/* 

 * netof - return the net address part of an ip address in a sockaddr_u structure

 *         (zero out host part)

 */

#include <config.h>

#include <stdio.h>

#include <syslog.h>

#include "ntp_fp.h"

#include "ntp_net.h"

#include "ntp_stdlib.h"

#include "ntp.h"

/* 

 * Return the network portion of a host address.  Used by ntp_io.c

 * findbcastinter() to find a multicast/broadcast interface for

 * a given remote address.  Note static storage is used, with room

 * for only two addresses, which is all that is needed at present.

 * 

 */

sockaddr_u *

netof(

  sockaddr_u *hostaddr

  )

{

  static sockaddr_u netofbuf[2];

  static int    next_netofbuf;

  u_int32     netnum;

  sockaddr_u *    netaddr;

  netaddr = &netofbuf[next_netofbuf];

  next_netofbuf = (next_netofbuf + 1) % COUNTOF(netofbuf);

  memcpy(netaddr, hostaddr, sizeof(*netaddr));

  if (IS_IPV4(netaddr)) {

    /*

     * We live in a modern classless IPv4 world.  Assume /24.

     */

    netnum = SRCADR(netaddr) & IN_CLASSC_NET;

    SET_ADDR4(netaddr, netnum);

  } else if (IS_IPV6(netaddr))

    /* assume the typical /64 subnet size */

    zero_mem(&NSRCADR6(netaddr)[8], 8);

#ifdef DEBUG

  else {

    msyslog(LOG_ERR, "netof unknown AF %d", AF(netaddr));

    exit(1);

  }

#endif

  return netaddr;

}