ddp.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

	spin_lock_bh(&atalk_iface_lock);
	for (iface = atalk_iface_list; iface; iface = iface->next) {
		if ((node == ATADDR_BCAST ||
		     node == ATADDR_ANYNODE ||
		     iface->address.s_node == node) &&
		    iface->address.s_net == net &&
		    !(iface->status & ATIF_PROBE))
			break;

		/* XXXX.0 -- net.0 returns the iface associated with net */
		if (node == ATADDR_ANYNODE && net != ATADDR_ANYNET &&
		    ntohs(iface->nets.nr_firstnet) <= ntohs(net) &&
		    ntohs(net) <= ntohs(iface->nets.nr_lastnet))
		        break;
	}
	spin_unlock_bh(&atalk_iface_lock);
	return iface;
}


/*
 * Find a route for an AppleTalk packet. This ought to get cached in
 * the socket (later on...). We know about host routes and the fact
 * that a route must be direct to broadcast.
 */
static struct atalk_route *atrtr_find(struct at_addr *target)
{
	/*
	 * we must search through all routes unless we find a 
	 * host route, because some host routes might overlap
	 * network routes
	 */
	struct atalk_route *net_route = NULL;
	struct atalk_route *r;
	
	read_lock_bh(&atalk_router_lock);
	for (r = atalk_router_list; r; r = r->next) {
		if (!(r->flags & RTF_UP))
			continue;

		if (r->target.s_net == target->s_net) {
			if (r->flags & RTF_HOST) {
				/*
				 * if this host route is for the target,
				 * the we're done
				 */
				if (r->target.s_node == target->s_node)
					goto out;
			} else
				/*
				 * this route will work if there isn't a
				 * direct host route, so cache it
				 */
				net_route = r;
		}
	}
	
	/* 
	 * if we found a network route but not a direct host
	 * route, then return it
	 */
	if (net_route)
		r = net_route;
	else if (atrtr_default.dev)
		r = &atrtr_default;
	else /* No route can be found */
		r = NULL;
out:	read_unlock_bh(&atalk_router_lock);
	return r;
}


/*
 * Given an AppleTalk network, find the device to use. This can be
 * a simple lookup.
 */
struct net_device *atrtr_get_dev(struct at_addr *sa)
{
	struct atalk_route *atr = atrtr_find(sa);
	return atr ? atr->dev : NULL;
}

/* Set up a default router */
static void atrtr_set_default(struct net_device *dev)
{
	atrtr_default.dev = dev;
	atrtr_default.flags = RTF_UP;
	atrtr_default.gateway.s_net = htons(0);
	atrtr_default.gateway.s_node = 0;
}

/*
 * Add a router. Basically make sure it looks valid and stuff the
 * entry in the list. While it uses netranges we always set them to one
 * entry to work like netatalk.
 */
static int atrtr_create(struct rtentry *r, struct net_device *devhint)
{
	struct sockaddr_at *ta = (struct sockaddr_at *)&r->rt_dst;
	struct sockaddr_at *ga = (struct sockaddr_at *)&r->rt_gateway;
	struct atalk_route *rt;
	struct atalk_iface *iface, *riface;
	int retval;

	/*
	 * Fixme: Raise/Lower a routing change semaphore for these
	 * operations.
	 */

	/* Validate the request */
	if (ta->sat_family != AF_APPLETALK)
		return -EINVAL;

	if (!devhint && ga->sat_family != AF_APPLETALK)
		return -EINVAL;

