xref: /openbmc/linux/net/atm/clip.c (revision b5266ea6)
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 <asm/system.h> /* save/restore_flags */
41 #include <linux/atomic.h>
42 
43 #include "common.h"
44 #include "resources.h"
45 #include <net/atmclip.h>
46 
47 static struct net_device *clip_devs;
48 static struct atm_vcc *atmarpd;
49 static struct neigh_table clip_tbl;
50 static struct timer_list idle_timer;
51 
52 static int to_atmarpd(enum atmarp_ctrl_type type, int itf, __be32 ip)
53 {
54 	struct sock *sk;
55 	struct atmarp_ctrl *ctrl;
56 	struct sk_buff *skb;
57 
58 	pr_debug("(%d)\n", type);
59 	if (!atmarpd)
60 		return -EUNATCH;
61 	skb = alloc_skb(sizeof(struct atmarp_ctrl), GFP_ATOMIC);
62 	if (!skb)
63 		return -ENOMEM;
64 	ctrl = (struct atmarp_ctrl *)skb_put(skb, sizeof(struct atmarp_ctrl));
65 	ctrl->type = type;
66 	ctrl->itf_num = itf;
67 	ctrl->ip = ip;
68 	atm_force_charge(atmarpd, skb->truesize);
69 
70 	sk = sk_atm(atmarpd);
71 	skb_queue_tail(&sk->sk_receive_queue, skb);
72 	sk->sk_data_ready(sk, skb->len);
73 	return 0;
74 }
75 
76 static void link_vcc(struct clip_vcc *clip_vcc, struct atmarp_entry *entry)
77 {
78 	pr_debug("%p to entry %p (neigh %p)\n", clip_vcc, entry, entry->neigh);
79 	clip_vcc->entry = entry;
80 	clip_vcc->xoff = 0;	/* @@@ may overrun buffer by one packet */
81 	clip_vcc->next = entry->vccs;
82 	entry->vccs = clip_vcc;
83 	entry->neigh->used = jiffies;
84 }
85 
86 static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
87 {
88 	struct atmarp_entry *entry = clip_vcc->entry;
89 	struct clip_vcc **walk;
90 
91 	if (!entry) {
92 		pr_crit("!clip_vcc->entry (clip_vcc %p)\n", clip_vcc);
93 		return;
94 	}
95 	netif_tx_lock_bh(entry->neigh->dev);	/* block clip_start_xmit() */
96 	entry->neigh->used = jiffies;
97 	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
98 		if (*walk == clip_vcc) {
99 			int error;
100 
101 			*walk = clip_vcc->next;	/* atomic */
102 			clip_vcc->entry = NULL;
103 			if (clip_vcc->xoff)
104 				netif_wake_queue(entry->neigh->dev);
105 			if (entry->vccs)
106 				goto out;
107 			entry->expires = jiffies - 1;
108 			/* force resolution or expiration */
109 			error = neigh_update(entry->neigh, NULL, NUD_NONE,
110 					     NEIGH_UPDATE_F_ADMIN);
111 			if (error)
112 				pr_crit("neigh_update failed with %d\n", error);
113 			goto out;
114 		}
115 	pr_crit("ATMARP: failed (entry %p, vcc 0x%p)\n", entry, clip_vcc);
116 out:
117 	netif_tx_unlock_bh(entry->neigh->dev);
118 }
119 
120 /* The neighbour entry n->lock is held. */
121 static int neigh_check_cb(struct neighbour *n)
122 {
123 	struct atmarp_entry *entry = neighbour_priv(n);
124 	struct clip_vcc *cv;
125 
126 	for (cv = entry->vccs; cv; cv = cv->next) {
127 		unsigned long exp = cv->last_use + cv->idle_timeout;
128 
129 		if (cv->idle_timeout && time_after(jiffies, exp)) {
130 			pr_debug("releasing vcc %p->%p of entry %p\n",
131 				 cv, cv->vcc, entry);
132 			vcc_release_async(cv->vcc, -ETIMEDOUT);
