resubmit bridge: fix message_age_timer calculation
Chris Healy [Thu, 12 Sep 2013 04:37:47 +0000 (21:37 -0700)]
[ Upstream commit 9a0620133ccce9dd35c00a96405c8d80938c2cc0 ]

This changes the message_age_timer calculation to use the BPDU's max age as
opposed to the local bridge's max age.  This is in accordance with section
8.6.2.3.2 Step 2 of the 802.1D-1998 sprecification.

With the current implementation, when running with very large bridge
diameters, convergance will not always occur even if a root bridge is
configured to have a longer max age.

Tested successfully on bridge diameters of ~200.

Signed-off-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/bridge/br_stp.c

index 1c0a50f..f1887ba 100644 (file)
@@ -209,7 +209,7 @@ static void br_record_config_information(struct net_bridge_port *p,
        p->designated_age = jiffies - bpdu->message_age;
 
        mod_timer(&p->message_age_timer, jiffies
-                 + (p->br->max_age - bpdu->message_age));
+                 + (bpdu->max_age - bpdu->message_age));
 }
 
 /* called under bridge lock */