x25_forward.c
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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
*/
#define pr_fmt(fmt) "X25: " fmt
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/slab.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 shouldn't 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 shouldn't 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) {
pr_warn("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);
}