prelude-client

prelude-client — Creating a Prelude Client

Functions

Types and Values

Description

In order to send or to read data from a Prelude collector (prelude-manager), you will need to create a prelude_client_t object. This object will be necessary for most of the work you are going to do with prelude.

<title>Creating the client</title>

int ret;
prelude_client_t *client;
ret = prelude_client_new(&client, "my-analyzer");
if ( ! client ) {
        prelude_perror(ret, "Unable to create a prelude client object");
        return -1;
}

This will create a new client object, whose default profile is my-analyzer. This default profile might be overriden using the --prelude --profile profile_name option on your command line as parsed by prelude_init().

Additionally, prelude specific option might be overriden using a Prelude specific configuration file, like the template file created within each profile, or a configuration file specified using prelude_client_set_config_filename() before prelude_client_start() is called.

The default required permission for the created client are set to PRELUDE_CONNECTION_PERMISSION_IDMEF_WRITE and PRELUDE_CONNECTION_PERMISSION_ADMIN_READ, which mean the client will reject any certificate where permission are set to anything less than this. You can change the default required permission using the prelude_client_set_required_permission() function.

As an example, if you want to create a client that will read alert from a Manager, and accept administrative option request you should use:

prelude_client_set_required_permission(client, PRELUDE_CONNECTION_PERMISSION_IDMEF_READ|PRELUDE_CONNECTION_PERMISSION_ADMIN_WRITE);

Once the client is created and you have everything setup, you will need to start your client. The prelude_client_start() function is responsible for this, and will trigger the connection to the configured manager, and send the initial client heartbeat.

ret = prelude_client_start(client);
if ( ret < 0 ) {
       prelude_log(ret, "Unable to start prelude client");
       return -1;
}

Additionally, it is possible to set additional client flags, however, you should be careful since some of theses flags (marked asynchronous) will result in creating an internal thread, which should only be done after an eventual fork of the program since threads are not copied accross a fork call.

The prelude library will also register an internal timer in order to send heartbeat message at the defined interval. Timer registered by the library itself or by the program will either be called automatically if the PRELUDE_CLIENT_FLAGS_ASYNC_TIMER flags is set, otherwise, the program is responsible for calling the prelude_timer_wake_up() function every second from it's main loop, in order to check the registered timer.

ret = prelude_client_set_flags(client, PRELUDE_CLIENT_FLAGS_ASYNC_SEND|PRELUDE_CLIENT_FLAGS_ASYNC_TIMER);
if ( ret < 0 ) {
       fprintf(stderr, "Unable to set asynchronous send and timer.\n");
       return -1;
}

<title>Sending IDMEF message</title>

For documentation on how to create IDMEF message, please see idmef_message_t or idmef_path_t.

Once you created and IDMEF message, you should use the prelude_client_send_idmef() function in order to send it to the collector you are connected to.

1
prelude_client_send_idmef(client, idmef);

<title>Destroying the client</title>

In case the analyzer you are developing is not a persistant analyzer (meaning an analyzer that is not supposed to exit), it is important that you call the prelude_client_destroy() function prior to exiting. This function have the side effect of sending an heartbeat to the remote manager, as well as an information regarding the analyzer state.

This state information is important since an analyzer not reporting a successful exit status, or an analyzer which stop sending heartbeat at all will be reported as having a problem.

  • PRELUDE_CLIENT_STATUS_EXIT_SUCCESS - Exiting the sensor is the expected behavior.
  • PRELUDE_CLIENT_STATUS_EXIT_FAILED - There is something wrong going on, notice the security analyst.

1
prelude_client_destroy(client, PRELUDE_CLIENT_STATUS_EXIT_SUCCESS);

As a side note, please remember that a persistant sensor should never use this function (except maybe if it is working in batch mode), unless it want to report the PRELUDE_CLIENT_STATUS_EXIT_FAILED exit status. This is also the case if your persistant sensor is interrupted by a signal.

Functions

prelude_client_get_unique_ident ()

prelude_ident_t *
prelude_client_get_unique_ident (prelude_client_t *client);


prelude_client_set_connection_pool ()

void
prelude_client_set_connection_pool (prelude_client_t *client,
                                    prelude_connection_pool_t *pool);

Use this function in order to set your own list of peer that client should send message too. This might be usefull in case you don't want this to be automated by prelude_client_init().

Parameters

client

pointer to a prelude_client_t object.

 

pool

pointer to a prelude_client_pool_t object.

 

prelude_client_get_connection_pool ()

prelude_connection_pool_t *
prelude_client_get_connection_pool (prelude_client_t *client);

Return a pointer to the prelude_connection_pool_t object used by client to send messages.

