Callback which can be replaced in libssh. More...

Data Structures
struct	ssh_callbacks
	The structure to replace libssh functions with appropriate callbacks. More...

struct	ssh_server_callbacks
	This structure can be used to implement a libssh server, with appropriate callbacks. More...

struct	ssh_socket_callbacks
	These are the callbacks exported by the socket structure They are called by the socket module when a socket event appears. More...

Macros
#define	ssh_callbacks_init(p)
	Initializes an ssh_callbacks_struct A call to this macro is mandatory when you have set a new ssh_callback_struct structure. More...

#define	SSH_PACKET_CALLBACK(name) int name (ssh_session session, uint8_t type, ssh_buffer packet, void *user)
	This macro declares a packet callback handler. More...

#define	SSH_PACKET_NOT_USED 2
	Packet was not used and should be passed to any other callback available.

#define	SSH_PACKET_USED 1
	return values for a ssh_packet_callback More...

Typedefs
typedef int(*	ssh_auth_gssapi_mic_callback) (ssh_session session, const char user, const char principal, void *userdata)
	SSH authentication callback. More...

typedef int(*	ssh_auth_none_callback) (ssh_session session, const char user, void userdata)
	SSH authentication callback. More...

typedef int(*	ssh_auth_password_callback) (ssh_session session, const char user, const char password, void *userdata)
	These are callbacks used specifically in SSH servers. More...

typedef int(*	ssh_auth_pubkey_callback) (ssh_session session, const char user, struct ssh_key_struct pubkey, char signature_state, void *userdata)
	SSH authentication callback. More...

typedef void(*	ssh_channel_auth_agent_req_callback) (ssh_session session, ssh_channel channel, void *userdata)
	SSH auth-agent-request from the client. More...

typedef void(*	ssh_channel_close_callback) (ssh_session session, ssh_channel channel, void *userdata)
	SSH channel close callback. More...

typedef int(*	ssh_channel_data_callback) (ssh_session session, ssh_channel channel, void data, uint32_t len, int is_stderr, void userdata)
	SSH channel data callback. More...

typedef int(*	ssh_channel_env_request_callback) (ssh_session session, ssh_channel channel, const char env_name, const char env_value, void *userdata)
	SSH channel environment request from a client. More...

typedef void(*	ssh_channel_eof_callback) (ssh_session session, ssh_channel channel, void *userdata)
	SSH channel eof callback. More...

typedef int(*	ssh_channel_exec_request_callback) (ssh_session session, ssh_channel channel, const char command, void userdata)
	SSH channel Exec request from a client. More...

typedef void(*	ssh_channel_exit_signal_callback) (ssh_session session, ssh_channel channel, const char signal, int core, const char errmsg, const char lang, void userdata)
	SSH channel exit signal callback. More...

typedef void(*	ssh_channel_exit_status_callback) (ssh_session session, ssh_channel channel, int exit_status, void *userdata)
	SSH channel exit status callback. More...

typedef ssh_channel(*	ssh_channel_open_request_session_callback) (ssh_session session, void *userdata)
	Handles an SSH new channel open session request. More...

typedef ssh_channel(*	ssh_channel_open_request_x11_callback) (ssh_session session, const char originator_address, int originator_port, void userdata)
	Handles an SSH new channel open X11 request. More...

typedef int(*	ssh_channel_pty_request_callback) (ssh_session session, ssh_channel channel, const char term, int width, int height, int pxwidth, int pwheight, void userdata)
	SSH channel PTY request from a client. More...

typedef int(*	ssh_channel_pty_window_change_callback) (ssh_session session, ssh_channel channel, int width, int height, int pxwidth, int pwheight, void *userdata)
	SSH channel PTY windows change (terminal size) from a client. More...

typedef int(*	ssh_channel_shell_request_callback) (ssh_session session, ssh_channel channel, void *userdata)
	SSH channel Shell request from a client. More...

typedef void(*	ssh_channel_signal_callback) (ssh_session session, ssh_channel channel, const char signal, void userdata)
	SSH channel signal callback. More...

typedef int(*	ssh_channel_subsystem_request_callback) (ssh_session session, ssh_channel channel, const char subsystem, void userdata)
	SSH channel subsystem request from a client. More...

typedef void(*	ssh_channel_x11_req_callback) (ssh_session session, ssh_channel channel, int single_connection, const char auth_protocol, const char auth_cookie, uint32_t screen_number, void *userdata)
	SSH X11 request from the client. More...

typedef void(*	ssh_global_request_callback) (ssh_session session, ssh_message message, void *userdata)
	SSH global request callback. More...

typedef void(*	ssh_log_callback) (ssh_session session, int priority, const char message, void userdata)
	SSH log callback. More...

typedef void(*	ssh_logging_callback) (int priority, const char function, const char buffer, void *userdata)
	SSH log callback. More...

typedef int(*	ssh_packet_callback) (ssh_session session, uint8_t type, ssh_buffer packet, void *user)
	Prototype for a packet callback, to be called when a new packet arrives. More...

typedef int(*	ssh_service_request_callback) (ssh_session session, const char service, void userdata)
	Handles an SSH service request. More...

typedef void(*	ssh_status_callback) (ssh_session session, float status, void *userdata)
	SSH Connection status callback. More...

