[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 1.96 by root, Mon Jun 29 21:00:32 2009 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
		8
		9	my $cv = AnyEvent->condvar;
		10	AnyEvent::DNS::a "www.google.de", $cv;
		11	# ... later
		12	my @addrs = $cv->recv;
8		13
9	=head1 DESCRIPTION	14	=head1 DESCRIPTION
10		15
11	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
12	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
13		18
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 = 4.45;
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
		357	dname => 39, # rfc2672
234	opt => 41,	358	opt => 41,
235	spf => 99,	359	spf => 99,
236	tkey => 249,	360	tkey => 249,
237	tsig => 250,	361	tsig => 250,
238	ixfr => 251,	362	ixfr => 251,
…		…
251	"*" => 255,	375	"*" => 255,
252	);	376	);
253		377
254	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
255		379
256	# names MUST have a trailing dot
257	sub _enc_qname($) {	380	sub _enc_name($) {
258	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
259	}	382	}
260		383
261	sub _enc_qd() {	384	sub _enc_qd() {
262	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
263	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
264	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
265	}	388	}
266		389
267	sub _enc_rr() {	390	sub _enc_rr() {
268	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
269	}	392	}
270		393
271	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
272		395
273	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
274	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
275		398
276	Resource records are not yet encodable.	399	Resource records are not yet encodable.
277		400
278	Examples:	401	Examples:
279		402
280	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
281	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
282		405
283	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
284		407
285	{	408	{
286	id => 10000,	409	id => 10000,
287	op => "query",	410	op => "query",
288	rc => "nxdomain",	411	rc => "nxdomain",
289		412
290	# flags	413	# flags
291	qr => 1,	414	qr => 1,
292	aa => 0,	415	aa => 0,
293	tc => 0,	416	tc => 0,
294	rd => 0,	417	rd => 0,
295	ra => 0,	418	ra => 0,
296	ad => 0,	419	ad => 0,
297	cd => 0,	420	cd => 0,
298		421
299	qd => [@rr], # query section	422	qd => [@rr], # query section
300	an => [@rr], # answer section	423	an => [@rr], # answer section
301	ns => [@rr], # authority section	424	ns => [@rr], # authority section
302	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
303	}	426	}
304		427
305	=cut	428	=cut
306		429
307	sub dns_pack($) {	430	sub dns_pack($) {
308	my ($req) = @_;	431	my ($req) = @_;
…		…
321	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
322		445
323	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
324	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
325	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
326	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
327		450
328	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
329	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
330	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
331	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
332		455
333	($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
334	}	457	}
335		458
336	our $ofs;	459	our $ofs;
337	our $pkt;	460	our $pkt;
338		461
339	# bitches	462	# bitches
340	sub _dec_qname {	463	sub _dec_name {
341	my @res;	464	my @res;
342	my $redir;	465	my $redir;
343	my $ptr = $ofs;	466	my $ptr = $ofs;
344	my $cnt;	467	my $cnt;
345		468
346	while () {	469	while () {
347	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
348		471
349	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
350		473
351	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
352	$ptr++;	475	$ptr++;
353	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
354	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
355	} elsif ($len) {	478	} elsif ($len) {
356	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
361	}	484	}
362	}	485	}
363	}	486	}
364		487
365	sub _dec_qd {	488	sub _dec_qd {
366	my $qname = _dec_qname;	489	my $qname = _dec_name;
367	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
368	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
369	}	492	}
370		493
371	our %dec_rr = (	494	our %dec_rr = (
372	1 => sub { Socket::inet_ntoa $_ }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
373	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
374	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
375	6 => sub {	498	6 => sub {
376	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
377	my $mname = _dec_qname;	500	my $mname = _dec_name;
378	my $rname = _dec_qname;	501	my $rname = _dec_name;
379	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
380	}, # soa	503	}, # soa
381	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
382	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
