channels.h revision 74500
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("$FreeBSD: head/crypto/openssh/channels.h 74500 2001-03-20 02:06:40Z green $"); */ 36/* RCSID("$OpenBSD: channels.h,v 1.22 2000/10/27 07:48:22 markus Exp $"); */ 37 38#ifndef CHANNELS_H 39#define CHANNELS_H 40 41/* Definitions for channel types. */ 42#define SSH_CHANNEL_FREE 0 /* This channel is free (unused). */ 43#define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */ 44#define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */ 45#define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */ 46#define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */ 47#define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */ 48#define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */ 49#define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */ 50#define SSH_CHANNEL_INPUT_DRAINING 8 /* sending remaining data to conn */ 51#define SSH_CHANNEL_OUTPUT_DRAINING 9 /* sending remaining data to app */ 52#define SSH_CHANNEL_LARVAL 10 /* larval session */ 53#define SSH_CHANNEL_MAX_TYPE 11 54 55/* 56 * Data structure for channel data. This is iniailized in channel_allocate 57 * and cleared in channel_free. 58 */ 59struct Channel; 60typedef struct Channel Channel; 61 62typedef void channel_callback_fn(int id, void *arg); 63typedef int channel_filter_fn(struct Channel *c, char *buf, int len); 64 65struct Channel { 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 int isatty; /* rfd is a tty */ 78 Buffer input; /* data read from socket, to be sent over 79 * encrypted connection */ 80 Buffer output; /* data received over encrypted connection for 81 * send on socket */ 82 Buffer extended; 83 char path[200]; /* path for unix domain sockets, or host name 84 * for forwards */ 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 */ 88 89 int remote_window; 90 int remote_maxpacket; 91 int local_window; 92 int local_window_max; 93 int local_consumed; 94 int local_maxpacket; 95 int extended_usage; 96 97 char *ctype; /* type */ 98 99 /* callback */ 100 channel_callback_fn *cb_fn; 101 void *cb_arg; 102 int cb_event; 103 channel_callback_fn *dettach_user; 104 105 /* filter */ 106 channel_filter_fn *input_filter; 107}; 108 109#define CHAN_EXTENDED_IGNORE 0 110#define CHAN_EXTENDED_READ 1 111#define CHAN_EXTENDED_WRITE 2 112 113/* 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) 120 121 122void channel_open(int id); 123void channel_request(int id, char *service, int wantconfirm); 124void channel_request_start(int id, char *service, int wantconfirm); 125void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg); 126void channel_register_cleanup(int id, channel_callback_fn *fn); 127void channel_register_filter(int id, channel_filter_fn *fn); 128void channel_cancel_cleanup(int id); 129Channel *channel_lookup(int id); 130 131int 132channel_new(char *ctype, int type, int rfd, int wfd, int efd, 133 int window, int maxpack, int extended_usage, char *remote_name, 134 int nonblock); 135void 136channel_set_fds(int id, int rfd, int wfd, int efd, 137 int extusage, int nonblock); 138 139void deny_input_open(int type, int plen, void *ctxt); 140 141void channel_input_channel_request(int type, int plen, void *ctxt); 142void channel_input_close(int type, int plen, void *ctxt); 143void channel_input_close_confirmation(int type, int plen, void *ctxt); 144void channel_input_data(int type, int plen, void *ctxt); 145void channel_input_extended_data(int type, int plen, void *ctxt); 146void channel_input_ieof(int type, int plen, void *ctxt); 147void channel_input_oclose(int type, int plen, void *ctxt); 148void channel_input_open_confirmation(int type, int plen, void *ctxt); 149void channel_input_open_failure(int type, int plen, void *ctxt); 150void channel_input_port_open(int type, int plen, void *ctxt); 151void channel_input_window_adjust(int type, int plen, void *ctxt); 152void channel_input_open(int type, int plen, void *ctxt); 153 154/* Sets specific protocol options. */ 155void channel_set_options(int hostname_in_open); 156 157/* 158 * Allocate a new channel object and set its type and socket. Remote_name 159 * must have been allocated with xmalloc; this will free it when the channel 160 * is freed. 161 */ 162int channel_allocate(int type, int sock, char *remote_name); 163 164/* Free the channel and close its socket. */ 165void channel_free(int channel); 166 167/* Add any bits relevant to channels in select bitmasks. */ 168void channel_prepare_select(fd_set * readset, fd_set * writeset); 169 170/* 171 * After select, perform any appropriate operations for channels which have 172 * events pending. 