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 /* ------------------------------------------------------------------------ */
 128
 129
 130 /*
 131  *      Get the ethernet device for a BPQ device
 132  */
 133 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
 134 {
 135         struct bpqdev *bpq = netdev_priv(dev);
 136
 137         return bpq ? bpq->ethdev : NULL;
 138 }
 139
 140 /*
 141  *      Get the BPQ device for the ethernet device
 142  */
 143 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
 144 {
 145         struct bpqdev *bpq;
 146
 147         list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
 148                 if (bpq->ethdev == dev)
 149                         return bpq->axdev;
 150         }
 151         return NULL;
 152 }
 153
 154 static inline int dev_is_ethdev(struct net_device *dev)
 155 {
 156         return (
 157                         dev->type == ARPHRD_ETHER
 158                         && strncmp(dev->name, "dummy", 5)
 159         );
 160 }
 161
 162 /* ------------------------------------------------------------------------ */
 163
 164
 165 /*
 166  *      Receive an AX.25 frame via an ethernet interface.
 167  */
 168 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
 169 {
 170         int len;
 171         char * ptr;
 172         struct ethhdr *eth;
 173         struct bpqdev *bpq;
 174
 175         if (dev->nd_net != &init_net)
 176                 goto drop;
 177
 178         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 179                 return NET_RX_DROP;
 180
 181         if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
 182                 goto drop;
 183
 184         rcu_read_lock();
 185         dev = bpq_get_ax25_dev(dev);
 186
 187         if (dev == NULL || !netif_running(dev))
 188                 goto drop_unlock;
 189
 190         /*
 191          * if we want to accept frames from just one ethernet device
 192          * we check the source address of the sender.
 193          */
 194
 195         bpq = netdev_priv(dev);
 196
 197         eth = eth_hdr(skb);
 198
 199         if (!(bpq->acpt_addr[0] & 0x01) &&
 200             memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
 201                 goto drop_unlock;
 202
 203         if (skb_cow(skb, sizeof(struct ethhdr)))
 204                 goto drop_unlock;
 205
 206         len = skb->data[0] + skb->data[1] * 256 - 5;
 207
 208         skb_pull(skb, 2);       /* Remove the length bytes */
 209         skb_trim(skb, len);     /* Set the length of the data */
 210
 211         bpq->stats.rx_packets++;
 212         bpq->stats.rx_bytes += len;
 213
 214         ptr = skb_push(skb, 1);
 215         *ptr = 0;
 216
 217         skb->protocol = ax25_type_trans(skb, dev);
 218         netif_rx(skb);
 219         dev->last_rx = jiffies;
 220 unlock:
 221
 222         rcu_read_unlock();
 223
 224         return 0;
 225 drop_unlock:
 226         kfree_skb(skb);
 227         goto unlock;
 228
 229 drop:
 230         kfree_skb(skb);
 231         return 0;
 232 }
 233
 234 /*
 235  *      Send an AX.25 frame via an ethernet interface
 236  */
 237 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
 238 {
 239         struct sk_buff *newskb;
 240         unsigned char *ptr;
 241         struct bpqdev *bpq;
 242         int size;
 243
 244         /*
 245          * Just to be *really* sure not to send anything if the interface
 246          * is down, the ethernet device may have gone.
 247          */
 248         if (!netif_running(dev)) {
 249                 kfree_skb(skb);
 250                 return -ENODEV;
 251         }
 252
 253         skb_pull(skb, 1);
 254         size = skb->len;
 255
 256         /*
 257          * The AX.25 code leaves enough room for the ethernet header, but
 258          * sendto() does not.
