1 |
=head1 NAME |
2 |
|
3 |
AnyEvent::MP::Transport - actual transport protocol handler |
4 |
|
5 |
=head1 SYNOPSIS |
6 |
|
7 |
use AnyEvent::MP::Transport; |
8 |
|
9 |
=head1 DESCRIPTION |
10 |
|
11 |
This implements the actual transport protocol for MP (it represents a |
12 |
single link), most of which is considered an implementation detail. |
13 |
|
14 |
See the "PROTOCOL" section below if you want to write another client for |
15 |
this protocol. |
16 |
|
17 |
=head1 FUNCTIONS/METHODS |
18 |
|
19 |
=over 4 |
20 |
|
21 |
=cut |
22 |
|
23 |
package AnyEvent::MP::Transport; |
24 |
|
25 |
use common::sense; |
26 |
|
27 |
use Scalar::Util (); |
28 |
use List::Util (); |
29 |
use MIME::Base64 (); |
30 |
use Storable (); |
31 |
use JSON::XS (); |
32 |
|
33 |
use Digest::MD6 (); |
34 |
use Digest::HMAC_MD6 (); |
35 |
|
36 |
use AE (); |
37 |
use AnyEvent::Socket (); |
38 |
use AnyEvent::Handle 4.92 (); |
39 |
|
40 |
use base Exporter::; |
41 |
|
42 |
our $PROTOCOL_VERSION = 0; |
43 |
|
44 |
=item $listener = mp_listener $host, $port, <constructor-args>, $cb->($transport) |
45 |
|
46 |
Creates a listener on the given host/port using |
47 |
C<AnyEvent::Socket::tcp_server>. |
48 |
|
49 |
See C<new>, below, for constructor arguments. |
50 |
|
51 |
Defaults for peerhost, peerport and fh are provided. |
52 |
|
53 |
=cut |
54 |
|
55 |
sub mp_server($$@) { |
56 |
my $cb = pop; |
57 |
my ($host, $port, @args) = @_; |
58 |
|
59 |
AnyEvent::Socket::tcp_server $host, $port, sub { |
60 |
my ($fh, $host, $port) = @_; |
61 |
|
62 |
$cb->(new AnyEvent::MP::Transport |
63 |
fh => $fh, |
64 |
peerhost => $host, |
65 |
peerport => $port, |
66 |
@args, |
67 |
); |
68 |
} |
69 |
} |
70 |
|
71 |
=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport) |
72 |
|
73 |
=cut |
74 |
|
75 |
sub mp_connect { |
76 |
my $cb = pop; |
77 |
my ($host, $port, @args) = @_; |
78 |
|
79 |
AnyEvent::Socket::tcp_connect $host, $port, sub { |
80 |
my ($fh, $nhost, $nport) = @_; |
81 |
|
82 |
return $cb->() unless $fh; |
83 |
|
84 |
$cb->(new AnyEvent::MP::Transport |
85 |
fh => $fh, |
86 |
peername => $host, |
87 |
peerhost => $nhost, |
88 |
peerport => $nport, |
89 |
@args, |
90 |
); |
91 |
} |
92 |
} |
93 |
|
94 |
=item new AnyEvent::MP::Transport |
95 |
|
96 |
# immediately starts negotiation |
97 |
my $transport = new AnyEvent::MP::Transport |
98 |
# mandatory |
99 |
fh => $filehandle, |
100 |
local_id => $identifier, |
101 |
on_recv => sub { receive-callback }, |
102 |
on_error => sub { error-callback }, |
103 |
|
104 |
# optional |
105 |
secret => "shared secret", |
106 |
on_eof => sub { clean-close-callback }, |
107 |
on_connect => sub { successful-connect-callback }, |
108 |
greeting => { key => value }, |
109 |
|
110 |
# tls support |
111 |
tls_ctx => AnyEvent::TLS, |
112 |
peername => $peername, # for verification |
113 |
; |
114 |
|
115 |
=cut |
116 |
|
117 |
sub LATENCY() { 3 } # assumed max. network latency |
118 |
|
119 |
our @FRAMINGS = qw(json storable); # the framing types we accept and send, in order of preference |
120 |
our @AUTH_SND = qw(hmac_md6_64_256); # auth types we send |
121 |
our @AUTH_RCV = (@AUTH_SND, qw(cleartext)); # auth types we accept |
122 |
|
123 |
#AnyEvent::Handle::register_write_type mp_record => sub { |
124 |
#}; |
125 |
|
126 |
sub new { |
127 |
my ($class, %arg) = @_; |
128 |
|
129 |
my $self = bless \%arg, $class; |
