isdn_net.c

讲述linux的初始化过程

	int si2;
	int ematch;
	int wret;
	int swapped;
	int sidx = 0;
	isdn_net_dev *p;
	isdn_net_phone *n;
	ulong flags;
	char nr[32];
	/* Search name in netdev-chain */
	save_flags(flags);
	cli();
	if (!setup->phone[0]) {
		nr[0] = '0';
		nr[1] = '\0';
		printk(KERN_INFO "isdn_net: Incoming call without OAD, assuming '0'\n");
	} else
		strcpy(nr, setup->phone);
	si1 = (int) setup->si1;
	si2 = (int) setup->si2;
	if (!setup->eazmsn[0]) {
		printk(KERN_WARNING "isdn_net: Incoming call without CPN, assuming '0'\n");
		eaz = "0";
	} else
		eaz = setup->eazmsn;
	if (dev->net_verbose > 1)
		printk(KERN_INFO "isdn_net: call from %s,%d,%d -> %s\n", nr, si1, si2, eaz);
	/* Accept only calls with Si1 = 7 (Data-Transmission) */
	if (si1 != 7) {
		restore_flags(flags);
		if (dev->net_verbose > 1)
			printk(KERN_INFO "isdn_net: Service-Indicator not 7, ignored\n");
		return 0;
	}
	n = (isdn_net_phone *) 0;
	p = dev->netdev;
	ematch = wret = swapped = 0;
#ifdef ISDN_DEBUG_NET_ICALL
	printk(KERN_DEBUG "n_fi: di=%d ch=%d idx=%d usg=%d\n", di, ch, idx,
	       dev->usage[idx]);
#endif
	while (p) {
		int matchret;
		isdn_net_local *lp = p->local;

		/* If last check has triggered as binding-swap, revert it */
		switch (swapped) {
			case 2:
				isdn_net_swap_usage(idx, sidx);
				/* fall through */
			case 1:
				isdn_net_swapbind(di);
				break;
		}
		swapped = 0;
		if (!(matchret = isdn_msncmp(eaz, isdn_map_eaz2msn(lp->msn, di))))
			ematch = 1;
		/* Remember if more numbers eventually can match */
		if (matchret > wret)
			wret = matchret;
#ifdef ISDN_DEBUG_NET_ICALL
		printk(KERN_DEBUG "n_fi: if='%s', l.msn=%s, l.flags=%d, l.dstate=%d\n",
		       lp->name, lp->msn, lp->flags, lp->dialstate);
#endif
		if ((!matchret) &&                                        /* EAZ is matching   */
		    (((!(lp->flags & ISDN_NET_CONNECTED)) &&              /* but not connected */
		      (USG_NONE(dev->usage[idx]))) ||                     /* and ch. unused or */
		     ((((lp->dialstate == 4) || (lp->dialstate == 12)) && /* if dialing        */
		       (!(lp->flags & ISDN_NET_CALLBACK)))                /* but no callback   */
		     )))
			 {
#ifdef ISDN_DEBUG_NET_ICALL
			printk(KERN_DEBUG "n_fi: match1, pdev=%d pch=%d\n",
			       lp->pre_device, lp->pre_channel);
#endif
			if (dev->usage[idx] & ISDN_USAGE_EXCLUSIVE) {
				if ((lp->pre_channel != ch) ||
				    (lp->pre_device != di)) {
					/* Here we got a problem:
					 * If using an ICN-Card, an incoming call is always signaled on
					 * on the first channel of the card, if both channels are
					 * down. However this channel may be bound exclusive. If the
					 * second channel is free, this call should be accepted.
					 * The solution is horribly but it runs, so what:
					 * We exchange the exclusive bindings of the two channels, the
					 * corresponding variables in the interface-structs.
					 */
					if (ch == 0) {
						sidx = isdn_dc2minor(di, 1);
#ifdef ISDN_DEBUG_NET_ICALL
						printk(KERN_DEBUG "n_fi: ch is 0\n");
#endif
						if (USG_NONE(dev->usage[sidx])) {
							/* Second Channel is free, now see if it is bound
							 * exclusive too. */
							if (dev->usage[sidx] & ISDN_USAGE_EXCLUSIVE) {
#ifdef ISDN_DEBUG_NET_ICALL
								printk(KERN_DEBUG "n_fi: 2nd channel is down and bound\n");
#endif
								/* Yes, swap bindings only, if the original
								 * binding is bound to channel 1 of this driver */
								if ((lp->pre_device == di) &&
								    (lp->pre_channel == 1)) {
									isdn_net_swapbind(di);
									swapped = 1;
								} else {
									/* ... else iterate next device */
									p = (isdn_net_dev *) p->next;
									continue;
								}
							} else {
#ifdef ISDN_DEBUG_NET_ICALL
								printk(KERN_DEBUG "n_fi: 2nd channel is down and unbound\n");
#endif
								/* No, swap always and swap excl-usage also */
								isdn_net_swap_usage(idx, sidx);
								isdn_net_swapbind(di);
								swapped = 2;
							}
							/* Now check for exclusive binding again */
#ifdef ISDN_DEBUG_NET_ICALL
							printk(KERN_DEBUG "n_fi: final check\n");
#endif
							if ((dev->usage[idx] & ISDN_USAGE_EXCLUSIVE) &&
							    ((lp->pre_channel != ch) ||
							     (lp->pre_device != di))) {
#ifdef ISDN_DEBUG_NET_ICALL
								printk(KERN_DEBUG "n_fi: final check failed\n");
#endif
								p = (isdn_net_dev *) p->next;
								continue;
							}
						}
					} else {
						/* We are already on the second channel, so nothing to do */
#ifdef ISDN_DEBUG_NET_ICALL
						printk(KERN_DEBUG "n_fi: already on 2nd channel\n");
#endif
					}
				}
			}
#ifdef ISDN_DEBUG_NET_ICALL
			printk(KERN_DEBUG "n_fi: match2\n");
#endif
			n = lp->phone[0];
			if (lp->flags & ISDN_NET_SECURE) {
				while (n) {
					if (!isdn_msncmp(nr, n->num))
						break;
					n = (isdn_net_phone *) n->next;
				}
			}
			if (n || (!(lp->flags & ISDN_NET_SECURE))) {
#ifdef ISDN_DEBUG_NET_ICALL
				printk(KERN_DEBUG "n_fi: match3\n");
#endif
				/* matching interface found */

