X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Frandom.c;h=c0bc659d19392430afd3d85d9100c735d6b73941;hb=003ce655b7116d18c86a74c50391e54990346931;hp=78a5916aa904731042567244b8777f5a29ce88cd;hpb=e519ea28d6da56330a46c5b1d7c3ad84a6c45536;p=sliver-openvswitch.git

diff --git a/lib/random.c b/lib/random.c
index 78a5916aa..c0bc659d1 100644
--- a/lib/random.c
+++ b/lib/random.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,10 @@
 #include <stdlib.h>
 #include <sys/time.h>
 
+#include "entropy.h"
+#include "hash.h"
+#include "ovs-thread.h"
+#include "timeval.h"
 #include "util.h"
 
 /* This is the 32-bit PRNG recommended in G. Marsaglia, "Xorshift RNGs",
@@ -29,32 +33,41 @@
  *
  * We use this PRNG instead of libc's rand() because rand() varies in quality
  * and because its maximum value also varies between 32767 and INT_MAX, whereas
- * we often want random numbers in the full range of uint32_t.  */
+ * we often want random numbers in the full range of uint32_t.
+ *
+ * This random number generator is intended for purposes that do not require
+ * cryptographic-quality randomness. */
 
 /* Current random state. */
-static uint32_t seed;
+DEFINE_STATIC_PER_THREAD_DATA(uint32_t, seed, 0);
 
 static uint32_t random_next(void);
 
 void
 random_init(void)
 {
-    if (!seed) {
+    uint32_t *seedp = seed_get();
+    while (!*seedp) {
         struct timeval tv;
+        uint32_t entropy;
+        pthread_t self;
 
-        if (gettimeofday(&tv, NULL) < 0) {
-            ovs_fatal(errno, "gettimeofday");
-        }
+        xgettimeofday(&tv);
+        get_entropy_or_die(&entropy, 4);
+        self = pthread_self();
 
-        seed = tv.tv_sec ^ tv.tv_usec;
-        if (!seed) {
-            /* A 'seed' of 0 is fatal to randomness--the random value will
-             * always be 0--so use the initial seed mentioned by Marsaglia. */
-            seed = UINT32_C(2463534242);
-        }
+        *seedp = (tv.tv_sec ^ tv.tv_usec ^ entropy
+                  ^ hash_bytes(&self, sizeof self, 0));
     }
 }
 
+void
+random_set_seed(uint32_t seed_)
+{
+    ovs_assert(seed_);
+    *seed_get() = seed_;
+}
+
 void
 random_bytes(void *p_, size_t n)
 {
@@ -73,17 +86,6 @@ random_bytes(void *p_, size_t n)
     }
 }
 
-uint8_t
-random_uint8(void)
-{
-    return random_uint32();
-}
-
-uint16_t
-random_uint16(void)
-{
-    return random_uint32();
-}
 
 uint32_t
 random_uint32(void)
@@ -92,18 +94,26 @@ random_uint32(void)
     return random_next();
 }
 
-int
-random_range(int max)
+uint64_t
+random_uint64(void)
 {
-    return random_uint32() % max;
+    uint64_t x;
+
+    random_init();
+
+    x = random_next();
+    x |= (uint64_t) random_next() << 32;
+    return x;
 }
 
 static uint32_t
 random_next(void)
 {
-    seed ^= seed << 13;
-    seed >>= 17;
-    seed ^= seed << 5;
+    uint32_t *seedp = seed_get_unsafe();
+
+    *seedp ^= *seedp << 13;
+    *seedp ^= *seedp >> 17;
+    *seedp ^= *seedp << 5;
 
-    return seed;
+    return *seedp;
 }