Annotation of loncom/LondConnection.pm, revision 1.53.2.1

1.2       albertel    1: #   This module defines and implements a class that represents
                      2: #   a connection to a lond daemon.
                      3: #
1.53.2.1! raeburn     4: # $Id: LondConnection.pm,v 1.53 2012/10/01 11:00:43 foxr Exp $
1.2       albertel    5: #
                      6: # Copyright Michigan State University Board of Trustees
                      7: #
                      8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                      9: #
                     10: # LON-CAPA is free software; you can redistribute it and/or modify
                     11: # it under the terms of the GNU General Public License as published by
                     12: # the Free Software Foundation; either version 2 of the License, or
                     13: # (at your option) any later version.
                     14: #
                     15: # LON-CAPA is distributed in the hope that it will be useful,
                     16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     18: # GNU General Public License for more details.
                     19: #
                     20: # You should have received a copy of the GNU General Public License
                     21: # along with LON-CAPA; if not, write to the Free Software
                     22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     23: #
                     24: # /home/httpd/html/adm/gpl.txt
                     25: #
                     26: # http://www.lon-capa.org/
1.1       foxr       27: #
1.14      foxr       28: 
1.1       foxr       29: package LondConnection;
                     30: 
1.10      foxr       31: use strict;
1.1       foxr       32: use IO::Socket;
                     33: use IO::Socket::INET;
                     34: use IO::Handle;
                     35: use IO::File;
                     36: use Fcntl;
                     37: use POSIX;
                     38: use Crypt::IDEA;
1.31      foxr       39: use LONCAPA::lonlocal;
                     40: use LONCAPA::lonssl;
1.14      foxr       41: 
1.1       foxr       42: 
1.12      foxr       43: 
                     44: 
1.32      foxr       45: my $DebugLevel=0;
1.12      foxr       46: my %perlvar;
1.31      foxr       47: my $InsecureOk;
1.1       foxr       48: 
1.14      foxr       49: #
1.16      foxr       50: #  Set debugging level
                     51: #
                     52: sub SetDebug {
                     53:     $DebugLevel = shift;
                     54: }
                     55: 
                     56: #
1.14      foxr       57: #   The config read is done in this way to support the read of
                     58: #   the non-default configuration file in the
                     59: #   event we are being used outside of loncapa.
                     60: #
                     61: 
                     62: my $ConfigRead = 0;
                     63: 
1.1       foxr       64: #   Read the configuration file for apache to get the perl
1.31      foxr       65: #   variables set.
1.1       foxr       66: 
1.12      foxr       67: sub ReadConfig {
1.31      foxr       68:     Debug(8, "ReadConfig called");
                     69: 
1.14      foxr       70:     my $perlvarref = read_conf('loncapa.conf');
1.12      foxr       71:     %perlvar    = %{$perlvarref};
1.17      foxr       72:     $ConfigRead = 1;
1.12      foxr       73:     
1.31      foxr       74:     $InsecureOk = $perlvar{loncAllowInsecure};
1.15      foxr       75: }
1.1       foxr       76: 
                     77: sub Debug {
1.30      foxr       78: 
                     79:     my ($level, $message) = @_;
                     80: 
1.1       foxr       81:     if ($level < $DebugLevel) {
1.31      foxr       82: 	print STDERR ($message."\n");
1.1       foxr       83:     }
                     84: }
1.3       albertel   85: 
                     86: =pod
                     87: 
                     88: =head2 Dump
                     89: 
1.12      foxr       90: Dump the internal state of the object: For debugging purposes, to stderr.
1.3       albertel   91: 
1.1       foxr       92: =cut
                     93: 
                     94: sub Dump {
                     95:     my $self   = shift;
1.32      foxr       96:     my $level  = shift;
1.35      foxr       97:     my $now    = time;
                     98:     my $local  = localtime($now);
1.32      foxr       99:     
1.37      albertel  100:     if ($level >= $DebugLevel) {
1.32      foxr      101: 	return;
                    102:     }
                    103: 
1.35      foxr      104:     
1.10      foxr      105:     my $key;
                    106:     my $value;
1.35      foxr      107:     print STDERR "[ $local ] Dumping LondConnectionObject:\n";
1.37      albertel  108:     print STDERR join(':',caller(1))."\n";
1.1       foxr      109:     while(($key, $value) = each %$self) {
1.22      foxr      110: 	print STDERR "$key -> $value\n";
1.1       foxr      111:     }
1.23      foxr      112:     print STDERR "-------------------------------\n";
1.1       foxr      113: }
                    114: 
                    115: =pod
1.3       albertel  116: 
                    117: Local function to do a state transition.  If the state transition
                    118: callback is defined it is called with two parameters: the self and the
                    119: old state.
                    120: 
1.1       foxr      121: =cut
1.3       albertel  122: 
1.1       foxr      123: sub Transition {
1.30      foxr      124: 
                    125:     my ($self, $newstate) = @_;
                    126: 
1.1       foxr      127:     my $oldstate = $self->{State};
                    128:     $self->{State} = $newstate;
                    129:     $self->{TimeoutRemaining} = $self->{TimeoutValue};
                    130:     if($self->{TransitionCallback}) {
                    131: 	($self->{TransitionCallback})->($self, $oldstate); 
                    132:     }
                    133: }
                    134: 
1.3       albertel  135: 
1.14      foxr      136: 
1.1       foxr      137: =pod
1.3       albertel  138: 
                    139: =head2 new
                    140: 
                    141: Construct a new lond connection.
                    142: 
                    143: Parameters (besides the class name) include:
                    144: 
                    145: =item hostname
                    146: 
                    147: host the remote lond is on. This host is a host in the hosts.tab file
                    148: 
                    149: =item port
                    150: 
                    151:  port number the remote lond is listening on.
                    152: 
1.1       foxr      153: =cut
1.3       albertel  154: 
1.1       foxr      155: sub new {
1.44      albertel  156:     my ($class, $DnsName, $Port, $lonid) = @_;
1.14      foxr      157: 
                    158:     if (!$ConfigRead) {
                    159: 	ReadConfig();
                    160: 	$ConfigRead = 1;
                    161:     }
1.45      albertel  162:     &Debug(4,$class."::new( ".$DnsName.",".$Port.",".$lonid.")\n");
1.1       foxr      163: 
                    164:     # The host must map to an entry in the hosts table:
                    165:     #  We connect to the dns host that corresponds to that
                    166:     #  system and use the hostname for the encryption key 
                    167:     #  negotion.  In the objec these become the Host and
                    168:     #  LoncapaHim fields of the object respectively.
                    169:     #
1.36      albertel  170:     # if it is me use loopback for connection
1.44      albertel  171:     if ($DnsName eq &main::my_hostname()) { $DnsName="127.0.0.1"; }
                    172:     Debug(9, "Connecting to $DnsName");
1.1       foxr      173:     # Now create the object...
