From c59bf12270a66718595d4aeef78ca1ba4636b9ca Mon Sep 17 00:00:00 2001
From: asterix <asterix@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Thu, 8 Feb 2007 17:18:01 +0000
Subject: [PATCH] Write add_data and stir function. Typos

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@770 38d2e660-2303-0410-9eaa-f027e97ec537
---
 algos/randpool.c | 80 +++++++++++++++++++++++++++++++++++++++++++++---
 algos/randpool.h |  5 ++-
 2 files changed, 80 insertions(+), 5 deletions(-)

diff --git a/algos/randpool.c b/algos/randpool.c
index b7f090b9..92751dd7 100755
--- a/algos/randpool.c
+++ b/algos/randpool.c
@@ -13,6 +13,9 @@
 
 /*#*
  *#* $Log$
+ *#* Revision 1.4  2007/02/08 17:18:00  asterix
+ *#* Write add_data and stir function. Typos
+ *#*
  *#* Revision 1.3  2007/02/08 14:25:29  asterix
  *#* Write static funcion push_byte.
  *#*
@@ -24,11 +27,11 @@
 #include <string.h>            //memset(), memcpy();
 #include <cfg/compiler.h>
 #include <cfg/debug.h>        //ASSERT()
+#include <drv/timer.h>        //timer_clock();
+
+#include <stdio.h>   //sprintf();
+
 
-static void stir(EntrPool *pool)
-{
-	
-}
 
 /*
  * Insert bytes in entropy pool, making a XOR of bytes present
@@ -56,16 +59,85 @@ static void push_byte(EntrPool *pool, void *_byte)
 	pool->pool_pos_add  =  i; // Update a insert bytes.
 }
 
+/* 
+ * This function stir entropy pool with MD2 function hash.
+ *
+ */
+static void stir(EntrPool *pool)
+{
+	size_t entropy = pool->entropy; //Save current calue of entropy.
+	Md2Context context;
+	uint8_t tmp_buf[(sizeof(size_t) * 2) + sizeof(int)];  //Temporary buffer.
+
+	md2_init(&context);
+	
+	add_data(pool, "", 0);
+		
+	for (int i = 0; i < (CONFIG_SIZE_ENTROPY_POOL / CONFIG_MD2_BLOCK_LEN); i++)
+	{
+		sprintf(tmp_buf, "%x%x%x",pool->counter, i, pool->pool_pos_add); 
+		
+		/*
+		 * Hash with MD2 algorithm the entropy pool.
+		 */
+		md2_update(&context, pool->pool_entropy, CONFIG_SIZE_ENTROPY_POOL);
+		
+		md2_update(&context, tmp_buf, CONFIG_SIZE_ENTROPY_POOL);
+
+		push_byte(pool, md2_end(&context)); //Insert a message digest in entropy pool.
+
+		pool->counter = (pool->counter + 1) & 0xFFFFFFFF; //Update a counter modulo 4.
+	
+	}
+	
+	/*Insert in pool the difference between a two call of this function (see above).*/
+	add_data(pool, "", 0); 
+	
+	pool->entropy = entropy; //Restore old value of entropy. We haven't add entropy.
+}
+
+
 void init_pool(EntrPool *pool)
 {
 	
 	memset(pool, 0, sizeof(EntrPool));
 
+	//TODO: inizializzazione del timer di sistema.
+
 }
 
+/**
+ * Add n_bit of  entropy in entropy pool.
+ */
 void add_data(EntrPool *pool, void *data, size_t n_bit)
 {
+	uint32_t event = timer_clock();
+	uint32_t delta;
+
+	push_byte(pool, data); //Insert data to entropy pool. 
+	
+	push_byte(pool, "\xaa\xaa\xaa\xaa"); // ??
+
+	/*Difference of time between a two accese to entropy pool.*/
+	delta = event - pool->last_counter;
+	
+	push_byte(pool, &delta);
+	
+	delta = delta & 0xff;
+	
+	push_byte(pool, &delta);
 
+	/*
+	 * Count of number entropy bit add with delta.
+	 */
+	while(delta) 
+	{
+		delta >>= 1;
+		n_bit++;
+	}
+	
+	pool->entropy = n_bit;      //Update a entropy of the pool.
+	pool->last_counter = event;
 }
 
 size_t pool_size(EntrPool *pool)
diff --git a/algos/randpool.h b/algos/randpool.h
index 02daafa2..e996fa3c 100755
--- a/algos/randpool.h
+++ b/algos/randpool.h
@@ -14,6 +14,9 @@
 
 /*#*
  *#* $Log$
+ *#* Revision 1.4  2007/02/08 17:18:01  asterix
+ *#* Write add_data and stir function. Typos
+ *#*
  *#* Revision 1.3  2007/02/08 14:25:56  asterix
  *#* Typos.
  *#*
@@ -36,7 +39,7 @@
  */
 typedef struct EntrPool 
 {
-	size_t entropy;                                  ///< Actual value of entropy.
+	size_t entropy;                                  ///< Actual value of entropy (In bit).
 	size_t pool_pos_add;                             ///< Size of byte insert in entropy pool.
 	size_t pool_pos_get;                             ///< Size of byte take in entropy pool.
 	size_t counter;                                  ///< Counter.
-- 
2.25.1