[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 1.95 by root, Fri Jun 26 06:33:17 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 $VERSION = 4.42;
32		41
33	NOT YET IMPLEMENTED	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
34
35	Tries to resolve the given nodename and service name into protocol families
36	and sockaddr structures usable to connect to this node and service in a
37	protocol-independent way. It works remotely similar to the getaddrinfo
38	posix function.
39
40	C<$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
		357	dname => 39, # rfc2672
383	opt => 41,	358	opt => 41,
384	spf => 99,	359	spf => 99,
385	tkey => 249,	360	tkey => 249,
386	tsig => 250,	361	tsig => 250,
387	ixfr => 251,	362	ixfr => 251,
…		…
400	"*" => 255,	375	"*" => 255,
401	);	376	);
402		377
403	our %class_str = reverse %class_id;	378	our %class_str = reverse %class_id;
404		379
405	# names MUST have a trailing dot
406	sub _enc_qname($) {	380	sub _enc_name($) {
407	pack "(C/a)*", (split /\./, shift), ""	381	pack "(C/a)", (split /\./, shift), ""
408	}	382	}
409		383
410	sub _enc_qd() {	384	sub _enc_qd() {
411	(_enc_qname $_->[0]) . pack "nn",	385	(_enc_name $_->[0]) . pack "nn",
412	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),	386	($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}),
413	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})	387	($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] \|\| "in"})
414	}	388	}
415		389
416	sub _enc_rr() {	390	sub _enc_rr() {
417	die "encoding of resource records is not supported";	391	die "encoding of resource records is not supported";
418	}	392	}
419		393
420	=item $pkt = AnyEvent::DNS::dns_pack $dns	394	=item $pkt = AnyEvent::DNS::dns_pack $dns
421		395
422	Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly	396	Packs a perl data structure into a DNS packet. Reading RFC 1035 is strongly
423	recommended, then everything will be totally clear. Or maybe not.	397	recommended, then everything will be totally clear. Or maybe not.
424		398
425	Resource records are not yet encodable.	399	Resource records are not yet encodable.
426		400
427	Examples:	401	Examples:
428		402
429	# very simple request, using lots of default values:	403	# very simple request, using lots of default values:
430	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	404	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
431		405
432	# more complex example, showing how flags etc. are named:	406	# more complex example, showing how flags etc. are named:
433		407
434	{	408	{
435	id => 10000,	409	id => 10000,
436	op => "query",	410	op => "query",
437	rc => "nxdomain",	411	rc => "nxdomain",
438		412
439	# flags	413	# flags
440	qr => 1,	414	qr => 1,
441	aa => 0,	415	aa => 0,
442	tc => 0,	416	tc => 0,
443	rd => 0,	417	rd => 0,
444	ra => 0,	418	ra => 0,
445	ad => 0,	419	ad => 0,
446	cd => 0,	420	cd => 0,
447		421
448	qd => [@rr], # query section	422	qd => [@rr], # query section
449	an => [@rr], # answer section	423	an => [@rr], # answer section
450	ns => [@rr], # authority section	424	ns => [@rr], # authority section
451	ar => [@rr], # additional records section	425	ar => [@rr], # additional records section
452	}	426	}
453		427
454	=cut	428	=cut
455		429
456	sub dns_pack($) {	430	sub dns_pack($) {
457	my ($req) = @_;	431	my ($req) = @_;
…		…
470	+ $rcode_id{$req->{rc}} * 0x0001,	444	+ $rcode_id{$req->{rc}} * 0x0001,
471		445
472	scalar @{ $req->{qd} \|\| [] },	446	scalar @{ $req->{qd} \|\| [] },
473	scalar @{ $req->{an} \|\| [] },	447	scalar @{ $req->{an} \|\| [] },
474	scalar @{ $req->{ns} \|\| [] },	448	scalar @{ $req->{ns} \|\| [] },
475	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	449	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
476		450
477	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	451	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
478	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
479	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
480	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	454	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