                    174:     my $self     = { Host               => $DnsName,
1.44      albertel  175:                      LoncapaHim         => $lonid,
1.24      foxr      176:                      Port               => $Port,
                    177:                      State              => "Initialized",
1.31      foxr      178: 		     AuthenticationMode => "",
1.24      foxr      179:                      TransactionRequest => "",
                    180:                      TransactionReply   => "",
1.39      albertel  181:                      NextRequest        => "",
1.24      foxr      182:                      InformReadable     => 0,
                    183:                      InformWritable     => 0,
                    184:                      TimeoutCallback    => undef,
                    185:                      TransitionCallback => undef,
                    186:                      Timeoutable        => 0,
1.49      raeburn   187:                      TimeoutValue       => 30,
1.24      foxr      188:                      TimeoutRemaining   => 0,
1.31      foxr      189: 		     LocalKeyFile       => "",
1.24      foxr      190:                      CipherKey          => "",
                    191:                      LondVersion        => "Unknown",
1.52      foxr      192:                      Cipher             => undef,
                    193: 		     ClientData         => undef};
1.1       foxr      194:     bless($self, $class);
                    195:     unless ($self->{Socket} = IO::Socket::INET->new(PeerHost => $self->{Host},
1.27      foxr      196: 					       PeerPort => $self->{Port},
                    197: 					       Type     => SOCK_STREAM,
                    198: 					       Proto    => "tcp",
                    199: 					       Timeout  => 3)) {
1.36      albertel  200: 	Debug(8, "Error? \n$@ \n$!");
1.1       foxr      201: 	return undef;		# Inidicates the socket could not be made.
                    202:     }
1.31      foxr      203:     my $socket = $self->{Socket}; # For local use only.
1.51      foxr      204:     $socket->sockopt(SO_KEEPALIVE, 1); # Turn on keepalive probes when idle.
1.33      foxr      205:     #  If we are local, we'll first try local auth mode, otherwise, we'll try
                    206:     #  the ssl auth mode:
1.31      foxr      207: 
                    208:     my $key;
                    209:     my $keyfile;
1.36      albertel  210:     if ($DnsName eq '127.0.0.1') {
1.31      foxr      211: 	$self->{AuthenticationMode} = "local";
                    212: 	($key, $keyfile)         = lonlocal::CreateKeyFile();
                    213: 	Debug(8, "Local key: $key, stored in $keyfile");
                    214: 	   
                    215: 	#  If I can't make the key file fall back to insecure if 
                    216: 	#  allowed...else give up right away.
                    217: 
                    218: 	if(!(defined $key) || !(defined $keyfile)) {
                    219: 	    if($InsecureOk) {
                    220: 		$self->{AuthenticationMode} = "insecure";
                    221: 		$self->{TransactionRequest} = "init\n";
                    222: 	    } 
                    223: 	    else {
                    224: 		$socket->close;
                    225: 		return undef;
                    226: 	    }
                    227: 	}
                    228: 	$self->{TransactionRequest} = "init:local:$keyfile\n";
                    229: 	Debug(9, "Init string is init:local:$keyfile");
                    230: 	if(!$self->CreateCipher($key)) { # Nothing's going our way...
                    231: 	    $socket->close;
                    232: 	    return undef;
                    233: 	}
                    234: 
1.42      albertel  235:     } else {
1.33      foxr      236: 	#  Remote peer:  I'd like to do ssl, but if my host key or certificates
                    237: 	#  are not all installed, my only choice is insecure, if that's 
                    238: 	#  allowed:
                    239: 
                    240: 	my ($ca, $cert) = lonssl::CertificateFile;
                    241: 	my $sslkeyfile  = lonssl::KeyFile;
                    242: 
                    243: 	if((defined $ca)  && (defined $cert) && (defined $sslkeyfile)) {
                    244: 
                    245: 	    $self->{AuthenticationMode} = "ssl";
1.47      raeburn   246: 	    $self->{TransactionRequest} = "init:ssl:$perlvar{'lonVersion'}\n";
1.33      foxr      247: 	} else {
                    248: 	    if($InsecureOk) {		# Allowed to do insecure:
                    249: 		$self->{AuthenticationMode} = "insecure";
1.47      raeburn   250: 		$self->{TransactionRequest} = "init::$perlvar{'lonVersion'}\n";
1.33      foxr      251: 	    }
                    252: 	    else {		# Not allowed to do insecure...
                    253: 		$socket->close;
                    254: 		return undef;
                    255: 	    }
                    256: 	}
1.31      foxr      257:     }
                    258: 
1.1       foxr      259:     #
                    260:     # We're connected.  Set the state, and the events we'll accept:
                    261:     #
                    262:     $self->Transition("Connected");
                    263:     $self->{InformWritable}     = 1;    # When  socket is writable we send init
1.9       foxr      264:     $self->{Timeoutable}        = 1;    # Timeout allowed during startup negotiation. 
1.31      foxr      265: 
1.1       foxr      266:     
                    267:     #
                    268:     # Set socket to nonblocking I/O.
                    269:     #
1.31      foxr      270:     my $flags    = fcntl($socket, F_GETFL,0);
                    271:     if(!$flags) {
1.1       foxr      272: 	$socket->close;
                    273: 	return undef;
                    274:     }
1.31      foxr      275:     if(!fcntl($socket, F_SETFL, $flags | O_NONBLOCK)) {
1.1       foxr      276: 	$socket->close;
                    277: 	return undef;
                    278:     }
                    279: 
                    280:     # return the object :
                    281: 
1.31      foxr      282:     Debug(9, "Initial object state: ");
1.32      foxr      283:     $self->Dump(9);
1.31      foxr      284: 
1.1       foxr      285:     return $self;
                    286: }
1.3       albertel  287: 
1.1       foxr      288: =pod
1.3       albertel  289: 
                    290: =head2 Readable
                    291: 
                    292: This member should be called when the Socket becomes readable.  Until
                    293: the read completes, action is state independet. Data are accepted into
                    294: the TransactionReply until a newline character is received.  At that
                    295: time actionis state dependent:
                    296: 
                    297: =item Connected
                    298: 
                    299: in this case we received challenge, the state changes to
                    300: ChallengeReceived, and we initiate a send with the challenge response.
                    301: 
                    302: =item ReceivingReply
                    303: 
                    304: In this case a reply has been received for a transaction, the state
                    305: goes to Idle and we disable write and read notification.
                    306: 
                    307: =item ChallengeReeived
                    308: 
                    309: we just got what should be an ok\n and the connection can now handle
                    310: transactions.
1.1       foxr      311: 
                    312: =cut
1.3       albertel  313: 
1.1       foxr      314: sub Readable {
                    315:     my $self    = shift;
                    316:     my $socket  = $self->{Socket};
                    317:     my $data    = '';
1.27      foxr      318:     my $rv;
1.31      foxr      319:     my $ConnectionMode = $self->{AuthenticationMode};
                    320: 
1.27      foxr      321:     if ($socket) {
                    322: 	eval {
                    323: 	    $rv = $socket->recv($data, POSIX::BUFSIZ, 0);
                    324: 	}
                    325:     } else {
                    326: 	$self->Transition("Disconnected");
                    327: 	return -1;
                    328:     }
1.1       foxr      329:     my $errno   = $! + 0;	             # Force numeric context.
