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 <net/sock.h>
  31 #include <net/phonet/pn_dev.h>
  32
  33 /* when accessing, remember to lock with spin_lock(&pndevs.lock); */
  34 struct phonet_device_list pndevs = {
  35         .list = LIST_HEAD_INIT(pndevs.list),
  36         .lock = __SPIN_LOCK_UNLOCKED(pndevs.lock),
  37 };
  38
  39 /* Allocate new Phonet device. */
  40 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
  41 {
  42         struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
  43         if (pnd == NULL)
  44                 return NULL;
  45         pnd->netdev = dev;
  46         bitmap_zero(pnd->addrs, 64);
  47
  48         list_add(&pnd->list, &pndevs.list);
  49         return pnd;
  50 }
  51
  52 static struct phonet_device *__phonet_get(struct net_device *dev)
  53 {
  54         struct phonet_device *pnd;
  55
  56         list_for_each_entry(pnd, &pndevs.list, list) {
  57                 if (pnd->netdev == dev)
  58                         return pnd;
  59         }
  60         return NULL;
  61 }
  62
  63 static void __phonet_device_free(struct phonet_device *pnd)
  64 {
  65         list_del(&pnd->list);
  66         kfree(pnd);
  67 }
  68
  69 struct net_device *phonet_device_get(struct net *net)
  70 {
  71         struct phonet_device *pnd;
  72         struct net_device *dev;
  73
  74         spin_lock_bh(&pndevs.lock);
  75         list_for_each_entry(pnd, &pndevs.list, list) {
  76                 dev = pnd->netdev;
  77                 BUG_ON(!dev);
  78
  79                 if (net_eq(dev_net(dev), net) &&
  80                         (dev->reg_state == NETREG_REGISTERED) &&
  81                         ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
  82                         break;
  83                 dev = NULL;
  84         }
  85         if (dev)
  86                 dev_hold(dev);
  87         spin_unlock_bh(&pndevs.lock);
  88         return dev;
  89 }
  90
  91 int phonet_address_add(struct net_device *dev, u8 addr)
  92 {
  93         struct phonet_device *pnd;
  94         int err = 0;
  95
  96         spin_lock_bh(&pndevs.lock);
  97         /* Find or create Phonet-specific device data */
  98         pnd = __phonet_get(dev);
  99         if (pnd == NULL)
 100                 pnd = __phonet_device_alloc(dev);
 101         if (unlikely(pnd == NULL))
 102                 err = -ENOMEM;
 103         else if (test_and_set_bit(addr >> 2, pnd->addrs))
 104                 err = -EEXIST;
 105         spin_unlock_bh(&pndevs.lock);
 106         return err;
 107 }
 108
 109 int phonet_address_del(struct net_device *dev, u8 addr)
 110 {
 111         struct phonet_device *pnd;
 112         int err = 0;
 113
 114         spin_lock_bh(&pndevs.lock);
 115         pnd = __phonet_get(dev);
 116         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs))
 117                 err = -EADDRNOTAVAIL;
 118         else if (bitmap_empty(pnd->addrs, 64))
 119                 __phonet_device_free(pnd);
 120         spin_unlock_bh(&pndevs.lock);
 121         return err;
 122 }
 123
 124 /* Gets a source address toward a destination, through a interface. */
 125 u8 phonet_address_get(struct net_device *dev, u8 addr)
 126 {
 127         struct phonet_device *pnd;
 128
 129         spin_lock_bh(&pndevs.lock);
 130         pnd = __phonet_get(dev);
 131         if (pnd) {
 132                 BUG_ON(bitmap_empty(pnd->addrs, 64));
 133
 134                 /* Use same source address as destination, if possible */
 135                 if (!test_bit(addr >> 2, pnd->addrs))
 136                         addr = find_first_bit(pnd->addrs, 64) << 2;
 137         } else
 138                 addr = PN_NO_ADDR;
 139         spin_unlock_bh(&pndevs.lock);
 140         return addr;
 141 }
 142
 143 int phonet_address_lookup(struct net *net, u8 addr)
 144 {
 145         struct phonet_device *pnd;
 146
 147         spin_lock_bh(&pndevs.lock);
 148         list_for_each_entry(pnd, &pndevs.list, list) {
 149                 if (!net_eq(dev_net(pnd->netdev), net))
 150                         continue;
 151                 /* Don't allow unregistering devices! */
 152                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
 153                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
 154                         continue;
 155
 156                 if (test_bit(addr >> 2, pnd->addrs)) {
 157                         spin_unlock_bh(&pndevs.lock);
 158                         return 0;
 159                 }
 160         }
 161         spin_unlock_bh(&pndevs.lock);
 162         return -EADDRNOTAVAIL;
 163 }
 164
 165 /* notify Phonet of device events */
 166 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
 167                                 void *arg)
 168 {
 169         struct net_device *dev = arg;
 170
 171         if (what == NETDEV_UNREGISTER) {
 172                 struct phonet_device *pnd;
 173
 174                 /* Destroy phonet-specific device data */
 175                 spin_lock_bh(&pndevs.lock);
 176                 pnd = __phonet_get(dev);
 177                 if (pnd)
 178                         __phonet_device_free(pnd);
 179                 spin_unlock_bh(&pndevs.lock);
 180         }
 181         return 0;
 182
 183 }
 184
 185 static struct notifier_block phonet_device_notifier = {
 186         .notifier_call = phonet_device_notify,
 187         .priority = 0,
 188 };
 189
 190 /* Initialize Phonet devices list */
 191 void phonet_device_init(void)
 192 {
 193         register_netdevice_notifier(&phonet_device_notifier);
 194 }
 195
 196 void phonet_device_exit(void)
 197 {
 198         struct phonet_device *pnd, *n;
 199
 200         rtnl_unregister_all(PF_PHONET);
 201         rtnl_lock();
 202         spin_lock_bh(&pndevs.lock);
 203
 204         list_for_each_entry_safe(pnd, n, &pndevs.list, list)
 205                 __phonet_device_free(pnd);
 206
 207         spin_unlock_bh(&pndevs.lock);
 208         rtnl_unlock();
 209         unregister_netdevice_notifier(&phonet_device_notifier);
 210 }