channels.h

   1 /* $OpenBSD: channels.h,v 1.104 2010/05/14 23:29:23 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_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_MAX_TYPE            17
  59
  60 struct Channel;
  61 typedef struct Channel Channel;
  62
  63 typedef void channel_open_fn(int, int, void *);
  64 typedef void channel_callback_fn(int, void *);
  65 typedef int channel_infilter_fn(struct Channel *, char *, int);
  66 typedef void channel_filter_cleanup_fn(int, void *);
  67 typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
  68
  69 /* Channel success/failure callbacks */
  70 typedef void channel_confirm_cb(int, struct Channel *, void *);
  71 typedef void channel_confirm_abandon_cb(struct Channel *, void *);
  72 struct channel_confirm {
  73         TAILQ_ENTRY(channel_confirm) entry;
  74         channel_confirm_cb *cb;
  75         channel_confirm_abandon_cb *abandon_cb;
  76         void *ctx;
  77 };
  78 TAILQ_HEAD(channel_confirms, channel_confirm);
  79
  80 /* Context for non-blocking connects */
  81 struct channel_connect {
  82         char *host;
  83         int port;
  84         struct addrinfo *ai, *aitop;
  85 };
  86
  87 /* Callbacks for mux channels back into client-specific code */
  88 typedef int mux_callback_fn(struct Channel *);
  89
  90 struct Channel {
  91         int     type;           /* channel type/state */
  92         int     self;           /* my own channel identifier */
  93         int     remote_id;      /* channel identifier for remote peer */
  94         u_int   istate;         /* input from channel (state of receive half) */
  95         u_int   ostate;         /* output to channel  (state of transmit half) */
  96         int     flags;          /* close sent/rcvd */
  97         int     rfd;            /* read fd */
  98         int     wfd;            /* write fd */
  99         int     efd;            /* extended fd */
 100         int     sock;           /* sock fd */
 101         int     ctl_chan;       /* control channel (multiplexed connections) */
 102         int     isatty;         /* rfd is a tty */
 103         int     wfd_isatty;     /* wfd is a tty */
 104         int     client_tty;     /* (client) TTY has been requested */
 105         int     force_drain;    /* force close on iEOF */
 106         int     delayed;        /* post-select handlers for newly created
 107                                  * channels are delayed until the first call
 108                                  * to a matching pre-select handler.
 109                                  * this way post-select handlers are not
 110                                  * accidenly called if a FD gets reused */
 111         Buffer  input;          /* data read from socket, to be sent over
 112                                  * encrypted connection */
 113         Buffer  output;         /* data received over encrypted connection for
 114                                  * send on socket */
 115         Buffer  extended;
 116         char    *path;
 117                 /* path for unix domain sockets, or host name for forwards */
 118         int     listening_port; /* port being listened for forwards */
 119         int     host_port;      /* remote port to connect for forwards */
 120         char   *remote_name;    /* remote hostname */
 121
 122         u_int   remote_window;
 123         u_int   remote_maxpacket;
 124         u_int   local_window;
 125         u_int   local_window_max;
 126         u_int   local_consumed;
 127         u_int   local_maxpacket;
 128         int     extended_usage;
 129         int     single_connection;
 130
 131         char   *ctype;          /* type */
 132
 133         /* callback */
 134         channel_open_fn         *open_confirm;
 135         void                    *open_confirm_ctx;
 136         channel_callback_fn     *detach_user;
 137         int                     detach_close;
 138         struct channel_confirms status_confirms;
 139
 140         /* filter */
 141         channel_infilter_fn     *input_filter;
 142         channel_outfilter_fn    *output_filter;
 143         void                    *filter_ctx;
 144         channel_filter_cleanup_fn *filter_cleanup;
 145
 146         /* keep boundaries */
 147         int                     datagram;
 148
 149         /* non-blocking connect */
 150         struct channel_connect  connect_ctx;
 151
 152         /* multiplexing protocol hook, called for each packet received */
 153         mux_callback_fn         *mux_rcb;
 154         void                    *mux_ctx;
 155         int                     mux_pause;
 156 };
 157
 158 #define CHAN_EXTENDED_IGNORE            0
 159 #define CHAN_EXTENDED_READ              1
 160 #define CHAN_EXTENDED_WRITE             2
 161
 162 /* default window/packet sizes for tcp/x11-fwd-channel */
 163 #define CHAN_SES_PACKET_DEFAULT (32*1024)
 164 #define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT)
 165 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
 166 #define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT)
 167 #define CHAN_X11_PACKET_DEFAULT (16*1024)
 168 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
 169
 170 /* possible input states */
 171 #define CHAN_INPUT_OPEN                 0
 172 #define CHAN_INPUT_WAIT_DRAIN           1
