Re: [PATCH v2] bonding: send IPv6 neighbor advertisement on failover

[Jay Vosburgh <fubar@us.ibm.com>]

Brian Haley <brian.haley@hp.com> wrote:

>Hi Jay,
>
>Did you ever get a chance to look at this patch?  Now that net-next is
>open I'd like to resubmit it.

	I'm good with it; I'm merging it with a couple of other feature
things and I'll post it with that set in a day or two when things open
(unless I missed a mail, I don't think net-next is open as I type this).

	-J

---
	-Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com


>Thanks,
>
>-Brian
>
>Brian Haley wrote:
>> Updated to address Vlad's comment about storing the link-local IPv6
>> address in the bond/vlan structure, I no longer overwrite the existing
>> address with a newer one.  Also added missed locking for the inet6_dev.
>>
>> I don't see any way to address David Steven's comment since there is
>> currently no NA tunable in the IPv6 code.
>>
>> ---
>>
>> This patch adds better IPv6 failover support for bonding devices,
>> especially when in active-backup mode and there are only IPv6 addresses
>> configured, as reported by Alex Sidorenko.
>>
>> - Creates a new file, net/drivers/bonding/bond_ipv6.c, for the
>>   IPv6-specific routines.  Both regular bonds and VLANs over bonds
>>   are supported.
>>
>> - Adds a new tunable, num_unsol_na, to limit the number of unsolicited
>>   IPv6 Neighbor Advertisements that are sent on a failover event.
>>   Default is 1.
>>
>> - Creates two new IPv6 neighbor discovery functions:
>>
>>   ndisc_build_skb()
>>   ndisc_send_skb()
>>
>>   These were required to support VLANs since we have to be able to
>>   add the VLAN id to the skb since ndisc_send_na() and friends
>>   shouldn't be asked to do this.  These two routines are basically
>>   __ndisc_send() split into two pieces, in a slightly different order.
>>
>> - Updates Documentation/networking/bonding.txt and bumps the rev of bond
>>   support to 3.4.0.
>>
>> On failover, this new code will generate one packet:
>>
>> - An unsolicited IPv6 Neighbor Advertisement, which helps the switch
>>   learn that the address has moved to the new slave.
>>
>> Testing has shown that sending just the NA results in pretty good
>> behavior when in active-back mode, I saw no lost ping packets for example.
>>
>> -Brian
>>
>> Signed-off-by: Brian Haley <brian.haley@hp.com>
>> ---
>>
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