xref: /openbmc/linux/net/atm/clip.c (revision 615c36f5)
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 <linux/param.h> /* for HZ */
37 #include <linux/uaccess.h>
38 #include <asm/byteorder.h> /* for htons etc. */
39 #include <asm/system.h> /* save/restore_flags */
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 neigh_table clip_tbl;
49 static struct timer_list idle_timer;
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 = (struct atmarp_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, skb->len);
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);
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 = NEIGH2ENTRY(n);
123 	struct clip_vcc *cv;
124 
125 	for (cv = entry->vccs; cv; cv = cv->next) {
126 		unsigned long exp = cv->last_use + cv->idle_timeout;
127 
128 		if (cv->idle_timeout && time_after(jiffies, exp)) {
129 			pr_debug("releasing vcc %p->%p of entry %p\n",
130 				 cv, cv->vcc, entry);
131 			vcc_release_async(cv->vcc, -ETIMEDOUT);
132 		}
133 	}
134 
135 	if (entry->vccs || time_before(jiffies, entry->expires))
136 		return 0;
137 
138 	if (atomic_read(&n->refcnt) > 1) {
139 		struct sk_buff *skb;
140 
141 		pr_debug("destruction postponed with ref %d\n",
142 			 atomic_read(&n->refcnt));
143 
144 		while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
145 			dev_kfree_skb(skb);
146 
147 		return 0;
148 	}
149 
150 	pr_debug("expired neigh %p\n", n);
151 	return 1;
152 }
153 
154 static void idle_timer_check(unsigned long dummy)
155 {
156 	write_lock(&clip_tbl.lock);
157 	__neigh_for_each_release(&clip_tbl, neigh_check_cb);
158 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
159 	write_unlock(&clip_tbl.lock);
160 }
161 
162 static int clip_arp_rcv(struct sk_buff *skb)
163 {
164 	struct atm_vcc *vcc;
165 
166 	pr_debug("\n");
167 	vcc = ATM_SKB(skb)->vcc;
168 	if (!vcc || !atm_charge(vcc, skb->truesize)) {
169 		dev_kfree_skb_any(skb);
170 		return 0;
171 	}
172 	pr_debug("pushing to %p\n", vcc);
173 	pr_debug("using %p\n", CLIP_VCC(vcc)->old_push);
174 	CLIP_VCC(vcc)->old_push(vcc, skb);
175 	return 0;
176 }
177 
178 static const unsigned char llc_oui[] = {
179 	0xaa,	/* DSAP: non-ISO */
180 	0xaa,	/* SSAP: non-ISO */
181 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
182 	0x00,	/* OUI: EtherType */
183 	0x00,
184 	0x00
185 };
186 
187 static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
188 {
189 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
190 
191 	pr_debug("\n");
192 	if (!skb) {
193 		pr_debug("removing VCC %p\n", clip_vcc);
194 		if (clip_vcc->entry)
195 			unlink_clip_vcc(clip_vcc);
196 		clip_vcc->old_push(vcc, NULL);	/* pass on the bad news */
197 		kfree(clip_vcc);
198 		return;
199 	}
200 	atm_return(vcc, skb->truesize);
201 	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
202 	/* clip_vcc->entry == NULL if we don't have an IP address yet */
203 	if (!skb->dev) {
204 		dev_kfree_skb_any(skb);
205 		return;
206 	}
207 	ATM_SKB(skb)->vcc = vcc;
208 	skb_reset_mac_header(skb);
209 	if (!clip_vcc->encap ||
210 	    skb->len < RFC1483LLC_LEN ||
211 	    memcmp(skb->data, llc_oui, sizeof(llc_oui)))
212 		skb->protocol = htons(ETH_P_IP);
213 	else {
214 		skb->protocol = ((__be16 *)skb->data)[3];
215 		skb_pull(skb, RFC1483LLC_LEN);
216 		if (skb->protocol == htons(ETH_P_ARP)) {
217 			skb->dev->stats.rx_packets++;
218 			skb->dev->stats.rx_bytes += skb->len;
219 			clip_arp_rcv(skb);
220 			return;
221 		}
222 	}
223 	clip_vcc->last_use = jiffies;
224 	skb->dev->stats.rx_packets++;
225 	skb->dev->stats.rx_bytes += skb->len;
226 	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
227 	netif_rx(skb);
228 }
229 
230 /*
231  * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
232  * clip_pop is atomic with respect to the critical section in clip_start_xmit.
233  */
234 
235 static void clip_pop(struct atm_vcc *vcc, struct sk_buff *skb)
236 {
237 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
238 	struct net_device *dev = skb->dev;
239 	int old;
240 	unsigned long flags;
241 
242 	pr_debug("(vcc %p)\n", vcc);
243 	clip_vcc->old_pop(vcc, skb);
244 	/* skb->dev == NULL in outbound ARP packets */
245 	if (!dev)
246 		return;
247 	spin_lock_irqsave(&PRIV(dev)->xoff_lock, flags);
248 	if (atm_may_send(vcc, 0)) {
249 		old = xchg(&clip_vcc->xoff, 0);
250 		if (old)
251 			netif_wake_queue(dev);
252 	}
253 	spin_unlock_irqrestore(&PRIV(dev)->xoff_lock, flags);
254 }
255 
256 static void clip_neigh_solicit(struct neighbour *neigh, struct sk_buff *skb)
257 {
258 	pr_debug("(neigh %p, skb %p)\n", neigh, skb);
259 	to_atmarpd(act_need, PRIV(neigh->dev)->number, NEIGH2ENTRY(neigh)->ip);
260 }
261 
262 static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
263 {
264 #ifndef CONFIG_ATM_CLIP_NO_ICMP
265 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
266 #endif
267 	kfree_skb(skb);
268 }
269 
270 static const struct neigh_ops clip_neigh_ops = {
271 	.family =		AF_INET,
272 	.solicit =		clip_neigh_solicit,
273 	.error_report =		clip_neigh_error,
274 	.output =		neigh_direct_output,
275 	.connected_output =	neigh_direct_output,
276 };
277 
278 static int clip_constructor(struct neighbour *neigh)
279 {
280 	struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
281 	struct net_device *dev = neigh->dev;
282 	struct in_device *in_dev;
283 	struct neigh_parms *parms;
284 
285 	pr_debug("(neigh %p, entry %p)\n", neigh, entry);
286 	neigh->type = inet_addr_type(&init_net, entry->ip);
287 	if (neigh->type != RTN_UNICAST)
288 		return -EINVAL;
289 
290 	rcu_read_lock();
291 	in_dev = __in_dev_get_rcu(dev);
292 	if (!in_dev) {
293 		rcu_read_unlock();
294 		return -EINVAL;
295 	}
296 
297 	parms = in_dev->arp_parms;
298 	__neigh_parms_put(neigh->parms);
299 	neigh->parms = neigh_parms_clone(parms);
300 	rcu_read_unlock();
301 
302 	neigh->ops = &clip_neigh_ops;
303 	neigh->output = neigh->nud_state & NUD_VALID ?
304 	    neigh->ops->connected_output : neigh->ops->output;
305 	entry->neigh = neigh;
306 	entry->vccs = NULL;
307 	entry->expires = jiffies - 1;
308 	return 0;
309 }
310 
311 static u32 clip_hash(const void *pkey, const struct net_device *dev, __u32 rnd)
312 {
313 	return jhash_2words(*(u32 *) pkey, dev->ifindex, rnd);
314 }
315 
316 static struct neigh_table clip_tbl = {
317 	.family 	= AF_INET,
318 	.entry_size 	= sizeof(struct neighbour)+sizeof(struct atmarp_entry),
319 	.key_len 	= 4,
320 	.hash 		= clip_hash,
321 	.constructor 	= clip_constructor,
322 	.id 		= "clip_arp_cache",
323 
324 	/* parameters are copied from ARP ... */
325 	.parms = {
326 		.tbl 			= &clip_tbl,
327 		.base_reachable_time 	= 30 * HZ,
328 		.retrans_time 		= 1 * HZ,
329 		.gc_staletime 		= 60 * HZ,
330 		.reachable_time 	= 30 * HZ,
331 		.delay_probe_time 	= 5 * HZ,
332 		.queue_len 		= 3,
333 		.ucast_probes 		= 3,
334 		.mcast_probes 		= 3,
335 		.anycast_delay 		= 1 * HZ,
336 		.proxy_delay 		= (8 * HZ) / 10,
337 		.proxy_qlen 		= 64,
338 		.locktime 		= 1 * HZ,
339 	},
340 	.gc_interval 	= 30 * HZ,
341 	.gc_thresh1 	= 128,
342 	.gc_thresh2 	= 512,
343 	.gc_thresh3 	= 1024,
344 };
345 
346 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
347 
348 /*
349  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
350  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
351  * don't increment the usage count. This is used to create entries in
352  * clip_setentry.
