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/slab.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/phonet.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/if_arp.h>
  33 #include <net/sock.h>
  34 #include <net/netns/generic.h>
  35 #include <net/phonet/pn_dev.h>
  36
  37 struct phonet_routes {
  38         struct mutex            lock;
  39         struct net_device       *table[64];
  40 };
  41
  42 struct phonet_net {
  43         struct phonet_device_list pndevs;
  44         struct phonet_routes routes;
  45 };
  46
  47 int phonet_net_id __read_mostly;
  48
  49 static struct phonet_net *phonet_pernet(struct net *net)
  50 {
  51         BUG_ON(!net);
  52
  53         return net_generic(net, phonet_net_id);
  54 }
  55
  56 struct phonet_device_list *phonet_device_list(struct net *net)
  57 {
  58         struct phonet_net *pnn = phonet_pernet(net);
  59         return &pnn->pndevs;
  60 }
  61
  62 /* Allocate new Phonet device. */
  63 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
  64 {
  65         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  66         struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
  67         if (pnd == NULL)
  68                 return NULL;
  69         pnd->netdev = dev;
  70         bitmap_zero(pnd->addrs, 64);
  71
  72         BUG_ON(!mutex_is_locked(&pndevs->lock));
  73         list_add_rcu(&pnd->list, &pndevs->list);
  74         return pnd;
  75 }
  76
  77 static struct phonet_device *__phonet_get(struct net_device *dev)
  78 {
  79         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  80         struct phonet_device *pnd;
  81
  82         BUG_ON(!mutex_is_locked(&pndevs->lock));
  83         list_for_each_entry(pnd, &pndevs->list, list) {
  84                 if (pnd->netdev == dev)
  85                         return pnd;
  86         }
  87         return NULL;
  88 }
  89
  90 static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
  91 {
  92         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  93         struct phonet_device *pnd;
  94
  95         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
  96                 if (pnd->netdev == dev)
  97                         return pnd;
  98         }
  99         return NULL;
 100 }
 101
 102 static void phonet_device_destroy(struct net_device *dev)
 103 {
 104         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 105         struct phonet_device *pnd;
 106
 107         ASSERT_RTNL();
 108
 109         mutex_lock(&pndevs->lock);
 110         pnd = __phonet_get(dev);
 111         if (pnd)
 112                 list_del_rcu(&pnd->list);
 113         mutex_unlock(&pndevs->lock);
 114
 115         if (pnd) {
 116                 u8 addr;
 117
 118                 for_each_set_bit(addr, pnd->addrs, 64)
 119                         phonet_address_notify(RTM_DELADDR, dev, addr);
 120                 kfree(pnd);
 121         }
 122 }
 123
 124 struct net_device *phonet_device_get(struct net *net)
 125 {
 126         struct phonet_device_list *pndevs = phonet_device_list(net);
 127         struct phonet_device *pnd;
 128         struct net_device *dev = NULL;
 129
 130         rcu_read_lock();
 131         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 132                 dev = pnd->netdev;
 133                 BUG_ON(!dev);
 134
 135                 if ((dev->reg_state == NETREG_REGISTERED) &&
 136                         ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
 137                         break;
 138                 dev = NULL;
 139         }
 140         if (dev)
 141                 dev_hold(dev);
 142         rcu_read_unlock();
 143         return dev;
 144 }
 145
 146 int phonet_address_add(struct net_device *dev, u8 addr)
 147 {
 148         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 149         struct phonet_device *pnd;
 150         int err = 0;
 151
 152         mutex_lock(&pndevs->lock);
 153         /* Find or create Phonet-specific device data */
 154         pnd = __phonet_get(dev);
 155         if (pnd == NULL)
 156                 pnd = __phonet_device_alloc(dev);
 157         if (unlikely(pnd == NULL))
 158                 err = -ENOMEM;
 159         else if (test_and_set_bit(addr >> 2, pnd->addrs))
 160                 err = -EEXIST;
 161         mutex_unlock(&pndevs->lock);
 162         return err;
 163 }
 164
 165 int phonet_address_del(struct net_device *dev, u8 addr)
 166 {
 167         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 168         struct phonet_device *pnd;
 169         int err = 0;
 170
 171         mutex_lock(&pndevs->lock);
 172         pnd = __phonet_get(dev);
