/**
* skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec.
* @skb: skbuff
* @hlen: hardware length
* @iov: io vector
*
* Caller _must_ check that skb will fit to this iovec.
*
* Returns: 0 - success.
* -EINVAL - checksum failure.
* -EFAULT - fault during copy. Beware, in this case iovec
* can be modified!
*/
int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
int hlen, struct iovec *iov)
{
__wsum csum;
int chunk = skb->len - hlen;
/* Skip filled elements.
* Pretty silly, look at memcpy_toiovec, though 8)
*/
while (!iov->iov_len)
iov++;
if (iov->iov_len < chunk) {
if (__skb_checksum_complete(skb))
goto csum_error;
if (skb_copy_datagram_iovec(skb, hlen, iov, chunk))
goto fault;
} else {
csum = csum_partial(skb->data, hlen, skb->csum);
if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base,
chunk, &csum))
goto fault;
if (csum_fold(csum))
goto csum_error;
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
netdev_rx_csum_fault(skb->dev);
iov->iov_len -= chunk;
iov->iov_base += chunk;
}
return 0;
csum_error:
return -EINVAL;
fault:
return -EFAULT;
}
__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
{
__sum16 sum;
sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
if (likely(!sum)) {
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
netdev_rx_csum_fault(skb->dev);
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
return sum;
}
/* Compute the whole skb csum in s/w and store it, then verify GRO csum
* starting from gro_offset.
*/
static __sum16 gro_skb_checksum(struct sk_buff *skb)
{
__sum16 sum;
skb->csum = skb_checksum(skb, 0, skb->len, 0);
NAPI_GRO_CB(skb)->csum = csum_sub(skb->csum,
csum_partial(skb->data, skb_gro_offset(skb), 0));
sum = csum_fold(NAPI_GRO_CB(skb)->csum);
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) {
if (unlikely(!sum))
netdev_rx_csum_fault(skb->dev);
} else
skb->ip_summed = CHECKSUM_COMPLETE;
return sum;
}
