#!/usr/bin/env python3

# Dictionary of items we need to track to perform txid filtering
"""

if c 

"""
requests = {}
SADDR=0
SPORT=1
DADDR=2
DPORT=3
TXID=4

def drop_packet():
    """ """
    return 0

def send(skb):
    """ Emulate sending of a DNS request"""
    request[(skb[SADDR], skb[SPORT], skb[DADDR], skb[DPORT])] = [skb[TXID], 0]


def receive(skb):
    """ Emulate receiving of a DNS response"""
    if skb[TXID] != request[(skb[DADDR], skb[DPORT], skb[SADDR], skb[SPORT])][0]:
        request[(skb[DADDR], skb[DPORT], skb[SADDR], skb[SPORT])][1] += 1
    if request[(skb[DADDR], skb[DPORT], skb[SADDR], skb[SPORT])][1] > threshold:
        drop_packet()

def main():
    """

    """
if __name__ == '__main__':
    main()