383	13 => sub { unpack "C/a C/a", $_ }, # hinfo	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
384	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
385	16 => sub { unpack "(C/a)*", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
386	28 => sub { sprintf "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", unpack "n8" }, # aaaa	509	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
387	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
388	99 => sub { unpack "(C/a)*", $_ }, # spf	518	99 => sub { unpack "(C/a)", $_ }, # spf
389	);	519	);
390		520
391	sub _dec_rr {	521	sub _dec_rr {
392	my $qname = _dec_qname;	522	my $name = _dec_name;
393		523
394	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;
395	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
396		526
397	[	527	[
398	$qname,	528	$name,
399	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
400	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
401	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
402	]	532	]
403	}	533	}
…		…
406		536
407	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
408		538
409	Examples:	539	Examples:
410		540
411	# an unsuccessful reply	541	# an unsuccessful reply
412	{	542	{
413	'qd' => [	543	'qd' => [
414	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
415	],	545	],
416	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
417	'ar' => [],	547	'ar' => [],
418	'ns' => [	548	'ns' => [
419	[	549	[
420	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
421	'soa',	551	'soa',
422	'in',	552	'in',
423	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
424	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
425	2008052201, 10800, 1800, 2592000, 86400	555	2008052201, 10800, 1800, 2592000, 86400
426	]	556	]
427	],	557	],
428	'tc' => '',	558	'tc' => '',
429	'ra' => 1,	559	'ra' => 1,
430	'qr' => 1,	560	'qr' => 1,
431	'id' => 45915,	561	'id' => 45915,
432	'aa' => '',	562	'aa' => '',
433	'an' => [],	563	'an' => [],
434	'rd' => 1,	564	'rd' => 1,
435	'op' => 'query'	565	'op' => 'query'
436	}	566	}
437		567
438	# a successful reply	568	# a successful reply
439		569
440	{	570	{
441	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
442	'rc' => 0,	572	'rc' => 0,
443	'ar' => [	573	'ar' => [
444	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
445	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
446	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
447	],	577	],
448	'ns' => [	578	'ns' => [
449	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
450	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
451	],	581	],
452	'tc' => '',	582	'tc' => '',
453	'ra' => 1,	583	'ra' => 1,
454	'qr' => 1,	584	'qr' => 1,
455	'id' => 64265,	585	'id' => 64265,
456	'aa' => '',	586	'aa' => '',
457	'an' => [	587	'an' => [
458	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
459	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
460	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
461	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
462	],	592	],
463	'rd' => 1,	593	'rd' => 1,
464	'op' => 0	594	'op' => 0
465	}	595	}
466		596
467	=cut	597	=cut
468		598
469	sub dns_unpack($) {	599	sub dns_unpack($) {
470	local $pkt = shift;	600	local $pkt = shift;
…		…
525		655
526	our $RESOLVER;	656	our $RESOLVER;
527		657
528	sub resolver() {	658	sub resolver() {
529	$RESOLVER \|\| do {	659	$RESOLVER \|\| do {
530	$RESOLVER = new AnyEvent::DNS;	660	$RESOLVER = new AnyEvent::DNS untaint => 1;
531	$RESOLVER->os_config;	661	$RESOLVER->os_config;
532	$RESOLVER	662	$RESOLVER
533	}	663	}
534	}	664	}
535		665
…		…
541		671
542	=over 4	672	=over 4
543		673
544	=item server => [...]	674	=item server => [...]
545		675
546	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
547	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).
548		679
549	=item timeout => [...]	680	=item timeout => [...]
550		681
551	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
552	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,
…		…
561	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
562	tries to resolve the name without any suffixes first.	693	tries to resolve the name without any suffixes first.
563		694
564	=item max_outstanding => $integer	695	=item max_outstanding => $integer
565		696
566	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
567	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>
568	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,
569	until some other requests have been resolved.	700	then the additional requests will be queued until some other requests have
		701	been resolved.
570		702
571	=item reuse => $seconds	703	=item reuse => $seconds
572		704
573	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
574	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
575	at the same time, the long-term maximum number of requests per second is	707	immediately.
576	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.
