Fails with IPv6 DNS server

[bramp]

My default DNS server is a IPv6 address, and when the tool receives a DNS request it fails with a error

$ ./dns-mitm.py
DNS MitM by Adrian Vollmer, SySS GmbH
Warning: Failed to drop privileges
Warning: No hosts specified. Operating in passive mode.
127.0.0.1:60629 is requesting the A record of google.com
Forwarding DNS request to 2601:646:ca00:43c::1
Traceback (most recent call last):
  File "./dns-mitm.py", line 167, in <module>
    main()
  File "./dns-mitm.py", line 161, in main
    main_loop(udps)
  File "./dns-mitm.py", line 129, in main_loop
    answer = forwarded_dns_request(data)
  File "./dns-mitm.py", line 104, in forwarded_dns_request
    udps.sendto(data, (DNS_IP, 53))
socket.gaierror: [Errno 8] nodename nor servname provided, or not known

The fix is simple change line 103 from

udps = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

to

udps = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)

However, I suspect you'd want to check if DNS_IP is v4 or v6 and select AF_INET[6] appropriately.