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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.27 by root, Sat May 24 23:10:18 2008 UTC vs.
Revision 1.88 by root, Mon Apr 20 14:34:18 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		8
9	my $cv = AnyEvent->condvar;	9	my $cv = AnyEvent->condvar;
10	AnyEvent::DNS::a "www.google.de", sub { $cv->send (@_) };	10	AnyEvent::DNS::a "www.google.de", $cv;
11	# ... later	11	# ... later
12	my @addrs = $cv->recv;	12	my @addrs = $cv->recv;
13		13
14	=head1 DESCRIPTION	14	=head1 DESCRIPTION
15		15
16	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
17	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
18		18
19	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
20	4kiB datagrams and automatically falls back to virtual circuit mode for	20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
21	large responses.	21	virtual circuit mode for large responses.
22		22
23	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
24		24
25	=over 4	25	=over 4
26		26
…		…
29	package AnyEvent::DNS;	29	package AnyEvent::DNS;
30		30
31	no warnings;	31	no warnings;
32	use strict;	32	use strict;
33		33
		34	use Socket qw(AF_INET SOCK_DGRAM SOCK_STREAM);
		35
		36	use AnyEvent ();
34	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
35		39
36	=item AnyEvent::DNS::addr $node, $service, $proto, $family, $type, $cb->([$family, $type, $proto, $sockaddr], ...)	40	our $VERSION = 4.352;
37		41
38	Tries to resolve the given nodename and service name into protocol families	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
39	and sockaddr structures usable to connect to this node and service in a
40	protocol-independent way. It works remotely similar to the getaddrinfo
41	posix function.
42
43	C<$node> is either an IPv4 or IPv6 address or a hostname, C<$service> is
44	either a service name (port name from F</etc/services>) or a numerical
45	port number. If both C<$node> and C<$service> are names, then SRV records
46	will be consulted to find the real service, otherwise they will be
47	used as-is. If you know that the service name is not in your services
48	database, then you can specify the service in the format C<name=port>
49	(e.g. C<http=80>).
50
51	C<$proto> must be a protocol name, currently C<tcp>, C<udp> or
52	C<sctp>. The default is C<tcp>.
53
54	C<$family> must be either C<0> (meaning any protocol is OK), C<4> (use
55	only IPv4) or C<6> (use only IPv6). This setting might be influenced by
56	C<$ENV{PERL_ANYEVENT_PROTOCOLS}>.
57
58	C<$type> must be C<SOCK_STREAM>, C<SOCK_DGRAM> or C<SOCK_SEQPACKET> (or
59	C<undef> in which case it gets automatically chosen).
60
61	The callback will receive zero or more array references that contain
62	C<$family, $type, $proto> for use in C<socket> and a binary
63	C<$sockaddr> for use in C<connect> (or C<bind>).
64
65	The application should try these in the order given.
66
67	Example:
68
69	AnyEvent::DNS::addr "google.com", "http", 0, undef, undef, sub { ... };
70		43
71	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
72		45
73	Tries to resolve the given domain to IPv4 address(es).	46	Tries to resolve the given domain to IPv4 address(es).
74		47
…		…
92	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
93		66
94	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
95	of service records.	68	of service records.
96		69
97	Each srv_rr is an array reference with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
98	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
99		72
100	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
101	should use the RFC algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
102		75
103	Example:	76	Example:
104		77
105	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
106	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
107		80
108	=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)
109		93
110	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)
111	into it's hostname(s).	95	into it's hostname(s). Handles V4MAPPED and V4COMPAT IPv6 addresses
		96	transparently.
		97
		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.
112		108
113	Example:	109	Example:
114		110
115	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
116	# => f.root-servers.net	112	# => f.root-servers.net
117		113
118	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
119
120	Tries to resolve the given domain and passes all resource records found to
121	the callback.
