Commit 1fb2d415 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent dc68eaf2

include/linux/skbuff.h

+15 −4
Original line number Diff line number Diff line
@@ -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)