patch-2.3.15 linux/net/atm/clip.c

• Lines: 695
• Date: Mon Aug 23 09:56:32 1999
• Orig file: v2.3.14/linux/net/atm/clip.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.14/linux/net/atm/clip.c linux/net/atm/clip.c
@@ -0,0 +1,694 @@
+/* net/atm/clip.c - RFC1577 Classical IP over ATM */
+
+/* Written 1995-1999 by Werner Almesberger, EPFL LRC/ICA */
+
+
+#include <linux/config.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/kernel.h> /* for UINT_MAX */
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/wait.h>
+#include <linux/timer.h>
+#include <linux/if_arp.h> /* for some manifest constants */
+#include <linux/notifier.h>
+#include <linux/atm.h>
+#include <linux/atmdev.h>
+#include <linux/atmclip.h>
+#include <linux/atmarp.h>
+#include <linux/ip.h> /* for net/route.h */
+#include <linux/in.h> /* for struct sockaddr_in */
+#include <linux/if.h> /* for IFF_UP */
+#include <linux/inetdevice.h>
+#include <net/route.h> /* for struct rtable and routing */
+#include <net/icmp.h> /* icmp_send */
+#include <asm/param.h> /* for HZ */
+#include <asm/byteorder.h> /* for htons etc. */
+#include <asm/system.h> /* save/restore_flags */
+#include <asm/uaccess.h>
+#include <asm/atomic.h>
+
+#include "common.h"
+#include "tunable.h"
+#include "resources.h"
+#include "ipcommon.h"
+#include <net/atmclip.h>
+
+
+#if 0
+#define DPRINTK(format,args...) printk(format,##args)
+#else
+#define DPRINTK(format,args...)
+#endif
+
+
+struct net_device *clip_devs = NULL;
+struct atm_vcc *atmarpd = NULL;
+static struct timer_list idle_timer = { NULL, NULL, 0L, 0L, NULL };
+static int start_timer = 1;
+
+
+static int to_atmarpd(enum atmarp_ctrl_type type,int itf,unsigned long ip)
+{
+	struct atmarp_ctrl *ctrl;
+	struct sk_buff *skb;
+
+	DPRINTK("to_atmarpd(%d)\n",type);
+	if (!atmarpd) return -EUNATCH;
+	skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);
+	if (!skb) return -ENOMEM;
+	ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));
+	ctrl->type = type;
+	ctrl->itf_num = itf;
+	ctrl->ip = ip;
+	atm_force_charge(atmarpd,skb->truesize);
+	skb_queue_tail(&atmarpd->recvq,skb);
+	wake_up(&atmarpd->sleep);
+	return 0;
+}
+
+
+static void link_vcc(struct clip_vcc *clip_vcc,struct atmarp_entry *entry)
+{
+	DPRINTK("link_vcc %p to entry %p (neigh %p)\n",clip_vcc,entry,
+	    entry->neigh);
+	clip_vcc->entry = entry;
+	clip_vcc->next = entry->vccs;
+	entry->vccs = clip_vcc;
+	entry->neigh->used = jiffies;
+}
+
+
+static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
+{
+	struct atmarp_entry *entry = clip_vcc->entry;
+	struct clip_vcc **walk;
+
+	if (!entry) {
+		printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n",clip_vcc);
+		return;
+	}
+	entry->neigh->used = jiffies;
+	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
+		if (*walk == clip_vcc) {
+			int error;
+
+			*walk = clip_vcc->next; /* atomic */
+			clip_vcc->entry = NULL;
+			if (entry->vccs) return;
+			entry->expires = jiffies-1;
+				/* force resolution or expiration */
+			error = neigh_update(entry->neigh,NULL,NUD_NONE,0,0);
+			if (error)
