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Diffstat (limited to 'channels.h')
| -rw-r--r-- | channels.h | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/channels.h b/channels.h new file mode 100644 index 0000000..bb2650f --- /dev/null +++ b/channels.h @@ -0,0 +1,401 @@ +/* $OpenBSD: channels.h,v 1.154 2023/12/18 14:47:20 djm Exp $ */ + +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + */ +/* + * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef CHANNEL_H +#define CHANNEL_H + +/* Definitions for channel types. */ +#define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */ +#define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */ +#define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */ +#define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */ +#define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */ +#define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */ +#define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */ +#define SSH_CHANNEL_LARVAL 10 /* larval session */ +#define SSH_CHANNEL_RPORT_LISTENER 11 /* Listening to a R-style port */ +#define SSH_CHANNEL_CONNECTING 12 +#define SSH_CHANNEL_DYNAMIC 13 +#define SSH_CHANNEL_ZOMBIE 14 /* Almost dead. */ +#define SSH_CHANNEL_MUX_LISTENER 15 /* Listener for mux conn. */ +#define SSH_CHANNEL_MUX_CLIENT 16 /* Conn. to mux client */ +#define SSH_CHANNEL_ABANDONED 17 /* Abandoned session, eg mux */ +#define SSH_CHANNEL_UNIX_LISTENER 18 /* Listening on a domain socket. */ +#define SSH_CHANNEL_RUNIX_LISTENER 19 /* Listening to a R-style domain socket. */ +#define SSH_CHANNEL_MUX_PROXY 20 /* proxy channel for mux-client */ +#define SSH_CHANNEL_RDYNAMIC_OPEN 21 /* reverse SOCKS, parsing request */ +#define SSH_CHANNEL_RDYNAMIC_FINISH 22 /* reverse SOCKS, finishing connect */ +#define SSH_CHANNEL_MAX_TYPE 23 + +#define CHANNEL_CANCEL_PORT_STATIC -1 + +/* nonblocking flags for channel_new */ +#define CHANNEL_NONBLOCK_LEAVE 0 /* don't modify non-blocking state */ +#define CHANNEL_NONBLOCK_SET 1 /* set non-blocking state */ +#define CHANNEL_NONBLOCK_STDIO 2 /* set non-blocking and restore on close */ + +/* c->restore_block mask flags */ +#define CHANNEL_RESTORE_RFD 0x01 +#define CHANNEL_RESTORE_WFD 0x02 +#define CHANNEL_RESTORE_EFD 0x04 + +/* TCP forwarding */ +#define FORWARD_DENY 0 +#define FORWARD_REMOTE (1) +#define FORWARD_LOCAL (1<<1) +#define FORWARD_ALLOW (FORWARD_REMOTE|FORWARD_LOCAL) + +#define FORWARD_ADM 0x100 +#define FORWARD_USER 0x101 + +struct ssh; +struct Channel; +typedef struct Channel Channel; +struct fwd_perm_list; + +typedef void channel_open_fn(struct ssh *, int, int, void *); +typedef void channel_callback_fn(struct ssh *, int, int, void *); +typedef int channel_infilter_fn(struct ssh *, struct Channel *, char *, int); +typedef void channel_filter_cleanup_fn(struct ssh *, int, void *); +typedef u_char *channel_outfilter_fn(struct ssh *, struct Channel *, + u_char **, size_t *); + +/* Channel success/failure callbacks */ +typedef void channel_confirm_cb(struct ssh *, int, struct Channel *, void *); +typedef void channel_confirm_abandon_cb(struct ssh *, struct Channel *, void *); +struct channel_confirm { + TAILQ_ENTRY(channel_confirm) entry; + channel_confirm_cb *cb; + channel_confirm_abandon_cb *abandon_cb; + void *ctx; +}; +TAILQ_HEAD(channel_confirms, channel_confirm); + +/* Context for non-blocking connects */ +struct channel_connect { + char *host; + int port; + struct addrinfo *ai, *aitop; +}; + +/* Callbacks