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 module implements (and documents) the actual transport protocol for |
12 |
AEMP. |
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 AnyEvent::MP::Config (); |
41 |
|
42 |
our $PROTOCOL_VERSION = 0; |
43 |
|
44 |
=item $listener = mp_listener $host, $port, <constructor-args> |
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 ($host, $port, %arg) = @_; |
57 |
|
58 |
AnyEvent::Socket::tcp_server $host, $port, sub { |
59 |
my ($fh, $host, $port) = @_; |
60 |
|
61 |
my $tp = new AnyEvent::MP::Transport |
62 |
fh => $fh, |
63 |
peerhost => $host, |
64 |
peerport => $port, |
65 |
%arg, |
66 |
; |
67 |
$tp->{keepalive} = $tp; |
68 |
}, delete $arg{prepare} |
69 |
} |
70 |
|
71 |
=item $guard = mp_connect $host, $port, <constructor-args>, $cb->($transport) |
72 |
|
73 |
=cut |
74 |
|
75 |
sub mp_connect { |
76 |
my $release = pop; |
77 |
my ($host, $port, @args) = @_; |
78 |
|
79 |
my $state; |
80 |
|
81 |
$state = AnyEvent::Socket::tcp_connect $host, $port, my$x=sub { |
82 |
my ($fh, $nhost, $nport) = @_; |
83 |
|
84 |
return $release->() unless $fh; |
85 |
|
86 |
$state = new AnyEvent::MP::Transport |
87 |
fh => $fh, |
88 |
peername => $host, |
89 |
peerhost => $nhost, |
90 |
peerport => $nport, |
91 |
release => $release, |
92 |
@args, |
93 |
; |
94 |
}; |
95 |
|
96 |
\$state |
97 |
} |
98 |
|
99 |
=item new AnyEvent::MP::Transport |
100 |
|
101 |
# immediately starts negotiation |
102 |
my $transport = new AnyEvent::MP::Transport |
103 |
# mandatory |
104 |
fh => $filehandle, |
105 |
local_id => $identifier, |
106 |
on_recv => sub { receive-callback }, |
107 |
on_error => sub { error-callback }, |
108 |
|
109 |
# optional |
110 |
on_eof => sub { clean-close-callback }, |
111 |
on_connect => sub { successful-connect-callback }, |
112 |
greeting => { key => value }, |
113 |
|
114 |
# tls support |
115 |
tls_ctx => AnyEvent::TLS, |
116 |
peername => $peername, # for verification |
117 |
; |
118 |
|
119 |
=cut |
120 |
|
121 |
sub new { |
122 |
my ($class, %arg) = @_; |
123 |
|
124 |
my $self = bless \%arg, $class; |
125 |
|
126 |
$self->{queue} = []; |
127 |
|
128 |
{ |
129 |
Scalar::Util::weaken (my $self = $self); |
130 |
|
131 |
my $config = $AnyEvent::MP::Kernel::CONFIG; |
132 |
|
133 |
my $timeout = $config->{monitor_timeout}; |
134 |
my $lframing = $config->{data_format}; |
135 |
my $auth_snd = $config->{auth_offer}; |
136 |
my $auth_rcv = $config->{auth_accept}; |
137 |
|
138 |
$self->{secret} = $config->{secret} |
139 |
unless exists $self->{secret}; |
140 |
|
141 |
my $secret = $self->{secret}; |
142 |
|
143 |
if (exists $config->{cert}) { |
144 |
$self->{tls_ctx} = { |
145 |
sslv2 => 0, |
146 |
sslv3 => 0, |
147 |
tlsv1 => 1, |
148 |
verify => 1, |
149 |
cert => $config->{cert}, |
150 |
ca_cert => $config->{cert}, |
151 |
verify_require_client_cert => 1, |
152 |
}; |
153 |
} |
154 |
|
155 |
$self->{hdl} = new AnyEvent::Handle |
156 |
fh => delete $self->{fh}, |
157 |
autocork => 1, |
158 |
no_delay => 1, |
159 |
keepalive => 1, |
160 |
on_error => sub { |
161 |
$self->error ($_[2]); |
162 |
}, |
163 |
rtimeout => $timeout, |
164 |
peername => delete $self->{peername}, |
165 |
; |
166 |
|
167 |
my $greeting_kv = $self->{greeting} ||= {}; |
168 |
|
169 |
$self->{local_node} ||= $AnyEvent::MP::Kernel::NODE; |
170 |
|
171 |
$greeting_kv->{tls} = "1.0" if $self->{tls_ctx}; |
172 |
$greeting_kv->{provider} = "AE-$AnyEvent::MP::Kernel::VERSION"; |
173 |
$greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport}; |
174 |
$greeting_kv->{timeout} = $self->{timeout}; |
175 |
|
176 |
# send greeting |
177 |