130 |
|
131 |
$self->{queue} = []; |
132 |
|
133 |
{ |
134 |
Scalar::Util::weaken (my $self = $self); |
135 |
|
136 |
$arg{secret} = AnyEvent::MP::Base::default_secret () |
137 |
unless exists $arg{secret}; |
138 |
|
139 |
$arg{timeout} = 30 |
140 |
unless exists $arg{timeout}; |
141 |
|
142 |
$arg{timeout} = 1 + LATENCY |
143 |
if $arg{timeout} < 1 + LATENCY; |
144 |
|
145 |
my $secret = $arg{secret}; |
146 |
|
147 |
if ($secret =~ /-----BEGIN RSA PRIVATE KEY-----.*-----END RSA PRIVATE KEY-----.*-----BEGIN CERTIFICATE-----.*-----END CERTIFICATE-----/s) { |
148 |
# assume TLS mode |
149 |
$arg{tls_ctx} = { |
150 |
sslv2 => 0, |
151 |
sslv3 => 0, |
152 |
tlsv1 => 1, |
153 |
verify => 1, |
154 |
cert => $secret, |
155 |
ca_cert => $secret, |
156 |
verify_require_client_cert => 1, |
157 |
}; |
158 |
} |
159 |
|
160 |
$self->{hdl} = new AnyEvent::Handle |
161 |
fh => delete $arg{fh}, |
162 |
autocork => 1, |
163 |
no_delay => 1, |
164 |
on_error => sub { |
165 |
$self->error ($_[2]); |
166 |
}, |
167 |
rtimeout => $AnyEvent::MP::Base::CONNECT_TIMEOUT, |
168 |
peername => delete $arg{peername}, |
169 |
; |
170 |
|
171 |
my $greeting_kv = $self->{greeting} ||= {}; |
172 |
|
173 |
$self->{local_node} = $AnyEvent::MP::Base::NODE; |
174 |
|
175 |
$greeting_kv->{"tls"} = "1.0" if $arg{tls_ctx}; |
176 |
$greeting_kv->{provider} = "AE-$AnyEvent::MP::Base::VERSION"; |
177 |
$greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport}; |
178 |
$greeting_kv->{timeout} = $arg{timeout}; |
179 |
|
180 |
# send greeting |
181 |
my $lgreeting1 = "aemp;$PROTOCOL_VERSION" |
182 |
. ";$self->{local_node}" |
183 |
. ";" . (join ",", @AUTH_RCV) |
184 |
. ";" . (join ",", @FRAMINGS) |
185 |
. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv); |
186 |
|
187 |
my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), ""; |
188 |
|
189 |
$self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012"); |
190 |
|
191 |
# expect greeting |
192 |
$self->{hdl}->rbuf_max (4 * 1024); |
193 |
$self->{hdl}->push_read (line => sub { |
194 |
my $rgreeting1 = $_[1]; |
195 |
|
196 |
my ($aemp, $version, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1; |
197 |
|
198 |
if ($aemp ne "aemp") { |
199 |
return $self->error ("unparsable greeting"); |
200 |
} elsif ($version != $PROTOCOL_VERSION) { |
201 |
return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)"); |
202 |
} |
203 |
|
204 |
my $s_auth; |
205 |
for my $auth_ (split /,/, $auths) { |
206 |
if (grep $auth_ eq $_, @AUTH_SND) { |
207 |
$s_auth = $auth_; |
208 |
last; |
209 |
} |
210 |
} |
211 |
|
212 |
defined $s_auth |
213 |
or return $self->error ("$auths: no common auth type supported"); |
214 |
|
215 |
die unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm. |
216 |
|
217 |
my $s_framing; |
218 |
for my $framing_ (split /,/, $framings) { |
219 |
if (grep $framing_ eq $_, @FRAMINGS) { |
220 |
$s_framing = $framing_; |
221 |
last; |
222 |
} |
223 |
} |
224 |
|
225 |
defined $s_framing |
226 |
or return $self->error ("$framings: no common framing method supported"); |
227 |
|
228 |
$self->{remote_node} = $rnode; |
229 |
|
230 |
$self->{remote_greeting} = { |
231 |
map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (), |
232 |
@kv |
233 |
}; |
234 |
|
235 |
# read nonce |
236 |
$self->{hdl}->push_read (line => sub { |
237 |
my $rgreeting2 = $_[1]; |
238 |
|
239 |