481		455
482	($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size	456	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
483	}	457	}
484		458
485	our $ofs;	459	our $ofs;
486	our $pkt;	460	our $pkt;
487		461
488	# bitches	462	# bitches
489	sub _dec_qname {	463	sub _dec_name {
490	my @res;	464	my @res;
491	my $redir;	465	my $redir;
492	my $ptr = $ofs;	466	my $ptr = $ofs;
493	my $cnt;	467	my $cnt;
494		468
495	while () {	469	while () {
496	return undef if ++$cnt >= 256; # to avoid DoS attacks	470	return undef if ++$cnt >= 256; # to avoid DoS attacks
497		471
498	my $len = ord substr $pkt, $ptr++, 1;	472	my $len = ord substr $pkt, $ptr++, 1;
499		473
500	if ($len & 0xc0) {	474	if ($len >= 0xc0) {
501	$ptr++;	475	$ptr++;
502	$ofs = $ptr if $ptr > $ofs;	476	$ofs = $ptr if $ptr > $ofs;
503	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;	477	$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff;
504	} elsif ($len) {	478	} elsif ($len) {
505	push @res, substr $pkt, $ptr, $len;	479	push @res, substr $pkt, $ptr, $len;
…		…
510	}	484	}
511	}	485	}
512	}	486	}
513		487
514	sub _dec_qd {	488	sub _dec_qd {
515	my $qname = _dec_qname;	489	my $qname = _dec_name;
516	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;	490	my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4;
517	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]	491	[$qname, $type_str{$qt} \|\| $qt, $class_str{$qc} \|\| $qc]
518	}	492	}
519		493
520	our %dec_rr = (	494	our %dec_rr = (
521	1 => sub { join ".", unpack "C4" }, # a	495	1 => sub { join ".", unpack "C4", $_ }, # a
522	2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns	496	2 => sub { local $ofs = $ofs - length; _dec_name }, # ns
523	5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname	497	5 => sub { local $ofs = $ofs - length; _dec_name }, # cname
524	6 => sub {	498	6 => sub {
525	local $ofs = $ofs - length;	499	local $ofs = $ofs - length;
526	my $mname = _dec_qname;	500	my $mname = _dec_name;
527	my $rname = _dec_qname;	501	my $rname = _dec_name;
528	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)	502	($mname, $rname, unpack "NNNNN", substr $pkt, $ofs)
529	}, # soa	503	}, # soa
530	11 => sub { ((join ".", unpack "C4"), unpack "C a*", substr $_, 4) }, # wks	504	11 => sub { ((join ".", unpack "C4", $_), unpack "C a*", substr $_, 4) }, # wks
531	12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr	505	12 => sub { local $ofs = $ofs - length; _dec_name }, # ptr
532	13 => sub { unpack "C/a C/a", $_ }, # hinfo	506	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
533	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx	507	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
534	16 => sub { unpack "(C/a)*", $_ }, # txt	508	16 => sub { unpack "(C/a)", $_ }, # txt
535	28 => sub { AnyEvent::Socket::format_ip ($_) }, # aaaa	509	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
536	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv	510	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		511	35 => sub { # naptr
		512	# requires perl 5.10, sorry
		513	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		514	local $ofs = $ofs + $offset - length;
		515	($order, $preference, $flags, $service, $regexp, _dec_name)
		516	},
		517	39 => sub { local $ofs = $ofs - length; _dec_name }, # dname
537	99 => sub { unpack "(C/a)*", $_ }, # spf	518	99 => sub { unpack "(C/a)", $_ }, # spf
538	);	519	);
539		520
540	sub _dec_rr {	521	sub _dec_rr {
541	my $qname = _dec_qname;	522	my $name = _dec_name;
542		523
543	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;	524	my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10;
544	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;	525	local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen;
545		526
546	[	527	[
547	$qname,	528	$name,
548	$type_str{$rt} \|\| $rt,	529	$type_str{$rt} \|\| $rt,
549	$class_str{$rc} \|\| $rc,	530	$class_str{$rc} \|\| $rc,
550	($dec_rr{$rt} \|\| sub { $_ })->(),	531	($dec_rr{$rt} \|\| sub { $_ })->(),
551	]	532	]
552	}	533	}
…		…
555		536
556	Unpacks a DNS packet into a perl data structure.	537	Unpacks a DNS packet into a perl data structure.
557		538
558	Examples:	539	Examples:
559		540
560	# an unsuccessful reply	541	# an unsuccessful reply
561	{	542	{
562	'qd' => [	543	'qd' => [
563	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	544	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
564	],	545	],
565	'rc' => 'nxdomain',	546	'rc' => 'nxdomain',
566	'ar' => [],	547	'ar' => [],
567	'ns' => [	548	'ns' => [
568	[	549	[
569	'uni-karlsruhe.de',	550	'uni-karlsruhe.de',
570	'soa',	551	'soa',
571	'in',	552	'in',
572	'netserv.rz.uni-karlsruhe.de',	553	'netserv.rz.uni-karlsruhe.de',
573	'hostmaster.rz.uni-karlsruhe.de',	554	'hostmaster.rz.uni-karlsruhe.de',
574	2008052201, 10800, 1800, 2592000, 86400	555	2008052201, 10800, 1800, 2592000, 86400
575	]	556	]
576	],	557	],
577	'tc' => '',	558	'tc' => '',
578	'ra' => 1,	559	'ra' => 1,
579	'qr' => 1,	560	'qr' => 1,
580	'id' => 45915,	561	'id' => 45915,
581	'aa' => '',	562	'aa' => '',
582	'an' => [],	563	'an' => [],
583	'rd' => 1,	564	'rd' => 1,
584	'op' => 'query'	565	'op' => 'query'
585	}	566	}
586		567
587	# a successful reply	568	# a successful reply
588		569
589	{	570	{
590	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	571	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
591	'rc' => 0,	572	'rc' => 0,
592	'ar' => [	573	'ar' => [
593	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	574	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
594	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	575	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
595	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	576	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
596	],	577	],
597	'ns' => [	578	'ns' => [
598	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	579	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
599	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	580	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
600	],	581	],
601	'tc' => '',	582	'tc' => '',
602	'ra' => 1,	583	'ra' => 1,
603	'qr' => 1,	584	'qr' => 1,
604	'id' => 64265,	585	'id' => 64265,
605	'aa' => '',	586	'aa' => '',
606	'an' => [	587	'an' => [
607	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	588	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
608	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	589	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
609	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	590	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
610	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	591	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
611	],	592	],
612	'rd' => 1,	593	'rd' => 1,
613	'op' => 0	594	'op' => 0
614	}	595	}
615		596
616	=cut	597	=cut
617		598
618	sub dns_unpack($) {	599	sub dns_unpack($) {
619	local $pkt = shift;	600	local $pkt = shift;
…		…
674		655
675	our $RESOLVER;	656	our $RESOLVER;
676		657
677	sub resolver() {	658	sub resolver() {
678	$RESOLVER \|\| do {	659	$RESOLVER \|\| do {
679	$RESOLVER = new AnyEvent::DNS;	660	$RESOLVER = new AnyEvent::DNS untaint => 1;
680	$RESOLVER->os_config;	661	$RESOLVER->os_config;
681	$RESOLVER	662	$RESOLVER
682	}	663	}
683	}	664	}
684		665
…		…
690		671
691	=over 4	672	=over 4
692		673
693	=item server => [...]	674	=item server => [...]
694		675
695	A list of server addressses (default: C<v127.0.0.1>) in network format (4	676	A list of server addresses (default: C<v127.0.0.1>) in network format
696	octets for IPv4, 16 octets for IPv6 - not yet supported).	677	(i.e. as returned by C<AnyEvent::Socket::parse_address> - both IPv4 and
		678	IPv6 are supported).
697		679
698	=item timeout => [...]	680	=item timeout => [...]
699		681
700	A list of timeouts to use (also determines the number of retries). To make	682	A list of timeouts to use (also determines the number of retries). To make
701	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,	683	three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2,
…		…
710	The number of dots (default: C<1>) that a name must have so that the resolver	692	The number of dots (default: C<1>) that a name must have so that the resolver
711	tries to resolve the name without any suffixes first.	693	tries to resolve the name without any suffixes first.
712		694
713	=item max_outstanding => $integer	695	=item max_outstanding => $integer
714		696
715	Most name servers do not handle many parallel requests very well. This option	697	Most name servers do not handle many parallel requests very well. This
716	limits the numbe rof outstanding requests to C<$n> (default: C<10>), that means	698	option limits the number of outstanding requests to C<$integer>
717	if you request more than this many requests, then the additional requests will be queued	699	(default: C<10>), that means if you request more than this many requests,
718	until some other requests have been resolved.	700	then the additional requests will be queued until some other requests have
		701	been resolved.
719		702
720	=item reuse => $seconds	703	=item reuse => $seconds
721		704
722	The number of seconds (default: C<60>) that a query id cannot be re-used	705	The number of seconds (default: C<300>) that a query id cannot be re-used
723	after a request. Since AnyEvent::DNS will only allocate up to 30000 ID's	706	after a timeout. If there was no time-out then query ids can be reused
724	at the same time, the long-term maximum number of requests per second is	707	immediately.
725	C<30000 / $seconds> (and thus C<500> requests/s by default).	708
		709	=item untaint => $boolean
		710
		711	When true, then the resolver will automatically untaint results, and might
		712	also ignore certain environment variables.
