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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.18 by root, Fri May 23 22:52:31 2008 UTC vs.
Revision 1.86 by root, Fri Mar 27 10:49:50 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
		36	use AnyEvent ();
29	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
		38	use AnyEvent::Util qw(AF_INET6);
30		39
31	=item AnyEvent::DNS::addr $node, $service, $proto, $family, $type, $cb->([$family, $type, $proto, $sockaddr], ...)	40	our $VERSION = 4.35;
32		41
33	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
34
35	Tries to resolve the given nodename and service name into protocol families
36	and sockaddr structures usable to connect to this node and service in a
37	protocol-independent way. It works remotely similar to the getaddrinfo
38	posix function.
39
40	C<$node> is either an IPv4 or IPv6 address or a hostname, C<$service> is
41	either a service name (port name from F</etc/services>) or a numerical
42	port number. If both C<$node> and C<$service> are names, then SRV records
43	will be consulted to find the real service, otherwise they will be
44	used as-is. If you know that the service name is not in your services
45	database, then you cna specify the service in the format C<name=port>
46	(e.g. C<http=80>).
47
48	C<$proto> must be a protocol name, currently C<tcp>, C<udp> or
49	C<sctp>. The default is C<tcp>.
50
51	C<$family> must be either C<0> (meaning any protocol is ok), C<4> (use
52	only IPv4) or C<6> (use only IPv6).
53
54	C<$type> must be C<SOCK_STREAM>, C<SOCK_DGRAM> or C<SOCK_SEQPACKET> (or
55	C<undef> in which case it gets automatically chosen).
56
57	The callback will receive zero or more array references that contain
58	C<$family, $type, $proto> for use in C<socket> and a binary
59	C<$sockaddr> for use in C<connect> (or C<bind>).
60
61	The application should try these in the order given.
62
63	Example:
64
65	AnyEvent::DNS::addr "google.com", "http", 0, undef, undef, sub { ... };
66		43
67	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
68		45
69	Tries to resolve the given domain to IPv4 address(es).	46	Tries to resolve the given domain to IPv4 address(es).
70		47
…		…
88	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
89		66
90	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
91	of service records.	68	of service records.
92		69
93	Each srv_rr is an arrayref with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
94	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
95		72
96	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
97	should use the rfc algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
98		75
99	Example:	76	Example:
100		77
101	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
102	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
103		80
104	=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)
105		93
106	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)
107	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.
108		108
109	Example:	109	Example:
110		110
111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
112	# => f.root-servers.net	112	# => f.root-servers.net
113		113
114	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
115
116	Tries to resolve the given domain and passes all resource records found to
117	the callback.
118
119	=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
120		119
121	sub resolver;	120	sub resolver;
122		121
123	sub a($$) {	122	sub a($$) {
124	my ($domain, $cb) = @_;	123	my ($domain, $cb) = @_;
…		…
163	sub srv($$$$) {	162	sub srv($$$$) {
164	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
165		164
166	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
167	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
168	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
169	});	194	});
170	}	195	}
171		196
172	sub ptr($$) {	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($$) {
173	my ($ip, $cb) = @_;	239	my ($ip, $cb) = @_;
174		240
175	$ip = AnyEvent::Socket::parse_ip ($ip)	241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
176	or return $cb->();	242	or return $cb->();
177
178	if (4 == length $ip) {
179	$ip = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
180	} else {
181	$ip = join ".", (reverse split //, unpack "H*", $ip), "ip6.arpa.";
182	}
183		243
184	resolver->resolve ($ip => "ptr", sub {	244	resolver->resolve ($ip => "ptr", sub {
185	$cb->(map $_->[3], @_);	245	$cb->(map $_->[3], @_);
186	});	246	});
187	}	247	}
188		248
189	sub any($$) {	249	sub reverse_verify($$) {
190	my ($domain, $cb) = @_;	250	my ($ip, $cb) = @_;
191		251
192	resolver->resolve ($domain => "*", $cb);	252	my $ipn = AnyEvent::Socket::parse_address ($ip)
193	}
194
195	#############################################################################
196
197	#AnyEvent::DNS::addr $node, $service, $family, $type, $proto, $cb->([$family, $type, $protocol, $sockaddr], ...)
