GnuTLS: Implement tls_get_cipher()

Provide OpenSSL-style name for the negotiated cipher suite.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/crypto/tls_gnutls.c

@@ -1538,8 +1538,35 @@ int tls_get_version(void *ssl_ctx, struct tls_connection *conn,
 int tls_get_cipher(void *ssl_ctx, struct tls_connection *conn,
 		   char *buf, size_t buflen)
 {
-	/* TODO */
-	buf[0] = '\0';
+	gnutls_cipher_algorithm_t cipher;
+	gnutls_kx_algorithm_t kx;
+	gnutls_mac_algorithm_t mac;
+	const char *kx_str, *cipher_str, *mac_str;
+	int res;
+
+	cipher = gnutls_cipher_get(conn->session);
+	cipher_str = gnutls_cipher_get_name(cipher);
+	if (!cipher_str)
+		cipher_str = "";
+
+	kx = gnutls_kx_get(conn->session);
+	kx_str = gnutls_kx_get_name(kx);
+	if (!kx_str)
+		kx_str = "";
+
+	mac = gnutls_mac_get(conn->session);
+	mac_str = gnutls_mac_get_name(mac);
+	if (!mac_str)
+		mac_str = "";
+
+	if (kx == GNUTLS_KX_RSA)
+		res = os_snprintf(buf, buflen, "%s-%s", cipher_str, mac_str);
+	else
+		res = os_snprintf(buf, buflen, "%s-%s-%s",
+				  kx_str, cipher_str, mac_str);
+	if (os_snprintf_error(buflen, res))
+		return -1;
+
 	return 0;
 }