net/phonet/pn_dev.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * File: pn_dev.c
   4  *
   5  * Phonet network device
   6  *
   7  * Copyright (C) 2008 Nokia Corporation.
   8  *
   9  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
  10  *          Rémi Denis-Courmont
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/net.h>
  15 #include <linux/slab.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/phonet.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/if_arp.h>
  20 #include <net/sock.h>
  21 #include <net/netns/generic.h>
  22 #include <net/phonet/pn_dev.h>
  23
  24 struct phonet_routes {
  25         spinlock_t              lock;
  26         struct net_device __rcu *table[64];
  27 };
  28
  29 struct phonet_net {
  30         struct phonet_device_list pndevs;
  31         struct phonet_routes routes;
  32 };
  33
  34 static unsigned int phonet_net_id __read_mostly;
  35
  36 static struct phonet_net *phonet_pernet(struct net *net)
  37 {
  38         return net_generic(net, phonet_net_id);
  39 }
  40
  41 struct phonet_device_list *phonet_device_list(struct net *net)
  42 {
  43         struct phonet_net *pnn = phonet_pernet(net);
  44         return &pnn->pndevs;
  45 }
  46
  47 /* Allocate new Phonet device. */
  48 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
  49 {
  50         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  51         struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
  52         if (pnd == NULL)
  53                 return NULL;
  54         pnd->netdev = dev;
  55         bitmap_zero(pnd->addrs, 64);
  56
  57         lockdep_assert_held(&pndevs->lock);
  58         list_add_rcu(&pnd->list, &pndevs->list);
  59         return pnd;
  60 }
  61
  62 static struct phonet_device *__phonet_get(struct net_device *dev)
  63 {
  64         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  65         struct phonet_device *pnd;
  66
  67         lockdep_assert_held(&pndevs->lock);
  68
  69         list_for_each_entry(pnd, &pndevs->list, list) {
  70                 if (pnd->netdev == dev)
  71                         return pnd;
  72         }
  73         return NULL;
  74 }
  75
  76 static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
  77 {
  78         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  79         struct phonet_device *pnd;
  80
  81         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
  82                 if (pnd->netdev == dev)
  83                         return pnd;
  84         }
  85         return NULL;
  86 }
  87
  88 static void phonet_device_destroy(struct net_device *dev)
  89 {
  90         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  91         struct phonet_device *pnd;
  92
  93         ASSERT_RTNL();
  94
  95         spin_lock(&pndevs->lock);
  96
  97         pnd = __phonet_get(dev);
  98         if (pnd)
  99                 list_del_rcu(&pnd->list);
 100
 101         spin_unlock(&pndevs->lock);
 102
 103         if (pnd) {
 104                 struct net *net = dev_net(dev);
 105                 u32 ifindex = dev->ifindex;
 106                 u8 addr;
 107
 108                 for_each_set_bit(addr, pnd->addrs, 64)
 109                         phonet_address_notify(net, RTM_DELADDR, ifindex, addr);
 110
 111                 kfree(pnd);
 112         }
 113 }
 114
 115 struct net_device *phonet_device_get(struct net *net)
 116 {
 117         struct phonet_device_list *pndevs = phonet_device_list(net);
 118         struct phonet_device *pnd;
 119         struct net_device *dev = NULL;
 120
 121         rcu_read_lock();
 122         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 123                 dev = pnd->netdev;
 124                 BUG_ON(!dev);
 125
 126                 if ((dev->reg_state == NETREG_REGISTERED) &&
 127                         ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
 128                         break;
 129                 dev = NULL;
 130         }
 131         dev_hold(dev);
 132         rcu_read_unlock();
 133         return dev;
 134 }
 135
 136 int phonet_address_add(struct net_device *dev, u8 addr)
 137 {
 138         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 139         struct phonet_device *pnd;
 140         int err = 0;
 141
 142         spin_lock(&pndevs->lock);
 143
 144         /* Find or create Phonet-specific device data */
 145         pnd = __phonet_get(dev);
 146         if (pnd == NULL)
 147                 pnd = __phonet_device_alloc(dev);
 148         if (unlikely(pnd == NULL))
 149                 err = -ENOMEM;
 150         else if (test_and_set_bit(addr >> 2, pnd->addrs))
 151                 err = -EEXIST;
 152
 153         spin_unlock(&pndevs->lock);