Parameters

client

pointer to a prelude_client_t object.

 

Returns

a pointer to a prelude_connection_pool_t object.


prelude_client_start ()

int
prelude_client_start (prelude_client_t *client);

This function start the client object, triggering a connection from the client to it's server if any were specified, and sending the initial client heartbeat.

If client was not initialized, then prelude_client_init() will be called and thus this function might fail if the client was not registered.

Parameters

client

Pointer to a client object to initialize.

 

Returns

0 on success, -1 if an error occured.


prelude_client_init ()

int
prelude_client_init (prelude_client_t *client);

This function initialize the client object, meaning reading generic options from the prelude_client_new() provided configuration file and the array of arguments specified through prelude_init().

Calling this function is optional and should be done only if you need more granularity between prelude_client_new() and prelude_client_start():

prelude_client_start() will call prelude_client_init() for you if needed.

Parameters

client

Pointer to a prelude_client_t object to initialize.

 

Returns

0 on success, -1 if an error occured.


prelude_client_new ()

int
prelude_client_new (prelude_client_t **client,
                    const char *profile);

This function initialize the client object.

Parameters

client

Pointer to a client object to initialize.

 

profile

Default profile name for this analyzer.

 

Returns

0 on success or a negative value if an error occur.


prelude_client_ref ()

prelude_client_t *
prelude_client_ref (prelude_client_t *client);


prelude_client_get_analyzer ()

idmef_analyzer_t *
prelude_client_get_analyzer (prelude_client_t *client);

Provide access to the idmef_analyzer_t object associated to client . This analyzer object is sent along with every alerts and heartbeats emited by this client. The analyzer object is created by prelude_client_init().

Parameters

client

Pointer to a prelude_client_t object.

 

Returns

the idmef_analyzer_t object associated with client .


prelude_client_get_flags ()

prelude_client_flags_t
prelude_client_get_flags (prelude_client_t *client);

Get flags set through prelude_client_set_flags().

Parameters

client

Pointer on a prelude_client_t object.

 

Returns

an or'ed list of prelude_client_flags_t.


prelude_client_set_required_permission ()

void
prelude_client_set_required_permission
                               (prelude_client_t *client,
                                prelude_connection_permission_t permission);

Set the required permission for client . The default is PRELUDE_CONNECTION_PERMISSION_IDMEF_WRITE | PRELUDE_CONNECTION_PERMISSION_ADMIN_READ. Value set through this function should be set before prelude_client_start().

If the client certificate for connecting to one of the specified manager doesn't have theses permission the client will reject the certificate and ask for registration.

Parameters

client

Pointer on a prelude_client_t object.

 

permission

Required permission for client .

 

prelude_client_get_required_permission ()

prelude_connection_permission_t
prelude_client_get_required_permission
                               (prelude_client_t *client);

Parameters

client

Pointer on a prelude_client_t object.

 

Returns

client permission as set with prelude_client_set_required_permission()


prelude_client_send_msg ()

void
prelude_client_send_msg (prelude_client_t *client,
                         prelude_msg_t *msg);

Send msg to the peers client is communicating with.

The message will be sent asynchronously if PRELUDE_CLIENT_FLAGS_ASYNC_SEND was set using prelude_client_set_flags() in which case the caller should not call prelude_msg_destroy() on msg .

Parameters

client

Pointer to a prelude_client_t object.

 

msg

pointer to a message that client should send.

 

prelude_client_recv_msg ()

int
prelude_client_recv_msg (prelude_client_t *client,
                         int timeout,
                         prelude_msg_t **msg);

Wait timeout second for a message on client connection pool.

A timeout of -1, mean prelude_client_recv_msg() will block until a message is received. A timeout of 0 mean that it will return immediatly.

Parameters

client

Pointer to a prelude_client_t object.

 

timeout

Number of millisecond to wait for a message.

 

msg

Pointer where the received prelude_msg_t should be stored.

 

Returns

0 on timeout, a negative value on error, 1 on success.


prelude_client_set_heartbeat_cb ()

void
prelude_client_set_heartbeat_cb (prelude_client_t *client,
                                 void (*cb) (prelude_client_t *client, idmef_message_t *hb));

Use if you want to override the default function used to automatically send heartbeat to client peers.

Parameters

client

pointer to a prelude_client_t object.

 

cb

pointer to a function handling heartbeat sending.

 

prelude_client_send_idmef ()

void
prelude_client_send_idmef (prelude_client_t *client,
                           idmef_message_t *msg);

Send msg to the peers client is communicating with.

The message will be sent asynchronously if PRELUDE_CLIENT_FLAGS_ASYNC_SEND was set using prelude_client_set_flags().

