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/system.h> 68 #include <asm/uaccess.h> 69 #include <linux/bitops.h> 70 #include <linux/sched.h> 71 #include <linux/string.h> 72 #include <linux/mm.h> 73 #include <linux/interrupt.h> 74 #include <linux/in.h> 75 #include <linux/tty.h> 76 #include <linux/errno.h> 77 #include <linux/netdevice.h> 78 #include <linux/etherdevice.h> 79 #include <linux/skbuff.h> 80 #include <linux/rtnetlink.h> 81 #include <linux/if_arp.h> 82 #include <linux/if_slip.h> 83 #include <linux/compat.h> 84 #include <linux/delay.h> 85 #include <linux/init.h> 86 #include <linux/slab.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 (slcomp == NULL) 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, (unsigned char *) sl->xbuff, len); 395 else 396 #endif 397 count = slip_esc(p, (unsigned char *) 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 /* 421 * Called by the driver when there's room for more data. If we have 422 * more packets to send, we send them here. 423 */ 424 static void slip_write_wakeup(struct tty_struct *tty) 425 { 426 int actual; 427 struct slip *sl = tty->disc_data; 428 429 /* First make sure we're connected. */ 430 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 431 return; 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, &tty->flags); 438 sl_unlock(sl); 439 return; 440 } 441 442 actual = tty->ops->write(tty, sl->xhead, sl->xleft); 443 sl->xleft -= actual; 444 sl->xhead += actual; 445 } 446 447 static void sl_tx_timeout(struct net_device *dev) 448 { 449 struct slip *sl = netdev_priv(dev); 450 451 spin_lock(&sl->lock); 452 453 if (netif_queue_stopped(dev)) { 454 if (!netif_running(dev)) 455 goto out; 456 457 /* May be we must check transmitter timeout here ? 458 * 14 Oct 1994 Dmitry Gorodchanin. 459 */ 460 #ifdef SL_CHECK_TRANSMIT 461 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) { 462 /* 20 sec timeout not reached */ 463 goto out; 464 } 465 printk(KERN_WARNING "%s: transmit timed out, %s?\n", 466 dev->name, 467 (tty_chars_in_buffer(sl->tty) || sl->xleft) ? 468 "bad line quality" : "driver error"); 469 sl->xleft = 0; 470 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 471 sl_unlock(sl); 472 #endif 473 } 474 out: 475 spin_unlock(&sl->lock); 476 } 477 478 479 /* Encapsulate an IP datagram and kick it into a TTY queue. */ 480 static netdev_tx_t 481 sl_xmit(struct sk_buff *skb, struct net_device *dev) 482 { 483 struct slip *sl = netdev_priv(dev); 484 485 spin_lock(&sl->lock); 486 if (!netif_running(dev)) { 487 spin_unlock(&sl->lock); 488 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name); 489 dev_kfree_skb(skb); 490 return NETDEV_TX_OK; 491 } 492 if (sl->tty == NULL) { 493 spin_unlock(&sl->lock); 494 dev_kfree_skb(skb); 495 return NETDEV_TX_OK; 496 } 497 498 sl_lock(sl); 499 dev->stats.tx_bytes += skb->len; 500 sl_encaps(sl, skb->data, skb->len); 501 spin_unlock(&sl->lock); 502 503 dev_kfree_skb(skb); 504 return NETDEV_TX_OK; 505 } 506 507 508 /****************************************** 509 * Routines looking at netdevice side. 510 ******************************************/ 511 512 /* Netdevice UP -> DOWN routine */ 513 514 static int 515 sl_close(struct net_device *dev) 516 { 517 struct slip *sl = netdev_priv(dev); 518 519 spin_lock_bh(&sl->lock); 