linux/net/phonet/pn_dev.c
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   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 *          RĂ©mi 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
  24struct phonet_routes {
  25        struct mutex            lock;
  26        struct net_device __rcu *table[64];
  27};
  28
  29struct phonet_net {
  30        struct phonet_device_list pndevs;
  31        struct phonet_routes routes;
  32};
  33
  34static unsigned int phonet_net_id __read_mostly;
  35
  36static struct phonet_net *phonet_pernet(struct net *net)
  37{
  38        return net_generic(net, phonet_net_id);
  39}
  40
  41struct 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. */
  48static 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        BUG_ON(!mutex_is_locked(&pndevs->lock));
  58        list_add_rcu(&pnd->list, &pndevs->list);
  59        return pnd;
  60}
  61
  62static 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        BUG_ON(!mutex_is_locked(&pndevs->lock));
  68        list_for_each_entry(pnd, &pndevs->list, list) {
  69                if (pnd->netdev == dev)
  70                        return pnd;
  71        }
  72        return NULL;
  73}
  74
  75static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
  76{
  77        struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  78        struct phonet_device *pnd;
  79
  80        list_for_each_entry_rcu(pnd, &pndevs->list, list) {
  81                if (pnd->netdev == dev)
  82                        return pnd;
  83        }
  84        return NULL;
  85}
  86
  87static void phonet_device_destroy(struct net_device *dev)
  88{
  89        struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
  90        struct phonet_device *pnd;
  91
  92        ASSERT_RTNL();
  93
  94        mutex_lock(&pndevs->lock);
  95        pnd = __phonet_get(dev);
  96        if (pnd)
  97                list_del_rcu(&pnd->list);
  98        mutex_unlock(&pndevs->lock);
  99
 100        if (pnd) {
 101                u8 addr;
 102
 103                for_each_set_bit(addr, pnd->addrs, 64)
 104                        phonet_address_notify(RTM_DELADDR, dev, addr);
 105                kfree(pnd);
 106        }
 107}
 108
 109struct net_device *phonet_device_get(struct net *net)
 110{
 111        struct phonet_device_list *pndevs = phonet_device_list(net);
 112        struct phonet_device *pnd;
 113        struct net_device *dev = NULL;
 114
 115        rcu_read_lock();
 116        list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 117                dev = pnd->netdev;
 118                BUG_ON(!dev);
 119
 120                if ((dev->reg_state == NETREG_REGISTERED) &&
 121                        ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
 122                        break;
 123                dev = NULL;
 124        }
 125        if (dev)
 126                dev_hold(dev);
 127        rcu_read_unlock();
 128        return dev;
 129}
 130
 131int phonet_address_add(struct net_device *dev, u8 addr)
 132{
 133        struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 134        struct phonet_device *pnd;
 135        int err = 0;
 136
 137        mutex_lock(&pndevs->lock);
 138        /* Find or create Phonet-specific device data */
 139        pnd = __phonet_get(dev);
 140        if (pnd == NULL)
 141                pnd = __phonet_device_alloc(dev);
 142        if (unlikely(pnd == NULL))
 143                err = -ENOMEM;
 144        else if (test_and_set_bit(addr >> 2, pnd->addrs))
 145                err = -EEXIST;
 146        mutex_unlock(&pndevs->lock);
 147        return err;
 148}
 149
 150int phonet_address_del(struct net_device *dev, u8 addr)
 151{
 152        struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
 153        struct phonet_device *pnd;
 154        int err = 0;
 155
 156        mutex_lock(&pndevs->lock);
 157        pnd = __phonet_get(dev);
 158        if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
 159                err = -EADDRNOTAVAIL;
 160                pnd = NULL;
 161        } else if (bitmap_empty(pnd->addrs, 64))
 162                list_del_rcu(&pnd->list);
 163        else
 164                pnd = NULL;
