[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 1.79 by root, Mon Nov 3 21:49:25 2008 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
		8
		9	my $cv = AnyEvent->condvar;
		10	AnyEvent::DNS::a "www.google.de", $cv;
		11	# ... later
		12	my @addrs = $cv->recv;
8		13
9	=head1 DESCRIPTION	14	=head1 DESCRIPTION
10		15
11	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
12	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
13		18
		19	The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional
		20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
		21	virtual circuit mode for large responses.
		22
14	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
15		24
16	=over 4	25	=over 4
17		26
18	=cut	27	=cut
…		…
20	package AnyEvent::DNS;	29	package AnyEvent::DNS;
21		30
22	no warnings;	31	no warnings;
23	use strict;	32	use strict;
24		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
25	use AnyEvent::Util ();	36	use AnyEvent ();
26	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
27		39
28	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.32;
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
224	opt => 41,	357	opt => 41,
225	spf => 99,	358	spf => 99,
226	tkey => 249,	359	tkey => 249,
227	tsig => 250,	360	tsig => 250,
228	ixfr => 251,	361	ixfr => 251,
…		…
241	"*" => 255,	374	"*" => 255,
242	);	375	);
243		376
244	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
245		378
246	# names MUST have a trailing dot
247	sub _enc_qname($) {	379	sub _enc_name($) {
248	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
249	}	381	}
250		382
251	sub _enc_qd() {	383	sub _enc_qd() {
252	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
253	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
254	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
255	}	387	}
256		388
257	sub _enc_rr() {	389	sub _enc_rr() {
258	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
259	}	391	}
260		392
261	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
262		394
263	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	395	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
264	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
265		397
266	Resource records are not yet encodable.	398	Resource records are not yet encodable.
267		399
268	Examples:	400	Examples:
269		401
270	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
271	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
272		404
273	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
274		406
275	{	407	{
276	id => 10000,	408	id => 10000,
277	op => "query",	409	op => "query",
278	rc => "nxdomain",	410	rc => "nxdomain",
279		411
280	# flags	412	# flags
281	qr => 1,	413	qr => 1,
282	aa => 0,	414	aa => 0,
283	tc => 0,	415	tc => 0,
284	rd => 0,	416	rd => 0,
285	ra => 0,	417	ra => 0,
286	ad => 0,	418	ad => 0,
287	cd => 0,	419	cd => 0,
288		420
289	qd => [@rr], # query section	421	qd => [@rr], # query section
290	an => [@rr], # answer section	422	an => [@rr], # answer section
291	ns => [@rr], # authority section	423	ns => [@rr], # authority section
292	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
293	}	425	}
294		426
295	=cut	427	=cut
296		428
297	sub dns_pack($) {	429	sub dns_pack($) {
298	my ($req) = @_;	430	my ($req) = @_;
…		…
311	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
312		444
313	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
314	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
315	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
316	EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
317		449
318	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
319	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
320	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
321	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
322		454
323	(EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size	455	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
324	}	456	}
325		457
326	our $ofs;	458	our $ofs;
327	our $pkt;	459	our $pkt;
328		460
329	# bitches	461	# bitches
330	sub _dec_qname {	462	sub _dec_name {
331	my @res;	463	my @res;
332	my $redir;	464	my $redir;
333	my $ptr = $ofs;	465	my $ptr = $ofs;
334	my $cnt;	466	my $cnt;
335		467
336	while () {	468	while () {
337	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
338		470
339	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
340		472
341	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
342	$ptr++;	474	$ptr++;
343	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
344	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
345	} elsif ($len) {	477	} elsif ($len) {
346	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
351	}	483	}
352	}	484	}
353	}	485	}
354		486
355	sub _dec_qd {	487	sub _dec_qd {
356	my $qname = _dec_qname;	488	my $qname = _dec_name;
357	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
358	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
359	}	491	}
360		492
361	our %dec_rr = (	493	our %dec_rr = (
362	1 => sub { Socket::inet_ntoa $_ }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
363	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
364	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
365	6 => sub {	497	6 => sub {
366	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
367	my $mname = _dec_qname;	499	my $mname = _dec_name;
368	my $rname = _dec_qname;	500	my $rname = _dec_name;
369	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
370	}, # soa	502	}, # soa
371	11 => sub { ((Socket::inet_aton substr $_, 0, 4), unpack "C a*", substr $_, 4) }, # wks	503	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
372	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
373	13 => sub { unpack "C/a C/a", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
374	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx	506	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
375	16 => sub { unpack "(C/a)*", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
376	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
377	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv	509	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		510	35 => sub { # naptr
		511	# requires perl 5.10, sorry
		512	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		513	local $ofs = $ofs + $offset - length;
		514	($order, $preference, $flags, $service, $regexp, _dec_name)
		515	},
378	99 => sub { unpack "(C/a)*", $_ }, # spf	516	99 => sub { unpack "(C/a)", $_ }, # spf
379	);	517	);
380		518
381	sub _dec_rr {	519	sub _dec_rr {
382	my $qname = _dec_qname;	520	my $name = _dec_name;
383		521
384	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;	522	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
385	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
386		524
387	[	525	[
388	$qname,	526	$name,
389	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
390	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
391	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
392	]	530	]
393	}	531	}
…		…
396		534
397	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
398		536
399	Examples:	537	Examples:
400		538
401	# a non-successful reply	539	# an unsuccessful reply
402	{	540	{
403	'qd' => [	541	'qd' => [
404	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
405	],	543	],
406	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
407	'ar' => [],	545	'ar' => [],
408	'ns' => [	546	'ns' => [
409	[	547	[
410	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
411	'soa',	549	'soa',
412	'in',	550	'in',
413	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
414	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
415	2008052201,	553	2008052201, 10800, 1800, 2592000, 86400
416	10800,
417	1800,
418	2592000,
419	86400
420	]	554	]
421	],	555	],
422	'tc' => '',	556	'tc' => '',
423	'ra' => 1,	557	'ra' => 1,
424	'qr' => 1,	558	'qr' => 1,
425	'id' => 45915,	559	'id' => 45915,
426	'aa' => '',	560	'aa' => '',
427	'an' => [],	561	'an' => [],
428	'rd' => 1,	562	'rd' => 1,
429	'op' => 'query'	563	'op' => 'query'
430	}	564	}
431		565
432	# a successful reply	566	# a successful reply
433		567
434	{	568	{
435	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
436	'rc' => 0,	570	'rc' => 0,
437	'ar' => [	571	'ar' => [
438	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
439	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
440	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
441	],	575	],
442	'ns' => [	576	'ns' => [
443	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
444	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
445	],	579	],
446	'tc' => '',	580	'tc' => '',
447	'ra' => 1,	581	'ra' => 1,
448	'qr' => 1,	582	'qr' => 1,
449	'id' => 64265,	583	'id' => 64265,
450	'aa' => '',	584	'aa' => '',
451	'an' => [	585	'an' => [
452	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
453	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
454	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
455	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
456	],	590	],
457	'rd' => 1,	591	'rd' => 1,
458	'op' => 0	592	'op' => 0
459	}	593	}
460		594
461	=cut	595	=cut
462		596
463	sub dns_unpack($) {	597	sub dns_unpack($) {
464	local $pkt = shift;	598	local $pkt = shift;
…		…
490		624
491	=back	625	=back
492		626
493	=head2 THE AnyEvent::DNS RESOLVER CLASS	627	=head2 THE AnyEvent::DNS RESOLVER CLASS
494		628
495	This is the class which deos the actual protocol work.	629	This is the class which does the actual protocol work.
496		630
497	=over 4	631	=over 4
498		632
499	=cut	633	=cut
500		634
…		…
520	our $RESOLVER;	654	our $RESOLVER;
521		655
522	sub resolver() {	656	sub resolver() {
523	$RESOLVER \|\| do {	657	$RESOLVER \|\| do {
524	$RESOLVER = new AnyEvent::DNS;	658	$RESOLVER = new AnyEvent::DNS;
525	$RESOLVER->load_resolv_conf;	659	$RESOLVER->os_config;
526	$RESOLVER	660	$RESOLVER
527	}	661	}
528	}	662	}
529		663
530	=item $resolver = new AnyEvent::DNS key => value...	664	=item $resolver = new AnyEvent::DNS key => value...