133 		}
134 	}
135 
136 	if (entry->vccs || time_before(jiffies, entry->expires))
137 		return 0;
138 
139 	if (atomic_read(&n->refcnt) > 1) {
140 		struct sk_buff *skb;
141 
142 		pr_debug("destruction postponed with ref %d\n",
143 			 atomic_read(&n->refcnt));
144 
145 		while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
146 			dev_kfree_skb(skb);
147 
148 		return 0;
149 	}
150 
151 	pr_debug("expired neigh %p\n", n);
152 	return 1;
153 }
154 
155 static void idle_timer_check(unsigned long dummy)
156 {
157 	write_lock(&clip_tbl.lock);
158 	__neigh_for_each_release(&clip_tbl, neigh_check_cb);
159 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
160 	write_unlock(&clip_tbl.lock);
161 }
162 
163 static int clip_arp_rcv(struct sk_buff *skb)
164 {
165 	struct atm_vcc *vcc;
166 
167 	pr_debug("\n");
168 	vcc = ATM_SKB(skb)->vcc;
169 	if (!vcc || !atm_charge(vcc, skb->truesize)) {
170 		dev_kfree_skb_any(skb);
171 		return 0;
172 	}
173 	pr_debug("pushing to %p\n", vcc);
174 	pr_debug("using %p\n", CLIP_VCC(vcc)->old_push);
175 	CLIP_VCC(vcc)->old_push(vcc, skb);
176 	return 0;
177 }
178 
179 static const unsigned char llc_oui[] = {
180 	0xaa,	/* DSAP: non-ISO */
181 	0xaa,	/* SSAP: non-ISO */
182 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
183 	0x00,	/* OUI: EtherType */
184 	0x00,
185 	0x00
186 };
187 
188 static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
189 {
190 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
191 
192 	pr_debug("\n");
193 
194 	if (!clip_devs) {
195 		atm_return(vcc, skb->truesize);
196 		kfree_skb(skb);
197 		return;
198 	}
199 
200 	if (!skb) {
201 		pr_debug("removing VCC %p\n", clip_vcc);
202 		if (clip_vcc->entry)
203 			unlink_clip_vcc(clip_vcc);
204 		clip_vcc->old_push(vcc, NULL);	/* pass on the bad news */
205 		kfree(clip_vcc);
206 		return;
207 	}
208 	atm_return(vcc, skb->truesize);
209 	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
210 	/* clip_vcc->entry == NULL if we don't have an IP address yet */
211 	if (!skb->dev) {
212 		dev_kfree_skb_any(skb);
213 		return;
214 	}
215 	ATM_SKB(skb)->vcc = vcc;
216 	skb_reset_mac_header(skb);
217 	if (!clip_vcc->encap ||
218 	    skb->len < RFC1483LLC_LEN ||
219 	    memcmp(skb->data, llc_oui, sizeof(llc_oui)))
220 		skb->protocol = htons(ETH_P_IP);
221 	else {
222 		skb->protocol = ((__be16 *)skb->data)[3];
223 		skb_pull(skb, RFC1483LLC_LEN);
224 		if (skb->protocol == htons(ETH_P_ARP)) {
225 			skb->dev->stats.rx_packets++;
226 			skb->dev->stats.rx_bytes += skb->len;
227 			clip_arp_rcv(skb);
228 			return;
229 		}
230 	}
231 	clip_vcc->last_use = jiffies;
232 	skb->dev->stats.rx_packets++;
233 	skb->dev->stats.rx_bytes += skb->len;
234 	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
235 	netif_rx(skb);
236 }
237 
238 /*
239  * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
240  * clip_pop is atomic with respect to the critical section in clip_start_xmit.
241  */
242 
243 static void clip_pop(struct atm_vcc *vcc, struct sk_buff *skb)
244 {
245 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
246 	struct net_device *dev = skb->dev;
247 	int old;
248 	unsigned long flags;
249 
250 	pr_debug("(vcc %p)\n", vcc);
251 	clip_vcc->old_pop(vcc, skb);
252 	/* skb->dev == NULL in outbound ARP packets */
253 	if (!dev)
254 		return;
255 	spin_lock_irqsave(&PRIV(dev)->xoff_lock, flags);
256 	if (atm_may_send(vcc, 0)) {
257 		old = xchg(&clip_vcc->xoff, 0);
258 		if (old)
259 			netif_wake_queue(dev);
260 	}
261 	spin_unlock_irqrestore(&PRIV(dev)->xoff_lock, flags);
262 }
263 
264 static void clip_neigh_solicit(struct neighbour *neigh, struct sk_buff *skb)
265 {
266 	__be32 *ip = (__be32 *) neigh->primary_key;
267 
268 	pr_debug("(neigh %p, skb %p)\n", neigh, skb);
269 	to_atmarpd(act_need, PRIV(neigh->dev)->number, *ip);
270 }
271 
272 static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
273 {
274 #ifndef CONFIG_ATM_CLIP_NO_ICMP
275 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
276 #endif
277 	kfree_skb(skb);
278 }
279 
280 static const struct neigh_ops clip_neigh_ops = {
281 	.family =		AF_INET,
282 	.solicit =		clip_neigh_solicit,
283 	.error_report =		clip_neigh_error,
284 	.output =		neigh_direct_output,
285 	.connected_output =	neigh_direct_output,
286 };
287 
288 static int clip_constructor(struct neighbour *neigh)
289 {
290 	struct atmarp_entry *entry = neighbour_priv(neigh);
291 
292 	if (neigh->tbl->family != AF_INET)
293 		return -EINVAL;
294 
295 	if (neigh->type != RTN_UNICAST)
296 		return -EINVAL;
297 
298 	neigh->nud_state = NUD_NONE;
299 	neigh->ops = &clip_neigh_ops;
300 	neigh->output = neigh->ops->output;
301 	entry->neigh = neigh;
302 	entry->vccs = NULL;
303 	entry->expires = jiffies - 1;
304 
305 	return 0;
306 }
307 
308 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
309 
310 /*
311  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
312  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
313  * don't increment the usage count. This is used to create entries in
314  * clip_setentry.
315  */
316 
317 static int clip_encap(struct atm_vcc *vcc, int mode)
318 {
319 	CLIP_VCC(vcc)->encap = mode;
320 	return 0;
321 }
322 
323 static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
324 				   struct net_device *dev)
325 {
326 	struct clip_priv *clip_priv = PRIV(dev);
327 	struct dst_entry *dst = skb_dst(skb);
328 	struct atmarp_entry *entry;
329 	struct neighbour *n;
330 	struct atm_vcc *vcc;
331 	int old;
332 	unsigned long flags;
333 
334 	pr_debug("(skb %p)\n", skb);
335 	if (!dst) {
336 		pr_err("skb_dst(skb) == NULL\n");
337 		dev_kfree_skb(skb);
338 		dev->stats.tx_dropped++;
339 		return NETDEV_TX_OK;
340 	}
341 	n = dst_get_neighbour_noref(dst);
342 	if (!n) {
343 		pr_err("NO NEIGHBOUR !\n");
344 		dev_kfree_skb(skb);
345 		dev->stats.tx_dropped++;
346 		return NETDEV_TX_OK;
347 	}
348 	entry = neighbour_priv(n);
349 	if (!entry->vccs) {
350 		if (time_after(jiffies, entry->expires)) {
351 			/* should be resolved */
352 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
353 			to_atmarpd(act_need, PRIV(dev)->number, *((__be32 *)n->primary_key));
354 		}
355 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
356 			skb_queue_tail(&entry->neigh->arp_queue, skb);
357 		else {
358 			dev_kfree_skb(skb);
359 			dev->stats.tx_dropped++;
360 		}
361 		return NETDEV_TX_OK;
362 	}
363 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
364 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
365 	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
366 	if (entry->vccs->encap) {
367 		void *here;
368 
369 		here = skb_push(skb, RFC1483LLC_LEN);
370 		memcpy(here, llc_oui, sizeof(llc_oui));
