From: Mike Manning <mmanning@brocade•com>
To: Michal Kubecek <mkubecek@suse•cz>
Cc: netdev <netdev@vger•kernel.org>
Subject: Re: [PATCH net v4] vlan: Propagate MAC address to VLANs
Date: Mon, 9 May 2016 13:19:47 +0100 [thread overview]
Message-ID: <57308063.8000006@brocade.com> (raw)
In-Reply-To: <20160509064825.GA27709@unicorn.suse.cz>
On 05/09/2016 07:48 AM, Michal Kubecek wrote:
> 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 <mmanning@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
>
Thanks for your review and this excellent catch. I will add address
notification for the vlan itself and test appropriately for when an upper
device is present.
>> /* 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
>
Thanks. Yes, I was aware of this but decided not to change it to keep the
changeset to a minimum. I will make the change as recommended.
>> + }
>> if (is_zero_ether_addr(dev->broadcast))
>> memcpy(dev->broadcast, real_dev->broadcast, dev->addr_len);
>>
>> --
>> 1.7.10.4
>>
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prev parent reply other threads:[~2016-05-09 12:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <572DB364.2040109@brocade.com>
2016-05-07 10:00 ` [PATCH net v4] vlan: Propagate MAC address to VLANs Mike Manning
2016-05-09 6:48 ` Michal Kubecek
2016-05-09 12:19 ` Mike Manning [this message]
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