1 /* 2 * slip.c This module implements the SLIP protocol for kernel-based 3 * devices like TTY. It interfaces between a raw TTY, and the 4 * kernel's INET protocol layers. 5 * 6 * Version: @(#)slip.c 0.8.3 12/24/94 7 * 8 * Authors: Laurence Culhane, <loz@holmes.demon.co.uk> 9 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> 10 * 11 * Fixes: 12 * Alan Cox : Sanity checks and avoid tx overruns. 13 * Has a new sl->mtu field. 14 * Alan Cox : Found cause of overrun. ifconfig sl0 15 * mtu upwards. Driver now spots this 16 * and grows/shrinks its buffers(hack!). 17 * Memory leak if you run out of memory 18 * setting up a slip driver fixed. 19 * Matt Dillon : Printable slip (borrowed from NET2E) 20 * Pauline Middelink : Slip driver fixes. 21 * Alan Cox : Honours the old SL_COMPRESSED flag 22 * Alan Cox : KISS AX.25 and AXUI IP support 23 * Michael Riepe : Automatic CSLIP recognition added 24 * Charles Hedrick : CSLIP header length problem fix. 25 * Alan Cox : Corrected non-IP cases of the above. 26 * Alan Cox : Now uses hardware type as per FvK. 27 * Alan Cox : Default to 192.168.0.0 (RFC 1597) 28 * A.N.Kuznetsov : dev_tint() recursion fix. 29 * Dmitry Gorodchanin : SLIP memory leaks 30 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver 31 * buffering from 4096 to 256 bytes. 32 * Improving SLIP response time. 33 * CONFIG_SLIP_MODE_SLIP6. 34 * ifconfig sl? up & down now works 35 * correctly. 36 * Modularization. 37 * Alan Cox : Oops - fix AX.25 buffer lengths 38 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP 39 * statistics. Include CSLIP code only 40 * if it really needed. 41 * Alan Cox : Free slhc buffers in the right place. 42 * Alan Cox : Allow for digipeated IP over AX.25 43 * Matti Aarnio : Dynamic SLIP devices, with ideas taken 44 * from Jim Freeman's <jfree@caldera.com> 45 * dynamic PPP devices. We do NOT kfree() 46 * device entries, just reg./unreg. them 47 * as they are needed. We kfree() them 48 * at module cleanup. 49 * With MODULE-loading ``insmod'', user 50 * can issue parameter: slip_maxdev=1024 51 * (Or how much he/she wants.. Default 52 * is 256) 53 * Stanislav Voronyi : Slip line checking, with ideas taken 54 * from multislip BSDI driver which was 55 * written by Igor Chechik, RELCOM Corp. 56 * Only algorithms have been ported to 57 * Linux SLIP driver. 58 * Vitaly E. Lavrov : Sane behaviour on tty hangup. 59 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice 60 * modules. 61 */ 62 63 #define SL_CHECK_TRANSMIT 64 #include <linux/module.h> 65 #include <linux/moduleparam.h> 66 67 #include <asm/uaccess.h> 68 #include <linux/bitops.h> 69 #include <linux/sched.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/compat.h> 83 #include <linux/delay.h> 84 #include <linux/init.h> 85 #include <linux/slab.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(unsigned long sls); 109 static void sl_outfill(unsigned long sls); 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 (slcomp == NULL) 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 memcpy(skb_put(skb, count), 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 sl->dev->trans_start = jiffies; 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 /* 420 * Called by the driver when there's room for more data. If we have 421 * more packets to send, we send them here. 422 */ 423 