initial commit

.gitignore

@@ -0,0 +1,13 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+*.bat
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out

Dockerfile

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+FROM golang:latest
+
+ENV SOURCE_ADDR=127.0.0.1:80
+ENV DESTINATION_ADDR=127.0.0.1:8071
+
+RUN mkdir /app 
+ADD . /app/ 
+WORKDIR /app 
+RUN go build -o main . 
+CMD ["/app/main"]

main.go

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+package main
+
+import (
+	"log"
+	"os"
+)
+
+func main() {
+	p := Server{
+		Addr:   os.Getenv("SOURCE_ADDR"),
+		Target: os.Getenv("DESTINATION_ADDR"),
+	}
+
+	log.Panicln(p.ListenAndServe())
+}

proxy.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"log"
+	"net"
+)
+
+type Server struct {
+	Addr   string
+	Target string
+}
+
+func (s *Server) ListenAndServe() error {
+	listener, err := net.Listen("tcp", s.Addr)
+	if err != nil {
+		return err
+	}
+	return s.serve(listener)
+}
+
+func (s *Server) serve(ln net.Listener) error {
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+		go s.handleConn(conn)
+	}
+}
+
+func (s *Server) handleConn(conn net.Conn) {
+	rconn, err := net.Dial("tcp", s.Target)
+	if err != nil {
+		return
+	}
+
+	var pipe = func(src, dst net.Conn) {
+		defer func() {
+			conn.Close()
+			rconn.Close()
+		}()
+
+		buff := make([]byte, 65535)
+		for {
+			n, err := src.Read(buff)
+			if err != nil {
+				log.Println(err)
+				return
+			}
+			b := buff[:n]
+
+			_, err = dst.Write(b)
+			if err != nil {
+				log.Println(err)
+				return
+			}
+		}
+	}
+
+	go pipe(conn, rconn)
+	go pipe(rconn, conn)
+}