my $lgreeting1 = "aemp;$PROTOCOL_VERSION" |
178 |
. ";$self->{local_node}" |
179 |
. ";" . (join ",", @$auth_rcv) |
180 |
. ";" . (join ",", @$lframing) |
181 |
. (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv); |
182 |
|
183 |
my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Kernel::nonce (66), ""; |
184 |
|
185 |
$self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012"); |
186 |
|
187 |
# expect greeting |
188 |
$self->{hdl}->rbuf_max (4 * 1024); |
189 |
$self->{hdl}->push_read (line => sub { |
190 |
my $rgreeting1 = $_[1]; |
191 |
|
192 |
my ($aemp, $version, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1; |
193 |
|
194 |
if ($aemp ne "aemp") { |
195 |
return $self->error ("unparsable greeting"); |
196 |
} elsif ($version != $PROTOCOL_VERSION) { |
197 |
return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)"); |
198 |
} elsif ($rnode eq $self->{local_node}) { |
199 |
AnyEvent::MP::Global::avoid_seed ($self->{seed}) |
200 |
if exists $self->{seed}; |
201 |
|
202 |
return $self->error ("I refuse to talk to myself"); |
203 |
} elsif ($AnyEvent::MP::Kernel::NODE{$rnode} && $AnyEvent::MP::Kernel::NODE{$rnode}{transport}) { |
204 |
return $self->error ("$rnode already connected, not connecting again."); |
205 |
} |
206 |
|
207 |
$self->{remote_node} = $rnode; |
208 |
|
209 |
$self->{remote_greeting} = { |
210 |
map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (), |
211 |
@kv |
212 |
}; |
213 |
|
214 |
# read nonce |
215 |
$self->{hdl}->push_read (line => sub { |
216 |
my $rgreeting2 = $_[1]; |
217 |
|
218 |
"$lgreeting1\012$lgreeting2" ne "$rgreeting1\012$rgreeting2" # echo attack? |
219 |
or return $self->error ("authentication error, echo attack?"); |
220 |
|
221 |
my $tls = $self->{tls_ctx} && 1 == int $self->{remote_greeting}{tls}; |
222 |
|
223 |
my $s_auth; |
224 |
for my $auth_ (split /,/, $auths) { |
225 |
if (grep $auth_ eq $_, @$auth_snd and ($auth_ !~ /^tls_/ or $tls)) { |
226 |
$s_auth = $auth_; |
227 |
last; |
228 |
} |
229 |
} |
230 |
|
231 |
defined $s_auth |
232 |
or return $self->error ("$auths: no common auth type supported"); |
233 |
|
234 |
my $s_framing; |
235 |
for my $framing_ (split /,/, $framings) { |
236 |
if (grep $framing_ eq $_, @$lframing) { |
237 |
$s_framing = $framing_; |
238 |
last; |
239 |
} |
240 |
} |
241 |
|
242 |
defined $s_framing |
243 |
or return $self->error ("$framings: no common framing method supported"); |
244 |
|
245 |
my $key; |
246 |
my $lauth; |
247 |
|
248 |
if ($tls) { |
249 |
$self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept"; |
250 |
$self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx}); |
251 |
|
252 |
$lauth = |
253 |
$s_auth eq "tls_anon" ? "" |
254 |
: $s_auth eq "tls_md6_64_256" ? Digest::MD6::md6_hex "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012" |
255 |
: return $self->error ("$s_auth: fatal, selected unsupported snd auth method"); |
256 |
|
257 |
} elsif (length $secret) { |
258 |
return $self->error ("$s_auth: fatal, selected unsupported snd auth method") |
259 |
unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm. |
260 |
|
261 |
$key = Digest::MD6::md6 $secret; |
262 |
# we currently only support hmac_md6_64_256 |
263 |
$lauth = Digest::HMAC_MD6::hmac_md6_hex $key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256; |
264 |
|
265 |
} else { |
266 |
return $self->error ("unable to handshake TLS and no shared secret configured"); |
267 |
} |
268 |
|
269 |
$self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012"); |
270 |
|
271 |
# read the authentication response |
272 |
$self->{hdl}->push_read (line => sub { |
273 |
my ($hdl, $rline) = @_; |
274 |
