From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: bridge: faster compare for link local addresses Date: Mon, 12 Mar 2007 16:20:15 -0700 Message-ID: <20070312162015.5d22cd68@dxpl.pdx.osdl.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from smtp.osdl.org ([65.172.181.24]:49606 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752319AbXCLXVB (ORCPT ); Mon, 12 Mar 2007 19:21:01 -0400 Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Use logic operations rather than memcmp() to compare destination address with link local multicast addresses. Signed-off-by: Stephen Hemminger --- net/bridge/br_input.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- netem-dev.orig/net/bridge/br_input.c +++ netem-dev/net/bridge/br_input.c @@ -112,7 +112,11 @@ static int br_handle_local_finish(struct */ static inline int is_link_local(const unsigned char *dest) { - return memcmp(dest, br_group_address, 5) == 0 && (dest[5] & 0xf0) == 0; + const u16 *a = (const u16 *) dest; + static const u16 *const b = (const u16 *const ) br_group_address; + static const u16 m = __constant_cpu_to_be16(0xfff0); + + return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; } /*