asterisk_monitor() {
    local rc

    asterisk_status
    rc=$?

    # If status returned an error, return that immediately
    if [ $rc -ne $OCF_SUCCESS ]; then
        return $rc
    fi

    # Check whether connecting to asterisk is possible
    asterisk_rx 'core show channels count'
    rc=$?

    if [ $rc -ne 0 ]; then
      ocf_log err "Failed to connect to the Asterisk PBX"
      return $OCF_ERR_GENERIC
    fi

    # Optionally check the monitor URI with sipsak
    # The return values:
    # 0 means that a 200 was received.
    # 1 means something else then 1xx or 2xx was received.
    # 2 will be returned on local errors like non resolvable names
    #   or wrong options combination.
    # 3 will be returned on remote errors like socket errors
    #   (e.g. icmp error), redirects without a contact header or
    #   simply no answer (timeout).
    #   This can also happen if sipsak is run too early after asterisk
    #   start.
    if [ -n "$OCF_RESKEY_monitor_sipuri" ]; then
        ocf_run sipsak -s "$OCF_RESKEY_monitor_sipuri"
        rc=$?
        case "$rc" in
          1|2) return $OCF_ERR_GENERIC;;
          3)   return $OCF_NOT_RUNNING;;
        esac
    fi

    ocf_log debug "Asterisk PBX monitor succeeded"
    return $OCF_SUCCESS
}