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.
Subject: [IPoIB] Identify multicast packets and fix IGMP breakage V3
IGMP processing is broken because the IPOIB does not set the
skb->pkt_type the right way for Multicast traffic. All incoming
packets are set to PACKET_HOST which means that the igmp_recv()
function will ignore the IGMP broadcasts/multicasts.
This in turn means that the IGMP timers are firing and are sending
information about multicast subscriptions unnecessarily. In a large
private network this can cause traffic spikes.
Signed-off-by: Christoph Lameter <c...@linux.com>
---
Index: linux-2.6/drivers/infiniband/ulp/ipoib/ipoib_ib.c
===================================================================
--- linux-2.6.orig/drivers/infiniband/ulp/ipoib/ipoib_ib.c 2010-08-26
18:24:07.842079559 -0500
+++ linux-2.6/drivers/infiniband/ulp/ipoib/ipoib_ib.c 2010-08-26
18:25:33.859815544 -0500
@@ -271,6 +271,14 @@
ipoib_ud_dma_unmap_rx(priv, mapping);
ipoib_ud_skb_put_frags(priv, skb, wc->byte_len);
+ /* First byte of dgid signals multicast when 0xff */
+ if ((wc->wc_flags & IB_WC_GRH) &&
+ ((struct ib_grh *)skb->data)->dgid.raw[0] == 0xff)
+
+ skb->pkt_type = PACKET_MULTICAST;
+ else
+ skb->pkt_type = PACKET_HOST;
+
skb_pull(skb, IB_GRH_BYTES);
skb->protocol = ((struct ipoib_header *) skb->data)->proto;
@@ -281,9 +289,6 @@
dev->stats.rx_bytes += skb->len;
skb->dev = dev;
- /* XXX get correct PACKET_ type here */
- skb->pkt_type = PACKET_HOST;
-
if (test_bit(IPOIB_FLAG_CSUM, &priv->flags) && likely(wc->csum_ok))
skb->ip_summed = CHECKSUM_UNNECESSARY;
--
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