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Annotation of src/usr.bin/ssh/channels.h, Revision 1.131

1.131   ! djm         1: /* $OpenBSD: channels.h,v 1.130 2017/09/21 19:16:53 markus Exp $ */
1.65      stevesk     2:
1.17      deraadt     3: /*
1.19      markus      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: /*
1.59      markus     15:  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
1.17      deraadt    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:  */
1.2       markus     37:
1.35      markus     38: #ifndef CHANNEL_H
                     39: #define CHANNEL_H
1.28      markus     40:
1.1       markus     41: /* Definitions for channel types. */
1.6       markus     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_LARVAL             10      /* larval session */
1.23      markus     50: #define SSH_CHANNEL_RPORT_LISTENER     11      /* Listening to a R-style port  */
1.24      markus     51: #define SSH_CHANNEL_CONNECTING         12
1.30      markus     52: #define SSH_CHANNEL_DYNAMIC            13
1.33      markus     53: #define SSH_CHANNEL_ZOMBIE             14      /* Almost dead. */
1.103     djm        54: #define SSH_CHANNEL_MUX_LISTENER       15      /* Listener for mux conn. */
                     55: #define SSH_CHANNEL_MUX_CLIENT         16      /* Conn. to mux slave */
1.113     dtucker    56: #define SSH_CHANNEL_ABANDONED          17      /* Abandoned session, eg mux */
1.115     millert    57: #define SSH_CHANNEL_UNIX_LISTENER      18      /* Listening on a domain socket. */
                     58: #define SSH_CHANNEL_RUNIX_LISTENER     19      /* Listening to a R-style domain socket. */
1.119     markus     59: #define SSH_CHANNEL_MUX_PROXY          20      /* proxy channel for mux-slave */
1.130     markus     60: #define SSH_CHANNEL_RDYNAMIC_OPEN      21      /* reverse SOCKS, parsing request */
                     61: #define SSH_CHANNEL_RDYNAMIC_FINISH    22      /* reverse SOCKS, finishing connect */
                     62: #define SSH_CHANNEL_MAX_TYPE           23
1.1       markus     63:
1.107     markus     64: #define CHANNEL_CANCEL_PORT_STATIC     -1
                     65:
1.131   ! djm        66: /* TCP forwarding */
        !            67: #define FORWARD_DENY           0
        !            68: #define FORWARD_REMOTE         (1)
        !            69: #define FORWARD_LOCAL          (1<<1)
        !            70: #define FORWARD_ALLOW          (FORWARD_REMOTE|FORWARD_LOCAL)
        !            71:
        !            72: #define FORWARD_ADM            0x100
        !            73: #define FORWARD_USER           0x101
        !            74:
1.126     markus     75: struct ssh;
1.16      markus     76: struct Channel;
                     77: typedef struct Channel Channel;
1.128     djm        78: struct fwd_perm_list;
1.16      markus     79:
1.128     djm        80: typedef void channel_open_fn(struct ssh *, int, int, void *);
                     81: typedef void channel_callback_fn(struct ssh *, int, void *);
                     82: typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int);
                     83: typedef void channel_filter_cleanup_fn(struct ssh *, int, void *);
                     84: typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *,
                     85:     u_char **, size_t *);
1.1       markus     86:
1.90      djm        87: /* Channel success/failure callbacks */
1.128     djm        88: typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *);
                     89: typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *);
1.90      djm        90: struct channel_confirm {
                     91:        TAILQ_ENTRY(channel_confirm) entry;
                     92:        channel_confirm_cb *cb;
                     93:        channel_confirm_abandon_cb *abandon_cb;
                     94:        void *ctx;
                     95: };
                     96: TAILQ_HEAD(channel_confirms, channel_confirm);
                     97:
1.91      djm        98: /* Context for non-blocking connects */
                     99: struct channel_connect {
                    100:        char *host;
                    101:        int port;
                    102:        struct addrinfo *ai, *aitop;
                    103: };
                    104:
1.103     djm       105: /* Callbacks for mux channels back into client-specific code */
1.128     djm       106: typedef int mux_callback_fn(struct ssh *, struct Channel *);
1.103     djm       107:
1.16      markus    108: struct Channel {
1.5       deraadt   109:        int     type;           /* channel type/state */
                    110:        int     self;           /* my own channel identifier */
1.129     djm       111:        uint32_t remote_id;     /* channel identifier for remote peer */
                    112:        int     have_remote_id; /* non-zero if remote_id is valid */
                    113:
1.57      markus    114:        u_int   istate;         /* input from channel (state of receive half) */
                    115:        u_int   ostate;         /* output to channel  (state of transmit half) */
1.8       markus    116:        int     flags;          /* close sent/rcvd */
1.7       markus    117:        int     rfd;            /* read fd */
                    118:        int     wfd;            /* write fd */
                    119:        int     efd;            /* extended fd */
                    120:        int     sock;           /* sock fd */
1.103     djm       121:        int     ctl_chan;       /* control channel (multiplexed connections) */
1.27      markus    122:        int     isatty;         /* rfd is a tty */
1.75      djm       123:        int     client_tty;     /* (client) TTY has been requested */
1.48      markus    124:        int     force_drain;    /* force close on iEOF */
1.111     djm       125:        time_t  notbefore;      /* Pause IO until deadline (time_t) */
1.100     markus    126:        int     delayed;        /* post-select handlers for newly created
                    127:                                 * channels are delayed until the first call
1.117     djm       128:                                 * to a matching pre-select handler.
