func main() {
log.SetFlags(0)
usage := `Usage: arp <addr>
Resolve the given IP address using ARP.`
args, err := docopt.Parse(usage, nil, true, "", false)
if err != nil {
log.Fatalf("Invalid arguments: %s", err)
}
addr := args["<addr>"].(string)
addr_ip := net.ParseIP(addr)
timeout := 5 * time.Second
route, err := routing.RouteTo(addr_ip)
if err != nil {
log.Fatalf("Error: %s", err)
}
if route == nil {
log.Println("No route found")
}
c, err := pcap.Open(route.Iface.Name)
if err != nil {
log.Fatalf("Error opening interface: %s", err)
}
defer c.Close()
err = c.Activate()
if err != nil {
log.Fatalf("Error activating source: %s", err)
}
eth_pkt := eth.Make()
eth_pkt.SrcAddr = route.Iface.HardwareAddr
eth_pkt.DstAddr, _ = net.ParseMAC("ff:ff:ff:ff:ff:ff")
arp_pkt := arp.Make()
arp_pkt.HWSrcAddr = route.Iface.HardwareAddr
arp_pkt.HWDstAddr, _ = net.ParseMAC("00:00:00:00:00:00")
arp_pkt.ProtoSrcAddr, _ = route.GetIfaceIPv4Addr()
arp_pkt.ProtoDstAddr = addr_ip
pkt, err := network.SendRecv(c, timeout, eth_pkt, arp_pkt)
if err != nil {
log.Fatal(err)
}
log.Println(pkt.Payload().(*arp.Packet).HWSrcAddr)
}
func ResolveARP(c capture.Handle, t time.Duration, r *routing.Route, addr net.IP) net.HardwareAddr {
eth_pkt := eth.Make()
eth_pkt.SrcAddr = r.Iface.HardwareAddr
eth_pkt.DstAddr, _ = net.ParseMAC("ff:ff:ff:ff:ff:ff")
arp_pkt := arp.Make()
arp_pkt.HWSrcAddr = r.Iface.HardwareAddr
arp_pkt.HWDstAddr, _ = net.ParseMAC("00:00:00:00:00:00")
arp_pkt.ProtoSrcAddr, _ = r.GetIfaceIPv4Addr()
arp_pkt.ProtoDstAddr = addr
pkt, err := network.SendRecv(c, t, eth_pkt, arp_pkt)
if err != nil {
log.Fatal(err)
}
return pkt.Payload().(*arp.Packet).HWSrcAddr
}
func TestPackEthArp(t *testing.T) {
eth_pkt := eth.Make()
eth_pkt.SrcAddr, _ = net.ParseMAC(hwsrc_str)
eth_pkt.DstAddr, _ = net.ParseMAC("ff:ff:ff:ff:ff:ff")
arp_pkt := arp.Make()
arp_pkt.HWSrcAddr, _ = net.ParseMAC(hwsrc_str)
arp_pkt.HWDstAddr, _ = net.ParseMAC("00:00:00:00:00:00")
arp_pkt.ProtoSrcAddr = net.ParseIP(ipsrc_str)
arp_pkt.ProtoDstAddr = net.ParseIP(ipdst_str)
buf, err := layers.Pack(eth_pkt, arp_pkt)
if err != nil {
t.Fatalf("Error packing: %s", err)
}
if !bytes.Equal(test_eth_arp, buf) {
t.Fatalf("Raw packet mismatch: %x", buf)
}
}
func ExamplePack() {
// Create an Ethernet packet
eth_pkt := eth.Make()
eth_pkt.SrcAddr, _ = net.ParseMAC("4c:72:b9:54:e5:3d")
eth_pkt.DstAddr, _ = net.ParseMAC("ff:ff:ff:ff:ff:ff")
// Create an ARP packet
arp_pkt := arp.Make()
arp_pkt.HWSrcAddr, _ = net.ParseMAC("4c:72:b9:54:e5:3d")
arp_pkt.HWDstAddr, _ = net.ParseMAC("00:00:00:00:00:00")
arp_pkt.ProtoSrcAddr = net.ParseIP("192.168.1.135")
arp_pkt.ProtoDstAddr = net.ParseIP("192.168.1.254")
buf, err := layers.Pack(eth_pkt, arp_pkt)
if err != nil {
log.Fatal(err)
}
// do something with the packet
log.Println(buf)
}