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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.13 by root, Fri May 23 06:42:53 2008 UTC vs.
Revision 1.93 by root, Mon Jun 22 11:57:05 2009 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
		8
		9	my $cv = AnyEvent->condvar;
		10	AnyEvent::DNS::a "www.google.de", $cv;
		11	# ... later
		12	my @addrs = $cv->recv;
8		13
9	=head1 DESCRIPTION	14	=head1 DESCRIPTION
10		15
11	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
12	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
13		18
14	The stub resolver supports DNS over UDP, optional EDNS0 support for up to	19	The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional
15	4kiB datagrams and automatically falls back to virtual circuit mode for	20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
16	large responses.	21	virtual circuit mode for large responses.
17		22
18	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
19		24
20	=over 4	25	=over 4
21		26
…		…
24	package AnyEvent::DNS;	29	package AnyEvent::DNS;
25		30
26	no warnings;	31	no warnings;
27	use strict;	32	use strict;
28		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
29	use AnyEvent::Util ();	36	use AnyEvent ();
30	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
31		39
32	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.411;
33		41
34	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
35
36	Tries to resolve the given nodename and service name into sockaddr
37	structures usable to connect to this node and service in a
38	protocol-independent way. It works similarly to the getaddrinfo posix
39	function.
40
41	Example:
42
43	AnyEvent::DNS::addr "google.com", "http", AF_UNSPEC, SOCK_STREAM, sub { ... };
44		43
45	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
46		45
47	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).
48		51
49	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)	52	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)
50		53
51	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
52	first) list of domain names.	55	first) list of domain names.
…		…
62	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
63		66
64	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
65	of service records.	68	of service records.
66		69
67	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
68	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
69		72
70	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
71	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
72		75
73	Example:	76	Example:
74		77
75	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
76	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
77		80
78	=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)
79		93
80	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)
81	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
82		97
83	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.
84		108
85	Example:	109	Example:
86		110
87	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
88	# => f.root-servers.net	112	# => f.root-servers.net
89		113
90	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
91
92	Tries to resolve the given domain and passes all resource records found to
93	the callback.
94
95	=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
96		119
97	sub resolver;	120	sub resolver;
98		121
99	sub a($$) {	122	sub a($$) {
100	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
102	resolver->resolve ($domain => "a", sub {	125	resolver->resolve ($domain => "a", sub {
103	$cb->(map $_->[3], @_);	126	$cb->(map $_->[3], @_);
104	});	127	});
105	}	128	}
106		129
		130	sub aaaa($$) {
		131	my ($domain, $cb) = @_;
		132
		133	resolver->resolve ($domain => "aaaa", sub {
		134	$cb->(map $_->[3], @_);
		135	});
		136	}
		137
107	sub mx($$) {	138	sub mx($$) {
108	my ($domain, $cb) = @_;	139	my ($domain, $cb) = @_;
109		140
110	resolver->resolve ($domain => "mx", sub {	141	resolver->resolve ($domain => "mx", sub {
111	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);	142	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);
…		…
131	sub srv($$$$) {	162	sub srv($$$$) {
132	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
133		164
134	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
135	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
136	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
137	});	194	});
138	}	195	}
139		196
140	sub ptr($$) {	197	sub ptr($$) {
141	my ($ip, $cb) = @_;	198	my ($domain, $cb) = @_;
142		199
143	my $name;
144
145	if (AnyEvent::Util::dotted_quad $ip) {
146	$name = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
147	} else {
148	require Socket6;
149	$name = join ".",
150	(reverse split //,
151	unpack "H*", Socket6::inet_pton (Socket::AF_INET6, $ip)),
152	"ip6.arpa.";
153	}
154
155	resolver->resolve ($name => "ptr", sub {	200	resolver->resolve ($domain => "ptr", sub {
156	$cb->(map $_->[3], @_);	201	$cb->(map $_->[3], @_);
157	});	202	});
158	}	203	}
159		204
160	sub any($$) {	205	sub any($$) {
161	my ($domain, $cb) = @_;	206	my ($domain, $cb) = @_;
162		207
163	resolver->resolve ($domain => "*", $cb);	208	resolver->resolve ($domain => "*", $cb);
164	}	209	}
165		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
		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
166	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
167		288
168	=over 4	289	=over 4
169		290
170	=item $AnyEvent::DNS::EDNS0	291	=item $AnyEvent::DNS::EDNS0
171		292
172	This variable decides whether dns_pack automatically enables EDNS0	293	This variable decides whether dns_pack automatically enables EDNS0
173	support. By default, this is disabled (C<0>), but when set to C<1>,	294	support. By default, this is disabled (C<0>), unless overridden by
174	AnyEvent::DNS will use EDNS0 in all requests.	295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
		296	EDNS0 in all requests.
175		297
176	=cut	298	=cut
177		299
178	our $EDNS0 = 0; # set to 1 to enable (partial) edns0	300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0}*1; # set to 1 to enable (partial) edns0
179		301
180	our %opcode_id = (	302	our %opcode_id = (
181	query => 0,	303	query => 0,
182	iquery => 1,	304	iquery => 1,
183	status => 2,	305	status => 2,
…		…
229	minfo => 14,	351	minfo => 14,
230	mx => 15,	352	mx => 15,
231	txt => 16,	353	txt => 16,
232	aaaa => 28,	354	aaaa => 28,
233	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
		357	dname => 39, # rfc2672
234	opt => 41,	358	opt => 41,
235	spf => 99,	359	spf => 99,
236	tkey => 249,	360	tkey => 249,
237	tsig => 250,	361	tsig => 250,
238	ixfr => 251,	362	ixfr => 251,
…		…
251	"*" => 255,	375	"*" => 255,
252	);	376	);
253		377
254	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
255		379
256	# names MUST have a trailing dot
257	sub _enc_qname($) {	380	sub _enc_name($) {
258	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
259	}	382	}
260		383
261	sub _enc_qd() {	384	sub _enc_qd() {
262	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
263	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
264	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
265	}	388	}
266		389
267	sub _enc_rr() {	390	sub _enc_rr() {
268	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
269	}	392	}
270		393
271	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
272		395
273	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
274	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
275		398
276	Resource records are not yet encodable.	399	Resource records are not yet encodable.
277		400
278	Examples:	401	Examples:
279		402
280	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
281	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
282		405
283	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
284		407
285	{	408	{
286	id => 10000,	409	id => 10000,
287	op => "query",	410	op => "query",
288	rc => "nxdomain",	411	rc => "nxdomain",
289		412
290	# flags	413	# flags
291	qr => 1,	414	qr => 1,
292	aa => 0,	415	aa => 0,
293	tc => 0,	416	tc => 0,
294	rd => 0,	417	rd => 0,
295	ra => 0,	418	ra => 0,
296	ad => 0,	419	ad => 0,
297	cd => 0,	420	cd => 0,
298		421
299	qd => [@rr], # query section	422	qd => [@rr], # query section
300	an => [@rr], # answer section	423	an => [@rr], # answer section
301	ns => [@rr], # authority section	424	ns => [@rr], # authority section
302	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
303	}	426	}
304		427
305	=cut	428	=cut
306		429
307	sub dns_pack($) {	430	sub dns_pack($) {
308	my ($req) = @_;	431	my ($req) = @_;
…		…
321	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
322		445
323	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
324	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
325	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
326	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
327		450
328	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
329	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
330	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
331	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
332		455
333	($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
334	}	457	}
335		458
336	our $ofs;	459	our $ofs;
337	our $pkt;	460	our $pkt;
338		461
339	# bitches	462	# bitches
340	sub _dec_qname {	463	sub _dec_name {
341	my @res;	464	my @res;
342	my $redir;	465	my $redir;
343	my $ptr = $ofs;	466	my $ptr = $ofs;
344	my $cnt;	467	my $cnt;
345		468
346	while () {	469	while () {
347	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
348		471
349	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
350		473
351	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
352	$ptr++;	475	$ptr++;
353	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
354	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
355	} elsif ($len) {	478	} elsif ($len) {
356	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
361	}	484	}
362	}	485	}
363	}	486	}
364		487
365	sub _dec_qd {	488	sub _dec_qd {
366	my $qname = _dec_qname;	489	my $qname = _dec_name;
367	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
368	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
369	}	492	}
370		493
371	our %dec_rr = (	494	our %dec_rr = (
372	1 => sub { Socket::inet_ntoa $_ }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
373	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
374	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
375	6 => sub {	498	6 => sub {
376	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
377	my $mname = _dec_qname;	500	my $mname = _dec_name;
378	my $rname = _dec_qname;	501	my $rname = _dec_name;
379	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
380	}, # soa	503	}, # soa
381	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
382	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
383	13 => sub { unpack "C/a C/a", $_ }, # hinfo	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
384	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
385	16 => sub { unpack "(C/a)*", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
386	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	509	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
387	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
388	99 => sub { unpack "(C/a)*", $_ }, # spf	518	99 => sub { unpack "(C/a)", $_ }, # spf
389	);	519	);
