xref: /linux/net/atm/clip.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b)
1 /* net/atm/clip.c - RFC1577 Classical IP over ATM */
2 
3 /* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
4 
5 #include <linux/string.h>
6 #include <linux/errno.h>
7 #include <linux/kernel.h> /* for UINT_MAX */
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/netdevice.h>
11 #include <linux/skbuff.h>
12 #include <linux/wait.h>
13 #include <linux/timer.h>
14 #include <linux/if_arp.h> /* for some manifest constants */
15 #include <linux/notifier.h>
16 #include <linux/atm.h>
17 #include <linux/atmdev.h>
18 #include <linux/atmclip.h>
19 #include <linux/atmarp.h>
20 #include <linux/capability.h>
21 #include <linux/ip.h> /* for net/route.h */
22 #include <linux/in.h> /* for struct sockaddr_in */
23 #include <linux/if.h> /* for IFF_UP */
24 #include <linux/inetdevice.h>
25 #include <linux/bitops.h>
26 #include <linux/poison.h>
27 #include <linux/proc_fs.h>
28 #include <linux/seq_file.h>
29 #include <linux/rcupdate.h>
30 #include <linux/jhash.h>
31 #include <net/route.h> /* for struct rtable and routing */
32 #include <net/icmp.h> /* icmp_send */
33 #include <asm/param.h> /* for HZ */
34 #include <asm/byteorder.h> /* for htons etc. */
35 #include <asm/system.h> /* save/restore_flags */
36 #include <asm/uaccess.h>
37 #include <asm/atomic.h>
38 
39 #include "common.h"
40 #include "resources.h"
41 #include <net/atmclip.h>
42 
43 static struct net_device *clip_devs;
44 static struct atm_vcc *atmarpd;
45 static struct neigh_table clip_tbl;
46 static struct timer_list idle_timer;
47 
48 static int to_atmarpd(enum atmarp_ctrl_type type, int itf, __be32 ip)
49 {
50 	struct sock *sk;
51 	struct atmarp_ctrl *ctrl;
52 	struct sk_buff *skb;
53 
54 	pr_debug("to_atmarpd(%d)\n", type);
55 	if (!atmarpd)
56 		return -EUNATCH;
57 	skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);
58 	if (!skb)
59 		return -ENOMEM;
60 	ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));
61 	ctrl->type = type;
62 	ctrl->itf_num = itf;
63 	ctrl->ip = ip;
64 	atm_force_charge(atmarpd, skb->truesize);
65 
66 	sk = sk_atm(atmarpd);
67 	skb_queue_tail(&sk->sk_receive_queue, skb);
68 	sk->sk_data_ready(sk, skb->len);
69 	return 0;
70 }
71 
72 static void link_vcc(struct clip_vcc *clip_vcc, struct atmarp_entry *entry)
73 {
74 	pr_debug("link_vcc %p to entry %p (neigh %p)\n", clip_vcc, entry,
75 		entry->neigh);
76 	clip_vcc->entry = entry;
77 	clip_vcc->xoff = 0;	/* @@@ may overrun buffer by one packet */
78 	clip_vcc->next = entry->vccs;
79 	entry->vccs = clip_vcc;
80 	entry->neigh->used = jiffies;
81 }
82 
83 static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
84 {
85 	struct atmarp_entry *entry = clip_vcc->entry;
86 	struct clip_vcc **walk;
87 
88 	if (!entry) {
89 		printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n", clip_vcc);
90 		return;
91 	}
92 	netif_tx_lock_bh(entry->neigh->dev);	/* block clip_start_xmit() */
93 	entry->neigh->used = jiffies;
94 	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
95 		if (*walk == clip_vcc) {
96 			int error;
97 
98 			*walk = clip_vcc->next;	/* atomic */
99 			clip_vcc->entry = NULL;
100 			if (clip_vcc->xoff)
101 				netif_wake_queue(entry->neigh->dev);
102 			if (entry->vccs)
103 				goto out;
104 			entry->expires = jiffies - 1;
105 			/* force resolution or expiration */
106 			error = neigh_update(entry->neigh, NULL, NUD_NONE,
