=head1 NAME

librouteros - Library for accessing MikroTik's RouterOS via its API

=head1 DESCRIPTION

B<librouteros> is a library to communicate with I<RouterOS>, the operating
system of I<MikroTik's> I<RouterBoards>. It uses the "API port" provided by
those systems to connect and talk to the devices. librouteros is a low-level
library in that it abstracts the network protocol used but has next to no
knowledge about the commands and responses available. Should such an high-level
interface prove useful, it will be added as the need arises.

=head1 GENERAL USAGE

The interface of librouteros is designed to be lightweight and simple to use.
The first thing when using the library is to create a connection object. Once a
connection has been established and logging in succeeded, queries can be sent
to the remote device. The library will encode and send the request, read back a
reply, decode it and pass it to a callback function. The callback function has
access to the parsed reply and can easily access all parts and parameters. It
does not need to worry about memory management because everything provided to
it will be freed by the library before returning to where the query was called
from. When the application is done talking to the device and disconnects, the
connection object will be freed.

=head1 DATA TYPES

The following data types are used and returned by librouteros:

=over 4

=item B<ros_connection_t>

The "connection object" represents the connection to one device.
This is an opaque data type, meaning that you can only have pointers to such
objects but not dereference or manipulate them directly.

=item B<ros_reply_t>

One part of a reply (which are stored as a list) received from a device. The
head of the list (the first part) is passed to the callback function.
This is an opaque data type, meaning that you can only have pointers to such
objects but not dereference or manipulate them directly.

=item B<ros_reply_handler_t>

Convenience data type for the callback functions. Callback functions must have
the following prototype:

  int callback (ros_connection_t *c, const ros_reply_t *r, void *user_data);

The first and second arguments are objects representing the connection and the
reply respectively. I<user_data> is a pointer as passed to B<ros_query> (see
below).

The value returned by the callback function will be returned by B<ros_query> to
the calling code. To distinguish from error codes returned by B<ros_query> upon
errors, use negative values in the callback function.

=back

=head1 FUNCTIONS

The following functions are part of librouteros' API and exported. Functions
not listed here are not part of the API, should not be exported and may change
and disappear at any time. Please report such functions are bugs.

=over 4

=item ros_connection_t *B<ros_connect> (const char *I<node>, const char *I<service>, const char *I<username>, const char *I<password>)

Connects to the remote device using I<node> as the address or hostname. If
I<service> is C<NULL>, the standard port B<8728> will be used. When a
connection has been established, the library will try to authenticate using
I<username> and I<password>.

On failure, C<NULL> is returned and B<errno> is set appropriately.

=item int B<ros_disconnect> (ros_connection_t *I<c>)

Disconnects from the device and frees all memory associated with the
connection. After this call, I<c> may not be used anymore.

Returns zero upon success and an error code otherwise.

=item int B<ros_query> (ros_connection_t *I<c>, const char *I<command>, size_t I<args_num>, const char * const *I<args>, ros_reply_handler_t I<handler>, void *I<user_data>)

Sends the command I<command> with the I<args_num> arguments I<args> via the
connection I<c> and reads back the reply. The reply is parsed and passed to the
callback function I<handler>. I<user_data> is a pointer passed through to the
callback function. Please note that the callback function is called only once,
even if the reply consists of multiple parts. Use the B<ros_reply_next>
function (see below) to access the other parts.

Returns the value returned by the callback function upon success and an error
code otherwise.

=item const ros_reply_t *B<ros_reply_next> (const ros_reply_t *I<r>)

Each reply can consist of several parts or "sentences". If there is more than
one sentence returned by the device, this function will return the next part.
When the end of the list is reached, C<NULL> is returned.

=item int B<ros_reply_num> (const ros_reply_t *I<r>)

Returns the number of replies in the list pointed to by and including I<r>.

=item const char *B<ros_reply_status> (const ros_reply_t *I<r>)

Returns the status message of this part or reply. This is usually "re" for data
parts, "done" for the last part in a reply and "trap" for errors.
The returned pointer must not be freed.

=item const char *B<ros_reply_param_key_by_index> (const ros_reply_t *I<r>, unsigned int I<index>)

Returns the parameter key at index I<index> (starting with zero) of reply I<r>.
If I<index> is out of bounds, returns C<NULL>.
The returned pointer must not be freed.

=item const char *B<ros_reply_param_val_by_index> (const ros_reply_t *I<r>, unsigned int I<index>)

Returns the parameter value at index I<index> (starting with zero) of reply
I<r>. If I<index> is out of bounds, returns C<NULL>.
The returned pointer must not be freed.

=item const char *ros_reply_param_val_by_key (const ros_reply_t *r, const char *key)

Returns the parameter value corresponding to key I<key> (or C<NULL> if there is
no such key) of reply I<r>.
The returned pointer must not be freed.

=back

=head1 ERROR HANDLING

Some of the functions above return an "error code". This error code can be
transferred to a string describing the error using L<strerror(3)> or
L<strerror_r(3)>. Since the error codes are all positive integers, it is
recommended to use negative return values in the callback functions to indicate
custom errors if appropriate.

=head1 THREAD SAFETY

librouteros uses only thread-safe functions and does not store any global data
itself. It is therefore fully thread and reentrant safe as long as you don't
call any functions with the same connection object.

=head1 LICENSE

librouteros is licensed under the GPLv2. No other version of the license is
applicable.

=head1 AUTHOR

librouteros is written by Florian octo Forster E<lt>octo at verplant.orgE<gt>.
It's homepage can be found at L<http://verplant.org/librouteros/>.

(c) 2009 by Florian octo Forster.