分别添加了tcp隧道代理和socks代理的两个demo

demo/socks/main.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+)
+
+func main() {
+	server, err := net.Listen("tcp", ":1080")
+	if err != nil {
+		fmt.Printf("Listen failed: %v\n", err)
+		return
+	}
+
+	for {
+		client, err := server.Accept()
+		if err != nil {
+			fmt.Printf("Accept failed: %v", err)
+			continue
+		}
+		go process(client)
+	}
+}
+
+func process(client net.Conn) {
+	if err := Socks5Auth(client); err != nil {
+		fmt.Println("auth error:", err)
+		client.Close()
+		return
+	}
+
+	target, err := Socks5Connect(client)
+	if err != nil {
+		fmt.Println("connect error:", err)
+		client.Close()
+		return
+	}
+
+	Socks5Forward(client, target)
+}
+
+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 Socks5Connect(client net.Conn) (net.Conn, error) {
+	buf := make([]byte, 256)
+
+	n, err := io.ReadFull(client, buf[:4])
+	if n != 4 {
+		return nil, errors.New("read header: " + err.Error())
+	}
+
+	ver, cmd, _, atyp := buf[0], buf[1], buf[2], buf[3]
+	if ver != 5 || cmd != 1 {
+		return nil, errors.New("invalid ver/cmd")
+	}
+
+	addr := ""
+	switch atyp {
+	case 1:
+		n, err = io.ReadFull(client, buf[:4])
+		if n != 4 {
+			return nil, 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 nil, errors.New("invalid hostname: " + err.Error())
+		}
+		addrLen := int(buf[0])
+		n, err = io.ReadFull(client, buf[:addrLen])
+		if n != addrLen {
+			return nil, errors.New("invalid hostname: " + err.Error())
+		}
+		addr = string(buf[:addrLen])
+	case 4:
+		return nil, errors.New("IPv6: no supported yet")
+	default:
+		return nil, errors.New("invalid atyp")
+	}
+
+	n, err = io.ReadFull(client, buf[:2])
+	if n != 2 {
+		return nil, errors.New("read port: " + err.Error())
+	}
+	port := binary.BigEndian.Uint16(buf[:2])
+
+	destAddrPort := fmt.Sprintf("%s:%d", addr, port)
+	dest, err := net.Dial("tcp", destAddrPort)
+	if err != nil {
+		return nil, errors.New("dial dst: " + err.Error())
+	}
+
+	n, err = client.Write([]byte{0x05, 0x00, 0x00, 0x01, 0, 0, 0, 0, 0, 0})
+	if err != nil {
+		dest.Close()
+		return nil, errors.New("write rsp: " + err.Error())
+	}
+	return dest, nil
+}
+
+func Socks5Forward(client, target net.Conn) {
+	forward := func(src, dest net.Conn) {
+		defer src.Close()
+		defer dest.Close()
+		io.Copy(src, dest)
+	}
+	go forward(client, target)
+	go forward(target, client)
+}

demo/tcp/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"os"
+)
+
+func main() {
+	host := "0.0.0.0"
+	port := "777"
+	l, err := net.Listen("tcp", fmt.Sprintf("%s:%s", host, port))
+	if err != nil {
+		fmt.Println(err, err.Error())
+		os.Exit(0)
+	}
+
+	for {
+		s_conn, err := l.Accept()
+		if err != nil {
+			continue
+		}
+
+		d_tcpAddr, _ := net.ResolveTCPAddr("tcp4", "117.111.52.24:80")
+		d_conn, err := net.DialTCP("tcp", nil, d_tcpAddr)
+		if err != nil {
+			fmt.Println(err)
+			s_conn.Write([]byte("can't connect 117.111.52.24:80"))
+			s_conn.Close()
+			continue
+		}
+		go io.Copy(s_conn, d_conn)
+		go io.Copy(d_conn, s_conn)
+	}
+}