xref: /linux/net/atm/clip.c (revision 800c5eb7b5eba6cb2a32738d763fd59f0fbcdde4)
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 	struct rtable *rt;
332 	__be32 *daddr;
333 	int old;
334 	unsigned long flags;
335 
336 	pr_debug("(skb %p)\n", skb);
337 	if (!dst) {
338 		pr_err("skb_dst(skb) == NULL\n");
339 		dev_kfree_skb(skb);
340 		dev->stats.tx_dropped++;
341 		return NETDEV_TX_OK;
342 	}
343 	rt = (struct rtable *) dst;
344 	if (rt->rt_gateway)
345 		daddr = &rt->rt_gateway;
346 	else
347 		daddr = &ip_hdr(skb)->daddr;
348 	n = dst_neigh_lookup(dst, daddr);
349 	if (!n) {
350 		pr_err("NO NEIGHBOUR !\n");
351 		dev_kfree_skb(skb);
352 		dev->stats.tx_dropped++;
353 		return NETDEV_TX_OK;
354 	}
355 	entry = neighbour_priv(n);
356 	if (!entry->vccs) {
357 		if (time_after(jiffies, entry->expires)) {
358 			/* should be resolved */
359 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
360 			to_atmarpd(act_need, PRIV(dev)->number, *((__be32 *)n->primary_key));
361 		}
362 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
363 			skb_queue_tail(&entry->neigh->arp_queue, skb);
364 		else {
365 			dev_kfree_skb(skb);
366 			dev->stats.tx_dropped++;
367 		}
368 		goto out_release_neigh;
369 	}
370 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
371 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
372 	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
373 	if (entry->vccs->encap) {
374 		void *here;
375 
376 		here = skb_push(skb, RFC1483LLC_LEN);
377 		memcpy(here, llc_oui, sizeof(llc_oui));
378 		((__be16 *) here)[3] = skb->protocol;
379 	}
380 	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
381 	ATM_SKB(skb)->atm_options = vcc->atm_options;
382 	entry->vccs->last_use = jiffies;
383 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
384 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
385 	if (old) {
386 		pr_warning("XOFF->XOFF transition\n");
387 		goto out_release_neigh;
388 	}
389 	dev->stats.tx_packets++;
390 	dev->stats.tx_bytes += skb->len;
391 	vcc->send(vcc, skb);
392 	if (atm_may_send(vcc, 0)) {
393 		entry->vccs->xoff = 0;
394 		goto out_release_neigh;
395 	}
396 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
397 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
398 	barrier();
399 	if (!entry->vccs->xoff)
400 		netif_start_queue(dev);
401 	/* Oh, we just raced with clip_pop. netif_start_queue should be
402 	   good enough, because nothing should really be asleep because
403 	   of the brief netif_stop_queue. If this isn't true or if it
404 	   changes, use netif_wake_queue instead. */
405 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
406 out_release_neigh:
407 	neigh_release(n);
408 	return NETDEV_TX_OK;
409 }
410 
411 static int clip_mkip(struct atm_vcc *vcc, int timeout)
412 {
413 	struct clip_vcc *clip_vcc;
414 
415 	if (!vcc->push)
416 		return -EBADFD;
417 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
418 	if (!clip_vcc)
419 		return -ENOMEM;
420 	pr_debug("%p vcc %p\n", clip_vcc, vcc);
421 	clip_vcc->vcc = vcc;
422 	vcc->user_back = clip_vcc;
423 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
424 	clip_vcc->entry = NULL;
425 	clip_vcc->xoff = 0;
426 	clip_vcc->encap = 1;
427 	clip_vcc->last_use = jiffies;
428 	clip_vcc->idle_timeout = timeout * HZ;
429 	clip_vcc->old_push = vcc->push;
430 	clip_vcc->old_pop = vcc->pop;
431 	vcc->push = clip_push;
432 	vcc->pop = clip_pop;
433 
434 	/* re-process everything received between connection setup and MKIP */
435 	vcc_process_recv_queue(vcc);
436 
437 	return 0;
438 }
439 
440 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
441 {
442 	struct neighbour *neigh;
443 	struct atmarp_entry *entry;
444 	int error;
445 	struct clip_vcc *clip_vcc;
446 	struct rtable *rt;
447 
448 	if (vcc->push != clip_push) {
449 		pr_warning("non-CLIP VCC\n");
450 		return -EBADF;
451 	}
452 	clip_vcc = CLIP_VCC(vcc);
453 	if (!ip) {
454 		if (!clip_vcc->entry) {
455 			pr_err("hiding hidden ATMARP entry\n");
456 			return 0;
457 		}
458 		pr_debug("remove\n");
459 		unlink_clip_vcc(clip_vcc);
460 		return 0;
461 	}
462 	rt = ip_route_output(&init_net, ip, 0, 1, 0);
463 	if (IS_ERR(rt))
464 		return PTR_ERR(rt);
465 	neigh = __neigh_lookup(&arp_tbl, &ip, rt->dst.dev, 1);
466 	ip_rt_put(rt);
467 	if (!neigh)
468 		return -ENOMEM;
469 	entry = neighbour_priv(neigh);
470 	if (entry != clip_vcc->entry) {
471 		if (!clip_vcc->entry)
472 			pr_debug("add\n");
473 		else {
474 			pr_debug("update\n");
475 			unlink_clip_vcc(clip_vcc);
476 		}
477 		link_vcc(clip_vcc, entry);
478 	}
479 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
480 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
481 	neigh_release(neigh);
482 	return error;
483 }
484 
485 static const struct net_device_ops clip_netdev_ops = {
486 	.ndo_start_xmit		= clip_start_xmit,
487 	.ndo_neigh_construct	= clip_constructor,
488 };
489 
490 static void clip_setup(struct net_device *dev)
491 {
492 	dev->netdev_ops = &clip_netdev_ops;
493 	dev->type = ARPHRD_ATM;
494 	dev->neigh_priv_len = sizeof(struct atmarp_entry);
495 	dev->hard_header_len = RFC1483LLC_LEN;
496 	dev->mtu = RFC1626_MTU;
497 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
498 	/* When using a "real" qdisc, the qdisc determines the queue */
499 	/* length. tx_queue_len is only used for the default case, */
500 	/* without any more elaborate queuing. 100 is a reasonable */
501 	/* compromise between decent burst-tolerance and protection */
502 	/* against memory hogs. */
503 	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
504 }
505 
506 static int clip_create(int number)
507 {
508 	struct net_device *dev;
509 	struct clip_priv *clip_priv;
510 	int error;
511 
512 	if (number != -1) {
513 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
514 			if (PRIV(dev)->number == number)
515 				return -EEXIST;
516 	} else {
517 		number = 0;
518 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
519 			if (PRIV(dev)->number >= number)
520 				number = PRIV(dev)->number + 1;
521 	}
522 	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
523 	if (!dev)
524 		return -ENOMEM;
525 	clip_priv = PRIV(dev);
526 	sprintf(dev->name, "atm%d", number);
527 	spin_lock_init(&clip_priv->xoff_lock);
528 	clip_priv->number = number;
529 	error = register_netdev(dev);
530 	if (error) {
531 		free_netdev(dev);
532 		return error;
533 	}
534 	clip_priv->next = clip_devs;
535 	clip_devs = dev;
536 	pr_debug("registered (net:%s)\n", dev->name);
537 	return number;
538 }
539 
540 static int clip_device_event(struct notifier_block *this, unsigned long event,
541 			     void *arg)
542 {
543 	struct net_device *dev = arg;
544 
545 	if (!net_eq(dev_net(dev), &init_net))
546 		return NOTIFY_DONE;
547 
548 	if (event == NETDEV_UNREGISTER)
549 		return NOTIFY_DONE;
550 
551 	/* ignore non-CLIP devices */
552 	if (dev->type != ARPHRD_ATM || dev->netdev_ops != &clip_netdev_ops)
553 		return NOTIFY_DONE;
554 
555 	switch (event) {
556 	case NETDEV_UP:
557 		pr_debug("NETDEV_UP\n");
558 		to_atmarpd(act_up, PRIV(dev)->number, 0);
559 		break;
560 	case NETDEV_GOING_DOWN:
561 		pr_debug("NETDEV_DOWN\n");
562 		to_atmarpd(act_down, PRIV(dev)->number, 0);
563 		break;
564 	case NETDEV_CHANGE:
565 	case NETDEV_CHANGEMTU:
566 		pr_debug("NETDEV_CHANGE*\n");
567 		to_atmarpd(act_change, PRIV(dev)->number, 0);
568 		break;
569 	}
570 	return NOTIFY_DONE;
571 }
572 
573 static int clip_inet_event(struct notifier_block *this, unsigned long event,
574 			   void *ifa)
575 {
576 	struct in_device *in_dev;
577 
578 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
579 	/*
580 	 * Transitions are of the down-change-up type, so it's sufficient to
581 	 * handle the change on up.
582 	 */
583 	if (event != NETDEV_UP)
584 		return NOTIFY_DONE;
585 	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
586 }
587 
588 static struct notifier_block clip_dev_notifier = {
589 	.notifier_call = clip_device_event,
590 };
591 
592 
593 
594 static struct notifier_block clip_inet_notifier = {
595 	.notifier_call = clip_inet_event,
596 };
597 
598 
599 
600 static void atmarpd_close(struct atm_vcc *vcc)
601 {
602 	pr_debug("\n");
603 
604 	rtnl_lock();
605 	atmarpd = NULL;
606 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
607 	rtnl_unlock();
608 
609 	pr_debug("(done)\n");
610 	module_put(THIS_MODULE);
611 }
612 
613 static struct atmdev_ops atmarpd_dev_ops = {
614 	.close = atmarpd_close
615 };
616 
617 
618 static struct atm_dev atmarpd_dev = {
619 	.ops =			&atmarpd_dev_ops,
620 	.type =			"arpd",
621 	.number = 		999,
622 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
623 };
624 
625 
626 static int atm_init_atmarp(struct atm_vcc *vcc)
627 {
628 	rtnl_lock();
629 	if (atmarpd) {
630 		rtnl_unlock();
631 		return -EADDRINUSE;
632 	}
633 
634 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
635 
636 	atmarpd = vcc;
637 	set_bit(ATM_VF_META, &vcc->flags);
638 	set_bit(ATM_VF_READY, &vcc->flags);
639 	    /* allow replies and avoid getting closed if signaling dies */
640 	vcc->dev = &atmarpd_dev;
641 	vcc_insert_socket(sk_atm(vcc));
642 	vcc->push = NULL;
643 	vcc->pop = NULL; /* crash */
644 	vcc->push_oam = NULL; /* crash */
645 	rtnl_unlock();
646 	return 0;
647 }
648 
649 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
650 {
651 	struct atm_vcc *vcc = ATM_SD(sock);
652 	int err = 0;
653 
654 	switch (cmd) {
655 	case SIOCMKCLIP:
656 	case ATMARPD_CTRL:
657 	case ATMARP_MKIP:
658 	case ATMARP_SETENTRY:
659 	case ATMARP_ENCAP:
660 		if (!capable(CAP_NET_ADMIN))
661 			return -EPERM;
662 		break;
663 	default:
664 		return -ENOIOCTLCMD;
665 	}
666 
667 	switch (cmd) {
668 	case SIOCMKCLIP:
669 		err = clip_create(arg);
670 		break;
671 	case ATMARPD_CTRL:
672 		err = atm_init_atmarp(vcc);
673 		if (!err) {
674 			sock->state = SS_CONNECTED;
675 			__module_get(THIS_MODULE);
676 		}
677 		break;
678 	case ATMARP_MKIP:
679 		err = clip_mkip(vcc, arg);
680 		break;
681 	case ATMARP_SETENTRY:
682 		err = clip_setentry(vcc, (__force __be32)arg);
683 		break;
684 	case ATMARP_ENCAP:
685 		err = clip_encap(vcc, arg);
686 		break;
687 	}
688 	return err;
689 }
690 
691 static struct atm_ioctl clip_ioctl_ops = {
692 	.owner = THIS_MODULE,
693 	.ioctl = clip_ioctl,
694 };
695 
696 #ifdef CONFIG_PROC_FS
697 
698 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
699 {
700 	static int code[] = { 1, 2, 10, 6, 1, 0 };
701 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
702 
703 	if (*addr->sas_addr.pub) {
704 		seq_printf(seq, "%s", addr->sas_addr.pub);
705 		if (*addr->sas_addr.prv)
706 			seq_putc(seq, '+');
707 	} else if (!*addr->sas_addr.prv) {
708 		seq_printf(seq, "%s", "(none)");
709 		return;
710 	}
711 	if (*addr->sas_addr.prv) {
712 		unsigned char *prv = addr->sas_addr.prv;
713 		int *fields;
714 		int i, j;
715 
716 		fields = *prv == ATM_AFI_E164 ? e164 : code;
717 		for (i = 0; fields[i]; i++) {
718 			for (j = fields[i]; j; j--)
719 				seq_printf(seq, "%02X", *prv++);
720 			if (fields[i + 1])
721 				seq_putc(seq, '.');
722 		}
723 	}
724 }
725 
726 /* This means the neighbour entry has no attached VCC objects. */
727 #define SEQ_NO_VCC_TOKEN	((void *) 2)
728 
729 static void atmarp_info(struct seq_file *seq, struct neighbour *n,
730 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
731 {
732 	struct net_device *dev = n->dev;
733 	unsigned long exp;
734 	char buf[17];
735 	int svc, llc, off;
736 
737 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
738 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
739 
740 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
741 
742 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
743 		exp = entry->neigh->used;
744 	else
745 		exp = clip_vcc->last_use;
746 
747 	exp = (jiffies - exp) / HZ;
748 
749 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
750 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
751 
752 	off = scnprintf(buf, sizeof(buf) - 1, "%pI4", n->primary_key);
753 	while (off < 16)
754 		buf[off++] = ' ';
755 	buf[off] = '\0';
756 	seq_printf(seq, "%s", buf);
757 
758 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
759 		if (time_before(jiffies, entry->expires))
760 			seq_printf(seq, "(resolving)\n");
761 		else
762 			seq_printf(seq, "(expired, ref %d)\n",
763 				   atomic_read(&entry->neigh->refcnt));
764 	} else if (!svc) {
765 		seq_printf(seq, "%d.%d.%d\n",
766 			   clip_vcc->vcc->dev->number,
767 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
768 	} else {
769 		svc_addr(seq, &clip_vcc->vcc->remote);
770 		seq_putc(seq, '\n');
771 	}
772 }
773 
774 struct clip_seq_state {
775 	/* This member must be first. */
776 	struct neigh_seq_state ns;
777 
778 	/* Local to clip specific iteration. */
779 	struct clip_vcc *vcc;
780 };
781 
782 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
783 					  struct clip_vcc *curr)
784 {
785 	if (!curr) {
786 		curr = e->vccs;
787 		if (!curr)
788 			return SEQ_NO_VCC_TOKEN;
789 		return curr;
790 	}
791 	if (curr == SEQ_NO_VCC_TOKEN)
792 		return NULL;
793 
794 	curr = curr->next;
795 
796 	return curr;
797 }
798 
799 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
800 			       struct atmarp_entry *e, loff_t * pos)
801 {
802 	struct clip_vcc *vcc = state->vcc;
803 
804 	vcc = clip_seq_next_vcc(e, vcc);
805 	if (vcc && pos != NULL) {
806 		while (*pos) {
807 			vcc = clip_seq_next_vcc(e, vcc);
808 			if (!vcc)
809 				break;
810 			--(*pos);
811 		}
812 	}
813 	state->vcc = vcc;
814 
815 	return vcc;
816 }
817 
818 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
819 			       struct neighbour *n, loff_t * pos)
820 {
821 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
822 
823 	if (n->dev->type != ARPHRD_ATM)
824 		return NULL;
825 
826 	return clip_seq_vcc_walk(state, neighbour_priv(n), pos);
827 }
828 
829 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
830 {
831 	struct clip_seq_state *state = seq->private;
832 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
833 	return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_NEIGH_ONLY);
834 }
835 
836 static int clip_seq_show(struct seq_file *seq, void *v)
837 {
838 	static char atm_arp_banner[] =
839 	    "IPitf TypeEncp Idle IP address      ATM address\n";
840 
841 	if (v == SEQ_START_TOKEN) {
842 		seq_puts(seq, atm_arp_banner);
843 	} else {
844 		struct clip_seq_state *state = seq->private;
845 		struct clip_vcc *vcc = state->vcc;
846 		struct neighbour *n = v;
847 
848 		atmarp_info(seq, n, neighbour_priv(n), vcc);
849 	}
850 	return 0;
851 }
852 
853 static const struct seq_operations arp_seq_ops = {
854 	.start	= clip_seq_start,
855 	.next	= neigh_seq_next,
856 	.stop	= neigh_seq_stop,
857 	.show	= clip_seq_show,
858 };
859 
860 static int arp_seq_open(struct inode *inode, struct file *file)
861 {
862 	return seq_open_net(inode, file, &arp_seq_ops,
863 			    sizeof(struct clip_seq_state));
864 }
865 
866 static const struct file_operations arp_seq_fops = {
867 	.open		= arp_seq_open,
868 	.read		= seq_read,
869 	.llseek		= seq_lseek,
870 	.release	= seq_release_net,
871 	.owner		= THIS_MODULE
872 };
873 #endif
874 
875 static void atm_clip_exit_noproc(void);
876 
877 static int __init atm_clip_init(void)
878 {
879 	register_atm_ioctl(&clip_ioctl_ops);
880 	register_netdevice_notifier(&clip_dev_notifier);
881 	register_inetaddr_notifier(&clip_inet_notifier);
882 
883 	setup_timer(&idle_timer, idle_timer_check, 0);
884 
885 #ifdef CONFIG_PROC_FS
886 	{
887 		struct proc_dir_entry *p;
888 
889 		p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
890 		if (!p) {
891 			pr_err("Unable to initialize /proc/net/atm/arp\n");
892 			atm_clip_exit_noproc();
893 			return -ENOMEM;
894 		}
895 	}
896 #endif
897 
898 	return 0;
899 }
900 
901 static void atm_clip_exit_noproc(void)
902 {
903 	struct net_device *dev, *next;
904 
905 	unregister_inetaddr_notifier(&clip_inet_notifier);
906 	unregister_netdevice_notifier(&clip_dev_notifier);
907 
908 	deregister_atm_ioctl(&clip_ioctl_ops);
909 
910 	/* First, stop the idle timer, so it stops banging
911 	 * on the table.
912 	 */
913 	del_timer_sync(&idle_timer);
914 
915 	dev = clip_devs;
916 	while (dev) {
917 		next = PRIV(dev)->next;
918 		unregister_netdev(dev);
919 		free_netdev(dev);
920 		dev = next;
921 	}
922 }
923 
924 static void __exit atm_clip_exit(void)
925 {
926 	remove_proc_entry("arp", atm_proc_root);
927 
928 	atm_clip_exit_noproc();
929 }
930 
931 module_init(atm_clip_init);
932 module_exit(atm_clip_exit);
933 MODULE_AUTHOR("Werner Almesberger");
934 MODULE_DESCRIPTION("Classical/IP over ATM interface");
935 MODULE_LICENSE("GPL");
936