1. DNS/実装/python/dnslib/README

について、ここに記述してください。

Python 3 support was added in Version 0.9.0 which represented a fairly major update to the library - the key changes include:

• Python 2.7/3.2+ support (the last version supporting Python 2.6
  • or earlier was version 0.8.3)
• The 'Bimap' interface was changed significantly to explicitly

  • split forward (value->text) lookups via getitem and reverse (text->value) lookups via getattr. Applications using the old interface will need to be updated.

• Hostnames are now returned with a trailing dot by default (in
  • line with RFC)
• Most object attributes are now typed in line with the record
  • definitions to make it harder to generate invalid packets
• Support for encoding/decoding resource records in 'Zone' (BIND)
  • file format
• Support for encoding/decoding packets in 'DiG' format
• Server framework allowing (in most cases) custom resolvers to
  • be created by just subclassing the DNSResolver class and overriding the 'resolve' method
• A lot of fixes to error detection/handling which should make
  • the library much more robust to invalid/unsupported data. The library should now either return a valid DNSRecord instance when parsing a packet or raise DNSError (tested via fuzzing)
• Improved utilities (dnslib.client, dnslib.proxy, dnslib.intercept)
• Improvements to encoding/decoding tests including the ability
  • to generate test data automatically in test_decode.py (comparing outputs against DiG)
• Ability to compare and diff DNSRecords

1.1. Classes

The key DNS packet handling classes are in dnslib.dns and map to the standard DNS packet sections:

• DNSRecord - container for DNS packet. Contains:
  • - DNSHeader - Question section containing zero or more DNSQuestion objects - Answer section containing zero or more RR objects - Authority section containing zero or more RR objects - Additional section containing zero or more RR objects
• DNS RRs (resource records) contain an RR header and an RD object)
• Specific RD types are implemented as subclasses of RD
• DNS labels are represented by a DNSLabel class - in most cases
  • this handles conversion to/from textual representation however does support arbitatry labels via a tuple of bytes objects

1.2. Usage

The default text representation of the DNSRecord is in zone file format: