1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * slip.c This module implements the SLIP protocol for kernel-based 4 * devices like TTY. It interfaces between a raw TTY, and the 5 * kernel's INET protocol layers. 6 * 7 * Version: @(#)slip.c 0.8.3 12/24/94 8 * 9 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk> 10 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> 11 * 12 * Fixes: 13 * Alan Cox : Sanity checks and avoid tx overruns. 14 * Has a new sl->mtu field. 15 * Alan Cox : Found cause of overrun. ifconfig sl0 16 * mtu upwards. Driver now spots this 17 * and grows/shrinks its buffers(hack!). 18 * Memory leak if you run out of memory 19 * setting up a slip driver fixed. 20 * Matt Dillon : Printable slip (borrowed from NET2E) 21 * Pauline Middelink : Slip driver fixes. 22 * Alan Cox : Honours the old SL_COMPRESSED flag 23 * Alan Cox : KISS AX.25 and AXUI IP support 24 * Michael Riepe : Automatic CSLIP recognition added 25 * Charles Hedrick : CSLIP header length problem fix. 26 * Alan Cox : Corrected non-IP cases of the above. 27 * Alan Cox : Now uses hardware type as per FvK. 28 * Alan Cox : Default to 192.168.0.0 (RFC 1597) 29 * A.N.Kuznetsov : dev_tint() recursion fix. 30 * Dmitry Gorodchanin : SLIP memory leaks 31 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver 32 * buffering from 4096 to 256 bytes. 33 * Improving SLIP response time. 34 * CONFIG_SLIP_MODE_SLIP6. 35 * ifconfig sl? up & down now works 36 * correctly. 37 * Modularization. 38 * Alan Cox : Oops - fix AX.25 buffer lengths 39 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP 40 * statistics. Include CSLIP code only 41 * if it really needed. 42 * Alan Cox : Free slhc buffers in the right place. 43 * Alan Cox : Allow for digipeated IP over AX.25 44 * Matti Aarnio : Dynamic SLIP devices, with ideas taken 45 * from Jim Freeman's <jfree@caldera.com> 46 * dynamic PPP devices. We do NOT kfree() 47 * device entries, just reg./unreg. them 48 * as they are needed. We kfree() them 49 * at module cleanup. 50 * With MODULE-loading ``insmod'', user 51 * can issue parameter: slip_maxdev=1024 52 * (Or how much he/she wants.. Default 53 * is 256) 54 * Stanislav Voronyi : Slip line checking, with ideas taken 55 * from multislip BSDI driver which was 56 * written by Igor Chechik, RELCOM Corp. 57 * Only algorithms have been ported to 58 * Linux SLIP driver. 59 * Vitaly E. Lavrov : Sane behaviour on tty hangup. 60 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice 61 * modules. 62 */ 63 64 #define SL_CHECK_TRANSMIT 65 #include <linux/module.h> 66 #include <linux/moduleparam.h> 67 68 #include <linux/uaccess.h> 69 #include <linux/bitops.h> 70 #include <linux/sched/signal.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/delay.h> 84 #include <linux/init.h> 85 #include <linux/slab.h> 86 #include <linux/workqueue.h> 87 #include "slip.h" 88 #ifdef CONFIG_INET 89 #include <linux/ip.h> 90 #include <linux/tcp.h> 91 #include <net/slhc_vj.h> 92 #endif 93 94 #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY" 95 96 static struct net_device **slip_devs; 97 98 static int slip_maxdev = SL_NRUNIT; 99 module_param(slip_maxdev, int, 0); 100 MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices"); 101 102 static int slip_esc(unsigned char *p, unsigned char *d, int len); 103 static void slip_unesc(struct slip *sl, unsigned char c); 104 #ifdef CONFIG_SLIP_MODE_SLIP6 105 static int slip_esc6(unsigned char *p, unsigned char *d, int len); 106 static void slip_unesc6(struct slip *sl, unsigned char c); 107 #endif 108 #ifdef CONFIG_SLIP_SMART 109 static void sl_keepalive(struct timer_list *t); 110 static void sl_outfill(struct timer_list *t); 111 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd); 112 #endif 113 114 /******************************** 115 * Buffer administration routines: 116 * sl_alloc_bufs() 117 * sl_free_bufs() 118 * sl_realloc_bufs() 119 * 120 * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because 121 * sl_realloc_bufs provides strong atomicity and reallocation 122 * on actively running device. 123 *********************************/ 124 125 /* 126 Allocate channel buffers. 127 */ 128 129 static int sl_alloc_bufs(struct slip *sl, int mtu) 130 { 131 int err = -ENOBUFS; 132 unsigned long len; 133 char *rbuff = NULL; 134 char *xbuff = NULL; 135 #ifdef SL_INCLUDE_CSLIP 136 char *cbuff = NULL; 137 struct slcompress *slcomp = NULL; 138 #endif 139 140 /* 141 * Allocate the SLIP frame buffers: 142 * 143 * rbuff Receive buffer. 144 * xbuff Transmit buffer. 145 * cbuff Temporary compression buffer. 