= 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

== 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

== Usage ==

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