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