1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # lonc maintains the connections to remote computers
4: #
5: # $Id: loncnew,v 1.13 2003/07/02 01:31:55 foxr Exp $
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: #
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).
37: # - Add general logic for dispatching requests and timeouts. (done).
38: # - Add support for the lonc/lond requests. (done).
39: # - Add logging/status monitoring.
40: # - Add Signal handling - HUP restarts. USR1 status report.
41: # - Add Configuration file I/O (done).
42: # - Add management/status request interface.
43: # - Add deferred request capability. (done)
44: # - Detect transmission timeouts.
45: #
46:
47: # Change log:
48: # $Log: loncnew,v $
49: # Revision 1.13 2003/07/02 01:31:55 foxr
50: # Added kill -HUP logic (restart).
51: #
52: # Revision 1.11 2003/06/25 01:54:44 foxr
53: # Fix more problems with transaction failure.
54: #
55: # Revision 1.10 2003/06/24 02:46:04 foxr
56: # Put a limit on the number of times we'll retry a connection.
57: # Start getting the signal stuff put in as well...note that need to get signals
58: # going or else 6the client will permanently give up on dead servers.
59: #
60: # Revision 1.9 2003/06/13 02:38:43 foxr
61: # Add logging in 'expected format'
62: #
63: # Revision 1.8 2003/06/11 02:04:35 foxr
64: # Support delayed transactions... this is done uniformly by encapsulating
65: # transactions in an object ... a LondTransaction that is implemented by
66: # LondTransaction.pm
67: #
68: # Revision 1.7 2003/06/03 01:59:39 foxr
69: # complete coding to support deferred transactions.
70: #
71: #
72:
73: use lib "/home/httpd/lib/perl/";
74: use lib "/home/foxr/newloncapa/types";
75: use Event qw(:DEFAULT );
76: use POSIX qw(:signal_h);
77: use POSIX;
78: use IO::Socket;
79: use IO::Socket::INET;
80: use IO::Socket::UNIX;
81: use IO::File;
82: use IO::Handle;
83: use Socket;
84: use Crypt::IDEA;
85: use LONCAPA::Queue;
86: use LONCAPA::Stack;
87: use LONCAPA::LondConnection;
88: use LONCAPA::LondTransaction;
89: use LONCAPA::Configuration;
90: use LONCAPA::HashIterator;
91:
92:
93: #
94: # Disable all signals we might receive from outside for now.
95: #
96: $SIG{QUIT} = IGNORE;
97: $SIG{HUP} = IGNORE;
98: $SIG{USR1} = IGNORE;
99: $SIG{INT} = IGNORE;
100: $SIG{CHLD} = IGNORE;
101: $SIG{__DIE__} = IGNORE;
102:
103:
104: # Read the httpd configuration file to get perl variables
105: # normally set in apache modules:
106:
107: my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
108: my %perlvar = %{$perlvarref};
109:
110: #
111: # parent and shared variables.
112:
113: my %ChildHash; # by pid -> host.
114:
115:
116: my $MaxConnectionCount = 10; # Will get from config later.
117: my $ClientConnection = 0; # Uniquifier for client events.
118:
119: my $DebugLevel = 0;
120: my $IdleTimeout= 3600; # Wait an hour before pruning connections.
121:
122: #
123: # The variables below are only used by the child processes.
124: #
125: my $RemoteHost; # Name of host child is talking to.
126: my $UnixSocketDir= "/home/httpd/sockets";
127: my $IdleConnections = Stack->new(); # Set of idle connections
128: my %ActiveConnections; # Connections to the remote lond.
129: my %ActiveTransactions; # LondTransactions in flight.
130: my %ActiveClients; # Serial numbers of active clients by socket.
131: my $WorkQueue = Queue->new(); # Queue of pending transactions.
132: my $ConnectionCount = 0;
133: my $IdleSeconds = 0; # Number of seconds idle.
134: my $Status = ""; # Current status string.
135: my $ConnectionRetries=5; # Number of connection retries allowed.
136: my $ConnectionRetriesLeft=5; # Number of connection retries remaining.
137:
138: #
139: # The hash below gives the HTML format for log messages
140: # given a severity.
141: #
142: my %LogFormats;
143:
144: $LogFormats{"CRITICAL"} = "<font color=red>CRITICAL: %s</font>";
145: $LogFormats{"SUCCESS"} = "<font color=green>SUCCESS: %s</font>";
146: $LogFormats{"INFO"} = "<font color=yellow>INFO: %s</font>";
147: $LogFormats{"WARNING"} = "<font color=blue>WARNING: %s</font>";
148: $LogFormats{"DEFAULT"} = " %s ";
149:
150:
151:
152: =pod
153:
154: =head2 LogPerm
155:
156: Makes an entry into the permanent log file.
157:
158: =cut
159: sub LogPerm {
160: my $message=shift;
161: my $execdir=$perlvar{'lonDaemons'};
162: my $now=time;
163: my $local=localtime($now);
164: my $fh=IO::File->new(">>$execdir/logs/lonnet.perm.log");
165: print $fh "$now:$message:$local\n";
166: }
167:
168: =pod
169:
170: =head2 Log
171:
172: Logs a message to the log file.
173: Parameters:
174:
175: =item severity
176:
177: One of CRITICAL, WARNING, INFO, SUCCESS used to select the
178: format string used to format the message. if the severity is
179: not a defined severity the Default format string is used.
180:
181: =item message
182:
183: The base message. In addtion to the format string, the message
184: will be appended to a string containing the name of our remote
185: host and the time will be formatted into the message.
186:
187: =cut
188:
189: sub Log {
190: my $severity = shift;
191: my $message = shift;
192:
193: if(!$LogFormats{$severity}) {
194: $severity = "DEFAULT";
195: }
196:
197: my $format = $LogFormats{$severity};
198:
199: # Put the window dressing in in front of the message format:
200:
201: my $now = time;
202: my $local = localtime($now);
203: my $finalformat = "$local ($$) [$RemoteHost] [$Status] ";
204: my $finalformat = $finalformat.$format."\n";
205:
206: # open the file and put the result.
207:
208: my $execdir = $perlvar{'lonDaemons'};
209: my $fh = IO::File->new(">>$execdir/logs/lonc.log");
210: my $msg = sprintf($finalformat, $message);
211: print $fh $msg;
212:
213:
214: }
215:
216:
217: =pod
218:
219: =head2 GetPeerName
220:
221: Returns the name of the host that a socket object is connected to.
222:
223: =cut
224:
225: sub GetPeername {
226: my $connection = shift;
227: my $AdrFamily = shift;
228: my $peer = $connection->peername();
229: my $peerport;
230: my $peerip;
231: if($AdrFamily == AF_INET) {
232: ($peerport, $peerip) = sockaddr_in($peer);
233: my $peername = gethostbyaddr($iaddr, $AdrFamily);
234: return $peername;
235: } elsif ($AdrFamily == AF_UNIX) {
236: my $peerfile;
237: ($peerfile) = sockaddr_un($peer);
238: return $peerfile;
239: }
240: }
241: #----------------------------- Timer management ------------------------
242: =pod
243:
244: =head2 Debug
245:
246: Invoked to issue a debug message.
247:
248: =cut
249:
250: sub Debug {
251: my $level = shift;
252: my $message = shift;
253: if ($level <= $DebugLevel) {
254: print $message." host = ".$RemoteHost."\n";
255: }
256: }
257:
258: sub SocketDump {
259: my $level = shift;
260: my $socket= shift;
261: if($level <= $DebugLevel) {
262: $socket->Dump();
263: }
264: }
265:
266: =pod
267:
268: =head2 ShowStatus
269:
270: Place some text as our pid status.
271: and as what we return in a SIGUSR1
272:
273: =cut
274: sub ShowStatus {
275: my $state = shift;
276: my $now = time;
277: my $local = localtime($now);
278: $Status = $local.": ".$state;
279: $0='lonc: '.$state.' '.$local;
280: }
281:
282: =pod
283:
284: =head2 Tick
285:
286: Invoked each timer tick.
287:
288: =cut
289:
290:
291: sub Tick {
292: my $client;
293: ShowStatus(GetServerHost()." Connection count: ".$ConnectionCount);
294:
295: # Is it time to prune connection count:
296:
297:
298: if($IdleConnections->Count() &&
299: ($WorkQueue->Count() == 0)) { # Idle connections and nothing to do?
300: $IdleSeconds++;
301: if($IdleSeconds > $IdleTimeout) { # Prune a connection...
302: $Socket = $IdleConnections->pop();
303: KillSocket($Socket);
304: }
305: } else {
306: $IdleSeconds = 0; # Reset idle count if not idle.
307: }
308:
309: # Do we have work in the queue, but no connections to service them?
310: # If so, try to make some new connections to get things going again.
311: #
312:
313: my $Requests = $WorkQueue->Count();
314: if (($ConnectionCount == 0) && ($Requests > 0)) {
315: if ($ConnectionRetriesLeft > 0) {
316: my $Connections = ($Requests <= $MaxConnectionCount) ?
317: $Requests : $MaxConnectionCount;
318: Debug(1,"Work but no connections, start ".$Connections." of them");
319: for ($i =0; $i < $Connections; $i++) {
320: MakeLondConnection();
321: }
322: } else {
323: Debug(1,"Work in queue, but gave up on connections..flushing\n");
324: EmptyQueue(); # Connections can't be established.
325: }
326:
327: }
328: }
329:
330: =pod
331:
332: =head2 SetupTimer
333:
334: Sets up a 1 per sec recurring timer event. The event handler is used to:
335:
336: =item
337:
338: Trigger timeouts on communications along active sockets.
339:
340: =item
341:
342: Trigger disconnections of idle sockets.
343:
344: =cut
345:
346: sub SetupTimer {
347: Debug(6, "SetupTimer");
348: Event->timer(interval => 1, debug => 1, cb => \&Tick );
349: }
350:
351: =pod
352:
353: =head2 ServerToIdle
354:
355: This function is called when a connection to the server is
356: ready for more work.
357:
358: If there is work in the Work queue the top element is dequeued
359: and the connection will start to work on it. If the work queue is
360: empty, the connection is pushed on the idle connection stack where
361: it will either get another work unit, or alternatively, if it sits there
362: long enough, it will be shut down and released.
363:
364: =cut
365:
366: sub ServerToIdle {
367: my $Socket = shift; # Get the socket.
368: delete($ActiveTransactions{$Socket}); # Server has no transaction
369:
370: &Debug(6, "Server to idle");
371:
372: # If there's work to do, start the transaction:
373:
374: $reqdata = $WorkQueue->dequeue(); # This is a LondTransaction
375: unless($reqdata eq undef) {
376: Debug(9, "Queue gave request data: ".$reqdata->getRequest());
377: &StartRequest($Socket, $reqdata);
378:
379: } else {
380:
381: # There's no work waiting, so push the server to idle list.
382: &Debug(8, "No new work requests, server connection going idle");
383: $IdleConnections->push($Socket);
384: }
385: }
386:
387: =pod
388:
389: =head2 ClientWritable
390:
391: Event callback for when a client socket is writable.
392:
393: This callback is established when a transaction reponse is
394: avaiable from lond. The response is forwarded to the unix socket
395: as it becomes writable in this sub.
396:
397: Parameters:
398:
399: =item Event
400:
401: The event that has been triggered. Event->w->data is
402: the data and Event->w->fd is the socket to write.