371 		((__be16 *) here)[3] = skb->protocol;
372 	}
373 	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
374 	ATM_SKB(skb)->atm_options = vcc->atm_options;
375 	entry->vccs->last_use = jiffies;
376 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
377 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
378 	if (old) {
379 		pr_warning("XOFF->XOFF transition\n");
380 		return NETDEV_TX_OK;
381 	}
382 	dev->stats.tx_packets++;
383 	dev->stats.tx_bytes += skb->len;
384 	vcc->send(vcc, skb);
385 	if (atm_may_send(vcc, 0)) {
386 		entry->vccs->xoff = 0;
387 		return NETDEV_TX_OK;
388 	}
389 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
390 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
391 	barrier();
392 	if (!entry->vccs->xoff)
393 		netif_start_queue(dev);
394 	/* Oh, we just raced with clip_pop. netif_start_queue should be
395 	   good enough, because nothing should really be asleep because
396 	   of the brief netif_stop_queue. If this isn't true or if it
397 	   changes, use netif_wake_queue instead. */
398 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
399 	return NETDEV_TX_OK;
400 }
401 
402 static int clip_mkip(struct atm_vcc *vcc, int timeout)
403 {
404 	struct clip_vcc *clip_vcc;
405 
406 	if (!vcc->push)
407 		return -EBADFD;
408 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
409 	if (!clip_vcc)
410 		return -ENOMEM;
411 	pr_debug("%p vcc %p\n", clip_vcc, vcc);
412 	clip_vcc->vcc = vcc;
413 	vcc->user_back = clip_vcc;
414 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
415 	clip_vcc->entry = NULL;
416 	clip_vcc->xoff = 0;
417 	clip_vcc->encap = 1;
418 	clip_vcc->last_use = jiffies;
419 	clip_vcc->idle_timeout = timeout * HZ;
420 	clip_vcc->old_push = vcc->push;
421 	clip_vcc->old_pop = vcc->pop;
422 	vcc->push = clip_push;
423 	vcc->pop = clip_pop;
424 
425 	/* re-process everything received between connection setup and MKIP */
426 	vcc_process_recv_queue(vcc);
427 
428 	return 0;
429 }
430 
431 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
432 {
433 	struct neighbour *neigh;
434 	struct atmarp_entry *entry;
435 	int error;
436 	struct clip_vcc *clip_vcc;
437 	struct rtable *rt;
438 
439 	if (vcc->push != clip_push) {
440 		pr_warning("non-CLIP VCC\n");
441 		return -EBADF;
442 	}
443 	clip_vcc = CLIP_VCC(vcc);
444 	if (!ip) {
445 		if (!clip_vcc->entry) {
446 			pr_err("hiding hidden ATMARP entry\n");
447 			return 0;
448 		}
449 		pr_debug("remove\n");
450 		unlink_clip_vcc(clip_vcc);
451 		return 0;
452 	}
453 	rt = ip_route_output(&init_net, ip, 0, 1, 0);
454 	if (IS_ERR(rt))
455 		return PTR_ERR(rt);
456 	neigh = __neigh_lookup(&arp_tbl, &ip, rt->dst.dev, 1);
457 	ip_rt_put(rt);
458 	if (!neigh)
459 		return -ENOMEM;
460 	entry = neighbour_priv(neigh);
461 	if (entry != clip_vcc->entry) {
462 		if (!clip_vcc->entry)
463 			pr_debug("add\n");
464 		else {
465 			pr_debug("update\n");
466 			unlink_clip_vcc(clip_vcc);
467 		}
468 		link_vcc(clip_vcc, entry);
469 	}
470 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
471 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
472 	neigh_release(neigh);
473 	return error;
474 }
475 
476 static const struct net_device_ops clip_netdev_ops = {
477 	.ndo_start_xmit		= clip_start_xmit,
478 	.ndo_neigh_construct	= clip_constructor,
479 };
480 
481 static void clip_setup(struct net_device *dev)
482 {
483 	dev->netdev_ops = &clip_netdev_ops;
484 	dev->type = ARPHRD_ATM;
485 	dev->neigh_priv_len = sizeof(struct atmarp_entry);
486 	dev->hard_header_len = RFC1483LLC_LEN;
487 	dev->mtu = RFC1626_MTU;
488 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
489 	/* When using a "real" qdisc, the qdisc determines the queue */
490 	/* length. tx_queue_len is only used for the default case, */
