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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.14 by root, Fri May 23 16:00:36 2008 UTC vs.
Revision 1.78 by root, Thu Oct 30 03:43:14 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::Util ();	36	use AnyEvent ();
30	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
31		39
32	=item AnyEvent::DNS::addr $node, $service, $family, $type, $cb->(@addrs)	40	our $VERSION = 4.31;
33		41
34	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
35
36	Tries to resolve the given nodename and service name into sockaddr
37	structures usable to connect to this node and service in a
38	protocol-independent way. It works similarly to the getaddrinfo posix
39	function.
40
41	Example:
42
43	AnyEvent::DNS::addr "google.com", "http", AF_UNSPEC, SOCK_STREAM, sub { ... };
44		43
45	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
46		45
47	Tries to resolve the given domain to IPv4 address(es).	46	Tries to resolve the given domain to IPv4 address(es).
		47
		48	=item AnyEvent::DNS::aaaa $domain, $cb->(@addrs)
		49
		50	Tries to resolve the given domain to IPv6 address(es).
48		51
49	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)	52	=item AnyEvent::DNS::mx $domain, $cb->(@hostnames)
50		53
51	Tries to resolve the given domain into a sorted (lower preference value	54	Tries to resolve the given domain into a sorted (lower preference value
52	first) list of domain names.	55	first) list of domain names.
…		…
62	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
63		66
64	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
65	of service records.	68	of service records.
66		69
67	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
68	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
69		72
70	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
71	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
72		75
73	Example:	76	Example:
74		77
75	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
76	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
77		80
78	=item AnyEvent::DNS::ptr $ipv4_or_6, $cb->(@hostnames)	81	=item AnyEvent::DNS::ptr $domain, $cb->(@hostnames)
		82
		83	Tries to make a PTR lookup on the given domain. See C<reverse_lookup>
		84	and C<reverse_verify> if you want to resolve an IP address to a hostname
		85	instead.
		86
		87	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
		88
		89	Tries to resolve the given domain and passes all resource records found to
		90	the callback.
		91
		92	=item AnyEvent::DNS::reverse_lookup $ipv4_or_6, $cb->(@hostnames)
79		93
80	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)	94	Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form)
81	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
82		97
83	Requires the Socket6 module for IPv6 support.	98	=item AnyEvent::DNS::reverse_verify $ipv4_or_6, $cb->(@hostnames)
		99
		100	The same as C<reverse_lookup>, but does forward-lookups to verify that
		101	the resolved hostnames indeed point to the address, which makes spoofing
		102	harder.
		103
		104	If you want to resolve an address into a hostname, this is the preferred
		105	method: The DNS records could still change, but at least this function
		106	verified that the hostname, at one point in the past, pointed at the IP
		107	address you originally resolved.
84		108
85	Example:	109	Example:
86		110
87	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
88	# => f.root-servers.net	112	# => f.root-servers.net
89		113
90	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
91
92	Tries to resolve the given domain and passes all resource records found to
93	the callback.
94
95	=cut	114	=cut
		115
		116	sub MAX_PKT() { 4096 } # max packet size we advertise and accept
		117
		118	sub DOMAIN_PORT() { 53 } # if this changes drop me a note
96		119
97	sub resolver;	120	sub resolver;
98		121
99	sub a($$) {	122	sub a($$) {
100	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
102	resolver->resolve ($domain => "a", sub {	125	resolver->resolve ($domain => "a", sub {
103	$cb->(map $_->[3], @_);	126	$cb->(map $_->[3], @_);
104	});	127	});
105	}	128	}
106		129
		130	sub aaaa($$) {
		131	my ($domain, $cb) = @_;
		132
		133	resolver->resolve ($domain => "aaaa", sub {
		134	$cb->(map $_->[3], @_);
		135	});
		136	}
		137
107	sub mx($$) {	138	sub mx($$) {
108	my ($domain, $cb) = @_;	139	my ($domain, $cb) = @_;
109		140
110	resolver->resolve ($domain => "mx", sub {	141	resolver->resolve ($domain => "mx", sub {
111	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);	142	$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_);
…		…
131	sub srv($$$$) {	162	sub srv($$$$) {
132	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
133		164
134	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
135	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
136	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
137	});	194	});
138	}	195	}
139		196
140	sub ptr($$) {	197	sub ptr($$) {
141	my ($ip, $cb) = @_;	198	my ($domain, $cb) = @_;
142		199
143	my $name;
144
145	if (AnyEvent::Util::dotted_quad $ip) {
146	$name = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
147	} else {
148	require Socket6;
149	$name = join ".",
150	(reverse split //,
151	unpack "H*", Socket6::inet_pton (Socket::AF_INET6, $ip)),
152	"ip6.arpa.";
153	}
154
155	resolver->resolve ($name => "ptr", sub {	200	resolver->resolve ($domain => "ptr", sub {
156	$cb->(map $_->[3], @_);	201	$cb->(map $_->[3], @_);
157	});	202	});
158	}	203	}
159		204
160	sub any($$) {	205	sub any($$) {
161	my ($domain, $cb) = @_;	206	my ($domain, $cb) = @_;
162		207
163	resolver->resolve ($domain => "*", $cb);	208	resolver->resolve ($domain => "*", $cb);
164	}	209	}
165		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
		239	my ($ip, $cb) = @_;
		240
		241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
		242	or return $cb->();
		243
		244	resolver->resolve ($ip => "ptr", sub {
		245	$cb->(map $_->[3], @_);
		246	});
		247	}
		248
		249	sub reverse_verify($$) {
		250	my ($ip, $cb) = @_;
		251
		252	my $ipn = AnyEvent::Socket::parse_address ($ip)
		253	or return $cb->();
		254
		255	my $af = AnyEvent::Socket::address_family ($ipn);
		256
		257	my @res;
		258	my $cnt;
		259
		260	my $ptr = _munge_ptr $ipn
		261	or return $cb->();
		262
		263	$ip = AnyEvent::Socket::format_address ($ipn); # normalise into the same form
		264
		265	ptr $ptr, sub {
		266	for my $name (@_) {
		267	++$cnt;
		268
		269	# () around AF_INET to work around bug in 5.8
		270	resolver->resolve ("$name." => ($af == (AF_INET) ? "a" : "aaaa"), sub {
		271	for (@_) {
		272	push @res, $name
		273	if $_->[3] eq $ip;
		274	}
		275	$cb->(@res) unless --$cnt;
		276	});
		277	}
		278
		279	$cb->() unless $cnt;
		280	};
		281	}
		282
		283	#################################################################################
		284
		285	=back
		286
166	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
167		288
168	=over 4	289	=over 4
169		290
170	=item $AnyEvent::DNS::EDNS0	291	=item $AnyEvent::DNS::EDNS0
171		292
172	This variable decides whether dns_pack automatically enables EDNS0	293	This variable decides whether dns_pack automatically enables EDNS0
173	support. By default, this is disabled (C<0>), but when set to C<1>,	294	support. By default, this is disabled (C<0>), unless overridden by
174	AnyEvent::DNS will use EDNS0 in all requests.	295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
		296	EDNS0 in all requests.
175		297
176	=cut	298	=cut
177		299
178	our $EDNS0 = 0; # set to 1 to enable (partial) edns0	300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0
179		301
180	our %opcode_id = (	302	our %opcode_id = (
181	query => 0,	303	query => 0,
182	iquery => 1,	304	iquery => 1,
183	status => 2,	305	status => 2,
…		…
229	minfo => 14,	351	minfo => 14,
230	mx => 15,	352	mx => 15,
231	txt => 16,	353	txt => 16,
232	aaaa => 28,	354	aaaa => 28,
233	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
234	opt => 41,	357	opt => 41,
235	spf => 99,	358	spf => 99,
236	tkey => 249,	359	tkey => 249,
237	tsig => 250,	360	tsig => 250,
238	ixfr => 251,	361	ixfr => 251,
…		…
251	"*" => 255,	374	"*" => 255,
252	);	375	);