"$lgreeting1\012$lgreeting2" ne "$rgreeting1\012$rgreeting2" # echo attack? |
240 |
or return $self->error ("authentication error, echo attack?"); |
241 |
|
242 |
my $key = Digest::MD6::md6 $secret; |
243 |
my $lauth; |
244 |
|
245 |
if ($self->{tls_ctx} and 1 == int $self->{remote_greeting}{tls}) { |
246 |
$self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept"; |
247 |
$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx}); |
248 |
$s_auth = "tls"; |
249 |
$lauth = ""; |
250 |
} else { |
251 |
# we currently only support hmac_md6_64_256 |
252 |
$lauth = Digest::HMAC_MD6::hmac_md6_hex $key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256; |
253 |
} |
254 |
|
255 |
$self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012"); |
256 |
|
257 |
# read the authentication response |
258 |
$self->{hdl}->push_read (line => sub { |
259 |
my ($hdl, $rline) = @_; |
260 |
|
261 |
my ($auth_method, $rauth2, $r_framing) = split /;/, $rline; |
262 |
|
263 |
my $rauth = |
264 |
$auth_method eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex $key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256 |
265 |
: $auth_method eq "cleartext" ? unpack "H*", $secret |
266 |
: $auth_method eq "tls" ? ($self->{tls} ? "" : "\012\012") # \012\012 never matches |
267 |
: return $self->error ("$auth_method: fatal, selected unsupported auth method"); |
268 |
|
269 |
if ($rauth2 ne $rauth) { |
270 |
return $self->error ("authentication failure/shared secret mismatch"); |
271 |
} |
272 |
|
273 |
$self->{s_framing} = $s_framing; |
274 |
|
275 |
$hdl->rbuf_max (undef); |
276 |
my $queue = delete $self->{queue}; # we are connected |
277 |
|
278 |
$self->{hdl}->rtimeout ($self->{remote_greeting}{timeout}); |
279 |
$self->{hdl}->wtimeout ($arg{timeout} - LATENCY); |
280 |
$self->{hdl}->on_wtimeout (sub { $self->send (["", "devnull"]) }); |
281 |
|
282 |
$self->connected; |
283 |
|
284 |
# send queued messages |
285 |
$self->send ($_) |
286 |
for @$queue; |
287 |
|
288 |
# receive handling |
289 |
my $src_node = $self->{node}; |
290 |
|
291 |
my $rmsg; $rmsg = sub { |
292 |
$_[0]->push_read ($r_framing => $rmsg); |
293 |
|
294 |
local $AnyEvent::MP::Base::SRCNODE = $src_node; |
295 |
AnyEvent::MP::Base::_inject (@{ $_[1] }); |
296 |
}; |
297 |
$hdl->push_read ($r_framing => $rmsg); |
298 |
}); |
299 |
}); |
300 |
}); |
301 |
} |
302 |
|
303 |
$self |
304 |
} |
305 |
|
306 |
sub error { |
307 |
my ($self, $msg) = @_; |
308 |
|
309 |
if ($self->{node} && $self->{node}{transport} == $self) { |
310 |
#TODO: store error, but do not instantly fail |
311 |
$self->{node}->fail (transport_error => $self->{node}{noderef}, $msg); |
312 |
$self->{node}->clr_transport; |
313 |
} |
314 |
$AnyEvent::MP::Base::WARN->("$self->{peerhost}:$self->{peerport}: $msg"); |
315 |
$self->destroy; |
316 |
} |
317 |
|
318 |
sub connected { |
319 |
my ($self) = @_; |
320 |
|
321 |
if (ref $AnyEvent::MP::Base::SLAVE) { |
322 |
# first connect with a master node |
323 |
my $via = $self->{remote_node}; |
324 |
$via =~ s/,/!/g; |
325 |
$AnyEvent::MP::Base::NODE .= "\@$via"; |
326 |
$AnyEvent::MP::Base::NODE{$AnyEvent::MP::Base::NODE} = $AnyEvent::MP::Base::NODE{""}; |
327 |
$AnyEvent::MP::Base::SLAVE->(); |
328 |
} |
329 |
|
330 |
if ($self->{local_node} ne $AnyEvent::MP::Base::NODE) { |
331 |
# node changed its name since first greeting |
332 |
$self->send (["", iam => $AnyEvent::MP::Base::NODE]); |
