net/batman-adv/icmp_socket.c

   1 /*
   2  * Copyright (C) 2007-2011 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 <linux/debugfs.h>
  24 #include <linux/slab.h>
  25 #include "icmp_socket.h"
  26 #include "send.h"
  27 #include "hash.h"
  28 #include "originator.h"
  29 #include "hard-interface.h"
  30
  31 static struct socket_client *socket_client_hash[256];
  32
  33 static void bat_socket_add_packet(struct socket_client *socket_client,
  34                                   struct icmp_packet_rr *icmp_packet,
  35                                   size_t icmp_len);
  36
  37 void bat_socket_init(void)
  38 {
  39         memset(socket_client_hash, 0, sizeof(socket_client_hash));
  40 }
  41
  42 static int bat_socket_open(struct inode *inode, struct file *file)
  43 {
  44         unsigned int i;
  45         struct socket_client *socket_client;
  46
  47         nonseekable_open(inode, file);
  48
  49         socket_client = kmalloc(sizeof(struct socket_client), GFP_KERNEL);
  50
  51         if (!socket_client)
  52                 return -ENOMEM;
  53
  54         for (i = 0; i < ARRAY_SIZE(socket_client_hash); i++) {
  55                 if (!socket_client_hash[i]) {
  56                         socket_client_hash[i] = socket_client;
  57                         break;
  58                 }
  59         }
  60
  61         if (i == ARRAY_SIZE(socket_client_hash)) {
  62                 pr_err("Error - can't add another packet client: "
  63                        "maximum number of clients reached\n");
  64                 kfree(socket_client);
  65                 return -EXFULL;
  66         }
  67
  68         INIT_LIST_HEAD(&socket_client->queue_list);
  69         socket_client->queue_len = 0;
  70         socket_client->index = i;
  71         socket_client->bat_priv = inode->i_private;
  72         spin_lock_init(&socket_client->lock);
  73         init_waitqueue_head(&socket_client->queue_wait);
  74
  75         file->private_data = socket_client;
  76
  77         inc_module_count();
  78         return 0;
  79 }
  80
  81 static int bat_socket_release(struct inode *inode, struct file *file)
  82 {
  83         struct socket_client *socket_client = file->private_data;
  84         struct socket_packet *socket_packet;
  85         struct list_head *list_pos, *list_pos_tmp;
  86
  87         spin_lock_bh(&socket_client->lock);
  88
  89         /* for all packets in the queue ... */
  90         list_for_each_safe(list_pos, list_pos_tmp, &socket_client->queue_list) {
  91                 socket_packet = list_entry(list_pos,
  92                                            struct socket_packet, list);
  93
  94                 list_del(list_pos);
  95                 kfree(socket_packet);
  96         }
  97
  98         socket_client_hash[socket_client->index] = NULL;
  99         spin_unlock_bh(&socket_client->lock);
 100
 101         kfree(socket_client);
 102         dec_module_count();
 103
 104         return 0;
 105 }
 106
 107 static ssize_t bat_socket_read(struct file *file, char __user *buf,
 108                                size_t count, loff_t *ppos)
 109 {
 110         struct socket_client *socket_client = file->private_data;
 111         struct socket_packet *socket_packet;
 112         size_t packet_len;
 113         int error;
 114
 115         if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
 116                 return -EAGAIN;
 117
 118         if ((!buf) || (count < sizeof(struct icmp_packet)))
 119                 return -EINVAL;
 120
 121         if (!access_ok(VERIFY_WRITE, buf, count))
 122                 return -EFAULT;
 123
 124         error = wait_event_interruptible(socket_client->queue_wait,
 125                                          socket_client->queue_len);
 126
 127         if (error)
 128                 return error;
 129
 130         spin_lock_bh(&socket_client->lock);
 131
 132         socket_packet = list_first_entry(&socket_client->queue_list,
