[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent/DNS.pm

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.17 by root, Fri May 23 20:21:50 2008 UTC vs.
Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
		8
		9	my $cv = AnyEvent->condvar;
		10	AnyEvent::DNS::a "www.google.de", $cv;
		11	# ... later
		12	my @addrs = $cv->recv;
8		13
9	=head1 DESCRIPTION	14	=head1 DESCRIPTION
10		15
11	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
12	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
13		18
14	The stub resolver supports DNS over UDP, optional EDNS0 support for up to	19	The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional
15	4kiB datagrams and automatically falls back to virtual circuit mode for	20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
16	large responses.	21	virtual circuit mode for large responses.
17		22
18	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
19		24
20	=over 4	25	=over 4
21		26
…		…
24	package AnyEvent::DNS;	29	package AnyEvent::DNS;
25		30
26	no warnings;	31	no warnings;
27	use strict;	32	use strict;
28		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
		36	use AnyEvent ();
29	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
30		39
31	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.45;
32		41
33	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
34
35	Tries to resolve the given nodename and service name into sockaddr
36	structures usable to connect to this node and service in a
37	protocol-independent way. It works similarly to the getaddrinfo posix
38	function.
39
40	Example:
41
42	AnyEvent::DNS::addr "google.com", "http", AF_UNSPEC, SOCK_STREAM, sub { ... };
43		43
44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
45		45
46	Tries to resolve the given domain to IPv4 address(es).	46	Tries to resolve the given domain to IPv4 address(es).
47		47
…		…
65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
66		66
67	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
68	of service records.	68	of service records.
69		69
70	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
71	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
72		72
73	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
74	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
75		75
76	Example:	76	Example:
77		77
78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
80		80
81	=item AnyEvent::DNS::ptr $ipv4_or_6, $cb->(@hostnames)	81	=item AnyEvent::DNS::ptr $domain, $cb->(@hostnames)
		82
		83	Tries to make a PTR lookup on the given domain. See C<reverse_lookup>
		84	and C<reverse_verify> if you want to resolve an IP address to a hostname
		85	instead.
		86
		87	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
		88
		89	Tries to resolve the given domain and passes all resource records found to
		90	the callback.
		91
		92	=item AnyEvent::DNS::reverse_lookup $ipv4_or_6, $cb->(@hostnames)
82		93
83	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)	94	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)
84	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
		97
		98	=item AnyEvent::DNS::reverse_verify $ipv4_or_6, $cb->(@hostnames)
		99
		100	The same as C<reverse_lookup>, but does forward-lookups to verify that
		101	the resolved hostnames indeed point to the address, which makes spoofing
		102	harder.
		103
		104	If you want to resolve an address into a hostname, this is the preferred
		105	method: The DNS records could still change, but at least this function
		106	verified that the hostname, at one point in the past, pointed at the IP
		107	address you originally resolved.
85		108
86	Example:	109	Example:
87		110
88	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
89	# => f.root-servers.net	112	# => f.root-servers.net
90		113
91	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
92
93	Tries to resolve the given domain and passes all resource records found to
94	the callback.
95
96	=cut	114	=cut
		115
		116	sub MAX_PKT() { 4096 } # max packet size we advertise and accept
		117
		118	sub DOMAIN_PORT() { 53 } # if this changes drop me a note
97		119
98	sub resolver;	120	sub resolver;
99		121
100	sub a($$) {	122	sub a($$) {
101	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
140	sub srv($$$$) {	162	sub srv($$$$) {
141	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
142		164
143	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
144	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
145	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
146	});	194	});
147	}	195	}
148		196
149	sub ptr($$) {	197	sub ptr($$) {
		198	my ($domain, $cb) = @_;
		199
		200	resolver->resolve ($domain => "ptr", sub {
		201	$cb->(map $_->[3], @_);
		202	});
		203	}
		204
		205	sub any($$) {
		206	my ($domain, $cb) = @_;
		207
		208	resolver->resolve ($domain => "*", $cb);
		209	}
		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
150	my ($ip, $cb) = @_;	239	my ($ip, $cb) = @_;
151		240
152	$ip = AnyEvent::Socket::parse_ip ($ip)	241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
153	or return $cb->();	242	or return $cb->();
154
155	if (4 == length $ip) {
156	$ip = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
157	} else {
158	$ip = join ".", (reverse split //, unpack "H*", $ip), "ip6.arpa.";
159	}
160		243
161	resolver->resolve ($ip => "ptr", sub {	244	resolver->resolve ($ip => "ptr", sub {
162	$cb->(map $_->[3], @_);	245	$cb->(map $_->[3], @_);
163	});	246	});
164	}	247	}
165		248
166	sub any($$) {	249	sub reverse_verify($$) {
167	my ($domain, $cb) = @_;	250	my ($ip, $cb) = @_;
		251
		252	my $ipn = AnyEvent::Socket::parse_address ($ip)
		253	or return $cb->();
168		254
169	resolver->resolve ($domain => "*", $cb);	255	my $af = AnyEvent::Socket::address_family ($ipn);
		256
		257	my @res;
		258	my $cnt;
		259
		260	my $ptr = _munge_ptr $ipn
		261	or return $cb->();
		262
		263	$ip = AnyEvent::Socket::format_address ($ipn); # normalise into the same form
		264
		265	ptr $ptr, sub {
		266	for my $name (@_) {
		267	++$cnt;
		268
		269	# () around AF_INET to work around bug in 5.8
		270	resolver->resolve ("$name." => ($af == (AF_INET) ? "a" : "aaaa"), sub {
		271	for (@_) {
		272	push @res, $name
		273	if $_->[3] eq $ip;
		274	}
		275	$cb->(@res) unless --$cnt;
		276	});
		277	}
		278
		279	$cb->() unless $cnt;
		280	};
170	}	281	}
		282
		283	#################################################################################
171		284
172	=back	285	=back
173		286
174	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
175		288
176	=over 4	289	=over 4
177		290
178	=item $AnyEvent::DNS::EDNS0	291	=item $AnyEvent::DNS::EDNS0
179		292
180	This variable decides whether dns_pack automatically enables EDNS0	293	This variable decides whether dns_pack automatically enables EDNS0
181	support. By default, this is disabled (C<0>), but when set to C<1>,	294	support. By default, this is disabled (C<0>), unless overridden by