253		376
254	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
255		378
256	# names MUST have a trailing dot
257	sub _enc_qname($) {	379	sub _enc_name($) {
258	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
259	}	381	}
260		382
261	sub _enc_qd() {	383	sub _enc_qd() {
262	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
263	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
264	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
265	}	387	}
266		388
267	sub _enc_rr() {	389	sub _enc_rr() {
268	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
269	}	391	}
270		392
271	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
272		394
273	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
274	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
275		397
276	Resource records are not yet encodable.	398	Resource records are not yet encodable.
277		399
278	Examples:	400	Examples:
279		401
280	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
281	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
282		404
283	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
284		406
285	{	407	{
286	id => 10000,	408	id => 10000,
287	op => "query",	409	op => "query",
288	rc => "nxdomain",	410	rc => "nxdomain",
289		411
290	# flags	412	# flags
291	qr => 1,	413	qr => 1,
292	aa => 0,	414	aa => 0,
293	tc => 0,	415	tc => 0,
294	rd => 0,	416	rd => 0,
295	ra => 0,	417	ra => 0,
296	ad => 0,	418	ad => 0,
297	cd => 0,	419	cd => 0,
298		420
299	qd => [@rr], # query section	421	qd => [@rr], # query section
300	an => [@rr], # answer section	422	an => [@rr], # answer section
301	ns => [@rr], # authority section	423	ns => [@rr], # authority section
302	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
303	}	425	}
304		426
305	=cut	427	=cut
306		428
307	sub dns_pack($) {	429	sub dns_pack($) {
308	my ($req) = @_;	430	my ($req) = @_;
…		…
321	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
322		444
323	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
324	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
325	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
326	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
327		449
328	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
329	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
330	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
331	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
332		454
333	($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
334	}	456	}
335		457
336	our $ofs;	458	our $ofs;
337	our $pkt;	459	our $pkt;
338		460
339	# bitches	461	# bitches
340	sub _dec_qname {	462	sub _dec_name {
341	my @res;	463	my @res;
342	my $redir;	464	my $redir;
343	my $ptr = $ofs;	465	my $ptr = $ofs;
344	my $cnt;	466	my $cnt;
345		467
346	while () {	468	while () {
347	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
348		470
349	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
350		472
351	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
352	$ptr++;	474	$ptr++;
353	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
354	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
355	} elsif ($len) {	477	} elsif ($len) {
356	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
361	}	483	}
362	}	484	}
363	}	485	}
364		486
365	sub _dec_qd {	487	sub _dec_qd {
366	my $qname = _dec_qname;	488	my $qname = _dec_name;
367	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
368	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
369	}	491	}
370		492
371	our %dec_rr = (	493	our %dec_rr = (
372	1 => sub { Socket::inet_ntoa $_ }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
373	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
374	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
375	6 => sub {	497	6 => sub {
376	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
377	my $mname = _dec_qname;	499	my $mname = _dec_name;
378	my $rname = _dec_qname;	500	my $rname = _dec_name;
379	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
380	}, # soa	502	}, # soa
381	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
382	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
383	13 => sub { unpack "C/a C/a", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
384	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
385	16 => sub { unpack "(C/a)*", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
386	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
387	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	},
388	99 => sub { unpack "(C/a)*", $_ }, # spf	516	99 => sub { unpack "(C/a)", $_ }, # spf
389	);	517	);
390		518
391	sub _dec_rr {	519	sub _dec_rr {
392	my $qname = _dec_qname;	520	my $name = _dec_name;
393		521
394	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;
395	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
396		524
397	[	525	[
398	$qname,	526	$name,
399	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
400	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
401	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
402	]	530	]
403	}	531	}
…		…
406		534
407	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
408		536
409	Examples:	537	Examples:
410		538
411	# an unsuccessful reply	539	# an unsuccessful reply
412	{	540	{
413	'qd' => [	541	'qd' => [
414	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
415	],	543	],
416	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
417	'ar' => [],	545	'ar' => [],
418	'ns' => [	546	'ns' => [
419	[	547	[
420	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
421	'soa',	549	'soa',
422	'in',	550	'in',
423	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
