Re: [PATCH net-next 3/6] net: 8021q: vlan_dev: add vid tag for vlan device own address

[Ivan Khoronzhuk]

On Wed, Feb 27, 2019 at 08:13:34PM -0800, Florian Fainelli wrote:
> On 2/26/2019 10:45 AM, Ivan Khoronzhuk wrote:
> > The vlan device address is held separately from uc/mc lists and
> > handled differently. The vlan dev address is bound with real device
> > address only if it's inherited from init, in all other cases it's
> > separate address entry in uc list. With vid set, the address becomes
> > not inherited from real device after it's set manually as before, but
> > is part of uc list any way, with appropriate vid tag set. If vid_len
> > for real device is 0, the behaviour is the same as before this change,
> > so shouldn't be any impact on systems w/o individual virtual device
> > filtering (IVDF) enabled. This allows to control and sync vlan device
> > address and disable concrete vlan packet income when vlan interface is
> > down.
> >
> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
> > ---
>
> [snip]
>
> > +static int vlan_dev_add_addr(struct net_device *dev, u8 *addr)
> > +{
> > +	struct net_device *real_dev = vlan_dev_real_dev(dev);
> > +	unsigned char naddr[ETH_ALEN + NET_8021Q_VID_TSIZE];
> > +
> > +	if (real_dev->vid_len) {
>
> Don't you need to check that real_dev->vid_len is >= NET_8021Q_VID_TSIZE
> here?

vid_len for all eth devices or 0 or NET_8021Q_VID_TSIZE and used here only as
a flag that different addressing scheme is used.
vlan_dev_set_addr_vid() do copy only < NET_8021Q_VID_TSIZE anyway.

Can add the following to be sure:
if (real_dev->vid_len) {
	if (real_dev->vid_len != NET_8021Q_VID_TSIZE)
		return -1;
	....
}

But frankly, if this happens the system is ill and this check can't help it.


> > +		memcpy(naddr, addr, dev->addr_len);
> > +		vlan_dev_set_addr_vid(dev, naddr);
> > +		return dev_vid_uc_add(real_dev, naddr);
> > +	}
> > +
> > +	if (ether_addr_equal(addr, real_dev->dev_addr))
> > +		return 0;
> > +
> > +	return dev_uc_add(real_dev, addr);
> > +}
> > +
> > +static void vlan_dev_del_addr(struct net_device *dev, u8 *addr)
> > +{
> > +	struct net_device *real_dev = vlan_dev_real_dev(dev);
> > +	unsigned char naddr[ETH_ALEN + NET_8021Q_VID_TSIZE];
> > +
> > +	if (real_dev->vid_len) {
>
> Same here.

Not same, it's void routine.
And del can't happen w/o add, no reason.

> > +		memcpy(naddr, addr, dev->addr_len);
> > +		vlan_dev_set_addr_vid(dev, naddr);
> > +		dev_vid_uc_del(real_dev, naddr);
> > +		return;
> > +	}
> > +
> > +	if (!ether_addr_equal(dev->dev_addr, real_dev->dev_addr))
> > +		dev_uc_del(real_dev, addr);
> > +}
> > +
> > +static int vlan_dev_subs_addr(struct net_device *dev, u8 *addr)
> > +{
> > +	int err;
> > +
> > +	err = vlan_dev_add_addr(dev, addr);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	vlan_dev_del_addr(dev, dev->dev_addr);
> > +	return err;
> > +}
> > +
> >  bool vlan_dev_inherit_address(struct net_device *dev,
> >  			      struct net_device *real_dev)
> >  {
> >  	if (dev->addr_assign_type != NET_ADDR_STOLEN)
> >  		return false;
> >
> > +	if (real_dev->vid_len)
> > +		if (vlan_dev_subs_addr(dev, real_dev->dev_addr))
> > +			return false;
>
> The check on real_dev->vid_len can be absorbed into vlan_dev_subs_addr()?

No, I'd tried. vlan_dev_subs_addr() is used not only here and move it under
makes more not combined code.

> > +
> >  	ether_addr_copy(dev->dev_addr, real_dev->dev_addr);
> >  	call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
> >  	return true;
> > @@ -278,9 +327,10 @@ static int vlan_dev_open(struct net_device *dev)
> >  	    !(vlan->flags & VLAN_FLAG_LOOSE_BINDING))
> >  		return -ENETDOWN;
> >
> > -	if (!ether_addr_equal(dev->dev_addr, real_dev->dev_addr) &&
> > -	    !vlan_dev_inherit_address(dev, real_dev)) {
> > -		err = dev_uc_add(real_dev, dev->dev_addr);
> > +	if (ether_addr_equal(dev->dev_addr, real_dev->dev_addr) ||
> > +	    (!ether_addr_equal(dev->dev_addr, real_dev->dev_addr) &&
> > +	     !vlan_dev_inherit_address(dev, real_dev))) {
>
> Should this condition simply become if !vlan_dev_inherit_address() now?

It can't, I'd tried.
vlan_dev_inherit_address() is used in (vlan.c):
vlan_sync_address(struct net_device *dev, struct net_device *vlandev);

--
Regards,
Ivan Khoronzhuk