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(struct timer_list *t); 110 static void sl_outfill(struct timer_list *t); 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 skb_put_data(skb, 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; 632 633 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->needs_free_netdev = true; 655 dev->priv_destructor = sl_free_netdev; 656 657 dev->hard_header_len = 0; 658 dev->addr_len = 0; 659 dev->tx_queue_len = 10; 660 661 /* MTU range: 68 - 65534 */ 662 dev->min_mtu = 68; 663 dev->max_mtu = 65534; 664 665 /* New-style flags. */ 666 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 667 } 668 669 /****************************************** 670 Routines looking at TTY side. 671 ******************************************/ 672 673 674 /* 675 * Handle the 'receiver data ready' interrupt. 676 * This function is called by the 'tty_io' module in the kernel when 677 * a block of SLIP data has been received, which can now be decapsulated 678 * and sent on to some IP layer for further processing. This will not 679 * be re-entered while running but other ldisc functions may be called 680 * in parallel 681 */ 682 683 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 684 char *fp, int count) 685 { 686 struct slip *sl = tty->disc_data; 687 688 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 689 return; 690 691 /* Read the characters out of the buffer */ 692 while (count--) { 693 if (fp && *fp++) { 694 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 695 sl->dev->stats.rx_errors++; 696 cp++; 697 continue; 698 } 699 #ifdef CONFIG_SLIP_MODE_SLIP6 700 if (sl->mode & SL_MODE_SLIP6) 701 slip_unesc6(sl, *cp++); 702 else 703 #endif 704 slip_unesc(sl, *cp++); 705 } 706 } 707 708 /************************************ 709 * slip_open helper routines. 710 ************************************/ 711 712 /* Collect hanged up channels */ 713 static void sl_sync(void) 714 { 715 int i; 716 struct net_device *dev; 717 struct slip *sl; 718 719 for (i = 0; i < slip_maxdev; i++) { 720 dev = slip_devs[i]; 721 if (dev == NULL) 722 break; 723 724 sl = netdev_priv(dev); 725 if (sl->tty || sl->leased) 726 continue; 727 if (dev->flags & IFF_UP) 728 dev_close(dev); 729 } 730 } 731 732 733 /* Find a free SLIP channel, and link in this `tty' line. */ 734 static struct slip *sl_alloc(void) 735 { 736 int i; 737 char name[IFNAMSIZ]; 738 struct net_device *dev = NULL; 739 struct slip *sl; 740 741 for (i = 0; i < slip_maxdev; i++) { 742 dev = slip_devs[i]; 743 if (dev == NULL) 744 break; 745 } 746 /* Sorry, too many, all slots in use */ 747 if (i >= slip_maxdev) 748 return NULL; 749 750 sprintf(name, "sl%d", i); 751 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup); 752 if (!dev) 753 return NULL; 754 755 dev->base_addr = i; 756 sl = netdev_priv(dev); 757 758 /* Initialize channel control data */ 759 sl->magic = SLIP_MAGIC; 760 sl->dev = dev; 761 spin_lock_init(&sl->lock); 762 INIT_WORK(&sl->tx_work, slip_transmit); 763 sl->mode = SL_MODE_DEFAULT; 764 #ifdef CONFIG_SLIP_SMART 765 /* initialize timer_list struct */ 766 timer_setup(&sl->keepalive_timer, sl_keepalive, 0); 767 timer_setup(&sl->outfill_timer, sl_outfill, 0); 768 #endif 769 slip_devs[i] = dev; 770 return sl; 771 } 772 773 /* 774 * Open the high-level part of the SLIP channel. 