577		713
578	=back	714	=back
579		715
580	=cut	716	=cut
581		717
582	sub new {	718	sub new {
583	my ($class, %arg) = @_;	719	my ($class, %arg) = @_;
584		720
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 {	721	my $self = bless {
591	server => [v127.0.0.1],	722	server => [],
592	timeout => [2, 5, 5],	723	timeout => [2, 5, 5],
593	search => [],	724	search => [],
594	ndots => 1,	725	ndots => 1,
595	max_outstanding => 10,	726	max_outstanding => 10,
596	reuse => 60, # reuse id's after 5 minutes only, if possible	727	reuse => 300,
597	%arg,	728	%arg,
598	fh => $fh,
599	reuse_q => [],	729	reuse_q => [],
600	}, $class;	730	}, $class;
601		731
602	# search should default to gethostname's domain	732	# search should default to gethostname's domain
603	# but perl lacks a good posix module	733	# but perl lacks a good posix module
604		734
		735	# try to create an ipv4 and an ipv6 socket
		736	# only fail when we cannot create either
		737	my $got_socket;
		738
605	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;
606	$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";
607		767
608	$self->_compile;	768	$self->_compile;
609		769
610	$self	770	$self
611	}	771	}
612		772
613	=item $resolver->parse_resolv_conv ($string)	773	=item $resolver->parse_resolv_conv ($string)
614		774
615	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
616	directives are supported (but not neecssarily implemented).	776	directives are supported (but not necessarily implemented).
617		777
618	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	778	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
619	C<options> (C<timeout>, C<attempts>, C<ndots>).	779	C<options> (C<timeout>, C<attempts>, C<ndots>).
620		780
621	Everything else is silently ignored.	781	Everything else is silently ignored.
…		…
633	for (split /\n/, $resolvconf) {	793	for (split /\n/, $resolvconf) {
634	if (/^\s*#/) {	794	if (/^\s*#/) {
635	# comment	795	# comment
636	} elsif (/^\snameserver\s+(\S+)\s$/i) {	796	} elsif (/^\snameserver\s+(\S+)\s$/i) {
637	my $ip = $1;	797	my $ip = $1;
638	if (AnyEvent::Util::dotted_quad $ip) {	798	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
639	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	799	push @{ $self->{server} }, $ipn;
640	} else {	800	} else {
641	warn "nameserver $ip invalid and ignored\n";	801	warn "nameserver $ip invalid and ignored\n";
642	}	802	}
643	} elsif (/^\sdomain\s+(\S)\s+$/i) {	803	} elsif (/^\sdomain\s+(\S)\s+$/i) {
644	$self->{search} = [$1];	804	$self->{search} = [$1];
…		…
667	$self->_compile;	827	$self->_compile;
668	}	828	}
669		829
670	=item $resolver->os_config	830	=item $resolver->os_config
671		831
672	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
673	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.
674		835
675	=cut	836	=cut
676		837
677	sub os_config {	838	sub os_config {
678	my ($self) = @_;	839	my ($self) = @_;
679		840
680	if ($^O =~ /mswin32\|cygwin/i) {	841	$self->{server} = [];
681	# 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.
682		857
683	if (open my $fh, "ipconfig /all \|") {	858	if (open my $fh, "ipconfig /all \|") {
684	delete $self->{server};	859	# parsing strategy: we go through the output and look for
685	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).
