1 /* 2 * 6pack.c This module implements the 6pack protocol for kernel-based 3 * devices like TTY. It interfaces between a raw TTY and the 4 * kernel's AX.25 protocol layers. 5 * 6 * Authors: Andreas Könsgen <ajk@comnets.uni-bremen.de> 7 * Ralf Baechle DL5RB <ralf@linux-mips.org> 8 * 9 * Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by 10 * 11 * Laurence Culhane, <loz@holmes.demon.co.uk> 12 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> 13 */ 14 15 #include <linux/module.h> 16 #include <asm/uaccess.h> 17 #include <linux/bitops.h> 18 #include <linux/string.h> 19 #include <linux/mm.h> 20 #include <linux/interrupt.h> 21 #include <linux/in.h> 22 #include <linux/tty.h> 23 #include <linux/errno.h> 24 #include <linux/netdevice.h> 25 #include <linux/timer.h> 26 #include <linux/slab.h> 27 #include <net/ax25.h> 28 #include <linux/etherdevice.h> 29 #include <linux/skbuff.h> 30 #include <linux/rtnetlink.h> 31 #include <linux/spinlock.h> 32 #include <linux/if_arp.h> 33 #include <linux/init.h> 34 #include <linux/ip.h> 35 #include <linux/tcp.h> 36 #include <linux/semaphore.h> 37 #include <linux/compat.h> 38 #include <linux/atomic.h> 39 40 #define SIXPACK_VERSION "Revision: 0.3.0" 41 42 /* sixpack priority commands */ 43 #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */ 44 #define SIXP_TX_URUN 0x48 /* transmit overrun */ 45 #define SIXP_RX_ORUN 0x50 /* receive overrun */ 46 #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */ 47 48 #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */ 49 50 /* masks to get certain bits out of the status bytes sent by the TNC */ 51 52 #define SIXP_CMD_MASK 0xC0 53 #define SIXP_CHN_MASK 0x07 54 #define SIXP_PRIO_CMD_MASK 0x80 55 #define SIXP_STD_CMD_MASK 0x40 56 #define SIXP_PRIO_DATA_MASK 0x38 57 #define SIXP_TX_MASK 0x20 58 #define SIXP_RX_MASK 0x10 59 #define SIXP_RX_DCD_MASK 0x18 60 #define SIXP_LEDS_ON 0x78 61 #define SIXP_LEDS_OFF 0x60 62 #define SIXP_CON 0x08 63 #define SIXP_STA 0x10 64 65 #define SIXP_FOUND_TNC 0xe9 66 #define SIXP_CON_ON 0x68 67 #define SIXP_DCD_MASK 0x08 68 #define SIXP_DAMA_OFF 0 69 70 /* default level 2 parameters */ 71 #define SIXP_TXDELAY (HZ/4) /* in 1 s */ 72 #define SIXP_PERSIST 50 /* in 256ths */ 73 #define SIXP_SLOTTIME (HZ/10) /* in 1 s */ 74 #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */ 75 #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */ 76 77 /* 6pack configuration. */ 78 #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */ 79 #define SIXP_MTU 256 /* Default MTU */ 80 81 enum sixpack_flags { 82 SIXPF_ERROR, /* Parity, etc. error */ 83 }; 84 85 struct sixpack { 86 /* Various fields. */ 87 struct tty_struct *tty; /* ptr to TTY structure */ 88 struct net_device *dev; /* easy for intr handling */ 89 90 /* These are pointers to the malloc()ed frame buffers. */ 91 unsigned char *rbuff; /* receiver buffer */ 92 int rcount; /* received chars counter */ 93 unsigned char *xbuff; /* transmitter buffer */ 94 unsigned char *xhead; /* next byte to XMIT */ 95 int xleft; /* bytes left in XMIT queue */ 96 97 unsigned char raw_buf[4]; 98 unsigned char cooked_buf[400]; 99 100 unsigned int rx_count; 101 unsigned int rx_count_cooked; 102 103 int mtu; /* Our mtu (to spot changes!) */ 104 int buffsize; /* Max buffers sizes */ 105 106 unsigned long flags; /* Flag values/ mode etc */ 107 unsigned char mode; /* 6pack mode */ 108 109 /* 6pack stuff */ 110 unsigned char tx_delay; 111 unsigned char persistence; 112 unsigned char slottime; 113 unsigned char duplex; 114 unsigned char led_state; 115 unsigned char status; 116 unsigned char status1; 117 unsigned char status2; 118 unsigned char tx_enable; 119 unsigned char tnc_state; 120 121 struct timer_list tx_t; 122 struct timer_list resync_t; 123 atomic_t refcnt; 124 struct semaphore dead_sem; 125 spinlock_t lock; 126 }; 127 128 #define AX25_6PACK_HEADER_LEN 0 129 130 static void sixpack_decode(struct sixpack *, unsigned char[], int); 131 static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); 132 133 /* 134 * Perform the persistence/slottime algorithm for CSMA access. If the 135 * persistence check was successful, write the data to the serial driver. 136 * Note that in case of DAMA operation, the data is not sent here. 137 */ 138 139 static void sp_xmit_on_air(unsigned long channel) 140 { 141 struct sixpack *sp = (struct sixpack *) channel; 142 int actual, when = sp->slottime; 143 static unsigned char random; 144 145 random = random * 17 + 41; 146 147 if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) { 148 sp->led_state = 0x70; 149 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 150 sp->tx_enable = 1; 151 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); 152 sp->xleft -= actual; 153 sp->xhead += actual; 154 sp->led_state = 0x60; 155 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 156 sp->status2 = 0; 157 } else 158 mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); 159 } 160 161 /* ----> 6pack timer interrupt handler and friends. <---- */ 162 163 /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ 164 static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) 165 { 166 unsigned char *msg, *p = icp; 167 int actual, count; 168 169 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ 170 msg = "oversized transmit packet!"; 171 goto out_drop; 172 } 173 174 if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ 175 msg = "oversized transmit packet!"; 176 goto out_drop; 177 } 178 179 if (p[0] > 5) { 180 msg = "invalid KISS command"; 181 goto out_drop; 182 } 183 184 if ((p[0] != 0) && (len > 2)) { 185 msg = "KISS control packet too long"; 186 goto out_drop; 187 } 188 189 if ((p[0] == 0) && (len < 15)) { 190 msg = "bad AX.25 packet to transmit"; 191 goto out_drop; 192 } 193 194 count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay); 195 set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); 196 197 switch (p[0]) { 198 case 1: sp->tx_delay = p[1]; 199 return; 200 case 2: sp->persistence = p[1]; 201 return; 202 case 3: sp->slottime = p[1]; 203 return; 204 case 4: /* ignored */ 205 return; 206 case 5: sp->duplex = p[1]; 207 return; 208 } 209 210 if (p[0] != 0) 211 return; 212 213 /* 214 * In case of fullduplex or DAMA operation, we don't take care about the 215 * state of the DCD or of any timers, as the determination of the 216 * correct time to send is the job of the AX.25 layer. We send 217 * immediately after data has arrived. 