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 spin_lock_bh(&sp->lock); 251 /* We were not busy, so we are now... :-) */ 252 netif_stop_queue(dev); 253 dev->stats.tx_bytes += skb->len; 254 sp_encaps(sp, skb->data, skb->len); 255 spin_unlock_bh(&sp->lock); 256 257 dev_kfree_skb(skb); 258 259 return NETDEV_TX_OK; 260 } 261 262 static int sp_open_dev(struct net_device *dev) 263 { 264 struct sixpack *sp = netdev_priv(dev); 265 266 if (sp->tty == NULL) 267 return -ENODEV; 268 return 0; 269 } 270 271 /* Close the low-level part of the 6pack channel. */ 272 static int sp_close(struct net_device *dev) 273 { 274 struct sixpack *sp = netdev_priv(dev); 275 276 spin_lock_bh(&sp->lock); 277 if (sp->tty) { 278 /* TTY discipline is running. */ 279 clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); 280 } 281 netif_stop_queue(dev); 282 spin_unlock_bh(&sp->lock); 283 284 return 0; 285 } 286 287 /* Return the frame type ID */ 288 static int sp_header(struct sk_buff *skb, struct net_device *dev, 289 unsigned short type, const void *daddr, 290 const void *saddr, unsigned len) 291 { 292 #ifdef CONFIG_INET 293 if (type != ETH_P_AX25) 294 return ax25_hard_header(skb, dev, type, daddr, saddr, len); 295 #endif 296 return 0; 297 } 298 299 static int sp_set_mac_address(struct net_device *dev, void *addr) 300 { 301 struct sockaddr_ax25 *sa = addr; 302 303 netif_tx_lock_bh(dev); 304 netif_addr_lock(dev); 305 memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); 306 netif_addr_unlock(dev); 307 netif_tx_unlock_bh(dev); 308 309 return 0; 310 } 311 312 static int sp_rebuild_header(struct sk_buff *skb) 313 { 314 #ifdef CONFIG_INET 315 return ax25_rebuild_header(skb); 316 #else 317 return 0; 318 #endif 319 } 320 321 static const struct header_ops sp_header_ops = { 322 .create = sp_header, 323 .rebuild = sp_rebuild_header, 324 }; 325 326 static const struct net_device_ops sp_netdev_ops = { 327 .ndo_open = sp_open_dev, 328 .ndo_stop = sp_close, 329 .ndo_start_xmit = sp_xmit, 330 .ndo_set_mac_address = sp_set_mac_address, 331 }; 332 333 static void sp_setup(struct net_device *dev) 334 { 335 /* Finish setting up the DEVICE info. */ 336 dev->netdev_ops = &sp_netdev_ops; 337 dev->destructor = free_netdev; 338 dev->mtu = SIXP_MTU; 339 dev->hard_header_len = AX25_MAX_HEADER_LEN; 340 dev->header_ops = &sp_header_ops; 341 342 dev->addr_len = AX25_ADDR_LEN; 343 dev->type = ARPHRD_AX25; 344 dev->tx_queue_len = 10; 345 346 /* Only activated in AX.25 mode */ 347 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); 348 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); 349 350 dev->flags = 0; 351 } 352 353 /* Send one completely decapsulated IP datagram to the IP layer. */ 354 355 /* 356 * This is the routine that sends the received data to the kernel AX.25. 357 * 'cmd' is the KISS command. For AX.25 data, it is zero. 358 */ 359 360 static void sp_bump(struct sixpack *sp, char cmd) 361 { 362 struct sk_buff *skb; 363 int count; 364 unsigned char *ptr; 365 366 count = sp->rcount + 1; 367 368 sp->dev->stats.rx_bytes += count; 369 370 if ((skb = dev_alloc_skb(count)) == NULL) 371 goto out_mem; 372 373 ptr = skb_put(skb, count); 374 *ptr++ = cmd; /* KISS command */ 375 376 memcpy(ptr, sp->cooked_buf + 1, count); 377 skb->protocol = ax25_type_trans(skb, sp->dev); 378 netif_rx(skb); 379 sp->dev->stats.rx_packets++; 380 381 return; 382 383 out_mem: 384 sp->dev->stats.rx_dropped++; 385 } 386 387 388 /* ----------------------------------------------------------------------- */ 389 390 /* 391 * We have a potential race on dereferencing tty->disc_data, because the tty 392 * layer provides no locking at all - thus one cpu could be running 393 * sixpack_receive_buf while another calls sixpack_close, which zeroes 394 * tty->disc_data and frees the memory that sixpack_receive_buf is using. The 395 * best way to fix this is to use a rwlock in the tty struct, but for now we 396 * use a single global rwlock for all ttys in ppp line discipline. 397 */ 398 static DEFINE_RWLOCK(disc_data_lock); 399 400 static struct sixpack *sp_get(struct tty_struct *tty) 401 { 402 struct sixpack *sp; 403 404 read_lock(&disc_data_lock); 405 sp = tty->disc_data; 406 if (sp) 407 atomic_inc(&sp->refcnt); 408 read_unlock(&disc_data_lock); 409 410 return sp; 411 } 412 413 static void sp_put(struct sixpack *sp) 414 { 415 if (atomic_dec_and_test(&sp->refcnt)) 416 up(&sp->dead_sem); 417 } 418 419 /* 420 * Called by the TTY driver when there's room for more data. If we have 421 * more packets to send, we send them here. 422 */ 423 static void sixpack_write_wakeup(struct tty_struct *tty) 424 { 425 struct sixpack *sp = sp_get(tty); 426 int actual; 427 428 if (!sp) 429 return; 430 if (sp->xleft <= 0) { 431 /* Now serial buffer is almost free & we can start 432 * transmission of another packet */ 433 sp->dev->stats.tx_packets++; 434 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 435 sp->tx_enable = 0; 436 netif_wake_queue(sp->dev); 437 goto out; 438 } 439 440 if (sp->tx_enable) { 441 actual = tty->ops->write(tty, sp->xhead, sp->xleft); 442 sp->xleft -= actual; 443 sp->xhead += actual; 444 } 445 446 out: 447 sp_put(sp); 448 } 449 450 /* ----------------------------------------------------------------------- */ 451 452 /* 453 * Handle the 'receiver data ready' interrupt. 454 * This function is called by the 'tty_io' module in the kernel when 455 * a block of 6pack data has been received, which can now be decapsulated 456 * and sent on to some IP layer for further processing. 457 */ 458 static void sixpack_receive_buf(struct tty_struct *tty, 459 const unsigned char *cp, char *fp, int count) 460 { 461 struct sixpack *sp; 462 unsigned char buf[512]; 463 int count1; 464 465 if (!count) 466 return; 467 468 sp = sp_get(tty); 469 if (!sp) 470 return; 471 472 memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); 473 474 /* Read the characters out of the buffer */ 475 476 count1 = count; 477 while (count) { 478 count--; 479 if (fp && *fp++) { 480 if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) 481 sp->dev->stats.rx_errors++; 482 continue; 483 } 484 } 485 sixpack_decode(sp, buf, count1); 486 487 sp_put(sp); 488 tty_unthrottle(tty); 489 } 490 491 /* 492 * Try to resync the TNC. Called by the resync timer defined in 493 * decode_prio_command 494 */ 495 496 #define TNC_UNINITIALIZED 0 497 #define TNC_UNSYNC_STARTUP 1 498 #define TNC_UNSYNCED 2 499 #define TNC_IN_SYNC 3 500 501 static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) 502 { 503 char *msg; 504 505 switch (new_tnc_state) { 506 default: /* gcc oh piece-o-crap ... */ 507 case TNC_UNSYNC_STARTUP: 508 msg = "Synchronizing with TNC"; 509 break; 510 case TNC_UNSYNCED: 511 msg = "Lost synchronization with TNC\n"; 512 break; 513 case TNC_IN_SYNC: 514 msg = "Found TNC"; 515 break; 516 } 517 518 sp->tnc_state = new_tnc_state; 519 printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); 520 } 521 522 static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) 523 { 524 int old_tnc_state = sp->tnc_state; 525 526 if (old_tnc_state != new_tnc_state) 527 __tnc_set_sync_state(sp, new_tnc_state); 528 } 529 530 static void resync_tnc(unsigned long channel) 531 { 532 struct sixpack *sp = (struct sixpack *) channel; 533 static char resync_cmd = 0xe8; 534 535 /* clear any data that might have been received */ 536 537 sp->rx_count = 0; 538 sp->rx_count_cooked = 0; 539 540 /* reset state machine */ 541 542 sp->status = 1; 543 sp->status1 = 1; 544 sp->status2 = 0; 545 546 /* resync the TNC */ 547 548 sp->led_state = 0x60; 549 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 550 sp->tty->ops->write(sp->tty, &resync_cmd, 1); 551 552 553 /* Start resync timer again -- the TNC might be still absent */ 554 555 del_timer(&sp->resync_t); 556 sp->resync_t.data = (unsigned long) sp; 557 sp->resync_t.function = resync_tnc; 558 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; 559 add_timer(&sp->resync_t); 560 } 561 562 static inline int tnc_init(struct sixpack *sp) 563 { 564 unsigned char inbyte = 0xe8; 565 566 tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); 567 568 sp->tty->ops->write(sp->tty, &inbyte, 1); 569 570 del_timer(&sp->resync_t); 571 sp->resync_t.data = (unsigned long) sp; 572 sp->resync_t.function = resync_tnc; 573 sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; 574 add_timer(&sp->resync_t); 575 576 return 0; 577 } 578 579 /* 580 * Open the high-level part of the 6pack channel. 581 * This function is called by the TTY module when the 582 * 6pack line discipline is called for. Because we are 583 * sure the tty line exists, we only have to link it to 584 * a free 6pcack channel... 585 */ 586 static int sixpack_open(struct tty_struct *tty) 587 { 588 char *rbuff = NULL, *xbuff = NULL; 589 struct net_device *dev; 590 struct sixpack *sp; 591 unsigned long len; 592 int err = 0; 593 594 if (!capable(CAP_NET_ADMIN)) 595 return -EPERM; 596 if (tty->ops->write == NULL) 597 return -EOPNOTSUPP; 598 599 dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup); 600 if (!dev) { 601 err = -ENOMEM; 602 goto out; 603 } 604 605 sp = netdev_priv(dev); 606 sp->dev = dev; 607 608 spin_lock_init(&sp->lock); 609 atomic_set(&sp->refcnt, 1); 610 sema_init(&sp->dead_sem, 0); 611 612 /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ 613 614 len = dev->mtu * 2; 615 616 rbuff = kmalloc(len + 4, GFP_KERNEL); 617 xbuff = kmalloc(len + 4, GFP_KERNEL); 618 619 if (rbuff == NULL || xbuff == NULL) { 620 err = -ENOBUFS; 621 goto out_free; 622 } 623 624 spin_lock_bh(&sp->lock); 625 626 sp->tty = tty; 627 628 sp->rbuff = rbuff; 629 sp->xbuff = xbuff; 630 631 sp->mtu = AX25_MTU + 73; 632 sp->buffsize = len; 633 sp->rcount = 0; 634 sp->rx_count = 0; 635 sp->rx_count_cooked = 0; 636 sp->xleft = 0; 637 638 sp->flags = 0; /* Clear ESCAPE & ERROR flags */ 639 640 sp->duplex = 0; 641 sp->tx_delay = SIXP_TXDELAY; 642 sp->persistence = SIXP_PERSIST; 643 sp->slottime = SIXP_SLOTTIME; 644 sp->led_state = 0x60; 645 sp->status = 1; 646 sp->status1 = 1; 647 sp->status2 = 0; 648 sp->tx_enable = 0; 649 650 netif_start_queue(dev); 651 652 init_timer(&sp->tx_t); 653 sp->tx_t.function = sp_xmit_on_air; 654 sp->tx_t.data = (unsigned long) sp; 655 656 init_timer(&sp->resync_t); 657 658 spin_unlock_bh(&sp->lock); 659 660 /* Done. We have linked the TTY line to a channel. */ 661 tty->disc_data = sp; 662 tty->receive_room = 65536; 663 664 /* Now we're ready to register. */ 665 if (register_netdev(dev)) 666 goto out_free; 667 668 tnc_init(sp); 669 670 return 0; 671 672 out_free: 673 kfree(xbuff); 674 kfree(rbuff); 675 676 if (dev) 677 free_netdev(dev); 678 679 out: 680 return err; 681 } 682 683 684 /* 685 * Close down a 6pack channel. 686 * This means flushing out any pending queues, and then restoring the 687 * TTY line discipline to what it was before it got hooked to 6pack 688 * (which usually is TTY again). 689 */ 690 static void sixpack_close(struct tty_struct *tty) 691 { 692 struct sixpack *sp; 693 694 write_lock_bh(&disc_data_lock); 695 sp = tty->disc_data; 696 tty->disc_data = NULL; 697 write_unlock_bh(&disc_data_lock); 698 if (!sp) 699 return; 700 701 /* 702 * We have now ensured that nobody can start using ap from now on, but 703 * we have to wait for all existing users to finish. 704 */ 705 if (!atomic_dec_and_test(&sp->refcnt)) 706 down(&sp->dead_sem); 707 708 unregister_netdev(sp->dev); 709 710 del_timer(&sp->tx_t); 711 del_timer(&sp->resync_t); 712 713 /* Free all 6pack frame buffers. */ 714 kfree(sp->rbuff); 715 kfree(sp->xbuff); 716 } 717 718 /* Perform I/O control on an active 6pack channel. */ 719 static int sixpack_ioctl(struct tty_struct *tty, struct file *file, 720 unsigned int cmd, unsigned long arg) 721 { 722 struct sixpack *sp = sp_get(tty); 723 struct net_device *dev; 724 unsigned int tmp, err; 725 726 if (!sp) 727 return -ENXIO; 728 dev = sp->dev; 729 730 switch(cmd) { 731 case SIOCGIFNAME: 732 err = copy_to_user((void __user *) arg, dev->name, 733 strlen(dev->name) + 1) ? -EFAULT : 0; 734 break; 735 736 case SIOCGIFENCAP: 737 err = put_user(0, (int __user *) arg); 738 break; 739 740 case SIOCSIFENCAP: 741 if (get_user(tmp, (int __user *) arg)) { 742 err = -EFAULT; 743 break; 744 } 745 746 sp->mode = tmp; 747 dev->addr_len = AX25_ADDR_LEN; 748 dev->hard_header_len = AX25_KISS_HEADER_LEN + 749 AX25_MAX_HEADER_LEN + 3; 750 dev->type = ARPHRD_AX25; 751 752 err = 0; 753 break; 754 755 case SIOCSIFHWADDR: { 756 char addr[AX25_ADDR_LEN]; 757 758 if (copy_from_user(&addr, 759 (void __user *) arg, AX25_ADDR_LEN)) { 760 err = -EFAULT; 761 break; 762 } 763 764 netif_tx_lock_bh(dev); 765 memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); 766 netif_tx_unlock_bh(dev); 767 768 err = 0; 769 break; 770 } 771 772 default: 773 err = tty_mode_ioctl(tty, file, cmd, arg); 774 } 775 776 sp_put(sp); 777 778 return err; 779 } 780 781 #ifdef CONFIG_COMPAT 782 static long sixpack_compat_ioctl(struct tty_struct * tty, struct file * file, 783 unsigned int cmd, unsigned long arg) 784 { 785 switch (cmd) { 786 case SIOCGIFNAME: 787 case SIOCGIFENCAP: 788 case SIOCSIFENCAP: 789 case SIOCSIFHWADDR: 790 return sixpack_ioctl(tty, file, cmd, 791 (unsigned long)compat_ptr(arg)); 792 } 793 794 return -ENOIOCTLCMD; 795 } 796 #endif 797 798 static struct tty_ldisc_ops sp_ldisc = { 799 .owner = THIS_MODULE, 800 .magic = TTY_LDISC_MAGIC, 801 .name = "6pack", 802 .open = sixpack_open, 803 .close = sixpack_close, 804 .ioctl = sixpack_ioctl, 805 #ifdef CONFIG_COMPAT 806 .compat_ioctl = sixpack_compat_ioctl, 807 #endif 808 .receive_buf = sixpack_receive_buf, 809 .write_wakeup = sixpack_write_wakeup, 810 }; 811 812 /* Initialize 6pack control device -- register 6pack line discipline */ 813 814 static const char msg_banner[] __initconst = KERN_INFO \ 815 "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; 816 static const char msg_regfail[] __initconst = KERN_ERR \ 817 "6pack: can't register line discipline (err = %d)\n"; 818 819 static int __init sixpack_init_driver(void) 820 { 821 int status; 822 823 printk(msg_banner); 824 825 /* Register the provided line protocol discipline */ 826 if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) 827 printk(msg_regfail, status); 828 829 return status; 830 } 831 832 static const char msg_unregfail[] = KERN_ERR \ 833 "6pack: can't unregister line discipline (err = %d)\n"; 834 835 static void __exit sixpack_exit_driver(void) 836 { 837 int ret; 838 839 if ((ret = tty_unregister_ldisc(N_6PACK))) 840 printk(msg_unregfail, ret); 841 } 842 843 /* encode an AX.25 packet into 6pack */ 844 845 static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, 846 int length, unsigned char tx_delay) 847 { 848 int count = 0; 849 unsigned char checksum = 0, buf[400]; 850 int raw_count = 0; 851 852 tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; 853 tx_buf_raw[raw_count++] = SIXP_SEOF; 854 855 buf[0] = tx_delay; 856 for (count = 1; count < length; count++) 857 buf[count] = tx_buf[count]; 858 859 for (count = 0; count < length; count++) 860 checksum += buf[count]; 861 buf[length] = (unsigned char) 0xff - checksum; 862 863 for (count = 0; count <= length; count++) { 864 if ((count % 3) == 0) { 865 tx_buf_raw[raw_count++] = (buf[count] & 0x3f); 866 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); 867 } else if ((count % 3) == 1) { 868 tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); 869 tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); 870 } else { 871 tx_buf_raw[raw_count++] |= (buf[count] & 0x03); 872 tx_buf_raw[raw_count++] = (buf[count] >> 2); 873 } 874 } 875 if ((length % 3) != 2) 876 raw_count++; 877 tx_buf_raw[raw_count++] = SIXP_SEOF; 878 return raw_count; 879 } 880 881 /* decode 4 sixpack-encoded bytes into 3 data bytes */ 882 883 static void decode_data(struct sixpack *sp, unsigned char inbyte) 884 { 885 unsigned char *buf; 886 887 if (sp->rx_count != 3) { 888 sp->raw_buf[sp->rx_count++] = inbyte; 889 890 return; 891 } 892 893 buf = sp->raw_buf; 894 sp->cooked_buf[sp->rx_count_cooked++] = 895 buf[0] | ((buf[1] << 2) & 0xc0); 896 sp->cooked_buf[sp->rx_count_cooked++] = 897 (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); 898 sp->cooked_buf[sp->rx_count_cooked++] = 899 (buf[2] & 0x03) | (inbyte << 2); 900 sp->rx_count = 0; 901 } 902 903 /* identify and execute a 6pack priority command byte */ 904 905 static void decode_prio_command(struct sixpack *sp, unsigned char cmd) 906 { 907 unsigned char channel; 908 int actual; 909 910 channel = cmd & SIXP_CHN_MASK; 911 if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ 912 913 /* RX and DCD flags can only be set in the same prio command, 914 if the DCD flag has been set without the RX flag in the previous 915 prio command. If DCD has not been set before, something in the 916 transmission has gone wrong. In this case, RX and DCD are 917 cleared in order to prevent the decode_data routine from 918 reading further data that might be corrupt. */ 919 920 if (((sp->status & SIXP_DCD_MASK) == 0) && 921 ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { 922 if (sp->status != 1) 923 printk(KERN_DEBUG "6pack: protocol violation\n"); 924 else 925 sp->status = 0; 926 cmd &= ~SIXP_RX_DCD_MASK; 927 } 928 sp->status = cmd & SIXP_PRIO_DATA_MASK; 929 } else { /* output watchdog char if idle */ 930 if ((sp->status2 != 0) && (sp->duplex == 1)) { 931 sp->led_state = 0x70; 932 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 933 sp->tx_enable = 1; 934 actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); 935 sp->xleft -= actual; 936 sp->xhead += actual; 937 sp->led_state = 0x60; 938 sp->status2 = 0; 939 940 } 941 } 942 943 /* needed to trigger the TNC watchdog */ 944 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 945 946 /* if the state byte has been received, the TNC is present, 947 so the resync timer can be reset. */ 948 949 if (sp->tnc_state == TNC_IN_SYNC) { 950 del_timer(&sp->resync_t); 951 sp->resync_t.data = (unsigned long) sp; 952 sp->resync_t.function = resync_tnc; 953 sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; 954 add_timer(&sp->resync_t); 955 } 956 957 sp->status1 = cmd & SIXP_PRIO_DATA_MASK; 958 } 959 960 /* identify and execute a standard 6pack command byte */ 961 962 static void decode_std_command(struct sixpack *sp, unsigned char cmd) 963 { 964 unsigned char checksum = 0, rest = 0, channel; 965 short i; 966 967 channel = cmd & SIXP_CHN_MASK; 968 switch (cmd & SIXP_CMD_MASK) { /* normal command */ 969 case SIXP_SEOF: 970 if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { 971 if ((sp->status & SIXP_RX_DCD_MASK) == 972 SIXP_RX_DCD_MASK) { 973 sp->led_state = 0x68; 974 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 975 } 976 } else { 977 sp->led_state = 0x60; 978 /* fill trailing bytes with zeroes */ 979 sp->tty->ops->write(sp->tty, &sp->led_state, 1); 980 rest = sp->rx_count; 981 if (rest != 0) 982 for (i = rest; i <= 3; i++) 983 decode_data(sp, 0); 984 if (rest == 2) 985 sp->rx_count_cooked -= 2; 986 else if (rest == 3) 987 sp->rx_count_cooked -= 1; 988 for (i = 0; i < sp->rx_count_cooked; i++) 989 checksum += sp->cooked_buf[i]; 990 if (checksum != SIXP_CHKSUM) { 991 printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); 992 } else { 993 sp->rcount = sp->rx_count_cooked-2; 994 sp_bump(sp, 0); 995 } 996 sp->rx_count_cooked = 0; 997 } 998 break; 999 case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); 1000 break; 1001 case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); 1002 break; 1003 case SIXP_RX_BUF_OVL: 1004 printk(KERN_DEBUG "6pack: RX buffer overflow\n"); 1005 } 1006 } 1007 1008 /* decode a 6pack packet */ 1009 1010 static void 1011 sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) 1012 { 1013 unsigned char inbyte; 1014 int count1; 1015 1016 for (count1 = 0; count1 < count; count1++) { 1017 inbyte = pre_rbuff[count1]; 1018 if (inbyte == SIXP_FOUND_TNC) { 1019 tnc_set_sync_state(sp, TNC_IN_SYNC); 1020 del_timer(&sp->resync_t); 1021 } 1022 if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) 1023 decode_prio_command(sp, inbyte); 1024 else if ((inbyte & SIXP_STD_CMD_MASK) != 0) 1025 decode_std_command(sp, inbyte); 1026 else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) 1027 decode_data(sp, inbyte); 1028 } 1029 } 1030 1031 MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); 1032 MODULE_DESCRIPTION("6pack driver for AX.25"); 1033 MODULE_LICENSE("GPL"); 1034 MODULE_ALIAS_LDISC(N_6PACK); 1035 1036 module_init(sixpack_init_driver); 1037 module_exit(sixpack_exit_driver); 1038