net/batman-adv/icmp_socket.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2007-2019  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 "debugfs.h"
  51 #include "hard-interface.h"
  52 #include "log.h"
  53 #include "originator.h"
  54 #include "send.h"
  55
  56 static struct batadv_socket_client *batadv_socket_client_hash[256];
  57
  58 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  59                                      struct batadv_icmp_header *icmph,
  60                                      size_t icmp_len);
  61
  62 /**
  63  * batadv_socket_init() - Initialize soft interface independent socket data
  64  */
  65 void batadv_socket_init(void)
  66 {
  67         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  68 }
  69
  70 static int batadv_socket_open(struct inode *inode, struct file *file)
  71 {
  72         unsigned int i;
  73         struct batadv_socket_client *socket_client;
  74
  75         if (!try_module_get(THIS_MODULE))
  76                 return -EBUSY;
  77
  78         batadv_debugfs_deprecated(file, "");
  79
  80         nonseekable_open(inode, file);
  81
  82         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  83         if (!socket_client) {
  84                 module_put(THIS_MODULE);
  85                 return -ENOMEM;
  86         }
  87
  88         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  89                 if (!batadv_socket_client_hash[i]) {
  90                         batadv_socket_client_hash[i] = socket_client;
  91                         break;
  92                 }
  93         }
  94
  95         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  96                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  97                 kfree(socket_client);
  98                 module_put(THIS_MODULE);
  99                 return -EXFULL;
 100         }
 101
 102         INIT_LIST_HEAD(&socket_client->queue_list);
 103         socket_client->queue_len = 0;
 104         socket_client->index = i;
 105         socket_client->bat_priv = inode->i_private;
 106         spin_lock_init(&socket_client->lock);
 107         init_waitqueue_head(&socket_client->queue_wait);
 108
 109         file->private_data = socket_client;
 110
 111         return 0;
 112 }
 113
 114 static int batadv_socket_release(struct inode *inode, struct file *file)
 115 {
 116         struct batadv_socket_client *client = file->private_data;
 117         struct batadv_socket_packet *packet, *tmp;
 118
 119         spin_lock_bh(&client->lock);
 120
 121         /* for all packets in the queue ... */
 122         list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
 123                 list_del(&packet->list);
 124                 kfree(packet);
 125         }
 126
 127         batadv_socket_client_hash[client->index] = NULL;
 128         spin_unlock_bh(&client->lock);
 129
 130         kfree(client);
 131         module_put(THIS_MODULE);
 132
 133         return 0;
 134 }
 135
 136 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 137                                   size_t count, loff_t *ppos)
 138 {
 139         struct batadv_socket_client *socket_client = file->private_data;
 140         struct batadv_socket_packet *socket_packet;
 141         size_t packet_len;
 142         int error;
 143
 144         if ((file->f_flags & O_NONBLOCK) && socket_client->queue_len == 0)
 145                 return -EAGAIN;
 146
 147         if (!buf || count < sizeof(struct batadv_icmp_packet))
 148                 return -EINVAL;
 149
 150         if (!access_ok(buf, count))
 151                 return -EFAULT;
 152
 153         error = wait_event_interruptible(socket_client->queue_wait,
 154                                          socket_client->queue_len);
 155
 156         if (error)
 157                 return error;
 158
 159         spin_lock_bh(&socket_client->lock);
 160
 161         socket_packet = list_first_entry(&socket_client->queue_list,
 162                                          struct batadv_socket_packet, list);
 163         list_del(&socket_packet->list);
 164         socket_client->queue_len--;
 165
 166         spin_unlock_bh(&socket_client->lock);
 167
 168         packet_len = min(count, socket_packet->icmp_len);
 169         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 170
 171         kfree(socket_packet);
 172
 173         if (error)
 174                 return -EFAULT;
 175
 176         return packet_len;
 177 }
 178
 179 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 180                                    size_t len, loff_t *off)
 181 {
 182         struct batadv_socket_client *socket_client = file->private_data;
 183         struct batadv_priv *bat_priv = socket_client->bat_priv;
 184         struct batadv_hard_iface *primary_if = NULL;
 185         struct sk_buff *skb;
 186         struct batadv_icmp_packet_rr *icmp_packet_rr;
 187         struct batadv_icmp_header *icmp_header;
 188         struct batadv_orig_node *orig_node = NULL;
 189         struct batadv_neigh_node *neigh_node = NULL;
 190         size_t packet_len = sizeof(struct batadv_icmp_packet);
 191         u8 *addr;
 192
 193         if (len < sizeof(struct batadv_icmp_header)) {
 194                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 195                            "Error - can't send packet from char device: invalid packet size\n");
 196                 return -EINVAL;
 197         }
 198
 199         primary_if = batadv_primary_if_get_selected(bat_priv);
 200
 201         if (!primary_if) {
 202                 len = -EFAULT;
 203                 goto out;
 204         }
 205
 206         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 207                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 208         else
 209                 packet_len = len;
 210
 211         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 212         if (!skb) {
 213                 len = -ENOMEM;
 214                 goto out;
 215         }
 216
 217         skb->priority = TC_PRIO_CONTROL;
 218         skb_reserve(skb, ETH_HLEN);
 219         icmp_header = skb_put(skb, packet_len);
 220
 221         if (copy_from_user(icmp_header, buff, packet_len)) {
 222                 len = -EFAULT;
 223                 goto free_skb;
 224         }
 225
 226         if (icmp_header->packet_type != BATADV_ICMP) {
 227                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 228                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 229                 len = -EINVAL;
 230                 goto free_skb;
 231         }
 232
 233         switch (icmp_header->msg_type) {
 234         case BATADV_ECHO_REQUEST:
 235                 if (len < sizeof(struct batadv_icmp_packet)) {