 165        mutex_unlock(&pndevs->lock);
 166
 167        if (pnd)
 168                kfree_rcu(pnd, rcu);
 169
 170        return err;
 171}
 172
 173/* Gets a source address toward a destination, through a interface. */
 174u8 phonet_address_get(struct net_device *dev, u8 daddr)
 175{
 176        struct phonet_device *pnd;
 177        u8 saddr;
 178
 179        rcu_read_lock();
 180        pnd = __phonet_get_rcu(dev);
 181        if (pnd) {
 182                BUG_ON(bitmap_empty(pnd->addrs, 64));
 183
 184                /* Use same source address as destination, if possible */
 185                if (test_bit(daddr >> 2, pnd->addrs))
 186                        saddr = daddr;
 187                else
 188                        saddr = find_first_bit(pnd->addrs, 64) << 2;
 189        } else
 190                saddr = PN_NO_ADDR;
 191        rcu_read_unlock();
 192
 193        if (saddr == PN_NO_ADDR) {
 194                /* Fallback to another device */
 195                struct net_device *def_dev;
 196
 197                def_dev = phonet_device_get(dev_net(dev));
 198                if (def_dev) {
 199                        if (def_dev != dev)
 200                                saddr = phonet_address_get(def_dev, daddr);
 201                        dev_put(def_dev);
 202                }
 203        }
 204        return saddr;
 205}
 206
 207int phonet_address_lookup(struct net *net, u8 addr)
 208{
 209        struct phonet_device_list *pndevs = phonet_device_list(net);
 210        struct phonet_device *pnd;
 211        int err = -EADDRNOTAVAIL;
 212
 213        rcu_read_lock();
 214        list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 215                /* Don't allow unregistering devices! */
 216                if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 217                                ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 218                        continue;
 219
 220                if (test_bit(addr >> 2, pnd->addrs)) {
 221                        err = 0;
 222                        goto found;
 223                }
 224        }
 225found:
 226        rcu_read_unlock();
 227        return err;
 228}
 229
 230/* automatically configure a Phonet device, if supported */
 231static int phonet_device_autoconf(struct net_device *dev)
 232{
 233        struct if_phonet_req req;
 234        int ret;
 235
 236        if (!dev->netdev_ops->ndo_do_ioctl)
 237                return -EOPNOTSUPP;
 238
 239        ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
 240                                                SIOCPNGAUTOCONF);
 241        if (ret < 0)
 242                return ret;
 243
 244        ASSERT_RTNL();
 245        ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
 246        if (ret)
 247                return ret;
 248        phonet_address_notify(RTM_NEWADDR, dev,
 249                                req.ifr_phonet_autoconf.device);
 250        return 0;
 251}
 252
 253static void phonet_route_autodel(struct net_device *dev)
 254{
 255        struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 256        unsigned int i;
 257        DECLARE_BITMAP(deleted, 64);
 258
 259        /* Remove left-over Phonet routes */
 260        bitmap_zero(deleted, 64);
 261        mutex_lock(&pnn->routes.lock);
 262        for (i = 0; i < 64; i++)
 263                if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
 264                        RCU_INIT_POINTER(pnn->routes.table[i], NULL);
 265                        set_bit(i, deleted);
 266                }
 267        mutex_unlock(&pnn->routes.lock);
 268
 269        if (bitmap_empty(deleted, 64))
 270                return; /* short-circuit RCU */
 271        synchronize_rcu();
 272        for_each_set_bit(i, deleted, 64) {
 273                rtm_phonet_notify(RTM_DELROUTE, dev, i);
 274                dev_put(dev);
 275        }
 276}
 277
 278/* notify Phonet of device events */
 279static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 280                                void *ptr)
 281{
 282        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 283
 284        switch (what) {
 285        case NETDEV_REGISTER:
 286                if (dev->type == ARPHRD_PHONET)