107 					     NEIGH_UPDATE_F_ADMIN);
108 			if (error)
109 				printk(KERN_CRIT "unlink_clip_vcc: "
110 				       "neigh_update failed with %d\n", error);
111 			goto out;
112 		}
113 	printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "
114 	       "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("clip_arp_rcv\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("clip push\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 			PRIV(skb->dev)->stats.rx_packets++;
218 			PRIV(skb->dev)->stats.rx_bytes += skb->len;
219 			clip_arp_rcv(skb);
220 			return;
221 		}
222 	}
223 	clip_vcc->last_use = jiffies;
224 	PRIV(skb->dev)->stats.rx_packets++;
225 	PRIV(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("clip_pop(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("clip_neigh_solicit (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 struct neigh_ops clip_neigh_ops = {
271 	.family =		AF_INET,
272 	.solicit =		clip_neigh_solicit,
273 	.error_report =		clip_neigh_error,
274 	.output =		dev_queue_xmit,
275 	.connected_output =	dev_queue_xmit,
276 	.hh_output =		dev_queue_xmit,
277 	.queue_xmit =		dev_queue_xmit,
278 };
279 
280 static int clip_constructor(struct neighbour *neigh)
281 {
282 	struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
283 	struct net_device *dev = neigh->dev;
284 	struct in_device *in_dev;
285 	struct neigh_parms *parms;
286 
287 	pr_debug("clip_constructor (neigh %p, entry %p)\n", neigh, entry);
288 	neigh->type = inet_addr_type(&init_net, entry->ip);
289 	if (neigh->type != RTN_UNICAST)
290 		return -EINVAL;
291 
292 	rcu_read_lock();
293 	in_dev = __in_dev_get_rcu(dev);
294 	if (!in_dev) {
295 		rcu_read_unlock();
296 		return -EINVAL;
297 	}
298 
299 	parms = in_dev->arp_parms;
300 	__neigh_parms_put(neigh->parms);
301 	neigh->parms = neigh_parms_clone(parms);
302 	rcu_read_unlock();
303 
304 	neigh->ops = &clip_neigh_ops;
305 	neigh->output = neigh->nud_state & NUD_VALID ?
306 	    neigh->ops->connected_output : neigh->ops->output;
307 	entry->neigh = neigh;
308 	entry->vccs = NULL;
309 	entry->expires = jiffies - 1;
310 	return 0;
311 }
312 
313 static u32 clip_hash(const void *pkey, const struct net_device *dev)
314 {
315 	return jhash_2words(*(u32 *) pkey, dev->ifindex, clip_tbl.hash_rnd);
316 }
317 
318 static struct neigh_table clip_tbl = {
319 	.family 	= AF_INET,
320 	.entry_size 	= sizeof(struct neighbour)+sizeof(struct atmarp_entry),
321 	.key_len 	= 4,
322 	.hash 		= clip_hash,
323 	.constructor 	= clip_constructor,
324 	.id 		= "clip_arp_cache",
325 
326 	/* parameters are copied from ARP ... */
327 	.parms = {
328 		.tbl 			= &clip_tbl,
329 		.base_reachable_time 	= 30 * HZ,
330 		.retrans_time 		= 1 * HZ,
331 		.gc_staletime 		= 60 * HZ,
332 		.reachable_time 	= 30 * HZ,
333 		.delay_probe_time 	= 5 * HZ,
334 		.queue_len 		= 3,
335 		.ucast_probes 		= 3,
336 		.mcast_probes 		= 3,
337 		.anycast_delay 		= 1 * HZ,
338 		.proxy_delay 		= (8 * HZ) / 10,
339 		.proxy_qlen 		= 64,
340 		.locktime 		= 1 * HZ,
341 	},
342 	.gc_interval 	= 30 * HZ,
343 	.gc_thresh1 	= 128,
344 	.gc_thresh2 	= 512,
345 	.gc_thresh3 	= 1024,
346 };
347 
348 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
349 
350 /*
351  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
352  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
353  * don't increment the usage count. This is used to create entries in
354  * clip_setentry.
