isdn_net.c

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/* $Id: isdn_net.c,v 1.140.6.1 2000/12/10 22:01:04 kai Exp $

 * Linux ISDN subsystem, network interfaces and related functions (linklevel).
 *
 * Copyright 1994-1998  by Fritz Elfert ([e-mail])
 * Copyright 1995,96    by Thinking Objects Software GmbH Wuerzburg
 * Copyright 1995,96    by Michael Hipp ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/config.h>
#define __NO_VERSION__
#include <linux/module.h>
#include <linux/isdn.h>
#include <net/arp.h>
#include <net/dst.h>
#include <net/pkt_sched.h>
#include <linux/inetdevice.h>
#include "isdn_common.h"
#include "isdn_net.h"
#ifdef CONFIG_ISDN_PPP
#include "isdn_ppp.h"
#endif
#ifdef CONFIG_ISDN_X25
#include <linux/concap.h>
#include "isdn_concap.h"
#endif


/*
 * Outline of new tbusy handling: 
 *
 * Old method, roughly spoken, consisted of setting tbusy when entering
 * isdn_net_start_xmit() and at several other locations and clearing
 * it from isdn_net_start_xmit() thread when sending was successful.
 *
 * With 2.3.x multithreaded network core, to prevent problems, tbusy should
 * only be set by the isdn_net_start_xmit() thread and only when a tx-busy
 * condition is detected. Other threads (in particular isdn_net_stat_callb())
 * are only allowed to clear tbusy.
 *
 * -HE
 */

/*
 * About SOFTNET:
 * Most of the changes were pretty obvious and basically done by HE already.
 *
 * One problem of the isdn net device code is that is uses struct net_device
 * for masters and slaves. However, only master interface are registered to 
 * the network layer, and therefore, it only makes sense to call netif_* 
 * functions on them.
 *
 * --KG
 */

/* 
 * Find out if the netdevice has been ifup-ed yet.
 * For slaves, look at the corresponding master.
 */
static __inline__ int isdn_net_device_started(isdn_net_dev *n)
{
	isdn_net_local *lp = n->local;
	struct net_device *dev;
	
	if (lp->master) 
		dev = lp->master;
	else
		dev = &n->dev;
	return netif_running(dev);
}

/*
 * wake up the network -> net_device queue.
 * For slaves, wake the corresponding master interface.
 */
static __inline__ void isdn_net_device_wake_queue(isdn_net_local *lp)
{
	if (lp->master) 
		netif_wake_queue(lp->master);
	else
		netif_wake_queue(&lp->netdev->dev);
}

/*
 * stop the network -> net_device queue.
 * For slaves, stop the corresponding master interface.
 */
static __inline__ void isdn_net_device_stop_queue(isdn_net_local *lp)
{
	if (lp->master)
		netif_stop_queue(lp->master);
	else
		netif_stop_queue(&lp->netdev->dev);
}

/*
 * find out if the net_device which this lp belongs to (lp can be
 * master or slave) is busy. It's busy iff all (master and slave) 
 * queues are busy
 */
static __inline__ int isdn_net_device_busy(isdn_net_local *lp)
{
	isdn_net_local *nlp;
	isdn_net_dev *nd;
	unsigned long flags;

	if (!isdn_net_lp_busy(lp))
		return 0;

	if (lp->master)
		nd = ((isdn_net_local *) lp->master->priv)->netdev;
	else
		nd = lp->netdev;
	
	spin_lock_irqsave(&nd->queue_lock, flags);
	nlp = lp->next;
	while (nlp != lp) {
		if (!isdn_net_lp_busy(nlp)) {
			spin_unlock_irqrestore(&nd->queue_lock, flags);
			return 0;
		}
		nlp = nlp->next;
	}
	spin_unlock_irqrestore(&nd->queue_lock, flags);
	return 1;
}

