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1.1 |
=head1 NAME |
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AnyEvent::DNS - fully asynchronous DNS resolution |
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=head1 SYNOPSIS |
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use AnyEvent::DNS; |
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1.26 |
my $cv = AnyEvent->condvar; |
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1.30 |
AnyEvent::DNS::a "www.google.de", $cv; |
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1.26 |
# ... later |
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my @addrs = $cv->recv; |
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1.1 |
=head1 DESCRIPTION |
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This module offers both a number of DNS convenience functions as well |
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as a fully asynchronous and high-performance pure-perl stub resolver. |
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1.46 |
The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional |
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EDNS0 support for up to 4kiB datagrams and automatically falls back to |
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virtual circuit mode for large responses. |
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1.12 |
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1.1 |
=head2 CONVENIENCE FUNCTIONS |
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=over 4 |
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=cut |
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package AnyEvent::DNS; |
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1.3 |
no warnings; |
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1.1 |
use strict; |
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1.29 |
use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM); |
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1.35 |
use AnyEvent (); |
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1.6 |
use AnyEvent::Handle (); |
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1.37 |
use AnyEvent::Util qw(AF_INET6); |
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1.1 |
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1.39 |
our $VERSION = '1.0'; |
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1.32 |
our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222); |
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1.4 |
=item AnyEvent::DNS::a $domain, $cb->(@addrs) |
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Tries to resolve the given domain to IPv4 address(es). |
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1.17 |
=item AnyEvent::DNS::aaaa $domain, $cb->(@addrs) |
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Tries to resolve the given domain to IPv6 address(es). |
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1.4 |
=item AnyEvent::DNS::mx $domain, $cb->(@hostnames) |
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Tries to resolve the given domain into a sorted (lower preference value |
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first) list of domain names. |
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=item AnyEvent::DNS::ns $domain, $cb->(@hostnames) |
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Tries to resolve the given domain name into a list of name servers. |
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=item AnyEvent::DNS::txt $domain, $cb->(@hostnames) |
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Tries to resolve the given domain name into a list of text records. |
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=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr) |
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Tries to resolve the given service, protocol and domain name into a list |
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of service records. |
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1.24 |
Each srv_rr is an array reference with the following contents: |
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1.4 |
C<[$priority, $weight, $transport, $target]>. |
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They will be sorted with lowest priority, highest weight first (TODO: |
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1.24 |
should use the RFC algorithm to reorder same-priority records for weight). |
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1.4 |
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Example: |
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AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ... |
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# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] ) |
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1.48 |
=item AnyEvent::DNS::ptr $domain, $cb->(@hostnames) |
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Tries to make a PTR lookup on the given domain. See C<reverse_lookup> |
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and C<reverse_verify> if you want to resolve an IP address to a hostname |
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instead. |
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=item AnyEvent::DNS::any $domain, $cb->(@rrs) |
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Tries to resolve the given domain and passes all resource records found to |
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the callback. |
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=item AnyEvent::DNS::reverse_lookup $ipv4_or_6, $cb->(@hostnames) |
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1.4 |
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Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form) |
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1.48 |
into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses |
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transparently. |
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=item AnyEvent::DNS::reverse_verify $ipv4_or_6, $cb->(@hostnames) |
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The same as C<reverse_lookup>, but does forward-lookups to verify that |
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the resolved hostnames indeed point to the address, which makes spoofing |
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harder. |
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If you want to resolve an address into a hostname, this is the preferred |
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method: The DNS records could still change, but at least this function |
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verified that the hostname, at one point in the past, pointed at the IP |
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address you originally resolved. |
