root/net/ipv6/xfrm6_mode_transport.c

DEFINITIONS

1. xfrm6_transport_output
2. xfrm6_transport_input
3. xfrm6_transport_init
4. xfrm6_transport_exit

/*
 * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
 *
 * Copyright (C) 2002 USAGI/WIDE Project
 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/xfrm.h>

/* Add encapsulation header.
 *
 * The IP header and mutable extension headers will be moved forward to make
 * space for the encapsulation header.
 */
static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
{
        struct ipv6hdr *iph;
        u8 *prevhdr;
        int hdr_len;

        iph = ipv6_hdr(skb);

        hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
        skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
        skb_set_network_header(skb, -x->props.header_len);
        skb->transport_header = skb->network_header + hdr_len;
        __skb_pull(skb, hdr_len);
        memmove(ipv6_hdr(skb), iph, hdr_len);
        return 0;
}

/* Remove encapsulation header.
 *
 * The IP header will be moved over the top of the encapsulation header.
 *
 * On entry, skb->h shall point to where the IP header should be and skb->nh
 * shall be set to where the IP header currently is.  skb->data shall point
 * to the start of the payload.
 */
static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
{
        int ihl = skb->data - skb_transport_header(skb);

        if (skb->transport_header != skb->network_header) {
                memmove(skb_transport_header(skb),
                        skb_network_header(skb), ihl);
                skb->network_header = skb->transport_header;
        }
        ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
                                           sizeof(struct ipv6hdr));
        skb_reset_transport_header(skb);
        return 0;
}

static struct xfrm_mode xfrm6_transport_mode = {
        .input = xfrm6_transport_input,
        .output = xfrm6_transport_output,
        .owner = THIS_MODULE,
        .encap = XFRM_MODE_TRANSPORT,
};

static int __init xfrm6_transport_init(void)
{
        return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
}

static void __exit xfrm6_transport_exit(void)
{
        int err;

        err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
        BUG_ON(err);
}

module_init(xfrm6_transport_init);
module_exit(xfrm6_transport_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);