linux/net/x25/x25_route.c
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   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
  25LIST_HEAD(x25_route_list);
  26DEFINE_RWLOCK(x25_route_list_lock);
  27
  28/*
  29 *      Add a new route.
  30 */
  31static 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;
  62out:
  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 */
  74static 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
  82static 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 */
 109void 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 */
 131struct 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 */
 154struct 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 */
 182int 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);
 208out:
 209        return rc;
 210}
 211
 212/*
 213 *      Release all memory associated with X.25 routing structures.
 214 */
 215void __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}
 227
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