尝试整个网络代理 以netstack为代理服务器，想实现网络通信的server调用特殊的api代理，要如何避开内核网络栈呢?

cmd/netstack/main.go

@@ -0,0 +1,215 @@
+package main
+
+import (
+	"encoding/binary"
+	"flag"
+	"io"
+	"log"
+	"net"
+	"netstack/tcpip"
+	"netstack/tcpip/header"
+	"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"
+	"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()) != 2 {
+		log.Fatal("Usage: ", os.Args[0], " <tap-device> <listen-address>")
+	}
+
+	log.SetFlags(log.Lshortfile | log.LstdFlags)
+	tapName := flag.Arg(0)
+	listeAddr := flag.Arg(1)
+
+	log.Printf("tap: %v, listeAddr: %v", tapName, listeAddr)
+
+	// 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)
+	}
+
+	// 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,
+		},
+	})
+
+	conn, _ := net.Listen("tcp", "0.0.0.0:9999")
+	TCPServer(conn, &RCV{s, nil, nil})
+	// 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
+}
+
+type RCV struct {
+	*stack.Stack
+	ep     tcpip.Endpoint
+	rcvBuf []byte
+}
+
+var transportPool = make(map[uint64]tcpip.Endpoint)
+
+func (r *RCV) Handle(conn net.Conn) {
+	var err error
+	r.rcvBuf, err = io.ReadAll(conn)
+	if err != nil && len(r.rcvBuf) < 9 { // proto + ip + port
+		panic(err)
+	}
+
+	switch string(r.rcvBuf[:3]) {
+	case "udp":
+		var wq waiter.Queue
+		// 新建一个udp端
+		ep, err := r.NewEndpoint(udp.ProtocolNumber, header.IPv4ProtocolNumber, &wq)
+		if err != nil {
+			log.Fatal(err)
+		}
+		r.ep = ep
+		r.Bind()
+		r.Close()
+	case "tcp":
+	default:
+		return
+	}
+}
+
+func (r *RCV) Bind() {
+	if len(r.rcvBuf) < 9 { // udp ip port
+		log.Println("Error: too few arg")
+		return
+	}
+	port := binary.BigEndian.Uint16(r.rcvBuf[7:9])
+	addr := tcpip.FullAddress{
+		NIC:  0,
+		Addr: tcpip.Address(r.rcvBuf[3:7]),
+		Port: port,
+	}
+	r.ep.Bind(addr, nil)
+}
+
+func (r *RCV) Close() {
+	r.ep.Close()
+}

cmd/netstack/tcp_server.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"runtime"
+	"strings"
+)
+
+type TCPHandler interface {
+	Handle(net.Conn)
+}
+
+func TCPServer(listener net.Listener, handler TCPHandler) error {
+	log.Printf("netstack 网络解析地址: %s", listener.Addr())
+
+	for {
+		clientConn, err := listener.Accept()
+		if err != nil {
+			if nerr, ok := err.(net.Error); ok && nerr.Temporary() {
+				log.Printf("temporary Accept() failure - %s", err)
+				runtime.Gosched()
+				continue
+			}
+			// theres no direct way to detect this error because it is not exposed
+			if !strings.Contains(err.Error(), "use of closed network connection") {
+				return fmt.Errorf("listener.Accept() error - %s", err)
+			}
+			break
+		}
+		go handler.Handle(clientConn)
+	}
+
+	log.Printf("TCP: closing %s", listener.Addr())
+
+	return nil
+}

cmd/udp/main.go

@@ -5,120 +5,32 @@ import (
 	"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 {
+	if len(flag.Args()) != 2 {
-		log.Fatal("Usage: ", os.Args[0], " <tap-device> <listen-address> port")
+		log.Fatal("Usage: ", os.Args[0], "<listen-address> port")
 	}
 
 	log.SetFlags(log.Lshortfile | log.LstdFlags)
-	tapName := flag.Arg(0)
+	listeAddr := flag.Arg(0)
-	listeAddr := flag.Arg(1)
+	portName := flag.Arg(1)
-	portName := flag.Arg(2)
 
-	log.Printf("tap: %v, listeAddr: %v, portName: %v", tapName, listeAddr, portName)
+	Socket(listeAddr + ":" + portName)
+}
 
-	// Parse the mac address.
+func Socket(addr string) {
-	maddr, err := net.ParseMAC(*mac)
+	conn, err := net.Dial("tcp", addr)
 	if err != nil {
-		log.Fatalf("Bad MAC address: %v", *mac)
+		panic(err)
 	}
-
+	conn.Write([]byte("udp\xc0\xa8\x01\x01\x27\x0f")) // bind udp 192.168.1.1 9999
-	parsedAddr := net.ParseIP(listeAddr)
+	conn.Close()
-
-	// 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 {

tcpip/stack/stack.go

@@ -76,6 +76,7 @@ type Options struct {
 	Stats tcpip.Stats
 }
 
+// New 新建一个网络协议栈
 func New(network []string, transport []string, opts Options) *Stack {
 	clock := opts.Clock
 	if clock == nil {
@@ -115,7 +116,9 @@ func New(network []string, transport []string, opts Options) *Stack {
 			proto: transProto,
 		}
 	}
-	// TODO 添加传输层分流器
+	// 添加传输层分流器
+	s.demux = newTransportDemuxer(s)
+
 	return s
 }
 

tcpip/stack/transport_demuxer.go

@@ -21,3 +21,8 @@ type transportEndpoints struct {
 type transportDemuxer struct {
 	protocol map[protocolIDs]*transportEndpoints
 }
+
+// 新建一个分流器
+func newTransportDemuxer(stacl *Stack) *transportDemuxer {
+	return nil
+}