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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.16 by root, Fri May 23 17:47:06 2008 UTC vs.
Revision 1.71 by root, Wed Jul 16 21:17:59 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
14	The stub resolver supports DNS over UDP, optional EDNS0 support for up to	19	The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional
15	4kiB datagrams and automatically falls back to virtual circuit mode for	20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
16	large responses.	21	virtual circuit mode for large responses.
17		22
18	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
19		24
20	=over 4	25	=over 4
21		26
…		…
24	package AnyEvent::DNS;	29	package AnyEvent::DNS;
25		30
26	no warnings;	31	no warnings;
27	use strict;	32	use strict;
28		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
29	use AnyEvent::Socket ();	36	use AnyEvent ();
30	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
31		39
32	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.21;
33		41
34	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
35
36	Tries to resolve the given nodename and service name into sockaddr
37	structures usable to connect to this node and service in a
38	protocol-independent way. It works similarly to the getaddrinfo posix
39	function.
40
41	Example:
42
43	AnyEvent::DNS::addr "google.com", "http", AF_UNSPEC, SOCK_STREAM, sub { ... };
44		43
45	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
46		45
47	Tries to resolve the given domain to IPv4 address(es).	46	Tries to resolve the given domain to IPv4 address(es).
		47
		48	=item AnyEvent::DNS::aaaa $domain, $cb->(@addrs)
		49
		50	Tries to resolve the given domain to IPv6 address(es).
48		51
49	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)	52	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)
50		53
51	Tries to resolve the given domain into a sorted (lower preference value	54	Tries to resolve the given domain into a sorted (lower preference value
52	first) list of domain names.	55	first) list of domain names.
…		…
62	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
63		66
64	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
65	of service records.	68	of service records.
66		69
67	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
68	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
69		72
70	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
71	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
72		75
73	Example:	76	Example:
74		77
75	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
76	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
77		80
78	=item AnyEvent::DNS::ptr $ipv4_or_6, $cb->(@hostnames)	81	=item AnyEvent::DNS::ptr $domain, $cb->(@hostnames)
		82
		83	Tries to make a PTR lookup on the given domain. See C<reverse_lookup>
		84	and C<reverse_verify> if you want to resolve an IP address to a hostname
		85	instead.
		86
		87	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
		88
		89	Tries to resolve the given domain and passes all resource records found to
		90	the callback.
		91
		92	=item AnyEvent::DNS::reverse_lookup $ipv4_or_6, $cb->(@hostnames)
79		93
80	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)	94	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)
81	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
82		97
83	Requires the Socket6 module for IPv6 support.	98	=item AnyEvent::DNS::reverse_verify $ipv4_or_6, $cb->(@hostnames)
		99
		100	The same as C<reverse_lookup>, but does forward-lookups to verify that
		101	the resolved hostnames indeed point to the address, which makes spoofing
		102	harder.
		103
		104	If you want to resolve an address into a hostname, this is the preferred
		105	method: The DNS records could still change, but at least this function
		106	verified that the hostname, at one point in the past, pointed at the IP
		107	address you originally resolved.
84		108
85	Example:	109	Example:
86		110
87	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
88	# => f.root-servers.net	112	# => f.root-servers.net
89		113
90	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
91
92	Tries to resolve the given domain and passes all resource records found to
93	the callback.