static __inline__ void isdn_net_inc_frame_cnt(isdn_net_local *lp)
{
	atomic_inc(&lp->frame_cnt);
	if (isdn_net_device_busy(lp))
		isdn_net_device_stop_queue(lp);
}

static __inline__ void isdn_net_dec_frame_cnt(isdn_net_local *lp)
{
	atomic_dec(&lp->frame_cnt);

	if (!(isdn_net_device_busy(lp))) {
		if (!skb_queue_empty(&lp->super_tx_queue)) {
			queue_task(&lp->tqueue, &tq_immediate);
		} else {
			isdn_net_device_wake_queue(lp);
		}
       }                                                                      
}

static __inline__ void isdn_net_zero_frame_cnt(isdn_net_local *lp)
{
	atomic_set(&lp->frame_cnt, 0);
}

/* For 2.2.x we leave the transmitter busy timeout at 2 secs, just 
 * to be safe.
 * For 2.3.x we push it up to 20 secs, because call establishment
 * (in particular callback) may take such a long time, and we 
 * don't want confusing messages in the log. However, there is a slight
 * possibility that this large timeout will break other things like MPPP,
 * which might rely on the tx timeout. If so, we'll find out this way...
 */

#define ISDN_NET_TX_TIMEOUT (20*HZ) 

/* Prototypes */

int isdn_net_force_dial_lp(isdn_net_local *);
static int isdn_net_start_xmit(struct sk_buff *, struct net_device *);

char *isdn_net_revision = "$Revision: 1.140.6.1 $";

 /*
  * Code for raw-networking over ISDN
  */

static void
isdn_net_unreachable(struct net_device *dev, struct sk_buff *skb, char *reason)
{
	if(skb) {

		u_short proto = ntohs(skb->protocol);

		printk(KERN_DEBUG "isdn_net: %s: %s, signalling dst_link_failure %s\n",
		       dev->name,
		       (reason != NULL) ? reason : "unknown",
		       (proto != ETH_P_IP) ? "Protocol != ETH_P_IP" : "");
		
		dst_link_failure(skb);
	}
	else {  /* dial not triggered by rawIP packet */
		printk(KERN_DEBUG "isdn_net: %s: %s\n",
			   dev->name,
			   (reason != NULL) ? reason : "reason unknown");
	}
}

static void
isdn_net_reset(struct net_device *dev)
{
#ifdef CONFIG_ISDN_X25
	struct concap_device_ops * dops =
		( (isdn_net_local *) dev->priv ) -> dops;
	struct concap_proto * cprot =
		( (isdn_net_local *) dev->priv ) -> netdev -> cprot;
#endif
	ulong flags;

	/* not sure if the cli() is needed at all --KG */
	save_flags(flags);
	cli();                  /* Avoid glitch on writes to CMD regs */
#ifdef CONFIG_ISDN_X25
	if( cprot && cprot -> pops && dops )
		cprot -> pops -> restart ( cprot, dev, dops );
#endif
	restore_flags(flags);
}

/* Open/initialize the board. */
static int
isdn_net_open(struct net_device *dev)
{
	int i;
	struct net_device *p;
	struct in_device *in_dev;

	/* moved here from isdn_net_reset, because only the master has an
	   interface associated which is supposed to be started. BTW:
	   we need to call netif_start_queue, not netif_wake_queue here */
	netif_start_queue(dev);

	isdn_net_reset(dev);
	/* Fill in the MAC-level header (not needed, but for compatibility... */
	for (i = 0; i < ETH_ALEN - sizeof(u32); i++)
		dev->dev_addr[i] = 0xfc;
	if ((in_dev = dev->ip_ptr) != NULL) {
		/*
		 *      Any address will do - we take the first
		 */
		struct in_ifaddr *ifa = in_dev->ifa_list;
		if (ifa != NULL)
			memcpy(dev->dev_addr+2, &ifa->ifa_local, 4);
	}

	/* If this interface has slaves, start them also */

	if ((p = (((isdn_net_local *) dev->priv)->slave))) {
		while (p) {
			isdn_net_reset(p);
			p = (((isdn_net_local *) p->priv)->slave);
		}
	}
	isdn_MOD_INC_USE_COUNT();
	return 0;
}

/*
 * Assign an ISDN-channel to a net-interface
 */
static void
isdn_net_bind_channel(isdn_net_local * lp, int idx)
{
	ulong flags;

	save_flags(flags);
	cli();
	lp->flags |= ISDN_NET_CONNECTED;
	lp->isdn_device = dev->drvmap[idx];
	lp->isdn_channel = dev->chanmap[idx];
	dev->rx_netdev[idx] = lp->netdev;
	dev->st_netdev[idx] = lp->netdev;
	restore_flags(flags);
}

/*
 * unbind a net-interface (resets interface after an error)
 */
static void
isdn_net_unbind_channel(isdn_net_local * lp)
{
	ulong flags;
	struct sk_buff *skb;

	save_flags(flags);
	cli();
	while ((skb = skb_dequeue(&lp->super_tx_queue))) {
		kfree_skb(skb);
	}
	if (!lp->master) {	/* reset only master device */
		/* Moral equivalent of dev_purge_queues():
		   BEWARE! This chunk of code cannot be called from hardware
		   interrupt handler. I hope it is true. --ANK
		 */
		qdisc_reset(lp->netdev->dev.qdisc);
	}
	lp->dialstate = 0;
	dev->rx_netdev[isdn_dc2minor(lp->isdn_device, lp->isdn_channel)] = NULL;
	dev->st_netdev[isdn_dc2minor(lp->isdn_device, lp->isdn_channel)] = NULL;
	isdn_free_channel(lp->isdn_device, lp->isdn_channel, ISDN_USAGE_NET);
	lp->flags &= ~ISDN_NET_CONNECTED;
	lp->isdn_device = -1;
	lp->isdn_channel = -1;

	restore_flags(flags);
}

/*
 * Perform auto-hangup and cps-calculation for net-interfaces.
 *
 * auto-hangup:
 * Increment idle-counter (this counter is reset on any incoming or
 * outgoing packet), if counter exceeds configured limit either do a
 * hangup immediately or - if configured - wait until just before the next
 * charge-info.
 *
 * cps-calculation (needed for dynamic channel-bundling):
 * Since this function is called every second, simply reset the
 * byte-counter of the interface after copying it to the cps-variable.
 */
unsigned long last_jiffies = -HZ;

void
isdn_net_autohup()
{
	isdn_net_dev *p = dev->netdev;
	int anymore;

	anymore = 0;
	while (p) {
		isdn_net_local *l = p->local;
		if ((jiffies - last_jiffies) == 0)
			l->cps = l->transcount;
		else
			l->cps = (l->transcount * HZ) / (jiffies - last_jiffies);
		l->transcount = 0;
		if (dev->net_verbose > 3)
			printk(KERN_DEBUG "%s: %d bogocps\n", l->name, l->cps);
		if ((l->flags & ISDN_NET_CONNECTED) && (!l->dialstate)) {
			anymore = 1;
			l->huptimer++;
			/*
			 * if there is some dialmode where timeout-hangup
			 * should _not_ be done, check for that here
			 */
			if ((l->onhtime) &&
			    (l->huptimer > l->onhtime))
			{
				if (l->hupflags & ISDN_MANCHARGE &&
				    l->hupflags & ISDN_CHARGEHUP) {
					while (jiffies - l->chargetime > l->chargeint)
						l->chargetime += l->chargeint;
					if (jiffies - l->chargetime >= l->chargeint - 2 * HZ)
						if (l->outgoing || l->hupflags & ISDN_INHUP)
							isdn_net_hangup(&p->dev);
				} else if (l->outgoing) {
					if (l->hupflags & ISDN_CHARGEHUP) {
						if (l->hupflags & ISDN_WAITCHARGE) {
							printk(KERN_DEBUG "isdn_net: Hupflags of %s are %X\n",
							       l->name, l->hupflags);
							isdn_net_hangup(&p->dev);
						} else if (jiffies - l->chargetime > l->chargeint) {
							printk(KERN_DEBUG
							       "isdn_net: %s: chtime = %lu, chint = %d\n",
							       l->name, l->chargetime, l->chargeint);
							isdn_net_hangup(&p->dev);
						}
					} else
						isdn_net_hangup(&p->dev);
				} else if (l->hupflags & ISDN_INHUP)
					isdn_net_hangup(&p->dev);
			}

