net/batman-adv/icmp_socket.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2007-2020  B.A.T.M.A.N. contributors:
   3  *
   4  * Marek Lindner
   5  */
   6
   7 #include "icmp_socket.h"
   8 #include "main.h"
   9
  10 #include <linux/atomic.h>
  11 #include <linux/compiler.h>
  12 #include <linux/debugfs.h>
  13 #include <linux/errno.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/eventpoll.h>
  16 #include <linux/export.h>
  17 #include <linux/fcntl.h>
  18 #include <linux/fs.h>
  19 #include <linux/gfp.h>
  20 #include <linux/if_ether.h>
  21 #include <linux/kernel.h>
  22 #include <linux/list.h>
  23 #include <linux/module.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/pkt_sched.h>
  26 #include <linux/poll.h>
  27 #include <linux/printk.h>
  28 #include <linux/sched.h> /* for linux/wait.h */
  29 #include <linux/skbuff.h>
  30 #include <linux/slab.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/stddef.h>
  33 #include <linux/string.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/wait.h>
  36 #include <uapi/linux/batadv_packet.h>
  37
  38 #include "debugfs.h"
  39 #include "hard-interface.h"
  40 #include "log.h"
  41 #include "originator.h"
  42 #include "send.h"
  43
  44 static struct batadv_socket_client *batadv_socket_client_hash[256];
  45
  46 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
  47                                      struct batadv_icmp_header *icmph,
  48                                      size_t icmp_len);
  49
  50 /**
  51  * batadv_socket_init() - Initialize soft interface independent socket data
  52  */
  53 void batadv_socket_init(void)
  54 {
  55         memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  56 }
  57
  58 static int batadv_socket_open(struct inode *inode, struct file *file)
  59 {
  60         unsigned int i;
  61         struct batadv_socket_client *socket_client;
  62
  63         if (!try_module_get(THIS_MODULE))
  64                 return -EBUSY;
  65
  66         batadv_debugfs_deprecated(file, "");
  67
  68         stream_open(inode, file);
  69
  70         socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
  71         if (!socket_client) {
  72                 module_put(THIS_MODULE);
  73                 return -ENOMEM;
  74         }
  75
  76         for (i = 0; i < ARRAY_SIZE(batadv_socket_client_hash); i++) {
  77                 if (!batadv_socket_client_hash[i]) {
  78                         batadv_socket_client_hash[i] = socket_client;
  79                         break;
  80                 }
  81         }
  82
  83         if (i == ARRAY_SIZE(batadv_socket_client_hash)) {
  84                 pr_err("Error - can't add another packet client: maximum number of clients reached\n");
  85                 kfree(socket_client);
  86                 module_put(THIS_MODULE);
  87                 return -EXFULL;
  88         }
  89
  90         INIT_LIST_HEAD(&socket_client->queue_list);
  91         socket_client->queue_len = 0;
  92         socket_client->index = i;
  93         socket_client->bat_priv = inode->i_private;
  94         spin_lock_init(&socket_client->lock);
  95         init_waitqueue_head(&socket_client->queue_wait);
  96
  97         file->private_data = socket_client;
  98
  99         return 0;
 100 }
 101
 102 static int batadv_socket_release(struct inode *inode, struct file *file)
 103 {
 104         struct batadv_socket_client *client = file->private_data;
 105         struct batadv_socket_packet *packet, *tmp;
 106
 107         spin_lock_bh(&client->lock);
 108
 109         /* for all packets in the queue ... */
 110         list_for_each_entry_safe(packet, tmp, &client->queue_list, list) {
 111                 list_del(&packet->list);
 112                 kfree(packet);
 113         }
 114
 115         batadv_socket_client_hash[client->index] = NULL;
 116         spin_unlock_bh(&client->lock);
 117
 118         kfree(client);
 119         module_put(THIS_MODULE);
 120
 121         return 0;
 122 }
 123
 124 static ssize_t batadv_socket_read(struct file *file, char __user *buf,
 125                                   size_t count, loff_t *ppos)
 126 {
 127         struct batadv_socket_client *socket_client = file->private_data;
 128         struct batadv_socket_packet *socket_packet;
 129         size_t packet_len;
 130         int error;
 131
 132         if ((file->f_flags & O_NONBLOCK) && socket_client->queue_len == 0)
 133                 return -EAGAIN;
 134
 135         if (!buf || count < sizeof(struct batadv_icmp_packet))
 136                 return -EINVAL;
 137
 138         error = wait_event_interruptible(socket_client->queue_wait,
 139                                          socket_client->queue_len);
 140
 141         if (error)
 142                 return error;
 143
 144         spin_lock_bh(&socket_client->lock);
