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Revision: 1.25
Committed: Thu Aug 6 10:21:48 2009 UTC (14 years, 10 months ago) by root
Branch: MAIN
Changes since 1.24: +2 -2 lines
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File Contents

# Content
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 MIME::Base64 ();
29 use Storable ();
30 use JSON::XS ();
31
32 use Digest::MD6 ();
33 use Digest::HMAC_MD6 ();
34
35 use AE ();
36 use AnyEvent::Socket ();
37 use AnyEvent::Handle ();
38
39 use base Exporter::;
40
41 our $VERSION = '0.0';
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 => $peername, # for verification
113 ;
114
115 =cut
116
117 our @FRAMINGS = qw(json storable); # the framing types we accept and send, in order of preference
118 our @AUTH_SND = qw(hmac_md6_64_256); # auth types we send
119 our @AUTH_RCV = (@AUTH_SND, qw(cleartext)); # auth types we accept
120
121 #AnyEvent::Handle::register_write_type mp_record => sub {
122 #};
123
124 sub new {
125 my ($class, %arg) = @_;
126
127 my $self = bless \%arg, $class;
128
129 $self->{queue} = [];
130
131 {
132 Scalar::Util::weaken (my $self = $self);
133
134 $arg{secret} = AnyEvent::MP::Base::default_secret ()
135 unless exists $arg{secret};
136
137 $arg{timeout} = 30
138 unless exists $arg{timeout};
139
140 my $keepalive = (int $arg{timeout} * 0.75) || 1;
141
142 my $secret = $arg{secret};
143
144 if ($secret =~ /-----BEGIN RSA PRIVATE KEY-----.*-----END RSA PRIVATE KEY-----.*-----BEGIN CERTIFICATE-----.*-----END CERTIFICATE-----/s) {
145 # assume TLS mode
146 $arg{tls_ctx} = {
147 sslv2 => 0,
148 sslv3 => 0,
149 tlsv1 => 1,
150 verify => 1,
151 cert => $secret,
152 ca_cert => $secret,
153 verify_require_client_cert => 1,
154 };
155 }
156
157 $self->{hdl} = new AnyEvent::Handle
158 fh => delete $arg{fh},
159 autocork => 1,
160 no_delay => 1,
161 on_error => sub {
162 $self->error ($_[2]);
163 },
164 timeout => $AnyEvent::MP::Base::CONNECT_TIMEOUT,
165 peername => delete $arg{peername},
166 ;
167
168 my $greeting_kv = $self->{greeting} ||= {};
169
170 $self->{local_node} = $AnyEvent::MP::Base::NODE;
171
172 $greeting_kv->{"tls"} = "1.0" if $arg{tls_ctx};
173 $greeting_kv->{provider} = "AE-$VERSION";
174 $greeting_kv->{peeraddr} = AnyEvent::Socket::format_hostport $self->{peerhost}, $self->{peerport};
175 $greeting_kv->{maxidle} = $keepalive;
176
177 # send greeting
178 my $lgreeting1 = "aemp;$PROTOCOL_VERSION"
179 . ";$AnyEvent::MP::Base::UNIQ"
180 . ";$self->{local_node}"
181 . ";" . (join ",", @AUTH_RCV)
182 . ";" . (join ",", @FRAMINGS)
183 . (join "", map ";$_=$greeting_kv->{$_}", keys %$greeting_kv);
184
185 my $lgreeting2 = MIME::Base64::encode_base64 AnyEvent::MP::Base::nonce (33), "";
186
187 $self->{hdl}->push_write ("$lgreeting1\012$lgreeting2\012");
188
189 # expect greeting
190 $self->{hdl}->rbuf_max (4 * 1024);
191 $self->{hdl}->push_read (line => sub {
192 my $rgreeting1 = $_[1];
193
194 my ($aemp, $version, $uniq, $rnode, $auths, $framings, @kv) = split /;/, $rgreeting1;
195
196 if ($aemp ne "aemp") {
197 return $self->error ("unparsable greeting");
198 } elsif ($version != $PROTOCOL_VERSION) {
199 return $self->error ("version mismatch (we: $PROTOCOL_VERSION, they: $version)");
200 }
201
202 my $s_auth;
203 for my $auth_ (split /,/, $auths) {
204 if (grep $auth_ eq $_, @AUTH_SND) {
205 $s_auth = $auth_;
206 last;
207 }
208 }
209
210 defined $s_auth
211 or return $self->error ("$auths: no common auth type supported");
212
213 die unless $s_auth eq "hmac_md6_64_256"; # hardcoded atm.
