sysdeps/unix/sysv/linux/setipv4sourcefilter.c

   1 /* Set IPv4 source filter.  Linux version.
   2    Copyright (C) 2004-2013 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 int
  29 setipv4sourcefilter (int s, struct in_addr interface, struct in_addr group,
  30                      uint32_t fmode, uint32_t numsrc,
  31                      const struct in_addr *slist)
  32 {
  33   /* We have to create an struct ip_msfilter object which we can pass
  34      to the kernel.  */
  35   size_t needed = IP_MSFILTER_SIZE (numsrc);
  36   int use_alloca = __libc_use_alloca (needed);
  37
  38   struct ip_msfilter *imsf;
  39   if (use_alloca)
  40     imsf = (struct ip_msfilter *) alloca (needed);
  41   else
  42     {
  43       imsf = (struct ip_msfilter *) malloc (needed);
  44       if (imsf == NULL)
  45         return -1;
  46     }
  47
  48   imsf->imsf_multiaddr = group;
  49   imsf->imsf_interface = interface;
  50   imsf->imsf_fmode = fmode;
  51   imsf->imsf_numsrc = numsrc;
  52   memcpy (imsf->imsf_slist, slist, numsrc * sizeof (struct in_addr));
  53
  54   int result = __setsockopt (s, SOL_IP, IP_MSFILTER, imsf, needed);
  55
  56   if (! use_alloca)
  57     {
  58       int save_errno = errno;
  59       free (imsf);
  60       __set_errno (save_errno);
  61     }
  62
  63   return result;
  64 }