channels.h - security/openssh-library - Rivoreo Source Code Repositories

 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  *
  * As far as I am concerned, the code I have written for this software
  * can be used freely for any purpose.  Any derived versions of this
  * software must be clearly marked as such, and if the derived work is
  * incompatible with the protocol description in the RFC file, it must be
  * called by a name other than "ssh" or "Secure Shell".
  */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /* RCSID("$OpenBSD: channels.h,v 1.31 2001/04/13 22:46:53 beck Exp $"); */

 #ifndef CHANNELS_H
 #define CHANNELS_H

 #include "buffer.h"

 /* Definitions for channel types. */
 #define SSH_CHANNEL_FREE		0	/* This channel is free (unused). */
 #define SSH_CHANNEL_X11_LISTENER	1	/* Listening for inet X11 conn. */
 #define SSH_CHANNEL_PORT_LISTENER	2	/* Listening on a port. */
 #define SSH_CHANNEL_OPENING		3	/* waiting for confirmation */
 #define SSH_CHANNEL_OPEN		4	/* normal open two-way channel */
 #define SSH_CHANNEL_CLOSED		5	/* waiting for close confirmation */
 #define SSH_CHANNEL_AUTH_SOCKET		6	/* authentication socket */
 #define SSH_CHANNEL_X11_OPEN		7	/* reading first X11 packet */
 #define SSH_CHANNEL_INPUT_DRAINING	8	/* sending remaining data to conn */
 #define SSH_CHANNEL_OUTPUT_DRAINING	9	/* sending remaining data to app */
 #define SSH_CHANNEL_LARVAL		10	/* larval session */
 #define SSH_CHANNEL_RPORT_LISTENER	11	/* Listening to a R-style port  */
 #define SSH_CHANNEL_CONNECTING		12
 #define SSH_CHANNEL_DYNAMIC		13
 #define SSH_CHANNEL_MAX_TYPE		14

 /*
  * Data structure for channel data.  This is iniailized in channel_allocate
  * and cleared in channel_free.
  */
 struct Channel;
 typedef struct Channel Channel;

 typedef void channel_callback_fn(int id, void *arg);
 typedef int channel_filter_fn(struct Channel *c, char *buf, int len);

 struct Channel {
 	int     type;		/* channel type/state */
 	int     self;		/* my own channel identifier */
 	int     remote_id;	/* channel identifier for remote peer */
 	/* peer can be reached over encrypted connection, via packet-sent */
 	int     istate;		/* input from channel (state of receive half) */
 	int     ostate;		/* output to channel  (state of transmit half) */
 	int     flags;		/* close sent/rcvd */
 	int     rfd;		/* read fd */
 	int     wfd;		/* write fd */
 	int     efd;		/* extended fd */
 	int     sock;		/* sock fd */
 	int     isatty;		/* rfd is a tty */
 	Buffer  input;		/* data read from socket, to be sent over
 				 * encrypted connection */
 	Buffer  output;		/* data received over encrypted connection for
 				 * send on socket */
 	Buffer  extended;
 	char    path[200];	/* path for unix domain sockets, or host name
 				 * for forwards */
 	int     listening_port;	/* port being listened for forwards */
 	int     host_port;	/* remote port to connect for forwards */
 	char   *remote_name;	/* remote hostname */

 	int	remote_window;
 	int	remote_maxpacket;
 	int	local_window;
 	int	local_window_max;
 	int	local_consumed;
 	int	local_maxpacket;
 	int     extended_usage;

 	char   *ctype;		/* type */

 	/* callback */
 	channel_callback_fn	*cb_fn;
 	void	*cb_arg;
 	int	cb_event;
 	channel_callback_fn	*dettach_user;

 	/* filter */
 	channel_filter_fn	*input_filter;
 };

 #define CHAN_EXTENDED_IGNORE		0
 #define CHAN_EXTENDED_READ		1
 #define CHAN_EXTENDED_WRITE		2

 /* default window/packet sizes for tcp/x11-fwd-channel */
 #define CHAN_SES_WINDOW_DEFAULT	(32*1024)
 #define CHAN_SES_PACKET_DEFAULT	(CHAN_SES_WINDOW_DEFAULT/2)
 #define CHAN_TCP_WINDOW_DEFAULT	(32*1024)
 #define CHAN_TCP_PACKET_DEFAULT	(CHAN_TCP_WINDOW_DEFAULT/2)
 #define CHAN_X11_WINDOW_DEFAULT	(4*1024)
 #define CHAN_X11_PACKET_DEFAULT	(CHAN_X11_WINDOW_DEFAULT/2)


 void	channel_open(int id);
 void	channel_request(int id, char *service, int wantconfirm);
 void	channel_request_start(int id, char *service, int wantconfirm);
 void	channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
 void	channel_register_cleanup(int id, channel_callback_fn *fn);
 void	channel_register_filter(int id, channel_filter_fn *fn);
 void	channel_cancel_cleanup(int id);
 Channel	*channel_lookup(int id);

 int
 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
     int window, int maxpack, int extended_usage, char *remote_name,
     int nonblock);
 void
 channel_set_fds(int id, int rfd, int wfd, int efd,
     int extusage, int nonblock);

 void	deny_input_open(int type, int plen, void *ctxt);

 void	channel_input_channel_request(int type, int plen, void *ctxt);
 void	channel_input_close(int type, int plen, void *ctxt);
 void	channel_input_close_confirmation(int type, int plen, void *ctxt);
 void	channel_input_data(int type, int plen, void *ctxt);
 void	channel_input_extended_data(int type, int plen, void *ctxt);
 void	channel_input_ieof(int type, int plen, void *ctxt);
 void	channel_input_oclose(int type, int plen, void *ctxt);
 void	channel_input_open_confirmation(int type, int plen, void *ctxt);
 void	channel_input_open_failure(int type, int plen, void *ctxt);
 void	channel_input_port_open(int type, int plen, void *ctxt);
 void	channel_input_window_adjust(int type, int plen, void *ctxt);

 /* Sets specific protocol options. */
 void    channel_set_options(int hostname_in_open);

 /*
  * Allocate a new channel object and set its type and socket.  Remote_name
  * must have been allocated with xmalloc; this will free it when the channel
  * is freed.
  */
 int     channel_allocate(int type, int sock, char *remote_name);

 /* Free the channel and close its socket. */
 void    channel_free(int channel);

 /*
  * Allocate/update select bitmasks and add any bits relevant to channels in
  * select bitmasks.
  */
 void
 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
     int rekeying);

 /*
  * After select, perform any appropriate operations for channels which have
  * events pending.
  */
 void    channel_after_select(fd_set * readset, fd_set * writeset);

 /* If there is data to send to the connection, send some of it now. */
 void    channel_output_poll(void);

 /* Returns true if no channel has too much buffered data. */
 int     channel_not_very_much_buffered_data(void);

 /* This closes any sockets that are listening for connections; this removes
    any unix domain sockets. */
 void    channel_stop_listening(void);

 /*
  * Closes the sockets of all channels.  This is used to close extra file
  * descriptors after a fork.
  */
 void    channel_close_all(void);

 /* Returns true if there is still an open channel over the connection. */
 int     channel_still_open(void);

 /*
  * Returns a string containing a list of all open channels.  The list is
  * suitable for displaying to the user.  It uses crlf instead of newlines.
  * The caller should free the string with xfree.
  */
 char   *channel_open_message(void);

 /*
  * Initiate forwarding of connections to local port "port" through the secure
  * channel to host:port from remote side.
  */
 int
 channel_request_local_forwarding(u_short listen_port,
     const char *host_to_connect, u_short port_to_connect, int gateway_ports);
 int
 channel_request_forwarding(const char *listen_address, u_short listen_port,
     const char *host_to_connect, u_short port_to_connect, int gateway_ports,
     int remote_fwd);

