/** * 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; }