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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.3 by root, Fri May 23 03:20:53 2008 UTC vs.
Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
		8
		9	my $cv = AnyEvent->condvar;
		10	AnyEvent::DNS::a "www.google.de", $cv;
		11	# ... later
		12	my @addrs = $cv->recv;
8		13
9	=head1 DESCRIPTION	14	=head1 DESCRIPTION
10		15
11	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
12	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
13		18
		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
16	# none yet
17		24
18	=over 4	25	=over 4
19		26
20	=cut	27	=cut
21		28
22	package AnyEvent::DNS;	29	package AnyEvent::DNS;
23		30
24	no warnings;	31	no warnings;
25	use strict;	32	use strict;
26		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
27	use AnyEvent::Util ();	36	use AnyEvent ();
		37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
		39
		40	our $VERSION = 4.45;
		41
		42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
		43
		44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
		45
		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).
		51
		52	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)
		53
		54	Tries to resolve the given domain into a sorted (lower preference value
		55	first) list of domain names.
		56
		57	=item AnyEvent::DNS::ns $domain, $cb->(@hostnames)
		58
		59	Tries to resolve the given domain name into a list of name servers.
		60
		61	=item AnyEvent::DNS::txt $domain, $cb->(@hostnames)
		62
		63	Tries to resolve the given domain name into a list of text records.
		64
		65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
		66
		67	Tries to resolve the given service, protocol and domain name into a list
		68	of service records.
		69
		70	Each C<$srv_rr> is an array reference with the following contents:
		71	C<[$priority, $weight, $transport, $target]>.
		72
		73	They will be sorted with lowest priority first, then randomly
		74	distributed by weight as per RFC 2782.
		75
		76	Example:
		77
		78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
		79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
		80
		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)
		93
		94	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)
		95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
		97
		98	=item AnyEvent::DNS::reverse_verify $ipv4_or_6, $cb->(@hostnames)
		99
		100	The same as C<reverse_lookup>, but does forward-lookups to verify that
		101	the resolved hostnames indeed point to the address, which makes spoofing
		102	harder.
		103
		104	If you want to resolve an address into a hostname, this is the preferred
		105	method: The DNS records could still change, but at least this function
		106	verified that the hostname, at one point in the past, pointed at the IP
		107	address you originally resolved.
		108
		109	Example:
		110
		111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
		112	# => f.root-servers.net
		113
		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
		119
		120	sub resolver;
		121
		122	sub a($$) {
		123	my ($domain, $cb) = @_;
		124
		125	resolver->resolve ($domain => "a", sub {
		126	$cb->(map $_->[3], @_);
		127	});
		128	}
		129
		130	sub aaaa($$) {
		131	my ($domain, $cb) = @_;
		132
		133	resolver->resolve ($domain => "aaaa", sub {
		134	$cb->(map $_->[3], @_);
		135	});
		136	}
		137
		138	sub mx($$) {
		139	my ($domain, $cb) = @_;
		140
		141	resolver->resolve ($domain => "mx", sub {
		142	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);
		143	});
		144	}
		145
		146	sub ns($$) {
		147	my ($domain, $cb) = @_;
		148
		149	resolver->resolve ($domain => "ns", sub {
		150	$cb->(map $_->[3], @_);
		151	});
		152	}
		153
		154	sub txt($$) {
		155	my ($domain, $cb) = @_;
		156
		157	resolver->resolve ($domain => "txt", sub {
		158	$cb->(map $_->[3], @_);
		159	});
		160	}
		161
		162	sub srv($$$$) {
		163	my ($service, $proto, $domain, $cb) = @_;
		164
		165	# todo, ask for any and check glue records
		166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
		167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
		194	});
		195	}
		196
		197	sub ptr($$) {
		198	my ($domain, $cb) = @_;
		199
		200	resolver->resolve ($domain => "ptr", sub {
		201	$cb->(map $_->[3], @_);
		202	});
		203	}
		204
		205	sub any($$) {
		206	my ($domain, $cb) = @_;
		207
		208	resolver->resolve ($domain => "*", $cb);
		209	}
		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
		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	#################################################################################
