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_packet_rr *icmp_packet,
  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;
 159
 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_packet)) {
 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 >= sizeof(struct batadv_icmp_packet_rr))
 178                 packet_len = sizeof(struct batadv_icmp_packet_rr);
 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_packet = (struct batadv_icmp_packet_rr *)skb_put(skb, packet_len);
 189
 190         if (copy_from_user(icmp_packet, buff, packet_len)) {
 191                 len = -EFAULT;
 192                 goto free_skb;
 193         }
 194
 195         if (icmp_packet->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         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 203                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 204                            "Error - can't send packet from char device: 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->header.version != BATADV_COMPAT_VERSION) {
 212                 icmp_packet->msg_type = BATADV_PARAMETER_PROBLEM;
 213                 icmp_packet->header.version = BATADV_COMPAT_VERSION;
 214                 batadv_socket_add_packet(socket_client, icmp_packet,
 215                                          packet_len);
 216                 goto free_skb;
 217         }
 218
 219         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 220                 goto dst_unreach;
 221
 222         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
 223         if (!orig_node)
 224                 goto dst_unreach;
 225
 226         neigh_node = batadv_orig_node_get_router(orig_node);
 227         if (!neigh_node)
 228                 goto dst_unreach;
 229
 230         if (!neigh_node->if_incoming)
 231                 goto dst_unreach;
 232
 233         if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 234                 goto dst_unreach;
 235
 236         memcpy(icmp_packet->orig,
 237                primary_if->net_dev->dev_addr, ETH_ALEN);
 238
 239         if (packet_len == sizeof(struct batadv_icmp_packet_rr))
 240                 memcpy(icmp_packet->rr,
 241                        neigh_node->if_incoming->net_dev->dev_addr, ETH_ALEN);
 242
 243         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 244         goto out;
 245
 246 dst_unreach:
 247         icmp_packet->msg_type = BATADV_DESTINATION_UNREACHABLE;
 248         batadv_socket_add_packet(socket_client, icmp_packet, packet_len);
 249 free_skb:
 250         kfree_skb(skb);
 251 out:
 252         if (primary_if)
 253                 batadv_hardif_free_ref(primary_if);
 254         if (neigh_node)
 255                 batadv_neigh_node_free_ref(neigh_node);
 256         if (orig_node)
 257                 batadv_orig_node_free_ref(orig_node);
 258         return len;
 259 }
 260
 261 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 262 {
 263         struct batadv_socket_client *socket_client = file->private_data;
 264
 265         poll_wait(file, &socket_client->queue_wait, wait);
 266
 267         if (socket_client->queue_len > 0)
 268                 return POLLIN | POLLRDNORM;
 269
 270         return 0;
 271 }
 272
 273 static const struct file_operations batadv_fops = {
 274         .owner = THIS_MODULE,
 275         .open = batadv_socket_open,
 276         .release = batadv_socket_release,
 277         .read = batadv_socket_read,
 278         .write = batadv_socket_write,
 279         .poll = batadv_socket_poll,
 280         .llseek = no_llseek,
 281 };
 282
 283 int batadv_socket_setup(struct batadv_priv *bat_priv)
 284 {
 285         struct dentry *d;
 286
 287         if (!bat_priv->debug_dir)
 288                 goto err;
 289
 290         d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 291                                 bat_priv->debug_dir, bat_priv, &batadv_fops);
 292         if (!d)
 293                 goto err;
 294
 295         return 0;
 296
 297 err:
 298         return -ENOMEM;
 299 }
 300
 301 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 302                                      struct batadv_icmp_packet_rr *icmp_packet,
 303                                      size_t icmp_len)
 304 {
 305         struct batadv_socket_packet *socket_packet;
 306
 307         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 308
 309         if (!socket_packet)
 310                 return;
 311
 312         INIT_LIST_HEAD(&socket_packet->list);
 313         memcpy(&socket_packet->icmp_packet, icmp_packet, icmp_len);
 314         socket_packet->icmp_len = icmp_len;
 315
 316         spin_lock_bh(&socket_client->lock);
 317
 318         /* while waiting for the lock the socket_client could have been
 319          * deleted
 320          */
 321         if (!batadv_socket_client_hash[icmp_packet->uid]) {
 322                 spin_unlock_bh(&socket_client->lock);
 323                 kfree(socket_packet);
 324                 return;
 325         }
 326
 327         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 328         socket_client->queue_len++;
 329
 330         if (socket_client->queue_len > 100) {
 331                 socket_packet = list_first_entry(&socket_client->queue_list,
 332                                                  struct batadv_socket_packet,
 333                                                  list);
 334
 335                 list_del(&socket_packet->list);
 336                 kfree(socket_packet);
 337                 socket_client->queue_len--;
 338         }
 339
 340         spin_unlock_bh(&socket_client->lock);
 341
 342         wake_up(&socket_client->queue_wait);
 343 }
 344
 345 void batadv_socket_receive_packet(struct batadv_icmp_packet_rr *icmp_packet,
 346                                   size_t icmp_len)
 347 {
 348         struct batadv_socket_client *hash;
 349
 350         hash = batadv_socket_client_hash[icmp_packet->uid];
 351         if (hash)
 352                 batadv_socket_add_packet(hash, icmp_packet, icmp_len);
 353 }