xref: /linux/net/atm/clip.c (revision fd639726bf15fca8ee1a00dce8e0096d0ad9bd18)
1 /* net/atm/clip.c - RFC1577 Classical IP over ATM */
2 
3 /* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
4 
5 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
6 
7 #include <linux/string.h>
8 #include <linux/errno.h>
9 #include <linux/kernel.h> /* for UINT_MAX */
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/netdevice.h>
13 #include <linux/skbuff.h>
14 #include <linux/wait.h>
15 #include <linux/timer.h>
16 #include <linux/if_arp.h> /* for some manifest constants */
17 #include <linux/notifier.h>
18 #include <linux/atm.h>
19 #include <linux/atmdev.h>
20 #include <linux/atmclip.h>
21 #include <linux/atmarp.h>
22 #include <linux/capability.h>
23 #include <linux/ip.h> /* for net/route.h */
24 #include <linux/in.h> /* for struct sockaddr_in */
25 #include <linux/if.h> /* for IFF_UP */
26 #include <linux/inetdevice.h>
27 #include <linux/bitops.h>
28 #include <linux/poison.h>
29 #include <linux/proc_fs.h>
30 #include <linux/seq_file.h>
31 #include <linux/rcupdate.h>
32 #include <linux/jhash.h>
33 #include <linux/slab.h>
34 #include <net/route.h> /* for struct rtable and routing */
35 #include <net/icmp.h> /* icmp_send */
36 #include <net/arp.h>
37 #include <linux/param.h> /* for HZ */
38 #include <linux/uaccess.h>
39 #include <asm/byteorder.h> /* for htons etc. */
40 #include <linux/atomic.h>
41 
42 #include "common.h"
43 #include "resources.h"
44 #include <net/atmclip.h>
45 
46 static struct net_device *clip_devs;
47 static struct atm_vcc *atmarpd;
48 static struct timer_list idle_timer;
49 static const struct neigh_ops clip_neigh_ops;
50 
51 static int to_atmarpd(enum atmarp_ctrl_type type, int itf, __be32 ip)
52 {
53 	struct sock *sk;
54 	struct atmarp_ctrl *ctrl;
55 	struct sk_buff *skb;
56 
57 	pr_debug("(%d)\n", type);
58 	if (!atmarpd)
59 		return -EUNATCH;
60 	skb = alloc_skb(sizeof(struct atmarp_ctrl), GFP_ATOMIC);
61 	if (!skb)
62 		return -ENOMEM;
63 	ctrl = skb_put(skb, sizeof(struct atmarp_ctrl));
64 	ctrl->type = type;
65 	ctrl->itf_num = itf;
66 	ctrl->ip = ip;
67 	atm_force_charge(atmarpd, skb->truesize);
68 
69 	sk = sk_atm(atmarpd);
70 	skb_queue_tail(&sk->sk_receive_queue, skb);
71 	sk->sk_data_ready(sk);
72 	return 0;
73 }
74 
75 static void link_vcc(struct clip_vcc *clip_vcc, struct atmarp_entry *entry)
76 {
77 	pr_debug("%p to entry %p (neigh %p)\n", clip_vcc, entry, entry->neigh);
78 	clip_vcc->entry = entry;
79 	clip_vcc->xoff = 0;	/* @@@ may overrun buffer by one packet */
80 	clip_vcc->next = entry->vccs;
81 	entry->vccs = clip_vcc;
82 	entry->neigh->used = jiffies;
83 }
84 
85 static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
86 {
87 	struct atmarp_entry *entry = clip_vcc->entry;
88 	struct clip_vcc **walk;
89 
90 	if (!entry) {
91 		pr_crit("!clip_vcc->entry (clip_vcc %p)\n", clip_vcc);
92 		return;
93 	}
94 	netif_tx_lock_bh(entry->neigh->dev);	/* block clip_start_xmit() */
95 	entry->neigh->used = jiffies;
96 	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
97 		if (*walk == clip_vcc) {
98 			int error;
99 
100 			*walk = clip_vcc->next;	/* atomic */
101 			clip_vcc->entry = NULL;
102 			if (clip_vcc->xoff)
103 				netif_wake_queue(entry->neigh->dev);
104 			if (entry->vccs)
105 				goto out;
106 			entry->expires = jiffies - 1;
107 			/* force resolution or expiration */
108 			error = neigh_update(entry->neigh, NULL, NUD_NONE,
109 					     NEIGH_UPDATE_F_ADMIN, 0);
110 			if (error)
111 				pr_crit("neigh_update failed with %d\n", error);
112 			goto out;
113 		}