146 */ 147 len = mtu * 2; 148 149 /* 150 * allow for arrival of larger UDP packets, even if we say not to 151 * also fixes a bug in which SunOS sends 512-byte packets even with 152 * an MSS of 128 153 */ 154 if (len < 576 * 2) 155 len = 576 * 2; 156 rbuff = kmalloc(len + 4, GFP_KERNEL); 157 if (rbuff == NULL) 158 goto err_exit; 159 xbuff = kmalloc(len + 4, GFP_KERNEL); 160 if (xbuff == NULL) 161 goto err_exit; 162 #ifdef SL_INCLUDE_CSLIP 163 cbuff = kmalloc(len + 4, GFP_KERNEL); 164 if (cbuff == NULL) 165 goto err_exit; 166 slcomp = slhc_init(16, 16); 167 if (IS_ERR(slcomp)) 168 goto err_exit; 169 #endif 170 spin_lock_bh(&sl->lock); 171 if (sl->tty == NULL) { 172 spin_unlock_bh(&sl->lock); 173 err = -ENODEV; 174 goto err_exit; 175 } 176 sl->mtu = mtu; 177 sl->buffsize = len; 178 sl->rcount = 0; 179 sl->xleft = 0; 180 rbuff = xchg(&sl->rbuff, rbuff); 181 xbuff = xchg(&sl->xbuff, xbuff); 182 #ifdef SL_INCLUDE_CSLIP 183 cbuff = xchg(&sl->cbuff, cbuff); 184 slcomp = xchg(&sl->slcomp, slcomp); 185 #endif 186 #ifdef CONFIG_SLIP_MODE_SLIP6 187 sl->xdata = 0; 188 sl->xbits = 0; 189 #endif 190 spin_unlock_bh(&sl->lock); 191 err = 0; 192 193 /* Cleanup */ 194 err_exit: 195 #ifdef SL_INCLUDE_CSLIP 196 kfree(cbuff); 197 slhc_free(slcomp); 198 #endif 199 kfree(xbuff); 200 kfree(rbuff); 201 return err; 202 } 203 204 /* Free a SLIP channel buffers. */ 205 static void sl_free_bufs(struct slip *sl) 206 { 207 /* Free all SLIP frame buffers. */ 208 kfree(xchg(&sl->rbuff, NULL)); 209 kfree(xchg(&sl->xbuff, NULL)); 210 #ifdef SL_INCLUDE_CSLIP 211 kfree(xchg(&sl->cbuff, NULL)); 212 slhc_free(xchg(&sl->slcomp, NULL)); 213 #endif 214 } 215 216 /* 217 Reallocate slip channel buffers. 218 */ 219 220 static int sl_realloc_bufs(struct slip *sl, int mtu) 221 { 222 int err = 0; 223 struct net_device *dev = sl->dev; 224 unsigned char *xbuff, *rbuff; 225 #ifdef SL_INCLUDE_CSLIP 226 unsigned char *cbuff; 227 #endif 228 int len = mtu * 2; 229 230 /* 231 * allow for arrival of larger UDP packets, even if we say not to 232 * also fixes a bug in which SunOS sends 512-byte packets even with 233 * an MSS of 128 234 */ 235 if (len < 576 * 2) 236 len = 576 * 2; 237 238 xbuff = kmalloc(len + 4, GFP_ATOMIC); 239 rbuff = kmalloc(len + 4, GFP_ATOMIC); 240 #ifdef SL_INCLUDE_CSLIP 241 cbuff = kmalloc(len + 4, GFP_ATOMIC); 242 #endif 243 244 245 #ifdef SL_INCLUDE_CSLIP 246 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) { 247 #else 248 if (xbuff == NULL || rbuff == NULL) { 249 #endif 250 if (mtu > sl->mtu) { 251 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n", 252 dev->name); 253 err = -ENOBUFS; 254 } 255 goto done; 256 } 257 spin_lock_bh(&sl->lock); 258 259 err = -ENODEV; 260 if (sl->tty == NULL) 261 goto done_on_bh; 262 263 xbuff = xchg(&sl->xbuff, xbuff); 264 rbuff = xchg(&sl->rbuff, rbuff); 265 #ifdef SL_INCLUDE_CSLIP 266 cbuff = xchg(&sl->cbuff, cbuff); 267 #endif 268 if (sl->xleft) { 269 if (sl->xleft <= len) { 270 memcpy(sl->xbuff, sl->xhead, sl->xleft); 271 } else { 272 sl->xleft = 0; 273 dev->stats.tx_dropped++; 274 } 275 } 276 sl->xhead = sl->xbuff; 277 278 if (sl->rcount) { 279 if (sl->rcount <= len) { 280 memcpy(sl->rbuff, rbuff, sl->rcount); 281 } else { 282 sl->rcount = 0; 283 dev->stats.rx_over_errors++; 284 set_bit(SLF_ERROR, &sl->flags); 285 } 286 } 287 sl->mtu = mtu; 288 dev->mtu = mtu; 289 sl->buffsize = len; 290 err = 0; 291 292 done_on_bh: 293 spin_unlock_bh(&sl->lock); 294 295 done: 296 kfree(xbuff); 297 kfree(rbuff); 298 #ifdef SL_INCLUDE_CSLIP 299 kfree(cbuff); 300 #endif 301 return err; 302 } 303 304 305 /* Set the "sending" flag. This must be atomic hence the set_bit. */ 306 static inline void sl_lock(struct slip *sl) 307 { 308 netif_stop_queue(sl->dev); 309 } 310 311 312 /* Clear the "sending" flag. This must be atomic, hence the ASM. */ 313 static inline void sl_unlock(struct slip *sl) 314 { 315 netif_wake_queue(sl->dev); 316 } 317 318 /* Send one completely decapsulated IP datagram to the IP layer. */ 319 static void sl_bump(struct slip *sl) 320 { 321 struct net_device *dev = sl->dev; 322 struct sk_buff *skb; 323 int count; 324 325 count = sl->rcount; 326 #ifdef SL_INCLUDE_CSLIP 327 if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) { 328 unsigned char c = sl->rbuff[0]; 329 if (c & SL_TYPE_COMPRESSED_TCP) { 330 /* ignore compressed packets when CSLIP is off */ 331 if (!(sl->mode & SL_MODE_CSLIP)) { 332 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name); 333 return; 334 } 335 /* make sure we've reserved enough space for uncompress 336 to use */ 337 if (count + 80 > sl->buffsize) { 338 dev->stats.rx_over_errors++; 339 return; 340 } 341 count = slhc_uncompress(sl->slcomp, sl->rbuff, count); 342 if (count <= 0) 343 return; 344 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) { 345 if (!