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/*

 *      This module:

 *              This module is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 *

 *      History

 *      03-01-2007      Added forwarding for x.25       Andrew Hendry

 */

#include <linux/if_arp.h>

#include <linux/init.h>

#include <net/x25.h>

struct list_head x25_forward_list = LIST_HEAD_INIT(x25_forward_list);

DEFINE_RWLOCK(x25_forward_list_lock);

int x25_forward_call(struct x25_address *dest_addr, struct x25_neigh *from,

                        struct sk_buff *skb, int lci)

{

        struct x25_route *rt;

        struct x25_neigh *neigh_new = NULL;

        struct list_head *entry;

        struct x25_forward *x25_frwd, *new_frwd;

        struct sk_buff *skbn;

        short same_lci = 0;

        int rc = 0;

        if ((rt = x25_get_route(dest_addr)) == NULL)

                goto out_no_route;

        if ((neigh_new = x25_get_neigh(rt->dev)) == NULL) {

                /* This shouldnt happen, if it occurs somehow

                 * do something sensible

                 */

                goto out_put_route;

        }

        /* Avoid a loop. This is the normal exit path for a

         * system with only one x.25 iface and default route

         */

        if (rt->dev == from->dev) {

                goto out_put_nb;

        }

        /* Remote end sending a call request on an already

         * established LCI? It shouldnt happen, just in case..

         */

        read_lock_bh(&x25_forward_list_lock);

        list_for_each(entry, &x25_forward_list) {

                x25_frwd = list_entry(entry, struct x25_forward, node);

                if (x25_frwd->lci == lci) {

                        printk(KERN_WARNING "X.25: call request for lci which is already registered!, transmitting but not registering new pair\n");

                        same_lci = 1;

                }

        }

        read_unlock_bh(&x25_forward_list_lock);

        /* Save the forwarding details for future traffic */

        if (!same_lci){

                if ((new_frwd = kmalloc(sizeof(struct x25_forward),

                                                GFP_ATOMIC)) == NULL){

                        rc = -ENOMEM;

                        goto out_put_nb;

                }

                new_frwd->lci = lci;

                new_frwd->dev1 = rt->dev;

                new_frwd->dev2 = from->dev;

                write_lock_bh(&x25_forward_list_lock);

                list_add(&new_frwd->node, &x25_forward_list);

                write_unlock_bh(&x25_forward_list_lock);

        }

        /* Forward the call request */

        if ( (skbn = skb_clone(skb, GFP_ATOMIC)) == NULL){

                goto out_put_nb;

        }

        x25_transmit_link(skbn, neigh_new);

        rc = 1;

out_put_nb:

        x25_neigh_put(neigh_new);

out_put_route:

        x25_route_put(rt);

out_no_route:

        return rc;

}

int x25_forward_data(int lci, struct x25_neigh *from, struct sk_buff *skb) {

        struct x25_forward *frwd;

        struct list_head *entry;

        struct net_device *peer = NULL;

        struct x25_neigh *nb;

        struct sk_buff *skbn;

        int rc = 0;

        read_lock_bh(&x25_forward_list_lock);

        list_for_each(entry, &x25_forward_list) {

                frwd = list_entry(entry, struct x25_forward, node);

                if (frwd->lci == lci) {

                        /* The call is established, either side can send */

                        if (from->dev == frwd->dev1) {

                                peer = frwd->dev2;

                        } else {

                                peer = frwd->dev1;

                        }

                        break;

                }

        }

        read_unlock_bh(&x25_forward_list_lock);

        if ( (nb = x25_get_neigh(peer)) == NULL)

                goto out;

        if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){

                goto output;

        }

        x25_transmit_link(skbn, nb);

        rc = 1;

output:

        x25_neigh_put(nb);

out:

        return rc;

}

void x25_clear_forward_by_lci(unsigned int lci)

{

        struct x25_forward *fwd;

        struct list_head *entry, *tmp;

        write_lock_bh(&x25_forward_list_lock);

        list_for_each_safe(entry, tmp, &x25_forward_list) {

                fwd = list_entry(entry, struct x25_forward, node);

                if (fwd->lci == lci) {

                        list_del(&fwd->node);

                        kfree(fwd);

                }

        }

        write_unlock_bh(&x25_forward_list_lock);

}

void x25_clear_forward_by_dev(struct net_device *dev)

{

        struct x25_forward *fwd;

        struct list_head *entry, *tmp;

        write_lock_bh(&x25_forward_list_lock);

        list_for_each_safe(entry, tmp, &x25_forward_list) {

                fwd = list_entry(entry, struct x25_forward, node);

                if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){

                        list_del(&fwd->node);

                        kfree(fwd);

                }

        }

        write_unlock_bh(&x25_forward_list_lock);

}