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 1.20 2000/09/21 11:25:33 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_MAX_TYPE 11
55 * Data structure for channel data. This is iniailized in channel_allocate
56 * and cleared in channel_free.
59 typedef struct Channel Channel;
61 typedef void channel_callback_fn(int id, void *arg);
62 typedef int channel_filter_fn(struct Channel *c, char *buf, int len);
65 int type; /* channel type/state */
66 int self; /* my own channel identifier */
67 int remote_id; /* channel identifier for remote peer */
68 /* peer can be reached over encrypted connection, via packet-sent */
69 int istate; /* input from channel (state of receive half) */
70 int ostate; /* output to channel (state of transmit half) */
71 int flags; /* close sent/rcvd */
72 int rfd; /* read fd */
73 int wfd; /* write fd */
74 int efd; /* extended fd */
75 int sock; /* sock fd */
76 Buffer input; /* data read from socket, to be sent over
77 * encrypted connection */
78 Buffer output; /* data received over encrypted connection for
81 char path[200]; /* path for unix domain sockets, or host name
83 int listening_port; /* port being listened for forwards */
84 int host_port; /* remote port to connect for forwards */
85 char *remote_name; /* remote hostname */
95 char *ctype; /* type */
98 channel_callback_fn *cb_fn;
101 channel_callback_fn *dettach_user;
104 channel_filter_fn *input_filter;
107 #define CHAN_EXTENDED_IGNORE 0
108 #define CHAN_EXTENDED_READ 1
109 #define CHAN_EXTENDED_WRITE 2
111 /* default window/packet sizes for tcp/x11-fwd-channel */
112 #define CHAN_SES_WINDOW_DEFAULT (32*1024)
113 #define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2)
114 #define CHAN_TCP_WINDOW_DEFAULT (32*1024)
115 #define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2)
116 #define CHAN_X11_WINDOW_DEFAULT (4*1024)
117 #define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2)
120 void channel_set_fds(int id, int rfd, int wfd, int efd, int extusage);
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);
134 void channel_input_channel_request(int type, int plen, void *ctxt);
135 void channel_input_close(int type, int plen, void *ctxt);
136 void channel_input_close_confirmation(int type, int plen, void *ctxt);
137 void channel_input_data(int type, int plen, void *ctxt);
138 void channel_input_extended_data(int type, int plen, void *ctxt);
139 void channel_input_ieof(int type, int plen, void *ctxt);
140 void channel_input_oclose(int type, int plen, void *ctxt);
141 void channel_input_open_confirmation(int type, int plen, void *ctxt);
142 void channel_input_open_failure(int type, int plen, void *ctxt);
143 void channel_input_port_open(int type, int plen, void *ctxt);
144 void channel_input_window_adjust(int type, int plen, void *ctxt);
145 void channel_input_open(int type, int plen, void *ctxt);
147 /* Sets specific protocol options. */
148 void channel_set_options(int hostname_in_open);
151 * Allocate a new channel object and set its type and socket. Remote_name
152 * must have been allocated with xmalloc; this will free it when the channel
155 int channel_allocate(int type, int sock, char *remote_name);
157 /* Free the channel and close its socket. */
158 void channel_free(int channel);
160 /* Add any bits relevant to channels in select bitmasks. */
161 void channel_prepare_select(fd_set * readset, fd_set * writeset);
164 * After select, perform any appropriate operations for channels which have
167 void channel_after_select(fd_set * readset, fd_set * writeset);
169 /* If there is data to send to the connection, send some of it now. */
170 void channel_output_poll(void);
172 /* Returns true if no channel has too much buffered data. */
173 int channel_not_very_much_buffered_data(void);
175 /* This closes any sockets that are listening for connections; this removes
176 any unix domain sockets. */
177 void channel_stop_listening(void);
180 * Closes the sockets of all channels. This is used to close extra file
181 * descriptors after a fork.
183 void channel_close_all(void);
185 /* Returns the maximum file descriptor number used by the channels. */
186 int channel_max_fd(void);
188 /* Returns true if there is still an open channel over the connection. */
189 int channel_still_open(void);
192 * Returns a string containing a list of all open channels. The list is
193 * suitable for displaying to the user. It uses crlf instead of newlines.
194 * The caller should free the string with xfree.
196 char *channel_open_message(void);
199 * Initiate forwarding of connections to local port "port" through the secure
200 * channel to host:port from remote side. This never returns if there was an
204 channel_request_local_forwarding(u_short port, const char *host,
205 u_short remote_port, int gateway_ports);
208 * Initiate forwarding of connections to port "port" on remote host through
209 * the secure channel to host:port from local side. This never returns if
210 * there was an error. This registers that open requests for that port are
214 channel_request_remote_forwarding(u_short port, const char *host,
215 u_short remote_port);
218 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
219 * called by the server, because the user could connect to any port anyway,
220 * and the server has no way to know but to trust the client anyway.
222 void channel_permit_all_opens(void);
225 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
226 * listening for the port, and sends back a success reply (or disconnect
227 * message if there was an error). This never returns if there was an error.
229 void channel_input_port_forward_request(int is_root, int gateway_ports);
232 * Creates a port for X11 connections, and starts listening for it. Returns
233 * the display name, or NULL if an error was encountered.
235 char *x11_create_display(int screen);
238 * Creates an internet domain socket for listening for X11 connections.
239 * Returns a suitable value for the DISPLAY variable, or NULL if an error
242 char *x11_create_display_inet(int screen, int x11_display_offset);
245 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
246 * the remote channel number. We should do whatever we want, and respond
247 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
249 void x11_input_open(int type, int plen, void *ctxt);
252 * Requests forwarding of X11 connections. This should be called on the
255 void x11_request_forwarding(void);
258 * Requests forwarding for X11 connections, with authentication spoofing.
259 * This should be called in the client only.
262 x11_request_forwarding_with_spoofing(int client_session_id,
263 const char *proto, const char *data);
265 /* Sends a message to the server to request authentication fd forwarding. */
266 void auth_request_forwarding(void);
269 * Returns the name of the forwarded authentication socket. Returns NULL if
270 * there is no forwarded authentication socket. The returned value points to
273 char *auth_get_socket_name(void);
276 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
277 * This starts forwarding authentication requests.
279 int auth_input_request_forwarding(struct passwd * pw);
281 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
282 void auth_input_open_request(int type, int plen, void *ctxt);
285 int channel_connect_to(const char *host, u_short host_port);
286 int x11_connect_display(void);