 154
 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         spin_lock(&pndevs->lock);
 165
 166         pnd = __phonet_get(dev);
 167         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
 168                 err = -EADDRNOTAVAIL;
 169                 pnd = NULL;
 170         } else if (bitmap_empty(pnd->addrs, 64))
 171                 list_del_rcu(&pnd->list);
 172         else
 173                 pnd = NULL;
 174
 175         spin_unlock(&pndevs->lock);
 176
 177         if (pnd)
 178                 kfree_rcu(pnd, rcu);
 179
 180         return err;
 181 }
 182
 183 /* Gets a source address toward a destination, through a interface. */
 184 u8 phonet_address_get(struct net_device *dev, u8 daddr)
 185 {
 186         struct phonet_device *pnd;
 187         u8 saddr;
 188
 189         rcu_read_lock();
 190         pnd = __phonet_get_rcu(dev);
 191         if (pnd) {
 192                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 193
 194                 /* Use same source address as destination, if possible */
 195                 if (test_bit(daddr >> 2, pnd->addrs))
 196                         saddr = daddr;
 197                 else
 198                         saddr = find_first_bit(pnd->addrs, 64) << 2;
 199         } else
 200                 saddr = PN_NO_ADDR;
 201         rcu_read_unlock();
 202
 203         if (saddr == PN_NO_ADDR) {
 204                 /* Fallback to another device */
 205                 struct net_device *def_dev;
 206
 207                 def_dev = phonet_device_get(dev_net(dev));
 208                 if (def_dev) {
 209                         if (def_dev != dev)
 210                                 saddr = phonet_address_get(def_dev, daddr);
 211                         dev_put(def_dev);
 212                 }
 213         }
 214         return saddr;
 215 }
 216
 217 int phonet_address_lookup(struct net *net, u8 addr)
 218 {
 219         struct phonet_device_list *pndevs = phonet_device_list(net);
 220         struct phonet_device *pnd;
 221         int err = -EADDRNOTAVAIL;
 222
 223         rcu_read_lock();
 224         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 225                 /* Don't allow unregistering devices! */
 226                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 227                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 228                         continue;
 229
 230                 if (test_bit(addr >> 2, pnd->addrs)) {
 231                         err = 0;
 232                         goto found;
 233                 }
 234         }
 235 found:
 236         rcu_read_unlock();
 237         return err;
 238 }
 239
 240 /* automatically configure a Phonet device, if supported */
 241 static int phonet_device_autoconf(struct net_device *dev)
 242 {
 243         struct if_phonet_req req;
 244         int ret;
 245
 246         if (!dev->netdev_ops->ndo_siocdevprivate)
 247                 return -EOPNOTSUPP;
 248
 249         ret = dev->netdev_ops->ndo_siocdevprivate(dev, (struct ifreq *)&req,
 250                                                   NULL, SIOCPNGAUTOCONF);
 251         if (ret < 0)
 252                 return ret;
 253
 254         ASSERT_RTNL();
 255         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
 256         if (ret)
 257                 return ret;
 258
 259         phonet_address_notify(dev_net(dev), RTM_NEWADDR, dev->ifindex,
 260                               req.ifr_phonet_autoconf.device);
 261         return 0;
 262 }
 263
 264 static void phonet_route_autodel(struct net_device *dev)
 265 {
 266         struct net *net = dev_net(dev);
 267         DECLARE_BITMAP(deleted, 64);
 268         u32 ifindex = dev->ifindex;
 269         struct phonet_net *pnn;
 270         unsigned int i;
 271
 272         pnn = phonet_pernet(net);
 273
 274         /* Remove left-over Phonet routes */
 275         bitmap_zero(deleted, 64);
 276
 277         spin_lock(&pnn->routes.lock);
 278         for (i = 0; i < 64; i++) {
 279                 if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
 280                         RCU_INIT_POINTER(pnn->routes.table[i], NULL);
 281                         set_bit(i, deleted);
 282                 }
 283         }
 284         spin_unlock(&pnn->routes.lock);
 285
 286         if (bitmap_empty(deleted, 64))
 287                 return; /* short-circuit RCU */
 288         synchronize_rcu();
 289         for_each_set_bit(i, deleted, 64) {
 290                 rtm_phonet_notify(net, RTM_DELROUTE, ifindex, i);
 291                 dev_put(dev);
 292         }
 293 }
 294
 295 /* notify Phonet of device events */
 296 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 297                                 void *ptr)
