arch/um/drivers/net_kern.c - maze/linux - Git at Google

 /*
  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
  * James Leu (jleu@mindspring.net).
  * Copyright (C) 2001 by various other people who didn't put their name here.
  * Licensed under the GPL.
  */

 #include "linux/kernel.h"
 #include "linux/netdevice.h"
 #include "linux/rtnetlink.h"
 #include "linux/skbuff.h"
 #include "linux/socket.h"
 #include "linux/spinlock.h"
 #include "linux/module.h"
 #include "linux/init.h"
 #include "linux/etherdevice.h"
 #include "linux/list.h"
 #include "linux/inetdevice.h"
 #include "linux/ctype.h"
 #include "linux/bootmem.h"
 #include "linux/ethtool.h"
 #include "linux/platform_device.h"
 #include "asm/uaccess.h"
 #include "user_util.h"
 #include "kern_util.h"
 #include "net_kern.h"
 #include "net_user.h"
 #include "mconsole_kern.h"
 #include "init.h"
 #include "irq_user.h"
 #include "irq_kern.h"

 static inline void set_ether_mac(struct net_device *dev, unsigned char *addr)
 {
 	memcpy(dev->dev_addr, addr, ETH_ALEN);
 }

 #define DRIVER_NAME "uml-netdev"

 static DEFINE_SPINLOCK(opened_lock);
 static LIST_HEAD(opened);

 static int uml_net_rx(struct net_device *dev)
 {
 	struct uml_net_private *lp = dev->priv;
 	int pkt_len;
 	struct sk_buff *skb;

 	/* If we can't allocate memory, try again next round. */
 	skb = dev_alloc_skb(dev->mtu);
 	if (skb == NULL) {
 		lp->stats.rx_dropped++;
 		return 0;
 	}

 	skb->dev = dev;
 	skb_put(skb, dev->mtu);
 	skb_reset_mac_header(skb);
 	pkt_len = (*lp->read)(lp->fd, &skb, lp);

 	if (pkt_len > 0) {
 		skb_trim(skb, pkt_len);
 		skb->protocol = (*lp->protocol)(skb);
 		netif_rx(skb);

 		lp->stats.rx_bytes += skb->len;
 		lp->stats.rx_packets++;
 		return pkt_len;
 	}

 	kfree_skb(skb);
 	return pkt_len;
 }

 static void uml_dev_close(struct work_struct *work)
 {
 	struct uml_net_private *lp =
 		container_of(work, struct uml_net_private, work);
 	dev_close(lp->dev);
 }

 irqreturn_t uml_net_interrupt(int irq, void *dev_id)
 {
 	struct net_device *dev = dev_id;
 	struct uml_net_private *lp = dev->priv;
 	int err;

 	if(!netif_running(dev))
 		return(IRQ_NONE);

 	spin_lock(&lp->lock);
 	while((err = uml_net_rx(dev)) > 0) ;
 	if(err < 0) {
 		printk(KERN_ERR
 		       "Device '%s' read returned %d, shutting it down\n",
 		       dev->name, err);
 		/* dev_close can't be called in interrupt context, and takes
 		 * again lp->lock.
 		 * And dev_close() can be safely called multiple times on the
 		 * same device, since it tests for (dev->flags & IFF_UP). So
 		 * there's no harm in delaying the device shutdown.
 		 * Furthermore, the workqueue will not re-enqueue an already
 		 * enqueued work item. */
 		schedule_work(&lp->work);
 		goto out;
 	}
 	reactivate_fd(lp->fd, UM_ETH_IRQ);

 out:
 	spin_unlock(&lp->lock);
 	return IRQ_HANDLED;
 }

 static int uml_net_open(struct net_device *dev)
 {
 	struct uml_net_private *lp = dev->priv;
 	int err;

 	if(lp->fd >= 0){
 		err = -ENXIO;
 		goto out;
 	}

 	lp->fd = (*lp->open)(&lp->user);
 	if(lp->fd < 0){
 		err = lp->fd;
 		goto out;
 	}

 	err = um_request_irq(dev->irq, lp->fd, IRQ_READ, uml_net_interrupt,
 			     IRQF_DISABLED | IRQF_SHARED, dev->name, dev);
 	if(err != 0){
 		printk(KERN_ERR "uml_net_open: failed to get irq(%d)\n", err);
 		err = -ENETUNREACH;
 		goto out_close;
 	}

 	lp->tl.data = (unsigned long) &lp->user;
 	netif_start_queue(dev);

 	/* clear buffer - it can happen that the host side of the interface
 	 * is full when we get here.  In this case, new data is never queued,
 	 * SIGIOs never arrive, and the net never works.
 	 */
 	while((err = uml_net_rx(dev)) > 0) ;

 	spin_lock(&opened_lock);
 	list_add(&lp->list, &opened);
 	spin_unlock(&opened_lock);

 	return 0;
 out_close:
 	if(lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
 	lp->fd = -1;
 out:
 	return err;
 }

 static int uml_net_close(struct net_device *dev)
 {
 	struct uml_net_private *lp = dev->priv;

 	netif_stop_queue(dev);

 	free_irq(dev->irq, dev);
 	if(lp->close != NULL)
 		(*lp->close)(lp->fd, &lp->user);
 	lp->fd = -1;

 	spin_lock(&opened_lock);
 	list_del(&lp->list);
 	spin_unlock(&opened_lock);

 	return 0;
 }

 static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct uml_net_private *lp = dev->priv;
 	unsigned long flags;
 	int len;

 	netif_stop_queue(dev);

 	spin_lock_irqsave(&lp->lock, flags);

 	len = (*lp->write)(lp->fd, &skb, lp);

 	if(len == skb->len) {
 		lp->stats.tx_packets++;
 		lp->stats.tx_bytes += skb->len;
 		dev->trans_start = jiffies;
 		netif_start_queue(dev);