198
199	# $port, $host
200	sub pack_sockaddr_in6($$) {
201	pack "nnN a16 N",
202	Socket::AF_INET6,
203	$_[0], # port
204	0, # flowinfo
205	$_[1], # addr
206	0 # scope id
207	}
208
209	sub addr($$$$$$) {
210	my ($node, $service, $proto, $family, $type, $cb) = @_;
211
212	unless (eval { &Socket::AF_INET6 }) {
213	$family != 6
214	or return $cb->();	253	or return $cb->();
215	}
216		254
217	$proto \|\|= "tcp";	255	my $af = AnyEvent::Socket::address_family ($ipn);
218	$type \|\|= $proto eq "udp" ? Socket::SOCK_DGRAM : Socket::SOCK_STREAM;
219		256
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;
240	$cb->(map $_->[1], sort { $a->[0] <=> $b->[0] } @res)
241	});
242		259
243	$cv->begin;	260	my $ptr = _munge_ptr $ipn
244	for my $idx (0 .. $#target) {	261	or return $cb->();
245	my ($node, $port) = @{ $target[$idx] };
246		262
247	if (my $noden = AnyEvent::Socket::parse_ip ($node)) {	263	$ip = AnyEvent::Socket::format_address ($ipn); # normalise into the same form
248	if (4 == length $noden && $family != 6) {	264
249	push @res, [$idx, [Socket::AF_INET, $type, $proton,	265	ptr $ptr, sub {
250	Socket::pack_sockaddr_in $port, $noden]]	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;
251	}	274	}
252		275	$cb->(@res) unless --$cnt;
253	if (16 == length $noden && $family != 4) {
254	push @res, [$idx, [Socket::AF_INET6, $type, $proton,
255	pack_sockaddr_in6 $port, $noden]]
256	}
257	} else {
258	# ipv4
259	if ($family != 6) {
260	$cv->begin;
261	a $node, sub {
262	push @res, [$idx, [Socket::AF_INET, $type, $proton,
263	Socket::pack_sockaddr_in $port, AnyEvent::Socket::parse_ipv4 ($_)]]
264	for @_;
265	$cv->end;
266	};
267	}
268
269	my $idx = $idx + 0.5; # prefer ipv4 for now
270
271	# ipv6
272	if ($family != 4) {
273	$cv->begin;
274	aaaa $node, sub {
275	push @res, [$idx, [Socket::AF_INET6, $type, $proton,
276	pack_sockaddr_in6 $port, AnyEvent::Socket::parse_ipv6 ($_)]]
277	for @_;
278	$cv->end;
279	};
280	}
281	}	276	});
282	}	277	}
283	$cv->end;	278
		279	$cb->() unless $cnt;
284	};	280	};
285
286	# try srv records, if applicable
287	if (defined $service && !AnyEvent::Socket::parse_ip ($node)) {
288	srv $service, $proto, $node, sub {
289	my (@srv) = @_;
290
291	# no srv records, continue traditionally
292	@srv
293	or return &$resolve;
294
295	# only srv record has "." => abort
296	$srv[0][2] ne "." \|\| $#srv
297	or return $cb->();
298
299	# use srv records then
300	@target = map [$_->[3], $_->[2]],
301	grep $_->[3] ne ".",
302	@srv;
303
304	&$resolve;
305	};
306	} else {
307	&$resolve;
308	}
309	}	281	}
310		282
311	#############################################################################	283	#################################################################################
312		284
313	=back	285	=back
314		286
315	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS	287	=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS
316		288
317	=over 4	289	=over 4
318		290
319	=item $AnyEvent::DNS::EDNS0	291	=item $AnyEvent::DNS::EDNS0
320		292
321	This variable decides whether dns_pack automatically enables EDNS0	293	This variable decides whether dns_pack automatically enables EDNS0
322	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
323	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.
324		297
325	=cut	298	=cut
326		299
327	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
328		301
329	our %opcode_id = (	302	our %opcode_id = (
330	query => 0,	303	query => 0,
331	iquery => 1,	304	iquery => 1,
332	status => 2,	305	status => 2,
…		…
378	minfo => 14,	351	minfo => 14,
379	mx => 15,	352	mx => 15,
380	txt => 16,	353	txt => 16,
381	aaaa => 28,	354	aaaa => 28,
382	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
383	opt => 41,	357	opt => 41,
384	spf => 99,	358	spf => 99,
385	tkey => 249,	359	tkey => 249,
386	tsig => 250,	360	tsig => 250,
387	ixfr => 251,	361	ixfr => 251,
…		…
400	"*" => 255,	374	"*" => 255,
401	);	375	);
402		376
403	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
404		378
405	# names MUST have a trailing dot
406	sub _enc_qname($) {	379	sub _enc_name($) {
407	pack "(C/a)*", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
408	}	381	}
409		382
410	sub _enc_qd() {	383	sub _enc_qd() {
411	(_enc_qname $_->[0]) . pack "nn",	384	(_enc_name $_->[0]) . pack "nn",
412	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	385	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
413	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	386	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
