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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * slip.c This module implements the SLIP protocol for kernel-based4 * devices like TTY. It interfaces between a raw TTY, and the5 * kernel's INET protocol layers.6 *7 * Version: @(#)slip.c 0.8.3 12/24/948 *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 sl016 * mtu upwards. Driver now spots this17 * and grows/shrinks its buffers(hack!).18 * Memory leak if you run out of memory19 * 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 flag23 * Alan Cox : KISS AX.25 and AXUI IP support24 * Michael Riepe : Automatic CSLIP recognition added25 * 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 leaks31 * Dmitry Gorodchanin : Code cleanup. Reduce tty driver32 * buffering from 4096 to 256 bytes.33 * Improving SLIP response time.34 * CONFIG_SLIP_MODE_SLIP6.35 * ifconfig sl? up & down now works36 * correctly.37 * Modularization.38 * Alan Cox : Oops - fix AX.25 buffer lengths39 * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP40 * statistics. Include CSLIP code only41 * if it really needed.42 * Alan Cox : Free slhc buffers in the right place.43 * Alan Cox : Allow for digipeated IP over AX.2544 * Matti Aarnio : Dynamic SLIP devices, with ideas taken45 * from Jim Freeman's <jfree@caldera.com>46 * dynamic PPP devices. We do NOT kfree()47 * device entries, just reg./unreg. them48 * as they are needed. We kfree() them49 * at module cleanup.50 * With MODULE-loading ``insmod'', user51 * can issue parameter: slip_maxdev=102452 * (Or how much he/she wants.. Default53 * is 256)54 * Stanislav Voronyi : Slip line checking, with ideas taken55 * from multislip BSDI driver which was56 * written by Igor Chechik, RELCOM Corp.57 * Only algorithms have been ported to58 * Linux SLIP driver.59 * Vitaly E. Lavrov : Sane behaviour on tty hangup.60 * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice61 * modules.62 */63 64#define SL_CHECK_TRANSMIT65#include <linux/compat.h>66#include <linux/module.h>67#include <linux/moduleparam.h>68 69#include <linux/uaccess.h>70#include <linux/bitops.h>71#include <linux/sched/signal.h>72#include <linux/string.h>73#include <linux/mm.h>74#include <linux/interrupt.h>75#include <linux/in.h>76#include <linux/tty.h>77#include <linux/errno.h>78#include <linux/netdevice.h>79#include <linux/etherdevice.h>80#include <linux/skbuff.h>81#include <linux/rtnetlink.h>82#include <linux/if_arp.h>83#include <linux/if_slip.h>84#include <linux/delay.h>85#include <linux/init.h>86#include <linux/slab.h>87#include <linux/workqueue.h>88#include "slip.h"89#ifdef CONFIG_INET90#include <linux/ip.h>91#include <linux/tcp.h>92#include <net/slhc_vj.h>93#endif94 95#define SLIP_VERSION "0.8.4-NET3.019-NEWTTY"96 97static struct net_device **slip_devs;98 99static int slip_maxdev = SL_NRUNIT;100module_param(slip_maxdev, int, 0);101MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices");102 103static int slip_esc(unsigned char *p, unsigned char *d, int len);104static void slip_unesc(struct slip *sl, unsigned char c);105#ifdef CONFIG_SLIP_MODE_SLIP6106static int slip_esc6(unsigned char *p, unsigned char *d, int len);107static void slip_unesc6(struct slip *sl, unsigned char c);108#endif109#ifdef CONFIG_SLIP_SMART110static void sl_keepalive(struct timer_list *t);111static void sl_outfill(struct timer_list *t);112static int sl_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user *data, int cmd);113#endif114 115/********************************116* Buffer administration routines:117* sl_alloc_bufs()118* sl_free_bufs()119* sl_realloc_bufs()120*121* NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because122* sl_realloc_bufs provides strong atomicity and reallocation123* on actively running device.124*********************************/125 126/*127 Allocate channel buffers.128 */129 130static int sl_alloc_bufs(struct