 		/* this is normally done in the interrupt when tx finishes */
 		netif_wake_queue(dev);
 	}
 	else if(len == 0){
 		netif_start_queue(dev);
 		lp->stats.tx_dropped++;
 	}
 	else {
 		netif_start_queue(dev);
 		printk(KERN_ERR "uml_net_start_xmit: failed(%d)\n", len);
 	}

 	spin_unlock_irqrestore(&lp->lock, flags);

 	dev_kfree_skb(skb);

 	return 0;
 }

 static struct net_device_stats *uml_net_get_stats(struct net_device *dev)
 {
 	struct uml_net_private *lp = dev->priv;
 	return &lp->stats;
 }

 static void uml_net_set_multicast_list(struct net_device *dev)
 {
 	if (dev->flags & IFF_PROMISC) return;
 	else if (dev->mc_count)	dev->flags |= IFF_ALLMULTI;
 	else dev->flags &= ~IFF_ALLMULTI;
 }

 static void uml_net_tx_timeout(struct net_device *dev)
 {
 	dev->trans_start = jiffies;
 	netif_wake_queue(dev);
 }

 static int uml_net_set_mac(struct net_device *dev, void *addr)
 {
 	struct uml_net_private *lp = dev->priv;
 	struct sockaddr *hwaddr = addr;

 	spin_lock_irq(&lp->lock);
 	set_ether_mac(dev, hwaddr->sa_data);
 	spin_unlock_irq(&lp->lock);

 	return 0;
 }

 static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct uml_net_private *lp = dev->priv;
 	int err = 0;

 	spin_lock_irq(&lp->lock);

 	new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
 	if(new_mtu < 0){
 		err = new_mtu;
 		goto out;
 	}

 	dev->mtu = new_mtu;

  out:
 	spin_unlock_irq(&lp->lock);
 	return err;
 }

 static void uml_net_get_drvinfo(struct net_device *dev,
 				struct ethtool_drvinfo *info)
 {
 	strcpy(info->driver, DRIVER_NAME);
 	strcpy(info->version, "42");
 }

 static struct ethtool_ops uml_net_ethtool_ops = {
 	.get_drvinfo	= uml_net_get_drvinfo,
 	.get_link	= ethtool_op_get_link,
 };

 void uml_net_user_timer_expire(unsigned long _conn)
 {
 #ifdef undef
 	struct connection *conn = (struct connection *)_conn;

 	dprintk(KERN_INFO "uml_net_user_timer_expire [%p]\n", conn);
 	do_connect(conn);
 #endif
 }

 static void setup_etheraddr(char *str, unsigned char *addr)
 {
 	char *end;
 	int i;

 	if(str == NULL)
 		goto random;

 	for(i=0;i<6;i++){
 		addr[i] = simple_strtoul(str, &end, 16);
 		if((end == str) ||
 		   ((*end != ':') && (*end != ',') && (*end != '\0'))){
 			printk(KERN_ERR
 			       "setup_etheraddr: failed to parse '%s' "
 			       "as an ethernet address\n", str);
 			goto random;
 		}
 		str = end + 1;
 	}
 	if(addr[0] & 1){
 		printk(KERN_ERR
 		       "Attempt to assign a broadcast ethernet address to a "
 		       "device disallowed\n");
 		goto random;
 	}
 	return;

 random:
 	random_ether_addr(addr);
 }

 static DEFINE_SPINLOCK(devices_lock);
 static LIST_HEAD(devices);

 static struct platform_driver uml_net_driver = {
 	.driver = {
 		.name  = DRIVER_NAME,
 	},
 };
 static int driver_registered;

 static int eth_configure(int n, void *init, char *mac,
 			 struct transport *transport)
 {
 	struct uml_net *device;
 	struct net_device *dev;
 	struct uml_net_private *lp;
 	int save, err, size;

 	size = transport->private_size + sizeof(struct uml_net_private) +
 		sizeof(((struct uml_net_private *) 0)->user);

 	device = kzalloc(sizeof(*device), GFP_KERNEL);
 	if (device == NULL) {
 		printk(KERN_ERR "eth_configure failed to allocate uml_net\n");
 		return(1);
 	}

 	INIT_LIST_HEAD(&device->list);
 	device->index = n;

 	spin_lock(&devices_lock);
 	list_add(&device->list, &devices);
 	spin_unlock(&devices_lock);

 	setup_etheraddr(mac, device->mac);

 	printk(KERN_INFO "Netdevice %d ", n);
 	printk("(%02x:%02x:%02x:%02x:%02x:%02x) ",
 	       device->mac[0], device->mac[1],
 	       device->mac[2], device->mac[3],
 	       device->mac[4], device->mac[5]);
 	printk(": ");
 	dev = alloc_etherdev(size);
 	if (dev == NULL) {
 		printk(KERN_ERR "eth_configure: failed to allocate device\n");
 		return 1;
 	}

 	lp = dev->priv;
 	/* This points to the transport private data. It's still clear, but we
 	 * must memset it to 0 *now*. Let's help the drivers. */
 	memset(lp, 0, size);
 	INIT_WORK(&lp->work, uml_dev_close);

 	/* sysfs register */
 	if (!driver_registered) {
 		platform_driver_register(&uml_net_driver);
 		driver_registered = 1;
 	}
 	device->pdev.id = n;
 	device->pdev.name = DRIVER_NAME;
 	platform_device_register(&device->pdev);
 	SET_NETDEV_DEV(dev,&device->pdev.dev);

 	/* If this name ends up conflicting with an existing registered
 	 * netdevice, that is OK, register_netdev{,ice}() will notice this
 	 * and fail.
 	 */
 	snprintf(dev->name, sizeof(dev->name), "eth%d", n);
 	device->dev = dev;

 	(*transport->kern->init)(dev, init);

 	dev->mtu = transport->user->max_packet;
 	dev->open = uml_net_open;
 	dev->hard_start_xmit = uml_net_start_xmit;
 	dev->stop = uml_net_close;
 	dev->get_stats = uml_net_get_stats;
 	dev->set_multicast_list = uml_net_set_multicast_list;
 	dev->tx_timeout = uml_net_tx_timeout;
 	dev->set_mac_address = uml_net_set_mac;
 	dev->change_mtu = uml_net_change_mtu;
 	dev->ethtool_ops = &uml_net_ethtool_ops;
 	dev->watchdog_timeo = (HZ >> 1);
 	dev->irq = UM_ETH_IRQ;

 	rtnl_lock();
 	err = register_netdevice(dev);
 	rtnl_unlock();
 	if (err) {
 		device->dev = NULL;
 		/* XXX: should we call ->remove() here? */
 		free_netdev(dev);
 		return 1;
 	}

 	/* lp.user is the first four bytes of the transport data, which
 	 * has already been initialized.  This structure assignment will
 	 * overwrite that, so we make sure that .user gets overwritten with
 	 * what it already has.
 	 */
 	save = lp->user[0];
 	*lp = ((struct uml_net_private)
 		{ .list  		= LIST_HEAD_INIT(lp->list),
 		  .dev 			= dev,
 		  .fd 			= -1,
 		  .mac 			= { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
 		  .protocol 		= transport->kern->protocol,
 		  .open 		= transport->user->open,
 		  .close 		= transport->user->close,
 		  .remove 		= transport->user->remove,
 		  .read 		= transport->kern->read,
 		  .write 		= transport->kern->write,
 		  .add_address 		= transport->user->add_address,
 		  .delete_address  	= transport->user->delete_address,
 		  .set_mtu 		= transport->user->set_mtu,
 		  .user  		= { save } });

 	init_timer(&lp->tl);
 	spin_lock_init(&lp->lock);
 	lp->tl.function = uml_net_user_timer_expire;
 	memcpy(lp->mac, device->mac, sizeof(lp->mac));

 	if (transport->user->init)
 		(*transport->user->init)(&lp->user, dev);

 	set_ether_mac(dev, device->mac);

 	return 0;
 }

 static struct uml_net *find_device(int n)
 {
 	struct uml_net *device;
 	struct list_head *ele;

 	spin_lock(&devices_lock);
 	list_for_each(ele, &devices){
 		device = list_entry(ele, struct uml_net, list);
 		if(device->index == n)
 			goto out;
 	}
 	device = NULL;
  out:
 	spin_unlock(&devices_lock);
 	return device;
 }

 static int eth_parse(char *str, int *index_out, char **str_out,
 		     char **error_out)
 {
 	char *end;
 	int n, err = -EINVAL;;

 	n = simple_strtoul(str, &end, 0);
 	if(end == str){
 		*error_out = "Bad device number";
 		return err;
 	}

 	str = end;
 	if(*str != '='){
 		*error_out = "Expected '=' after device number";
 		return err;
 	}

 	str++;
 	if(find_device(n)){
 		*error_out = "Device already configured";
 		return err;
 	}

 	*index_out = n;
 	*str_out = str;
 	return 0;
 }

 struct eth_init {
 	struct list_head list;
 	char *init;
 	int index;
 };

 static DEFINE_SPINLOCK(transports_lock);
 static LIST_HEAD(transports);

 /* Filled in during early boot */
 static LIST_HEAD(eth_cmd_line);

 static int check_transport(struct transport *transport, char *eth, int n,
 			   void **init_out, char **mac_out)
 {
 	int len;

 	len = strlen(transport->name);
 	if(strncmp(eth, transport->name, len))
 		return 0;

 	eth += len;
 	if(*eth == ',')
 		eth++;
 	else if(*eth != '\0')
 		return 0;

 	*init_out = kmalloc(transport->setup_size, GFP_KERNEL);
 	if(*init_out == NULL)
 		return 1;

 	if(!transport->setup(eth, mac_out, *init_out)){
 		kfree(*init_out);
 		*init_out = NULL;
 	}
 	return 1;
 }

 void register_transport(struct transport *new)
 {
 	struct list_head *ele, *next;
 	struct eth_init *eth;
 	void *init;
 	char *mac = NULL;
 	int match;

 	spin_lock(&transports_lock);
 	BUG_ON(!list_empty(&new->list));
 	list_add(&new->list, &transports);
 	spin_unlock(&transports_lock);

 	list_for_each_safe(ele, next, &eth_cmd_line){
 		eth = list_entry(ele, struct eth_init, list);
 		match = check_transport(new, eth->init, eth->index, &init,
 					&mac);
 		if(!match)
 			continue;
 		else if(init != NULL){
 			eth_configure(eth->index, init, mac, new);
 			kfree(init);
 		}
 		list_del(&eth->list);
 	}
 }

 static int eth_setup_common(char *str, int index)
 {
 	struct list_head *ele;
 	struct transport *transport;
 	void *init;
 	char *mac = NULL;
 	int found = 0;

 	spin_lock(&transports_lock);
 	list_for_each(ele, &transports){
 		transport = list_entry(ele, struct transport, list);
 	        if(!check_transport(transport, str, index, &init, &mac))
 			continue;
 		if(init != NULL){
 			eth_configure(index, init, mac, transport);
 			kfree(init);
 		}
 		found = 1;
 		break;
 	}

 	spin_unlock(&transports_lock);
 	return found;
 }

 static int eth_setup(char *str)
 {
 	struct eth_init *new;
 	char *error;
 	int n, err;

 	err = eth_parse(str, &n, &str, &error);
 	if(err){
 		printk(KERN_ERR "eth_setup - Couldn't parse '%s' : %s\n",
 		       str, error);
 		return 1;
 	}

 	new = alloc_bootmem(sizeof(*new));
 	if (new == NULL){
 		printk("eth_init : alloc_bootmem failed\n");
 		return 1;
 	}

 	INIT_LIST_HEAD(&new->list);
 	new->index = n;
 	new->init = str;

 	list_add_tail(&new->list, &eth_cmd_line);
 	return 1;
 }

 __setup("eth", eth_setup);
 __uml_help(eth_setup,
 "eth[0-9]+=<transport>,<options>\n"
 "    Configure a network device.\n\n"
 );

 static int net_config(char *str, char **error_out)
 {
 	int n, err;

 	err = eth_parse(str, &n, &str, error_out);
 	if(err)
 		return err;

 	/* This string is broken up and the pieces used by the underlying
 	 * driver.  So, it is freed only if eth_setup_common fails.
 	 */
 	str = kstrdup(str, GFP_KERNEL);
 	if(str == NULL){
 	        *error_out = "net_config failed to strdup string";
 		return -ENOMEM;
 	}
 	err = !eth_setup_common(str, n);
 	if(err)
 		kfree(str);
 	return(err);
 }

 static int net_id(char **str, int *start_out, int *end_out)
 {
         char *end;
         int n;

 	n = simple_strtoul(*str, &end, 0);
 	if((*end != '\0') || (end == *str))
 		return -1;

         *start_out = n;
         *end_out = n;
         *str = end;
         return n;
 }

 static int net_remove(int n, char **error_out)
 {
 	struct uml_net *device;
 	struct net_device *dev;
 	struct uml_net_private *lp;

 	device = find_device(n);
 	if(device == NULL)
 		return -ENODEV;

 	dev = device->dev;
 	lp = dev->priv;
 	if(lp->fd > 0)
 		return -EBUSY;
 	if(lp->remove != NULL) (*lp->remove)(&lp->user);
 	unregister_netdev(dev);
 	platform_device_unregister(&device->pdev);

 	list_del(&device->list);
 	kfree(device);
 	free_netdev(dev);
 	return 0;
 }

 static struct mc_device net_mc = {
 	.list		= LIST_HEAD_INIT(net_mc.list),
 	.name		= "eth",
 	.config		= net_config,
 	.get_config	= NULL,
 	.id		= net_id,
 	.remove		= net_remove,
 };

 static int uml_inetaddr_event(struct notifier_block *this, unsigned long event,
 			      void *ptr)
 {
 	struct in_ifaddr *ifa = ptr;
 	struct net_device *dev = ifa->ifa_dev->dev;
 	struct uml_net_private *lp;
 	void (*proc)(unsigned char *, unsigned char *, void *);
 	unsigned char addr_buf[4], netmask_buf[4];

 	if(dev->open != uml_net_open)
 		return NOTIFY_DONE;

 	lp = dev->priv;

 	proc = NULL;
 	switch (event){
 	case NETDEV_UP:
 		proc = lp->add_address;
 		break;
 	case NETDEV_DOWN:
 		proc = lp->delete_address;
 		break;
 	}
 	if(proc != NULL){
 		memcpy(addr_buf, &ifa->ifa_address, sizeof(addr_buf));
 		memcpy(netmask_buf, &ifa->ifa_mask, sizeof(netmask_buf));
 		(*proc)(addr_buf, netmask_buf, &lp->user);
 	}
 	return NOTIFY_DONE;
 }

 /* uml_net_init shouldn't be called twice on two CPUs at the same time */
 struct notifier_block uml_inetaddr_notifier = {
 	.notifier_call		= uml_inetaddr_event,
 };

 static int uml_net_init(void)
 {
 	struct list_head *ele;
 	struct uml_net_private *lp;
 	struct in_device *ip;
 	struct in_ifaddr *in;

 	mconsole_register_dev(&net_mc);
 	register_inetaddr_notifier(&uml_inetaddr_notifier);

 	/* Devices may have been opened already, so the uml_inetaddr_notifier
 	 * didn't get a chance to run for them.  This fakes it so that
 	 * addresses which have already been set up get handled properly.
 	 */
 	spin_lock(&opened_lock);
 	list_for_each(ele, &opened){
 		lp = list_entry(ele, struct uml_net_private, list);
 		ip = lp->dev->ip_ptr;
 		if(ip == NULL)
 			continue;
 		in = ip->ifa_list;
 		while(in != NULL){
 			uml_inetaddr_event(NULL, NETDEV_UP, in);
 			in = in->ifa_next;
 		}
 	}
 	spin_unlock(&opened_lock);

 	return 0;
 }

 __initcall(uml_net_init);

 static void close_devices(void)
 {
 	struct list_head *ele;
 	struct uml_net_private *lp;

 	spin_lock(&opened_lock);
 	list_for_each(ele, &opened){
 		lp = list_entry(ele, struct uml_net_private, list);
 		free_irq(lp->dev->irq, lp->dev);
 		if((lp->close != NULL) && (lp->fd >= 0))
 			(*lp->close)(lp->fd, &lp->user);
 		if(lp->remove != NULL)
 			(*lp->remove)(&lp->user);
 	}
 	spin_unlock(&opened_lock);
 }

 __uml_exitcall(close_devices);

 struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra)
 {
 	if((skb != NULL) && (skb_tailroom(skb) < extra)){
 	  	struct sk_buff *skb2;

 		skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
 		dev_kfree_skb(skb);
 		skb = skb2;
 	}
 	if(skb != NULL) skb_put(skb, extra);
 	return(skb);
 }

 void iter_addresses(void *d, void (*cb)(unsigned char *, unsigned char *,
 					void *),
 		    void *arg)
 {
 	struct net_device *dev = d;
 	struct in_device *ip = dev->ip_ptr;
 	struct in_ifaddr *in;
 	unsigned char address[4], netmask[4];

 	if(ip == NULL) return;
 	in = ip->ifa_list;
 	while(in != NULL){
 		memcpy(address, &in->ifa_address, sizeof(address));
 		memcpy(netmask, &in->ifa_mask, sizeof(netmask));
 		(*cb)(address, netmask, arg);
 		in = in->ifa_next;
 	}
 }

 int dev_netmask(void *d, void *m)
 {
 	struct net_device *dev = d;
 	struct in_device *ip = dev->ip_ptr;
 	struct in_ifaddr *in;
 	__be32 *mask_out = m;

 	if(ip == NULL)
 		return(1);

 	in = ip->ifa_list;
 	if(in == NULL)
 		return(1);

