asserts

[oweals/gnunet.git] / src / util / crypto_random.c

diff --git a/src/util/crypto_random.c b/src/util/crypto_random.c
index b56523a4685a3810eb67f4584ccb5cf1449cce1f..35dafd071b98afcda77b4b4d95c19927e645aeaf 100644 (file)
--- a/src/util/crypto_random.c
+++ b/src/util/crypto_random.c
@@ -30,11 +30,26 @@
 #include <gcrypt.h>
 
 /**
+ * Create a cryptographically weak pseudo-random number in the interval of 0 to 1.
+ * 
+ * @return number between 0 and 1.
+ */
+static double
+weak_random ()
+{
+  return ((double) RANDOM () / RAND_MAX);
+}
+
+
+/**
+ * Produce a random value.
+ *
+ * @param mode desired quality of the random number
+ * @param i the upper limit (exclusive) for the random number
  * @return a random value in the interval [0,i[.
  */
 uint32_t
-GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, 
-                         uint32_t i)
+GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i)
 {
 #ifdef gcry_fast_random_poll
   static unsigned int invokeCount;
@@ -51,13 +66,12 @@ GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode,
         gcry_fast_random_poll ();
 #endif
       gcry_randomize ((unsigned char *) &ret,
-                      sizeof (uint32_t),
-                     GCRY_STRONG_RANDOM);
+                      sizeof (uint32_t), GCRY_STRONG_RANDOM);
       return ret % i;
     }
   else
     {
-      ret = i * ((double) RANDOM () / RAND_MAX);
+      ret = i * weak_random ();
       if (ret >= i)
         ret = i - 1;
       return ret;
@@ -97,26 +111,29 @@ GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n)
 
 /**
  * Random on unsigned 64-bit values.
+ *
+ *
+ * @param mode desired quality of the random number
+ * @param max value returned will be in range [0,max) (exclusive)
+ * @return random 64-bit number
  */
 uint64_t
-GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode,
-                          uint64_t u)
+GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max)
 {
   uint64_t ret;
 
-  GNUNET_assert (u > 0);
+  GNUNET_assert (max > 0);
   if (mode == GNUNET_CRYPTO_QUALITY_STRONG)
     {
       gcry_randomize ((unsigned char *) &ret,
-                      sizeof (uint64_t),
-                     GCRY_STRONG_RANDOM);
-      return ret % u;
+                      sizeof (uint64_t), GCRY_STRONG_RANDOM);
+      return ret % max;
     }
   else
     {
-      ret = u * ((double) RANDOM () / RAND_MAX);
-      if (ret >= u)
-        ret = u - 1;
+      ret = max * weak_random ();
+      if (ret >= max)
+        ret = max - 1;
       return ret;
     }
 }
@@ -135,8 +152,7 @@ GNUNET_CRYPTO_random_disable_entropy_gathering ()
 /**
  * Initializer
  */
-void __attribute__ ((constructor))
-GNUNET_util_random_init()
+void __attribute__ ((constructor)) GNUNET_util_random_init ()
 {
   SRANDOM (time (NULL));
 }