114 	pr_crit("ATMARP: failed (entry %p, vcc 0x%p)\n", entry, clip_vcc);
115 out:
116 	netif_tx_unlock_bh(entry->neigh->dev);
117 }
118 
119 /* The neighbour entry n->lock is held. */
120 static int neigh_check_cb(struct neighbour *n)
121 {
122 	struct atmarp_entry *entry = neighbour_priv(n);
123 	struct clip_vcc *cv;
124 
125 	if (n->ops != &clip_neigh_ops)
126 		return 0;
127 	for (cv = entry->vccs; cv; cv = cv->next) {
128 		unsigned long exp = cv->last_use + cv->idle_timeout;
129 
130 		if (cv->idle_timeout && time_after(jiffies, exp)) {
131 			pr_debug("releasing vcc %p->%p of entry %p\n",
132 				 cv, cv->vcc, entry);
133 			vcc_release_async(cv->vcc, -ETIMEDOUT);
134 		}
135 	}
136 
137 	if (entry->vccs || time_before(jiffies, entry->expires))
138 		return 0;
139 
140 	if (refcount_read(&n->refcnt) > 1) {
141 		struct sk_buff *skb;
142 
143 		pr_debug("destruction postponed with ref %d\n",
144 			 refcount_read(&n->refcnt));
145 
146 		while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
147 			dev_kfree_skb(skb);
148 
149 		return 0;
150 	}
151 
152 	pr_debug("expired neigh %p\n", n);
153 	return 1;
154 }
155 
156 static void idle_timer_check(struct timer_list *unused)
157 {
158 	write_lock(&arp_tbl.lock);
159 	__neigh_for_each_release(&arp_tbl, neigh_check_cb);
160 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
161 	write_unlock(&arp_tbl.lock);
162 }
163 
164 static int clip_arp_rcv(struct sk_buff *skb)
165 {
166 	struct atm_vcc *vcc;
167 
168 	pr_debug("\n");
169 	vcc = ATM_SKB(skb)->vcc;
170 	if (!vcc || !atm_charge(vcc, skb->truesize)) {
171 		dev_kfree_skb_any(skb);
172 		return 0;
173 	}
174 	pr_debug("pushing to %p\n", vcc);
175 	pr_debug("using %p\n", CLIP_VCC(vcc)->old_push);
176 	CLIP_VCC(vcc)->old_push(vcc, skb);
177 	return 0;
178 }
179 
180 static const unsigned char llc_oui[] = {
181 	0xaa,	/* DSAP: non-ISO */
182 	0xaa,	/* SSAP: non-ISO */
183 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
184 	0x00,	/* OUI: EtherType */
185 	0x00,
186 	0x00
187 };
188 
189 static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
190 {
191 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
192 
193 	pr_debug("\n");
194 
195 	if (!clip_devs) {
196 		atm_return(vcc, skb->truesize);
197 		kfree_skb(skb);
198 		return;
199 	}
200 
201 	if (!skb) {
202 		pr_debug("removing VCC %p\n", clip_vcc);
203 		if (clip_vcc->entry)
204 			unlink_clip_vcc(clip_vcc);
205 		clip_vcc->old_push(vcc, NULL);	/* pass on the bad news */
206 		kfree(clip_vcc);
207 		return;
208 	}
209 	atm_return(vcc, skb->truesize);
210 	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
211 	/* clip_vcc->entry == NULL if we don't have an IP address yet */
212 	if (!skb->dev) {
213 		dev_kfree_skb_any(skb);
214 		return;
215 	}
216 	ATM_SKB(skb)->vcc = vcc;
217 	skb_reset_mac_header(skb);
218 	if (!clip_vcc->encap ||
219 	    skb->len < RFC1483LLC_LEN ||
220 	    memcmp(skb->data, llc_oui, sizeof(llc_oui)))
221 		skb->protocol = htons(ETH_P_IP);
222 	else {
223 		skb->protocol = ((__be16 *)skb->data)[3];
224 		skb_pull(skb, RFC1483LLC_LEN);
225 		if (skb->protocol == htons(ETH_P_ARP)) {
226 			skb->dev->stats.rx_packets++;
227 			skb->dev->stats.rx_bytes += skb->len;
228 			clip_arp_rcv(skb);
229 			return;
230 		}
231 	}
232 	clip_vcc->last_use = jiffies;
233 	skb->dev->stats.rx_packets++;
234 	skb->dev->stats.rx_bytes += skb->len;
235 	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
236 	netif_rx(skb);
237 }
238 
239 /*
240  * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
241  * clip_pop is atomic with respect to the critical section in clip_start_xmit.