218 */ 219 if (sp->duplex == 1) { 220 sp->led_state = 0x70; 221 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 222 sp->tx_enable = 1; 223 actual = sp->tty->ops->write(sp->tty, sp->xbuff, count); 224 sp->xleft = count - actual; 225 sp->xhead = sp->xbuff + actual; 226 sp->led_state = 0x60; 227 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 228 } else { 229 sp->xleft = count; 230 sp->xhead = sp->xbuff; 231 sp->status2 = count; 232 sp_xmit_on_air((unsigned long)sp); 233 } 234 235 return; 236 237 out_drop: 238 sp->dev->stats.tx_dropped++; 239 netif_start_queue(sp->dev); 240 if (net_ratelimit()) 241 printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg); 242 } 243 244 /* Encapsulate an IP datagram and kick it into a TTY queue. */ 245 246 static netdev_tx_t sp_xmit(struct sk_buff *skb, struct net_device *dev) 247 { 248 struct sixpack *sp = netdev_priv(dev); 249 250 if (skb->protocol == htons(ETH_P_IP)) 251 return ax25_ip_xmit(skb); 252 253 spin_lock_bh(&sp->lock); 254 /* We were not busy, so we are now... :-) */ 255 netif_stop_queue(dev); 256 dev->stats.tx_bytes += skb->len; 257 sp_encaps(sp, skb->data, skb->len); 258 spin_unlock_bh(&sp->lock); 259 260 dev_kfree_skb(skb); 261 262 return NETDEV_TX_OK; 263 } 264 265 static int sp_open_dev(struct net_device *dev) 266 { 267 struct sixpack *sp = netdev_priv(dev); 268 269 if (sp->tty == NULL) 270 return -ENODEV; 271 return 0; 272 } 273 274 /* Close the low-level part of the 6pack channel. */ 275 static int sp_close(struct net_device *dev) 276 { 277 struct sixpack *sp = netdev_priv(dev); 278 279 spin_lock_bh(&sp->lock); 280 if (sp->tty) { 281 /* TTY discipline is running. */ 282 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); 283 } 284 netif_stop_queue(dev); 285 spin_unlock_bh(&sp->lock); 286 287 return 0; 288 } 289 290 static int sp_set_mac_address(struct net_device *dev, void *addr) 291 { 292 struct sockaddr_ax25 *sa = addr; 293 294 netif_tx_lock_bh(dev); 295 netif_addr_lock(dev); 296 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); 297 netif_addr_unlock(dev); 298 netif_tx_unlock_bh(dev); 299 300 return 0; 301 } 302 303 static const struct net_device_ops sp_netdev_ops = { 304 .ndo_open = sp_open_dev, 305 .ndo_stop = sp_close, 306 .ndo_start_xmit = sp_xmit, 307 .ndo_set_mac_address = sp_set_mac_address, 308 }; 309 310 static void sp_setup(struct net_device *dev) 311 { 312 /* Finish setting up the DEVICE info. */ 313 dev->netdev_ops = &sp_netdev_ops; 314 dev->destructor = free_netdev; 315 dev->mtu = SIXP_MTU; 316 dev->hard_header_len = AX25_MAX_HEADER_LEN; 317 dev->header_ops = &ax25_header_ops; 318 319 dev->addr_len = AX25_ADDR_LEN; 320 dev->type = ARPHRD_AX25; 321 dev->tx_queue_len = 10; 322 323 /* Only activated in AX.25 mode */ 324 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); 325 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); 326 327 dev->flags = 0; 328 } 329 330 /* Send one completely decapsulated IP datagram to the IP layer. */ 331 332 /* 333 * This is the routine that sends the received data to the kernel AX.25. 334 * 'cmd' is the KISS command. For AX.25 data, it is zero. 335 */ 336 337 static void sp_bump(struct sixpack *sp, char cmd) 338 { 339 struct sk_buff *skb; 340 int count; 341 unsigned char *ptr; 342 343 count = sp->rcount + 1; 344 345 sp->dev->stats.rx_bytes += count; 346 347 if ((skb = dev_alloc_skb(count)) == NULL) 348 goto out_mem; 349 350 ptr = skb_put(skb, count); 351 *ptr++ = cmd; /* KISS command */ 352 353 memcpy(ptr, sp->cooked_buf + 1, count); 354 skb->protocol = ax25_type_trans(skb, sp->dev); 355 netif_rx(skb); 356 sp->dev->stats.rx_packets++; 357 358 return; 359 360 out_mem: 361 sp->dev->stats.rx_dropped++; 362 } 363 364 365 /* ----------------------------------------------------------------------- */ 366 367 /* 368 * We have a potential race on dereferencing tty->disc_data, because the tty 369 * layer provides no locking at all - thus one cpu could be running 370 * sixpack_receive_buf while another calls sixpack_close, which zeroes 371 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The 372 * best way to fix this is to use a rwlock in the tty struct, but for now we 373 * use a single global rwlock for all ttys in ppp line discipline. 