1 /* 2 * slip.c This module implements the SLIP protocol for kernel-based 3 * devices like TTY. It interfaces between a raw TTY, and the 4 * kernel's INET protocol layers. 5 * 6 * Version: @(#)slip.c 0.8.3 12/24/94 7 * 8 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk> 9 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> 10 * 11 * Fixes: 12 * Alan Cox : Sanity checks and avoid tx overruns. 13 * Has a new sl->mtu field. 14 * Alan Cox : Found cause of overrun. ifconfig sl0 15 * mtu upwards. Driver now spots this 16 * and grows/shrinks its buffers(hack!). 17 * Memory leak if you run out of memory 18 * setting up a slip driver fixed. 19 * Matt Dillon : Printable slip (borrowed from NET2E) 20 * Pauline Middelink : Slip driver fixes. 21 * Alan Cox : Honours the old SL_COMPRESSED flag 22 * Alan Cox : KISS AX.25 and AXUI IP support 23 * Michael Riepe : Automatic CSLIP recognition added 24 * Charles Hedrick : CSLIP header length problem fix. 25 * Alan Cox : Corrected non-IP cases of the above. 26 * Alan Cox : Now uses hardware type as per FvK. 27 * Alan Cox : Default to 192.168.0.0 (RFC 1597) 28 * A.N.Kuznetsov : dev_tint() recursion fix. 29 * Dmitry Gorodchanin : SLIP memory leaks 30 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver 31 * buffering from 4096 to 256 bytes. 32 * Improving SLIP response time. 33 * CONFIG_SLIP_MODE_SLIP6. 34 * ifconfig sl? up & down now works 35 * correctly. 36 * Modularization. 37 * Alan Cox : Oops - fix AX.25 buffer lengths 38 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP 39 * statistics. Include CSLIP code only 40 * if it really needed. 41 * Alan Cox : Free slhc buffers in the right place. 42 * Alan Cox : Allow for digipeated IP over AX.25 43 * Matti Aarnio : Dynamic SLIP devices, with ideas taken 44 * from Jim Freeman's <jfree@caldera.com> 45 * dynamic PPP devices. We do NOT kfree() 46 * device entries, just reg./unreg. them 47 * as they are needed. We kfree() them 48 * at module cleanup. 49 * With MODULE-loading ``insmod'', user 50 * can issue parameter: slip_maxdev=1024 51 * (Or how much he/she wants.. Default 52 * is 256) 53 * Stanislav Voronyi : Slip line checking, with ideas taken 54 * from multislip BSDI driver which was 55 * written by Igor Chechik, RELCOM Corp. 56 * Only algorithms have been ported to 57 * Linux SLIP driver. 58 * Vitaly E. Lavrov : Sane behaviour on tty hangup. 59 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice 60 * modules. 61 */ 62 63 #define SL_CHECK_TRANSMIT 64 #include <linux/module.h> 65 #include <linux/moduleparam.h> 66 67 #include <linux/uaccess.h> 68 #include <linux/bitops.h> 69 #include <linux/sched/signal.h> 70 #include <linux/string.h> 71 #include <linux/mm.h> 72 #include <linux/interrupt.h> 73 #include <linux/in.h> 74 #include <linux/tty.h> 75 #include <linux/errno.h> 76 #include <linux/netdevice.h> 77 #include <linux/etherdevice.h> 78 #include <linux/skbuff.h> 79 #include <linux/rtnetlink.h> 80 #include <linux/if_arp.h> 81 #include <linux/if_slip.h> 82 #include <linux/compat.h> 83 #include <linux/delay.h> 84 #include <linux/init.h> 85 #include <linux/slab.h> 86 #include <linux/workqueue.h> 87 #include "slip.h" 88 #ifdef CONFIG_INET 89 #include <linux/ip.h> 90 #include <linux/tcp.h> 91 #include <net/slhc_vj.h> 92 #endif 93 94 #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY" 95 96 static struct net_device **slip_devs; 97 98 static int slip_maxdev = SL_NRUNIT; 99 module_param(slip_maxdev, int, 0); 100 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices"); 101 102 static int slip_esc(unsigned char *p, unsigned char *d, int len); 103 static void slip_unesc(struct slip *sl, unsigned char c); 104 #ifdef CONFIG_SLIP_MODE_SLIP6 105 static int slip_esc6(unsigned char *p, unsigned char *d, int len); 106 static void slip_unesc6(struct slip *sl, unsigned char c); 107 #endif 108 #ifdef CONFIG_SLIP_SMART 109 static void sl_keepalive(unsigned long sls); 110 static void sl_outfill(unsigned long sls); 111 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd); 112 #endif 113 114 /******************************** 115 * Buffer administration routines: 116 * sl_alloc_bufs() 117 * sl_free_bufs() 118 * sl_realloc_bufs() 119 * 120 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because 121 * sl_realloc_bufs provides strong atomicity and reallocation 122 * on actively running device. 123 *********************************/ 124 125 /* 126 Allocate channel buffers. 127 */ 128 129 static int sl_alloc_bufs(struct slip *sl, int mtu) 130 { 131 int err = -ENOBUFS; 132 unsigned long len; 133 char *rbuff = NULL; 134 char *xbuff = NULL; 135 #ifdef SL_INCLUDE_CSLIP 136 char *cbuff = NULL; 137 struct slcompress *slcomp = NULL; 138 #endif 139 140 /* 141 * Allocate the SLIP frame buffers: 142 * 143 * rbuff Receive buffer. 