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 <linux/proc_fs.h>
  31 #include <net/sock.h>
  32 #include <net/netns/generic.h>
  33 #include <net/phonet/pn_dev.h>
  34
  35 struct phonet_net {
  36         struct phonet_device_list pndevs;
  37 };
  38
  39 int phonet_net_id;
  40
  41 struct phonet_device_list *phonet_device_list(struct net *net)
  42 {
  43         struct phonet_net *pnn = net_generic(net, phonet_net_id);
  44         return &pnn->pndevs;
  45 }
  46
  47 /* Allocate new Phonet device. */
  48 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
  49 {
  50         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  51         struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
  52         if (pnd == NULL)
  53                 return NULL;
  54         pnd->netdev = dev;
  55         bitmap_zero(pnd->addrs, 64);
  56
  57         list_add(&pnd->list, &pndevs->list);
  58         return pnd;
  59 }
  60
  61 static struct phonet_device *__phonet_get(struct net_device *dev)
  62 {
  63         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  64         struct phonet_device *pnd;
  65
  66         list_for_each_entry(pnd, &pndevs->list, list) {
  67                 if (pnd->netdev == dev)
  68                         return pnd;
  69         }
  70         return NULL;
  71 }
  72
  73 static void phonet_device_destroy(struct net_device *dev)
  74 {
  75         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  76         struct phonet_device *pnd;
  77
  78         ASSERT_RTNL();
  79
  80         spin_lock_bh(&pndevs->lock);
  81         pnd = __phonet_get(dev);
  82         if (pnd)
  83                 list_del(&pnd->list);
  84         spin_unlock_bh(&pndevs->lock);
  85
  86         if (pnd) {
  87                 u8 addr;
  88
  89                 for (addr = find_first_bit(pnd->addrs, 64); addr < 64;
  90                         addr = find_next_bit(pnd->addrs, 64, 1+addr))
  91                         phonet_address_notify(RTM_DELADDR, dev, addr);
  92                 kfree(pnd);
  93         }
  94 }
  95
  96 struct net_device *phonet_device_get(struct net *net)
  97 {
  98         struct phonet_device_list *pndevs = phonet_device_list(net);
  99         struct phonet_device *pnd;
 100         struct net_device *dev;
 101
 102         spin_lock_bh(&pndevs->lock);
 103         list_for_each_entry(pnd, &pndevs->list, list) {
 104                 dev = pnd->netdev;
 105                 BUG_ON(!dev);
 106
 107                 if ((dev->reg_state == NETREG_REGISTERED) &&
 108                         ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
 109                         break;
 110                 dev = NULL;
 111         }
 112         if (dev)
 113                 dev_hold(dev);
 114         spin_unlock_bh(&pndevs->lock);
 115         return dev;
 116 }
 117
 118 int phonet_address_add(struct net_device *dev, u8 addr)
 119 {
 120         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 121         struct phonet_device *pnd;
 122         int err = 0;
 123
 124         spin_lock_bh(&pndevs->lock);
 125         /* Find or create Phonet-specific device data */
 126         pnd = __phonet_get(dev);
 127         if (pnd == NULL)
 128                 pnd = __phonet_device_alloc(dev);
 129         if (unlikely(pnd == NULL))
 130                 err = -ENOMEM;
 131         else if (test_and_set_bit(addr >> 2, pnd->addrs))
 132                 err = -EEXIST;
 133         spin_unlock_bh(&pndevs->lock);
 134         return err;
 135 }
 136
 137 int phonet_address_del(struct net_device *dev, u8 addr)
 138 {
 139         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 140         struct phonet_device *pnd;
 141         int err = 0;
 142
 143         spin_lock_bh(&pndevs->lock);
 144         pnd = __phonet_get(dev);
 145         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs))
 146                 err = -EADDRNOTAVAIL;
 147         else if (bitmap_empty(pnd->addrs, 64)) {
 148                 list_del(&pnd->list);
