/* * 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. */ #include <linux/module.h> #include <asm/system.h> #include <asm/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/x25.h> #include <linux/lapb.h> #include <linux/init.h> #include "x25_asy.h" #include <net/x25device.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 = dev->priv; /* 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, x25_asy_setup); if (!dev) return NULL; /* Initialize channel control data */ sl = dev->priv; 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 { printk("x25_asy_alloc() - register_netdev() failure.\n"); 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)) { printk("%s: x25_asy_free for already free unit.\n", sl->dev->name); } } static int x25_asy_change_mtu(struct net_device *dev, int newmtu) { struct x25_asy *sl = dev->priv; unsigned char *xbuff, *rbuff; int len = 2* newmtu; xbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC); rbuff = (unsigned char *) kmalloc (len + 4, GFP_ATOMIC); if (xbuff == NULL || rbuff == NULL) { printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n", dev->name); 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; sl->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; sl->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 sk_buff *skb; int count; int err; count = sl->rcount; sl->stats.rx_bytes+=count; skb = dev_alloc_skb(count+1); if (skb == NULL) { printk("%s: memory squeeze, dropping packet.\n", sl->dev->name); sl->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); if((err=lapb_data_received(skb->dev, skb))!=LAPB_OK) { kfree_skb(skb); printk(KERN_DEBUG "x25_asy: data received err - %d\n",err); } else { netif_rx(skb); sl->dev->last_rx = jiffies; sl->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 ("%s: truncating oversized transmit packet!\n", sl->dev->name); sl->stats.tx_dropped++; x25_asy_unlock(sl); return; } p = icp; count = x25_asy_esc(p, (unsigned char *) 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. */ sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP); actual = sl->tty->driver->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 = (struct x25_asy *) 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->stats.tx_packets++; tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP); x25_asy_unlock(sl); return; } actual = tty->driver->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 = (struct x25_asy*)(dev->priv); spin_lock(&sl->lock); if (netif_queue_stopped(dev)) { /* May be we must check transmitter timeout here ? * 14 Oct 1994 Dmitry Gorodchanin. */ printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name, (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ? "bad line quality" : "driver error"); sl->xleft = 0; sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP); x25_asy_unlock(sl); } spin_unlock(&sl->lock); } /* Encapsulate an IP datagram and kick it into a TTY queue. */ static int x25_asy_xmit(struct sk_buff *skb, struct net_device *dev) { struct x25_asy *sl = (struct x25_asy*)(dev->priv); int err; if (!netif_running(sl->dev)) { printk("%s: xmit call when iface is down\n", dev->name); kfree_skb(skb); return 0; } switch(skb->data[0]) { case 0x00:break; case 0x01: /* Connection request .. do nothing */ if((err=lapb_connect_request(dev))!=LAPB_OK) printk(KERN_ERR "x25_asy: lapb_connect_request error - %d\n", err); kfree_skb(skb); return 0; case 0x02: /* Disconnect request .. do nothing - hang up ?? */ if((err=lapb_disconnect_request(dev))!=LAPB_OK) printk(KERN_ERR "x25_asy: lapb_disconnect_request error - %d\n", err); default: kfree_skb(skb); return 0; } 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. */ if((err=lapb_data_request(dev,skb))!=LAPB_OK) { printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err); kfree_skb(skb); return 0; } return 0; } /* * 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) { skb->dev->last_rx = jiffies; 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=dev->priv; spin_lock(&sl->lock); if (netif_queue_stopped(sl->dev) || sl->tty == NULL) { spin_unlock(&sl->lock); printk(KERN_ERR "x25_asy: tbusy drop\n"); kfree_skb(skb); return; } /* We were not busy, so we are now... :-) */ if (skb != NULL) { x25_asy_lock(sl); sl->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 = dev->priv; struct sk_buff *skb; unsigned char *ptr; if ((skb = dev_alloc_skb(1)) == NULL) { printk(KERN_ERR "lapbeth: out of memory\n"); return; } ptr = skb_put(skb, 1); *ptr = 0x01; skb->protocol = x25_type_trans(skb, sl->dev); netif_rx(skb); sl->dev->last_rx = jiffies; } static void x25_asy_disconnected(struct net_device *dev, int reason) { struct x25_asy *sl = dev->priv; struct sk_buff *skb; unsigned char *ptr; if ((skb = dev_alloc_skb(1)) == NULL) { printk(KERN_ERR "x25_asy: out of memory\n"); return; } ptr = skb_put(skb, 1); *ptr = 0x02; skb->protocol = x25_type_trans(skb, sl->dev); netif_rx(skb); sl->dev->last_rx = jiffies; } static 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 = (struct x25_asy*)(dev->priv); 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 = (unsigned char *) kmalloc(len + 4, GFP_KERNEL); if (sl->rbuff == NULL) { goto norbuff; } sl->xbuff = (unsigned char *) 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 */ if((err=lapb_register(dev, &x25_asy_callbacks))==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 = (struct x25_asy*)(dev->priv); int err; spin_lock(&sl->lock); if (sl->tty) sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP); netif_stop_queue(dev); sl->rcount = 0; sl->xleft = 0; if((err=lapb_unregister(dev))!=LAPB_OK) printk(KERN_ERR "x25_asy_close: lapb_unregister error -%d\n",err); spin_unlock(&sl->lock); return 0; } static int x25_asy_receive_room(struct tty_struct *tty) { return 65536; /* We can handle an infinite amount of data. :-) */ } /* * 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 = (struct x25_asy *) 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->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 = (struct x25_asy *) tty->disc_data; int err; /* 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. */ if ((sl = x25_asy_alloc()) == NULL) { return -ENFILE; } sl->tty = tty; tty->disc_data = sl; if (tty->driver->flush_buffer) { tty->driver->flush_buffer(tty); } if (tty->ldisc.flush_buffer) { tty->ldisc.flush_buffer(tty); } /* Restore default settings */ sl->dev->type = ARPHRD_X25; /* Perform the low-level X.25 async init */ if ((err = x25_asy_open(sl->dev))) return err; /* Done. We have linked the TTY line to a channel. */ return sl->dev->base_addr; } /* * 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 = (struct x25_asy *) tty->disc_data; /* First make sure we're connected. */ if (!sl || sl->magic != X25_ASY_MAGIC) return; if (sl->dev->flags & IFF_UP) { (void) dev_close(sl->dev); } tty->disc_data = NULL; sl->tty = NULL; x25_asy_free(sl); } static struct net_device_stats *x25_asy_get_stats(struct net_device *dev) { struct x25_asy *sl = (struct x25_asy*)(dev->priv); return &sl->stats; } /************************************************************************ * STANDARD X.25 ENCAPSULATION * ************************************************************************/ 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->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 = (struct x25_asy *) 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; /* Allow stty to read, but not set, the serial port */ case TCGETS: case TCGETA: return n_tty_ioctl(tty, file, cmd, arg); default: return -ENOIOCTLCMD; } } static int x25_asy_open_dev(struct net_device *dev) { struct x25_asy *sl = (struct x25_asy*)(dev->priv); if(sl->tty==NULL) return -ENODEV; return 0; } /* Initialise the X.25 driver. Called by the device init code */ static void x25_asy_setup(struct net_device *dev) { struct x25_asy *sl = dev->priv; 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->hard_start_xmit = x25_asy_xmit; dev->tx_timeout = x25_asy_timeout; dev->watchdog_timeo = HZ*20; dev->open = x25_asy_open_dev; dev->stop = x25_asy_close; dev->get_stats = x25_asy_get_stats; dev->change_mtu = x25_asy_change_mtu; 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 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, .receive_buf = x25_asy_receive_buf, .receive_room = x25_asy_receive_room, .write_wakeup = x25_asy_write_wakeup, }; static int __init init_x25_asy(void) { if (x25_asy_maxdev < 4) x25_asy_maxdev = 4; /* Sanity */ printk(KERN_INFO "X.25 async: version 0.00 ALPHA " "(dynamic channels, max=%d).\n", x25_asy_maxdev ); x25_asy_devs = kmalloc(sizeof(struct net_device *)*x25_asy_maxdev, GFP_KERNEL); if (!x25_asy_devs) { printk(KERN_WARNING "X25 async: Can't allocate x25_asy_ctrls[] " "array! Uaargh! (-> No X.25 available)\n"); return -ENOMEM; } memset(x25_asy_devs, 0, sizeof(struct net_device *)*x25_asy_maxdev); 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 = dev->priv; 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_register_ldisc(N_X25, NULL); } module_init(init_x25_asy); module_exit(exit_x25_asy);