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 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 (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#ifdef CONFIG_SLIP_MODE_SLIP6 186 sl->xdata = 0; 187 sl->xbits = 0; 188#endif 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 if (slcomp) 198 slhc_free(slcomp); 199#endif 200 kfree(xbuff); 201 kfree(rbuff); 202 return err; 203} 204 205/* Free a SLIP channel buffers. */ 206static void sl_free_bufs(struct slip *sl) 207{ 208 /* Free all SLIP frame buffers. */ 209 kfree(xchg(&sl->rbuff, NULL)); 210 kfree(xchg(&sl->xbuff, NULL)); 211#ifdef SL_INCLUDE_CSLIP 212 kfree(xchg(&sl->cbuff, NULL)); 213 slhc_free(xchg(&sl->slcomp, NULL)); 214#endif 215} 216 217/* 218 Reallocate slip channel buffers. 219 */ 220 221static int sl_realloc_bufs(struct slip *sl, int mtu) 222{ 223 int err = 0; 224 struct net_device *dev = sl->dev; 225 unsigned char *xbuff, *rbuff; 226#ifdef SL_INCLUDE_CSLIP 227 unsigned char *cbuff; 228#endif 229 int len = mtu * 2; 230 231/* 232 * allow for arrival of larger UDP packets, even if we say not to 233 * also fixes a bug in which SunOS sends 512-byte packets even with 234 * an MSS of 128 235 */ 236 if (len < 576 * 2) 237 len = 576 * 2; 238 239 xbuff = kmalloc(len + 4, GFP_ATOMIC); 240 rbuff = kmalloc(len + 4, GFP_ATOMIC); 241#ifdef SL_INCLUDE_CSLIP 242 cbuff = kmalloc(len + 4, GFP_ATOMIC); 243#endif 244 245 246#ifdef SL_INCLUDE_CSLIP 247 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) { 248#else 249 if (xbuff == NULL || rbuff == NULL) { 250#endif 251 if (mtu >= sl->mtu) { 252 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n", 253 dev->name); 254 err = -ENOBUFS; 255 } 256 goto done; 257 } 258 spin_lock_bh(&sl->lock); 259 260 err = -ENODEV; 261 if (sl->tty == NULL) 262 goto done_on_bh; 263 264 xbuff = xchg(&sl->xbuff, xbuff); 265 rbuff = xchg(&sl->rbuff, rbuff); 266#ifdef SL_INCLUDE_CSLIP 267 cbuff = xchg(&sl->cbuff, cbuff); 268#endif 269 if (sl->xleft) { 270 if (sl->xleft <= len) { 271 memcpy(sl->xbuff, sl->xhead, sl->xleft); 272 } else { 273 sl->xleft = 0; 274 sl->tx_dropped++; 275 } 276 } 277 sl->xhead = sl->xbuff; 278 279 if (sl->rcount) { 280 if (sl->rcount <= len) { 281 memcpy(sl->rbuff, rbuff, sl->rcount); 282 } else { 283 sl->rcount = 0; 284 sl->rx_over_errors++; 285 set_bit(SLF_ERROR, &sl->flags); 286 } 287 } 288 sl->mtu = mtu; 289 dev->mtu = mtu; 290 sl->buffsize = len; 291 err = 0; 292 293done_on_bh: 294 spin_unlock_bh(&sl->lock); 295 296done: 297 kfree(xbuff); 298 kfree(rbuff); 299#ifdef SL_INCLUDE_CSLIP 300 kfree(cbuff); 301#endif 302 return err; 303} 304 305 306/* Set the "sending" flag. This must be atomic hence the set_bit. */ 307static inline void sl_lock(struct slip *sl) 308{ 309 netif_stop_queue(sl->dev); 310} 311 312 313/* Clear the "sending" flag. This must be atomic, hence the ASM. */ 314static inline void sl_unlock(struct slip *sl) 315{ 316 netif_wake_queue(sl->dev); 317} 318 319/* Send one completely decapsulated IP datagram to the IP layer. */ 320static void sl_bump(struct slip *sl) 321{ 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", sl->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 sl->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", sl->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 sl->rx_bytes += count; 359 