drivers/staging/batman-adv/device.c

   1 /*
   2  * Copyright (C) 2007-2009 B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA
  19  *
  20  */
  21
  22 #include "main.h"
  23 #include "device.h"
  24 #include "send.h"
  25 #include "types.h"
  26 #include "hash.h"
  27
  28 #include "compat.h"
  29
  30 static struct class *batman_class;
  31
  32 static int Major;       /* Major number assigned to our device driver */
  33
  34 static const struct file_operations fops = {
  35         .open = bat_device_open,
  36         .release = bat_device_release,
  37         .read = bat_device_read,
  38         .write = bat_device_write,
  39         .poll = bat_device_poll,
  40 };
  41
  42 static struct device_client *device_client_hash[256];
  43
  44 void bat_device_init(void)
  45 {
  46         int i;
  47
  48         for (i = 0; i < 256; i++)
  49                 device_client_hash[i] = NULL;
  50 }
  51
  52 int bat_device_setup(void)
  53 {
  54         int tmp_major;
  55
  56         if (Major)
  57                 return 1;
  58
  59         /* register our device - kernel assigns a free major number */
  60         tmp_major = register_chrdev(0, DRIVER_DEVICE, &fops);
  61         if (tmp_major < 0) {
  62                 printk(KERN_ERR "batman-adv:Registering the character device failed with %d\n",
  63                           tmp_major);
  64                 return 0;
  65         }
  66
  67         batman_class = class_create(THIS_MODULE, "batman-adv");
  68
  69         if (IS_ERR(batman_class)) {
  70                 printk(KERN_ERR "batman-adv:Could not register class 'batman-adv' \n");
  71                 return 0;
  72         }
  73
  74         device_create(batman_class, NULL, MKDEV(tmp_major, 0), NULL,
  75                       "batman-adv");
  76
  77         Major = tmp_major;
  78         return 1;
  79 }
  80
  81 void bat_device_destroy(void)
  82 {
  83         if (!Major)
  84                 return;
  85
  86         device_destroy(batman_class, MKDEV(Major, 0));
  87         class_destroy(batman_class);
  88
  89         /* Unregister the device */
  90         unregister_chrdev(Major, DRIVER_DEVICE);
  91
  92         Major = 0;
  93 }
  94
  95 int bat_device_open(struct inode *inode, struct file *file)
  96 {
  97         unsigned int i;
  98         struct device_client *device_client;
  99
 100         device_client = kmalloc(sizeof(struct device_client), GFP_KERNEL);
 101
 102         if (!device_client)
 103                 return -ENOMEM;
 104
 105         for (i = 0; i < 256; i++) {
 106                 if (!device_client_hash[i]) {
 107                         device_client_hash[i] = device_client;
 108                         break;
 109                 }
 110         }
 111
 112         if (device_client_hash[i] != device_client) {
 113                 printk(KERN_ERR "batman-adv:Error - can't add another packet client: maximum number of clients reached \n");
 114                 kfree(device_client);
 115                 return -EXFULL;
 116         }
 117
 118         INIT_LIST_HEAD(&device_client->queue_list);
 119         device_client->queue_len = 0;
 120         device_client->index = i;
 121         device_client->lock = __SPIN_LOCK_UNLOCKED(device_client->lock);
 122         init_waitqueue_head(&device_client->queue_wait);
 123
 124         file->private_data = device_client;
 125
 126         inc_module_count();
 127         return 0;
 128 }
 129
 130 int bat_device_release(struct inode *inode, struct file *file)
 131 {
 132         struct device_client *device_client =
 133                 (struct device_client *)file->private_data;
 134         struct device_packet *device_packet;
 135         struct list_head *list_pos, *list_pos_tmp;
 136         unsigned long flags;
 137
 138         spin_lock_irqsave(&device_client->lock, flags);
 139
 140         /* for all packets in the queue ... */
 141         list_for_each_safe(list_pos, list_pos_tmp, &device_client->queue_list) {
 142                 device_packet = list_entry(list_pos,
 143                                            struct device_packet, list);
 144
 145                 list_del(list_pos);
 146                 kfree(device_packet);
 147         }
 148
 149         device_client_hash[device_client->index] = NULL;
 150         spin_unlock_irqrestore(&device_client->lock, flags);
 151
 152         kfree(device_client);
 153         dec_module_count();
 154
 155         return 0;
 156 }
 157
 158 ssize_t bat_device_read(struct file *file, char __user *buf, size_t count,
 159                         loff_t *ppos)
 160 {
 161         struct device_client *device_client =
 162                 (struct device_client *)file->private_data;
 163         struct device_packet *device_packet;
 164         int error;
 165         unsigned long flags;
 166
 167         if ((file->f_flags & O_NONBLOCK) && (device_client->queue_len == 0))
 168                 return -EAGAIN;
 169
 170         if ((!buf) || (count < sizeof(struct icmp_packet)))
 171                 return -EINVAL;
 172
 173         if (!access_ok(VERIFY_WRITE, buf, count))
 174                 return -EFAULT;
 175
 176         error = wait_event_interruptible(device_client->queue_wait,
 177                                          device_client->queue_len);
 178
 179         if (error)
 180                 return error;
 181
 182         spin_lock_irqsave(&device_client->lock, flags);
 183
 184         device_packet = list_first_entry(&device_client->queue_list,
 185                                          struct device_packet, list);