414	}	387	}
415		388
416	sub _enc_rr() {	389	sub _enc_rr() {
417	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
418	}	391	}
419		392
420	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
421		394
422	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
423	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
424		397
425	Resource records are not yet encodable.	398	Resource records are not yet encodable.
426		399
427	Examples:	400	Examples:
428		401
429	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
430	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
431		404
432	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
433		406
434	{	407	{
435	id => 10000,	408	id => 10000,
436	op => "query",	409	op => "query",
437	rc => "nxdomain",	410	rc => "nxdomain",
438		411
439	# flags	412	# flags
440	qr => 1,	413	qr => 1,
441	aa => 0,	414	aa => 0,
442	tc => 0,	415	tc => 0,
443	rd => 0,	416	rd => 0,
444	ra => 0,	417	ra => 0,
445	ad => 0,	418	ad => 0,
446	cd => 0,	419	cd => 0,
447		420
448	qd => [@rr], # query section	421	qd => [@rr], # query section
449	an => [@rr], # answer section	422	an => [@rr], # answer section
450	ns => [@rr], # authority section	423	ns => [@rr], # authority section
451	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
452	}	425	}
453		426
454	=cut	427	=cut
455		428
456	sub dns_pack($) {	429	sub dns_pack($) {
457	my ($req) = @_;	430	my ($req) = @_;
…		…
470	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
471		444
472	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
473	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
474	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
475	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
476		449
477	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
478	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
479	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
480	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
481		454
482	($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
483	}	456	}
484		457
485	our $ofs;	458	our $ofs;
486	our $pkt;	459	our $pkt;
487		460
488	# bitches	461	# bitches
489	sub _dec_qname {	462	sub _dec_name {
490	my @res;	463	my @res;
491	my $redir;	464	my $redir;
492	my $ptr = $ofs;	465	my $ptr = $ofs;
493	my $cnt;	466	my $cnt;
494		467
495	while () {	468	while () {
496	return undef if ++$cnt >= 256; # to avoid DoS attacks	469	return undef if ++$cnt >= 256; # to avoid DoS attacks
497		470
498	my $len = ord substr $pkt, $ptr++, 1;	471	my $len = ord substr $pkt, $ptr++, 1;
499		472
500	if ($len & 0xc0) {	473	if ($len >= 0xc0) {
501	$ptr++;	474	$ptr++;
502	$ofs = $ptr if $ptr > $ofs;	475	$ofs = $ptr if $ptr > $ofs;
503	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	476	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
504	} elsif ($len) {	477	} elsif ($len) {
505	push @res, substr $pkt, $ptr, $len;	478	push @res, substr $pkt, $ptr, $len;
…		…
510	}	483	}
511	}	484	}
512	}	485	}
513		486
514	sub _dec_qd {	487	sub _dec_qd {
515	my $qname = _dec_qname;	488	my $qname = _dec_name;
516	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	489	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
517	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	490	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
518	}	491	}
519		492
520	our %dec_rr = (	493	our %dec_rr = (
521	1 => sub { join ".", unpack "C4" }, # a	494	1 => sub { join ".", unpack "C4", $_ }, # a
522	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	495	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
523	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	496	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
524	6 => sub {	497	6 => sub {
525	local $ofs = $ofs - length;	498	local $ofs = $ofs - length;
526	my $mname = _dec_qname;	499	my $mname = _dec_name;
527	my $rname = _dec_qname;	500	my $rname = _dec_name;
528	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	501	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
529	}, # soa	502	}, # soa
530	11 => sub { ((join ".", unpack "C4"), unpack "C a*", substr $_, 4) }, # wks	503	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
531	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	504	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
532	13 => sub { unpack "C/a C/a", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
533	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
534	16 => sub { unpack "(C/a)*", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
535	28 => sub { AnyEvent::Socket::format_ip ($_) }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
536	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	},
537	99 => sub { unpack "(C/a)*", $_ }, # spf	516	99 => sub { unpack "(C/a)", $_ }, # spf
538	);	517	);
539		518
540	sub _dec_rr {	519	sub _dec_rr {
541	my $qname = _dec_qname;	520	my $name = _dec_name;
542		521
543	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;
544	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	523	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
545		524
546	[	525	[
547	$qname,	526	$name,
548	$type_str{$rt} \|\| $rt,	527	$type_str{$rt} \|\| $rt,
549	$class_str{$rc} \|\| $rc,	528	$class_str{$rc} \|\| $rc,
550	($dec_rr{$rt} \|\| sub { $_ })->(),	529	($dec_rr{$rt} \|\| sub { $_ })->(),
551	]	530	]
