114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
/*
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* magic.c - PPP Magic Number routines.
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*
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* Copyright (c) 1989 Carnegie Mellon University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by Carnegie Mellon University. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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char magic_rcsid[] = "$Id$";
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include <sys/utsname.h>
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#include "fsm.h"
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#include "ipppd.h"
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#include "magic.h"
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#if 0
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static u_int32_t next; /* Next value to return */
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#endif
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extern long mrand48 __P((void));
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extern void srand48 __P((long));
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/*
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* magic_init - Initialize the magic number generator.
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*
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* Attempts to compute a random number seed which will not repeat.
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* The current method uses the current hostid, current process ID
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* and current time, currently.
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*/
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void
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magic_init()
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{
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long seed;
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struct timeval t;
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struct utsname uts;
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unsigned long val=0x12345678;
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int i;
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gettimeofday(&t, NULL);
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if(uname(&uts)==0) {
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unsigned char *p = (unsigned char *) &uts;
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int len = sizeof(struct utsname);
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int step=47;
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if(len % step == 0) /* unlikely, but ;) */
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step = 43;
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for(i=0;i<len;i++) {
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if(val & 0x80000000)
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val = ( (val<<1) + p[ (i*step)%len ]) + 1;
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else
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val = ( (val<<1) + p[ (i*step)%len ]);
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val &= 0xffffffff;
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}
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}
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else
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val = gethostid();
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seed = val ^ t.tv_sec ^ t.tv_usec ^ getpid();
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srand48(seed);
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}
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/*
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* magic - Returns the next magic number.
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*/
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u_int32_t
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magic(void)
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{
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return (u_int32_t) mrand48();
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}
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#ifdef NO_DRAND48
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/*
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* Substitute procedures for those systems which don't have
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* drand48 et al.
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*/
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double
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drand48()
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{
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return (double)random() / (double)0x7fffffffL; /* 2**31-1 */
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}
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long
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mrand48()
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{
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return random();
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}
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void
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srand48(seedval)
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long seedval;
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{
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srandom((int)seedval);
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}
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#endif
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