242  */
243 
244 static void clip_pop(struct atm_vcc *vcc, struct sk_buff *skb)
245 {
246 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
247 	struct net_device *dev = skb->dev;
248 	int old;
249 	unsigned long flags;
250 
251 	pr_debug("(vcc %p)\n", vcc);
252 	clip_vcc->old_pop(vcc, skb);
253 	/* skb->dev == NULL in outbound ARP packets */
254 	if (!dev)
255 		return;
256 	spin_lock_irqsave(&PRIV(dev)->xoff_lock, flags);
257 	if (atm_may_send(vcc, 0)) {
258 		old = xchg(&clip_vcc->xoff, 0);
259 		if (old)
260 			netif_wake_queue(dev);
261 	}
262 	spin_unlock_irqrestore(&PRIV(dev)->xoff_lock, flags);
263 }
264 
265 static void clip_neigh_solicit(struct neighbour *neigh, struct sk_buff *skb)
266 {
267 	__be32 *ip = (__be32 *) neigh->primary_key;
268 
269 	pr_debug("(neigh %p, skb %p)\n", neigh, skb);
270 	to_atmarpd(act_need, PRIV(neigh->dev)->number, *ip);
271 }
272 
273 static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
274 {
275 #ifndef CONFIG_ATM_CLIP_NO_ICMP
276 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
277 #endif
278 	kfree_skb(skb);
279 }
280 
281 static const struct neigh_ops clip_neigh_ops = {
282 	.family =		AF_INET,
283 	.solicit =		clip_neigh_solicit,
284 	.error_report =		clip_neigh_error,
285 	.output =		neigh_direct_output,
286 	.connected_output =	neigh_direct_output,
287 };
288 
289 static int clip_constructor(struct net_device *dev, struct neighbour *neigh)
290 {
291 	struct atmarp_entry *entry = neighbour_priv(neigh);
292 
293 	if (neigh->tbl->family != AF_INET)
294 		return -EINVAL;
295 
296 	if (neigh->type != RTN_UNICAST)
297 		return -EINVAL;
298 
299 	neigh->nud_state = NUD_NONE;
300 	neigh->ops = &clip_neigh_ops;
301 	neigh->output = neigh->ops->output;
302 	entry->neigh = neigh;
303 	entry->vccs = NULL;
304 	entry->expires = jiffies - 1;
305 
306 	return 0;
307 }
308 
309 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
310 
311 /*
312  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
313  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
314  * don't increment the usage count. This is used to create entries in
315  * clip_setentry.
