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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.4 by root, Fri May 23 04:10:40 2008 UTC vs.
Revision 1.69 by root, Thu Jul 3 02:03:33 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 ();
		37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
26		39
27	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.160;
28		41
29	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
30
31	Tries to resolve the given nodename and service name into sockaddr
32	structures usable to connect to this node and service in a
33	protocol-independent way. It works similarly to the getaddrinfo posix
34	function.
35
36	Example:
37
38	AnyEvent::DNS::addr "google.com", "http", AF_UNSPEC, SOCK_STREAM, sub { ... };
39		43
40	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
41		45
42	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).
43		51
44	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)	52	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)
45		53
46	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
47	first) list of domain names.	55	first) list of domain names.
…		…
57	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
58		66
59	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
60	of service records.	68	of service records.
61		69
62	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
63	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
64		72
65	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
66	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
67		75
68	Example:	76	Example:
69		77
70	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
71	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
72		80
73	=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)
74		93
75	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)
76	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
77		97
78	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.
79		108
80	Example:	109	Example:
81		110
82	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
83	# => f.root-servers.net	112	# => f.root-servers.net
84		113
85	=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
86		119
87	sub resolver;	120	sub resolver;
88		121
89	sub a($$) {	122	sub a($$) {
90	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
92	resolver->resolve ($domain => "a", sub {	125	resolver->resolve ($domain => "a", sub {
93	$cb->(map $_->[3], @_);	126	$cb->(map $_->[3], @_);
94	});	127	});
95	}	128	}
96		129
		130	sub aaaa($$) {
		131	my ($domain, $cb) = @_;
		132
		133	resolver->resolve ($domain => "aaaa", sub {
		134	$cb->(map $_->[3], @_);
		135	});
		136	}
		137
97	sub mx($$) {	138	sub mx($$) {
98	my ($domain, $cb) = @_;	139	my ($domain, $cb) = @_;
99		140
100	resolver->resolve ($domain => "mx", sub {	141	resolver->resolve ($domain => "mx", sub {
101	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);	142	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);
…		…
121	sub srv($$$$) {	162	sub srv($$$$) {
122	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
123		164
124	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
125	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
126	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
127	});	194	});
128	}	195	}
129		196
130	sub ptr($$) {	197	sub ptr($$) {
131	my ($ip, $cb) = @_;	198	my ($domain, $cb) = @_;
132		199
133	my $name;
134
135	if (AnyEvent::Util::dotted_quad $ip) {
136	$name = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
137	} else {
138	require Socket6;
139	$name = join ".",
140	(reverse split //,
141	unpack "H*", Socket6::inet_pton (Socket::AF_INET6, $ip)),
142	"ip6.arpa.";
143	}
144
145	resolver->resolve ($name => "ptr", sub {	200	resolver->resolve ($domain => "ptr", sub {
146	$cb->(map $_->[3], @_);	201	$cb->(map $_->[3], @_);
147	});	202	});
148	}	203	}
149		204
		205	sub any($$) {
		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	#################################################################################
		284
		285	=back
		286
150	=head2 DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
151		288
152	=over 4	289	=over 4
153		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
154	=cut	298	=cut
		299
		300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0
155		301
156	our %opcode_id = (	302	our %opcode_id = (
157	query => 0,	303	query => 0,
158	iquery => 1,	304	iquery => 1,
159	status => 2,	305	status => 2,
		306	notify => 4,
		307	update => 5,
160	map +($_ => $_), 3..15	308	map +($_ => $_), 3, 6..15
161	);	309	);
162		310
163	our %opcode_str = reverse %opcode_id;	311	our %opcode_str = reverse %opcode_id;
164		312
165	our %rcode_id = (	313	our %rcode_id = (
166	noerror => 0,	314	noerror => 0,
