| // 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, <loz@holmes.demon.co.uk> |
| * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> |
| * |
| * 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 <jfree@caldera.com> |
| * 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 <linux/module.h> |
| #include <linux/moduleparam.h> |
| |
| #include <linux/uaccess.h> |
| #include <linux/bitops.h> |
| #include <linux/sched/signal.h> |
| #include <linux/string.h> |
| #include <linux/mm.h> |
| #include <linux/interrupt.h> |
| #include <linux/in.h> |
| #include <linux/tty.h> |
| #include <linux/errno.h> |
| #include <linux/netdevice.h> |
| #include <linux/etherdevice.h> |
| #include <linux/skbuff.h> |
| #include <linux/rtnetlink.h> |
| #include <linux/if_arp.h> |
| #include <linux/if_slip.h> |
| #include <linux/delay.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <linux/workqueue.h> |
| #include "slip.h" |
| #ifdef CONFIG_INET |
| #include <linux/ip.h> |
| #include <linux/tcp.h> |
| #include <net/slhc_vj.h> |
| #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) |
| { |
| 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); |
| /* do not call free_netdev before rtnl_unlock */ |
| rtnl_unlock(); |
| free_netdev(sl->dev); |
| return err; |
| |
| 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); |