static void slip_write_wakeup(struct tty_struct *tty) 424 { 425 int actual; 426 struct slip *sl = tty->disc_data; 427 428 /* First make sure we're connected. */ 429 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 430 return; 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, &tty->flags); 437 sl_unlock(sl); 438 return; 439 } 440 441 actual = tty->ops->write(tty, sl->xhead, sl->xleft); 442 sl->xleft -= actual; 443 sl->xhead += actual; 444 } 445 446 static void sl_tx_timeout(struct net_device *dev) 447 { 448 struct slip *sl = netdev_priv(dev); 449 450 spin_lock(&sl->lock); 451 452 if (netif_queue_stopped(dev)) { 453 if (!netif_running(dev)) 454 goto out; 455 456 /* May be we must check transmitter timeout here ? 457 * 14 Oct 1994 Dmitry Gorodchanin. 458 */ 459 #ifdef SL_CHECK_TRANSMIT 460 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) { 461 /* 20 sec timeout not reached */ 462 goto out; 463 } 464 printk(KERN_WARNING "%s: transmit timed out, %s?\n", 465 dev->name, 466 (tty_chars_in_buffer(sl->tty) || sl->xleft) ? 467 "bad line quality" : "driver error"); 468 sl->xleft = 0; 469 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 470 sl_unlock(sl); 471 #endif 472 } 473 out: 474 spin_unlock(&sl->lock); 475 } 476 477 478 /* Encapsulate an IP datagram and kick it into a TTY queue. */ 479 static netdev_tx_t 480 sl_xmit(struct sk_buff *skb, struct net_device *dev) 481 { 482 struct slip *sl = netdev_priv(dev); 483 484 spin_lock(&sl->lock); 485 if (!netif_running(dev)) { 486 spin_unlock(&sl->lock); 487 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name); 488 dev_kfree_skb(skb); 489 return NETDEV_TX_OK; 490 } 491 if (sl->tty == NULL) { 492 spin_unlock(&sl->lock); 493 dev_kfree_skb(skb); 494 return NETDEV_TX_OK; 495 } 496 497 sl_lock(sl); 498 dev->stats.tx_bytes += skb->len; 499 sl_encaps(sl, skb->data, skb->len); 500 spin_unlock(&sl->lock); 501 502 dev_kfree_skb(skb); 503 return NETDEV_TX_OK; 504 } 505 506 507 /****************************************** 508 * Routines looking at netdevice side. 509 ******************************************/ 510 511 /* Netdevice UP -> DOWN routine */ 512 513 static int 514 sl_close(struct net_device *dev) 515 { 516 struct slip *sl = netdev_priv(dev); 517 518 spin_lock_bh(&sl->lock); 519 if (sl->tty) 520 /* TTY discipline is running. */ 521 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); 522 netif_stop_queue(dev); 523 sl->rcount = 0; 524 sl->xleft = 0; 525 spin_unlock_bh(&sl->lock); 526 527 return 0; 528 } 529 530 /* Netdevice DOWN -> UP routine */ 531 532 static int sl_open(struct net_device *dev) 533 { 534 struct slip *sl = netdev_priv(dev); 535 536 if (sl->tty == NULL) 537 return -ENODEV; 538 539 sl->flags &= (1 << SLF_INUSE); 540 netif_start_queue(dev); 541 return 0; 542 } 543 544 /* Netdevice change MTU request */ 545 546 static int sl_change_mtu(struct net_device *dev, int new_mtu) 547 { 548 struct slip *sl = netdev_priv(dev); 549 550 if (new_mtu < 68 || new_mtu > 65534) 551 return -EINVAL; 552 553 if (new_mtu != dev->mtu) 554 return sl_realloc_bufs(sl, new_mtu); 555 return 0; 556 } 557 558 /* Netdevice get statistics request */ 559 560 static struct rtnl_link_stats64 * 561 sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) 562 { 563 struct net_device_stats *devstats = &dev->stats; 564 #ifdef SL_INCLUDE_CSLIP 