On Sat, May 07, 2016 at 11:00:09AM +0100, Mike Manning wrote:
> The MAC address of the physical interface is only copied to the VLAN
> when it is first created, resulting in an inconsistency after MAC
> address changes of only newly created VLANs having an up-to-date MAC.
>
> The VLANs should continue inheriting the MAC address of the physical
> interface until the VLAN MAC address is explicitly set to any value.
> This allows IPv6 EUI64 addresses for the VLAN to reflect any changes
> to the MAC of the physical interface and thus for DAD to behave as
> expected.
>
> Signed-off-by: Mike Manning <mmann...@brocade.com>
> ---
> net/8021q/vlan.c | 7 +++++++
> net/8021q/vlan_dev.c | 14 ++++++++++----
> 2 files changed, 17 insertions(+), 4 deletions(-)
>
> --- a/net/8021q/vlan.c
> +++ b/net/8021q/vlan.c
> @@ -291,6 +291,12 @@ static void vlan_sync_address(struct net
> if (ether_addr_equal(vlan->real_dev_addr, dev->dev_addr))
> return;
>
> + /* vlan continues to inherit address of parent interface */
> + if (vlandev->addr_assign_type == NET_ADDR_STOLEN) {
> + ether_addr_copy(vlandev->dev_addr, dev->dev_addr);
> + goto out;
> + }
> +
I might have missed something in the previous discussion but as
ether_addr_copy() is just an optimized memcpy(), how is this going to
handle the setups where the vlan device itself has an upper device? For
example,
- if it is a bridge port, how is the bridge going to learn about its
address change so that it can update its FDB?
- if it is a bond slave or team port, current code preserves the vlan
device address on real device change so everything is fine; your
proposal would change vlan device's address without bond being even
notified, I believe
- there might be a macvlan on top of the vlan and you might
accidentally match its address with the new one
> /* vlan address was different from the old address and is equal to
> * the new address */
> if (!ether_addr_equal(vlandev->dev_addr, vlan->real_dev_addr) &&
> @@ -303,6 +309,7 @@ static void vlan_sync_address(struct net
> !ether_addr_equal(vlandev->dev_addr, dev->dev_addr))
> dev_uc_add(dev, vlandev->dev_addr);
>
> +out:
> ether_addr_copy(vlan->real_dev_addr, dev->dev_addr);
> }
>
> --- a/net/8021q/vlan_dev.c
> +++ b/net/8021q/vlan_dev.c
> @@ -255,9 +255,13 @@ static int vlan_dev_open(struct net_devi
> return -ENETDOWN;
>
> if (!ether_addr_equal(dev->dev_addr, real_dev->dev_addr)) {
> - err = dev_uc_add(real_dev, dev->dev_addr);
> - if (err < 0)
> - goto out;
> + if (dev->addr_assign_type == NET_ADDR_STOLEN) {
> + ether_addr_copy(dev->dev_addr, real_dev->dev_addr);
The same question here.
> + } else {
> + err = dev_uc_add(real_dev, dev->dev_addr);
> + if (err < 0)
> + goto out;
> + }
> }
>
> if (dev->flags & IFF_ALLMULTI) {
> @@ -558,8 +562,10 @@ static int vlan_dev_init(struct net_devi
> /* ipv6 shared card related stuff */
> dev->dev_id = real_dev->dev_id;
>
> - if (is_zero_ether_addr(dev->dev_addr))
> + if (is_zero_ether_addr(dev->dev_addr)) {
> eth_hw_addr_inherit(dev, real_dev);
> + dev->addr_assign_type = NET_ADDR_STOLEN;
You might want to replace eth_hw_addr_inherit() with ether_addr_copy()
here as they only differ in the former copying addr_assign_type which
you are going to rewrite anyway. (But as both are most likely inlined,
I would expect the resulting code to be the same in the end.)
Michal Kubecek
> + }
> if (is_zero_ether_addr(dev->broadcast))
> memcpy(dev->broadcast, real_dev->broadcast, dev->addr_len);
>
> --
> 1.7.10.4
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