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 <asm/uaccess.h> 68#include <linux/bitops.h> 69#include <linux/sched.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 96static struct net_device **slip_devs; 97 98static int slip_maxdev = SL_NRUNIT; 99module_param(slip_maxdev, int, 0); 100MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices"); 101 102static int slip_esc(unsigned char *p, unsigned char *d, int len); 103static void slip_unesc(struct slip *sl, unsigned char c); 104#ifdef CONFIG_SLIP_MODE_SLIP6 105static int slip_esc6(unsigned char *p, unsigned char *d, int len); 106static void slip_unesc6(struct slip *sl, unsigned char c); 107#endif 108#ifdef CONFIG_SLIP_SMART 109static void sl_keepalive(unsigned long sls); 110static void sl_outfill(unsigned long sls); 111static 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 129static 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 */ 194err_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. */ 205static 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 220static 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 292done_on_bh: 293 spin_unlock_bh(&sl->lock); 294 295done: 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. */ 306static 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. */ 313static 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. */ 319static 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. */ 375static 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 sl->dev->trans_start = jiffies; 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 */ 421static 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 */ 453static 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 460static 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 } 487out: 488 spin_unlock(&sl->lock); 489} 490 491 492/* Encapsulate an IP datagram and kick it into a TTY queue. */ 493static netdev_tx_t 494sl_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 527static int 528sl_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 546static 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 560static int sl_change_mtu(struct net_device *dev, int new_mtu) 561{ 562 struct slip *sl = netdev_priv(dev); 563 564 if (new_mtu < 68 || new_mtu > 65534) 565 return -EINVAL; 566 567 if (new_mtu != dev->mtu) 568 return sl_realloc_bufs(sl, new_mtu); 569 return 0; 570} 571 572/* Netdevice get statistics request */ 573 574static struct rtnl_link_stats64 * 575sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 576{ 577 struct net_device_stats *devstats = &dev->stats; 578#ifdef SL_INCLUDE_CSLIP 579 struct slip *sl = netdev_priv(dev); 580 struct slcompress *comp = sl->slcomp; 581#endif 582 stats->rx_packets = devstats->rx_packets; 583 stats->tx_packets = devstats->tx_packets; 584 stats->rx_bytes = devstats->rx_bytes; 585 stats->tx_bytes = devstats->tx_bytes; 586 stats->rx_dropped = devstats->rx_dropped; 587 stats->tx_dropped = devstats->tx_dropped; 588 stats->tx_errors = devstats->tx_errors; 589 stats->rx_errors = devstats->rx_errors; 590 stats->rx_over_errors = devstats->rx_over_errors; 591 592#ifdef SL_INCLUDE_CSLIP 593 if (comp) { 594 /* Generic compressed statistics */ 595 stats->rx_compressed = comp->sls_i_compressed; 596 stats->tx_compressed = comp->sls_o_compressed; 597 598 /* Are we really still needs this? */ 599 stats->rx_fifo_errors += comp->sls_i_compressed; 600 stats->rx_dropped += comp->sls_i_tossed; 601 stats->tx_fifo_errors += comp->sls_o_compressed; 