214
215 my $s_framing;
216 for my $framing_ (split /,/, $framings) {
217 if (grep $framing_ eq $_, @FRAMINGS) {
218 $s_framing = $framing_;
219 last;
220 }
221 }
222
223 defined $s_framing
224 or return $self->error ("$framings: no common framing method supported");
225
226 $self->{remote_uniq} = $uniq;
227 $self->{remote_node} = $rnode;
228
229 $self->{remote_greeting} = {
230 map /^([^=]+)(?:=(.*))?/ ? ($1 => $2) : (),
231 @kv
232 };
233
234 # read nonce
235 $self->{hdl}->push_read (line => sub {
236 my $rgreeting2 = $_[1];
237
238 "$lgreeting1\012$lgreeting2" ne "$rgreeting1\012$rgreeting2" # echo attack?
239 or return $self->error ("authentication error, echo attack?");
240
241 my $key = Digest::MD6::md6 $secret;
242 my $lauth;
243
244 if ($self->{tls_ctx} and 1 == int $self->{remote_greeting}{tls}) {
245 $self->{tls} = $lgreeting2 lt $rgreeting2 ? "connect" : "accept";
246 $self->{hdl}->starttls ($self->{tls}, $self->{tls_ctx});
247 $s_auth = "tls";
248 $lauth = "";
249 } else {
250 # we currently only support hmac_md6_64_256
251 $lauth = Digest::HMAC_MD6::hmac_md6_hex $key, "$lgreeting1\012$lgreeting2\012$rgreeting1\012$rgreeting2\012", 64, 256;
252 }
253
254 $self->{hdl}->push_write ("$s_auth;$lauth;$s_framing\012");
255
256 # read the authentication response
257 $self->{hdl}->push_read (line => sub {
258 my ($hdl, $rline) = @_;
259
260 my ($auth_method, $rauth2, $r_framing) = split /;/, $rline;
261
262 my $rauth =
263 $auth_method eq "hmac_md6_64_256" ? Digest::HMAC_MD6::hmac_md6_hex $key, "$rgreeting1\012$rgreeting2\012$lgreeting1\012$lgreeting2\012", 64, 256
264 : $auth_method eq "cleartext" ? unpack "H*", $secret
265 : $auth_method eq "tls" ? ($self->{tls} ? "" : "\012\012") # \012\012 never matches
266 : return $self->error ("$auth_method: fatal, selected unsupported auth method");
267
268 if ($rauth2 ne $rauth) {
269 return $self->error ("authentication failure/shared secret mismatch");
270 }
271
272 $self->{s_framing} = $s_framing;
273
274 $hdl->rbuf_max (undef);
275 my $queue = delete $self->{queue}; # we are connected
276
277 $self->{hdl}->timeout ($self->{remote_greeting}{keepalive} + 5)
278 if $self->{remote_greeting}{keepalive};
279
280 $self->connected;
281
282 my $src_node = $self->{node};
283
284 $self->send ($_)
285 for @$queue;
286
287 my $rmsg; $rmsg = sub {
288 $_[0]->push_read ($r_framing => $rmsg);
289
290 local $AnyEvent::MP::Base::SRCNODE = $src_node;
291 AnyEvent::MP::Base::_inject (@{ $_[1] });
292 };
293 $hdl->push_read ($r_framing => $rmsg);
294 });
295 });
296 });
297 }
298
299 $self
300 }
301
302 sub error {
303 my ($self, $msg) = @_;
304
305 if ($self->{node} && $self->{node}{transport} == $self) {
306 #TODO: store error, but do not instantly fail
307 $self->{node}->fail (transport_error => $self->{node}{noderef}, $msg);
308 $self->{node}->clr_transport;
309 }
310 $AnyEvent::MP::Base::WARN->("$self->{peerhost}:$self->{peerport}: $msg");
311 $self->destroy;
312 }
313
314 sub connected {
315 my ($self) = @_;
316
317 if (ref $AnyEvent::MP::Base::SLAVE) {
318 # first connect with a master node
319 my $via = $self->{remote_node};
320 $via =~ s/,/!/g;
321 $AnyEvent::MP::Base::NODE .= "\@$via";
322 $AnyEvent::MP::Base::NODE{$AnyEvent::MP::Base::NODE} = $AnyEvent::MP::Base::NODE{""};
323 $AnyEvent::MP::Base::SLAVE->();
324 }
325
326 if ($self->{local_node} ne $AnyEvent::MP::Base::NODE) {
327 # node changed its name since first greeting
328 $self->send (["", iam => $AnyEvent::MP::Base::NODE]);
329 }
330
331 my $node = AnyEvent::MP::Base::add_node ($self->{remote_node});
332 Scalar::Util::weaken ($self->{node} = $node);
333 $node->set_transport ($self);
334 }
335
336 sub send {
337 $_[0]{hdl}->push_write ($_[0]{s_framing} => $_[1]);
338 }
339
340 sub destroy {
341 my ($self) = @_;
342
343 $self->{hdl}->destroy
344 if $self->{hdl};
345 }
346
347 sub DESTROY {
348 my ($self) = @_;
349
350 $self->destroy;
351 }
352
353 =back
354
355 =head1 PROTOCOL
356
357 The protocol is relatively simple, and consists of three phases which are
358 symmetrical for both sides: greeting (followed by optionally switching to
359 TLS mode), authentication and packet exchange.
360
361 the protocol is designed to allow both full-text and binary streams.
362
363 The greeting consists of two text lines that are ended by either an ASCII
364 CR LF pair, or a single ASCII LF (recommended).
365
366 =head2 GREETING
367
368 All the lines until after authentication must not exceed 4kb in length,
369 including delimiter. Afterwards there is no limit on the packet size that
370 can be received.
371
372 =head3 First Greeting Line
373
374 Example:
375
376 aemp;0;fec.4a7720fc;127.0.0.1:1235,[::1]:1235;hmac_md6_64_256;json,storable;provider=AE-0.0
377
378 The first line contains strings separated (not ended) by C<;>
379 characters. The first even ixtrings are fixed by the protocol, the
380 remaining strings are C<KEY=VALUE> pairs. None of them may contain C<;>
381 characters themselves.
382
383 The fixed strings are:
384
385 =over 4
386
387 =item protocol identification
388
389 The constant C<aemp> to identify the protocol.
390
391 =item protocol version
392
393 The protocol version supported by this end, currently C<0>. If the
394 versions don't match then no communication is possible. Minor extensions
395 are supposed to be handled through additional key-value pairs.
396
397 =item a token uniquely identifying the current node instance
398
399 This is a string that must change between restarts. It usually contains
400 things like the current time, the (OS) process id or similar values, but
401 no meaning of the contents are assumed.
402
403 =item the node endpoint descriptors
404
405 for public nodes, this is a comma-separated list of protocol endpoints,
406 i.e., the noderef. For slave nodes, this is a unique identifier.
407
408 =item the acceptable authentication methods
409
410 A comma-separated list of authentication methods supported by the
411 node. Note that AnyEvent::MP supports a C<hex_secret> authentication
412 method that accepts a cleartext password (hex-encoded), but will not use
413 this auth method itself.
414
415 The receiving side should choose the first auth method it supports.
416
417 =item the acceptable framing formats
418
419 A comma-separated list of packet encoding/framign formats understood. The
420 receiving side should choose the first framing format it supports for
421 sending packets (which might be different from the format it has to accept).
422
423 =back
424
425 The remaining arguments are C<KEY=VALUE> pairs. The following key-value
426 pairs are known at this time:
427
428 =over 4
429
430 =item provider=<module-version>
431
432 The software provider for this implementation. For AnyEvent::MP, this is
433 C<AE-0.0> or whatever version it currently is at.
434
435 =item peeraddr=<host>:<port>
436
437 The peer address (socket address of the other side) as seen locally, in the same format
438 as noderef endpoints.
439
440 =item tls=<major>.<minor>
441
442 Indicates that the other side supports TLS (version should be 1.0) and
443 wishes to do a TLS handshake.
444
445 =item maxidle=<seconds>
446
447 The maximum amount of time the node will not sent data, i.e., idle. This
448 can be used to close the conenction when no data has been received for a
449 too-long time (say, maxidle + 5 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
559 This is an actual protocol dump of a handshake, followed by a single data
560 packet. The greater than/less than lines indicate the direction of the
561 transfer only.
562
563 > 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
564 > sRG8bbc4TDbkpvH8FTP4HBs87OhepH6VuApoZqXXskuG
565 < 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
566 < dCEUcL/LJVSTJcx8byEsOzrwhzJYOq+L3YcopA5T6EAo
567 > hmac_md6_64_256;9513d4b258975accfcb2ab7532b83690e9c119a502c612203332a591c7237788;json
568 < hmac_md6_64_256;0298d6ba2240faabb2b2e881cf86b97d70a113ca74a87dc006f9f1e9d3010f90;json
569 > ["","lookup","pinger","10.0.0.1:4040#nndKd+gn.a","resolved"]
570
571 =head1 SEE ALSO
572
573 L<AnyEvent>.
574
575 =head1 AUTHOR
576
577 Marc Lehmann <schmorp@schmorp.de>
578 http://home.schmorp.de/
579
580 =cut
581
582 1
583