122
123	=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
124		119
125	sub resolver;	120	sub resolver;
126		121
127	sub a($$) {	122	sub a($$) {
128	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
167	sub srv($$$$) {	162	sub srv($$$$) {
168	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
169		164
170	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
171	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
172	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
173	});	194	});
174	}	195	}
175		196
176	sub ptr($$) {	197	sub ptr($$) {
		198	my ($domain, $cb) = @_;
		199
		200	resolver->resolve ($domain => "ptr", sub {
		201	$cb->(map $_->[3], @_);
		202	});
		203	}
		204
		205	sub any($$) {
		206	my ($domain, $cb) = @_;
		207
		208	resolver->resolve ($domain => "*", $cb);
		209	}
		210
		211	# convert textual ip address into reverse lookup form
		212	sub _munge_ptr($) {
		213	my $ipn = $_[0]
		214	or return;
		215
		216	my $ptr;
		217
		218	my $af = AnyEvent::Socket::address_family ($ipn);
		219
		220	if ($af == AF_INET6) {
		221	$ipn = substr $ipn, 0, 16; # anticipate future expansion
		222
		223	# handle v4mapped and v4compat
		224	if ($ipn =~ s/^\x00{10}(?:\xff\xff\|\x00\x00)//) {
		225	$af = AF_INET;
		226	} else {
		227	$ptr = join ".", (reverse split //, unpack "H32", $ipn), "ip6.arpa.";
		228	}
		229	}
		230
		231	if ($af == AF_INET) {
		232	$ptr = join ".", (reverse unpack "C4", $ipn), "in-addr.arpa.";
		233	}
		234
		235	$ptr
		236	}
		237
		238	sub reverse_lookup($$) {
177	my ($ip, $cb) = @_;	239	my ($ip, $cb) = @_;
178		240
179	$ip = AnyEvent::Socket::parse_ip ($ip)	241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
180	or return $cb->();	242	or return $cb->();
181
182	if (4 == length $ip) {
183	$ip = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
184	} else {
185	$ip = join ".", (reverse split //, unpack "H*", $ip), "ip6.arpa.";
186	}
187		243
188	resolver->resolve ($ip => "ptr", sub {	244	resolver->resolve ($ip => "ptr", sub {
189	$cb->(map $_->[3], @_);	245	$cb->(map $_->[3], @_);
190	});	246	});
191	}	247	}
192		248
193	sub any($$) {	249	sub reverse_verify($$) {
194	my ($domain, $cb) = @_;	250	my ($ip, $cb) = @_;
195		251
196	resolver->resolve ($domain => "*", $cb);	252	my $ipn = AnyEvent::Socket::parse_address ($ip)
197	}
198
199	#############################################################################
200
201	sub addr($$$$$$) {
202	my ($node, $service, $proto, $family, $type, $cb) = @_;
203
204	unless (&AnyEvent::Socket::AF_INET6) {
205	$family != 6
206	or return $cb->();	253	or return $cb->();
207		254
208	$family \|\|= 4;	255	my $af = AnyEvent::Socket::address_family ($ipn);
209	}
210		256
211	$cb->() if $family == 4 && !$AnyEvent::PROTOCOL{ipv4};
212	$cb->() if $family == 6 && !$AnyEvent::PROTOCOL{ipv6};
213
214	$family \|\|=4 unless $AnyEvent::PROTOCOL{ipv6};
215	$family \|\|=6 unless $AnyEvent::PROTOCOL{ipv4};
216
217	$proto \|\|= "tcp";
218	$type \|\|= $proto eq "udp" ? Socket::SOCK_DGRAM : Socket::SOCK_STREAM;
219
220	my $proton = (getprotobyname $proto)[2]
221	or Carp::croak "$proto: protocol unknown";
222
223	my $port;
224
225	if ($service =~ /^(\S+)=(\d+)$/) {
226	($service, $port) = ($1, $2);
227	} elsif ($service =~ /^\d+$/) {
228	($service, $port) = (undef, $service);
229	} else {
230	$port = (getservbyname $service, $proto)[2]
231	or Carp::croak "$service/$proto: service unknown";
232	}
233
234	my @target = [$node, $port];
235
236	# resolve a records / provide sockaddr structures
237	my $resolve = sub {
238	my @res;	257	my @res;
239	my $cv = AnyEvent->condvar (cb => sub {	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;
240	$cb->(	268
241	map $_->[2],	269	# () around AF_INET to work around bug in 5.8
		270	resolver->resolve ("$name." => ($af == (AF_INET) ? "a" : "aaaa"), sub {
242	sort {	271	for (@_) {
243	$AnyEvent::PROTOCOL{$a->[1]} <=> $AnyEvent::PROTOCOL{$b->[1]}	272	push @res, $name
244	or $a->[0] <=> $b->[0]	273	if $_->[3] eq $ip;
245	}	274	}
246	@res	275	$cb->(@res) unless --$cnt;
247	)	276	});
248	});
249
250	$cv->begin;
251	for my $idx (0 .. $#target) {
252	my ($node, $port) = @{ $target[$idx] };
253
254	if (my $noden = AnyEvent::Socket::parse_ip ($node)) {
255	if (4 == length $noden && $family != 6) {
256	push @res, [$idx, "ipv4", [Socket::AF_INET, $type, $proton,
257	AnyEvent::Socket::pack_sockaddr ($port, $noden)]]
258	}
259
260	if (16 == length $noden && $family != 4) {
261	push @res, [$idx, "ipv6", [&AnyEvent::Socket::AF_INET6, $type, $proton,
262	AnyEvent::Socket::pack_sockaddr ( $port, $noden)]]
263	}
264	} else {
265	# ipv4
266	if ($family != 6) {
267	$cv->begin;
268	a $node, sub {
269	push @res, [$idx, "ipv4", [Socket::AF_INET, $type, $proton,
270	AnyEvent::Socket::pack_sockaddr ($port, AnyEvent::Socket::parse_ipv4 ($_))]]
271	for @_;
272	$cv->end;
273	};
274	}
275
276	# ipv6
277	if ($family != 4) {
278	$cv->begin;
279	aaaa $node, sub {
280	push @res, [$idx, "ipv6", [&AnyEvent::Socket::AF_INET6, $type, $proton,
281	AnyEvent::Socket::pack_sockaddr ($port, AnyEvent::Socket::parse_ipv6 ($_))]]
282	for @_;
283	$cv->end;
284	};
285	}
286	}
287	}	277	}
288	$cv->end;	278
		279	$cb->() unless $cnt;
289	};	280	};
290
291	# try srv records, if applicable
292	if ($node eq "localhost") {
293	@target = (["127.0.0.1", $port], ["::1", $port]);
294	&$resolve;
295	} elsif (defined $service && !AnyEvent::Socket::parse_ip ($node)) {
296	srv $service, $proto, $node, sub {
297	my (@srv) = @_;
298
299	# no srv records, continue traditionally
300	@srv
301	or return &$resolve;
302
303	# only srv record has "." => abort
304	$srv[0][2] ne "." \|\| $#srv