316  */
317 
318 static int clip_encap(struct atm_vcc *vcc, int mode)
319 {
320 	if (!CLIP_VCC(vcc))
321 		return -EBADFD;
322 
323 	CLIP_VCC(vcc)->encap = mode;
324 	return 0;
325 }
326 
327 static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
328 				   struct net_device *dev)
329 {
330 	struct clip_priv *clip_priv = PRIV(dev);
331 	struct dst_entry *dst = skb_dst(skb);
332 	struct atmarp_entry *entry;
333 	struct neighbour *n;
334 	struct atm_vcc *vcc;
335 	struct rtable *rt;
336 	__be32 *daddr;
337 	int old;
338 	unsigned long flags;
339 
340 	pr_debug("(skb %p)\n", skb);
341 	if (!dst) {
342 		pr_err("skb_dst(skb) == NULL\n");
343 		dev_kfree_skb(skb);
344 		dev->stats.tx_dropped++;
345 		return NETDEV_TX_OK;
346 	}
347 	rt = (struct rtable *) dst;
348 	if (rt->rt_gateway)
349 		daddr = &rt->rt_gateway;
350 	else
351 		daddr = &ip_hdr(skb)->daddr;
352 	n = dst_neigh_lookup(dst, daddr);
353 	if (!n) {
354 		pr_err("NO NEIGHBOUR !\n");
355 		dev_kfree_skb(skb);
356 		dev->stats.tx_dropped++;
357 		return NETDEV_TX_OK;
358 	}
359 	entry = neighbour_priv(n);
360 	if (!entry->vccs) {
361 		if (time_after(jiffies, entry->expires)) {
362 			/* should be resolved */
363 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
364 			to_atmarpd(act_need, PRIV(dev)->number, *((__be32 *)n->primary_key));
365 		}
366 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
367 			skb_queue_tail(&entry->neigh->arp_queue, skb);
368 		else {
369 			dev_kfree_skb(skb);
370 			dev->stats.tx_dropped++;
371 		}
372 		goto out_release_neigh;
373 	}
374 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
375 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
376 	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
377 	if (entry->vccs->encap) {
378 		void *here;
379 
380 		here = skb_push(skb, RFC1483LLC_LEN);
381 		memcpy(here, llc_oui, sizeof(llc_oui));
382 		((__be16 *) here)[3] = skb->protocol;
383 	}
384 	refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
385 	ATM_SKB(skb)->atm_options = vcc->atm_options;
386 	entry->vccs->last_use = jiffies;
387 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
388 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
389 	if (old) {
390 		pr_warn("XOFF->XOFF transition\n");
391 		goto out_release_neigh;
392 	}
393 	dev->stats.tx_packets++;
394 	dev->stats.tx_bytes += skb->len;
395 	vcc->send(vcc, skb);
396 	if (atm_may_send(vcc, 0)) {
397 		entry->vccs->xoff = 0;
398 		goto out_release_neigh;
399 	}
400 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
401 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
402 	barrier();
403 	if (!entry->vccs->xoff)
404 		netif_start_queue(dev);
405 	/* Oh, we just raced with clip_pop. netif_start_queue should be
406 	   good enough, because nothing should really be asleep because
407 	   of the brief netif_stop_queue. If this isn't true or if it
408 	   changes, use netif_wake_queue instead. */
409 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
410 out_release_neigh:
411 	neigh_release(n);
412 	return NETDEV_TX_OK;
413 }
414 
415 static int clip_mkip(struct atm_vcc *vcc, int timeout)
416 {
417 	struct clip_vcc *clip_vcc;
418 
419 	if (!vcc->push)
420 		return -EBADFD;
421 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
422 	if (!clip_vcc)
423 		return -ENOMEM;
424 	pr_debug("%p vcc %p\n", clip_vcc, vcc);
425 	clip_vcc->vcc = vcc;
426 	vcc->user_back = clip_vcc;