353  */
354 
355 static int clip_encap(struct atm_vcc *vcc, int mode)
356 {
357 	CLIP_VCC(vcc)->encap = mode;
358 	return 0;
359 }
360 
361 static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
362 				   struct net_device *dev)
363 {
364 	struct clip_priv *clip_priv = PRIV(dev);
365 	struct dst_entry *dst = skb_dst(skb);
366 	struct atmarp_entry *entry;
367 	struct neighbour *n;
368 	struct atm_vcc *vcc;
369 	int old;
370 	unsigned long flags;
371 
372 	pr_debug("(skb %p)\n", skb);
373 	if (!dst) {
374 		pr_err("skb_dst(skb) == NULL\n");
375 		dev_kfree_skb(skb);
376 		dev->stats.tx_dropped++;
377 		return NETDEV_TX_OK;
378 	}
379 	n = dst_get_neighbour(dst);
380 	if (!n) {
381 #if 0
382 		n = clip_find_neighbour(skb_dst(skb), 1);
383 		if (!n) {
384 			dev_kfree_skb(skb);	/* lost that one */
385 			dev->stats.tx_dropped++;
386 			return 0;
387 		}
388 		dst_set_neighbour(dst, n);
389 #endif
390 		pr_err("NO NEIGHBOUR !\n");
391 		dev_kfree_skb(skb);
392 		dev->stats.tx_dropped++;
393 		return NETDEV_TX_OK;
394 	}
395 	entry = NEIGH2ENTRY(n);
396 	if (!entry->vccs) {
397 		if (time_after(jiffies, entry->expires)) {
398 			/* should be resolved */
399 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
400 			to_atmarpd(act_need, PRIV(dev)->number, entry->ip);
401 		}
402 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
403 			skb_queue_tail(&entry->neigh->arp_queue, skb);
404 		else {
405 			dev_kfree_skb(skb);
406 			dev->stats.tx_dropped++;
407 		}
408 		return NETDEV_TX_OK;
409 	}
410 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
411 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
412 	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
413 	if (entry->vccs->encap) {
414 		void *here;
415 
416 		here = skb_push(skb, RFC1483LLC_LEN);
417 		memcpy(here, llc_oui, sizeof(llc_oui));
418 		((__be16 *) here)[3] = skb->protocol;
419 	}
420 	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
421 	ATM_SKB(skb)->atm_options = vcc->atm_options;
422 	entry->vccs->last_use = jiffies;
423 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
424 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
425 	if (old) {
426 		pr_warning("XOFF->XOFF transition\n");
427 		return NETDEV_TX_OK;
428 	}
429 	dev->stats.tx_packets++;
430 	dev->stats.tx_bytes += skb->len;
431 	vcc->send(vcc, skb);
432 	if (atm_may_send(vcc, 0)) {
433 		entry->vccs->xoff = 0;
434 		return NETDEV_TX_OK;
435 	}
436 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
437 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
438 	barrier();
439 	if (!entry->vccs->xoff)
440 		netif_start_queue(dev);
441 	/* Oh, we just raced with clip_pop. netif_start_queue should be
442 	   good enough, because nothing should really be asleep because
443 	   of the brief netif_stop_queue. If this isn't true or if it
444 	   changes, use netif_wake_queue instead. */
445 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
446 	return NETDEV_TX_OK;
447 }
448 
449 static int clip_mkip(struct atm_vcc *vcc, int timeout)
450 {
451 	struct sk_buff_head *rq, queue;
452 	struct clip_vcc *clip_vcc;
453 	struct sk_buff *skb, *tmp;
454 	unsigned long flags;
455 
456 	if (!vcc->push)
457 		return -EBADFD;
458 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
459 	if (!clip_vcc)
460 		return -ENOMEM;
461 	pr_debug("%p vcc %p\n", clip_vcc, vcc);
462 	clip_vcc->vcc = vcc;
463 	vcc->user_back = clip_vcc;
464 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
465 	clip_vcc->entry = NULL;
466 	clip_vcc->xoff = 0;
467 	clip_vcc->encap = 1;
