diff options
Diffstat (limited to 'kernel/drivers/net/wan/x25_asy.c')
| -rw-r--r-- | kernel/drivers/net/wan/x25_asy.c | 827 |
1 files changed, 827 insertions, 0 deletions
diff --git a/kernel/drivers/net/wan/x25_asy.c b/kernel/drivers/net/wan/x25_asy.c new file mode 100644 index 000000000..5c47b011a --- /dev/null +++ b/kernel/drivers/net/wan/x25_asy.c @@ -0,0 +1,827 @@ +/* + * Things to sort out: + * + * o tbusy handling + * o allow users to set the parameters + * o sync/async switching ? + * + * Note: This does _not_ implement CCITT X.25 asynchronous framing + * recommendations. Its primarily for testing purposes. If you wanted + * to do CCITT then in theory all you need is to nick the HDLC async + * checksum routines from ppp.c + * Changes: + * + * 2000-10-29 Henner Eisen lapb_data_indication() return status. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> + +#include <linux/uaccess.h> +#include <linux/bitops.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/if_arp.h> +#include <linux/lapb.h> +#include <linux/init.h> +#include <linux/rtnetlink.h> +#include <linux/compat.h> +#include <linux/slab.h> +#include <net/x25device.h> +#include "x25_asy.h" + +static struct net_device **x25_asy_devs; +static int x25_asy_maxdev = SL_NRUNIT; + +module_param(x25_asy_maxdev, int, 0); +MODULE_LICENSE("GPL"); + +static int x25_asy_esc(unsigned char *p, unsigned char *d, int len); +static void x25_asy_unesc(struct x25_asy *sl, unsigned char c); +static void x25_asy_setup(struct net_device *dev); + +/* Find a free X.25 channel, and link in this `tty' line. */ +static struct x25_asy *x25_asy_alloc(void) +{ + struct net_device *dev = NULL; + struct x25_asy *sl; + int i; + + if (x25_asy_devs == NULL) + return NULL; /* Master array missing ! */ + + for (i = 0; i < x25_asy_maxdev; i++) { + dev = x25_asy_devs[i]; + + /* Not allocated ? */ + if (dev == NULL) + break; + + sl = netdev_priv(dev); + /* Not in use ? */ + if (!test_and_set_bit(SLF_INUSE, &sl->flags)) + return sl; + } + + + /* Sorry, too many, all slots in use */ + if (i >= x25_asy_maxdev) + return NULL; + + /* If no channels are available, allocate one */ + if (!dev) { + char name[IFNAMSIZ]; + sprintf(name, "x25asy%d", i); + + dev = alloc_netdev(sizeof(struct x25_asy), name, + NET_NAME_UNKNOWN, x25_asy_setup); + if (!dev) + return NULL; + + /* Initialize channel control data */ + sl = netdev_priv(dev); + dev->base_addr = i; + + /* register device so that it can be ifconfig'ed */ + if (register_netdev(dev) == 0) { + /* (Re-)Set the INUSE bit. Very Important! */ + set_bit(SLF_INUSE, &sl->flags); + x25_asy_devs[i] = dev; + return sl; + } else { + pr_warn("%s(): register_netdev() failure\n", __func__); + free_netdev(dev); + } + } + return NULL; +} + + +/* Free an X.25 channel. */ +static void x25_asy_free(struct x25_asy *sl) +{ + /* Free all X.25 frame buffers. */ + kfree(sl->rbuff); + sl->rbuff = NULL; + kfree(sl->xbuff); + sl->xbuff = NULL; + + if (!test_and_clear_bit(SLF_INUSE, &sl->flags)) + netdev_err(sl->dev, "x25_asy_free for already free unit\n"); +} + +static int x25_asy_change_mtu(struct net_device *dev, int newmtu) +{ + struct x25_asy *sl = netdev_priv(dev); + unsigned char *xbuff, *rbuff; + int len; + + if (newmtu > 65534) + return -EINVAL; + + len = 2 * newmtu; + xbuff = kmalloc(len + 4, GFP_ATOMIC); + rbuff = kmalloc(len + 4, GFP_ATOMIC); + + if (xbuff == NULL || rbuff == NULL) { + kfree(xbuff); + kfree(rbuff); + return -ENOMEM; + } + + spin_lock_bh(&sl->lock); + xbuff = xchg(&sl->xbuff, xbuff); + 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; + + rbuff = xchg(&sl->rbuff, rbuff); + 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); + } + } + + dev->mtu = newmtu; + sl->buffsize = len; + + spin_unlock_bh(&sl->lock); + + kfree(xbuff); + kfree(rbuff); + return 0; +} + + +/* Set the "sending" flag. This must be atomic, hence the ASM. */ + +static inline void x25_asy_lock(struct x25_asy *sl) +{ + netif_stop_queue(sl->dev); +} + + +/* Clear the "sending" flag. This must be atomic, hence the ASM. */ + +static inline void x25_asy_unlock(struct x25_asy *sl) +{ + netif_wake_queue(sl->dev); +} + +/* Send one completely decapsulated IP datagram to the IP layer. */ + +static void x25_asy_bump(struct x25_asy *sl) +{ + struct net_device *dev = sl->dev; + struct sk_buff *skb; + int count; + int err; + + count = sl->rcount; + dev->stats.rx_bytes += count; + + skb = dev_alloc_skb(count+1); + if (skb == NULL) { + netdev_warn(sl->dev, "memory squeeze, dropping packet\n"); + dev->stats.rx_dropped++; + return; + } + skb_push(skb, 1); /* LAPB internal control */ + memcpy(skb_put(skb, count), sl->rbuff, count); + skb->protocol = x25_type_trans(skb, sl->dev); + err = lapb_data_received(skb->dev, skb); + if (err != LAPB_OK) { + kfree_skb(skb); + printk(KERN_DEBUG "x25_asy: data received err - %d\n", err); + } else { + netif_rx(skb); + dev->stats.rx_packets++; + } +} + +/* Encapsulate one IP datagram and stuff into a TTY queue. */ +static void x25_asy_encaps(struct x25_asy *sl, unsigned char *icp, int len) +{ + unsigned char *p; + int actual, count, mtu = sl->dev->mtu; + + if (len > mtu) { + /* Sigh, shouldn't occur BUT ... */ + len = mtu; + printk(KERN_DEBUG "%s: truncating oversized transmit packet!\n", + sl->dev->name); + sl->dev->stats.tx_dropped++; + x25_asy_unlock(sl); + return; + } + + p = icp; + count = x25_asy_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 driver.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); + sl->xleft = count - actual; + sl->xhead = sl->xbuff + actual; + /* VSV */ + clear_bit(SLF_OUTWAIT, &sl->flags); /* reset outfill flag */ +} + +/* + * Called by the driver when there's room for more data. If we have + * more packets to send, we send them here. + */ +static void x25_asy_write_wakeup(struct tty_struct *tty) +{ + int actual; + struct x25_asy *sl = tty->disc_data; + + /* First make sure we're connected. */ + if (!sl || sl->magic != X25_ASY_MAGIC || !netif_running(sl->dev)) + 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, &tty->flags); + x25_asy_unlock(sl); + return; + } + + actual = tty->ops->write(tty, sl->xhead, sl->xleft); + sl->xleft -= actual; + sl->xhead += actual; +} + +static void x25_asy_timeout(struct net_device *dev) +{ + struct x25_asy *sl = netdev_priv(dev); + + spin_lock(&sl->lock); + if (netif_queue_stopped(dev)) { + /* May be we must check transmitter timeout here ? + * 14 Oct 1994 Dmitry Gorodchanin. + */ + netdev_warn(dev, "transmit timed out, %s?\n", + (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); + x25_asy_unlock(sl); + } + spin_unlock(&sl->lock); +} + +/* Encapsulate an IP datagram and kick it into a TTY queue. */ + +static netdev_tx_t x25_asy_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct x25_asy *sl = netdev_priv(dev); + int err; + + if (!netif_running(sl->dev)) { + netdev_err(dev, "xmit call when iface is down\n"); + kfree_skb(skb); + return NETDEV_TX_OK; + } + + switch (skb->data[0]) { + case X25_IFACE_DATA: + break; + case X25_IFACE_CONNECT: /* Connection request .. do nothing */ + err = lapb_connect_request(dev); + if (err != LAPB_OK) + netdev_err(dev, "lapb_connect_request error: %d\n", + err); + kfree_skb(skb); + return