	/* Now walk the routing table and make our decisions */
	write_lock_bh(&atalk_router_lock);
	for (rt = atalk_router_list; rt; rt = rt->next) {
		if (r->rt_flags != rt->flags)
			continue;

		if (ta->sat_addr.s_net == rt->target.s_net) {
			if (!(rt->flags & RTF_HOST))
				break;
			if (ta->sat_addr.s_node == rt->target.s_node)
				break;
		}
	}

	if (!devhint) {
		riface = NULL;

		spin_lock_bh(&atalk_iface_lock);
		for (iface = atalk_iface_list; iface; iface = iface->next) {
			if (!riface &&
			    ntohs(ga->sat_addr.s_net) >=
			    		ntohs(iface->nets.nr_firstnet) &&
			    ntohs(ga->sat_addr.s_net) <=
			    		ntohs(iface->nets.nr_lastnet))
				riface = iface;

			if (ga->sat_addr.s_net == iface->address.s_net &&
			    ga->sat_addr.s_node == iface->address.s_node)
				riface = iface;
		}		
		spin_unlock_bh(&atalk_iface_lock);

		retval = -ENETUNREACH;
		if (!riface)
			goto out;

		devhint = riface->dev;
	}

	if (!rt) {
		rt = kmalloc(sizeof(struct atalk_route), GFP_ATOMIC);

		retval = -ENOBUFS;
		if (!rt)
			goto out;

		rt->next = atalk_router_list;
		atalk_router_list = rt;
	}

	/* Fill in the routing entry */
	rt->target  = ta->sat_addr;
	rt->dev     = devhint;
	rt->flags   = r->rt_flags;
	rt->gateway = ga->sat_addr;

	retval = 0;
out:	write_unlock_bh(&atalk_router_lock);
	return retval;
}

/* Delete a route. Find it and discard it */
static int atrtr_delete(struct at_addr * addr)
{
	struct atalk_route **r = &atalk_router_list;
	int retval = 0;
	struct atalk_route *tmp;

	write_lock_bh(&atalk_router_lock);
	while ((tmp = *r) != NULL) {
		if (tmp->target.s_net == addr->s_net &&
		    (!(tmp->flags&RTF_GATEWAY) ||
		     tmp->target.s_node == addr->s_node)) {
			*r = tmp->next;
			kfree(tmp);
			goto out;
		}
		r = &tmp->next;
	}
	retval = -ENOENT;
out:	write_unlock_bh(&atalk_router_lock);
	return retval;
}

/*
 * Called when a device is downed. Just throw away any routes
 * via it.
 */
void atrtr_device_down(struct net_device *dev)
{
	struct atalk_route **r = &atalk_router_list;
	struct atalk_route *tmp;

	write_lock_bh(&atalk_router_lock);
	while ((tmp = *r) != NULL) {
		if (tmp->dev == dev) {
			*r = tmp->next;
			kfree(tmp);
		} else
			r = &tmp->next;
	}
	write_unlock_bh(&atalk_router_lock);

	if (atrtr_default.dev == dev)
		atrtr_set_default(NULL);
}

/* Actually down the interface */
static inline void atalk_dev_down(struct net_device *dev)
{
	atrtr_device_down(dev);	/* Remove all routes for the device */
	aarp_device_down(dev);	/* Remove AARP entries for the device */
	atif_drop_device(dev);	/* Remove the device */
}

/*
 * A device event has occurred. Watch for devices going down and
 * delete our use of them (iface and route).
 */
static int ddp_device_event(struct notifier_block *this, unsigned long event,
				void *ptr)
{
	if (event == NETDEV_DOWN)
		/* Discard any use of this */
	        atalk_dev_down((struct net_device *) ptr);

	return NOTIFY_DONE;
}

/* ioctl calls. Shouldn't even need touching */
/* Device configuration ioctl calls */
static int atif_ioctl(int cmd, void *arg)
{
	static char aarp_mcast[6] = {0x09, 0x00, 0x00, 0xFF, 0xFF, 0xFF};
	struct ifreq atreq;
	struct netrange *nr;
	struct sockaddr_at *sa;
	struct net_device *dev;
	struct atalk_iface *atif;
	int ct;
	int limit;
	struct rtentry rtdef;
	int add_route;

	if (copy_from_user(&atreq, arg, sizeof(atreq)))
		return -EFAULT;

	dev = __dev_get_by_name(atreq.ifr_name);
	if (!dev)
		return -ENODEV;

	sa = (struct sockaddr_at*) &atreq.ifr_addr;
	atif = atalk_find_dev(dev);

	switch (cmd) {
		case SIOCSIFADDR:
			if (!capable(CAP_NET_ADMIN))
				return -EPERM;
			if (sa->sat_family != AF_APPLETALK)
				return -EINVAL;
			if (dev->type != ARPHRD_ETHER &&
			    dev->type != ARPHRD_LOOPBACK &&
			    dev->type != ARPHRD_LOCALTLK &&
			    dev->type != ARPHRD_PPP)
				return -EPROTONOSUPPORT;

			nr = (struct netrange *) &sa->sat_zero[0];
			add_route = 1;

			/*
			 * if this is a point-to-point iface, and we already
			 * have an iface for this AppleTalk address, then we
			 * should not add a route
			 */
			if ((dev->flags & IFF_POINTOPOINT) &&
			    atalk_find_interface(sa->sat_addr.s_net,
				    		 sa->sat_addr.s_node)) {
				printk(KERN_DEBUG "AppleTalk: point-to-point "
						  "interface added with "
						  "existing address\n");
				add_route = 0;
			}
			
			/*
			 * Phase 1 is fine on LocalTalk but we don't do
			 * EtherTalk phase 1. Anyone wanting to add it go ahead.
			 */
			if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
				return -EPROTONOSUPPORT;
			if (sa->sat_addr.s_node == ATADDR_BCAST ||
			    sa->sat_addr.s_node == 254)
				return -EINVAL;
			if (atif) {
				/* Already setting address */
				if (atif->status & ATIF_PROBE)
					return -EBUSY;

				atif->address.s_net  = sa->sat_addr.s_net;
				atif->address.s_node = sa->sat_addr.s_node;
				atrtr_device_down(dev);	/* Flush old routes */
			} else {
				atif = atif_add_device(dev, &sa->sat_addr);
				if (!atif)
					return -ENOMEM;
			}
			atif->nets = *nr;

			/*
			 * Check if the chosen address is used. If so we
			 * error and atalkd will try another.
			 */

			if (!(dev->flags & IFF_LOOPBACK) &&
			    !(dev->flags & IFF_POINTOPOINT) &&
			    atif_probe_device(atif) < 0) {
				atif_drop_device(dev);
				return -EADDRINUSE;
			}

			/* Hey it worked - add the direct routes */
			sa = (struct sockaddr_at *) &rtdef.rt_gateway;
			sa->sat_family = AF_APPLETALK;
			sa->sat_addr.s_net  = atif->address.s_net;
			sa->sat_addr.s_node = atif->address.s_node;
			sa = (struct sockaddr_at *) &rtdef.rt_dst;
			rtdef.rt_flags = RTF_UP;
			sa->sat_family = AF_APPLETALK;
			sa->sat_addr.s_node = ATADDR_ANYNODE;
			if (dev->flags & IFF_LOOPBACK ||
			    dev->flags & IFF_POINTOPOINT)
				rtdef.rt_flags |= RTF_HOST;

			/* Routerless initial state */
			if (nr->nr_firstnet == htons(0) &&
			    nr->nr_lastnet == htons(0xFFFE)) {
				sa->sat_addr.s_net = atif->address.s_net;
				atrtr_create(&rtdef, dev);
				atrtr_set_default(dev);
			} else {
				limit = ntohs(nr->nr_lastnet);
				if (limit - ntohs(nr->nr_firstnet) > 4096) {
					printk(KERN_WARNING "Too many routes/"
							    "iface.\n");
					return -EINVAL;
				}
				if (add_route)
					for (ct = ntohs(nr->nr_firstnet);
					     ct <= limit; ct++) {
						sa->sat_addr.s_net = htons(ct);
						atrtr_create(&rtdef, dev);
					}
			}
			dev_mc_add(dev, aarp_mcast, 6, 1);
			return 0;

		case SIOCGIFADDR:
			if (!atif)
				return -EADDRNOTAVAIL;

			sa->sat_family = AF_APPLETALK;
			sa->sat_addr = atif->address;
			break;

		case SIOCGIFBRDADDR:
			if (!atif)
				return -EADDRNOTAVAIL;

			sa->sat_family = AF_APPLETALK;
			sa->sat_addr.s_net = atif->address.s_net;
			sa->sat_addr.s_node = ATADDR_BCAST;
			break;

	        case SIOCATALKDIFADDR:
	        case SIOCDIFADDR:
			if (!capable(CAP_NET_ADMIN))
				return -EPERM;
			if (sa->sat_family != AF_APPLETALK)
				return -EINVAL;
			atalk_dev_down(dev);
			break;			

		case SIOCSARP:
			if (!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        if (sa->sat_family != AF_APPLETALK)
                                return -EINVAL;
                        if (!atif)
                                return -EADDRNOTAVAIL;

                        /*
                         * for now, we only support proxy AARP on ELAP;
                         * we should be able to do it for LocalTalk, too.
                         */
                        if (dev->type != ARPHRD_ETHER)
                                return -EPROTONOSUPPORT;

                        /*
                         * atif points to the current interface on this network;
                         * we aren't concerned about its current status (at
			 * least for now), but it has all the settings about
			 * the network we're going to probe. Consequently, it
			 * must exist.
                         */
                        if (!atif)
                                return -EADDRNOTAVAIL;

                        nr = (struct netrange *) &(atif->nets);
                        /*
                         * Phase 1 is fine on Localtalk but we don't do
                         * Ethertalk phase 1. Anyone wanting to add it go ahead.
                         */
                        if (dev->type == ARPHRD_ETHER && nr->nr_phase != 2)
                                return -EPROTONOSUPPORT;

                        if (sa->sat_addr.s_node == ATADDR_BCAST ||
			    sa->sat_addr.s_node == 254)
                                return -EINVAL;

                        /*
                         * Check if the chosen address is used. If so we
                         * error and ATCP will try another.
                         */
                      	if (atif_proxy_probe_device(atif, &(sa->sat_addr)) < 0)
                      		return -EADDRINUSE;
                      	
			/*
                         * We now have an address on the local network, and
			 * the AARP code will defend it for us until we take it
			 * down. We don't set up any routes right now, because
			 * ATCP will install them manually via SIOCADDRT.
                         */
                        break;

                case SIOCDARP:
                        if (!capable(CAP_NET_ADMIN))
                                return -EPERM;
                        if (sa->sat_family != AF_APPLETALK)
                                return -EINVAL;
                        if (!atif)
                                return -EADDRNOTAVAIL;

                        /* give to aarp module to remove proxy entry */
                        aarp_proxy_remove(atif->dev, &(sa->sat_addr));
                        return 0;
	}

	return copy_to_user(arg, &atreq, sizeof(atreq)) ? -EFAULT : 0;
}

/* Routing ioctl() calls */
static int atrtr_ioctl(unsigned int cmd, void *arg)
{
	struct net_device *dev = NULL;
	struct rtentry rt;

	if (copy_from_user(&rt, arg, sizeof(rt)))
		return -EFAULT;

	switch (cmd) {
		case SIOCDELRT:
			if (rt.rt_dst.sa_family != AF_APPLETALK)
				return -EINVAL;
			return atrtr_delete(&((struct sockaddr_at *)
						&rt.rt_dst)->sat_addr);

		case SIOCADDRT:
			/* FIXME: the name of the device is still in user
			 * space, isn't it? */
			if (rt.rt_dev) {
				dev = __dev_get_by_name(rt.rt_dev);
				if (!dev)
					return -ENODEV;
			}			
			return atrtr_create(&rt, dev);
	}
	return -EINVAL;
}

/* Called from proc fs - just make it print the ifaces neatly */
static int atalk_if_get_info(char *buffer, char **start, off_t offset,
			     int length)
{
	off_t pos = 0;
	off_t begin = 0;
	struct atalk_iface *iface;
	int len = sprintf(buffer, "Interface	  Address   "
				  "Networks   Status\n");

	spin_lock_bh(&atalk_iface_lock);
	for (iface = atalk_iface_list; iface; iface = iface->next) {
		len += sprintf(buffer+len,"%-16s %04X:%02X  %04X-%04X  %d\n",