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
  87 #include <linux/bpqether.h>
  88
  89 static char banner[] __initdata = KERN_INFO "AX.25: bpqether driver version 004\n";
  90
  91 static unsigned char ax25_bcast[AX25_ADDR_LEN] =
  92         {'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
  93 static unsigned char ax25_defaddr[AX25_ADDR_LEN] =
  94         {'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};
  95
  96 static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
  97
  98 static char bpq_eth_addr[6];
  99
 100 static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
 101 static int bpq_device_event(struct notifier_block *, unsigned long, void *);
 102 static const char *bpq_print_ethaddr(const unsigned char *);
 103
 104 static struct packet_type bpq_packet_type = {
 105         .type   = __constant_htons(ETH_P_BPQ),
 106         .func   = bpq_rcv,
 107 };
 108
 109 static struct notifier_block bpq_dev_notifier = {
 110         .notifier_call =bpq_device_event,
 111 };
 112
 113
 114 struct bpqdev {
 115         struct list_head bpq_list;      /* list of bpq devices chain */
 116         struct net_device *ethdev;      /* link to ethernet device */
 117         struct net_device *axdev;       /* bpq device (bpq#) */
 118         struct net_device_stats stats;  /* some statistics */
 119         char   dest_addr[6];            /* ether destination address */
 120         char   acpt_addr[6];            /* accept ether frames from this address only */
 121 };
 122
 123 static LIST_HEAD(bpq_devices);
 124
 125 /*
 126  * bpqether network devices are paired with ethernet devices below them, so
 127  * form a special "super class" of normal ethernet devices; split their locks
 128  * off into a separate class since they always nest.
 129  */
 130 static struct lock_class_key bpq_netdev_xmit_lock_key;
 131
 132 /* ------------------------------------------------------------------------ */
 133
 134
 135 /*
 136  *      Get the ethernet device for a BPQ device
 137  */
 138 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
 139 {
 140         struct bpqdev *bpq = netdev_priv(dev);
 141
 142         return bpq ? bpq->ethdev : NULL;
 143 }
 144
 145 /*
 146  *      Get the BPQ device for the ethernet device
 147  */
 148 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
 149 {
 150         struct bpqdev *bpq;
 151
 152         list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
 153                 if (bpq->ethdev == dev)
 154                         return bpq->axdev;
 155         }
 156         return NULL;
 157 }
 158
 159 static inline int dev_is_ethdev(struct net_device *dev)
 160 {
 161         return (
 162                         dev->type == ARPHRD_ETHER
 163                         && strncmp(dev->name, "dummy", 5)
 164         );
 165 }
 166
 167 /* ------------------------------------------------------------------------ */
 168
 169
 170 /*
 171  *      Receive an AX.25 frame via an ethernet interface.
 172  */
 173 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
 174 {
 175         int len;
 176         char * ptr;
 177         struct ethhdr *eth;
 178         struct bpqdev *bpq;
 179
 180         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 181                 return NET_RX_DROP;
 182
 183         if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
 184                 goto drop;
 185
 186         rcu_read_lock();
 187         dev = bpq_get_ax25_dev(dev);
 188
 189         if (dev == NULL || !netif_running(dev))
 190                 goto drop_unlock;
 191
 192         /*
 193          * if we want to accept frames from just one ethernet device
 194          * we check the source address of the sender.
 195          */
 196
 197         bpq = netdev_priv(dev);
 198
 199         eth = eth_hdr(skb);
 200
 201         if (!(bpq->acpt_addr[0] & 0x01) &&
 202             memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
 203                 goto drop_unlock;
 204
 205         if (skb_cow(skb, sizeof(struct ethhdr)))
 206                 goto drop_unlock;
 207
 208         len = skb->data[0] + skb->data[1] * 256 - 5;
 209
 210         skb_pull(skb, 2);       /* Remove the length bytes */
 211         skb_trim(skb, len);     /* Set the length of the data */
 212
 213         bpq->stats.rx_packets++;
 214         bpq->stats.rx_bytes += len;
 215
 216         ptr = skb_push(skb, 1);
 217         *ptr = 0;
 218
 219         skb->protocol = ax25_type_trans(skb, dev);
 220         netif_rx(skb);
 221         dev->last_rx = jiffies;
 222 unlock:
 223
 224         rcu_read_unlock();
 225
 226         return 0;
 227 drop_unlock:
 228         kfree_skb(skb);
 229         goto unlock;
 230
 231 drop:
 232         kfree_skb(skb);
 233         return 0;
 234 }
 235
 236 /*
 237  *      Send an AX.25 frame via an ethernet interface
 238  */
 239 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
 240 {
 241         struct sk_buff *newskb;
 242         unsigned char *ptr;
 243         struct bpqdev *bpq;
 244         int size;
 245
 246         /*
 247          * Just to be *really* sure not to send anything if the interface
 248          * is down, the ethernet device may have gone.
 249          */
 250         if (!netif_running(dev)) {
 251                 kfree_skb(skb);
 252                 return -ENODEV;
 253         }
 254
 255         skb_pull(skb, 1);
 256         size = skb->len;
 257
 258         /*
 259          * The AX.25 code leaves enough room for the ethernet header, but
 260          * sendto() does not.
 261          */
 262         if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {  /* Ough! */
 263                 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
 264                         printk(KERN_WARNING "bpqether: out of memory\n");
 265                         kfree_skb(skb);
 266                         return -ENOMEM;
 267                 }
 268
 269                 if (skb->sk != NULL)
 270                         skb_set_owner_w(newskb, skb->sk);
 271
 272                 kfree_skb(skb);
 273                 skb = newskb;
 274         }
 275
 276         ptr = skb_push(skb, 2);
 277
 278         *ptr++ = (size + 5) % 256;
 279         *ptr++ = (size + 5) / 256;
 280
 281         bpq = netdev_priv(dev);
 282
 283         if ((dev = bpq_get_ether_dev(dev)) == NULL) {
 284                 bpq->stats.tx_dropped++;
 285                 kfree_skb(skb);
 286                 return -ENODEV;
 287         }
 288
 289         skb->protocol = ax25_type_trans(skb, dev);
 290         skb->nh.raw = skb->data;
 291         dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 292         bpq->stats.tx_packets++;
 293         bpq->stats.tx_bytes+=skb->len;
 294
 295         dev_queue_xmit(skb);
 296         netif_wake_queue(dev);
 297         return 0;
 298 }
 299
 300 /*
 301  *      Statistics
 302  */
 303 static struct net_device_stats *bpq_get_stats(struct net_device *dev)
 304 {
 305         struct bpqdev *bpq = netdev_priv(dev);
 306
 307         return &bpq->stats;
 308 }
 309
 310 /*
 311  *      Set AX.25 callsign
 312  */
 313 static int bpq_set_mac_address(struct net_device *dev, void *addr)
 314 {
 315     struct sockaddr *sa = (struct sockaddr *)addr;
 316
 317     memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 318
 319     return 0;
 320 }
 321
 322 /*      Ioctl commands
 323  *
 324  *              SIOCSBPQETHOPT          reserved for enhancements
 325  *              SIOCSBPQETHADDR         set the destination and accepted
 326  *                                      source ethernet address (broadcast
 327  *                                      or multicast: accept all)
 328  */
 329 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 330 {
 331         struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
 332         struct bpqdev *bpq = netdev_priv(dev);
 333         struct bpq_req req;
 334
 335         if (!capable(CAP_NET_ADMIN))
 336                 return -EPERM;
 337
 338         switch (cmd) {
 339                 case SIOCSBPQETHOPT:
 340                         if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
 341                                 return -EFAULT;
 342                         switch (req.cmd) {
 343                                 case SIOCGBPQETHPARAM:
 344                                 case SIOCSBPQETHPARAM:
 345                                 default:
 346                                         return -EINVAL;
 347                         }
 348
 349                         break;
 350
 351                 case SIOCSBPQETHADDR:
 352                         if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
 353                                 return -EFAULT;
 354                         if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
 355                                 return -EFAULT;
 356                         break;
 357
 358                 default:
 359                         return -EINVAL;
 360         }
 361
 362         return 0;
 363 }
 364
 365 /*
 366  * open/close a device
 367  */
 368 static int bpq_open(struct net_device *dev)
 369 {
 370         netif_start_queue(dev);
 371         return 0;
 372 }
 373
 374 static int bpq_close(struct net_device *dev)
 375 {
 376         netif_stop_queue(dev);
 377         return 0;
 378 }
 379
 380
 381 /* ------------------------------------------------------------------------ */
 382
 383
 384 /*
 385  *      Proc filesystem
 386  */
 387 static const char * bpq_print_ethaddr(const unsigned char *e)
 388 {
 389         static char buf[18];
 390
 391         sprintf(buf, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
 392                 e[0], e[1], e[2], e[3], e[4], e[5]);
 393
 394         return buf;
 395 }
 396
 397 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
 398 {
 399         int i = 1;
 400         struct bpqdev *bpqdev;
 401
 402         rcu_read_lock();
 403
 404         if (*pos == 0)
 405                 return SEQ_START_TOKEN;
 406
 407         list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
 408                 if (i == *pos)
 409                         return bpqdev;
 410         }
 411         return NULL;
 412 }
 413
 414 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 415 {
 416         struct list_head *p;
 417
 418         ++*pos;
 419
 420         if (v == SEQ_START_TOKEN)
 421                 p = bpq_devices.next;
 422         else
 423                 p = ((struct bpqdev *)v)->bpq_list.next;
 424
 425         return (p == &bpq_devices) ? NULL
 426                 : rcu_dereference(list_entry(p, struct bpqdev, bpq_list));
 427 }
 428
 429 static void bpq_seq_stop(struct seq_file *seq, void *v)
 430 {
 431         rcu_read_unlock();
 432 }
 433
 434
 435 static int bpq_seq_show(struct seq_file *seq, void *v)
 436 {
 437         if (v == SEQ_START_TOKEN)
 438                 seq_puts(seq,
 439                          "dev   ether      destination        accept from\n");
 440         else {
 441                 const struct bpqdev *bpqdev = v;
 442
 443                 seq_printf(seq, "%-5s %-10s %s  ",
 444                         bpqdev->axdev->name, bpqdev->ethdev->name,
 445                         bpq_print_ethaddr(bpqdev->dest_addr));
 446
 447                 seq_printf(seq, "%s\n",
 448                         (bpqdev->acpt_addr[0] & 0x01) ? "*"
 449                            : bpq_print_ethaddr(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 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->hard_header     = ax25_hard_header;
 497         dev->rebuild_header  = ax25_rebuild_header;
 498 #endif
 499
 500         dev->type            = ARPHRD_AX25;
 501         dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
 502         dev->mtu             = AX25_DEF_PACLEN;
 503         dev->addr_len        = AX25_ADDR_LEN;
 504
 505 }
 506
 507 /*
 508  *      Setup a new device.
 509  */
 510 static int bpq_new_device(struct net_device *edev)
 511 {
 512         int err;
 513         struct net_device *ndev;
 514         struct bpqdev *bpq;
 515
 516         ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
 517                            bpq_setup);
 518         if (!ndev)
 519                 return -ENOMEM;
 520
 521
 522         bpq = netdev_priv(ndev);
 523         dev_hold(edev);
 524         bpq->ethdev = edev;
 525         bpq->axdev = ndev;
 526
 527         memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
 528         memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
 529
 530         err = dev_alloc_name(ndev, ndev->name);
 531         if (err < 0)
 532                 goto error;
 533
 534         err = register_netdevice(ndev);
 535         if (err)
 536                 goto error;
 537         lockdep_set_class(&ndev->_xmit_lock, &bpq_netdev_xmit_lock_key);
 538
 539         /* List protected by RTNL */
 540         list_add_rcu(&bpq->bpq_list, &bpq_devices);
 541         return 0;
 542
 543  error:
 544         dev_put(edev);
 545         free_netdev(ndev);
 546         return err;
 547
 548 }
 549
 550 static void bpq_free_device(struct net_device *ndev)
 551 {
 552         struct bpqdev *bpq = netdev_priv(ndev);
 553
 554         dev_put(bpq->ethdev);
 555         list_del_rcu(&bpq->bpq_list);
 556
 557         unregister_netdevice(ndev);
 558 }
 559
 560 /*
 561  *      Handle device status changes.
 562  */
 563 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 564 {
 565         struct net_device *dev = (struct net_device *)ptr;
 566
 567         if (!dev_is_ethdev(dev))
 568                 return NOTIFY_DONE;
 569
 570         switch (event) {
 571         case NETDEV_UP:         /* new ethernet device -> new BPQ interface */
 572                 if (bpq_get_ax25_dev(dev) == NULL)
 573                         bpq_new_device(dev);
 574                 break;
 575
 576         case NETDEV_DOWN:       /* ethernet device closed -> close BPQ interface */
 577                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 578                         dev_close(dev);
 579                 break;
 580
 581         case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
 582                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 583                         bpq_free_device(dev);
 584                 break;
 585         default:
 586                 break;
 587         }
 588
 589         return NOTIFY_DONE;
 590 }
 591
 592
 593 /* ------------------------------------------------------------------------ */
 594
 595 /*
 596  * Initialize driver. To be called from af_ax25 if not compiled as a
 597  * module
 598  */
 599 static int __init bpq_init_driver(void)
 600 {
 601 #ifdef CONFIG_PROC_FS
 602         if (!proc_net_fops_create("bpqether", S_IRUGO, &bpq_info_fops)) {
 603                 printk(KERN_ERR
 604                         "bpq: cannot create /proc/net/bpqether entry.\n");
 605                 return -ENOENT;
 606         }
 607 #endif  /* CONFIG_PROC_FS */
 608
 609         dev_add_pack(&bpq_packet_type);
 610
 611         register_netdevice_notifier(&bpq_dev_notifier);
 612
 613         printk(banner);
 614
 615         return 0;
 616 }
 617
 618 static void __exit bpq_cleanup_driver(void)
 619 {
 620         struct bpqdev *bpq;
 621
 622         dev_remove_pack(&bpq_packet_type);
 623
 624         unregister_netdevice_notifier(&bpq_dev_notifier);
 625
 626         proc_net_remove("bpqether");
 627
 628         rtnl_lock();
 629         while (!list_empty(&bpq_devices)) {
 630                 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
 631                 bpq_free_device(bpq->axdev);
 632         }
 633         rtnl_unlock();
 634 }
 635
 636 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
 637 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
 638 MODULE_LICENSE("GPL");
 639 module_init(bpq_init_driver);
 640 module_exit(bpq_cleanup_driver);