[NET]: IPV6 checksum offloading in network devices

The existing model for checksum offload does not correctly handle
devices that can offload IPV4 and IPV6 only. The NETIF_F_HW_CSUM flag
implies device can do any arbitrary protocol.

This patch:
 * adds NETIF_F_IPV6_CSUM for those devices
 * fixes bnx2 and tg3 devices that need it
 * add NETIF_F_IPV6_CSUM to ipv6 output (incl GSO)
 * fixes assumptions about NETIF_F_ALL_CSUM in nat
 * adjusts bridge union of checksumming computation

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 3 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index ee051bb398a0..a0a46e7ed137 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1509,9 +1509,11 @@ int dev_queue_xmit(struct sk_buff *skb)
                 skb_set_transport_header(skb, skb->csum_start -
                                               skb_headroom(skb));
 
-                if (!(dev->features & NETIF_F_GEN_CSUM) &&
-                    (!(dev->features & NETIF_F_IP_CSUM) ||
-                     skb->protocol != htons(ETH_P_IP)))
+                if (!(dev->features & NETIF_F_GEN_CSUM)
+                    || ((dev->features & NETIF_F_IP_CSUM)
+                        && skb->protocol == htons(ETH_P_IP))
+                    || ((dev->features & NETIF_F_IPV6_CSUM)
+                        && skb->protocol == htons(ETH_P_IPV6)))
                         if (skb_checksum_help(skb))
                                 goto out_kfree_skb;
         }
@@ -3107,6 +3109,22 @@ int register_netdevice(struct net_device *dev)
                 }
         }
 
+        /* Fix illegal checksum combinations */
+        if ((dev->features & NETIF_F_HW_CSUM) &&
+            (dev->features & (NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))) {
+                printk(KERN_NOTICE "%s: mixed HW and IP checksum settings.\n",
+                       dev->name);
+                dev->features &= ~(NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM);
+        }
+
+        if ((dev->features & NETIF_F_NO_CSUM) &&
+            (dev->features & (NETIF_F_HW_CSUM|NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM))) {
+                printk(KERN_NOTICE "%s: mixed no checksumming and other settings.\n",
+                       dev->name);
+                dev->features &= ~(NETIF_F_IP_CSUM|NETIF_F_IPV6_CSUM|NETIF_F_HW_CSUM);
+        }
+
+
         /* Fix illegal SG+CSUM combinations. */
         if ((dev->features & NETIF_F_SG) &&
             !(dev->features & NETIF_F_ALL_CSUM)) {