1 |
root |
1.1 |
=head1 NAME |
2 |
|
|
|
3 |
|
|
AnyEvent::DNS - fully asynchronous DNS resolution |
4 |
|
|
|
5 |
|
|
=head1 SYNOPSIS |
6 |
|
|
|
7 |
|
|
use AnyEvent::DNS; |
8 |
|
|
|
9 |
|
|
=head1 DESCRIPTION |
10 |
|
|
|
11 |
|
|
This module offers both a number of DNS convenience functions as well |
12 |
|
|
as a fully asynchronous and high-performance pure-perl stub resolver. |
13 |
|
|
|
14 |
root |
1.12 |
The stub resolver supports DNS over UDP, optional EDNS0 support for up to |
15 |
|
|
4kiB datagrams and automatically falls back to virtual circuit mode for |
16 |
|
|
large responses. |
17 |
|
|
|
18 |
root |
1.1 |
=head2 CONVENIENCE FUNCTIONS |
19 |
|
|
|
20 |
|
|
=over 4 |
21 |
|
|
|
22 |
|
|
=cut |
23 |
|
|
|
24 |
|
|
package AnyEvent::DNS; |
25 |
|
|
|
26 |
root |
1.3 |
no warnings; |
27 |
root |
1.1 |
use strict; |
28 |
|
|
|
29 |
root |
1.6 |
use AnyEvent::Handle (); |
30 |
root |
1.1 |
|
31 |
root |
1.18 |
=item AnyEvent::DNS::addr $node, $service, $proto, $family, $type, $cb->([$family, $type, $proto, $sockaddr], ...) |
32 |
root |
1.4 |
|
33 |
root |
1.18 |
Tries to resolve the given nodename and service name into protocol families |
34 |
|
|
and sockaddr structures usable to connect to this node and service in a |
35 |
|
|
protocol-independent way. It works remotely similar to the getaddrinfo |
36 |
|
|
posix function. |
37 |
|
|
|
38 |
|
|
C<$node> is either an IPv4 or IPv6 address or a hostname, C<$service> is |
39 |
|
|
either a service name (port name from F</etc/services>) or a numerical |
40 |
|
|
port number. If both C<$node> and C<$service> are names, then SRV records |
41 |
|
|
will be consulted to find the real service, otherwise they will be |
42 |
|
|
used as-is. If you know that the service name is not in your services |
43 |
root |
1.24 |
database, then you can specify the service in the format C<name=port> |
44 |
root |
1.18 |
(e.g. C<http=80>). |
45 |
|
|
|
46 |
|
|
C<$proto> must be a protocol name, currently C<tcp>, C<udp> or |
47 |
|
|
C<sctp>. The default is C<tcp>. |
48 |
|
|
|
49 |
root |
1.24 |
C<$family> must be either C<0> (meaning any protocol is OK), C<4> (use |
50 |
root |
1.20 |
only IPv4) or C<6> (use only IPv6). This setting might be influenced by |
51 |
|
|
C<$ENV{PERL_ANYEVENT_PROTOCOLS}>. |
52 |
root |
1.18 |
|
53 |
|
|
C<$type> must be C<SOCK_STREAM>, C<SOCK_DGRAM> or C<SOCK_SEQPACKET> (or |
54 |
|
|
C<undef> in which case it gets automatically chosen). |
55 |
|
|
|
56 |
|
|
The callback will receive zero or more array references that contain |
57 |
|
|
C<$family, $type, $proto> for use in C<socket> and a binary |
58 |
|
|
C<$sockaddr> for use in C<connect> (or C<bind>). |
59 |
|
|
|
60 |
|
|
The application should try these in the order given. |
61 |
root |
1.4 |
|
62 |
|
|
Example: |
63 |
|
|
|
64 |
root |
1.18 |
AnyEvent::DNS::addr "google.com", "http", 0, undef, undef, sub { ... }; |
65 |
root |
1.4 |
|
66 |
|
|
=item AnyEvent::DNS::a $domain, $cb->(@addrs) |
67 |
|
|
|
68 |
|
|
Tries to resolve the given domain to IPv4 address(es). |
69 |
|
|
|
70 |
root |
1.17 |
=item AnyEvent::DNS::aaaa $domain, $cb->(@addrs) |
71 |
|
|
|
72 |
|
|
Tries to resolve the given domain to IPv6 address(es). |
73 |
|
|
|
74 |
root |
1.4 |
=item AnyEvent::DNS::mx $domain, $cb->(@hostnames) |
75 |
|
|
|
76 |
|
|
Tries to resolve the given domain into a sorted (lower preference value |
77 |
|
|
first) list of domain names. |
78 |
|
|
|
79 |
|
|
=item AnyEvent::DNS::ns $domain, $cb->(@hostnames) |
80 |
|
|
|
81 |
|
|
Tries to resolve the given domain name into a list of name servers. |
82 |
|
|
|
83 |
|
|
=item AnyEvent::DNS::txt $domain, $cb->(@hostnames) |
84 |
|
|
|
85 |
|
|
Tries to resolve the given domain name into a list of text records. |
86 |
|
|
|
87 |
|
|
=item AnyEvent::DNS::srv $service, $proto, $domain, $cb->(@srv_rr) |
88 |
|
|
|
89 |
|
|
Tries to resolve the given service, protocol and domain name into a list |
90 |
|
|
of service records. |
91 |
|
|
|
92 |
root |
1.24 |
Each srv_rr is an array reference with the following contents: |
93 |
root |
1.4 |
C<[$priority, $weight, $transport, $target]>. |
94 |
|
|
|
95 |
|
|
They will be sorted with lowest priority, highest weight first (TODO: |
96 |
root |
1.24 |
should use the RFC algorithm to reorder same-priority records for weight). |
97 |
root |
1.4 |
|
98 |
|
|
Example: |
99 |
|
|
|
100 |
|
|
AnyEvent::DNS::srv "sip", "udp", "schmorp.de", sub { ... |
101 |
|
|
# @_ = ( [10, 10, 5060, "sip1.schmorp.de" ] ) |
102 |
|
|
|
103 |
|
|
=item AnyEvent::DNS::ptr $ipv4_or_6, $cb->(@hostnames) |
104 |
|
|
|
105 |
|
|
Tries to reverse-resolve the given IPv4 or IPv6 address (in textual form) |
106 |
|
|
into it's hostname(s). |
107 |
|
|
|
108 |
|
|
Example: |
109 |
|
|
|
110 |
|
|
AnyEvent::DNS::ptr "2001:500:2f::f", sub { print shift }; |
111 |
|
|
# => f.root-servers.net |
112 |
|
|
|
113 |
root |
1.5 |
=item AnyEvent::DNS::any $domain, $cb->(@rrs) |
114 |
|
|
|
115 |
|
|
Tries to resolve the given domain and passes all resource records found to |
116 |
|
|
the callback. |
117 |
|
|
|
118 |
root |
1.4 |
=cut |
119 |
|
|
|
120 |
|
|
sub resolver; |
121 |
|
|
|
122 |
|
|
sub a($$) { |
123 |
|
|
my ($domain, $cb) = @_; |
124 |
|
|
|
125 |
|
|
resolver->resolve ($domain => "a", sub { |
126 |
|
|
$cb->(map $_->[3], @_); |
127 |
|
|
}); |
128 |
|
|
} |
129 |
|
|
|
130 |
root |
1.17 |
sub aaaa($$) { |
131 |
|
|
my ($domain, $cb) = @_; |
132 |
|
|
|
133 |
|
|
resolver->resolve ($domain => "aaaa", sub { |
134 |
|
|
$cb->(map $_->[3], @_); |
135 |
|
|
}); |
136 |
|
|
} |
137 |
|
|
|
138 |
root |
1.4 |
sub mx($$) { |
139 |
|
|
my ($domain, $cb) = @_; |
140 |
|
|
|
141 |
|
|
resolver->resolve ($domain => "mx", sub { |
142 |
|
|
$cb->(map $_->[4], sort { $a->[3] <=> $b->[3] } @_); |
143 |
|
|
}); |
144 |
|
|
} |
145 |
|
|
|
146 |
|
|
sub ns($$) { |
147 |
|
|
my ($domain, $cb) = @_; |
148 |
|
|
|
149 |
|
|
resolver->resolve ($domain => "ns", sub { |
150 |
|
|
$cb->(map $_->[3], @_); |
151 |
|
|
}); |
152 |
|
|
} |
153 |
|
|
|
154 |
|
|
sub txt($$) { |
155 |
|
|
my ($domain, $cb) = @_; |
156 |
|
|
|
157 |
|
|
resolver->resolve ($domain => "txt", sub { |
158 |
|
|
$cb->(map $_->[3], @_); |
159 |
|
|
}); |
160 |
|
|
} |
161 |
|
|
|
162 |
|
|
sub srv($$$$) { |
163 |
|
|
my ($service, $proto, $domain, $cb) = @_; |
164 |
|
|
|
165 |
|
|
# todo, ask for any and check glue records |
166 |
|
|
resolver->resolve ("_$service._$proto.$domain" => "srv", sub { |
167 |
|
|
$cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] || $b->[4] <=> $a->[4] } @_); |
168 |
|
|
}); |
169 |
|
|
} |
170 |
|
|
|
171 |
|
|
sub ptr($$) { |
172 |
|
|
my ($ip, $cb) = @_; |
173 |
|
|
|
174 |
root |
1.17 |
$ip = AnyEvent::Socket::parse_ip ($ip) |
175 |
|
|
or return $cb->(); |
176 |
root |
1.4 |
|
177 |
root |
1.17 |
if (4 == length $ip) { |
178 |
|
|
$ip = join ".", (reverse split /\./, $ip), "in-addr.arpa."; |
179 |
root |
1.4 |
} else { |
180 |
root |
1.17 |
$ip = join ".", (reverse split //, unpack "H*", $ip), "ip6.arpa."; |
181 |
root |
1.4 |
} |
182 |
|
|
|
183 |
root |
1.17 |
resolver->resolve ($ip => "ptr", sub { |
184 |
root |
1.4 |
$cb->(map $_->[3], @_); |
185 |
|
|
}); |
186 |
|
|
} |
187 |
root |
1.1 |
|
188 |
root |
1.5 |
sub any($$) { |
189 |
|
|
my ($domain, $cb) = @_; |
190 |
|
|
|
191 |
|
|
resolver->resolve ($domain => "*", $cb); |
192 |
|
|
} |
193 |
|
|
|
194 |
root |
1.18 |
############################################################################# |
195 |
|
|
|
196 |
|
|
sub addr($$$$$$) { |
197 |
|
|
my ($node, $service, $proto, $family, $type, $cb) = @_; |
198 |
|
|
|
199 |
root |
1.21 |
unless (&AnyEvent::Socket::AF_INET6) { |
200 |
root |
1.18 |
$family != 6 |
201 |
|
|
or return $cb->(); |
202 |
root |
1.19 |
|
203 |
|
|
$family ||= 4; |
204 |
root |
1.18 |
} |
205 |
|
|
|
206 |
root |
1.20 |
$cb->() if $family == 4 && !$AnyEvent::PROTOCOL{ipv4}; |
207 |
|
|
$cb->() if $family == 6 && !$AnyEvent::PROTOCOL{ipv6}; |
208 |
|
|
|
209 |
|
|
$family ||=4 unless $AnyEvent::PROTOCOL{ipv6}; |
210 |
|
|
$family ||=6 unless $AnyEvent::PROTOCOL{ipv4}; |
211 |
|
|
|
212 |
root |
1.18 |
$proto ||= "tcp"; |
213 |
|
|
$type ||= $proto eq "udp" ? Socket::SOCK_DGRAM : Socket::SOCK_STREAM; |
214 |
|
|
|
215 |
|
|
my $proton = (getprotobyname $proto)[2] |
216 |
|
|
or Carp::croak "$proto: protocol unknown"; |
217 |
|
|
|
218 |
|
|
my $port; |
219 |
|
|
|
220 |
|
|
if ($service =~ /^(\S+)=(\d+)$/) { |
221 |
|
|
($service, $port) = ($1, $2); |
222 |
|
|
} elsif ($service =~ /^\d+$/) { |
223 |
|
|
($service, $port) = (undef, $service); |
224 |
|
|
} else { |
225 |
|
|
$port = (getservbyname $service, $proto)[2] |
226 |
|
|
or Carp::croak "$service/$proto: service unknown"; |
227 |
|
|
} |
228 |
|
|
|
229 |
|
|
my @target = [$node, $port]; |
230 |
|
|
|
231 |
|
|
# resolve a records / provide sockaddr structures |
232 |
|
|
my $resolve = sub { |
233 |
|
|
my @res; |
234 |
|
|
my $cv = AnyEvent->condvar (cb => sub { |
235 |
root |
1.21 |
$cb->( |
236 |
|
|
map $_->[1], |
237 |
|
|
sort { |
238 |
|
|
$AnyEvent::PROTOCOL{$a->[1][0]} <=> $AnyEvent::PROTOCOL{$b->[1][0]} |
239 |
|
|
or $a->[0] <=> $b->[0] |
240 |
|
|
} |
241 |
|
|
@res |
242 |
|
|
) |
243 |
root |
1.18 |
}); |
244 |
|
|
|
245 |
|
|
$cv->begin; |
246 |
|
|
for my $idx (0 .. $#target) { |
247 |
|
|
my ($node, $port) = @{ $target[$idx] }; |
248 |
|
|
|
249 |
|
|
if (my $noden = AnyEvent::Socket::parse_ip ($node)) { |
250 |
|
|
if (4 == length $noden && $family != 6) { |
251 |
|
|
push @res, [$idx, [Socket::AF_INET, $type, $proton, |
252 |
root |
1.21 |
AnyEvent::Socket::pack_sockaddr ($port, $noden)]] |
253 |
root |
1.18 |
} |
254 |
|
|
|
255 |
|
|
if (16 == length $noden && $family != 4) { |
256 |
root |
1.21 |
push @res, [$idx, [&AnyEvent::Socket::AF_INET6, $type, $proton, |
257 |
|
|
AnyEvent::Socket::pack_sockaddr ( $port, $noden)]] |
258 |
root |
1.18 |
} |
259 |
|
|
} else { |
260 |
|
|
# ipv4 |
261 |
|
|
if ($family != 6) { |
262 |
|
|
$cv->begin; |
263 |
|
|
a $node, sub { |
264 |
|
|
push @res, [$idx, [Socket::AF_INET, $type, $proton, |
265 |
root |
1.21 |
AnyEvent::Socket::pack_sockaddr ($port, AnyEvent::Socket::parse_ipv4 ($_))]] |
266 |
root |
1.18 |
for @_; |
267 |
|
|
$cv->end; |
268 |
|
|
}; |
269 |
|
|
} |
270 |
|
|
|
271 |
|
|
# ipv6 |
272 |
|
|
if ($family != 4) { |
273 |
|
|
$cv->begin; |
274 |
|
|
aaaa $node, sub { |
275 |
root |
1.21 |
push @res, [$idx, [&AnyEvent::Socket::AF_INET6, $type, $proton, |
276 |
|
|
AnyEvent::Socket::pack_sockaddr ($port, AnyEvent::Socket::parse_ipv6 ($_))]] |
277 |
root |
1.18 |
for @_; |
278 |
|
|
$cv->end; |
279 |
|
|
}; |
280 |
|
|
} |
281 |
|
|
} |
282 |
|
|
} |
283 |
|
|
$cv->end; |
284 |
|
|
}; |
285 |
|
|
|
286 |
|
|
# try srv records, if applicable |
287 |
root |
1.21 |
if ($node eq "localhost") { |
288 |
root |
1.24 |
@target = (["127.0.0.1", $port], ["::1", $port]); |
289 |
|
|
&$resolve; |
290 |
root |
1.21 |
} elsif (defined $service && !AnyEvent::Socket::parse_ip ($node)) { |
291 |
root |
1.18 |
srv $service, $proto, $node, sub { |
292 |
|
|
my (@srv) = @_; |
293 |
|
|
|
294 |
|
|
# no srv records, continue traditionally |
295 |
|
|
@srv |
296 |
|
|
or return &$resolve; |
297 |
|
|
|
298 |
|
|
# only srv record has "." => abort |
299 |
|
|
$srv[0][2] ne "." || $#srv |
300 |
|
|
or return $cb->(); |
301 |
|
|
|
302 |
|
|
# use srv records then |
303 |
root |
1.21 |
@target = map ["$_->[3].", $_->[2]], |
304 |
root |
1.18 |
grep $_->[3] ne ".", |
305 |
|
|
@srv; |
306 |
|
|
|
307 |
|
|
&$resolve; |
308 |
|
|
}; |
309 |
|
|
} else { |
310 |
|
|
&$resolve; |
311 |
|
|
} |
312 |
|
|
} |
313 |
|
|
|
314 |
|
|
############################################################################# |
315 |
|
|
|
316 |
root |
1.15 |
=back |
317 |
|
|
|
318 |
root |
1.13 |
=head2 LOW-LEVEL DNS EN-/DECODING FUNCTIONS |
319 |
root |
1.1 |
|
320 |
|
|
=over 4 |
321 |
|
|
|
322 |
root |
1.11 |
=item $AnyEvent::DNS::EDNS0 |
323 |
|
|
|
324 |
root |
1.13 |
This variable decides whether dns_pack automatically enables EDNS0 |
325 |
root |
1.24 |
support. By default, this is disabled (C<0>), unless overridden by |
326 |
root |
1.21 |
C<$ENV{PERL_ANYEVENT_EDNS0>), but when set to C<1>, AnyEvent::DNS will use |
327 |
|
|
EDNS0 in all requests. |
328 |
root |
1.11 |
|
329 |
root |
1.1 |
=cut |
330 |
|
|
|
331 |
root |
1.21 |
our $EDNS0 = $ENV{PERL_ANYEVENT_EDNS0} * 1; # set to 1 to enable (partial) edns0 |
332 |
root |
1.10 |
|
333 |
root |
1.1 |
our %opcode_id = ( |
334 |
|
|
query => 0, |
335 |
|
|
iquery => 1, |
336 |
|
|
status => 2, |
337 |
root |
1.5 |
notify => 4, |
338 |
|
|
update => 5, |
339 |
|
|
map +($_ => $_), 3, 6..15 |
340 |
root |
1.1 |
); |
341 |
|
|
|
342 |
|
|
our %opcode_str = reverse %opcode_id; |
343 |
|
|
|
344 |
|
|
our %rcode_id = ( |
345 |
root |
1.5 |
noerror => 0, |
346 |
|
|
formerr => 1, |
347 |
|
|
servfail => 2, |
348 |
|
|
nxdomain => 3, |
349 |
|
|
notimp => 4, |
350 |
|
|
refused => 5, |
351 |
|
|
yxdomain => 6, # Name Exists when it should not [RFC 2136] |
352 |
|
|
yxrrset => 7, # RR Set Exists when it should not [RFC 2136] |
353 |
|
|
nxrrset => 8, # RR Set that should exist does not [RFC 2136] |
354 |
|
|
notauth => 9, # Server Not Authoritative for zone [RFC 2136] |
355 |
|
|
notzone => 10, # Name not contained in zone [RFC 2136] |
356 |
|
|
# EDNS0 16 BADVERS Bad OPT Version [RFC 2671] |
357 |
|
|
# EDNS0 16 BADSIG TSIG Signature Failure [RFC 2845] |
358 |
|
|
# EDNS0 17 BADKEY Key not recognized [RFC 2845] |
359 |
|
|
# EDNS0 18 BADTIME Signature out of time window [RFC 2845] |
360 |
|
|
# EDNS0 19 BADMODE Bad TKEY Mode [RFC 2930] |
361 |
|
|
# EDNS0 20 BADNAME Duplicate key name [RFC 2930] |
362 |
|
|
# EDNS0 21 BADALG Algorithm not supported [RFC 2930] |
363 |
|
|
map +($_ => $_), 11..15 |
364 |
root |
1.1 |
); |
365 |
|
|
|
366 |
|
|
our %rcode_str = reverse %rcode_id; |
367 |
|
|
|
368 |
|
|
our %type_id = ( |
369 |
|
|
a => 1, |
370 |
|
|
ns => 2, |
371 |
|
|
md => 3, |
372 |
|
|
mf => 4, |
373 |
|
|
cname => 5, |
374 |
|
|
soa => 6, |
375 |
|
|
mb => 7, |
376 |
|
|
mg => 8, |
377 |
|
|
mr => 9, |
378 |
|
|
null => 10, |
379 |
|
|
wks => 11, |
380 |
|
|
ptr => 12, |
381 |
|
|
hinfo => 13, |
382 |
|
|
minfo => 14, |
383 |
|
|
mx => 15, |
384 |
|
|
txt => 16, |
385 |
|
|
aaaa => 28, |
386 |
|
|
srv => 33, |
387 |
root |
1.5 |
opt => 41, |
388 |
|
|
spf => 99, |
389 |
|
|
tkey => 249, |
390 |
|
|
tsig => 250, |
391 |
|
|
ixfr => 251, |
392 |
root |
1.1 |
axfr => 252, |
393 |
|
|
mailb => 253, |
394 |
|
|
"*" => 255, |
395 |
|
|
); |
396 |
|
|
|
397 |
|
|
our %type_str = reverse %type_id; |
398 |
|
|
|
399 |
|
|
our %class_id = ( |
400 |
root |
1.5 |
in => 1, |
401 |
|
|
ch => 3, |
402 |
|
|
hs => 4, |
403 |
|
|
none => 254, |
404 |
|
|
"*" => 255, |
405 |
root |
1.1 |
); |
406 |
|
|
|
407 |
|
|
our %class_str = reverse %class_id; |
408 |
|
|
|
409 |
|
|
# names MUST have a trailing dot |
410 |
|
|
sub _enc_qname($) { |
411 |
|
|
pack "(C/a)*", (split /\./, shift), "" |
412 |
|
|
} |
413 |
|
|
|
414 |
|
|
sub _enc_qd() { |
415 |
|
|
(_enc_qname $_->[0]) . pack "nn", |
416 |
|
|
($_->[1] > 0 ? $_->[1] : $type_id {$_->[1]}), |
417 |
|
|
($_->[2] > 0 ? $_->[2] : $class_id{$_->[2] || "in"}) |
418 |
|
|
} |
419 |
|
|
|
420 |
|
|
sub _enc_rr() { |
421 |
|
|
die "encoding of resource records is not supported"; |
422 |
|
|
} |
423 |
|
|
|
424 |
|
|
=item $pkt = AnyEvent::DNS::dns_pack $dns |
425 |
|
|
|
426 |
|
|
Packs a perl data structure into a DNS packet. Reading RFC1034 is strongly |
427 |
|
|
recommended, then everything will be totally clear. Or maybe not. |
428 |
|
|
|
429 |
|
|
Resource records are not yet encodable. |
430 |
|
|
|
431 |
|
|
Examples: |
432 |
|
|
|
433 |
|
|
# very simple request, using lots of default values: |
434 |
