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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.7 by root, Fri May 23 05:30:59 2008 UTC vs.
Revision 1.75 by root, Thu Aug 21 23:48:35 2008 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
		19	The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional
		20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
		21	virtual circuit mode for large responses.
		22
14	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
15		24
16	=over 4	25	=over 4
17		26
18	=cut	27	=cut
…		…
20	package AnyEvent::DNS;	29	package AnyEvent::DNS;
21		30
22	no warnings;	31	no warnings;
23	use strict;	32	use strict;
24		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
25	use AnyEvent::Util ();	36	use AnyEvent ();
26	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
27		39
28	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.233;
29		41
30	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
31
32	Tries to resolve the given nodename and service name into sockaddr
33	structures usable to connect to this node and service in a
34	protocol-independent way. It works similarly to the getaddrinfo posix
35	function.
36
37	Example:
38
39	AnyEvent::DNS::addr "google.com", "http", AF_UNSPEC, SOCK_STREAM, sub { ... };
40		43
41	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
42		45
43	Tries to resolve the given domain to IPv4 address(es).	46	Tries to resolve the given domain to IPv4 address(es).
		47
		48	=item AnyEvent::DNS::aaaa $domain, $cb->(@addrs)
		49
		50	Tries to resolve the given domain to IPv6 address(es).
44		51
45	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)	52	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)
46		53
47	Tries to resolve the given domain into a sorted (lower preference value	54	Tries to resolve the given domain into a sorted (lower preference value
48	first) list of domain names.	55	first) list of domain names.
…		…
58	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
59		66
60	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
61	of service records.	68	of service records.
62		69
63	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
64	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
65		72
66	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
67	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
68		75
69	Example:	76	Example:
70		77
71	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
72	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
73		80
74	=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)
75		93
76	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)
77	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
78		97
79	Requires the Socket6 module for IPv6 support.	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.
80		108
81	Example:	109	Example:
82		110
83	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
84	# => f.root-servers.net	112	# => f.root-servers.net
85		113
86	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
87
88	Tries to resolve the given domain and passes all resource records found to
89	the callback.
90
91	=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
92		119
93	sub resolver;	120	sub resolver;
94		121
95	sub a($$) {	122	sub a($$) {
96	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
98	resolver->resolve ($domain => "a", sub {	125	resolver->resolve ($domain => "a", sub {
99	$cb->(map $_->[3], @_);	126	$cb->(map $_->[3], @_);
100	});	127	});
101	}	128	}
102		129
		130	sub aaaa($$) {
		131	my ($domain, $cb) = @_;
		132
		133	resolver->resolve ($domain => "aaaa", sub {
		134	$cb->(map $_->[3], @_);
		135	});
		136	}
		137
103	sub mx($$) {	138	sub mx($$) {
104	my ($domain, $cb) = @_;	139	my ($domain, $cb) = @_;
105		140
106	resolver->resolve ($domain => "mx", sub {	141	resolver->resolve ($domain => "mx", sub {
107	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);	142	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);
…		…
127	sub srv($$$$) {	162	sub srv($$$$) {
128	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
129		164
130	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
131	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
132	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
133	});	194	});
134	}	195	}
135		196
136	sub ptr($$) {	197	sub ptr($$) {
137	my ($ip, $cb) = @_;	198	my ($domain, $cb) = @_;
138		199
139	my $name;
140
141	if (AnyEvent::Util::dotted_quad $ip) {
142	$name = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
143	} else {
144	require Socket6;
145	$name = join ".",
146	(reverse split //,
147	unpack "H*", Socket6::inet_pton (Socket::AF_INET6, $ip)),
148	"ip6.arpa.";
149	}
150
151	resolver->resolve ($name => "ptr", sub {	200	resolver->resolve ($domain => "ptr", sub {
152	$cb->(map $_->[3], @_);	201	$cb->(map $_->[3], @_);
153	});	202	});
154	}	203	}
155		204
156	sub any($$) {	205	sub any($$) {
157	my ($domain, $cb) = @_;	206	my ($domain, $cb) = @_;
158		207
159	resolver->resolve ($domain => "*", $cb);	208	resolver->resolve ($domain => "*", $cb);
160	}	209	}
161		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
		239	my ($ip, $cb) = @_;
		240
		241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
		242	or return $cb->();
		243
		244	resolver->resolve ($ip => "ptr", sub {
		245	$cb->(map $_->[3], @_);
		246	});
		247	}
		248
		249	sub reverse_verify($$) {
		250	my ($ip, $cb) = @_;
		251
		252	my $ipn = AnyEvent::Socket::parse_address ($ip)
		253	or return $cb->();
		254
		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	};
		281	}
		282
		283	#################################################################################
		284
		285	=back
		286
162	=head2 DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
163		288
164	=over 4	289	=over 4
165		290
		291	=item $AnyEvent::DNS::EDNS0
		292
		293	This variable decides whether dns_pack automatically enables EDNS0
		294	support. By default, this is disabled (C<0>), unless overridden by
		295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
		296	EDNS0 in all requests.
		297
166	=cut	298	=cut
		299
		300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0
167		301
168	our %opcode_id = (	302	our %opcode_id = (
169	query => 0,	303	query => 0,
170	iquery => 1,	304	iquery => 1,
171	status => 2,	305	status => 2,
…		…
217	minfo => 14,	351	minfo => 14,
218	mx => 15,	352	mx => 15,
219	txt => 16,	353	txt => 16,
220	aaaa => 28,	354	aaaa => 28,
221	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
222	opt => 41,	357	opt => 41,
223	spf => 99,	358	spf => 99,
224	tkey => 249,	359	tkey => 249,
225	tsig => 250,	360	tsig => 250,
226	ixfr => 251,	361	ixfr => 251,
…		…
239	"*" => 255,	374	"*" => 255,
240	);	375	);
241		376
242	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
243		378
244	# names MUST have a trailing dot
245	sub _enc_qname($) {	379	sub _enc_name($) {
246	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
247	}	381	}
248		382
249	sub _enc_qd() {	383	sub _enc_qd() {
250	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
251	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
252	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
253	}	387	}
254		388
255	sub _enc_rr() {	389	sub _enc_rr() {
256	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
257	}	391	}
258		392
259	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
260		394
261	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	395	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
262	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
263		397
264	Resource records are not yet encodable.	398	Resource records are not yet encodable.
265		399
266	Examples:	400	Examples:
267		401
268	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
269	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
270		404
271	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
272		406
273	{	407	{
274	id => 10000,	408	id => 10000,
275	op => "query",	409	op => "query",
276	rc => "nxdomain",	410	rc => "nxdomain",
277		411
278	# flags	412	# flags
279	qr => 1,	413	qr => 1,
280	aa => 0,	414	aa => 0,
281	tc => 0,	415	tc => 0,
282	rd => 0,	416	rd => 0,
283	ra => 0,	417	ra => 0,
284	ad => 0,	418	ad => 0,
285	cd => 0,	419	cd => 0,
286		420
287	qd => [@rr], # query section	421	qd => [@rr], # query section
288	an => [@rr], # answer section	422	an => [@rr], # answer section
289	ns => [@rr], # authority section	423	ns => [@rr], # authority section
290	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
291	}	425	}
292		426
293	=cut	427	=cut
294		428
295	sub dns_pack($) {	429	sub dns_pack($) {
296	my ($req) = @_;	430	my ($req) = @_;
…		…
309	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
310		444
311	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
312	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
313	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
314	1 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
315		449
316	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
317	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
318	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
319	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
320		454
321	(pack "C nnNn", 0, 41, 4000, 0, 0) # EDNS0, 4k udp payload size	455	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
322	}	456	}
323		457
324	our $ofs;	458	our $ofs;
325	our $pkt;	459	our $pkt;
326		460
327	# bitches	461	# bitches
328	sub _dec_qname {	462	sub _dec_name {
329	my @res;	463	my @res;
330	my $redir;	464	my $redir;
331	my $ptr = $ofs;	465	my $ptr = $ofs;
332	my $cnt;	466	my $cnt;
333		467
334	while () {	468	while () {
335	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
336		470
337	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
338		472
339	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
340	$ptr++;	474	$ptr++;
341	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
342	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
343	} elsif ($len) {	477	} elsif ($len) {
344	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
349	}	483	}
350	}	484	}
351	}	485	}
352		486
353	sub _dec_qd {	487	sub _dec_qd {
354	my $qname = _dec_qname;	488	my $qname = _dec_name;
355	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
356	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
357	}	491	}
358		492
359	our %dec_rr = (	493	our %dec_rr = (
360	1 => sub { Socket::inet_ntoa $_ }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
361	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
362	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
363	6 => sub {	497	6 => sub {
364	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
365	my $mname = _dec_qname;	499	my $mname = _dec_name;
366	my $rname = _dec_qname;	500	my $rname = _dec_name;
367	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
368	}, # soa	502	}, # soa
369	11 => sub { ((Socket::inet_aton substr $_, 0, 4), unpack "C a*", substr $_, 4) }, # wks	503	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
370	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
371	13 => sub { unpack "C/a C/a", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
372	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx	506	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
373	16 => sub { unpack "(C/a)*", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
374	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
375	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv	509	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		510	35 => sub { # naptr
		511	# requires perl 5.10, sorry
		512	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		513	local $ofs = $ofs + $offset - length;
		514	($order, $preference, $flags, $service, $regexp, _dec_name)
		515	},
376	99 => sub { unpack "(C/a)*", $_ }, # spf	516	99 => sub { unpack "(C/a)", $_ }, # spf
377	);	517	);
378		518
379	sub _dec_rr {	519	sub _dec_rr {
380	my $qname = _dec_qname;	520	my $name = _dec_name;
381		521
382	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;	522	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
383	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
384		524
385	[	525	[
386	$qname,	526	$name,
387	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
388	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
389	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
390	]	530	]
391	}	531	}
…		…
394		534
395	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
396		536
397	Examples:	537	Examples:
398		538
399	# a non-successful reply	539	# an unsuccessful reply
400	{	540	{
401	'qd' => [	541	'qd' => [
402	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
403	],	543	],
404	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
405	'ar' => [],	545	'ar' => [],
406	'ns' => [	546	'ns' => [
407	[	547	[
408	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
409	'soa',	549	'soa',
410	'in',	550	'in',
411	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
412	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
413	2008052201,	553	2008052201, 10800, 1800, 2592000, 86400
414	10800,
415	1800,
416	2592000,
417	86400
418	]	554	]
419	],	555	],
420	'tc' => '',	556	'tc' => '',
421	'ra' => 1,	557	'ra' => 1,
422	'qr' => 1,	558	'qr' => 1,
423	'id' => 45915,	559	'id' => 45915,
424	'aa' => '',	560	'aa' => '',
425	'an' => [],	561	'an' => [],
426	'rd' => 1,	562	'rd' => 1,
427	'op' => 'query'	563	'op' => 'query'
428	}	564	}
429		565
430	# a successful reply	566	# a successful reply
431		567
432	{	568	{
433	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
434	'rc' => 0,	570	'rc' => 0,
435	'ar' => [	571	'ar' => [
436	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
437	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
438	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
439	],	575	],
440	'ns' => [	576	'ns' => [
441	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
442	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
443	],	579	],
444	'tc' => '',	580	'tc' => '',
445	'ra' => 1,	581	'ra' => 1,
446	'qr' => 1,	582	'qr' => 1,
447	'id' => 64265,	583	'id' => 64265,
448	'aa' => '',	584	'aa' => '',
449	'an' => [	585	'an' => [
450	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
451	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
452	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
453	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
454	],	590	],
455	'rd' => 1,	591	'rd' => 1,
456	'op' => 0	592	'op' => 0
457	}	593	}
458		594
459	=cut	595	=cut
460		596
461	sub dns_unpack($) {	597	sub dns_unpack($) {
462	local $pkt = shift;	598	local $pkt = shift;
…		…
488		624
489	=back	625	=back
490		626
491	=head2 THE AnyEvent::DNS RESOLVER CLASS	627	=head2 THE AnyEvent::DNS RESOLVER CLASS
492		628
493	This is the class which deos the actual protocol work.	629	This is the class which does the actual protocol work.
494		630
495	=over 4	631	=over 4
496		632
497	=cut	633	=cut
498		634
…		…
518	our $RESOLVER;	654	our $RESOLVER;
519		655
520	sub resolver() {	656	sub resolver() {
521	$RESOLVER \|\| do {	657	$RESOLVER \|\| do {
522	$RESOLVER = new AnyEvent::DNS;	658	$RESOLVER = new AnyEvent::DNS;
523	$RESOLVER->load_resolv_conf;	659	$RESOLVER->os_config;
524	$RESOLVER	660	$RESOLVER
525	}	661	}
526	}	662	}
527		663
528	=item $resolver = new AnyEvent::DNS key => value...	664	=item $resolver = new AnyEvent::DNS key => value...
…		…
533		669
534	=over 4	670	=over 4
535		671
536	=item server => [...]	672	=item server => [...]
537		673
538	A list of server addressses (default C<v127.0.0.1>) in network format (4	674	A list of server addresses (default: C<v127.0.0.1>) in network format
539	octets for IPv4, 16 octets for IPv6 - not yet supported).	675	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		676	IPv6 are supported).
540		677
541	=item timeout => [...]	678	=item timeout => [...]
542		679
543	A list of timeouts to use (also determines the number of retries). To make	680	A list of timeouts to use (also determines the number of retries). To make
544	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	681	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
553	The number of dots (default: C<1>) that a name must have so that the resolver	690	The number of dots (default: C<1>) that a name must have so that the resolver
554	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
555		692
556	=item max_outstanding => $integer	693	=item max_outstanding => $integer
557		694
558	Most name servers do not handle many parallel requests very well. This option	695	Most name servers do not handle many parallel requests very well. This
559	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	696	option limits the number of outstanding requests to C<$integer>
560	if you request more than this many requests, then the additional requests will be queued	697	(default: C<10>), that means if you request more than this many requests,
561	until some other requests have been resolved.	698	then the additional requests will be queued until some other requests have
		699	been resolved.
		700
		701	=item reuse => $seconds
		702
		703	The number of seconds (default: C<300>) that a query id cannot be re-used
		704	after a timeout. If there was no time-out then query ids can be reused
		705	immediately.
562		706
563	=back	707	=back
564		708
565	=cut	709	=cut
566		710
567	sub new {	711	sub new {
568	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
569		713
570	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
571	or Carp::croak "socket: $!";
572
573	AnyEvent::Util::fh_nonblocking $fh, 1;
574
575	my $self = bless {	714	my $self = bless {
576	server => [v127.0.0.1],	715	server => [],
577	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
578	search => [],	717	search => [],
579	ndots => 1,	718	ndots => 1,
580	max_outstanding => 10,	719	max_outstanding => 10,
581	reuse => 300, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
582	%arg,	721	%arg,
583	fh => $fh,
584	reuse_q => [],	722	reuse_q => [],
585	}, $class;	723	}, $class;
586		724
587	# search should default to gethostname's domain	725	# search should default to gethostname's domain
588	# but perl lacks a good posix module	726	# but perl lacks a good posix module
589		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
590	Scalar::Util::weaken (my $wself = $self);	732	Scalar::Util::weaken (my $wself = $self);
		733
		734	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		735	++$got_socket;
		736
		737	AnyEvent::Util::fh_nonblocking $fh4, 1;
		738	$self->{fh4} = $fh4;
591	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	739	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		740	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		741	$wself->_recv ($pkt, $peer);
		742	}
		743	});
		744	}
		745
		746	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		747	++$got_socket;
		748
		749	$self->{fh6} = $fh6;
		750	AnyEvent::Util::fh_nonblocking $fh6, 1;
		751	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		752	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		753	$wself->_recv ($pkt, $peer);
		754	}
		755	});
		756	}
		757
		758	$got_socket
		759	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
592		760
593	$self->_compile;	761	$self->_compile;
594		762
595	$self	763	$self
596	}	764	}
597		765
598	=item $resolver->parse_resolv_conv ($string)	766	=item $resolver->parse_resolv_conv ($string)
599		767
600	Parses the given string a sif it were a F<resolv.conf> file. The following	768	Parses the given string as if it were a F<resolv.conf> file. The following
601	directives are supported:	769	directives are supported (but not necessarily implemented).
602		770
603	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	771	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
604	C<options> (C<timeout>, C<attempts>, C<ndots>).	772	C<options> (C<timeout>, C<attempts>, C<ndots>).
605		773
606	Everything else is silently ignored.	774	Everything else is silently ignored.
…		…
618	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
619	if (/^\s*#/) {	787	if (/^\s*#/) {
620	# comment	788	# comment
621	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
622	my $ip = $1;	790	my $ip = $1;
623	if (AnyEvent::Util::dotted_quad $ip) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
624	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	792	push @{ $self->{server} }, $ipn;
625	} else {	793	} else {
626	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
627	}	795	}
628	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
629	$self->{search} = [$1];	797	$self->{search} = [$1];
…		…
650	if $attempts;	818	if $attempts;
651		819
652	$self->_compile;	820	$self->_compile;
653	}	821	}
654		822
655	=item $resolver->load_resolv_conf	823	=item $resolver->os_config
656		824
657	Tries to load and parse F</etc/resolv.conf>. If there will ever be windows	825	Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various
658	support, then this function will do the right thing under windows, too.	826	egregious hacks on windows to force the DNS servers and searchlist out of the system.
659		827
660	=cut	828	=cut
661		829
662	sub load_resolv_conf {	830	sub os_config {
663	my ($self) = @_;	831	my ($self) = @_;
664		832
		833	$self->{server} = [];
		834	$self->{search} = [];
		835
		836	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		837	no strict 'refs';
		838
		839	# there are many options to find the current nameservers etc. on windows
		840	# all of them don't work consistently:
		841	# - the registry thing needs separate code on win32 native vs. cygwin
		842	# - the registry layout differs between windows versions
		843	# - calling windows api functions doesn't work on cygwin
		844	# - ipconfig uses locale-specific messages
		845
		846	# we use ipconfig parsing because, despite all its brokenness,
		847	# it seems most stable in practise.
		848	# for good measure, we append a fallback nameserver to our list.
		849
		850	if (open my $fh, "ipconfig /all \|") {
		851	# parsing strategy: we go through the output and look for
		852	# :-lines with DNS in them. everything in those is regarded as
		853	# either a nameserver (if it parses as an ip address), or a suffix
		854	# (all else).
		855
		856	my $dns;
		857	while (<$fh>) {
		858	if (s/^\s.\bdns\b.://i) {
		859	$dns = 1;
		860	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		861	$dns = 0;
		862	}
		863	if ($dns && /^\s(\S+)\s$/) {
		864	my $s = $1;
		865	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		866	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		867	push @{ $self->{server} }, $ipn;
		868	} else {
		869	push @{ $self->{search} }, $s;
		870	}
		871	}
		872	}
		873
		874	# always add one fallback server
		875	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
		876
		877	$self->_compile;
		878	}
		879	} else {
		880	# try resolv.conf everywhere
		881
665	open my $fh, "</etc/resolv.conf"	882	if (open my $fh, "</etc/resolv.conf") {
666	or return;
667
668	local $/;	883	local $/;
669	$self->parse_resolv_conf (<$fh>);	884	$self->parse_resolv_conf (<$fh>);
		885	}
		886	}
		887	}
		888
		889	=item $resolver->timeout ($timeout, ...)
		890
		891	Sets the timeout values. See the C<timeout> constructor argument (and note
		892	that this method uses the values itself, not an array-reference).
		893
		894	=cut
		895
		896	sub timeout {
		897	my ($self, @timeout) = @_;
		898
		899	$self->{timeout} = \@timeout;
		900	$self->_compile;
		901	}
		902
		903	=item $resolver->max_outstanding ($nrequests)
		904
		905	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		906	C<max_outstanding> constructor argument.
		907
		908	=cut
		909
		910	sub max_outstanding {
		911	my ($self, $max) = @_;
		912
		913	$self->{max_outstanding} = $max;
		914	$self->_scheduler;
670	}	915	}
671		916
672	sub _compile {	917	sub _compile {
673	my $self = shift;	918	my $self = shift;
		919
		920	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		921	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		922
		923	unless (@{ $self->{server} }) {
		924	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		925	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		926	}
674		927
675	my @retry;	928	my @retry;
676		929
677	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
678	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
696	$NOW = time;	949	$NOW = time;
697	$id->[1]->($res);	950	$id->[1]->($res);
698	}	951	}
699		952
700	sub _recv {	953	sub _recv {
701	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
702		955
703	while (my $peer = recv $self->{fh}, my $res, 4000, 0) {	956	# we ignore errors (often one gets port unreachable, but there is
		957	# no good way to take advantage of that.
		958
704	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
705		960
706	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
707		962
708	$self->_feed ($res);	963	$self->_feed ($pkt);
709	}
710	}	964	}
711		965
		966	sub _free_id {
		967	my ($self, $id, $timeout) = @_;
		968
		969	if ($timeout) {
		970	# we need to block the id for a while
		971	$self->{id}{$id} = 1;
		972	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		973	} else {
		974	# we can quickly recycle the id
		975	delete $self->{id}{$id};
		976	}
		977
		978	--$self->{outstanding};
		979	$self->_scheduler;
		980	}
		981
		982	# execute a single request, involves sending it with timeouts to multiple servers
712	sub _exec {	983	sub _exec {
713	my ($self, $req, $retry) = @_;	984	my ($self, $req) = @_;
714		985
		986	my $retry; # of retries
		987	my $do_retry;
		988
		989	$do_retry = sub {
715	if (my $retry_cfg = $self->{retry}[$retry]) {	990	my $retry_cfg = $self->{retry}[$retry++]
		991	or do {
		992	# failure
		993	$self->_free_id ($req->[2], $retry > 1);
		994	undef $do_retry; return $req->[1]->();
		995	};
		996
716	my ($server, $timeout) = @$retry_cfg;	997	my ($server, $timeout) = @$retry_cfg;
717		998
718	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
719	$NOW = time;	1000	$NOW = time;
720		1001
721	# timeout, try next	1002	# timeout, try next
722	$self->_exec ($req, $retry + 1);	1003	&$do_retry if $do_retry;
723	}), sub {	1004	}), sub {
724	my ($res) = @_;	1005	my ($res) = @_;
725		1006
726	if ($res->{tc}) {	1007	if ($res->{tc}) {
727	# success, but truncated, so use tcp	1008	# success, but truncated, so use tcp
728	AnyEvent::Util::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1009	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1010	return unless $do_retry; # some other request could have invalidated us already
		1011
729	my ($fh) = @_	1012	my ($fh) = @_
730	or return $self->_exec ($req, $retry + 1);	1013	or return &$do_retry;
731		1014
732	my $handle = new AnyEvent::Handle	1015	my $handle; $handle = new AnyEvent::Handle
733	fh => $fh,	1016	fh => $fh,
		1017	timeout => $timeout,
734	on_error => sub {	1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
735	# failure, try next	1021	# failure, try next
736	$self->_exec ($req, $retry + 1);	1022	&$do_retry;
737	};	1023	};
738		1024
739	$handle->push_write (pack "n/a", $req->[0]);	1025	$handle->push_write (pack "n/a", $req->[0]);
740	$handle->push_read_chunk (2, sub {	1026	$handle->push_read (chunk => 2, sub {
741	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
742	$self->_feed ($_[1]);	1029	$self->_feed ($_[1]);
743	});	1030	});
744	});	1031	});
745	shutdown $fh, 1;
746		1032
747	}, sub { $timeout };	1033	}, sub { $timeout });
748		1034
749	} else {	1035	} else {
750	# success	1036	# success
751	$self->{id}{$req->[2]} = 1;	1037	$self->_free_id ($req->[2], $retry > 1);
752	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1038	undef $do_retry; return $req->[1]->($res);
753	--$self->{outstanding};
754	$self->_scheduler;
755
756	$req->[1]->($res);
757	}	1039	}
758	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
759		1043
760	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
761	} else {	1045	? $self->{fh4} : $self->{fh6}
762	# failure	1046	or return &$do_retry;
763	$self->{id}{$req->[2]} = 1;
764	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
765	--$self->{outstanding};
766	$self->_scheduler;
767		1047
768	$req->[1]->();	1048	send $fh, $req->[0], 0, $sa;
769	}	1049	};
		1050
		1051	&$do_retry;
770	}	1052	}
771		1053
772	sub _scheduler {	1054	sub _scheduler {
773	my ($self) = @_;	1055	my ($self) = @_;
774		1056
		1057	no strict 'refs';
		1058
775	$NOW = time;	1059	$NOW = time;
776		1060
777	# first clear id reuse queue	1061	# first clear id reuse queue
778	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
779	while @{ $self->{reuse_q} } && $self->{reuse_q}[0] <= $NOW;	1063	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;
780		1064
781	while ($self->{outstanding} < $self->{max_outstanding}) {	1065	while ($self->{outstanding} < $self->{max_outstanding}) {
782	my $req = shift @{ $self->{queue} }	1066
		1067	if (@{ $self->{reuse_q} } >= 30000) {
		1068	# we ran out of ID's, wait a bit
		1069	$self->{reuse_to} \|\|= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub {
		1070	delete $self->{reuse_to};
		1071	$self->_scheduler;
		1072	});
783	or last;	1073	last;
784
785	while () {
786	$req->[2] = int rand 65536;
787	last unless exists $self->{id}{$req->[2]};
788	}	1074	}
789		1075
		1076	if (my $req = shift @{ $self->{queue} }) {
		1077	# found a request in the queue, execute it
		1078	while () {
		1079	$req->[2] = int rand 65536;
		1080	last unless exists $self->{id}{$req->[2]};
		1081	}
		1082
		1083	++$self->{outstanding};
790	$self->{id}{$req->[2]} = 1;	1084	$self->{id}{$req->[2]} = 1;
791	substr $req->[0], 0, 2, pack "n", $req->[2];	1085	substr $req->[0], 0, 2, pack "n", $req->[2];
792		1086
793	++$self->{outstanding};
794	$self->_exec ($req, 0);	1087	$self->_exec ($req);
		1088
		1089	} elsif (my $cb = shift @{ $self->{wait} }) {
		1090	# found a wait_for_slot callback, call that one first
		1091	$cb->($self);
		1092
		1093	} else {
		1094	# nothing to do, just exit
		1095	last;
		1096	}
795	}	1097	}
796	}	1098	}
797		1099
798	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
799		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
800	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
801	C<dns_pack>) to the configured nameservers including	1105	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1106	response. It handles timeouts, retries and automatically falls back to
		1107	virtual circuit mode (TCP) when it receives a truncated reply.
		1108
802	retries. Calls the callback with the decoded response packet if a reply	1109	Calls the callback with the decoded response packet if a reply was
803	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
804		1111
805	=cut	1112	=cut
806		1113
807	sub request($$) {	1114	sub request($$) {
808	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
…		…
811	$self->_scheduler;	1118	$self->_scheduler;
812	}	1119	}
813		1120
814	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))
815		1122
816	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1123	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
817	qtype of "*" is supported and means "any").	1124
		1125	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1126	a lowercase name (you have to look at the source to see which aliases are
		1127	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1128	more are known to this module). A C<$qtype> of "*" is supported and means
		1129	"any" record type.
818		1130
819	The callback will be invoked with a list of matching result records or	1131	The callback will be invoked with a list of matching result records or
820	none on any error or if the name could not be found.	1132	none on any error or if the name could not be found.
821		1133
822	CNAME chains (although illegal) are followed up to a length of 8.	1134	CNAME chains (although illegal) are followed up to a length of 10.
823		1135
		1136	The callback will be invoked with an result code in string form (noerror,
		1137	formerr, servfail, nxdomain, notimp, refused and so on), or numerical
		1138	form if the result code is not supported. The remaining arguments are
		1139	arraryefs of the form C<[$name, $type, $class, @data>], where C<$name> is
		1140	the domain name, C<$type> a type string or number, C<$class> a class name
		1141	and @data is resource-record-dependent data. For C<a> records, this will
		1142	be the textual IPv4 addresses, for C<ns> or C<cname> records this will be
		1143	a domain name, for C<txt> records these are all the strings and so on.
		1144
		1145	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1146	decoded. All resource records not known to this module will have
		1147	the raw C<rdata> field as fourth entry.
		1148
824	Note that this resolver is just a stub resolver: it requires a nameserver	1149	Note that this resolver is just a stub resolver: it requires a name server
825	supporting recursive queries, will not do any recursive queries itself and	1150	supporting recursive queries, will not do any recursive queries itself and
826	is not secure when used against an untrusted name server.	1151	is not secure when used against an untrusted name server.
827		1152
828	The following options are supported:	1153	The following options are supported:
829		1154
…		…
831		1156
832	=item search => [$suffix...]	1157	=item search => [$suffix...]
833		1158
834	Use the given search list (which might be empty), by appending each one	1159	Use the given search list (which might be empty), by appending each one
835	in turn to the C<$qname>. If this option is missing then the configured	1160	in turn to the C<$qname>. If this option is missing then the configured
836	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1161	C<ndots> and C<search> values define its value (depending on C<ndots>, the
837	then the searchlist will be ignored.	1162	empty suffix will be prepended or appended to that C<search> value). If
		1163	the C<$qname> ends in a dot, then the searchlist will be ignored.
838		1164
839	=item accept => [$type...]	1165	=item accept => [$type...]
840		1166
841	Lists the acceptable result types: only result types in this set will be	1167	Lists the acceptable result types: only result types in this set will be
842	accepted and returned. The default includes the C<$qtype> and nothing	1168	accepted and returned. The default includes the C<$qtype> and nothing
843	else.	1169	else. If this list includes C<cname>, then CNAME-chains will not be
		1170	followed (because you asked for the CNAME record).
844		1171
845	=item class => "class"	1172	=item class => "class"
846		1173
847	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1174	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
848	hesiod are the only ones making sense). The default is "in", of course.	1175	hesiod are the only ones making sense). The default is "in", of course.