 298 {
 299         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 300
 301         switch (what) {
 302         case NETDEV_REGISTER:
 303                 if (dev->type == ARPHRD_PHONET)
 304                         phonet_device_autoconf(dev);
 305                 break;
 306         case NETDEV_UNREGISTER:
 307                 phonet_device_destroy(dev);
 308                 phonet_route_autodel(dev);
 309                 break;
 310         }
 311         return 0;
 312
 313 }
 314
 315 static struct notifier_block phonet_device_notifier = {
 316         .notifier_call = phonet_device_notify,
 317         .priority = 0,
 318 };
 319
 320 /* Per-namespace Phonet devices handling */
 321 static int __net_init phonet_init_net(struct net *net)
 322 {
 323         struct phonet_net *pnn = phonet_pernet(net);
 324
 325         if (!proc_create_net("phonet", 0, net->proc_net, &pn_sock_seq_ops,
 326                         sizeof(struct seq_net_private)))
 327                 return -ENOMEM;
 328
 329         INIT_LIST_HEAD(&pnn->pndevs.list);
 330         spin_lock_init(&pnn->pndevs.lock);
 331         spin_lock_init(&pnn->routes.lock);
 332         return 0;
 333 }
 334
 335 static void __net_exit phonet_exit_net(struct net *net)
 336 {
 337         struct phonet_net *pnn = phonet_pernet(net);
 338
 339         remove_proc_entry("phonet", net->proc_net);
 340         WARN_ON_ONCE(!list_empty(&pnn->pndevs.list));
 341 }
 342
 343 static struct pernet_operations phonet_net_ops = {
 344         .init = phonet_init_net,
 345         .exit = phonet_exit_net,
 346         .id   = &phonet_net_id,
 347         .size = sizeof(struct phonet_net),
 348 };
 349
 350 /* Initialize Phonet devices list */
 351 int __init phonet_device_init(void)
 352 {
 353         int err = register_pernet_subsys(&phonet_net_ops);
 354         if (err)
 355                 return err;
 356
 357         proc_create_net("pnresource", 0, init_net.proc_net, &pn_res_seq_ops,
 358                         sizeof(struct seq_net_private));
 359         register_netdevice_notifier(&phonet_device_notifier);
 360         err = phonet_netlink_register();
 361         if (err)
 362                 phonet_device_exit();
 363         return err;
 364 }
 365
 366 void phonet_device_exit(void)
 367 {
 368         rtnl_unregister_all(PF_PHONET);
 369         unregister_netdevice_notifier(&phonet_device_notifier);
 370         unregister_pernet_subsys(&phonet_net_ops);
 371         remove_proc_entry("pnresource", init_net.proc_net);
 372 }
 373
 374 int phonet_route_add(struct net_device *dev, u8 daddr)
 375 {
 376         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 377         struct phonet_routes *routes = &pnn->routes;
 378         int err = -EEXIST;
 379
 380         daddr = daddr >> 2;
 381
 382         spin_lock(&routes->lock);
 383         if (routes->table[daddr] == NULL) {
 384                 rcu_assign_pointer(routes->table[daddr], dev);
 385                 dev_hold(dev);
 386                 err = 0;
 387         }
 388         spin_unlock(&routes->lock);
 389
 390         return err;
 391 }
 392
 393 int phonet_route_del(struct net_device *dev, u8 daddr)
 394 {
 395         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 396         struct phonet_routes *routes = &pnn->routes;
 397
 398         daddr = daddr >> 2;
 399
 400         spin_lock(&routes->lock);
 401         if (rcu_access_pointer(routes->table[daddr]) == dev)
 402                 RCU_INIT_POINTER(routes->table[daddr], NULL);
 403         else
 404                 dev = NULL;
 405         spin_unlock(&routes->lock);
 406
 407         if (!dev)
 408                 return -ENOENT;
 409
 410         /* Note : our caller must call synchronize_rcu() and dev_put(dev) */
 411
 412         return 0;
 413 }
 414
 415 struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
 416 {
 417         struct phonet_net *pnn = phonet_pernet(net);
 418         struct phonet_routes *routes = &pnn->routes;
 419         struct net_device *dev;
 420
 421         daddr >>= 2;
 422         dev = rcu_dereference(routes->table[daddr]);
 423         return dev;
 424 }
 425
 426 struct net_device *phonet_route_output(struct net *net, u8 daddr)
 427 {
 428         struct phonet_net *pnn = phonet_pernet(net);
 429         struct phonet_routes *routes = &pnn->routes;
 430         struct net_device *dev;
 431
 432         daddr >>= 2;
 433         rcu_read_lock();
 434         dev = rcu_dereference(routes->table[daddr]);
 435         dev_hold(dev);
 436         rcu_read_unlock();
 437
 438         if (!dev)
 439                 dev = phonet_device_get(net); /* Default route */
 440         return dev;
 441 }