net/batman-adv/icmp_socket.c

   1 /* Copyright (C) 2007-2016  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 "icmp_socket.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/compiler.h>
  23 #include <linux/debugfs.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/export.h>
  27 #include <linux/fcntl.h>
  28 #include <linux/fs.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/kernel.h>
  31 #include <linux/list.h>
  32 #include <linux/module.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/pkt_sched.h>
  35 #include <linux/poll.h>
  36 #include <linux/printk.h>
  37 #include <linux/sched.h> /* for linux/wait.h */
  38 #include <linux/skbuff.h>
  39 #include <linux/slab.h>
  40 #include <linux/spinlock.h>
  41 #include <linux/stat.h>
  42 #include <linux/stddef.h>
  43 #include <linux/string.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/wait.h>
  46
  47 #include "hard-interface.h"
  48 #include "log.h"
  49 #include "originator.h"
  50 #include "packet.h"
  51 #include "send.h"
  52
  53 static struct batadv_socket_client *batadv_socket_client_hash[256];
  54
  55 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  56                                      struct batadv_icmp_header *icmph,
  57                                      size_t icmp_len);
  58
  59 void batadv_socket_init(void)
  60 {
  61         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  62 }
  63
  64 static int batadv_socket_open(struct inode *inode, struct file *file)
  65 {
  66         unsigned int i;
  67         struct batadv_socket_client *socket_client;
  68
  69         if (!try_module_get(THIS_MODULE))
  70                 return -EBUSY;
  71
  72         nonseekable_open(inode, file);
  73
  74         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  75         if (!socket_client) {
  76                 module_put(THIS_MODULE);
  77                 return -ENOMEM;
  78         }
  79
  80         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  81                 if (!batadv_socket_client_hash[i]) {
  82                         batadv_socket_client_hash[i] = socket_client;
  83                         break;
  84                 }
  85         }
  86
  87         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  88                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  89                 kfree(socket_client);
  90                 module_put(THIS_MODULE);
  91                 return -EXFULL;
  92         }
  93
  94         INIT_LIST_HEAD(&socket_client->queue_list);
  95         socket_client->queue_len = 0;
  96         socket_client->index = i;
  97         socket_client->bat_priv = inode->i_private;
  98         spin_lock_init(&socket_client->lock);
  99         init_waitqueue_head(&socket_client->queue_wait);
 100
 101         file->private_data = socket_client;
 102
 103         return 0;
 104 }
 105
 106 static int batadv_socket_release(struct inode *inode, struct file *file)
 107 {
 108         struct batadv_socket_client *client = file->private_data;
 109         struct batadv_socket_packet *packet, *tmp;
 110
 111         spin_lock_bh(&client->lock);
 112
 113         /* for all packets in the queue ... */
 114         list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
 115                 list_del(&packet->list);
 116                 kfree(packet);
 117         }
 118
 119         batadv_socket_client_hash[client->index] = NULL;
 120         spin_unlock_bh(&client->lock);
 121
 122         kfree(client);
 123         module_put(THIS_MODULE);
 124
 125         return 0;
 126 }
 127
 128 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 129                                   size_t count, loff_t *ppos)
 130 {
 131         struct batadv_socket_client *socket_client = file->private_data;
 132         struct batadv_socket_packet *socket_packet;
 133         size_t packet_len;
 134         int error;
 135
 136         if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
 137                 return -EAGAIN;
 138
 139         if ((!buf) || (count < sizeof(struct batadv_icmp_packet)))
 140                 return -EINVAL;
 141
 142         if (!access_ok(VERIFY_WRITE, buf, count))
 143                 return -EFAULT;
 144
 145         error = wait_event_interruptible(socket_client->queue_wait,
 146                                          socket_client->queue_len);
 147
 148         if (error)
 149                 return error;
 150
 151         spin_lock_bh(&socket_client->lock);
 152
 153         socket_packet = list_first_entry(&socket_client->queue_list,
 154                                          struct batadv_socket_packet, list);
 155         list_del(&socket_packet->list);