28		284
29	=back	285	=back
30		286
31	=head2 DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
32		288
33	=over 4	289	=over 4
34		290
		291	=item $AnyEvent::DNS::EDNS0
		292
		293	This variable decides whether dns_pack automatically enables EDNS0
		294	support. By default, this is disabled (C<0>), unless overridden by
		295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
		296	EDNS0 in all requests.
		297
35	=cut	298	=cut
		299
		300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0}*1; # set to 1 to enable (partial) edns0
36		301
37	our %opcode_id = (	302	our %opcode_id = (
38	query => 0,	303	query => 0,
39	iquery => 1,	304	iquery => 1,
40	status => 2,	305	status => 2,
		306	notify => 4,
		307	update => 5,
41	map +($_ => $_), 3..15	308	map +($_ => $_), 3, 6..15
42	);	309	);
43		310
44	our %opcode_str = reverse %opcode_id;	311	our %opcode_str = reverse %opcode_id;
45		312
46	our %rcode_id = (	313	our %rcode_id = (
47	ok => 0,	314	noerror => 0,
48	formerr => 1,	315	formerr => 1,
49	servfail => 2,	316	servfail => 2,
50	nxdomain => 3,	317	nxdomain => 3,
51	notimp => 4,	318	notimp => 4,
52	refused => 5,	319	refused => 5,
		320	yxdomain => 6, # Name Exists when it should not [RFC 2136]
		321	yxrrset => 7, # RR Set Exists when it should not [RFC 2136]
		322	nxrrset => 8, # RR Set that should exist does not [RFC 2136]
		323	notauth => 9, # Server Not Authoritative for zone [RFC 2136]
		324	notzone => 10, # Name not contained in zone [RFC 2136]
		325	# EDNS0 16 BADVERS Bad OPT Version [RFC 2671]
		326	# EDNS0 16 BADSIG TSIG Signature Failure [RFC 2845]
		327	# EDNS0 17 BADKEY Key not recognized [RFC 2845]
		328	# EDNS0 18 BADTIME Signature out of time window [RFC 2845]
		329	# EDNS0 19 BADMODE Bad TKEY Mode [RFC 2930]
		330	# EDNS0 20 BADNAME Duplicate key name [RFC 2930]
		331	# EDNS0 21 BADALG Algorithm not supported [RFC 2930]
53	map +($_ => $_), 6..15	332	map +($_ => $_), 11..15
54	);	333	);
55		334
56	our %rcode_str = reverse %rcode_id;	335	our %rcode_str = reverse %rcode_id;
57		336
58	our %type_id = (	337	our %type_id = (
…		…
72	minfo => 14,	351	minfo => 14,
73	mx => 15,	352	mx => 15,
74	txt => 16,	353	txt => 16,
75	aaaa => 28,	354	aaaa => 28,
76	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
		357	dname => 39, # rfc2672
		358	opt => 41,
		359	spf => 99,
		360	tkey => 249,
		361	tsig => 250,
		362	ixfr => 251,
77	axfr => 252,	363	axfr => 252,
78	mailb => 253,	364	mailb => 253,
79	"*" => 255,	365	"*" => 255,
80	);	366	);
81		367
82	our %type_str = reverse %type_id;	368	our %type_str = reverse %type_id;
83		369
84	our %class_id = (	370	our %class_id = (
85	in => 1,	371	in => 1,
86	ch => 3,	372	ch => 3,
87	hs => 4,	373	hs => 4,
		374	none => 254,
88	"*" => 255,	375	"*" => 255,
89	);	376	);
