[PATCH] BRIDGE: Fix faulty check in br_stp_recalculate_bridge_id()

There is a regression in 2.6.15.
One of the conversions from memcmp to compare_ether_addr is incorrect.
We need to do relative comparison to determine min MAC address to
use in bridge id. This will cause the wrong bridge id to be chosen
which violates 802.1d Spanning Tree Protocol, and may create forwarding
loops.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index ac09b6a2352317cde8ee4a43a2db1a01a3caab71..491f49d72750dc9711c3666d60cb26e698d36622 100644 (file)
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -158,7 +158,7 @@ void br_stp_recalculate_bridge_id(struct net_bridge *br)
 
        list_for_each_entry(p, &br->port_list, list) {
                if (addr == br_mac_zero ||
-                   compare_ether_addr(p->dev->dev_addr, addr) < 0)
+                   memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
                        addr = p->dev->dev_addr;
 
        }