144 * xbuff Transmit buffer. 145 * cbuff Temporary compression buffer. 146 */ 147 len = mtu * 2; 148 149 /* 150 * allow for arrival of larger UDP packets, even if we say not to 151 * also fixes a bug in which SunOS sends 512-byte packets even with 152 * an MSS of 128 153 */ 154 if (len < 576 * 2) 155 len = 576 * 2; 156 rbuff = kmalloc(len + 4, GFP_KERNEL); 157 if (rbuff == NULL) 158 goto err_exit; 159 xbuff = kmalloc(len + 4, GFP_KERNEL); 160 if (xbuff == NULL) 161 goto err_exit; 162 #ifdef SL_INCLUDE_CSLIP 163 cbuff = kmalloc(len + 4, GFP_KERNEL); 164 if (cbuff == NULL) 165 goto err_exit; 166 slcomp = slhc_init(16, 16); 167 if (IS_ERR(slcomp)) 168 goto err_exit; 169 #endif 170 spin_lock_bh(&sl->lock); 171 if (sl->tty == NULL) { 172 spin_unlock_bh(&sl->lock); 173 err = -ENODEV; 174 goto err_exit; 175 } 176 sl->mtu = mtu; 177 sl->buffsize = len; 178 sl->rcount = 0; 179 sl->xleft = 0; 180 rbuff = xchg(&sl->rbuff, rbuff); 181 xbuff = xchg(&sl->xbuff, xbuff); 182 #ifdef SL_INCLUDE_CSLIP 183 cbuff = xchg(&sl->cbuff, cbuff); 184 slcomp = xchg(&sl->slcomp, slcomp); 185 #endif 186 #ifdef CONFIG_SLIP_MODE_SLIP6 187 sl->xdata = 0; 188 sl->xbits = 0; 189 #endif 190 spin_unlock_bh(&sl->lock); 191 err = 0; 192 193 /* Cleanup */ 194 err_exit: 195 #ifdef SL_INCLUDE_CSLIP 196 kfree(cbuff); 197 slhc_free(slcomp); 198 #endif 199 kfree(xbuff); 200 kfree(rbuff); 201 return err; 202 } 203 204 /* Free a SLIP channel buffers. */ 205 static void sl_free_bufs(struct slip *sl) 206 { 207 /* Free all SLIP frame buffers. */ 208 kfree(xchg(&sl->rbuff, NULL)); 209 kfree(xchg(&sl->xbuff, NULL)); 210 #ifdef SL_INCLUDE_CSLIP 211 kfree(xchg(&sl->cbuff, NULL)); 212 slhc_free(xchg(&sl->slcomp, NULL)); 213 #endif 214 } 215 216 /* 217 Reallocate slip channel buffers. 218 */ 219 220 static int sl_realloc_bufs(struct slip *sl, int mtu) 221 { 222 int err = 0; 223 struct net_device *dev = sl->dev; 224 unsigned char *xbuff, *rbuff; 225 #ifdef SL_INCLUDE_CSLIP 226 unsigned char *cbuff; 227 #endif 228 int len = mtu * 2; 229 230 /* 231 * allow for arrival of larger UDP packets, even if we say not to 232 * also fixes a bug in which SunOS sends 512-byte packets even with 233 * an MSS of 128 234 */ 235 if (len < 576 * 2) 236 len = 576 * 2; 237 238 xbuff = kmalloc(len + 4, GFP_ATOMIC); 239 rbuff = kmalloc(len + 4, GFP_ATOMIC); 240 #ifdef SL_INCLUDE_CSLIP 241 cbuff = kmalloc(len + 4, GFP_ATOMIC); 242 #endif 243 244 245 #ifdef SL_INCLUDE_CSLIP 246 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) { 247 #else 248 if (xbuff == NULL || rbuff == NULL) { 249 #endif 250 if (mtu > sl->mtu) { 251 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n", 252 dev->name); 253 err = -ENOBUFS; 254 } 255 goto done; 256 } 257 spin_lock_bh(&sl->lock); 258 259 err = -ENODEV; 260 if (sl->tty == NULL) 261 goto done_on_bh; 262 263 xbuff = xchg(&sl->xbuff, xbuff); 264 rbuff = xchg(&sl->rbuff, rbuff); 265 #ifdef SL_INCLUDE_CSLIP 266 cbuff = xchg(&sl->cbuff, cbuff); 267 #endif 268 if (sl->xleft) { 269 if (sl->xleft <= len) { 270 memcpy(sl->xbuff, sl->xhead, sl->xleft); 271 } else { 272 sl->xleft = 0; 273 dev->stats.tx_dropped++; 274 } 275 } 276 sl->xhead = sl->xbuff; 277 278 if (sl->rcount) { 279 if (sl->rcount <= len) { 280 memcpy(sl->rbuff, rbuff, sl->rcount); 281 } else { 282 sl->rcount = 0; 283 dev->stats.rx_over_errors++; 284 set_bit(SLF_ERROR, &sl->flags); 285 } 286 } 287 sl->mtu = mtu; 288 dev->mtu = mtu; 289 sl->buffsize = len; 290 err = 0; 291 292 done_on_bh: 293 spin_unlock_bh(&sl->lock); 294 295 done: 296 kfree(xbuff); 297 kfree(rbuff); 298 #ifdef SL_INCLUDE_CSLIP 299 kfree(cbuff); 300 #endif 301 return err; 302 } 303 304 305 /* Set the "sending" flag. This must be atomic hence the set_bit. */ 306 static inline void sl_lock(struct slip *sl) 307 { 308 netif_stop_queue(sl->dev); 309 } 310 311 312 /* Clear the "sending" flag. This must be atomic, hence the ASM. */ 313 static inline void sl_unlock(struct slip *sl) 314 { 315 netif_wake_queue(sl->dev); 316 } 317 318 /* Send one completely decapsulated IP datagram to the IP layer. */ 319 static void sl_bump(struct slip *sl) 320 { 321 struct net_device *dev = sl->dev; 322 struct sk_buff *skb; 323 int count; 324 325 count = sl->rcount; 326 #ifdef SL_INCLUDE_CSLIP 327 if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) { 328 unsigned char c = sl->rbuff[0]; 329 if (c & SL_TYPE_COMPRESSED_TCP) { 330 /* ignore compressed packets when CSLIP is off */ 331 if (!(sl->mode & SL_MODE_CSLIP)) { 332 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name); 333 return; 334 } 335 /* make sure we've reserved enough space for uncompress 336 to use */ 337 if (count + 80 > sl->buffsize) { 338 dev->stats.rx_over_errors++; 339 return; 340 } 341 count = slhc_uncompress(sl->slcomp, sl->rbuff, count); 342 if (count <= 0) 343 return; 344 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) { 345 if (!(sl->mode & SL_MODE_CSLIP)) { 346 /* turn on header compression */ 347 sl->mode |= SL_MODE_CSLIP; 348 sl->mode &= ~SL_MODE_ADAPTIVE; 349 printk(KERN_INFO "%s: header compression turned on\n", dev->name); 350 } 351 sl->rbuff[0] &= 0x4f; 352 if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0) 353 return; 354 } 355 } 356 #endif /* SL_INCLUDE_CSLIP */ 357 358 dev->stats.rx_bytes += count; 359 360 skb = dev_alloc_skb(count); 361 if (skb == NULL) { 362 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name); 363 dev->stats.rx_dropped++; 364 return; 365 } 366 skb->dev = dev; 367 memcpy(skb_put(skb, count), sl->rbuff, count); 368 skb_reset_mac_header(skb); 369 skb->protocol = htons(ETH_P_IP); 370 netif_rx_ni(skb); 371 dev->stats.rx_packets++; 372 } 373 374 /* Encapsulate one IP datagram and stuff into a TTY queue. */ 375 static void sl_encaps(struct slip *sl, unsigned char *icp, int len) 376 { 377 unsigned char *p; 378 int actual, count; 379 380 if (len > sl->mtu) { /* Sigh, shouldn't occur BUT ... */ 381 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name); 382 sl->dev->stats.tx_dropped++; 383 sl_unlock(sl); 384 return; 385 } 386 387 p = icp; 388 #ifdef SL_INCLUDE_CSLIP 389 if (sl->mode & SL_MODE_CSLIP) 390 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1); 391 #endif 392 #ifdef CONFIG_SLIP_MODE_SLIP6 393 if (sl->mode & SL_MODE_SLIP6) 394 count = slip_esc6(p, sl->xbuff, len); 395 else 396 #endif 397 count = slip_esc(p, sl->xbuff, len); 398 399 /* Order of next two lines is *very* important. 400 * When we are sending a little amount of data, 401 * the transfer may be completed inside the ops->write() 402 * routine, because it's running with interrupts enabled. 403 * In this case we *never* got WRITE_WAKEUP event, 404 * if we did not request it before write operation. 405 * 14 Oct 1994 Dmitry Gorodchanin. 406 */ 407 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 408 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count); 409 #ifdef SL_CHECK_TRANSMIT 410 netif_trans_update(sl->dev); 411 #endif 412 sl->xleft = count - actual; 413 sl->xhead = sl->xbuff + actual; 414 #ifdef CONFIG_SLIP_SMART 415 /* VSV */ 416 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */ 417 #endif 418 } 419 420 /* Write out any remaining transmit buffer. Scheduled when tty is writable */ 421 static void slip_transmit(struct work_struct *work) 422 { 423 struct slip *sl = container_of(work, struct slip, tx_work); 424 int actual; 425 426 spin_lock_bh(&sl->lock); 427 /* First make sure we're connected. */ 428 if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) { 429 spin_unlock_bh(&sl->lock); 430 return; 431 } 432 433 if (sl->xleft <= 0) { 434 /* Now serial buffer is almost free & we can start 435 * transmission of another packet */ 436 sl->dev->stats.tx_packets++; 437 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 438 spin_unlock_bh(&sl->lock); 439 sl_unlock(sl); 440 return; 441 } 442 443 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft); 444 sl->xleft -= actual; 445 sl->xhead += actual; 446 spin_unlock_bh(&sl->lock); 447 } 448 449 /* 450 * Called by the driver when there's room for more data. 451 * Schedule the transmit. 452 */ 453 static void slip_write_wakeup(struct tty_struct *tty) 454 { 455 struct slip *sl = tty->disc_data; 456 457 schedule_work(&sl->tx_work); 458 } 459 460 static void sl_tx_timeout(struct net_device *dev) 461 { 462 struct slip *sl = netdev_priv(dev); 463 464 spin_lock(&sl->lock); 465 466 if (netif_queue_stopped(dev)) { 467 if (!netif_running(dev)) 468 goto out; 469 470 /* May be we must check transmitter timeout here ? 471 * 14 Oct 1994 Dmitry Gorodchanin. 472 */ 473 #ifdef SL_CHECK_TRANSMIT 474 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) { 475 /* 20 sec timeout not reached */ 476 goto out; 477 } 478 printk(KERN_WARNING "%s: transmit timed out, %s?\n", 479 dev->name, 480 (tty_chars_in_buffer(sl->tty) || sl->xleft) ? 