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

Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.42 by root, Thu May 29 06:17:52 2008 UTC vs.
Revision 1.65 by root, Thu Jun 5 18:30:08 2008 UTC

…		…
2		2
3	AnyEvent::DNS - fully asynchronous DNS resolution	3	AnyEvent::DNS - fully asynchronous DNS resolution
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::DNS;	7	use AnyEvent::DNS;
8		8
9	my $cv = AnyEvent->condvar;	9	my $cv = AnyEvent->condvar;
10	AnyEvent::DNS::a "www.google.de", $cv;	10	AnyEvent::DNS::a "www.google.de", $cv;
11	# ... later	11	# ... later
12	my @addrs = $cv->recv;	12	my @addrs = $cv->recv;
13		13
14	=head1 DESCRIPTION	14	=head1 DESCRIPTION
15		15
16	This module offers both a number of DNS convenience functions as well	16	This module offers both a number of DNS convenience functions as well
17	as a fully asynchronous and high-performance pure-perl stub resolver.	17	as a fully asynchronous and high-performance pure-perl stub resolver.
18		18
19	The stub resolver supports DNS over UDP, optional EDNS0 support for up to	19	The stub resolver supports DNS over IPv4 and IPv6, UDP and TCP, optional
20	4kiB datagrams and automatically falls back to virtual circuit mode for	20	EDNS0 support for up to 4kiB datagrams and automatically falls back to
21	large responses.	21	virtual circuit mode for large responses.
22		22
23	=head2 CONVENIENCE FUNCTIONS	23	=head2 CONVENIENCE FUNCTIONS
24		24
25	=over 4	25	=over 4
26		26
…		…
35		35
36	use AnyEvent ();	36	use AnyEvent ();
37	use AnyEvent::Handle ();	37	use AnyEvent::Handle ();
38	use AnyEvent::Util qw(AF_INET6);	38	use AnyEvent::Util qw(AF_INET6);
39		39
40	our $VERSION = '1.0';	40	our $VERSION = 4.14;
41		41
42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);	42	our @DNS_FALLBACK = (v208.67.220.220, v208.67.222.222);
43		43
44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)	44	=item AnyEvent::DNS::a $domain, $cb->(@addrs)
45		45
…		…
65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)	65	=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr)
66		66
67	Tries to resolve the given service, protocol and domain name into a list	67	Tries to resolve the given service, protocol and domain name into a list
68	of service records.	68	of service records.
69		69
70	Each srv_rr is an array reference with the following contents:	70	Each C<$srv_rr> is an array reference with the following contents:
71	C<[$priority, $weight, $transport, $target]>.	71	C<[$priority, $weight, $transport, $target]>.
72		72
73	They will be sorted with lowest priority, highest weight first (TODO:	73	They will be sorted with lowest priority first, then randomly
74	should use the RFC algorithm to reorder same-priority records for weight).	74	distributed by weight as per RFC 2782.
75		75
76	Example:	76	Example:
77		77
78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...	78	AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ...
79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )	79	# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] )
80		80
81	=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)
82		93
83	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)
84	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.
85		108
86	Example:	109	Example:
87		110
88	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };	111	AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift };
89	# => f.root-servers.net	112	# => f.root-servers.net
90
91	=item AnyEvent::DNS::any $domain, $cb->(@rrs)
92
93	Tries to resolve the given domain and passes all resource records found to
94	the callback.
95		113
96	=cut	114	=cut
97		115
98	sub MAX_PKT() { 4096 } # max packet size we advertise and accept	116	sub MAX_PKT() { 4096 } # max packet size we advertise and accept
99		117
…		…
144	sub srv($$$$) {	162	sub srv($$$$) {
145	my ($service, $proto, $domain, $cb) = @_;	163	my ($service, $proto, $domain, $cb) = @_;
146		164
147	# todo, ask for any and check glue records	165	# todo, ask for any and check glue records
148	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {	166	resolver->resolve ("_$service._$proto.$domain" => "srv", sub {
149	$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] \|\| $b->[4] <=> $a->[4] } @_);	167	my @res;
		168
		169	# classify by priority
		170	my %pri;
		171	push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ]
		172	for @_;
		173
		174	# order by priority
		175	for my $pri (sort { $a <=> $b } keys %pri) {
		176	# order by weight
		177	my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} };
		178
		179	my $sum; $sum += $_->[1] for @rr;
		180
		181	while (@rr) {
		182	my $w = int rand $sum + 1;
		183	for (0 .. $#rr) {
		184	if (($w -= $rr[$_][1]) <= 0) {
		185	$sum -= $rr[$_][1];
		186	push @res, splice @rr, $_, 1, ();
		187	last;
		188	}
		189	}
		190	}
		191	}
		192
		193	$cb->(@res);
150	});	194	});
151	}	195	}
152		196
153	sub ptr($$) {	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($$) {
154	my ($ip, $cb) = @_;	239	my ($ip, $cb) = @_;
155		240
156	$ip = AnyEvent::Socket::parse_address ($ip)	241	$ip = _munge_ptr AnyEvent::Socket::parse_address ($ip)
157	or return $cb->();	242	or return $cb->();
158
159	my $af = AnyEvent::Socket::address_family ($ip);
160
161	if ($af == AF_INET) {
162	$ip = join ".", (reverse split /\./, $ip), "in-addr.arpa.";
163	} elsif ($af == AF_INET6) {
164	$ip = join ".", (reverse split //, unpack "H*", $ip), "ip6.arpa.";
165	} else {
166	return $cb->();
167	}
168		243
169	resolver->resolve ($ip => "ptr", sub {	244	resolver->resolve ($ip => "ptr", sub {
170	$cb->(map $_->[3], @_);	245	$cb->(map $_->[3], @_);
171	});	246	});
172	}	247	}
173		248
174	sub any($$) {	249	sub reverse_verify($$) {
175	my ($domain, $cb) = @_;	250	my ($ip, $cb) = @_;
		251
		252	my $ipn = AnyEvent::Socket::parse_address ($ip)
		253	or return $cb->();
176		254
177	resolver->resolve ($domain => "*", $cb);	255	my $af = AnyEvent::Socket::address_family ($ipn);
		256
		257	my @res;
		258	my $cnt;
		259
		260	my $ptr = _munge_ptr $ipn
		261	or return $cb->();
		262
		263	$ip = AnyEvent::Socket::format_address ($ipn); # normalise into the same form
		264
		265	ptr $ptr, sub {
		266	for my $name (@_) {
		267	++$cnt;
		268
		269	# () around AF_INET to work around bug in 5.8
		270	resolver->resolve ("$name." => ($af == (AF_INET) ? "a" : "aaaa"), sub {
		271	for (@_) {
		272	push @res, $name
		273	if $_->[3] eq $ip;
		274	}
		275	$cb->(@res) unless --$cnt;
		276	});
		277	}
		278
		279	$cb->() unless $cnt;
		280	};
178	}	281	}
179		282
180	#################################################################################	283	#################################################################################
181		284
182	=back	285	=back
…		…
248	minfo => 14,	351	minfo => 14,
249	mx => 15,	352	mx => 15,
250	txt => 16,	353	txt => 16,
251	aaaa => 28,	354	aaaa => 28,
252	srv => 33,	355	srv => 33,
		356	naptr => 35, # rfc2915
253	opt => 41,	357	opt => 41,
254	spf => 99,	358	spf => 99,
255	tkey => 249,	359	tkey => 249,
256	tsig => 250,	360	tsig => 250,
257	ixfr => 251,	361	ixfr => 251,
…		…
270	"*" => 255,	374	"*" => 255,
271	);	375	);
272		376
273	our %class_str = reverse %class_id;	377	our %class_str = reverse %class_id;
274		378
275	# names MUST have a trailing dot
276	sub _enc_name($) {	379	sub _enc_name($) {
277	pack "(C/a)", (split /\./, shift), ""	380	pack "(C/a)", (split /\./, shift), ""
278	}	381	}
279		382
280	sub _enc_qd() {	383	sub _enc_qd() {
…		…
287	die "encoding of resource records is not supported";	390	die "encoding of resource records is not supported";
288	}	391	}
289		392
290	=item $pkt = AnyEvent::DNS::dns_pack $dns	393	=item $pkt = AnyEvent::DNS::dns_pack $dns
291		394
292	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
293	recommended, then everything will be totally clear. Or maybe not.	396	recommended, then everything will be totally clear. Or maybe not.