565 struct slip *sl = netdev_priv(dev); 566 struct slcompress *comp = sl->slcomp; 567 #endif 568 stats->rx_packets = devstats->rx_packets; 569 stats->tx_packets = devstats->tx_packets; 570 stats->rx_bytes = devstats->rx_bytes; 571 stats->tx_bytes = devstats->tx_bytes; 572 stats->rx_dropped = devstats->rx_dropped; 573 stats->tx_dropped = devstats->tx_dropped; 574 stats->tx_errors = devstats->tx_errors; 575 stats->rx_errors = devstats->rx_errors; 576 stats->rx_over_errors = devstats->rx_over_errors; 577 578 #ifdef SL_INCLUDE_CSLIP 579 if (comp) { 580 /* Generic compressed statistics */ 581 stats->rx_compressed = comp->sls_i_compressed; 582 stats->tx_compressed = comp->sls_o_compressed; 583 584 /* Are we really still needs this? */ 585 stats->rx_fifo_errors += comp->sls_i_compressed; 586 stats->rx_dropped += comp->sls_i_tossed; 587 stats->tx_fifo_errors += comp->sls_o_compressed; 588 stats->collisions += comp->sls_o_misses; 589 } 590 #endif 591 return stats; 592 } 593 594 /* Netdevice register callback */ 595 596 static int sl_init(struct net_device *dev) 597 { 598 struct slip *sl = netdev_priv(dev); 599 600 /* 601 * Finish setting up the DEVICE info. 602 */ 603 604 dev->mtu = sl->mtu; 605 dev->type = ARPHRD_SLIP + sl->mode; 606 #ifdef SL_CHECK_TRANSMIT 607 dev->watchdog_timeo = 20*HZ; 608 #endif 609 return 0; 610 } 611 612 613 static void sl_uninit(struct net_device *dev) 614 { 615 struct slip *sl = netdev_priv(dev); 616 617 sl_free_bufs(sl); 618 } 619 620 /* Hook the destructor so we can free slip devices at the right point in time */ 621 static void sl_free_netdev(struct net_device *dev) 622 { 623 int i = dev->base_addr; 624 free_netdev(dev); 625 slip_devs[i] = NULL; 626 } 627 628 static const struct net_device_ops sl_netdev_ops = { 629 .ndo_init = sl_init, 630 .ndo_uninit = sl_uninit, 631 .ndo_open = sl_open, 632 .ndo_stop = sl_close, 633 .ndo_start_xmit = sl_xmit, 634 .ndo_get_stats64 = sl_get_stats64, 635 .ndo_change_mtu = sl_change_mtu, 636 .ndo_tx_timeout = sl_tx_timeout, 637 #ifdef CONFIG_SLIP_SMART 638 .ndo_do_ioctl = sl_ioctl, 639 #endif 640 }; 641 642 643 static void sl_setup(struct net_device *dev) 644 { 645 dev->netdev_ops = &sl_netdev_ops; 646 dev->destructor = sl_free_netdev; 647 648 dev->hard_header_len = 0; 649 dev->addr_len = 0; 650 dev->tx_queue_len = 10; 651 652 /* New-style flags. */ 653 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; 654 } 655 656 /****************************************** 657 Routines looking at TTY side. 658 ******************************************/ 659 660 661 /* 662 * Handle the 'receiver data ready' interrupt. 663 * This function is called by the 'tty_io' module in the kernel when 664 * a block of SLIP data has been received, which can now be decapsulated 665 * and sent on to some IP layer for further processing. This will not 666 * be re-entered while running but other ldisc functions may be called 667 * in parallel 668 */ 669 670 static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, 671 char *fp, int count) 672 { 673 struct slip *sl = tty->disc_data; 674 675 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) 676 return; 677 678 /* Read the characters out of the buffer */ 679 while (count--) { 680 if (fp && *fp++) { 681 if (!test_and_set_bit(SLF_ERROR, &sl->flags)) 682 sl->dev->stats.rx_errors++; 683 cp++; 684 continue; 685 } 686 #ifdef CONFIG_SLIP_MODE_SLIP6 687 if (sl->mode & SL_MODE_SLIP6) 688 slip_unesc6(sl, *cp++); 689 else 690 #endif 691 slip_unesc(sl, *cp++); 692 } 693 } 694 695 /************************************ 696 * slip_open helper routines. 