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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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=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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1.12 |
The stub resolver supports DNS over UDP, optional EDNS0 support for up to |
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4kiB datagrams and automatically falls back to virtual circuit mode for |
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large responses. |
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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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1.6 |
use AnyEvent::Handle (); |
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1.1 |
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1.18 |
=item AnyEvent::DNS::addr $node, $service, $proto, $family, $type, $cb->([$family, $type, $proto, $sockaddr], ...) |
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1.4 |
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1.18 |
Tries to resolve the given nodename and service name into protocol families |
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and sockaddr structures usable to connect to this node and service in a |
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protocol-independent way. It works remotely similar to the getaddrinfo |
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posix function. |
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C<$node> is either an IPv4 or IPv6 address or a hostname, C<$service> is |
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either a service name (port name from F</etc/services>) or a numerical |
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port number. If both C<$node> and C<$service> are names, then SRV records |
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will be consulted to find the real service, otherwise they will be |
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used as-is. If you know that the service name is not in your services |
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database, then you cna specify the service in the format C<name=port> |
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(e.g. C<http=80>). |
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C<$proto> must be a protocol name, currently C<tcp>, C<udp> or |
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C<sctp>. The default is C<tcp>. |
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C<$family> must be either C<0> (meaning any protocol is ok), C<4> (use |
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1.20 |
only IPv4) or C<6> (use only IPv6). This setting might be influenced by |
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C<$ENV{PERL_ANYEVENT_PROTOCOLS}>. |
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1.18 |
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C<$type> must be C<SOCK_STREAM>, C<SOCK_DGRAM> or C<SOCK_SEQPACKET> (or |
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C<undef> in which case it gets automatically chosen). |
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The callback will receive zero or more array references that contain |
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C<$family, $type, $proto> for use in C<socket> and a binary |
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C<$sockaddr> for use in C<connect> (or C<bind>). |
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The application should try these in the order given. |
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1.4 |
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Example: |
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1.18 |
AnyEvent::DNS::addr "google.com", "http", 0, undef, undef, sub { ... }; |
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1.4 |
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=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, $cb->(@srv_rr) |
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Tries to resolve the given service, protocol and domain name into a list |
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of service records. |
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Each srv_rr is an arrayref with the following contents: |
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C<[$priority, $weight, $transport, $target]>. |
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They will be sorted with lowest priority, highest weight first (TODO: |
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should use the rfc algorithm to reorder same-priority records for weight). |
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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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=item AnyEvent::DNS::ptr $ipv4_or_6, $cb->(@hostnames) |
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Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form) |
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into it's hostname(s). |
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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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1.5 |
