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/if_ether.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 static const char *bpq_print_ethaddr(const unsigned char *);
  99
 100 static struct packet_type bpq_packet_type = {
 101         .type   = __constant_htons(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         struct net_device_stats stats;  /* some statistics */
 115         char   dest_addr[6];            /* ether destination address */
 116         char   acpt_addr[6];            /* accept ether frames from this address only */
 117 };
 118
 119 static LIST_HEAD(bpq_devices);
 120
 121 /*
 122  * bpqether network devices are paired with ethernet devices below them, so
 123  * form a special "super class" of normal ethernet devices; split their locks
 124  * off into a separate class since they always nest.
 125  */
 126 static struct lock_class_key bpq_netdev_xmit_lock_key;
 127
 128 /* ------------------------------------------------------------------------ */
 129
 130
 131 /*
 132  *      Get the ethernet device for a BPQ device
 133  */
 134 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
 135 {
 136         struct bpqdev *bpq = netdev_priv(dev);
 137
 138         return bpq ? bpq->ethdev : NULL;
 139 }
 140
 141 /*
 142  *      Get the BPQ device for the ethernet device
 143  */
 144 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
 145 {
 146         struct bpqdev *bpq;
 147
 148         list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
 149                 if (bpq->ethdev == dev)
 150                         return bpq->axdev;
 151         }
 152         return NULL;
 153 }
 154
 155 static inline int dev_is_ethdev(struct net_device *dev)
 156 {
 157         return (
 158                         dev->type == ARPHRD_ETHER
 159                         && strncmp(dev->name, "dummy", 5)
 160         );
 161 }
 162
 163 /* ------------------------------------------------------------------------ */
 164
 165
 166 /*
 167  *      Receive an AX.25 frame via an ethernet interface.
 168  */
 169 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
 170 {
 171         int len;
 172         char * ptr;
 173         struct ethhdr *eth;
 174         struct bpqdev *bpq;
 175
 176         if (dev->nd_net != &init_net)
 177                 goto drop;
 178
 179         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 180                 return NET_RX_DROP;
 181
 182         if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
 183                 goto drop;
 184
 185         rcu_read_lock();
 186         dev = bpq_get_ax25_dev(dev);
 187
 188         if (dev == NULL || !netif_running(dev))
 189                 goto drop_unlock;
 190
 191         /*
 192          * if we want to accept frames from just one ethernet device
 193          * we check the source address of the sender.
 194          */
 195
 196         bpq = netdev_priv(dev);
 197
 198         eth = eth_hdr(skb);
 199
 200         if (!(bpq->acpt_addr[0] & 0x01) &&
 201             memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
 202                 goto drop_unlock;
 203
 204         if (skb_cow(skb, sizeof(struct ethhdr)))
 205                 goto drop_unlock;
 206
 207         len = skb->data[0] + skb->data[1] * 256 - 5;
 208
 209         skb_pull(skb, 2);       /* Remove the length bytes */
 210         skb_trim(skb, len);     /* Set the length of the data */
 211
 212         bpq->stats.rx_packets++;
 213         bpq->stats.rx_bytes += len;
 214
 215         ptr = skb_push(skb, 1);
 216         *ptr = 0;
 217
 218         skb->protocol = ax25_type_trans(skb, dev);
 219         netif_rx(skb);
 220         dev->last_rx = jiffies;
 221 unlock:
 222
 223         rcu_read_unlock();
 224
 225         return 0;
 226 drop_unlock:
 227         kfree_skb(skb);
 228         goto unlock;
 229
 230 drop:
 231         kfree_skb(skb);
 232         return 0;
 233 }
 234
 235 /*
 236  *      Send an AX.25 frame via an ethernet interface
 237  */
 238 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
 239 {
 240         struct sk_buff *newskb;
 241         unsigned char *ptr;
 242         struct bpqdev *bpq;
 243         int size;
 244
 245         /*
 246          * Just to be *really* sure not to send anything if the interface
 247          * is down, the ethernet device may have gone.
 248          */
 249         if (!netif_running(dev)) {
 250                 kfree_skb(skb);
 251                 return -ENODEV;
 252         }
 253
 254         skb_pull(skb, 1);
 255         size = skb->len;
 256
 257         /*
 258          * The AX.25 code leaves enough room for the ethernet header, but
 259          * sendto() does not.
 260          */
 261         if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {  /* Ough! */
 262                 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
 263                         printk(KERN_WARNING "bpqether: out of memory\n");
 264                         kfree_skb(skb);
 265                         return -ENOMEM;
 266                 }
 267
 268                 if (skb->sk != NULL)
 269                         skb_set_owner_w(newskb, skb->sk);
 270
 271                 kfree_skb(skb);
 272                 skb = newskb;
 273         }
 274
 275         ptr = skb_push(skb, 2);
 276
 277         *ptr++ = (size + 5) % 256;
 278         *ptr++ = (size + 5) / 256;
 279
 280         bpq = netdev_priv(dev);
 281
 282         if ((dev = bpq_get_ether_dev(dev)) == NULL) {
 283                 bpq->stats.tx_dropped++;
 284                 kfree_skb(skb);
 285                 return -ENODEV;
 286         }
 287
 288         skb->protocol = ax25_type_trans(skb, dev);
 289         skb_reset_network_header(skb);
 290         dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 291         bpq->stats.tx_packets++;
 292         bpq->stats.tx_bytes+=skb->len;
 293
 294         dev_queue_xmit(skb);
 295         netif_wake_queue(dev);
 296         return 0;
 297 }
 298
 299 /*
 300  *      Statistics
 301  */
 302 static struct net_device_stats *bpq_get_stats(struct net_device *dev)
 303 {
 304         struct bpqdev *bpq = netdev_priv(dev);
 305
 306         return &bpq->stats;
 307 }
 308
 309 /*
 310  *      Set AX.25 callsign
 311  */
 312 static int bpq_set_mac_address(struct net_device *dev, void *addr)
 313 {
 314     struct sockaddr *sa = (struct sockaddr *)addr;
 315
 316     memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 317
 318     return 0;
 319 }
 320
 321 /*      Ioctl commands
 322  *
 323  *              SIOCSBPQETHOPT          reserved for enhancements
 324  *              SIOCSBPQETHADDR         set the destination and accepted
 325  *                                      source ethernet address (broadcast
 326  *                                      or multicast: accept all)
 327  */
 328 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 329 {
 330         struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
 331         struct bpqdev *bpq = netdev_priv(dev);
 332         struct bpq_req req;
 333
 334         if (!capable(CAP_NET_ADMIN))
 335                 return -EPERM;
 336
 337         switch (cmd) {
 338                 case SIOCSBPQETHOPT:
 339                         if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
 340                                 return -EFAULT;
 341                         switch (req.cmd) {
 342                                 case SIOCGBPQETHPARAM:
 343                                 case SIOCSBPQETHPARAM:
 344                                 default:
 345                                         return -EINVAL;
 346                         }
 347
 348                         break;
 349
 350                 case SIOCSBPQETHADDR:
 351                         if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
 352                                 return -EFAULT;
 353                         if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
 354                                 return -EFAULT;
 355                         break;
 356
 357                 default:
 358                         return -EINVAL;
 359         }
 360
 361         return 0;
 362 }
 363
 364 /*
 365  * open/close a device
 366  */
 367 static int bpq_open(struct net_device *dev)
 368 {
 369         netif_start_queue(dev);
 370         return 0;
 371 }
 372
 373 static int bpq_close(struct net_device *dev)
 374 {
 375         netif_stop_queue(dev);
 376         return 0;
 377 }
 378
 379
 380 /* ------------------------------------------------------------------------ */
 381
 382
 383 /*
 384  *      Proc filesystem
 385  */
 386 static const char * bpq_print_ethaddr(const unsigned char *e)
 387 {
 388         static char buf[18];
 389
 390         sprintf(buf, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
 391                 e[0], e[1], e[2], e[3], e[4], e[5]);
 392
 393         return buf;
 394 }
 395
 396 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
 397 {
 398         int i = 1;
 399         struct bpqdev *bpqdev;
 400
 401         rcu_read_lock();
 402
 403         if (*pos == 0)
 404                 return SEQ_START_TOKEN;
 405
 406         list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
 407                 if (i == *pos)
 408                         return bpqdev;
 409         }
 410         return NULL;
 411 }
 412
 413 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 414 {
 415         struct list_head *p;
 416
 417         ++*pos;
 418
 419         if (v == SEQ_START_TOKEN)
 420                 p = rcu_dereference(bpq_devices.next);
 421         else
 422                 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);
 423
 424         return (p == &bpq_devices) ? NULL
 425                 : list_entry(p, struct bpqdev, bpq_list);
 426 }
 427
 428 static void bpq_seq_stop(struct seq_file *seq, void *v)
 429 {
 430         rcu_read_unlock();
 431 }
 432
 433
 434 static int bpq_seq_show(struct seq_file *seq, void *v)
 435 {
 436         if (v == SEQ_START_TOKEN)
 437                 seq_puts(seq,
 438                          "dev   ether      destination        accept from\n");
 439         else {
 440                 const struct bpqdev *bpqdev = v;
 441
 442                 seq_printf(seq, "%-5s %-10s %s  ",
 443                         bpqdev->axdev->name, bpqdev->ethdev->name,
 444                         bpq_print_ethaddr(bpqdev->dest_addr));
 445
 446                 seq_printf(seq, "%s\n",
 447                         (bpqdev->acpt_addr[0] & 0x01) ? "*"
 448                            : bpq_print_ethaddr(bpqdev->acpt_addr));
 449
 450         }
 451         return 0;
 452 }
 453
 454 static struct seq_operations bpq_seqops = {
 455         .start = bpq_seq_start,
 456         .next = bpq_seq_next,
 457         .stop = bpq_seq_stop,
 458         .show = bpq_seq_show,
 459 };
 460
 461 static int bpq_info_open(struct inode *inode, struct file *file)
 462 {
 463         return seq_open(file, &bpq_seqops);
 464 }
 465
 466 static const struct file_operations bpq_info_fops = {
 467         .owner = THIS_MODULE,
 468         .open = bpq_info_open,
 469         .read = seq_read,
 470         .llseek = seq_lseek,
 471         .release = seq_release,
 472 };
 473
 474
 475 /* ------------------------------------------------------------------------ */
 476
 477
 478 static void bpq_setup(struct net_device *dev)
 479 {
 480
 481         dev->hard_start_xmit = bpq_xmit;
 482         dev->open            = bpq_open;
 483         dev->stop            = bpq_close;
 484         dev->set_mac_address = bpq_set_mac_address;
 485         dev->get_stats       = bpq_get_stats;
 486         dev->do_ioctl        = bpq_ioctl;
 487         dev->destructor      = free_netdev;
 488
 489         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 490         memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);
 491
 492         dev->flags      = 0;
 493
 494 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
 495         dev->hard_header     = ax25_hard_header;
 496         dev->rebuild_header  = ax25_rebuild_header;
 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         lockdep_set_class(&ndev->_xmit_lock, &bpq_netdev_xmit_lock_key);
 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->nd_net != &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);