How to drop a packet?

[TheTechRobo]

There are some packets I want to drop entirely through a module. How would I accomplish this?

[ickerwx]

Hi, thanks for trying out my little tool. Dropping packets (as in, TCP packets) ist not possible. It's a TCP proxy and therefore works on streams of data. The proxy does not see packets, you are reading data through file descriptors.

Dropping packets while mitm-ing a connection is quite involved, you would need to keep track of sequence numbers and modify every subsequent packet. This is beyond the scope of this tool.

[TheTechRobo]

Oh! I should have been more clear. My module (admittedly it will be quite complicated) is going to operate on the stream and parse it into bits of data. I want to "withhold" some of it. I'm not talking about the lower-level packets.

If I just return the data from the execute method without that data included, would that work? Can you return an empty bytes object?

[ickerwx]

You can absolutely return b'', but I didn't know what would happen with the socket, I never actually tried this. So I ran a quick little test. It looks like socket.send(b'') will not send anything, at least there was no traffic when I was sniffing with tcpdump.

[TheTechRobo]

Thanks, that's very helpful!

[ickerwx]

Moved this to a discussion thread, in case I misunderstood what you want to do.