(sl->mode & SL_MODE_CSLIP)) { 346 /* turn on header compression */ 347 sl->mode |= SL_MODE_CSLIP; 348 sl->mode &= ~SL_MODE_ADAPTIVE; 349 printk(KERN_INFO "%s: header compression turned on\n", dev->name); 350 } 351 sl->rbuff[0] &= 0x4f; 352 if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0) 353 return; 354 } 355 } 356 #endif /* SL_INCLUDE_CSLIP */ 357 358 dev->stats.rx_bytes += count; 359 360 skb = dev_alloc_skb(count); 361 if (skb == NULL) { 362 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name); 363 dev->stats.rx_dropped++; 364 return; 365 } 366 skb->dev = dev; 367 skb_put_data(skb, sl->rbuff, count); 368 skb_reset_mac_header(skb); 369 skb->protocol = htons(ETH_P_IP); 370 netif_rx_ni(skb); 371 dev->stats.rx_packets++; 372 } 373 374 /* Encapsulate one IP datagram and stuff into a TTY queue. */ 375 static void sl_encaps(struct slip *sl, unsigned char *icp, int len) 376 { 377 unsigned char *p; 378 int actual, count; 379 380 if (len > sl->mtu) { /* Sigh, shouldn't occur BUT ... */ 381 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name); 382 sl->dev->stats.tx_dropped++; 383 sl_unlock(sl); 384 return; 385 } 386 387 p = icp; 388 #ifdef SL_INCLUDE_CSLIP 389 if (sl->mode & SL_MODE_CSLIP) 390 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1); 391 #endif 392 #ifdef CONFIG_SLIP_MODE_SLIP6 393 if (sl->mode & SL_MODE_SLIP6) 394 count = slip_esc6(p, sl->xbuff, len); 395 else 396 #endif 397 count = slip_esc(p, sl->xbuff, len); 398 399 /* Order of next two lines is *very* important. 400 * When we are sending a little amount of data, 401 * the transfer may be completed inside the ops->write() 402 * routine, because it's running with interrupts enabled. 403 * In this case we *never* got WRITE_WAKEUP event, 404 * if we did not request it before write operation. 405 * 14 Oct 1994 Dmitry Gorodchanin. 406 */ 407 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 408 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count); 409 #ifdef SL_CHECK_TRANSMIT 410 netif_trans_update(sl->dev); 411 #endif 412 sl->xleft = count - actual; 413 sl->xhead = sl->xbuff + actual; 414 #ifdef CONFIG_SLIP_SMART 415 /* VSV */ 416 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */ 417 #endif 418 } 419 420 /* Write out any remaining transmit buffer. Scheduled when tty is writable */ 421 static void slip_transmit(struct work_struct *work) 422 { 423 struct slip *sl = container_of(work, struct slip, tx_work); 424 int actual; 425 426 spin_lock_bh(&sl->lock); 427 /* First make sure we're connected. */ 428 if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) { 429 spin_unlock_bh(&sl->lock); 430 return; 431 } 432 433 if (sl->xleft <= 0) { 434 /* Now serial buffer is almost free & we can start 435 * transmission of another packet */ 436 sl->dev->stats.tx_packets++; 437 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 438 spin_unlock_bh(&sl->lock); 439 sl_unlock(sl); 440 return; 441 } 442 443 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft); 444 sl->xleft -= actual; 445 sl->xhead += actual; 446 spin_unlock_bh(&sl->lock); 447 } 448 449 /* 450 * Called by the driver when there's room for more data. 451 * Schedule the transmit. 452 */ 453 static void slip_write_wakeup(struct tty_struct *tty) 454 { 455 struct slip *sl = tty->disc_data; 456 457 schedule_work(&sl->tx_work); 458 } 459 460 static void sl_tx_timeout(struct net_device *dev) 461 { 462 struct slip *sl = netdev_priv(dev); 463 464 spin_lock(&sl->lock); 465 466 if (netif_queue_stopped(dev)) { 467 if (!netif_running(dev)) 468 goto out; 469 470 /* May be we must check transmitter timeout here ? 471 * 14 Oct 1994 Dmitry Gorodchanin. 472 */ 473 #ifdef SL_CHECK_TRANSMIT 474 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) { 475 /* 20 sec timeout not reached */ 476 goto out; 477 } 478 printk(KERN_WARNING "%s: transmit timed out, %s?\n", 479 dev->name, 480 (tty_chars_in_buffer(sl->tty) || sl->xleft) ? 