686		863
		864	my $dns;
687	while (<$fh>) {	865	while (<$fh>) {
688	# first DNS.* is suffix list	866	if (s/^\s.\bdns\b.://i) {
689	if (/^\s*DNS/) {	867	$dns = 1;
690	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 {
691	push @{ $self->{search} }, $1;	877	push @{ $self->{search} }, $s;
692	$_ = <$fh>;
693	}	878	}
694	last;
695	}	879	}
696	}	880	}
697		881
698	while (<$fh>) {	882	# always add one fallback server
699	# second DNS.* is server address list	883	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		884
711	$self->_compile;	885	$self->_compile;
712	}	886	}
713	} else {	887	} else {
714	# try resolv.conf everywhere	888	# try resolv.conf everywhere
…		…
718	$self->parse_resolv_conf (<$fh>);	892	$self->parse_resolv_conf (<$fh>);
719	}	893	}
720	}	894	}
721	}	895	}
722		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
723	sub _compile {	925	sub _compile {
724	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	}
725		935
726	my @retry;	936	my @retry;
727		937
728	for my $timeout (@{ $self->{timeout} }) {	938	for my $timeout (@{ $self->{timeout} }) {
729	for my $server (@{ $self->{server} }) {	939	for my $server (@{ $self->{server} }) {
…		…
735	}	945	}
736		946
737	sub _feed {	947	sub _feed {
738	my ($self, $res) = @_;	948	my ($self, $res) = @_;
739		949
		950	($res) = $res =~ /^(.*)$/s
		951	if AnyEvent::TAINT && $self->{untaint};
		952
740	$res = dns_unpack $res	953	$res = dns_unpack $res
741	or return;	954	or return;
742		955
743	my $id = $self->{id}{$res->{id}};	956	my $id = $self->{id}{$res->{id}};
744		957
…		…
747	$NOW = time;	960	$NOW = time;
748	$id->[1]->($res);	961	$id->[1]->($res);
749	}	962	}
750		963
751	sub _recv {	964	sub _recv {
752	my ($self) = @_;	965	my ($self, $pkt, $peer) = @_;
753		966
754	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
755	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	970	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
756		971
757	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	972	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
758		973
759	$self->_feed ($res);	974	$self->_feed ($pkt);
760	}
761	}	975	}
762		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
763	sub _exec {	994	sub _exec {
764	my ($self, $req, $retry) = @_;	995	my ($self, $req) = @_;
765		996
		997	my $retry; # of retries
		998	my $do_retry;
		999
		1000	$do_retry = sub {
766	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
767	my ($server, $timeout) = @$retry_cfg;	1008	my ($server, $timeout) = @$retry_cfg;
768		1009
769	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1010	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
770	$NOW = time;	1011	$NOW = time;
771		1012
772	# timeout, try next	1013	# timeout, try next
773	$self->_exec ($req, $retry + 1);	1014	&$do_retry if $do_retry;
774	}), sub {	1015	}), sub {
775	my ($res) = @_;	1016	my ($res) = @_;
776		1017
777	if ($res->{tc}) {	1018	if ($res->{tc}) {
778	# success, but truncated, so use tcp	1019	# success, but truncated, so use tcp
779	AnyEvent::Util::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
780	my ($fh) = @_	1023	my ($fh) = @_
781	or return $self->_exec ($req, $retry + 1);	1024	or return &$do_retry;
782		1025
783	my $handle = new AnyEvent::Handle	1026	my $handle; $handle = new AnyEvent::Handle
784	fh => $fh,	1027	fh => $fh,
		1028	timeout => $timeout,
785	on_error => sub {	1029	on_error => sub {
		1030	undef $handle;
		1031	return unless $do_retry; # some other request could have invalidated us already
786	# failure, try next	1032	# failure, try next
787	$self->_exec ($req, $retry + 1);	1033	&$do_retry;
788	};	1034	};
789		1035
790	$handle->push_write (pack "n/a", $req->[0]);	1036	$handle->push_write (pack "n/a", $req->[0]);
791	$handle->push_read_chunk (2, sub {	1037	$handle->push_read (chunk => 2, sub {
792	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1038	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1039	undef $handle;
793	$self->_feed ($_[1]);	1040	$self->_feed ($_[1]);
794	});	1041	});
795	});	1042	});
796	shutdown $fh, 1;
797		1043
798	}, sub { $timeout };	1044	}, sub { $timeout });
799		1045
800	} else {	1046	} else {
801	# success	1047	# success
802	$self->{id}{$req->[2]} = 1;	1048	$self->_free_id ($req->[2], $retry > 1);
803	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1049	undef $do_retry; return $req->[1]->($res);
804	--$self->{outstanding};
805	$self->_scheduler;
806
807	$req->[1]->($res);
808	}	1050	}
809	}];	1051	}];
		1052
		1053	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
810		1054
811	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1055	my $fh = AF_INET == Socket::sockaddr_family ($sa)
