Add a new protocol

Co-authored-by: Gérald Croës <gerald@containo.us>

tcp/proxy.go

@@ -0,0 +1,50 @@
+package tcp
+
+import (
+	"io"
+	"net"
+
+	"github.com/containous/traefik/log"
+)
+
+// Proxy forwards a TCP request to a TCP service
+type Proxy struct {
+	target *net.TCPAddr
+}
+
+// NewProxy creates a new Proxy
+func NewProxy(address string) (*Proxy, error) {
+	tcpAddr, err := net.ResolveTCPAddr("tcp", address)
+	if err != nil {
+		return nil, err
+	}
+	return &Proxy{
+		target: tcpAddr,
+	}, nil
+}
+
+// ServeTCP forwards the connection to a service
+func (p *Proxy) ServeTCP(conn net.Conn) {
+	log.Debugf("Handling connection from %s", conn.RemoteAddr())
+	defer conn.Close()
+	connBackend, err := net.DialTCP("tcp", nil, p.target)
+	if err != nil {
+		log.Errorf("Error while connection to backend: %v", err)
+		return
+	}
+	defer connBackend.Close()
+
+	errChan := make(chan error, 1)
+	go connCopy(conn, connBackend, errChan)
+	go connCopy(connBackend, conn, errChan)
+
+	err = <-errChan
+	if err != nil {
+		log.Errorf("Error during connection: %v", err)
+	}
+}
+
+func connCopy(dst, src net.Conn, errCh chan error) {
+	_, err := io.Copy(dst, src)
+	errCh <- err
+}