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 <net/xfrm.h>
12 #include <net/protocol.h>
13
ipip_output(struct xfrm_state * x,struct sk_buff * skb)14 static int ipip_output(struct xfrm_state *x, struct sk_buff *skb)
15 {
16 skb_push(skb, -skb_network_offset(skb));
17 return 0;
18 }
19
ipip_xfrm_rcv(struct xfrm_state * x,struct sk_buff * skb)20 static int ipip_xfrm_rcv(struct xfrm_state *x, struct sk_buff *skb)
21 {
22 return ip_hdr(skb)->protocol;
23 }
24
ipip_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)25 static int ipip_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
26 {
27 if (x->props.mode != XFRM_MODE_TUNNEL) {
28 NL_SET_ERR_MSG(extack, "IPv4 tunnel can only be used with tunnel mode");
29 return -EINVAL;
30 }
31
32 if (x->encap) {
33 NL_SET_ERR_MSG(extack, "IPv4 tunnel is not compatible with encapsulation");
34 return -EINVAL;
35 }
36
37 x->props.header_len = sizeof(struct iphdr);
38
39 return 0;
40 }
41
ipip_destroy(struct xfrm_state * x)42 static void ipip_destroy(struct xfrm_state *x)
43 {
44 }
45
46 static const struct xfrm_type ipip_type = {
47 .owner = THIS_MODULE,
48 .proto = IPPROTO_IPIP,
49 .init_state = ipip_init_state,
50 .destructor = ipip_destroy,
51 .input = ipip_xfrm_rcv,
52 .output = ipip_output
53 };
54
xfrm_tunnel_rcv(struct sk_buff * skb)55 static int xfrm_tunnel_rcv(struct sk_buff *skb)
56 {
57 return xfrm4_rcv_spi(skb, IPPROTO_IPIP, ip_hdr(skb)->saddr);
58 }
59
xfrm_tunnel_err(struct sk_buff * skb,u32 info)60 static int xfrm_tunnel_err(struct sk_buff *skb, u32 info)
61 {
62 return -ENOENT;
63 }
64
65 static struct xfrm_tunnel xfrm_tunnel_handler __read_mostly = {
66 .handler = xfrm_tunnel_rcv,
67 .err_handler = xfrm_tunnel_err,
68 .priority = 4,
69 };
70
71 #if IS_ENABLED(CONFIG_IPV6)
72 static struct xfrm_tunnel xfrm64_tunnel_handler __read_mostly = {
73 .handler = xfrm_tunnel_rcv,
74 .err_handler = xfrm_tunnel_err,
75 .priority = 3,
76 };
77 #endif
78
ipip_init(void)79 static int __init ipip_init(void)
80 {
81 if (xfrm_register_type(&ipip_type, AF_INET) < 0) {
82 pr_info("%s: can't add xfrm type\n", __func__);
83 return -EAGAIN;
84 }
85
86 if (xfrm4_tunnel_register(&xfrm_tunnel_handler, AF_INET)) {
87 pr_info("%s: can't add xfrm handler for AF_INET\n", __func__);
88 xfrm_unregister_type(&ipip_type, AF_INET);
89 return -EAGAIN;
90 }
91 #if IS_ENABLED(CONFIG_IPV6)
92 if (xfrm4_tunnel_register(&xfrm64_tunnel_handler, AF_INET6)) {
93 pr_info("%s: can't add xfrm handler for AF_INET6\n", __func__);
94 xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET);
95 xfrm_unregister_type(&ipip_type, AF_INET);
96 return -EAGAIN;
97 }
98 #endif
99 return 0;
100 }
101
ipip_fini(void)102 static void __exit ipip_fini(void)
103 {
104 #if IS_ENABLED(CONFIG_IPV6)
105 if (xfrm4_tunnel_deregister(&xfrm64_tunnel_handler, AF_INET6))
106 pr_info("%s: can't remove xfrm handler for AF_INET6\n",
107 __func__);
108 #endif
109 if (xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET))
110 pr_info("%s: can't remove xfrm handler for AF_INET\n",
111 __func__);
112 xfrm_unregister_type(&ipip_type, AF_INET);
113 }
114
115 module_init(ipip_init);
116 module_exit(ipip_fini);
117 MODULE_LICENSE("GPL");
118 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_IPIP);
119
