arch/ia64/hp/sim/simeth.c - kernel/msm-4.9 - Gitiles

 /*
  * Simulated Ethernet Driver
  *
  * Copyright (C) 1999-2001, 2003 Hewlett-Packard Co
  *	Stephane Eranian <eranian@hpl.hp.com>
  */
 #include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/types.h>
 #include <linux/in.h>
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/interrupt.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/inetdevice.h>
 #include <linux/if_ether.h>
 #include <linux/if_arp.h>
 #include <linux/skbuff.h>
 #include <linux/notifier.h>
 #include <linux/bitops.h>
 #include <asm/system.h>
 #include <asm/irq.h>

 #define SIMETH_RECV_MAX	10

 /*
  * Maximum possible received frame for Ethernet.
  * We preallocate an sk_buff of that size to avoid costly
  * memcpy for temporary buffer into sk_buff. We do basically
  * what's done in other drivers, like eepro with a ring.
  * The difference is, of course, that we don't have real DMA !!!
  */
 #define SIMETH_FRAME_SIZE	ETH_FRAME_LEN


 #define SSC_NETDEV_PROBE		100
 #define SSC_NETDEV_SEND			101
 #define SSC_NETDEV_RECV			102
 #define SSC_NETDEV_ATTACH		103
 #define SSC_NETDEV_DETACH		104

 #define NETWORK_INTR			8

 struct simeth_local {
 	struct net_device_stats stats;
 	int 			simfd;	 /* descriptor in the simulator */
 };

 static int simeth_probe1(void);
 static int simeth_open(struct net_device *dev);
 static int simeth_close(struct net_device *dev);
 static int simeth_tx(struct sk_buff *skb, struct net_device *dev);
 static int simeth_rx(struct net_device *dev);
 static struct net_device_stats *simeth_get_stats(struct net_device *dev);
 static irqreturn_t simeth_interrupt(int irq, void *dev_id, struct pt_regs * regs);
 static void set_multicast_list(struct net_device *dev);
 static int simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr);

 static char *simeth_version="0.3";

 /*
  * This variable is used to establish a mapping between the Linux/ia64 kernel
  * and the host linux kernel.
  *
  * As of today, we support only one card, even though most of the code
  * is ready for many more. The mapping is then:
  *	linux/ia64 -> linux/x86
  * 	   eth0    -> eth1
  *
  * In the future, we some string operations, we could easily support up
  * to 10 cards (0-9).
  *
  * The default mapping can be changed on the kernel command line by
  * specifying simeth=ethX (or whatever string you want).
  */
 static char *simeth_device="eth0";	 /* default host interface to use */


 static volatile unsigned int card_count; /* how many cards "found" so far */
 static int simeth_debug;		/* set to 1 to get debug information */

 /*
  * Used to catch IFF_UP & IFF_DOWN events
  */
 static struct notifier_block simeth_dev_notifier = {
 	simeth_device_event,
 	0
 };


 /*
  * Function used when using a kernel command line option.
  *
  * Format: simeth=interface_name (like eth0)
  */
 static int __init
 simeth_setup(char *str)
 {
 	simeth_device = str;
 	return 1;
 }

 __setup("simeth=", simeth_setup);

 /*
  * Function used to probe for simeth devices when not installed
  * as a loadable module
  */

 int __init
 simeth_probe (void)
 {
 	int r;

 	printk(KERN_INFO "simeth: v%s\n", simeth_version);

 	r = simeth_probe1();

 	if (r == 0) register_netdevice_notifier(&simeth_dev_notifier);

 	return r;
 }

 extern long ia64_ssc (long, long, long, long, int);
 extern void ia64_ssc_connect_irq (long intr, long irq);

 static inline int
 netdev_probe(char *name, unsigned char *ether)
 {
 	return ia64_ssc(__pa(name), __pa(ether), 0,0, SSC_NETDEV_PROBE);
 }


 static inline int
 netdev_connect(int irq)
 {
 	/* XXX Fix me
 	 * this does not support multiple cards
 	 * also no return value
 	 */
 	ia64_ssc_connect_irq(NETWORK_INTR, irq);
 	return 0;
 }

 static inline int
 netdev_attach(int fd, int irq, unsigned int ipaddr)
 {
 	/* this puts the host interface in the right mode (start interrupting) */
 	return ia64_ssc(fd, ipaddr, 0,0, SSC_NETDEV_ATTACH);
 }


 static inline int
 netdev_detach(int fd)
 {
 	/*
 	 * inactivate the host interface (don't interrupt anymore) */
 	return ia64_ssc(fd, 0,0,0, SSC_NETDEV_DETACH);
 }

 static inline int
 netdev_send(int fd, unsigned char *buf, unsigned int len)
 {
 	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_SEND);
 }

 static inline int
 netdev_read(int fd, unsigned char *buf, unsigned int len)
 {
 	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_RECV);
 }