94
95	=cut	114	=cut
		115
		116	sub MAX_PKT() { 4096 } # max packet size we advertise and accept
		117
		118	sub DOMAIN_PORT() { 53 } # if this changes drop me a note
96		119
97	sub resolver;	120	sub resolver;
98		121
99	sub a($$) {	122	sub a($$) {
100	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
102	resolver->resolve ($domain => "a", sub {	125	resolver->resolve ($domain => "a", sub {
103	$cb->(map $_->[3], @_);	126	$cb->(map $_->[3], @_);
104	});	127	});
105	}	128	}
106		129
		130	sub aaaa($$) {
		131	my ($domain, $cb) = @_;
		132
		133	resolver->resolve ($domain => "aaaa", sub {
		134	$cb->(map $_->[3], @_);
		135	});
		136	}
		137
107	sub mx($$) {	138	sub mx($$) {
108	my ($domain, $cb) = @_;	139	my ($domain, $cb) = @_;
109		140
110	resolver->resolve ($domain => "mx", sub {	141	resolver->resolve ($domain => "mx", sub {
111	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);	142	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);
…		…
131	sub srv($$$$) {	162	sub srv($$$$) {
132	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
133		164
134	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
135	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
136	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
137	});	194	});
138	}	195	}
139		196
140	sub ptr($$) {	197	sub ptr($$) {
141	my ($ip, $cb) = @_;	198	my ($domain, $cb) = @_;
142		199
143	my $name;
144
145	if (AnyEvent::Util::dotted_quad $ip) {
146	$name = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
147	} else {
148	require Socket6;
149	$name = join ".",
150	(reverse split //,
151	unpack "H*", Socket6::inet_pton (Socket::AF_INET6, $ip)),
152	"ip6.arpa.";
153	}
154
155	resolver->resolve ($name => "ptr", sub {	200	resolver->resolve ($domain => "ptr", sub {
156	$cb->(map $_->[3], @_);	201	$cb->(map $_->[3], @_);
157	});	202	});
158	}	203	}
159		204
160	sub any($$) {	205	sub any($$) {
161	my ($domain, $cb) = @_;	206	my ($domain, $cb) = @_;
162		207
163	resolver->resolve ($domain => "*", $cb);	208	resolver->resolve ($domain => "*", $cb);
164	}	209	}
165		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
		239	my ($ip, $cb) = @_;
		240
		241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
		242	or return $cb->();
		243
		244	resolver->resolve ($ip => "ptr", sub {
		245	$cb->(map $_->[3], @_);
		246	});
		247	}
		248
		249	sub reverse_verify($$) {
		250	my ($ip, $cb) = @_;
		251
		252	my $ipn = AnyEvent::Socket::parse_address ($ip)
		253	or return $cb->();
		254
		255	my $af = AnyEvent::Socket::address_family ($ipn);
		256
		257	my @res;
		258	my $cnt;
		259
		260	my $ptr = _munge_ptr $ipn
		261	or return $cb->();
		262
		263	$ip = AnyEvent::Socket::format_address ($ipn); # normalise into the same form
		264
		265	ptr $ptr, sub {
		266	for my $name (@_) {
		267	++$cnt;
		268
		269	# () around AF_INET to work around bug in 5.8
		270	resolver->resolve ("$name." => ($af == (AF_INET) ? "a" : "aaaa"), sub {
		271	for (@_) {
		272	push @res, $name
		273	if $_->[3] eq $ip;
		274	}
		275	$cb->(@res) unless --$cnt;
		276	});
		277	}
		278
		279	$cb->() unless $cnt;
		280	};
		281	}
		282
		283	#################################################################################
		284
166	=back	285	=back
167		286
168	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
169		288
170	=over 4	289	=over 4
171		290
172	=item $AnyEvent::DNS::EDNS0	291	=item $AnyEvent::DNS::EDNS0
173		292
174	This variable decides whether dns_pack automatically enables EDNS0	293	This variable decides whether dns_pack automatically enables EDNS0
175	support. By default, this is disabled (C<0>), but when set to C<1>,	294	support. By default, this is disabled (C<0>), unless overridden by
176	AnyEvent::DNS will use EDNS0 in all requests.	295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
		296	EDNS0 in all requests.
177		297
178	=cut	298	=cut
179		299
180	our $EDNS0 = 0; # set to 1 to enable (partial) edns0	300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0
181		301
182	our %opcode_id = (	302	our %opcode_id = (
183	query => 0,	303	query => 0,
184	iquery => 1,	304	iquery => 1,
185	status => 2,	305	status => 2,
…		…
231	minfo => 14,	351	minfo => 14,
232	mx => 15,	352	mx => 15,
233	txt => 16,	353	txt => 16,
234	aaaa => 28,	354	aaaa => 28,
235	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
236	opt => 41,	357	opt => 41,
237	spf => 99,	358	spf => 99,
238	tkey => 249,	359	tkey => 249,
239	tsig => 250,	360	tsig => 250,
240	ixfr => 251,	361	ixfr => 251,
…		…
253	"*" => 255,	374	"*" => 255,
254	);	375	);
255		376
256	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
257		378
258	# names MUST have a trailing dot
259	sub _enc_qname($) {	379	sub _enc_name($) {
260	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
261	}	381	}
262		382
263	sub _enc_qd() {	383	sub _enc_qd() {
264	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
265	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
266	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
267	}	387	}
268		388
269	sub _enc_rr() {	389	sub _enc_rr() {
270	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
271	}	391	}
272		392
273	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
274		394
275	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
276	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
277		397
278	Resource records are not yet encodable.	398	Resource records are not yet encodable.
279		399
280	Examples:	400	Examples:
281		401
282	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
283	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
284		404
285	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
286		406
287	{	407	{
288	id => 10000,	408	id => 10000,
289	op => "query",	409	op => "query",
290	rc => "nxdomain",	410	rc => "nxdomain",
291		411
292	# flags	412	# flags
293	qr => 1,	413	qr => 1,
294	aa => 0,	414	aa => 0,
295	tc => 0,	415	tc => 0,
296	rd => 0,	416	rd => 0,
297	ra => 0,	417	ra => 0,
298	ad => 0,	418	ad => 0,
299	cd => 0,	419	cd => 0,
300		420
301	qd => [@rr], # query section	421	qd => [@rr], # query section
302	an => [@rr], # answer section	422	an => [@rr], # answer section
303	ns => [@rr], # authority section	423	ns => [@rr], # authority section
304	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
305	}	425	}
306		426
307	=cut	427	=cut
308		428
309	sub dns_pack($) {	429	sub dns_pack($) {
310	my ($req) = @_;	430	my ($req) = @_;
…		…
323	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
324		444
325	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
326	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
327	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
328	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
329		449
330	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
331	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
332	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
333	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
334		454
335	($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size	455	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
336	}	456	}
337		457
338	our $ofs;	458	our $ofs;
339	our $pkt;	459	our $pkt;
340		460
341	# bitches	461	# bitches
342	sub _dec_qname {	462	sub _dec_name {
343	my @res;	463	my @res;
344	my $redir;	464	my $redir;
345	my $ptr = $ofs;	465	my $ptr = $ofs;
346	my $cnt;	466	my $cnt;
347		467
348	while () {	468	while () {
349	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
350		470
351	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
352		472
353	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
354	$ptr++;	474	$ptr++;
355	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
356	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
357	} elsif ($len) {	477	} elsif ($len) {
358	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
363	}	483	}
364	}	484	}
365	}	485	}
366		486
367	sub _dec_qd {	487	sub _dec_qd {
368	my $qname = _dec_qname;	488	my $qname = _dec_name;
369	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
370	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
371	}	491	}
372		492
373	our %dec_rr = (	493	our %dec_rr = (
374	1 => sub { Socket::inet_ntoa $_ }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
375	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
376	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
377	6 => sub {	497	6 => sub {
378	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
379	my $mname = _dec_qname;	499	my $mname = _dec_name;
380	my $rname = _dec_qname;	500	my $rname = _dec_name;
381	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
382	}, # soa	502	}, # soa
383	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
384	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
385	13 => sub { unpack "C/a C/a", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
386	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
387	16 => sub { unpack "(C/a)*", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
388	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
389	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	},
390	99 => sub { unpack "(C/a)*", $_ }, # spf	516	99 => sub { unpack "(C/a)", $_ }, # spf
391	);	517	);
392		518
393	sub _dec_rr {	519	sub _dec_rr {
394	my $qname = _dec_qname;	520	my $name = _dec_name;
395		521
396	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;
397	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
398		524
399	[	525	[
400	$qname,	526	$name,
401	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
402	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
403	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
404	]	530	]
405	}	531	}
…		…
408		534
409	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
410		536
411	Examples:	537	Examples:
412		538
413	# an unsuccessful reply	539	# an unsuccessful reply
414	{	540	{
415	'qd' => [	541	'qd' => [
416	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
417	],	543	],
418	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
419	'ar' => [],	545	'ar' => [],
420	'ns' => [	546	'ns' => [
421	[	547	[
422	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
423	'soa',	549	'soa',
424	'in',	550	'in',
425	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
426	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
427	2008052201, 10800, 1800, 2592000, 86400	553	2008052201, 10800, 1800, 2592000, 86400
428	]	554	]
429	],	555	],
430	'tc' => '',	556	'tc' => '',
431	'ra' => 1,	557	'ra' => 1,
432	'qr' => 1,	558	'qr' => 1,
433	'id' => 45915,	559	'id' => 45915,
434	'aa' => '',	560	'aa' => '',
435	'an' => [],	561	'an' => [],
436	'rd' => 1,	562	'rd' => 1,
437	'op' => 'query'	563	'op' => 'query'
438	}	564	}
439		565
440	# a successful reply	566	# a successful reply
441		567
442	{	568	{
443	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
444	'rc' => 0,	570	'rc' => 0,
445	'ar' => [	571	'ar' => [
446	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
447	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
448	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
449	],	575	],
450	'ns' => [	576	'ns' => [
451	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
452	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
453	],	579	],
454	'tc' => '',	580	'tc' => '',
455	'ra' => 1,	581	'ra' => 1,
456	'qr' => 1,	582	'qr' => 1,
457	'id' => 64265,	583	'id' => 64265,
458	'aa' => '',	584	'aa' => '',
459	'an' => [	585	'an' => [
460	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
461	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
462	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
463	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
464	],	590	],
465	'rd' => 1,	591	'rd' => 1,
466	'op' => 0	592	'op' => 0
467	}	593	}
468		594
469	=cut	595	=cut
470		596
471	sub dns_unpack($) {	597	sub dns_unpack($) {
472	local $pkt = shift;	598	local $pkt = shift;
…		…
543		669
544	=over 4	670	=over 4
545		671
546	=item server => [...]	672	=item server => [...]
547		673
548	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
549	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).
550		677
551	=item timeout => [...]	678	=item timeout => [...]
552		679
553	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
554	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,
…		…
563	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
564	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
565		692
566	=item max_outstanding => $integer	693	=item max_outstanding => $integer
567		694
568	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
569	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>
570	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,
571	until some other requests have been resolved.	698	then the additional requests will be queued until some other requests have
		699	been resolved.
572		700
573	=item reuse => $seconds	701	=item reuse => $seconds
574		702
575	The number of seconds (default: C<60>) that a query id cannot be re-used	703	The number of seconds (default: C<300>) that a query id cannot be re-used
576	after a request. Since AnyEvent::DNS will only allocate up to 30000 ID's	704	after a timeout. If there was no time-out then query ids can be reused
577	at the same time, the long-term maximum number of requests per second is	705	immediately.
578	C<30000 / $seconds> (and thus C<500> requests/s by default).
579		706
580	=back	707	=back
581		708
582	=cut	709	=cut
583		710
584	sub new {	711	sub new {
585	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
586		713
587	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
588	or Carp::croak "socket: $!";
589
590	AnyEvent::Util::fh_nonblocking $fh, 1;
591
592	my $self = bless {	714	my $self = bless {
593	server => [v127.0.0.1],	715	server => [],
594	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
595	search => [],	717	search => [],
596	ndots => 1,	718	ndots => 1,
597	max_outstanding => 10,	719	max_outstanding => 10,
598	reuse => 60, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
599	%arg,	721	%arg,
600	fh => $fh,
601	reuse_q => [],	722	reuse_q => [],
602	}, $class;	723	}, $class;
603		724
604	# search should default to gethostname's domain	725	# search should default to gethostname's domain
605	# but perl lacks a good posix module	726	# but perl lacks a good posix module
606		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
607	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;
608	$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";
609		760
610	$self->_compile;	761	$self->_compile;
611		762
612	$self	763	$self
613	}	764	}
614		765
615	=item $resolver->parse_resolv_conv ($string)	766	=item $resolver->parse_resolv_conv ($string)
616		767
617	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
618	directives are supported (but not neecssarily implemented).	769	directives are supported (but not necessarily implemented).
619		770
620	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	771	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
621	C<options> (C<timeout>, C<attempts>, C<ndots>).	772	C<options> (C<timeout>, C<attempts>, C<ndots>).
622		773
623	Everything else is silently ignored.	774	Everything else is silently ignored.
…		…
635	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
636	if (/^\s*#/) {	787	if (/^\s*#/) {
637	# comment	788	# comment
638	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
639	my $ip = $1;	790	my $ip = $1;
640	if (AnyEvent::Util::dotted_quad $ip) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
641	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	792	push @{ $self->{server} }, $ipn;
642	} else {	793	} else {
643	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
644	}	795	}
645	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
646	$self->{search} = [$1];	797	$self->{search} = [$1];
…		…
669	$self->_compile;	820	$self->_compile;
670	}	821	}
671		822
672	=item $resolver->os_config	823	=item $resolver->os_config
673		824
674	Tries so load and parse F</etc/resolv.conf> on portable opertaing systems. Tries various	825	Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various
675	egregious hacks on windows to force the dns servers and searchlist out of the config.	826	egregious hacks on windows to force the DNS servers and searchlist out of the system.