 173         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
 174                 err = -EADDRNOTAVAIL;
 175                 pnd = NULL;
 176         } else if (bitmap_empty(pnd->addrs, 64))
 177                 list_del_rcu(&pnd->list);
 178         else
 179                 pnd = NULL;
 180         mutex_unlock(&pndevs->lock);
 181
 182         if (pnd) {
 183                 synchronize_rcu();
 184                 kfree(pnd);
 185         }
 186         return err;
 187 }
 188
 189 /* Gets a source address toward a destination, through a interface. */
 190 u8 phonet_address_get(struct net_device *dev, u8 daddr)
 191 {
 192         struct phonet_device *pnd;
 193         u8 saddr;
 194
 195         rcu_read_lock();
 196         pnd = __phonet_get_rcu(dev);
 197         if (pnd) {
 198                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 199
 200                 /* Use same source address as destination, if possible */
 201                 if (test_bit(daddr >> 2, pnd->addrs))
 202                         saddr = daddr;
 203                 else
 204                         saddr = find_first_bit(pnd->addrs, 64) << 2;
 205         } else
 206                 saddr = PN_NO_ADDR;
 207         rcu_read_unlock();
 208
 209         if (saddr == PN_NO_ADDR) {
 210                 /* Fallback to another device */
 211                 struct net_device *def_dev;
 212
 213                 def_dev = phonet_device_get(dev_net(dev));
 214                 if (def_dev) {
 215                         if (def_dev != dev)
 216                                 saddr = phonet_address_get(def_dev, daddr);
 217                         dev_put(def_dev);
 218                 }
 219         }
 220         return saddr;
 221 }
 222
 223 int phonet_address_lookup(struct net *net, u8 addr)
 224 {
 225         struct phonet_device_list *pndevs = phonet_device_list(net);
 226         struct phonet_device *pnd;
 227         int err = -EADDRNOTAVAIL;
 228
 229         rcu_read_lock();
 230         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 231                 /* Don't allow unregistering devices! */
 232                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 233                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 234                         continue;
 235
 236                 if (test_bit(addr >> 2, pnd->addrs)) {
 237                         err = 0;
 238                         goto found;
 239                 }
 240         }
 241 found:
 242         rcu_read_unlock();
 243         return err;
 244 }
 245
 246 /* automatically configure a Phonet device, if supported */
 247 static int phonet_device_autoconf(struct net_device *dev)
 248 {
 249         struct if_phonet_req req;
 250         int ret;
 251
 252         if (!dev->netdev_ops->ndo_do_ioctl)
 253                 return -EOPNOTSUPP;
 254
 255         ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
 256                                                 SIOCPNGAUTOCONF);
 257         if (ret < 0)
 258                 return ret;
 259
 260         ASSERT_RTNL();
 261         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
 262         if (ret)
 263                 return ret;
 264         phonet_address_notify(RTM_NEWADDR, dev,
 265                                 req.ifr_phonet_autoconf.device);
 266         return 0;
 267 }
 268
 269 static void phonet_route_autodel(struct net_device *dev)
 270 {
 271         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 272         unsigned i;
 273         DECLARE_BITMAP(deleted, 64);
 274
 275         /* Remove left-over Phonet routes */
 276         bitmap_zero(deleted, 64);
 277         mutex_lock(&pnn->routes.lock);
 278         for (i = 0; i < 64; i++)
 279                 if (dev == pnn->routes.table[i]) {
 280                         rcu_assign_pointer(pnn->routes.table[i], NULL);
 281                         set_bit(i, deleted);
 282                 }
 283         mutex_unlock(&pnn->routes.lock);
 284
 285         if (bitmap_empty(deleted, 64))
 286                 return; /* short-circuit RCU */
 287         synchronize_rcu();
 288         for (i = find_first_bit(deleted, 64); i < 64;
 289                         i = find_next_bit(deleted, 64, i + 1)) {
 290                 rtm_phonet_notify(RTM_DELROUTE, dev, i);
 291                 dev_put(dev);
 292         }
 293 }
 294
 295 /* notify Phonet of device events */
 296 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 297                                 void *arg)
 298 {
 299         struct net_device *dev = arg;
 300
 301         switch (what) {
 302         case NETDEV_REGISTER:
 303                 if (dev->type == ARPHRD_PHONET)
