Annotation of loncom/LondConnection.pm, revision 1.25
1.2 albertel 1: # This module defines and implements a class that represents
2: # a connection to a lond daemon.
3: #
1.25 ! albertel 4: # $Id: LondConnection.pm,v 1.24 2004/02/09 10:57:37 foxr Exp $
1.2 albertel 5: #
6: # Copyright Michigan State University Board of Trustees
7: #
8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
9: #
10: # LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
1.1 foxr 27: #
1.14 foxr 28:
1.1 foxr 29: package LondConnection;
30:
1.10 foxr 31: use strict;
1.1 foxr 32: use IO::Socket;
33: use IO::Socket::INET;
34: use IO::Handle;
35: use IO::File;
36: use Fcntl;
37: use POSIX;
38: use Crypt::IDEA;
1.14 foxr 39:
1.1 foxr 40:
1.12 foxr 41:
42:
43:
1.6 foxr 44: my $DebugLevel=0;
1.12 foxr 45: my %hostshash;
46: my %perlvar;
1.1 foxr 47:
1.14 foxr 48: #
1.16 foxr 49: # Set debugging level
50: #
51: sub SetDebug {
52: $DebugLevel = shift;
53: }
54:
55: #
1.14 foxr 56: # The config read is done in this way to support the read of
57: # the non-default configuration file in the
58: # event we are being used outside of loncapa.
59: #
60:
61: my $ConfigRead = 0;
62:
1.1 foxr 63: # Read the configuration file for apache to get the perl
64: # variable set.
65:
1.12 foxr 66: sub ReadConfig {
1.14 foxr 67: my $perlvarref = read_conf('loncapa.conf');
1.12 foxr 68: %perlvar = %{$perlvarref};
1.14 foxr 69: my $hoststab = read_hosts(
1.21 foxr 70: "$perlvar{lonTabDir}/hosts.tab") ||
1.14 foxr 71: die "Can't read host table!!";
1.12 foxr 72: %hostshash = %{$hoststab};
1.17 foxr 73: $ConfigRead = 1;
1.12 foxr 74:
75: }
76:
1.15 foxr 77: #
78: # Read a foreign configuration.
79: # This sub is intended for the cases where the package
80: # will be read from outside the LonCAPA environment, in that case
81: # the client will need to explicitly provide:
82: # - A file in hosts.tab format.
83: # - Some idea of the 'lonCAPA' name of the local host (for building
84: # the encryption key).
85: #
86: # Parameters:
87: # MyHost - Name of this host as far as LonCAPA is concerned.
88: # Filename - Name of a hosts.tab formatted file that will be used
89: # to build up the hosts table.
90: #
91: sub ReadForeignConfig {
92: my $MyHost = shift;
93: my $Filename = shift;
94:
1.17 foxr 95: &Debug(4, "ReadForeignConfig $MyHost $Filename\n");
96:
1.15 foxr 97: $perlvar{lonHostID} = $MyHost; # Rmember my host.
98: my $hosttab = read_hosts($Filename) ||
99: die "Can't read hosts table!!";
1.17 foxr 100: %hostshash = %{$hosttab};
101: if($DebugLevel > 3) {
102: foreach my $host (keys %hostshash) {
103: print "host $host => $hostshash{$host}\n";
104: }
105: }
106: $ConfigRead = 1;
1.1 foxr 107:
1.15 foxr 108: }
1.1 foxr 109:
110: sub Debug {
111: my $level = shift;
112: my $message = shift;
113: if ($level < $DebugLevel) {
114: print($message."\n");
115: }
116: }
1.3 albertel 117:
118: =pod
119:
120: =head2 Dump
121:
1.12 foxr 122: Dump the internal state of the object: For debugging purposes, to stderr.
1.3 albertel 123:
1.1 foxr 124: =cut
125:
126: sub Dump {
127: my $self = shift;
1.10 foxr 128: my $key;
129: my $value;
1.22 foxr 130: print STDERR "Dumping LondConnectionObject:\n";
1.1 foxr 131: while(($key, $value) = each %$self) {
1.22 foxr 132: print STDERR "$key -> $value\n";
1.1 foxr 133: }
1.23 foxr 134: print STDERR "-------------------------------\n";
1.1 foxr 135: }
136:
137: =pod
1.3 albertel 138:
139: Local function to do a state transition. If the state transition
140: callback is defined it is called with two parameters: the self and the
141: old state.
142:
1.1 foxr 143: =cut
1.3 albertel 144:
1.1 foxr 145: sub Transition {
146: my $self = shift;
147: my $newstate = shift;
148: my $oldstate = $self->{State};
149: $self->{State} = $newstate;
150: $self->{TimeoutRemaining} = $self->{TimeoutValue};
151: if($self->{TransitionCallback}) {
152: ($self->{TransitionCallback})->($self, $oldstate);
153: }
154: }
155:
1.3 albertel 156:
1.14 foxr 157:
1.1 foxr 158: =pod
1.3 albertel 159:
160: =head2 new
161:
162: Construct a new lond connection.
163:
164: Parameters (besides the class name) include:
165:
166: =item hostname
167:
168: host the remote lond is on. This host is a host in the hosts.tab file
169:
170: =item port
171:
172: port number the remote lond is listening on.
173:
1.1 foxr 174: =cut
1.3 albertel 175:
1.1 foxr 176: sub new {
177: my $class = shift; # class name.
178: my $Hostname = shift; # Name of host to connect to.
179: my $Port = shift; # Port to connect
1.14 foxr 180:
181: if (!$ConfigRead) {
182: ReadConfig();
183: $ConfigRead = 1;
184: }
1.1 foxr 185: &Debug(4,$class."::new( ".$Hostname.",".$Port.")\n");
186:
187: # The host must map to an entry in the hosts table:
188: # We connect to the dns host that corresponds to that
189: # system and use the hostname for the encryption key
190: # negotion. In the objec these become the Host and
191: # LoncapaHim fields of the object respectively.
192: #
193: if (!exists $hostshash{$Hostname}) {
1.16 foxr 194: &Debug(8, "No Such host $Hostname");
1.1 foxr 195: return undef; # No such host!!!
196: }
197: my @ConfigLine = @{$hostshash{$Hostname}};
198: my $DnsName = $ConfigLine[3]; # 4'th item is dns of host.
199: Debug(5, "Connecting to ".$DnsName);
200: # Now create the object...
201: my $self = { Host => $DnsName,
1.24 foxr 202: LoncapaHim => $Hostname,
203: Port => $Port,
204: State => "Initialized",
205: TransactionRequest => "",
206: TransactionReply => "",
207: InformReadable => 0,
208: InformWritable => 0,
209: TimeoutCallback => undef,
210: TransitionCallback => undef,
211: Timeoutable => 0,
212: TimeoutValue => 30,
213: TimeoutRemaining => 0,
214: CipherKey => "",
215: LondVersion => "Unknown",
216: Cipher => undef};
1.1 foxr 217: bless($self, $class);
218: unless ($self->{Socket} = IO::Socket::INET->new(PeerHost => $self->{Host},
1.25 ! albertel 219: PeerPort => $self->{Port},
! 220: Type => SOCK_STREAM,
! 221: Proto => "tcp",
! 222: Timeout => 3)) {
1.1 foxr 223: return undef; # Inidicates the socket could not be made.
224: }
225: #
226: # We're connected. Set the state, and the events we'll accept:
227: #
228: $self->Transition("Connected");
229: $self->{InformWritable} = 1; # When socket is writable we send init
1.9 foxr 230: $self->{Timeoutable} = 1; # Timeout allowed during startup negotiation.
1.1 foxr 231: $self->{TransactionRequest} = "init\n";
232:
233: #
234: # Set socket to nonblocking I/O.
235: #
236: my $socket = $self->{Socket};
1.10 foxr 237: my $flags = fcntl($socket->fileno, F_GETFL,0);
1.1 foxr 238: if($flags == -1) {
239: $socket->close;
240: return undef;
241: }
242: if(fcntl($socket, F_SETFL, $flags | O_NONBLOCK) == -1) {
243: $socket->close;
244: return undef;
245: }
246:
247: # return the object :
248:
249: return $self;
250: }
1.3 albertel 251:
1.1 foxr 252: =pod
1.3 albertel 253:
254: =head2 Readable
255:
256: This member should be called when the Socket becomes readable. Until
257: the read completes, action is state independet. Data are accepted into
258: the TransactionReply until a newline character is received. At that
259: time actionis state dependent:
260:
261: =item Connected
262:
263: in this case we received challenge, the state changes to
264: ChallengeReceived, and we initiate a send with the challenge response.
265:
266: =item ReceivingReply
267:
268: In this case a reply has been received for a transaction, the state
269: goes to Idle and we disable write and read notification.
