dnscommon.r2py cannot parse replies containing NS, PTR types of queries

[pranavnyu]

• dnscommon.r2py replies with KeyError when query is of type NS
  for e.g. present code returns this:

User traceback:
  "dylink.r2py", line 546, in <module>
  "dylink.r2py", line 407, in dylink_dispatch
  "dylink.r2py", line 520, in evaluate
  "librepy.r2py", line 153, in <module>
  "dylink.r2py", line 446, in _dylink_dispatch
  "dylink.r2py", line 407, in dylink_dispatch
  "dylink.r2py", line 520, in evaluate
  "ut_dnsquery_namingserver.r2py", line 11, in <module>
  "ut_dnsquery_namingserver.r2py", line 8, in test_namingServer
  "dnsquery.r2py", line 222, in namingServer
  "dnsquery.r2py", line 140, in dns_connection
  "dnscommon.r2py", line 406, in convert_packet_to_dictionary
  "dnscommon.r2py", line 459, in _read_answer_section
  "dnscommon.r2py", line 504, in _read_single_answer

Exception (with type 'exceptions.KeyError'): 49164

• Wrong output when query is of type PTR because of https://github.com/SeattleTestbed/seattlelib_v2/blob/master/dnscommon.r2py#L569 function and limit ot IPv4 addresses only,. Basically, dnscommon is not able to create dictionary from reply packet received from DNS.

Testing module: dnsquery
    Running: ut_dnsquery_reverselookup.r2py                     [ FAIL ]
--------------------------------------------------------------------------------
Standard out :
..............................Produced..............................
('173.252.120.6', {'address': '21.101.100.103'})

rather output should be domain name for the respective IP address

We need to create a patch for the same in https://github.com/SeattleTestbed/seattlelib_v2/blob/master/dnscommon.r2py#L464 in _read_single_answer function.
-> https://github.com/SeattleTestbed/seattlelib_v2/blob/master/dnscommon.r2py#L522 should be edited and code should be added for different types like already done for type 'SOA'.

[asm582]

I tried to test some of your implementations may be i am incorrect but i found that your namingServer implementation does not seem to be working for me. I think i added changes for the dnscommon.r2py that you suggested but it hangs when i use you dnsquery.r2py library to test it.