NETDEV_TX_OK; + case X25_IFACE_DISCONNECT: /* do nothing - hang up ?? */ + err = lapb_disconnect_request(dev); + if (err != LAPB_OK) + netdev_err(dev, "lapb_disconnect_request error: %d\n", + err); + default: + kfree_skb(skb); + return NETDEV_TX_OK; + } + skb_pull(skb, 1); /* Remove control byte */ + /* + * If we are busy already- too bad. We ought to be able + * to queue things at this point, to allow for a little + * frame buffer. Oh well... + * ----------------------------------------------------- + * I hate queues in X.25 driver. May be it's efficient, + * but for me latency is more important. ;) + * So, no queues ! + * 14 Oct 1994 Dmitry Gorodchanin. + */ + + err = lapb_data_request(dev, skb); + if (err != LAPB_OK) { + netdev_err(dev, "lapb_data_request error: %d\n", err); + kfree_skb(skb); + return NETDEV_TX_OK; + } + return NETDEV_TX_OK; +} + + +/* + * LAPB interface boilerplate + */ + +/* + * Called when I frame data arrives. We did the work above - throw it + * at the net layer. + */ + +static int x25_asy_data_indication(struct net_device *dev, struct sk_buff *skb) +{ + return netif_rx(skb); +} + +/* + * Data has emerged from the LAPB protocol machine. We don't handle + * busy cases too well. Its tricky to see how to do this nicely - + * perhaps lapb should allow us to bounce this ? + */ + +static void x25_asy_data_transmit(struct net_device *dev, struct sk_buff *skb) +{ + struct x25_asy *sl = netdev_priv(dev); + + spin_lock(&sl->lock); + if (netif_queue_stopped(sl->dev) || sl->tty == NULL) { + spin_unlock(&sl->lock); + netdev_err(dev, "tbusy drop\n"); + kfree_skb(skb); + return; + } + /* We were not busy, so we are now... :-) */ + if (skb != NULL) { + x25_asy_lock(sl); + dev->stats.tx_bytes += skb->len; + x25_asy_encaps(sl, skb->data, skb->len); + dev_kfree_skb(skb); + } + spin_unlock(&sl->lock); +} + +/* + * LAPB connection establish/down information. + */ + +static void x25_asy_connected(struct net_device *dev, int reason) +{ + struct x25_asy *sl = netdev_priv(dev); + struct sk_buff *skb; + unsigned char *ptr; + + skb = dev_alloc_skb(1); + if (skb == NULL) { + netdev_err(dev, "out of memory\n"); + return; + } + + ptr = skb_put(skb, 1); + *ptr = X25_IFACE_CONNECT; + + skb->protocol = x25_type_trans(skb, sl->dev); + netif_rx(skb); +} + +static void x25_asy_disconnected(struct net_device *dev, int reason) +{ + struct x25_asy *sl = netdev_priv(dev); + struct sk_buff *skb; + unsigned char *ptr; + + skb = dev_alloc_skb(1); + if (skb == NULL) { + netdev_err(dev, "out of memory\n"); + return; + } + + ptr = skb_put(skb, 1); + *ptr = X25_IFACE_DISCONNECT; + + skb->protocol = x25_type_trans(skb, sl->dev); + netif_rx(skb); +} + +static const struct lapb_register_struct x25_asy_callbacks = { + .connect_confirmation = x25_asy_connected, + .connect_indication = x25_asy_connected, + .disconnect_confirmation = x25_asy_disconnected, + .disconnect_indication = x25_asy_disconnected, + .data_indication = x25_asy_data_indication, + .data_transmit = x25_asy_data_transmit, +}; + + +/* Open the low-level part of the X.25 channel. Easy! */ +static int x25_asy_open(struct net_device *dev) +{ + struct x25_asy *sl = netdev_priv(dev); + unsigned long len; + int err; + + if (sl->tty == NULL) + return -ENODEV; + + /* + * Allocate the X.25 frame buffers: + * + * rbuff Receive buffer. + * xbuff Transmit buffer. + */ + + len = dev->mtu * 2; + + sl->rbuff = kmalloc(len + 4, GFP_KERNEL); + if (sl->rbuff == NULL) + goto norbuff; + sl->xbuff = kmalloc(len + 4, GFP_KERNEL); + if (sl->xbuff == NULL) + goto noxbuff; + + sl->buffsize = len; + sl->rcount = 