726		713
727	=back	714	=back
728		715
729	=cut	716	=cut
730		717
731	sub new {	718	sub new {
732	my ($class, %arg) = @_;	719	my ($class, %arg) = @_;
733		720
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 {	721	my $self = bless {
740	server => [v127.0.0.1],	722	server => [],
741	timeout => [2, 5, 5],	723	timeout => [2, 5, 5],
742	search => [],	724	search => [],
743	ndots => 1,	725	ndots => 1,
744	max_outstanding => 10,	726	max_outstanding => 10,
745	reuse => 60, # reuse id's after 5 minutes only, if possible	727	reuse => 300,
746	%arg,	728	%arg,
747	fh => $fh,
748	reuse_q => [],	729	reuse_q => [],
749	}, $class;	730	}, $class;
750		731
751	# search should default to gethostname's domain	732	# search should default to gethostname's domain
752	# but perl lacks a good posix module	733	# but perl lacks a good posix module
753		734
		735	# try to create an ipv4 and an ipv6 socket
		736	# only fail when we cannot create either
		737	my $got_socket;
		738
754	Scalar::Util::weaken (my $wself = $self);	739	Scalar::Util::weaken (my $wself = $self);
		740
		741	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		742	++$got_socket;
		743
		744	AnyEvent::Util::fh_nonblocking $fh4, 1;
		745	$self->{fh4} = $fh4;
755	$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv });	746	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
		747	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
		748	$wself->_recv ($pkt, $peer);
		749	}
		750	});
		751	}
		752
		753	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		754	++$got_socket;
		755
		756	$self->{fh6} = $fh6;
		757	AnyEvent::Util::fh_nonblocking $fh6, 1;
		758	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
		759	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
		760	$wself->_recv ($pkt, $peer);
		761	}
		762	});
		763	}
		764
		765	$got_socket
		766	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
756		767
757	$self->_compile;	768	$self->_compile;
758		769
759	$self	770	$self
760	}	771	}
761		772
762	=item $resolver->parse_resolv_conv ($string)	773	=item $resolver->parse_resolv_conv ($string)
763		774
764	Parses the given string a sif it were a F<resolv.conf> file. The following	775	Parses the given string as if it were a F<resolv.conf> file. The following
765	directives are supported (but not neecssarily implemented).	776	directives are supported (but not necessarily implemented).
766		777
767	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,	778	C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>,
768	C<options> (C<timeout>, C<attempts>, C<ndots>).	779	C<options> (C<timeout>, C<attempts>, C<ndots>).
769		780
770	Everything else is silently ignored.	781	Everything else is silently ignored.
…		…
782	for (split /\n/, $resolvconf) {	793	for (split /\n/, $resolvconf) {
783	if (/^\s*#/) {	794	if (/^\s*#/) {
784	# comment	795	# comment
785	} elsif (/^\snameserver\s+(\S+)\s$/i) {	796	} elsif (/^\snameserver\s+(\S+)\s$/i) {
786	my $ip = $1;	797	my $ip = $1;
787	if (AnyEvent::Util::dotted_quad $ip) {	798	if (my $ipn = AnyEvent::Socket::parse_address ($ip)) {
788	push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip;	799	push @{ $self->{server} }, $ipn;
789	} else {	800	} else {
790	warn "nameserver $ip invalid and ignored\n";	801	warn "nameserver $ip invalid and ignored\n";
791	}	802	}
792	} elsif (/^\sdomain\s+(\S)\s+$/i) {	803	} elsif (/^\sdomain\s+(\S)\s+$/i) {
793	$self->{search} = [$1];	804	$self->{search} = [$1];
…		…
816	$self->_compile;	827	$self->_compile;
817	}	828	}
818		829
819	=item $resolver->os_config	830	=item $resolver->os_config
820		831
821	Tries so load and parse F</etc/resolv.conf> on portable opertaing systems. Tries various	832	Tries so load and parse F</etc/resolv.conf> on portable operating
822	egregious hacks on windows to force the dns servers and searchlist out of the config.	833	systems. Tries various egregious hacks on windows to force the DNS servers
		834	and searchlist out of the system.
823		835
824	=cut	836	=cut
825		837
826	sub os_config {	838	sub os_config {
827	my ($self) = @_;	839	my ($self) = @_;
828		840
829	if ($^O =~ /mswin32\|cygwin/i) {	841	$self->{server} = [];
830	# yeah, it suxx... lets hope DNS is DNS in all locales	842	$self->{search} = [];
		843
		844	if (AnyEvent::WIN32 \|\| $^O =~ /cygwin/i) {
		845	no strict 'refs';
		846
		847	# there are many options to find the current nameservers etc. on windows
		848	# all of them don't work consistently:
		849	# - the registry thing needs separate code on win32 native vs. cygwin
		850	# - the registry layout differs between windows versions
		851	# - calling windows api functions doesn't work on cygwin
		852	# - ipconfig uses locale-specific messages
		853
		854	# we use ipconfig parsing because, despite all its brokenness,
		855	# it seems most stable in practise.
		856	# for good measure, we append a fallback nameserver to our list.
831		857
832	if (open my $fh, "ipconfig /all \|") {	858	if (open my $fh, "ipconfig /all \|") {
833	delete $self->{server};	859	# parsing strategy: we go through the output and look for
834	delete $self->{search};	860	# :-lines with DNS in them. everything in those is regarded as
		861	# either a nameserver (if it parses as an ip address), or a suffix
		862	# (all else).
