drivers/staging/batman-adv/device.c

   1 /*
   2  * Copyright (C) 2007-2010 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 <linux/device.h>
  23 #include <linux/slab.h>
  24 #include "main.h"
  25 #include "device.h"
  26 #include "send.h"
  27 #include "types.h"
  28 #include "hash.h"
  29 #include "hard-interface.h"
  30
  31 static struct class *batman_class;
  32
  33 static int Major;       /* Major number assigned to our device driver */
  34
  35 static const struct file_operations fops = {
  36         .open = bat_device_open,
  37         .release = bat_device_release,
  38         .read = bat_device_read,
  39         .write = bat_device_write,
  40         .poll = bat_device_poll,
  41 };
  42
  43 static struct device_client *device_client_hash[256];
  44
  45 void bat_device_init(void)
  46 {
  47         memset(device_client_hash, 0, sizeof(device_client_hash));
  48 }
  49
  50 int bat_device_setup(void)
  51 {
  52         int tmp_major;
  53
  54         if (Major)
  55                 return 1;
  56
  57         /* register our device - kernel assigns a free major number */
  58         tmp_major = register_chrdev(0, DRIVER_DEVICE, &fops);
  59         if (tmp_major < 0) {
  60                 printk(KERN_ERR "batman-adv:Registering the character device failed with %d\n",
  61                           tmp_major);
  62                 return 0;
  63         }
  64
  65         batman_class = class_create(THIS_MODULE, "batman-adv");
  66
  67         if (IS_ERR(batman_class)) {
  68                 printk(KERN_ERR "batman-adv:Could not register class 'batman-adv'\n");
  69                 return 0;
  70         }
  71
  72         device_create(batman_class, NULL, MKDEV(tmp_major, 0), NULL,
  73                       "batman-adv");
  74
  75         Major = tmp_major;
  76         return 1;
  77 }
  78
  79 void bat_device_destroy(void)
  80 {
  81         if (!Major)
  82                 return;
  83
  84         device_destroy(batman_class, MKDEV(Major, 0));
  85         class_destroy(batman_class);
  86
  87         /* Unregister the device */
  88         unregister_chrdev(Major, DRIVER_DEVICE);
  89
  90         Major = 0;
  91 }
  92
  93 int bat_device_open(struct inode *inode, struct file *file)
  94 {
  95         unsigned int i;
  96         struct device_client *device_client;
  97
  98         device_client = kmalloc(sizeof(struct device_client), GFP_KERNEL);
  99
 100         if (!device_client)
 101                 return -ENOMEM;
 102
 103         for (i = 0; i < ARRAY_SIZE(device_client_hash); i++) {
 104                 if (!device_client_hash[i]) {
 105                         device_client_hash[i] = device_client;
 106                         break;
 107                 }
 108         }
 109
 110         if (i == ARRAY_SIZE(device_client_hash)) {
 111                 printk(KERN_ERR "batman-adv:Error - can't add another packet client: maximum number of clients reached\n");
 112                 kfree(device_client);
 113                 return -EXFULL;
 114         }
 115
 116         INIT_LIST_HEAD(&device_client->queue_list);
 117         device_client->queue_len = 0;
 118         device_client->index = i;
 119         spin_lock_init(&device_client->lock);
 120         init_waitqueue_head(&device_client->queue_wait);
 121
 122         file->private_data = device_client;
 123
 124         inc_module_count();
 125         return 0;
 126 }
 127
 128 int bat_device_release(struct inode *inode, struct file *file)
 129 {
 130         struct device_client *device_client =
 131                 (struct device_client *)file->private_data;
 132         struct device_packet *device_packet;
 133         struct list_head *list_pos, *list_pos_tmp;
 134         unsigned long flags;
 135
 136         spin_lock_irqsave(&device_client->lock, flags);
 137
 138         /* for all packets in the queue ... */
 139         list_for_each_safe(list_pos, list_pos_tmp, &device_client->queue_list) {
 140                 device_packet = list_entry(list_pos,
 141                                            struct device_packet, list);
 142
 143                 list_del(list_pos);
 144                 kfree(device_packet);
 145         }
 146
 147         device_client_hash[device_client->index] = NULL;
 148         spin_unlock_irqrestore(&device_client->lock, flags);
 149
 150         kfree(device_client);
 151         dec_module_count();
 152
 153         return 0;
 154 }
 155
 156 ssize_t bat_device_read(struct file *file, char __user *buf, size_t count,
 157                         loff_t *ppos)
 158 {
 159         struct device_client *device_client =
 160                 (struct device_client *)file->private_data;
 161         struct device_packet *device_packet;
 162         int error;
 163         unsigned long flags;
 164
 165         if ((file->f_flags & O_NONBLOCK) && (device_client->queue_len == 0))
 166                 return -EAGAIN;
 167
 168         if ((!buf) || (count < sizeof(struct icmp_packet)))
 169                 return -EINVAL;
 170
 171         if (!access_ok(VERIFY_WRITE, buf, count))
 172                 return -EFAULT;
 173
 174         error = wait_event_interruptible(device_client->queue_wait,
 175                                          device_client->queue_len);
 176
 177         if (error)
 178                 return error;
 179
 180         spin_lock_irqsave(&device_client->lock, flags);
 181
 182         device_packet = list_first_entry(&device_client->queue_list,
 183                                          struct device_packet, list);
 184         list_del(&device_packet->list);
 185         device_client->queue_len--;
 186
