virtio: Implement skb_partial_csum_set, for setting partial csums on untrusted packets.

Use it in virtio_net (replacing buggy version there), it's also going
to be used by TAP for partial csum support.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 10 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5413dbf3d4ac..a60505c8f82a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -83,17 +83,8 @@ static void receive_skb(struct net_device *dev, struct sk_buff *skb,
 
         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
                 pr_debug("Needs csum!\n");
-                skb->ip_summed = CHECKSUM_PARTIAL;
-                skb->csum_start = hdr->csum_start;
-                skb->csum_offset = hdr->csum_offset;
-                if (skb->csum_start > skb->len - 2
-                    || skb->csum_offset > skb->len - 2) {
-                        if (net_ratelimit())
-                                printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
-                                       dev->name, skb->csum_start,
-                                       skb->csum_offset, skb->len);
+                if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
                         goto frame_err;
-                }
         }
 
         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {