Annotation of loncom/loncnew, revision 1.8
1.1 foxr 1: #!/usr/bin/perl
1.2 albertel 2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
1.8 ! foxr 5: # $Id: loncnew,v 1.7 2003/06/03 01:59:39 foxr Exp $
1.2 albertel 6: #
7: # Copyright Michigan State University Board of Trustees
8: #
9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
10: #
11: # LON-CAPA is free software; you can redistribute it and/or modify
12: # it under the terms of the GNU General Public License as published by
13: # the Free Software Foundation; either version 2 of the License, or
14: # (at your option) any later version.
15: #
16: # LON-CAPA is distributed in the hope that it will be useful,
17: # but WITHOUT ANY WARRANTY; without even the implied warranty of
18: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19: # GNU General Public License for more details.
20: #
21: # You should have received a copy of the GNU General Public License
22: # along with LON-CAPA; if not, write to the Free Software
23: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24: #
25: # /home/httpd/html/adm/gpl.txt
26: #
27: # http://www.lon-capa.org/
28: #
1.1 foxr 29: #
30: # new lonc handles n requestors spread out bver m connections to londs.
31: # This module is based on the Event class.
32: # Development iterations:
33: # - Setup basic event loop. (done)
34: # - Add timer dispatch. (done)
35: # - Add ability to accept lonc UNIX domain sockets. (done)
36: # - Add ability to create/negotiate lond connections (done).
1.7 foxr 37: # - Add general logic for dispatching requests and timeouts. (done).
38: # - Add support for the lonc/lond requests. (done).
1.1 foxr 39: # - Add logging/status monitoring.
40: # - Add Signal handling - HUP restarts. USR1 status report.
1.7 foxr 41: # - Add Configuration file I/O (done).
1.1 foxr 42: # - Add management/status request interface.
1.8 ! foxr 43: # - Add deferred request capability. (done)
1.7 foxr 44: #
45:
46: # Change log:
1.8 ! foxr 47: # $Log: loncnew,v $
! 48: # Revision 1.7 2003/06/03 01:59:39 foxr
! 49: # complete coding to support deferred transactions.
! 50: #
1.7 foxr 51: #
1.1 foxr 52:
53: use lib "/home/httpd/lib/perl/";
54: use lib "/home/foxr/newloncapa/types";
55: use Event qw(:DEFAULT );
56: use POSIX qw(:signal_h);
57: use IO::Socket;
58: use IO::Socket::INET;
59: use IO::Socket::UNIX;
1.6 foxr 60: use IO::Handle;
1.1 foxr 61: use Socket;
62: use Crypt::IDEA;
63: use LONCAPA::Queue;
64: use LONCAPA::Stack;
65: use LONCAPA::LondConnection;
1.7 foxr 66: use LONCAPA::LondTransaction;
1.1 foxr 67: use LONCAPA::Configuration;
68: use LONCAPA::HashIterator;
69:
70: print "Loncnew starting\n";
71:
72: #
73: # Disable all signals we might receive from outside for now.
74: #
75: $SIG{QUIT} = IGNORE;
76: $SIG{HUP} = IGNORE;
77: $SIG{USR1} = IGNORE;
78: $SIG{INT} = IGNORE;
79: $SIG{CHLD} = IGNORE;
80: $SIG{__DIE__} = IGNORE;
81:
82:
83: # Read the httpd configuration file to get perl variables
84: # normally set in apache modules:
85:
86: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
87: my %perlvar = %{$perlvarref};
88:
89: #
90: # parent and shared variables.
91:
92: my %ChildHash; # by pid -> host.
93:
94:
95: my $MaxConnectionCount = 5; # Will get from config later.
96: my $ClientConnection = 0; # Uniquifier for client events.
97:
1.8 ! foxr 98: my $DebugLevel = 2;
1.1 foxr 99: my $IdleTimeout= 3600; # Wait an hour before pruning connections.
100:
101: #
102: # The variables below are only used by the child processes.
103: #
104: my $RemoteHost; # Name of host child is talking to.
105: my $UnixSocketDir= "/home/httpd/sockets";
106: my $IdleConnections = Stack->new(); # Set of idle connections
107: my %ActiveConnections; # Connections to the remote lond.
1.7 foxr 108: my %ActiveTransactions; # LondTransactions in flight.
1.1 foxr 109: my %ActiveClients; # Serial numbers of active clients by socket.
110: my $WorkQueue = Queue->new(); # Queue of pending transactions.
1.7 foxr 111: # my $ClientQueue = Queue->new(); # Queue of clients causing xactinos.
1.1 foxr 112: my $ConnectionCount = 0;
1.4 foxr 113: my $IdleSeconds = 0; # Number of seconds idle.
1.1 foxr 114:
115: #
1.6 foxr 116: # This disconnected socket makes posible a bit more regular
117: # code when processing delayed requests:
118: #
119: my $NullSocket = IO::Socket->new();
120:
121: #
1.3 albertel 122:
1.1 foxr 123: =pod
1.3 albertel 124:
125: =head2 GetPeerName
126:
127: Returns the name of the host that a socket object is connected to.
128:
1.1 foxr 129: =cut
130:
131: sub GetPeername {
132: my $connection = shift;
133: my $AdrFamily = shift;
134: my $peer = $connection->peername();
135: my $peerport;
136: my $peerip;
137: if($AdrFamily == AF_INET) {
138: ($peerport, $peerip) = sockaddr_in($peer);
139: my $peername = gethostbyaddr($iaddr, $AdrFamily);
140: return $peername;
141: } elsif ($AdrFamily == AF_UNIX) {
142: my $peerfile;
143: ($peerfile) = sockaddr_un($peer);
144: return $peerfile;
145: }
146: }
147: #----------------------------- Timer management ------------------------
148: =pod
1.3 albertel 149:
1.1 foxr 150: =head2 Debug
1.3 albertel 151:
152: Invoked to issue a debug message.
153:
1.1 foxr 154: =cut
1.3 albertel 155:
1.1 foxr 156: sub Debug {
157: my $level = shift;
158: my $message = shift;
159: if ($level <= $DebugLevel) {
160: print $message." host = ".$RemoteHost."\n";
161: }
162: }
163:
164: sub SocketDump {
165: my $level = shift;
166: my $socket= shift;
167: if($level <= $DebugLevel) {
168: $socket->Dump();
169: }
170: }
1.3 albertel 171:
1.1 foxr 172: =pod
1.3 albertel 173:
1.5 foxr 174: =head2 ShowStatus
175:
176: Place some text as our pid status.
177:
178: =cut
179: sub ShowStatus {
180: my $status = shift;
181: $0 = "lonc: ".$status;
182: }
183:
184: =pod
185:
1.1 foxr 186: =head2 Tick
1.3 albertel 187:
188: Invoked each timer tick.
189:
1.1 foxr 190: =cut
191:
1.5 foxr 192:
1.1 foxr 193: sub Tick {
194: my $client;
1.5 foxr 195: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount);
1.1 foxr 196: Debug(6, "Tick");
197: Debug(6, " Current connection count: ".$ConnectionCount);
198: foreach $client (keys %ActiveClients) {
199: Debug(7, " Have client: with id: ".$ActiveClients{$client});
200: }
1.4 foxr 201: # Is it time to prune connection count:
202:
203:
204: if($IdleConnections->Count() &&
205: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
206: $IdleSeconds++;
207: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
208: $Socket = $IdleConnections->pop();
1.6 foxr 209: KillSocket($Socket);
1.4 foxr 210: }
211: } else {
212: $IdleSeconds = 0; # Reset idle count if not idle.
213: }
1.5 foxr 214:
215: # Do we have work in the queue, but no connections to service them?
216: # If so, try to make some new connections to get things going again.
217: #
218:
219: my $Requests = $WorkQueue->Count();
220: if (($ConnectionCount == 0) && ($Requests > 0)) {
221: my $Connections = ($Requests <= $MaxConnectionCount) ?
222: $Requests : $MaxConnectionCount;
223: Debug(1,"Work but no connections, starting ".$Connections." of them");
224: for ($i =0; $i < $Connections; $i++) {
225: MakeLondConnection();
226: }
227:
228: }
1.1 foxr 229: }
230:
231: =pod
1.3 albertel 232:
1.1 foxr 233: =head2 SetupTimer
234:
1.3 albertel 235: Sets up a 1 per sec recurring timer event. The event handler is used to:
1.1 foxr 236:
1.3 albertel 237: =item
238:
239: Trigger timeouts on communications along active sockets.
240:
241: =item
242:
243: Trigger disconnections of idle sockets.
1.1 foxr 244:
245: =cut
246:
247: sub SetupTimer {
248: Debug(6, "SetupTimer");
249: Event->timer(interval => 1, debug => 1, cb => \&Tick );
250: }
1.3 albertel 251:
1.1 foxr 252: =pod
1.3 albertel 253:
1.1 foxr 254: =head2 ServerToIdle
1.3 albertel 255:
256: This function is called when a connection to the server is
257: ready for more work.
258:
259: If there is work in the Work queue the top element is dequeued
1.1 foxr 260: and the connection will start to work on it. If the work queue is
261: empty, the connection is pushed on the idle connection stack where
262: it will either get another work unit, or alternatively, if it sits there
263: long enough, it will be shut down and released.
264:
1.3 albertel 265: =cut
1.1 foxr 266:
267: sub ServerToIdle {
268: my $Socket = shift; # Get the socket.
1.7 foxr 269: delete($ActiveTransactions{$Socket}); # Server has no transaction
1.1 foxr 270:
271: &Debug(6, "Server to idle");
272:
273: # If there's work to do, start the transaction:
274:
1.7 foxr 275: $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
1.1 foxr 276: unless($reqdata eq undef) {
1.7 foxr 277: Debug(9, "Queue gave request data: ".$reqdata->getRequest());
278: &StartRequest($Socket, $reqdata);
1.8 ! foxr 279:
1.1 foxr 280: } else {
281:
282: # There's no work waiting, so push the server to idle list.
283: &Debug(8, "No new work requests, server connection going idle");
284: $IdleConnections->push($Socket);
285: }
286: }
1.3 albertel 287:
1.1 foxr 288: =pod
1.3 albertel 289:
1.1 foxr 290: =head2 ClientWritable
1.3 albertel 291:
292: Event callback for when a client socket is writable.
293:
294: This callback is established when a transaction reponse is
295: avaiable from lond. The response is forwarded to the unix socket
296: as it becomes writable in this sub.
297:
1.1 foxr 298: Parameters:
299:
1.3 albertel 300: =item Event
301:
302: The event that has been triggered. Event->w->data is
303: the data and Event->w->fd is the socket to write.
1.1 foxr 304:
305: =cut
1.3 albertel 306:
1.1 foxr 307: sub ClientWritable {
308: my $Event = shift;
309: my $Watcher = $Event->w;
310: my $Data = $Watcher->data;
311: my $Socket = $Watcher->fd;
312:
313: # Try to send the data:
314:
315: &Debug(6, "ClientWritable writing".$Data);
316: &Debug(9, "Socket is: ".$Socket);
317:
1.6 foxr 318: if($Socket->connected) {
319: my $result = $Socket->send($Data, 0);
320:
321: # $result undefined: the write failed.
322: # otherwise $result is the number of bytes written.
323: # Remove that preceding string from the data.
324: # If the resulting data is empty, destroy the watcher
325: # and set up a read event handler to accept the next
326: # request.
327:
328: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
329: if(defined($result)) {
330: &Debug(9, "send result was defined");
331: if($result == length($Data)) { # Entire string sent.