775 * This function is called by the TTY module when the 776 * SLIP line discipline is called for. Because we are 777 * sure the tty line exists, we only have to link it to 778 * a free SLIP channel... 779 * 780 * Called in process context serialized from other ldisc calls. 781 */ 782 783 static int slip_open(struct tty_struct *tty) 784 { 785 struct slip *sl; 786 int err; 787 788 if (!capable(CAP_NET_ADMIN)) 789 return -EPERM; 790 791 if (tty->ops->write == NULL) 792 return -EOPNOTSUPP; 793 794 /* RTnetlink lock is misused here to serialize concurrent 795 opens of slip channels. There are better ways, but it is 796 the simplest one. 797 */ 798 rtnl_lock(); 799 800 /* Collect hanged up channels. */ 801 sl_sync(); 802 803 sl = tty->disc_data; 804 805 err = -EEXIST; 806 /* First make sure we're not already connected. */ 807 if (sl && sl->magic == SLIP_MAGIC) 808 goto err_exit; 809 810 /* OK. Find a free SLIP channel to use. */ 811 err = -ENFILE; 812 sl = sl_alloc(); 813 if (sl == NULL) 814 goto err_exit; 815 816 sl->tty = tty; 817 tty->disc_data = sl; 818 sl->pid = current->pid; 819 820 if (!test_bit(SLF_INUSE, &sl->flags)) { 821 /* Perform the low-level SLIP initialization. */ 822 err = sl_alloc_bufs(sl, SL_MTU); 823 if (err) 824 goto err_free_chan; 825 826 set_bit(SLF_INUSE, &sl->flags); 827 828 err = register_netdevice(sl->dev); 829 if (err) 830 goto err_free_bufs; 831 } 832 833 #ifdef CONFIG_SLIP_SMART 834 if (sl->keepalive) { 835 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 836 add_timer(&sl->keepalive_timer); 837 } 838 if (sl->outfill) { 839 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 840 add_timer(&sl->outfill_timer); 841 } 842 #endif 843 844 /* Done. We have linked the TTY line to a channel. */ 845 rtnl_unlock(); 846 tty->receive_room = 65536; /* We don't flow control */ 847 848 /* TTY layer expects 0 on success */ 849 return 0; 850 851 err_free_bufs: 852 sl_free_bufs(sl); 853 854 err_free_chan: 855 sl->tty = NULL; 856 tty->disc_data = NULL; 857 clear_bit(SLF_INUSE, &sl->flags); 858 859 err_exit: 860 rtnl_unlock(); 861 862 /* Count references from TTY module */ 863 return err; 864 } 865 866 /* 867 * Close down a SLIP channel. 868 * This means flushing out any pending queues, and then returning. This 869 * call is serialized against other ldisc functions. 870 * 871 * We also use this method fo a hangup event 872 */ 873 874 static void slip_close(struct tty_struct *tty) 875 { 876 struct slip *sl = tty->disc_data; 877 878 /* First make sure we're connected. */ 879 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 880 return; 881 882 spin_lock_bh(&sl->lock); 883 tty->disc_data = NULL; 884 sl->tty = NULL; 885 spin_unlock_bh(&sl->lock); 886 887 flush_work(&sl->tx_work); 888 889 /* VSV = very important to remove timers */ 890 #ifdef CONFIG_SLIP_SMART 891 del_timer_sync(&sl->keepalive_timer); 892 del_timer_sync(&sl->outfill_timer); 893 #endif 894 /* Flush network side */ 895 unregister_netdev(sl->dev); 896 /* This will complete via sl_free_netdev */ 897 } 898 899 static int slip_hangup(struct tty_struct *tty) 900 { 901 slip_close(tty); 902 return 0; 903 } 904 /************************************************************************ 905 * STANDARD SLIP ENCAPSULATION * 906 ************************************************************************/ 907 908 static int slip_esc(unsigned char *s, unsigned char *d, int len) 909 { 910 unsigned char *ptr = d; 911 unsigned char c; 912 913 /* 914 * Send an initial END character to flush out any 915 * data that may have accumulated in the receiver 916 * due to line noise. 