drivers/net/wan/lapbether.c

   1 /*
   2  *      "LAPB via ethernet" driver release 001
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      This is a "pseudo" network driver to allow LAPB over Ethernet.
  13  *
  14  *      This driver can use any ethernet destination address, and can be
  15  *      limited to accept frames from one dedicated ethernet card only.
  16  *
  17  *      History
  18  *      LAPBETH 001     Jonathan Naylor         Cloned from bpqether.c
  19  *      2000-10-29      Henner Eisen    lapb_data_indication() return status.
  20  *      2000-11-14      Henner Eisen    dev_hold/put, NETDEV_GOING_DOWN support
  21  */
  22
  23 #include <linux/errno.h>
  24 #include <linux/types.h>
  25 #include <linux/socket.h>
  26 #include <linux/in.h>
  27 #include <linux/kernel.h>
  28 #include <linux/string.h>
  29 #include <linux/net.h>
  30 #include <linux/inet.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/skbuff.h>
  34 #include <net/sock.h>
  35 #include <asm/system.h>
  36 #include <asm/uaccess.h>
  37 #include <linux/mm.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/notifier.h>
  40 #include <linux/stat.h>
  41 #include <linux/netfilter.h>
  42 #include <linux/module.h>
  43 #include <linux/lapb.h>
  44 #include <linux/init.h>
  45
  46 static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
  47
  48 /* If this number is made larger, check that the temporary string buffer
  49  * in lapbeth_new_device is large enough to store the probe device name.*/
  50 #define MAXLAPBDEV 100
  51
  52 struct lapbethdev {
  53         struct list_head        node;
  54         struct net_device       *ethdev;        /* link to ethernet device */
  55         struct net_device       *axdev;         /* lapbeth device (lapb#) */
  56         struct net_device_stats stats;          /* some statistics */
  57 };
  58
  59 static struct list_head lapbeth_devices = LIST_HEAD_INIT(lapbeth_devices);
  60
  61 /* ------------------------------------------------------------------------ */
  62
  63 /*
  64  *      Get the LAPB device for the ethernet device
  65  */
  66 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
  67 {
  68         struct lapbethdev *lapbeth;
  69
  70         list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) {
  71                 if (lapbeth->ethdev == dev)
  72                         return lapbeth;
  73         }
  74         return NULL;
  75 }
  76
  77 static __inline__ int dev_is_ethdev(struct net_device *dev)
  78 {
  79         return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
  80 }
  81
  82 /* ------------------------------------------------------------------------ */
  83
  84 /*
  85  *      Receive a LAPB frame via an ethernet interface.
  86  */
  87 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
  88 {
  89         int len, err;
  90         struct lapbethdev *lapbeth;
  91
  92         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
  93                 return NET_RX_DROP;
  94
  95         if (!pskb_may_pull(skb, 2))
  96                 goto drop;
  97
  98         rcu_read_lock();
  99         lapbeth = lapbeth_get_x25_dev(dev);
 100         if (!lapbeth)
 101                 goto drop_unlock;
 102         if (!netif_running(lapbeth->axdev))
 103                 goto drop_unlock;
 104
 105         lapbeth->stats.rx_packets++;
 106
 107         len = skb->data[0] + skb->data[1] * 256;
 108         lapbeth->stats.rx_bytes += len;
 109
 110         skb_pull(skb, 2);       /* Remove the length bytes */
 111         skb_trim(skb, len);     /* Set the length of the data */
 112
 113         if ((err = lapb_data_received(lapbeth, skb)) != LAPB_OK) {
 114                 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
 115                 goto drop_unlock;
 116         }
 117 out:
 118         rcu_read_unlock();
 119         return 0;
 120 drop_unlock:
 121         kfree_skb(skb);
 122         goto out;
 123 drop:
 124         kfree_skb(skb);
 125         return 0;
 126 }
 127
 128 static int lapbeth_data_indication(void *token, struct sk_buff *skb)
 129 {
 130         struct lapbethdev *lapbeth = (struct lapbethdev *)token;
 131         unsigned char *ptr;
 132
 133         skb_push(skb, 1);
 134
 135         if (skb_cow(skb, 1))
 136                 return NET_RX_DROP;
 137
 138         ptr  = skb->data;
 139         *ptr = 0x00;
 140
 141         skb->dev      = lapbeth->axdev;
 142         skb->protocol = htons(ETH_P_X25);
 143         skb->mac.raw  = skb->data;
 144         skb->pkt_type = PACKET_HOST;
 145
 146         skb->dev->last_rx = jiffies;
 147         return netif_rx(skb);
 148 }
 149
 150 /*
 151  *      Send a LAPB frame via an ethernet interface
 152  */
 153 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
 154 {
 155         struct lapbethdev *lapbeth = (struct lapbethdev *)dev->priv;
 156         int err = -ENODEV;
 157
 158         /*
 159          * Just to be *really* sure not to send anything if the interface
 160          * is down, the ethernet device may have gone.
 161          */
 162         if (!netif_running(dev)) {
 163                 goto drop;
 164         }
 165
 166         switch (skb->data[0]) {
 167         case 0x00:
 168                 err = 0;
 169                 break;
 170         case 0x01:
 171                 if ((err = lapb_connect_request(lapbeth)) != LAPB_OK)
 172                         printk(KERN_ERR "lapbeth: lapb_connect_request "
 173                                "error: %d\n", err);
 174                 goto drop_ok;
 175         case 0x02:
 176                 if ((err = lapb_disconnect_request(lapbeth)) != LAPB_OK)
 177                         printk(KERN_ERR "lapbeth: lapb_disconnect_request "
 178                                "err: %d\n", err);
 179                 /* Fall thru */
 180         default:
 181                 goto drop_ok;
 182         }
 183
 184         skb_pull(skb, 1);
 185
 186         if ((err = lapb_data_request(lapbeth, skb)) != LAPB_OK) {
 187                 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
 188                 err = -ENOMEM;
 189                 goto drop;
 190         }
 191         err = 0;
 192 out:
 193         return err;
 194 drop_ok:
 195         err = 0;
 196 drop:
 197         kfree_skb(skb);
 198         goto out;
 199 }
 200
 201 static void lapbeth_data_transmit(void *token, struct sk_buff *skb)
 202 {
 203         struct lapbethdev *lapbeth = (struct lapbethdev *)token;
 204         unsigned char *ptr;
 205         struct net_device *dev;
 206         int size = skb->len;
 207
 208         skb->protocol = htons(ETH_P_X25);
 209
 210         ptr = skb_push(skb, 2);
 211
 212         *ptr++ = size % 256;
 213         *ptr++ = size / 256;
 214
 215         lapbeth->stats.tx_packets++;
 216         lapbeth->stats.tx_bytes += size;
 217
 218         skb->dev = dev = lapbeth->ethdev;
 219
 220         dev->hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
 221
 222         dev_queue_xmit(skb);
 223 }
 224
 225 static void lapbeth_connected(void *token, int reason)
 226 {
 227         struct lapbethdev *lapbeth = (struct lapbethdev *)token;
 228         unsigned char *ptr;
 229         struct sk_buff *skb = dev_alloc_skb(1);
 230
 231         if (!skb) {
 232                 printk(KERN_ERR "lapbeth: out of memory\n");
 233                 return;
 234         }
 235
 236         ptr  = skb_put(skb, 1);
 237         *ptr = 0x01;
 238
 239         skb->dev      = lapbeth->axdev;
 240         skb->protocol = htons(ETH_P_X25);
 241         skb->mac.raw  = skb->data;
 242         skb->pkt_type = PACKET_HOST;
 243
 244         skb->dev->last_rx = jiffies;
 245         netif_rx(skb);
 246 }
 247
 248 static void lapbeth_disconnected(void *token, int reason)
 249 {
 250         struct lapbethdev *lapbeth = (struct lapbethdev *)token;
 251         unsigned char *ptr;
 252         struct sk_buff *skb = dev_alloc_skb(1);
 253
 254         if (!skb) {
 255                 printk(KERN_ERR "lapbeth: out of memory\n");
 256                 return;
 257         }
 258
 259         ptr  = skb_put(skb, 1);
 260         *ptr = 0x02;
 261
 262         skb->dev      = lapbeth->axdev;
 263         skb->protocol = htons(ETH_P_X25);
 264         skb->mac.raw  = skb->data;
 265         skb->pkt_type = PACKET_HOST;
 266
 267         skb->dev->last_rx = jiffies;
 268         netif_rx(skb);
 269 }
 270
 271 /*
 272  *      Statistics
 273  */
 274 static struct net_device_stats *lapbeth_get_stats(struct net_device *dev)
 275 {
 276         struct lapbethdev *lapbeth = (struct lapbethdev *)dev->priv;
 277         return &lapbeth->stats;
 278 }
 279
 280 /*
 281  *      Set AX.25 callsign
 282  */
 283 static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
 284 {
 285         struct sockaddr *sa = (struct sockaddr *)addr;
 286         memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 287         return 0;
 288 }
 289
 290
 291 static struct lapb_register_struct lapbeth_callbacks = {
 292         .connect_confirmation    = lapbeth_connected,
 293         .connect_indication      = lapbeth_connected,
 294         .disconnect_confirmation = lapbeth_disconnected,
 295         .disconnect_indication   = lapbeth_disconnected,
 296         .data_indication         = lapbeth_data_indication,
 297         .data_transmit           = lapbeth_data_transmit,
 298
 299 };
 300
 301 /*
 302  * open/close a device
 303  */
 304 static int lapbeth_open(struct net_device *dev)
 305 {
 306         struct lapbethdev *lapbeth;
 307         int err;
 308
 309         lapbeth = (struct lapbethdev *)dev->priv;
 310         if ((err = lapb_register(lapbeth, &lapbeth_callbacks)) != LAPB_OK) {
 311                 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
 312                 return -ENODEV;
 313         }
 314
 315         netif_start_queue(dev);
 316         return 0;
 317 }
 318
 319 static int lapbeth_close(struct net_device *dev)
 320 {
 321         struct lapbethdev *lapbeth = (struct lapbethdev *)dev->priv;
 322         int err;
 323
 324         netif_stop_queue(dev);
 325
 326         if ((err = lapb_unregister(lapbeth)) != LAPB_OK)
 327                 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
 328
 329         return 0;
 330 }
 331
 332 /* ------------------------------------------------------------------------ */
 333
 334 static void lapbeth_setup(struct net_device *dev)
 335 {
 336         dev->hard_start_xmit = lapbeth_xmit;
 337         dev->open            = lapbeth_open;
 338         dev->stop            = lapbeth_close;
 339         dev->destructor      = free_netdev;
 340         dev->set_mac_address = lapbeth_set_mac_address;
 341         dev->get_stats       = lapbeth_get_stats;
 342         dev->type            = ARPHRD_X25;
 343         dev->hard_header_len = 3;
 344         dev->mtu             = 1000;
 345         dev->addr_len        = 0;
 346         SET_MODULE_OWNER(dev);
 347 }
 348
 349 /*
 350  *      Setup a new device.
 351  */
 352 static int lapbeth_new_device(struct net_device *dev)
 353 {
 354         struct net_device *ndev;
 355         struct lapbethdev *lapbeth;
 356         int rc = -ENOMEM;
 357
 358         ASSERT_RTNL();
 359
 360         ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
 361                            lapbeth_setup);
 362         if (!ndev)
 363                 goto out;
 364
 365         lapbeth = ndev->priv;
 366         lapbeth->axdev = ndev;
 367
 368         dev_hold(dev);
 369         lapbeth->ethdev = dev;
 370
 371         rc = dev_alloc_name(ndev, ndev->name);
 372         if (rc < 0)
 373                 goto fail;
 374
 375         rc = -EIO;
 376         if (register_netdevice(ndev))
 377                 goto fail;
 378
 379         list_add_rcu(&lapbeth->node, &lapbeth_devices);
 380         rc = 0;
 381 out:
 382         return rc;
 383 fail:
 384         dev_put(dev);
 385         kfree(lapbeth);
 386         goto out;
 387 }
 388
 389 /*
 390  *      Free a lapb network device.
 391  */
 392 static void lapbeth_free_device(struct lapbethdev *lapbeth)
 393 {
 394         dev_put(lapbeth->ethdev);
 395         list_del_rcu(&lapbeth->node);
 396         unregister_netdevice(lapbeth->axdev);
 397 }
 398
 399 /*
 400  *      Handle device status changes.
 401  */
 402 static int lapbeth_device_event(struct notifier_block *this,
 403                                 unsigned long event, void *ptr)
 404 {
 405         struct lapbethdev *lapbeth;
 406         struct net_device *dev = (struct net_device *)ptr;
 407
 408         if (!dev_is_ethdev(dev))
 409                 return NOTIFY_DONE;
 410
 411         rcu_read_lock();
 412         switch (event) {
 413         case NETDEV_UP:
 414                 /* New ethernet device -> new LAPB interface     */
 415                 if (lapbeth_get_x25_dev(dev) == NULL)
 416                         lapbeth_new_device(dev);
 417                 break;
 418         case NETDEV_DOWN:
 419                 /* ethernet device closed -> close LAPB interface */
 420                 lapbeth = lapbeth_get_x25_dev(dev);
 421                 if (lapbeth)
 422                         dev_close(lapbeth->axdev);
 423                 break;
 424         case NETDEV_UNREGISTER:
 425                 /* ethernet device disappears -> remove LAPB interface */
 426                 lapbeth = lapbeth_get_x25_dev(dev);
 427                 if (lapbeth)
 428                         lapbeth_free_device(lapbeth);
 429                 break;
 430         }
 431         rcu_read_unlock();
 432
 433         return NOTIFY_DONE;
 434 }
 435
 436 /* ------------------------------------------------------------------------ */
 437
 438 static struct packet_type lapbeth_packet_type = {
 439         .type = __constant_htons(ETH_P_DEC),
 440         .func = lapbeth_rcv,
 441 };
 442
 443 static struct notifier_block lapbeth_dev_notifier = {
 444         .notifier_call = lapbeth_device_event,
 445 };
 446
 447 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n";
 448
 449 static int __init lapbeth_init_driver(void)
 450 {
 451         dev_add_pack(&lapbeth_packet_type);
 452
 453         register_netdevice_notifier(&lapbeth_dev_notifier);
 454
 455         printk(banner);
 456
 457         return 0;
 458 }
 459 module_init(lapbeth_init_driver);
 460
 461 static void __exit lapbeth_cleanup_driver(void)
 462 {
 463         struct lapbethdev *lapbeth;
 464         struct list_head *entry, *tmp;
 465
 466         dev_remove_pack(&lapbeth_packet_type);
 467         unregister_netdevice_notifier(&lapbeth_dev_notifier);
 468
 469         rtnl_lock();
 470         list_for_each_safe(entry, tmp, &lapbeth_devices) {
 471                 lapbeth = list_entry(entry, struct lapbethdev, node);
 472
 473                 unregister_netdevice(lapbeth->axdev);
 474         }
 475         rtnl_unlock();
 476 }
 477 module_exit(lapbeth_cleanup_driver);
 478
 479 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 480 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
 481 MODULE_LICENSE("GPL");