360 skb = dev_alloc_skb(count); 361 if (skb == NULL) { 362 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", sl->dev->name); 363 sl->rx_dropped++; 364 return; 365 } 366 skb->dev = sl->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(skb); 371 sl->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->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 */ 424static 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->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 447static 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 } 474out: 475 spin_unlock(&sl->lock); 476} 477 478 479/* Encapsulate an IP datagram and kick it into a TTY queue. */ 480static netdev_tx_t 481sl_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 sl->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 514static int 515sl_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 533static 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 547static 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 561static struct net_device_stats * 562sl_get_stats(struct net_device *dev) 563{ 564 static struct net_device_stats stats; 565 struct slip *sl = netdev_priv(dev); 566#ifdef SL_INCLUDE_CSLIP 567 struct slcompress *comp; 568#endif 569 570 memset(&stats, 0, sizeof(struct net_device_stats)); 571 572 stats.rx_packets = sl->rx_packets; 573 stats.tx_packets = sl->tx_packets; 574 stats.rx_bytes = sl->rx_bytes; 575 stats.tx_bytes = sl->tx_bytes; 576 stats.rx_dropped = sl->rx_dropped; 577 stats.tx_dropped = sl->tx_dropped; 578 stats.tx_errors = sl->tx_errors; 579 stats.rx_errors = sl->rx_errors; 580 stats.rx_over_errors = sl->rx_over_errors; 581#ifdef SL_INCLUDE_CSLIP 582 stats.rx_fifo_errors = sl->rx_compressed; 583 stats.tx_fifo_errors = sl->tx_compressed; 584 stats.collisions = sl->tx_misses; 585 comp = sl->slcomp; 586 if (comp) { 587 stats.rx_fifo_errors += comp->sls_i_compressed; 588 stats.rx_dropped += comp->sls_i_tossed; 589 stats.tx_fifo_errors += comp->sls_o_compressed; 590 stats.collisions += comp->sls_o_misses; 591 } 592#endif /* CONFIG_INET */ 593 return (&stats); 594} 595 596/* Netdevice register callback */ 597 598static int sl_init(struct net_device *dev) 599{ 600 struct slip *sl = netdev_priv(dev); 601 602 /* 603 * Finish setting up the DEVICE info. 604 */ 605 606 dev->mtu = sl->mtu; 607 dev->type = ARPHRD_SLIP + sl->mode; 608#ifdef SL_CHECK_TRANSMIT 609 dev->watchdog_timeo = 20*HZ; 610#endif 611 return 0; 612} 613 614 615static void sl_uninit(struct net_device *dev) 616{ 617 struct slip *sl = netdev_priv(dev); 618 619 sl_free_bufs(sl); 620} 621 622/* Hook the destructor so we can free slip devices at the right point in time */ 623static void sl_free_netdev(struct net_device *dev) 624{ 625 int i = dev->base_addr; 626 free_netdev(dev); 627 slip_devs[i] = NULL; 628} 629 630static const struct net_device_ops sl_netdev_ops = { 631 .ndo_init = sl_init, 632 .ndo_uninit = sl_uninit, 633 .ndo_open = sl_open, 634 .ndo_stop = sl_close, 635 .ndo_start_xmit = sl_xmit, 636 .ndo_get_stats = sl_get_stats, 637 .ndo_change_mtu = sl_change_mtu, 638 .ndo_tx_timeout = sl_tx_timeout, 639#ifdef CONFIG_SLIP_SMART 640 .ndo_do_ioctl = sl_ioctl, 641#endif 642}; 643 644 645static void sl_setup(struct net_device *dev) 646{ 647 dev->netdev_ops = &sl_netdev_ops; 648 dev->destructor = sl_free_netdev; 649 650 dev->hard_header_len = 0; 651 dev->addr_len = 0; 652 dev->tx_queue_len = 10; 653 654 /* New-style flags. */ 655 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 656} 657 658/****************************************** 659 Routines looking at TTY side. 660 ******************************************/ 661 662 663/* 664 * Handle the 'receiver data ready' interrupt. 665 * This function is called by the 'tty_io' module in the kernel when 666 * a block of SLIP data has been received, which can now be decapsulated 667 * and sent on to some IP layer for further processing. This will not 668 * be re-entered while running but other ldisc functions may be called 669 * in parallel 670 */ 671 672static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 673 char *fp, int count) 674{ 675 struct slip *sl = tty->disc_data; 676 677 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 678 return; 679 680 /* Read the characters out of the buffer */ 681 while (count--) { 682 if (fp && *fp++) { 683 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 684 sl->rx_errors++; 685 cp++; 686 continue; 687 } 688#ifdef CONFIG_SLIP_MODE_SLIP6 689 if (sl->mode & SL_MODE_SLIP6) 690 slip_unesc6(sl, *cp++); 691 else 692#endif 693 slip_unesc(sl, *cp++); 694 } 695} 696 697/************************************ 698 * slip_open helper routines. 699 ************************************/ 700 701/* Collect hanged up channels */ 702static void sl_sync(void) 703{ 704 int i; 705 struct net_device *dev; 706 struct slip *sl; 707 708 for (i = 0; i < slip_maxdev; i++) { 709 dev = slip_devs[i]; 710 if (dev == NULL) 711 break; 712 713 sl = netdev_priv(dev); 714 if (sl->tty || sl->leased) 715 continue; 716 if (dev->flags & IFF_UP) 717 dev_close(dev); 718 } 719} 720 721 722/* Find a free SLIP channel, and link in this `tty' line. */ 723static struct slip *sl_alloc(dev_t line) 724{ 725 int i; 726 struct net_device *dev = NULL; 727 struct slip *sl; 728 729 if (slip_devs == NULL) 730 return NULL; /* Master array missing ! */ 731 732 for (i = 0; i < slip_maxdev; i++) { 733 dev = slip_devs[i]; 734 if (dev == NULL) 735 break; 736 } 737 /* Sorry, too many, all slots in use */ 738 if (i >= slip_maxdev) 739 return NULL; 740 741 if (dev) { 742 sl = netdev_priv(dev); 743 if (test_bit(SLF_INUSE, &sl->flags)) { 744 unregister_netdevice(dev); 745 dev = NULL; 746 slip_devs[i] = NULL; 747 } 748 } 749 750 if (!dev) { 751 char name[IFNAMSIZ]; 752 sprintf(name, "sl%d", i); 753 754 dev = alloc_netdev(sizeof(*sl), name, sl_setup); 755 if (!dev) 756 return NULL; 757 dev->base_addr = i; 758 } 759 760 sl = netdev_priv(dev); 761 762 /* Initialize channel control data */ 763 sl->magic = SLIP_MAGIC; 764 sl->dev = dev; 765 spin_lock_init(&sl->lock); 766 sl->mode = SL_MODE_DEFAULT; 767#ifdef CONFIG_SLIP_SMART 768 /* initialize timer_list struct */ 769 init_timer(&sl->keepalive_timer); 770 sl->keepalive_timer.data = (unsigned long)sl; 771 sl->keepalive_timer.function = sl_keepalive; 772 init_timer(&sl->outfill_timer); 773 sl->outfill_timer.data = (unsigned long)sl; 774 sl->outfill_timer.function = sl_outfill; 775#endif 776 slip_devs[i] = dev; 777 return sl; 778} 779 780/* 781 * Open the high-level part of the SLIP channel. 782 * This function is called by the TTY module when the 783 * SLIP line discipline is called for. Because we are 784 * sure the tty line exists, we only have to link it to 785 * a free SLIP channel... 786 * 787 * Called in process context serialized from other ldisc calls. 788 */ 789 790static int slip_open(struct tty_struct *tty) 791{ 792 struct slip *sl; 793 int err; 794 795 if (!capable(CAP_NET_ADMIN)) 796 return -EPERM; 797 798 if (tty->ops->write == NULL) 799 return -EOPNOTSUPP; 800 801 /* RTnetlink lock is misused here to serialize concurrent 802 opens of slip channels. There are better ways, but it is 803 the simplest one. 804 */ 805 rtnl_lock(); 806 807 /* Collect hanged up channels. */ 808 sl_sync(); 809 810 sl = tty->disc_data; 811 812 err = -EEXIST; 813 /* First make sure we're not already connected. */ 814 if (sl && sl->magic == SLIP_MAGIC) 815 goto err_exit; 816 817 /* OK. Find a free SLIP channel to use. */ 818 err = -ENFILE; 819 sl = sl_alloc(tty_devnum(tty)); 820 if (sl == NULL) 821 goto err_exit; 822 823 sl->tty = tty; 824 tty->disc_data = sl; 825 sl->line = tty_devnum(tty); 826 sl->pid = current->pid; 827 828 if (!test_bit(SLF_INUSE, &sl->flags)) { 829 /* Perform the low-level SLIP initialization. */ 830 err = sl_alloc_bufs(sl, SL_MTU); 831 if (err) 832 goto err_free_chan; 833 834 set_bit(SLF_INUSE, &sl->flags); 835 836 err = register_netdevice(sl->dev); 837 if (err) 838 goto err_free_bufs; 839 } 840 841#ifdef CONFIG_SLIP_SMART 842 if (sl->keepalive) { 843 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 844 add_timer(&sl->keepalive_timer); 845 } 846 if (sl->outfill) { 847 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 848 add_timer(&sl->outfill_timer); 849 } 850#endif 851 852 /* Done. We have linked the TTY line to a channel. */ 853 rtnl_unlock(); 854 tty->receive_room = 65536; /* We don't flow control */ 855 return sl->dev->base_addr; 856 857err_free_bufs: 858 sl_free_bufs(sl); 859 860err_free_chan: 861 sl->tty = NULL; 862 tty->disc_data = NULL; 863 clear_bit(SLF_INUSE, &sl->flags); 864 865err_exit: 866 rtnl_unlock(); 867 868 /* Count references from TTY module */ 869 return err; 870} 871 872/* 873 * Close down a SLIP channel. 874 * This means flushing out any pending queues, and then returning. This 875 * call is serialized against other ldisc functions. 876 * 877 * We also use this method fo a hangup event 878 */ 879 880static void slip_close(struct tty_struct *tty) 881{ 882 struct slip *sl = tty->disc_data; 883 884 /* First make sure we're connected. */ 885 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 886 return; 887 888 tty->disc_data = NULL; 889 sl->tty = NULL; 890 if (!sl->leased) 891 sl->line = 0; 892 893 /* VSV = very important to remove timers */ 894#ifdef CONFIG_SLIP_SMART 895 del_timer_sync(&sl->keepalive_timer); 896 del_timer_sync(&sl->outfill_timer); 897#endif 898 /* Flush network side */ 899 unregister_netdev(sl->dev); 900 /* This will complete via sl_free_netdev */ 901} 902 903static int slip_hangup(struct tty_struct *tty) 904{ 905 slip_close(tty); 906 return 0; 907} 908 /************************************************************************ 909 * STANDARD SLIP ENCAPSULATION * 910 ************************************************************************/ 911 912static int slip_esc(unsigned char *s, unsigned char *d, int len) 913{ 914 unsigned char *ptr = d; 915 unsigned char c; 916 917 /* 918 * Send an initial END character to flush out any 919 * data that may have accumulated in the receiver 920 * due to line noise. 