2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
13 * Copyright (c) 2000 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 /* RCSID("$OpenBSD: channels.h,v 1.33 2001/05/28 23:14:49 markus Exp $"); */
42 /* Definitions for channel types. */
43 #define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */
44 #define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */
45 #define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */
46 #define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */
47 #define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */
48 #define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */
49 #define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */
50 #define SSH_CHANNEL_INPUT_DRAINING 8 /* sending remaining data to conn */
51 #define SSH_CHANNEL_OUTPUT_DRAINING 9 /* sending remaining data to app */
52 #define SSH_CHANNEL_LARVAL 10 /* larval session */
53 #define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */
54 #define SSH_CHANNEL_CONNECTING 12
55 #define SSH_CHANNEL_DYNAMIC 13
56 #define SSH_CHANNEL_ZOMBIE 14 /* Almost dead. */
57 #define SSH_CHANNEL_MAX_TYPE 15
59 #define SSH_CHANNEL_PATH_LEN 30
62 * Data structure for channel data. This is initialized in channel_new
63 * and cleared in channel_free.
66 typedef struct Channel Channel;
68 typedef void channel_callback_fn(int id, void *arg);
69 typedef int channel_filter_fn(struct Channel *c, char *buf, int len);
72 int type; /* channel type/state */
73 int self; /* my own channel identifier */
74 int remote_id; /* channel identifier for remote peer */
75 /* peer can be reached over encrypted connection, via packet-sent */
76 int istate; /* input from channel (state of receive half) */
77 int ostate; /* output to channel (state of transmit half) */
78 int flags; /* close sent/rcvd */
79 int rfd; /* read fd */
80 int wfd; /* write fd */
81 int efd; /* extended fd */
82 int sock; /* sock fd */
83 int isatty; /* rfd is a tty */
84 Buffer input; /* data read from socket, to be sent over
85 * encrypted connection */
86 Buffer output; /* data received over encrypted connection for
89 char path[SSH_CHANNEL_PATH_LEN];
90 /* path for unix domain sockets, or host name for forwards */
91 int listening_port; /* port being listened for forwards */
92 int host_port; /* remote port to connect for forwards */
93 char *remote_name; /* remote hostname */
103 char *ctype; /* type */
106 channel_callback_fn *cb_fn;
109 channel_callback_fn *dettach_user;
112 channel_filter_fn *input_filter;
115 #define CHAN_EXTENDED_IGNORE 0
116 #define CHAN_EXTENDED_READ 1
117 #define CHAN_EXTENDED_WRITE 2
119 /* default window/packet sizes for tcp/x11-fwd-channel */
120 #define CHAN_SES_WINDOW_DEFAULT (32*1024)
121 #define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2)
122 #define CHAN_TCP_WINDOW_DEFAULT (32*1024)
123 #define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
124 #define CHAN_X11_WINDOW_DEFAULT (4*1024)
125 #define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)
128 void channel_open(int id);
129 void channel_request(int id, char *service, int wantconfirm);
130 void channel_request_start(int id, char *service, int wantconfirm);
131 void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
132 void channel_register_cleanup(int id, channel_callback_fn *fn);
133 void channel_register_filter(int id, channel_filter_fn *fn);
134 void channel_cancel_cleanup(int id);
135 Channel *channel_lookup(int id);
138 channel_set_fds(int id, int rfd, int wfd, int efd,
139 int extusage, int nonblock);
141 void deny_input_open(int type, int plen, void *ctxt);
143 void channel_input_channel_request(int type, int plen, void *ctxt);
144 void channel_input_close(int type, int plen, void *ctxt);
145 void channel_input_close_confirmation(int type, int plen, void *ctxt);
146 void channel_input_data(int type, int plen, void *ctxt);
147 void channel_input_extended_data(int type, int plen, void *ctxt);
148 void channel_input_ieof(int type, int plen, void *ctxt);
149 void channel_input_oclose(int type, int plen, void *ctxt);
150 void channel_input_open_confirmation(int type, int plen, void *ctxt);
151 void channel_input_open_failure(int type, int plen, void *ctxt);
152 void channel_input_port_open(int type, int plen, void *ctxt);
153 void channel_input_window_adjust(int type, int plen, void *ctxt);
155 /* Sets specific protocol options. */
156 void channel_set_options(int hostname_in_open);
159 * Allocate a new channel object and set its type and socket. Remote_name
160 * must have been allocated with xmalloc; this will free it when the channel
164 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
165 int window, int maxpack, int extended_usage, char *remote_name,
168 /* Free the channel and close its socket. */
169 void channel_free(Channel *c);
172 * Allocate/update select bitmasks and add any bits relevant to channels in
176 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
180 * After select, perform any appropriate operations for channels which have
183 void channel_after_select(fd_set * readset, fd_set * writeset);
185 /* If there is data to send to the connection, send some of it now. */
186 void channel_output_poll(void);
188 /* Returns true if no channel has too much buffered data. */
189 int channel_not_very_much_buffered_data(void);
191 /* This closes any sockets that are listening for connections; this removes
192 any unix domain sockets. */
193 void channel_stop_listening(void);
196 * Closes the sockets of all channels. This is used to close extra file
197 * descriptors after a fork.
199 void channel_close_all(void);
201 /* Returns true if there is still an open channel over the connection. */
202 int channel_still_open(void);
205 * Returns a string containing a list of all open channels. The list is
206 * suitable for displaying to the user. It uses crlf instead of newlines.
207 * The caller should free the string with xfree.
209 char *channel_open_message(void);
212 * Initiate forwarding of connections to local port "port" through the secure
213 * channel to host:port from remote side.
216 channel_request_local_forwarding(u_short listen_port,
217 const char *host_to_connect, u_short port_to_connect, int gateway_ports);
219 channel_request_forwarding(const char *listen_address, u_short listen_port,
220 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
224 * Initiate forwarding of connections to port "port" on remote host through
225 * the secure channel to host:port from local side. This never returns if
226 * there was an error. This registers that open requests for that port are
230 channel_request_remote_forwarding(u_short port, const char *host,
231 u_short remote_port);
234 * Permits opening to any host/port if permitted_opens[] is empty. This is
235 * usually called by the server, because the user could connect to any port
236 * anyway, and the server has no way to know but to trust the client anyway.
238 void channel_permit_all_opens(void);
240 /* Add host/port to list of allowed targets for port forwarding */
241 void channel_add_permitted_opens(char *host, int port);
244 void channel_clear_permitted_opens(void);
247 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
248 * listening for the port, and sends back a success reply (or disconnect
249 * message if there was an error). This never returns if there was an error.
251 void channel_input_port_forward_request(int is_root, int gateway_ports);
254 * Creates a port for X11 connections, and starts listening for it. Returns
255 * the display name, or NULL if an error was encountered.
257 char *x11_create_display(int screen);
260 * Creates an internet domain socket for listening for X11 connections.
261 * Returns a suitable value for the DISPLAY variable, or NULL if an error
264 char *x11_create_display_inet(int screen, int x11_display_offset);
267 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
268 * the remote channel number. We should do whatever we want, and respond
269 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
271 void x11_input_open(int type, int plen, void *ctxt);
274 * Requests forwarding of X11 connections. This should be called on the
277 void x11_request_forwarding(void);
280 * Requests forwarding for X11 connections, with authentication spoofing.
281 * This should be called in the client only.
284 x11_request_forwarding_with_spoofing(int client_session_id,
285 const char *proto, const char *data);
287 /* Sends a message to the server to request authentication fd forwarding. */
288 void auth_request_forwarding(void);
291 * Returns the name of the forwarded authentication socket. Returns NULL if
292 * there is no forwarded authentication socket. The returned value points to
295 char *auth_get_socket_name(void);
298 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
299 * This starts forwarding authentication requests.
301 int auth_input_request_forwarding(struct passwd * pw);
303 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
304 void auth_input_open_request(int type, int plen, void *ctxt);
307 int channel_connect_to(const char *host, u_short host_port);
308 int channel_connect_by_listen_adress(u_short listen_port);
309 int x11_connect_display(void);
311 int channel_find_open(void);