333 |
} |
334 |
|
335 |
my $node = AnyEvent::MP::Base::add_node ($self->{remote_node}); |
336 |
Scalar::Util::weaken ($self->{node} = $node); |
337 |
$node->set_transport ($self); |
338 |
} |
339 |
|
340 |
sub send { |
341 |
$_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]); |
342 |
} |
343 |
|
344 |
sub destroy { |
345 |
my ($self) = @_; |
346 |
|
347 |
$self->{hdl}->destroy |
348 |
if $self->{hdl}; |
349 |
} |
350 |
|
351 |
sub DESTROY { |
352 |
my ($self) = @_; |
353 |
|
354 |
$self->destroy; |
355 |
} |
356 |
|
357 |
=back |
358 |
|
359 |
=head1 PROTOCOL |
360 |
|
361 |
The protocol is relatively simple, and consists of three phases which are |
362 |
symmetrical for both sides: greeting (followed by optionally switching to |
363 |
TLS mode), authentication and packet exchange. |
364 |
|
365 |
the protocol is designed to allow both full-text and binary streams. |
366 |
|
367 |
The greeting consists of two text lines that are ended by either an ASCII |
368 |
CR LF pair, or a single ASCII LF (recommended). |
369 |
|
370 |
=head2 GREETING |
371 |
|
372 |
All the lines until after authentication must not exceed 4kb in length, |
373 |
including delimiter. Afterwards there is no limit on the packet size that |
374 |
can be received. |
375 |
|
376 |
=head3 First Greeting Line |
377 |
|
378 |
Example: |
379 |
|
380 |
aemp;0;fec.4a7720fc;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256;json,storable;provider=AE-0.0 |
381 |
|
382 |
The first line contains strings separated (not ended) by C<;> |
383 |
characters. The first even ixtrings are fixed by the protocol, the |
384 |
remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;> |
385 |
characters themselves. |
386 |
|
387 |
The fixed strings are: |
388 |
|
389 |
=over 4 |
390 |
|
391 |
=item protocol identification |
392 |
|
393 |
The constant C<aemp> to identify the protocol. |
394 |
|
395 |
=item protocol version |
396 |
|
397 |
The protocol version supported by this end, currently C<0>. If the |
398 |
versions don't match then no communication is possible. Minor extensions |
399 |
are supposed to be handled through additional key-value pairs. |
400 |
|
401 |
=item the node endpoint descriptors |
402 |
|
403 |
for public nodes, this is a comma-separated list of protocol endpoints, |
404 |
i.e., the noderef. For slave nodes, this is a unique identifier of the |
405 |
form C<slave/nonce>. |
406 |
|
407 |
=item the acceptable authentication methods |
408 |
|
409 |
A comma-separated list of authentication methods supported by the |
410 |
node. Note that AnyEvent::MP supports a C<hex_secret> authentication |
411 |
method that accepts a cleartext password (hex-encoded), but will not use |
412 |
this auth method itself. |
413 |
|
414 |
The receiving side should choose the first auth method it supports. |
415 |
|
416 |
=item the acceptable framing formats |
417 |
|
418 |
A comma-separated list of packet encoding/framign formats understood. The |
419 |
receiving side should choose the first framing format it supports for |
420 |
sending packets (which might be different from the format it has to accept). |
421 |
|
422 |
=back |
423 |
|
424 |
The remaining arguments are C<KEY=VALUE> pairs. The following key-value |
425 |
pairs are known at this time: |
426 |
|
427 |
=over 4 |
428 |
|
429 |
=item provider=<module-version> |
430 |
|
431 |