|
|
{ rd => 1, qd => [ [ "host.domain", "a"] ] } |
435 |
|
|
|
436 |
|
|
# more complex example, showing how flags etc. are named: |
437 |
|
|
|
438 |
|
|
{ |
439 |
|
|
id => 10000, |
440 |
|
|
op => "query", |
441 |
|
|
rc => "nxdomain", |
442 |
|
|
|
443 |
|
|
# flags |
444 |
|
|
qr => 1, |
445 |
|
|
aa => 0, |
446 |
|
|
tc => 0, |
447 |
|
|
rd => 0, |
448 |
|
|
ra => 0, |
449 |
root |
1.5 |
ad => 0, |
450 |
|
|
cd => 0, |
451 |
root |
1.1 |
|
452 |
|
|
qd => [@rr], # query section |
453 |
|
|
an => [@rr], # answer section |
454 |
|
|
ns => [@rr], # authority section |
455 |
|
|
ar => [@rr], # additional records section |
456 |
|
|
} |
457 |
|
|
|
458 |
|
|
=cut |
459 |
|
|
|
460 |
|
|
sub dns_pack($) { |
461 |
|
|
my ($req) = @_; |
462 |
|
|
|
463 |
root |
1.7 |
pack "nn nnnn a* a* a* a* a*", |
464 |
root |
1.1 |
$req->{id}, |
465 |
|
|
|
466 |
|
|
! !$req->{qr} * 0x8000 |
467 |
|
|
+ $opcode_id{$req->{op}} * 0x0800 |
468 |
|
|
+ ! !$req->{aa} * 0x0400 |
469 |
|
|
+ ! !$req->{tc} * 0x0200 |
470 |
|
|
+ ! !$req->{rd} * 0x0100 |
471 |
|
|
+ ! !$req->{ra} * 0x0080 |
472 |
root |
1.5 |
+ ! !$req->{ad} * 0x0020 |
473 |
|
|
+ ! !$req->{cd} * 0x0010 |
474 |
root |
1.1 |
+ $rcode_id{$req->{rc}} * 0x0001, |
475 |
|
|
|
476 |
|
|
scalar @{ $req->{qd} || [] }, |
477 |
|
|
scalar @{ $req->{an} || [] }, |
478 |
|
|
scalar @{ $req->{ns} || [] }, |
479 |
root |
1.11 |
$EDNS0 + scalar @{ $req->{ar} || [] }, # include EDNS0 option here |
480 |
root |
1.1 |
|
481 |
|
|
(join "", map _enc_qd, @{ $req->{qd} || [] }), |
482 |
|
|
(join "", map _enc_rr, @{ $req->{an} || [] }), |
483 |
|
|
(join "", map _enc_rr, @{ $req->{ns} || [] }), |
484 |
root |
1.7 |
(join "", map _enc_rr, @{ $req->{ar} || [] }), |
485 |
|
|
|
486 |
root |
1.11 |
($EDNS0 ? pack "C nnNn", 0, 41, 4096, 0, 0 : "") # EDNS0, 4kiB udp payload size |
487 |
root |
1.1 |
} |
488 |
|
|
|
489 |
|
|
our $ofs; |
490 |
|
|
our $pkt; |
491 |
|
|
|
492 |
|
|
# bitches |
493 |
|
|
sub _dec_qname { |
494 |
|
|
my @res; |
495 |
|
|
my $redir; |
496 |
|
|
my $ptr = $ofs; |
497 |
|
|
my $cnt; |
498 |
|
|
|
499 |
|
|
while () { |
500 |
|
|
return undef if ++$cnt >= 256; # to avoid DoS attacks |
501 |
|
|
|
502 |
|
|
my $len = ord substr $pkt, $ptr++, 1; |
503 |
|
|
|
504 |
|
|
if ($len & 0xc0) { |
505 |
|
|
$ptr++; |
506 |
|
|
$ofs = $ptr if $ptr > $ofs; |
507 |
|
|
$ptr = (unpack "n", substr $pkt, $ptr - 2, 2) & 0x3fff; |
508 |
|
|
} elsif ($len) { |
509 |
|
|
push @res, substr $pkt, $ptr, $len; |
510 |
|
|
$ptr += $len; |
511 |
|
|
} else { |
512 |
|
|
$ofs = $ptr if $ptr > $ofs; |
513 |
|
|
return join ".", @res; |
514 |
|
|
} |
515 |
|
|
} |
516 |
|
|
} |
517 |
|
|
|
518 |
|
|
sub _dec_qd { |
519 |
|
|
my $qname = _dec_qname; |
520 |
|
|
my ($qt, $qc) = unpack "nn", substr $pkt, $ofs; $ofs += 4; |
521 |
|
|
[$qname, $type_str{$qt} || $qt, $class_str{$qc} || $qc] |
522 |
|
|
} |
523 |
|
|
|
524 |
|
|
our %dec_rr = ( |
525 |
root |
1.17 |
1 => sub { join ".", unpack "C4" }, # a |
526 |
root |
1.1 |
2 => sub { local $ofs = $ofs - length; _dec_qname }, # ns |
527 |
|
|
5 => sub { local $ofs = $ofs - length; _dec_qname }, # cname |
528 |
|
|
6 => sub { |
529 |
|
|
local $ofs = $ofs - length; |
530 |
|
|
my $mname = _dec_qname; |
531 |
|
|
my $rname = _dec_qname; |
532 |
|
|
($mname, $rname, unpack "NNNNN", substr $pkt, $ofs) |
533 |
|
|
}, # soa |
534 |
root |
1.17 |
11 => sub { ((join ".", unpack "C4"), unpack "C a*", substr $_, 4) }, # wks |
535 |
root |
1.1 |
12 => sub { local $ofs = $ofs - length; _dec_qname }, # ptr |
536 |
root |
1.5 |
13 => sub { unpack "C/a C/a", $_ }, # hinfo |
537 |
root |
1.1 |
15 => sub { local $ofs = $ofs + 2 - length; ((unpack "n", $_), _dec_qname) }, # mx |
538 |
root |
1.5 |
16 => sub { unpack "(C/a)*", $_ }, # txt |
539 |
root |
1.17 |
28 => sub { AnyEvent::Socket::format_ip ($_) }, # aaaa |
540 |
root |
1.1 |
33 => sub { local $ofs = $ofs + 6 - length; ((unpack "nnn", $_), _dec_qname) }, # srv |
541 |
root |
1.5 |
99 => sub { unpack "(C/a)*", $_ }, # spf |
542 |
root |
1.1 |
); |
543 |
|
|
|
544 |
|
|
sub _dec_rr { |
545 |
|
|
my $qname = _dec_qname; |
546 |
|
|
|
547 |
|
|
my ($rt, $rc, $ttl, $rdlen) = unpack "nn N n", substr $pkt, $ofs; $ofs += 10; |
548 |
|
|
local $_ = substr $pkt, $ofs, $rdlen; $ofs += $rdlen; |
549 |
|
|
|
550 |
|
|
[ |
551 |
|
|
$qname, |
552 |
|
|
$type_str{$rt} || $rt, |
553 |
|
|
$class_str{$rc} || $rc, |
554 |
|
|
($dec_rr{$rt} || sub { $_ })->(), |
555 |
|
|
] |
556 |
|
|
} |
557 |
|
|
|
558 |
|
|
=item $dns = AnyEvent::DNS::dns_unpack $pkt |
559 |
|
|
|
560 |
|
|
Unpacks a DNS packet into a perl data structure. |
561 |
|
|
|
562 |
|
|
Examples: |
563 |
|
|
|
564 |
root |
1.13 |
# an unsuccessful reply |
565 |
root |
1.1 |
{ |
566 |
|
|
'qd' => [ |
567 |
|
|
[ 'ruth.plan9.de.mach.uni-karlsruhe.de', '*', 'in' ] |
568 |
|
|
], |
569 |
|
|
'rc' => 'nxdomain', |
570 |
|
|
'ar' => [], |
571 |
|
|
'ns' => [ |
572 |
|
|
[ |
573 |
|
|
'uni-karlsruhe.de', |
574 |
|
|
'soa', |
575 |
|
|
'in', |
576 |
|
|
'netserv.rz.uni-karlsruhe.de', |
577 |
|
|
'hostmaster.rz.uni-karlsruhe.de', |
578 |
root |
1.13 |
2008052201, 10800, 1800, 2592000, 86400 |
579 |
root |
1.1 |
] |
580 |
|
|
], |
581 |
|
|
'tc' => '', |
582 |
|
|
'ra' => 1, |
583 |
|
|
'qr' => 1, |