332: &Debug(9, "ClientWritable data all written");
333: $Watcher->cancel();
334: #
335: # Set up to read next request from socket:
336:
337: my $descr = sprintf("Connection to lonc client %d",
338: $ActiveClients{$Socket});
339: Event->io(cb => \&ClientRequest,
340: poll => 'r',
341: desc => $descr,
342: data => "",
343: fd => $Socket);
344:
345: } else { # Partial string sent.
346: $Watcher->data(substr($Data, $result));
347: }
348:
349: } else { # Error of some sort...
350:
351: # Some errnos are possible:
352: my $errno = $!;
353: if($errno == POSIX::EWOULDBLOCK ||
354: $errno == POSIX::EAGAIN ||
355: $errno == POSIX::EINTR) {
356: # No action taken?
357: } else { # Unanticipated errno.
358: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
359: $Watcher->cancel; # Stop the watcher.
360: $Socket->shutdown(2); # Kill connection
361: $Socket->close(); # Close the socket.
362: }
1.1 foxr 363:
364: }
1.6 foxr 365: } else {
366: $Watcher->cancel(); # A delayed request...just cancel.
1.1 foxr 367: }
368: }
369:
370: =pod
1.3 albertel 371:
1.1 foxr 372: =head2 CompleteTransaction
1.3 albertel 373:
374: Called when the reply data has been received for a lond
1.1 foxr 375: transaction. The reply data must now be sent to the
376: ultimate client on the other end of the Unix socket. This is
377: done by setting up a writable event for the socket with the
378: data the reply data.
1.3 albertel 379:
1.1 foxr 380: Parameters:
1.3 albertel 381:
382: =item Socket
383:
384: Socket on which the lond transaction occured. This is a
385: LondConnection. The data received is in the TransactionReply member.
386:
1.7 foxr 387: =item Transaction
1.3 albertel 388:
1.7 foxr 389: The transaction that is being completed.
1.1 foxr 390:
391: =cut
1.3 albertel 392:
1.1 foxr 393: sub CompleteTransaction {
394: &Debug(6,"Complete transaction");
395: my $Socket = shift;
1.7 foxr 396: my $Transaction = shift;
1.1 foxr 397:
1.7 foxr 398: if (!$Transaction->isDeferred()) { # Normal transaction
399: my $data = $Socket->GetReply(); # Data to send.
400: StartClientReply($Transaction, $data);
401: } else { # Delete deferred transaction file.
1.8 ! foxr 402: &Debug(4, "Deferred transaction complete: ".$Transaction->getFile().
! 403: " request: ".$Transaction->getRequest().
! 404: " answer: ".$Socket->GetReply());
1.7 foxr 405: unlink $Transaction->getFile();
406: }
1.6 foxr 407: }
408: =pod
409: =head1 StartClientReply
410:
411: Initiates a reply to a client where the reply data is a parameter.
412:
1.7 foxr 413: =head2 parameters:
414:
415: =item Transaction
416:
417: The transaction for which we are responding to the client.
418:
419: =item data
420:
421: The data to send to apached client.
422:
1.6 foxr 423: =cut
424: sub StartClientReply {
1.7 foxr 425: my $Transaction = shift;
1.6 foxr 426: my $data = shift;
1.1 foxr 427:
1.7 foxr 428: my $Client = $Transaction->getClient();
429:
1.1 foxr 430: &Debug(8," Reply was: ".$data);
431: my $Serial = $ActiveClients{$Client};
432: my $desc = sprintf("Connection to lonc client %d",
1.6 foxr 433:
1.1 foxr 434: $Serial);
435: Event->io(fd => $Client,
436: poll => "w",
437: desc => $desc,
438: cb => \&ClientWritable,
439: data => $data);
440: }
1.4 foxr 441: =pod
442: =head2 FailTransaction
443:
444: Finishes a transaction with failure because the associated lond socket
1.7 foxr 445: disconnected. There are two possibilities:
446: - The transaction is deferred: in which case we just quietly
447: delete the transaction since there is no client connection.
448: - The transaction is 'live' in which case we initiate the sending
449: of "con_lost" to the client.
450:
451: Deleting the transaction means killing it from the
452: %ActiveTransactions hash.
1.4 foxr 453:
454: Parameters:
455:
456: =item client
457:
1.7 foxr 458: The LondTransaction we are failing.
459:
1.4 foxr 460: =cut
461:
462: sub FailTransaction {
1.7 foxr 463: my $transaction = shift;
464: my $Lond = $transaction->getServer();
465: if (!$client->isDeferred()) { # If the transaction is deferred we'll get to it.
466: my $client = $transcation->getClient();
467: StartClientReply($client, "con_lost");
468: }
469: # not needed, done elsewhere if active.
470: # delete $ActiveTransactions{$Lond};
1.4 foxr 471:
472: }
473:
474: =pod
1.6 foxr 475: =head1 EmptyQueue
1.7 foxr 476:
1.6 foxr 477: Fails all items in the work queue with con_lost.
1.7 foxr 478: Note that each item in the work queue is a transaction.
479:
1.6 foxr 480: =cut
481: sub EmptyQueue {
482: while($WorkQueue->Count()) {
1.7 foxr 483: my $request = $Workqueue->dequeue(); # This is a transaction
484: FailTransaction($request);
1.6 foxr 485: }
486: }
487:
488: =pod
1.4 foxr 489:
490: =head2 KillSocket
491:
492: Destroys a socket. This function can be called either when a socket
493: has died of 'natural' causes or because a socket needs to be pruned due to
494: idleness. If the socket has died naturally, if there are no longer any
495: live connections a new connection is created (in case there are transactions
496: in the queue). If the socket has been pruned, it is never re-created.
497:
498: Parameters:
1.1 foxr 499:
1.4 foxr 500: =item Socket
501:
502: The socket to kill off.