835		863
		864	my $dns;
836	while (<$fh>) {	865	while (<$fh>) {
837	# first DNS.* is suffix list	866	if (s/^\s.\bdns\b.://i) {
838	if (/^\s*DNS/) {	867	$dns = 1;
839	while (/\s+([[:alnum:].\-]+)\s*$/) {	868	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
		869	$dns = 0;
		870	}
		871	if ($dns && /^\s(\S+)\s$/) {
		872	my $s = $1;
		873	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
		874	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
		875	push @{ $self->{server} }, $ipn;
		876	} else {
840	push @{ $self->{search} }, $1;	877	push @{ $self->{search} }, $s;
841	$_ = <$fh>;
842	}	878	}
843	last;
844	}	879	}
845	}	880	}
846		881
847	while (<$fh>) {	882	# always add one fallback server
848	# second DNS.* is server address list	883	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		884
860	$self->_compile;	885	$self->_compile;
861	}	886	}
862	} else {	887	} else {
863	# try resolv.conf everywhere	888	# try resolv.conf everywhere
…		…
867	$self->parse_resolv_conf (<$fh>);	892	$self->parse_resolv_conf (<$fh>);
868	}	893	}
869	}	894	}
870	}	895	}
871		896
		897	=item $resolver->timeout ($timeout, ...)
		898
		899	Sets the timeout values. See the C<timeout> constructor argument (and note
		900	that this method uses the values itself, not an array-reference).
		901
		902	=cut
		903
		904	sub timeout {
		905	my ($self, @timeout) = @_;
		906
		907	$self->{timeout} = \@timeout;
		908	$self->_compile;
		909	}
		910
		911	=item $resolver->max_outstanding ($nrequests)
		912
		913	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		914	C<max_outstanding> constructor argument.
		915
		916	=cut
		917
		918	sub max_outstanding {
		919	my ($self, $max) = @_;
		920
		921	$self->{max_outstanding} = $max;
		922	$self->_scheduler;
		923	}
		924
872	sub _compile {	925	sub _compile {
873	my $self = shift;	926	my $self = shift;
		927
		928	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
		929	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
		930
		931	unless (@{ $self->{server} }) {
		932	# use 127.0.0.1 by default, and one opendns nameserver as fallback
		933	$self->{server} = [v127.0.0.1, $DNS_FALLBACK[rand @DNS_FALLBACK]];
		934	}
874		935
875	my @retry;	936	my @retry;
876		937
877	for my $timeout (@{ $self->{timeout} }) {	938	for my $timeout (@{ $self->{timeout} }) {
878	for my $server (@{ $self->{server} }) {	939	for my $server (@{ $self->{server} }) {
…		…
884	}	945	}
885		946
886	sub _feed {	947	sub _feed {
887	my ($self, $res) = @_;	948	my ($self, $res) = @_;
888		949
		950	($res) = $res =~ /^(.*)$/s
		951	if AnyEvent::TAINT && $self->{untaint};
		952
889	$res = dns_unpack $res	953	$res = dns_unpack $res
890	or return;	954	or return;
891		955
892	my $id = $self->{id}{$res->{id}};	956	my $id = $self->{id}{$res->{id}};
893		957
…		…
896	$NOW = time;	960	$NOW = time;
897	$id->[1]->($res);	961	$id->[1]->($res);
898	}	962	}
899		963
900	sub _recv {	964	sub _recv {
901	my ($self) = @_;	965	my ($self, $pkt, $peer) = @_;
902		966
903	while (my $peer = recv $self->{fh}, my $res, 4096, 0) {	967	# we ignore errors (often one gets port unreachable, but there is
		968	# no good way to take advantage of that.
		969
904	my ($port, $host) = Socket::unpack_sockaddr_in $peer;	970	my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer);
905		971
906	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };	972	return unless $port == 53 && grep $_ eq $host, @{ $self->{server} };
907		973
908	$self->_feed ($res);	974	$self->_feed ($pkt);
909	}
910	}	975	}
911		976
		977	sub _free_id {
		978	my ($self, $id, $timeout) = @_;
		979
		980	if ($timeout) {
		981	# we need to block the id for a while
		982	$self->{id}{$id} = 1;
		983	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id];
		984	} else {
		985	# we can quickly recycle the id
		986	delete $self->{id}{$id};
		987	}
		988
		989	--$self->{outstanding};
		990	$self->_scheduler;
		991	}
		992
		993	# execute a single request, involves sending it with timeouts to multiple servers
912	sub _exec {	994	sub _exec {
913	my ($self, $req, $retry) = @_;	995	my ($self, $req) = @_;
914		996
		997	my $retry; # of retries
		998	my $do_retry;
		999
		1000	$do_retry = sub {
915	if (my $retry_cfg = $self->{retry}[$retry]) {	1001	my $retry_cfg = $self->{retry}[$retry++]
		1002	or do {
		1003	# failure
		1004	$self->_free_id ($req->[2], $retry > 1);
		1005	undef $do_retry; return $req->[1]->();
		1006	};
		1007
916	my ($server, $timeout) = @$retry_cfg;	1008	my ($server, $timeout) = @$retry_cfg;
917		1009
918	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {	1010	$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub {
919	$NOW = time;	1011	$NOW = time;
920		1012
921	# timeout, try next	1013	# timeout, try next
922	$self->_exec ($req, $retry + 1);	1014	&$do_retry if $do_retry;
923	}), sub {	1015	}), sub {
924	my ($res) = @_;	1016	my ($res) = @_;
925		1017
926	if ($res->{tc}) {	1018	if ($res->{tc}) {
927	# success, but truncated, so use tcp	1019	# success, but truncated, so use tcp
928	AnyEvent::Socket::tcp_connect ((Socket::inet_ntoa $server), 53, sub {	1020	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1021	return unless $do_retry; # some other request could have invalidated us already
		1022
929	my ($fh) = @_	1023	my ($fh) = @_
930	or return $self->_exec ($req, $retry + 1);	1024	or return &$do_retry;
931		1025
932	my $handle = new AnyEvent::Handle	1026	my $handle; $handle = new AnyEvent::Handle
933	fh => $fh,	1027	fh => $fh,
		1028	timeout => $timeout,
934	on_error => sub {	1029	on_error => sub {
		1030	undef $handle;
		1031	return unless $do_retry; # some other request could have invalidated us already
935	# failure, try next	1032	# failure, try next
936	$self->_exec ($req, $retry + 1);	1033	&$do_retry;
937	};	1034	};
938		1035
939	$handle->push_write (pack "n/a", $req->[0]);	1036	$handle->push_write (pack "n/a", $req->[0]);
940	$handle->push_read_chunk (2, sub {	1037	$handle->push_read (chunk => 2, sub {
941	$handle->unshift_read_chunk ((unpack "n", $_[1]), sub {	1038	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1039	undef $handle;
942	$self->_feed ($_[1]);	1040	$self->_feed ($_[1]);
943	});	1041	});
944	});	1042	});
945	shutdown $fh, 1;
946		1043
947	}, sub { $timeout });	1044	}, sub { $timeout });
948		1045
949	} else {	1046	} else {
950	# success	1047	# success
951	$self->{id}{$req->[2]} = 1;	1048	$self->_free_id ($req->[2], $retry > 1);
952	push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $req->[2]];	1049	undef $do_retry; return $req->[1]->($res);
953	--$self->{outstanding};
954	$self->_scheduler;
955
956	$req->[1]->($res);
957	}	1050	}
958	}];	1051	}];
		1052
		1053	my $sa = AnyEvent::Socket::pack_sockaddr (DOMAIN_PORT, $server);
959		1054
960	send $self->{fh}, $req->[0], 0, Socket::pack_sockaddr_in 53, $server;	1055	my $fh = AF_INET == Socket::sockaddr_family ($sa)
961	} else {	1056	? $self->{fh4} : $self->{fh6}
962	# failure	1057	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		1058
968	$req->[1]->();	1059	send $fh, $req->[0], 0, $sa;
969	}	1060	};
		1061
		1062	&$do_retry;
970	}	1063	}
971		1064
972	sub _scheduler {	1065	sub _scheduler {
973	my ($self) = @_;	1066	my ($self) = @_;
		1067
		1068	no strict 'refs';
974		1069
975	$NOW = time;	1070	$NOW = time;
976		1071
977	# first clear id reuse queue	1072	# first clear id reuse queue
978	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1073	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
…		…
987	$self->_scheduler;	1082	$self->_scheduler;
988	});	1083	});
989	last;	1084	last;
990	}	1085	}
991		1086
992	my $req = shift @{ $self->{queue} }	1087	if (my $req = shift @{ $self->{queue} }) {
993	or last;	1088	# found a request in the queue, execute it
994
995	while () {	1089	while () {
996	$req->[2] = int rand 65536;	1090	$req->[2] = int rand 65536;
997	last unless exists $self->{id}{$req->[2]};	1091	last unless exists $self->{id}{$req->[2]};
		1092	}
		1093
		1094	++$self->{outstanding};
		1095	$self->{id}{$req->[2]} = 1;
		1096	substr $req->[0], 0, 2, pack "n", $req->[2];
		1097
		1098	$self->_exec ($req);
		1099
		1100	} elsif (my $cb = shift @{ $self->{wait} }) {
		1101	# found a wait_for_slot callback, call that one first
		1102	$cb->($self);
		1103
		1104	} else {
		1105	# nothing to do, just exit
		1106	last;
998	}	1107	}
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	}	1108	}
1006	}	1109	}
1007		1110
1008	=item $resolver->request ($req, $cb->($res))	1111	=item $resolver->request ($req, $cb->($res))
1009		1112
		1113	This is the main low-level workhorse for sending DNS requests.
		1114
1010	Sends a single request (a hash-ref formated as specified for	1115	This function sends a single request (a hash-ref formated as specified
1011	C<dns_pack>) to the configured nameservers including	1116	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1117	response. It handles timeouts, retries and automatically falls back to
		1118	virtual circuit mode (TCP) when it receives a truncated reply.
