add server example

examples/server.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"github.com/ginuerzh/gosocks5"
+	"io"
+	"log"
+	"net"
+)
+
+func main() {
+	log.SetFlags(log.Lshortfile | log.LstdFlags)
+
+	server := &gosocks5.Server{
+		Addr:   ":9999",
+		Handle: handle,
+	}
+
+	server.Serve()
+}
+
+func handle(conn net.Conn, method uint8) error {
+	defer conn.Close()
+
+	req, err := gosocks5.ReadRequest(conn)
+	if err != nil {
+		log.Println(err)
+		return err
+	}
+	tconn, err := Connect(req.Addr.String())
+	if err != nil {
+		log.Println(err)
+		return err
+	}
+	defer tconn.Close()
+
+	rep := gosocks5.NewReply(gosocks5.Succeeded, nil)
+	if err := rep.Write(conn); err != nil {
+		return err
+	}
+
+	if err := Transport(conn, tconn); err != nil {
+		log.Println(err)
+	}
+
+	return nil
+}
+
+func Connect(addr string) (net.Conn, error) {
+	taddr, err := net.ResolveTCPAddr("tcp", addr)
+	if err != nil {
+		log.Println(err)
+		return nil, err
+	}
+	return net.DialTCP("tcp", nil, taddr)
+}
+
+func Copy(dst io.Writer, src io.Reader) (written int64, err error) {
+	buf := make([]byte, 32*1024)
+	for {
+		nr, er := src.Read(buf)
+		//log.Println("cp r", nr, er)
+		if nr > 0 {
+			nw, ew := dst.Write(buf[:nr])
+			//log.Println("cp w", nw, ew)
+			if nw > 0 {
+				written += int64(nw)
+			}
+			if ew != nil {
+				err = ew
+				break
+			}
+			/*
+				if nr != nw {
+					err = io.ErrShortWrite
+					break
+				}
+			*/
+		}
+		if er == io.EOF {
+			break
+		}
+		if er != nil {
+			err = er
+			break
+		}
+	}
+	return
+}
+
+func Pipe(src io.Reader, dst io.Writer, c chan<- error) {
+	_, err := Copy(dst, src)
+	c <- err
+}
+
+func Transport(conn, conn2 net.Conn) (err error) {
+	rChan := make(chan error, 1)
+	wChan := make(chan error, 1)
+
+	go Pipe(conn, conn2, wChan)
+	go Pipe(conn2, conn, rChan)
+
+	select {
+	case err = <-wChan:
+		//log.Println("w exit", err)
+	case err = <-rChan:
+		//log.Println("r exit", err)
+	}
+
+	return
+}