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