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