 /*
  * Initiate forwarding of connections to port "port" on remote host through
  * the secure channel to host:port from local side.  This never returns if
  * there was an error.  This registers that open requests for that port are
  * permitted.
  */
 void
 channel_request_remote_forwarding(u_short port, const char *host,
     u_short remote_port);

 /*
  * Permits opening to any host/port if permitted_opens[] is empty.  This is
  * usually called by the server, because the user could connect to any port
  * anyway, and the server has no way to know but to trust the client anyway.
  */
 void    channel_permit_all_opens(void);

 /* Add host/port to list of allowed targets for port forwarding */
 void	channel_add_permitted_opens(char *host, int port);

 /* Flush list */
 void	channel_clear_permitted_opens(void);

 /*
  * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
  * listening for the port, and sends back a success reply (or disconnect
  * message if there was an error).  This never returns if there was an error.
  */
 void    channel_input_port_forward_request(int is_root, int gateway_ports);

 /*
  * Creates a port for X11 connections, and starts listening for it. Returns
  * the display name, or NULL if an error was encountered.
  */
 char   *x11_create_display(int screen);

 /*
  * Creates an internet domain socket for listening for X11 connections.
  * Returns a suitable value for the DISPLAY variable, or NULL if an error
  * occurs.
  */
 char   *x11_create_display_inet(int screen, int x11_display_offset);

 /*
  * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
  * the remote channel number.  We should do whatever we want, and respond
  * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
  */
 void    x11_input_open(int type, int plen, void *ctxt);

 /*
  * Requests forwarding of X11 connections.  This should be called on the
  * client only.
  */
 void    x11_request_forwarding(void);

 /*
  * Requests forwarding for X11 connections, with authentication spoofing.
  * This should be called in the client only.
  */
 void
 x11_request_forwarding_with_spoofing(int client_session_id,
     const char *proto, const char *data);

 /* Sends a message to the server to request authentication fd forwarding. */
 void    auth_request_forwarding(void);

 /*
  * Returns the name of the forwarded authentication socket.  Returns NULL if
  * there is no forwarded authentication socket.  The returned value points to
  * a static buffer.
  */
 char   *auth_get_socket_name(void);

 /*
  * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
  * This starts forwarding authentication requests.
  */
 int     auth_input_request_forwarding(struct passwd * pw);

 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
 void    auth_input_open_request(int type, int plen, void *ctxt);

 /* XXX */
 int	channel_connect_to(const char *host, u_short host_port);
 int	channel_connect_by_listen_adress(u_short listen_port);
 int	x11_connect_display(void);

 int	channel_find_open(void);

 #endif
	/*
	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	* All rights reserved
	*
	* As far as I am concerned, the code I have written for this software
	* can be used freely for any purpose. Any derived versions of this
	* software must be clearly marked as such, and if the derived work is
	* incompatible with the protocol description in the RFC file, it must be
	* called by a name other than "ssh" or "Secure Shell".
	*/
	/*
	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	/* RCSID("$OpenBSD: channels.h,v 1.31 2001/04/13 22:46:53 beck Exp $"); */

	#ifndef CHANNELS_H
	#define CHANNELS_H

	#include "buffer.h"

	/* Definitions for channel types. */
	#define SSH_CHANNEL_FREE 0 /* This channel is free (unused). */
	#define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */
	#define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */
	#define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */
	#define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */
	#define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */
	#define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */
	#define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */
	#define SSH_CHANNEL_INPUT_DRAINING 8 /* sending remaining data to conn */
	#define SSH_CHANNEL_OUTPUT_DRAINING 9 /* sending remaining data to app */
	#define SSH_CHANNEL_LARVAL 10 /* larval session */
	#define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */
	#define SSH_CHANNEL_CONNECTING 12
	#define SSH_CHANNEL_DYNAMIC 13
	#define SSH_CHANNEL_MAX_TYPE 14

