6 /* Definitions for channel types. */
7 #define SSH_CHANNEL_FREE 0 /* This channel is free (unused). */
8 #define SSH_CHANNEL_X11_LISTENER 1 /* Listening for inet X11 conn. */
9 #define SSH_CHANNEL_PORT_LISTENER 2 /* Listening on a port. */
10 #define SSH_CHANNEL_OPENING 3 /* waiting for confirmation */
11 #define SSH_CHANNEL_OPEN 4 /* normal open two-way channel */
12 #define SSH_CHANNEL_CLOSED 5 /* waiting for close confirmation */
13 #define SSH_CHANNEL_AUTH_SOCKET 6 /* authentication socket */
14 #define SSH_CHANNEL_X11_OPEN 7 /* reading first X11 packet */
15 #define SSH_CHANNEL_INPUT_DRAINING 8 /* sending remaining data to conn */
16 #define SSH_CHANNEL_OUTPUT_DRAINING 9 /* sending remaining data to app */
17 #define SSH_CHANNEL_LARVAL 10 /* larval session */
18 #define SSH_CHANNEL_MAX_TYPE 11
21 * Data structure for channel data. This is iniailized in channel_allocate
22 * and cleared in channel_free.
24 typedef void channel_callback_fn(int id, void *arg);
26 typedef struct Channel {
27 int type; /* channel type/state */
28 int self; /* my own channel identifier */
29 int remote_id; /* channel identifier for remote peer */
30 /* peer can be reached over encrypted connection, via packet-sent */
31 int istate; /* input from channel (state of receive half) */
32 int ostate; /* output to channel (state of transmit half) */
33 int flags; /* close sent/rcvd */
34 int rfd; /* read fd */
35 int wfd; /* write fd */
36 int efd; /* extended fd */
37 int sock; /* sock fd */
38 Buffer input; /* data read from socket, to be sent over
39 * encrypted connection */
40 Buffer output; /* data received over encrypted connection for
43 char path[200]; /* path for unix domain sockets, or host name
45 int listening_port; /* port being listened for forwards */
46 int host_port; /* remote port to connect for forwards */
47 char *remote_name; /* remote hostname */
57 char *ctype; /* type */
60 channel_callback_fn *cb_fn;
63 channel_callback_fn *dettach_user;
66 #define CHAN_EXTENDED_IGNORE 0
67 #define CHAN_EXTENDED_READ 1
68 #define CHAN_EXTENDED_WRITE 2
70 void channel_set_fds(int id, int rfd, int wfd, int efd, int extusage);
71 void channel_open(int id);
72 void channel_request(int id, char *service, int wantconfirm);
73 void channel_request_start(int id, char *service, int wantconfirm);
74 void channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg);
75 void channel_register_cleanup(int id, channel_callback_fn *fn);
76 void channel_cancel_cleanup(int id);
77 Channel *channel_lookup(int id);
80 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
81 int window, int maxpack, int extended_usage, char *remote_name);
83 void channel_input_channel_request(int type, int plen);
84 void channel_input_close(int type, int plen);
85 void channel_input_close_confirmation(int type, int plen);
86 void channel_input_data(int type, int plen);
87 void channel_input_extended_data(int type, int plen);
88 void channel_input_ieof(int type, int plen);
89 void channel_input_oclose(int type, int plen);
90 void channel_input_open_confirmation(int type, int plen);
91 void channel_input_open_failure(int type, int plen);
92 void channel_input_port_open(int type, int plen);
93 void channel_input_window_adjust(int type, int plen);
94 void channel_input_open(int type, int plen);
96 /* Sets specific protocol options. */
97 void channel_set_options(int hostname_in_open);
100 * Allocate a new channel object and set its type and socket. Remote_name
101 * must have been allocated with xmalloc; this will free it when the channel
104 int channel_allocate(int type, int sock, char *remote_name);
106 /* Free the channel and close its socket. */
107 void channel_free(int channel);
109 /* Add any bits relevant to channels in select bitmasks. */
110 void channel_prepare_select(fd_set * readset, fd_set * writeset);
113 * After select, perform any appropriate operations for channels which have
116 void channel_after_select(fd_set * readset, fd_set * writeset);
118 /* If there is data to send to the connection, send some of it now. */
119 void channel_output_poll(void);
121 /* Returns true if no channel has too much buffered data. */
122 int channel_not_very_much_buffered_data(void);
124 /* This closes any sockets that are listening for connections; this removes
125 any unix domain sockets. */
126 void channel_stop_listening(void);
129 * Closes the sockets of all channels. This is used to close extra file
130 * descriptors after a fork.
132 void channel_close_all(void);
134 /* Returns the maximum file descriptor number used by the channels. */
135 int channel_max_fd(void);
137 /* Returns true if there is still an open channel over the connection. */
138 int channel_still_open(void);
141 * Returns a string containing a list of all open channels. The list is
142 * suitable for displaying to the user. It uses crlf instead of newlines.
143 * The caller should free the string with xfree.
145 char *channel_open_message(void);
148 * Initiate forwarding of connections to local port "port" through the secure
149 * channel to host:port from remote side. This never returns if there was an
153 channel_request_local_forwarding(u_short port, const char *host,
154 u_short remote_port, int gateway_ports);
157 * Initiate forwarding of connections to port "port" on remote host through
158 * the secure channel to host:port from local side. This never returns if
159 * there was an error. This registers that open requests for that port are
163 channel_request_remote_forwarding(u_short port, const char *host,
164 u_short remote_port);
167 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
168 * called by the server, because the user could connect to any port anyway,
169 * and the server has no way to know but to trust the client anyway.
171 void channel_permit_all_opens(void);
174 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
175 * listening for the port, and sends back a success reply (or disconnect
176 * message if there was an error). This never returns if there was an error.
178 void channel_input_port_forward_request(int is_root);
181 * Creates a port for X11 connections, and starts listening for it. Returns
182 * the display name, or NULL if an error was encountered.
184 char *x11_create_display(int screen);
187 * Creates an internet domain socket for listening for X11 connections.
188 * Returns a suitable value for the DISPLAY variable, or NULL if an error
191 char *x11_create_display_inet(int screen, int x11_display_offset);
194 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
195 * the remote channel number. We should do whatever we want, and respond
196 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
198 void x11_input_open(int type, int plen);
201 * Requests forwarding of X11 connections. This should be called on the
204 void x11_request_forwarding(void);
207 * Requests forwarding for X11 connections, with authentication spoofing.
208 * This should be called in the client only.
210 void x11_request_forwarding_with_spoofing(const char *proto, const char *data);
212 /* Sends a message to the server to request authentication fd forwarding. */
213 void auth_request_forwarding(void);
216 * Returns the name of the forwarded authentication socket. Returns NULL if
217 * there is no forwarded authentication socket. The returned value points to
220 char *auth_get_socket_name(void);
223 * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
224 * This starts forwarding authentication requests.
226 void auth_input_request_forwarding(struct passwd * pw);
228 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
229 void auth_input_open_request(int type, int plen);
232 int channel_connect_to(const char *host, u_short host_port);