468 	clip_vcc->last_use = jiffies;
469 	clip_vcc->idle_timeout = timeout * HZ;
470 	clip_vcc->old_push = vcc->push;
471 	clip_vcc->old_pop = vcc->pop;
472 	vcc->push = clip_push;
473 	vcc->pop = clip_pop;
474 
475 	__skb_queue_head_init(&queue);
476 	rq = &sk_atm(vcc)->sk_receive_queue;
477 
478 	spin_lock_irqsave(&rq->lock, flags);
479 	skb_queue_splice_init(rq, &queue);
480 	spin_unlock_irqrestore(&rq->lock, flags);
481 
482 	/* re-process everything received between connection setup and MKIP */
483 	skb_queue_walk_safe(&queue, skb, tmp) {
484 		if (!clip_devs) {
485 			atm_return(vcc, skb->truesize);
486 			kfree_skb(skb);
487 		} else {
488 			struct net_device *dev = skb->dev;
489 			unsigned int len = skb->len;
490 
491 			skb_get(skb);
492 			clip_push(vcc, skb);
493 			dev->stats.rx_packets--;
494 			dev->stats.rx_bytes -= len;
495 			kfree_skb(skb);
496 		}
497 	}
498 	return 0;
499 }
500 
501 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
502 {
503 	struct neighbour *neigh;
504 	struct atmarp_entry *entry;
505 	int error;
506 	struct clip_vcc *clip_vcc;
507 	struct rtable *rt;
508 
509 	if (vcc->push != clip_push) {
510 		pr_warning("non-CLIP VCC\n");
511 		return -EBADF;
512 	}
513 	clip_vcc = CLIP_VCC(vcc);
514 	if (!ip) {
515 		if (!clip_vcc->entry) {
516 			pr_err("hiding hidden ATMARP entry\n");
517 			return 0;
518 		}
519 		pr_debug("remove\n");
520 		unlink_clip_vcc(clip_vcc);
521 		return 0;
522 	}
523 	rt = ip_route_output(&init_net, ip, 0, 1, 0);
524 	if (IS_ERR(rt))
525 		return PTR_ERR(rt);
526 	neigh = __neigh_lookup(&clip_tbl, &ip, rt->dst.dev, 1);
527 	ip_rt_put(rt);
528 	if (!neigh)
529 		return -ENOMEM;
530 	entry = NEIGH2ENTRY(neigh);
531 	if (entry != clip_vcc->entry) {
532 		if (!clip_vcc->entry)
533 			pr_debug("add\n");
534 		else {
535 			pr_debug("update\n");
536 			unlink_clip_vcc(clip_vcc);
537 		}
538 		link_vcc(clip_vcc, entry);
539 	}
540 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
541 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
542 	neigh_release(neigh);
543 	return error;
544 }
545 
546 static const struct net_device_ops clip_netdev_ops = {
547 	.ndo_start_xmit = clip_start_xmit,
548 };
549 
550 static void clip_setup(struct net_device *dev)
551 {
552 	dev->netdev_ops = &clip_netdev_ops;
553 	dev->type = ARPHRD_ATM;
554 	dev->hard_header_len = RFC1483LLC_LEN;
555 	dev->mtu = RFC1626_MTU;
556 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
557 	/* When using a "real" qdisc, the qdisc determines the queue */
558 	/* length. tx_queue_len is only used for the default case, */
559 	/* without any more elaborate queuing. 100 is a reasonable */
560 	/* compromise between decent burst-tolerance and protection */
561 	/* against memory hogs. */
562 	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
563 }
564 
565 static int clip_create(int number)
566 {
567 	struct net_device *dev;
568 	struct clip_priv *clip_priv;
569 	int error;
570 
571 	if (number != -1) {
572 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
573 			if (PRIV(dev)->number == number)
574 				return -EEXIST;
575 	} else {
576 		number = 0;
577 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
578 			if (PRIV(dev)->number >= number)
579 				number = PRIV(dev)->number + 1;
580 	}
581 	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
582 	if (!dev)
583 		return -ENOMEM;
584 	clip_priv = PRIV(dev);
585 	sprintf(dev->name, "atm%d", number);
586 	spin_lock_init(&clip_priv->xoff_lock);
587 	clip_priv->number = number;
588 	error = register_netdev(dev);
589 	if (error) {
