From: Eric Dumazet <[email protected]> [ Upstream commit 1fb2d41501f38192d8a19da585cd441cf8845697 ]
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 <[email protected]> Reviewed-by: David Ahern <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]> Stable-dep-of: 8bd67ebb50c0 ("net: bridge: xmit: make sure we have at least eth header len bytes") Signed-off-by: Sasha Levin <[email protected]> [Sherry: bp to 5.15.y. Minor conflicts due to missing commit d427c8999b07 ("net-next: skbuff: refactor pskb_pull") which is not necessary in 5.15.y. Ignore context change. Signed-off-by: Sherry Yang <[email protected]> --- include/linux/skbuff.h | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index b230c422dc3b..f92e8fe4f5eb 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2465,13 +2465,24 @@ static inline void *pskb_pull(struct sk_buff *skb, unsigned int len) return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len); } -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; } void skb_condense(struct sk_buff *skb); -- 2.46.0
