freebsd-dev/usr.sbin/pppd/magic.c
1997-02-22 16:15:28 +00:00

91 lines
1.9 KiB
C

/*
* magic.c - PPP Magic Number routines.
*
* Copyright (c) 1989 Carnegie Mellon University.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by Carnegie Mellon University. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
static char rcsid[] = "$Id$";
#endif
#include <stdio.h>
#include <sys/types.h>
#include <sys/time.h>
#include "pppd.h"
#include "magic.h"
static u_int32_t next; /* Next value to return */
extern int gethostid __P((void));
extern long mrand48 __P((void));
extern void srand48 __P((long));
/*
* magic_init - Initialize the magic number generator.
*
* Attempts to compute a random number seed which will not repeat.
* The current method uses the current hostid, current process ID
* and current time, currently.
*/
void
magic_init()
{
long seed;
struct timeval t;
gettimeofday(&t, NULL);
seed = gethostid() ^ t.tv_sec ^ t.tv_usec ^ getpid();
srand48(seed);
}
/*
* magic - Returns the next magic number.
*/
u_int32_t
magic()
{
return (u_int32_t) mrand48();
}
#ifdef NO_DRAND48
/*
* Substitute procedures for those systems which don't have
* drand48 et al.
*/
double
drand48()
{
return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
}
long
mrand48()
{
return random();
}
void
srand48(seedval)
long seedval;
{
srandom((int)seedval);
}
#endif