sniff-mac.go

package mac

import (
	"fmt"
	"network-chesswork/utilities"
	"time"

	"github.com/google/gopacket"
	"github.com/google/gopacket/layers"
	"github.com/google/gopacket/pcap"
)

func Sniff(iface string) error {
	if iface == "" {
		return fmt.Errorf("network interface is required")
	} else {
		fmt.Println("Sniffing package received interface", iface)
	}

	// Open the network interface for packet capture
	handle, err := pcap.OpenLive(iface, 1600, true, pcap.BlockForever)

	if err != nil {
		return fmt.Errorf("failed to open live capture: %w", err)
	}

	defer handle.Close()

	packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
	macAddresses := make(map[string]bool)

	for packet := range packetSource.Packets() {
		// Extract Ethernet layer
		ethernetLayer := packet.Layer(layers.LayerTypeEthernet)
		if ethernetLayer == nil {
			continue
		}

		ethernetPacket, ok := ethernetLayer.(*layers.Ethernet)
		if !ok {
			continue
		}

		srcMAC := ethernetPacket.SrcMAC.String()
		dstMAC := ethernetPacket.DstMAC.String()

		if !macAddresses[srcMAC] {
			macAddresses[srcMAC] = true
			fmt.Println("Source MAC Address:", srcMAC)
			path := "./temp/source-mac.json"

			data := map[string]interface{}{
				srcMAC: map[string]interface{}{
					"time": time.Now().UTC().Format(time.RFC3339),
				},
			}
			if err := utilities.AppendJSON(path, data); err != nil {
				return fmt.Errorf("failed to append source MAC address to JSON: %w", err)
			}
		}

		if !macAddresses[dstMAC] {
			macAddresses[dstMAC] = true
			fmt.Println("Destination MAC Address:", dstMAC)
			path := "./temp/dest-mac.json"

			data := map[string]interface{}{
				dstMAC: map[string]interface{}{
					"time": time.Now().UTC().Format(time.RFC3339),
				},
			}
			if err := utilities.AppendJSON(path, data); err != nil {
				return fmt.Errorf("failed to append destination MAC address to JSON: %w", err)
			}
		}
	}

	return nil
}