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 static void phonet_device_rcu_free(struct rcu_head *head)
 166 {
 167         struct phonet_device *pnd;
 168
 169         pnd = container_of(head, struct phonet_device, rcu);
 170         kfree(pnd);
 171 }
 172
 173 int phonet_address_del(struct net_device *dev, u8 addr)
 174 {
 175         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 176         struct phonet_device *pnd;
 177         int err = 0;
 178
 179         mutex_lock(&pndevs->lock);
 180         pnd = __phonet_get(dev);
 181         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
 182                 err = -EADDRNOTAVAIL;
 183                 pnd = NULL;
 184         } else if (bitmap_empty(pnd->addrs, 64))
 185                 list_del_rcu(&pnd->list);
 186         else
 187                 pnd = NULL;
 188         mutex_unlock(&pndevs->lock);
 189
 190         if (pnd)
 191                 call_rcu(&pnd->rcu, phonet_device_rcu_free);
 192
 193         return err;
 194 }
 195
 196 /* Gets a source address toward a destination, through a interface. */
 197 u8 phonet_address_get(struct net_device *dev, u8 daddr)
 198 {
 199         struct phonet_device *pnd;
 200         u8 saddr;
 201
 202         rcu_read_lock();
 203         pnd = __phonet_get_rcu(dev);
 204         if (pnd) {
 205                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 206
 207                 /* Use same source address as destination, if possible */
 208                 if (test_bit(daddr >> 2, pnd->addrs))
 209                         saddr = daddr;
 210                 else
 211                         saddr = find_first_bit(pnd->addrs, 64) << 2;
 212         } else
 213                 saddr = PN_NO_ADDR;
 214         rcu_read_unlock();
 215
 216         if (saddr == PN_NO_ADDR) {
 217                 /* Fallback to another device */
 218                 struct net_device *def_dev;
 219
 220                 def_dev = phonet_device_get(dev_net(dev));
 221                 if (def_dev) {
 222                         if (def_dev != dev)
 223                                 saddr = phonet_address_get(def_dev, daddr);
 224                         dev_put(def_dev);
 225                 }
 226         }
 227         return saddr;
 228 }
 229
 230 int phonet_address_lookup(struct net *net, u8 addr)
 231 {
 232         struct phonet_device_list *pndevs = phonet_device_list(net);
 233         struct phonet_device *pnd;
 234         int err = -EADDRNOTAVAIL;
 235
 236         rcu_read_lock();
 237         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 238                 /* Don't allow unregistering devices! */
 239                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 240                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 241                         continue;
 242
 243                 if (test_bit(addr >> 2, pnd->addrs)) {
 244                         err = 0;
 245                         goto found;
 246                 }
 247         }
 248 found:
 249         rcu_read_unlock();
 250         return err;
 251 }
 252
 253 /* automatically configure a Phonet device, if supported */
 254 static int phonet_device_autoconf(struct net_device *dev)
 255 {
 256         struct if_phonet_req req;
 257         int ret;
 258
 259         if (!dev->netdev_ops->ndo_do_ioctl)
 260                 return -EOPNOTSUPP;
 261
 262         ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
 263                                                 SIOCPNGAUTOCONF);
 264         if (ret < 0)
 265                 return ret;
 266
 267         ASSERT_RTNL();
 268         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
 269         if (ret)
 270                 return ret;
 271         phonet_address_notify(RTM_NEWADDR, dev,
 272                                 req.ifr_phonet_autoconf.device);
 273         return 0;
 274 }
 275
 276 static void phonet_route_autodel(struct net_device *dev)
 277 {
 278         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 279         unsigned i;
 280         DECLARE_BITMAP(deleted, 64);
 281
 282         /* Remove left-over Phonet routes */
 283         bitmap_zero(deleted, 64);
 284         mutex_lock(&pnn->routes.lock);
 285         for (i = 0; i < 64; i++)
 286                 if (dev == pnn->routes.table[i]) {
 287                         rcu_assign_pointer(pnn->routes.table[i], NULL);
 288                         set_bit(i, deleted);
 289                 }
 290         mutex_unlock(&pnn->routes.lock);
 291
 292         if (bitmap_empty(deleted, 64))
 293                 return; /* short-circuit RCU */
 294         synchronize_rcu();
 295         for (i = find_first_bit(deleted, 64); i < 64;
 296                         i = find_next_bit(deleted, 64, i + 1)) {
 297                 rtm_phonet_notify(RTM_DELROUTE, dev, i);
 298                 dev_put(dev);
 299         }
 300 }
 301
 302 /* notify Phonet of device events */