 304                         phonet_device_autoconf(dev);
 305                 break;
 306         case NETDEV_UNREGISTER:
 307                 phonet_device_destroy(dev);
 308                 phonet_route_autodel(dev);
 309                 break;
 310         }
 311         return 0;
 312
 313 }
 314
 315 static struct notifier_block phonet_device_notifier = {
 316         .notifier_call = phonet_device_notify,
 317         .priority = 0,
 318 };
 319
 320 /* Per-namespace Phonet devices handling */
 321 static int __net_init phonet_init_net(struct net *net)
 322 {
 323         struct phonet_net *pnn = phonet_pernet(net);
 324
 325         if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops))
 326                 return -ENOMEM;
 327
 328         INIT_LIST_HEAD(&pnn->pndevs.list);
 329         mutex_init(&pnn->pndevs.lock);
 330         mutex_init(&pnn->routes.lock);
 331         return 0;
 332 }
 333
 334 static void __net_exit phonet_exit_net(struct net *net)
 335 {
 336         struct phonet_net *pnn = phonet_pernet(net);
 337         struct net_device *dev;
 338         unsigned i;
 339
 340         rtnl_lock();
 341         for_each_netdev(net, dev)
 342                 phonet_device_destroy(dev);
 343
 344         for (i = 0; i < 64; i++) {
 345                 dev = pnn->routes.table[i];
 346                 if (dev) {
 347                         rtm_phonet_notify(RTM_DELROUTE, dev, i);
 348                         dev_put(dev);
 349                 }
 350         }
 351         rtnl_unlock();
 352
 353         proc_net_remove(net, "phonet");
 354 }
 355
 356 static struct pernet_operations phonet_net_ops = {
 357         .init = phonet_init_net,
 358         .exit = phonet_exit_net,
 359         .id   = &phonet_net_id,
 360         .size = sizeof(struct phonet_net),
 361 };
 362
 363 /* Initialize Phonet devices list */
 364 int __init phonet_device_init(void)
 365 {
 366         int err = register_pernet_device(&phonet_net_ops);
 367         if (err)
 368                 return err;
 369
 370         register_netdevice_notifier(&phonet_device_notifier);
 371         err = phonet_netlink_register();
 372         if (err)
 373                 phonet_device_exit();
 374         return err;
 375 }
 376
 377 void phonet_device_exit(void)
 378 {
 379         rtnl_unregister_all(PF_PHONET);
 380         unregister_netdevice_notifier(&phonet_device_notifier);
 381         unregister_pernet_device(&phonet_net_ops);
 382 }
 383
 384 int phonet_route_add(struct net_device *dev, u8 daddr)
 385 {
 386         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 387         struct phonet_routes *routes = &pnn->routes;
 388         int err = -EEXIST;
 389
 390         daddr = daddr >> 2;
 391         mutex_lock(&routes->lock);
 392         if (routes->table[daddr] == NULL) {
 393                 rcu_assign_pointer(routes->table[daddr], dev);
 394                 dev_hold(dev);
 395                 err = 0;
 396         }
 397         mutex_unlock(&routes->lock);
 398         return err;
 399 }
 400
 401 int phonet_route_del(struct net_device *dev, u8 daddr)
 402 {
 403         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 404         struct phonet_routes *routes = &pnn->routes;
 405
 406         daddr = daddr >> 2;
 407         mutex_lock(&routes->lock);
 408         if (dev == routes->table[daddr])
 409                 rcu_assign_pointer(routes->table[daddr], NULL);
 410         else
 411                 dev = NULL;
 412         mutex_unlock(&routes->lock);
 413
 414         if (!dev)
 415                 return -ENOENT;
 416         synchronize_rcu();
 417         dev_put(dev);
 418         return 0;
 419 }
 420
 421 struct net_device *phonet_route_get(struct net *net, u8 daddr)
 422 {
 423         struct phonet_net *pnn = phonet_pernet(net);
 424         struct phonet_routes *routes = &pnn->routes;
 425         struct net_device *dev;
 426
 427         ASSERT_RTNL(); /* no need to hold the device */
 428
 429         daddr >>= 2;
 430         rcu_read_lock();
 431         dev = rcu_dereference(routes->table[daddr]);
 432         rcu_read_unlock();
 433         return dev;
 434 }
 435
 436 struct net_device *phonet_route_output(struct net *net, u8 daddr)
 437 {
 438         struct phonet_net *pnn = phonet_pernet(net);
 439         struct phonet_routes *routes = &pnn->routes;
 440         struct net_device *dev;
 441
 442         daddr >>= 2;
 443         rcu_read_lock();
 444         dev = rcu_dereference(routes->table[daddr]);
 445         if (dev)
 446                 dev_hold(dev);
 447         rcu_read_unlock();
 448
 449         if (!dev)
 450                 dev = phonet_device_get(net); /* Default route */
 451         return dev;
 452 }