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 1.23 2000/11/06 23:04:56 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_MAX_TYPE 12
56 * Data structure for channel data. This is iniailized in channel_allocate
57 * and cleared in channel_free.
60 typedef struct Channel Channel;
62 typedef void channel_callback_fn(int id, void *arg);
63 typedef int channel_filter_fn(struct Channel *c, char *buf, int len);
66 int type; /* channel type/state */
67 int self; /* my own channel identifier */
68 int remote_id; /* channel identifier for remote peer */
69 /* peer can be reached over encrypted connection, via packet-sent */
70 int istate; /* input from channel (state of receive half) */
71 int ostate; /* output to channel (state of transmit half) */
72 int flags; /* close sent/rcvd */
73 int rfd; /* read fd */
74 int wfd; /* write fd */
75 int efd; /* extended fd */
76 int sock; /* sock fd */
77 Buffer input; /* data read from socket, to be sent over
78 * encrypted connection */
79 Buffer output; /* data received over encrypted connection for
82 char path[200]; /* path for unix domain sockets, or host name
84 int listening_port; /* port being listened for forwards */
85 int host_port; /* remote port to connect for forwards */
86 char *remote_name; /* remote hostname */
96 char *ctype; /* type */
99 channel_callback_fn *cb_fn;
102 channel_callback_fn *dettach_user;
105 channel_filter_fn *input_filter;
108 #define CHAN_EXTENDED_IGNORE 0
109 #define CHAN_EXTENDED_READ 1
110 #define CHAN_EXTENDED_WRITE 2
112 /* default window/packet sizes for tcp/x11-fwd-channel */
113 #define CHAN_SES_WINDOW_DEFAULT (32*1024)
114 #define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2)
115 #define CHAN_TCP_WINDOW_DEFAULT (32*1024)
116 #define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
117 #define CHAN_X11_WINDOW_DEFAULT (4*1024)
118 #define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)
121 void channel_open(int id);
122 void channel_request(int id, char *service, int wantconfirm);
123 void channel_request_start(int id, char *service, int wantconfirm);
124 void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
125 void channel_register_cleanup(int id, channel_callback_fn *fn);
126 void channel_register_filter(int id, channel_filter_fn *fn);
127 void channel_cancel_cleanup(int id);
128 Channel *channel_lookup(int id);
131 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
132 int window, int maxpack, int extended_usage, char *remote_name,
135 channel_set_fds(int id, int rfd, int wfd, int efd,
136 int extusage, int nonblock);
138 void deny_input_open(int type, int plen, void *ctxt);
140 void channel_input_channel_request(int type, int plen, void *ctxt);
141 void channel_input_close(int type, int plen, void *ctxt);
142 void channel_input_close_confirmation(int type, int plen, void *ctxt);
143 void channel_input_data(int type, int plen, void *ctxt);
144 void channel_input_extended_data(int type, int plen, void *ctxt);
145 void channel_input_ieof(int type, int plen, void *ctxt);
146 void channel_input_oclose(int type, int plen, void *ctxt);
147 void channel_input_open_confirmation(int type, int plen, void *ctxt);
148 void channel_input_open_failure(int type, int plen, void *ctxt);
149 void channel_input_port_open(int type, int plen, void *ctxt);
150 void channel_input_window_adjust(int type, int plen, void *ctxt);
152 /* Sets specific protocol options. */
153 void channel_set_options(int hostname_in_open);
156 * Allocate a new channel object and set its type and socket. Remote_name
157 * must have been allocated with xmalloc; this will free it when the channel
160 int channel_allocate(int type, int sock, char *remote_name);
162 /* Free the channel and close its socket. */
163 void channel_free(int channel);
165 /* Add any bits relevant to channels in select bitmasks. */
166 void channel_prepare_select(fd_set * readset, fd_set * writeset);
169 * After select, perform any appropriate operations for channels which have
172 void channel_after_select(fd_set * readset, fd_set * writeset);
174 /* If there is data to send to the connection, send some of it now. */
175 void channel_output_poll(void);
177 /* Returns true if no channel has too much buffered data. */
178 int channel_not_very_much_buffered_data(void);
180 /* This closes any sockets that are listening for connections; this removes
181 any unix domain sockets. */
182 void channel_stop_listening(void);
185 * Closes the sockets of all channels. This is used to close extra file
186 * descriptors after a fork.
188 void channel_close_all(void);
190 /* Returns the maximum file descriptor number used by the channels. */
191 int channel_max_fd(void);
193 /* Returns true if there is still an open channel over the connection. */
194 int channel_still_open(void);
197 * Returns a string containing a list of all open channels. The list is
198 * suitable for displaying to the user. It uses crlf instead of newlines.
199 * The caller should free the string with xfree.
201 char *channel_open_message(void);
204 * Initiate forwarding of connections to local port "port" through the secure
205 * channel to host:port from remote side.
208 channel_request_local_forwarding(u_short listen_port,
209 const char *host_to_connect, u_short port_to_connect, int gateway_ports);
211 channel_request_forwarding(const char *listen_address, u_short listen_port,
212 const char *host_to_connect, u_short port_to_connect, int gateway_ports,
216 * Initiate forwarding of connections to port "port" on remote host through
217 * the secure channel to host:port from local side. This never returns if
218 * there was an error. This registers that open requests for that port are
222 channel_request_remote_forwarding(u_short port, const char *host,
223 u_short remote_port);
226 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
227 * called by the server, because the user could connect to any port anyway,
228 * and the server has no way to know but to trust the client anyway.
230 void channel_permit_all_opens(void);
233 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
234 * listening for the port, and sends back a success reply (or disconnect
235 * message if there was an error). This never returns if there was an error.
237 void channel_input_port_forward_request(int is_root, int gateway_ports);
240 * Creates a port for X11 connections, and starts listening for it. Returns
241 * the display name, or NULL if an error was encountered.
243 char *x11_create_display(int screen);
246 * Creates an internet domain socket for listening for X11 connections.
247 * Returns a suitable value for the DISPLAY variable, or NULL if an error
250 char *x11_create_display_inet(int screen, int x11_display_offset);
253 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
254 * the remote channel number. We should do whatever we want, and respond
255 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
257 void x11_input_open(int type, int plen, void *ctxt);
260 * Requests forwarding of X11 connections. This should be called on the
263 void x11_request_forwarding(void);
266 * Requests forwarding for X11 connections, with authentication spoofing.
267 * This should be called in the client only.
270 x11_request_forwarding_with_spoofing(int client_session_id,
271 const char *proto, const char *data);
273 /* Sends a message to the server to request authentication fd forwarding. */
274 void auth_request_forwarding(void);
277 * Returns the name of the forwarded authentication socket. Returns NULL if
278 * there is no forwarded authentication socket. The returned value points to
281 char *auth_get_socket_name(void);
284 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
285 * This starts forwarding authentication requests.
287 int auth_input_request_forwarding(struct passwd * pw);
289 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
290 void auth_input_open_request(int type, int plen, void *ctxt);
293 int channel_connect_to(const char *host, u_short host_port);
294 int channel_connect_by_listen_adress(u_short listen_port);
295 int x11_connect_display(void);