root/net/x25/x25_forward.c

DEFINITIONS

1. x25_forward_call
2. x25_forward_data
3. x25_clear_forward_by_lci
4. x25_clear_forward_by_dev

/*
 *      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>

LIST_HEAD(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);
}