552	}	531	}
…		…
555		534
556	Unpacks a DNS packet into a perl data structure.	535	Unpacks a DNS packet into a perl data structure.
557		536
558	Examples:	537	Examples:
559		538
560	# an unsuccessful reply	539	# an unsuccessful reply
561	{	540	{
562	'qd' => [	541	'qd' => [
563	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	542	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
564	],	543	],
565	'rc' => 'nxdomain',	544	'rc' => 'nxdomain',
566	'ar' => [],	545	'ar' => [],
567	'ns' => [	546	'ns' => [
568	[	547	[
569	'uni-karlsruhe.de',	548	'uni-karlsruhe.de',
570	'soa',	549	'soa',
571	'in',	550	'in',
572	'netserv.rz.uni-karlsruhe.de',	551	'netserv.rz.uni-karlsruhe.de',
573	'hostmaster.rz.uni-karlsruhe.de',	552	'hostmaster.rz.uni-karlsruhe.de',
574	2008052201, 10800, 1800, 2592000, 86400	553	2008052201, 10800, 1800, 2592000, 86400
575	]	554	]
576	],	555	],
577	'tc' => '',	556	'tc' => '',
578	'ra' => 1,	557	'ra' => 1,
579	'qr' => 1,	558	'qr' => 1,
580	'id' => 45915,	559	'id' => 45915,
581	'aa' => '',	560	'aa' => '',
582	'an' => [],	561	'an' => [],
583	'rd' => 1,	562	'rd' => 1,
584	'op' => 'query'	563	'op' => 'query'
585	}	564	}
586		565
587	# a successful reply	566	# a successful reply
588		567
589	{	568	{
590	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	569	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
591	'rc' => 0,	570	'rc' => 0,
592	'ar' => [	571	'ar' => [
593	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	572	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
594	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	573	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
595	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	574	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
596	],	575	],
597	'ns' => [	576	'ns' => [
598	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
599	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	578	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
600	],	579	],
601	'tc' => '',	580	'tc' => '',
602	'ra' => 1,	581	'ra' => 1,
603	'qr' => 1,	582	'qr' => 1,
604	'id' => 64265,	583	'id' => 64265,
605	'aa' => '',	584	'aa' => '',
606	'an' => [	585	'an' => [
607	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	586	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
608	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	587	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
609	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
610	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	589	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
611	],	590	],
612	'rd' => 1,	591	'rd' => 1,
613	'op' => 0	592	'op' => 0
614	}	593	}
615		594
616	=cut	595	=cut
617		596
618	sub dns_unpack($) {	597	sub dns_unpack($) {
619	local $pkt = shift;	598	local $pkt = shift;
…		…
690		669
691	=over 4	670	=over 4
692		671
693	=item server => [...]	672	=item server => [...]
694		673
695	A list of server addressses (default: C<v127.0.0.1>) in network format (4	674	A list of server addresses (default: C<v127.0.0.1>) in network format
696	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).
697		677
698	=item timeout => [...]	678	=item timeout => [...]
699		679
700	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
701	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,
…		…
710	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
711	tries to resolve the name without any suffixes first.	691	tries to resolve the name without any suffixes first.
712		692
713	=item max_outstanding => $integer	693	=item max_outstanding => $integer
714		694
715	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
716	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	696	option limits the number of outstanding requests to C<$integer>
717	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,
718	until some other requests have been resolved.	698	then the additional requests will be queued until some other requests have
		699	been resolved.
719		700
720	=item reuse => $seconds	701	=item reuse => $seconds
721		702
722	The number of seconds (default: C<60>) that a query id cannot be re-used	703	The number of seconds (default: C<300>) that a query id cannot be re-used
723	after a request. Since AnyEvent::DNS will only allocate up to 30000 ID's	704	after a timeout. If there was no time-out then query ids can be reused
724	at the same time, the long-term maximum number of requests per second is	705	immediately.
