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/*
* Copyright (C) 2007-2023 Xagasoft, All rights reserved.
*
* This file is part of the libbu++ library and is released under the
* terms of the license contained in the file LICENSE.
*/
#ifndef BU_PROTOCOL_TELNET_H
#define BU_PROTOCOL_TELNET_H
#include "bu/protocol.h"
#include "bu/hash.h"
#include "bu/string.h"
#include "bu/mutex.h"
// #define __TELNET_DEBUG
namespace Bu
{
/**
* Telnet Protocol handler. This attempts to provide useful and general
* support for most of the most commonly used Telnet extensions in a simple
* and easy to use way. The Option variables control the settings that can
* be used on the line, and control which virtual "callbacks" will be called
* when different events happen.
*
* To setup initial values and to disable any options you wish override the
* onNewConnection function in your own class, like this:
*@code
class MyTelnet : public Bu::ProtocolTelnet
{
public:
...
virtual void onNewConnection( class Bu::Client *pClient )
{
// Call the parent class' onNewConnection to get everything all
// set up.
Bu::ProtocolTelnet::onNewConnection( pClient );
// These functions disable the option to send files via telnet,
// disabling the remote option means that we won't accept this
// option (binary data being sent to us) from the client.
//
// Disabling the local option means that the client cannot ask us
// to send them binary data.
oBinary.enableRemote( false );
oBinary.enableLocal( false );
// This requests that the client send us window size updates
// whenever the size of their window changes, and an initial set to
// boot.
//
// To see if this option is set later, try oNAWS.isRemoteSet(), but
// wait a little while, asking immediatly will always return false,
// since the remote side has yet to receive our request.
oNAWS.remoteSet();
}
}
@endcode
*
*@ingroup Serving
*/
class ProtocolTelnet : public Protocol
{
public:
ProtocolTelnet();
virtual ~ProtocolTelnet();
/**
* If you override this function in a child class, make sure to call
* this version of it as the very first thing that you do, before you
* set any options. See the example in the class docs.
*/
virtual void onNewConnection( class Bu::Client *pClient );
/**
* You should never override this function unless you really, really
* know what you're doing. If you want to get data after each line
* entered (in canonical mode) or after any data arrives (non canonical
* mode) then override the gotLine and gotData functions, respectively.
*/
virtual void onNewData( class Bu::Client *pClient );
/**
* Override this function to be notified of lines being submitted by
* the client. This function is only called in canonical mode, after
* all edits are performed on the data. In this mode weather you use
* the line or not, the data will be cleared from the buffer when this
* function returns, any changes made to the buffer will be destroyed.
*/
virtual void gotLine( Bu::String & /*sLine*/ ){};
/**
* Override this function to be notified of any new data that comes in
* from the client. This function is only called in non-canonical mode,
* and includes all raw data minus telnet control codes and ansi
* escape sequences. In this mode control of the buffer is up to the
* child class in this function, the buffer will never be cleared unless
* it happens in this function's override.
*/
virtual void gotData( Bu::String & /*sData*/ ){};
/**
* Using this function to enable or disable canonical mode only affects
* the way the data is processed and which virtual functions are called
* during processing. It does not affect options set locally or
* remotely. Setting this to false will enable char-at-a-time mode,
* effectively disabling internal line-editing code. Characters
* such as backspace that are detected will not be handled and will be
* sent to the user override. The subclass will also be notified every
* time new data is available, not just whole lines.
*
* When set to true (the default), line editing control codes will be
* interpreted and used, and the subclass will only be notified when
* complete lines are available in the buffer.
*/
void setCanonical( bool bCon=true );
bool isCanonical();
void setEcho( bool bOpt=true );
bool isEchoEnabled();
void write( const Bu::String &sData );
void write( const char *pData, int iSize );
void write( char cData );
void flush();
void close();
const Bu::String &getBuffer() { return sDataBuf; }
void setBuffer( const Bu::String &sNewBuffer );
void appendBuffer( const Bu::String &sNewData );
public:
/**
* If you wish to know the current dimensions of the client window,
* override this function, it will be called whenever the size changes.
*/
virtual void onSubNAWS( uint16_t /*iWidth*/, uint16_t /*iHeight*/ ){};
/**
* This function is called whenever an unknown sub negotiation option is
* sent over the line. This doesn't mean that it's malformatted, it
* just means that this class doesn't support that option yet, but you
* can handle it yourself if you'd like. Feel free to change the
* sSubBuf, it will be cleared as soon as this function returns anyway.
*/
virtual void onSubUnknown( char /*cSubOpt*/,
Bu::String & /*sSubBuf*/ ){};
private:
/**
* Represents a basic telnet option, either on or off, no parameters.
* Each Option can negotiate effectively on it's own, and has two
* parameters in each of two classes. Both local and remote can be
* enabled/disabled and set/unset. Enabled represents the ability to
* set the option, disabling an option should also unset it. Set or
* unset represent wether the option is being used, if it is allowed.
*/
class Option
{
friend class Bu::ProtocolTelnet;
private:
Option( ProtocolTelnet &rPT, char cCode );
virtual ~Option();
public:
void localEnable( bool bSet=true );
void localSet( bool bSet=true );
bool isLocalEnabled();
bool isLocalSet();
void remoteEnable( bool bSet=true );
void remoteSet( bool bSet=true );
bool isRemoteEnabled();
bool isRemoteSet();
private:
enum
{
fLocalCant = 0x01, /**< Local can't/won't allow option. */
fLocalIs = 0x02, /**< Local is using option. */
fRemoteCant = 0x04, /**< Remote can't/won't allow option. */
fRemoteIs = 0x08 /**< Remote is using option. */
};
ProtocolTelnet &rPT;
char fOpts;
char cCode;
};
friend class Bu::ProtocolTelnet::Option;
Hash<char, Option *> hOpts;
public:
Option oBinary;
Option oEcho;
Option oNAWS;
Option oSuppressGA;
private:
void onWill( char cCode );
void onWont( char cCode );
void onDo( char cCode );
void onDont( char cCode );
void onSubOpt();
void onCtlChar( char cChr );
#ifdef __TELNET_DEBUG
void printCode( char cCode );
void printOpt( char cOpt );
#endif
private:
Mutex mRead;
Mutex mWrite;
Client *pClient;
Bu::String sDataBuf; /**< Buffer for regular line data. */
Bu::String sSubBuf; /**< Buffer for subnegotiation data. */
char cSubOpt; /**< Which suboption are we processing. */
bool bCanonical; /**< Are we canonicalizing incoming data? */
bool bEcho; /**< Should chars be echoed? */
bool bSubOpt; /**< Are we processing a suboption right now? */
};
}
#endif
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