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openssh/channels.h
Damien Miller f6dff7cd2f - djm@cvs.openbsd.org 2011/09/09 22:46:44 
[channels.c channels.h clientloop.h mux.c ssh.c]
     support for cancelling local and remote port forwards via the multiplex
     socket. Use ssh -O cancel -L xx:xx:xx -R yy:yy:yy user@host" to request
     the cancellation of the specified forwardings; ok markus@
2011-09-22 21:38:52 +10:00

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/* $OpenBSD: channels.h,v 1.106 2011/09/09 22:46:44 djm Exp $ */
/*
* 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) 1999, 2000, 2001, 2002 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.
*/
#ifndef CHANNEL_H
#define CHANNEL_H
/* Definitions for channel types. */
#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_ZOMBIE 14 /* Almost dead. */
#define SSH_CHANNEL_MUX_LISTENER 15 /* Listener for mux conn. */
#define SSH_CHANNEL_MUX_CLIENT 16 /* Conn. to mux slave */
#define SSH_CHANNEL_MAX_TYPE 17
struct Channel;
typedef struct Channel Channel;
typedef void channel_open_fn(int, int, void *);
typedef void channel_callback_fn(int, void *);
typedef int channel_infilter_fn(struct Channel *, char *, int);
typedef void channel_filter_cleanup_fn(int, void *);
typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
/* Channel success/failure callbacks */
typedef void channel_confirm_cb(int, struct Channel *, void *);
typedef void channel_confirm_abandon_cb(struct Channel *, void *);
struct channel_confirm {
TAILQ_ENTRY(channel_confirm) entry;
channel_confirm_cb *cb;
channel_confirm_abandon_cb *abandon_cb;
void *ctx;
};
TAILQ_HEAD(channel_confirms, channel_confirm);
/* Context for non-blocking connects */
struct channel_connect {
char *host;
int port;
struct addrinfo *ai, *aitop;
};
/* Callbacks for mux channels back into client-specific code */
typedef int mux_callback_fn(struct Channel *);
struct Channel {
int type; /* channel type/state */
int self; /* my own channel identifier */
int remote_id; /* channel identifier for remote peer */
u_int istate; /* input from channel (state of receive half) */
u_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 ctl_chan; /* control channel (multiplexed connections) */
int isatty; /* rfd is a tty */
int wfd_isatty; /* wfd is a tty */
int client_tty; /* (client) TTY has been requested */
int force_drain; /* force close on iEOF */
int delayed; /* post-select handlers for newly created
* channels are delayed until the first call
* to a matching pre-select handler.
* this way post-select handlers are not
* accidenly called if a FD gets reused */
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;
/* path for unix domain sockets, or host name for forwards */
int listening_port; /* port being listened for forwards */
char *listening_addr; /* addr being listened for forwards */
int host_port; /* remote port to connect for forwards */
char *remote_name; /* remote hostname */
u_int remote_window;
u_int remote_maxpacket;
u_int local_window;
u_int local_window_max;
u_int local_consumed;
u_int local_maxpacket;
int extended_usage;
int single_connection;
char *ctype; /* type */
/* callback */
channel_open_fn *open_confirm;
void *open_confirm_ctx;
channel_callback_fn *detach_user;
int detach_close;
struct channel_confirms status_confirms;
/* filter */
channel_infilter_fn *input_filter;
channel_outfilter_fn *output_filter;
void *filter_ctx;
channel_filter_cleanup_fn *filter_cleanup;
/* keep boundaries */
int datagram;
/* non-blocking connect */
struct channel_connect connect_ctx;
/* multiplexing protocol hook, called for each packet received */
mux_callback_fn *mux_rcb;
void *mux_ctx;
int mux_pause;
};
#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_PACKET_DEFAULT (32*1024)
#define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
#define CHAN_TCP_PACKET_DEFAULT (32*1024)
#define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
#define CHAN_X11_PACKET_DEFAULT (16*1024)
#define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
/* possible input states */
#define CHAN_INPUT_OPEN 0
#define CHAN_INPUT_WAIT_DRAIN 1
#define CHAN_INPUT_WAIT_OCLOSE 2
#define CHAN_INPUT_CLOSED 3
/* possible output states */
#define CHAN_OUTPUT_OPEN 0
#define CHAN_OUTPUT_WAIT_DRAIN 1
#define CHAN_OUTPUT_WAIT_IEOF 2
#define CHAN_OUTPUT_CLOSED 3
#define CHAN_CLOSE_SENT 0x01
#define CHAN_CLOSE_RCVD 0x02
#define CHAN_EOF_SENT 0x04
#define CHAN_EOF_RCVD 0x08
#define CHAN_LOCAL 0x10
#define CHAN_RBUF 16*1024
/* check whether 'efd' is still in use */
#define CHANNEL_EFD_INPUT_ACTIVE(c) \
(compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
(c->efd != -1 || \
buffer_len(&c->extended) > 0))
#define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
(compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
buffer_len(&c->extended) > 0))
/* channel management */
Channel *channel_by_id(int);
Channel *channel_lookup(int);
Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
void channel_set_fds(int, int, int, int, int, int, int, u_int);
void channel_free(Channel *);
void channel_free_all(void);
void channel_stop_listening(void);
void channel_send_open(int);
void channel_request_start(int, char *, int);
void channel_register_cleanup(int, channel_callback_fn *, int);
void channel_register_open_confirm(int, channel_open_fn *, void *);
void channel_register_filter(int, channel_infilter_fn *,
channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
void channel_register_status_confirm(int, channel_confirm_cb *,
channel_confirm_abandon_cb *, void *);
void channel_cancel_cleanup(int);
int channel_close_fd(int *);
void channel_send_window_changes(void);
/* protocol handler */
void channel_input_close(int, u_int32_t, void *);
void channel_input_close_confirmation(int, u_int32_t, void *);
void channel_input_data(int, u_int32_t, void *);
void channel_input_extended_data(int, u_int32_t, void *);
void channel_input_ieof(int, u_int32_t, void *);
void channel_input_oclose(int, u_int32_t, void *);
void channel_input_open_confirmation(int, u_int32_t, void *);
void channel_input_open_failure(int, u_int32_t, void *);
void channel_input_port_open(int, u_int32_t, void *);
void channel_input_window_adjust(int, u_int32_t, void *);
void channel_input_status_confirm(int, u_int32_t, void *);
/* file descriptor handling (read/write) */
void channel_prepare_select(fd_set **, fd_set **, int *, u_int*, int);
void channel_after_select(fd_set *, fd_set *);
void channel_output_poll(void);
int channel_not_very_much_buffered_data(void);
void channel_close_all(void);
int channel_still_open(void);
char *channel_open_message(void);
int channel_find_open(void);
/* tcp forwarding */
void channel_set_af(int af);
void channel_permit_all_opens(void);
void channel_add_permitted_opens(char *, int);
int channel_add_adm_permitted_opens(char *, int);
void channel_clear_permitted_opens(void);
void channel_clear_adm_permitted_opens(void);
void channel_print_adm_permitted_opens(void);
int channel_input_port_forward_request(int, int);
Channel *channel_connect_to(const char *, u_short, char *, char *);
Channel *channel_connect_stdio_fwd(const char*, u_short, int, int);
Channel *channel_connect_by_listen_address(u_short, char *, char *);
int channel_request_remote_forwarding(const char *, u_short,
const char *, u_short);
int channel_setup_local_fwd_listener(const char *, u_short,
const char *, u_short, int);
int channel_request_rforward_cancel(const char *host, u_short port);
int channel_setup_remote_fwd_listener(const char *, u_short, int *, int);
int channel_cancel_rport_listener(const char *, u_short);
int channel_cancel_lport_listener(const char *, u_short, u_short, int);
/* x11 forwarding */
int x11_connect_display(void);
int x11_create_display_inet(int, int, int, u_int *, int **);
void x11_input_open(int, u_int32_t, void *);
void x11_request_forwarding_with_spoofing(int, const char *, const char *,
const char *, int);
void deny_input_open(int, u_int32_t, void *);
/* agent forwarding */
void auth_request_forwarding(void);
/* channel close */
int chan_is_dead(Channel *, int);
void chan_mark_dead(Channel *);
/* channel events */
void chan_rcvd_oclose(Channel *);
void chan_rcvd_eow(Channel *); /* SSH2-only */
void chan_read_failed(Channel *);
void chan_ibuf_empty(Channel *);
void chan_rcvd_ieof(Channel *);
void chan_write_failed(Channel *);
void chan_obuf_empty(Channel *);
#endif
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