1 /* $OpenBSD: channels.h,v 1.132 2018/10/04 00:10:11 djm Exp $ */
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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".
15 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
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.
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.
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_LARVAL 10 /* larval session */
50 #define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */
51 #define SSH_CHANNEL_CONNECTING 12
52 #define SSH_CHANNEL_DYNAMIC 13
53 #define SSH_CHANNEL_ZOMBIE 14 /* Almost dead. */
54 #define SSH_CHANNEL_MUX_LISTENER 15 /* Listener for mux conn. */
55 #define SSH_CHANNEL_MUX_CLIENT 16 /* Conn. to mux slave */
56 #define SSH_CHANNEL_ABANDONED 17 /* Abandoned session, eg mux */
57 #define SSH_CHANNEL_UNIX_LISTENER 18 /* Listening on a domain socket. */
58 #define SSH_CHANNEL_RUNIX_LISTENER 19 /* Listening to a R-style domain socket. */
59 #define SSH_CHANNEL_MUX_PROXY 20 /* proxy channel for mux-slave */
60 #define SSH_CHANNEL_RDYNAMIC_OPEN 21 /* reverse SOCKS, parsing request */
61 #define SSH_CHANNEL_RDYNAMIC_FINISH 22 /* reverse SOCKS, finishing connect */
62 #define SSH_CHANNEL_MAX_TYPE 23
64 #define CHANNEL_CANCEL_PORT_STATIC -1
67 #define FORWARD_DENY 0
68 #define FORWARD_REMOTE (1)
69 #define FORWARD_LOCAL (1<<1)
70 #define FORWARD_ALLOW (FORWARD_REMOTE|FORWARD_LOCAL)
72 #define FORWARD_ADM 0x100
73 #define FORWARD_USER 0x101
77 typedef struct Channel Channel;
80 typedef void channel_open_fn(struct ssh *, int, int, void *);
81 typedef void channel_callback_fn(struct ssh *, int, void *);
82 typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int);
83 typedef void channel_filter_cleanup_fn(struct ssh *, int, void *);
84 typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *,
87 /* Channel success/failure callbacks */
88 typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *);
89 typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *);
90 struct channel_confirm {
91 TAILQ_ENTRY(channel_confirm) entry;
92 channel_confirm_cb *cb;
93 channel_confirm_abandon_cb *abandon_cb;
96 TAILQ_HEAD(channel_confirms, channel_confirm);
98 /* Context for non-blocking connects */
99 struct channel_connect {
102 struct addrinfo *ai, *aitop;
105 /* Callbacks for mux channels back into client-specific code */
106 typedef int mux_callback_fn(struct ssh *, struct Channel *);
109 int type; /* channel type/state */
110 int self; /* my own channel identifier */
111 uint32_t remote_id; /* channel identifier for remote peer */
112 int have_remote_id; /* non-zero if remote_id is valid */
114 u_int istate; /* input from channel (state of receive half) */
115 u_int ostate; /* output to channel (state of transmit half) */
116 int flags; /* close sent/rcvd */
117 int rfd; /* read fd */
118 int wfd; /* write fd */
119 int efd; /* extended fd */
120 int sock; /* sock fd */
121 int ctl_chan; /* control channel (multiplexed connections) */
122 int isatty; /* rfd is a tty */
124 int wfd_isatty; /* wfd is a tty */
126 int client_tty; /* (client) TTY has been requested */
127 int force_drain; /* force close on iEOF */
128 time_t notbefore; /* Pause IO until deadline (time_t) */
129 int delayed; /* post-select handlers for newly created
130 * channels are delayed until the first call
131 * to a matching pre-select handler.
132 * this way post-select handlers are not
133 * accidentally called if a FD gets reused */
134 struct sshbuf *input; /* data read from socket, to be sent over
135 * encrypted connection */
136 struct sshbuf *output; /* data received over encrypted connection for
138 struct sshbuf *extended;
141 /* path for unix domain sockets, or host name for forwards */
142 int listening_port; /* port being listened for forwards */
143 char *listening_addr; /* addr being listened for forwards */
144 int host_port; /* remote port to connect for forwards */
145 char *remote_name; /* remote hostname */
148 u_int remote_maxpacket;
150 u_int local_window_max;
151 u_int local_consumed;
152 u_int local_maxpacket;
154 int single_connection;
156 char *ctype; /* type */
159 channel_open_fn *open_confirm;
160 void *open_confirm_ctx;
161 channel_callback_fn *detach_user;
163 struct channel_confirms status_confirms;
166 channel_infilter_fn *input_filter;
167 channel_outfilter_fn *output_filter;
169 channel_filter_cleanup_fn *filter_cleanup;
171 /* keep boundaries */
174 /* non-blocking connect */
175 /* XXX make this a pointer so the structure can be opaque */
176 struct channel_connect connect_ctx;
178 /* multiplexing protocol hook, called for each packet received */
179 mux_callback_fn *mux_rcb;
182 int mux_downstream_id;
185 #define CHAN_EXTENDED_IGNORE 0
186 #define CHAN_EXTENDED_READ 1
187 #define CHAN_EXTENDED_WRITE 2
189 /* default window/packet sizes for tcp/x11-fwd-channel */
190 #define CHAN_SES_PACKET_DEFAULT (32*1024)
191 #define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
192 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
193 #define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
194 #define CHAN_X11_PACKET_DEFAULT (16*1024)
195 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
197 /* possible input states */
198 #define CHAN_INPUT_OPEN 0
199 #define CHAN_INPUT_WAIT_DRAIN 1
200 #define CHAN_INPUT_WAIT_OCLOSE 2
201 #define CHAN_INPUT_CLOSED 3
203 /* possible output states */
204 #define CHAN_OUTPUT_OPEN 0
205 #define CHAN_OUTPUT_WAIT_DRAIN 1
206 #define CHAN_OUTPUT_WAIT_IEOF 2
207 #define CHAN_OUTPUT_CLOSED 3
209 #define CHAN_CLOSE_SENT 0x01
210 #define CHAN_CLOSE_RCVD 0x02
211 #define CHAN_EOF_SENT 0x04
212 #define CHAN_EOF_RCVD 0x08
213 #define CHAN_LOCAL 0x10
215 /* Read buffer size */
216 #define CHAN_RBUF (16*1024)
218 /* Hard limit on number of channels */
219 #define CHANNELS_MAX_CHANNELS (16*1024)
221 /* check whether 'efd' is still in use */
222 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
223 (c->extended_usage == CHAN_EXTENDED_READ && \
225 sshbuf_len(c->extended) > 0))
226 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
227 (c->extended_usage == CHAN_EXTENDED_WRITE && \
228 c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
229 sshbuf_len(c->extended) > 0))
231 /* Add channel management structures to SSH transport instance */
232 void channel_init_channels(struct ssh *ssh);
234 /* channel management */
236 Channel *channel_by_id(struct ssh *, int);
237 Channel *channel_by_remote_id(struct ssh *, u_int);
238 Channel *channel_lookup(struct ssh *, int);
239 Channel *channel_new(struct ssh *, char *, int, int, int, int,
240 u_int, u_int, int, char *, int);
241 void channel_set_fds(struct ssh *, int, int, int, int, int,
243 void channel_free(struct ssh *, Channel *);
244 void channel_free_all(struct ssh *);
245 void channel_stop_listening(struct ssh *);
247 void channel_send_open(struct ssh *, int);
248 void channel_request_start(struct ssh *, int, char *, int);
249 void channel_register_cleanup(struct ssh *, int,
250 channel_callback_fn *, int);
251 void channel_register_open_confirm(struct ssh *, int,
252 channel_open_fn *, void *);
253 void channel_register_filter(struct ssh *, int, channel_infilter_fn *,
254 channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
255 void channel_register_status_confirm(struct ssh *, int,
256 channel_confirm_cb *, channel_confirm_abandon_cb *, void *);
257 void channel_cancel_cleanup(struct ssh *, int);
258 int channel_close_fd(struct ssh *, int *);
259 void channel_send_window_changes(struct ssh *);
261 /* mux proxy support */
263 int channel_proxy_downstream(struct ssh *, Channel *mc);
264 int channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *);
266 /* protocol handler */
268 int channel_input_data(int, u_int32_t, struct ssh *);
269 int channel_input_extended_data(int, u_int32_t, struct ssh *);
270 int channel_input_ieof(int, u_int32_t, struct ssh *);
271 int channel_input_oclose(int, u_int32_t, struct ssh *);
272 int channel_input_open_confirmation(int, u_int32_t, struct ssh *);
273 int channel_input_open_failure(int, u_int32_t, struct ssh *);
274 int channel_input_port_open(int, u_int32_t, struct ssh *);
275 int channel_input_window_adjust(int, u_int32_t, struct ssh *);
276 int channel_input_status_confirm(int, u_int32_t, struct ssh *);
278 /* file descriptor handling (read/write) */
280 void channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *,
282 void channel_after_select(struct ssh *, fd_set *, fd_set *);
283 void channel_output_poll(struct ssh *);
285 int channel_not_very_much_buffered_data(struct ssh *);
286 void channel_close_all(struct ssh *);
287 int channel_still_open(struct ssh *);
288 const char *channel_format_extended_usage(const Channel *);
289 char *channel_open_message(struct ssh *);
290 int channel_find_open(struct ssh *);
294 struct ForwardOptions;
295 void channel_set_af(struct ssh *, int af);
296 void channel_permit_all(struct ssh *, int);
297 void channel_add_permission(struct ssh *, int, int, char *, int);
298 void channel_clear_permission(struct ssh *, int, int);
299 void channel_disable_admin(struct ssh *, int);
300 void channel_update_permission(struct ssh *, int, int);
301 Channel *channel_connect_to_port(struct ssh *, const char *, u_short,
302 char *, char *, int *, const char **);
303 Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *);
304 Channel *channel_connect_stdio_fwd(struct ssh *, const char*,
306 Channel *channel_connect_by_listen_address(struct ssh *, const char *,
307 u_short, char *, char *);
308 Channel *channel_connect_by_listen_path(struct ssh *, const char *,
310 int channel_request_remote_forwarding(struct ssh *, struct Forward *);
311 int channel_setup_local_fwd_listener(struct ssh *, struct Forward *,
312 struct ForwardOptions *);
313 int channel_request_rforward_cancel(struct ssh *, struct Forward *);
314 int channel_setup_remote_fwd_listener(struct ssh *, struct Forward *,
315 int *, struct ForwardOptions *);
316 int channel_cancel_rport_listener(struct ssh *, struct Forward *);
317 int channel_cancel_lport_listener(struct ssh *, struct Forward *,
318 int, struct ForwardOptions *);
319 int permitopen_port(const char *);
323 void channel_set_x11_refuse_time(struct ssh *, u_int);
324 int x11_connect_display(struct ssh *);
325 int x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **);
326 void x11_request_forwarding_with_spoofing(struct ssh *, int,
327 const char *, const char *, const char *, int);
331 int chan_is_dead(struct ssh *, Channel *, int);
332 void chan_mark_dead(struct ssh *, Channel *);
336 void chan_rcvd_oclose(struct ssh *, Channel *);
337 void chan_rcvd_eow(struct ssh *, Channel *);
338 void chan_read_failed(struct ssh *, Channel *);
339 void chan_ibuf_empty(struct ssh *, Channel *);
340 void chan_rcvd_ieof(struct ssh *, Channel *);
341 void chan_write_failed(struct ssh *, Channel *);
342 void chan_obuf_empty(struct ssh *, Channel *);