boilerplate code for ruby packet sniffer

sniff.rb

#!/usr/bin/env ruby
require 'packetfu'

# filter = argv[0] - tcpdump style.
# e.g. 'dst host bla.dom.tld and port http and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)'
# to cap. http traffic. or 'host W.X.Y.Z' to cap a speficic host/ip

cap = PacketFu::Capture.new(:start => true)

cap.save(:filter => ARGV[0])
cap.stream.each do |packet, index|
        pkt = PacketFu::Packet.parse packet
	puts "\n>> DISSECTION:\n"
	puts pkt.dissect
	puts "\n>> PAYLOAD:\n"
	puts pkt.payload
	puts "\n>> SIZE:\n"
	puts pkt.size
	
end

cool