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1 | /* | |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * | |
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". | |
11 | */ | |
12 | /* | |
13 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
14 | * | |
15 | * Redistribution and use in source and binary forms, with or without | |
16 | * modification, are permitted provided that the following conditions | |
17 | * are met: | |
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. | |
23 | * | |
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. | |
34 | */ | |
35 | /* RCSID("$OpenBSD: channels.h,v 1.29 2001/04/04 20:25:36 markus Exp $"); */ | |
36 | ||
37 | #ifndef CHANNELS_H | |
38 | #define CHANNELS_H | |
39 | ||
40 | #include "buffer.h" | |
41 | ||
42 | /* Definitions for channel types. */ | |
43 | #define SSH_CHANNEL_FREE 0 /* This channel is free (unused). */ | |
44 | #define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */ | |
45 | #define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */ | |
46 | #define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */ | |
47 | #define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */ | |
48 | #define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */ | |
49 | #define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */ | |
50 | #define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */ | |
51 | #define SSH_CHANNEL_INPUT_DRAINING 8 /* sending remaining data to conn */ | |
52 | #define SSH_CHANNEL_OUTPUT_DRAINING 9 /* sending remaining data to app */ | |
53 | #define SSH_CHANNEL_LARVAL 10 /* larval session */ | |
54 | #define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */ | |
55 | #define SSH_CHANNEL_CONNECTING 12 | |
56 | #define SSH_CHANNEL_MAX_TYPE 13 | |
57 | ||
58 | /* | |
59 | * Data structure for channel data. This is iniailized in channel_allocate | |
60 | * and cleared in channel_free. | |
61 | */ | |
62 | struct Channel; | |
63 | typedef struct Channel Channel; | |
64 | ||
65 | typedef void channel_callback_fn(int id, void *arg); | |
66 | typedef int channel_filter_fn(struct Channel *c, char *buf, int len); | |
67 | ||
68 | struct Channel { | |
69 | int type; /* channel type/state */ | |
70 | int self; /* my own channel identifier */ | |
71 | int remote_id; /* channel identifier for remote peer */ | |
72 | /* peer can be reached over encrypted connection, via packet-sent */ | |
73 | int istate; /* input from channel (state of receive half) */ | |
74 | int ostate; /* output to channel (state of transmit half) */ | |
75 | int flags; /* close sent/rcvd */ | |
76 | int rfd; /* read fd */ | |
77 | int wfd; /* write fd */ | |
78 | int efd; /* extended fd */ | |
79 | int sock; /* sock fd */ | |
80 | int isatty; /* rfd is a tty */ | |
81 | Buffer input; /* data read from socket, to be sent over | |
82 | * encrypted connection */ | |
83 | Buffer output; /* data received over encrypted connection for | |
84 | * send on socket */ | |
85 | Buffer extended; | |
86 | char path[200]; /* path for unix domain sockets, or host name | |
87 | * for forwards */ | |
88 | int listening_port; /* port being listened for forwards */ | |
89 | int host_port; /* remote port to connect for forwards */ | |
90 | char *remote_name; /* remote hostname */ | |
91 | ||
92 | int remote_window; | |
93 | int remote_maxpacket; | |
94 | int local_window; | |
95 | int local_window_max; | |
96 | int local_consumed; | |
97 | int local_maxpacket; | |
98 | int extended_usage; | |
99 | ||
100 | char *ctype; /* type */ | |
101 | ||
102 | /* callback */ | |
103 | channel_callback_fn *cb_fn; | |
104 | void *cb_arg; | |
105 | int cb_event; | |
106 | channel_callback_fn *dettach_user; | |
107 | ||
108 | /* filter */ | |
109 | channel_filter_fn *input_filter; | |
110 | }; | |
111 | ||
112 | #define CHAN_EXTENDED_IGNORE 0 | |
113 | #define CHAN_EXTENDED_READ 1 | |
114 | #define CHAN_EXTENDED_WRITE 2 | |
115 | ||
116 | /* default window/packet sizes for tcp/x11-fwd-channel */ | |
117 | #define CHAN_SES_WINDOW_DEFAULT (32*1024) | |
118 | #define CHAN_SES_PACKET_DEFAULT (CHAN_SES_WINDOW_DEFAULT/2) | |
