Wireshark mailing list archives
Re: MMS decoding problem
From: Salman Malik <salmanmk () live com>
Date: Sun, 8 Jan 2012 19:14:01 +0000
Thanks Sam. I am providing all the referenced data to the compiler (otherwise it raises error). So here is the complete picture: I have a buffer containing following byte stream: A8 26 80 03 00 FD E8 81 01 0A 82 01 0A 83 01 05 A4 16 80 01 01 81 03 05 C4 E0 82 0C 03 19 00 44 E9 19 00 40 64 4D 00 A8 I know the structure type of the above buffer. The structure is a sequence whos ASN definition is given below: Initiate-RequestPDU ::= SEQUENCE --This is carried as a payload of a field having type ANY in the ACSE layer (the field definition is given below) { localDetailCalling [0] IMPLICIT Integer32 OPTIONAL, proposedMaxServOutstandingCalling [1] IMPLICIT Integer16, proposedMaxServOutstandingCalled [2] IMPLICIT Integer16, proposedDataStructureNestingLevel [3] IMPLICIT Integer8 OPTIONAL, mmsInitRequestDetail [4] IMPLICIT InitRequestDetail } EXTERNALt ::= [UNIVERSAL 8] IMPLICIT SEQUENCE { direct-reference OBJECT IDENTIFIER OPTIONAL, indirect-reference INTEGER OPTIONAL, data-value-descriptor ObjectDescriptor OPTIONAL, encoding CHOICE {single-ASN1-type [0] ANY, --This field carries the above structure in itself octet-aligned [1] IMPLICIT OCTET STRING, arbitrary [2] IMPLICIT BIT STRING} } The author of asn1c compiler says that the Initiate-RequestPDU should be declared as [8] IMPLICIT SEQUENCE (not just SEQUENCE) in order to be properly decoded, but since I am passing Initiate-RequestPDU to a different decoding function, I need to somehow tell the decoder of the nature of context-specific tag (which I am not sure how I should go about). Any ideas ?
Date: Sat, 7 Jan 2012 13:32:11 -0800 From: vieuxtech () gmail com To: wireshark-users () wireshark org Subject: Re: [Wireshark-users] MMS decoding problem On Fri, Jan 6, 2012 at 7:27 AM, Salman Malik <salmanmk () live com> wrote:I know this is not directly related to wireshark but I expect that most of you will be able to help me on this one. I am using asn1c Compiler to decode MMS protocol (transported over TPKT, COTP,Session, Presentation, ACSE layers). The problem that I am having is the asn1c compiler complains of unexpected tag when I decode the MMS layer packets. I suspect that this isWhich tag, in which message? Its sounds more like a context dependent tag (tags are just numbers defining data types, but there are standard ones, app dependent ones, and context dependent ones), nothing to do with context from the wrapping protocols. Is it possible you didn't find all the reference ASN and feed it to your asn compiler? Maybe you can find an ASN.1 verifier, that can tell you whether you provided all referenced ASN types and definitions? I've never used an ASN.1 compiler, we always hand encode and decoded messages for code space efficiency reasons. Cheers, Sam ___________________________________________________________________________ Sent via: Wireshark-users mailing list <wireshark-users () wireshark org> Archives: http://www.wireshark.org/lists/wireshark-users Unsubscribe: https://wireshark.org/mailman/options/wireshark-users mailto:wireshark-users-request () wireshark org?subject=unsubscribe
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Current thread:
- MMS decoding problem Salman Malik (Jan 06)
- Re: MMS decoding problem Sam Roberts (Jan 07)
- Re: MMS decoding problem Salman Malik (Jan 08)
- Re: MMS decoding problem Sam Roberts (Jan 07)