Initial commit

internal/domains/deconnector/tunnel.go

@@ -0,0 +1,43 @@
+package deconnector
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+)
+
+func (d *Deconnector) handleTunnel(clientConn net.Conn, host string, upstreamURL *url.URL) {
+	d.app.Logger().WithField("host", host).Info("Handling CONNECT tunnel")
+
+	upstreamConn, err := d.dialer.Dial()
+	if err != nil {
+		d.app.Logger().WithError(err).Error("upstream dial failed")
+		fmt.Fprintf(clientConn, "HTTP/1.1 502 Bad Gateway\r\n\r\n")
+
+		return
+	}
+	defer upstreamConn.Close()
+
+	connectLine := fmt.Sprintf(
+		"CONNECT %s HTTP/1.1\r\nHost: %s\r\n\r\n", host, host,
+	)
+	fmt.Fprint(upstreamConn, connectLine)
+
+	resp, err := http.ReadResponse(bufio.NewReader(upstreamConn), nil)
+	if err != nil || resp.StatusCode > 499 {
+		d.app.Logger().WithError(err).Error("upstream CONNECT failed")
+		fmt.Fprintf(clientConn, "HTTP/1.1 502 Bad Gateway\r\n\r\n")
+
+		return
+	}
+
+	fmt.Fprintf(clientConn, "HTTP/1.1 200 Connection established\r\n\r\n")
+
+	done := make(chan struct{}, 2)
+	go func() { io.Copy(upstreamConn, clientConn); done <- struct{}{} }()
+	go func() { io.Copy(clientConn, upstreamConn); done <- struct{}{} }()
+	<-done
+}