Quelle  x25_forward.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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 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_frwd, &x25_forward_list, 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 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(frwd, &x25_forward_list, 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, *tmp;

 write_lock_bh(&x25_forward_list_lock);

 list_for_each_entry_safe(fwd, tmp, &x25_forward_list, 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, *tmp;

 write_lock_bh(&x25_forward_list_lock);

 list_for_each_entry_safe(fwd, tmp, &x25_forward_list, node) {
  if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){
   list_del(&fwd->node);
   kfree(fwd);
  }
 }
 write_unlock_bh(&x25_forward_list_lock);
}