 145
 146         socket_packet = list_first_entry(&socket_client->queue_list,
 147                                          struct batadv_socket_packet, list);
 148         list_del(&socket_packet->list);
 149         socket_client->queue_len--;
 150
 151         spin_unlock_bh(&socket_client->lock);
 152
 153         packet_len = min(count, socket_packet->icmp_len);
 154         error = copy_to_user(buf, &socket_packet->icmp_packet, packet_len);
 155
 156         kfree(socket_packet);
 157
 158         if (error)
 159                 return -EFAULT;
 160
 161         return packet_len;
 162 }
 163
 164 static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 165                                    size_t len, loff_t *off)
 166 {
 167         struct batadv_socket_client *socket_client = file->private_data;
 168         struct batadv_priv *bat_priv = socket_client->bat_priv;
 169         struct batadv_hard_iface *primary_if = NULL;
 170         struct sk_buff *skb;
 171         struct batadv_icmp_packet_rr *icmp_packet_rr;
 172         struct batadv_icmp_header *icmp_header;
 173         struct batadv_orig_node *orig_node = NULL;
 174         struct batadv_neigh_node *neigh_node = NULL;
 175         size_t packet_len = sizeof(struct batadv_icmp_packet);
 176         u8 *addr;
 177
 178         if (len < sizeof(struct batadv_icmp_header)) {
 179                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 180                            "Error - can't send packet from char device: invalid packet size\n");
 181                 return -EINVAL;
 182         }
 183
 184         primary_if = batadv_primary_if_get_selected(bat_priv);
 185
 186         if (!primary_if) {
 187                 len = -EFAULT;
 188                 goto out;
 189         }
 190
 191         if (len >= BATADV_ICMP_MAX_PACKET_SIZE)
 192                 packet_len = BATADV_ICMP_MAX_PACKET_SIZE;
 193         else
 194                 packet_len = len;
 195
 196         skb = netdev_alloc_skb_ip_align(NULL, packet_len + ETH_HLEN);
 197         if (!skb) {
 198                 len = -ENOMEM;
 199                 goto out;
 200         }
 201
 202         skb->priority = TC_PRIO_CONTROL;
 203         skb_reserve(skb, ETH_HLEN);
 204         icmp_header = skb_put(skb, packet_len);
 205
 206         if (copy_from_user(icmp_header, buff, packet_len)) {
 207                 len = -EFAULT;
 208                 goto free_skb;
 209         }
 210
 211         if (icmp_header->packet_type != BATADV_ICMP) {
 212                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 213                            "Error - can't send packet from char device: got bogus packet type (expected: BAT_ICMP)\n");
 214                 len = -EINVAL;
 215                 goto free_skb;
 216         }
 217
 218         switch (icmp_header->msg_type) {
 219         case BATADV_ECHO_REQUEST:
 220                 if (len < sizeof(struct batadv_icmp_packet)) {
 221                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 222                                    "Error - can't send packet from char device: invalid packet size\n");
 223                         len = -EINVAL;
 224                         goto free_skb;
 225                 }
 226
 227                 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 228                         goto dst_unreach;
 229
 230                 orig_node = batadv_orig_hash_find(bat_priv, icmp_header->dst);
 231                 if (!orig_node)
 232                         goto dst_unreach;
 233
 234                 neigh_node = batadv_orig_router_get(orig_node,
 235                                                     BATADV_IF_DEFAULT);
 236                 if (!neigh_node)
 237                         goto dst_unreach;
 238
 239                 if (!neigh_node->if_incoming)
 240                         goto dst_unreach;
 241
 242                 if (neigh_node->if_incoming->if_status != BATADV_IF_ACTIVE)
 243                         goto dst_unreach;
 244
 245                 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmp_header;
 246                 if (packet_len == sizeof(*icmp_packet_rr)) {
 247                         addr = neigh_node->if_incoming->net_dev->dev_addr;
 248                         ether_addr_copy(icmp_packet_rr->rr[0], addr);
 249                 }
 250
 251                 break;
 252         default:
 253                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 254                            "Error - can't send packet from char device: got unknown message type\n");
 255                 len = -EINVAL;
 256                 goto free_skb;
 257         }
 258
 259         icmp_header->uid = socket_client->index;
 260
 261         if (icmp_header->version != BATADV_COMPAT_VERSION) {
 262                 icmp_header->msg_type = BATADV_PARAMETER_PROBLEM;
