[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 1.94 by root, Tue Jun 23 23:37:32 2009 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
		8
		9	my $cv = AnyEvent->condvar;
		10	AnyEvent::DNS::a "www.google.de", $cv;
		11	# ... later
		12	my @addrs = $cv->recv;
8		13
9	=head1 DESCRIPTION	14	=head1 DESCRIPTION
10		15
11	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
12	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
13		18
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 = 4.412;
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
		357	dname => 39, # rfc2672
236	opt => 41,	358	opt => 41,
237	spf => 99,	359	spf => 99,
238	tkey => 249,	360	tkey => 249,
239	tsig => 250,	361	tsig => 250,
240	ixfr => 251,	362	ixfr => 251,
…		…
253	"*" => 255,	375	"*" => 255,
254	);	376	);
255		377
256	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
257		379
258	# names MUST have a trailing dot
259	sub _enc_qname($) {	380	sub _enc_name($) {
260	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
261	}	382	}
262		383
263	sub _enc_qd() {	384	sub _enc_qd() {
264	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
265	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
266	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
267	}	388	}
268		389
269	sub _enc_rr() {	390	sub _enc_rr() {
270	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
271	}	392	}
272		393
273	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
274		395
275	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	396	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
276	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
277		398
278	Resource records are not yet encodable.	399	Resource records are not yet encodable.
279		400
280	Examples:	401	Examples:
281		402
282	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
283	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
284		405
285	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
286		407
287	{	408	{
288	id => 10000,	409	id => 10000,
289	op => "query",	410	op => "query",
290	rc => "nxdomain",	411	rc => "nxdomain",
291		412
292	# flags	413	# flags
293	qr => 1,	414	qr => 1,
294	aa => 0,	415	aa => 0,
295	tc => 0,	416	tc => 0,
296	rd => 0,	417	rd => 0,
297	ra => 0,	418	ra => 0,
298	ad => 0,	419	ad => 0,
299	cd => 0,	420	cd => 0,
300		421
301	qd => [@rr], # query section	422	qd => [@rr], # query section
302	an => [@rr], # answer section	423	an => [@rr], # answer section
303	ns => [@rr], # authority section	424	ns => [@rr], # authority section
304	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
305	}	426	}
306		427
307	=cut	428	=cut
308		429
309	sub dns_pack($) {	430	sub dns_pack($) {
310	my ($req) = @_;	431	my ($req) = @_;
…		…
323	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
324		445
325	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
326	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
327	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
328	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
329		450
330	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
331	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
332	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
333	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
334		455
335	($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size	456	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
336	}	457	}
337		458
338	our $ofs;	459	our $ofs;
339	our $pkt;	460	our $pkt;
340		461
341	# bitches	462	# bitches
342	sub _dec_qname {	463	sub _dec_name {
343	my @res;	464	my @res;
344	my $redir;	465	my $redir;
345	my $ptr = $ofs;	466	my $ptr = $ofs;
346	my $cnt;	467	my $cnt;
347		468
348	while () {	469	while () {
349	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
350		471
351	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
352		473
353	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
354	$ptr++;	475	$ptr++;
355	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
356	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
357	} elsif ($len) {	478	} elsif ($len) {
358	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
363	}	484	}
364	}	485	}
365	}	486	}
366		487
367	sub _dec_qd {	488	sub _dec_qd {
368	my $qname = _dec_qname;	489	my $qname = _dec_name;
369	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
370	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
371	}	492	}
372		493
373	our %dec_rr = (	494	our %dec_rr = (
374	1 => sub { Socket::inet_ntoa $_ }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
375	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
376	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
377	6 => sub {	498	6 => sub {
378	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
379	my $mname = _dec_qname;	500	my $mname = _dec_name;
380	my $rname = _dec_qname;	501	my $rname = _dec_name;
381	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
382	}, # soa	503	}, # soa
383	11 => sub { ((Socket::inet_aton substr $_, 0, 4), unpack "C a*", substr $_, 4) }, # wks	504	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
