Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.

 *

 * 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/inet_ecn.h>

#include <net/ip.h>

#include <net/xfrm.h>

static inline void ipip_ecn_decapsulate(struct sk_buff *skb)

{

        struct iphdr *outer_iph = ip_hdr(skb);

        struct iphdr *inner_iph = ipip_hdr(skb);

        if (INET_ECN_is_ce(outer_iph->tos))

                IP_ECN_set_ce(inner_iph);

}

static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)

{

        if (INET_ECN_is_ce(iph->tos))

                IP6_ECN_set_ce(ipv6_hdr(skb));

}

/* Add encapsulation header.

 *

 * The top IP header will be constructed per RFC 2401.

 */

static int xfrm4_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)

{

        struct dst_entry *dst = skb->dst;

        struct xfrm_dst *xdst = (struct xfrm_dst*)dst;

        struct iphdr *iph, *top_iph;

        int flags;

        iph = ip_hdr(skb);

        skb_set_network_header(skb, -x->props.header_len);

        skb->mac_header = skb->network_header +

                          offsetof(struct iphdr, protocol);

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

        top_iph = ip_hdr(skb);

        top_iph->ihl = 5;

        top_iph->version = 4;

        flags = x->props.flags;

        /* DS disclosed */

        if (xdst->route->ops->family == AF_INET) {

                top_iph->protocol = IPPROTO_IPIP;

                top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);

                top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?

        }

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)

        else {

                struct ipv6hdr *ipv6h = (struct ipv6hdr*)iph;

                top_iph->protocol = IPPROTO_IPV6;

                top_iph->tos = INET_ECN_encapsulate(iph->tos, ipv6_get_dsfield(ipv6h));

                top_iph->frag_off = 0;

        }

#endif

        if (flags & XFRM_STATE_NOECN)

                IP_ECN_clear(top_iph);

        if (!top_iph->frag_off)

                __ip_select_ident(top_iph, dst->child, 0);

        top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);

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

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

        skb->protocol = htons(ETH_P_IP);

        memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));

        return 0;

}

static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)

{

        struct iphdr *iph = ip_hdr(skb);

        const unsigned char *old_mac;

        int err = -EINVAL;

        switch (iph->protocol){

                case IPPROTO_IPIP:

                        break;

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)

                case IPPROTO_IPV6:

                        break;

#endif

                default:

                        goto out;

        }

        if (!pskb_may_pull(skb, sizeof(struct iphdr)))

                goto out;

        if (skb_cloned(skb) &&

            (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))

                goto out;

        iph = ip_hdr(skb);

        if (iph->protocol == IPPROTO_IPIP) {

                if (x->props.flags & XFRM_STATE_DECAP_DSCP)

                        ipv4_copy_dscp(iph, ipip_hdr(skb));

                if (!(x->props.flags & XFRM_STATE_NOECN))

                        ipip_ecn_decapsulate(skb);

        }

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)

        else {

                if (!(x->props.flags & XFRM_STATE_NOECN))

                        ipip6_ecn_decapsulate(iph, skb);

                skb->protocol = htons(ETH_P_IPV6);

        }

#endif

        old_mac = skb_mac_header(skb);

        skb_set_mac_header(skb, -skb->mac_len);

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

        skb_reset_network_header(skb);

        err = 0;

out:

        return err;

}

static struct xfrm_mode xfrm4_tunnel_mode = {

        .input = xfrm4_tunnel_input,

        .output = xfrm4_tunnel_output,

        .owner = THIS_MODULE,

        .encap = XFRM_MODE_TUNNEL,

        .flags = XFRM_MODE_FLAG_TUNNEL,

};

static int __init xfrm4_tunnel_init(void)

{

        return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);

}

static void __exit xfrm4_tunnel_exit(void)

{

        int err;

        err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);

        BUG_ON(err);

}

module_init(xfrm4_tunnel_init);

module_exit(xfrm4_tunnel_exit);

MODULE_LICENSE("GPL");

MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);