…		…
535		669
536	=over 4	670	=over 4
537		671
538	=item server => [...]	672	=item server => [...]
539		673
540	A list of server addressses (default C<v127.0.0.1>) in network format (4	674	A list of server addresses (default: C<v127.0.0.1>) in network format
541	octets for IPv4, 16 octets for IPv6 - not yet supported).	675	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		676	IPv6 are supported).
542		677
543	=item timeout => [...]	678	=item timeout => [...]
544		679
545	A list of timeouts to use (also determines the number of retries). To make	680	A list of timeouts to use (also determines the number of retries). To make
546	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	681	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
555	The number of dots (default: C<1>) that a name must have so that the resolver	690	The number of dots (default: C<1>) that a name must have so that the resolver
556	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
557		692
558	=item max_outstanding => $integer	693	=item max_outstanding => $integer
559		694
560	Most name servers do not handle many parallel requests very well. This option	695	Most name servers do not handle many parallel requests very well. This
561	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	696	option limits the number of outstanding requests to C<$integer>
562	if you request more than this many requests, then the additional requests will be queued	697	(default: C<10>), that means if you request more than this many requests,
563	until some other requests have been resolved.	698	then the additional requests will be queued until some other requests have
		699	been resolved.
		700
		701	=item reuse => $seconds
		702
		703	The number of seconds (default: C<300>) that a query id cannot be re-used
		704	after a timeout. If there was no time-out then query ids can be reused
		705	immediately.
564		706
565	=back	707	=back
566		708
567	=cut	709	=cut
568		710
569	sub new {	711	sub new {
570	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
571		713
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 {	714	my $self = bless {
578	server => [v127.0.0.1],	715	server => [],
579	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
580	search => [],	717	search => [],
581	ndots => 1,	718	ndots => 1,
582	max_outstanding => 10,	719	max_outstanding => 10,
583	reuse => 300, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
584	%arg,	721	%arg,
585	fh => $fh,
586	reuse_q => [],	722	reuse_q => [],
587	}, $class;	723	}, $class;
588		724
589	# search should default to gethostname's domain	725	# search should default to gethostname's domain
590	# but perl lacks a good posix module	726	# but perl lacks a good posix module
591		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
592	Scalar::Util::weaken (my $wself = $self);	732	Scalar::Util::weaken (my $wself = $self);
		733
		734	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		735	++$got_socket;
		736
		737	AnyEvent::Util::fh_nonblocking $fh4, 1;
		738	$self->{fh4} = $fh4;
593	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	739	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		740	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		741	$wself->_recv ($pkt, $peer);
		742	}
		743	});
		744	}
		745
		746	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		747	++$got_socket;
		748
		749	$self->{fh6} = $fh6;
		750	AnyEvent::Util::fh_nonblocking $fh6, 1;
		751	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		752	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		753	$wself->_recv ($pkt, $peer);
		754	}
		755	});
		756	}
		757
		758	$got_socket
		759	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
594		760
595	$self->_compile;	761	$self->_compile;
596		762
597	$self	763	$self
598	}	764	}
599		765
600	=item $resolver->parse_resolv_conv ($string)	766	=item $resolver->parse_resolv_conv ($string)
601		767
602	Parses the given string a sif it were a F<resolv.conf> file. The following	768	Parses the given string as if it were a F<resolv.conf> file. The following
603	directives are supported:	769	directives are supported (but not necessarily implemented).
