package Net::DNS;
use strict;
BEGIN {
eval { require bytes; }
}
use vars qw(
$HAVE_XS
$VERSION
$SVNVERSION
$DNSSEC
$DN_EXPAND_ESCAPES
@ISA
@EXPORT
@EXPORT_OK
%typesbyname
%typesbyval
%qtypesbyname
%qtypesbyval
%metatypesbyname
%metatypesbyval
%classesbyname
%classesbyval
%opcodesbyname
%opcodesbyval
%rcodesbyname
%rcodesbyval
);
BEGIN {
require DynaLoader;
require Exporter;
@ISA = qw(Exporter DynaLoader);
$VERSION = '0.63';
$SVNVERSION = (qw$LastChangedRevision: 710 $)[1];
$HAVE_XS = eval {
local $SIG{'__DIE__'} = 'DEFAULT';
__PACKAGE__->bootstrap(); 1
} ? 1 : 0;
}
BEGIN {
$DNSSEC = eval {
local $SIG{'__DIE__'} = 'DEFAULT';
require Net::DNS::SEC;
1
} ? 1 : 0;
}
use Net::DNS::Resolver;
use Net::DNS::Packet;
use Net::DNS::Update;
use Net::DNS::Header;
use Net::DNS::Question;
use Net::DNS::RR; use Carp;
@EXPORT = qw(mx yxrrset nxrrset yxdomain nxdomain rr_add rr_del);
@EXPORT_OK= qw(name2labels wire2presentation rrsort);
%typesbyname = (
'SIGZERO' => 0, 'A' => 1, 'NS' => 2, 'MD' => 3, 'MF' => 4, 'CNAME' => 5, 'SOA' => 6, 'MB' => 7, 'MG' => 8, 'MR' => 9, 'NULL' => 10, 'WKS' => 11, 'PTR' => 12, 'HINFO' => 13, 'MINFO' => 14, 'MX' => 15, 'TXT' => 16, 'RP' => 17, 'AFSDB' => 18, 'X25' => 19, 'ISDN' => 20, 'RT' => 21, 'NSAP' => 22, 'NSAP_PTR' => 23, 'SIG' => 24, 'KEY' => 25, 'PX' => 26, 'GPOS' => 27, 'AAAA' => 28, 'LOC' => 29, 'NXT' => 30, 'EID' => 31, 'NIMLOC' => 32, 'SRV' => 33, 'ATMA' => 34, 'NAPTR' => 35, 'KX' => 36, 'CERT' => 37, 'DNAME' => 39, 'OPT' => 41, 'DS' => 43, 'SSHFP' => 44, 'IPSECKEY' => 45, 'RRSIG' => 46, 'NSEC' => 47, 'DNSKEY' => 48, 'NSEC3' => 50, 'NSEC3PARAM' => 51,
'SPF' => 99, 'UINFO' => 100, 'UID' => 101, 'GID' => 102, 'UNSPEC' => 103, 'TKEY' => 249, 'TSIG' => 250, 'IXFR' => 251, 'AXFR' => 252, 'MAILB' => 253, 'MAILA' => 254, 'ANY' => 255, 'DLV' => 32769 );
%typesbyval = reverse %typesbyname;
sub typesbyname {
my $name = uc shift;
return $typesbyname{$name} if defined $typesbyname{$name};
confess "Net::DNS::typesbyname() argument ($name) is not TYPE###" unless
$name =~ m/^\s*TYPE(\d+)\s*$/o;
my $val = $1;
confess 'Net::DNS::typesbyname() argument larger than ' . 0xffff if $val > 0xffff;
return $val;
}
sub typesbyval {
my $val = shift;
confess "Net::DNS::typesbyval() argument is not defined" unless defined $val;
confess "Net::DNS::typesbyval() argument ($val) is not numeric" unless
$val =~ s/^\s*0*(\d+)\s*$/$1/o;
return $typesbyval{$val} if $typesbyval{$val};
confess 'Net::DNS::typesbyval() argument larger than '. 0xffff if
$val > 0xffff;
return "TYPE$val";
}
%classesbyname = (
'IN' => 1, 'CH' => 3, 'HS' => 4, 'NONE' => 254, 'ANY' => 255, );
%classesbyval = reverse %classesbyname;
sub classesbyname {
my $name = uc shift;
return $classesbyname{$name} if $classesbyname{$name};
confess "Net::DNS::classesbyval() argument is not CLASS### ($name)" unless
$name =~ m/^\s*CLASS(\d+)\s*$/o;
my $val = $1;
confess 'Net::DNS::classesbyval() argument larger than '. 0xffff if $val > 0xffff;
return $val;
}
sub classesbyval {
my $val = shift;
confess "Net::DNS::classesbyname() argument is not numeric ($val)" unless
$val =~ s/^\s*0*([0-9]+)\s*$/$1/o;
return $classesbyval{$val} if $classesbyval{$val};
confess 'Net::DNS::classesbyname() argument larger than ' . 0xffff if $val > 0xffff;