 287                        phonet_device_autoconf(dev);
 288                break;
 289        case NETDEV_UNREGISTER:
 290                phonet_device_destroy(dev);
 291                phonet_route_autodel(dev);
 292                break;
 293        }
 294        return 0;
 295
 296}
 297
 298static struct notifier_block phonet_device_notifier = {
 299        .notifier_call = phonet_device_notify,
 300        .priority = 0,
 301};
 302
 303/* Per-namespace Phonet devices handling */
 304static int __net_init phonet_init_net(struct net *net)
 305{
 306        struct phonet_net *pnn = phonet_pernet(net);
 307
 308        if (!proc_create_net("phonet", 0, net->proc_net, &pn_sock_seq_ops,
 309                        sizeof(struct seq_net_private)))
 310                return -ENOMEM;
 311
 312        INIT_LIST_HEAD(&pnn->pndevs.list);
 313        mutex_init(&pnn->pndevs.lock);
 314        mutex_init(&pnn->routes.lock);
 315        return 0;
 316}
 317
 318static void __net_exit phonet_exit_net(struct net *net)
 319{
 320        struct phonet_net *pnn = phonet_pernet(net);
 321
 322        remove_proc_entry("phonet", net->proc_net);
 323        WARN_ON_ONCE(!list_empty(&pnn->pndevs.list));
 324}
 325
 326static struct pernet_operations phonet_net_ops = {
 327        .init = phonet_init_net,
 328        .exit = phonet_exit_net,
 329        .id   = &phonet_net_id,
 330        .size = sizeof(struct phonet_net),
 331};
 332
 333/* Initialize Phonet devices list */
 334int __init phonet_device_init(void)
 335{
 336        int err = register_pernet_subsys(&phonet_net_ops);
 337        if (err)
 338                return err;
 339
 340        proc_create_net("pnresource", 0, init_net.proc_net, &pn_res_seq_ops,
 341                        sizeof(struct seq_net_private));
 342        register_netdevice_notifier(&phonet_device_notifier);
 343        err = phonet_netlink_register();
 344        if (err)
 345                phonet_device_exit();
 346        return err;
 347}
 348
 349void phonet_device_exit(void)
 350{
 351        rtnl_unregister_all(PF_PHONET);
 352        unregister_netdevice_notifier(&phonet_device_notifier);
 353        unregister_pernet_subsys(&phonet_net_ops);
 354        remove_proc_entry("pnresource", init_net.proc_net);
 355}
 356
 357int phonet_route_add(struct net_device *dev, u8 daddr)
 358{
 359        struct phonet_net *pnn = phonet_pernet(dev_net(dev));
 360        struct phonet_routes *routes = &pnn->routes;
 361        int err = -EEXIST;
 362
 363        daddr = daddr >> 2;
 364        mutex_lock(&routes->lock);
 365        if (routes->table[daddr] == NULL) {
 366                rcu_assign_pointer(routes->table[daddr], dev);
 367                dev_hold(dev);
 368                err = 0;
 369        }
 370        mutex_unlock(&routes->lock);
 371        return err;
 372}
 373
 374int phonet_route_del(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
 379        daddr = daddr >> 2;
 380        mutex_lock(&routes->lock);
 381        if (rcu_access_pointer(routes->table[daddr]) == dev)
 382                RCU_INIT_POINTER(routes->table[daddr], NULL);
 383        else
 384                dev = NULL;
 385        mutex_unlock(&routes->lock);
 386
 387        if (!dev)
 388                return -ENOENT;
 389        synchronize_rcu();
 390        dev_put(dev);
 391        return 0;
 392}
 393
 394struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
 395{
 396        struct phonet_net *pnn = phonet_pernet(net);
 397        struct phonet_routes *routes = &pnn->routes;
 398        struct net_device *dev;
 399
 400        daddr >>= 2;
 401        dev = rcu_dereference(routes->table[daddr]);
 402        return dev;
 403}
 404
 405struct net_device *phonet_route_output(struct net *net, u8 daddr)
 406{
 407        struct phonet_net *pnn = phonet_pernet(net);
 408        struct phonet_routes *routes = &pnn->routes;
 409        struct net_device *dev;
 410
 411        daddr >>= 2;
 412        rcu_read_lock();
 413        dev = rcu_dereference(routes->table[daddr]);
 414        if (dev)
 415                dev_hold(dev);
 416        rcu_read_unlock();
 417
 418        if (!dev)
 419                dev = phonet_device_get(net); /* Default route */
 420        return dev;
 421}
 422