/* Return point to next ancillary data entry in message header.
   Copyright (C) 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <sys/socket.h>


struct cmsghdr *
__cmsg_nxthdr (struct msghdr *mhdr, struct cmsghdr *cmsg)
{
  unsigned char *p;

  if ((size_t) cmsg->cmsg_len < sizeof (struct cmsghdr))
    /* The kernel header does this so there may be a reason.  */
    return NULL;

  p = (((unsigned char *) cmsg)
       + ((cmsg->cmsg_len + sizeof (long int) - 1) & ~sizeof (long int)));
  if (p >= (unsigned char *) mhdr->msg_control + mhdr->msg_controllen)
    /* No more entries.  */
    return NULL;
  return (struct cmsghdr *) p;
}