The purpose is to block packet on OpenWRT. I plan to have ids run on raspberry pi and then send output as alert log to OpenWRT to drop packet based on the alert of IDS. Are there any tools/package recommended or is it possible to do this way?
IDS ----- (send log)---> Firewall on OpenWRT ---> Drop packet
I don't think it's possible to only block this specific packet...
For this, you have to run your IDS in inline mode...
With inline mode, your IDS can simply drop this single packet without a firewall.
Blocking the ip/port combination for some time is a more realistic use case for your desired setup.