QUIC - Track the reason for sending InchoateClientHello in UMA

net/quic/crypto/quic_crypto_client_config.cc

 // Copyright 2013 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/quic/crypto/quic_crypto_client_config.h"
 
+#include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "net/quic/crypto/cert_compressor.h"
 #include "net/quic/crypto/chacha20_poly1305_encrypter.h"
 #include "net/quic/crypto/channel_id.h"
 #include "net/quic/crypto/common_cert_set.h"
 #include "net/quic/crypto/crypto_framer.h"
 #include "net/quic/crypto/crypto_utils.h"
 #include "net/quic/crypto/curve25519_key_exchange.h"
 #include "net/quic/crypto/key_exchange.h"
 #include "net/quic/crypto/p256_key_exchange.h"
 #include "net/quic/crypto/proof_verifier.h"
 #include "net/quic/crypto/quic_encrypter.h"
 #include "net/quic/quic_utils.h"
 
 using base::StringPiece;
 using std::find;
 using std::make_pair;
 using std::map;
 using std::string;
 using std::vector;
 
 namespace net {
 
+namespace {
+
+enum ServerConfigState {
+  // WARNING: Do not change the numerical values of any of server config state.
+  // Do not remove deprecated server config states - just comment them as
+  // deprecated.
+  SERVER_CONFIG_EMPTY = 0,
+  SERVER_CONFIG_INVALID = 1,
+  SERVER_CONFIG_CORRUPTED = 2,
+  SERVER_CONFIG_EXPIRED = 3,
+
+  // NOTE: Add new server config states only immediately above this line. Make
+  // sure to update the QuicServerConfigState enum in
+  // tools/metrics/histograms/histograms.xml accordingly.
+  SERVER_CONFIG_COUNT
+};
+
+void RecordServerConfigState(ServerConfigState server_config_state) {
+  UMA_HISTOGRAM_ENUMERATION("Net.QuicClientHelloServerConfigState",
+                            server_config_state, SERVER_CONFIG_COUNT);
+}
+
+}  // namespace
+
 QuicCryptoClientConfig::QuicCryptoClientConfig()
     : disable_ecdsa_(false) {}
 
 QuicCryptoClientConfig::~QuicCryptoClientConfig() {
   STLDeleteValues(&cached_states_);
 }
 
 QuicCryptoClientConfig::CachedState::CachedState()
     : server_config_valid_(false),
       generation_counter_(0) {}
 
 QuicCryptoClientConfig::CachedState::~CachedState() {}
 
 bool QuicCryptoClientConfig::CachedState::IsComplete(QuicWallTime now) const {
-  if (server_config_.empty() || !server_config_valid_) {
+  if (server_config_.empty()) {
+    RecordServerConfigState(SERVER_CONFIG_EMPTY);
     return false;
   }
 
+  if (!server_config_valid_) {
+    RecordServerConfigState(SERVER_CONFIG_INVALID);
+    return false;
+  }
+
   const CryptoHandshakeMessage* scfg = GetServerConfig();
   if (!scfg) {
     // Should be impossible short of cache corruption.
     DCHECK(false);
+    RecordServerConfigState(SERVER_CONFIG_CORRUPTED);
     return false;
   }
 
   uint64 expiry_seconds;
   if (scfg->GetUint64(kEXPY, &expiry_seconds) != QUIC_NO_ERROR ||

[wtc, 2014/07/29 01:29:06]

Nit: scfg->GetUint64(kEXPY, &expiry_seconds) != QUIC_NO_ERROR is a separate
error condition. It means the server config has an absent or invalid kEXPY
value.

[ramant (doing other things), 2014/07/29 23:52:32]

Thanks Wan-Teh. Fixed it in https://codereview.chromium.org/431483002/

Done.

       now.ToUNIXSeconds() >= expiry_seconds) {
+    RecordServerConfigState(SERVER_CONFIG_EXPIRED);
     return false;
   }
 
   return true;
 }
 
 bool QuicCryptoClientConfig::CachedState::IsEmpty() const {
   return server_config_.empty();
 }
 
@@ skipping 729 matching lines @@
     return;
   }
 
   // Update canonical version to point at the "most recent" entry.
   canonical_server_map_[suffix_server_id] = server_id;
 
   server_state->InitializeFrom(*canonical_state);
 }
 
 }  // namespace net