ASN.1 compiler error token "SYNTAX" unexpected

Question

I'm currently trying to compile a snippet of ASN.1 code. It looks as follows:

RFC1213-MIB DEFINITIONS ::= BEGIN
    IMPORTS 
        experimental FROM RFC1155-SMI
        OBJECT-TYPE FROM RFC-1212;

    mypersonaltest OBJECT IDENTIFIER ::= { experimental 1 }

    tester      OBJECT-TYPE 
        SYNTAX      INTEGER
        ACCESS      read-write
        STATUS      optional
        DESCRIPTION "This is a test"
        ::= { mypersonaltest 1 }

END

Now I'm always getting an error on the line SYNTAX INTEGER:

ASN.1 grammar parse error near line 9 (token "SYNTAX"): syntax error, unexpected TOK_SYNTAX, expecting TOK_PPEQ

Actually, this should work according my example I got here. What am I doing wrong?

score 1 · Accepted Answer · answered Aug 15 '13 at 20:32

1

This looks like an old version of that specification that uses ASN.1 MACRO notation instead of ASN.1 Information Object Classes. The MACRO notation was removed from ASN.1 in 1994. Please consider finding a newer version of your specification that used Information Object Classes instead of the obsolete MACRO notation.

It is possible that the tool you are using does not support ASN.1 MACRO notation (which was removed from ASN.1 in 1994). You could try using the free online compiler at http://asn1-playground.oss.com/ which I believe still supports MACRO notation. Note that the definition of OBJECT-TYPE must be seen by the compiler before "tester" (which uses the OBJECT-TYPE macro) is parsed.

I will repeat, that you will save yourself many headaches if you use a version of your ASN.1 specification that uses Information Object Classes rather than the obsolete ASN.1 MACRO notation.

answered Aug 15 '13 at 20:32

Paul Thorpe

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The above is an SNMP MIB module, which are written in the SMI language. SMI is based on ASN.1, but is not really ASN.1. More like "ASN.1" (air quotes). The above is probably good advice for true ASN.1, but not for SMI. In particular, it won't save you any headaches in writing MIB modules to try to use features of later versions of ASN.1 that are not allowed/permitted in MIB modules--such as Information Object Classes. It is actually likely the poster's error was produced by an actual ASN.1 compiler, where the poster should use a compiler that understands SMI instead. – Michael Kirkham Aug 20 '13 at 09:43
I have seen a version of the ASN.1 for RFC 1213 that was updated to use 1994 or later ASN.1 with information object classes rather than MACROs. I don't know the status of that specification, if it was an official attempt to modernize SNMP, but I do understand what you are saying about SMI not being ASN.1. This has led to much confusion with people trying to use ASN.1 Tools to handle MIBs when they need a MIB compiler instead of an ASN.1 compiler. – Paul Thorpe Aug 22 '13 at 20:04

score 1 · Answer 2 · answered Aug 16 '13 at 03:12

1

It should be OBJECT-TYPE, not OBJECT TYPE. There is something wrong with the MIB document, and you should try to find a proper version of it.

answered Aug 16 '13 at 03:12

Lex Li

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Ah! Sorry, I've copied that the wrong way. I already got `OBJECT-TYPE` everywhere where it gets mentioned. Edited the question. – Florian Müller Aug 16 '13 at 06:23

ASN.1 compiler error token "SYNTAX" unexpected

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