net: add pskb_may_pull_reason() helper

pskb_may_pull() can fail for two different reasons.

Provide pskb_may_pull_reason() helper to distinguish
between these reasons.

It returns:

SKB_NOT_DROPPED_YET           : Success
SKB_DROP_REASON_PKT_TOO_SMALL : packet too small
SKB_DROP_REASON_NOMEM         : skb->head could not be resized

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2023-02-10 18:47:06 +00:00 committed by Jakub Kicinski
parent dc68eaf2c2
commit 1fb2d41501

View file

@ -2631,13 +2631,24 @@ void *skb_pull_data(struct sk_buff *skb, size_t len);
void *__pskb_pull_tail(struct sk_buff *skb, int delta);
static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
static inline enum skb_drop_reason
pskb_may_pull_reason(struct sk_buff *skb, unsigned int len)
{
if (likely(len <= skb_headlen(skb)))
return true;
return SKB_NOT_DROPPED_YET;
if (unlikely(len > skb->len))
return false;
return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
return SKB_DROP_REASON_PKT_TOO_SMALL;
if (unlikely(!__pskb_pull_tail(skb, len - skb_headlen(skb))))
return SKB_DROP_REASON_NOMEM;
return SKB_NOT_DROPPED_YET;
}
static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
{
return pskb_may_pull_reason(skb, len) == SKB_NOT_DROPPED_YET;
}
static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)