90		377
91	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
92		379
93	# names MUST have a trailing dot
94	sub _enc_qname($) {	380	sub _enc_name($) {
95	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
96	}	382	}
97		383
98	sub _enc_qd() {	384	sub _enc_qd() {
99	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
100	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
101	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
102	}	388	}
103		389
104	sub _enc_rr() {	390	sub _enc_rr() {
105	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
106	}	392	}
107		393
108	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
109		395
110	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
111	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
112		398
113	Resource records are not yet encodable.	399	Resource records are not yet encodable.
114		400
115	Examples:	401	Examples:
116		402
117	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
118	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
119		405
120	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
121		407
122	{	408	{
123	id => 10000,	409	id => 10000,
124	op => "query",	410	op => "query",
125	rc => "nxdomain",	411	rc => "nxdomain",
126		412
127	# flags	413	# flags
128	qr => 1,	414	qr => 1,
129	aa => 0,	415	aa => 0,
130	tc => 0,	416	tc => 0,
131	rd => 0,	417	rd => 0,
132	ra => 0,	418	ra => 0,
133		419	ad => 0,
		420	cd => 0,
		421
134	qd => [@rr], # query section	422	qd => [@rr], # query section
135	an => [@rr], # answer section	423	an => [@rr], # answer section
136	ns => [@rr], # authority section	424	ns => [@rr], # authority section
137	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
138	}	426	}
139		427
140	=cut	428	=cut
141		429
142	sub dns_pack($) {	430	sub dns_pack($) {
143	my ($req) = @_;	431	my ($req) = @_;
144		432
145	pack "nn nnnn a* a* a* a*",	433	pack "nn nnnn a* a* a* a* a*",
146	$req->{id},	434	$req->{id},
147		435
148	! !$req->{qr} * 0x8000	436	! !$req->{qr} * 0x8000
149	+ $opcode_id{$req->{op}} * 0x0800	437	+ $opcode_id{$req->{op}} * 0x0800
150	+ ! !$req->{aa} * 0x0400	438	+ ! !$req->{aa} * 0x0400
151	+ ! !$req->{tc} * 0x0200	439	+ ! !$req->{tc} * 0x0200
152	+ ! !$req->{rd} * 0x0100	440	+ ! !$req->{rd} * 0x0100
153	+ ! !$req->{ra} * 0x0080	441	+ ! !$req->{ra} * 0x0080
		442	+ ! !$req->{ad} * 0x0020
		443	+ ! !$req->{cd} * 0x0010
154	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
155		445
156	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
157	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
158	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
159	scalar @{ $req->{ar} \|\| [] },	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
160		450
161	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
162	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
163	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
164	(join "", map _enc_rr, @{ $req->{ar} \|\| [] });	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
		455
		456	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
165	}	457	}
166		458
167	our $ofs;	459	our $ofs;
168	our $pkt;	460	our $pkt;
169		461
170	# bitches	462	# bitches
171	sub _dec_qname {	463	sub _dec_name {
172	my @res;	464	my @res;
173	my $redir;	465	my $redir;
174	my $ptr = $ofs;	466	my $ptr = $ofs;
175	my $cnt;	467	my $cnt;
176		468
177	while () {	469	while () {
178	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
179		471
180	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
181		473
182	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
183	$ptr++;	475	$ptr++;
184	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
185	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
186	} elsif ($len) {	478	} elsif ($len) {
187	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
192	}	484	}
193	}	485	}
194	}	486	}
195		487
196	sub _dec_qd {	488	sub _dec_qd {
197	my $qname = _dec_qname;	489	my $qname = _dec_name;
198	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
199	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
200	}	492	}
201		493
202	our %dec_rr = (	494	our %dec_rr = (
203	1 => sub { Socket::inet_ntoa $_ }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
204	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
205	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
206	6 => sub {	498	6 => sub {
207	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
208	my $mname = _dec_qname;	500	my $mname = _dec_name;
209	my $rname = _dec_qname;	501	my $rname = _dec_name;
210	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
211	}, # soa	503	}, # soa
212	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
213	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
214	13 => sub { unpack "C/a C/a", $_ },	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
215	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
216	16 => sub { unpack "C/a", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
217	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	509	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
218	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