590 		free_netdev(dev);
591 		return error;
592 	}
593 	clip_priv->next = clip_devs;
594 	clip_devs = dev;
595 	pr_debug("registered (net:%s)\n", dev->name);
596 	return number;
597 }
598 
599 static int clip_device_event(struct notifier_block *this, unsigned long event,
600 			     void *arg)
601 {
602 	struct net_device *dev = arg;
603 
604 	if (!net_eq(dev_net(dev), &init_net))
605 		return NOTIFY_DONE;
606 
607 	if (event == NETDEV_UNREGISTER) {
608 		neigh_ifdown(&clip_tbl, dev);
609 		return NOTIFY_DONE;
610 	}
611 
612 	/* ignore non-CLIP devices */
613 	if (dev->type != ARPHRD_ATM || dev->netdev_ops != &clip_netdev_ops)
614 		return NOTIFY_DONE;
615 
616 	switch (event) {
617 	case NETDEV_UP:
618 		pr_debug("NETDEV_UP\n");
619 		to_atmarpd(act_up, PRIV(dev)->number, 0);
620 		break;
621 	case NETDEV_GOING_DOWN:
622 		pr_debug("NETDEV_DOWN\n");
623 		to_atmarpd(act_down, PRIV(dev)->number, 0);
624 		break;
625 	case NETDEV_CHANGE:
626 	case NETDEV_CHANGEMTU:
627 		pr_debug("NETDEV_CHANGE*\n");
628 		to_atmarpd(act_change, PRIV(dev)->number, 0);
629 		break;
630 	}
631 	return NOTIFY_DONE;
632 }
633 
634 static int clip_inet_event(struct notifier_block *this, unsigned long event,
635 			   void *ifa)
636 {
637 	struct in_device *in_dev;
638 
639 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
640 	/*
641 	 * Transitions are of the down-change-up type, so it's sufficient to
642 	 * handle the change on up.
643 	 */
644 	if (event != NETDEV_UP)
645 		return NOTIFY_DONE;
646 	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
647 }
648 
649 static struct notifier_block clip_dev_notifier = {
650 	.notifier_call = clip_device_event,
651 };
652 
653 
654 
655 static struct notifier_block clip_inet_notifier = {
656 	.notifier_call = clip_inet_event,
657 };
658 
659 
660 
661 static void atmarpd_close(struct atm_vcc *vcc)
662 {
663 	pr_debug("\n");
664 
665 	rtnl_lock();
666 	atmarpd = NULL;
667 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
668 	rtnl_unlock();
669 
670 	pr_debug("(done)\n");
671 	module_put(THIS_MODULE);
672 }
673 
674 static struct atmdev_ops atmarpd_dev_ops = {
675 	.close = atmarpd_close
676 };
677 
678 
679 static struct atm_dev atmarpd_dev = {
680 	.ops =			&atmarpd_dev_ops,
681 	.type =			"arpd",
682 	.number = 		999,
683 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
684 };
685 
686 
687 static int atm_init_atmarp(struct atm_vcc *vcc)
688 {
689 	rtnl_lock();
690 	if (atmarpd) {
691 		rtnl_unlock();
692 		return -EADDRINUSE;
693 	}
694 
695 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
696 
697 	atmarpd = vcc;
698 	set_bit(ATM_VF_META, &vcc->flags);
699 	set_bit(ATM_VF_READY, &vcc->flags);
700 	    /* allow replies and avoid getting closed if signaling dies */
701 	vcc->dev = &atmarpd_dev;
702 	vcc_insert_socket(sk_atm(vcc));
703 	vcc->push = NULL;
704 	vcc->pop = NULL; /* crash */
705 	vcc->push_oam = NULL; /* crash */
706 	rtnl_unlock();
707 	return 0;
708 }
709 
710 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
711 {
712 	struct atm_vcc *vcc = ATM_SD(sock);
713 	int err = 0;
714 
715 	switch (cmd) {
716 	case SIOCMKCLIP:
717 	case ATMARPD_CTRL:
718 	case ATMARP_MKIP:
719 	case ATMARP_SETENTRY:
720 	case ATMARP_ENCAP:
721 		if (!capable(CAP_NET_ADMIN))
722 			return -EPERM;
723 		break;
724 	default:
725 		return -ENOIOCTLCMD;
726 	}
727 
728 	switch (cmd) {
729 	case SIOCMKCLIP:
730 		err = clip_create(arg);
731 		break;
732 	case ATMARPD_CTRL:
733 		err = atm_init_atmarp(vcc);
734 		if (!err) {
735 			sock->state = SS_CONNECTED;
