diff options
Diffstat (limited to 'drivers/net/slip/slip.c')
| -rw-r--r-- | drivers/net/slip/slip.c | 1441 |
1 files changed, 1441 insertions, 0 deletions
diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c new file mode 100644 index 000000000..6865d3227 --- /dev/null +++ b/drivers/net/slip/slip.c @@ -0,0 +1,1441 @@ +// 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/compat.h> +#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_siocdevprivate(struct net_device *dev, struct ifreq *rq, void __user *data, 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(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) + schedule_work(&sl->tx_work); + 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) || !sl->tty) + 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_siocdevprivate = sl_siocdevprivate, +#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, + const 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 void slip_hangup(struct tty_struct *tty) +{ + slip_close(tty); +} + /************************************************************************ + * 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, 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, cmd, arg); + } +} + +/* VSV changes start here */ +#ifdef CONFIG_SLIP_SMART +/* function sl_siocdevprivate called from net/core/dev.c + to allow get/set outfill/keepalive parameter + by ifconfig */ + +static int sl_siocdevprivate(struct net_device *dev, struct ifreq *rq, + void __user *data, int cmd) +{ + struct slip *sl = netdev_priv(dev); + unsigned long *p = (unsigned long *)&rq->ifr_ifru; + + if (sl == NULL) /* Allocation failed ?? */ + return -ENODEV; + + if (in_compat_syscall()) + return -EOPNOTSUPP; + + 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, + .num = N_SLIP, + .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(&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; + + tty_unregister_ldisc(&sl_ldisc); +} + +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); |