481 "bad line quality" : "driver error"); 482 sl->xleft = 0; 483 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 484 sl_unlock(sl); 485 #endif 486 } 487 out: 488 spin_unlock(&sl->lock); 489 } 490 491 492 /* Encapsulate an IP datagram and kick it into a TTY queue. */ 493 static netdev_tx_t 494 sl_xmit(struct sk_buff *skb, struct net_device *dev) 495 { 496 struct slip *sl = netdev_priv(dev); 497 498 spin_lock(&sl->lock); 499 if (!netif_running(dev)) { 500 spin_unlock(&sl->lock); 501 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name); 502 dev_kfree_skb(skb); 503 return NETDEV_TX_OK; 504 } 505 if (sl->tty == NULL) { 506 spin_unlock(&sl->lock); 507 dev_kfree_skb(skb); 508 return NETDEV_TX_OK; 509 } 510 511 sl_lock(sl); 512 dev->stats.tx_bytes += skb->len; 513 sl_encaps(sl, skb->data, skb->len); 514 spin_unlock(&sl->lock); 515 516 dev_kfree_skb(skb); 517 return NETDEV_TX_OK; 518 } 519 520 521 /****************************************** 522 * Routines looking at netdevice side. 523 ******************************************/ 524 525 /* Netdevice UP -> DOWN routine */ 526 527 static int 528 sl_close(struct net_device *dev) 529 { 530 struct slip *sl = netdev_priv(dev); 531 532 spin_lock_bh(&sl->lock); 533 if (sl->tty) 534 /* TTY discipline is running. */ 535 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 536 netif_stop_queue(dev); 537 sl->rcount = 0; 538 sl->xleft = 0; 539 spin_unlock_bh(&sl->lock); 540 541 return 0; 542 } 543 544 /* Netdevice DOWN -> UP routine */ 545 546 static int sl_open(struct net_device *dev) 547 { 548 struct slip *sl = netdev_priv(dev); 549 550 if (sl->tty == NULL) 551 return -ENODEV; 552 553 sl->flags &= (1 << SLF_INUSE); 554 netif_start_queue(dev); 555 return 0; 556 } 557 558 /* Netdevice change MTU request */ 559 560 static int sl_change_mtu(struct net_device *dev, int new_mtu) 561 { 562 struct slip *sl = netdev_priv(dev); 563 564 return sl_realloc_bufs(sl, new_mtu); 565 } 566 567 /* Netdevice get statistics request */ 568 569 static void 570 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 571 { 572 struct net_device_stats *devstats = &dev->stats; 573 #ifdef SL_INCLUDE_CSLIP 574 struct slip *sl = netdev_priv(dev); 575 struct slcompress *comp = sl->slcomp; 576 #endif 577 stats->rx_packets = devstats->rx_packets; 578 stats->tx_packets = devstats->tx_packets; 579 stats->rx_bytes = devstats->rx_bytes; 580 stats->tx_bytes = devstats->tx_bytes; 581 stats->rx_dropped = devstats->rx_dropped; 582 stats->tx_dropped = devstats->tx_dropped; 583 stats->tx_errors = devstats->tx_errors; 584 stats->rx_errors = devstats->rx_errors; 585 stats->rx_over_errors = devstats->rx_over_errors; 586 587 #ifdef SL_INCLUDE_CSLIP 588 if (comp) { 589 /* Generic compressed statistics */ 590 stats->rx_compressed = comp->sls_i_compressed; 591 stats->tx_compressed = comp->sls_o_compressed; 592 593 /* Are we really still needs this? */ 594 stats->rx_fifo_errors += comp->sls_i_compressed; 595 stats->rx_dropped += comp->sls_i_tossed; 596 stats->tx_fifo_errors += comp->sls_o_compressed; 597 stats->collisions += comp->sls_o_misses; 598 } 599 #endif 600 } 601 602 /* Netdevice register callback */ 603 604 static int sl_init(struct net_device *dev) 605 { 606 struct slip *sl = netdev_priv(dev); 607 608 /* 609 * Finish setting up the DEVICE info. 610 */ 611 612 dev->mtu = sl->mtu; 613 dev->type = ARPHRD_SLIP + sl->mode; 614 #ifdef SL_CHECK_TRANSMIT 615 dev->watchdog_timeo = 20*HZ; 616 #endif 617 return 0; 618 } 619 620 621 static void sl_uninit(struct net_device *dev) 622 { 623 struct slip *sl = netdev_priv(dev); 624 625 sl_free_bufs(sl); 626 } 627 628 /* Hook the destructor so we can free slip devices at the right point in time */ 629 static void sl_free_netdev(struct net_device *dev) 630 { 631 int i = dev->base_addr; 632 free_netdev(dev); 633 slip_devs[i] = NULL; 634 } 635 636 static const struct net_device_ops sl_netdev_ops = { 637 .ndo_init = sl_init, 638 .ndo_uninit = sl_uninit, 639 .ndo_open = sl_open, 640 .ndo_stop = sl_close, 641 .ndo_start_xmit = sl_xmit, 642 .ndo_get_stats64 = sl_get_stats64, 643 .ndo_change_mtu = sl_change_mtu, 644 .ndo_tx_timeout = sl_tx_timeout, 645 #ifdef CONFIG_SLIP_SMART 646 .ndo_do_ioctl = sl_ioctl, 647 #endif 648 }; 649 650 651 static void sl_setup(struct net_device *dev) 652 { 653 dev->netdev_ops = &sl_netdev_ops; 654 dev->destructor = sl_free_netdev; 655 656 dev->hard_header_len = 0; 657 dev->addr_len = 0; 658 dev->tx_queue_len = 10; 659 660 /* MTU range: 68 - 65534 */ 661 dev->min_mtu = 68; 662 dev->max_mtu = 65534; 663 664 /* New-style flags. */ 665 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 666 } 667 668 /****************************************** 669 Routines looking at TTY side. 670 ******************************************/ 671 672 673 /* 674 * Handle the 'receiver data ready' interrupt. 675 * This function is called by the 'tty_io' module in the kernel when 676 * a block of SLIP data has been received, which can now be decapsulated 677 * and sent on to some IP layer for further processing. This will not 678 * be re-entered while running but other ldisc functions may be called 679 * in parallel 680 */ 681 682 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 683 char *fp, int count) 684 { 685 struct slip *sl = tty->disc_data; 686 687 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 688 return; 689 690 /* Read the characters out of the buffer */ 691 while (count--) { 692 if (fp && *fp++) { 693 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 694 sl->dev->stats.rx_errors++; 695 cp++; 696 continue; 697 } 698 #ifdef CONFIG_SLIP_MODE_SLIP6 699 if (sl->mode & SL_MODE_SLIP6) 700 slip_unesc6(sl, *cp++); 701 else 702 #endif 703 slip_unesc(sl, *cp++); 704 } 705 } 706 707 /************************************ 708 * slip_open helper routines. 