697 ************************************/ 698 699 /* Collect hanged up channels */ 700 static void sl_sync(void) 701 { 702 int i; 703 struct net_device *dev; 704 struct slip *sl; 705 706 for (i = 0; i < slip_maxdev; i++) { 707 dev = slip_devs[i]; 708 if (dev == NULL) 709 break; 710 711 sl = netdev_priv(dev); 712 if (sl->tty || sl->leased) 713 continue; 714 if (dev->flags & IFF_UP) 715 dev_close(dev); 716 } 717 } 718 719 720 /* Find a free SLIP channel, and link in this `tty' line. */ 721 static struct slip *sl_alloc(dev_t line) 722 { 723 int i; 724 char name[IFNAMSIZ]; 725 struct net_device *dev = NULL; 726 struct slip *sl; 727 728 for (i = 0; i < slip_maxdev; i++) { 729 dev = slip_devs[i]; 730 if (dev == NULL) 731 break; 732 } 733 /* Sorry, too many, all slots in use */ 734 if (i >= slip_maxdev) 735 return NULL; 736 737 sprintf(name, "sl%d", i); 738 dev = alloc_netdev(sizeof(*sl), name, sl_setup); 739 if (!dev) 740 return NULL; 741 742 dev->base_addr = i; 743 sl = netdev_priv(dev); 744 745 /* Initialize channel control data */ 746 sl->magic = SLIP_MAGIC; 747 sl->dev = dev; 748 spin_lock_init(&sl->lock); 749 sl->mode = SL_MODE_DEFAULT; 750 #ifdef CONFIG_SLIP_SMART 751 /* initialize timer_list struct */ 752 init_timer(&sl->keepalive_timer); 753 sl->keepalive_timer.data = (unsigned long)sl; 754 sl->keepalive_timer.function = sl_keepalive; 755 init_timer(&sl->outfill_timer); 756 sl->outfill_timer.data = (unsigned long)sl; 757 sl->outfill_timer.function = sl_outfill; 758 #endif 759 slip_devs[i] = dev; 760 return sl; 761 } 762 763 /* 764 * Open the high-level part of the SLIP channel. 765 * This function is called by the TTY module when the 766 * SLIP line discipline is called for. Because we are 767 * sure the tty line exists, we only have to link it to 768 * a free SLIP channel... 769 * 770 * Called in process context serialized from other ldisc calls. 771 */ 772 773 static int slip_open(struct tty_struct *tty) 774 { 775 struct slip *sl; 776 int err; 777 778 if (!capable(CAP_NET_ADMIN)) 779 return -EPERM; 780 781 if (tty->ops->write == NULL) 782 return -EOPNOTSUPP; 783 784 /* RTnetlink lock is misused here to serialize concurrent 785 opens of slip channels. There are better ways, but it is 786 the simplest one. 787 */ 788 rtnl_lock(); 789 790 /* Collect hanged up channels. */ 791 sl_sync(); 792 793 sl = tty->disc_data; 794 795 err = -EEXIST; 796 /* First make sure we're not already connected. */ 797 if (sl && sl->magic == SLIP_MAGIC) 798 goto err_exit; 799 800 /* OK. Find a free SLIP channel to use. */ 801 err = -ENFILE; 802 sl = sl_alloc(tty_devnum(tty)); 803 if (sl == NULL) 804 goto err_exit; 805 806 sl->tty = tty; 807 tty->disc_data = sl; 808 sl->pid = current->pid; 809 810 if (!test_bit(SLF_INUSE, &sl->flags)) { 811 /* Perform the low-level SLIP initialization. */ 812 err = sl_alloc_bufs(sl, SL_MTU); 813 if (err) 814 goto err_free_chan; 815 816 set_bit(SLF_INUSE, &sl->flags); 817 818 err = register_netdevice(sl->dev); 819 if (err) 820 goto err_free_bufs; 821 } 822 823 #ifdef CONFIG_SLIP_SMART 824 if (sl->keepalive) { 