if len(v) == 0 {
		return false
	}
	for i := 0; i < len(v); i++ {
		if !isTokenTable[v[i]] {
			return false
		}
	}
	return true
}

// ValidHostHeader reports whether h is a valid host header.
func ValidHostHeader(h string) bool {
	// The latest spec is actually this:
	//
	// http://tools.ietf.org/html/rfc7230#section-5.4
	//     Host = uri-host [ ":" port ]
	//
	// Where uri-host is:

	// header or request smuggling via the Host field.
	// The server can (and will, if it's a net/http server) reject
	// the request if it doesn't consider the host valid.
	if !httpguts.ValidHostHeader(host) {
		// Historically, we would truncate the Host header after '/' or ' '.
		// Some users have relied on this truncation to convert a network
		// address such as Unix domain socket path into a valid, ignored

	if req.ProtoAtLeast(1, 1) && (!haveHost || len(hosts) == 0) && !isH2Upgrade && req.Method != "CONNECT" {
		return nil, badRequestError("missing required Host header")
	}
	if len(hosts) == 1 && !httpguts.ValidHostHeader(hosts[0]) {
		return nil, badRequestError("malformed Host header")
	}
	for k, vv := range req.Header {
		if !httpguts.ValidHeaderFieldName(k) {
			return nil, badRequestError("invalid header name")
		}

	}

	host := req.Host
	if host == "" {
		host = req.URL.Host
	}
	host, err := httpguts.PunycodeHostPort(host)
	if err != nil {
		return nil, err
	}
	if !httpguts.ValidHostHeader(host) {
		return nil, errors.New("http2: invalid Host header")
	}

	var path string
	if req.Method != "CONNECT" {
		path = req.URL.RequestURI()
		if !http2validPseudoPath(path) {