294		397
295	Resource records are not yet encodable.	398	Resource records are not yet encodable.
296		399
297	Examples:	400	Examples:
298		401
299	# very simple request, using lots of default values:	402	# very simple request, using lots of default values:
300	{ rd => 1, qd => [ [ "host.domain", "a"] ] }	403	{ rd => 1, qd => [ [ "host.domain", "a"] ] }
301		404
302	# more complex example, showing how flags etc. are named:	405	# more complex example, showing how flags etc. are named:
303		406
304	{	407	{
305	id => 10000,	408	id => 10000,
306	op => "query",	409	op => "query",
307	rc => "nxdomain",	410	rc => "nxdomain",
308		411
309	# flags	412	# flags
310	qr => 1,	413	qr => 1,
311	aa => 0,	414	aa => 0,
312	tc => 0,	415	tc => 0,
313	rd => 0,	416	rd => 0,
314	ra => 0,	417	ra => 0,
315	ad => 0,	418	ad => 0,
316	cd => 0,	419	cd => 0,
317		420
318	qd => [@rr], # query section	421	qd => [@rr], # query section
319	an => [@rr], # answer section	422	an => [@rr], # answer section
320	ns => [@rr], # authority section	423	ns => [@rr], # authority section
321	ar => [@rr], # additional records section	424	ar => [@rr], # additional records section
322	}	425	}
323		426
324	=cut	427	=cut
325		428
326	sub dns_pack($) {	429	sub dns_pack($) {
327	my ($req) = @_;	430	my ($req) = @_;
…		…
340	+ $rcode_id{$req->{rc}} * 0x0001,	443	+ $rcode_id{$req->{rc}} * 0x0001,
341		444
342	scalar @{ $req->{qd} \|\| [] },	445	scalar @{ $req->{qd} \|\| [] },
343	scalar @{ $req->{an} \|\| [] },	446	scalar @{ $req->{an} \|\| [] },
344	scalar @{ $req->{ns} \|\| [] },	447	scalar @{ $req->{ns} \|\| [] },
345	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # include EDNS0 option here	448	$EDNS0 + scalar @{ $req->{ar} \|\| [] }, # EDNS0 option included here
346		449
347	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),	450	(join "", map _enc_qd, @{ $req->{qd} \|\| [] }),
348	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),	451	(join "", map _enc_rr, @{ $req->{an} \|\| [] }),
349	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),	452	(join "", map _enc_rr, @{ $req->{ns} \|\| [] }),
350	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),	453	(join "", map _enc_rr, @{ $req->{ar} \|\| [] }),
351		454
352	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0, 4kiB udp payload size	455	($EDNS0 ? pack "C nnNn", 0, 41, MAX_PKT, 0, 0 : "") # EDNS0 option
353	}	456	}
354		457
355	our $ofs;	458	our $ofs;
356	our $pkt;	459	our $pkt;
357		460
…		…
402	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo	505	13 => sub { unpack "C/a* C/a*", $_ }, # hinfo
403	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx	506	15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_name) }, # mx
404	16 => sub { unpack "(C/a)", $_ }, # txt	507	16 => sub { unpack "(C/a)", $_ }, # txt
405	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa	508	28 => sub { AnyEvent::Socket::format_address ($_) }, # aaaa
406	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv	509	33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_name) }, # srv
		510	35 => sub { # naptr
		511	my ($order, $preference, $flags, $service, $regexp, $offset) = unpack "nn C/a* C/a* C/a* .", $_;
		512	local $ofs = $ofs + $offset - length;
		513	($order, $preference, $flags, $service, $regexp, _dec_name)
		514	},
407	99 => sub { unpack "(C/a)", $_ }, # spf	515	99 => sub { unpack "(C/a)", $_ }, # spf
408	);	516	);
409		517
410	sub _dec_rr {	518	sub _dec_rr {
411	my $name = _dec_name;	519	my $name = _dec_name;