270:
271: =item ChallengeReeived
272:
273: we just got what should be an ok\n and the connection can now handle
274: transactions.
1.1 foxr 275:
276: =cut
1.3 albertel 277:
1.1 foxr 278: sub Readable {
279: my $self = shift;
280: my $socket = $self->{Socket};
281: my $data = '';
282: my $rv = $socket->recv($data, POSIX::BUFSIZ, 0);
283: my $errno = $! + 0; # Force numeric context.
284:
1.8 foxr 285: unless (defined($rv) && length $data) {# Read failed,
1.1 foxr 286: if(($errno == POSIX::EWOULDBLOCK) ||
287: ($errno == POSIX::EAGAIN) ||
1.8 foxr 288: ($errno == POSIX::EINTR)) {
1.1 foxr 289: return 0;
290: }
291:
292: # Connection likely lost.
293: &Debug(4, "Connection lost");
294: $self->{TransactionRequest} = '';
295: $socket->close();
296: $self->Transition("Disconnected");
297: return -1;
298: }
299: # Append the data to the buffer. And figure out if the read is done:
300:
301: &Debug(9,"Received from host: ".$data);
302: $self->{TransactionReply} .= $data;
303: if($self->{TransactionReply} =~ /(.*\n)/) {
304: &Debug(8,"Readable End of line detected");
305: if ($self->{State} eq "Initialized") { # We received the challenge:
1.10 foxr 306: if($self->{TransactionReply} eq "refused\n") { # Remote doesn't have
1.1 foxr 307:
308: $self->Transition("Disconnected"); # in host tables.
309: $socket->close();
310: return -1;
311: }
1.25 ! albertel 312:
1.1 foxr 313: &Debug(8," Transition out of Initialized");
314: $self->{TransactionRequest} = $self->{TransactionReply};
315: $self->{InformWritable} = 1;
316: $self->{InformReadable} = 0;
317: $self->Transition("ChallengeReceived");
318: $self->{TimeoutRemaining} = $self->{TimeoutValue};
319: return 0;
1.25 ! albertel 320: } elsif ($self->{State} eq "ChallengeReplied") {
! 321: if($self->{TransactionReply} ne "ok\n") {
! 322: $self->Transition("Disconnected");
! 323: $socket->close();
! 324: return -1;
! 325: }
! 326: $self->Transition("RequestingVersion");
! 327: $self->{InformReadable} = 0;
! 328: $self->{InformWritable} = 1;
! 329: $self->{TransactionRequest} = "version\n";
! 330: return 0;
! 331: } elsif ($self->{State} eq "ReadingVersionString") {
! 332: $self->{LondVersion} = chomp($self->{TransactionReply});
! 333: $self->Transition("SetHost");
! 334: $self->{InformReadable} = 0;
! 335: $self->{InformWritable} = 1;
! 336: my $peer = $self->{LoncapaHim};
! 337: $self->{TransactionRequest}= "sethost:$peer\n";
! 338: return 0;
1.24 foxr 339: } elsif ($self->{State} eq "HostSet") { # should be ok.
1.25 ! albertel 340: if($self->{TransactionReply} ne "ok\n") {
! 341: $self->Transition("Disconnected");
! 342: $socket->close();
! 343: return -1;
! 344: }
! 345: $self->Transition("RequestingKey");
! 346: $self->{InformReadable} = 0;
! 347: $self->{InformWritable} = 1;
! 348: $self->{TransactionRequest} = "ekey\n";
! 349: return 0;
1.1 foxr 350: } elsif ($self->{State} eq "ReceivingKey") {
351: my $buildkey = $self->{TransactionReply};
352: my $key = $self->{LoncapaHim}.$perlvar{'lonHostID'};
353: $key=~tr/a-z/A-Z/;
354: $key=~tr/G-P/0-9/;
355: $key=~tr/Q-Z/0-9/;
356: $key=$key.$buildkey.$key.$buildkey.$key.$buildkey;
357: $key=substr($key,0,32);
358: my $cipherkey=pack("H32",$key);
359: $self->{Cipher} = new IDEA $cipherkey;
1.13 foxr 360: if($self->{Cipher} eq undef) {
1.1 foxr 361: $self->Transition("Disconnected");
362: $socket->close();
363: return -1;
364: } else {
365: $self->Transition("Idle");
366: $self->{InformWritable} = 0;
367: $self->{InformReadable} = 0;
368: $self->{Timeoutable} = 0;
369: return 0;
370: }
371: } elsif ($self->{State} eq "ReceivingReply") {
372:
373: # If the data are encrypted, decrypt first.
