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
 124 /*
 125  *      Check that the device given is a valid X.25 interface that is "up".
 126  */
 127 struct net_device *x25_dev_get(char *devname)
 128 {
 129         struct net_device *dev = dev_get_by_name(devname);
 130
 131         if (dev &&
 132             (!(dev->flags & IFF_UP) || (dev->type != ARPHRD_X25
 133 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
 134                                         && dev->type != ARPHRD_ETHER
 135 #endif
 136                                         )))
 137                 dev_put(dev);
 138
 139         return dev;
 140 }
 141
 142 /**
 143  *      x25_get_route - Find a route given an X.25 address.
 144  *      @addr - address to find a route for
 145  *
 146  *      Find a route given an X.25 address.
 147  */
 148 struct x25_route *x25_get_route(struct x25_address *addr)
 149 {
 150         struct x25_route *rt, *use = NULL;
 151         struct list_head *entry;
 152
 153         read_lock_bh(&x25_route_list_lock);
 154
 155         list_for_each(entry, &x25_route_list) {
 156                 rt = list_entry(entry, struct x25_route, node);
 157
 158                 if (!memcmp(&rt->address, addr, rt->sigdigits)) {
 159                         if (!use)
 160                                 use = rt;
 161                         else if (rt->sigdigits > use->sigdigits)
 162                                 use = rt;
 163                 }
 164         }
 165
 166         if (use)
 167                 x25_route_hold(use);
 168
 169         read_unlock_bh(&x25_route_list_lock);
 170         return use;
 171 }
 172
 173 /*
 174  *      Handle the ioctls that control the routing functions.
 175  */
 176 int x25_route_ioctl(unsigned int cmd, void __user *arg)
 177 {
 178         struct x25_route_struct rt;
 179         struct net_device *dev;
 180         int rc = -EINVAL;
 181
 182         if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 183                 goto out;
 184
 185         rc = -EFAULT;
 186         if (copy_from_user(&rt, arg, sizeof(rt)))
 187                 goto out;
 188
 189         rc = -EINVAL;
 190         if (rt.sigdigits < 0 || rt.sigdigits > 15)
 191                 goto out;
 192
 193         dev = x25_dev_get(rt.device);
 194         if (!dev)
 195                 goto out;
 196
 197         if (cmd == SIOCADDRT)
 198                 rc = x25_add_route(&rt.address, rt.sigdigits, dev);
 199         else
 200                 rc = x25_del_route(&rt.address, rt.sigdigits, dev);
 201         dev_put(dev);
 202 out:
 203         return rc;
 204 }
 205
 206 /*
 207  *      Release all memory associated with X.25 routing structures.
 208  */
 209 void __exit x25_route_free(void)
 210 {
 211         struct x25_route *rt;
 212         struct list_head *entry, *tmp;
 213
 214         write_lock_bh(&x25_route_list_lock);
 215         list_for_each_safe(entry, tmp, &x25_route_list) {
 216                 rt = list_entry(entry, struct x25_route, node);
 217                 __x25_remove_route(rt);
 218         }
 219         write_unlock_bh(&x25_route_list_lock);
 220 }