net/x25/x25_route.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      X.25 Packet Layer release 002
   4  *
   5  *      This is ALPHA test software. This code may break your machine,
   6  *      randomly fail to work with new releases, misbehave and/or generally
   7  *      screw up. It might even work.
   8  *
   9  *      This code REQUIRES 2.1.15 or higher
  10  *
  11  *      History
  12  *      X.25 001        Jonathan Naylor Started coding.
  13  */
  14
  15 #include <linux/if_arp.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <net/x25.h>
  19
  20 LIST_HEAD(x25_route_list);
  21 DEFINE_RWLOCK(x25_route_list_lock);
  22
  23 /*
  24  *      Add a new route.
  25  */
  26 static int x25_add_route(struct x25_address *address, unsigned int sigdigits,
  27                          struct net_device *dev)
  28 {
  29         struct x25_route *rt;
  30         struct list_head *entry;
  31         int rc = -EINVAL;
  32
  33         write_lock_bh(&x25_route_list_lock);
  34
  35         list_for_each(entry, &x25_route_list) {
  36                 rt = list_entry(entry, struct x25_route, node);
  37
  38                 if (!memcmp(&rt->address, address, sigdigits) &&
  39                     rt->sigdigits == sigdigits)
  40                         goto out;
  41         }
  42
  43         rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
  44         rc = -ENOMEM;
  45         if (!rt)
  46                 goto out;
  47
  48         strcpy(rt->address.x25_addr, "000000000000000");
  49         memcpy(rt->address.x25_addr, address->x25_addr, sigdigits);
  50
  51         rt->sigdigits = sigdigits;
  52         rt->dev       = dev;
  53         refcount_set(&rt->refcnt, 1);
  54
  55         list_add(&rt->node, &x25_route_list);
  56         rc = 0;
  57 out:
  58         write_unlock_bh(&x25_route_list_lock);
  59         return rc;
  60 }
  61
  62 /**
  63  * __x25_remove_route - remove route from x25_route_list
  64  * @rt: route to remove
  65  *
  66  * Remove route from x25_route_list. If it was there.
  67  * Caller must hold x25_route_list_lock.
  68  */
  69 static void __x25_remove_route(struct x25_route *rt)
  70 {
  71         if (rt->node.next) {
  72                 list_del(&rt->node);
  73                 x25_route_put(rt);
  74         }
  75 }
  76
  77 static int x25_del_route(struct x25_address *address, unsigned int sigdigits,
  78                          struct net_device *dev)
  79 {
  80         struct x25_route *rt;
  81         struct list_head *entry;
  82         int rc = -EINVAL;
  83
  84         write_lock_bh(&x25_route_list_lock);
  85
  86         list_for_each(entry, &x25_route_list) {
  87                 rt = list_entry(entry, struct x25_route, node);
  88
  89                 if (!memcmp(&rt->address, address, sigdigits) &&
  90                     rt->sigdigits == sigdigits && rt->dev == dev) {
  91                         __x25_remove_route(rt);
  92                         rc = 0;
  93                         break;
  94                 }
  95         }
  96
  97         write_unlock_bh(&x25_route_list_lock);
  98         return rc;
  99 }
 100
 101 /*
 102  *      A device has been removed, remove its routes.
 103  */
 104 void x25_route_device_down(struct net_device *dev)
 105 {
 106         struct x25_route *rt;
 107         struct list_head *entry, *tmp;
 108
 109         write_lock_bh(&x25_route_list_lock);
 110
 111         list_for_each_safe(entry, tmp, &x25_route_list) {
 112                 rt = list_entry(entry, struct x25_route, node);
 113
 114                 if (rt->dev == dev)
 115                         __x25_remove_route(rt);
 116         }
 117         write_unlock_bh(&x25_route_list_lock);
 118 }
 119
 120 /*
 121  *      Check that the device given is a valid X.25 interface that is "up".
 122  */
 123 struct net_device *x25_dev_get(char *devname)
 124 {
 125         struct net_device *dev = dev_get_by_name(&init_net, devname);
 126
 127         if (dev && (!(dev->flags & IFF_UP) || dev->type != ARPHRD_X25)) {
 128                 dev_put(dev);
 129                 dev = NULL;
 130         }
 131
 132         return dev;
 133 }
 134
 135 /**
 136  *      x25_get_route - Find a route given an X.25 address.
 137  *      @addr: - address to find a route for
 138  *
 139  *      Find a route given an X.25 address.
 140  */
 141 struct x25_route *x25_get_route(struct x25_address *addr)
 142 {
 143         struct x25_route *rt, *use = NULL;
 144         struct list_head *entry;
 145
 146         read_lock_bh(&x25_route_list_lock);
 147
 148         list_for_each(entry, &x25_route_list) {
 149                 rt = list_entry(entry, struct x25_route, node);
 150
 151                 if (!memcmp(&rt->address, addr, rt->sigdigits)) {
 152                         if (!use)
 153                                 use = rt;
 154                         else if (rt->sigdigits > use->sigdigits)
 155                                 use = rt;
 156                 }
 157         }
 158
 159         if (use)
 160                 x25_route_hold(use);
 161
 162         read_unlock_bh(&x25_route_list_lock);
 163         return use;
 164 }
 165
 166 /*
 167  *      Handle the ioctls that control the routing functions.
 168  */
 169 int x25_route_ioctl(unsigned int cmd, void __user *arg)
 170 {
 171         struct x25_route_struct rt;
 172         struct net_device *dev;
 173         int rc = -EINVAL;
 174
 175         if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 176                 goto out;
 177
 178         rc = -EFAULT;
 179         if (copy_from_user(&rt, arg, sizeof(rt)))
 180                 goto out;
 181
 182         rc = -EINVAL;
 183         if (rt.sigdigits > 15)
 184                 goto out;
 185
 186         dev = x25_dev_get(rt.device);
 187         if (!dev)
 188                 goto out;
 189
 190         if (cmd == SIOCADDRT)
 191                 rc = x25_add_route(&rt.address, rt.sigdigits, dev);
 192         else
 193                 rc = x25_del_route(&rt.address, rt.sigdigits, dev);
 194         dev_put(dev);
 195 out:
 196         return rc;
 197 }
 198
 199 /*
 200  *      Release all memory associated with X.25 routing structures.
 201  */
 202 void __exit x25_route_free(void)
 203 {
 204         struct x25_route *rt;
 205         struct list_head *entry, *tmp;
 206
 207         write_lock_bh(&x25_route_list_lock);
 208         list_for_each_safe(entry, tmp, &x25_route_list) {
 209                 rt = list_entry(entry, struct x25_route, node);
 210                 __x25_remove_route(rt);
 211         }
 212         write_unlock_bh(&x25_route_list_lock);
 213 }