481 "bad line quality" : "driver error"); 482 sl->xleft = 0; 483 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 484 sl_unlock(sl); 485 #endif 486 } 487 out: 488 spin_unlock(&sl->lock); 489 } 490 491 492 /* Encapsulate an IP datagram and kick it into a TTY queue. */ 493 static netdev_tx_t 494 sl_xmit(struct sk_buff *skb, struct net_device *dev) 495 { 496 struct slip *sl = netdev_priv(dev); 497 498 spin_lock(&sl->lock); 499 if (!netif_running(dev)) { 500 spin_unlock(&sl->lock); 501 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name); 502 dev_kfree_skb(skb); 503 return NETDEV_TX_OK; 504 } 505 if (sl->tty == NULL) { 506 spin_unlock(&sl->lock); 507 dev_kfree_skb(skb); 508 return NETDEV_TX_OK; 509 } 510 511 sl_lock(sl); 512 dev->stats.tx_bytes += skb->len; 513 sl_encaps(sl, skb->data, skb->len); 514 spin_unlock(&sl->lock); 515 516 dev_kfree_skb(skb); 517 return NETDEV_TX_OK; 518 } 519 520 521 /****************************************** 522 * Routines looking at netdevice side. 523 ******************************************/ 524 525 /* Netdevice UP -> DOWN routine */ 526 527 static int 528 sl_close(struct net_device *dev) 529 { 530 struct slip *sl = netdev_priv(dev); 531 532 spin_lock_bh(&sl->lock); 533 if (sl->tty) 534 /* TTY discipline is running. */ 535 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 536 netif_stop_queue(dev); 537 sl->rcount = 0; 538 sl->xleft = 0; 539 spin_unlock_bh(&sl->lock); 540 541 return 0; 542 } 543 544 /* Netdevice DOWN -> UP routine */ 545 546 static int sl_open(struct net_device *dev) 547 { 548 struct slip *sl = netdev_priv(dev); 549 550 if (sl->tty == NULL) 551 return -ENODEV; 552 553 sl->flags &= (1 << SLF_INUSE); 554 netif_start_queue(dev); 555 return 0; 556 } 557 558 /* Netdevice change MTU request */ 559 560 static int sl_change_mtu(struct net_device *dev, int new_mtu) 561 { 562 struct slip *sl = netdev_priv(dev); 563 564 return sl_realloc_bufs(sl, new_mtu); 565 } 566 567 /* Netdevice get statistics request */ 568 569 static void 570 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 571 { 572 struct net_device_stats *devstats = &dev->stats; 573 #ifdef SL_INCLUDE_CSLIP 574 struct slip *sl = netdev_priv(dev); 575 struct slcompress *comp = sl->slcomp; 576 #endif 577 stats->rx_packets = devstats->rx_packets; 578 stats->tx_packets = devstats->tx_packets; 579 stats->rx_bytes = devstats->rx_bytes; 580 stats->tx_bytes = devstats->tx_bytes; 581 stats->rx_dropped = devstats->rx_dropped; 582 stats->tx_dropped = devstats->tx_dropped; 583 stats->tx_errors = devstats->tx_errors; 584 stats->rx_errors = devstats->rx_errors; 585 stats->rx_over_errors = devstats->rx_over_errors; 586 587 #ifdef SL_INCLUDE_CSLIP 588 if (comp) { 589 /* Generic compressed statistics */ 590 stats->rx_compressed = comp->sls_i_compressed; 591 stats->tx_compressed = comp->sls_o_compressed; 592 593 /* Are we really still needs this? */ 594 stats->rx_fifo_errors += comp->sls_i_compressed; 595 stats->rx_dropped += comp->sls_i_tossed; 596 stats->tx_fifo_errors += comp->sls_o_compressed; 597 stats->collisions += comp->sls_o_misses; 598 } 599 #endif 600 } 601 602 /* Netdevice register callback */ 603 604 static int sl_init(struct net_device *dev) 605 { 606 struct slip *sl = netdev_priv(dev); 607 608 /* 609 * Finish setting up the DEVICE info. 610 */ 611 612 dev->mtu = sl->mtu; 613 dev->type = ARPHRD_SLIP + sl->mode; 614 #ifdef SL_CHECK_TRANSMIT 615 dev->watchdog_timeo = 20*HZ; 616 #endif 617 return 0; 618 } 619 620 621 static void sl_uninit(struct net_device *dev) 622 { 623 struct slip *sl = netdev_priv(dev); 624 625 sl_free_bufs(sl); 626 } 627 628 /* Hook the destructor so we can free slip devices at the right point in time */ 629 static void sl_free_netdev(struct net_device *dev) 630 { 631 int i = dev->base_addr; 632 633 slip_devs[i] = NULL; 634 } 635 636 static const struct net_device_ops sl_netdev_ops = { 637 .ndo_init = sl_init, 638 .ndo_uninit = sl_uninit, 639 .ndo_open = sl_open, 640 .ndo_stop = sl_close, 641 .ndo_start_xmit = sl_xmit, 642 .ndo_get_stats64 = sl_get_stats64, 643 .ndo_change_mtu = sl_change_mtu, 644 .ndo_tx_timeout = sl_tx_timeout, 645 #ifdef CONFIG_SLIP_SMART 646 .ndo_do_ioctl = sl_ioctl, 647 #endif 648 }; 649 650 651 static void sl_setup(struct net_device *dev) 652 { 653 dev->netdev_ops = &sl_netdev_ops; 654 dev->needs_free_netdev = true; 655 dev->priv_destructor = sl_free_netdev; 656 657 dev->hard_header_len = 0; 658 dev->addr_len = 0; 659 dev->tx_queue_len = 10; 660 661 /* MTU range: 68 - 65534 */ 662 dev->min_mtu = 68; 663 dev->max_mtu = 65534; 664 665 /* New-style flags. */ 666 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 667 } 668 669 /****************************************** 670 Routines looking at TTY side. 671 ******************************************/ 672 673 674 /* 675 * Handle the 'receiver data ready' interrupt. 