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