305	or return $cb->();
306
307	# use srv records then
308	@target = map ["$_->[3].", $_->[2]],
309	grep $_->[3] ne ".",
310	@srv;
311
312	&$resolve;
313	};
314	} else {
315	&$resolve;
316	}
317	}	281	}
318		282
319	#############################################################################	283	#################################################################################
320		284
321	=back	285	=back
322		286
323	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
324		288
…		…
326		290
327	=item $AnyEvent::DNS::EDNS0	291	=item $AnyEvent::DNS::EDNS0
328		292
329	This variable decides whether dns_pack automatically enables EDNS0	293	This variable decides whether dns_pack automatically enables EDNS0
330	support. By default, this is disabled (C<0>), unless overridden by	294	support. By default, this is disabled (C<0>), unless overridden by
331	C<$ENV{PERL_ANYEVENT_EDNS0>), but when set to C<1>, AnyEvent::DNS will use	295	C<$ENV{PERL_ANYEVENT_EDNS0}>, but when set to C<1>, AnyEvent::DNS will use
332	EDNS0 in all requests.	296	EDNS0 in all requests.
333		297
334	=cut	298	=cut
335		299
336	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0	300	our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0
…		…
387	minfo => 14,	351	minfo => 14,
388	mx => 15,	352	mx => 15,
389	txt => 16,	353	txt => 16,
390	aaaa => 28,	354	aaaa => 28,
391	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
392	opt => 41,	357	opt => 41,
393	spf => 99,	358	spf => 99,
394	tkey => 249,	359	tkey => 249,
395	tsig => 250,	360	tsig => 250,
396	ixfr => 251,	361	ixfr => 251,
…		…
409	"*" => 255,	374	"*" => 255,
410	);	375	);
411		376
412	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
413		378
414	# names MUST have a trailing dot
415	sub _enc_qname($) {	379	sub _enc_name($) {
416	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
417	}	381	}
418		382
419	sub _enc_qd() {	383	sub _enc_qd() {
420	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
421	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
422	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
423	}	387	}
424		388
425	sub _enc_rr() {	389	sub _enc_rr() {
426	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
427	}	391	}
428		392
429	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
430		394
431	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	395	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
432	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
433		397
434	Resource records are not yet encodable.	398	Resource records are not yet encodable.
435		399
436	Examples:	400	Examples:
437		401
438	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
439	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
440		404
441	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
442		406
443	{	407	{
444	id => 10000,	408	id => 10000,
445	op => "query",	409	op => "query",
446	rc => "nxdomain",	410	rc => "nxdomain",
447		411
448	# flags	412	# flags
449	qr => 1,	413	qr => 1,
450	aa => 0,	414	aa => 0,
451	tc => 0,	415	tc => 0,
452	rd => 0,	416	rd => 0,
453	ra => 0,	417	ra => 0,
454	ad => 0,	418	ad => 0,
455	cd => 0,	419	cd => 0,
456		420
457	qd => [@rr], # query section	421	qd => [@rr], # query section
458	an => [@rr], # answer section	422	an => [@rr], # answer section
459	ns => [@rr], # authority section	423	ns => [@rr], # authority section
460	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
461	}	425	}
462		426
463	=cut	427	=cut
464		428
465	sub dns_pack($) {	429	sub dns_pack($) {
466	my ($req) = @_;	430	my ($req) = @_;
…		…
479	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
480		444
481	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
482	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
483	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
484	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
485		449
486	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
487	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
488	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
489	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
490		454
491	($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size	455	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
492	}	456	}
493		457
494	our $ofs;	458	our $ofs;
495	our $pkt;	459	our $pkt;
496		460
497	# bitches	461	# bitches
498	sub _dec_qname {	462	sub _dec_name {
499	my @res;	463	my @res;
500	my $redir;	464	my $redir;
501	my $ptr = $ofs;	465	my $ptr = $ofs;
502	my $cnt;	466	my $cnt;
503		467
504	while () {	468	while () {
505	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
506		470
507	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
508		472
509	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
510	$ptr++;	474	$ptr++;
511	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
512	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
513	} elsif ($len) {	477	} elsif ($len) {
514	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
519	}	483	}
520	}	484	}
521	}	485	}
522		486
523	sub _dec_qd {	487	sub _dec_qd {
524	my $qname = _dec_qname;	488	my $qname = _dec_name;
525	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
526	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
527	}	491	}
528		492
529	our %dec_rr = (	493	our %dec_rr = (
530	1 => sub { join ".", unpack "C4" }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
531	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
532	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
533	6 => sub {	497	6 => sub {
534	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
535	my $mname = _dec_qname;	499	my $mname = _dec_name;
