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