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Mail::SpamAssassin::DnUseroContributed Perl 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->configured_nameservers()
           Get a list of nameservers as configured by dns_server directives or
           as provided by Net::DNS, typically from /etc/resolv.conf
       $res->available_nameservers()
           Get or set a list of currently available nameservers, which is
           typically a known-to-be-good subset of configured 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.
       $packet = new_dns_packet ($domain, $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:
               $res->bgsend($domain, $type);
           to:
               $res->bgsend(Mail::SpamAssassin::DnsResolver::new_dns_packet($domain, $type, $class));
       $id = $res->bgsend($domain, $type, $class, $cb)
           Quite similar to "Net::DNS::Resolver::bgsend", except that when a
           reply 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 = $self->{resolver}->bgsend($domain, $type, undef, sub {
                   my ($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.
       $id = $res->bgread()
           Similar to "Net::DNS::Resolver::bgread".  Reads a DNS packet from a
           supplied socket, decodes it, and returns a Net::DNS::Packet object
           if successful.  Dies on error.
       $nfound = $res->poll_responses()
           See if there are any "bgsend" reply 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()".
           This subroutine is a simple synchronous leftover from SpamAssassin
           version 3.3 and does not participate in packet query caching and
           callback grouping as implemented by
           AsyncLoop::bgsend_and_start_lookup().  As such it should be avoided
           for mainstream usage.  Currently used through Mail::SPF::Server by
           the SPF plugin.
       $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 v5.26.3                      2021-04-09Mail::SpamAssassin::DnsResolver(3)