/net/ipv4/xfrm4_tunnel.c

  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	=	3,
 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	=	2,
 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);