return "CLASS$val";
}
%qtypesbyname = (
'IXFR' => 251, 'AXFR' => 252, 'MAILB' => 253, 'MAILA' => 254, 'ANY' => 255, );
%qtypesbyval = reverse %qtypesbyname;
%metatypesbyname = (
'TKEY' => 249, 'TSIG' => 250, 'OPT' => 41, );
%metatypesbyval = reverse %metatypesbyname;
%opcodesbyname = (
'QUERY' => 0, 'IQUERY' => 1, 'STATUS' => 2, 'NS_NOTIFY_OP' => 4, 'UPDATE' => 5, );
%opcodesbyval = reverse %opcodesbyname;
%rcodesbyname = (
'NOERROR' => 0, 'FORMERR' => 1, 'SERVFAIL' => 2, 'NXDOMAIN' => 3, 'NOTIMP' => 4, 'REFUSED' => 5, 'YXDOMAIN' => 6, 'YXRRSET' => 7, 'NXRRSET' => 8, 'NOTAUTH' => 9, 'NOTZONE' => 10, );
%rcodesbyval = reverse %rcodesbyname;
sub version { $VERSION; }
sub PACKETSZ () { 512; }
sub HFIXEDSZ () { 12; }
sub QFIXEDSZ () { 4; }
sub RRFIXEDSZ () { 10; }
sub INT32SZ () { 4; }
sub INT16SZ () { 2; }
sub mx {
my $res = ref $_[0] ? shift : Net::DNS::Resolver->new;
my ($name, $class) = @_;
$class ||= 'IN';
my $ans = $res->query($name, 'MX', $class) || return;
my @ret = sort { $a->preference <=> $b->preference }
grep { $_->type eq 'MX'} $ans->answer;
return @ret;
}
sub yxrrset {
return Net::DNS::RR->new_from_string(shift, 'yxrrset');
}
sub nxrrset {
return Net::DNS::RR->new_from_string(shift, 'nxrrset');
}
sub yxdomain {
return Net::DNS::RR->new_from_string(shift, 'yxdomain');
}
sub nxdomain {
return Net::DNS::RR->new_from_string(shift, 'nxdomain');
}
sub rr_add {
return Net::DNS::RR->new_from_string(shift, 'rr_add');
}
sub rr_del {
return Net::DNS::RR->new_from_string(shift, 'rr_del');
}
sub name2labels {
my $dname=shift;
my @names;
my $j=0;
while ($dname){
($names[$j],$dname)=presentation2wire($dname);
$j++;
}
return @names;
}
sub wire2presentation {
my $wire=shift;
my $presentation="";
my $length=length($wire);
my $i=0;
while ($i < $length ){
my $char=unpack("x".$i."C1",$wire);
if ( $char < 33 || $char > 126 ){
$presentation.= sprintf ("\\%03u" ,$char);
}elsif ( $char == ord( "\"" )) {
$presentation.= "\\\"";
}elsif ( $char == ord( "\$" )) {
$presentation.= "\\\$";
}elsif ( $char == ord( "(" )) {
$presentation.= "\\(";
}elsif ( $char == ord( ")" )) {
$presentation.= "\\)";
}elsif ( $char == ord( ";" )) {
$presentation.= "\\;";
}elsif ( $char == ord( "@" )) {
$presentation.= "\\@";
}elsif ( $char == ord( "\\" )) {
$presentation.= "\\\\" ;
}elsif ( $char==ord (".") ){
$presentation.= "\\." ;
}else{
$presentation.=chr($char) ;
}
$i++;
}
return $presentation;
}
sub presentation2wire {
my $presentation=shift;
my $wire="";
my $length=length($presentation);
my $i=0;
while ($i < $length ){
my $char=unpack("x".$i."C1",$presentation);
if ( $char == ord ('.')){
return ($wire,substr($presentation,$i+1));
}
if ( $char == ord ('\\')){
pos($presentation)=$i+1;
if ($presentation=~/\G(\d\d\d)/){
$wire.=pack("C",$1);
$i+=3;
}elsif($presentation=~/\Gx([0..9a..fA..F][0..9a..fA..F])/){
$wire.=pack("H*",$1);
$i+=3;
}elsif($presentation=~/\G\./){
$wire.="\.";
$i+=1;
}elsif($presentation=~/\G@/){
$wire.="@";
$i+=1;
}elsif($presentation=~/\G\(/){
$wire.="(";
$i+=1;
}elsif($presentation=~/\G\)/){
$wire.=")";
$i+=1;
}elsif($presentation=~/\G\\/){
$wire.="\\";
$i+=1;
}
}else{
$wire .= pack("C",$char);
}
$i++;
}
return $wire;
