Write randpool_getN.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@774 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/algos/randpool.c b/algos/randpool.c
index 69be610d3aa2c2c2363dc3e387ba647726d96f30..224fb4560303aba52bb7da032825c77358e1f072 100755 (executable)
--- a/algos/randpool.c
+++ b/algos/randpool.c
@@ -13,8 +13,8 @@
 
 /*#*
  *#* $Log$
- *#* Revision 1.7  2007/02/09 15:49:54  asterix
- *#* Fix bug in randpool_stir and randpool_add. Typos.
+ *#* Revision 1.8  2007/02/09 17:27:09  asterix
+ *#* Write randpool_getN.
  *#*
  *#* Revision 1.6  2007/02/09 09:24:38  asterix
  *#* Typos. Add data_len in randpool_add and n_byte in randpool_push pototypes.
@@ -27,12 +27,13 @@
 #include "randpool.h"
 #include "md2.h"
 
-#include <string.h>            //memset(), memcpy();
+#include <string.h>          //memset(), memcpy();
 #include <cfg/compiler.h>
-#include <cfg/debug.h>        //ASSERT()
-#include <drv/timer.h>        //timer_clock();
+#include <cfg/debug.h>       //ASSERT()
+#include <cfg/macros.h>      //MIN()
+#include <drv/timer.h>       //timer_clock();
 
-#include <stdio.h>            //sprintf();
+#include <stdio.h>           //sprintf();
 
 
 
@@ -60,42 +61,7 @@ static void randpool_push(EntropyPool *pool, void *_byte, size_t n_byte)
 }
 
 
-/**
- * Add n_bit of  entropy in entropy pool.
- */
-void randpool_add(EntropyPool *pool, void *data, size_t data_len, size_t entropy)
-{
-       ticks_t event = timer_clock();
-       uint32_t delta;
-       uint8_t sep[] = "\xaa\xaa\xaa\xaa";  // ??
-
-       randpool_push(pool, data, data_len); //Insert data to entropy pool.
-
-       randpool_push(pool, sep, strlen(sep)); // ??
-
-       /*Difference of time between a two accese to entropy pool.*/
-       delta = event - pool->last_counter;
-
-       randpool_push(pool, &delta, sizeof(delta));
-
-       delta = delta & 0xff;
-
-       randpool_push(pool, &delta, sizeof(delta));
-
-       /*
-        * Count of number entropy bit add with delta.
-        */
-       while(delta)
-       {
-               delta >>= 1;
-               entropy++;
-       }
-
-       pool->entropy += entropy;      //Update a entropy of the pool.
-       pool->last_counter = event;
-}
-
-/* \
+/*
  * This function stir entropy pool with MD2 function hash.
  *
  */
@@ -133,6 +99,41 @@ static void randpool_stir(EntropyPool *pool)
        pool->entropy = entropy; //Restore old value of entropy. We haven't add entropy.
 }
 
+/**
+ * Add n_bit of  entropy in entropy pool.
+ */
+void randpool_add(EntropyPool *pool, void *data, size_t data_len, size_t entropy)
+{
+       ticks_t event = timer_clock();
+       uint32_t delta;
+       uint8_t sep[] = "\xaa\xaa\xaa\xaa";  // ??
+
+       randpool_push(pool, data, data_len); //Insert data to entropy pool.
+
+       randpool_push(pool, sep, strlen(sep)); // ??
+
+       /*Difference of time between a two accese to entropy pool.*/
+       delta = event - pool->last_counter;
+
+       randpool_push(pool, &delta, sizeof(delta));
+
+       delta = delta & 0xff;
+
+       randpool_push(pool, &delta, sizeof(delta));
+
+       /*
+        * Count of number entropy bit add with delta.
+        */
+       while(delta)
+       {
+               delta >>= 1;
+               entropy++;
+       }
+
+       pool->entropy += entropy;      //Update a entropy of the pool.
+       pool->last_counter = event;
+}
+
 
 void randpool_init(EntropyPool *pool)
 {
@@ -158,8 +159,52 @@ void randpool_get(EntropyPool *pool, void *data, size_t n_byte)
 
 }
 
+/**
+ * Get n_byte from entropy pool. If n_byte is larger than number
+ * byte of entropy in entropy pool, rand_pool_getN continue
+ * to generate pseudocasual value from previous state of
+ * pool.
+ */
 void randpool_getN(EntropyPool *pool, void *data, size_t n_byte)
 {
+       Md2Context context;
+       size_t i = pool->pos_get;
+       int n = n_byte;
+       size_t len = MIN((size_t)CONFIG_MD2_BLOCK_LEN, n_byte);
+
+       /* Test if i + CONFIG_MD2_BLOCK_LEN  is inside of entropy pool.*/
+       ASSERT((CONFIG_MD2_BLOCK_LEN + i) < CONFIG_SIZE_ENTROPY_POOL);
+
+       md2_init(&context); 
+
+       while(n < 0)
+       {
+               /*Hash previous state of pool*/
+               md2_update(&context, &pool->pool_entropy[i], CONFIG_MD2_BLOCK_LEN);
+
+               memcpy(data, md2_end(&context), len);
+
+               n -= len; //Number of byte copied in data.
+
+               len = MIN(n, CONFIG_MD2_BLOCK_LEN);
+
+               i = (i + CONFIG_MD2_BLOCK_LEN) % CONFIG_SIZE_ENTROPY_POOL;
+
+               /* If we haven't more entropy pool to hash, we stir it.*/
+               if(i < CONFIG_MD2_BLOCK_LEN)
+               {
+                       randpool_stir(pool);
+                       i = pool->pos_get;
+               }
+       }
+       
+       pool->pos_get = i; //Current number of byte we get from pool.
+       
+       pool->entropy -= n_byte; //Update a entropy.
+
+       /*If we get all entropy entropy is 0*/
+       if(pool->entropy < 0) 
+               pool->entropy = 0;
 }
 
 bool randpool_save(void *data)