1 /* $OpenBSD: channels.h,v 1.132 2018/10/04 00:10:11 djm Exp $ */ 2 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 */ 14 /* 15 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #ifndef CHANNEL_H 39 #define CHANNEL_H 40 41 /* Definitions for channel types. */ 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_LARVAL 10 /* larval session */ 50 #define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */ 51 #define SSH_CHANNEL_CONNECTING 12 52 #define SSH_CHANNEL_DYNAMIC 13 53 #define SSH_CHANNEL_ZOMBIE 14 /* Almost dead. */ 54 #define SSH_CHANNEL_MUX_LISTENER 15 /* Listener for mux conn. */ 55 #define SSH_CHANNEL_MUX_CLIENT 16 /* Conn. to mux slave */ 56 #define SSH_CHANNEL_ABANDONED 17 /* Abandoned session, eg mux */ 57 #define SSH_CHANNEL_UNIX_LISTENER 18 /* Listening on a domain socket. */ 58 #define SSH_CHANNEL_RUNIX_LISTENER 19 /* Listening to a R-style domain socket. */ 59 #define SSH_CHANNEL_MUX_PROXY 20 /* proxy channel for mux-slave */ 60 #define SSH_CHANNEL_RDYNAMIC_OPEN 21 /* reverse SOCKS, parsing request */ 61 #define SSH_CHANNEL_RDYNAMIC_FINISH 22 /* reverse SOCKS, finishing connect */ 62 #define SSH_CHANNEL_MAX_TYPE 23 63 64 #define CHANNEL_CANCEL_PORT_STATIC -1 65 66 /* TCP forwarding */ 67 #define FORWARD_DENY 0 68 #define FORWARD_REMOTE (1) 69 #define FORWARD_LOCAL (1<<1) 70 #define FORWARD_ALLOW (FORWARD_REMOTE|FORWARD_LOCAL) 71 72 #define FORWARD_ADM 0x100 73 #define FORWARD_USER 0x101 74 75 struct ssh; 76 struct Channel; 77 typedef struct Channel Channel; 78 struct fwd_perm_list; 79 80 typedef void channel_open_fn(struct ssh *, int, int, void *); 81 typedef void channel_callback_fn(struct ssh *, int, void *); 82 typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int); 83 typedef void channel_filter_cleanup_fn(struct ssh *, int, void *); 84 typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *, 85 u_char **, size_t *); 86 87 /* Channel success/failure callbacks */ 88 typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *); 89 typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *); 90 struct channel_confirm { 91 TAILQ_ENTRY(channel_confirm) entry; 92 channel_confirm_cb *cb; 93 channel_confirm_abandon_cb *abandon_cb; 94 void *ctx; 95 }; 96 TAILQ_HEAD(channel_confirms, channel_confirm); 97 98 /* Context for non-blocking connects */ 99 struct channel_connect { 100 char *host; 101 int port; 102 struct addrinfo *ai, *aitop; 103 }; 104 105 /* Callbacks for mux channels back into client-specific code */ 106 typedef int mux_callback_fn(struct ssh *, struct Channel *); 107 108 struct Channel { 109 int type; /* channel type/state */ 110 int self; /* my own channel identifier */ 111 uint32_t remote_id; /* channel identifier for remote peer */ 112 int have_remote_id; /* non-zero if remote_id is valid */ 113 114 u_int istate; /* input from channel (state of receive half) */ 115 u_int ostate; /* output to channel (state of transmit half) */ 116 int flags; /* close sent/rcvd */ 117 int rfd; /* read fd */ 118 int wfd; /* write fd */ 119 int efd; /* extended fd */ 120 int sock; /* sock fd */ 121 int ctl_chan; /* control channel (multiplexed connections) */ 122 int isatty; /* rfd is a tty */ 123 #ifdef _AIX 124 int wfd_isatty; /* wfd is a tty */ 125 #endif 126 int client_tty; /* (client) TTY has been requested */ 127 int force_drain; /* force close on iEOF */ 128 time_t notbefore; /* Pause IO until deadline (time_t) */ 129 int delayed; /* post-select handlers for newly created 130 * channels are delayed until the first call 131 * to a matching pre-select handler. 