355  */
356 
357 static int clip_encap(struct atm_vcc *vcc, int mode)
358 {
359 	CLIP_VCC(vcc)->encap = mode;
360 	return 0;
361 }
362 
363 static int clip_start_xmit(struct sk_buff *skb, struct net_device *dev)
364 {
365 	struct clip_priv *clip_priv = PRIV(dev);
366 	struct atmarp_entry *entry;
367 	struct atm_vcc *vcc;
368 	int old;
369 	unsigned long flags;
370 
371 	pr_debug("clip_start_xmit (skb %p)\n", skb);
372 	if (!skb->dst) {
373 		printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");
374 		dev_kfree_skb(skb);
375 		clip_priv->stats.tx_dropped++;
376 		return 0;
377 	}
378 	if (!skb->dst->neighbour) {
379 #if 0
380 		skb->dst->neighbour = clip_find_neighbour(skb->dst, 1);
381 		if (!skb->dst->neighbour) {
382 			dev_kfree_skb(skb);	/* lost that one */
383 			clip_priv->stats.tx_dropped++;
384 			return 0;
385 		}
386 #endif
387 		printk(KERN_ERR "clip_start_xmit: NO NEIGHBOUR !\n");
388 		dev_kfree_skb(skb);
389 		clip_priv->stats.tx_dropped++;
390 		return 0;
391 	}
392 	entry = NEIGH2ENTRY(skb->dst->neighbour);
393 	if (!entry->vccs) {
394 		if (time_after(jiffies, entry->expires)) {
395 			/* should be resolved */
396 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
397 			to_atmarpd(act_need, PRIV(dev)->number, entry->ip);
398 		}
399 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
400 			skb_queue_tail(&entry->neigh->arp_queue, skb);
401 		else {
402 			dev_kfree_skb(skb);
403 			clip_priv->stats.tx_dropped++;
404 		}
405 		return 0;
406 	}
407 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
408 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
409 	pr_debug("using neighbour %p, vcc %p\n", skb->dst->neighbour, vcc);
410 	if (entry->vccs->encap) {
411 		void *here;
412 
413 		here = skb_push(skb, RFC1483LLC_LEN);
414 		memcpy(here, llc_oui, sizeof(llc_oui));
415 		((__be16 *) here)[3] = skb->protocol;
416 	}
417 	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
418 	ATM_SKB(skb)->atm_options = vcc->atm_options;
419 	entry->vccs->last_use = jiffies;
420 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
421 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
422 	if (old) {
423 		printk(KERN_WARNING "clip_start_xmit: XOFF->XOFF transition\n");
424 		return 0;
425 	}
426 	clip_priv->stats.tx_packets++;
427 	clip_priv->stats.tx_bytes += skb->len;
428 	vcc->send(vcc, skb);
429 	if (atm_may_send(vcc, 0)) {
430 		entry->vccs->xoff = 0;
431 		return 0;
432 	}
433 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
434 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
435 	barrier();
436 	if (!entry->vccs->xoff)
437 		netif_start_queue(dev);
438 	/* Oh, we just raced with clip_pop. netif_start_queue should be
439 	   good enough, because nothing should really be asleep because
440 	   of the brief netif_stop_queue. If this isn't true or if it
441 	   changes, use netif_wake_queue instead. */
442 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
443 	return 0;
444 }
445 
446 static struct net_device_stats *clip_get_stats(struct net_device *dev)
447 {
448 	return &PRIV(dev)->stats;
449 }
450 
451 static int clip_mkip(struct atm_vcc *vcc, int timeout)
452 {
453 	struct clip_vcc *clip_vcc;
454 	struct sk_buff *skb;
455 	struct sk_buff_head *rq;
456 	unsigned long flags;
457 
458 	if (!vcc->push)
459 		return -EBADFD;
460 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
461 	if (!clip_vcc)
462 		return -ENOMEM;
463 	pr_debug("mkip clip_vcc %p vcc %p\n", clip_vcc, vcc);
464 	clip_vcc->vcc = vcc;
465 	vcc->user_back = clip_vcc;
466 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
467 	clip_vcc->entry = NULL;
468 	clip_vcc->xoff = 0;
469 	clip_vcc->encap = 1;
470 	clip_vcc->last_use = jiffies;
471 	clip_vcc->idle_timeout = timeout * HZ;
472 	clip_vcc->old_push = vcc->push;
473 	clip_vcc->old_pop = vcc->pop;
474 	vcc->push = clip_push;
475 	vcc->pop = clip_pop;
476 
477 	rq = &sk_atm(vcc)->sk_receive_queue;
478 
479 	spin_lock_irqsave(&rq->lock, flags);
480 	if (skb_queue_empty(rq)) {
481 		skb = NULL;
482 	} else {
483 		/* NULL terminate the list.  */
484 		rq->prev->next = NULL;
485 		skb = rq->next;
486 	}
487 	rq->prev = rq->next = (struct sk_buff *)rq;
488 	rq->qlen = 0;
489 	spin_unlock_irqrestore(&rq->lock, flags);
490 
491 	/* re-process everything received between connection setup and MKIP */
492 	while (skb) {
493 		struct sk_buff *next = skb->next;
494 
495 		skb->next = skb->prev = NULL;
496 		if (!clip_devs) {
497 			atm_return(vcc, skb->truesize);
498 			kfree_skb(skb);
499 		} else {
500 			unsigned int len = skb->len;
501 
502 			skb_get(skb);
503 			clip_push(vcc, skb);
504 			PRIV(skb->dev)->stats.rx_packets--;
505 			PRIV(skb->dev)->stats.rx_bytes -= len;
506 			kfree_skb(skb);
507 		}
508 
509 		skb = next;
510 	}
511 	return 0;
512 }
513 
514 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
515 {
516 	struct neighbour *neigh;
517 	struct atmarp_entry *entry;
518 	int error;
519 	struct clip_vcc *clip_vcc;
520 	struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, .tos = 1}} };
521 	struct rtable *rt;
522 
523 	if (vcc->push != clip_push) {
524 		printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");
525 		return -EBADF;
526 	}
527 	clip_vcc = CLIP_VCC(vcc);
528 	if (!ip) {
529 		if (!clip_vcc->entry) {
530 			printk(KERN_ERR "hiding hidden ATMARP entry\n");
531 			return 0;
532 		}
533 		pr_debug("setentry: remove\n");
534 		unlink_clip_vcc(clip_vcc);
535 		return 0;
536 	}
537 	error = ip_route_output_key(&init_net, &rt, &fl);
538 	if (error)
539 		return error;
540 	neigh = __neigh_lookup(&clip_tbl, &ip, rt->u.dst.dev, 1);
541 	ip_rt_put(rt);
542 	if (!neigh)
543 		return -ENOMEM;
544 	entry = NEIGH2ENTRY(neigh);
545 	if (entry != clip_vcc->entry) {
546 		if (!clip_vcc->entry)
547 			pr_debug("setentry: add\n");
548 		else {
549 			pr_debug("setentry: update\n");
550 			unlink_clip_vcc(clip_vcc);
551 		}
552 		link_vcc(clip_vcc, entry);
553 	}
554 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
555 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
556 	neigh_release(neigh);
557 	return error;
558 }
559 
560 static void clip_setup(struct net_device *dev)
561 {
562 	dev->hard_start_xmit = clip_start_xmit;
563 	/* sg_xmit ... */
564 	dev->get_stats = clip_get_stats;
565 	dev->type = ARPHRD_ATM;
566 	dev->hard_header_len = RFC1483LLC_LEN;
567 	dev->mtu = RFC1626_MTU;
568 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
569 	/* When using a "real" qdisc, the qdisc determines the queue */
570 	/* length. tx_queue_len is only used for the default case, */
571 	/* without any more elaborate queuing. 100 is a reasonable */
572 	/* compromise between decent burst-tolerance and protection */
573 	/* against memory hogs. */
574 }
575 
576 static int clip_create(int number)
577 {
578 	struct net_device *dev;
579 	struct clip_priv *clip_priv;
580 	int error;
581 
582 	if (number != -1) {
583 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
584 			if (PRIV(dev)->number == number)
585 				return -EEXIST;
586 	} else {
587 		number = 0;
588 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
589 			if (PRIV(dev)->number >= number)
590 				number = PRIV(dev)->number + 1;
591 	}
592 	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
593 	if (!dev)
594 		return -ENOMEM;
595 	clip_priv = PRIV(dev);
