开坑UDP

cmd/udp/main.go

@@ -0,0 +1,167 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"net"
+	"netstack/tcpip"
+	"netstack/tcpip/link/fdbased"
+	"netstack/tcpip/link/tuntap"
+	"netstack/tcpip/network/arp"
+	"netstack/tcpip/network/ipv4"
+	"netstack/tcpip/network/ipv6"
+	"netstack/tcpip/stack"
+	"netstack/tcpip/transport/udp"
+	"netstack/waiter"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var mac = flag.String("mac", "01:01:01:01:01:01", "mac address to use in tap device")
+
+func main() {
+	flag.Parse()
+	if len(flag.Args()) != 3 {
+		log.Fatal("Usage: ", os.Args[0], " <tap-device> <listen-address> port")
+	}
+
+	log.SetFlags(log.Lshortfile | log.LstdFlags)
+	tapName := flag.Arg(0)
+	listeAddr := flag.Arg(1)
+	portName := flag.Arg(2)
+
+	log.Printf("tap: %v, listeAddr: %v, portName: %v", tapName, listeAddr, portName)
+
+	// Parse the mac address.
+	maddr, err := net.ParseMAC(*mac)
+	if err != nil {
+		log.Fatalf("Bad MAC address: %v", *mac)
+	}
+
+	parsedAddr := net.ParseIP(listeAddr)
+
+	// 解析地址ip地址，ipv4或者ipv6地址都支持
+	var addr tcpip.Address
+	var proto tcpip.NetworkProtocolNumber
+	if parsedAddr.To4() != nil {
+		addr = tcpip.Address(parsedAddr.To4())
+		proto = ipv4.ProtocolNumber
+	} else if parsedAddr.To16() != nil {
+		addr = tcpip.Address(parsedAddr.To16())
+		proto = ipv6.ProtocolNumber
+	} else {
+		log.Fatalf("Unknown IP type: %v", parsedAddr)
+	}
+
+	localPort, err := strconv.Atoi(portName)
+	if err != nil {
+		log.Fatalf("Unable to convert port %v: %v", portName, err)
+	}
+
+	// 虚拟网卡配置
+	conf := &tuntap.Config{
+		Name: tapName,
+		Mode: tuntap.TAP,
+	}
+
+	var fd int
+	// 新建虚拟网卡
+	fd, err = tuntap.NewNetDev(conf)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// 启动tap网卡
+	_ = tuntap.SetLinkUp(tapName)
+	// 设置tap网卡IP地址
+	_ = tuntap.AddIP(tapName, listeAddr)
+
+	// 抽象网卡的文件接口
+	linkID := fdbased.New(&fdbased.Options{
+		FD:      fd,
+		MTU:     1500,
+		Address: tcpip.LinkAddress(maddr),
+	})
+
+	// 新建相关协议的协议栈
+	s := stack.New([]string{ipv4.ProtocolName, arp.ProtocolName},
+		[]string{ /*tcp.ProtocolName, */ udp.ProtocolName}, stack.Options{})
+
+	// 新建抽象的网卡
+	if err := s.CreateNamedNIC(1, "vnic1", linkID); err != nil {
+		log.Fatal(err)
+	}
+
+	// 在该协议栈上添加和注册相应的网络层
+	if err := s.AddAddress(1, proto, addr); err != nil {
+		log.Fatal(err)
+	}
+
+	// 在该协议栈上添加和注册ARP协议
+	if err := s.AddAddress(1, arp.ProtocolNumber, arp.ProtocolAddress); err != nil {
+		log.Fatal(err)
+	}
+
+	// 添加默认路由
+	s.SetRouteTable([]tcpip.Route{
+		{
+			Destination: tcpip.Address(strings.Repeat("\x00", len(addr))),
+			Mask:        tcpip.AddressMask(strings.Repeat("\x00", len(addr))),
+			Gateway:     "",
+			NIC:         1,
+		},
+	})
+
+	// 同时监听tcp和udp localPort端口
+	//tcpEp := tcpListen(s, proto, localPort)
+	udpEp := udpListen(s, proto, localPort)
+	// 关闭监听服务，此时会释放端口
+	//tcpEp.Close()
+	udpEp.Close()
+}
+
+//func tcpListen(s *stack.Stack, proto tcpip.NetworkProtocolNumber, localPort int) tcpip.Endpoint {
+//	var wq waiter.Queue
+//	// 新建一个tcp端
+//	ep, err := s.NewEndpoint(tcp.ProtocolNumber, proto, &wq)
+//	if err != nil {
+//		log.Fatal(err)
+//	}
+//
+//	// 绑定IP和端口，这里的IP地址为空，表示绑定任何IP
+//	// 此时就会调用端口管理器
+//	if err := ep.Bind(tcpip.FullAddress{0, "", uint16(localPort)}, nil); err != nil {
+//		log.Fatal("Bind failed: ", err)
+//	}
+//
+//	// 开始监听
+//	if err := ep.Listen(10); err != nil {
+//		log.Fatal("Listen failed: ", err)
+//	}
+//
+//	return ep
+//}
+
+func udpListen(s *stack.Stack, proto tcpip.NetworkProtocolNumber, localPort int) tcpip.Endpoint {
+	var wq waiter.Queue
+	// 新建一个udp端
+	ep, err := s.NewEndpoint(udp.ProtocolNumber, proto, &wq)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// 绑定IP和端口，这里的IP地址为空，表示绑定任何IP
+	// 0.0.0.0:9999 这台机器上的所有ip的9999段端口数据都会使用该传输层实现
+	// 此时就会调用端口管理器
+	if err := ep.Bind(tcpip.FullAddress{NIC: 0, Addr: "", Port: uint16(localPort)}, nil); err != nil {
+		log.Fatal("Bind failed: ", err)
+	}
+
+	if err := ep.Connect(tcpip.FullAddress{NIC: 0, Addr: "", Port: uint16(localPort)}); err != nil {
+		log.Fatal("Conn failed: ", err)
+	}
+
+	// 注意UDP是无连接的，它不需要Listen
+	return ep
+}