+				printk(KERN_CRIT "unlink_clip_vcc: "
+				    "neigh_update failed with %d\n",error);
+			return;
+		}
+	printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "
+	  "0x%p)\n",entry,clip_vcc);
+}
+
+
+static void idle_timer_check(unsigned long dummy)
+{
+	int i;
+
+	/*DPRINTK("idle_timer_check\n");*/
+	write_lock(&clip_tbl.lock);
+	for (i = 0; i <= NEIGH_HASHMASK; i++) {
+		struct neighbour **np;
+
+		for (np = &clip_tbl.hash_buckets[i]; *np;) {
+			struct neighbour *n = *np;
+			struct atmarp_entry *entry = NEIGH2ENTRY(n);
+			struct clip_vcc *clip_vcc;
+
+			for (clip_vcc = entry->vccs; clip_vcc;
+			    clip_vcc = clip_vcc->next)
+				if (clip_vcc->idle_timeout &&
+				    time_after(jiffies, clip_vcc->last_use+
+				    clip_vcc->idle_timeout)) {
+					DPRINTK("releasing vcc %p->%p of "
+					    "entry %p\n",clip_vcc,clip_vcc->vcc,
+					    entry);
+					atm_async_release_vcc(clip_vcc->vcc,
+					    -ETIMEDOUT);
+				}
+			if (entry->vccs ||
+			    time_before(jiffies, entry->expires)) {
+				np = &n->next;
+				continue;
+			}
+			if (atomic_read(&n->refcnt) > 1) {
+				struct sk_buff *skb;
+
+				DPRINTK("destruction postponed with ref %d\n",
+				    atomic_read(&n->refcnt));
+				while ((skb = skb_dequeue(&n->arp_queue)) !=
+				     NULL) 
+					dev_kfree_skb(skb);
+				np = &n->next;
+				continue;
+			}
+			*np = n->next;
+			DPRINTK("expired neigh %p\n",n);
+			n->dead = 1;
+			neigh_release(n);
+		}
+	}
+	mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
+	write_unlock(&clip_tbl.lock);
+}
+
+
+static int clip_arp_rcv(struct sk_buff *skb)
+{
+	struct atm_vcc *vcc;
+
+	DPRINTK("clip_arp_rcv\n");
+	vcc = ATM_SKB(skb)->vcc;
+	if (!vcc || !atm_charge(vcc,skb->truesize)) {
+		kfree_skb(skb);
+		return 0;
+	}
+	DPRINTK("pushing to %p\n",vcc);
+	DPRINTK("using %p\n",CLIP_VCC(vcc)->old_push);
+	CLIP_VCC(vcc)->old_push(vcc,skb);
+	return 0;
+}
+
+
+void clip_push(struct atm_vcc *vcc,struct sk_buff *skb)
+{
+	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
+
+	DPRINTK("clip push\n");
+	if (!skb) {
+		DPRINTK("removing VCC %p\n",clip_vcc);
+		if (clip_vcc->entry) unlink_clip_vcc(clip_vcc);
+		clip_vcc->old_push(vcc,NULL); /* pass on the bad news */
+		kfree(clip_vcc);
+		return;
+	}
+	atm_return(vcc,skb->truesize);
+	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
+		/* clip_vcc->entry == NULL if we don't have an IP address yet */
+	if (!skb->dev) {
+		kfree_skb(skb);
+		return;
+	}
+	ATM_SKB(skb)->vcc = vcc;
+	skb->mac.raw = skb->data;
+	if (!clip_vcc->encap || skb->len < RFC1483LLC_LEN || memcmp(skb->data,
+	    llc_oui,sizeof(llc_oui))) skb->protocol = htons(ETH_P_IP);
+	else {
+		skb->protocol = ((u16 *) skb->data)[3];
+		skb_pull(skb,RFC1483LLC_LEN);
+		if (skb->protocol == htons(ETH_P_ARP)) {
+			PRIV(skb->dev)->stats.rx_packets++;
+			clip_arp_rcv(skb);
+			return;
+		}
+	}
+	clip_vcc->last_use = jiffies;
+	PRIV(skb->dev)->stats.rx_packets++;
+	netif_rx(skb);
+}
+
+
+static void clip_neigh_destroy(struct neighbour *neigh)
+{
+	DPRINTK("clip_neigh_destroy (neigh %p)\n",neigh);
