linux/net/batman-adv/icmp_socket.c
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   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
  44static struct batadv_socket_client *batadv_socket_client_hash[256];
  45
  46static 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 */
  53void batadv_socket_init(void)
  54{
  55        memset(batadv_socket_client_hash, 0, sizeof(batadv_socket_client_hash));
  56}
  57
  58static 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
 102static 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
 124static 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
 164static 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
 274dst_unreach:
 275        icmp_header->msg_type = BATADV_DESTINATION_UNREACHABLE;
 276        batadv_socket_add_packet(socket_client, icmp_header, packet_len);
 277free_skb:
 278        kfree_skb(skb);
 279out:
 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
 289static __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
 301static 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 */
 315void 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 */
 328static 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 */
 384void 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}
 393