func gatherPacketLayersInfo(event common.MapStr, packet gopacket.Packet) {
	// see https://godoc.org/github.com/google/gopacket#hdr-Pointers_To_Known_Layers
	//   Pointers To Known Layers:
	//   During decoding, certain layers are stored in the packet as well-known layer types.
	//   For example, IPv4 and IPv6 are both considered NetworkLayer layers,
	//   while TCP and UDP are both TransportLayer layers.
	//   We support 4 layers, corresponding to the 4 layers of the TCP/IP layering scheme
	//   (roughly anagalous to layers 2, 3, 4, and 7 of the OSI model).
	//   To access these, you can use the:
	//     packet.LinkLayer,
	//     packet.NetworkLayer,
	//     packet.TransportLayer, and
	//     packet.ApplicationLayer functions.
	//   Each of these functions returns a corresponding interface (gopacket.{Link,Network,Transport,Application}Layer).
	//   The first three provide methods for getting src/dst addresses for that particular layer,
	//   while the final layer provides a Payload function to get payload data.

	// use "packet.Dump()" as a fail-safe to capture all available layers for a packet,
	// just in case we encounter something unexpected in the unified2 file or we
	// have neglected to handle a particular layer explicitly
	event["packet_dump"] = packet.Dump()
	// "packet.Dump()" is very verbose, i.e. a large amount of text, but that's ok

	// capture the name of the layers found
	var packet_layers []string
	for _, layer := range packet.Layers() {
		packet_layers = append(packet_layers, fmt.Sprintf("%v", layer.LayerType()))
	}
	event["packet_layers"] = packet_layers

	// Ethernet layer?
	ethernetLayer := packet.Layer(layers.LayerTypeEthernet)
	if ethernetLayer != nil {
		ethernetPacket, _ := ethernetLayer.(*layers.Ethernet)
		event["ethernet_src_mac"] = fmt.Sprintf("%v", ethernetPacket.SrcMAC)
		event["ethernet_dst_mac"] = fmt.Sprintf("%v", ethernetPacket.DstMAC)
		// ethernet type is typically IPv4 but could be ARP or other
		event["ethernet_type"] = fmt.Sprintf("%v", ethernetPacket.EthernetType)
		// Length is only set if a length field exists within this header.  Ethernet
		// headers follow two different standards, one that uses an EthernetType, the
		// other which defines a length the follows with a LLC header (802.3).  If the
		// former is the case, we set EthernetType and Length stays 0.  In the latter
		// case, we set Length and EthernetType = EthernetTypeLLC.
		event["ethernet_length"] = fmt.Sprintf("%v", ethernetPacket.Length)
	}

	// IPv4 layer?
	ipLayer := packet.Layer(layers.LayerTypeIPv4)
	if ipLayer != nil {
		ip, _ := ipLayer.(*layers.IPv4)
		event["ip_version"] = ip.Version
		event["ip_ihl"] = ip.IHL
		event["ip_tos"] = ip.TOS
		event["ip_length"] = ip.Length
		event["ip_id"] = ip.Id
		event["ip_flags"] = ip.Flags
		event["ip_fragoffset"] = ip.FragOffset
		event["ip_ttl"] = ip.TTL
		event["ip_protocol"] = ip.Protocol
		event["ip_checksum"] = ip.Checksum
		event["ip_src_ip"] = ip.SrcIP
		event["ip_dst_ip"] = ip.DstIP
		event["ip_options"] = ip.Options // maybe? fmt.Sprintf("%v", ip.Options)
		event["ip_padding"] = ip.Padding
	}

	// IPv6 layer?
	ip6Layer := packet.Layer(layers.LayerTypeIPv6)
	if ip6Layer != nil {
		ip6, _ := ip6Layer.(*layers.IPv6)
		event["ip6_version"] = ip6.Version
		event["ip6_trafficclass"] = ip6.TrafficClass
		event["ip6_flowlabel"] = ip6.FlowLabel
		event["ip6_length"] = ip6.Length
		event["ip6_nextheader"] = ip6.NextHeader
		event["ip6_hoplimit"] = ip6.HopLimit
		event["ip6_src_ip"] = ip6.SrcIP
		event["ip6_dst_ip"] = ip6.DstIP
		event["ip6_hopbyhop"] = ip6.HopByHop
	}

	// see: gopacket/layers folder ... what layers are needed for Snort/Suricata alerts?
	// ICMPv4 layer?
	// ICMPv6 layer?
	// ARP layer?

	// UDP layer?
	udpLayer := packet.Layer(layers.LayerTypeUDP)
	if udpLayer != nil {
		udp, _ := udpLayer.(*layers.UDP)
		event["udp_src_port"] = udp.SrcPort
		event["udp_dst_port"] = udp.DstPort
		event["udp_length"] = udp.Length
		event["udp_checksum"] = udp.Checksum
	}

	// TCP layer?
	tcpLayer := packet.Layer(layers.LayerTypeTCP)
	if tcpLayer != nil {
		tcp, _ := tcpLayer.(*layers.TCP)
		event["tcp_src_port"] = tcp.SrcPort
		event["tcp_dst_port"] = tcp.DstPort
		event["tcp_seq"] = tcp.Seq
		event["tcp_ack"] = tcp.Ack
		event["tcp_data_offset"] = tcp.DataOffset
		event["tcp_fin"] = tcp.FIN
		event["tcp_syn"] = tcp.SYN
		event["tcp_rst"] = tcp.RST
		event["tcp_psh"] = tcp.PSH
		event["tcp_ack"] = tcp.ACK
		event["tcp_urg"] = tcp.URG
		event["tcp_ece"] = tcp.ECE
		event["tcp_cwr"] = tcp.CWR
		event["tcp_ns"] = tcp.NS
		event["tcp_window"] = tcp.Window
		event["tcp_checksum"] = tcp.Checksum
		event["tcp_urgent"] = tcp.Urgent
		event["tcp_options"] = tcp.Options // maybe? fmt.Sprintf("%v", tcp.Options)
		event["tcp_padding"] = tcp.Padding
	}

	// note: the Payload layer is the same as this applicationLayer
	// also, we can get payloads for all packets regardless of their underlying data type:
	// application layer? (aka packet payload)
	applicationLayer := packet.ApplicationLayer()
	if applicationLayer != nil {
		event["packet_payload"] = fmt.Sprintf("%s", applicationLayer.Payload())
	}

	// errors?
	if err := packet.ErrorLayer(); err != nil {
		event["packet_error"] = fmt.Sprintf("Packet decoding error: %v", err)
	}
}