		1119
1012	retries. Calls the callback with the decoded response packet if a reply	1120	Calls the callback with the decoded response packet if a reply was
1013	was received, or no arguments on timeout.	1121	received, or no arguments in case none of the servers answered.
1014		1122
1015	=cut	1123	=cut
1016		1124
1017	sub request($$) {	1125	sub request($$) {
1018	my ($self, $req, $cb) = @_;	1126	my ($self, $req, $cb) = @_;
1019		1127
1020	push @{ $self->{queue} }, [dns_pack $req, $cb];	1128	push @{ $self->{queue} }, [dns_pack $req, $cb];
1021	$self->_scheduler;	1129	$self->_scheduler;
1022	}	1130	}
1023		1131
1024	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1132	=item $resolver->resolve ($qname, $qtype, %options, $cb->(@rr))
1025		1133
1026	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1134	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
1027	qtype of "*" is supported and means "any").	1135
		1136	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1137	a lowercase name (you have to look at the source to see which aliases are
		1138	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1139	more are known to this module). A C<$qtype> of "*" is supported and means
		1140	"any" record type.
1028		1141
1029	The callback will be invoked with a list of matching result records or	1142	The callback will be invoked with a list of matching result records or
1030	none on any error or if the name could not be found.	1143	none on any error or if the name could not be found.
1031		1144
1032	CNAME chains (although illegal) are followed up to a length of 8.	1145	CNAME chains (although illegal) are followed up to a length of 10.
1033		1146
		1147	The callback will be invoked with arraryefs of the form C<[$name, $type,
		1148	$class, @data>], where C<$name> is the domain name, C<$type> a type string
		1149	or number, C<$class> a class name and @data is resource-record-dependent
		1150	data. For C<a> records, this will be the textual IPv4 addresses, for C<ns>
		1151	or C<cname> records this will be a domain name, for C<txt> records these
		1152	are all the strings and so on.
		1153
		1154	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1155	decoded. All resource records not known to this module will have
		1156	the raw C<rdata> field as fourth entry.
		1157
1034	Note that this resolver is just a stub resolver: it requires a nameserver	1158	Note that this resolver is just a stub resolver: it requires a name server
1035	supporting recursive queries, will not do any recursive queries itself and	1159	supporting recursive queries, will not do any recursive queries itself and
1036	is not secure when used against an untrusted name server.	1160	is not secure when used against an untrusted name server.
1037		1161
1038	The following options are supported:	1162	The following options are supported:
1039		1163
…		…
1041		1165
1042	=item search => [$suffix...]	1166	=item search => [$suffix...]
1043		1167
1044	Use the given search list (which might be empty), by appending each one	1168	Use the given search list (which might be empty), by appending each one
1045	in turn to the C<$qname>. If this option is missing then the configured	1169	in turn to the C<$qname>. If this option is missing then the configured
1046	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1170	C<ndots> and C<search> values define its value (depending on C<ndots>, the
1047	then the searchlist will be ignored.	1171	empty suffix will be prepended or appended to that C<search> value). If
		1172	the C<$qname> ends in a dot, then the searchlist will be ignored.
1048		1173
1049	=item accept => [$type...]	1174	=item accept => [$type...]
1050		1175
1051	Lists the acceptable result types: only result types in this set will be	1176	Lists the acceptable result types: only result types in this set will be
1052	accepted and returned. The default includes the C<$qtype> and nothing	1177	accepted and returned. The default includes the C<$qtype> and nothing
1053	else.	1178	else. If this list includes C<cname>, then CNAME-chains will not be
		1179	followed (because you asked for the CNAME record).
1054		1180
1055	=item class => "class"	1181	=item class => "class"
1056		1182
1057	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1183	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
1058	hesiod are the only ones making sense). The default is "in", of course.	1184	hesiod are the only ones making sense). The default is "in", of course.
