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  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
   9  *          Rémi Denis-Courmont
  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 __rcu *table[64];
  40 };
  41
  42 struct phonet_net {
  43         struct phonet_device_list pndevs;
  44         struct phonet_routes routes;
  45 };
  46
  47 static unsigned 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                 kfree_rcu(pnd, rcu);
 184
 185         return err;
 186 }
 187
 188 /* Gets a source address toward a destination, through a interface. */
 189 u8 phonet_address_get(struct net_device *dev, u8 daddr)
 190 {
 191         struct phonet_device *pnd;
 192         u8 saddr;
 193
 194         rcu_read_lock();
 195         pnd = __phonet_get_rcu(dev);
 196         if (pnd) {
 197                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 198
 199                 /* Use same source address as destination, if possible */
 200                 if (test_bit(daddr >> 2, pnd->addrs))
 201                         saddr = daddr;
 202                 else
 203                         saddr = find_first_bit(pnd->addrs, 64) << 2;
 204         } else
 205                 saddr = PN_NO_ADDR;
 206         rcu_read_unlock();
 207
 208         if (saddr == PN_NO_ADDR) {
 209                 /* Fallback to another device */
 210                 struct net_device *def_dev;
 211
 212                 def_dev = phonet_device_get(dev_net(dev));
 213                 if (def_dev) {
 214                         if (def_dev != dev)
 215                                 saddr = phonet_address_get(def_dev, daddr);
 216                         dev_put(def_dev);
 217                 }
 218         }
 219         return saddr;
 220 }
 221
 222 int phonet_address_lookup(struct net *net, u8 addr)
 223 {
 224         struct phonet_device_list *pndevs = phonet_device_list(net);
 225         struct phonet_device *pnd;
 226         int err = -EADDRNOTAVAIL;
 227
 228         rcu_read_lock();
 229         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 230                 /* Don't allow unregistering devices! */
 231                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 232                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 233                         continue;
 234
 235                 if (test_bit(addr >> 2, pnd->addrs)) {
 236                         err = 0;
 237                         goto found;
 238                 }
 239         }
 240 found:
 241         rcu_read_unlock();
 242         return err;
 243 }
 244
 245 /* automatically configure a Phonet device, if supported */
 246 static int phonet_device_autoconf(struct net_device *dev)
 247 {
 248         struct if_phonet_req req;
 249         int ret;
 250
 251         if (!dev->netdev_ops->ndo_do_ioctl)
 252                 return -EOPNOTSUPP;
 253
 254         ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
 255                                                 SIOCPNGAUTOCONF);
 256         if (ret < 0)
 257                 return ret;
 258
 259         ASSERT_RTNL();
 260         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
 261         if (ret)
 262                 return ret;
 263         phonet_address_notify(RTM_NEWADDR, dev,
 264                                 req.ifr_phonet_autoconf.device);
 265         return 0;
 266 }
 267
 268 static void phonet_route_autodel(struct net_device *dev)
 269 {
 270         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 271         unsigned int i;
 272         DECLARE_BITMAP(deleted, 64);
 273
 274         /* Remove left-over Phonet routes */
 275         bitmap_zero(deleted, 64);
 276         mutex_lock(&pnn->routes.lock);
 277         for (i = 0; i < 64; i++)
 278                 if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
 279                         RCU_INIT_POINTER(pnn->routes.table[i], NULL);
 280                         set_bit(i, deleted);
 281                 }
 282         mutex_unlock(&pnn->routes.lock);
 283
 284         if (bitmap_empty(deleted, 64))
 285                 return; /* short-circuit RCU */
 286         synchronize_rcu();
 287         for_each_set_bit(i, deleted, 64) {
 288                 rtm_phonet_notify(RTM_DELROUTE, dev, i);
 289                 dev_put(dev);
 290         }
 291 }
 292
 293 /* notify Phonet of device events */
 294 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 295                                 void *ptr)
 296 {
