net/batman-adv/icmp_socket.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2007-2017  B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "icmp_socket.h"
  20 #include "main.h"
  21
  22 #include <linux/atomic.h>
  23 #include <linux/compiler.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/errno.h>
  26 #include <linux/etherdevice.h>
  27 #include <linux/eventpoll.h>
  28 #include <linux/export.h>
  29 #include <linux/fcntl.h>
  30 #include <linux/fs.h>
  31 #include <linux/gfp.h>
  32 #include <linux/if_ether.h>
  33 #include <linux/kernel.h>
  34 #include <linux/list.h>
  35 #include <linux/module.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/pkt_sched.h>
  38 #include <linux/poll.h>
  39 #include <linux/printk.h>
  40 #include <linux/sched.h> /* for linux/wait.h */
  41 #include <linux/skbuff.h>
  42 #include <linux/slab.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/stddef.h>
  45 #include <linux/string.h>
  46 #include <linux/uaccess.h>
  47 #include <linux/wait.h>
  48 #include <uapi/linux/batadv_packet.h>
  49
  50 #include "hard-interface.h"
  51 #include "log.h"
  52 #include "originator.h"
  53 #include "send.h"
  54
  55 static struct batadv_socket_client *batadv_socket_client_hash[256];
  56
  57 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  58                                      struct batadv_icmp_header *icmph,
  59                                      size_t icmp_len);
  60
  61 /**
  62  * batadv_socket_init() - Initialize soft interface independent socket data
  63  */
  64 void batadv_socket_init(void)
  65 {
  66         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  67 }
  68
  69 static int batadv_socket_open(struct inode *inode, struct file *file)
  70 {
  71         unsigned int i;
  72         struct batadv_socket_client *socket_client;
  73
  74         if (!try_module_get(THIS_MODULE))
  75                 return -EBUSY;
  76
  77         nonseekable_open(inode, file);
  78
  79         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  80         if (!socket_client) {
  81                 module_put(THIS_MODULE);
  82                 return -ENOMEM;
  83         }
  84
  85         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  86                 if (!batadv_socket_client_hash[i]) {
  87                         batadv_socket_client_hash[i] = socket_client;
  88                         break;
  89                 }
  90         }
  91
  92         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  93                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  94                 kfree(socket_client);
  95                 module_put(THIS_MODULE);
  96                 return -EXFULL;
  97         }
  98
  99         INIT_LIST_HEAD(&socket_client->queue_list);
 100         socket_client->queue_len = 0;
 101         socket_client->index = i;
 102         socket_client->bat_priv = inode->i_private;
 103         spin_lock_init(&socket_client->lock);
 104         init_waitqueue_head(&socket_client->queue_wait);
 105
 106         file->private_data = socket_client;
 107
 108         return 0;
 109 }
 110
 111 static int batadv_socket_release(struct inode *inode, struct file *file)
 112 {
 113         struct batadv_socket_client *client = file->private_data;
 114         struct batadv_socket_packet *packet, *tmp;
 115
 116         spin_lock_bh(&client->lock);
 117
 118         /* for all packets in the queue ... */
 119         list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
 120                 list_del(&packet->list);
 121                 kfree(packet);
 122         }
 123
 124         batadv_socket_client_hash[client->index] = NULL;
 125         spin_unlock_bh(&client->lock);
 126
 127         kfree(client);
 128         module_put(THIS_MODULE);
 129
 130         return 0;
 131 }
 132
 133 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 134                                   size_t count, loff_t *ppos)
 135 {
 136         struct batadv_socket_client *socket_client = file->private_data;
 137         struct batadv_socket_packet *socket_packet;
 138         size_t packet_len;
 139         int error;
 140
 141         if ((file->f_flags & O_NONBLOCK) && socket_client->queue_len == 0)
 142                 return -EAGAIN;
 143
 144         if (!buf || count < sizeof(struct batadv_icmp_packet))
 145                 return -EINVAL;
 146
 147         if (!access_ok(VERIFY_WRITE, buf, count))
 148                 return -EFAULT;
 149
 150         error = wait_event_interruptible(socket_client->queue_wait,
 151                                          socket_client->queue_len);
 152
 153         if (error)
 154                 return error;
 155
 156         spin_lock_bh(&socket_client->lock);
 157
 158         socket_packet = list_first_entry(&socket_client->queue_list,