 186         list_del(&device_packet->list);
 187         device_client->queue_len--;
 188
 189         spin_unlock_irqrestore(&device_client->lock, flags);
 190
 191         error = __copy_to_user(buf, &device_packet->icmp_packet,
 192                                sizeof(struct icmp_packet));
 193
 194         kfree(device_packet);
 195
 196         if (error)
 197                 return error;
 198
 199         return sizeof(struct icmp_packet);
 200 }
 201
 202 ssize_t bat_device_write(struct file *file, const char __user *buff,
 203                          size_t len, loff_t *off)
 204 {
 205         struct device_client *device_client =
 206                 (struct device_client *)file->private_data;
 207         struct icmp_packet icmp_packet;
 208         struct orig_node *orig_node;
 209         struct batman_if *batman_if;
 210         unsigned long flags;
 211
 212         if (len < sizeof(struct icmp_packet)) {
 213                 bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: invalid packet size\n");
 214                 return -EINVAL;
 215         }
 216
 217         if (!access_ok(VERIFY_READ, buff, sizeof(struct icmp_packet)))
 218                 return -EFAULT;
 219
 220         if (__copy_from_user(&icmp_packet, buff, sizeof(icmp_packet)))
 221                 return -EFAULT;
 222
 223         if (icmp_packet.packet_type != BAT_ICMP) {
 224                 bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 225                 return -EINVAL;
 226         }
 227
 228         if (icmp_packet.msg_type != ECHO_REQUEST) {
 229                 bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: got bogus message type (expected: ECHO_REQUEST)\n");
 230                 return -EINVAL;
 231         }
 232
 233         icmp_packet.uid = device_client->index;
 234
 235         if (icmp_packet.version != COMPAT_VERSION) {
 236                 icmp_packet.msg_type = PARAMETER_PROBLEM;
 237                 icmp_packet.ttl = COMPAT_VERSION;
 238                 bat_device_add_packet(device_client, &icmp_packet);
 239                 goto out;
 240         }
 241
 242         if (atomic_read(&module_state) != MODULE_ACTIVE)
 243                 goto dst_unreach;
 244
 245         spin_lock_irqsave(&orig_hash_lock, flags);
 246         orig_node = ((struct orig_node *)hash_find(orig_hash, icmp_packet.dst));
 247
 248         if (!orig_node)
 249                 goto unlock;
 250
 251         if (!orig_node->router)
 252                 goto unlock;
 253
 254         batman_if = orig_node->batman_if;
 255
 256         if (!batman_if)
 257                 goto unlock;
 258
 259         memcpy(icmp_packet.orig,
 260                batman_if->net_dev->dev_addr,
 261                ETH_ALEN);
 262
 263         send_raw_packet((unsigned char *)&icmp_packet,
 264                         sizeof(struct icmp_packet),
 265                         batman_if, orig_node->router->addr);
 266
 267         spin_unlock_irqrestore(&orig_hash_lock, flags);
 268         goto out;
 269
 270 unlock:
 271         spin_unlock_irqrestore(&orig_hash_lock, flags);
 272 dst_unreach:
 273         icmp_packet.msg_type = DESTINATION_UNREACHABLE;
 274         bat_device_add_packet(device_client, &icmp_packet);
 275 out:
 276         return len;
 277 }
 278
 279 unsigned int bat_device_poll(struct file *file, poll_table *wait)
 280 {
 281         struct device_client *device_client =
 282                 (struct device_client *)file->private_data;
 283
 284         poll_wait(file, &device_client->queue_wait, wait);
 285
 286         if (device_client->queue_len > 0)
 287                 return POLLIN | POLLRDNORM;
 288
 289         return 0;
 290 }
 291
 292 void bat_device_add_packet(struct device_client *device_client,
 293                            struct icmp_packet *icmp_packet)
 294 {
 295         struct device_packet *device_packet;
 296         unsigned long flags;
 297
 298         device_packet = kmalloc(sizeof(struct device_packet), GFP_KERNEL);
 299
 300         if (!device_packet)
 301                 return;
 302
 303         INIT_LIST_HEAD(&device_packet->list);
 304         memcpy(&device_packet->icmp_packet, icmp_packet,
 305                sizeof(struct icmp_packet));
 306
 307         spin_lock_irqsave(&device_client->lock, flags);
 308
 309         /* while waiting for the lock the device_client could have been
 310          * deleted */
 311         if (!device_client_hash[icmp_packet->uid]) {
 312                 spin_unlock_irqrestore(&device_client->lock, flags);
 313                 kfree(device_packet);
 314                 return;
 315         }
 316
 317         list_add_tail(&device_packet->list, &device_client->queue_list);
 318         device_client->queue_len++;
 319
 320         if (device_client->queue_len > 100) {
 321                 device_packet = list_first_entry(&device_client->queue_list,
 322                                                  struct device_packet, list);
 323
 324                 list_del(&device_packet->list);
 325                 kfree(device_packet);
 326                 device_client->queue_len--;
 327         }
 328
 329         spin_unlock_irqrestore(&device_client->lock, flags);
 330
 331         wake_up(&device_client->queue_wait);
 332 }
 333
 334 void bat_device_receive_packet(struct icmp_packet *icmp_packet)
 335 {
 336         struct device_client *hash = device_client_hash[icmp_packet->uid];
 337
 338         if (hash)
 339                 bat_device_add_packet(hash, icmp_packet);
 340 }