921 */ 922 923 *ptr++ = END; 924 925 /* 926 * For each byte in the packet, send the appropriate 927 * character sequence, according to the SLIP protocol. 928 */ 929 930 while (len-- > 0) { 931 switch (c = *s++) { 932 case END: 933 *ptr++ = ESC; 934 *ptr++ = ESC_END; 935 break; 936 case ESC: 937 *ptr++ = ESC; 938 *ptr++ = ESC_ESC; 939 break; 940 default: 941 *ptr++ = c; 942 break; 943 } 944 } 945 *ptr++ = END; 946 return (ptr - d); 947} 948 949static void slip_unesc(struct slip *sl, unsigned char s) 950{ 951 952 switch (s) { 953 case END: 954#ifdef CONFIG_SLIP_SMART 955 /* drop keeptest bit = VSV */ 956 if (test_bit(SLF_KEEPTEST, &sl->flags)) 957 clear_bit(SLF_KEEPTEST, &sl->flags); 958#endif 959 960 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 961 (sl->rcount > 2)) 962 sl_bump(sl); 963 clear_bit(SLF_ESCAPE, &sl->flags); 964 sl->rcount = 0; 965 return; 966 967 case ESC: 968 set_bit(SLF_ESCAPE, &sl->flags); 969 return; 970 case ESC_ESC: 971 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 972 s = ESC; 973 break; 974 case ESC_END: 975 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 976 s = END; 977 break; 978 } 979 if (!test_bit(SLF_ERROR, &sl->flags)) { 980 if (sl->rcount < sl->buffsize) { 981 sl->rbuff[sl->rcount++] = s; 982 return; 983 } 984 sl->rx_over_errors++; 985 set_bit(SLF_ERROR, &sl->flags); 986 } 987} 988 989 990#ifdef CONFIG_SLIP_MODE_SLIP6 991/************************************************************************ 992 * 6 BIT SLIP ENCAPSULATION * 993 ************************************************************************/ 994 995static int slip_esc6(unsigned char *s, unsigned char *d, int len) 996{ 997 unsigned char *ptr = d; 998 unsigned char c; 999 int i; 1000 unsigned short v = 0; 1001 short bits = 0; 1002 1003 /* 1004 * Send an initial END character to flush out any 1005 * data that may have accumulated in the receiver 1006 * due to line noise. 1007 */ 1008 1009 *ptr++ = 0x70; 1010 1011 /* 1012 * Encode the packet into printable ascii characters 1013 */ 1014 1015 for (i = 0; i < len; ++i) { 1016 v = (v << 8) | s[i]; 1017 bits += 8; 1018 while (bits >= 6) { 1019 bits -= 6; 1020 c = 0x30 + ((v >> bits) & 0x3F); 1021 *ptr++ = c; 1022 } 1023 } 1024 if (bits) { 1025 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1026 *ptr++ = c; 1027 } 1028 *ptr++ = 0x70; 1029 return ptr - d; 1030} 1031 1032static void slip_unesc6(struct slip *sl, unsigned char s) 1033{ 1034 unsigned char c; 1035 1036 if (s == 0x70) { 1037#ifdef CONFIG_SLIP_SMART 1038 /* drop keeptest bit = VSV */ 1039 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1040 clear_bit(SLF_KEEPTEST, &sl->flags); 1041#endif 1042 1043 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1044 (sl->rcount > 2)) 1045 sl_bump(sl); 1046 sl->rcount = 0; 1047 sl->xbits = 0; 1048 sl->xdata = 0; 1049 } else if (s >= 0x30 && s < 0x70) { 1050 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1051 sl->xbits += 6; 1052 if (sl->xbits >= 8) { 1053 sl->xbits -= 8; 1054 c = (unsigned char)(sl->xdata >> sl->xbits); 1055 if (!test_bit(SLF_ERROR, &sl->flags)) { 1056 if (sl->rcount < sl->buffsize) { 1057 sl->rbuff[sl->rcount++] = c; 