| … | |
… | |
| 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 = 4.1; |
| 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, $cb->(@addrs) |
| 45 | |
45 | |
| … | |
… | |
| 68 | of service records. |
68 | of service records. |
| 69 | |
69 | |
| 70 | Each srv_rr is an array reference with the following contents: |
70 | Each srv_rr is an array reference with the following contents: |
| 71 | C<[$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($$$$) { |
162 | sub srv($$$$) { |
| 145 | my ($service, $proto, $domain, $cb) = @_; |
163 | my ($service, $proto, $domain, $cb) = @_; |
| 146 | |
164 | |
| 147 | # todo, ask for any and check glue records |
165 | # todo, ask for any and check glue records |
| 148 | resolver->resolve ("_$service._$proto.$domain" => "srv", sub { |
166 | resolver->resolve ("_$service._$proto.$domain" => "srv", sub { |
| 149 | $cb->(map [@$_[3,4,5,6]], sort { $a->[3] <=> $b->[3] || $b->[4] <=> $a->[4] } @_); |
167 | my @res; |
|
|
168 | |
|
|
169 | # classify by priority |
|
|
170 | my %pri; |
|
|
171 | push @{ $pri{$_->[3]} }, [ @$_[3,4,5,6] ] |
|
|
172 | for @_; |
|
|
173 | |
|
|
174 | # order by priority |
|
|
175 | for my $pri (sort { $a->[0] <=> $b->[0] } keys %pri) { |
|
|
176 | # order by weight |
|
|
177 | my @rr = sort { $a->[1] <=> $b->[1] } @{ delete $pri{$pri} }; |
|
|
178 | |
|
|
179 | my $sum; $sum += $_->[1] for @rr; |
|
|
180 | |
|
|
181 | while (@rr) { |
|
|
182 | my $w = int rand $sum + 1; |
|
|
183 | for (0 .. $#rr) { |
|
|
184 | if (($w -= $rr[$_][1]) <= 0) { |
|
|
185 | $sum -= $rr[$_][1]; |
|
|
186 | push @res, splice @rr, $_, 1, (); |
|
|
187 | last; |
|
|
188 | } |
|
|
189 | } |
|
|
190 | } |
|
|
191 | } |
|
|
192 | |
|
|
193 | $cb->(@res); |
| 150 | }); |
194 | }); |
| 151 | } |
195 | } |
| 152 | |
196 | |
| 153 | sub ptr($$) { |
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: |
| … | |
… | |
| 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; |
| … | |
… | |
| 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 |
| … | |
… | |
| 614 | server => [], |
723 | server => [], |
| 615 | timeout => [2, 5, 5], |
724 | timeout => [2, 5, 5], |
| 616 | search => [], |
725 | search => [], |
| 617 | ndots => 1, |
726 | ndots => 1, |
| 618 | max_outstanding => 10, |
727 | max_outstanding => 10, |
| 619 | reuse => 300, # reuse id's after 5 minutes only, if possible |
728 | reuse => 300, |
| 620 | %arg, |
729 | %arg, |
| 621 | reuse_q => [], |
730 | reuse_q => [], |
| 622 | }, $class; |
731 | }, $class; |
| 623 | |
732 | |
| 624 | # search should default to gethostname's domain |
733 | # search should default to gethostname's domain |
| … | |
… | |
| 729 | # - the registry thing needs separate code on win32 native vs. cygwin |
838 | # - the registry thing needs separate code on win32 native vs. cygwin |
| 730 | # - the registry layout differs between windows versions |
839 | # - the registry layout differs between windows versions |
| 731 | # - calling windows api functions doesn't work on cygwin |
840 | # - calling windows api functions doesn't work on cygwin |
| 732 | # - ipconfig uses locale-specific messages |
841 | # - ipconfig uses locale-specific messages |
| 733 | |
842 | |
| 734 | # we use ipconfig parsing because, despite all it's brokenness, |
843 | # we use ipconfig parsing because, despite all its brokenness, |
| 735 | # it seems most stable in practise. |
844 | # it seems most stable in practise. |
| 736 | # for good measure, we append a fallback nameserver to our list. |
845 | # for good measure, we append a fallback nameserver to our list. |
| 737 | |
846 | |
| 738 | if (open my $fh, "ipconfig /all |") { |
847 | if (open my $fh, "ipconfig /all |") { |
| 739 | # parsing strategy: we go through the output and look for |
848 | # parsing strategy: we go through the output and look for |
| … | |
… | |
| 748 | } elsif (/^\S/ || /^\s[^:]{16,}: /) { |
857 | } elsif (/^\S/ || /^\s[^:]{16,}: /) { |
| 749 | $dns = 0; |
858 | $dns = 0; |
| 750 | } |
859 | } |
| 751 | if ($dns && /^\s*(\S+)\s*$/) { |
860 | if ($dns && /^\s*(\S+)\s*$/) { |
| 752 | my $s = $1; |
861 | my $s = $1; |
| 753 | $s =~ s/%\d+(?!\S)//; # get rid of scope id |
862 | $s =~ s/%\d+(?!\S)//; # get rid of ipv6 scope id |
| 754 | if (my $ipn = AnyEvent::Socket::parse_address ($s)) { |
863 | if (my $ipn = AnyEvent::Socket::parse_address ($s)) { |
| 755 | push @{ $self->{server} }, $ipn; |
864 | push @{ $self->{server} }, $ipn; |
| 756 | } else { |
865 | } else { |
| 757 | push @{ $self->{search} }, $s; |
866 | push @{ $self->{search} }, $s; |
| 758 | } |
867 | } |
| … | |
… | |
| 770 | if (open my $fh, "</etc/resolv.conf") { |
879 | if (open my $fh, "</etc/resolv.conf") { |
| 771 | local $/; |
880 | local $/; |
| 772 | $self->parse_resolv_conf (<$fh>); |
881 | $self->parse_resolv_conf (<$fh>); |
| 773 | } |
882 | } |
| 774 | } |
883 | } |
|
|
884 | } |
|
|
885 | |
|
|
886 | =item $resolver->timeout ($timeout, ...) |
|
|
887 | |
|
|
888 | Sets the timeout values. See the C<timeout> constructor argument (and note |
|
|
889 | that this method uses the values itself, not an array-reference). |
|
|
890 | |
|
|
891 | =cut |
|
|
892 | |
|
|
893 | sub timeout { |
|
|
894 | my ($self, @timeout) = @_; |
|
|
895 | |
|
|
896 | $self->{timeout} = \@timeout; |
|
|
897 | $self->_compile; |
|
|
898 | } |
|
|
899 | |
|
|
900 | =item $resolver->max_outstanding ($nrequests) |
|
|
901 | |
|
|
902 | Sets the maximum number of outstanding requests to C<$nrequests>. See the |
|
|
903 | C<max_outstanding> constructor argument. |
|
|
904 | |
|
|
905 | =cut |
|
|
906 | |
|
|
907 | sub max_outstanding { |
|
|
908 | my ($self, $max) = @_; |
|
|
909 | |
|
|
910 | $self->{max_outstanding} = $max; |
|
|
911 | $self->_scheduler; |
| 775 | } |
912 | } |
| 776 | |
913 | |
| 777 | sub _compile { |
914 | sub _compile { |
| 778 | my $self = shift; |
915 | my $self = shift; |
| 779 | |
916 | |
| … | |
… | |
| 865 | my ($res) = @_; |
1002 | my ($res) = @_; |
| 866 | |
1003 | |
| 867 | if ($res->{tc}) { |
1004 | if ($res->{tc}) { |
| 868 | # success, but truncated, so use tcp |
1005 | # success, but truncated, so use tcp |
| 869 | AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub { |
1006 | AnyEvent::Socket::tcp_connect (AnyEvent::Socket::format_address ($server), DOMAIN_PORT, sub { |
|
|
1007 | return unless $do_retry; # some other request could have invalidated us already |
|
|
1008 | |
| 870 | my ($fh) = @_ |
1009 | my ($fh) = @_ |
| 871 | or return &$do_retry; |
1010 | or return &$do_retry; |
| 872 | |
1011 | |
| 873 | my $handle = new AnyEvent::Handle |
1012 | my $handle; $handle = new AnyEvent::Handle |
| 874 | fh => $fh, |
1013 | fh => $fh, |
|
|
1014 | timeout => $timeout, |
| 875 | on_error => sub { |
1015 | on_error => sub { |
|
|
1016 | undef $handle; |
|
|
1017 | return unless $do_retry; # some other request could have invalidated us already |
| 876 | # failure, try next |
1018 | # failure, try next |
| 877 | &$do_retry; |
1019 | &$do_retry; |
| 878 | }; |
1020 | }; |
| 879 | |
1021 | |
| 880 | $handle->push_write (pack "n/a", $req->[0]); |
1022 | $handle->push_write (pack "n/a", $req->[0]); |
| 881 | $handle->push_read (chunk => 2, sub { |
1023 | $handle->push_read (chunk => 2, sub { |
| 882 | $handle->unshift_read (chunk => (unpack "n", $_[1]), sub { |
1024 | $handle->unshift_read (chunk => (unpack "n", $_[1]), sub { |
|
|
1025 | undef $handle; |
| 883 | $self->_feed ($_[1]); |
1026 | $self->_feed ($_[1]); |
| 884 | }); |
1027 | }); |
| 885 | }); |
1028 | }); |
| 886 | shutdown $fh, 1; |
|
|
| 887 | |
1029 | |
| 888 | }, sub { $timeout }); |
1030 | }, sub { $timeout }); |
| 889 | |
1031 | |
| 890 | } else { |
1032 | } else { |
| 891 | # success |
1033 | # success |
| … | |
… | |
| 907 | } |
1049 | } |
| 908 | |
1050 | |
| 909 | sub _scheduler { |
1051 | sub _scheduler { |
| 910 | my ($self) = @_; |
1052 | my ($self) = @_; |
| 911 | |
1053 | |
|
|
1054 | no strict 'refs'; |
|
|
1055 | |
| 912 | $NOW = time; |
1056 | $NOW = time; |
| 913 | |
1057 | |
| 914 | # first clear id reuse queue |
1058 | # first clear id reuse queue |
| 915 | delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] } |
1059 | delete $self->{id}{ (shift @{ $self->{reuse_q} })->[1] } |
| 916 | while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW; |
1060 | while @{ $self->{reuse_q} } && $self->{reuse_q}[0][0] <= $NOW; |
| … | |
… | |
| 924 | $self->_scheduler; |
1068 | $self->_scheduler; |
| 925 | }); |
1069 | }); |
| 926 | last; |
1070 | last; |
| 927 | } |
1071 | } |
| 928 | |
1072 | |
| 929 | my $req = shift @{ $self->{queue} } |
1073 | if (my $req = shift @{ $self->{queue} }) { |
| 930 | or last; |
1074 | # found a request in the queue, execute it |
| 931 | |
|
|
| 932 | while () { |
1075 | while () { |
| 933 | $req->[2] = int rand 65536; |
1076 | $req->[2] = int rand 65536; |
| 934 | last unless exists $self->{id}{$req->[2]}; |
1077 | last unless exists $self->{id}{$req->[2]}; |
|
|
1078 | } |
|
|
1079 | |
|
|
1080 | ++$self->{outstanding}; |
|
|
1081 | $self->{id}{$req->[2]} = 1; |
|
|
1082 | substr $req->[0], 0, 2, pack "n", $req->[2]; |
|
|
1083 | |
|
|
1084 | $self->_exec ($req); |
|
|
1085 | |
|
|
1086 | } elsif (my $cb = shift @{ $self->{wait} }) { |
|
|
1087 | # found a wait_for_slot callback, call that one first |
|
|
1088 | $cb->($self); |
|
|
1089 | |
|
|
1090 | } else { |
|
|
1091 | # nothing to do, just exit |
|
|
1092 | last; |
| 935 | } |
1093 | } |
| 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 | } |
1094 | } |
| 943 | } |
1095 | } |
| 944 | |
1096 | |
| 945 | =item $resolver->request ($req, $cb->($res)) |
1097 | =item $resolver->request ($req, $cb->($res)) |
| 946 | |
1098 | |
|
|
1099 | This is the main low-level workhorse for sending DNS requests. |