                    330: 
1.8       foxr      331:     unless (defined($rv) && length $data) {# Read failed,
1.1       foxr      332: 	if(($errno == POSIX::EWOULDBLOCK)   ||
                    333: 	   ($errno == POSIX::EAGAIN)        ||
1.8       foxr      334: 	   ($errno == POSIX::EINTR)) {
1.1       foxr      335: 	    return 0;
                    336: 	}
                    337: 
                    338: 	# Connection likely lost.
                    339: 	&Debug(4, "Connection lost");
                    340: 	$self->{TransactionRequest} = '';
                    341: 	$socket->close();
                    342: 	$self->Transition("Disconnected");
                    343: 	return -1;
                    344:     }
1.53      foxr      345:     # If we actually got data, reset the timeout.
                    346: 
                    347:     if (length $data) {
                    348: 	$self->{TimeoutRemaining}   = $self->{TimeoutValue}; # getting data resets the timeout period.
                    349:     }
1.1       foxr      350:     #  Append the data to the buffer.  And figure out if the read is done:
                    351: 
                    352:     &Debug(9,"Received from host: ".$data);
                    353:     $self->{TransactionReply} .= $data;
1.29      albertel  354:     if($self->{TransactionReply} =~ m/\n$/) {
1.1       foxr      355: 	&Debug(8,"Readable End of line detected");
1.31      foxr      356: 	
                    357: 
1.1       foxr      358: 	if ($self->{State}  eq "Initialized") { # We received the challenge:
1.31      foxr      359: 	    #   Our init was replied to. What happens next depends both on
                    360: 	    #  the actual init we sent (AuthenticationMode member data)
                    361: 	    #  and the response:
                    362: 	    #     AuthenticationMode == local:
                    363: 	    #       Response ok:   The key has been exchanged and
                    364: 	    #                      the key file destroyed. We can jump
                    365: 	    #                      into setting the host and requesting the
                    366: 	    #                      Later we'll also bypass key exchange.
                    367: 	    #       Response digits: 
                    368: 	    #                      Old style lond. Delete the keyfile.
                    369: 	    #                      If allowed fall back to insecure mode.
                    370: 	    #                      else close connection and fail.
                    371: 	    #       Response other:
                    372: 	    #                      Failed local auth 
                    373: 	    #                      Close connection and fail.
                    374: 	    #
                    375: 	    #    AuthenticationMode == ssl:
                    376: 	    #        Response ok:ssl
                    377: 	    #        Response digits:
                    378: 	    #        Response other:
                    379: 	    #    Authentication mode == insecure
                    380: 	    #        Response digits
                    381: 	    #        Response other:
                    382: 	    
                    383: 	    my $Response = $self->{TransactionReply};
                    384: 	    if($ConnectionMode eq "local") {
                    385: 		if($Response =~ /^ok:local/) { #  Good local auth.
                    386: 		    $self->ToVersionRequest();
                    387: 		    return 0;
                    388: 		}
                    389: 		elsif ($Response =~/^[0-9]+/) {	# Old style lond.
                    390: 		    return $self->CompleteInsecure();
                    391: 
                    392: 		}
                    393: 		else {		                # Complete flop
                    394: 		    &Debug(3, "init:local : unrecognized reply");
                    395: 		    $self->Transition("Disconnected");
                    396: 		    $socket->close;
                    397: 		    return -1;
                    398: 		}
                    399: 	    }
                    400: 	    elsif ($ConnectionMode eq "ssl") {
                    401: 		if($Response =~ /^ok:ssl/) {     # Good ssl...
                    402: 		    if($self->ExchangeKeysViaSSL()) { # Success skip to vsn stuff
                    403: 			# Need to reset to non blocking:
                    404: 
                    405: 			my $flags = fcntl($socket, F_GETFL, 0);
                    406: 			fcntl($socket, F_SETFL, $flags | O_NONBLOCK);
                    407: 			$self->ToVersionRequest();
                    408: 			return 0;
                    409: 		    }
                    410: 		    else {	         # Failed in ssl exchange.
                    411: 			&Debug(3,"init:ssl failed key negotiation!");
                    412: 			$self->Transition("Disconnected");
                    413: 			$socket->close;
                    414: 			return -1;
                    415: 		    }
                    416: 		} 
                    417: 		elsif ($Response =~ /^[0-9]+/) { # Old style lond.
                    418: 		    return $self->CompleteInsecure();
                    419: 		}
                    420: 		else {		                 # Complete flop
                    421: 		}
                    422: 	    }
                    423: 	    elsif ($ConnectionMode eq "insecure") {
                    424: 		if($self->{TransactionReply} eq "refused\n") {	# Remote doesn't have
                    425: 		    
                    426: 		    $self->Transition("Disconnected"); # in host tables.
                    427: 		    $socket->close();
                    428: 		    return -1;
                    429: 
                    430: 		}
                    431: 		return $self->CompleteInsecure();
                    432: 	    }
                    433: 	    else {
                    434: 		&Debug(1,"Authentication mode incorrect");
                    435: 		die "BUG!!! LondConnection::Readable invalid authmode";
1.1       foxr      436: 	    }
1.27      foxr      437: 
1.31      foxr      438: 
1.28      albertel  439: 	}  elsif ($self->{State} eq "ChallengeReplied") {
                    440: 	    if($self->{TransactionReply} ne "ok\n") {
                    441: 		$self->Transition("Disconnected");
                    442: 		$socket->close();
                    443: 		return -1;
                    444: 	    }
1.31      foxr      445: 	    $self->ToVersionRequest();
1.28      albertel  446: 	    return 0;
1.31      foxr      447: 
1.28      albertel  448: 	} elsif ($self->{State} eq "ReadingVersionString") {
1.38      albertel  449: 	    chomp($self->{TransactionReply});
                    450: 	    $self->{LondVersion}       = $self->{TransactionReply};
1.28      albertel  451: 	    $self->Transition("SetHost");
                    452: 	    $self->{InformReadable}    = 0;
                    453: 	    $self->{InformWritable}    = 1;
                    454: 	    my $peer = $self->{LoncapaHim};
                    455: 	    $self->{TransactionRequest}= "sethost:$peer\n";
                    456: 	    return 0;
1.24      foxr      457: 	} elsif ($self->{State} eq "HostSet") { # should be ok.
1.28      albertel  458: 	    if($self->{TransactionReply} ne "ok\n") {
                    459: 		$self->Transition("Disconnected");
                    460: 		$socket->close();
                    461: 		return -1;
                    462: 	    }
1.31      foxr      463: 	    #  If the auth mode is insecure we must still
                    464: 	    #  exchange session keys. Otherwise,
                    465: 	    #  we can just transition to idle.
