crypto/openssh/channels.h

   1 /* $OpenBSD: channels.h,v 1.115 2014/07/15 15:54:14 millert 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_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_RPORT_LISTENER      11      /* Listening to a R-style port  */
  53 #define SSH_CHANNEL_CONNECTING          12
  54 #define SSH_CHANNEL_DYNAMIC             13
  55 #define SSH_CHANNEL_ZOMBIE              14      /* Almost dead. */
  56 #define SSH_CHANNEL_MUX_LISTENER        15      /* Listener for mux conn. */
  57 #define SSH_CHANNEL_MUX_CLIENT          16      /* Conn. to mux slave */
  58 #define SSH_CHANNEL_ABANDONED           17      /* Abandoned session, eg mux */
  59 #define SSH_CHANNEL_UNIX_LISTENER       18      /* Listening on a domain socket. */
  60 #define SSH_CHANNEL_RUNIX_LISTENER      19      /* Listening to a R-style domain socket. */
  61 #define SSH_CHANNEL_MAX_TYPE            20
  62
  63 #define CHANNEL_CANCEL_PORT_STATIC      -1
  64
  65 struct Channel;
  66 typedef struct Channel Channel;
  67
  68 typedef void channel_open_fn(int, int, void *);
  69 typedef void channel_callback_fn(int, void *);
  70 typedef int channel_infilter_fn(struct Channel *, char *, int);
  71 typedef void channel_filter_cleanup_fn(int, void *);
  72 typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
  73
  74 /* Channel success/failure callbacks */
  75 typedef void channel_confirm_cb(int, struct Channel *, void *);
  76 typedef void channel_confirm_abandon_cb(struct Channel *, void *);
  77 struct channel_confirm {
  78         TAILQ_ENTRY(channel_confirm) entry;
  79         channel_confirm_cb *cb;
  80         channel_confirm_abandon_cb *abandon_cb;
  81         void *ctx;
  82 };
  83 TAILQ_HEAD(channel_confirms, channel_confirm);
  84
  85 /* Context for non-blocking connects */
  86 struct channel_connect {
  87         char *host;
  88         int port;
  89         struct addrinfo *ai, *aitop;
  90 };
  91
  92 /* Callbacks for mux channels back into client-specific code */
  93 typedef int mux_callback_fn(struct Channel *);
  94
  95 struct Channel {
  96         int     type;           /* channel type/state */
  97         int     self;           /* my own channel identifier */
  98         int     remote_id;      /* channel identifier for remote peer */
  99         u_int   istate;         /* input from channel (state of receive half) */
 100         u_int   ostate;         /* output to channel  (state of transmit half) */
 101         int     flags;          /* close sent/rcvd */
 102         int     rfd;            /* read fd */
 103         int     wfd;            /* write fd */
 104         int     efd;            /* extended fd */
 105         int     sock;           /* sock fd */
 106         int     ctl_chan;       /* control channel (multiplexed connections) */
 107         int     isatty;         /* rfd is a tty */
 108 #ifdef _AIX
 109         int     wfd_isatty;     /* wfd is a tty */
 110 #endif
 111         int     client_tty;     /* (client) TTY has been requested */
 112         int     force_drain;    /* force close on iEOF */
 113         time_t  notbefore;      /* Pause IO until deadline (time_t) */
 114         int     delayed;        /* post-select handlers for newly created
 115                                  * channels are delayed until the first call
 116                                  * to a matching pre-select handler.