374 */ 375 static DEFINE_RWLOCK(disc_data_lock); 376 377 static struct sixpack *sp_get(struct tty_struct *tty) 378 { 379 struct sixpack *sp; 380 381 read_lock(&disc_data_lock); 382 sp = tty->disc_data; 383 if (sp) 384 atomic_inc(&sp->refcnt); 385 read_unlock(&disc_data_lock); 386 387 return sp; 388 } 389 390 static void sp_put(struct sixpack *sp) 391 { 392 if (atomic_dec_and_test(&sp->refcnt)) 393 up(&sp->dead_sem); 394 } 395 396 /* 397 * Called by the TTY driver when there's room for more data. If we have 398 * more packets to send, we send them here. 399 */ 400 static void sixpack_write_wakeup(struct tty_struct *tty) 401 { 402 struct sixpack *sp = sp_get(tty); 403 int actual; 404 405 if (!sp) 406 return; 407 if (sp->xleft <= 0) { 408 /* Now serial buffer is almost free & we can start 409 * transmission of another packet */ 410 sp->dev->stats.tx_packets++; 411 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 412 sp->tx_enable = 0; 413 netif_wake_queue(sp->dev); 414 goto out; 415 } 416 417 if (sp->tx_enable) { 418 actual = tty->ops->write(tty, sp->xhead, sp->xleft); 419 sp->xleft -= actual; 420 sp->xhead += actual; 421 } 422 423 out: 424 sp_put(sp); 425 } 426 427 /* ----------------------------------------------------------------------- */ 428 429 /* 430 * Handle the 'receiver data ready' interrupt. 431 * This function is called by the 'tty_io' module in the kernel when 432 * a block of 6pack data has been received, which can now be decapsulated 433 * and sent on to some IP layer for further processing. 434 */ 435 static void sixpack_receive_buf(struct tty_struct *tty, 436 const unsigned char *cp, char *fp, int count) 437 { 438 struct sixpack *sp; 439 unsigned char buf[512]; 440 int count1; 441 442 if (!count) 443 return; 444 445 sp = sp_get(tty); 446 if (!sp) 447 return; 448 449 memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); 450 451 /* Read the characters out of the buffer */ 452 453 count1 = count; 454 while (count) { 455 count--; 456 if (fp && *fp++) { 457 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) 458 sp->dev->stats.rx_errors++; 459 continue; 460 } 461 } 462 sixpack_decode(sp, buf, count1); 463 464 sp_put(sp); 465 tty_unthrottle(tty); 466 } 467 468 /* 469 * Try to resync the TNC. Called by the resync timer defined in 470 * decode_prio_command 471 */ 472 473 #define TNC_UNINITIALIZED 0 474 #define TNC_UNSYNC_STARTUP 1 475 #define TNC_UNSYNCED 2 476 #define TNC_IN_SYNC 3 477 478 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) 479 { 480 char *msg; 481 482 switch (new_tnc_state) { 483 default: /* gcc oh piece-o-crap ... */ 484 case TNC_UNSYNC_STARTUP: 485 msg = "Synchronizing with TNC"; 486 break; 487 case TNC_UNSYNCED: 488 msg = "Lost synchronization with TNC\n"; 489 break; 490 case TNC_IN_SYNC: 491 msg = "Found TNC"; 492 break; 493 } 494 495 sp->tnc_state = new_tnc_state; 496 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); 497 } 498 499 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) 500 { 501 int old_tnc_state = sp->tnc_state; 502 503 if (old_tnc_state != new_tnc_state) 504 __tnc_set_sync_state(sp, new_tnc_state); 505 } 506 507 static void resync_tnc(unsigned long channel) 508 { 509 struct sixpack *sp = (struct sixpack *) channel; 510 static char resync_cmd = 0xe8; 511 512 /* clear any data that might have been received */ 513 514 sp->rx_count = 0; 515 sp->rx_count_cooked = 0; 516 517 /* reset state machine */ 518 519 sp->status = 1; 520 sp->status1 = 1; 521 sp->status2 = 0; 522 523 /* resync the TNC */ 524 525 sp->led_state = 0x60; 526 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 527 sp->tty->ops->write(sp->tty, &resync_cmd, 1); 528 529 530 /* Start resync timer again -- the TNC might be still absent */ 531 532 del_timer(&sp->resync_t); 533 sp->resync_t.data = (unsigned long) sp; 534 sp->resync_t.function = resync_tnc; 535 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; 536 add_timer(&sp->resync_t); 537 } 538 539 static inline int tnc_init(struct sixpack *sp) 540 { 541 unsigned char inbyte = 0xe8; 542 543 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); 544 545 sp->tty->ops->write(sp->tty, &inbyte, 1); 546 547 del_timer(&sp->resync_t); 548 sp->resync_t.data = (unsigned long) sp; 549 sp->resync_t.function = resync_tnc; 550 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; 551 add_timer(&sp->resync_t); 552 553 return 0; 554 } 555 556 /* 557 * Open the high-level part of the 6pack channel. 558 * This function is called by the TTY module when the 559 * 6pack line discipline is called for. Because we are 560 * sure the tty line exists, we only have to link it to 561 * a free 6pcack channel... 562 */ 563 static int sixpack_open(struct tty_struct *tty) 564 { 565 char *rbuff = NULL, *xbuff = NULL; 566 struct net_device *dev; 567 struct sixpack *sp; 568 unsigned long len; 569 int err = 0; 570 571 if (!capable(CAP_NET_ADMIN)) 572 return -EPERM; 573 if (tty->ops->write == NULL) 574 return -EOPNOTSUPP; 575 576 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN, 577 sp_setup); 578 if (!dev) { 579 err = -ENOMEM; 580 goto out; 581 } 582 583 sp = netdev_priv(dev); 584 sp->dev = dev; 585 586 spin_lock_init(&sp->lock); 587 atomic_set(&sp->refcnt, 1); 588 sema_init(&sp->dead_sem, 0); 589 590 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ 591 592 len = dev->mtu * 2; 593 594 rbuff = kmalloc(len + 4, GFP_KERNEL); 595 xbuff = kmalloc(len + 4, GFP_KERNEL); 596 597 if (rbuff == NULL || xbuff == NULL) { 598 err = -ENOBUFS; 599 goto out_free; 600 } 601 602 spin_lock_bh(&sp->lock); 603 604 sp->tty = tty; 605 606 sp->rbuff = rbuff; 607 sp->xbuff = xbuff; 608 609 sp->mtu = AX25_MTU + 73; 610 sp->buffsize = len; 611 sp->rcount = 0; 612 sp->rx_count = 0; 613 sp->rx_count_cooked = 0; 614 sp->xleft = 0; 615 616 sp->flags = 0; /* Clear ESCAPE & ERROR flags */ 617 618 sp->duplex = 0; 619 sp->tx_delay = SIXP_TXDELAY; 620 sp->persistence = SIXP_PERSIST; 621 sp->slottime = SIXP_SLOTTIME; 622 sp->led_state = 0x60; 623 sp->status = 1; 624 sp->status1 = 1; 625 sp->status2 = 0; 626 sp->tx_enable = 0; 627 628 netif_start_queue(dev); 629 630 init_timer(&sp->tx_t); 631 sp->tx_t.function = sp_xmit_on_air; 632 sp->tx_t.data = (unsigned long) sp; 633 634 init_timer(&sp->resync_t); 635 636 spin_unlock_bh(&sp->lock); 637 638 /* Done. We have linked the TTY line to a channel. */ 639 tty->disc_data = sp; 640 tty->receive_room = 65536; 641 642 /* Now we're ready to register. */ 643 err = register_netdev(dev); 644 if (err) 645 goto out_free; 646 647 tnc_init(sp); 648 649 return 0; 650 651 out_free: 652 kfree(xbuff); 653 kfree(rbuff); 654 655 free_netdev(dev); 656 657 out: 658 return err; 659 } 660 661 662 /* 663 * Close down a 6pack channel. 