520 if (sl->tty) 521 /* TTY discipline is running. */ 522 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 523 netif_stop_queue(dev); 524 sl->rcount = 0; 525 sl->xleft = 0; 526 spin_unlock_bh(&sl->lock); 527 528 return 0; 529 } 530 531 /* Netdevice DOWN -> UP routine */ 532 533 static int sl_open(struct net_device *dev) 534 { 535 struct slip *sl = netdev_priv(dev); 536 537 if (sl->tty == NULL) 538 return -ENODEV; 539 540 sl->flags &= (1 << SLF_INUSE); 541 netif_start_queue(dev); 542 return 0; 543 } 544 545 /* Netdevice change MTU request */ 546 547 static int sl_change_mtu(struct net_device *dev, int new_mtu) 548 { 549 struct slip *sl = netdev_priv(dev); 550 551 if (new_mtu < 68 || new_mtu > 65534) 552 return -EINVAL; 553 554 if (new_mtu != dev->mtu) 555 return sl_realloc_bufs(sl, new_mtu); 556 return 0; 557 } 558 559 /* Netdevice get statistics request */ 560 561 static struct rtnl_link_stats64 * 562 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 563 { 564 struct net_device_stats *devstats = &dev->stats; 565 #ifdef SL_INCLUDE_CSLIP 566 struct slip *sl = netdev_priv(dev); 567 struct slcompress *comp = sl->slcomp; 568 #endif 569 stats->rx_packets = devstats->rx_packets; 570 stats->tx_packets = devstats->tx_packets; 571 stats->rx_bytes = devstats->rx_bytes; 572 stats->tx_bytes = devstats->tx_bytes; 573 stats->rx_dropped = devstats->rx_dropped; 574 stats->tx_dropped = devstats->tx_dropped; 575 stats->tx_errors = devstats->tx_errors; 576 stats->rx_errors = devstats->rx_errors; 577 stats->rx_over_errors = devstats->rx_over_errors; 578 579 #ifdef SL_INCLUDE_CSLIP 580 if (comp) { 581 /* Generic compressed statistics */ 582 stats->rx_compressed = comp->sls_i_compressed; 583 stats->tx_compressed = comp->sls_o_compressed; 584 585 /* Are we really still needs this? */ 586 stats->rx_fifo_errors += comp->sls_i_compressed; 587 stats->rx_dropped += comp->sls_i_tossed; 588 stats->tx_fifo_errors += comp->sls_o_compressed; 589 stats->collisions += comp->sls_o_misses; 590 } 591 #endif 592 return stats; 593 } 594 595 /* Netdevice register callback */ 596 597 static int sl_init(struct net_device *dev) 598 { 599 struct slip *sl = netdev_priv(dev); 600 601 /* 602 * Finish setting up the DEVICE info. 603 */ 604 605 dev->mtu = sl->mtu; 606 dev->type = ARPHRD_SLIP + sl->mode; 607 #ifdef SL_CHECK_TRANSMIT 608 dev->watchdog_timeo = 20*HZ; 609 #endif 610 return 0; 611 } 612 613 614 static void sl_uninit(struct net_device *dev) 615 { 616 struct slip *sl = netdev_priv(dev); 617 618 sl_free_bufs(sl); 619 } 620 621 /* Hook the destructor so we can free slip devices at the right point in time */ 622 static void sl_free_netdev(struct net_device *dev) 623 { 624 int i = dev->base_addr; 625 free_netdev(dev); 626 slip_devs[i] = NULL; 627 } 628 629 static const struct net_device_ops sl_netdev_ops = { 630 .ndo_init = sl_init, 631 .ndo_uninit = sl_uninit, 632 .ndo_open = sl_open, 633 .ndo_stop = sl_close, 634 .ndo_start_xmit = sl_xmit, 635 .ndo_get_stats64 = sl_get_stats64, 636 .ndo_change_mtu = sl_change_mtu, 637 .ndo_tx_timeout = sl_tx_timeout, 638 #ifdef CONFIG_SLIP_SMART 639 .ndo_do_ioctl = sl_ioctl, 640 #endif 641 }; 642 643 644 static void sl_setup(struct net_device *dev) 645 { 646 dev->netdev_ops = &sl_netdev_ops; 647 dev->destructor = sl_free_netdev; 648 649 dev->hard_header_len = 0; 650 dev->addr_len = 0; 651 dev->tx_queue_len = 10; 652 653 /* New-style flags. */ 654 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 655 } 656 657 /****************************************** 658 Routines looking at TTY side. 659 ******************************************/ 660 661 662 /* 663 * Handle the 'receiver data ready' interrupt. 664 * This function is called by the 'tty_io' module in the kernel when 665 * a block of SLIP data has been received, which can now be decapsulated 666 * and sent on to some IP layer for further processing. This will not 667 * be re-entered while running but other ldisc functions may be called 668 * in parallel 669 */ 670 671 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 672 char *fp, int count) 673 { 674 struct slip *sl = tty->disc_data; 675 676 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 677 return; 678 679 /* Read the characters out of the buffer */ 680 while (count--) { 681 if (fp && *fp++) { 682 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 683 sl->dev->stats.rx_errors++; 684 cp++; 685 continue; 686 } 687 #ifdef CONFIG_SLIP_MODE_SLIP6 688 if (sl->mode & SL_MODE_SLIP6) 689 slip_unesc6(sl, *cp++); 690 else 691 #endif 692 slip_unesc(sl, *cp++); 693 } 694 } 695 696 /************************************ 697 * slip_open helper routines. 698 ************************************/ 699 700 /* Collect hanged up channels */ 701 static void sl_sync(void) 702 { 703 int i; 704 struct net_device *dev; 705 struct slip *sl; 706 707 for (i = 0; i < slip_maxdev; i++) { 708 dev = slip_devs[i]; 709 if (dev == NULL) 710 break; 711 712 sl = netdev_priv(dev); 713 if (sl->tty || sl->leased) 714 continue; 715 if (dev->flags & IFF_UP) 716 dev_close(dev); 717 } 718 } 719 720 721 /* Find a free SLIP channel, and link in this `tty' line. */ 722 static struct slip *sl_alloc(dev_t line) 723 { 724 int i; 725 char name[IFNAMSIZ]; 726 struct net_device *dev = NULL; 727 struct slip *sl; 728 729 for (i = 0; i < slip_maxdev; i++) { 730 dev = slip_devs[i]; 731 if (dev == NULL) 732 break; 733 } 734 /* Sorry, too many, all slots in use */ 735 if (i >= slip_maxdev) 736 return NULL; 737 738 sprintf(name, "sl%d", i); 739 dev = alloc_netdev(sizeof(*sl), name, sl_setup); 740 if (!dev) 741 return NULL; 742 743 dev->base_addr = i; 744 sl = netdev_priv(dev); 745 746 /* Initialize channel control data */ 747 sl->magic = SLIP_MAGIC; 748 sl->dev = dev; 749 spin_lock_init(&sl->lock); 750 sl->mode = SL_MODE_DEFAULT; 751 #ifdef CONFIG_SLIP_SMART 752 /* initialize timer_list struct */ 753 init_timer(&sl->keepalive_timer); 754 sl->keepalive_timer.data = (unsigned long)sl; 755 sl->keepalive_timer.function = sl_keepalive; 756 init_timer(&sl->outfill_timer); 757 sl->outfill_timer.data = (unsigned long)sl; 758 sl->outfill_timer.function = sl_outfill; 759 #endif 760 slip_devs[i] = dev; 761 return sl; 762 } 763 764 /* 765 * Open the high-level part of the SLIP channel. 766 * This function is called by the TTY module when the 767 * SLIP line discipline is called for. Because we are 768 * sure the tty line exists, we only have to link it to 769 * a free SLIP channel... 770 * 771 * Called in process context serialized from other ldisc calls. 