…		…
425		533
426	Unpacks a DNS packet into a perl data structure.	534	Unpacks a DNS packet into a perl data structure.
427		535
428	Examples:	536	Examples:
429		537
430	# an unsuccessful reply	538	# an unsuccessful reply
431	{	539	{
432	'qd' => [	540	'qd' => [
433	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]	541	[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ]
434	],	542	],
435	'rc' => 'nxdomain',	543	'rc' => 'nxdomain',
436	'ar' => [],	544	'ar' => [],
437	'ns' => [	545	'ns' => [
438	[	546	[
439	'uni-karlsruhe.de',	547	'uni-karlsruhe.de',
440	'soa',	548	'soa',
441	'in',	549	'in',
442	'netserv.rz.uni-karlsruhe.de',	550	'netserv.rz.uni-karlsruhe.de',
443	'hostmaster.rz.uni-karlsruhe.de',	551	'hostmaster.rz.uni-karlsruhe.de',
444	2008052201, 10800, 1800, 2592000, 86400	552	2008052201, 10800, 1800, 2592000, 86400
445	]	553	]
446	],	554	],
447	'tc' => '',	555	'tc' => '',
448	'ra' => 1,	556	'ra' => 1,
449	'qr' => 1,	557	'qr' => 1,
450	'id' => 45915,	558	'id' => 45915,
451	'aa' => '',	559	'aa' => '',
452	'an' => [],	560	'an' => [],
453	'rd' => 1,	561	'rd' => 1,
454	'op' => 'query'	562	'op' => 'query'
455	}	563	}
456		564
457	# a successful reply	565	# a successful reply
458		566
459	{	567	{
460	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],	568	'qd' => [ [ 'www.google.de', 'a', 'in' ] ],
461	'rc' => 0,	569	'rc' => 0,
462	'ar' => [	570	'ar' => [
463	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],	571	[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ],
464	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],	572	[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ],
465	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],	573	[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ],
466	],	574	],
467	'ns' => [	575	'ns' => [
468	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],	576	[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ],
469	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],	577	[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ],
470	],	578	],
471	'tc' => '',	579	'tc' => '',
472	'ra' => 1,	580	'ra' => 1,
473	'qr' => 1,	581	'qr' => 1,
474	'id' => 64265,	582	'id' => 64265,
475	'aa' => '',	583	'aa' => '',
476	'an' => [	584	'an' => [
477	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],	585	[ 'www.google.de', 'cname', 'in', 'www.google.com' ],
478	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],	586	[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ],
479	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],	587	[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ],
480	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],	588	[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ],
481	],	589	],
482	'rd' => 1,	590	'rd' => 1,
483	'op' => 0	591	'op' => 0
484	}	592	}
485		593
486	=cut	594	=cut
487		595
488	sub dns_unpack($) {	596	sub dns_unpack($) {
489	local $pkt = shift;	597	local $pkt = shift;
…		…
581	The number of dots (default: C<1>) that a name must have so that the resolver	689	The number of dots (default: C<1>) that a name must have so that the resolver
582	tries to resolve the name without any suffixes first.	690	tries to resolve the name without any suffixes first.
583		691
584	=item max_outstanding => $integer	692	=item max_outstanding => $integer
585		693
586	Most name servers do not handle many parallel requests very well. This option	694	Most name servers do not handle many parallel requests very well. This
587	limits the number of outstanding requests to C<$n> (default: C<10>), that means	695	option limits the number of outstanding requests to C<$integer>
588	if you request more than this many requests, then the additional requests will be queued	696	(default: C<10>), that means if you request more than this many requests,
589	until some other requests have been resolved.	697	then the additional requests will be queued until some other requests have
		698	been resolved.
590		699
591	=item reuse => $seconds	700	=item reuse => $seconds
592		701
593	The number of seconds (default: C<300>) that a query id cannot be re-used	702	The number of seconds (default: C<300>) that a query id cannot be re-used
594	after a timeout. If there as no time-out then query id's can be reused	703	after a timeout. If there was no time-out then query ids can be reused
595	immediately.	704	immediately.
596		705
597	=back	706	=back
598		707
599	=cut	708	=cut
600		709
601	sub new {	710	sub new {
602	my ($class, %arg) = @_;	711	my ($class, %arg) = @_;
603
604	# try to create a ipv4 and an ipv6 socket