173 */ 174void channel_after_select(fd_set * readset, fd_set * writeset); 175 176/* If there is data to send to the connection, send some of it now. */ 177void channel_output_poll(void); 178 179/* Returns true if no channel has too much buffered data. */ 180int channel_not_very_much_buffered_data(void); 181 182/* This closes any sockets that are listening for connections; this removes 183 any unix domain sockets. */ 184void channel_stop_listening(void); 185 186/* 187 * Closes the sockets of all channels. This is used to close extra file 188 * descriptors after a fork. 189 */ 190void channel_close_all(void); 191 192/* Returns the maximum file descriptor number used by the channels. */ 193int channel_max_fd(void); 194 195/* Returns true if there is still an open channel over the connection. */ 196int channel_still_open(void); 197 198/* 199 * Returns a string containing a list of all open channels. The list is 200 * suitable for displaying to the user. It uses crlf instead of newlines. 201 * The caller should free the string with xfree. 202 */ 203char *channel_open_message(void); 204 205/* 206 * Initiate forwarding of connections to local port "port" through the secure 207 * channel to host:port from remote side. This never returns if there was an 208 * error. 209 */ 210void 211channel_request_local_forwarding(u_short port, const char *host, 212 u_short remote_port, int gateway_ports); 213 214/* 215 * Initiate forwarding of connections to port "port" on remote host through 216 * the secure channel to host:port from local side. This never returns if 217 * there was an error. This registers that open requests for that port are 218 * permitted. 219 */ 220void 221channel_request_remote_forwarding(u_short port, const char *host, 222 u_short remote_port); 223 224/* 225 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually 226 * called by the server, because the user could connect to any port anyway, 227 * and the server has no way to know but to trust the client anyway. 228 */ 229void channel_permit_all_opens(void); 230 231/* 232 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 233 * listening for the port, and sends back a success reply (or disconnect 234 * message if there was an error). This never returns if there was an error. 235 */ 236void channel_input_port_forward_request(int is_root, int gateway_ports); 237 238/* 239 * Creates a port for X11 connections, and starts listening for it. Returns 240 * the display name, or NULL if an error was encountered. 241 */ 242char *x11_create_display(int screen); 243 244/* 245 * Creates an internet domain socket for listening for X11 connections. 246 * Returns a suitable value for the DISPLAY variable, or NULL if an error 247 * occurs. 248 */ 249char *x11_create_display_inet(int screen, int x11_display_offset); 250 251/* 252 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 253 * the remote channel number. We should do whatever we want, and respond 254 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 255 */ 256void x11_input_open(int type, int plen, void *ctxt); 257 258/* 259 * Requests forwarding of X11 connections. This should be called on the 260 * client only. 261 */ 262void x11_request_forwarding(void); 263 264/* 265 * Requests forwarding for X11 connections, with authentication spoofing. 266 * This should be called in the client only. 267 */ 268void 269x11_request_forwarding_with_spoofing(int client_session_id, 270 const char *proto, const char *data); 271 272/* Sends a message to the server to request authentication fd forwarding. */ 273void auth_request_forwarding(void); 274 275/* 276 * Returns the name of the forwarded authentication socket. Returns NULL if 277 * there is no forwarded authentication socket. The returned value points to 278 * a static buffer. 279 */ 280char *auth_get_socket_name(void); 281 282/* 283 * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. 284 * This starts forwarding authentication requests. 285 */ 286int auth_input_request_forwarding(struct passwd * pw); 287 288/* This is called to process an SSH_SMSG_AGENT_OPEN message. */ 289void auth_input_open_request(int type, int plen, void *ctxt); 290 291/* XXX */ 292int channel_connect_to(const char *host, u_short host_port); 293int x11_connect_display(void); 294 295#endif 296