390		520
391	sub _dec_rr {	521	sub _dec_rr {
392	my $qname = _dec_qname;	522	my $name = _dec_name;
393		523
394	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;
395	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
396		526
397	[	527	[
398	$qname,	528	$name,
399	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
400	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
401	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
402	]	532	]
403	}	533	}
…		…
406		536
407	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
408		538
409	Examples:	539	Examples:
410		540
411	# an unsuccessful reply	541	# an unsuccessful reply
412	{	542	{
413	'qd' => [	543	'qd' => [
414	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
415	],	545	],
416	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
417	'ar' => [],	547	'ar' => [],
418	'ns' => [	548	'ns' => [
419	[	549	[
420	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
421	'soa',	551	'soa',
422	'in',	552	'in',
423	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
424	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
425	2008052201, 10800, 1800, 2592000, 86400	555	2008052201, 10800, 1800, 2592000, 86400
426	]	556	]
427	],	557	],
428	'tc' => '',	558	'tc' => '',
429	'ra' => 1,	559	'ra' => 1,
430	'qr' => 1,	560	'qr' => 1,
431	'id' => 45915,	561	'id' => 45915,
432	'aa' => '',	562	'aa' => '',
433	'an' => [],	563	'an' => [],
434	'rd' => 1,	564	'rd' => 1,
435	'op' => 'query'	565	'op' => 'query'
436	}	566	}
437		567
438	# a successful reply	568	# a successful reply
439		569
440	{	570	{
441	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
442	'rc' => 0,	572	'rc' => 0,
443	'ar' => [	573	'ar' => [
444	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
445	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
446	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
447	],	577	],
448	'ns' => [	578	'ns' => [
449	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
450	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
451	],	581	],
452	'tc' => '',	582	'tc' => '',
453	'ra' => 1,	583	'ra' => 1,
454	'qr' => 1,	584	'qr' => 1,
455	'id' => 64265,	585	'id' => 64265,
456	'aa' => '',	586	'aa' => '',
457	'an' => [	587	'an' => [
458	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
459	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
460	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
461	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
462	],	592	],
463	'rd' => 1,	593	'rd' => 1,
464	'op' => 0	594	'op' => 0
465	}	595	}
466		596
467	=cut	597	=cut
468		598
469	sub dns_unpack($) {	599	sub dns_unpack($) {
470	local $pkt = shift;	600	local $pkt = shift;
…		…
525		655
526	our $RESOLVER;	656	our $RESOLVER;
527		657
528	sub resolver() {	658	sub resolver() {
529	$RESOLVER \|\| do {	659	$RESOLVER \|\| do {
530	$RESOLVER = new AnyEvent::DNS;	660	$RESOLVER = new AnyEvent::DNS untaint => 1;
531	$RESOLVER->load_resolv_conf;	661	$RESOLVER->os_config;
532	$RESOLVER	662	$RESOLVER
533	}	663	}
534	}	664	}
535		665
536	=item $resolver = new AnyEvent::DNS key => value...	666	=item $resolver = new AnyEvent::DNS key => value...
…		…
541		671
542	=over 4	672	=over 4
543		673
544	=item server => [...]	674	=item server => [...]
545		675
546	A list of server addressses (default: C<v127.0.0.1>) in network format (4	676	A list of server addresses (default: C<v127.0.0.1>) in network format
547	octets for IPv4, 16 octets for IPv6 - not yet supported).	677	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		678	IPv6 are supported).
548		679
549	=item timeout => [...]	680	=item timeout => [...]
550		681
551	A list of timeouts to use (also determines the number of retries). To make	682	A list of timeouts to use (also determines the number of retries). To make
552	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	683	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
561	The number of dots (default: C<1>) that a name must have so that the resolver	692	The number of dots (default: C<1>) that a name must have so that the resolver
562	tries to resolve the name without any suffixes first.	693	tries to resolve the name without any suffixes first.
563		694
564	=item max_outstanding => $integer	695	=item max_outstanding => $integer
565		696
566	Most name servers do not handle many parallel requests very well. This option	697	Most name servers do not handle many parallel requests very well. This
567	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	698	option limits the number of outstanding requests to C<$integer>
568	if you request more than this many requests, then the additional requests will be queued	699	(default: C<10>), that means if you request more than this many requests,
569	until some other requests have been resolved.	700	then the additional requests will be queued until some other requests have
		701	been resolved.
570		702
571	=item reuse => $seconds	703	=item reuse => $seconds
572		704
573	The number of seconds (default: C<60>) that a query id cannot be re-used	705	The number of seconds (default: C<300>) that a query id cannot be re-used
574	after a request. Since AnyEvent::DNS will only allocate up to 30000 ID's	706	after a timeout. If there was no time-out then query ids can be reused
575	at the same time, the long-term maximum number of requests per second is	707	immediately.
576	C<30000 / $seconds> (and thus C<500> requests/s by default).	708
		709	=item untaint => $boolean
		710
		711	When true, then the resolver will automatically untaint results, and might
		712	also ignore certain environment variables.
