kernel/net/batman-adv/icmp_socket.c

   1 /* Copyright (C) 2007-2015 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 "originator.h"
  49 #include "packet.h"
  50 #include "send.h"
  51
  52 static struct batadv_socket_client *batadv_socket_client_hash[256];
  53
  54 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  55                                      struct batadv_icmp_header *icmph,
  56                                      size_t icmp_len);
  57
  58 void batadv_socket_init(void)
  59 {
  60         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  61 }
  62
  63 static int batadv_socket_open(struct inode *inode, struct file *file)
  64 {
  65         unsigned int i;
  66         struct batadv_socket_client *socket_client;
  67
  68         if (!try_module_get(THIS_MODULE))
  69                 return -EBUSY;
  70
  71         nonseekable_open(inode, file);
  72
  73         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  74         if (!socket_client) {
  75                 module_put(THIS_MODULE);
  76                 return -ENOMEM;
  77         }
  78
  79         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  80                 if (!batadv_socket_client_hash[i]) {
  81                         batadv_socket_client_hash[i] = socket_client;
  82                         break;
  83                 }
  84         }
  85
  86         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  87                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  88                 kfree(socket_client);
  89                 module_put(THIS_MODULE);
  90                 return -EXFULL;
  91         }
  92
  93         INIT_LIST_HEAD(&socket_client->queue_list);
  94         socket_client->queue_len = 0;
  95         socket_client->index = i;
  96         socket_client->bat_priv = inode->i_private;
  97         spin_lock_init(&socket_client->lock);
  98         init_waitqueue_head(&socket_client->queue_wait);
  99
 100         file->private_data = socket_client;
 101
 102         return 0;
 103 }
 104
 105 static int batadv_socket_release(struct inode *inode, struct file *file)
 106 {
 107         struct batadv_socket_client *socket_client = file->private_data;
 108         struct batadv_socket_packet *socket_packet;
 109         struct list_head *list_pos, *list_pos_tmp;
 110
 111         spin_lock_bh(&socket_client->lock);
 112
 113         /* for all packets in the queue ... */
 114         list_for_each_safe(list_pos, list_pos_tmp, &socket_client->queue_list) {
 115                 socket_packet = list_entry(list_pos,
 116                                            struct batadv_socket_packet, list);
 117
 118                 list_del(list_pos);
 119                 kfree(socket_packet);
 120         }
 121
 122         batadv_socket_client_hash[socket_client->index] = NULL;
 123         spin_unlock_bh(&socket_client->lock);
 124
 125         kfree(socket_client);
 126         module_put(THIS_MODULE);
 127
 128         return 0;
 129 }
 130
 131 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 132                                   size_t count, loff_t *ppos)
 133 {
 134         struct batadv_socket_client *socket_client = file->private_data;
 135         struct batadv_socket_packet *socket_packet;
 136         size_t packet_len;
 137         int error;
 138
 139         if ((file->f_flags & O_NONBLOCK) && (socket_client->queue_len == 0))
 140                 return -EAGAIN;
 141
 142         if ((!buf) || (count < sizeof(struct batadv_icmp_packet)))
 143                 return -EINVAL;
 144
 145         if (!access_ok(VERIFY_WRITE, buf, count))
 146                 return -EFAULT;
 147
 148         error = wait_event_interruptible(socket_client->queue_wait,
 149                                          socket_client->queue_len);
 150
 151         if (error)
 152                 return error;
 153
 154         spin_lock_bh(&socket_client->lock);
 155
 156         socket_packet = list_first_entry(&socket_client->queue_list,
 157                                          struct batadv_socket_packet, list);
 158         list_del(&socket_packet->list);
 159         socket_client->queue_len--;
 160
 161         spin_unlock_bh(&socket_client->lock);
 162
 163         packet_len = min(count, socket_packet->icmp_len);
 164         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 165
 166         kfree(socket_packet);
 167
 168         if (error)
 169                 return -EFAULT;
 170
 171         return packet_len;
 172 }
 173
 174 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 175                                    size_t len, loff_t *off)
 176 {
 177         struct batadv_socket_client *socket_client = file->private_data;
 178         struct batadv_priv *bat_priv = socket_client->bat_priv;
 179         struct batadv_hard_iface *primary_if = NULL;
 180         struct sk_buff *skb;
 181         struct batadv_icmp_packet_rr *icmp_packet_rr;
 182         struct batadv_icmp_header *icmp_header;
 183         struct batadv_orig_node *orig_node = NULL;
 184         struct batadv_neigh_node *neigh_node = NULL;
 185         size_t packet_len = sizeof(struct batadv_icmp_packet);
 186         u8 *addr;
 187
 188         if (len < sizeof(struct batadv_icmp_header)) {
 189                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 190                            "Error - can't send packet from char device: invalid packet size\n");
 191                 return -EINVAL;
 192         }
 193
 194         primary_if = batadv_primary_if_get_selected(bat_priv);
 195
 196         if (!primary_if) {
 197                 len = -EFAULT;
 198                 goto out;
 199         }
 200
 201         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 202                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 203         else
 204                 packet_len = len;
 205
 206         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 207         if (!skb) {
 208                 len = -ENOMEM;
 209                 goto out;
 210         }
 211
 212         skb->priority = TC_PRIO_CONTROL;
 213         skb_reserve(skb, ETH_HLEN);
 214         icmp_header = (struct batadv_icmp_header *)skb_put(skb, packet_len);
 215
 216         if (copy_from_user(icmp_header, buff, packet_len)) {
 217                 len = -EFAULT;
 218                 goto free_skb;
 219         }
 220
 221         if (icmp_header->packet_type != BATADV_ICMP) {
 222                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 223                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 224                 len = -EINVAL;
 225                 goto free_skb;
 226         }
 227
 228         switch (icmp_header->msg_type) {
 229         case BATADV_ECHO_REQUEST:
