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 = dev_alloc_skb(packet_len + ETH_HLEN + NET_IP_ALIGN);
 181         if (!skb) {
 182                 len = -ENOMEM;
 183                 goto out;
 184         }
 185
 186         skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 187         icmp_packet = (struct batadv_icmp_packet_rr *)skb_put(skb, packet_len);
 188
 189         if (copy_from_user(icmp_packet, buff, packet_len)) {
 190                 len = -EFAULT;
 191                 goto free_skb;
 192         }
 193
 194         if (icmp_packet->header.packet_type != BATADV_ICMP) {
 195                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 196                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 197                 len = -EINVAL;
 198                 goto free_skb;
 199         }
 200
 201         if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
 202                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 203                            "Error - can't send packet from char device: got bogus message type (expected: ECHO_REQUEST)\n");
 204                 len = -EINVAL;
 205                 goto free_skb;
 206         }
 207
 208         icmp_packet->uid = socket_client->index;
 209
 210         if (icmp_packet->header.version != BATADV_COMPAT_VERSION) {
 211                 icmp_packet->msg_type = BATADV_PARAMETER_PROBLEM;
 212                 icmp_packet->header.version = BATADV_COMPAT_VERSION;
 213                 batadv_socket_add_packet(socket_client, icmp_packet,
 214                                          packet_len);
 215                 goto free_skb;
 216         }
 217
 218         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 219                 goto dst_unreach;
 220
 221         orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->dst);
 222         if (!orig_node)
 223                 goto dst_unreach;
 224
 225         neigh_node = batadv_orig_node_get_router(orig_node);
 226         if (!neigh_node)
 227                 goto dst_unreach;
 228
 229         if (!neigh_node->if_incoming)
 230                 goto dst_unreach;
 231
 232         if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 233                 goto dst_unreach;
 234
 235         memcpy(icmp_packet->orig,
 236                primary_if->net_dev->dev_addr, ETH_ALEN);
 237
 238         if (packet_len == sizeof(struct batadv_icmp_packet_rr))
 239                 memcpy(icmp_packet->rr,
 240                        neigh_node->if_incoming->net_dev->dev_addr, ETH_ALEN);
 241
 242         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 243         goto out;
 244
 245 dst_unreach:
 246         icmp_packet->msg_type = BATADV_DESTINATION_UNREACHABLE;
 247         batadv_socket_add_packet(socket_client, icmp_packet, packet_len);
 248 free_skb:
 249         kfree_skb(skb);
 250 out:
 251         if (primary_if)
 252                 batadv_hardif_free_ref(primary_if);
 253         if (neigh_node)
 254                 batadv_neigh_node_free_ref(neigh_node);
 255         if (orig_node)
 256                 batadv_orig_node_free_ref(orig_node);
 257         return len;
 258 }
 259
 260 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 261 {
 262         struct batadv_socket_client *socket_client = file->private_data;
 263
 264         poll_wait(file, &socket_client->queue_wait, wait);
 265
 266         if (socket_client->queue_len > 0)
 267                 return POLLIN | POLLRDNORM;
 268
 269         return 0;
 270 }
 271
 272 static const struct file_operations batadv_fops = {
 273         .owner = THIS_MODULE,
 274         .open = batadv_socket_open,
 275         .release = batadv_socket_release,
 276         .read = batadv_socket_read,
 277         .write = batadv_socket_write,
 278         .poll = batadv_socket_poll,
 279         .llseek = no_llseek,
 280 };
 281
 282 int batadv_socket_setup(struct batadv_priv *bat_priv)
 283 {
 284         struct dentry *d;
 285
 286         if (!bat_priv->debug_dir)
 287                 goto err;
 288
 289         d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 290                                 bat_priv->debug_dir, bat_priv, &batadv_fops);
 291         if (!d)
 292                 goto err;
 293
 294         return 0;
 295
 296 err:
 297         return -ENOMEM;
 298 }
 299
 300 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 301                                      struct batadv_icmp_packet_rr *icmp_packet,
 302                                      size_t icmp_len)
 303 {
 304         struct batadv_socket_packet *socket_packet;
 305
 306         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 307
 308         if (!socket_packet)
 309                 return;
 310
 311         INIT_LIST_HEAD(&socket_packet->list);
 312         memcpy(&socket_packet->icmp_packet, icmp_packet, icmp_len);
 313         socket_packet->icmp_len = icmp_len;
 314
 315         spin_lock_bh(&socket_client->lock);
 316
 317         /* while waiting for the lock the socket_client could have been
 318          * deleted
 319          */
 320         if (!batadv_socket_client_hash[icmp_packet->uid]) {
 321                 spin_unlock_bh(&socket_client->lock);
 322                 kfree(socket_packet);
 323                 return;
 324         }
 325
 326         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 327         socket_client->queue_len++;
 328
 329         if (socket_client->queue_len > 100) {
 330                 socket_packet = list_first_entry(&socket_client->queue_list,
 331                                                  struct batadv_socket_packet,
 332                                                  list);
 333
 334                 list_del(&socket_packet->list);
 335                 kfree(socket_packet);
 336                 socket_client->queue_len--;
 337         }
 338
 339         spin_unlock_bh(&socket_client->lock);
 340
 341         wake_up(&socket_client->queue_wait);
 342 }
 343
 344 void batadv_socket_receive_packet(struct batadv_icmp_packet_rr *icmp_packet,
 345                                   size_t icmp_len)
 346 {
 347         struct batadv_socket_client *hash;
 348
 349         hash = batadv_socket_client_hash[icmp_packet->uid];
 350         if (hash)
 351                 batadv_socket_add_packet(hash, icmp_packet, icmp_len);
 352 }