From 34d8acd8aabb6e070b6fb718909db80458ef32ec Mon Sep 17 00:00:00 2001 From: Vivien Didelot Date: Sat, 10 Dec 2016 13:44:29 -0500 Subject: [PATCH] net: bridge: shorten ageing time on topology change 802.1D [1] specifies that the bridges must use a short value to age out dynamic entries in the Filtering Database for a period, once a topology change has been communicated by the root bridge. Add a bridge_ageing_time member in the net_bridge structure to store the bridge ageing time value configured by the user (ioctl/netlink/sysfs). If we are using in-kernel STP, shorten the ageing time value to twice the forward delay used by the topology when the topology change flag is set. When the flag is cleared, restore the configured ageing time. [1] "8.3.5 Notifying topology changes ", http://profesores.elo.utfsm.cl/~agv/elo309/doc/802.1D-1998.pdf Signed-off-by: Vivien Didelot Signed-off-by: David S. Miller --- net/bridge/br_device.c | 2 +- net/bridge/br_private.h | 3 ++- net/bridge/br_stp.c | 27 +++++++++++++++++++++++++++ 3 files changed, 30 insertions(+), 2 deletions(-) diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c index c08e02b67818..bca5ead3e973 100644 --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -409,7 +409,7 @@ void br_dev_setup(struct net_device *dev) br->bridge_max_age = br->max_age = 20 * HZ; br->bridge_hello_time = br->hello_time = 2 * HZ; br->bridge_forward_delay = br->forward_delay = 15 * HZ; - br->ageing_time = BR_DEFAULT_AGEING_TIME; + br->bridge_ageing_time = br->ageing_time = BR_DEFAULT_AGEING_TIME; dev->max_mtu = ETH_MAX_MTU; br_netfilter_rtable_init(br); diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index e2cd6d12a273..8ce621e8345c 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -300,10 +300,11 @@ struct net_bridge unsigned long max_age; unsigned long hello_time; unsigned long forward_delay; - unsigned long bridge_max_age; unsigned long ageing_time; + unsigned long bridge_max_age; unsigned long bridge_hello_time; unsigned long bridge_forward_delay; + unsigned long bridge_ageing_time; u8 group_addr[ETH_ALEN]; bool group_addr_set; diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index 8d7b4c7a1d54..71fd1a4e63cc 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -597,7 +597,11 @@ int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time) if (err) return err; + spin_lock_bh(&br->lock); + br->bridge_ageing_time = t; br->ageing_time = t; + spin_unlock_bh(&br->lock); + mod_timer(&br->gc_timer, jiffies); return 0; @@ -606,6 +610,29 @@ int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time) /* called under bridge lock */ void __br_set_topology_change(struct net_bridge *br, unsigned char val) { + unsigned long t; + int err; + + if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) { + /* On topology change, set the bridge ageing time to twice the + * forward delay. Otherwise, restore its default ageing time. + */ + + if (val) { + t = 2 * br->forward_delay; + br_debug(br, "decreasing ageing time to %lu\n", t); + } else { + t = br->bridge_ageing_time; + br_debug(br, "restoring ageing time to %lu\n", t); + } + + err = __set_ageing_time(br->dev, t); + if (err) + br_warn(br, "error offloading ageing time\n"); + else + br->ageing_time = t; + } + br->topology_change = val; }