132 * this way post-select handlers are not 133 * accidentally called if a FD gets reused */ 134 struct sshbuf *input; /* data read from socket, to be sent over 135 * encrypted connection */ 136 struct sshbuf *output; /* data received over encrypted connection for 137 * send on socket */ 138 struct sshbuf *extended; 139 140 char *path; 141 /* path for unix domain sockets, or host name for forwards */ 142 int listening_port; /* port being listened for forwards */ 143 char *listening_addr; /* addr being listened for forwards */ 144 int host_port; /* remote port to connect for forwards */ 145 char *remote_name; /* remote hostname */ 146 147 u_int remote_window; 148 u_int remote_maxpacket; 149 u_int local_window; 150 u_int local_window_max; 151 u_int local_consumed; 152 u_int local_maxpacket; 153 int extended_usage; 154 int single_connection; 155 156 char *ctype; /* type */ 157 158 /* callback */ 159 channel_open_fn *open_confirm; 160 void *open_confirm_ctx; 161 channel_callback_fn *detach_user; 162 int detach_close; 163 struct channel_confirms status_confirms; 164 165 /* filter */ 166 channel_infilter_fn *input_filter; 167 channel_outfilter_fn *output_filter; 168 void *filter_ctx; 169 channel_filter_cleanup_fn *filter_cleanup; 170 171 /* keep boundaries */ 172 int datagram; 173 174 /* non-blocking connect */ 175 /* XXX make this a pointer so the structure can be opaque */ 176 struct channel_connect connect_ctx; 177 178 /* multiplexing protocol hook, called for each packet received */ 179 mux_callback_fn *mux_rcb; 180 void *mux_ctx; 181 int mux_pause; 182 int mux_downstream_id; 183 }; 184 185 #define CHAN_EXTENDED_IGNORE 0 186 #define CHAN_EXTENDED_READ 1 187 #define CHAN_EXTENDED_WRITE 2 188 189 /* default window/packet sizes for tcp/x11-fwd-channel */ 190 #define CHAN_SES_PACKET_DEFAULT (32*1024) 191 #define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT) 192 #define CHAN_TCP_PACKET_DEFAULT (32*1024) 193 #define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT) 194 #define CHAN_X11_PACKET_DEFAULT (16*1024) 195 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT) 196 197 /* possible input states */ 198 #define CHAN_INPUT_OPEN 0 199 #define CHAN_INPUT_WAIT_DRAIN 1 200 #define CHAN_INPUT_WAIT_OCLOSE 2 201 #define CHAN_INPUT_CLOSED 3 202 203 /* possible output states */ 204 #define CHAN_OUTPUT_OPEN 0 205 #define CHAN_OUTPUT_WAIT_DRAIN 1 206 #define CHAN_OUTPUT_WAIT_IEOF 2 207 #define CHAN_OUTPUT_CLOSED 3 208 209 #define CHAN_CLOSE_SENT 0x01 210 #define CHAN_CLOSE_RCVD 0x02 211 #define CHAN_EOF_SENT 0x04 212 #define CHAN_EOF_RCVD 0x08 213 #define CHAN_LOCAL 0x10 214 215 /* Read buffer size */ 216 #define CHAN_RBUF (16*1024) 217 218 /* Hard limit on number of channels */ 219 #define CHANNELS_MAX_CHANNELS (16*1024) 220 221 /* check whether 'efd' is still in use */ 222 #define CHANNEL_EFD_INPUT_ACTIVE(c) \ 223 (c->extended_usage == CHAN_EXTENDED_READ && \ 224 (c->efd != -1 || \ 225 sshbuf_len(c->extended) > 0)) 226 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \ 227 (c->extended_usage == CHAN_EXTENDED_WRITE && \ 228 c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \ 229 sshbuf_len(c->extended) > 0)) 230 231 /* Add channel management structures to SSH transport instance */ 232 void channel_init_channels(struct ssh *ssh); 233 234 /* channel management */ 235 236 Channel *channel_by_id(struct ssh *, int); 237 Channel *channel_by_remote_id(struct ssh *, u_int); 238 Channel *channel_lookup(struct ssh *, int); 239 Channel *channel_new(struct ssh *, char *, int, int, int, int, 240 u_int, u_int, int, char *, int); 241 void channel_set_fds(struct ssh *, int, int, int, int, int, 242 int, int, u_int); 243 void channel_free(struct ssh *, Channel *); 244 void channel_free_all(struct ssh *); 245 void channel_stop_listening(struct ssh *); 246 247 void channel_send_open(struct ssh *, int); 248 void channel_request_start(struct ssh *, int, char *, int); 249 void channel_register_cleanup(struct ssh *, int, 250 channel_callback_fn *, int); 251 void channel_register_open_confirm(struct ssh *, int, 252 channel_open_fn *, void *); 253 void channel_register_filter(struct ssh *, int, channel_infilter_fn *, 254 channel_outfilter_fn *, channel_filter_cleanup_fn *, void *); 255 void