		518	99 => sub { unpack "(C/a)", $_ }, # spf
219	);	519	);
220		520
221	sub _dec_rr {	521	sub _dec_rr {
222	my $qname = _dec_qname;	522	my $name = _dec_name;
223		523
224	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;
225	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
226		526
227	[	527	[
228	$qname,	528	$name,
229	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
230	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
231	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
232	]	532	]
233	}	533	}
…		…
236		536
237	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
238		538
239	Examples:	539	Examples:
240		540
241	# a non-successful reply	541	# an unsuccessful reply
242	{	542	{
243	'qd' => [	543	'qd' => [
244	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
245	],	545	],
246	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
247	'ar' => [],	547	'ar' => [],
248	'ns' => [	548	'ns' => [
249	[	549	[
250	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
251	'soa',	551	'soa',
252	'in',	552	'in',
253	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
254	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
255	2008052201,	555	2008052201, 10800, 1800, 2592000, 86400
256	10800,
257	1800,
258	2592000,
259	86400
260	]	556	]
261	],	557	],
262	'tc' => '',	558	'tc' => '',
263	'ra' => 1,	559	'ra' => 1,
264	'qr' => 1,	560	'qr' => 1,
265	'id' => 45915,	561	'id' => 45915,
266	'aa' => '',	562	'aa' => '',
267	'an' => [],	563	'an' => [],
268	'rd' => 1,	564	'rd' => 1,
269	'op' => 'query'	565	'op' => 'query'
270	}	566	}
271		567
272	# a successful reply	568	# a successful reply
273		569
274	{	570	{
275	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
276	'rc' => 0,	572	'rc' => 0,
277	'ar' => [	573	'ar' => [
278	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
279	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
280	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
281	],	577	],
282	'ns' => [	578	'ns' => [
283	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
284	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
285	],	581	],
286	'tc' => '',	582	'tc' => '',
287	'ra' => 1,	583	'ra' => 1,
288	'qr' => 1,	584	'qr' => 1,
289	'id' => 64265,	585	'id' => 64265,
290	'aa' => '',	586	'aa' => '',
291	'an' => [	587	'an' => [
292	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
293	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
294	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
295	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
296	],	592	],
297	'rd' => 1,	593	'rd' => 1,
298	'op' => 0	594	'op' => 0
299	}	595	}
300		596
301	=cut	597	=cut
302		598
303	sub dns_unpack($) {	599	sub dns_unpack($) {
304	local $pkt = shift;	600	local $pkt = shift;
…		…
312	qr => ! ! ($flags & 0x8000),	608	qr => ! ! ($flags & 0x8000),
313	aa => ! ! ($flags & 0x0400),	609	aa => ! ! ($flags & 0x0400),
314	tc => ! ! ($flags & 0x0200),	610	tc => ! ! ($flags & 0x0200),
315	rd => ! ! ($flags & 0x0100),	611	rd => ! ! ($flags & 0x0100),
316	ra => ! ! ($flags & 0x0080),	612	ra => ! ! ($flags & 0x0080),
		613	ad => ! ! ($flags & 0x0020),
		614	cd => ! ! ($flags & 0x0010),
317	op => $opcode_str{($flags & 0x001e) >> 11},	615	op => $opcode_str{($flags & 0x001e) >> 11},
318	rc => $rcode_str{($flags & 0x000f)},	616	rc => $rcode_str{($flags & 0x000f)},
319		617
320	qd => [map _dec_qd, 1 .. $qd],	618	qd => [map _dec_qd, 1 .. $qd],
321	an => [map _dec_rr, 1 .. $an],	619	an => [map _dec_rr, 1 .. $an],
…		…
328		626
329	=back	627	=back
330		628
331	=head2 THE AnyEvent::DNS RESOLVER CLASS	629	=head2 THE AnyEvent::DNS RESOLVER CLASS
332		630
333	This is the class which deos the actual protocol work.	631	This is the class which does the actual protocol work.
334		632
335	=over 4	633	=over 4
336		634
337	=cut	635	=cut
338		636
…		…
357		655
358	our $RESOLVER;	656	our $RESOLVER;
359		657
360	sub resolver() {	658	sub resolver() {
361	$RESOLVER \|\| do {	659	$RESOLVER \|\| do {
362	$RESOLVER = new AnyEvent::DNS;	660	$RESOLVER = new AnyEvent::DNS untaint => 1;
363	$RESOLVER->load_resolv_conf;	661	$RESOLVER->os_config;
364	$RESOLVER	662	$RESOLVER
365	}	663	}
366	}	664	}
367		665
368	=item $resolver = new AnyEvent::DNS key => value...	666	=item $resolver = new AnyEvent::DNS key => value...
369		667
370	Creates and returns a new resolver. It only supports UDP, so make sure	668	Creates and returns a new resolver.
371	your answer sections fit into a DNS packet.
372		669
373	The following options are supported:	670	The following options are supported:
374		671
375	=over 4	672	=over 4
376		673
377	=item server => [...]	674	=item server => [...]
378		675
379	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
380	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).
381		679
382	=item timeout => [...]	680	=item timeout => [...]
383		681
384	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
385	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,
…		…
394	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
395	tries to resolve the name without any suffixes first.	693	tries to resolve the name without any suffixes first.