577		713
578	=back	714	=back
579		715
580	=cut	716	=cut
581		717
582	sub new {	718	sub new {
583	my ($class, %arg) = @_;	719	my ($class, %arg) = @_;
584		720
585	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
586	or Carp::croak "socket: $!";
587
588	AnyEvent::Util::fh_nonblocking $fh, 1;
589
590	my $self = bless {	721	my $self = bless {
591	server => [v127.0.0.1],	722	server => [],
592	timeout => [2, 5, 5],	723	timeout => [2, 5, 5],
593	search => [],	724	search => [],
594	ndots => 1,	725	ndots => 1,
595	max_outstanding => 10,	726	max_outstanding => 10,
596	reuse => 60, # reuse id's after 5 minutes only, if possible	727	reuse => 300,
597	%arg,	728	%arg,
598	fh => $fh,
599	reuse_q => [],	729	reuse_q => [],
600	}, $class;	730	}, $class;
601		731
602	# search should default to gethostname's domain	732	# search should default to gethostname's domain
603	# but perl lacks a good posix module	733	# but perl lacks a good posix module
604		734
		735	# try to create an ipv4 and an ipv6 socket
		736	# only fail when we cannot create either
		737	my $got_socket;
		738
605	Scalar::Util::weaken (my $wself = $self);	739	Scalar::Util::weaken (my $wself = $self);
		740
		741	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		742	++$got_socket;
		743
		744	AnyEvent::Util::fh_nonblocking $fh4, 1;
		745	$self->{fh4} = $fh4;
606	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	746	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		747	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		748	$wself->_recv ($pkt, $peer);
		749	}
		750	});
		751	}
		752
		753	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		754	++$got_socket;
		755
		756	$self->{fh6} = $fh6;
		757	AnyEvent::Util::fh_nonblocking $fh6, 1;
		758	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		759	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		760	$wself->_recv ($pkt, $peer);
		761	}
		762	});
		763	}
		764
		765	$got_socket
		766	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
607		767
608	$self->_compile;	768	$self->_compile;
609		769
610	$self	770	$self
611	}	771	}
612		772
613	=item $resolver->parse_resolv_conv ($string)	773	=item $resolver->parse_resolv_conv ($string)
614		774
615	Parses the given string a sif it were a F<resolv.conf> file. The following	775	Parses the given string as if it were a F<resolv.conf> file. The following
616	directives are supported:	776	directives are supported (but not necessarily implemented).
617		777
618	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	778	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
619	C<options> (C<timeout>, C<attempts>, C<ndots>).	779	C<options> (C<timeout>, C<attempts>, C<ndots>).
620		780
621	Everything else is silently ignored.	781	Everything else is silently ignored.
…		…
633	for (split /\n/, $resolvconf) {	793	for (split /\n/, $resolvconf) {
634	if (/^\s*#/) {	794	if (/^\s*#/) {
635	# comment	795	# comment
636	} elsif (/^\snameserver\s+(\S+)\s$/i) {	796	} elsif (/^\snameserver\s+(\S+)\s$/i) {
637	my $ip = $1;	797	my $ip = $1;
638	if (AnyEvent::Util::dotted_quad $ip) {	798	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
639	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	799	push @{ $self->{server} }, $ipn;
640	} else {	800	} else {
641	warn "nameserver $ip invalid and ignored\n";	801	warn "nameserver $ip invalid and ignored\n";
642	}	802	}
643	} elsif (/^\sdomain\s+(\S)\s+$/i) {	803	} elsif (/^\sdomain\s+(\S)\s+$/i) {
644	$self->{search} = [$1];	804	$self->{search} = [$1];
…		…
665	if $attempts;	825	if $attempts;
666		826
667	$self->_compile;	827	$self->_compile;
668	}	828	}
669		829
670	=item $resolver->load_resolv_conf	830	=item $resolver->os_config
671		831
672	Tries to load and parse F</etc/resolv.conf>. If there will ever be windows	832	Tries so load and parse F</etc/resolv.conf> on portable operating
673	support, then this function will do the right thing under windows, too.	833	systems. Tries various egregious hacks on windows to force the DNS servers
		834	and searchlist out of the system.
674		835
675	=cut	836	=cut
676		837
677	sub load_resolv_conf {	838	sub os_config {
678	my ($self) = @_;	839	my ($self) = @_;
679		840
		841	$self->{server} = [];
		842	$self->{search} = [];
		843
		844	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		845	no strict 'refs';
		846
		847	# there are many options to find the current nameservers etc. on windows
		848	# all of them don't work consistently:
		849	# - the registry thing needs separate code on win32 native vs. cygwin
		850	# - the registry layout differs between windows versions
		851	# - calling windows api functions doesn't work on cygwin
		852	# - ipconfig uses locale-specific messages
		853
		854	# we use ipconfig parsing because, despite all its brokenness,
		855	# it seems most stable in practise.