|
|
1100 | |
| 947 | Sends a single request (a hash-ref formated as specified for |
1101 | This function sends a single request (a hash-ref formated as specified |
| 948 | C<dns_pack>) to the configured nameservers including |
1102 | for C<dns_pack>) to the configured nameservers in turn until it gets a |
|
|
1103 | response. It handles timeouts, retries and automatically falls back to |
|
|
1104 | virtual circuit mode (TCP) when it receives a truncated reply. |
|
|
1105 | |
| 949 | retries. Calls the callback with the decoded response packet if a reply |
1106 | Calls the callback with the decoded response packet if a reply was |
| 950 | was received, or no arguments on timeout. |
1107 | received, or no arguments in case none of the servers answered. |
| 951 | |
1108 | |
| 952 | =cut |
1109 | =cut |
| 953 | |
1110 | |
| 954 | sub request($$) { |
1111 | sub request($$) { |
| 955 | my ($self, $req, $cb) = @_; |
1112 | my ($self, $req, $cb) = @_; |
| … | |
… | |
| 958 | $self->_scheduler; |
1115 | $self->_scheduler; |
| 959 | } |
1116 | } |
| 960 | |
1117 | |
| 961 | =item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr)) |
1118 | =item $resolver->resolve ($qname, $qtype, %options, $cb->($rcode, @rr)) |
| 962 | |
1119 | |
| 963 | Queries the DNS for the given domain name C<$qname> of type C<$qtype> (a |
1120 | Queries the DNS for the given domain name C<$qname> of type C<$qtype>. |
| 964 | qtype of "*" is supported and means "any"). |
1121 | |
|
|
1122 | A C<$qtype> is either a numerical query type (e.g. C<1> for A records) or |
|
|
1123 | a lowercase name (you have to look at the source to see which aliases are |
|
|
1124 | supported, but all types from RFC 1035, C<aaaa>, C<srv>, C<spf> and a few |
|
|
1125 | more are known to this module). A C<$qtype> of "*" is supported and means |
|
|
1126 | "any" record type. |
| 965 | |
1127 | |
| 966 | The callback will be invoked with a list of matching result records or |
1128 | 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. |
1129 | none on any error or if the name could not be found. |
| 968 | |
1130 | |
| 969 | CNAME chains (although illegal) are followed up to a length of 8. |
1131 | CNAME chains (although illegal) are followed up to a length of 8. |
|
|
1132 | |
|
|
1133 | The callback will be invoked with an result code in string form (noerror, |
|
|
1134 | formerr, servfail, nxdomain, notimp, refused and so on), or numerical |
|
|
1135 | form if the result code is not supported. The remaining arguments are |
|
|
1136 | arraryefs of the form C<[$name, $type, $class, @data>], where C<$name> is |
|
|
1137 | the domain name, C<$type> a type string or number, C<$class> a class name |
|
|
1138 | and @data is resource-record-dependent data. For C<a> records, this will |
|
|
1139 | be the textual IPv4 addresses, for C<ns> or C<cname> records this will be |
|
|
1140 | a domain name, for C<txt> records these are all the strings and so on. |
|
|
1141 | |
|
|
1142 | All types mentioned in RFC 1035, C<aaaa>, C<srv>, C<naptr> and C<spf> are |
|
|
1143 | decoded. All resource records not known to this module will have |
|
|
1144 | the raw C<rdata> field as fourth entry. |
| 970 | |
1145 | |
