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openssh/channels.h

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/*
* 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 1.22 2000/10/27 07:48:22 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.
*/
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 */
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);
void channel_input_open(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);
/* 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, 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 x11_connect_display(void);
#endif
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