                    466: 
                    467: 	    if($ConnectionMode eq "insecure") {
                    468: 		$self->Transition("RequestingKey");
                    469: 		$self->{InformReadable}  = 0;
                    470: 		$self->{InformWritable}  = 1;
                    471: 		$self->{TransactionRequest} = "ekey\n";
                    472: 		return 0;
                    473: 	    }
                    474: 	    else {
                    475: 		$self->ToIdle();
                    476: 		return 0;
                    477: 	    }
1.1       foxr      478: 	} elsif ($self->{State}  eq "ReceivingKey") {
                    479: 	    my $buildkey = $self->{TransactionReply};
                    480: 	    my $key = $self->{LoncapaHim}.$perlvar{'lonHostID'};
                    481: 	    $key=~tr/a-z/A-Z/;
                    482: 	    $key=~tr/G-P/0-9/;
                    483: 	    $key=~tr/Q-Z/0-9/;
1.31      foxr      484: 	    $key =$key.$buildkey.$key.$buildkey.$key.$buildkey;
                    485: 	    $key               = substr($key,0,32);
                    486: 	    if(!$self->CreateCipher($key)) {
1.1       foxr      487: 		$self->Transition("Disconnected");
                    488: 		$socket->close();
                    489: 		return -1;
                    490: 	    } else {
1.31      foxr      491: 		$self->ToIdle();
1.1       foxr      492: 		return 0;
                    493: 	    }
                    494: 	} elsif ($self->{State}  eq "ReceivingReply") {
                    495: 
                    496: 	    # If the data are encrypted, decrypt first.
                    497: 
                    498: 	    my $answer = $self->{TransactionReply};
                    499: 	    if($answer =~ /^enc\:/) {
                    500: 		$answer = $self->Decrypt($answer);
1.34      foxr      501: 		$self->{TransactionReply} = "$answer\n";
1.1       foxr      502: 	    }
1.39      albertel  503: 	    # if we have a NextRequest do it immeadiately
                    504: 	    if ($self->{NextRequest}) {
                    505: 		$self->{TransactionRequest} = $self->{NextRequest};
                    506: 		undef( $self->{NextRequest} );
                    507: 		$self->{TransactionReply}   = "";
                    508: 		$self->{InformWritable}     = 1;
                    509: 		$self->{InformReadable}     = 0;
                    510: 		$self->{Timeoutable}        = 1;
                    511: 		$self->Transition("SendingRequest");
                    512: 		return 0;
                    513: 	    } else {
1.1       foxr      514: 	    # finish the transaction
                    515: 
1.39      albertel  516: 		$self->ToIdle();
                    517: 		return 0;
                    518: 	    }
1.1       foxr      519: 	} elsif ($self->{State} eq "Disconnected") { # No connection.
                    520: 	    return -1;
                    521: 	} else {			# Internal error: Invalid state.
                    522: 	    $self->Transition("Disconnected");
                    523: 	    $socket->close();
                    524: 	    return -1;
                    525: 	}
                    526:     }
                    527: 
                    528:     return 0;
1.27      foxr      529:     
1.1       foxr      530: }
                    531: 
                    532: 
                    533: =pod
1.3       albertel  534: 
                    535: This member should be called when the Socket becomes writable.
                    536: 
                    537: The action is state independent. An attempt is made to drain the
                    538: contents of the TransactionRequest member.  Once this is drained, we
                    539: mark the object as waiting for readability.
1.1       foxr      540: 
                    541: Returns  0 if successful, or -1 if not.
1.3       albertel  542: 
1.1       foxr      543: =cut
                    544: sub Writable {
                    545:     my $self     = shift;		# Get reference to the object.
                    546:     my $socket   = $self->{Socket};
1.26      albertel  547:     my $nwritten;
                    548:     if ($socket) {
                    549: 	eval {
                    550: 	    $nwritten = $socket->send($self->{TransactionRequest}, 0);
                    551: 	}
1.27      foxr      552:     } else {
                    553: 	# For whatever reason, there's no longer a socket left.
                    554: 
                    555: 
                    556: 	$self->Transition("Disconnected");
                    557: 	return -1;
1.26      albertel  558:     }
1.1       foxr      559:     my $errno    = $! + 0;
                    560:     unless (defined $nwritten) {
                    561: 	if($errno != POSIX::EINTR) {
                    562: 	    $self->Transition("Disconnected");
                    563: 	    return -1;
                    564: 	}
                    565:       
                    566:     }
1.10      foxr      567:     if (($nwritten >= 0)                        ||
1.1       foxr      568:         ($errno == POSIX::EWOULDBLOCK)    ||
                    569: 	($errno == POSIX::EAGAIN)         ||
                    570: 	($errno == POSIX::EINTR)          ||
                    571: 	($errno ==  0)) {
1.50      foxr      572: 	$self->{TimeoutRemaining} = $self->{TimeoutValue};
1.1       foxr      573: 	substr($self->{TransactionRequest}, 0, $nwritten) = ""; # rmv written part
1.50      foxr      574: 	if(length $self->{TransactionRequest} == 0) {
                    575: 	    $self->{InformWritable} = 0;
                    576: 	    $self->{InformReadable} = 1;
                    577: 	    $self->{TransactionReply} = '';
                    578: 	    #
                    579: 	    # Figure out the next state:
                    580: 	    #
                    581: 	    if($self->{State} eq "Connected") {
                    582: 		$self->Transition("Initialized");
                    583: 	    } elsif($self->{State} eq "ChallengeReceived") {
                    584: 		$self->Transition("ChallengeReplied");
                    585: 	    } elsif($self->{State} eq "RequestingVersion") {
                    586: 		$self->Transition("ReadingVersionString");
                    587: 	    } elsif ($self->{State} eq "SetHost") {
                    588: 		$self->Transition("HostSet");
                    589: 	    } elsif($self->{State} eq "RequestingKey") {
                    590: 		$self->Transition("ReceivingKey");
1.24      foxr      591: #            $self->{InformWritable} = 0;
                    592: #            $self->{InformReadable} = 1;
                    593: #            $self->{TransactionReply} = '';
1.50      foxr      594: 	    } elsif ($self->{State} eq "SendingRequest") {
                    595: 		$self->Transition("ReceivingReply");
                    596: 		$self->{TimeoutRemaining} = $self->{TimeoutValue};
                    597: 	    } elsif ($self->{State} eq "Disconnected") {
                    598: 		return -1;
                    599: 	    }
                    600: 	    return 0;
                    601: 	}
                    602:     } else {			# The write failed (e.g. partner disconnected).
                    603: 	$self->Transition("Disconnected");
                    604: 	$socket->close();
                    605: 	return -1;
                    606:     }
                    607:     
1.1       foxr      608: }
                    609: =pod
1.3       albertel  610: 
                    611: =head2 Tick
                    612: 
1.1       foxr      613:    Tick is called every time unit by the event framework.  It
1.3       albertel  614: 
                    615: =item 1 decrements the remaining timeout.
                    616: 
                    617: =item 2 If the timeout is zero, calls TimedOut indicating that the current operation timed out.