427 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
428 	clip_vcc->entry = NULL;
429 	clip_vcc->xoff = 0;
430 	clip_vcc->encap = 1;
431 	clip_vcc->last_use = jiffies;
432 	clip_vcc->idle_timeout = timeout * HZ;
433 	clip_vcc->old_push = vcc->push;
434 	clip_vcc->old_pop = vcc->pop;
435 	vcc->push = clip_push;
436 	vcc->pop = clip_pop;
437 
438 	/* re-process everything received between connection setup and MKIP */
439 	vcc_process_recv_queue(vcc);
440 
441 	return 0;
442 }
443 
444 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
445 {
446 	struct neighbour *neigh;
447 	struct atmarp_entry *entry;
448 	int error;
449 	struct clip_vcc *clip_vcc;
450 	struct rtable *rt;
451 
452 	if (vcc->push != clip_push) {
453 		pr_warn("non-CLIP VCC\n");
454 		return -EBADF;
455 	}
456 	clip_vcc = CLIP_VCC(vcc);
457 	if (!ip) {
458 		if (!clip_vcc->entry) {
459 			pr_err("hiding hidden ATMARP entry\n");
460 			return 0;
461 		}
462 		pr_debug("remove\n");
463 		unlink_clip_vcc(clip_vcc);
464 		return 0;
465 	}
466 	rt = ip_route_output(&init_net, ip, 0, 1, 0);
467 	if (IS_ERR(rt))
468 		return PTR_ERR(rt);
469 	neigh = __neigh_lookup(&arp_tbl, &ip, rt->dst.dev, 1);
470 	ip_rt_put(rt);
471 	if (!neigh)
472 		return -ENOMEM;
473 	entry = neighbour_priv(neigh);
474 	if (entry != clip_vcc->entry) {
475 		if (!clip_vcc->entry)
476 			pr_debug("add\n");
477 		else {
478 			pr_debug("update\n");
479 			unlink_clip_vcc(clip_vcc);
480 		}
481 		link_vcc(clip_vcc, entry);
482 	}
483 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
484 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN, 0);
485 	neigh_release(neigh);
486 	return error;
487 }
488 
489 static const struct net_device_ops clip_netdev_ops = {
490 	.ndo_start_xmit		= clip_start_xmit,
491 	.ndo_neigh_construct	= clip_constructor,
492 };
493 
494 static void clip_setup(struct net_device *dev)
495 {
496 	dev->netdev_ops = &clip_netdev_ops;
497 	dev->type = ARPHRD_ATM;
498 	dev->neigh_priv_len = sizeof(struct atmarp_entry);
499 	dev->hard_header_len = RFC1483LLC_LEN;
500 	dev->mtu = RFC1626_MTU;
501 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
502 	/* When using a "real" qdisc, the qdisc determines the queue */
503 	/* length. tx_queue_len is only used for the default case, */
504 	/* without any more elaborate queuing. 100 is a reasonable */
505 	/* compromise between decent burst-tolerance and protection */
506 	/* against memory hogs. */
507 	netif_keep_dst(dev);
508 }
509 
510 static int clip_create(int number)
511 {
512 	struct net_device *dev;
513 	struct clip_priv *clip_priv;
514 	int error;
515 
516 	if (number != -1) {
517 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
518 			if (PRIV(dev)->number == number)
519 				return -EEXIST;
520 	} else {
521 		number = 0;
522 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
523 			if (PRIV(dev)->number >= number)
524 				number = PRIV(dev)->number + 1;
525 	}
526 	dev = alloc_netdev(sizeof(struct clip_priv), "", NET_NAME_UNKNOWN,
527 			   clip_setup);
528 	if (!dev)
529 		return -ENOMEM;
530 	clip_priv = PRIV(dev);
531 	sprintf(dev->name, "atm%d", number);
532 	spin_lock_init(&clip_priv->xoff_lock);
533 	clip_priv->number = number;
534 	error = register_netdev(dev);
535 	if (error) {
536 		free_netdev(dev);
537 		return error;
538 	}
539 	clip_priv->next = clip_devs;
540 	clip_devs = dev;
541 	pr_debug("registered (net:%s)\n", dev->name);
542 	return number;
