func dispatchIncomingPacket() {
for {
packet := network.NextPacket()
// DHCP
if udpLayer := packet.Layer(layers.LayerTypeUDP); udpLayer != nil {
// DHCPv4
if udpLayer.(*layers.UDP).SrcPort == network.Bootps {
appLayer := packet.ApplicationLayer()
if appLayer == nil {
continue
}
macAddr := util.ConvertMax8byteToUint64(packet.Layer(layers.LayerTypeEthernet).(*layers.Ethernet).DstMAC)
if dhcpIn, ok := MapClientsByMac[macAddr]; ok {
dhcpIn <- appLayer.Payload()
}
// next packet
continue
}
if udpLayer.(*layers.UDP).SrcPort == network.Dhcpv6Server {
// TODO DHCPv6
}
}
// ARP
if layer := packet.Layer(layers.LayerTypeARP); layer != nil {
arpLayer := layer.(*layers.ARP)
if arpLayer.Operation != layers.ARPRequest {
continue
}
if arpIn, ok := arp.MapArpByIp.Lookup(arpLayer.DstProtAddress); ok {
arpIn <- arpLayer
}
// next packet
continue
}
}
}
func main() {
var (
paramIfaceName = flag.String("eth", "eth0", "Define on which interface the customer will bind")
paramFirstMacAddr = flag.String("mac", "00:00:13:11:19:77", "First mac address use for the first client (incremented by one for each next clients)")
paramGiADDR = flag.String("giaddr", "10.0.0.1", "Use as GiADDR into DHCPv4 header")
paramNbDhcpClient = flag.Uint("nb_dhcp", 1, "Define number of dhcp client")
paramLogin = flag.String("login", "%08d", "Define what is use into option90. fmt.Printf and index of dhcp client with range [0, nb_dhcp[ is used.")
paramPacing = flag.Duration("pacing", 100*time.Millisecond, "Define the pacing for launch new dhcp client")
paramNoLogin = flag.Bool("noLogin", false, "No login (DHCPv4: option 90)")
paramNoRelay = flag.Bool("noRelay", false, "No relay")
)
flag.Parse()
dhcp4.DhcRelay = !*paramNoRelay
dhcp4.Option90 = !*paramNoLogin
firstMacAddr, err := net.ParseMAC(*paramFirstMacAddr)
if err != nil {
log.Fatal(err)
}
giaddr, err := util.ConvertIpAddrToUint32(*paramGiADDR)
if err != nil {
log.Fatal(err)
}
if err = network.OpenPcapHandle(*paramIfaceName, fmt.Sprintf("arp or port %v", network.Bootps)); err != nil {
log.Fatal(err)
}
defer network.Close()
go func() {
if err := http.ListenAndServe(":6060", nil); err != nil {
log.Println(err)
}
}()
intFirstMacAddr := util.ConvertMax8byteToUint64(firstMacAddr)
macAddr := make([]byte, 8)
util.ConvertUint64To8byte(intFirstMacAddr+uint64(*paramNbDhcpClient)-1, macAddr)
log.Println("First : Mac Addr", firstMacAddr, "- login", fmt.Sprintf(*paramLogin, 0))
log.Println("Last : Mac Addr", net.HardwareAddr(macAddr[2:]), "- login", fmt.Sprintf(*paramLogin, *paramNbDhcpClient-1))
rand.Seed(time.Now().UTC().UnixNano())
{
var listRunnable = make([]runnable, 0, *paramNbDhcpClient)
// Create each DhcpClient
for i := 0; i < int(*paramNbDhcpClient); i++ {
macAddr := make([]byte, 8)
util.ConvertUint64To8byte(intFirstMacAddr+uint64(i), macAddr)
// Reduce the byte array, as mac addr is only on 6 bytes with BigEndian format
macAddr = macAddr[2:]
dhcpClient, dhcpIn := dhcp4.CreateClient(macAddr, giaddr, fmt.Sprintf(*paramLogin, i))
log.Println("DhcpClient created:", dhcpClient)
MapClientsByMac[intFirstMacAddr+uint64(i)] = dhcpIn
listRunnable = append(listRunnable, dhcpClient)
}
// Listen all incoming packets
go dispatchIncomingPacket()
// Launch each DhcpClient (DORA and so on)
for i := range listRunnable {
listRunnable[i].Run()
time.Sleep(*paramPacing)
}
}
// Block main goroutine
select {}
}