 156         socket_client->queue_len--;
 157
 158         spin_unlock_bh(&socket_client->lock);
 159
 160         packet_len = min(count, socket_packet->icmp_len);
 161         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 162
 163         kfree(socket_packet);
 164
 165         if (error)
 166                 return -EFAULT;
 167
 168         return packet_len;
 169 }
 170
 171 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 172                                    size_t len, loff_t *off)
 173 {
 174         struct batadv_socket_client *socket_client = file->private_data;
 175         struct batadv_priv *bat_priv = socket_client->bat_priv;
 176         struct batadv_hard_iface *primary_if = NULL;
 177         struct sk_buff *skb;
 178         struct batadv_icmp_packet_rr *icmp_packet_rr;
 179         struct batadv_icmp_header *icmp_header;
 180         struct batadv_orig_node *orig_node = NULL;
 181         struct batadv_neigh_node *neigh_node = NULL;
 182         size_t packet_len = sizeof(struct batadv_icmp_packet);
 183         u8 *addr;
 184
 185         if (len < sizeof(struct batadv_icmp_header)) {
 186                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 187                            "Error - can't send packet from char device: invalid packet size\n");
 188                 return -EINVAL;
 189         }
 190
 191         primary_if = batadv_primary_if_get_selected(bat_priv);
 192
 193         if (!primary_if) {
 194                 len = -EFAULT;
 195                 goto out;
 196         }
 197
 198         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 199                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 200         else
 201                 packet_len = len;
 202
 203         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 204         if (!skb) {
 205                 len = -ENOMEM;
 206                 goto out;
 207         }
 208
 209         skb->priority = TC_PRIO_CONTROL;
 210         skb_reserve(skb, ETH_HLEN);
 211         icmp_header = (struct batadv_icmp_header *)skb_put(skb, packet_len);
 212
 213         if (copy_from_user(icmp_header, buff, packet_len)) {
 214                 len = -EFAULT;
 215                 goto free_skb;
 216         }
 217
 218         if (icmp_header->packet_type != BATADV_ICMP) {
 219                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 220                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 221                 len = -EINVAL;
 222                 goto free_skb;
 223         }
 224
 225         switch (icmp_header->msg_type) {
 226         case BATADV_ECHO_REQUEST:
 227                 if (len < sizeof(struct batadv_icmp_packet)) {
 228                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 229                                    "Error - can't send packet from char device: invalid packet size\n");
 230                         len = -EINVAL;
 231                         goto free_skb;
 232                 }
 233
 234                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 235                         goto dst_unreach;
 236
 237                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 238                 if (!orig_node)
 239                         goto dst_unreach;
 240
 241                 neigh_node = batadv_orig_router_get(orig_node,
 242                                                     BATADV_IF_DEFAULT);
 243                 if (!neigh_node)
 244                         goto dst_unreach;
 245
 246                 if (!neigh_node->if_incoming)
 247                         goto dst_unreach;
 248
 249                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 250                         goto dst_unreach;
 251
 252                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 253                 if (packet_len == sizeof(*icmp_packet_rr)) {
 254                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 255                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 256                 }
 257
 258                 break;
 259         default:
 260                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 261                            "Error - can't send packet from char device: got unknown message type\n");
 262                 len = -EINVAL;
 263                 goto free_skb;
 264         }
 265
 266         icmp_header->uid = socket_client->index;
 267
 268         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 269                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 270                 icmp_header->version = BATADV_COMPAT_VERSION;