		856	# for good measure, we append a fallback nameserver to our list.
		857
		858	if (open my $fh, "ipconfig /all \|") {
		859	# parsing strategy: we go through the output and look for
		860	# :-lines with DNS in them. everything in those is regarded as
		861	# either a nameserver (if it parses as an ip address), or a suffix
		862	# (all else).
		863
		864	my $dns;
		865	while (<$fh>) {
		866	if (s/^\s.\bdns\b.://i) {
		867	$dns = 1;
		868	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		869	$dns = 0;
		870	}
		871	if ($dns && /^\s(\S+)\s$/) {
		872	my $s = $1;
		873	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		874	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		875	push @{ $self->{server} }, $ipn;
		876	} else {
		877	push @{ $self->{search} }, $s;
		878	}
		879	}
		880	}
		881
		882	# always add one fallback server
		883	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
		884
		885	$self->_compile;
		886	}
		887	} else {
		888	# try resolv.conf everywhere
		889
680	open my $fh, "</etc/resolv.conf"	890	if (open my $fh, "</etc/resolv.conf") {
681	or return;
682
683	local $/;	891	local $/;
684	$self->parse_resolv_conf (<$fh>);	892	$self->parse_resolv_conf (<$fh>);
		893	}
		894	}
		895	}
		896
		897	=item $resolver->timeout ($timeout, ...)
		898
		899	Sets the timeout values. See the C<timeout> constructor argument (and note
		900	that this method uses the values itself, not an array-reference).
		901
		902	=cut
		903
		904	sub timeout {
		905	my ($self, @timeout) = @_;
		906
		907	$self->{timeout} = \@timeout;
		908	$self->_compile;
		909	}
		910
		911	=item $resolver->max_outstanding ($nrequests)
		912
		913	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		914	C<max_outstanding> constructor argument.
		915
		916	=cut
		917
		918	sub max_outstanding {
		919	my ($self, $max) = @_;
		920
		921	$self->{max_outstanding} = $max;
		922	$self->_scheduler;
685	}	923	}
686		924
687	sub _compile {	925	sub _compile {
688	my $self = shift;	926	my $self = shift;
		927
		928	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		929	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		930
		931	unless (@{ $self->{server} }) {
		932	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		933	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		934	}
689		935
690	my @retry;	936	my @retry;
691		937
692	for my $timeout (@{ $self->{timeout} }) {	938	for my $timeout (@{ $self->{timeout} }) {
693	for my $server (@{ $self->{server} }) {	939	for my $server (@{ $self->{server} }) {
…		…
699	}	945	}
700		946
701	sub _feed {	947	sub _feed {
702	my ($self, $res) = @_;	948	my ($self, $res) = @_;
703		949
		950	($res) = $res =~ /^(.*)$/s
		951	if AnyEvent::TAINT && $self->{untaint};
		952
704	$res = dns_unpack $res	953	$res = dns_unpack $res
705	or return;	954	or return;
706		955
707	my $id = $self->{id}{$res->{id}};	956	my $id = $self->{id}{$res->{id}};
708		957
…		…
711	$NOW = time;	960	$NOW = time;
712	$id->[1]->($res);	961	$id->[1]->($res);
713	}	962	}
714		963
715	sub _recv {	964	sub _recv {
716	my ($self) = @_;	965	my ($self, $pkt, $peer) = @_;
717		966
718	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	967	# we ignore errors (often one gets port unreachable, but there is
		968	# no good way to take advantage of that.