 259          */
 260         if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) {  /* Ough! */
 261                 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
 262                         printk(KERN_WARNING "bpqether: out of memory\n");
 263                         kfree_skb(skb);
 264                         return -ENOMEM;
 265                 }
 266
 267                 if (skb->sk != NULL)
 268                         skb_set_owner_w(newskb, skb->sk);
 269
 270                 kfree_skb(skb);
 271                 skb = newskb;
 272         }
 273
 274         ptr = skb_push(skb, 2);
 275
 276         *ptr++ = (size + 5) % 256;
 277         *ptr++ = (size + 5) / 256;
 278
 279         bpq = netdev_priv(dev);
 280
 281         if ((dev = bpq_get_ether_dev(dev)) == NULL) {
 282                 bpq->stats.tx_dropped++;
 283                 kfree_skb(skb);
 284                 return -ENODEV;
 285         }
 286
 287         skb->protocol = ax25_type_trans(skb, dev);
 288         skb_reset_network_header(skb);
 289         dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
 290         bpq->stats.tx_packets++;
 291         bpq->stats.tx_bytes+=skb->len;
 292
 293         dev_queue_xmit(skb);
 294         netif_wake_queue(dev);
 295         return 0;
 296 }
 297
 298 /*
 299  *      Statistics
 300  */
 301 static struct net_device_stats *bpq_get_stats(struct net_device *dev)
 302 {
 303         struct bpqdev *bpq = netdev_priv(dev);
 304
 305         return &bpq->stats;
 306 }
 307
 308 /*
 309  *      Set AX.25 callsign
 310  */
 311 static int bpq_set_mac_address(struct net_device *dev, void *addr)
 312 {
 313     struct sockaddr *sa = (struct sockaddr *)addr;
 314
 315     memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
 316
 317     return 0;
 318 }
 319
 320 /*      Ioctl commands
 321  *
 322  *              SIOCSBPQETHOPT          reserved for enhancements
 323  *              SIOCSBPQETHADDR         set the destination and accepted
 324  *                                      source ethernet address (broadcast
 325  *                                      or multicast: accept all)
 326  */
 327 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 328 {
 329         struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
 330         struct bpqdev *bpq = netdev_priv(dev);
 331         struct bpq_req req;
 332
 333         if (!capable(CAP_NET_ADMIN))
 334                 return -EPERM;
 335
 336         switch (cmd) {
 337                 case SIOCSBPQETHOPT:
 338                         if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
 339                                 return -EFAULT;
 340                         switch (req.cmd) {
 341                                 case SIOCGBPQETHPARAM:
 342                                 case SIOCSBPQETHPARAM:
 343                                 default:
 344                                         return -EINVAL;
 345                         }
 346
 347                         break;
 348
 349                 case SIOCSBPQETHADDR:
 350                         if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
 351                                 return -EFAULT;
 352                         if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
 353                                 return -EFAULT;
 354                         break;
 355
 356                 default:
 357                         return -EINVAL;
 358         }
 359
 360         return 0;
 361 }
 362
 363 /*
 364  * open/close a device
 365  */
 366 static int bpq_open(struct net_device *dev)
 367 {
 368         netif_start_queue(dev);
 369         return 0;
 370 }
 371
 372 static int bpq_close(struct net_device *dev)
 373 {
 374         netif_stop_queue(dev);
 375         return 0;
 376 }
 377
 378
 379 /* ------------------------------------------------------------------------ */
 380
 381
 382 /*
 383  *      Proc filesystem
 384  */
 385 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
 386 {
 387         int i = 1;
 388         struct bpqdev *bpqdev;
 389
 390         rcu_read_lock();
 391
 392         if (*pos == 0)
 393                 return SEQ_START_TOKEN;
 394
 395         list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
 396                 if (i == *pos)
 397                         return bpqdev;
 398         }
 399         return NULL;
 400 }
 401
 402 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 403 {
 404         struct list_head *p;
 405
 406         ++*pos;
 407
 408         if (v == SEQ_START_TOKEN)
 409                 p = rcu_dereference(bpq_devices.next);
 410         else
 411                 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);
 412
 413         return (p == &bpq_devices) ? NULL
 414                 : list_entry(p, struct bpqdev, bpq_list);
 415 }
 416
 417 static void bpq_seq_stop(struct seq_file *seq, void *v)
 418 {
 419         rcu_read_unlock();
 420 }
 421
 422
 423 static int bpq_seq_show(struct seq_file *seq, void *v)
 424 {
 425         if (v == SEQ_START_TOKEN)
 426                 seq_puts(seq,
 427                          "dev   ether      destination        accept from\n");
 428         else {
 429                 const struct bpqdev *bpqdev = v;
 430                 DECLARE_MAC_BUF(mac);
 431
 432                 seq_printf(seq, "%-5s %-10s %s  ",
 433                         bpqdev->axdev->name, bpqdev->ethdev->name,
 434                         print_mac(mac, bpqdev->dest_addr));
 435
 436                 if (is_multicast_ether_addr(bpqdev->acpt_addr))
 437                         seq_printf(seq, "*\n");
 438                 else
 439                         seq_printf(seq, "%s\n", print_mac(mac, bpqdev->acpt_addr));
 440
 441         }
 442         return 0;
 443 }
 444
 445 static struct seq_operations bpq_seqops = {
 446         .start = bpq_seq_start,
 447         .next = bpq_seq_next,
 448         .stop = bpq_seq_stop,
 449         .show = bpq_seq_show,
 450 };
 451
 452 static int bpq_info_open(struct inode *inode, struct file *file)
 453 {
 454         return seq_open(file, &bpq_seqops);
 455 }
 456
 457 static const struct file_operations bpq_info_fops = {
 458         .owner = THIS_MODULE,
 459         .open = bpq_info_open,
 460         .read = seq_read,
 461         .llseek = seq_lseek,
 462         .release = seq_release,
 463 };
 464
 465
 466 /* ------------------------------------------------------------------------ */
 467
 468
 469 static void bpq_setup(struct net_device *dev)
 470 {
 471
 472         dev->hard_start_xmit = bpq_xmit;
 473         dev->open            = bpq_open;
 474         dev->stop            = bpq_close;
 475         dev->set_mac_address = bpq_set_mac_address;
 476         dev->get_stats       = bpq_get_stats;
 477         dev->do_ioctl        = bpq_ioctl;
 478         dev->destructor      = free_netdev;
 479
 480         memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
 481         memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);
 482
 483         dev->flags      = 0;
 484
 485 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
 486         dev->hard_header     = ax25_hard_header;
 487         dev->rebuild_header  = ax25_rebuild_header;
 488 #endif
 489
 490         dev->type            = ARPHRD_AX25;
 491         dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
 492         dev->mtu             = AX25_DEF_PACLEN;
 493         dev->addr_len        = AX25_ADDR_LEN;
 494
 495 }
 496
 497 /*
 498  *      Setup a new device.
 499  */
 500 static int bpq_new_device(struct net_device *edev)
 501 {
 502         int err;
 503         struct net_device *ndev;
 504         struct bpqdev *bpq;
 505
 506         ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
 507                            bpq_setup);
 508         if (!ndev)
 509                 return -ENOMEM;
 510
 511
 512         bpq = netdev_priv(ndev);
 513         dev_hold(edev);
 514         bpq->ethdev = edev;
 515         bpq->axdev = ndev;
 516
 517         memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
 518         memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
 519
 520         err = dev_alloc_name(ndev, ndev->name);
 521         if (err < 0)
 522                 goto error;
 523
 524         err = register_netdevice(ndev);
 525         if (err)
 526                 goto error;
 527         lockdep_set_class(&ndev->_xmit_lock, &bpq_netdev_xmit_lock_key);
 528
 529         /* List protected by RTNL */
 530         list_add_rcu(&bpq->bpq_list, &bpq_devices);
 531         return 0;
 532
 533  error:
 534         dev_put(edev);
 535         free_netdev(ndev);
 536         return err;
 537
 538 }
 539
 540 static void bpq_free_device(struct net_device *ndev)
 541 {
 542         struct bpqdev *bpq = netdev_priv(ndev);
 543
 544         dev_put(bpq->ethdev);
 545         list_del_rcu(&bpq->bpq_list);
 546
 547         unregister_netdevice(ndev);
 548 }
 549
 550 /*
 551  *      Handle device status changes.
 552  */
 553 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 554 {
 555         struct net_device *dev = (struct net_device *)ptr;
 556
 557         if (dev->nd_net != &init_net)
 558                 return NOTIFY_DONE;
 559
 560         if (!dev_is_ethdev(dev))
 561                 return NOTIFY_DONE;
 562
 563         switch (event) {
 564         case NETDEV_UP:         /* new ethernet device -> new BPQ interface */
 565                 if (bpq_get_ax25_dev(dev) == NULL)
 566                         bpq_new_device(dev);
 567                 break;
 568
 569         case NETDEV_DOWN:       /* ethernet device closed -> close BPQ interface */
 570                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 571                         dev_close(dev);
 572                 break;
 573
 574         case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
 575                 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
 576                         bpq_free_device(dev);
 577                 break;
 578         default:
 579                 break;
 580         }
 581
 582         return NOTIFY_DONE;
 583 }
 584
 585
 586 /* ------------------------------------------------------------------------ */
 587
 588 /*
 589  * Initialize driver. To be called from af_ax25 if not compiled as a
 590  * module
 591  */
 592 static int __init bpq_init_driver(void)
 593 {
 594 #ifdef CONFIG_PROC_FS
 595         if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
 596                 printk(KERN_ERR
 597                         "bpq: cannot create /proc/net/bpqether entry.\n");
 598                 return -ENOENT;
 599         }
 600 #endif  /* CONFIG_PROC_FS */
 601
 602         dev_add_pack(&bpq_packet_type);
 603
 604         register_netdevice_notifier(&bpq_dev_notifier);
 605
 606         printk(banner);
 607
 608         return 0;
 609 }
 610
 611 static void __exit bpq_cleanup_driver(void)
 612 {
 613         struct bpqdev *bpq;
 614
 615         dev_remove_pack(&bpq_packet_type);
 616
 617         unregister_netdevice_notifier(&bpq_dev_notifier);
 618
 619         proc_net_remove(&init_net, "bpqether");
 620
 621         rtnl_lock();
 622         while (!list_empty(&bpq_devices)) {
 623                 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
 624                 bpq_free_device(bpq->axdev);
 625         }
 626         rtnl_unlock();
 627 }
 628
 629 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
 630 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
 631 MODULE_LICENSE("GPL");
 632 module_init(bpq_init_driver);
 633 module_exit(bpq_cleanup_driver);