xref: /openbmc/linux/net/atm/clip.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 
44 #if 0
45 #define DPRINTK(format,args...) printk(format,##args)
46 #else
47 #define DPRINTK(format,args...)
48 #endif
49 
50 
51 static struct net_device *clip_devs;
52 static struct atm_vcc *atmarpd;
53 static struct neigh_table clip_tbl;
54 static struct timer_list idle_timer;
55 
56 static int to_atmarpd(enum atmarp_ctrl_type type, int itf, __be32 ip)
57 {
58 	struct sock *sk;
59 	struct atmarp_ctrl *ctrl;
60 	struct sk_buff *skb;
61 
62 	DPRINTK("to_atmarpd(%d)\n", type);
63 	if (!atmarpd)
64 		return -EUNATCH;
65 	skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);
66 	if (!skb)
67 		return -ENOMEM;
68 	ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));
69 	ctrl->type = type;
70 	ctrl->itf_num = itf;
71 	ctrl->ip = ip;
72 	atm_force_charge(atmarpd, skb->truesize);
73 
74 	sk = sk_atm(atmarpd);
75 	skb_queue_tail(&sk->sk_receive_queue, skb);
76 	sk->sk_data_ready(sk, skb->len);
77 	return 0;
78 }
79 
80 static void link_vcc(struct clip_vcc *clip_vcc, struct atmarp_entry *entry)
81 {
82 	DPRINTK("link_vcc %p to entry %p (neigh %p)\n", clip_vcc, entry,
83 		entry->neigh);
84 	clip_vcc->entry = entry;
85 	clip_vcc->xoff = 0;	/* @@@ may overrun buffer by one packet */
86 	clip_vcc->next = entry->vccs;
87 	entry->vccs = clip_vcc;
88 	entry->neigh->used = jiffies;
89 }
90 
91 static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
92 {
93 	struct atmarp_entry *entry = clip_vcc->entry;
94 	struct clip_vcc **walk;
95 
96 	if (!entry) {
97 		printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n", clip_vcc);
98 		return;
99 	}
100 	netif_tx_lock_bh(entry->neigh->dev);	/* block clip_start_xmit() */
101 	entry->neigh->used = jiffies;
102 	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
103 		if (*walk == clip_vcc) {
104 			int error;
105 
106 			*walk = clip_vcc->next;	/* atomic */
107 			clip_vcc->entry = NULL;
108 			if (clip_vcc->xoff)
109 				netif_wake_queue(entry->neigh->dev);
110 			if (entry->vccs)
111 				goto out;
112 			entry->expires = jiffies - 1;
113 			/* force resolution or expiration */
114 			error = neigh_update(entry->neigh, NULL, NUD_NONE,
115 					     NEIGH_UPDATE_F_ADMIN);
116 			if (error)
117 				printk(KERN_CRIT "unlink_clip_vcc: "
118 				       "neigh_update failed with %d\n", error);
119 			goto out;
120 		}
121 	printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "
122 	       "0x%p)\n", entry, clip_vcc);
123       out:
124 	netif_tx_unlock_bh(entry->neigh->dev);
125 }
126 
127 /* The neighbour entry n->lock is held. */
128 static int neigh_check_cb(struct neighbour *n)
129 {
130 	struct atmarp_entry *entry = NEIGH2ENTRY(n);
131 	struct clip_vcc *cv;
132 
133 	for (cv = entry->vccs; cv; cv = cv->next) {
134 		unsigned long exp = cv->last_use + cv->idle_timeout;
135 
136 		if (cv->idle_timeout && time_after(jiffies, exp)) {
137 			DPRINTK("releasing vcc %p->%p of entry %p\n",
138 				cv, cv->vcc, entry);
139 			vcc_release_async(cv->vcc, -ETIMEDOUT);
140 		}
141 	}
142 
143 	if (entry->vccs || time_before(jiffies, entry->expires))
144 		return 0;
145 
146 	if (atomic_read(&n->refcnt) > 1) {
147 		struct sk_buff *skb;
148 
149 		DPRINTK("destruction postponed with ref %d\n",
150 			atomic_read(&n->refcnt));
151 
152 		while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
153 			dev_kfree_skb(skb);
154 
155 		return 0;
156 	}
157 
158 	DPRINTK("expired neigh %p\n", n);
159 	return 1;
160 }
161 
162 static void idle_timer_check(unsigned long dummy)
163 {
164 	write_lock(&clip_tbl.lock);
165 	__neigh_for_each_release(&clip_tbl, neigh_check_cb);
166 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
167 	write_unlock(&clip_tbl.lock);
168 }
169 
170 static int clip_arp_rcv(struct sk_buff *skb)
171 {
172 	struct atm_vcc *vcc;
173 
174 	DPRINTK("clip_arp_rcv\n");
175 	vcc = ATM_SKB(skb)->vcc;
176 	if (!vcc || !atm_charge(vcc, skb->truesize)) {
177 		dev_kfree_skb_any(skb);
178 		return 0;
179 	}
180 	DPRINTK("pushing to %p\n", vcc);
181 	DPRINTK("using %p\n", CLIP_VCC(vcc)->old_push);
182 	CLIP_VCC(vcc)->old_push(vcc, skb);
183 	return 0;
184 }
185 
186 static const unsigned char llc_oui[] = {
187 	0xaa,	/* DSAP: non-ISO */
188 	0xaa,	/* SSAP: non-ISO */
189 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
190 	0x00,	/* OUI: EtherType */
191 	0x00,
192 	0x00
193 };
194 
195 static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
196 {
197 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
198 
199 	DPRINTK("clip push\n");
200 	if (!skb) {
201 		DPRINTK("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 			PRIV(skb->dev)->stats.rx_packets++;
226 			PRIV(skb->dev)->stats.rx_bytes += skb->len;
227 			clip_arp_rcv(skb);
228 			return;
229 		}
230 	}
231 	clip_vcc->last_use = jiffies;
232 	PRIV(skb->dev)->stats.rx_packets++;
233 	PRIV(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 	DPRINTK("clip_pop(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 	DPRINTK("clip_neigh_solicit (neigh %p, skb %p)\n", neigh, skb);
267 	to_atmarpd(act_need, PRIV(neigh->dev)->number, NEIGH2ENTRY(neigh)->ip);
268 }
269 
270 static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
271 {
272 #ifndef CONFIG_ATM_CLIP_NO_ICMP
273 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
274 #endif
275 	kfree_skb(skb);
276 }
277 
278 static struct neigh_ops clip_neigh_ops = {
279 	.family =		AF_INET,
280 	.solicit =		clip_neigh_solicit,
281 	.error_report =		clip_neigh_error,
282 	.output =		dev_queue_xmit,
283 	.connected_output =	dev_queue_xmit,
284 	.hh_output =		dev_queue_xmit,
285 	.queue_xmit =		dev_queue_xmit,
286 };
287 
288 static int clip_constructor(struct neighbour *neigh)
289 {
290 	struct atmarp_entry *entry = NEIGH2ENTRY(neigh);
291 	struct net_device *dev = neigh->dev;
292 	struct in_device *in_dev;
293 	struct neigh_parms *parms;
294 
295 	DPRINTK("clip_constructor (neigh %p, entry %p)\n", neigh, entry);
296 	neigh->type = inet_addr_type(entry->ip);
297 	if (neigh->type != RTN_UNICAST)
298 		return -EINVAL;
299 
300 	rcu_read_lock();
301 	in_dev = __in_dev_get_rcu(dev);
302 	if (!in_dev) {
303 		rcu_read_unlock();
304 		return -EINVAL;
305 	}
306 
307 	parms = in_dev->arp_parms;
308 	__neigh_parms_put(neigh->parms);
309 	neigh->parms = neigh_parms_clone(parms);
310 	rcu_read_unlock();
311 
312 	neigh->ops = &clip_neigh_ops;
313 	neigh->output = neigh->nud_state & NUD_VALID ?
314 	    neigh->ops->connected_output : neigh->ops->output;
315 	entry->neigh = neigh;
316 	entry->vccs = NULL;
317 	entry->expires = jiffies - 1;
318 	return 0;
319 }
320 
321 static u32 clip_hash(const void *pkey, const struct net_device *dev)
322 {
323 	return jhash_2words(*(u32 *) pkey, dev->ifindex, clip_tbl.hash_rnd);
324 }
325 
326 static struct neigh_table clip_tbl = {
327 	.family 	= AF_INET,
328 	.entry_size 	= sizeof(struct neighbour)+sizeof(struct atmarp_entry),
329 	.key_len 	= 4,
330 	.hash 		= clip_hash,
331 	.constructor 	= clip_constructor,
332 	.id 		= "clip_arp_cache",
333 
334 	/* parameters are copied from ARP ... */
335 	.parms = {
336 		.tbl 			= &clip_tbl,
337 		.base_reachable_time 	= 30 * HZ,
338 		.retrans_time 		= 1 * HZ,
339 		.gc_staletime 		= 60 * HZ,
340 		.reachable_time 	= 30 * HZ,
341 		.delay_probe_time 	= 5 * HZ,
342 		.queue_len 		= 3,
343 		.ucast_probes 		= 3,
344 		.mcast_probes 		= 3,
345 		.anycast_delay 		= 1 * HZ,
346 		.proxy_delay 		= (8 * HZ) / 10,
347 		.proxy_qlen 		= 64,
348 		.locktime 		= 1 * HZ,
349 	},
350 	.gc_interval 	= 30 * HZ,
351 	.gc_thresh1 	= 128,
352 	.gc_thresh2 	= 512,
353 	.gc_thresh3 	= 1024,
354 };
355 
356 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
357 
358 /*
359  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
360  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
361  * don't increment the usage count. This is used to create entries in
362  * clip_setentry.
363  */
364 
365 static int clip_encap(struct atm_vcc *vcc, int mode)
366 {
367 	CLIP_VCC(vcc)->encap = mode;
368 	return 0;
369 }
370 
371 static int clip_start_xmit(struct sk_buff *skb, struct net_device *dev)
372 {
373 	struct clip_priv *clip_priv = PRIV(dev);
374 	struct atmarp_entry *entry;
375 	struct atm_vcc *vcc;
376 	int old;
377 	unsigned long flags;
378 
379 	DPRINTK("clip_start_xmit (skb %p)\n", skb);
380 	if (!skb->dst) {
381 		printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");
382 		dev_kfree_skb(skb);
383 		clip_priv->stats.tx_dropped++;
384 		return 0;
385 	}
386 	if (!skb->dst->neighbour) {
387 #if 0
388 		skb->dst->neighbour = clip_find_neighbour(skb->dst, 1);
389 		if (!skb->dst->neighbour) {
390 			dev_kfree_skb(skb);	/* lost that one */
391 			clip_priv->stats.tx_dropped++;
392 			return 0;
393 		}
394 #endif
395 		printk(KERN_ERR "clip_start_xmit: NO NEIGHBOUR !\n");
396 		dev_kfree_skb(skb);
397 		clip_priv->stats.tx_dropped++;
398 		return 0;
399 	}
400 	entry = NEIGH2ENTRY(skb->dst->neighbour);
401 	if (!entry->vccs) {
402 		if (time_after(jiffies, entry->expires)) {
403 			/* should be resolved */
404 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
405 			to_atmarpd(act_need, PRIV(dev)->number, entry->ip);
406 		}
407 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
408 			skb_queue_tail(&entry->neigh->arp_queue, skb);
409 		else {
410 			dev_kfree_skb(skb);
411 			clip_priv->stats.tx_dropped++;
412 		}
413 		return 0;
414 	}
415 	DPRINTK("neigh %p, vccs %p\n", entry, entry->vccs);
416 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
417 	DPRINTK("using neighbour %p, vcc %p\n", skb->dst->neighbour, vcc);
418 	if (entry->vccs->encap) {
419 		void *here;
420 
421 		here = skb_push(skb, RFC1483LLC_LEN);
422 		memcpy(here, llc_oui, sizeof(llc_oui));
423 		((__be16 *) here)[3] = skb->protocol;
424 	}
425 	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
426 	ATM_SKB(skb)->atm_options = vcc->atm_options;
427 	entry->vccs->last_use = jiffies;
