1Mail::SpamAssassin::DnsURseesrolCvoenrt(r3i)buted Perl DMoaciulm:e:nStpaatmiAosnsassin::DnsResolver(3)
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6 Mail::SpamAssassin::DnsResolver - DNS resolution engine
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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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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 $resolver = $res->get_resolver()
19 Return the "Net::DNS::Resolver" object.
20 $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
24 $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
28 $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".
32 $res->get_sock()
34 Return the "IO::Socket::INET" object used to communicate with the
35 nameserver.
36 $packet = new_dns_packet ($domain, $type, $class)
38 A wrapper for "Net::DNS::Packet::new()" which traps a die thrown by
39 it.
40 To use this, change calls to "Net::DNS::Resolver::bgsend" from:
42 $res->bgsend($domain, $type);
44 to:
46 $res->bgsend(Mail::SpamAssassin::DnsResolver::new_dns_packet($domain, $type, $class));
48 $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 Note that $type and $class may be "undef", in which case they will
55 default to "A" and "IN", respectively.
56 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:
62 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 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 $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 $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 $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 $packet = $res->send($name, $type, $class)
88 Emulates "Net::DNS::Resolver::send()".
89 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 $res->errorstring()
98 Little more than a stub for callers expecting this from
99 "Net::DNS::Resolver".
100 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 No other errors are reported.
106 $res->finish_socket()
108 Reset socket when done with it.
109 $res->finish()
111 Clean up for destruction.
112perl v5.34.0 2021-07-23Mail::SpamAssassin::DnsResolver(3)