604		770
605	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	771	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
606	C<options> (C<timeout>, C<attempts>, C<ndots>).	772	C<options> (C<timeout>, C<attempts>, C<ndots>).
607		773
608	Everything else is silently ignored.	774	Everything else is silently ignored.
…		…
620	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
621	if (/^\s*#/) {	787	if (/^\s*#/) {
622	# comment	788	# comment
623	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
624	my $ip = $1;	790	my $ip = $1;
625	if (AnyEvent::Util::dotted_quad $ip) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
626	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	792	push @{ $self->{server} }, $ipn;
627	} else {	793	} else {
628	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
629	}	795	}
630	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
631	$self->{search} = [$1];	797	$self->{search} = [$1];
…		…
652	if $attempts;	818	if $attempts;
653		819
654	$self->_compile;	820	$self->_compile;
655	}	821	}
656		822
657	=item $resolver->load_resolv_conf	823	=item $resolver->os_config
658		824
659	Tries to load and parse F</etc/resolv.conf>. If there will ever be windows	825	Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various
660	support, then this function will do the right thing under windows, too.	826	egregious hacks on windows to force the DNS servers and searchlist out of the system.
661		827
662	=cut	828	=cut
663		829
664	sub load_resolv_conf {	830	sub os_config {
665	my ($self) = @_;	831	my ($self) = @_;
666		832
		833	$self->{server} = [];
		834	$self->{search} = [];
		835
		836	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		837	no strict 'refs';
		838
		839	# there are many options to find the current nameservers etc. on windows
		840	# all of them don't work consistently:
		841	# - the registry thing needs separate code on win32 native vs. cygwin
		842	# - the registry layout differs between windows versions
		843	# - calling windows api functions doesn't work on cygwin
		844	# - ipconfig uses locale-specific messages
		845
		846	# we use ipconfig parsing because, despite all its brokenness,
		847	# it seems most stable in practise.
		848	# for good measure, we append a fallback nameserver to our list.
		849
		850	if (open my $fh, "ipconfig /all \|") {
		851	# parsing strategy: we go through the output and look for
		852	# :-lines with DNS in them. everything in those is regarded as
		853	# either a nameserver (if it parses as an ip address), or a suffix
		854	# (all else).
		855
		856	my $dns;
		857	while (<$fh>) {
		858	if (s/^\s.\bdns\b.://i) {
		859	$dns = 1;
		860	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		861	$dns = 0;
		862	}
		863	if ($dns && /^\s(\S+)\s$/) {
		864	my $s = $1;
		865	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		866	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		867	push @{ $self->{server} }, $ipn;
		868	} else {
		869	push @{ $self->{search} }, $s;
		870	}
		871	}
		872	}
		873
		874	# always add one fallback server
		875	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
		876
		877	$self->_compile;
		878	}
		879	} else {
		880	# try resolv.conf everywhere
		881
667	open my $fh, "</etc/resolv.conf"	882	if (open my $fh, "</etc/resolv.conf") {
668	or return;
669
670	local $/;	883	local $/;
671	$self->parse_resolv_conf (<$fh>);	884	$self->parse_resolv_conf (<$fh>);
		885	}
		886	}
		887	}
		888
		889	=item $resolver->timeout ($timeout, ...)
		890
		891	Sets the timeout values. See the C<timeout> constructor argument (and note
		892	that this method uses the values itself, not an array-reference).
		893
		894	=cut
		895
		896	sub timeout {
		897	my ($self, @timeout) = @_;
		898
		899	$self->{timeout} = \@timeout;
		900	$self->_compile;
		901	}
		902
		903	=item $resolver->max_outstanding ($nrequests)
		904
		905	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		906	C<max_outstanding> constructor argument.
