/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include "os.h"#include <mp.h>#include <libsec.h> typedef struct State{	QLock		lock;	int		seeded;	uvlong		seed;	DES3state	des3;} State;static State x917state; static voidX917(uchar *rand, int nrand){	int i, m, n8;	uvlong I, x; 	/* 1. Compute intermediate value I = Ek(time). */	I = nsec();	triple_block_cipher(x917state.des3.expanded, (uchar*)&I, 0); /* two-key EDE */ 	/* 2. x[i] = Ek(I^seed);  seed = Ek(x[i]^I); */	m = (nrand+7)/8;	for(i=0; i<m; i++){		x = I ^ x917state.seed;		triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0);		n8 = (nrand>8) ? 8 : nrand;		memcpy(rand, (uchar*)&x, n8);		rand += 8;		nrand -= 8;		x ^= I;		triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0);		x917state.seed = x;	}} static voidX917init(void){	int n;	uchar mix[128];	uchar key3[3][8];	ulong *ulp; 	ulp = (ulong*)key3;	for(n = 0; n < sizeof(key3)/sizeof(ulong); n++)		ulp[n] = truerand();	setupDES3state(&x917state.des3, key3, nil);	X917(mix, sizeof mix);	x917state.seeded = 1;} voidgenrandom(uchar *p, int n){	qlock(&x917state.lock);	if(x917state.seeded == 0)		X917init();	X917(p, n);	qunlock(&x917state.lock);}