424	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
425	2008052201, 10800, 1800, 2592000, 86400	553	2008052201, 10800, 1800, 2592000, 86400
426	]	554	]
427	],	555	],
428	'tc' => '',	556	'tc' => '',
429	'ra' => 1,	557	'ra' => 1,
430	'qr' => 1,	558	'qr' => 1,
431	'id' => 45915,	559	'id' => 45915,
432	'aa' => '',	560	'aa' => '',
433	'an' => [],	561	'an' => [],
434	'rd' => 1,	562	'rd' => 1,
435	'op' => 'query'	563	'op' => 'query'
436	}	564	}
437		565
438	# a successful reply	566	# a successful reply
439		567
440	{	568	{
441	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
442	'rc' => 0,	570	'rc' => 0,
443	'ar' => [	571	'ar' => [
444	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
445	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
446	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
447	],	575	],
448	'ns' => [	576	'ns' => [
449	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
450	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
451	],	579	],
452	'tc' => '',	580	'tc' => '',
453	'ra' => 1,	581	'ra' => 1,
454	'qr' => 1,	582	'qr' => 1,
455	'id' => 64265,	583	'id' => 64265,
456	'aa' => '',	584	'aa' => '',
457	'an' => [	585	'an' => [
458	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
459	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
460	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
461	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
462	],	590	],
463	'rd' => 1,	591	'rd' => 1,
464	'op' => 0	592	'op' => 0
465	}	593	}
466		594
467	=cut	595	=cut
468		596
469	sub dns_unpack($) {	597	sub dns_unpack($) {
470	local $pkt = shift;	598	local $pkt = shift;
…		…
541		669
542	=over 4	670	=over 4
543		671
544	=item server => [...]	672	=item server => [...]
545		673
546	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
547	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).
548		677
549	=item timeout => [...]	678	=item timeout => [...]
550		679
551	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
552	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,
…		…
561	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
562	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
563		692
564	=item max_outstanding => $integer	693	=item max_outstanding => $integer
565		694
566	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
567	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>
568	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,
569	until some other requests have been resolved.	698	then the additional requests will be queued until some other requests have
		699	been resolved.
570		700
571	=item reuse => $seconds	701	=item reuse => $seconds
572		702
573	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
574	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
575	at the same time, the long-term maximum number of requests per second is	705	immediately.
576	C<30000 / $seconds> (and thus C<500> requests/s by default).
577		706
578	=back	707	=back
579		708
580	=cut	709	=cut
581		710
582	sub new {	711	sub new {
583	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
584		713
585	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
586	or Carp::croak "socket: $!";
587
588	AnyEvent::Util::fh_nonblocking $fh, 1;
589
590	my $self = bless {	714	my $self = bless {
591	server => [v127.0.0.1],	715	server => [],
592	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
593	search => [],	717	search => [],
594	ndots => 1,	718	ndots => 1,
595	max_outstanding => 10,	719	max_outstanding => 10,
596	reuse => 60, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
597	%arg,	721	%arg,
598	fh => $fh,
599	reuse_q => [],	722	reuse_q => [],
600	}, $class;	723	}, $class;
601		724
602	# search should default to gethostname's domain	725	# search should default to gethostname's domain
603	# but perl lacks a good posix module	726	# but perl lacks a good posix module
604		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
605	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;
606	$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";
607		760
608	$self->_compile;	761	$self->_compile;
609		762
610	$self	763	$self
611	}	764	}
612		765
613	=item $resolver->parse_resolv_conv ($string)	766	=item $resolver->parse_resolv_conv ($string)
614		767
615	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
616	directives are supported (but not neecssarily implemented).	769	directives are supported (but not necessarily implemented).
617		770
618	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	771	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
619	C<options> (C<timeout>, C<attempts>, C<ndots>).	772	C<options> (C<timeout>, C<attempts>, C<ndots>).
620		773
621	Everything else is silently ignored.	774	Everything else is silently ignored.
…		…
633	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
634	if (/^\s*#/) {	787	if (/^\s*#/) {
635	# comment	788	# comment
636	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
637	my $ip = $1;	790	my $ip = $1;
638	if (AnyEvent::Util::dotted_quad $ip) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
639	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	792	push @{ $self->{server} }, $ipn;
640	} else {	793	} else {
641	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
642	}	795	}
643	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
644	$self->{search} = [$1];	797	$self->{search} = [$1];
…		…
667	$self->_compile;	820	$self->_compile;
668	}	821	}
669		822
670	=item $resolver->os_config	823	=item $resolver->os_config
671		824
672	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
673	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.
