slimming/main.go

package main

import (
	"encoding/binary"
	"flag"
	"fmt"
	"log"
	"net"
	"os/exec"
	"strings"

	"github.com/songgao/packets/ethernet"
	"github.com/songgao/water"
)

func init() {
	log.SetFlags(log.Llongfile | log.LstdFlags)
}

//go:generate bash -c "protoc --go_out=plugins=grpc:. proto/*.proto"
func main() {
	testmain()
	// NewNetCard().Run()
}

var (
	flagAddr = flag.String("addr", "", "addr set")
)

func startCard() {
	cmdstr := fmt.Sprintf("ip addr add %s dev stun", *flagAddr)
	log.Println(cmdstr)
	cmd := strings.Split(cmdstr, " ")
	err := exec.Command(cmd[0], cmd[1:]...).Run()
	if err != nil {
		log.Panic(err)
	}

	cmdstr = "ip link set dev stun up"
	cmd = strings.Split(cmdstr, " ")
	err = exec.Command(cmd[0], cmd[1:]...).Run()
	if err != nil {
		log.Panic(err)
	}
}
func testmain() {

	flag.Parse()

	config := water.Config{
		DeviceType: water.TAP,
	}
	config.Name = "stun"

	ifce, err := water.New(config)
	if err != nil {
		log.Fatal(err)
	}

	startCard()

	var frame ethernet.Frame
	for {

		frame.Resize(1500)
		n, err := ifce.Read([]byte(frame))
		if err != nil {
			log.Fatal(err)
		}
		frame = frame[:n]

		if frame.Ethertype() == ethernet.ARP || frame.Ethertype() == ethernet.AARP {

			log.Println(binary.BigEndian.Uint16(frame[20:22]), net.IP(frame[28:32]).To4(), net.HardwareAddr(frame[22:28]), net.IP(frame[38:42]).To4(), net.HardwareAddr(frame[32:38]))

			binary.BigEndian.PutUint16(frame[20:22], 2)
			copy(frame[32:38], frame[22:28])

			log.Println(binary.BigEndian.Uint16(frame[20:22]), net.IP(frame[28:32]).To4(), net.HardwareAddr(frame[22:28]), net.IP(frame[38:42]).To4(), net.HardwareAddr(frame[32:38]))
			log.Printf("type: % x src %s dst %s len %d", frame.Ethertype(), frame.Source(), frame.Destination(), len(frame))
			ifce.Write(frame)
		}

		// if waterutil.IsIPv4(frame) && strings.HasPrefix(waterutil.IPv4Destination(frame).String(), "10.10") {

		// 	log.Printf("Src: %s(%d) Dst: %s(%d) \n", waterutil.IPv4Source(frame), waterutil.IPv4SourcePort(frame), waterutil.IPv4Destination(frame), waterutil.IPv4DestinationPort(frame))

		// 	waterutil.SetIPv4Destination(frame, waterutil.IPv4Source(frame))
		// 	// ifce.Write(frame)
		// 	// log.Printf("DstPort: %d SrcPort: %d\n", (uint16(payload[2])<<8)|uint16(payload[3]), (uint16(payload[0])<<8)|uint16(payload[1]))

		// }

		// log.Printf("Payload: % x\n", frame.Payload())

	}
}