| 971 | Note that this resolver is just a stub resolver: it requires a name server |
1146 | 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 |
1147 | supporting recursive queries, will not do any recursive queries itself and |
| 973 | is not secure when used against an untrusted name server. |
1148 | is not secure when used against an untrusted name server. |
| 974 | |
1149 | |
| … | |
… | |
| 978 | |
1153 | |
| 979 | =item search => [$suffix...] |
1154 | =item search => [$suffix...] |
| 980 | |
1155 | |
| 981 | Use the given search list (which might be empty), by appending each one |
1156 | Use the given search list (which might be empty), by appending each one |
| 982 | in turn to the C<$qname>. If this option is missing then the configured |
1157 | in turn to the C<$qname>. If this option is missing then the configured |
| 983 | C<ndots> and C<search> define its value. If the C<$qname> ends in a dot, |
1158 | C<ndots> and C<search> values define its value (depending on C<ndots>, the |
| 984 | then the searchlist will be ignored. |
1159 | empty suffix will be prepended or appended to that C<search> value). If |
|
|
1160 | the C<$qname> ends in a dot, then the searchlist will be ignored. |
| 985 | |
1161 | |
| 986 | =item accept => [$type...] |
1162 | =item accept => [$type...] |
| 987 | |
1163 | |
| 988 | Lists the acceptable result types: only result types in this set will be |
1164 | Lists the acceptable result types: only result types in this set will be |
| 989 | accepted and returned. The default includes the C<$qtype> and nothing |
1165 | accepted and returned. The default includes the C<$qtype> and nothing |
| 990 | else. |
1166 | else. If this list includes C<cname>, then CNAME-chains will not be |
|
|
1167 | followed (because you asked for the CNAME record). |
| 991 | |
1168 | |
| 992 | =item class => "class" |
1169 | =item class => "class" |
| 993 | |
1170 | |
| 994 | Specify the query class ("in" for internet, "ch" for chaosnet and "hs" for |
1171 | 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. |
1172 | hesiod are the only ones making sense). The default is "in", of course. |
| 996 | |
1173 | |
| 997 | =back |
1174 | =back |
| 998 | |
1175 | |
| 999 | Examples: |
1176 | Examples: |
| 1000 | |
1177 | |
| 1001 | $res->resolve ("ruth.plan9.de", "a", sub { |
1178 | # full example, you can paste this into perl: |
| 1002 | warn Dumper [@_]; |
1179 | use Data::Dumper; |
| 1003 | }); |
1180 | use AnyEvent::DNS; |
|
|
1181 | AnyEvent::DNS::resolver->resolve ( |
|
|
1182 | "google.com", "*", my $cv = AnyEvent->condvar); |
|
|
1183 | warn Dumper [$cv->recv]; |
| 1004 | |
1184 | |
|
|
1185 | # shortened result: |
| 1005 | [ |
1186 | # [ |
|
|
1187 | # [ 'google.com', 'soa', 'in', 'ns1.google.com', 'dns-admin.google.com', |
|
|
1188 | # 2008052701, 7200, 1800, 1209600, 300 ], |
| 1006 | [ |
1189 | # [ |
| 1007 | 'ruth.schmorp.de', |
1190 | # 'google.com', 'txt', 'in', |
| 1008 | 'a', |
1191 | # 'v=spf1 include:_netblocks.google.com ~all' |
| 1009 | 'in', |
1192 | # ], |
| 1010 | '129.13.162.95' |
1193 | # [ 'google.com', 'a', 'in', '64.233.187.99' ], |
|
|
1194 | # [ 'google.com', 'mx', 'in', 10, 'smtp2.google.com' ], |
|
|
1195 | # [ 'google.com', 'ns', 'in', 'ns2.google.com' ], |
| 1011 | ] |
1196 | # ] |
