  64       return -1;
  65     }
  66
  67   int 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 }