812	} else {	1056	? $self->{fh4} : $self->{fh6}
813	# failure	1057	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		1058
819	$req->[1]->();	1059	send $fh, $req->[0], 0, $sa;
820	}	1060	};
		1061
		1062	&$do_retry;
821	}	1063	}
822		1064
823	sub _scheduler {	1065	sub _scheduler {
824	my ($self) = @_;	1066	my ($self) = @_;
		1067
		1068	no strict 'refs';
825		1069
826	$NOW = time;	1070	$NOW = time;
827		1071
828	# first clear id reuse queue	1072	# first clear id reuse queue
829	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1073	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
838	$self->_scheduler;	1082	$self->_scheduler;
839	});	1083	});
840	last;	1084	last;
841	}	1085	}
842		1086
843	my $req = shift @{ $self->{queue} }	1087	if (my $req = shift @{ $self->{queue} }) {
844	or last;	1088	# found a request in the queue, execute it
845
846	while () {	1089	while () {
847	$req->[2] = int rand 65536;	1090	$req->[2] = int rand 65536;
848	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;
849	}	1107	}
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	}	1108	}
857	}	1109	}
858		1110
859	=item $resolver->request ($req, $cb->($res))	1111	=item $resolver->request ($req, $cb->($res))
860		1112
		1113	This is the main low-level workhorse for sending DNS requests.
		1114
861	Sends a single request (a hash-ref formated as specified for	1115	This function sends a single request (a hash-ref formated as specified
862	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
863	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
864	was received, or no arguments on timeout.	1121	received, or no arguments in case none of the servers answered.
865		1122
866	=cut	1123	=cut
867		1124
868	sub request($$) {	1125	sub request($$) {
869	my ($self, $req, $cb) = @_;	1126	my ($self, $req, $cb) = @_;
870		1127
871	push @{ $self->{queue} }, [dns_pack $req, $cb];	1128	push @{ $self->{queue} }, [dns_pack $req, $cb];
872	$self->_scheduler;	1129	$self->_scheduler;
873	}	1130	}
874		1131
875	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1132	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
876		1133
877	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1134	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
878	qtype of "*" is supported and means "any").	1135
		1136	A C<$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<$qtype> of "*" is supported and means
		1140	"any" record type.
879		1141
880	The callback will be invoked with a list of matching result records or	1142	The callback will be invoked with a list of matching result records or
881	none on any error or if the name could not be found.	1143	none on any error or if the name could not be found.
882		1144
883	CNAME chains (although illegal) are followed up to a length of 8.	1145	CNAME chains (although illegal) are followed up to a length of 10.
884		1146
		1147	The callback will be invoked with arraryefs of the form C<[$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
885	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
886	supporting recursive queries, will not do any recursive queries itself and	1159	supporting recursive queries, will not do any recursive queries itself and
887	is not secure when used against an untrusted name server.	1160	is not secure when used against an untrusted name server.
888		1161
889	The following options are supported:	1162	The following options are supported:
890		1163
…		…
892		1165
893	=item search => [$suffix...]	1166	=item search => [$suffix...]
894		1167
895	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
896	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
897	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1170	C<ndots> and C<search> values define its value (depending on C<ndots>, the
898	then the searchlist will be ignored.	1171	empty suffix will be prepended or appended to that C<search> value). If
		1172	the C<$qname> ends in a dot, then the searchlist will be ignored.
899		1173
900	=item accept => [$type...]	1174	=item accept => [$type...]
901		1175
902	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
903	accepted and returned. The default includes the C<$qtype> and nothing	1177	accepted and returned. The default includes the C<$qtype> and nothing
904	else.	1178	else. If this list includes C<cname>, then CNAME-chains will not be
		1179	followed (because you asked for the CNAME record).
905		1180
906	=item class => "class"	1181	=item class => "class"
907		1182
908	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
909	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.