 /*
  * Function shared with module code, so cannot be in init section
  *
  * So far this function "detects" only one card (test_&_set) but could
  * be extended easily.
  *
  * Return:
  * 	- -ENODEV is no device found
  *	- -ENOMEM is no more memory
  *	- 0 otherwise
  */
 static int
 simeth_probe1(void)
 {
 	unsigned char mac_addr[ETH_ALEN];
 	struct simeth_local *local;
 	struct net_device *dev;
 	int fd, i, err, rc;

 	/*
 	 * XXX Fix me
 	 * let's support just one card for now
 	 */
 	if (test_and_set_bit(0, &card_count))
 		return -ENODEV;

 	/*
 	 * check with the simulator for the device
 	 */
 	fd = netdev_probe(simeth_device, mac_addr);
 	if (fd == -1)
 		return -ENODEV;

 	dev = alloc_etherdev(sizeof(struct simeth_local));
 	if (!dev)
 		return -ENOMEM;

 	memcpy(dev->dev_addr, mac_addr, sizeof(mac_addr));

 	local = dev->priv;
 	local->simfd = fd; /* keep track of underlying file descriptor */

 	dev->open		= simeth_open;
 	dev->stop		= simeth_close;
 	dev->hard_start_xmit	= simeth_tx;
 	dev->get_stats		= simeth_get_stats;
 	dev->set_multicast_list = set_multicast_list; /* no yet used */

 	err = register_netdev(dev);
 	if (err) {
 		free_netdev(dev);
 		return err;
 	}

 	if ((rc = assign_irq_vector(AUTO_ASSIGN)) < 0)
 		panic("%s: out of interrupt vectors!\n", __FUNCTION__);
 	dev->irq = rc;

 	/*
 	 * attach the interrupt in the simulator, this does enable interrupts
 	 * until a netdev_attach() is called
 	 */
 	netdev_connect(dev->irq);

 	printk(KERN_INFO "%s: hosteth=%s simfd=%d, HwAddr",
 	       dev->name, simeth_device, local->simfd);
 	for(i = 0; i < ETH_ALEN; i++) {
 		printk(" %2.2x", dev->dev_addr[i]);
 	}
 	printk(", IRQ %d\n", dev->irq);

 	return 0;
 }

 /*
  * actually binds the device to an interrupt vector
  */
 static int
 simeth_open(struct net_device *dev)
 {
 	if (request_irq(dev->irq, simeth_interrupt, 0, "simeth", dev)) {
 		printk(KERN_WARNING "simeth: unable to get IRQ %d.\n", dev->irq);
 		return -EAGAIN;
 	}

 	netif_start_queue(dev);

 	return 0;
 }

 /* copied from lapbether.c */
 static __inline__ int dev_is_ethdev(struct net_device *dev)
 {
        return ( dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5));
 }


 /*
  * Handler for IFF_UP or IFF_DOWN
  *
  * The reason for that is that we don't want to be interrupted when the
  * interface is down. There is no way to unconnect in the simualtor. Instead
  * we use this function to shutdown packet processing in the frame filter
  * in the simulator. Thus no interrupts are generated
  *
  *
  * That's also the place where we pass the IP address of this device to the
  * simulator so that that we can start filtering packets for it
  *
  * There may be a better way of doing this, but I don't know which yet.
  */
 static int
 simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr)
 {
 	struct net_device *dev = ptr;
 	struct simeth_local *local;
 	struct in_device *in_dev;
 	struct in_ifaddr **ifap = NULL;
 	struct in_ifaddr *ifa = NULL;
 	int r;


 	if ( ! dev ) {
 		printk(KERN_WARNING "simeth_device_event dev=0\n");
 		return NOTIFY_DONE;
 	}

 	if ( event != NETDEV_UP && event != NETDEV_DOWN ) return NOTIFY_DONE;

