.. versionadded:: 2015.5.0

    Fire an event if the minion gets disconnected from its master. This
    function is meant to be run via a scheduled job from the minion. If
    master_ip is an FQDN/Hostname, is must be resolvable to a valid IPv4
    address.

    CLI Example:

    .. code-block:: bash

        salt '*' status.master

def master(master=None, connected=True):
    '''
    .. versionadded:: 2015.5.0

    Fire an event if the minion gets disconnected from its master. This
    function is meant to be run via a scheduled job from the minion. If
    master_ip is an FQDN/Hostname, is must be resolvable to a valid IPv4
    address.

    CLI Example:

    .. code-block:: bash

        salt '*' status.master
    '''

    def _win_remotes_on(port):
        '''
        Windows specific helper function.
        Returns set of ipv4 host addresses of remote established connections
        on local or remote tcp port.

        Parses output of shell 'netstat' to get connections

        PS C:> netstat -n -p TCP

        Active Connections

          Proto  Local Address          Foreign Address        State
          TCP    10.1.1.26:3389         10.1.1.1:4505          ESTABLISHED
          TCP    10.1.1.26:56862        10.1.1.10:49155        TIME_WAIT
          TCP    10.1.1.26:56868        169.254.169.254:80     CLOSE_WAIT
          TCP    127.0.0.1:49197        127.0.0.1:49198        ESTABLISHED
          TCP    127.0.0.1:49198        127.0.0.1:49197        ESTABLISHED
        '''
        remotes = set()
        try:
            data = subprocess.check_output(['netstat', '-n', '-p', 'TCP'])  # pylint: disable=minimum-python-version
        except subprocess.CalledProcessError:
            log.error('Failed netstat')
            raise

        lines = salt.utils.stringutils.to_unicode(data).split('\n')
        for line in lines:
            if 'ESTABLISHED' not in line:
                continue
            chunks = line.split()
            remote_host, remote_port = chunks[2].rsplit(':', 1)
            if int(remote_port) != port:
                continue
            remotes.add(remote_host)
        return remotes

    # the default publishing port
    port = 4505
    master_ips = None

    if master:
        master_ips = _host_to_ips(master)

    if not master_ips:
        return

    if __salt__['config.get']('publish_port') != '':
        port = int(__salt__['config.get']('publish_port'))

    master_connection_status = False
    connected_ips = _win_remotes_on(port)

    # Get connection status for master
    for master_ip in master_ips:
        if master_ip in connected_ips:
            master_connection_status = True
            break

    # Connection to master is not as expected
    if master_connection_status is not connected:
        event = salt.utils.event.get_event('minion', opts=__opts__, listen=False)
        if master_connection_status:
            event.fire_event({'master': master}, salt.minion.master_event(type='connected'))
        else:
            event.fire_event({'master': master}, salt.minion.master_event(type='disconnected'))

    return master_connection_status