Generating a virtual ECU with standardized subservice identifiers

[rumpelsepp]

@LeventCelik asked in #453 (comment)

Could you also help me with generating a virtual ECU with standardized subservice identifiers? For instance, using 0x10, SBF of 0x1 for default session, 0x3 for extended, etc. Can I do that, and if I can, which command shall I use?

Secondly, are the services with 'null' (such as
"0x01 (ShowCurrentData)": null,
"0x02 (ShowFreezeFrameData)": null,
"0x03 (ShowstoredDiagnosticTroubleCodes)": null,
) not available?

I am trying to understand the tool, but could not find these in the documentation.

/cc @fkglr

[fkglr]

Could you also help me with generating a virtual ECU with standardized subservice identifiers? For instance, using 0x10, SBF of 0x1 for default session, 0x3 for extended, etc. Can I do that, and if I can, which command shall I use?

You can control some of the randomness of the ECU using its command line parameters. E.g. you can create a virtual ECU which has at least the three session 0x01, 0x02 and 0x03 using the parameter --mandatory_sessions [1,2,3]. You can also suppress creating further sessions by setting the probability of session activation to zero with --p_session 0.
These sessions however don't have a specific behavior. You would have to program that in on your own.
What you can do is to also specify available services for all sessions explicitly like so --mandatory_services "[ReadDataByIdentifier, DiagnosticSessionControl, TesterPresent, EcuReset, ClearDiagnosticInformation]", or set the probability to one in order to activate all UDS services on each session --p_service 1.
For some of these services, there already is a meaningful implementation, however for some of them, there currently is not, so by default a GeneralReject UDS error will be returned.
Just in case you are intereseted, you could add support for further services in server.py for the class RandomUDSServer.

Secondly, are the services with 'null' (such as
"0x01 (ShowCurrentData)": null,
"0x02 (ShowFreezeFrameData)": null,
"0x03 (ShowstoredDiagnosticTroubleCodes)": null,
) not available?

The lists behind the services refer to the available sub-functions of that service. Services which by specification do not have subfunctions have null listed instead.
Here you can also see which sessions are reachable out of a certain session. E.g. if for session 0x01 the map contains "0x10 (DiagnosticSessionControl)": "['0x01', '0x02']", then you can switch to session 0x01 and 0x02 from this session 0x01 using the service DiagnosticSessionControl (0x10).

I hope this helps

[LeventCelik]

Thanks, that adds a lot of clarity! The current state of the documentation seem to go over these a bit fast, but now I understand.

Is there any public information about which services are fully implemented, or should I get that by probing over the available services and eliminating the ones that return general reject?
Are all the implemented services located at https://github.com/Fraunhofer-AISEC/gallia/blob/603cef0c263cf91af98e5e8318d1d8265767d300/src/gallia/services/uds/core/service.py ?

[rumpelsepp]

These services are relevant for the client. @fkglr correct me if I am wrong; the implemented services for the server are here: https://github.com/Fraunhofer-AISEC/gallia/blob/603cef0c263cf91af98e5e8318d1d8265767d300/src/gallia/services/uds/server.py

[fkglr]

That is correct. More precisely starting from

gallia/src/gallia/services/uds/server.py

Line 550 in 603cef0

def ecu_reset(self, request: service.ECUResetRequest) -> service.UDSResponse:

.