917 */ 918 919 *ptr++ = END; 920 921 /* 922 * For each byte in the packet, send the appropriate 923 * character sequence, according to the SLIP protocol. 924 */ 925 926 while (len-- > 0) { 927 switch (c = *s++) { 928 case END: 929 *ptr++ = ESC; 930 *ptr++ = ESC_END; 931 break; 932 case ESC: 933 *ptr++ = ESC; 934 *ptr++ = ESC_ESC; 935 break; 936 default: 937 *ptr++ = c; 938 break; 939 } 940 } 941 *ptr++ = END; 942 return ptr - d; 943 } 944 945 static void slip_unesc(struct slip *sl, unsigned char s) 946 { 947 948 switch (s) { 949 case END: 950 #ifdef CONFIG_SLIP_SMART 951 /* drop keeptest bit = VSV */ 952 if (test_bit(SLF_KEEPTEST, &sl->flags)) 953 clear_bit(SLF_KEEPTEST, &sl->flags); 954 #endif 955 956 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 957 (sl->rcount > 2)) 958 sl_bump(sl); 959 clear_bit(SLF_ESCAPE, &sl->flags); 960 sl->rcount = 0; 961 return; 962 963 case ESC: 964 set_bit(SLF_ESCAPE, &sl->flags); 965 return; 966 case ESC_ESC: 967 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 968 s = ESC; 969 break; 970 case ESC_END: 971 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 972 s = END; 973 break; 974 } 975 if (!test_bit(SLF_ERROR, &sl->flags)) { 976 if (sl->rcount < sl->buffsize) { 977 sl->rbuff[sl->rcount++] = s; 978 return; 979 } 980 sl->dev->stats.rx_over_errors++; 981 set_bit(SLF_ERROR, &sl->flags); 982 } 983 } 984 985 986 #ifdef CONFIG_SLIP_MODE_SLIP6 987 /************************************************************************ 988 * 6 BIT SLIP ENCAPSULATION * 989 ************************************************************************/ 990 991 static int slip_esc6(unsigned char *s, unsigned char *d, int len) 992 { 993 unsigned char *ptr = d; 994 unsigned char c; 995 int i; 996 unsigned short v = 0; 997 short bits = 0; 998 999 /* 1000 * Send an initial END character to flush out any 1001 * data that may have accumulated in the receiver 1002 * due to line noise. 1003 */ 1004 1005 *ptr++ = 0x70; 1006 1007 /* 1008 * Encode the packet into printable ascii characters 1009 */ 1010 1011 for (i = 0; i < len; ++i) { 1012 v = (v << 8) | s[i]; 1013 bits += 8; 1014 while (bits >= 6) { 1015 bits -= 6; 1016 c = 0x30 + ((v >> bits) & 0x3F); 1017 *ptr++ = c; 1018 } 1019 } 1020 if (bits) { 1021 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1022 *ptr++ = c; 1023 } 1024 *ptr++ = 0x70; 1025 return ptr - d; 1026 } 1027 1028 static void slip_unesc6(struct slip *sl, unsigned char s) 1029 { 1030 unsigned char c; 1031 1032 if (s == 0x70) { 1033 #ifdef CONFIG_SLIP_SMART 1034 /* drop keeptest bit = VSV */ 1035 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1036 clear_bit(SLF_KEEPTEST, &sl->flags); 1037 #endif 1038 1039 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1040 (sl->rcount > 2)) 1041 sl_bump(sl); 1042 sl->rcount = 0; 1043 sl->xbits = 0; 1044 sl->xdata = 0; 1045 } else if (s >= 0x30 && s < 0x70) { 1046 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1047 sl->xbits += 6; 1048 if (sl->xbits >= 8) { 1049 sl->xbits -= 8; 1050 c = (unsigned char)(sl->xdata >> sl->xbits); 1051 if (!test_bit(SLF_ERROR, &sl->flags)) { 