119 | #define CHAN_TCP_WINDOW_DEFAULT (32*1024) | |
120 | #define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2) | |
121 | #define CHAN_X11_WINDOW_DEFAULT (4*1024) | |
122 | #define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2) | |
123 | ||
124 | ||
125 | void channel_open(int id); | |
126 | void channel_request(int id, char *service, int wantconfirm); | |
127 | void channel_request_start(int id, char *service, int wantconfirm); | |
128 | void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg); | |
129 | void channel_register_cleanup(int id, channel_callback_fn *fn); | |
130 | void channel_register_filter(int id, channel_filter_fn *fn); | |
131 | void channel_cancel_cleanup(int id); | |
132 | Channel *channel_lookup(int id); | |
133 | ||
134 | int | |
135 | channel_new(char *ctype, int type, int rfd, int wfd, int efd, | |
136 | int window, int maxpack, int extended_usage, char *remote_name, | |
137 | int nonblock); | |
138 | void | |
139 | channel_set_fds(int id, int rfd, int wfd, int efd, | |
140 | int extusage, int nonblock); | |
141 | ||
142 | void deny_input_open(int type, int plen, void *ctxt); | |
143 | ||
144 | void channel_input_channel_request(int type, int plen, void *ctxt); | |
145 | void channel_input_close(int type, int plen, void *ctxt); | |
146 | void channel_input_close_confirmation(int type, int plen, void *ctxt); | |
147 | void channel_input_data(int type, int plen, void *ctxt); | |
148 | void channel_input_extended_data(int type, int plen, void *ctxt); | |
149 | void channel_input_ieof(int type, int plen, void *ctxt); | |
150 | void channel_input_oclose(int type, int plen, void *ctxt); | |
151 | void channel_input_open_confirmation(int type, int plen, void *ctxt); | |
152 | void channel_input_open_failure(int type, int plen, void *ctxt); | |
153 | void channel_input_port_open(int type, int plen, void *ctxt); | |
154 | void channel_input_window_adjust(int type, int plen, void *ctxt); | |
155 | ||
156 | /* Sets specific protocol options. */ | |
157 | void channel_set_options(int hostname_in_open); | |
158 | ||
159 | /* | |
160 | * Allocate a new channel object and set its type and socket. Remote_name | |
161 | * must have been allocated with xmalloc; this will free it when the channel | |
162 | * is freed. | |
163 | */ | |
164 | int channel_allocate(int type, int sock, char *remote_name); | |
165 | ||
166 | /* Free the channel and close its socket. */ | |
167 | void channel_free(int channel); | |
168 | ||
169 | /* | |
170 | * Allocate/update select bitmasks and add any bits relevant to channels in | |
171 | * select bitmasks. | |
172 | */ | |
173 | void | |
174 | channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, | |
175 | int rekeying); | |
176 | ||
177 | /* | |
178 | * After select, perform any appropriate operations for channels which have | |
179 | * events pending. | |
180 | */ | |
181 | void channel_after_select(fd_set * readset, fd_set * writeset); | |
182 | ||
183 | /* If there is data to send to the connection, send some of it now. */ | |
184 | void channel_output_poll(void); | |
185 | ||
186 | /* Returns true if no channel has too much buffered data. */ | |
187 | int channel_not_very_much_buffered_data(void); | |
188 | ||
189 | /* This closes any sockets that are listening for connections; this removes | |
190 | any unix domain sockets. */ | |
191 | void channel_stop_listening(void); | |
192 | ||
193 | /* | |
194 | * Closes the sockets of all channels. This is used to close extra file | |
195 | * descriptors after a fork. | |
196 | */ | |
197 | void channel_close_all(void); | |
198 | ||
199 | /* Returns true if there is still an open channel over the connection. */ | |
200 | int channel_still_open(void); | |
201 | ||
202 | /* | |
203 | * Returns a string containing a list of all open channels. The list is | |
204 | * suitable for displaying to the user. It uses crlf instead of newlines. | |
205 | * The caller should free the string with xfree. | |
206 | */ | |
207 | char *channel_open_message(void); | |
208 | ||
209 | /* | |
210 | * Initiate forwarding of connections to local port "port" through the secure | |
211 | * channel to host:port from remote side. | |
212 | */ | |
213 | int | |
214 | channel_request_local_forwarding(u_short listen_port, | |
215 | const char *host_to_connect, u_short port_to_connect, int gateway_ports); | |
216 | int | |
217 | channel_request_forwarding(const char *listen_address, u_short listen_port, | |
218 | const char *host_to_connect, u_short port_to_connect, int gateway_ports, | |
219 | int remote_fwd); | |
220 | ||
221 | /* | |
222 | * Initiate forwarding of connections to port "port" on remote host through | |
223 | * the secure channel to host:port from local side. This never returns if | |
224 | * there was an error. This registers that open requests for that port are | |
225 | * permitted. | |
226 | */ | |
227 | void | |
228 | channel_request_remote_forwarding(u_short port, const char *host, | |
229 | u_short remote_port); | |
230 | ||
231 | /* | |
232 | * Permits opening to any host/port if permitted_opens[] is empty. This is | |
233 | * usually called by the server, because the user could connect to any port | |
234 | * anyway, and the server has no way to know but to trust the client anyway. | |
235 | */ | |
236 | void channel_permit_all_opens(void); | |
237 | ||
238 | /* Add host/port to list of allowed targets for port forwarding */ | |
239 | void channel_add_permitted_opens(char *host, int port); | |
240 | ||
241 | /* Flush list */ | |
242 | void channel_clear_permitted_opens(void); | |
243 | ||
244 | /* | |
245 | * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates | |
246 | * listening for the port, and sends back a success reply (or disconnect | |
247 | * message if there was an error). This never returns if there was an error. | |
248 | */ | |
249 | void channel_input_port_forward_request(int is_root, int gateway_ports); | |
250 | ||
251 | /* | |
252 | * Creates a port for X11 connections, and starts listening for it. Returns | |
253 | * the display name, or NULL if an error was encountered. | |
254 | */ | |
255 | char *x11_create_display(int screen); | |
256 | ||
257 | /* | |
258 | * Creates an internet domain socket for listening for X11 connections. | |
259 | * Returns a suitable value for the DISPLAY variable, or NULL if an error | |
260 | * occurs. | |
261 | */ | |
262 | char *x11_create_display_inet(int screen, int x11_display_offset); | |
263 | ||
264 | /* | |
265 | * This is called when SSH_SMSG_X11_OPEN is received. The packet contains | |
266 | * the remote channel number. We should do whatever we want, and respond | |
267 | * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. | |
268 | */ | |
269 | void x11_input_open(int type, int plen, void *ctxt); | |
270 | ||
271 | /* | |
272 | * Requests forwarding of X11 connections. This should be called on the | |
273 | * client only. | |
274 | */ | |
275 | void x11_request_forwarding(void); | |
276 | ||
277 | /* | |
278 | * Requests forwarding for X11 connections, with authentication spoofing. | |
279 | * This should be called in the client only. | |
280 | */ | |
281 | void | |
282 | x11_request_forwarding_with_spoofing(int client_session_id, | |
283 | const char *proto, const char *data); | |
284 | ||
285 | /* Sends a message to the server to request authentication fd forwarding. */ | |
286 | void auth_request_forwarding(void); | |
287 | ||
288 | /* | |
289 | * Returns the name of the forwarded authentication socket. Returns NULL if | |
290 | * there is no forwarded authentication socket. The returned value points to | |
291 | * a static buffer. | |
292 | */ | |
293 | char *auth_get_socket_name(void); | |
294 | ||
295 | /* | |
296 | * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. | |
297 | * This starts forwarding authentication requests. | |
298 | */ | |
299 | int auth_input_request_forwarding(struct passwd * pw); | |
300 | ||
301 | /* This is called to process an SSH_SMSG_AGENT_OPEN message. */ | |
302 | void auth_input_open_request(int type, int plen, void *ctxt); | |
303 | ||
304 | /* XXX */ | |
305 | int channel_connect_to(const char *host, u_short host_port); | |
306 | int channel_connect_by_listen_adress(u_short listen_port); | |
307 | int x11_connect_display(void); | |
308 | ||
309 | #endif |