drivers/net/hamradio/bpqether.c

   1 /*
   2  *      G8BPQ compatible "AX.25 via ethernet" driver release 004
   3  *
   4  *      This code REQUIRES 2.0.0 or higher/ NET3.029
   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 AX.25 over Ethernet
  13  *      using G8BPQ encapsulation. It has been extracted from the protocol
  14  *      implementation because
  15  *
  16  *              - things got unreadable within the protocol stack
  17  *              - to cure the protocol stack from "feature-ism"
  18  *              - a protocol implementation shouldn't need to know on
  19  *                which hardware it is running
  20  *              - user-level programs like the AX.25 utilities shouldn't
  21  *                need to know about the hardware.
  22  *              - IP over ethernet encapsulated AX.25 was impossible
  23  *              - rxecho.c did not work
  24  *              - to have room for extensions
  25  *              - it just deserves to "live" as an own driver
  26  *
  27  *      This driver can use any ethernet destination address, and can be
  28  *      limited to accept frames from one dedicated ethernet card only.
  29  *
  30  *      Note that the driver sets up the BPQ devices automagically on
  31  *      startup or (if started before the "insmod" of an ethernet device)
  32  *      on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
  33  *      the ethernet device (in fact: as soon as another ethernet or bpq
  34  *      device gets "ifconfig"ured).
  35  *
  36  *      I have heard that several people are thinking of experiments
  37  *      with highspeed packet radio using existing ethernet cards.
  38  *      Well, this driver is prepared for this purpose, just add
  39  *      your tx key control and a txdelay / tailtime algorithm,
  40  *      probably some buffering, and /voila/...
  41  *
  42  *      History
  43  *      BPQ   001       Joerg(DL1BKE)           Extracted BPQ code from AX.25
  44  *                                              protocol stack and added my own
  45  *                                              yet existing patches
  46  *      BPQ   002       Joerg(DL1BKE)           Scan network device list on
  47  *                                              startup.
  48  *      BPQ   003       Joerg(DL1BKE)           Ethernet destination address
  49  *                                              and accepted source address
  50  *                                              can be configured by an ioctl()
  51  *                                              call.
  52  *                                              Fixed to match Linux networking
  53  *                                              changes - 2.1.15.
  54  *      BPQ   004       Joerg(DL1BKE)           Fixed to not lock up on ifconfig.
  55  */
  56
  57 #include <linux/errno.h>
  58 #include <linux/types.h>
  59 #include <linux/socket.h>
  60 #include <linux/in.h>
  61 #include <linux/kernel.h>
  62 #include <linux/string.h>
  63 #include <linux/net.h>
  64 #include <net/ax25.h>
  65 #include <linux/inet.h>
  66 #include <linux/netdevice.h>
  67 #include <linux/etherdevice.h>
  68 #include <linux/if_arp.h>
  69 #include <linux/skbuff.h>
  70 #include <net/sock.h>
  71 #include <asm/system.h>
  72 #include <asm/uaccess.h>
  73 #include <linux/mm.h>
  74 #include <linux/interrupt.h>
  75 #include <linux/notifier.h>
  76 #include <linux/proc_fs.h>
  77 #include <linux/seq_file.h>
  78 #include <linux/stat.h>
  79 #include <linux/netfilter.h>
  80 #include <linux/module.h>
  81 #include <linux/init.h>
  82 #include <linux/rtnetlink.h>
  83
  84 #include <net/ip.h>
  85 #include <net/arp.h>
  86 #include <net/net_namespace.h>
  87
  88 #include <linux/bpqether.h>
  89
  90 static char banner[] __initdata = KERN_INFO "AX.25: bpqether driver version 004\n";
  91
  92 static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
  93
  94 static char bpq_eth_addr[6];
  95
  96 static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
  97 static int bpq_device_event(struct notifier_block *, unsigned long, void *);
  98
  99 static struct packet_type bpq_packet_type = {
 100         .type   = __constant_htons(ETH_P_BPQ),
 101         .func   = bpq_rcv,
 102 };
 103
 104 static struct notifier_block bpq_dev_notifier = {
 105         .notifier_call =bpq_device_event,
 106 };
 107
 108
 109 struct bpqdev {
 110         struct list_head bpq_list;      /* list of bpq devices chain */
 111         struct net_device *ethdev;      /* link to ethernet device */
 112         struct net_device *axdev;       /* bpq device (bpq#) */
 113         struct net_device_stats stats;  /* some statistics */
 114         char   dest_addr[6];            /* ether destination address */
 115         char   acpt_addr[6];            /* accept ether frames from this address only */
 116 };
 117
 118 static LIST_HEAD(bpq_devices);
 119
 120 /*
 121  * bpqether network devices are paired with ethernet devices below them, so
 122  * form a special "super class" of normal ethernet devices; split their locks
 123  * off into a separate class since they always nest.