910		1185
911	=back	1186	=back
912		1187
913	Examples:	1188	Examples:
914		1189
915	$res->resolve ("ruth.plan9.de", "a", sub {	1190	# full example, you can paste this into perl:
916	warn Dumper [@_];	1191	use Data::Dumper;
917	});	1192	use AnyEvent::DNS;
		1193	AnyEvent::DNS::resolver->resolve (
		1194	"google.com", "*", my $cv = AnyEvent->condvar);
		1195	warn Dumper [$cv->recv];
918		1196
		1197	# shortened result:
919	[	1198	# [
		1199	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1200	# 2008052701, 7200, 1800, 1209600, 300 ],
920	[	1201	# [
921	'ruth.schmorp.de',	1202	# 'google.com', 'txt', 'in',
922	'a',	1203	# 'v=spf1 include:_netblocks.google.com ~all'
923	'in',	1204	# ],
924	'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' ],
925	]	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' ]
926	]	1216	# ]
927		1217
		1218	# resolve any records, but return only a and aaaa records:
928	$res->resolve ("test1.laendle", "*",	1219	$res->resolve ("test1.laendle", "*",
929	accept => ["a", "aaaa"],	1220	accept => ["a", "aaaa"],
930	sub {	1221	sub {
931	warn Dumper [@_];	1222	warn Dumper [@_];
932	}	1223	}
933	);	1224	);
934		1225
935	[	1226	# result:
936	[	1227	# [
937	'test1.laendle',	1228	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
938	'a',	1229	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
939	'in',
940	'10.0.0.255'
941	],
942	[
943	'test1.laendle',
944	'aaaa',
945	'in',
946	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
947	]	1230	# ]
948	]
949		1231
950	=cut	1232	=cut
951		1233
952	sub resolve($%) {	1234	sub resolve($%) {
953	my $cb = pop;	1235	my $cb = pop;
…		…
966	my %atype = $opt{accept}	1248	my %atype = $opt{accept}
967	? map +($_ => 1), @{ $opt{accept} }	1249	? map +($_ => 1), @{ $opt{accept} }
968	: ($qtype => 1);	1250	: ($qtype => 1);
969		1251
970	# advance in searchlist	1252	# advance in searchlist
971	my $do_search; $do_search = sub {	1253	my ($do_search, $do_req);
		1254
		1255	$do_search = sub {
972	@search	1256	@search
973	or return $cb->();	1257	or (undef $do_search), (undef $do_req), return $cb->();
974		1258
975	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1259	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
976	my $depth = 2;	1260	my $depth = 10;
977		1261
978	# advance in cname-chain	1262	# advance in cname-chain
979	my $do_req; $do_req = sub {	1263	$do_req = sub {
980	$self->request ({	1264	$self->request ({
981	rd => 1,	1265	rd => 1,
982	qd => [[$name, $qtype, $class]],	1266	qd => [[$name, $qtype, $class]],
983	}, sub {	1267	}, sub {
984	my ($res) = @_	1268	my ($res) = @_
…		…
988		1272
989	while () {	1273	while () {
990	# results found?	1274	# results found?
991	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} };
992		1276
993	return $cb->(@rr)	1277	(undef $do_search), (undef $do_req), return $cb->(@rr)
994	if @rr;	1278	if @rr;
995		1279
996	# see if there is a cname we can follow	1280	# see if there is a cname we can follow
997	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} };
998		1282
…		…
1019	};	1303	};
1020		1304
1021	$do_search->();	1305	$do_search->();
1022	}	1306	}
1023		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
1024	1;	1341	1;
1025		1342
1026	=back	1343	=back
1027		1344
1028	=head1 AUTHOR	1345	=head1 AUTHOR
1029		1346
1030	Marc Lehmann <schmorp@schmorp.de>	1347	Marc Lehmann <schmorp@schmorp.de>
1031	http://home.schmorp.de/	1348	http://home.schmorp.de/
1032		1349
1033	=cut	1350	=cut
1034		1351

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.14 by root, Fri May 23 16:00:36 2008 UTC vs. Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.14 by root, Fri May 23 16:00:36 2008 UTC vs.
Revision 1.96 by root, Mon Jun 29 21:00:32 2009 UTC