1059		1185
1060	=back	1186	=back
1061		1187
1062	Examples:	1188	Examples:
1063		1189
1064	$res->resolve ("ruth.plan9.de", "a", sub {	1190	# full example, you can paste this into perl:
1065	warn Dumper [@_];	1191	use Data::Dumper;
1066	});	1192	use AnyEvent::DNS;
		1193	AnyEvent::DNS::resolver->resolve (
		1194	"google.com", "*", my $cv = AnyEvent->condvar);
		1195	warn Dumper [$cv->recv];
1067		1196
		1197	# shortened result:
1068	[	1198	# [
		1199	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1200	# 2008052701, 7200, 1800, 1209600, 300 ],
1069	[	1201	# [
1070	'ruth.schmorp.de',	1202	# 'google.com', 'txt', 'in',
1071	'a',	1203	# 'v=spf1 include:_netblocks.google.com ~all'
1072	'in',	1204	# ],
1073	'129.13.162.95'	1205	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1206	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1207	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
1074	]	1208	# ]
		1209
		1210	# resolve a records:
		1211	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1212
		1213	# result:
		1214	# [
		1215	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
1075	]	1216	# ]
1076		1217
		1218	# resolve any records, but return only a and aaaa records:
1077	$res->resolve ("test1.laendle", "*",	1219	$res->resolve ("test1.laendle", "*",
1078	accept => ["a", "aaaa"],	1220	accept => ["a", "aaaa"],
1079	sub {	1221	sub {
1080	warn Dumper [@_];	1222	warn Dumper [@_];
1081	}	1223	}
1082	);	1224	);
1083		1225
1084	[	1226	# result:
1085	[	1227	# [
1086	'test1.laendle',	1228	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
1087	'a',	1229	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
1088	'in',
1089	'10.0.0.255'
1090	],
1091	[
1092	'test1.laendle',
1093	'aaaa',
1094	'in',
1095	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
1096	]	1230	# ]
1097	]
1098		1231
1099	=cut	1232	=cut
1100		1233
1101	sub resolve($%) {	1234	sub resolve($%) {
1102	my $cb = pop;	1235	my $cb = pop;
…		…
1115	my %atype = $opt{accept}	1248	my %atype = $opt{accept}
1116	? map +($_ => 1), @{ $opt{accept} }	1249	? map +($_ => 1), @{ $opt{accept} }
1117	: ($qtype => 1);	1250	: ($qtype => 1);
1118		1251
1119	# advance in searchlist	1252	# advance in searchlist
1120	my $do_search; $do_search = sub {	1253	my ($do_search, $do_req);
		1254
		1255	$do_search = sub {
1121	@search	1256	@search
1122	or return $cb->();	1257	or (undef $do_search), (undef $do_req), return $cb->();
1123		1258
1124	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1259	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
1125	my $depth = 2;	1260	my $depth = 10;
1126		1261
1127	# advance in cname-chain	1262	# advance in cname-chain
1128	my $do_req; $do_req = sub {	1263	$do_req = sub {
1129	$self->request ({	1264	$self->request ({
1130	rd => 1,	1265	rd => 1,
1131	qd => [[$name, $qtype, $class]],	1266	qd => [[$name, $qtype, $class]],
1132	}, sub {	1267	}, sub {
1133	my ($res) = @_	1268	my ($res) = @_
…		…
1137		1272
1138	while () {	1273	while () {
1139	# results found?	1274	# results found?
1140	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };	1275	my @rr = grep $name eq lc $_->[0] && ($atype{"*"} \|\| $atype{$_->[1]}), @{ $res->{an} };
1141		1276
1142	return $cb->(@rr)	1277	(undef $do_search), (undef $do_req), return $cb->(@rr)
1143	if @rr;	1278	if @rr;
1144		1279
1145	# see if there is a cname we can follow	1280	# see if there is a cname we can follow
1146	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };	1281	my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} };
1147		1282
…		…
1168	};	1303	};
1169		1304
1170	$do_search->();	1305	$do_search->();
1171	}	1306	}
1172		1307
		1308	=item $resolver->wait_for_slot ($cb->($resolver))
		1309
		1310	Wait until a free request slot is available and call the callback with the
		1311	resolver object.
		1312
		1313	A request slot is used each time a request is actually sent to the
		1314	nameservers: There are never more than C<max_outstanding> of them.
		1315
		1316	Although you can submit more requests (they will simply be queued until
		1317	a request slot becomes available), sometimes, usually for rate-limiting
		1318	purposes, it is useful to instead wait for a slot before generating the
		1319	request (or simply to know when the request load is low enough so one can
		1320	submit requests again).
		1321
		1322	This is what this method does: The callback will be called when submitting
		1323	a DNS request will not result in that request being queued. The callback
		1324	may or may not generate any requests in response.
		1325
		1326	Note that the callback will only be invoked when the request queue is
		1327	empty, so this does not play well if somebody else keeps the request queue
		1328	full at all times.
		1329
		1330	=cut
		1331
		1332	sub wait_for_slot {
		1333	my ($self, $cb) = @_;
		1334
		1335	push @{ $self->{wait} }, $cb;
		1336	$self->_scheduler;
		1337	}
		1338
1173	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end	1339	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
1174		1340
1175	1;	1341	1;
1176		1342
1177	=back	1343	=back
1178		1344
1179	=head1 AUTHOR	1345	=head1 AUTHOR
1180		1346
1181	Marc Lehmann <schmorp@schmorp.de>	1347	Marc Lehmann <schmorp@schmorp.de>
1182	http://home.schmorp.de/	1348	http://home.schmorp.de/
1183		1349
1184	=cut	1350	=cut
1185		1351

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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 1.95 by root, Fri Jun 26 06:33:17 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 1.95 by root, Fri Jun 26 06:33:17 2009 UTC