584 |
|
|
'id' => 45915, |
585 |
|
|
'aa' => '', |
586 |
|
|
'an' => [], |
587 |
|
|
'rd' => 1, |
588 |
|
|
'op' => 'query' |
589 |
|
|
} |
590 |
|
|
|
591 |
|
|
# a successful reply |
592 |
|
|
|
593 |
|
|
{ |
594 |
|
|
'qd' => [ [ 'www.google.de', 'a', 'in' ] ], |
595 |
|
|
'rc' => 0, |
596 |
|
|
'ar' => [ |
597 |
|
|
[ 'a.l.google.com', 'a', 'in', '209.85.139.9' ], |
598 |
|
|
[ 'b.l.google.com', 'a', 'in', '64.233.179.9' ], |
599 |
|
|
[ 'c.l.google.com', 'a', 'in', '64.233.161.9' ], |
600 |
|
|
], |
601 |
|
|
'ns' => [ |
602 |
|
|
[ 'l.google.com', 'ns', 'in', 'a.l.google.com' ], |
603 |
|
|
[ 'l.google.com', 'ns', 'in', 'b.l.google.com' ], |
604 |
|
|
], |
605 |
|
|
'tc' => '', |
606 |
|
|
'ra' => 1, |
607 |
|
|
'qr' => 1, |
608 |
|
|
'id' => 64265, |
609 |
|
|
'aa' => '', |
610 |
|
|
'an' => [ |
611 |
|
|
[ 'www.google.de', 'cname', 'in', 'www.google.com' ], |
612 |
|
|
[ 'www.google.com', 'cname', 'in', 'www.l.google.com' ], |
613 |
|
|
[ 'www.l.google.com', 'a', 'in', '66.249.93.104' ], |
614 |
|
|
[ 'www.l.google.com', 'a', 'in', '66.249.93.147' ], |
615 |
|
|
], |
616 |
|
|
'rd' => 1, |
617 |
|
|
'op' => 0 |
618 |
|
|
} |
619 |
|
|
|
620 |
|
|
=cut |
621 |
|
|
|
622 |
|
|
sub dns_unpack($) { |
623 |
|
|
local $pkt = shift; |
624 |
|
|
my ($id, $flags, $qd, $an, $ns, $ar) |
625 |
|
|
= unpack "nn nnnn A*", $pkt; |
626 |
|
|
|
627 |
|
|
local $ofs = 6 * 2; |
628 |
|
|
|
629 |
|
|
{ |
630 |
|
|
id => $id, |
631 |
|
|
qr => ! ! ($flags & 0x8000), |
632 |
|
|
aa => ! ! ($flags & 0x0400), |
633 |
|
|
tc => ! ! ($flags & 0x0200), |
634 |
|
|
rd => ! ! ($flags & 0x0100), |
635 |
|
|
ra => ! ! ($flags & 0x0080), |
636 |
root |
1.5 |
ad => ! ! ($flags & 0x0020), |
637 |
|
|
cd => ! ! ($flags & 0x0010), |
638 |
root |
1.1 |
op => $opcode_str{($flags & 0x001e) >> 11}, |
639 |
|
|
rc => $rcode_str{($flags & 0x000f)}, |
640 |
|
|
|
641 |
|
|
qd => [map _dec_qd, 1 .. $qd], |
642 |
|
|
an => [map _dec_rr, 1 .. $an], |
643 |
|
|
ns => [map _dec_rr, 1 .. $ns], |
644 |
|
|
ar => [map _dec_rr, 1 .. $ar], |
645 |
|
|
} |
646 |
|
|
} |
647 |
|
|
|
648 |
|
|
############################################################################# |
649 |
|
|
|
650 |
|
|
=back |
651 |
|
|
|
652 |
|
|
=head2 THE AnyEvent::DNS RESOLVER CLASS |
653 |
|
|
|
654 |
root |
1.13 |
This is the class which does the actual protocol work. |
655 |
root |
1.1 |
|
656 |
|
|
=over 4 |
657 |
|
|
|
658 |
|
|
=cut |
659 |
|
|
|
660 |
|
|
use Carp (); |
661 |
|
|
use Scalar::Util (); |
662 |
|
|
use Socket (); |
663 |
|
|
|
664 |
|
|
our $NOW; |
665 |
|
|
|
666 |
root |
1.2 |
=item AnyEvent::DNS::resolver |
667 |
|
|
|
668 |
|
|
This function creates and returns a resolver that is ready to use and |
669 |
|
|
should mimic the default resolver for your system as good as possible. |
670 |
|
|
|
671 |
|
|
It only ever creates one resolver and returns this one on subsequent |
672 |
|
|
calls. |
673 |
|
|
|
674 |
|
|
Unless you have special needs, prefer this function over creating your own |
675 |
|
|
resolver object. |
676 |
|
|
|
677 |
|
|
=cut |
678 |
|
|
|
679 |
|
|
our $RESOLVER; |
680 |
|
|
|
681 |
|
|
sub resolver() { |
682 |
|
|
$RESOLVER || do { |
683 |
|
|
$RESOLVER = new AnyEvent::DNS; |
684 |
root |
1.14 |
$RESOLVER->os_config; |
685 |
root |
1.2 |
$RESOLVER |
686 |
|
|
} |
687 |
|
|
} |
688 |
|
|
|
689 |
root |
1.1 |
=item $resolver = new AnyEvent::DNS key => value... |
690 |
|
|
|
691 |
root |
1.6 |
Creates and returns a new resolver. |
692 |
root |
1.2 |
|
693 |
|
|
The following options are supported: |
694 |
root |
1.1 |
|
695 |
|
|
=over 4 |
696 |
|
|
|
697 |
|
|
=item server => [...] |
698 |
|
|
|
699 |
root |
1.24 |
A list of server addresses (default: C<v127.0.0.1>) in network format (4 |
700 |
root |
1.1 |
octets for IPv4, 16 octets for IPv6 - not yet supported). |
701 |
|
|
|
702 |
|
|
=item timeout => [...] |
703 |
|
|
|
704 |
|
|
A list of timeouts to use (also determines the number of retries). To make |
705 |
|
|
three retries with individual time-outs of 2, 5 and 5 seconds, use C<[2, |
706 |
|
|
5, 5]>, which is also the default. |
707 |
|
|
|
708 |
|
|
=item search => [...] |
709 |
|
|
|
710 |
|
|
The default search list of suffixes to append to a domain name (default: none). |
711 |
|
|
|
712 |
root |
1.2 |
=item ndots => $integer |
713 |
root |
1.1 |
|
714 |
|
|
The number of dots (default: C<1>) that a name must have so that the resolver |
715 |
|
|
tries to resolve the name without any suffixes first. |
716 |
|
|
|
717 |
root |
1.2 |
=item max_outstanding => $integer |
718 |
root |
1.1 |
|
719 |
|
|
Most name servers do not handle many parallel requests very well. This option |
720 |
root |
1.24 |
limits the number of outstanding requests to C<$n> (default: C<10>), that means |
721 |
root |
1.1 |
if you request more than this many requests, then the additional requests will be queued |
722 |
|
|
until some other requests have been resolved. |
723 |
|
|
|
724 |
root |
1.13 |
=item reuse => $seconds |
725 |
|
|
|
726 |
root |
1.22 |
The number of seconds (default: C<300>) that a query id cannot be re-used |
727 |
|
|
after a timeout. If there as no time-out then query id's can be reused |
728 |
|
|
immediately. |
729 |
root |
1.13 |
|
730 |
root |
1.1 |
