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->axdev, 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(struct net_device *dev, struct sk_buff *skb)
 129 {
 130         unsigned char *ptr;
 131
 132         skb_push(skb, 1);
 133
 134         if (skb_cow(skb, 1))
 135                 return NET_RX_DROP;
 136
 137         ptr  = skb->data;
 138         *ptr = 0x00;
 139
 140         skb->dev      = dev;
 141         skb->protocol = htons(ETH_P_X25);
 142         skb->mac.raw  = skb->data;
 143         skb->pkt_type = PACKET_HOST;
 144
 145         skb->dev->last_rx = jiffies;
 146         return netif_rx(skb);
 147 }
 148
 149 /*
 150  *      Send a LAPB frame via an ethernet interface
 151  */
 152 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
 153 {
 154         int err = -ENODEV;
 155
 156         /*
 157          * Just to be *really* sure not to send anything if the interface
 158          * is down, the ethernet device may have gone.
 159          */
 160         if (!netif_running(dev)) {
 161                 goto drop;
 162         }
 163
 164         switch (skb->data[0]) {
 165         case 0x00:
 166                 err = 0;
 167                 break;
 168         case 0x01:
 169                 if ((err = lapb_connect_request(dev)) != LAPB_OK)
 170                         printk(KERN_ERR "lapbeth: lapb_connect_request "
 171                                "error: %d\n", err);
 172                 goto drop_ok;
 173         case 0x02:
 174                 if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
 175                         printk(KERN_ERR "lapbeth: lapb_disconnect_request "
 176                                "err: %d\n", err);
 177                 /* Fall thru */
 178         default:
 179                 goto drop_ok;
 180         }
 181
 182         skb_pull(skb, 1);
 183
 184         if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
 185                 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
 186                 err = -ENOMEM;
 187                 goto drop;
 188         }
 189         err = 0;
 190 out:
 191         return err;
 192 drop_ok:
 193         err = 0;
 194 drop:
 195         kfree_skb(skb);
 196         goto out;
 197 }
 198
 199 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
 200 {
 201         struct lapbethdev *lapbeth = netdev_priv(ndev);
 202         unsigned char *ptr;
 203         struct net_device *dev;
 204         int size = skb->len;
 205
 206         skb->protocol = htons(ETH_P_X25);
 207
 208         ptr = skb_push(skb, 2);
 209
 210         *ptr++ = size % 256;
 211         *ptr++ = size / 256;
 212
 213         lapbeth->stats.tx_packets++;
 214         lapbeth->stats.tx_bytes += size;
 215
 216         skb->dev = dev = lapbeth->ethdev;
 217
 218         dev->hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
 219
 220         dev_queue_xmit(skb);
 221 }
 222
 223 static void lapbeth_connected(struct net_device *dev, int reason)
 224 {
 225         unsigned char *ptr;
 226         struct sk_buff *skb = dev_alloc_skb(1);
 227
 228         if (!skb) {
 229                 printk(KERN_ERR "lapbeth: out of memory\n");
 230                 return;
 231         }
 232
 233         ptr  = skb_put(skb, 1);
 234         *ptr = 0x01;
 235
 236         skb->dev      = dev;
 237         skb->protocol = htons(ETH_P_X25);
 238         skb->mac.raw  = skb->data;
 239         skb->pkt_type = PACKET_HOST;
 240
 241         skb->dev->last_rx = jiffies;
 242         netif_rx(skb);
 243 }
 244
 245 static void lapbeth_disconnected(struct net_device *dev, int reason)
 246 {
 247         unsigned char *ptr;
 248         struct sk_buff *skb = dev_alloc_skb(1);
 249
 250         if (!skb) {
 251                 printk(KERN_ERR "lapbeth: out of memory\n");
 252                 return;
 253         }
 254
 255         ptr  = skb_put(skb, 1);
 256         *ptr = 0x02;
 257
 258         skb->dev      = dev;
 259         skb->protocol = htons(ETH_P_X25);
 260         skb->mac.raw  = skb->data;
 261         skb->pkt_type = PACKET_HOST;
 262
 263         skb->dev->last_rx = jiffies;
 264         netif_rx(skb);
 265 }
 266
 267 /*
 268  *      Statistics
 269  */
 270 static struct net_device_stats *lapbeth_get_stats(struct net_device *dev)
 271 {
 272         struct lapbethdev *lapbeth = netdev_priv(dev);
 273         return &lapbeth->stats;
 274 }
 275
 276 /*
 277  *      Set AX.25 callsign
 278  */
 279 static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
 280 {
 281         struct sockaddr *sa = addr;
 282         memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 283         return 0;
 284 }
 285
 286
 287 static struct lapb_register_struct lapbeth_callbacks = {
 288         .connect_confirmation    = lapbeth_connected,
 289         .connect_indication      = lapbeth_connected,
 290         .disconnect_confirmation = lapbeth_disconnected,
 291         .disconnect_indication   = lapbeth_disconnected,
 292         .data_indication         = lapbeth_data_indication,
 293         .data_transmit           = lapbeth_data_transmit,
 294
 295 };
 296
 297 /*
 298  * open/close a device
 299  */
 300 static int lapbeth_open(struct net_device *dev)
 301 {
 302         int err;
 303
 304         if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
 305                 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
 306                 return -ENODEV;
 307         }
 308
 309         netif_start_queue(dev);
 310         return 0;
 311 }
 312
 313 static int lapbeth_close(struct net_device *dev)
 314 {
 315         int err;
 316
 317         netif_stop_queue(dev);
 318
 319         if ((err = lapb_unregister(dev)) != LAPB_OK)
 320                 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
 321
 322         return 0;
 323 }
 324
 325 /* ------------------------------------------------------------------------ */
 326
 327 static void lapbeth_setup(struct net_device *dev)
 328 {
 329         dev->hard_start_xmit = lapbeth_xmit;
 330         dev->open            = lapbeth_open;
 331         dev->stop            = lapbeth_close;
 332         dev->destructor      = free_netdev;
 333         dev->set_mac_address = lapbeth_set_mac_address;
 334         dev->get_stats       = lapbeth_get_stats;
 335         dev->type            = ARPHRD_X25;
 336         dev->hard_header_len = 3;
 337         dev->mtu             = 1000;
 338         dev->addr_len        = 0;
 339         SET_MODULE_OWNER(dev);
 340 }
 341
 342 /*
 343  *      Setup a new device.
 344  */
 345 static int lapbeth_new_device(struct net_device *dev)
 346 {
 347         struct net_device *ndev;
 348         struct lapbethdev *lapbeth;
 349         int rc = -ENOMEM;
 350
 351         ASSERT_RTNL();
 352
 353         ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
 354                            lapbeth_setup);
 355         if (!ndev)
 356                 goto out;
 357
 358         lapbeth = netdev_priv(ndev);
 359         lapbeth->axdev = ndev;
 360
 361         dev_hold(dev);
 362         lapbeth->ethdev = dev;
 363
 364         rc = dev_alloc_name(ndev, ndev->name);
 365         if (rc < 0)
 366                 goto fail;
 367
 368         rc = -EIO;
 369         if (register_netdevice(ndev))
 370                 goto fail;
 371
 372         list_add_rcu(&lapbeth->node, &lapbeth_devices);
 373         rc = 0;
 374 out:
 375         return rc;
 376 fail:
 377         dev_put(dev);
 378         free_netdev(ndev);
 379         kfree(lapbeth);
 380         goto out;
 381 }
 382
 383 /*
 384  *      Free a lapb network device.
 385  */
 386 static void lapbeth_free_device(struct lapbethdev *lapbeth)
 387 {
 388         dev_put(lapbeth->ethdev);
 389         list_del_rcu(&lapbeth->node);
 390         unregister_netdevice(lapbeth->axdev);
 391 }
 392
 393 /*
 394  *      Handle device status changes.
 395  *
 396  * Called from notifier with RTNL held.
 397  */
 398 static int lapbeth_device_event(struct notifier_block *this,
 399                                 unsigned long event, void *ptr)
 400 {
 401         struct lapbethdev *lapbeth;
 402         struct net_device *dev = ptr;
 403
 404         if (!dev_is_ethdev(dev))
 405                 return NOTIFY_DONE;
 406
 407         switch (event) {
 408         case NETDEV_UP:
 409                 /* New ethernet device -> new LAPB interface     */
 410                 if (lapbeth_get_x25_dev(dev) == NULL)
 411                         lapbeth_new_device(dev);
 412                 break;
 413         case NETDEV_DOWN:
 414                 /* ethernet device closed -> close LAPB interface */
 415                 lapbeth = lapbeth_get_x25_dev(dev);
 416                 if (lapbeth)
 417                         dev_close(lapbeth->axdev);
 418                 break;
 419         case NETDEV_UNREGISTER:
 420                 /* ethernet device disappears -> remove LAPB interface */
 421                 lapbeth = lapbeth_get_x25_dev(dev);
 422                 if (lapbeth)
 423                         lapbeth_free_device(lapbeth);
 424                 break;
 425         }
 426
 427         return NOTIFY_DONE;
 428 }
 429
 430 /* ------------------------------------------------------------------------ */
 431
 432 static struct packet_type lapbeth_packet_type = {
 433         .type = __constant_htons(ETH_P_DEC),
 434         .func = lapbeth_rcv,
 435 };
 436
 437 static struct notifier_block lapbeth_dev_notifier = {
 438         .notifier_call = lapbeth_device_event,
 439 };
 440
 441 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n";
 442
 443 static int __init lapbeth_init_driver(void)
 444 {
 445         dev_add_pack(&lapbeth_packet_type);
 446
 447         register_netdevice_notifier(&lapbeth_dev_notifier);
 448
 449         printk(banner);
 450
 451         return 0;
 452 }
 453 module_init(lapbeth_init_driver);
 454
 455 static void __exit lapbeth_cleanup_driver(void)
 456 {
 457         struct lapbethdev *lapbeth;
 458         struct list_head *entry, *tmp;
 459
 460         dev_remove_pack(&lapbeth_packet_type);
 461         unregister_netdevice_notifier(&lapbeth_dev_notifier);
 462
 463         rtnl_lock();
 464         list_for_each_safe(entry, tmp, &lapbeth_devices) {
 465                 lapbeth = list_entry(entry, struct lapbethdev, node);
 466
 467                 unregister_netdevice(lapbeth->axdev);
 468         }
 469         rtnl_unlock();
 470 }
 471 module_exit(lapbeth_cleanup_driver);
 472
 473 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
 474 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
 475 MODULE_LICENSE("GPL");