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1.4 |
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Example: |
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AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift }; |
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# => f.root-servers.net |
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=cut |
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1.38 |
sub MAX_PKT() { 4096 } # max packet size we advertise and accept |
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sub DOMAIN_PORT() { 53 } # if this changes drop me a note |
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1.4 |
sub resolver; |
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sub a($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "a", sub { |
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$cb->(map $_->[3], @_); |
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}); |
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} |
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1.17 |
sub aaaa($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "aaaa", sub { |
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$cb->(map $_->[3], @_); |
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}); |
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} |
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1.4 |
sub mx($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "mx", sub { |
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$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_); |
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}); |
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} |
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sub ns($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "ns", sub { |
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$cb->(map $_->[3], @_); |
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}); |
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} |
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sub txt($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "txt", sub { |
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$cb->(map $_->[3], @_); |
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}); |
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} |
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sub srv($$$$) { |
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my ($service, $proto, $domain, $cb) = @_; |
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# todo, ask for any and check glue records |
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resolver->resolve ("_$service._$proto.$domain" => "srv", sub { |
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$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] || $b->[4] <=> $a->[4] } @_); |
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}); |
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} |
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sub ptr($$) { |
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1.48 |
my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "ptr", sub { |
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$cb->(map $_->[3], @_); |
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}); |
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} |
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sub any($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "*", $cb); |
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} |
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# convert textual ip address into reverse lookup form |
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sub _munge_ptr($) { |
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my $ipn = $_[0] |
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or return; |
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my $ptr; |
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my $af = AnyEvent::Socket::address_family ($ipn); |
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1.4 |
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1.48 |
if ($af == AF_INET6) { |
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$ipn = substr $ipn, 0, 16; # anticipate future expansion |
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1.4 |
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1.48 |
# handle v4mapped and v4compat |
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if ($ipn =~ s/^\x00{10}(?:\xff\xff|\x00\x00)//) { |
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$af = AF_INET; |
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} else { |
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$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa."; |
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} |
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} |
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1.37 |
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if ($af == AF_INET) { |
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1.48 |
$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa."; |
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1.4 |
} |
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1.48 |
$ptr |
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} |
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sub reverse_lookup($$) { |
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my ($ip, $cb) = @_; |
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$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip) |
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or return $cb->(); |
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1.17 |
resolver->resolve ($ip => "ptr", sub { |
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1.4 |
$cb->(map $_->[3], @_); |
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}); |
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} |
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1.1 |
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1.48 |
sub reverse_verify($$) { |
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my ($ip, $cb) = @_; |
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my $ipn = AnyEvent::Socket::parse_address ($ip) |
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or return $cb->(); |
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my $af = AnyEvent::Socket::address_family ($ipn); |
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my @res; |
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my $cnt; |
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my $ptr = _munge_ptr $ipn |
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or return $cb->(); |
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$ip = AnyEvent::Socket::format_address ($ipn); # normalise into the same form |
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ptr $ptr, sub { |