543 }
544 
545 static int clip_device_event(struct notifier_block *this, unsigned long event,
546 			     void *ptr)
547 {
548 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
549 
550 	if (!net_eq(dev_net(dev), &init_net))
551 		return NOTIFY_DONE;
552 
553 	if (event == NETDEV_UNREGISTER)
554 		return NOTIFY_DONE;
555 
556 	/* ignore non-CLIP devices */
557 	if (dev->type != ARPHRD_ATM || dev->netdev_ops != &clip_netdev_ops)
558 		return NOTIFY_DONE;
559 
560 	switch (event) {
561 	case NETDEV_UP:
562 		pr_debug("NETDEV_UP\n");
563 		to_atmarpd(act_up, PRIV(dev)->number, 0);
564 		break;
565 	case NETDEV_GOING_DOWN:
566 		pr_debug("NETDEV_DOWN\n");
567 		to_atmarpd(act_down, PRIV(dev)->number, 0);
568 		break;
569 	case NETDEV_CHANGE:
570 	case NETDEV_CHANGEMTU:
571 		pr_debug("NETDEV_CHANGE*\n");
572 		to_atmarpd(act_change, PRIV(dev)->number, 0);
573 		break;
574 	}
575 	return NOTIFY_DONE;
576 }
577 
578 static int clip_inet_event(struct notifier_block *this, unsigned long event,
579 			   void *ifa)
580 {
581 	struct in_device *in_dev;
582 	struct netdev_notifier_info info;
583 
584 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
585 	/*
586 	 * Transitions are of the down-change-up type, so it's sufficient to
587 	 * handle the change on up.
588 	 */
589 	if (event != NETDEV_UP)
590 		return NOTIFY_DONE;
591 	netdev_notifier_info_init(&info, in_dev->dev);
592 	return clip_device_event(this, NETDEV_CHANGE, &info);
593 }
594 
595 static struct notifier_block clip_dev_notifier = {
596 	.notifier_call = clip_device_event,
597 };
598 
599 
600 
601 static struct notifier_block clip_inet_notifier = {
602 	.notifier_call = clip_inet_event,
603 };
604 
605 
606 
607 static void atmarpd_close(struct atm_vcc *vcc)
608 {
609 	pr_debug("\n");
610 
611 	rtnl_lock();
612 	atmarpd = NULL;
613 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
614 	rtnl_unlock();
615 
616 	pr_debug("(done)\n");
617 	module_put(THIS_MODULE);
618 }
619 
620 static const struct atmdev_ops atmarpd_dev_ops = {
621 	.close = atmarpd_close
622 };
623 
624 
625 static struct atm_dev atmarpd_dev = {
626 	.ops =			&atmarpd_dev_ops,
627 	.type =			"arpd",
628 	.number = 		999,
629 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
630 };
631 
632 
633 static int atm_init_atmarp(struct atm_vcc *vcc)
634 {
635 	rtnl_lock();
636 	if (atmarpd) {
637 		rtnl_unlock();
638 		return -EADDRINUSE;
639 	}
640 
641 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
642 
643 	atmarpd = vcc;
644 	set_bit(ATM_VF_META, &vcc->flags);
645 	set_bit(ATM_VF_READY, &vcc->flags);
646 	    /* allow replies and avoid getting closed if signaling dies */
647 	vcc->dev = &atmarpd_dev;
648 	vcc_insert_socket(sk_atm(vcc));
649 	vcc->push = NULL;
650 	vcc->pop = NULL; /* crash */
651 	vcc->push_oam = NULL; /* crash */
652 	rtnl_unlock();
653 	return 0;
654 }
655 
656 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
657 {
658 	struct atm_vcc *vcc = ATM_SD(sock);
659 	int err = 0;
660 
661 	switch (cmd) {
662 	case SIOCMKCLIP:
663 	case ATMARPD_CTRL:
664 	case ATMARP_MKIP:
665 	case ATMARP_SETENTRY:
666 	case ATMARP_ENCAP:
667 		if (!capable(CAP_NET_ADMIN))
668 			return -EPERM;
669 		break;
670 	default:
671 		return -ENOIOCTLCMD;
672 	}
673 
674 	switch (cmd) {
675 	case SIOCMKCLIP:
676 		err = clip_create(arg);
677 		break;
678 	case ATMARPD_CTRL:
679 		err = atm_init_atmarp(vcc);
680 		if (!err) {
