channels.h

   1 /*      $OpenBSD: channels.h,v 1.76 2005/03/01 10:09:52 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 #include "buffer.h"
  42
  43 /* Definitions for channel types. */
  44 #define SSH_CHANNEL_X11_LISTENER        1       /* Listening for inet X11 conn. */
  45 #define SSH_CHANNEL_PORT_LISTENER       2       /* Listening on a port. */
  46 #define SSH_CHANNEL_OPENING             3       /* waiting for confirmation */
  47 #define SSH_CHANNEL_OPEN                4       /* normal open two-way channel */
  48 #define SSH_CHANNEL_CLOSED              5       /* waiting for close confirmation */
  49 #define SSH_CHANNEL_AUTH_SOCKET         6       /* authentication socket */
  50 #define SSH_CHANNEL_X11_OPEN            7       /* reading first X11 packet */
  51 #define SSH_CHANNEL_INPUT_DRAINING      8       /* sending remaining data to conn */
  52 #define SSH_CHANNEL_OUTPUT_DRAINING     9       /* sending remaining data to app */
  53 #define SSH_CHANNEL_LARVAL              10      /* larval session */
  54 #define SSH_CHANNEL_RPORT_LISTENER      11      /* Listening to a R-style port  */
  55 #define SSH_CHANNEL_CONNECTING          12
  56 #define SSH_CHANNEL_DYNAMIC             13
  57 #define SSH_CHANNEL_ZOMBIE              14      /* Almost dead. */
  58 #define SSH_CHANNEL_MAX_TYPE            15
  59
  60 #define SSH_CHANNEL_PATH_LEN            256
  61
  62 struct Channel;
  63 typedef struct Channel Channel;
  64
  65 typedef void channel_callback_fn(int, void *);
  66 typedef int channel_filter_fn(struct Channel *, char *, int);
  67
  68 struct Channel {
  69         int     type;           /* channel type/state */
  70         int     self;           /* my own channel identifier */
  71         int     remote_id;      /* channel identifier for remote peer */
  72         u_int   istate;         /* input from channel (state of receive half) */
  73         u_int   ostate;         /* output to channel  (state of transmit half) */
  74         int     flags;          /* close sent/rcvd */
  75         int     rfd;            /* read fd */
  76         int     wfd;            /* write fd */
  77         int     efd;            /* extended fd */
  78         int     sock;           /* sock fd */
  79         int     ctl_fd;         /* control fd (client sharing) */
  80         int     isatty;         /* rfd is a tty */
  81         int     wfd_isatty;     /* wfd is a tty */
  82         int     client_tty;     /* (client) TTY has been requested */
  83         int     force_drain;    /* force close on iEOF */
  84         int     delayed;                /* fdset hack */
  85         Buffer  input;          /* data read from socket, to be sent over
  86                                  * encrypted connection */
  87         Buffer  output;         /* data received over encrypted connection for
  88                                  * send on socket */
  89         Buffer  extended;
  90         char    path[SSH_CHANNEL_PATH_LEN];
  91                 /* path for unix domain sockets, or host name for forwards */
  92         int     listening_port; /* port being listened for forwards */
  93         int     host_port;      /* remote port to connect for forwards */
  94         char   *remote_name;    /* remote hostname */
  95
  96         u_int   remote_window;
  97         u_int   remote_maxpacket;
  98         u_int   local_window;
  99         u_int   local_window_max;
 100         u_int   local_consumed;
 101         u_int   local_maxpacket;
 102         int     extended_usage;
 103         int     single_connection;
 104
 105         char   *ctype;          /* type */
 106
 107         /* callback */
 108         channel_callback_fn     *confirm;
 109         channel_callback_fn     *detach_user;
 110         void                    *confirm_ctx;
 111
 112         /* filter */
 113         channel_filter_fn       *input_filter;
 114 };
 115
 116 #define CHAN_EXTENDED_IGNORE            0
 117 #define CHAN_EXTENDED_READ              1
 118 #define CHAN_EXTENDED_WRITE             2
 119
 120 /* default window/packet sizes for tcp/x11-fwd-channel */
 121 #define CHAN_SES_PACKET_DEFAULT (32*1024)
 122 #define CHAN_SES_WINDOW_DEFAULT (4*CHAN_SES_PACKET_DEFAULT)
 123 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
 124 #define CHAN_TCP_WINDOW_DEFAULT (4*CHAN_TCP_PACKET_DEFAULT)
 125 #define CHAN_X11_PACKET_DEFAULT (16*1024)
 126 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
 127
 128 /* possible input states */
 129 #define CHAN_INPUT_OPEN                 0
 130 #define CHAN_INPUT_WAIT_DRAIN           1
