[openib-general] IPoIB Loading and Starting

[Hal Rosenstock]

On Mon, 2004-09-27 at 15:15, Roland Dreier wrote:
>     Hal> That's the section I was referring to too. Doesn't C15-0.2-1
>     Hal> restrict the SA GetTableResp to only include multicast groups
>     Hal> for Pkeys on that port ? I am interpreting the subject node
>     Hal> is the same as the requesting node in this case. What are you
>     Hal> referring to ?
> 
> Hmm, I don't have C15-0.2-1 in my spec.

This is from IBA 1.2. 

>   I was going by the following:
> 
>     C15-0.1.22: When a requester node requests data from the Subnet
>     Administrator that would provide information about a subject node,
>     the Subnet Administrator shall return only data providing
>     information about subject nodes for which the requester shares a
>     P_Key, with exceptions noted below in C15-0.1.23.
> 
> which doesn't seem to restrict the MC groups that a query can return,

At IBA 1.2, C15-0.1.22 is obsolete and has been replaced by C15-0.2.1.
C15-0.2.1: When a requester node sends a trusted request to SA, the re- 
quested data shall be returned. When a requester node sends a non-
trusted request for data to SA that would provide information about a
subject node, the SA shall return only data providing information about
subject nodes for which the requester shares a P_Key, with exceptions
noted below in C15-0.1.23.

So this appears to be a 1.2/1.1 difference. With 1.1, the local node
would need to filter for groups for which the port had full PKey.

> as well as:
> 
>     C15-0.1.23: [...] MCMemberRecords shall always be provided with
>     the PortGID, Join- State and ProxyJoin components set to 0, except
>     for the case of a trusted request, in which case the actual
>     component contents shall be provided.
> 
> which seems to imply that MCMemberRecords will just have the subject
> node info zeroed out.

I think that the PKey sharing is a first level check before this would 
occur in the SA response.

>     Hal> Aren't there separate IP interfaces in Linux for either IPv4
>     Hal> or IPv6 ?  That's what I meant by IP interface type. Maybe
>     Hal> I'm not using the proper terminology. The IPoIB signatures
>     Hal> appear in the MGID of the multicast group and are 0x401B for
>     Hal> IPv4 and 0x601B for IPv6 per the IETF I-D.
> 
> Nope, a network interface in Linux can carry all kinds of
> packets... IPv4, IPv6, IPX, Appletalk, etc.  It can have any arbitrary
> collection of IPv4 and IPv6 addresses assigned at any time...

Aren't there separate network interfaces for IPv4 and IPv6 on top of
some lower layer IB interface ?

In any case, for an IB interface, One way IPoIB "auto" discovery could
work is to bring up IPv4 and IPv6 depending on which groups were present
for the groups pertaining to the port's (full) PKeys unless configured 
otherwise.

In practicality, all multicast groups are likely IPoIB. The only issue
is whether they are IPv4 or IPv6 groups and whether the groups are
groups that the port can participate in (full PKey 1.2/1.1 difference).

-- Hal