Functions
LIBSSH_API int	ssh_set_callbacks (ssh_session session, ssh_callbacks cb)
	Set the session callback functions. More...

LIBSSH_API int	ssh_set_channel_callbacks (ssh_channel channel, ssh_channel_callbacks cb)
	Set the channel callback functions. More...

LIBSSH_API int	ssh_set_server_callbacks (ssh_session session, ssh_server_callbacks cb)
	Set the session server callback functions. More...

Detailed Description

Callback which can be replaced in libssh.

Macro Definition Documentation

#define ssh_callbacks_init ( p )

Value:

do {\
  (p)->size=sizeof(*(p)); \
} while(0);

Initializes an ssh_callbacks_struct A call to this macro is mandatory when you have set a new ssh_callback_struct structure.

Its goal is to maintain the binary compatibility with future versions of libssh as the structure evolves with time.

#define SSH_PACKET_CALLBACK ( name ) int name (ssh_session session, uint8_t type, ssh_buffer packet, void *user)

This macro declares a packet callback handler.

 SSH_PACKET_CALLBACK(mycallback){
 ...
 }

#define SSH_PACKET_USED 1

return values for a ssh_packet_callback

Packet was used and should not be parsed by another callback

Typedef Documentation

typedef int(* ssh_auth_gssapi_mic_callback) (ssh_session session, const char *user, const char *principal, void *userdata)

SSH authentication callback.

Tries to authenticates user with the "gssapi-with-mic" method

Parameters

session	Current session handler
user	Username of the user (can be spoofed)
principal	Authenticated principal of the user, including realm.
userdata	Userdata to be passed to the callback function.

Returns: SSH_AUTH_SUCCESS Authentication is accepted.; SSH_AUTH_PARTIAL Partial authentication, more authentication means are needed.; SSH_AUTH_DENIED Authentication failed.

Warning: Implementations should verify that parameter user matches in some way the principal. user and principal can be different. Only the latter is guaranteed to be safe.

typedef int(* ssh_auth_none_callback) (ssh_session session, const char *user, void *userdata)

SSH authentication callback.

Tries to authenticates user with the "none" method which is anonymous or passwordless.

Parameters

session	Current session handler
user	User that wants to authenticate
userdata	Userdata to be passed to the callback function.

Returns: SSH_AUTH_SUCCESS Authentication is accepted.; SSH_AUTH_PARTIAL Partial authentication, more authentication means are needed.; SSH_AUTH_DENIED Authentication failed.

typedef int(* ssh_auth_password_callback) (ssh_session session, const char *user, const char *password, void *userdata)

These are callbacks used specifically in SSH servers.

SSH authentication callback.

Parameters

session	Current session handler
user	User that wants to authenticate
password	Password used for authentication
userdata	Userdata to be passed to the callback function.

Returns: SSH_AUTH_SUCCESS Authentication is accepted.; SSH_AUTH_PARTIAL Partial authentication, more authentication means are needed.; SSH_AUTH_DENIED Authentication failed.

typedef int(* ssh_auth_pubkey_callback) (ssh_session session, const char *user, struct ssh_key_struct *pubkey, char signature_state, void *userdata)

SSH authentication callback.

Parameters

session	Current session handler
user	User that wants to authenticate
pubkey	public key used for authentication
signature_state	SSH_PUBLICKEY_STATE_NONE if the key is not signed (simple public key probe), SSH_PUBLICKEY_STATE_VALID if the signature is valid. Others values should be replied with a SSH_AUTH_DENIED.
userdata	Userdata to be passed to the callback function.

Returns: SSH_AUTH_SUCCESS Authentication is accepted.; SSH_AUTH_PARTIAL Partial authentication, more authentication means are needed.; SSH_AUTH_DENIED Authentication failed.

typedef void(* ssh_channel_auth_agent_req_callback) (ssh_session session, ssh_channel channel, void *userdata)

SSH auth-agent-request from the client.

This request is sent by a client when agent forwarding is available. Server is free to ignore this callback, no answer is expected.

Parameters

channel	the channel
userdata	Userdata to be passed to the callback function.

typedef void(* ssh_channel_close_callback) (ssh_session session, ssh_channel channel, void *userdata)

SSH channel close callback.

