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