func()

in pcap-cli/internal/transformer/json_translator.go [269:324]

• 42 lines of code
• 3 McCabe index (conditional complexity)

func (t *JSONPcapTranslator) translateIPv4Layer(
	ctx context.Context,
	ip4 *layers.IPv4,
) fmt.Stringer {
	json := gabs.New()

	// https://github.com/google/gopacket/blob/master/layers/ip4.go#L43

	L3, _ := json.Object("L3")

	L3.Set(ip4.Version, "v")
	L3.Set(ip4.SrcIP, "src")
	L3.Set(ip4.DstIP, "dst")
	L3.Set(ip4.Id, "id")
	L3.Set(ip4.IHL, "ihl")
	L3.Set(ip4.TTL, "ttl")
	L3.Set(ip4.TOS, "tos")
	L3.Set(ip4.Length, "len")
	L3.Set(ip4.FragOffset, "foff")
	L3.Set(ip4.Checksum, "xsum")

	proto, _ := L3.Object("proto")
	proto.Set(ip4.Protocol, "num")

	if sizeOfOptions := len(ip4.Options); sizeOfOptions > 0 {
		opts, _ := L3.ArrayOfSize(sizeOfOptions, "opts")
		for i, opt := range ip4.Options {
			o, _ := opts.ObjectI(i)
			o.Set(string(opt.OptionData), "data")
			o.Set(opt.OptionType, "type")
		}
	}

	// hashing bytes yields `uint64`, and addition is commutative:
	//   - so hashing the IP byte array representations and then adding then resulting `uint64`s is a commutative operation as well.
	flowID := fnv1a.HashUint64(uint64(4) + fnv1a.HashBytes64(ip4.SrcIP.To4()) + fnv1a.HashBytes64(ip4.DstIP.To4()))
	flowIDstr := strconv.FormatUint(flowID, 10)
	L3.Set(flowIDstr, "flow") // IPv4(4) (0x04)

	atDebugVerbosity(ctx,
		t.pcapTranslator,
		func(
			ctx context.Context,
			translator *pcapTranslator,
		) {
			proto.Set(ip4.Protocol.String(), "name")

			// https://github.com/google/gopacket/blob/master/layers/ip4.go#L28-L40
			L3.Set(strings.Split(ip4.Flags.String(), "|"), "flags")

			networkFlow := ip4.NetworkFlow()
			t.addEndpoints(L3, &networkFlow)
		})

	return json
}