|
|
1197 | |
|
|
1198 | # resolve a records: |
|
|
1199 | $res->resolve ("ruth.plan9.de", "a", sub { warn Dumper [@_] }); |
|
|
1200 | |
|
|
1201 | # result: |
|
|
1202 | # [ |
|
|
1203 | # [ 'ruth.schmorp.de', 'a', 'in', '129.13.162.95' ] |
| 1012 | ] |
1204 | # ] |
| 1013 | |
1205 | |
|
|
1206 | # resolve any records, but return only a and aaaa records: |
| 1014 | $res->resolve ("test1.laendle", "*", |
1207 | $res->resolve ("test1.laendle", "*", |
| 1015 | accept => ["a", "aaaa"], |
1208 | accept => ["a", "aaaa"], |
| 1016 | sub { |
1209 | sub { |
| 1017 | warn Dumper [@_]; |
1210 | warn Dumper [@_]; |
| 1018 | } |
1211 | } |
| 1019 | ); |
1212 | ); |
| 1020 | |
1213 | |
| 1021 | [ |
1214 | # result: |
| 1022 | [ |
1215 | # [ |
| 1023 | 'test1.laendle', |
1216 | # [ 'test1.laendle', 'a', 'in', '10.0.0.255' ], |
| 1024 | 'a', |
1217 | # [ 'test1.laendle', 'aaaa', 'in', '3ffe:1900:4545:0002:0240:0000:0000:f7e1' ] |
| 1025 | 'in', |
|
|
| 1026 | '10.0.0.255' |
|
|
| 1027 | ], |
|
|
| 1028 | [ |
|
|
| 1029 | 'test1.laendle', |
|
|
| 1030 | 'aaaa', |
|
|
| 1031 | 'in', |
|
|
| 1032 | '3ffe:1900:4545:0002:0240:0000:0000:f7e1' |
|
|
| 1033 | ] |
1218 | # ] |
| 1034 | ] |
|
|
| 1035 | |
1219 | |
| 1036 | =cut |
1220 | =cut |
| 1037 | |
1221 | |
| 1038 | sub resolve($%) { |
1222 | sub resolve($%) { |
| 1039 | my $cb = pop; |
1223 | my $cb = pop; |
| … | |
… | |
| 1107 | }; |
1291 | }; |
| 1108 | |
1292 | |
| 1109 | $do_search->(); |
1293 | $do_search->(); |
| 1110 | } |
1294 | } |
| 1111 | |
1295 | |
|
|
1296 | =item $resolver->wait_for_slot ($cb->($resolver)) |
|
|
1297 | |
|
|
1298 | Wait until a free request slot is available and call the callback with the |
|
|
1299 | resolver object. |
|
|
1300 | |
|
|
1301 | A request slot is used each time a request is actually sent to the |
|
|
1302 | nameservers: There are never more than C<max_outstanding> of them. |
|
|
1303 | |
|
|
1304 | Although you can submit more requests (they will simply be queued until |
|
|
1305 | a request slot becomes available), sometimes, usually for rate-limiting |
|
|
1306 | purposes, it is useful to instead wait for a slot before generating the |
|
|
1307 | request (or simply to know when the request load is low enough so one can |
|
|
1308 | submit requests again). |
|
|
1309 | |
|
|
1310 | This is what this method does: The callback will be called when submitting |
|
|
1311 | a DNS request will not result in that request being queued. The callback |
|
|
1312 | may or may not generate any requests in response. |
|
|
1313 | |
|
|
1314 | Note that the callback will only be invoked when the request queue is |
|
|
1315 | empty, so this does not play well if somebody else keeps the request queue |
|
|
1316 | full at all times. |
|
|
1317 | |
|
|
1318 | =cut |
|
|
1319 | |
|
|
1320 | sub wait_for_slot { |
|
|
1321 | my ($self, $cb) = @_; |
|
|
1322 | |
|
|
1323 | push @{ $self->{wait} }, $cb; |
|
|
1324 | $self->_scheduler; |
|
|
1325 | } |
|
|
1326 | |
| 1112 | use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end |
1327 | use AnyEvent::Socket (); # circular dependency, so do not import anything and do it at the end |
| 1113 | |
1328 | |
| 1114 | 1; |
1329 | 1; |
| 1115 | |
1330 | |
| 1116 | =back |
1331 | =back |