403:
404: =cut
405:
406: sub ClientWritable {
407: my $Event = shift;
408: my $Watcher = $Event->w;
409: my $Data = $Watcher->data;
410: my $Socket = $Watcher->fd;
411:
412: # Try to send the data:
413:
414: &Debug(6, "ClientWritable writing".$Data);
415: &Debug(9, "Socket is: ".$Socket);
416:
417: if($Socket->connected) {
418: my $result = $Socket->send($Data, 0);
419:
420: # $result undefined: the write failed.
421: # otherwise $result is the number of bytes written.
422: # Remove that preceding string from the data.
423: # If the resulting data is empty, destroy the watcher
424: # and set up a read event handler to accept the next
425: # request.
426:
427: &Debug(9,"Send result is ".$result." Defined: ".defined($result));
428: if(defined($result)) {
429: &Debug(9, "send result was defined");
430: if($result == length($Data)) { # Entire string sent.
431: &Debug(9, "ClientWritable data all written");
432: $Watcher->cancel();
433: #
434: # Set up to read next request from socket:
435:
436: my $descr = sprintf("Connection to lonc client %d",
437: $ActiveClients{$Socket});
438: Event->io(cb => \&ClientRequest,
439: poll => 'r',
440: desc => $descr,
441: data => "",
442: fd => $Socket);
443:
444: } else { # Partial string sent.
445: $Watcher->data(substr($Data, $result));
446: }
447:
448: } else { # Error of some sort...
449:
450: # Some errnos are possible:
451: my $errno = $!;
452: if($errno == POSIX::EWOULDBLOCK ||
453: $errno == POSIX::EAGAIN ||
454: $errno == POSIX::EINTR) {
455: # No action taken?
456: } else { # Unanticipated errno.
457: &Debug(5,"ClientWritable error or peer shutdown".$RemoteHost);
458: $Watcher->cancel; # Stop the watcher.
459: $Socket->shutdown(2); # Kill connection
460: $Socket->close(); # Close the socket.
461: }
462:
463: }
464: } else {
465: $Watcher->cancel(); # A delayed request...just cancel.
466: }
467: }
468:
469: =pod
470:
471: =head2 CompleteTransaction
472:
473: Called when the reply data has been received for a lond
474: transaction. The reply data must now be sent to the
475: ultimate client on the other end of the Unix socket. This is
476: done by setting up a writable event for the socket with the
477: data the reply data.
478:
479: Parameters:
480:
481: =item Socket
482:
483: Socket on which the lond transaction occured. This is a
484: LondConnection. The data received is in the TransactionReply member.
485:
486: =item Transaction
487:
488: The transaction that is being completed.
489:
490: =cut
491:
492: sub CompleteTransaction {
493: &Debug(6,"Complete transaction");
494: my $Socket = shift;
495: my $Transaction = shift;
496:
497: if (!$Transaction->isDeferred()) { # Normal transaction
498: my $data = $Socket->GetReply(); # Data to send.
499: StartClientReply($Transaction, $data);
500: } else { # Delete deferred transaction file.
501: Log("SUCCESS", "A delayed transaction was completed");
502: LogPerm("S:$Client:".$Transaction->getRequest());
503: unlink $Transaction->getFile();
504: }
505: }
506: =pod
507: =head1 StartClientReply
508:
509: Initiates a reply to a client where the reply data is a parameter.
510:
511: =head2 parameters:
512:
513: =item Transaction
514:
515: The transaction for which we are responding to the client.
516:
517: =item data
518:
519: The data to send to apached client.
520:
521: =cut
522: sub StartClientReply {
523: my $Transaction = shift;
524: my $data = shift;
525:
526:
527: my $Client = $Transaction->getClient();
528:
529: &Debug(8," Reply was: ".$data);
530: my $Serial = $ActiveClients{$Client};
531: my $desc = sprintf("Connection to lonc client %d",
532:
533: $Serial);
534: Event->io(fd => $Client,
535: poll => "w",
536: desc => $desc,
537: cb => \&ClientWritable,
538: data => $data);
539: }
540: =pod
541: =head2 FailTransaction
542:
543: Finishes a transaction with failure because the associated lond socket
544: disconnected. There are two possibilities:
545: - The transaction is deferred: in which case we just quietly
546: delete the transaction since there is no client connection.
547: - The transaction is 'live' in which case we initiate the sending
548: of "con_lost" to the client.
549:
550: Deleting the transaction means killing it from the
551: %ActiveTransactions hash.
552:
553: Parameters:
554:
555: =item client
556:
557: The LondTransaction we are failing.
558:
559: =cut
560:
561: sub FailTransaction {
562: my $transaction = shift;
563: Debug(1, "Failing transaction: ".$transaction->getRequest());
564: if (!$transaction->isDeferred()) { # If the transaction is deferred we'll get to it.
565: my $client = $transaction->getClient();
566: Debug(1," Replying con_lost to ".$transaction->getRequest());
567: StartClientReply($transaction, "con_lost\n");
568: }
569:
570: }
571:
572: =pod
573: =head1 EmptyQueue
574:
575: Fails all items in the work queue with con_lost.
576: Note that each item in the work queue is a transaction.
577:
578: =cut
579: sub EmptyQueue {
580: while($WorkQueue->Count()) {
581: my $request = $WorkQueue->dequeue(); # This is a transaction
582: FailTransaction($request);
583: }
584: }
585:
586: =pod
587:
588: =head2 CloseAllLondConnections
589:
590: Close all connections open on lond prior to exit e.g.
591:
592: =cut
593: sub CloseAllLondConnections {
594: foreach $Socket (keys %ActiveConnections) {
595: KillSocket($Socket);
596: }
597: }
598: =cut
599:
600: =pod
601:
602: =head2 KillSocket
603:
604: Destroys a socket. This function can be called either when a socket
605: has died of 'natural' causes or because a socket needs to be pruned due to
606: idleness. If the socket has died naturally, if there are no longer any
607: live connections a new connection is created (in case there are transactions
608: in the queue). If the socket has been pruned, it is never re-created.
609:
610: Parameters:
611:
612: =item Socket
613:
614: The socket to kill off.
615:
616: =item Restart
617:
618: nonzero if we are allowed to create a new connection.
619:
620:
621: =cut
622: sub KillSocket {
623: my $Socket = shift;
624:
625: $Socket->Shutdown();
626:
627: # If the socket came from the active connection set,
628: # delete its transaction... note that FailTransaction should
629: # already have been called!!!
630: # otherwise it came from the idle set.
631: #
632:
633: if(exists($ActiveTransactions{$Socket})) {
634: delete ($ActiveTransactions{$Socket});
635: }
636: if(exists($ActiveConnections{$Socket})) {
637: delete($ActiveConnections{$Socket});
638: }
639: $ConnectionCount--;
640:
641: # If the connection count has gone to zero and there is work in the
642: # work queue, the work all gets failed with con_lost.
643: #
644: if($ConnectionCount == 0) {
645: EmptyQueue;
646: }
647: }
648:
649: =pod
650:
651: =head2 LondReadable
652:
653: This function is called whenever a lond connection
654: is readable. The action is state dependent:
655:
656: =head3 State=Initialized
657:
658: We''re waiting for the challenge, this is a no-op until the
659: state changes.
660:
661: =head3 State=Challenged
662:
663: The challenge has arrived we need to transition to Writable.
664: The connection must echo the challenge back.
665:
666: =head3 State=ChallengeReplied
667:
668: The challenge has been replied to. The we are receiveing the
669: 'ok' from the partner.
670:
671: =head3 State=RequestingKey
672:
673: The ok has been received and we need to send the request for
674: an encryption key. Transition to writable for that.
675:
676: =head3 State=ReceivingKey
677:
678: The the key has been requested, now we are reading the new key.
679:
680: =head3 State=Idle
681:
682: The encryption key has been negotiated or we have finished
683: reading data from the a transaction. If the callback data has
684: a client as well as the socket iformation, then we are
685: doing a transaction and the data received is relayed to the client
686: before the socket is put on the idle list.
687:
688: =head3 State=SendingRequest
689:
690: I do not think this state can be received here, but if it is,
691: the appropriate thing to do is to transition to writable, and send
692: the request.
693:
694: =head3 State=ReceivingReply
695:
696: We finished sending the request to the server and now transition
697: to readable to receive the reply.
698:
699: The parameter to this function are:
700:
701: The event. Implicit in this is the watcher and its data. The data
702: contains at least the lond connection object and, if a
703: transaction is in progress, the socket attached to the local client.
704:
705: =cut
706:
707: sub LondReadable {
708:
709: my $Event = shift;
710: my $Watcher = $Event->w;
711: my $Socket = $Watcher->data;
712: my $client = undef;
713:
714: &Debug(6,"LondReadable called state = ".$State);
715:
716:
717: my $State = $Socket->GetState(); # All action depends on the state.
718:
719: SocketDump(6, $Socket);
720: my $status = $Socket->Readable();
721: &Debug(2, "Socket->Readable returned: $status");
722:
723: if($status != 0) {
724: # bad return from socket read. Currently this means that
725: # The socket has become disconnected. We fail the transaction.
726:
727: if(exists($ActiveTransactions{$Socket})) {
728: Debug(3,"Lond connection lost failing transaction");
729: FailTransaction($ActiveTransactions{$Socket});
730: }
731: $Watcher->cancel();
732: KillSocket($Socket);
733: return;
734: }
735: SocketDump(6,$Socket);
736:
737: $State = $Socket->GetState(); # Update in case of transition.
738: &Debug(6, "After read, state is ".$State);
739:
740: if($State eq "Initialized") {
741:
742:
743: } elsif ($State eq "ChallengeReceived") {
744: # The challenge must be echoed back; The state machine
745: # in the connection takes care of setting that up. Just
746: # need to transition to writable:
747:
748: $Watcher->cb(\&LondWritable);
749: $Watcher->poll("w");
750:
751: } elsif ($State eq "ChallengeReplied") {
752:
753:
754: } elsif ($State eq "RequestingKey") {
755: # The ok was received. Now we need to request the key
756: # That requires us to be writable:
757:
758: $Watcher->cb(\&LondWritable);
759: $Watcher->poll("w");
760:
761: } elsif ($State eq "ReceivingKey") {
762:
763: } elsif ($State eq "Idle") {
764: # If necessary, complete a transaction and then go into the
765: # idle queue.
766: $Watcher->cancel();
767: if(exists($ActiveTransactions{$Socket})) {
768: Debug(8,"Completing transaction!!");
769: CompleteTransaction($Socket,
770: $ActiveTransactions{$Socket});
771: } else {
772: Log("SUCCESS", "Connection ".$ConnectionCount." to "
773: .$RemoteHost." now ready for action");
774: }
775: ServerToIdle($Socket); # Next work unit or idle.
776:
777: } elsif ($State eq "SendingRequest") {
778: # We need to be writable for this and probably don't belong
779: # here inthe first place.
780:
781: Deubg(6, "SendingRequest state encountered in readable");
782: $Watcher->poll("w");
783: $Watcher->cb(\&LondWritable);
784:
785: } elsif ($State eq "ReceivingReply") {
786:
787:
788: } else {
789: # Invalid state.
