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 rfd; /* read fd */
34 int wfd; /* write fd */
35 int efd; /* extended fd */
36 int sock; /* sock fd */
37 Buffer input; /* data read from socket, to be sent over
38 * encrypted connection */
39 Buffer output; /* data received over encrypted connection for
42 char path[200]; /* path for unix domain sockets, or host name
44 int listening_port; /* port being listened for forwards */
45 int host_port; /* remote port to connect for forwards */
46 char *remote_name; /* remote hostname */
56 char *ctype; /* type */
59 channel_callback_fn *cb_fn;
62 channel_callback_fn *dettach_user;
65 #define CHAN_EXTENDED_IGNORE 0
66 #define CHAN_EXTENDED_READ 1
67 #define CHAN_EXTENDED_WRITE 2
69 void channel_open(int id);
70 Channel *channel_lookup(int id);
73 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
74 int window, int maxpack, int extended_usage, char *remote_name);
76 void channel_input_close(int type, int plen);
77 void channel_input_close_confirmation(int type, int plen);
78 void channel_input_data(int type, int plen);
79 void channel_input_ieof(int type, int plen);
80 void channel_input_oclose(int type, int plen);
81 void channel_input_open_confirmation(int type, int plen);
82 void channel_input_open_failure(int type, int plen);
83 void channel_input_port_open(int type, int plen);
84 void channel_input_open(int type, int plen);
86 /* Sets specific protocol options. */
87 void channel_set_options(int hostname_in_open);
90 * Allocate a new channel object and set its type and socket. Remote_name
91 * must have been allocated with xmalloc; this will free it when the channel
94 int channel_allocate(int type, int sock, char *remote_name);
96 /* Free the channel and close its socket. */
97 void channel_free(int channel);
99 /* Add any bits relevant to channels in select bitmasks. */
100 void channel_prepare_select(fd_set * readset, fd_set * writeset);
103 * After select, perform any appropriate operations for channels which have
106 void channel_after_select(fd_set * readset, fd_set * writeset);
108 /* If there is data to send to the connection, send some of it now. */
109 void channel_output_poll(void);
111 /* Returns true if no channel has too much buffered data. */
112 int channel_not_very_much_buffered_data(void);
114 /* This closes any sockets that are listening for connections; this removes
115 any unix domain sockets. */
116 void channel_stop_listening(void);
119 * Closes the sockets of all channels. This is used to close extra file
120 * descriptors after a fork.
122 void channel_close_all(void);
124 /* Returns the maximum file descriptor number used by the channels. */
125 int channel_max_fd(void);
127 /* Returns true if there is still an open channel over the connection. */
128 int channel_still_open(void);
131 * Returns a string containing a list of all open channels. The list is
132 * suitable for displaying to the user. It uses crlf instead of newlines.
133 * The caller should free the string with xfree.
135 char *channel_open_message(void);
138 * Initiate forwarding of connections to local port "port" through the secure
139 * channel to host:port from remote side. This never returns if there was an
143 channel_request_local_forwarding(u_short port, const char *host,
144 u_short remote_port, int gateway_ports);
147 * Initiate forwarding of connections to port "port" on remote host through
148 * the secure channel to host:port from local side. This never returns if
149 * there was an error. This registers that open requests for that port are
153 channel_request_remote_forwarding(u_short port, const char *host,
154 u_short remote_port);
157 * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
158 * called by the server, because the user could connect to any port anyway,
159 * and the server has no way to know but to trust the client anyway.
161 void channel_permit_all_opens(void);
164 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
165 * listening for the port, and sends back a success reply (or disconnect
166 * message if there was an error). This never returns if there was an error.
168 void channel_input_port_forward_request(int is_root);
171 * Creates a port for X11 connections, and starts listening for it. Returns
172 * the display name, or NULL if an error was encountered.
174 char *x11_create_display(int screen);
177 * Creates an internet domain socket for listening for X11 connections.
178 * Returns a suitable value for the DISPLAY variable, or NULL if an error
181 char *x11_create_display_inet(int screen, int x11_display_offset);
184 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains
185 * the remote channel number. We should do whatever we want, and respond
186 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
188 void x11_input_open(int type, int plen);
191 * Requests forwarding of X11 connections. This should be called on the
194 void x11_request_forwarding(void);
197 * Requests forwarding for X11 connections, with authentication spoofing.
198 * This should be called in the client only.
200 void x11_request_forwarding_with_spoofing(const char *proto, const char *data);
202 /* Sends a message to the server to request authentication fd forwarding. */
203 void auth_request_forwarding(void);
206 * Returns the name of the forwarded authentication socket. Returns NULL if
207 * there is no forwarded authentication socket. The returned value points to
210 char *auth_get_socket_name(void);
213 * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
214 * This starts forwarding authentication requests.
216 void auth_input_request_forwarding(struct passwd * pw);
218 /* This is called to process an SSH_SMSG_AGENT_OPEN message. */
219 void auth_input_open_request(int type, int plen);