*
* The `hlen` as calculated by skb_zerocopy_headlen() specifies the
* headroom in the `to` buffer.
+ *
+ * Return value:
+ * 0: everything is OK
+ * -ENOMEM: couldn't orphan frags of @from due to lack of memory
+ * -EFAULT: skb_copy_bits() found some problem with skb geometry
*/
-void
-skb_zerocopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
+int
+skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
{
int i, j = 0;
int plen = 0; /* length of skb->head fragment */
+ int ret;
struct page *page;
unsigned int offset;
BUG_ON(!from->head_frag && !hlen);
/* dont bother with small payloads */
- if (len <= skb_tailroom(to)) {
- skb_copy_bits(from, 0, skb_put(to, len), len);
- return;
- }
+ if (len <= skb_tailroom(to))
+ return skb_copy_bits(from, 0, skb_put(to, len), len);
if (hlen) {
- skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+ ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
+ if (unlikely(ret))
+ return ret;
len -= hlen;
} else {
plen = min_t(int, skb_headlen(from), len);
to->len += len + plen;
to->data_len += len + plen;
+ if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
+ skb_tx_error(from);
+ return -ENOMEM;
+ }
+
for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
if (!len)
break;
j++;
}
skb_shinfo(to)->nr_frags = j;
+
+ return 0;
}
EXPORT_SYMBOL_GPL(skb_zerocopy);
/**
* skb_segment - Perform protocol segmentation on skb.
- * @skb: buffer to segment
+ * @head_skb: buffer to segment
* @features: features for the output path (see dev->features)
*
* This function performs segmentation on the given skb. It returns
* a pointer to the first in a list of new skbs for the segments.
* In case of error it returns ERR_PTR(err).
*/
-struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
+struct sk_buff *skb_segment(struct sk_buff *head_skb,
+ netdev_features_t features)
{
struct sk_buff *segs = NULL;
struct sk_buff *tail = NULL;
- struct sk_buff *fskb = skb_shinfo(skb)->frag_list;
- skb_frag_t *skb_frag = skb_shinfo(skb)->frags;
- unsigned int mss = skb_shinfo(skb)->gso_size;
- unsigned int doffset = skb->data - skb_mac_header(skb);
+ struct sk_buff *list_skb = skb_shinfo(head_skb)->frag_list;
+ skb_frag_t *frag = skb_shinfo(head_skb)->frags;
+ unsigned int mss = skb_shinfo(head_skb)->gso_size;
+ unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
+ struct sk_buff *frag_skb = head_skb;
unsigned int offset = doffset;
- unsigned int tnl_hlen = skb_tnl_header_len(skb);
+ unsigned int tnl_hlen = skb_tnl_header_len(head_skb);
unsigned int headroom;
unsigned int len;
__be16 proto;
bool csum;
int sg = !!(features & NETIF_F_SG);
- int nfrags = skb_shinfo(skb)->nr_frags;
+ int nfrags = skb_shinfo(head_skb)->nr_frags;
int err = -ENOMEM;
int i = 0;
int pos;
+ int dummy;
- proto = skb_network_protocol(skb);
+ proto = skb_network_protocol(head_skb, &dummy);
if (unlikely(!proto))
return ERR_PTR(-EINVAL);
csum = !!can_checksum_protocol(features, proto);
- __skb_push(skb, doffset);
- headroom = skb_headroom(skb);
- pos = skb_headlen(skb);
+ __skb_push(head_skb, doffset);
+ headroom = skb_headroom(head_skb);
+ pos = skb_headlen(head_skb);
do {
struct sk_buff *nskb;
- skb_frag_t *frag;
+ skb_frag_t *nskb_frag;
int hsize;
int size;
- len = skb->len - offset;
+ len = head_skb->len - offset;
if (len > mss)
len = mss;
- hsize = skb_headlen(skb) - offset;
+ hsize = skb_headlen(head_skb) - offset;
