Provide stop for sniff even when no packets received

[robgom]

Hi there,
this is a request to reopen #989 - I haven't received any feedback to my recent question.
Missing the functionality affects our code.

Quoting myself:

Can it be reopened?
We observe the problem on Windows.
With scapy 2.3.1 we distributed local version of scapy, which used the following pattern:

p = None
while stop_filter and stop_filter(p):
... the loop as normal

On Windows it works, because there's PcapTimeout exception raised in case of no packets, which allows the condition to be checked.
It breaks backward compatibility, because it requires stop_filter to be aware of possible "None" as packet.

What about the mentioned stop_sniff additional parameter to sniff as alternative? On Windows it would work, as indicated before, even if stop wouldn't occur immediately. I don't know about other platforms, though.

What's your opinion?

Regards,
Robert

[gpotter2]

Hi & sorry for the delay.

Would a thing such as #1523 fit your needs ?

[robgom]

Thank you for the heads up!

I think that sniff interface turned into a beast - way too many arguments.

However, I think that it'd fit for our use case - I haven't had a chance to play with it.

Regards,
Robert

[llamasoft]

This is going to sound pretty dumb, but when I ran into a similar issue, I worked around it by exploiting the fact that scapy can sniff its own packets. Just send a dummy packet that matches the filter you set up and it'll cause sniff to "wake up" and realize it needs to stop. This is akin to pushing a None into a Queue to indicate that no more work is coming.

Just my $0.02.

[gpotter2]

See #1999