[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, 7 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c6efce4a04a4..936f8b76114e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -927,6 +927,13 @@ extern int		netdev_max_backlog;
 extern int              weight_p;
 extern int              netdev_set_master(struct net_device *dev, struct net_device *master);
 extern int skb_checksum_help(struct sk_buff *skb, int inward);
+#ifdef CONFIG_BUG
+extern void netdev_rx_csum_fault(struct net_device *dev);
+#else
+static inline void netdev_rx_csum_fault(struct net_device *dev)
+{
+}
+#endif
 /* rx skb timestamps */
 extern void             net_enable_timestamp(void);
 extern void             net_disable_timestamp(void);