channels.h revision 295367
1/* $OpenBSD: channels.h,v 1.118 2015/07/01 02:26:31 djm Exp $ */
2
3/*
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 *                    All rights reserved
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose.  Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 */
14/*
15 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 *    notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 *    notice, this list of conditions and the following disclaimer in the
24 *    documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 */
37
38#ifndef CHANNEL_H
39#define CHANNEL_H
40
41/* Definitions for channel types. */
42#define SSH_CHANNEL_X11_LISTENER	1	/* Listening for inet X11 conn. */
43#define SSH_CHANNEL_PORT_LISTENER	2	/* Listening on a port. */
44#define SSH_CHANNEL_OPENING		3	/* waiting for confirmation */
45#define SSH_CHANNEL_OPEN		4	/* normal open two-way channel */
46#define SSH_CHANNEL_CLOSED		5	/* waiting for close confirmation */
47#define SSH_CHANNEL_AUTH_SOCKET		6	/* authentication socket */
48#define SSH_CHANNEL_X11_OPEN		7	/* reading first X11 packet */
49#define SSH_CHANNEL_INPUT_DRAINING	8	/* sending remaining data to conn */
50#define SSH_CHANNEL_OUTPUT_DRAINING	9	/* sending remaining data to app */
51#define SSH_CHANNEL_LARVAL		10	/* larval session */
52#define SSH_CHANNEL_RPORT_LISTENER	11	/* Listening to a R-style port  */
53#define SSH_CHANNEL_CONNECTING		12
54#define SSH_CHANNEL_DYNAMIC		13
55#define SSH_CHANNEL_ZOMBIE		14	/* Almost dead. */
56#define SSH_CHANNEL_MUX_LISTENER	15	/* Listener for mux conn. */
57#define SSH_CHANNEL_MUX_CLIENT		16	/* Conn. to mux slave */
58#define SSH_CHANNEL_ABANDONED		17	/* Abandoned session, eg mux */
59#define SSH_CHANNEL_UNIX_LISTENER	18	/* Listening on a domain socket. */
60#define SSH_CHANNEL_RUNIX_LISTENER	19	/* Listening to a R-style domain socket. */
61#define SSH_CHANNEL_MAX_TYPE		20
62
63#define CHANNEL_CANCEL_PORT_STATIC	-1
64
65struct Channel;
66typedef struct Channel Channel;
67
68typedef void channel_open_fn(int, int, void *);
69typedef void channel_callback_fn(int, void *);
70typedef int channel_infilter_fn(struct Channel *, char *, int);
71typedef void channel_filter_cleanup_fn(int, void *);
72typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
73
74/* Channel success/failure callbacks */
75typedef void channel_confirm_cb(int, struct Channel *, void *);
76typedef void channel_confirm_abandon_cb(struct Channel *, void *);
77struct channel_confirm {
78	TAILQ_ENTRY(channel_confirm) entry;
79	channel_confirm_cb *cb;
80	channel_confirm_abandon_cb *abandon_cb;
81	void *ctx;
82};
83TAILQ_HEAD(channel_confirms, channel_confirm);
84
85/* Context for non-blocking connects */
86struct channel_connect {
87	char *host;
88	int port;
89	struct addrinfo *ai, *aitop;
90};
91
92/* Callbacks for mux channels back into client-specific code */
93typedef int mux_callback_fn(struct Channel *);
94
95struct Channel {
96	int     type;		/* channel type/state */
97	int     self;		/* my own channel identifier */
98	int     remote_id;	/* channel identifier for remote peer */
99	u_int   istate;		/* input from channel (state of receive half) */
100	u_int   ostate;		/* output to channel  (state of transmit half) */
101	int     flags;		/* close sent/rcvd */
102	int     rfd;		/* read fd */
103	int     wfd;		/* write fd */
104	int     efd;		/* extended fd */
105	int     sock;		/* sock fd */
106	int     ctl_chan;	/* control channel (multiplexed connections) */
107	int     isatty;		/* rfd is a tty */
108#ifdef _AIX
109	int     wfd_isatty;	/* wfd is a tty */
110#endif
111	int	client_tty;	/* (client) TTY has been requested */
112	int     force_drain;	/* force close on iEOF */
113	time_t	notbefore;	/* Pause IO until deadline (time_t) */
114	int     delayed;	/* post-select handlers for newly created
115				 * channels are delayed until the first call
116				 * to a matching pre-select handler.
117				 * this way post-select handlers are not
118				 * accidentally called if a FD gets reused */
119	Buffer  input;		/* data read from socket, to be sent over
120				 * encrypted connection */
121	Buffer  output;		/* data received over encrypted connection for
122				 * send on socket */
123	Buffer  extended;
124	char    *path;
125		/* path for unix domain sockets, or host name for forwards */
126	int     listening_port;	/* port being listened for forwards */
127	char   *listening_addr;	/* addr being listened for forwards */
128	int     host_port;	/* remote port to connect for forwards */
129	char   *remote_name;	/* remote hostname */
130
131	u_int	remote_window;
132	u_int	remote_maxpacket;
133	u_int	local_window;
134	u_int	local_window_max;
135	u_int	local_consumed;
136	u_int	local_maxpacket;
137	int     extended_usage;
138	int	single_connection;
139
140	char   *ctype;		/* type */
141
142	/* callback */
143	channel_open_fn		*open_confirm;
144	void			*open_confirm_ctx;
145	channel_callback_fn	*detach_user;
146	int			detach_close;
147	struct channel_confirms	status_confirms;
148
149	/* filter */
150	channel_infilter_fn	*input_filter;
151	channel_outfilter_fn	*output_filter;
152	void			*filter_ctx;
153	channel_filter_cleanup_fn *filter_cleanup;
154
155	/* keep boundaries */
156	int     		datagram;
157
158	/* non-blocking connect */
159	struct channel_connect	connect_ctx;
160
161	/* multiplexing protocol hook, called for each packet received */
162	mux_callback_fn		*mux_rcb;
163	void			*mux_ctx;
164	int			mux_pause;
165};
166
167#define CHAN_EXTENDED_IGNORE		0
168#define CHAN_EXTENDED_READ		1
169#define CHAN_EXTENDED_WRITE		2
170
171/* default window/packet sizes for tcp/x11-fwd-channel */
172#define CHAN_SES_PACKET_DEFAULT	(32*1024)
173#define CHAN_SES_WINDOW_DEFAULT	(64*CHAN_SES_PACKET_DEFAULT)
174#define CHAN_TCP_PACKET_DEFAULT	(32*1024)
175#define CHAN_TCP_WINDOW_DEFAULT	(64*CHAN_TCP_PACKET_DEFAULT)
176#define CHAN_X11_PACKET_DEFAULT	(16*1024)
177#define CHAN_X11_WINDOW_DEFAULT	(4*CHAN_X11_PACKET_DEFAULT)
178
179/* possible input states */
180#define CHAN_INPUT_OPEN			0
181#define CHAN_INPUT_WAIT_DRAIN		1
182#define CHAN_INPUT_WAIT_OCLOSE		2
183#define CHAN_INPUT_CLOSED		3
184
185/* possible output states */
186#define CHAN_OUTPUT_OPEN		0
187#define CHAN_OUTPUT_WAIT_DRAIN		1
188#define CHAN_OUTPUT_WAIT_IEOF		2
189#define CHAN_OUTPUT_CLOSED		3
190
191#define CHAN_CLOSE_SENT			0x01
192#define CHAN_CLOSE_RCVD			0x02
193#define CHAN_EOF_SENT			0x04
194#define CHAN_EOF_RCVD			0x08
195#define CHAN_LOCAL			0x10
196
197#define CHAN_RBUF	16*1024
198
199/* check whether 'efd' is still in use */
200#define CHANNEL_EFD_INPUT_ACTIVE(c) \
201	(compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
202	(c->efd != -1 || \
203	buffer_len(&c->extended) > 0))
204#define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
205	(compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
206	c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
207	buffer_len(&c->extended) > 0))
208
209/* channel management */
210
211Channel	*channel_by_id(int);
212Channel	*channel_lookup(int);
213Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
214void	 channel_set_fds(int, int, int, int, int, int, int, u_int);
215void	 channel_free(Channel *);
216void	 channel_free_all(void);
217void	 channel_stop_listening(void);
218
219void	 channel_send_open(int);
220void	 channel_request_start(int, char *, int);
221void	 channel_register_cleanup(int, channel_callback_fn *, int);
222void	 channel_register_open_confirm(int, channel_open_fn *, void *);
223void	 channel_register_filter(int, channel_infilter_fn *,
224    channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
225void	 channel_register_status_confirm(int, channel_confirm_cb *,
226    channel_confirm_abandon_cb *, void *);
227void	 channel_cancel_cleanup(int);
228int	 channel_close_fd(int *);
229void	 channel_send_window_changes(void);
230
231/* protocol handler */
232
233int	 channel_input_close(int, u_int32_t, void *);
234int	 channel_input_close_confirmation(int, u_int32_t, void *);
235int	 channel_input_data(int, u_int32_t, void *);
236int	 channel_input_extended_data(int, u_int32_t, void *);
237int	 channel_input_ieof(int, u_int32_t, void *);
238int	 channel_input_oclose(int, u_int32_t, void *);
239int	 channel_input_open_confirmation(int, u_int32_t, void *);
240int	 channel_input_open_failure(int, u_int32_t, void *);
241int	 channel_input_port_open(int, u_int32_t, void *);
242int	 channel_input_window_adjust(int, u_int32_t, void *);
243int	 channel_input_status_confirm(int, u_int32_t, void *);
244
245/* file descriptor handling (read/write) */
246
247void	 channel_prepare_select(fd_set **, fd_set **, int *, u_int*,
248	     time_t*, int);
249void     channel_after_select(fd_set *, fd_set *);
250void     channel_output_poll(void);
251
252int      channel_not_very_much_buffered_data(void);
253void     channel_close_all(void);
254int      channel_still_open(void);
255char	*channel_open_message(void);
256int	 channel_find_open(void);
257
258/* tcp forwarding */
259struct Forward;
260struct ForwardOptions;
261void	 channel_set_af(int af);
262void     channel_permit_all_opens(void);
263void	 channel_add_permitted_opens(char *, int);
264int	 channel_add_adm_permitted_opens(char *, int);
265void	 channel_disable_adm_local_opens(void);
266void	 channel_update_permitted_opens(int, int);
267void	 channel_clear_permitted_opens(void);
268void	 channel_clear_adm_permitted_opens(void);
269void 	 channel_print_adm_permitted_opens(void);
270int      channel_input_port_forward_request(int, struct ForwardOptions *);
271Channel	*channel_connect_to_port(const char *, u_short, char *, char *);
272Channel *channel_connect_to_path(const char *, char *, char *);
273Channel	*channel_connect_stdio_fwd(const char*, u_short, int, int);
274Channel	*channel_connect_by_listen_address(const char *, u_short,
275	     char *, char *);
276Channel	*channel_connect_by_listen_path(const char *, char *, char *);
277int	 channel_request_remote_forwarding(struct Forward *);
278int	 channel_setup_local_fwd_listener(struct Forward *, struct ForwardOptions *);
279int	 channel_request_rforward_cancel(struct Forward *);
280int	 channel_setup_remote_fwd_listener(struct Forward *, int *, struct ForwardOptions *);
281int	 channel_cancel_rport_listener(struct Forward *);
282int	 channel_cancel_lport_listener(struct Forward *, int, struct ForwardOptions *);
283int	 permitopen_port(const char *);
284
285/* x11 forwarding */
286
287void	 channel_set_x11_refuse_time(u_int);
288int	 x11_connect_display(void);
289int	 x11_create_display_inet(int, int, int, u_int *, int **);
290int      x11_input_open(int, u_int32_t, void *);
291void	 x11_request_forwarding_with_spoofing(int, const char *, const char *,
292	     const char *, int);
293int	 deny_input_open(int, u_int32_t, void *);
294
295/* agent forwarding */
296
297void	 auth_request_forwarding(void);
298
299/* channel close */
300
301int	 chan_is_dead(Channel *, int);
302void	 chan_mark_dead(Channel *);
303
304/* channel events */
305
306void	 chan_rcvd_oclose(Channel *);
307void	 chan_rcvd_eow(Channel *);	/* SSH2-only */
308void	 chan_read_failed(Channel *);
309void	 chan_ibuf_empty(Channel *);
310
311void	 chan_rcvd_ieof(Channel *);
312void	 chan_write_failed(Channel *);
313void	 chan_obuf_empty(Channel *);
314
315#endif
316