Add histogram to track NPN/ALPN.

net/socket/ssl_client_socket.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/socket/ssl_client_socket.h"
 
 #include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/strings/string_util.h"
 #include "crypto/ec_private_key.h"
 #include "net/base/host_port_pair.h"
 #include "net/ssl/channel_id_service.h"
 #include "net/ssl/ssl_config_service.h"
 
 namespace net {
 
 SSLClientSocket::SSLClientSocket()
     : was_npn_negotiated_(false),
       was_spdy_negotiated_(false),
       protocol_negotiated_(kProtoUnknown),
       channel_id_sent_(false),
       signed_cert_timestamps_received_(false),
-      stapled_ocsp_response_received_(false) {
+      stapled_ocsp_response_received_(false),
+      negotiation_extension_(kExtensionUnknown) {
 }
 
 // static
 NextProto SSLClientSocket::NextProtoFromString(
     const std::string& proto_string) {
   if (proto_string == "http1.1" || proto_string == "http/1.1") {
     return kProtoHTTP11;
   } else if (proto_string == "spdy/2") {
     return kProtoDeprecatedSPDY2;
   } else if (proto_string == "spdy/3") {
@@ skipping 84 matching lines @@
 }
 
 bool SSLClientSocket::set_was_spdy_negotiated(bool negotiated) {
   return was_spdy_negotiated_ = negotiated;
 }
 
 void SSLClientSocket::set_protocol_negotiated(NextProto protocol_negotiated) {
   protocol_negotiated_ = protocol_negotiated;
 }
 
+void SSLClientSocket::set_negotiation_extension(
+    SSLNegotiationExtension negotiation_extension) {
+  negotiation_extension_ = negotiation_extension;
+}
+
 bool SSLClientSocket::WasChannelIDSent() const {
   return channel_id_sent_;
 }
 
 void SSLClientSocket::set_channel_id_sent(bool channel_id_sent) {
   channel_id_sent_ = channel_id_sent;
 }
 
 void SSLClientSocket::set_signed_cert_timestamps_received(
     bool signed_cert_timestamps_received) {
@@ skipping 88 matching lines @@
     wire_protos.push_back(i->size());
     wire_protos.resize(wire_protos.size() + i->size());
     memcpy(&wire_protos[wire_protos.size() - i->size()],
            i->data(), i->size());
   }
   DCHECK_EQ(wire_protos.size(), wire_length);
 
   return wire_protos;
 }
 
+void SSLClientSocket::RecordNegotiationExtension() {
+  if (negotiation_extension_ == kExtensionUnknown)
+    return;
+  std::string proto;
+  SSLClientSocket::NextProtoStatus status = GetNextProto(&proto);
+  if (status == kNextProtoUnsupported)
+    return;
+  // Convert protocol into numerical value for histogram.
+  NextProto protocol_negotiated = SSLClientSocket::NextProtoFromString(proto);
+  base::HistogramBase::Sample sample =
+      static_cast<base::HistogramBase::Sample>(protocol_negotiated);
+  // In addition to the protocol negotiated, we want to record which TLS
+  // extension was used, and in case of NPN, whether there was overlap between
+  // server and client list of supported protocols.
+  if (negotiation_extension_ == kExtensionNPN) {
+    if (status == kNextProtoNoOverlap) {
+      sample += 1000;
+    } else {
+      sample += 500;

[davidben, 2014/10/03 17:55:07]

This is probably worth a comment in net/socket/next_proto.h that the values must
be below 500 now.

[Bence, 2014/10/10 15:26:10]

Done.

+    }
+  }

[davidben, 2014/10/03 17:55:07]

Nit: I'd put in an
  } else {
    DCHECK_EQ(kExtensionALPN, negotiation_extension_);
  }
just so you document that the other case is ALPN.

[Bence, 2014/10/10 15:26:10]

Done.

+  UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSLProtocolNegotiation", sample);
+}
+
 }  // namespace net