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 <linux/slab.h>
  65 #include <net/ax25.h>
  66 #include <linux/inet.h>
  67 #include <linux/netdevice.h>
  68 #include <linux/etherdevice.h>
  69 #include <linux/if_arp.h>
  70 #include <linux/skbuff.h>
  71 #include <net/sock.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 const char banner[] __initdata = KERN_INFO \
  91         "AX.25: bpqether driver version 004\n";
  92
  93 static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
  94
  95 static char bpq_eth_addr[6];
  96
  97 static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
  98 static int bpq_device_event(struct notifier_block *, unsigned long, void *);
  99
 100 static struct packet_type bpq_packet_type __read_mostly = {
 101         .type   = cpu_to_be16(ETH_P_BPQ),
 102         .func   = bpq_rcv,
 103 };
 104
 105 static struct notifier_block bpq_dev_notifier = {
 106         .notifier_call =bpq_device_event,
 107 };
 108
 109
 110 struct bpqdev {
 111         struct list_head bpq_list;      /* list of bpq devices chain */
 112         struct net_device *ethdev;      /* link to ethernet device */
 113         struct net_device *axdev;       /* bpq device (bpq#) */
 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 static struct lock_class_key bpq_netdev_addr_lock_key;
 127
 128 static void bpq_set_lockdep_class_one(struct net_device *dev,
 129                                       struct netdev_queue *txq,
 130                                       void *_unused)
 131 {
 132         lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
 133 }
 134
 135 static void bpq_set_lockdep_class(struct net_device *dev)
 136 {
 137         lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
 138         netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
 139 }
 140
 141 /* ------------------------------------------------------------------------ */
 142
 143
 144 /*
 145  *      Get the ethernet device for a BPQ device
 146  */
 147 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
 148 {
 149         struct bpqdev *bpq = netdev_priv(dev);
 150
 151         return bpq ? bpq->ethdev : NULL;
 152 }
 153
 154 /*
 155  *      Get the BPQ device for the ethernet device
 156  */
 157 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
 158 {
 159         struct bpqdev *bpq;
 160
 161         list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
 162                 if (bpq->ethdev == dev)
 163                         return bpq->axdev;
 164         }
 165         return NULL;
 166 }
 167
 168 static inline int dev_is_ethdev(struct net_device *dev)
 169 {
 170         return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
 171 }
 172
 173 /* ------------------------------------------------------------------------ */
 174
 175
 176 /*
 177  *      Receive an AX.25 frame via an ethernet interface.
 178  */
 179 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
 180 {
 181         int len;
 182         char * ptr;
 183         struct ethhdr *eth;
 184         struct bpqdev *bpq;
 185
 186         if (!net_eq(dev_net(dev), &init_net))
 187                 goto drop;
 188
 189         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 190                 return NET_RX_DROP;
 191
 192         if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
 193                 goto drop;
 194
 195         rcu_read_lock();
 196         dev = bpq_get_ax25_dev(dev);
 197
 198         if (dev == NULL || !netif_running(dev))
 199                 goto drop_unlock;
 200
 201         /*
 202          * if we want to accept frames from just one ethernet device
 203          * we check the source address of the sender.
 204          */
 205
 206         bpq = netdev_priv(dev);
 207
 208         eth = eth_hdr(skb);
 209
 210         if (!(bpq->acpt_addr[0] & 0x01) &&
 211             memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
 212                 goto drop_unlock;
 213
 214         if (skb_cow(skb, sizeof(struct ethhdr)))
 215                 goto drop_unlock;
 216
 217         len = skb->data[0] + skb->data[1] * 256 - 5;
 218
 219         skb_pull(skb, 2);       /* Remove the length bytes */
 220         skb_trim(skb, len);     /* Set the length of the data */
 221
 222         dev->stats.rx_packets++;
 223         dev->stats.rx_bytes += len;
 224
 225         ptr = skb_push(skb, 1);
 226         *ptr = 0;
 227
 228         skb->protocol = ax25_type_trans(skb, dev);
 229         netif_rx(skb);
 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 netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
 248 {
 249         unsigned char *ptr;
 250         struct bpqdev *bpq;
 251         struct net_device *orig_dev;
 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 NETDEV_TX_OK;
 261         }
 262
 263         skb_pull(skb, 1);                       /* Drop KISS byte */
 264         size = skb->len;
 265
 266         /*
 267          * We're about to mess with the skb which may still shared with the
 268          * generic networking code so unshare and ensure it's got enough
 269          * space for the BPQ headers.
