// whether they client has sent exactly one (non-CA) leaf certificate.
	peerCertificates := make([]*x509.Certificate, 0, len(r.TLS.PeerCertificates))
	for _, cert := range r.TLS.PeerCertificates {
		if cert.IsCA {
			continue
		}
		peerCertificates = append(peerCertificates, cert)
	}
	r.TLS.PeerCertificates = peerCertificates

	// Now, we have to check that the client has provided exactly one leaf

		if ip := net.ParseIP(h); ip != nil {
			template.IPAddresses = append(template.IPAddresses, ip)
		} else {
			template.DNSNames = append(template.DNSNames, h)
		}
	}

	template.IsCA = true
	template.KeyUsage |= x509.KeyUsageCertSign

	derBytes, err := x509.CreateCertificate(crand.Reader, &template, &template, publicKey(priv), priv)
	if err != nil {