|
275 |
my ($auth_method, $rauth2, $r_framing) = split /;/, $rline; |
276 |
|
277 |
my $rauth = |
278 |
$auth_method eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex $key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256 |
279 |
: $auth_method eq "cleartext" ? unpack "H*", $secret |
280 |
: $auth_method eq "tls_anon" ? ($tls ? "" : "\012\012") # \012\012 never matches |
281 |
: $auth_method eq "tls_md6_64_256" ? ($tls ? Digest::MD6::md6_hex "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012" : "\012\012") |
282 |
: return $self->error ("$auth_method: fatal, selected unsupported rcv auth method"); |
283 |
|
284 |
if ($rauth2 ne $rauth) { |
285 |
return $self->error ("authentication failure/shared secret mismatch"); |
286 |
} |
287 |
|
288 |
$self->{s_framing} = $s_framing; |
289 |
|
290 |
$hdl->rbuf_max (undef); |
291 |
|
292 |
# we rely on TCP retransmit timeouts and keepalives |
293 |
$self->{hdl}->rtimeout (undef); |
294 |
|
295 |
# except listener-less nodes, they need to continuously probe |
296 |
unless (@$AnyEvent::MP::Kernel::LISTENER) { |
297 |
$self->{hdl}->wtimeout ($timeout); |
298 |
$self->{hdl}->on_wtimeout (sub { $self->send ([]) }); |
299 |
} |
300 |
|
301 |
$self->{remote_greeting}{untrusted} = 1 |
302 |
if $auth_method eq "tls_anon"; |
303 |
|
304 |
my $queue = delete $self->{queue}; # we are connected |
305 |
|
306 |
$self->connected; |
307 |
|
308 |
# send queued messages |
309 |
$self->send ($_) |
310 |
for @$queue; |
311 |
|
312 |
# receive handling |
313 |
my $src_node = $self->{node}; |
314 |
my $rmsg; $rmsg = $self->{rmsg} = sub { |
315 |
$_[0]->push_read ($r_framing => $rmsg); |
316 |
|
317 |
local $AnyEvent::MP::Kernel::SRCNODE = $src_node; |
318 |
AnyEvent::MP::Kernel::_inject (@{ $_[1] }); |
319 |
}; |
320 |
$hdl->push_read ($r_framing => $rmsg); |
321 |
|
322 |
Scalar::Util::weaken $rmsg; |
323 |
Scalar::Util::weaken $src_node; |
324 |
}); |
325 |
}); |
326 |
}); |
327 |
} |
328 |
|
329 |
$self |
330 |
} |
331 |
|
332 |
sub error { |
333 |
my ($self, $msg) = @_; |
334 |
|
335 |
delete $self->{keepalive}; |
336 |
|
337 |
$AnyEvent::MP::Kernel::WARN->(9, "$self->{peerhost}:$self->{peerport} $msg");#d# |
338 |
|
339 |
$self->{node}->transport_error (transport_error => $self->{node}{id}, $msg) |
340 |
if $self->{node} && $self->{node}{transport} == $self; |
341 |
|
342 |
(delete $self->{release})->() |
343 |
if exists $self->{release}; |
344 |
|
345 |
# $AnyEvent::MP::Kernel::WARN->(7, "$self->{peerhost}:$self->{peerport}: $msg"); |
346 |
$self->destroy; |
347 |
} |
348 |
|
349 |
sub connected { |
350 |
my ($self) = @_; |
351 |
|
352 |
delete $self->{keepalive}; |
353 |
|
354 |
(delete $self->{release})->() |
355 |
if exists $self->{release}; |
356 |
|
357 |
$AnyEvent::MP::Kernel::WARN->(9, "$self->{peerhost}:$self->{peerport} connected as $self->{remote_node}"); |
358 |
|
359 |
my $node = AnyEvent::MP::Kernel::add_node ($self->{remote_node}); |
360 |
Scalar::Util::weaken ($self->{node} = $node); |
361 |
$node->transport_connect ($self); |
362 |
} |
363 |
|
364 |
sub send { |
365 |
$_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]); |
366 |
} |
367 |
|
368 |
sub destroy { |
369 |
my ($self) = @_; |
370 |
|
371 |
(delete $self->{release})->() |
372 |
if exists $self->{release}; |
373 |
|
374 |
$self->{hdl}->destroy |
375 |
if $self->{hdl}; |
376 |
} |
377 |
|
378 |
sub DESTROY { |
379 |
my ($self) = @_; |
380 |
|
381 |
$self->destroy; |
382 |
} |
383 |
|
384 |
=back |
385 |
|
386 |
=head1 PROTOCOL |
387 |
|
388 |
The AEMP protocol is relatively simple, and consists of three phases which |
389 |
