Our code that handles checksumming does essentially the same thing
as skb_checksum_help() except it folds the process into copying to
userspace. This makes the two functions more closely resemble
each other in structure, including adding a couple of BUG() checks.
This should have no functional change but makes comparision easier
when debugging.
int csum_start, csum_offset;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
int csum_start, csum_offset;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
- /* Until 2.6.22, the start of the transport header was
- * also the start of data to be checksummed. Linux
- * 2.6.22 introduced the csum_start field for this
- * purpose, but we should point the transport header to
- * it anyway for backward compatibility, as
- * dev_queue_xmit() does even in 2.6.28. */
- skb_set_transport_header(skb, skb->csum_start - skb_headroom(skb));
+ csum_start = skb->csum_start - skb_headroom(skb);
csum_offset = skb->csum_offset;
#else
csum_offset = skb->csum_offset;
#else
+ csum_start = skb_transport_header(skb) - skb->data;
csum_offset = skb->csum;
#endif
csum_offset = skb->csum;
#endif
- csum_start = skb_transport_header(skb) - skb->data;
+ BUG_ON(csum_start >= skb_headlen(skb));
retval = skb_copy_and_csum_datagram(skb, csum_start, buf + csum_start,
copy_bytes - csum_start, &csum);
if (!retval) {
retval = skb_copy_and_csum_datagram(skb, csum_start, buf + csum_start,
copy_bytes - csum_start, &csum);
if (!retval) {
copy_bytes = csum_start;
csump = (__sum16 __user *)(buf + csum_start + csum_offset);
copy_bytes = csum_start;
csump = (__sum16 __user *)(buf + csum_start + csum_offset);
+
+ BUG_ON((char *)csump + sizeof(__sum16) > buf + nbytes);
put_user(csum_fold(csum), csump);
}
} else
put_user(csum_fold(csum), csump);
}
} else