channels.h - third_party/openssh-portable - Git at Google

 /* RCSID("$OpenBSD: channels.h,v 1.14 2000/06/20 01:39:40 markus Exp $"); */

 #ifndef CHANNELS_H
 #define CHANNELS_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_MAX_TYPE		11

 /*
  * Data structure for channel data.  This is iniailized in channel_allocate
  * and cleared in channel_free.
  */
 typedef void channel_callback_fn(int id, void *arg);

 typedef 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 */
 	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;
 }       Channel;

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

 void	channel_set_fds(int id, int rfd, int wfd, int efd, int extusage);
 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_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);

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

 /* 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);

 /* Add any bits relevant to channels in select bitmasks. */
 void    channel_prepare_select(fd_set * readset, fd_set * writeset);

 /*
  * 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 the maximum file descriptor number used by the channels. */
 int     channel_max_fd(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.  This never returns if there was an
  * error.
  */
 void
 channel_request_local_forwarding(u_short port, const char *host,
     u_short remote_port, int gateway_ports);

 /*
  * 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 in SSH_MSG_PORT_OPEN.  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);

 /*
  * 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);

 /*
  * 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);

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

 #endif
	/* RCSID("$OpenBSD: channels.h,v 1.14 2000/06/20 01:39:40 markus Exp $"); */

	#ifndef CHANNELS_H
	#define CHANNELS_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_MAX_TYPE 11

	/*
	* Data structure for channel data. This is iniailized in channel_allocate
	* and cleared in channel_free.
	*/
	typedef void channel_callback_fn(int id, void *arg);

	typedef 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 */
	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;
	} Channel;

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

	void channel_set_fds(int id, int rfd, int wfd, int efd, int extusage);
	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_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);

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

	/* 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);

	/* Add any bits relevant to channels in select bitmasks. */
	void channel_prepare_select(fd_set * readset, fd_set * writeset);

	/*
	* 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 the maximum file descriptor number used by the channels. */
	int channel_max_fd(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. This never returns if there was an
	* error.
	*/
	void
	channel_request_local_forwarding(u_short port, const char *host,
	u_short remote_port, int gateway_ports);

	/*
	* 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 in SSH_MSG_PORT_OPEN. 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);

	/*
	* 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);

	/*
	* 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);

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

	#endif