605	# only fail when we cnanot create either
606
607	socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0;
608	socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0;
609
610	$fh4 \|\| $fh6
611	or Carp::croak "unable to create either an IPv6 or an IPv4 socket";
612		712
613	my $self = bless {	713	my $self = bless {
614	server => [],	714	server => [],
615	timeout => [2, 5, 5],	715	timeout => [2, 5, 5],
616	search => [],	716	search => [],
617	ndots => 1,	717	ndots => 1,
618	max_outstanding => 10,	718	max_outstanding => 10,
619	reuse => 300, # reuse id's after 5 minutes only, if possible	719	reuse => 300,
620	%arg,	720	%arg,
621	reuse_q => [],	721	reuse_q => [],
622	}, $class;	722	}, $class;
623		723
624	# search should default to gethostname's domain	724	# search should default to gethostname's domain
625	# but perl lacks a good posix module	725	# but perl lacks a good posix module
626		726
		727	# try to create an ipv4 and an ipv6 socket
		728	# only fail when we cannot create either
		729	my $got_socket;
		730
627	Scalar::Util::weaken (my $wself = $self);	731	Scalar::Util::weaken (my $wself = $self);
628		732
629	if ($fh4) {	733	if (socket my $fh4, AF_INET , &Socket::SOCK_DGRAM, 0) {
		734	++$got_socket;
		735
630	AnyEvent::Util::fh_nonblocking $fh4, 1;	736	AnyEvent::Util::fh_nonblocking $fh4, 1;
631	$self->{fh4} = $fh4;	737	$self->{fh4} = $fh4;
632	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {	738	$self->{rw4} = AnyEvent->io (fh => $fh4, poll => "r", cb => sub {
633	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {	739	if (my $peer = recv $fh4, my $pkt, MAX_PKT, 0) {
634	$wself->_recv ($pkt, $peer);	740	$wself->_recv ($pkt, $peer);
635	}	741	}
636	});	742	});
637	}	743	}
638		744
639	if ($fh6) {	745	if (AF_INET6 && socket my $fh6, AF_INET6, &Socket::SOCK_DGRAM, 0) {
		746	++$got_socket;
		747
640	$self->{fh6} = $fh6;	748	$self->{fh6} = $fh6;
641	AnyEvent::Util::fh_nonblocking $fh6, 1;	749	AnyEvent::Util::fh_nonblocking $fh6, 1;
642	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {	750	$self->{rw6} = AnyEvent->io (fh => $fh6, poll => "r", cb => sub {
643	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {	751	if (my $peer = recv $fh6, my $pkt, MAX_PKT, 0) {
644	$wself->_recv ($pkt, $peer);	752	$wself->_recv ($pkt, $peer);
645	}	753	}
646	});	754	});
647	}	755	}
		756
		757	$got_socket
		758	or Carp::croak "unable to create either an IPv4 or an IPv6 socket";
648		759
649	$self->_compile;	760	$self->_compile;
650		761
651	$self	762	$self
652	}	763	}
…		…
729	# - the registry thing needs separate code on win32 native vs. cygwin	840	# - the registry thing needs separate code on win32 native vs. cygwin
730	# - the registry layout differs between windows versions	841	# - the registry layout differs between windows versions
731	# - calling windows api functions doesn't work on cygwin	842	# - calling windows api functions doesn't work on cygwin
732	# - ipconfig uses locale-specific messages	843	# - ipconfig uses locale-specific messages
733		844
734	# we use ipconfig parsing because, despite all it's brokenness,	845	# we use ipconfig parsing because, despite all its brokenness,
735	# it seems most stable in practise.	846	# it seems most stable in practise.
736	# for good measure, we append a fallback nameserver to our list.	847	# for good measure, we append a fallback nameserver to our list.
737		848
738	if (open my $fh, "ipconfig /all \|") {	849	if (open my $fh, "ipconfig /all \|") {
739	# parsing strategy: we go through the output and look for	850	# parsing strategy: we go through the output and look for
…		…
748	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {	859	} elsif (/^\S/ \|\| /^\s[^:]{16,}: /) {
749	$dns = 0;	860	$dns = 0;
750	}	861	}
751	if ($dns && /^\s(\S+)\s$/) {	862	if ($dns && /^\s(\S+)\s$/) {
752	my $s = $1;	863	my $s = $1;
753	$s =~ s/%\d+(?!\S)//; # get rid of scope id	864	$s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id
754	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {	865	if (my $ipn = AnyEvent::Socket::parse_address ($s)) {
755	push @{ $self->{server} }, $ipn;	866	push @{ $self->{server} }, $ipn;
756	} else {	867	} else {
757	push @{ $self->{search} }, $s;	868	push @{ $self->{search} }, $s;
758	}	869	}
…		…
772	$self->parse_resolv_conf (<$fh>);	883	$self->parse_resolv_conf (<$fh>);
773	}	884	}
774	}	885	}
775	}	886	}
776		887
		888	=item $resolver->timeout ($timeout, ...)
		889
		890	Sets the timeout values. See the C<timeout> constructor argument (and note
		891	that this method uses the values itself, not an array-reference).
		892
		893	=cut
		894
		895	sub timeout {
		896	my ($self, @timeout) = @_;
		897
		898	$self->{timeout} = \@timeout;
		899	$self->_compile;
		900	}
		901
		902	=item $resolver->max_outstanding ($nrequests)
		903
		904	Sets the maximum number of outstanding requests to C<$nrequests>. See the
		905	C<max_outstanding> constructor argument.
		906
		907	=cut
		908
		909	sub max_outstanding {
		910	my ($self, $max) = @_;
		911
		912	$self->{max_outstanding} = $max;
		913	$self->_scheduler;
		914	}
		915
777	sub _compile {	916	sub _compile {
778	my $self = shift;	917	my $self = shift;
779		918
780	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];	919	my %search; $self->{search} = [grep 0 < length, grep !$search{$_}++, @{ $self->{search} }];
781	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];	920	my %server; $self->{server} = [grep 0 < length, grep !$server{$_}++, @{ $self->{server} }];
…		…
865	my ($res) = @_;	1004	my ($res) = @_;
866		1005
867	if ($res->{tc}) {	1006	if ($res->{tc}) {
868	# success, but truncated, so use tcp	1007	# success, but truncated, so use tcp
869	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {	1008	AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub {
		1009	return unless $do_retry; # some other request could have invalidated us already
		1010
870	my ($fh) = @_	1011	my ($fh) = @_
871	or return &$do_retry;	1012	or return &$do_retry;
872		1013
873	my $handle = new AnyEvent::Handle	1014	my $handle; $handle = new AnyEvent::Handle
874	fh => $fh,	1015	fh => $fh,
		1016	timeout => $timeout,
875	on_error => sub {	1017	on_error => sub {
		1018	undef $handle;
		1019	return unless $do_retry; # some other request could have invalidated us already
876	# failure, try next	1020	# failure, try next
877	&$do_retry;	1021	&$do_retry;
878	};	1022	};
879		1023
880	$handle->push_write (pack "n/a", $req->[0]);	1024	$handle->push_write (pack "n/a", $req->[0]);
881	$handle->push_read (chunk => 2, sub {	1025	$handle->push_read (chunk => 2, sub {
882	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {	1026	$handle->unshift_read (chunk => (unpack "n", $_[1]), sub {
		1027	undef $handle;
883	$self->_feed ($_[1]);	1028	$self->_feed ($_[1]);
884	});	1029	});
885	});	1030	});
886	shutdown $fh, 1;
887		1031
888	}, sub { $timeout });	1032	}, sub { $timeout });
889		1033
890	} else {	1034	} else {
891	# success	1035	# success
…		…
907	}	1051	}
908		1052
909	sub _scheduler {	1053	sub _scheduler {
910	my ($self) = @_;	1054	my ($self) = @_;
911		1055
		1056	no strict 'refs';
		1057
912	$NOW = time;	1058	$NOW = time;
913		1059
914	# first clear id reuse queue	1060	# first clear id reuse queue
915	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }	1061	delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] }
916	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;	1062	while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW;
…		…
924	$self->_scheduler;	1070	$self->_scheduler;
925	});	1071	});
926	last;	1072	last;
927	}	1073	}
928		1074
929	my $req = shift @{ $self->{queue} }	1075	if (my $req = shift @{ $self->{queue} }) {
930	or last;	1076	# found a request in the queue, execute it
931
932	while () {	1077	while () {
933	$req->[2] = int rand 65536;	1078	$req->[2] = int rand 65536;
934	last unless exists $self->{id}{$req->[2]};	1079	last unless exists $self->{id}{$req->[2]};
		1080	}
		1081
		1082	++$self->{outstanding};
		1083	$self->{id}{$req->[2]} = 1;
		1084	substr $req->[0], 0, 2, pack "n", $req->[2];
		1085
		1086	$self->_exec ($req);
		1087
		1088	} elsif (my $cb = shift @{ $self->{wait} }) {
		1089	# found a wait_for_slot callback, call that one first
		1090	$cb->($self);
		1091
		1092	} else {
		1093	# nothing to do, just exit
		1094	last;
935	}	1095	}
936
937	++$self->{outstanding};
938	$self->{id}{$req->[2]} = 1;
939	substr $req->[0], 0, 2, pack "n", $req->[2];
940
941	$self->_exec ($req);
942	}	1096	}
943	}	1097	}
944		1098
945	=item $resolver->request ($req, $cb->($res))	1099	=item $resolver->request ($req, $cb->($res))
946		1100
		1101	This is the main low-level workhorse for sending DNS requests.
		1102
947	Sends a single request (a hash-ref formated as specified for	1103	This function sends a single request (a hash-ref formated as specified
948	C<dns_pack>) to the configured nameservers including	1104	for C<dns_pack>) to the configured nameservers in turn until it gets a
		1105	response. It handles timeouts, retries and automatically falls back to
		1106	virtual circuit mode (TCP) when it receives a truncated reply.
		1107
949	retries. Calls the callback with the decoded response packet if a reply	1108	Calls the callback with the decoded response packet if a reply was
950	was received, or no arguments on timeout.	1109	received, or no arguments in case none of the servers answered.
951		1110
952	=cut	1111	=cut
953		1112
954	sub request($$) {	1113	sub request($$) {
955	my ($self, $req, $cb) = @_;	1114	my ($self, $req, $cb) = @_;
…		…
958	$self->_scheduler;	1117	$self->_scheduler;
959	}	1118	}
960		1119
961	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))	1120	=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr))
962		1121
963	Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a	1122	Queries the DNS for the given domain name C<$qname> of type C<$qtype>.
964	qtype of "*" is supported and means "any").	1123
		1124	A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or
		1125	a lowercase name (you have to look at the source to see which aliases are
		1126	supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few
		1127	more are known to this module). A C<$qtype> of "*" is supported and means
		1128	"any" record type.
965		1129
966	The callback will be invoked with a list of matching result records or	1130	The callback will be invoked with a list of matching result records or
967	none on any error or if the name could not be found.	1131	none on any error or if the name could not be found.
968		1132
969	CNAME chains (although illegal) are followed up to a length of 8.	1133	CNAME chains (although illegal) are followed up to a length of 10.
		1134
		1135	The callback will be invoked with an result code in string form (noerror,
		1136	formerr, servfail, nxdomain, notimp, refused and so on), or numerical
		1137	form if the result code is not supported. The remaining arguments are
		1138	arraryefs of the form C<[$name, $type, $class, @data>], where C<$name> is
		1139	the domain name, C<$type> a type string or number, C<$class> a class name
		1140	and @data is resource-record-dependent data. For C<a> records, this will
		1141	be the textual IPv4 addresses, for C<ns> or C<cname> records this will be
		1142	a domain name, for C<txt> records these are all the strings and so on.
		1143
		1144	All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are
		1145	decoded. All resource records not known to this module will have
		1146	the raw C<rdata> field as fourth entry.
970		1147
971	Note that this resolver is just a stub resolver: it requires a name server	1148	Note that this resolver is just a stub resolver: it requires a name server
972	supporting recursive queries, will not do any recursive queries itself and	1149	supporting recursive queries, will not do any recursive queries itself and
973	is not secure when used against an untrusted name server.	1150	is not secure when used against an untrusted name server.
974		1151
…		…
978		1155
979	=item search => [$suffix...]	1156	=item search => [$suffix...]
980		1157
981	Use the given search list (which might be empty), by appending each one	1158	Use the given search list (which might be empty), by appending each one
982	in turn to the C<$qname>. If this option is missing then the configured	1159	in turn to the C<$qname>. If this option is missing then the configured
983	C<ndots> and C<search> define its value. If the C<$qname> ends in a dot,	1160	C<ndots> and C<search> values define its value (depending on C<ndots>, the
984	then the searchlist will be ignored.	1161	empty suffix will be prepended or appended to that C<search> value). If
		1162	the C<$qname> ends in a dot, then the searchlist will be ignored.
985		1163
986	=item accept => [$type...]	1164	=item accept => [$type...]
987		1165
988	Lists the acceptable result types: only result types in this set will be	1166	Lists the acceptable result types: only result types in this set will be
989	accepted and returned. The default includes the C<$qtype> and nothing	1167	accepted and returned. The default includes the C<$qtype> and nothing
990	else.	1168	else. If this list includes C<cname>, then CNAME-chains will not be
		1169	followed (because you asked for the CNAME record).
991		1170
992	=item class => "class"	1171	=item class => "class"
993		1172
994	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for	1173	Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for
995	hesiod are the only ones making sense). The default is "in", of course.	1174	hesiod are the only ones making sense). The default is "in", of course.
996		1175
997	=back	1176	=back
998		1177
999	Examples:	1178	Examples:
1000		1179
1001	$res->resolve ("ruth.plan9.de", "a", sub {	1180	# full example, you can paste this into perl:
1002	warn Dumper [@_];	1181	use Data::Dumper;
1003	});	1182	use AnyEvent::DNS;
		1183	AnyEvent::DNS::resolver->resolve (
		1184	"google.com", "*", my $cv = AnyEvent->condvar);
		1185	warn Dumper [$cv->recv];
1004		1186
		1187	# shortened result:
1005	[	1188	# [
		1189	# [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com',
		1190	# 2008052701, 7200, 1800, 1209600, 300 ],
1006	[	1191	# [
1007	'ruth.schmorp.de',	1192	# 'google.com', 'txt', 'in',
1008	'a',	1193	# 'v=spf1 include:_netblocks.google.com ~all'
1009	'in',	1194	# ],
1010	'129.13.162.95'	1195	# [ 'google.com', 'a', 'in', '64.233.187.99' ],
		1196	# [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ],
		1197	# [ 'google.com', 'ns', 'in', 'ns2.google.com' ],
1011	]	1198	# ]
		1199
		1200	# resolve a records:
		1201	$res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] });
		1202
		1203	# result:
		1204	# [
		1205	# [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ]
1012	]	1206	# ]
1013		1207
		1208	# resolve any records, but return only a and aaaa records:
1014	$res->resolve ("test1.laendle", "*",	1209	$res->resolve ("test1.laendle", "*",
1015	accept => ["a", "aaaa"],	1210	accept => ["a", "aaaa"],
1016	sub {	1211	sub {
1017	warn Dumper [@_];	1212	warn Dumper [@_];
1018	}	1213	}
1019	);	1214	);
1020		1215
1021	[	1216	# result:
1022	[	1217	# [
1023	'test1.laendle',	1218	# [ 'test1.laendle', 'a', 'in', '10.0.0.255' ],
1024	'a',	1219	# [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ]
1025	'in',
1026	'10.0.0.255'
1027	],
1028	[
1029	'test1.laendle',
1030	'aaaa',
1031	'in',
1032	'3ffe:1900:4545:0002:0240:0000:0000:f7e1'
1033	]	1220	# ]
1034	]
1035		1221
1036	=cut	1222	=cut
1037		1223
1038	sub resolve($%) {	1224	sub resolve($%) {
1039	my $cb = pop;	1225	my $cb = pop;
…		…
1059	$do_search = sub {	1245	$do_search = sub {
1060	@search	1246	@search
1061	or (undef $do_search), (undef $do_req), return $cb->();	1247	or (undef $do_search), (undef $do_req), return $cb->();
1062		1248
1063	(my $name = lc "$qname." . shift @search) =~ s/\.$//;	1249	(my $name = lc "$qname." . shift @search) =~ s/\.$//;
1064	my $depth = 2;	1250	my $depth = 10;
1065		1251
1066	# advance in cname-chain	1252	# advance in cname-chain
1067	$do_req = sub {	1253	$do_req = sub {
1068	$self->request ({	1254	$self->request ({
1069	rd => 1,	1255	rd => 1,
…		…
1107	};	1293	};
1108		1294
1109	$do_search->();	1295	$do_search->();
1110	}	1296	}
1111		1297
		1298	=item $resolver->wait_for_slot ($cb->($resolver))
		1299
		1300	Wait until a free request slot is available and call the callback with the
		1301	resolver object.
		1302
		1303	A request slot is used each time a request is actually sent to the
		1304	nameservers: There are never more than C<max_outstanding> of them.
		1305
		1306	Although you can submit more requests (they will simply be queued until
		1307	a request slot becomes available), sometimes, usually for rate-limiting
		1308	purposes, it is useful to instead wait for a slot before generating the
		1309	request (or simply to know when the request load is low enough so one can
		1310	submit requests again).
		1311
		1312	This is what this method does: The callback will be called when submitting
		1313	a DNS request will not result in that request being queued. The callback
		1314	may or may not generate any requests in response.
		1315
		1316	Note that the callback will only be invoked when the request queue is
		1317	empty, so this does not play well if somebody else keeps the request queue
		1318	full at all times.
		1319
		1320	=cut
		1321
		1322	sub wait_for_slot {
		1323	my ($self, $cb) = @_;
		1324
		1325	push @{ $self->{wait} }, $cb;
		1326	$self->_scheduler;
		1327	}
		1328
1112	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end	1329	use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end
1113		1330
1114	1;	1331	1;
1115		1332
1116	=back	1333	=back
1117		1334
1118	=head1 AUTHOR	1335	=head1 AUTHOR
1119		1336
1120	Marc Lehmann <schmorp@schmorp.de>	1337	Marc Lehmann <schmorp@schmorp.de>
1121	http://home.schmorp.de/	1338	http://home.schmorp.de/
1122		1339
1123	=cut	1340	=cut
1124		1341

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents): Revision 1.42 by root, Thu May 29 06:17:52 2008 UTC vs. Revision 1.65 by root, Thu Jun 5 18:30:08 2008 UTC

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Comparing AnyEvent/lib/AnyEvent/DNS.pm (file contents):
Revision 1.42 by root, Thu May 29 06:17:52 2008 UTC vs.
Revision 1.65 by root, Thu Jun 5 18:30:08 2008 UTC