1 /* $OpenBSD: channels.h,v 1.130 2017/09/21 19:16:53 markus 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 struct ssh; 67 struct Channel; 68 typedef struct Channel Channel; 69 struct fwd_perm_list; 70 71 typedef void channel_open_fn(struct ssh *, int, int, void *); 72 typedef void channel_callback_fn(struct ssh *, int, void *); 73 typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int); 74 typedef void channel_filter_cleanup_fn(struct ssh *, int, void *); 75 typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *, 76 u_char **, size_t *); 77 78 /* Channel success/failure callbacks */ 79 typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *); 80 typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *); 81 struct channel_confirm { 82 TAILQ_ENTRY(channel_confirm) entry; 83 channel_confirm_cb *cb; 84 channel_confirm_abandon_cb *abandon_cb; 85 void *ctx; 86 }; 87 TAILQ_HEAD(channel_confirms, channel_confirm); 88 89 /* Context for non-blocking connects */ 90 struct channel_connect { 91 char *host; 92 int port; 93 struct addrinfo *ai, *aitop; 94 }; 95 96 /* Callbacks for mux channels back into client-specific code */ 97 typedef int mux_callback_fn(struct ssh *, struct Channel *); 98 99 struct Channel { 100 int type; /* channel type/state */ 101 int self; /* my own channel identifier */ 102 uint32_t remote_id; /* channel identifier for remote peer */ 103 int have_remote_id; /* non-zero if remote_id is valid */ 104 105 u_int istate; /* input from channel (state of receive half) */ 106 u_int ostate; /* output to channel (state of transmit half) */ 107 int flags; /* close sent/rcvd */ 108 int rfd; /* read fd */ 109 int wfd; /* write fd */ 110 int efd; /* extended fd */ 111 int sock; /* sock fd */ 112 int ctl_chan; /* control channel (multiplexed connections) */ 113 int isatty; /* rfd is a tty */ 114 #ifdef _AIX 115 int wfd_isatty; /* wfd is a tty */ 116 #endif 117 int client_tty; /* (client) TTY has been requested */ 118 int force_drain; /* force close on iEOF */ 119 time_t notbefore; /* Pause IO until deadline (time_t) */ 120 int delayed; /* post-select handlers for newly created 121 * channels are delayed until the first call 122 * to a matching pre-select handler. 123 * this way post-select handlers are not 124 * accidentally called if a FD gets reused */ 125 struct sshbuf *input; /* data read from socket, to be sent over 126 * encrypted connection */ 127 struct sshbuf *output; /* data received over encrypted connection for 128 * send on socket */ 129 struct sshbuf *extended; 130 131 char *path; 132 /* path for unix domain sockets, or host name for forwards */ 133 int listening_port; /* port being listened for forwards */ 134 char *listening_addr; /* addr being listened for forwards */ 135 int host_port; /* remote port to connect for forwards */ 136 char *remote_name; /* remote hostname */ 137 138 u_int remote_window; 139 u_int remote_maxpacket; 140 u_int local_window; 141 u_int local_window_max; 142 u_int local_consumed; 143 u_int local_maxpacket; 144 int extended_usage; 145 int single_connection; 146 147 char *ctype; /* type */ 148 149 /* callback */ 150 channel_open_fn *open_confirm; 151 void *open_confirm_ctx; 152 channel_callback_fn *detach_user; 153 int detach_close; 154 struct channel_confirms status_confirms; 155 156 /* filter */ 157 channel_infilter_fn *input_filter; 158 channel_outfilter_fn *output_filter; 159 void *filter_ctx; 160 channel_filter_cleanup_fn *filter_cleanup; 161 162 /* keep boundaries */ 163 int datagram; 164 165 /* non-blocking connect */ 166 /* XXX make this a pointer so the structure can be opaque */ 167 struct channel_connect connect_ctx; 168 169 /* multiplexing protocol hook, called for each packet received */ 170 mux_callback_fn *mux_rcb; 171 void *mux_ctx; 172 int mux_pause; 173 int mux_downstream_id; 174 }; 175 176 #define CHAN_EXTENDED_IGNORE 0 177 #define CHAN_EXTENDED_READ 1 178 #define CHAN_EXTENDED_WRITE 2 179 180 /* default window/packet sizes for tcp/x11-fwd-channel */ 181 #define CHAN_SES_PACKET_DEFAULT (32*1024) 182 #define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT) 183 #define CHAN_TCP_PACKET_DEFAULT (32*1024) 184 #define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT) 185 #define CHAN_X11_PACKET_DEFAULT (16*1024) 186 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT) 187 188 /* possible input states */ 189 #define CHAN_INPUT_OPEN 0 190 #define CHAN_INPUT_WAIT_DRAIN 1 191 #define CHAN_INPUT_WAIT_OCLOSE 2 192 #define CHAN_INPUT_CLOSED 3 193 194 /* possible output states */ 195 #define CHAN_OUTPUT_OPEN 0 196 #define CHAN_OUTPUT_WAIT_DRAIN 1 197 #define CHAN_OUTPUT_WAIT_IEOF 2 198 #define CHAN_OUTPUT_CLOSED 3 199 200 #define CHAN_CLOSE_SENT 0x01 201 #define CHAN_CLOSE_RCVD 0x02 202 #define CHAN_EOF_SENT 0x04 203 #define CHAN_EOF_RCVD 0x08 204 #define CHAN_LOCAL 0x10 205 206 /* Read buffer size */ 207 #define CHAN_RBUF (16*1024) 208 209 /* Hard limit on number of channels */ 210 #define CHANNELS_MAX_CHANNELS (16*1024) 211 212 /* check whether 'efd' is still in use */ 213 #define CHANNEL_EFD_INPUT_ACTIVE(c) \ 214 (c->extended_usage == CHAN_EXTENDED_READ && \ 215 (c->efd != -1 || \ 216 sshbuf_len(c->extended) > 0)) 217 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \ 218 (c->extended_usage == CHAN_EXTENDED_WRITE && \ 219 c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \ 220 sshbuf_len(c->extended) > 0)) 221 222 /* Add channel management structures to SSH transport instance */ 223 void channel_init_channels(struct ssh *ssh); 224 225 /* channel management */ 226 227 Channel *channel_by_id(struct ssh *, int); 228 Channel *channel_by_remote_id(struct ssh *, u_int); 229 Channel *channel_lookup(struct ssh *, int); 230 Channel *channel_new(struct ssh *, char *, int, int, int, int, 231 u_int, u_int, int, char *, int); 232 void channel_set_fds(struct ssh *, int, int, int, int, int, 233 int, int, u_int); 234 void channel_free(struct ssh *, Channel *); 235 void channel_free_all(struct ssh *); 236 void channel_stop_listening(struct ssh *); 237 238 void channel_send_open(struct ssh *, int); 239 void channel_request_start(struct ssh *, int, char *, int); 240 void channel_register_cleanup(struct ssh *, int, 241 channel_callback_fn *, int); 242 void channel_register_open_confirm(struct ssh *, int, 243 channel_open_fn *, void *); 244 void channel_register_filter(struct ssh *, int, channel_infilter_fn *, 245 channel_outfilter_fn *, channel_filter_cleanup_fn *, void *); 246 void channel_register_status_confirm(struct ssh *, int, 247 channel_confirm_cb *, channel_confirm_abandon_cb *, void *); 248 void channel_cancel_cleanup(struct ssh *, int); 249 int channel_close_fd(struct ssh *, int *); 250 void channel_send_window_changes(struct ssh *); 251 252 /* mux proxy support */ 253 254 int channel_proxy_downstream(struct ssh *, Channel *mc); 255 int channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *); 256 257 /* protocol handler */ 258 259 int channel_input_data(int, u_int32_t, struct ssh *); 260 int channel_input_extended_data(int, u_int32_t, struct ssh *); 261 