net: Move MAC-seeded rand out of bootp.c

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>
Acked-by: Simon Glass <sjg@chromium.org>

1 files changed, 68 insertions, 0 deletions

diff --git a/net/net_rand.c b/net/net_rand.c
new file mode 100644
index 00000000000..5387abadcff
--- /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: ");
+	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;
+}