# This module defines and implements a class that represents # a connection to a lond daemon. # # $Id: LondConnection.pm,v 1.35 2004/09/21 10:51:42 foxr Exp $ # # Copyright Michigan State University Board of Trustees # # This file is part of the LearningOnline Network with CAPA (LON-CAPA). # # LON-CAPA is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # LON-CAPA is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with LON-CAPA; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # # /home/httpd/html/adm/gpl.txt # # http://www.lon-capa.org/ # package LondConnection; use strict; use IO::Socket; use IO::Socket::INET; use IO::Handle; use IO::File; use Fcntl; use POSIX; use Crypt::IDEA; use LONCAPA::lonlocal; use LONCAPA::lonssl; my $DebugLevel=0; my %hostshash; my %perlvar; my $LocalDns = ""; # Need not be defined for managers. my $InsecureOk; # # Set debugging level # sub SetDebug { $DebugLevel = shift; } # # The config read is done in this way to support the read of # the non-default configuration file in the # event we are being used outside of loncapa. # my $ConfigRead = 0; # Read the configuration file for apache to get the perl # variables set. sub ReadConfig { Debug(8, "ReadConfig called"); my $perlvarref = read_conf('loncapa.conf'); %perlvar = %{$perlvarref}; my $hoststab = read_hosts( "$perlvar{lonTabDir}/hosts.tab") || die "Can't read host table!!"; %hostshash = %{$hoststab}; $ConfigRead = 1; my $myLonCapaName = $perlvar{lonHostID}; Debug(8, "My loncapa name is $myLonCapaName"); if(defined $hostshash{$myLonCapaName}) { Debug(8, "My loncapa name is in hosthash"); my @ConfigLine = @{$hostshash{$myLonCapaName}}; $LocalDns = $ConfigLine[3]; Debug(8, "Got local name $LocalDns"); } $InsecureOk = $perlvar{loncAllowInsecure}; Debug(3, "ReadConfig - LocalDNS = $LocalDns"); } # # Read a foreign configuration. # This sub is intended for the cases where the package # will be read from outside the LonCAPA environment, in that case # the client will need to explicitly provide: # - A file in hosts.tab format. # - Some idea of the 'lonCAPA' name of the local host (for building # the encryption key). # # Parameters: # MyHost - Name of this host as far as LonCAPA is concerned. # Filename - Name of a hosts.tab formatted file that will be used # to build up the hosts table. # sub ReadForeignConfig { my ($MyHost, $Filename) = @_; &Debug(4, "ReadForeignConfig $MyHost $Filename\n"); $perlvar{lonHostID} = $MyHost; # Rmember my host. my $hosttab = read_hosts($Filename) || die "Can't read hosts table!!"; %hostshash = %{$hosttab}; if($DebugLevel > 3) { foreach my $host (keys %hostshash) { print STDERR "host $host => $hostshash{$host}\n"; } } $ConfigRead = 1; my $myLonCapaName = $perlvar{lonHostID}; if(defined $hostshash{$myLonCapaName}) { my @ConfigLine = @{$hostshash{$myLonCapaName}}; $LocalDns = $ConfigLine[3]; } $InsecureOk = $perlvar{loncAllowInsecure}; Debug(3, "ReadForeignConfig - LocalDNS = $LocalDns"); } sub Debug { my ($level, $message) = @_; if ($level < $DebugLevel) { print STDERR ($message."\n"); } } =pod =head2 Dump Dump the internal state of the object: For debugging purposes, to stderr. =cut sub Dump { my $self = shift; my $level = shift; my $now = time; my $local = localtime($now); if ($level <= $DebugLevel) { return; } my $key; my $value; print STDERR "[ $local ] Dumping LondConnectionObject:\n"; while(($key, $value) = each %$self) { print STDERR "$key -> $value\n"; } print STDERR "-------------------------------\n"; } =pod Local function to do a state transition. If the state transition callback is defined it is called with two parameters: the self and the old state. =cut sub Transition { my ($self, $newstate) = @_; my $oldstate = $self->{State}; $self->{State} = $newstate; $self->{TimeoutRemaining} = $self->{TimeoutValue}; if($self->{TransitionCallback}) { ($self->{TransitionCallback})->($self, $oldstate); } } =pod =head2 new Construct a new lond connection. Parameters (besides the class name) include: =item hostname host the remote lond is on. This host is a host in the hosts.tab file =item port port number the remote lond is listening on. =cut sub new { my ($class, $Hostname, $Port) = @_; if (!