=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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1.4 |
=cut |
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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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my ($ip, $cb) = @_; |
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1.17 |
$ip = AnyEvent::Socket::parse_ip ($ip) |
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or return $cb->(); |
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1.4 |
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1.17 |
if (4 == length $ip) { |
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$ip = join ".", (reverse split /\./, $ip), "in-addr.arpa."; |
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1.4 |
} else { |
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1.17 |
$ip = join ".", (reverse split //, unpack "H*", $ip), "ip6.arpa."; |
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1.4 |
} |
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1.17 |
resolver->resolve ($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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1.5 |
sub any($$) { |
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my ($domain, $cb) = @_; |
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resolver->resolve ($domain => "*", $cb); |
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} |
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1.18 |
############################################################################# |
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# $port, $host |
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sub pack_sockaddr_in6($$) { |
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pack "nnN a16 N", |
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Socket::AF_INET6, |
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$_[0], # port |
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0, # flowinfo |
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$_[1], # addr |
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0 # scope id |
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} |
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sub addr($$$$$$) { |
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my ($node, $service, $proto, $family, $type, $cb) = @_; |
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unless (eval { &Socket::AF_INET6 }) { |
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$family != 6 |
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or return $cb->(); |
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1.19 |
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$family ||= 4; |
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1.18 |
} |
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1.20 |
$cb->() if $family == 4 && !$AnyEvent::PROTOCOL{ipv4}; |
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$cb->() if $family == 6 && !$AnyEvent::PROTOCOL{ipv6}; |
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$family ||=4 unless $AnyEvent::PROTOCOL{ipv6}; |
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$family ||=6 unless $AnyEvent::PROTOCOL{ipv4}; |
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1.18 |
$proto ||= "tcp"; |
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$type ||= $proto eq "udp" ? Socket::SOCK_DGRAM : Socket::SOCK_STREAM; |
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my $proton = (getprotobyname $proto)[2] |
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or Carp::croak "$proto: protocol unknown"; |
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my $port; |
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if ($service =~ /^(\S+)=(\d+)$/) { |
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($service, $port) = ($1, $2); |
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} elsif ($service =~ /^\d+$/) { |
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($service, $port) = (undef, $service); |
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} else { |
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$port = (getservbyname $service, $proto)[2] |
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or Carp::croak "$service/$proto: service unknown"; |
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} |
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my @target = [$node, $port]; |
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# resolve a records / provide sockaddr structures |
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my $resolve = sub { |
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my @res; |
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my $cv = AnyEvent->condvar (cb => sub { |
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$cb->(map $_->[1], sort { $a->[0] <=> $b->[0] } @res) |
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}); |
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$cv->begin; |
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for my $idx (0 .. $#target) { |
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my ($node, $port) = @{ $target[$idx] }; |
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if (my $noden = AnyEvent::Socket::parse_ip ($node)) { |