676 * This function is called by the 'tty_io' module in the kernel when 677 * a block of SLIP data has been received, which can now be decapsulated 678 * and sent on to some IP layer for further processing. This will not 679 * be re-entered while running but other ldisc functions may be called 680 * in parallel 681 */ 682 683 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 684 char *fp, int count) 685 { 686 struct slip *sl = tty->disc_data; 687 688 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 689 return; 690 691 /* Read the characters out of the buffer */ 692 while (count--) { 693 if (fp && *fp++) { 694 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 695 sl->dev->stats.rx_errors++; 696 cp++; 697 continue; 698 } 699 #ifdef CONFIG_SLIP_MODE_SLIP6 700 if (sl->mode & SL_MODE_SLIP6) 701 slip_unesc6(sl, *cp++); 702 else 703 #endif 704 slip_unesc(sl, *cp++); 705 } 706 } 707 708 /************************************ 709 * slip_open helper routines. 710 ************************************/ 711 712 /* Collect hanged up channels */ 713 static void sl_sync(void) 714 { 715 int i; 716 struct net_device *dev; 717 struct slip *sl; 718 719 for (i = 0; i < slip_maxdev; i++) { 720 dev = slip_devs[i]; 721 if (dev == NULL) 722 break; 723 724 sl = netdev_priv(dev); 725 if (sl->tty || sl->leased) 726 continue; 727 if (dev->flags & IFF_UP) 728 dev_close(dev); 729 } 730 } 731 732 733 /* Find a free SLIP channel, and link in this `tty' line. */ 734 static struct slip *sl_alloc(void) 735 { 736 int i; 737 char name[IFNAMSIZ]; 738 struct net_device *dev = NULL; 739 struct slip *sl; 740 741 for (i = 0; i < slip_maxdev; i++) { 742 dev = slip_devs[i]; 743 if (dev == NULL) 744 break; 745 } 746 /* Sorry, too many, all slots in use */ 747 if (i >= slip_maxdev) 748 return NULL; 749 750 sprintf(name, "sl%d", i); 751 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup); 752 if (!dev) 753 return NULL; 754 755 dev->base_addr = i; 756 sl = netdev_priv(dev); 757 758 /* Initialize channel control data */ 759 sl->magic = SLIP_MAGIC; 760 sl->dev = dev; 761 spin_lock_init(&sl->lock); 762 INIT_WORK(&sl->tx_work, slip_transmit); 763 sl->mode = SL_MODE_DEFAULT; 764 #ifdef CONFIG_SLIP_SMART 765 /* initialize timer_list struct */ 766 timer_setup(&sl->keepalive_timer, sl_keepalive, 0); 767 timer_setup(&sl->outfill_timer, sl_outfill, 0); 768 #endif 769 slip_devs[i] = dev; 770 return sl; 771 } 772 773 /* 774 * Open the high-level part of the SLIP channel. 775 * This function is called by the TTY module when the 776 * SLIP line discipline is called for. Because we are 777 * sure the tty line exists, we only have to link it to 778 * a free SLIP channel... 779 * 780 * Called in process context serialized from other ldisc calls. 781 */ 782 783 static int slip_open(struct tty_struct *tty) 784 { 785 struct slip *sl; 786 int err; 787 788 if (!capable(CAP_NET_ADMIN)) 789 return -EPERM; 790 791 if (tty->ops->write == NULL) 792 return -EOPNOTSUPP; 793 794 /* RTnetlink lock is misused here to serialize concurrent 795 opens of slip channels. There are better ways, but it is 796 the simplest one. 797 */ 798 rtnl_lock(); 799 800 /* Collect hanged up channels. */ 801 sl_sync(); 802 803 sl = tty->disc_data; 804 805 err = -EEXIST; 806 /* First make sure we're not already connected. */ 807 if (sl && sl->magic == SLIP_MAGIC) 808 goto err_exit; 809 810 /* OK. Find a free SLIP channel to use. */ 811 err = -ENFILE; 812 sl = sl_alloc(); 813 if (sl == NULL) 814 goto err_exit; 815 816 sl->tty = tty; 817 tty->disc_data = sl; 818 sl->pid = current->pid; 819 820 if (!test_bit(SLF_INUSE, &sl->flags)) { 821 /* Perform the low-level SLIP initialization. */ 822 err = sl_alloc_bufs(sl, SL_MTU); 823 if (err) 824 goto err_free_chan; 825 826 set_bit(SLF_INUSE, &sl->flags); 827 828 err = register_netdevice(sl->dev); 829 if (err) 830 goto err_free_bufs; 831 } 832 833 #ifdef CONFIG_SLIP_SMART 834 if (sl->keepalive) { 835 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 836 add_timer(&sl->keepalive_timer); 837 } 838 if (sl->outfill) { 839 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 840 add_timer(&sl->outfill_timer); 841 } 842 #endif 843 844 /* Done. We have linked the TTY line to a channel. */ 845 rtnl_unlock(); 846 tty->receive_room = 65536; /* We don't flow control */ 847 848 /* TTY layer expects 0 on success */ 849 return 0; 850 851 err_free_bufs: 852 sl_free_bufs(sl); 853 854 err_free_chan: 855 sl->tty = NULL; 856 tty->disc_data = NULL; 857 clear_bit(SLF_INUSE, &sl->flags); 858 sl_free_netdev(sl->dev); 859 free_netdev(sl->dev); 860 861 err_exit: 862 rtnl_unlock(); 863 864 /* Count references from TTY module */ 865 return err; 866 } 867 868 /* 869 * Close down a SLIP channel. 870 * This means flushing out any pending queues, and then returning. This 871 * call is serialized against other ldisc functions. 