pskb_expand_head (9)

int pskb_expand_head(struct sk_buff * skb, int nhead, int ntail, gfp_t gfp_mask);

skb

buffer to reallocate

nhead

room to add at head

ntail

room to add at tail

gfp_mask

allocation priority

Expands (or creates identical copy, if nhead and ntail are zero) header of skb. sk_buff itself is not changed. sk_buff MUST have reference count of 1. Returns zero in the case of success or error, if expansion failed. In the last case, sk_buff is not changed.

All the pointers pointing into skb header may change and must be reloaded after call to this function.