Add support for GCM cipher suites from RFC 7714.

talk/session/media/mediasession.h

Index: talk/session/media/mediasession.h
diff --git a/talk/session/media/mediasession.h b/talk/session/media/mediasession.h
index 8a7f4ccf06758db5453b84c43bfadc1f2dceddd6..3af4bd693b25333299ff070038f1e0eaeb1a0dfd 100644
--- a/talk/session/media/mediasession.h
+++ b/talk/session/media/mediasession.h
@@ -103,7 +103,8 @@ struct MediaSessionOptions {
       rtcp_mux_enabled(true),
       bundle_enabled(false),
       video_bandwidth(kAutoBandwidth),
-      data_bandwidth(kDataMaxBandwidth) {
+      data_bandwidth(kDataMaxBandwidth),
+      enable_gcm_crypto_suites(false) {
   }
 
   bool has_audio() const {
@@ -144,6 +145,7 @@ struct MediaSessionOptions {
   // bps. -1 == auto.
   int video_bandwidth;
   int data_bandwidth;
+  bool enable_gcm_crypto_suites;
   TransportOptions transport_options;
 
   struct Stream {
@@ -543,18 +545,26 @@ const VideoContentDescription* GetFirstVideoContentDescription(
 const DataContentDescription* GetFirstDataContentDescription(
     const SessionDescription* sdesc);
 
-void GetSupportedAudioCryptoSuites(std::vector<int>* crypto_suites);
-void GetSupportedVideoCryptoSuites(std::vector<int>* crypto_suites);
-void GetSupportedDataCryptoSuites(std::vector<int>* crypto_suites);
-void GetDefaultSrtpCryptoSuites(std::vector<int>* crypto_suites);
+void GetSupportedAudioCryptoSuites(std::vector<int>* crypto_suites,
+    const MediaSessionOptions& options);

[pthatcher1, 2015/12/21 22:30:27]

This looks a lot better, but two things:

1.  The out parameter should be last, and the options first.

2.  The MediaSessionOptions struct is huge.  Could you define a smaller struct
instead?  Perhaps something like CryptoOptions?  Then those could be passed
here.  In fact, it would be nice to pass that around and store that everywhere
you currently pass around store a bool.  So instead of 

SetEnableGcmCryptoSuites(bool enable_gcm_crypto_suites) {   
  enable_gcm_crypto_suites_ = enable_gcm_crypto_suites; 
}

And the like, we could have 

SetCryptoOptions(const CryptoOptions& crypto_options) { 
  crypto_options_ = crypto_options_; 
}.  

I think that would be cleaner and make it easier to add other controls over
crypto suites in the future.

[joachim, 2015/12/21 23:37:57]

Done
Ok, makes sense. Added struct in sslstreamadapter.h and changed various
methods/classes.

+void GetSupportedVideoCryptoSuites(std::vector<int>* crypto_suites,
+    const MediaSessionOptions& options);
+void GetSupportedDataCryptoSuites(std::vector<int>* crypto_suites,
+    const MediaSessionOptions& options);
+void GetDefaultSrtpCryptoSuites(std::vector<int>* crypto_suites,
+    const MediaSessionOptions& options);
 void GetSupportedAudioCryptoSuiteNames(
-    std::vector<std::string>* crypto_suite_names);
+    std::vector<std::string>* crypto_suite_names,
+    const MediaSessionOptions& options);
 void GetSupportedVideoCryptoSuiteNames(
-    std::vector<std::string>* crypto_suite_names);
+    std::vector<std::string>* crypto_suite_names,
+    const MediaSessionOptions& options);
 void GetSupportedDataCryptoSuiteNames(
-    std::vector<std::string>* crypto_suite_names);
+    std::vector<std::string>* crypto_suite_names,
+    const MediaSessionOptions& options);
 void GetDefaultSrtpCryptoSuiteNames(
-    std::vector<std::string>* crypto_suite_names);
+    std::vector<std::string>* crypto_suite_names,
+    const MediaSessionOptions& options);
 
 }  // namespace cricket