Bug 428548: Restrict the total number of safebrowsing update requests per hour. r=tony, a=mconnor

toolkit/components/url-classifier/content/listmanager.js

@@ -98,6 +98,8 @@ function PROT_ListManager() {
 
   this.requestBackoff_ = new RequestBackoff(3 /* num errors */,
                                    10*60*1000 /* error time, 10min */,
+                                            4 /* num requests */,
+                                   60*60*1000 /* request time, 60 min */,
                                    60*60*1000 /* backoff interval, 60min */,
                                    6*60*60*1000 /* max backoff, 6hr */);
 
@@ -450,6 +452,8 @@ PROT_ListManager.prototype.makeUpdateRequest_ = function(tableData) {
     return;
   }
 
+  this.requestBackoff_.noteRequest();
+
   if (!streamer.downloadUpdates(tableList,
                                 request,
                                 this.keyManager_.getClientKey(),

toolkit/components/url-classifier/content/request-backoff.js

@@ -52,16 +52,26 @@ const HTTP_TEMPORARY_REDIRECT    = 307;
  * @param maxErrors Number the number of errors needed to trigger backoff
  * @param errorPeriod Number time (ms) in which maxErros have to occur to
  *     trigger the backoff behavior
+ * @param maxRequests Number the number of requests needed to trigger backoff
+ * @param requestPeriod Number time (ms) in which maxRequests have to occur to
+ *     trigger the backoff behavior
  * @param timeoutIncrement Number time (ms) the starting timeout period
  *     we double this time for consecutive errors
  * @param maxTimeout Number time (ms) maximum timeout period
  */
-function RequestBackoff(maxErrors, errorPeriod, timeoutIncrement, maxTimeout) {
+function RequestBackoff(maxErrors, errorPeriod,
+                        maxRequests, requestPeriod,
+                        timeoutIncrement, maxTimeout) {
   this.MAX_ERRORS_ = maxErrors;
   this.ERROR_PERIOD_ = errorPeriod;
+  this.MAX_REQUESTS_ = maxRequests;
+  this.REQUEST_PERIOD_ = requestPeriod;
   this.TIMEOUT_INCREMENT_ = timeoutIncrement;
   this.MAX_TIMEOUT_ = maxTimeout;
 
+  // Queue of ints keeping the time of all requests
+  this.requestTimes_ = [];
+
   // Queue of ints keeping the time of errors.
   this.errorTimes_ = [];
   this.errorTimeout_ = 0;
@@ -83,7 +93,22 @@ RequestBackoff.prototype.reset = function() {
  * Check to see if we can make a request.
  */
 RequestBackoff.prototype.canMakeRequest = function() {
-  return Date.now() > this.nextRequestTime_;
+  var now = Date.now();
+  if (now <= this.nextRequestTime_) {
+    return false;
+  }
+
+  return (this.requestTimes_.length < this.MAX_REQUESTS_ ||
+          (now - this.requestTimes_[0]) > this.REQUEST_PERIOD_);
+}
+
+RequestBackoff.prototype.noteRequest = function() {
+  var now = Date.now();
+  this.requestTimes_.push(now);
+
+  // We only care about keeping track of MAX_REQUESTS
+  if (this.requestTimes_.length > this.MAX_REQUESTS_)
+    this.requestTimes_.shift();
 }
 
 /**
@@ -131,67 +156,3 @@ RequestBackoff.prototype.isErrorStatus = function(status) {
           HTTP_TEMPORARY_REDIRECT == status);
 }
 
-#ifdef 0
-// Some unittests (e.g., paste into JS shell)
-var jslib = Cc["@mozilla.org/url-classifier/jslib;1"].
-            getService().wrappedJSObject;
-var _Datenow = jslib.Date.now;
-function setNow(time) {
-  jslib.Date.now = function() {
-    return time;
-  }
-}
-
-// 2 errors, 5ms time period, 5ms backoff interval, 20ms max delay
-var rb = new jslib.RequestBackoff(2, 5, 5, 20);
-setNow(1);
-rb.noteServerResponse(200)
-if (!rb.canMakeRequest()) throw "expected ok";
-
-setNow(2);
-rb.noteServerResponse(500);
-if (!rb.canMakeRequest()) throw "expected ok";
-
-setNow(3);
-rb.noteServerResponse(200)
-if (!rb.canMakeRequest()) throw "expected ok";
-
-// Trigger backoff
-setNow(4);
-rb.noteServerResponse(502)
-if (rb.canMakeRequest()) throw "expected failed";
-if (rb.nextRequestTime_ != 9) throw "wrong next request time";
-
-// Trigger backoff again
-setNow(10);
-if (!rb.canMakeRequest()) throw "expected ok";
-rb.noteServerResponse(503)
-if (rb.canMakeRequest()) throw "expected failed";
-if (rb.nextRequestTime_ != 25) throw "wrong next request time";
-
-// Trigger backoff a third time and hit max timeout
-setNow(30);
-if (!rb.canMakeRequest()) throw "expected ok";
-rb.noteServerResponse(302)
-if (rb.canMakeRequest()) throw "expected failed";
-if (rb.nextRequestTime_ != 50) throw "wrong next request time";
-
-// Request goes through
-setNow(100);
-if (!rb.canMakeRequest()) throw "expected ok";
-rb.noteServerResponse(200)
-if (!rb.canMakeRequest()) throw "expected ok";
-if (rb.nextRequestTime_ != 0) throw "wrong next request time";
-
-// Another error (shouldn't trigger backoff)
-setNow(101);
-rb.noteServerResponse(500);
-if (!rb.canMakeRequest()) throw "expected ok";
-
-// Another error, but not in ERROR_PERIOD, so it should be ok
-setNow(107);
-rb.noteServerResponse(500);
-if (!rb.canMakeRequest()) throw "expected ok";
-
-jslib.Date.now = _Datenow;
-#endif