=back |
731 |
|
|
|
732 |
|
|
=cut |
733 |
|
|
|
734 |
|
|
sub new { |
735 |
|
|
my ($class, %arg) = @_; |
736 |
|
|
|
737 |
|
|
socket my $fh, &Socket::AF_INET, &Socket::SOCK_DGRAM, 0 |
738 |
|
|
or Carp::croak "socket: $!"; |
739 |
|
|
|
740 |
|
|
AnyEvent::Util::fh_nonblocking $fh, 1; |
741 |
|
|
|
742 |
|
|
my $self = bless { |
743 |
|
|
server => [v127.0.0.1], |
744 |
|
|
timeout => [2, 5, 5], |
745 |
|
|
search => [], |
746 |
|
|
ndots => 1, |
747 |
|
|
max_outstanding => 10, |
748 |
root |
1.22 |
reuse => 300, # reuse id's after 5 minutes only, if possible |
749 |
root |
1.1 |
%arg, |
750 |
|
|
fh => $fh, |
751 |
|
|
reuse_q => [], |
752 |
|
|
}, $class; |
753 |
|
|
|
754 |
|
|
# search should default to gethostname's domain |
755 |
|
|
# but perl lacks a good posix module |
756 |
|
|
|
757 |
|
|
Scalar::Util::weaken (my $wself = $self); |
758 |
|
|
$self->{rw} = AnyEvent->io (fh => $fh, poll => "r", cb => sub { $wself->_recv }); |
759 |
|
|
|
760 |
|
|
$self->_compile; |
761 |
|
|
|
762 |
|
|
$self |
763 |
|
|
} |
764 |
|
|
|
765 |
|
|
=item $resolver->parse_resolv_conv ($string) |
766 |
|
|
|
767 |
root |
1.24 |
Parses the given string as if it were a F<resolv.conf> file. The following |
768 |
|
|
directives are supported (but not necessarily implemented). |
769 |
root |
1.1 |
|
770 |
|
|
C<#>-style comments, C<nameserver>, C<domain>, C<search>, C<sortlist>, |
771 |
|
|
C<options> (C<timeout>, C<attempts>, C<ndots>). |
772 |
|
|
|
773 |
|
|
Everything else is silently ignored. |
774 |
|
|
|
775 |
|
|
=cut |
776 |
|
|
|
777 |
|
|
sub parse_resolv_conf { |
778 |
|
|
my ($self, $resolvconf) = @_; |
779 |
|
|
|
780 |
|
|
$self->{server} = []; |
781 |
|
|
$self->{search} = []; |
782 |
|
|
|
783 |
|
|
my $attempts; |
784 |
|
|
|
785 |
|
|
for (split /\n/, $resolvconf) { |
786 |
|
|
if (/^\s*#/) { |
787 |
|
|
# comment |
788 |
|
|
} elsif (/^\s*nameserver\s+(\S+)\s*$/i) { |
789 |
|
|
my $ip = $1; |
790 |
|
|
if (AnyEvent::Util::dotted_quad $ip) { |
791 |
|
|
push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip; |
792 |
|
|
} else { |
793 |
|
|
warn "nameserver $ip invalid and ignored\n"; |
794 |
|
|
} |
795 |
|
|
} elsif (/^\s*domain\s+(\S*)\s+$/i) { |
796 |
|
|
$self->{search} = [$1]; |
797 |
|
|
} elsif (/^\s*search\s+(.*?)\s*$/i) { |
798 |
|
|
$self->{search} = [split /\s+/, $1]; |
799 |
|
|
} elsif (/^\s*sortlist\s+(.*?)\s*$/i) { |
800 |
|
|
# ignored, NYI |
801 |
|
|
} elsif (/^\s*options\s+(.*?)\s*$/i) { |
802 |
|
|
for (split /\s+/, $1) { |
803 |
|
|
if (/^timeout:(\d+)$/) { |
804 |
|
|
$self->{timeout} = [$1]; |
805 |
|
|
} elsif (/^attempts:(\d+)$/) { |
806 |
|
|
$attempts = $1; |
807 |
|
|
} elsif (/^ndots:(\d+)$/) { |
808 |
|
|
$self->{ndots} = $1; |
809 |
|
|
} else { |
810 |
|
|
# debug, rotate, no-check-names, inet6 |
811 |
|
|
} |
812 |
|
|
} |
813 |
|
|
} |
814 |
|
|
} |
815 |
|
|
|
816 |
|
|
$self->{timeout} = [($self->{timeout}[0]) x $attempts] |
817 |
|
|
if $attempts; |
818 |
|
|
|
819 |
|
|
$self->_compile; |
820 |
|
|
} |
821 |
|
|
|
822 |
root |
1.14 |
=item $resolver->os_config |
823 |
root |
1.1 |
|
824 |
root |
1.24 |
Tries so load and parse F</etc/resolv.conf> on portable operating systems. Tries various |
825 |
|
|
egregious hacks on windows to force the DNS servers and searchlist out of the system. |
826 |
root |
1.1 |
|
827 |
|
|
=cut |
828 |
|
|
|
829 |
root |
1.14 |
sub os_config { |
830 |
root |
1.1 |
my ($self) = @_; |
831 |
|
|
|
832 |
root |
1.14 |
if ($^O =~ /mswin32|cygwin/i) { |
833 |
|
|
# yeah, it suxx... lets hope DNS is DNS in all locales |
834 |
|
|
|
835 |
|
|
if (open my $fh, "ipconfig /all |") { |
836 |
|
|
delete $self->{server}; |
837 |
|
|
delete $self->{search}; |
838 |
|
|
|
839 |
|
|
while (<$fh>) { |
840 |
|
|
# first DNS.* is suffix list |
841 |
|
|
if (/^\s*DNS/) { |
842 |
|
|
while (/\s+([[:alnum:].\-]+)\s*$/) { |
843 |
|
|
push @{ $self->{search} }, $1; |
844 |
|
|
$_ = <$fh>; |
845 |
|
|
} |
846 |
|
|
last; |
847 |
|
|
} |
848 |
|
|
} |
849 |
|
|
|
850 |
|
|
while (<$fh>) { |
851 |
|
|
# second DNS.* is server address list |
852 |
|
|
if (/^\s*DNS/) { |
853 |
|
|
while (/\s+(\d+\.\d+\.\d+\.\d+)\s*$/) { |
854 |
|
|
my $ip = $1; |
855 |
|
|
push @{ $self->{server} }, AnyEvent::Util::socket_inet_aton $ip |
856 |
|
|
if AnyEvent::Util::dotted_quad $ip; |
857 |
|
|
$_ = <$fh>; |
858 |
|
|
} |
859 |
|
|
last; |
860 |
|
|
} |
861 |
|
|
} |
862 |
|
|
|
863 |
|
|
$self->_compile; |
864 |
|
|
} |
865 |
|
|
} else { |
866 |
|
|
# try resolv.conf everywhere |
867 |
root |
1.1 |
|
868 |
root |
1.14 |
if (open my $fh, "</etc/resolv.conf") { |
869 |
|
|
local $/; |
870 |
|
|
$self->parse_resolv_conf (<$fh>); |
871 |
|
|
} |
872 |
|
|
} |
873 |
root |
1.1 |
} |
874 |
|
|
|
875 |
|
|
sub _compile { |
876 |
|
|
my $self = shift; |
877 |
|
|
|
878 |
|
|
my @retry; |
879 |
|
|
|
880 |
|
|
for my $timeout (@{ $self->{timeout} }) { |
881 |
|
|
for my $server (@{ $self->{server} }) { |
882 |
|
|
push @retry, [$server, $timeout]; |
883 |
|
|
} |
884 |
|
|
} |
885 |
|
|
|
886 |
|
|
$self->{retry} = \@retry; |
887 |
|
|
} |
888 |
|
|
|
889 |
root |
1.6 |
sub _feed { |
890 |
|
|
my ($self, $res) = @_; |
891 |
|
|
|
892 |
|
|
$res = dns_unpack $res |
893 |
|
|
or return; |
894 |
|
|
|
895 |
|
|