 124  */
 125 static struct lock_class_key bpq_netdev_xmit_lock_key;
 126
 127 static void bpq_set_lockdep_class_one(struct netdev_queue *txq)
 128 {
 129         lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
 130 }
 131
 132 static void bpq_set_lockdep_class(struct net_device *dev)
 133 {
 134         bpq_set_lockdep_class_one(&dev->tx_queue);
 135 }
 136
 137 /* ------------------------------------------------------------------------ */
 138
 139
 140 /*
 141  *      Get the ethernet device for a BPQ device
 142  */
 143 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
 144 {
 145         struct bpqdev *bpq = netdev_priv(dev);
 146
 147         return bpq ? bpq->ethdev : NULL;
 148 }
 149
 150 /*
 151  *      Get the BPQ device for the ethernet device
 152  */
 153 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
 154 {
 155         struct bpqdev *bpq;
 156
 157         list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
 158                 if (bpq->ethdev == dev)
 159                         return bpq->axdev;
 160         }
 161         return NULL;
 162 }
 163
 164 static inline int dev_is_ethdev(struct net_device *dev)
 165 {
 166         return (
 167                         dev->type == ARPHRD_ETHER
 168                         && strncmp(dev->name, "dummy", 5)
 169         );
 170 }
 171
 172 /* ------------------------------------------------------------------------ */
 173
 174
 175 /*
 176  *      Receive an AX.25 frame via an ethernet interface.
 177  */
 178 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
 179 {
 180         int len;
 181         char * ptr;
 182         struct ethhdr *eth;
 183         struct bpqdev *bpq;
 184
 185         if (dev_net(dev) != &init_net)
 186                 goto drop;
 187
 188         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 189                 return NET_RX_DROP;
 190
 191         if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
 192                 goto drop;
 193
 194         rcu_read_lock();
 195         dev = bpq_get_ax25_dev(dev);
 196
 197         if (dev == NULL || !netif_running(dev))
 198                 goto drop_unlock;
 199
 200         /*
 201          * if we want to accept frames from just one ethernet device
 202          * we check the source address of the sender.
 203          */
 204
 205         bpq = netdev_priv(dev);
 206
 207         eth = eth_hdr(skb);
 208
 209         if (!(bpq->acpt_addr[0] & 0x01) &&
 210             memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
 211                 goto drop_unlock;
 212
 213         if (skb_cow(skb, sizeof(struct ethhdr)))
 214                 goto drop_unlock;
 215
 216         len = skb->data[0] + skb->data[1] * 256 - 5;
 217
 218         skb_pull(skb, 2);       /* Remove the length bytes */
 219         skb_trim(skb, len);     /* Set the length of the data */
 220
 221         bpq->stats.rx_packets++;
 222         bpq->stats.rx_bytes += len;
 223
 224         ptr = skb_push(skb, 1);
 225         *ptr = 0;
 226
 227         skb->protocol = ax25_type_trans(skb, dev);
 228         netif_rx(skb);
 229         dev->last_rx = jiffies;
 230 unlock:
 231
 232         rcu_read_unlock();
 233
 234         return 0;
 235 drop_unlock:
 236         kfree_skb(skb);
 237         goto unlock;
 238
 239 drop:
 240         kfree_skb(skb);
 241         return 0;
 242 }
 243
 244 /*
 245  *      Send an AX.25 frame via an ethernet interface
 246  */
 247 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
 248 {
 249         struct sk_buff *newskb;
 250         unsigned char *ptr;
 251         struct bpqdev *bpq;
 252         int size;
 253
 254         /*
 255          * Just to be *really* sure not to send anything if the interface
 256          * is down, the ethernet device may have gone.