1052 if (sl->rcount < sl->buffsize) { 1053 sl->rbuff[sl->rcount++] = c; 1054 return; 1055 } 1056 sl->dev->stats.rx_over_errors++; 1057 set_bit(SLF_ERROR, &sl->flags); 1058 } 1059 } 1060 } 1061 } 1062 #endif /* CONFIG_SLIP_MODE_SLIP6 */ 1063 1064 /* Perform I/O control on an active SLIP channel. */ 1065 static int slip_ioctl(struct tty_struct *tty, struct file *file, 1066 unsigned int cmd, unsigned long arg) 1067 { 1068 struct slip *sl = tty->disc_data; 1069 unsigned int tmp; 1070 int __user *p = (int __user *)arg; 1071 1072 /* First make sure we're connected. */ 1073 if (!sl || sl->magic != SLIP_MAGIC) 1074 return -EINVAL; 1075 1076 switch (cmd) { 1077 case SIOCGIFNAME: 1078 tmp = strlen(sl->dev->name) + 1; 1079 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1080 return -EFAULT; 1081 return 0; 1082 1083 case SIOCGIFENCAP: 1084 if (put_user(sl->mode, p)) 1085 return -EFAULT; 1086 return 0; 1087 1088 case SIOCSIFENCAP: 1089 if (get_user(tmp, p)) 1090 return -EFAULT; 1091 #ifndef SL_INCLUDE_CSLIP 1092 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1093 return -EINVAL; 1094 #else 1095 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1096 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1097 /* return -EINVAL; */ 1098 tmp &= ~SL_MODE_ADAPTIVE; 1099 #endif 1100 #ifndef CONFIG_SLIP_MODE_SLIP6 1101 if (tmp & SL_MODE_SLIP6) 1102 return -EINVAL; 1103 #endif 1104 sl->mode = tmp; 1105 sl->dev->type = ARPHRD_SLIP + sl->mode; 1106 return 0; 1107 1108 case SIOCSIFHWADDR: 1109 return -EINVAL; 1110 1111 #ifdef CONFIG_SLIP_SMART 1112 /* VSV changes start here */ 1113 case SIOCSKEEPALIVE: 1114 if (get_user(tmp, p)) 1115 return -EFAULT; 1116 if (tmp > 255) /* max for unchar */ 1117 return -EINVAL; 1118 1119 spin_lock_bh(&sl->lock); 1120 if (!sl->tty) { 1121 spin_unlock_bh(&sl->lock); 1122 return -ENODEV; 1123 } 1124 sl->keepalive = (u8)tmp; 1125 if (sl->keepalive != 0) { 1126 mod_timer(&sl->keepalive_timer, 1127 jiffies + sl->keepalive * HZ); 1128 set_bit(SLF_KEEPTEST, &sl->flags); 1129 } else 1130 del_timer(&sl->keepalive_timer); 1131 spin_unlock_bh(&sl->lock); 1132 return 0; 1133 1134 case SIOCGKEEPALIVE: 1135 if (put_user(sl->keepalive, p)) 1136 return -EFAULT; 1137 return 0; 1138 1139 case SIOCSOUTFILL: 1140 if (get_user(tmp, p)) 1141 return -EFAULT; 1142 if (tmp > 255) /* max for unchar */ 1143 return -EINVAL; 1144 spin_lock_bh(&sl->lock); 1145 if (!sl->tty) { 1146 spin_unlock_bh(&sl->lock); 1147 return -ENODEV; 1148 } 1149 sl->outfill = (u8)tmp; 1150 if (sl->outfill != 0) { 1151 mod_timer(&sl->outfill_timer, 1152 jiffies + sl->outfill * HZ); 1153 set_bit(SLF_OUTWAIT, &sl->flags); 1154 } else 1155 del_timer(&sl->outfill_timer); 1156 spin_unlock_bh(&sl->lock); 1157 return 0; 1158 1159 case SIOCGOUTFILL: 1160 if (put_user(sl->outfill, p)) 1161 return -EFAULT; 1162 return 0; 1163 /* VSV changes end */ 1164 #endif 1165 default: 1166 return tty_mode_ioctl(tty, file, cmd, arg); 1167 } 1168 } 1169 1170 #ifdef CONFIG_COMPAT 1171 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file, 1172 unsigned int cmd, unsigned long arg) 1173 { 1174 switch (cmd) { 1175 case SIOCGIFNAME: 1176 case SIOCGIFENCAP: 1177 case SIOCSIFENCAP: 1178 case SIOCSIFHWADDR: 1179 case SIOCSKEEPALIVE: 1180 case SIOCGKEEPALIVE: 1181 case SIOCSOUTFILL: 1182 case SIOCGOUTFILL: 1183 return slip_ioctl(tty, file, cmd, 