$ConfigRead) { ReadConfig(); $ConfigRead = 1; } &Debug(4,$class."::new( ".$Hostname.",".$Port.")\n"); # The host must map to an entry in the hosts table: # We connect to the dns host that corresponds to that # system and use the hostname for the encryption key # negotion. In the objec these become the Host and # LoncapaHim fields of the object respectively. # if (!exists $hostshash{$Hostname}) { &Debug(8, "No Such host $Hostname"); return undef; # No such host!!! } my @ConfigLine = @{$hostshash{$Hostname}}; my $DnsName = $ConfigLine[3]; # 4'th item is dns of host. Debug(5, "Connecting to ".$DnsName); # Now create the object... my $self = { Host => $DnsName, LoncapaHim => $Hostname, Port => $Port, State => "Initialized", AuthenticationMode => "", TransactionRequest => "", TransactionReply => "", InformReadable => 0, InformWritable => 0, TimeoutCallback => undef, TransitionCallback => undef, Timeoutable => 0, TimeoutValue => 30, TimeoutRemaining => 0, LocalKeyFile => "", CipherKey => "", LondVersion => "Unknown", Cipher => undef}; bless($self, $class); unless ($self->{Socket} = IO::Socket::INET->new(PeerHost => $self->{Host}, PeerPort => $self->{Port}, Type => SOCK_STREAM, Proto => "tcp", Timeout => 3)) { return undef; # Inidicates the socket could not be made. } my $socket = $self->{Socket}; # For local use only. # If we are local, we'll first try local auth mode, otherwise, we'll try # the ssl auth mode: Debug(8, "Connecting to $DnsName I am $LocalDns"); my $key; my $keyfile; if ($DnsName eq $LocalDns) { $self->{AuthenticationMode} = "local"; ($key, $keyfile) = lonlocal::CreateKeyFile(); Debug(8, "Local key: $key, stored in $keyfile"); # If I can't make the key file fall back to insecure if # allowed...else give up right away. if(!(defined $key) || !(defined $keyfile)) { if($InsecureOk) { $self->{AuthenticationMode} = "insecure"; $self->{TransactionRequest} = "init\n"; } else { $socket->close; return undef; } } $self->{TransactionRequest} = "init:local:$keyfile\n"; Debug(9, "Init string is init:local:$keyfile"); if(!$self->CreateCipher($key)) { # Nothing's going our way... $socket->close; return undef; } } else { # Remote peer: I'd like to do ssl, but if my host key or certificates # are not all installed, my only choice is insecure, if that's # allowed: my ($ca, $cert) = lonssl::CertificateFile; my $sslkeyfile = lonssl::KeyFile; if((defined $ca) && (defined $cert) && (defined $sslkeyfile)) { $self->{AuthenticationMode} = "ssl"; $self->{TransactionRequest} = "init:ssl\n"; } else { if($InsecureOk) { # Allowed to do insecure: $self->{AuthenticationMode} = "insecure"; $self->{TransactionRequest} = "init\n"; } else { # Not allowed to do insecure... $socket->close; return undef; } } } # # We're connected. Set the state, and the events we'll accept: # $self->Transition("Connected"); $self->{InformWritable} = 1; # When socket is writable we send init $self->{Timeoutable} = 1; # Timeout allowed during startup negotiation. # # Set socket to nonblocking I/O. # my $socket = $self->{Socket}; my $flags = fcntl($socket, F_GETFL,0); if(!$flags) { $socket->close; return undef; } if(!fcntl($socket, F_SETFL, $flags | O_NONBLOCK)) { $socket->close; return undef; } # return the object : Debug(9, "Initial object state: "); $self->Dump(9); return $self; } =pod =head2 Readable This member should be called when the Socket becomes readable. Until the read completes, action is state independet. Data are accepted into the TransactionReply until a newline character is received. At that time actionis state dependent: =item Connected in this case we received challenge, the state changes to ChallengeReceived, and we initiate a send with the challenge response. =item ReceivingReply In this case a reply has been received for a transaction, the state goes to Idle and we disable write and read notification. =item ChallengeReeived we just got what should be an ok\n and the connection can now handle transactions. =cut sub Readable { my $self = shift; my $socket = $self->{Socket}; my $data = ''; my $rv; my $ConnectionMode = $self->{AuthenticationMode}; if ($socket) { eval { $rv = $socket->recv($data, POSIX::BUFSIZ, 0); } } else { $self->Transition("Disconnected"); return -1; } my $errno = $! + 0; # Force numeric context. unless (defined($rv) && length $data) {# Read failed, if(($errno == POSIX::EWOULDBLOCK) || ($errno == POSIX::EAGAIN) || ($errno == POSIX::EINTR)) { return 0; } # Connection likely lost. &Debug(4, "Connection lost"); $self->{TransactionRequest} = ''; $socket->close(); $self->Transition("Disconnected"); return -1; } # Append the data to the buffer. And figure out if the read is done: &Debug(9,"Received from host: ".$data); $self->{TransactionReply} .= $data; if($self->{TransactionReply} =~ m/\n$/) { &Debug(8,"Readable End of line detected"); if ($self->{State} eq "Initialized") { # We received the challenge: # Our init was replied to. What happens next depends both on # the actual init we sent (AuthenticationMode member data) # and the response: # AuthenticationMode == local: # Response ok: The key has been exchanged and # the key file destroyed. We can jump # into setting the host and requesting the # Later we'll also bypass key exchange. # Response digits: # Old style lond. Delete the keyfile. # If allowed fall back to insecure mode. # else close connection and fail. # Response other: # Failed local auth # Close connection and fail. # # AuthenticationMode == ssl: # Response ok:ssl # Response digits: # Response other: # Authentication mode == insecure # Response digits # Response other: my $Response = $self->{TransactionReply}; if($ConnectionMode eq "local") { if($Response =~ /^ok:local/) { # Good local auth. $self->ToVersionRequest(); return 0; } elsif ($Response =~/^[0-9]+/) { # Old style lond. return $self->CompleteInsecure(); } else { # Complete flop &Debug(3, "init:local : unrecognized reply"); $self->Transition("Disconnected"); $socket->close; return -1; } } elsif ($ConnectionMode eq "ssl") { if($Response =~ /^ok:ssl/) { # Good ssl... if($self->ExchangeKeysViaSSL()) { # Success skip to vsn stuff # Need to reset to non blocking: my $flags = fcntl($socket, F_GETFL, 0); fcntl($socket, F_SETFL, $flags | O_NONBLOCK); $self->ToVersionRequest(); return 0; } else { # Failed in ssl exchange. &Debug(3,"init:ssl failed key negotiation!"); $self->Transition("Disconnected"); $socket->close; return -1; } } elsif ($Response =~ /^[0-9]+/) { # Old style lond. return $self->CompleteInsecure(); } else { # Complete flop } } elsif ($ConnectionMode eq "insecure") { if($self->{TransactionReply} eq "refused\n") { # Remote doesn't have $self->Transition("Disconnected"); # in host tables. $socket->close(); return -1; } return $self->CompleteInsecure(); } else { &Debug(1,"Authentication mode incorrect"); die "BUG!!! LondConnection::Readable invalid authmode"; } } elsif ($self->{State} eq "ChallengeReplied") { if($self->{TransactionReply} ne "ok\n") { $self->Transition("Disconnected"); $socket->close(); return -1; } $self->ToVersionRequest(); return 0; } elsif ($self->{State} eq "ReadingVersionString") { $self->{LondVersion} = chomp($self->{TransactionReply}); $self->Transition("SetHost"); $self->{InformReadable} = 