net/x25/x25_route.c

   1 /*
   2  *      X.25 Packet Layer release 002
   3  *
   4  *      This is ALPHA test software. This code may break your machine,
   5  *      randomly fail to work with new releases, misbehave and/or generally
   6  *      screw up. It might even work.
   7  *
   8  *      This code REQUIRES 2.1.15 or higher
   9  *
  10  *      This module:
  11  *              This module is free software; you can redistribute it and/or
  12  *              modify it under the terms of the GNU General Public License
  13  *              as published by the Free Software Foundation; either version
  14  *              2 of the License, or (at your option) any later version.
  15  *
  16  *      History
  17  *      X.25 001        Jonathan Naylor Started coding.
  18  */
  19
  20 #include <linux/if_arp.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <net/x25.h>
  24
  25 LIST_HEAD(x25_route_list);
  26 DEFINE_RWLOCK(x25_route_list_lock);
  27
  28 /*
  29  *      Add a new route.
  30  */
  31 static int x25_add_route(struct x25_address *address, unsigned int sigdigits,
  32                          struct net_device *dev)
  33 {
  34         struct x25_route *rt;
  35         struct list_head *entry;
  36         int rc = -EINVAL;
  37
  38         write_lock_bh(&x25_route_list_lock);
  39
  40         list_for_each(entry, &x25_route_list) {
  41                 rt = list_entry(entry, struct x25_route, node);
  42
  43                 if (!memcmp(&rt->address, address, sigdigits) &&
  44                     rt->sigdigits == sigdigits)
  45                         goto out;
  46         }
  47
  48         rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
  49         rc = -ENOMEM;
  50         if (!rt)
  51                 goto out;
  52
  53         strcpy(rt->address.x25_addr, "000000000000000");
  54         memcpy(rt->address.x25_addr, address->x25_addr, sigdigits);
  55
  56         rt->sigdigits = sigdigits;
  57         rt->dev       = dev;
  58         atomic_set(&rt->refcnt, 1);
  59
  60         list_add(&rt->node, &x25_route_list);
  61         rc = 0;
  62 out:
  63         write_unlock_bh(&x25_route_list_lock);
  64         return rc;
  65 }
  66
  67 /**
  68  * __x25_remove_route - remove route from x25_route_list
  69  * @rt - route to remove
  70  *
  71  * Remove route from x25_route_list. If it was there.
  72  * Caller must hold x25_route_list_lock.
  73  */
  74 static void __x25_remove_route(struct x25_route *rt)
  75 {
  76         if (rt->node.next) {
  77                 list_del(&rt->node);
  78                 x25_route_put(rt);
  79         }
  80 }
  81
  82 static int x25_del_route(struct x25_address *address, unsigned int sigdigits,
  83                          struct net_device *dev)
  84 {
  85         struct x25_route *rt;
  86         struct list_head *entry;
  87         int rc = -EINVAL;
  88
  89         write_lock_bh(&x25_route_list_lock);
  90
  91         list_for_each(entry, &x25_route_list) {
  92                 rt = list_entry(entry, struct x25_route, node);
  93
  94                 if (!memcmp(&rt->address, address, sigdigits) &&
  95                     rt->sigdigits == sigdigits && rt->dev == dev) {
  96                         __x25_remove_route(rt);
  97                         rc = 0;
  98                         break;
  99                 }
 100         }
 101
 102         write_unlock_bh(&x25_route_list_lock);
 103         return rc;
 104 }
 105
 106 /*
 107  *      A device has been removed, remove its routes.
 108  */
 109 void x25_route_device_down(struct net_device *dev)
 110 {
 111         struct x25_route *rt;
 112         struct list_head *entry, *tmp;
 113
 114         write_lock_bh(&x25_route_list_lock);
 115
 116         list_for_each_safe(entry, tmp, &x25_route_list) {
 117                 rt = list_entry(entry, struct x25_route, node);
 118
 119                 if (rt->dev == dev)
 120                         __x25_remove_route(rt);
 121         }
 122         write_unlock_bh(&x25_route_list_lock);
 123
 124         /* Remove any related forwarding */
 125         x25_clear_forward_by_dev(dev);
 126 }
 127
 128 /*
 129  *      Check that the device given is a valid X.25 interface that is "up".
 130  */
 131 struct net_device *x25_dev_get(char *devname)
 132 {
 133         struct net_device *dev = dev_get_by_name(&init_net, devname);
 134
 135         if (dev &&
 136             (!(dev->flags & IFF_UP) || (dev->type != ARPHRD_X25
 137 #if IS_ENABLED(CONFIG_LLC)
 138                                         && dev->type != ARPHRD_ETHER
 139 #endif
 140                                         ))){
 141                 dev_put(dev);
 142                 dev = NULL;
 143         }
 144
 145         return dev;
 146 }
 147
 148 /**
 149  *      x25_get_route - Find a route given an X.25 address.
 150  *      @addr - address to find a route for
 151  *
 152  *      Find a route given an X.25 address.
 153  */
 154 struct x25_route *x25_get_route(struct x25_address *addr)
 155 {
 156         struct x25_route *rt, *use = NULL;
 157         struct list_head *entry;
 158
 159         read_lock_bh(&x25_route_list_lock);
 160
 161         list_for_each(entry, &x25_route_list) {
 162                 rt = list_entry(entry, struct x25_route, node);
 163
 164                 if (!memcmp(&rt->address, addr, rt->sigdigits)) {
 165                         if (!use)
 166                                 use = rt;
 167                         else if (rt->sigdigits > use->sigdigits)
 168                                 use = rt;
 169                 }
 170         }
 171
 172         if (use)
 173                 x25_route_hold(use);
 174
 175         read_unlock_bh(&x25_route_list_lock);
 176         return use;
 177 }
 178
 179 /*
 180  *      Handle the ioctls that control the routing functions.
 181  */
 182 int x25_route_ioctl(unsigned int cmd, void __user *arg)
 183 {
 184         struct x25_route_struct rt;
 185         struct net_device *dev;
 186         int rc = -EINVAL;
 187
 188         if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 189                 goto out;
 190
 191         rc = -EFAULT;
 192         if (copy_from_user(&rt, arg, sizeof(rt)))
 193                 goto out;
 194
 195         rc = -EINVAL;
 196         if (rt.sigdigits > 15)
 197                 goto out;
 198
 199         dev = x25_dev_get(rt.device);
 200         if (!dev)
 201                 goto out;
 202
 203         if (cmd == SIOCADDRT)
 204                 rc = x25_add_route(&rt.address, rt.sigdigits, dev);
 205         else
 206                 rc = x25_del_route(&rt.address, rt.sigdigits, dev);
 207         dev_put(dev);
 208 out:
 209         return rc;
 210 }
 211
 212 /*
 213  *      Release all memory associated with X.25 routing structures.
 214  */
 215 void __exit x25_route_free(void)
 216 {
 217         struct x25_route *rt;
 218         struct list_head *entry, *tmp;
 219
 220         write_lock_bh(&x25_route_list_lock);
 221         list_for_each_safe(entry, tmp, &x25_route_list) {
 222                 rt = list_entry(entry, struct x25_route, node);
 223                 __x25_remove_route(rt);
 224         }
 225         write_unlock_bh(&x25_route_list_lock);
 226 }