The libssh callbacks

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_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.
#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.
#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

Typedefs
typedef int(*	ssh_auth_callback )(const char *prompt, char *buf, size_t len, int echo, int verify, void *userdata)
	SSH authentication callback.
typedef void(*	ssh_channel_close_callback )(ssh_session session, ssh_channel channel, void *userdata)
	SSH channel close callback.
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.
typedef void(*	ssh_channel_eof_callback )(ssh_session session, ssh_channel channel, void *userdata)
	SSH channel eof callback.
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.
typedef void(*	ssh_channel_exit_status_callback )(ssh_session session, ssh_channel channel, int exit_status, void *userdata)
	SSH channel exit status callback.
typedef void(*	ssh_channel_signal_callback )(ssh_session session, ssh_channel channel, const char *signal, void *userdata)
	SSH channel signal callback.
typedef void(*	ssh_global_request_callback )(ssh_session session, ssh_message message, void *userdata)
	SSH global request callback.
typedef void(*	ssh_log_callback )(ssh_session session, int priority, const char *message, void *userdata)
	SSH log callback.
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.
typedef void(*	ssh_status_callback )(ssh_session session, float status, void *userdata)
	SSH Connection status callback.

Functions
LIBSSH_API int	ssh_set_callbacks (ssh_session session, ssh_callbacks cb)
	Set the session callback functions.
LIBSSH_API int	ssh_set_channel_callbacks (ssh_channel channel, ssh_channel_callbacks cb)
	Set the channel callback functions.

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_callback)(const char *prompt, char *buf, size_t len, int echo, int verify, void *userdata)

SSH authentication callback.

Parameters

prompt	Prompt to be displayed.
buf	Buffer to save the password. You should null-terminate it.
len	Length of the buffer.
echo	Enable or disable the echo of what you type.
verify	Should the password be verified?
userdata	Userdata to be passed to the callback function. Useful for GUI applications.

Returns

0 on success, < 0 on error.

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.

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 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 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 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 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 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.

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.