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
  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
  22 static int ipip_xfrm_rcv(struct xfrm_state *x, struct sk_buff *skb)
  23 {
  24         return ip_hdr(skb)->protocol;
  25 }
  26
  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
  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
  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
  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
  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
 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);