+	if (NEIGH2ENTRY(neigh)->vccs)
+		printk(KERN_CRIT "clip_neigh_destroy: vccs != NULL !!!\n");
+	NEIGH2ENTRY(neigh)->vccs = (void *) 0xdeadbeef;
+}
+
+
+static void clip_neigh_solicit(struct neighbour *neigh,struct sk_buff *skb)
+{
+	DPRINTK("clip_neigh_solicit (neigh %p, skb %p)\n",neigh,skb);
+	to_atmarpd(act_need,PRIV(neigh->dev)->number,NEIGH2ENTRY(neigh)->ip);
+}
+
+
+static void clip_neigh_error(struct neighbour *neigh,struct sk_buff *skb)
+{
+#ifndef CONFIG_ATM_CLIP_NO_ICMP
+	icmp_send(skb,ICMP_DEST_UNREACH,ICMP_HOST_UNREACH,0);
+#endif
+	kfree_skb(skb);
+}
+
+
+static struct neigh_ops clip_neigh_ops = {
+	AF_INET,		/* family */
+	clip_neigh_destroy,	/* destructor */
+	clip_neigh_solicit,	/* solicit */
+	clip_neigh_error,	/* error_report */
+	dev_queue_xmit,		/* output */
+	dev_queue_xmit,		/* connected_output */
+	dev_queue_xmit,		/* hh_output */
+	dev_queue_xmit		/* queue_xmit */
+};
+
+
+static int clip_constructor(struct neighbour *neigh)
+{
+	struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
+	struct net_device *dev = neigh->dev;
+	struct in_device *in_dev = dev->ip_ptr;
+
+	DPRINTK("clip_constructor (neigh %p, entry %p)\n",neigh,entry);
+	if (!in_dev) return -EINVAL;
+	neigh->type = inet_addr_type(entry->ip);
+	if (neigh->type != RTN_UNICAST) return -EINVAL;
+	if (in_dev->arp_parms) neigh->parms = in_dev->arp_parms;
+	neigh->ops = &clip_neigh_ops;
+	neigh->output = neigh->nud_state & NUD_VALID ?
+	    neigh->ops->connected_output : neigh->ops->output;
+	entry->neigh = neigh;
+	entry->vccs = NULL;
+	entry->expires = jiffies-1;
+	return 0;
+}
+
+static u32 clip_hash(const void *pkey, const struct net_device *dev)
+{
+	u32 hash_val;
+
+	hash_val = *(u32*)pkey;
+	hash_val ^= (hash_val>>16);
+	hash_val ^= hash_val>>8;
+	hash_val ^= hash_val>>3;
+	hash_val = (hash_val^dev->ifindex)&NEIGH_HASHMASK;
+
+	return hash_val;
+}
+
+
+struct neigh_table clip_tbl = {
+	NULL,			/* next */
+	AF_INET,		/* family */
+	sizeof(struct neighbour)+sizeof(struct atmarp_entry), /* entry_size */
+	4,			/* key_len */
+	clip_hash,
+	clip_constructor,	/* constructor */
+	NULL,			/* pconstructor */
+	NULL,			/* pdestructor */
+	NULL,			/* proxy_redo */
+	"clip_arp_cache",
+	{			/* neigh_parms */
+		NULL,		/* next */
+		NULL,		/* neigh_setup */
+		&clip_tbl,	/* tbl */
+		0,		/* entries */
+		NULL,		/* priv */
+		NULL,		/* sysctl_table */
+		30*HZ,		/* base_reachable_time */
+		1*HZ,		/* retrans_time */
+		60*HZ,		/* gc_staletime */
+		30*HZ,		/* reachable_time */
+		5*HZ,		/* delay_probe_time */
+		3,		/* queue_len */
+		3,		/* ucast_probes */
+		0,		/* app_probes */
+		3,		/* mcast_probes */
+		1*HZ,		/* anycast_delay */
+		(8*HZ)/10,	/* proxy_delay */
+		1*HZ,		/* proxy_qlen */
+		64		/* locktime */
+	},
+	30*HZ,128,512,1024	/* copied from ARP ... */
+};
+
+
+/* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
+
+/*
+ * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
+ * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
+ * don't increment the usage count. This is used to create entries in
+ * clip_setentry.