182	AnyEvent::DNS will use EDNS0 in all requests.	295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
		296	EDNS0 in all requests.
183		297
184	=cut	298	=cut
185		299
186	our $EDNS0 = 0; # set to 1 to enable (partial) edns0	300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0}*1; # set to 1 to enable (partial) edns0
187		301
188	our %opcode_id = (	302	our %opcode_id = (
189	query => 0,	303	query => 0,
190	iquery => 1,	304	iquery => 1,
191	status => 2,	305	status => 2,
…		…
237	minfo => 14,	351	minfo => 14,
238	mx => 15,	352	mx => 15,
239	txt => 16,	353	txt => 16,
240	aaaa => 28,	354	aaaa => 28,
241	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
		357	dname => 39, # rfc2672
242	opt => 41,	358	opt => 41,
243	spf => 99,	359	spf => 99,
244	tkey => 249,	360	tkey => 249,
245	tsig => 250,	361	tsig => 250,
246	ixfr => 251,	362	ixfr => 251,
…		…
259	"*" => 255,	375	"*" => 255,
260	);	376	);
261		377
262	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
263		379
264	# names MUST have a trailing dot
265	sub _enc_qname($) {	380	sub _enc_name($) {
266	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
267	}	382	}
268		383
269	sub _enc_qd() {	384	sub _enc_qd() {
270	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
271	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
272	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
273	}	388	}
274		389
275	sub _enc_rr() {	390	sub _enc_rr() {
276	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
277	}	392	}
278		393
279	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
280		395
281	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	396	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
282	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
283		398
284	Resource records are not yet encodable.	399	Resource records are not yet encodable.
285		400
286	Examples:	401	Examples:
287		402
288	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
289	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
290		405
291	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
292		407
293	{	408	{
294	id => 10000,	409	id => 10000,
295	op => "query",	410	op => "query",
296	rc => "nxdomain",	411	rc => "nxdomain",
297		412
298	# flags	413	# flags
299	qr => 1,	414	qr => 1,
300	aa => 0,	415	aa => 0,
301	tc => 0,	416	tc => 0,
302	rd => 0,	417	rd => 0,
303	ra => 0,	418	ra => 0,
304	ad => 0,	419	ad => 0,
305	cd => 0,	420	cd => 0,
306		421
307	qd => [@rr], # query section	422	qd => [@rr], # query section
308	an => [@rr], # answer section	423	an => [@rr], # answer section
309	ns => [@rr], # authority section	424	ns => [@rr], # authority section
310	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
311	}	426	}
312		427
313	=cut	428	=cut
314		429
315	sub dns_pack($) {	430	sub dns_pack($) {
316	my ($req) = @_;	431	my ($req) = @_;
…		…
329	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
330		445
331	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
332	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
333	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
334	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
335		450
336	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
337	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
338	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
339	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
340		455
341	($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size	456	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
342	}	457	}
343		458
344	our $ofs;	459	our $ofs;
345	our $pkt;	460	our $pkt;
346		461
347	# bitches	462	# bitches
348	sub _dec_qname {	463	sub _dec_name {
349	my @res;	464	my @res;
350	my $redir;	465	my $redir;
351	my $ptr = $ofs;	466	my $ptr = $ofs;
352	my $cnt;	467	my $cnt;
353		468
354	while () {	469	while () {
355	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
356		471
357	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
358		473
359	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
360	$ptr++;	475	$ptr++;
361	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
362	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
363	} elsif ($len) {	478	} elsif ($len) {
364	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
369	}	484	}
370	}	485	}
371	}	486	}
372		487
373	sub _dec_qd {	488	sub _dec_qd {
374	my $qname = _dec_qname;	489	my $qname = _dec_name;
375	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
376	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
377	}	492	}
378		493
379	our %dec_rr = (	494	our %dec_rr = (
380	1 => sub { join ".", unpack "C4" }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
381	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
382	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
383	6 => sub {	498	6 => sub {
384	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
385	my $mname = _dec_qname;	500	my $mname = _dec_name;
386	my $rname = _dec_qname;	501	my $rname = _dec_name;
387	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
388	}, # soa	503	}, # soa
389	11 => sub { ((join ".", unpack "C4"), unpack "C a*", substr $_, 4) }, # wks	504	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
390	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
391	13 => sub { unpack "C/a C/a", $_ }, # hinfo	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
392	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx	507	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
393	16 => sub { unpack "(C/a)*", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
394	28 => sub { AnyEvent::Socket::format_ip ($_) }, # aaaa	509	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
395	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv	510	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		511	35 => sub { # naptr
		512	# requires perl 5.10, sorry
		513	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		514	local $ofs = $ofs + $offset - length;
		515	($order, $preference, $flags, $service, $regexp, _dec_name)
		516	},
		517	39 => sub { local $ofs = $ofs - length; _dec_name }, # dname
396	99 => sub { unpack "(C/a)*", $_ }, # spf	518	99 => sub { unpack "(C/a)", $_ }, # spf
397	);	519	);
398		520
399	sub _dec_rr {	521	sub _dec_rr {
400	my $qname = _dec_qname;	522	my $name = _dec_name;
401		523
402	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;	524	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
403	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
404		526
405	[	527	[
406	$qname,	528	$name,
407	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
408	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
409	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
410	]	532	]
411	}	533	}
…		…
414		536
415	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
416		538
417	Examples:	539	Examples:
418		540
419	# an unsuccessful reply	541	# an unsuccessful reply
420	{	542	{
421	'qd' => [	543	'qd' => [
422	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
423	],	545	],
424	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
425	'ar' => [],	547	'ar' => [],
426	'ns' => [	548	'ns' => [
427	[	549	[
428	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
429	'soa',	551	'soa',
430	'in',	552	'in',
431	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
432	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
433	2008052201, 10800, 1800, 2592000, 86400	555	2008052201, 10800, 1800, 2592000, 86400
434	]	556	]
435	],	557	],
436	'tc' => '',	558	'tc' => '',
437	'ra' => 1,	559	'ra' => 1,
438	'qr' => 1,	560	'qr' => 1,
439	'id' => 45915,	561	'id' => 45915,
440	'aa' => '',	562	'aa' => '',
441	'an' => [],	563	'an' => [],
442	'rd' => 1,	564	'rd' => 1,
443	'op' => 'query'	565	'op' => 'query'
444	}	566	}
445		567
446	# a successful reply	568	# a successful reply
447		569
448	{	570	{
449	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
450	'rc' => 0,	572	'rc' => 0,
451	'ar' => [	573	'ar' => [
452	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
453	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
454	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
455	],	577	],
456	'ns' => [	578	'ns' => [
457	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
458	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
459	],	581	],
460	'tc' => '',	582	'tc' => '',
461	'ra' => 1,	583	'ra' => 1,
462	'qr' => 1,	584	'qr' => 1,
463	'id' => 64265,	585	'id' => 64265,
464	'aa' => '',	586	'aa' => '',
465	'an' => [	587	'an' => [
466	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
467	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
468	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
469	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
470	],	592	],
471	'rd' => 1,	593	'rd' => 1,
472	'op' => 0	594	'op' => 0
473	}	595	}
474		596
475	=cut	597	=cut
476		598
477	sub dns_unpack($) {	599	sub dns_unpack($) {
478	local $pkt = shift;	600	local $pkt = shift;
…		…
533		655
534	our $RESOLVER;	656	our $RESOLVER;
535		657
536	sub resolver() {	658	sub resolver() {
537	$RESOLVER \|\| do {	659	$RESOLVER \|\| do {
538	$RESOLVER = new AnyEvent::DNS;	660	$RESOLVER = new AnyEvent::DNS untaint => 1;
539	$RESOLVER->os_config;	661	$RESOLVER->os_config;
540	$RESOLVER	662	$RESOLVER
541	}	663	}
542	}	664	}
543		665
…		…
549		671
550	=over 4	672	=over 4
551		673
552	=item server => [...]	674	=item server => [...]
553		675
554	A list of server addressses (default: C<v127.0.0.1>) in network format (4	676	A list of server addresses (default: C<v127.0.0.1>) in network format
555	octets for IPv4, 16 octets for IPv6 - not yet supported).	677	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		678	IPv6 are supported).
556		679
557	=item timeout => [...]	680	=item timeout => [...]
558		681
559	A list of timeouts to use (also determines the number of retries). To make	682	A list of timeouts to use (also determines the number of retries). To make
560	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	683	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
569	The number of dots (default: C<1>) that a name must have so that the resolver	692	The number of dots (default: C<1>) that a name must have so that the resolver
570	tries to resolve the name without any suffixes first.	693	tries to resolve the name without any suffixes first.
571		694
572	=item max_outstanding => $integer	695	=item max_outstanding => $integer
573		696
574	Most name servers do not handle many parallel requests very well. This option	697	Most name servers do not handle many parallel requests very well. This
575	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	698	option limits the number of outstanding requests to C<$integer>
576	if you request more than this many requests, then the additional requests will be queued	699	(default: C<10>), that means if you request more than this many requests,
577	until some other requests have been resolved.	700	then the additional requests will be queued until some other requests have
		701	been resolved.
578		702
579	=item reuse => $seconds	703	=item reuse => $seconds
580		704
581	The number of seconds (default: C<60>) that a query id cannot be re-used	705	The number of seconds (default: C<300>) that a query id cannot be re-used
582	after a request. Since AnyEvent::DNS will only allocate up to 30000 ID's	706	after a timeout. If there was no time-out then query ids can be reused
583	at the same time, the long-term maximum number of requests per second is	707	immediately.
584	C<30000 / $seconds> (and thus C<500> requests/s by default).	708
		709	=item untaint => $boolean
		710
		711	When true, then the resolver will automatically untaint results, and might
		712	also ignore certain environment variables.
585		713
586	=back	714	=back
587		715
588	=cut	716	=cut
589		717
590	sub new {	718	sub new {
591	my ($class, %arg) = @_;	719	my ($class, %arg) = @_;
592		720
593	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
594	or Carp::croak "socket: $!";
595
596	AnyEvent::Util::fh_nonblocking $fh, 1;
597
598	my $self = bless {	721	my $self = bless {
599	server => [v127.0.0.1],	722	server => [],
600	timeout => [2, 5, 5],	723	timeout => [2, 5, 5],
601	search => [],	724	search => [],
602	ndots => 1,	725	ndots => 1,
603	max_outstanding => 10,	726	max_outstanding => 10,
604	reuse => 60, # reuse id's after 5 minutes only, if possible	727	reuse => 300,
605	%arg,	728	%arg,
606	fh => $fh,
607	reuse_q => [],	729	reuse_q => [],
608	}, $class;	730	}, $class;
609		731
610	# search should default to gethostname's domain	732	# search should default to gethostname's domain
611	# but perl lacks a good posix module	733	# but perl lacks a good posix module
612		734
		735	# try to create an ipv4 and an ipv6 socket
		736	# only fail when we cannot create either
		737	my $got_socket;
		738
613	Scalar::Util::weaken (my $wself = $self);	739	Scalar::Util::weaken (my $wself = $self);
		740
		741	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		742	++$got_socket;
		743
		744	AnyEvent::Util::fh_nonblocking $fh4, 1;
		745	$self->{fh4} = $fh4;
614	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	746	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		747	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		748	$wself->_recv ($pkt, $peer);
		749	}
		750	});
		751	}
		752
		753	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		754	++$got_socket;
		755
		756	$self->{fh6} = $fh6;
		757	AnyEvent::Util::fh_nonblocking $fh6, 1;
		758	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		759	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		760	$wself->_recv ($pkt, $peer);
		761	}
		762	});
		763	}
		764
		765	$got_socket
		766	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
615		767
616	$self->_compile;	768	$self->_compile;
617		769
618	$self	770	$self
619	}	771	}
620		772
621	=item $resolver->parse_resolv_conv ($string)	773	=item $resolver->parse_resolv_conv ($string)
622		774
623	Parses the given string a sif it were a F<resolv.conf> file. The following	775	Parses the given string as if it were a F<resolv.conf> file. The following
624	directives are supported (but not neecssarily implemented).	776	directives are supported (but not necessarily implemented).
625		777
626	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	778	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
627	C<options> (C<timeout>, C<attempts>, C<ndots>).	779	C<options> (C<timeout>, C<attempts>, C<ndots>).
628		780
629	Everything else is silently ignored.	781	Everything else is silently ignored.
…		…
641	for (split /\n/, $resolvconf) {	793	for (split /\n/, $resolvconf) {
642	if (/^\s*#/) {	794	if (/^\s*#/) {
643	# comment	795	# comment
644	} elsif (/^\snameserver\s+(\S+)\s$/i) {	796	} elsif (/^\snameserver\s+(\S+)\s$/i) {
645	my $ip = $1;	797	my $ip = $1;
646	if (AnyEvent::Util::dotted_quad $ip) {	798	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
647	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	799	push @{ $self->{server} }, $ipn;
648	} else {	800	} else {
649	warn "nameserver $ip invalid and ignored\n";	801	warn "nameserver $ip invalid and ignored\n";
650	}	802	}
651	} elsif (/^\sdomain\s+(\S)\s+$/i) {	803	} elsif (/^\sdomain\s+(\S)\s+$/i) {
652	$self->{search} = [$1];	804	$self->{search} = [$1];
…		…
675	$self->_compile;	827	$self->_compile;
676	}	828	}
677		829
678	=item $resolver->os_config	830	=item $resolver->os_config
679		831
680	Tries so load and parse F</etc/resolv.conf> on portable opertaing systems. Tries various	832	Tries so load and parse F</etc/resolv.conf> on portable operating
681	egregious hacks on windows to force the dns servers and searchlist out of the config.	833	systems. Tries various egregious hacks on windows to force the DNS servers
		834	and searchlist out of the system.