are symmetrical for both sides: greeting (followed by optionally switching |
390 |
to TLS mode), authentication and packet exchange. |
391 |
|
392 |
The protocol is designed to allow both full-text and binary streams. |
393 |
|
394 |
The greeting consists of two text lines that are ended by either an ASCII |
395 |
CR LF pair, or a single ASCII LF (recommended). |
396 |
|
397 |
=head2 GREETING |
398 |
|
399 |
All the lines until after authentication must not exceed 4kb in length, |
400 |
including line delimiter. Afterwards there is no limit on the packet size |
401 |
that can be received. |
402 |
|
403 |
=head3 First Greeting Line |
404 |
|
405 |
Example: |
406 |
|
407 |
aemp;0;rain;tls_md6_64_256,hmac_md6_64_256,tls_anon,cleartext;json,storable;timeout=12;peeraddr=10.0.0.1:48082 |
408 |
|
409 |
The first line contains strings separated (not ended) by C<;> |
410 |
characters. The first five strings are fixed by the protocol, the |
411 |
remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;> |
412 |
characters themselves (when escaping is needed, use C<%3b> to represent |
413 |
C<;> and C<%25> to represent C<%>)- |
414 |
|
415 |
The fixed strings are: |
416 |
|
417 |
=over 4 |
418 |
|
419 |
=item protocol identification |
420 |
|
421 |
The constant C<aemp> to identify this protocol. |
422 |
|
423 |
=item protocol version |
424 |
|
425 |
The protocol version supported by this end, currently C<0>. If the |
426 |
versions don't match then no communication is possible. Minor extensions |
427 |
are supposed to be handled through additional key-value pairs. |
428 |
|
429 |
=item the node ID |
430 |
|
431 |
This is the node ID of the connecting node. |
432 |
|
433 |
=item the acceptable authentication methods |
434 |
|
435 |
A comma-separated list of authentication methods supported by the |
436 |
node. Note that AnyEvent::MP supports a C<hex_secret> authentication |
437 |
method that accepts a clear-text password (hex-encoded), but will not use |
438 |
this authentication method itself. |
439 |
|
440 |
The receiving side should choose the first authentication method it |
441 |
supports. |
442 |
|
443 |
=item the acceptable framing formats |
444 |
|
445 |
A comma-separated list of packet encoding/framing formats understood. The |
446 |
receiving side should choose the first framing format it supports for |
447 |
sending packets (which might be different from the format it has to accept). |
448 |
|
449 |
=back |
450 |
|
451 |
The remaining arguments are C<KEY=VALUE> pairs. The following key-value |
452 |
pairs are known at this time: |
453 |
|
454 |
=over 4 |
455 |
|
456 |
=item provider=<module-version> |
457 |
|
458 |
The software provider for this implementation. For AnyEvent::MP, this is |
459 |
C<AE-0.0> or whatever version it currently is at. |
460 |
|
461 |
=item peeraddr=<host>:<port> |
462 |
|
463 |
The peer address (socket address of the other side) as seen locally. |
464 |
|
465 |
=item tls=<major>.<minor> |
466 |
|
467 |
Indicates that the other side supports TLS (version should be 1.0) and |
468 |
wishes to do a TLS handshake. |
469 |
|
470 |
=back |
471 |
|
472 |
=head3 Second Greeting Line |
473 |
|
474 |
After this greeting line there will be a second line containing a |
475 |
cryptographic nonce, i.e. random data of high quality. To keep the |
476 |
protocol text-only, these are usually 32 base64-encoded octets, but |
477 |
it could be anything that doesn't contain any ASCII CR or ASCII LF |
478 |
characters. |
479 |
|
480 |
I<< The two nonces B<must> be different, and an aemp implementation |
481 |
B<must> check and fail when they are identical >>. |
482 |
|
483 |
Example of a nonce line (yes, it's random-looking because it is random |
