Mail::SpamAssassin::DnsResolver(3)             User Contributed Perl Documentation            Mail::SpamAssassin::DnsResolver(3)



NAME
       Mail::SpamAssassin::DnsResolver - DNS resolution engine

DESCRIPTION
       This is a DNS resolution engine for SpamAssassin, implemented in order to reduce file descriptor usage by Net::DNS and
       avoid a response collision bug in that module.

METHODS
       $res->load_resolver()
           Load the "Net::DNS::Resolver" object.  Returns 0 if Net::DNS cannot be used, 1 if it is available.

       $resolver = $res->get_resolver()
           Return the "Net::DNS::Resolver" object.

       $res->nameservers()
           Wrapper for Net::DNS::Resolver->nameservers to get or set list of nameservers

       $res->connect_sock()
           Re-connect to the first nameserver listed in "/etc/resolv.conf" or similar platform-dependent source, as provided by
           "Net::DNS".

       $res->get_sock()
           Return the "IO::Socket::INET" object used to communicate with the nameserver.

       $packet = new_dns_packet ($host, $type, $class)
           A wrapper for "Net::DNS::Packet::new()" which traps a die thrown by it.

           To use this, change calls to "Net::DNS::Resolver::bgsend" from:

               $res->bgsend($hostname, $type);

           to:

               $res->bgsend(Mail::SpamAssassin::DnsResolver::new_dns_packet($hostname, $type, $class));

       $id = $res->bgsend($host, $type, $class, $cb)
           Quite similar to "Net::DNS::Resolver::bgsend", except that when a response packet eventually arrives, and
           "poll_responses" is called, the callback sub reference $cb will be called.

           Note that $type and $class may be "undef", in which case they will default to "A" and "IN", respectively.

           The callback sub will be called with three arguments -- the packet that was delivered, and an id string that
           fingerprints the query packet and the expected reply. The third argument is a timestamp (Unix time, floating point),
           captured at the time the packet was collected. It is expected that a closure callback be used, like so:

             my $id = $self->{resolver}->bgsend($host, $type, undef, sub {
                   my ($reply, $reply_id, $timestamp) = @_;
                   $self->got_a_reply ($reply, $reply_id);
                 });

           The callback can ignore the reply as an invalid packet sent to the listening port if the reply id does not match the
           return value from bgsend.

       $nfound = $res->poll_responses()
           See if there are any "bgsend" response packets ready, and return the number of such packets delivered to their
           callbacks.

       $res->bgabort()
           Call this to release pending requests from memory, when aborting backgrounded requests, or when the scan is complete.
           "Mail::SpamAssassin::PerMsgStatus::check" calls this before returning.

       $packet = $res->send($name, $type, $class)
           Emulates "Net::DNS::Resolver::send()".

       $res->errorstring()
           Little more than a stub for callers expecting this from "Net::DNS::Resolver".

           If called immediately after a call to $res->send this will return "query timed out" if the $res->send DNS query timed
           out.  Otherwise "unknown error or no error" will be returned.

           No other errors are reported.

       $res->finish_socket()
           Reset socket when done with it.

       $res->finish()
           Clean up for destruction.



perl v5.12.4                                               2011-06-06                         Mail::SpamAssassin::DnsResolver(3)