 	*mask_out = in->ifa_mask;
 	return(0);
 }

 void *get_output_buffer(int *len_out)
 {
 	void *ret;

 	ret = (void *) __get_free_pages(GFP_KERNEL, 0);
 	if(ret) *len_out = PAGE_SIZE;
 	else *len_out = 0;
 	return ret;
 }

 void free_output_buffer(void *buffer)
 {
 	free_pages((unsigned long) buffer, 0);
 }

 int tap_setup_common(char *str, char *type, char **dev_name, char **mac_out,
 		     char **gate_addr)
 {
 	char *remain;

 	remain = split_if_spec(str, dev_name, mac_out, gate_addr, NULL);
 	if(remain != NULL){
 		printk("tap_setup_common - Extra garbage on specification : "
 		       "'%s'\n", remain);
 		return(1);
 	}

 	return(0);
 }

 unsigned short eth_protocol(struct sk_buff *skb)
 {
 	return(eth_type_trans(skb, skb->dev));
 }
	/*
	* Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
	* James Leu (jleu@mindspring.net).
	* Copyright (C) 2001 by various other people who didn't put their name here.
	* Licensed under the GPL.
	*/

	#include "linux/kernel.h"
	#include "linux/netdevice.h"
	#include "linux/rtnetlink.h"
	#include "linux/skbuff.h"
	#include "linux/socket.h"
	#include "linux/spinlock.h"
	#include "linux/module.h"
	#include "linux/init.h"
	#include "linux/etherdevice.h"
	#include "linux/list.h"
	#include "linux/inetdevice.h"
	#include "linux/ctype.h"
	#include "linux/bootmem.h"
	#include "linux/ethtool.h"
	#include "linux/platform_device.h"
	#include "asm/uaccess.h"
	#include "user_util.h"
	#include "kern_util.h"
	#include "net_kern.h"
	#include "net_user.h"
	#include "mconsole_kern.h"
	#include "init.h"
	#include "irq_user.h"
	#include "irq_kern.h"

	static inline void set_ether_mac(struct net_device dev, unsigned char addr)
	{
	memcpy(dev->dev_addr, addr, ETH_ALEN);
	}

	#define DRIVER_NAME "uml-netdev"

	static DEFINE_SPINLOCK(opened_lock);
	static LIST_HEAD(opened);

	static int uml_net_rx(struct net_device *dev)
	{
	struct uml_net_private *lp = dev->priv;
	int pkt_len;
	struct sk_buff *skb;

	/* If we can't allocate memory, try again next round. */
	skb = dev_alloc_skb(dev->mtu);
	if (skb == NULL) {
	lp->stats.rx_dropped++;
	return 0;
	}

	skb->dev = dev;
	skb_put(skb, dev->mtu);
	skb_reset_mac_header(skb);
	pkt_len = (*lp->read)(lp->fd, &skb, lp);

	if (pkt_len > 0) {
	skb_trim(skb, pkt_len);
	skb->protocol = (*lp->protocol)(skb);
	netif_rx(skb);

	lp->stats.rx_bytes += skb->len;
	lp->stats.rx_packets++;
	return pkt_len;
	}

	kfree_skb(skb);
	return pkt_len;
	}

	static void uml_dev_close(struct work_struct *work)
	{
	struct uml_net_private *lp =
	container_of(work, struct uml_net_private, work);
	dev_close(lp->dev);
	}

	irqreturn_t uml_net_interrupt(int irq, void *dev_id)
	{
	struct net_device *dev = dev_id;
	struct uml_net_private *lp = dev->priv;
	int err;

	if(!netif_running(dev))
	return(IRQ_NONE);

	spin_lock(&lp->lock);
	while((err = uml_net_rx(dev)) > 0) ;
	if(err < 0) {
	printk(KERN_ERR
	"Device '%s' read returned %d, shutting it down\n",
	dev->name, err);
	/* dev_close can't be called in interrupt context, and takes
	* again lp->lock.
	* And dev_close() can be safely called multiple times on the
	* same device, since it tests for (dev->flags & IFF_UP). So
	* there's no harm in delaying the device shutdown.
	* Furthermore, the workqueue will not re-enqueue an already
	* enqueued work item. */
	schedule_work(&lp->work);
	goto out;
	}
	reactivate_fd(lp->fd, UM_ETH_IRQ);

	out:
	spin_unlock(&lp->lock);
	return IRQ_HANDLED;
	}

	static int uml_net_open(struct net_device *dev)
	{
	struct uml_net_private *lp = dev->priv;
	int err;

	if(lp->fd >= 0){
	err = -ENXIO;
	goto out;
	}

	lp->fd = (*lp->open)(&lp->user);
	if(lp->fd < 0){
	err = lp->fd;
	goto out;
	}

	err = um_request_irq(dev->irq, lp->fd, IRQ_READ, uml_net_interrupt,
	IRQF_DISABLED \| IRQF_SHARED, dev->name, dev);
	if(err != 0){
	printk(KERN_ERR "uml_net_open: failed to get irq(%d)\n", err);
	err = -ENETUNREACH;
	goto out_close;
	}

	lp->tl.data = (unsigned long) &lp->user;
	netif_start_queue(dev);

	/* clear buffer - it can happen that the host side of the interface
	* is full when we get here. In this case, new data is never queued,
	* SIGIOs never arrive, and the net never works.
	*/
	while((err = uml_net_rx(dev)) > 0) ;

	spin_lock(&opened_lock);
	list_add(&lp->list, &opened);
	spin_unlock(&opened_lock);

	return 0;
	out_close:
	if(lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
	lp->fd = -1;
	out:
	return err;
	}

	static int uml_net_close(struct net_device *dev)
	{
	struct uml_net_private *lp = dev->priv;

	netif_stop_queue(dev);

	free_irq(dev->irq, dev);
	if(lp->close != NULL)
	(*lp->close)(lp->fd, &lp->user);
	lp->fd = -1;

	spin_lock(&opened_lock);
	list_del(&lp->list);
	spin_unlock(&opened_lock);

	return 0;
	}

	static int uml_net_start_xmit(struct sk_buff skb, struct net_device dev)
	{
	struct uml_net_private *lp = dev->priv;
	unsigned long flags;
	int len;

	netif_stop_queue(dev);

	spin_lock_irqsave(&lp->lock, flags);

	len = (*lp->write)(lp->fd, &skb, lp);

	if(len == skb->len) {
	lp->stats.tx_packets++;
	lp->stats.tx_bytes += skb->len;
	dev->trans_start = jiffies;
	netif_start_queue(dev);