384	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
385	13 => sub { unpack "C/a C/a", $_ }, # hinfo	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
386	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx	507	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
387	16 => sub { unpack "(C/a)*", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
388	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	509	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
389	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv	510	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		511	35 => sub { # naptr
		512	# requires perl 5.10, sorry
		513	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		514	local $ofs = $ofs + $offset - length;
		515	($order, $preference, $flags, $service, $regexp, _dec_name)
		516	},
		517	39 => sub { local $ofs = $ofs - length; _dec_name }, # dname
390	99 => sub { unpack "(C/a)*", $_ }, # spf	518	99 => sub { unpack "(C/a)", $_ }, # spf
391	);	519	);
392		520
393	sub _dec_rr {	521	sub _dec_rr {
394	my $qname = _dec_qname;	522	my $name = _dec_name;
395		523
396	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;	524	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
397	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
398		526
399	[	527	[
400	$qname,	528	$name,
401	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
402	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
403	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
404	]	532	]
405	}	533	}
…		…
408		536
409	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
410		538
411	Examples:	539	Examples:
412		540
413	# an unsuccessful reply	541	# an unsuccessful reply
414	{	542	{
415	'qd' => [	543	'qd' => [
416	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
417	],	545	],
418	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
419	'ar' => [],	547	'ar' => [],
420	'ns' => [	548	'ns' => [
421	[	549	[
422	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
423	'soa',	551	'soa',
424	'in',	552	'in',
425	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
426	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
427	2008052201, 10800, 1800, 2592000, 86400	555	2008052201, 10800, 1800, 2592000, 86400
428	]	556	]
429	],	557	],
430	'tc' => '',	558	'tc' => '',
431	'ra' => 1,	559	'ra' => 1,
432	'qr' => 1,	560	'qr' => 1,
433	'id' => 45915,	561	'id' => 45915,
434	'aa' => '',	562	'aa' => '',
435	'an' => [],	563	'an' => [],
436	'rd' => 1,	564	'rd' => 1,
437	'op' => 'query'	565	'op' => 'query'
438	}	566	}
439		567
440	# a successful reply	568	# a successful reply
441		569
442	{	570	{
443	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
444	'rc' => 0,	572	'rc' => 0,
445	'ar' => [	573	'ar' => [
446	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
447	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
448	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
449	],	577	],
450	'ns' => [	578	'ns' => [
451	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
452	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
453	],	581	],
454	'tc' => '',	582	'tc' => '',
455	'ra' => 1,	583	'ra' => 1,
456	'qr' => 1,	584	'qr' => 1,
457	'id' => 64265,	585	'id' => 64265,
458	'aa' => '',	586	'aa' => '',
459	'an' => [	587	'an' => [
460	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
461	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
462	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
463	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
464	],	592	],
465	'rd' => 1,	593	'rd' => 1,
466	'op' => 0	594	'op' => 0
467	}	595	}
468		596
469	=cut	597	=cut
470		598
471	sub dns_unpack($) {	599	sub dns_unpack($) {
472	local $pkt = shift;	600	local $pkt = shift;
…		…
527		655
528	our $RESOLVER;	656	our $RESOLVER;
529		657
530	sub resolver() {	658	sub resolver() {
531	$RESOLVER \|\| do {	659	$RESOLVER \|\| do {
532	$RESOLVER = new AnyEvent::DNS;	660	$RESOLVER = new AnyEvent::DNS untaint => 1;
533	$RESOLVER->os_config;	661	$RESOLVER->os_config;
534	$RESOLVER	662	$RESOLVER
535	}	663	}
536	}	664	}
537		665
…		…
543		671
544	=over 4	672	=over 4
545		673
546	=item server => [...]	674	=item server => [...]
547		675
548	A list of server addressses (default: C<v127.0.0.1>) in network format (4	676	A list of server addresses (default: C<v127.0.0.1>) in network format
549	octets for IPv4, 16 octets for IPv6 - not yet supported).	677	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		678	IPv6 are supported).
550		679
551	=item timeout => [...]	680	=item timeout => [...]
552		681
553	A list of timeouts to use (also determines the number of retries). To make	682	A list of timeouts to use (also determines the number of retries). To make
554	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	683	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
563	The number of dots (default: C<1>) that a name must have so that the resolver	692	The number of dots (default: C<1>) that a name must have so that the resolver
564	tries to resolve the name without any suffixes first.	693	tries to resolve the name without any suffixes first.
565		694
566	=item max_outstanding => $integer	695	=item max_outstanding => $integer
567		696
568	Most name servers do not handle many parallel requests very well. This option	697	Most name servers do not handle many parallel requests very well. This
569	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	698	option limits the number of outstanding requests to C<$integer>
570	if you request more than this many requests, then the additional requests will be queued	699	(default: C<10>), that means if you request more than this many requests,
571	until some other requests have been resolved.	700	then the additional requests will be queued until some other requests have
		701	been resolved.
572		702
573	=item reuse => $seconds	703	=item reuse => $seconds
574		704
575	The number of seconds (default: C<60>) that a query id cannot be re-used	705	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	706	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	707	immediately.
578	C<30000 / $seconds> (and thus C<500> requests/s by default).	708
		709	=item untaint => $boolean
		710
		711	When true, then the resolver will automatically untaint results, and might
		712	also ignore certain environment variables.
579		713
580	=back	714	=back
581		715
582	=cut	716	=cut
583		717
584	sub new {	718	sub new {
585	my ($class, %arg) = @_;	719	my ($class, %arg) = @_;
586		720
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 {	721	my $self = bless {
593	server => [v127.0.0.1],	722	server => [],
594	timeout => [2, 5, 5],	723	timeout => [2, 5, 5],
595	search => [],	724	search => [],
596	ndots => 1,	725	ndots => 1,
597	max_outstanding => 10,	726	max_outstanding => 10,
598	reuse => 60, # reuse id's after 5 minutes only, if possible	727	reuse => 300,
599	%arg,	728	%arg,
600	fh => $fh,
601	reuse_q => [],	729	reuse_q => [],
602	}, $class;	730	}, $class;
603		731
604	# search should default to gethostname's domain	732	# search should default to gethostname's domain
605	# but perl lacks a good posix module	733	# but perl lacks a good posix module
606		734
		735	# try to create an ipv4 and an ipv6 socket
		736	# only fail when we cannot create either
		737	my $got_socket;
		738
607	Scalar::Util::weaken (my $wself = $self);	739	Scalar::Util::weaken (my $wself = $self);
		740
		741	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		742	++$got_socket;
		743
		744	AnyEvent::Util::fh_nonblocking $fh4, 1;
		745	$self->{fh4} = $fh4;
608	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	746	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		747	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		748	$wself->_recv ($pkt, $peer);
		749	}
		750	});
		751	}
		752
		753	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		754	++$got_socket;
		755
		756	$self->{fh6} = $fh6;
		757	AnyEvent::Util::fh_nonblocking $fh6, 1;
		758	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		759	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		760	$wself->_recv ($pkt, $peer);
		761	}
		762	});
		763	}
		764
		765	$got_socket
		766	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
609		767
610	$self->_compile;	768	$self->_compile;
611		769
612	$self	770	$self
613	}	771	}
614		772
615	=item $resolver->parse_resolv_conv ($string)	773	=item $resolver->parse_resolv_conv ($string)
616		774
617	Parses the given string a sif it were a F<resolv.conf> file. The following	775	Parses the given string as if it were a F<resolv.conf> file. The following
618	directives are supported (but not neecssarily implemented).	776	directives are supported (but not necessarily implemented).
619		777
620	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	778	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
