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 1.24 2000/12/05 20:34:10 markus Exp $"); */
40 /* Definitions for channel types. */
41 #define SSH_CHANNEL_FREE 0 /* This channel is free (unused). */
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_MAX_TYPE 13
57 * Data structure for channel data. This is iniailized in channel_allocate
58 * and cleared in channel_free.
61 typedef struct Channel Channel;
63 typedef void channel_callback_fn(int id, void *arg);
64 typedef int channel_filter_fn(struct Channel *c, char *buf, int len);
67 int type; /* channel type/state */
68 int self; /* my own channel identifier */
69 int remote_id; /* channel identifier for remote peer */
70 /* peer can be reached over encrypted connection, via packet-sent */
71 int istate; /* input from channel (state of receive half) */
72 int ostate; /* output to channel (state of transmit half) */
73 int flags; /* close sent/rcvd */
74 int rfd; /* read fd */
75 int wfd; /* write fd */
76 int efd; /* extended fd */
77 int sock; /* sock fd */
78 Buffer input; /* data read from socket, to be sent over
79 * encrypted connection */
80 Buffer output; /* data received over encrypted connection for
83 char path[200]; /* path for unix domain sockets, or host name
85 int listening_port; /* port being listened for forwards */
86 int host_port; /* remote port to connect for forwards */
87 char *remote_name; /* remote hostname */
97 char *ctype; /* type */
100 channel_callback_fn *cb_fn;
103 channel_callback_fn *dettach_user;
106 channel_filter_fn *input_filter;
109 #define CHAN_EXTENDED_IGNORE 0
110 #define CHAN_EXTENDED_READ 1
111 #define CHAN_EXTENDED_WRITE 2
113 /* default window/packet sizes for tcp/x11-fwd-channel */
114 #define CHAN_SES_WINDOW_DEFAULT (32*1024)
115 #define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2)
116 #define CHAN_TCP_WINDOW_DEFAULT (32*1024)
117 #define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
118 #define CHAN_X11_WINDOW_DEFAULT (4*1024)
119 #define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)
122 void channel_open(int id);
123 void channel_request(int id, char *service, int wantconfirm);
124 void channel_request_start(int id, char *service, int wantconfirm);
125 void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
126 void channel_register_cleanup(int id, channel_callback_fn *fn);
127 void channel_register_filter(int id, channel_filter_fn *fn);
128 void channel_cancel_cleanup(int id);
129 Channel *channel_lookup(int id);
132 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
133 int window, int maxpack, int extended_usage, char *remote_name,
136 channel_set_fds(int id, int rfd, int wfd, int efd,
137 int extusage, int nonblock);
139 void deny_input_open(int type, int plen, void *ctxt);
141 void channel_input_channel_request(int type, int plen, void *ctxt);
142 void channel_input_close(int type, int plen, void *ctxt);
143 void channel_input_close_confirmation(int type, int plen, void *ctxt);
144 void channel_input_data(int type, int plen, void *ctxt);
145 void channel_input_extended_data(int type, int plen, void *ctxt);
146 void channel_input_ieof(int type, int plen, void *ctxt);
147 void channel_input_oclose(int type, int plen, void *ctxt);
148 void channel_input_open_confirmation(int type, int plen, void *ctxt);
149 void channel_input_open_failure(int type, int plen, void *ctxt);
150 void channel_input_port_open(int type, int plen, void *ctxt);
151 void channel_input_window_adjust(int type, int plen, void *ctxt);
153 /* Sets specific protocol options. */
154 void channel_set_options(int hostname_in_open);
157 * Allocate a new channel object and set its type and socket. Remote_name
158 * must have been allocated with xmalloc; this will free it when the channel
161 int channel_allocate(int type, int sock, char *remote_name);
163 /* Free the channel and close its socket. */
164 void channel_free(int channel);
166 /* Add any bits relevant to channels in select bitmasks. */
167 void channel_prepare_select(fd_set * readset, fd_set * writeset);
170 * After select, perform any appropriate operations for channels which have
173 void channel_after_select(fd_set * readset, fd_set * writeset);
175 /* If there is data to send to the connection, send some of it now. */
176 void channel_output_poll(void);
178 /* Returns true if no channel has too much buffered data. */
179 int channel_not_very_much_buffered_data(void);
181 /* This closes any sockets that are listening for connections; this removes
182 any unix domain sockets. */
183 void channel_stop_listening(void);
186 * Closes the sockets of all channels. This is used to close extra file
187 * descriptors after a fork.
189 void channel_close_all(void);
191 /* Returns the maximum file descriptor number used by the channels. */
192 int channel_max_fd(void);
194 /* Returns true if there is still an open channel over the connection. */
195 int channel_still_open(void);
198 * Returns a string containing a list of all open channels. The list is
199 * suitable for displaying to the user. It uses crlf instead of newlines.
200 * The caller should free the string with xfree.
202 char *channel_open_message(void);
205 * Initiate forwarding of connections to local port "port" through the secure
206 * channel to host:port from remote side.
209 channel_request_local_forwarding(u_short listen_port,
210 const char *host_to_connect, u_short port_to_connect, int gateway_ports);
212 channel_request_forwarding(const char *listen_address, u_short listen_port,
213 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
217 * Initiate forwarding of connections to port "port" on remote host through
218 * the secure channel to host:port from local side. This never returns if
219 * there was an error. This registers that open requests for that port are
223 channel_request_remote_forwarding(u_short port, const char *host,
224 u_short remote_port);
227 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
228 * called by the server, because the user could connect to any port anyway,
229 * and the server has no way to know but to trust the client anyway.
231 void channel_permit_all_opens(void);
234 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
235 * listening for the port, and sends back a success reply (or disconnect
236 * message if there was an error). This never returns if there was an error.
238 void channel_input_port_forward_request(int is_root, int gateway_ports);
241 * Creates a port for X11 connections, and starts listening for it. Returns
242 * the display name, or NULL if an error was encountered.
244 char *x11_create_display(int screen);
247 * Creates an internet domain socket for listening for X11 connections.
248 * Returns a suitable value for the DISPLAY variable, or NULL if an error
251 char *x11_create_display_inet(int screen, int x11_display_offset);
254 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
255 * the remote channel number. We should do whatever we want, and respond
256 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
258 void x11_input_open(int type, int plen, void *ctxt);
261 * Requests forwarding of X11 connections. This should be called on the
264 void x11_request_forwarding(void);
267 * Requests forwarding for X11 connections, with authentication spoofing.
268 * This should be called in the client only.
271 x11_request_forwarding_with_spoofing(int client_session_id,
272 const char *proto, const char *data);
274 /* Sends a message to the server to request authentication fd forwarding. */
275 void auth_request_forwarding(void);
278 * Returns the name of the forwarded authentication socket. Returns NULL if
279 * there is no forwarded authentication socket. The returned value points to
282 char *auth_get_socket_name(void);
285 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
286 * This starts forwarding authentication requests.
288 int auth_input_request_forwarding(struct passwd * pw);
290 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
291 void auth_input_open_request(int type, int plen, void *ctxt);
294 int channel_connect_to(const char *host, u_short host_port);
295 int channel_connect_by_listen_adress(u_short listen_port);
296 int x11_connect_display(void);