772 */ 773 774 static int slip_open(struct tty_struct *tty) 775 { 776 struct slip *sl; 777 int err; 778 779 if (!capable(CAP_NET_ADMIN)) 780 return -EPERM; 781 782 if (tty->ops->write == NULL) 783 return -EOPNOTSUPP; 784 785 /* RTnetlink lock is misused here to serialize concurrent 786 opens of slip channels. There are better ways, but it is 787 the simplest one. 788 */ 789 rtnl_lock(); 790 791 /* Collect hanged up channels. */ 792 sl_sync(); 793 794 sl = tty->disc_data; 795 796 err = -EEXIST; 797 /* First make sure we're not already connected. */ 798 if (sl && sl->magic == SLIP_MAGIC) 799 goto err_exit; 800 801 /* OK. Find a free SLIP channel to use. */ 802 err = -ENFILE; 803 sl = sl_alloc(tty_devnum(tty)); 804 if (sl == NULL) 805 goto err_exit; 806 807 sl->tty = tty; 808 tty->disc_data = sl; 809 sl->pid = current->pid; 810 811 if (!test_bit(SLF_INUSE, &sl->flags)) { 812 /* Perform the low-level SLIP initialization. */ 813 err = sl_alloc_bufs(sl, SL_MTU); 814 if (err) 815 goto err_free_chan; 816 817 set_bit(SLF_INUSE, &sl->flags); 818 819 err = register_netdevice(sl->dev); 820 if (err) 821 goto err_free_bufs; 822 } 823 824 #ifdef CONFIG_SLIP_SMART 825 if (sl->keepalive) { 826 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 827 add_timer(&sl->keepalive_timer); 828 } 829 if (sl->outfill) { 830 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 831 add_timer(&sl->outfill_timer); 832 } 833 #endif 834 835 /* Done. We have linked the TTY line to a channel. */ 836 rtnl_unlock(); 837 tty->receive_room = 65536; /* We don't flow control */ 838 839 /* TTY layer expects 0 on success */ 840 return 0; 841 842 err_free_bufs: 843 sl_free_bufs(sl); 844 845 err_free_chan: 846 sl->tty = NULL; 847 tty->disc_data = NULL; 848 clear_bit(SLF_INUSE, &sl->flags); 849 850 err_exit: 851 rtnl_unlock(); 852 853 /* Count references from TTY module */ 854 return err; 855 } 856 857 /* 858 * Close down a SLIP channel. 859 * This means flushing out any pending queues, and then returning. This 860 * call is serialized against other ldisc functions. 861 * 862 * We also use this method fo a hangup event 863 */ 864 865 static void slip_close(struct tty_struct *tty) 866 { 867 struct slip *sl = tty->disc_data; 868 869 /* First make sure we're connected. */ 870 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 871 return; 872 873 tty->disc_data = NULL; 874 sl->tty = NULL; 875 876 /* VSV = very important to remove timers */ 877 #ifdef CONFIG_SLIP_SMART 878 del_timer_sync(&sl->keepalive_timer); 879 del_timer_sync(&sl->outfill_timer); 880 #endif 881 /* Flush network side */ 882 unregister_netdev(sl->dev); 883 /* This will complete via sl_free_netdev */ 884 } 885 886 static int slip_hangup(struct tty_struct *tty) 887 { 888 slip_close(tty); 889 return 0; 890 } 891 /************************************************************************ 892 * STANDARD SLIP ENCAPSULATION * 893 ************************************************************************/ 894 895 static int slip_esc(unsigned char *s, unsigned char *d, int len) 896 { 897 unsigned char *ptr = d; 898 unsigned char c; 899 900 /* 901 * Send an initial END character to flush out any 902 * data that may have accumulated in the receiver 903 * due to line noise. 904 */ 905 906 *ptr++ = END; 907 908 /* 909 * For each byte in the packet, send the appropriate 910 * character sequence, according to the SLIP protocol. 