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