Subject: Re: [PATCH 6/7] bridge: Manage promisc mode when vlans are configured on top of a bridge

From: Vlad Yasevich <[email-masked]>
Date: Wed, 26 Feb 2014 11:05:40 -0500

On 02/26/2014 11:00 AM, Michael S. Tsirkin wrote:
> On Wed, Feb 26, 2014 at 10:18:24AM -0500, Vlad Yasevich wrote:
>> If the user configures vlan interfaces on top of the bridge and the bridge
>> doesn't have vlan filtering enabled, we have to place all the ports in
>> promsic mode so that we can correctly receive tagged frames.
>> When vlan filtering is enabled, the vlan configuration will be provided
>> via filtering interface.
>> When the vlan filtering is toggled, we also have mange promiscuity.
> 
> have to manage?
> 
>>
>> Signed-off-by: Vlad Yasevich <[email-masked]>
> 
> 
> I wonder if it matters that we scan all ports
> on vlan add/del now.
> 
> If yes, we could optimize some cases by using
> a counter of promisc ports.

Or a bridge flag.  I'll see if can add that to save
repeated list walks without doing any useful work.

Thanks
-vlad

> 
> 
>> ---
>>  net/bridge/br_device.c  | 14 ++++++++++++++
>>  net/bridge/br_if.c      | 17 +++++++++++++----
>>  net/bridge/br_private.h |  9 +++++++++
>>  net/bridge/br_vlan.c    |  1 +
>>  4 files changed, 37 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
>> index 0af9d6c..967abb3 100644
>> --- a/net/bridge/br_device.c
>> +++ b/net/bridge/br_device.c
>> @@ -297,6 +297,18 @@ void br_netpoll_disable(struct net_bridge_port *p)
>>  
>>  #endif
>>  
>> +static int br_dev_rx_add_vid(struct net_device *br_dev, __be16 proto, u16 vid)
>> +{
>> +	br_manage_promisc(netdev_priv(br_dev));
>> +	return 0;
>> +}
>> +
>> +static int br_dev_rx_kill_vid(struct net_device *br_dev, __be16 proto, u16 vid)
>> +{
>> +	br_manage_promisc(netdev_priv(br_dev));
>> +	return 0;
>> +}
>> +
>>  static int br_add_slave(struct net_device *dev, struct net_device *slave_dev)
>>  
>>  {
>> @@ -328,6 +340,8 @@ static const struct net_device_ops br_netdev_ops = {
>>  	.ndo_change_rx_flags	 = br_dev_change_rx_flags,
>>  	.ndo_change_mtu		 = br_change_mtu,
>>  	.ndo_do_ioctl		 = br_dev_ioctl,
>> +	.ndo_vlan_rx_add_vid	 = br_dev_rx_add_vid,
>> +	.ndo_vlan_rx_kill_vid	 = br_dev_rx_kill_vid,
>>  #ifdef CONFIG_NET_POLL_CONTROLLER
>>  	.ndo_netpoll_setup	 = br_netpoll_setup,
>>  	.ndo_netpoll_cleanup	 = br_netpoll_cleanup,
>> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
>> index 7e92bd0..55e4e28 100644
>> --- a/net/bridge/br_if.c
>> +++ b/net/bridge/br_if.c
>> @@ -497,12 +497,21 @@ static void br_port_clear_promisc(struct net_bridge_port *p)
>>  void br_manage_promisc(struct net_bridge *br)
>>  {
>>  	struct net_bridge_port *p;
>> +	int set_all = false;
>> +
>> +	if (br->dev->flags & IFF_PROMISC)
>> +		set_all = true;
>> +
>> +	/* If vlan filtering is disabled and there are any VLANs
>> +	 * configured on top of the bridge, set promisc on all
>> +	 * ports.
>> +	 */
>> +	if (!br_vlan_enabled(br) && vlan_uses_dev(br->dev))
>> +		set_all = true;
>>  
>>  	list_for_each_entry(p, &br->port_list, list) {
>> -		if (br->dev->flags & IFF_PROMISC) {
>> -			/* PROMISC flag has been turned on for the bridge
>> -			 * itself.  Turn on promisc on all ports.
>> -			 */
>> +		if (set_all) {
>> +			/* Set all the ports to promisc mode.  */
>>  			br_port_set_promisc(p);
>>  
>>  		} else {
>> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
>> index 4042f86..87dcc09 100644
>> --- a/net/bridge/br_private.h
>> +++ b/net/bridge/br_private.h
>> @@ -641,6 +641,10 @@ static inline u16 br_get_pvid(const struct net_port_vlans *v)
>>  	return v->pvid ?: VLAN_N_VID;
>>  }
>>  
>> +static inline int br_vlan_enabled(struct net_bridge *br)
>> +{
>> +	return br->vlan_enabled;
>> +}
>>  #else
>>  static inline bool br_allowed_ingress(struct net_bridge *br,
>>  				      struct net_port_vlans *v,
>> @@ -721,6 +725,11 @@ static inline u16 br_get_pvid(const struct net_port_vlans *v)
>>  {
>>  	return VLAN_N_VID;	/* Returns invalid vid */
>>  }
>> +
>> +static inline int br_vlan_enabled(struct net_bridge *br);
>> +{
>> +	return 0;
>> +}
>>  #endif
>>  
>>  /* br_netfilter.c */
>> diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
>> index 8249ca7..eddc2f6 100644
>> --- a/net/bridge/br_vlan.c
>> +++ b/net/bridge/br_vlan.c
>> @@ -321,6 +321,7 @@ int br_vlan_filter_toggle(struct net_bridge *br, unsigned long val)
>>  		goto unlock;
>>  
>>  	br->vlan_enabled = val;
>> +	br_manage_promisc(br);
>>  
>>  unlock:
>>  	rtnl_unlock();
>> -- 
>> 1.8.5.3