slip *sl, int mtu)131{132 int err = -ENOBUFS;133 unsigned long len;134 char *rbuff = NULL;135 char *xbuff = NULL;136#ifdef SL_INCLUDE_CSLIP137 char *cbuff = NULL;138 struct slcompress *slcomp = NULL;139#endif140 141 /*142 * Allocate the SLIP frame buffers:143 *144 * rbuff Receive buffer.145 * xbuff Transmit buffer.146 * cbuff Temporary compression buffer.147 */148 len = mtu * 2;149 150 /*151 * allow for arrival of larger UDP packets, even if we say not to152 * also fixes a bug in which SunOS sends 512-byte packets even with153 * an MSS of 128154 */155 if (len < 576 * 2)156 len = 576 * 2;157 rbuff = kmalloc(len + 4, GFP_KERNEL);158 if (rbuff == NULL)159 goto err_exit;160 xbuff = kmalloc(len + 4, GFP_KERNEL);161 if (xbuff == NULL)162 goto err_exit;163#ifdef SL_INCLUDE_CSLIP164 cbuff = kmalloc(len + 4, GFP_KERNEL);165 if (cbuff == NULL)166 goto err_exit;167 slcomp = slhc_init(16, 16);168 if (IS_ERR(slcomp))169 goto err_exit;170#endif171 spin_lock_bh(&sl->lock);172 if (sl->tty == NULL) {173 spin_unlock_bh(&sl->lock);174 err = -ENODEV;175 goto err_exit;176 }177 sl->mtu = mtu;178 sl->buffsize = len;179 sl->rcount = 0;180 sl->xleft = 0;181 rbuff = xchg(&sl->rbuff, rbuff);182 xbuff = xchg(&sl->xbuff, xbuff);183#ifdef SL_INCLUDE_CSLIP184 cbuff = xchg(&sl->cbuff, cbuff);185 slcomp = xchg(&sl->slcomp, slcomp);186#endif187#ifdef CONFIG_SLIP_MODE_SLIP6188 sl->xdata = 0;189 sl->xbits = 0;190#endif191 spin_unlock_bh(&sl->lock);192 err = 0;193 194 /* Cleanup */195err_exit:196#ifdef SL_INCLUDE_CSLIP197 kfree(cbuff);198 slhc_free(slcomp);199#endif200 kfree(xbuff);201 kfree(rbuff);202 return err;203}204 205/* Free a SLIP channel buffers. */206static void sl_free_bufs(struct slip *sl)207{208 /* Free all SLIP frame buffers. */209 kfree(xchg(&sl->rbuff, NULL));210 kfree(xchg(&sl->xbuff, NULL));211#ifdef SL_INCLUDE_CSLIP212 kfree(xchg(&sl->cbuff, NULL));213 slhc_free(xchg(&sl->slcomp, NULL));214#endif215}216 217/*218 Reallocate slip channel buffers.219 */220 221static int sl_realloc_bufs(struct slip *sl, int mtu)222{223 int err = 0;224 struct net_device *dev = sl->dev;225 unsigned char *xbuff, *rbuff;226#ifdef SL_INCLUDE_CSLIP227 unsigned char *cbuff;228#endif229 int len = mtu * 2;230 231/*232 * allow for arrival of larger UDP packets, even if we say not to233 * also fixes a bug in which SunOS sends 512-byte packets even with234 * an MSS of 128235 */236 if (len < 576 * 2)237 len = 576 * 2;238 239 xbuff = kmalloc(len + 4, GFP_ATOMIC);240 rbuff = kmalloc(len + 4, GFP_ATOMIC);241#ifdef SL_INCLUDE_CSLIP242 cbuff = kmalloc(len + 4, GFP_ATOMIC);243#endif244 245 246#ifdef SL_INCLUDE_CSLIP247 if (xbuff == NULL || rbuff == NULL || cbuff == NULL) {248#else249 if (xbuff == NULL || rbuff == NULL) {250#endif251 if (mtu > sl->mtu) {252 printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n",253 dev->name);254 err = -ENOBUFS;255 }256 goto done;257 }258 spin_lock_bh(&sl->lock);259 260 err = -ENODEV;261 if (sl->tty == NULL)262 goto done_on_bh;263 264 xbuff = xchg(&sl->xbuff, xbuff);265 rbuff = xchg(&sl->rbuff, rbuff);266#ifdef SL_INCLUDE_CSLIP267 cbuff = xchg(&sl->cbuff, cbuff);268#endif269 if (sl->xleft) {270 if (sl->xleft <= len) {271 memcpy(sl->xbuff, sl->xhead, sl->xleft);272 } else {273 sl->xleft = 0;274 dev->stats.tx_dropped++;275 }276 }277 sl->xhead = sl->xbuff;278 279 if (sl->rcount) {280 if (sl->rcount <= len) {281 memcpy(sl->rbuff, rbuff, sl->rcount);282 } else {283 sl->rcount = 0;284 dev->stats.rx_over_errors++;285 set_bit(SLF_ERROR, &sl->flags);286 }287 }288 sl->mtu = mtu;289 WRITE_ONCE(dev->mtu, mtu);290 sl->buffsize = len;291 err = 0;292 293done_on_bh:294 spin_unlock_bh(&sl->lock);295 296done:297 kfree(xbuff);298 kfree(rbuff);299#ifdef SL_INCLUDE_CSLIP300 kfree(cbuff);301#endif302 return err;303}304 305 306/* Set the "sending" flag. This must be atomic hence the set_bit. */307static inline void sl_lock(struct slip *sl)308{309 netif_stop_queue(sl->dev);310}311 312 313/* Clear the "sending" flag. This must be atomic, hence the ASM. */314static inline void sl_unlock(struct slip *sl)315{316 netif_wake_queue(sl->dev);317}318 319/* Send one completely decapsulated IP datagram to the IP layer. */320static void sl_bump(struct slip *sl)321{322 struct net_device *dev = sl->dev;323 struct sk_buff *skb;324 int count;325 326 count = sl->rcount;327#ifdef SL_INCLUDE_CSLIP328 if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) {329 unsigned char c = sl->rbuff[0];330 if (c & SL_TYPE_COMPRESSED_TCP) {331 /* ignore compressed packets when CSLIP is off */332 if (!(sl->mode & SL_MODE_CSLIP)) {333 printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name);334 return;335 }336 /* make sure we've reserved enough space for uncompress337 to use */338 if (count + 80 > sl->buffsize) {339 dev->stats.rx_over_errors++;340 return;341 }342 count = slhc_uncompress(sl->slcomp, sl->rbuff, count);343 if (count <= 0)344 return;345 } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) {346 if (!(sl->mode & SL_MODE_CSLIP)) {347 /* turn on header compression */348 sl->mode |= SL_MODE_CSLIP;349 sl->mode &= ~SL_MODE_ADAPTIVE;350 printk(KERN_INFO "%s: header compression turned on\n", dev->name);351 }352 sl->rbuff[0] &= 0x4f;353 if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0)354 return;355 }356 }357#endif /* SL_INCLUDE_CSLIP */358 359 dev->stats.rx_bytes += count;360 361 skb = dev_alloc_skb(count);362 if (skb == NULL) {363 printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name);364 dev->stats.rx_dropped++;365 return;366 }367 skb->dev = dev;368 skb_put_data(skb, sl->rbuff, count);369 skb_reset_mac_header(skb);370 skb->protocol = htons(ETH_P_IP);371 netif_rx(skb);372 dev->stats.rx_packets++;373}374 375/* Encapsulate one IP datagram and stuff into a TTY queue. */376static void sl_encaps(struct slip *sl, unsigned char *icp, int len)377{378 unsigned char *p;379 int actual, count;380 381 if (len > sl->mtu) { /* Sigh, shouldn't occur BUT ... */382 printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name);383 sl->dev->stats.tx_dropped++;384 sl_unlock(sl);385 return;386 }387 388 p = icp;389#ifdef SL_INCLUDE_CSLIP390 if (sl->mode & SL_MODE_CSLIP)391 len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1);392#endif393#ifdef CONFIG_SLIP_MODE_SLIP6394 if (sl->mode & SL_MODE_SLIP6)395 count = slip_esc6(p, sl->xbuff, len);396 else397#endif398 count = slip_esc(p, sl->xbuff, len);399 400 /* Order of next two lines is *very* important.401 * When we are sending a little amount of data,402 * the transfer may be completed inside the ops->write()403 * routine, because it's running with interrupts enabled.404 * In this case we *never* got WRITE_WAKEUP event,405 * if we did not request it before write operation.406 * 14 Oct 1994 Dmitry Gorodchanin.407 */408 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);409 actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);410#ifdef SL_CHECK_TRANSMIT411 netif_trans_update(sl->dev);412#endif413 sl->xleft = count - actual;414 sl->xhead = sl->xbuff + actual;415#ifdef CONFIG_SLIP_SMART416 /* VSV */417 clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */418#endif419}420 421/* Write out any remaining transmit buffer. Scheduled when tty is writable */422static void slip_transmit(struct work_struct *work)423{424 struct slip *sl = container_of(work, struct slip, tx_work);425 int actual;426 427 spin_lock_bh(&sl->lock);428 /* First make sure we're connected. */429 if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {430 spin_unlock_bh(&sl->lock);431 return;432 }433 434 if (sl->xleft <= 0) {435 /* Now serial buffer is almost free & we can start436 * transmission of another packet */437 sl->dev->stats.tx_packets++;438 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);439 spin_unlock_bh(&sl->lock);440 sl_unlock(sl);441 return;442 }443 444 actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);445 sl->xleft -= actual;446 sl->xhead += actual;447 spin_unlock_bh(&sl->lock);448}449 450/*451 * Called by the driver when there's room for more data.452 * Schedule the transmit.453 */454static void slip_write_wakeup(struct tty_struct *tty)455{456 struct slip *sl;457 458 rcu_read_lock();459 sl = rcu_dereference(tty->disc_data);460 if (sl)461 schedule_work(&sl->tx_work);462 rcu_read_unlock();463}464 465static void sl_tx_timeout(struct net_device *dev, unsigned int txqueue)466{467 struct slip *sl = netdev_priv(dev);468 469 spin_lock(&sl->lock);470 471 if (netif_queue_stopped(dev)) {472 if (!netif_running(dev) || !sl->tty)473 goto out;474 475 /* May be we must check transmitter timeout here ?476 * 14 Oct 1994 Dmitry Gorodchanin.477 */478#ifdef SL_CHECK_TRANSMIT479 if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) {480 /* 20 sec timeout not reached */481 goto out;482 }483 printk(KERN_WARNING "%s: transmit timed out, %s?\n",484 dev->name,485 (tty_chars_in_buffer(sl->tty) || sl->xleft) ?486 "bad line quality" : "driver error");487 sl->xleft = 0;488 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);489 sl_unlock(sl);490#endif491 }492out:493 spin_unlock(&sl->lock);494}495 496 497/* Encapsulate an IP datagram and kick it into a TTY queue. */498static netdev_tx_t499sl_xmit(struct sk_buff *skb, struct net_device *dev)500{501 struct slip *sl = netdev_priv(dev);502 503 spin_lock(&sl->lock);504 if (!netif_running(dev)) {505 spin_unlock(&sl->lock);506 printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name);507 dev_kfree_skb(skb);508 return NETDEV_TX_OK;509 }510 if (sl->tty == NULL) {511 spin_unlock(&sl->lock);512 dev_kfree_skb(skb);513 return NETDEV_TX_OK;514 }515 516 sl_lock(sl);517 dev->stats.tx_bytes += skb->len;518 sl_encaps(sl, skb->data, skb->len);519 spin_unlock(&sl->lock);520 521 dev_kfree_skb(skb);522 return NETDEV_TX_OK;523}524 525 526/******************************************527 * Routines looking at netdevice side.528 ******************************************/529 530/* Netdevice UP -> DOWN routine */531 532static int533sl_close(struct net_device *dev)534{535 struct slip *sl = netdev_priv(dev);536 537 spin_lock_bh(&sl->lock);538 if (sl->tty)539 /* TTY discipline is running. */540 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);541 netif_stop_queue(dev);542 sl->rcount = 0;543 sl->xleft = 0;544 spin_unlock_bh(&sl->lock);545 546 return 0;547}548 549/* Netdevice DOWN -> UP routine */550 551static int sl_open(struct net_device *dev)552{553 struct slip *sl = netdev_priv(dev);554 555 if (sl->tty == NULL)556 return -ENODEV;557 558 sl->flags &= (1 << SLF_INUSE);559 netif_start_queue(dev);560 return 0;561}562 563/* Netdevice change MTU request */564 565static int sl_change_mtu(struct net_device *dev, int new_mtu)566{567 struct slip *sl = netdev_priv(dev);568 569 return sl_realloc_bufs(sl, new_mtu);570}571 572/* Netdevice get statistics request */573 574static void575sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)576{577 struct net_device_stats *devstats = &dev->stats;578#ifdef SL_INCLUDE_CSLIP579 struct slip *sl = netdev_priv(dev);580 struct slcompress *comp = sl->slcomp;581#endif582 stats->rx_packets = devstats->rx_packets;583 stats->tx_packets = devstats->tx_packets;584 stats->rx_bytes = devstats->rx_bytes;585 stats->tx_bytes = devstats->tx_bytes;586 stats->rx_dropped = devstats->rx_dropped;587 stats->tx_dropped = devstats->tx_dropped;588 stats->tx_errors = devstats->tx_errors;589 stats->rx_errors = devstats->rx_errors;590 stats->rx_over_errors = devstats->rx_over_errors;591 592#ifdef SL_INCLUDE_CSLIP593 if (comp) {594 /* Generic compressed statistics */595 stats->rx_compressed = comp->sls_i_compressed;596 stats->tx_compressed = comp->sls_o_compressed;597 598 /* Are we really still needs