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
  12 #define pr_fmt(fmt) "X25: " fmt
  13
  14 #include <linux/if_arp.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <net/x25.h>
  18
  19 LIST_HEAD(x25_forward_list);
  20 DEFINE_RWLOCK(x25_forward_list_lock);
  21
  22 int x25_forward_call(struct x25_address *dest_addr, struct x25_neigh *from,
  23                         struct sk_buff *skb, int lci)
  24 {
  25         struct x25_route *rt;
  26         struct x25_neigh *neigh_new = NULL;
  27         struct list_head *entry;
  28         struct x25_forward *x25_frwd, *new_frwd;
  29         struct sk_buff *skbn;
  30         short same_lci = 0;
  31         int rc = 0;
  32
  33         if ((rt = x25_get_route(dest_addr)) == NULL)
  34                 goto out_no_route;
  35
  36         if ((neigh_new = x25_get_neigh(rt->dev)) == NULL) {
  37                 /* This shouldn't happen, if it occurs somehow
  38                  * do something sensible
  39                  */
  40                 goto out_put_route;
  41         }
  42
  43         /* Avoid a loop. This is the normal exit path for a
  44          * system with only one x.25 iface and default route
  45          */
  46         if (rt->dev == from->dev) {
  47                 goto out_put_nb;
  48         }
  49
  50         /* Remote end sending a call request on an already
  51          * established LCI? It shouldn't happen, just in case..
  52          */
  53         read_lock_bh(&x25_forward_list_lock);
  54         list_for_each(entry, &x25_forward_list) {
  55                 x25_frwd = list_entry(entry, struct x25_forward, node);
  56                 if (x25_frwd->lci == lci) {
  57                         pr_warn("call request for lci which is already registered!, transmitting but not registering new pair\n");
  58                         same_lci = 1;
  59                 }
  60         }
  61         read_unlock_bh(&x25_forward_list_lock);
  62
  63         /* Save the forwarding details for future traffic */
  64         if (!same_lci){
  65                 if ((new_frwd = kmalloc(sizeof(struct x25_forward),
  66                                                 GFP_ATOMIC)) == NULL){
  67                         rc = -ENOMEM;
  68                         goto out_put_nb;
  69                 }
  70                 new_frwd->lci = lci;
  71                 new_frwd->dev1 = rt->dev;
  72                 new_frwd->dev2 = from->dev;
  73                 write_lock_bh(&x25_forward_list_lock);
  74                 list_add(&new_frwd->node, &x25_forward_list);
  75                 write_unlock_bh(&x25_forward_list_lock);
  76         }
  77
  78         /* Forward the call request */
  79         if ( (skbn = skb_clone(skb, GFP_ATOMIC)) == NULL){
  80                 goto out_put_nb;
  81         }
  82         x25_transmit_link(skbn, neigh_new);
  83         rc = 1;
  84
  85
  86 out_put_nb:
  87         x25_neigh_put(neigh_new);
  88
  89 out_put_route:
  90         x25_route_put(rt);
  91
  92 out_no_route:
  93         return rc;
  94 }
  95
  96
  97 int x25_forward_data(int lci, struct x25_neigh *from, struct sk_buff *skb) {
  98
  99         struct x25_forward *frwd;
 100         struct list_head *entry;
 101         struct net_device *peer = NULL;
 102         struct x25_neigh *nb;
 103         struct sk_buff *skbn;
 104         int rc = 0;
 105
 106         read_lock_bh(&x25_forward_list_lock);
 107         list_for_each(entry, &x25_forward_list) {
 108                 frwd = list_entry(entry, struct x25_forward, node);
 109                 if (frwd->lci == lci) {
 110                         /* The call is established, either side can send */
 111                         if (from->dev == frwd->dev1) {
 112                                 peer = frwd->dev2;
 113                         } else {
 114                                 peer = frwd->dev1;
 115                         }
 116                         break;
 117                 }
 118         }
 119         read_unlock_bh(&x25_forward_list_lock);
 120
 121         if ( (nb = x25_get_neigh(peer)) == NULL)
 122                 goto out;
 123
 124         if ( (skbn = pskb_copy(skb, GFP_ATOMIC)) == NULL){
 125                 goto output;
 126
 127         }
 128         x25_transmit_link(skbn, nb);
 129
 130         rc = 1;
 131 output:
 132         x25_neigh_put(nb);
 133 out:
 134         return rc;
 135 }
 136
 137 void x25_clear_forward_by_lci(unsigned int lci)
 138 {
 139         struct x25_forward *fwd;
 140         struct list_head *entry, *tmp;
 141
 142         write_lock_bh(&x25_forward_list_lock);
 143
 144         list_for_each_safe(entry, tmp, &x25_forward_list) {
 145                 fwd = list_entry(entry, struct x25_forward, node);
 146                 if (fwd->lci == lci) {
 147                         list_del(&fwd->node);
 148                         kfree(fwd);
 149                 }
 150         }
 151         write_unlock_bh(&x25_forward_list_lock);
 152 }
 153
 154
 155 void x25_clear_forward_by_dev(struct net_device *dev)
 156 {
 157         struct x25_forward *fwd;
 158         struct list_head *entry, *tmp;
 159
 160         write_lock_bh(&x25_forward_list_lock);
 161
 162         list_for_each_safe(entry, tmp, &x25_forward_list) {
 163                 fwd = list_entry(entry, struct x25_forward, node);
 164                 if ((fwd->dev1 == dev) || (fwd->dev2 == dev)){
 165                         list_del(&fwd->node);
 166                         kfree(fwd);
 167                 }
 168         }
 169         write_unlock_bh(&x25_forward_list_lock);
 170 }