}
sub rrsort {
my ($rrtype,$attribute,@rr_array)=@_;
unless (exists($Net::DNS::typesbyname{uc($rrtype)})){
return();
}
unless (defined($attribute)){
return();
}
if( ref($attribute)=~/^Net::DNS::RR::.*/){
push @rr_array,$attribute;
undef($attribute);
}
my @extracted_rr;
foreach my $rr (@rr_array){
push( @extracted_rr, $rr )if (uc($rr->type) eq uc($rrtype));
}
return () unless @extracted_rr;
my $func=("Net::DNS::RR::".$rrtype)->get_rrsort_func($attribute);
my @sorted=sort $func @extracted_rr;
return @sorted;
}
1;
__END__
=head1 NAME
Net::DNS - Perl interface to the DNS resolver
=head1 SYNOPSIS
C<use Net::DNS;>
=head1 DESCRIPTION
Net::DNS is a collection of Perl modules that act as a Domain
Name System (DNS) resolver. It allows the programmer to perform
DNS queries that are beyond the capabilities of C<gethostbyname>
and C<gethostbyaddr>.
The programmer should be somewhat familiar with the format of
a DNS packet and its various sections. See RFC 1035 or
I<DNS and BIND> (Albitz & Liu) for details.
=head2 Resolver Objects
A resolver object is an instance of the
L<Net::DNS::Resolver|Net::DNS::Resolver> class. A program can have
multiple resolver objects, each maintaining its own state information
such as the nameservers to be queried, whether recursion is desired,
etc.
=head2 Packet Objects
L<Net::DNS::Resolver|Net::DNS::Resolver> queries return
L<Net::DNS::Packet|Net::DNS::Packet> objects. Packet objects have five
sections:
=over 3
=item *
The header section, a L<Net::DNS::Header|Net::DNS::Header> object.
=item *
The question section, a list of L<Net::DNS::Question|Net::DNS::Question>
objects.
=item *
The answer section, a list of L<Net::DNS::RR|Net::DNS::RR> objects.
=item *
The authority section, a list of L<Net::DNS::RR|Net::DNS::RR> objects.
=item *
The additional section, a list of L<Net::DNS::RR|Net::DNS::RR> objects.
=back
=head2 Update Objects
The L<Net::DNS::Update|Net::DNS::Update> package is a subclass of
L<Net::DNS::Packet|Net::DNS::Packet> for creating packet objects to be
used in dynamic updates.
=head2 Header Objects
L<Net::DNS::Header|Net::DNS::Header> objects represent the header
section of a DNS packet.
=head2 Question Objects
L<Net::DNS::Question|Net::DNS::Question> objects represent the question
section of a DNS packet.
=head2 RR Objects
L<Net::DNS::RR|Net::DNS::RR> is the base class for DNS resource record
(RR) objects in the answer, authority, and additional sections of a DNS
packet.
Don't assume that RR objects will be of the type you requested -- always
check an RR object's type before calling any of its methods.
=head1 METHODS
See the manual pages listed above for other class-specific methods.
=head2 version
print Net::DNS->version, "\n";
Returns the version of Net::DNS.
=head2 mx
# Use a default resolver -- can't get an error string this way.
use Net::DNS;
my @mx = mx("example.com");
# Use your own resolver object.
use Net::DNS;
my $res = Net::DNS::Resolver->new;
my @mx = mx($res, "example.com");
Returns a list of L<Net::DNS::RR::MX|Net::DNS::RR::MX> objects
representing the MX records for the specified name; the list will be
sorted by preference. Returns an empty list if the query failed or no MX
records were found.
