net/batman-adv/icmp_socket.c

   1 /* Copyright (C) 2007-2017  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/stddef.h>
  42 #include <linux/string.h>
  43 #include <linux/uaccess.h>
  44 #include <linux/wait.h>
  45
  46 #include "hard-interface.h"
  47 #include "log.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 *client = file->private_data;
 108         struct batadv_socket_packet *packet, *tmp;
 109
 110         spin_lock_bh(&client->lock);
 111
 112         /* for all packets in the queue ... */
 113         list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
 114                 list_del(&packet->list);
 115                 kfree(packet);
 116         }
 117
 118         batadv_socket_client_hash[client->index] = NULL;
 119         spin_unlock_bh(&client->lock);
 120
 121         kfree(client);
 122         module_put(THIS_MODULE);
 123
 124         return 0;
 125 }
 126
 127 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 128                                   size_t count, loff_t *ppos)
 129 {
 130         struct batadv_socket_client *socket_client = file->private_data;
 131         struct batadv_socket_packet *socket_packet;
 132         size_t packet_len;
 133         int error;
 134
 135         if ((file->f_flags & O_NONBLOCK) && socket_client->queue_len == 0)
 136                 return -EAGAIN;
 137
 138         if (!buf || count < sizeof(struct batadv_icmp_packet))
 139                 return -EINVAL;
 140
 141         if (!access_ok(VERIFY_WRITE, buf, count))
 142                 return -EFAULT;
 143
 144         error = wait_event_interruptible(socket_client->queue_wait,
 145                                          socket_client->queue_len);
 146
 147         if (error)
 148                 return error;
 149
 150         spin_lock_bh(&socket_client->lock);
 151
 152         socket_packet = list_first_entry(&socket_client->queue_list,
 153                                          struct batadv_socket_packet, list);
 154         list_del(&socket_packet->list);
 155         socket_client->queue_len--;
 156
 157         spin_unlock_bh(&socket_client->lock);
 158
 159         packet_len = min(count, socket_packet->icmp_len);
 160         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 161
 162         kfree(socket_packet);
 163
 164         if (error)
 165                 return -EFAULT;
 166
 167         return packet_len;
 168 }
 169
 170 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 171                                    size_t len, loff_t *off)
 172 {
 173         struct batadv_socket_client *socket_client = file->private_data;
 174         struct batadv_priv *bat_priv = socket_client->bat_priv;
 175         struct batadv_hard_iface *primary_if = NULL;
 176         struct sk_buff *skb;
 177         struct batadv_icmp_packet_rr *icmp_packet_rr;
 178         struct batadv_icmp_header *icmp_header;
 179         struct batadv_orig_node *orig_node = NULL;
 180         struct batadv_neigh_node *neigh_node = NULL;
 181         size_t packet_len = sizeof(struct batadv_icmp_packet);
 182         u8 *addr;
 183
 184         if (len < sizeof(struct batadv_icmp_header)) {
 185                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 186                            "Error - can't send packet from char device: invalid packet size\n");
 187                 return -EINVAL;
 188         }
 189
 190         primary_if = batadv_primary_if_get_selected(bat_priv);
 191
 192         if (!primary_if) {
 193                 len = -EFAULT;
 194                 goto out;
 195         }
 196
 197         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 198                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 199         else
 200                 packet_len = len;
 201
 202         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 203         if (!skb) {
 204                 len = -ENOMEM;
 205                 goto out;
 206         }
 207
 208         skb->priority = TC_PRIO_CONTROL;
 209         skb_reserve(skb, ETH_HLEN);
 210         icmp_header = skb_put(skb, packet_len);
 211
 212         if (copy_from_user(icmp_header, buff, packet_len)) {
 213                 len = -EFAULT;
 214                 goto free_skb;
 215         }
 216
 217         if (icmp_header->packet_type != BATADV_ICMP) {
 218                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 219                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 220                 len = -EINVAL;
 221                 goto free_skb;
 222         }
 223
 224         switch (icmp_header->msg_type) {
 225         case BATADV_ECHO_REQUEST:
 226                 if (len < sizeof(struct batadv_icmp_packet)) {
 227                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 228                                    "Error - can't send packet from char device: invalid packet size\n");
 229                         len = -EINVAL;
 230                         goto free_skb;
 231                 }
 232
 233                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 234                         goto dst_unreach;
 235
 236                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 237                 if (!orig_node)
 238                         goto dst_unreach;
 239
 240                 neigh_node = batadv_orig_router_get(orig_node,
 241                                                     BATADV_IF_DEFAULT);
 242                 if (!neigh_node)
 243                         goto dst_unreach;
 244
 245                 if (!neigh_node->if_incoming)
 246                         goto dst_unreach;
 247
 248                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 249                         goto dst_unreach;