1.100     markus    129:                                 * this way post-select handlers are not
1.112     dtucker   130:                                 * accidentally called if a FD gets reused */
1.128     djm       131:        struct sshbuf *input;   /* data read from socket, to be sent over
1.5       deraadt   132:                                 * encrypted connection */
1.128     djm       133:        struct sshbuf *output;  /* data received over encrypted connection for
1.5       deraadt   134:                                 * send on socket */
1.128     djm       135:        struct sshbuf *extended;
                    136:
1.97      djm       137:        char    *path;
1.32      markus    138:                /* path for unix domain sockets, or host name for forwards */
1.5       deraadt   139:        int     listening_port; /* port being listened for forwards */
1.106     djm       140:        char   *listening_addr; /* addr being listened for forwards */
1.5       deraadt   141:        int     host_port;      /* remote port to connect for forwards */
                    142:        char   *remote_name;    /* remote hostname */
1.7       markus    143:
1.70      markus    144:        u_int   remote_window;
                    145:        u_int   remote_maxpacket;
                    146:        u_int   local_window;
                    147:        u_int   local_window_max;
                    148:        u_int   local_consumed;
                    149:        u_int   local_maxpacket;
1.7       markus    150:        int     extended_usage;
1.54      markus    151:        int     single_connection;
1.7       markus    152:
                    153:        char   *ctype;          /* type */
                    154:
1.11      markus    155:        /* callback */
1.104     djm       156:        channel_open_fn         *open_confirm;
1.90      djm       157:        void                    *open_confirm_ctx;
1.44      markus    158:        channel_callback_fn     *detach_user;
1.80      djm       159:        int                     detach_close;
1.90      djm       160:        struct channel_confirms status_confirms;
1.15      markus    161:
                    162:        /* filter */
1.83      reyk      163:        channel_infilter_fn     *input_filter;
                    164:        channel_outfilter_fn    *output_filter;
1.94      djm       165:        void                    *filter_ctx;
1.95      djm       166:        channel_filter_cleanup_fn *filter_cleanup;
1.81      reyk      167:
1.91      djm       168:        /* keep boundaries */
                    169:        int                     datagram;
                    170:
                    171:        /* non-blocking connect */
1.128     djm       172:        /* XXX make this a pointer so the structure can be opaque */
1.91      djm       173:        struct channel_connect  connect_ctx;
1.103     djm       174:
                    175:        /* multiplexing protocol hook, called for each packet received */
                    176:        mux_callback_fn         *mux_rcb;
                    177:        void                    *mux_ctx;
1.104     djm       178:        int                     mux_pause;
1.119     markus    179:        int                     mux_downstream_id;
1.16      markus    180: };
1.7       markus    181:
                    182: #define CHAN_EXTENDED_IGNORE           0
                    183: #define CHAN_EXTENDED_READ             1
                    184: #define CHAN_EXTENDED_WRITE            2
1.18      markus    185:
                    186: /* default window/packet sizes for tcp/x11-fwd-channel */
1.64      markus    187: #define CHAN_SES_PACKET_DEFAULT        (32*1024)
1.89      markus    188: #define CHAN_SES_WINDOW_DEFAULT        (64*CHAN_SES_PACKET_DEFAULT)
1.64      markus    189: #define CHAN_TCP_PACKET_DEFAULT        (32*1024)
1.89      markus    190: #define CHAN_TCP_WINDOW_DEFAULT        (64*CHAN_TCP_PACKET_DEFAULT)
1.64      markus    191: #define CHAN_X11_PACKET_DEFAULT        (16*1024)
                    192: #define CHAN_X11_WINDOW_DEFAULT        (4*CHAN_X11_PACKET_DEFAULT)
1.18      markus    193:
1.35      markus    194: /* possible input states */
1.57      markus    195: #define CHAN_INPUT_OPEN                        0
                    196: #define CHAN_INPUT_WAIT_DRAIN          1
                    197: #define CHAN_INPUT_WAIT_OCLOSE         2
                    198: #define CHAN_INPUT_CLOSED              3
1.35      markus    199:
                    200: /* possible output states */
1.57      markus    201: #define CHAN_OUTPUT_OPEN               0