			if(dev->global_flags & ISDN_GLOBAL_STOPPED || (ISDN_NET_DIALMODE(*l) == ISDN_NET_DM_OFF)) {
				isdn_net_hangup(&p->dev);
				break;
			}
		}
		p = (isdn_net_dev *) p->next;
	}
	last_jiffies = jiffies;
	isdn_timer_ctrl(ISDN_TIMER_NETHANGUP, anymore);
}

static void isdn_net_lp_disconnected(isdn_net_local *lp)
{
	isdn_net_rm_from_bundle(lp);
}

/*
 * Handle status-messages from ISDN-interfacecard.
 * This function is called from within the main-status-dispatcher
 * isdn_status_callback, which itself is called from the low-level driver.
 * Return: 1 = Event handled, 0 = not for us or unknown Event.
 */
int
isdn_net_stat_callback(int idx, isdn_ctrl *c)
{
	isdn_net_dev *p = dev->st_netdev[idx];
	int cmd = c->command;

	if (p) {
		isdn_net_local *lp = p->local;
#ifdef CONFIG_ISDN_X25
		struct concap_proto *cprot = lp -> netdev -> cprot;
		struct concap_proto_ops *pops = cprot ? cprot -> pops : 0;
#endif
		switch (cmd) {
			case ISDN_STAT_BSENT:
				/* A packet has successfully been sent out */
				if ((lp->flags & ISDN_NET_CONNECTED) &&
				    (!lp->dialstate)) {
					isdn_net_dec_frame_cnt(lp);
					lp->stats.tx_packets++;
					lp->stats.tx_bytes += c->parm.length;
				}
				return 1;
			case ISDN_STAT_DCONN:
				/* D-Channel is up */
				switch (lp->dialstate) {
					case 4:
					case 7:
					case 8:
						lp->dialstate++;
						return 1;
					case 12:
						lp->dialstate = 5;
						return 1;
				}
				break;
			case ISDN_STAT_DHUP:
				/* Either D-Channel-hangup or error during dialout */
#ifdef CONFIG_ISDN_X25
				/* If we are not connencted then dialing had
				   failed. If there are generic encap protocol
				   receiver routines signal the closure of
				   the link*/

				if( !(lp->flags & ISDN_NET_CONNECTED)
				    && pops && pops -> disconn_ind )
					pops -> disconn_ind(cprot);
#endif /* CONFIG_ISDN_X25 */
				if ((!lp->dialstate) && (lp->flags & ISDN_NET_CONNECTED)) {
#ifdef CONFIG_ISDN_PPP
					if (lp->p_encap == ISDN_NET_ENCAP_SYNCPPP)
						isdn_ppp_free(lp);
#endif
					isdn_net_lp_disconnected(lp);
					isdn_all_eaz(lp->isdn_device, lp->isdn_channel);
					printk(KERN_INFO "%s: remote hangup\n", lp->name);
					printk(KERN_INFO "%s: Chargesum is %d\n", lp->name,
					       lp->charge);
					isdn_net_unbind_channel(lp);
					return 1;
				}
				break;
#ifdef CONFIG_ISDN_X25
			case ISDN_STAT_BHUP:
				/* B-Channel-hangup */
				/* try if there are generic encap protocol
				   receiver routines and signal the closure of
				   the link */
				if( pops  &&  pops -> disconn_ind ){
						pops -> disconn_ind(cprot);
						return 1;