[U-Boot] [PATCH v3 02/21] net: Move MAC-seeded rand out of bootp.c
Joe Hershberger
joe.hershberger at ni.com
Wed May 23 19:57:58 CEST 2012
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 at ni.com>
Cc: Joe Hershberger <joe.hershberger at 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/Makefile b/net/Makefile
index 0544f6b..5901046 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -31,6 +31,7 @@ COBJS-$(CONFIG_CMD_NET) += bootp.o
COBJS-$(CONFIG_CMD_DNS) += dns.o
COBJS-$(CONFIG_CMD_NET) += eth.o
COBJS-$(CONFIG_CMD_NET) += net.o
+COBJS-$(CONFIG_BOOTP_RANDOM_DELAY) += net_rand.o
COBJS-$(CONFIG_CMD_NFS) += nfs.o
COBJS-$(CONFIG_CMD_RARP) += rarp.o
COBJS-$(CONFIG_CMD_SNTP) += sntp.o
diff --git a/net/bootp.c b/net/bootp.c
index d0a7da2..0185e56 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -12,6 +12,7 @@
#include <command.h>
#include <net.h>
#include "bootp.h"
+#include "net_rand.h"
#include "tftp.h"
#include "nfs.h"
#ifdef CONFIG_STATUS_LED
@@ -37,9 +38,6 @@
ulong BootpID;
int BootpTry;
-#ifdef CONFIG_BOOTP_RANDOM_DELAY
-ulong seed1, seed2;
-#endif
#if defined(CONFIG_CMD_DHCP)
dhcp_state_t dhcp_state = INIT;
@@ -584,6 +582,9 @@ BootpRequest(void)
uchar *pkt, *iphdr;
struct Bootp_t *bp;
int ext_len, pktlen, iplen;
+#ifdef CONFIG_BOOTP_RANDOM_DELAY
+ ulong i, rand_ms;
+#endif
bootstage_mark_name(BOOTSTAGE_ID_BOOTP_START, "bootp_start");
#if defined(CONFIG_CMD_DHCP)
@@ -591,60 +592,16 @@ BootpRequest(void)
#endif
#ifdef CONFIG_BOOTP_RANDOM_DELAY /* Random BOOTP delay */
- unsigned char bi_enetaddr[6];
- int reg;
- ulong tst1, tst2, sum, m_mask, m_value = 0;
-
- if (BootpTry == 0) {
- /* 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;
- }
+ if (BootpTry == 0)
+ srand_mac();
- 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;
- }
-
- /* Random Number Generator */
- for (reg = 0; reg <= 0; reg++) {
- sum = seed1 + seed2;
- if (sum < seed1 || sum < seed2)
- sum++;
- seed2 = seed1;
- seed1 = sum;
-
- if (BootpTry <= 2) { /* Start with max 1024 * 1ms */
- sum = sum >> (22-BootpTry);
- } else { /*After 3rd BOOTP request max 8192 * 1ms */
- sum = sum >> 19;
- }
- }
+ if (BootpTry <= 2) /* Start with max 1024 * 1ms */
+ rand_ms = rand() >> (22 - BootpTry);
+ else /* After 3rd BOOTP request max 8192 * 1ms */
+ rand_ms = rand() >> 19;
- printf("Random delay: %ld ms...\n", sum);
- for (reg = 0; reg < sum; reg++)
+ printf("Random delay: %ld ms...\n", rand_ms);
+ for (i = 0; i < rand_ms; i++)
udelay(1000); /*Wait 1ms*/
#endif /* CONFIG_BOOTP_RANDOM_DELAY */
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 at 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;
+}
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__ */
--
1.6.0.2
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