The software provider for this implementation. For AnyEvent::MP, this is |
432 |
C<AE-0.0> or whatever version it currently is at. |
433 |
|
434 |
=item peeraddr=<host>:<port> |
435 |
|
436 |
The peer address (socket address of the other side) as seen locally, in the same format |
437 |
as noderef endpoints. |
438 |
|
439 |
=item tls=<major>.<minor> |
440 |
|
441 |
Indicates that the other side supports TLS (version should be 1.0) and |
442 |
wishes to do a TLS handshake. |
443 |
|
444 |
=item timeout=<seconds> |
445 |
|
446 |
The amount of time after which this node should be detected as dead unless |
447 |
some data has been received. The node is responsible to send traffic |
448 |
reasonably more often than this interval (such as every timeout minus five |
449 |
seconds). |
450 |
|
451 |
=back |
452 |
|
453 |
=head3 Second Greeting Line |
454 |
|
455 |
After this greeting line there will be a second line containing a |
456 |
cryptographic nonce, i.e. random data of high quality. To keep the |
457 |
protocol text-only, these are usually 32 base64-encoded octets, but |
458 |
it could be anything that doesn't contain any ASCII CR or ASCII LF |
459 |
characters. |
460 |
|
461 |
I<< The two nonces B<must> be different, and an aemp implementation |
462 |
B<must> check and fail when they are identical >>. |
463 |
|
464 |
Example of a nonce line: |
465 |
|
466 |
p/I122ql7kJR8lumW3lXlXCeBnyDAvz8NQo3x5IFowE4 |
467 |
|
468 |
=head2 TLS handshake |
469 |
|
470 |
I<< If, after the handshake, both sides indicate interest in TLS, then the |
471 |
connection B<must> use TLS, or fail. >> |
472 |
|
473 |
Both sides compare their nonces, and the side who sent the lower nonce |
474 |
value ("string" comparison on the raw octet values) becomes the client, |
475 |
and the one with the higher nonce the server. |
476 |
|
477 |
=head2 AUTHENTICATION PHASE |
478 |
|
479 |
After the greeting is received (and the optional TLS handshake), |
480 |
the authentication phase begins, which consists of sending a single |
481 |
C<;>-separated line with three fixed strings and any number of |
482 |
C<KEY=VALUE> pairs. |
483 |
|
484 |
The three fixed strings are: |
485 |
|
486 |
=over 4 |
487 |
|
488 |
=item the authentication method chosen |
489 |
|
490 |
This must be one of the methods offered by the other side in the greeting. |
491 |
|
492 |
The currently supported authentication methods are: |
493 |
|
494 |
=over 4 |
495 |
|
496 |
=item cleartext |
497 |
|
498 |
This is simply the shared secret, lowercase-hex-encoded. This method is of |
499 |
course very insecure, unless TLS is used, which is why this module will |
500 |
accept, but not generate, cleartext auth replies. |
501 |
|
502 |
=item hmac_md6_64_256 |
503 |
|
504 |
This method uses an MD6 HMAC with 64 bit blocksize and 256 bit hash. First, the shared secret |
505 |
is hashed with MD6: |
506 |
|
507 |
key = MD6 (secret) |
508 |
|
509 |
This secret is then used to generate the "local auth reply", by taking |
510 |
the two local greeting lines and the two remote greeting lines (without |
511 |
line endings), appending \012 to all of them, concatenating them and |
512 |
calculating the MD6 HMAC with the key. |
513 |
|
514 |
lauth = HMAC_MD6 key, "lgreeting1\012lgreeting2\012rgreeting1\012rgreeting2\012" |
515 |
|
516 |
This authentication token is then lowercase-hex-encoded and sent to the |
