commit bba0bb6613c703b8aa840bd67e58b8618f7a3db0
Author: Ambrose Chua <ambrose@chua.family>
Date:   Thu Mar 1 20:24:15 2018 +0800

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..50a6d96
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+.DS_Store
+forward
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d5efbe8
--- /dev/null
+++ b/README.md
@@ -0,0 +1,16 @@
+
+# forward
+
+A simple TCP proxy. 
+
+## Usage 
+
+```
+$ ./forward -help
+Usage of ./forward:
+  -connect string
+    	forward to ip and port (default ":8080")
+  -listen string
+    	listen on ip and port (default ":8081")
+```
+
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..3d8e2cc
--- /dev/null
+++ b/main.go
@@ -0,0 +1,68 @@
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"net"
+)
+
+var listen string
+var connect string
+
+func main() {
+	flag.StringVar(&listen, "listen", ":8000", "listen on ip and port")
+	flag.StringVar(&connect, "connect", "", "forward to ip and port")
+	flag.Parse()
+
+	// check and parse address
+	conn, err := net.ResolveTCPAddr("tcp", connect)
+	if err != nil {
+		flag.PrintDefaults()
+		log.Fatal(err)
+	}
+
+	// listen on address
+	ln, err := net.Listen("tcp", listen)
+	if err != nil {
+		flag.PrintDefaults()
+		log.Fatal(err)
+	}
+
+	log.Printf("listening on %v", ln.Addr())
+	log.Printf("will connect to %v", conn)
+
+	for i := 0; ; i++ {
+		// accept new connection
+		c, err := ln.Accept()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		log.Printf("connection %v from %v", i, c.RemoteAddr())
+
+		cn, err := net.DialTCP("tcp", nil, conn)
+		if err != nil {
+			c.Close()
+			log.Print(err)
+			continue
+		}
+
+		go pipe(c, cn, i)
+		go pipe(cn, c, i)
+	}
+}
+
+func pipe(w io.WriteCloser, r io.ReadCloser, count int) {
+	n, err := io.Copy(w, r)
+
+	r.Close()
+	w.Close()
+
+	log.Printf("connection %v closed, %v bytes", count, n)
+
+	opError, ok := err.(*net.OpError)
+	if err != nil && (!ok || opError.Op != "readfrom") {
+		log.Printf("warning! %v", err)
+	}
+}