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for my $name (@_) { |
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++$cnt; |
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# () around AF_INET to work around bug in 5.8 |
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resolver->resolve ($name => ($af == (AF_INET) ? "a" : "aaaa"), sub { |
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for (@_) { |
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push @res, $name |
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if $_->[3] eq $ip; |
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} |
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$cb->(@res) unless --$cnt; |
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}); |
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} |
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1.5 |
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1.48 |
$cb->() unless $cnt; |
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}; |
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1.5 |
} |
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1.36 |
################################################################################# |
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1.18 |
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1.15 |
=back |
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1.13 |
=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS |
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1.1 |
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=over 4 |
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1.11 |
=item $AnyEvent::DNS::EDNS0 |
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1.13 |
This variable decides whether dns_pack automatically enables EDNS0 |
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1.24 |
support. By default, this is disabled (C<0>), unless overridden by |
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1.40 |
C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use |
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1.21 |
EDNS0 in all requests. |
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1.11 |
|
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1.1 |
=cut |
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1.21 |
our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0 |
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1.10 |
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1.1 |
our %opcode_id = ( |
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query => 0, |
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iquery => 1, |
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status => 2, |
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1.5 |
notify => 4, |
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update => 5, |
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map +($_ => $_), 3, 6..15 |
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1.1 |
); |
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our %opcode_str = reverse %opcode_id; |
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our %rcode_id = ( |
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1.5 |
noerror => 0, |
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formerr => 1, |
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servfail => 2, |
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nxdomain => 3, |
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notimp => 4, |
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refused => 5, |
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yxdomain => 6, # Name Exists when it should not [RFC 2136] |
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yxrrset => 7, # RR Set Exists when it should not [RFC 2136] |
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nxrrset => 8, # RR Set that should exist does not [RFC 2136] |
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notauth => 9, # Server Not Authoritative for zone [RFC 2136] |
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notzone => 10, # Name not contained in zone [RFC 2136] |
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# EDNS0 16 BADVERS Bad OPT Version [RFC 2671] |
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# EDNS0 16 BADSIG TSIG Signature Failure [RFC 2845] |
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# EDNS0 17 BADKEY Key not recognized [RFC 2845] |
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# EDNS0 18 BADTIME Signature out of time window [RFC 2845] |
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# EDNS0 19 BADMODE Bad TKEY Mode [RFC 2930] |
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# EDNS0 20 BADNAME Duplicate key name [RFC 2930] |
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# EDNS0 21 BADALG Algorithm not supported [RFC 2930] |
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map +($_ => $_), 11..15 |
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1.1 |
); |
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our %rcode_str = reverse %rcode_id; |
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our %type_id = ( |
312 |
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a => 1, |
313 |
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ns => 2, |
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md => 3, |
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mf => 4, |
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cname => 5, |
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soa => 6, |
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mb => 7, |
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mg => 8, |
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mr => 9, |
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null => 10, |
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wks => 11, |
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ptr => 12, |
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hinfo => 13, |
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minfo => 14, |
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mx => 15, |
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txt => 16, |
328 |
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aaaa => 28, |
329 |
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srv => 33, |
330 |
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1.47 |
naptr => 35, # rfc2915 |
331 |
root |
1.5 |
opt => 41, |
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spf => 99, |
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tkey => 249, |
334 |
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tsig => 250, |
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ixfr => 251, |
336 |
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1.1 |
axfr => 252, |
337 |
