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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.10 by root, Fri May 23 06:03:51 2008 UTC vs.
Revision 1.103 by root, Thu Jul 9 08:31:16 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
		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 Carp ();
		35	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		36
25	use AnyEvent::Util ();	37	use AnyEvent ();
26	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 = 4.81;
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
166	=cut	291	=item $AnyEvent::DNS::EDNS0
167		292
168	sub EDNS0 () { 0 } # set to 1 to enable (partial) edns0	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
		298	=cut
		299
		300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0}*1; # set to 1 to enable (partial) edns0
169		301
170	our %opcode_id = (	302	our %opcode_id = (
171	query => 0,	303	query => 0,
172	iquery => 1,	304	iquery => 1,
173	status => 2,	305	status => 2,
…		…
219	minfo => 14,	351	minfo => 14,
220	mx => 15,	352	mx => 15,
221	txt => 16,	353	txt => 16,
222	aaaa => 28,	354	aaaa => 28,
223	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
		357	dname => 39, # rfc2672
224	opt => 41,	358	opt => 41,
225	spf => 99,	359	spf => 99,
226	tkey => 249,	360	tkey => 249,
227	tsig => 250,	361	tsig => 250,
228	ixfr => 251,	362	ixfr => 251,
…		…
241	"*" => 255,	375	"*" => 255,
242	);	376	);
243		377
244	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
245		379
246	# names MUST have a trailing dot
247	sub _enc_qname($) {	380	sub _enc_name($) {
248	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
249	}	382	}
250		383
251	sub _enc_qd() {	384	sub _enc_qd() {
252	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
253	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
254	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
255	}	388	}
256		389
257	sub _enc_rr() {	390	sub _enc_rr() {
258	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
259	}	392	}
260		393
261	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
262		395
263	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
264	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
265		398
266	Resource records are not yet encodable.	399	Resource records are not yet encodable.
267		400
268	Examples:	401	Examples:
269		402
270	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
271	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
272		405
273	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
274		407
275	{	408	{
276	id => 10000,	409	id => 10000,
277	op => "query",	410	op => "query",
278	rc => "nxdomain",	411	rc => "nxdomain",
279		412
280	# flags	413	# flags
281	qr => 1,	414	qr => 1,
282	aa => 0,	415	aa => 0,
283	tc => 0,	416	tc => 0,
284	rd => 0,	417	rd => 0,
285	ra => 0,	418	ra => 0,
286	ad => 0,	419	ad => 0,
287	cd => 0,	420	cd => 0,
288		421
289	qd => [@rr], # query section	422	qd => [@rr], # query section
290	an => [@rr], # answer section	423	an => [@rr], # answer section
291	ns => [@rr], # authority section	424	ns => [@rr], # authority section
292	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
293	}	426	}
294		427
295	=cut	428	=cut
296		429
297	sub dns_pack($) {	430	sub dns_pack($) {
298	my ($req) = @_;	431	my ($req) = @_;
…		…
311	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
312		445
313	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
314	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
315	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
316	EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
317		450
318	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
319	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
320	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
321	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
322		455
323	(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
324	}	457	}
325		458
326	our $ofs;	459	our $ofs;
327	our $pkt;	460	our $pkt;
328		461
329	# bitches	462	# bitches
330	sub _dec_qname {	463	sub _dec_name {
331	my @res;	464	my @res;
332	my $redir;	465	my $redir;
333	my $ptr = $ofs;	466	my $ptr = $ofs;
334	my $cnt;	467	my $cnt;
335		468
336	while () {	469	while () {
337	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
338		471
339	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
340		473
341	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
342	$ptr++;	475	$ptr++;
343	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
344	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
345	} elsif ($len) {	478	} elsif ($len) {
346	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
351	}	484	}
352	}	485	}
353	}	486	}
354		487
355	sub _dec_qd {	488	sub _dec_qd {
356	my $qname = _dec_qname;	489	my $qname = _dec_name;
357	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
358	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
359	}	492	}
360		493
361	our %dec_rr = (	494	our %dec_rr = (
362	1 => sub { Socket::inet_ntoa $_ }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
363	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
364	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
365	6 => sub {	498	6 => sub {
366	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
367	my $mname = _dec_qname;	500	my $mname = _dec_name;
368	my $rname = _dec_qname;	501	my $rname = _dec_name;
369	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
370	}, # soa	503	}, # soa
371	11 => sub { ((Socket::inet_aton substr $_, 0, 4), unpack "C a*", substr $_, 4) }, # wks	504	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
372	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
373	13 => sub { unpack "C/a C/a", $_ }, # hinfo	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
374	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
375	16 => sub { unpack "(C/a)*", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
376	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	509	28 => sub { AnyEvent::Socket::format_ipv6 ($_) }, # aaaa
377	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
378	99 => sub { unpack "(C/a)*", $_ }, # spf	518	99 => sub { unpack "(C/a)", $_ }, # spf
379	);	519	);
380		520
381	sub _dec_rr {	521	sub _dec_rr {
382	my $qname = _dec_qname;	522	my $name = _dec_name;
383		523
384	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;
385	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
386		526
387	[	527	[
388	$qname,	528	$name,
389	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
390	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
391	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
392	]	532	]
393	}	533	}
…		…
396		536
397	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
398		538
399	Examples:	539	Examples:
400		540
401	# a non-successful reply	541	# an unsuccessful reply
402	{	542	{
403	'qd' => [	543	'qd' => [
404	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
405	],	545	],
406	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
407	'ar' => [],	547	'ar' => [],
408	'ns' => [	548	'ns' => [
409	[	549	[
410	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
411	'soa',	551	'soa',
412	'in',	552	'in',
413	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
414	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
415	2008052201,	555	2008052201, 10800, 1800, 2592000, 86400
416	10800,
417	1800,
418	2592000,
419	86400
420	]	556	]
421	],	557	],
422	'tc' => '',	558	'tc' => '',
423	'ra' => 1,	559	'ra' => 1,
424	'qr' => 1,	560	'qr' => 1,
425	'id' => 45915,	561	'id' => 45915,
426	'aa' => '',	562	'aa' => '',
427	'an' => [],	563	'an' => [],
428	'rd' => 1,	564	'rd' => 1,
429	'op' => 'query'	565	'op' => 'query'
430	}	566	}
431		567
432	# a successful reply	568	# a successful reply
433		569
434	{	570	{
435	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
436	'rc' => 0,	572	'rc' => 0,
437	'ar' => [	573	'ar' => [
438	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
439	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
440	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
441	],	577	],
442	'ns' => [	578	'ns' => [
443	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
444	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
445	],	581	],
446	'tc' => '',	582	'tc' => '',
447	'ra' => 1,	583	'ra' => 1,
448	'qr' => 1,	584	'qr' => 1,
449	'id' => 64265,	585	'id' => 64265,
450	'aa' => '',	586	'aa' => '',
451	'an' => [	587	'an' => [
452	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
453	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
454	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
455	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
456	],	592	],
457	'rd' => 1,	593	'rd' => 1,
458	'op' => 0	594	'op' => 0
459	}	595	}
460		596
461	=cut	597	=cut
462		598
463	sub dns_unpack($) {	599	sub dns_unpack($) {
464	local $pkt = shift;	600	local $pkt = shift;
…		…
490		626
491	=back	627	=back
492		628
493	=head2 THE AnyEvent::DNS RESOLVER CLASS	629	=head2 THE AnyEvent::DNS RESOLVER CLASS
494		630
495	This is the class which deos the actual protocol work.	631	This is the class which does the actual protocol work.
496		632
497	=over 4	633	=over 4
498		634
499	=cut	635	=cut
500		636
…		…
513	calls.	649	calls.
514		650
515	Unless you have special needs, prefer this function over creating your own	651	Unless you have special needs, prefer this function over creating your own
516	resolver object.	652	resolver object.
517		653
		654	The resolver is created with the following parameters:
		655
		656	untaint enabled
		657	max_outstanding $ENV{PERL_ANYEVENT_MAX_OUTSTANDING_DNS}
		658
		659	C<os_config> will be used for OS-specific configuration, unless
		660	C<$ENV{PERL_ANYEVENT_RESOLV_CONF}> is specified, in which case that file
		661	gets parsed.
		662
518	=cut	663	=cut
519		664
520	our $RESOLVER;	665	our $RESOLVER;
521		666
522	sub resolver() {	667	sub resolver() {
523	$RESOLVER \|\| do {	668	$RESOLVER \|\| do {
524	$RESOLVER = new AnyEvent::DNS;	669	$RESOLVER = new AnyEvent::DNS
		670	untaint => 1,
		671	exists $ENV{PERL_ANYEVENT_MAX_OUTSTANDING_DNS}
		672	? (max_outstanding => $ENV{PERL_ANYEVENT_MAX_OUTSTANDING_DNS}*1 \|\| 1) : (),
		673	;
		674
		675	exists $ENV{PERL_ANYEVENT_RESOLV_CONF}
		676	? length $ENV{PERL_ANYEVENT_RESOLV_CONF} && $RESOLVER->_parse_resolv_conf_file ($ENV{PERL_ANYEVENT_RESOLV_CONF})
525	$RESOLVER->load_resolv_conf;	677	: $RESOLVER->os_config;
		678
526	$RESOLVER	679	$RESOLVER
527	}	680	}
528	}	681	}
529		682
530	=item $resolver = new AnyEvent::DNS key => value...	683	=item $resolver = new AnyEvent::DNS key => value...
…		…
535		688
536	=over 4	689	=over 4
537		690
538	=item server => [...]	691	=item server => [...]
539		692
540	A list of server addressses (default C<v127.0.0.1>) in network format (4	693	A list of server addresses (default: C<v127.0.0.1>) in network format
541	octets for IPv4, 16 octets for IPv6 - not yet supported).	694	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		695	IPv6 are supported).
542		696
543	=item timeout => [...]	697	=item timeout => [...]
544		698
545	A list of timeouts to use (also determines the number of retries). To make	699	A list of timeouts to use (also determines the number of retries). To make
546	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	700	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
555	The number of dots (default: C<1>) that a name must have so that the resolver	709	The number of dots (default: C<1>) that a name must have so that the resolver
556	tries to resolve the name without any suffixes first.	710	tries to resolve the name without any suffixes first.
557		711
558	=item max_outstanding => $integer	712	=item max_outstanding => $integer
559		713
560	Most name servers do not handle many parallel requests very well. This option	714	Most name servers do not handle many parallel requests very well. This
561	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	715	option limits the number of outstanding requests to C<$integer>
562	if you request more than this many requests, then the additional requests will be queued	716	(default: C<10>), that means if you request more than this many requests,
563	until some other requests have been resolved.	717	then the additional requests will be queued until some other requests have
		718	been resolved.
		719
		720	=item reuse => $seconds
		721
		722	The number of seconds (default: C<300>) that a query id cannot be re-used
		723	after a timeout. If there was no time-out then query ids can be reused
		724	immediately.
		725
		726	=item untaint => $boolean
		727
		728	When true, then the resolver will automatically untaint results, and might
		729	also ignore certain environment variables.
564		730
565	=back	731	=back
566		732
567	=cut	733	=cut
568		734
569	sub new {	735	sub new {
570	my ($class, %arg) = @_;	736	my ($class, %arg) = @_;
571		737
572	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
573	or Carp::croak "socket: $!";
574
575	AnyEvent::Util::fh_nonblocking $fh, 1;
576
577	my $self = bless {	738	my $self = bless {
578	server => [v127.0.0.1],	739	server => [],
579	timeout => [2, 5, 5],	740	timeout => [2, 5, 5],
580	search => [],	741	search => [],
581	ndots => 1,	742	ndots => 1,
582	max_outstanding => 10,	743	max_outstanding => 10,
583	reuse => 300, # reuse id's after 5 minutes only, if possible	744	reuse => 300,
584	%arg,	745	%arg,
585	fh => $fh,
586	reuse_q => [],	746	reuse_q => [],
587	}, $class;	747	}, $class;
588		748
589	# search should default to gethostname's domain	749	# search should default to gethostname's domain
590	# but perl lacks a good posix module	750	# but perl lacks a good posix module
591		751
		752	# try to create an ipv4 and an ipv6 socket
		753	# only fail when we cannot create either
		754	my $got_socket;
		755
592	Scalar::Util::weaken (my $wself = $self);	756	Scalar::Util::weaken (my $wself = $self);
		757
		758	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		759	++$got_socket;
		760
		761	AnyEvent::Util::fh_nonblocking $fh4, 1;
		762	$self->{fh4} = $fh4;
593	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	763	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		764	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		765	$wself->_recv ($pkt, $peer);
		766	}
		767	});
		768	}
		769
		770	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		771	++$got_socket;
		772
		773	$self->{fh6} = $fh6;
		774	AnyEvent::Util::fh_nonblocking $fh6, 1;
		775	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		776	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		777	$wself->_recv ($pkt, $peer);
		778	}
		779	});
		780	}
		781
		782	$got_socket
		783	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
594		784
595	$self->_compile;	785	$self->_compile;
596		786
597	$self	787	$self
598	}	788	}
599		789
600	=item $resolver->parse_resolv_conv ($string)	790	=item $resolver->parse_resolv_conf ($string)
601		791
602	Parses the given string a sif it were a F<resolv.conf> file. The following	792	Parses the given string as if it were a F<resolv.conf> file. The following
603	directives are supported:	793	directives are supported (but not necessarily implemented).
604		794
605	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	795	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
606	C<options> (C<timeout>, C<attempts>, C<ndots>).	796	C<options> (C<timeout>, C<attempts>, C<ndots>).
607		797
608	Everything else is silently ignored.	798	Everything else is silently ignored.
…		…
620	for (split /\n/, $resolvconf) {	810	for (split /\n/, $resolvconf) {
621	if (/^\s*#/) {	811	if (/^\s*#/) {
622	# comment	812	# comment
623	} elsif (/^\snameserver\s+(\S+)\s$/i) {	813	} elsif (/^\snameserver\s+(\S+)\s$/i) {
624	my $ip = $1;	814	my $ip = $1;
625	if (AnyEvent::Util::dotted_quad $ip) {	815	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
626	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	816	push @{ $self->{server} }, $ipn;
627	} else {	817	} else {
628	warn "nameserver $ip invalid and ignored\n";	818	warn "nameserver $ip invalid and ignored\n";
629	}	819	}
630	} elsif (/^\sdomain\s+(\S)\s+$/i) {	820	} elsif (/^\sdomain\s+(\S)\s+$/i) {
631	$self->{search} = [$1];	821	$self->{search} = [$1];
…		…
652	if $attempts;	842	if $attempts;
653		843
654	$self->_compile;	844	$self->_compile;
655	}	845	}
656		846
657	=item $resolver->load_resolv_conf	847	sub _parse_resolv_conf_file {
		848	my ($self, $resolv_conf) = @_;
658		849
659	Tries to load and parse F</etc/resolv.conf>. If there will ever be windows
660	support, then this function will do the right thing under windows, too.
661
662	=cut
663
664	sub load_resolv_conf {
665	my ($self) = @_;
666
667	open my $fh, "</etc/resolv.conf"	850	open my $fh, "<:perlio", $resolv_conf
668	or return;	851	or Carp::croak "$resolv_conf: $!";
669		852
670	local $/;	853	local $/;
671	$self->parse_resolv_conf (<$fh>);	854	$self->parse_resolv_conf (<$fh>);
672	}	855	}
673		856
		857	=item $resolver->os_config
		858
		859	Tries so load and parse F</etc/resolv.conf> on portable operating
		860	systems. Tries various egregious hacks on windows to force the DNS servers
		861	and searchlist out of the system.
		862
		863	=cut
		864
		865	sub os_config {
		866	my ($self) = @_;
		867
		868	$self->{server} = [];
		869	$self->{search} = [];
		870
		871	if ((AnyEvent::WIN32 \|\| $^O =~ /cygwin/i)) {
		872	no strict 'refs';
		873
		874	# there are many options to find the current nameservers etc. on windows
		875	# all of them don't work consistently:
		876	# - the registry thing needs separate code on win32 native vs. cygwin
		877	# - the registry layout differs between windows versions
		878	# - calling windows api functions doesn't work on cygwin
		879	# - ipconfig uses locale-specific messages
		880
		881	# we use ipconfig parsing because, despite all its brokenness,
		882	# it seems most stable in practise.
		883	# for good measure, we append a fallback nameserver to our list.
		884
		885	if (open my $fh, "ipconfig /all \|") {
		886	# parsing strategy: we go through the output and look for
		887	# :-lines with DNS in them. everything in those is regarded as
		888	# either a nameserver (if it parses as an ip address), or a suffix
		889	# (all else).
		890
		891	my $dns;
		892	while (<$fh>) {
		893	if (s/^\s.\bdns\b.://i) {
		894	$dns = 1;
		895	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		896	$dns = 0;
		897	}
		898	if ($dns && /^\s(\S+)\s$/) {
		899	my $s = $1;
		900	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		901	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		902	push @{ $self->{server} }, $ipn;
		903	} else {
		904	push @{ $self->{search} }, $s;
		905	}
		906	}
		907	}
		908
		909	# always add one fallback server
		910	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
		911
		912	$self->_compile;
		913	}
		914	} else {
		915	# try resolv.conf everywhere else
		916
		917	$self->_parse_resolv_conf_file ("/etc/resolv.conf")
		918	if -e "/etc/resolv.conf";
		919	}
		920	}
		921
		922	=item $resolver->timeout ($timeout, ...)
		923
		924	Sets the timeout values. See the C<timeout> constructor argument (and note
		925	that this method uses the values itself, not an array-reference).
		926
		927	=cut
		928
		929	sub timeout {
		930	my ($self, @timeout) = @_;
		931
		932	$self->{timeout} = \@timeout;
		933	$self->_compile;
		934	}
		935
		936	=item $resolver->max_outstanding ($nrequests)
		937
		938	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		939	C<max_outstanding> constructor argument.
		940
		941	=cut
		942
		943	sub max_outstanding {
		944	my ($self, $max) = @_;
		945
		946	$self->{max_outstanding} = $max;
		947	$self->_scheduler;
		948	}
		949
674	sub _compile {	950	sub _compile {
675	my $self = shift;	951	my $self = shift;
		952
		953	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		954	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		955
		956	unless (@{ $self->{server} }) {
		957	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		958	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		959	}
676		960
677	my @retry;	961	my @retry;
678		962
679	for my $timeout (@{ $self->{timeout} }) {	963	for my $timeout (@{ $self->{timeout} }) {
680	for my $server (@{ $self->{server} }) {	964	for my $server (@{ $self->{server} }) {
…		…
686	}	970	}
687		971
688	sub _feed {	972	sub _feed {
689	my ($self, $res) = @_;	973	my ($self, $res) = @_;
690		974
		975	($res) = $res =~ /^(.*)$/s
		976	if AnyEvent::TAINT && $self->{untaint};
		977
691	$res = dns_unpack $res	978	$res = dns_unpack $res
692	or return;	979	or return;
693		980
694	my $id = $self->{id}{$res->{id}};	981	my $id = $self->{id}{$res->{id}};
695		982
…		…
698	$NOW = time;	985	$NOW = time;
699	$id->[1]->($res);	986	$id->[1]->($res);
700	}	987	}
701		988
702	sub _recv {	989	sub _recv {
703	my ($self) = @_;	990	my ($self, $pkt, $peer) = @_;
704		991
705	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	992	# we ignore errors (often one gets port unreachable, but there is
		993	# no good way to take advantage of that.
		994
706	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	995	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
707		996
708	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	997	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
709		998
710	$self->_feed ($res);	999	$self->_feed ($pkt);
711	}
712	}	1000	}
713		1001
		1002	sub _free_id {
		1003	my ($self, $id, $timeout) = @_;
		1004
		1005	if ($timeout) {
		1006	# we need to block the id for a while
		1007	$self->{id}{$id} = 1;
		1008	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		1009	} else {
		1010	# we can quickly recycle the id
		1011	delete $self->{id}{$id};
		1012	}
		1013
		1014	--$self->{outstanding};
		1015	$self->_scheduler;
		1016	}
		1017
		1018	# execute a single request, involves sending it with timeouts to multiple servers
714	sub _exec {	1019	sub _exec {
715	my ($self, $req, $retry) = @_;	1020	my ($self, $req) = @_;
716		1021
		1022	my $retry; # of retries
		1023	my $do_retry;
		1024
		1025	$do_retry = sub {
717	if (my $retry_cfg = $self->{retry}[$retry]) {	1026	my $retry_cfg = $self->{retry}[$retry++]
		1027	or do {
		1028	# failure
		1029	$self->_free_id ($req->[2], $retry > 1);
		1030	undef $do_retry; return $req->[1]->();
		1031	};
		1032
718	my ($server, $timeout) = @$retry_cfg;	1033	my ($server, $timeout) = @$retry_cfg;
719		1034
720	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1035	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
721	$NOW = time;	1036	$NOW = time;
722		1037
723	# timeout, try next	1038	# timeout, try next
724	$self->_exec ($req, $retry + 1);	1039	&$do_retry if $do_retry;
725	}), sub {	1040	}), sub {
726	my ($res) = @_;	1041	my ($res) = @_;
727		1042
728	if ($res->{tc}) {	1043	if ($res->{tc}) {
729	# success, but truncated, so use tcp	1044	# success, but truncated, so use tcp
730	AnyEvent::Util::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1045	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1046	return unless $do_retry; # some other request could have invalidated us already
		1047
731	my ($fh) = @_	1048	my ($fh) = @_
732	or return $self->_exec ($req, $retry + 1);	1049	or return &$do_retry;
733		1050
		1051	require AnyEvent::Handle;
		1052
734	my $handle = new AnyEvent::Handle	1053	my $handle; $handle = new AnyEvent::Handle
735	fh => $fh,	1054	fh => $fh,
		1055	timeout => $timeout,
736	on_error => sub {	1056	on_error => sub {
		1057	undef $handle;
		1058	return unless $do_retry; # some other request could have invalidated us already
737	# failure, try next	1059	# failure, try next
738	$self->_exec ($req, $retry + 1);	1060	&$do_retry;
739	};	1061	};
740		1062
741	$handle->push_write (pack "n/a", $req->[0]);	1063	$handle->push_write (pack "n/a", $req->[0]);
742	$handle->push_read_chunk (2, sub {	1064	$handle->push_read (chunk => 2, sub {
743	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1065	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1066	undef $handle;
744	$self->_feed ($_[1]);	1067	$self->_feed ($_[1]);
745	});	1068	});
746	});	1069	});
747	shutdown $fh, 1;
748		1070
749	}, sub { $timeout };	1071	}, sub { $timeout });
750		1072
751	} else {	1073	} else {
752	# success	1074	# success
753	$self->{id}{$req->[2]} = 1;	1075	$self->_free_id ($req->[2], $retry > 1);
754	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1076	undef $do_retry; return $req->[1]->($res);
755	--$self->{outstanding};
756	$self->_scheduler;
757
758	$req->[1]->($res);
759	}	1077	}
760	}];	1078	}];
		1079
		1080	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
761		1081
762	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1082	my $fh = AF_INET == Socket::sockaddr_family ($sa)
763	} else {	1083	? $self->{fh4} : $self->{fh6}
764	# failure	1084	or return &$do_retry;
765	$self->{id}{$req->[2]} = 1;
766	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
767	--$self->{outstanding};
768	$self->_scheduler;
769		1085
770	$req->[1]->();	1086	send $fh, $req->[0], 0, $sa;
771	}	1087	};
		1088
		1089	&$do_retry;
772	}	1090	}
773		1091
774	sub _scheduler {	1092	sub _scheduler {
775	my ($self) = @_;	1093	my ($self) = @_;
776		1094
		1095	no strict 'refs';
		1096
777	$NOW = time;	1097	$NOW = time;
778		1098
779	# first clear id reuse queue	1099	# first clear id reuse queue
780	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1100	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
781	while @{ $self->{reuse_q} } && $self->{reuse_q}[0] <= $NOW;	1101	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;
782		1102
783	while ($self->{outstanding} < $self->{max_outstanding}) {	1103	while ($self->{outstanding} < $self->{max_outstanding}) {
784	my $req = shift @{ $self->{queue} }	1104
		1105	if (@{ $self->{reuse_q} } >= 30000) {
		1106	# we ran out of ID's, wait a bit
		1107	$self->{reuse_to} \|\|= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub {
		1108	delete $self->{reuse_to};
		1109	$self->_scheduler;
		1110	});
785	or last;	1111	last;
786
787	while () {
788	$req->[2] = int rand 65536;
789	last unless exists $self->{id}{$req->[2]};
790	}	1112	}
791		1113
		1114	if (my $req = shift @{ $self->{queue} }) {
		1115	# found a request in the queue, execute it
		1116	while () {
		1117	$req->[2] = int rand 65536;
		1118	last unless exists $self->{id}{$req->[2]};
		1119	}
		1120
		1121	++$self->{outstanding};
792	$self->{id}{$req->[2]} = 1;	1122	$self->{id}{$req->[2]} = 1;
793	substr $req->[0], 0, 2, pack "n", $req->[2];	1123	substr $req->[0], 0, 2, pack "n", $req->[2];
794		1124
795	++$self->{outstanding};
796	$self->_exec ($req, 0);	1125	$self->_exec ($req);
		1126
		1127	} elsif (my $cb = shift @{ $self->{wait} }) {
		1128	# found a wait_for_slot callback, call that one first
		1129	$cb->($self);
		1130
		1131	} else {
		1132	# nothing to do, just exit
		1133	last;
		1134	}
797	}	1135	}
798	}	1136	}
799		1137
800	=item $resolver->request ($req, $cb->($res))	1138	=item $resolver->request ($req, $cb->($res))
801		1139
		1140	This is the main low-level workhorse for sending DNS requests.
		1141
802	Sends a single request (a hash-ref formated as specified for	1142	This function sends a single request (a hash-ref formated as specified
803	C<dns_pack>) to the configured nameservers including	1143	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1144	response. It handles timeouts, retries and automatically falls back to
		1145	virtual circuit mode (TCP) when it receives a truncated reply.
		1146
804	retries. Calls the callback with the decoded response packet if a reply	1147	Calls the callback with the decoded response packet if a reply was
805	was received, or no arguments on timeout.	1148	received, or no arguments in case none of the servers answered.
806		1149
807	=cut	1150	=cut
808		1151
809	sub request($$) {	1152	sub request($$) {
810	my ($self, $req, $cb) = @_;	1153	my ($self, $req, $cb) = @_;
811		1154
812	push @{ $self->{queue} }, [dns_pack $req, $cb];	1155	push @{ $self->{queue} }, [dns_pack $req, $cb];
813	$self->_scheduler;	1156	$self->_scheduler;
814	}	1157	}
815		1158
816	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1159	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
817		1160
818	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1161	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
819	qtype of "*" is supported and means "any").	1162
		1163	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1164	a lowercase name (you have to look at the source to see which aliases are
		1165	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1166	more are known to this module). A C<$qtype> of "*" is supported and means
		1167	"any" record type.
820		1168
821	The callback will be invoked with a list of matching result records or	1169	The callback will be invoked with a list of matching result records or
822	none on any error or if the name could not be found.	1170	none on any error or if the name could not be found.
823		1171
824	CNAME chains (although illegal) are followed up to a length of 8.	1172	CNAME chains (although illegal) are followed up to a length of 10.
825		1173
		1174	The callback will be invoked with arraryefs of the form C<[$name, $type,
		1175	$class, @data>], where C<$name> is the domain name, C<$type> a type string
		1176	or number, C<$class> a class name and @data is resource-record-dependent
		1177	data. For C<a> records, this will be the textual IPv4 addresses, for C<ns>
		1178	or C<cname> records this will be a domain name, for C<txt> records these
		1179	are all the strings and so on.
		1180
		1181	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1182	decoded. All resource records not known to this module will have
		1183	the raw C<rdata> field as fourth entry.
		1184
826	Note that this resolver is just a stub resolver: it requires a nameserver	1185	Note that this resolver is just a stub resolver: it requires a name server
827	supporting recursive queries, will not do any recursive queries itself and	1186	supporting recursive queries, will not do any recursive queries itself and
828	is not secure when used against an untrusted name server.	1187	is not secure when used against an untrusted name server.
829		1188
830	The following options are supported:	1189	The following options are supported:
831		1190
…		…
833		1192
834	=item search => [$suffix...]	1193	=item search => [$suffix...]
835		1194
836	Use the given search list (which might be empty), by appending each one	1195	Use the given search list (which might be empty), by appending each one
837	in turn to the C<$qname>. If this option is missing then the configured	1196	in turn to the C<$qname>. If this option is missing then the configured
838	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1197	C<ndots> and C<search> values define its value (depending on C<ndots>, the
839	then the searchlist will be ignored.	1198	empty suffix will be prepended or appended to that C<search> value). If
		1199	the C<$qname> ends in a dot, then the searchlist will be ignored.
840		1200
841	=item accept => [$type...]	1201	=item accept => [$type...]
842		1202
843	Lists the acceptable result types: only result types in this set will be	1203	Lists the acceptable result types: only result types in this set will be
844	accepted and returned. The default includes the C<$qtype> and nothing	1204	accepted and returned. The default includes the C<$qtype> and nothing
845	else.	1205	else. If this list includes C<cname>, then CNAME-chains will not be
		1206	followed (because you asked for the CNAME record).
846		1207
847	=item class => "class"	1208	=item class => "class"
848		1209
849	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1210	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
850	hesiod are the only ones making sense). The default is "in", of course.	1211	hesiod are the only ones making sense). The default is "in", of course.
851		1212
852	=back	1213	=back
853		1214
854	Examples:	1215	Examples:
855		1216
856	$res->resolve ("ruth.plan9.de", "a", sub {	1217	# full example, you can paste this into perl:
857	warn Dumper [@_];	1218	use Data::Dumper;
858	});	1219	use AnyEvent::DNS;
		1220	AnyEvent::DNS::resolver->resolve (
		1221	"google.com", "*", my $cv = AnyEvent->condvar);
		1222	warn Dumper [$cv->recv];
859		1223
		1224	# shortened result:
860	[	1225	# [
		1226	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1227	# 2008052701, 7200, 1800, 1209600, 300 ],
861	[	1228	# [
862	'ruth.schmorp.de',	1229	# 'google.com', 'txt', 'in',
863	'a',	1230	# 'v=spf1 include:_netblocks.google.com ~all'
864	'in',	1231	# ],
865	'129.13.162.95'	1232	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1233	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1234	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