 117                                  * this way post-select handlers are not
 118                                  * accidentally called if a FD gets reused */
 119         Buffer  input;          /* data read from socket, to be sent over
 120                                  * encrypted connection */
 121         Buffer  output;         /* data received over encrypted connection for
 122                                  * send on socket */
 123         Buffer  extended;
 124         char    *path;
 125                 /* path for unix domain sockets, or host name for forwards */
 126         int     listening_port; /* port being listened for forwards */
 127         char   *listening_addr; /* addr being listened for forwards */
 128         int     host_port;      /* remote port to connect for forwards */
 129         char   *remote_name;    /* remote hostname */
 130
 131         u_int   remote_window;
 132         u_int   remote_maxpacket;
 133         u_int   local_window;
 134         u_int   local_window_max;
 135         u_int   local_consumed;
 136         u_int   local_maxpacket;
 137         int     dynamic_window;
 138         int     extended_usage;
 139         int     single_connection;
 140         u_int   tcpwinsz;
 141
 142         char   *ctype;          /* type */
 143
 144         /* callback */
 145         channel_open_fn         *open_confirm;
 146         void                    *open_confirm_ctx;
 147         channel_callback_fn     *detach_user;
 148         int                     detach_close;
 149         struct channel_confirms status_confirms;
 150
 151         /* filter */
 152         channel_infilter_fn     *input_filter;
 153         channel_outfilter_fn    *output_filter;
 154         void                    *filter_ctx;
 155         channel_filter_cleanup_fn *filter_cleanup;
 156
 157         /* keep boundaries */
 158         int                     datagram;
 159
 160         /* non-blocking connect */
 161         struct channel_connect  connect_ctx;
 162
 163         /* multiplexing protocol hook, called for each packet received */
 164         mux_callback_fn         *mux_rcb;
 165         void                    *mux_ctx;
 166         int                     mux_pause;
 167 };
 168
 169 #define CHAN_EXTENDED_IGNORE            0
 170 #define CHAN_EXTENDED_READ              1
 171 #define CHAN_EXTENDED_WRITE             2
 172
 173 /* default window/packet sizes for tcp/x11-fwd-channel */
 174 #define CHAN_SES_PACKET_DEFAULT (32*1024)
 175 #define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
 176
 177 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
 178 #define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
 179
 180 #define CHAN_X11_PACKET_DEFAULT (16*1024)
 181 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
 182
 183 /* possible input states */
 184 #define CHAN_INPUT_OPEN                 0
 185 #define CHAN_INPUT_WAIT_DRAIN           1
 186 #define CHAN_INPUT_WAIT_OCLOSE          2
 187 #define CHAN_INPUT_CLOSED               3
 188
 189 /* possible output states */
 190 #define CHAN_OUTPUT_OPEN                0
 191 #define CHAN_OUTPUT_WAIT_DRAIN          1
 192 #define CHAN_OUTPUT_WAIT_IEOF           2
 193 #define CHAN_OUTPUT_CLOSED              3
 194
 195 #define CHAN_CLOSE_SENT                 0x01
 196 #define CHAN_CLOSE_RCVD                 0x02
 197 #define CHAN_EOF_SENT                   0x04
 198 #define CHAN_EOF_RCVD                   0x08
 199 #define CHAN_LOCAL                      0x10
 200
 201 #define CHAN_RBUF       16*1024
 202
 203 /* check whether 'efd' is still in use */
 204 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 205         (compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
 206         (c->efd != -1 || \
 207         buffer_len(&c->extended) > 0))
 208 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 209         (compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
 210         c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
 211         buffer_len(&c->extended) > 0))
 212
 213 /* channel management */
 214
 215 Channel *channel_by_id(int);
 216 Channel *channel_lookup(int);
 217 Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
 218 void     channel_set_fds(int, int, int, int, int, int, int, u_int);
 219 void     channel_free(Channel *);
 220 void     channel_free_all(void);
 221 void     channel_stop_listening(void);
