This test aims for testing the typical use of the internet checksum algorithms
provided with the net library. It is accompanied by a similarly named test
script.

The test script feeds the test component with a sufficiently big input.pcap
file that is randomly generated on each run using trafgen. The test component
then iterates over all packets in the file. For each found IPv4, UDP, TCP or
ICMP header (except the embedded ones in ICMP errors), it typically does the
following:

  1. try to validate the initial checksum
  2. try to re-calculate the initial checksum and see if it stas the same
  3. modify the header randomly, update the checksum incrementally, and write
     out the result to a file output.pcap

The checksums in the resulting output.pcap file are then checked by the test
script using tshark. On each run, the test script prints the seed used for
randomization in both, the test component and trafgen. In order to reproduce a
given test result, one can simply run the test script with SEED=<seed>.