872 * 873 * We also use this method fo a hangup event 874 */ 875 876 static void slip_close(struct tty_struct *tty) 877 { 878 struct slip *sl = tty->disc_data; 879 880 /* First make sure we're connected. */ 881 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 882 return; 883 884 spin_lock_bh(&sl->lock); 885 tty->disc_data = NULL; 886 sl->tty = NULL; 887 spin_unlock_bh(&sl->lock); 888 889 flush_work(&sl->tx_work); 890 891 /* VSV = very important to remove timers */ 892 #ifdef CONFIG_SLIP_SMART 893 del_timer_sync(&sl->keepalive_timer); 894 del_timer_sync(&sl->outfill_timer); 895 #endif 896 /* Flush network side */ 897 unregister_netdev(sl->dev); 898 /* This will complete via sl_free_netdev */ 899 } 900 901 static int slip_hangup(struct tty_struct *tty) 902 { 903 slip_close(tty); 904 return 0; 905 } 906 /************************************************************************ 907 * STANDARD SLIP ENCAPSULATION * 908 ************************************************************************/ 909 910 static int slip_esc(unsigned char *s, unsigned char *d, int len) 911 { 912 unsigned char *ptr = d; 913 unsigned char c; 914 915 /* 916 * Send an initial END character to flush out any 917 * data that may have accumulated in the receiver 918 * due to line noise. 919 */ 920 921 *ptr++ = END; 922 923 /* 924 * For each byte in the packet, send the appropriate 925 * character sequence, according to the SLIP protocol. 926 */ 927 928 while (len-- > 0) { 929 switch (c = *s++) { 930 case END: 931 *ptr++ = ESC; 932 *ptr++ = ESC_END; 933 break; 934 case ESC: 935 *ptr++ = ESC; 936 *ptr++ = ESC_ESC; 937 break; 938 default: 939 *ptr++ = c; 940 break; 941 } 942 } 943 *ptr++ = END; 944 return ptr - d; 945 } 946 947 static void slip_unesc(struct slip *sl, unsigned char s) 948 { 949 950 switch (s) { 951 case END: 952 #ifdef CONFIG_SLIP_SMART 953 /* drop keeptest bit = VSV */ 954 if (test_bit(SLF_KEEPTEST, &sl->flags)) 955 clear_bit(SLF_KEEPTEST, &sl->flags); 956 #endif 957 958 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 959 (sl->rcount > 2)) 960 sl_bump(sl); 961 clear_bit(SLF_ESCAPE, &sl->flags); 962 sl->rcount = 0; 963 return; 964 965 case ESC: 966 set_bit(SLF_ESCAPE, &sl->flags); 967 return; 968 case ESC_ESC: 969 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 970 s = ESC; 971 break; 972 case ESC_END: 973 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 974 s = END; 975 break; 976 } 977 if (!test_bit(SLF_ERROR, &sl->flags)) { 978 if (sl->rcount < sl->buffsize) { 979 sl->rbuff[sl->rcount++] = s; 980 return; 981 } 982 sl->dev->stats.rx_over_errors++; 983 set_bit(SLF_ERROR, &sl->flags); 984 } 985 } 986 987 988 #ifdef CONFIG_SLIP_MODE_SLIP6 989 /************************************************************************ 990 * 6 BIT SLIP ENCAPSULATION * 991 ************************************************************************/ 992 993 static int slip_esc6(unsigned char *s, unsigned char *d, int len) 994 { 995 unsigned char *ptr = d; 996 unsigned char c; 997 int i; 998 unsigned short v = 0; 999 short bits = 0; 1000 1001 /* 1002 * Send an initial END character to flush out any 1003 * data that may have accumulated in the receiver 1004 * due to line noise. 1005 */ 1006 1007 *ptr++ = 0x70; 1008 1009 /* 1010 * Encode the packet into printable ascii characters 1011 */ 1012 1013 for (i = 0; i < len; ++i) { 1014 v = (v << 8) | s[i]; 1015 bits += 8; 1016 while (bits >= 6) { 1017 bits -= 6; 1018 c = 0x30 + ((v >> bits) & 0x3F); 1019 *ptr++ = c; 1020 } 1021 } 1022 if (bits) { 1023 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1024 *ptr++ = c; 1025 } 1026 *ptr++ = 0x70; 1027 return ptr - d; 1028 } 1029 1030 static void slip_unesc6(struct slip *sl, unsigned char s) 1031 { 1032 unsigned char c; 1033 1034 if (s == 0x70) { 1035 #ifdef CONFIG_SLIP_SMART 1036 /* drop keeptest bit = VSV */ 1037 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1038 clear_bit(SLF_KEEPTEST, &sl->flags); 1039 #endif 1040 1041 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1042 (sl->rcount > 2)) 1043 sl_bump(sl); 1044 sl->rcount = 0; 1045 sl->xbits = 0; 1046 sl->xdata = 0; 1047 } else if (s >= 0x30 && s < 0x70) { 1048 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1049 sl->xbits += 6; 1050 if (sl->xbits >= 8) { 1051 sl->xbits -= 8; 1052 c = (unsigned char)(sl->xdata >> sl->xbits); 1053 if (!test_bit(SLF_ERROR, &sl->flags)) { 1054 if (sl->rcount < sl->buffsize) { 1055 sl->rbuff[sl->rcount++] = c; 1056 return; 1057 } 1058 sl->dev->stats.rx_over_errors++; 1059 set_bit(SLF_ERROR, &sl->flags); 1060 } 1061 } 1062 } 1063 } 1064 #endif /* CONFIG_SLIP_MODE_SLIP6 */ 1065 1066 /* Perform I/O control on an active SLIP channel. */ 1067 static int slip_ioctl(struct tty_struct *tty, struct file *file, 1068 unsigned int cmd, unsigned long arg) 1069 { 1070 struct slip *sl = tty->disc_data; 1071 unsigned int tmp; 1072 int __user *p = (int __user *)arg; 1073 1074 /* First make sure we're connected. */ 1075 if (!sl || sl->magic != SLIP_MAGIC) 1076 return -EINVAL; 1077 1078 switch (cmd) { 1079 case SIOCGIFNAME: 1080 tmp = strlen(sl->dev->name) + 1; 1081 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1082 return -EFAULT; 1083 return 0; 1084 1085 case SIOCGIFENCAP: 1086 if (put_user(sl->mode, p)) 1087 return -EFAULT; 1088 return 0; 1089 1090 case SIOCSIFENCAP: 1091 if (get_user(tmp, p)) 1092 return -EFAULT; 1093 #ifndef SL_INCLUDE_CSLIP 1094 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1095 return -EINVAL; 1096 #else 1097 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1098 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1099 /* return -EINVAL; */ 1100 tmp &= ~SL_MODE_ADAPTIVE; 1101 #endif 1102 #ifndef CONFIG_SLIP_MODE_SLIP6 1103 if (tmp & SL_MODE_SLIP6) 1104 return -EINVAL; 1105 #endif 1106 sl->mode = tmp; 1107 sl->dev->type = ARPHRD_SLIP + sl->mode; 1108 return 0; 1109 1110 case SIOCSIFHWADDR: 1111 return -EINVAL; 1112 1113 #ifdef CONFIG_SLIP_SMART 1114 /* VSV changes start here */ 1115 case SIOCSKEEPALIVE: 1116 if (get_user(tmp, p)) 1117 return -EFAULT; 1118 if (tmp > 255) /* max for unchar */ 1119 return -EINVAL; 1120 1121 spin_lock_bh(&sl->lock); 1122 if (!sl->tty) { 1123 spin_unlock_bh(&sl->lock); 1124 return -ENODEV; 1125 } 1126 sl->keepalive = (u8)tmp; 1127 if (sl->keepalive != 0) { 1128 mod_timer(&sl->keepalive_timer, 1129 jiffies + sl->keepalive * HZ); 1130 set_bit(SLF_KEEPTEST, &sl->flags); 1131 } else 1132 del_timer(&sl->keepalive_timer); 1133 spin_unlock_bh(&sl->lock); 1134 return 0; 1135 1136 case SIOCGKEEPALIVE: 1137 if (put_user(sl->keepalive, p)) 1138 return -EFAULT; 1139 return 0; 1140 1141 case SIOCSOUTFILL: 1142 if (get_user(tmp, p)) 1143 return -EFAULT; 1144 if (tmp > 255) /* max for unchar */ 1145 return -EINVAL; 1146 spin_lock_bh(&sl->lock); 1147 if (!sl->tty) { 1148 spin_unlock_bh(&sl->lock); 1149 return -ENODEV; 1150 } 1151 sl->outfill = (u8)tmp; 1152 if (sl->outfill != 0) { 1153 mod_timer(&sl->outfill_timer, 1154 jiffies + sl->outfill * HZ); 1155 set_bit(SLF_OUTWAIT, &sl->flags); 1156 } else 1157 del_timer(&sl->outfill_timer); 1158 spin_unlock_bh(&sl->lock); 1159 return 0; 1160 1161 case SIOCGOUTFILL: 1162 if (put_user(sl->outfill, p)) 1163 return -EFAULT; 1164 return 0; 1165 /* VSV changes end */ 1166 #endif 1167 default: 1168 return tty_mode_ioctl(tty, file, cmd, arg); 1169 } 1170 } 1171 1172 /* VSV changes start here */ 1173 #ifdef CONFIG_SLIP_SMART 1174 /* function do_ioctl called from net/core/dev.c 1175 to allow get/set outfill/keepalive parameter 1176 by ifconfig */ 1177 1178 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1179 { 1180 struct slip *sl = netdev_priv(dev); 1181 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1182 1183 if (sl == NULL) /* Allocation failed ?? */ 1184 return -ENODEV; 1185 1186 spin_lock_bh(&sl->lock); 1187 1188 if (!sl->tty) { 1189 spin_unlock_bh(&sl->lock); 1190 return -ENODEV; 1191 } 1192 1193 switch (cmd) { 1194 case SIOCSKEEPALIVE: 1195 /* max for unchar */ 1196 if ((unsigned)*p > 255) { 1197 spin_unlock_bh(&sl->lock); 1198 return -EINVAL; 1199 } 1200 sl->keepalive = (u8)*p; 1201 if (sl->keepalive != 0) { 1202 sl->keepalive_timer.expires = 1203 jiffies + sl->keepalive * HZ; 1204 mod_timer(&sl->keepalive_timer, 1205 jiffies + sl->keepalive * HZ); 1206 set_bit(SLF_KEEPTEST, &sl->flags); 1207 } else 1208 del_timer(&sl->keepalive_timer); 1209 break; 1210 1211 case SIOCGKEEPALIVE: 1212 *p = sl->keepalive; 1213 break; 1214 1215 case SIOCSOUTFILL: 1216 if ((unsigned)*p > 255) { /* max for unchar */ 1217 spin_unlock_bh(&sl->lock); 1218 return -EINVAL; 1219 } 1220 sl->outfill = (u8)*p; 1221 if (sl->outfill != 0) { 1222 mod_timer(&sl->outfill_timer, 1223 jiffies + sl->outfill * HZ); 1224 set_bit(SLF_OUTWAIT, &sl->flags); 1225 } else 1226 del_timer(&sl->outfill_timer); 1227 break; 1228 1229 case SIOCGOUTFILL: 1230 *p = sl->outfill; 1231 break; 1232 1233 case SIOCSLEASE: 1234 /* Resolve race condition, when ioctl'ing hanged up 1235 and opened by another process device. 