From 6070aa9e80f178cbed2f0f836b5d1929569536f7 Mon Sep 17 00:00:00 2001
From: Hatter Jiang <jht5945@gmail.com>
Date: Mon, 27 Nov 2023 21:49:48 +0800
Subject: [PATCH] feat: add tcp2tls_client.go, tls2tcp_server.go

---
 README.md         |  11 ++++
 tcp2tls_client.go | 143 ++++++++++++++++++++++++++++++++++++++++++++++
 tls2tcp_server.go | 105 ++++++++++++++++++++++++++++++++++
 3 files changed, 259 insertions(+)
 create mode 100644 tcp2tls_client.go
 create mode 100644 tls2tcp_server.go

diff --git a/README.md b/README.md
index 44be2e7..b4247ab 100644
--- a/README.md
+++ b/README.md
@@ -15,3 +15,14 @@ Config sample:
 }
 
 ```
+
+
+----
+
+Codes:
+* tcp2tls_client.go
+* tls2tcp_server.go
+
+Copied from: https://gist.github.com/cs8425/a742349a55596f1b251a
+
+
diff --git a/tcp2tls_client.go b/tcp2tls_client.go
new file mode 100644
index 0000000..4ff8248
--- /dev/null
+++ b/tcp2tls_client.go
@@ -0,0 +1,143 @@
+package main
+
+import (
+	"log"
+	"crypto/tls"
+	"net"
+)
+
+const localAddr string = "127.0.0.1:9999"
+const remoteAddr string = "127.0.0.1:25500"
+const MaxConn int16 = 3
+
+func proxyConn(conn net.Conn) {
+	defer conn.Close()
+
+	rAddr, err := net.ResolveTCPAddr("tcp", remoteAddr)
+	if err != nil {
+		log.Print(err)
+	}
+
+	conf := &tls.Config{
+		InsecureSkipVerify: true,
+	}
+
+	//rConn, err := net.DialTCP("tcp", nil, rAddr)
+	rConn, err := tls.Dial("tcp", rAddr.String(), conf)
+	if err != nil {
+		log.Print(err)
+		return
+	}
+	defer rConn.Close()
+
+//	log.Printf("remoteAddr connected: %v\n", rAddr.String())
+
+	Pipe(conn, rConn)
+//	log.Printf("proxyConn end: %v -> %v\n", conn.RemoteAddr(), rConn.RemoteAddr())
+}
+
+func chanFromConn(conn net.Conn) chan []byte {
+	c := make(chan []byte)
+
+	go func() {
+		b := make([]byte, 1024)
+
+		for {
+			n, err := conn.Read(b)
+			if n > 0 {
+				res := make([]byte, n)
+				// Copy the buffer so it doesn't get changed while read by the recipient.
+				copy(res, b[:n])
+				c <- res
+			}
+			if err != nil {
+				c <- nil
+				break
+			}
+		}
+	}()
+
+	return c
+}
+
+func Pipe(conn1 net.Conn, conn2 net.Conn) {
+	chan1 := chanFromConn(conn1)
+	chan2 := chanFromConn(conn2)
+
+	for {
+		select {
+		case b1 := <-chan1:
+			if b1 == nil {
+				return
+			} else {
+				conn2.Write(b1)
+			}
+		case b2 := <-chan2:
+			if b2 == nil {
+				return
+			} else {
+				conn1.Write(b2)
+			}
+		}
+	}
+}
+
+func main() {
+	log.SetFlags(log.Lshortfile)
+
+	log.Printf("Listening: %v -> %v\n\n", localAddr, remoteAddr)
+
+	addr, err := net.ResolveTCPAddr("tcp", localAddr)
+	if err != nil {
+		panic(err)
+	}
+
+	listener, err := net.ListenTCP("tcp", addr)
+	if err != nil {
+		panic(err)
+	}
+
+	var i int16 = 0;
+	count := make(chan int16, 1)
+	for {
+		log.Printf("wait accepted...\n")
+		conn, err := listener.AcceptTCP()
+		if err != nil {
+			log.Print(err)
+		}
+		//go proxyConn(conn);
+		
+		//log.Printf("accepted: %v\n", conn.RemoteAddr())
+		select {
+			case t := <- count:
+				i += t 
+//				print("received ", i, "\n")
+
+			default:
+				
+		}
+		if i < MaxConn {
+			i++
+			log.Printf("[%v/%v]accepted: %v\n", i, MaxConn, conn.RemoteAddr())
+
+			// Create a new goroutine which will call the connection handler and  then free up the space.
+			go func(connection net.Conn) {
+				proxyConn(connection)
+//				log.Printf("[%v/%v]Closed connection from %s\r\n", i, MaxConn, connection.RemoteAddr())
+				log.Printf("Closed connection from %s\r\n", connection.RemoteAddr())
+				select {
+					case t := <- count:
+						count <- t-1 
+
+					default:
+						count <- -1
+				}
+			}(conn)
+		}else{
+			conn.Close()
+//			log.Printf("closed: %v\n", i)
+		}
+	}
+
+}
+
diff --git a/tls2tcp_server.go b/tls2tcp_server.go
new file mode 100644
index 0000000..4897b5a
--- /dev/null
+++ b/tls2tcp_server.go
@@ -0,0 +1,105 @@
+package main
+
+import (
+	"log"
+	"crypto/tls"
+	"net"
+)
+
+const localAddr string = ":25500"
+const remoteAddr string = "127.0.0.1:25501"
+const MaxConn int16 = 3
+
+func main() {
+	log.SetFlags(log.Lshortfile)
+
+	cer, err := tls.LoadX509KeyPair("server.pem", "server.key")
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	config := &tls.Config{Certificates: []tls.Certificate{cer}}
+	ln, err := tls.Listen("tcp", localAddr, config) 
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	defer ln.Close()
+
+	log.Printf("Listening: %v -> %v\n\n", localAddr, remoteAddr)
+
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+		go proxyConn(conn)
+	}
+}
+
+func proxyConn(conn net.Conn) {
+	defer conn.Close()
+
+	rAddr, err := net.ResolveTCPAddr("tcp", remoteAddr)
+	if err != nil {
+		log.Print(err)
+	}
+
+	rConn, err := net.DialTCP("tcp", nil, rAddr)
+	if err != nil {
+		log.Print(err)
+	}
+	defer rConn.Close()
+
+	Pipe(conn, rConn)
+
+	log.Printf("handleConnection end: %s\n", conn.RemoteAddr())
+}
+
+func chanFromConn(conn net.Conn) chan []byte {
+	c := make(chan []byte)
+
+	go func() {
+		b := make([]byte, 1024)
+
+		for {
+			n, err := conn.Read(b)
+			if n > 0 {
+				res := make([]byte, n)
+				// Copy the buffer so it doesn't get changed while read by the recipient.
+				copy(res, b[:n])
+				c <- res
+			}
+			if err != nil {
+				c <- nil
+				break
+			}
+		}
+	}()
+
+	return c
+}
+
+func Pipe(conn1 net.Conn, conn2 net.Conn) {
+	chan1 := chanFromConn(conn1)
+	chan2 := chanFromConn(conn2)
+
+	for {
+		select {
+		case b1 := <-chan1:
+			if b1 == nil {
+				return
+			} else {
+				conn2.Write(b1)
+			}
+		case b2 := <-chan2:
+			if b2 == nil {
+				return
+			} else {
+				conn1.Write(b2)
+			}
+		}
+	}
+}