674		827
675	=cut	828	=cut
676		829
677	sub os_config {	830	sub os_config {
678	my ($self) = @_;	831	my ($self) = @_;
679		832
680	if ($^O =~ /mswin32\|cygwin/i) {	833	$self->{server} = [];
681	# 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.
682		849
683	if (open my $fh, "ipconfig /all \|") {	850	if (open my $fh, "ipconfig /all \|") {
684	delete $self->{server};	851	# parsing strategy: we go through the output and look for
685	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).
686		855
		856	my $dns;
687	while (<$fh>) {	857	while (<$fh>) {
688	# first DNS.* is suffix list	858	if (s/^\s.\bdns\b.://i) {
689	if (/^\s*DNS/) {	859	$dns = 1;
690	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 {
691	push @{ $self->{search} }, $1;	869	push @{ $self->{search} }, $s;
692	$_ = <$fh>;
693	}	870	}
694	last;
695	}	871	}
696	}	872	}
697		873
698	while (<$fh>) {	874	# always add one fallback server
699	# second DNS.* is server address list	875	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
700	if (/^\s*DNS/) {
701	while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) {
702	my $ip = $1;
703	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip
704	if AnyEvent::Util::dotted_quad $ip;
705	$_ = <$fh>;
706	}
707	last;
708	}
709	}
710		876
711	$self->_compile;	877	$self->_compile;
712	}	878	}
713	} else {	879	} else {
714	# try resolv.conf everywhere	880	# try resolv.conf everywhere
…		…
718	$self->parse_resolv_conf (<$fh>);	884	$self->parse_resolv_conf (<$fh>);
719	}	885	}
720	}	886	}
721	}	887	}
722		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
723	sub _compile {	917	sub _compile {
724	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	}
725		927
726	my @retry;	928	my @retry;
727		929
728	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
729	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
747	$NOW = time;	949	$NOW = time;
748	$id->[1]->($res);	950	$id->[1]->($res);
749	}	951	}
750		952
751	sub _recv {	953	sub _recv {
752	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
753		955
754	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
755	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
756		960
757	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
758		962
759	$self->_feed ($res);	963	$self->_feed ($pkt);
760	}
761	}	964	}
762		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
763	sub _exec {	983	sub _exec {
764	my ($self, $req, $retry) = @_;	984	my ($self, $req) = @_;
765		985
		986	my $retry; # of retries
		987	my $do_retry;
		988
		989	$do_retry = sub {
766	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
767	my ($server, $timeout) = @$retry_cfg;	997	my ($server, $timeout) = @$retry_cfg;
768		998
769	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
770	$NOW = time;	1000	$NOW = time;
771		1001
772	# timeout, try next	1002	# timeout, try next
773	$self->_exec ($req, $retry + 1);	1003	&$do_retry if $do_retry;
774	}), sub {	1004	}), sub {
775	my ($res) = @_;	1005	my ($res) = @_;
776		1006
777	if ($res->{tc}) {	1007	if ($res->{tc}) {
778	# success, but truncated, so use tcp	1008	# success, but truncated, so use tcp
779	AnyEvent::Util::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1009	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1010	return unless $do_retry; # some other request could have invalidated us already
		1011
780	my ($fh) = @_	1012	my ($fh) = @_
781	or return $self->_exec ($req, $retry + 1);	1013	or return &$do_retry;
782		1014
783	my $handle = new AnyEvent::Handle	1015	my $handle; $handle = new AnyEvent::Handle
784	fh => $fh,	1016	fh => $fh,
		1017	timeout => $timeout,
785	on_error => sub {	1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
786	# failure, try next	1021	# failure, try next
787	$self->_exec ($req, $retry + 1);	1022	&$do_retry;
788	};	1023	};
789		1024
790	$handle->push_write (pack "n/a", $req->[0]);	1025	$handle->push_write (pack "n/a", $req->[0]);
791	$handle->push_read_chunk (2, sub {	1026	$handle->push_read (chunk => 2, sub {
792	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
793	$self->_feed ($_[1]);	1029	$self->_feed ($_[1]);
794	});	1030	});
795	});	1031	});
796	shutdown $fh, 1;
797		1032
798	}, sub { $timeout };	1033	}, sub { $timeout });
799		1034
800	} else {	1035	} else {
801	# success	1036	# success
802	$self->{id}{$req->[2]} = 1;	1037	$self->_free_id ($req->[2], $retry > 1);
803	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1038	undef $do_retry; return $req->[1]->($res);
804	--$self->{outstanding};
805	$self->_scheduler;
806
807	$req->[1]->($res);
808	}	1039	}
809	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
810		1043
811	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
812	} else {	1045	? $self->{fh4} : $self->{fh6}
813	# failure	1046	or return &$do_retry;
814	$self->{id}{$req->[2]} = 1;
815	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
816	--$self->{outstanding};
817	$self->_scheduler;
818		1047
819	$req->[1]->();	1048	send $fh, $req->[0], 0, $sa;
820	}	1049	};
		1050
		1051	&$do_retry;
821	}	1052	}
822		1053
823	sub _scheduler {	1054	sub _scheduler {
824	my ($self) = @_;	1055	my ($self) = @_;
		1056
		1057	no strict 'refs';
825		1058
826	$NOW = time;	1059	$NOW = time;
827		1060
828	# first clear id reuse queue	1061	# first clear id reuse queue
829	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
838	$self->_scheduler;	1071	$self->_scheduler;
839	});	1072	});
840	last;	1073	last;
841	}	1074	}
842		1075
843	my $req = shift @{ $self->{queue} }	1076	if (my $req = shift @{ $self->{queue} }) {
844	or last;	1077	# found a request in the queue, execute it
845
846	while () {	1078	while () {
847	$req->[2] = int rand 65536;	1079	$req->[2] = int rand 65536;
848	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;
849	}	1096	}
850
851	$self->{id}{$req->[2]} = 1;
852	substr $req->[0], 0, 2, pack "n", $req->[2];
853
854	++$self->{outstanding};
855	$self->_exec ($req, 0);
856	}	1097	}
857	}	1098	}
858		1099
859	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
860		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
861	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
862	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
863	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
864	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
865		1111
866	=cut	1112	=cut
867		1113
868	sub request($$) {	1114	sub request($$) {
869	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
…		…
872	$self->_scheduler;	1118	$self->_scheduler;
873	}	1119	}
874		1120
875	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))
876		1122
877	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>.
878	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.
879		1130
880	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
881	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.
882		1133
883	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.
884		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
885	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
886	supporting recursive queries, will not do any recursive queries itself and	1150	supporting recursive queries, will not do any recursive queries itself and
887	is not secure when used against an untrusted name server.	1151	is not secure when used against an untrusted name server.
888		1152
889	The following options are supported:	1153	The following options are supported:
890		1154
…		…
892		1156
893	=item search => [$suffix...]	1157	=item search => [$suffix...]
894		1158
895	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
896	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
897	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1161	C<ndots> and C<search> values define its value (depending on C<ndots>, the
898	then the searchlist will be ignored.	1162	empty suffix will be prepended or appended to that C<search> value). If
		1163	the C<$qname> ends in a dot, then the searchlist will be ignored.
899		1164
900	=item accept => [$type...]	1165	=item accept => [$type...]
901		1166
902	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
903	accepted and returned. The default includes the C<$qtype> and nothing	1168	accepted and returned. The default includes the C<$qtype> and nothing
904	else.	1169	else. If this list includes C<cname>, then CNAME-chains will not be
		1170	followed (because you asked for the CNAME record).
905		1171
906	=item class => "class"	1172	=item class => "class"
907		1173
908	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
909	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.
