dev.c

		local_irq_disable();
		head = sd->output_queue;
		sd->output_queue = NULL;
		local_irq_enable();

		while (head) {
			struct Qdisc *q = head;
			spinlock_t *root_lock;

			head = head->next_sched;

			root_lock = qdisc_lock(q);
			if (spin_trylock(root_lock)) {
				smp_mb__before_clear_bit();
				clear_bit(__QDISC_STATE_SCHED,
					  &q->state);
				qdisc_run(q);
				spin_unlock(root_lock);
			} else {
				if (!test_bit(__QDISC_STATE_DEACTIVATED,
					      &q->state)) {
					__netif_reschedule(q);
				} else {
					smp_mb__before_clear_bit();
					clear_bit(__QDISC_STATE_SCHED,
						  &q->state);
				}
			}
		}
	}
}

static inline int deliver_skb(struct sk_buff *skb,
			      struct packet_type *pt_prev,
			      struct net_device *orig_dev)
{
	atomic_inc(&skb->users);
	return pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
}

#if defined(CONFIG_BRIDGE) || defined (CONFIG_BRIDGE_MODULE)
/* These hooks defined here for ATM */
struct net_bridge;
struct net_bridge_fdb_entry *(*br_fdb_get_hook)(struct net_bridge *br,
						unsigned char *addr);
void (*br_fdb_put_hook)(struct net_bridge_fdb_entry *ent) __read_mostly;

/*
 * If bridge module is loaded call bridging hook.
 *  returns NULL if packet was consumed.
 */
struct sk_buff *(*br_handle_frame_hook)(struct net_bridge_port *p,
					struct sk_buff *skb) __read_mostly;
static inline struct sk_buff *handle_bridge(struct sk_buff *skb,
					    struct packet_type **pt_prev, int *ret,
					    struct net_device *orig_dev)
{
	struct net_bridge_port *port;

	if (skb->pkt_type == PACKET_LOOPBACK ||
	    (port = rcu_dereference(skb->dev->br_port)) == NULL)
		return skb;

	if (*pt_prev) {
		*ret = deliver_skb(skb, *pt_prev, orig_dev);
		*pt_prev = NULL;
	}

	return br_handle_frame_hook(port, skb);
}
#else
#define handle_bridge(skb, pt_prev, ret, orig_dev)	(skb)
#endif

#if defined(CONFIG_MACVLAN) || defined(CONFIG_MACVLAN_MODULE)
struct sk_buff *(*macvlan_handle_frame_hook)(struct sk_buff *skb) __read_mostly;
EXPORT_SYMBOL_GPL(macvlan_handle_frame_hook);

static inline struct sk_buff *handle_macvlan(struct sk_buff *skb,
					     struct packet_type **pt_prev,
					     int *ret,
					     struct net_device *orig_dev)
{
	if (skb->dev->macvlan_port == NULL)
		return skb;

	if (*pt_prev) {
		*ret = deliver_skb(skb, *pt_prev, orig_dev);
		*pt_prev = NULL;
	}
	return macvlan_handle_frame_hook(skb);
}
#else
#define handle_macvlan(skb, pt_prev, ret, orig_dev)	(skb)
#endif

#ifdef CONFIG_NET_CLS_ACT
/* TODO: Maybe we should just force sch_ingress to be compiled in
 * when CONFIG_NET_CLS_ACT is? otherwise some useless instructions
 * a compare and 2 stores extra right now if we dont have it on
 * but have CONFIG_NET_CLS_ACT
 * NOTE: This doesnt stop any functionality; if you dont have
 * the ingress scheduler, you just cant add policies on ingress.
 *
 */
static int ing_filter(struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	u32 ttl = G_TC_RTTL(skb->tc_verd);
	struct netdev_queue *rxq;
	int result = TC_ACT_OK;
	struct Qdisc *q;

	if (MAX_RED_LOOP < ttl++) {
		printk(KERN_WARNING
		       "Redir loop detected Dropping packet (%d->%d)\n",
		       skb->iif, dev->ifindex);
		return TC_ACT_SHOT;
	}

	skb->tc_verd = SET_TC_RTTL(skb->tc_verd, ttl);
	skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);

	rxq = &dev->rx_queue;

	q = rxq->qdisc;
	if (q != &noop_qdisc) {
		spin_lock(qdisc_lock(q));
		if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
			result = qdisc_enqueue_root(skb, q);
		spin_unlock(qdisc_lock(q));
	}

	return result;
}

static inline struct sk_buff *handle_ing(struct sk_buff *skb,
					 struct packet_type **pt_prev,
					 int *ret, struct net_device *orig_dev)
{
	if (skb->dev->rx_queue.qdisc == &noop_qdisc)
		goto out;

	if (*pt_prev) {
		*ret = deliver_skb(skb, *pt_prev, orig_dev);
		*pt_prev = NULL;
	} else {
		/* Huh? Why does turning on AF_PACKET affect this? */
		skb->tc_verd = SET_TC_OK2MUNGE(skb->tc_verd);
	}

	switch (ing_filter(skb)) {
	case TC_ACT_SHOT:
	case TC_ACT_STOLEN:
		kfree_skb(skb);
		return NULL;
	}

out:
	skb->tc_verd = 0;
	return skb;
}
#endif

/*
 * 	netif_nit_deliver - deliver received packets to network taps
 * 	@skb: buffer
 *
 * 	This function is used to deliver incoming packets to network
 * 	taps. It should be used when the normal netif_receive_skb path
 * 	is bypassed, for example because of VLAN acceleration.
 */
void netif_nit_deliver(struct sk_buff *skb)
{
	struct packet_type *ptype;

	if (list_empty(&ptype_all))
		return;

	skb_reset_network_header(skb);
	skb_reset_transport_header(skb);
	skb->mac_len = skb->network_header - skb->mac_header;

	rcu_read_lock();
	list_for_each_entry_rcu(ptype, &ptype_all, list) {
		if (!ptype->dev || ptype->dev == skb->dev)
			deliver_skb(skb, ptype, skb->dev);
	}
	rcu_read_unlock();
}

/**
 *	netif_receive_skb - process receive buffer from network
 *	@skb: buffer to process
 *
 *	netif_receive_skb() is the main receive data processing function.
 *	It always succeeds. The buffer may be dropped during processing
 *	for congestion control or by the protocol layers.
 *
 *	This function may only be called from softirq context and interrupts
 *	should be enabled.
 *
 *	Return values (usually ignored):
 *	NET_RX_SUCCESS: no congestion
 *	NET_RX_DROP: packet was dropped
 */
int netif_receive_skb(struct sk_buff *skb)
{
	struct packet_type *ptype, *pt_prev;
	struct net_device *orig_dev;
	struct net_device *null_or_orig;
	int ret = NET_RX_DROP;
	__be16 type;

	if (skb->vlan_tci && vlan_hwaccel_do_receive(skb))
		return NET_RX_SUCCESS;

	/* if we've gotten here through NAPI, check netpoll */
	if (netpoll_receive_skb(skb))
		return NET_RX_DROP;

	if (!skb->tstamp.tv64)
		net_timestamp(skb);

	if (!skb->iif)
		skb->iif = skb->dev->ifindex;

	null_or_orig = NULL;
	orig_dev = skb->dev;
	if (orig_dev->master) {
		if (skb_bond_should_drop(skb))
			null_or_orig = orig_dev; /* deliver only exact match */
		else
			skb->dev = orig_dev->master;
	}

	__get_cpu_var(netdev_rx_stat).total++;

	skb_reset_network_header(skb);
	skb_reset_transport_header(skb);
	skb->mac_len = skb->network_header - skb->mac_header;

	pt_prev = NULL;

	rcu_read_lock();

	/* Don't receive packets in an exiting network namespace */
	if (!net_alive(dev_net(skb->dev))) {
		kfree_skb(skb);
		goto out;
	}

#ifdef CONFIG_NET_CLS_ACT
	if (skb->tc_verd & TC_NCLS) {
		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
		goto ncls;
	}
#endif

	list_for_each_entry_rcu(ptype, &ptype_all, list) {
		if (ptype->dev == null_or_orig || ptype->dev == skb->dev ||
		    ptype->dev == orig_dev) {
			if (pt_prev)
				ret = deliver_skb(skb, pt_prev, orig_dev);
			pt_prev = ptype;
		}
	}

#ifdef CONFIG_NET_CLS_ACT
	skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
	if (!skb)
		goto out;
ncls:
#endif

	skb = handle_bridge(skb, &pt_prev, &ret, orig_dev);
	if (!skb)
		goto out;
	skb = handle_macvlan(skb, &pt_prev, &ret, orig_dev);
	if (!skb)
		goto out;

	skb_orphan(skb);

	type = skb->protocol;
	list_for_each_entry_rcu(ptype,
			&ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {
		if (ptype->type == type &&
		    (ptype->dev == null_or_orig || ptype->dev == skb->dev ||
		     ptype->dev == orig_dev)) {
			if (pt_prev)
				ret = deliver_skb(skb, pt_prev, orig_dev);
			pt_prev = ptype;
		}
	}

	if (pt_prev) {
		ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
	} else {
		kfree_skb(skb);
		/* Jamal, now you will not able to escape explaining
		 * me how you were going to use this. :-)
		 */
		ret = NET_RX_DROP;
	}

out:
	rcu_read_unlock();
	return ret;
}

/* Network device is going away, flush any packets still pending  */
static void flush_backlog(void *arg)
{
	struct net_device *dev = arg;
	struct softnet_data *queue = &__get_cpu_var(softnet_data);
	struct sk_buff *skb, *tmp;

	skb_queue_walk_safe(&queue->input_pkt_queue, skb, tmp)
		if (skb->dev == dev) {
			__skb_unlink(skb, &queue->input_pkt_queue);
			kfree_skb(skb);
		}
}

static int napi_gro_complete(struct sk_buff *skb)
{
	struct packet_type *ptype;
	__be16 type = skb->protocol;
	struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
	int err = -ENOENT;

	if (NAPI_GRO_CB(skb)->count == 1)
		goto out;

	rcu_read_lock();
	list_for_each_entry_rcu(ptype, head, list) {
		if (ptype->type != type || ptype->dev || !ptype->gro_complete)
			continue;

		err = ptype->gro_complete(skb);
		break;
	}
	rcu_read_unlock();

	if (err) {
		WARN_ON(&ptype->list == head);
		kfree_skb(skb);
		return NET_RX_SUCCESS;
	}

out:
	skb_shinfo(skb)->gso_size = 0;
	return netif_receive_skb(skb);
}

void napi_gro_flush(struct napi_struct *napi)
{
	struct sk_buff *skb, *next;

	for (skb = napi->gro_list; skb; skb = next) {
		next = skb->next;
		skb->next = NULL;
		napi_gro_complete(skb);
	}

	napi->gro_count = 0;
	napi->gro_list = NULL;
}
EXPORT_SYMBOL(napi_gro_flush);

void *skb_gro_header(struct sk_buff *skb, unsigned int hlen)
{
	unsigned int offset = skb_gro_offset(skb);

	hlen += offset;
	if (hlen <= skb_headlen(skb))
		return skb->data + offset;

	if (unlikely(!skb_shinfo(skb)->nr_frags ||
		     skb_shinfo(skb)->frags[0].size <=
		     hlen - skb_headlen(skb) ||
		     PageHighMem(skb_shinfo(skb)->frags[0].page)))
		return pskb_may_pull(skb, hlen) ? skb->data + offset : NULL;

	return page_address(skb_shinfo(skb)->frags[0].page) +
	       skb_shinfo(skb)->frags[0].page_offset +
	       offset - skb_headlen(skb);
}
EXPORT_SYMBOL(skb_gro_header);

int dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
	struct sk_buff **pp = NULL;
	struct packet_type *ptype;
	__be16 type = skb->protocol;
	struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
	int same_flow;
	int mac_len;
	int ret;

	if (!(skb->dev->features & NETIF_F_GRO))
		goto normal;

	if (skb_is_gso(skb) || skb_shinfo(skb)->frag_list)
		goto normal;

	rcu_read_lock();
	list_for_each_entry_rcu(ptype, head, list) {
		if (ptype->type != type || ptype->dev || !ptype->gro_receive)
			continue;

		skb_set_network_header(skb, skb_gro_offset(skb));
		mac_len = skb->network_header - skb->mac_header;
		skb->mac_len = mac_len;
		NAPI_GRO_CB(skb)->same_flow = 0;
		NAPI_GRO_CB(skb)->flush = 0;
		NAPI_GRO_CB(skb)->free = 0;

		pp = ptype->gro_receive(&napi->gro_list, skb);
		break;
	}
	rcu_read_unlock();

	if (&ptype->list == head)
		goto normal;

	same_flow = NAPI_GRO_CB(skb)->same_flow;
	ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED;

	if (pp) {
		struct sk_buff *nskb = *pp;

		*pp = nskb->next;
		nskb->next = NULL;
		napi_gro_complete(nskb);
		napi->gro_count--;
	}

	if (same_flow)
		goto ok;

	if (NAPI_GRO_CB(skb)->flush || napi->gro_count >= MAX_GRO_SKBS)
		goto normal;

	napi->gro_count++;
	NAPI_GRO_CB(skb)->count = 1;
	skb_shinfo(skb)->gso_size = skb_gro_len(skb);
	skb->next = napi->gro_list;
	napi->gro_list = skb;
	ret = GRO_HELD;

pull:
	if (unlikely(!pskb_may_pull(skb, skb_gro_offset(skb)))) {
		if (napi->gro_list == skb)
			napi->gro_list = skb->next;
		ret = GRO_DROP;
	}

ok:
	return ret;

normal:
	ret = GRO_NORMAL;
	goto pull;
}
EXPORT_SYMBOL(dev_gro_receive);

static int __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
	struct sk_buff *p;

	for (p = napi->gro_list; p; p = p->next) {
		NAPI_GRO_CB(p)->same_flow = !compare_ether_header(
			skb_mac_header(p), skb_gro_mac_header(skb));
		NAPI_GRO_CB(p)->flush = 0;
	}

	return dev_gro_receive(napi, skb);
}

int napi_skb_finish(int ret, struct sk_buff *skb)
{
	int err = NET_RX_SUCCESS;

	switch (ret) {
	case GRO_NORMAL:
		return netif_receive_skb(skb);

	case GRO_DROP:
		err = NET_RX_DROP;
		/* fall through */

	case GRO_MERGED_FREE:
		kfree_skb(skb);
		break;
	}

	return err;
}
EXPORT_SYMBOL(napi_skb_finish);

int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
	skb_gro_reset_offset(skb);

	return napi_skb_finish(__napi_gro_receive(napi, skb), skb);
}
EXPORT_SYMBOL(napi_gro_receive);

void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
{
	__skb_pull(skb, skb_headlen(skb));
	skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));

	napi->skb = skb;
}
EXPORT_SYMBOL(napi_reuse_skb);

struct sk_buff *napi_fraginfo_skb(struct napi_struct *napi,
				  struct napi_gro_fraginfo *info)
{
	struct net_device *dev = napi->dev;
	struct sk_buff *skb = napi->skb;
	struct ethhdr *eth;
	skb_frag_t *frag;
	int i;

	napi->skb = NULL;

	if (!skb) {
		skb = netdev_alloc_skb(dev, GRO_MAX_HEAD + NET_IP_ALIGN);
		if (!skb)
			goto out;

		skb_reserve(skb, NET_IP_ALIGN);
	}

	BUG_ON(info->nr_frags > MAX_SKB_FRAGS);
	frag = &info->frags[info->nr_frags - 1];

	for (i = skb_shinfo(skb)->nr_frags; i < info->nr_frags; i++) {
		skb_fill_page_desc(skb, i, frag->page, frag->page_offset,
				   frag->size);
		frag++;
	}
	skb_shinfo(skb)->nr_frags = info->nr_frags;

	skb->data_len = info->len;
	skb->len += info->len;
	skb->truesize += info->len;

	skb_reset_mac_header(skb);
	skb_gro_reset_offset(skb);

	eth = skb_gro_header(skb, sizeof(*eth));
	if (!eth) {
		napi_reuse_skb(napi, skb);
		skb = NULL;
		goto out;
	}

	skb_gro_pull(skb, sizeof(*eth));