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mailb => 253, |
338 |
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"*" => 255, |
339 |
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); |
340 |
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341 |
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our %type_str = reverse %type_id; |
342 |
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343 |
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our %class_id = ( |
344 |
root |
1.5 |
in => 1, |
345 |
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ch => 3, |
346 |
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hs => 4, |
347 |
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none => 254, |
348 |
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"*" => 255, |
349 |
root |
1.1 |
); |
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our %class_str = reverse %class_id; |
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353 |
root |
1.34 |
sub _enc_name($) { |
354 |
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1.29 |
pack "(C/a*)*", (split /\./, shift), "" |
355 |
root |
1.1 |
} |
356 |
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357 |
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sub _enc_qd() { |
358 |
root |
1.34 |
(_enc_name $_->[0]) . pack "nn", |
359 |
root |
1.1 |
($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}), |
360 |
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($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] || "in"}) |
361 |
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} |
362 |
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363 |
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sub _enc_rr() { |
364 |
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die "encoding of resource records is not supported"; |
365 |
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} |
366 |
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367 |
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=item $pkt = AnyEvent::DNS::dns_pack $dns |
368 |
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369 |
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Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly |
370 |
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recommended, then everything will be totally clear. Or maybe not. |
371 |
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372 |
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Resource records are not yet encodable. |
373 |
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374 |
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Examples: |
375 |
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376 |
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# very simple request, using lots of default values: |
377 |
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{ rd => 1, qd => [ [ "host.domain", "a"] ] } |
378 |
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379 |
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# more complex example, showing how flags etc. are named: |
380 |
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381 |
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{ |
382 |
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id => 10000, |
383 |
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op => "query", |
384 |
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rc => "nxdomain", |
385 |
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386 |
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# flags |
387 |
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qr => 1, |
388 |
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aa => 0, |
389 |
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tc => 0, |
390 |
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rd => 0, |
391 |
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ra => 0, |
392 |
root |
1.5 |
ad => 0, |
393 |
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cd => 0, |
394 |
root |
1.1 |
|
395 |
|
|
qd => [@rr], # query section |
396 |
|
|
an => [@rr], # answer section |
397 |
|
|
ns => [@rr], # authority section |
398 |
|
|
ar => [@rr], # additional records section |
399 |
|
|
} |
400 |
|
|
|
401 |
|
|
=cut |
402 |
|
|
|
403 |
|
|
sub dns_pack($) { |
404 |
|
|
my ($req) = @_; |
405 |
|
|
|
406 |
root |
1.7 |
pack "nn nnnn a* a* a* a* a*", |
407 |
root |
1.1 |
$req->{id}, |
408 |
|
|
|
409 |
|
|
! !$req->{qr} * 0x8000 |
410 |
|
|
+ $opcode_id{$req->{op}} * 0x0800 |
411 |
|
|
+ ! !$req->{aa} * 0x0400 |
412 |
|
|
+ ! !$req->{tc} * 0x0200 |
413 |
|
|
+ ! !$req->{rd} * 0x0100 |
414 |
|
|
+ ! !$req->{ra} * 0x0080 |
415 |
root |
1.5 |
+ ! !$req->{ad} * 0x0020 |
416 |
|
|
+ ! !$req->{cd} * 0x0010 |
417 |
root |
1.1 |
+ $rcode_id{$req->{rc}} * 0x0001, |
418 |
|
|
|
419 |
|
|
scalar @{ $req->{qd} || [] }, |
420 |
|
|
scalar @{ $req->{an} || [] }, |
421 |
|
|
scalar @{ $req->{ns} || [] }, |
422 |
root |
1.44 |
$EDNS0 + scalar @{ $req->{ar} || [] }, # EDNS0 option included here |
423 |
root |
1.1 |
|
424 |
|
|
(join "", map _enc_qd, @{ $req->{qd} || [] }), |
425 |
|
|
(join "", map _enc_rr, @{ $req->{an} || [] }), |
426 |
|
|
(join "", map _enc_rr, @{ $req->{ns} || [] }), |
427 |
root |
1.7 |
(join "", map _enc_rr, @{ $req->{ar} || [] }), |
428 |
|
|
|
429 |
root |
1.44 |
($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option |
430 |
root |
1.1 |
} |
431 |
|
|
|
432 |
|
|
our $ofs; |
433 |
|
|
our $pkt; |
434 |
|
|
|
435 |
|
|
# bitches |
436 |
root |
1.34 |
sub _dec_name { |
437 |
root |
1.1 |
my @res; |
438 |
|
|
my $redir; |
439 |
|
|
my $ptr = $ofs; |
440 |
|
|
my $cnt; |
441 |
|
|
|
442 |
|
|
while () { |
443 |
|
|
return undef if ++$cnt >= 256; # to avoid DoS attacks |
444 |
|
|
|
445 |
|
|
my $len = ord substr $pkt, $ptr++, 1; |
446 |
|
|
|
447 |
root |
1.34 |
if ($len >= 0xc0) { |
448 |
root |
1.1 |
$ptr++; |
449 |
|
|
$ofs = $ptr if $ptr > $ofs; |
450 |
|
|
$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff; |
451 |
|
|
} elsif ($len) { |
452 |
|
|
push @res, substr $pkt, $ptr, $len; |
453 |
|
|
$ptr += $len; |
454 |
|
|
} else { |
455 |
|
|
$ofs = $ptr if $ptr > $ofs; |
456 |
|
|
return join ".", @res; |
457 |
|
|
} |
458 |
|
|
} |
459 |
|
|
} |
460 |
|
|
|
461 |
|
|
sub _dec_qd { |
462 |
root |
1.34 |
my $qname = _dec_name; |
463 |
root |
1.1 |
my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4; |
464 |
|
|
[$qname, $type_str{$qt} || $qt, $class_str{$qc} || $qc] |
465 |
|
|
} |
466 |
|
|
|
467 |
|
|
our %dec_rr = ( |
468 |
root |
1.29 |
1 => sub { join ".", unpack "C4", $_ }, # a |
469 |
root |
1.34 |
2 => sub { local $ofs = $ofs - length; _dec_name }, # ns |
470 |
|
|
5 => sub { local $ofs = $ofs - length; _dec_name }, # cname |
471 |
root |
1.1 |
6 => sub { |
472 |
|
|
local $ofs = $ofs - length; |
473 |
root |
1.34 |
my $mname = _dec_name; |
474 |
|
|
my $rname = _dec_name; |
475 |
root |
1.1 |
($mname, $rname, unpack "NNNNN", substr $pkt, $ofs) |