374:
375: my $answer = $self->{TransactionReply};
376: if($answer =~ /^enc\:/) {
377: $answer = $self->Decrypt($answer);
378: $self->{TransactionReply} = $answer;
379: }
380:
381: # finish the transaction
382:
383: $self->{InformWritable} = 0;
384: $self->{InformReadable} = 0;
385: $self->{Timeoutable} = 0;
386: $self->Transition("Idle");
387: return 0;
388: } elsif ($self->{State} eq "Disconnected") { # No connection.
389: return -1;
390: } else { # Internal error: Invalid state.
391: $self->Transition("Disconnected");
392: $socket->close();
393: return -1;
394: }
395: }
396:
397: return 0;
1.25 ! albertel 398:
1.1 foxr 399: }
400:
401:
402: =pod
1.3 albertel 403:
404: This member should be called when the Socket becomes writable.
405:
406: The action is state independent. An attempt is made to drain the
407: contents of the TransactionRequest member. Once this is drained, we
408: mark the object as waiting for readability.
1.1 foxr 409:
410: Returns 0 if successful, or -1 if not.
1.3 albertel 411:
1.1 foxr 412: =cut
1.25 ! albertel 413:
1.1 foxr 414: sub Writable {
415: my $self = shift; # Get reference to the object.
416: my $socket = $self->{Socket};
417: my $nwritten = $socket->send($self->{TransactionRequest}, 0);
418: my $errno = $! + 0;
419: unless (defined $nwritten) {
420: if($errno != POSIX::EINTR) {
421: $self->Transition("Disconnected");
422: return -1;
423: }
424:
425: }
1.10 foxr 426: if (($nwritten >= 0) ||
1.1 foxr 427: ($errno == POSIX::EWOULDBLOCK) ||
428: ($errno == POSIX::EAGAIN) ||
429: ($errno == POSIX::EINTR) ||
430: ($errno == 0)) {
431: substr($self->{TransactionRequest}, 0, $nwritten) = ""; # rmv written part
1.25 ! albertel 432: if(length $self->{TransactionRequest} == 0) {
! 433: $self->{InformWritable} = 0;
! 434: $self->{InformReadable} = 1;
! 435: $self->{TransactionReply} = '';
! 436: #
! 437: # Figure out the next state:
! 438: #
! 439: if($self->{State} eq "Connected") {
! 440: $self->Transition("Initialized");
! 441: } elsif($self->{State} eq "ChallengeReceived") {
! 442: $self->Transition("ChallengeReplied");
! 443: } elsif($self->{State} eq "RequestingVersion") {
! 444: $self->Transition("ReadingVersionString");
! 445: } elsif ($self->{State} eq "SetHost") {
! 446: $self->Transition("HostSet");
! 447: } elsif($self->{State} eq "RequestingKey") {
! 448: $self->Transition("ReceivingKey");
1.24 foxr 449: # $self->{InformWritable} = 0;
450: # $self->{InformReadable} = 1;
451: # $self->{TransactionReply} = '';
1.25 ! albertel 452: } elsif ($self->{State} eq "SendingRequest") {
! 453: $self->Transition("ReceivingReply");
! 454: $self->{TimeoutRemaining} = $self->{TimeoutValue};
! 455: } elsif ($self->{State} eq "Disconnected") {
! 456: return -1;
! 457: }
! 458: return 0;
! 459: }
! 460: } else { # The write failed (e.g. partner disconnected).
! 461: $self->Transition("Disconnected");
! 462: $socket->close();
! 463: return -1;
! 464: }
1.1 foxr 465: }
1.25 ! albertel 466:
1.1 foxr 467: =pod
1.3 albertel 468:
469: =head2 Tick
470:
1.1 foxr 471: Tick is called every time unit by the event framework. It
1.3 albertel 472:
473: =item 1 decrements the remaining timeout.
474:
475: =item 2 If the timeout is zero, calls TimedOut indicating that the current operation timed out.
1.1 foxr 476:
477: =cut
478:
479: sub Tick {
480: my $self = shift;
481: $self->{TimeoutRemaining}--;
482: if ($self->{TimeoutRemaining} < 0) {
483: $self->TimedOut();
484: }
485: }
1.3 albertel 486:
1.1 foxr 487: =pod
488:
1.3 albertel 489: =head2 TimedOut
490:
491: called on a timeout. If the timeout callback is defined, it is called
492: with $self as its parameters.
