#ifndef _NET_AH_H#define _NET_AH_H #include <linux/crypto.h>#include <net/xfrm.h> /* This is the maximum truncated ICV length that we know of. */#define MAX_AH_AUTH_LEN	12 struct ah_data{	u8			*key;	int			key_len;	u8			*work_icv;	int			icv_full_len;	int			icv_trunc_len; 	struct crypto_hash	*tfm;}; static inline int ah_mac_digest(struct ah_data *ahp, struct sk_buff *skb,				u8 *auth_data){	struct hash_desc desc;	int err; 	desc.tfm = ahp->tfm;	desc.flags = 0; 	memset(auth_data, 0, ahp->icv_trunc_len);	err = crypto_hash_init(&desc);	if (unlikely(err))		goto out;	err = skb_icv_walk(skb, &desc, 0, skb->len, crypto_hash_update);	if (unlikely(err))		goto out;	err = crypto_hash_final(&desc, ahp->work_icv); out:	return err;} #endif