 159                                          struct batadv_socket_packet, list);
 160         list_del(&socket_packet->list);
 161         socket_client->queue_len--;
 162
 163         spin_unlock_bh(&socket_client->lock);
 164
 165         packet_len = min(count, socket_packet->icmp_len);
 166         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 167
 168         kfree(socket_packet);
 169
 170         if (error)
 171                 return -EFAULT;
 172
 173         return packet_len;
 174 }
 175
 176 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 177                                    size_t len, loff_t *off)
 178 {
 179         struct batadv_socket_client *socket_client = file->private_data;
 180         struct batadv_priv *bat_priv = socket_client->bat_priv;
 181         struct batadv_hard_iface *primary_if = NULL;
 182         struct sk_buff *skb;
 183         struct batadv_icmp_packet_rr *icmp_packet_rr;
 184         struct batadv_icmp_header *icmp_header;
 185         struct batadv_orig_node *orig_node = NULL;
 186         struct batadv_neigh_node *neigh_node = NULL;
 187         size_t packet_len = sizeof(struct batadv_icmp_packet);
 188         u8 *addr;
 189
 190         if (len < sizeof(struct batadv_icmp_header)) {
 191                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 192                            "Error - can't send packet from char device: invalid packet size\n");
 193                 return -EINVAL;
 194         }
 195
 196         primary_if = batadv_primary_if_get_selected(bat_priv);
 197
 198         if (!primary_if) {
 199                 len = -EFAULT;
 200                 goto out;
 201         }
 202
 203         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 204                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 205         else
 206                 packet_len = len;
 207
 208         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 209         if (!skb) {
 210                 len = -ENOMEM;
 211                 goto out;
 212         }
 213
 214         skb->priority = TC_PRIO_CONTROL;
 215         skb_reserve(skb, ETH_HLEN);
 216         icmp_header = skb_put(skb, packet_len);
 217
 218         if (copy_from_user(icmp_header, buff, packet_len)) {
 219                 len = -EFAULT;
 220                 goto free_skb;
 221         }
 222
 223         if (icmp_header->packet_type != BATADV_ICMP) {
 224                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 225                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 226                 len = -EINVAL;
 227                 goto free_skb;
 228         }
 229
 230         switch (icmp_header->msg_type) {
 231         case BATADV_ECHO_REQUEST:
 232                 if (len < sizeof(struct batadv_icmp_packet)) {
 233                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 234                                    "Error - can't send packet from char device: invalid packet size\n");
 235                         len = -EINVAL;
 236                         goto free_skb;
 237                 }
 238
 239                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 240                         goto dst_unreach;
 241
 242                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 243                 if (!orig_node)
 244                         goto dst_unreach;
 245
 246                 neigh_node = batadv_orig_router_get(orig_node,
 247                                                     BATADV_IF_DEFAULT);
 248                 if (!neigh_node)
 249                         goto dst_unreach;
 250
 251                 if (!neigh_node->if_incoming)
 252                         goto dst_unreach;
 253
 254                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 255                         goto dst_unreach;
 256
 257                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 258                 if (packet_len == sizeof(*icmp_packet_rr)) {
 259                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 260                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 261                 }
 262
 263                 break;
 264         default:
 265                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 266                            "Error - can't send packet from char device: got unknown message type\n");
 267                 len = -EINVAL;
 268                 goto free_skb;
 269         }
 270
 271         icmp_header->uid = socket_client->index;
 272
 273         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 274                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 275                 icmp_header->version = BATADV_COMPAT_VERSION;
 276                 batadv_socket_add_packet(socket_client, icmp_header,
 277                                          packet_len);