int channel_input_ieof(int, u_int32_t, struct ssh *); 262 int channel_input_oclose(int, u_int32_t, struct ssh *); 263 int channel_input_open_confirmation(int, u_int32_t, struct ssh *); 264 int channel_input_open_failure(int, u_int32_t, struct ssh *); 265 int channel_input_port_open(int, u_int32_t, struct ssh *); 266 int channel_input_window_adjust(int, u_int32_t, struct ssh *); 267 int channel_input_status_confirm(int, u_int32_t, struct ssh *); 268 269 /* file descriptor handling (read/write) */ 270 271 void channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *, 272 u_int*, time_t*); 273 void channel_after_select(struct ssh *, fd_set *, fd_set *); 274 void channel_output_poll(struct ssh *); 275 276 int channel_not_very_much_buffered_data(struct ssh *); 277 void channel_close_all(struct ssh *); 278 int channel_still_open(struct ssh *); 279 char *channel_open_message(struct ssh *); 280 int channel_find_open(struct ssh *); 281 282 /* tcp forwarding */ 283 struct Forward; 284 struct ForwardOptions; 285 void channel_set_af(struct ssh *, int af); 286 void channel_permit_all_opens(struct ssh *); 287 void channel_add_permitted_opens(struct ssh *, char *, int); 288 int channel_add_adm_permitted_opens(struct ssh *, char *, int); 289 void channel_copy_adm_permitted_opens(struct ssh *, 290 const struct fwd_perm_list *); 291 void channel_disable_adm_local_opens(struct ssh *); 292 void channel_update_permitted_opens(struct ssh *, int, int); 293 void channel_clear_permitted_opens(struct ssh *); 294 void channel_clear_adm_permitted_opens(struct ssh *); 295 void channel_print_adm_permitted_opens(struct ssh *); 296 Channel *channel_connect_to_port(struct ssh *, const char *, u_short, 297 char *, char *, int *, const char **); 298 Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *); 299 Channel *channel_connect_stdio_fwd(struct ssh *, const char*, 300 u_short, int, int); 301 Channel *channel_connect_by_listen_address(struct ssh *, const char *, 302 u_short, char *, char *); 303 Channel *channel_connect_by_listen_path(struct ssh *, const char *, 304 char *, char *); 305 int channel_request_remote_forwarding(struct ssh *, struct Forward *); 306 int channel_setup_local_fwd_listener(struct ssh *, struct Forward *, 307 struct ForwardOptions *); 308 int channel_request_rforward_cancel(struct ssh *, struct Forward *); 309 int channel_setup_remote_fwd_listener(struct ssh *, struct Forward *, 310 int *, struct ForwardOptions *); 311 int channel_cancel_rport_listener(struct ssh *, struct Forward *); 312 int channel_cancel_lport_listener(struct ssh *, struct Forward *, 313 int, struct ForwardOptions *); 314 int permitopen_port(const char *); 315 316 /* x11 forwarding */ 317 318 void channel_set_x11_refuse_time(struct ssh *, u_int); 319 int x11_connect_display(struct ssh *); 320 int x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **); 321 void x11_request_forwarding_with_spoofing(struct ssh *, int, 322 const char *, const char *, const char *, int); 323 324 /* channel close */ 325 326 int chan_is_dead(struct ssh *, Channel *, int); 327 void chan_mark_dead(struct ssh *, Channel *); 328 329 /* channel events */ 330 331 void chan_rcvd_oclose(struct ssh *, Channel *); 332 void chan_rcvd_eow(struct ssh *, Channel *); 333 void chan_read_failed(struct ssh *, Channel *); 334 void chan_ibuf_empty(struct ssh *, Channel *); 335 void chan_rcvd_ieof(struct ssh *, Channel *); 336 void chan_write_failed(struct ssh *, Channel *); 337 void chan_obuf_empty(struct ssh *, Channel *); 338 339 #endif 340