this? */599 stats->rx_fifo_errors += comp->sls_i_compressed;600 stats->rx_dropped += comp->sls_i_tossed;601 stats->tx_fifo_errors += comp->sls_o_compressed;602 stats->collisions += comp->sls_o_misses;603 }604#endif605}606 607/* Netdevice register callback */608 609static int sl_init(struct net_device *dev)610{611 struct slip *sl = netdev_priv(dev);612 613 /*614 * Finish setting up the DEVICE info.615 */616 617 dev->mtu = sl->mtu;618 dev->type = ARPHRD_SLIP + sl->mode;619#ifdef SL_CHECK_TRANSMIT620 dev->watchdog_timeo = 20*HZ;621#endif622 return 0;623}624 625 626static void sl_uninit(struct net_device *dev)627{628 struct slip *sl = netdev_priv(dev);629 630 sl_free_bufs(sl);631}632 633/* Hook the destructor so we can free slip devices at the right point in time */634static void sl_free_netdev(struct net_device *dev)635{636 int i = dev->base_addr;637 638 slip_devs[i] = NULL;639}640 641static const struct net_device_ops sl_netdev_ops = {642 .ndo_init = sl_init,643 .ndo_uninit = sl_uninit,644 .ndo_open = sl_open,645 .ndo_stop = sl_close,646 .ndo_start_xmit = sl_xmit,647 .ndo_get_stats64 = sl_get_stats64,648 .ndo_change_mtu = sl_change_mtu,649 .ndo_tx_timeout = sl_tx_timeout,650#ifdef CONFIG_SLIP_SMART651 .ndo_siocdevprivate = sl_siocdevprivate,652#endif653};654 655 656static void sl_setup(struct net_device *dev)657{658 dev->netdev_ops = &sl_netdev_ops;659 dev->needs_free_netdev = true;660 dev->priv_destructor = sl_free_netdev;661 662 dev->hard_header_len = 0;663 dev->addr_len = 0;664 dev->tx_queue_len = 10;665 666 /* MTU range: 68 - 65534 */667 dev->min_mtu = 68;668 dev->max_mtu = 65534;669 670 /* New-style flags. */671 dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST;672}673 674/******************************************675 Routines looking at TTY side.676 ******************************************/677 678 679/*680 * Handle the 'receiver data ready' interrupt.681 * This function is called by the 'tty_io' module in the kernel when682 * a block of SLIP data has been received, which can now be decapsulated683 * and sent on to some IP layer for further processing. This will not684 * be re-entered while running but other ldisc functions may be called685 * in parallel686 */687 688static void slip_receive_buf(struct tty_struct *tty, const u8 *cp, const u8 *fp,689 size_t count)690{691 struct slip *sl = tty->disc_data;692 693 if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))694 return;695 696 /* Read the characters out of the buffer */697 while (count--) {698 if (fp && *fp++) {699 if (!test_and_set_bit(SLF_ERROR, &sl->flags))700 sl->dev->stats.rx_errors++;701 cp++;702 continue;703 }704#ifdef CONFIG_SLIP_MODE_SLIP6705 if (sl->mode & SL_MODE_SLIP6)706 slip_unesc6(sl, *cp++);707 else708#endif709 slip_unesc(sl, *cp++);710 }711}712 713/************************************714 * slip_open helper routines.715 ************************************/716 717/* Collect hanged up channels */718static void sl_sync(void)719{720 int i;721 struct net_device *dev;722 struct slip *sl;723 724 for (i = 0; i < slip_maxdev; i++) {725 dev = slip_devs[i];726 if (dev == NULL)727 break;728 729 sl = netdev_priv(dev);730 if (sl->tty || sl->leased)731 continue;732 if (dev->flags & IFF_UP)733 dev_close(dev);734 }735}736 737 738/* Find a free SLIP channel, and link in this `tty' line. */739static struct slip *sl_alloc(void)740{741 int i;742 char name[IFNAMSIZ];743 struct net_device *dev = NULL;744 struct slip *sl;745 746 for (i = 0; i < slip_maxdev; i++) {747 dev = slip_devs[i];748 if (dev == NULL)749 break;750 }751 /* Sorry, too many, all slots in use */752 if (i >= slip_maxdev)753 return NULL;754 755 sprintf(name, "sl%d", i);756 dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup);757 if (!dev)758 return NULL;759 760 dev->base_addr = i;761 sl = netdev_priv(dev);762 763 /* Initialize channel control data */764 sl->magic = SLIP_MAGIC;765 