167	formerr => 1,	315	formerr => 1,
168	servfail => 2,	316	servfail => 2,
169	nxdomain => 3,	317	nxdomain => 3,
170	notimp => 4,	318	notimp => 4,
171	refused => 5,	319	refused => 5,
		320	yxdomain => 6, # Name Exists when it should not [RFC 2136]
		321	yxrrset => 7, # RR Set Exists when it should not [RFC 2136]
		322	nxrrset => 8, # RR Set that should exist does not [RFC 2136]
		323	notauth => 9, # Server Not Authoritative for zone [RFC 2136]
		324	notzone => 10, # Name not contained in zone [RFC 2136]
		325	# EDNS0 16 BADVERS Bad OPT Version [RFC 2671]
		326	# EDNS0 16 BADSIG TSIG Signature Failure [RFC 2845]
		327	# EDNS0 17 BADKEY Key not recognized [RFC 2845]
		328	# EDNS0 18 BADTIME Signature out of time window [RFC 2845]
		329	# EDNS0 19 BADMODE Bad TKEY Mode [RFC 2930]
		330	# EDNS0 20 BADNAME Duplicate key name [RFC 2930]
		331	# EDNS0 21 BADALG Algorithm not supported [RFC 2930]
172	map +($_ => $_), 6..15	332	map +($_ => $_), 11..15
173	);	333	);
174		334
175	our %rcode_str = reverse %rcode_id;	335	our %rcode_str = reverse %rcode_id;
176		336
177	our %type_id = (	337	our %type_id = (
…		…
191	minfo => 14,	351	minfo => 14,
192	mx => 15,	352	mx => 15,
193	txt => 16,	353	txt => 16,
194	aaaa => 28,	354	aaaa => 28,
195	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
		357	opt => 41,
		358	spf => 99,
		359	tkey => 249,
		360	tsig => 250,
		361	ixfr => 251,
196	axfr => 252,	362	axfr => 252,
197	mailb => 253,	363	mailb => 253,
198	"*" => 255,	364	"*" => 255,
199	);	365	);
200		366
201	our %type_str = reverse %type_id;	367	our %type_str = reverse %type_id;
202		368
203	our %class_id = (	369	our %class_id = (
204	in => 1,	370	in => 1,
205	ch => 3,	371	ch => 3,
206	hs => 4,	372	hs => 4,
		373	none => 254,
207	"*" => 255,	374	"*" => 255,
208	);	375	);
209		376
210	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
211		378
212	# names MUST have a trailing dot
213	sub _enc_qname($) {	379	sub _enc_name($) {
214	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
215	}	381	}
216		382
217	sub _enc_qd() {	383	sub _enc_qd() {
218	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
219	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
220	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
221	}	387	}
222		388
223	sub _enc_rr() {	389	sub _enc_rr() {
224	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
225	}	391	}
226		392
227	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
228		394
229	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	395	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
230	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
231		397
232	Resource records are not yet encodable.	398	Resource records are not yet encodable.
233		399
234	Examples:	400	Examples:
235		401
236	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
237	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
238		404
239	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
240		406
241	{	407	{
242	id => 10000,	408	id => 10000,
243	op => "query",	409	op => "query",
244	rc => "nxdomain",	410	rc => "nxdomain",
245		411
246	# flags	412	# flags
247	qr => 1,	413	qr => 1,
248	aa => 0,	414	aa => 0,
249	tc => 0,	415	tc => 0,
250	rd => 0,	416	rd => 0,
251	ra => 0,	417	ra => 0,
252		418	ad => 0,
		419	cd => 0,
		420
253	qd => [@rr], # query section	421	qd => [@rr], # query section
254	an => [@rr], # answer section	422	an => [@rr], # answer section
255	ns => [@rr], # authority section	423	ns => [@rr], # authority section
256	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
257	}	425	}
258		426
259	=cut	427	=cut
260		428
261	sub dns_pack($) {	429	sub dns_pack($) {
262	my ($req) = @_;	430	my ($req) = @_;
263		431
264	pack "nn nnnn a* a* a* a*",	432	pack "nn nnnn a* a* a* a* a*",
265	$req->{id},	433	$req->{id},
266		434
267	! !$req->{qr} * 0x8000	435	! !$req->{qr} * 0x8000
268	+ $opcode_id{$req->{op}} * 0x0800	436	+ $opcode_id{$req->{op}} * 0x0800
269	+ ! !$req->{aa} * 0x0400	437	+ ! !$req->{aa} * 0x0400
270	+ ! !$req->{tc} * 0x0200	438	+ ! !$req->{tc} * 0x0200
271	+ ! !$req->{rd} * 0x0100	439	+ ! !$req->{rd} * 0x0100
272	+ ! !$req->{ra} * 0x0080	440	+ ! !$req->{ra} * 0x0080
		441	+ ! !$req->{ad} * 0x0020
		442	+ ! !$req->{cd} * 0x0010
273	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
274		444
275	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
276	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
277	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
278	scalar @{ $req->{ar} \|\| [] },	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
279		449
280	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
281	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