866	]	1235	# ]
		1236
		1237	# resolve a records:
		1238	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1239
		1240	# result:
		1241	# [
		1242	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
867	]	1243	# ]
868		1244
		1245	# resolve any records, but return only a and aaaa records:
869	$res->resolve ("test1.laendle", "*",	1246	$res->resolve ("test1.laendle", "*",
870	accept => ["a", "aaaa"],	1247	accept => ["a", "aaaa"],
871	sub {	1248	sub {
872	warn Dumper [@_];	1249	warn Dumper [@_];
873	}	1250	}
874	);	1251	);
875		1252
876	[	1253	# result:
877	[	1254	# [
878	'test1.laendle',	1255	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
879	'a',	1256	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
880	'in',
881	'10.0.0.255'
882	],
883	[
884	'test1.laendle',
885	'aaaa',
886	'in',
887	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
888	]	1257	# ]
889	]
890		1258
891	=cut	1259	=cut
892		1260
893	sub resolve($%) {	1261	sub resolve($%) {
894	my $cb = pop;	1262	my $cb = pop;
…		…
907	my %atype = $opt{accept}	1275	my %atype = $opt{accept}
908	? map +($_ => 1), @{ $opt{accept} }	1276	? map +($_ => 1), @{ $opt{accept} }
909	: ($qtype => 1);	1277	: ($qtype => 1);
910		1278
911	# advance in searchlist	1279	# advance in searchlist
912	my $do_search; $do_search = sub {	1280	my ($do_search, $do_req);
		1281
		1282	$do_search = sub {
913	@search	1283	@search
914	or return $cb->();	1284	or (undef $do_search), (undef $do_req), return $cb->();
915		1285
916	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1286	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
917	my $depth = 2;	1287	my $depth = 10;
918		1288
919	# advance in cname-chain	1289	# advance in cname-chain
920	my $do_req; $do_req = sub {	1290	$do_req = sub {
921	$self->request ({	1291	$self->request ({
922	rd => 1,	1292	rd => 1,
923	qd => [[$name, $qtype, $class]],	1293	qd => [[$name, $qtype, $class]],
924	}, sub {	1294	}, sub {
925	my ($res) = @_	1295	my ($res) = @_
…		…
929		1299
930	while () {	1300	while () {
931	# results found?	1301	# results found?
932	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1302	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
933		1303
934	return $cb->(@rr)	1304	(undef $do_search), (undef $do_req), return $cb->(@rr)
935	if @rr;	1305	if @rr;
936		1306
937	# see if there is a cname we can follow	1307	# see if there is a cname we can follow
938	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1308	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
939		1309
940	if (@rr) {	1310	if (@rr) {
941	$depth--	1311	$depth--
942	or return $do_search->(); # cname chain too long	1312	or return $do_search->(); # cname chain too long
943		1313
944	$cname = 1;	1314	$cname = 1;
945	$name = $rr[0][3];	1315	$name = lc $rr[0][3];
946		1316
947	} elsif ($cname) {	1317	} elsif ($cname) {
948	# follow the cname	1318	# follow the cname
949	return $do_req->();	1319	return $do_req->();
950		1320
…		…
960	};	1330	};
961		1331
962	$do_search->();	1332	$do_search->();
963	}	1333	}
964		1334
		1335	=item $resolver->wait_for_slot ($cb->($resolver))
		1336
		1337	Wait until a free request slot is available and call the callback with the
		1338	resolver object.
		1339
		1340	A request slot is used each time a request is actually sent to the
		1341	nameservers: There are never more than C<max_outstanding> of them.
		1342
		1343	Although you can submit more requests (they will simply be queued until
		1344	a request slot becomes available), sometimes, usually for rate-limiting
		1345	purposes, it is useful to instead wait for a slot before generating the
		1346	request (or simply to know when the request load is low enough so one can
		1347	submit requests again).
		1348
		1349	This is what this method does: The callback will be called when submitting
		1350	a DNS request will not result in that request being queued. The callback
		1351	may or may not generate any requests in response.
		1352
		1353	Note that the callback will only be invoked when the request queue is
		1354	empty, so this does not play well if somebody else keeps the request queue
		1355	full at all times.
		1356
		1357	=cut
		1358
		1359	sub wait_for_slot {
		1360	my ($self, $cb) = @_;
		1361
		1362	push @{ $self->{wait} }, $cb;
		1363	$self->_scheduler;
		1364	}
		1365
		1366	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
		1367
965	1;	1368	1;
966		1369
967	=back	1370	=back
968		1371
969	=head1 AUTHOR	1372	=head1 AUTHOR
970		1373
971	Marc Lehmann <schmorp@schmorp.de>	1374	Marc Lehmann <schmorp@schmorp.de>
972	http://home.schmorp.de/	1375	http://home.schmorp.de/
973		1376
974	=cut	1377	=cut
975		1378

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.10 by root, Fri May 23 06:03:51 2008 UTC vs. Revision 1.103 by root, Thu Jul 9 08:31:16 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.10 by root, Fri May 23 06:03:51 2008 UTC vs.
Revision 1.103 by root, Thu Jul 9 08:31:16 2009 UTC