676		827
677	=cut	828	=cut
678		829
679	sub os_config {	830	sub os_config {
680	my ($self) = @_;	831	my ($self) = @_;
681		832
682	if ($^O =~ /mswin32\|cygwin/i) {	833	$self->{server} = [];
683	# yeah, it suxx... lets hope DNS is DNS in all locales	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.
684		849
685	if (open my $fh, "ipconfig /all \|") {	850	if (open my $fh, "ipconfig /all \|") {
686	delete $self->{server};	851	# parsing strategy: we go through the output and look for
687	delete $self->{search};	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).
688		855
		856	my $dns;
689	while (<$fh>) {	857	while (<$fh>) {
690	# first DNS.* is suffix list	858	if (s/^\s.\bdns\b.://i) {
691	if (/^\s*DNS/) {	859	$dns = 1;
692	while (/\s+([[:alnum:].\-]+)\s*$/) {	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 {
693	push @{ $self->{search} }, $1;	869	push @{ $self->{search} }, $s;
694	$_ = <$fh>;
695	}	870	}
696	last;
697	}	871	}
698	}	872	}
699		873
700	while (<$fh>) {	874	# always add one fallback server
701	# second DNS.* is server address list	875	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
702	if (/^\s*DNS/) {
703	while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) {
704	my $ip = $1;
705	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip
706	if AnyEvent::Util::dotted_quad $ip;
707	$_ = <$fh>;
708	}
709	last;
710	}
711	}
712		876
713	$self->_compile;	877	$self->_compile;
714	}	878	}
715	} else {	879	} else {
716	# try resolv.conf everywhere	880	# try resolv.conf everywhere
…		…
720	$self->parse_resolv_conf (<$fh>);	884	$self->parse_resolv_conf (<$fh>);
721	}	885	}
722	}	886	}
723	}	887	}
724		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;
		915	}
		916
725	sub _compile {	917	sub _compile {
726	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	}
727		927
728	my @retry;	928	my @retry;
729		929
730	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
731	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
749	$NOW = time;	949	$NOW = time;
750	$id->[1]->($res);	950	$id->[1]->($res);
751	}	951	}
752		952
753	sub _recv {	953	sub _recv {
754	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
755		955
756	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	956	# we ignore errors (often one gets port unreachable, but there is
		957	# no good way to take advantage of that.
		958
757	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
758		960
759	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
760		962
761	$self->_feed ($res);	963	$self->_feed ($pkt);
762	}
763	}	964	}
764		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
765	sub _exec {	983	sub _exec {
766	my ($self, $req, $retry) = @_;	984	my ($self, $req) = @_;
767		985
		986	my $retry; # of retries
		987	my $do_retry;
		988
		989	$do_retry = sub {
768	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
769	my ($server, $timeout) = @$retry_cfg;	997	my ($server, $timeout) = @$retry_cfg;
770		998
771	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
772	$NOW = time;	1000	$NOW = time;
773		1001
774	# timeout, try next	1002	# timeout, try next
775	$self->_exec ($req, $retry + 1);	1003	&$do_retry if $do_retry;
776	}), sub {	1004	}), sub {
777	my ($res) = @_;	1005	my ($res) = @_;
778		1006
779	if ($res->{tc}) {	1007	if ($res->{tc}) {
780	# success, but truncated, so use tcp	1008	# success, but truncated, so use tcp
781	AnyEvent::Socket::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1009	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1010	return unless $do_retry; # some other request could have invalidated us already
		1011
782	my ($fh) = @_	1012	my ($fh) = @_
783	or return $self->_exec ($req, $retry + 1);	1013	or return &$do_retry;
784		1014
785	my $handle = new AnyEvent::Handle	1015	my $handle; $handle = new AnyEvent::Handle
786	fh => $fh,	1016	fh => $fh,
		1017	timeout => $timeout,
787	on_error => sub {	1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
788	# failure, try next	1021	# failure, try next
789	$self->_exec ($req, $retry + 1);	1022	&$do_retry;
790	};	1023	};
791		1024
792	$handle->push_write (pack "n/a", $req->[0]);	1025	$handle->push_write (pack "n/a", $req->[0]);
793	$handle->push_read_chunk (2, sub {	1026	$handle->push_read (chunk => 2, sub {
794	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
795	$self->_feed ($_[1]);	1029	$self->_feed ($_[1]);
796	});	1030	});
797	});	1031	});
798	shutdown $fh, 1;
799		1032
800	}, sub { $timeout };	1033	}, sub { $timeout });
801		1034
802	} else {	1035	} else {
803	# success	1036	# success
804	$self->{id}{$req->[2]} = 1;	1037	$self->_free_id ($req->[2], $retry > 1);
805	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1038	undef $do_retry; return $req->[1]->($res);
806	--$self->{outstanding};
807	$self->_scheduler;
808
809	$req->[1]->($res);
810	}	1039	}
811	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
812		1043
813	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
814	} else {	1045	? $self->{fh4} : $self->{fh6}
815	# failure	1046	or return &$do_retry;
816	$self->{id}{$req->[2]} = 1;
817	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
818	--$self->{outstanding};
819	$self->_scheduler;
820		1047
821	$req->[1]->();	1048	send $fh, $req->[0], 0, $sa;
822	}	1049	};
		1050
		1051	&$do_retry;
823	}	1052	}
824		1053
825	sub _scheduler {	1054	sub _scheduler {
826	my ($self) = @_;	1055	my ($self) = @_;
		1056
		1057	no strict 'refs';
827		1058
828	$NOW = time;	1059	$NOW = time;
829		1060
830	# first clear id reuse queue	1061	# first clear id reuse queue
831	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
840	$self->_scheduler;	1071	$self->_scheduler;
841	});	1072	});
842	last;	1073	last;
843	}	1074	}
844		1075
845	my $req = shift @{ $self->{queue} }	1076	if (my $req = shift @{ $self->{queue} }) {
846	or last;	1077	# found a request in the queue, execute it
847
848	while () {	1078	while () {
849	$req->[2] = int rand 65536;	1079	$req->[2] = int rand 65536;
850	last unless exists $self->{id}{$req->[2]};	1080	last unless exists $self->{id}{$req->[2]};
		1081	}
		1082
		1083	++$self->{outstanding};
		1084	$self->{id}{$req->[2]} = 1;
		1085	substr $req->[0], 0, 2, pack "n", $req->[2];
		1086
		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;
851	}	1096	}
852
853	$self->{id}{$req->[2]} = 1;
854	substr $req->[0], 0, 2, pack "n", $req->[2];
855
856	++$self->{outstanding};
857	$self->_exec ($req, 0);
858	}	1097	}
859	}	1098	}
860		1099
861	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
862		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
863	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
864	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
865	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
866	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
867		1111
868	=cut	1112	=cut
869		1113
870	sub request($$) {	1114	sub request($$) {
871	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
…		…
874	$self->_scheduler;	1118	$self->_scheduler;
875	}	1119	}
876		1120
877	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))
878		1122
879	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>.
880	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.
881		1130
882	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
883	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.
884		1133
885	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.
886		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
887	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
888	supporting recursive queries, will not do any recursive queries itself and	1150	supporting recursive queries, will not do any recursive queries itself and
889	is not secure when used against an untrusted name server.	1151	is not secure when used against an untrusted name server.
890		1152
891	The following options are supported:	1153	The following options are supported:
892		1154
…		…
894		1156
895	=item search => [$suffix...]	1157	=item search => [$suffix...]
896		1158
897	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
898	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
899	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1161	C<ndots> and C<search> values define its value (depending on C<ndots>, the
900	then the searchlist will be ignored.	1162	empty suffix will be prepended or appended to that C<search> value). If
		1163	the C<$qname> ends in a dot, then the searchlist will be ignored.
901		1164
902	=item accept => [$type...]	1165	=item accept => [$type...]
903		1166
904	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
905	accepted and returned. The default includes the C<$qtype> and nothing	1168	accepted and returned. The default includes the C<$qtype> and nothing
906	else.	1169	else. If this list includes C<cname>, then CNAME-chains will not be
		1170	followed (because you asked for the CNAME record).
907		1171
908	=item class => "class"	1172	=item class => "class"
909		1173
910	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
911	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.