 173 #define CHAN_INPUT_WAIT_OCLOSE          2
 174 #define CHAN_INPUT_CLOSED               3
 175
 176 /* possible output states */
 177 #define CHAN_OUTPUT_OPEN                0
 178 #define CHAN_OUTPUT_WAIT_DRAIN          1
 179 #define CHAN_OUTPUT_WAIT_IEOF           2
 180 #define CHAN_OUTPUT_CLOSED              3
 181
 182 #define CHAN_CLOSE_SENT                 0x01
 183 #define CHAN_CLOSE_RCVD                 0x02
 184 #define CHAN_EOF_SENT                   0x04
 185 #define CHAN_EOF_RCVD                   0x08
 186 #define CHAN_LOCAL                      0x10
 187
 188 #define CHAN_RBUF       16*1024
 189
 190 /* check whether 'efd' is still in use */
 191 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 192         (compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
 193         (c->efd != -1 || \
 194         buffer_len(&c->extended) > 0))
 195 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 196         (compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
 197         c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
 198         buffer_len(&c->extended) > 0))
 199
 200 /* channel management */
 201
 202 Channel *channel_by_id(int);
 203 Channel *channel_lookup(int);
 204 Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
 205 void     channel_set_fds(int, int, int, int, int, int, int, u_int);
 206 void     channel_free(Channel *);
 207 void     channel_free_all(void);
 208 void     channel_stop_listening(void);
 209
 210 void     channel_send_open(int);
 211 void     channel_request_start(int, char *, int);
 212 void     channel_register_cleanup(int, channel_callback_fn *, int);
 213 void     channel_register_open_confirm(int, channel_open_fn *, void *);
 214 void     channel_register_filter(int, channel_infilter_fn *,
 215     channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
 216 void     channel_register_status_confirm(int, channel_confirm_cb *,
 217     channel_confirm_abandon_cb *, void *);
 218 void     channel_cancel_cleanup(int);
 219 int      channel_close_fd(int *);
 220 void     channel_send_window_changes(void);
 221
 222 /* protocol handler */
 223
 224 void     channel_input_close(int, u_int32_t, void *);
 225 void     channel_input_close_confirmation(int, u_int32_t, void *);
 226 void     channel_input_data(int, u_int32_t, void *);
 227 void     channel_input_extended_data(int, u_int32_t, void *);
 228 void     channel_input_ieof(int, u_int32_t, void *);
 229 void     channel_input_oclose(int, u_int32_t, void *);
 230 void     channel_input_open_confirmation(int, u_int32_t, void *);
 231 void     channel_input_open_failure(int, u_int32_t, void *);
 232 void     channel_input_port_open(int, u_int32_t, void *);
 233 void     channel_input_window_adjust(int, u_int32_t, void *);
 234 void     channel_input_status_confirm(int, u_int32_t, void *);
 235
 236 /* file descriptor handling (read/write) */
 237
 238 void     channel_prepare_select(fd_set **, fd_set **, int *, u_int*, int);
 239 void     channel_after_select(fd_set *, fd_set *);
 240 void     channel_output_poll(void);
 241
 242 int      channel_not_very_much_buffered_data(void);
 243 void     channel_close_all(void);
 244 int      channel_still_open(void);
 245 char    *channel_open_message(void);
 246 int      channel_find_open(void);
 247
 248 /* tcp forwarding */
 249 void     channel_set_af(int af);
 250 void     channel_permit_all_opens(void);
 251 void     channel_add_permitted_opens(char *, int);
 252 int      channel_add_adm_permitted_opens(char *, int);
 253 void     channel_clear_permitted_opens(void);
 254 void     channel_clear_adm_permitted_opens(void);
 255 void     channel_print_adm_permitted_opens(void);
 256 int      channel_input_port_forward_request(int, int);
 257 Channel *channel_connect_to(const char *, u_short, char *, char *);
 258 Channel *channel_connect_stdio_fwd(const char*, u_short, int, int);
 259 Channel *channel_connect_by_listen_address(u_short, char *, char *);
 260 int      channel_request_remote_forwarding(const char *, u_short,
 261              const char *, u_short);
 262 int      channel_setup_local_fwd_listener(const char *, u_short,
 263              const char *, u_short, int);
 264 void     channel_request_rforward_cancel(const char *host, u_short port);
 265 int      channel_setup_remote_fwd_listener(const char *, u_short, int *, int);
 266 int      channel_cancel_rport_listener(const char *, u_short);
 267
 268 /* x11 forwarding */
 269
 270 int      x11_connect_display(void);
 271 int      x11_create_display_inet(int, int, int, u_int *, int **);
 272 void     x11_input_open(int, u_int32_t, void *);
 273 void     x11_request_forwarding_with_spoofing(int, const char *, const char *,
 274              const char *);
 275 void     deny_input_open(int, u_int32_t, void *);
 276
 277 /* agent forwarding */
 278
 279 void     auth_request_forwarding(void);
 280
 281 /* channel close */
 282
 283 int      chan_is_dead(Channel *, int);
 284 void     chan_mark_dead(Channel *);
 285
 286 /* channel events */
 287
 288 void     chan_rcvd_oclose(Channel *);
 289 void     chan_rcvd_eow(Channel *);      /* SSH2-only */
 290 void     chan_read_failed(Channel *);
 291 void     chan_ibuf_empty(Channel *);
 292
 293 void     chan_rcvd_ieof(Channel *);
 294 void     chan_write_failed(Channel *);
 295 void     chan_obuf_empty(Channel *);
 296
 297 #endif