725	C<30000 / $seconds> (and thus C<500> requests/s by default).
726		706
727	=back	707	=back
728		708
729	=cut	709	=cut
730		710
731	sub new {	711	sub new {
732	my ($class, %arg) = @_;	712	my ($class, %arg) = @_;
733		713
734	socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0
735	or Carp::croak "socket: $!";
736
737	AnyEvent::Util::fh_nonblocking $fh, 1;
738
739	my $self = bless {	714	my $self = bless {
740	server => [v127.0.0.1],	715	server => [],
741	timeout => [2, 5, 5],	716	timeout => [2, 5, 5],
742	search => [],	717	search => [],
743	ndots => 1,	718	ndots => 1,
744	max_outstanding => 10,	719	max_outstanding => 10,
745	reuse => 60, # reuse id's after 5 minutes only, if possible	720	reuse => 300,
746	%arg,	721	%arg,
747	fh => $fh,
748	reuse_q => [],	722	reuse_q => [],
749	}, $class;	723	}, $class;
750		724
751	# search should default to gethostname's domain	725	# search should default to gethostname's domain
752	# but perl lacks a good posix module	726	# but perl lacks a good posix module
753		727
		728	# try to create an ipv4 and an ipv6 socket
		729	# only fail when we cannot create either
		730	my $got_socket;
		731
754	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;
755	$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";
756		760
757	$self->_compile;	761	$self->_compile;
758		762
759	$self	763	$self
760	}	764	}
761		765
762	=item $resolver->parse_resolv_conv ($string)	766	=item $resolver->parse_resolv_conv ($string)
763		767
764	Parses the given string a sif it were a F<resolv.conf> file. The following	768	Parses the given string as if it were a F<resolv.conf> file. The following
765	directives are supported (but not neecssarily implemented).	769	directives are supported (but not necessarily implemented).
766		770
767	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	771	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
768	C<options> (C<timeout>, C<attempts>, C<ndots>).	772	C<options> (C<timeout>, C<attempts>, C<ndots>).
769		773
770	Everything else is silently ignored.	774	Everything else is silently ignored.
…		…
782	for (split /\n/, $resolvconf) {	786	for (split /\n/, $resolvconf) {
783	if (/^\s*#/) {	787	if (/^\s*#/) {
784	# comment	788	# comment
785	} elsif (/^\snameserver\s+(\S+)\s$/i) {	789	} elsif (/^\snameserver\s+(\S+)\s$/i) {
786	my $ip = $1;	790	my $ip = $1;
787	if (AnyEvent::Util::dotted_quad $ip) {	791	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
788	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	792	push @{ $self->{server} }, $ipn;
789	} else {	793	} else {
790	warn "nameserver $ip invalid and ignored\n";	794	warn "nameserver $ip invalid and ignored\n";
791	}	795	}
792	} elsif (/^\sdomain\s+(\S)\s+$/i) {	796	} elsif (/^\sdomain\s+(\S)\s+$/i) {
793	$self->{search} = [$1];	797	$self->{search} = [$1];
…		…
816	$self->_compile;	820	$self->_compile;
817	}	821	}
818		822
819	=item $resolver->os_config	823	=item $resolver->os_config
820		824
821	Tries so load and parse F</etc/resolv.conf> on portable opertaing systems. Tries various	825	Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various
822	egregious hacks on windows to force the dns servers and searchlist out of the config.	826	egregious hacks on windows to force the DNS servers and searchlist out of the system.
823		827
824	=cut	828	=cut
825		829
826	sub os_config {	830	sub os_config {
827	my ($self) = @_;	831	my ($self) = @_;
828		832
829	if ($^O =~ /mswin32\|cygwin/i) {	833	$self->{server} = [];
830	# 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.
831		849
832	if (open my $fh, "ipconfig /all \|") {	850	if (open my $fh, "ipconfig /all \|") {
833	delete $self->{server};	851	# parsing strategy: we go through the output and look for
834	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).