282	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
283	(join "", map _enc_rr, @{ $req->{ar} \|\| [] });	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
		454
		455	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
284	}	456	}
285		457
286	our $ofs;	458	our $ofs;
287	our $pkt;	459	our $pkt;
288		460
289	# bitches	461	# bitches
290	sub _dec_qname {	462	sub _dec_name {
291	my @res;	463	my @res;
292	my $redir;	464	my $redir;
293	my $ptr = $ofs;	465	my $ptr = $ofs;
294	my $cnt;	466	my $cnt;
295		467
296	while () {	468	while () {
297	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
298		470
299	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
300		472
301	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
302	$ptr++;	474	$ptr++;
303	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
304	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
305	} elsif ($len) {	477	} elsif ($len) {
306	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
311	}	483	}
312	}	484	}
313	}	485	}
314		486
315	sub _dec_qd {	487	sub _dec_qd {
316	my $qname = _dec_qname;	488	my $qname = _dec_name;
317	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
318	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
319	}	491	}
320		492
321	our %dec_rr = (	493	our %dec_rr = (
322	1 => sub { Socket::inet_ntoa $_ }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
323	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
324	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
325	6 => sub {	497	6 => sub {
326	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
327	my $mname = _dec_qname;	499	my $mname = _dec_name;
328	my $rname = _dec_qname;	500	my $rname = _dec_name;
329	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
330	}, # soa	502	}, # soa
331	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
332	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
333	13 => sub { unpack "C/a C/a", $_ },	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
334	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
335	16 => sub { unpack "C/a", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
336	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
337	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	},
		516	99 => sub { unpack "(C/a)", $_ }, # spf
338	);	517	);
339		518
340	sub _dec_rr {	519	sub _dec_rr {
341	my $qname = _dec_qname;	520	my $name = _dec_name;
342		521
343	my ($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;
344	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
345		524
346	[	525	[
347	$qname,	526	$name,
348	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
349	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
350	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
351	]	530	]
352	}	531	}
…		…
355		534
356	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
357		536
358	Examples:	537	Examples:
359		538
360	# a non-successful reply	539	# an unsuccessful reply
361	{	540	{
362	'qd' => [	541	'qd' => [
363	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
364	],	543	],
365	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
366	'ar' => [],	545	'ar' => [],
367	'ns' => [	546	'ns' => [
368	[	547	[
369	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
370	'soa',	549	'soa',
371	'in',	550	'in',
372	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
373	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
374	2008052201,	553	2008052201, 10800, 1800, 2592000, 86400
375	10800,
376	1800,
377	2592000,
378	86400
379	]	554	]
380	],	555	],
381	'tc' => '',	556	'tc' => '',
382	'ra' => 1,	557	'ra' => 1,
383	'qr' => 1,	558	'qr' => 1,
384	'id' => 45915,	559	'id' => 45915,
385	'aa' => '',	560	'aa' => '',
386	'an' => [],	561	'an' => [],
387	'rd' => 1,	562	'rd' => 1,
388	'op' => 'query'	563	'op' => 'query'
389	}	564	}
390		565
391	# a successful reply	566	# a successful reply
392		567
393	{	568	{
394	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
395	'rc' => 0,	570	'rc' => 0,
396	'ar' => [	571	'ar' => [
397	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
398	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
399	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
400	],	575	],
401	'ns' => [	576	'ns' => [
402	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
403	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
404	],	579	],
405	'tc' => '',	580	'tc' => '',
406	'ra' => 1,	581	'ra' => 1,
407	'qr' => 1,	582	'qr' => 1,
408	'id' => 64265,	583	'id' => 64265,
409	'aa' => '',	584	'aa' => '',
410	'an' => [	585	'an' => [
411	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
412	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
413	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
