LXR linux/net/x25/x25

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