1184 (unsigned long)compat_ptr(arg)); 1185 } 1186 1187 return -ENOIOCTLCMD; 1188 } 1189 #endif 1190 1191 /* VSV changes start here */ 1192 #ifdef CONFIG_SLIP_SMART 1193 /* function do_ioctl called from net/core/dev.c 1194 to allow get/set outfill/keepalive parameter 1195 by ifconfig */ 1196 1197 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1198 { 1199 struct slip *sl = netdev_priv(dev); 1200 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1201 1202 if (sl == NULL) /* Allocation failed ?? */ 1203 return -ENODEV; 1204 1205 spin_lock_bh(&sl->lock); 1206 1207 if (!sl->tty) { 1208 spin_unlock_bh(&sl->lock); 1209 return -ENODEV; 1210 } 1211 1212 switch (cmd) { 1213 case SIOCSKEEPALIVE: 1214 /* max for unchar */ 1215 if ((unsigned)*p > 255) { 1216 spin_unlock_bh(&sl->lock); 1217 return -EINVAL; 1218 } 1219 sl->keepalive = (u8)*p; 1220 if (sl->keepalive != 0) { 1221 sl->keepalive_timer.expires = 1222 jiffies + sl->keepalive * HZ; 1223 mod_timer(&sl->keepalive_timer, 1224 jiffies + sl->keepalive * HZ); 1225 set_bit(SLF_KEEPTEST, &sl->flags); 1226 } else 1227 del_timer(&sl->keepalive_timer); 1228 break; 1229 1230 case SIOCGKEEPALIVE: 1231 *p = sl->keepalive; 1232 break; 1233 1234 case SIOCSOUTFILL: 1235 if ((unsigned)*p > 255) { /* max for unchar */ 1236 spin_unlock_bh(&sl->lock); 1237 return -EINVAL; 1238 } 1239 sl->outfill = (u8)*p; 1240 if (sl->outfill != 0) { 1241 mod_timer(&sl->outfill_timer, 1242 jiffies + sl->outfill * HZ); 1243 set_bit(SLF_OUTWAIT, &sl->flags); 1244 } else 1245 del_timer(&sl->outfill_timer); 1246 break; 1247 1248 case SIOCGOUTFILL: 1249 *p = sl->outfill; 1250 break; 1251 1252 case SIOCSLEASE: 1253 /* Resolve race condition, when ioctl'ing hanged up 1254 and opened by another process device. 1255 */ 1256 if (sl->tty != current->signal->tty && 1257 sl->pid != current->pid) { 1258 spin_unlock_bh(&sl->lock); 1259 return -EPERM; 1260 } 1261 sl->leased = 0; 1262 if (*p) 1263 sl->leased = 1; 1264 break; 1265 1266 case SIOCGLEASE: 1267 *p = sl->leased; 1268 } 1269 spin_unlock_bh(&sl->lock); 1270 return 0; 1271 } 1272 #endif 1273 /* VSV changes end */ 1274 1275 static struct tty_ldisc_ops sl_ldisc = { 1276 .owner = THIS_MODULE, 1277 .magic = TTY_LDISC_MAGIC, 1278 .name = "slip", 1279 .open = slip_open, 1280 .close = slip_close, 1281 .hangup = slip_hangup, 1282 .ioctl = slip_ioctl, 1283 #ifdef CONFIG_COMPAT 1284 .compat_ioctl = slip_compat_ioctl, 1285 #endif 1286 .receive_buf = slip_receive_buf, 1287 .write_wakeup = slip_write_wakeup, 1288 }; 1289 1290 static int __init slip_init(void) 1291 { 1292 int status; 1293 1294 if (slip_maxdev < 4) 1295 slip_maxdev = 4; /* Sanity */ 1296 1297 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" 1298 #ifdef CONFIG_SLIP_MODE_SLIP6 1299 " (6 bit encapsulation enabled)" 1300 #endif 1301 ".\n", 1302 SLIP_VERSION, slip_maxdev); 1303 #if defined(SL_INCLUDE_CSLIP) 1304 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); 1305 #endif 1306 #ifdef CONFIG_SLIP_SMART 1307 printk(KERN_INFO "SLIP linefill/keepalive option.\n"); 1308 #endif 1309 1310 slip_devs = kcalloc(slip_maxdev, sizeof(struct net_device *), 1311 GFP_KERNEL); 1312 if (!slip_devs) 1313 return -ENOMEM; 1314 1315 /* Fill in our line protocol discipline, and register it */ 1316 status = tty_register_ldisc(N_SLIP, &sl_ldisc); 1317 if (status != 0) { 1318 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); 1319 kfree(slip_devs); 1320 } 1321 return status; 1322 } 1323 1324 static void __exit slip_exit(void) 1325 { 1326 int i; 1327 struct net_device *dev; 1328 struct slip *sl; 1329 unsigned long timeout = jiffies + HZ; 1330 int busy = 0; 1331 1332 if (slip_devs == NULL) 1333 return; 1334 1335 /* First of all: check for active disciplines and hangup them. 1336 */ 1337 do { 1338 if (busy) 1339 msleep_interruptible(100); 1340 1341 busy = 0; 1342 for (i = 0; i < slip_maxdev; i++) { 1343 dev = slip_devs[i]; 1344 if (!dev) 1345 continue; 1346 sl = netdev_priv(dev); 1347 spin_lock_bh(&sl->lock); 1348 if (sl->tty) { 1349 busy++; 1350 tty_hangup(sl->tty); 1351 } 1352 spin_unlock_bh(&sl->lock); 1353 } 1354 } while (busy && time_before(jiffies, timeout)); 1355 1356 /* FIXME: hangup is async so we should wait when doing this second 1357 phase */ 1358 1359 for (i = 0; i < slip_maxdev; i++) { 1360 dev = slip_devs[i]; 1361 if (!dev) 1362 continue; 1363 slip_devs[i] = NULL; 1364 1365 sl = netdev_priv(dev); 1366 if (sl->tty) { 1367 printk(KERN_ERR "%s: tty discipline still running\n", 1368 dev->name); 1369 } 1370 1371 unregister_netdev(dev); 1372 } 1373 1374 kfree(slip_devs); 1375 slip_devs = NULL; 1376 1377 i = tty_unregister_ldisc(N_SLIP); 1378 if (i != 0) 1379 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1380 } 1381 1382 module_init(slip_init); 1383 module_exit(slip_exit); 1384 1385 #ifdef CONFIG_SLIP_SMART 1386 /* 1387 * This is start of the code for multislip style line checking 1388 * added by Stanislav Voronyi. All changes before marked VSV 1389 */ 1390 1391 static void sl_outfill(struct timer_list *t) 1392 { 1393 struct slip *sl = from_timer(sl, t, outfill_timer); 1394 1395 spin_lock(&sl->lock); 1396 1397 if (sl->tty == NULL) 1398 goto out; 1399 1400 if (sl->outfill) { 1401 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1402 /* no packets were transmitted, do outfill */ 1403 #ifdef CONFIG_SLIP_MODE_SLIP6 1404 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1405 #else 1406 unsigned char s = END; 1407 #endif 1408 /* put END into tty queue. Is it right ??? */ 1409 if (!netif_queue_stopped(sl->dev)) { 1410 /* if device busy no outfill */ 1411 sl->tty->ops->write(sl->tty, &s, 1); 1412 } 1413 } else 1414 set_bit(SLF_OUTWAIT, &sl->flags); 1415 1416 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1417 } 1418 out: 1419 spin_unlock(&sl->lock); 1420 } 1421 1422 static void sl_keepalive(struct timer_list *t) 1423 { 1424 struct slip *sl = from_timer(sl, t, keepalive_timer); 1425 1426 spin_lock(&sl->lock); 1427 1428 if (sl->tty == NULL) 1429 goto out; 1430 1431 if (sl->keepalive) { 1432 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1433 /* keepalive still high :(, we must hangup */ 1434 if (sl->outfill) 1435 /* outfill timer must be deleted too */ 1436 (void)del_timer(&sl->outfill_timer); 1437 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1438 /* this must hangup tty & close slip */ 1439 tty_hangup(sl->tty); 1440 /* I think we need not something else */ 1441 goto out; 1442 } else 1443 set_bit(SLF_KEEPTEST, &sl->flags); 1444 1445 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1446 } 1447 out: 1448 spin_unlock(&sl->lock); 1449 } 1450 1451 #endif 1452 MODULE_LICENSE("GPL"); 1453 MODULE_ALIAS_LDISC(N_SLIP); 1454