// SPDX-License-Identifier: GPL-2.0-only /* * slip.c This module implements the SLIP protocol for kernel-based * devices like TTY. It interfaces between a raw TTY, and the * kernel's INET protocol layers. * * Version: @(#)slip.c 0.8.3 12/24/94 * * Authors: Laurence Culhane, * Fred N. van Kempen, * * Fixes: * Alan Cox : Sanity checks and avoid tx overruns. * Has a new sl->mtu field. * Alan Cox : Found cause of overrun. ifconfig sl0 * mtu upwards. Driver now spots this * and grows/shrinks its buffers(hack!). * Memory leak if you run out of memory * setting up a slip driver fixed. * Matt Dillon : Printable slip (borrowed from NET2E) * Pauline Middelink : Slip driver fixes. * Alan Cox : Honours the old SL_COMPRESSED flag * Alan Cox : KISS AX.25 and AXUI IP support * Michael Riepe : Automatic CSLIP recognition added * Charles Hedrick : CSLIP header length problem fix. * Alan Cox : Corrected non-IP cases of the above. * Alan Cox : Now uses hardware type as per FvK. * Alan Cox : Default to 192.168.0.0 (RFC 1597) * A.N.Kuznetsov : dev_tint() recursion fix. * Dmitry Gorodchanin : SLIP memory leaks * Dmitry Gorodchanin : Code cleanup. Reduce tty driver * buffering from 4096 to 256 bytes. * Improving SLIP response time. * CONFIG_SLIP_MODE_SLIP6. * ifconfig sl? up & down now works * correctly. * Modularization. * Alan Cox : Oops - fix AX.25 buffer lengths * Dmitry Gorodchanin : Even more cleanups. Preserve CSLIP * statistics. Include CSLIP code only * if it really needed. * Alan Cox : Free slhc buffers in the right place. * Alan Cox : Allow for digipeated IP over AX.25 * Matti Aarnio : Dynamic SLIP devices, with ideas taken * from Jim Freeman's * dynamic PPP devices. We do NOT kfree() * device entries, just reg./unreg. them * as they are needed. We kfree() them * at module cleanup. * With MODULE-loading ``insmod'', user * can issue parameter: slip_maxdev=1024 * (Or how much he/she wants.. Default * is 256) * Stanislav Voronyi : Slip line checking, with ideas taken * from multislip BSDI driver which was * written by Igor Chechik, RELCOM Corp. * Only algorithms have been ported to * Linux SLIP driver. * Vitaly E. Lavrov : Sane behaviour on tty hangup. * Alexey Kuznetsov : Cleanup interfaces to tty & netdevice * modules. */ #define SL_CHECK_TRANSMIT #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "slip.h" #ifdef CONFIG_INET #include #include #include #endif #define SLIP_VERSION "0.8.4-NET3.019-NEWTTY" static struct net_device **slip_devs; static int slip_maxdev = SL_NRUNIT; module_param(slip_maxdev, int, 0); MODULE_PARM_DESC(slip_maxdev, "Maximum number of slip devices"); static int slip_esc(unsigned char *p, unsigned char *d, int len); static void slip_unesc(struct slip *sl, unsigned char c); #ifdef CONFIG_SLIP_MODE_SLIP6 static int slip_esc6(unsigned char *p, unsigned char *d, int len); static void slip_unesc6(struct slip *sl, unsigned char c); #endif #ifdef CONFIG_SLIP_SMART static void sl_keepalive(struct timer_list *t); static void sl_outfill(struct timer_list *t); static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd); #endif /******************************** * Buffer administration routines: * sl_alloc_bufs() * sl_free_bufs() * sl_realloc_bufs() * * NOTE: sl_realloc_bufs != sl_free_bufs + sl_alloc_bufs, because * sl_realloc_bufs provides strong atomicity and reallocation * on actively running device. *********************************/ /* Allocate channel buffers. */ static int sl_alloc_bufs(struct slip *sl, int mtu) { int err = -ENOBUFS; unsigned long len; char *rbuff = NULL; char *xbuff = NULL; #ifdef SL_INCLUDE_CSLIP char *cbuff = NULL; struct slcompress *slcomp = NULL; #endif /* * Allocate the SLIP frame buffers: * * rbuff Receive buffer. * xbuff Transmit buffer. * cbuff Temporary compression buffer. */ len = mtu * 2; /* * allow for arrival of larger UDP packets, even if we say not to * also fixes a bug in which SunOS sends 512-byte packets even with * an MSS of 128 */ if (len < 576 * 2) len = 576 * 2; rbuff = kmalloc(len + 4, GFP_KERNEL); if (rbuff == NULL) goto err_exit; xbuff = kmalloc(len + 4, GFP_KERNEL); if (xbuff == NULL) goto err_exit; #ifdef SL_INCLUDE_CSLIP cbuff = kmalloc(len + 4, GFP_KERNEL); if (cbuff == NULL) goto err_exit; slcomp = slhc_init(16, 16); if (IS_ERR(slcomp)) goto err_exit; #endif spin_lock_bh(&sl->lock); if (sl->tty == NULL) { spin_unlock_bh(&sl->lock); err = -ENODEV; goto err_exit; } sl->mtu = mtu; sl->buffsize = len; sl->rcount = 0; sl->xleft = 0; rbuff = xchg(&sl->rbuff, rbuff); xbuff = xchg(&sl->xbuff, xbuff); #ifdef SL_INCLUDE_CSLIP cbuff = xchg(&sl->cbuff, cbuff); slcomp = xchg(&sl->slcomp, slcomp); #endif #ifdef CONFIG_SLIP_MODE_SLIP6 sl->xdata = 0; sl->xbits = 0; #endif spin_unlock_bh(&sl->lock); err = 0; /* Cleanup */ err_exit: #ifdef SL_INCLUDE_CSLIP kfree(cbuff); slhc_free(slcomp); #endif kfree(xbuff); kfree(rbuff); return err; } /* Free a SLIP channel buffers. */ static void sl_free_bufs(struct slip *sl) { /* Free all SLIP frame buffers. */ kfree(xchg(&sl->rbuff, NULL)); kfree(xchg(&sl->xbuff, NULL)); #ifdef SL_INCLUDE_CSLIP kfree(xchg(&sl->cbuff, NULL)); slhc_free(xchg(&sl->slcomp, NULL)); #endif } /* Reallocate slip channel buffers. */ static int sl_realloc_bufs(struct slip *sl, int mtu) { int err = 0; struct net_device *dev = sl->dev; unsigned char *xbuff, *rbuff; #ifdef SL_INCLUDE_CSLIP unsigned char *cbuff; #endif int len = mtu * 2; /* * allow for arrival of larger UDP packets, even if we say not to * also fixes a bug in which SunOS sends 512-byte packets even with * an MSS of 128 */ if (len < 576 * 2) len = 576 * 2; xbuff = kmalloc(len + 4, GFP_ATOMIC); rbuff = kmalloc(len + 4, GFP_ATOMIC); #ifdef SL_INCLUDE_CSLIP cbuff = kmalloc(len + 4, GFP_ATOMIC); #endif #ifdef SL_INCLUDE_CSLIP if (xbuff == NULL || rbuff == NULL || cbuff == NULL) { #else if (xbuff == NULL || rbuff == NULL) { #endif if (mtu > sl->mtu) { printk(KERN_WARNING "%s: unable to grow slip buffers, MTU change cancelled.\n", dev->name); err = -ENOBUFS; } goto done; } spin_lock_bh(&sl->lock); err = -ENODEV; if (sl->tty == NULL) goto done_on_bh; xbuff = xchg(&sl->xbuff, xbuff); rbuff = xchg(&sl->rbuff, rbuff); #ifdef SL_INCLUDE_CSLIP cbuff = xchg(&sl->cbuff, cbuff); #endif if (sl->xleft) { if (sl->xleft <= len) { memcpy(sl->xbuff, sl->xhead, sl->xleft); } else { sl->xleft = 0; dev->stats.tx_dropped++; } } sl->xhead = sl->xbuff; if (sl->rcount) { if (sl->rcount <= len) { memcpy(sl->rbuff, rbuff, sl->rcount); } else { sl->rcount = 0; dev->stats.rx_over_errors++; set_bit(SLF_ERROR, &sl->flags); } } sl->mtu = mtu; dev->mtu = mtu; sl->buffsize = len; err = 0; done_on_bh: spin_unlock_bh(&sl->lock); done: kfree(xbuff); kfree(rbuff); #ifdef SL_INCLUDE_CSLIP kfree(cbuff); #endif return err; } /* Set the "sending" flag. This must be atomic hence the set_bit. */ static inline void sl_lock(struct slip *sl) { netif_stop_queue(sl->dev); } /* Clear the "sending" flag. This must be atomic, hence the ASM. */ static inline void sl_unlock(struct slip *sl) { netif_wake_queue(sl->dev); } /* Send one completely decapsulated IP datagram to the IP layer. */ static void sl_bump(struct slip *sl) { struct net_device *dev = sl->dev; struct sk_buff *skb; int count; count = sl->rcount; #ifdef SL_INCLUDE_CSLIP if (sl->mode & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) { unsigned char c = sl->rbuff[0]; if (c & SL_TYPE_COMPRESSED_TCP) { /* ignore compressed packets when CSLIP is off */ if (!(sl->mode & SL_MODE_CSLIP)) { printk(KERN_WARNING "%s: compressed packet ignored\n", dev->name); return; } /* make sure we've reserved enough space for uncompress to use */ if (count + 80 > sl->buffsize) { dev->stats.rx_over_errors++; return; } count = slhc_uncompress(sl->slcomp, sl->rbuff, count); if (count <= 0) return; } else if (c >= SL_TYPE_UNCOMPRESSED_TCP) { if (!(sl->mode & SL_MODE_CSLIP)) { /* turn on header compression */ sl->mode |= SL_MODE_CSLIP; sl->mode &= ~SL_MODE_ADAPTIVE; printk(KERN_INFO "%s: header compression turned on\n", dev->name); } sl->rbuff[0] &= 0x4f; if (slhc_remember(sl->slcomp, sl->rbuff, count) <= 0) return; } } #endif /* SL_INCLUDE_CSLIP */ dev->stats.rx_bytes += count; skb = dev_alloc_skb(count); if (skb == NULL) { printk(KERN_WARNING "%s: memory squeeze, dropping packet.\n", dev->name); dev->stats.rx_dropped++; return; } skb->dev = dev; skb_put_data(skb, sl->rbuff, count); skb_reset_mac_header(skb); skb->protocol = htons(ETH_P_IP); netif_rx_ni(skb); dev->stats.rx_packets++; } /* Encapsulate one IP datagram and stuff into a TTY queue. */ static void sl_encaps(struct slip *sl, unsigned char *icp, int len) { unsigned char *p; int actual, count; if (len > sl->mtu) { /* Sigh, shouldn't occur BUT ... */ printk(KERN_WARNING "%s: truncating oversized transmit packet!\n", sl->dev->name); sl->dev->stats.tx_dropped++; sl_unlock(sl); return; } p = icp; #ifdef SL_INCLUDE_CSLIP if (sl->mode & SL_MODE_CSLIP) len = slhc_compress(sl->slcomp, p, len, sl->cbuff, &p, 1); #endif #ifdef CONFIG_SLIP_MODE_SLIP6 if (sl->mode & SL_MODE_SLIP6) count = slip_esc6(p, sl->xbuff, len); else #endif count = slip_esc(p, sl->xbuff, len); /* Order of next two lines is *very* important. * When we are sending a little amount of data, * the transfer may be completed inside the ops->write() * routine, because it's running with interrupts enabled. * In this case we *never* got WRITE_WAKEUP event, * if we did not request it before write operation. * 14 Oct 1994 Dmitry Gorodchanin. */ set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); actual = sl->tty->ops->write(sl->tty, sl->xbuff, count); #ifdef SL_CHECK_TRANSMIT netif_trans_update(sl->dev); #endif sl->xleft = count - actual; sl->xhead = sl->xbuff + actual; #ifdef CONFIG_SLIP_SMART /* VSV */ clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */ #endif } /* Write out any remaining transmit buffer. Scheduled when tty is writable */ static void slip_transmit(struct work_struct *work) { struct slip *sl = container_of(work, struct slip, tx_work); int actual; spin_lock_bh(&sl->lock); /* First make sure we're connected. */ if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) { spin_unlock_bh(&sl->lock); return; } if (sl->xleft <= 0) { /* Now serial buffer is almost free & we can start * transmission of another packet */ sl->dev->stats.tx_packets++; clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); spin_unlock_bh(&sl->lock); sl_unlock(sl); return; } actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft); sl->xleft -= actual; sl->xhead += actual; spin_unlock_bh(&sl->lock); } /* * Called by the driver when there's room for more data. * Schedule the transmit. */ static void slip_write_wakeup(struct tty_struct *tty) { struct slip *sl; rcu_read_lock(); sl = rcu_dereference(tty->disc_data); if (!sl) goto out; schedule_work(&sl->tx_work); out: rcu_read_unlock(); } static void sl_tx_timeout(struct net_device *dev, unsigned int txqueue) { struct slip *sl = netdev_priv(dev); spin_lock(&sl->lock); if (netif_queue_stopped(dev)) { if (!netif_running(dev)) goto out; /* May be we must check transmitter timeout here ? * 14 Oct 1994 Dmitry Gorodchanin. */ #ifdef SL_CHECK_TRANSMIT if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) { /* 20 sec timeout not reached */ goto out; } printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name, (tty_chars_in_buffer(sl->tty) || sl->xleft) ? "bad line quality" : "driver error"); sl->xleft = 0; clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); sl_unlock(sl); #endif } out: spin_unlock(&sl->lock); } /* Encapsulate an IP datagram and kick it into a TTY queue. */ static netdev_tx_t sl_xmit(struct sk_buff *skb, struct net_device *dev) { struct slip *sl = netdev_priv(dev); spin_lock(&sl->lock); if (!netif_running(dev)) { spin_unlock(&sl->lock); printk(KERN_WARNING "%s: xmit call when iface is down\n", dev->name); dev_kfree_skb(skb); return NETDEV_TX_OK; } if (sl->tty == NULL) { spin_unlock(&sl->lock); dev_kfree_skb(skb); return NETDEV_TX_OK; } sl_lock(sl); dev->stats.tx_bytes += skb->len; sl_encaps(sl, skb->data, skb->len); spin_unlock(&sl->lock); dev_kfree_skb(skb); return NETDEV_TX_OK; } /****************************************** * Routines looking at netdevice side. ******************************************/ /* Netdevice UP -> DOWN routine */ static int sl_close(struct net_device *dev) { struct slip *sl = netdev_priv(dev); spin_lock_bh(&sl->lock); if (sl->tty) /* TTY discipline is running. */ clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); netif_stop_queue(dev); sl->rcount = 0; sl->xleft = 0; spin_unlock_bh(&sl->lock); return 0; } /* Netdevice DOWN -> UP routine */ static int sl_open(struct net_device *dev) { struct slip *sl = netdev_priv(dev); if (sl->tty == NULL) return -ENODEV; sl->flags &= (1 << SLF_INUSE); netif_start_queue(dev); return 0; } /* Netdevice change MTU request */ static int sl_change_mtu(struct net_device *dev, int new_mtu) { struct slip *sl = netdev_priv(dev); return sl_realloc_bufs(sl, new_mtu); } /* Netdevice get statistics request */ static void sl_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats) { struct net_device_stats *devstats = &dev->stats; #ifdef SL_INCLUDE_CSLIP struct slip *sl = netdev_priv(dev); struct slcompress *comp = sl->slcomp; #endif stats->rx_packets = devstats->rx_packets; stats->tx_packets = devstats->tx_packets; stats->rx_bytes = devstats->rx_bytes; stats->tx_bytes = devstats->tx_bytes; stats->rx_dropped = devstats->rx_dropped; stats->tx_dropped = devstats->tx_dropped; stats->tx_errors = devstats->tx_errors; stats->rx_errors = devstats->rx_errors; stats->rx_over_errors = devstats->rx_over_errors; #ifdef SL_INCLUDE_CSLIP if (comp) { /* Generic compressed statistics */ stats->rx_compressed = comp->sls_i_compressed; stats->tx_compressed = comp->sls_o_compressed; /* Are we really still needs this? */ stats->rx_fifo_errors += comp->sls_i_compressed; stats->rx_dropped += comp->sls_i_tossed; stats->tx_fifo_errors += comp->sls_o_compressed; stats->collisions += comp->sls_o_misses; } #endif } /* Netdevice register callback */ static int sl_init(struct net_device *dev) { struct slip *sl = netdev_priv(dev); /* * Finish setting up the DEVICE info. */ dev->mtu = sl->mtu; dev->type = ARPHRD_SLIP + sl->mode; #ifdef SL_CHECK_TRANSMIT dev->watchdog_timeo = 20*HZ; #endif return 0; } static void sl_uninit(struct net_device *dev) { struct slip *sl = netdev_priv(dev); sl_free_bufs(sl); } /* Hook the destructor so we can free slip devices at the right point in time */ static void sl_free_netdev(struct net_device *dev) { int i = dev->base_addr; slip_devs[i] = NULL; } static const struct net_device_ops sl_netdev_ops = { .ndo_init = sl_init, .ndo_uninit = sl_uninit, .ndo_open = sl_open, .ndo_stop = sl_close, .ndo_start_xmit = sl_xmit, .ndo_get_stats64 = sl_get_stats64, .ndo_change_mtu = sl_change_mtu, .ndo_tx_timeout = sl_tx_timeout, #ifdef CONFIG_SLIP_SMART .ndo_do_ioctl = sl_ioctl, #endif }; static void sl_setup(struct net_device *dev) { dev->netdev_ops = &sl_netdev_ops; dev->needs_free_netdev = true; dev->priv_destructor = sl_free_netdev; dev->hard_header_len = 0; dev->addr_len = 0; dev->tx_queue_len = 10; /* MTU range: 68 - 65534 */ dev->min_mtu = 68; dev->max_mtu = 65534; /* New-style flags. */ dev->flags = IFF_NOARP|IFF_POINTOPOINT|IFF_MULTICAST; } /****************************************** Routines looking at TTY side. ******************************************/ /* * Handle the 'receiver data ready' interrupt. * This function is called by the 'tty_io' module in the kernel when * a block of SLIP data has been received, which can now be decapsulated * and sent on to some IP layer for further processing. This will not * be re-entered while running but other ldisc functions may be called * in parallel */ static void slip_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) { struct slip *sl = tty->disc_data; if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) return; /* Read the characters out of the buffer */ while (count--) { if (fp && *fp++) { if (!test_and_set_bit(SLF_ERROR, &sl->flags)) sl->dev->stats.rx_errors++; cp++; continue; } #ifdef CONFIG_SLIP_MODE_SLIP6 if (sl->mode & SL_MODE_SLIP6) slip_unesc6(sl, *cp++); else #endif slip_unesc(sl, *cp++); } } /************************************ * slip_open helper routines. ************************************/ /* Collect hanged up channels */ static void sl_sync(void) { int i; struct net_device *dev; struct slip *sl; for (i = 0; i < slip_maxdev; i++) { dev = slip_devs[i]; if (dev == NULL) break; sl = netdev_priv(dev); if (sl->tty || sl->leased) continue; if (dev->flags & IFF_UP) dev_close(dev); } } /* Find a free SLIP channel, and link in this `tty' line. */ static struct slip *sl_alloc(void) { int i; char name[IFNAMSIZ]; struct net_device *dev = NULL; struct slip *sl; for (i = 0; i < slip_maxdev; i++) { dev = slip_devs[i]; if (dev == NULL) break; } /* Sorry, too many, all slots in use */ if (i >= slip_maxdev) return NULL; sprintf(name, "sl%d", i); dev = alloc_netdev(sizeof(*sl), name, NET_NAME_UNKNOWN, sl_setup); if (!dev) return NULL; dev->base_addr = i; sl = netdev_priv(dev); /* Initialize channel control data */ sl->magic = SLIP_MAGIC; sl->dev = dev; spin_lock_init(&sl->lock); INIT_WORK(&sl->tx_work, slip_transmit); sl->mode = SL_MODE_DEFAULT; #ifdef CONFIG_SLIP_SMART /* initialize timer_list struct */ timer_setup(&sl->keepalive_timer, sl_keepalive, 0); timer_setup(&sl->outfill_timer, sl_outfill, 0); #endif slip_devs[i] = dev; return sl; } /* * Open the high-level part of the SLIP channel. * This function is called by the TTY module when the * SLIP line discipline is called for. Because we are * sure the tty line exists, we only have to link it to * a free SLIP channel... * * Called in process context serialized from other ldisc calls. */ static int slip_open(struct tty_struct *tty) { struct slip *sl; int err; if (!capable(CAP_NET_ADMIN)) return -EPERM; if (tty->ops->write == NULL) return -EOPNOTSUPP; /* RTnetlink lock is misused here to serialize concurrent opens of slip channels. There are better ways, but it is the simplest one. */ rtnl_lock(); /* Collect hanged up channels. */ sl_sync(); sl = tty->disc_data; err = -EEXIST; /* First make sure we're not already connected. */ if (sl && sl->magic == SLIP_MAGIC) goto err_exit; /* OK. Find a free SLIP channel to use. */ err = -ENFILE; sl = sl_alloc(); if (sl == NULL) goto err_exit; sl->tty = tty; tty->disc_data = sl; sl->pid = current->pid; if (!test_bit(SLF_INUSE, &sl->flags)) { /* Perform the low-level SLIP initialization. */ err = sl_alloc_bufs(sl, SL_MTU); if (err) goto err_free_chan; set_bit(SLF_INUSE, &sl->flags); err = register_netdevice(sl->dev); if (err) goto err_free_bufs; } #ifdef CONFIG_SLIP_SMART if (sl->keepalive) { sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; add_timer(&sl->keepalive_timer); } if (sl->outfill) { sl->outfill_timer.expires = jiffies + sl->outfill * HZ; add_timer(&sl->outfill_timer); } #endif /* Done. We have linked the TTY line to a channel. */ rtnl_unlock(); tty->receive_room = 65536; /* We don't flow control */ /* TTY layer expects 0 on success */ return 0; err_free_bufs: sl_free_bufs(sl); err_free_chan: sl->tty = NULL; tty->disc_data = NULL; clear_bit(SLF_INUSE, &sl->flags); sl_free_netdev(sl->dev); free_netdev(sl->dev); err_exit: rtnl_unlock(); /* Count references from TTY module */ return err; } /* * Close down a SLIP channel. * This means flushing out any pending queues, and then returning. This * call is serialized against other ldisc functions. * * We also use this method fo a hangup event */ static void slip_close(struct tty_struct *tty) { struct slip *sl = tty->disc_data; /* First make sure we're connected. */ if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty) return; spin_lock_bh(&sl->lock); rcu_assign_pointer(tty->disc_data, NULL); sl->tty = NULL; spin_unlock_bh(&sl->lock); synchronize_rcu(); flush_work(&sl->tx_work); /* VSV = very important to remove timers */ #ifdef CONFIG_SLIP_SMART del_timer_sync(&sl->keepalive_timer); del_timer_sync(&sl->outfill_timer); #endif /* Flush network side */ unregister_netdev(sl->dev); /* This will complete via sl_free_netdev */ } static int slip_hangup(struct tty_struct *tty) { slip_close(tty); return 0; } /************************************************************************ * STANDARD SLIP ENCAPSULATION * ************************************************************************/ static int slip_esc(unsigned char *s, unsigned char *d, int len) { unsigned char *ptr = d; unsigned char c; /* * Send an initial END character to flush out any * data that may have accumulated in the receiver * due to line noise. */ *ptr++ = END; /* * For each byte in the packet, send the appropriate * character sequence, according to the SLIP protocol. */ while (len-- > 0) { switch (c = *s++) { case END: *ptr++ = ESC; *ptr++ = ESC_END; break; case ESC: *ptr++ = ESC; *ptr++ = ESC_ESC; break; default: *ptr++ = c; break; } } *ptr++ = END; return ptr - d; } static void slip_unesc(struct slip *sl, unsigned char s) { switch (s) { case END: #ifdef CONFIG_SLIP_SMART /* drop keeptest bit = VSV */ if (test_bit(SLF_KEEPTEST, &sl->flags)) clear_bit(SLF_KEEPTEST, &sl->flags); #endif if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2)) sl_bump(sl); clear_bit(SLF_ESCAPE, &sl->flags); sl->rcount = 0; return; case ESC: set_bit(SLF_ESCAPE, &sl->flags); return; case ESC_ESC: if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) s = ESC; break; case ESC_END: if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) s = END; break; } if (!test_bit(SLF_ERROR, &sl->flags)) { if (sl->rcount < sl->buffsize) { sl->rbuff[sl->rcount++] = s; return; } sl->dev->stats.rx_over_errors++; set_bit(SLF_ERROR, &sl->flags); } } #ifdef CONFIG_SLIP_MODE_SLIP6 /************************************************************************ * 6 BIT SLIP ENCAPSULATION * ************************************************************************/ static int slip_esc6(unsigned char *s, unsigned char *d, int len) { unsigned char *ptr = d; unsigned char c; int i; unsigned short v = 0; short bits = 0; /* * Send an initial END character to flush out any * data that may have accumulated in the receiver * due to line noise. */ *ptr++ = 0x70; /* * Encode the packet into printable ascii characters */ for (i = 0; i < len; ++i) { v = (v << 8) | s[i]; bits += 8; while (bits >= 6) { bits -= 6; c = 0x30 + ((v >> bits) & 0x3F); *ptr++ = c; } } if (bits) { c = 0x30 + ((v << (6 - bits)) & 0x3F); *ptr++ = c; } *ptr++ = 0x70; return ptr - d; } static void slip_unesc6(struct slip *sl, unsigned char s) { unsigned char c; if (s == 0x70) { #ifdef CONFIG_SLIP_SMART /* drop keeptest bit = VSV */ if (test_bit(SLF_KEEPTEST, &sl->flags)) clear_bit(SLF_KEEPTEST, &sl->flags); #endif if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && (sl->rcount > 2)) sl_bump(sl); sl->rcount = 0; sl->xbits = 0; sl->xdata = 0; } else if (s >= 0x30 && s < 0x70) { sl->xdata = (sl->xdata << 6) | ((s - 0x30) & 0x3F); sl->xbits += 6; if (sl->xbits >= 8) { sl->xbits -= 8; c = (unsigned char)(sl->xdata >> sl->xbits); if (!test_bit(SLF_ERROR, &sl->flags)) { if (sl->rcount < sl->buffsize) { sl->rbuff[sl->rcount++] = c; return; } sl->dev->stats.rx_over_errors++; set_bit(SLF_ERROR, &sl->flags); } } } } #endif /* CONFIG_SLIP_MODE_SLIP6 */ /* Perform I/O control on an active SLIP channel. */ static int slip_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg) { struct slip *sl = tty->disc_data; unsigned int tmp; int __user *p = (int __user *)arg; /* First make sure we're connected. */ if (!sl || sl->magic != SLIP_MAGIC) return -EINVAL; switch (cmd) { case SIOCGIFNAME: tmp = strlen(sl->dev->name) + 1; if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) return -EFAULT; return 0; case SIOCGIFENCAP: if (put_user(sl->mode, p)) return -EFAULT; return 0; case SIOCSIFENCAP: if (get_user(tmp, p)) return -EFAULT; #ifndef SL_INCLUDE_CSLIP if (tmp & (SL_MODE_CSLIP|SL_MODE_ADAPTIVE)) return -EINVAL; #else if ((tmp & (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) == (SL_MODE_ADAPTIVE | SL_MODE_CSLIP)) /* return -EINVAL; */ tmp &= ~SL_MODE_ADAPTIVE; #endif #ifndef CONFIG_SLIP_MODE_SLIP6 if (tmp & SL_MODE_SLIP6) return -EINVAL; #endif sl->mode = tmp; sl->dev->type = ARPHRD_SLIP + sl->mode; return 0; case SIOCSIFHWADDR: return -EINVAL; #ifdef CONFIG_SLIP_SMART /* VSV changes start here */ case SIOCSKEEPALIVE: if (get_user(tmp, p)) return -EFAULT; if (tmp > 255) /* max for unchar */ return -EINVAL; spin_lock_bh(&sl->lock); if (!sl->tty) { spin_unlock_bh(&sl->lock); return -ENODEV; } sl->keepalive = (u8)tmp; if (sl->keepalive != 0) { mod_timer(&sl->keepalive_timer, jiffies + sl->keepalive * HZ); set_bit(SLF_KEEPTEST, &sl->flags); } else del_timer(&sl->keepalive_timer); spin_unlock_bh(&sl->lock); return 0; case SIOCGKEEPALIVE: if (put_user(sl->keepalive, p)) return -EFAULT; return 0; case SIOCSOUTFILL: if (get_user(tmp, p)) return -EFAULT; if (tmp > 255) /* max for unchar */ return -EINVAL; spin_lock_bh(&sl->lock); if (!sl->tty) { spin_unlock_bh(&sl->lock); return -ENODEV; } sl->outfill = (u8)tmp; if (sl->outfill != 0) { mod_timer(&sl->outfill_timer, jiffies + sl->outfill * HZ); set_bit(SLF_OUTWAIT, &sl->flags); } else del_timer(&sl->outfill_timer); spin_unlock_bh(&sl->lock); return 0; case SIOCGOUTFILL: if (put_user(sl->outfill, p)) return -EFAULT; return 0; /* VSV changes end */ #endif default: return tty_mode_ioctl(tty, file, cmd, arg); } } /* VSV changes start here */ #ifdef CONFIG_SLIP_SMART /* function do_ioctl called from net/core/dev.c to allow get/set outfill/keepalive parameter by ifconfig */ static int sl_ioctl(struct net_device *dev, struct ifreq *rq, int cmd) { struct slip *sl = netdev_priv(dev); unsigned long *p = (unsigned long *)&rq->ifr_ifru; if (sl == NULL) /* Allocation failed ?? */ return -ENODEV; spin_lock_bh(&sl->lock); if (!sl->tty) { spin_unlock_bh(&sl->lock); return -ENODEV; } switch (cmd) { case SIOCSKEEPALIVE: /* max for unchar */ if ((unsigned)*p > 255) { spin_unlock_bh(&sl->lock); return -EINVAL; } sl->keepalive = (u8)*p; if (sl->keepalive != 0) { sl->keepalive_timer.expires = jiffies + sl->keepalive * HZ; mod_timer(&sl->keepalive_timer, jiffies + sl->keepalive * HZ); set_bit(SLF_KEEPTEST, &sl->flags); } else del_timer(&sl->keepalive_timer); break; case SIOCGKEEPALIVE: *p = sl->keepalive; break; case SIOCSOUTFILL: if ((unsigned)*p > 255) { /* max for unchar */ spin_unlock_bh(&sl->lock); return -EINVAL; } sl->outfill = (u8)*p; if (sl->outfill != 0) { mod_timer(&sl->outfill_timer, jiffies + sl->outfill * HZ); set_bit(SLF_OUTWAIT, &sl->flags); } else del_timer(&sl->outfill_timer); break; case SIOCGOUTFILL: *p = sl->outfill; break; case SIOCSLEASE: /* Resolve race condition, when ioctl'ing hanged up and opened by another process device. */ if (sl->tty != current->signal->tty && sl->pid != current->pid) { spin_unlock_bh(&sl->lock); return -EPERM; } sl->leased = 0; if (*p) sl->leased = 1; break; case SIOCGLEASE: *p = sl->leased; } spin_unlock_bh(&sl->lock); return 0; } #endif /* VSV changes end */ static struct tty_ldisc_ops sl_ldisc = { .owner = THIS_MODULE, .magic = TTY_LDISC_MAGIC, .name = "slip", .open = slip_open, .close = slip_close, .hangup = slip_hangup, .ioctl = slip_ioctl, .receive_buf = slip_receive_buf, .write_wakeup = slip_write_wakeup, }; static int __init slip_init(void) { int status; if (slip_maxdev < 4) slip_maxdev = 4; /* Sanity */ printk(KERN_INFO "SLIP: version %s (dynamic channels, max=%d)" #ifdef CONFIG_SLIP_MODE_SLIP6 " (6 bit encapsulation enabled)" #endif ".\n", SLIP_VERSION, slip_maxdev); #if defined(SL_INCLUDE_CSLIP) printk(KERN_INFO "CSLIP: code copyright 1989 Regents of the University of California.\n"); #endif #ifdef CONFIG_SLIP_SMART printk(KERN_INFO "SLIP linefill/keepalive option.\n"); #endif slip_devs = kcalloc(slip_maxdev, sizeof(struct net_device *), GFP_KERNEL); if (!slip_devs) return -ENOMEM; /* Fill in our line protocol discipline, and register it */ status = tty_register_ldisc(N_SLIP, &sl_ldisc); if (status != 0) { printk(KERN_ERR "SLIP: can't register line discipline (err = %d)\n", status); kfree(slip_devs); } return status; } static void __exit slip_exit(void) { int i; struct net_device *dev; struct slip *sl; unsigned long timeout = jiffies + HZ; int busy = 0; if (slip_devs == NULL) return; /* First of all: check for active disciplines and hangup them. */ do { if (busy) msleep_interruptible(100); busy = 0; for (i = 0; i < slip_maxdev; i++) { dev = slip_devs[i]; if (!dev) continue; sl = netdev_priv(dev); spin_lock_bh(&sl->lock); if (sl->tty) { busy++; tty_hangup(sl->tty); } spin_unlock_bh(&sl->lock); } } while (busy && time_before(jiffies, timeout)); /* FIXME: hangup is async so we should wait when doing this second phase */ for (i = 0; i < slip_maxdev; i++) { dev = slip_devs[i]; if (!dev) continue; slip_devs[i] = NULL; sl = netdev_priv(dev); if (sl->tty) { printk(KERN_ERR "%s: tty discipline still running\n", dev->name); } unregister_netdev(dev); } kfree(slip_devs); slip_devs = NULL; i = tty_unregister_ldisc(N_SLIP); if (i != 0) printk(KERN_ERR "SLIP: can't unregister line discipline (err = %d)\n", i); } module_init(slip_init); module_exit(slip_exit); #ifdef CONFIG_SLIP_SMART /* * This is start of the code for multislip style line checking * added by Stanislav Voronyi. All changes before marked VSV */ static void sl_outfill(struct timer_list *t) { struct slip *sl = from_timer(sl, t, outfill_timer); spin_lock(&sl->lock); if (sl->tty == NULL) goto out; if (sl->outfill) { if (test_bit(SLF_OUTWAIT, &sl->flags)) { /* no packets were transmitted, do outfill */ #ifdef CONFIG_SLIP_MODE_SLIP6 unsigned char s = (sl->mode & SL_MODE_SLIP6)?0x70:END; #else unsigned char s = END; #endif /* put END into tty queue. Is it right ??? */ if (!netif_queue_stopped(sl->dev)) { /* if device busy no outfill */ sl->tty->ops->write(sl->tty, &s, 1); } } else set_bit(SLF_OUTWAIT, &sl->flags); mod_timer(&sl->outfill_timer, jiffies+sl->outfill*HZ); } out: spin_unlock(&sl->lock); } static void sl_keepalive(struct timer_list *t) { struct slip *sl = from_timer(sl, t, keepalive_timer); spin_lock(&sl->lock); if (sl->tty == NULL) goto out; if (sl->keepalive) { if (test_bit(SLF_KEEPTEST, &sl->flags)) { /* keepalive still high :(, we must hangup */ if (sl->outfill) /* outfill timer must be deleted too */ (void)del_timer(&sl->outfill_timer); printk(KERN_DEBUG "%s: no packets received during keepalive timeout, hangup.\n", sl->dev->name); /* this must hangup tty & close slip */ tty_hangup(sl->tty); /* I think we need not something else */ goto out; } else set_bit(SLF_KEEPTEST, &sl->flags); mod_timer(&sl->keepalive_timer, jiffies+sl->keepalive*HZ); } out: spin_unlock(&sl->lock); } #endif MODULE_LICENSE("GPL"); MODULE_ALIAS_LDISC(N_SLIP);