On Thu, Sep 13, 2018 at 4:00 PM, Michal Soltys <sol...@ziu.info> wrote:
> On 2018-07-19 18:20, Michal Soltys wrote:
>> On 07/19/2018 01:41 AM, Mahesh Bandewar wrote:
>>> From: Mahesh Bandewar <mahe...@google.com>
>>>
>>> Commit b89f04c61efe ("bonding: deliver link-local packets with
>>> skb->dev set to link that packets arrived on") changed the behavior
>>> of how link-local-multicast packets are processed. The change in
>>> the behavior broke some legacy use cases where these packets are
>>> expected to arrive on bonding master device also.
>>>
>>> This patch passes the packet to the stack with the link it arrived
>>> on as well as passes to the bonding-master device to preserve the
>>> legacy use case.
>>>
>>> Fixes: b89f04c61efe ("bonding: deliver link-local packets with
>>> skb->dev set to link that packets arrived on")
>>> Reported-by: Michal Soltys <sol...@ziu.info>
>>> Signed-off-by: Mahesh Bandewar <mahe...@google.com>
>>> ---
>>> v2: Added Fixes tag.
>>> v1: Initial patch.
>>> drivers/net/bonding/bond_main.c | 17 +++++++++++++++--
>>> 1 file changed, 15 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/net/bonding/bond_main.c
>>> b/drivers/net/bonding/bond_main.c
>>> index 9a2ea3c1f949..1d3b7d8448f2 100644
>>> --- a/drivers/net/bonding/bond_main.c
>>> +++ b/drivers/net/bonding/bond_main.c
>>> @@ -1177,9 +1177,22 @@ static rx_handler_result_t
>>> bond_handle_frame(struct sk_buff **pskb)
>>> }
>>> }
>>> - /* don't change skb->dev for link-local packets */
>>> - if (is_link_local_ether_addr(eth_hdr(skb)->h_dest))
>>> + /* Link-local multicast packets should be passed to the
>>> + * stack on the link they arrive as well as pass them to the
>>> + * bond-master device. These packets are mostly usable when
>>> + * stack receives it with the link on which they arrive
>>> + * (e.g. LLDP) but there may be some legacy behavior that
>>> + * expects these packets to appear on bonding master too.
>>
>> I'd really change the comment from:
>>
>> "These packets are mostly usable when stack receives it with the link on
>> which they arrive (e.g. LLDP) but there may be some legacy behavior that
>> expects these packets to appear on bonding master too."
>>
>> to something like:
>>
>> "These packets are mostly usable when stack receives it with the link on
>> which they arrive, but they also must be available on aggregations. Some
>> of the use cases include (but are not limited to): LLDP agents that must
>> be able to operate both on enslaved interfaces as well as on bonds
>> themselves; linux bridges that must be able to process/pass BPDUs from
>> attached bonds when any kind of stp version is enabled on the network."
>>
>> It's a bit longer, but clarifies the reasons more precisely (without
>> going too deep into features like group_fwd_mask).
>>
>
> Anyway, any chance for that patch to get merged ? It would be great to
> get the correct functionality back asap. As for the comment, I'll submit
> a trivial patch expanding/clarifying it later (or I can resubmit
> adjusted v3 if it's ok with Mahesh).
Hmm, didn't notice that it wasn't merged but somehow it fell through
the cracks as it needed my attention earlier. I'll resubmit.