835		855
		856	my $dns;
836	while (<$fh>) {	857	while (<$fh>) {
837	# first DNS.* is suffix list	858	if (s/^\s.\bdns\b.://i) {
838	if (/^\s*DNS/) {	859	$dns = 1;
839	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 {
840	push @{ $self->{search} }, $1;	869	push @{ $self->{search} }, $s;
841	$_ = <$fh>;
842	}	870	}
843	last;
844	}	871	}
845	}	872	}
846		873
847	while (<$fh>) {	874	# always add one fallback server
848	# second DNS.* is server address list	875	push @{ $self->{server} }, $DNS_FALLBACK[rand @DNS_FALLBACK];
849	if (/^\s*DNS/) {
850	while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) {
851	my $ip = $1;
852	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip
853	if AnyEvent::Util::dotted_quad $ip;
854	$_ = <$fh>;
855	}
856	last;
857	}
858	}
859		876
860	$self->_compile;	877	$self->_compile;
861	}	878	}
862	} else {	879	} else {
863	# try resolv.conf everywhere	880	# try resolv.conf everywhere
…		…
867	$self->parse_resolv_conf (<$fh>);	884	$self->parse_resolv_conf (<$fh>);
868	}	885	}
869	}	886	}
870	}	887	}
871		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
872	sub _compile {	917	sub _compile {
873	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	}
874		927
875	my @retry;	928	my @retry;
876		929
877	for my $timeout (@{ $self->{timeout} }) {	930	for my $timeout (@{ $self->{timeout} }) {
878	for my $server (@{ $self->{server} }) {	931	for my $server (@{ $self->{server} }) {
…		…
896	$NOW = time;	949	$NOW = time;
897	$id->[1]->($res);	950	$id->[1]->($res);
898	}	951	}
899		952
900	sub _recv {	953	sub _recv {
901	my ($self) = @_;	954	my ($self, $pkt, $peer) = @_;
902		955
903	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
904	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	959	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
905		960
906	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	961	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
907		962
908	$self->_feed ($res);	963	$self->_feed ($pkt);
909	}
910	}	964	}
911		965
		966	sub _free_id {
		967	my ($self, $id, $timeout) = @_;
		968
		969	if ($timeout) {
		970	# we need to block the id for a while
		971	$self->{id}{$id} = 1;
		972	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		973	} else {
		974	# we can quickly recycle the id
		975	delete $self->{id}{$id};
		976	}
		977
		978	--$self->{outstanding};
		979	$self->_scheduler;
		980	}
		981
		982	# execute a single request, involves sending it with timeouts to multiple servers
912	sub _exec {	983	sub _exec {
913	my ($self, $req, $retry) = @_;	984	my ($self, $req) = @_;
914		985
		986	my $retry; # of retries
		987	my $do_retry;
		988
		989	$do_retry = sub {
915	if (my $retry_cfg = $self->{retry}[$retry]) {	990	my $retry_cfg = $self->{retry}[$retry++]
		991	or do {
		992	# failure
		993	$self->_free_id ($req->[2], $retry > 1);
		994	undef $do_retry; return $req->[1]->();
		995	};
		996
916	my ($server, $timeout) = @$retry_cfg;	997	my ($server, $timeout) = @$retry_cfg;
917		998
918	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	999	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
919	$NOW = time;	1000	$NOW = time;
920		1001
921	# timeout, try next	1002	# timeout, try next
922	$self->_exec ($req, $retry + 1);	1003	&$do_retry if $do_retry;
923	}), sub {	1004	}), sub {
924	my ($res) = @_;	1005	my ($res) = @_;
925		1006
926	if ($res->{tc}) {	1007	if ($res->{tc}) {
927	# success, but truncated, so use tcp	1008	# success, but truncated, so use tcp
928	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
929	my ($fh) = @_	1012	my ($fh) = @_
930	or return $self->_exec ($req, $retry + 1);	1013	or return &$do_retry;
931		1014
932	my $handle = new AnyEvent::Handle	1015	my $handle; $handle = new AnyEvent::Handle
933	fh => $fh,	1016	fh => $fh,
		1017	timeout => $timeout,
934	on_error => sub {	1018	on_error => sub {
		1019	undef $handle;
		1020	return unless $do_retry; # some other request could have invalidated us already
935	# failure, try next	1021	# failure, try next
936	$self->_exec ($req, $retry + 1);	1022	&$do_retry;
937	};	1023	};
938		1024
939	$handle->push_write (pack "n/a", $req->[0]);	1025	$handle->push_write (pack "n/a", $req->[0]);
940	$handle->push_read_chunk (2, sub {	1026	$handle->push_read (chunk => 2, sub {
941	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1027	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1028	undef $handle;
942	$self->_feed ($_[1]);	1029	$self->_feed ($_[1]);
943	});	1030	});
944	});	1031	});
945	shutdown $fh, 1;
946		1032
947	}, sub { $timeout });	1033	}, sub { $timeout });
948		1034
949	} else {	1035	} else {
950	# success	1036	# success
951	$self->{id}{$req->[2]} = 1;	1037	$self->_free_id ($req->[2], $retry > 1);
952	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1038	undef $do_retry; return $req->[1]->($res);
953	--$self->{outstanding};
954	$self->_scheduler;
955
956	$req->[1]->($res);
957	}	1039	}
958	}];	1040	}];
		1041
		1042	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
959		1043
