1. 1 NSIS Interim Meeting 2005, Munich GIMPS Implementation Bernd Schloer, Christian Dickmann, Andreas Westermaier Xiaoming Fu, Hannes Tschofenig, Elwyn Davies May 2005

2. 2 NSIS Interim Meeting 2005, Munich Project overview General implementation approach Important key elements Message-to-FSM distributor Finite state machine NTLP-to-NSLP API TLS over TCP as transport Diagnostics tool (Ping tool) Outline

3. 3 NSIS Interim Meeting 2005, Munich Started in November 2004 Co-operation between Göttingen, Munich, and INT (France) Current developers: Core team: Bernd Schloer, Christian Dickmann (Göttingen), Andreas Westermaier (Munich) Contributors: Henning Peters, Ingo Juchem, Sebastian Willert, Nils Röttger (Göttingen), Alex Zrim, Tseno Tsenov (Munich), Julien Abeille, Youssef Abidi (France) Project overview

4. 4 NSIS Interim Meeting 2005, Munich Current status Basic funcitons of GIMPS-05: implemented including basic API currently IPv4 only Ping test tool: supported Ethereal tool for monitoring GIMPS messages: developed A running testbed Basic TLS support

5. 5 NSIS Interim Meeting 2005, Munich Design overview

6. 6 NSIS Interim Meeting 2005, Munich Message-to-FSM Distributor

7. 7 NSIS Interim Meeting 2005, Munich Check if associated NSLP application is supported by this Node – bypass if not Lookup the flow. Direction determines if senderFSM or receiverFSM is used Create flow and/or FSM if not existing already Validate message Trigger event of the FSM and pass the message Message-to-FSM Distributor

8. 8 NSIS Interim Meeting 2005, Munich Design overview

9. 9 NSIS Interim Meeting 2005, Munich draft-fu-nsis-ntlp-statemachine-02 serves as basis for our implementation Process message according to current running state Generate message in response Maybe pass message to higher layer Maintain message associations (MA) Setup message associations Manage reuse of message associations Maintain message routing state (MRS) Maintain timers Send and receive refreshing Messages State machine

10. 10 NSIS Interim Meeting 2005, Munich API

11. 11 NSIS Interim Meeting 2005, Munich Communication with NSLP layer Combination of unix sockets and shared memory Several NSLP application may connect simultaneously API calls may trigger FSM events FSM passes information and incoming message the NSLP application through the API API

12. 12 NSIS Interim Meeting 2005, Munich TLS Support Used the OpenSSL library TLS handshake triggered by corresponding Stack Proposal in GIMPS-Query Client authentication currently optional No certificate revokation checks NSLP application has currently no possibility to choose desired cipher suite or if it requires client authentication No support to inform the NSLP application about possible connection failures

13. 13 NSIS Interim Meeting 2005, Munich Lessons learned More accurate understanding of GIMPS specifications through work on implementation E.g., stack proposal, message state refresh How to implement it in software systems Implementing an efficient FSM We took a FSM framework used in the Linux kernel 2.6 Current Hashtable implementation is basic For real environment a more scalable solution might be necessary Ethereal dissector helps debugging message format

14. 14 NSIS Interim Meeting 2005, Munich Open issues Stack-Proposal in Response message Switching from TCP to TLS How to choose the peer identity? Higher layer information specification Route change cases GIMPS Hop count WaitConfirm state for Query  FSM/spec issue State repository for upstreaming and downstreaming in middle node

15. 15 NSIS Interim Meeting 2005, Munich Discussions Comments, suggestions welcome!