QUIC - Track the reason for sending InchoateClientHello in UMA

net/quic/crypto/quic_crypto_client_config.cc

Index: net/quic/crypto/quic_crypto_client_config.cc
diff --git a/net/quic/crypto/quic_crypto_client_config.cc b/net/quic/crypto/quic_crypto_client_config.cc
index 33d5242b708bf82bfc6bd79b5109b520cee3b56d..27d9d060489b1fba4bde17090cf9d88ee06a1800 100644
--- a/net/quic/crypto/quic_crypto_client_config.cc
+++ b/net/quic/crypto/quic_crypto_client_config.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -29,6 +30,30 @@ 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) {}
 
@@ -43,7 +68,13 @@ QuicCryptoClientConfig::CachedState::CachedState()
 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;
   }
 
@@ -51,12 +82,14 @@ bool QuicCryptoClientConfig::CachedState::IsComplete(QuicWallTime now) const {
   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;
   }