484 |
data): |
485 |
|
486 |
2XYhdG7/O6epFa4wuP0ujAEx1rXYWRcOypjUYK7eF6yWAQr7gwIN9m/2+mVvBrTPXz5GJDgfGm9d8QRABAbmAP/s |
487 |
|
488 |
=head2 TLS handshake |
489 |
|
490 |
I<< If, after the handshake, both sides indicate interest in TLS, then the |
491 |
connection B<must> use TLS, or fail to continue. >> |
492 |
|
493 |
Both sides compare their nonces, and the side who sent the lower nonce |
494 |
value ("string" comparison on the raw octet values) becomes the client, |
495 |
and the one with the higher nonce the server. |
496 |
|
497 |
=head2 AUTHENTICATION PHASE |
498 |
|
499 |
After the greeting is received (and the optional TLS handshake), |
500 |
the authentication phase begins, which consists of sending a single |
501 |
C<;>-separated line with three fixed strings and any number of |
502 |
C<KEY=VALUE> pairs. |
503 |
|
504 |
The three fixed strings are: |
505 |
|
506 |
=over 4 |
507 |
|
508 |
=item the authentication method chosen |
509 |
|
510 |
This must be one of the methods offered by the other side in the greeting. |
511 |
|
512 |
Note that all methods starting with C<tls_> are only valid I<iff> TLS was |
513 |
successfully handshaked (and to be secure the implementation must enforce |
514 |
this). |
515 |
|
516 |
The currently supported authentication methods are: |
517 |
|
518 |
=over 4 |
519 |
|
520 |
=item cleartext |
521 |
|
522 |
This is simply the shared secret, lowercase-hex-encoded. This method is of |
523 |
course very insecure if TLS is not used (and not completely secure even |
524 |
if TLS is used), which is why this module will accept, but not generate, |
525 |
cleartext auth replies. |
526 |
|
527 |
=item hmac_md6_64_256 |
528 |
|
529 |
This method uses an MD6 HMAC with 64 bit blocksize and 256 bit hash, and |
530 |
requires a shared secret. It is the preferred auth method when a shared |
531 |
secret is available. |
532 |
|
533 |
First, the shared secret is hashed with MD6: |
534 |
|
535 |
key = MD6 (secret) |
536 |
|
537 |
This secret is then used to generate the "local auth reply", by taking |
538 |
the two local greeting lines and the two remote greeting lines (without |
539 |
line endings), appending \012 to all of them, concatenating them and |
540 |
calculating the MD6 HMAC with the key: |
541 |
|
542 |
lauth = HMAC_MD6 key, "lgreeting1\012lgreeting2\012rgreeting1\012rgreeting2\012" |
543 |
|
544 |
This authentication token is then lowercase-hex-encoded and sent to the |
545 |
other side. |
546 |
|
547 |
Then the remote auth reply is generated using the same method, but local |
548 |
and remote greeting lines swapped: |
549 |
|
550 |
rauth = HMAC_MD6 key, "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012" |
551 |
|
552 |
This is the token that is expected from the other side. |
553 |
|
554 |
=item tls_anon |
555 |
|
556 |
This type is only valid I<iff> TLS was enabled and the TLS handshake |
557 |
was successful. It has no authentication data, as the server/client |
558 |
certificate was successfully verified. |
559 |
|
560 |
This authentication type is somewhat insecure, as it allows a |
561 |
man-in-the-middle attacker to change some of the connection parameters |
562 |
(such as the framing format), although there is no known attack that |
563 |
exploits this in a way that is worse than just denying the service. |
564 |
|
565 |
By default, this implementation accepts but never generates this auth |
566 |
reply. |
567 |
|
568 |
=item tls_md6_64_256 |
569 |
|
570 |
This type is only valid I<iff> TLS was enabled and the TLS handshake was |
571 |
successful. |
572 |
|
573 |
This authentication type simply calculates: |
