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         int rc = -EINVAL;
  31
  32         write_lock_bh(&x25_route_list_lock);
  33
  34         list_for_each_entry(rt, &x25_route_list, node) {
  35                 if (!memcmp(&rt->address, address, sigdigits) &&
  36                     rt->sigdigits == sigdigits)
  37                         goto out;
  38         }
  39
  40         rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
  41         rc = -ENOMEM;
  42         if (!rt)
  43                 goto out;
  44
  45         strcpy(rt->address.x25_addr, "000000000000000");
  46         memcpy(rt->address.x25_addr, address->x25_addr, sigdigits);
  47
  48         rt->sigdigits = sigdigits;
  49         rt->dev       = dev;
  50         refcount_set(&rt->refcnt, 1);
  51
  52         list_add(&rt->node, &x25_route_list);
  53         rc = 0;
  54 out:
  55         write_unlock_bh(&x25_route_list_lock);
  56         return rc;
  57 }
  58
  59 /**
  60  * __x25_remove_route - remove route from x25_route_list
  61  * @rt: route to remove
  62  *
  63  * Remove route from x25_route_list. If it was there.
  64  * Caller must hold x25_route_list_lock.
  65  */
  66 static void __x25_remove_route(struct x25_route *rt)
  67 {
  68         if (rt->node.next) {
  69                 list_del(&rt->node);
  70                 x25_route_put(rt);
  71         }
  72 }
  73
  74 static int x25_del_route(struct x25_address *address, unsigned int sigdigits,
  75                          struct net_device *dev)
  76 {
  77         struct x25_route *rt;
  78         int rc = -EINVAL;
  79
  80         write_lock_bh(&x25_route_list_lock);
  81
  82         list_for_each_entry(rt, &x25_route_list, node) {
  83                 if (!memcmp(&rt->address, address, sigdigits) &&
  84                     rt->sigdigits == sigdigits && rt->dev == dev) {
  85                         __x25_remove_route(rt);
  86                         rc = 0;
  87                         break;
  88                 }
  89         }
  90
  91         write_unlock_bh(&x25_route_list_lock);
  92         return rc;
  93 }
  94
  95 /*
  96  *      A device has been removed, remove its routes.
  97  */
  98 void x25_route_device_down(struct net_device *dev)
  99 {
 100         struct x25_route *rt;
 101         struct list_head *entry, *tmp;
 102
 103         write_lock_bh(&x25_route_list_lock);
 104
 105         list_for_each_safe(entry, tmp, &x25_route_list) {
 106                 rt = list_entry(entry, struct x25_route, node);
 107
 108                 if (rt->dev == dev)
 109                         __x25_remove_route(rt);
 110         }
 111         write_unlock_bh(&x25_route_list_lock);
 112 }
 113
 114 /*
 115  *      Check that the device given is a valid X.25 interface that is "up".
 116  */
 117 struct net_device *x25_dev_get(char *devname)
 118 {
 119         struct net_device *dev = dev_get_by_name(&init_net, devname);
 120
 121         if (dev && (!(dev->flags & IFF_UP) || dev->type != ARPHRD_X25)) {
 122                 dev_put(dev);
 123                 dev = NULL;
 124         }
 125
 126         return dev;
 127 }
 128
 129 /**
 130  *      x25_get_route - Find a route given an X.25 address.
 131  *      @addr: - address to find a route for
 132  *
 133  *      Find a route given an X.25 address.
 134  */
 135 struct x25_route *x25_get_route(struct x25_address *addr)
 136 {
 137         struct x25_route *rt, *use = NULL;
 138
 139         read_lock_bh(&x25_route_list_lock);
 140
 141         list_for_each_entry(rt, &x25_route_list, node) {
 142                 if (!memcmp(&rt->address, addr, rt->sigdigits)) {
 143                         if (!use)
 144                                 use = rt;
 145                         else if (rt->sigdigits > use->sigdigits)
 146                                 use = rt;
 147                 }
 148         }
 149
 150         if (use)
 151                 x25_route_hold(use);
 152
 153         read_unlock_bh(&x25_route_list_lock);
 154         return use;
 155 }
 156
 157 /*
 158  *      Handle the ioctls that control the routing functions.
 159  */
 160 int x25_route_ioctl(unsigned int cmd, void __user *arg)
 161 {
 162         struct x25_route_struct rt;
 163         struct net_device *dev;
 164         int rc = -EINVAL;
 165
 166         if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 167                 goto out;
 168
 169         rc = -EFAULT;
 170         if (copy_from_user(&rt, arg, sizeof(rt)))
 171                 goto out;
 172
 173         rc = -EINVAL;
 174         if (rt.sigdigits > 15)
 175                 goto out;
 176
 177         dev = x25_dev_get(rt.device);
 178         if (!dev)
 179                 goto out;
 180
 181         if (cmd == SIOCADDRT)
 182                 rc = x25_add_route(&rt.address, rt.sigdigits, dev);
 183         else
 184                 rc = x25_del_route(&rt.address, rt.sigdigits, dev);
 185         dev_put(dev);
 186 out:
 187         return rc;
 188 }
 189
 190 /*
 191  *      Release all memory associated with X.25 routing structures.
 192  */
 193 void __exit x25_route_free(void)
 194 {
 195         struct x25_route *rt;
 196         struct list_head *entry, *tmp;
 197
 198         write_lock_bh(&x25_route_list_lock);
 199         list_for_each_safe(entry, tmp, &x25_route_list) {
 200                 rt = list_entry(entry, struct x25_route, node);
 201                 __x25_remove_route(rt);
 202         }
 203         write_unlock_bh(&x25_route_list_lock);
 204 }