602 stats->collisions += comp->sls_o_misses; 603 } 604#endif 605 return stats; 606} 607 608/* Netdevice register callback */ 609 610static int sl_init(struct net_device *dev) 611{ 612 struct slip *sl = netdev_priv(dev); 613 614 /* 615 * Finish setting up the DEVICE info. 616 */ 617 618 dev->mtu = sl->mtu; 619 dev->type = ARPHRD_SLIP + sl->mode; 620#ifdef SL_CHECK_TRANSMIT 621 dev->watchdog_timeo = 20*HZ; 622#endif 623 return 0; 624} 625 626 627static void sl_uninit(struct net_device *dev) 628{ 629 struct slip *sl = netdev_priv(dev); 630 631 sl_free_bufs(sl); 632} 633 634/* Hook the destructor so we can free slip devices at the right point in time */ 635static void sl_free_netdev(struct net_device *dev) 636{ 637 int i = dev->base_addr; 638 free_netdev(dev); 639 slip_devs[i] = NULL; 640} 641 642static const struct net_device_ops sl_netdev_ops = { 643 .ndo_init = sl_init, 644 .ndo_uninit = sl_uninit, 645 .ndo_open = sl_open, 646 .ndo_stop = sl_close, 647 .ndo_start_xmit = sl_xmit, 648 .ndo_get_stats64 = sl_get_stats64, 649 .ndo_change_mtu = sl_change_mtu, 650 .ndo_tx_timeout = sl_tx_timeout, 651#ifdef CONFIG_SLIP_SMART 652 .ndo_do_ioctl = sl_ioctl, 653#endif 654}; 655 656 657static void sl_setup(struct net_device *dev) 658{ 659 dev->netdev_ops = &sl_netdev_ops; 660 dev->destructor = sl_free_netdev; 661 662 dev->hard_header_len = 0; 663 dev->addr_len = 0; 664 dev->tx_queue_len = 10; 665 666 /* New-style flags. */ 667 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 668} 669 670/****************************************** 671 Routines looking at TTY side. 672 ******************************************/ 673 674 675/* 676 * Handle the 'receiver data ready' interrupt. 677 * This function is called by the 'tty_io' module in the kernel when 678 * a block of SLIP data has been received, which can now be decapsulated 679 * and sent on to some IP layer for further processing. This will not 680 * be re-entered while running but other ldisc functions may be called 681 * in parallel 682 */ 683 684static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 685 char *fp, int count) 686{ 687 struct slip *sl = tty->disc_data; 688 689 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 690 return; 691 692 /* Read the characters out of the buffer */ 693 while (count--) { 694 if (fp && *fp++) { 695 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 696 sl->dev->stats.rx_errors++; 697 cp++; 698 continue; 699 } 700#ifdef CONFIG_SLIP_MODE_SLIP6 701 if (sl->mode & SL_MODE_SLIP6) 702 slip_unesc6(sl, *cp++); 703 else 704#endif 705 slip_unesc(sl, *cp++); 706 } 707} 708 709/************************************ 710 * slip_open helper routines. 711 ************************************/ 712 713/* Collect hanged up channels */ 714static void sl_sync(void) 715{ 716 int i; 717 struct net_device *dev; 718 struct slip *sl; 719 720 for (i = 0; i < slip_maxdev; i++) { 721 dev = slip_devs[i]; 722 if (dev == NULL) 723 break; 724 725 sl = netdev_priv(dev); 726 if (sl->tty || sl->leased) 727 continue; 728 if (dev->flags & IFF_UP) 729 dev_close(dev); 730 } 731} 732 733 734/* Find a free SLIP channel, and link in this `tty' line. */ 735static struct slip *sl_alloc(dev_t line) 736{ 737 int i; 738 char name[IFNAMSIZ]; 739 struct net_device *dev = NULL; 740 struct slip *sl; 741 742 for (i = 0; i < slip_maxdev; i++) { 743 dev = slip_devs[i]; 744 if (dev == NULL) 745 break; 746 } 747 /* Sorry, too many, all slots in use */ 748 if (i >= slip_maxdev) 749 return NULL; 750 751 sprintf(name, "sl%d", i); 752 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup); 753 if (!dev) 754 return NULL; 755 756 dev->base_addr = i; 757 sl = netdev_priv(dev); 758 759 /* Initialize channel control data */ 760 sl->magic = SLIP_MAGIC; 761 sl->dev = dev; 762 spin_lock_init(&sl->lock); 763 INIT_WORK(&sl->tx_work, slip_transmit); 764 sl->mode = SL_MODE_DEFAULT; 765#ifdef CONFIG_SLIP_SMART 766 /* initialize timer_list struct */ 767 init_timer(&sl->keepalive_timer); 768 sl->keepalive_timer.data = (unsigned long)sl; 769 sl->keepalive_timer.function = sl_keepalive; 770 init_timer(&sl->outfill_timer); 771 sl->outfill_timer.data = (unsigned long)sl; 772 sl->outfill_timer.function = sl_outfill; 773#endif 774 slip_devs[i] = dev; 775 return sl; 776} 777 778/* 779 * Open the high-level part of the SLIP channel. 780 * This function is called by the TTY module when the 781 * SLIP line discipline is called for. Because we are 782 * sure the tty line exists, we only have to link it to 783 * a free SLIP channel... 784 * 785 * Called in process context serialized from other ldisc calls. 786 */ 787 788static int slip_open(struct tty_struct *tty) 789{ 790 struct slip *sl; 791 int err; 792 793 if (!capable(CAP_NET_ADMIN)) 794 return -EPERM; 795 796 if (tty->ops->write == NULL) 797 return -EOPNOTSUPP; 798 799 /* RTnetlink lock is misused here to serialize concurrent 800 opens of slip channels. There are better ways, but it is 801 the simplest one. 802 */ 803 rtnl_lock(); 804 805 /* Collect hanged up channels. */ 806 sl_sync(); 807 808 sl = tty->disc_data; 809 810 err = -EEXIST; 811 /* First make sure we're not already connected. */ 812 if (sl && sl->magic == SLIP_MAGIC) 813 goto err_exit; 814 815 /* OK. Find a free SLIP channel to use. */ 816 err = -ENFILE; 817 sl = sl_alloc(tty_devnum(tty)); 818 if (sl == NULL) 819 goto err_exit; 820 821 sl->tty = tty; 822 tty->disc_data = sl; 823 sl->pid = current->pid; 824 825 if (!test_bit(SLF_INUSE, &sl->flags)) { 826 /* Perform the low-level SLIP initialization. */ 827 err = sl_alloc_bufs(sl, SL_MTU); 828 if (err) 829 goto err_free_chan; 830 831 set_bit(SLF_INUSE, &sl->flags); 832 833 err = register_netdevice(sl->dev); 834 if (err) 835 goto err_free_bufs; 836 } 837 838#ifdef CONFIG_SLIP_SMART 839 if (sl->keepalive) { 840 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 841 add_timer(&sl->keepalive_timer); 842 } 843 if (sl->outfill) { 844 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 845 add_timer(&sl->outfill_timer); 846 } 847#endif 848 849 /* Done. We have linked the TTY line to a channel. */ 850 rtnl_unlock(); 851 tty->receive_room = 65536; /* We don't flow control */ 852 853 /* TTY layer expects 0 on success */ 854 return 0; 855 856err_free_bufs: 857 sl_free_bufs(sl); 858 859err_free_chan: 860 sl->tty = NULL; 861 tty->disc_data = NULL; 862 clear_bit(SLF_INUSE, &sl->flags); 863 864err_exit: 865 rtnl_unlock(); 866 867 /* Count references from TTY module */ 868 return err; 869} 870 871/* 872 * Close down a SLIP channel. 873 * This means flushing out any pending queues, and then returning. This 874 * call is serialized against other ldisc functions. 875 * 876 * We also use this method fo a hangup event 877 */ 878 879static void slip_close(struct tty_struct *tty) 880{ 881 struct slip *sl = tty->disc_data; 882 883 /* First make sure we're connected. */ 884 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 885 return; 886 887 spin_lock_bh(&sl->lock); 888 tty->disc_data = NULL; 889 sl->tty = NULL; 890 spin_unlock_bh(&sl->lock); 891 892 flush_work(&sl->tx_work); 893 894 /* VSV = very important to remove timers */ 895#ifdef CONFIG_SLIP_SMART 896 del_timer_sync(&sl->keepalive_timer); 897 del_timer_sync(&sl->outfill_timer); 898#endif 899 /* Flush network side */ 900 unregister_netdev(sl->dev); 901 /* This will complete via sl_free_netdev */ 902} 903 904static int slip_hangup(struct tty_struct *tty) 905{ 906 slip_close(tty); 907 return 0; 908} 909 /************************************************************************ 910 * STANDARD SLIP ENCAPSULATION * 911 ************************************************************************/ 912 913static int slip_esc(unsigned char *s, unsigned char *d, int len) 914{ 915 unsigned char *ptr = d; 916 unsigned char c; 917 918 /* 919 * Send an initial END character to flush out any 920 * data that may have accumulated in the receiver 921 * due to line noise. 922 */ 923 924 *ptr++ = END; 925 926 /* 927 * For each byte in the packet, send the appropriate 928 * character sequence, according to the SLIP protocol. 929 */ 930 931 while (len-- > 0) { 932 switch (c = *s++) { 933 case END: 934 *ptr++ = ESC; 935 *ptr++ = ESC_END; 936 break; 937 case ESC: 938 *ptr++ = ESC; 939 *ptr++ = ESC_ESC; 940 break; 941 default: 942 *ptr++ = c; 943 break; 944 } 945 } 946 *ptr++ = END; 947 return ptr - d; 948} 949 950static void slip_unesc(struct slip *sl, unsigned char s) 951{ 952 953 switch (s) { 954 case END: 955#ifdef CONFIG_SLIP_SMART 956 /* drop keeptest bit = VSV */ 957 if (test_bit(SLF_KEEPTEST, &sl->flags)) 958 clear_bit(SLF_KEEPTEST, &sl->flags); 959#endif 960 961 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 962 (sl->rcount > 2)) 963 sl_bump(sl); 964 clear_bit(SLF_ESCAPE, &sl->flags); 965 sl->rcount = 0; 966 return; 967 968 case ESC: 969 set_bit(SLF_ESCAPE, &sl->flags); 970 return; 971 case ESC_ESC: 972 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 973 s = ESC; 974 break; 975 case ESC_END: 976 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 977 s = END; 978 break; 979 } 980 if (!test_bit(SLF_ERROR, &sl->flags)) { 981 if (sl->rcount < sl->buffsize) { 982 sl->rbuff[sl->rcount++] = s; 983 return; 984 } 985 sl->dev->stats.rx_over_errors++; 986 set_bit(SLF_ERROR, &sl->flags); 987 } 988} 989 990 991#ifdef CONFIG_SLIP_MODE_SLIP6 992/************************************************************************ 993 * 6 BIT SLIP ENCAPSULATION * 994 ************************************************************************/ 995 996static int slip_esc6(unsigned char *s, unsigned char *d, int len) 997{ 998 unsigned char *ptr = d; 999 unsigned char c; 1000 int i; 1001 unsigned short v = 0; 1002 short bits = 0; 1003 1004 /* 1005 * Send an initial END character to flush out any 1006 * data that may have accumulated in the receiver 1007 * due to line noise. 1008 */ 1009 1010 *ptr++ = 0x70; 1011 1012 /* 1013 * Encode the packet into printable ascii characters 1014 */ 1015 1016 for (i = 0; i < len; ++i) { 1017 v = (v << 8) | s[i]; 1018 bits += 8; 1019 while (bits >= 6) { 1020 bits -= 6; 1021 c = 0x30 + ((v >> bits) & 0x3F); 1022 *ptr++ = c; 1023 } 1024 } 1025 if (bits) { 1026 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1027 *ptr++ = c; 1028 } 1029 *ptr++ = 0x70; 1030 return ptr - d; 1031} 1032 1033static void slip_unesc6(struct slip *sl, unsigned char s) 1034{ 1035 unsigned char c; 1036 1037 if (s == 0x70) { 1038#ifdef CONFIG_SLIP_SMART 1039 /* drop keeptest bit = VSV */ 1040 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1041 