 270          */
 271         if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
 272                 if (net_ratelimit())
 273                         pr_err("bpqether: out of memory\n");
 274                 kfree_skb(skb);
 275
 276                 return NETDEV_TX_OK;
 277         }
 278
 279         ptr = skb_push(skb, 2);                 /* Make space for length */
 280
 281         *ptr++ = (size + 5) % 256;
 282         *ptr++ = (size + 5) / 256;
 283
 284         bpq = netdev_priv(dev);
 285
 286         orig_dev = dev;
 287         if ((dev = bpq_get_ether_dev(dev)) == NULL) {
 288                 orig_dev->stats.tx_dropped++;
 289                 kfree_skb(skb);
 290                 return NETDEV_TX_OK;
 291         }
 292
 293         skb->protocol = ax25_type_trans(skb, dev);
 294         skb_reset_network_header(skb);
 295         dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 296         dev->stats.tx_packets++;
 297         dev->stats.tx_bytes+=skb->len;
 298
 299         dev_queue_xmit(skb);
 300         netif_wake_queue(dev);
 301         return NETDEV_TX_OK;
 302 }
 303
 304 /*
 305  *      Set AX.25 callsign
 306  */
 307 static int bpq_set_mac_address(struct net_device *dev, void *addr)
 308 {
 309     struct sockaddr *sa = (struct sockaddr *)addr;
 310
 311     memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 312
 313     return 0;
 314 }
 315
 316 /*      Ioctl commands
 317  *
 318  *              SIOCSBPQETHOPT          reserved for enhancements
 319  *              SIOCSBPQETHADDR         set the destination and accepted
 320  *                                      source ethernet address (broadcast
 321  *                                      or multicast: accept all)
 322  */
 323 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 324 {
 325         struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
 326         struct bpqdev *bpq = netdev_priv(dev);
 327         struct bpq_req req;
 328
 329         if (!capable(CAP_NET_ADMIN))
 330                 return -EPERM;
 331
 332         switch (cmd) {
 333                 case SIOCSBPQETHOPT:
 334                         if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
 335                                 return -EFAULT;
 336                         switch (req.cmd) {
 337                                 case SIOCGBPQETHPARAM:
 338                                 case SIOCSBPQETHPARAM:
 339                                 default:
 340                                         return -EINVAL;
 341                         }
 342
 343                         break;
 344
 345                 case SIOCSBPQETHADDR:
 346                         if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
 347                                 return -EFAULT;
 348                         if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
 349                                 return -EFAULT;
 350                         break;
 351
 352                 default:
 353                         return -EINVAL;
 354         }
 355
 356         return 0;
 357 }
 358
 359 /*
 360  * open/close a device
 361  */
 362 static int bpq_open(struct net_device *dev)
 363 {
 364         netif_start_queue(dev);
 365         return 0;
 366 }
 367
 368 static int bpq_close(struct net_device *dev)
 369 {
 370         netif_stop_queue(dev);
 371         return 0;
 372 }
 373
 374
 375 /* ------------------------------------------------------------------------ */
 376
 377
 378 /*
 379  *      Proc filesystem
 380  */
 381 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
 382         __acquires(RCU)
 383 {
 384         int i = 1;
 385         struct bpqdev *bpqdev;
 386
 387         rcu_read_lock();
 388
 389         if (*pos == 0)
 390                 return SEQ_START_TOKEN;
 391
 392         list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
 393                 if (i == *pos)
 394                         return bpqdev;
 395         }
 396         return NULL;
 397 }
 398
 399 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 400 {
 401         struct list_head *p;
 402         struct bpqdev *bpqdev = v;
 403
 404         ++*pos;
 405
 406         if (v == SEQ_START_TOKEN)
 407                 p = rcu_dereference(list_next_rcu(&bpq_devices));
 408         else
 409                 p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list));
 410
 411         return (p == &bpq_devices) ? NULL
 412                 : list_entry(p, struct bpqdev, bpq_list);
 413 }
 414
 415 static void bpq_seq_stop(struct seq_file *seq, void *v)
 416         __releases(RCU)
 417 {
 418         rcu_read_unlock();
 419 }
 420
 421
 422 static int bpq_seq_show(struct seq_file *seq, void *v)
 423 {
 424         if (v == SEQ_START_TOKEN)
 425                 seq_puts(seq,
 426                          "dev   ether      destination        accept from\n");
 427         else {
 428                 const struct bpqdev *bpqdev = v;
 429
 430                 seq_printf(seq, "%-5s %-10s %pM  ",
 431                         bpqdev->axdev->name, bpqdev->ethdev->name,
 432                         bpqdev->dest_addr);
 433
 434                 if (is_multicast_ether_addr(bpqdev->acpt_addr))
 435                         seq_printf(seq, "*\n");
 436                 else
 437                         seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
 438
 439         }
 440         return 0;
 441 }
 442
 443 static const struct seq_operations bpq_seqops = {
 444         .start = bpq_seq_start,
 445         .next = bpq_seq_next,
 446         .stop = bpq_seq_stop,
 447         .show = bpq_seq_show,
 448 };
 449
 450 static int bpq_info_open(struct inode *inode, struct file *file)
 451 {
 452         return seq_open(file, &bpq_seqops);
 453 }
 454
 455 static const struct file_operations bpq_info_fops = {
 456         .owner = THIS_MODULE,
 457         .open = bpq_info_open,
 458         .read = seq_read,
 459         .llseek = seq_lseek,
 460         .release = seq_release,
 461 };
 462
 463
 464 /* ------------------------------------------------------------------------ */
 465
 466 static const struct net_device_ops bpq_netdev_ops = {
 467         .ndo_open            = bpq_open,
 468         .ndo_stop            = bpq_close,
 469         .ndo_start_xmit      = bpq_xmit,
 470         .ndo_set_mac_address = bpq_set_mac_address,
 471         .ndo_do_ioctl        = bpq_ioctl,
 472 };
 473
 474 static void bpq_setup(struct net_device *dev)
 475 {
 476         dev->netdev_ops      = &bpq_netdev_ops;
 477         dev->destructor      = free_netdev;
 478
 479         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 480         memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);
 481
 482         dev->flags      = 0;
 483
 484 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
 485         dev->header_ops      = &ax25_header_ops;
 486 #endif
 487
 488         dev->type            = ARPHRD_AX25;
 489         dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
 490         dev->mtu             = AX25_DEF_PACLEN;
 491         dev->addr_len        = AX25_ADDR_LEN;
 492
 493 }
 494
 495 /*
 496  *      Setup a new device.
