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_net(dev) != &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->header_ops = &ax25_header_ops; 487 #endif 488 489 dev->type = ARPHRD_AX25; 490 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN; 491 dev->mtu = AX25_DEF_PACLEN; 492 dev->addr_len = AX25_ADDR_LEN; 493 494 } 495 496 /* 497 * Setup a new device. 498 */ 499 static int bpq_new_device(struct net_device *edev) 500 { 501 int err; 502 struct net_device *ndev; 503 struct bpqdev *bpq; 504 505 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d", 506 bpq_setup); 507 if (!ndev) 508 return -ENOMEM; 509 510 511 bpq = netdev_priv(ndev); 512 dev_hold(edev); 513 bpq->ethdev = edev; 514 bpq->axdev = ndev; 515 516 memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr)); 517 memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr)); 518 519 err = dev_alloc_name(ndev, ndev->name); 520 if (err < 0) 521 goto error; 522 523 err = register_netdevice(ndev); 524 if (err) 525 goto error; 526 lockdep_set_class(&ndev->_xmit_lock, &bpq_netdev_xmit_lock_key); 527 528 /* List protected by RTNL */ 529 list_add_rcu(&bpq->bpq_list, &bpq_devices); 530 return 0; 531 532 error: 533 dev_put(edev); 534 free_netdev(ndev); 535 return err; 536 537 } 538 539 static void bpq_free_device(struct net_device *ndev) 540 { 541 struct bpqdev *bpq = netdev_priv(ndev); 542 543 dev_put(bpq->ethdev); 544 list_del_rcu(&bpq->bpq_list); 545 546 unregister_netdevice(ndev); 547 } 548 549 /* 550 * Handle device status changes. 551 */ 552 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr) 553 { 554 struct net_device *dev = (struct net_device *)ptr; 555 556 if (dev_net(dev) != &init_net) 557 return NOTIFY_DONE; 558 559 if (!dev_is_ethdev(dev)) 560 return NOTIFY_DONE; 561 562 switch (event) { 563 case NETDEV_UP: /* new ethernet device -> new BPQ interface */ 564 if (bpq_get_ax25_dev(dev) == NULL) 565 bpq_new_device(dev); 566 break; 567 568 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */ 569 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 570 dev_close(dev); 571 break; 572 573 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */ 574 if ((dev = bpq_get_ax25_dev(dev)) != NULL) 575 bpq_free_device(dev); 576 break; 577 default: 578 break; 579 } 580 581 return NOTIFY_DONE; 582 } 583 584 585 /* ------------------------------------------------------------------------ */ 586 587 /* 588 * Initialize driver. To be called from af_ax25 if not compiled as a 589 * module 590 */ 591 static int __init bpq_init_driver(void) 592 { 593 #ifdef CONFIG_PROC_FS 594 if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) { 595 printk(KERN_ERR 596 "bpq: cannot create /proc/net/bpqether entry.\n"); 597 return -ENOENT; 598 } 599 #endif /* CONFIG_PROC_FS */ 600 601 dev_add_pack(&bpq_packet_type); 602 603 register_netdevice_notifier(&bpq_dev_notifier); 604 605 printk(banner); 606 607 return 0; 608 } 609 610 static void __exit bpq_cleanup_driver(void) 611 { 612 struct bpqdev *bpq; 613 614 dev_remove_pack(&bpq_packet_type); 615 616 unregister_netdevice_notifier(&bpq_dev_notifier); 617 618 proc_net_remove(&init_net, "bpqether"); 619 620 rtnl_lock(); 621 while (!list_empty(&bpq_devices)) { 622 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list); 623 bpq_free_device(bpq->axdev); 624 } 625 rtnl_unlock(); 626 } 627 628 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>"); 629 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet"); 630 MODULE_LICENSE("GPL"); 631 module_init(bpq_init_driver); 632 module_exit(bpq_cleanup_driver); 633