bridge: Support 802.1ad vlan filtering

This enables us to change the vlan protocol for vlan filtering.
We come to be able to filter frames on the basis of 802.1ad vlan tags
through a bridge.

This also changes br->group_addr if it has not been set by user.
This is needed for an 802.1ad bridge.
(See IEEE 802.1Q-2011 8.13.5.)

Furthermore, this sets br->group_fwd_mask_required so that an 802.1ad
bridge can forward the Nearest Customer Bridge group addresses except
for br->group_addr, which should be passed to higher layer.

To change the vlan protocol, write a protocol in sysfs:
# echo 0x88a8 > /sys/class/net/br0/bridge/vlan_protocol

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 0 deletions

diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 8dac6555..c9e2572 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -312,10 +312,19 @@ static ssize_t group_addr_store(struct device *d,
 	    new_addr[5] == 3)		/* 802.1X PAE address */
 		return -EINVAL;
 
+	if (!rtnl_trylock())
+		return restart_syscall();
+
 	spin_lock_bh(&br->lock);
 	for (i = 0; i < 6; i++)
 		br->group_addr[i] = new_addr[i];
 	spin_unlock_bh(&br->lock);
+
+	br->group_addr_set = true;
+	br_recalculate_fwd_mask(br);
+
+	rtnl_unlock();
+
 	return len;
 }
 
@@ -700,6 +709,22 @@ static ssize_t vlan_filtering_store(struct device *d,
 	return store_bridge_parm(d, buf, len, br_vlan_filter_toggle);
 }
 static DEVICE_ATTR_RW(vlan_filtering);
+
+static ssize_t vlan_protocol_show(struct device *d,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	struct net_bridge *br = to_bridge(d);
+	return sprintf(buf, "%#06x\n", ntohs(br->vlan_proto));
+}
+
+static ssize_t vlan_protocol_store(struct device *d,
+				   struct device_attribute *attr,
+				   const char *buf, size_t len)
+{
+	return store_bridge_parm(d, buf, len, br_vlan_set_proto);
+}
+static DEVICE_ATTR_RW(vlan_protocol);
 #endif
 
 static struct attribute *bridge_attrs[] = {
@@ -745,6 +770,7 @@ static struct attribute *bridge_attrs[] = {
 #endif
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING
 	&dev_attr_vlan_filtering.attr,
+	&dev_attr_vlan_protocol.attr,
 #endif
 	NULL
 };