790: Debug(4, "Invalid state in LondReadable");
791: }
792: }
793:
794: =pod
795:
796: =head2 LondWritable
797:
798: This function is called whenever a lond connection
799: becomes writable while there is a writeable monitoring
800: event. The action taken is very state dependent:
801:
802: =head3 State = Connected
803:
804: The connection is in the process of sending the 'init' hailing to the
805: lond on the remote end. The connection object''s Writable member is
806: called. On error, ConnectionError is called to destroy the connection
807: and remove it from the ActiveConnections hash
808:
809: =head3 Initialized
810:
811: 'init' has been sent, writability monitoring is removed and
812: readability monitoring is started with LondReadable as the callback.
813:
814: =head3 ChallengeReceived
815:
816: The connection has received the who are you challenge from the remote
817: system, and is in the process of sending the challenge
818: response. Writable is called.
819:
820: =head3 ChallengeReplied
821:
822: The connection has replied to the initial challenge The we switch to
823: monitoring readability looking for the server to reply with 'ok'.
824:
825: =head3 RequestingKey
826:
827: The connection is in the process of requesting its encryption key.
828: Writable is called.
829:
830: =head3 ReceivingKey
831:
832: The connection has sent the request for a key. Switch to readability
833: monitoring to accept the key
834:
835: =head3 SendingRequest
836:
837: The connection is in the process of sending a request to the server.
838: This request is part of a client transaction. All the states until
839: now represent the client setup protocol. Writable is called.
840:
841: =head3 ReceivingReply
842:
843: The connection has sent a request. Now it must receive a reply.
844: Readability monitoring is requested.
845:
846: This function is an event handler and therefore receives as
847: a parameter the event that has fired. The data for the watcher
848: of this event is a reference to a list of one or two elements,
849: depending on state. The first (and possibly only) element is the
850: socket. The second (present only if a request is in progress)
851: is the socket on which to return a reply to the caller.
852:
853: =cut
854:
855: sub LondWritable {
856: my $Event = shift;
857: my $Watcher = $Event->w;
858: my $Socket = $Watcher->data;
859: my $State = $Socket->GetState();
860:
861: Debug(6,"LondWritable State = ".$State."\n");
862:
863:
864: # Figure out what to do depending on the state of the socket:
865:
866:
867:
868:
869: SocketDump(6,$Socket);
870:
871: if ($State eq "Connected") {
872:
873: if ($Socket->Writable() != 0) {
874: # The write resulted in an error.
875: # We'll treat this as if the socket got disconnected:
876: Log("WARNING", "Connection to ".$RemoteHost.
877: " has been disconnected");
878: $Watcher->cancel();
879: KillSocket($Socket);
880: return;
881: }
882: # "init" is being sent...
883:
884:
885: } elsif ($State eq "Initialized") {
886:
887: # Now that init was sent, we switch
888: # to watching for readability:
889:
890: $Watcher->cb(\&LondReadable);
891: $Watcher->poll("r");
892:
893: } elsif ($State eq "ChallengeReceived") {
894: # We received the challenge, now we
895: # are echoing it back. This is a no-op,
896: # we're waiting for the state to change
897:
898: if($Socket->Writable() != 0) {
899:
900: $Watcher->cancel();
901: KillSocket($Socket);
902: return;
903: }
904:
905: } elsif ($State eq "ChallengeReplied") {
906: # The echo was sent back, so we switch
907: # to watching readability.
908:
909: $Watcher->cb(\&LondReadable);
910: $Watcher->poll("r");
911:
912: } elsif ($State eq "RequestingKey") {
913: # At this time we're requesting the key.
914: # again, this is essentially a no-op.
915: # we'll write the next chunk until the
916: # state changes.
917:
918: if($Socket->Writable() != 0) {
919: # Write resulted in an error.
920:
921: $Watcher->cancel();
922: KillSocket($Socket);
923: return;
924:
925: }
926: } elsif ($State eq "ReceivingKey") {
927: # Now we need to wait for the key
928: # to come back from the peer:
929:
930: $Watcher->cb(\&LondReadable);
931: $Watcher->poll("r");
932:
933: } elsif ($State eq "SendingRequest") {
934: # At this time we are sending a request to the
935: # peer... write the next chunk:
936:
937: if($Socket->Writable() != 0) {
938:
939: if(exists($ActiveTransactions{$Socket})) {
940: Debug(3, "Lond connection lost, failing transactions");
941: FailTransaction($ActiveTransactions{$Socket});
942: }
943: $Watcher->cancel();
944: KillSocket($Socket);
945: return;
946:
947: }
948:
949: } elsif ($State eq "ReceivingReply") {
950: # The send has completed. Wait for the
951: # data to come in for a reply.
952: Debug(8,"Writable sent request/receiving reply");
953: $Watcher->cb(\&LondReadable);
954: $Watcher->poll("r");
955:
956: } else {
957: # Control only passes here on an error:
958: # the socket state does not match any
959: # of the known states... so an error
960: # must be logged.
961:
962: &Debug(4, "Invalid socket state ".$State."\n");
963: }
964:
965: }
966: =pod
967:
968: =cut
969: sub QueueDelayed {
970: Debug(3,"QueueDelayed called");
971:
972: my $path = "$perlvar{'lonSockDir'}/delayed";
973:
974: Debug(4, "Delayed path: ".$path);
975: opendir(DIRHANDLE, $path);
976:
977: @alldelayed = grep /\.$RemoteHost$/, readdir DIRHANDLE;
978: Debug(4, "Got ".$alldelayed." delayed files");
979: closedir(DIRHANDLE);
980: my $dfname;
981: my $reqfile;
982: foreach $dfname (sort @alldelayed) {
983: $reqfile = "$path/$dfname";
984: Debug(4, "queueing ".$reqfile);
985: my $Handle = IO::File->new($reqfile);
986: my $cmd = <$Handle>;
987: chomp $cmd; # There may or may not be a newline...
988: $cmd = $cmd."\n"; # now for sure there's exactly one newline.
989: my $Transaction = LondTransaction->new($cmd);
990: $Transaction->SetDeferred($reqfile);
991: QueueTransaction($Transaction);
992: }
993:
994: }
995:
996: =pod
997:
998: =head2 MakeLondConnection
999:
1000: Create a new lond connection object, and start it towards its initial
1001: idleness. Once idle, it becomes elligible to receive transactions
1002: from the work queue. If the work queue is not empty when the
1003: connection is completed and becomes idle, it will dequeue an entry and
1004: start off on it.
1005:
1006: =cut
1007:
1008: sub MakeLondConnection {
1009: Debug(4,"MakeLondConnection to ".GetServerHost()." on port "
1010: .GetServerPort());
1011:
1012: my $Connection = LondConnection->new(&GetServerHost(),
1013: &GetServerPort());
1014:
1015: if($Connection == undef) { # Needs to be more robust later.
1016: Log("CRITICAL","Failed to make a connection with lond.");
1017: $ConnectionRetriesLeft--;
1018: return 0; # Failure.
1019: } else {
1020: $ConnectionRetriesLeft = $ConnectionRetries; # success resets the count
1021: # The connection needs to have writability
1022: # monitored in order to send the init sequence
1023: # that starts the whole authentication/key
1024: # exchange underway.
1025: #
1026: my $Socket = $Connection->GetSocket();
1027: if($Socket == undef) {
1028: die "did not get a socket from the connection";
1029: } else {
1030: &Debug(9,"MakeLondConnection got socket: ".$Socket);
1031: }
1032:
1033:
1034: $event = Event->io(fd => $Socket,
1035: poll => 'w',
1036: cb => \&LondWritable,
1037: data => $Connection,
1038: desc => 'Connection to lond server');
1039: $ActiveConnections{$Connection} = $event;
1040:
1041: $ConnectionCount++;
1042: Debug(4, "Connection count = ".$ConnectionCount);
1043: if($ConnectionCount == 1) { # First Connection:
1044: QueueDelayed;
1045: }
1046: Log("SUCESS", "Created connection ".$ConnectionCount
1047: ." to host ".GetServerHost());
1048: return 1; # Return success.
1049: }
1050:
1051: }
1052:
1053: =pod
1054:
1055: =head2 StartRequest
1056:
1057: Starts a lond request going on a specified lond connection.
1058: parameters are:
1059:
1060: =item $Lond
1061:
1062: Connection to the lond that will send the transaction and receive the
1063: reply.
1064:
1065: =item $Client
1066:
1067: Connection to the client that is making this request We got the
1068: request from this socket, and when the request has been relayed to
1069: lond and we get a reply back from lond it will get sent to this
1070: socket.
1071:
1072: =item $Request
1073:
1074: The text of the request to send.
1075:
1076: =cut
1077:
1078: sub StartRequest {
1079: my $Lond = shift;
1080: my $Request = shift; # This is a LondTransaction.
1081:
1082: Debug(6, "StartRequest: ".$Request->getRequest());
1083:
1084: my $Socket = $Lond->GetSocket();
1085:
1086: $Request->Activate($Lond);
1087: $ActiveTransactions{$Lond} = $Request;
1088:
1089: $Lond->InitiateTransaction($Request->getRequest());
1090: $event = Event->io(fd => $Socket,
1091: poll => "w",
1092: cb => \&LondWritable,
1093: data => $Lond,
1094: desc => "lond transaction connection");
1095: $ActiveConnections{$Lond} = $event;
1096: Debug(8," Start Request made watcher data with ".$event->data."\n");
1097: }
1098:
1099: =pod
1100:
1101: =head2 QueueTransaction
1102:
1103: If there is an idle lond connection, it is put to work doing this
1104: transaction. Otherwise, the transaction is placed in the work queue.
1105: If placed in the work queue and the maximum number of connections has
1106: not yet been created, a new connection will be started. Our goal is
1107: to eventually have a sufficient number of connections that the work
1108: queue will typically be empty. parameters are:
1109:
1110: =item Socket
1111:
1112: open on the lonc client.
1113:
1114: =item Request
1115:
1116: data to send to the lond.
1117:
1118: =cut
1119:
1120: sub QueueTransaction {
1121:
1122: my $requestData = shift; # This is a LondTransaction.
1123: my $cmd = $requestData->getRequest();
1124:
1125: Debug(6,"QueueTransaction: ".$cmd);
1126:
1127: my $LondSocket = $IdleConnections->pop();
1128: if(!defined $LondSocket) { # Need to queue request.
1129: Debug(8,"Must queue...");
1130: $WorkQueue->enqueue($requestData);
1131: if($ConnectionCount < $MaxConnectionCount) {
1132: Debug(4,"Starting additional lond connection");
1133: MakeLondConnection();
1134: }
1135: } else { # Can start the request:
1136: Debug(8,"Can start...");
1137: StartRequest($LondSocket, $requestData);
1138: }
1139: }
1140:
1141: #-------------------------- Lonc UNIX socket handling ---------------------
1142:
1143: =pod
1144:
1145: =head2 ClientRequest
1146: Callback that is called when data can be read from the UNIX domain
1147: socket connecting us with an apache server process.
1148:
1149: =cut
1150:
1151: sub ClientRequest {
1152: Debug(6, "ClientRequest");
1153: my $event = shift;
1154: my $watcher = $event->w;
1155: my $socket = $watcher->fd;
1156: my $data = $watcher->data;
1157: my $thisread;
1158:
1159: Debug(9, " Watcher named: ".$watcher->desc);
1160:
1161: my $rv = $socket->recv($thisread, POSIX::BUFSIZ, 0);
1162: Debug(8, "rcv: data length = ".length($thisread)
1163: ." read =".$thisread);
1164: unless (defined $rv && length($thisread)) {
1165: # Likely eof on socket.
