[sorry for my first mail.. wasn't intented to be send]
Sorry for being too late on this.
Am Mittwoch 23 Mai 2012, 19:57:58 schrieb Joe Hershberger:
Make the MAC-seeded random number generator available to /net in general. MAC-seeded rand will be needed by link-local as well, so give it an interface.
Signed-off-by: Joe Hershberger joe.hershberger@ni.com Cc: Joe Hershberger joe.hershberger@gmail.com
Changes for v3:
- Lowercase hex
- Add blank line
- Always include header, even when it isn't needed
- Add function comments
net/Makefile | 1 + net/bootp.c | 67 ++++++++++--------------------------------------------- net/bootp.h | 3 -- net/net_rand.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ net/net_rand.h | 26 +++++++++++++++++++++ 5 files changed, 107 insertions(+), 58 deletions(-) create mode 100644 net/net_rand.c create mode 100644 net/net_rand.h
[..]
diff --git a/net/bootp.h b/net/bootp.h index ce73734..bf4e875 100644 --- a/net/bootp.h +++ b/net/bootp.h @@ -63,9 +63,6 @@ struct Bootp_t { extern ulong BootpID; /* ID of cur BOOTP request */ extern char BootFile[128]; /* Boot file name */ extern int BootpTry; -#ifdef CONFIG_BOOTP_RANDOM_DELAY -extern ulong seed1, seed2; /* seed for random BOOTP delay */ -#endif
/* Send a BOOTP request */ diff --git a/net/net_rand.c b/net/net_rand.c new file mode 100644 index 0000000..5387aba --- /dev/null +++ b/net/net_rand.c @@ -0,0 +1,68 @@ +/*
- 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: ");
mh? this shouldn't be here anymore should it?
- 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;
+}
is this really random? this conflicts with my patch (lib/rand.c) i'm trying to put into upstream.
diff --git a/net/net_rand.h b/net/net_rand.h new file mode 100644 index 0000000..c98db64 --- /dev/null +++ b/net/net_rand.h @@ -0,0 +1,26 @@ +/*
- Copied from LiMon - BOOTP.
- Copyright 1994, 1995, 2000 Neil Russell.
- (See License)
- Copyright 2000 Paolo Scaffardi
- */
+#ifndef __NET_RAND_H__ +#define __NET_RAND_H__
+#define RAND_MAX 0xffffffff
+/*
- Seed the random number generator using the eth0 MAC address
- */
+void srand_mac(void);
+/*
- Get a random number (after seeding with MAC address)
- @return random number
- */
+unsigned long rand(void);
+#endif /* __NET_RAND_H__ */
if this is unconditionally included, my patch fails because there are multiple declarations of rand().
Can we unify this with my patch, which is based on a paper about PRNGs? Eg. use the rand()/srand() from my patch and create an srand_mac() inline function which uses srand() from lib/rand.c ?
Joe, if that is ok, i'll put that into the next version of my "lsxl: add support for lschlv2 and lsxhl" patch series.