				/*
				 * Is the state STOPPED?
				 * If so, no dialin is allowed,
				 * so reject actively.
				 * */
				if (ISDN_NET_DIALMODE(*lp) == ISDN_NET_DM_OFF) {
					restore_flags(flags);
					printk(KERN_INFO "incoming call, interface %s `stopped' -> rejected\n",
					       lp->name);
					return 3;
				}
				/*
				 * Is the interface up?
				 * If not, reject the call actively.
				 */
				if (!isdn_net_device_started(p)) {
					restore_flags(flags);
					printk(KERN_INFO "%s: incoming call, interface down -> rejected\n",
					       lp->name);
					return 3;
				}
				/* Interface is up, now see if it's a slave. If so, see if
				 * it's master and parent slave is online. If not, reject the call.
				 */
				if (lp->master) {
					isdn_net_local *mlp = (isdn_net_local *) lp->master->priv;
					printk(KERN_DEBUG "ICALLslv: %s\n", lp->name);
					printk(KERN_DEBUG "master=%s\n", mlp->name);
					if (mlp->flags & ISDN_NET_CONNECTED) {
						printk(KERN_DEBUG "master online\n");
						/* Master is online, find parent-slave (master if first slave) */
						while (mlp->slave) {
							if ((isdn_net_local *) mlp->slave->priv == lp)
								break;
							mlp = (isdn_net_local *) mlp->slave->priv;
						}
					} else
						printk(KERN_DEBUG "master offline\n");
					/* Found parent, if it's offline iterate next device */
					printk(KERN_DEBUG "mlpf: %d\n", mlp->flags & ISDN_NET_CONNECTED);
					if (!(mlp->flags & ISDN_NET_CONNECTED)) {
						p = (isdn_net_dev *) p->next;
						continue;
					}
				} 
				if (lp->flags & ISDN_NET_CALLBACK) {
					int chi;
					/*
					 * Is the state MANUAL?
					 * If so, no callback can be made,
					 * so reject actively.
					 * */
					if (ISDN_NET_DIALMODE(*lp) == ISDN_NET_DM_OFF) {
						restore_flags(flags);
						printk(KERN_INFO "incoming call for callback, interface %s `off' -> rejected\n",
						       lp->name);
						return 3;
					}
					printk(KERN_DEBUG "%s: call from %s -> %s, start callback\n",
					       lp->name, nr, eaz);
					if (lp->phone[1]) {
						/* Grab a free ISDN-Channel */
						if ((chi = 
							isdn_get_free_channel(
								ISDN_USAGE_NET,
								lp->l2_proto,
								lp->l3_proto,
							  	lp->pre_device,
						 		lp->pre_channel,
						 		lp->msn)
								) < 0) {

							printk(KERN_WARNING "isdn_net_find_icall: No channel for %s\n", lp->name);
							restore_flags(flags);
							return 0;
						}
						/* Setup dialstate. */
						lp->dtimer = 0;
						lp->dialstate = 11;
						/* Connect interface with channel */
						isdn_net_bind_channel(lp, chi);
#ifdef CONFIG_ISDN_PPP
						if (lp->p_encap == ISDN_NET_ENCAP_SYNCPPP)
							if (isdn_ppp_bind(lp) < 0) {
								isdn_net_unbind_channel(lp);
								restore_flags(flags);
								return 0;
							}
#endif
						/* Initiate dialing by returning 2 or 4 */
						restore_flags(flags);
						return (lp->flags & ISDN_NET_CBHUP) ? 2 : 4;
					} else
						printk(KERN_WARNING "isdn_net: %s: No phone number\n", lp->name);
					restore_flags(flags);
					return 0;
				} else {
					printk(KERN_DEBUG "%s: call from %s -> %s accepted\n", lp->name, nr,
					       eaz);
					/* if this interface is dialing, it does it probably on a different
					   device, so free this device */
					if ((lp->dialstate == 4) || (lp->dialstate == 12)) {
#ifdef CONFIG_ISDN_PPP
						if (lp->p_encap == ISDN_NET_ENCAP_SYNCPPP)
							isdn_ppp_free(lp);
#endif
						isdn_net_lp_disconnected(lp);
						isdn_free_channel(lp->isdn_device, lp->isdn_channel,
							 ISDN_USAGE_NET);
					}
					dev->usage[idx] &= ISDN_USAGE_EXCLUSIVE;
					dev->usage[idx] |= ISDN_USAGE_NET;
					strcpy(dev->num[idx], nr);
					isdn_info_update();
					dev->st_netdev[idx] = lp->netdev;
					lp->isdn_device = di;
					lp->isdn_channel = ch;
					lp->ppp_slot = -1;
					lp->flags |= ISDN_NET_CONNECTED;
					lp->dialstate = 7;
					lp->dtimer = 0;
					lp->outgoing = 0;
					lp->huptimer = 0;
					lp->hupflags |= ISDN_WAITCHARGE;
					lp->hupflags &= ~ISDN_HAVECHARGE;
#ifdef CONFIG_ISDN_PPP
					if (lp->p_encap == ISDN_NET_ENCAP_SYNCPPP)
						if (isdn_ppp_bind(lp) < 0) {
							isdn_net_unbind_channel(lp);
							restore_flags(flags);
							return 0;
						}
#endif
					restore_flags(flags);
					return 1;
				}
			}
		}
		p = (isdn_net_dev *) p->next;
	}
	/* If none of configured EAZ/MSN matched and not verbose, be silent */
	if (!ematch || dev->net_verbose)
		printk(KERN_INFO "isdn_net: call from %s -> %d %s ignored\n", nr, di, eaz);
	restore_flags(flags);
	return (wret == 2)?5:0;
}

/*
 * Search list of net-interfaces for an interface with given name.
 */
isdn_net_dev *
isdn_net_findif(char *name)
{
	isdn_net_dev *p = dev->netdev;

	while (p) {
		if (!strcmp(p->local->name, name))
			return p;
		p = (isdn_net_dev *) p->next;
	}
	return (isdn_net_dev *) NULL;
}

/*
 * Force a net-interface to dial out.
 * This is called from the userlevel-routine below or
 * from isdn_net_start_xmit().
 */
int
isdn_net_force_dial_lp(isdn_net_local * lp)
{
	if ((!(lp->flags & ISDN_NET_CONNECTED)) && !lp->dialstate) {
		int chi;
		if (lp->phone[1]) {
			ulong flags;
			save_flags(flags);
			cli();

			/* Grab a free ISDN-Channel */
			if ((chi = 
						isdn_get_free_channel(
							ISDN_USAGE_NET,
							lp->l2_proto,
							lp->l3_proto,
							lp->pre_device,
						 	lp->pre_channel,
							lp->msn)
							) < 0) {
				printk(KERN_WARNING "isdn_net_force_dial: No channel for %s\n", lp->name);
				restore_flags(flags);
				return -EAGAIN;
			}
			lp->dialstate = 1;
			/* Connect interface with channel */
			isdn_net_bind_channel(lp, chi);
#ifdef CONFIG_ISDN_PPP
			if (lp->p_encap == ISDN_NET_ENCAP_SYNCPPP)
				if (isdn_ppp_bind(lp) < 0) {
					isdn_net_unbind_channel(lp);
					restore_flags(flags);
					return -EAGAIN;
				}
#endif
			/* Initiate dialing */
			restore_flags(flags);
			isdn_net_dial();
			return 0;
		} else
			return -EINVAL;
	} else
		return -EBUSY;
}

/*
 * This is called from certain upper protocol layers (multilink ppp
 * and x25iface encapsulation module) that want to initiate dialing
 * themselves.
 */
int
isdn_net_dial_req(isdn_net_local * lp)
{
	/* is there a better error code? */
	if (!(ISDN_NET_DIALMODE(*lp) == ISDN_NET_DM_AUTO)) return -EBUSY;

	return isdn_net_force_dial_lp(lp);
}

/*
 * Force a net-interface to dial out.
 * This is always called from within userspace (ISDN_IOCTL_NET_DIAL).
 */
int
isdn_net_force_dial(char *name)
{
	isdn_net_dev *p = isdn_net_findif(name);

	if (!p)
		return -ENODEV;
	return (isdn_net_force_dial_lp(p->local));
}

/*
 * Allocate a new network-interface and initialize its data structures.
 */
char *
isdn_net_new(char *name, struct net_device *master)
{
	isdn_net_dev *netdev;

	/* Avoid creating an existing interface */
	if (isdn_net_findif(name)) {
		printk(KERN_WARNING "isdn_net: interface %s already exists\n", name);
		return NULL;
	}
	if (!(netdev = (isdn_net_dev *) kmalloc(sizeof(isdn_net_dev), GFP_KERNEL))) {
		printk(KERN_WARNING "isdn_net: Could not allocate net-device\n");
		return NULL;
	}
	memset(netdev, 0, sizeof(isdn_net_dev));
	if (!(netdev->local = (isdn_net_local *) kmalloc(sizeof(isdn_net_local), GFP_KERNEL))) {
		printk(KERN_WARNING "isdn_net: Could not allocate device locals\n");
		return NULL;
	}
	memset(netdev->local, 0, sizeof(isdn_net_local));
	if (name == NULL)
		strcpy(netdev->local->name, "         ");
	else
		strcpy(netdev->local->name, name);
	strcpy(netdev->dev.name, netdev->local->name);
	netdev->dev.priv = netdev->local;
	netdev->dev.init = isdn_net_init;
	netdev->local->p_encap = ISDN_NET_ENCAP_RAWIP;
	if (master) {
		/* Device shall be a slave */
		struct net_device *p = (((isdn_net_local *) master->priv)->slave);
		struct net_device *q = master;

		netdev->local->master = master;
		/* Put device at end of slave-chain */
		while (p) {
			q = p;
			p = (((isdn_net_local *) p->priv)->slave);
		}
		((isdn_net_local *) q->priv)->slave = &(netdev->dev);
	} else {
		/* Device shall be a master */
		/*
		 * Watchdog timer (currently) for master only.
		 */
		netdev->dev.tx_timeout = isdn_net_tx_timeout;
		netdev->dev.watchdog_timeo = ISDN_NET_TX_TIMEOUT;
		if (register_netdev(&netdev->dev) != 0) {
			printk(KERN_WARNING "isdn_net: Could not register net-device\n");
			kfree(netdev->local);
			kfree(netdev);
			return NULL;
		}
	}
	netdev->local->magic = ISDN_NET_MAGIC;

	netdev->queue = netdev->local;
	spin_lock_init(&netdev->queue_lock);

	netdev->local->last = netdev->local;
	netdev->local->netdev = netdev;
	netdev->local->next = netdev->local;

	netdev->local->tqueue.sync = 0;
	netdev->local->tqueue.routine = isdn_net_softint;
	netdev->local->tqueue.data = netdev->local;
	spin_lock_init(&netdev->local->xmit_lock);

	netdev->local->isdn_device = -1;
	netdev->local->isdn_channel = -1;
	netdev->local->pre_device = -1;
	netdev->local->pre_channel = -1;
	netdev->local->exclusive = -1;
	netdev->local->ppp_slot = -1;
	netdev->local->pp