Tcl - Building packets in Tcl

Author

Building packets in Tcl

Christopher Nelson

2006-08-22, 7:02 pm

I'm doing some funky network stuff with Tcl and I've started writing
horrible procs like:

# src and dst are MAC addresses, represented as 6-element lists
# data is the string to send.
proc buildFrame { dst src data {type NA} } {
if {"$type" == "NA"} {
set tl [string length $data]
} else {
set tl $type
}
set frame [binary format c6c6Sa* $dst $src $tl $data]
return $frame
}

(Horrible because I'm sure someone else has done this and I hate
reinventing the wheel.)

I wonder if there isn't a better way. I use libnet, a little, and was
looking for a Tcl binding. I didn't find it. Maybe SWIG would help
but I Googled "libnet tcl" and found
http://marc2.theaimsgroup.com/?l=li...17350204370&w=2 which
says:

scripting language extensions:

Perl Net::RawIP module - http://quake.skif.net/RawIP/
Sun packet shell (for tcl) - http://playground.sun.com/psh/

But the psh link leads to an empty directory. Does anyone know if psh
moved? Any other suggestions?

George Peter Staplin

2006-08-22, 10:01 pm

Christopher Nelson wrote:
> I'm doing some funky network stuff with Tcl and I've started writing
> horrible procs like:
>
> # src and dst are MAC addresses, represented as 6-element lists
> # data is the string to send.
> proc buildFrame { dst src data {type NA} } {
> if {"$type" == "NA"} {
> set tl [string length $data]
> } else {
> set tl $type
> }
> set frame [binary format c6c6Sa* $dst $src $tl $data]
> return $frame
> }
>
> (Horrible because I'm sure someone else has done this and I hate
> reinventing the wheel.)
>
> I wonder if there isn't a better way. I use libnet, a little, and was
> looking for a Tcl binding.

You might find this interesting:
http://www.hping.org/

The author of Hping is somewhat well known in the Tcl community.

-George

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