709 ************************************/ 710 711 /* Collect hanged up channels */ 712 static void sl_sync(void) 713 { 714 int i; 715 struct net_device *dev; 716 struct slip *sl; 717 718 for (i = 0; i < slip_maxdev; i++) { 719 dev = slip_devs[i]; 720 if (dev == NULL) 721 break; 722 723 sl = netdev_priv(dev); 724 if (sl->tty || sl->leased) 725 continue; 726 if (dev->flags & IFF_UP) 727 dev_close(dev); 728 } 729 } 730 731 732 /* Find a free SLIP channel, and link in this `tty' line. */ 733 static struct slip *sl_alloc(dev_t line) 734 { 735 int i; 736 char name[IFNAMSIZ]; 737 struct net_device *dev = NULL; 738 struct slip *sl; 739 740 for (i = 0; i < slip_maxdev; i++) { 741 dev = slip_devs[i]; 742 if (dev == NULL) 743 break; 744 } 745 /* Sorry, too many, all slots in use */ 746 if (i >= slip_maxdev) 747 return NULL; 748 749 sprintf(name, "sl%d", i); 750 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup); 751 if (!dev) 752 return NULL; 753 754 dev->base_addr = i; 755 sl = netdev_priv(dev); 756 757 /* Initialize channel control data */ 758 sl->magic = SLIP_MAGIC; 759 sl->dev = dev; 760 spin_lock_init(&sl->lock); 761 INIT_WORK(&sl->tx_work, slip_transmit); 762 sl->mode = SL_MODE_DEFAULT; 763 #ifdef CONFIG_SLIP_SMART 764 /* initialize timer_list struct */ 765 init_timer(&sl->keepalive_timer); 766 sl->keepalive_timer.data = (unsigned long)sl; 767 sl->keepalive_timer.function = sl_keepalive; 768 init_timer(&sl->outfill_timer); 769 sl->outfill_timer.data = (unsigned long)sl; 770 sl->outfill_timer.function = sl_outfill; 771 #endif 772 slip_devs[i] = dev; 773 return sl; 774 } 775 776 /* 777 * Open the high-level part of the SLIP channel. 778 * This function is called by the TTY module when the 779 * SLIP line discipline is called for. Because we are 780 * sure the tty line exists, we only have to link it to 781 * a free SLIP channel... 782 * 783 * Called in process context serialized from other ldisc calls. 784 */ 785 786 static int slip_open(struct tty_struct *tty) 787 { 788 struct slip *sl; 789 int err; 790 791 if (!capable(CAP_NET_ADMIN)) 792 return -EPERM; 793 794 if (tty->ops->write == NULL) 795 return -EOPNOTSUPP; 796 797 /* RTnetlink lock is misused here to serialize concurrent 798 opens of slip channels. There are better ways, but it is 799 the simplest one. 800 */ 801 rtnl_lock(); 802 803 /* Collect hanged up channels. */ 804 sl_sync(); 805 806 sl = tty->disc_data; 807 808 err = -EEXIST; 809 /* First make sure we're not already connected. */ 810 if (sl && sl->magic == SLIP_MAGIC) 811 goto err_exit; 812 813 /* OK. Find a free SLIP channel to use. */ 814 err = -ENFILE; 815 sl = sl_alloc(tty_devnum(tty)); 816 if (sl == NULL) 817 goto err_exit; 818 819 sl->tty = tty; 820 tty->disc_data = sl; 821 sl->pid = current->pid; 822 823 if (!test_bit(SLF_INUSE, &sl->flags)) { 824 /* Perform the low-level SLIP initialization. */ 825 err = sl_alloc_bufs(sl, SL_MTU); 826 if (err) 827 goto err_free_chan; 828 829 set_bit(SLF_INUSE, &sl->flags); 830 831 err = register_netdevice(sl->dev); 832 if (err) 833 goto err_free_bufs; 834 } 835 836 #ifdef CONFIG_SLIP_SMART 837 if (sl->keepalive) { 838 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 839 add_timer(&sl->keepalive_timer); 840 } 841 if (sl->outfill) { 842 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 843 add_timer(&sl->outfill_timer); 844 } 845 #endif 846 847 /* Done. We have linked the TTY line to a channel. */ 848 rtnl_unlock(); 849 tty->receive_room = 65536; /* We don't flow control */ 850 851 /* TTY layer expects 0 on success */ 852 return 0; 853 854 err_free_bufs: 855 sl_free_bufs(sl); 856 857 err_free_chan: 858 sl->tty = NULL; 859 tty->disc_data = NULL; 860 clear_bit(SLF_INUSE, &sl->flags); 861 862 err_exit: 863 rtnl_unlock(); 864 865 /* Count references from TTY module */ 866 return err; 867 } 868 869 /* 870 * Close down a SLIP channel. 871 * This means flushing out any pending queues, and then returning. This 872 * call is serialized against other ldisc functions. 