This method does not look up A records -- it only performs MX queries.
See L</EXAMPLES> for a more complete example.
=head2 yxrrset
Use this method to add an "RRset exists" prerequisite to a dynamic
update packet. There are two forms, value-independent and
value-dependent:
# RRset exists (value-independent)
$update->push(pre => yxrrset("host.example.com A"));
Meaning: At least one RR with the specified name and type must
exist.
# RRset exists (value-dependent)
$packet->push(pre => yxrrset("host.example.com A 10.1.2.3"));
Meaning: At least one RR with the specified name and type must
exist and must have matching data.
Returns a C<Net::DNS::RR> object or C<undef> if the object couldn't
be created.
=head2 nxrrset
Use this method to add an "RRset does not exist" prerequisite to
a dynamic update packet.
$packet->push(pre => nxrrset("host.example.com A"));
Meaning: No RRs with the specified name and type can exist.
Returns a C<Net::DNS::RR> object or C<undef> if the object couldn't
be created.
=head2 yxdomain
Use this method to add a "name is in use" prerequisite to a dynamic
update packet.
$packet->push(pre => yxdomain("host.example.com"));
Meaning: At least one RR with the specified name must exist.
Returns a C<Net::DNS::RR> object or C<undef> if the object couldn't
be created.
=head2 nxdomain
Use this method to add a "name is not in use" prerequisite to a
dynamic update packet.
$packet->push(pre => nxdomain("host.example.com"));
Meaning: No RR with the specified name can exist.
Returns a C<Net::DNS::RR> object or C<undef> if the object couldn't
be created.
=head2 rr_add
Use this method to add RRs to a zone.
$packet->push(update => rr_add("host.example.com A 10.1.2.3"));
Meaning: Add this RR to the zone.
RR objects created by this method should be added to the "update"
section of a dynamic update packet. The TTL defaults to 86400
seconds (24 hours) if not specified.
Returns a C<Net::DNS::RR> object or C<undef> if the object couldn't
be created.
=head2 rr_del
Use this method to delete RRs from a zone. There are three forms:
delete an RRset, delete all RRsets, and delete an RR.
# Delete an RRset.
$packet->push(update => rr_del("host.example.com A"));
Meaning: Delete all RRs having the specified name and type.
# Delete all RRsets.
$packet->push(update => rr_del("host.example.com"));
Meaning: Delete all RRs having the specified name.
# Delete an RR.
$packet->push(update => rr_del("host.example.com A 10.1.2.3"));
Meaning: Delete all RRs having the specified name, type, and data.
RR objects created by this method should be added to the "update"
section of a dynamic update packet.
Returns a C<Net::DNS::RR> object or C<undef> if the object couldn't
be created.
=head2 Sorting of RR arrays
As of version 0.55 there is functionality to help you sort RR
arrays. 'rrsort()' is the function that is available to do the
sorting. In most cases rrsort will give you the answer that you
want but you can specify your own sorting method by using the
Net::DNS::RR::FOO->set_rrsort_func() class method. See L<Net::DNS::RR>
for details.
=head3 rrsort()
use Net::DNS qw(rrsort);
my @prioritysorted=rrsort("SRV","priority",@rr_array);
rrsort() selects all RRs from the input array that are of the type
that are defined in the first argument. Those RRs are sorted based on
the attribute that is specified as second argument.
There are a number of RRs for which the sorting function is
specifically defined for certain attributes. If such sorting function
is defined in the code (it can be set or overwritten using the
set_rrsort_func() class method) that function is used.
For instance:
my @prioritysorted=rrsort("SRV","priority",@rr_array);
returns the SRV records sorted from lowest to heighest priority and
for equal priorities from heighes to lowes weight.
If the function does not exist then a numerical sort on the attribute
value is performed.
my @portsorted=rrsort("SRV","port",@rr_array);
If the attribute does not exist for a certain RR than the RRs are
sorted on string comparrisson of the rdata.
If the attribute is not defined than either the default_sort function
will be defined or "Canonical sorting" (as defined by DNSSEC) will be
used.
rrsort() returns a sorted array with only elements of the specified
RR type or undef.
rrsort() returns undef when arguments are incorrect.