	/*
	 * This works because the only protocols we care about don't require
	 * special handling.  We'll fix it up properly at the end.
	 */
	skb->protocol = eth->h_proto;

	skb->ip_summed = info->ip_summed;
	skb->csum = info->csum;

out:
	return skb;
}
EXPORT_SYMBOL(napi_fraginfo_skb);

int napi_frags_finish(struct napi_struct *napi, struct sk_buff *skb, int ret)
{
	int err = NET_RX_SUCCESS;

	switch (ret) {
	case GRO_NORMAL:
	case GRO_HELD:
		skb->protocol = eth_type_trans(skb, napi->dev);

		if (ret == GRO_NORMAL)
			return netif_receive_skb(skb);

		skb_gro_pull(skb, -ETH_HLEN);
		break;

	case GRO_DROP:
		err = NET_RX_DROP;
		/* fall through */

	case GRO_MERGED_FREE:
		napi_reuse_skb(napi, skb);
		break;
	}

	return err;
}
EXPORT_SYMBOL(napi_frags_finish);

int napi_gro_frags(struct napi_struct *napi, struct napi_gro_fraginfo *info)
{
	struct sk_buff *skb = napi_fraginfo_skb(napi, info);

	if (!skb)
		return NET_RX_DROP;

	return napi_frags_finish(napi, skb, __napi_gro_receive(napi, skb));
}
EXPORT_SYMBOL(napi_gro_frags);

static int process_backlog(struct napi_struct *napi, int quota)
{
	int work = 0;
	struct softnet_data *queue = &__get_cpu_var(softnet_data);
	unsigned long start_time = jiffies;

	napi->weight = weight_p;
	do {
		struct sk_buff *skb;

		local_irq_disable();
		skb = __skb_dequeue(&queue->input_pkt_queue);
		if (!skb) {
			__napi_complete(napi);
			local_irq_enable();
			break;
		}
		local_irq_enable();

		napi_gro_receive(napi, skb);
	} while (++work < quota && jiffies == start_time);

	napi_gro_flush(napi);

	return work;
}

/**
 * __napi_schedule - schedule for receive
 * @n: entry to schedule
 *
 * The entry's receive function will be scheduled to run
 */
void __napi_schedule(struct napi_struct *n)
{
	unsigned long flags;

	local_irq_save(flags);
	list_add_tail(&n->poll_list, &__get_cpu_var(softnet_data).poll_list);
	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
	local_irq_restore(flags);
}
EXPORT_SYMBOL(__napi_schedule);

void __napi_complete(struct napi_struct *n)
{
	BUG_ON(!test_bit(NAPI_STATE_SCHED, &n->state));
	BUG_ON(n->gro_list);

	list_del(&n->poll_list);
	smp_mb__before_clear_bit();
	clear_bit(NAPI_STATE_SCHED, &n->state);
}
EXPORT_SYMBOL(__napi_complete);

void napi_complete(struct napi_struct *n)
{
	unsigned long flags;

	/*
	 * don't let napi dequeue from the cpu poll list
	 * just in case its running on a different cpu
	 */
	if (unlikely(test_bit(NAPI_STATE_NPSVC, &n->state)))
		return;

	napi_gro_flush(n);
	local_irq_save(flags);
	__napi_complete(n);
	local_irq_restore(flags);
}
EXPORT_SYMBOL(napi_complete);

void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
		    int (*poll)(struct napi_struct *, int), int weight)
{
	INIT_LIST_HEAD(&napi->poll_list);
	napi->gro_count = 0;
	napi->gro_list = NULL;
	napi->skb = NULL;
	napi->poll = poll;
	napi->weight = weight;
	list_add(&napi->dev_list, &dev->napi_list);
	napi->dev = dev;
#ifdef CONFIG_NETPOLL
	spin_lock_init(&napi->poll_lock);
	napi->poll_owner = -1;
#endif
	set_bit(NAPI_STATE_SCHED, &napi->state);
}
EXPORT_SYMBOL(netif_napi_add);

