-----"Jason Gunthorpe" <jgg@xxxxxxxx> wrote: ----- >To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx> >From: "Jason Gunthorpe" <jgg@xxxxxxxx> >Date: 02/16/2021 07:12PM >Cc: "Chuck Lever" <chuck.lever@xxxxxxxxxx>, "linux-rdma" ><linux-rdma@xxxxxxxxxxxxxxx>, "Benjamin Coddington" ><bcodding@xxxxxxxxxx> >Subject: [EXTERNAL] Re: directing soft iWARP traffic through a secure >tunnel > >On Tue, Feb 16, 2021 at 12:27:33PM +0000, Bernard Metzler wrote: > >> rdma_port_get_link_layer(). Asking the RDMA core experts - >> would a gid of zero have any side effects or bad implications, >> since that ID is by no means unique? > >Yeah, it is clearly not ok. Generate a random private GUID? > Right. But that's unfortunately not sufficient to get devices w/o hardware addresses handled by the CM code. The net_device remains w/o HW address, and that is where CM gets the source HW address from (rdma_copy_src_l2_addr() etc.). I don't have a good idea yet how to get it working. Actually, all this GID and GUID and friends for iWARP CM looks more like squeezing things into InfiniBand terms, where we could just rely on plain ARP and IP (ARP resolve interface, see if there is an RDMA device bound to, done)... or do I miss something? On another related topic - the RDMA CM should let the provider know if an IPv6 address is to be bound AFONLY. This becomes needed in the current NFS/RDMA over iWarp case, where NFS listeners bind to both IPv4 and IPv6 address with same port number. The code correctly calls rdma_set_afonly() on the cmid, but there is no mechanic to pass that information down to the provider. So the second bind fails. I'll send a small patch which enables that for iwcm and siw, hoping for acceptance. Many thanks, Bernard.
