package tcp import ( "io" "net" "time" "github.com/containous/traefik/v2/pkg/log" ) // Proxy forwards a TCP request to a TCP service type Proxy struct { target *net.TCPAddr terminationDelay time.Duration } // NewProxy creates a new Proxy func NewProxy(address string, terminationDelay time.Duration) (*Proxy, error) { tcpAddr, err := net.ResolveTCPAddr("tcp", address) if err != nil { return nil, err } return &Proxy{target: tcpAddr, terminationDelay: terminationDelay}, nil } // ServeTCP forwards the connection to a service func (p *Proxy) ServeTCP(conn WriteCloser) { log.Debugf("Handling connection from %s", conn.RemoteAddr()) // needed because of e.g. server.trackedConnection defer conn.Close() connBackend, err := net.DialTCP("tcp", nil, p.target) if err != nil { log.Errorf("Error while connection to backend: %v", err) return } // maybe not needed, but just in case defer connBackend.Close() errChan := make(chan error) go p.connCopy(conn, connBackend, errChan) go p.connCopy(connBackend, conn, errChan) err = <-errChan if err != nil { log.WithoutContext().Errorf("Error during connection: %v", err) } <-errChan } func (p Proxy) connCopy(dst, src WriteCloser, errCh chan error) { _, err := io.Copy(dst, src) errCh <- err errClose := dst.CloseWrite() if errClose != nil { log.WithoutContext().Debugf("Error while terminating connection: %v", errClose) return } if p.terminationDelay >= 0 { err := dst.SetReadDeadline(time.Now().Add(p.terminationDelay)) if err != nil { log.WithoutContext().Debugf("Error while setting deadline: %v", err) } } }