clear_bit(SLF_KEEPTEST, &sl->flags); 1042#endif 1043 1044 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1045 (sl->rcount > 2)) 1046 sl_bump(sl); 1047 sl->rcount = 0; 1048 sl->xbits = 0; 1049 sl->xdata = 0; 1050 } else if (s >= 0x30 && s < 0x70) { 1051 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1052 sl->xbits += 6; 1053 if (sl->xbits >= 8) { 1054 sl->xbits -= 8; 1055 c = (unsigned char)(sl->xdata >> sl->xbits); 1056 if (!test_bit(SLF_ERROR, &sl->flags)) { 1057 if (sl->rcount < sl->buffsize) { 1058 sl->rbuff[sl->rcount++] = c; 1059 return; 1060 } 1061 sl->dev->stats.rx_over_errors++; 1062 set_bit(SLF_ERROR, &sl->flags); 1063 } 1064 } 1065 } 1066} 1067#endif /* CONFIG_SLIP_MODE_SLIP6 */ 1068 1069/* Perform I/O control on an active SLIP channel. */ 1070static int slip_ioctl(struct tty_struct *tty, struct file *file, 1071 unsigned int cmd, unsigned long arg) 1072{ 1073 struct slip *sl = tty->disc_data; 1074 unsigned int tmp; 1075 int __user *p = (int __user *)arg; 1076 1077 /* First make sure we're connected. */ 1078 if (!sl || sl->magic != SLIP_MAGIC) 1079 return -EINVAL; 1080 1081 switch (cmd) { 1082 case SIOCGIFNAME: 1083 tmp = strlen(sl->dev->name) + 1; 1084 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1085 return -EFAULT; 1086 return 0; 1087 1088 case SIOCGIFENCAP: 1089 if (put_user(sl->mode, p)) 1090 return -EFAULT; 1091 return 0; 1092 1093 case SIOCSIFENCAP: 1094 if (get_user(tmp, p)) 1095 return -EFAULT; 1096#ifndef SL_INCLUDE_CSLIP 1097 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1098 return -EINVAL; 1099#else 1100 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1101 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1102 /* return -EINVAL; */ 1103 tmp &= ~SL_MODE_ADAPTIVE; 1104#endif 1105#ifndef CONFIG_SLIP_MODE_SLIP6 1106 if (tmp & SL_MODE_SLIP6) 1107 return -EINVAL; 1108#endif 1109 sl->mode = tmp; 1110 sl->dev->type = ARPHRD_SLIP + sl->mode; 1111 return 0; 1112 1113 case SIOCSIFHWADDR: 1114 return -EINVAL; 1115 1116#ifdef CONFIG_SLIP_SMART 1117 /* VSV changes start here */ 1118 case SIOCSKEEPALIVE: 1119 if (get_user(tmp, p)) 1120 return -EFAULT; 1121 if (tmp > 255) /* max for unchar */ 1122 return -EINVAL; 1123 1124 spin_lock_bh(&sl->lock); 1125 if (!sl->tty) { 1126 spin_unlock_bh(&sl->lock); 1127 return -ENODEV; 1128 } 1129 sl->keepalive = (u8)tmp; 1130 if (sl->keepalive != 0) { 1131 mod_timer(&sl->keepalive_timer, 1132 jiffies + sl->keepalive * HZ); 1133 set_bit(SLF_KEEPTEST, &sl->flags); 1134 } else 1135 del_timer(&sl->keepalive_timer); 1136 spin_unlock_bh(&sl->lock); 1137 return 0; 1138 1139 case SIOCGKEEPALIVE: 1140 if (put_user(sl->keepalive, p)) 1141 return -EFAULT; 1142 return 0; 1143 1144 case SIOCSOUTFILL: 1145 if (get_user(tmp, p)) 1146 return -EFAULT; 1147 if (tmp > 255) /* max for unchar */ 1148 return -EINVAL; 1149 spin_lock_bh(&sl->lock); 1150 if (!sl->tty) { 1151 spin_unlock_bh(&sl->lock); 1152 return -ENODEV; 1153 } 1154 sl->outfill = (u8)tmp; 1155 if (sl->outfill != 0) { 1156 mod_timer(&sl->outfill_timer, 1157 jiffies + sl->outfill * HZ); 1158 set_bit(SLF_OUTWAIT, &sl->flags); 1159 } else 1160 del_timer(&sl->outfill_timer); 1161 spin_unlock_bh(&sl->lock); 1162 return 0; 1163 1164 case SIOCGOUTFILL: 1165 if (put_user(sl->outfill, p)) 1166 return -EFAULT; 1167 return 0; 1168 /* VSV changes end */ 1169#endif 1170 default: 1171 return tty_mode_ioctl(tty, file, cmd, arg); 1172 } 1173} 1174 1175#ifdef CONFIG_COMPAT 1176static long slip_compat_ioctl(struct