[En-Nut-Discussion] changes inside the ip stack?

[Gerd Mueller]

Hi Dave,

thank you. I will give it a try

Best regards,

Gerd

On Sat, 2005-05-28 at 01:21 -0400, Dave wrote:
> Hi Gerd,
> 
> While not directly related to the problem you asked about, I do have a
> fix for your workaround I thought you might like :-) While erasing the
> first 27 characters (9 telnet options) will work with your telnet
> client, it may break other clients. I know, because another telnet
> client I tested only sent 5 options, or 15 characters. I probably spent
> an entire day researching telnet, in detail, for my project. The RFCs
> that cover all the parts of telnet are scattered around, and it is a
> real mess.
> 
> Anyways, here is what you could do to 'fix' your workaround.
> 
> Delete the workaround
>     
> >     //27Byte workaround :-(
> >     fgets(nbuff,28,stream);
> 
> and find the 2nd fgets just a few lines down
> 
> > if (fgets(nbuff, sizeof(nbuff), stream) == 0)
> >             break;
> 
> and insert the following code somewhere after it.
> 
>         cp=nbuff;
>         while(*(cp)!=0)
>                 if(*cp==0xff)
>                         memcpy(cp,cp+(*(cp+1)==0xff?2:3),strlen(cp+1));
>                 else
>                         cp++;
> 
> Using memcpy the way I do may be abuse of the system, since the docs say
> not to use it of the source and destination buffers overlap, but it
> works for me. Use memmove instead if it is a concern.
> 
> What my code snippet does, is search the buffer for 0xFF, and if the
> next byte is also 0xFF it deletes 2 bytes, otherwise it deletes 3 bytes.
> If you would like code that sends back a suitable response to the telnet
> options received, let me know, and I'll share that code with you too,
> but just ignoring the options seem to work just as well.
> 
> I've expanded the portdio program into quite a bit more than it was,
> just like you did. I plan on sharing what I'm doing when I'm done. Your
> code already has a few odds and ends I have on my list of things to do.
> If you would like to share code and ideas with me on the subject, let me
> know. I written a few commands for mine that you don't have yet, that
> I'd be more than happy to share with you (or anyone else who asks).
> 
> -Dave
> 
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-- 
Gerd Müller                   NETWAYS GmbH
Senior Systems Engineer       Deutschherrnstr. 47a
Fon.0911/92885-0              D-90429 Nürnberg
Fax.0911/92885-33
gmueller at netways.de           http://www.netways.de