+ */
+
+
+int clip_encap(struct atm_vcc *vcc,int mode)
+{
+	CLIP_VCC(vcc)->encap = mode;
+	return 0;
+}
+
+
+static int clip_start_xmit(struct sk_buff *skb,struct net_device *dev)
+{
+	struct atmarp_entry *entry;
+
+	DPRINTK("clip_start_xmit (skb %p)\n",skb);
+	if (!skb->dst) {
+		printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");
+		dev_kfree_skb(skb);
+		return 0;
+	}
+	if (!skb->dst->neighbour) {
+#if 0
+		skb->dst->neighbour = clip_find_neighbour(skb->dst,1);
+		if (!skb->dst->neighbour) {
+			dev_kfree_skb(skb); /* lost that one */
+			PRIV(dev)->stats.tx_dropped++;
+			return 0;
+		}
+#endif
+printk("clip_start_xmit: NO NEIGHBOUR !\n");
+return 0;
+	}
+	entry = NEIGH2ENTRY(skb->dst->neighbour);
+	if (!entry->vccs) {
+		if (time_after(jiffies, entry->expires)) {
+			/* should be resolved */
+			entry->expires = jiffies+ATMARP_RETRY_DELAY*HZ;
+			to_atmarpd(act_need,PRIV(dev)->number,entry->ip);
+		}
+		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
+			skb_queue_tail(&entry->neigh->arp_queue,skb);
+		else {
+			dev_kfree_skb(skb);
+			PRIV(dev)->stats.tx_dropped++;
+		}
+		return 0;
+	}
+	DPRINTK("neigh %p, vccs %p\n",entry,entry->vccs);
+	ATM_SKB(skb)->vcc = entry->vccs->vcc;
+	DPRINTK("using neighbour %p, vcc %p\n",skb->dst->neighbour,
+	    ATM_SKB(skb)->vcc);
+	if (entry->vccs->encap) {
+		void *here;
+
+		here = skb_push(skb,RFC1483LLC_LEN);
+		memcpy(here,llc_oui,sizeof(llc_oui));
+		((u16 *) here)[3] = skb->protocol;
+	}
+	atomic_add(skb->truesize,&ATM_SKB(skb)->vcc->tx_inuse);
+	ATM_SKB(skb)->iovcnt = 0;
+	ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
+	entry->vccs->last_use = jiffies;
+	DPRINTK("atm_skb(%p)->vcc(%p)->dev(%p)\n",skb,ATM_SKB(skb)->vcc,
+	    ATM_SKB(skb)->vcc->dev);
+	(void) ATM_SKB(skb)->vcc->dev->ops->send(ATM_SKB(skb)->vcc,skb);
+	PRIV(dev)->stats.tx_packets++;
+	return 0;
+}
+
+
+static struct enet_statistics *clip_get_stats(struct net_device *dev)
+{
+	return &PRIV(dev)->stats;
+}
+
+
+int clip_mkip(struct atm_vcc *vcc,int timeout)
+{
+	struct clip_vcc *clip_vcc;
+	struct sk_buff_head copy;
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	if (!vcc->push) return -EBADFD;
+	clip_vcc = kmalloc(sizeof(struct clip_vcc),GFP_KERNEL);
+	if (!clip_vcc) return -ENOMEM;
+	DPRINTK("mkip clip_vcc %p vcc %p\n",clip_vcc,vcc);
+	clip_vcc->vcc = vcc;
+	vcc->user_back = clip_vcc;
+	clip_vcc->entry = NULL;
+	clip_vcc->encap = 1;
+	clip_vcc->last_use = jiffies;
+	clip_vcc->idle_timeout = timeout*HZ;
+	clip_vcc->old_push = vcc->push;
+	save_flags(flags);
+	cli();
+	vcc->push = clip_push;
+	skb_migrate(&vcc->recvq,&copy);
+	restore_flags(flags);
+	/* re-process everything received between connection setup and MKIP */
+	while ((skb = skb_dequeue(&copy)))
+		if (!clip_devs) {
+			atm_return(vcc,skb->truesize);
+			kfree_skb(skb);
+		}
+		else {
+			clip_push(vcc,skb);
+			PRIV(skb->dev)->stats.rx_packets--;
+		}
+	return 0;
+}
+
+
+int clip_setentry(struct atm_vcc *vcc,u32 ip)
+{
+	struct neighbour *neigh;
+	struct atmarp_entry *entry;
+	int error;
+	struct clip_vcc *clip_vcc;
+	struct rtable *rt;
+
+	if (vcc->push != clip_push) {
+		printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");
+		return -EBADF;
+	}
+	clip_vcc = CLIP_VCC(vcc);
+	if (!ip) {
+		if (!clip_vcc->entry) {
+			printk(KERN_ERR "hiding hidden ATMARP entry\n");
+			return 0;
+		}
+		DPRINTK("setentry: remove\n");
+		unlink_clip_vcc(clip_vcc);
+		return 0;
