Re: issues with the rdma-cm server side mapping of IP to GID

[Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

On 02/03/2014 01:50, Hefty, Sean wrote:
>> Such situation can happen in the following cases:
>>
>> 1. net.ipv4.conf.default.arp_ignore equals 0 (the default)
>> 2. server side bonding/teaming fail-over when the Gratitous ARP sent was
>> lost
>> 3. re-order of ibM net-devices mapping to HCA PCI devices after server
>> boot/crash
>> 4. etc more
>>
>> Basically, when the rdma-cm observes difference between the destination GID as present in the IB path within the CM REQ to the one resolved locally,  we should at least print a warning. Perhaps, we should reject the connection request? (in that case, I wasn't sure what would be the appropriate reject reason), any more ideas?
> I'm not sure that this results in a single error case.

Sorry... I'm not sure to follow, can you elaborate a bit more?

> Can the kernel rdma_cm check for net.ipv4.default.arp_ignore on startup and at least print a warning if that is wrong?

I am not sure, and anyway, please note that I brought at least two more 
use cases where the problem happens

- following server side bonding fail-over

- following server side reboot after which the PCI ordering changes 
between two HCAs and hence ibM devices change their PCI association

Or.


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