428 	DPRINTK("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
429 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
430 	if (old) {
431 		printk(KERN_WARNING "clip_start_xmit: XOFF->XOFF transition\n");
432 		return 0;
433 	}
434 	clip_priv->stats.tx_packets++;
435 	clip_priv->stats.tx_bytes += skb->len;
436 	vcc->send(vcc, skb);
437 	if (atm_may_send(vcc, 0)) {
438 		entry->vccs->xoff = 0;
439 		return 0;
440 	}
441 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
442 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
443 	barrier();
444 	if (!entry->vccs->xoff)
445 		netif_start_queue(dev);
446 	/* Oh, we just raced with clip_pop. netif_start_queue should be
447 	   good enough, because nothing should really be asleep because
448 	   of the brief netif_stop_queue. If this isn't true or if it
449 	   changes, use netif_wake_queue instead. */
450 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
451 	return 0;
452 }
453 
454 static struct net_device_stats *clip_get_stats(struct net_device *dev)
455 {
456 	return &PRIV(dev)->stats;
457 }
458 
459 static int clip_mkip(struct atm_vcc *vcc, int timeout)
460 {
461 	struct clip_vcc *clip_vcc;
462 	struct sk_buff *skb;
463 	struct sk_buff_head *rq;
464 	unsigned long flags;
465 
466 	if (!vcc->push)
467 		return -EBADFD;
468 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
469 	if (!clip_vcc)
470 		return -ENOMEM;
471 	DPRINTK("mkip clip_vcc %p vcc %p\n", clip_vcc, vcc);
472 	clip_vcc->vcc = vcc;
473 	vcc->user_back = clip_vcc;
474 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
475 	clip_vcc->entry = NULL;
476 	clip_vcc->xoff = 0;
477 	clip_vcc->encap = 1;
478 	clip_vcc->last_use = jiffies;
479 	clip_vcc->idle_timeout = timeout * HZ;
480 	clip_vcc->old_push = vcc->push;
481 	clip_vcc->old_pop = vcc->pop;
482 	vcc->push = clip_push;
483 	vcc->pop = clip_pop;
484 
485 	rq = &sk_atm(vcc)->sk_receive_queue;
486 
487 	spin_lock_irqsave(&rq->lock, flags);
488 	if (skb_queue_empty(rq)) {
489 		skb = NULL;
490 	} else {
491 		/* NULL terminate the list.  */
492 		rq->prev->next = NULL;
493 		skb = rq->next;
494 	}
495 	rq->prev = rq->next = (struct sk_buff *)rq;
496 	rq->qlen = 0;
497 	spin_unlock_irqrestore(&rq->lock, flags);
498 
499 	/* re-process everything received between connection setup and MKIP */
500 	while (skb) {
501 		struct sk_buff *next = skb->next;
502 
503 		skb->next = skb->prev = NULL;
504 		if (!clip_devs) {
505 			atm_return(vcc, skb->truesize);
506 			kfree_skb(skb);
507 		} else {
508 			unsigned int len = skb->len;
509 
510 			skb_get(skb);
511 			clip_push(vcc, skb);
512 			PRIV(skb->dev)->stats.rx_packets--;
513 			PRIV(skb->dev)->stats.rx_bytes -= len;
514 			kfree_skb(skb);
515 		}
516 
517 		skb = next;
518 	}
519 	return 0;
520 }
521 
522 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
523 {
524 	struct neighbour *neigh;
525 	struct atmarp_entry *entry;
526 	int error;
527 	struct clip_vcc *clip_vcc;
528 	struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, .tos = 1}} };
529 	struct rtable *rt;
530 
531 	if (vcc->push != clip_push) {
532 		printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");
533 		return -EBADF;
534 	}
535 	clip_vcc = CLIP_VCC(vcc);
536 	if (!ip) {
537 		if (!clip_vcc->entry) {
538 			printk(KERN_ERR "hiding hidden ATMARP entry\n");
539 			return 0;
540 		}
541 		DPRINTK("setentry: remove\n");
542 		unlink_clip_vcc(clip_vcc);
543 		return 0;
544 	}
545 	error = ip_route_output_key(&rt, &fl);
546 	if (error)
547 		return error;
548 	neigh = __neigh_lookup(&clip_tbl, &ip, rt->u.dst.dev, 1);
549 	ip_rt_put(rt);
550 	if (!neigh)
551 		return -ENOMEM;
552 	entry = NEIGH2ENTRY(neigh);
553 	if (entry != clip_vcc->entry) {
554 		if (!clip_vcc->entry)
555 			DPRINTK("setentry: add\n");
556 		else {
557 			DPRINTK("setentry: update\n");
558 			unlink_clip_vcc(clip_vcc);
559 		}
560 		link_vcc(clip_vcc, entry);
561 	}
562 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
563 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
564 	neigh_release(neigh);
565 	return error;
566 }
567 
568 static void clip_setup(struct net_device *dev)
569 {
570 	dev->hard_start_xmit = clip_start_xmit;
571 	/* sg_xmit ... */
572 	dev->get_stats = clip_get_stats;
573 	dev->type = ARPHRD_ATM;
574 	dev->hard_header_len = RFC1483LLC_LEN;
575 	dev->mtu = RFC1626_MTU;
576 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
577 	/* When using a "real" qdisc, the qdisc determines the queue */
578 	/* length. tx_queue_len is only used for the default case, */
579 	/* without any more elaborate queuing. 100 is a reasonable */
580 	/* compromise between decent burst-tolerance and protection */
581 	/* against memory hogs. */
582 }
583 
584 static int clip_create(int number)
585 {
586 	struct net_device *dev;
587 	struct clip_priv *clip_priv;
588 	int error;
589 
590 	if (number != -1) {
591 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
592 			if (PRIV(dev)->number == number)
593 				return -EEXIST;
594 	} else {
595 		number = 0;
596 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
597 			if (PRIV(dev)->number >= number)
598 				number = PRIV(dev)->number + 1;
599 	}
600 	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
601 	if (!dev)
602 		return -ENOMEM;
603 	clip_priv = PRIV(dev);
604 	sprintf(dev->name, "atm%d", number);
605 	spin_lock_init(&clip_priv->xoff_lock);
606 	clip_priv->number = number;
607 	error = register_netdev(dev);
608 	if (error) {
609 		free_netdev(dev);
610 		return error;
611 	}
612 	clip_priv->next = clip_devs;
613 	clip_devs = dev;
614 	DPRINTK("registered (net:%s)\n", dev->name);
615 	return number;
616 }
617 
618 static int clip_device_event(struct notifier_block *this, unsigned long event,
619 			     void *arg)
620 {
621 	struct net_device *dev = arg;
622 
623 	if (event == NETDEV_UNREGISTER) {
624 		neigh_ifdown(&clip_tbl, dev);
625 		return NOTIFY_DONE;
626 	}
627 
628 	/* ignore non-CLIP devices */
629 	if (dev->type != ARPHRD_ATM || dev->hard_start_xmit != clip_start_xmit)
630 		return NOTIFY_DONE;
631 
632 	switch (event) {
633 	case NETDEV_UP:
634 		DPRINTK("clip_device_event NETDEV_UP\n");
635 		to_atmarpd(act_up, PRIV(dev)->number, 0);
636 		break;
637 	case NETDEV_GOING_DOWN:
638 		DPRINTK("clip_device_event NETDEV_DOWN\n");
639 		to_atmarpd(act_down, PRIV(dev)->number, 0);
640 		break;
641 	case NETDEV_CHANGE:
642 	case NETDEV_CHANGEMTU:
643 		DPRINTK("clip_device_event NETDEV_CHANGE*\n");
644 		to_atmarpd(act_change, PRIV(dev)->number, 0);
645 		break;
646 	}
647 	return NOTIFY_DONE;
648 }
649 
650 static int clip_inet_event(struct notifier_block *this, unsigned long event,
651 			   void *ifa)
652 {
653 	struct in_device *in_dev;
654 
655 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
656 	if (!in_dev || !in_dev->dev) {
657 		printk(KERN_WARNING "clip_inet_event: no device\n");
658 		return NOTIFY_DONE;
659 	}
660 	/*
661 	 * Transitions are of the down-change-up type, so it's sufficient to
662 	 * handle the change on up.