825 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; 826 add_timer(&sl->keepalive_timer); 827 } 828 if (sl->outfill) { 829 sl->outfill_timer.expires = jiffies + sl->outfill * HZ; 830 add_timer(&sl->outfill_timer); 831 } 832 #endif 833 834 /* Done. We have linked the TTY line to a channel. */ 835 rtnl_unlock(); 836 tty->receive_room = 65536; /* We don't flow control */ 837 838 /* TTY layer expects 0 on success */ 839 return 0; 840 841 err_free_bufs: 842 sl_free_bufs(sl); 843 844 err_free_chan: 845 sl->tty = NULL; 846 tty->disc_data = NULL; 847 clear_bit(SLF_INUSE, &sl->flags); 848 849 err_exit: 850 rtnl_unlock(); 851 852 /* Count references from TTY module */ 853 return err; 854 } 855 856 /* 857 * Close down a SLIP channel. 858 * This means flushing out any pending queues, and then returning. This 859 * call is serialized against other ldisc functions. 860 * 861 * We also use this method fo a hangup event 862 */ 863 864 static void slip_close(struct tty_struct *tty) 865 { 866 struct slip *sl = tty->disc_data; 867 868 /* First make sure we're connected. */ 869 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) 870 return; 871 872 tty->disc_data = NULL; 873 sl->tty = NULL; 874 875 /* VSV = very important to remove timers */ 876 #ifdef CONFIG_SLIP_SMART 877 del_timer_sync(&sl->keepalive_timer); 878 del_timer_sync(&sl->outfill_timer); 879 #endif 880 /* Flush network side */ 881 unregister_netdev(sl->dev); 882 /* This will complete via sl_free_netdev */ 883 } 884 885 static int slip_hangup(struct tty_struct *tty) 886 { 887 slip_close(tty); 888 return 0; 889 } 890 /************************************************************************ 891 * STANDARD SLIP ENCAPSULATION * 892 ************************************************************************/ 893 894 static int slip_esc(unsigned char *s, unsigned char *d, int len) 895 { 896 unsigned char *ptr = d; 897 unsigned char c; 898 899 /* 900 * Send an initial END character to flush out any 901 * data that may have accumulated in the receiver 902 * due to line noise. 903 */ 904 905 *ptr++ = END; 906 907 /* 908 * For each byte in the packet, send the appropriate 909 * character sequence, according to the SLIP protocol. 910 */ 911 912 while (len-- > 0) { 913 switch (c = *s++) { 914 case END: 915 *ptr++ = ESC; 916 *ptr++ = ESC_END; 917 break; 918 case ESC: 919 *ptr++ = ESC; 920 *ptr++ = ESC_ESC; 921 break; 922 default: 923 *ptr++ = c; 924 break; 925 } 926 } 927 *ptr++ = END; 928 return ptr - d; 929 } 930 931 static void slip_unesc(struct slip *sl, unsigned char s) 932 { 933 934 switch (s) { 935 case END: 936 #ifdef CONFIG_SLIP_SMART 937 /* drop keeptest bit = VSV */ 938 if (test_bit(SLF_KEEPTEST, &sl->flags)) 939 clear_bit(SLF_KEEPTEST, &sl->flags); 940 #endif 941 942 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 943 (sl->rcount > 2)) 944 sl_bump(sl); 945 clear_bit(SLF_ESCAPE, &sl->flags); 946 sl->rcount = 0; 947 return; 948 949 case ESC: 950 set_bit(SLF_ESCAPE, &sl->flags); 951 return; 952 case ESC_ESC: 953 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 954 s = ESC; 955 break; 956 case ESC_END: 957 if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) 958 s = END; 959 break; 960 } 961 if (!test_bit(SLF_ERROR, &sl->flags)) { 962 if (sl->rcount < sl->buffsize) { 963 sl->rbuff[sl->rcount++] = s; 964 return; 965 } 966 sl->dev->stats.rx_over_errors++; 967 set_bit(SLF_ERROR, &sl->flags); 968 } 969 } 970 971 972 #ifdef CONFIG_SLIP_MODE_SLIP6 973 /************************************************************************ 974 * 6 BIT SLIP ENCAPSULATION * 975 ************************************************************************/ 976 977 static int slip_esc6(unsigned char *s, unsigned char *d, int len) 978 { 979 unsigned char *ptr = d; 980 unsigned char c; 981 int i; 982 unsigned short v = 0; 983 short bits = 0; 984 985 /* 986 * Send an initial END character to flush out any 987 * data that may have accumulated in the receiver 988 * due to line noise. 989 */ 990 991 *ptr++ = 0x70; 992 993 /* 994 * Encode the packet into printable ascii characters 995 */ 996 997 for (i = 0; i < len; ++i) { 998 v = (v << 8) | s[i]; 999 bits += 8; 1000 while (bits >= 6) { 1001 bits -= 6; 1002 c = 0x30 + ((v >> bits) & 0x3F); 1003 *ptr++ = c; 1004 } 1005 } 1006 if (bits) { 1007 c = 0x30 + ((v << (6 - bits)) & 0x3F); 1008 *ptr++ = c; 1009 } 1010 *ptr++ = 0x70; 1011 return ptr - d; 1012 } 1013 1014 static void slip_unesc6(struct slip *sl, unsigned char s) 1015 { 1016 unsigned char c; 1017 1018 if (s == 0x70) { 1019 #ifdef CONFIG_SLIP_SMART 1020 /* drop keeptest bit = VSV */ 1021 if (test_bit(SLF_KEEPTEST, &sl->flags)) 1022 clear_bit(SLF_KEEPTEST, &sl->flags); 1023 #endif 1024 1025 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && 1026 (sl->rcount > 2)) 1027 sl_bump(sl); 1028 sl->rcount = 0; 1029 sl->xbits = 0; 1030 sl->xdata = 0; 1031 } else if (s >= 0x30 && s < 0x70) { 1032 sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); 1033 sl->xbits += 6; 1034 if (sl->xbits >= 8) { 1035 sl->xbits -= 8; 1036 c = (unsigned char)(sl->xdata >> sl->xbits); 1037 if (!test_bit(SLF_ERROR, &sl->flags)) { 1038 if (sl->rcount < sl->buffsize) { 1039 sl->rbuff[sl->rcount++] = c; 1040 return; 1041 } 1042 sl->dev->stats.rx_over_errors++; 1043 set_bit(SLF_ERROR, &sl->flags); 1044 } 1045 } 1046 } 1047 } 1048 #endif /* CONFIG_SLIP_MODE_SLIP6 */ 1049 1050 /* Perform I/O control on an active SLIP channel. */ 1051 static int slip_ioctl(struct tty_struct *tty, struct file *file, 1052 unsigned int cmd, unsigned long arg) 1053 { 1054 struct slip *sl = tty->disc_data; 1055 unsigned int tmp; 1056 int __user *p = (int __user *)arg; 1057 1058 /* First make sure we're connected. */ 1059 if (!sl || sl->magic != SLIP_MAGIC) 1060 return -EINVAL; 1061 1062 switch (cmd) { 1063 case SIOCGIFNAME: 1064 tmp = strlen(sl->dev->name) + 1; 1065 if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) 1066 return -EFAULT; 1067 return 0; 1068 1069 case SIOCGIFENCAP: 1070 if (put_user(sl->mode, p)) 1071 return -EFAULT; 1072 return 0; 1073 1074 case SIOCSIFENCAP: 1075 if (get_user(tmp, p)) 1076 return -EFAULT; 1077 #ifndef SL_INCLUDE_CSLIP 1078 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) 1079 return -EINVAL; 1080 #else 1081 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == 1082 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) 1083 /* return -EINVAL; */ 1084 tmp &= ~SL_MODE_ADAPTIVE; 1085 #endif 1086 #ifndef CONFIG_SLIP_MODE_SLIP6 1087 if (tmp & SL_MODE_SLIP6) 1088 return -EINVAL; 1089 #endif 1090 sl->mode = tmp; 1091 sl->dev->type = ARPHRD_SLIP + sl->mode; 1092 return 0; 1093 1094 case SIOCSIFHWADDR: 1095 return -EINVAL; 1096 1097 #ifdef CONFIG_SLIP_SMART 1098 /* VSV changes start here */ 1099 case SIOCSKEEPALIVE: 1100 if (get_user(tmp, p)) 1101 return -EFAULT; 1102 if (tmp > 255) /* max for unchar */ 1103 return -EINVAL; 1104 1105 spin_lock_bh(&sl->lock); 1106 if (!sl->tty) { 1107 spin_unlock_bh(&sl->lock); 1108 return -ENODEV; 1109 } 1110 sl->keepalive = (u8)tmp; 1111 if (sl->keepalive != 0) { 1112 mod_timer(&sl->keepalive_timer, 1113 jiffies + sl->keepalive * HZ); 1114 set_bit(SLF_KEEPTEST, &sl->flags); 1115 } else 1116 del_timer(&sl->keepalive_timer); 1117 spin_unlock_bh(&sl->lock); 1118 return 0; 1119 1120 case SIOCGKEEPALIVE: 1121 if (put_user(sl->keepalive, p)) 1122 return -EFAULT; 1123 return 0; 1124 1125 case SIOCSOUTFILL: 1126 if (get_user(tmp, p)) 1127 return -EFAULT; 1128 if (tmp > 255) /* max for unchar */ 1129 return -EINVAL; 1130 spin_lock_bh(&sl->lock); 1131 if (!sl->tty) { 1132 spin_unlock_bh(&sl->lock); 1133 return -ENODEV; 1134 } 1135 sl->outfill = (u8)tmp; 1136 if (sl->outfill != 0) { 1137 mod_timer(&sl->outfill_timer, 1138 jiffies + sl->outfill * HZ); 1139 set_bit(SLF_OUTWAIT, &sl->flags); 1140 } else 1141 del_timer(&sl->outfill_timer); 1142 spin_unlock_bh(&sl->lock); 1143 return 0; 1144 1145 case SIOCGOUTFILL: 1146 if (put_user(sl->outfill, p)) 1147 return -EFAULT; 1148 return 0; 1149 /* VSV changes end */ 1150 #endif 1151 default: 1152 return tty_mode_ioctl(tty, file, cmd, arg); 1153 } 1154 } 1155 1156 #ifdef CONFIG_COMPAT 1157 static long slip_compat_ioctl(struct tty_struct *tty, struct file *file, 1158 unsigned int cmd, unsigned long arg) 1159 { 1160 switch (cmd) { 1161 case SIOCGIFNAME: 1162 case SIOCGIFENCAP: 1163 case SIOCSIFENCAP: 1164 case SIOCSIFHWADDR: 1165 case SIOCSKEEPALIVE: 1166 case SIOCGKEEPALIVE: 1167 case SIOCSOUTFILL: 1168 case SIOCGOUTFILL: 1169 return slip_ioctl(tty, file, cmd, 1170 (unsigned long)compat_ptr(arg)); 1171 } 1172 1173 return -ENOIOCTLCMD; 1174 } 1175 #endif 1176 1177 /* VSV changes start here */ 1178 #ifdef CONFIG_SLIP_SMART 1179 /* function do_ioctl called from net/core/dev.c 1180 to allow get/set outfill/keepalive parameter 1181 by ifconfig */ 1182 1183 static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) 1184 { 1185 struct slip *sl = netdev_priv(dev); 1186 unsigned long *p = (unsigned long *)&rq->ifr_ifru; 1187 1188 if (sl == NULL) /* Allocation failed ?? */ 1189 return -ENODEV; 1190 1191 spin_lock_bh(&sl->lock); 1192 1193 if (!sl->tty) { 1194 spin_unlock_bh(&sl->lock); 1195 return -ENODEV; 1196 } 1197 1198 switch (cmd) { 1199 case SIOCSKEEPALIVE: 1200 /* max for unchar */ 1201 if ((unsigned)*p > 255) { 1202 spin_unlock_bh(&sl->lock); 1203 return -EINVAL; 1204 } 1205 sl->keepalive = (u8)*p; 1206 if (sl->keepalive != 0) { 1207 sl->keepalive_timer.expires = 1208 jiffies + sl->keepalive * HZ; 1209 mod_timer(&sl->keepalive_timer, 1210 jiffies + sl->keepalive * HZ); 1211 set_bit(SLF_KEEPTEST, &sl->flags); 1212 } else 1213 del_timer(&sl->keepalive_timer); 1214 break; 1215 1216 case SIOCGKEEPALIVE: 1217 *p = sl->keepalive; 1218 break; 1219 1220 case SIOCSOUTFILL: 1221 if ((unsigned)*p > 255) { /* max for unchar */ 1222 spin_unlock_bh(&sl->lock); 1223 return -EINVAL; 1224 } 1225 sl->outfill = (u8)*p; 1226 if (sl->outfill != 0) { 1227 mod_timer(&sl->outfill_timer, 1228 jiffies + sl->outfill * HZ); 1229 set_bit(SLF_OUTWAIT, &sl->flags); 1230 } else 1231 del_timer(&sl->outfill_timer); 1232 break; 1233 1234 case SIOCGOUTFILL: 1235 *p = sl->outfill; 1236 break; 1237 1238 case SIOCSLEASE: 1239 /* Resolve race condition, when ioctl'ing hanged up 1240 and opened by another process device. 