736 			__module_get(THIS_MODULE);
737 		}
738 		break;
739 	case ATMARP_MKIP:
740 		err = clip_mkip(vcc, arg);
741 		break;
742 	case ATMARP_SETENTRY:
743 		err = clip_setentry(vcc, (__force __be32)arg);
744 		break;
745 	case ATMARP_ENCAP:
746 		err = clip_encap(vcc, arg);
747 		break;
748 	}
749 	return err;
750 }
751 
752 static struct atm_ioctl clip_ioctl_ops = {
753 	.owner = THIS_MODULE,
754 	.ioctl = clip_ioctl,
755 };
756 
757 #ifdef CONFIG_PROC_FS
758 
759 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
760 {
761 	static int code[] = { 1, 2, 10, 6, 1, 0 };
762 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
763 
764 	if (*addr->sas_addr.pub) {
765 		seq_printf(seq, "%s", addr->sas_addr.pub);
766 		if (*addr->sas_addr.prv)
767 			seq_putc(seq, '+');
768 	} else if (!*addr->sas_addr.prv) {
769 		seq_printf(seq, "%s", "(none)");
770 		return;
771 	}
772 	if (*addr->sas_addr.prv) {
773 		unsigned char *prv = addr->sas_addr.prv;
774 		int *fields;
775 		int i, j;
776 
777 		fields = *prv == ATM_AFI_E164 ? e164 : code;
778 		for (i = 0; fields[i]; i++) {
779 			for (j = fields[i]; j; j--)
780 				seq_printf(seq, "%02X", *prv++);
781 			if (fields[i + 1])
782 				seq_putc(seq, '.');
783 		}
784 	}
785 }
786 
787 /* This means the neighbour entry has no attached VCC objects. */
788 #define SEQ_NO_VCC_TOKEN	((void *) 2)
789 
790 static void atmarp_info(struct seq_file *seq, struct net_device *dev,
791 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
792 {
793 	unsigned long exp;
794 	char buf[17];
795 	int svc, llc, off;
796 
797 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
798 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
799 
800 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
801 
802 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
803 		exp = entry->neigh->used;
804 	else
805 		exp = clip_vcc->last_use;
806 
807 	exp = (jiffies - exp) / HZ;
808 
809 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
810 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
811 
812 	off = scnprintf(buf, sizeof(buf) - 1, "%pI4",
813 			&entry->ip);
814 	while (off < 16)
815 		buf[off++] = ' ';
816 	buf[off] = '\0';
817 	seq_printf(seq, "%s", buf);
818 
819 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
820 		if (time_before(jiffies, entry->expires))
821 			seq_printf(seq, "(resolving)\n");
822 		else
823 			seq_printf(seq, "(expired, ref %d)\n",
824 				   atomic_read(&entry->neigh->refcnt));
825 	} else if (!svc) {
826 		seq_printf(seq, "%d.%d.%d\n",
827 			   clip_vcc->vcc->dev->number,
828 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
829 	} else {
830 		svc_addr(seq, &clip_vcc->vcc->remote);
831 		seq_putc(seq, '\n');
832 	}
833 }
834 
835 struct clip_seq_state {
836 	/* This member must be first. */
837 	struct neigh_seq_state ns;
838 
839 	/* Local to clip specific iteration. */
840 	struct clip_vcc *vcc;
841 };
842 
843 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
844 					  struct clip_vcc *curr)
845 {
846 	if (!curr) {
847 		curr = e->vccs;
848 		if (!curr)
849 			return SEQ_NO_VCC_TOKEN;
850 		return curr;
851 	}
852 	if (curr == SEQ_NO_VCC_TOKEN)
853 		return NULL;
854 
855 	curr = curr->next;
856 
857 	return curr;
858 }
859 
860 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
861 			       struct atmarp_entry *e, loff_t * pos)
862 {
863 	struct clip_vcc *vcc = state->vcc;
864 
865 	vcc = clip_seq_next_vcc(e, vcc);
866 	if (vcc && pos != NULL) {
867 		while (*pos) {
868 			vcc = clip_seq_next_vcc(e, vcc);
869 			if (!vcc)
870 				break;