1166: Debug(5,"Client Socket closed on lonc for ".$RemoteHost);
1167: close($socket);
1168: $watcher->cancel();
1169: delete($ActiveClients{$socket});
1170: return;
1171: }
1172: Debug(8,"Data: ".$data." this read: ".$thisread);
1173: $data = $data.$thisread; # Append new data.
1174: $watcher->data($data);
1175: if($data =~ /(.*\n)/) { # Request entirely read.
1176: if($data eq "close_connection_exit\n") {
1177: Log("CRITICAL",
1178: "Request Close Connection ... exiting");
1179: CloseAllLondConnections();
1180: exit;
1181: }
1182: Debug(8, "Complete transaction received: ".$data);
1183: my $Transaction = LondTransaction->new($data);
1184: $Transaction->SetClient($socket);
1185: QueueTransaction($Transaction);
1186: $watcher->cancel(); # Done looking for input data.
1187: }
1188:
1189: }
1190:
1191:
1192: =pod
1193:
1194: =head2 NewClient
1195:
1196: Callback that is called when a connection is received on the unix
1197: socket for a new client of lonc. The callback is parameterized by the
1198: event.. which is a-priori assumed to be an io event, and therefore has
1199: an fd member that is the Listener socket. We Accept the connection
1200: and register a new event on the readability of that socket:
1201:
1202: =cut
1203:
1204: sub NewClient {
1205: Debug(6, "NewClient");
1206: my $event = shift; # Get the event parameters.
1207: my $watcher = $event->w;
1208: my $socket = $watcher->fd; # Get the event' socket.
1209: my $connection = $socket->accept(); # Accept the client connection.
1210: Debug(8,"Connection request accepted from "
1211: .GetPeername($connection, AF_UNIX));
1212:
1213:
1214: my $description = sprintf("Connection to lonc client %d",
1215: $ClientConnection);
1216: Debug(9, "Creating event named: ".$description);
1217: Event->io(cb => \&ClientRequest,
1218: poll => 'r',
1219: desc => $description,
1220: data => "",
1221: fd => $connection);
1222: $ActiveClients{$connection} = $ClientConnection;
1223: $ClientConnection++;
1224: }
1225:
1226: =pod
1227:
1228: =head2 GetLoncSocketPath
1229:
1230: Returns the name of the UNIX socket on which to listen for client
1231: connections.
1232:
1233: =cut
1234:
1235: sub GetLoncSocketPath {
1236: return $UnixSocketDir."/".GetServerHost();
1237: }
1238:
1239: =pod
1240:
1241: =head2 GetServerHost
1242:
1243: Returns the host whose lond we talk with.
1244:
1245: =cut
1246:
1247: sub GetServerHost {
1248: return $RemoteHost; # Setup by the fork.
1249: }
1250:
1251: =pod
1252:
1253: =head2 GetServerPort
1254:
1255: Returns the lond port number.
1256:
1257: =cut
1258:
1259: sub GetServerPort {
1260: return $perlvar{londPort};
1261: }
1262:
1263: =pod
1264:
1265: =head2 SetupLoncListener
1266:
1267: Setup a lonc listener event. The event is called when the socket
1268: becomes readable.. that corresponds to the receipt of a new
1269: connection. The event handler established will accept the connection
1270: (creating a communcations channel), that int turn will establish
1271: another event handler to subess requests.
1272:
1273: =cut
1274:
1275: sub SetupLoncListener {
1276:
1277: my $socket;
1278: my $SocketName = GetLoncSocketPath();
1279: unlink($SocketName);
1280: unless ($socket =IO::Socket::UNIX->new(Local => $SocketName,
1281: Listen => 10,
1282: Type => SOCK_STREAM)) {
1283: die "Failed to create a lonc listner socket";
1284: }
1285: Event->io(cb => \&NewClient,
1286: poll => 'r',
1287: desc => 'Lonc listener Unix Socket',
1288: fd => $socket);
1289: }
1290:
1291: =pod
1292:
1293: =head2 SignalledToDeath
1294:
1295: Called in response to a signal that causes a chid process to die.
1296:
1297: =cut
1298:
1299:
1300: sub SignalledToDeath {
1301: Debug(2,"Signalled to death!");
1302: my ($signal) = @_;
1303: chomp($signal);
1304: Log("CRITICAL", "Abnormal exit. Child $$ for $RemoteHost "
1305: ."died through "."\"$signal\"");
1306: LogPerm("F:lonc: $$ on $RemoteHost signalled to death: "
1307: ."\"$signal\"");
1308: die("Signal abnormal end");
1309: exit 0;
1310:
1311: }
1312: =head2 ChildProcess
1313:
1314: This sub implements a child process for a single lonc daemon.
1315:
1316: =cut
1317:
1318: sub ChildProcess {
1319:
1320:
1321: # For now turn off signals.
1322:
1323: $SIG{QUIT} = \&SignalledToDeath;
1324: $SIG{HUP} = IGNORE;
1325: $SIG{USR1} = IGNORE;
1326: $SIG{INT} = DEFAULT;
1327: $SIG{CHLD} = IGNORE;
1328: $SIG{__DIE__} = \&SignalledToDeath;
1329:
1330: SetupTimer();
1331:
1332: SetupLoncListener();
1333:
1334: $Event::Debuglevel = $DebugLevel;
1335:
1336: Debug(9, "Making initial lond connection for ".$RemoteHost);
1337:
1338: # Setup the initial server connection:
1339:
1340: # &MakeLondConnection(); // let first work requirest do it.
1341:
1342:
1343: Debug(9,"Entering event loop");
1344: my $ret = Event::loop(); # Start the main event loop.
