Add a new prefer_aes finch options for QUIC.

Review URL: https://codereview.chromium.org/1165283004

Cr-Commit-Position: refs/heads/master@{#333805}

chrome/browser/io_thread.cc

@@ -1174,6 +1174,7 @@ void IOThread::InitializeNetworkSessionParamsFromGlobals(
       &params->quic_enable_connection_racing);
   globals.quic_enable_non_blocking_io.CopyToIfSet(
       &params->quic_enable_non_blocking_io);
+  globals.quic_prefer_aes.CopyToIfSet(&params->quic_prefer_aes);
   globals.quic_disable_disk_cache.CopyToIfSet(
       &params->quic_disable_disk_cache);
   globals.quic_max_number_of_lossy_connections.CopyToIfSet(
@@ -1321,6 +1322,8 @@ void IOThread::ConfigureQuicGlobals(
         ShouldQuicEnableNonBlockingIO(quic_trial_params));
     globals->quic_disable_disk_cache.set(
         ShouldQuicDisableDiskCache(quic_trial_params));
+    globals->quic_prefer_aes.set(
+        ShouldQuicPreferAes(quic_trial_params));
     int max_number_of_lossy_connections = GetQuicMaxNumberOfLossyConnections(
         quic_trial_params);
     if (max_number_of_lossy_connections != 0) {
@@ -1531,6 +1534,13 @@ bool IOThread::ShouldQuicDisableDiskCache(
       GetVariationParam(quic_trial_params, "disable_disk_cache"), "true");
 }
 
+// static
+bool IOThread::ShouldQuicPreferAes(
+    const VariationParameters& quic_trial_params) {
+  return base::LowerCaseEqualsASCII(
+      GetVariationParam(quic_trial_params, "prefer_aes"), "true");
+}
+
 // static
 int IOThread::GetQuicMaxNumberOfLossyConnections(
     const VariationParameters& quic_trial_params) {

chrome/browser/io_thread.h

@@ -189,6 +189,7 @@ class IOThread : public content::BrowserThreadDelegate {
     Optional<bool> quic_enable_connection_racing;
     Optional<bool> quic_enable_non_blocking_io;
     Optional<bool> quic_disable_disk_cache;
+    Optional<bool> quic_prefer_aes;
     Optional<int> quic_max_number_of_lossy_connections;
     Optional<float> quic_packet_loss_threshold;
     Optional<int> quic_socket_receive_buffer_size;
@@ -375,6 +376,9 @@ class IOThread : public content::BrowserThreadDelegate {
   static bool ShouldQuicDisableDiskCache(
       const VariationParameters& quic_trial_params);
 
+  // Returns true if QUIC should prefer AES-GCN even without hardware support.
+  static bool ShouldQuicPreferAes(const VariationParameters& quic_trial_params);
+
   // Returns the maximum number of QUIC connections with high packet loss in a
   // row after which QUIC should be disabled.  Returns 0 if the default value
   // should be used.

chrome/browser/io_thread_unittest.cc

@@ -188,6 +188,7 @@ TEST_F(IOThreadTest, EnableQuicFromFieldTrialGroup) {
   EXPECT_FALSE(params.quic_enable_connection_racing);
   EXPECT_FALSE(params.quic_enable_non_blocking_io);
   EXPECT_FALSE(params.quic_disable_disk_cache);
+  EXPECT_FALSE(params.quic_prefer_aes);
   EXPECT_EQ(0, params.quic_max_number_of_lossy_connections);
   EXPECT_EQ(1.0f, params.quic_packet_loss_threshold);
   EXPECT_FALSE(IOThread::ShouldEnableQuicForDataReductionProxy());
@@ -363,6 +364,15 @@ TEST_F(IOThreadTest, QuicDisableDiskCache) {
   EXPECT_TRUE(params.quic_disable_disk_cache);
 }
 