 257          */
 258         if (!netif_running(dev)) {
 259                 kfree_skb(skb);
 260                 return -ENODEV;
 261         }
 262
 263         skb_pull(skb, 1);
 264         size = skb->len;
 265
 266         /*
 267          * The AX.25 code leaves enough room for the ethernet header, but
 268          * sendto() does not.
 269          */
 270         if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {  /* Ough! */
 271                 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
 272                         printk(KERN_WARNING "bpqether: out of memory\n");
 273                         kfree_skb(skb);
 274                         return -ENOMEM;
 275                 }
 276
 277                 if (skb->sk != NULL)
 278                         skb_set_owner_w(newskb, skb->sk);
 279
 280                 kfree_skb(skb);
 281                 skb = newskb;
 282         }
 283
 284         ptr = skb_push(skb, 2);
 285
 286         *ptr++ = (size + 5) % 256;
 287         *ptr++ = (size + 5) / 256;
 288
 289         bpq = netdev_priv(dev);
 290
 291         if ((dev = bpq_get_ether_dev(dev)) == NULL) {
 292                 bpq->stats.tx_dropped++;
 293                 kfree_skb(skb);
 294                 return -ENODEV;
 295         }
 296
 297         skb->protocol = ax25_type_trans(skb, dev);
 298         skb_reset_network_header(skb);
 299         dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 300         bpq->stats.tx_packets++;
 301         bpq->stats.tx_bytes+=skb->len;
 302
 303         dev_queue_xmit(skb);
 304         netif_wake_queue(dev);
 305         return 0;
 306 }
 307
 308 /*
 309  *      Statistics
 310  */
 311 static struct net_device_stats *bpq_get_stats(struct net_device *dev)
 312 {
 313         struct bpqdev *bpq = netdev_priv(dev);
 314
 315         return &bpq->stats;
 316 }
 317
 318 /*
 319  *      Set AX.25 callsign
 320  */
 321 static int bpq_set_mac_address(struct net_device *dev, void *addr)
 322 {
 323     struct sockaddr *sa = (struct sockaddr *)addr;
 324
 325     memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 326
 327     return 0;
 328 }
 329
 330 /*      Ioctl commands
 331  *
 332  *              SIOCSBPQETHOPT          reserved for enhancements
 333  *              SIOCSBPQETHADDR         set the destination and accepted
 334  *                                      source ethernet address (broadcast
 335  *                                      or multicast: accept all)
 336  */
 337 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 338 {
 339         struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
 340         struct bpqdev *bpq = netdev_priv(dev);
 341         struct bpq_req req;
 342
 343         if (!capable(CAP_NET_ADMIN))
 344                 return -EPERM;
 345
 346         switch (cmd) {
 347                 case SIOCSBPQETHOPT:
 348                         if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
 349                                 return -EFAULT;
 350                         switch (req.cmd) {
 351                                 case SIOCGBPQETHPARAM:
 352                                 case SIOCSBPQETHPARAM:
 353                                 default:
 354                                         return -EINVAL;
 355                         }
 356
 357                         break;
 358
 359                 case SIOCSBPQETHADDR:
 360                         if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
 361                                 return -EFAULT;
 362                         if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
 363                                 return -EFAULT;
 364                         break;
 365
 366                 default:
 367                         return -EINVAL;
 368         }
 369
 370         return 0;
 371 }
 372
 373 /*
 374  * open/close a device
 375  */
 376 static int bpq_open(struct net_device *dev)
 377 {
 378         netif_start_queue(dev);
 379         return 0;
 380 }
 381
 382 static int bpq_close(struct net_device *dev)
 383 {
 384         netif_stop_queue(dev);
 385         return 0;
 386 }
 387
 388
 389 /* ------------------------------------------------------------------------ */
 390
 391
 392 /*
 393  *      Proc filesystem
 394  */
 395 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
 396 {
 397         int i = 1;
 398         struct bpqdev *bpqdev;
 399
 400         rcu_read_lock();
 401
 402         if (*pos == 0)
 403                 return SEQ_START_TOKEN;
 404
 405         list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
 406                 if (i == *pos)
 407                         return bpqdev;
 408         }
 409         return NULL;
 410 }
 411
 412 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 413 {
 414         struct list_head *p;
 415
 416         ++*pos;
 417
 418         if (v == SEQ_START_TOKEN)
 419                 p = rcu_dereference(bpq_devices.next);
 420         else
 421                 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);
 422
 423         return (p == &bpq_devices) ? NULL
 424                 : list_entry(p, struct bpqdev, bpq_list);
 425 }
 426
 427 static void bpq_seq_stop(struct seq_file *seq, void *v)
 428 {
 429         rcu_read_unlock();
 430 }
 431
 432
 433 static int bpq_seq_show(struct seq_file *seq, void *v)
 434 {
 435         if (v == SEQ_START_TOKEN)
 436                 seq_puts(seq,
 437                          "dev   ether      destination        accept from\n");
 438         else {
 439                 const struct bpqdev *bpqdev = v;
 440                 DECLARE_MAC_BUF(mac);
 441
 442                 seq_printf(seq, "%-5s %-10s %s  ",
 443                         bpqdev->axdev->name, bpqdev->ethdev->name,
 444                         print_mac(mac, bpqdev->dest_addr));
 445
 446                 if (is_multicast_ether_addr(bpqdev->acpt_addr))
 447                         seq_printf(seq, "*\n");
 448                 else
 449                         seq_printf(seq, "%s\n", print_mac(mac, bpqdev->acpt_addr));
 450
 451         }
 452         return 0;
 453 }
 454
 455 static struct seq_operations bpq_seqops = {
 456         .start = bpq_seq_start,
 457         .next = bpq_seq_next,
 458         .stop = bpq_seq_stop,
 459         .show = bpq_seq_show,
 460 };
 461
 462 static int bpq_info_open(struct inode *inode, struct file *file)
 463 {
 464         return seq_open(file, &bpq_seqops);
 465 }
 466
 467 static const struct file_operations bpq_info_fops = {
 468         .owner = THIS_MODULE,
 469         .open = bpq_info_open,
 470         .read = seq_read,
 471         .llseek = seq_lseek,
 472         .release = seq_release,
 473 };
 474
 475
 476 /* ------------------------------------------------------------------------ */
 477
 478
 479 static void bpq_setup(struct net_device *dev)
 480 {
 481
 482         dev->hard_start_xmit = bpq_xmit;
 483         dev->open            = bpq_open;
 484         dev->stop            = bpq_close;
 485         dev->set_mac_address = bpq_set_mac_address;
 486         dev->get_stats       = bpq_get_stats;
 487         dev->do_ioctl        = bpq_ioctl;
 488         dev->destructor      = free_netdev;
 489
 490         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 491         memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);
 492
 493         dev->flags      = 0;
 494
 495 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
 496         dev->header_ops      = &ax25_header_ops;
 497 #endif
 498
 499         dev->type            = ARPHRD_AX25;
 500         dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
 501         dev->mtu             = AX25_DEF_PACLEN;
 502         dev->addr_len        = AX25_ADDR_LEN;
 503
 504 }
 505
 506 /*
 507  *      Setup a new device.
