root/net/ipv6/xfrm6_mode_beet.c

DEFINITIONS

1. xfrm6_beet_make_header
2. xfrm6_beet_output
3. xfrm6_beet_input
4. xfrm6_beet_init
5. xfrm6_beet_exit

/*
 * xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
 *
 * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
 *                    Miika Komu     <miika@iki.fi>
 *                    Herbert Xu     <herbert@gondor.apana.org.au>
 *                    Abhinav Pathak <abhinav.pathak@hiit.fi>
 *                    Jeff Ahrenholz <ahrenholz@gmail.com>
 */

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

static void xfrm6_beet_make_header(struct sk_buff *skb)
{
        struct ipv6hdr *iph = ipv6_hdr(skb);

        iph->version = 6;

        memcpy(iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
               sizeof(iph->flow_lbl));
        iph->nexthdr = XFRM_MODE_SKB_CB(skb)->protocol;

        ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
        iph->hop_limit = XFRM_MODE_SKB_CB(skb)->ttl;
}

/* Add encapsulation header.
 *
 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
 */
static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
{
        struct ipv6hdr *top_iph;
        struct ip_beet_phdr *ph;
        struct iphdr *iphv4;
        int optlen, hdr_len;

        iphv4 = ip_hdr(skb);
        hdr_len = 0;
        optlen = XFRM_MODE_SKB_CB(skb)->optlen;
        if (unlikely(optlen))
                hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);

        skb_set_network_header(skb, -x->props.header_len - hdr_len);
        if (x->sel.family != AF_INET6)
                skb->network_header += IPV4_BEET_PHMAXLEN;
        skb->mac_header = skb->network_header +
                          offsetof(struct ipv6hdr, nexthdr);
        skb->transport_header = skb->network_header + sizeof(*top_iph);
        ph = (struct ip_beet_phdr *)__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl-hdr_len);

        xfrm6_beet_make_header(skb);

        top_iph = ipv6_hdr(skb);
        if (unlikely(optlen)) {

                BUG_ON(optlen < 0);

                ph->padlen = 4 - (optlen & 4);
                ph->hdrlen = optlen / 8;
                ph->nexthdr = top_iph->nexthdr;
                if (ph->padlen)
                        memset(ph + 1, IPOPT_NOP, ph->padlen);

                top_iph->nexthdr = IPPROTO_BEETPH;
        }

        ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
        ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
        return 0;
}

static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
{
        struct ipv6hdr *ip6h;
        const unsigned char *old_mac;
        int size = sizeof(struct ipv6hdr);
        int err;

        err = skb_cow_head(skb, size + skb->mac_len);
        if (err)
                goto out;

        __skb_push(skb, size);
        skb_reset_network_header(skb);

        old_mac = skb_mac_header(skb);
        skb_set_mac_header(skb, -skb->mac_len);
        memmove(skb_mac_header(skb), old_mac, skb->mac_len);

        xfrm6_beet_make_header(skb);

        ip6h = ipv6_hdr(skb);
        ip6h->payload_len = htons(skb->len - size);
        ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
        ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
        err = 0;
out:
        return err;
}

static struct xfrm_mode xfrm6_beet_mode = {
        .input2 = xfrm6_beet_input,
        .input = xfrm_prepare_input,
        .output2 = xfrm6_beet_output,
        .output = xfrm6_prepare_output,
        .owner = THIS_MODULE,
        .encap = XFRM_MODE_BEET,
        .flags = XFRM_MODE_FLAG_TUNNEL,
};

static int __init xfrm6_beet_init(void)
{
        return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
}

static void __exit xfrm6_beet_exit(void)
{
        int err;

        err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
        BUG_ON(err);
}

module_init(xfrm6_beet_init);
module_exit(xfrm6_beet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);