include support for a simple pseudo number generator

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

include/net.h

@@ -16,6 +16,7 @@
 #include <linux/types.h>
 #include <param.h>
 #include <malloc.h>
+#include <stdlib.h>
 #include <asm/byteorder.h>	/* for nton* / ntoh* stuff */
 
 

include/stdlib.h

@@ -0,0 +1,16 @@
+#ifndef __STDLIB_H
+#define __STDLIB_H
+
+#define RAND_MAX 32767
+
+/* return a pseudo-random integer in the range [0, RAND_MAX] */
+unsigned int rand(void);
+
+/* set the seed for rand () */
+void srand(unsigned int seed);
+
+/* fill a buffer with pseudo-random data */
+void get_random_bytes(char *buf, int len);
+
+
+#endif /* __STDLIB_H */

lib/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
 obj-y			+= glob.o
 obj-y			+= notifier.o
 obj-y			+= copy_file.o
+obj-y			+= random.o
 obj-y			+= lzo/
 obj-$(CONFIG_LZO_DECOMPRESS)		+= decompress_unlzo.o
 obj-$(CONFIG_PROCESS_ESCAPE_SEQUENCE)	+= process_escape_sequence.o

lib/random.c

@@ -0,0 +1,26 @@
+#include <common.h>
+#include <stdlib.h>
+
+static unsigned int random_seed;
+
+#if RAND_MAX > 32767
+#error this rand implementation is for RAND_MAX < 32678 only.
+#endif
+
+unsigned int rand(void)
+{
+	random_seed = random_seed * 1103515245 + 12345;
+	return (random_seed / 65536) % (RAND_MAX + 1);
+}
+
+void srand(unsigned int seed)
+{
+	random_seed = seed;
+}
+
+void get_random_bytes(char *buf, int len)
+{
+	while (len--)
+		*buf++ = rand() % 256;
+}
+