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 *, const 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 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 int count1; 440 441 if (!count) 442 return; 443 444 sp = sp_get(tty); 445 if (!sp) 446 return; 447 448 /* Read the characters out of the buffer */ 449 count1 = count; 450 while (count) { 451 count--; 452 if (fp && *fp++) { 453 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) 454 sp->dev->stats.rx_errors++; 455 continue; 456 } 457 } 458 sixpack_decode(sp, cp, count1); 459 460 sp_put(sp); 461 tty_unthrottle(tty); 462 } 463 464 /* 465 * Try to resync the TNC. Called by the resync timer defined in 466 * decode_prio_command 467 */ 468 469 #define TNC_UNINITIALIZED 0 470 #define TNC_UNSYNC_STARTUP 1 471 #define TNC_UNSYNCED 2 472 #define TNC_IN_SYNC 3 473 474 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) 475 { 476 char *msg; 477 478 switch (new_tnc_state) { 479 default: /* gcc oh piece-o-crap ... */ 480 case TNC_UNSYNC_STARTUP: 481 msg = "Synchronizing with TNC"; 482 break; 483 case TNC_UNSYNCED: 484 msg = "Lost synchronization with TNC\n"; 485 break; 486 case TNC_IN_SYNC: 487 msg = "Found TNC"; 488 break; 489 } 490 491 sp->tnc_state = new_tnc_state; 492 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); 493 } 494 495 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) 496 { 497 int old_tnc_state = sp->tnc_state; 498 499 if (old_tnc_state != new_tnc_state) 500 __tnc_set_sync_state(sp, new_tnc_state); 501 } 502 503 static void resync_tnc(unsigned long channel) 504 { 505 struct sixpack *sp = (struct sixpack *) channel; 506 static char resync_cmd = 0xe8; 507 508 /* clear any data that might have been received */ 509 510 sp->rx_count = 0; 511 sp->rx_count_cooked = 0; 512 513 /* reset state machine */ 514 515 sp->status = 1; 516 sp->status1 = 1; 517 sp->status2 = 0; 518 519 /* resync the TNC */ 520 521 sp->led_state = 0x60; 522 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 523 sp->tty->ops->write(sp->tty, &resync_cmd, 1); 524 525 526 /* Start resync timer again -- the TNC might be still absent */ 527 528 del_timer(&sp->resync_t); 529 sp->resync_t.data = (unsigned long) sp; 530 sp->resync_t.function = resync_tnc; 531 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; 532 add_timer(&sp->resync_t); 533 } 534 535 static inline int tnc_init(struct sixpack *sp) 536 { 537 unsigned char inbyte = 0xe8; 538 539 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); 540 541 sp->tty->ops->write(sp->tty, &inbyte, 1); 542 543 del_timer(&sp->resync_t); 544 sp->resync_t.data = (unsigned long) sp; 545 sp->resync_t.function = resync_tnc; 546 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; 547 add_timer(&sp->resync_t); 548 549 return 0; 550 } 551 552 /* 553 * Open the high-level part of the 6pack channel. 554 * This function is called by the TTY module when the 555 * 6pack line discipline is called for. Because we are 556 * sure the tty line exists, we only have to link it to 557 * a free 6pcack channel... 558 */ 559 static int sixpack_open(struct tty_struct *tty) 560 { 561 char *rbuff = NULL, *xbuff = NULL; 562 struct net_device *dev; 563 struct sixpack *sp; 564 unsigned long len; 565 int err = 0; 566 567 if (!capable(CAP_NET_ADMIN)) 568 return -EPERM; 569 if (tty->ops->write == NULL) 570 return -EOPNOTSUPP; 571 572 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", NET_NAME_UNKNOWN, 573 sp_setup); 574 if (!dev) { 575 err = -ENOMEM; 576 goto out; 577 } 578 579 sp = netdev_priv(dev); 580 sp->dev = dev; 581 582 spin_lock_init(&sp->lock); 583 atomic_set(&sp->refcnt, 1); 584 sema_init(&sp->dead_sem, 0); 585 586 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ 587 588 len = dev->mtu * 2; 589 590 rbuff = kmalloc(len + 