| 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); |