Called when a channel is closed by remote peer

Parameters

session	Current session handler
channel	the actual channel
userdata	Userdata to be passed to the callback function.

typedef int(* ssh_channel_data_callback) (ssh_session session, ssh_channel channel, void *data, uint32_t len, int is_stderr, void *userdata)

SSH channel data callback.

Called when data is available on a channel

Parameters

session	Current session handler
channel	the actual channel
data	the data that has been read on the channel
len	the length of the data
is_stderr	is 0 for stdout or 1 for stderr
userdata	Userdata to be passed to the callback function.

Returns: number of bytes processed by the callee. The remaining bytes will be sent in the next callback message, when more data is available.

typedef int(* ssh_channel_env_request_callback) (ssh_session session, ssh_channel channel, const char *env_name, const char *env_value, void *userdata)

SSH channel environment request from a client.

Parameters

channel	the channel
env_name	name of the environment value to be set
env_value	value of the environment value to be set
userdata	Userdata to be passed to the callback function.

Returns: 0 if the env request is accepted; 1 if the request is denied

Warning: some environment variables can be dangerous if changed (e.g. LD_PRELOAD) and should not be fulfilled.

typedef void(* ssh_channel_eof_callback) (ssh_session session, ssh_channel channel, void *userdata)

SSH channel eof callback.

Called when a channel receives EOF

Parameters

session	Current session handler
channel	the actual channel
userdata	Userdata to be passed to the callback function.

typedef int(* ssh_channel_exec_request_callback) (ssh_session session, ssh_channel channel, const char *command, void *userdata)

SSH channel Exec request from a client.

Parameters

channel	the channel
command	the shell command to be executed
userdata	Userdata to be passed to the callback function.

Returns: 0 if the exec request is accepted; 1 if the request is denied

typedef void(* ssh_channel_exit_signal_callback) (ssh_session session, ssh_channel channel, const char *signal, int core, const char *errmsg, const char *lang, void *userdata)

SSH channel exit signal callback.

Called when a channel has received an exit signal

Parameters

session	Current session handler
channel	the actual channel
signal	the signal name (without the SIG prefix)
core	a boolean telling wether a core has been dumped or not
errmsg	the description of the exception
lang	the language of the description (format: RFC 3066)
userdata	Userdata to be passed to the callback function.

typedef void(* ssh_channel_exit_status_callback) (ssh_session session, ssh_channel channel, int exit_status, void *userdata)

SSH channel exit status callback.

Called when a channel has received an exit status

Parameters

session	Current session handler
channel	the actual channel
userdata	Userdata to be passed to the callback function.

typedef ssh_channel(* ssh_channel_open_request_session_callback) (ssh_session session, void *userdata)

Handles an SSH new channel open session request.

Parameters

session	current session handler
userdata	Userdata to be passed to the callback function.

Returns: a valid ssh_channel handle if the request is to be allowed; NULL if the request should not be allowed

Warning: The channel pointer returned by this callback must be closed by the application.

typedef ssh_channel(* ssh_channel_open_request_x11_callback) (ssh_session session, const char *originator_address, int originator_port, void *userdata)

Handles an SSH new channel open X11 request.

This happens when the server sends back an X11 connection attempt. This is a client-side API

Parameters

session	current session handler
userdata	Userdata to be passed to the callback function.

Returns: a valid ssh_channel handle if the request is to be allowed; NULL if the request should not be allowed

Warning: The channel pointer returned by this callback must be closed by the application.

typedef int(* ssh_channel_pty_request_callback) (ssh_session session, ssh_channel channel, const char *term, int width, int height, int pxwidth, int pwheight, void *userdata)

SSH channel PTY request from a client.

Parameters

channel	the channel
term	The type of terminal emulation
width	width of the terminal, in characters
height	height of the terminal, in characters
pxwidth	width of the terminal, in pixels
pxheight	height of the terminal, in pixels
userdata	Userdata to be passed to the callback function.

Returns: 0 if the pty request is accepted; -1 if the request is denied

typedef int(* ssh_channel_pty_window_change_callback) (ssh_session session, ssh_channel channel, int width, int height, int pxwidth, int pwheight, void *userdata)

SSH channel PTY windows change (terminal size) from a client.

Parameters

channel	the channel
width	width of the terminal, in characters
height	height of the terminal, in characters
pxwidth	width of the terminal, in pixels
pxheight	height of the terminal, in pixels
userdata	Userdata to be passed to the callback function.

Returns: 0 if the pty request is accepted; -1 if the request is denied

typedef int(* ssh_channel_shell_request_callback) (ssh_session session, ssh_channel channel, void *userdata)

SSH channel Shell request from a client.

Parameters

channel	the channel
userdata	Userdata to be passed to the callback function.

Returns: 0 if the shell request is accepted; 1 if the request is denied

typedef void(* ssh_channel_signal_callback) (ssh_session session, ssh_channel channel, const char *signal, void *userdata)

SSH channel signal callback.

