I2CP: Prevent sending data message before handshake with router is complete

core/java/src/net/i2p/client/I2PSessionImpl.java

@@ -619,6 +619,8 @@ public abstract class I2PSessionImpl implements I2PSession, I2CPMessageReader.I2
                 throw new I2PSessionException("Already closed");
             if (_state == State.INIT)
                 throw new I2PSessionException("Not open, must call connect() first");
+            if (_state == State.OPENING) // not before GOTDATE
+                throw new I2PSessionException("Session not open yet");
         }
         _producer.reportAbuse(this, msgId, severity);
     }

core/java/src/net/i2p/client/I2PSessionImpl2.java

@@ -252,6 +252,8 @@ class I2PSessionImpl2 extends I2PSessionImpl {
                 throw new I2PSessionException("Already closed");
             if (_state == State.INIT)
                 throw new I2PSessionException("Not open, must call connect() first");
+            if (_state == State.OPENING || _state == State.GOTDATE) // not before GOTDATE or session
+                throw new I2PSessionException("Session not open yet");
         }
         updateActivity();
 

core/java/src/net/i2p/client/I2PSessionMuxedImpl.java

@@ -261,6 +261,8 @@ class I2PSessionMuxedImpl extends I2PSessionImpl2 {
                 throw new I2PSessionException("Already closed");
             if (_state == State.INIT)
                 throw new I2PSessionException("Not open, must call connect() first");
+            if (_state == State.OPENING || _state == State.GOTDATE) // not before GOTDATE or session
+                throw new I2PSessionException("Session not open yet");
         }
         updateActivity();