681 			sock->state = SS_CONNECTED;
682 			__module_get(THIS_MODULE);
683 		}
684 		break;
685 	case ATMARP_MKIP:
686 		err = clip_mkip(vcc, arg);
687 		break;
688 	case ATMARP_SETENTRY:
689 		err = clip_setentry(vcc, (__force __be32)arg);
690 		break;
691 	case ATMARP_ENCAP:
692 		err = clip_encap(vcc, arg);
693 		break;
694 	}
695 	return err;
696 }
697 
698 static struct atm_ioctl clip_ioctl_ops = {
699 	.owner = THIS_MODULE,
700 	.ioctl = clip_ioctl,
701 };
702 
703 #ifdef CONFIG_PROC_FS
704 
705 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
706 {
707 	static int code[] = { 1, 2, 10, 6, 1, 0 };
708 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
709 
710 	if (*addr->sas_addr.pub) {
711 		seq_printf(seq, "%s", addr->sas_addr.pub);
712 		if (*addr->sas_addr.prv)
713 			seq_putc(seq, '+');
714 	} else if (!*addr->sas_addr.prv) {
715 		seq_printf(seq, "%s", "(none)");
716 		return;
717 	}
718 	if (*addr->sas_addr.prv) {
719 		unsigned char *prv = addr->sas_addr.prv;
720 		int *fields;
721 		int i, j;
722 
723 		fields = *prv == ATM_AFI_E164 ? e164 : code;
724 		for (i = 0; fields[i]; i++) {
725 			for (j = fields[i]; j; j--)
726 				seq_printf(seq, "%02X", *prv++);
727 			if (fields[i + 1])
728 				seq_putc(seq, '.');
729 		}
730 	}
731 }
732 
733 /* This means the neighbour entry has no attached VCC objects. */
734 #define SEQ_NO_VCC_TOKEN	((void *) 2)
735 
736 static void atmarp_info(struct seq_file *seq, struct neighbour *n,
737 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
738 {
739 	struct net_device *dev = n->dev;
740 	unsigned long exp;
741 	char buf[17];
742 	int svc, llc, off;
743 
744 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
745 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
746 
747 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
748 
749 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
750 		exp = entry->neigh->used;
751 	else
752 		exp = clip_vcc->last_use;
753 
754 	exp = (jiffies - exp) / HZ;
755 
756 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
757 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
758 
759 	off = scnprintf(buf, sizeof(buf) - 1, "%pI4", n->primary_key);
760 	while (off < 16)
761 		buf[off++] = ' ';
762 	buf[off] = '\0';
763 	seq_printf(seq, "%s", buf);
764 
765 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
766 		if (time_before(jiffies, entry->expires))
767 			seq_printf(seq, "(resolving)\n");
768 		else
769 			seq_printf(seq, "(expired, ref %d)\n",
770 				   refcount_read(&entry->neigh->refcnt));
771 	} else if (!svc) {
772 		seq_printf(seq, "%d.%d.%d\n",
773 			   clip_vcc->vcc->dev->number,
774 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
775 	} else {
776 		svc_addr(seq, &clip_vcc->vcc->remote);
777 		seq_putc(seq, '\n');
778 	}
779 }
780 
781 struct clip_seq_state {
782 	/* This member must be first. */
783 	struct neigh_seq_state ns;
784 
785 	/* Local to clip specific iteration. */
786 	struct clip_vcc *vcc;
787 };
788 
789 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
790 					  struct clip_vcc *curr)
791 {
792 	if (!curr) {
793 		curr = e->vccs;
794 		if (!curr)
795 			return SEQ_NO_VCC_TOKEN;
796 		return curr;
797 	}
798 	if (curr == SEQ_NO_VCC_TOKEN)
799 		return NULL;
800 
801 	curr = curr->next;
802 
803 	return curr;
804 }
805 
806 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
807 			       struct atmarp_entry *e, loff_t * pos)