1.1       foxr      618: 
                    619: =cut
                    620:     
                    621: sub Tick {
                    622:     my $self = shift;
                    623:     $self->{TimeoutRemaining}--;
                    624:     if ($self->{TimeoutRemaining} < 0) {
                    625: 	$self->TimedOut();
                    626:     }
                    627: }
1.3       albertel  628: 
1.1       foxr      629: =pod
                    630: 
1.3       albertel  631: =head2 TimedOut
                    632: 
                    633: called on a timeout.  If the timeout callback is defined, it is called
                    634: with $self as its parameters.
                    635: 
                    636: =cut
                    637: 
1.1       foxr      638: sub TimedOut  {
                    639: 
                    640:     my $self = shift;
                    641:     if($self->{TimeoutCallback}) {
                    642: 	my $callback = $self->{TimeoutCallback};
                    643: 	my @args = ( $self);
                    644: 	&$callback(@args);
                    645:     }
                    646: }
1.3       albertel  647: 
1.1       foxr      648: =pod
1.3       albertel  649: 
                    650: =head2 InitiateTransaction
                    651: 
                    652: Called to initiate a transaction.  A transaction can only be initiated
                    653: when the object is idle... otherwise an error is returned.  A
                    654: transaction consists of a request to the server that will have a
                    655: reply.  This member sets the request data in the TransactionRequest
                    656: member, makes the state SendingRequest and sets the data to allow a
                    657: timout, and to request writability notification.
                    658: 
1.1       foxr      659: =cut
1.3       albertel  660: 
1.1       foxr      661: sub InitiateTransaction {
1.30      foxr      662: 
                    663:     my ($self, $data) = @_;
1.1       foxr      664: 
1.4       foxr      665:     Debug(1, "initiating transaction: ".$data);
1.1       foxr      666:     if($self->{State} ne "Idle") {
1.4       foxr      667: 	Debug(0," .. but not idle here\n");
1.1       foxr      668: 	return -1;		# Error indicator.
                    669:     }
                    670:     # if the transaction is to be encrypted encrypt the data:
1.39      albertel  671:     (my $sethost, my $server,$data)=split(/:/,$data,3);
1.1       foxr      672: 
                    673:     if($data =~ /^encrypt\:/) {
                    674: 	$data = $self->Encrypt($data);
                    675:     }
                    676: 
                    677:     # Setup the trasaction
1.39      albertel  678:     # currently no version of lond supports inlining the sethost
1.40      albertel  679:     if ($self->PeerVersion() <= 321) {
1.39      albertel  680: 	if ($server ne $self->{LoncapaHim}) {
                    681: 	    $self->{NextRequest}        = $data;
                    682: 	    $self->{TransactionRequest} = "$sethost:$server\n";
                    683: 	    $self->{LoncapaHim}         = $server;
                    684: 	} else {
                    685: 	    $self->{TransactionRequest}        = $data;
                    686: 	}
                    687:     } else {
1.40      albertel  688: 	$self->{LoncapaHim}         = $server;
1.39      albertel  689: 	$self->{TransactionRequest} = "$sethost:$server:$data";
                    690:     }
1.1       foxr      691:     $self->{TransactionReply}   = "";
                    692:     $self->{InformWritable}     = 1;
                    693:     $self->{InformReadable}     = 0;
                    694:     $self->{Timeoutable}        = 1;
                    695:     $self->{TimeoutRemaining}   = $self->{TimeoutValue};
                    696:     $self->Transition("SendingRequest");
                    697: }
                    698: 
                    699: 
                    700: =pod
1.3       albertel  701: 
                    702: =head2 SetStateTransitionCallback
                    703: 
                    704: Sets a callback for state transitions.  Returns a reference to any
                    705: prior established callback, or undef if there was none:
                    706: 
1.1       foxr      707: =cut
1.3       albertel  708: 
1.1       foxr      709: sub SetStateTransitionCallback {
                    710:     my $self        = shift;
                    711:     my $oldCallback = $self->{TransitionCallback};
                    712:     $self->{TransitionCallback} = shift;
                    713:     return $oldCallback;
                    714: }
1.3       albertel  715: 
1.1       foxr      716: =pod
1.3       albertel  717: 
                    718: =head2 SetTimeoutCallback
                    719: 
                    720: Sets the timeout callback.  Returns a reference to any prior
                    721: established callback or undef if there was none.
                    722: 
1.1       foxr      723: =cut
1.3       albertel  724: 
1.1       foxr      725: sub SetTimeoutCallback {
1.30      foxr      726: 
                    727:     my ($self, $callback) = @_;
                    728: 
1.1       foxr      729:     my $oldCallback          = $self->{TimeoutCallback};
                    730:     $self->{TimeoutCallback} = $callback;
                    731:     return $oldCallback;
                    732: }
                    733: 
                    734: =pod
1.3       albertel  735: 
1.5       foxr      736: =head2 Shutdown:
                    737: 
                    738: Shuts down the socket.
                    739: 
                    740: =cut
                    741: 
                    742: sub Shutdown {
                    743:     my $self = shift;
                    744:     my $socket = $self->GetSocket();
1.20      albertel  745:     Debug(5,"socket is -$socket-");
                    746:     if ($socket) {
                    747: 	# Ask lond to exit too.  Non blocking so
                    748: 	# there is no cost for failure.
                    749: 	eval {
                    750: 	    $socket->send("exit\n", 0);
                    751: 	    $socket->shutdown(2);
                    752: 	}
                    753:     }
1.50      foxr      754:     $self->{Timeoutable}   = 0;	# Shutdown sockets can't timeout.
1.5       foxr      755: }
                    756: 
                    757: =pod
                    758: 
1.3       albertel  759: =head2 GetState
                    760: 
                    761: selector for the object state.
                    762: 
1.1       foxr      763: =cut
1.3       albertel  764: 
1.1       foxr      765: sub GetState {
                    766:     my $self = shift;
                    767:     return $self->{State};
                    768: }
1.3       albertel  769: 
1.1       foxr      770: =pod
1.3       albertel  771: 
                    772: =head2 GetSocket
                    773: 
                    774: selector for the object socket.
                    775: 
1.1       foxr      776: =cut
1.3       albertel  777: 
1.1       foxr      778: sub GetSocket {
                    779:     my $self  = shift;
                    780:     return $self->{Socket};
                    781: }
1.3       albertel  782: 
1.5       foxr      783: 
1.1       foxr      784: =pod
1.3       albertel  785: 
                    786: =head2 WantReadable
                    787: 
                    788: Return the state of the flag that indicates the object wants to be
                    789: called when readable.
                    790: 
1.1       foxr      791: =cut
1.3       albertel  792: 
1.1       foxr      793: sub WantReadable {
                    794:     my   $self = shift;
                    795: 
                    796:     return $self->{InformReadable};
                    797: }
1.3       albertel  798: 
1.1       foxr      799: =pod
1.3       albertel  800: 
                    801: =head2 WantWritable
                    802: 
                    803: Return the state of the flag that indicates the object wants write
                    804: notification.