void netif_napi_del(struct napi_struct *napi)
{
	struct sk_buff *skb, *next;

	list_del_init(&napi->dev_list);
	kfree(napi->skb);

	for (skb = napi->gro_list; skb; skb = next) {
		next = skb->next;
		skb->next = NULL;
		kfree_skb(skb);
	}

	napi->gro_list = NULL;
	napi->gro_count = 0;
}
EXPORT_SYMBOL(netif_napi_del);


static void net_rx_action(struct softirq_action *h)
{
	struct list_head *list = &__get_cpu_var(softnet_data).poll_list;
	unsigned long time_limit = jiffies + 2;
	int budget = netdev_budget;
	void *have;

	local_irq_disable();

	while (!list_empty(list)) {
		struct napi_struct *n;
		int work, weight;

		/* If softirq window is exhuasted then punt.
		 * Allow this to run for 2 jiffies since which will allow
		 * an average latency of 1.5/HZ.
		 */
		if (unlikely(budget <= 0 || time_after(jiffies, time_limit)))
			goto softnet_break;

		local_irq_enable();

		/* Even though interrupts have been re-enabled, this
		 * access is safe because interrupts can only add new
		 * entries to the tail of this list, and only ->poll()
		 * calls can remove this head entry from the list.
		 */
		n = list_entry(list->next, struct napi_struct, poll_list);

		have = netpoll_poll_lock(n);

		weight = n->weight;

		/* This NAPI_STATE_SCHED test is for avoiding a race
		 * with netpoll's poll_napi().  Only the entity which
		 * obtains the lock and sees NAPI_STATE_SCHED set will
		 * actually make the ->poll() call.  Therefore we avoid
		 * accidently calling ->poll() when NAPI is not scheduled.
		 */
		work = 0;
		if (test_bit(NAPI_STATE_SCHED, &n->state))
			work = n->poll(n, weight);

		WARN_ON_ONCE(work > weight);

		budget -= work;

		local_irq_disable();

		/* Drivers must not modify the NAPI state if they
		 * consume the entire weight.  In such cases this code
		 * still "owns" the NAPI instance and therefore can
		 * move the instance around on the list at-will.
		 */
		if (unlikely(work == weight)) {
			if (unlikely(napi_disable_pending(n)))
				__napi_complete(n);
			else
				list_move_tail(&n->poll_list, list);
		}

		netpoll_poll_unlock(have);
	}
out:
	local_irq_enable();

#ifdef CONFIG_NET_DMA
	/*
	 * There may not be any more sk_buffs coming right now, so push
	 * any pending DMA copies to hardware
	 */
	dma_issue_pending_all();
#endif

	return;

softnet_break:
	__get_cpu_var(netdev_rx_stat).time_squeeze++;
	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
	goto out;
}

static gifconf_func_t * gifconf_list [NPROTO];

/**
 *	register_gifconf	-	register a SIOCGIF handler
 *	@family: Address family
 *	@gifconf: Function handler
 *
 *	Register protocol dependent address dumping routines. The handler
 *	that is passed must not be freed or reused until it has been replaced
 *	by another handler.
 */
int register_gifconf(unsigned int family, gifconf_func_t * gifconf)
{
	if (family >= NPROTO)
		return -EINVAL;
	gifconf_list[family] = gifconf;
	return 0;
}


/*
 *	Map an interface index to its name (SIOCGIFNAME)
 */

/*
 *	We need this ioctl for efficient implementation of the
 *	if_indextoname() function required by the IPv6 API.  Without
 *	it, we would have to search all the interfaces to find a
 *	match.  --pb
 */

static int dev_ifname(struct net *net, struct ifreq __user *arg)
{
	struct net_device *dev;
	struct ifreq ifr;