=head1 EXAMPLES
The following examples show how to use the C<Net::DNS> modules.
See the other manual pages and the demo scripts included with the
source code for additional examples.
See the C<Net::DNS::Update> manual page for an example of performing
dynamic updates.
=head2 Look up a host's addresses.
use Net::DNS;
my $res = Net::DNS::Resolver->new;
my $query = $res->search("host.example.com");
if ($query) {
foreach my $rr ($query->answer) {
next unless $rr->type eq "A";
print $rr->address, "\n";
}
} else {
warn "query failed: ", $res->errorstring, "\n";
}
=head2 Find the nameservers for a domain.
use Net::DNS;
my $res = Net::DNS::Resolver->new;
my $query = $res->query("example.com", "NS");
if ($query) {
foreach $rr (grep { $_->type eq 'NS' } $query->answer) {
print $rr->nsdname, "\n";
}
}
else {
warn "query failed: ", $res->errorstring, "\n";
}
=head2 Find the MX records for a domain.
use Net::DNS;
my $name = "example.com";
my $res = Net::DNS::Resolver->new;
my @mx = mx($res, $name);
if (@mx) {
foreach $rr (@mx) {
print $rr->preference, " ", $rr->exchange, "\n";
}
} else {
warn "Can't find MX records for $name: ", $res->errorstring, "\n";
}
=head2 Print a domain's SOA record in zone file format.
use Net::DNS;
my $res = Net::DNS::Resolver->new;
my $query = $res->query("example.com", "SOA");
if ($query) {
($query->answer)[0]->print;
} else {
print "query failed: ", $res->errorstring, "\n";
}
=head2 Perform a zone transfer and print all the records.
use Net::DNS;
my $res = Net::DNS::Resolver->new;
$res->nameservers("ns.example.com");
my @zone = $res->axfr("example.com");
foreach $rr (@zone) {
$rr->print;
}
=head2 Perform a background query and do some other work while waiting
for the answer.
use Net::DNS;
my $res = Net::DNS::Resolver->new;
my $socket = $res->bgsend("host.example.com");
until ($res->bgisready($socket)) {
# do some work here while waiting for the answer
# ...and some more here
}
my $packet = $res->bgread($socket);
$packet->print;
=head2 Send a background query and use select to determine when the answer
has arrived.
use Net::DNS;
use IO::Select;
my $timeout = 5;
my $res = Net::DNS::Resolver->new;
my $bgsock = $res->bgsend("host.example.com");
my $sel = IO::Select->new($bgsock);
# Add more sockets to $sel if desired.
my @ready = $sel->can_read($timeout);
if (@ready) {
foreach my $sock (@ready) {
if ($sock == $bgsock) {
my $packet = $res->bgread($bgsock);
$packet->print;
$bgsock = undef;
}
# Check for the other sockets.
$sel->remove($sock);
$sock = undef;
}
} else {
warn "timed out after $timeout seconds\n";
}
=head1 BUGS
C<Net::DNS> is slow.
For other items to be fixed, please see the TODO file included with
the source distribution.
=head1 COPYRIGHT
Copyright (c) 1997-2002 Michael Fuhr.
Portions Copyright (c) 2002-2004 Chris Reinhardt.
Portions Copyright (c) 2005 Olaf Kolkman (RIPE NCC)
Portions Copyright (c) 2006 Olaf Kolkman (NLnet Labs)
All rights reserved. This program is free software; you may redistribute
it and/or modify it under the same terms as Perl itself.
=head1 AUTHOR INFORMATION
Net::DNS is currently maintained at NLnet Labs (www.nlnetlabs.nl) by:
Olaf Kolkman
olaf@net-dns.org
Between 2002 and 2004 Net::DNS was maintained by:
Chris Reinhardt
Net::DNS was created by:
Michael Fuhr
mike@fuhr.org
For more information see:
http://www.net-dns.org/
Stay tuned and syncicate:
http://www.net-dns.org/blog/
=head1 SEE ALSO
L<perl(1)>, L<Net::DNS::Resolver>, L<Net::DNS::Packet>, L<Net::DNS::Update>,
L<Net::DNS::Header>, L<Net::DNS::Question>, L<Net::DNS::RR>, RFC 1035,
I<DNS and BIND> by Paul Albitz & Cricket Liu
=cut