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 <net/x25.h>
  14
  15 struct list_head x25_forward_list = LIST_HEAD_INIT(x25_forward_list);
  16 DEFINE_RWLOCK(x25_forward_list_lock);
  17
  18 int 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
  82 out_put_nb:
  83         x25_neigh_put(neigh_new);
  84
  85 out_put_route:
  86         x25_route_put(rt);
  87
  88 out_no_route:
  89         return rc;
  90 }
  91
  92
  93 int 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;
 127 output:
 128         x25_neigh_put(nb);
 129 out:
 130         return rc;
 131 }
 132
 133 void 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
 151 void 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 }