xfrm4_tunnel.c

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/* xfrm4_tunnel.c: Generic IP tunnel transformer.
 *
 * Copyright (C) 2003 David S. Miller ([email protected])
 */

#define pr_fmt(fmt) "IPsec: " fmt

#include <linux/skbuff.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/protocol.h>

static int ipip_output(struct xfrm_state *x, struct sk_buff *skb)
{
    skb_push(skb, -skb_network_offset(skb));
    return 0;
}

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

static int ipip_init_state(struct xfrm_state *x)
{
    if (x->props.mode != XFRM_MODE_TUNNEL)
        return -EINVAL;

    if (x->encap)
        return -EINVAL;

    x->props.header_len = sizeof(struct iphdr);

    return 0;
}

static void ipip_destroy(struct xfrm_state *x)
{
}

static const struct xfrm_type ipip_type = {
    .description    = "IPIP",
    .owner      = THIS_MODULE,
    .proto          = IPPROTO_IPIP,
    .init_state = ipip_init_state,
    .destructor = ipip_destroy,
    .input      = ipip_xfrm_rcv,
    .output     = ipip_output
};

static int xfrm_tunnel_rcv(struct sk_buff *skb)
{
    return xfrm4_rcv_spi(skb, IPPROTO_IPIP, ip_hdr(skb)->saddr);
}

static int xfrm_tunnel_err(struct sk_buff *skb, u32 info)
{
    return -ENOENT;
}

static struct xfrm_tunnel xfrm_tunnel_handler __read_mostly = {
    .handler    =   xfrm_tunnel_rcv,
    .err_handler    =   xfrm_tunnel_err,
    .priority   =   2,
};

#if IS_ENABLED(CONFIG_IPV6)
static struct xfrm_tunnel xfrm64_tunnel_handler __read_mostly = {
    .handler    =   xfrm_tunnel_rcv,
    .err_handler    =   xfrm_tunnel_err,
    .priority   =   2,
};
#endif

static int __init ipip_init(void)
{
    if (xfrm_register_type(&ipip_type, AF_INET) < 0) {
        pr_info("%s: can't add xfrm type\n", __func__);
        return -EAGAIN;
    }

    if (xfrm4_tunnel_register(&xfrm_tunnel_handler, AF_INET)) {
        pr_info("%s: can't add xfrm handler for AF_INET\n", __func__);
        xfrm_unregister_type(&ipip_type, AF_INET);
        return -EAGAIN;
    }
#if IS_ENABLED(CONFIG_IPV6)
    if (xfrm4_tunnel_register(&xfrm64_tunnel_handler, AF_INET6)) {
        pr_info("%s: can't add xfrm handler for AF_INET6\n", __func__);
        xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET);
        xfrm_unregister_type(&ipip_type, AF_INET);
        return -EAGAIN;
    }
#endif
    return 0;
}

static void __exit ipip_fini(void)
{
#if IS_ENABLED(CONFIG_IPV6)
    if (xfrm4_tunnel_deregister(&xfrm64_tunnel_handler, AF_INET6))
        pr_info("%s: can't remove xfrm handler for AF_INET6\n",
            __func__);
#endif
    if (xfrm4_tunnel_deregister(&xfrm_tunnel_handler, AF_INET))
        pr_info("%s: can't remove xfrm handler for AF_INET\n",
            __func__);
    if (xfrm_unregister_type(&ipip_type, AF_INET) < 0)
        pr_info("%s: can't remove xfrm type\n", __func__);
}

module_init(ipip_init);
module_exit(ipip_fini);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_IPIP);