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 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 bpq->stats.rx_packets++; 226 bpq->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 bpq->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 bpq->stats.tx_packets++; 304 bpq->stats.tx_bytes+=skb->len; 305 306 dev_queue_xmit(skb); 307 netif_wake_queue(dev); 308 return 0; 309 } 310 311 /* 312 * Statistics 313 */ 314 static struct net_device_stats *bpq_get_stats(struct net_device *dev) 315 { 316 struct bpqdev *bpq = netdev_priv(dev); 317 318 return &bpq->stats; 319 } 320 321 /* 322 * Set AX.25 callsign 323 */ 324 static int bpq_set_mac_address(struct net_device *dev, void *addr) 325 { 326 struct sockaddr *sa = (struct sockaddr *)addr; 327 328 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 329 330 return 0; 331 } 332 333 /* Ioctl commands 334 * 335 * SIOCSBPQETHOPT reserved for enhancements 336 * SIOCSBPQETHADDR set the destination and accepted 337 * source ethernet address (broadcast 338 * or multicast: accept all) 339 */ 340 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 341 { 342 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data; 343 struct bpqdev *bpq = netdev_priv(dev); 344 struct bpq_req req; 345 346 if (!capable(CAP_NET_ADMIN)) 347 return -EPERM; 348 349 switch (cmd) { 350 case SIOCSBPQETHOPT: 351 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req))) 352 return -EFAULT; 353 switch (req.cmd) { 354 case SIOCGBPQETHPARAM: 355 case SIOCSBPQETHPARAM: 356 default: 357 return -EINVAL; 358 } 359 360 break; 361 362 case SIOCSBPQETHADDR: 363 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN)) 364 return -EFAULT; 365 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN)) 366 return -EFAULT; 367 break; 368 369 default: 370 return -EINVAL; 371 } 372 373 return 0; 374 } 375 376 /* 377 * open/close a device 378 */ 379 static int bpq_open(struct net_device *dev) 380 { 381 netif_start_queue(dev); 382 return 0; 383 } 384 385 static int bpq_close(struct net_device *dev) 386 { 387 netif_stop_queue(dev); 388 return 0; 389 } 390 391 392 /* ------------------------------------------------------------------------ */ 393 394 395 /* 396 * Proc filesystem 397 */ 398 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos) 399 { 400 int i = 1; 401 struct bpqdev *bpqdev; 402 403 rcu_read_lock(); 404 405 if (*pos == 0) 406 return SEQ_START_TOKEN; 407 408 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) { 409 if (i == *pos) 410 return bpqdev; 411 } 412 return NULL; 413 } 414 415 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos) 416 { 417 struct list_head *p; 418 419 ++*pos; 420 421 if (v == SEQ_START_TOKEN) 422 p = rcu_dereference(bpq_devices.next); 423 else 424 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next); 425 426 return (p == &bpq_devices) ? NULL 427 : list_entry(p, struct bpqdev, bpq_list); 428 } 429 430 static void bpq_seq_stop(struct seq_file *seq, void *v) 431 { 432 rcu_read_unlock(); 433 } 434 435 436 static int bpq_seq_show(struct seq_file *seq, void *v) 437 { 438 if (v == SEQ_START_TOKEN) 439 seq_puts(seq, 440 "dev ether destination accept from\n"); 441 else { 442 const struct bpqdev *bpqdev = v; 443 444 seq_printf(seq, "%-5s %-10s %pM ", 445 bpqdev->axdev->name, bpqdev->ethdev->name, 446 bpqdev->dest_addr); 447 448 if (is_multicast_ether_addr(bpqdev->acpt_addr)) 449 seq_printf(seq, "*\n"); 450 else 451 seq_printf(seq, "%pM\n", bpqdev->acpt_addr); 452 453 } 454 return 0; 455 } 456 457 static struct seq_operations bpq_seqops = { 458 .start = bpq_seq_start, 459 .next = bpq_seq_next, 460 .stop = bpq_seq_stop, 461 .show = bpq_seq_show, 462 }; 463 464 static int bpq_info_open(struct inode *inode, struct file *file) 465 { 466 return seq_open(file, &bpq_seqops); 467 } 468 469 static const struct file_operations bpq_info_fops = { 470 .owner = THIS_MODULE, 471 .open = bpq_info_open, 472 .read = seq_read, 473 .llseek = seq_lseek, 474 .release = seq_release, 475 }; 476 477 478 /* ------------------------------------------------------------------------ */ 479 480 481 static void bpq_setup(struct net_device *dev) 482 { 483 484 dev->hard_start_xmit = bpq_xmit; 485 dev->open = bpq_open; 486 dev->stop = bpq_close; 487 dev->set_mac_address = bpq_set_mac_address; 488 dev->get_stats = bpq_get_stats; 489 dev->do_ioctl = bpq_ioctl; 490 dev->destructor = free_netdev; 491 492 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); 493 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); 494 495 dev->flags = 0; 496 497 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 498 dev->header_ops = &ax25_header_ops; 499 #endif 500 501 dev->type = ARPHRD_AX25; 502 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN; 503 dev->mtu = AX25_DEF_PACLEN; 504 dev->addr_len = AX25_ADDR_LEN; 505 506 } 507 508 /* 509 * Setup a new device. 510 */ 511 static int bpq_new_device(struct net_device *edev) 512 { 513 int err; 514 struct net_device *ndev; 515 struct bpqdev *bpq; 516 517 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", 518 bpq_setup); 519 if (!ndev) 520 return -ENOMEM; 521 522 523 bpq = netdev_priv(ndev); 524 dev_hold(edev); 525 bpq->ethdev = edev; 526 bpq->axdev = ndev; 527 528 memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr)); 529 memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr)); 530 531 err = dev_alloc_name(ndev, ndev->name); 532 if (err < 0) 533 goto error; 534 535 err = register_netdevice(ndev); 536 if (err) 537 goto error; 538 bpq_set_lockdep_class(ndev); 539 540 /* List protected by RTNL */ 541 list_add_rcu(&bpq->bpq_list, &bpq_devices); 542 return 0; 543 544 error: 545 dev_put(edev); 546 free_netdev(ndev); 547 return err; 548 549 } 550 551 static void bpq_free_device(struct net_device *ndev) 552 { 553 struct bpqdev *bpq = netdev_priv(ndev); 554 555 dev_put(bpq->ethdev); 556 list_del_rcu(&bpq->bpq_list); 557 558 unregister_netdevice(ndev); 559 } 560 561 /* 562 * Handle device status changes. 563 */ 564 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr) 565 { 566 struct net_device *dev = (struct net_device *)ptr; 567 568 if (dev_net(dev) != &init_net) 569 return NOTIFY_DONE; 570 571 if (!dev_is_ethdev(dev)) 572 return NOTIFY_DONE; 573 574 switch (event) { 575 case NETDEV_UP: /* new ethernet device -> new BPQ interface */ 576 if (bpq_get_ax25_dev(dev) == NULL) 577 bpq_new_device(dev); 578 break; 579 580 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */ 581 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 582 dev_close(dev); 583 break; 584 585 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */ 586 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 587 bpq_free_device(dev); 588 break; 589 default: 590 break; 591 } 592 593 return NOTIFY_DONE; 594 } 595 596 597 /* ------------------------------------------------------------------------ */ 598 599 /* 600 * Initialize driver. To be called from af_ax25 if not compiled as a 601 * module 602 */ 603 static int __init bpq_init_driver(void) 604 { 605 #ifdef CONFIG_PROC_FS 606 if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) { 607 printk(KERN_ERR 608 "bpq: cannot create /proc/net/bpqether entry.\n"); 609 return -ENOENT; 610 } 611 #endif /* CONFIG_PROC_FS */ 612 613 dev_add_pack(&bpq_packet_type); 614 615 register_netdevice_notifier(&bpq_dev_notifier); 616 617 printk(banner); 618 619 return 0; 620 } 621 622 static void __exit bpq_cleanup_driver(void) 623 { 624 struct bpqdev *bpq; 625 626 dev_remove_pack(&bpq_packet_type); 627 628 unregister_netdevice_notifier(&bpq_dev_notifier); 629 630 proc_net_remove(&init_net, "bpqether"); 631 632 rtnl_lock(); 633 while (!list_empty(&bpq_devices)) { 634 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list); 635 bpq_free_device(bpq->axdev); 636 } 637 rtnl_unlock(); 638 } 639 640 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>"); 641 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet"); 642 MODULE_LICENSE("GPL"); 643 module_init(bpq_init_driver); 644 module_exit(bpq_cleanup_driver); 645