+TEST_F(IOThreadTest, QuicPreferAes) {
+  field_trial_group_ = "Enabled";
+  field_trial_params_["prefer_aes"] = "true";
+  ConfigureQuicGlobals();
+  net::HttpNetworkSession::Params params;
+  InitializeNetworkSessionParams(&params);
+  EXPECT_TRUE(params.quic_prefer_aes);
+}
+
 TEST_F(IOThreadTest, QuicMaxNumberOfLossyConnectionsFieldTrialParams) {
   field_trial_group_ = "Enabled";
   field_trial_params_["max_number_of_lossy_connections"] = "5";

net/http/http_network_session.cc

@@ -98,6 +98,7 @@ HttpNetworkSession::Params::Params()
       quic_enable_connection_racing(false),
       quic_enable_non_blocking_io(false),
       quic_disable_disk_cache(false),
+      quic_prefer_aes(false),
       quic_max_number_of_lossy_connections(0),
       quic_packet_loss_threshold(1.0f),
       quic_socket_receive_buffer_size(kQuicSocketReceiveBufferSize),
@@ -147,6 +148,7 @@ HttpNetworkSession::HttpNetworkSession(const Params& params)
           params.quic_enable_connection_racing,
           params.quic_enable_non_blocking_io,
           params.quic_disable_disk_cache,
+          params.quic_prefer_aes,
           params.quic_max_number_of_lossy_connections,
           params.quic_packet_loss_threshold,
           params.quic_socket_receive_buffer_size,

net/http/http_network_session.h

@@ -115,6 +115,7 @@ class NET_EXPORT HttpNetworkSession
     bool quic_enable_connection_racing;
     bool quic_enable_non_blocking_io;
     bool quic_disable_disk_cache;
+    bool quic_prefer_aes;
     int quic_max_number_of_lossy_connections;
     float quic_packet_loss_threshold;
     int quic_socket_receive_buffer_size;

net/quic/quic_stream_factory.cc

@@ -553,6 +553,7 @@ QuicStreamFactory::QuicStreamFactory(
     bool enable_connection_racing,
     bool enable_non_blocking_io,
     bool disable_disk_cache,
+    bool prefer_aes,
     int max_number_of_lossy_connections,
     float packet_loss_threshold,
     int socket_receive_buffer_size,
@@ -578,6 +579,7 @@ QuicStreamFactory::QuicStreamFactory(
       enable_connection_racing_(enable_connection_racing),
       enable_non_blocking_io_(enable_non_blocking_io),
       disable_disk_cache_(disable_disk_cache),
+      prefer_aes_(prefer_aes),
       max_number_of_lossy_connections_(max_number_of_lossy_connections),
       packet_loss_threshold_(packet_loss_threshold),
       socket_receive_buffer_size_(socket_receive_buffer_size),
@@ -602,7 +604,7 @@ QuicStreamFactory::QuicStreamFactory(
   bool has_aes_hardware_support = cpu.has_aesni() && cpu.has_avx();
   UMA_HISTOGRAM_BOOLEAN("Net.QuicSession.PreferAesGcm",
                         has_aes_hardware_support);
-  if (has_aes_hardware_support)
+  if (has_aes_hardware_support || prefer_aes_)
     crypto_config_.PreferAesGcm();
   if (!IsEcdsaSupported())
     crypto_config_.DisableEcdsa();

net/quic/quic_stream_factory.h

@@ -115,6 +115,7 @@ class NET_EXPORT_PRIVATE QuicStreamFactory
       bool enable_connection_racing,
       bool enable_non_blocking_io,
       bool disable_disk_cache,
+      bool prefer_aes,
       int max_number_of_lossy_connections,
       float packet_loss_threshold,
       int socket_receive_buffer_size,
@@ -345,6 +346,9 @@ class NET_EXPORT_PRIVATE QuicStreamFactory
   // Set if we do not want to load server config from the disk cache.
   bool disable_disk_cache_;
 
+  // Set if AES-GCM should be preferred, even if there is no hardware support.
+  bool prefer_aes_;
+
   // Set if we want to disable QUIC when there is high packet loss rate.
   // Specifies the maximum number of connections with high packet loss in a row
   // after which QUIC will be disabled.

net/quic/quic_stream_factory_test.cc

@@ -218,6 +218,7 @@ class QuicStreamFactoryTest : public ::testing::TestWithParam<TestParams> {
                  /*enable_connection_racing=*/false,
                  /*enable_non_blocking_io=*/true,
                  /*disable_disk_cache=*/false,
+                 /*prefer_aes=*/false,
                  /*max_number_of_lossy_connections=*/0,
                  /*packet_loss_threshold=*/1.0f,
                  /*receive_buffer_size=*/0,