910		1176
911	=back	1177	=back
912		1178
913	Examples:	1179	Examples:
914		1180
915	$res->resolve ("ruth.plan9.de", "a", sub {	1181	# full example, you can paste this into perl:
916	warn Dumper [@_];	1182	use Data::Dumper;
917	});	1183	use AnyEvent::DNS;
		1184	AnyEvent::DNS::resolver->resolve (
		1185	"google.com", "*", my $cv = AnyEvent->condvar);
		1186	warn Dumper [$cv->recv];
918		1187
		1188	# shortened result:
919	[	1189	# [
		1190	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1191	# 2008052701, 7200, 1800, 1209600, 300 ],
920	[	1192	# [
921	'ruth.schmorp.de',	1193	# 'google.com', 'txt', 'in',
922	'a',	1194	# 'v=spf1 include:_netblocks.google.com ~all'
923	'in',	1195	# ],
924	'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' ],
925	]	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' ]
926	]	1207	# ]
927		1208
		1209	# resolve any records, but return only a and aaaa records:
928	$res->resolve ("test1.laendle", "*",	1210	$res->resolve ("test1.laendle", "*",
929	accept => ["a", "aaaa"],	1211	accept => ["a", "aaaa"],
930	sub {	1212	sub {
931	warn Dumper [@_];	1213	warn Dumper [@_];
932	}	1214	}
933	);	1215	);
934		1216
935	[	1217	# result:
936	[	1218	# [
937	'test1.laendle',	1219	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
938	'a',	1220	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
939	'in',
940	'10.0.0.255'
941	],
942	[
943	'test1.laendle',
944	'aaaa',
945	'in',
946	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
947	]	1221	# ]
948	]
949		1222
950	=cut	1223	=cut
951		1224
952	sub resolve($%) {	1225	sub resolve($%) {
953	my $cb = pop;	1226	my $cb = pop;
…		…
966	my %atype = $opt{accept}	1239	my %atype = $opt{accept}
967	? map +($_ => 1), @{ $opt{accept} }	1240	? map +($_ => 1), @{ $opt{accept} }
968	: ($qtype => 1);	1241	: ($qtype => 1);
969		1242
970	# advance in searchlist	1243	# advance in searchlist
971	my $do_search; $do_search = sub {	1244	my ($do_search, $do_req);
		1245
		1246	$do_search = sub {
972	@search	1247	@search
973	or return $cb->();	1248	or (undef $do_search), (undef $do_req), return $cb->();
974		1249
975	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1250	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
976	my $depth = 2;	1251	my $depth = 10;
977		1252
978	# advance in cname-chain	1253	# advance in cname-chain
979	my $do_req; $do_req = sub {	1254	$do_req = sub {
980	$self->request ({	1255	$self->request ({
981	rd => 1,	1256	rd => 1,
982	qd => [[$name, $qtype, $class]],	1257	qd => [[$name, $qtype, $class]],
983	}, sub {	1258	}, sub {
984	my ($res) = @_	1259	my ($res) = @_
…		…
988		1263
989	while () {	1264	while () {
990	# results found?	1265	# results found?
991	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} };
992		1267
993	return $cb->(@rr)	1268	(undef $do_search), (undef $do_req), return $cb->(@rr)
994	if @rr;	1269	if @rr;
995		1270
996	# see if there is a cname we can follow	1271	# see if there is a cname we can follow
997	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} };
998		1273
…		…
1019	};	1294	};
1020		1295
1021	$do_search->();	1296	$do_search->();
1022	}	1297	}
1023		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
1024	1;	1332	1;
1025		1333
1026	=back	1334	=back
1027		1335
1028	=head1 AUTHOR	1336	=head1 AUTHOR
1029		1337
1030	Marc Lehmann <schmorp@schmorp.de>	1338	Marc Lehmann <schmorp@schmorp.de>
1031	http://home.schmorp.de/	1339	http://home.schmorp.de/
1032		1340
1033	=cut	1341	=cut
1034		1342

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.14 by root, Fri May 23 16:00:36 2008 UTC vs. Revision 1.78 by root, Thu Oct 30 03:43:14 2008 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.14 by root, Fri May 23 16:00:36 2008 UTC vs.
Revision 1.78 by root, Thu Oct 30 03:43:14 2008 UTC