1Mail::SpamAssassin::DnsURseesrolCvoenrt(r3i)buted Perl DMoaciulm:e:nStpaatmiAosnsassin::DnsResolver(3)
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NAME

6       Mail::SpamAssassin::DnsResolver - DNS resolution engine
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DESCRIPTION

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

14       $res->load_resolver()
15           Load the "Net::DNS::Resolver" object.  Returns 0 if Net::DNS cannot
16           be used, 1 if it is available.
17
18       $resolver = $res->get_resolver()
19           Return the "Net::DNS::Resolver" object.
20
21       $res->configured_nameservers()
22           Get a list of nameservers as configured by dns_server directives or
23           as provided by Net::DNS, typically from /etc/resolv.conf
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25       $res->available_nameservers()
26           Get or set a list of currently available nameservers, which is
27           typically a known-to-be-good subset of configured nameservers
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29       $res->connect_sock()
30           Re-connect to the first nameserver listed in "/etc/resolv.conf" or
31           similar platform-dependent source, as provided by "Net::DNS".
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33       $res->get_sock()
34           Return the "IO::Socket::INET" object used to communicate with the
35           nameserver.
36
37       $packet = new_dns_packet ($domain, $type, $class)
38           A wrapper for "Net::DNS::Packet::new()" which traps a die thrown by
39           it.
40
41           To use this, change calls to "Net::DNS::Resolver::bgsend" from:
42
43               $res->bgsend($domain, $type);
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45           to:
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47               $res->bgsend(Mail::SpamAssassin::DnsResolver::new_dns_packet($domain, $type, $class));
48
49       $id = $res->bgsend($domain, $type, $class, $cb)
50           Quite similar to "Net::DNS::Resolver::bgsend", except that when a
51           reply packet eventually arrives, and "poll_responses" is called,
52           the callback sub reference $cb will be called.
53
54           Note that $type and $class may be "undef", in which case they will
55           default to "A" and "IN", respectively.
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57           The callback sub will be called with three arguments -- the packet
58           that was delivered, and an id string that fingerprints the query
59           packet and the expected reply. The third argument is a timestamp
60           (Unix time, floating point), captured at the time the packet was
61           collected. It is expected that a closure callback be used, like so:
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63             my $id = $self->{resolver}->bgsend($domain, $type, undef, sub {
64                   my ($reply, $reply_id, $timestamp) = @_;
65                   $self->got_a_reply ($reply, $reply_id);
66                 });
67
68           The callback can ignore the reply as an invalid packet sent to the
69           listening port if the reply id does not match the return value from
70           bgsend.
71
72       $id = $res->bgread()
73           Similar to "Net::DNS::Resolver::bgread".  Reads a DNS packet from a
74           supplied socket, decodes it, and returns a Net::DNS::Packet object
75           if successful.  Dies on error.
76
77       $nfound = $res->poll_responses()
78           See if there are any "bgsend" reply packets ready, and return the
79           number of such packets delivered to their callbacks.
80
81       $res->bgabort()
82           Call this to release pending requests from memory, when aborting
83           backgrounded requests, or when the scan is complete.
84           "Mail::SpamAssassin::PerMsgStatus::check" calls this before
85           returning.
86
87       $packet = $res->send($name, $type, $class)
88           Emulates "Net::DNS::Resolver::send()".
89
90           This subroutine is a simple synchronous leftover from SpamAssassin
91           version 3.3 and does not participate in packet query caching and
92           callback grouping as implemented by
93           AsyncLoop::bgsend_and_start_lookup().  As such it should be avoided
94           for mainstream usage.  Currently used through Mail::SPF::Server by
95           the SPF plugin.
96
97       $res->errorstring()
98           Little more than a stub for callers expecting this from
99           "Net::DNS::Resolver".
100
101           If called immediately after a call to $res->send this will return
102           "query timed out" if the $res->send DNS query timed out.  Otherwise
103           "unknown error or no error" will be returned.
104
105           No other errors are reported.
106
107       $res->finish_socket()
108           Reset socket when done with it.
109
110       $res->finish()
111           Clean up for destruction.
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115perl v5.30.1                      2020-02-03Mail::SpamAssassin::DnsResolver(3)
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