 250
 251                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 252                 if (packet_len == sizeof(*icmp_packet_rr)) {
 253                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 254                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 255                 }
 256
 257                 break;
 258         default:
 259                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 260                            "Error - can't send packet from char device: got unknown message type\n");
 261                 len = -EINVAL;
 262                 goto free_skb;
 263         }
 264
 265         icmp_header->uid = socket_client->index;
 266
 267         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 268                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 269                 icmp_header->version = BATADV_COMPAT_VERSION;
 270                 batadv_socket_add_packet(socket_client, icmp_header,
 271                                          packet_len);
 272                 goto free_skb;
 273         }
 274
 275         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 276
 277         batadv_send_unicast_skb(skb, neigh_node);
 278         goto out;
 279
 280 dst_unreach:
 281         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 282         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 283 free_skb:
 284         kfree_skb(skb);
 285 out:
 286         if (primary_if)
 287                 batadv_hardif_put(primary_if);
 288         if (neigh_node)
 289                 batadv_neigh_node_put(neigh_node);
 290         if (orig_node)
 291                 batadv_orig_node_put(orig_node);
 292         return len;
 293 }
 294
 295 static unsigned int batadv_socket_poll(struct file *file, poll_table *wait)
 296 {
 297         struct batadv_socket_client *socket_client = file->private_data;
 298
 299         poll_wait(file, &socket_client->queue_wait, wait);
 300
 301         if (socket_client->queue_len > 0)
 302                 return POLLIN | POLLRDNORM;
 303
 304         return 0;
 305 }
 306
 307 static const struct file_operations batadv_fops = {
 308         .owner = THIS_MODULE,
 309         .open = batadv_socket_open,
 310         .release = batadv_socket_release,
 311         .read = batadv_socket_read,
 312         .write = batadv_socket_write,
 313         .poll = batadv_socket_poll,
 314         .llseek = no_llseek,
 315 };
 316
 317 int batadv_socket_setup(struct batadv_priv *bat_priv)
 318 {
 319         struct dentry *d;
 320
 321         if (!bat_priv->debug_dir)
 322                 goto err;
 323
 324         d = debugfs_create_file(BATADV_ICMP_SOCKET, 0600, bat_priv->debug_dir,
 325                                 bat_priv, &batadv_fops);
 326         if (!d)
 327                 goto err;
 328
 329         return 0;
 330
 331 err:
 332         return -ENOMEM;
 333 }
 334
 335 /**
 336  * batadv_socket_add_packet - schedule an icmp packet to be sent to
 337  *  userspace on an icmp socket.
 338  * @socket_client: the socket this packet belongs to
 339  * @icmph: pointer to the header of the icmp packet
 340  * @icmp_len: total length of the icmp packet
 341  */
 342 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 343                                      struct batadv_icmp_header *icmph,
 344                                      size_t icmp_len)
 345 {
 346         struct batadv_socket_packet *socket_packet;
 347         size_t len;
 348
 349         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 350
 351         if (!socket_packet)
 352                 return;
 353
 354         len = icmp_len;
 355         /* check the maximum length before filling the buffer */
 356         if (len > sizeof(socket_packet->icmp_packet))
 357                 len = sizeof(socket_packet->icmp_packet);
 358
 359         INIT_LIST_HEAD(&socket_packet->list);
 360         memcpy(&socket_packet->icmp_packet, icmph, len);
 361         socket_packet->icmp_len = len;
 362
 363         spin_lock_bh(&socket_client->lock);
 364
 365         /* while waiting for the lock the socket_client could have been
 366          * deleted
 367          */
 368         if (!batadv_socket_client_hash[icmph->uid]) {
 369                 spin_unlock_bh(&socket_client->lock);
 370                 kfree(socket_packet);
 371                 return;
 372         }
 373
 374         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 375         socket_client->queue_len++;
 376
 377         if (socket_client->queue_len > 100) {
 378                 socket_packet = list_first_entry(&socket_client->queue_list,
 379                                                  struct batadv_socket_packet,
 380                                                  list);
 381
 382                 list_del(&socket_packet->list);
 383                 kfree(socket_packet);
 384                 socket_client->queue_len--;
 385         }
 386
 387         spin_unlock_bh(&socket_client->lock);
 388
 389         wake_up(&socket_client->queue_wait);
 390 }
 391
 392 /**
 393  * batadv_socket_receive_packet - schedule an icmp packet to be received
 394  *  locally and sent to userspace.
 395  * @icmph: pointer to the header of the icmp packet
 396  * @icmp_len: total length of the icmp packet
 397  */
 398 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 399                                   size_t icmp_len)
 400 {
 401         struct batadv_socket_client *hash;
 402
 403         hash = batadv_socket_client_hash[icmph->uid];
 404         if (hash)
 405                 batadv_socket_add_packet(hash, icmph, icmp_len);
 406 }