4, GFP_KERNEL); 591 xbuff = kmalloc(len + 4, GFP_KERNEL); 592 593 if (rbuff == NULL || xbuff == NULL) { 594 err = -ENOBUFS; 595 goto out_free; 596 } 597 598 spin_lock_bh(&sp->lock); 599 600 sp->tty = tty; 601 602 sp->rbuff = rbuff; 603 sp->xbuff = xbuff; 604 605 sp->mtu = AX25_MTU + 73; 606 sp->buffsize = len; 607 sp->rcount = 0; 608 sp->rx_count = 0; 609 sp->rx_count_cooked = 0; 610 sp->xleft = 0; 611 612 sp->flags = 0; /* Clear ESCAPE & ERROR flags */ 613 614 sp->duplex = 0; 615 sp->tx_delay = SIXP_TXDELAY; 616 sp->persistence = SIXP_PERSIST; 617 sp->slottime = SIXP_SLOTTIME; 618 sp->led_state = 0x60; 619 sp->status = 1; 620 sp->status1 = 1; 621 sp->status2 = 0; 622 sp->tx_enable = 0; 623 624 netif_start_queue(dev); 625 626 init_timer(&sp->tx_t); 627 sp->tx_t.function = sp_xmit_on_air; 628 sp->tx_t.data = (unsigned long) sp; 629 630 init_timer(&sp->resync_t); 631 632 spin_unlock_bh(&sp->lock); 633 634 /* Done. We have linked the TTY line to a channel. */ 635 tty->disc_data = sp; 636 tty->receive_room = 65536; 637 638 /* Now we're ready to register. */ 639 err = register_netdev(dev); 640 if (err) 641 goto out_free; 642 643 tnc_init(sp); 644 645 return 0; 646 647 out_free: 648 kfree(xbuff); 649 kfree(rbuff); 650 651 free_netdev(dev); 652 653 out: 654 return err; 655 } 656 657 658 /* 659 * Close down a 6pack channel. 660 * This means flushing out any pending queues, and then restoring the 661 * TTY line discipline to what it was before it got hooked to 6pack 662 * (which usually is TTY again). 663 */ 664 static void sixpack_close(struct tty_struct *tty) 665 { 666 struct sixpack *sp; 667 668 write_lock_bh(&disc_data_lock); 669 sp = tty->disc_data; 670 tty->disc_data = NULL; 671 write_unlock_bh(&disc_data_lock); 672 if (!sp) 673 return; 674 675 /* 676 * We have now ensured that nobody can start using ap from now on, but 677 * we have to wait for all existing users to finish. 678 */ 679 if (!atomic_dec_and_test(&sp->refcnt)) 680 down(&sp->dead_sem); 681 682 /* We must stop the queue to avoid potentially scribbling 683 * on the free buffers. The sp->dead_sem is not sufficient 684 * to protect us from sp->xbuff access. 685 */ 686 netif_stop_queue(sp->dev); 687 688 del_timer_sync(&sp->tx_t); 689 del_timer_sync(&sp->resync_t); 690 691 /* Free all 6pack frame buffers. */ 692 kfree(sp->rbuff); 693 kfree(sp->xbuff); 694 695 unregister_netdev(sp->dev); 696 } 697 698 /* Perform I/O control on an active 6pack channel. */ 699 static int sixpack_ioctl(struct tty_struct *tty, struct file *file, 700 unsigned int cmd, unsigned long arg) 701 { 702 struct sixpack *sp = sp_get(tty); 703 struct net_device *dev; 704 unsigned int tmp, err; 705 706 if (!sp) 707 return -ENXIO; 708 dev = sp->dev; 709 710 switch(cmd) { 711 case SIOCGIFNAME: 712 err = copy_to_user((void __user *) arg, dev->name, 713 strlen(dev->name) + 1) ? -EFAULT : 0; 714 break; 715 716 case SIOCGIFENCAP: 717 err = put_user(0, (int __user *) arg); 718 break; 719 720 case SIOCSIFENCAP: 721 if (get_user(tmp, (int __user *) arg)) { 722 err = -EFAULT; 723 break; 724 } 725 726 sp->mode = tmp; 727 dev->addr_len = AX25_ADDR_LEN; 728 dev->hard_header_len = AX25_KISS_HEADER_LEN + 729 AX25_MAX_HEADER_LEN + 3; 730 dev->type = ARPHRD_AX25; 731 732 err = 0; 733 break; 734 735 case SIOCSIFHWADDR: { 736 char addr[AX25_ADDR_LEN]; 737 738 if (copy_from_user(&addr, 739 (void __user *) arg, AX25_ADDR_LEN)) { 740 err = -EFAULT; 741 break; 742 } 743 744 netif_tx_lock_bh(dev); 745 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); 746 netif_tx_unlock_bh(dev); 747 748 err = 0; 749 break; 750 } 751 752 default: 753 err = tty_mode_ioctl(tty, file, cmd, arg); 754 } 755 756 sp_put(sp); 757 758 return err; 759 } 760 761 #ifdef CONFIG_COMPAT 762 static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file, 763 unsigned int cmd, unsigned long arg) 764 { 765 switch (cmd) { 766 case SIOCGIFNAME: 767 case SIOCGIFENCAP: 768 case SIOCSIFENCAP: 769 case SIOCSIFHWADDR: 770 return sixpack_ioctl(tty, file, cmd, 771 (unsigned long)compat_ptr(arg)); 772 } 773 774 return -ENOIOCTLCMD; 775 } 776 #endif 777 778 static struct tty_ldisc_ops sp_ldisc = { 779 .owner = THIS_MODULE, 780 .magic = TTY_LDISC_MAGIC, 781 .name = "6pack", 782 .open = sixpack_open, 783 .close = sixpack_close, 784 .ioctl = sixpack_ioctl, 785 #ifdef CONFIG_COMPAT 786 .compat_ioctl = sixpack_compat_ioctl, 787 #endif 788 .receive_buf = sixpack_receive_buf, 789 .write_wakeup = sixpack_write_wakeup, 790 }; 791 792 /* Initialize 6pack control device -- register 6pack line discipline */ 793 794 static const char msg_banner[] __initconst = KERN_INFO \ 795 "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; 796 static const char msg_regfail[] __initconst = KERN_ERR \ 797 "6pack: can't register line discipline (err = %d)\n"; 798 799 static int __init sixpack_init_driver(void) 800 { 801 int status; 802 803 printk(msg_banner); 804 805 /* Register the provided line protocol discipline */ 806 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) 807 printk(msg_regfail, status); 808 809 return status; 810 } 811 812 static const char msg_unregfail[] = KERN_ERR \ 813 "6pack: can't unregister line discipline (err = %d)\n"; 814 815 static void __exit sixpack_exit_driver(void) 816 { 817 int ret; 818 819 if ((ret = tty_unregister_ldisc(N_6PACK))) 820 printk(msg_unregfail, ret); 821 } 822 823 /* encode an AX.25 packet into 6pack */ 824 825 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, 826 int length, unsigned char tx_delay) 827 { 828 int count = 0; 829 unsigned char checksum = 0, buf[400]; 830 int raw_count = 0; 831 832 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; 833 tx_buf_raw[raw_count++] = SIXP_SEOF; 834 835 buf[0] = tx_delay; 836 for (count = 1; count < length; count++) 837 buf[count] = tx_buf[count]; 838 839 for (count = 0; count < length; count++) 840 checksum += buf[count]; 841 buf[length] = (unsigned char) 0xff - checksum; 842 843 for (count = 0; count <= length; count++) { 844 if ((count % 3) == 0) { 845 tx_buf_raw[raw_count++] = (buf[count] & 0x3f); 846 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); 847 } else if ((count % 3) == 1) { 848 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); 849 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); 850 } else { 851 tx_buf_raw[raw_count++] |= (buf[count] & 0x03); 852 tx_buf_raw[raw_count++] = (buf[count] >> 2); 853 } 854 } 855 if ((length % 3) != 2) 856 raw_count++; 857 tx_buf_raw[raw_count++] = SIXP_SEOF; 858 return raw_count; 859 } 860 861 /* decode 4 sixpack-encoded bytes into 3 data bytes */ 862 863 static void decode_data(struct sixpack *sp, unsigned char inbyte) 864 { 865 unsigned char *buf; 866 867 if (sp->rx_count != 3) { 868 sp->raw_buf[sp->rx_count++] = inbyte; 869 870 return; 871 } 872 873 buf = sp->raw_buf; 874 sp->cooked_buf[sp->rx_count_cooked++] = 875 buf[0] | ((buf[1] << 2) & 0xc0); 876 sp->cooked_buf[sp->rx_count_cooked++] = 877 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); 878 sp->cooked_buf[sp->rx_count_cooked++] = 879 (buf[2] & 0x03) | (inbyte << 2); 880 sp->rx_count = 0; 881 } 882 883 /* identify and execute a 6pack priority command byte */ 884 885 static void decode_prio_command(struct sixpack *sp, unsigned char cmd) 886 { 887 unsigned char channel; 888 int actual; 889 890 channel = cmd & SIXP_CHN_MASK; 891 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ 892 893 /* RX and DCD flags can only be set in the same prio command, 894 if the DCD flag has been set without the RX flag in the previous 895 prio command. If DCD has