linux/net/x25/x25_forward.c
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   1/*
   2 *      This module:
   3 *              This module is free software; you can redistribute it and/or
   4 *              modify it under the terms of the GNU General Public License
   5 *              as published by the Free Software Foundation; either version
   6 *              2 of the License, or (at your option) any later version.
   7 *
   8 *      History
   9 *      03-01-2007      Added forwarding for x.25       Andrew Hendry
  10 */
  11#include <linux/if_arp.h>
  12#include <linux/init.h>
  13#include <linux/slab.h>
  14#include <net/x25.h>
  15
  16LIST_HEAD(x25_forward_list);
  17DEFINE_RWLOCK(x25_forward_list_lock);
  18
  19int x25_forward_call(struct x25_address *dest_addr, struct x25_neigh *from,
  20                        struct sk_buff *skb, int lci)
  21{
  22        struct x25_route *rt;
  23        struct x25_neigh *neigh_new = NULL;
  24        struct list_head *entry;
  25        struct x25_forward *x25_frwd, *new_frwd;
  26        struct sk_buff *skbn;
  27        short same_lci = 0;
  28        int rc = 0;
  29
  30        if ((rt = x25_get_route(dest_addr)) == NULL)
  31                goto out_no_route;
  32
  33        if ((neigh_new = x25_get_neigh(rt->dev)) == NULL) {
  34                /* This shouldn't happen, if it occurs somehow
  35                 * do something sensible
  36                 */
  37                goto out_put_route;
  38        }
  39
  40        /* Avoid a loop. This is the normal exit path for a
  41         * system with only one x.25 iface and default route
  42         */
  43        if (rt->dev == from->dev) {
  44                goto out_put_nb;
  45        }
  46
  47        /* Remote end sending a call request on an already
  48         * established LCI? It shouldn't happen, just in case..
  49         */
  50        read_lock_bh(&x25_forward_list_lock);
  51        list_for_each(entry, &x25_forward_list) {
  52                x25_frwd = list_entry(entry, struct x25_forward, node);
  53                if (x25_frwd->lci == lci) {
  54                        printk(KERN_WARNING "X.25: call request for lci which is already registered!, transmitting but not registering new pair\n");
  55                        same_lci = 1;
  56                }
  57        }
  58        read_unlock_bh(&x25_forward_list_lock);
  59
  60        /* Save the forwarding details for future traffic */
  61        if (!same_lci){
  62                if ((new_frwd = kmalloc(sizeof(struct x25_forward),
  63                                                GFP_ATOMIC)) == NULL){
  64                        rc = -ENOMEM;
  65                        goto out_put_nb;
  66                }
  67                new_frwd->lci = lci;
  68                new_frwd->dev1 = rt->dev;
  69                new_frwd->dev2 = from->dev;
  70                write_lock_bh(&x25_forward_list_lock);
  71                list_add(&new_frwd->node, &x25_forward_list);
  72                write_unlock_bh(&x25_forward_list_lock);
  73        }
  74
  75        /* Forward the call request */
  76        if ( (skbn = skb_clone(skb, GFP_ATOMIC)) == NULL){
  77                goto out_put_nb;
  78        }
  79        x25_transmit_link(skbn, neigh_new);
  80        rc = 1;
  81
  82
  83out_put_nb:
  84        x25_neigh_put(neigh_new);
  85
  86out_put_route:
  87        x25_route_put(rt);
  88
  89out_no_route:
  90        return rc;
  91}
  92
  93
  94int x25_forward_data(int lci, struct x25_neigh *from, struct sk_buff *skb) {
  95
  96        struct x25_forward *frwd;
  97        struct list_head *entry;
  98        struct net_device *peer = NULL;
  99        struct x25_neigh *nb;
 100        struct sk_buff *skbn;
 101        int rc = 0;
 102
 103        read_lock_bh(&x25_forward_list_lock);
 104        list_for_each(entry, &x25_forward_list) {
 105                frwd = list_entry(entry, struct x25_forward, node);
 106                if (frwd->lci == lci) {
 107                        /* The call is established, either side can send */
 108                        if (from->dev == frwd->dev1) {
 109                                peer = frwd->dev2;
 110                        } else {
 111                                peer = frwd->dev1;
 112                        }
 113                        break;
 114                }
 115        }
 116        read_unlock_bh(&x25_forward_list_lock);
 117
 118        if ( (nb = x25_get_neigh(peer)) == NULL)
 119                goto out;
 120
 121        if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){
 122                goto output;
 123
 124        }
 125        x25_transmit_link(skbn, nb);
 126
 127        rc = 1;
 128output:
 129        x25_neigh_put(nb);
 130out:
 131        return rc;
 132}
 133
 134void x25_clear_forward_by_lci(unsigned int lci)
 135{
 136        struct x25_forward *fwd;
 137        struct list_head *entry, *tmp;
 138
 139        write_lock_bh(&x25_forward_list_lock);
 140
 141        list_for_each_safe(entry, tmp, &x25_forward_list) {
 142                fwd = list_entry(entry, struct x25_forward, node);
 143                if (fwd->lci == lci) {
 144                        list_del(&fwd->node);
 145                        kfree(fwd);
 146                }
 147        }
 148        write_unlock_bh(&x25_forward_list_lock);
 149}
 150
 151
 152void x25_clear_forward_by_dev(struct net_device *dev)
 153{
 154        struct x25_forward *fwd;
 155        struct list_head *entry, *tmp;
 156
 157        write_lock_bh(&x25_forward_list_lock);
 158
 159        list_for_each_safe(entry, tmp, &x25_forward_list) {
 160                fwd = list_entry(entry, struct x25_forward, node);
 161                if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){
 162                        list_del(&fwd->node);
 163                        kfree(fwd);
 164                }
 165        }
 166        write_unlock_bh(&x25_forward_list_lock);
 167}
 168
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