491 	/* without any more elaborate queuing. 100 is a reasonable */
492 	/* compromise between decent burst-tolerance and protection */
493 	/* against memory hogs. */
494 	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
495 }
496 
497 static int clip_create(int number)
498 {
499 	struct net_device *dev;
500 	struct clip_priv *clip_priv;
501 	int error;
502 
503 	if (number != -1) {
504 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
505 			if (PRIV(dev)->number == number)
506 				return -EEXIST;
507 	} else {
508 		number = 0;
509 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
510 			if (PRIV(dev)->number >= number)
511 				number = PRIV(dev)->number + 1;
512 	}
513 	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
514 	if (!dev)
515 		return -ENOMEM;
516 	clip_priv = PRIV(dev);
517 	sprintf(dev->name, "atm%d", number);
518 	spin_lock_init(&clip_priv->xoff_lock);
519 	clip_priv->number = number;
520 	error = register_netdev(dev);
521 	if (error) {
522 		free_netdev(dev);
523 		return error;
524 	}
525 	clip_priv->next = clip_devs;
526 	clip_devs = dev;
527 	pr_debug("registered (net:%s)\n", dev->name);
528 	return number;
529 }
530 
531 static int clip_device_event(struct notifier_block *this, unsigned long event,
532 			     void *arg)
533 {
534 	struct net_device *dev = arg;
535 
536 	if (!net_eq(dev_net(dev), &init_net))
537 		return NOTIFY_DONE;
538 
539 	if (event == NETDEV_UNREGISTER)
540 		return NOTIFY_DONE;
541 
542 	/* ignore non-CLIP devices */
543 	if (dev->type != ARPHRD_ATM || dev->netdev_ops != &clip_netdev_ops)
544 		return NOTIFY_DONE;
545 
546 	switch (event) {
547 	case NETDEV_UP:
548 		pr_debug("NETDEV_UP\n");
549 		to_atmarpd(act_up, PRIV(dev)->number, 0);
550 		break;
551 	case NETDEV_GOING_DOWN:
552 		pr_debug("NETDEV_DOWN\n");
553 		to_atmarpd(act_down, PRIV(dev)->number, 0);
554 		break;
555 	case NETDEV_CHANGE:
556 	case NETDEV_CHANGEMTU:
557 		pr_debug("NETDEV_CHANGE*\n");
558 		to_atmarpd(act_change, PRIV(dev)->number, 0);
559 		break;
560 	}
561 	return NOTIFY_DONE;
562 }
563 
564 static int clip_inet_event(struct notifier_block *this, unsigned long event,
565 			   void *ifa)
566 {
567 	struct in_device *in_dev;
568 
569 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
570 	/*
571 	 * Transitions are of the down-change-up type, so it's sufficient to
572 	 * handle the change on up.
573 	 */
574 	if (event != NETDEV_UP)
575 		return NOTIFY_DONE;
576 	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
577 }
578 
579 static struct notifier_block clip_dev_notifier = {
580 	.notifier_call = clip_device_event,
581 };
582 
583 
584 
585 static struct notifier_block clip_inet_notifier = {
586 	.notifier_call = clip_inet_event,
587 };
588 
589 
590 
591 static void atmarpd_close(struct atm_vcc *vcc)
592 {
593 	pr_debug("\n");
594 
595 	rtnl_lock();
596 	atmarpd = NULL;
597 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
598 	rtnl_unlock();
599 
600 	pr_debug("(done)\n");
601 	module_put(THIS_MODULE);
602 }
603 
604 static struct atmdev_ops atmarpd_dev_ops = {
605 	.close = atmarpd_close
606 };
607 
608 
609 static struct atm_dev atmarpd_dev = {
610 	.ops =			&atmarpd_dev_ops,
611 	.type =			"arpd",
612 	.number = 		999,
613 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
614 };
615 
616 
617 static int atm_init_atmarp(struct atm_vcc *vcc)
618 {
619 	rtnl_lock();
620 	if (atmarpd) {
621 		rtnl_unlock();
622 		return -EADDRINUSE;
623 	}
624 
625 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
626 
627 	atmarpd = vcc;
628 	set_bit(ATM_VF_META, &vcc->flags);
629 	set_bit(ATM_VF_READY, &vcc->flags);
630 	    /* allow replies and avoid getting closed if signaling dies */
631 	vcc->dev = &atmarpd_dev;
632 	vcc_insert_socket(sk_atm(vcc));
633 	vcc->push = NULL;