                    202: #define CHAN_OUTPUT_WAIT_DRAIN         1
                    203: #define CHAN_OUTPUT_WAIT_IEOF          2
                    204: #define CHAN_OUTPUT_CLOSED             3
1.7       markus    205:
1.35      markus    206: #define CHAN_CLOSE_SENT                        0x01
                    207: #define CHAN_CLOSE_RCVD                        0x02
1.66      markus    208: #define CHAN_EOF_SENT                  0x04
                    209: #define CHAN_EOF_RCVD                  0x08
1.103     djm       210: #define CHAN_LOCAL                     0x10
1.66      markus    211:
1.128     djm       212: /* Read buffer size */
                    213: #define CHAN_RBUF      (16*1024)
                    214:
                    215: /* Hard limit on number of channels */
                    216: #define CHANNELS_MAX_CHANNELS  (16*1024)
1.83      reyk      217:
1.66      markus    218: /* check whether 'efd' is still in use */
                    219: #define CHANNEL_EFD_INPUT_ACTIVE(c) \
1.122     djm       220:        (c->extended_usage == CHAN_EXTENDED_READ && \
1.66      markus    221:        (c->efd != -1 || \
1.128     djm       222:        sshbuf_len(c->extended) > 0))
1.66      markus    223: #define CHANNEL_EFD_OUTPUT_ACTIVE(c) \
1.122     djm       224:        (c->extended_usage == CHAN_EXTENDED_WRITE && \
1.78      markus    225:        c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \
1.128     djm       226:        sshbuf_len(c->extended) > 0))
                    227:
                    228: /* Add channel management structures to SSH transport instance */
                    229: void channel_init_channels(struct ssh *ssh);
1.35      markus    230:
                    231: /* channel management */
                    232:
1.128     djm       233: Channel        *channel_by_id(struct ssh *, int);
1.129     djm       234: Channel        *channel_by_remote_id(struct ssh *, u_int);
1.128     djm       235: Channel        *channel_lookup(struct ssh *, int);
                    236: Channel *channel_new(struct ssh *, char *, int, int, int, int,
                    237:            u_int, u_int, int, char *, int);
                    238: void    channel_set_fds(struct ssh *, int, int, int, int, int,
                    239:            int, int, u_int);
                    240: void    channel_free(struct ssh *, Channel *);
                    241: void    channel_free_all(struct ssh *);
                    242: void    channel_stop_listening(struct ssh *);
                    243:
                    244: void    channel_send_open(struct ssh *, int);
                    245: void    channel_request_start(struct ssh *, int, char *, int);
                    246: void    channel_register_cleanup(struct ssh *, int,
                    247:            channel_callback_fn *, int);
                    248: void    channel_register_open_confirm(struct ssh *, int,
                    249:            channel_open_fn *, void *);
                    250: void    channel_register_filter(struct ssh *, int, channel_infilter_fn *,
                    251:            channel_outfilter_fn *, channel_filter_cleanup_fn *, void *);
                    252: void    channel_register_status_confirm(struct ssh *, int,
                    253:            channel_confirm_cb *, channel_confirm_abandon_cb *, void *);
                    254: void    channel_cancel_cleanup(struct ssh *, int);
                    255: int     channel_close_fd(struct ssh *, int *);
                    256: void    channel_send_window_changes(struct ssh *);
1.119     markus    257:
                    258: /* mux proxy support */
                    259:
1.128     djm       260: int     channel_proxy_downstream(struct ssh *, Channel *mc);
1.126     markus    261: int     channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *);
1.22      markus    262:
1.35      markus    263: /* protocol handler */
1.7       markus    264:
1.126     markus    265: int     channel_input_data(int, u_int32_t, struct ssh *);
                    266: int     channel_input_extended_data(int, u_int32_t, struct ssh *);
                    267: int     channel_input_ieof(int, u_int32_t, struct ssh *);
                    268: int     channel_input_oclose(int, u_int32_t, struct ssh *);
                    269: int     channel_input_open_confirmation(int, u_int32_t, struct ssh *);
                    270: int     channel_input_open_failure(int, u_int32_t, struct ssh *);
                    271: int     channel_input_port_open(int, u_int32_t, struct ssh *);
