fixup

Author: ronag

lib/random-util.js

@@ -4,15 +4,31 @@
 
 const net = require('net');
 const tls = require('tls');
-const { randomFillMask } = require('./random-util');
 
 const PerMessageDeflate = require('./permessage-deflate');
 const { EMPTY_BUFFER } = require('./constants');
 const { isValidStatusCode } = require('./validation');
 const { mask: applyMask, toBuffer } = require('./buffer-util');
+const { randomBytes } = require('crypto');
 
 const mask = Buffer.alloc(4);
 
+const RANDOM_POOL_SIZE = 8192;
+const RANDOM_POOL_REFRESH = 1024;
+
+let randomPool = Buffer.alloc(RANDOM_POOL_SIZE);
+let randomPoolIdx = RANDOM_POOL_SIZE;
+let randomPending = true;
+
+function onRandomBytes (err, buf) {
+  randomPending = false;
+  if (!err) {
+    randomPool = buf;
+    randomPoolIdx = 0;
+  }
+}
+randomBytes(RANDOM_POOL_SIZE, onRandomBytes);
+
 /**
  * HyBi Sender implementation.
  */
@@ -81,13 +97,21 @@ class Sender {
 
     if (!options.mask) return [target, data];
 
-    randomFillMask(mask);
+    if (randomPool.length - randomPoolIdx < 4) {
+      randomPool = randomBytes(32);
+      randomPoolIdx = 0;
+    }
 
     target[1] |= 0x80;
-    target[offset - 4] = mask[0];
-    target[offset - 3] = mask[1];
-    target[offset - 2] = mask[2];
-    target[offset - 1] = mask[3];
+    target[offset - 4] = mask[0] = randomPool[randomPoolIdx++];
+    target[offset - 3] = mask[1] = randomPool[randomPoolIdx++];
+    target[offset - 2] = mask[2] = randomPool[randomPoolIdx++];
+    target[offset - 1] = mask[3] = randomPool[randomPoolIdx++];
+
+    if (randomPool.length - randomPoolIdx < RANDOM_POOL_REFRESH && !randomPending) {
+      randomPending = true;
+      randomBytes(RANDOM_POOL_SIZE, onRandomBytes);
+    }
 
     if (merge) {
       applyMask(data, mask, target, offset, data.length);