HTTP2 draft 13: support unknown frame types and settings types as extensions.

net/spdy/spdy_framer.cc

Index: net/spdy/spdy_framer.cc
diff --git a/net/spdy/spdy_framer.cc b/net/spdy/spdy_framer.cc
index d323e715a049216cbfed018f0e3a1533eea8399a..313ed8d2d373a2157bdebdf15644e1186d67c146 100644
--- a/net/spdy/spdy_framer.cc
+++ b/net/spdy/spdy_framer.cc
@@ -497,16 +497,16 @@ const char* SpdyFramer::FrameTypeToString(SpdyFrameType type) {
       return "WINDOW_UPDATE";
     case CREDENTIAL:
       return "CREDENTIAL";
-    case BLOCKED:
-      return "BLOCKED";
     case PUSH_PROMISE:
       return "PUSH_PROMISE";
     case CONTINUATION:
       return "CONTINUATION";
-    case ALTSVC:
-      return "ALTSVC";
     case PRIORITY:
       return "PRIORITY";
+    case ALTSVC:
+      return "ALTSVC";
+    case BLOCKED:
+      return "BLOCKED";
   }
   return "UNKNOWN_CONTROL_TYPE";
 }
@@ -837,7 +837,6 @@ void SpdyFramer::ProcessControlFrameHeader(uint16 control_frame_type_field) {
   // or add them to parsing + serialization methods for SPDY3.
   // Early detection of deprecated frames that we ignore.
   if (protocol_version() <= SPDY3) {
-
     if (control_frame_type_field == CREDENTIAL) {
       current_frame_type_ = CREDENTIAL;
       DCHECK_EQ(SPDY3, protocol_version());
@@ -849,10 +848,31 @@ void SpdyFramer::ProcessControlFrameHeader(uint16 control_frame_type_field) {
 
   if (!SpdyConstants::IsValidFrameType(protocol_version(),
                                        control_frame_type_field)) {
-    DLOG(WARNING) << "Invalid control frame type " << control_frame_type_field
-                  << " (protocol version: " << protocol_version() << ")";
-    set_error(SPDY_INVALID_CONTROL_FRAME);
-    return;
+    if (protocol_version() <= SPDY3) {
+      DLOG(WARNING) << "Invalid control frame type " << control_frame_type_field
+                    << " (protocol version: " << protocol_version() << ")";
+      set_error(SPDY_INVALID_CONTROL_FRAME);
+      return;
+    } else {
+      // In HTTP2 we ignore unknown frame types for extensibility, as long as
+      // the rest of the control frame header is valid.
+      // We rely on the visitor to check validity of current_frame_stream_id_.
+      bool valid_stream = visitor_->OnUnknownFrame(current_frame_stream_id_,
+                                                   control_frame_type_field);
+      if (valid_stream) {
+        DVLOG(1) << "Ignoring unknown frame type.";
+        CHANGE_STATE(SPDY_IGNORE_REMAINING_PAYLOAD);
+      } else {
+        // Report an invalid frame error and close the stream if the
+        // stream_id is not valid.
+        DLOG(WARNING) << "Unknown control frame type "
+                      << control_frame_type_field
+                      << " received on invalid stream "
+                      << current_frame_stream_id_;
+        set_error(SPDY_INVALID_CONTROL_FRAME);
+      }
+      return;
+    }
   }
 
   current_frame_type_ = SpdyConstants::ParseFrameType(protocol_version(),
@@ -970,7 +990,6 @@ void SpdyFramer::ProcessControlFrameHeader(uint16 control_frame_type_field) {
     case BLOCKED:
       if (current_frame_length_ != GetBlockedSize() ||
           protocol_version() <= SPDY3) {
-        // TODO(mlavan): BLOCKED frames are no longer part of SPDY4.
         set_error(SPDY_INVALID_CONTROL_FRAME);
       } else if (current_frame_flags_ != 0) {
         set_error(SPDY_INVALID_CONTROL_FRAME_FLAGS);
@@ -1732,7 +1751,12 @@ bool SpdyFramer::ProcessSetting(const char* data) {
   // Validate id.
   if (!SpdyConstants::IsValidSettingId(protocol_version(), id_field)) {
     DLOG(WARNING) << "Unknown SETTINGS ID: " << id_field;
-    return false;
+    if (protocol_version() <= SPDY3) {
+      return false;
+    } else {
+      // In HTTP2 we ignore unknown settings for extensibility.
+      return true;
+    }
   }
   id = SpdyConstants::ParseSettingId(protocol_version(), id_field);