	/* this is normally done in the interrupt when tx finishes */
	netif_wake_queue(dev);
	}
	else if(len == 0){
	netif_start_queue(dev);
	lp->stats.tx_dropped++;
	}
	else {
	netif_start_queue(dev);
	printk(KERN_ERR "uml_net_start_xmit: failed(%d)\n", len);
	}

	spin_unlock_irqrestore(&lp->lock, flags);

	dev_kfree_skb(skb);

	return 0;
	}

	static struct net_device_stats uml_net_get_stats(struct net_device dev)
	{
	struct uml_net_private *lp = dev->priv;
	return &lp->stats;
	}

	static void uml_net_set_multicast_list(struct net_device *dev)
	{
	if (dev->flags & IFF_PROMISC) return;
	else if (dev->mc_count) dev->flags \|= IFF_ALLMULTI;
	else dev->flags &= ~IFF_ALLMULTI;
	}

	static void uml_net_tx_timeout(struct net_device *dev)
	{
	dev->trans_start = jiffies;
	netif_wake_queue(dev);
	}

	static int uml_net_set_mac(struct net_device dev, void addr)
	{
	struct uml_net_private *lp = dev->priv;
	struct sockaddr *hwaddr = addr;

	spin_lock_irq(&lp->lock);
	set_ether_mac(dev, hwaddr->sa_data);
	spin_unlock_irq(&lp->lock);

	return 0;
	}

	static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
	{
	struct uml_net_private *lp = dev->priv;
	int err = 0;

	spin_lock_irq(&lp->lock);

	new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
	if(new_mtu < 0){
	err = new_mtu;
	goto out;
	}

	dev->mtu = new_mtu;

	out:
	spin_unlock_irq(&lp->lock);
	return err;
	}

	static void uml_net_get_drvinfo(struct net_device *dev,
	struct ethtool_drvinfo *info)
	{
	strcpy(info->driver, DRIVER_NAME);
	strcpy(info->version, "42");
	}

	static struct ethtool_ops uml_net_ethtool_ops = {
	.get_drvinfo = uml_net_get_drvinfo,
	.get_link = ethtool_op_get_link,
	};

	void uml_net_user_timer_expire(unsigned long _conn)
	{
	#ifdef undef
	struct connection conn = (struct connection )_conn;

	dprintk(KERN_INFO "uml_net_user_timer_expire [%p]\n", conn);
	do_connect(conn);
	#endif
	}

	static void setup_etheraddr(char str, unsigned char addr)
	{
	char *end;
	int i;

	if(str == NULL)
	goto random;

	for(i=0;i<6;i++){
	addr[i] = simple_strtoul(str, &end, 16);
	if((end == str) \|\|
	((end != ':') && (end != ',') && (*end != '\0'))){
	printk(KERN_ERR
	"setup_etheraddr: failed to parse '%s' "
	"as an ethernet address\n", str);
	goto random;
	}
	str = end + 1;
	}
	if(addr[0] & 1){
	printk(KERN_ERR
	"Attempt to assign a broadcast ethernet address to a "
	"device disallowed\n");
	goto random;
	}
	return;

	random:
	random_ether_addr(addr);
	}

	static DEFINE_SPINLOCK(devices_lock);
	static LIST_HEAD(devices);

	static struct platform_driver uml_net_driver = {
	.driver = {
	.name = DRIVER_NAME,
	},
	};
	static int driver_registered;

	static int eth_configure(int n, void init, char mac,
	struct transport *transport)
	{
	struct uml_net *device;
	struct net_device *dev;
	struct uml_net_private *lp;
	int save, err, size;

	size = transport->private_size + sizeof(struct uml_net_private) +
	sizeof(((struct uml_net_private *) 0)->user);

	device = kzalloc(sizeof(*device), GFP_KERNEL);
	if (device == NULL) {
	printk(KERN_ERR "eth_configure failed to allocate uml_net\n");
	return(1);
	}

	INIT_LIST_HEAD(&device->list);
	device->index = n;

	spin_lock(&devices_lock);
	list_add(&device->list, &devices);
	spin_unlock(&devices_lock);

	setup_etheraddr(mac, device->mac);

	printk(KERN_INFO "Netdevice %d ", n);
	printk("(%02x:%02x:%02x:%02x:%02x:%02x) ",
	device->mac[0], device->mac[1],
	device->mac[2], device->mac[3],
	device->mac[4], device->mac[5]);
	printk(": ");
	dev = alloc_etherdev(size);
	if (dev == NULL) {
	printk(KERN_ERR "eth_configure: failed to allocate device\n");
	return 1;
	}

	lp = dev->priv;
	/* This points to the transport private data. It's still clear, but we
	* must memset it to 0 now. Let's help the drivers. */
	memset(lp, 0, size);
	INIT_WORK(&lp->work, uml_dev_close);

	/* sysfs register */
	if (!driver_registered) {
	platform_driver_register(&uml_net_driver);
	driver_registered = 1;
	}
	device->pdev.id = n;
	device->pdev.name = DRIVER_NAME;
	platform_device_register(&device->pdev);
	SET_NETDEV_DEV(dev,&device->pdev.dev);

	/* If this name ends up conflicting with an existing registered
	* netdevice, that is OK, register_netdev{,ice}() will notice this
	* and fail.
	*/
	snprintf(dev->name, sizeof(dev->name), "eth%d", n);
	device->dev = dev;

