channels.h

   1 /* $OpenBSD: channels.h,v 1.88 2006/08/03 03:34:42 deraadt 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_MAX_TYPE            15
  57
  58 #define SSH_CHANNEL_PATH_LEN            256
  59
  60 struct Channel;
  61 typedef struct Channel Channel;
  62
  63 typedef void channel_callback_fn(int, void *);
  64 typedef int channel_infilter_fn(struct Channel *, char *, int);
  65 typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
  66
  67 struct Channel {
  68         int     type;           /* channel type/state */
  69         int     self;           /* my own channel identifier */
  70         int     remote_id;      /* channel identifier for remote peer */
  71         u_int   istate;         /* input from channel (state of receive half) */
  72         u_int   ostate;         /* output to channel  (state of transmit half) */
  73         int     flags;          /* close sent/rcvd */
  74         int     rfd;            /* read fd */
  75         int     wfd;            /* write fd */
  76         int     efd;            /* extended fd */
  77         int     sock;           /* sock fd */
  78         int     ctl_fd;         /* control fd (client sharing) */
  79         int     isatty;         /* rfd is a tty */
  80         int     wfd_isatty;     /* wfd is a tty */
  81         int     client_tty;     /* (client) TTY has been requested */
  82         int     force_drain;    /* force close on iEOF */
  83         int     delayed;                /* fdset hack */
  84         Buffer  input;          /* data read from socket, to be sent over
  85                                  * encrypted connection */
  86         Buffer  output;         /* data received over encrypted connection for
  87                                  * send on socket */
  88         Buffer  extended;
  89         char    path[SSH_CHANNEL_PATH_LEN];
  90                 /* path for unix domain sockets, or host name for forwards */
  91         int     listening_port; /* port being listened for forwards */
  92         int     host_port;      /* remote port to connect for forwards */
  93         char   *remote_name;    /* remote hostname */
  94
  95         u_int   remote_window;
  96         u_int   remote_maxpacket;
  97         u_int   local_window;
  98         u_int   local_window_max;
  99         u_int   local_consumed;
 100         u_int   local_maxpacket;
 101         int     extended_usage;
 102         int     single_connection;
 103
 104         char   *ctype;          /* type */
 105
 106         /* callback */
 107         channel_callback_fn     *confirm;
 108         void                    *confirm_ctx;
 109         channel_callback_fn     *detach_user;
 110         int                     detach_close;
 111
 112         /* filter */
 113         channel_infilter_fn     *input_filter;
 114         channel_outfilter_fn    *output_filter;
 115
 116         int     datagram;       /* keep boundaries */
 117 };
 118
 119 #define CHAN_EXTENDED_IGNORE            0
 120 #define CHAN_EXTENDED_READ              1
 121 #define CHAN_EXTENDED_WRITE             2
 122
 123 /* default window/packet sizes for tcp/x11-fwd-channel */
 124 #define CHAN_SES_PACKET_DEFAULT (32*1024)
 125 #define CHAN_SES_WINDOW_DEFAULT (4*CHAN_SES_PACKET_DEFAULT)
 126 #define CHAN_TCP_PACKET_DEFAULT (32*1024)
 127 #define CHAN_TCP_WINDOW_DEFAULT (4*CHAN_TCP_PACKET_DEFAULT)
 128 #define CHAN_X11_PACKET_DEFAULT (16*1024)
 129 #define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT)
 130
 131 /* possible input states */
 132 #define CHAN_INPUT_OPEN                 0
 133 #define CHAN_INPUT_WAIT_DRAIN           1
 134 #define CHAN_INPUT_WAIT_OCLOSE          2
 135 #define CHAN_INPUT_CLOSED               3
 136
 137 /* possible output states */
 138 #define CHAN_OUTPUT_OPEN                0
 139 #define CHAN_OUTPUT_WAIT_DRAIN          1
 140 #define CHAN_OUTPUT_WAIT_IEOF           2
 141 #define CHAN_OUTPUT_CLOSED              3
 142
 143 #define CHAN_CLOSE_SENT                 0x01
 144 #define CHAN_CLOSE_RCVD                 0x02
 145 #define CHAN_EOF_SENT                   0x04
 146 #define CHAN_EOF_RCVD                   0x08
 147
 148 #define CHAN_RBUF       16*1024
 149
 150 /* check whether 'efd' is still in use */