476 |
|
|
}, # soa |
477 |
root |
1.29 |
11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks |
478 |
root |
1.34 |
12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr |
479 |
root |
1.29 |
13 => sub { unpack "C/a* C/a*", $_ }, # hinfo |
480 |
root |
1.34 |
15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx |
481 |
root |
1.29 |
16 => sub { unpack "(C/a*)*", $_ }, # txt |
482 |
root |
1.36 |
28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa |
483 |
root |
1.34 |
33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv |
484 |
root |
1.47 |
35 => sub { # naptr |
485 |
|
|
my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_; |
486 |
|
|
local $ofs = $ofs + $offset - length; |
487 |
|
|
($order, $preference, $flags, $service, $regexp, _dec_name) |
488 |
|
|
}, |
489 |
root |
1.29 |
99 => sub { unpack "(C/a*)*", $_ }, # spf |
490 |
root |
1.1 |
); |
491 |
|
|
|
492 |
|
|
sub _dec_rr { |
493 |
root |
1.34 |
my $name = _dec_name; |
494 |
root |
1.1 |
|
495 |
|
|
my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10; |
496 |
|
|
local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen; |
497 |
|
|
|
498 |
|
|
[ |
499 |
root |
1.34 |
$name, |
500 |
root |
1.1 |
$type_str{$rt} || $rt, |
501 |
|
|
$class_str{$rc} || $rc, |
502 |
|
|
($dec_rr{$rt} || sub { $_ })->(), |
503 |
|
|
] |
504 |
|
|
} |
505 |
|
|
|
506 |
|
|
=item $dns = AnyEvent::DNS::dns_unpack $pkt |
507 |
|
|
|
508 |
|
|
Unpacks a DNS packet into a perl data structure. |
509 |
|
|
|
510 |
|
|
Examples: |
511 |
|
|
|
512 |
root |
1.13 |
# an unsuccessful reply |
513 |
root |
1.1 |
{ |
514 |
|
|
'qd' => [ |
515 |
|
|
[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ] |
516 |
|
|
], |
517 |
|
|
'rc' => 'nxdomain', |
518 |
|
|
'ar' => [], |
519 |
|
|
'ns' => [ |
520 |
|
|
[ |
521 |
|
|
'uni-karlsruhe.de', |
522 |
|
|
'soa', |
523 |
|
|
'in', |
524 |
|
|
'netserv.rz.uni-karlsruhe.de', |
525 |
|
|
'hostmaster.rz.uni-karlsruhe.de', |
526 |
root |
1.13 |
2008052201, 10800, 1800, 2592000, 86400 |
527 |
root |
1.1 |
] |
528 |
|
|
], |
529 |
|
|
'tc' => '', |
530 |
|
|
'ra' => 1, |
531 |
|
|
'qr' => 1, |
532 |
|
|
'id' => 45915, |
533 |
|
|
'aa' => '', |
534 |
|
|
'an' => [], |
535 |
|
|
'rd' => 1, |
536 |
|
|
'op' => 'query' |
537 |
|
|
} |
538 |
|
|
|
539 |
|
|
# a successful reply |
540 |
|
|
|
541 |
|
|
{ |
542 |
|
|
'qd' => [ [ 'www.google.de', 'a', 'in' ] ], |
543 |
|
|
'rc' => 0, |
544 |
|
|
'ar' => [ |
545 |
|
|
[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ], |
546 |
|
|
[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ], |
547 |
|
|
[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ], |
548 |
|
|
], |
549 |
|
|
'ns' => [ |
550 |
|
|
[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ], |
551 |
|
|
[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ], |
552 |
|
|
], |
553 |
|
|
'tc' => '', |
554 |
|
|
'ra' => 1, |
555 |
|
|
'qr' => 1, |
556 |
|
|
'id' => 64265, |
557 |
|
|
'aa' => '', |
558 |
|
|
'an' => [ |
559 |
|
|
[ 'www.google.de', 'cname', 'in', 'www.google.com' ], |
560 |
|
|
[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ], |
561 |
|
|
[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ], |
562 |
|
|
[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ], |
563 |
|
|
], |
564 |
|
|
'rd' => 1, |
565 |
|
|
'op' => 0 |
566 |
|
|
} |
567 |
|
|
|
568 |
|
|
=cut |
569 |
|
|
|
570 |
|
|
sub dns_unpack($) { |
571 |
|
|
local $pkt = shift; |
572 |
|
|
my ($id, $flags, $qd, $an, $ns, $ar) |
573 |
|
|
= unpack "nn nnnn A*", $pkt; |
574 |
|
|
|
575 |
|
|
local $ofs = 6 * 2; |
576 |
|
|
|
577 |
|
|
{ |
578 |
|
|
id => $id, |
579 |
|
|
qr => ! ! ($flags & 0x8000), |
580 |
|
|
aa => ! ! ($flags & 0x0400), |
581 |
|
|
tc => ! ! ($flags & 0x0200), |
582 |
|
|
rd => ! ! ($flags & 0x0100), |
583 |
|
|
ra => ! ! ($flags & 0x0080), |
584 |
root |
1.5 |
ad => ! ! ($flags & 0x0020), |
585 |
|
|
cd => ! ! ($flags & 0x0010), |
586 |
root |
1.1 |
op => $opcode_str{($flags & 0x001e) >> 11}, |
587 |
|
|
rc => $rcode_str{($flags & 0x000f)}, |
588 |
|
|
|
589 |
|
|
qd => [map _dec_qd, 1 .. $qd], |
590 |
|
|
an => [map _dec_rr, 1 .. $an], |
591 |
|
|
ns => [map _dec_rr, 1 .. $ns], |
592 |
|
|
ar => [map _dec_rr, 1 .. $ar], |
593 |
|
|
} |
594 |
|
|
} |
595 |
|
|
|
596 |
|
|
############################################################################# |
597 |
|
|
|
598 |
|
|
=back |
599 |
|
|
|
600 |
|
|
=head2 THE AnyEvent::DNS RESOLVER CLASS |
601 |
|
|
|
602 |
root |
1.13 |
This is the class which does the actual protocol work. |
603 |
root |
1.1 |
|
604 |
|
|
=over 4 |
605 |
|
|
|
606 |
|
|
=cut |
607 |
|
|
|
608 |
|
|
use Carp (); |
609 |
|
|
use Scalar::Util (); |
610 |
|
|
use Socket (); |
611 |
|
|
|
612 |
|
|
our $NOW; |
613 |
|
|
|
614 |
root |
1.2 |
=item AnyEvent::DNS::resolver |
615 |
|
|
|
616 |
|
|
This function creates and returns a resolver that is ready to use and |
617 |
|
|
should mimic the default resolver for your system as good as possible. |
618 |
|
|
|
619 |
|
|
It only ever creates one resolver and returns this one on subsequent |
620 |
|
|
calls. |
621 |
|
|
|
622 |
|
|
Unless you have special needs, prefer this function over creating your own |
623 |
|
|
resolver object. |
624 |
|
|
|
625 |
|
|
=cut |
626 |
|
|
|
627 |
|
|
our $RESOLVER; |
628 |
|
|
|
629 |
|
|
sub resolver() { |
630 |
|
|
$RESOLVER || do { |
631 |
|
|
$RESOLVER = new AnyEvent::DNS; |
632 |
root |
1.14 |
$RESOLVER->os_config; |
633 |
root |
1.2 |
$RESOLVER |
634 |
|
|
} |
635 |
|
|
} |
636 |
|
|
|
637 |
root |
1.1 |
=item $resolver = new AnyEvent::DNS key => value... |
638 |
|
|
|
639 |
root |
1.6 |
Creates and returns a new resolver. |
640 |
root |
1.2 |
|
641 |
|
|
The following options are supported: |
642 |
root |
1.1 |
|
643 |
|
|
=over 4 |
644 |
|
|
|
645 |
|
|
=item server => [...] |
646 |
|
|
|
647 |
root |
1.41 |
A list of server addresses (default: C<v127.0.0.1>) in network format |
648 |
root |
1.42 |
(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and |
649 |
root |
1.41 |
IPv6 are supported). |
650 |
root |
1.1 |
|
651 |
|
|
=item timeout => [...] |
652 |
|
|
|
653 |
|
|
A list of timeouts to use (also determines the number of retries). To make |
654 |
|
|
three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2, |
655 |
|
|
5, 5]>, which is also the default. |
656 |
|
|
|
657 |
|
|
=item search => [...] |
658 |
|
|
|
659 |
|
|
The default search list of suffixes to append to a domain name (default: none). |
660 |
|
|
|
661 |
root |
1.2 |
=item ndots => $integer |
662 |
root |
1.1 |
|
663 |
|
|
The number of dots (default: C<1>) that a name must have so that the resolver |
664 |
|
|
tries to resolve the name without any suffixes first. |
665 |
|
|
|
666 |
root |
1.2 |
=item max_outstanding => $integer |
667 |
root |
1.1 |
|
668 |
root |
1.43 |
Most name servers do not handle many parallel requests very well. This |
669 |
|
|
option limits the number of outstanding requests to C<$integer> |
670 |
|
|
