Re: loopback interface and byte order

[Robert Lowe <Robert.H.Lowe () lawrence edu>]

Guy Harris wrote:

> > This leads me to another question.  I've seen recommendations to roll 
> > your
> > own structs for IP/TCP headers, hinting that there might be slight 
> > differences
> > in the definitions between platforms.  Is this really true?
>
>
> Yes.  For example, if I remember correctly, not all platforms' "struct 
> ip" represent the "header length and version" field in the same way - 
> some have bitfields and some have a single field for the header length 
> and version and macros to extract the header length and version from it.
>
> That's why tcpdump has its own headers.

Thanks again for all the terrific information.  I looked over the headers
included with tcpdump.  I think I'll use somewhat modified versions of
those.  In particular, I didn't traceback how u_int8_t gets defined,
which seems to appear naturally on some systems, but not on others.  I
think instead I'll rely on an autoconf macro, ac_create_stdint_h, to make
a header file for me and use uint8_t, for example, instead.  Reasonable?
Is there a better approach?

-Robert

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