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