 187         spin_unlock_irqrestore(&device_client->lock, flags);
 188
 189         error = __copy_to_user(buf, &device_packet->icmp_packet,
 190                                sizeof(struct icmp_packet));
 191
 192         kfree(device_packet);
 193
 194         if (error)
 195                 return error;
 196
 197         return sizeof(struct icmp_packet);
 198 }
 199
 200 ssize_t bat_device_write(struct file *file, const char __user *buff,
 201                          size_t len, loff_t *off)
 202 {
 203         struct device_client *device_client =
 204                 (struct device_client *)file->private_data;
 205         struct icmp_packet icmp_packet;
 206         struct orig_node *orig_node;
 207         struct batman_if *batman_if;
 208         uint8_t dstaddr[ETH_ALEN];
 209         unsigned long flags;
 210
 211         if (len < sizeof(struct icmp_packet)) {
 212                 bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: invalid packet size\n");
 213                 return -EINVAL;
 214         }
 215
 216         if (!access_ok(VERIFY_READ, buff, sizeof(struct icmp_packet)))
 217                 return -EFAULT;
 218
 219         if (__copy_from_user(&icmp_packet, buff, sizeof(icmp_packet)))
 220                 return -EFAULT;
 221
 222         if (icmp_packet.packet_type != BAT_ICMP) {
 223                 bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 224                 return -EINVAL;
 225         }
 226
 227         if (icmp_packet.msg_type != ECHO_REQUEST) {
 228                 bat_dbg(DBG_BATMAN, "batman-adv:Error - can't send packet from char device: got bogus message type (expected: ECHO_REQUEST)\n");
 229                 return -EINVAL;
 230         }
 231
 232         icmp_packet.uid = device_client->index;
 233
 234         if (icmp_packet.version != COMPAT_VERSION) {
 235                 icmp_packet.msg_type = PARAMETER_PROBLEM;
 236                 icmp_packet.ttl = COMPAT_VERSION;
 237                 bat_device_add_packet(device_client, &icmp_packet);
 238                 goto out;
 239         }
 240
 241         if (atomic_read(&module_state) != MODULE_ACTIVE)
 242                 goto dst_unreach;
 243
 244         spin_lock_irqsave(&orig_hash_lock, flags);
 245         orig_node = ((struct orig_node *)hash_find(orig_hash, icmp_packet.dst));
 246
 247         if (!orig_node)
 248                 goto unlock;
 249
 250         if (!orig_node->router)
 251                 goto unlock;
 252
 253         batman_if = orig_node->batman_if;
 254         memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
 255
 256         spin_unlock_irqrestore(&orig_hash_lock, flags);
 257
 258         if (!batman_if)
 259                 goto dst_unreach;
 260
 261         if (batman_if->if_active != IF_ACTIVE)
 262                 goto dst_unreach;
 263
 264         memcpy(icmp_packet.orig,
 265                batman_if->net_dev->dev_addr,
 266                ETH_ALEN);
 267
 268         send_raw_packet((unsigned char *)&icmp_packet,
 269                         sizeof(struct icmp_packet),
 270                         batman_if, dstaddr);
 271
 272         goto out;
 273
 274 unlock:
 275         spin_unlock_irqrestore(&orig_hash_lock, flags);
 276 dst_unreach:
 277         icmp_packet.msg_type = DESTINATION_UNREACHABLE;
 278         bat_device_add_packet(device_client, &icmp_packet);
 279 out:
 280         return len;
 281 }
 282
 283 unsigned int bat_device_poll(struct file *file, poll_table *wait)
 284 {
 285         struct device_client *device_client =
 286                 (struct device_client *)file->private_data;
 287
 288         poll_wait(file, &device_client->queue_wait, wait);
 289
 290         if (device_client->queue_len > 0)
 291                 return POLLIN | POLLRDNORM;
 292
 293         return 0;
 294 }
 295
 296 void bat_device_add_packet(struct device_client *device_client,
 297                            struct icmp_packet *icmp_packet)
 298 {
 299         struct device_packet *device_packet;
 300         unsigned long flags;
 301
 302         device_packet = kmalloc(sizeof(struct device_packet), GFP_KERNEL);
 303
 304         if (!device_packet)
 305                 return;
 306
 307         INIT_LIST_HEAD(&device_packet->list);
 308         memcpy(&device_packet->icmp_packet, icmp_packet,
 309                sizeof(struct icmp_packet));
 310
 311         spin_lock_irqsave(&device_client->lock, flags);
 312
 313         /* while waiting for the lock the device_client could have been
 314          * deleted */
 315         if (!device_client_hash[icmp_packet->uid]) {
 316                 spin_unlock_irqrestore(&device_client->lock, flags);
 317                 kfree(device_packet);
 318                 return;
 319         }
 320
 321         list_add_tail(&device_packet->list, &device_client->queue_list);
 322         device_client->queue_len++;
 323
 324         if (device_client->queue_len > 100) {
 325                 device_packet = list_first_entry(&device_client->queue_list,
 326                                                  struct device_packet, list);
 327
 328                 list_del(&device_packet->list);
 329                 kfree(device_packet);
 330                 device_client->queue_len--;
 331         }
 332
 333         spin_unlock_irqrestore(&device_client->lock, flags);
 334
 335         wake_up(&device_client->queue_wait);
 336 }
 337
 338 void bat_device_receive_packet(struct icmp_packet *icmp_packet)
 339 {
 340         struct device_client *hash = device_client_hash[icmp_packet->uid];
 341
 342         if (hash)
 343                 bat_device_add_packet(hash, icmp_packet);
 344 }