0; $self->{InformWritable} = 1; my $peer = $self->{LoncapaHim}; $self->{TransactionRequest}= "sethost:$peer\n"; return 0; } elsif ($self->{State} eq "HostSet") { # should be ok. if($self->{TransactionReply} ne "ok\n") { $self->Transition("Disconnected"); $socket->close(); return -1; } # If the auth mode is insecure we must still # exchange session keys. Otherwise, # we can just transition to idle. if($ConnectionMode eq "insecure") { $self->Transition("RequestingKey"); $self->{InformReadable} = 0; $self->{InformWritable} = 1; $self->{TransactionRequest} = "ekey\n"; return 0; } else { $self->ToIdle(); return 0; } } elsif ($self->{State} eq "ReceivingKey") { my $buildkey = $self->{TransactionReply}; my $key = $self->{LoncapaHim}.$perlvar{'lonHostID'}; $key=~tr/a-z/A-Z/; $key=~tr/G-P/0-9/; $key=~tr/Q-Z/0-9/; $key =$key.$buildkey.$key.$buildkey.$key.$buildkey; $key = substr($key,0,32); if(!$self->CreateCipher($key)) { $self->Transition("Disconnected"); $socket->close(); return -1; } else { $self->ToIdle(); return 0; } } elsif ($self->{State} eq "ReceivingReply") { # If the data are encrypted, decrypt first. my $answer = $self->{TransactionReply}; if($answer =~ /^enc\:/) { $answer = $self->Decrypt($answer); $self->{TransactionReply} = "$answer\n"; } # finish the transaction $self->ToIdle(); return 0; } elsif ($self->{State} eq "Disconnected") { # No connection. return -1; } else { # Internal error: Invalid state. $self->Transition("Disconnected"); $socket->close(); return -1; } } return 0; } =pod This member should be called when the Socket becomes writable. The action is state independent. An attempt is made to drain the contents of the TransactionRequest member. Once this is drained, we mark the object as waiting for readability. Returns 0 if successful, or -1 if not. =cut sub Writable { my $self = shift; # Get reference to the object. my $socket = $self->{Socket}; my $nwritten; if ($socket) { eval { $nwritten = $socket->send($self->{TransactionRequest}, 0); } } else { # For whatever reason, there's no longer a socket left. $self->Transition("Disconnected"); return -1; } my $errno = $! + 0; unless (defined $nwritten) { if($errno != POSIX::EINTR) { $self->Transition("Disconnected"); return -1; } } if (($nwritten >= 0) || ($errno == POSIX::EWOULDBLOCK) || ($errno == POSIX::EAGAIN) || ($errno == POSIX::EINTR) || ($errno == 0)) { substr($self->{TransactionRequest}, 0, $nwritten) = ""; # rmv written part if(length $self->{TransactionRequest} == 0) { $self->{InformWritable} = 0; $self->{InformReadable} = 1; $self->{TransactionReply} = ''; # # Figure out the next state: # if($self->{State} eq "Connected") { $self->Transition("Initialized"); } elsif($self->{State} eq "ChallengeReceived") { $self->Transition("ChallengeReplied"); } elsif($self->{State} eq "RequestingVersion") { $self->Transition("ReadingVersionString"); } elsif ($self->{State} eq "SetHost") { $self->Transition("HostSet"); } elsif($self->{State} eq "RequestingKey") { $self->Transition("ReceivingKey"); # $self->{InformWritable} = 0; # $self->{InformReadable} = 1; # $self->{TransactionReply} = ''; } elsif ($self->{State} eq "SendingRequest") { $self->Transition("ReceivingReply"); $self->{TimeoutRemaining} = $self->{TimeoutValue}; } elsif ($self->{State} eq "Disconnected") { return -1; } return 0; } } else { # The write failed (e.g. partner disconnected). $self->Transition("Disconnected"); $socket->close(); return -1; } } =pod =head2 Tick Tick is called every time unit by the event framework. It =item 1 decrements the remaining timeout. =item 2 If the timeout is zero, calls TimedOut indicating that the current operation timed out. =cut sub Tick { my $self = shift; $self->{TimeoutRemaining}--; if ($self->{TimeoutRemaining} < 0) { $self->TimedOut(); } } =pod =head2 TimedOut called on a timeout. If the timeout callback is defined, it is called with $self as its parameters. =cut sub TimedOut { my $self = shift; if($self->{TimeoutCallback}) { my $callback = $self->{TimeoutCallback}; my @args = ( $self); &$callback(@args); } } =pod =head2 InitiateTransaction Called to initiate a transaction. A transaction can only be initiated when the object is idle... otherwise an error is returned. A transaction consists of a request to the server that will have a reply. This member sets the request data in the TransactionRequest member, makes the state SendingRequest and sets the data to allow a timout, and to request writability notification. =cut sub InitiateTransaction { my ($self, $data) = @_; Debug(1, "initiating transaction: ".$data); if($self->{State} ne "Idle") { Debug(0," .. but not idle here\n"); return -1; # Error indicator. } # if the transaction is to be encrypted encrypt the data: if($data =~ /^encrypt\:/) { $data = $self->Encrypt($data); } # Setup the trasaction $self->{TransactionRequest} = $data; $self->{TransactionReply} = ""; $self->{InformWritable} = 1; $self->{InformReadable} = 0; $self->{Timeoutable} = 1; $self->{TimeoutRemaining} = $self->{TimeoutValue}; $self->Transition("SendingRequest"); } =pod =head2 SetStateTransitionCallback Sets a callback for state transitions. Returns a reference to any prior established callback, or undef if there was none: =cut sub SetStateTransitionCallback { my $self = shift; my $oldCallback = $self->{TransitionCallback}; $self->{TransitionCallback} = shift; return $oldCallback; } =pod =head2 SetTimeoutCallback Sets the timeout callback. Returns a reference to any prior established callback or undef if there was none. =cut sub SetTimeoutCallback { my ($self, $callback) = @_; my $oldCallback = $self->{TimeoutCallback}; $self->{TimeoutCallback} = $callback; return $oldCallback; } =pod =head2 Shutdown: Shuts down the socket. =cut sub Shutdown { my $self = shift; my $socket = $self->GetSocket(); Debug(5,"socket is -$socket-"); if ($socket) { # Ask lond to exit too. Non blocking so # there is no cost for failure. eval { $socket->send("exit\n", 0); $socket->shutdown(2); } } } =pod =head2 GetState selector for the object state. =cut sub GetState { my $self = shift; return $self->{State}; } =pod =head2 GetSocket selector for the object socket. =cut sub GetSocket { my $self = shift; return $self->{Socket}; } =pod =head2 WantReadable Return the state of the flag that indicates the object wants to be called when readable. =cut sub WantReadable { my $self = shift; return $self->{InformReadable}; } =pod =head2 WantWritable Return the state of the flag that indicates the object wants write notification. =cut sub WantWritable { my $self = shift; return $self->{InformWritable}; } =pod =head2 WantTimeout return the state of the flag that indicates the object wants to be informed of timeouts. =cut sub WantTimeout { my $self = shift; return $self->{Timeoutable}; } =pod =head2 GetReply Returns the reply from the last transaction. =cut sub GetReply { my $self = shift; return $self->{TransactionReply}; } =pod =head2 Encrypt Returns the encrypted version of the command string. The command input string is of the form: encrypt:command The output string can be directly sent to lond as it is of the form: enc:length: =cut sub Encrypt { my ($self, $request) = @_; # Split the encrypt: off the request and figure out it's length. # the cipher works in blocks of 8 bytes. my $cmd = $request; $cmd =~ s/^encrypt\://; # strip off encrypt: chomp($cmd); # strip off trailing \n my $length=length($cmd); # Get the string length. $cmd .= " "; # Pad with blanks so we can fill out a block. # encrypt the request in 8 byte chunks to create the encrypted # output request. my $Encoded = ''; for(my $index = 0; $index <= $length; $index += 8) { $Encoded .= unpack("H16", $self->{Cipher}->encrypt(substr($cmd, $index, 8))); } # Build up the answer as enc:length:$encrequest. $request = "enc:$length:$Encoded\n"; return $request; } =pod =head2 Decrypt Decrypt a response from the server. The response is in the form: enc:: =cut sub Decrypt { my ($self, $encrypted) = @_; # Bust up the response into length, and encryptedstring: my ($enc, $length, $EncryptedString) = split(/:/,$encrypted); chomp($EncryptedString); # Decode the data in 8 byte blocks. The string is encoded # as hex digits so there are two characters per byte: my $decrypted = ""; for(my $index = 0; $index < length($EncryptedString); $index += 16) { $decrypted .= $self->{Cipher}->decrypt( pack("H16", substr($EncryptedString, $index, 16))); } # the answer may have trailing pads to fill out a block. # $length tells us the actual length of the decrypted string: $decrypted = substr($decrypted, 0, $length); Debug(9, "Decrypted $EncryptedString to $decrypted"); return $decrypted; } # ToIdle # Called to transition to idle... done enough it's worth subbing # off to ensure it's always done right!! # sub ToIdle { my $self = shift; $self->Transition("Idle"); $self->{InformWritiable} = 0; $self->{InformReadable} = 0; $self->{Timeoutable} = 0; } # ToVersionRequest # Called to transition to "RequestVersion" also done a few times # so worth subbing out. # sub ToVersionRequest { my $self = shift; $self->Transition("RequestingVersion"); $self->{InformReadable} = 0; $self->{InformWritable} = 1; $self->{TransactionRequest} = "version\n"; } # # CreateCipher # Given a cipher key stores the key in the object context, # creates the cipher object, (stores that in object context), # This is done a couple of places, so it's worth factoring it out. # # Parameters: # (self) # key - The Cipher key. # # Returns: # 0 - Failure to create IDEA cipher. # 1 - Success. # sub CreateCipher { my ($self, $key) = @_; # According to coding std. $self->{CipherKey} = $key; # Save the text key... my $packedkey = pack ("H32", $key); my $cipher = new IDEA $packedkey; if($cipher) { $self->{Cipher} = $cipher; Debug("Cipher created dumping socket: "); $self->Dump(9); return 1; } else { return 0; } } # ExchangeKeysViaSSL # Called to do cipher key exchange via SSL. # The socket is promoted to an SSL socket. If that's successful, # we read out cipher key through the socket and create an IDEA # cipher object. # Parameters: # (self) # Returns: # true - Success. # false - Failure. # # Assumptions: # 1. The ssl session setup has timeout logic built in so we don't # have to worry about DOS attacks at that stage. # 2. If the ssl session gets set up we are talking to a legitimate # lond so again we don't have to worry about DOS attacks. # All this allows us just to call sub ExchangeKeysViaSSL { my $self = shift; my $socket = $self->{Socket}; # Get our signed certificate, the certificate authority's # certificate and our private key file. All of these # are needed to create the ssl connection. my ($SSLCACertificate, $SSLCertificate) = lonssl::CertificateFile(); my $SSLKey = lonssl::KeyFile(); # Promote our connection to ssl and read the key from lond. my $SSLSocket = lonssl::PromoteClientSocket($socket, $SSLCACertificate, $SSLCertificate, $SSLKey); if(defined $SSLSocket) { my $key = <$SSLSocket>; lonssl::Close($SSLSocket); if($key) { chomp($key); # \n is not part of the key. return $self->CreateCipher($key); } else { Debug(3, "Failed to read ssl key"); return 0; } } else { # Failed!! Debug(3, "Failed to negotiate SSL connection!"); return 0; } # should not get here return 0; } # # CompleteInsecure: # This function is called to initiate the completion of # insecure challenge response negotiation. # To