net/x25/x25_forward.c

   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
  16 LIST_HEAD(x25_forward_list);
  17 DEFINE_RWLOCK(x25_forward_list_lock);
  18
  19 int 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
  83 out_put_nb:
  84         x25_neigh_put(neigh_new);
  85
  86 out_put_route:
  87         x25_route_put(rt);
  88
  89 out_no_route:
  90         return rc;
  91 }
  92
  93
  94 int 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;
 128 output:
 129         x25_neigh_put(nb);
 130 out:
 131         return rc;
 132 }
 133
 134 void 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
 152 void 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 }