From: Stephen Hemminger <shemminger@linux-foundation.org>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: bridge: faster compare for link local addresses
Date: Mon, 12 Mar 2007 16:20:15 -0700 [thread overview]
Message-ID: <20070312162015.5d22cd68@dxpl.pdx.osdl.net> (raw)
Use logic operations rather than memcmp() to compare destination
address with link local multicast addresses.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
---
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;
}
/*
next reply other threads:[~2007-03-12 23:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-12 23:20 Stephen Hemminger [this message]
2007-03-12 23:26 ` bridge: faster compare for link local addresses David Miller
2007-03-13 0:05 ` Rick Jones
2007-03-13 0:10 ` David Miller
2007-03-13 14:01 ` Andi Kleen
2007-03-13 13:38 ` Eric Dumazet
2007-03-13 19:39 ` David Miller
2007-03-13 20:06 ` Stephen Hemminger
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