503:
504: =item Restart
505:
506: nonzero if we are allowed to create a new connection.
507:
508:
509: =cut
510: sub KillSocket {
511: my $Socket = shift;
512:
1.7 foxr 513: # If the socket came from the active connection set,
514: # delete its transaction... note that FailTransaction should
515: # already have been called!!!
516: # otherwise it came from the idle set.
517: #
1.4 foxr 518:
519: if(exists($ActiveTransactions{$Socket})) {
520: delete ($ActiveTransactions{$Socket});
521: }
522: if(exists($ActiveConnections{$Socket})) {
523: delete($ActiveConnections{$Socket});
524: }
525: $ConnectionCount--;
1.6 foxr 526:
527: # If the connection count has gone to zero and there is work in the
528: # work queue, the work all gets failed with con_lost.
529: #
530: if($ConnectionCount == 0) {
531: EmptyQueue;
1.4 foxr 532: }
533: }
1.1 foxr 534:
535: =pod
1.3 albertel 536:
1.1 foxr 537: =head2 LondReadable
1.3 albertel 538:
1.1 foxr 539: This function is called whenever a lond connection
540: is readable. The action is state dependent:
541:
1.3 albertel 542: =head3 State=Initialized
543:
544: We''re waiting for the challenge, this is a no-op until the
1.1 foxr 545: state changes.
1.3 albertel 546:
1.1 foxr 547: =head3 State=Challenged
1.3 albertel 548:
549: The challenge has arrived we need to transition to Writable.
1.1 foxr 550: The connection must echo the challenge back.
1.3 albertel 551:
1.1 foxr 552: =head3 State=ChallengeReplied
1.3 albertel 553:
554: The challenge has been replied to. The we are receiveing the
1.1 foxr 555: 'ok' from the partner.
1.3 albertel 556:
1.1 foxr 557: =head3 State=RequestingKey
1.3 albertel 558:
559: The ok has been received and we need to send the request for
1.1 foxr 560: an encryption key. Transition to writable for that.
1.3 albertel 561:
1.1 foxr 562: =head3 State=ReceivingKey
1.3 albertel 563:
564: The the key has been requested, now we are reading the new key.
565:
1.1 foxr 566: =head3 State=Idle
1.3 albertel 567:
568: The encryption key has been negotiated or we have finished
1.1 foxr 569: reading data from the a transaction. If the callback data has
570: a client as well as the socket iformation, then we are
571: doing a transaction and the data received is relayed to the client
572: before the socket is put on the idle list.
1.3 albertel 573:
1.1 foxr 574: =head3 State=SendingRequest
1.3 albertel 575:
576: I do not think this state can be received here, but if it is,
1.1 foxr 577: the appropriate thing to do is to transition to writable, and send
578: the request.
1.3 albertel 579:
1.1 foxr 580: =head3 State=ReceivingReply
1.3 albertel 581:
582: We finished sending the request to the server and now transition
1.1 foxr 583: to readable to receive the reply.
584:
585: The parameter to this function are:
1.3 albertel 586:
1.1 foxr 587: The event. Implicit in this is the watcher and its data. The data
588: contains at least the lond connection object and, if a
589: transaction is in progress, the socket attached to the local client.
590:
1.3 albertel 591: =cut
1.1 foxr 592:
593: sub LondReadable {
1.8 ! foxr 594:
1.1 foxr 595: my $Event = shift;
596: my $Watcher = $Event->w;
597: my $Socket = $Watcher->data;
598: my $client = undef;
599:
1.8 ! foxr 600: &Debug(6,"LondReadable called state = ".$State);
! 601:
1.1 foxr 602:
603: my $State = $Socket->GetState(); # All action depends on the state.
604:
605: SocketDump(6, $Socket);
606:
607: if($Socket->Readable() != 0) {
1.4 foxr 608: # bad return from socket read. Currently this means that
609: # The socket has become disconnected. We fail the transaction.
610:
611: if(exists($ActiveTransactions{$Socket})) {
612: Debug(3,"Lond connection lost failing transaction");
613: FailTransaction($ActiveTransactions{$Socket});
614: }
615: $Watcher->cancel();
1.6 foxr 616: KillSocket($Socket);
1.4 foxr 617: return;
1.1 foxr 618: }
619: SocketDump(6,$Socket);
620:
621: $State = $Socket->GetState(); # Update in case of transition.
622: &Debug(6, "After read, state is ".$State);
623:
624: if($State eq "Initialized") {
625:
626:
627: } elsif ($State eq "ChallengeReceived") {
628: # The challenge must be echoed back; The state machine
629: # in the connection takes care of setting that up. Just
630: # need to transition to writable:
631:
1.8 ! foxr 632: $Watcher->cb(\&LondWritable);
1.1 foxr 633: $Watcher->poll("w");
634:
635: } elsif ($State eq "ChallengeReplied") {
636:
637:
638: } elsif ($State eq "RequestingKey") {
639: # The ok was received. Now we need to request the key
640: # That requires us to be writable:
641:
1.8 ! foxr 642: $Watcher->cb(\&LondWritable);
1.1 foxr 643: $Watcher->poll("w");
644:
645: } elsif ($State eq "ReceivingKey") {
646:
647: } elsif ($State eq "Idle") {
648: # If necessary, complete a transaction and then go into the
649: # idle queue.
1.8 ! foxr 650: $Watcher->cancel();
1.1 foxr 651: if(exists($ActiveTransactions{$Socket})) {
652: Debug(8,"Completing transaction!!");
653: CompleteTransaction($Socket,
654: $ActiveTransactions{$Socket});
655: }
656: ServerToIdle($Socket); # Next work unit or idle.
1.6 foxr 657:
1.1 foxr 658: } elsif ($State eq "SendingRequest") {
659: # We need to be writable for this and probably don't belong
660: # here inthe first place.