(default: C<10>), that means if you request more than this many requests, |
671 |
|
|
then the additional requests will be queued until some other requests have |
672 |
|
|
been resolved. |
673 |
root |
1.1 |
|
674 |
root |
1.13 |
=item reuse => $seconds |
675 |
|
|
|
676 |
root |
1.22 |
The number of seconds (default: C<300>) that a query id cannot be re-used |
677 |
|
|
after a timeout. If there as no time-out then query id's can be reused |
678 |
|
|
immediately. |
679 |
root |
1.13 |
|
680 |
root |
1.1 |
=back |
681 |
|
|
|
682 |
|
|
=cut |
683 |
|
|
|
684 |
|
|
sub new { |
685 |
|
|
my ($class, %arg) = @_; |
686 |
|
|
|
687 |
root |
1.38 |
# try to create a ipv4 and an ipv6 socket |
688 |
|
|
# only fail when we cnanot create either |
689 |
root |
1.1 |
|
690 |
root |
1.38 |
socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0; |
691 |
|
|
socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0; |
692 |
|
|
|
693 |
|
|
$fh4 || $fh6 |
694 |
|
|
or Carp::croak "unable to create either an IPv6 or an IPv4 socket"; |
695 |
root |
1.1 |
|
696 |
|
|
my $self = bless { |
697 |
root |
1.32 |
server => [], |
698 |
root |
1.1 |
timeout => [2, 5, 5], |
699 |
|
|
search => [], |
700 |
|
|
ndots => 1, |
701 |
|
|
max_outstanding => 10, |
702 |
root |
1.22 |
reuse => 300, # reuse id's after 5 minutes only, if possible |
703 |
root |
1.1 |
%arg, |
704 |
|
|
reuse_q => [], |
705 |
|
|
}, $class; |
706 |
|
|
|
707 |
|
|
# search should default to gethostname's domain |
708 |
|
|
# but perl lacks a good posix module |
709 |
|
|
|
710 |
|
|
Scalar::Util::weaken (my $wself = $self); |
711 |
root |
1.38 |
|
712 |
|
|
if ($fh4) { |
713 |
|
|
AnyEvent::Util::fh_nonblocking $fh4, 1; |
714 |
|
|
$self->{fh4} = $fh4; |
715 |
|
|
$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub { |
716 |
|
|
if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) { |
717 |
|
|
$wself->_recv ($pkt, $peer); |
718 |
|
|
} |
719 |
|
|
}); |
720 |
|
|
} |
721 |
|
|
|
722 |
|
|
if ($fh6) { |
723 |
|
|
$self->{fh6} = $fh6; |
724 |
|
|
AnyEvent::Util::fh_nonblocking $fh6, 1; |
725 |
|
|
$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub { |
726 |
|
|
if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) { |
727 |
|
|
$wself->_recv ($pkt, $peer); |
728 |
|
|
} |
729 |
|
|
}); |
730 |
|
|
} |
731 |
root |
1.1 |
|
732 |
|
|
$self->_compile; |
733 |
|
|
|
734 |
|
|
$self |
735 |
|
|
} |
736 |
|
|
|
737 |
|
|
=item $resolver->parse_resolv_conv ($string) |
738 |
|
|
|
739 |
root |
1.24 |
Parses the given string as if it were a F<resolv.conf> file. The following |
740 |
|
|
directives are supported (but not necessarily implemented). |
741 |
root |
1.1 |
|
742 |
|
|
C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>, |
743 |
|
|
C<options> (C<timeout>, C<attempts>, C<ndots>). |
744 |
|
|
|
745 |
|
|
Everything else is silently ignored. |
746 |
|
|
|
747 |
|
|
=cut |
748 |
|
|
|
749 |
|
|
sub parse_resolv_conf { |
750 |
|
|
my ($self, $resolvconf) = @_; |
751 |
|
|
|
752 |
|
|
$self->{server} = []; |
753 |
|
|
$self->{search} = []; |
754 |
|
|
|
755 |
|
|
my $attempts; |
756 |
|
|
|
757 |
|
|
for (split /\n/, $resolvconf) { |
758 |
|
|
if (/^\s*#/) { |
759 |
|
|
# comment |
760 |
|
|
} elsif (/^\s*nameserver\s+(\S+)\s*$/i) { |
761 |
|
|
my $ip = $1; |
762 |
root |
1.36 |
if (my $ipn = AnyEvent::Socket::parse_address ($ip)) { |
763 |
root |
1.25 |
push @{ $self->{server} }, $ipn; |
764 |
root |
1.1 |
} else { |
765 |
|
|
warn "nameserver $ip invalid and ignored\n"; |
766 |
|
|
} |
767 |
|
|
} elsif (/^\s*domain\s+(\S*)\s+$/i) { |
768 |
|
|
$self->{search} = [$1]; |
769 |
|
|
} elsif (/^\s*search\s+(.*?)\s*$/i) { |
770 |
|
|
$self->{search} = [split /\s+/, $1]; |
771 |
|
|
} elsif (/^\s*sortlist\s+(.*?)\s*$/i) { |
772 |
|
|
# ignored, NYI |
773 |
|
|
} elsif (/^\s*options\s+(.*?)\s*$/i) { |
774 |
|
|
for (split /\s+/, $1) { |
775 |
|
|
if (/^timeout:(\d+)$/) { |
776 |
|
|
$self->{timeout} = [$1]; |
777 |
|
|
} elsif (/^attempts:(\d+)$/) { |
778 |
|
|
$attempts = $1; |
779 |
|
|
} elsif (/^ndots:(\d+)$/) { |
780 |
|
|
$self->{ndots} = $1; |
781 |
|
|
} else { |
782 |
|
|
# debug, rotate, no-check-names, inet6 |
783 |
|
|
} |
784 |
|
|
} |
785 |
|
|
} |
786 |
|
|
} |
787 |
|
|
|
788 |
|
|
$self->{timeout} = [($self->{timeout}[0]) x $attempts] |
789 |
|
|
if $attempts; |
790 |
|
|
|
791 |
|
|
$self->_compile; |
792 |
|
|
} |
793 |
|
|
|
794 |
root |
1.14 |
=item $resolver->os_config |
795 |
root |
1.1 |
|
796 |
root |
1.24 |
Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various |
797 |
|
|
egregious hacks on windows to force the DNS servers and searchlist out of the system. |
798 |
root |
1.1 |
|
799 |
|
|
=cut |
800 |
|
|
|
801 |
root |
1.14 |
sub os_config { |
802 |
root |
1.1 |
my ($self) = @_; |
803 |
|
|
|
804 |
root |
1.32 |
$self->{server} = []; |
805 |
|
|
$self->{search} = []; |
806 |
|
|
|
807 |
root |
1.35 |
if (AnyEvent::WIN32 || $^O =~ /cygwin/i) { |
808 |
root |
1.32 |
no strict 'refs'; |
809 |
|
|
|
810 |
|
|
# there are many options to find the current nameservers etc. on windows |
811 |
|
|
# all of them don't work consistently: |
812 |
|
|
# - the registry thing needs separate code on win32 native vs. cygwin |
813 |
|
|
# - the registry layout differs between windows versions |
814 |
|
|
# - calling windows api functions doesn't work on cygwin |
815 |
|
|
# - ipconfig uses locale-specific messages |
816 |
|
|
|
817 |
|
|
# we use ipconfig parsing because, despite all it's brokenness, |
818 |
|
|
# it seems most stable in practise. |
819 |
|
|
# for good measure, we append a fallback nameserver to our list. |
820 |
root |
1.14 |
|
821 |
|
|
if (open my $fh, "ipconfig /all |") { |
822 |
root |
1.32 |
# parsing strategy: we go through the output and look for |
823 |
|
|
# :-lines with DNS in them. everything in those is regarded as |
824 |
|
|
# either a nameserver (if it parses as an ip address), or a suffix |
825 |
|
|
# (all else). |
826 |
root |
1.14 |
|
827 |
root |
1.32 |
my $dns; |
828 |
root |
1.14 |
while (<$fh>) { |
829 |
root |
1.32 |
if (s/^\s.*\bdns\b.*://i) { |
830 |
|
|
$dns = 1; |
831 |
|
|
} elsif (/^\S/ || /^\s[^:]{16,}: /) { |
832 |
|
|
$dns = 0; |
833 |
|
|
} |
834 |
|
|
if ($dns && /^\s*(\S+)\s*$/) { |
835 |
|
|
my $s = $1; |
836 |
|
|
$s =~ s/%\d+(?!\S)//; # get rid of scope id |
837 |
root |
1.36 |
if (my $ipn = AnyEvent::Socket::parse_address ($s)) { |
838 |
root |
1.32 |
push @{ $self->{server} }, $ipn; |
839 |
|
|
} else { |
840 |
|
|
push @{ $self->{search} }, $s; |
841 |
root |
1.14 |
} |
842 |
|
|
} |
843 |
|
|
} |
844 |
|
|
|
845 |
root |
1.32 |
# always add one fallback server |
846 |
|
|
push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK]; |
847 |
root |
1.14 |
|
848 |
|
|
$self->_compile; |
849 |
|
|
} |
850 |
|
|
} else { |
851 |
|
|
# try resolv.conf everywhere |
852 |
root |
1.1 |
|
853 |
root |
1.14 |
if (open my $fh, "</etc/resolv.conf") { |
854 |
|
|
local $/; |
855 |
|
|
$self->parse_resolv_conf (<$fh>); |
856 |
|
|
} |
857 |
|
|
} |
858 |
root |
1.1 |
} |