911 */ 912 913 while (len-- > 0) { 914 switch (c = *s++) { 915 case END: 916 *ptr++ = ESC; 917 *ptr++ = ESC_END; 918 break; 919 case ESC: 920 *ptr++ = ESC; 921 *ptr++ = ESC_ESC; 922 break; 923 default: 924 *ptr++ = c; 925 break; 926 } 927 } 928 *ptr++ = END; 929 return ptr - d; 930 } 931 932 static void slip_unesc(struct slip *sl, unsigned char s) 933 { 934 935 switch (s) { 936 case END: 937 #ifdef CONFIG_SLIP_SMART 938 /* drop keeptest bit = VSV */ 939 if (test_bit(SLF_KEEPTEST, &sl->flags)) 940 clear_bit(SLF_KEEPTEST, &sl->flags); 941 #endif 942 943 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 944 (sl->rcount > 2)) 945 sl_bump(sl); 946 clear_bit(SLF_ESCAPE, &sl->flags); 947 sl->rcount = 0; 948 return; 949 950 case ESC: 951 set_bit(SLF_ESCAPE, &sl->flags); 952 return; 953 case ESC_ESC: 954 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 955 s = ESC; 956 break; 957 case ESC_END: 958 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 959 s = END; 960 break; 961 } 962 if (!test_bit(SLF_ERROR, &sl->flags)) { 963 if (sl->rcount < sl->buffsize) { 964 sl->rbuff[sl->rcount++] = s; 965 return; 966 } 967 sl->dev->stats.rx_over_errors++; 968 set_bit(SLF_ERROR, &sl->flags); 969 } 970 } 971 972 973 #ifdef CONFIG_SLIP_MODE_SLIP6 974 /************************************************************************ 975 * 6 BIT SLIP ENCAPSULATION * 976 ************************************************************************/ 977 978 static int slip_esc6(unsigned char *s, unsigned char *d, int len) 979 { 980 unsigned char *ptr = d; 981 unsigned char c; 982 int i; 983 unsigned short v = 0; 984 short bits = 0; 985 986 /* 987 * Send an initial END character to flush out any 988 * data that may have accumulated in the receiver 989 * due to line noise. 990 */ 991 992 *ptr++ = 0x70; 993 994 /* 995 * Encode the packet into printable ascii characters 996 */ 997 998 for (i = 0; i < len; ++i) { 999 v = (v << 8) | s[i]; 1000 bits += 8; 1001 while (bits >= 6) { 1002 bits -= 6; 1003 c = 0x30 + ((v >> bits) & 0x3F); 1004 *ptr++ = c; 1005 } 1006 } 1007 if (bits) { 1008 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1009 *ptr++ = c; 1010 } 1011 *ptr++ = 0x70; 1012 return ptr - d; 1013 } 1014 1015 static void slip_unesc6(struct slip *sl, unsigned char s) 1016 { 1017 unsigned char c; 1018 1019 if (s == 0x70) { 1020 #ifdef CONFIG_SLIP_SMART 1021 /* drop keeptest bit = VSV */ 1022 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1023 clear_bit(SLF_KEEPTEST, &sl->flags); 1024 #endif 1025 1026 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1027 (sl->rcount > 2)) 1028 sl_bump(sl); 1029 sl->rcount = 0; 1030 sl->xbits = 0; 1031 sl->xdata = 0; 1032 } else if (s >= 0x30 && s < 0x70) { 1033 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1034 sl->xbits += 6; 1035 if (sl->xbits >= 8) { 1036 sl->xbits -= 8; 1037 c = (unsigned char)(sl->xdata >> sl->xbits); 1038 if (!test_bit(SLF_ERROR, &sl->flags)) { 1039 if (sl->rcount < sl->buffsize) { 1040 sl->rbuff[sl->rcount++] = c; 1041 return; 1042 } 1043 sl->dev->stats.rx_over_errors++; 1044 set_bit(SLF_ERROR, &sl->flags); 1045 } 1046 } 1047 } 1048 } 1049 #endif /* CONFIG_SLIP_MODE_SLIP6 */ 1050 1051 /* Perform I/O control on an active SLIP channel. */ 1052 static int slip_ioctl(struct tty_struct *tty, struct file *file, 1053 unsigned int cmd, unsigned long arg) 1054 { 1055 struct slip *sl = tty->disc_data; 1056 unsigned int tmp; 1057 int __user *p = (int __user *)arg; 1058 1059 /* First make sure we're connected. */ 1060 if (!sl || sl->magic != SLIP_MAGIC) 1061 return -EINVAL; 1062 1063 switch (cmd) { 1064 case SIOCGIFNAME: 1065 tmp = strlen(sl->dev->name) + 1; 1066 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1067 return -EFAULT; 1068 return 0; 1069 1070 case SIOCGIFENCAP: 1071 if (put_user(sl->mode, p)) 1072 return -EFAULT; 1073 return 0; 1074 1075 case SIOCSIFENCAP: 1076 if (get_user(tmp, p)) 1077 return -EFAULT; 1078 #ifndef SL_INCLUDE_CSLIP 1079 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1080 return -EINVAL; 1081 #else 1082 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1083 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1084 /* return -EINVAL; */ 1085 tmp &= ~SL_MODE_ADAPTIVE; 1086 #endif 1087 #ifndef CONFIG_SLIP_MODE_SLIP6 1088 if (tmp & SL_MODE_SLIP6) 1089 return -EINVAL; 1090 #endif 1091 sl->mode = tmp; 1092 sl->dev->type = ARPHRD_SLIP + sl->mode; 1093 return 0; 1094 1095 case SIOCSIFHWADDR: 1096 return -EINVAL; 1097 1098 #ifdef CONFIG_SLIP_SMART 1099 /* VSV changes start here */ 1100 case SIOCSKEEPALIVE: 1101 if (get_user(tmp, p)) 1102 return -EFAULT; 1103 if (tmp > 255) /* max for unchar */ 1104 return -EINVAL; 1105 1106 spin_lock_bh(&sl->lock); 1107 if (!sl->tty) { 1108 spin_unlock_bh(&sl->lock); 1109 return -ENODEV; 1110 } 1111 sl->keepalive = (u8)tmp; 1112 if (sl->keepalive != 0) { 1113 mod_timer(&sl->keepalive_timer, 1114 jiffies + sl->keepalive * HZ); 1115 set_bit(SLF_KEEPTEST, &sl->flags); 1116 } else 1117 del_timer(&sl->keepalive_timer); 1118 spin_unlock_bh(&sl->lock); 1119 return 0; 1120 1121 case SIOCGKEEPALIVE: 1122 if (put_user(sl->keepalive, p)) 1123 return -EFAULT; 1124 return 0; 1125 1126 case SIOCSOUTFILL: 1127 if (get_user(tmp, p)) 1128 return -EFAULT; 1129 if (tmp > 255) /* max for unchar */ 1130 return -EINVAL; 1131 spin_lock_bh(&sl->lock); 1132 if (!sl->tty) { 1133 spin_unlock_bh(&sl->lock); 1134 return -ENODEV; 1135 } 1136 sl->outfill = (u8)tmp; 1137 if (sl->outfill != 0) { 1138 mod_timer(&sl->outfill_timer, 1139 jiffies + sl->outfill * HZ); 1140 set_bit(SLF_OUTWAIT, &sl->flags); 1141 } else 1142 del_timer(&sl->outfill_timer); 1143 spin_unlock_bh(&sl->lock); 1144 return 0; 1145 1146 case SIOCGOUTFILL: 1147 if (put_user(sl->outfill, p)) 1148 return -EFAULT; 1149 return 0; 1150 /* VSV changes end */ 1151 #endif 1152 default: 1153 return tty_mode_ioctl(tty, file, cmd, arg); 1154 } 1155 } 1156 1157 #ifdef CONFIG_COMPAT 1158 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file, 1159 unsigned int cmd, unsigned long arg) 1160 { 1161 switch (cmd) { 1162 case SIOCGIFNAME: 1163 case SIOCGIFENCAP: 1164 case SIOCSIFENCAP: 1165 case SIOCSIFHWADDR: 1166 case SIOCSKEEPALIVE: 1167 case SIOCGKEEPALIVE: 1168 case SIOCSOUTFILL: 1169 case SIOCGOUTFILL: 1170 return slip_ioctl(tty, file, cmd, 1171 (unsigned long)compat_ptr(arg)); 1172 } 1173 1174 return -ENOIOCTLCMD; 1175 } 1176 #endif 1177 1178 /* VSV changes start here */ 1179 #ifdef CONFIG_SLIP_SMART 1180 /* function do_ioctl called from net/core/dev.c 1181 to allow get/set outfill/keepalive parameter 1182 by ifconfig */ 1183 1184 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1185 { 1186 struct slip *sl = netdev_priv(dev); 1187 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1188 1189 if (sl == NULL) /* Allocation failed ?? */ 1190 return -ENODEV; 1191 1192 spin_lock_bh(&sl->lock); 1193 1194 if (!sl->tty) { 1195 spin_unlock_bh(&sl->lock); 1196 return -ENODEV; 1197 } 1198 1199 switch (cmd) { 1200 case SIOCSKEEPALIVE: 1201 /* max for unchar */ 1202 if ((unsigned)*p > 255) { 1203 spin_unlock_bh(&sl->lock); 1204 return -EINVAL; 1205 } 1206 sl->keepalive = (u8)*p; 1207 if (sl->keepalive != 0) { 1208 sl->keepalive_timer.expires = 1209 jiffies + sl->keepalive * HZ; 1210 mod_timer(&sl->keepalive_timer, 1211 jiffies + sl->keepalive * HZ); 1212 set_bit(SLF_KEEPTEST, &sl->flags); 1213 } else 1214 del_timer(&sl->keepalive_timer); 1215 break; 1216 1217 case SIOCGKEEPALIVE: 1218 *p = sl->keepalive; 1219 break; 1220 1221 case SIOCSOUTFILL: 1222 if ((unsigned)*p > 255) { /* max for unchar */ 1223 spin_unlock_bh(&sl->lock); 1224 return -EINVAL; 1225 } 1226 sl->outfill = (u8)*p; 1227 if (sl->outfill != 0) { 1228 mod_timer(&sl->outfill_timer, 1229 jiffies + sl->outfill * HZ); 1230 set_bit(SLF_OUTWAIT, &sl->flags); 1231 } else 1232 del_timer(&sl->outfill_timer); 1233 break; 1234 1235 case SIOCGOUTFILL: 1236 *p = sl->outfill; 1237 break; 1238 1239 case SIOCSLEASE: 1240 /* Resolve race condition, when ioctl'ing hanged up 1241 and opened by another process device. 1242 */ 1243 if (sl->tty != current->signal->tty && 1244 sl->pid != current->pid) { 1245 spin_unlock_bh(&sl->lock); 1246 return -EPERM; 1247 } 1248 sl->leased = 0; 1249 if (*p) 1250 sl->leased = 1; 1251 break; 1252 1253 case SIOCGLEASE: 1254 *p = sl->leased; 1255 } 1256 spin_unlock_bh(&sl->lock); 1257 return 0; 1258 } 1259 #endif 1260 /* VSV changes end */ 1261 1262 static struct tty_ldisc_ops sl_ldisc = { 1263 .owner = THIS_MODULE, 1264 .magic = TTY_LDISC_MAGIC, 1265 .name = "slip", 1266 .open = slip_open, 1267 .close = slip_close, 1268 .hangup = slip_hangup, 1269 .ioctl = slip_ioctl, 1270 #ifdef CONFIG_COMPAT 1271 .compat_ioctl = slip_compat_ioctl, 1272 #endif 1273 .receive_buf = slip_receive_buf, 1274 .write_wakeup = slip_write_wakeup, 1275 }; 1276 1277 static int __init slip_init(void) 1278 { 1279 int status; 1280 1281 if (slip_maxdev < 4) 1282 slip_maxdev = 4; /* Sanity */ 1283 1284 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" 1285 #ifdef CONFIG_SLIP_MODE_SLIP6 1286 " (6 bit encapsulation enabled)" 1287 #endif 1288 ".\n", 1289 SLIP_VERSION, slip_maxdev); 1290 #if defined(SL_INCLUDE_CSLIP) 1291 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); 1292 #endif 1293 #ifdef CONFIG_SLIP_SMART 1294 printk(KERN_INFO "SLIP linefill/keepalive option.\n"); 1295 #endif 1296 1297 slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev, 1298 GFP_KERNEL); 1299 if (!slip_devs) { 1300 printk(KERN_ERR "SLIP: Can't allocate slip devices array.\n"); 1301 return -ENOMEM; 1302 } 1303 1304 /* Fill in our line protocol discipline, and register it */ 1305 status = tty_register_ldisc(N_SLIP, &sl_ldisc); 1306 if (status != 0) { 1307 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); 1308 kfree(slip_devs); 1309 } 1310 return status; 1311 } 1312 1313 static void __exit slip_exit(void) 1314 { 1315 int i; 1316 struct net_device *dev; 1317 struct slip *sl; 1318 unsigned long timeout = jiffies + HZ; 1319 int busy = 0; 1320 1321 if (slip_devs == NULL) 1322 return; 1323 1324 /* First of all: check for active disciplines and hangup them. 1325 */ 1326 do { 1327 if (busy) 1328 msleep_interruptible(100); 1329 1330 busy = 0; 1331 for (i = 0; i < slip_maxdev; i++) { 1332 dev = slip_devs[i]; 1333 if (!dev) 1334 continue; 1335 sl = netdev_priv(dev); 1336 spin_lock_bh(&sl->lock); 1337 if (sl->tty) { 1338 busy++; 1339 tty_hangup(sl->tty); 1340 } 1341 spin_unlock_bh(&sl->lock); 1342 } 1343 } while (busy && time_before(jiffies, timeout)); 1344 1345 /* FIXME: hangup is async so we should wait when doing this second 1346 phase */ 1347 1348 for (i = 0; i < slip_maxdev; i++) { 1349 dev = slip_devs[i]; 1350 if (!dev) 1351 continue; 1352 slip_devs[i] = NULL; 1353 1354 sl = netdev_priv(dev); 1355 if (sl->tty) { 1356 printk(KERN_ERR "%s: tty discipline still running\n", 1357 dev->name); 1358 /* Intentionally leak the control block. */ 1359 dev->destructor = NULL; 1360 } 1361 1362 unregister_netdev(dev); 1363 } 1364 1365 kfree(slip_devs); 1366 slip_devs = NULL; 1367 1368 i = tty_unregister_ldisc(N_SLIP); 1369 if (i != 0) 1370 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1371 } 1372 1373 module_init(slip_init); 1374 module_exit(slip_exit); 1375 1376 #ifdef CONFIG_SLIP_SMART 1377 /* 1378 * This is start of the code for multislip style line checking 1379 * added by Stanislav Voronyi. All changes before marked VSV 1380 */ 1381 1382 static void sl_outfill(unsigned long sls) 1383 { 1384 struct slip *sl = (struct slip *)sls; 1385 1386 spin_lock(&sl->lock); 1387 1388 if (sl->tty == NULL) 1389 goto out; 1390 1391 if (sl->outfill) { 1392 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1393 /* no packets were transmitted, do outfill */ 1394 #ifdef CONFIG_SLIP_MODE_SLIP6 1395 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1396 #else 1397 unsigned char s = END; 1398 #endif 1399 /* put END into tty queue. Is it right ??? */ 1400 if (!netif_queue_stopped(sl->dev)) { 1401 /* if device busy no outfill */ 1402 sl->tty->ops->write(sl->tty, &s, 1); 1403 } 1404 } else 1405 set_bit(SLF_OUTWAIT, &sl->flags); 1406 1407 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1408 } 1409 out: 1410 spin_unlock(&sl->lock); 1411 } 1412 1413 static void sl_keepalive(unsigned long sls) 1414 { 1415 struct slip *sl = (struct slip *)sls; 1416 1417 spin_lock(&sl->lock); 1418 1419 if (sl->tty == NULL) 1420 goto out; 1421 1422 if (sl->keepalive) { 1423 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1424 /* keepalive still high :(, we must hangup */ 1425 if (sl->outfill) 1426 /* outfill timer must be deleted too */ 1427 (void)del_timer(&sl->outfill_timer); 1428 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1429 /* this must hangup tty & close slip */ 1430 tty_hangup(sl->tty); 1431 /* I think we need not something else */ 1432 goto out; 1433 } else 1434 set_bit(SLF_KEEPTEST, &sl->flags); 1435 1436 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1437 } 1438 out: 1439 spin_unlock(&sl->lock); 1440 } 1441 1442 #endif 1443 MODULE_LICENSE("GPL"); 1444 MODULE_ALIAS_LDISC(N_SLIP); 1445