		907
		908	=cut
		909
		910	sub max_outstanding {
		911	my ($self, $max) = @_;
		912
		913	$self->{max_outstanding} = $max;
		914	$self->_scheduler;
672	}	915	}
673		916
674	sub _compile {	917	sub _compile {
675	my $self = shift;	918	my $self = shift;
		919
		920	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		921	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		922
		923	unless (@{ $self->{server} }) {
		924	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		925	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		926	}
676		927
677	my @retry;	928	my @retry;
678		929
679	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
680	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
698	$NOW = time;	949	$NOW = time;
699	$id->[1]->($res);	950	$id->[1]->($res);
700	}	951	}
701		952
702	sub _recv {	953	sub _recv {
703	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
704		955
705	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	956	# we ignore errors (often one gets port unreachable, but there is
		957	# no good way to take advantage of that.
		958
706	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
707		960
708	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
709		962
710	$self->_feed ($res);	963	$self->_feed ($pkt);
711	}
712	}	964	}
713		965
		966	sub _free_id {
		967	my ($self, $id, $timeout) = @_;
		968
		969	if ($timeout) {
		970	# we need to block the id for a while
		971	$self->{id}{$id} = 1;
		972	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		973	} else {
		974	# we can quickly recycle the id
		975	delete $self->{id}{$id};
		976	}
		977
		978	--$self->{outstanding};
		979	$self->_scheduler;
		980	}
		981
		982	# execute a single request, involves sending it with timeouts to multiple servers
714	sub _exec {	983	sub _exec {
715	my ($self, $req, $retry) = @_;	984	my ($self, $req) = @_;
716		985
		986	my $retry; # of retries
		987	my $do_retry;
		988
		989	$do_retry = sub {
717	if (my $retry_cfg = $self->{retry}[$retry]) {	990	my $retry_cfg = $self->{retry}[$retry++]
		991	or do {
		992	# failure
		993	$self->_free_id ($req->[2], $retry > 1);
		994	undef $do_retry; return $req->[1]->();
		995	};
		996
718	my ($server, $timeout) = @$retry_cfg;	997	my ($server, $timeout) = @$retry_cfg;
719		998
720	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
721	$NOW = time;	1000	$NOW = time;
722		1001
723	# timeout, try next	1002	# timeout, try next
724	$self->_exec ($req, $retry + 1);	1003	&$do_retry if $do_retry;
725	}), sub {	1004	}), sub {
726	my ($res) = @_;	1005	my ($res) = @_;
727		1006
728	if ($res->{tc}) {	1007	if ($res->{tc}) {
729	# success, but truncated, so use tcp	1008	# success, but truncated, so use tcp
730	AnyEvent::Util::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1009	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1010	return unless $do_retry; # some other request could have invalidated us already
		1011
731	my ($fh) = @_	1012	my ($fh) = @_
732	or return $self->_exec ($req, $retry + 1);	1013	or return &$do_retry;
733		1014
734	my $handle = new AnyEvent::Handle	1015	my $handle; $handle = new AnyEvent::Handle
735	fh => $fh,	1016	fh => $fh,
		1017	timeout => $timeout,
736	on_error => sub {	1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
737	# failure, try next	1021	# failure, try next
738	$self->_exec ($req, $retry + 1);	1022	&$do_retry;
739	};	1023	};
740		1024
741	$handle->push_write (pack "n/a", $req->[0]);	1025	$handle->push_write (pack "n/a", $req->[0]);
742	$handle->push_read_chunk (2, sub {	1026	$handle->push_read (chunk => 2, sub {
743	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
744	$self->_feed ($_[1]);	1029	$self->_feed ($_[1]);
745	});	1030	});
746	});	1031	});
747	shutdown $fh, 1;
748		1032
749	}, sub { $timeout };	1033	}, sub { $timeout });
750		1034
751	} else {	1035	} else {
752	# success	1036	# success
753	$self->{id}{$req->[2]} = 1;	1037	$self->_free_id ($req->[2], $retry > 1);
754	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1038	undef $do_retry; return $req->[1]->($res);