849		1176
850	=back	1177	=back
851		1178
852	Examples:	1179	Examples:
853		1180
854	$res->resolve ("ruth.plan9.de", "a", sub {	1181	# full example, you can paste this into perl:
855	warn Dumper [@_];	1182	use Data::Dumper;
856	});	1183	use AnyEvent::DNS;
		1184	AnyEvent::DNS::resolver->resolve (
		1185	"google.com", "*", my $cv = AnyEvent->condvar);
		1186	warn Dumper [$cv->recv];
857		1187
		1188	# shortened result:
858	[	1189	# [
		1190	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1191	# 2008052701, 7200, 1800, 1209600, 300 ],
859	[	1192	# [
860	'ruth.schmorp.de',	1193	# 'google.com', 'txt', 'in',
861	'a',	1194	# 'v=spf1 include:_netblocks.google.com ~all'
862	'in',	1195	# ],
863	'129.13.162.95'	1196	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1197	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1198	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
864	]	1199	# ]
		1200
		1201	# resolve a records:
		1202	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1203
		1204	# result:
		1205	# [
		1206	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
865	]	1207	# ]
866		1208
		1209	# resolve any records, but return only a and aaaa records:
867	$res->resolve ("test1.laendle", "*",	1210	$res->resolve ("test1.laendle", "*",
868	accept => ["a", "aaaa"],	1211	accept => ["a", "aaaa"],
869	sub {	1212	sub {
870	warn Dumper [@_];	1213	warn Dumper [@_];
871	}	1214	}
872	);	1215	);
873		1216
874	[	1217	# result:
875	[	1218	# [
876	'test1.laendle',	1219	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
877	'a',	1220	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
878	'in',
879	'10.0.0.255'
880	],
881	[
882	'test1.laendle',
883	'aaaa',
884	'in',
885	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
886	]	1221	# ]
887	]
888		1222
889	=cut	1223	=cut
890		1224
891	sub resolve($%) {	1225	sub resolve($%) {
892	my $cb = pop;	1226	my $cb = pop;
…		…
905	my %atype = $opt{accept}	1239	my %atype = $opt{accept}
906	? map +($_ => 1), @{ $opt{accept} }	1240	? map +($_ => 1), @{ $opt{accept} }
907	: ($qtype => 1);	1241	: ($qtype => 1);
908		1242
909	# advance in searchlist	1243	# advance in searchlist
910	my $do_search; $do_search = sub {	1244	my ($do_search, $do_req);
		1245
		1246	$do_search = sub {
911	@search	1247	@search
912	or return $cb->();	1248	or (undef $do_search), (undef $do_req), return $cb->();
913		1249
914	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1250	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
915	my $depth = 2;	1251	my $depth = 10;
916		1252
917	# advance in cname-chain	1253	# advance in cname-chain
918	my $do_req; $do_req = sub {	1254	$do_req = sub {
919	$self->request ({	1255	$self->request ({
920	rd => 1,	1256	rd => 1,
921	qd => [[$name, $qtype, $class]],	1257	qd => [[$name, $qtype, $class]],
922	}, sub {	1258	}, sub {
923	my ($res) = @_	1259	my ($res) = @_
…		…
927		1263
928	while () {	1264	while () {
929	# results found?	1265	# results found?
930	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1266	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
931		1267
932	return $cb->(@rr)	1268	(undef $do_search), (undef $do_req), return $cb->(@rr)
933	if @rr;	1269	if @rr;
934		1270
935	# see if there is a cname we can follow	1271	# see if there is a cname we can follow
936	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1272	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
937		1273
…		…
958	};	1294	};
959		1295
960	$do_search->();	1296	$do_search->();
961	}	1297	}
962		1298
		1299	=item $resolver->wait_for_slot ($cb->($resolver))
		1300
		1301	Wait until a free request slot is available and call the callback with the
		1302	resolver object.
		1303
		1304	A request slot is used each time a request is actually sent to the
		1305	nameservers: There are never more than C<max_outstanding> of them.
		1306
		1307	Although you can submit more requests (they will simply be queued until
		1308	a request slot becomes available), sometimes, usually for rate-limiting
		1309	purposes, it is useful to instead wait for a slot before generating the
		1310	request (or simply to know when the request load is low enough so one can
		1311	submit requests again).
		1312
		1313	This is what this method does: The callback will be called when submitting
		1314	a DNS request will not result in that request being queued. The callback
		1315	may or may not generate any requests in response.
		1316
		1317	Note that the callback will only be invoked when the request queue is
		1318	empty, so this does not play well if somebody else keeps the request queue
		1319	full at all times.
		1320
		1321	=cut
		1322
		1323	sub wait_for_slot {
		1324	my ($self, $cb) = @_;
		1325
		1326	push @{ $self->{wait} }, $cb;
		1327	$self->_scheduler;
		1328	}
		1329
		1330	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
		1331
963	1;	1332	1;
964		1333
965	=back	1334	=back
966		1335
967	=head1 AUTHOR	1336	=head1 AUTHOR
968		1337
969	Marc Lehmann <schmorp@schmorp.de>	1338	Marc Lehmann <schmorp@schmorp.de>
970	http://home.schmorp.de/	1339	http://home.schmorp.de/
971		1340
972	=cut	1341	=cut
973		1342

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.7 by root, Fri May 23 05:30:59 2008 UTC vs. Revision 1.75 by root, Thu Aug 21 23:48:35 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.7 by root, Fri May 23 05:30:59 2008 UTC vs.
Revision 1.75 by root, Thu Aug 21 23:48:35 2008 UTC