Parameters

client

Pointer to a prelude_client_t object.

 

msg

pointer to an IDMEF message to be sent to client peers.

 

prelude_client_recv_idmef ()

int
prelude_client_recv_idmef (prelude_client_t *client,
                           int timeout,
                           idmef_message_t **idmef);

Wait timeout second for a message on client connection pool.

A timeout of -1, mean prelude_client_recv_idmef() will block until a message is received. A timeout of 0 mean that it will return immediatly.

Parameters

client

Pointer to a prelude_client_t object.

 

timeout

Number of second to wait for a message.

 

idmef

Pointer where the received idmef_message_t should be stored.

 

Returns

0 on timeout, a negative value on error, 1 on success.


prelude_client_destroy ()

void
prelude_client_destroy (prelude_client_t *client,
                        prelude_client_exit_status_t status);

Destroy client , and send an heartbeat containing the 'exiting' status in case status is PRELUDE_CLIENT_EXIT_STATUS_SUCCESS.

This is useful for analyzer expected to be running periodically, and that shouldn't be treated as behaving anormaly in case no heartbeat is sent.

Please note that your are not supposed to run this function from a signal handler.

Parameters

client

Pointer on a client object.

 

status

Exit status for the client.

 

prelude_client_set_flags ()

int
prelude_client_set_flags (prelude_client_t *client,
                          prelude_client_flags_t flags);

Set specific flags in the client structure. This function can be called anytime after the creation of the client object.

When settings asynchronous flags such as PRELUDE_CLIENT_FLAGS_ASYNC_SEND or PRELUDE_CLIENT_FLAGS_ASYNC_TIMER, be carefull to call prelude_client_set_flags() in the same process you want to use the asynchronous API from. Threads aren't copied accross fork().

Parameters

client

Pointer on a prelude_client_t object.

 

flags

Or'd list of flags used by client .

 

Returns

0 if setting flags succeed, -1 otherwise.


prelude_client_set_config_filename ()

int
prelude_client_set_config_filename (prelude_client_t *client,
                                    const char *filename);

The default for a client is to use a template configuration file (idmef-client.conf). By using this function you might override the default and provide your own configuration file to use for client . The format of the configuration file need to be compatible with the Prelude format.

Parameters

client

pointer on a prelude_client_t object.

 

filename

Configuration file to use for this client.

 

Returns

0 on success, -1 if an error occured.


prelude_client_get_config_filename ()

const char *
prelude_client_get_config_filename (prelude_client_t *client);

Return the filename where client configuration is stored. This filename is originally set by the prelude_client_new() function.

Parameters

client

pointer on a prelude_client_t object.

 

Returns

a pointer to client configuration filename.


prelude_client_is_setup_needed ()

prelude_bool_t
prelude_client_is_setup_needed (int error);

prelude_client_is_setup_needed is deprecated and should not be used in newly-written code.

use standard error API.

This function should be called as a result of an error by the prelude_client_start() function, to know if the analyzer need to be registered.

Parameters

error

Error returned by prelude_client_start().

 

Returns

TRUE if setup is needed, FALSE otherwise.


prelude_client_get_profile ()

prelude_client_profile_t *
prelude_client_get_profile (prelude_client_t *client);


prelude_client_new_msgbuf ()

int
prelude_client_new_msgbuf (prelude_client_t *client,
                           prelude_msgbuf_t **msgbuf);


prelude_client_handle_msg_default ()

int
prelude_client_handle_msg_default (prelude_client_t *client,
                                   prelude_msg_t *msg,
                                   prelude_msgbuf_t *msgbuf);


prelude_client_get_setup_error ()

const char *
prelude_client_get_setup_error (prelude_client_t *client);

prelude_client_get_setup_error is deprecated and should not be used in newly-written code.


prelude_client_print_setup_error ()

void
prelude_client_print_setup_error (prelude_client_t *client);

Types and Values

enum prelude_client_exit_status_t

Members

PRELUDE_CLIENT_EXIT_STATUS_SUCCESS

   

PRELUDE_CLIENT_EXIT_STATUS_FAILURE

   

enum prelude_client_flags_t

Members

PRELUDE_CLIENT_FLAGS_ASYNC_SEND

   

PRELUDE_CLIENT_FLAGS_ASYNC_TIMER

   

PRELUDE_CLIENT_FLAGS_HEARTBEAT

   

PRELUDE_CLIENT_FLAGS_CONNECT

   

PRELUDE_CLIENT_FLAGS_AUTOCONFIG

   

prelude_client_t

typedef struct prelude_client prelude_client_t;

See Also

idmef_message_t idmef_path_t