	/*
	 *	Fetch the caller's info block.
	 */

	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
		return -EFAULT;

	read_lock(&dev_base_lock);
	dev = __dev_get_by_index(net, ifr.ifr_ifindex);
	if (!dev) {
		read_unlock(&dev_base_lock);
		return -ENODEV;
	}

	strcpy(ifr.ifr_name, dev->name);
	read_unlock(&dev_base_lock);

	if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
		return -EFAULT;
	return 0;
}

/*
 *	Perform a SIOCGIFCONF call. This structure will change
 *	size eventually, and there is nothing I can do about it.
 *	Thus we will need a 'compatibility mode'.
 */

static int dev_ifconf(struct net *net, char __user *arg)
{
	struct ifconf ifc;
	struct net_device *dev;
	char __user *pos;
	int len;
	int total;
	int i;

	/*
	 *	Fetch the caller's info block.
	 */

	if (copy_from_user(&ifc, arg, sizeof(struct ifconf)))
		return -EFAULT;

	pos = ifc.ifc_buf;
	len = ifc.ifc_len;

	/*
	 *	Loop over the interfaces, and write an info block for each.
	 */

	total = 0;
	for_each_netdev(net, dev) {
		for (i = 0; i < NPROTO; i++) {
			if (gifconf_list[i]) {
				int done;
				if (!pos)
					done = gifconf_list[i](dev, NULL, 0);
				else
					done = gifconf_list[i](dev, pos + total,
							       len - total);
				if (done < 0)
					return -EFAULT;
				total += done;
			}
		}
	}

	/*
	 *	All done.  Write the updated control block back to the caller.
	 */
	ifc.ifc_len = total;

	/*
	 * 	Both BSD and Solaris return 0 here, so we do too.
	 */
	return copy_to_user(arg, &ifc, sizeof(struct ifconf)) ? -EFAULT : 0;
}

#ifdef CONFIG_PROC_FS
/*
 *	This is invoked by the /proc filesystem handler to display a device
 *	in detail.
 */
void *dev_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(dev_base_lock)
{
	struct net *net = seq_file_net(seq);
	loff_t off;
	struct net_device *dev;

	read_lock(&dev_base_lock);
	if (!*pos)
		return SEQ_START_TOKEN;

	off = 1;
	for_each_netdev(net, dev)
		if (off++ == *pos)
			return dev;

	return NULL;
}

void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct net *net = seq_file_net(seq);
	++*pos;
	return v == SEQ_START_TOKEN ?
		first_net_device(net) : next_net_device((struct net_device *)v);
}

void dev_seq_stop(struct seq_file *seq, void *v)
	__releases(dev_base_lock)
{
	read_unlock(&dev_base_lock);
}

static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev)
{
	const struct net_device_stats *stats = dev_get_stats(dev);

	seq_printf(seq, "%6s:%8lu %7lu %4lu %4lu %4lu %5lu %10lu %9lu "
		   "%8lu %7lu %4lu %4lu %4lu %5lu %7lu %10lu\n",
		   dev->name, stats->rx_bytes, stats->rx_packets,
		   stats->rx_errors,
		   stats->rx_dropped + stats->rx_missed_errors,
		   stats->rx_fifo_errors,
		   stats->rx_length_errors + stats->rx_over_errors +
		    stats->rx_crc_errors + stats->rx_frame_errors,
		   stats->rx_compressed, stats->multicast,
		   stats->tx_bytes, stats->tx_packets,
		   stats->tx_errors, stats->tx_dropped,
		   stats->tx_fifo_errors, stats->collisions,
		   stats->tx_carrier_errors +
		    stats->tx_aborted_errors +
		    stats->tx_window_errors +
		    stats->tx_heartbeat_errors,
		   stats->tx_compressed);
}

/*
 *	Called from the PROCfs module. This now uses the new arbitrary sized
 *	/proc/net interface to create /proc/net/dev
 */
static int dev_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_puts(seq, "Inter-|   Receive                            "
			      "                    |  Transmit\n"
			      " face |bytes    packets errs drop fifo frame "
			      "compressed multicast|bytes    packets errs "
			      "drop fifo colls carrier compressed\n");
	else