skb.h

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*  OpenVPN data channel offload
 3 *
 4 *  Copyright (C) 2020-2025 OpenVPN, Inc.
 5 *
 6 *  Author:	Antonio Quartulli <antonio@openvpn.net>
 7 *		James Yonan <james@openvpn.net>
 8 */
 9
10#ifndef _NET_OVPN_SKB_H_
11#define _NET_OVPN_SKB_H_
12
13#include <linux/in.h>
14#include <linux/in6.h>
15#include <linux/ip.h>
16#include <linux/ipv6.h>
17#include <linux/skbuff.h>
18#include <linux/socket.h>
19#include <linux/types.h>
20
21struct ovpn_cb {
22	struct ovpn_peer *peer;
23	struct ovpn_crypto_key_slot *ks;
24	struct aead_request *req;
25	struct scatterlist *sg;
26	u8 *iv;
27	unsigned int payload_offset;
28	bool nosignal;
29};
30
31static inline struct ovpn_cb *ovpn_skb_cb(struct sk_buff *skb)
32{
33	BUILD_BUG_ON(sizeof(struct ovpn_cb) > sizeof(skb->cb));
34	return (struct ovpn_cb *)skb->cb;
35}
36
37/* Return IP protocol version from skb header.
38 * Return 0 if protocol is not IPv4/IPv6 or cannot be read.
39 */
40static inline __be16 ovpn_ip_check_protocol(struct sk_buff *skb)
41{
42	__be16 proto = 0;
43
44	/* skb could be non-linear,
45	 * make sure IP header is in non-fragmented part
46	 */
47	if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
48		return 0;
49
50	if (ip_hdr(skb)->version == 4) {
51		proto = htons(ETH_P_IP);
52	} else if (ip_hdr(skb)->version == 6) {
53		if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
54			return 0;
55		proto = htons(ETH_P_IPV6);
56	}
57
58	return proto;
59}
60
61#endif /* _NET_OVPN_SKB_H_ */