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

From: Vlad Yasevich <[email-masked]>
Date: Thu, 27 Feb 2014 08:17:08 -0500

On 02/27/2014 07:06 AM, Toshiaki Makita wrote:
> (2014/02/27 0:18), 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.
> 
> If we disable vlan_filtering and no vlan interface is configured on the
> bridge, we cannot forward any tagged traffic?

We can't receive tagged traffic, so we turn promisc on.

> If we want to forward frames from one port to another port (not from/to
> bridge device), we have to add vlan interface or set promisc mode, right?
> 

Hm..  Good point.  This isn't enough to address the scenario that Patch7
tries to solve.  I'll need to think about that.  This is partially why
I split functionality in Patch7 out.  It made things more difficult.

-vlad

> Sorry if I misunderstood it. I'm not sure..
> 
> Thanks,
> Toshiaki Makita
> 
>>
>> Signed-off-by: Vlad Yasevich <[email-masked]>
>> ---
>>  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();
>>