808 {
809 	struct clip_vcc *vcc = state->vcc;
810 
811 	vcc = clip_seq_next_vcc(e, vcc);
812 	if (vcc && pos != NULL) {
813 		while (*pos) {
814 			vcc = clip_seq_next_vcc(e, vcc);
815 			if (!vcc)
816 				break;
817 			--(*pos);
818 		}
819 	}
820 	state->vcc = vcc;
821 
822 	return vcc;
823 }
824 
825 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
826 			       struct neighbour *n, loff_t * pos)
827 {
828 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
829 
830 	if (n->dev->type != ARPHRD_ATM)
831 		return NULL;
832 
833 	return clip_seq_vcc_walk(state, neighbour_priv(n), pos);
834 }
835 
836 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
837 {
838 	struct clip_seq_state *state = seq->private;
839 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
840 	return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_NEIGH_ONLY);
841 }
842 
843 static int clip_seq_show(struct seq_file *seq, void *v)
844 {
845 	static char atm_arp_banner[] =
846 	    "IPitf TypeEncp Idle IP address      ATM address\n";
847 
848 	if (v == SEQ_START_TOKEN) {
849 		seq_puts(seq, atm_arp_banner);
850 	} else {
851 		struct clip_seq_state *state = seq->private;
852 		struct clip_vcc *vcc = state->vcc;
853 		struct neighbour *n = v;
854 
855 		atmarp_info(seq, n, neighbour_priv(n), vcc);
856 	}
857 	return 0;
858 }
859 
860 static const struct seq_operations arp_seq_ops = {
861 	.start	= clip_seq_start,
862 	.next	= neigh_seq_next,
863 	.stop	= neigh_seq_stop,
864 	.show	= clip_seq_show,
865 };
866 
867 static int arp_seq_open(struct inode *inode, struct file *file)
868 {
869 	return seq_open_net(inode, file, &arp_seq_ops,
870 			    sizeof(struct clip_seq_state));
871 }
872 
873 static const struct file_operations arp_seq_fops = {
874 	.open		= arp_seq_open,
875 	.read		= seq_read,
876 	.llseek		= seq_lseek,
877 	.release	= seq_release_net,
878 	.owner		= THIS_MODULE
879 };
880 #endif
881 
882 static void atm_clip_exit_noproc(void);
883 
884 static int __init atm_clip_init(void)
885 {
886 	register_atm_ioctl(&clip_ioctl_ops);
887 	register_netdevice_notifier(&clip_dev_notifier);
888 	register_inetaddr_notifier(&clip_inet_notifier);
889 
890 	timer_setup(&idle_timer, idle_timer_check, 0);
891 
892 #ifdef CONFIG_PROC_FS
893 	{
894 		struct proc_dir_entry *p;
895 
896 		p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
897 		if (!p) {
898 			pr_err("Unable to initialize /proc/net/atm/arp\n");
899 			atm_clip_exit_noproc();
900 			return -ENOMEM;
901 		}
902 	}
903 #endif
904 
905 	return 0;
906 }
907 
908 static void atm_clip_exit_noproc(void)
909 {
910 	struct net_device *dev, *next;
911 
912 	unregister_inetaddr_notifier(&clip_inet_notifier);
913 	unregister_netdevice_notifier(&clip_dev_notifier);
914 
915 	deregister_atm_ioctl(&clip_ioctl_ops);
916 
917 	/* First, stop the idle timer, so it stops banging
918 	 * on the table.
919 	 */
920 	del_timer_sync(&idle_timer);
921 
922 	dev = clip_devs;
923 	while (dev) {
924 		next = PRIV(dev)->next;
925 		unregister_netdev(dev);
926 		free_netdev(dev);
927 		dev = next;
928 	}
929 }
930 
931 static void __exit atm_clip_exit(void)
932 {
933 	remove_proc_entry("arp", atm_proc_root);
934 
935 	atm_clip_exit_noproc();
936 }
937 
938 module_init(atm_clip_init);
939 module_exit(atm_clip_exit);
940 MODULE_AUTHOR("Werner Almesberger");
941 MODULE_DESCRIPTION("Classical/IP over ATM interface");
942 MODULE_LICENSE("GPL");
943