574 |
|
575 |
lauth = MD6 "rgreeting1\012rgreeting2\012lgreeting1\012lgreeting2\012" |
576 |
|
577 |
and lowercase-hex encodes the result and sends it as authentication |
578 |
data. No shared secret is required (authentication is done by TLS). The |
579 |
checksum exists only to make tinkering with the greeting hard. |
580 |
|
581 |
=back |
582 |
|
583 |
=item the authentication data |
584 |
|
585 |
The authentication data itself, usually base64 or hex-encoded data, see |
586 |
above. |
587 |
|
588 |
=item the framing protocol chosen |
589 |
|
590 |
This must be one of the framing protocols offered by the other side in the |
591 |
greeting. Each side must accept the choice of the other side, and generate |
592 |
packets in the format it chose itself. |
593 |
|
594 |
=back |
595 |
|
596 |
Example of an authentication reply: |
597 |
|
598 |
hmac_md6_64_256;363d5175df38bd9eaddd3f6ca18aa1c0c4aa22f0da245ac638d048398c26b8d3;json |
599 |
|
600 |
=head2 DATA PHASE |
601 |
|
602 |
After this, packets get exchanged using the chosen framing protocol. It is |
603 |
quite possible that both sides use a different framing protocol. |
604 |
|
605 |
=head2 FULL EXAMPLE |
606 |
|
607 |
This is an actual protocol dump of a handshake, followed by a single data |
608 |
packet. The greater than/less than lines indicate the direction of the |
609 |
transfer only. |
610 |
|
611 |
> aemp;0;anon/57Cs1CggVJjzYaQp13XXg4;tls_md6_64_256,hmac_md6_64_256,tls_anon,cleartext;json,storable;provider=AE-0.8;timeout=12;peeraddr=10.0.0.17:4040 |
612 |
> yLgdG1ov/02shVkVQer3wzeuywZK+oraTdEQBmIqWHaegxSGDG4g+HqogLQbvdypFOsoDWJ1Sh4ImV4DMhvUBwTK |
613 |
|
614 |
< aemp;0;ruth;tls_md6_64_256,hmac_md6_64_256,tls_anon,cleartext;json,storable;provider=AE-0.8;timeout=12;peeraddr=10.0.0.1:37108 |
615 |
< +xMQXP8ElfNmuvEhsmcp+s2wCJOuQAsPxSg3d2Ewhs6gBnJz+ypVdWJ/wAVrXqlIJfLeVS/CBy4gEGkyWHSuVb1L |
616 |
|
617 |
> hmac_md6_64_256;5ad913855742ae5a03a5aeb7eafa4c78629de136bed6acd73eea36c9e98df44a;json |
618 |
|
619 |
< hmac_md6_64_256;84cd590976f794914c2ca26dac3a207a57a6798b9171289c114de07cf0c20401;json |
620 |
< ["","AnyEvent::MP::_spawn","57Cs1CggVJjzYaQp13XXg4.c","AnyEvent::MP::Global::connect",0,"anon/57Cs1CggVJjzYaQp13XXg4"] |
621 |
... |
622 |
|
623 |
The shared secret in use was C<8ugxrtw6H5tKnfPWfaSr4HGhE8MoJXmzTT1BWq7sLutNcD0IbXprQlZjIbl7MBKoeklG3IEfY9GlJthC0pENzk>. |
624 |
|
625 |
=head2 MONITORING |
626 |
|
627 |
Monitoring the connection itself is transport-specific. For TCP, all |
628 |
connection monitoring is currently left to TCP retransmit time-outs |
629 |
on a busy link, and TCP keepalive (which should be enabled) for idle |
630 |
connections. |
631 |
|
632 |
This is not sufficient for listener-less nodes, however: they need |
633 |
to regularly send data (30 seconds, or the monitoring interval, is |
634 |
recommended), so TCP actively probes. |
635 |
|
636 |
Future implementations of AnyEvent::Transport might query the kernel TCP |
637 |
buffer after a write timeout occurs, and if it is non-empty, shut down the |
638 |
connections, but this is an area of future research :) |
639 |
|
640 |
=head2 NODE PROTOCOL |
641 |
|
642 |
The transport simply transfers messages, but to implement a full node, a |
643 |
special node port must exist that understands a number of requests. |
644 |
|
645 |
If you are interested in implementing this, drop us a note so we finish |
646 |
the documentation. |
647 |
|
648 |
=head1 SEE ALSO |
649 |
|
650 |
L<AnyEvent::MP>. |
651 |
|
652 |
=head1 AUTHOR |
653 |
|
654 |
Marc Lehmann <schmorp@schmorp.de> |
655 |
http://home.schmorp.de/ |
656 |
|
657 |
=cut |
658 |
|
659 |
1 |
660 |
|