414	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
415	],	590	],
416	'rd' => 1,	591	'rd' => 1,
417	'op' => 0	592	'op' => 0
418	}	593	}
419		594
420	=cut	595	=cut
421		596
422	sub dns_unpack($) {	597	sub dns_unpack($) {
423	local $pkt = shift;	598	local $pkt = shift;
…		…
431	qr => ! ! ($flags & 0x8000),	606	qr => ! ! ($flags & 0x8000),
432	aa => ! ! ($flags & 0x0400),	607	aa => ! ! ($flags & 0x0400),
433	tc => ! ! ($flags & 0x0200),	608	tc => ! ! ($flags & 0x0200),
434	rd => ! ! ($flags & 0x0100),	609	rd => ! ! ($flags & 0x0100),
435	ra => ! ! ($flags & 0x0080),	610	ra => ! ! ($flags & 0x0080),
		611	ad => ! ! ($flags & 0x0020),
		612	cd => ! ! ($flags & 0x0010),
436	op => $opcode_str{($flags & 0x001e) >> 11},	613	op => $opcode_str{($flags & 0x001e) >> 11},
437	rc => $rcode_str{($flags & 0x000f)},	614	rc => $rcode_str{($flags & 0x000f)},
438		615
439	qd => [map _dec_qd, 1 .. $qd],	616	qd => [map _dec_qd, 1 .. $qd],
440	an => [map _dec_rr, 1 .. $an],	617	an => [map _dec_rr, 1 .. $an],
…		…
447		624
448	=back	625	=back
449		626
450	=head2 THE AnyEvent::DNS RESOLVER CLASS	627	=head2 THE AnyEvent::DNS RESOLVER CLASS
451		628
452	This is the class which deos the actual protocol work.	629	This is the class which does the actual protocol work.
453		630
454	=over 4	631	=over 4
455		632
456	=cut	633	=cut
457		634
…		…
477	our $RESOLVER;	654	our $RESOLVER;
478		655
479	sub resolver() {	656	sub resolver() {
480	$RESOLVER \|\| do {	657	$RESOLVER \|\| do {
481	$RESOLVER = new AnyEvent::DNS;	658	$RESOLVER = new AnyEvent::DNS;
482	$RESOLVER->load_resolv_conf;	659	$RESOLVER->os_config;
483	$RESOLVER	660	$RESOLVER
484	}	661	}
485	}	662	}
486		663
487	=item $resolver = new AnyEvent::DNS key => value...	664	=item $resolver = new AnyEvent::DNS key => value...
488		665
489	Creates and returns a new resolver. It only supports UDP, so make sure	666	Creates and returns a new resolver.
490	your answer sections fit into a DNS packet.
491		667
492	The following options are supported:	668	The following options are supported:
493		669
494	=over 4	670	=over 4
495		671
496	=item server => [...]	672	=item server => [...]
497		673
498	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
499	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).
500		677
501	=item timeout => [...]	678	=item timeout => [...]
502		679
503	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
504	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,
…		…
513	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
514	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
515		692
516	=item max_outstanding => $integer	693	=item max_outstanding => $integer
517		694
518	Most name servers do not handle many parallel requests very well. This option	695	Most name servers do not handle many parallel requests very well. This
519	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	696	option limits the number of outstanding requests to C<$integer>
520	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,
521	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 => $seconds
		702
		703	The number of seconds (default: C<300>) that a query id cannot be re-used
		704	after a timeout. If there was no time-out then query ids can be reused
		705	immediately.
522		706
523	=back	707	=back
524		708
525	=cut	709	=cut
526		710
527	sub new {	711	sub new {
528	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
529		713
530	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
531	or Carp::croak "socket: $!";
532
533	AnyEvent::Util::fh_nonblocking $fh, 1;
534
535	my $self = bless {	714	my $self = bless {
536	server => [v127.0.0.1],	715	server => [],
537	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
538	search => [],	717	search => [],
539	ndots => 1,	718	ndots => 1,
540	max_outstanding => 10,	719	max_outstanding => 10,
541	reuse => 300, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
542	%arg,	721	%arg,
543	fh => $fh,
544	reuse_q => [],	722	reuse_q => [],
545	}, $class;	723	}, $class;
546		724
547	# search should default to gethostname's domain	725	# search should default to gethostname's domain
548	# but perl lacks a good posix module	726	# but perl lacks a good posix module
549		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
550	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;
551	$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";
552		760
553	$self->_compile;	761	$self->_compile;
554		762
555	$self	763	$self
556	}	764	}
557		765
558	=item $resolver->parse_resolv_conv ($string)	766	=item $resolver->parse_resolv_conv ($string)
559		767
560	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
561	directives are supported:	769	directives are supported (but not necessarily implemented).
