Add histogram for key exchange strength

net/socket/ssl_client_socket_pool.cc

Index: net/socket/ssl_client_socket_pool.cc
diff --git a/net/socket/ssl_client_socket_pool.cc b/net/socket/ssl_client_socket_pool.cc
index a80df57d0be4a8d084e62c5d09f1040ee458c962..babd137207e5364a8c80e552ae852c64793ccf65 100644
--- a/net/socket/ssl_client_socket_pool.cc
+++ b/net/socket/ssl_client_socket_pool.cc
@@ -21,6 +21,7 @@
 #include "net/socket/ssl_client_socket.h"
 #include "net/socket/transport_client_socket_pool.h"
 #include "net/ssl/ssl_cert_request_info.h"
+#include "net/ssl/ssl_cipher_suite_names.h"
 #include "net/ssl/ssl_connection_status_flags.h"
 #include "net/ssl/ssl_info.h"
 
@@ -371,9 +372,35 @@ int SSLConnectJob::DoSSLConnectComplete(int result) {
                                                     ssl_info.connection_status),
                               SSL_CONNECTION_VERSION_MAX);
 
-    UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_CipherSuite",
-                                SSLConnectionStatusToCipherSuite(
-                                    ssl_info.connection_status));
+    uint16 cipher_suite =
+        SSLConnectionStatusToCipherSuite(ssl_info.connection_status);
+    UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_CipherSuite", cipher_suite);
+
+    const char *str, *cipher_str, *mac_str;
+    bool is_aead;
+    SSLCipherSuiteToStrings(&str, &cipher_str, &mac_str, &is_aead,
+                            cipher_suite);
+    // UMA_HISTOGRAM_... macros cache the Histogram instance and thus only work

[agl, 2015/08/26 17:28:02]

What decision are we going to make with this data?

Also, we don't support DH or ECDH cipher suites.

[sigbjorn, 2015/08/27 14:51:38]

For now, as long as DH is still supported (for however long that may be), it
will help make decisions about how to treat DH, in particular DH 1024. It will
also give data points which may be used in determining when and how to deprecate
DH.
For RSA, the information is available elsewhere, and already histogrammed. I
don't know what RSA information is used for, but presumably there is a need for
it.
This information is currently not available elsewhere for ECDH. The distribution
of curves is not equal, knowing which are used is interesting information, even
if no actions are yet planned based on the knowledge.

In general, this is raw data, available for use in whichever way is fit.
Removed

+    // if the histogram name is constant, so don't generate it dynamically.
+    if (strncmp(str, "RSA", 3) == 0) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_KeyExchange.RSA",
+                                  ssl_info.key_exchange_info);
+    } else if (strncmp(str, "DHE", 3) == 0) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_KeyExchange.DHE",
+                                  ssl_info.key_exchange_info);
+    } else if (strncmp(str, "DH", 2) == 0) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_KeyExchange.DH",
+                                  ssl_info.key_exchange_info);
+    } else if (strncmp(str, "ECDHE", 5) == 0) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_KeyExchange.ECDHE",
+                                  ssl_info.key_exchange_info);
+    } else if (strncmp(str, "ECDH", 4) == 0) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_KeyExchange.ECDH",
+                                  ssl_info.key_exchange_info);
+    } else {
+      UMA_HISTOGRAM_SPARSE_SLOWLY("Net.SSL_KeyExchange.Unknown",
+                                  ssl_info.key_exchange_info);
+    }
 
     if (ssl_info.handshake_type == SSLInfo::HANDSHAKE_RESUME) {
       UMA_HISTOGRAM_CUSTOM_TIMES("Net.SSL_Connection_Latency_Resume_Handshake",