my $id = $self->{id}{$res->{id}}; |
896 |
|
|
|
897 |
|
|
return unless ref $id; |
898 |
|
|
|
899 |
|
|
$NOW = time; |
900 |
|
|
$id->[1]->($res); |
901 |
|
|
} |
902 |
|
|
|
903 |
root |
1.1 |
sub _recv { |
904 |
|
|
my ($self) = @_; |
905 |
|
|
|
906 |
root |
1.9 |
while (my $peer = recv $self->{fh}, my $res, 4096, 0) { |
907 |
root |
1.21 |
my ($port, $host) = AnyEvent::Socket::unpack_sockaddr ($peer); |
908 |
root |
1.1 |
|
909 |
|
|
return unless $port == 53 && grep $_ eq $host, @{ $self->{server} }; |
910 |
|
|
|
911 |
root |
1.6 |
$self->_feed ($res); |
912 |
root |
1.1 |
} |
913 |
|
|
} |
914 |
|
|
|
915 |
root |
1.22 |
sub _free_id { |
916 |
|
|
my ($self, $id, $timeout) = @_; |
917 |
|
|
|
918 |
|
|
if ($timeout) { |
919 |
|
|
# we need to block the id for a while |
920 |
|
|
$self->{id}{$id} = 1; |
921 |
|
|
push @{ $self->{reuse_q} }, [$NOW + $self->{reuse}, $id]; |
922 |
|
|
} else { |
923 |
|
|
# we can quickly recycle the id |
924 |
|
|
delete $self->{id}{$id}; |
925 |
|
|
} |
926 |
|
|
|
927 |
|
|
--$self->{outstanding}; |
928 |
|
|
$self->_scheduler; |
929 |
|
|
} |
930 |
|
|
|
931 |
|
|
# execute a single request, involves sending it with timeouts to multiple servers |
932 |
root |
1.1 |
sub _exec { |
933 |
root |
1.22 |
my ($self, $req) = @_; |
934 |
|
|
|
935 |
|
|
my $retry; # of retries |
936 |
|
|
my $do_retry; |
937 |
|
|
|
938 |
|
|
$do_retry = sub { |
939 |
|
|
my $retry_cfg = $self->{retry}[$retry++] |
940 |
|
|
or do { |
941 |
|
|
# failure |
942 |
|
|
$self->_free_id ($req->[2], $retry > 1); |
943 |
|
|
undef $do_retry; return $req->[1]->(); |
944 |
|
|
}; |
945 |
root |
1.1 |
|
946 |
|
|
my ($server, $timeout) = @$retry_cfg; |
947 |
|
|
|
948 |
|
|
$self->{id}{$req->[2]} = [AnyEvent->timer (after => $timeout, cb => sub { |
949 |
|
|
$NOW = time; |
950 |
|
|
|
951 |
|
|
# timeout, try next |
952 |
root |
1.22 |
&$do_retry; |
953 |
root |
1.1 |
}), sub { |
954 |
|
|
my ($res) = @_; |
955 |
|
|
|
956 |
root |
1.6 |
if ($res->{tc}) { |
957 |
|
|
# success, but truncated, so use tcp |
958 |
root |
1.17 |
AnyEvent::Socket::tcp_connect ((Socket::inet_ntoa $server), 53, sub { |
959 |
root |
1.6 |
my ($fh) = @_ |
960 |
root |
1.22 |
or return &$do_retry; |
961 |
root |
1.6 |
|
962 |
|
|
my $handle = new AnyEvent::Handle |
963 |
|
|
fh => $fh, |
964 |
|
|
on_error => sub { |
965 |
|
|
# failure, try next |
966 |
root |
1.22 |
&$do_retry; |
967 |
root |
1.6 |
}; |
968 |
|
|
|
969 |
|
|
$handle->push_write (pack "n/a", $req->[0]); |
970 |
|
|
$handle->push_read_chunk (2, sub { |
971 |
|
|
$handle->unshift_read_chunk ((unpack "n", $_[1]), sub { |
972 |
|
|
$self->_feed ($_[1]); |
973 |
|
|
}); |
974 |
|
|
}); |
975 |
|
|
shutdown $fh, 1; |
976 |
|
|
|
977 |
root |
1.17 |
}, sub { $timeout }); |
978 |
root |
1.1 |
|
979 |
root |
1.6 |
} else { |
980 |
|
|
# success |
981 |
root |
1.22 |
$self->_free_id ($req->[2], $retry > 1); |
982 |
|
|
undef $do_retry; return $req->[1]->($res); |
983 |
root |
1.6 |
} |
984 |
root |
1.1 |
}]; |
985 |
|
|
|
986 |
root |
1.21 |
send $self->{fh}, $req->[0], 0, AnyEvent::Socket::pack_sockaddr (53, $server); |
987 |
root |
1.22 |
}; |
988 |
root |
1.1 |
|
989 |
root |
1.22 |
&$do_retry; |
990 |
root |
1.1 |
} |
991 |
|
|
|
992 |
|
|
sub _scheduler { |
993 |
|
|
my ($self) = @_; |
994 |
|
|
|
995 |
|
|
$NOW = time; |
996 |
|
|
|
997 |
|
|
# first clear id reuse queue |
998 |
|
|
delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] } |
999 |
root |
1.13 |
while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW; |
1000 |
root |
1.1 |
|
1001 |
|
|
while ($self->{outstanding} < $self->{max_outstanding}) { |
1002 |
root |
1.13 |
|
1003 |
|
|
if (@{ $self->{reuse_q} } >= 30000) { |
1004 |
|
|
# we ran out of ID's, wait a bit |
1005 |
|
|
$self->{reuse_to} ||= AnyEvent->timer (after => $self->{reuse_q}[0][0] - $NOW, cb => sub { |
1006 |
|
|
delete $self->{reuse_to}; |
1007 |
|
|
$self->_scheduler; |
1008 |
|
|
}); |
1009 |
|
|
last; |
1010 |
|
|
} |
1011 |
|
|
|
1012 |
root |
1.1 |
my $req = shift @{ $self->{queue} } |
1013 |
|
|
or last; |
1014 |
|
|
|
1015 |
|
|
while () { |
1016 |
|
|
$req->[2] = int rand 65536; |
1017 |
|
|
last unless exists $self->{id}{$req->[2]}; |
1018 |
|
|
} |
1019 |
|
|
|
1020 |
root |
1.22 |
++$self->{outstanding}; |
1021 |
root |
1.1 |
$self->{id}{$req->[2]} = 1; |
1022 |
|
|
substr $req->[0], 0, 2, pack "n", $req->[2]; |
1023 |
|
|
|
1024 |
root |
1.22 |
$self->_exec ($req); |
1025 |
root |
1.1 |
} |
1026 |
|
|
} |
1027 |
|
|
|
1028 |
|
|
=item $resolver->request ($req, $cb->($res)) |
1029 |
|
|
|
1030 |
|
|
Sends a single request (a hash-ref formated as specified for |
1031 |
root |
1.3 |
C<dns_pack>) to the configured nameservers including |
1032 |
root |
1.1 |
retries. Calls the callback with the decoded response packet if a reply |
1033 |
|
|
was received, or no arguments on timeout. |
1034 |
|
|
|
1035 |
|
|
=cut |
1036 |
|
|
|
1037 |
|
|
sub request($$) { |
1038 |
|
|
my ($self, $req, $cb) = @_; |
1039 |
|
|
|
1040 |
root |
1.3 |
push @{ $self->{queue} }, [dns_pack $req, $cb]; |
1041 |
root |
1.1 |
$self->_scheduler; |
1042 |
|
|
} |
1043 |
|
|
|
1044 |
|
|
=item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr)) |
1045 |
|
|
|
1046 |
|
|
Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a |
1047 |
|
|
qtype of "*" is supported and means "any"). |
1048 |
|
|
|
1049 |
|
|
The callback will be invoked with a list of matching result records or |
1050 |
|
|
none on any error or if the name could not be found. |
1051 |
|
|
|
1052 |
|
|
CNAME chains (although illegal) are followed up to a length of 8. |
1053 |
|
|
|
1054 |
root |
1.24 |
Note that this resolver is just a stub resolver: it requires a name server |
1055 |
root |
1.3 |
supporting recursive queries, will not do any recursive queries itself and |
1056 |
|
|
is not secure when used against an untrusted name server. |
1057 |
|
|
|
1058 |
root |
1.1 |
The following options are supported: |
1059 |
|
|
|
1060 |
|
|
=over 4 |
1061 |
|
|
|
1062 |
|
|
=item search => [$suffix...] |
1063 |
|
|
|
1064 |
|
|
Use the given search list (which might be empty), by appending each one |
1065 |
|
|
in turn to the C<$qname>. If this option is missing then the configured |
1066 |
|
|
C<ndots> and C<search> define its value. If the C<$qname> ends in a dot, |
1067 |
root |
1.2 |
then the searchlist will be ignored. |
1068 |
root |
1.1 |
|
1069 |
|
|
=item accept => [$type...] |
1070 |
|
|
|
1071 |
|
|
Lists the acceptable result types: only result types in this set will be |
1072 |
|
|
accepted and returned. The default includes the C<$qtype> and nothing |
1073 |
|
|
else. |
1074 |
|
|
|
1075 |
|
|
=item class => "class" |
1076 |
|
|
|
1077 |
|
|
Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for |
1078 |
root |
1.2 |
hesiod are the only ones making sense). The default is "in", of course. |
1079 |
root |
1.1 |
|
1080 |
|
|
=back |
1081 |
|
|
|
1082 |
|
|
Examples: |
1083 |
|
|
|
1084 |
|
|
$res->resolve ("ruth.plan9.de", "a", sub { |
1085 |
|
|
warn Dumper [@_]; |
1086 |
|
|
}); |
1087 |
|
|
|
1088 |
|
|
[ |
1089 |
|
|
[ |
1090 |
|
|
'ruth.schmorp.de', |
1091 |
|
|
'a', |
1092 |
|
|
'in', |
1093 |
|
|
'129.13.162.95' |
1094 |
|
|
] |
1095 |
|
|
] |
1096 |
|
|
|
1097 |
|
|
$res->resolve ("test1.laendle", "*", |
1098 |
|
|
accept => ["a", "aaaa"], |
1099 |
|
|
sub { |
1100 |
|
|
warn Dumper [@_]; |
1101 |
|
|
} |
1102 |
|
|
); |
1103 |
|
|
|
1104 |
|
|
[ |
1105 |
|
|
[ |
1106 |
|
|
'test1.laendle', |
1107 |
|
|
'a', |
1108 |
|
|
'in', |
1109 |
|
|
'10.0.0.255' |
1110 |
|
|
], |
1111 |
|
|
[ |
1112 |
|
|
'test1.laendle', |
1113 |
|
|
'aaaa', |
1114 |
|
|
'in', |
1115 |
|
|
'3ffe:1900:4545:0002:0240:0000:0000:f7e1' |
1116 |
|
|
] |
1117 |
|
|
] |
1118 |
|
|
|
1119 |
|
|
=cut |
1120 |
|
|
|
1121 |
|
|
sub resolve($%) { |
1122 |
|
|
my $cb = pop; |
1123 |
|
|
my ($self, $qname, $qtype, %opt) = @_; |
1124 |
|
|
|
1125 |
|
|
my @search = $qname =~ s/\.$// |
1126 |
|
|
? "" |
1127 |
|
|
: $opt{search} |
1128 |
|
|
? @{ $opt{search} } |
1129 |
|
|
: ($qname =~ y/.//) >= $self->{ndots} |
1130 |
|
|
? ("", @{ $self->{search} }) |
1131 |
|
|
: (@{ $self->{search} }, ""); |
1132 |
|
|
|
1133 |
|
|
my $class = $opt{class} || "in"; |
1134 |
|
|
|
1135 |
|
|
my %atype = $opt{accept} |
1136 |
|
|
? map +($_ => 1), @{ $opt{accept} } |
1137 |
|
|
: ($qtype => 1); |
1138 |
|
|
|
1139 |
|
|
# advance in searchlist |
1140 |
root |
1.22 |
my ($do_search, $do_req); |
1141 |
|
|
|
1142 |
|
|
$do_search = sub { |
1143 |
root |
1.1 |
@search |
1144 |
root |
1.22 |
or (undef $do_search), (undef $do_req), return $cb->(); |
1145 |
root |
1.1 |
|
1146 |
root |
1.4 |
(my $name = lc "$qname." . shift @search) =~ s/\.$//; |
1147 |
root |
1.1 |
my $depth = 2; |
1148 |
|
|
|
1149 |
|
|
# advance in cname-chain |
1150 |
root |
1.22 |
$do_req = sub { |
1151 |
root |
1.1 |
$self->request ({ |
1152 |
|
|
rd => 1, |
1153 |
|
|
qd => [[$name, $qtype, $class]], |
1154 |
|
|
}, sub { |
1155 |
|
|
my ($res) = @_ |
1156 |
|
|
or return $do_search->(); |
1157 |
|
|
|
1158 |
|
|
my $cname; |
1159 |
|
|
|
1160 |
|
|
while () { |
1161 |
root |
1.2 |
# results found? |
1162 |
root |
1.4 |
my @rr = grep $name eq lc $_->[0] && ($atype{"*"} || $atype{$_->[1]}), @{ $res->{an} }; |
1163 |
root |
1.1 |
|
1164 |
root |
1.22 |
(undef $do_search), (undef $do_req), return $cb->(@rr) |
1165 |
root |
1.1 |
if @rr; |
1166 |
|
|
|
1167 |
|
|
# see if there is a cname we can follow |
1168 |
root |
1.4 |
my @rr = grep $name eq lc $_->[0] && $_->[1] eq "cname", @{ $res->{an} }; |
1169 |
root |
1.1 |
|
1170 |
|
|
if (@rr) { |
1171 |
|
|
$depth-- |
1172 |
|
|
or return $do_search->(); # cname chain too long |
1173 |
|
|
|
1174 |
|
|
$cname = 1; |
1175 |
|
|
$name = $rr[0][3]; |
1176 |
|
|
|
1177 |
|
|
} elsif ($cname) { |
1178 |
|
|
# follow the cname |
1179 |
|
|
return $do_req->(); |
1180 |
|
|
|
1181 |
|
|
} else { |
1182 |
root |
1.2 |
# no, not found anything |
1183 |
root |
1.1 |
return $do_search->(); |
1184 |
|
|
} |
1185 |
|
|
} |
1186 |
|
|
}); |
1187 |
|
|
}; |
1188 |
|
|
|
1189 |
|
|
$do_req->(); |
1190 |
|
|
}; |
1191 |
|
|
|
1192 |
|
|
$do_search->(); |
1193 |
|
|
} |
1194 |
|
|
|
1195 |
root |
1.17 |
use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end |
1196 |
|
|
|
1197 |
root |
1.1 |
1; |
1198 |
|
|
|
1199 |
|
|
=back |
1200 |
|
|
|
1201 |
|
|
=head1 AUTHOR |
1202 |
|
|
|
1203 |
|
|
Marc Lehmann <schmorp@schmorp.de> |
1204 |
|
|
http://home.schmorp.de/ |
1205 |
|
|
|
1206 |
|
|
=cut |
1207 |
|
|
|