396		694
397	=item max_outstanding => $integer	695	=item max_outstanding => $integer
398		696
399	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
400	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>
401	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,
402	until some other requests have been resolved.	700	then the additional requests will be queued until some other requests have
		701	been resolved.
		702
		703	=item reuse => $seconds
		704
		705	The number of seconds (default: C<300>) that a query id cannot be re-used
		706	after a timeout. If there was no time-out then query ids can be reused
		707	immediately.
		708
		709	=item untaint => $boolean
		710
		711	When true, then the resolver will automatically untaint results, and might
		712	also ignore certain environment variables.
403		713
404	=back	714	=back
405		715
406	=cut	716	=cut
407		717
408	sub new {	718	sub new {
409	my ($class, %arg) = @_;	719	my ($class, %arg) = @_;
410		720
411	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
412	or Carp::croak "socket: $!";
413
414	AnyEvent::Util::fh_nonblocking $fh, 1;
415
416	my $self = bless {	721	my $self = bless {
417	server => [v127.0.0.1],	722	server => [],
418	timeout => [2, 5, 5],	723	timeout => [2, 5, 5],
419	search => [],	724	search => [],
420	ndots => 1,	725	ndots => 1,
421	max_outstanding => 10,	726	max_outstanding => 10,
422	reuse => 300, # reuse id's after 5 minutes only, if possible	727	reuse => 300,
423	%arg,	728	%arg,
424	fh => $fh,
425	reuse_q => [],	729	reuse_q => [],
426	}, $class;	730	}, $class;
427		731
428	# search should default to gethostname's domain	732	# search should default to gethostname's domain
429	# but perl lacks a good posix module	733	# but perl lacks a good posix module
430		734
		735	# try to create an ipv4 and an ipv6 socket
		736	# only fail when we cannot create either
		737	my $got_socket;
		738
431	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;
432	$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";
433		767
434	$self->_compile;	768	$self->_compile;
435		769
436	$self	770	$self
437	}	771	}
438		772
439	=item $resolver->parse_resolv_conv ($string)	773	=item $resolver->parse_resolv_conv ($string)
440		774
441	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
442	directives are supported:	776	directives are supported (but not necessarily implemented).
443		777
444	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	778	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
445	C<options> (C<timeout>, C<attempts>, C<ndots>).	779	C<options> (C<timeout>, C<attempts>, C<ndots>).
446		780
447	Everything else is silently ignored.	781	Everything else is silently ignored.
…		…
459	for (split /\n/, $resolvconf) {	793	for (split /\n/, $resolvconf) {
460	if (/^\s*#/) {	794	if (/^\s*#/) {
461	# comment	795	# comment
462	} elsif (/^\snameserver\s+(\S+)\s$/i) {	796	} elsif (/^\snameserver\s+(\S+)\s$/i) {
463	my $ip = $1;	797	my $ip = $1;
464	if (AnyEvent::Util::dotted_quad $ip) {	798	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
465	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	799	push @{ $self->{server} }, $ipn;
466	} else {	800	} else {
467	warn "nameserver $ip invalid and ignored\n";	801	warn "nameserver $ip invalid and ignored\n";
468	}	802	}
469	} elsif (/^\sdomain\s+(\S)\s+$/i) {	803	} elsif (/^\sdomain\s+(\S)\s+$/i) {
470	$self->{search} = [$1];	804	$self->{search} = [$1];
…		…
491	if $attempts;	825	if $attempts;
492		826
493	$self->_compile;	827	$self->_compile;
494	}	828	}
495		829
496	=item $resolver->load_resolv_conf	830	=item $resolver->os_config
497		831
498	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
499	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.