                    805: 
1.1       foxr      806: =cut
1.3       albertel  807: 
1.1       foxr      808: sub WantWritable {
                    809:     my $self = shift;
                    810:     return $self->{InformWritable};
                    811: }
1.3       albertel  812: 
1.1       foxr      813: =pod
1.3       albertel  814: 
                    815: =head2 WantTimeout
                    816: 
                    817: return the state of the flag that indicates the object wants to be
                    818: informed of timeouts.
                    819: 
1.1       foxr      820: =cut
1.3       albertel  821: 
1.1       foxr      822: sub WantTimeout {
                    823:     my $self = shift;
                    824:     return $self->{Timeoutable};
                    825: }
                    826: 
                    827: =pod
1.3       albertel  828: 
                    829: =head2 GetReply
                    830: 
                    831: Returns the reply from the last transaction.
                    832: 
1.1       foxr      833: =cut
1.3       albertel  834: 
1.1       foxr      835: sub GetReply {
                    836:     my $self = shift;
                    837:     return $self->{TransactionReply};
                    838: }
                    839: 
                    840: =pod
1.3       albertel  841: 
                    842: =head2 Encrypt
                    843: 
                    844: Returns the encrypted version of the command string.
                    845: 
                    846: The command input string is of the form:
                    847: 
1.1       foxr      848:   encrypt:command
1.3       albertel  849: 
                    850: The output string can be directly sent to lond as it is of the form:
                    851: 
1.1       foxr      852:   enc:length:<encodedrequest>
1.3       albertel  853: 
1.1       foxr      854: =cut
1.3       albertel  855: 
1.1       foxr      856: sub Encrypt {
1.30      foxr      857:     
                    858:     my ($self, $request) = @_;
1.1       foxr      859: 
                    860:    
                    861:     # Split the encrypt: off the request and figure out it's length.
                    862:     # the cipher works in blocks of 8 bytes.
                    863: 
                    864:     my $cmd = $request;
                    865:     $cmd    =~ s/^encrypt\://;	# strip off encrypt:
                    866:     chomp($cmd);		# strip off trailing \n
                    867:     my     $length=length($cmd);	# Get the string length.
                    868:     $cmd .= "         ";	# Pad with blanks so we can fill out a block.
                    869: 
                    870:     # encrypt the request in 8 byte chunks to create the encrypted
                    871:     # output request.
                    872: 
                    873:     my $Encoded = '';
                    874:     for(my $index = 0; $index <= $length; $index += 8) {
                    875: 	$Encoded .= 
                    876: 	    unpack("H16", 
                    877: 		   $self->{Cipher}->encrypt(substr($cmd, 
                    878: 						   $index, 8)));
                    879:     }
                    880: 
                    881:     # Build up the answer as enc:length:$encrequest.
                    882: 
                    883:     $request = "enc:$length:$Encoded\n";
                    884:     return $request;
                    885:     
                    886:     
                    887: }
1.3       albertel  888: 
                    889: =pod
                    890: 
                    891: =head2 Decrypt
                    892: 
                    893: Decrypt a response from the server.  The response is in the form:
                    894: 
                    895:  enc:<length>:<encrypted data>
                    896: 
1.1       foxr      897: =cut
1.3       albertel  898: 
1.1       foxr      899: sub Decrypt {
1.30      foxr      900: 
                    901:     my ($self, $encrypted) = @_;
1.1       foxr      902: 
                    903:     #  Bust up the response into length, and encryptedstring:
                    904: 
                    905:     my ($enc, $length, $EncryptedString) = split(/:/,$encrypted);
                    906:     chomp($EncryptedString);
                    907: 
                    908:     # Decode the data in 8 byte blocks.  The string is encoded
                    909:     # as hex digits so there are two characters per byte:
                    910: 
1.10      foxr      911:     my $decrypted = "";
1.1       foxr      912:     for(my $index = 0; $index < length($EncryptedString);
                    913: 	$index += 16) {
                    914: 	$decrypted .= $self->{Cipher}->decrypt(
                    915: 				    pack("H16",
                    916: 					 substr($EncryptedString,
                    917: 						$index, 
                    918: 						16)));
                    919:     }
                    920:     #  the answer may have trailing pads to fill out a block.
                    921:     #  $length tells us the actual length of the decrypted string:
                    922: 
                    923:     $decrypted = substr($decrypted, 0, $length);
1.34      foxr      924:     Debug(9, "Decrypted $EncryptedString to $decrypted");
1.1       foxr      925: 
                    926:     return $decrypted;
                    927: 
                    928: }
1.31      foxr      929: # ToIdle
                    930: #     Called to transition to idle... done enough it's worth subbing
                    931: #     off to ensure it's always done right!!
                    932: #
                    933: sub ToIdle {
                    934:     my $self   = shift;
                    935: 
                    936:     $self->Transition("Idle");
                    937:     $self->{InformWritiable} = 0;
                    938:     $self->{InformReadable}  = 0;
                    939:     $self->{Timeoutable}     = 0;
                    940: }
                    941: 
                    942: #  ToVersionRequest
                    943: #    Called to transition to "RequestVersion"  also done a few times
                    944: #    so worth subbing out.
                    945: #
                    946: sub ToVersionRequest {
                    947:     my $self   = shift;
                    948:     
                    949:     $self->Transition("RequestingVersion");
                    950:     $self->{InformReadable}   = 0;
                    951:     $self->{InformWritable}   = 1;
                    952:     $self->{TransactionRequest} = "version\n";
                    953:     
                    954: }
                    955: #
                    956: #  CreateCipher
                    957: #    Given a cipher key stores the key in the object context,
                    958: #    creates the cipher object, (stores that in object context),
                    959: #    This is done a couple of places, so it's worth factoring it out.
                    960: #
                    961: # Parameters:
                    962: #    (self)
                    963: #    key - The Cipher key.
                    964: #
                    965: # Returns:
                    966: #    0   - Failure to create IDEA cipher.
                    967: #    1   - Success.
                    968: #
                    969: sub CreateCipher {
                    970:     my ($self, $key)   = @_;	# According to coding std.
                    971: 
                    972:     $self->{CipherKey} = $key; # Save the text key...
                    973:     my $packedkey = pack ("H32", $key);
                    974:     my $cipher            = new IDEA $packedkey;
                    975:     if($cipher) {
                    976: 	$self->{Cipher} = $cipher;
                    977: 	Debug("Cipher created  dumping socket: ");
1.32      foxr      978: 	$self->Dump(9);
1.31      foxr      979: 	return 1;
                    980:     }
                    981:     else {
                    982: 	return 0;
                    983:     }
                    984: }
                    985: # ExchangeKeysViaSSL
                    986: #     Called to do cipher key exchange via SSL.
                    987: #     The socket is promoted to an SSL socket. If that's successful,
                    988: #     we read out cipher key through the socket and create an IDEA
                    989: #     cipher object.
                    990: # Parameters:
                    991: #    (self)
                    992: # Returns:
                    993: #      true    - Success.
                    994: #      false   - Failure.
                    995: #
                    996: # Assumptions:
                    997: #  1.   The ssl session setup has timeout logic built in so we don't
                    998: #     have to worry about DOS attacks at that stage.
                    999: #  2.   If the ssl session gets set up we are talking to a legitimate
                   1000: #     lond so again we don't have to worry about DOS attacks.
                   1001: #  All this allows us just to call 
                   1002: sub ExchangeKeysViaSSL {
                   1003:     my $self   = shift;
                   1004:     my $socket = $self->{Socket};
                   1005: 
                   1006:     #  Get our signed certificate, the certificate authority's 
                   1007:     #  certificate and our private key file.  All of these
                   1008:     #  are needed to create the ssl connection.
                   1009: 
                   1010:     my ($SSLCACertificate,
                   1011: 	$SSLCertificate) = lonssl::CertificateFile();
                   1012:     my $SSLKey             = lonssl::KeyFile();
                   1013: 
                   1014:     #  Promote our connection to ssl and read the key from lond.
                   1015: 
                   1016:     my $SSLSocket = lonssl::PromoteClientSocket($socket,
                   1017: 						$SSLCACertificate,
                   1018: 						$SSLCertificate,
                   1019: 						$SSLKey);
                   1020:     if(defined $SSLSocket) {
                   1021: 	my $key  = <$SSLSocket>;
                   1022: 	lonssl::Close($SSLSocket);
                   1023: 	if($key) {
                   1024: 	    chomp($key);	# \n is not part of the key.
                   1025: 	    return $self->CreateCipher($key);
                   1026: 	} 
                   1027: 	else {
                   1028: 	    Debug(3, "Failed to read ssl key");
                   1029: 	    return 0;
                   1030: 	}
                   1031:     }
                   1032:     else {
                   1033: 	# Failed!!
                   1034: 	Debug(3, "Failed to negotiate SSL connection!");
                   1035: 	return 0;
                   1036:     }
                   1037:     # should not get here
                   1038:     return 0;
                   1039: 
                   1040: }
                   1041: 
                   1042: 
                   1043: 
                   1044: #
                   1045: #  CompleteInsecure:
                   1046: #      This function is called to initiate the completion of
                   1047: #      insecure challenge response negotiation.
                   1048: #      To do this, we copy the challenge string to the transaction
                   1049: #      request, flip to writability and state transition to 
                   1050: #      ChallengeReceived..
                   1051: #      All this is only possible if InsecureOk is true.
                   1052: # Parameters:
                   1053: #      (self)    - This object's context hash.
                   1054: #  Return:
                   1055: #      0   - Ok to transition.
                   1056: #     -1   - Not ok to transition (InsecureOk not ok).
                   1057: #
                   1058: sub CompleteInsecure {
                   1059:     my $self = shift;
                   1060:     if($InsecureOk) {
                   1061: 	$self->{AuthenticationMode} = "insecure";
                   1062: 	&Debug(8," Transition out of Initialized:insecure");
                   1063: 	$self->{TransactionRequest} = $self->{TransactionReply};
                   1064: 	$self->{InformWritable}     = 1;
                   1065: 	$self->{InformReadable}     = 0;
                   1066: 	$self->Transition("ChallengeReceived");
                   1067: 	$self->{TimeoutRemaining}   = $self->{TimeoutValue};
                   1068: 	return 0;
                   1069: 	
                   1070: 	
                   1071:     }
                   1072:     else {
                   1073: 	&Debug(3, "Insecure key negotiation disabled!");
                   1074: 	my $socket = $self->{Socket};
                   1075: 	$socket->close;
                   1076: 	return -1;
                   1077:     }
                   1078: }
1.1       foxr     1079: 
1.14      foxr     1080: ###########################################################
                   1081: #
                   1082: #  The following is an unashamed kludge that is here to
                   1083: # allow LondConnection to be used outside of the
                   1084: # loncapa environment (e.g. by lonManage).
                   1085: # 
                   1086: #   This is a textual inclusion of pieces of the
                   1087: #   Configuration.pm module.
                   1088: #
                   1089: 
                   1090: 
1.43      raeburn  1091: my @confdirs=('/etc/httpd/conf/','/etc/apache2/');
1.14      foxr     1092: 
                   1093: # ------------------- Subroutine read_conf: read LON-CAPA server configuration.
                   1094: # This subroutine reads PerlSetVar values out of specified web server
                   1095: # configuration files.
                   1096: sub read_conf
                   1097:   {
                   1098:     my (@conf_files)=@_;
1.43      raeburn  1099:     my (%perlvar,%configdirs);
                   1100:     foreach my $filename (@conf_files,'loncapa_apache.conf') {
                   1101:         my $configdir = '';
                   1102:         $configdirs{$filename} = [@confdirs];
                   1103:         while ($configdir eq '' && @{$configdirs{$filename}} > 0) {
                   1104:             my $testdir = shift(@{$configdirs{$filename}});
                   1105:             if (-e $testdir.$filename) {
                   1106:                 $configdir = $testdir;
                   1107:             }
                   1108:         }
                   1109:         if ($configdir eq '') {
                   1110:             die("Couldn't find a directory containing $filename");
                   1111:         }
                   1112: 	if($DebugLevel > 3) {
                   1113: 	    print STDERR ("Going to read $configdir.$filename\n");
                   1114: 	}
                   1115: 	open(CONFIG,'<'.$configdir.$filename) or
                   1116: 	    die("Can't read $configdir$filename");
                   1117: 	while (my $configline=<CONFIG>) {
                   1118: 	    if ($configline =~ /^[^\#]*PerlSetVar/) {
                   1119: 	        my ($unused,$varname,$varvalue)=split(/\s+/,$configline);
1.14      foxr     1120: 		chomp($varvalue);
                   1121: 		$perlvar{$varname}=$varvalue;
1.43      raeburn  1122: 	    }
                   1123: 	}
1.14      foxr     1124: 	close(CONFIG);
1.43      raeburn  1125:     }
1.21      foxr     1126:     if($DebugLevel > 3) {
1.31      foxr     1127: 	print STDERR "Dumping perlvar:\n";
1.21      foxr     1128: 	foreach my $var (keys %perlvar) {
1.31      foxr     1129: 	    print STDERR "$var = $perlvar{$var}\n";
1.21      foxr     1130: 	}
                   1131:     }
1.14      foxr     1132:     my $perlvarref=\%perlvar;
1.21      foxr     1133:     return $perlvarref;
                   1134: }
1.14      foxr     1135: 
1.24      foxr     1136: #
                   1137: #   Get the version of our peer.  Note that this is only well
                   1138: #   defined if the state machine has hit the idle state at least
                   1139: #   once (well actually if it has transitioned out of 
                   1140: #   ReadingVersionString   The member data LondVersion is returned.
                   1141: #
                   1142: sub PeerVersion {
                   1143:    my $self = shift;
1.40      albertel 1144:    my ($version) = ($self->{LondVersion} =~ /Revision: 1\.(\d+)/);
                   1145:    return $version;
1.24      foxr     1146: }
1.1       foxr     1147: 
1.52      foxr     1148: #
                   1149: #  Manipulate the client data field
                   1150: #
                   1151: sub SetClientData {
                   1152:     my ($self, $newData) = @_;
                   1153:     $self->{ClientData} = $newData;
                   1154: }
                   1155: #
                   1156: #  Get the current client data field.