 271                 batadv_socket_add_packet(socket_client, icmp_header,
 272                                          packet_len);
 273                 goto free_skb;
 274         }
 275
 276         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 277
 278         batadv_send_unicast_skb(skb, neigh_node);
 279         goto out;
 280
 281 dst_unreach:
 282         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 283         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 284 free_skb:
 285         kfree_skb(skb);
 286 out:
 287         if (primary_if)
 288                 batadv_hardif_put(primary_if);
 289         if (neigh_node)
 290                 batadv_neigh_node_put(neigh_node);
 291         if (orig_node)
 292                 batadv_orig_node_put(orig_node);
 293         return len;
 294 }
 295
 296 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 297 {
 298         struct batadv_socket_client *socket_client = file->private_data;
 299
 300         poll_wait(file, &socket_client->queue_wait, wait);
 301
 302         if (socket_client->queue_len > 0)
 303                 return POLLIN | POLLRDNORM;
 304
 305         return 0;
 306 }
 307
 308 static const struct file_operations batadv_fops = {
 309         .owner = THIS_MODULE,
 310         .open = batadv_socket_open,
 311         .release = batadv_socket_release,
 312         .read = batadv_socket_read,
 313         .write = batadv_socket_write,
 314         .poll = batadv_socket_poll,
 315         .llseek = no_llseek,
 316 };
 317
 318 int batadv_socket_setup(struct batadv_priv *bat_priv)
 319 {
 320         struct dentry *d;
 321
 322         if (!bat_priv->debug_dir)
 323                 goto err;
 324
 325         d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 326                                 bat_priv->debug_dir, bat_priv, &batadv_fops);
 327         if (!d)
 328                 goto err;
 329
 330         return 0;
 331
 332 err:
 333         return -ENOMEM;
 334 }
 335
 336 /**
 337  * batadv_socket_add_packet - schedule an icmp packet to be sent to
 338  *  userspace on an icmp socket.
 339  * @socket_client: the socket this packet belongs to
 340  * @icmph: pointer to the header of the icmp packet
 341  * @icmp_len: total length of the icmp packet
 342  */
 343 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 344                                      struct batadv_icmp_header *icmph,
 345                                      size_t icmp_len)
 346 {
 347         struct batadv_socket_packet *socket_packet;
 348         size_t len;
 349
 350         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 351
 352         if (!socket_packet)
 353                 return;
 354
 355         len = icmp_len;
 356         /* check the maximum length before filling the buffer */
 357         if (len > sizeof(socket_packet->icmp_packet))
 358                 len = sizeof(socket_packet->icmp_packet);
 359
 360         INIT_LIST_HEAD(&socket_packet->list);
 361         memcpy(&socket_packet->icmp_packet, icmph, len);
 362         socket_packet->icmp_len = len;
 363
 364         spin_lock_bh(&socket_client->lock);
 365
 366         /* while waiting for the lock the socket_client could have been
 367          * deleted
 368          */
 369         if (!batadv_socket_client_hash[icmph->uid]) {
 370                 spin_unlock_bh(&socket_client->lock);
 371                 kfree(socket_packet);
 372                 return;
 373         }
 374
 375         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 376         socket_client->queue_len++;
 377
 378         if (socket_client->queue_len > 100) {
 379                 socket_packet = list_first_entry(&socket_client->queue_list,
 380                                                  struct batadv_socket_packet,
 381                                                  list);
 382
 383                 list_del(&socket_packet->list);
 384                 kfree(socket_packet);
 385                 socket_client->queue_len--;
 386         }
 387
 388         spin_unlock_bh(&socket_client->lock);
 389
 390         wake_up(&socket_client->queue_wait);
 391 }
 392
 393 /**
 394  * batadv_socket_receive_packet - schedule an icmp packet to be received
 395  *  locally and sent to userspace.
 396  * @icmph: pointer to the header of the icmp packet
 397  * @icmp_len: total length of the icmp packet
 398  */
 399 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 400                                   size_t icmp_len)
 401 {
 402         struct batadv_socket_client *hash;
 403
 404         hash = batadv_socket_client_hash[icmph->uid];
 405         if (hash)
 406                 batadv_socket_add_packet(hash, icmph, icmp_len);
 407 }