This PR adds an unstable net::server module that enables the creation of UDP
and TCP DNS servers using base transport server, middleware and service building blocks.
This PR adds experimental support for client transport of DNS messages.
It also adds a new concept of unstable features which gate code that can introduce breaking changes also in non-breaking releases.
This PR fixes scanning (i.e., reading from presentation format) of domain
names that are just the root label. It also fixes how they are displayed:
previously they were empty, now they are displayed as a dot. It also adds a
new method Dname::fmt_with_dot that returns a placeholder type that displays
the name with a dot at the end.
This commit completely redesigns zone file parsing. The primary change is to
convert the scanner into a trait in order to allow multiple zone parser
implementations for different sources and purposes. A number of changes had
to be made in order to make this possible.
The commit also contains an initial implementation of a scanner that modifies
data in-place and can thus returned parsed data with only a minimal amount
of additional allocations. While working, this scanner is more a
proof-of-concept at this point to ensure that the API design is sound.
This commit is based on ideas and code proposed by @not-my-profile in #106.
This commit increases the minimal supported Rust version to 1.59.0.
