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 <net/x25.h>
  23
  24 struct list_head x25_route_list = LIST_HEAD_INIT(x25_route_list);
  25 DEFINE_RWLOCK(x25_route_list_lock);
  26
  27 /*
  28  *      Add a new route.
  29  */
  30 static int x25_add_route(struct x25_address *address, unsigned int sigdigits,
  31                          struct net_device *dev)
  32 {
  33         struct x25_route *rt;
  34         struct list_head *entry;
  35         int rc = -EINVAL;
  36
  37         write_lock_bh(&x25_route_list_lock);
  38
  39         list_for_each(entry, &x25_route_list) {
  40                 rt = list_entry(entry, struct x25_route, node);
  41
  42                 if (!memcmp(&rt->address, address, sigdigits) &&
  43                     rt->sigdigits == sigdigits)
  44                         goto out;
  45         }
  46
  47         rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
  48         rc = -ENOMEM;
  49         if (!rt)
  50                 goto out;
  51
  52         strcpy(rt->address.x25_addr, "000000000000000");
  53         memcpy(rt->address.x25_addr, address->x25_addr, sigdigits);
  54
  55         rt->sigdigits = sigdigits;
  56         rt->dev       = dev;
  57         atomic_set(&rt->refcnt, 1);
  58
  59         list_add(&rt->node, &x25_route_list);
  60         rc = 0;
  61 out:
  62         write_unlock_bh(&x25_route_list_lock);
  63         return rc;
  64 }
  65
  66 /**
  67  * __x25_remove_route - remove route from x25_route_list
  68  * @rt - route to remove
  69  *
  70  * Remove route from x25_route_list. If it was there.
  71  * Caller must hold x25_route_list_lock.
  72  */
  73 static void __x25_remove_route(struct x25_route *rt)
  74 {
  75         if (rt->node.next) {
  76                 list_del(&rt->node);
  77                 x25_route_put(rt);
  78         }
  79 }
  80
  81 static int x25_del_route(struct x25_address *address, unsigned int sigdigits,
  82                          struct net_device *dev)
  83 {
  84         struct x25_route *rt;
  85         struct list_head *entry;
  86         int rc = -EINVAL;
  87
  88         write_lock_bh(&x25_route_list_lock);
  89
  90         list_for_each(entry, &x25_route_list) {
  91                 rt = list_entry(entry, struct x25_route, node);
  92
  93                 if (!memcmp(&rt->address, address, sigdigits) &&
  94                     rt->sigdigits == sigdigits && rt->dev == dev) {
  95                         __x25_remove_route(rt);
  96                         rc = 0;
  97                         break;
  98                 }
  99         }
 100
 101         write_unlock_bh(&x25_route_list_lock);
 102         return rc;
 103 }
 104
 105 /*
 106  *      A device has been removed, remove its routes.
 107  */
 108 void x25_route_device_down(struct net_device *dev)
 109 {
 110         struct x25_route *rt;
 111         struct list_head *entry, *tmp;
 112
 113         write_lock_bh(&x25_route_list_lock);
 114
 115         list_for_each_safe(entry, tmp, &x25_route_list) {
 116                 rt = list_entry(entry, struct x25_route, node);
 117
 118                 if (rt->dev == dev)
 119                         __x25_remove_route(rt);
 120         }
 121         write_unlock_bh(&x25_route_list_lock);
 122
 123         /* Remove any related forwarding */
 124         x25_clear_forward_by_dev(dev);
 125 }
 126
 127 /*
 128  *      Check that the device given is a valid X.25 interface that is "up".
 129  */
 130 struct net_device *x25_dev_get(char *devname)
 131 {
 132         struct net_device *dev = dev_get_by_name(&init_net, devname);
 133
 134         if (dev &&
 135             (!(dev->flags & IFF_UP) || (dev->type != ARPHRD_X25
 136 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
 137                                         && dev->type != ARPHRD_ETHER
 138 #endif
 139                                         )))
 140                 dev_put(dev);
 141
 142         return dev;
 143 }
 144
 145 /**
 146  *      x25_get_route - Find a route given an X.25 address.
 147  *      @addr - address to find a route for
 148  *
 149  *      Find a route given an X.25 address.
 150  */
 151 struct x25_route *x25_get_route(struct x25_address *addr)
 152 {
 153         struct x25_route *rt, *use = NULL;
 154         struct list_head *entry;
 155
 156         read_lock_bh(&x25_route_list_lock);
 157
 158         list_for_each(entry, &x25_route_list) {
 159                 rt = list_entry(entry, struct x25_route, node);
 160
 161                 if (!memcmp(&rt->address, addr, rt->sigdigits)) {
 162                         if (!use)
 163                                 use = rt;
 164                         else if (rt->sigdigits > use->sigdigits)
 165                                 use = rt;
 166                 }
 167         }
 168
 169         if (use)
 170                 x25_route_hold(use);
 171
 172         read_unlock_bh(&x25_route_list_lock);
 173         return use;
 174 }
 175
 176 /*
 177  *      Handle the ioctls that control the routing functions.
 178  */
 179 int x25_route_ioctl(unsigned int cmd, void __user *arg)
 180 {
 181         struct x25_route_struct rt;
 182         struct net_device *dev;
 183         int rc = -EINVAL;
 184
 185         if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 186                 goto out;
 187
 188         rc = -EFAULT;
 189         if (copy_from_user(&rt, arg, sizeof(rt)))
 190                 goto out;
 191
 192         rc = -EINVAL;
 193         if (rt.sigdigits < 0 || rt.sigdigits > 15)
 194                 goto out;
 195
 196         dev = x25_dev_get(rt.device);
 197         if (!dev)
 198                 goto out;
 199
 200         if (cmd == SIOCADDRT)
 201                 rc = x25_add_route(&rt.address, rt.sigdigits, dev);
 202         else
 203                 rc = x25_del_route(&rt.address, rt.sigdigits, dev);
 204         dev_put(dev);
 205 out:
 206         return rc;
 207 }
 208
 209 /*
 210  *      Release all memory associated with X.25 routing structures.
 211  */
 212 void __exit x25_route_free(void)
 213 {
 214         struct x25_route *rt;
 215         struct list_head *entry, *tmp;
 216
 217         write_lock_bh(&x25_route_list_lock);
 218         list_for_each_safe(entry, tmp, &x25_route_list) {
 219                 rt = list_entry(entry, struct x25_route, node);
 220                 __x25_remove_route(rt);
 221         }
 222         write_unlock_bh(&x25_route_list_lock);
 223 }