859 |
|
|
|
860 |
|
|
sub _compile { |
861 |
|
|
my $self = shift; |
862 |
|
|
|
863 |
root |
1.38 |
my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }]; |
864 |
|
|
my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }]; |
865 |
root |
1.32 |
|
866 |
|
|
unless (@{ $self->{server} }) { |
867 |
|
|
# use 127.0.0.1 by default, and one opendns nameserver as fallback |
868 |
|
|
$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]]; |
869 |
|
|
} |
870 |
|
|
|
871 |
root |
1.1 |
my @retry; |
872 |
|
|
|
873 |
|
|
for my $timeout (@{ $self->{timeout} }) { |
874 |
|
|
for my $server (@{ $self->{server} }) { |
875 |
|
|
push @retry, [$server, $timeout]; |
876 |
|
|
} |
877 |
|
|
} |
878 |
|
|
|
879 |
|
|
$self->{retry} = \@retry; |
880 |
|
|
} |
881 |
|
|
|
882 |
root |
1.6 |
sub _feed { |
883 |
|
|
my ($self, $res) = @_; |
884 |
|
|
|
885 |
|
|
$res = dns_unpack $res |
886 |
|
|
or return; |
887 |
|
|
|
888 |
|
|
my $id = $self->{id}{$res->{id}}; |
889 |
|
|
|
890 |
|
|
return unless ref $id; |
891 |
|
|
|
892 |
|
|
$NOW = time; |
893 |
|
|
$id->[1]->($res); |
894 |
|
|
} |
895 |
|
|
|
896 |
root |
1.1 |
sub _recv { |
897 |
root |
1.38 |
my ($self, $pkt, $peer) = @_; |
898 |
root |
1.1 |
|
899 |
root |
1.32 |
# we ignore errors (often one gets port unreachable, but there is |
900 |
|
|
# no good way to take advantage of that. |
901 |
root |
1.1 |
|
902 |
root |
1.38 |
my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer); |
903 |
|
|
|
904 |
|
|
return unless $port == 53 && grep $_ eq $host, @{ $self->{server} }; |
905 |
root |
1.1 |
|
906 |
root |
1.38 |
$self->_feed ($pkt); |
907 |
root |
1.1 |
} |
908 |
|
|
|
909 |
root |
1.22 |
sub _free_id { |
910 |
|
|
my ($self, $id, $timeout) = @_; |
911 |
|
|
|
912 |
|
|
if ($timeout) { |
913 |
|
|
# we need to block the id for a while |
914 |
|
|
$self->{id}{$id} = 1; |
915 |
|
|
push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id]; |
916 |
|
|
} else { |
917 |
|
|
# we can quickly recycle the id |
918 |
|
|
delete $self->{id}{$id}; |
919 |
|
|
} |
920 |
|
|
|
921 |
|
|
--$self->{outstanding}; |
922 |
|
|
$self->_scheduler; |
923 |
|
|
} |
924 |
|
|
|
925 |
|
|
# execute a single request, involves sending it with timeouts to multiple servers |
926 |
root |
1.1 |
sub _exec { |
927 |
root |
1.22 |
my ($self, $req) = @_; |
928 |
|
|
|
929 |
|
|
my $retry; # of retries |
930 |
|
|
my $do_retry; |
931 |
|
|
|
932 |
|
|
$do_retry = sub { |
933 |
|
|
my $retry_cfg = $self->{retry}[$retry++] |
934 |
|
|
or do { |
935 |
|
|
# failure |
936 |
|
|
$self->_free_id ($req->[2], $retry > 1); |
937 |
|
|
undef $do_retry; return $req->[1]->(); |
938 |
|
|
}; |
939 |
root |
1.1 |
|
940 |
|
|
my ($server, $timeout) = @$retry_cfg; |
941 |
|
|
|
942 |
|
|
$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub { |
943 |
|
|
$NOW = time; |
944 |
|
|
|
945 |
|
|
# timeout, try next |
946 |
root |
1.22 |
&$do_retry; |
947 |
root |
1.1 |
}), sub { |
948 |
|
|
my ($res) = @_; |
949 |
|
|
|
950 |
root |
1.6 |
if ($res->{tc}) { |
951 |
|
|
# success, but truncated, so use tcp |
952 |
root |
1.38 |
AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub { |
953 |
root |
1.6 |
my ($fh) = @_ |
954 |
root |
1.22 |
or return &$do_retry; |
955 |
root |
1.6 |
|
956 |
|
|
my $handle = new AnyEvent::Handle |
957 |
|
|
fh => $fh, |
958 |
|
|
on_error => sub { |
959 |
|
|
# failure, try next |
960 |
root |
1.22 |
&$do_retry; |
961 |
root |
1.6 |
}; |
962 |
|
|
|
963 |
|
|
$handle->push_write (pack "n/a", $req->[0]); |
964 |
root |
1.27 |
$handle->push_read (chunk => 2, sub { |
965 |
|
|
$handle->unshift_read (chunk => (unpack "n", $_[1]), sub { |
966 |
root |
1.6 |
$self->_feed ($_[1]); |
967 |
|
|
}); |
968 |
|
|
}); |
969 |
|
|
shutdown $fh, 1; |
970 |
|
|
|
971 |
root |
1.17 |
}, sub { $timeout }); |
972 |
root |
1.1 |
|
973 |
root |
1.6 |
} else { |
974 |
|
|
# success |
975 |
root |
1.22 |
$self->_free_id ($req->[2], $retry > 1); |
976 |
|
|
undef $do_retry; return $req->[1]->($res); |
977 |
root |
1.6 |
} |
978 |
root |
1.1 |
}]; |
979 |
root |
1.38 |
|
980 |
|
|
my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server); |
981 |
|
|
|
982 |
root |
1.39 |
my $fh = AF_INET == Socket::sockaddr_family ($sa) |
983 |
root |
1.38 |
? $self->{fh4} : $self->{fh6} |
984 |
|
|
or return &$do_retry; |
985 |
root |
1.1 |
|
986 |
root |
1.38 |
send $fh, $req->[0], 0, $sa; |
987 |
root |
1.22 |
}; |
988 |
root |
1.1 |
|
989 |
root |
1.22 |
&$do_retry; |
990 |
root |
1.1 |
} |
991 |
|
|
|
992 |
|
|
sub _scheduler { |
993 |
|
|
my ($self) = @_; |
994 |
|
|
|
995 |
|
|
$NOW = time; |
996 |
|
|
|
997 |
|
|
# first clear id reuse queue |
998 |
|
|
delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] } |
999 |
root |
1.13 |
while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW; |
1000 |
root |
1.1 |
|
1001 |
|
|
while ($self->{outstanding} < $self->{max_outstanding}) { |
1002 |
root |
1.13 |
|
1003 |
|
|
if (@{ $self->{reuse_q} } >= 30000) { |
1004 |
|
|
# we ran out of ID's, wait a bit |
1005 |
|
|
$self->{reuse_to} ||= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub { |
1006 |
|
|
delete $self->{reuse_to}; |
1007 |
|
|
$self->_scheduler; |
1008 |
|
|
}); |
1009 |
|
|
last; |
1010 |
|
|
} |
1011 |
|
|
|
1012 |
root |
1.1 |
my $req = shift @{ $self->{queue} } |
1013 |
|
|
or last; |
1014 |
|
|
|
1015 |
|
|
while () { |
1016 |
|
|
$req->[2] = int rand 65536; |
1017 |
|
|
last unless exists $self->{id}{$req->[2]}; |
1018 |
|
|
} |
1019 |
|
|
|
1020 |
root |
1.22 |
++$self->{outstanding}; |
1021 |
root |
1.1 |
$self->{id}{$req->[2]} = 1; |
1022 |
|
|
substr $req->[0], 0, 2, pack "n", $req->[2]; |
1023 |
|
|
|
1024 |
root |
1.22 |
$self->_exec ($req); |
1025 |
root |
1.1 |
} |
1026 |
|
|
} |
1027 |
|
|
|
1028 |
|
|
=item $resolver->request ($req, $cb->($res)) |
1029 |
|
|
|
1030 |
|
|
Sends a single request (a hash-ref formated as specified for |
1031 |
root |
1.3 |
C<dns_pack>) to the configured nameservers including |
1032 |
root |
1.1 |
retries. Calls the callback with the decoded response packet if a reply |
1033 |
|
|
was received, or no arguments on timeout. |
1034 |
|
|
|
1035 |
|
|
=cut |
1036 |
|
|
|
1037 |
|
|
sub request($$) { |
1038 |
|
|
my ($self, $req, $cb) = @_; |
1039 |
|
|
|
1040 |
root |
1.3 |
push @{ $self->{queue} }, [dns_pack $req, $cb]; |
1041 |
root |
1.1 |
$self->_scheduler; |
1042 |
|
|
} |
1043 |
|
|
|
1044 |
|
|
=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr)) |
1045 |
|
|
|
1046 |
root |
1.44 |
Queries the DNS for the given domain name C<$qname> of type C<$qtype>. |
1047 |
|
|
|
1048 |
|
|
A C<$qtype> is either a numerical query type (e.g. C<1> for A recods) or |
1049 |
|
|
a lowercase name (you have to look at the source to see which aliases are |
1050 |
|
|
supported, but all types from RFC 1034, C<aaaa>, C<srv>, C<spf> and a few |
1051 |
|
|
more are known to this module). A qtype of "*" is supported and means |
1052 |
|
|
"any" record type. |
1053 |
root |
1.1 |
|
1054 |
|
|
The callback will be invoked with a list of matching result records or |
1055 |
|
|
none on any error or if the name could not be found. |
1056 |
|
|
|
1057 |
|
|
CNAME chains (although illegal) are followed up to a length of 8. |
1058 |
|
|
|
1059 |
root |
1.44 |
The callback will be invoked with an result code in string form (noerror, |
1060 |
|
|
formerr, servfail, nxdomain, notimp, refused and so on), or numerical |
1061 |
|
|
form if the result code is not supported. The remaining arguments are |
1062 |
|
|
arraryefs of the form C<[$name, $type, $class, @data>], where C<$name> is |
1063 |
|
|
the domain name, C<$type> a type string or number, C<$class> a class name |
1064 |
|
|
and @data is resource-record-dependent data. For C<a> records, this will |
1065 |
|
|
be the textual IPv4 addresses, for C<ns> or C<cname> records this will be |
1066 |
|
|
a domain name, for C<txt> records these are all the strings and so on. |
1067 |
|
|
|
1068 |
|
|
All types mentioned in RFC 1034, C<aaaa>, C<srv> and C<spf> are |
1069 |
|
|
decoded. All resource records not known to this module will just return |
1070 |
|
|
the raw C<rdata> field as fourth entry. |
1071 |
|
|
|
1072 |
root |
1.24 |
Note that this resolver is just a stub resolver: it requires a name server |
1073 |
root |
1.3 |
supporting recursive queries, will not do any recursive queries itself and |
1074 |
|
|
is not secure when used against an untrusted name server. |
1075 |
|
|
|
1076 |
root |
1.1 |
The following options are supported: |
1077 |
|
|
|
1078 |
|
|
=over 4 |
1079 |
|
|
|
1080 |
|
|
=item search => [$suffix...] |
1081 |
|
|
|
1082 |
|
|
Use the given search list (which might be empty), by appending each one |
1083 |
|
|
in turn to the C<$qname>. If this option is missing then the configured |
1084 |
|
|
C<ndots> and C<search> define its value. If the C<$qname> ends in a dot, |
1085 |
root |
1.2 |
then the searchlist will be ignored. |
1086 |
root |
1.1 |
|
1087 |
|
|
=item accept => [$type...] |
1088 |
|
|
|
1089 |
|
|
Lists the acceptable result types: only result types in this set will be |
1090 |
|
|
accepted and returned. The default includes the C<$qtype> and nothing |
1091 |
root |
1.44 |
else. If this list includes C<cname>, then CNAME-chains will not be |
1092 |
|
|
followed (because you asked for the CNAME record). |
1093 |
root |
1.1 |
|
1094 |
|
|
=item class => "class" |
1095 |
|
|
|
1096 |
|
|
Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for |
1097 |
root |
1.2 |
hesiod are the only ones making sense). The default is "in", of course. |
1098 |
root |
1.1 |
|
1099 |
|
|
=back |
1100 |
|
|
|
1101 |
|
|
Examples: |
1102 |
|
|
|
1103 |
root |
1.46 |
# full example, you can paste this into perl: |
1104 |
root |
1.45 |
use Data::Dumper; |
1105 |
|
|
use AnyEvent::DNS; |
1106 |
|
|
AnyEvent::DNS::resolver->resolve ( |
1107 |
|
|
"google.com", "*", my $cv = AnyEvent->condvar); |
1108 |
|
|
warn Dumper [$cv->recv]; |
1109 |
|
|
|
1110 |
|
|
# shortened result: |
1111 |
|
|
# [ |
1112 |
|
|
# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com', |
1113 |
|
|
# 2008052701, 7200, 1800, 1209600, 300 ], |
1114 |
|
|
# [ |
1115 |
|
|
# 'google.com', 'txt', 'in', |
1116 |
|
|
# 'v=spf1 include:_netblocks.google.com ~all' |
1117 |
|
|
# ], |
1118 |
|
|
# [ 'google.com', 'a', 'in', '64.233.187.99' ], |
1119 |
|
|
# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ], |
1120 |
|
|
# [ 'google.com', 'ns', 'in', 'ns2.google.com' ], |
1121 |
|
|
# ] |
1122 |
|
|
|
1123 |
|
|
# resolve a records: |
1124 |
|
|
$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] }); |
1125 |
|
|
|
1126 |
|
|
# result: |
1127 |
|
|
# [ |
1128 |
|
|
# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ] |
1129 |
|
|
# ] |
1130 |
root |
1.1 |
|
1131 |
root |
1.45 |
# resolve any records, but return only a and aaaa records: |
1132 |
root |
1.1 |
$res->resolve ("test1.laendle", "*", |
1133 |
|
|
accept => ["a", "aaaa"], |
1134 |
|
|
sub { |
1135 |
|
|
warn Dumper [@_]; |
1136 |
|
|
} |
1137 |
|
|
); |
1138 |
|
|
|
1139 |
root |
1.45 |
# result: |
1140 |
|
|
# [ |
1141 |
|
|
# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ], |
1142 |
|
|
# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ] |
1143 |
|
|
# ] |
1144 |
root |
1.1 |
|
1145 |
|
|
=cut |
1146 |
|
|
|
1147 |
|
|
sub resolve($%) { |
1148 |
|
|
my $cb = pop; |
1149 |
|
|
my ($self, $qname, $qtype, %opt) = @_; |
1150 |
|
|
|
1151 |
|
|
my @search = $qname =~ s/\.$// |
1152 |
|
|
? "" |
1153 |
|
|
: $opt{search} |
1154 |
|
|
? @{ $opt{search} } |
1155 |
|
|
: ($qname =~ y/.//) >= $self->{ndots} |
1156 |
|
|
? ("", @{ $self->{search} }) |
1157 |
|
|
: (@{ $self->{search} }, ""); |
1158 |
|
|
|
1159 |
|
|
my $class = $opt{class} || "in"; |
1160 |
|
|
|
1161 |
|
|
my %atype = $opt{accept} |
1162 |
|
|
? map +($_ => 1), @{ $opt{accept} } |
1163 |
|
|
: ($qtype => 1); |
1164 |
|
|
|
1165 |
|
|
# advance in searchlist |
1166 |
root |
1.22 |
my ($do_search, $do_req); |
1167 |
|
|
|
1168 |
|
|
$do_search = sub { |
1169 |
root |
1.1 |
@search |
1170 |
root |
1.22 |
or (undef $do_search), (undef $do_req), return $cb->(); |
1171 |
root |
1.1 |
|
1172 |
root |
1.4 |
(my $name = lc "$qname." . shift @search) =~ s/\.$//; |
1173 |
root |
1.1 |
my $depth = 2; |
1174 |
|
|
|
1175 |
|
|
# advance in cname-chain |
1176 |
root |
1.22 |
$do_req = sub { |
1177 |
root |
1.1 |
$self->request ({ |
1178 |
|
|
rd => 1, |
1179 |
|
|
qd => [[$name, $qtype, $class]], |
1180 |
|
|
}, sub { |
1181 |
|
|
my ($res) = @_ |
1182 |
|
|
or return $do_search->(); |
1183 |
|
|
|
1184 |
|
|
my $cname; |
1185 |
|
|
|
1186 |
|
|
while () { |
1187 |
root |
1.2 |
# results found? |
1188 |
root |
1.4 |
my @rr = grep $name eq lc $_->[0] && ($atype{"*"} || $atype{$_->[1]}), @{ $res->{an} }; |
1189 |
root |
1.1 |
|
1190 |
root |
1.22 |
(undef $do_search), (undef $do_req), return $cb->(@rr) |
1191 |
root |
1.1 |
if @rr; |
1192 |
|
|
|
1193 |
|
|
# see if there is a cname we can follow |
1194 |
root |
1.4 |
my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} }; |
1195 |
root |
1.1 |
|
1196 |
|
|
if (@rr) { |
1197 |
|
|
$depth-- |
1198 |
|
|
or return $do_search->(); # cname chain too long |
1199 |
|
|
|
1200 |
|
|
$cname = 1; |
1201 |
|
|
$name = $rr[0][3]; |
1202 |
|
|
|
1203 |
|
|
} elsif ($cname) { |
1204 |
|
|
# follow the cname |
1205 |
|
|
return $do_req->(); |
1206 |
|
|
|
1207 |
|
|
} else { |
1208 |
root |
1.2 |
# no, not found anything |
1209 |
root |
1.1 |
return $do_search->(); |
1210 |
|
|
} |
1211 |
|
|
} |
1212 |
|
|
}); |
1213 |
|
|
}; |
1214 |
|
|
|
1215 |
|
|
$do_req->(); |
1216 |
|
|
}; |
1217 |
|
|
|
1218 |
|
|
$do_search->(); |
1219 |
|
|
} |
1220 |
|
|
|
1221 |
root |
1.17 |
use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end |
1222 |
|
|
|
1223 |
root |
1.1 |
1; |
1224 |
|
|
|
1225 |
|
|
=back |
1226 |
|
|
|
1227 |
|
|
=head1 AUTHOR |
1228 |
|
|
|
1229 |
|
|
Marc Lehmann <schmorp@schmorp.de> |
1230 |
|
|
http://home.schmorp.de/ |
1231 |
|
|
|
1232 |
|
|
=cut |
1233 |
|
|
|