661:
662: Deubg(6, "SendingRequest state encountered in readable");
663: $Watcher->poll("w");
664: $Watcher->cb(\&LondWritable);
665:
666: } elsif ($State eq "ReceivingReply") {
667:
668:
669: } else {
670: # Invalid state.
671: Debug(4, "Invalid state in LondReadable");
672: }
673: }
1.3 albertel 674:
1.1 foxr 675: =pod
1.3 albertel 676:
1.1 foxr 677: =head2 LondWritable
1.3 albertel 678:
1.1 foxr 679: This function is called whenever a lond connection
680: becomes writable while there is a writeable monitoring
681: event. The action taken is very state dependent:
1.3 albertel 682:
1.1 foxr 683: =head3 State = Connected
1.3 albertel 684:
685: The connection is in the process of sending the 'init' hailing to the
686: lond on the remote end. The connection object''s Writable member is
687: called. On error, ConnectionError is called to destroy the connection
688: and remove it from the ActiveConnections hash
689:
1.1 foxr 690: =head3 Initialized
1.3 albertel 691:
692: 'init' has been sent, writability monitoring is removed and
693: readability monitoring is started with LondReadable as the callback.
694:
1.1 foxr 695: =head3 ChallengeReceived
1.3 albertel 696:
697: The connection has received the who are you challenge from the remote
698: system, and is in the process of sending the challenge
699: response. Writable is called.
700:
1.1 foxr 701: =head3 ChallengeReplied
1.3 albertel 702:
703: The connection has replied to the initial challenge The we switch to
704: monitoring readability looking for the server to reply with 'ok'.
705:
1.1 foxr 706: =head3 RequestingKey
1.3 albertel 707:
708: The connection is in the process of requesting its encryption key.
709: Writable is called.
710:
1.1 foxr 711: =head3 ReceivingKey
1.3 albertel 712:
713: The connection has sent the request for a key. Switch to readability
714: monitoring to accept the key
715:
1.1 foxr 716: =head3 SendingRequest
1.3 albertel 717:
718: The connection is in the process of sending a request to the server.
719: This request is part of a client transaction. All the states until
720: now represent the client setup protocol. Writable is called.
721:
1.1 foxr 722: =head3 ReceivingReply
723:
1.3 albertel 724: The connection has sent a request. Now it must receive a reply.
725: Readability monitoring is requested.
726:
727: This function is an event handler and therefore receives as
1.1 foxr 728: a parameter the event that has fired. The data for the watcher
729: of this event is a reference to a list of one or two elements,
730: depending on state. The first (and possibly only) element is the
731: socket. The second (present only if a request is in progress)
732: is the socket on which to return a reply to the caller.
733:
734: =cut
1.3 albertel 735:
1.1 foxr 736: sub LondWritable {
737: my $Event = shift;
738: my $Watcher = $Event->w;
1.8 ! foxr 739: my $Socket = $Watcher->data;
! 740: my $State = $Socket->GetState();
1.1 foxr 741:
1.8 ! foxr 742: Debug(6,"LondWritable State = ".$State."\n");
1.1 foxr 743:
1.8 ! foxr 744:
1.1 foxr 745: # Figure out what to do depending on the state of the socket:
746:
747:
748:
749:
750: SocketDump(6,$Socket);
751:
752: if ($State eq "Connected") {
753:
754: if ($Socket->Writable() != 0) {
755: # The write resulted in an error.
1.4 foxr 756: # We'll treat this as if the socket got disconnected:
1.5 foxr 757:
1.4 foxr 758: $Watcher->cancel();
1.6 foxr 759: KillSocket($Socket);
1.4 foxr 760: return;
1.1 foxr 761: }
1.4 foxr 762: # "init" is being sent...
763:
1.1 foxr 764:
765: } elsif ($State eq "Initialized") {
766:
767: # Now that init was sent, we switch
768: # to watching for readability:
769:
1.8 ! foxr 770: $Watcher->cb(\&LondReadable);
1.1 foxr 771: $Watcher->poll("r");
772:
773: } elsif ($State eq "ChallengeReceived") {
774: # We received the challenge, now we
775: # are echoing it back. This is a no-op,
776: # we're waiting for the state to change
777:
778: if($Socket->Writable() != 0) {
1.5 foxr 779:
780: $Watcher->cancel();
1.6 foxr 781: KillSocket($Socket);
1.5 foxr 782: return;
1.1 foxr 783: }
784:
785: } elsif ($State eq "ChallengeReplied") {
786: # The echo was sent back, so we switch
787: # to watching readability.
788:
1.8 ! foxr 789: $Watcher->cb(\&LondReadable);
1.1 foxr 790: $Watcher->poll("r");
791:
792: } elsif ($State eq "RequestingKey") {
793: # At this time we're requesting the key.
794: # again, this is essentially a no-op.
795: # we'll write the next chunk until the
796: # state changes.
797:
798: if($Socket->Writable() != 0) {
799: # Write resulted in an error.
1.5 foxr 800:
801: $Watcher->cancel();
1.6 foxr 802: KillSocket($Socket);
1.5 foxr 803: return;
804:
1.1 foxr 805: }
806: } elsif ($State eq "ReceivingKey") {
807: # Now we need to wait for the key
808: # to come back from the peer:
809:
1.8 ! foxr 810: $Watcher->cb(\&LondReadable);
1.1 foxr 811: $Watcher->poll("r");
812:
813: } elsif ($State eq "SendingRequest") {
814: # At this time we are sending a request to the
815: # peer... write the next chunk:
816:
817: if($Socket->Writable() != 0) {
818:
1.5 foxr 819: if(exists($ActiveTransactions{$Socket})) {
820: Debug(3, "Lond connection lost, failing transactions");
821: FailTransaction($ActiveTransactions{$Socket});
822: }
823: $Watcher->cancel();
1.6 foxr 824: KillSocket($Socket);
1.5 foxr 825: return;
826:
1.1 foxr 827: }
828:
829: } elsif ($State eq "ReceivingReply") {
830: # The send has completed. Wait for the
831: # data to come in for a reply.
832: Debug(8,"Writable sent request/receiving reply");
1.8 ! foxr 833: $Watcher->cb(\&LondReadable);
1.1 foxr 834: $Watcher->poll("r");
835:
836: } else {
837: # Control only passes here on an error:
838: # the socket state does not match any
839: # of the known states... so an error
840: # must be logged.
841:
842: &Debug(4, "Invalid socket state ".$State."\n");
843: }
844:
845: }
1.6 foxr 846: =pod
847:
848: =cut
849: sub QueueDelayed {
1.8 ! foxr 850: Debug(3,"QueueDelayed called");
! 851:
1.6 foxr 852: my $path = "$perlvar{'lonSockDir'}/delayed";
1.8 ! foxr 853:
! 854: Debug(4, "Delayed path: ".$path);
1.6 foxr 855: opendir(DIRHANDLE, $path);
1.8 ! foxr 856:
1.6 foxr 857: @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
1.8 ! foxr 858: Debug(4, "Got ".$alldelayed." delayed files");
1.6 foxr 859: closedir(DIRHANDLE);
860: my $dfname;
1.8 ! foxr 861: my $reqfile;
! 862: foreach $dfname (sort @alldelayed) {
! 863: $reqfile = "$path/$dfname";
! 864: Debug(4, "queueing ".$reqfile);
1.6 foxr 865: my $Handle = IO::File->new($reqfile);
866: my $cmd = <$Handle>;
1.8 ! foxr 867: chomp $cmd; # There may or may not be a newline...
! 868: $cmd = $cmd."\ny"; # now for sure there's exactly one newline.
1.7 foxr 869: my $Transaction = LondTransaction->new($cmd);
870: $Transaction->SetDeferred($reqfile);
871: QueueTransaction($Transaction);
1.6 foxr 872: }
873:
874: }
1.1 foxr 875:
876: =pod
1.3 albertel 877:
1.1 foxr 878: =head2 MakeLondConnection
1.3 albertel 879:
880: Create a new lond connection object, and start it towards its initial
881: idleness. Once idle, it becomes elligible to receive transactions
882: from the work queue. If the work queue is not empty when the
883: connection is completed and becomes idle, it will dequeue an entry and
884: start off on it.
885:
1.1 foxr 886: =cut
1.3 albertel 887:
1.1 foxr 888: sub MakeLondConnection {
889: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
890: .GetServerPort());
891:
892: my $Connection = LondConnection->new(&GetServerHost(),
893: &GetServerPort());
894:
895: if($Connection == undef) { # Needs to be more robust later.
1.5 foxr 896: Debug(0,"Failed to make a connection with lond.");
897: } else {
898: # The connection needs to have writability
899: # monitored in order to send the init sequence
900: # that starts the whole authentication/key
901: # exchange underway.
902: #
903: my $Socket = $Connection->GetSocket();
904: if($Socket == undef) {
905: die "did not get a socket from the connection";
906: } else {
907: &Debug(9,"MakeLondConnection got socket: ".$Socket);
908: }
1.1 foxr 909:
1.5 foxr 910:
911: $event = Event->io(fd => $Socket,
912: poll => 'w',
913: cb => \&LondWritable,
1.8 ! foxr 914: data => $Connection,
1.5 foxr 915: desc => 'Connection to lond server');
916: $ActiveConnections{$Connection} = $event;
917:
918: $ConnectionCount++;
1.8 ! foxr 919: Debug(4, "Connection count = ".$ConnectionCount);
1.6 foxr 920: if($ConnectionCount == 1) { # First Connection:
921: QueueDelayed;
922: }
1.1 foxr 923: }
924:
925: }
1.3 albertel 926:
1.1 foxr 927: =pod
1.3 albertel 928:
1.1 foxr 929: =head2 StartRequest
1.3 albertel 930:
931: Starts a lond request going on a specified lond connection.
932: parameters are:
933:
934: =item $Lond
935:
936: Connection to the lond that will send the transaction and receive the
937: reply.
938:
939: =item $Client
940:
941: Connection to the client that is making this request We got the
942: request from this socket, and when the request has been relayed to
943: lond and we get a reply back from lond it will get sent to this
944: socket.
945:
946: =item $Request
947:
948: The text of the request to send.
949:
1.1 foxr 950: =cut
951:
952: sub StartRequest {
953: my $Lond = shift;
1.7 foxr 954: my $Request = shift; # This is a LondTransaction.
1.1 foxr 955:
1.7 foxr 956: Debug(6, "StartRequest: ".$Request->getRequest());
1.1 foxr 957:
958: my $Socket = $Lond->GetSocket();
959:
1.7 foxr 960: $Request->Activate($Lond);
961: $ActiveTransactions{$Lond} = $Request;
1.1 foxr 962:
1.7 foxr 963: $Lond->InitiateTransaction($Request->getRequest());
1.8 ! foxr 964: $event = Event->io(fd => $Socket,
1.1 foxr 965: poll => "w",
966: cb => \&LondWritable,
967: data => $Lond,
968: desc => "lond transaction connection");
969: $ActiveConnections{$Lond} = $event;
970: Debug(8," Start Request made watcher data with ".$event->data."\n");
971: }
972:
973: =pod
1.3 albertel 974:
1.1 foxr 975: =head2 QueueTransaction
1.3 albertel 976:
977: If there is an idle lond connection, it is put to work doing this
978: transaction. Otherwise, the transaction is placed in the work queue.
979: If placed in the work queue and the maximum number of connections has
980: not yet been created, a new connection will be started. Our goal is
981: to eventually have a sufficient number of connections that the work
982: queue will typically be empty. parameters are:
983:
984: =item Socket
985:
986: open on the lonc client.