536	my $rname = _dec_qname;	500	my $rname = _dec_name;
537	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
538	}, # soa	502	}, # soa
539	11 => sub { ((join ".", unpack "C4"), unpack "C a*", substr $_, 4) }, # wks	503	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
540	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
541	13 => sub { unpack "C/a C/a", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
542	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx	506	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
543	16 => sub { unpack "(C/a)*", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
544	28 => sub { AnyEvent::Socket::format_ip ($_) }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
545	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv	509	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		510	35 => sub { # naptr
		511	# requires perl 5.10, sorry
		512	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		513	local $ofs = $ofs + $offset - length;
		514	($order, $preference, $flags, $service, $regexp, _dec_name)
		515	},
546	99 => sub { unpack "(C/a)*", $_ }, # spf	516	99 => sub { unpack "(C/a)", $_ }, # spf
547	);	517	);
548		518
549	sub _dec_rr {	519	sub _dec_rr {
550	my $qname = _dec_qname;	520	my $name = _dec_name;
551		521
552	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;	522	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
553	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
554		524
555	[	525	[
556	$qname,	526	$name,
557	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
558	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
559	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
560	]	530	]
561	}	531	}
…		…
564		534
565	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
566		536
567	Examples:	537	Examples:
568		538
569	# an unsuccessful reply	539	# an unsuccessful reply
570	{	540	{
571	'qd' => [	541	'qd' => [
572	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
573	],	543	],
574	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
575	'ar' => [],	545	'ar' => [],
576	'ns' => [	546	'ns' => [
577	[	547	[
578	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
579	'soa',	549	'soa',
580	'in',	550	'in',
581	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
582	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
583	2008052201, 10800, 1800, 2592000, 86400	553	2008052201, 10800, 1800, 2592000, 86400
584	]	554	]
585	],	555	],
586	'tc' => '',	556	'tc' => '',
587	'ra' => 1,	557	'ra' => 1,
588	'qr' => 1,	558	'qr' => 1,
589	'id' => 45915,	559	'id' => 45915,
590	'aa' => '',	560	'aa' => '',
591	'an' => [],	561	'an' => [],
592	'rd' => 1,	562	'rd' => 1,
593	'op' => 'query'	563	'op' => 'query'
594	}	564	}
595		565
596	# a successful reply	566	# a successful reply
597		567
598	{	568	{
599	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
600	'rc' => 0,	570	'rc' => 0,
601	'ar' => [	571	'ar' => [
602	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
603	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
604	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
605	],	575	],
606	'ns' => [	576	'ns' => [
607	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
608	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
609	],	579	],
610	'tc' => '',	580	'tc' => '',
611	'ra' => 1,	581	'ra' => 1,
612	'qr' => 1,	582	'qr' => 1,
613	'id' => 64265,	583	'id' => 64265,
614	'aa' => '',	584	'aa' => '',
615	'an' => [	585	'an' => [
616	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
617	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
618	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
619	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
620	],	590	],
621	'rd' => 1,	591	'rd' => 1,
622	'op' => 0	592	'op' => 0
623	}	593	}
624		594
625	=cut	595	=cut
626		596
627	sub dns_unpack($) {	597	sub dns_unpack($) {
628	local $pkt = shift;	598	local $pkt = shift;
…		…
699		669
700	=over 4	670	=over 4
701		671
702	=item server => [...]	672	=item server => [...]
703		673
704	A list of server addresses (default: C<v127.0.0.1>) in network format (4	674	A list of server addresses (default: C<v127.0.0.1>) in network format
705	octets for IPv4, 16 octets for IPv6 - not yet supported).	675	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		676	IPv6 are supported).
706		677
707	=item timeout => [...]	678	=item timeout => [...]
708		679
709	A list of timeouts to use (also determines the number of retries). To make	680	A list of timeouts to use (also determines the number of retries). To make
710	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	681	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
719	The number of dots (default: C<1>) that a name must have so that the resolver	690	The number of dots (default: C<1>) that a name must have so that the resolver
720	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
721		692
722	=item max_outstanding => $integer	693	=item max_outstanding => $integer
723		694
724	Most name servers do not handle many parallel requests very well. This option	695	Most name servers do not handle many parallel requests very well. This
725	limits the number of outstanding requests to C<$n> (default: C<10>), that means	696	option limits the number of outstanding requests to C<$integer>
726	if you request more than this many requests, then the additional requests will be queued	697	(default: C<10>), that means if you request more than this many requests,
727	until some other requests have been resolved.	698	then the additional requests will be queued until some other requests have
		699	been resolved.
