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openssh/channels.h
Damien Miller d530f5f471 - djm@cvs.openbsd.org 2010/05/14 23:29:23 
[channels.c channels.h mux.c ssh.c]
     Pause the mux channel while waiting for reply from aynch callbacks.
     Prevents misordering of replies if new requests arrive while waiting.

     Extend channel open confirm callback to allow signalling failure
     conditions as well as success. Use this to 1) fix a memory leak, 2)
     start using the above pause mechanism and 3) delay sending a success/
     failure message on mux slave session open until we receive a reply from
     the server.

     motivated by and with feedback from markus@
2010-05-21 14:57:10 +10:00

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/* $OpenBSD: channels.h,v 1.104 2010/05/14 23:29:23 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 */
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);
void 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);
/* 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 *);
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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