+	}
+	error = ip_route_output(&rt,ip,0,1,0);
+	if (error) return error;
+	neigh = __neigh_lookup(&clip_tbl,&ip,rt->u.dst.dev,1);
+	ip_rt_put(rt);
+	if (!neigh)
+		return -ENOMEM;
+	entry = NEIGH2ENTRY(neigh);
+	if (entry != clip_vcc->entry) {
+		if (!clip_vcc->entry) DPRINTK("setentry: add\n");
+		else {
+			DPRINTK("setentry: update\n");
+			unlink_clip_vcc(clip_vcc);
+		}
+		link_vcc(clip_vcc,entry);
+	}
+	error = neigh_update(neigh,llc_oui,NUD_PERMANENT,1,0);
+	neigh_release(neigh);
+	return error;
+}
+
+
+static int clip_init(struct net_device *dev)
+{
+	DPRINTK("clip_init %s\n",dev->name);
+	dev->hard_start_xmit = clip_start_xmit;
+	/* sg_xmit ... */
+	dev->hard_header = NULL;
+	dev->rebuild_header = NULL;
+	dev->set_mac_address = NULL;
+	dev->hard_header_parse = NULL;
+	dev->hard_header_cache = NULL;
+	dev->header_cache_update = NULL;
+	dev->change_mtu = NULL;
+	dev->do_ioctl = NULL;
+	dev->get_stats = clip_get_stats;
+	dev->type = ARPHRD_ATM;
+	dev->hard_header_len = RFC1483LLC_LEN;
+	dev->mtu = RFC1626_MTU;
+	dev->addr_len = 0;
+	dev->tx_queue_len = 0;
+	dev->flags = 0;
+	dev_init_buffers(dev); /* is this ever supposed to be used ? */
+	return 0;
+}
+
+
+int clip_create(int number)
+{
+	struct net_device *dev;
+	int error;
+
+	if (number != -1) {
+		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
+			if (PRIV(dev)->number == number) return -EEXIST;
+	}
+	else {
+		number = 0;
+		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
+			if (PRIV(dev)->number >= number)
+				number = PRIV(dev)->number+1;
+	}
+	dev = kmalloc(sizeof(struct net_device)+sizeof(struct clip_priv),
+	    GFP_KERNEL); 
+	if (!dev) return -ENOMEM;
+	memset(dev,0,sizeof(struct net_device)+sizeof(struct clip_priv));
+	dev->name = PRIV(dev)->name;
+	sprintf(dev->name,"atm%d",number);
+	dev->init = clip_init;
+	PRIV(dev)->number = number;
+	error = register_netdev(dev);
+	if (error) {
+		kfree(dev);
+		return error;
+	}
+	PRIV(dev)->next = clip_devs;
+	clip_devs = dev;
+	DPRINTK("registered (net:%s)\n",dev->name);
+	return number;
+}
+
+
+static int clip_device_event(struct notifier_block *this,unsigned long event,
+    void *dev)
+{
+	/* ignore non-CLIP devices */
+	if (((struct net_device *) dev)->type != ARPHRD_ATM ||
+	    ((struct net_device *) dev)->init != clip_init)
+		return NOTIFY_DONE;
+	switch (event) {
+		case NETDEV_UP:
+			DPRINTK("clip_device_event NETDEV_UP\n");
+			(void) to_atmarpd(act_up,PRIV(dev)->number,0);
+			break;
+		case NETDEV_DOWN:
+			DPRINTK("clip_device_event NETDEV_DOWN\n");
+			(void) to_atmarpd(act_down,PRIV(dev)->number,0);
+			break;
+		case NETDEV_CHANGE:
+		case NETDEV_CHANGEMTU:
+			DPRINTK("clip_device_event NETDEV_CHANGE*\n");
+			(void) to_atmarpd(act_change,PRIV(dev)->number,0);
+			break;
+		case NETDEV_REBOOT:
+		case NETDEV_REGISTER:
+			DPRINTK("clip_device_event %ld\n",event);
+			/* ignore */
+			break;
+		default:
+			printk(KERN_WARNING "clip_device_event: unknown event "
+			    "%ld\n",event);
+			break;
+	}
+	return NOTIFY_DONE;
+}
+
+
+static int clip_inet_event(struct notifier_block *this,unsigned long event,
+    void *ifa)
+{
+	struct in_device *in_dev;
+
+	in_dev = ((struct in_ifaddr *) ifa)->ifa_dev;
+	if (!in_dev || !in_dev->dev) {
+		printk(KERN_WARNING "clip_inet_event: no device\n");
+		return NOTIFY_DONE;
+	}
+	/*
+	 * Transitions are of the down-change-up type, so it's sufficient to
+	 * handle the change on up.