493:
494: =cut
495:
1.1 foxr 496: sub TimedOut {
497:
498: my $self = shift;
499: if($self->{TimeoutCallback}) {
500: my $callback = $self->{TimeoutCallback};
501: my @args = ( $self);
502: &$callback(@args);
503: }
504: }
1.3 albertel 505:
1.1 foxr 506: =pod
1.3 albertel 507:
508: =head2 InitiateTransaction
509:
510: Called to initiate a transaction. A transaction can only be initiated
511: when the object is idle... otherwise an error is returned. A
512: transaction consists of a request to the server that will have a
513: reply. This member sets the request data in the TransactionRequest
514: member, makes the state SendingRequest and sets the data to allow a
515: timout, and to request writability notification.
516:
1.1 foxr 517: =cut
1.3 albertel 518:
1.1 foxr 519: sub InitiateTransaction {
520: my $self = shift;
521: my $data = shift;
522:
1.4 foxr 523: Debug(1, "initiating transaction: ".$data);
1.1 foxr 524: if($self->{State} ne "Idle") {
1.4 foxr 525: Debug(0," .. but not idle here\n");
1.1 foxr 526: return -1; # Error indicator.
527: }
528: # if the transaction is to be encrypted encrypt the data:
529:
530: if($data =~ /^encrypt\:/) {
531: $data = $self->Encrypt($data);
532: }
533:
534: # Setup the trasaction
535:
536: $self->{TransactionRequest} = $data;
537: $self->{TransactionReply} = "";
538: $self->{InformWritable} = 1;
539: $self->{InformReadable} = 0;
540: $self->{Timeoutable} = 1;
541: $self->{TimeoutRemaining} = $self->{TimeoutValue};
542: $self->Transition("SendingRequest");
543: }
544:
545:
546: =pod
1.3 albertel 547:
548: =head2 SetStateTransitionCallback
549:
550: Sets a callback for state transitions. Returns a reference to any
551: prior established callback, or undef if there was none:
552:
1.1 foxr 553: =cut
1.3 albertel 554:
1.1 foxr 555: sub SetStateTransitionCallback {
556: my $self = shift;
557: my $oldCallback = $self->{TransitionCallback};
558: $self->{TransitionCallback} = shift;
559: return $oldCallback;
560: }
1.3 albertel 561:
1.1 foxr 562: =pod
1.3 albertel 563:
564: =head2 SetTimeoutCallback
565:
566: Sets the timeout callback. Returns a reference to any prior
567: established callback or undef if there was none.
568:
1.1 foxr 569: =cut
1.3 albertel 570:
1.1 foxr 571: sub SetTimeoutCallback {
572: my $self = shift;
573: my $callback = shift;
574: my $oldCallback = $self->{TimeoutCallback};
575: $self->{TimeoutCallback} = $callback;
576: return $oldCallback;
577: }
578:
579: =pod
1.3 albertel 580:
1.5 foxr 581: =head2 Shutdown:
582:
583: Shuts down the socket.
584:
585: =cut
586:
587: sub Shutdown {
588: my $self = shift;
589: my $socket = $self->GetSocket();
1.20 albertel 590: Debug(5,"socket is -$socket-");
591: if ($socket) {
592: # Ask lond to exit too. Non blocking so
593: # there is no cost for failure.
594: eval {
595: $socket->send("exit\n", 0);
596: $socket->shutdown(2);
597: }
598: }
1.5 foxr 599: }
600:
601: =pod
602:
1.3 albertel 603: =head2 GetState
604:
605: selector for the object state.
606:
1.1 foxr 607: =cut
1.3 albertel 608:
1.1 foxr 609: sub GetState {
610: my $self = shift;
611: return $self->{State};
612: }
1.3 albertel 613:
1.1 foxr 614: =pod
1.3 albertel 615:
616: =head2 GetSocket
617:
618: selector for the object socket.
619:
1.1 foxr 620: =cut
1.3 albertel 621:
1.1 foxr 622: sub GetSocket {
623: my $self = shift;
624: return $self->{Socket};
625: }
1.3 albertel 626:
1.5 foxr 627:
1.1 foxr 628: =pod
1.3 albertel 629:
630: =head2 WantReadable
631:
632: Return the state of the flag that indicates the object wants to be
633: called when readable.
634:
1.1 foxr 635: =cut
1.3 albertel 636:
1.1 foxr 637: sub WantReadable {
638: my $self = shift;
639:
640: return $self->{InformReadable};
641: }
1.3 albertel 642:
1.1 foxr 643: =pod
1.3 albertel 644:
645: =head2 WantWritable
646:
647: Return the state of the flag that indicates the object wants write
648: notification.
649:
1.1 foxr 650: =cut
1.3 albertel 651:
1.1 foxr 652: sub WantWritable {
653: my $self = shift;
654: return $self->{InformWritable};
655: }
1.3 albertel 656:
1.1 foxr 657: =pod
1.3 albertel 658:
659: =head2 WantTimeout
660:
661: return the state of the flag that indicates the object wants to be
662: informed of timeouts.
663:
1.1 foxr 664: =cut
1.3 albertel 665:
1.1 foxr 666: sub WantTimeout {
667: my $self = shift;
668: return $self->{Timeoutable};
669: }
670:
671: =pod
1.3 albertel 672:
673: =head2 GetReply
674:
675: Returns the reply from the last transaction.
676:
1.1 foxr 677: =cut
1.3 albertel 678:
1.1 foxr 679: sub GetReply {
680: my $self = shift;
681: return $self->{TransactionReply};
682: }
683:
684: =pod
1.3 albertel 685:
686: =head2 Encrypt
687:
688: Returns the encrypted version of the command string.
689:
690: The command input string is of the form:
691:
1.1 foxr 692: encrypt:command
1.3 albertel 693:
694: The output string can be directly sent to lond as it is of the form:
695:
1.1 foxr 696: enc:length:<encodedrequest>
1.3 albertel 697:
1.1 foxr 698: =cut
1.3 albertel 699:
1.1 foxr 700: sub Encrypt {
701: my $self = shift; # Reference to the object.
702: my $request = shift; # Text to send.
703:
704:
705: # Split the encrypt: off the request and figure out it's length.
706: # the cipher works in blocks of 8 bytes.
707:
708: my $cmd = $request;
709: $cmd =~ s/^encrypt\://; # strip off encrypt:
710: chomp($cmd); # strip off trailing \n
711: my $length=length($cmd); # Get the string length.
712: $cmd .= " "; # Pad with blanks so we can fill out a block.
713:
714: # encrypt the request in 8 byte chunks to create the encrypted
715: # output request.
716:
717: my $Encoded = '';
718: for(my $index = 0; $index <= $length; $index += 8) {
719: $Encoded .=
720: unpack("H16",
721: $self->{Cipher}->encrypt(substr($cmd,
722: $index, 8)));
723: }
724:
725: # Build up the answer as enc:length:$encrequest.
726:
727: $request = "enc:$length:$Encoded\n";
728: return $request;
729:
730:
731: }
1.3 albertel 732:
733: =pod
734:
735: =head2 Decrypt
736:
737: Decrypt a response from the server. The response is in the form:
738:
739: enc:<length>:<encrypted data>
740:
1.1 foxr 741: =cut
1.3 albertel 742:
1.1 foxr 743: sub Decrypt {
744: my $self = shift; # Recover reference to object
745: my $encrypted = shift; # This is the encrypted data.
746:
747: # Bust up the response into length, and encryptedstring:
748:
749: my ($enc, $length, $EncryptedString) = split(/:/,$encrypted);
750: chomp($EncryptedString);
751:
752: # Decode the data in 8 byte blocks. The string is encoded
753: # as hex digits so there are two characters per byte:
754:
1.10 foxr 755: my $decrypted = "";
1.1 foxr 756: for(my $index = 0; $index < length($EncryptedString);
757: $index += 16) {
758: $decrypted .= $self->{Cipher}->decrypt(
759: pack("H16",
760: substr($EncryptedString,
761: $index,
762: 16)));
763: }
764: # the answer may have trailing pads to fill out a block.
765: # $length tells us the actual length of the decrypted string:
766:
767: $decrypted = substr($decrypted, 0, $length);
768:
769: return $decrypted;
770:
771: }
772:
773: =pod
1.3 albertel 774:
775: =head2 GetHostIterator
1.1 foxr 776:
777: Returns a hash iterator to the host information. Each get from
778: this iterator returns a reference to an array that contains
779: information read from the hosts configuration file. Array elements
780: are used as follows:
781:
1.3 albertel 782: [0] - LonCapa host name.