                    272: int     channel_input_window_adjust(int, u_int32_t, struct ssh *);
                    273: int     channel_input_status_confirm(int, u_int32_t, struct ssh *);
1.7       markus    274:
1.35      markus    275: /* file descriptor handling (read/write) */
1.7       markus    276:
1.127     djm       277: void    channel_prepare_select(struct ssh *, fd_set **, fd_set **, int *,
                    278:             u_int*, time_t*);
                    279: void     channel_after_select(struct ssh *, fd_set *, fd_set *);
1.128     djm       280: void     channel_output_poll(struct ssh *);
1.42      markus    281:
1.128     djm       282: int      channel_not_very_much_buffered_data(struct ssh *);
                    283: void     channel_close_all(struct ssh *);
                    284: int      channel_still_open(struct ssh *);
                    285: char   *channel_open_message(struct ssh *);
                    286: int     channel_find_open(struct ssh *);
1.7       markus    287:
1.47      markus    288: /* tcp forwarding */
1.115     millert   289: struct Forward;
                    290: struct ForwardOptions;
1.128     djm       291: void    channel_set_af(struct ssh *, int af);
1.131   ! djm       292: void     channel_permit_all(struct ssh *, int);
        !           293: void    channel_add_permission(struct ssh *, int, int, char *, int);
        !           294: void    channel_clear_permission(struct ssh *, int, int);
        !           295: void    channel_disable_admin(struct ssh *, int);
        !           296: void    channel_update_permission(struct ssh *, int, int);
1.128     djm       297: Channel        *channel_connect_to_port(struct ssh *, const char *, u_short,
                    298:            char *, char *, int *, const char **);
                    299: Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *);
                    300: Channel        *channel_connect_stdio_fwd(struct ssh *, const char*,
                    301:            u_short, int, int);
                    302: Channel        *channel_connect_by_listen_address(struct ssh *, const char *,
                    303:            u_short, char *, char *);
                    304: Channel        *channel_connect_by_listen_path(struct ssh *, const char *,
                    305:            char *, char *);
                    306: int     channel_request_remote_forwarding(struct ssh *, struct Forward *);
                    307: int     channel_setup_local_fwd_listener(struct ssh *, struct Forward *,
                    308:            struct ForwardOptions *);
                    309: int     channel_request_rforward_cancel(struct ssh *, struct Forward *);
                    310: int     channel_setup_remote_fwd_listener(struct ssh *, struct Forward *,
                    311:            int *, struct ForwardOptions *);
                    312: int     channel_cancel_rport_listener(struct ssh *, struct Forward *);
                    313: int     channel_cancel_lport_listener(struct ssh *, struct Forward *,
                    314:            int, struct ForwardOptions *);
1.108     dtucker   315: int     permitopen_port(const char *);
1.7       markus    316:
1.35      markus    317: /* x11 forwarding */
1.7       markus    318:
1.128     djm       319: void    channel_set_x11_refuse_time(struct ssh *, u_int);
                    320: int     x11_connect_display(struct ssh *);
                    321: int     x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **);
                    322: void    x11_request_forwarding_with_spoofing(struct ssh *, int,
                    323:            const char *, const char *, const char *, int);
1.7       markus    324:
1.35      markus    325: /* channel close */
1.8       markus    326:
1.128     djm       327: int     chan_is_dead(struct ssh *, Channel *, int);
                    328: void    chan_mark_dead(struct ssh *, Channel *);
1.42      markus    329:
1.58      markus    330: /* channel events */
1.31      beck      331:
1.128     djm       332: void    chan_rcvd_oclose(struct ssh *, Channel *);
                    333: void    chan_rcvd_eow(struct ssh *, Channel *);
                    334: void    chan_read_failed(struct ssh *, Channel *);
                    335: void    chan_ibuf_empty(struct ssh *, Channel *);
                    336: void    chan_rcvd_ieof(struct ssh *, Channel *);
                    337: void    chan_write_failed(struct ssh *, Channel *);
                    338: void    chan_obuf_empty(struct ssh *, Channel *);
1.7       markus    339:
1.1       markus    340: #endif