 497  */
 498 static int bpq_new_device(struct net_device *edev)
 499 {
 500         int err;
 501         struct net_device *ndev;
 502         struct bpqdev *bpq;
 503
 504         ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
 505                            bpq_setup);
 506         if (!ndev)
 507                 return -ENOMEM;
 508
 509
 510         bpq = netdev_priv(ndev);
 511         dev_hold(edev);
 512         bpq->ethdev = edev;
 513         bpq->axdev = ndev;
 514
 515         memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
 516         memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
 517
 518         err = register_netdevice(ndev);
 519         if (err)
 520                 goto error;
 521         bpq_set_lockdep_class(ndev);
 522
 523         /* List protected by RTNL */
 524         list_add_rcu(&bpq->bpq_list, &bpq_devices);
 525         return 0;
 526
 527  error:
 528         dev_put(edev);
 529         free_netdev(ndev);
 530         return err;
 531
 532 }
 533
 534 static void bpq_free_device(struct net_device *ndev)
 535 {
 536         struct bpqdev *bpq = netdev_priv(ndev);
 537
 538         dev_put(bpq->ethdev);
 539         list_del_rcu(&bpq->bpq_list);
 540
 541         unregister_netdevice(ndev);
 542 }
 543
 544 /*
 545  *      Handle device status changes.
 546  */
 547 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 548 {
 549         struct net_device *dev = (struct net_device *)ptr;
 550
 551         if (!net_eq(dev_net(dev), &init_net))
 552                 return NOTIFY_DONE;
 553
 554         if (!dev_is_ethdev(dev))
 555                 return NOTIFY_DONE;
 556
 557         switch (event) {
 558         case NETDEV_UP:         /* new ethernet device -> new BPQ interface */
 559                 if (bpq_get_ax25_dev(dev) == NULL)
 560                         bpq_new_device(dev);
 561                 break;
 562
 563         case NETDEV_DOWN:       /* ethernet device closed -> close BPQ interface */
 564                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 565                         dev_close(dev);
 566                 break;
 567
 568         case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
 569                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 570                         bpq_free_device(dev);
 571                 break;
 572         default:
 573                 break;
 574         }
 575
 576         return NOTIFY_DONE;
 577 }
 578
 579
 580 /* ------------------------------------------------------------------------ */
 581
 582 /*
 583  * Initialize driver. To be called from af_ax25 if not compiled as a
 584  * module
 585  */
 586 static int __init bpq_init_driver(void)
 587 {
 588 #ifdef CONFIG_PROC_FS
 589         if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
 590                 printk(KERN_ERR
 591                         "bpq: cannot create /proc/net/bpqether entry.\n");
 592                 return -ENOENT;
 593         }
 594 #endif  /* CONFIG_PROC_FS */
 595
 596         dev_add_pack(&bpq_packet_type);
 597
 598         register_netdevice_notifier(&bpq_dev_notifier);
 599
 600         printk(banner);
 601
 602         return 0;
 603 }
 604
 605 static void __exit bpq_cleanup_driver(void)
 606 {
 607         struct bpqdev *bpq;
 608
 609         dev_remove_pack(&bpq_packet_type);
 610
 611         unregister_netdevice_notifier(&bpq_dev_notifier);
 612
 613         proc_net_remove(&init_net, "bpqether");
 614
 615         rtnl_lock();
 616         while (!list_empty(&bpq_devices)) {
 617                 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
 618                 bpq_free_device(bpq->axdev);
 619         }
 620         rtnl_unlock();
 621 }
 622
 623 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
 624 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
 625 MODULE_LICENSE("GPL");
 626 module_init(bpq_init_driver);
 627 module_exit(bpq_cleanup_driver);