> On 16 Nov 2017, at 09:30, Erez Shitrit <erezsh@xxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Nov 15, 2017 at 5:39 PM, Jason Gunthorpe <jgg@xxxxxxxx> wrote:
>> On Wed, Nov 15, 2017 at 09:01:07AM +0200, Erez Shitrit wrote:
>>>>> if (!IS_ERR_OR_NULL(ah)) {
>>>>> + /* check there is no mismatch from the request */
>>>>> + if (memcmp(pathrec->dgid.raw, path->pathrec.dgid.raw,
>>>>> + sizeof(union ib_gid))) {
>>>>> + pr_warn("%s got PathRec for gid %pI6 while asked for %pI6\n",
>>>>> + dev->name, pathrec->dgid.raw, path->pathrec.dgid.raw);
>>>>> + /* overwrite the response from the sm before copy to the db */
>>>>> + memcpy(pathrec->dgid.raw, path->pathrec.dgid.raw,
>>>>> + sizeof(union ib_gid));
>>>>
>>>> This doesn't seem like it should be a warning, and replacing the
>>>> good DGID from the SA with local garbage seems really wrong.
>>>
>>> IPoIB is L2 driver and should act as a pipe and cannot add its opinion
>>> about what is a good or a garbage GID.
>>
>> Which is why ipoib should not override the result from the SA.
>
> It override only the DGID in the record, and that for IPoIB uses only,
> not the ah which is the important.
> otherwise if the host will re-ask again for that DGID it will not be
> found in IPoIB database, and new record will be created and so on till
> the end of all the device memory.
Isn’t the correct solution to mask away the 16-bit subnet prefix when looking up a unicast DGID in the database?
Thxs, Håkon
>
>>
>> It needs to work in a way where it looks up a DGID from the LLADDR and
>> gets back a wire GRH and LRH which come from SA.
>
> For that there is the ah object, this object is used as it came from the SA.
>
>>
>>> If the host is asking for specific mac address, IPoIB should return
>>> the response for the original request/mac and should not decide what
>>> is good for the host.
>>
>> No, it is up to the SA to return the GRH to put in the packets, it
>> should never be changed in any way by a ULP.
>
> The change is only for the ULP, the user/host has no idea of that, and
> it gets the same ah that came from the SA.
>
>>
>> Jason
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