Re: [lisp-snmp] Patch to asn.1 to change from parsergen to a modified cl-yacc

[Chun T. (binghe) <bin...@gm...>]

On 2009-2-9, at 14:44, John Fremlin wrote:

> Dear Chun Tian,
>
> "Chun Tian (binghe)" <bin...@gm...> writes:
> [...]
>>> To support the cool (oid ..) syntax you can easily add "asn.1/" to  
>>> the
>>> start of the string processed by OID method.
>>
>> It's not so easy when you've found following syntax is also well
>> supported:
>>
>> ASN.1 10 > (oid "SNMPv2-SMI::mib-2.SNMPv2-MIB::system")
>> #<OBJECT-ID SNMPv2-MIB::system (1) [9]>
>
> This syntax can easily be supported as follows
>
> (defmethod oid-parse ((source string))
>  (or
>   (with-input-from-string (s source)
>     (oid-parse s))
>   (with-input-from-string (s (concatenate 'string *asn.1-package- 
> prefix* source))
>     (oid-parse s))))

I'm afraid this function cannot work for (oid "SNMPv2- 
SMI::mib-2.SNMPv2-MIB::system") correctly, you just change it into:

(oid "ASN.1/SNMPv2-SMI::mib-2.SNMPv2-MIB::system")

How can you solve the second package name "SNMPv2-MIB" in that string?

>
>
> However, *asn.1-package-prefix* cannot contain a "." because of your
> strange readtable. So it must be changed to something other than
> "ASN.1/", perhaps "ASN1/"

The strange *oid-readtable* is my way to avoid the use of SPLIT- 
SEQUENCE, it just let #\. be treat as a separator. However, this  
method can cause unnecessary synbol intern in ASN.1 package, not the  
best way to read a OID string.

Give me more time to think out a better solution please.

>
>> Well, contact me if you really found your customers use such a MIB
>> module name, I think we can talk about this issue later:)
>
> It's kind of strange that you talk about making your package perfect  
> but
> have it so arranged that by loading in an MIB file one can overwrite
> your package itself . . .
>
> I guess it's not just C programmers who don't care about security ;-)

The *asn.1-package-prefix* was learnt from Common Lisp's CORBA  
language mapping. I think you've persuaded me, but I cannot change it  
until I can solve the OID reader syntax issue above.

--
Chun Tian (binghe)
NetEase.com, Inc.
P. R. China