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

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 26 Feb 2014 18:25:39 +0200

On Wed, Feb 26, 2014 at 11:05:40AM -0500, Vlad Yasevich wrote:
> 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

Need to check if there are port list walks there anyway.
If yes then it doesn't matter much I think.

> > 
> > 
> >> ---
> >>  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