562		770
563	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	771	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
564	C<options> (C<timeout>, C<attempts>, C<ndots>).	772	C<options> (C<timeout>, C<attempts>, C<ndots>).
565		773
566	Everything else is silently ignored.	774	Everything else is silently ignored.
…		…
578	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
579	if (/^\s*#/) {	787	if (/^\s*#/) {
580	# comment	788	# comment
581	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
582	my $ip = $1;	790	my $ip = $1;
583	if (AnyEvent::Util::dotted_quad $ip) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
584	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	792	push @{ $self->{server} }, $ipn;
585	} else {	793	} else {
586	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
587	}	795	}
588	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
589	$self->{search} = [$1];	797	$self->{search} = [$1];
…		…
610	if $attempts;	818	if $attempts;
611		819
612	$self->_compile;	820	$self->_compile;
613	}	821	}
614		822
615	=item $resolver->load_resolv_conf	823	=item $resolver->os_config
616		824
617	Tries to load and parse F</etc/resolv.conf>. If there will ever be windows	825	Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various
618	support, then this function will do the right thing under windows, too.	826	egregious hacks on windows to force the DNS servers and searchlist out of the system.
619		827
620	=cut	828	=cut
621		829
622	sub load_resolv_conf {	830	sub os_config {
623	my ($self) = @_;	831	my ($self) = @_;
624		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
625	open my $fh, "</etc/resolv.conf"	882	if (open my $fh, "</etc/resolv.conf") {
626	or return;
627
628	local $/;	883	local $/;
629	$self->parse_resolv_conf (<$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;
630	}	915	}
631		916
632	sub _compile {	917	sub _compile {
633	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	}
634		927
635	my @retry;	928	my @retry;
636		929
637	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
638	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
641	}	934	}
642		935
643	$self->{retry} = \@retry;	936	$self->{retry} = \@retry;
644	}	937	}
645		938
		939	sub _feed {
		940	my ($self, $res) = @_;
		941
		942	$res = dns_unpack $res
		943	or return;
		944
		945	my $id = $self->{id}{$res->{id}};
		946
		947	return unless ref $id;
		948
		949	$NOW = time;
		950	$id->[1]->($res);
		951	}
		952
646	sub _recv {	953	sub _recv {
647	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
648		955
649	while (my $peer = recv $self->{fh}, my $res, 1024, 0) {	956	# we ignore errors (often one gets port unreachable, but there is
		957	# no good way to take advantage of that.
		958
650	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
651		960
652	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
653		962
654	$res = dns_unpack $res	963	$self->_feed ($pkt);
655	or return;
656
657	my $id = $self->{id}{$res->{id}};
658
659	return unless ref $id;
660
661	$NOW = time;
662	$id->[1]->($res);
663	}
664	}	964	}
665		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	$self->_scheduler;
		980	}
		981
		982	# execute a single request, involves sending it with timeouts to multiple servers
666	sub _exec {	983	sub _exec {
667	my ($self, $req, $retry) = @_;	984	my ($self, $req) = @_;
668		985
		986	my $retry; # of retries
		987	my $do_retry;
		988
		989	$do_retry = sub {
669	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 $req->[1]->();
		995	};
		996
670	my ($server, $timeout) = @$retry_cfg;	997	my ($server, $timeout) = @$retry_cfg;
671		998
672	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
673	$NOW = time;	1000	$NOW = time;
674		1001
675	# timeout, try next	1002	# timeout, try next
676	$self->_exec ($req, $retry + 1);	1003	&$do_retry;
677	}), sub {	1004	}), sub {
678	my ($res) = @_;	1005	my ($res) = @_;
679		1006
		1007	if ($res->{tc}) {
		1008	# success, but truncated, so use tcp
		1009	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1010	return unless $do_retry; # some other request could have invalidated us already
		1011
		1012	my ($fh) = @_
		1013	or return &$do_retry;
		1014
		1015	my $handle; $handle = new AnyEvent::Handle
		1016	fh => $fh,
		1017	timeout => $timeout,
		1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
		1021	# failure, try next
		1022	&$do_retry;
		1023	};
		1024
		1025	$handle->push_write (pack "n/a", $req->[0]);
		1026	$handle->push_read (chunk => 2, sub {
		1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
		1029	$self->_feed ($_[1]);
		1030	});
		1031	});
		1032
		1033	}, sub { $timeout });
		1034
		1035	} else {
680	# success	1036	# success
681	$self->{id}{$req->[2]} = 1;	1037	$self->_free_id ($req->[2], $retry > 1);
682	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1038	undef $do_retry; return $req->[1]->($res);
683	--$self->{outstanding};	1039	}
684	$self->_scheduler;
685
686	$req->[1]->($res);
687	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
688		1043
689	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
690	} else {	1045	? $self->{fh4} : $self->{fh6}
691	# failure	1046	or return &$do_retry;
692	$self->{id}{$req->[2]} = 1;
693	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
694	--$self->{outstanding};
695	$self->_scheduler;
696		1047
697	$req->[1]->();	1048	send $fh, $req->[0], 0, $sa;
698	}	1049	};
		1050
		1051	&$do_retry;
699	}	1052	}
700		1053
701	sub _scheduler {	1054	sub _scheduler {
702	my ($self) = @_;	1055	my ($self) = @_;
703		1056
		1057	no strict 'refs';
		1058
704	$NOW = time;	1059	$NOW = time;
705		1060
706	# first clear id reuse queue	1061	# first clear id reuse queue
707	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
708	while @{ $self->{reuse_q} } && $self->{reuse_q}[0] <= $NOW;	1063	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;
709		1064
710	while ($self->{outstanding} < $self->{max_outstanding}) {	1065	while ($self->{outstanding} < $self->{max_outstanding}) {
711	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	});
712	or last;	1073	last;
713
714	while () {
715	$req->[2] = int rand 65536;
716	last unless exists $self->{id}{$req->[2]};
717	}	1074	}
718		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};
719	$self->{id}{$req->[2]} = 1;	1084	$self->{id}{$req->[2]} = 1;
720	substr $req->[0], 0, 2, pack "n", $req->[2];	1085	substr $req->[0], 0, 2, pack "n", $req->[2];
721		1086
722	++$self->{outstanding};
723	$self->_exec ($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	}
724	}	1097	}
725	}	1098	}
726		1099
727	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
728		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
729	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
730	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
731	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
732	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
733		1111
734	=cut	1112	=cut
735		1113
736	sub request($$) {	1114	sub request($$) {
737	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
…		…
740	$self->_scheduler;	1118	$self->_scheduler;
741	}	1119	}
742		1120
743	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))
744		1122
745	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>.
746	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.
747		1130
748	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
749	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.
750		1133
751	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.
752		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
753	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
754	supporting recursive queries, will not do any recursive queries itself and	1150	supporting recursive queries, will not do any recursive queries itself and
755	is not secure when used against an untrusted name server.	1151	is not secure when used against an untrusted name server.
756		1152
757	The following options are supported:	1153	The following options are supported:
758		1154
…		…
760		1156
761	=item search => [$suffix...]	1157	=item search => [$suffix...]
762		1158
763	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
764	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
765	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1161	C<ndots> and C<search> values define its value (depending on C<ndots>, the
766	then the searchlist will be ignored.	1162	empty suffix will be prepended or appended to that C<search> value). If
		1163	the C<$qname> ends in a dot, then the searchlist will be ignored.
767		1164
768	=item accept => [$type...]	1165	=item accept => [$type...]
769		1166
770	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
771	accepted and returned. The default includes the C<$qtype> and nothing	1168	accepted and returned. The default includes the C<$qtype> and nothing
772	else.	1169	else. If this list includes C<cname>, then CNAME-chains will not be
		1170	followed (because you asked for the CNAME record).
773		1171
774	=item class => "class"	1172	=item class => "class"
775		1173
776	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
777	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.