	(*transport->kern->init)(dev, init);

	dev->mtu = transport->user->max_packet;
	dev->open = uml_net_open;
	dev->hard_start_xmit = uml_net_start_xmit;
	dev->stop = uml_net_close;
	dev->get_stats = uml_net_get_stats;
	dev->set_multicast_list = uml_net_set_multicast_list;
	dev->tx_timeout = uml_net_tx_timeout;
	dev->set_mac_address = uml_net_set_mac;
	dev->change_mtu = uml_net_change_mtu;
	dev->ethtool_ops = &uml_net_ethtool_ops;
	dev->watchdog_timeo = (HZ >> 1);
	dev->irq = UM_ETH_IRQ;

	rtnl_lock();
	err = register_netdevice(dev);
	rtnl_unlock();
	if (err) {
	device->dev = NULL;
	/* XXX: should we call ->remove() here? */
	free_netdev(dev);
	return 1;
	}

	/* lp.user is the first four bytes of the transport data, which
	* has already been initialized. This structure assignment will
	* overwrite that, so we make sure that .user gets overwritten with
	* what it already has.
	*/
	save = lp->user[0];
	*lp = ((struct uml_net_private)
	{ .list = LIST_HEAD_INIT(lp->list),
	.dev = dev,
	.fd = -1,
	.mac = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
	.protocol = transport->kern->protocol,
	.open = transport->user->open,
	.close = transport->user->close,
	.remove = transport->user->remove,
	.read = transport->kern->read,
	.write = transport->kern->write,
	.add_address = transport->user->add_address,
	.delete_address = transport->user->delete_address,
	.set_mtu = transport->user->set_mtu,
	.user = { save } });

	init_timer(&lp->tl);
	spin_lock_init(&lp->lock);
	lp->tl.function = uml_net_user_timer_expire;
	memcpy(lp->mac, device->mac, sizeof(lp->mac));

	if (transport->user->init)
	(*transport->user->init)(&lp->user, dev);

	set_ether_mac(dev, device->mac);

	return 0;
	}

	static struct uml_net *find_device(int n)
	{
	struct uml_net *device;
	struct list_head *ele;

	spin_lock(&devices_lock);
	list_for_each(ele, &devices){
	device = list_entry(ele, struct uml_net, list);
	if(device->index == n)
	goto out;
	}
	device = NULL;
	out:
	spin_unlock(&devices_lock);
	return device;
	}

	static int eth_parse(char str, int index_out, char **str_out,
	char **error_out)
	{
	char *end;
	int n, err = -EINVAL;;

	n = simple_strtoul(str, &end, 0);
	if(end == str){
	*error_out = "Bad device number";
	return err;
	}

	str = end;
	if(*str != '='){
	*error_out = "Expected '=' after device number";
	return err;
	}

	str++;
	if(find_device(n)){
	*error_out = "Device already configured";
	return err;
	}

	*index_out = n;
	*str_out = str;
	return 0;
	}

	struct eth_init {
	struct list_head list;
	char *init;
	int index;
	};

	static DEFINE_SPINLOCK(transports_lock);
	static LIST_HEAD(transports);

	/* Filled in during early boot */
	static LIST_HEAD(eth_cmd_line);

	static int check_transport(struct transport transport, char eth, int n,
	void init_out, char mac_out)
	{
	int len;

	len = strlen(transport->name);
	if(strncmp(eth, transport->name, len))
	return 0;

	eth += len;
	if(*eth == ',')
	eth++;
	else if(*eth != '\0')
	return 0;

	*init_out = kmalloc(transport->setup_size, GFP_KERNEL);
	if(*init_out == NULL)
	return 1;

	if(!transport->setup(eth, mac_out, *init_out)){
	kfree(*init_out);
	*init_out = NULL;
	}
	return 1;
	}

	void register_transport(struct transport *new)
	{
	struct list_head ele, next;
	struct eth_init *eth;
	void *init;
	char *mac = NULL;
	int match;

	spin_lock(&transports_lock);
	BUG_ON(!list_empty(&new->list));
	list_add(&new->list, &transports);
	spin_unlock(&transports_lock);

	list_for_each_safe(ele, next, &eth_cmd_line){
	eth = list_entry(ele, struct eth_init, list);
	match = check_transport(new, eth->init, eth->index, &init,
	&mac);
	if(!match)
	continue;
	else if(init != NULL){
	eth_configure(eth->index, init, mac, new);
	kfree(init);
	}
	list_del(&eth->list);
	}
	}

	static int eth_setup_common(char *str, int index)
	{
	struct list_head *ele;
	struct transport *transport;
	void *init;
	char *mac = NULL;
	int found = 0;

	spin_lock(&transports_lock);
	list_for_each(ele, &transports){
	transport = list_entry(ele, struct transport, list);
	if(!check_transport(transport, str, index, &init, &mac))
	continue;
	if(init != NULL){
	eth_configure(index, init, mac, transport);
	kfree(init);
	}
	found = 1;
	break;
	}

	spin_unlock(&transports_lock);
	return found;
	}

	static int eth_setup(char *str)
	{
	struct eth_init *new;
	char *error;
	int n, err;

	err = eth_parse(str, &n, &str, &error);
	if(err){
	printk(KERN_ERR "eth_setup - Couldn't parse '%s' : %s\n",
	str, error);
	return 1;
	}

	new = alloc_bootmem(sizeof(*new));
	if (new == NULL){
	printk("eth_init : alloc_bootmem failed\n");
	return 1;
	}

	INIT_LIST_HEAD(&new->list);
	new->index = n;
	new->init = str;

	list_add_tail(&new->list, &eth_cmd_line);
	return 1;
	}

	__setup("eth", eth_setup);
	__uml_help(eth_setup,
	"eth[0-9]+=<transport>,<options>\n"
	" Configure a network device.\n\n"
	);

	static int net_config(char str, char *error_out)
	{
	int n, err;

	err = eth_parse(str, &n, &str, error_out);
	if(err)
	return err;

	/* This string is broken up and the pieces used by the underlying
	* driver. So, it is freed only if eth_setup_common fails.
	*/
	str = kstrdup(str, GFP_KERNEL);
	if(str == NULL){
	*error_out = "net_config failed to strdup string";
	return -ENOMEM;
	}
	err = !eth_setup_common(str, n);
	if(err)
	kfree(str);
	return(err);
	}

	static int net_id(char *str, int start_out, int *end_out)
	{
	char *end;
	int n;

	n = simple_strtoul(*str, &end, 0);
	if((end != '\0') \|\| (end == str))
	return -1;

	*start_out = n;
	*end_out = n;
	*str = end;
	return n;
	}

	static int net_remove(int n, char **error_out)
	{
	struct uml_net *device;
	struct net_device *dev;
	struct uml_net_private *lp;

	device = find_device(n);
	if(device == NULL)
	return -ENODEV;

	dev = device->dev;
	lp = dev->priv;
	if(lp->fd > 0)
	return -EBUSY;
	if(lp->remove != NULL) (*lp->remove)(&lp->user);
	unregister_netdev(dev);
	platform_device_unregister(&device->pdev);

	list_del(&device->list);
	kfree(device);
	free_netdev(dev);
	return 0;
	}

	static struct mc_device net_mc = {
	.list = LIST_HEAD_INIT(net_mc.list),
	.name = "eth",
	.config = net_config,
	.get_config = NULL,
	.id = net_id,
	.remove = net_remove,
	};

	static int uml_inetaddr_event(struct notifier_block *this, unsigned long event,
	void *ptr)
	{
	struct in_ifaddr *ifa = ptr;
	struct net_device *dev = ifa->ifa_dev->dev;
	struct uml_net_private *lp;
	void (proc)(unsigned char , unsigned char , void );
	unsigned char addr_buf[4], netmask_buf[4];

	if(dev->open != uml_net_open)
	return NOTIFY_DONE;

	lp = dev->priv;

	proc = NULL;
	switch (event){
	case NETDEV_UP:
	proc = lp->add_address;
	break;
	case NETDEV_DOWN:
	proc = lp->delete_address;
	break;
	}
	if(proc != NULL){
	memcpy(addr_buf, &ifa->ifa_address, sizeof(addr_buf));
	memcpy(netmask_buf, &ifa->ifa_mask, sizeof(netmask_buf));
	(*proc)(addr_buf, netmask_buf, &lp->user);
	}
	return NOTIFY_DONE;
	}

	/* uml_net_init shouldn't be called twice on two CPUs at the same time */
	struct notifier_block uml_inetaddr_notifier = {
	.notifier_call = uml_inetaddr_event,
	};

	static int uml_net_init(void)
	{
	struct list_head *ele;
	struct uml_net_private *lp;
	struct in_device *ip;
	struct in_ifaddr *in;

	mconsole_register_dev(&net_mc);
	register_inetaddr_notifier(&uml_inetaddr_notifier);

	/* Devices may have been opened already, so the uml_inetaddr_notifier
	* didn't get a chance to run for them. This fakes it so that
	* addresses which have already been set up get handled properly.
	*/
	spin_lock(&opened_lock);
	list_for_each(ele, &opened){
	lp = list_entry(ele, struct uml_net_private, list);
	ip = lp->dev->ip_ptr;
	if(ip == NULL)
	continue;
	in = ip->ifa_list;
	while(in != NULL){
	uml_inetaddr_event(NULL, NETDEV_UP, in);
	in = in->ifa_next;
	}
	}
	spin_unlock(&opened_lock);

	return 0;
	}

	__initcall(uml_net_init);

	static void close_devices(void)
	{
	struct list_head *ele;
	struct uml_net_private *lp;

	spin_lock(&opened_lock);
	list_for_each(ele, &opened){
	lp = list_entry(ele, struct uml_net_private, list);
	free_irq(lp->dev->irq, lp->dev);
	if((lp->close != NULL) && (lp->fd >= 0))
	(*lp->close)(lp->fd, &lp->user);
	if(lp->remove != NULL)
	(*lp->remove)(&lp->user);
	}
	spin_unlock(&opened_lock);
	}

	__uml_exitcall(close_devices);

	struct sk_buff ether_adjust_skb(struct sk_buff skb, int extra)
	{
	if((skb != NULL) && (skb_tailroom(skb) < extra)){
	struct sk_buff *skb2;

	skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
	dev_kfree_skb(skb);
	skb = skb2;
	}
	if(skb != NULL) skb_put(skb, extra);
	return(skb);
	}

	void iter_addresses(void d, void (cb)(unsigned char , unsigned char ,
	void *),
	void *arg)
	{
	struct net_device *dev = d;
	struct in_device *ip = dev->ip_ptr;
	struct in_ifaddr *in;
	unsigned char address[4], netmask[4];

	if(ip == NULL) return;
	in = ip->ifa_list;
	while(in != NULL){
	memcpy(address, &in->ifa_address, sizeof(address));
	memcpy(netmask, &in->ifa_mask, sizeof(netmask));
	(*cb)(address, netmask, arg);
	in = in->ifa_next;
	}
	}

	int dev_netmask(void d, void m)
	{
	struct net_device *dev = d;
	struct in_device *ip = dev->ip_ptr;
	struct in_ifaddr *in;
	__be32 *mask_out = m;

	if(ip == NULL)
	return(1);

	in = ip->ifa_list;
	if(in == NULL)
	return(1);

	*mask_out = in->ifa_mask;
	return(0);
	}

	void get_output_buffer(int len_out)
	{
	void *ret;

	ret = (void *) __get_free_pages(GFP_KERNEL, 0);
	if(ret) *len_out = PAGE_SIZE;
	else *len_out = 0;
	return ret;
	}

	void free_output_buffer(void *buffer)
	{
	free_pages((unsigned long) buffer, 0);
	}

	int tap_setup_common(char str, char type, char dev_name, char mac_out,
	char **gate_addr)
	{
	char *remain;

	remain = split_if_spec(str, dev_name, mac_out, gate_addr, NULL);
	if(remain != NULL){
	printk("tap_setup_common - Extra garbage on specification : "
	"'%s'\n", remain);
	return(1);
	}

	return(0);
	}

	unsigned short eth_protocol(struct sk_buff *skb)
	{
	return(eth_type_trans(skb, skb->dev));
	}