新增socks和tcp代理的demo

demo/client/socks/main.go

@@ -0,0 +1,214 @@
+package main
+
+import (
+	"encoding/binary"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"os"
+	"strconv"
+	"sync"
+	"time"
+)
+
+type Addr []byte
+
+const (
+	AtypIPv4       = 1
+	AtypDomainName = 3
+	AtypIPv6       = 4
+)
+
+var local = flag.String("local", "127.0.0.1:1080", "please enter local proxy ip")
+var server = flag.String("server", "192.168.0.104:8805", "please enter tcp tunnel server ip")
+
+func main() {
+	flag.Parse()
+	l, err := net.Listen("tcp", *local)
+	if err != nil {
+		fmt.Printf("Listen failed: %v\n", err)
+		return
+	}
+
+	for {
+		c, err := l.Accept()
+		if err != nil {
+			fmt.Printf("Accept failed: %v", err)
+			continue
+		}
+
+		go func() {
+
+			if err := socks5Auth(c); err != nil {
+				fmt.Println("auth error:", err)
+				c.Close()
+				return
+			}
+
+			targetIP, err := getTargetIP(c)
+			if err != nil {
+				log.Fatal("don't get target ip ,err is " + err.Error())
+				return
+			}
+
+			tgt := ParseAddr(targetIP)
+
+			rc, err := net.Dial("tcp", *server)
+			if err != nil {
+				log.Fatal("can't connect " + *server)
+				c.Write([]byte("can't connect " + *server))
+				c.Close()
+
+			}
+
+			if _, err = rc.Write(tgt); err != nil {
+				log.Fatal("failed to send target address: ", err.Error()+"\n")
+				return
+			}
+
+			log.Println("proxy " + c.RemoteAddr().String() + "<->" + *server + "<->" + targetIP)
+			if err = relay(rc, c); err != nil {
+				log.Fatal(err.Error() + "\n")
+			}
+		}()
+	}
+}
+
+func socks5Auth(client net.Conn) (err error) {
+	buf := make([]byte, 256)
+
+	// 读取 VER 和 NMETHODS
+	n, err := io.ReadFull(client, buf[:2])
+	if n != 2 {
+		return errors.New("reading header: " + err.Error())
+	}
+
+	ver, nMethods := int(buf[0]), int(buf[1])
+	if ver != 5 {
+		return errors.New("invalid version")
+	}
+
+	// 读取 METHODS 列表
+	n, err = io.ReadFull(client, buf[:nMethods])
+	if n != nMethods {
+		return errors.New("reading methods: " + err.Error())
+	}
+
+	n, err = client.Write([]byte{0x05, 0x00})
+	if n != 2 || err != nil {
+		return errors.New("write rsp err: " + err.Error())
+	}
+
+	return nil
+}
+
+func getTargetIP(client net.Conn) (string, error) {
+	buf := make([]byte, 256)
+
+	n, err := io.ReadFull(client, buf[:4])
+	if n != 4 {
+		return "", errors.New("read header: " + err.Error())
+	}
+
+	ver, cmd, _, atyp := buf[0], buf[1], buf[2], buf[3]
+	if ver != 5 || cmd != 1 {
+		return "", errors.New("invalid ver/cmd")
+	}
+
+	addr := ""
+	switch atyp {
+	case 1:
+		n, err = io.ReadFull(client, buf[:4])
+		if n != 4 {
+			return "", errors.New("invalid IPv4: " + err.Error())
+		}
+		addr = fmt.Sprintf("%d.%d.%d.%d", buf[0], buf[1], buf[2], buf[3])
+	case 3:
+		n, err = io.ReadFull(client, buf[:1])
+		if n != 1 {
+			return "", errors.New("invalid hostname: " + err.Error())
+		}
+		addrLen := int(buf[0])
+		n, err = io.ReadFull(client, buf[:addrLen])
+		if n != addrLen {
+			return "", errors.New("invalid hostname: " + err.Error())
+		}
+		addr = string(buf[:addrLen])
+	case 4:
+		return "", errors.New("IPv6: no supported yet")
+	default:
+		return "", errors.New("invalid atyp")
+	}
+
+	n, err = io.ReadFull(client, buf[:2])
+	if n != 2 {
+		return "", errors.New("read port: " + err.Error())
+	}
+	port := binary.BigEndian.Uint16(buf[:2])
+
+	destAddrPort := fmt.Sprintf("%s:%d", addr, port)
+
+	return destAddrPort, nil
+}
+
+// 将string类型的IP地址转换成[]byte类型
+func ParseAddr(s string) Addr {
+	var addr Addr
+	host, port, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil
+	}
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			addr = make([]byte, 1+net.IPv4len+2)
+			addr[0] = AtypIPv4
+			copy(addr[1:], ip4)
+		} else {
+			addr = make([]byte, 1+net.IPv6len+2)
+			addr[0] = AtypIPv6
+			copy(addr[1:], ip)
+		}
+	} else {
+		if len(host) > 255 {
+			return nil
+		}
+		addr = make([]byte, 1+1+len(host)+2)
+		addr[0] = AtypDomainName
+		addr[1] = byte(len(host))
+		copy(addr[2:], host)
+	}
+
+	portnum, err := strconv.ParseUint(port, 10, 16)
+	if err != nil {
+		return nil
+	}
+
+	addr[len(addr)-2], addr[len(addr)-1] = byte(portnum>>8), byte(portnum)
+
+	return addr
+}
+
+func relay(left, right net.Conn) error {
+	var err, err1 error
+	var wg sync.WaitGroup
+	var wait = 5 * time.Second
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		_, err1 = io.Copy(right, left)
+		right.SetReadDeadline(time.Now().Add(wait)) // unblock read on right
+	}()
+	_, err = io.Copy(left, right)
+	left.SetReadDeadline(time.Now().Add(wait)) // unblock read on left
+	wg.Wait()
+	if err1 != nil && !errors.Is(err1, os.ErrDeadlineExceeded) { // requires Go 1.15+
+		return err1
+	}
+	if err != nil && !errors.Is(err, os.ErrDeadlineExceeded) {
+		return err
+	}
+	return nil
+}

demo/client/tcp/main.go

@@ -0,0 +1,131 @@
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"os"
+	"strconv"
+	"sync"
+	"time"
+)
+
+type Addr []byte
+
+const (
+	AtypIPv4       = 1
+	AtypDomainName = 3
+	AtypIPv6       = 4
+)
+
+var local = flag.String("local", "127.0.0.1:1080", "please enter local proxy ip")
+var target = flag.String("target", "192.168.1.105:8806", "please enter target server ip")
+var server = flag.String("server", "192.168.0.104:8805", "please enter tcp tunnel server ip")
+
+func main() {
+	flag.Parse()
+	tgt := ParseAddr(*target)
+	l, err := net.Listen("tcp", *local)
+	if err != nil {
+		log.Fatalf("failed to listen on %s: %v", *local, err)
+		return
+	}
+
+	log.Println("listening TCP on ", *local)
+	if err != nil {
+		fmt.Println(err, err.Error())
+		os.Exit(0)
+	}
+
+	for {
+		c, err := l.Accept()
+		if err != nil {
+			continue
+		}
+
+		go func() {
+
+			rc, err := net.Dial("tcp", *server)
+			if err != nil {
+				log.Fatal("can't connect " + *server)
+				c.Write([]byte("can't connect " + *server))
+				c.Close()
+
+			}
+
+			if _, err = rc.Write(tgt); err != nil {
+				log.Fatal("failed to send target address: ", err.Error()+"\n")
+				return
+			}
+
+			log.Println("proxy " + c.RemoteAddr().String() + "<->" + *server + "<->" + *target)
+			if err = relay(rc, c); err != nil {
+				log.Fatal(err.Error() + "\n")
+			}
+		}()
+
+	}
+}
+
+// 数据流的转发
+func relay(left, right net.Conn) error {
+	var err, err1 error
+	var wg sync.WaitGroup
+	var wait = 5 * time.Second
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		_, err1 = io.Copy(right, left)
+		right.SetReadDeadline(time.Now().Add(wait)) // unblock read on right
+	}()
+	_, err = io.Copy(left, right)
+	left.SetReadDeadline(time.Now().Add(wait)) // unblock read on left
+	wg.Wait()
+	if err1 != nil && !errors.Is(err1, os.ErrDeadlineExceeded) { // requires Go 1.15+
+		return err1
+	}
+	if err != nil && !errors.Is(err, os.ErrDeadlineExceeded) {
+		return err
+	}
+	return nil
+}
+
+// 将string类型的IP地址转换成[]byte类型
+func ParseAddr(s string) Addr {
+	var addr Addr
+	host, port, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil
+	}
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			addr = make([]byte, 1+net.IPv4len+2)
+			addr[0] = AtypIPv4
+			copy(addr[1:], ip4)
+		} else {
+			addr = make([]byte, 1+net.IPv6len+2)
+			addr[0] = AtypIPv6
+			copy(addr[1:], ip)
+		}
+	} else {
+		if len(host) > 255 {
+			return nil
+		}
+		addr = make([]byte, 1+1+len(host)+2)
+		addr[0] = AtypDomainName
+		addr[1] = byte(len(host))
+		copy(addr[2:], host)
+	}
+
+	portnum, err := strconv.ParseUint(port, 10, 16)
+	if err != nil {
+		return nil
+	}
+
+	addr[len(addr)-2], addr[len(addr)-1] = byte(portnum>>8), byte(portnum)
+
+	return addr
+}