621	C<options> (C<timeout>, C<attempts>, C<ndots>).	779	C<options> (C<timeout>, C<attempts>, C<ndots>).
622		780
623	Everything else is silently ignored.	781	Everything else is silently ignored.
…		…
635	for (split /\n/, $resolvconf) {	793	for (split /\n/, $resolvconf) {
636	if (/^\s*#/) {	794	if (/^\s*#/) {
637	# comment	795	# comment
638	} elsif (/^\snameserver\s+(\S+)\s$/i) {	796	} elsif (/^\snameserver\s+(\S+)\s$/i) {
639	my $ip = $1;	797	my $ip = $1;
640	if (AnyEvent::Util::dotted_quad $ip) {	798	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
641	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	799	push @{ $self->{server} }, $ipn;
642	} else {	800	} else {
643	warn "nameserver $ip invalid and ignored\n";	801	warn "nameserver $ip invalid and ignored\n";
644	}	802	}
645	} elsif (/^\sdomain\s+(\S)\s+$/i) {	803	} elsif (/^\sdomain\s+(\S)\s+$/i) {
646	$self->{search} = [$1];	804	$self->{search} = [$1];
…		…
669	$self->_compile;	827	$self->_compile;
670	}	828	}
671		829
672	=item $resolver->os_config	830	=item $resolver->os_config
673		831
674	Tries so load and parse F</etc/resolv.conf> on portable opertaing systems. Tries various	832	Tries so load and parse F</etc/resolv.conf> on portable operating
675	egregious hacks on windows to force the dns servers and searchlist out of the config.	833	systems. Tries various egregious hacks on windows to force the DNS servers
		834	and searchlist out of the system.
676		835
677	=cut	836	=cut
678		837
679	sub os_config {	838	sub os_config {
680	my ($self) = @_;	839	my ($self) = @_;
681		840
682	if ($^O =~ /mswin32\|cygwin/i) {	841	$self->{server} = [];
683	# yeah, it suxx... lets hope DNS is DNS in all locales	842	$self->{search} = [];
		843
		844	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		845	no strict 'refs';
		846
		847	# there are many options to find the current nameservers etc. on windows
		848	# all of them don't work consistently:
		849	# - the registry thing needs separate code on win32 native vs. cygwin
		850	# - the registry layout differs between windows versions
		851	# - calling windows api functions doesn't work on cygwin
		852	# - ipconfig uses locale-specific messages
		853
		854	# we use ipconfig parsing because, despite all its brokenness,
		855	# it seems most stable in practise.
		856	# for good measure, we append a fallback nameserver to our list.
684		857
685	if (open my $fh, "ipconfig /all \|") {	858	if (open my $fh, "ipconfig /all \|") {
686	delete $self->{server};	859	# parsing strategy: we go through the output and look for
687	delete $self->{search};	860	# :-lines with DNS in them. everything in those is regarded as
		861	# either a nameserver (if it parses as an ip address), or a suffix
		862	# (all else).
688		863
		864	my $dns;
689	while (<$fh>) {	865	while (<$fh>) {
690	# first DNS.* is suffix list	866	if (s/^\s.\bdns\b.://i) {
691	if (/^\s*DNS/) {	867	$dns = 1;
692	while (/\s+([[:alnum:].\-]+)\s*$/) {	868	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		869	$dns = 0;
		870	}
		871	if ($dns && /^\s(\S+)\s$/) {
		872	my $s = $1;
		873	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		874	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		875	push @{ $self->{server} }, $ipn;
		876	} else {
693	push @{ $self->{search} }, $1;	877	push @{ $self->{search} }, $s;
694	$_ = <$fh>;
695	}	878	}
696	last;
697	}	879	}
698	}	880	}
699		881
700	while (<$fh>) {	882	# always add one fallback server
701	# second DNS.* is server address list	883	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		884
713	$self->_compile;	885	$self->_compile;
714	}	886	}
715	} else {	887	} else {
716	# try resolv.conf everywhere	888	# try resolv.conf everywhere
…		…
720	$self->parse_resolv_conf (<$fh>);	892	$self->parse_resolv_conf (<$fh>);
721	}	893	}
722	}	894	}
723	}	895	}
724		896
		897	=item $resolver->timeout ($timeout, ...)
		898
		899	Sets the timeout values. See the C<timeout> constructor argument (and note
		900	that this method uses the values itself, not an array-reference).
		901
		902	=cut
		903
		904	sub timeout {
		905	my ($self, @timeout) = @_;
		906
		907	$self->{timeout} = \@timeout;
		908	$self->_compile;
		909	}
		910
		911	=item $resolver->max_outstanding ($nrequests)
		912
		913	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		914	C<max_outstanding> constructor argument.
