net: skb_condense() can also deal with empty skbs
It seems attackers can also send UDP packets with no payload at all. skb_condense() can still be a win in this case. It will be possible to replace the custom code in tcp_add_backlog() to get full benefit from skb_condense() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
5ac9efbe1c
commit
3174fed982
|
@ -4946,16 +4946,20 @@ EXPORT_SYMBOL(pskb_extract);
|
|||
*/
|
||||
void skb_condense(struct sk_buff *skb)
|
||||
{
|
||||
if (!skb->data_len ||
|
||||
skb->data_len > skb->end - skb->tail ||
|
||||
skb_cloned(skb))
|
||||
return;
|
||||
if (skb->data_len) {
|
||||
if (skb->data_len > skb->end - skb->tail ||
|
||||
skb_cloned(skb))
|
||||
return;
|
||||
|
||||
/* Nice, we can free page frag(s) right now */
|
||||
__pskb_pull_tail(skb, skb->data_len);
|
||||
|
||||
/* Now adjust skb->truesize, since __pskb_pull_tail() does
|
||||
* not do this.
|
||||
/* Nice, we can free page frag(s) right now */
|
||||
__pskb_pull_tail(skb, skb->data_len);
|
||||
}
|
||||
/* At this point, skb->truesize might be over estimated,
|
||||
* because skb had a fragment, and fragments do not tell
|
||||
* their truesize.
|
||||
* When we pulled its content into skb->head, fragment
|
||||
* was freed, but __pskb_pull_tail() could not possibly
|
||||
* adjust skb->truesize, not knowing the frag truesize.
|
||||
*/
|
||||
skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue