| title: | Re IPoIB Identify multicast packets and fi |
|
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 <cl@xxxxxxxxx
---
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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