 149                 kfree(pnd);
 150         }
 151         spin_unlock_bh(&pndevs->lock);
 152         return err;
 153 }
 154
 155 /* Gets a source address toward a destination, through a interface. */
 156 u8 phonet_address_get(struct net_device *dev, u8 addr)
 157 {
 158         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 159         struct phonet_device *pnd;
 160
 161         spin_lock_bh(&pndevs->lock);
 162         pnd = __phonet_get(dev);
 163         if (pnd) {
 164                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 165
 166                 /* Use same source address as destination, if possible */
 167                 if (!test_bit(addr >> 2, pnd->addrs))
 168                         addr = find_first_bit(pnd->addrs, 64) << 2;
 169         } else
 170                 addr = PN_NO_ADDR;
 171         spin_unlock_bh(&pndevs->lock);
 172         return addr;
 173 }
 174
 175 int phonet_address_lookup(struct net *net, u8 addr)
 176 {
 177         struct phonet_device_list *pndevs = phonet_device_list(net);
 178         struct phonet_device *pnd;
 179         int err = -EADDRNOTAVAIL;
 180
 181         spin_lock_bh(&pndevs->lock);
 182         list_for_each_entry(pnd, &pndevs->list, list) {
 183                 /* Don't allow unregistering devices! */
 184                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 185                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 186                         continue;
 187
 188                 if (test_bit(addr >> 2, pnd->addrs)) {
 189                         err = 0;
 190                         goto found;
 191                 }
 192         }
 193 found:
 194         spin_unlock_bh(&pndevs->lock);
 195         return err;
 196 }
 197
 198 /* notify Phonet of device events */
 199 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 200                                 void *arg)
 201 {
 202         struct net_device *dev = arg;
 203
 204         if (what == NETDEV_UNREGISTER)
 205                 phonet_device_destroy(dev);
 206         return 0;
 207
 208 }
 209
 210 static struct notifier_block phonet_device_notifier = {
 211         .notifier_call = phonet_device_notify,
 212         .priority = 0,
 213 };
 214
 215 /* Per-namespace Phonet devices handling */
 216 static int phonet_init_net(struct net *net)
 217 {
 218         struct phonet_net *pnn = kmalloc(sizeof(*pnn), GFP_KERNEL);
 219         if (!pnn)
 220                 return -ENOMEM;
 221
 222         if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops)) {
 223                 kfree(pnn);
 224                 return -ENOMEM;
 225         }
 226
 227         INIT_LIST_HEAD(&pnn->pndevs.list);
 228         spin_lock_init(&pnn->pndevs.lock);
 229         net_assign_generic(net, phonet_net_id, pnn);
 230         return 0;
 231 }
 232
 233 static void phonet_exit_net(struct net *net)
 234 {
 235         struct phonet_net *pnn = net_generic(net, phonet_net_id);
 236         struct net_device *dev;
 237
 238         rtnl_lock();
 239         for_each_netdev(net, dev)
 240                 phonet_device_destroy(dev);
 241         rtnl_unlock();
 242
 243         proc_net_remove(net, "phonet");
 244         kfree(pnn);
 245 }
 246
 247 static struct pernet_operations phonet_net_ops = {
 248         .init = phonet_init_net,
 249         .exit = phonet_exit_net,
 250 };
 251
 252 /* Initialize Phonet devices list */
 253 int __init phonet_device_init(void)
 254 {
 255         int err = register_pernet_gen_device(&phonet_net_id, &phonet_net_ops);
 256         if (err)
 257                 return err;
 258
 259         register_netdevice_notifier(&phonet_device_notifier);
 260         err = phonet_netlink_register();
 261         if (err)
 262                 phonet_device_exit();
 263         return err;
 264 }
 265
 266 void phonet_device_exit(void)
 267 {
 268         rtnl_unregister_all(PF_PHONET);
 269         unregister_netdevice_notifier(&phonet_device_notifier);
 270         unregister_pernet_gen_device(phonet_net_id, &phonet_net_ops);
 271 }