682		835
683	=cut	836	=cut
684		837
685	sub os_config {	838	sub os_config {
686	my ($self) = @_;	839	my ($self) = @_;
687		840
688	if ($^O =~ /mswin32\|cygwin/i) {	841	$self->{server} = [];
689	# yeah, it suxx... lets hope DNS is DNS in all locales	842	$self->{search} = [];
		843
		844	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		845	no strict 'refs';
		846
		847	# there are many options to find the current nameservers etc. on windows
		848	# all of them don't work consistently:
		849	# - the registry thing needs separate code on win32 native vs. cygwin
		850	# - the registry layout differs between windows versions
		851	# - calling windows api functions doesn't work on cygwin
		852	# - ipconfig uses locale-specific messages
		853
		854	# we use ipconfig parsing because, despite all its brokenness,
		855	# it seems most stable in practise.
		856	# for good measure, we append a fallback nameserver to our list.
690		857
691	if (open my $fh, "ipconfig /all \|") {	858	if (open my $fh, "ipconfig /all \|") {
692	delete $self->{server};	859	# parsing strategy: we go through the output and look for
693	delete $self->{search};	860	# :-lines with DNS in them. everything in those is regarded as
		861	# either a nameserver (if it parses as an ip address), or a suffix
		862	# (all else).
694		863
		864	my $dns;
695	while (<$fh>) {	865	while (<$fh>) {
696	# first DNS.* is suffix list	866	if (s/^\s.\bdns\b.://i) {
697	if (/^\s*DNS/) {	867	$dns = 1;
698	while (/\s+([[:alnum:].\-]+)\s*$/) {	868	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		869	$dns = 0;
		870	}
		871	if ($dns && /^\s(\S+)\s$/) {
		872	my $s = $1;
		873	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		874	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		875	push @{ $self->{server} }, $ipn;
		876	} else {
699	push @{ $self->{search} }, $1;	877	push @{ $self->{search} }, $s;
700	$_ = <$fh>;
701	}	878	}
702	last;
703	}	879	}
704	}	880	}
705		881
706	while (<$fh>) {	882	# always add one fallback server
707	# second DNS.* is server address list	883	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
708	if (/^\s*DNS/) {
709	while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) {
710	my $ip = $1;
711	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip
712	if AnyEvent::Util::dotted_quad $ip;
713	$_ = <$fh>;
714	}
715	last;
716	}
717	}
718		884
719	$self->_compile;	885	$self->_compile;
720	}	886	}
721	} else {	887	} else {
722	# try resolv.conf everywhere	888	# try resolv.conf everywhere
…		…
726	$self->parse_resolv_conf (<$fh>);	892	$self->parse_resolv_conf (<$fh>);
727	}	893	}
728	}	894	}
729	}	895	}
730		896
		897	=item $resolver->timeout ($timeout, ...)
		898
		899	Sets the timeout values. See the C<timeout> constructor argument (and note
		900	that this method uses the values itself, not an array-reference).
		901
		902	=cut
		903
		904	sub timeout {
		905	my ($self, @timeout) = @_;
		906
		907	$self->{timeout} = \@timeout;
		908	$self->_compile;
		909	}
		910
		911	=item $resolver->max_outstanding ($nrequests)
		912
		913	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		914	C<max_outstanding> constructor argument.
		915
		916	=cut
		917
		918	sub max_outstanding {
		919	my ($self, $max) = @_;
		920
		921	$self->{max_outstanding} = $max;
		922	$self->_scheduler;
		923	}
		924
731	sub _compile {	925	sub _compile {
732	my $self = shift;	926	my $self = shift;
		927
		928	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		929	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		930
		931	unless (@{ $self->{server} }) {
		932	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		933	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		934	}
733		935
734	my @retry;	936	my @retry;
735		937
736	for my $timeout (@{ $self->{timeout} }) {	938	for my $timeout (@{ $self->{timeout} }) {
737	for my $server (@{ $self->{server} }) {	939	for my $server (@{ $self->{server} }) {
…		…
743	}	945	}
744		946
745	sub _feed {	947	sub _feed {
746	my ($self, $res) = @_;	948	my ($self, $res) = @_;
747		949
		950	($res) = $res =~ /^(.*)$/s
		951	if AnyEvent::TAINT && $self->{untaint};
		952
748	$res = dns_unpack $res	953	$res = dns_unpack $res
749	or return;	954	or return;
750		955
751	my $id = $self->{id}{$res->{id}};	956	my $id = $self->{id}{$res->{id}};
752		957
…		…
755	$NOW = time;	960	$NOW = time;
756	$id->[1]->($res);	961	$id->[1]->($res);
757	}	962	}
758		963
759	sub _recv {	964	sub _recv {
760	my ($self) = @_;	965	my ($self, $pkt, $peer) = @_;
761		966
762	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	967	# we ignore errors (often one gets port unreachable, but there is
		968	# no good way to take advantage of that.
