cloudstack/vnet/src/vnet-module/random.c

88 lines
2.1 KiB
C

/*
* Copyright (C) 2004, 2005 Mike Wray <mike.wray@hp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program 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 General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free software Foundation, Inc.,
* 59 Temple Place, suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/random.h>
#include "hash_table.h"
#define MODULE_NAME "RANDOM"
#define DEBUG 1
#undef DEBUG
#include "debug.h"
/** @file
* Source of randomness.
* Current implementation is not enough.
* Needs to be cryptographically strong.
*/
static unsigned long seed = 0;
static unsigned long count = 0;
/** Contribute some random bytes.
*
* @param src bytes to contribute
* @param src_n number of bytes
*/
void add_random_bytes(const void *src, int src_n){
++count;
seed = hash_hvoid(seed, &count, sizeof(count));
seed = hash_hvoid(seed, src, src_n);
}
/** Get one random byte.
*
* @return random byte
*/
int get_random_byte(void){
int tmp = jiffies;
add_random_bytes(&tmp, sizeof(tmp));
return seed;
}
#ifndef __KERNEL__
/* Get some random bytes.
*
* @param dst destination for the bytes
* @param dst_n number of bytes to get
*/
void get_random_bytes(void *dst, int dst_n){
int i;
char *p = (char *)dst;
for(i = 0; i < dst_n; i++){
*p++ = get_random_byte();
}
}
#endif
int __init random_module_init(void){
int dummy;
int tmp = jiffies;
seed = (unsigned long)&dummy;
add_random_bytes(&tmp, sizeof(tmp));
return 0;
}
void __exit random_module_exit(void){
}