960	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1044	my $fh = AF_INET == Socket::sockaddr_family ($sa)
961	} else {	1045	? $self->{fh4} : $self->{fh6}
962	# failure	1046	or return &$do_retry;
963	$self->{id}{$req->[2]} = 1;
964	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];
965	--$self->{outstanding};
966	$self->_scheduler;
967		1047
968	$req->[1]->();	1048	send $fh, $req->[0], 0, $sa;
969	}	1049	};
		1050
		1051	&$do_retry;
970	}	1052	}
971		1053
972	sub _scheduler {	1054	sub _scheduler {
973	my ($self) = @_;	1055	my ($self) = @_;
		1056
		1057	no strict 'refs';
974		1058
975	$NOW = time;	1059	$NOW = time;
976		1060
977	# first clear id reuse queue	1061	# first clear id reuse queue
978	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1062	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
987	$self->_scheduler;	1071	$self->_scheduler;
988	});	1072	});
989	last;	1073	last;
990	}	1074	}
991		1075
992	my $req = shift @{ $self->{queue} }	1076	if (my $req = shift @{ $self->{queue} }) {
993	or last;	1077	# found a request in the queue, execute it
994
995	while () {	1078	while () {
996	$req->[2] = int rand 65536;	1079	$req->[2] = int rand 65536;
997	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;
998	}	1096	}
999
1000	$self->{id}{$req->[2]} = 1;
1001	substr $req->[0], 0, 2, pack "n", $req->[2];
1002
1003	++$self->{outstanding};
1004	$self->_exec ($req, 0);
1005	}	1097	}
1006	}	1098	}
1007		1099
1008	=item $resolver->request ($req, $cb->($res))	1100	=item $resolver->request ($req, $cb->($res))
1009		1101
		1102	This is the main low-level workhorse for sending DNS requests.
		1103
1010	Sends a single request (a hash-ref formated as specified for	1104	This function sends a single request (a hash-ref formated as specified
1011	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
1012	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
1013	was received, or no arguments on timeout.	1110	received, or no arguments in case none of the servers answered.
1014		1111
1015	=cut	1112	=cut
1016		1113
1017	sub request($$) {	1114	sub request($$) {
1018	my ($self, $req, $cb) = @_;	1115	my ($self, $req, $cb) = @_;
1019		1116
1020	push @{ $self->{queue} }, [dns_pack $req, $cb];	1117	push @{ $self->{queue} }, [dns_pack $req, $cb];
1021	$self->_scheduler;	1118	$self->_scheduler;
1022	}	1119	}
1023		1120
1024	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1121	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
1025		1122
1026	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1123	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
1027	qtype of "*" is supported and means "any").	1124
		1125	A C<$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<$qtype> of "*" is supported and means
		1129	"any" record type.
1028		1130
1029	The callback will be invoked with a list of matching result records or	1131	The callback will be invoked with a list of matching result records or
1030	none on any error or if the name could not be found.	1132	none on any error or if the name could not be found.
1031		1133
1032	CNAME chains (although illegal) are followed up to a length of 8.	1134	CNAME chains (although illegal) are followed up to a length of 10.
1033		1135
		1136	The callback will be invoked with arraryefs of the form C<[$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.
		1146
1034	Note that this resolver is just a stub resolver: it requires a nameserver	1147	Note that this resolver is just a stub resolver: it requires a name server
1035	supporting recursive queries, will not do any recursive queries itself and	1148	supporting recursive queries, will not do any recursive queries itself and
1036	is not secure when used against an untrusted name server.	1149	is not secure when used against an untrusted name server.
1037		1150
1038	The following options are supported:	1151	The following options are supported:
1039		1152
…		…
1041		1154
1042	=item search => [$suffix...]	1155	=item search => [$suffix...]
1043		1156
1044	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
1045	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
1046	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1159	C<ndots> and C<search> values define its value (depending on C<ndots>, the
1047	then the searchlist will be ignored.	1160	empty suffix will be prepended or appended to that C<search> value). If
		1161	the C<$qname> ends in a dot, then the searchlist will be ignored.
1048		1162
1049	=item accept => [$type...]	1163	=item accept => [$type...]
1050		1164
1051	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
1052	accepted and returned. The default includes the C<$qtype> and nothing	1166	accepted and returned. The default includes the C<$qtype> and nothing
1053	else.	1167	else. If this list includes C<cname>, then CNAME-chains will not be
		1168	followed (because you asked for the CNAME record).
1054		1169
1055	=item class => "class"	1170	=item class => "class"
1056		1171
1057	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
1058	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.