		969
719	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	970	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
720		971
721	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	972	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
722		973
723	$self->_feed ($res);	974	$self->_feed ($pkt);
724	}
725	}	975	}
726		976
		977	sub _free_id {
		978	my ($self, $id, $timeout) = @_;
		979
		980	if ($timeout) {
		981	# we need to block the id for a while
		982	$self->{id}{$id} = 1;
		983	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		984	} else {
		985	# we can quickly recycle the id
		986	delete $self->{id}{$id};
		987	}
		988
		989	--$self->{outstanding};
		990	$self->_scheduler;
		991	}
		992
		993	# execute a single request, involves sending it with timeouts to multiple servers
727	sub _exec {	994	sub _exec {
728	my ($self, $req, $retry) = @_;	995	my ($self, $req) = @_;
729		996
		997	my $retry; # of retries
		998	my $do_retry;
		999
		1000	$do_retry = sub {
730	if (my $retry_cfg = $self->{retry}[$retry]) {	1001	my $retry_cfg = $self->{retry}[$retry++]
		1002	or do {
		1003	# failure
		1004	$self->_free_id ($req->[2], $retry > 1);
		1005	undef $do_retry; return $req->[1]->();
		1006	};
		1007
731	my ($server, $timeout) = @$retry_cfg;	1008	my ($server, $timeout) = @$retry_cfg;
732		1009
733	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1010	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
734	$NOW = time;	1011	$NOW = time;
735		1012
736	# timeout, try next	1013	# timeout, try next
737	$self->_exec ($req, $retry + 1);	1014	&$do_retry if $do_retry;
738	}), sub {	1015	}), sub {
739	my ($res) = @_;	1016	my ($res) = @_;
740		1017
741	if ($res->{tc}) {	1018	if ($res->{tc}) {
742	# success, but truncated, so use tcp	1019	# success, but truncated, so use tcp
743	AnyEvent::Util::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1020	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1021	return unless $do_retry; # some other request could have invalidated us already
		1022
744	my ($fh) = @_	1023	my ($fh) = @_
745	or return $self->_exec ($req, $retry + 1);	1024	or return &$do_retry;
746		1025
747	my $handle = new AnyEvent::Handle	1026	my $handle; $handle = new AnyEvent::Handle
748	fh => $fh,	1027	fh => $fh,
		1028	timeout => $timeout,
749	on_error => sub {	1029	on_error => sub {
		1030	undef $handle;
		1031	return unless $do_retry; # some other request could have invalidated us already
750	# failure, try next	1032	# failure, try next
751	$self->_exec ($req, $retry + 1);	1033	&$do_retry;
752	};	1034	};
753		1035
754	$handle->push_write (pack "n/a", $req->[0]);	1036	$handle->push_write (pack "n/a", $req->[0]);
755	$handle->push_read_chunk (2, sub {	1037	$handle->push_read (chunk => 2, sub {
756	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1038	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1039	undef $handle;
757	$self->_feed ($_[1]);	1040	$self->_feed ($_[1]);
758	});	1041	});
759	});	1042	});
760	shutdown $fh, 1;
761		1043
762	}, sub { $timeout };	1044	}, sub { $timeout });
763		1045
764	} else {	1046	} else {
765	# success	1047	# success
766	$self->{id}{$req->[2]} = 1;	1048	$self->_free_id ($req->[2], $retry > 1);
767	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1049	undef $do_retry; return $req->[1]->($res);
768	--$self->{outstanding};
769	$self->_scheduler;
770
771	$req->[1]->($res);
772	}	1050	}
773	}];	1051	}];
		1052
		1053	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
774		1054
775	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1055	my $fh = AF_INET == Socket::sockaddr_family ($sa)
776	} else {	1056	? $self->{fh4} : $self->{fh6}
777	# failure	1057	or return &$do_retry;
778	$self->{id}{$req->[2]} = 1;
779	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
780	--$self->{outstanding};
781	$self->_scheduler;
782		1058
783	$req->[1]->();	1059	send $fh, $req->[0], 0, $sa;
784	}	1060	};
		1061
		1062	&$do_retry;
785	}	1063	}
786		1064
787	sub _scheduler {	1065	sub _scheduler {
788	my ($self) = @_;	1066	my ($self) = @_;
		1067
		1068	no strict 'refs';
789		1069
790	$NOW = time;	1070	$NOW = time;
791		1071
792	# first clear id reuse queue	1072	# first clear id reuse queue
793	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1073	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
802	$self->_scheduler;	1082	$self->_scheduler;
803	});	1083	});
804	last;	1084	last;
805	}	1085	}
806		1086
807	my $req = shift @{ $self->{queue} }	1087	if (my $req = shift @{ $self->{queue} }) {
808	or last;	1088	# found a request in the queue, execute it
809
810	while () {	1089	while () {
811	$req->[2] = int rand 65536;	1090	$req->[2] = int rand 65536;
812	last unless exists $self->{id}{$req->[2]};	1091	last unless exists $self->{id}{$req->[2]};
		1092	}
		1093
		1094	++$self->{outstanding};
		1095	$self->{id}{$req->[2]} = 1;
		1096	substr $req->[0], 0, 2, pack "n", $req->[2];
		1097
		1098	$self->_exec ($req);
		1099
		1100	} elsif (my $cb = shift @{ $self->{wait} }) {
		1101	# found a wait_for_slot callback, call that one first
		1102	$cb->($self);
		1103
		1104	} else {
		1105	# nothing to do, just exit
		1106	last;
813	}	1107	}
814
815	$self->{id}{$req->[2]} = 1;
816	substr $req->[0], 0, 2, pack "n", $req->[2];
817
818	++$self->{outstanding};
819	$self->_exec ($req, 0);
820	}	1108	}
821	}	1109	}
822		1110
823	=item $resolver->request ($req, $cb->($res))	1111	=item $resolver->request ($req, $cb->($res))
824		1112
		1113	This is the main low-level workhorse for sending DNS requests.
		1114
825	Sends a single request (a hash-ref formated as specified for	1115	This function sends a single request (a hash-ref formated as specified
826	C<dns_pack>) to the configured nameservers including	1116	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1117	response. It handles timeouts, retries and automatically falls back to
		1118	virtual circuit mode (TCP) when it receives a truncated reply.
		1119
827	retries. Calls the callback with the decoded response packet if a reply	1120	Calls the callback with the decoded response packet if a reply was
828	was received, or no arguments on timeout.	1121	received, or no arguments in case none of the servers answered.
829		1122
830	=cut	1123	=cut
831		1124
832	sub request($$) {	1125	sub request($$) {
833	my ($self, $req, $cb) = @_;	1126	my ($self, $req, $cb) = @_;
834		1127
835	push @{ $self->{queue} }, [dns_pack $req, $cb];	1128	push @{ $self->{queue} }, [dns_pack $req, $cb];
836	$self->_scheduler;	1129	$self->_scheduler;
837	}	1130	}
838		1131
839	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1132	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
840		1133
841	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1134	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
842	qtype of "*" is supported and means "any").	1135
		1136	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1137	a lowercase name (you have to look at the source to see which aliases are
		1138	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1139	more are known to this module). A C<$qtype> of "*" is supported and means
		1140	"any" record type.
843		1141
844	The callback will be invoked with a list of matching result records or	1142	The callback will be invoked with a list of matching result records or
845	none on any error or if the name could not be found.	1143	none on any error or if the name could not be found.
846		1144
847	CNAME chains (although illegal) are followed up to a length of 8.	1145	CNAME chains (although illegal) are followed up to a length of 10.
848		1146
		1147	The callback will be invoked with arraryefs of the form C<[$name, $type,
		1148	$class, @data>], where C<$name> is the domain name, C<$type> a type string
		1149	or number, C<$class> a class name and @data is resource-record-dependent
		1150	data. For C<a> records, this will be the textual IPv4 addresses, for C<ns>
		1151	or C<cname> records this will be a domain name, for C<txt> records these
		1152	are all the strings and so on.
		1153
		1154	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1155	decoded. All resource records not known to this module will have
		1156	the raw C<rdata> field as fourth entry.
		1157
849	Note that this resolver is just a stub resolver: it requires a nameserver	1158	Note that this resolver is just a stub resolver: it requires a name server
850	supporting recursive queries, will not do any recursive queries itself and	1159	supporting recursive queries, will not do any recursive queries itself and
851	is not secure when used against an untrusted name server.	1160	is not secure when used against an untrusted name server.
852		1161
853	The following options are supported:	1162	The following options are supported:
854		1163
…		…
856		1165
857	=item search => [$suffix...]	1166	=item search => [$suffix...]
858		1167
859	Use the given search list (which might be empty), by appending each one	1168	Use the given search list (which might be empty), by appending each one
860	in turn to the C<$qname>. If this option is missing then the configured	1169	in turn to the C<$qname>. If this option is missing then the configured
861	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1170	C<ndots> and C<search> values define its value (depending on C<ndots>, the
862	then the searchlist will be ignored.	1171	empty suffix will be prepended or appended to that C<search> value). If
		1172	the C<$qname> ends in a dot, then the searchlist will be ignored.
863		1173
864	=item accept => [$type...]	1174	=item accept => [$type...]
865		1175
866	Lists the acceptable result types: only result types in this set will be	1176	Lists the acceptable result types: only result types in this set will be
867	accepted and returned. The default includes the C<$qtype> and nothing	1177	accepted and returned. The default includes the C<$qtype> and nothing
868	else.	1178	else. If this list includes C<cname>, then CNAME-chains will not be
		1179	followed (because you asked for the CNAME record).
869		1180
870	=item class => "class"	1181	=item class => "class"
871		1182
872	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1183	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
873	hesiod are the only ones making sense). The default is "in", of course.	1184	hesiod are the only ones making sense). The default is "in", of course.
874		1185
875	=back	1186	=back
876		1187
877	Examples:	1188	Examples:
878		1189
879	$res->resolve ("ruth.plan9.de", "a", sub {	1190	# full example, you can paste this into perl:
880	warn Dumper [@_];	1191	use Data::Dumper;
881	});	1192	use AnyEvent::DNS;
		1193	AnyEvent::DNS::resolver->resolve (
		1194	"google.com", "*", my $cv = AnyEvent->condvar);
		1195	warn Dumper [$cv->recv];
882		1196
		1197	# shortened result:
883	[	1198	# [
		1199	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1200	# 2008052701, 7200, 1800, 1209600, 300 ],
884	[	1201	# [
885	'ruth.schmorp.de',	1202	# 'google.com', 'txt', 'in',
886	'a',	1203	# 'v=spf1 include:_netblocks.google.com ~all'
887	'in',	1204	# ],
888	'129.13.162.95'	1205	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1206	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1207	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
889	]	1208	# ]
		1209
		1210	# resolve a records:
		1211	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1212
		1213	# result:
		1214	# [
		1215	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
890	]	1216	# ]
891		1217
		1218	# resolve any records, but return only a and aaaa records:
892	$res->resolve ("test1.laendle", "*",	1219	$res->resolve ("test1.laendle", "*",
893	accept => ["a", "aaaa"],	1220	accept => ["a", "aaaa"],
894	sub {	1221	sub {
895	warn Dumper [@_];	1222	warn Dumper [@_];
896	}	1223	}
897	);	1224	);
898		1225
899	[	1226	# result:
900	[	1227	# [
901	'test1.laendle',	1228	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
902	'a',	1229	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
903	'in',
904	'10.0.0.255'
905	],
906	[
907	'test1.laendle',
908	'aaaa',
909	'in',
910	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
911	]	1230	# ]
912	]
913		1231
914	=cut	1232	=cut
915		1233
916	sub resolve($%) {	1234	sub resolve($%) {
917	my $cb = pop;	1235	my $cb = pop;
…		…
930	my %atype = $opt{accept}	1248	my %atype = $opt{accept}
931	? map +($_ => 1), @{ $opt{accept} }	1249	? map +($_ => 1), @{ $opt{accept} }
932	: ($qtype => 1);	1250	: ($qtype => 1);
933		1251
934	# advance in searchlist	1252	# advance in searchlist
935	my $do_search; $do_search = sub {	1253	my ($do_search, $do_req);
		1254
		1255	$do_search = sub {
936	@search	1256	@search
937	or return $cb->();	1257	or (undef $do_search), (undef $do_req), return $cb->();
938		1258
939	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1259	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
940	my $depth = 2;	1260	my $depth = 10;
941		1261
942	# advance in cname-chain	1262	# advance in cname-chain
943	my $do_req; $do_req = sub {	1263	$do_req = sub {
944	$self->request ({	1264	$self->request ({
945	rd => 1,	1265	rd => 1,
946	qd => [[$name, $qtype, $class]],	1266	qd => [[$name, $qtype, $class]],
947	}, sub {	1267	}, sub {
948	my ($res) = @_	1268	my ($res) = @_
…		…
952		1272
953	while () {	1273	while () {
954	# results found?	1274	# results found?
955	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1275	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
956		1276
957	return $cb->(@rr)	1277	(undef $do_search), (undef $do_req), return $cb->(@rr)
958	if @rr;	1278	if @rr;
959		1279
960	# see if there is a cname we can follow	1280	# see if there is a cname we can follow
961	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1281	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
962		1282
…		…
983	};	1303	};
984		1304
985	$do_search->();	1305	$do_search->();
986	}	1306	}
987		1307
		1308	=item $resolver->wait_for_slot ($cb->($resolver))
		1309
		1310	Wait until a free request slot is available and call the callback with the
		1311	resolver object.
		1312
		1313	A request slot is used each time a request is actually sent to the
		1314	nameservers: There are never more than C<max_outstanding> of them.
		1315
		1316	Although you can submit more requests (they will simply be queued until
		1317	a request slot becomes available), sometimes, usually for rate-limiting
		1318	purposes, it is useful to instead wait for a slot before generating the
		1319	request (or simply to know when the request load is low enough so one can
		1320	submit requests again).
		1321
		1322	This is what this method does: The callback will be called when submitting
		1323	a DNS request will not result in that request being queued. The callback
		1324	may or may not generate any requests in response.
		1325
		1326	Note that the callback will only be invoked when the request queue is
		1327	empty, so this does not play well if somebody else keeps the request queue
		1328	full at all times.
		1329
		1330	=cut
		1331
		1332	sub wait_for_slot {
		1333	my ($self, $cb) = @_;
		1334
		1335	push @{ $self->{wait} }, $cb;
		1336	$self->_scheduler;
		1337	}
		1338
		1339	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
		1340
988	1;	1341	1;
989		1342
990	=back	1343	=back
991		1344
992	=head1 AUTHOR	1345	=head1 AUTHOR
993		1346
994	Marc Lehmann <schmorp@schmorp.de>	1347	Marc Lehmann <schmorp@schmorp.de>
995	http://home.schmorp.de/	1348	http://home.schmorp.de/
996		1349
997	=cut	1350	=cut
998		1351

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.13 by root, Fri May 23 06:42:53 2008 UTC vs. Revision 1.93 by root, Mon Jun 22 11:57:05 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.13 by root, Fri May 23 06:42:53 2008 UTC vs.
Revision 1.93 by root, Mon Jun 22 11:57:05 2009 UTC