Called when a channel has received a signal

Parameters

session	Current session handler
channel	the actual channel
signal	the signal name (without the SIG prefix)
userdata	Userdata to be passed to the callback function.

typedef int(* ssh_channel_subsystem_request_callback) (ssh_session session, ssh_channel channel, const char *subsystem, void *userdata)

SSH channel subsystem request from a client.

Parameters

channel	the channel
subsystem	the subsystem required
userdata	Userdata to be passed to the callback function.

Returns: 0 if the subsystem request is accepted; 1 if the request is denied

typedef void(* ssh_channel_x11_req_callback) (ssh_session session, ssh_channel channel, int single_connection, const char *auth_protocol, const char *auth_cookie, uint32_t screen_number, void *userdata)

SSH X11 request from the client.

This request is sent by a client when X11 forwarding is requested(and available). Server is free to ignore this callback, no answer is expected.

Parameters

channel	the channel
userdata	Userdata to be passed to the callback function.

typedef void(* ssh_global_request_callback) (ssh_session session, ssh_message message, void *userdata)

SSH global request callback.

All global request will go through this callback.

Parameters

session	Current session handler
message	the actual message
userdata	Userdata to be passed to the callback function.

typedef void(* ssh_log_callback) (ssh_session session, int priority, const char *message, void *userdata)

SSH log callback.

All logging messages will go through this callback

Parameters

session	Current session handler
priority	Priority of the log, the smaller being the more important
message	the actual message
userdata	Userdata to be passed to the callback function.

typedef void(* ssh_logging_callback) (int priority, const char *function, const char *buffer, void *userdata)

SSH log callback.

All logging messages will go through this callback.

Parameters

priority	Priority of the log, the smaller being the more important.
function	The function name calling the the logging fucntions.
message	The actual message
userdata	Userdata to be passed to the callback function.

typedef int(* ssh_packet_callback) (ssh_session session, uint8_t type, ssh_buffer packet, void *user)

Prototype for a packet callback, to be called when a new packet arrives.

Parameters

session	The current session of the packet
type	packet type (see ssh2.h)
packet	buffer containing the packet, excluding size, type and padding fields
user	user argument to the callback and are called each time a packet shows up

Returns: SSH_PACKET_USED Packet was parsed and used; SSH_PACKET_NOT_USED Packet was not used or understood, processing must continue

typedef int(* ssh_service_request_callback) (ssh_session session, const char *service, void *userdata)

Handles an SSH service request.

Parameters

session	current session handler
service	name of the service (e.g. "ssh-userauth") requested
userdata	Userdata to be passed to the callback function.

Returns: 0 if the request is to be allowed; -1 if the request should not be allowed

typedef void(* ssh_status_callback) (ssh_session session, float status, void *userdata)

SSH Connection status callback.

Parameters

session	Current session handler
status	Percentage of connection status, going from 0.0 to 1.0 once connection is done.
userdata	Userdata to be passed to the callback function.

Function Documentation

LIBSSH_API int ssh_set_callbacks	(	ssh_session	session,
		ssh_callbacks	cb
	)

Set the session callback functions.

This functions sets the callback structure to use your own callback functions for auth, logging and status.

 struct ssh_callbacks_struct cb = {
   .userdata = data,
   .auth_function = my_auth_function
 };
 ssh_callbacks_init(&cb);
 ssh_set_callbacks(session, &cb);

Parameters

session	The session to set the callback structure.
cb	The callback structure itself.

Returns: SSH_OK on success, SSH_ERROR on error.

References ssh_get_log_callback(), ssh_set_log_callback(), and ssh_set_log_userdata().

LIBSSH_API int ssh_set_channel_callbacks	(	ssh_channel	channel,
		ssh_channel_callbacks	cb
	)

Set the channel callback functions.

This functions sets the callback structure to use your own callback functions for channel data and exceptions

 struct ssh_channel_callbacks_struct cb = {
   .userdata = data,
   .channel_data = my_channel_data_function
 };
 ssh_callbacks_init(&cb);
 ssh_set_channel_callbacks(channel, &cb);

Parameters

channel	The channel to set the callback structure.
cb	The callback structure itself.

Returns: SSH_OK on success, SSH_ERROR on error.

LIBSSH_API int ssh_set_server_callbacks	(	ssh_session	session,
		ssh_server_callbacks	cb
	)

Set the session server callback functions.

This functions sets the callback structure to use your own callback functions for user authentication, new channels and requests.

 struct ssh_server_callbacks_struct cb = {
   .userdata = data,
   .auth_password_function = my_auth_function
 };
 ssh_callbacks_init(&cb);
 ssh_set_server_callbacks(session, &cb);

Parameters

session	The session to set the callback structure.
cb	The callback structure itself.

Returns: SSH_OK on success, SSH_ERROR on error.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

Typedef Documentation

Function Documentation