From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [IPoIB] Identify multicast packets and fix IGMP breakage V3 Date: Thu, 26 Aug 2010 17:43:42 -0600 Message-ID: <20100826234342.GA24333@obsidianresearch.com> References: <20100826.151553.242147157.davem@davemloft.net> <20100826222146.GA23025@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ogerlitz-smomgflXvOZWk0Htik3J/w@public.gmane.org, yosefe-smomgflXvOZWk0Htik3J/w@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Lameter Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Thu, Aug 26, 2010 at 06:26:58PM -0500, Christoph Lameter wrote: > On Thu, 26 Aug 2010, Jason Gunthorpe wrote: > > > The 40 bytes at this location are defined by the HW specification to > > be an IB GRH which has an identical layout to an IPv6 header. Roland > > is right, it would be clearer to use ib_grh ->dgid > > Ok but then we have no nice function that checks for multicast anymore. Were you going to try it this way? /* First byte of dgid signals multicast/broadcast when 0xff */ if ((wc->wc_flags & IB_WC_GRH) && ((struct ib_grh *)skb->data)->dgid.raw[0] == 0xff) { if (memcmp(((struct ib_grh *)skb->data)->dgid.raw, dev->broadcast + 4, sizeof(union ib_gid)) == 0) skb->pkt_type = PACKET_BROADCAST; else skb->pkt_type = PACKET_MULTICAST; } else skb->pkt_type = PACKET_HOST; I think doing the memcmp only in the multicast path should be reasonable overhead wise. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html