728		700
729	=item reuse => $seconds	701	=item reuse => $seconds
730		702
731	The number of seconds (default: C<300>) that a query id cannot be re-used	703	The number of seconds (default: C<300>) that a query id cannot be re-used
732	after a timeout. If there as no time-out then query id's can be reused	704	after a timeout. If there was no time-out then query ids can be reused
733	immediately.	705	immediately.
734		706
735	=back	707	=back
736		708
737	=cut	709	=cut
738		710
739	sub new {	711	sub new {
740	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
741		713
742	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
743	or Carp::croak "socket: $!";
744
745	AnyEvent::Util::fh_nonblocking $fh, 1;
746
747	my $self = bless {	714	my $self = bless {
748	server => [v127.0.0.1],	715	server => [],
749	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
750	search => [],	717	search => [],
751	ndots => 1,	718	ndots => 1,
752	max_outstanding => 10,	719	max_outstanding => 10,
753	reuse => 300, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
754	%arg,	721	%arg,
755	fh => $fh,
756	reuse_q => [],	722	reuse_q => [],
757	}, $class;	723	}, $class;
758		724
759	# search should default to gethostname's domain	725	# search should default to gethostname's domain
760	# but perl lacks a good posix module	726	# but perl lacks a good posix module
761		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
762	Scalar::Util::weaken (my $wself = $self);	732	Scalar::Util::weaken (my $wself = $self);
		733
		734	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		735	++$got_socket;
		736
		737	AnyEvent::Util::fh_nonblocking $fh4, 1;
		738	$self->{fh4} = $fh4;
763	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	739	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		740	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		741	$wself->_recv ($pkt, $peer);
		742	}
		743	});
		744	}
		745
		746	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		747	++$got_socket;
		748
		749	$self->{fh6} = $fh6;
		750	AnyEvent::Util::fh_nonblocking $fh6, 1;
		751	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		752	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		753	$wself->_recv ($pkt, $peer);
		754	}
		755	});
		756	}
		757
		758	$got_socket
		759	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
764		760
765	$self->_compile;	761	$self->_compile;
766		762
767	$self	763	$self
768	}	764	}
…		…
790	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
791	if (/^\s*#/) {	787	if (/^\s*#/) {
792	# comment	788	# comment
793	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
794	my $ip = $1;	790	my $ip = $1;
795	if (my $ipn = AnyEvent::Socket::parse_ip ($ip)) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
796	push @{ $self->{server} }, $ipn;	792	push @{ $self->{server} }, $ipn;
797	} else {	793	} else {
798	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
799	}	795	}
800	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
…		…
832	=cut	828	=cut
833		829
834	sub os_config {	830	sub os_config {
835	my ($self) = @_;	831	my ($self) = @_;
836		832
837	if ($^O =~ /mswin32\|cygwin/i) {	833	$self->{server} = [];
838	# yeah, it suxx... lets hope DNS is DNS in all locales	834	$self->{search} = [];
		835
		836	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		837	no strict 'refs';
		838
		839	# there are many options to find the current nameservers etc. on windows
		840	# all of them don't work consistently:
		841	# - the registry thing needs separate code on win32 native vs. cygwin
		842	# - the registry layout differs between windows versions
		843	# - calling windows api functions doesn't work on cygwin
		844	# - ipconfig uses locale-specific messages
		845
		846	# we use ipconfig parsing because, despite all its brokenness,
		847	# it seems most stable in practise.
		848	# for good measure, we append a fallback nameserver to our list.
839		849
840	if (open my $fh, "ipconfig /all \|") {	850	if (open my $fh, "ipconfig /all \|") {
841	delete $self->{server};	851	# parsing strategy: we go through the output and look for
842	delete $self->{search};	852	# :-lines with DNS in them. everything in those is regarded as
		853	# either a nameserver (if it parses as an ip address), or a suffix
		854	# (all else).
843		855
		856	my $dns;
844	while (<$fh>) {	857	while (<$fh>) {
845	# first DNS.* is suffix list	858	if (s/^\s.\bdns\b.://i) {
846	if (/^\s*DNS/) {	859	$dns = 1;
847	while (/\s+([[:alnum:].\-]+)\s*$/) {	860	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		861	$dns = 0;
		862	}
		863	if ($dns && /^\s(\S+)\s$/) {
		864	my $s = $1;
		865	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		866	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		867	push @{ $self->{server} }, $ipn;
		868	} else {
848	push @{ $self->{search} }, $1;	869	push @{ $self->{search} }, $s;
849	$_ = <$fh>;
850	}	870	}
851	last;
852	}	871	}
853	}	872	}
854		873
855	while (<$fh>) {	874	# always add one fallback server
856	# second DNS.* is server address list	875	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
857	if (/^\s*DNS/) {
858	while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) {
859	my $ipn = AnyEvent::Socket::parse_ip ("$1"); # "" is necessary here, apparently
860	push @{ $self->{server} }, $ipn
861	if $ipn;
862	$_ = <$fh>;
863	}
864	last;
865	}
866	}
867		876
868	$self->_compile;	877	$self->_compile;
869	}	878	}
870	} else {	879	} else {
871	# try resolv.conf everywhere	880	# try resolv.conf everywhere
…		…
875	$self->parse_resolv_conf (<$fh>);	884	$self->parse_resolv_conf (<$fh>);
876	}	885	}
877	}	886	}
878	}	887	}
879		888
		889	=item $resolver->timeout ($timeout, ...)