755	--$self->{outstanding};
756	$self->_scheduler;
757
758	$req->[1]->($res);
759	}	1039	}
760	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
761		1043
762	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
763	} else {	1045	? $self->{fh4} : $self->{fh6}
764	# failure	1046	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		1047
770	$req->[1]->();	1048	send $fh, $req->[0], 0, $sa;
771	}	1049	};
		1050
		1051	&$do_retry;
772	}	1052	}
773		1053
774	sub _scheduler {	1054	sub _scheduler {
775	my ($self) = @_;	1055	my ($self) = @_;
776		1056
		1057	no strict 'refs';
		1058
777	$NOW = time;	1059	$NOW = time;
778		1060
779	# first clear id reuse queue	1061	# first clear id reuse queue
780	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
781	while @{ $self->{reuse_q} } && $self->{reuse_q}[0] <= $NOW;	1063	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;
782		1064
783	while ($self->{outstanding} < $self->{max_outstanding}) {	1065	while ($self->{outstanding} < $self->{max_outstanding}) {
784	my $req = shift @{ $self->{queue} }	1066
		1067	if (@{ $self->{reuse_q} } >= 30000) {
		1068	# we ran out of ID's, wait a bit
		1069	$self->{reuse_to} \|\|= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub {
		1070	delete $self->{reuse_to};
		1071	$self->_scheduler;
		1072	});
785	or last;	1073	last;
786
787	while () {
788	$req->[2] = int rand 65536;
789	last unless exists $self->{id}{$req->[2]};
790	}	1074	}
791		1075
		1076	if (my $req = shift @{ $self->{queue} }) {
		1077	# found a request in the queue, execute it
		1078	while () {
		1079	$req->[2] = int rand 65536;
		1080	last unless exists $self->{id}{$req->[2]};
		1081	}
		1082
		1083	++$self->{outstanding};
792	$self->{id}{$req->[2]} = 1;	1084	$self->{id}{$req->[2]} = 1;
793	substr $req->[0], 0, 2, pack "n", $req->[2];	1085	substr $req->[0], 0, 2, pack "n", $req->[2];
794		1086
795	++$self->{outstanding};
796	$self->_exec ($req, 0);	1087	$self->_exec ($req);
		1088
		1089	} elsif (my $cb = shift @{ $self->{wait} }) {
		1090	# found a wait_for_slot callback, call that one first
		1091	$cb->($self);
		1092
		1093	} else {
		1094	# nothing to do, just exit
		1095	last;
		1096	}
797	}	1097	}
798	}	1098	}
799		1099
800	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
801		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
802	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
803	C<dns_pack>) to the configured nameservers including	1105	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1106	response. It handles timeouts, retries and automatically falls back to
		1107	virtual circuit mode (TCP) when it receives a truncated reply.
		1108
804	retries. Calls the callback with the decoded response packet if a reply	1109	Calls the callback with the decoded response packet if a reply was
805	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
806		1111
807	=cut	1112	=cut
808		1113
809	sub request($$) {	1114	sub request($$) {
810	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
…		…
813	$self->_scheduler;	1118	$self->_scheduler;
814	}	1119	}
815		1120
816	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))
817		1122
818	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1123	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
819	qtype of "*" is supported and means "any").	1124
		1125	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1126	a lowercase name (you have to look at the source to see which aliases are
		1127	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1128	more are known to this module). A C<$qtype> of "*" is supported and means
		1129	"any" record type.
820		1130
821	The callback will be invoked with a list of matching result records or	1131	The callback will be invoked with a list of matching result records or
822	none on any error or if the name could not be found.	1132	none on any error or if the name could not be found.
823		1133
824	CNAME chains (although illegal) are followed up to a length of 8.	1134	CNAME chains (although illegal) are followed up to a length of 10.
