TransitFilter README

Goal: Divide flows into transit and nontransit flows, each on separate output interface.

Method: On the basis of prefixes of CESNET organizations, determine incoming/outgoing
        flows to/from CESNET and divide them from flows whose source or destination
        is not within CESNET.
        Prefixes of CESNET organizations are loaded from file which is specified on
        command line as first and only parameter (except parameters for libtrap).

Input interface: Unirec containing at least:
                 - Source address      (SRC_IP)
                 - Destination addres  (DST_IP)
                 - Link number         (LINK_BIT_FIELD)
                 - Flow direction      (DIR_BIT_FIELD)
Default Unirec used for input interface is <COLLECTOR_FLOW>.

Output interface: 2x Unirec containing same items as input Unirec.
                  1. Interface provides non-transit flows.
                  2. Interface provides transit flows.

Structure of file with network prefixes:
       - Each line contains one network in format: network_address/network_mask
       - Examples: 143.102.0.0/14
                   187.25.32.0/20
                   2001:710:2::/48
                   2001:67d:1210::/48

Algorithm: Binary search algorithm is used for determining if flow is transit or not.
