SSH connection layer.
This module implements the SSH connection layer.
Types:
Host = string()
Port = integer()
Options = [{Option, Value}]
Connects to an SSH server. A gen_server is started and
returned if connection is successful, but no channel is started,
that is done with session_open/2. The Host is a
string with the address of a host running an SSH server. The
Port is an integer, the port to connect to. The default
is 22, the registered port for SSH.
Options are:
-
{user_dir, String}
-
Sets the user directory, normally
~/.ssh (containing the files
known_hosts, id_rsa<c>, <c>id_dsa,
authorized_keys).
-
{silently_accept_hosts, Boolean}
-
When true, (default is false), hosts are added to the
file known_hosts without asking the user.
-
{user_interaction, Boolean}
-
If true, which is the default, password questions
and adding hosts to known_hosts will be asked
interactively to the user. (This is done during
connection to an SSH server.) If false, both these
interactions will throw and the server will not start.
-
{public_key_alg, ssh_rsa | ssh_dsa}
-
Sets the preferred public key algorithm to use for user
authentication. If the the preferred algorithm fails of
some reason, the other algorithm is tried. The default is
to try ssh_rsa first.
-
{connect_timeout, Milliseconds | infinity}
-
Sets the default timeout when trying to connect to
an SSH server. This timeout will also affect calls
later when using the SSH connection.
-
{user, String}
-
Provide a username. If this option is not given,
ssh reads from the environment (LOGNAME or
USER on unix, USERNAME on Windows).
-
{password, String}
-
Provide a password for password authentication.
If this option is not given, the user will be asked
for a password.
-
{user_auth, Fun/3}
-
Provide a fun for password authentication. The fun
will be called as fun(User, Password, Opts) and
should return true or false.
-
{key_cb, KeyCallbackModule}
-
Provide a special call-back module for key handling.
The call-back module should be modeled after the
ssh_file module. The function that must be
exported are: private_host_rsa_key/2,
private_host_dsa_key/2, lookup_host_key/3
and add_host_key/3.
-
{fd, FD}
-
Allow an existing file-descriptor to be used, given in
FD. (Simply passed on to gen_tcp:listen.)
As usual, boolean options that should be true can be
given as an atom instead of a tuple, e.g.
silently_accept_hosts instead of
{silently_accept_hosts, true}.
Types:
UserFun = fun() -> Pid
Port = integer()
Addr = string() | any
Options = [{Option, Value}]
Option = atom()
Value = term()
Starts a server listening for SSH connections on the given port.
UserFun is a function that should spawn and return a server
upon incoming connections on the given port (and address).
Port is the port that the server should listen on.
Everytime a connection is made on that port, the UserFun is
called, and the returned process is used as a user process
for the server.
Options are:
-
{system_dir, String}
-
Sets the system directory, containing the host files that
identifies the host for ssh. The default is /etc/ssh,
but note that SSH normally requires the host files there to
be readable only by root.
-
{user_passwords, [{User, Password}]}
-
Provide passwords for password authentication.They will
be used when someone tries to connect to the server and
public key user autentication fails. The option provides
a list of valid user names and the corresponding password.
User and Password are strings.
-
{password, String}
-
Provide a global password that will authenticate any
user (use with caution!).
If neither of these options is given, the server will
be unable to authenticate with password.
-
{pwdfun, fun/2}
-
Provide a function for password validation. This is called
with user and password as strings, and should return
true if the password is valid and
false otherwise.
-
{fd, FD}
-
Allow an existing file-descriptor to be used, given in
FD. (Simply passed on to gen_tcp:listen.)
Types:
Pid = pid()
Reason = atom()
Stops the listener, given by Pid, existing
connections will stay open.