• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /* $OpenBSD: channels.h,v 1.121 2017/02/01 02:59:09 dtucker 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_MUX_PROXY		20	/* proxy channel for mux-slave */
62 #define SSH_CHANNEL_MAX_TYPE		21
63 
64 #define CHANNEL_CANCEL_PORT_STATIC	-1
65 
66 struct Channel;
67 typedef struct Channel Channel;
68 
69 typedef void channel_open_fn(int, int, void *);
70 typedef void channel_callback_fn(int, void *);
71 typedef int channel_infilter_fn(struct Channel *, char *, int);
72 typedef void channel_filter_cleanup_fn(int, void *);
73 typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
74 
75 /* Channel success/failure callbacks */
76 typedef void channel_confirm_cb(int, struct Channel *, void *);
77 typedef void channel_confirm_abandon_cb(struct Channel *, void *);
78 struct channel_confirm {
79 	TAILQ_ENTRY(channel_confirm) entry;
80 	channel_confirm_cb *cb;
81 	channel_confirm_abandon_cb *abandon_cb;
82 	void *ctx;
83 };
84 TAILQ_HEAD(channel_confirms, channel_confirm);
85 
86 /* Context for non-blocking connects */
87 struct channel_connect {
88 	char *host;
89 	int port;
90 	struct addrinfo *ai, *aitop;
91 };
92 
93 /* Callbacks for mux channels back into client-specific code */
94 typedef int mux_callback_fn(struct Channel *);
95 
96 struct Channel {
97 	int     type;		/* channel type/state */
98 	int     self;		/* my own channel identifier */
99 	int     remote_id;	/* channel identifier for remote peer */
100 	u_int   istate;		/* input from channel (state of receive half) */
101 	u_int   ostate;		/* output to channel  (state of transmit half) */
102 	int     flags;		/* close sent/rcvd */
103 	int     rfd;		/* read fd */
104 	int     wfd;		/* write fd */
105 	int     efd;		/* extended fd */
106 	int     sock;		/* sock fd */
107 	int     ctl_chan;	/* control channel (multiplexed connections) */
108 	int     isatty;		/* rfd is a tty */
109 #ifdef _AIX
110 	int     wfd_isatty;	/* wfd is a tty */
111 #endif
112 	int	client_tty;	/* (client) TTY has been requested */
113 	int     force_drain;	/* force close on iEOF */
114 	time_t	notbefore;	/* Pause IO until deadline (time_t) */
115 	int     delayed;	/* post-select handlers for newly created
116 				 * channels are delayed until the first call
117 				 * to a matching pre-select handler.
118 				 * this way post-select handlers are not
119 				 * accidentally called if a FD gets reused */
120 	Buffer  input;		/* data read from socket, to be sent over
121 				 * encrypted connection */
122 	Buffer  output;		/* data received over encrypted connection for
123 				 * send on socket */
124 	Buffer  extended;
125 	char    *path;
126 		/* path for unix domain sockets, or host name for forwards */
127 	int     listening_port;	/* port being listened for forwards */
128 	char   *listening_addr;	/* addr being listened for forwards */
129 	int     host_port;	/* remote port to connect for forwards */
130 	char   *remote_name;	/* remote hostname */
131 
132 	u_int	remote_window;
133 	u_int	remote_maxpacket;
134 	u_int	local_window;
135 	u_int	local_window_max;
136 	u_int	local_consumed;
137 	u_int	local_maxpacket;
138 	int     extended_usage;
139 	int	single_connection;
140 
141 	char   *ctype;		/* type */
142 
143 	/* callback */
144 	channel_open_fn		*open_confirm;
145 	void			*open_confirm_ctx;
146 	channel_callback_fn	*detach_user;
147 	int			detach_close;
148 	struct channel_confirms	status_confirms;
149 
150 	/* filter */
151 	channel_infilter_fn	*input_filter;
152 	channel_outfilter_fn	*output_filter;
153 	void			*filter_ctx;
154 	channel_filter_cleanup_fn *filter_cleanup;
155 
156 	/* keep boundaries */
157 	int     		datagram;
158 
159 	/* non-blocking connect */
160 	struct channel_connect	connect_ctx;
161 
162 	/* multiplexing protocol hook, called for each packet received */
163 	mux_callback_fn		*mux_rcb;
164 	void			*mux_ctx;
165 	int			mux_pause;
166 	int     		mux_downstream_id;
167 };
168 
169 #define CHAN_EXTENDED_IGNORE		0
170 #define CHAN_EXTENDED_READ		1
171 #define CHAN_EXTENDED_WRITE		2
172 
173 /* default window/packet sizes for tcp/x11-fwd-channel */
174 #define CHAN_SES_PACKET_DEFAULT	(32*1024)
175 #define CHAN_SES_WINDOW_DEFAULT	(64*CHAN_SES_PACKET_DEFAULT)
176 #define CHAN_TCP_PACKET_DEFAULT	(32*1024)
177 #define CHAN_TCP_WINDOW_DEFAULT	(64*CHAN_TCP_PACKET_DEFAULT)
178 #define CHAN_X11_PACKET_DEFAULT	(16*1024)
179 #define CHAN_X11_WINDOW_DEFAULT	(4*CHAN_X11_PACKET_DEFAULT)
180 
181 /* possible input states */
182 #define CHAN_INPUT_OPEN			0
183 #define CHAN_INPUT_WAIT_DRAIN		1
184 #define CHAN_INPUT_WAIT_OCLOSE		2
185 #define CHAN_INPUT_CLOSED		3
186 
187 /* possible output states */
188 #define CHAN_OUTPUT_OPEN		0
189 #define CHAN_OUTPUT_WAIT_DRAIN		1
190 #define CHAN_OUTPUT_WAIT_IEOF		2
191 #define CHAN_OUTPUT_CLOSED		3
192 
193 #define CHAN_CLOSE_SENT			0x01
194 #define CHAN_CLOSE_RCVD			0x02
195 #define CHAN_EOF_SENT			0x04
196 #define CHAN_EOF_RCVD			0x08
197 #define CHAN_LOCAL			0x10
198 
199 #define CHAN_RBUF	16*1024
200 
201 /* check whether 'efd' is still in use */
202 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
203 	(compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
204 	(c->efd != -1 || \
205 	buffer_len(&c->extended) > 0))
206 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
207 	(compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
208 	c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
209 	buffer_len(&c->extended) > 0))
210 
211 /* channel management */
212 
213 Channel	*channel_by_id(int);
214 Channel	*channel_by_remote_id(int);
215 Channel	*channel_lookup(int);
216 Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
217 void	 channel_set_fds(int, int, int, int, int, int, int, u_int);
218 void	 channel_free(Channel *);
219 void	 channel_free_all(void);
220 void	 channel_stop_listening(void);
221 
222 void	 channel_send_open(int);
223 void	 channel_request_start(int, char *, int);
224 void	 channel_register_cleanup(int, channel_callback_fn *, int);
225 void	 channel_register_open_confirm(int, channel_open_fn *, void *);
226 void	 channel_register_filter(int, channel_infilter_fn *,
227     channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
228 void	 channel_register_status_confirm(int, channel_confirm_cb *,
229     channel_confirm_abandon_cb *, void *);
230 void	 channel_cancel_cleanup(int);
231 int	 channel_close_fd(int *);
232 void	 channel_send_window_changes(void);
233 
234 /* mux proxy support */
235 
236 int	 channel_proxy_downstream(Channel *mc);
237 int	 channel_proxy_upstream(Channel *, int, u_int32_t, void *);
238 
239 /* protocol handler */
240 
241 int	 channel_input_close(int, u_int32_t, void *);
242 int	 channel_input_close_confirmation(int, u_int32_t, void *);
243 int	 channel_input_data(int, u_int32_t, void *);
244 int	 channel_input_extended_data(int, u_int32_t, void *);
245 int	 channel_input_ieof(int, u_int32_t, void *);
246 int	 channel_input_oclose(int, u_int32_t, void *);
247 int	 channel_input_open_confirmation(int, u_int32_t, void *);
248 int	 channel_input_open_failure(int, u_int32_t, void *);
249 int	 channel_input_port_open(int, u_int32_t, void *);
250 int	 channel_input_window_adjust(int, u_int32_t, void *);
251 int	 channel_input_status_confirm(int, u_int32_t, void *);
252 
253 /* file descriptor handling (read/write) */
254 
255 void	 channel_prepare_select(fd_set **, fd_set **, int *, u_int*,
256 	     time_t*, int);
257 void     channel_after_select(fd_set *, fd_set *);
258 void     channel_output_poll(void);
259 
260 int      channel_not_very_much_buffered_data(void);
261 void     channel_close_all(void);
262 int      channel_still_open(void);
263 char	*channel_open_message(void);
264 int	 channel_find_open(void);
265 
266 /* tcp forwarding */
267 struct Forward;
268 struct ForwardOptions;
269 void	 channel_set_af(int af);
270 void     channel_permit_all_opens(void);
271 void	 channel_add_permitted_opens(char *, int);
272 int	 channel_add_adm_permitted_opens(char *, int);
273 void	 channel_disable_adm_local_opens(void);
274 void	 channel_update_permitted_opens(int, int);
275 void	 channel_clear_permitted_opens(void);
276 void	 channel_clear_adm_permitted_opens(void);
277 void 	 channel_print_adm_permitted_opens(void);
278 Channel	*channel_connect_to_port(const char *, u_short, char *, char *, int *,
279 	     const char **);
280 Channel *channel_connect_to_path(const char *, char *, char *);
281 Channel	*channel_connect_stdio_fwd(const char*, u_short, int, int);
282 Channel	*channel_connect_by_listen_address(const char *, u_short,
283 	     char *, char *);
284 Channel	*channel_connect_by_listen_path(const char *, char *, char *);
285 int	 channel_request_remote_forwarding(struct Forward *);
286 int	 channel_setup_local_fwd_listener(struct Forward *, struct ForwardOptions *);
287 int	 channel_request_rforward_cancel(struct Forward *);
288 int	 channel_setup_remote_fwd_listener(struct Forward *, int *, struct ForwardOptions *);
289 int	 channel_cancel_rport_listener(struct Forward *);
290 int	 channel_cancel_lport_listener(struct Forward *, int, struct ForwardOptions *);
291 int	 permitopen_port(const char *);
292 
293 /* x11 forwarding */
294 
295 void	 channel_set_x11_refuse_time(u_int);
296 int	 x11_connect_display(void);
297 int	 x11_create_display_inet(int, int, int, u_int *, int **);
298 int      x11_input_open(int, u_int32_t, void *);
299 void	 x11_request_forwarding_with_spoofing(int, const char *, const char *,
300 	     const char *, int);
301 int	 deny_input_open(int, u_int32_t, void *);
302 
303 /* agent forwarding */
304 
305 void	 auth_request_forwarding(void);
306 
307 /* channel close */
308 
309 int	 chan_is_dead(Channel *, int);
310 void	 chan_mark_dead(Channel *);
311 
312 /* channel events */
313 
314 void	 chan_rcvd_oclose(Channel *);
315 void	 chan_rcvd_eow(Channel *);	/* SSH2-only */
316 void	 chan_read_failed(Channel *);
317 void	 chan_ibuf_empty(Channel *);
318 
319 void	 chan_rcvd_ieof(Channel *);
320 void	 chan_write_failed(Channel *);
321 void	 chan_obuf_empty(Channel *);
322 
323 #endif
324