Commit 13244ccc authored by Luiz Augusto von Dentz's avatar Luiz Augusto von Dentz Committed by Marcel Holtmann

skbuff: introduce skb_pull_data

Like skb_pull but returns the original data pointer before pulling the
data after performing a check against sbk->len.

This allows to change code that does "struct foo *p = (void *)skb->data;"
which is hard to audit and error prone, to:

        p = skb_pull_data(skb, sizeof(*p));
        if (!p)
                return;

Which is both safer and cleaner.
Acked-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 561ae1d4
......@@ -2373,6 +2373,8 @@ static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len)
return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len);
}
void *skb_pull_data(struct sk_buff *skb, size_t len);
void *__pskb_pull_tail(struct sk_buff *skb, int delta);
static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len)
......
......@@ -2023,6 +2023,30 @@ void *skb_pull(struct sk_buff *skb, unsigned int len)
}
EXPORT_SYMBOL(skb_pull);
/**
* skb_pull_data - remove data from the start of a buffer returning its
* original position.
* @skb: buffer to use
* @len: amount of data to remove
*
* This function removes data from the start of a buffer, returning
* the memory to the headroom. A pointer to the original data in the buffer
* is returned after checking if there is enough data to pull. Once the
* data has been pulled future pushes will overwrite the old data.
*/
void *skb_pull_data(struct sk_buff *skb, size_t len)
{
void *data = skb->data;
if (skb->len < len)
return NULL;
skb_pull(skb, len);
return data;
}
EXPORT_SYMBOL(skb_pull_data);
/**
* skb_trim - remove end from a buffer
* @skb: buffer to alter
......
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