664 * This means flushing out any pending queues, and then restoring the 665 * TTY line discipline to what it was before it got hooked to 6pack 666 * (which usually is TTY again). 667 */ 668 static void sixpack_close(struct tty_struct *tty) 669 { 670 struct sixpack *sp; 671 672 write_lock_bh(&disc_data_lock); 673 sp = tty->disc_data; 674 tty->disc_data = NULL; 675 write_unlock_bh(&disc_data_lock); 676 if (!sp) 677 return; 678 679 /* 680 * We have now ensured that nobody can start using ap from now on, but 681 * we have to wait for all existing users to finish. 682 */ 683 if (!atomic_dec_and_test(&sp->refcnt)) 684 down(&sp->dead_sem); 685 686 /* We must stop the queue to avoid potentially scribbling 687 * on the free buffers. The sp->dead_sem is not sufficient 688 * to protect us from sp->xbuff access. 689 */ 690 netif_stop_queue(sp->dev); 691 692 del_timer_sync(&sp->tx_t); 693 del_timer_sync(&sp->resync_t); 694 695 /* Free all 6pack frame buffers. */ 696 kfree(sp->rbuff); 697 kfree(sp->xbuff); 698 699 unregister_netdev(sp->dev); 700 } 701 702 /* Perform I/O control on an active 6pack channel. */ 703 static int sixpack_ioctl(struct tty_struct *tty, struct file *file, 704 unsigned int cmd, unsigned long arg) 705 { 706 struct sixpack *sp = sp_get(tty); 707 struct net_device *dev; 708 unsigned int tmp, err; 709 710 if (!sp) 711 return -ENXIO; 712 dev = sp->dev; 713 714 switch(cmd) { 715 case SIOCGIFNAME: 716 err = copy_to_user((void __user *) arg, dev->name, 717 strlen(dev->name) + 1) ? -EFAULT : 0; 718 break; 719 720 case SIOCGIFENCAP: 721 err = put_user(0, (int __user *) arg); 722 break; 723 724 case SIOCSIFENCAP: 725 if (get_user(tmp, (int __user *) arg)) { 726 err = -EFAULT; 727 break; 728 } 729 730 sp->mode = tmp; 731 dev->addr_len = AX25_ADDR_LEN; 732 dev->hard_header_len = AX25_KISS_HEADER_LEN + 733 AX25_MAX_HEADER_LEN + 3; 734 dev->type = ARPHRD_AX25; 735 736 err = 0; 737 break; 738 739 case SIOCSIFHWADDR: { 740 char addr[AX25_ADDR_LEN]; 741 742 if (copy_from_user(&addr, 743 (void __user *) arg, AX25_ADDR_LEN)) { 744 err = -EFAULT; 745 break; 746 } 747 748 netif_tx_lock_bh(dev); 749 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); 750 netif_tx_unlock_bh(dev); 751 752 err = 0; 753 break; 754 } 755 756 default: 757 err = tty_mode_ioctl(tty, file, cmd, arg); 758 } 759 760 sp_put(sp); 761 762 return err; 763 } 764 765 #ifdef CONFIG_COMPAT 766 static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file, 767 unsigned int cmd, unsigned long arg) 768 { 769 switch (cmd) { 770 case SIOCGIFNAME: 771 case SIOCGIFENCAP: 772 case SIOCSIFENCAP: 773 case SIOCSIFHWADDR: 774 return sixpack_ioctl(tty, file, cmd, 775 (unsigned long)compat_ptr(arg)); 776 } 777 778 return -ENOIOCTLCMD; 779 } 780 #endif 781 782 static struct tty_ldisc_ops sp_ldisc = { 783 .owner = THIS_MODULE, 784 .magic = TTY_LDISC_MAGIC, 785 .name = "6pack", 786 .open = sixpack_open, 787 .close = sixpack_close, 788 .ioctl = sixpack_ioctl, 789 #ifdef CONFIG_COMPAT 790 .compat_ioctl = sixpack_compat_ioctl, 791 #endif 792 .receive_buf = sixpack_receive_buf, 793 .write_wakeup = sixpack_write_wakeup, 794 }; 795 796 /* Initialize 6pack control device -- register 6pack line discipline */ 797 798 static const char msg_banner[] __initconst = KERN_INFO \ 799 "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; 800 static const char msg_regfail[] __initconst = KERN_ERR \ 801 "6pack: can't register line discipline (err = %d)\n"; 802 803 static int __init sixpack_init_driver(void) 804 { 805 int status; 806 807 printk(msg_banner); 808 809 /* Register the provided line protocol discipline */ 810 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) 811 printk(msg_regfail, status); 812 813 return status; 814 } 815 816 static const char msg_unregfail[] = KERN_ERR \ 817 "6pack: can't unregister line discipline (err = %d)\n"; 818 819 static void __exit sixpack_exit_driver(void) 820 { 821 int ret; 822 823 if ((ret = tty_unregister_ldisc(N_6PACK))) 824 printk(msg_unregfail, ret); 825 } 826 827 /* encode an AX.25 packet into 6pack */ 828 829 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, 830 int length, unsigned char tx_delay) 831 { 832 int count = 0; 833 unsigned char checksum = 0, buf[400]; 834 int raw_count = 0; 835 836 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; 837 tx_buf_raw[raw_count++] = SIXP_SEOF; 838 839 buf[0] = tx_delay; 840 for (count = 1; count < length; count++) 841 buf[count] = tx_buf[count]; 842 843 for (count = 0; count < length; count++) 844 checksum += buf[count]; 845 buf[length] = (unsigned char) 0xff - checksum; 846 847 for (count = 0; count <= length; count++) { 848 if ((count % 3) == 0) { 849 tx_buf_raw[raw_count++] = (buf[count] & 0x3f); 850 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); 851 } else if ((count % 3) == 1) { 852 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); 853 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); 854 } else { 855 tx_buf_raw[raw_count++] |= (buf[count] & 0x03); 856 tx_buf_raw[raw_count++] = (buf[count] >> 2); 857 } 858 } 859 if ((length % 3) != 2) 860 raw_count++; 861 tx_buf_raw[raw_count++] = SIXP_SEOF; 862 return raw_count; 863 } 864 865 /* decode 4 sixpack-encoded bytes into 3 data bytes */ 866 867 static void decode_data(struct sixpack *sp, unsigned char inbyte) 868 { 869 unsigned char *buf; 870 871 if (sp->rx_count != 3) { 872 sp->raw_buf[sp->rx_count++] = inbyte; 873 874 return; 875 } 876 877 buf = sp->raw_buf; 878 sp->cooked_buf[sp->rx_count_cooked++] = 879 buf[0] | ((buf[1] << 2) & 0xc0); 880 sp->cooked_buf[sp->rx_count_cooked++] = 881 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); 882 sp->cooked_buf[sp->rx_count_cooked++] = 883 (buf[2] & 0x03) | (inbyte << 2); 884 sp->rx_count = 0; 885 } 886 887 /* identify and execute a 6pack priority command byte */ 888 889 static void decode_prio_command(struct sixpack *sp, unsigned char cmd) 890 { 891 unsigned char channel; 892 int actual; 893 894 channel = cmd & SIXP_CHN_MASK; 895 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ 896 897 /* RX and DCD flags can only be set in the same prio command, 898 if the DCD flag has been set without the RX flag in the previous 899 prio command. If DCD has not been set before, something in the 900 transmission has gone wrong. In this case, RX and DCD are 901 cleared in order to prevent the decode_data routine from 902 reading further data that might be corrupt. */ 903 904 if (((sp->status & SIXP_DCD_MASK) == 0) && 905 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { 906 if (sp->status != 1) 907 printk(KERN_DEBUG "6pack: protocol violation\n"); 908 else 909 sp->status = 0; 910 cmd &= ~SIXP_RX_DCD_MASK; 911 } 912 sp->status = cmd & SIXP_PRIO_DATA_MASK; 913 } else { /* output watchdog char if idle */ 914 if ((sp->status2 != 0) && (sp->duplex == 1)) { 915 sp->led_state = 0x70; 916 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 917 sp->tx_enable = 1; 918 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); 919 sp->xleft -= actual; 920 sp->xhead += actual; 921 sp->led_state = 0x60; 922 sp->status2 = 0; 923 924 } 925 } 926 927 /* needed to trigger the TNC watchdog */ 928 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 929 930 /* if the state byte has been received, the TNC is present, 931 so the resync timer can be reset. */ 932 933 if (sp->tnc_state == TNC_IN_SYNC) { 934 del_timer(&sp->resync_t); 935 sp->resync_t.data = (unsigned long) sp; 936 sp->resync_t.function = resync_tnc; 937 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; 938 add_timer(&sp->resync_t); 939 } 940 941 sp->status1 = cmd & SIXP_PRIO_DATA_MASK; 942 } 943 944 /* identify and execute a standard 6pack command byte */ 945 946 static void decode_std_command(struct sixpack *sp, unsigned char cmd) 947 { 948 unsigned char checksum = 0, rest = 0, channel; 949 short i; 950 951 channel = cmd & SIXP_CHN_MASK; 952 switch (cmd & SIXP_CMD_MASK) { /* normal command */ 953 case SIXP_SEOF: 954 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { 955 if ((sp->status & SIXP_RX_DCD_MASK) == 956 SIXP_RX_DCD_MASK) { 957 sp->led_state = 0x68; 958 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 959 } 960 } else { 961 sp->led_state = 0x60; 962 /* fill trailing bytes with zeroes */ 963 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 964 rest = sp->rx_count; 965 if (rest != 0) 966 for (i = rest; i <= 3; i++) 967 decode_data(sp, 0); 968 if (rest == 2) 969 sp->rx_count_cooked -= 2; 970 else if (rest == 3) 971 sp->rx_count_cooked -= 1; 972 for (i = 0; i < sp->rx_count_cooked; i++) 973 checksum += sp->cooked_buf[i]; 974 if (checksum != SIXP_CHKSUM) { 975 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); 976 } else { 977 sp->rcount = sp->rx_count_cooked-2; 978 sp_bump(sp, 0); 979 } 980 sp->rx_count_cooked = 0; 981 } 982 break; 983 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); 984 break; 985 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); 986 break; 987 case SIXP_RX_BUF_OVL: 988 printk(KERN_DEBUG "6pack: RX buffer overflow\n"); 989 } 990 } 991 992 /* decode a 6pack packet */ 993 994 static void 995 sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) 996 { 997 unsigned char inbyte; 998 int count1; 999 1000 for (count1 = 0; count1 < count; count1++) { 1001 inbyte = pre_rbuff[count1]; 1002 if (inbyte == SIXP_FOUND_TNC) { 1003 tnc_set_sync_state(sp, TNC_IN_SYNC); 1004 del_timer(&sp->resync_t); 1005 } 1006 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) 1007 decode_prio_command(sp, inbyte); 1008 else if ((inbyte & SIXP_STD_CMD_MASK) != 0) 1009 decode_std_command(sp, inbyte); 1010 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) 1011 decode_data(sp, inbyte); 1012 } 1013 } 1014 1015 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); 1016 MODULE_DESCRIPTION("6pack driver for AX.25"); 1017 MODULE_LICENSE("GPL"); 1018 MODULE_ALIAS_LDISC(N_6PACK); 1019 1020 module_init(sixpack_init_driver); 1021 module_exit(sixpack_exit_driver); 1022