 263                 icmp_header->version = BATADV_COMPAT_VERSION;
 264                 batadv_socket_add_packet(socket_client, icmp_header,
 265                                          packet_len);
 266                 goto free_skb;
 267         }
 268
 269         ether_addr_copy(icmp_header->orig, primary_if->net_dev->dev_addr);
 270
 271         batadv_send_unicast_skb(skb, neigh_node);
 272         goto out;
 273
 274 dst_unreach:
 275         icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 276         batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 277 free_skb:
 278         kfree_skb(skb);
 279 out:
 280         if (primary_if)
 281                 batadv_hardif_put(primary_if);
 282         if (neigh_node)
 283                 batadv_neigh_node_put(neigh_node);
 284         if (orig_node)
 285                 batadv_orig_node_put(orig_node);
 286         return len;
 287 }
 288
 289 static __poll_t batadv_socket_poll(struct file *file, poll_table *wait)
 290 {
 291         struct batadv_socket_client *socket_client = file->private_data;
 292
 293         poll_wait(file, &socket_client->queue_wait, wait);
 294
 295         if (socket_client->queue_len > 0)
 296                 return EPOLLIN | EPOLLRDNORM;
 297
 298         return 0;
 299 }
 300
 301 static const struct file_operations batadv_fops = {
 302         .owner = THIS_MODULE,
 303         .open = batadv_socket_open,
 304         .release = batadv_socket_release,
 305         .read = batadv_socket_read,
 306         .write = batadv_socket_write,
 307         .poll = batadv_socket_poll,
 308         .llseek = no_llseek,
 309 };
 310
 311 /**
 312  * batadv_socket_setup() - Create debugfs "socket" file
 313  * @bat_priv: the bat priv with all the soft interface information
 314  */
 315 void batadv_socket_setup(struct batadv_priv *bat_priv)
 316 {
 317         debugfs_create_file(BATADV_ICMP_SOCKET, 0600, bat_priv->debug_dir,
 318                             bat_priv, &batadv_fops);
 319 }
 320
 321 /**
 322  * batadv_socket_add_packet() - schedule an icmp packet to be sent to
 323  *  userspace on an icmp socket.
 324  * @socket_client: the socket this packet belongs to
 325  * @icmph: pointer to the header of the icmp packet
 326  * @icmp_len: total length of the icmp packet
 327  */
 328 static void batadv_socket_add_packet(struct batadv_socket_client *socket_client,
 329                                      struct batadv_icmp_header *icmph,
 330                                      size_t icmp_len)
 331 {
 332         struct batadv_socket_packet *socket_packet;
 333         size_t len;
 334
 335         socket_packet = kmalloc(sizeof(*socket_packet), GFP_ATOMIC);
 336
 337         if (!socket_packet)
 338                 return;
 339
 340         len = icmp_len;
 341         /* check the maximum length before filling the buffer */
 342         if (len > sizeof(socket_packet->icmp_packet))
 343                 len = sizeof(socket_packet->icmp_packet);
 344
 345         INIT_LIST_HEAD(&socket_packet->list);
 346         memcpy(&socket_packet->icmp_packet, icmph, len);
 347         socket_packet->icmp_len = len;
 348
 349         spin_lock_bh(&socket_client->lock);
 350
 351         /* while waiting for the lock the socket_client could have been
 352          * deleted
 353          */
 354         if (!batadv_socket_client_hash[icmph->uid]) {
 355                 spin_unlock_bh(&socket_client->lock);
 356                 kfree(socket_packet);
 357                 return;
 358         }
 359
 360         list_add_tail(&socket_packet->list, &socket_client->queue_list);
 361         socket_client->queue_len++;
 362
 363         if (socket_client->queue_len > 100) {
 364                 socket_packet = list_first_entry(&socket_client->queue_list,
 365                                                  struct batadv_socket_packet,
 366                                                  list);
 367
 368                 list_del(&socket_packet->list);
 369                 kfree(socket_packet);
 370                 socket_client->queue_len--;
 371         }
 372
 373         spin_unlock_bh(&socket_client->lock);
 374
 375         wake_up(&socket_client->queue_wait);
 376 }
 377
 378 /**
 379  * batadv_socket_receive_packet() - schedule an icmp packet to be received
 380  *  locally and sent to userspace.
 381  * @icmph: pointer to the header of the icmp packet
 382  * @icmp_len: total length of the icmp packet
 383  */
 384 void batadv_socket_receive_packet(struct batadv_icmp_header *icmph,
 385                                   size_t icmp_len)
 386 {
 387         struct batadv_socket_client *hash;
 388
 389         hash = batadv_socket_client_hash[icmph->uid];
 390         if (hash)
 391                 batadv_socket_add_packet(hash, icmph, icmp_len);
 392 }