596 	sprintf(dev->name, "atm%d", number);
597 	spin_lock_init(&clip_priv->xoff_lock);
598 	clip_priv->number = number;
599 	error = register_netdev(dev);
600 	if (error) {
601 		free_netdev(dev);
602 		return error;
603 	}
604 	clip_priv->next = clip_devs;
605 	clip_devs = dev;
606 	pr_debug("registered (net:%s)\n", dev->name);
607 	return number;
608 }
609 
610 static int clip_device_event(struct notifier_block *this, unsigned long event,
611 			     void *arg)
612 {
613 	struct net_device *dev = arg;
614 
615 	if (!net_eq(dev_net(dev), &init_net))
616 		return NOTIFY_DONE;
617 
618 	if (event == NETDEV_UNREGISTER) {
619 		neigh_ifdown(&clip_tbl, dev);
620 		return NOTIFY_DONE;
621 	}
622 
623 	/* ignore non-CLIP devices */
624 	if (dev->type != ARPHRD_ATM || dev->hard_start_xmit != clip_start_xmit)
625 		return NOTIFY_DONE;
626 
627 	switch (event) {
628 	case NETDEV_UP:
629 		pr_debug("clip_device_event NETDEV_UP\n");
630 		to_atmarpd(act_up, PRIV(dev)->number, 0);
631 		break;
632 	case NETDEV_GOING_DOWN:
633 		pr_debug("clip_device_event NETDEV_DOWN\n");
634 		to_atmarpd(act_down, PRIV(dev)->number, 0);
635 		break;
636 	case NETDEV_CHANGE:
637 	case NETDEV_CHANGEMTU:
638 		pr_debug("clip_device_event NETDEV_CHANGE*\n");
639 		to_atmarpd(act_change, PRIV(dev)->number, 0);
640 		break;
641 	}
642 	return NOTIFY_DONE;
643 }
644 
645 static int clip_inet_event(struct notifier_block *this, unsigned long event,
646 			   void *ifa)
647 {
648 	struct in_device *in_dev;
649 
650 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
651 	/*
652 	 * Transitions are of the down-change-up type, so it's sufficient to
653 	 * handle the change on up.
654 	 */
655 	if (event != NETDEV_UP)
656 		return NOTIFY_DONE;
657 	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
658 }
659 
660 
661 static struct notifier_block clip_dev_notifier = {
662 	.notifier_call = clip_device_event,
663 };
664 
665 
666 
667 static struct notifier_block clip_inet_notifier = {
668 	.notifier_call = clip_inet_event,
669 };
670 
671 
672 
673 static void atmarpd_close(struct atm_vcc *vcc)
674 {
675 	pr_debug("atmarpd_close\n");
676 
677 	rtnl_lock();
678 	atmarpd = NULL;
679 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
680 	rtnl_unlock();
681 
682 	pr_debug("(done)\n");
683 	module_put(THIS_MODULE);
684 }
685 
686 
687 static struct atmdev_ops atmarpd_dev_ops = {
688 	.close = atmarpd_close
689 };
690 
691 
692 static struct atm_dev atmarpd_dev = {
693 	.ops =			&atmarpd_dev_ops,
694 	.type =			"arpd",
695 	.number = 		999,
696 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
697 };
698 
699 
700 static int atm_init_atmarp(struct atm_vcc *vcc)
701 {
702 	rtnl_lock();
703 	if (atmarpd) {
704 		rtnl_unlock();
705 		return -EADDRINUSE;
706 	}
707 
708 	mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
709 
710 	atmarpd = vcc;
711 	set_bit(ATM_VF_META,&vcc->flags);
712 	set_bit(ATM_VF_READY,&vcc->flags);
713 	    /* allow replies and avoid getting closed if signaling dies */
714 	vcc->dev = &atmarpd_dev;
715 	vcc_insert_socket(sk_atm(vcc));
716 	vcc->push = NULL;
717 	vcc->pop = NULL; /* crash */
718 	vcc->push_oam = NULL; /* crash */
719 	rtnl_unlock();
720 	return 0;
721 }
722 
723 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
724 {
725 	struct atm_vcc *vcc = ATM_SD(sock);
726 	int err = 0;
727 
728 	switch (cmd) {
729 	case SIOCMKCLIP:
730 	case ATMARPD_CTRL:
731 	case ATMARP_MKIP:
732 	case ATMARP_SETENTRY:
733 	case ATMARP_ENCAP:
734 		if (!capable(CAP_NET_ADMIN))
735 			return -EPERM;
736 		break;
737 	default:
738 		return -ENOIOCTLCMD;
739 	}
740 
741 	switch (cmd) {
742 	case SIOCMKCLIP:
743 		err = clip_create(arg);
