Fix issue with IPv6 and blocking

[vpetersson]

When blocking an IPv6 IP, we get the following error:

pi@wott0:~ $ sudo wott-agent
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/iptc/ip4tc.py", line 1093, in set_dst
    daddr = _a_to_i(socket.inet_pton(socket.AF_INET, addr))
OSError: illegal IP address string passed to inet_pton

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/wott-agent", line 11, in <module>
    load_entry_point('wott-agent==0.1.5', 'console_scripts', 'wott-agent')()
  File "/usr/lib/python3/dist-packages/agent/__main__.py", line 43, in main
    run(ping=True, debug=args.debug, dev=args.dev)
  File "/usr/lib/python3/dist-packages/agent/__init__.py", line 423, in run
    send_ping(debug=debug, dev=dev)
  File "/usr/lib/python3/dist-packages/agent/__init__.py", line 276, in send_ping
    security_helper.block_ports(pong.get('block_ports', {'tcp': [], 'udp': []}))
  File "/usr/lib/python3/dist-packages/agent/security_helper.py", line 186, in block_ports
    update_iptables(TABLE, INPUT_CHAIN, rules)
  File "/usr/lib/python3/dist-packages/agent/security_helper.py", line 165, in update_iptables
    iptc_helper.add_rule(table, chain, r)
  File "/usr/lib/python3/dist-packages/agent/iptc_helper.py", line 84, in add_rule
    iptc_rule = encode_iptc_rule(rule_d, ipv6)
  File "/usr/lib/python3/dist-packages/agent/iptc_helper.py", line 339, in encode_iptc_rule
    _iptc_setrule(iptc_rule, name, rule_d[name])
  File "/usr/lib/python3/dist-packages/agent/iptc_helper.py", line 443, in _iptc_setrule
    _iptc_setattr(iptc_rule, name, value)
  File "/usr/lib/python3/dist-packages/agent/iptc_helper.py", line 434, in _iptc_setattr
    setattr(object, name, value)
  File "/usr/lib/python3/dist-packages/iptc/ip4tc.py", line 1095, in set_dst
    raise ValueError("invalid address %s" % (addr))
ValueError: invalid address ::1

Blocking IPv6 is unfortunately required for even blocking IPv4 traffic.

[a-martynovich]

iptc.easy.add_rule needs to know if an address is v6 or not in advance.

So, for every block_networks and block_ports element there needs to be an IP version.

[vpetersson]

We also need to add a column in the dashboard showing IPv4 or IPv6 (even if it is obvious to a trained eye).