eap_pcap.go

package main

import (
    "fmt"
    "github.com/google/gopacket"
    "github.com/google/gopacket/pcap"
    "github.com/google/gopacket/layers"
    "log"
)

const etherTypeEap uint16 = 0x888E

var (
    handle *pcap.Handle
    err error
)

func main() {
    handle, err = pcap.OpenOffline("eap.pcap")
    if err != nil {
        log.Fatal("unable to open pcap file")
    }
    defer handle.Close()

    packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
    for packet := range packetSource.Packets() {
        printPacketInfo(packet)
    }
}

func printPacketInfo(packet gopacket.Packet) {
    ethernetLayer := packet.Layer(layers.LayerTypeEthernet)
    eapolLayer := packet.Layer(layers.LayerTypeEAPOL)

    // Let's see if the packet is an ethernet packet
    if ethernetLayer == nil {
        fmt.Println("skipping packet")
        return
    }
    ethernetPacket, _ := ethernetLayer.(*layers.Ethernet)

    // Let's see if we have an EAPOL Packet
    if eapolLayer == nil {
        fmt.Println("Not an EAP packet, skipping...")
        return
    }
    eapol, _ := eapolLayer.(*layers.EAPOL)
    fmt.Printf("%s: %s v%d, len %d", ethernetPacket.SrcMAC, eapol.Type, eapol.Version, eapol.Length)

    fmt.Println()
}

func EAPTypeString(code layers.EAPCode) string {
    switch code {
    case 1:
        return "Request"
    case 2:
        return "Response"
    case 3:
        return "Success"
    case 4:
        return "Failure"
    }
    return "Unknown"
}