tty_struct *tty, struct file *file, 1177 unsigned int cmd, unsigned long arg) 1178{ 1179 switch (cmd) { 1180 case SIOCGIFNAME: 1181 case SIOCGIFENCAP: 1182 case SIOCSIFENCAP: 1183 case SIOCSIFHWADDR: 1184 case SIOCSKEEPALIVE: 1185 case SIOCGKEEPALIVE: 1186 case SIOCSOUTFILL: 1187 case SIOCGOUTFILL: 1188 return slip_ioctl(tty, file, cmd, 1189 (unsigned long)compat_ptr(arg)); 1190 } 1191 1192 return -ENOIOCTLCMD; 1193} 1194#endif 1195 1196/* VSV changes start here */ 1197#ifdef CONFIG_SLIP_SMART 1198/* function do_ioctl called from net/core/dev.c 1199 to allow get/set outfill/keepalive parameter 1200 by ifconfig */ 1201 1202static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1203{ 1204 struct slip *sl = netdev_priv(dev); 1205 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1206 1207 if (sl == NULL) /* Allocation failed ?? */ 1208 return -ENODEV; 1209 1210 spin_lock_bh(&sl->lock); 1211 1212 if (!sl->tty) { 1213 spin_unlock_bh(&sl->lock); 1214 return -ENODEV; 1215 } 1216 1217 switch (cmd) { 1218 case SIOCSKEEPALIVE: 1219 /* max for unchar */ 1220 if ((unsigned)*p > 255) { 1221 spin_unlock_bh(&sl->lock); 1222 return -EINVAL; 1223 } 1224 sl->keepalive = (u8)*p; 1225 if (sl->keepalive != 0) { 1226 sl->keepalive_timer.expires = 1227 jiffies + sl->keepalive * HZ; 1228 mod_timer(&sl->keepalive_timer, 1229 jiffies + sl->keepalive * HZ); 1230 set_bit(SLF_KEEPTEST, &sl->flags); 1231 } else 1232 del_timer(&sl->keepalive_timer); 1233 break; 1234 1235 case SIOCGKEEPALIVE: 1236 *p = sl->keepalive; 1237 break; 1238 1239 case SIOCSOUTFILL: 1240 if ((unsigned)*p > 255) { /* max for unchar */ 1241 spin_unlock_bh(&sl->lock); 1242 return -EINVAL; 1243 } 1244 sl->outfill = (u8)*p; 1245 if (sl->outfill != 0) { 1246 mod_timer(&sl->outfill_timer, 1247 jiffies + sl->outfill * HZ); 1248 set_bit(SLF_OUTWAIT, &sl->flags); 1249 } else 1250 del_timer(&sl->outfill_timer); 1251 break; 1252 1253 case SIOCGOUTFILL: 1254 *p = sl->outfill; 1255 break; 1256 1257 case SIOCSLEASE: 1258 /* Resolve race condition, when ioctl'ing hanged up 1259 and opened by another process device. 1260 */ 1261 if (sl->tty != current->signal->tty && 1262 sl->pid != current->pid) { 1263 spin_unlock_bh(&sl->lock); 1264 return -EPERM; 1265 } 1266 sl->leased = 0; 1267 if (*p) 1268 sl->leased = 1; 1269 break; 1270 1271 case SIOCGLEASE: 1272 *p = sl->leased; 1273 } 1274 spin_unlock_bh(&sl->lock); 1275 return 0; 1276} 1277#endif 1278/* VSV changes end */ 1279 1280static struct tty_ldisc_ops sl_ldisc = { 1281 .owner = THIS_MODULE, 1282 .magic = TTY_LDISC_MAGIC, 1283 .name = "slip", 1284 .open = slip_open, 1285 .close = slip_close, 1286 .hangup = slip_hangup, 1287 .ioctl = slip_ioctl, 1288#ifdef CONFIG_COMPAT 1289 .compat_ioctl = slip_compat_ioctl, 1290#endif 1291 .receive_buf = slip_receive_buf, 1292 .write_wakeup = slip_write_wakeup, 1293}; 1294 1295static int __init slip_init(void) 1296{ 1297 int status; 1298 1299 if (slip_maxdev < 4) 1300 slip_maxdev = 4; /* Sanity */ 1301 1302 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" 1303#ifdef CONFIG_SLIP_MODE_SLIP6 1304 " (6 bit encapsulation enabled)" 1305#endif 1306 ".\n", 1307 SLIP_VERSION, slip_maxdev); 1308#if defined(SL_INCLUDE_CSLIP) 1309 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); 1310#endif 1311#ifdef CONFIG_SLIP_SMART 1312 printk(KERN_INFO "SLIP linefill/keepalive option.