744 		break;
745 	case ATMARPD_CTRL:
746 		err = atm_init_atmarp(vcc);
747 		if (!err) {
748 			sock->state = SS_CONNECTED;
749 			__module_get(THIS_MODULE);
750 		}
751 		break;
752 	case ATMARP_MKIP:
753 		err = clip_mkip(vcc, arg);
754 		break;
755 	case ATMARP_SETENTRY:
756 		err = clip_setentry(vcc, (__force __be32)arg);
757 		break;
758 	case ATMARP_ENCAP:
759 		err = clip_encap(vcc, arg);
760 		break;
761 	}
762 	return err;
763 }
764 
765 static struct atm_ioctl clip_ioctl_ops = {
766 	.owner = THIS_MODULE,
767 	.ioctl = clip_ioctl,
768 };
769 
770 #ifdef CONFIG_PROC_FS
771 
772 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
773 {
774 	static int code[] = { 1, 2, 10, 6, 1, 0 };
775 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
776 
777 	if (*addr->sas_addr.pub) {
778 		seq_printf(seq, "%s", addr->sas_addr.pub);
779 		if (*addr->sas_addr.prv)
780 			seq_putc(seq, '+');
781 	} else if (!*addr->sas_addr.prv) {
782 		seq_printf(seq, "%s", "(none)");
783 		return;
784 	}
785 	if (*addr->sas_addr.prv) {
786 		unsigned char *prv = addr->sas_addr.prv;
787 		int *fields;
788 		int i, j;
789 
790 		fields = *prv == ATM_AFI_E164 ? e164 : code;
791 		for (i = 0; fields[i]; i++) {
792 			for (j = fields[i]; j; j--)
793 				seq_printf(seq, "%02X", *prv++);
794 			if (fields[i + 1])
795 				seq_putc(seq, '.');
796 		}
797 	}
798 }
799 
800 /* This means the neighbour entry has no attached VCC objects. */
801 #define SEQ_NO_VCC_TOKEN	((void *) 2)
802 
803 static void atmarp_info(struct seq_file *seq, struct net_device *dev,
804 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
805 {
806 	unsigned long exp;
807 	char buf[17];
808 	int svc, llc, off;
809 
810 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
811 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
812 
813 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
814 
815 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
816 		exp = entry->neigh->used;
817 	else
818 		exp = clip_vcc->last_use;
819 
820 	exp = (jiffies - exp) / HZ;
821 
822 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
823 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
824 
825 	off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d",
826 			NIPQUAD(entry->ip));
827 	while (off < 16)
828 		buf[off++] = ' ';
829 	buf[off] = '\0';
830 	seq_printf(seq, "%s", buf);
831 
832 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
833 		if (time_before(jiffies, entry->expires))
834 			seq_printf(seq, "(resolving)\n");
835 		else
836 			seq_printf(seq, "(expired, ref %d)\n",
837 				   atomic_read(&entry->neigh->refcnt));
838 	} else if (!svc) {
839 		seq_printf(seq, "%d.%d.%d\n",
840 			   clip_vcc->vcc->dev->number,
841 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
842 	} else {
843 		svc_addr(seq, &clip_vcc->vcc->remote);
844 		seq_putc(seq, '\n');
845 	}
846 }
847 
848 struct clip_seq_state {
849 	/* This member must be first. */
850 	struct neigh_seq_state ns;
851 
852 	/* Local to clip specific iteration. */
853 	struct clip_vcc *vcc;
854 };
855 
856 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
857 					  struct clip_vcc *curr)
858 {
859 	if (!curr) {
860 		curr = e->vccs;
861 		if (!curr)
862 			return SEQ_NO_VCC_TOKEN;
863 		return curr;
864 	}
865 	if (curr == SEQ_NO_VCC_TOKEN)
866 		return NULL;
867 
868 	curr = curr->next;
869 
870 	return curr;
871 }
872 
873 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
874 			       struct atmarp_entry *e, loff_t * pos)
875 {
876 	struct clip_vcc *vcc = state->vcc;
877 
878 	vcc = clip_seq_next_vcc(e, vcc);
879 	if (vcc && pos != NULL) {
880 		while (*pos) {
