Re: [PATCH 1/2] ibacm: Incorrect usage of BE byte order of MLID attach/detach_mcast()

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Fri, Oct 13, 2017 at 02:43:47PM -0400, Michael J. Ruhl wrote:
> From: Michael J. Ruhl <michael.j.ruhl-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>
> The MLID value passed to ibv_attach/detach_mcast() must be in host
> byte order.
>
> acmp.c incorrectly uses the big endian format when doing a multicast
> attach/detach (join). Multicast packets are used to do name resolution
> by the libibacmp library.
>
> There are two possible results because of this issue.
>
> If a kernel has commit 00b8a3351b2b, the attach will fail with an
> EINVAL.  ibacm will log this as a failure during the multicast join.

Kernel doesn't have such commit.
https://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma.git/commit/?h=k.o/for-next&id=00b8a3351b2b

>
> If a kernel does not have commit 00b8a3351b2b, the attach will
> complete successfully.  Packets sent to this address will be dropped
> because the packet dlid value and the multicast address information
> given by the attach will not match.
>
> Update MLID usage to use the correct byte order.
>
> Reviewed-by: Mike Marciniszyn <mike.marciniszyn-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Michael J. Ruhl <michael.j.ruhl-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
>  ibacm/prov/acmp/src/acmp.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/ibacm/prov/acmp/src/acmp.c b/ibacm/prov/acmp/src/acmp.c
> index aa78416..78d9a29 100644
> --- a/ibacm/prov/acmp/src/acmp.c
> +++ b/ibacm/prov/acmp/src/acmp.c
> @@ -732,7 +732,7 @@ static void acmp_process_join_resp(struct acm_sa_mad *sa_mad)
>  			acm_log(0, "ERROR - unable to create ah\n");
>  			goto out;
>  		}
> -		ret = ibv_attach_mcast(ep->qp, &mc_rec->mgid, mc_rec->mlid);
> +		ret = ibv_attach_mcast(ep->qp, &dest->mgid, dest->av.dlid);
>  		if (ret) {
>  			acm_log(0, "ERROR - unable to attach QP to multicast group\n");
>  			ibv_destroy_ah(dest->ah);
> @@ -1429,7 +1429,7 @@ static void acmp_ep_join(struct acmp_ep *ep)
>
>  	if (ep->mc_dest[0].state == ACMP_READY && ep->mc_dest[0].ah) {
>  		ibv_detach_mcast(ep->qp, &ep->mc_dest[0].mgid,
> -				 be16toh(ep->mc_dest[0].av.dlid));
> +				 ep->mc_dest[0].av.dlid);
>  		ibv_destroy_ah(ep->mc_dest[0].ah);
>  		ep->mc_dest[0].ah = NULL;
>  	}
>
> --
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