1058 return; 1059 } 1060 sl->rx_over_errors++; 1061 set_bit(SLF_ERROR, &sl->flags); 1062 } 1063 } 1064 } 1065} 1066#endif /* CONFIG_SLIP_MODE_SLIP6 */ 1067 1068/* Perform I/O control on an active SLIP channel. */ 1069static int slip_ioctl(struct tty_struct *tty, struct file *file, 1070 unsigned int cmd, unsigned long arg) 1071{ 1072 struct slip *sl = tty->disc_data; 1073 unsigned int tmp; 1074 int __user *p = (int __user *)arg; 1075 1076 /* First make sure we're connected. */ 1077 if (!sl || sl->magic != SLIP_MAGIC) 1078 return -EINVAL; 1079 1080 switch (cmd) { 1081 case SIOCGIFNAME: 1082 tmp = strlen(sl->dev->name) + 1; 1083 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1084 return -EFAULT; 1085 return 0; 1086 1087 case SIOCGIFENCAP: 1088 if (put_user(sl->mode, p)) 1089 return -EFAULT; 1090 return 0; 1091 1092 case SIOCSIFENCAP: 1093 if (get_user(tmp, p)) 1094 return -EFAULT; 1095#ifndef SL_INCLUDE_CSLIP 1096 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1097 return -EINVAL; 1098#else 1099 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1100 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1101 /* return -EINVAL; */ 1102 tmp &= ~SL_MODE_ADAPTIVE; 1103#endif 1104#ifndef CONFIG_SLIP_MODE_SLIP6 1105 if (tmp & SL_MODE_SLIP6) 1106 return -EINVAL; 1107#endif 1108 sl->mode = tmp; 1109 sl->dev->type = ARPHRD_SLIP + sl->mode; 1110 return 0; 1111 1112 case SIOCSIFHWADDR: 1113 return -EINVAL; 1114 1115#ifdef CONFIG_SLIP_SMART 1116 /* VSV changes start here */ 1117 case SIOCSKEEPALIVE: 1118 if (get_user(tmp, p)) 1119 return -EFAULT; 1120 if (tmp > 255) /* max for unchar */ 1121 return -EINVAL; 1122 1123 spin_lock_bh(&sl->lock); 1124 if (!sl->tty) { 1125 spin_unlock_bh(&sl->lock); 1126 return -ENODEV; 1127 } 1128 sl->keepalive = (u8)tmp; 1129 if (sl->keepalive != 0) { 1130 mod_timer(&sl->keepalive_timer, 1131 jiffies + sl->keepalive * HZ); 1132 set_bit(SLF_KEEPTEST, &sl->flags); 1133 } else 1134 del_timer(&sl->keepalive_timer); 1135 spin_unlock_bh(&sl->lock); 1136 return 0; 1137 1138 case SIOCGKEEPALIVE: 1139 if (put_user(sl->keepalive, p)) 1140 return -EFAULT; 1141 return 0; 1142 1143 case SIOCSOUTFILL: 1144 if (get_user(tmp, p)) 1145 return -EFAULT; 1146 if (tmp > 255) /* max for unchar */ 1147 return -EINVAL; 1148 spin_lock_bh(&sl->lock); 1149 if (!sl->tty) { 1150 spin_unlock_bh(&sl->lock); 1151 return -ENODEV; 1152 } 1153 sl->outfill = (u8)tmp; 1154 if (sl->outfill != 0) { 1155 mod_timer(&sl->outfill_timer, 1156 jiffies + sl->outfill * HZ); 1157 set_bit(SLF_OUTWAIT, &sl->flags); 1158 } else 1159 del_timer(&sl->outfill_timer); 1160 spin_unlock_bh(&sl->lock); 1161 return 0; 1162 1163 case SIOCGOUTFILL: 1164 if (put_user(sl->outfill, p)) 1165 return -EFAULT; 1166 return 0; 1167 /* VSV changes end */ 1168#endif 1169 default: 1170 return tty_mode_ioctl(tty, file, cmd, arg); 1171 } 1172} 1173 1174#ifdef CONFIG_COMPAT 1175static long slip_compat_ioctl(struct tty_struct *tty, struct file *file, 1176 unsigned int cmd, unsigned long arg) 1177{ 1178 switch (cmd) { 1179 case SIOCGIFNAME: 1180 case SIOCGIFENCAP: 1181 case SIOCSIFENCAP: 1182 case SIOCSIFHWADDR: 1183 case SIOCSKEEPALIVE: 1184 case SIOCGKEEPALIVE: 1185 case SIOCSOUTFILL: 1186 case SIOCGOUTFILL: 1187 return slip_ioctl(tty, file, cmd, 1188 (unsigned long)compat_ptr(arg)); 1189 } 1190 1191 return -ENOIOCTLCMD; 1192} 1193#endif 1194 1195/* VSV changes start here */ 1196#ifdef CONFIG_SLIP_SMART 1197/* function do_ioctl called from net/core/dev.c 1198 to allow get/set outfill/keepalive parameter 1199 by ifconfig */ 1200 1201static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1202{ 1203 struct slip *sl = netdev_priv(dev); 1204 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1205 1206 if (sl == NULL) /* Allocation failed ?? */ 1207 return -ENODEV; 1208 1209 spin_lock_bh(&sl->lock); 1210 1211 if (!sl->tty) { 1212 spin_unlock_bh(&sl->lock); 1213 return -ENODEV; 1214 } 1215 1216 switch (cmd) { 1217 case SIOCSKEEPALIVE: 1218 /* max for unchar */ 1219 if ((unsigned)*p > 255) { 1220 spin_unlock_bh(&sl->lock); 1221 return -EINVAL; 1222 } 1223 sl->keepalive = (u8)*p; 1224 if (sl->keepalive != 0) { 1225 sl->keepalive_timer.expires = 1226 jiffies + sl->keepalive * HZ; 1227 mod_timer(&sl->keepalive_timer, 1228 jiffies + sl->keepalive * HZ); 1229 set_bit(SLF_KEEPTEST, &sl->flags); 1230 } else 1231 del_timer(&sl->keepalive_timer); 1232 break; 1233 1234 case SIOCGKEEPALIVE: 1235 *p = sl->keepalive; 1236 break; 1237 1238 case SIOCSOUTFILL: 1239 if ((unsigned)*p > 255) { /* max for unchar */ 1240 spin_unlock_bh(&sl->lock); 1241 return -EINVAL; 1242 } 1243 sl->outfill = (u8)*p; 1244 if (sl->outfill != 0) { 1245 mod_timer(&sl->outfill_timer, 1246 jiffies + sl->outfill * HZ); 1247 set_bit(SLF_OUTWAIT, &sl->flags); 1248 } else 1249 del_timer(&sl->outfill_timer); 1250 break; 1251 1252 case SIOCGOUTFILL: 1253 *p = sl->outfill; 1254 break; 1255 1256 case SIOCSLEASE: 1257 /* Resolve race condition, when ioctl'ing hanged up 1258 and opened by another process device. 1259 */ 1260 if (sl->tty != current->signal->tty && 1261 sl->pid != current->pid) { 1262 spin_unlock_bh(&sl->lock); 1263 return -EPERM; 1264 } 1265 sl->leased = 0; 1266 if (*p) 1267 sl->leased = 1; 1268 break; 1269 1270 case SIOCGLEASE: 1271 *p = sl->leased; 1272 } 1273 spin_unlock_bh(&sl->lock); 1274 return 0; 1275} 1276#endif 1277/* VSV changes end */ 1278 1279static struct tty_ldisc_ops sl_ldisc = { 1280 .owner = THIS_MODULE, 1281 .magic = TTY_LDISC_MAGIC, 1282 .name = "slip", 1283 .open = slip_open, 1284 .close = slip_close, 1285 .hangup = slip_hangup, 1286 .ioctl = slip_ioctl, 1287#ifdef CONFIG_COMPAT 1288 .compat_ioctl = slip_compat_ioctl, 1289#endif 1290 .receive_buf = slip_receive_buf, 1291 .write_wakeup = slip_write_wakeup, 1292}; 1293 1294static int __init slip_init(void) 1295{ 1296 int status; 1297 1298 if (slip_maxdev < 4) 1299 slip_maxdev = 4; /* Sanity */ 1300 1301 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" 1302#ifdef CONFIG_SLIP_MODE_SLIP6 1303 " (6 bit encapsulation enabled)" 1304#endif 1305 ".\n", 1306 SLIP_VERSION, slip_maxdev); 1307#if defined(SL_INCLUDE_CSLIP) 1308 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); 1309#endif 1310#ifdef CONFIG_SLIP_SMART 1311 printk(KERN_INFO "SLIP linefill/keepalive option.\n"); 1312#endif 1313 1314 slip_devs = kzalloc(sizeof(struct net_device *)*slip_maxdev, 1315 GFP_KERNEL); 1316 if (!slip_devs) { 1317 printk(KERN_ERR "SLIP: Can't allocate slip devices array.