channel_register_status_confirm(struct ssh *, int, 256 channel_confirm_cb *, channel_confirm_abandon_cb *, void *); 257 void channel_cancel_cleanup(struct ssh *, int); 258 int channel_close_fd(struct ssh *, int *); 259 void channel_send_window_changes(struct ssh *); 260 261 /* mux proxy support */ 262 263 int channel_proxy_downstream(struct ssh *, Channel *mc); 264 int channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *); 265 266 /* protocol handler */ 267 268 int channel_input_data(int, u_int32_t, struct ssh *); 269 int channel_input_extended_data(int, u_int32_t, struct ssh *); 270 int channel_input_ieof(int, u_int32_t, struct ssh *); 271 int channel_input_oclose(int, u_int32_t, struct ssh *); 272 int channel_input_open_confirmation(int, u_int32_t, struct ssh *); 273 int channel_input_open_failure(int, u_int32_t, struct ssh *); 274 int channel_input_port_open(int, u_int32_t, struct ssh *); 275 int channel_input_window_adjust(int, u_int32_t, struct ssh *); 276 int channel_input_status_confirm(int, u_int32_t, struct ssh *); 277 278 /* file descriptor handling (read/write) */ 279 280 void channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *, 281 u_int*, time_t*); 282 void channel_after_select(struct ssh *, fd_set *, fd_set *); 283 void channel_output_poll(struct ssh *); 284 285 int channel_not_very_much_buffered_data(struct ssh *); 286 void channel_close_all(struct ssh *); 287 int channel_still_open(struct ssh *); 288 const char *channel_format_extended_usage(const Channel *); 289 char *channel_open_message(struct ssh *); 290 int channel_find_open(struct ssh *); 291 292 /* tcp forwarding */ 293 struct Forward; 294 struct ForwardOptions; 295 void channel_set_af(struct ssh *, int af); 296 void channel_permit_all(struct ssh *, int); 297 void channel_add_permission(struct ssh *, int, int, char *, int); 298 void channel_clear_permission(struct ssh *, int, int); 299 void channel_disable_admin(struct ssh *, int); 300 void channel_update_permission(struct ssh *, int, int); 301 Channel *channel_connect_to_port(struct ssh *, const char *, u_short, 302 char *, char *, int *, const char **); 303 Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *); 304 Channel *channel_connect_stdio_fwd(struct ssh *, const char*, 305 u_short, int, int); 306 Channel *channel_connect_by_listen_address(struct ssh *, const char *, 307 u_short, char *, char *); 308 Channel *channel_connect_by_listen_path(struct ssh *, const char *, 309 char *, char *); 310 int channel_request_remote_forwarding(struct ssh *, struct Forward *); 311 int channel_setup_local_fwd_listener(struct ssh *, struct Forward *, 312 struct ForwardOptions *); 313 int channel_request_rforward_cancel(struct ssh *, struct Forward *); 314 int channel_setup_remote_fwd_listener(struct ssh *, struct Forward *, 315 int *, struct ForwardOptions *); 316 int channel_cancel_rport_listener(struct ssh *, struct Forward *); 317 int channel_cancel_lport_listener(struct ssh *, struct Forward *, 318 int, struct ForwardOptions *); 319 int permitopen_port(const char *); 320 321 /* x11 forwarding */ 322 323 void channel_set_x11_refuse_time(struct ssh *, u_int); 324 int x11_connect_display(struct ssh *); 325 int x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **); 326 void x11_request_forwarding_with_spoofing(struct ssh *, int, 327 const char *, const char *, const char *, int); 328 329 /* channel close */ 330 331 int chan_is_dead(struct ssh *, Channel *, int); 332 void chan_mark_dead(struct ssh *, Channel *); 333 334 /* channel events */ 335 336 void chan_rcvd_oclose(struct ssh *, Channel *); 337 void chan_rcvd_eow(struct ssh *, Channel *); 338 void chan_read_failed(struct ssh *, Channel *); 339 void chan_ibuf_empty(struct ssh *, Channel *); 340 void chan_rcvd_ieof(struct ssh *, Channel *); 341 void chan_write_failed(struct ssh *, Channel *); 342 void chan_obuf_empty(struct ssh *, Channel *); 343 344 #endif 345