--- /dev/null
+/*
+ * 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 <asm/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/sched.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/compat.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(unsigned long sls);
+static void sl_outfill(unsigned long sls);
+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 (slcomp == NULL)
+ 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;
+ memcpy(skb_put(skb, count), 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
+ sl->dev->trans_start = jiffies;
+#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 = tty->disc_data;
+
+ schedule_work(&sl->tx_work);
+}
+
+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);
+
+ if (new_mtu < 68 || new_mtu > 65534)
+ return -EINVAL;
+
+ if (new_mtu != dev->mtu)
+ return sl_realloc_bufs(sl, new_mtu);
+ return 0;
+}
+
+/* Netdevice get statistics request */
+
+static struct rtnl_link_stats64 *
+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
+ return stats;
+}
+
+/* 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;
+ free_netdev(dev);
+ 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->destructor = sl_free_netdev;
+
+ dev->hard_header_len = 0;
+ dev->addr_len = 0;
+ dev->tx_queue_len = 10;
+
+ /* 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(dev_t line)
+{
+ 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 */
+ init_timer(&sl->keepalive_timer);
+ sl->keepalive_timer.data = (unsigned long)sl;
+ sl->keepalive_timer.function = sl_keepalive;
+ init_timer(&sl->outfill_timer);
+ sl->outfill_timer.data = (unsigned long)sl;
+ sl->outfill_timer.function = sl_outfill;
+#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(tty_devnum(tty));
+ 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);
+
+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);
+ tty->disc_data = NULL;
+ sl->tty = NULL;
+ spin_unlock_bh(&sl->lock);
+
+ 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);
+ }
+}
+
+#ifdef CONFIG_COMPAT
+static long slip_compat_ioctl(struct tty_struct *tty, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+ case SIOCGIFNAME:
+ case SIOCGIFENCAP:
+ case SIOCSIFENCAP:
+ case SIOCSIFHWADDR:
+ case SIOCSKEEPALIVE:
+ case SIOCGKEEPALIVE:
+ case SIOCSOUTFILL:
+ case SIOCGOUTFILL:
+ return slip_ioctl(tty, file, cmd,
+ (unsigned long)compat_ptr(arg));
+ }
+
+ return -ENOIOCTLCMD;
+}
+#endif
+
+/* 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,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = slip_compat_ioctl,
+#endif
+ .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 = kzalloc(sizeof(struct net_device *)*slip_maxdev,
+ 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);
+ /* Intentionally leak the control block. */
+ dev->destructor = NULL;
+ }
+
+ 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(unsigned long sls)
+{
+ struct slip *sl = (struct slip *)sls;
+
+ 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(unsigned long sls)
+{
+ struct slip *sl = (struct slip *)sls;
+
+ 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);
Code Review / kvmfornfv.git / blobdiff