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if (4 == length $noden && $family != 6) { |
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push @res, [$idx, [Socket::AF_INET, $type, $proton, |
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Socket::pack_sockaddr_in $port, $noden]] |
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} |
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if (16 == length $noden && $family != 4) { |
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push @res, [$idx, [Socket::AF_INET6, $type, $proton, |
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pack_sockaddr_in6 $port, $noden]] |
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} |
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} else { |
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# ipv4 |
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if ($family != 6) { |
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$cv->begin; |
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a $node, sub { |
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push @res, [$idx, [Socket::AF_INET, $type, $proton, |
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Socket::pack_sockaddr_in $port, AnyEvent::Socket::parse_ipv4 ($_)]] |
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for @_; |
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$cv->end; |
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}; |
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} |
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my $idx = $idx + 0.5; # prefer ipv4 for now |
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# ipv6 |
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if ($family != 4) { |
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$cv->begin; |
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aaaa $node, sub { |
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push @res, [$idx, [Socket::AF_INET6, $type, $proton, |
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pack_sockaddr_in6 $port, AnyEvent::Socket::parse_ipv6 ($_)]] |
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for @_; |
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$cv->end; |
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}; |
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} |
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} |
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} |
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$cv->end; |
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}; |
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# try srv records, if applicable |
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if (defined $service && !AnyEvent::Socket::parse_ip ($node)) { |
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srv $service, $proto, $node, sub { |
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my (@srv) = @_; |
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# no srv records, continue traditionally |
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@srv |
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or return &$resolve; |
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# only srv record has "." => abort |
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$srv[0][2] ne "." || $#srv |
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or return $cb->(); |
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# use srv records then |
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@target = map [$_->[3], $_->[2]], |
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grep $_->[3] ne ".", |
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@srv; |
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&$resolve; |
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}; |
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} else { |
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&$resolve; |
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} |
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} |
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############################################################################# |
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root |
1.15 |
=back |
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root |
1.13 |
=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS |
321 |
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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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1.11 |
support. By default, this is disabled (C<0>), but when set to C<1>, |
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AnyEvent::DNS will use EDNS0 in all requests. |
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1.1 |
=cut |
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1.11 |
our $EDNS0 = 0; # 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 = ( |
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a => 1, |
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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, |
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aaaa => 28, |
387 |
|
|
srv => 33, |
388 |
root |
1.5 |
opt => 41, |
389 |
|
|
spf => 99, |
390 |
|
|
tkey => 249, |
