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 <linux/slab.h> 65 #include <net/ax25.h> 66 #include <linux/inet.h> 67 #include <linux/netdevice.h> 68 #include <linux/etherdevice.h> 69 #include <linux/if_arp.h> 70 #include <linux/skbuff.h> 71 #include <net/sock.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[] __initconst = 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 dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); 171 } 172 173 /* ------------------------------------------------------------------------ */ 174 175 176 /* 177 * Receive an AX.25 frame via an ethernet interface. 178 */ 179 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) 180 { 181 int len; 182 char * ptr; 183 struct ethhdr *eth; 184 struct bpqdev *bpq; 185 186 if (!net_eq(dev_net(dev), &init_net)) 187 goto drop; 188 189 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 190 return NET_RX_DROP; 191 192 if (!pskb_may_pull(skb, sizeof(struct ethhdr))) 193 goto drop; 194 195 rcu_read_lock(); 196 dev = bpq_get_ax25_dev(dev); 197 198 if (dev == NULL || !netif_running(dev)) 199 goto drop_unlock; 200 201 /* 202 * if we want to accept frames from just one ethernet device 203 * we check the source address of the sender. 204 */ 205 206 bpq = netdev_priv(dev); 207 208 eth = eth_hdr(skb); 209 210 if (!(bpq->acpt_addr[0] & 0x01) && 211 !ether_addr_equal(eth->h_source, bpq->acpt_addr)) 212 goto drop_unlock; 213 214 if (skb_cow(skb, sizeof(struct ethhdr))) 215 goto drop_unlock; 216 217 len = skb->data[0] + skb->data[1] * 256 - 5; 218 219 skb_pull(skb, 2); /* Remove the length bytes */ 220 skb_trim(skb, len); /* Set the length of the data */ 221 222 dev->stats.rx_packets++; 223 dev->stats.rx_bytes += len; 224 225 ptr = skb_push(skb, 1); 226 *ptr = 0; 227 228 skb->protocol = ax25_type_trans(skb, dev); 229 netif_rx(skb); 230 unlock: 231 232 rcu_read_unlock(); 233 234 return 0; 235 drop_unlock: 236 kfree_skb(skb); 237 goto unlock; 238 239 drop: 240 kfree_skb(skb); 241 return 0; 242 } 243 244 /* 245 * Send an AX.25 frame via an ethernet interface 246 */ 247 static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev) 248 { 249 unsigned char *ptr; 250 struct bpqdev *bpq; 251 struct net_device *orig_dev; 252 int size; 253 254 /* 255 * Just to be *really* sure not to send anything if the interface 256 * is down, the ethernet device may have gone. 257 */ 258 if (!netif_running(dev)) { 259 kfree_skb(skb); 260 return NETDEV_TX_OK; 261 } 262 263 skb_pull(skb, 1); /* Drop KISS byte */ 264 size = skb->len; 265 266 /* 267 * We're about to mess with the skb which may still shared with the 268 * generic networking code so unshare and ensure it's got enough 269 * space for the BPQ headers. 270 */ 271 if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) { 272 if (net_ratelimit()) 273 pr_err("bpqether: out of memory\n"); 274 kfree_skb(skb); 275 276 return NETDEV_TX_OK; 277 } 278 279 ptr = skb_push(skb, 2); /* Make space for length */ 280 281 *ptr++ = (size + 5) % 256; 282 *ptr++ = (size + 5) / 256; 283 284 bpq = netdev_priv(dev); 285 286 orig_dev = dev; 287 if ((dev = bpq_get_ether_dev(dev)) == NULL) { 288 orig_dev->stats.tx_dropped++; 289 kfree_skb(skb); 290 return NETDEV_TX_OK; 291 } 292 293 skb->protocol = ax25_type_trans(skb, dev); 294 skb_reset_network_header(skb); 295 dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0); 296 dev->stats.tx_packets++; 297 dev->stats.tx_bytes+=skb->len; 298 299 dev_queue_xmit(skb); 300 netif_wake_queue(dev); 301 return NETDEV_TX_OK; 302 } 303 304 /* 305 * Set AX.25 callsign 306 */ 307 static int bpq_set_mac_address(struct net_device *dev, void *addr) 308 { 309 struct sockaddr *sa = (struct sockaddr *)addr; 310 311 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 312 313 return 0; 314 } 315 316 /* Ioctl commands 317 * 318 * SIOCSBPQETHOPT reserved for enhancements 319 * SIOCSBPQETHADDR set the destination and accepted 320 * source ethernet address (broadcast 321 * or multicast: accept all) 322 */ 323 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 324 { 325 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data; 326 struct bpqdev *bpq = netdev_priv(dev); 327 struct bpq_req req; 328 329 if (!capable(CAP_NET_ADMIN)) 330 return -EPERM; 331 332 switch (cmd) { 333 case SIOCSBPQETHOPT: 334 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req))) 335 return -EFAULT; 336 switch (req.cmd) { 337 case SIOCGBPQETHPARAM: 338 case SIOCSBPQETHPARAM: 339 default: 340 return -EINVAL; 341 } 342 343 break; 344 345 case SIOCSBPQETHADDR: 346 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN)) 347 return -EFAULT; 348 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN)) 349 return -EFAULT; 350 break; 351 352 default: 353 return -EINVAL; 354 } 355 356 return 0; 357 } 358 359 /* 360 * open/close a device 361 */ 362 static int bpq_open(struct net_device *dev) 363 { 364 netif_start_queue(dev); 365 return 0; 366 } 367 368 static int bpq_close(struct net_device *dev) 369 { 370 netif_stop_queue(dev); 371 return 0; 372 } 373 374 375 /* ------------------------------------------------------------------------ */ 376 377 378 /* 379 * Proc filesystem 380 */ 381 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos) 382 __acquires(RCU) 383 { 384 int i = 1; 385 struct bpqdev *bpqdev; 386 387 rcu_read_lock(); 388 389 if (*pos == 0) 390 return SEQ_START_TOKEN; 391 392 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) { 393 if (i == *pos) 394 return bpqdev; 395 } 396 return NULL; 397 } 398 399 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos) 400 { 401 struct list_head *p; 402 struct bpqdev *bpqdev = v; 403 404 ++*pos; 405 406 if (v == SEQ_START_TOKEN) 407 p = rcu_dereference(list_next_rcu(&bpq_devices)); 408 else 409 p = rcu_dereference(list_next_rcu(&bpqdev->bpq_list)); 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", NET_NAME_UNKNOWN, 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 = register_netdevice(ndev); 519 if (err) 520 goto error; 521 bpq_set_lockdep_class(ndev); 522 523 /* List protected by RTNL */ 524 list_add_rcu(&bpq->bpq_list, &bpq_devices); 525 return 0; 526 527 error: 528 dev_put(edev); 529 free_netdev(ndev); 530 return err; 531 532 } 533 534 static void bpq_free_device(struct net_device *ndev) 535 { 536 struct bpqdev *bpq = netdev_priv(ndev); 537 538 dev_put(bpq->ethdev); 539 list_del_rcu(&bpq->bpq_list); 540 541 unregister_netdevice(ndev); 542 } 543 544 /* 545 * Handle device status changes. 546 */ 547 static int bpq_device_event(struct notifier_block *this, 548 unsigned long event, void *ptr) 549 { 550 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 551 552 if (!net_eq(dev_net(dev), &init_net)) 553 return NOTIFY_DONE; 554 555 if (!dev_is_ethdev(dev)) 556 return NOTIFY_DONE; 557 558 switch (event) { 559 case NETDEV_UP: /* new ethernet device -> new BPQ interface */ 560 if (bpq_get_ax25_dev(dev) == NULL) 561 bpq_new_device(dev); 562 break; 563 564 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */ 565 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 566 dev_close(dev); 567 break; 568 569 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */ 570 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 571 bpq_free_device(dev); 572 break; 573 default: 574 break; 575 } 576 577 return NOTIFY_DONE; 578 } 579 580 581 /* ------------------------------------------------------------------------ */ 582 583 /* 584 * Initialize driver. To be called from af_ax25 if not compiled as a 585 * module 586 */ 587 static int __init bpq_init_driver(void) 588 { 589 #ifdef CONFIG_PROC_FS 590 if (!proc_create("bpqether", S_IRUGO, init_net.proc_net, 591 &bpq_info_fops)) { 592 printk(KERN_ERR 593 "bpq: cannot create /proc/net/bpqether entry.\n"); 594 return -ENOENT; 595 } 596 #endif /* CONFIG_PROC_FS */ 597 598 dev_add_pack(&bpq_packet_type); 599 600 register_netdevice_notifier(&bpq_dev_notifier); 601 602 printk(banner); 603 604 return 0; 605 } 606 607 static void __exit bpq_cleanup_driver(void) 608 { 609 struct bpqdev *bpq; 610 611 dev_remove_pack(&bpq_packet_type); 612 613 unregister_netdevice_notifier(&bpq_dev_notifier); 614 615 remove_proc_entry("bpqether", init_net.proc_net); 616 617 rtnl_lock(); 618 while (!list_empty(&bpq_devices)) { 619 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list); 620 bpq_free_device(bpq->axdev); 621 } 622 rtnl_unlock(); 623 } 624 625 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>"); 626 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet"); 627 MODULE_LICENSE("GPL"); 628 module_init(bpq_init_driver); 629 module_exit(bpq_cleanup_driver); 630