 222
 223 void     channel_send_open(int);
 224 void     channel_request_start(int, char *, int);
 225 void     channel_register_cleanup(int, channel_callback_fn *, int);
 226 void     channel_register_open_confirm(int, channel_open_fn *, void *);
 227 void     channel_register_filter(int, channel_infilter_fn *,
 228     channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
 229 void     channel_register_status_confirm(int, channel_confirm_cb *,
 230     channel_confirm_abandon_cb *, void *);
 231 void     channel_cancel_cleanup(int);
 232 int      channel_close_fd(int *);
 233 void     channel_send_window_changes(void);
 234
 235 /* protocol handler */
 236
 237 void     channel_input_close(int, u_int32_t, void *);
 238 void     channel_input_close_confirmation(int, u_int32_t, void *);
 239 void     channel_input_data(int, u_int32_t, void *);
 240 void     channel_input_extended_data(int, u_int32_t, void *);
 241 void     channel_input_ieof(int, u_int32_t, void *);
 242 void     channel_input_oclose(int, u_int32_t, void *);
 243 void     channel_input_open_confirmation(int, u_int32_t, void *);
 244 void     channel_input_open_failure(int, u_int32_t, void *);
 245 void     channel_input_port_open(int, u_int32_t, void *);
 246 void     channel_input_window_adjust(int, u_int32_t, void *);
 247 void     channel_input_status_confirm(int, u_int32_t, void *);
 248
 249 /* file descriptor handling (read/write) */
 250
 251 void     channel_prepare_select(fd_set **, fd_set **, int *, u_int*,
 252              time_t*, int);
 253 void     channel_after_select(fd_set *, fd_set *);
 254 int      channel_output_poll(void);
 255
 256 int      channel_not_very_much_buffered_data(void);
 257 void     channel_close_all(void);
 258 int      channel_still_open(void);
 259 char    *channel_open_message(void);
 260 int      channel_find_open(void);
 261
 262 /* tcp forwarding */
 263 struct Forward;
 264 struct ForwardOptions;
 265 void     channel_set_af(int af);
 266 void     channel_permit_all_opens(void);
 267 void     channel_add_permitted_opens(char *, int);
 268 int      channel_add_adm_permitted_opens(char *, int);
 269 void     channel_disable_adm_local_opens(void);
 270 void     channel_update_permitted_opens(int, int);
 271 void     channel_clear_permitted_opens(void);
 272 void     channel_clear_adm_permitted_opens(void);
 273 void     channel_print_adm_permitted_opens(void);
 274 int      channel_input_port_forward_request(int, struct ForwardOptions *);
 275 Channel *channel_connect_to_port(const char *, u_short, char *, char *);
 276 Channel *channel_connect_to_path(const char *, char *, char *);
 277 Channel *channel_connect_stdio_fwd(const char*, u_short, int, int);
 278 Channel *channel_connect_by_listen_address(const char *, u_short,
 279              char *, char *);
 280 Channel *channel_connect_by_listen_path(const char *, char *, char *);
 281 int      channel_request_remote_forwarding(struct Forward *);
 282 int      channel_setup_local_fwd_listener(struct Forward *, struct ForwardOptions *);
 283 int      channel_request_rforward_cancel(struct Forward *);
 284 int      channel_setup_remote_fwd_listener(struct Forward *, int *, struct ForwardOptions *);
 285 int      channel_cancel_rport_listener(struct Forward *);
 286 int      channel_cancel_lport_listener(struct Forward *, int, struct ForwardOptions *);
 287 int      permitopen_port(const char *);
 288
 289 /* x11 forwarding */
 290
 291 int      x11_connect_display(void);
 292 int      x11_create_display_inet(int, int, int, u_int *, int **);
 293 void     x11_input_open(int, u_int32_t, void *);
 294 void     x11_request_forwarding_with_spoofing(int, const char *, const char *,
 295              const char *, int);
 296 void     deny_input_open(int, u_int32_t, void *);
 297
 298 /* agent forwarding */
 299
 300 void     auth_request_forwarding(void);
 301
 302 /* channel close */
 303
 304 int      chan_is_dead(Channel *, int);
 305 void     chan_mark_dead(Channel *);
 306
 307 /* channel events */
 308
 309 void     chan_rcvd_oclose(Channel *);
 310 void     chan_rcvd_eow(Channel *);      /* SSH2-only */
 311 void     chan_read_failed(Channel *);
 312 void     chan_ibuf_empty(Channel *);
 313
 314 void     chan_rcvd_ieof(Channel *);
 315 void     chan_write_failed(Channel *);
 316 void     chan_obuf_empty(Channel *);
 317
 318 /* hpn handler */
 319 void     channel_set_hpn(int, int);
 320
 321 #endif