 278                 goto free_skb;
 279         }
 280
 281         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 282
 283         batadv_send_unicast_skb(skb, neigh_node);
 284         goto out;
 285
 286 dst_unreach:
 287         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 288         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 289 free_skb:
 290         kfree_skb(skb);
 291 out:
 292         if (primary_if)
 293                 batadv_hardif_put(primary_if);
 294         if (neigh_node)
 295                 batadv_neigh_node_put(neigh_node);
 296         if (orig_node)
 297                 batadv_orig_node_put(orig_node);
 298         return len;
 299 }
 300
 301 static __poll_t batadv_socket_poll(struct file *file, poll_table *wait)
 302 {
 303         struct batadv_socket_client *socket_client = file->private_data;
 304
 305         poll_wait(file, &socket_client->queue_wait, wait);
 306
 307         if (socket_client->queue_len > 0)
 308                 return EPOLLIN | EPOLLRDNORM;
 309
 310         return 0;
 311 }
 312
 313 static const struct file_operations batadv_fops = {
 314         .owner = THIS_MODULE,
 315         .open = batadv_socket_open,
 316         .release = batadv_socket_release,
 317         .read = batadv_socket_read,
 318         .write = batadv_socket_write,
 319         .poll = batadv_socket_poll,
 320         .llseek = no_llseek,
 321 };
 322
 323 /**
 324  * batadv_socket_setup() - Create debugfs "socket" file
 325  * @bat_priv: the bat priv with all the soft interface information
 326  *
 327  * Return: 0 on success or negative error number in case of failure
 328  */
 329 int batadv_socket_setup(struct batadv_priv *bat_priv)
 330 {
 331         struct dentry *d;
 332
 333         if (!bat_priv->debug_dir)
 334                 goto err;
 335
 336         d = debugfs_create_file(BATADV_ICMP_SOCKET, 0600, bat_priv->debug_dir,
 337                                 bat_priv, &batadv_fops);
 338         if (!d)
 339                 goto err;
 340
 341         return 0;
 342
 343 err:
 344         return -ENOMEM;
 345 }
 346
 347 /**
 348  * batadv_socket_add_packet() - schedule an icmp packet to be sent to
 349  *  userspace on an icmp socket.
 350  * @socket_client: the socket this packet belongs to
 351  * @icmph: pointer to the header of the icmp packet
 352  * @icmp_len: total length of the icmp packet
 353  */
 354 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 355                                      struct batadv_icmp_header *icmph,
 356                                      size_t icmp_len)
 357 {
 358         struct batadv_socket_packet *socket_packet;
 359         size_t len;
 360
 361         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 362
 363         if (!socket_packet)
 364                 return;
 365
 366         len = icmp_len;
 367         /* check the maximum length before filling the buffer */
 368         if (len > sizeof(socket_packet->icmp_packet))
 369                 len = sizeof(socket_packet->icmp_packet);
 370
 371         INIT_LIST_HEAD(&socket_packet->list);
 372         memcpy(&socket_packet->icmp_packet, icmph, len);
 373         socket_packet->icmp_len = len;
 374
 375         spin_lock_bh(&socket_client->lock);
 376
 377         /* while waiting for the lock the socket_client could have been
 378          * deleted
 379          */
 380         if (!batadv_socket_client_hash[icmph->uid]) {
 381                 spin_unlock_bh(&socket_client->lock);
 382                 kfree(socket_packet);
 383                 return;
 384         }
 385
 386         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 387         socket_client->queue_len++;
 388
 389         if (socket_client->queue_len > 100) {
 390                 socket_packet = list_first_entry(&socket_client->queue_list,
 391                                                  struct batadv_socket_packet,
 392                                                  list);
 393
 394                 list_del(&socket_packet->list);
 395                 kfree(socket_packet);
 396                 socket_client->queue_len--;
 397         }
 398
 399         spin_unlock_bh(&socket_client->lock);
 400
 401         wake_up(&socket_client->queue_wait);
 402 }
 403
 404 /**
 405  * batadv_socket_receive_packet() - schedule an icmp packet to be received
 406  *  locally and sent to userspace.
 407  * @icmph: pointer to the header of the icmp packet
 408  * @icmp_len: total length of the icmp packet
 409  */
 410 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 411                                   size_t icmp_len)
 412 {
 413         struct batadv_socket_client *hash;
 414
 415         hash = batadv_socket_client_hash[icmph->uid];
 416         if (hash)
 417                 batadv_socket_add_packet(hash, icmph, icmp_len);
 418 }