 297         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 298
 299         switch (what) {
 300         case NETDEV_REGISTER:
 301                 if (dev->type == ARPHRD_PHONET)
 302                         phonet_device_autoconf(dev);
 303                 break;
 304         case NETDEV_UNREGISTER:
 305                 phonet_device_destroy(dev);
 306                 phonet_route_autodel(dev);
 307                 break;
 308         }
 309         return 0;
 310
 311 }
 312
 313 static struct notifier_block phonet_device_notifier = {
 314         .notifier_call = phonet_device_notify,
 315         .priority = 0,
 316 };
 317
 318 /* Per-namespace Phonet devices handling */
 319 static int __net_init phonet_init_net(struct net *net)
 320 {
 321         struct phonet_net *pnn = phonet_pernet(net);
 322
 323         if (!proc_create("phonet", 0, net->proc_net, &pn_sock_seq_fops))
 324                 return -ENOMEM;
 325
 326         INIT_LIST_HEAD(&pnn->pndevs.list);
 327         mutex_init(&pnn->pndevs.lock);
 328         mutex_init(&pnn->routes.lock);
 329         return 0;
 330 }
 331
 332 static void __net_exit phonet_exit_net(struct net *net)
 333 {
 334         struct phonet_net *pnn = phonet_pernet(net);
 335
 336         remove_proc_entry("phonet", net->proc_net);
 337         WARN_ON_ONCE(!list_empty(&pnn->pndevs.list));
 338 }
 339
 340 static struct pernet_operations phonet_net_ops = {
 341         .init = phonet_init_net,
 342         .exit = phonet_exit_net,
 343         .id   = &phonet_net_id,
 344         .size = sizeof(struct phonet_net),
 345 };
 346
 347 /* Initialize Phonet devices list */
 348 int __init phonet_device_init(void)
 349 {
 350         int err = register_pernet_subsys(&phonet_net_ops);
 351         if (err)
 352                 return err;
 353
 354         proc_create("pnresource", 0, init_net.proc_net, &pn_res_seq_fops);
 355         register_netdevice_notifier(&phonet_device_notifier);
 356         err = phonet_netlink_register();
 357         if (err)
 358                 phonet_device_exit();
 359         return err;
 360 }
 361
 362 void phonet_device_exit(void)
 363 {
 364         rtnl_unregister_all(PF_PHONET);
 365         unregister_netdevice_notifier(&phonet_device_notifier);
 366         unregister_pernet_subsys(&phonet_net_ops);
 367         remove_proc_entry("pnresource", init_net.proc_net);
 368 }
 369
 370 int phonet_route_add(struct net_device *dev, u8 daddr)
 371 {
 372         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 373         struct phonet_routes *routes = &pnn->routes;
 374         int err = -EEXIST;
 375
 376         daddr = daddr >> 2;
 377         mutex_lock(&routes->lock);
 378         if (routes->table[daddr] == NULL) {
 379                 rcu_assign_pointer(routes->table[daddr], dev);
 380                 dev_hold(dev);
 381                 err = 0;
 382         }
 383         mutex_unlock(&routes->lock);
 384         return err;
 385 }
 386
 387 int phonet_route_del(struct net_device *dev, u8 daddr)
 388 {
 389         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 390         struct phonet_routes *routes = &pnn->routes;
 391
 392         daddr = daddr >> 2;
 393         mutex_lock(&routes->lock);
 394         if (rcu_access_pointer(routes->table[daddr]) == dev)
 395                 RCU_INIT_POINTER(routes->table[daddr], NULL);
 396         else
 397                 dev = NULL;
 398         mutex_unlock(&routes->lock);
 399
 400         if (!dev)
 401                 return -ENOENT;
 402         synchronize_rcu();
 403         dev_put(dev);
 404         return 0;
 405 }
 406
 407 struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
 408 {
 409         struct phonet_net *pnn = phonet_pernet(net);
 410         struct phonet_routes *routes = &pnn->routes;
 411         struct net_device *dev;
 412
 413         daddr >>= 2;
 414         dev = rcu_dereference(routes->table[daddr]);
 415         return dev;
 416 }
 417
 418 struct net_device *phonet_route_output(struct net *net, u8 daddr)
 419 {
 420         struct phonet_net *pnn = phonet_pernet(net);
 421         struct phonet_routes *routes = &pnn->routes;
 422         struct net_device *dev;
 423
 424         daddr >>= 2;
 425         rcu_read_lock();
 426         dev = rcu_dereference(routes->table[daddr]);
 427         if (dev)
 428                 dev_hold(dev);
 429         rcu_read_unlock();
 430
 431         if (!dev)
 432                 dev = phonet_device_get(net); /* Default route */
 433         return dev;
 434 }