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