# NAME DNS::Unbound - libunbound in Perl # SYNOPSIS my $dns = DNS::Unbound->new()->set_option( verbosity => 2 ); # This appears to be safe: $dns->enable_threads(); my $verbosity = $dns->get_option( 'verbosity' ); $dns->set_option( verbosity => 1 + $verbosity ); Synchronous queries: my $res_hr = $dns->resolve( 'cpan.org', 'NS' ); # See below about encodings in “data”. my @ns = map { $dns->decode_name($_) } @{ $res_hr->data() }; Asynchronous queries use [the “Promise” pattern](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_promises): my $query1 = $dns->resolve_async( 'usa.gov', 'A' )->then( sub { my $data = shift()->data(); ... }, # success handler sub { ... }, # failure handler ); my $query2 = $dns->resolve_async( 'in-addr.arpa', 'NS' )->then( sub { ... }, sub { ... }, ); # As an alternative to wait(), see below for documentation on # the fd(), poll(), and process() methods. $dns->wait(); See `examples/` in the distribution for demonstrations of making this module interface with [AnyEvent](https://metacpan.org/pod/AnyEvent) or [IO::Async](https://metacpan.org/pod/IO::Async). # DESCRIPTION This library is a Perl interface to NLNetLabs’s widely-used [Unbound](https://nlnetlabs.nl/projects/unbound/) recursive DNS resolver. # METHODS ## _CLASS_->new() Instantiates this class. ## $result\_hr = _OBJ_->resolve( $NAME, $TYPE \[, $CLASS \] ) Runs a synchronous query for a given $NAME and $TYPE. $TYPE may be expressed numerically or, for convenience, as a string. $CLASS is optional and defaults to 1 (`IN`), which is probably what you want. Returns a [DNS::Unbound::Result](https://metacpan.org/pod/DNS::Unbound::Result) instance. **NOTE:** libunbound doesn’t seem to offer effective controls for timing out a synchronous query. If timeouts are relevant for you, you probably need to use `resolve_async()` instead. ## $query = _OBJ_->resolve\_async( $NAME, $TYPE \[, $CLASS \] ); Like `resolve()` but starts an asynchronous query rather than a synchronous one. This returns an instance of [DNS::Unbound::AsyncQuery](https://metacpan.org/pod/DNS::Unbound::AsyncQuery) (a subclass thereof, to be precise). [See below](#methods-for-dealing-with-asynchronous-queries) for the methods you’ll need to use in tandem with this one. ## _OBJ_->enable\_threads() Sets _OBJ_’s asynchronous queries to use threads rather than forking. Off by default. Throws an exception if called after an asynchronous query has already been sent. Returns _OBJ_. **NOTE:** Despite Perl’s iffy relationship with threads, this appears to work without issue. ## _OBJ_->set\_option( $NAME => $VALUE ) Sets a configuration option. Returns _OBJ_. Note that this is basically just a passthrough to the underlying `ub_ctx_set_option()` function and is thus subject to the same limitations as that function; for example, you can’t set `verbosity` after the configuration has been “finalized”. (So use `debuglevel()` for that instead.) ## $value = _OBJ_->get\_option( $NAME ) Gets a configuration option’s value. ## _OBJ_->debuglevel( $LEVEL ) Sets the debug level (an integer). Returns _OBJ_. As of libunbound v1.9.2, this is just a way to set the `verbosity` option regardless of whether the configuration is finalized. ## _OBJ_->debugout( $FD\_OR\_FH ) Accepts a file descriptor or Perl filehandle and designates that as the destination for libunbound diagnostic information. Returns _OBJ_. ## $str = _CLASS_->unbound\_version() Gives the libunbound version string. # METHODS FOR ALTERING RESOLVER LOGIC The following parallel their equivalents in libunbound. They return _OBJ_ and throw errors on failure. ## _OBJ_->hosts( $FILENAME ) ## _OBJ_->resolveconf( $FILENAME ) # METHODS FOR DEALING WITH ASYNCHRONOUS QUERIES Unless otherwise noted, the following methods correspond to their equivalents in libunbound. They return the same values as the libunbound equivalents. ## _OBJ_->poll() ## _OBJ_->fd() ## _OBJ_->wait() ## _OBJ_->process() ## _OBJ_->count\_pending\_queries() Returns the number of outstanding asynchronous queries. # METHODS FOR DEALING WITH DNSSEC The following correspond to their equivalents in libunbound and will only work if the underlying libunbound version supports them. They return _OBJ_ and throw errors on failure. ## _OBJ_->add\_ta() ## _OBJ_->add\_ta\_autr() ## _OBJ_->add\_ta\_file() ## _OBJ_->trustedkeys() # CONVENIENCE FUNCTIONS The following may be called either as object methods or as static functions (but not as class methods). In addition to these, [Socket](https://metacpan.org/pod/Socket) provides the `inet_ntoa()` and `inet_ntop()` functions for decoding the values of `A` and `AAAA` records. **NOTE:** Consider parsing [DNS::Unbound::Result](https://metacpan.org/pod/DNS::Unbound::Result)’s `answer_packet()` with [Net::DNS::Packet](https://metacpan.org/pod/Net::DNS::Packet) as a more robust, albeit heavier, way to parse query result data. ## $decoded = decode\_name($encoded) Decodes a DNS name. Useful for, e.g., `NS`, `CNAME`, and `PTR` query results. Note that this function’s return will normally include a trailing `.` because of the trailing NUL byte in an encoded DNS name. This is normal and expected. ## $strings\_ar = decode\_character\_strings($encoded) Decodes a list of character-strings into component strings, returned as an array reference. Useful for `TXT` query results. # LICENSE & COPYRIGHT Copyright 2019 Gasper Software Consulting. This library is licensed under the same terms as Perl itself. # REPOSITORY [https://github.com/FGasper/p5-DNS-Unbound](https://github.com/FGasper/p5-DNS-Unbound) # THANK YOU Special thanks to [ATOOMIC](https://metacpan.org/author/ATOOMIC) for making some helpful review notes.