		890
		891	Sets the timeout values. See the C<timeout> constructor argument (and note
		892	that this method uses the values itself, not an array-reference).
		893
		894	=cut
		895
		896	sub timeout {
		897	my ($self, @timeout) = @_;
		898
		899	$self->{timeout} = \@timeout;
		900	$self->_compile;
		901	}
		902
		903	=item $resolver->max_outstanding ($nrequests)
		904
		905	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		906	C<max_outstanding> constructor argument.
		907
		908	=cut
		909
		910	sub max_outstanding {
		911	my ($self, $max) = @_;
		912
		913	$self->{max_outstanding} = $max;
		914	$self->_scheduler;
		915	}
		916
880	sub _compile {	917	sub _compile {
881	my $self = shift;	918	my $self = shift;
		919
		920	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		921	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		922
		923	unless (@{ $self->{server} }) {
		924	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		925	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		926	}
882		927
883	my @retry;	928	my @retry;
884		929
885	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
886	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
904	$NOW = time;	949	$NOW = time;
905	$id->[1]->($res);	950	$id->[1]->($res);
906	}	951	}
907		952
908	sub _recv {	953	sub _recv {
909	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
910		955
911	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	956	# we ignore errors (often one gets port unreachable, but there is
		957	# no good way to take advantage of that.
		958
912	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
913		960
914	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
915		962
916	$self->_feed ($res);	963	$self->_feed ($pkt);
917	}
918	}	964	}
919		965
920	sub _free_id {	966	sub _free_id {
921	my ($self, $id, $timeout) = @_;	967	my ($self, $id, $timeout) = @_;
922		968
…		…
952		998
953	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
954	$NOW = time;	1000	$NOW = time;
955		1001
956	# timeout, try next	1002	# timeout, try next
957	&$do_retry;	1003	&$do_retry if $do_retry;
958	}), sub {	1004	}), sub {
959	my ($res) = @_;	1005	my ($res) = @_;
960		1006
961	if ($res->{tc}) {	1007	if ($res->{tc}) {
962	# success, but truncated, so use tcp	1008	# success, but truncated, so use tcp
963	AnyEvent::Socket::tcp_connect ((Socket::inet_ntoa $server), 53, sub {	1009	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1010	return unless $do_retry; # some other request could have invalidated us already
		1011
964	my ($fh) = @_	1012	my ($fh) = @_
965	or return &$do_retry;	1013	or return &$do_retry;
966		1014
967	my $handle = new AnyEvent::Handle	1015	my $handle; $handle = new AnyEvent::Handle
968	fh => $fh,	1016	fh => $fh,
		1017	timeout => $timeout,
969	on_error => sub {	1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
970	# failure, try next	1021	# failure, try next
971	&$do_retry;	1022	&$do_retry;
972	};	1023	};
973		1024
974	$handle->push_write (pack "n/a", $req->[0]);	1025	$handle->push_write (pack "n/a", $req->[0]);
975	$handle->push_read (chunk => 2, sub {	1026	$handle->push_read (chunk => 2, sub {
976	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {	1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
977	$self->_feed ($_[1]);	1029	$self->_feed ($_[1]);
978	});	1030	});
979	});	1031	});
980	shutdown $fh, 1;
981		1032
982	}, sub { $timeout });	1033	}, sub { $timeout });
983		1034
984	} else {	1035	} else {
985	# success	1036	# success
986	$self->_free_id ($req->[2], $retry > 1);	1037	$self->_free_id ($req->[2], $retry > 1);
987	undef $do_retry; return $req->[1]->($res);	1038	undef $do_retry; return $req->[1]->($res);
988	}	1039	}
989	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
990		1043
991	send $self->{fh}, $req->[0], 0, AnyEvent::Socket::pack_sockaddr (53, $server);	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
		1045	? $self->{fh4} : $self->{fh6}
		1046	or return &$do_retry;
		1047
		1048	send $fh, $req->[0], 0, $sa;
992	};	1049	};
993		1050
994	&$do_retry;	1051	&$do_retry;
995	}	1052	}
996		1053
997	sub _scheduler {	1054	sub _scheduler {
998	my ($self) = @_;	1055	my ($self) = @_;
		1056
		1057	no strict 'refs';
999		1058
1000	$NOW = time;	1059	$NOW = time;
1001		1060
1002	# first clear id reuse queue	1061	# first clear id reuse queue
1003	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
1012	$self->_scheduler;	1071	$self->_scheduler;
1013	});	1072	});
1014	last;	1073	last;
1015	}	1074	}
1016		1075
1017	my $req = shift @{ $self->{queue} }	1076	if (my $req = shift @{ $self->{queue} }) {
1018	or last;	1077	# found a request in the queue, execute it
1019
1020	while () {	1078	while () {
1021	$req->[2] = int rand 65536;	1079	$req->[2] = int rand 65536;
1022	last unless exists $self->{id}{$req->[2]};	1080	last unless exists $self->{id}{$req->[2]};
		1081	}
		1082
		1083	++$self->{outstanding};
		1084	$self->{id}{$req->[2]} = 1;
		1085	substr $req->[0], 0, 2, pack "n", $req->[2];
		1086
		1087	$self->_exec ($req);
		1088
		1089	} elsif (my $cb = shift @{ $self->{wait} }) {
		1090	# found a wait_for_slot callback, call that one first
		1091	$cb->($self);
		1092
		1093	} else {
		1094	# nothing to do, just exit
		1095	last;
1023	}	1096	}
1024
1025	++$self->{outstanding};
1026	$self->{id}{$req->[2]} = 1;
1027	substr $req->[0], 0, 2, pack "n", $req->[2];
1028
1029	$self->_exec ($req);
1030	}	1097	}
1031	}	1098	}
1032		1099
1033	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
1034		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
1035	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
1036	C<dns_pack>) to the configured nameservers including	1105	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1106	response. It handles timeouts, retries and automatically falls back to
		1107	virtual circuit mode (TCP) when it receives a truncated reply.
		1108
1037	retries. Calls the callback with the decoded response packet if a reply	1109	Calls the callback with the decoded response packet if a reply was
1038	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
1039		1111
1040	=cut	1112	=cut
1041		1113
1042	sub request($$) {	1114	sub request($$) {
1043	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
1044		1116
1045	push @{ $self->{queue} }, [dns_pack $req, $cb];	1117	push @{ $self->{queue} }, [dns_pack $req, $cb];
1046	$self->_scheduler;	1118	$self->_scheduler;
1047	}	1119	}
1048		1120
1049	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
1050		1122
1051	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1123	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
1052	qtype of "*" is supported and means "any").	1124
		1125	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1126	a lowercase name (you have to look at the source to see which aliases are
		1127	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1128	more are known to this module). A C<$qtype> of "*" is supported and means
		1129	"any" record type.
1053		1130
1054	The callback will be invoked with a list of matching result records or	1131	The callback will be invoked with a list of matching result records or
1055	none on any error or if the name could not be found.	1132	none on any error or if the name could not be found.
1056		1133
1057	CNAME chains (although illegal) are followed up to a length of 8.	1134	CNAME chains (although illegal) are followed up to a length of 10.
		1135
		1136	The callback will be invoked with arraryefs of the form C<[$name, $type,
		1137	$class, @data>], where C<$name> is the domain name, C<$type> a type string
		1138	or number, C<$class> a class name and @data is resource-record-dependent
		1139	data. For C<a> records, this will be the textual IPv4 addresses, for C<ns>
		1140	or C<cname> records this will be a domain name, for C<txt> records these
		1141	are all the strings and so on.
		1142
		1143	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1144	decoded. All resource records not known to this module will have
		1145	the raw C<rdata> field as fourth entry.
1058		1146
1059	Note that this resolver is just a stub resolver: it requires a name server	1147	Note that this resolver is just a stub resolver: it requires a name server
1060	supporting recursive queries, will not do any recursive queries itself and	1148	supporting recursive queries, will not do any recursive queries itself and
1061	is not secure when used against an untrusted name server.	1149	is not secure when used against an untrusted name server.
1062		1150
…		…
1066		1154
1067	=item search => [$suffix...]	1155	=item search => [$suffix...]
1068		1156
1069	Use the given search list (which might be empty), by appending each one	1157	Use the given search list (which might be empty), by appending each one
1070	in turn to the C<$qname>. If this option is missing then the configured	1158	in turn to the C<$qname>. If this option is missing then the configured
1071	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1159	C<ndots> and C<search> values define its value (depending on C<ndots>, the
1072	then the searchlist will be ignored.	1160	empty suffix will be prepended or appended to that C<search> value). If
		1161	the C<$qname> ends in a dot, then the searchlist will be ignored.
1073		1162
1074	=item accept => [$type...]	1163	=item accept => [$type...]
1075		1164
1076	Lists the acceptable result types: only result types in this set will be	1165	Lists the acceptable result types: only result types in this set will be
1077	accepted and returned. The default includes the C<$qtype> and nothing	1166	accepted and returned. The default includes the C<$qtype> and nothing
1078	else.	1167	else. If this list includes C<cname>, then CNAME-chains will not be
		1168	followed (because you asked for the CNAME record).
1079		1169
1080	=item class => "class"	1170	=item class => "class"
1081		1171
1082	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1172	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
1083	hesiod are the only ones making sense). The default is "in", of course.	1173	hesiod are the only ones making sense). The default is "in", of course.
1084		1174
1085	=back	1175	=back
1086		1176
1087	Examples:	1177	Examples:
1088		1178
1089	$res->resolve ("ruth.plan9.de", "a", sub {	1179	# full example, you can paste this into perl:
1090	warn Dumper [@_];	1180	use Data::Dumper;
1091	});	1181	use AnyEvent::DNS;
		1182	AnyEvent::DNS::resolver->resolve (
		1183	"google.com", "*", my $cv = AnyEvent->condvar);
		1184	warn Dumper [$cv->recv];
1092		1185
		1186	# shortened result:
1093	[	1187	# [
		1188	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1189	# 2008052701, 7200, 1800, 1209600, 300 ],
1094	[	1190	# [
1095	'ruth.schmorp.de',	1191	# 'google.com', 'txt', 'in',
1096	'a',	1192	# 'v=spf1 include:_netblocks.google.com ~all'
1097	'in',	1193	# ],
1098	'129.13.162.95'	1194	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1195	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1196	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
1099	]	1197	# ]
		1198
		1199	# resolve a records:
		1200	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1201
		1202	# result:
		1203	# [
		1204	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
1100	]	1205	# ]
1101		1206
		1207	# resolve any records, but return only a and aaaa records:
1102	$res->resolve ("test1.laendle", "*",	1208	$res->resolve ("test1.laendle", "*",
1103	accept => ["a", "aaaa"],	1209	accept => ["a", "aaaa"],
1104	sub {	1210	sub {
1105	warn Dumper [@_];	1211	warn Dumper [@_];
1106	}	1212	}
1107	);	1213	);
1108		1214
1109	[	1215	# result:
1110	[	1216	# [
1111	'test1.laendle',	1217	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
1112	'a',	1218	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
1113	'in',
1114	'10.0.0.255'
1115	],
1116	[
1117	'test1.laendle',
1118	'aaaa',
1119	'in',
1120	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
1121	]	1219	# ]
1122	]
1123		1220
1124	=cut	1221	=cut
1125		1222
1126	sub resolve($%) {	1223	sub resolve($%) {
1127	my $cb = pop;	1224	my $cb = pop;
…		…
1147	$do_search = sub {	1244	$do_search = sub {
1148	@search	1245	@search
1149	or (undef $do_search), (undef $do_req), return $cb->();	1246	or (undef $do_search), (undef $do_req), return $cb->();
1150		1247
1151	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1248	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
1152	my $depth = 2;	1249	my $depth = 10;
1153		1250
1154	# advance in cname-chain	1251	# advance in cname-chain
1155	$do_req = sub {	1252	$do_req = sub {
1156	$self->request ({	1253	$self->request ({
1157	rd => 1,	1254	rd => 1,
…		…
1195	};	1292	};
1196		1293
1197	$do_search->();	1294	$do_search->();
1198	}	1295	}
1199		1296
		1297	=item $resolver->wait_for_slot ($cb->($resolver))
		1298
		1299	Wait until a free request slot is available and call the callback with the
		1300	resolver object.
		1301
		1302	A request slot is used each time a request is actually sent to the
		1303	nameservers: There are never more than C<max_outstanding> of them.
		1304
		1305	Although you can submit more requests (they will simply be queued until
		1306	a request slot becomes available), sometimes, usually for rate-limiting
		1307	purposes, it is useful to instead wait for a slot before generating the
		1308	request (or simply to know when the request load is low enough so one can
		1309	submit requests again).
		1310
		1311	This is what this method does: The callback will be called when submitting
		1312	a DNS request will not result in that request being queued. The callback
		1313	may or may not generate any requests in response.
		1314
		1315	Note that the callback will only be invoked when the request queue is
		1316	empty, so this does not play well if somebody else keeps the request queue
		1317	full at all times.
		1318
		1319	=cut
		1320
		1321	sub wait_for_slot {
		1322	my ($self, $cb) = @_;
		1323
		1324	push @{ $self->{wait} }, $cb;
		1325	$self->_scheduler;
		1326	}
		1327
1200	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end	1328	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
1201		1329
1202	1;	1330	1;
1203		1331
1204	=back	1332	=back
1205		1333
1206	=head1 AUTHOR	1334	=head1 AUTHOR
1207		1335
1208	Marc Lehmann <schmorp@schmorp.de>	1336	Marc Lehmann <schmorp@schmorp.de>
1209	http://home.schmorp.de/	1337	http://home.schmorp.de/
1210		1338
1211	=cut	1339	=cut
1212		1340

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.27 by root, Sat May 24 23:10:18 2008 UTC vs. Revision 1.88 by root, Mon Apr 20 14:34:18 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.27 by root, Sat May 24 23:10:18 2008 UTC vs.
Revision 1.88 by root, Mon Apr 20 14:34:18 2009 UTC