1345:
1346:
1347: die "Main event loop exited!!!";
1348: }
1349:
1350: # Create a new child for host passed in:
1351:
1352: sub CreateChild {
1353: my $sigset = POSIX::SigSet->new(SIGINT);
1354: sigprocmask(SIG_BLOCK, $sigset);
1355: my $host = shift;
1356: $RemoteHost = $host;
1357: Log("CRITICAL", "Forking server for ".$host);
1358: $pid = fork;
1359: if($pid) { # Parent
1360: $ChildHash{$pid} = $RemoteHost;
1361: sigprocmask(SIG_UNBLOCK, $sigset);
1362:
1363: } else { # child.
1364: ShowStatus("Connected to ".$RemoteHost);
1365: $SIG{INT} = DEFAULT;
1366: sigprocmask(SIG_UNBLOCK, $sigset);
1367: ChildProcess; # Does not return.
1368: }
1369:
1370: }
1371: #
1372: # Parent process logic pass 1:
1373: # For each entry in the hosts table, we will
1374: # fork off an instance of ChildProcess to service the transactions
1375: # to that host. Each pid will be entered in a global hash
1376: # with the value of the key, the host.
1377: # The parent will then enter a loop to wait for process exits.
1378: # Each exit gets logged and the child gets restarted.
1379: #
1380:
1381: #
1382: # Fork and start in new session so hang-up isn't going to
1383: # happen without intent.
1384: #
1385:
1386:
1387:
1388:
1389:
1390:
1391: ShowStatus("Forming new session");
1392: my $childpid = fork;
1393: if ($childpid != 0) {
1394: sleep 4; # Give child a chacne to break to
1395: exit 0; # a new sesion.
1396: }
1397: #
1398: # Write my pid into the pid file so I can be located
1399: #
1400:
1401: ShowStatus("Parent writing pid file:");
1402: $execdir = $perlvar{'lonDaemons'};
1403: open (PIDSAVE, ">$execdir/logs/lonc.pid");
1404: print PIDSAVE "$$\n";
1405: close(PIDSAVE);
1406:
1407: if (POSIX::setsid() < 0) {
1408: print "Could not create new session\n";
1409: exit -1;
1410: }
1411:
1412: ShowStatus("Forking node servers");
1413:
1414: Log("CRITICAL", "--------------- Starting children ---------------");
1415:
1416: my $HostIterator = LondConnection::GetHostIterator;
1417: while (! $HostIterator->end()) {
1418:
1419: $hostentryref = $HostIterator->get();
1420: CreateChild($hostentryref->[0]);
1421: $HostIterator->next();
1422: }
1423: $RemoteHost = "Parent Server";
1424:
1425: # Maintain the population:
1426:
1427: ShowStatus("Parent keeping the flock");
1428:
1429: #
1430: # Set up parent signals:
1431: #
1432:
1433: $SIG{INT} = \&KillThemAll;
1434: $SIG{TERM} = \&KillThemAll;
1435: $SIG{HUP} = \&Restart;
1436:
1437: while(1) {
1438: $deadchild = wait();
1439: if(exists $ChildHash{$deadchild}) { # need to restart.
1440: $deadhost = $ChildHash{$deadchild};
1441: delete($ChildHash{$deadchild});
1442: Log("WARNING","Lost child pid= ".$deadchild.
1443: "Connected to host ".$deadhost);
1444: Log("INFO", "Restarting child procesing ".$deadhost);
1445: CreateChild($deadhost);
1446: }
1447: }
1448:
1449: =pod
1450:
1451: =head1 Restart
1452:
1453: Signal handler for HUP... all children are killed and
1454: we self restart. This is an el-cheapo way to re read
1455: the config file.
1456:
1457: =cut
1458:
1459: sub Restart {
1460: KillThemAll; # First kill all the children.
1461: Log("CRITICAL", "Restarting");
1462: my $execdir = $perlvar{'lonDaemons'};
1463: unlink("$execdir/logs/lonc.pid");
1464: exec("$execdir/lonc");
1465: }
1466:
1467: =pod
1468:
1469: =head1 KillThemAll
1470:
1471: Signal handler that kills all children by sending them a
1472: SIGINT. Responds to sigint and sigterm.
1473:
1474: =cut
1475:
1476: sub KillThemAll {
1477: Debug(2, "Kill them all!!");
1478: local($SIG{CHLD}) = 'IGNORE'; # Our children >will< die.
1479: foreach $pid (keys %ChildHash) {
1480: my $serving = $ChildHash{$pid};
1481: Debug(2, "Killing lonc for $serving pid = $pid");
1482: ShowStatus("Killing lonc for $serving pid = $pid");
1483: Log("CRITICAL", "Killing lonc for $serving pid = $pid");
1484: kill('INT', $pid);
1485: }
1486: Log("CRITICAL", "Killing the master process.");
1487: exit
1488: }
1489:
1490: =pod
1491:
1492: =head1 Theory
1493:
1494: The event class is used to build this as a single process with an
1495: event driven model. The following events are handled:
1496:
1497: =item UNIX Socket connection Received
1498:
1499: =item Request data arrives on UNIX data transfer socket.
1500:
1501: =item lond connection becomes writable.
1502:
1503: =item timer fires at 1 second intervals.
1504:
1505: All sockets are run in non-blocking mode. Timeouts managed by the timer
1506: handler prevents hung connections.
1507:
1508: Key data structures:
1509:
1510: =item RequestQueue
1511:
1512: A queue of requests received from UNIX sockets that are
1513: waiting for a chance to be forwarded on a lond connection socket.
1514:
1515: =item ActiveConnections
1516:
1517: A hash of lond connections that have transactions in process that are
1518: available to be timed out.
1519:
1520: =item ActiveTransactions
1521:
1522: A hash indexed by lond connections that contain the client reply
1523: socket for each connection that has an active transaction on it.
1524:
1525: =item IdleConnections
1526:
1527: A hash of lond connections that have no work to do. These connections
1528: can be closed if they are idle for a long enough time.
1529:
1530: =cut
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