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 netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev) 251 { 252 unsigned char *ptr; 253 struct bpqdev *bpq; 254 int size; 255 256 /* 257 * Just to be *really* sure not to send anything if the interface 258 * is down, the ethernet device may have gone. 259 */ 260 if (!netif_running(dev)) { 261 kfree_skb(skb); 262 return NETDEV_TX_OK; 263 } 264 265 skb_pull(skb, 1); /* Drop KISS byte */ 266 size = skb->len; 267 268 /* 269 * We're about to mess with the skb which may still shared with the 270 * generic networking code so unshare and ensure it's got enough 271 * space for the BPQ headers. 272 */ 273 if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) { 274 if (net_ratelimit()) 275 pr_err("bpqether: out of memory\n"); 276 kfree_skb(skb); 277 278 return NETDEV_TX_OK; 279 } 280 281 ptr = skb_push(skb, 2); /* Make space for length */ 282 283 *ptr++ = (size + 5) % 256; 284 *ptr++ = (size + 5) / 256; 285 286 bpq = netdev_priv(dev); 287 288 if ((dev = bpq_get_ether_dev(dev)) == NULL) { 289 dev->stats.tx_dropped++; 290 kfree_skb(skb); 291 return NETDEV_TX_OK; 292 } 293 294 skb->protocol = ax25_type_trans(skb, dev); 295 skb_reset_network_header(skb); 296 dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0); 297 dev->stats.tx_packets++; 298 dev->stats.tx_bytes+=skb->len; 299 300 dev_queue_xmit(skb); 301 netif_wake_queue(dev); 302 return NETDEV_TX_OK; 303 } 304 305 /* 306 * Set AX.25 callsign 307 */ 308 static int bpq_set_mac_address(struct net_device *dev, void *addr) 309 { 310 struct sockaddr *sa = (struct sockaddr *)addr; 311 312 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 313 314 return 0; 315 } 316 317 /* Ioctl commands 318 * 319 * SIOCSBPQETHOPT reserved for enhancements 320 * SIOCSBPQETHADDR set the destination and accepted 321 * source ethernet address (broadcast 322 * or multicast: accept all) 323 */ 324 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 325 { 326 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data; 327 struct bpqdev *bpq = netdev_priv(dev); 328 struct bpq_req req; 329 330 if (!capable(CAP_NET_ADMIN)) 331 return -EPERM; 332 333 switch (cmd) { 334 case SIOCSBPQETHOPT: 335 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req))) 336 return -EFAULT; 337 switch (req.cmd) { 338 case SIOCGBPQETHPARAM: 339 case SIOCSBPQETHPARAM: 340 default: 341 return -EINVAL; 342 } 343 344 break; 345 346 case SIOCSBPQETHADDR: 347 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN)) 348 return -EFAULT; 349 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN)) 350 return -EFAULT; 351 break; 352 353 default: 354 return -EINVAL; 355 } 356 357 return 0; 358 } 359 360 /* 361 * open/close a device 362 */ 363 static int bpq_open(struct net_device *dev) 364 { 365 netif_start_queue(dev); 366 return 0; 367 } 368 369 static int bpq_close(struct net_device *dev) 370 { 371 netif_stop_queue(dev); 372 return 0; 373 } 374 375 376 /* ------------------------------------------------------------------------ */ 377 378 379 /* 380 * Proc filesystem 381 */ 382 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos) 383 __acquires(RCU) 384 { 385 int i = 1; 386 struct bpqdev *bpqdev; 387 388 rcu_read_lock(); 389 390 if (*pos == 0) 391 return SEQ_START_TOKEN; 392 393 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) { 394 if (i == *pos) 395 return bpqdev; 396 } 397 return NULL; 398 } 399 400 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos) 401 { 402 struct list_head *p; 403 404 ++*pos; 405 406 if (v == SEQ_START_TOKEN) 407 p = rcu_dereference(bpq_devices.next); 408 else 409 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next); 410 411 return (p == &bpq_devices) ? NULL 412 : list_entry(p, struct bpqdev, bpq_list); 413 } 414 415 static void bpq_seq_stop(struct seq_file *seq, void *v) 416 __releases(RCU) 417 { 418 rcu_read_unlock(); 419 } 420 421 422 static int bpq_seq_show(struct seq_file *seq, void *v) 423 { 424 if (v == SEQ_START_TOKEN) 425 seq_puts(seq, 426 "dev ether destination accept from\n"); 427 else { 428 const struct bpqdev *bpqdev = v; 429 430 seq_printf(seq, "%-5s %-10s %pM ", 431 bpqdev->axdev->name, bpqdev->ethdev->name, 432 bpqdev->dest_addr); 433 434 if (is_multicast_ether_addr(bpqdev->acpt_addr)) 435 seq_printf(seq, "*\n"); 436 else 437 seq_printf(seq, "%pM\n", bpqdev->acpt_addr); 438 439 } 440 return 0; 441 } 442 443 static const struct seq_operations bpq_seqops = { 444 .start = bpq_seq_start, 445 .next = bpq_seq_next, 446 .stop = bpq_seq_stop, 447 .show = bpq_seq_show, 448 }; 449 450 static int bpq_info_open(struct inode *inode, struct file *file) 451 { 452 return seq_open(file, &bpq_seqops); 453 } 454 455 static const struct file_operations bpq_info_fops = { 456 .owner = THIS_MODULE, 457 .open = bpq_info_open, 458 .read = seq_read, 459 .llseek = seq_lseek, 460 .release = seq_release, 461 }; 462 463 464 /* ------------------------------------------------------------------------ */ 465 466 static const struct net_device_ops bpq_netdev_ops = { 467 .ndo_open = bpq_open, 468 .ndo_stop = bpq_close, 469 .ndo_start_xmit = bpq_xmit, 470 .ndo_set_mac_address = bpq_set_mac_address, 471 .ndo_do_ioctl = bpq_ioctl, 472 }; 473 474 static void bpq_setup(struct net_device *dev) 475 { 476 dev->netdev_ops = &bpq_netdev_ops; 477 dev->destructor = free_netdev; 478 479 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); 480 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); 481 482 dev->flags = 0; 483 484 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE) 485 dev->header_ops = &ax25_header_ops; 486 #endif 487 488 dev->type = ARPHRD_AX25; 489 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN; 490 dev->mtu = AX25_DEF_PACLEN; 491 dev->addr_len = AX25_ADDR_LEN; 492 493 } 494 495 /* 496 * Setup a new device. 497 */ 498 static int bpq_new_device(struct net_device *edev) 499 { 500 int err; 501 struct net_device *ndev; 502 struct bpqdev *bpq; 503 504 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", 505 bpq_setup); 506 if (!ndev) 507 return -ENOMEM; 508 509 510 bpq = netdev_priv(ndev); 511 dev_hold(edev); 512 bpq->ethdev = edev; 513 bpq->axdev = ndev; 514 515 memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr)); 516 memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr)); 517 518 err = dev_alloc_name(ndev, ndev->name); 519 if (err < 0) 520 goto error; 521 522 err = register_netdevice(ndev); 523 if (err) 524 goto error; 525 bpq_set_lockdep_class(ndev); 526 527 /* List protected by RTNL */ 528 list_add_rcu(&bpq->bpq_list, &bpq_devices); 529 return 0; 530 531 error: 532 dev_put(edev); 533 free_netdev(ndev); 534 return err; 535 536 } 537 538 static void bpq_free_device(struct net_device *ndev) 539 { 540 struct bpqdev *bpq = netdev_priv(ndev); 541 542 dev_put(bpq->ethdev); 543 list_del_rcu(&bpq->bpq_list); 544 545 unregister_netdevice(ndev); 546 } 547 548 /* 549 * Handle device status changes. 550 */ 551 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr) 552 { 553 struct net_device *dev = (struct net_device *)ptr; 554 555 if (dev_net(dev) != &init_net) 556 return NOTIFY_DONE; 557 558 if (!dev_is_ethdev(dev)) 559 return NOTIFY_DONE; 560 561 switch (event) { 562 case NETDEV_UP: /* new ethernet device -> new BPQ interface */ 563 if (bpq_get_ax25_dev(dev) == NULL) 564 bpq_new_device(dev); 565 break; 566 567 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */ 568 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 569 dev_close(dev); 570 break; 571 572 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */ 573 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 574 bpq_free_device(dev); 575 break; 576 default: 577 break; 578 } 579 580 return NOTIFY_DONE; 581 } 582 583 584 /* ------------------------------------------------------------------------ */ 585 586 /* 587 * Initialize driver. To be called from af_ax25 if not compiled as a 588 * module 589 */ 590 static int __init bpq_init_driver(void) 591 { 592 #ifdef CONFIG_PROC_FS 593 if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) { 594 printk(KERN_ERR 595 "bpq: cannot create /proc/net/bpqether entry.\n"); 596 return -ENOENT; 597 } 598 #endif /* CONFIG_PROC_FS */ 599 600 dev_add_pack(&bpq_packet_type); 601 602 register_netdevice_notifier(&bpq_dev_notifier); 603 604 printk(banner); 605 606 return 0; 607 } 608 609 static void __exit bpq_cleanup_driver(void) 610 { 611 struct bpqdev *bpq; 612 613 dev_remove_pack(&bpq_packet_type); 614 615 unregister_netdevice_notifier(&bpq_dev_notifier); 616 617 proc_net_remove(&init_net, "bpqether"); 618 619 rtnl_lock(); 620 while (!list_empty(&bpq_devices)) { 621 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list); 622 bpq_free_device(bpq->axdev); 623 } 624 rtnl_unlock(); 625 } 626 627 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>"); 628 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet"); 629 MODULE_LICENSE("GPL"); 630 module_init(bpq_init_driver); 631 module_exit(bpq_cleanup_driver); 632