not been set before, something in the 896 transmission has gone wrong. In this case, RX and DCD are 897 cleared in order to prevent the decode_data routine from 898 reading further data that might be corrupt. */ 899 900 if (((sp->status & SIXP_DCD_MASK) == 0) && 901 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { 902 if (sp->status != 1) 903 printk(KERN_DEBUG "6pack: protocol violation\n"); 904 else 905 sp->status = 0; 906 cmd &= ~SIXP_RX_DCD_MASK; 907 } 908 sp->status = cmd & SIXP_PRIO_DATA_MASK; 909 } else { /* output watchdog char if idle */ 910 if ((sp->status2 != 0) && (sp->duplex == 1)) { 911 sp->led_state = 0x70; 912 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 913 sp->tx_enable = 1; 914 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); 915 sp->xleft -= actual; 916 sp->xhead += actual; 917 sp->led_state = 0x60; 918 sp->status2 = 0; 919 920 } 921 } 922 923 /* needed to trigger the TNC watchdog */ 924 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 925 926 /* if the state byte has been received, the TNC is present, 927 so the resync timer can be reset. */ 928 929 if (sp->tnc_state == TNC_IN_SYNC) { 930 del_timer(&sp->resync_t); 931 sp->resync_t.data = (unsigned long) sp; 932 sp->resync_t.function = resync_tnc; 933 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; 934 add_timer(&sp->resync_t); 935 } 936 937 sp->status1 = cmd & SIXP_PRIO_DATA_MASK; 938 } 939 940 /* identify and execute a standard 6pack command byte */ 941 942 static void decode_std_command(struct sixpack *sp, unsigned char cmd) 943 { 944 unsigned char checksum = 0, rest = 0, channel; 945 short i; 946 947 channel = cmd & SIXP_CHN_MASK; 948 switch (cmd & SIXP_CMD_MASK) { /* normal command */ 949 case SIXP_SEOF: 950 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { 951 if ((sp->status & SIXP_RX_DCD_MASK) == 952 SIXP_RX_DCD_MASK) { 953 sp->led_state = 0x68; 954 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 955 } 956 } else { 957 sp->led_state = 0x60; 958 /* fill trailing bytes with zeroes */ 959 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 960 rest = sp->rx_count; 961 if (rest != 0) 962 for (i = rest; i <= 3; i++) 963 decode_data(sp, 0); 964 if (rest == 2) 965 sp->rx_count_cooked -= 2; 966 else if (rest == 3) 967 sp->rx_count_cooked -= 1; 968 for (i = 0; i < sp->rx_count_cooked; i++) 969 checksum += sp->cooked_buf[i]; 970 if (checksum != SIXP_CHKSUM) { 971 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); 972 } else { 973 sp->rcount = sp->rx_count_cooked-2; 974 sp_bump(sp, 0); 975 } 976 sp->rx_count_cooked = 0; 977 } 978 break; 979 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); 980 break; 981 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); 982 break; 983 case SIXP_RX_BUF_OVL: 984 printk(KERN_DEBUG "6pack: RX buffer overflow\n"); 985 } 986 } 987 988 /* decode a 6pack packet */ 989 990 static void 991 sixpack_decode(struct sixpack *sp, const unsigned char *pre_rbuff, int count) 992 { 993 unsigned char inbyte; 994 int count1; 995 996 for (count1 = 0; count1 < count; count1++) { 997 inbyte = pre_rbuff[count1]; 998 if (inbyte == SIXP_FOUND_TNC) { 999 tnc_set_sync_state(sp, TNC_IN_SYNC); 1000 del_timer(&sp->resync_t); 1001 } 1002 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) 1003 decode_prio_command(sp, inbyte); 1004 else if ((inbyte & SIXP_STD_CMD_MASK) != 0) 1005 decode_std_command(sp, inbyte); 1006 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) 1007 decode_data(sp, inbyte); 1008 } 1009 } 1010 1011 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); 1012 MODULE_DESCRIPTION("6pack driver for AX.25"); 1013 MODULE_LICENSE("GPL"); 1014 MODULE_ALIAS_LDISC(N_6PACK); 1015 1016 module_init(sixpack_init_driver); 1017 module_exit(sixpack_exit_driver); 1018