987:
988: =item Request
989:
990: data to send to the lond.
1.1 foxr 991:
992: =cut
1.3 albertel 993:
1.1 foxr 994: sub QueueTransaction {
995:
1.7 foxr 996: my $requestData = shift; # This is a LondTransaction.
997: my $cmd = $requestData->getRequest();
998:
999: Debug(6,"QueueTransaction: ".$cmd);
1.1 foxr 1000:
1001: my $LondSocket = $IdleConnections->pop();
1002: if(!defined $LondSocket) { # Need to queue request.
1003: Debug(8,"Must queue...");
1004: $WorkQueue->enqueue($requestData);
1005: if($ConnectionCount < $MaxConnectionCount) {
1006: Debug(4,"Starting additional lond connection");
1007: MakeLondConnection();
1008: }
1009: } else { # Can start the request:
1010: Debug(8,"Can start...");
1.7 foxr 1011: StartRequest($LondSocket, $requestData);
1.1 foxr 1012: }
1013: }
1014:
1015: #-------------------------- Lonc UNIX socket handling ---------------------
1.3 albertel 1016:
1.1 foxr 1017: =pod
1.3 albertel 1018:
1.1 foxr 1019: =head2 ClientRequest
1.3 albertel 1020:
1021: Callback that is called when data can be read from the UNIX domain
1022: socket connecting us with an apache server process.
1.1 foxr 1023:
1024: =cut
1025:
1026: sub ClientRequest {
1027: Debug(6, "ClientRequest");
1028: my $event = shift;
1029: my $watcher = $event->w;
1030: my $socket = $watcher->fd;
1031: my $data = $watcher->data;
1032: my $thisread;
1033:
1034: Debug(9, " Watcher named: ".$watcher->desc);
1035:
1036: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1037: Debug(8, "rcv: data length = ".length($thisread)
1038: ." read =".$thisread);
1039: unless (defined $rv && length($thisread)) {
1040: # Likely eof on socket.
1041: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1042: close($socket);
1043: $watcher->cancel();
1044: delete($ActiveClients{$socket});
1045: }
1046: Debug(8,"Data: ".$data." this read: ".$thisread);
1047: $data = $data.$thisread; # Append new data.
1048: $watcher->data($data);
1049: if($data =~ /(.*\n)/) { # Request entirely read.
1050: Debug(8, "Complete transaction received: ".$data);
1.8 ! foxr 1051: my $Transaction = LondTransaction->new($data);
1.7 foxr 1052: $Transaction->SetClient($socket);
1053: QueueTransaction($Transaction);
1.1 foxr 1054: $watcher->cancel(); # Done looking for input data.
1055: }
1056:
1057: }
1058:
1059:
1060: =pod
1.3 albertel 1061:
1.1 foxr 1062: =head2 NewClient
1.3 albertel 1063:
1064: Callback that is called when a connection is received on the unix
1065: socket for a new client of lonc. The callback is parameterized by the
1066: event.. which is a-priori assumed to be an io event, and therefore has
1067: an fd member that is the Listener socket. We Accept the connection
1068: and register a new event on the readability of that socket:
1069:
1.1 foxr 1070: =cut
1.3 albertel 1071:
1.1 foxr 1072: sub NewClient {
1073: Debug(6, "NewClient");
1074: my $event = shift; # Get the event parameters.
1075: my $watcher = $event->w;
1076: my $socket = $watcher->fd; # Get the event' socket.
1077: my $connection = $socket->accept(); # Accept the client connection.
1078: Debug(8,"Connection request accepted from "
1079: .GetPeername($connection, AF_UNIX));
1080:
1081:
1082: my $description = sprintf("Connection to lonc client %d",
1083: $ClientConnection);
1084: Debug(9, "Creating event named: ".$description);
1085: Event->io(cb => \&ClientRequest,
1086: poll => 'r',
1087: desc => $description,
1088: data => "",
1089: fd => $connection);
1090: $ActiveClients{$connection} = $ClientConnection;
1091: $ClientConnection++;
1092: }
1.3 albertel 1093:
1094: =pod
1095:
1096: =head2 GetLoncSocketPath
1097:
1098: Returns the name of the UNIX socket on which to listen for client
1099: connections.
1.1 foxr 1100:
1101: =cut
1.3 albertel 1102:
1.1 foxr 1103: sub GetLoncSocketPath {
1104: return $UnixSocketDir."/".GetServerHost();
1105: }
1106:
1.3 albertel 1107: =pod
1108:
1109: =head2 GetServerHost
1110:
1111: Returns the host whose lond we talk with.
1112:
1.1 foxr 1113: =cut
1.3 albertel 1114:
1.7 foxr 1115: sub GetServerHost {
1.1 foxr 1116: return $RemoteHost; # Setup by the fork.
1117: }
1.3 albertel 1118:
1119: =pod
1120:
1121: =head2 GetServerPort
1122:
1123: Returns the lond port number.
1124:
1.1 foxr 1125: =cut
1.3 albertel 1126:
1.7 foxr 1127: sub GetServerPort {
1.1 foxr 1128: return $perlvar{londPort};
1129: }
1.3 albertel 1130:
1131: =pod
1132:
1133: =head2 SetupLoncListener
1134:
1135: Setup a lonc listener event. The event is called when the socket
1136: becomes readable.. that corresponds to the receipt of a new
1137: connection. The event handler established will accept the connection
1138: (creating a communcations channel), that int turn will establish
1139: another event handler to subess requests.
