---
name: "skb_cow"
section: "9"
platform: "linux"
package: "linux-manual-4.9"
version: "4.9.228-1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/skb_cow"
---

# skb\_cow(9)

copy header of skb when it is required

## NAME

skb\_cow - copy header of skb when it is required

## SYNOPSIS

**int skb\_cow(struct sk\_buff \*** *skb***, unsigned int** *headroom***);**

## ARGUMENTS

*skb*

buffer to cow

*headroom*

needed headroom

## DESCRIPTION

If the skb passed lacks sufficient headroom or its data part is shared, data is reallocated. If reallocation fails, an error is returned and original skb is not changed.

The result is skb with writable area skb-\>head...skb-\>tail and at least *headroom* of space at head.

## COPYRIGHT