1241 */ 1242 if (sl->tty != current->signal->tty && 1243 sl->pid != current->pid) { 1244 spin_unlock_bh(&sl->lock); 1245 return -EPERM; 1246 } 1247 sl->leased = 0; 1248 if (*p) 1249 sl->leased = 1; 1250 break; 1251 1252 case SIOCGLEASE: 1253 *p = sl->leased; 1254 } 1255 spin_unlock_bh(&sl->lock); 1256 return 0; 1257 } 1258 #endif 1259 /* VSV changes end */ 1260 1261 static struct tty_ldisc_ops sl_ldisc = { 1262 .owner = THIS_MODULE, 1263 .magic = TTY_LDISC_MAGIC, 1264 .name = "slip", 1265 .open = slip_open, 1266 .close = slip_close, 1267 .hangup = slip_hangup, 1268 .ioctl = slip_ioctl, 1269 #ifdef CONFIG_COMPAT 1270 .compat_ioctl = slip_compat_ioctl, 1271 #endif 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 = kzalloc(sizeof(struct net_device *)*slip_maxdev, 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 /* Intentionally leak the control block. */ 1356 dev->destructor = NULL; 1357 } 1358 1359 unregister_netdev(dev); 1360 } 1361 1362 kfree(slip_devs); 1363 slip_devs = NULL; 1364 1365 i = tty_unregister_ldisc(N_SLIP); 1366 if (i != 0) 1367 printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); 1368 } 1369 1370 module_init(slip_init); 1371 module_exit(slip_exit); 1372 1373 #ifdef CONFIG_SLIP_SMART 1374 /* 1375 * This is start of the code for multislip style line checking 1376 * added by Stanislav Voronyi. All changes before marked VSV 1377 */ 1378 1379 static void sl_outfill(unsigned long sls) 1380 { 1381 struct slip *sl = (struct slip *)sls; 1382 1383 spin_lock(&sl->lock); 1384 1385 if (sl->tty == NULL) 1386 goto out; 1387 1388 if (sl->outfill) { 1389 if (test_bit(SLF_OUTWAIT, &sl->flags)) { 1390 /* no packets were transmitted, do outfill */ 1391 #ifdef CONFIG_SLIP_MODE_SLIP6 1392 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; 1393 #else 1394 unsigned char s = END; 1395 #endif 1396 /* put END into tty queue. Is it right ??? */ 1397 if (!netif_queue_stopped(sl->dev)) { 1398 /* if device busy no outfill */ 1399 sl->tty->ops->write(sl->tty, &s, 1); 1400 } 1401 } else 1402 set_bit(SLF_OUTWAIT, &sl->flags); 1403 1404 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); 1405 } 1406 out: 1407 spin_unlock(&sl->lock); 1408 } 1409 1410 static void sl_keepalive(unsigned long sls) 1411 { 1412 struct slip *sl = (struct slip *)sls; 1413 1414 spin_lock(&sl->lock); 1415 1416 if (sl->tty == NULL) 1417 goto out; 1418 1419 if (sl->keepalive) { 1420 if (test_bit(SLF_KEEPTEST, &sl->flags)) { 1421 /* keepalive still high :(, we must hangup */ 1422 if (sl->outfill) 1423 /* outfill timer must be deleted too */ 1424 (void)del_timer(&sl->outfill_timer); 1425 printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); 1426 /* this must hangup tty & close slip */ 1427 tty_hangup(sl->tty); 1428 /* I think we need not something else */ 1429 goto out; 1430 } else 1431 set_bit(SLF_KEEPTEST, &sl->flags); 1432 1433 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); 1434 } 1435 out: 1436 spin_unlock(&sl->lock); 1437 } 1438 1439 #endif 1440 MODULE_LICENSE("GPL"); 1441 MODULE_ALIAS_LDISC(N_SLIP); 1442