		969
763	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	970	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
764		971
765	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	972	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
766		973
767	$self->_feed ($res);	974	$self->_feed ($pkt);
768	}
769	}	975	}
770		976
		977	sub _free_id {
		978	my ($self, $id, $timeout) = @_;
		979
		980	if ($timeout) {
		981	# we need to block the id for a while
		982	$self->{id}{$id} = 1;
		983	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		984	} else {
		985	# we can quickly recycle the id
		986	delete $self->{id}{$id};
		987	}
		988
		989	--$self->{outstanding};
		990	$self->_scheduler;
		991	}
		992
		993	# execute a single request, involves sending it with timeouts to multiple servers
771	sub _exec {	994	sub _exec {
772	my ($self, $req, $retry) = @_;	995	my ($self, $req) = @_;
773		996
		997	my $retry; # of retries
		998	my $do_retry;
		999
		1000	$do_retry = sub {
774	if (my $retry_cfg = $self->{retry}[$retry]) {	1001	my $retry_cfg = $self->{retry}[$retry++]
		1002	or do {
		1003	# failure
		1004	$self->_free_id ($req->[2], $retry > 1);
		1005	undef $do_retry; return $req->[1]->();
		1006	};
		1007
775	my ($server, $timeout) = @$retry_cfg;	1008	my ($server, $timeout) = @$retry_cfg;
776		1009
777	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1010	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
778	$NOW = time;	1011	$NOW = time;
779		1012
780	# timeout, try next	1013	# timeout, try next
781	$self->_exec ($req, $retry + 1);	1014	&$do_retry if $do_retry;
782	}), sub {	1015	}), sub {
783	my ($res) = @_;	1016	my ($res) = @_;
784		1017
785	if ($res->{tc}) {	1018	if ($res->{tc}) {
786	# success, but truncated, so use tcp	1019	# success, but truncated, so use tcp
787	AnyEvent::Socket::tcp_connect ((Socket::inet_ntoa $server), 53, sub {	1020	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1021	return unless $do_retry; # some other request could have invalidated us already
		1022
788	my ($fh) = @_	1023	my ($fh) = @_
789	or return $self->_exec ($req, $retry + 1);	1024	or return &$do_retry;
790		1025
791	my $handle = new AnyEvent::Handle	1026	my $handle; $handle = new AnyEvent::Handle
792	fh => $fh,	1027	fh => $fh,
		1028	timeout => $timeout,
793	on_error => sub {	1029	on_error => sub {
		1030	undef $handle;
		1031	return unless $do_retry; # some other request could have invalidated us already
794	# failure, try next	1032	# failure, try next
795	$self->_exec ($req, $retry + 1);	1033	&$do_retry;
796	};	1034	};
797		1035
798	$handle->push_write (pack "n/a", $req->[0]);	1036	$handle->push_write (pack "n/a", $req->[0]);
799	$handle->push_read_chunk (2, sub {	1037	$handle->push_read (chunk => 2, sub {
800	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1038	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1039	undef $handle;
801	$self->_feed ($_[1]);	1040	$self->_feed ($_[1]);
802	});	1041	});
803	});	1042	});
804	shutdown $fh, 1;
805		1043
806	}, sub { $timeout });	1044	}, sub { $timeout });
807		1045
808	} else {	1046	} else {
809	# success	1047	# success
810	$self->{id}{$req->[2]} = 1;	1048	$self->_free_id ($req->[2], $retry > 1);
811	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1049	undef $do_retry; return $req->[1]->($res);
812	--$self->{outstanding};
813	$self->_scheduler;
814
815	$req->[1]->($res);
816	}	1050	}
817	}];	1051	}];
		1052
		1053	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
818		1054
819	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1055	my $fh = AF_INET == Socket::sockaddr_family ($sa)
820	} else {	1056	? $self->{fh4} : $self->{fh6}
821	# failure	1057	or return &$do_retry;
822	$self->{id}{$req->[2]} = 1;
823	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
824	--$self->{outstanding};
825	$self->_scheduler;
826		1058
827	$req->[1]->();	1059	send $fh, $req->[0], 0, $sa;
828	}	1060	};
		1061
		1062	&$do_retry;
829	}	1063	}
830		1064
831	sub _scheduler {	1065	sub _scheduler {
832	my ($self) = @_;	1066	my ($self) = @_;
		1067
		1068	no strict 'refs';
833		1069
834	$NOW = time;	1070	$NOW = time;
835		1071
836	# first clear id reuse queue	1072	# first clear id reuse queue
837	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1073	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
846	$self->_scheduler;	1082	$self->_scheduler;
847	});	1083	});
848	last;	1084	last;
849	}	1085	}
850		1086
851	my $req = shift @{ $self->{queue} }	1087	if (my $req = shift @{ $self->{queue} }) {
852	or last;	1088	# found a request in the queue, execute it
853
854	while () {	1089	while () {
855	$req->[2] = int rand 65536;	1090	$req->[2] = int rand 65536;
856	last unless exists $self->{id}{$req->[2]};	1091	last unless exists $self->{id}{$req->[2]};
		1092	}
		1093
		1094	++$self->{outstanding};
		1095	$self->{id}{$req->[2]} = 1;
		1096	substr $req->[0], 0, 2, pack "n", $req->[2];
		1097
		1098	$self->_exec ($req);
		1099
		1100	} elsif (my $cb = shift @{ $self->{wait} }) {
		1101	# found a wait_for_slot callback, call that one first
		1102	$cb->($self);
		1103
		1104	} else {
		1105	# nothing to do, just exit
		1106	last;
857	}	1107	}
858
859	$self->{id}{$req->[2]} = 1;
860	substr $req->[0], 0, 2, pack "n", $req->[2];
861
862	++$self->{outstanding};
863	$self->_exec ($req, 0);
864	}	1108	}
865	}	1109	}
866		1110
867	=item $resolver->request ($req, $cb->($res))	1111	=item $resolver->request ($req, $cb->($res))
868		1112
		1113	This is the main low-level workhorse for sending DNS requests.
		1114
869	Sends a single request (a hash-ref formated as specified for	1115	This function sends a single request (a hash-ref formated as specified
870	C<dns_pack>) to the configured nameservers including	1116	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1117	response. It handles timeouts, retries and automatically falls back to
		1118	virtual circuit mode (TCP) when it receives a truncated reply.
		1119
871	retries. Calls the callback with the decoded response packet if a reply	1120	Calls the callback with the decoded response packet if a reply was
872	was received, or no arguments on timeout.	1121	received, or no arguments in case none of the servers answered.
873		1122
874	=cut	1123	=cut
875		1124
876	sub request($$) {	1125	sub request($$) {
877	my ($self, $req, $cb) = @_;	1126	my ($self, $req, $cb) = @_;
878		1127
879	push @{ $self->{queue} }, [dns_pack $req, $cb];	1128	push @{ $self->{queue} }, [dns_pack $req, $cb];
880	$self->_scheduler;	1129	$self->_scheduler;
881	}	1130	}
882		1131
883	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1132	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
884		1133
885	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1134	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
886	qtype of "*" is supported and means "any").	1135
		1136	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1137	a lowercase name (you have to look at the source to see which aliases are
		1138	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1139	more are known to this module). A C<$qtype> of "*" is supported and means
		1140	"any" record type.
887		1141
888	The callback will be invoked with a list of matching result records or	1142	The callback will be invoked with a list of matching result records or
889	none on any error or if the name could not be found.	1143	none on any error or if the name could not be found.
890		1144
891	CNAME chains (although illegal) are followed up to a length of 8.	1145	CNAME chains (although illegal) are followed up to a length of 10.
892		1146
		1147	The callback will be invoked with arraryefs of the form C<[$name, $type,
		1148	$class, @data>], where C<$name> is the domain name, C<$type> a type string
		1149	or number, C<$class> a class name and @data is resource-record-dependent
		1150	data. For C<a> records, this will be the textual IPv4 addresses, for C<ns>
		1151	or C<cname> records this will be a domain name, for C<txt> records these
		1152	are all the strings and so on.
		1153
		1154	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1155	decoded. All resource records not known to this module will have
		1156	the raw C<rdata> field as fourth entry.
		1157
893	Note that this resolver is just a stub resolver: it requires a nameserver	1158	Note that this resolver is just a stub resolver: it requires a name server
894	supporting recursive queries, will not do any recursive queries itself and	1159	supporting recursive queries, will not do any recursive queries itself and
895	is not secure when used against an untrusted name server.	1160	is not secure when used against an untrusted name server.
896		1161
897	The following options are supported:	1162	The following options are supported:
898		1163
…		…
900		1165
901	=item search => [$suffix...]	1166	=item search => [$suffix...]
902		1167
903	Use the given search list (which might be empty), by appending each one	1168	Use the given search list (which might be empty), by appending each one
904	in turn to the C<$qname>. If this option is missing then the configured	1169	in turn to the C<$qname>. If this option is missing then the configured
905	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1170	C<ndots> and C<search> values define its value (depending on C<ndots>, the
906	then the searchlist will be ignored.	1171	empty suffix will be prepended or appended to that C<search> value). If
		1172	the C<$qname> ends in a dot, then the searchlist will be ignored.
907		1173
908	=item accept => [$type...]	1174	=item accept => [$type...]
909		1175
910	Lists the acceptable result types: only result types in this set will be	1176	Lists the acceptable result types: only result types in this set will be
911	accepted and returned. The default includes the C<$qtype> and nothing	1177	accepted and returned. The default includes the C<$qtype> and nothing
912	else.	1178	else. If this list includes C<cname>, then CNAME-chains will not be
		1179	followed (because you asked for the CNAME record).
913		1180
914	=item class => "class"	1181	=item class => "class"
915		1182
916	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1183	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
917	hesiod are the only ones making sense). The default is "in", of course.	1184	hesiod are the only ones making sense). The default is "in", of course.