1059		1174
1060	=back	1175	=back
1061		1176
1062	Examples:	1177	Examples:
1063		1178
1064	$res->resolve ("ruth.plan9.de", "a", sub {	1179	# full example, you can paste this into perl:
1065	warn Dumper [@_];	1180	use Data::Dumper;
1066	});	1181	use AnyEvent::DNS;
		1182	AnyEvent::DNS::resolver->resolve (
		1183	"google.com", "*", my $cv = AnyEvent->condvar);
		1184	warn Dumper [$cv->recv];
1067		1185
		1186	# shortened result:
1068	[	1187	# [
		1188	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1189	# 2008052701, 7200, 1800, 1209600, 300 ],
1069	[	1190	# [
1070	'ruth.schmorp.de',	1191	# 'google.com', 'txt', 'in',
1071	'a',	1192	# 'v=spf1 include:_netblocks.google.com ~all'
1072	'in',	1193	# ],
1073	'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' ],
1074	]	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' ]
1075	]	1205	# ]
1076		1206
		1207	# resolve any records, but return only a and aaaa records:
1077	$res->resolve ("test1.laendle", "*",	1208	$res->resolve ("test1.laendle", "*",
1078	accept => ["a", "aaaa"],	1209	accept => ["a", "aaaa"],
1079	sub {	1210	sub {
1080	warn Dumper [@_];	1211	warn Dumper [@_];
1081	}	1212	}
1082	);	1213	);
1083		1214
1084	[	1215	# result:
1085	[	1216	# [
1086	'test1.laendle',	1217	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
1087	'a',	1218	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
1088	'in',
1089	'10.0.0.255'
1090	],
1091	[
1092	'test1.laendle',
1093	'aaaa',
1094	'in',
1095	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
1096	]	1219	# ]
1097	]
1098		1220
1099	=cut	1221	=cut
1100		1222
1101	sub resolve($%) {	1223	sub resolve($%) {
1102	my $cb = pop;	1224	my $cb = pop;
…		…
1115	my %atype = $opt{accept}	1237	my %atype = $opt{accept}
1116	? map +($_ => 1), @{ $opt{accept} }	1238	? map +($_ => 1), @{ $opt{accept} }
1117	: ($qtype => 1);	1239	: ($qtype => 1);
1118		1240
1119	# advance in searchlist	1241	# advance in searchlist
1120	my $do_search; $do_search = sub {	1242	my ($do_search, $do_req);
		1243
		1244	$do_search = sub {
1121	@search	1245	@search
1122	or return $cb->();	1246	or (undef $do_search), (undef $do_req), return $cb->();
1123		1247
1124	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1248	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
1125	my $depth = 2;	1249	my $depth = 10;
1126		1250
1127	# advance in cname-chain	1251	# advance in cname-chain
1128	my $do_req; $do_req = sub {	1252	$do_req = sub {
1129	$self->request ({	1253	$self->request ({
1130	rd => 1,	1254	rd => 1,
1131	qd => [[$name, $qtype, $class]],	1255	qd => [[$name, $qtype, $class]],
1132	}, sub {	1256	}, sub {
1133	my ($res) = @_	1257	my ($res) = @_
…		…
1137		1261
1138	while () {	1262	while () {
1139	# results found?	1263	# results found?
1140	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1264	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
1141		1265
1142	return $cb->(@rr)	1266	(undef $do_search), (undef $do_req), return $cb->(@rr)
1143	if @rr;	1267	if @rr;
1144		1268
1145	# see if there is a cname we can follow	1269	# see if there is a cname we can follow
1146	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1270	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
1147		1271
…		…
1168	};	1292	};
1169		1293
1170	$do_search->();	1294	$do_search->();
1171	}	1295	}
1172		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
1173	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
1174		1329
1175	1;	1330	1;
1176		1331
1177	=back	1332	=back
1178		1333
1179	=head1 AUTHOR	1334	=head1 AUTHOR
1180		1335
1181	Marc Lehmann <schmorp@schmorp.de>	1336	Marc Lehmann <schmorp@schmorp.de>
1182	http://home.schmorp.de/	1337	http://home.schmorp.de/
1183		1338
1184	=cut	1339	=cut
1185		1340

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.18 by root, Fri May 23 22:52:31 2008 UTC vs. Revision 1.86 by root, Fri Mar 27 10:49:50 2009 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.18 by root, Fri May 23 22:52:31 2008 UTC vs.
Revision 1.86 by root, Fri Mar 27 10:49:50 2009 UTC