Some notable changes, from upstream's release notes: - sshd(8): Remove support for obsolete "host/port" syntax. - ssh(1): When prompting whether to record a new host key, accept the key fingerprint as a synonym for "yes". - ssh-keygen(1): when acting as a CA and signing certificates with an RSA key, default to using the rsa-sha2-512 signature algorithm. - ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa" (RSA/SHA1) algorithm from those accepted for certificate signatures. - ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F support to provide address-space isolation for token middleware libraries (including the internal one). - ssh(1): this release enables UpdateHostkeys by default subject to some conservative preconditions. - scp(1): this release changes the behaviour of remote to remote copies (e.g. "scp host-a:/path host-b:") to transfer through the local host by default. - scp(1): experimental support for transfers using the SFTP protocol as a replacement for the venerable SCP/RCP protocol that it has traditionally used. Additional integration work is needed to support FIDO/U2F in the base system. Deprecation Notice ------------------ OpenSSH will disable the ssh-rsa signature scheme by default in the next release. Reviewed by: imp MFC after: 1 month Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D29985
367 lines
14 KiB
C
367 lines
14 KiB
C
/* $OpenBSD: channels.h,v 1.138 2021/05/19 01:24:05 djm Exp $ */
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/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*/
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/*
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* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef CHANNEL_H
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#define CHANNEL_H
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/* Definitions for channel types. */
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#define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */
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#define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */
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#define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */
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#define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */
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#define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */
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#define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */
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#define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */
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#define SSH_CHANNEL_LARVAL 10 /* larval session */
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#define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */
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#define SSH_CHANNEL_CONNECTING 12
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#define SSH_CHANNEL_DYNAMIC 13
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#define SSH_CHANNEL_ZOMBIE 14 /* Almost dead. */
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#define SSH_CHANNEL_MUX_LISTENER 15 /* Listener for mux conn. */
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#define SSH_CHANNEL_MUX_CLIENT 16 /* Conn. to mux client */
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#define SSH_CHANNEL_ABANDONED 17 /* Abandoned session, eg mux */
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#define SSH_CHANNEL_UNIX_LISTENER 18 /* Listening on a domain socket. */
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#define SSH_CHANNEL_RUNIX_LISTENER 19 /* Listening to a R-style domain socket. */
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#define SSH_CHANNEL_MUX_PROXY 20 /* proxy channel for mux-client */
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#define SSH_CHANNEL_RDYNAMIC_OPEN 21 /* reverse SOCKS, parsing request */
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#define SSH_CHANNEL_RDYNAMIC_FINISH 22 /* reverse SOCKS, finishing connect */
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#define SSH_CHANNEL_MAX_TYPE 23
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#define CHANNEL_CANCEL_PORT_STATIC -1
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/* nonblocking flags for channel_new */
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#define CHANNEL_NONBLOCK_LEAVE 0 /* don't modify non-blocking state */
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#define CHANNEL_NONBLOCK_SET 1 /* set non-blocking state */
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#define CHANNEL_NONBLOCK_STDIO 2 /* set non-blocking and restore on close */
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/* c->restore_block mask flags */
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#define CHANNEL_RESTORE_RFD 0x01
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#define CHANNEL_RESTORE_WFD 0x02
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#define CHANNEL_RESTORE_EFD 0x04
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/* TCP forwarding */
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#define FORWARD_DENY 0
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#define FORWARD_REMOTE (1)
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#define FORWARD_LOCAL (1<<1)
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#define FORWARD_ALLOW (FORWARD_REMOTE|FORWARD_LOCAL)
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#define FORWARD_ADM 0x100
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#define FORWARD_USER 0x101
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struct ssh;
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struct Channel;
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typedef struct Channel Channel;
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struct fwd_perm_list;
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typedef void channel_open_fn(struct ssh *, int, int, void *);
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typedef void channel_callback_fn(struct ssh *, int, void *);
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typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int);
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typedef void channel_filter_cleanup_fn(struct ssh *, int, void *);
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typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *,
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u_char **, size_t *);
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/* Channel success/failure callbacks */
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typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *);
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typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *);
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struct channel_confirm {
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TAILQ_ENTRY(channel_confirm) entry;
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channel_confirm_cb *cb;
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channel_confirm_abandon_cb *abandon_cb;
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void *ctx;
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};
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TAILQ_HEAD(channel_confirms, channel_confirm);
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/* Context for non-blocking connects */
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struct channel_connect {
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char *host;
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int port;
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struct addrinfo *ai, *aitop;
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};
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/* Callbacks for mux channels back into client-specific code */
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typedef int mux_callback_fn(struct ssh *, struct Channel *);
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/*
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* NB. channel IDs on the wire and in c->remote_id are uint32, but local
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* channel IDs (e.g. c->self) only ever use the int32 subset of this range,
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* because we use local channel ID -1 for housekeeping. Remote channels have
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* a dedicated "have_remote_id" flag to indicate their validity.
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*/
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struct Channel {
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int type; /* channel type/state */
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int self; /* my own channel identifier */
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uint32_t remote_id; /* channel identifier for remote peer */
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int have_remote_id; /* non-zero if remote_id is valid */
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u_int istate; /* input from channel (state of receive half) */
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u_int ostate; /* output to channel (state of transmit half) */
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int flags; /* close sent/rcvd */
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int rfd; /* read fd */
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int wfd; /* write fd */
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int efd; /* extended fd */
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int sock; /* sock fd */
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int ctl_chan; /* control channel (multiplexed connections) */
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int isatty; /* rfd is a tty */
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#ifdef _AIX
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int wfd_isatty; /* wfd is a tty */
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#endif
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int client_tty; /* (client) TTY has been requested */
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int force_drain; /* force close on iEOF */
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time_t notbefore; /* Pause IO until deadline (time_t) */
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int delayed; /* post-select handlers for newly created
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* channels are delayed until the first call
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* to a matching pre-select handler.
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* this way post-select handlers are not
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* accidentally called if a FD gets reused */
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int restore_block; /* fd mask to restore blocking status */
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struct sshbuf *input; /* data read from socket, to be sent over
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* encrypted connection */
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struct sshbuf *output; /* data received over encrypted connection for
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* send on socket */
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struct sshbuf *extended;
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char *path;
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/* path for unix domain sockets, or host name for forwards */
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int listening_port; /* port being listened for forwards */
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char *listening_addr; /* addr being listened for forwards */
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int host_port; /* remote port to connect for forwards */
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char *remote_name; /* remote hostname */
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u_int remote_window;
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u_int remote_maxpacket;
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u_int local_window;
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u_int local_window_max;
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u_int local_consumed;
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u_int local_maxpacket;
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int extended_usage;
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int single_connection;
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char *ctype; /* type */
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/* callback */
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channel_open_fn *open_confirm;
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void *open_confirm_ctx;
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channel_callback_fn *detach_user;
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int detach_close;
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struct channel_confirms status_confirms;
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/* filter */
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channel_infilter_fn *input_filter;
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channel_outfilter_fn *output_filter;
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void *filter_ctx;
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channel_filter_cleanup_fn *filter_cleanup;
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/* keep boundaries */
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int datagram;
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/* non-blocking connect */
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/* XXX make this a pointer so the structure can be opaque */
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struct channel_connect connect_ctx;
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/* multiplexing protocol hook, called for each packet received */
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mux_callback_fn *mux_rcb;
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void *mux_ctx;
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int mux_pause;
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int mux_downstream_id;
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};
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#define CHAN_EXTENDED_IGNORE 0
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#define CHAN_EXTENDED_READ 1
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#define CHAN_EXTENDED_WRITE 2
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/* default window/packet sizes for tcp/x11-fwd-channel */
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#define CHAN_SES_PACKET_DEFAULT (32*1024)
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#define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
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#define CHAN_TCP_PACKET_DEFAULT (32*1024)
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#define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
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#define CHAN_X11_PACKET_DEFAULT (16*1024)
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#define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
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/* possible input states */
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#define CHAN_INPUT_OPEN 0
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#define CHAN_INPUT_WAIT_DRAIN 1
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#define CHAN_INPUT_WAIT_OCLOSE 2
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#define CHAN_INPUT_CLOSED 3
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/* possible output states */
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#define CHAN_OUTPUT_OPEN 0
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#define CHAN_OUTPUT_WAIT_DRAIN 1
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#define CHAN_OUTPUT_WAIT_IEOF 2
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#define CHAN_OUTPUT_CLOSED 3
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#define CHAN_CLOSE_SENT 0x01
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#define CHAN_CLOSE_RCVD 0x02
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#define CHAN_EOF_SENT 0x04
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#define CHAN_EOF_RCVD 0x08
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#define CHAN_LOCAL 0x10
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/* Read buffer size */
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#define CHAN_RBUF (16*1024)
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/* Maximum channel input buffer size */
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#define CHAN_INPUT_MAX (16*1024*1024)
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/* Hard limit on number of channels */
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#define CHANNELS_MAX_CHANNELS (16*1024)
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/* check whether 'efd' is still in use */
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#define CHANNEL_EFD_INPUT_ACTIVE(c) \
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(c->extended_usage == CHAN_EXTENDED_READ && \
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(c->efd != -1 || \
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sshbuf_len(c->extended) > 0))
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#define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
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(c->extended_usage == CHAN_EXTENDED_WRITE && \
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c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
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sshbuf_len(c->extended) > 0))
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/* Add channel management structures to SSH transport instance */
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void channel_init_channels(struct ssh *ssh);
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/* channel management */
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Channel *channel_by_id(struct ssh *, int);
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Channel *channel_by_remote_id(struct ssh *, u_int);
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Channel *channel_lookup(struct ssh *, int);
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Channel *channel_new(struct ssh *, char *, int, int, int, int,
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u_int, u_int, int, char *, int);
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void channel_set_fds(struct ssh *, int, int, int, int, int,
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int, int, u_int);
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void channel_free(struct ssh *, Channel *);
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void channel_free_all(struct ssh *);
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void channel_stop_listening(struct ssh *);
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void channel_send_open(struct ssh *, int);
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void channel_request_start(struct ssh *, int, char *, int);
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void channel_register_cleanup(struct ssh *, int,
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channel_callback_fn *, int);
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void channel_register_open_confirm(struct ssh *, int,
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channel_open_fn *, void *);
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void channel_register_filter(struct ssh *, int, channel_infilter_fn *,
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channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
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void channel_register_status_confirm(struct ssh *, int,
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channel_confirm_cb *, channel_confirm_abandon_cb *, void *);
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void channel_cancel_cleanup(struct ssh *, int);
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int channel_close_fd(struct ssh *, Channel *, int *);
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void channel_send_window_changes(struct ssh *);
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/* mux proxy support */
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int channel_proxy_downstream(struct ssh *, Channel *mc);
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int channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *);
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/* protocol handler */
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int channel_input_data(int, u_int32_t, struct ssh *);
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int channel_input_extended_data(int, u_int32_t, struct ssh *);
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int channel_input_ieof(int, u_int32_t, struct ssh *);
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int channel_input_oclose(int, u_int32_t, struct ssh *);
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int channel_input_open_confirmation(int, u_int32_t, struct ssh *);
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int channel_input_open_failure(int, u_int32_t, struct ssh *);
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int channel_input_port_open(int, u_int32_t, struct ssh *);
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int channel_input_window_adjust(int, u_int32_t, struct ssh *);
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int channel_input_status_confirm(int, u_int32_t, struct ssh *);
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/* file descriptor handling (read/write) */
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void channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *,
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u_int*, time_t*);
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void channel_after_select(struct ssh *, fd_set *, fd_set *);
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void channel_output_poll(struct ssh *);
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int channel_not_very_much_buffered_data(struct ssh *);
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void channel_close_all(struct ssh *);
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int channel_still_open(struct ssh *);
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const char *channel_format_extended_usage(const Channel *);
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char *channel_open_message(struct ssh *);
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int channel_find_open(struct ssh *);
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/* tcp forwarding */
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struct Forward;
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struct ForwardOptions;
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void channel_set_af(struct ssh *, int af);
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void channel_permit_all(struct ssh *, int);
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void channel_add_permission(struct ssh *, int, int, char *, int);
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void channel_clear_permission(struct ssh *, int, int);
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void channel_disable_admin(struct ssh *, int);
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void channel_update_permission(struct ssh *, int, int);
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Channel *channel_connect_to_port(struct ssh *, const char *, u_short,
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char *, char *, int *, const char **);
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Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *);
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Channel *channel_connect_stdio_fwd(struct ssh *, const char*,
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u_short, int, int, int);
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Channel *channel_connect_by_listen_address(struct ssh *, const char *,
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u_short, char *, char *);
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Channel *channel_connect_by_listen_path(struct ssh *, const char *,
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char *, char *);
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int channel_request_remote_forwarding(struct ssh *, struct Forward *);
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int channel_setup_local_fwd_listener(struct ssh *, struct Forward *,
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struct ForwardOptions *);
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int channel_request_rforward_cancel(struct ssh *, struct Forward *);
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int channel_setup_remote_fwd_listener(struct ssh *, struct Forward *,
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int *, struct ForwardOptions *);
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int channel_cancel_rport_listener(struct ssh *, struct Forward *);
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int channel_cancel_lport_listener(struct ssh *, struct Forward *,
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int, struct ForwardOptions *);
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int permitopen_port(const char *);
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/* x11 forwarding */
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void channel_set_x11_refuse_time(struct ssh *, u_int);
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int x11_connect_display(struct ssh *);
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int x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **);
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void x11_request_forwarding_with_spoofing(struct ssh *, int,
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const char *, const char *, const char *, int);
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/* channel close */
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int chan_is_dead(struct ssh *, Channel *, int);
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void chan_mark_dead(struct ssh *, Channel *);
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/* channel events */
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void chan_rcvd_oclose(struct ssh *, Channel *);
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void chan_rcvd_eow(struct ssh *, Channel *);
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void chan_read_failed(struct ssh *, Channel *);
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void chan_ibuf_empty(struct ssh *, Channel *);
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void chan_rcvd_ieof(struct ssh *, Channel *);
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void chan_write_failed(struct ssh *, Channel *);
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void chan_obuf_empty(struct ssh *, Channel *);
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#endif
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