/**
* skb_copy_datagram_iovec - Copy a datagram to an iovec.
* @skb: buffer to copy
* @offset: offset in the buffer to start copying from
* @to: io vector to copy to
* @len: amount of data to copy from buffer to iovec
*
* Note: the iovec is modified during the copy.
*/
int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
struct iovec *to, int len)
{
int start = skb_headlen(skb);
int i, copy = start - offset;
struct sk_buff *frag_iter;
trace_skb_copy_datagram_iovec(skb, len);
/* Copy header. */
if (copy > 0) {
if (copy > len)
copy = len;
if (memcpy_toiovec(to, skb->data + offset, copy))
goto fault;
if ((len -= copy) == 0)
return 0;
offset += copy;
}
/* Copy paged appendix. Hmm... why does this look so complicated? */
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
int end;
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
WARN_ON(start > offset + len);
end = start + skb_frag_size(frag);
if ((copy = end - offset) > 0) {
int err;
u8 *vaddr;
struct page *page = skb_frag_page(frag);
if (copy > len)
copy = len;
vaddr = kmap(page);
err = memcpy_toiovec(to, vaddr + frag->page_offset +
offset - start, copy);
kunmap(page);
if (err)
goto fault;
if (!(len -= copy))
return 0;
offset += copy;
}
start = end;
}
skb_walk_frags(skb, frag_iter) {
int end;
WARN_ON(start > offset + len);
end = start + frag_iter->len;
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
if (skb_copy_datagram_iovec(frag_iter,
offset - start,
to, copy))
goto fault;
if ((len -= copy) == 0)
return 0;
offset += copy;
}
start = end;
}
/**
* skb_copy_datagram_iter - Copy a datagram to an iovec iterator.
* @skb: buffer to copy
* @offset: offset in the buffer to start copying from
* @to: iovec iterator to copy to
* @len: amount of data to copy from buffer to iovec
*/
int skb_copy_datagram_iter(const struct sk_buff *skb, int offset,
struct iov_iter *to, int len)
{
int start = skb_headlen(skb);
int i, copy = start - offset, start_off = offset, n;
struct sk_buff *frag_iter;
trace_skb_copy_datagram_iovec(skb, len);
/* Copy header. */
if (copy > 0) {
if (copy > len)
copy = len;
n = copy_to_iter(skb->data + offset, copy, to);
offset += n;
if (n != copy)
goto short_copy;
if ((len -= copy) == 0)
return 0;
}
/* Copy paged appendix. Hmm... why does this look so complicated? */
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
int end;
const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
WARN_ON(start > offset + len);
end = start + skb_frag_size(frag);
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
n = copy_page_to_iter(skb_frag_page(frag),
frag->page_offset + offset -
start, copy, to);
offset += n;
if (n != copy)
goto short_copy;
if (!(len -= copy))
return 0;
}
start = end;
}
skb_walk_frags(skb, frag_iter) {
int end;
WARN_ON(start > offset + len);
end = start + frag_iter->len;
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
if (skb_copy_datagram_iter(frag_iter, offset - start,
to, copy))
goto fault;
if ((len -= copy) == 0)
return 0;
offset += copy;
}
start = end;
}