for mux channels back into client-specific code */ +typedef int mux_callback_fn(struct ssh *, struct Channel *); + +/* + * NB. channel IDs on the wire and in c->remote_id are uint32, but local + * channel IDs (e.g. c->self) only ever use the int32 subset of this range, + * because we use local channel ID -1 for housekeeping. Remote channels have + * a dedicated "have_remote_id" flag to indicate their validity. + */ + +struct Channel { + int type; /* channel type/state */ + + int self; /* my own channel identifier */ + uint32_t remote_id; /* channel identifier for remote peer */ + int have_remote_id; /* non-zero if remote_id is valid */ + + u_int istate; /* input from channel (state of receive half) */ + u_int ostate; /* output to channel (state of transmit half) */ + int flags; /* close sent/rcvd */ + int rfd; /* read fd */ + int wfd; /* write fd */ + int efd; /* extended fd */ + int sock; /* sock fd */ + u_int io_want; /* bitmask of SSH_CHAN_IO_* */ + u_int io_ready; /* bitmask of SSH_CHAN_IO_* */ + int pfds[4]; /* pollfd entries for rfd/wfd/efd/sock */ + int ctl_chan; /* control channel (multiplexed connections) */ + int isatty; /* rfd is a tty */ +#ifdef _AIX + int wfd_isatty; /* wfd is a tty */ +#endif + int client_tty; /* (client) TTY has been requested */ + int force_drain; /* force close on iEOF */ + time_t notbefore; /* Pause IO until deadline (time_t) */ + int delayed; /* post-IO handlers for newly created + * channels are delayed until the first call + * to a matching pre-IO handler. + * this way post-IO handlers are not + * accidentally called if a FD gets reused */ + int restore_block; /* fd mask to restore blocking status */ + int restore_flags[3];/* flags to restore */ + struct sshbuf *input; /* data read from socket, to be sent over + * encrypted connection */ + struct sshbuf *output; /* data received over encrypted connection for + * send on socket */ + struct sshbuf *extended; + + char *path; + /* path for unix domain sockets, or host name for forwards */ + int listening_port; /* port being listened for forwards */ + char *listening_addr; /* addr being listened for forwards */ + int host_port; /* remote port to connect for forwards */ + char *remote_name; /* remote hostname */ + + u_int remote_window; + u_int remote_maxpacket; + u_int local_window; + u_int local_window_exceeded; + u_int local_window_max; + u_int local_consumed; + u_int local_maxpacket; + int extended_usage; + int single_connection; + + char *ctype; /* const type - NB. not freed on channel_free */ + char *xctype; /* extended type */ + + /* callback */ + channel_open_fn *open_confirm; + void *open_confirm_ctx; + channel_callback_fn *detach_user; + int detach_close; + struct channel_confirms status_confirms; + + /* filter */ + channel_infilter_fn *input_filter; + channel_outfilter_fn *output_filter; + void *filter_ctx; + channel_filter_cleanup_fn *filter_cleanup; + + /* keep boundaries */ + int datagram; + + /* non-blocking connect */ + /* XXX make this a pointer so the structure can be opaque */ + struct channel_connect connect_ctx; + + /* multiplexing protocol hook, called for each packet received */ + mux_callback_fn *mux_rcb; + void *mux_ctx; + int mux_pause; + int mux_downstream_id; + + /* Inactivity timeouts */ + + /* Last traffic seen for OPEN channels */ + time_t lastused; + /* Inactivity timeout deadline in seconds (0 = no timeout) */ + int inactive_deadline; +}; + +#define CHAN_EXTENDED_IGNORE 0 +#define CHAN_EXTENDED_READ 1 +#define CHAN_EXTENDED_WRITE 2 + +/* default window/packet sizes for tcp/x11-fwd-channel */ +#define CHAN_SES_PACKET_DEFAULT (32*1024) +#define CHAN_SES_WINDOW_DEFAULT (64*CHAN_SES_PACKET_DEFAULT) +#define CHAN_TCP_PACKET_DEFAULT (32*1024) +#define CHAN_TCP_WINDOW_DEFAULT (64*CHAN_TCP_PACKET_DEFAULT) +#define CHAN_X11_PACKET_DEFAULT (16*1024) +#define CHAN_X11_WINDOW_DEFAULT (4*CHAN_X11_PACKET_DEFAULT) + +/* possible input states */ +#define CHAN_INPUT_OPEN 0 +#define CHAN_INPUT_WAIT_DRAIN 1 +#define CHAN_INPUT_WAIT_OCLOSE 2 +#define CHAN_INPUT_CLOSED 3 + +/* possible output states */ +#define CHAN_OUTPUT_OPEN 0 +#define CHAN_OUTPUT_WAIT_DRAIN 1 +#define CHAN_OUTPUT_WAIT_IEOF 2 +#define CHAN_OUTPUT_CLOSED 3 + +#define CHAN_CLOSE_SENT 0x01 +#define CHAN_CLOSE_RCVD 0x02 +#define CHAN_EOF_SENT 0x04 +#define CHAN_EOF_RCVD 0x08 +#define CHAN_LOCAL 0x10 + +/* file descriptor events */ +#define SSH_CHAN_IO_RFD 0x01 +#define SSH_CHAN_IO_WFD 0x02 +#define SSH_CHAN_IO_EFD_R 0x04 +#define SSH_CHAN_IO_EFD_W 0x08 +#define SSH_CHAN_IO_EFD (SSH_CHAN_IO_EFD_R|SSH_CHAN_IO_EFD_W) +#define SSH_CHAN_IO_SOCK_R 0x10 +#define SSH_CHAN_IO_SOCK_W 0x20 +#define SSH_CHAN_IO_SOCK (SSH_CHAN_IO_SOCK_R|SSH_CHAN_IO_SOCK_W) + +/* Read buffer size */ +#define CHAN_RBUF (16*1024) + +/* Maximum size for direct reads to buffers */ +#define CHANNEL_MAX_READ CHAN_SES_PACKET_DEFAULT + +/* Maximum channel input buffer size */ +#define CHAN_INPUT_MAX (16*1024*1024) + +/* Hard limit on number of channels */ +#define CHANNELS_MAX_CHANNELS (16*1024) + +/* check whether 'efd' is still in use */ +#define CHANNEL_EFD_INPUT_ACTIVE(c) \ + (c->extended_usage == CHAN_EXTENDED_READ && \ + (c->efd != -1 || \ + sshbuf_len(c->extended) > 0)) +#define CHANNEL_EFD_OUTPUT_ACTIVE(c) \ + (c->extended_usage == CHAN_EXTENDED_WRITE && \ + c->efd != -1 && (!(c->flags & (CHAN_EOF_RCVD|CHAN_CLOSE_RCVD)) || \ + sshbuf_len(c->extended) > 0)) + +/* Add channel management structures to SSH transport instance */ +void channel_init_channels(struct ssh *ssh); + +/* channel management */ + +Channel *channel_by_id(struct ssh *, int); +Channel *channel_by_remote_id(struct ssh *, u_int); +Channel *channel_lookup(struct ssh *, int); +Channel *channel_new(struct ssh *, char *, int, int, int, int, + u_int, u_int, int, const char *, int); +void channel_set_fds(struct ssh *, int, int, int, int, int, + int, int, u_int); +void channel_free(struct ssh *, Channel *); +void channel_free_all(struct ssh *); +void channel_stop_listening(struct ssh *); +void channel_force_close(struct ssh *, Channel *, int); +void channel_set_xtype(struct ssh *, int, const char *); + +void channel_send_open(struct ssh *, int); +void channel_request_start(struct ssh *, int, char *, int); +void channel_register_cleanup(struct ssh *, int, + channel_callback_fn *, int); +void channel_register_open_confirm(struct ssh *, int, + channel_open_fn *, void *); +void channel_register_filter(struct ssh *, int, channel_infilter_fn *, + channel_outfilter_fn *, channel_filter_cleanup_fn *, void *); +void channel_register_status_confirm(struct ssh *, int, + channel_confirm_cb *, channel_confirm_abandon_cb *, void *); +void channel_cancel_cleanup(struct ssh *, int); +int channel_close_fd(struct ssh *, Channel *, int *); +void channel_send_window_changes(struct ssh *); + +/* channel inactivity timeouts */ +void channel_add_timeout(struct ssh *, const char *, int); +void channel_clear_timeouts(struct ssh *); + +/* mux proxy support */ + +int channel_proxy_downstream(struct