825		1135
		1136	The callback will be invoked with an result code in string form (noerror,
		1137	formerr, servfail, nxdomain, notimp, refused and so on), or numerical
		1138	form if the result code is not supported. The remaining arguments are
		1139	arraryefs of the form C<[$name, $type, $class, @data>], where C<$name> is
		1140	the domain name, C<$type> a type string or number, C<$class> a class name
		1141	and @data is resource-record-dependent data. For C<a> records, this will
		1142	be the textual IPv4 addresses, for C<ns> or C<cname> records this will be
		1143	a domain name, for C<txt> records these are all the strings and so on.
		1144
		1145	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1146	decoded. All resource records not known to this module will have
		1147	the raw C<rdata> field as fourth entry.
		1148
826	Note that this resolver is just a stub resolver: it requires a nameserver	1149	Note that this resolver is just a stub resolver: it requires a name server
827	supporting recursive queries, will not do any recursive queries itself and	1150	supporting recursive queries, will not do any recursive queries itself and
828	is not secure when used against an untrusted name server.	1151	is not secure when used against an untrusted name server.
829		1152
830	The following options are supported:	1153	The following options are supported:
831		1154
…		…
833		1156
834	=item search => [$suffix...]	1157	=item search => [$suffix...]
835		1158
836	Use the given search list (which might be empty), by appending each one	1159	Use the given search list (which might be empty), by appending each one
837	in turn to the C<$qname>. If this option is missing then the configured	1160	in turn to the C<$qname>. If this option is missing then the configured
838	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1161	C<ndots> and C<search> values define its value (depending on C<ndots>, the
839	then the searchlist will be ignored.	1162	empty suffix will be prepended or appended to that C<search> value). If
		1163	the C<$qname> ends in a dot, then the searchlist will be ignored.
840		1164
841	=item accept => [$type...]	1165	=item accept => [$type...]
842		1166
843	Lists the acceptable result types: only result types in this set will be	1167	Lists the acceptable result types: only result types in this set will be
844	accepted and returned. The default includes the C<$qtype> and nothing	1168	accepted and returned. The default includes the C<$qtype> and nothing
845	else.	1169	else. If this list includes C<cname>, then CNAME-chains will not be
		1170	followed (because you asked for the CNAME record).
846		1171
847	=item class => "class"	1172	=item class => "class"
848		1173
849	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1174	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
850	hesiod are the only ones making sense). The default is "in", of course.	1175	hesiod are the only ones making sense). The default is "in", of course.
851		1176
852	=back	1177	=back
853		1178
854	Examples:	1179	Examples:
855		1180
856	$res->resolve ("ruth.plan9.de", "a", sub {	1181	# full example, you can paste this into perl:
857	warn Dumper [@_];	1182	use Data::Dumper;
858	});	1183	use AnyEvent::DNS;
		1184	AnyEvent::DNS::resolver->resolve (
		1185	"google.com", "*", my $cv = AnyEvent->condvar);
		1186	warn Dumper [$cv->recv];
859		1187
		1188	# shortened result:
860	[	1189	# [
		1190	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1191	# 2008052701, 7200, 1800, 1209600, 300 ],
861	[	1192	# [
862	'ruth.schmorp.de',	1193	# 'google.com', 'txt', 'in',
863	'a',	1194	# 'v=spf1 include:_netblocks.google.com ~all'
864	'in',	1195	# ],
865	'129.13.162.95'	1196	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1197	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1198	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
866	]	1199	# ]
		1200
		1201	# resolve a records:
		1202	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1203
		1204	# result:
		1205	# [
		1206	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
867	]	1207	# ]
868		1208
		1209	# resolve any records, but return only a and aaaa records:
869	$res->resolve ("test1.laendle", "*",	1210	$res->resolve ("test1.laendle", "*",
870	accept => ["a", "aaaa"],	1211	accept => ["a", "aaaa"],
871	sub {	1212	sub {
872	warn Dumper [@_];	1213	warn Dumper [@_];
873	}	1214	}
874	);	1215	);
875		1216
876	[	1217	# result:
877	[	1218	# [
878	'test1.laendle',	1219	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
879	'a',	1220	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
880	'in',
881	'10.0.0.255'
882	],
883	[
884	'test1.laendle',
885	'aaaa',
886	'in',
887	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
888	]	1221	# ]
889	]
890		1222
891	=cut	1223	=cut
892		1224
893	sub resolve($%) {	1225	sub resolve($%) {
894	my $cb = pop;	1226	my $cb = pop;
…		…
907	my %atype = $opt{accept}	1239	my %atype = $opt{accept}
908	? map +($_ => 1), @{ $opt{accept} }	1240	? map +($_ => 1), @{ $opt{accept} }
909	: ($qtype => 1);	1241	: ($qtype => 1);
910		1242
911	# advance in searchlist	1243	# advance in searchlist
912	my $do_search; $do_search = sub {	1244	my ($do_search, $do_req);
		1245
		1246	$do_search = sub {
913	@search	1247	@search
914	or return $cb->();	1248	or (undef $do_search), (undef $do_req), return $cb->();
915		1249
916	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1250	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
917	my $depth = 2;	1251	my $depth = 10;
918		1252
919	# advance in cname-chain	1253	# advance in cname-chain
920	my $do_req; $do_req = sub {	1254	$do_req = sub {
921	$self->request ({	1255	$self->request ({
922	rd => 1,	1256	rd => 1,
923	qd => [[$name, $qtype, $class]],	1257	qd => [[$name, $qtype, $class]],
924	}, sub {	1258	}, sub {
925	my ($res) = @_	1259	my ($res) = @_
…		…
929		1263
930	while () {	1264	while () {
931	# results found?	1265	# results found?
932	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1266	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
933		1267
934	return $cb->(@rr)	1268	(undef $do_search), (undef $do_req), return $cb->(@rr)
935	if @rr;	1269	if @rr;
936		1270
937	# see if there is a cname we can follow	1271	# see if there is a cname we can follow
938	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1272	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
939		1273
…		…
960	};	1294	};
961		1295
962	$do_search->();	1296	$do_search->();
963	}	1297	}
964		1298
		1299	=item $resolver->wait_for_slot ($cb->($resolver))
		1300
		1301	Wait until a free request slot is available and call the callback with the
		1302	resolver object.
		1303
		1304	A request slot is used each time a request is actually sent to the
		1305	nameservers: There are never more than C<max_outstanding> of them.
		1306
		1307	Although you can submit more requests (they will simply be queued until
		1308	a request slot becomes available), sometimes, usually for rate-limiting
		1309	purposes, it is useful to instead wait for a slot before generating the
		1310	request (or simply to know when the request load is low enough so one can
		1311	submit requests again).
		1312
		1313	This is what this method does: The callback will be called when submitting
		1314	a DNS request will not result in that request being queued. The callback
		1315	may or may not generate any requests in response.
		1316
		1317	Note that the callback will only be invoked when the request queue is
		1318	empty, so this does not play well if somebody else keeps the request queue
		1319	full at all times.
		1320
		1321	=cut
		1322
		1323	sub wait_for_slot {
		1324	my ($self, $cb) = @_;
		1325
		1326	push @{ $self->{wait} }, $cb;
		1327	$self->_scheduler;
		1328	}
		1329
		1330	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
		1331
965	1;	1332	1;
966		1333
967	=back	1334	=back
968		1335
969	=head1 AUTHOR	1336	=head1 AUTHOR
970		1337
971	Marc Lehmann <schmorp@schmorp.de>	1338	Marc Lehmann <schmorp@schmorp.de>
972	http://home.schmorp.de/	1339	http://home.schmorp.de/
973		1340
974	=cut	1341	=cut
975		1342

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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 1.79 by root, Mon Nov 3 21:49:25 2008 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 1.79 by root, Mon Nov 3 21:49:25 2008 UTC