1.1 foxr 1140:
1141: =cut
1.3 albertel 1142:
1.1 foxr 1143: sub SetupLoncListener {
1144:
1145: my $socket;
1146: my $SocketName = GetLoncSocketPath();
1147: unlink($SocketName);
1.7 foxr 1148: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1.1 foxr 1149: Listen => 10,
1150: Type => SOCK_STREAM)) {
1151: die "Failed to create a lonc listner socket";
1152: }
1153: Event->io(cb => \&NewClient,
1154: poll => 'r',
1155: desc => 'Lonc listener Unix Socket',
1156: fd => $socket);
1157: }
1158:
1159: =pod
1.3 albertel 1160:
1.1 foxr 1161: =head2 ChildProcess
1162:
1163: This sub implements a child process for a single lonc daemon.
1164:
1165: =cut
1166:
1167: sub ChildProcess {
1168:
1169: print "Loncnew\n";
1170:
1171: # For now turn off signals.
1172:
1173: $SIG{QUIT} = IGNORE;
1174: $SIG{HUP} = IGNORE;
1175: $SIG{USR1} = IGNORE;
1176: $SIG{INT} = IGNORE;
1177: $SIG{CHLD} = IGNORE;
1178: $SIG{__DIE__} = IGNORE;
1179:
1180: SetupTimer();
1181:
1182: SetupLoncListener();
1183:
1184: $Event::Debuglevel = $DebugLevel;
1185:
1186: Debug(9, "Making initial lond connection for ".$RemoteHost);
1187:
1188: # Setup the initial server connection:
1189:
1190: &MakeLondConnection();
1.5 foxr 1191:
1192: if($ConnectionCount == 0) {
1193: Debug(1,"Could not make initial connection..\n");
1194: Debug(1,"Will retry when there's work to do\n");
1195: }
1.1 foxr 1196: Debug(9,"Entering event loop");
1197: my $ret = Event::loop(); # Start the main event loop.
1198:
1199:
1200: die "Main event loop exited!!!";
1201: }
1202:
1203: # Create a new child for host passed in:
1204:
1205: sub CreateChild {
1206: my $host = shift;
1207: $RemoteHost = $host;
1208: Debug(3, "Forking off child for ".$RemoteHost);
1209: sleep(5);
1210: $pid = fork;
1211: if($pid) { # Parent
1212: $ChildHash{$pid} = $RemoteHost;
1213: } else { # child.
1.5 foxr 1214: ShowStatus("Connected to ".$RemoteHost);
1.1 foxr 1215: ChildProcess;
1216: }
1217:
1218: }
1219: #
1220: # Parent process logic pass 1:
1221: # For each entry in the hosts table, we will
1222: # fork off an instance of ChildProcess to service the transactions
1223: # to that host. Each pid will be entered in a global hash
1224: # with the value of the key, the host.
1225: # The parent will then enter a loop to wait for process exits.
1226: # Each exit gets logged and the child gets restarted.
1227: #
1228:
1.5 foxr 1229: #
1230: # Fork and start in new session so hang-up isn't going to
1231: # happen without intent.
1232: #
1233:
1234:
1.6 foxr 1235:
1236:
1.8 ! foxr 1237:
1.6 foxr 1238:
1239: ShowStatus("Forming new session");
1240: my $childpid = fork;
1241: if ($childpid != 0) {
1242: sleep 4; # Give child a chacne to break to
1243: exit 0; # a new sesion.
1244: }
1.8 ! foxr 1245: #
! 1246: # Write my pid into the pid file so I can be located
! 1247: #
! 1248:
! 1249: ShowStatus("Parent writing pid file:");
! 1250: $execdir = $perlvar{'lonDaemons'};
! 1251: open (PIDSAVE, ">$execdir/logs/lonc.pid");
! 1252: print PIDSAVE "$$\n";
! 1253: close(PIDSAVE);
1.6 foxr 1254:
1255: if (POSIX::setsid() < 0) {
1256: print "Could not create new session\n";
1257: exit -1;
1258: }
1.5 foxr 1259:
1260: ShowStatus("Forking node servers");
1261:
1.1 foxr 1262: my $HostIterator = LondConnection::GetHostIterator;
1263: while (! $HostIterator->end()) {
1264:
1265: $hostentryref = $HostIterator->get();
1266: CreateChild($hostentryref->[0]);
1267: $HostIterator->next();
1268: }
1269:
1270: # Maintain the population:
1.5 foxr 1271:
1272: ShowStatus("Parent keeping the flock");
1.1 foxr 1273:
1274: while(1) {
1275: $deadchild = wait();
1276: if(exists $ChildHash{$deadchild}) { # need to restart.
1277: $deadhost = $ChildHash{$deadchild};
1278: delete($ChildHash{$deadchild});
1279: Debug(4,"Lost child pid= ".$deadchild.
1280: "Connected to host ".$deadhost);
1281: CreateChild($deadhost);
1282: }
1283: }
1284:
1285: =head1 Theory
1.3 albertel 1286:
1287: The event class is used to build this as a single process with an
1288: event driven model. The following events are handled:
1.1 foxr 1289:
1290: =item UNIX Socket connection Received
1291:
1292: =item Request data arrives on UNIX data transfer socket.
1293:
1294: =item lond connection becomes writable.
1295:
1296: =item timer fires at 1 second intervals.
1297:
1298: All sockets are run in non-blocking mode. Timeouts managed by the timer
1299: handler prevents hung connections.
1300:
1301: Key data structures:
1302:
1.3 albertel 1303: =item RequestQueue
1304:
1305: A queue of requests received from UNIX sockets that are
1306: waiting for a chance to be forwarded on a lond connection socket.
1307:
1308: =item ActiveConnections
1309:
1310: A hash of lond connections that have transactions in process that are
1311: available to be timed out.
1312:
1313: =item ActiveTransactions
1314:
1315: A hash indexed by lond connections that contain the client reply
1316: socket for each connection that has an active transaction on it.
1317:
1318: =item IdleConnections
1319:
1320: A hash of lond connections that have no work to do. These connections
1321: can be closed if they are idle for a long enough time.
1.1 foxr 1322:
1323: =cut
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