net/batman-adv/icmp_socket.c

   1 /* Copyright (C) 2007-2014 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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "main.h"
  19 #include <linux/debugfs.h>
  20 #include <linux/slab.h>
  21 #include "icmp_socket.h"
  22 #include "send.h"
  23 #include "hash.h"
  24 #include "originator.h"
  25 #include "hard-interface.h"
  26
  27 static struct batadv_socket_client *batadv_socket_client_hash[256];
  28
  29 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  30                                      struct batadv_icmp_header *icmph,
  31                                      size_t icmp_len);
  32
  33 void batadv_socket_init(void)
  34 {
  35         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  36 }
  37
  38 static int batadv_socket_open(struct inode *inode, struct file *file)
  39 {
  40         unsigned int i;
  41         struct batadv_socket_client *socket_client;
  42
  43         if (!try_module_get(THIS_MODULE))
  44                 return -EBUSY;
  45
  46         nonseekable_open(inode, file);
  47
  48         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  49         if (!socket_client) {
  50                 module_put(THIS_MODULE);
  51                 return -ENOMEM;
  52         }
  53
  54         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  55                 if (!batadv_socket_client_hash[i]) {
  56                         batadv_socket_client_hash[i] = socket_client;
  57                         break;
  58                 }
  59         }
  60
  61         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  62                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  63                 kfree(socket_client);
  64                 module_put(THIS_MODULE);
  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         return 0;
  78 }
  79
  80 static int batadv_socket_release(struct inode *inode, struct file *file)
  81 {
  82         struct batadv_socket_client *socket_client = file->private_data;
  83         struct batadv_socket_packet *socket_packet;
  84         struct list_head *list_pos, *list_pos_tmp;
  85
  86         spin_lock_bh(&socket_client->lock);
  87
  88         /* for all packets in the queue ... */
  89         list_for_each_safe(list_pos, list_pos_tmp, &socket_client->queue_list) {
  90                 socket_packet = list_entry(list_pos,
  91                                            struct batadv_socket_packet, list);
  92
  93                 list_del(list_pos);
  94                 kfree(socket_packet);
  95         }
  96
  97         batadv_socket_client_hash[socket_client->index] = NULL;
  98         spin_unlock_bh(&socket_client->lock);
  99
 100         kfree(socket_client);
 101         module_put(THIS_MODULE);
 102
 103         return 0;
 104 }
 105
 106 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 107                                   size_t count, loff_t *ppos)
 108 {
 109         struct batadv_socket_client *socket_client = file->private_data;
 110         struct batadv_socket_packet *socket_packet;
 111         size_t packet_len;
 112         int error;
 113
 114         if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
 115                 return -EAGAIN;
 116
 117         if ((!buf) || (count < sizeof(struct batadv_icmp_packet)))
 118                 return -EINVAL;
 119
 120         if (!access_ok(VERIFY_WRITE, buf, count))
 121                 return -EFAULT;
 122
 123         error = wait_event_interruptible(socket_client->queue_wait,
 124                                          socket_client->queue_len);
 125
 126         if (error)
 127                 return error;
 128
 129         spin_lock_bh(&socket_client->lock);
 130
 131         socket_packet = list_first_entry(&socket_client->queue_list,
 132                                          struct batadv_socket_packet, list);
 133         list_del(&socket_packet->list);
 134         socket_client->queue_len--;
 135
 136         spin_unlock_bh(&socket_client->lock);
 137
 138         packet_len = min(count, socket_packet->icmp_len);
 139         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 140
 141         kfree(socket_packet);
 142
 143         if (error)
 144                 return -EFAULT;
 145
 146         return packet_len;
 147 }
 148
 149 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 150                                    size_t len, loff_t *off)
 151 {
 152         struct batadv_socket_client *socket_client = file->private_data;
 153         struct batadv_priv *bat_priv = socket_client->bat_priv;
 154         struct batadv_hard_iface *primary_if = NULL;
 155         struct sk_buff *skb;
 156         struct batadv_icmp_packet_rr *icmp_packet_rr;
 157         struct batadv_icmp_header *icmp_header;
 158         struct batadv_orig_node *orig_node = NULL;
 159         struct batadv_neigh_node *neigh_node = NULL;
 160         size_t packet_len = sizeof(struct batadv_icmp_packet);
 161         uint8_t *addr;
 162
 163         if (len < sizeof(struct batadv_icmp_header)) {
 164                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 165                            "Error - can't send packet from char device: invalid packet size\n");
 166                 return -EINVAL;
 167         }
 168
 169         primary_if = batadv_primary_if_get_selected(bat_priv);
 170
 171         if (!primary_if) {
 172                 len = -EFAULT;
 173                 goto out;
 174         }
 175
 176         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 177                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 178         else
 179                 packet_len = len;
 180
 181         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 182         if (!skb) {
 183                 len = -ENOMEM;
 184                 goto out;
 185         }
 186
 187         skb->priority = TC_PRIO_CONTROL;
 188         skb_reserve(skb, ETH_HLEN);
 189         icmp_header = (struct batadv_icmp_header *)skb_put(skb, packet_len);
 190
 191         if (copy_from_user(icmp_header, buff, packet_len)) {
 192                 len = -EFAULT;
 193                 goto free_skb;
 194         }
 195
 196         if (icmp_header->packet_type != BATADV_ICMP) {
 197                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 198                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 199                 len = -EINVAL;
 200                 goto free_skb;
 201         }
 202
 203         switch (icmp_header->msg_type) {
 204         case BATADV_ECHO_REQUEST:
 205                 if (len < sizeof(struct batadv_icmp_packet)) {
 206                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 207                                    "Error - can't send packet from char device: invalid packet size\n");
 208                         len = -EINVAL;
 209                         goto free_skb;
 210                 }
 211
 212                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 213                         goto dst_unreach;
 214
 215                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 216                 if (!orig_node)
 217                         goto dst_unreach;
 218
 219                 neigh_node = batadv_orig_router_get(orig_node,
 220                                                     BATADV_IF_DEFAULT);
 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                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 233                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 234                 }
 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->version != BATADV_COMPAT_VERSION) {
 247                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 248                 icmp_header->version = BATADV_COMPAT_VERSION;
 249                 batadv_socket_add_packet(socket_client, icmp_header,
 250                                          packet_len);
 251                 goto free_skb;
 252         }
 253
 254         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 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 }