778		1176
779	=back	1177	=back
780		1178
781	Examples:	1179	Examples:
782		1180
783	$res->resolve ("ruth.plan9.de", "a", sub {	1181	# full example, you can paste this into perl:
784	warn Dumper [@_];	1182	use Data::Dumper;
785	});	1183	use AnyEvent::DNS;
		1184	AnyEvent::DNS::resolver->resolve (
		1185	"google.com", "*", my $cv = AnyEvent->condvar);
		1186	warn Dumper [$cv->recv];
786		1187
		1188	# shortened result:
787	[	1189	# [
		1190	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1191	# 2008052701, 7200, 1800, 1209600, 300 ],
788	[	1192	# [
789	'ruth.schmorp.de',	1193	# 'google.com', 'txt', 'in',
790	'a',	1194	# 'v=spf1 include:_netblocks.google.com ~all'
791	'in',	1195	# ],
792	'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' ],
793	]	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' ]
794	]	1207	# ]
795		1208
		1209	# resolve any records, but return only a and aaaa records:
796	$res->resolve ("test1.laendle", "*",	1210	$res->resolve ("test1.laendle", "*",
797	accept => ["a", "aaaa"],	1211	accept => ["a", "aaaa"],
798	sub {	1212	sub {
799	warn Dumper [@_];	1213	warn Dumper [@_];
800	}	1214	}
801	);	1215	);
802		1216
803	[	1217	# result:
804	[	1218	# [
805	'test1.laendle',	1219	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
806	'a',	1220	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
807	'in',
808	'10.0.0.255'
809	],
810	[
811	'test1.laendle',
812	'aaaa',
813	'in',
814	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
815	]	1221	# ]
816	]
817		1222
818	=cut	1223	=cut
819		1224
820	sub resolve($%) {	1225	sub resolve($%) {
821	my $cb = pop;	1226	my $cb = pop;
…		…
834	my %atype = $opt{accept}	1239	my %atype = $opt{accept}
835	? map +($_ => 1), @{ $opt{accept} }	1240	? map +($_ => 1), @{ $opt{accept} }
836	: ($qtype => 1);	1241	: ($qtype => 1);
837		1242
838	# advance in searchlist	1243	# advance in searchlist
839	my $do_search; $do_search = sub {	1244	my ($do_search, $do_req);
		1245
		1246	$do_search = sub {
840	@search	1247	@search
841	or return $cb->();	1248	or (undef $do_search), (undef $do_req), return $cb->();
842		1249
843	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1250	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
844	my $depth = 2;	1251	my $depth = 10;
845		1252
846	# advance in cname-chain	1253	# advance in cname-chain
847	my $do_req; $do_req = sub {	1254	$do_req = sub {
848	$self->request ({	1255	$self->request ({
849	rd => 1,	1256	rd => 1,
850	qd => [[$name, $qtype, $class]],	1257	qd => [[$name, $qtype, $class]],
851	}, sub {	1258	}, sub {
852	my ($res) = @_	1259	my ($res) = @_
…		…
856		1263
857	while () {	1264	while () {
858	# results found?	1265	# results found?
859	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} };
860		1267
861	return $cb->(@rr)	1268	(undef $do_search), (undef $do_req), return $cb->(@rr)
862	if @rr;	1269	if @rr;
863		1270
864	# see if there is a cname we can follow	1271	# see if there is a cname we can follow
865	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} };
866		1273
…		…
887	};	1294	};
888		1295
889	$do_search->();	1296	$do_search->();
890	}	1297	}
891		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
892	1;	1332	1;
893		1333
894	=back	1334	=back
895		1335
896	=head1 AUTHOR	1336	=head1 AUTHOR
897		1337
898	Marc Lehmann <schmorp@schmorp.de>	1338	Marc Lehmann <schmorp@schmorp.de>
899	http://home.schmorp.de/	1339	http://home.schmorp.de/
900		1340
901	=cut	1341	=cut
902		1342

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.4 by root, Fri May 23 04:10:40 2008 UTC vs. Revision 1.69 by root, Thu Jul 3 02:03:33 2008 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.4 by root, Fri May 23 04:10:40 2008 UTC vs.
Revision 1.69 by root, Thu Jul 3 02:03:33 2008 UTC