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); 638