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 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 (
 171                         dev->type == ARPHRD_ETHER
 172                         && strncmp(dev->name, "dummy", 5)
 173         );
 174 }
 175
 176 /* ------------------------------------------------------------------------ */
 177
 178
 179 /*
 180  *      Receive an AX.25 frame via an ethernet interface.
 181  */
 182 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
 183 {
 184         int len;
 185         char * ptr;
 186         struct ethhdr *eth;
 187         struct bpqdev *bpq;
 188
 189         if (dev_net(dev) != &init_net)
 190                 goto drop;
 191
 192         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 193                 return NET_RX_DROP;
 194
 195         if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
 196                 goto drop;
 197
 198         rcu_read_lock();
 199         dev = bpq_get_ax25_dev(dev);
 200
 201         if (dev == NULL || !netif_running(dev))
 202                 goto drop_unlock;
 203
 204         /*
 205          * if we want to accept frames from just one ethernet device
 206          * we check the source address of the sender.
 207          */
 208
 209         bpq = netdev_priv(dev);
 210
 211         eth = eth_hdr(skb);
 212
 213         if (!(bpq->acpt_addr[0] & 0x01) &&
 214             memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
 215                 goto drop_unlock;
 216
 217         if (skb_cow(skb, sizeof(struct ethhdr)))
 218                 goto drop_unlock;
 219
 220         len = skb->data[0] + skb->data[1] * 256 - 5;
 221
 222         skb_pull(skb, 2);       /* Remove the length bytes */
 223         skb_trim(skb, len);     /* Set the length of the data */
 224
 225         dev->stats.rx_packets++;
 226         dev->stats.rx_bytes += len;
 227
 228         ptr = skb_push(skb, 1);
 229         *ptr = 0;
 230
 231         skb->protocol = ax25_type_trans(skb, dev);
 232         netif_rx(skb);
 233 unlock:
 234
 235         rcu_read_unlock();
 236
 237         return 0;
 238 drop_unlock:
 239         kfree_skb(skb);
 240         goto unlock;
 241
 242 drop:
 243         kfree_skb(skb);
 244         return 0;
 245 }
 246
 247 /*
 248  *      Send an AX.25 frame via an ethernet interface
 249  */
 250 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
 251 {
 252         struct sk_buff *newskb;
 253         unsigned char *ptr;
 254         struct bpqdev *bpq;
 255         int size;
 256
 257         /*
 258          * Just to be *really* sure not to send anything if the interface
 259          * is down, the ethernet device may have gone.
 260          */
 261         if (!netif_running(dev)) {
 262                 kfree_skb(skb);
 263                 return -ENODEV;
 264         }
 265
 266         skb_pull(skb, 1);
 267         size = skb->len;
 268
 269         /*
 270          * The AX.25 code leaves enough room for the ethernet header, but
 271          * sendto() does not.
 272          */
 273         if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {  /* Ough! */
 274                 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
 275                         printk(KERN_WARNING "bpqether: out of memory\n");
 276                         kfree_skb(skb);
 277                         return -ENOMEM;
 278                 }
 279
 280                 if (skb->sk != NULL)
 281                         skb_set_owner_w(newskb, skb->sk);
 282
 283                 kfree_skb(skb);
 284                 skb = newskb;
 285         }
 286
 287         ptr = skb_push(skb, 2);
 288
 289         *ptr++ = (size + 5) % 256;
 290         *ptr++ = (size + 5) / 256;
 291
 292         bpq = netdev_priv(dev);
 293
 294         if ((dev = bpq_get_ether_dev(dev)) == NULL) {
 295                 dev->stats.tx_dropped++;
 296                 kfree_skb(skb);
 297                 return -ENODEV;
 298         }
 299
 300         skb->protocol = ax25_type_trans(skb, dev);
 301         skb_reset_network_header(skb);
 302         dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 303         dev->stats.tx_packets++;
 304         dev->stats.tx_bytes+=skb->len;
 305
 306         dev_queue_xmit(skb);
 307         netif_wake_queue(dev);
 308         return 0;
 309 }
 310
 311 /*
 312  *      Set AX.25 callsign
 313  */
 314 static int bpq_set_mac_address(struct net_device *dev, void *addr)
 315 {
 316     struct sockaddr *sa = (struct sockaddr *)addr;
 317
 318     memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 319
 320     return 0;
 321 }
 322
 323 /*      Ioctl commands
 324  *
 325  *              SIOCSBPQETHOPT          reserved for enhancements
 326  *              SIOCSBPQETHADDR         set the destination and accepted
 327  *                                      source ethernet address (broadcast
 328  *                                      or multicast: accept all)
 329  */
 330 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 331 {
 332         struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
 333         struct bpqdev *bpq = netdev_priv(dev);
 334         struct bpq_req req;
 335
 336         if (!capable(CAP_NET_ADMIN))
 337                 return -EPERM;
 338
 339         switch (cmd) {
 340                 case SIOCSBPQETHOPT:
 341                         if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
 342                                 return -EFAULT;
 343                         switch (req.cmd) {
 344                                 case SIOCGBPQETHPARAM:
 345                                 case SIOCSBPQETHPARAM:
 346                                 default:
 347                                         return -EINVAL;
 348                         }
 349
 350                         break;
 351
 352                 case SIOCSBPQETHADDR:
 353                         if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
 354                                 return -EFAULT;
 355                         if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
 356                                 return -EFAULT;
 357                         break;
 358
 359                 default:
 360                         return -EINVAL;
 361         }
 362
 363         return 0;
 364 }
 365
 366 /*
 367  * open/close a device
 368  */
 369 static int bpq_open(struct net_device *dev)
 370 {
 371         netif_start_queue(dev);
 372         return 0;
 373 }
 374
 375 static int bpq_close(struct net_device *dev)
 376 {
 377         netif_stop_queue(dev);
 378         return 0;
 379 }
 380
 381
 382 /* ------------------------------------------------------------------------ */
 383
 384
 385 /*
 386  *      Proc filesystem
 387  */
 388 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
 389         __acquires(RCU)
 390 {
 391         int i = 1;
 392         struct bpqdev *bpqdev;
 393
 394         rcu_read_lock();
 395
 396         if (*pos == 0)
 397                 return SEQ_START_TOKEN;
 398
 399         list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
 400                 if (i == *pos)
 401                         return bpqdev;
 402         }
 403         return NULL;
 404 }
 405
 406 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 407 {
 408         struct list_head *p;
 409
 410         ++*pos;
 411
 412         if (v == SEQ_START_TOKEN)
 413                 p = rcu_dereference(bpq_devices.next);
 414         else
 415                 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);
 416
 417         return (p == &bpq_devices) ? NULL
 418                 : list_entry(p, struct bpqdev, bpq_list);
 419 }
 420
 421 static void bpq_seq_stop(struct seq_file *seq, void *v)
 422         __releases(RCU)
 423 {
 424         rcu_read_unlock();
 425 }
 426
 427
 428 static int bpq_seq_show(struct seq_file *seq, void *v)
 429 {
 430         if (v == SEQ_START_TOKEN)
 431                 seq_puts(seq,
 432                          "dev   ether      destination        accept from\n");
 433         else {
 434                 const struct bpqdev *bpqdev = v;
 435
 436                 seq_printf(seq, "%-5s %-10s %pM  ",
 437                         bpqdev->axdev->name, bpqdev->ethdev->name,
 438                         bpqdev->dest_addr);
 439
 440                 if (is_multicast_ether_addr(bpqdev->acpt_addr))
 441                         seq_printf(seq, "*\n");
 442                 else
 443                         seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
 444
 445         }
 446         return 0;
 447 }
 448
 449 static const struct seq_operations bpq_seqops = {
 450         .start = bpq_seq_start,
 451         .next = bpq_seq_next,
 452         .stop = bpq_seq_stop,
 453         .show = bpq_seq_show,
 454 };
 455
 456 static int bpq_info_open(struct inode *inode, struct file *file)
 457 {
 458         return seq_open(file, &bpq_seqops);
 459 }
 460
 461 static const struct file_operations bpq_info_fops = {
 462         .owner = THIS_MODULE,
 463         .open = bpq_info_open,
 464         .read = seq_read,
 465         .llseek = seq_lseek,
 466         .release = seq_release,
 467 };
 468
 469
 470 /* ------------------------------------------------------------------------ */
 471
 472 static const struct net_device_ops bpq_netdev_ops = {
 473         .ndo_open            = bpq_open,
 474         .ndo_stop            = bpq_close,
 475         .ndo_start_xmit      = bpq_xmit,
 476         .ndo_set_mac_address = bpq_set_mac_address,
 477         .ndo_do_ioctl        = bpq_ioctl,
 478 };
 479
 480 static void bpq_setup(struct net_device *dev)
 481 {
 482         dev->netdev_ops      = &bpq_netdev_ops;
 483         dev->destructor      = free_netdev;
 484
 485         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 486         memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);
 487
 488         dev->flags      = 0;
 489
 490 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
 491         dev->header_ops      = &ax25_header_ops;
 492 #endif
 493
 494         dev->type            = ARPHRD_AX25;
 495         dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
 496         dev->mtu             = AX25_DEF_PACLEN;
 497         dev->addr_len        = AX25_ADDR_LEN;
 498
 499 }
 500
 501 /*
 502  *      Setup a new device.
 503  */
 504 static int bpq_new_device(struct net_device *edev)
 505 {
 506         int err;
 507         struct net_device *ndev;
 508         struct bpqdev *bpq;
 509
 510         ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
 511                            bpq_setup);
 512         if (!ndev)
 513                 return -ENOMEM;
 514
 515
 516         bpq = netdev_priv(ndev);
 517         dev_hold(edev);
 518         bpq->ethdev = edev;
 519         bpq->axdev = ndev;
 520
 521         memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
 522         memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
 523
 524         err = dev_alloc_name(ndev, ndev->name);
 525         if (err < 0)
 526                 goto error;
 527
 528         err = register_netdevice(ndev);
 529         if (err)
 530                 goto error;
 531         bpq_set_lockdep_class(ndev);
 532
 533         /* List protected by RTNL */
 534         list_add_rcu(&bpq->bpq_list, &bpq_devices);
 535         return 0;
 536
 537  error:
 538         dev_put(edev);
 539         free_netdev(ndev);
 540         return err;
 541
 542 }
 543
 544 static void bpq_free_device(struct net_device *ndev)
 545 {
 546         struct bpqdev *bpq = netdev_priv(ndev);
 547
 548         dev_put(bpq->ethdev);
 549         list_del_rcu(&bpq->bpq_list);
 550
 551         unregister_netdevice(ndev);
 552 }
 553
 554 /*
 555  *      Handle device status changes.
 556  */
 557 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 558 {
 559         struct net_device *dev = (struct net_device *)ptr;
 560
 561         if (dev_net(dev) != &init_net)
 562                 return NOTIFY_DONE;
 563
 564         if (!dev_is_ethdev(dev))
 565                 return NOTIFY_DONE;
 566
 567         switch (event) {
 568         case NETDEV_UP:         /* new ethernet device -> new BPQ interface */
 569                 if (bpq_get_ax25_dev(dev) == NULL)
 570                         bpq_new_device(dev);
 571                 break;
 572
 573         case NETDEV_DOWN:       /* ethernet device closed -> close BPQ interface */
 574                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 575                         dev_close(dev);
 576                 break;
 577
 578         case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
 579                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 580                         bpq_free_device(dev);
 581                 break;
 582         default:
 583                 break;
 584         }
 585
 586         return NOTIFY_DONE;
 587 }
 588
 589
 590 /* ------------------------------------------------------------------------ */
 591
 592 /*
 593  * Initialize driver. To be called from af_ax25 if not compiled as a
 594  * module
 595  */
 596 static int __init bpq_init_driver(void)
 597 {
 598 #ifdef CONFIG_PROC_FS
 599         if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
 600                 printk(KERN_ERR
 601                         "bpq: cannot create /proc/net/bpqether entry.\n");
 602                 return -ENOENT;
 603         }
 604 #endif  /* CONFIG_PROC_FS */
 605
 606         dev_add_pack(&bpq_packet_type);
 607
 608         register_netdevice_notifier(&bpq_dev_notifier);
 609
 610         printk(banner);
 611
 612         return 0;
 613 }
 614
 615 static void __exit bpq_cleanup_driver(void)
 616 {
 617         struct bpqdev *bpq;
 618
 619         dev_remove_pack(&bpq_packet_type);
 620
 621         unregister_netdevice_notifier(&bpq_dev_notifier);
 622
 623         proc_net_remove(&init_net, "bpqether");
 624
 625         rtnl_lock();
 626         while (!list_empty(&bpq_devices)) {
 627                 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
 628                 bpq_free_device(bpq->axdev);
 629         }
 630         rtnl_unlock();
 631 }
 632
 633 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
 634 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
 635 MODULE_LICENSE("GPL");
 636 module_init(bpq_init_driver);
 637 module_exit(bpq_cleanup_driver);