do this, we copy the challenge string to the transaction # request, flip to writability and state transition to # ChallengeReceived.. # All this is only possible if InsecureOk is true. # Parameters: # (self) - This object's context hash. # Return: # 0 - Ok to transition. # -1 - Not ok to transition (InsecureOk not ok). # sub CompleteInsecure { my $self = shift; if($InsecureOk) { $self->{AuthenticationMode} = "insecure"; &Debug(8," Transition out of Initialized:insecure"); $self->{TransactionRequest} = $self->{TransactionReply}; $self->{InformWritable} = 1; $self->{InformReadable} = 0; $self->Transition("ChallengeReceived"); $self->{TimeoutRemaining} = $self->{TimeoutValue}; return 0; } else { &Debug(3, "Insecure key negotiation disabled!"); my $socket = $self->{Socket}; $socket->close; return -1; } } =pod =head2 GetHostIterator Returns a hash iterator to the host information. Each get from this iterator returns a reference to an array that contains information read from the hosts configuration file. Array elements are used as follows: [0] - LonCapa host name. [1] - LonCapa domain name. [2] - Loncapa role (e.g. library or access). [3] - DNS name server hostname. [4] - IP address (result of e.g. nslookup [3]). [5] - Maximum connection count. [6] - Idle timeout for reducing connection count. [7] - Minimum connection count. =cut sub GetHostIterator { return HashIterator->new(\%hostshash); } ########################################################### # # The following is an unashamed kludge that is here to # allow LondConnection to be used outside of the # loncapa environment (e.g. by lonManage). # # This is a textual inclusion of pieces of the # Configuration.pm module. # my $confdir='/etc/httpd/conf/'; # ------------------- Subroutine read_conf: read LON-CAPA server configuration. # This subroutine reads PerlSetVar values out of specified web server # configuration files. sub read_conf { my (@conf_files)=@_; my %perlvar; foreach my $filename (@conf_files,'loncapa_apache.conf') { if($DebugLevel > 3) { print STDERR ("Going to read $confdir.$filename\n"); } open(CONFIG,'<'.$confdir.$filename) or die("Can't read $confdir$filename"); while (my $configline=) { if ($configline =~ /^[^\#]*PerlSetVar/) { my ($unused,$varname,$varvalue)=split(/\s+/,$configline); chomp($varvalue); $perlvar{$varname}=$varvalue; } } close(CONFIG); } if($DebugLevel > 3) { print STDERR "Dumping perlvar:\n"; foreach my $var (keys %perlvar) { print STDERR "$var = $perlvar{$var}\n"; } } my $perlvarref=\%perlvar; return $perlvarref; } #---------------------- Subroutine read_hosts: Read a LON-CAPA hosts.tab # formatted configuration file. # my $RequiredCount = 5; # Required item count in hosts.tab. my $DefaultMaxCon = 5; # Default value for maximum connections. my $DefaultIdle = 1000; # Default connection idle time in seconds. my $DefaultMinCon = 0; # Default value for minimum connections. sub read_hosts { my $Filename = shift; my %HostsTab; open(CONFIG,'<'.$Filename) or die("Can't read $Filename"); while (my $line = ) { if (!($line =~ /^\s*\#/)) { my @items = split(/:/, $line); if(scalar @items >= $RequiredCount) { if (scalar @items == $RequiredCount) { # Only required items: $items[$RequiredCount] = $DefaultMaxCon; } if(scalar @items == $RequiredCount + 1) { # up through maxcon. $items[$RequiredCount+1] = $DefaultIdle; } if(scalar @items == $RequiredCount + 2) { # up through idle. $items[$RequiredCount+2] = $DefaultMinCon; } { my @list = @items; # probably not needed but I'm unsure of # about the scope of item so... $HostsTab{$list[0]} = \@list; } } } } close(CONFIG); my $hostref = \%HostsTab; return ($hostref); } # # Get the version of our peer. Note that this is only well # defined if the state machine has hit the idle state at least # once (well actually if it has transitioned out of # ReadingVersionString The member data LondVersion is returned. # sub PeerVersion { my $self = shift; return $self->{LondVersion}; } 1; =pod =head1 Theory The lond object is a state machine. It lives through the following states: =item Connected: a TCP connection has been formed, but the passkey has not yet been negotiated. =item Initialized: "init" sent. =item ChallengeReceived: lond sent its challenge to us. =item ChallengeReplied: We replied to lond's challenge waiting for lond's ok. =item RequestingKey: We are requesting an encryption key. =item ReceivingKey: We are receiving an encryption key. =item Idle: Connection was negotiated but no requests are active. =item SendingRequest: A request is being sent to the peer. =item ReceivingReply: Waiting for an entire reply from the peer. =item Disconnected: For whatever reason, the connection was dropped. When we need to be writing data, we have a writable event. When we need to be reading data, a readable event established. Events dispatch through the class functions Readable and Writable, and the watcher contains a reference to the associated object to allow object context to be reached. =head2 Member data. =item Host Host socket is connected to. =item Port The port the remote lond is listening on. =item Socket Socket open on the connection. =item State The current state. =item AuthenticationMode How authentication is being done. This can be any of: o local - Authenticate via a key exchanged in a file. o ssl - Authenticate via a key exchaned through a temporary ssl tunnel. o insecure - Exchange keys in an insecure manner. insecure is only allowed if the configuration parameter loncAllowInsecure is nonzero. =item TransactionRequest The request being transmitted. =item TransactionReply The reply being received from the transaction. =item InformReadable True if we want to be called when socket is readable. =item InformWritable True if we want to be informed if the socket is writable. =item Timeoutable True if the current operation is allowed to timeout. =item TimeoutValue Number of seconds in the timeout. =item TimeoutRemaining Number of seconds left in the timeout. =item CipherKey The key that was negotiated with the peer. =item Cipher The cipher obtained via the key. =head2 The following are callback like members: =item Tick: Called in response to a timer tick. Used to managed timeouts etc. =item Readable: Called when the socket becomes readable. =item Writable: Called when the socket becomes writable. =item TimedOut: Called when a timed operation timed out. =head2 The following are operational member functions. =item InitiateTransaction: Called to initiate a new transaction =item SetStateTransitionCallback: Called to establish a function that is called whenever the object goes through a state transition. This is used by The client to manage the work flow for the object. =item SetTimeoutCallback: Set a function to be called when a transaction times out. The function will be called with the object as its sole parameter. =item Encrypt: Encrypts a block of text according to the cipher negotiated with the peer (assumes the text is a command). =item Decrypt: Decrypts a block of text according to the cipher negotiated with the peer (assumes the block was a reply. =item Shutdown: Shuts off the socket. =head2 The following are selector member functions: =item GetState: Returns the current state =item GetSocket: Gets the socekt open on the connection to lond. =item WantReadable: true if the current state requires a readable event. =item WantWritable: true if the current state requires a writable event. =item WantTimeout: true if the current state requires timeout support. =item GetHostIterator: Returns an iterator into the host file hash. =cut