net/batman-adv/icmp_socket.c

   1 /* Copyright (C) 2007-2013 B.A.T.M.A.N. contributors:
   2  *
   3  * Marek Lindner
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include "main.h"
  21 #include <linux/debugfs.h>
  22 #include <linux/slab.h>
  23 #include "icmp_socket.h"
  24 #include "send.h"
  25 #include "hash.h"
  26 #include "originator.h"
  27 #include "hard-interface.h"
  28
  29 static struct batadv_socket_client *batadv_socket_client_hash[256];
  30
  31 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  32                                      struct batadv_icmp_header *icmph,
  33                                      size_t icmp_len);
  34
  35 void batadv_socket_init(void)
  36 {
  37         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  38 }
  39
  40 static int batadv_socket_open(struct inode *inode, struct file *file)
  41 {
  42         unsigned int i;
  43         struct batadv_socket_client *socket_client;
  44
  45         if (!try_module_get(THIS_MODULE))
  46                 return -EBUSY;
  47
  48         nonseekable_open(inode, file);
  49
  50         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  51         if (!socket_client) {
  52                 module_put(THIS_MODULE);
  53                 return -ENOMEM;
  54         }
  55
  56         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  57                 if (!batadv_socket_client_hash[i]) {
  58                         batadv_socket_client_hash[i] = socket_client;
  59                         break;
  60                 }
  61         }
  62
  63         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  64                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  65                 kfree(socket_client);
  66                 module_put(THIS_MODULE);
  67                 return -EXFULL;
  68         }
  69
  70         INIT_LIST_HEAD(&socket_client->queue_list);
  71         socket_client->queue_len = 0;
  72         socket_client->index = i;
  73         socket_client->bat_priv = inode->i_private;
  74         spin_lock_init(&socket_client->lock);
  75         init_waitqueue_head(&socket_client->queue_wait);
  76
  77         file->private_data = socket_client;
  78
  79         return 0;
  80 }
  81
  82 static int batadv_socket_release(struct inode *inode, struct file *file)
  83 {
  84         struct batadv_socket_client *socket_client = file->private_data;
  85         struct batadv_socket_packet *socket_packet;
  86         struct list_head *list_pos, *list_pos_tmp;
  87
  88         spin_lock_bh(&socket_client->lock);
  89
  90         /* for all packets in the queue ... */
  91         list_for_each_safe(list_pos, list_pos_tmp, &socket_client->queue_list) {
  92                 socket_packet = list_entry(list_pos,
  93                                            struct batadv_socket_packet, list);
  94
  95                 list_del(list_pos);
  96                 kfree(socket_packet);
  97         }
  98
  99         batadv_socket_client_hash[socket_client->index] = NULL;
 100         spin_unlock_bh(&socket_client->lock);
 101
 102         kfree(socket_client);
 103         module_put(THIS_MODULE);
 104
 105         return 0;
 106 }
 107
 108 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 109                                   size_t count, loff_t *ppos)
 110 {
 111         struct batadv_socket_client *socket_client = file->private_data;
 112         struct batadv_socket_packet *socket_packet;
 113         size_t packet_len;
 114         int error;
 115
 116         if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
 117                 return -EAGAIN;
 118
 119         if ((!buf) || (count < sizeof(struct batadv_icmp_packet)))
 120                 return -EINVAL;
 121
 122         if (!access_ok(VERIFY_WRITE, buf, count))
 123                 return -EFAULT;
 124
 125         error = wait_event_interruptible(socket_client->queue_wait,
 126                                          socket_client->queue_len);
 127
 128         if (error)
 129                 return error;
 130
 131         spin_lock_bh(&socket_client->lock);
 132
 133         socket_packet = list_first_entry(&socket_client->queue_list,
 134                                          struct batadv_socket_packet, list);
 135         list_del(&socket_packet->list);
 136         socket_client->queue_len--;
 137
 138         spin_unlock_bh(&socket_client->lock);
 139
 140         packet_len = min(count, socket_packet->icmp_len);
 141         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 142
 143         kfree(socket_packet);
 144
 145         if (error)
 146                 return -EFAULT;
 147
 148         return packet_len;
 149 }
 150
 151 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 152                                    size_t len, loff_t *off)
 153 {
 154         struct batadv_socket_client *socket_client = file->private_data;
 155         struct batadv_priv *bat_priv = socket_client->bat_priv;
 156         struct batadv_hard_iface *primary_if = NULL;
 157         struct sk_buff *skb;
 158         struct batadv_icmp_packet_rr *icmp_packet_rr;
 159         struct batadv_icmp_header *icmp_header;
 160         struct batadv_orig_node *orig_node = NULL;
 161         struct batadv_neigh_node *neigh_node = NULL;
 162         size_t packet_len = sizeof(struct batadv_icmp_packet);
 163
 164         if (len < sizeof(struct batadv_icmp_header)) {
 165                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 166                            "Error - can't send packet from char device: invalid packet size\n");
 167                 return -EINVAL;
 168         }
 169
 170         primary_if = batadv_primary_if_get_selected(bat_priv);
 171
 172         if (!primary_if) {
 173                 len = -EFAULT;
 174                 goto out;
 175         }
 176
 177         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 178                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 179         else
 180                 packet_len = len;
 181
 182         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 183         if (!skb) {
 184                 len = -ENOMEM;
 185                 goto out;
 186         }
 187
 188         skb->priority = TC_PRIO_CONTROL;
 189         skb_reserve(skb, ETH_HLEN);
 190         icmp_header = (struct batadv_icmp_header *)skb_put(skb, packet_len);
 191
 192         if (copy_from_user(icmp_header, buff, packet_len)) {
 193                 len = -EFAULT;
 194                 goto free_skb;
 195         }
 196
 197         if (icmp_header->header.packet_type != BATADV_ICMP) {
 198                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 199                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 200                 len = -EINVAL;
 201                 goto free_skb;
 202         }
 203
 204         switch (icmp_header->msg_type) {
 205         case BATADV_ECHO_REQUEST:
 206                 if (len < sizeof(struct batadv_icmp_packet)) {
 207                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 208                                    "Error - can't send packet from char device: invalid packet size\n");
 209                         len = -EINVAL;
 210                         goto free_skb;
 211                 }
 212
 213                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 214                         goto dst_unreach;
 215
 216                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 217                 if (!orig_node)
 218                         goto dst_unreach;
 219
 220                 neigh_node = batadv_orig_node_get_router(orig_node);
 221                 if (!neigh_node)
 222                         goto dst_unreach;
 223
 224                 if (!neigh_node->if_incoming)
 225                         goto dst_unreach;
 226
 227                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 228                         goto dst_unreach;
 229
 230                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 231                 if (packet_len == sizeof(*icmp_packet_rr))
 232                         memcpy(icmp_packet_rr->rr,
 233                                neigh_node->if_incoming->net_dev->dev_addr,
 234                                ETH_ALEN);
 235
 236                 break;
 237         default:
 238                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 239                            "Error - can't send packet from char device: got unknown message type\n");
 240                 len = -EINVAL;
 241                 goto free_skb;
 242         }
 243
 244         icmp_header->uid = socket_client->index;
 245
 246         if (icmp_header->header.version != BATADV_COMPAT_VERSION) {
 247                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 248                 icmp_header->header.version = BATADV_COMPAT_VERSION;
 249                 batadv_socket_add_packet(socket_client, icmp_header,
 250                                          packet_len);
 251                 goto free_skb;
 252         }
 253
