net/phonet/pn_dev.c

   1 /*
   2  * File: pn_dev.c
   3  *
   4  * Phonet network device
   5  *
   6  * Copyright (C) 2008 Nokia Corporation.
   7  *
   8  * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
   9  * Original author: Sakari Ailus <sakari.ailus@nokia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * version 2 as published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  23  * 02110-1301 USA
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/net.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/phonet.h>
  30 #include <net/sock.h>
  31 #include <net/netns/generic.h>
  32 #include <net/phonet/pn_dev.h>
  33
  34 struct phonet_net {
  35         struct phonet_device_list pndevs;
  36 };
  37
  38 int phonet_net_id;
  39
  40 struct phonet_device_list *phonet_device_list(struct net *net)
  41 {
  42         struct phonet_net *pnn = net_generic(net, phonet_net_id);
  43         return &pnn->pndevs;
  44 }
  45
  46 /* Allocate new Phonet device. */
  47 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
  48 {
  49         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  50         struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
  51         if (pnd == NULL)
  52                 return NULL;
  53         pnd->netdev = dev;
  54         bitmap_zero(pnd->addrs, 64);
  55
  56         list_add(&pnd->list, &pndevs->list);
  57         return pnd;
  58 }
  59
  60 static struct phonet_device *__phonet_get(struct net_device *dev)
  61 {
  62         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  63         struct phonet_device *pnd;
  64
  65         list_for_each_entry(pnd, &pndevs->list, list) {
  66                 if (pnd->netdev == dev)
  67                         return pnd;
  68         }
  69         return NULL;
  70 }
  71
  72 static void __phonet_device_free(struct phonet_device *pnd)
  73 {
  74         list_del(&pnd->list);
  75         kfree(pnd);
  76 }
  77
  78 struct net_device *phonet_device_get(struct net *net)
  79 {
  80         struct phonet_device_list *pndevs = phonet_device_list(net);
  81         struct phonet_device *pnd;
  82         struct net_device *dev;
  83
  84         spin_lock_bh(&pndevs->lock);
  85         list_for_each_entry(pnd, &pndevs->list, list) {
  86                 dev = pnd->netdev;
  87                 BUG_ON(!dev);
  88
  89                 if ((dev->reg_state == NETREG_REGISTERED) &&
  90                         ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
  91                         break;
  92                 dev = NULL;
  93         }
  94         if (dev)
  95                 dev_hold(dev);
  96         spin_unlock_bh(&pndevs->lock);
  97         return dev;
  98 }
  99
 100 int phonet_address_add(struct net_device *dev, u8 addr)
 101 {
 102         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 103         struct phonet_device *pnd;
 104         int err = 0;
 105
 106         spin_lock_bh(&pndevs->lock);
 107         /* Find or create Phonet-specific device data */
 108         pnd = __phonet_get(dev);
 109         if (pnd == NULL)
 110                 pnd = __phonet_device_alloc(dev);
 111         if (unlikely(pnd == NULL))
 112                 err = -ENOMEM;
 113         else if (test_and_set_bit(addr >> 2, pnd->addrs))
 114                 err = -EEXIST;
 115         spin_unlock_bh(&pndevs->lock);
 116         return err;
 117 }
 118
 119 int phonet_address_del(struct net_device *dev, u8 addr)
 120 {
 121         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 122         struct phonet_device *pnd;
 123         int err = 0;
 124
 125         spin_lock_bh(&pndevs->lock);
 126         pnd = __phonet_get(dev);
 127         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs))
 128                 err = -EADDRNOTAVAIL;
 129         else if (bitmap_empty(pnd->addrs, 64))
 130                 __phonet_device_free(pnd);
 131         spin_unlock_bh(&pndevs->lock);
 132         return err;
 133 }
 134
 135 /* Gets a source address toward a destination, through a interface. */
 136 u8 phonet_address_get(struct net_device *dev, u8 addr)
 137 {
 138         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 139         struct phonet_device *pnd;
 140
 141         spin_lock_bh(&pndevs->lock);
 142         pnd = __phonet_get(dev);
 143         if (pnd) {
 144                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 145
 146                 /* Use same source address as destination, if possible */
 147                 if (!test_bit(addr >> 2, pnd->addrs))
 148                         addr = find_first_bit(pnd->addrs, 64) << 2;
 149         } else
 150                 addr = PN_NO_ADDR;
 151         spin_unlock_bh(&pndevs->lock);
 152         return addr;
 153 }
 154
 155 int phonet_address_lookup(struct net *net, u8 addr)
 156 {
 157         struct phonet_device_list *pndevs = phonet_device_list(net);
 158         struct phonet_device *pnd;
 159         int err = -EADDRNOTAVAIL;
 160
 161         spin_lock_bh(&pndevs->lock);
 162         list_for_each_entry(pnd, &pndevs->list, list) {
 163                 /* Don't allow unregistering devices! */
 164                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 165                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 166                         continue;
 167
 168                 if (test_bit(addr >> 2, pnd->addrs)) {
 169                         err = 0;
 170                         goto found;
 171                 }
 172         }
 173 found:
 174         spin_unlock_bh(&pndevs->lock);
 175         return err;
 176 }
 177
 178 /* notify Phonet of device events */
 179 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 180                                 void *arg)
 181 {
 182         struct net_device *dev = arg;
 183
 184         if (what == NETDEV_UNREGISTER) {
 185                 struct phonet_device_list *pndevs;
 186                 struct phonet_device *pnd;
 187
 188                 /* Destroy phonet-specific device data */
 189                 pndevs = phonet_device_list(dev_net(dev));
 190                 spin_lock_bh(&pndevs->lock);
 191                 pnd = __phonet_get(dev);
 192                 if (pnd)
 193                         __phonet_device_free(pnd);
 194                 spin_unlock_bh(&pndevs->lock);
 195         }
 196         return 0;
 197
 198 }
 199
 200 static struct notifier_block phonet_device_notifier = {
 201         .notifier_call = phonet_device_notify,
 202         .priority = 0,
 203 };
 204
 205 /* Per-namespace Phonet devices handling */
 206 static int phonet_init_net(struct net *net)
 207 {
 208         struct phonet_net *pnn = kmalloc(sizeof(*pnn), GFP_KERNEL);
 209         if (!pnn)
 210                 return -ENOMEM;
 211
 212         INIT_LIST_HEAD(&pnn->pndevs.list);
 213         spin_lock_init(&pnn->pndevs.lock);
 214         net_assign_generic(net, phonet_net_id, pnn);
 215         return 0;
 216 }
 217
 218 static void phonet_exit_net(struct net *net)
 219 {
 220         struct phonet_net *pnn = net_generic(net, phonet_net_id);
 221         struct phonet_device *pnd, *n;
 222
 223         list_for_each_entry_safe(pnd, n, &pnn->pndevs.list, list)
 224                 __phonet_device_free(pnd);
 225
 226         kfree(pnn);
 227 }
 228
 229 static struct pernet_operations phonet_net_ops = {
 230         .init = phonet_init_net,
 231         .exit = phonet_exit_net,
 232 };
 233
 234 /* Initialize Phonet devices list */
 235 int __init phonet_device_init(void)
 236 {
 237         int err = register_pernet_gen_device(&phonet_net_id, &phonet_net_ops);
 238         if (err)
 239                 return err;
 240
 241         register_netdevice_notifier(&phonet_device_notifier);
 242         err = phonet_netlink_register();
 243         if (err)
 244                 phonet_device_exit();
 245         return err;
 246 }
 247
 248 void phonet_device_exit(void)
 249 {
 250         rtnl_unregister_all(PF_PHONET);
 251         unregister_netdevice_notifier(&phonet_device_notifier);
 252         unregister_pernet_gen_device(phonet_net_id, &phonet_net_ops);
 253 }