\n"); 1318 return -ENOMEM; 1319 } 1320 1321 /* Fill in our line protocol discipline, and register it */ 1322 status = tty_register_ldisc(N_SLIP, &sl_ldisc); 1323 if (status != 0) { 1324 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); 1325 kfree(slip_devs); 1326 } 1327 return status; 1328} 1329 1330static void __exit slip_exit(void) 1331{ 1332 int i; 1333 struct net_device *dev; 1334 struct slip *sl; 1335 unsigned long timeout = jiffies + HZ; 1336 int busy = 0; 1337 1338 if (slip_devs == NULL) 1339 return; 1340 1341 /* First of all: check for active disciplines and hangup them. 1342 */ 1343 do { 1344 if (busy) 1345 msleep_interruptible(100); 1346 1347 busy = 0; 1348 for (i = 0; i < slip_maxdev; i++) { 1349 dev = slip_devs[i]; 1350 if (!dev) 1351 continue; 1352 sl = netdev_priv(dev); 1353 spin_lock_bh(&sl->lock); 1354 if (sl->tty) { 1355 busy++; 1356 tty_hangup(sl->tty); 1357 } 1358 spin_unlock_bh(&sl->lock); 1359 } 1360 } while (busy && time_before(jiffies, timeout)); 1361 1362 1363 for (i = 0; i < slip_maxdev; i++) { 1364 dev = slip_devs[i]; 1365 if (!dev) 1366 continue; 1367 slip_devs[i] = NULL; 1368 1369 sl = netdev_priv(dev); 1370 if (sl->tty) { 1371 printk(KERN_ERR "%s: tty discipline still running\n", 1372 dev->name); 1373 /* Intentionally leak the control block. */ 1374 dev->destructor = NULL; 1375 } 1376 1377 unregister_netdev(dev); 1378 } 1379 1380 kfree(slip_devs); 1381 slip_devs = NULL; 1382 1383 i = tty_unregister_ldisc(N_SLIP); 1384 if (i != 0) 1385 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1386} 1387 1388module_init(slip_init); 1389module_exit(slip_exit); 1390 1391#ifdef CONFIG_SLIP_SMART 1392/* 1393 * This is start of the code for multislip style line checking 1394 * added by Stanislav Voronyi. All changes before marked VSV 1395 */ 1396 1397static void sl_outfill(unsigned long sls) 1398{ 1399 struct slip *sl = (struct slip *)sls; 1400 1401 spin_lock(&sl->lock); 1402 1403 if (sl->tty == NULL) 1404 goto out; 1405 1406 if (sl->outfill) { 1407 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1408 /* no packets were transmitted, do outfill */ 1409#ifdef CONFIG_SLIP_MODE_SLIP6 1410 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1411#else 1412 unsigned char s = END; 1413#endif 1414 /* put END into tty queue. Is it right ??? */ 1415 if (!netif_queue_stopped(sl->dev)) { 1416 /* if device busy no outfill */ 1417 sl->tty->ops->write(sl->tty, &s, 1); 1418 } 1419 } else 1420 set_bit(SLF_OUTWAIT, &sl->flags); 1421 1422 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1423 } 1424out: 1425 spin_unlock(&sl->lock); 1426} 1427 1428static void sl_keepalive(unsigned long sls) 1429{ 1430 struct slip *sl = (struct slip *)sls; 1431 1432 spin_lock(&sl->lock); 1433 1434 if (sl->tty == NULL) 1435 goto out; 1436 1437 if (sl->keepalive) { 1438 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1439 /* keepalive still high :(, we must hangup */ 1440 if (sl->outfill) 1441 /* outfill timer must be deleted too */ 1442 (void)del_timer(&sl->outfill_timer); 1443 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1444 /* this must hangup tty & close slip */ 1445 tty_hangup(sl->tty); 1446 /* I think we need not something else */ 1447 goto out; 1448 } else 1449 set_bit(SLF_KEEPTEST, &sl->flags); 1450 1451 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1452 } 1453out: 1454 spin_unlock(&sl->lock); 1455} 1456 1457#endif 1458MODULE_LICENSE("GPL"); 1459MODULE_ALIAS_LDISC(N_SLIP); 1460