channels.h revision 65668
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 1.19 2000/09/07 21:13:37 markus Exp $"); */ 36 37#ifndef CHANNELS_H 38#define CHANNELS_H 39 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 53 54/* 55 * Data structure for channel data. This is iniailized in channel_allocate 56 * and cleared in channel_free. 57 */ 58struct Channel; 59typedef struct Channel Channel; 60 61typedef void channel_callback_fn(int id, void *arg); 62typedef int channel_filter_fn(struct Channel *c, char *buf, int len); 63 64struct Channel { 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 79 * send on socket */ 80 Buffer extended; 81 char path[200]; /* path for unix domain sockets, or host name 82 * for forwards */ 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 */ 86 87 int remote_window; 88 int remote_maxpacket; 89 int local_window; 90 int local_window_max; 91 int local_consumed; 92 int local_maxpacket; 93 int extended_usage; 94 95 char *ctype; /* type */ 96 97 /* callback */ 98 channel_callback_fn *cb_fn; 99 void *cb_arg; 100 int cb_event; 101 channel_callback_fn *dettach_user; 102 103 /* filter */ 104 channel_filter_fn *input_filter; 105}; 106 107#define CHAN_EXTENDED_IGNORE 0 108#define CHAN_EXTENDED_READ 1 109#define CHAN_EXTENDED_WRITE 2 110 111/* 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) 118 119 120void channel_set_fds(int id, int rfd, int wfd, int efd, int extusage); 121void channel_open(int id); 122void channel_request(int id, char *service, int wantconfirm); 123void channel_request_start(int id, char *service, int wantconfirm); 124void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg); 125void channel_register_cleanup(int id, channel_callback_fn *fn); 126void channel_register_filter(int id, channel_filter_fn *fn); 127void channel_cancel_cleanup(int id); 128Channel *channel_lookup(int id); 129 130int 131channel_new(char *ctype, int type, int rfd, int wfd, int efd, 132 int window, int maxpack, int extended_usage, char *remote_name); 133 134void channel_input_channel_request(int type, int plen); 135void channel_input_close(int type, int plen); 136void channel_input_close_confirmation(int type, int plen); 137void channel_input_data(int type, int plen); 138void channel_input_extended_data(int type, int plen); 139void channel_input_ieof(int type, int plen); 140void channel_input_oclose(int type, int plen); 141void channel_input_open_confirmation(int type, int plen); 142void channel_input_open_failure(int type, int plen); 143void channel_input_port_open(int type, int plen); 144void channel_input_window_adjust(int type, int plen); 145void channel_input_open(int type, int plen); 146 147/* Sets specific protocol options. */ 148void channel_set_options(int hostname_in_open); 149 150/* 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 153 * is freed. 154 */ 155int channel_allocate(int type, int sock, char *remote_name); 156 157/* Free the channel and close its socket. */ 158void channel_free(int channel); 159 160/* Add any bits relevant to channels in select bitmasks. */ 161void channel_prepare_select(fd_set * readset, fd_set * writeset); 162 163/* 164 * After select, perform any appropriate operations for channels which have 165 * events pending. 166 */ 167void channel_after_select(fd_set * readset, fd_set * writeset); 168 169/* If there is data to send to the connection, send some of it now. */ 170void channel_output_poll(void); 171 172/* Returns true if no channel has too much buffered data. */ 173int channel_not_very_much_buffered_data(void); 174 175/* This closes any sockets that are listening for connections; this removes 176 any unix domain sockets. */ 177void channel_stop_listening(void); 178 179/* 180 * Closes the sockets of all channels. This is used to close extra file 181 * descriptors after a fork. 182 */ 183void channel_close_all(void); 184 185/* Returns the maximum file descriptor number used by the channels. */ 186int channel_max_fd(void); 187 188/* Returns true if there is still an open channel over the connection. */ 189int channel_still_open(void); 190 191/* 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. 195 */ 196char *channel_open_message(void); 197 198/* 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 201 * error. 202 */ 203void 204channel_request_local_forwarding(u_short port, const char *host, 205 u_short remote_port, int gateway_ports); 206 207/* 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 211 * permitted. 212 */ 213void 214channel_request_remote_forwarding(u_short port, const char *host, 215 u_short remote_port); 216 217/* 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. 221 */ 222void channel_permit_all_opens(void); 223 224/* 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. 228 */ 229void channel_input_port_forward_request(int is_root, int gateway_ports); 230 231/* 232 * Creates a port for X11 connections, and starts listening for it. Returns 233 * the display name, or NULL if an error was encountered. 234 */ 235char *x11_create_display(int screen); 236 237/* 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 240 * occurs. 241 */ 242char *x11_create_display_inet(int screen, int x11_display_offset); 243 244/* 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. 248 */ 249void x11_input_open(int type, int plen); 250 251/* 252 * Requests forwarding of X11 connections. This should be called on the 253 * client only. 254 */ 255void x11_request_forwarding(void); 256 257/* 258 * Requests forwarding for X11 connections, with authentication spoofing. 259 * This should be called in the client only. 260 */ 261void 262x11_request_forwarding_with_spoofing(int client_session_id, 263 const char *proto, const char *data); 264 265/* Sends a message to the server to request authentication fd forwarding. */ 266void auth_request_forwarding(void); 267 268/* 269 * Returns the name of the forwarded authentication socket. Returns NULL if 270 * there is no forwarded authentication socket. The returned value points to 271 * a static buffer. 272 */ 273char *auth_get_socket_name(void); 274 275/* 276 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. 277 * This starts forwarding authentication requests. 278 */ 279int auth_input_request_forwarding(struct passwd * pw); 280 281/* This is called to process an SSH_SMSG_AGENT_OPEN message. */ 282void auth_input_open_request(int type, int plen); 283 284/* XXX */ 285int channel_connect_to(const char *host, u_short host_port); 286int x11_connect_display(void); 287 288#endif 289