 254         memcpy(icmp_header->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 255
 256         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 257         goto out;
 258
 259 dst_unreach:
 260         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 261         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 262 free_skb:
 263         kfree_skb(skb);
 264 out:
 265         if (primary_if)
 266                 batadv_hardif_free_ref(primary_if);
 267         if (neigh_node)
 268                 batadv_neigh_node_free_ref(neigh_node);
 269         if (orig_node)
 270                 batadv_orig_node_free_ref(orig_node);
 271         return len;
 272 }
 273
 274 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 275 {
 276         struct batadv_socket_client *socket_client = file->private_data;
 277
 278         poll_wait(file, &socket_client->queue_wait, wait);
 279
 280         if (socket_client->queue_len > 0)
 281                 return POLLIN | POLLRDNORM;
 282
 283         return 0;
 284 }
 285
 286 static const struct file_operations batadv_fops = {
 287         .owner = THIS_MODULE,
 288         .open = batadv_socket_open,
 289         .release = batadv_socket_release,
 290         .read = batadv_socket_read,
 291         .write = batadv_socket_write,
 292         .poll = batadv_socket_poll,
 293         .llseek = no_llseek,
 294 };
 295
 296 int batadv_socket_setup(struct batadv_priv *bat_priv)
 297 {
 298         struct dentry *d;
 299
 300         if (!bat_priv->debug_dir)
 301                 goto err;
 302
 303         d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 304                                 bat_priv->debug_dir, bat_priv, &batadv_fops);
 305         if (!d)
 306                 goto err;
 307
 308         return 0;
 309
 310 err:
 311         return -ENOMEM;
 312 }
 313
 314 /**
 315  * batadv_socket_receive_packet - schedule an icmp packet to be sent to userspace
 316  *  on an icmp socket.
 317  * @socket_client: the socket this packet belongs to
 318  * @icmph: pointer to the header of the icmp packet
 319  * @icmp_len: total length of the icmp packet
 320  */
 321 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 322                                      struct batadv_icmp_header *icmph,
 323                                      size_t icmp_len)
 324 {
 325         struct batadv_socket_packet *socket_packet;
 326         size_t len;
 327
 328         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 329
 330         if (!socket_packet)
 331                 return;
 332
 333         len = icmp_len;
 334         /* check the maximum length before filling the buffer */
 335         if (len > sizeof(socket_packet->icmp_packet))
 336                 len = sizeof(socket_packet->icmp_packet);
 337
 338         INIT_LIST_HEAD(&socket_packet->list);
 339         memcpy(&socket_packet->icmp_packet, icmph, len);
 340         socket_packet->icmp_len = len;
 341
 342         spin_lock_bh(&socket_client->lock);
 343
 344         /* while waiting for the lock the socket_client could have been
 345          * deleted
 346          */
 347         if (!batadv_socket_client_hash[icmph->uid]) {
 348                 spin_unlock_bh(&socket_client->lock);
 349                 kfree(socket_packet);
 350                 return;
 351         }
 352
 353         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 354         socket_client->queue_len++;
 355
 356         if (socket_client->queue_len > 100) {
 357                 socket_packet = list_first_entry(&socket_client->queue_list,
 358                                                  struct batadv_socket_packet,
 359                                                  list);
 360
 361                 list_del(&socket_packet->list);
 362                 kfree(socket_packet);
 363                 socket_client->queue_len--;
 364         }
 365
 366         spin_unlock_bh(&socket_client->lock);
 367
 368         wake_up(&socket_client->queue_wait);
 369 }
 370
 371 /**
 372  * batadv_socket_receive_packet - schedule an icmp packet to be received
 373  *  locally and sent to userspace.
 374  * @icmph: pointer to the header of the icmp packet
 375  * @icmp_len: total length of the icmp packet
 376  */
 377 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 378                                   size_t icmp_len)
 379 {
 380         struct batadv_socket_client *hash;
 381
 382         hash = batadv_socket_client_hash[icmph->uid];
 383         if (hash)
 384                 batadv_socket_add_packet(hash, icmph, icmp_len);
 385 }