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Annotation of src/usr.bin/ssh/channels.h, Revision 1.25

1.17      deraadt     1: /*
1.19      markus      2:  * Author: Tatu Ylonen <ylo@cs.hut.fi>
                      3:  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                      4:  *                    All rights reserved
                      5:  *
                      6:  * As far as I am concerned, the code I have written for this software
                      7:  * can be used freely for any purpose.  Any derived versions of this
                      8:  * software must be clearly marked as such, and if the derived work is
                      9:  * incompatible with the protocol description in the RFC file, it must be
                     10:  * called by a name other than "ssh" or "Secure Shell".
                     11:  */
                     12: /*
1.17      deraadt    13:  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
                     14:  *
                     15:  * Redistribution and use in source and binary forms, with or without
                     16:  * modification, are permitted provided that the following conditions
                     17:  * are met:
                     18:  * 1. Redistributions of source code must retain the above copyright
                     19:  *    notice, this list of conditions and the following disclaimer.
                     20:  * 2. Redistributions in binary form must reproduce the above copyright
                     21:  *    notice, this list of conditions and the following disclaimer in the
                     22:  *    documentation and/or other materials provided with the distribution.
                     23:  *
                     24:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
                     25:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     26:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     27:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
                     28:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
                     29:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
                     30:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
                     31:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
                     32:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
                     33:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                     34:  */
1.25    ! markus     35: /* RCSID("$OpenBSD: channels.h,v 1.24 2000/12/05 20:34:10 markus Exp $"); */
1.2       markus     36:
1.1       markus     37: #ifndef CHANNELS_H
                     38: #define CHANNELS_H
                     39:
                     40: /* Definitions for channel types. */
1.6       markus     41: #define SSH_CHANNEL_FREE               0       /* This channel is free (unused). */
                     42: #define SSH_CHANNEL_X11_LISTENER       1       /* Listening for inet X11 conn. */
1.5       deraadt    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 */
1.6       markus     46: #define SSH_CHANNEL_CLOSED             5       /* waiting for close confirmation */
1.7       markus     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 */
1.23      markus     52: #define SSH_CHANNEL_RPORT_LISTENER     11      /* Listening to a R-style port  */
1.24      markus     53: #define SSH_CHANNEL_CONNECTING         12
                     54: #define SSH_CHANNEL_MAX_TYPE           13
1.1       markus     55:
1.6       markus     56: /*
                     57:  * Data structure for channel data.  This is iniailized in channel_allocate
                     58:  * and cleared in channel_free.
                     59:  */
1.16      markus     60: struct Channel;
                     61: typedef struct Channel Channel;
                     62:
1.7       markus     63: typedef void channel_callback_fn(int id, void *arg);
1.16      markus     64: typedef int channel_filter_fn(struct Channel *c, char *buf, int len);
1.1       markus     65:
1.16      markus     66: struct Channel {
1.5       deraadt    67:        int     type;           /* channel type/state */
                     68:        int     self;           /* my own channel identifier */
                     69:        int     remote_id;      /* channel identifier for remote peer */
                     70:        /* peer can be reached over encrypted connection, via packet-sent */
                     71:        int     istate;         /* input from channel (state of receive half) */
                     72:        int     ostate;         /* output to channel  (state of transmit half) */
1.8       markus     73:        int     flags;          /* close sent/rcvd */
1.7       markus     74:        int     rfd;            /* read fd */
                     75:        int     wfd;            /* write fd */
                     76:        int     efd;            /* extended fd */
                     77:        int     sock;           /* sock fd */
1.5       deraadt    78:        Buffer  input;          /* data read from socket, to be sent over
                     79:                                 * encrypted connection */
                     80:        Buffer  output;         /* data received over encrypted connection for
                     81:                                 * send on socket */
1.7       markus     82:        Buffer  extended;
1.5       deraadt    83:        char    path[200];      /* path for unix domain sockets, or host name
                     84:                                 * for forwards */
                     85:        int     listening_port; /* port being listened for forwards */
                     86:        int     host_port;      /* remote port to connect for forwards */
                     87:        char   *remote_name;    /* remote hostname */
1.7       markus     88:
                     89:        int     remote_window;
                     90:        int     remote_maxpacket;
                     91:        int     local_window;
                     92:        int     local_window_max;
                     93:        int     local_consumed;
                     94:        int     local_maxpacket;
                     95:        int     extended_usage;
                     96:
                     97:        char   *ctype;          /* type */
                     98:
1.11      markus     99:        /* callback */
1.7       markus    100:        channel_callback_fn     *cb_fn;
                    101:        void    *cb_arg;
                    102:        int     cb_event;
                    103:        channel_callback_fn     *dettach_user;
1.15      markus    104:
                    105:        /* filter */
                    106:        channel_filter_fn       *input_filter;
1.16      markus    107: };
1.7       markus    108:
                    109: #define CHAN_EXTENDED_IGNORE           0
                    110: #define CHAN_EXTENDED_READ             1
                    111: #define CHAN_EXTENDED_WRITE            2
1.18      markus    112:
                    113: /* default window/packet sizes for tcp/x11-fwd-channel */
                    114: #define CHAN_SES_WINDOW_DEFAULT        (32*1024)
                    115: #define CHAN_SES_PACKET_DEFAULT        (CHAN_SES_WINDOW_DEFAULT/2)
                    116: #define CHAN_TCP_WINDOW_DEFAULT        (32*1024)
                    117: #define CHAN_TCP_PACKET_DEFAULT        (CHAN_TCP_WINDOW_DEFAULT/2)
                    118: #define CHAN_X11_WINDOW_DEFAULT        (4*1024)
                    119: #define CHAN_X11_PACKET_DEFAULT        (CHAN_X11_WINDOW_DEFAULT/2)
                    120:
1.7       markus    121:
                    122: void   channel_open(int id);
1.8       markus    123: void   channel_request(int id, char *service, int wantconfirm);
                    124: void   channel_request_start(int id, char *service, int wantconfirm);
                    125: void   channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
                    126: void   channel_register_cleanup(int id, channel_callback_fn *fn);
1.15      markus    127: void   channel_register_filter(int id, channel_filter_fn *fn);
1.8       markus    128: void   channel_cancel_cleanup(int id);
1.7       markus    129: Channel        *channel_lookup(int id);
                    130:
                    131: int
                    132: channel_new(char *ctype, int type, int rfd, int wfd, int efd,
1.21      markus    133:     int window, int maxpack, int extended_usage, char *remote_name,
                    134:     int nonblock);
                    135: void
                    136: channel_set_fds(int id, int rfd, int wfd, int efd,
                    137:     int extusage, int nonblock);
1.22      markus    138:
                    139: void   deny_input_open(int type, int plen, void *ctxt);
1.7       markus    140:
1.20      markus    141: void   channel_input_channel_request(int type, int plen, void *ctxt);
                    142: void   channel_input_close(int type, int plen, void *ctxt);
                    143: void   channel_input_close_confirmation(int type, int plen, void *ctxt);
                    144: void   channel_input_data(int type, int plen, void *ctxt);
                    145: void   channel_input_extended_data(int type, int plen, void *ctxt);
                    146: void   channel_input_ieof(int type, int plen, void *ctxt);
                    147: void   channel_input_oclose(int type, int plen, void *ctxt);
                    148: void   channel_input_open_confirmation(int type, int plen, void *ctxt);
                    149: void   channel_input_open_failure(int type, int plen, void *ctxt);
                    150: void   channel_input_port_open(int type, int plen, void *ctxt);
                    151: void   channel_input_window_adjust(int type, int plen, void *ctxt);
1.7       markus    152:
                    153: /* Sets specific protocol options. */
                    154: void    channel_set_options(int hostname_in_open);
                    155:
                    156: /*
                    157:  * Allocate a new channel object and set its type and socket.  Remote_name
                    158:  * must have been allocated with xmalloc; this will free it when the channel
                    159:  * is freed.
                    160:  */
                    161: int     channel_allocate(int type, int sock, char *remote_name);
                    162:
                    163: /* Free the channel and close its socket. */
                    164: void    channel_free(int channel);
                    165:
1.25    ! markus    166: /*
        !           167:  * Allocate/update select bitmasks and add any bits relevant to channels in
        !           168:  * select bitmasks.
        !           169:  */
        !           170: void
        !           171: channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp);
1.7       markus    172:
                    173: /*
                    174:  * After select, perform any appropriate operations for channels which have
                    175:  * events pending.
                    176:  */
                    177: void    channel_after_select(fd_set * readset, fd_set * writeset);
                    178:
                    179: /* If there is data to send to the connection, send some of it now. */
                    180: void    channel_output_poll(void);
                    181:
                    182: /* Returns true if no channel has too much buffered data. */
                    183: int     channel_not_very_much_buffered_data(void);
                    184:
                    185: /* This closes any sockets that are listening for connections; this removes
                    186:    any unix domain sockets. */
                    187: void    channel_stop_listening(void);
                    188:
                    189: /*
                    190:  * Closes the sockets of all channels.  This is used to close extra file
                    191:  * descriptors after a fork.