871 			--(*pos);
872 		}
873 	}
874 	state->vcc = vcc;
875 
876 	return vcc;
877 }
878 
879 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
880 			       struct neighbour *n, loff_t * pos)
881 {
882 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
883 
884 	return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
885 }
886 
887 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
888 {
889 	struct clip_seq_state *state = seq->private;
890 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
891 	return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
892 }
893 
894 static int clip_seq_show(struct seq_file *seq, void *v)
895 {
896 	static char atm_arp_banner[] =
897 	    "IPitf TypeEncp Idle IP address      ATM address\n";
898 
899 	if (v == SEQ_START_TOKEN) {
900 		seq_puts(seq, atm_arp_banner);
901 	} else {
902 		struct clip_seq_state *state = seq->private;
903 		struct neighbour *n = v;
904 		struct clip_vcc *vcc = state->vcc;
905 
906 		atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);
907 	}
908 	return 0;
909 }
910 
911 static const struct seq_operations arp_seq_ops = {
912 	.start	= clip_seq_start,
913 	.next	= neigh_seq_next,
914 	.stop	= neigh_seq_stop,
915 	.show	= clip_seq_show,
916 };
917 
918 static int arp_seq_open(struct inode *inode, struct file *file)
919 {
920 	return seq_open_net(inode, file, &arp_seq_ops,
921 			    sizeof(struct clip_seq_state));
922 }
923 
924 static const struct file_operations arp_seq_fops = {
925 	.open		= arp_seq_open,
926 	.read		= seq_read,
927 	.llseek		= seq_lseek,
928 	.release	= seq_release_net,
929 	.owner		= THIS_MODULE
930 };
931 #endif
932 
933 static void atm_clip_exit_noproc(void);
934 
935 static int __init atm_clip_init(void)
936 {
937 	neigh_table_init_no_netlink(&clip_tbl);
938 
939 	clip_tbl_hook = &clip_tbl;
940 	register_atm_ioctl(&clip_ioctl_ops);
941 	register_netdevice_notifier(&clip_dev_notifier);
942 	register_inetaddr_notifier(&clip_inet_notifier);
943 
944 	setup_timer(&idle_timer, idle_timer_check, 0);
945 
946 #ifdef CONFIG_PROC_FS
947 	{
948 		struct proc_dir_entry *p;
949 
950 		p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
951 		if (!p) {
952 			pr_err("Unable to initialize /proc/net/atm/arp\n");
953 			atm_clip_exit_noproc();
954 			return -ENOMEM;
955 		}
956 	}
957 #endif
958 
959 	return 0;
960 }
961 
962 static void atm_clip_exit_noproc(void)
963 {
964 	struct net_device *dev, *next;
965 
966 	unregister_inetaddr_notifier(&clip_inet_notifier);
967 	unregister_netdevice_notifier(&clip_dev_notifier);
968 
969 	deregister_atm_ioctl(&clip_ioctl_ops);
970 
971 	/* First, stop the idle timer, so it stops banging
972 	 * on the table.
973 	 */
974 	del_timer_sync(&idle_timer);
975 
976 	/* Next, purge the table, so that the device
977 	 * unregister loop below does not hang due to
978 	 * device references remaining in the table.
979 	 */
980 	neigh_ifdown(&clip_tbl, NULL);
981 
982 	dev = clip_devs;
983 	while (dev) {
984 		next = PRIV(dev)->next;
985 		unregister_netdev(dev);
986 		free_netdev(dev);
987 		dev = next;
988 	}
989 
990 	/* Now it is safe to fully shutdown whole table. */
991 	neigh_table_clear(&clip_tbl);
992 
993 	clip_tbl_hook = NULL;
994 }
995 
996 static void __exit atm_clip_exit(void)
997 {
998 	remove_proc_entry("arp", atm_proc_root);
999 
1000 	atm_clip_exit_noproc();
1001 }
1002 
1003 module_init(atm_clip_init);
1004 module_exit(atm_clip_exit);
1005 MODULE_AUTHOR("Werner Almesberger");
1006 MODULE_DESCRIPTION("Classical/IP over ATM interface");
1007 MODULE_LICENSE("GPL");
1008