ssh_session(3)

NAME

Ssh_session - functions that manage a session
Functions: int pubkey_get_hash (SSH_SESSION *session, unsigned char
hash[MD5_DIGEST_LEN]); int ssh_connect (SSH_SESSION *session)
connect to the ssh server; void ssh_disconnect (SSH_SESSION *session)
disconnect from a session (client or server); const char * ssh_get_disconnect_message (SSH_SESSION *session)
get the disconnect message from the server; int ssh_get_fd (SSH_SESSION *session)
recover the fd of connection; char * ssh_get_issue_banner (SSH_SESSION *session)
get the issue banner from the server; int ssh_get_pubkey_hash (SSH_SESSION *session, unsigned char
hash[MD5_DIGEST_LEN])
get the md5 hash of the server public key; int ssh_get_status (SSH_SESSION *session)
get session status; int ssh_get_version (SSH_SESSION *session)
get the protocol version of the session; int ssh_handle_packets (SSH_SESSION *session) int ssh_is_server_known (SSH_SESSION *session)
test if the server is known; SSH_SESSION * ssh_new ()
creates a new ssh session; int ssh_select (CHANNEL **channels, CHANNEL **outchannels, int maxfd,
fd_set *readfds, struct timeval *timeout)
wrapper for the select syscall; void ssh_set_blocking (SSH_SESSION *session, int blocking)
set the session in blocking/nonblocking mode; void ssh_set_fd_except (SSH_SESSION *session)
say the session it has an exception to catch on the file descriptor; void ssh_set_fd_toread (SSH_SESSION *session)
say to the session it has data to read on the file descriptor without blocking; void ssh_set_fd_towrite (SSH_SESSION *session)
say the session it may write to the file descriptor without blocking; void ssh_set_options (SSH_SESSION *session, SSH_OPTIONS *options)
set the options for the current session; void ssh_silent_disconnect (SSH_SESSION *session)
disconnect impolitely from remote host; int ssh_write_knownhost (SSH_SESSION *session)
write the current server as known in the known hosts file

Detailed Description

functions that manage a session

Function Documentation

int pubkey_get_hash (SSH_SESSION * session, unsigned char: hash[MD5_DIGEST_LEN])
Deprecated
same as ssh_get_pubkey_hash()
int ssh_connect (SSH_SESSION * session): connect to the ssh server; Parameters:
session ssh session; Returns:
0 on success, SSH_ERROR on error; See also:
ssh_new()

ssh_disconnect()
void ssh_disconnect (SSH_SESSION * session): disconnect from a session (client or server); Parameters:
session ssh session
const char* ssh_get_disconnect_message (SSH_SESSION * session): get the disconnect message from the server; Parameters:
session ssh session; Returns:
message sent by the server along with the disconnect, or NULL in
which case the reason of the disconnect may be found with
ssh_get_error.; See also:
ssh_get_error()
int ssh_get_fd (SSH_SESSION * session): recover the fd of connection; In case you'd need the file descriptor of the connection to the
server/client; Parameters:
session ssh session; Returns:
file descriptor of the connection, or -1 if it is not connected
char* ssh_get_issue_banner (SSH_SESSION * session): get the issue banner from the server; this is the banner showing a disclaimer to users who log in, typicaly
their right or the fact that they will be monitored; Parameters:
session ssh session; Returns:
NULL if there is no issue banner, else a string containing it.
int ssh_get_pubkey_hash (SSH_SESSION * session, unsigned char: hash[MD5_DIGEST_LEN])
get the md5 hash of the server public key; Parameters:
session ssh session
hash destination for the md5 hash; Returns:
size of the hash in bytes; Warning:
it is very important that you verify at some moment that the hash
matches a known server. If you don't do it, cryptography won't help you at making things secure; See also:
ssh_is_server_known()
int ssh_get_status (SSH_SESSION * session): get session status; Parameters:
session ssh session; Returns:
a bitmask including SSH_CLOSED, SSH_READ_PENDING or
SSH_CLOSED_ERROR which respectively means the session is closed,
has data to read on the connection socket and session was closed
due to an error
int ssh_get_version (SSH_SESSION * session): get the protocol version of the session; Parameters:
session ssh session; Returns:
1 or 2, for ssh1 or ssh2
int ssh_handle_packets (SSH_SESSION * session): Warning:
I don't remember if this should be internal or not
int ssh_is_server_known (SSH_SESSION * session): test if the server is known; checks the user's known host file for a previous connection to the
current server.; Parameters:
session ssh session; Returns:
SSH_SERVER_KNOWN_OK : the server is known and has not changed
SSH_SERVER_KNOWN_CHANGED : The server key has changed. Either you

are under attack or the administrator changed the key. you HAVE to warn the user about a possible attack

SSH_SERVER_FOUND_OTHER : the server gave use a key of a type while

we had an other type recorded. It is a possible attack

SSH_SERVER_NOT_KNOWN : the server is unknown. User should confirm

the MD5 is correct

SSH_SERVER_ERROR : Some error happened

See also:

ssh_options_set_wanted_algo()

ssh_get_pubkey_hash()

Bug

there is no current way to remove or modify an entry into the known host table
SSH_SESSION* ssh_new (): creates a new ssh session; Returns:
new ssh_session pointer
int ssh_select (CHANNEL ** channels, CHANNEL ** outchannels, int maxfd,: fd_set * readfds, struct timeval * timeout) wrapper for the select syscall; This functions acts more or less like the select(2) syscall.
There is no support for writing or exceptions.; Parameters:
channels arrays of channels pointers finished by an NULL. It is never rewritten/
outchannels arrays of same size that 'channels', it hasn't to be initialized
maxfd maximum +1 file descriptor from readfds
readfds an fd_set of file descriptors to be select'ed for reading timeout a timeout for the select; See also:
select(2); Returns:
-1 if an error occured. E_INTR if it was interrupted. In that case, just restart it.; Warning:
libssh is not threadsafe. That means that if a signal is caught
during the processing of this function, you cannot call ssh
functions on sessions that are busy with ssh_select()
void ssh_set_blocking (SSH_SESSION * session, int blocking): set the session in blocking/nonblocking mode; Parameters:
session ssh session
blocking zero for nonblocking mode; Bug
nonblocking code is in development and won't work as expected
void ssh_set_fd_except (SSH_SESSION * session): say the session it has an exception to catch on the file descriptor; Parameters:
session ssh session
void ssh_set_fd_toread (SSH_SESSION * session): say to the session it has data to read on the file descriptor without
blocking; Parameters:
session ssh session
void ssh_set_fd_towrite (SSH_SESSION * session): say the session it may write to the file descriptor without blocking; Parameters:
session ssh session
void ssh_set_options (SSH_SESSION * session, SSH_OPTIONS * options): set the options for the current session; Parameters:
session ssh session
options options structure; See also:
ssh_new()

ssh_options_new()
void ssh_silent_disconnect (SSH_SESSION * session): disconnect impolitely from remote host; Parameters:
session current ssh session
int ssh_write_knownhost (SSH_SESSION * session): write the current server as known in the known hosts file; You generaly uses it when ssh_is_server_known() answered SSH_SERVER_NOT_KNOWN; Parameters:
session ssh session; Returns:
0 on success, -1 on error

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comprehensive documentation repository

See also

ssh_session(3)

NAME

Detailed Description

Function Documentation