1// SPDX-License-Identifier: GPL-2.0-only
2/* xfrm4_tunnel.c: Generic IP tunnel transformer.
3 *
4 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
5 */
6
7#define pr_fmt(fmt) "IPsec: " fmt
8
9#include <linux/skbuff.h>
10#include <linux/module.h>
11#include <linux/mutex.h>
12#include <net/xfrm.h>
13#include <net/ip.h>
14#include <net/protocol.h>
15
16static int ipip_output(struct xfrm_state *x, struct sk_buff *skb)
17{
18	skb_push(skb, -skb_network_offset(skb));
19	return 0;
20}
21
22static int ipip_xfrm_rcv(struct xfrm_state *x, struct sk_buff *skb)
23{
24	return ip_hdr(skb)->protocol;
25}
26
27static int ipip_init_state(struct xfrm_state *x)
28{
29	if (x->props.mode != XFRM_MODE_TUNNEL)
30		return -EINVAL;
31
32	if (x->encap)
33		return -EINVAL;
34
35	x->props.header_len = sizeof(struct iphdr);
36
37	return 0;
38}
39
40static void ipip_destroy(struct xfrm_state *x)
41{
42}
43
44static const struct xfrm_type ipip_type = {
45	.description	= "IPIP",
46	.owner		= THIS_MODULE,
47	.proto	     	= IPPROTO_IPIP,
48	.init_state	= ipip_init_state,
49	.destructor	= ipip_destroy,
50	.input		= ipip_xfrm_rcv,
51	.output		= ipip_output
52};
53
54static int xfrm_tunnel_rcv(struct sk_buff *skb)
55{
56	return xfrm4_rcv_spi(skb, IPPROTO_IPIP, ip_hdr(skb)->saddr);
57}
58
59static int xfrm_tunnel_err(struct sk_buff *skb, u32 info)
60{
61	return -ENOENT;
62}
63
64static struct xfrm_tunnel xfrm_tunnel_handler __read_mostly = {
65	.handler	=	xfrm_tunnel_rcv,
66	.err_handler	=	xfrm_tunnel_err,
67	.priority	=	4,
68};
69
70#if IS_ENABLED(CONFIG_IPV6)
71static struct xfrm_tunnel xfrm64_tunnel_handler __read_mostly = {
72	.handler	=	xfrm_tunnel_rcv,
73	.err_handler	=	xfrm_tunnel_err,
74	.priority	=	3,
75};
76#endif
77
78static int __init ipip_init(void)
79{
80	if (xfrm_register_type(&ipip_type, AF_INET) < 0) {
81		pr_info("%s: can't add xfrm type\n", __func__);
82		return -EAGAIN;
83	}
84
85	if (xfrm4_tunnel_register(&xfrm_tunnel_handler, AF_INET)) {
86		pr_info("%s: can't add xfrm handler for AF_INET\n", __func__);
87		xfrm_unregister_type(&ipip_type, AF_INET);
88		return -EAGAIN;
89	}
90#if IS_ENABLED(CONFIG_IPV6)
91	if (xfrm4_tunnel_register(&xfrm64_tunnel_handler, AF_INET6)) {
92		pr_info("%s: can't add xfrm handler for AF_INET6\n", __func__);
93		xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET);
94		xfrm_unregister_type(&ipip_type, AF_INET);
95		return -EAGAIN;
96	}
97#endif
98	return 0;
99}
100
101static void __exit ipip_fini(void)
102{
103#if IS_ENABLED(CONFIG_IPV6)
104	if (xfrm4_tunnel_deregister(&xfrm64_tunnel_handler, AF_INET6))
105		pr_info("%s: can't remove xfrm handler for AF_INET6\n",
106			__func__);
107#endif
108	if (xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET))
109		pr_info("%s: can't remove xfrm handler for AF_INET\n",
110			__func__);
111	xfrm_unregister_type(&ipip_type, AF_INET);
112}
113
114module_init(ipip_init);
115module_exit(ipip_fini);
116MODULE_LICENSE("GPL");
117MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_IPIP);
118