0; + sl->xleft = 0; + sl->flags &= (1 << SLF_INUSE); /* Clear ESCAPE & ERROR flags */ + + netif_start_queue(dev); + + /* + * Now attach LAPB + */ + err = lapb_register(dev, &x25_asy_callbacks); + if (err == LAPB_OK) + return 0; + + /* Cleanup */ + kfree(sl->xbuff); +noxbuff: + kfree(sl->rbuff); +norbuff: + return -ENOMEM; +} + + +/* Close the low-level part of the X.25 channel. Easy! */ +static int x25_asy_close(struct net_device *dev) +{ + struct x25_asy *sl = netdev_priv(dev); + + spin_lock(&sl->lock); + if (sl->tty) + clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); + + netif_stop_queue(dev); + sl->rcount = 0; + sl->xleft = 0; + spin_unlock(&sl->lock); + return 0; +} + +/* + * Handle the 'receiver data ready' interrupt. + * This function is called by the 'tty_io' module in the kernel when + * a block of X.25 data has been received, which can now be decapsulated + * and sent on to some IP layer for further processing. + */ + +static void x25_asy_receive_buf(struct tty_struct *tty, + const unsigned char *cp, char *fp, int count) +{ + struct x25_asy *sl = tty->disc_data; + + if (!sl || sl->magic != X25_ASY_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; + } + x25_asy_unesc(sl, *cp++); + } +} + +/* + * Open the high-level part of the X.25 channel. + * This function is called by the TTY module when the + * X.25 line discipline is called for. Because we are + * sure the tty line exists, we only have to link it to + * a free X.25 channel... + */ + +static int x25_asy_open_tty(struct tty_struct *tty) +{ + struct x25_asy *sl = tty->disc_data; + int err; + + if (tty->ops->write == NULL) + return -EOPNOTSUPP; + + /* First make sure we're not already connected. */ + if (sl && sl->magic == X25_ASY_MAGIC) + return -EEXIST; + + /* OK. Find a free X.25 channel to use. */ + sl = x25_asy_alloc(); + if (sl == NULL) + return -ENFILE; + + sl->tty = tty; + tty->disc_data = sl; + tty->receive_room = 65536; + tty_driver_flush_buffer(tty); + tty_ldisc_flush(tty); + + /* Restore default settings */ + sl->dev->type = ARPHRD_X25; + + /* Perform the low-level X.25 async init */ + err = x25_asy_open(sl->dev); + if (err) + return err; + /* Done. We have linked the TTY line to a channel. */ + return 0; +} + + +/* + * Close down an X.25 channel. + * This means flushing out any pending queues, and then restoring the + * TTY line discipline to what it was before it got hooked to X.25 + * (which usually is TTY again). + */ +static void x25_asy_close_tty(struct tty_struct *tty) +{ + struct x25_asy *sl = tty->disc_data; + int err; + + /* First make sure we're connected. */ + if (!sl || sl->magic != X25_ASY_MAGIC) + return; + + rtnl_lock(); + if (sl->dev->flags & IFF_UP) + dev_close(sl->dev); + rtnl_unlock(); + + err = lapb_unregister(sl->dev); + if (err != LAPB_OK) + pr_err("x25_asy_close: lapb_unregister error: %d\n", + err); + + tty->disc_data = NULL; + sl->tty = NULL; + x25_asy_free(sl); +} + + /************************************************************************ + * STANDARD X.25 ENCAPSULATION * + ************************************************************************/ + +static int x25_asy_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++ = X25_END; /* Send 10111110 bit seq */ + + /* + * For each byte in the packet, send the appropriate + * character sequence, according to the X.25 protocol. + */ + + while (len-- > 0) { + switch (c = *s++) { + case X25_END: + *ptr++ = X25_ESC; + *ptr++ = X25_ESCAPE(X25_END); + break; + case X25_ESC: + *ptr++ = X25_ESC; + *ptr++ = X25_ESCAPE(X25_ESC); + break; + default: + *ptr++ = c; + break; + } + } + *ptr++ = X25_END; + return ptr - d; +} + +static void x25_asy_unesc(struct x25_asy *sl, unsigned char s) +{ + + switch (s) { + case X25_END: + if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && + sl->rcount > 2) + x25_asy_bump(sl); + clear_bit(SLF_ESCAPE, &sl->flags); + sl->rcount = 0; + return; + case X25_ESC: + set_bit(SLF_ESCAPE, &sl->flags); + return; + case X25_ESCAPE(X25_ESC): + case X25_ESCAPE(X25_END): + if (test_and_clear_bit(SLF_ESCAPE, &sl->flags)) + s = X25_UNESCAPE(s); + 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); + } +} + + +/* Perform I/O control on an active X.25 channel. */ +static int x25_asy_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct x25_asy *sl = tty->disc_data; + + /* First make sure we're connected. */ + if (!sl || sl->magic != X25_ASY_MAGIC) + return -EINVAL; + + switch (cmd) { + case SIOCGIFNAME: + if (copy_to_user((void __user *)arg, sl->dev->name, + strlen(sl->dev->name) + 1)) + return -EFAULT; + return 0; + case SIOCSIFHWADDR: + return -EINVAL; + default: + return tty_mode_ioctl(tty, file, cmd, arg); + } +} + +#ifdef CONFIG_COMPAT +static long x25_asy_compat_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case SIOCGIFNAME: + case SIOCSIFHWADDR: + return x25_asy_ioctl(tty, file, cmd, + (unsigned long)compat_ptr(arg)); + } + + return -ENOIOCTLCMD; +} +#endif + +static int x25_asy_open_dev(struct net_device *dev) +{ + struct x25_asy *sl = netdev_priv(dev); + if (sl->tty == NULL) + return -ENODEV; + return 0; +} + +static const struct net_device_ops x25_asy_netdev_ops = { + .ndo_open = x25_asy_open_dev, + .ndo_stop = x25_asy_close, + .ndo_start_xmit = x25_asy_xmit, + .ndo_tx_timeout = x25_asy_timeout, + .ndo_change_mtu = x25_asy_change_mtu, +}; + +/* Initialise the X.25 driver. Called by the device init code */ +static void x25_asy_setup(struct net_device *dev) +{ + struct x25_asy *sl = netdev_priv(dev); + + sl->magic = X25_ASY_MAGIC; + sl->dev = dev; + spin_lock_init(&sl->lock); + set_bit(SLF_INUSE, &sl->flags); + + /* + * Finish setting up the DEVICE info. + */ + + dev->mtu = SL_MTU; + dev->netdev_ops = &x25_asy_netdev_ops; + dev->watchdog_timeo = HZ*20; + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->type = ARPHRD_X25; + dev->tx_queue_len = 10; + + /* New-style flags. */ + dev->flags = IFF_NOARP; +} + +static struct tty_ldisc_ops x25_ldisc = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = "X.25", + .open = x25_asy_open_tty, + .close = x25_asy_close_tty, + .ioctl = x25_asy_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = x25_asy_compat_ioctl, +#endif + .receive_buf = x25_asy_receive_buf, + .write_wakeup = x25_asy_write_wakeup, +}; + +static int __init init_x25_asy(void) +{ + if (x25_asy_maxdev < 4) + x25_asy_maxdev = 4; /* Sanity */ + + pr_info("X.25 async: version 0.00 ALPHA (dynamic channels, max=%d)\n", + x25_asy_maxdev); + + x25_asy_devs = kcalloc(x25_asy_maxdev, sizeof(struct net_device *), + GFP_KERNEL); + if (!x25_asy_devs) + return -ENOMEM; + + return tty_register_ldisc(N_X25, &x25_ldisc); +} + + +static void __exit exit_x25_asy(void) +{ + struct net_device *dev; + int i; + + for (i = 0; i < x25_asy_maxdev; i++) { + dev = x25_asy_devs[i]; + if (dev) { + struct x25_asy *sl = netdev_priv(dev); + + spin_lock_bh(&sl->lock); + if (sl->tty) + tty_hangup(sl->tty); + + spin_unlock_bh(&sl->lock); + /* + * VSV = if dev->start==0, then device + * unregistered while close proc. + */ + unregister_netdev(dev); + free_netdev(dev); + } + } + + kfree(x25_asy_devs); + tty_unregister_ldisc(N_X25); +} + +module_init(init_x25_asy); +module_exit(exit_x25_asy); |