500		835
501	=cut	836	=cut
502		837
503	sub load_resolv_conf {	838	sub os_config {
504	my ($self) = @_;	839	my ($self) = @_;
505		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
506	open my $fh, "</etc/resolv.conf"	890	if (open my $fh, "</etc/resolv.conf") {
507	or return;
508
509	local $/;	891	local $/;
510	$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;
511	}	923	}
512		924
513	sub _compile {	925	sub _compile {
514	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	}
515		935
516	my @retry;	936	my @retry;
517		937
518	for my $timeout (@{ $self->{timeout} }) {	938	for my $timeout (@{ $self->{timeout} }) {
519	for my $server (@{ $self->{server} }) {	939	for my $server (@{ $self->{server} }) {
…		…
522	}	942	}
523		943
524	$self->{retry} = \@retry;	944	$self->{retry} = \@retry;
525	}	945	}
526		946
		947	sub _feed {
		948	my ($self, $res) = @_;
		949
		950	($res) = $res =~ /^(.*)$/s
		951	if AnyEvent::TAINT && $self->{untaint};
		952
		953	$res = dns_unpack $res
		954	or return;
		955
		956	my $id = $self->{id}{$res->{id}};
		957
		958	return unless ref $id;
		959
		960	$NOW = time;
		961	$id->[1]->($res);
		962	}
		963
527	sub _recv {	964	sub _recv {
528	my ($self) = @_;	965	my ($self, $pkt, $peer) = @_;
529		966
530	while (my $peer = recv $self->{fh}, my $res, 1024, 0) {	967	# we ignore errors (often one gets port unreachable, but there is
		968	# no good way to take advantage of that.
		969
531	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	970	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
532		971
533	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	972	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
534		973
535	$res = dns_unpack $res	974	$self->_feed ($pkt);
536	or return;
537
538	my $id = $self->{id}{$res->{id}};
539
540	return unless ref $id;
541
542	$NOW = time;
543	$id->[1]->($res);
544	}
545	}	975	}
546		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
547	sub _exec {	994	sub _exec {
548	my ($self, $req, $retry) = @_;	995	my ($self, $req) = @_;
549		996
		997	my $retry; # of retries
		998	my $do_retry;
		999
		1000	$do_retry = sub {
550	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
551	my ($server, $timeout) = @$retry_cfg;	1008	my ($server, $timeout) = @$retry_cfg;
552		1009
553	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1010	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
554	$NOW = time;	1011	$NOW = time;
555		1012
556	# timeout, try next	1013	# timeout, try next
557	$self->_exec ($req, $retry + 1);	1014	&$do_retry if $do_retry;
558	}), sub {	1015	}), sub {
559	my ($res) = @_;	1016	my ($res) = @_;
560		1017
		1018	if ($res->{tc}) {
		1019	# success, but truncated, so use tcp
		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
		1023	my ($fh) = @_
		1024	or return &$do_retry;
		1025
		1026	my $handle; $handle = new AnyEvent::Handle
		1027	fh => $fh,
		1028	timeout => $timeout,
		1029	on_error => sub {
		1030	undef $handle;
		1031	return unless $do_retry; # some other request could have invalidated us already
		1032	# failure, try next
		1033	&$do_retry;
		1034	};
		1035
		1036	$handle->push_write (pack "n/a", $req->[0]);
		1037	$handle->push_read (chunk => 2, sub {
		1038	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1039	undef $handle;
		1040	$self->_feed ($_[1]);
		1041	});
		1042	});
		1043
		1044	}, sub { $timeout });
		1045
		1046	} else {
561	# success	1047	# success
562	$self->{id}{$req->[2]} = 1;	1048	$self->_free_id ($req->[2], $retry > 1);
563	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1049	undef $do_retry; return $req->[1]->($res);
564	--$self->{outstanding};	1050	}
565	$self->_scheduler;
566
567	$req->[1]->($res);
568	}];	1051	}];
		1052
		1053	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
569		1054
570	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1055	my $fh = AF_INET == Socket::sockaddr_family ($sa)
571	} else {	1056	? $self->{fh4} : $self->{fh6}
572	# failure	1057	or return &$do_retry;
573	$self->{id}{$req->[2]} = 1;
574	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
575	--$self->{outstanding};
576	$self->_scheduler;
577		1058
578	$req->[1]->();	1059	send $fh, $req->[0], 0, $sa;
579	}	1060	};
		1061
		1062	&$do_retry;
580	}	1063	}
581		1064
582	sub _scheduler {	1065	sub _scheduler {
583	my ($self) = @_;	1066	my ($self) = @_;
584		1067
		1068	no strict 'refs';
		1069
585	$NOW = time;	1070	$NOW = time;
586		1071
587	# first clear id reuse queue	1072	# first clear id reuse queue
588	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1073	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
589	while @{ $self->{reuse_q} } && $self->{reuse_q}[0] <= $NOW;	1074	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;