1236 */ 1237 if (sl->tty != current->signal->tty && 1238 sl->pid != current->pid) { 1239 spin_unlock_bh(&sl->lock); 1240 return -EPERM; 1241 } 1242 sl->leased = 0; 1243 if (*p) 1244 sl->leased = 1; 1245 break; 1246 1247 case SIOCGLEASE: 1248 *p = sl->leased; 1249 } 1250 spin_unlock_bh(&sl->lock); 1251 return 0; 1252 } 1253 #endif 1254 /* VSV changes end */ 1255 1256 static struct tty_ldisc_ops sl_ldisc = { 1257 .owner = THIS_MODULE, 1258 .magic = TTY_LDISC_MAGIC, 1259 .name = "slip", 1260 .open = slip_open, 1261 .close = slip_close, 1262 .hangup = slip_hangup, 1263 .ioctl = slip_ioctl, 1264 .receive_buf = slip_receive_buf, 1265 .write_wakeup = slip_write_wakeup, 1266 }; 1267 1268 static int __init slip_init(void) 1269 { 1270 int status; 1271 1272 if (slip_maxdev < 4) 1273 slip_maxdev = 4; /* Sanity */ 1274 1275 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" 1276 #ifdef CONFIG_SLIP_MODE_SLIP6 1277 " (6 bit encapsulation enabled)" 1278 #endif 1279 ".\n", 1280 SLIP_VERSION, slip_maxdev); 1281 #if defined(SL_INCLUDE_CSLIP) 1282 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); 1283 #endif 1284 #ifdef CONFIG_SLIP_SMART 1285 printk(KERN_INFO "SLIP linefill/keepalive option.\n"); 1286 #endif 1287 1288 slip_devs = kcalloc(slip_maxdev, sizeof(struct net_device *), 1289 GFP_KERNEL); 1290 if (!slip_devs) 1291 return -ENOMEM; 1292 1293 /* Fill in our line protocol discipline, and register it */ 1294 status = tty_register_ldisc(N_SLIP, &sl_ldisc); 1295 if (status != 0) { 1296 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); 1297 kfree(slip_devs); 1298 } 1299 return status; 1300 } 1301 1302 static void __exit slip_exit(void) 1303 { 1304 int i; 1305 struct net_device *dev; 1306 struct slip *sl; 1307 unsigned long timeout = jiffies + HZ; 1308 int busy = 0; 1309 1310 if (slip_devs == NULL) 1311 return; 1312 1313 /* First of all: check for active disciplines and hangup them. 1314 */ 1315 do { 1316 if (busy) 1317 msleep_interruptible(100); 1318 1319 busy = 0; 1320 for (i = 0; i < slip_maxdev; i++) { 1321 dev = slip_devs[i]; 1322 if (!dev) 1323 continue; 1324 sl = netdev_priv(dev); 1325 spin_lock_bh(&sl->lock); 1326 if (sl->tty) { 1327 busy++; 1328 tty_hangup(sl->tty); 1329 } 1330 spin_unlock_bh(&sl->lock); 1331 } 1332 } while (busy && time_before(jiffies, timeout)); 1333 1334 /* FIXME: hangup is async so we should wait when doing this second 1335 phase */ 1336 1337 for (i = 0; i < slip_maxdev; i++) { 1338 dev = slip_devs[i]; 1339 if (!dev) 1340 continue; 1341 slip_devs[i] = NULL; 1342 1343 sl = netdev_priv(dev); 1344 if (sl->tty) { 1345 printk(KERN_ERR "%s: tty discipline still running\n", 1346 dev->name); 1347 } 1348 1349 unregister_netdev(dev); 1350 } 1351 1352 kfree(slip_devs); 1353 slip_devs = NULL; 1354 1355 i = tty_unregister_ldisc(N_SLIP); 1356 if (i != 0) 1357 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1358 } 1359 1360 module_init(slip_init); 1361 module_exit(slip_exit); 1362 1363 #ifdef CONFIG_SLIP_SMART 1364 /* 1365 * This is start of the code for multislip style line checking 1366 * added by Stanislav Voronyi. All changes before marked VSV 1367 */ 1368 1369 static void sl_outfill(struct timer_list *t) 1370 { 1371 struct slip *sl = from_timer(sl, t, outfill_timer); 1372 1373 spin_lock(&sl->lock); 1374 1375 if (sl->tty == NULL) 1376 goto out; 1377 1378 if (sl->outfill) { 1379 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1380 /* no packets were transmitted, do outfill */ 1381 #ifdef CONFIG_SLIP_MODE_SLIP6 1382 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1383 #else 1384 unsigned char s = END; 1385 #endif 1386 /* put END into tty queue. Is it right ??? */ 1387 if (!netif_queue_stopped(sl->dev)) { 1388 /* if device busy no outfill */ 1389 sl->tty->ops->write(sl->tty, &s, 1); 1390 } 1391 } else 1392 set_bit(SLF_OUTWAIT, &sl->flags); 1393 1394 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1395 } 1396 out: 1397 spin_unlock(&sl->lock); 1398 } 1399 1400 static void sl_keepalive(struct timer_list *t) 1401 { 1402 struct slip *sl = from_timer(sl, t, keepalive_timer); 1403 1404 spin_lock(&sl->lock); 1405 1406 if (sl->tty == NULL) 1407 goto out; 1408 1409 if (sl->keepalive) { 1410 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1411 /* keepalive still high :(, we must hangup */ 1412 if (sl->outfill) 1413 /* outfill timer must be deleted too */ 1414 (void)del_timer(&sl->outfill_timer); 1415 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1416 /* this must hangup tty & close slip */ 1417 tty_hangup(sl->tty); 1418 /* I think we need not something else */ 1419 goto out; 1420 } else 1421 set_bit(SLF_KEEPTEST, &sl->flags); 1422 1423 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1424 } 1425 out: 1426 spin_unlock(&sl->lock); 1427 } 1428 1429 #endif 1430 MODULE_LICENSE("GPL"); 1431 MODULE_ALIAS_LDISC(N_SLIP); 1432