 303 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 304                                 void *arg)
 305 {
 306         struct net_device *dev = arg;
 307
 308         switch (what) {
 309         case NETDEV_REGISTER:
 310                 if (dev->type == ARPHRD_PHONET)
 311                         phonet_device_autoconf(dev);
 312                 break;
 313         case NETDEV_UNREGISTER:
 314                 phonet_device_destroy(dev);
 315                 phonet_route_autodel(dev);
 316                 break;
 317         }
 318         return 0;
 319
 320 }
 321
 322 static struct notifier_block phonet_device_notifier = {
 323         .notifier_call = phonet_device_notify,
 324         .priority = 0,
 325 };
 326
 327 /* Per-namespace Phonet devices handling */
 328 static int __net_init phonet_init_net(struct net *net)
 329 {
 330         struct phonet_net *pnn = phonet_pernet(net);
 331
 332         if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops))
 333                 return -ENOMEM;
 334
 335         INIT_LIST_HEAD(&pnn->pndevs.list);
 336         mutex_init(&pnn->pndevs.lock);
 337         mutex_init(&pnn->routes.lock);
 338         return 0;
 339 }
 340
 341 static void __net_exit phonet_exit_net(struct net *net)
 342 {
 343         struct phonet_net *pnn = phonet_pernet(net);
 344         struct net_device *dev;
 345         unsigned i;
 346
 347         rtnl_lock();
 348         for_each_netdev(net, dev)
 349                 phonet_device_destroy(dev);
 350
 351         for (i = 0; i < 64; i++) {
 352                 dev = pnn->routes.table[i];
 353                 if (dev) {
 354                         rtm_phonet_notify(RTM_DELROUTE, dev, i);
 355                         dev_put(dev);
 356                 }
 357         }
 358         rtnl_unlock();
 359
 360         proc_net_remove(net, "phonet");
 361 }
 362
 363 static struct pernet_operations phonet_net_ops = {
 364         .init = phonet_init_net,
 365         .exit = phonet_exit_net,
 366         .id   = &phonet_net_id,
 367         .size = sizeof(struct phonet_net),
 368 };
 369
 370 /* Initialize Phonet devices list */
 371 int __init phonet_device_init(void)
 372 {
 373         int err = register_pernet_device(&phonet_net_ops);
 374         if (err)
 375                 return err;
 376
 377         register_netdevice_notifier(&phonet_device_notifier);
 378         err = phonet_netlink_register();
 379         if (err)
 380                 phonet_device_exit();
 381         return err;
 382 }
 383
 384 void phonet_device_exit(void)
 385 {
 386         rtnl_unregister_all(PF_PHONET);
 387         unregister_netdevice_notifier(&phonet_device_notifier);
 388         unregister_pernet_device(&phonet_net_ops);
 389 }
 390
 391 int phonet_route_add(struct net_device *dev, u8 daddr)
 392 {
 393         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 394         struct phonet_routes *routes = &pnn->routes;
 395         int err = -EEXIST;
 396
 397         daddr = daddr >> 2;
 398         mutex_lock(&routes->lock);
 399         if (routes->table[daddr] == NULL) {
 400                 rcu_assign_pointer(routes->table[daddr], dev);
 401                 dev_hold(dev);
 402                 err = 0;
 403         }
 404         mutex_unlock(&routes->lock);
 405         return err;
 406 }
 407
 408 int phonet_route_del(struct net_device *dev, u8 daddr)
 409 {
 410         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 411         struct phonet_routes *routes = &pnn->routes;
 412
 413         daddr = daddr >> 2;
 414         mutex_lock(&routes->lock);
 415         if (dev == routes->table[daddr])
 416                 rcu_assign_pointer(routes->table[daddr], NULL);
 417         else
 418                 dev = NULL;
 419         mutex_unlock(&routes->lock);
 420
 421         if (!dev)
 422                 return -ENOENT;
 423         synchronize_rcu();
 424         dev_put(dev);
 425         return 0;
 426 }
 427
 428 struct net_device *phonet_route_get(struct net *net, u8 daddr)
 429 {
 430         struct phonet_net *pnn = phonet_pernet(net);
 431         struct phonet_routes *routes = &pnn->routes;
 432         struct net_device *dev;
 433
 434         ASSERT_RTNL(); /* no need to hold the device */
 435
 436         daddr >>= 2;
 437         rcu_read_lock();
 438         dev = rcu_dereference(routes->table[daddr]);
 439         rcu_read_unlock();
 440         return dev;
 441 }
 442
 443 struct net_device *phonet_route_output(struct net *net, u8 daddr)
 444 {
 445         struct phonet_net *pnn = phonet_pernet(net);
 446         struct phonet_routes *routes = &pnn->routes;
 447         struct net_device *dev;
 448
 449         daddr >>= 2;
 450         rcu_read_lock();
 451         dev = rcu_dereference(routes->table[daddr]);
 452         if (dev)
 453                 dev_hold(dev);
 454         rcu_read_unlock();
 455
 456         if (!dev)
 457                 dev = phonet_device_get(net); /* Default route */
 458         return dev;
 459 }