 131 #define CHAN_INPUT_WAIT_OCLOSE          2
 132 #define CHAN_INPUT_CLOSED               3
 133
 134 /* possible output states */
 135 #define CHAN_OUTPUT_OPEN                0
 136 #define CHAN_OUTPUT_WAIT_DRAIN          1
 137 #define CHAN_OUTPUT_WAIT_IEOF           2
 138 #define CHAN_OUTPUT_CLOSED              3
 139
 140 #define CHAN_CLOSE_SENT                 0x01
 141 #define CHAN_CLOSE_RCVD                 0x02
 142 #define CHAN_EOF_SENT                   0x04
 143 #define CHAN_EOF_RCVD                   0x08
 144
 145 /* check whether 'efd' is still in use */
 146 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 147         (compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
 148         (c->efd != -1 || \
 149         buffer_len(&c->extended) > 0))
 150 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 151         (compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
 152         ((c->efd != -1 && !(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD))) || \
 153         buffer_len(&c->extended) > 0))
 154
 155 /* channel management */
 156
 157 Channel *channel_lookup(int);
 158 Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
 159 void     channel_set_fds(int, int, int, int, int, int, u_int);
 160 void     channel_free(Channel *);
 161 void     channel_free_all(void);
 162 void     channel_stop_listening(void);
 163
 164 void     channel_send_open(int);
 165 void     channel_request_start(int, char *, int);
 166 void     channel_register_cleanup(int, channel_callback_fn *);
 167 void     channel_register_confirm(int, channel_callback_fn *, void *);
 168 void     channel_register_filter(int, channel_filter_fn *);
 169 void     channel_cancel_cleanup(int);
 170 int      channel_close_fd(int *);
 171 void     channel_send_window_changes(void);
 172
 173 /* protocol handler */
 174
 175 void     channel_input_close(int, u_int32_t, void *);
 176 void     channel_input_close_confirmation(int, u_int32_t, void *);
 177 void     channel_input_data(int, u_int32_t, void *);
 178 void     channel_input_extended_data(int, u_int32_t, void *);
 179 void     channel_input_ieof(int, u_int32_t, void *);
 180 void     channel_input_oclose(int, u_int32_t, void *);
 181 void     channel_input_open_confirmation(int, u_int32_t, void *);
 182 void     channel_input_open_failure(int, u_int32_t, void *);
 183 void     channel_input_port_open(int, u_int32_t, void *);
 184 void     channel_input_window_adjust(int, u_int32_t, void *);
 185
 186 /* file descriptor handling (read/write) */
 187
 188 void     channel_prepare_select(fd_set **, fd_set **, int *, u_int*, int);
 189 void     channel_after_select(fd_set *, fd_set *);
 190 void     channel_output_poll(void);
 191
 192 int      channel_not_very_much_buffered_data(void);
 193 void     channel_close_all(void);
 194 int      channel_still_open(void);
 195 char    *channel_open_message(void);
 196 int      channel_find_open(void);
 197
 198 /* tcp forwarding */
 199 void     channel_set_af(int af);
 200 void     channel_permit_all_opens(void);
 201 void     channel_add_permitted_opens(char *, int);
 202 void     channel_clear_permitted_opens(void);
 203 void     channel_input_port_forward_request(int, int);
 204 int      channel_connect_to(const char *, u_short);
 205 int      channel_connect_by_listen_address(u_short);
 206 void     channel_request_remote_forwarding(const char *, u_short,
 207              const char *, u_short);
 208 int      channel_setup_local_fwd_listener(const char *, u_short,
 209              const char *, u_short, int);
 210 void     channel_request_rforward_cancel(const char *host, u_short port);
 211 int      channel_setup_remote_fwd_listener(const char *, u_short, int);
 212 int      channel_cancel_rport_listener(const char *, u_short);
 213
 214 /* x11 forwarding */
 215
 216 int      x11_connect_display(void);
 217 int      x11_create_display_inet(int, int, int, u_int *);
 218 void     x11_input_open(int, u_int32_t, void *);
 219 void     x11_request_forwarding_with_spoofing(int, const char *, const char *);
 220 void     deny_input_open(int, u_int32_t, void *);
 221
 222 /* agent forwarding */
 223
 224 void     auth_request_forwarding(void);
 225
 226 /* channel close */
 227
 228 int      chan_is_dead(Channel *, int);
 229 void     chan_mark_dead(Channel *);
 230
 231 /* channel events */
 232
 233 void     chan_rcvd_oclose(Channel *);
 234 void     chan_read_failed(Channel *);
 235 void     chan_ibuf_empty(Channel *);
 236
 237 void     chan_rcvd_ieof(Channel *);
 238 void     chan_write_failed(Channel *);
 239 void     chan_obuf_empty(Channel *);
 240
 241 #endif