 151 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
 152         (compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
 153         (c->efd != -1 || \
 154         buffer_len(&c->extended) > 0))
 155 #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
 156         (compat20 && c->extended_usage == CHAN_EXTENDED_WRITE && \
 157         c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
 158         buffer_len(&c->extended) > 0))
 159
 160 /* channel management */
 161
 162 Channel *channel_by_id(int);
 163 Channel *channel_lookup(int);
 164 Channel *channel_new(char *, int, int, int, int, u_int, u_int, int, char *, int);
 165 void     channel_set_fds(int, int, int, int, int, int, u_int);
 166 void     channel_free(Channel *);
 167 void     channel_free_all(void);
 168 void     channel_stop_listening(void);
 169
 170 void     channel_send_open(int);
 171 void     channel_request_start(int, char *, int);
 172 void     channel_register_cleanup(int, channel_callback_fn *, int);
 173 void     channel_register_confirm(int, channel_callback_fn *, void *);
 174 void     channel_register_filter(int, channel_infilter_fn *, channel_outfilter_fn *);
 175 void     channel_cancel_cleanup(int);
 176 int      channel_close_fd(int *);
 177 void     channel_send_window_changes(void);
 178
 179 /* protocol handler */
 180
 181 void     channel_input_close(int, u_int32_t, void *);
 182 void     channel_input_close_confirmation(int, u_int32_t, void *);
 183 void     channel_input_data(int, u_int32_t, void *);
 184 void     channel_input_extended_data(int, u_int32_t, void *);
 185 void     channel_input_ieof(int, u_int32_t, void *);
 186 void     channel_input_oclose(int, u_int32_t, void *);
 187 void     channel_input_open_confirmation(int, u_int32_t, void *);
 188 void     channel_input_open_failure(int, u_int32_t, void *);
 189 void     channel_input_port_open(int, u_int32_t, void *);
 190 void     channel_input_window_adjust(int, u_int32_t, void *);
 191
 192 /* file descriptor handling (read/write) */
 193
 194 void     channel_prepare_select(fd_set **, fd_set **, int *, u_int*, int);
 195 void     channel_after_select(fd_set *, fd_set *);
 196 void     channel_output_poll(void);
 197
 198 int      channel_not_very_much_buffered_data(void);
 199 void     channel_close_all(void);
 200 int      channel_still_open(void);
 201 char    *channel_open_message(void);
 202 int      channel_find_open(void);
 203
 204 /* tcp forwarding */
 205 void     channel_set_af(int af);
 206 void     channel_permit_all_opens(void);
 207 void     channel_add_permitted_opens(char *, int);
 208 int      channel_add_adm_permitted_opens(char *, int);
 209 void     channel_clear_permitted_opens(void);
 210 void     channel_clear_adm_permitted_opens(void);
 211 int      channel_input_port_forward_request(int, int);
 212 int      channel_connect_to(const char *, u_short);
 213 int      channel_connect_by_listen_address(u_short);
 214 int      channel_request_remote_forwarding(const char *, u_short,
 215              const char *, u_short);
 216 int      channel_setup_local_fwd_listener(const char *, u_short,
 217              const char *, u_short, int);
 218 void     channel_request_rforward_cancel(const char *host, u_short port);
 219 int      channel_setup_remote_fwd_listener(const char *, u_short, int);
 220 int      channel_cancel_rport_listener(const char *, u_short);
 221
 222 /* x11 forwarding */
 223
 224 int      x11_connect_display(void);
 225 int      x11_create_display_inet(int, int, int, u_int *, int **);
 226 void     x11_input_open(int, u_int32_t, void *);
 227 void     x11_request_forwarding_with_spoofing(int, const char *, const char *,
 228             const char *);
 229 void     deny_input_open(int, u_int32_t, void *);
 230
 231 /* agent forwarding */
 232
 233 void     auth_request_forwarding(void);
 234
 235 /* channel close */
 236
 237 int      chan_is_dead(Channel *, int);
 238 void     chan_mark_dead(Channel *);
 239
 240 /* channel events */
 241
 242 void     chan_rcvd_oclose(Channel *);
 243 void     chan_read_failed(Channel *);
 244 void     chan_ibuf_empty(Channel *);
 245
 246 void     chan_rcvd_ieof(Channel *);
 247 void     chan_write_failed(Channel *);
 248 void     chan_obuf_empty(Channel *);
 249
 250 #endif