590		1075
591	while ($self->{outstanding} < $self->{max_outstanding}) {	1076	while ($self->{outstanding} < $self->{max_outstanding}) {
592	my $req = shift @{ $self->{queue} }	1077
		1078	if (@{ $self->{reuse_q} } >= 30000) {
		1079	# we ran out of ID's, wait a bit
		1080	$self->{reuse_to} \|\|= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub {
		1081	delete $self->{reuse_to};
		1082	$self->_scheduler;
		1083	});
593	or last;	1084	last;
594
595	while () {
596	$req->[2] = int rand 65536;
597	last unless exists $self->{id}{$req->[2]};
598	}	1085	}
599		1086
		1087	if (my $req = shift @{ $self->{queue} }) {
		1088	# found a request in the queue, execute it
		1089	while () {
		1090	$req->[2] = int rand 65536;
		1091	last unless exists $self->{id}{$req->[2]};
		1092	}
		1093
		1094	++$self->{outstanding};
600	$self->{id}{$req->[2]} = 1;	1095	$self->{id}{$req->[2]} = 1;
601	substr $req->[0], 0, 2, pack "n", $req->[2];	1096	substr $req->[0], 0, 2, pack "n", $req->[2];
602		1097
603	++$self->{outstanding};
604	$self->_exec ($req, 0);	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;
		1107	}
605	}	1108	}
606	}	1109	}
607		1110
608	=item $resolver->request ($req, $cb->($res))	1111	=item $resolver->request ($req, $cb->($res))
609		1112
		1113	This is the main low-level workhorse for sending DNS requests.
		1114
610	Sends a single request (a hash-ref formated as specified for	1115	This function sends a single request (a hash-ref formated as specified
611	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
612	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
613	was received, or no arguments on timeout.	1121	received, or no arguments in case none of the servers answered.
614		1122
615	=cut	1123	=cut
616		1124
617	sub request($$) {	1125	sub request($$) {
618	my ($self, $req, $cb) = @_;	1126	my ($self, $req, $cb) = @_;
619		1127
620	push @{ $self->{queue} }, [dns_pack $req, $cb];	1128	push @{ $self->{queue} }, [dns_pack $req, $cb];
621	$self->_scheduler;	1129	$self->_scheduler;
622	}	1130	}
623		1131
624	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1132	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
625		1133
626	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1134	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
627	qtype of "*" is supported and means "any").	1135
		1136	A C<$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<$qtype> of "*" is supported and means
		1140	"any" record type.
628		1141
629	The callback will be invoked with a list of matching result records or	1142	The callback will be invoked with a list of matching result records or
630	none on any error or if the name could not be found.	1143	none on any error or if the name could not be found.
631		1144
632	CNAME chains (although illegal) are followed up to a length of 8.	1145	CNAME chains (although illegal) are followed up to a length of 10.
633		1146
		1147	The callback will be invoked with arraryefs of the form C<[$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
634	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
635	supporting recursive queries, will not do any recursive queries itself and	1159	supporting recursive queries, will not do any recursive queries itself and
636	is not secure when used against an untrusted name server.	1160	is not secure when used against an untrusted name server.
637		1161
638	The following options are supported:	1162	The following options are supported:
639		1163
…		…
641		1165
642	=item search => [$suffix...]	1166	=item search => [$suffix...]
643		1167
644	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
645	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
646	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1170	C<ndots> and C<search> values define its value (depending on C<ndots>, the
647	then the searchlist will be ignored.	1171	empty suffix will be prepended or appended to that C<search> value). If
		1172	the C<$qname> ends in a dot, then the searchlist will be ignored.
648		1173
649	=item accept => [$type...]	1174	=item accept => [$type...]
650		1175
651	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
652	accepted and returned. The default includes the C<$qtype> and nothing	1177	accepted and returned. The default includes the C<$qtype> and nothing
653	else.	1178	else. If this list includes C<cname>, then CNAME-chains will not be
		1179	followed (because you asked for the CNAME record).
654		1180
655	=item class => "class"	1181	=item class => "class"
656		1182
657	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
658	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.
