[NET]: Detect hardware rx checksum faults correctly

Here is the patch that introduces the generic skb_checksum_complete
which also checks for hardware RX checksum faults.  If that happens,
it'll call netdev_rx_csum_fault which currently prints out a stack
trace with the device name.  In future it can turn off RX checksum.

I've converted every spot under net/ that does RX checksum checks to
use skb_checksum_complete or __skb_checksum_complete with the
exceptions of:

* Those places where checksums are done bit by bit.  These will call
netdev_rx_csum_fault directly.

* The following have not been completely checked/converted:

ipmr
ip_vs
netfilter
dccp

This patch is based on patches and suggestions from Stephen Hemminger
and David S. Miller.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 175e093ec564..e3eceecd0496 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -934,11 +934,11 @@ int icmp_rcv(struct sk_buff *skb)
         case CHECKSUM_HW:
                 if (!(u16)csum_fold(skb->csum))
                         break;
-                LIMIT_NETDEBUG(KERN_DEBUG "icmp v4 hw csum failure\n");
+                /* fall through */
         case CHECKSUM_NONE:
-                if ((u16)csum_fold(skb_checksum(skb, 0, skb->len, 0)))
+                skb->csum = 0;
+                if (__skb_checksum_complete(skb))
                         goto error;
-        default:;
         }
 
         if (!pskb_pull(skb, sizeof(struct icmphdr)))