+	 */
+	if (event != NETDEV_UP) return NOTIFY_DONE;
+	return clip_device_event(this,NETDEV_CHANGE,in_dev->dev);
+}
+
+
+static struct notifier_block clip_dev_notifier = {
+	clip_device_event,
+	NULL,
+	0
+};
+
+
+
+static struct notifier_block clip_inet_notifier = {
+	clip_inet_event,
+	NULL,
+	0
+};
+
+
+
+static void atmarpd_close(struct atm_vcc *vcc)
+{
+	struct sk_buff *skb;
+
+	DPRINTK("atmarpd_close\n");
+	atmarpd = NULL; /* assumed to be atomic */
+	barrier();
+	unregister_inetaddr_notifier(&clip_inet_notifier);
+	unregister_netdevice_notifier(&clip_dev_notifier);
+	if (skb_peek(&vcc->recvq))
+		printk(KERN_ERR "atmarpd_close: closing with requests "
+		    "pending\n");
+	while ((skb = skb_dequeue(&vcc->recvq))) kfree_skb(skb);
+	DPRINTK("(done)\n");
+}
+
+
+static struct atmdev_ops atmarpd_dev_ops = {
+	NULL,		/* no dev_close */
+	NULL,		/* no open */
+	atmarpd_close,	/* close */
+	NULL,		/* no ioctl */
+	NULL,		/* no getsockopt */
+	NULL,		/* no setsockopt */
+	NULL,		/* send */
+	NULL,		/* no sg_send */
+	NULL,		/* no send_oam */
+	NULL,		/* no phy_put */
+	NULL,		/* no phy_get */
+	NULL,		/* no feedback */
+	NULL,		/* no change_qos */
+	NULL		/* no free_rx_skb */
+};
+
+
+static struct atm_dev atmarpd_dev = {
+	&atmarpd_dev_ops,
+	NULL,		/* no PHY */
+	"arpd",		/* type */
+	999,		/* dummy device number */
+	NULL,NULL,	/* pretend not to have any VCCs */
+	NULL,NULL,	/* no data */
+	0,		/* no flags */
+	NULL,		/* no local address */
+	{ 0 }		/* no ESI, no statistics */
+};
+
+
+int atm_init_atmarp(struct atm_vcc *vcc)
+{
+	struct net_device *dev;
+
+	if (atmarpd) return -EADDRINUSE;
+	if (start_timer) {
+		start_timer = 0;
+		idle_timer.expires = jiffies+CLIP_CHECK_INTERVAL*HZ;
+		idle_timer.function = idle_timer_check;
+		add_timer(&idle_timer);
+	}
+	atmarpd = vcc;
+	vcc->flags |= ATM_VF_READY | ATM_VF_META;
+	    /* allow replies and avoid getting closed if signaling dies */
+	bind_vcc(vcc,&atmarpd_dev);
+	vcc->push = NULL;
+	vcc->pop = NULL; /* crash */
+	vcc->push_oam = NULL; /* crash */
+	if (register_netdevice_notifier(&clip_dev_notifier))
+		printk(KERN_ERR "register_netdevice_notifier failed\n");
+	if (register_inetaddr_notifier(&clip_inet_notifier))
+		printk(KERN_ERR "register_inetaddr_notifier failed\n");
+	for (dev = clip_devs; dev; dev = PRIV(dev)->next)
+		if (dev->flags & IFF_UP)
+			(void) to_atmarpd(act_up,PRIV(dev)->number,0);
+	return 0;
+}