391 |
|
|
tsig => 250, |
392 |
|
|
ixfr => 251, |
393 |
root |
1.1 |
axfr => 252, |
394 |
|
|
mailb => 253, |
395 |
|
|
"*" => 255, |
396 |
|
|
); |
397 |
|
|
|
398 |
|
|
our %type_str = reverse %type_id; |
399 |
|
|
|
400 |
|
|
our %class_id = ( |
401 |
root |
1.5 |
in => 1, |
402 |
|
|
ch => 3, |
403 |
|
|
hs => 4, |
404 |
|
|
none => 254, |
405 |
|
|
"*" => 255, |
406 |
root |
1.1 |
); |
407 |
|
|
|
408 |
|
|
our %class_str = reverse %class_id; |
409 |
|
|
|
410 |
|
|
# names MUST have a trailing dot |
411 |
|
|
sub _enc_qname($) { |
412 |
|
|
pack "(C/a)*", (split /\./, shift), "" |
413 |
|
|
} |
414 |
|
|
|
415 |
|
|
sub _enc_qd() { |
416 |
|
|
(_enc_qname $_->[0]) . pack "nn", |
417 |
|
|
($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}), |
418 |
|
|
($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] || "in"}) |
419 |
|
|
} |
420 |
|
|
|
421 |
|
|
sub _enc_rr() { |
422 |
|
|
die "encoding of resource records is not supported"; |
423 |
|
|
} |
424 |
|
|
|
425 |
|
|
=item $pkt = AnyEvent::DNS::dns_pack $dns |
426 |
|
|
|
427 |
|
|
Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly |
428 |
|
|
recommended, then everything will be totally clear. Or maybe not. |
429 |
|
|
|
430 |
|
|
Resource records are not yet encodable. |
431 |
|
|
|
432 |
|
|
Examples: |
433 |
|
|
|
434 |
|
|
# very simple request, using lots of default values: |
435 |
|
|
{ rd => 1, qd => [ [ "host.domain", "a"] ] } |
436 |
|
|
|
437 |
|
|
# more complex example, showing how flags etc. are named: |
438 |
|
|
|
439 |
|
|
{ |
440 |
|
|
id => 10000, |
441 |
|
|
op => "query", |
442 |
|
|
rc => "nxdomain", |
443 |
|
|
|
444 |
|
|
# flags |
445 |
|
|
qr => 1, |
446 |
|
|
aa => 0, |
447 |
|
|
tc => 0, |
448 |
|
|
rd => 0, |
449 |
|
|
ra => 0, |
450 |
root |
1.5 |
ad => 0, |
451 |
|
|
cd => 0, |
452 |
root |
1.1 |
|
453 |
|
|
qd => [@rr], # query section |
454 |
|
|
an => [@rr], # answer section |
455 |
|
|
ns => [@rr], # authority section |
456 |
|
|
ar => [@rr], # additional records section |
457 |
|
|
} |
458 |
|
|
|
459 |
|
|
=cut |
460 |
|
|
|
461 |
|
|
sub dns_pack($) { |
462 |
|
|
my ($req) = @_; |
463 |
|
|
|
464 |
root |
1.7 |
pack "nn nnnn a* a* a* a* a*", |
465 |
root |
1.1 |
$req->{id}, |
466 |
|
|
|
467 |
|
|
! !$req->{qr} * 0x8000 |
468 |
|
|
+ $opcode_id{$req->{op}} * 0x0800 |
469 |
|
|
+ ! !$req->{aa} * 0x0400 |
470 |
|
|
+ ! !$req->{tc} * 0x0200 |
471 |
|
|
+ ! !$req->{rd} * 0x0100 |
472 |
|
|
+ ! !$req->{ra} * 0x0080 |
473 |
root |
1.5 |
+ ! !$req->{ad} * 0x0020 |
474 |
|
|
+ ! !$req->{cd} * 0x0010 |
475 |
root |
1.1 |
+ $rcode_id{$req->{rc}} * 0x0001, |
476 |
|
|
|
477 |
|
|
scalar @{ $req->{qd} || [] }, |
478 |
|
|
scalar @{ $req->{an} || [] }, |
479 |
|
|
scalar @{ $req->{ns} || [] }, |
480 |
root |
1.11 |
$EDNS0 + scalar @{ $req->{ar} || [] }, # include EDNS0 option here |
481 |
root |
1.1 |
|
482 |
|
|
(join "", map _enc_qd, @{ $req->{qd} || [] }), |
483 |
|
|
(join "", map _enc_rr, @{ $req->{an} || [] }), |
484 |
|
|
(join "", map _enc_rr, @{ $req->{ns} || [] }), |
485 |
root |
1.7 |
(join "", map _enc_rr, @{ $req->{ar} || [] }), |
486 |
|
|
|
487 |
root |
1.11 |
($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size |
488 |
root |
1.1 |
} |
489 |
|
|
|
490 |
|
|
our $ofs; |
491 |
|
|
our $pkt; |
492 |
|
|
|
493 |
|
|
# bitches |
494 |
|
|
sub _dec_qname { |
495 |
|
|
my @res; |
496 |
|
|
my $redir; |
497 |
|
|
my $ptr = $ofs; |
498 |
|
|
my $cnt; |
499 |
|
|
|
500 |
|
|
while () { |
501 |
|
|
return undef if ++$cnt >= 256; # to avoid DoS attacks |
502 |
|
|
|
503 |
|
|
my $len = ord substr $pkt, $ptr++, 1; |
504 |
|
|
|
505 |
|
|
if ($len & 0xc0) { |
506 |
|
|
$ptr++; |
507 |
|
|
$ofs = $ptr if $ptr > $ofs; |
508 |
|
|
$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff; |
509 |
|
|
} elsif ($len) { |
510 |
|
|
push @res, substr $pkt, $ptr, $len; |
511 |
|
|
$ptr += $len; |
512 |
|
|
} else { |
513 |
|
|
$ofs = $ptr if $ptr > $ofs; |
514 |
|
|
return join ".", @res; |
515 |
|
|
} |
516 |
|
|
} |
517 |
|
|
} |
518 |
|
|
|
519 |
|
|
sub _dec_qd { |
520 |
|
|
my $qname = _dec_qname; |
521 |
|
|
my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4; |
522 |
|
|
[$qname, $type_str{$qt} || $qt, $class_str{$qc} || $qc] |
523 |
|
|
} |
524 |
|
|
|
525 |
|
|
our %dec_rr = ( |
526 |
root |
1.17 |
1 => sub { join ".", unpack "C4" }, # a |
527 |
root |
1.1 |
2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns |
528 |
|
|
5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname |
529 |
|
|
6 => sub { |
530 |
|
|
local $ofs = $ofs - length; |
531 |
|
|
my $mname = _dec_qname; |
532 |
|
|
my $rname = _dec_qname; |
533 |
|
|
($mname, $rname, unpack "NNNNN", substr $pkt, $ofs) |
534 |
|
|
}, # soa |
535 |
root |
1.17 |
11 => sub { ((join ".", unpack "C4"), unpack "C a*", substr $_, 4) }, # wks |
536 |
root |
1.1 |
12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr |
537 |
root |
1.5 |
13 => sub { unpack "C/a C/a", $_ }, # hinfo |
538 |
root |
1.1 |
15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx |
539 |
root |
1.5 |
16 => sub { unpack "(C/a)*", $_ }, # txt |
540 |
root |
1.17 |
28 => sub { AnyEvent::Socket::format_ip ($_) }, # aaaa |
541 |
root |
1.1 |
33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv |
542 |
root |
1.5 |
99 => sub { unpack "(C/a)*", $_ }, # spf |
543 |
root |
1.1 |
); |
544 |
|
|
|
545 |
|
|
sub _dec_rr { |
546 |
|
|
my $qname = _dec_qname; |
547 |
|
|
|
548 |
|
|
my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10; |
549 |
|
|
local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen; |
550 |
|
|
|
551 |
|
|
[ |
552 |
|
|
$qname, |
553 |
|
|
$type_str{$rt} || $rt, |
554 |
|
|
$class_str{$rc} || $rc, |
555 |
|
|
($dec_rr{$rt} || sub { $_ })->(), |
556 |
|
|
] |
557 |
|
|
} |
558 |
|
|
|
559 |
|
|
=item $dns = AnyEvent::DNS::dns_unpack $pkt |
560 |
|
|
|
561 |
|
|
Unpacks a DNS packet into a perl data structure. |
562 |
|
|
|
563 |
|
|
Examples: |
564 |
|
|
|
565 |
root |
1.13 |
# an unsuccessful reply |
566 |
root |
1.1 |
{ |
567 |
|
|
'qd' => [ |
568 |
|
|
[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ] |
569 |
|
|
], |
570 |
|
|
'rc' => 'nxdomain', |
571 |
|
|
'ar' => [], |
572 |
|
|
'ns' => [ |
573 |
|
|
[ |
574 |
|
|
'uni-karlsruhe.de', |
575 |
|
|
'soa', |
576 |
|
|
'in', |
577 |
|
|
'netserv.rz.uni-karlsruhe.de', |
578 |
|
|
'hostmaster.rz.uni-karlsruhe.de', |
579 |
root |
1.13 |
2008052201, 10800, 1800, 2592000, 86400 |
580 |
root |
1.1 |
] |
581 |
|
|
], |
582 |
|
|
'tc' => '', |
583 |
|
|
'ra' => 1, |
584 |
|
|
'qr' => 1, |
585 |
|
|
'id' => 45915, |
586 |
|
|
'aa' => '', |
587 |
|
|
'an' => [], |
588 |
|
|
'rd' => 1, |
589 |
|
|
'op' => 'query' |
590 |
|
|
} |
591 |
|
|
|
592 |
|
|
# a successful reply |
593 |
|
|
|
594 |
|
|
{ |
595 |
|
|
'qd' => [ [ 'www.google.de', 'a', 'in' ] ], |
596 |
|
|
'rc' => 0, |
597 |
|
|
'ar' => [ |
598 |
|
|
[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ], |
599 |
|
|
[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ], |
600 |
|
|
[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ], |
601 |
|
|
], |
602 |
|
|
'ns' => [ |
603 |
|
|
[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ], |
604 |
|
|
[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ], |
605 |
|
|
], |
606 |
|
|
'tc' => '', |
607 |
|
|
'ra' => 1, |
608 |
|
|
'qr' => 1, |
609 |
|
|
'id' => 64265, |
610 |
|
|
'aa' => '', |
611 |
|
|
'an' => [ |
612 |
|
|
[ 'www.google.de', 'cname', 'in', 'www.google.com' ], |
613 |
|
|
[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ], |
614 |
|
|
[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ], |
615 |
|
|
[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ], |
616 |
|
|
], |
617 |
|
|
'rd' => 1, |
618 |
|
|
'op' => 0 |
619 |
|
|
} |
620 |
|
|
|
621 |
|
|
=cut |
622 |
|
|
|
623 |
|
|
sub dns_unpack($) { |
624 |
|
|
local $pkt = shift; |
625 |
|
|
my ($id, $flags, $qd, $an, $ns, $ar) |
626 |
|
|
= unpack "nn nnnn A*", $pkt; |
627 |
|
|
|
628 |
|
|
local $ofs = 6 * 2; |
629 |
|
|
|
630 |
|
|
{ |
631 |
|
|
id => $id, |
632 |
|
|
qr => ! ! ($flags & 0x8000), |
633 |
|
|
aa => ! ! ($flags & 0x0400), |
634 |
|
|
tc => ! ! ($flags & 0x0200), |
635 |
|
|
rd => ! ! ($flags & 0x0100), |
636 |
|
|
ra => ! ! ($flags & 0x0080), |
637 |
root |
1.5 |
ad => ! ! ($flags & 0x0020), |
638 |
|
|
cd => ! ! ($flags & 0x0010), |
639 |
root |
1.1 |
op => $opcode_str{($flags & 0x001e) >> 11}, |
640 |
|
|
rc => $rcode_str{($flags & 0x000f)}, |
641 |
|
|
|
642 |
|
|
qd => [map _dec_qd, 1 .. $qd], |
643 |
|
|
an => [map _dec_rr, 1 .. $an], |
644 |
|
|
ns => [map _dec_rr, 1 .. $ns], |
645 |
|
|
ar => [map _dec_rr, 1 .. $ar], |
646 |
|
|
} |
647 |
|
|
} |
648 |
|
|
|
649 |
|
|
############################################################################# |
650 |
|
|
|
651 |
|
|
=back |
652 |
|
|
|
653 |
|
|
=head2 THE AnyEvent::DNS RESOLVER CLASS |
654 |
|
|
|
655 |
root |
1.13 |
This is the class which does the actual protocol work. |
656 |
root |
1.1 |
|
657 |
|
|
=over 4 |
658 |
|
|
|
659 |
|
|
=cut |
660 |
|
|
|
661 |
|
|
use Carp (); |
662 |
|
|
use Scalar::Util (); |
663 |
|
|
use Socket (); |
664 |
|
|
|
665 |
|
|
our $NOW; |
666 |
|
|
|
667 |
root |
1.2 |
=item AnyEvent::DNS::resolver |
668 |
|
|
|
669 |
|
|
This function creates and returns a resolver that is ready to use and |
670 |
|
|
should mimic the default resolver for your system as good as possible. |
671 |
|
|
|
672 |
|
|
It only ever creates one resolver and returns this one on subsequent |
673 |
|
|
calls. |
674 |
|
|
|
675 |
|
|
Unless you have special needs, prefer this function over creating your own |
676 |
|
|
resolver object. |
677 |
|
|
|
678 |
|
|
=cut |
679 |
|
|
|
680 |
|
|
our $RESOLVER; |
681 |
|
|
|
682 |
|
|
sub resolver() { |
683 |
|
|
$RESOLVER || do { |
684 |
|
|
$RESOLVER = new AnyEvent::DNS; |
685 |
root |
1.14 |
$RESOLVER->os_config; |
686 |
root |
1.2 |
$RESOLVER |
687 |
|
|
} |
688 |
|
|
} |
689 |
|
|
|
690 |
root |
1.1 |
=item $resolver = new AnyEvent::DNS key => value... |
691 |
|
|
|
692 |
root |
1.6 |
Creates and returns a new resolver. |
693 |
root |
1.2 |
|
694 |
|
|
The following options are supported: |
695 |
root |
1.1 |
|
696 |
|
|
=over 4 |
697 |
|
|
|
698 |
|
|
=item server => [...] |
699 |
|
|
|
700 |
root |
1.13 |
A list of server addressses (default: C<v127.0.0.1>) in network format (4 |
701 |
root |
1.1 |
octets for IPv4, 16 octets for IPv6 - not yet supported). |
702 |
|
|
|
703 |
|
|
=item timeout => [...] |
704 |
|
|
|
705 |
|
|
A list of timeouts to use (also determines the number of retries). To make |
706 |
|
|
three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2, |
707 |
|
|
5, 5]>, which is also the default. |
708 |
|
|
|
709 |
|
|
=item search => [...] |
710 |
|
|
|
711 |
|
|
The default search list of suffixes to append to a domain name (default: none). |
712 |
|
|
|
713 |
root |
1.2 |
=item ndots => $integer |
714 |
root |
1.1 |
|
715 |
|
|
The number of dots (default: C<1>) that a name must have so that the resolver |
716 |
|
|
tries to resolve the name without any suffixes first. |
717 |
|
|
|
718 |
root |
1.2 |
=item max_outstanding => $integer |
719 |
root |
1.1 |
|
720 |
|
|
Most name servers do not handle many parallel requests very well. This option |
721 |
|
|
limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means |
722 |
|
|
if you request more than this many requests, then the additional requests will be queued |
723 |
|
|
until some other requests have been resolved. |
724 |
|
|
|
725 |
root |
1.13 |
=item reuse => $seconds |
726 |
|
|
|
727 |
|
|
The number of seconds (default: C<60>) that a query id cannot be re-used |
728 |
|
|
after a request. Since AnyEvent::DNS will only allocate up to 30000 ID's |
729 |
|
|
at the same time, the long-term maximum number of requests per second is |
730 |
|
|
C<30000 / $seconds> (and thus C<500> requests/s by default). |
731 |
|
|
|
732 |
root |
1.1 |
=back |
733 |
|
|
|
734 |
|
|
=cut |
735 |
|
|
|
736 |
|
|
sub new { |
737 |
|
|
my ($class, %arg) = @_; |
738 |
|
|
|
739 |
|
|
socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0 |
740 |
|
|
or Carp::croak "socket: $!"; |
741 |
|
|
|
742 |
|
|
AnyEvent::Util::fh_nonblocking $fh, 1; |
743 |
|
|
|
744 |
|
|
my $self = bless { |
745 |
|
|
server => [v127.0.0.1], |
746 |
|
|
timeout => [2, 5, 5], |
747 |
|
|
search => [], |
748 |
|
|
ndots => 1, |
749 |
|
|
max_outstanding => 10, |
750 |
root |
1.13 |
reuse => 60, # reuse id's after 5 minutes only, if possible |
751 |
root |
1.1 |
%arg, |
752 |
|
|
fh => $fh, |
753 |
|
|
reuse_q => [], |
754 |
|
|
}, $class; |
755 |
|
|
|
756 |
|
|
# search should default to gethostname's domain |
757 |
|
|
# but perl lacks a good posix module |
758 |
|
|
|
759 |
|
|
Scalar::Util::weaken (my $wself = $self); |
760 |
|
|
$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv }); |
761 |
|
|
|
762 |
|
|
$self->_compile; |
763 |
|
|
|
764 |
|
|
$self |
765 |
|
|
} |
766 |
|
|
|
767 |
|
|
=item $resolver->parse_resolv_conv ($string) |
768 |
|
|
|
769 |
|
|
Parses the given string a sif it were a F<resolv.conf> file. The following |
770 |
root |
1.14 |
directives are supported (but not neecssarily implemented). |
771 |
root |
1.1 |
|
772 |
|
|
C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>, |
773 |
|
|
C<options> (C<timeout>, C<attempts>, C<ndots>). |
774 |
|
|
|
775 |
|
|
Everything else is silently ignored. |
776 |
|
|
|
777 |
|
|
=cut |
778 |
|
|
|
779 |
|
|
sub parse_resolv_conf { |
780 |
|
|
my ($self, $resolvconf) = @_; |
781 |
|
|
|
782 |
|
|
$self->{server} = []; |
783 |
|
|
$self->{search} = []; |
784 |
|
|
|
785 |
|
|
my $attempts; |
786 |
|
|
|
787 |
|
|
for (split /\n/, $resolvconf) { |
788 |
|
|
if (/^\s*#/) { |
789 |
|
|
# comment |
790 |
|
|
} elsif (/^\s*nameserver\s+(\S+)\s*$/i) { |
791 |
|
|
my $ip = $1; |
792 |
|
|
if (AnyEvent::Util::dotted_quad $ip) { |
793 |
|
|
push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip; |
794 |
|
|
} else { |
795 |
|
|
warn "nameserver $ip invalid and ignored\n"; |
796 |
|
|
} |
797 |
|
|
} elsif (/^\s*domain\s+(\S*)\s+$/i) { |
798 |
|
|
$self->{search} = [$1]; |
799 |
|
|
} elsif (/^\s*search\s+(.*?)\s*$/i) { |
800 |
|
|
$self->{search} = [split /\s+/, $1]; |
801 |
|
|
} elsif (/^\s*sortlist\s+(.*?)\s*$/i) { |
802 |
|
|
# ignored, NYI |
803 |
|
|
} elsif (/^\s*options\s+(.*?)\s*$/i) { |
804 |
|
|
for (split /\s+/, $1) { |
805 |
|
|
if (/^timeout:(\d+)$/) { |
806 |
|
|
$self->{timeout} = [$1]; |
807 |
|
|
} elsif (/^attempts:(\d+)$/) { |
808 |
|
|
$attempts = $1; |
809 |
|
|
} elsif (/^ndots:(\d+)$/) { |
810 |
|
|
$self->{ndots} = $1; |
811 |
|
|
} else { |
812 |
|
|
# debug, rotate, no-check-names, inet6 |
813 |
|
|
} |
814 |
|
|
} |
815 |
|
|
} |
816 |
|
|
} |
817 |
|
|
|
818 |
|
|
$self->{timeout} = [($self->{timeout}[0]) x $attempts] |
819 |
|
|
if $attempts; |
820 |
|
|
|
821 |
|
|
$self->_compile; |
822 |
|
|
} |
823 |
|
|
|
824 |
root |
1.14 |
=item $resolver->os_config |
825 |
root |
1.1 |
|
826 |
root |
1.14 |
Tries so load and parse F</etc/resolv.conf> on portable opertaing systems. Tries various |
827 |
|
|
egregious hacks on windows to force the dns servers and searchlist out of the config. |
828 |
root |
1.1 |
|
829 |
|
|
=cut |
830 |
|
|
|
831 |
root |
1.14 |
sub os_config { |
832 |
root |
1.1 |
my ($self) = @_; |
833 |
|
|
|
834 |
root |
1.14 |
if ($^O =~ /mswin32|cygwin/i) { |
835 |
|
|
# yeah, it suxx... lets hope DNS is DNS in all locales |
836 |
|
|
|
837 |
|
|
if (open my $fh, "ipconfig /all |") { |
838 |
|
|
delete $self->{server}; |
839 |
|
|
delete $self->{search}; |
840 |
|
|
|
841 |
|
|
while (<$fh>) { |
842 |
|
|
# first DNS.* is suffix list |
843 |
|
|
if (/^\s*DNS/) { |
844 |
|
|
while (/\s+([[:alnum:].\-]+)\s*$/) { |
845 |
|
|
push @{ $self->{search} }, $1; |
846 |
|
|
$_ = <$fh>; |
847 |
|
|
} |
848 |
|
|
last; |
849 |
|
|
} |
850 |
|
|
} |
851 |
|
|
|
852 |
|
|
while (<$fh>) { |
853 |
|
|
# second DNS.* is server address list |
854 |
|
|
if (/^\s*DNS/) { |
855 |
|
|
while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) { |
856 |
|
|
my $ip = $1; |
857 |
|
|
push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip |
858 |
|
|
if AnyEvent::Util::dotted_quad $ip; |
859 |
|
|
$_ = <$fh>; |
860 |
|
|
} |
861 |
|
|
last; |
862 |
|
|
} |
863 |
|
|
} |
864 |
|
|
|
865 |
|
|
$self->_compile; |
866 |
|
|
} |
867 |
|
|
} else { |
868 |
|
|
# try resolv.conf everywhere |
869 |
root |
1.1 |
|
870 |
root |
1.14 |
if (open my $fh, "</etc/resolv.conf") { |
871 |
|
|
local $/; |
872 |
|
|
$self->parse_resolv_conf (<$fh>); |
873 |
|
|
} |
874 |
|
|
} |
875 |
root |
1.1 |
} |
876 |
|
|
|
877 |
|
|
sub _compile { |
878 |
|
|
my $self = shift; |
879 |
|
|
|
880 |
|
|
my @retry; |
881 |
|
|
|
882 |
|
|
for my $timeout (@{ $self->{timeout} }) { |
883 |
|
|
for my $server (@{ $self->{server} }) { |
884 |
|
|
push @retry, [$server, $timeout]; |
885 |
|
|
} |
886 |
|
|
} |
887 |
|
|
|
888 |
|
|
$self->{retry} = \@retry; |
889 |
|
|
} |
890 |
|
|
|
891 |
root |
1.6 |
sub _feed { |
892 |
|
|
my ($self, $res) = @_; |
893 |
|
|
|
894 |
|
|
$res = dns_unpack $res |
895 |
|
|
or return; |
896 |
|
|
|
897 |
|
|
my $id = $self->{id}{$res->{id}}; |
898 |
|
|
|
899 |
|
|
return unless ref $id; |
900 |
|
|
|
901 |
|
|
$NOW = time; |
902 |
|
|
$id->[1]->($res); |
903 |
|
|
} |
904 |
|
|
|
905 |
root |
1.1 |
sub _recv { |
906 |
|
|
my ($self) = @_; |
907 |
|
|
|
908 |
root |
1.9 |
while (my $peer = recv $self->{fh}, my $res, 4096, 0) { |
909 |
root |
1.1 |
my ($port, $host) = Socket::unpack_sockaddr_in $peer; |
910 |
|
|
|
911 |
|
|
return unless $port == 53 && grep $_ eq $host, @{ $self->{server} }; |
912 |
|
|
|
913 |
root |
1.6 |
$self->_feed ($res); |
914 |
root |
1.1 |
} |
915 |
|
|
} |
916 |
|
|
|
917 |
|
|
sub _exec { |
918 |
|
|
my ($self, $req, $retry) = @_; |
919 |
|
|
|
920 |
|
|
if (my $retry_cfg = $self->{retry}[$retry]) { |
921 |
|
|
my ($server, $timeout) = @$retry_cfg; |
922 |
|
|
|
923 |
|
|
$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub { |
924 |
|
|
$NOW = time; |
925 |
|
|
|
926 |
|
|
# timeout, try next |
927 |
|
|
$self->_exec ($req, $retry + 1); |
928 |
|
|
}), sub { |
929 |
|
|
my ($res) = @_; |
930 |
|
|
|
931 |
root |
1.6 |
if ($res->{tc}) { |
932 |
|
|
# success, but truncated, so use tcp |
933 |
root |
1.17 |
AnyEvent::Socket::tcp_connect ((Socket::inet_ntoa $server), 53, sub { |
934 |
root |
1.6 |
my ($fh) = @_ |
935 |
|
|
or return $self->_exec ($req, $retry + 1); |
936 |
|
|
|
937 |
|
|
my $handle = new AnyEvent::Handle |
938 |
|
|
fh => $fh, |
939 |
|
|
on_error => sub { |
940 |
|
|
# failure, try next |
941 |
|
|
$self->_exec ($req, $retry + 1); |
942 |
|
|
}; |
943 |
|
|
|
944 |
|
|
$handle->push_write (pack "n/a", $req->[0]); |
945 |
|
|
$handle->push_read_chunk (2, sub { |
946 |
|
|
$handle->unshift_read_chunk ((unpack "n", $_[1]), sub { |
947 |
|
|
$self->_feed ($_[1]); |
948 |
|
|
}); |
949 |
|
|
}); |
950 |
|
|
shutdown $fh, 1; |
951 |
|
|
|
952 |
root |
1.17 |
}, sub { $timeout }); |
953 |
root |
1.1 |
|
954 |
root |
1.6 |
} else { |
955 |
|
|
# success |
956 |
|
|
$self->{id}{$req->[2]} = 1; |
957 |
|
|
push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]]; |
958 |
|
|
--$self->{outstanding}; |
959 |
|
|
$self->_scheduler; |
960 |
|
|
|
961 |
|
|
$req->[1]->($res); |
962 |
|
|
} |
963 |
root |
1.1 |
}]; |
964 |
|
|
|
965 |
|
|
send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server; |
966 |
|
|
} else { |
967 |
|
|
# failure |
968 |
|
|
$self->{id}{$req->[2]} = 1; |
969 |
|
|
push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]]; |
970 |
|
|
--$self->{outstanding}; |
971 |
|
|
$self->_scheduler; |
972 |
|
|
|
973 |
|
|
$req->[1]->(); |
974 |
|
|
} |
975 |
|
|
} |
976 |
|
|
|
977 |
|
|
sub _scheduler { |
978 |
|
|
my ($self) = @_; |
979 |
|
|
|
980 |
|
|
$NOW = time; |
981 |
|
|
|
982 |
|
|
# first clear id reuse queue |
983 |
|
|
delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] } |
984 |
root |
1.13 |
while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW; |
985 |
root |
1.1 |
|
986 |
|
|
while ($self->{outstanding} < $self->{max_outstanding}) { |
987 |
root |
1.13 |
|
988 |
|
|
if (@{ $self->{reuse_q} } >= 30000) { |
989 |
|
|
# we ran out of ID's, wait a bit |
990 |
|
|
$self->{reuse_to} ||= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub { |
991 |
|
|
delete $self->{reuse_to}; |
992 |
|
|
$self->_scheduler; |
993 |
|
|
}); |
994 |
|
|
last; |
995 |
|
|
} |
996 |
|
|
|
997 |
root |
1.1 |
my $req = shift @{ $self->{queue} } |
998 |
|
|
or last; |
999 |
|
|
|
1000 |
|
|
while () { |
1001 |
|
|
$req->[2] = int rand 65536; |
1002 |
|
|
last unless exists $self->{id}{$req->[2]}; |
1003 |
|
|
} |
1004 |
|
|
|
1005 |
|
|
$self->{id}{$req->[2]} = 1; |
1006 |
|
|
substr $req->[0], 0, 2, pack "n", $req->[2]; |
1007 |
|
|
|
1008 |
|
|
++$self->{outstanding}; |
1009 |
|
|
$self->_exec ($req, 0); |
1010 |
|
|
} |
1011 |
|
|
} |
1012 |
|
|
|
1013 |
|
|
=item $resolver->request ($req, $cb->($res)) |
1014 |
|
|
|
1015 |
|
|
Sends a single request (a hash-ref formated as specified for |
1016 |
root |
1.3 |
C<dns_pack>) to the configured nameservers including |
1017 |
root |
1.1 |
retries. Calls the callback with the decoded response packet if a reply |
1018 |
|
|
was received, or no arguments on timeout. |
1019 |
|
|
|
1020 |
|
|
=cut |
1021 |
|
|
|
1022 |
|
|
sub request($$) { |
1023 |
|
|
my ($self, $req, $cb) = @_; |
1024 |
|
|
|
1025 |
root |
1.3 |
push @{ $self->{queue} }, [dns_pack $req, $cb]; |
1026 |
root |
1.1 |
$self->_scheduler; |
1027 |
|
|
} |
1028 |
|
|
|
1029 |
|
|
=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr)) |
1030 |
|
|
|
1031 |
|
|
Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a |
1032 |
|
|
qtype of "*" is supported and means "any"). |
1033 |
|
|
|
1034 |
|
|
The callback will be invoked with a list of matching result records or |
1035 |
|
|
none on any error or if the name could not be found. |
1036 |
|
|
|
1037 |
|
|
CNAME chains (although illegal) are followed up to a length of 8. |
1038 |
|
|
|
1039 |
root |
1.3 |
Note that this resolver is just a stub resolver: it requires a nameserver |
1040 |
|
|
supporting recursive queries, will not do any recursive queries itself and |
1041 |
|
|
is not secure when used against an untrusted name server. |
1042 |
|
|
|
1043 |
root |
1.1 |
The following options are supported: |
1044 |
|
|
|
1045 |
|
|
=over 4 |
1046 |
|
|
|
1047 |
|
|
=item search => [$suffix...] |
1048 |
|
|
|
1049 |
|
|
Use the given search list (which might be empty), by appending each one |
1050 |
|
|
in turn to the C<$qname>. If this option is missing then the configured |
1051 |
|
|
C<ndots> and C<search> define its value. If the C<$qname> ends in a dot, |
1052 |
root |
1.2 |
then the searchlist will be ignored. |
1053 |
root |
1.1 |
|
1054 |
|
|
=item accept => [$type...] |
1055 |
|
|
|
1056 |
|
|
Lists the acceptable result types: only result types in this set will be |
1057 |
|
|
accepted and returned. The default includes the C<$qtype> and nothing |
1058 |
|
|
else. |
1059 |
|
|
|
1060 |
|
|
=item class => "class" |
1061 |
|
|
|
1062 |
|
|
Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for |
1063 |
root |
1.2 |
hesiod are the only ones making sense). The default is "in", of course. |
1064 |
root |
1.1 |
|
1065 |
|
|
=back |
1066 |
|
|
|
1067 |
|
|
Examples: |
1068 |
|
|
|
1069 |
|
|
$res->resolve ("ruth.plan9.de", "a", sub { |
1070 |
|
|
warn Dumper [@_]; |
1071 |
|
|
}); |
1072 |
|
|
|
1073 |
|
|
[ |
1074 |
|
|
[ |
1075 |
|
|
'ruth.schmorp.de', |
1076 |
|
|
'a', |
1077 |
|
|
'in', |
1078 |
|
|
'129.13.162.95' |
1079 |
|
|
] |
1080 |
|
|
] |
1081 |
|
|
|
1082 |
|
|
$res->resolve ("test1.laendle", "*", |
1083 |
|
|
accept => ["a", "aaaa"], |
1084 |
|
|
sub { |
1085 |
|
|
warn Dumper [@_]; |
1086 |
|
|
} |
1087 |
|
|
); |
1088 |
|
|
|
1089 |
|
|
[ |
1090 |
|
|
[ |
1091 |
|
|
'test1.laendle', |
1092 |
|
|
'a', |
1093 |
|
|
'in', |
1094 |
|
|
'10.0.0.255' |
1095 |
|
|
], |
1096 |
|
|
[ |
1097 |
|
|
'test1.laendle', |
1098 |
|
|
'aaaa', |
1099 |
|
|
'in', |
1100 |
|
|
'3ffe:1900:4545:0002:0240:0000:0000:f7e1' |
1101 |
|
|
] |
1102 |
|
|
] |
1103 |
|
|
|
1104 |
|
|
=cut |
1105 |
|
|
|
1106 |
|
|
sub resolve($%) { |
1107 |
|
|
my $cb = pop; |
1108 |
|
|
my ($self, $qname, $qtype, %opt) = @_; |
1109 |
|
|
|
1110 |
|
|
my @search = $qname =~ s/\.$// |
1111 |
|
|
? "" |
1112 |
|
|
: $opt{search} |
1113 |
|
|
? @{ $opt{search} } |
1114 |
|
|
: ($qname =~ y/.//) >= $self->{ndots} |
1115 |
|
|
? ("", @{ $self->{search} }) |
1116 |
|
|
: (@{ $self->{search} }, ""); |
1117 |
|
|
|
1118 |
|
|
my $class = $opt{class} || "in"; |
1119 |
|
|
|
1120 |
|
|
my %atype = $opt{accept} |
1121 |
|
|
? map +($_ => 1), @{ $opt{accept} } |
1122 |
|
|
: ($qtype => 1); |
1123 |
|
|
|
1124 |
|
|
# advance in searchlist |
1125 |
|
|
my $do_search; $do_search = sub { |
1126 |
|
|
@search |
1127 |
|
|
or return $cb->(); |
1128 |
|
|
|
1129 |
root |
1.4 |
(my $name = lc "$qname." . shift @search) =~ s/\.$//; |
1130 |
root |
1.1 |
my $depth = 2; |
1131 |
|
|
|
1132 |
|
|
# advance in cname-chain |
1133 |
|
|
my $do_req; $do_req = sub { |
1134 |
|
|
$self->request ({ |
1135 |
|
|
rd => 1, |
1136 |
|
|
qd => [[$name, $qtype, $class]], |
1137 |
|
|
}, sub { |
1138 |
|
|
my ($res) = @_ |
1139 |
|
|
or return $do_search->(); |
1140 |
|
|
|
1141 |
|
|
my $cname; |
1142 |
|
|
|
1143 |
|
|
while () { |
1144 |
root |
1.2 |
# results found? |
1145 |
root |
1.4 |
my @rr = grep $name eq lc $_->[0] && ($atype{"*"} || $atype{$_->[1]}), @{ $res->{an} }; |
1146 |
root |
1.1 |
|
1147 |
|
|
return $cb->(@rr) |
1148 |
|
|
if @rr; |
1149 |
|
|
|
1150 |
|
|
# see if there is a cname we can follow |
1151 |
root |
1.4 |
my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} }; |
1152 |
root |
1.1 |
|
1153 |
|
|
if (@rr) { |
1154 |
|
|
$depth-- |
1155 |
|
|
or return $do_search->(); # cname chain too long |
1156 |
|
|
|
1157 |
|
|
$cname = 1; |
1158 |
|
|
$name = $rr[0][3]; |
1159 |
|
|
|
1160 |
|
|
} elsif ($cname) { |
1161 |
|
|
# follow the cname |
1162 |
|
|
return $do_req->(); |
1163 |
|
|
|
1164 |
|
|
} else { |
1165 |
root |
1.2 |
# no, not found anything |
1166 |
root |
1.1 |
return $do_search->(); |
1167 |
|
|
} |
1168 |
|
|
} |
1169 |
|
|
}); |
1170 |
|
|
}; |
1171 |
|
|
|
1172 |
|
|
$do_req->(); |
1173 |
|
|
}; |
1174 |
|
|
|
1175 |
|
|
$do_search->(); |
1176 |
|
|
} |
1177 |
|
|
|
1178 |
root |
1.17 |
use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end |
1179 |
|
|
|
1180 |
root |
1.1 |
1; |
1181 |
|
|
|
1182 |
|
|
=back |
1183 |
|
|
|
1184 |
|
|
=head1 AUTHOR |
1185 |
|
|
|
1186 |
|
|
Marc Lehmann <schmorp@schmorp.de> |
1187 |
|
|
http://home.schmorp.de/ |
1188 |
|
|
|
1189 |
|
|
=cut |
1190 |
|
|
|