783: [1] - LonCapa domain name.
784: [2] - Loncapa role (e.g. library or access).
785: [3] - DNS name server hostname.
1.11 foxr 786: [4] - IP address (result of e.g. nslookup [3]).
1.3 albertel 787: [5] - Maximum connection count.
788: [6] - Idle timeout for reducing connection count.
789: [7] - Minimum connection count.
1.1 foxr 790:
1.3 albertel 791: =cut
1.1 foxr 792:
793: sub GetHostIterator {
794:
795: return HashIterator->new(\%hostshash);
796: }
1.14 foxr 797:
798: ###########################################################
799: #
800: # The following is an unashamed kludge that is here to
801: # allow LondConnection to be used outside of the
802: # loncapa environment (e.g. by lonManage).
803: #
804: # This is a textual inclusion of pieces of the
805: # Configuration.pm module.
806: #
807:
808:
809: my $confdir='/etc/httpd/conf/';
810:
811: # ------------------- Subroutine read_conf: read LON-CAPA server configuration.
812: # This subroutine reads PerlSetVar values out of specified web server
813: # configuration files.
814: sub read_conf
815: {
816: my (@conf_files)=@_;
817: my %perlvar;
818: foreach my $filename (@conf_files,'loncapa_apache.conf')
819: {
1.21 foxr 820: if($DebugLevel > 3) {
821: print("Going to read $confdir.$filename\n");
822: }
1.14 foxr 823: open(CONFIG,'<'.$confdir.$filename) or
824: die("Can't read $confdir$filename");
825: while (my $configline=<CONFIG>)
826: {
827: if ($configline =~ /^[^\#]*PerlSetVar/)
828: {
829: my ($unused,$varname,$varvalue)=split(/\s+/,$configline);
830: chomp($varvalue);
831: $perlvar{$varname}=$varvalue;
832: }
833: }
834: close(CONFIG);
835: }
1.21 foxr 836: if($DebugLevel > 3) {
837: print "Dumping perlvar:\n";
838: foreach my $var (keys %perlvar) {
839: print "$var = $perlvar{$var}\n";
840: }
841: }
1.14 foxr 842: my $perlvarref=\%perlvar;
1.21 foxr 843: return $perlvarref;
844: }
1.14 foxr 845:
846: #---------------------- Subroutine read_hosts: Read a LON-CAPA hosts.tab
847: # formatted configuration file.
848: #
849: my $RequiredCount = 5; # Required item count in hosts.tab.
850: my $DefaultMaxCon = 5; # Default value for maximum connections.
851: my $DefaultIdle = 1000; # Default connection idle time in seconds.
852: my $DefaultMinCon = 0; # Default value for minimum connections.
853:
854: sub read_hosts {
855: my $Filename = shift;
856: my %HostsTab;
857:
1.16 foxr 858: open(CONFIG,'<'.$Filename) or die("Can't read $Filename");
1.14 foxr 859: while (my $line = <CONFIG>) {
860: if (!($line =~ /^\s*\#/)) {
861: my @items = split(/:/, $line);
862: if(scalar @items >= $RequiredCount) {
863: if (scalar @items == $RequiredCount) { # Only required items:
864: $items[$RequiredCount] = $DefaultMaxCon;
865: }
866: if(scalar @items == $RequiredCount + 1) { # up through maxcon.
867: $items[$RequiredCount+1] = $DefaultIdle;
868: }
869: if(scalar @items == $RequiredCount + 2) { # up through idle.
870: $items[$RequiredCount+2] = $DefaultMinCon;
871: }
872: {
873: my @list = @items; # probably not needed but I'm unsure of
874: # about the scope of item so...
875: $HostsTab{$list[0]} = \@list;
876: }
877: }
878: }
879: }
880: close(CONFIG);
881: my $hostref = \%HostsTab;
882: return ($hostref);
883: }
1.24 foxr 884: #
885: # Get the version of our peer. Note that this is only well
886: # defined if the state machine has hit the idle state at least
887: # once (well actually if it has transitioned out of
888: # ReadingVersionString The member data LondVersion is returned.
889: #
890: sub PeerVersion {
891: my $self = shift;
892:
893: return $self->{LondVersion};
894: }
1.1 foxr 895:
896: 1;
897:
898: =pod
1.3 albertel 899:
1.1 foxr 900: =head1 Theory
901:
1.3 albertel 902: The lond object is a state machine. It lives through the following states:
903:
904: =item Connected:
905:
906: a TCP connection has been formed, but the passkey has not yet been
907: negotiated.
908:
909: =item Initialized:
910:
911: "init" sent.
912:
913: =item ChallengeReceived:
914:
915: lond sent its challenge to us.
916:
917: =item ChallengeReplied:
918:
919: We replied to lond's challenge waiting for lond's ok.
920:
921: =item RequestingKey:
922:
923: We are requesting an encryption key.
924:
925: =item ReceivingKey:
926:
927: We are receiving an encryption key.
928:
929: =item Idle:
930:
931: Connection was negotiated but no requests are active.
932:
933: =item SendingRequest:
934:
935: A request is being sent to the peer.
936:
937: =item ReceivingReply:
938:
939: Waiting for an entire reply from the peer.
940:
941: =item Disconnected:
942:
943: For whatever reason, the connection was dropped.
944:
945: When we need to be writing data, we have a writable event. When we
946: need to be reading data, a readable event established. Events
947: dispatch through the class functions Readable and Writable, and the
948: watcher contains a reference to the associated object to allow object
949: context to be reached.
1.1 foxr 950:
951: =head2 Member data.
952:
1.3 albertel 953: =item Host
954:
955: Host socket is connected to.
956:
957: =item Port
958:
959: The port the remote lond is listening on.
960:
961: =item Socket
962:
963: Socket open on the connection.
964:
965: =item State
966:
967: The current state.
968:
969: =item TransactionRequest
970:
971: The request being transmitted.
972:
973: =item TransactionReply
974:
975: The reply being received from the transaction.
976:
977: =item InformReadable
978:
979: True if we want to be called when socket is readable.
980:
981: =item InformWritable
982:
983: True if we want to be informed if the socket is writable.
984:
985: =item Timeoutable
986:
987: True if the current operation is allowed to timeout.
988:
989: =item TimeoutValue
990:
991: Number of seconds in the timeout.
992:
993: =item TimeoutRemaining
994:
995: Number of seconds left in the timeout.
996:
997: =item CipherKey
998:
999: The key that was negotiated with the peer.
1000:
1001: =item Cipher
1002:
1003: The cipher obtained via the key.
1.1 foxr 1004:
1005:
1006: =head2 The following are callback like members:
1.3 albertel 1007:
1008: =item Tick:
1009:
1010: Called in response to a timer tick. Used to managed timeouts etc.
1011:
1012: =item Readable:
1013:
1014: Called when the socket becomes readable.
1015:
1016: =item Writable:
1017:
1018: Called when the socket becomes writable.
1019:
1020: =item TimedOut:
1021:
1022: Called when a timed operation timed out.
1023:
1.1 foxr 1024:
1025: =head2 The following are operational member functions.
1.3 albertel 1026:
1027: =item InitiateTransaction:
1028:
1029: Called to initiate a new transaction
1030:
1031: =item SetStateTransitionCallback:
1032:
1033: Called to establish a function that is called whenever the object goes
1034: through a state transition. This is used by The client to manage the
1035: work flow for the object.
1036:
1037: =item SetTimeoutCallback:
1038:
1039: Set a function to be called when a transaction times out. The
1040: function will be called with the object as its sole parameter.
1041:
1042: =item Encrypt:
1043:
1044: Encrypts a block of text according to the cipher negotiated with the
1045: peer (assumes the text is a command).
1046:
1047: =item Decrypt:
1048:
1049: Decrypts a block of text according to the cipher negotiated with the
1050: peer (assumes the block was a reply.
1.5 foxr 1051:
1052: =item Shutdown:
1053:
1054: Shuts off the socket.
1.1 foxr 1055:
1056: =head2 The following are selector member functions:
1057:
1.3 albertel 1058: =item GetState:
1059:
1060: Returns the current state
1061:
1062: =item GetSocket:
1063:
1064: Gets the socekt open on the connection to lond.
1065:
1066: =item WantReadable:
1067:
1068: true if the current state requires a readable event.
1069:
1070: =item WantWritable:
1071:
1072: true if the current state requires a writable event.
1073:
1074: =item WantTimeout:
1075:
1076: true if the current state requires timeout support.
1077:
1078: =item GetHostIterator:
1079:
1080: Returns an iterator into the host file hash.
1081:
1.1 foxr 1082: =cut
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/back.gif){kind=icon}
Return to LondConnection.pm CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [LON-CAPA] / loncom