517 |
other side. |
518 |
|
519 |
Then the remote auth reply is generated using the same method, but local |
520 |
and remote greeting lines swapped: |
521 |
|
522 |
rauth = HMAC_MD6 key, "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012" |
523 |
|
524 |
This is the token that is expected from the other side. |
525 |
|
526 |
=item tls |
527 |
|
528 |
This type is only valid iff TLS was enabled and the TLS handshake |
529 |
was successful. It has no authentication data, as the server/client |
530 |
certificate was successfully verified. |
531 |
|
532 |
Implementations supporting TLS I<must> accept this authentication type. |
533 |
|
534 |
=back |
535 |
|
536 |
=item the authentication data |
537 |
|
538 |
The authentication data itself, usually base64 or hex-encoded data, see |
539 |
above. |
540 |
|
541 |
=item the framing protocol chosen |
542 |
|
543 |
This must be one of the framing protocols offered by the other side in the |
544 |
greeting. Each side must accept the choice of the other side. |
545 |
|
546 |
=back |
547 |
|
548 |
Example of an authentication reply: |
549 |
|
550 |
hmac_md6_64_256;363d5175df38bd9eaddd3f6ca18aa1c0c4aa22f0da245ac638d048398c26b8d3;json |
551 |
|
552 |
=head2 DATA PHASE |
553 |
|
554 |
After this, packets get exchanged using the chosen framing protocol. It is |
555 |
quite possible that both sides use a different framing protocol. |
556 |
|
557 |
=head2 FULL EXAMPLE |
558 |
|
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This is an actual protocol dump of a handshake, followed by a single data |
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packet. The greater than/less than lines indicate the direction of the |
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transfer only. |
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|
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> aemp;0;nndKd+gn;10.0.0.1:4040;hmac_md6_64_256,cleartext;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:1235 |
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> sRG8bbc4TDbkpvH8FTP4HBs87OhepH6VuApoZqXXskuG |
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< aemp;0;nmpKd+gh;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256,cleartext;json,storable;provider=AE-0.0;peeraddr=127.0.0.1:58760 |
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< dCEUcL/LJVSTJcx8byEsOzrwhzJYOq+L3YcopA5T6EAo |
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> hmac_md6_64_256;9513d4b258975accfcb2ab7532b83690e9c119a502c612203332a591c7237788;json |
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< hmac_md6_64_256;0298d6ba2240faabb2b2e881cf86b97d70a113ca74a87dc006f9f1e9d3010f90;json |
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> ["","lookup","pinger","10.0.0.1:4040#nndKd+gn.a","resolved"] |
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|
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=head1 SEE ALSO |
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|
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L<AnyEvent>. |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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|
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=cut |
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|
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1 |
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|