Robert Krten

How do I adjust the rate at which I receive TCP/IP data?

I want spamd to stutter not just on the transmission of data, but
I want it to present a "slow" stream on incoming data as well,
under program control.

The scenario is that the spammer has identified themselves for
special treatment, and when they send the SMTP "DATA" command
I want them to suddenly behave as if I'm only connect to the
internet via a 300 baud modem instead of ADSL.

Is such a thing possible? I just need a push in the right
direction; is setsockopt(2) the way to do this, or is there
a different / better way?

I don't want to slow *all* incoming streams, just select ones,
and only after some amount of data has passed through at a
high rate.

Thanks in advance for your help!

Cheers,
-RK
--
Robert Krten, Antique computer collector looking for PDP-8 and PDP-8/S
minicomputers; check out their "good home" at www.parse.com/~museum

Peter N. M. Hansteen

info2007@parse.com (Robert Krten) writes:

> The scenario is that the spammer has identified themselves for
> special treatment, and when they send the SMTP "DATA" command
> I want them to suddenly behave as if I'm only connect to the
> internet via a 300 baud modem instead of ADSL.

for that specific scenario, adjusting spamd's -s option to something
higher than the default 1 second is the easy way. with really naive
spambots, if you increase the -s value to 10, they'll hang around ten
times longer (like 4352 seconds instead of just the regular 435)

- P
--
Peter N. M. Hansteen, member of the first RFC 1149 implementation team
http://bsdly.blogspot.com/ http://www.datadok.no/ http://www.nuug.no/
"Remember to set the evil bit on all malicious network traffic"
delilah spamd[29949]: 85.152.224.147: disconnected after 42673 seconds.

Robert Krten

Peter N. M. Hansteen <peter@bsdly.net> wrote:
> info2007@parse.com (Robert Krten) writes:

> > The scenario is that the spammer has identified themselves for
> > special treatment, and when they send the SMTP "DATA" command
> > I want them to suddenly behave as if I'm only connect to the
> > internet via a 300 baud modem instead of ADSL.

> for that specific scenario, adjusting spamd's -s option to something
> higher than the default 1 second is the easy way. with really naive
> spambots, if you increase the -s value to 10, they'll hang around ten
> times longer (like 4352 seconds instead of just the regular 435)

As I understand it, that (-s) is the *outgoing* stutter -- once they
say "DATA" and spamd has said "ok, go ahead and send", the spammer will
send their entire spam message at ADSL speed; I want them to be choked
down to 300 baud so that each character of spam they send takes a long
time to arrive...

Am I being clearer now? :-)

Cheers,
-RK
--
Robert Krten, Antique computer collector looking for PDP-8 and PDP-8/S
minicomputers; check out their "good home" at www.parse.com/~museum

Daniel Hartmeier

On Fri, 23 Nov 2007 12:10:20 +0000, Robert Krten wrote:

> As I understand it, that (-s) is the *outgoing* stutter -- once they
> say "DATA" and spamd has said "ok, go ahead and send", the spammer will
> send their entire spam message at ADSL speed; I want them to be choked
> down to 300 baud so that each character of spam they send takes a long
> time to arrive...

Look at spamd's -w option

-w window
Set the socket receive buffer to this many bytes, adjusting the
window size.

This is done using setsockopt(2) SO_RCVBUF. If your receive buffer is
only one character, the peer can only send a single character, then has
to wait until your program reads that. Your program can wait a couple
of seconds between reads, slowing the flow to X bytes per second.

Daniel

Robert Krten

Daniel Hartmeier <daniel@benzedrine.cx> wrote:
> On Fri, 23 Nov 2007 12:10:20 +0000, Robert Krten wrote:

> > As I understand it, that (-s) is the *outgoing* stutter -- once they
> > say "DATA" and spamd has said "ok, go ahead and send", the spammer will
> > send their entire spam message at ADSL speed; I want them to be choked
> > down to 300 baud so that each character of spam they send takes a long
> > time to arrive...

> Look at spamd's -w option

> -w window
> Set the socket receive buffer to this many bytes, adjusting the
> window size.

> This is done using setsockopt(2) SO_RCVBUF. If your receive buffer is
> only one character, the peer can only send a single character, then has
> to wait until your program reads that. Your program can wait a couple
> of seconds between reads, slowing the flow to X bytes per second.

Sweet, so that's what that does :-)

Thanks Daniel!

Cheers,
-RK
--
Robert Krten, Antique computer collector looking for PDP-8 and PDP-8/S
minicomputers; check out their "good home" at www.parse.com/~museum