 133                                          struct socket_packet, list);
 134         list_del(&socket_packet->list);
 135         socket_client->queue_len--;
 136
 137         spin_unlock_bh(&socket_client->lock);
 138
 139         error = __copy_to_user(buf, &socket_packet->icmp_packet,
 140                                socket_packet->icmp_len);
 141
 142         packet_len = socket_packet->icmp_len;
 143         kfree(socket_packet);
 144
 145         if (error)
 146                 return -EFAULT;
 147
 148         return packet_len;
 149 }
 150
 151 static ssize_t bat_socket_write(struct file *file, const char __user *buff,
 152                                 size_t len, loff_t *off)
 153 {
 154         struct socket_client *socket_client = file->private_data;
 155         struct bat_priv *bat_priv = socket_client->bat_priv;
 156         struct sk_buff *skb;
 157         struct icmp_packet_rr *icmp_packet;
 158
 159         struct orig_node *orig_node = NULL;
 160         struct neigh_node *neigh_node = NULL;
 161         size_t packet_len = sizeof(struct icmp_packet);
 162
 163         if (len < sizeof(struct icmp_packet)) {
 164                 bat_dbg(DBG_BATMAN, bat_priv,
 165                         "Error - can't send packet from char device: "
 166                         "invalid packet size\n");
 167                 return -EINVAL;
 168         }
 169
 170         if (!bat_priv->primary_if)
 171                 return -EFAULT;
 172
 173         if (len >= sizeof(struct icmp_packet_rr))
 174                 packet_len = sizeof(struct icmp_packet_rr);
 175
 176         skb = dev_alloc_skb(packet_len + sizeof(struct ethhdr));
 177         if (!skb)
 178                 return -ENOMEM;
 179
 180         skb_reserve(skb, sizeof(struct ethhdr));
 181         icmp_packet = (struct icmp_packet_rr *)skb_put(skb, packet_len);
 182
 183         if (!access_ok(VERIFY_READ, buff, packet_len)) {
 184                 len = -EFAULT;
 185                 goto free_skb;
 186         }
 187
 188         if (__copy_from_user(icmp_packet, buff, packet_len)) {
 189                 len = -EFAULT;
 190                 goto free_skb;
 191         }
 192
 193         if (icmp_packet->packet_type != BAT_ICMP) {
 194                 bat_dbg(DBG_BATMAN, bat_priv,
 195                         "Error - can't send packet from char device: "
 196                         "got bogus packet type (expected: BAT_ICMP)\n");
 197                 len = -EINVAL;
 198                 goto free_skb;
 199         }
 200
 201         if (icmp_packet->msg_type != ECHO_REQUEST) {
 202                 bat_dbg(DBG_BATMAN, bat_priv,
 203                         "Error - can't send packet from char device: "
 204                         "got bogus message type (expected: ECHO_REQUEST)\n");
 205                 len = -EINVAL;
 206                 goto free_skb;
 207         }
 208
 209         icmp_packet->uid = socket_client->index;
 210
 211         if (icmp_packet->version != COMPAT_VERSION) {
 212                 icmp_packet->msg_type = PARAMETER_PROBLEM;
 213                 icmp_packet->ttl = COMPAT_VERSION;
 214                 bat_socket_add_packet(socket_client, icmp_packet, packet_len);
 215                 goto free_skb;
 216         }
 217
 218         if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
 219                 goto dst_unreach;
 220
 221         rcu_read_lock();
 222         orig_node = orig_hash_find(bat_priv, icmp_packet->dst);
 223
 224         if (!orig_node)
 225                 goto unlock;
 226
 227         neigh_node = orig_node->router;
 228
 229         if (!neigh_node)
 230                 goto unlock;
 231
 232         if (!atomic_inc_not_zero(&neigh_node->refcount)) {
 233                 neigh_node = NULL;
 234                 goto unlock;
 235         }
 236
 237         rcu_read_unlock();
 238
 239         if (!neigh_node->if_incoming)
 240                 goto dst_unreach;
 241
 242         if (neigh_node->if_incoming->if_status != IF_ACTIVE)
 243                 goto dst_unreach;
 244
 245         memcpy(icmp_packet->orig,
 246                bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 247
 248         if (packet_len == sizeof(struct icmp_packet_rr))
 249                 memcpy(icmp_packet->rr,
 250                        neigh_node->if_incoming->net_dev->dev_addr, ETH_ALEN);
 251
 252         send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 253         goto out;
 254
 255 unlock:
 256         rcu_read_unlock();
 257 dst_unreach:
 258         icmp_packet->msg_type = DESTINATION_UNREACHABLE;
 259         bat_socket_add_packet(socket_client, icmp_packet, packet_len);
 260 free_skb:
 261         kfree_skb(skb);
 262 out:
 263         if (neigh_node)
 264                 neigh_node_free_ref(neigh_node);
 265         if (orig_node)
 266                 orig_node_free_ref(orig_node);
 267         return len;
 268 }
 269
 270 static unsigned int bat_socket_poll(struct file *file, poll_table *wait)
 271 {
 272         struct socket_client *socket_client = file->private_data;
 273
 274         poll_wait(file, &socket_client->queue_wait, wait);
 275
 276         if (socket_client->queue_len > 0)
 277                 return POLLIN | POLLRDNORM;
 278
 279         return 0;
 280 }
 281
 282 static const struct file_operations fops = {
 283         .owner = THIS_MODULE,
 284         .open = bat_socket_open,
 285         .release = bat_socket_release,
 286         .read = bat_socket_read,
 287         .write = bat_socket_write,
 288         .poll = bat_socket_poll,
 289         .llseek = no_llseek,
 290 };
 291
 292 int bat_socket_setup(struct bat_priv *bat_priv)
 293 {
 294         struct dentry *d;
 295
 296         if (!bat_priv->debug_dir)
 297                 goto err;
 298
 299         d = debugfs_create_file(ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 300                                 bat_priv->debug_dir, bat_priv, &fops);
 301         if (d)
 302                 goto err;
 303
 304         return 0;
 305
 306 err:
 307         return 1;
 308 }
 309
 310 static void bat_socket_add_packet(struct socket_client *socket_client,
 311                                   struct icmp_packet_rr *icmp_packet,
 312                                   size_t icmp_len)
 313 {
 314         struct socket_packet *socket_packet;
 315
 316         socket_packet = kmalloc(sizeof(struct socket_packet), GFP_ATOMIC);
 317
 318         if (!socket_packet)
 319                 return;
 320
 321         INIT_LIST_HEAD(&socket_packet->list);
 322         memcpy(&socket_packet->icmp_packet, icmp_packet, icmp_len);
 323         socket_packet->icmp_len = icmp_len;
 324
 325         spin_lock_bh(&socket_client->lock);
 326
 327         /* while waiting for the lock the socket_client could have been
 328          * deleted */
 329         if (!socket_client_hash[icmp_packet->uid]) {
 330                 spin_unlock_bh(&socket_client->lock);
 331                 kfree(socket_packet);
 332                 return;
 333         }
 334
 335         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 336         socket_client->queue_len++;
 337
 338         if (socket_client->queue_len > 100) {
 339                 socket_packet = list_first_entry(&socket_client->queue_list,
 340                                                  struct socket_packet, list);
 341
 342                 list_del(&socket_packet->list);
 343                 kfree(socket_packet);
 344                 socket_client->queue_len--;
 345         }
 346
 347         spin_unlock_bh(&socket_client->lock);
 348
 349         wake_up(&socket_client->queue_wait);
 350 }
 351
 352 void bat_socket_receive_packet(struct icmp_packet_rr *icmp_packet,
 353                                size_t icmp_len)
 354 {
 355         struct socket_client *hash = socket_client_hash[icmp_packet->uid];
 356
 357         if (hash)
 358                 bat_socket_add_packet(hash, icmp_packet, icmp_len);
 359 }