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
 162         if (len < sizeof(struct batadv_icmp_header)) {
 163                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 164                            "Error - can't send packet from char device: invalid packet size\n");
 165                 return -EINVAL;
 166         }
 167
 168         primary_if = batadv_primary_if_get_selected(bat_priv);
 169
 170         if (!primary_if) {
 171                 len = -EFAULT;
 172                 goto out;
 173         }
 174
 175         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 176                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 177         else
 178                 packet_len = len;
 179
 180         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 181         if (!skb) {
 182                 len = -ENOMEM;
 183                 goto out;
 184         }
 185
 186         skb->priority = TC_PRIO_CONTROL;
 187         skb_reserve(skb, ETH_HLEN);
 188         icmp_header = (struct batadv_icmp_header *)skb_put(skb, packet_len);
 189
 190         if (copy_from_user(icmp_header, buff, packet_len)) {
 191                 len = -EFAULT;
 192                 goto free_skb;
 193         }
 194
 195         if (icmp_header->packet_type != BATADV_ICMP) {
 196                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 197                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 198                 len = -EINVAL;
 199                 goto free_skb;
 200         }
 201
 202         switch (icmp_header->msg_type) {
 203         case BATADV_ECHO_REQUEST:
 204                 if (len < sizeof(struct batadv_icmp_packet)) {
 205                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 206                                    "Error - can't send packet from char device: invalid packet size\n");
 207                         len = -EINVAL;
 208                         goto free_skb;
 209                 }
 210
 211                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 212                         goto dst_unreach;
 213
 214                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 215                 if (!orig_node)
 216                         goto dst_unreach;
 217
 218                 neigh_node = batadv_orig_router_get(orig_node,
 219                                                     BATADV_IF_DEFAULT);
 220                 if (!neigh_node)
 221                         goto dst_unreach;
 222
 223                 if (!neigh_node->if_incoming)
 224                         goto dst_unreach;
 225
 226                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 227                         goto dst_unreach;
 228
 229                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 230                 if (packet_len == sizeof(*icmp_packet_rr))
 231                         memcpy(icmp_packet_rr->rr,
 232                                neigh_node->if_incoming->net_dev->dev_addr,
 233                                ETH_ALEN);
 234
 235                 break;
 236         default:
 237                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 238                            "Error - can't send packet from char device: got unknown message type\n");
 239                 len = -EINVAL;
 240                 goto free_skb;
 241         }
 242
 243         icmp_header->uid = socket_client->index;
 244
 245         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 246                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 247                 icmp_header->version = BATADV_COMPAT_VERSION;
 248                 batadv_socket_add_packet(socket_client, icmp_header,
 249                                          packet_len);
 250                 goto free_skb;
 251         }
 252
 253         memcpy(icmp_header->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 254
 255         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 256         goto out;
 257
 258 dst_unreach:
 259         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 260         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 261 free_skb:
 262         kfree_skb(skb);
 263 out:
 264         if (primary_if)
 265                 batadv_hardif_free_ref(primary_if);
 266         if (neigh_node)
 267                 batadv_neigh_node_free_ref(neigh_node);
 268         if (orig_node)
 269                 batadv_orig_node_free_ref(orig_node);
 270         return len;
 271 }
 272
 273 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 274 {
 275         struct batadv_socket_client *socket_client = file->private_data;
 276
 277         poll_wait(file, &socket_client->queue_wait, wait);
 278
 279         if (socket_client->queue_len > 0)
 280                 return POLLIN | POLLRDNORM;
 281
 282         return 0;
 283 }
 284
 285 static const struct file_operations batadv_fops = {
 286         .owner = THIS_MODULE,
 287         .open = batadv_socket_open,
 288         .release = batadv_socket_release,
 289         .read = batadv_socket_read,
 290         .write = batadv_socket_write,
 291         .poll = batadv_socket_poll,
 292         .llseek = no_llseek,
 293 };
 294
 295 int batadv_socket_setup(struct batadv_priv *bat_priv)
 296 {
 297         struct dentry *d;
 298
 299         if (!bat_priv->debug_dir)
 300                 goto err;
 301
 302         d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 303                                 bat_priv->debug_dir, bat_priv, &batadv_fops);
 304         if (!d)
 305                 goto err;
 306
 307         return 0;
 308
 309 err:
 310         return -ENOMEM;
 311 }
 312
 313 /**
 314  * batadv_socket_receive_packet - schedule an icmp packet to be sent to userspace
 315  *  on an icmp socket.
 316  * @socket_client: the socket this packet belongs to
 317  * @icmph: pointer to the header of the icmp packet
 318  * @icmp_len: total length of the icmp packet
 319  */
 320 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 321                                      struct batadv_icmp_header *icmph,
 322                                      size_t icmp_len)
 323 {
 324         struct batadv_socket_packet *socket_packet;
 325         size_t len;
 326
 327         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 328
 329         if (!socket_packet)
 330                 return;
 331
 332         len = icmp_len;
 333         /* check the maximum length before filling the buffer */
 334         if (len > sizeof(socket_packet->icmp_packet))
 335                 len = sizeof(socket_packet->icmp_packet);
 336
 337         INIT_LIST_HEAD(&socket_packet->list);
 338         memcpy(&socket_packet->icmp_packet, icmph, len);
 339         socket_packet->icmp_len = len;
 340
 341         spin_lock_bh(&socket_client->lock);
 342
 343         /* while waiting for the lock the socket_client could have been
 344          * deleted
 345          */
 346         if (!batadv_socket_client_hash[icmph->uid]) {
 347                 spin_unlock_bh(&socket_client->lock);
 348                 kfree(socket_packet);
 349                 return;
 350         }
 351
 352         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 353         socket_client->queue_len++;
 354
 355         if (socket_client->queue_len > 100) {
 356                 socket_packet = list_first_entry(&socket_client->queue_list,
 357                                                  struct batadv_socket_packet,
 358                                                  list);
 359
 360                 list_del(&socket_packet->list);
 361                 kfree(socket_packet);
 362                 socket_client->queue_len--;
 363         }
 364
 365         spin_unlock_bh(&socket_client->lock);
 366
 367         wake_up(&socket_client->queue_wait);
 368 }
 369
 370 /**
 371  * batadv_socket_receive_packet - schedule an icmp packet to be received
 372  *  locally and sent to userspace.
 373  * @icmph: pointer to the header of the icmp packet
 374  * @icmp_len: total length of the icmp packet
 375  */
 376 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 377                                   size_t icmp_len)
 378 {
 379         struct batadv_socket_client *hash;
 380
 381         hash = batadv_socket_client_hash[icmph->uid];
 382         if (hash)
 383                 batadv_socket_add_packet(hash, icmph, icmp_len);
 384 }