0007207: CamInd's "lower-layer" fields should not be optional

ETSI's Bug Tracker - CAM

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Project

Category

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Date Submitted

Last Update

0007207

CAM

ATS

public

27-10-2015 08:33

23-11-2016 14:17

Reporter

Alexandre Berge

Assigned To

Sebastian Muellers

Priority

normal

Severity

minor

Reproducibility

have not tried

Status

resolved

Resolution

fixed

Platform

OS Version

Product Version

Test_Spec_TS102868_v1.3.1

Target Version

Next Release

Fixed in Version

Summary

0007207: CamInd's "lower-layer" fields should not be optional

Description

From Elemer Lelik (Ericsson):

type record CamInd {
    CAM msgIn,
    UInt8 gnNextHeader optional,
    UInt8 gnHeaderType optional,
    UInt8 gnHeaderSubtype optional,
    UInt32 gnLifetime optional,
    UInt8 gnTrafficClass optional,
    UInt16 btpDestinationPort optional,
    UInt16 btpInfo optional
}
with {
    encode (msgIn) "LibItsCam_asn1"
}

The msgIn part is a PER encoded octetstring, the rest of the fields are encoded in binary according to their declarations.

Problem is , due to the fact that the fields are optional, decoding becomes impossible: let’s assume that we have successfully decode the PER part , which is followed by a single octetsay ‘AB’O;
This can be decoded as :
gnNextHeader ‘AB’O,
all the rest of the filed s being omitted,
or the first field omitted, and the next set to ‘AB’
or a number of other combinations.

Steps To Reproduce

Additional Information

Those fields are appended by the Test Adapter (CamPort in this case) to provide information about lower layer (mainly in order to know GN's packet type and BTP destination port). In our implementation of the Codec, they are obviously considered as non optional.
The TTCN-3 declaration is faulty here, those fields should not be optional:

type record CamInd {
    CAM msgIn,
    UInt8 gnNextHeader,
    UInt8 gnHeaderType,
    UInt8 gnHeaderSubtype,
    UInt32 gnLifetime,
    UInt8 gnTrafficClass,
    UInt16 btpDestinationPort,
    UInt16 btpInfo
}
with {
    encode (msgIn) "LibItsCam_asn1"
}