659		1185
660	=back	1186	=back
661		1187
662	Examples:	1188	Examples:
663		1189
664	$res->resolve ("ruth.plan9.de", "a", sub {	1190	# full example, you can paste this into perl:
665	warn Dumper [@_];	1191	use Data::Dumper;
666	});	1192	use AnyEvent::DNS;
		1193	AnyEvent::DNS::resolver->resolve (
		1194	"google.com", "*", my $cv = AnyEvent->condvar);
		1195	warn Dumper [$cv->recv];
667		1196
		1197	# shortened result:
668	[	1198	# [
		1199	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1200	# 2008052701, 7200, 1800, 1209600, 300 ],
669	[	1201	# [
670	'ruth.schmorp.de',	1202	# 'google.com', 'txt', 'in',
671	'a',	1203	# 'v=spf1 include:_netblocks.google.com ~all'
672	'in',	1204	# ],
673	'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' ],
674	]	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' ]
675	]	1216	# ]
676		1217
		1218	# resolve any records, but return only a and aaaa records:
677	$res->resolve ("test1.laendle", "*",	1219	$res->resolve ("test1.laendle", "*",
678	accept => ["a", "aaaa"],	1220	accept => ["a", "aaaa"],
679	sub {	1221	sub {
680	warn Dumper [@_];	1222	warn Dumper [@_];
681	}	1223	}
682	);	1224	);
683		1225
684	[	1226	# result:
685	[	1227	# [
686	'test1.laendle',	1228	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
687	'a',	1229	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
688	'in',
689	'10.0.0.255'
690	],
691	[
692	'test1.laendle',
693	'aaaa',
694	'in',
695	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
696	]	1230	# ]
697	]
698		1231
699	=cut	1232	=cut
700		1233
701	sub resolve($%) {	1234	sub resolve($%) {
702	my $cb = pop;	1235	my $cb = pop;
…		…
715	my %atype = $opt{accept}	1248	my %atype = $opt{accept}
716	? map +($_ => 1), @{ $opt{accept} }	1249	? map +($_ => 1), @{ $opt{accept} }
717	: ($qtype => 1);	1250	: ($qtype => 1);
718		1251
719	# advance in searchlist	1252	# advance in searchlist
720	my $do_search; $do_search = sub {	1253	my ($do_search, $do_req);
		1254
		1255	$do_search = sub {
721	@search	1256	@search
722	or return $cb->();	1257	or (undef $do_search), (undef $do_req), return $cb->();
723		1258
724	(my $name = "$qname." . shift @search) =~ s/\.$//;	1259	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
725	my $depth = 2;	1260	my $depth = 10;
726		1261
727	# advance in cname-chain	1262	# advance in cname-chain
728	my $do_req; $do_req = sub {	1263	$do_req = sub {
729	$self->request ({	1264	$self->request ({
730	rd => 1,	1265	rd => 1,
731	qd => [[$name, $qtype, $class]],	1266	qd => [[$name, $qtype, $class]],
732	}, sub {	1267	}, sub {
733	my ($res) = @_	1268	my ($res) = @_
…		…
735		1270
736	my $cname;	1271	my $cname;
737		1272
738	while () {	1273	while () {
739	# results found?	1274	# results found?
740	my @rr = grep $_->[0] eq $name && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1275	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
741		1276
742	return $cb->(@rr)	1277	(undef $do_search), (undef $do_req), return $cb->(@rr)
743	if @rr;	1278	if @rr;
744		1279
745	# see if there is a cname we can follow	1280	# see if there is a cname we can follow
746	my @rr = grep $_->[0] eq $name && $_->[1] eq "cname", @{ $res->{an} };	1281	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
747		1282
748	if (@rr) {	1283	if (@rr) {
749	$depth--	1284	$depth--
750	or return $do_search->(); # cname chain too long	1285	or return $do_search->(); # cname chain too long
751		1286
…		…
768	};	1303	};
769		1304
770	$do_search->();	1305	$do_search->();
771	}	1306	}
772		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
773	1;	1341	1;
774		1342
775	=back	1343	=back
776		1344
777	=head1 AUTHOR	1345	=head1 AUTHOR
778		1346
779	Marc Lehmann <schmorp@schmorp.de>	1347	Marc Lehmann <schmorp@schmorp.de>
780	http://home.schmorp.de/	1348	http://home.schmorp.de/
781		1349
782	=cut	1350	=cut
783		1351

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.3 by root, Fri May 23 03:20:53 2008 UTC vs. Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.3 by root, Fri May 23 03:20:53 2008 UTC vs.
Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC