Anti-DDoS enhancements: Log to net log, UMA stats, improved policy.

net/base/backoff_entry.cc

Index: net/base/backoff_entry.cc
diff --git a/net/base/backoff_entry.cc b/net/base/backoff_entry.cc
index e7b7b558b70fc0e839044675f5af2412d5f86fed..dfde51d8dc153dd0d5020232b1575df15a552502 100644
--- a/net/base/backoff_entry.cc
+++ b/net/base/backoff_entry.cc
@@ -51,12 +51,12 @@ void BackoffEntry::InformOfRequest(bool succeeded) {
     // release time, further requests will then need to wait the delay caused
     // by the 2 failures.
     exponential_backoff_release_time_ = std::max(
-        GetTimeNow(), exponential_backoff_release_time_);
+        ImplGetTimeNow(), exponential_backoff_release_time_);
   }
 }
 
 bool BackoffEntry::ShouldRejectRequest() const {
-  return exponential_backoff_release_time_ > GetTimeNow();
+  return exponential_backoff_release_time_ > ImplGetTimeNow();
 }
 
 base::TimeTicks BackoffEntry::GetReleaseTime() const {
@@ -71,7 +71,7 @@ bool BackoffEntry::CanDiscard() const {
   if (policy_->entry_lifetime_ms == -1)
     return false;
 
-  base::TimeTicks now = GetTimeNow();
+  base::TimeTicks now = ImplGetTimeNow();
 
   int64 unused_since_ms =
       (now - exponential_backoff_release_time_).InMilliseconds();
@@ -92,7 +92,16 @@ bool BackoffEntry::CanDiscard() const {
   return unused_since_ms >= policy_->entry_lifetime_ms;
 }
 
-base::TimeTicks BackoffEntry::GetTimeNow() const {
+void BackoffEntry::Reset() {
+  failure_count_ = 0;
+  exponential_backoff_release_time_ = ImplGetTimeNow();
+}
+
+int BackoffEntry::failure_count() const {
+  return failure_count_;
+}
+
+base::TimeTicks BackoffEntry::ImplGetTimeNow() const {
   return base::TimeTicks::Now();
 }
 
@@ -102,7 +111,7 @@ base::TimeTicks BackoffEntry::CalculateReleaseTime() const {
   if (effective_failure_count == 0) {
     // Never reduce previously set release horizon, e.g. due to Retry-After
     // header.
-    return std::max(GetTimeNow(), exponential_backoff_release_time_);
+    return std::max(ImplGetTimeNow(), exponential_backoff_release_time_);
   }
 
   // The delay is calculated with this formula:
@@ -119,8 +128,9 @@ base::TimeTicks BackoffEntry::CalculateReleaseTime() const {
 
   // Never reduce previously set release horizon, e.g. due to Retry-After
   // header.
-  return std::max(GetTimeNow() + base::TimeDelta::FromMilliseconds(delay_int),
-                  exponential_backoff_release_time_);
+  return std::max(
+      ImplGetTimeNow() + base::TimeDelta::FromMilliseconds(delay_int),
+      exponential_backoff_release_time_);
 }
 
 }  // namespace net