QUIC - Record reject reasons for CHLO message.

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 b37befea03e661e50600e9ec3b5b2136cac00d8d..777b8c5e13af2c6fd7f98ed1dde6119f604d1200 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/sparse_histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "net/quic/crypto/cert_compressor.h"
@@ -592,16 +593,45 @@ QuicErrorCode QuicCryptoClientConfig::ProcessRejection(
   COMPILE_ASSERT(sizeof(QuicTag) == sizeof(uint32), header_out_of_sync);
   if (rej.GetTaglist(kRREJ, &reject_reasons,
                      &num_reject_reasons) == QUIC_NO_ERROR) {
-#if defined(DEBUG)
+    uint32 packed_error = 0;
     for (size_t i = 0; i < num_reject_reasons; ++i) {
-      DVLOG(1) << "Reasons for rejection: " << reject_reasons[i];
+      HandshakeFailureReason reason =
+          static_cast<HandshakeFailureReason>(reject_reasons[i]);
+      packed_error |= RejectReasonToPackedError(reason);
     }
-#endif
+    UMA_HISTOGRAM_SPARSE_SLOWLY("Net.QuicClientHelloRejectReasons",
+                                packed_error);
   }
 
   return QUIC_NO_ERROR;
 }
 
+uint32 QuicCryptoClientConfig::RejectReasonToPackedError(
+    HandshakeFailureReason reason) {
+  enum RejectReasonShift {
+    CLIENT_NONCE_SHIFT = 5,
+    SERVER_NONCE_SHIFT = 10,
+    SERVER_CONFIG_SHIFT = 15,
+    SOURCE_ADDRESS_TOKEN_SHIFT = 20,

[Ryan Hamilton, 2014/06/21 03:02:29]

If you were really excited, you could add some compile_asserts that these values
are large enough to include the number of codes in each category.  Probably not
worth it, though.

[ramant (doing other things), 2014/06/23 17:27:35]

Done.

+  };
+
+  if (reason < CLIENT_NONCE_UNKNOWN_FAILURE) {
+    return reason;
+  }
+  if (reason < SERVER_NONCE_INVALID_FAILURE) {
+    return (reason - CLIENT_NONCE_UNKNOWN_FAILURE + 1) << CLIENT_NONCE_SHIFT;
+  }
+  if (reason < SERVER_CONFIG_INCHOATE_HELLO_FAILURE) {
+    return (reason - SERVER_NONCE_INVALID_FAILURE + 1)  << SERVER_NONCE_SHIFT;
+  }
+  if (reason < SOURCE_ADDRESS_TOKEN_INVALID_FAILURE) {
+    return (reason - SERVER_CONFIG_INCHOATE_HELLO_FAILURE + 1) <<
+        SERVER_CONFIG_SHIFT;
+  }
+  return (reason - SOURCE_ADDRESS_TOKEN_INVALID_FAILURE + 1) <<
+      SOURCE_ADDRESS_TOKEN_SHIFT;
+}
+
 QuicErrorCode QuicCryptoClientConfig::ProcessServerHello(
     const CryptoHandshakeMessage& server_hello,
     QuicConnectionId connection_id,