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
ipip_output(struct xfrm_state * x,struct sk_buff * skb)16 static 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
ipip_xfrm_rcv(struct xfrm_state * x,struct sk_buff * skb)22 static int ipip_xfrm_rcv(struct xfrm_state *x, struct sk_buff *skb)
23 {
24 return ip_hdr(skb)->protocol;
25 }
26
ipip_init_state(struct xfrm_state * x)27 static 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
ipip_destroy(struct xfrm_state * x)40 static void ipip_destroy(struct xfrm_state *x)
41 {
42 }
43
44 static 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
xfrm_tunnel_rcv(struct sk_buff * skb)54 static int xfrm_tunnel_rcv(struct sk_buff *skb)
55 {
56 return xfrm4_rcv_spi(skb, IPPROTO_IPIP, ip_hdr(skb)->saddr);
57 }
58
xfrm_tunnel_err(struct sk_buff * skb,u32 info)59 static int xfrm_tunnel_err(struct sk_buff *skb, u32 info)
60 {
61 return -ENOENT;
62 }
63
64 static 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)
71 static 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
ipip_init(void)78 static 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
ipip_fini(void)101 static 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
114 module_init(ipip_init);
115 module_exit(ipip_fini);
116 MODULE_LICENSE("GPL");
117 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_IPIP);
118