634 	vcc->pop = NULL; /* crash */
635 	vcc->push_oam = NULL; /* crash */
636 	rtnl_unlock();
637 	return 0;
638 }
639 
640 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
641 {
642 	struct atm_vcc *vcc = ATM_SD(sock);
643 	int err = 0;
644 
645 	switch (cmd) {
646 	case SIOCMKCLIP:
647 	case ATMARPD_CTRL:
648 	case ATMARP_MKIP:
649 	case ATMARP_SETENTRY:
650 	case ATMARP_ENCAP:
651 		if (!capable(CAP_NET_ADMIN))
652 			return -EPERM;
653 		break;
654 	default:
655 		return -ENOIOCTLCMD;
656 	}
657 
658 	switch (cmd) {
659 	case SIOCMKCLIP:
660 		err = clip_create(arg);
661 		break;
662 	case ATMARPD_CTRL:
663 		err = atm_init_atmarp(vcc);
664 		if (!err) {
665 			sock->state = SS_CONNECTED;
666 			__module_get(THIS_MODULE);
667 		}
668 		break;
669 	case ATMARP_MKIP:
670 		err = clip_mkip(vcc, arg);
671 		break;
672 	case ATMARP_SETENTRY:
673 		err = clip_setentry(vcc, (__force __be32)arg);
674 		break;
675 	case ATMARP_ENCAP:
676 		err = clip_encap(vcc, arg);
677 		break;
678 	}
679 	return err;
680 }
681 
682 static struct atm_ioctl clip_ioctl_ops = {
683 	.owner = THIS_MODULE,
684 	.ioctl = clip_ioctl,
685 };
686 
687 #ifdef CONFIG_PROC_FS
688 
689 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
690 {
691 	static int code[] = { 1, 2, 10, 6, 1, 0 };
692 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
693 
694 	if (*addr->sas_addr.pub) {
695 		seq_printf(seq, "%s", addr->sas_addr.pub);
696 		if (*addr->sas_addr.prv)
697 			seq_putc(seq, '+');
698 	} else if (!*addr->sas_addr.prv) {
699 		seq_printf(seq, "%s", "(none)");
700 		return;
701 	}
702 	if (*addr->sas_addr.prv) {
703 		unsigned char *prv = addr->sas_addr.prv;
704 		int *fields;
705 		int i, j;
706 
707 		fields = *prv == ATM_AFI_E164 ? e164 : code;
708 		for (i = 0; fields[i]; i++) {
709 			for (j = fields[i]; j; j--)
710 				seq_printf(seq, "%02X", *prv++);
711 			if (fields[i + 1])
712 				seq_putc(seq, '.');
713 		}
714 	}
715 }
716 
717 /* This means the neighbour entry has no attached VCC objects. */
718 #define SEQ_NO_VCC_TOKEN	((void *) 2)
719 
720 static void atmarp_info(struct seq_file *seq, struct neighbour *n,
721 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
722 {
723 	struct net_device *dev = n->dev;
724 	unsigned long exp;
725 	char buf[17];
726 	int svc, llc, off;
727 
728 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
729 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
730 
731 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
732 
733 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
734 		exp = entry->neigh->used;
735 	else
736 		exp = clip_vcc->last_use;
737 
738 	exp = (jiffies - exp) / HZ;
739 
740 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
741 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
742 
743 	off = scnprintf(buf, sizeof(buf) - 1, "%pI4", n->primary_key);
744 	while (off < 16)
745 		buf[off++] = ' ';
746 	buf[off] = '\0';
747 	seq_printf(seq, "%s", buf);
748 
749 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
750 		if (time_before(jiffies, entry->expires))
751 			seq_printf(seq, "(resolving)\n");
752 		else
753 			seq_printf(seq, "(expired, ref %d)\n",
754 				   atomic_read(&entry->neigh->refcnt));
755 	} else if (!svc) {
756 		seq_printf(seq, "%d.%d.%d\n",
757 			   clip_vcc->vcc->dev->number,
758 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
759 	} else {
760 		svc_addr(seq, &clip_vcc->vcc->remote);
761 		seq_putc(seq, '\n');
762 	}
763 }
764 
765 struct clip_seq_state {
766 	/* This member must be first. */
767 	struct neigh_seq_state ns;
768 
769 	/* Local to clip specific iteration. */
770 	struct clip_vcc *vcc;
771 };
772 
773 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
774 					  struct clip_vcc *curr)