	/*
	* Data structure for channel data. This is iniailized in channel_allocate
	* and cleared in channel_free.
	*/
	struct Channel;
	typedef struct Channel Channel;

	typedef void channel_callback_fn(int id, void *arg);
	typedef int channel_filter_fn(struct Channel c, char buf, int len);

	struct Channel {
	int type; /* channel type/state */
	int self; /* my own channel identifier */
	int remote_id; /* channel identifier for remote peer */
	/* peer can be reached over encrypted connection, via packet-sent */
	int istate; /* input from channel (state of receive half) */
	int ostate; /* output to channel (state of transmit half) */
	int flags; /* close sent/rcvd */
	int rfd; /* read fd */
	int wfd; /* write fd */
	int efd; /* extended fd */
	int sock; /* sock fd */
	int isatty; /* rfd is a tty */
	Buffer input; /* data read from socket, to be sent over
	* encrypted connection */
	Buffer output; /* data received over encrypted connection for
	* send on socket */
	Buffer extended;
	char path[200]; /* path for unix domain sockets, or host name
	* for forwards */
	int listening_port; /* port being listened for forwards */
	int host_port; /* remote port to connect for forwards */
	char remote_name; / remote hostname */

	int remote_window;
	int remote_maxpacket;
	int local_window;
	int local_window_max;
	int local_consumed;
	int local_maxpacket;
	int extended_usage;

	char ctype; / type */

	/* callback */
	channel_callback_fn *cb_fn;
	void *cb_arg;
	int cb_event;
	channel_callback_fn *dettach_user;

	/* filter */
	channel_filter_fn *input_filter;
	};

	#define CHAN_EXTENDED_IGNORE 0
	#define CHAN_EXTENDED_READ 1
	#define CHAN_EXTENDED_WRITE 2

	/* default window/packet sizes for tcp/x11-fwd-channel */
	#define CHAN_SES_WINDOW_DEFAULT (32*1024)
	#define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2)
	#define CHAN_TCP_WINDOW_DEFAULT (32*1024)
	#define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
	#define CHAN_X11_WINDOW_DEFAULT (4*1024)
	#define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)


	void channel_open(int id);
	void channel_request(int id, char *service, int wantconfirm);
	void channel_request_start(int id, char *service, int wantconfirm);
	void channel_register_callback(int id, int mtype, channel_callback_fn fn, void arg);
	void channel_register_cleanup(int id, channel_callback_fn *fn);
	void channel_register_filter(int id, channel_filter_fn *fn);
	void channel_cancel_cleanup(int id);
	Channel *channel_lookup(int id);

	int
	channel_new(char *ctype, int type, int rfd, int wfd, int efd,
	int window, int maxpack, int extended_usage, char *remote_name,
	int nonblock);
	void
	channel_set_fds(int id, int rfd, int wfd, int efd,
	int extusage, int nonblock);

	void deny_input_open(int type, int plen, void *ctxt);

	void channel_input_channel_request(int type, int plen, void *ctxt);
	void channel_input_close(int type, int plen, void *ctxt);
	void channel_input_close_confirmation(int type, int plen, void *ctxt);
	void channel_input_data(int type, int plen, void *ctxt);
	void channel_input_extended_data(int type, int plen, void *ctxt);
	void channel_input_ieof(int type, int plen, void *ctxt);
	void channel_input_oclose(int type, int plen, void *ctxt);
	void channel_input_open_confirmation(int type, int plen, void *ctxt);
	void channel_input_open_failure(int type, int plen, void *ctxt);
	void channel_input_port_open(int type, int plen, void *ctxt);
	void channel_input_window_adjust(int type, int plen, void *ctxt);

	/* Sets specific protocol options. */
	void channel_set_options(int hostname_in_open);

	/*
	* Allocate a new channel object and set its type and socket. Remote_name
	* must have been allocated with xmalloc; this will free it when the channel
	* is freed.
	*/
	int channel_allocate(int type, int sock, char *remote_name);

	/* Free the channel and close its socket. */
	void channel_free(int channel);

	/*
	* Allocate/update select bitmasks and add any bits relevant to channels in
	* select bitmasks.
	*/
	void
	channel_prepare_select(fd_set readsetp, fd_set writesetp, int *maxfdp,
	int rekeying);

	/*
	* After select, perform any appropriate operations for channels which have
	* events pending.
	*/
	void channel_after_select(fd_set * readset, fd_set * writeset);

	/* If there is data to send to the connection, send some of it now. */
	void channel_output_poll(void);

	/* Returns true if no channel has too much buffered data. */
	int channel_not_very_much_buffered_data(void);

	/* This closes any sockets that are listening for connections; this removes
	any unix domain sockets. */
	void channel_stop_listening(void);

	/*
	* Closes the sockets of all channels. This is used to close extra file
	* descriptors after a fork.
	*/
	void channel_close_all(void);

	/* Returns true if there is still an open channel over the connection. */
	int channel_still_open(void);

	/*
	* Returns a string containing a list of all open channels. The list is
	* suitable for displaying to the user. It uses crlf instead of newlines.
	* The caller should free the string with xfree.
	*/
	char *channel_open_message(void);

	/*
	* Initiate forwarding of connections to local port "port" through the secure
	* channel to host:port from remote side.
	*/
	int
	channel_request_local_forwarding(u_short listen_port,
	const char *host_to_connect, u_short port_to_connect, int gateway_ports);
	int
	channel_request_forwarding(const char *listen_address, u_short listen_port,
	const char *host_to_connect, u_short port_to_connect, int gateway_ports,
	int remote_fwd);

	/*
	* Initiate forwarding of connections to port "port" on remote host through
	* the secure channel to host:port from local side. This never returns if
	* there was an error. This registers that open requests for that port are
	* permitted.
	*/
	void
	channel_request_remote_forwarding(u_short port, const char *host,
	u_short remote_port);

	/*
	* Permits opening to any host/port if permitted_opens[] is empty. This is
	* usually called by the server, because the user could connect to any port
	* anyway, and the server has no way to know but to trust the client anyway.
	*/
	void channel_permit_all_opens(void);

	/* Add host/port to list of allowed targets for port forwarding */
	void channel_add_permitted_opens(char *host, int port);

	/* Flush list */
	void channel_clear_permitted_opens(void);

	/*
	* This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
	* listening for the port, and sends back a success reply (or disconnect
	* message if there was an error). This never returns if there was an error.
	*/
	void channel_input_port_forward_request(int is_root, int gateway_ports);

	/*
	* Creates a port for X11 connections, and starts listening for it. Returns
	* the display name, or NULL if an error was encountered.
	*/
	char *x11_create_display(int screen);

	/*
	* Creates an internet domain socket for listening for X11 connections.
	* Returns a suitable value for the DISPLAY variable, or NULL if an error
	* occurs.
	*/
	char *x11_create_display_inet(int screen, int x11_display_offset);

	/*
	* This is called when SSH_SMSG_X11_OPEN is received. The packet contains
	* the remote channel number. We should do whatever we want, and respond
	* with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
	*/
	void x11_input_open(int type, int plen, void *ctxt);

	/*
	* Requests forwarding of X11 connections. This should be called on the
	* client only.
	*/
	void x11_request_forwarding(void);

	/*
	* Requests forwarding for X11 connections, with authentication spoofing.
	* This should be called in the client only.
	*/
	void
	x11_request_forwarding_with_spoofing(int client_session_id,
	const char proto, const char data);

	/* Sends a message to the server to request authentication fd forwarding. */
	void auth_request_forwarding(void);

	/*
	* Returns the name of the forwarded authentication socket. Returns NULL if
	* there is no forwarded authentication socket. The returned value points to
	* a static buffer.
	*/
	char *auth_get_socket_name(void);

	/*
	* This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
	* This starts forwarding authentication requests.
	*/
	int auth_input_request_forwarding(struct passwd * pw);

	/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
	void auth_input_open_request(int type, int plen, void *ctxt);

	/* XXX */
	int channel_connect_to(const char *host, u_short host_port);
	int channel_connect_by_listen_adress(u_short listen_port);
	int x11_connect_display(void);

	int channel_find_open(void);

	#endif