                   1157: #
                   1158: sub GetClientData {
                   1159:     my $self = shift;
                   1160:     return $self->{ClientData};
                   1161: }
                   1162: 
1.53.2.1! raeburn  1163: #
        !          1164: # Get the HostID of our peer 
        !          1165: #
        !          1166: 
        !          1167: sub PeerLoncapaHim {
        !          1168:     my $self = shift;
        !          1169:     return $self->{LoncapaHim};
        !          1170: }
        !          1171: 
1.1       foxr     1172: 1;
                   1173: 
                   1174: =pod
1.3       albertel 1175: 
1.1       foxr     1176: =head1 Theory
                   1177: 
1.3       albertel 1178: The lond object is a state machine.  It lives through the following states:
                   1179: 
                   1180: =item Connected:
                   1181: 
                   1182: a TCP connection has been formed, but the passkey has not yet been
                   1183: negotiated.
                   1184: 
                   1185: =item Initialized:
                   1186: 
                   1187: "init" sent.
                   1188: 
                   1189: =item ChallengeReceived:
                   1190: 
                   1191: lond sent its challenge to us.
                   1192: 
                   1193: =item ChallengeReplied:
                   1194: 
                   1195: We replied to lond's challenge waiting for lond's ok.
                   1196: 
                   1197: =item RequestingKey:
                   1198: 
                   1199: We are requesting an encryption key.
                   1200: 
                   1201: =item ReceivingKey:
                   1202: 
                   1203: We are receiving an encryption key.
                   1204: 
                   1205: =item Idle:
                   1206: 
                   1207: Connection was negotiated but no requests are active.
                   1208: 
                   1209: =item SendingRequest:
                   1210: 
                   1211: A request is being sent to the peer.
                   1212: 
                   1213: =item ReceivingReply:
                   1214: 
                   1215: Waiting for an entire reply from the peer.
                   1216: 
                   1217: =item Disconnected:
                   1218: 
                   1219: For whatever reason, the connection was dropped.
                   1220: 
                   1221: When we need to be writing data, we have a writable event. When we
                   1222: need to be reading data, a readable event established.  Events
                   1223: dispatch through the class functions Readable and Writable, and the
                   1224: watcher contains a reference to the associated object to allow object
                   1225: context to be reached.
1.1       foxr     1226: 
                   1227: =head2 Member data.
                   1228: 
1.3       albertel 1229: =item Host
                   1230: 
                   1231: Host socket is connected to.
                   1232: 
                   1233: =item Port
                   1234: 
                   1235: The port the remote lond is listening on.
                   1236: 
                   1237: =item Socket
                   1238: 
                   1239: Socket open on the connection.
                   1240: 
                   1241: =item State
                   1242: 
                   1243: The current state.
                   1244: 
1.31      foxr     1245: =item AuthenticationMode
                   1246: 
                   1247: How authentication is being done. This can be any of:
                   1248: 
                   1249:     o local - Authenticate via a key exchanged in a file.
                   1250:     o ssl   - Authenticate via a key exchaned through a temporary ssl tunnel.
                   1251:     o insecure - Exchange keys in an insecure manner.
                   1252: 
                   1253: insecure is only allowed if the configuration parameter loncAllowInsecure 
                   1254: is nonzero.
                   1255: 
1.3       albertel 1256: =item TransactionRequest
                   1257: 
                   1258: The request being transmitted.
                   1259: 
                   1260: =item TransactionReply
                   1261: 
                   1262: The reply being received from the transaction.
                   1263: 
                   1264: =item InformReadable
                   1265: 
                   1266: True if we want to be called when socket is readable.
                   1267: 
                   1268: =item InformWritable
                   1269: 
                   1270: True if we want to be informed if the socket is writable.
                   1271: 
                   1272: =item Timeoutable
                   1273: 
                   1274: True if the current operation is allowed to timeout.
                   1275: 
                   1276: =item TimeoutValue
                   1277: 
                   1278: Number of seconds in the timeout.
                   1279: 
                   1280: =item TimeoutRemaining
                   1281: 
                   1282: Number of seconds left in the timeout.
                   1283: 
                   1284: =item CipherKey
                   1285: 
                   1286: The key that was negotiated with the peer.
                   1287: 
                   1288: =item Cipher
                   1289: 
                   1290: The cipher obtained via the key.
1.1       foxr     1291: 
                   1292: 
                   1293: =head2 The following are callback like members:
1.3       albertel 1294: 
                   1295: =item Tick:
                   1296: 
                   1297: Called in response to a timer tick. Used to managed timeouts etc.
                   1298: 
                   1299: =item Readable:
                   1300: 
                   1301: Called when the socket becomes readable.
                   1302: 
                   1303: =item Writable:
                   1304: 
                   1305: Called when the socket becomes writable.
                   1306: 
                   1307: =item TimedOut:
                   1308: 
                   1309: Called when a timed operation timed out.
                   1310: 
1.1       foxr     1311: 
                   1312: =head2 The following are operational member functions.
1.3       albertel 1313: 
                   1314: =item InitiateTransaction:
                   1315: 
                   1316: Called to initiate a new transaction
                   1317: 
                   1318: =item SetStateTransitionCallback:
                   1319: 
                   1320: Called to establish a function that is called whenever the object goes
                   1321: through a state transition.  This is used by The client to manage the
                   1322: work flow for the object.
                   1323: 
                   1324: =item SetTimeoutCallback:
                   1325: 
                   1326: Set a function to be called when a transaction times out.  The
                   1327: function will be called with the object as its sole parameter.
                   1328: 
                   1329: =item Encrypt:
                   1330: 
                   1331: Encrypts a block of text according to the cipher negotiated with the
                   1332: peer (assumes the text is a command).
                   1333: 
                   1334: =item Decrypt:
                   1335: 
                   1336: Decrypts a block of text according to the cipher negotiated with the
                   1337: peer (assumes the block was a reply.
1.5       foxr     1338: 
                   1339: =item Shutdown:
                   1340: 
                   1341: Shuts off the socket.
1.1       foxr     1342: 
                   1343: =head2 The following are selector member functions:
                   1344: 
1.3       albertel 1345: =item GetState:
                   1346: 
                   1347: Returns the current state
                   1348: 
                   1349: =item GetSocket:
                   1350: 
                   1351: Gets the socekt open on the connection to lond.
                   1352: 
                   1353: =item WantReadable:
                   1354: 
                   1355: true if the current state requires a readable event.
                   1356: 
                   1357: =item WantWritable:
                   1358: 
                   1359: true if the current state requires a writable event.
                   1360: 
                   1361: =item WantTimeout:
                   1362: 
                   1363: true if the current state requires timeout support.
                   1364: 
1.1       foxr     1365: =cut

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