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/* *	Generic address resultion entity * *	Authors: *	net_random Alan Cox *	net_ratelimit Andy Kleen * *	Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> * *	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. */ #include <linux/module.h>#include <linux/jiffies.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/string.h>#include <linux/types.h>#include <linux/random.h>#include <linux/percpu.h>#include <linux/init.h> #include <asm/byteorder.h>#include <asm/system.h>#include <asm/uaccess.h> /*  This is a maximally equidistributed combined Tausworthe generator  based on code from GNU Scientific Library 1.5 (30 Jun 2004)    x_n = (s1_n ^ s2_n ^ s3_n)     s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))   s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))   s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))    The period of this generator is about 2^88.    From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe   Generators", Mathematics of Computation, 65, 213 (1996), 203--213.    This is available on the net from L'Ecuyer's home page,    http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps   ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps     There is an erratum in the paper "Tables of Maximally   Equidistributed Combined LFSR Generators", Mathematics of   Computation, 68, 225 (1999), 261--269:   http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps         ... the k_j most significant bits of z_j must be non-        zero, for each j. (Note: this restriction also applies to the         computer code given in [4], but was mistakenly not mentioned in        that paper.)      This affects the seeding procedure by imposing the requirement   s1 > 1, s2 > 7, s3 > 15. */struct nrnd_state {	u32 s1, s2, s3;}; static DEFINE_PER_CPU(struct nrnd_state, net_rand_state); static u32 __net_random(struct nrnd_state *state){#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b) 	state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);	state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);	state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17); 	return (state->s1 ^ state->s2 ^ state->s3);} static void __net_srandom(struct nrnd_state *state, unsigned long s){	if (s == 0)		s = 1;      /* default seed is 1 */ #define LCG(n) (69069 * n)	state->s1 = LCG(s);	state->s2 = LCG(state->s1);	state->s3 = LCG(state->s2); 	/* "warm it up" */	__net_random(state);	__net_random(state);	__net_random(state);	__net_random(state);	__net_random(state);	__net_random(state);}  unsigned long net_random(void){	unsigned long r;	struct nrnd_state *state = &get_cpu_var(net_rand_state);	r = __net_random(state);	put_cpu_var(state);	return r;}  void net_srandom(unsigned long entropy){	struct nrnd_state *state = &get_cpu_var(net_rand_state);	__net_srandom(state, state->s1^entropy);	put_cpu_var(state);} void __init net_random_init(void){	int i; 	for (i = 0; i < NR_CPUS; i++) {		struct nrnd_state *state = &per_cpu(net_rand_state,i);		__net_srandom(state, i+jiffies);	}} static int net_random_reseed(void){	int i;	unsigned long seed[NR_CPUS]; 	get_random_bytes(seed, sizeof(seed));	for (i = 0; i < NR_CPUS; i++) {		struct nrnd_state *state = &per_cpu(net_rand_state,i);		__net_srandom(state, seed[i]);	}	return 0;}late_initcall(net_random_reseed); int net_msg_cost = 5*HZ;int net_msg_burst = 10; /*  * All net warning printk()s should be guarded by this function. */ int net_ratelimit(void){	return __printk_ratelimit(net_msg_cost, net_msg_burst);} EXPORT_SYMBOL(net_random);EXPORT_SYMBOL(net_ratelimit);EXPORT_SYMBOL(net_srandom); /* * Convert an ASCII string to binary IP. * This is outside of net/ipv4/ because various code that uses IP addresses * is otherwise not dependent on the TCP/IP stack. */ __u32 in_aton(const char *str){	unsigned long l;	unsigned int val;	int i; 	l = 0;	for (i = 0; i < 4; i++)	{		l <<= 8;		if (*str != '\0')		{			val = 0;			while (*str != '\0' && *str != '.')			{				val *= 10;				val += *str - '0';				str++;			}			l |= val;			if (*str != '\0')				str++;		}	}	return(htonl(l));} EXPORT_SYMBOL(in_aton);