881 			vcc = clip_seq_next_vcc(e, vcc);
882 			if (!vcc)
883 				break;
884 			--(*pos);
885 		}
886 	}
887 	state->vcc = vcc;
888 
889 	return vcc;
890 }
891 
892 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
893 			       struct neighbour *n, loff_t * pos)
894 {
895 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
896 
897 	return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
898 }
899 
900 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
901 {
902 	struct clip_seq_state *state = seq->private;
903 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
904 	return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
905 }
906 
907 static int clip_seq_show(struct seq_file *seq, void *v)
908 {
909 	static char atm_arp_banner[] =
910 	    "IPitf TypeEncp Idle IP address      ATM address\n";
911 
912 	if (v == SEQ_START_TOKEN) {
913 		seq_puts(seq, atm_arp_banner);
914 	} else {
915 		struct clip_seq_state *state = seq->private;
916 		struct neighbour *n = v;
917 		struct clip_vcc *vcc = state->vcc;
918 
919 		atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);
920 	}
921 	return 0;
922 }
923 
924 static const struct seq_operations arp_seq_ops = {
925 	.start	= clip_seq_start,
926 	.next	= neigh_seq_next,
927 	.stop	= neigh_seq_stop,
928 	.show	= clip_seq_show,
929 };
930 
931 static int arp_seq_open(struct inode *inode, struct file *file)
932 {
933 	return seq_open_net(inode, file, &arp_seq_ops,
934 			    sizeof(struct clip_seq_state));
935 }
936 
937 static const struct file_operations arp_seq_fops = {
938 	.open		= arp_seq_open,
939 	.read		= seq_read,
940 	.llseek		= seq_lseek,
941 	.release	= seq_release_net,
942 	.owner		= THIS_MODULE
943 };
944 #endif
945 
946 static void atm_clip_exit_noproc(void);
947 
948 static int __init atm_clip_init(void)
949 {
950 	neigh_table_init_no_netlink(&clip_tbl);
951 
952 	clip_tbl_hook = &clip_tbl;
953 	register_atm_ioctl(&clip_ioctl_ops);
954 	register_netdevice_notifier(&clip_dev_notifier);
955 	register_inetaddr_notifier(&clip_inet_notifier);
956 
957 	setup_timer(&idle_timer, idle_timer_check, 0);
958 
959 #ifdef CONFIG_PROC_FS
960 	{
961 		struct proc_dir_entry *p;
962 
963 		p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
964 		if (!p) {
965 			printk(KERN_ERR "Unable to initialize "
966 			       "/proc/net/atm/arp\n");
967 			atm_clip_exit_noproc();
968 			return -ENOMEM;
969 		}
970 	}
971 #endif
972 
973 	return 0;
974 }
975 
976 static void atm_clip_exit_noproc(void)
977 {
978 	struct net_device *dev, *next;
979 
980 	unregister_inetaddr_notifier(&clip_inet_notifier);
981 	unregister_netdevice_notifier(&clip_dev_notifier);
982 
983 	deregister_atm_ioctl(&clip_ioctl_ops);
984 
985 	/* First, stop the idle timer, so it stops banging
986 	 * on the table.
987 	 */
988 	del_timer_sync(&idle_timer);
989 
990 	/* Next, purge the table, so that the device
991 	 * unregister loop below does not hang due to
992 	 * device references remaining in the table.
993 	 */
994 	neigh_ifdown(&clip_tbl, NULL);
995 
996 	dev = clip_devs;
997 	while (dev) {
998 		next = PRIV(dev)->next;
999 		unregister_netdev(dev);
1000 		free_netdev(dev);
1001 		dev = next;
1002 	}
1003 
1004 	/* Now it is safe to fully shutdown whole table. */
1005 	neigh_table_clear(&clip_tbl);
1006 
1007 	clip_tbl_hook = NULL;
1008 }
1009 
1010 static void __exit atm_clip_exit(void)
1011 {
1012 	remove_proc_entry("arp", atm_proc_root);
1013 
1014 	atm_clip_exit_noproc();
1015 }
1016 
1017 module_init(atm_clip_init);
1018 module_exit(atm_clip_exit);
1019 MODULE_AUTHOR("Werner Almesberger");
1020 MODULE_DESCRIPTION("Classical/IP over ATM interface");
1021 MODULE_LICENSE("GPL");
1022