 236                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 237                                    "Error - can't send packet from char device: invalid packet size\n");
 238                         len = -EINVAL;
 239                         goto free_skb;
 240                 }
 241
 242                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 243                         goto dst_unreach;
 244
 245                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 246                 if (!orig_node)
 247                         goto dst_unreach;
 248
 249                 neigh_node = batadv_orig_router_get(orig_node,
 250                                                     BATADV_IF_DEFAULT);
 251                 if (!neigh_node)
 252                         goto dst_unreach;
 253
 254                 if (!neigh_node->if_incoming)
 255                         goto dst_unreach;
 256
 257                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 258                         goto dst_unreach;
 259
 260                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 261                 if (packet_len == sizeof(*icmp_packet_rr)) {
 262                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 263                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 264                 }
 265
 266                 break;
 267         default:
 268                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 269                            "Error - can't send packet from char device: got unknown message type\n");
 270                 len = -EINVAL;
 271                 goto free_skb;
 272         }
 273
 274         icmp_header->uid = socket_client->index;
 275
 276         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 277                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 278                 icmp_header->version = BATADV_COMPAT_VERSION;
 279                 batadv_socket_add_packet(socket_client, icmp_header,
 280                                          packet_len);
 281                 goto free_skb;
 282         }
 283
 284         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 285
 286         batadv_send_unicast_skb(skb, neigh_node);
 287         goto out;
 288
 289 dst_unreach:
 290         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 291         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 292 free_skb:
 293         kfree_skb(skb);
 294 out:
 295         if (primary_if)
 296                 batadv_hardif_put(primary_if);
 297         if (neigh_node)
 298                 batadv_neigh_node_put(neigh_node);
 299         if (orig_node)
 300                 batadv_orig_node_put(orig_node);
 301         return len;
 302 }
 303
 304 static __poll_t batadv_socket_poll(struct file *file, poll_table *wait)
 305 {
 306         struct batadv_socket_client *socket_client = file->private_data;
 307
 308         poll_wait(file, &socket_client->queue_wait, wait);
 309
 310         if (socket_client->queue_len > 0)
 311                 return EPOLLIN | EPOLLRDNORM;
 312
 313         return 0;
 314 }
 315
 316 static const struct file_operations batadv_fops = {
 317         .owner = THIS_MODULE,
 318         .open = batadv_socket_open,
 319         .release = batadv_socket_release,
 320         .read = batadv_socket_read,
 321         .write = batadv_socket_write,
 322         .poll = batadv_socket_poll,
 323         .llseek = no_llseek,
 324 };
 325
 326 /**
 327  * batadv_socket_setup() - Create debugfs "socket" file
 328  * @bat_priv: the bat priv with all the soft interface information
 329  *
 330  * Return: 0 on success or negative error number in case of failure
 331  */
 332 int batadv_socket_setup(struct batadv_priv *bat_priv)
 333 {
 334         struct dentry *d;
 335
 336         if (!bat_priv->debug_dir)
 337                 goto err;
 338
 339         d = debugfs_create_file(BATADV_ICMP_SOCKET, 0600, bat_priv->debug_dir,
 340                                 bat_priv, &batadv_fops);
 341         if (!d)
 342                 goto err;
 343
 344         return 0;
 345
 346 err:
 347         return -ENOMEM;
 348 }
 349
 350 /**
 351  * batadv_socket_add_packet() - schedule an icmp packet to be sent to
 352  *  userspace on an icmp socket.
 353  * @socket_client: the socket this packet belongs to
 354  * @icmph: pointer to the header of the icmp packet
 355  * @icmp_len: total length of the icmp packet
 356  */
 357 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 358                                      struct batadv_icmp_header *icmph,
 359                                      size_t icmp_len)
 360 {
 361         struct batadv_socket_packet *socket_packet;
 362         size_t len;
 363
 364         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 365
 366         if (!socket_packet)
 367                 return;
 368
 369         len = icmp_len;
 370         /* check the maximum length before filling the buffer */
 371         if (len > sizeof(socket_packet->icmp_packet))
 372                 len = sizeof(socket_packet->icmp_packet);
 373
 374         INIT_LIST_HEAD(&socket_packet->list);
 375         memcpy(&socket_packet->icmp_packet, icmph, len);
 376         socket_packet->icmp_len = len;
 377
 378         spin_lock_bh(&socket_client->lock);
 379
 380         /* while waiting for the lock the socket_client could have been
 381          * deleted
 382          */
 383         if (!batadv_socket_client_hash[icmph->uid]) {
 384                 spin_unlock_bh(&socket_client->lock);
 385                 kfree(socket_packet);
 386                 return;
 387         }
 388
 389         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 390         socket_client->queue_len++;
 391
 392         if (socket_client->queue_len > 100) {
 393                 socket_packet = list_first_entry(&socket_client->queue_list,
 394                                                  struct batadv_socket_packet,
 395                                                  list);
 396
 397                 list_del(&socket_packet->list);
 398                 kfree(socket_packet);
 399                 socket_client->queue_len--;
 400         }
 401
 402         spin_unlock_bh(&socket_client->lock);
 403
 404         wake_up(&socket_client->queue_wait);
 405 }
 406
 407 /**
 408  * batadv_socket_receive_packet() - schedule an icmp packet to be received
 409  *  locally and sent to userspace.
 410  * @icmph: pointer to the header of the icmp packet
 411  * @icmp_len: total length of the icmp packet
 412  */
 413 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 414                                   size_t icmp_len)
 415 {
 416         struct batadv_socket_client *hash;
 417
 418         hash = batadv_socket_client_hash[icmph->uid];
 419         if (hash)
 420                 batadv_socket_add_packet(hash, icmph, icmp_len);
 421 }