873 * 874 * We also use this method fo a hangup event 875 */ 876 877 static void slip_close(struct tty_struct *tty) 878 { 879 struct slip *sl = tty->disc_data; 880 881 /* First make sure we're connected. */ 882 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 883 return; 884 885 spin_lock_bh(&sl->lock); 886 tty->disc_data = NULL; 887 sl->tty = NULL; 888 spin_unlock_bh(&sl->lock); 889 890 flush_work(&sl->tx_work); 891 892 /* VSV = very important to remove timers */ 893 #ifdef CONFIG_SLIP_SMART 894 del_timer_sync(&sl->keepalive_timer); 895 del_timer_sync(&sl->outfill_timer); 896 #endif 897 /* Flush network side */ 898 unregister_netdev(sl->dev); 899 /* This will complete via sl_free_netdev */ 900 } 901 902 static int slip_hangup(struct tty_struct *tty) 903 { 904 slip_close(tty); 905 return 0; 906 } 907 /************************************************************************ 908 * STANDARD SLIP ENCAPSULATION * 909 ************************************************************************/ 910 911 static int slip_esc(unsigned char *s, unsigned char *d, int len) 912 { 913 unsigned char *ptr = d; 914 unsigned char c; 915 916 /* 917 * Send an initial END character to flush out any 918 * data that may have accumulated in the receiver 919 * due to line noise. 920 */ 921 922 *ptr++ = END; 923 924 /* 925 * For each byte in the packet, send the appropriate 926 * character sequence, according to the SLIP protocol. 927 */ 928 929 while (len-- > 0) { 930 switch (c = *s++) { 931 case END: 932 *ptr++ = ESC; 933 *ptr++ = ESC_END; 934 break; 935 case ESC: 936 *ptr++ = ESC; 937 *ptr++ = ESC_ESC; 938 break; 939 default: 940 *ptr++ = c; 941 break; 942 } 943 } 944 *ptr++ = END; 945 return ptr - d; 946 } 947 948 static void slip_unesc(struct slip *sl, unsigned char s) 949 { 950 951 switch (s) { 952 case END: 953 #ifdef CONFIG_SLIP_SMART 954 /* drop keeptest bit = VSV */ 955 if (test_bit(SLF_KEEPTEST, &sl->flags)) 956 clear_bit(SLF_KEEPTEST, &sl->flags); 957 #endif 958 959 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 960 (sl->rcount > 2)) 961 sl_bump(sl); 962 clear_bit(SLF_ESCAPE, &sl->flags); 963 sl->rcount = 0; 964 return; 965 966 case ESC: 967 set_bit(SLF_ESCAPE, &sl->flags); 968 return; 969 case ESC_ESC: 970 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 971 s = ESC; 972 break; 973 case ESC_END: 974 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 975 s = END; 976 break; 977 } 978 if (!test_bit(SLF_ERROR, &sl->flags)) { 979 if (sl->rcount < sl->buffsize) { 980 sl->rbuff[sl->rcount++] = s; 981 return; 982 } 983 sl->dev->stats.rx_over_errors++; 984 set_bit(SLF_ERROR, &sl->flags); 985 } 986 } 987 988 989 #ifdef CONFIG_SLIP_MODE_SLIP6 990 /************************************************************************ 991 * 6 BIT SLIP ENCAPSULATION * 992 ************************************************************************/ 993 994 static int slip_esc6(unsigned char *s, unsigned char *d, int len) 995 { 996 unsigned char *ptr = d; 997 unsigned char c; 998 int i; 999 unsigned short v = 0; 1000 short bits = 0; 1001 1002 /* 1003 * Send an initial END character to flush out any 1004 * data that may have accumulated in the receiver 1005 * due to line noise. 1006 */ 1007 1008 *ptr++ = 0x70; 1009 1010 /* 1011 * Encode the packet into printable ascii characters 1012 */ 1013 1014 for (i = 0; i < len; ++i) { 1015 v = (v << 8) | s[i]; 1016 bits += 8; 1017 while (bits >= 6) { 1018 bits -= 6; 1019 c = 0x30 + ((v >> bits) & 0x3F); 1020 *ptr++ = c; 1021 } 1022 } 1023 if (bits) { 1024 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1025 *ptr++ = c; 1026 } 1027 *ptr++ = 0x70; 1028 return ptr - d; 1029 } 1030 1031 static void slip_unesc6(struct slip *sl, unsigned char s) 1032 { 1033 unsigned char c; 1034 1035 if (s == 0x70) { 1036 #ifdef CONFIG_SLIP_SMART 1037 /* drop keeptest bit = VSV */ 1038 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1039 clear_bit(SLF_KEEPTEST, &sl->flags); 1040 #endif 1041 1042 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1043 (sl->rcount > 2)) 1044 sl_bump(sl); 1045 sl->rcount = 0; 1046 sl->xbits = 0; 1047 sl->xdata = 0; 1048 } else if (s >= 0x30 && s < 0x70) { 1049 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1050 sl->xbits += 6; 1051 if (sl->xbits >= 8) { 1052 sl->xbits -= 8; 1053 c = (unsigned char)(sl->xdata >> sl->xbits); 1054 if (!test_bit(SLF_ERROR, &sl->flags)) { 1055 if (sl->rcount < sl->buffsize) { 1056 sl->rbuff[sl->rcount++] = c; 1057 return; 1058 } 1059 sl->dev->stats.rx_over_errors++; 1060 set_bit(SLF_ERROR, &sl->flags); 1061 } 1062 } 1063 } 1064 } 1065 #endif /* CONFIG_SLIP_MODE_SLIP6 */ 1066 1067 /* Perform I/O control on an active SLIP channel. */ 1068 static int slip_ioctl(struct tty_struct *tty, struct file *file, 1069 unsigned int cmd, unsigned long arg) 1070 { 1071 struct slip *sl = tty->disc_data; 1072 unsigned int tmp; 1073 int __user *p = (int __user *)arg; 1074 1075 /* First make sure we're connected. */ 1076 if (!sl || sl->magic != SLIP_MAGIC) 1077 return -EINVAL; 1078 1079 switch (cmd) { 1080 case SIOCGIFNAME: 1081 tmp = strlen(sl->dev->name) + 1; 1082 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1083 return -EFAULT; 1084 return 0; 1085 1086 case SIOCGIFENCAP: 1087 if (put_user(sl->mode, p)) 1088 return -EFAULT; 1089 return 0; 1090 1091 case SIOCSIFENCAP: 1092 if (get_user(tmp, p)) 1093 return -EFAULT; 1094 #ifndef SL_INCLUDE_CSLIP 1095 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1096 return -EINVAL; 1097 #else 1098 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1099 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1100 /* return -EINVAL; */ 1101 tmp &= ~SL_MODE_ADAPTIVE; 1102 #endif 1103 #ifndef CONFIG_SLIP_MODE_SLIP6 1104 if (tmp & SL_MODE_SLIP6) 1105 return -EINVAL; 1106 #endif 1107 sl->mode = tmp; 1108 sl->dev->type = ARPHRD_SLIP + sl->mode; 1109 return 0; 1110 1111 case SIOCSIFHWADDR: 1112 return -EINVAL; 1113 1114 #ifdef CONFIG_SLIP_SMART 1115 /* VSV changes start here */ 1116 case SIOCSKEEPALIVE: 1117 if (get_user(tmp, p)) 1118 return -EFAULT; 1119 if (tmp > 255) /* max for unchar */ 1120 return -EINVAL; 1121 1122 spin_lock_bh(&sl->lock); 1123 if (!sl->tty) { 1124 spin_unlock_bh(&sl->lock); 1125 return -ENODEV; 1126 } 1127 sl->keepalive = (u8)tmp; 1128 if (sl->keepalive != 0) { 1129 mod_timer(&sl->keepalive_timer, 1130 jiffies + sl->keepalive * HZ); 1131 set_bit(SLF_KEEPTEST, &sl->flags); 1132 } else 1133 del_timer(&sl->keepalive_timer); 1134 spin_unlock_bh(&sl->lock); 1135 return 0; 1136 1137 case SIOCGKEEPALIVE: 1138 if (put_user(sl->keepalive, p)) 1139 return -EFAULT; 1140 return 0; 1141 1142 case SIOCSOUTFILL: 1143 if (get_user(tmp, p)) 1144 return -EFAULT; 1145 if (tmp > 255) /* max for unchar */ 1146 return -EINVAL; 1147 spin_lock_bh(&sl->lock); 1148 if (!sl->tty) { 1149 spin_unlock_bh(&sl->lock); 1150 return -ENODEV; 1151 } 1152 sl->outfill = (u8)tmp; 1153 if (sl->outfill != 0) { 1154 mod_timer(&sl->outfill_timer, 1155 jiffies + sl->outfill * HZ); 1156 set_bit(SLF_OUTWAIT, &sl->flags); 1157 } else 1158 del_timer(&sl->outfill_timer); 1159 spin_unlock_bh(&sl->lock); 1160 return 0; 1161 1162 case SIOCGOUTFILL: 1163 if (put_user(sl->outfill, p)) 1164 return -EFAULT; 1165 return 0; 1166 /* VSV changes end */ 1167 #endif 1168 default: 1169 return tty_mode_ioctl(tty, file, cmd, arg); 1170 } 1171 } 1172 1173 #ifdef CONFIG_COMPAT 1174 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file, 1175 unsigned int cmd, unsigned long arg) 1176 { 1177 switch (cmd) { 1178 case SIOCGIFNAME: 1179 case SIOCGIFENCAP: 1180 case SIOCSIFENCAP: 1181 case SIOCSIFHWADDR: 1182 case SIOCSKEEPALIVE: 1183 case SIOCGKEEPALIVE: 1184 case SIOCSOUTFILL: 1185 case SIOCGOUTFILL: 1186 return slip_ioctl(tty, file, cmd, 1187 (unsigned long)compat_ptr(arg)); 1188 } 1189 1190 return -ENOIOCTLCMD; 1191 } 1192 #endif 1193 1194 /* VSV changes start here */ 1195 #ifdef CONFIG_SLIP_SMART 1196 /* function do_ioctl called from net/core/dev.c 1197 to allow get/set outfill/keepalive parameter 1198 by ifconfig */ 1199 1200 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1201 { 1202 struct slip *sl = netdev_priv(dev); 1203 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1204 1205 if (sl == NULL) /* Allocation failed ?? */ 1206 return -ENODEV; 1207 1208 spin_lock_bh(&sl->lock); 1209 1210 if (!sl->tty) { 1211 spin_unlock_bh(&sl->lock); 1212 return -ENODEV; 1213 } 1214 1215 switch (cmd) { 1216 case SIOCSKEEPALIVE: 1217 /* max for unchar */ 1218 if ((unsigned)*p > 255) { 1219 spin_unlock_bh(&sl->lock); 1220 return -EINVAL; 1221 } 1222 sl->keepalive = (u8)*p; 1223 if (sl->keepalive != 0) { 1224 sl->keepalive_timer.expires = 1225 jiffies + sl->keepalive * HZ; 1226 mod_timer(&sl->keepalive_timer, 1227 jiffies + sl->keepalive * HZ); 1228 set_bit(SLF_KEEPTEST, &sl->flags); 1229 } else 1230 del_timer(&sl->keepalive_timer); 1231 break; 1232 1233 case SIOCGKEEPALIVE: 1234 *p = sl->keepalive; 1235 break; 1236 1237 case SIOCSOUTFILL: 1238 if ((unsigned)*p > 255) { /* max for unchar */ 1239 spin_unlock_bh(&sl->lock); 1240 return -EINVAL; 1241 } 1242 sl->outfill = (u8)*p; 1243 if (sl->outfill != 0) { 1244 mod_timer(&sl->outfill_timer, 1245 jiffies + sl->outfill * HZ); 1246 set_bit(SLF_OUTWAIT, &sl->flags); 1247 } else 1248 del_timer(&sl->outfill_timer); 1249 break; 1250 1251 case SIOCGOUTFILL: 1252 *p = sl->outfill; 1253 break; 1254 1255 case SIOCSLEASE: 1256 /* Resolve race condition, when ioctl'ing hanged up 1257 and opened by another process device. 1258 */ 1259 if (sl->tty != current->signal->tty && 1260 sl->pid != current->pid) { 1261 spin_unlock_bh(&sl->lock); 1262 return -EPERM; 1263 } 1264 sl->leased = 0; 1265 if (*p) 1266 sl->leased = 1; 1267 break; 1268 1269 case SIOCGLEASE: 1270 *p = sl->leased; 1271 } 1272 spin_unlock_bh(&sl->lock); 1273 return 0; 1274 } 1275 #endif 1276 /* VSV changes end */ 1277 1278 static struct tty_ldisc_ops sl_ldisc = { 1279 .owner = THIS_MODULE, 1280 .magic = TTY_LDISC_MAGIC, 1281 .name = "slip", 1282 .open = slip_open, 1283 .close = slip_close, 1284 .hangup = slip_hangup, 1285 .ioctl = slip_ioctl, 1286 #ifdef CONFIG_COMPAT 1287 .compat_ioctl = slip_compat_ioctl, 1288 #endif 1289 .receive_buf = slip_receive_buf, 1290 .write_wakeup = slip_write_wakeup, 1291 }; 1292 1293 static int __init slip_init(void) 1294 { 1295 int status; 1296 1297 if (slip_maxdev < 4) 1298 slip_maxdev = 4; /* Sanity */ 1299 1300 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" 1301 #ifdef CONFIG_SLIP_MODE_SLIP6 1302 " (6 bit encapsulation enabled)" 1303 #endif 1304 ".\n", 1305 SLIP_VERSION, slip_maxdev); 1306 #if defined(SL_INCLUDE_CSLIP) 1307 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); 1308 #endif 1309 #ifdef CONFIG_SLIP_SMART 1310 printk(KERN_INFO "SLIP linefill/keepalive option.\n"); 1311 #endif 1312 1313 slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev, 1314 GFP_KERNEL); 1315 if (!slip_devs) 1316 return -ENOMEM; 1317 1318 /* Fill in our line protocol discipline, and register it */ 1319 status = tty_register_ldisc(N_SLIP, &sl_ldisc); 1320 if (status != 0) { 1321 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); 1322 kfree(slip_devs); 1323 } 1324 return status; 1325 } 1326 1327 static void __exit slip_exit(void) 1328 { 1329 int i; 1330 struct net_device *dev; 1331 struct slip *sl; 1332 unsigned long timeout = jiffies + HZ; 1333 int busy = 0; 1334 1335 if (slip_devs == NULL) 1336 return; 1337 1338 /* First of all: check for active disciplines and hangup them. 1339 */ 1340 do { 1341 if (busy) 1342 msleep_interruptible(100); 1343 1344 busy = 0; 1345 for (i = 0; i < slip_maxdev; i++) { 1346 dev = slip_devs[i]; 1347 if (!dev) 1348 continue; 1349 sl = netdev_priv(dev); 1350 spin_lock_bh(&sl->lock); 1351 if (sl->tty) { 1352 busy++; 1353 tty_hangup(sl->tty); 1354 } 1355 spin_unlock_bh(&sl->lock); 1356 } 1357 } while (busy && time_before(jiffies, timeout)); 1358 1359 /* FIXME: hangup is async so we should wait when doing this second 1360 phase */ 1361 1362 for (i = 0; i < slip_maxdev; i++) { 1363 dev = slip_devs[i]; 1364 if (!dev) 1365 continue; 1366 slip_devs[i] = NULL; 1367 1368 sl = netdev_priv(dev); 1369 if (sl->tty) { 1370 printk(KERN_ERR "%s: tty discipline still running\n", 1371 dev->name); 1372 /* Intentionally leak the control block. */ 1373 dev->destructor = NULL; 1374 } 1375 1376 unregister_netdev(dev); 1377 } 1378 1379 kfree(slip_devs); 1380 slip_devs = NULL; 1381 1382 i = tty_unregister_ldisc(N_SLIP); 1383 if (i != 0) 1384 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1385 } 1386 1387 module_init(slip_init); 1388 module_exit(slip_exit); 1389 1390 #ifdef CONFIG_SLIP_SMART 1391 /* 1392 * This is start of the code for multislip style line checking 1393 * added by Stanislav Voronyi. All changes before marked VSV 1394 */ 1395 1396 static void sl_outfill(unsigned long sls) 1397 { 1398 struct slip *sl = (struct slip *)sls; 1399 1400 spin_lock(&sl->lock); 1401 1402 if (sl->tty == NULL) 1403 goto out; 1404 1405 if (sl->outfill) { 1406 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1407 /* no packets were transmitted, do outfill */ 1408 #ifdef CONFIG_SLIP_MODE_SLIP6 1409 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1410 #else 1411 unsigned char s = END; 1412 #endif 1413 /* put END into tty queue. Is it right ??? */ 1414 if (!netif_queue_stopped(sl->dev)) { 1415 /* if device busy no outfill */ 1416 sl->tty->ops->write(sl->tty, &s, 1); 1417 } 1418 } else 1419 set_bit(SLF_OUTWAIT, &sl->flags); 1420 1421 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1422 } 1423 out: 1424 spin_unlock(&sl->lock); 1425 } 1426 1427 static void sl_keepalive(unsigned long sls) 1428 { 1429 struct slip *sl = (struct slip *)sls; 1430 1431 spin_lock(&sl->lock); 1432 1433 if (sl->tty == NULL) 1434 goto out; 1435 1436 if (sl->keepalive) { 1437 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1438 /* keepalive still high :(, we must hangup */ 1439 if (sl->outfill) 1440 /* outfill timer must be deleted too */ 1441 (void)del_timer(&sl->outfill_timer); 1442 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1443 /* this must hangup tty & close slip */ 1444 tty_hangup(sl->tty); 1445 /* I think we need not something else */ 1446 goto out; 1447 } else 1448 set_bit(SLF_KEEPTEST, &sl->flags); 1449 1450 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1451 } 1452 out: 1453 spin_unlock(&sl->lock); 1454 } 1455 1456 #endif 1457 MODULE_LICENSE("GPL"); 1458 MODULE_ALIAS_LDISC(N_SLIP); 1459