775 {
776 	if (!curr) {
777 		curr = e->vccs;
778 		if (!curr)
779 			return SEQ_NO_VCC_TOKEN;
780 		return curr;
781 	}
782 	if (curr == SEQ_NO_VCC_TOKEN)
783 		return NULL;
784 
785 	curr = curr->next;
786 
787 	return curr;
788 }
789 
790 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
791 			       struct atmarp_entry *e, loff_t * pos)
792 {
793 	struct clip_vcc *vcc = state->vcc;
794 
795 	vcc = clip_seq_next_vcc(e, vcc);
796 	if (vcc && pos != NULL) {
797 		while (*pos) {
798 			vcc = clip_seq_next_vcc(e, vcc);
799 			if (!vcc)
800 				break;
801 			--(*pos);
802 		}
803 	}
804 	state->vcc = vcc;
805 
806 	return vcc;
807 }
808 
809 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
810 			       struct neighbour *n, loff_t * pos)
811 {
812 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
813 
814 	if (n->dev->type != ARPHRD_ATM)
815 		return NULL;
816 
817 	return clip_seq_vcc_walk(state, neighbour_priv(n), pos);
818 }
819 
820 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
821 {
822 	struct clip_seq_state *state = seq->private;
823 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
824 	return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_NEIGH_ONLY);
825 }
826 
827 static int clip_seq_show(struct seq_file *seq, void *v)
828 {
829 	static char atm_arp_banner[] =
830 	    "IPitf TypeEncp Idle IP address      ATM address\n";
831 
832 	if (v == SEQ_START_TOKEN) {
833 		seq_puts(seq, atm_arp_banner);
834 	} else {
835 		struct clip_seq_state *state = seq->private;
836 		struct clip_vcc *vcc = state->vcc;
837 		struct neighbour *n = v;
838 
839 		atmarp_info(seq, n, neighbour_priv(n), vcc);
840 	}
841 	return 0;
842 }
843 
844 static const struct seq_operations arp_seq_ops = {
845 	.start	= clip_seq_start,
846 	.next	= neigh_seq_next,
847 	.stop	= neigh_seq_stop,
848 	.show	= clip_seq_show,
849 };
850 
851 static int arp_seq_open(struct inode *inode, struct file *file)
852 {
853 	return seq_open_net(inode, file, &arp_seq_ops,
854 			    sizeof(struct clip_seq_state));
855 }
856 
857 static const struct file_operations arp_seq_fops = {
858 	.open		= arp_seq_open,
859 	.read		= seq_read,
860 	.llseek		= seq_lseek,
861 	.release	= seq_release_net,
862 	.owner		= THIS_MODULE
863 };
864 #endif
865 
866 static void atm_clip_exit_noproc(void);
867 
868 static int __init atm_clip_init(void)
869 {
870 	register_atm_ioctl(&clip_ioctl_ops);
871 	register_netdevice_notifier(&clip_dev_notifier);
872 	register_inetaddr_notifier(&clip_inet_notifier);
873 
874 	setup_timer(&idle_timer, idle_timer_check, 0);
875 
876 #ifdef CONFIG_PROC_FS
877 	{
878 		struct proc_dir_entry *p;
879 
880 		p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
881 		if (!p) {
882 			pr_err("Unable to initialize /proc/net/atm/arp\n");
883 			atm_clip_exit_noproc();
884 			return -ENOMEM;
885 		}
886 	}
887 #endif
888 
889 	return 0;
890 }
891 
892 static void atm_clip_exit_noproc(void)
893 {
894 	struct net_device *dev, *next;
895 
896 	unregister_inetaddr_notifier(&clip_inet_notifier);
897 	unregister_netdevice_notifier(&clip_dev_notifier);
898 
899 	deregister_atm_ioctl(&clip_ioctl_ops);
900 
901 	/* First, stop the idle timer, so it stops banging
902 	 * on the table.
903 	 */
904 	del_timer_sync(&idle_timer);
905 
906 	dev = clip_devs;
907 	while (dev) {
908 		next = PRIV(dev)->next;
909 		unregister_netdev(dev);
910 		free_netdev(dev);
911 		dev = next;
912 	}
913 }
914 
915 static void __exit atm_clip_exit(void)
916 {
917 	remove_proc_entry("arp", atm_proc_root);
918 
919 	atm_clip_exit_noproc();
920 }
921 
922 module_init(atm_clip_init);
923 module_exit(atm_clip_exit);
924 MODULE_AUTHOR("Werner Almesberger");
925 MODULE_DESCRIPTION("Classical/IP over ATM interface");
926 MODULE_LICENSE("GPL");
927