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