ssh *, Channel *mc); +int channel_proxy_upstream(Channel *, int, u_int32_t, struct ssh *); + +/* protocol handler */ + +int channel_input_data(int, u_int32_t, struct ssh *); +int channel_input_extended_data(int, u_int32_t, struct ssh *); +int channel_input_ieof(int, u_int32_t, struct ssh *); +int channel_input_oclose(int, u_int32_t, struct ssh *); +int channel_input_open_confirmation(int, u_int32_t, struct ssh *); +int channel_input_open_failure(int, u_int32_t, struct ssh *); +int channel_input_port_open(int, u_int32_t, struct ssh *); +int channel_input_window_adjust(int, u_int32_t, struct ssh *); +int channel_input_status_confirm(int, u_int32_t, struct ssh *); + +/* file descriptor handling (read/write) */ +struct pollfd; +struct timespec; + +void channel_prepare_poll(struct ssh *, struct pollfd **, + u_int *, u_int *, u_int, struct timespec *); +void channel_after_poll(struct ssh *, struct pollfd *, u_int); +int channel_output_poll(struct ssh *); + +int channel_not_very_much_buffered_data(struct ssh *); +void channel_close_all(struct ssh *); +int channel_still_open(struct ssh *); +int channel_tty_open(struct ssh *); +const char *channel_format_extended_usage(const Channel *); +char *channel_open_message(struct ssh *); +int channel_find_open(struct ssh *); + +/* tcp forwarding */ +struct Forward; +struct ForwardOptions; +void channel_set_af(struct ssh *, int af); +void channel_permit_all(struct ssh *, int); +void channel_add_permission(struct ssh *, int, int, char *, int); +void channel_clear_permission(struct ssh *, int, int); +void channel_disable_admin(struct ssh *, int); +void channel_update_permission(struct ssh *, int, int); +Channel *channel_connect_to_port(struct ssh *, const char *, u_short, + char *, char *, int *, const char **); +Channel *channel_connect_to_path(struct ssh *, const char *, char *, char *); +Channel *channel_connect_stdio_fwd(struct ssh *, const char*, + int, int, int, int); +Channel *channel_connect_by_listen_address(struct ssh *, const char *, + u_short, char *, char *); +Channel *channel_connect_by_listen_path(struct ssh *, const char *, + char *, char *); +int channel_request_remote_forwarding(struct ssh *, struct Forward *); +int channel_setup_local_fwd_listener(struct ssh *, struct Forward *, + struct ForwardOptions *); +int channel_request_rforward_cancel(struct ssh *, struct Forward *); +int channel_setup_remote_fwd_listener(struct ssh *, struct Forward *, + int *, struct ForwardOptions *); +int channel_cancel_rport_listener(struct ssh *, struct Forward *); +int channel_cancel_lport_listener(struct ssh *, struct Forward *, + int, struct ForwardOptions *); +int permitopen_port(const char *); + +/* x11 forwarding */ + +void channel_set_x11_refuse_time(struct ssh *, time_t); +int x11_connect_display(struct ssh *); +int x11_create_display_inet(struct ssh *, int, int, int, u_int *, int **); +void x11_request_forwarding_with_spoofing(struct ssh *, int, + const char *, const char *, const char *, int); + +/* channel close */ + +int chan_is_dead(struct ssh *, Channel *, int); +void chan_mark_dead(struct ssh *, Channel *); + +/* channel events */ + +void chan_rcvd_oclose(struct ssh *, Channel *); +void chan_rcvd_eow(struct ssh *, Channel *); +void chan_read_failed(struct ssh *, Channel *); +void chan_ibuf_empty(struct ssh *, Channel *); +void chan_rcvd_ieof(struct ssh *, Channel *); +void chan_write_failed(struct ssh *, Channel *); +void chan_obuf_empty(struct ssh *, Channel *); + +#endif |