                    192:  */
                    193: void    channel_close_all(void);
                    194:
                    195: /* Returns true if there is still an open channel over the connection. */
                    196: int     channel_still_open(void);
                    197:
                    198: /*
                    199:  * Returns a string containing a list of all open channels.  The list is
                    200:  * suitable for displaying to the user.  It uses crlf instead of newlines.
                    201:  * The caller should free the string with xfree.
                    202:  */
                    203: char   *channel_open_message(void);
                    204:
                    205: /*
                    206:  * Initiate forwarding of connections to local port "port" through the secure
1.23      markus    207:  * channel to host:port from remote side.
1.7       markus    208:  */
1.9       markus    209: void
1.23      markus    210: channel_request_local_forwarding(u_short listen_port,
                    211:     const char *host_to_connect, u_short port_to_connect, int gateway_ports);
                    212: void
                    213: channel_request_forwarding(const char *listen_address, u_short listen_port,
                    214:     const char *host_to_connect, u_short port_to_connect, int gateway_ports,
                    215:     int remote_fwd);
1.7       markus    216:
                    217: /*
                    218:  * Initiate forwarding of connections to port "port" on remote host through
                    219:  * the secure channel to host:port from local side.  This never returns if
                    220:  * there was an error.  This registers that open requests for that port are
                    221:  * permitted.
                    222:  */
1.9       markus    223: void
1.7       markus    224: channel_request_remote_forwarding(u_short port, const char *host,
                    225:     u_short remote_port);
                    226:
                    227: /*
                    228:  * Permits opening to any host/port in SSH_MSG_PORT_OPEN.  This is usually
                    229:  * called by the server, because the user could connect to any port anyway,
                    230:  * and the server has no way to know but to trust the client anyway.
                    231:  */
                    232: void    channel_permit_all_opens(void);
                    233:
                    234: /*
                    235:  * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
                    236:  * listening for the port, and sends back a success reply (or disconnect
                    237:  * message if there was an error).  This never returns if there was an error.
                    238:  */
1.12      markus    239: void    channel_input_port_forward_request(int is_root, int gateway_ports);
1.7       markus    240:
                    241: /*
                    242:  * Creates a port for X11 connections, and starts listening for it. Returns
                    243:  * the display name, or NULL if an error was encountered.
                    244:  */
                    245: char   *x11_create_display(int screen);
                    246:
                    247: /*
                    248:  * Creates an internet domain socket for listening for X11 connections.
                    249:  * Returns a suitable value for the DISPLAY variable, or NULL if an error
                    250:  * occurs.
                    251:  */
                    252: char   *x11_create_display_inet(int screen, int x11_display_offset);
                    253:
                    254: /*
                    255:  * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
                    256:  * the remote channel number.  We should do whatever we want, and respond
                    257:  * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
                    258:  */
1.20      markus    259: void    x11_input_open(int type, int plen, void *ctxt);
1.7       markus    260:
                    261: /*
                    262:  * Requests forwarding of X11 connections.  This should be called on the
                    263:  * client only.
                    264:  */
                    265: void    x11_request_forwarding(void);
                    266:
                    267: /*
                    268:  * Requests forwarding for X11 connections, with authentication spoofing.
                    269:  * This should be called in the client only.
                    270:  */
1.10      markus    271: void
                    272: x11_request_forwarding_with_spoofing(int client_session_id,
                    273:     const char *proto, const char *data);
1.7       markus    274:
                    275: /* Sends a message to the server to request authentication fd forwarding. */
                    276: void    auth_request_forwarding(void);
                    277:
                    278: /*
                    279:  * Returns the name of the forwarded authentication socket.  Returns NULL if
                    280:  * there is no forwarded authentication socket.  The returned value points to
                    281:  * a static buffer.
                    282:  */
                    283: char   *auth_get_socket_name(void);
                    284:
                    285: /*
1.13      markus    286:  * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
1.7       markus    287:  * This starts forwarding authentication requests.
                    288:  */
1.13      markus    289: int     auth_input_request_forwarding(struct passwd * pw);
1.7       markus    290:
                    291: /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
1.20      markus    292: void    auth_input_open_request(int type, int plen, void *ctxt);
1.8       markus    293:
                    294: /* XXX */
                    295: int    channel_connect_to(const char *host, u_short host_port);
1.23      markus    296: int    channel_connect_by_listen_adress(u_short listen_port);
1.10      markus    297: int    x11_connect_display(void);
1.7       markus    298:
1.1       markus    299: #endif