[fpc-pascal] Thoughts on Shell Approach to TCP Sockets

Mark Morgan Lloyd markMLl.fpc-pascal at telemetry.co.uk
Fri Mar 20 12:35:33 CET 2015

Michael Schnell wrote:
> On 03/20/2015 12:18 AM, Coyo Stormcaller wrote:
>> With a Userspace TCP/IP stack, I can send strange traffic with a raw 
>> UDP port.
> In fact colleagues of mine once in Delphi implemented a TCP - like 
> solution that uses UDP transfer to do secure, especially low overhead 
> transfers via GPRS.
> So I understand that such User-space IP stack extensions might make 
> sense in certain cases.
> But a User-Space "TCP/IP-Stack" implementation that sits on naked 
> Ethernet does not seem to make any practical sense.

It does if the objective is to experiment with variant protocols. Also 
remember that things like nmap already reimplement some parts of IP, so 
there's strong precedent.

I don't know what language implementation would be best for the job. The 
problem is that it's convenient to be able to overlay e.g. an IP packet 
with a predefined type e.g. a record describing the header followed by 
an array encompassing the data, however the actual length of the data is 
unknown at compilation time which means that hardware-supported bounds 
checking is less than useful.

Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]

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