\n"); 1313#endif 1314 1315 slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev, 1316 GFP_KERNEL); 1317 if (!slip_devs) 1318 return -ENOMEM; 1319 1320 /* Fill in our line protocol discipline, and register it */ 1321 status = tty_register_ldisc(N_SLIP, &sl_ldisc); 1322 if (status != 0) { 1323 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); 1324 kfree(slip_devs); 1325 } 1326 return status; 1327} 1328 1329static void __exit slip_exit(void) 1330{ 1331 int i; 1332 struct net_device *dev; 1333 struct slip *sl; 1334 unsigned long timeout = jiffies + HZ; 1335 int busy = 0; 1336 1337 if (slip_devs == NULL) 1338 return; 1339 1340 /* First of all: check for active disciplines and hangup them. 1341 */ 1342 do { 1343 if (busy) 1344 msleep_interruptible(100); 1345 1346 busy = 0; 1347 for (i = 0; i < slip_maxdev; i++) { 1348 dev = slip_devs[i]; 1349 if (!dev) 1350 continue; 1351 sl = netdev_priv(dev); 1352 spin_lock_bh(&sl->lock); 1353 if (sl->tty) { 1354 busy++; 1355 tty_hangup(sl->tty); 1356 } 1357 spin_unlock_bh(&sl->lock); 1358 } 1359 } while (busy && time_before(jiffies, timeout)); 1360 1361 /* FIXME: hangup is async so we should wait when doing this second 1362 phase */ 1363 1364 for (i = 0; i < slip_maxdev; i++) { 1365 dev = slip_devs[i]; 1366 if (!dev) 1367 continue; 1368 slip_devs[i] = NULL; 1369 1370 sl = netdev_priv(dev); 1371 if (sl->tty) { 1372 printk(KERN_ERR "%s: tty discipline still running\n", 1373 dev->name); 1374 /* Intentionally leak the control block. */ 1375 dev->destructor = NULL; 1376 } 1377 1378 unregister_netdev(dev); 1379 } 1380 1381 kfree(slip_devs); 1382 slip_devs = NULL; 1383 1384 i = tty_unregister_ldisc(N_SLIP); 1385 if (i != 0) 1386 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1387} 1388 1389module_init(slip_init); 1390module_exit(slip_exit); 1391 1392#ifdef CONFIG_SLIP_SMART 1393/* 1394 * This is start of the code for multislip style line checking 1395 * added by Stanislav Voronyi. All changes before marked VSV 1396 */ 1397 1398static void sl_outfill(unsigned long sls) 1399{ 1400 struct slip *sl = (struct slip *)sls; 1401 1402 spin_lock(&sl->lock); 1403 1404 if (sl->tty == NULL) 1405 goto out; 1406 1407 if (sl->outfill) { 1408 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1409 /* no packets were transmitted, do outfill */ 1410#ifdef CONFIG_SLIP_MODE_SLIP6 1411 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1412#else 1413 unsigned char s = END; 1414#endif 1415 /* put END into tty queue. Is it right ??? */ 1416 if (!netif_queue_stopped(sl->dev)) { 1417 /* if device busy no outfill */ 1418 sl->tty->ops->write(sl->tty, &s, 1); 1419 } 1420 } else 1421 set_bit(SLF_OUTWAIT, &sl->flags); 1422 1423 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1424 } 1425out: 1426 spin_unlock(&sl->lock); 1427} 1428 1429static void sl_keepalive(unsigned long sls) 1430{ 1431 struct slip *sl = (struct slip *)sls; 1432 1433 spin_lock(&sl->lock); 1434 1435 if (sl->tty == NULL) 1436 goto out; 1437 1438 if (sl->keepalive) { 1439 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1440 /* keepalive still high :(, we must hangup */ 1441 if (sl->outfill) 1442 /* outfill timer must be deleted too */ 1443 (void)del_timer(&sl->outfill_timer); 1444 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1445 /* this must hangup tty & close slip */ 1446 tty_hangup(sl->tty); 1447 /* I think we need not something else */ 1448 goto out; 1449 } else 1450 set_bit(SLF_KEEPTEST, &sl->flags); 1451 1452 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1453 } 1454out: 1455 spin_unlock(&sl->lock); 1456} 1457 1458#endif 1459MODULE_LICENSE("GPL"); 1460MODULE_ALIAS_LDISC(N_SLIP); 1461