912		1176
913	=back	1177	=back
914		1178
915	Examples:	1179	Examples:
916		1180
917	$res->resolve ("ruth.plan9.de", "a", sub {	1181	# full example, you can paste this into perl:
918	warn Dumper [@_];	1182	use Data::Dumper;
919	});	1183	use AnyEvent::DNS;
		1184	AnyEvent::DNS::resolver->resolve (
		1185	"google.com", "*", my $cv = AnyEvent->condvar);
		1186	warn Dumper [$cv->recv];
920		1187
		1188	# shortened result:
921	[	1189	# [
		1190	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1191	# 2008052701, 7200, 1800, 1209600, 300 ],
922	[	1192	# [
923	'ruth.schmorp.de',	1193	# 'google.com', 'txt', 'in',
924	'a',	1194	# 'v=spf1 include:_netblocks.google.com ~all'
925	'in',	1195	# ],
926	'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' ],
927	]	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' ]
928	]	1207	# ]
929		1208
		1209	# resolve any records, but return only a and aaaa records:
930	$res->resolve ("test1.laendle", "*",	1210	$res->resolve ("test1.laendle", "*",
931	accept => ["a", "aaaa"],	1211	accept => ["a", "aaaa"],
932	sub {	1212	sub {
933	warn Dumper [@_];	1213	warn Dumper [@_];
934	}	1214	}
935	);	1215	);
936		1216
937	[	1217	# result:
938	[	1218	# [
939	'test1.laendle',	1219	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
940	'a',	1220	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
941	'in',
942	'10.0.0.255'
943	],
944	[
945	'test1.laendle',
946	'aaaa',
947	'in',
948	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
949	]	1221	# ]
950	]
951		1222
952	=cut	1223	=cut
953		1224
954	sub resolve($%) {	1225	sub resolve($%) {
955	my $cb = pop;	1226	my $cb = pop;
…		…
968	my %atype = $opt{accept}	1239	my %atype = $opt{accept}
969	? map +($_ => 1), @{ $opt{accept} }	1240	? map +($_ => 1), @{ $opt{accept} }
970	: ($qtype => 1);	1241	: ($qtype => 1);
971		1242
972	# advance in searchlist	1243	# advance in searchlist
973	my $do_search; $do_search = sub {	1244	my ($do_search, $do_req);
		1245
		1246	$do_search = sub {
974	@search	1247	@search
975	or return $cb->();	1248	or (undef $do_search), (undef $do_req), return $cb->();
976		1249
977	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1250	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
978	my $depth = 2;	1251	my $depth = 10;
979		1252
980	# advance in cname-chain	1253	# advance in cname-chain
981	my $do_req; $do_req = sub {	1254	$do_req = sub {
982	$self->request ({	1255	$self->request ({
983	rd => 1,	1256	rd => 1,
984	qd => [[$name, $qtype, $class]],	1257	qd => [[$name, $qtype, $class]],
985	}, sub {	1258	}, sub {
986	my ($res) = @_	1259	my ($res) = @_
…		…
990		1263
991	while () {	1264	while () {
992	# results found?	1265	# results found?
993	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} };
994		1267
995	return $cb->(@rr)	1268	(undef $do_search), (undef $do_req), return $cb->(@rr)
996	if @rr;	1269	if @rr;
997		1270
998	# see if there is a cname we can follow	1271	# see if there is a cname we can follow
999	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} };
1000		1273
…		…
1021	};	1294	};
1022		1295
1023	$do_search->();	1296	$do_search->();
1024	}	1297	}
1025		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
1026	1;	1332	1;
1027		1333
1028	=back	1334	=back
1029		1335
1030	=head1 AUTHOR	1336	=head1 AUTHOR
1031		1337
1032	Marc Lehmann <schmorp@schmorp.de>	1338	Marc Lehmann <schmorp@schmorp.de>
1033	http://home.schmorp.de/	1339	http://home.schmorp.de/
1034		1340
1035	=cut	1341	=cut
1036		1342

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.16 by root, Fri May 23 17:47:06 2008 UTC vs. Revision 1.71 by root, Wed Jul 16 21:17:59 2008 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.16 by root, Fri May 23 17:47:06 2008 UTC vs.
Revision 1.71 by root, Wed Jul 16 21:17:59 2008 UTC