if (hsize < 0)
hsize = 0;
if (hsize > len || !sg)
hsize = len;
- if (!hsize && i >= nfrags && skb_headlen(fskb) &&
- (skb_headlen(fskb) == len || sg)) {
- BUG_ON(skb_headlen(fskb) > len);
+ if (!hsize && i >= nfrags && skb_headlen(list_skb) &&
+ (skb_headlen(list_skb) == len || sg)) {
+ BUG_ON(skb_headlen(list_skb) > len);
i = 0;
- nfrags = skb_shinfo(fskb)->nr_frags;
- skb_frag = skb_shinfo(fskb)->frags;
- pos += skb_headlen(fskb);
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
+ pos += skb_headlen(list_skb);
while (pos < offset + len) {
BUG_ON(i >= nfrags);
- size = skb_frag_size(skb_frag);
+ size = skb_frag_size(frag);
if (pos + size > offset + len)
break;
i++;
pos += size;
- skb_frag++;
+ frag++;
}
- nskb = skb_clone(fskb, GFP_ATOMIC);
- fskb = fskb->next;
+ nskb = skb_clone(list_skb, GFP_ATOMIC);
+ list_skb = list_skb->next;
if (unlikely(!nskb))
goto err;
__skb_push(nskb, doffset);
} else {
nskb = __alloc_skb(hsize + doffset + headroom,
- GFP_ATOMIC, skb_alloc_rx_flag(skb),
+ GFP_ATOMIC, skb_alloc_rx_flag(head_skb),
NUMA_NO_NODE);
if (unlikely(!nskb))
segs = nskb;
tail = nskb;
- __copy_skb_header(nskb, skb);
- nskb->mac_len = skb->mac_len;
+ __copy_skb_header(nskb, head_skb);
+ nskb->mac_len = head_skb->mac_len;
skb_headers_offset_update(nskb, skb_headroom(nskb) - headroom);
- skb_copy_from_linear_data_offset(skb, -tnl_hlen,
+ skb_copy_from_linear_data_offset(head_skb, -tnl_hlen,
nskb->data - tnl_hlen,
doffset + tnl_hlen);
if (!sg) {
nskb->ip_summed = CHECKSUM_NONE;
- nskb->csum = skb_copy_and_csum_bits(skb, offset,
+ nskb->csum = skb_copy_and_csum_bits(head_skb, offset,
skb_put(nskb, len),
len, 0);
continue;
}
- frag = skb_shinfo(nskb)->frags;
+ nskb_frag = skb_shinfo(nskb)->frags;
- skb_copy_from_linear_data_offset(skb, offset,
+ skb_copy_from_linear_data_offset(head_skb, offset,
skb_put(nskb, hsize), hsize);
- skb_shinfo(nskb)->tx_flags = skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
+ skb_shinfo(nskb)->tx_flags = skb_shinfo(head_skb)->tx_flags &
+ SKBTX_SHARED_FRAG;
while (pos < offset + len) {
if (i >= nfrags) {
- BUG_ON(skb_headlen(fskb));
+ BUG_ON(skb_headlen(list_skb));
i = 0;
- nfrags = skb_shinfo(fskb)->nr_frags;
- skb_frag = skb_shinfo(fskb)->frags;
+ nfrags = skb_shinfo(list_skb)->nr_frags;
+ frag = skb_shinfo(list_skb)->frags;
+ frag_skb = list_skb;
BUG_ON(!nfrags);
- fskb = fskb->next;
+ list_skb = list_skb->next;
}
if (unlikely(skb_shinfo(nskb)->nr_frags >=
goto err;
}
- *frag = *skb_frag;
- __skb_frag_ref(frag);
- size = skb_frag_size(frag);
+ if (unlikely(skb_orphan_frags(frag_skb, GFP_ATOMIC)))
+ goto err;
+
+ *nskb_frag = *frag;
+ __skb_frag_ref(nskb_frag);
+ size = skb_frag_size(nskb_frag);
if (pos < offset) {
- frag->page_offset += offset - pos;
- skb_frag_size_sub(frag, offset - pos);
+ nskb_frag->page_offset += offset - pos;
+ skb_frag_size_sub(nskb_frag, offset - pos);
}
skb_shinfo(nskb)->nr_frags++;
if (pos + size <= offset + len) {
i++;
- skb_frag++;
+ frag++;
pos += size;
} else {
- skb_frag_size_sub(frag, pos + size - (offset + len));
+ skb_frag_size_sub(nskb_frag, pos + size - (offset + len));
goto skip_fraglist;
}
- frag++;
+ nskb_frag++;
}
skip_fraglist:
nskb->len - doffset, 0);
nskb->ip_summed = CHECKSUM_NONE;
}
- } while ((offset += len) < skb->len);
+ } while ((offset += len) < head_skb->len);
return segs;
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