 230                 if (len < sizeof(struct batadv_icmp_packet)) {
 231                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 232                                    "Error - can't send packet from char device: invalid packet size\n");
 233                         len = -EINVAL;
 234                         goto free_skb;
 235                 }
 236
 237                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 238                         goto dst_unreach;
 239
 240                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 241                 if (!orig_node)
 242                         goto dst_unreach;
 243
 244                 neigh_node = batadv_orig_router_get(orig_node,
 245                                                     BATADV_IF_DEFAULT);
 246                 if (!neigh_node)
 247                         goto dst_unreach;
 248
 249                 if (!neigh_node->if_incoming)
 250                         goto dst_unreach;
 251
 252                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 253                         goto dst_unreach;
 254
 255                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 256                 if (packet_len == sizeof(*icmp_packet_rr)) {
 257                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 258                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 259                 }
 260
 261                 break;
 262         default:
 263                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 264                            "Error - can't send packet from char device: got unknown message type\n");
 265                 len = -EINVAL;
 266                 goto free_skb;
 267         }
 268
 269         icmp_header->uid = socket_client->index;
 270
 271         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 272                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 273                 icmp_header->version = BATADV_COMPAT_VERSION;
 274                 batadv_socket_add_packet(socket_client, icmp_header,
 275                                          packet_len);
 276                 goto free_skb;
 277         }
 278
 279         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 280
 281         batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 282         goto out;
 283
 284 dst_unreach:
 285         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 286         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 287 free_skb:
 288         kfree_skb(skb);
 289 out:
 290         if (primary_if)
 291                 batadv_hardif_free_ref(primary_if);
 292         if (neigh_node)
 293                 batadv_neigh_node_free_ref(neigh_node);
 294         if (orig_node)
 295                 batadv_orig_node_free_ref(orig_node);
 296         return len;
 297 }
 298
 299 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 300 {
 301         struct batadv_socket_client *socket_client = file->private_data;
 302
 303         poll_wait(file, &socket_client->queue_wait, wait);
 304
 305         if (socket_client->queue_len > 0)
 306                 return POLLIN | POLLRDNORM;
 307
 308         return 0;
 309 }
 310
 311 static const struct file_operations batadv_fops = {
 312         .owner = THIS_MODULE,
 313         .open = batadv_socket_open,
 314         .release = batadv_socket_release,
 315         .read = batadv_socket_read,
 316         .write = batadv_socket_write,
 317         .poll = batadv_socket_poll,
 318         .llseek = no_llseek,
 319 };
 320
 321 int batadv_socket_setup(struct batadv_priv *bat_priv)
 322 {
 323         struct dentry *d;
 324
 325         if (!bat_priv->debug_dir)
 326                 goto err;
 327
 328         d = debugfs_create_file(BATADV_ICMP_SOCKET, S_IFREG | S_IWUSR | S_IRUSR,
 329                                 bat_priv->debug_dir, bat_priv, &batadv_fops);
 330         if (!d)
 331                 goto err;
 332
 333         return 0;
 334
 335 err:
 336         return -ENOMEM;
 337 }
 338
 339 /**
 340  * batadv_socket_receive_packet - schedule an icmp packet to be sent to
 341  *  userspace on an icmp socket.
 342  * @socket_client: the socket this packet belongs to
 343  * @icmph: pointer to the header of the icmp packet
 344  * @icmp_len: total length of the icmp packet
 345  */
 346 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 347                                      struct batadv_icmp_header *icmph,
 348                                      size_t icmp_len)
 349 {
 350         struct batadv_socket_packet *socket_packet;
 351         size_t len;
 352
 353         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 354
 355         if (!socket_packet)
 356                 return;
 357
 358         len = icmp_len;
 359         /* check the maximum length before filling the buffer */
 360         if (len > sizeof(socket_packet->icmp_packet))
 361                 len = sizeof(socket_packet->icmp_packet);
 362
 363         INIT_LIST_HEAD(&socket_packet->list);
 364         memcpy(&socket_packet->icmp_packet, icmph, len);
 365         socket_packet->icmp_len = len;
 366
 367         spin_lock_bh(&socket_client->lock);
 368
 369         /* while waiting for the lock the socket_client could have been
 370          * deleted
 371          */
 372         if (!batadv_socket_client_hash[icmph->uid]) {
 373                 spin_unlock_bh(&socket_client->lock);
 374                 kfree(socket_packet);
 375                 return;
 376         }
 377
 378         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 379         socket_client->queue_len++;
 380
 381         if (socket_client->queue_len > 100) {
 382                 socket_packet = list_first_entry(&socket_client->queue_list,
 383                                                  struct batadv_socket_packet,
 384                                                  list);
 385
 386                 list_del(&socket_packet->list);
 387                 kfree(socket_packet);
 388                 socket_client->queue_len--;
 389         }
 390
 391         spin_unlock_bh(&socket_client->lock);
 392
 393         wake_up(&socket_client->queue_wait);
 394 }
 395
 396 /**
 397  * batadv_socket_receive_packet - schedule an icmp packet to be received
 398  *  locally and sent to userspace.
 399  * @icmph: pointer to the header of the icmp packet
 400  * @icmp_len: total length of the icmp packet
 401  */
 402 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 403                                   size_t icmp_len)
 404 {
 405         struct batadv_socket_client *hash;
 406
 407         hash = batadv_socket_client_hash[icmph->uid];
 408         if (hash)
 409                 batadv_socket_add_packet(hash, icmph, icmp_len);
 410 }