 	/*
 	 * Check whether or not it's for an ethernet device
 	 *
 	 * XXX Fixme: This works only as long as we support one
 	 * type of ethernet device.
 	 */
 	if ( !dev_is_ethdev(dev) ) return NOTIFY_DONE;

 	if ((in_dev=dev->ip_ptr) != NULL) {
 		for (ifap=&in_dev->ifa_list; (ifa=*ifap) != NULL; ifap=&ifa->ifa_next)
 			if (strcmp(dev->name, ifa->ifa_label) == 0) break;
 	}
 	if ( ifa == NULL ) {
 		printk(KERN_ERR "simeth_open: can't find device %s's ifa\n", dev->name);
 		return NOTIFY_DONE;
 	}

 	printk(KERN_INFO "simeth_device_event: %s ipaddr=0x%x\n",
 	       dev->name, htonl(ifa->ifa_local));

 	/*
 	 * XXX Fix me
 	 * if the device was up, and we're simply reconfiguring it, not sure
 	 * we get DOWN then UP.
 	 */

 	local = dev->priv;
 	/* now do it for real */
 	r = event == NETDEV_UP ?
 		netdev_attach(local->simfd, dev->irq, htonl(ifa->ifa_local)):
 		netdev_detach(local->simfd);

 	printk(KERN_INFO "simeth: netdev_attach/detach: event=%s ->%d\n",
 	       event == NETDEV_UP ? "attach":"detach", r);

 	return NOTIFY_DONE;
 }

 static int
 simeth_close(struct net_device *dev)
 {
 	netif_stop_queue(dev);

 	free_irq(dev->irq, dev);

 	return 0;
 }

 /*
  * Only used for debug
  */
 static void
 frame_print(unsigned char *from, unsigned char *frame, int len)
 {
 	int i;

 	printk("%s: (%d) %02x", from, len, frame[0] & 0xff);
 	for(i=1; i < 6; i++ ) {
 		printk(":%02x", frame[i] &0xff);
 	}
 	printk(" %2x", frame[6] &0xff);
 	for(i=7; i < 12; i++ ) {
 		printk(":%02x", frame[i] &0xff);
 	}
 	printk(" [%02x%02x]\n", frame[12], frame[13]);

 	for(i=14; i < len; i++ ) {
 		printk("%02x ", frame[i] &0xff);
 		if ( (i%10)==0) printk("\n");
 	}
 	printk("\n");
 }


 /*
  * Function used to transmit of frame, very last one on the path before
  * going to the simulator.
  */
 static int
 simeth_tx(struct sk_buff *skb, struct net_device *dev)
 {
 	struct simeth_local *local = dev->priv;

 #if 0
 	/* ensure we have at least ETH_ZLEN bytes (min frame size) */
 	unsigned int length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
 	/* Where do the extra padding bytes comes from inthe skbuff ? */
 #else
 	/* the real driver in the host system is going to take care of that
 	 * or maybe it's the NIC itself.
 	 */
 	unsigned int length = skb->len;
 #endif

 	local->stats.tx_bytes += skb->len;
 	local->stats.tx_packets++;


 	if (simeth_debug > 5) frame_print("simeth_tx", skb->data, length);

 	netdev_send(local->simfd, skb->data, length);

 	/*
 	 * we are synchronous on write, so we don't simulate a
 	 * trasnmit complete interrupt, thus we don't need to arm a tx
 	 */

 	dev_kfree_skb(skb);
 	return 0;
 }

 static inline struct sk_buff *
 make_new_skb(struct net_device *dev)
 {
 	struct sk_buff *nskb;

 	/*
 	 * The +2 is used to make sure that the IP header is nicely
 	 * aligned (on 4byte boundary I assume 14+2=16)
 	 */
 	nskb = dev_alloc_skb(SIMETH_FRAME_SIZE + 2);
 	if ( nskb == NULL ) {
 		printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
 		return NULL;
 	}
 	nskb->dev = dev;

 	skb_reserve(nskb, 2);	/* Align IP on 16 byte boundaries */

 	skb_put(nskb,SIMETH_FRAME_SIZE);

 	return nskb;
 }

 /*
  * called from interrupt handler to process a received frame
  */
 static int
 simeth_rx(struct net_device *dev)
 {
 	struct simeth_local	*local;
 	struct sk_buff		*skb;
 	int			len;
 	int			rcv_count = SIMETH_RECV_MAX;

 	local = dev->priv;
 	/*
 	 * the loop concept has been borrowed from other drivers
 	 * looks to me like it's a throttling thing to avoid pushing to many
 	 * packets at one time into the stack. Making sure we can process them
 	 * upstream and make forward progress overall
 	 */
 	do {
 		if ( (skb=make_new_skb(dev)) == NULL ) {
 			printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
 			local->stats.rx_dropped++;
 			return 0;
 		}
 		/*
 		 * Read only one frame at a time
 		 */
 		len = netdev_read(local->simfd, skb->data, SIMETH_FRAME_SIZE);
 		if ( len == 0 ) {
 			if ( simeth_debug > 0 ) printk(KERN_WARNING "%s: count=%d netdev_read=0\n",
 						       dev->name, SIMETH_RECV_MAX-rcv_count);
 			break;
 		}
 #if 0
 		/*
 		 * XXX Fix me
 		 * Should really do a csum+copy here
 		 */
 		memcpy(skb->data, frame, len);
 #endif
 		skb->protocol = eth_type_trans(skb, dev);

 		if ( simeth_debug > 6 ) frame_print("simeth_rx", skb->data, len);

 		/*
 		 * push the packet up & trigger software interrupt
 		 */
 		netif_rx(skb);

 		local->stats.rx_packets++;
 		local->stats.rx_bytes += len;

 	} while ( --rcv_count );

 	return len; /* 0 = nothing left to read, otherwise, we can try again */
 }

 /*
  * Interrupt handler (Yes, we can do it too !!!)
  */
 static irqreturn_t
 simeth_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 {
 	struct net_device *dev = dev_id;

 	if ( dev == NULL ) {
 		printk(KERN_WARNING "simeth: irq %d for unknown device\n", irq);
 		return IRQ_NONE;
 	}

 	/*
 	 * very simple loop because we get interrupts only when receiving
 	 */
 	while (simeth_rx(dev));
 	return IRQ_HANDLED;
 }

 static struct net_device_stats *
 simeth_get_stats(struct net_device *dev)
 {
 	struct simeth_local *local = dev->priv;

 	return &local->stats;
 }

 /* fake multicast ability */
 static void
 set_multicast_list(struct net_device *dev)
 {
 	printk(KERN_WARNING "%s: set_multicast_list called\n", dev->name);
 }

 __initcall(simeth_probe);
	/*
	* Simulated Ethernet Driver
	*
	* Copyright (C) 1999-2001, 2003 Hewlett-Packard Co
	* Stephane Eranian <eranian@hpl.hp.com>
	*/
	#include <linux/config.h>
	#include <linux/kernel.h>
	#include <linux/sched.h>
	#include <linux/types.h>
	#include <linux/in.h>
	#include <linux/string.h>
	#include <linux/init.h>
	#include <linux/errno.h>
	#include <linux/interrupt.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/inetdevice.h>
	#include <linux/if_ether.h>
	#include <linux/if_arp.h>
	#include <linux/skbuff.h>
	#include <linux/notifier.h>
	#include <linux/bitops.h>
	#include <asm/system.h>
	#include <asm/irq.h>

	#define SIMETH_RECV_MAX 10

	/*
	* Maximum possible received frame for Ethernet.
	* We preallocate an sk_buff of that size to avoid costly
	* memcpy for temporary buffer into sk_buff. We do basically
	* what's done in other drivers, like eepro with a ring.
	* The difference is, of course, that we don't have real DMA !!!
	*/
	#define SIMETH_FRAME_SIZE ETH_FRAME_LEN


	#define SSC_NETDEV_PROBE 100
	#define SSC_NETDEV_SEND 101
	#define SSC_NETDEV_RECV 102
	#define SSC_NETDEV_ATTACH 103
	#define SSC_NETDEV_DETACH 104

	#define NETWORK_INTR 8

	struct simeth_local {
	struct net_device_stats stats;
	int simfd; /* descriptor in the simulator */
	};

	static int simeth_probe1(void);
	static int simeth_open(struct net_device *dev);
	static int simeth_close(struct net_device *dev);
	static int simeth_tx(struct sk_buff skb, struct net_device dev);
	static int simeth_rx(struct net_device *dev);
	static struct net_device_stats simeth_get_stats(struct net_device dev);
	static irqreturn_t simeth_interrupt(int irq, void dev_id, struct pt_regs regs);
	static void set_multicast_list(struct net_device *dev);
	static int simeth_device_event(struct notifier_block this,unsigned long event, void ptr);

	static char *simeth_version="0.3";

	/*
	* This variable is used to establish a mapping between the Linux/ia64 kernel
	* and the host linux kernel.
	*
	* As of today, we support only one card, even though most of the code
	* is ready for many more. The mapping is then:
	* linux/ia64 -> linux/x86
	* eth0 -> eth1
	*
	* In the future, we some string operations, we could easily support up
	* to 10 cards (0-9).
	*
	* The default mapping can be changed on the kernel command line by
	* specifying simeth=ethX (or whatever string you want).
	*/
	static char simeth_device="eth0"; / default host interface to use */



	static volatile unsigned int card_count; /* how many cards "found" so far */
	static int simeth_debug; /* set to 1 to get debug information */

	/*
	* Used to catch IFF_UP & IFF_DOWN events
	*/
	static struct notifier_block simeth_dev_notifier = {
	simeth_device_event,
	0
	};


	/*
	* Function used when using a kernel command line option.
	*
	* Format: simeth=interface_name (like eth0)
	*/
	static int __init
	simeth_setup(char *str)
	{
	simeth_device = str;
	return 1;
	}

	__setup("simeth=", simeth_setup);

	/*
	* Function used to probe for simeth devices when not installed
	* as a loadable module
	*/

	int __init
	simeth_probe (void)
	{
	int r;

	printk(KERN_INFO "simeth: v%s\n", simeth_version);

	r = simeth_probe1();

	if (r == 0) register_netdevice_notifier(&simeth_dev_notifier);

	return r;
	}

	extern long ia64_ssc (long, long, long, long, int);
	extern void ia64_ssc_connect_irq (long intr, long irq);

	static inline int
	netdev_probe(char name, unsigned char ether)
	{
	return ia64_ssc(__pa(name), __pa(ether), 0,0, SSC_NETDEV_PROBE);
	}


	static inline int
	netdev_connect(int irq)
	{
	/* XXX Fix me
	* this does not support multiple cards
	* also no return value
	*/
	ia64_ssc_connect_irq(NETWORK_INTR, irq);
	return 0;
	}

	static inline int
	netdev_attach(int fd, int irq, unsigned int ipaddr)
	{
	/* this puts the host interface in the right mode (start interrupting) */
	return ia64_ssc(fd, ipaddr, 0,0, SSC_NETDEV_ATTACH);
	}


	static inline int
	netdev_detach(int fd)
	{
	/*
	* inactivate the host interface (don't interrupt anymore) */
	return ia64_ssc(fd, 0,0,0, SSC_NETDEV_DETACH);
	}

	static inline int
	netdev_send(int fd, unsigned char *buf, unsigned int len)
	{
	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_SEND);
	}

	static inline int
	netdev_read(int fd, unsigned char *buf, unsigned int len)
	{
	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_RECV);
	}

	/*
	* Function shared with module code, so cannot be in init section
	*
	* So far this function "detects" only one card (test_&_set) but could
	* be extended easily.
	*
	* Return:
	* - -ENODEV is no device found
	* - -ENOMEM is no more memory
	* - 0 otherwise
	*/
	static int
	simeth_probe1(void)
	{
	unsigned char mac_addr[ETH_ALEN];
	struct simeth_local *local;
	struct net_device *dev;
	int fd, i, err, rc;

	/*
	* XXX Fix me
	* let's support just one card for now
	*/
	if (test_and_set_bit(0, &card_count))
	return -ENODEV;

	/*
	* check with the simulator for the device
	*/
	fd = netdev_probe(simeth_device, mac_addr);
	if (fd == -1)
	return -ENODEV;

	dev = alloc_etherdev(sizeof(struct simeth_local));
	if (!dev)
	return -ENOMEM;

	memcpy(dev->dev_addr, mac_addr, sizeof(mac_addr));

	local = dev->priv;
	local->simfd = fd; /* keep track of underlying file descriptor */

	dev->open = simeth_open;
	dev->stop = simeth_close;
	dev->hard_start_xmit = simeth_tx;
	dev->get_stats = simeth_get_stats;
	dev->set_multicast_list = set_multicast_list; /* no yet used */

	err = register_netdev(dev);
	if (err) {
	free_netdev(dev);
	return err;
	}

	if ((rc = assign_irq_vector(AUTO_ASSIGN)) < 0)
	panic("%s: out of interrupt vectors!\n", __FUNCTION__);
	dev->irq = rc;

	/*
	* attach the interrupt in the simulator, this does enable interrupts
	* until a netdev_attach() is called
	*/
	netdev_connect(dev->irq);

	printk(KERN_INFO "%s: hosteth=%s simfd=%d, HwAddr",
	dev->name, simeth_device, local->simfd);
	for(i = 0; i < ETH_ALEN; i++) {
	printk(" %2.2x", dev->dev_addr[i]);
	}
	printk(", IRQ %d\n", dev->irq);

	return 0;
	}

	/*
	* actually binds the device to an interrupt vector
	*/
	static int
	simeth_open(struct net_device *dev)
	{
	if (request_irq(dev->irq, simeth_interrupt, 0, "simeth", dev)) {
	printk(KERN_WARNING "simeth: unable to get IRQ %d.\n", dev->irq);
	return -EAGAIN;
	}

	netif_start_queue(dev);

	return 0;
	}

	/* copied from lapbether.c */
	static __inline__ int dev_is_ethdev(struct net_device *dev)
	{
	return ( dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5));
	}


	/*
	* Handler for IFF_UP or IFF_DOWN
	*
	* The reason for that is that we don't want to be interrupted when the
	* interface is down. There is no way to unconnect in the simualtor. Instead
	* we use this function to shutdown packet processing in the frame filter
	* in the simulator. Thus no interrupts are generated
	*
	*
	* That's also the place where we pass the IP address of this device to the
	* simulator so that that we can start filtering packets for it
	*
	* There may be a better way of doing this, but I don't know which yet.
	*/
	static int
	simeth_device_event(struct notifier_block this,unsigned long event, void ptr)
	{
	struct net_device *dev = ptr;
	struct simeth_local *local;
	struct in_device *in_dev;
	struct in_ifaddr **ifap = NULL;
	struct in_ifaddr *ifa = NULL;
	int r;


	if ( ! dev ) {
	printk(KERN_WARNING "simeth_device_event dev=0\n");
	return NOTIFY_DONE;
	}

	if ( event != NETDEV_UP && event != NETDEV_DOWN ) return NOTIFY_DONE;

	/*
	* Check whether or not it's for an ethernet device
	*
	* XXX Fixme: This works only as long as we support one
	* type of ethernet device.
	*/
	if ( !dev_is_ethdev(dev) ) return NOTIFY_DONE;

	if ((in_dev=dev->ip_ptr) != NULL) {
	for (ifap=&in_dev->ifa_list; (ifa=*ifap) != NULL; ifap=&ifa->ifa_next)
	if (strcmp(dev->name, ifa->ifa_label) == 0) break;
	}
	if ( ifa == NULL ) {
	printk(KERN_ERR "simeth_open: can't find device %s's ifa\n", dev->name);
	return NOTIFY_DONE;
	}

	printk(KERN_INFO "simeth_device_event: %s ipaddr=0x%x\n",
	dev->name, htonl(ifa->ifa_local));

	/*
	* XXX Fix me
	* if the device was up, and we're simply reconfiguring it, not sure
	* we get DOWN then UP.
	*/

	local = dev->priv;
	/* now do it for real */
	r = event == NETDEV_UP ?
	netdev_attach(local->simfd, dev->irq, htonl(ifa->ifa_local)):
	netdev_detach(local->simfd);

	printk(KERN_INFO "simeth: netdev_attach/detach: event=%s ->%d\n",
	event == NETDEV_UP ? "attach":"detach", r);

	return NOTIFY_DONE;
	}

	static int
	simeth_close(struct net_device *dev)
	{
	netif_stop_queue(dev);

	free_irq(dev->irq, dev);

	return 0;
	}

	/*
	* Only used for debug
	*/
	static void
	frame_print(unsigned char from, unsigned char frame, int len)
	{
	int i;

	printk("%s: (%d) %02x", from, len, frame[0] & 0xff);
	for(i=1; i < 6; i++ ) {
	printk(":%02x", frame[i] &0xff);
	}
	printk(" %2x", frame[6] &0xff);
	for(i=7; i < 12; i++ ) {
	printk(":%02x", frame[i] &0xff);
	}
	printk(" [%02x%02x]\n", frame[12], frame[13]);

	for(i=14; i < len; i++ ) {
	printk("%02x ", frame[i] &0xff);
	if ( (i%10)==0) printk("\n");
	}
	printk("\n");
	}


	/*
	* Function used to transmit of frame, very last one on the path before
	* going to the simulator.
	*/
	static int
	simeth_tx(struct sk_buff skb, struct net_device dev)
	{
	struct simeth_local *local = dev->priv;

	#if 0
	/* ensure we have at least ETH_ZLEN bytes (min frame size) */
	unsigned int length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
	/* Where do the extra padding bytes comes from inthe skbuff ? */
	#else
	/* the real driver in the host system is going to take care of that
	* or maybe it's the NIC itself.
	*/
	unsigned int length = skb->len;
	#endif

	local->stats.tx_bytes += skb->len;
	local->stats.tx_packets++;


	if (simeth_debug > 5) frame_print("simeth_tx", skb->data, length);

	netdev_send(local->simfd, skb->data, length);

	/*
	* we are synchronous on write, so we don't simulate a
	* trasnmit complete interrupt, thus we don't need to arm a tx
	*/

	dev_kfree_skb(skb);
	return 0;
	}

	static inline struct sk_buff *
	make_new_skb(struct net_device *dev)
	{
	struct sk_buff *nskb;

	/*
	* The +2 is used to make sure that the IP header is nicely
	* aligned (on 4byte boundary I assume 14+2=16)
	*/
	nskb = dev_alloc_skb(SIMETH_FRAME_SIZE + 2);
	if ( nskb == NULL ) {
	printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
	return NULL;
	}
	nskb->dev = dev;

	skb_reserve(nskb, 2); /* Align IP on 16 byte boundaries */

	skb_put(nskb,SIMETH_FRAME_SIZE);

	return nskb;
	}

	/*
	* called from interrupt handler to process a received frame
	*/
	static int
	simeth_rx(struct net_device *dev)
	{
	struct simeth_local *local;
	struct sk_buff *skb;
	int len;
	int rcv_count = SIMETH_RECV_MAX;

	local = dev->priv;
	/*
	* the loop concept has been borrowed from other drivers
	* looks to me like it's a throttling thing to avoid pushing to many
	* packets at one time into the stack. Making sure we can process them
	* upstream and make forward progress overall
	*/
	do {
	if ( (skb=make_new_skb(dev)) == NULL ) {
	printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
	local->stats.rx_dropped++;
	return 0;
	}
	/*
	* Read only one frame at a time
	*/
	len = netdev_read(local->simfd, skb->data, SIMETH_FRAME_SIZE);
	if ( len == 0 ) {
	if ( simeth_debug > 0 ) printk(KERN_WARNING "%s: count=%d netdev_read=0\n",
	dev->name, SIMETH_RECV_MAX-rcv_count);
	break;
	}
	#if 0
	/*
	* XXX Fix me
	* Should really do a csum+copy here
	*/
	memcpy(skb->data, frame, len);
	#endif
	skb->protocol = eth_type_trans(skb, dev);

	if ( simeth_debug > 6 ) frame_print("simeth_rx", skb->data, len);

	/*
	* push the packet up & trigger software interrupt
	*/
	netif_rx(skb);

	local->stats.rx_packets++;
	local->stats.rx_bytes += len;

	} while ( --rcv_count );

	return len; /* 0 = nothing left to read, otherwise, we can try again */
	}

	/*
	* Interrupt handler (Yes, we can do it too !!!)
	*/
	static irqreturn_t
	simeth_interrupt(int irq, void dev_id, struct pt_regs regs)
	{
	struct net_device *dev = dev_id;

	if ( dev == NULL ) {
	printk(KERN_WARNING "simeth: irq %d for unknown device\n", irq);
	return IRQ_NONE;
	}

	/*
	* very simple loop because we get interrupts only when receiving
	*/
	while (simeth_rx(dev));
	return IRQ_HANDLED;
	}

	static struct net_device_stats *
	simeth_get_stats(struct net_device *dev)
	{
	struct simeth_local *local = dev->priv;

	return &local->stats;
	}

	/* fake multicast ability */
	static void
	set_multicast_list(struct net_device *dev)
	{
	printk(KERN_WARNING "%s: set_multicast_list called\n", dev->name);
	}

	__initcall(simeth_probe);