Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.

 *

 * 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/dst.h>

#include <net/ip.h>

#include <net/xfrm.h>

/* Add encapsulation header.

 *

 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.

 */

static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)

{

        struct ip_beet_phdr *ph;

        struct iphdr *iph, *top_iph;

        int hdrlen, optlen;

        iph = ip_hdr(skb);

        hdrlen = 0;

        optlen = iph->ihl * 4 - sizeof(*iph);

        if (unlikely(optlen))

                hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);

        skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -

                                    hdrlen);

        skb->mac_header = skb->network_header +

                          offsetof(struct iphdr, protocol);

        skb->transport_header = skb->network_header + sizeof(*iph);

        ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);

        top_iph = ip_hdr(skb);

        memmove(top_iph, iph, sizeof(*iph));

        if (unlikely(optlen)) {

                BUG_ON(optlen < 0);

                ph->padlen = 4 - (optlen & 4);

                ph->hdrlen = optlen / 8;

                ph->nexthdr = top_iph->protocol;

                if (ph->padlen)

                        memset(ph + 1, IPOPT_NOP, ph->padlen);

                top_iph->protocol = IPPROTO_BEETPH;

                top_iph->ihl = sizeof(struct iphdr) / 4;

        }

        top_iph->saddr = x->props.saddr.a4;

        top_iph->daddr = x->id.daddr.a4;

        return 0;

}

static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)

{

        struct iphdr *iph = ip_hdr(skb);

        int phlen = 0;

        int optlen = 0;

        u8 ph_nexthdr = 0;

        int err = -EINVAL;

        if (unlikely(iph->protocol == IPPROTO_BEETPH)) {

                struct ip_beet_phdr *ph;

                if (!pskb_may_pull(skb, sizeof(*ph)))

                        goto out;

                ph = (struct ip_beet_phdr *)(ipip_hdr(skb) + 1);

                phlen = sizeof(*ph) + ph->padlen;

                optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);

                if (optlen < 0 || optlen & 3 || optlen > 250)

                        goto out;

                if (!pskb_may_pull(skb, phlen + optlen))

                        goto out;

                skb->len -= phlen + optlen;

                ph_nexthdr = ph->nexthdr;

        }

        skb_set_network_header(skb, phlen - sizeof(*iph));

        memmove(skb_network_header(skb), iph, sizeof(*iph));

        skb_set_transport_header(skb, phlen + optlen);

        skb->data = skb_transport_header(skb);

        iph = ip_hdr(skb);

        iph->ihl = (sizeof(*iph) + optlen) / 4;

        iph->tot_len = htons(skb->len + iph->ihl * 4);

        iph->daddr = x->sel.daddr.a4;

        iph->saddr = x->sel.saddr.a4;

        if (ph_nexthdr)

                iph->protocol = ph_nexthdr;

        iph->check = 0;

        iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);

        err = 0;

out:

        return err;

}

static struct xfrm_mode xfrm4_beet_mode = {

        .input = xfrm4_beet_input,

        .output = xfrm4_beet_output,

        .owner = THIS_MODULE,

        .encap = XFRM_MODE_BEET,

        .flags = XFRM_MODE_FLAG_TUNNEL,

};

static int __init xfrm4_beet_init(void)

{

        return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);

}

static void __exit xfrm4_beet_exit(void)

{

        int err;

        err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);

        BUG_ON(err);

}

module_init(xfrm4_beet_init);

module_exit(xfrm4_beet_exit);

MODULE_LICENSE("GPL");

MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);