sl->dev = dev;766 spin_lock_init(&sl->lock);767 INIT_WORK(&sl->tx_work, slip_transmit);768 sl->mode = SL_MODE_DEFAULT;769#ifdef CONFIG_SLIP_SMART770 /* initialize timer_list struct */771 timer_setup(&sl->keepalive_timer, sl_keepalive, 0);772 timer_setup(&sl->outfill_timer, sl_outfill, 0);773#endif774 slip_devs[i] = dev;775 return sl;776}777 778/*779 * Open the high-level part of the SLIP channel.780 * This function is called by the TTY module when the781 * SLIP line discipline is called for. Because we are782 * sure the tty line exists, we only have to link it to783 * a free SLIP channel...784 *785 * Called in process context serialized from other ldisc calls.786 */787 788static int slip_open(struct tty_struct *tty)789{790 struct slip *sl;791 int err;792 793 if (!capable(CAP_NET_ADMIN))794 return -EPERM;795 796 if (tty->ops->write == NULL)797 return -EOPNOTSUPP;798 799 /* RTnetlink lock is misused here to serialize concurrent800 opens of slip channels. There are better ways, but it is801 the simplest one.802 */803 rtnl_lock();804 805 /* Collect hanged up channels. */806 sl_sync();807 808 sl = tty->disc_data;809 810 err = -EEXIST;811 /* First make sure we're not already connected. */812 if (sl && sl->magic == SLIP_MAGIC)813 goto err_exit;814 815 /* OK. Find a free SLIP channel to use. */816 err = -ENFILE;817 sl = sl_alloc();818 if (sl == NULL)819 goto err_exit;820 821 sl->tty = tty;822 tty->disc_data = sl;823 sl->pid = current->pid;824 825 if (!test_bit(SLF_INUSE, &sl->flags)) {826 /* Perform the low-level SLIP initialization. */827 err = sl_alloc_bufs(sl, SL_MTU);828 if (err)829 goto err_free_chan;830 831 set_bit(SLF_INUSE, &sl->flags);832 833 err = register_netdevice(sl->dev);834 if (err)835 goto err_free_bufs;836 }837 838#ifdef CONFIG_SLIP_SMART839 if (sl->keepalive) {840 sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ;841 add_timer(&sl->keepalive_timer);842 }843 if (sl->outfill) {844 sl->outfill_timer.expires = jiffies + sl->outfill * HZ;845 add_timer(&sl->outfill_timer);846 }847#endif848 849 /* Done. We have linked the TTY line to a channel. */850 rtnl_unlock();851 tty->receive_room = 65536; /* We don't flow control */852 853 /* TTY layer expects 0 on success */854 return 0;855 856err_free_bufs:857 sl_free_bufs(sl);858 859err_free_chan:860 sl->tty = NULL;861 tty->disc_data = NULL;862 clear_bit(SLF_INUSE, &sl->flags);863 sl_free_netdev(sl->dev);864 /* do not call free_netdev before rtnl_unlock */865 rtnl_unlock();866 free_netdev(sl->dev);867 return err;868 869err_exit:870 rtnl_unlock();871 872 /* Count references from TTY module */873 return err;874}875 876/*877 * Close down a SLIP channel.878 * This means flushing out any pending queues, and then returning. This879 * call is serialized against other ldisc functions.880 *881 * We also use this method fo a hangup event882 */883 884static void slip_close(struct tty_struct *tty)885{886 struct slip *sl = tty->disc_data;887 888 /* First make sure we're connected. */889 if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)890 return;891 892 spin_lock_bh(&sl->lock);893 rcu_assign_pointer(tty->disc_data, NULL);894 sl->tty = NULL;895 spin_unlock_bh(&sl->lock);896 897 synchronize_rcu();898 flush_work(&sl->tx_work);899 900 /* VSV = very important to remove timers */901#ifdef CONFIG_SLIP_SMART902 del_timer_sync(&sl->keepalive_timer);903 del_timer_sync(&sl->outfill_timer);904#endif905 /* Flush network side */906 unregister_netdev(sl->dev);907 /* This will complete via sl_free_netdev */908}909 910static void slip_hangup(struct tty_struct *tty)911{912 slip_close(tty);913}914 /************************************************************************915 * STANDARD SLIP ENCAPSULATION *916 ************************************************************************/917 918static 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 any925 * data that may have accumulated in the receiver926 * due to line noise.927 */928 929 *ptr++ = END;930 931 /*932 * For each byte in the packet, send the appropriate933 * 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 955static void slip_unesc(struct slip *sl, unsigned char s)956{957 958 switch (s) {959 case END:960#ifdef CONFIG_SLIP_SMART961 /* drop keeptest bit = VSV */962 if (test_bit(SLF_KEEPTEST, &sl->flags))963 clear_bit(SLF_KEEPTEST, &sl->flags);964#endif965 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_SLIP6997/************************************************************************998 * 6 BIT SLIP ENCAPSULATION *999 ************************************************************************/1000 1001static 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 any1011 * data that may have accumulated in the receiver1012 * due to line noise.1013 */1014 1015 *ptr++ = 0x70;1016 1017 /*1018 * Encode the packet into printable ascii characters1019 */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 1038static void slip_unesc6(struct slip *sl, unsigned char s)1039{1040 unsigned char c;1041 1042 if (s == 0x70) {1043#ifdef CONFIG_SLIP_SMART1044 /* drop keeptest bit = VSV */1045 if (test_bit(SLF_KEEPTEST, &sl->flags))1046 clear_bit(SLF_KEEPTEST, &sl->flags);1047#endif1048 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. */1075static int slip_ioctl(struct tty_struct *tty, unsigned int cmd,1076 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_CSLIP1102 if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE))1103 return -EINVAL;1104#else1105 if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) ==1106 (SL_MODE_ADAPTIVE | SL_MODE_CSLIP))1107 /* return -EINVAL; */1108 tmp &= ~SL_MODE_ADAPTIVE;1109#endif1110#ifndef CONFIG_SLIP_MODE_SLIP61111 if (tmp & SL_MODE_SLIP6)1112 return -EINVAL;1113#endif1114 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_SMART1122 /* 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 } else1140 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 } else1165 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#endif1175 default:1176 return tty_mode_ioctl(tty, cmd, arg);1177 }1178}1179 1180/* VSV changes start here */1181#ifdef CONFIG_SLIP_SMART1182/* function sl_siocdevprivate called from net/core/dev.c1183 to allow get/set outfill/keepalive parameter1184 by ifconfig */1185 1186static int sl_siocdevprivate(struct net_device *dev, struct ifreq *rq,1187 void __user *data, int cmd)1188{1189 struct slip *sl = netdev_priv(dev);1190 unsigned long *p = (unsigned long *)&rq->ifr_ifru;1191 1192 if (sl == NULL) /* Allocation failed ?? */1193 return -ENODEV;1194 1195 if (in_compat_syscall())1196 return -EOPNOTSUPP;1197 1198 spin_lock_bh(&sl->lock);1199 1200 if (!sl->tty) {1201 spin_unlock_bh(&sl->lock);1202 return -ENODEV;1203 }1204 1205 switch (cmd) {1206 case SIOCSKEEPALIVE:1207 /* max for unchar */1208 if ((unsigned)*p > 255) {1209 spin_unlock_bh(&sl->lock);1210 return -EINVAL;1211 }1212 sl->keepalive = (u8)*p;1213 if (sl->keepalive != 0) {1214 sl->keepalive_timer.expires =1215 jiffies + sl->keepalive * HZ;1216 mod_timer(&sl->keepalive_timer,1217 jiffies + sl->keepalive * HZ);1218 set_bit(SLF_KEEPTEST, &sl->flags);1219 } else1220 del_timer(&sl->keepalive_timer);1221 break;1222 1223 case SIOCGKEEPALIVE:1224 *p = sl->keepalive;1225 break;1226 1227 case SIOCSOUTFILL:1228 if ((unsigned)*p > 255) { /* max for unchar */1229 spin_unlock_bh(&sl->lock);1230 return -EINVAL;1231 }1232 sl->outfill = (u8)*p;1233 if (sl->outfill != 0) {1234 mod_timer(&sl->outfill_timer,1235 jiffies + sl->outfill * HZ);1236 set_bit(SLF_OUTWAIT, &sl->flags);1237 } else1238 del_timer(&sl->outfill_timer);1239 break;1240 1241 case SIOCGOUTFILL:1242 *p = sl->outfill;1243 break;1244 1245 case SIOCSLEASE:1246 /* Resolve race condition, when ioctl'ing hanged up1247 and opened by another process device.1248 */1249 if (sl->tty != current->signal->tty &&1250 sl->pid != current->pid) {1251 spin_unlock_bh(&sl->lock);1252 return -EPERM;1253 }1254 sl->leased = 0;1255 if (*p)1256 sl->leased = 1;1257 break;1258 1259 case SIOCGLEASE:1260 *p = sl->leased;1261 }1262 spin_unlock_bh(&sl->lock);1263 return 0;1264}1265#endif1266/* VSV changes end */1267 1268static struct tty_ldisc_ops sl_ldisc = {1269 .owner = THIS_MODULE,1270 .num = N_SLIP,1271 .name = "slip",1272 .open = slip_open,1273 .close = slip_close,1274 .hangup = slip_hangup,1275 .ioctl = slip_ioctl,1276 .receive_buf = slip_receive_buf,1277 .write_wakeup = slip_write_wakeup,1278};1279 1280static int __init slip_init(void)1281{1282 int status;1283 1284 if (slip_maxdev < 4)1285 slip_maxdev = 4; /* Sanity */1286 1287 printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)"1288#ifdef CONFIG_SLIP_MODE_SLIP61289 " (6 bit encapsulation enabled)"1290#endif1291 ".\n",1292 SLIP_VERSION, slip_maxdev);1293#if defined(SL_INCLUDE_CSLIP)1294 printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n");1295#endif1296#ifdef CONFIG_SLIP_SMART1297 printk(KERN_INFO "SLIP linefill/keepalive option.\n");1298#endif1299 1300 slip_devs = kcalloc(slip_maxdev, sizeof(struct net_device *),1301 GFP_KERNEL);1302 if (!slip_devs)1303 return -ENOMEM;1304 1305 /* Fill in our line protocol discipline, and register it */1306 status = tty_register_ldisc(&sl_ldisc);1307 if (status != 0) {1308 printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status);1309 kfree(slip_devs);1310 }1311 return status;1312}1313 1314static void __exit slip_exit(void)1315{1316 int i;1317 struct net_device *dev;1318 struct slip *sl;1319 unsigned long timeout = jiffies + HZ;1320 int busy = 0;1321 1322 if (slip_devs == NULL)1323 return;1324 1325 /* First of all: check for active disciplines and hangup them.1326 */1327 do {1328 if (busy)1329 msleep_interruptible(100);1330 1331 busy = 0;1332 for (i = 0; i < slip_maxdev; i++) {1333 dev = slip_devs[i];1334 if (!dev)1335 continue;1336 sl = netdev_priv(dev);1337 spin_lock_bh(&sl->lock);1338 if (sl->tty) {1339 busy++;1340 tty_hangup(sl->tty);1341 }1342 spin_unlock_bh(&sl->lock);1343 }1344 } while (busy && time_before(jiffies, timeout));1345 1346 /* FIXME: hangup is async so we should wait when doing this second1347 phase */1348 1349 for (i = 0; i < slip_maxdev; i++) {1350 dev = slip_devs[i];1351 if (!dev)1352 continue;1353 slip_devs[i] = NULL;1354 1355 sl = netdev_priv(dev);1356 if (sl->tty) {1357 printk(KERN_ERR "%s: tty discipline still running\n",1358 dev->name);1359 }1360 1361 unregister_netdev(dev);1362 }1363 1364 kfree(slip_devs);1365 slip_devs = NULL;1366 1367 tty_unregister_ldisc(&sl_ldisc);1368}1369 1370module_init(slip_init);1371module_exit(slip_exit);1372 1373#ifdef CONFIG_SLIP_SMART1374/*1375 * This is start of the code for multislip style line checking1376 * added by Stanislav Voronyi. All changes before marked VSV1377 */1378 1379static void sl_outfill(struct timer_list *t)1380{1381 struct slip *sl = from_timer(sl, t, outfill_timer);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_SLIP61392 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END;1393#else1394 unsigned char s = END;1395#endif1396 /* 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 } else1402 set_bit(SLF_OUTWAIT, &sl->flags);1403 1404 mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ);1405 }1406out:1407 spin_unlock(&sl->lock);1408}1409 1410static void sl_keepalive(struct timer_list *t)1411{1412 struct slip *sl = from_timer(sl, t, keepalive_timer);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 } else1431 set_bit(SLF_KEEPTEST, &sl->flags);1432 1433 mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ);1434 }1435out:1436 spin_unlock(&sl->lock);1437}1438 1439#endif1440MODULE_DESCRIPTION("SLIP (serial line) protocol module");1441MODULE_LICENSE("GPL");1442MODULE_ALIAS_LDISC(N_SLIP);1443