 508  */
 509 static int bpq_new_device(struct net_device *edev)
 510 {
 511         int err;
 512         struct net_device *ndev;
 513         struct bpqdev *bpq;
 514
 515         ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
 516                            bpq_setup);
 517         if (!ndev)
 518                 return -ENOMEM;
 519
 520
 521         bpq = netdev_priv(ndev);
 522         dev_hold(edev);
 523         bpq->ethdev = edev;
 524         bpq->axdev = ndev;
 525
 526         memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
 527         memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
 528
 529         err = dev_alloc_name(ndev, ndev->name);
 530         if (err < 0)
 531                 goto error;
 532
 533         err = register_netdevice(ndev);
 534         if (err)
 535                 goto error;
 536         bpq_set_lockdep_class(ndev);
 537
 538         /* List protected by RTNL */
 539         list_add_rcu(&bpq->bpq_list, &bpq_devices);
 540         return 0;
 541
 542  error:
 543         dev_put(edev);
 544         free_netdev(ndev);
 545         return err;
 546
 547 }
 548
 549 static void bpq_free_device(struct net_device *ndev)
 550 {
 551         struct bpqdev *bpq = netdev_priv(ndev);
 552
 553         dev_put(bpq->ethdev);
 554         list_del_rcu(&bpq->bpq_list);
 555
 556         unregister_netdevice(ndev);
 557 }
 558
 559 /*
 560  *      Handle device status changes.
 561  */
 562 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 563 {
 564         struct net_device *dev = (struct net_device *)ptr;
 565
 566         if (dev_net(dev) != &init_net)
 567                 return NOTIFY_DONE;
 568
 569         if (!dev_is_ethdev(dev))
 570                 return NOTIFY_DONE;
 571
 572         switch (event) {
 573         case NETDEV_UP:         /* new ethernet device -> new BPQ interface */
 574                 if (bpq_get_ax25_dev(dev) == NULL)
 575                         bpq_new_device(dev);
 576                 break;
 577
 578         case NETDEV_DOWN:       /* ethernet device closed -> close BPQ interface */
 579                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 580                         dev_close(dev);
 581                 break;
 582
 583         case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
 584                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 585                         bpq_free_device(dev);
 586                 break;
 587         default:
 588                 break;
 589         }
 590
 591         return NOTIFY_DONE;
 592 }
 593
 594
 595 /* ------------------------------------------------------------------------ */
 596
 597 /*
 598  * Initialize driver. To be called from af_ax25 if not compiled as a
 599  * module
 600  */
 601 static int __init bpq_init_driver(void)
 602 {
 603 #ifdef CONFIG_PROC_FS
 604         if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
 605                 printk(KERN_ERR
 606                         "bpq: cannot create /proc/net/bpqether entry.\n");
 607                 return -ENOENT;
 608         }
 609 #endif  /* CONFIG_PROC_FS */
 610
 611         dev_add_pack(&bpq_packet_type);
 612
 613         register_netdevice_notifier(&bpq_dev_notifier);
 614
 615         printk(banner);
 616
 617         return 0;
 618 }
 619
 620 static void __exit bpq_cleanup_driver(void)
 621 {
 622         struct bpqdev *bpq;
 623
 624         dev_remove_pack(&bpq_packet_type);
 625
 626         unregister_netdevice_notifier(&bpq_dev_notifier);
 627
 628         proc_net_remove(&init_net, "bpqether");
 629
 630         rtnl_lock();
 631         while (!list_empty(&bpq_devices)) {
 632                 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
 633                 bpq_free_device(bpq->axdev);
 634         }
 635         rtnl_unlock();
 636 }
 637
 638 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
 639 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
 640 MODULE_LICENSE("GPL");
 641 module_init(bpq_init_driver);
 642 module_exit(bpq_cleanup_driver);