		915
		916	=cut
		917
		918	sub max_outstanding {
		919	my ($self, $max) = @_;
		920
		921	$self->{max_outstanding} = $max;
		922	$self->_scheduler;
		923	}
		924
725	sub _compile {	925	sub _compile {
726	my $self = shift;	926	my $self = shift;
		927
		928	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		929	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		930
		931	unless (@{ $self->{server} }) {
		932	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		933	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		934	}
727		935
728	my @retry;	936	my @retry;
729		937
730	for my $timeout (@{ $self->{timeout} }) {	938	for my $timeout (@{ $self->{timeout} }) {
731	for my $server (@{ $self->{server} }) {	939	for my $server (@{ $self->{server} }) {
…		…
737	}	945	}
738		946
739	sub _feed {	947	sub _feed {
740	my ($self, $res) = @_;	948	my ($self, $res) = @_;
741		949
		950	($res) = $res =~ /^(.*)$/s
		951	if AnyEvent::TAINT && $self->{untaint};
		952
742	$res = dns_unpack $res	953	$res = dns_unpack $res
743	or return;	954	or return;
744		955
745	my $id = $self->{id}{$res->{id}};	956	my $id = $self->{id}{$res->{id}};
746		957
…		…
749	$NOW = time;	960	$NOW = time;
750	$id->[1]->($res);	961	$id->[1]->($res);
751	}	962	}
752		963
753	sub _recv {	964	sub _recv {
754	my ($self) = @_;	965	my ($self, $pkt, $peer) = @_;
755		966
756	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	967	# we ignore errors (often one gets port unreachable, but there is
		968	# no good way to take advantage of that.
		969
757	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	970	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
758		971
759	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	972	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
760		973
761	$self->_feed ($res);	974	$self->_feed ($pkt);
762	}
763	}	975	}
764		976
		977	sub _free_id {
		978	my ($self, $id, $timeout) = @_;
		979
		980	if ($timeout) {
		981	# we need to block the id for a while
		982	$self->{id}{$id} = 1;
		983	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		984	} else {
		985	# we can quickly recycle the id
		986	delete $self->{id}{$id};
		987	}
		988
		989	--$self->{outstanding};
		990	$self->_scheduler;
		991	}
		992
		993	# execute a single request, involves sending it with timeouts to multiple servers
765	sub _exec {	994	sub _exec {
766	my ($self, $req, $retry) = @_;	995	my ($self, $req) = @_;
767		996
		997	my $retry; # of retries
		998	my $do_retry;
		999
		1000	$do_retry = sub {
768	if (my $retry_cfg = $self->{retry}[$retry]) {	1001	my $retry_cfg = $self->{retry}[$retry++]
		1002	or do {
		1003	# failure
		1004	$self->_free_id ($req->[2], $retry > 1);
		1005	undef $do_retry; return $req->[1]->();
		1006	};
		1007
769	my ($server, $timeout) = @$retry_cfg;	1008	my ($server, $timeout) = @$retry_cfg;
770		1009
771	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1010	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
772	$NOW = time;	1011	$NOW = time;
773		1012
774	# timeout, try next	1013	# timeout, try next
775	$self->_exec ($req, $retry + 1);	1014	&$do_retry if $do_retry;
776	}), sub {	1015	}), sub {
777	my ($res) = @_;	1016	my ($res) = @_;
778		1017
779	if ($res->{tc}) {	1018	if ($res->{tc}) {
780	# success, but truncated, so use tcp	1019	# success, but truncated, so use tcp
781	AnyEvent::Socket::tcp_connect +(Socket::inet_ntoa $server), 53, sub {	1020	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1021	return unless $do_retry; # some other request could have invalidated us already
		1022
782	my ($fh) = @_	1023	my ($fh) = @_
783	or return $self->_exec ($req, $retry + 1);	1024	or return &$do_retry;
784		1025
785	my $handle = new AnyEvent::Handle	1026	my $handle; $handle = new AnyEvent::Handle
786	fh => $fh,	1027	fh => $fh,
		1028	timeout => $timeout,
787	on_error => sub {	1029	on_error => sub {
		1030	undef $handle;
		1031	return unless $do_retry; # some other request could have invalidated us already
788	# failure, try next	1032	# failure, try next
789	$self->_exec ($req, $retry + 1);	1033	&$do_retry;
790	};	1034	};
791		1035
792	$handle->push_write (pack "n/a", $req->[0]);	1036	$handle->push_write (pack "n/a", $req->[0]);
793	$handle->push_read_chunk (2, sub {	1037	$handle->push_read (chunk => 2, sub {
794	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1038	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1039	undef $handle;
795	$self->_feed ($_[1]);	1040	$self->_feed ($_[1]);
796	});	1041	});
797	});	1042	});
798	shutdown $fh, 1;
799		1043
800	}, sub { $timeout };	1044	}, sub { $timeout });
801		1045
802	} else {	1046	} else {
803	# success	1047	# success
804	$self->{id}{$req->[2]} = 1;	1048	$self->_free_id ($req->[2], $retry > 1);
805	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1049	undef $do_retry; return $req->[1]->($res);
806	--$self->{outstanding};
807	$self->_scheduler;
808
809	$req->[1]->($res);
810	}	1050	}
811	}];	1051	}];
		1052
		1053	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
812		1054
813	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1055	my $fh = AF_INET == Socket::sockaddr_family ($sa)
814	} else {	1056	? $self->{fh4} : $self->{fh6}
815	# failure	1057	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		1058
821	$req->[1]->();	1059	send $fh, $req->[0], 0, $sa;
822	}	1060	};
		1061
		1062	&$do_retry;
823	}	1063	}
824		1064
825	sub _scheduler {	1065	sub _scheduler {
826	my ($self) = @_;	1066	my ($self) = @_;
		1067
		1068	no strict 'refs';
827		1069
828	$NOW = time;	1070	$NOW = time;
829		1071
830	# first clear id reuse queue	1072	# first clear id reuse queue
831	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1073	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
840	$self->_scheduler;	1082	$self->_scheduler;
841	});	1083	});
842	last;	1084	last;
843	}	1085	}
844		1086
845	my $req = shift @{ $self->{queue} }	1087	if (my $req = shift @{ $self->{queue} }) {
846	or last;	1088	# found a request in the queue, execute it
847
848	while () {	1089	while () {
849	$req->[2] = int rand 65536;	1090	$req->[2] = int rand 65536;
850	last unless exists $self->{id}{$req->[2]};	1091	last unless exists $self->{id}{$req->[2]};
		1092	}
		1093
		1094	++$self->{outstanding};
		1095	$self->{id}{$req->[2]} = 1;
		1096	substr $req->[0], 0, 2, pack "n", $req->[2];
		1097
		1098	$self->_exec ($req);
		1099
		1100	} elsif (my $cb = shift @{ $self->{wait} }) {
		1101	# found a wait_for_slot callback, call that one first
		1102	$cb->($self);
		1103
		1104	} else {
		1105	# nothing to do, just exit
		1106	last;
851	}	1107	}
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	}	1108	}
859	}	1109	}
860		1110
861	=item $resolver->request ($req, $cb->($res))	1111	=item $resolver->request ($req, $cb->($res))
862		1112
		1113	This is the main low-level workhorse for sending DNS requests.
		1114
863	Sends a single request (a hash-ref formated as specified for	1115	This function sends a single request (a hash-ref formated as specified
864	C<dns_pack>) to the configured nameservers including	1116	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1117	response. It handles timeouts, retries and automatically falls back to
		1118	virtual circuit mode (TCP) when it receives a truncated reply.
		1119
865	retries. Calls the callback with the decoded response packet if a reply	1120	Calls the callback with the decoded response packet if a reply was
866	was received, or no arguments on timeout.	1121	received, or no arguments in case none of the servers answered.
867		1122
868	=cut	1123	=cut
869		1124
870	sub request($$) {	1125	sub request($$) {
871	my ($self, $req, $cb) = @_;	1126	my ($self, $req, $cb) = @_;
872		1127
873	push @{ $self->{queue} }, [dns_pack $req, $cb];	1128	push @{ $self->{queue} }, [dns_pack $req, $cb];
874	$self->_scheduler;	1129	$self->_scheduler;
875	}	1130	}
876		1131
877	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1132	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
878		1133
879	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1134	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
880	qtype of "*" is supported and means "any").	1135
		1136	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1137	a lowercase name (you have to look at the source to see which aliases are
		1138	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1139	more are known to this module). A C<$qtype> of "*" is supported and means
		1140	"any" record type.
881		1141
882	The callback will be invoked with a list of matching result records or	1142	The callback will be invoked with a list of matching result records or
883	none on any error or if the name could not be found.	1143	none on any error or if the name could not be found.
884		1144
885	CNAME chains (although illegal) are followed up to a length of 8.	1145	CNAME chains (although illegal) are followed up to a length of 10.
886		1146
		1147	The callback will be invoked with arraryefs of the form C<[$name, $type,
		1148	$class, @data>], where C<$name> is the domain name, C<$type> a type string
		1149	or number, C<$class> a class name and @data is resource-record-dependent
		1150	data. For C<a> records, this will be the textual IPv4 addresses, for C<ns>
		1151	or C<cname> records this will be a domain name, for C<txt> records these
		1152	are all the strings and so on.
		1153
		1154	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1155	decoded. All resource records not known to this module will have
		1156	the raw C<rdata> field as fourth entry.
		1157
887	Note that this resolver is just a stub resolver: it requires a nameserver	1158	Note that this resolver is just a stub resolver: it requires a name server
888	supporting recursive queries, will not do any recursive queries itself and	1159	supporting recursive queries, will not do any recursive queries itself and
889	is not secure when used against an untrusted name server.	1160	is not secure when used against an untrusted name server.
890		1161
891	The following options are supported:	1162	The following options are supported:
892		1163
…		…
894		1165
895	=item search => [$suffix...]	1166	=item search => [$suffix...]
896		1167
897	Use the given search list (which might be empty), by appending each one	1168	Use the given search list (which might be empty), by appending each one
898	in turn to the C<$qname>. If this option is missing then the configured	1169	in turn to the C<$qname>. If this option is missing then the configured
899	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1170	C<ndots> and C<search> values define its value (depending on C<ndots>, the
900	then the searchlist will be ignored.	1171	empty suffix will be prepended or appended to that C<search> value). If
		1172	the C<$qname> ends in a dot, then the searchlist will be ignored.
901		1173
902	=item accept => [$type...]	1174	=item accept => [$type...]
903		1175
904	Lists the acceptable result types: only result types in this set will be	1176	Lists the acceptable result types: only result types in this set will be
905	accepted and returned. The default includes the C<$qtype> and nothing	1177	accepted and returned. The default includes the C<$qtype> and nothing
906	else.	1178	else. If this list includes C<cname>, then CNAME-chains will not be
		1179	followed (because you asked for the CNAME record).
907		1180
908	=item class => "class"	1181	=item class => "class"
909		1182
910	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1183	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
911	hesiod are the only ones making sense). The default is "in", of course.	1184	hesiod are the only ones making sense). The default is "in", of course.
912		1185
913	=back	1186	=back
914		1187
915	Examples:	1188	Examples:
916		1189
917	$res->resolve ("ruth.plan9.de", "a", sub {	1190	# full example, you can paste this into perl:
918	warn Dumper [@_];	1191	use Data::Dumper;
919	});	1192	use AnyEvent::DNS;
		1193	AnyEvent::DNS::resolver->resolve (
		1194	"google.com", "*", my $cv = AnyEvent->condvar);
		1195	warn Dumper [$cv->recv];
920		1196
		1197	# shortened result:
921	[	1198	# [
		1199	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1200	# 2008052701, 7200, 1800, 1209600, 300 ],
922	[	1201	# [
923	'ruth.schmorp.de',	1202	# 'google.com', 'txt', 'in',
924	'a',	1203	# 'v=spf1 include:_netblocks.google.com ~all'
925	'in',	1204	# ],
926	'129.13.162.95'	1205	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1206	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1207	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
927	]	1208	# ]
		1209
		1210	# resolve a records:
		1211	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1212
		1213	# result:
		1214	# [
		1215	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
928	]	1216	# ]
929		1217
		1218	# resolve any records, but return only a and aaaa records:
930	$res->resolve ("test1.laendle", "*",	1219	$res->resolve ("test1.laendle", "*",
931	accept => ["a", "aaaa"],	1220	accept => ["a", "aaaa"],
932	sub {	1221	sub {
933	warn Dumper [@_];	1222	warn Dumper [@_];
934	}	1223	}
935	);	1224	);
936		1225
937	[	1226	# result:
938	[	1227	# [
939	'test1.laendle',	1228	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
940	'a',	1229	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
941	'in',
942	'10.0.0.255'
943	],
944	[
945	'test1.laendle',
946	'aaaa',
947	'in',
948	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
949	]	1230	# ]
950	]
951		1231
952	=cut	1232	=cut
953		1233
954	sub resolve($%) {	1234	sub resolve($%) {
955	my $cb = pop;	1235	my $cb = pop;
…		…
968	my %atype = $opt{accept}	1248	my %atype = $opt{accept}
969	? map +($_ => 1), @{ $opt{accept} }	1249	? map +($_ => 1), @{ $opt{accept} }
970	: ($qtype => 1);	1250	: ($qtype => 1);
971		1251
972	# advance in searchlist	1252	# advance in searchlist
973	my $do_search; $do_search = sub {	1253	my ($do_search, $do_req);
		1254
		1255	$do_search = sub {
974	@search	1256	@search
975	or return $cb->();	1257	or (undef $do_search), (undef $do_req), return $cb->();
976		1258
977	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1259	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
978	my $depth = 2;	1260	my $depth = 10;
979		1261
980	# advance in cname-chain	1262	# advance in cname-chain
981	my $do_req; $do_req = sub {	1263	$do_req = sub {
982	$self->request ({	1264	$self->request ({
983	rd => 1,	1265	rd => 1,
984	qd => [[$name, $qtype, $class]],	1266	qd => [[$name, $qtype, $class]],
985	}, sub {	1267	}, sub {
986	my ($res) = @_	1268	my ($res) = @_
…		…
990		1272
991	while () {	1273	while () {
992	# results found?	1274	# results found?
993	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1275	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
994		1276
995	return $cb->(@rr)	1277	(undef $do_search), (undef $do_req), return $cb->(@rr)
996	if @rr;	1278	if @rr;
997		1279
998	# see if there is a cname we can follow	1280	# see if there is a cname we can follow
999	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1281	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
1000		1282
…		…
1021	};	1303	};
1022		1304
1023	$do_search->();	1305	$do_search->();
1024	}	1306	}
1025		1307
		1308	=item $resolver->wait_for_slot ($cb->($resolver))
		1309
		1310	Wait until a free request slot is available and call the callback with the
		1311	resolver object.
		1312
		1313	A request slot is used each time a request is actually sent to the
		1314	nameservers: There are never more than C<max_outstanding> of them.
		1315
		1316	Although you can submit more requests (they will simply be queued until
		1317	a request slot becomes available), sometimes, usually for rate-limiting
		1318	purposes, it is useful to instead wait for a slot before generating the
		1319	request (or simply to know when the request load is low enough so one can
		1320	submit requests again).
		1321
		1322	This is what this method does: The callback will be called when submitting
		1323	a DNS request will not result in that request being queued. The callback
		1324	may or may not generate any requests in response.
		1325
		1326	Note that the callback will only be invoked when the request queue is
		1327	empty, so this does not play well if somebody else keeps the request queue
		1328	full at all times.
		1329
		1330	=cut
		1331
		1332	sub wait_for_slot {
		1333	my ($self, $cb) = @_;
		1334
		1335	push @{ $self->{wait} }, $cb;
		1336	$self->_scheduler;
		1337	}
		1338
		1339	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
		1340
1026	1;	1341	1;
1027		1342
1028	=back	1343	=back
1029		1344
1030	=head1 AUTHOR	1345	=head1 AUTHOR
1031		1346
1032	Marc Lehmann <schmorp@schmorp.de>	1347	Marc Lehmann <schmorp@schmorp.de>
1033	http://home.schmorp.de/	1348	http://home.schmorp.de/
1034		1349
1035	=cut	1350	=cut
1036		1351

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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 1.94 by root, Tue Jun 23 23:37:32 2009 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 1.94 by root, Tue Jun 23 23:37:32 2009 UTC