Modify goflow2 to add TimeFlowStartMs and TimeFlowEndMs

[ghost]

As proposed in https://github.com/netsampler/goflow2/issues/78 instead of modifying the FIRST_SWITCHED and LAST_SWITCHED is a better option to create new features:

• TimeFlowStartMs

• TimeFlowEndMs So it would not break any of the current implementations. First analyze the problem and see if it is feasable

• [x] Make modifications on goflow2 to include those fields

• [x] Create image from Dockerfile in SDA or goflow2 repo? -> Irrelevant as arguments are configured in the kubernetes template

• [x] Use tcpdump to capture netflow traffic from softlow (192.168.165.138)

• [x] Use tcpreplay to replay the captured traffic to do tests with goflow2

• [x] Test modifcations on goflow2 are working

• [x] Change modifications for other Netflow versions (v5, v9, v10)

• [x] Make pull request

DOCUMENTATION

• Contribute to a OpenSource project

[ghost]

Instead of using tcpreplay to send the traffic it can be used softflowd to read from a pcap file using the "-r" argument.

To use netflow v9 with goflow2:

  goflow2:
      build:
        context: ./docker/goflow2
        dockerfile: Dockerfile
      hostname: goflow2
      container_name: goflow2
      ports:
        - 9995:9995/udp
      depends_on:
        - kafka
      restart: always
      command:
      - -transport=kafka
      - -transport.kafka.brokers=kafka:9092
      - -transport.kafka.topic=flows
      - -format=json
      - -listen=nfl://:9995 # to use netflow v5
#      - -listen=netflow://:9995 # to use netflow v9 or v10 (IPFIX)

[ghost]

Pull merged in: https://github.com/netsampler/goflow2/pull/81