918		1185
919	=back	1186	=back
920		1187
921	Examples:	1188	Examples:
922		1189
923	$res->resolve ("ruth.plan9.de", "a", sub {	1190	# full example, you can paste this into perl:
924	warn Dumper [@_];	1191	use Data::Dumper;
925	});	1192	use AnyEvent::DNS;
		1193	AnyEvent::DNS::resolver->resolve (
		1194	"google.com", "*", my $cv = AnyEvent->condvar);
		1195	warn Dumper [$cv->recv];
926		1196
		1197	# shortened result:
927	[	1198	# [
		1199	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1200	# 2008052701, 7200, 1800, 1209600, 300 ],
928	[	1201	# [
929	'ruth.schmorp.de',	1202	# 'google.com', 'txt', 'in',
930	'a',	1203	# 'v=spf1 include:_netblocks.google.com ~all'
931	'in',	1204	# ],
932	'129.13.162.95'	1205	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1206	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1207	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
933	]	1208	# ]
		1209
		1210	# resolve a records:
		1211	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1212
		1213	# result:
		1214	# [
		1215	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
934	]	1216	# ]
935		1217
		1218	# resolve any records, but return only a and aaaa records:
936	$res->resolve ("test1.laendle", "*",	1219	$res->resolve ("test1.laendle", "*",
937	accept => ["a", "aaaa"],	1220	accept => ["a", "aaaa"],
938	sub {	1221	sub {
939	warn Dumper [@_];	1222	warn Dumper [@_];
940	}	1223	}
941	);	1224	);
942		1225
943	[	1226	# result:
944	[	1227	# [
945	'test1.laendle',	1228	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
946	'a',	1229	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
947	'in',
948	'10.0.0.255'
949	],
950	[
951	'test1.laendle',
952	'aaaa',
953	'in',
954	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
955	]	1230	# ]
956	]
957		1231
958	=cut	1232	=cut
959		1233
960	sub resolve($%) {	1234	sub resolve($%) {
961	my $cb = pop;	1235	my $cb = pop;
…		…
974	my %atype = $opt{accept}	1248	my %atype = $opt{accept}
975	? map +($_ => 1), @{ $opt{accept} }	1249	? map +($_ => 1), @{ $opt{accept} }
976	: ($qtype => 1);	1250	: ($qtype => 1);
977		1251
978	# advance in searchlist	1252	# advance in searchlist
979	my $do_search; $do_search = sub {	1253	my ($do_search, $do_req);
		1254
		1255	$do_search = sub {
980	@search	1256	@search
981	or return $cb->();	1257	or (undef $do_search), (undef $do_req), return $cb->();
982		1258
983	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1259	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
984	my $depth = 2;	1260	my $depth = 10;
985		1261
986	# advance in cname-chain	1262	# advance in cname-chain
987	my $do_req; $do_req = sub {	1263	$do_req = sub {
988	$self->request ({	1264	$self->request ({
989	rd => 1,	1265	rd => 1,
990	qd => [[$name, $qtype, $class]],	1266	qd => [[$name, $qtype, $class]],
991	}, sub {	1267	}, sub {
992	my ($res) = @_	1268	my ($res) = @_
…		…
996		1272
997	while () {	1273	while () {
998	# results found?	1274	# results found?
999	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1275	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
1000		1276
1001	return $cb->(@rr)	1277	(undef $do_search), (undef $do_req), return $cb->(@rr)
1002	if @rr;	1278	if @rr;
1003		1279
1004	# see if there is a cname we can follow	1280	# see if there is a cname we can follow
1005	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1281	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
1006		1282
…		…
1027	};	1303	};
1028		1304
1029	$do_search->();	1305	$do_search->();
1030	}	1306	}
1031		1307
		1308	=item $resolver->wait_for_slot ($cb->($resolver))
		1309
		1310	Wait until a free request slot is available and call the callback with the
		1311	resolver object.
		1312
		1313	A request slot is used each time a request is actually sent to the
		1314	nameservers: There are never more than C<max_outstanding> of them.
		1315
		1316	Although you can submit more requests (they will simply be queued until
		1317	a request slot becomes available), sometimes, usually for rate-limiting
		1318	purposes, it is useful to instead wait for a slot before generating the
		1319	request (or simply to know when the request load is low enough so one can
		1320	submit requests again).
		1321
		1322	This is what this method does: The callback will be called when submitting
		1323	a DNS request will not result in that request being queued. The callback
		1324	may or may not generate any requests in response.
		1325
		1326	Note that the callback will only be invoked when the request queue is
		1327	empty, so this does not play well if somebody else keeps the request queue
		1328	full at all times.
		1329
		1330	=cut
		1331
		1332	sub wait_for_slot {
		1333	my ($self, $cb) = @_;
		1334
		1335	push @{ $self->{wait} }, $cb;
		1336	$self->_scheduler;
		1337	}
		1338
1032	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end	1339	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
1033		1340
1034	1;	1341	1;
1035		1342
1036	=back	1343	=back
1037		1344
1038	=head1 AUTHOR	1345	=head1 AUTHOR
1039		1346
1040	Marc Lehmann <schmorp@schmorp.de>	1347	Marc Lehmann <schmorp@schmorp.de>
1041	http://home.schmorp.de/	1348	http://home.schmorp.de/
1042		1349
1043	=cut	1350	=cut
1044		1351

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.17 by root, Fri May 23 20:21:50 2008 UTC vs. Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.17 by root, Fri May 23 20:21:50 2008 UTC vs.
Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC