Record errors that trigger a data reduction proxy bypass

net/http/http_response_headers.cc

Index: net/http/http_response_headers.cc
diff --git a/net/http/http_response_headers.cc b/net/http/http_response_headers.cc
index 7ecf37a2352704f02685e9012c64a04c296999bd..7c36dbd24febe70ab57f414505c18a46e6e0b9d6 100644
--- a/net/http/http_response_headers.cc
+++ b/net/http/http_response_headers.cc
@@ -1504,6 +1504,17 @@ HttpResponseHeaders::GetDataReductionProxyBypassEventType(
     // response is to minimize information transfer, a sender in general
     // should not generate representation metadata other than Cache-Control,
     // Content-Location, Date, ETag, Expires, and Vary.
+
+    // A Via header might also not be present in a 4xx response. If there is
+    // evidence that the 4xx response was generated by the proxy, bypass it.
+    if (response_code() >= HTTP_BAD_REQUEST &&
+        response_code() < HTTP_INTERNAL_SERVER_ERROR) {
+      if (HasHeaderValue("Server", "GFE/2.0"))
+        return ProxyService::CLIENT_ERROR_BYPASS;
+      // Do not bypass other 4xx responses on an incorrect or missing Via

[Matt Welsh, 2014/05/23 23:56:30]

Wait, according to your doc, you should be doing a 1-5 minute bypass in the case
of a 4xx with a missing Via and a missing GFE header.

[bengr, 2014/05/24 01:22:02]

Discussed offline. Changed.

+      // header.
+      return ProxyService::BYPASS_EVENT_TYPE_MAX;
+    }
     return ProxyService::MISSING_VIA_HEADER;
   }
   // There is no bypass event.