int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
			const struct sock *sk, const struct request_sock *req,
			const struct sk_buff *skb)
{
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
	const struct tcphdr *th = tcp_hdr(skb);
	__be32 saddr, daddr;

	if (sk) {
		saddr = inet_sk(sk)->inet_saddr;
		daddr = inet_sk(sk)->inet_daddr;
	} else if (req) {
		saddr = inet_rsk(req)->ir_loc_addr;
		daddr = inet_rsk(req)->ir_rmt_addr;
	} else {
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
	}

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;
	desc = &hp->md5_desc;

	if (crypto_hash_init(desc))
		goto clear_hash;

	if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
		goto clear_hash;
	if (tcp_md5_hash_header(hp, th))
		goto clear_hash;
	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
		goto clear_hash;
	if (tcp_md5_hash_key(hp, key))
		goto clear_hash;
	if (crypto_hash_final(desc, md5_hash))
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;

clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
	return 1;
}
int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
			const struct sock *sk, const struct request_sock *req,
			const struct sk_buff *skb)
{
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
	const struct tcphdr *th = tcp_hdr(skb);
	__be32 saddr, daddr;

	if (sk) {
		saddr = inet_sk(sk)->inet_saddr;
		daddr = inet_sk(sk)->inet_daddr;
	} else if (req) {
		saddr = inet_rsk(req)->ir_loc_addr;
		daddr = inet_rsk(req)->ir_rmt_addr;
	} else {
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
	}

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;
	desc = &hp->md5_desc;

	if (crypto_hash_init(desc))
		goto clear_hash;

	if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
		goto clear_hash;
	if (tcp_md5_hash_header(hp, th))
		goto clear_hash;
	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
		goto clear_hash;
	if (tcp_md5_hash_key(hp, key))
		goto clear_hash;
	if (crypto_hash_final(desc, md5_hash))
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;

clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
	return 1;
}