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net: use common rand()/srand() functions

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Replace rand() with the functions from lib/. The link-local network code
stores its own seed, derived from the MAC address. Thus making it
independent from calls to srand() in other modules.

Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
This commit is contained in:
Michael Walle 2012-06-05 11:33:15 +00:00 committed by Albert ARIBAUD
parent 9acf1ca50d
commit 99e139d590
6 changed files with 34 additions and 82 deletions
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4
include/common.h
View file

@ -761,7 +761,9 @@ char * strmhz(char *buf, unsigned long hz);
#include <u-boot/crc.h>
/* lib/rand.c */
#ifdef CONFIG_RANDOM_MACADDR
#if defined(CONFIG_RANDOM_MACADDR) || \
defined(CONFIG_BOOTP_RANDOM_DELAY) || \
defined(CONFIG_CMD_LINK_LOCAL)
#define RAND_MAX -1U
void srand(unsigned int seed);
unsigned int rand(void);

4
lib/Makefile
View file

@ -67,8 +67,10 @@ COBJS-y += time.o
COBJS-$(CONFIG_BOOTP_PXE) += uuid.o
COBJS-y += vsprintf.o
COBJS-$(CONFIG_RANDOM_MACADDR) += rand.o
COBJS-$(CONFIG_BOOTP_RANDOM_DELAY) += rand.o
COBJS-$(CONFIG_CMD_LINK_LOCAL) += rand.o
COBJS := $(COBJS-y)
COBJS := $(sort $(COBJS-y))
SRCS := $(COBJS:.o=.c)
OBJS := $(addprefix $(obj),$(COBJS))

2
net/Makefile
View file

@ -34,8 +34,6 @@ COBJS-$(CONFIG_CMD_DNS) += dns.o
COBJS-$(CONFIG_CMD_NET) += eth.o
COBJS-$(CONFIG_CMD_LINK_LOCAL) += link_local.o
COBJS-$(CONFIG_CMD_NET) += net.o
COBJS-$(CONFIG_BOOTP_RANDOM_DELAY) += net_rand.o
COBJS-$(CONFIG_CMD_LINK_LOCAL) += net_rand.o
COBJS-$(CONFIG_CMD_NFS) += nfs.o
COBJS-$(CONFIG_CMD_PING) += ping.o
COBJS-$(CONFIG_CMD_RARP) += rarp.o

7
net/link_local.c
View file

@ -56,6 +56,7 @@ static unsigned conflicts;
static unsigned nprobes;
static unsigned nclaims;
static int ready;
static unsigned int seed;
static void link_local_timeout(void);
@ -68,7 +69,7 @@ static IPaddr_t pick(void)
unsigned tmp;
do {
tmp = rand() & IN_CLASSB_HOST;
tmp = rand_r(&seed) & IN_CLASSB_HOST;
} while (tmp > (IN_CLASSB_HOST - 0x0200));
return (IPaddr_t) htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
}
@ -78,7 +79,7 @@ static IPaddr_t pick(void)
*/
static inline unsigned random_delay_ms(unsigned secs)
{
return rand() % (secs * 1000);
return rand_r(&seed) % (secs * 1000);
}
static void configure_wait(void)
@ -109,7 +110,7 @@ void link_local_start(void)
}
NetOurSubnetMask = IN_CLASSB_NET;
srand_mac();
seed = seed_mac();
if (ip == 0)
ip = pick();

68
net/net_rand.c
View file

@ -1,68 +0,0 @@
/*
* Based on LiMon - BOOTP.
*
* Copyright 1994, 1995, 2000 Neil Russell.
* (See License)
* Copyright 2000 Roland Borde
* Copyright 2000 Paolo Scaffardi
* Copyright 2000-2004 Wolfgang Denk, wd@denx.de
*/
#include <common.h>
#include <net.h>
#include "net_rand.h"
static ulong seed1, seed2;
void srand_mac(void)
{
ulong tst1, tst2, m_mask;
ulong m_value = 0;
int reg;
unsigned char bi_enetaddr[6];
/* get our mac */
eth_getenv_enetaddr("ethaddr", bi_enetaddr);
debug("BootpRequest => Our Mac: ");
for (reg = 0; reg < 6; reg++)
debug("%x%c", bi_enetaddr[reg], reg == 5 ? '\n' : ':');
/* Mac-Manipulation 2 get seed1 */
tst1 = 0;
tst2 = 0;
for (reg = 2; reg < 6; reg++) {
tst1 = tst1 << 8;
tst1 = tst1 | bi_enetaddr[reg];
}
for (reg = 0; reg < 2; reg++) {
tst2 = tst2 | bi_enetaddr[reg];
tst2 = tst2 << 8;
}
seed1 = tst1^tst2;
/* Mirror seed1*/
m_mask = 0x1;
for (reg = 1; reg <= 32; reg++) {
m_value |= (m_mask & seed1);
seed1 = seed1 >> 1;
m_value = m_value << 1;
}
seed1 = m_value;
seed2 = 0xb78d0945;
}
unsigned long rand(void)
{
ulong sum;
/* Random Number Generator */
sum = seed1 + seed2;
if (sum < seed1 || sum < seed2)
sum++;
seed2 = seed1;
seed1 = sum;
return sum;
}

31
net/net_rand.h
View file

@ -9,18 +9,35 @@
#ifndef __NET_RAND_H__
#define __NET_RAND_H__
#define RAND_MAX 0xffffffff
#include <common.h>
/*
* Seed the random number generator using the eth0 MAC address
* Return a seed for the PRNG derived from the eth0 MAC address.
*/
void srand_mac(void);
static inline unsigned int seed_mac(void)
{
unsigned char enetaddr[6];
unsigned int seed;
/* get our mac */
eth_getenv_enetaddr("ethaddr", enetaddr);
seed = enetaddr[5];
seed ^= enetaddr[4] << 8;
seed ^= enetaddr[3] << 16;
seed ^= enetaddr[2] << 24;
seed ^= enetaddr[1];
seed ^= enetaddr[0] << 8;
return seed;
}
/*
* Get a random number (after seeding with MAC address)
*
* @return random number
* Seed the random number generator using the eth0 MAC address.
*/
unsigned long rand(void);
static inline void srand_mac(void)
{
srand(seed_mac());
}
#endif /* __NET_RAND_H__ */