663 	 */
664 	if (event != NETDEV_UP)
665 		return NOTIFY_DONE;
666 	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
667 }
668 
669 
670 static struct notifier_block clip_dev_notifier = {
671 	.notifier_call = clip_device_event,
672 };
673 
674 
675 
676 static struct notifier_block clip_inet_notifier = {
677 	.notifier_call = clip_inet_event,
678 };
679 
680 
681 
682 static void atmarpd_close(struct atm_vcc *vcc)
683 {
684 	DPRINTK("atmarpd_close\n");
685 
686 	rtnl_lock();
687 	atmarpd = NULL;
688 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
689 	rtnl_unlock();
690 
691 	DPRINTK("(done)\n");
692 	module_put(THIS_MODULE);
693 }
694 
695 
696 static struct atmdev_ops atmarpd_dev_ops = {
697 	.close = atmarpd_close
698 };
699 
700 
701 static struct atm_dev atmarpd_dev = {
702 	.ops =			&atmarpd_dev_ops,
703 	.type =			"arpd",
704 	.number = 		999,
705 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
706 };
707 
708 
709 static int atm_init_atmarp(struct atm_vcc *vcc)
710 {
711 	rtnl_lock();
712 	if (atmarpd) {
713 		rtnl_unlock();
714 		return -EADDRINUSE;
715 	}
716 
717 	mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
718 
719 	atmarpd = vcc;
720 	set_bit(ATM_VF_META,&vcc->flags);
721 	set_bit(ATM_VF_READY,&vcc->flags);
722 	    /* allow replies and avoid getting closed if signaling dies */
723 	vcc->dev = &atmarpd_dev;
724 	vcc_insert_socket(sk_atm(vcc));
725 	vcc->push = NULL;
726 	vcc->pop = NULL; /* crash */
727 	vcc->push_oam = NULL; /* crash */
728 	rtnl_unlock();
729 	return 0;
730 }
731 
732 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
733 {
734 	struct atm_vcc *vcc = ATM_SD(sock);
735 	int err = 0;
736 
737 	switch (cmd) {
738 	case SIOCMKCLIP:
739 	case ATMARPD_CTRL:
740 	case ATMARP_MKIP:
741 	case ATMARP_SETENTRY:
742 	case ATMARP_ENCAP:
743 		if (!capable(CAP_NET_ADMIN))
744 			return -EPERM;
745 		break;
746 	default:
747 		return -ENOIOCTLCMD;
748 	}
749 
750 	switch (cmd) {
751 	case SIOCMKCLIP:
752 		err = clip_create(arg);
753 		break;
754 	case ATMARPD_CTRL:
755 		err = atm_init_atmarp(vcc);
756 		if (!err) {
757 			sock->state = SS_CONNECTED;
758 			__module_get(THIS_MODULE);
759 		}
760 		break;
761 	case ATMARP_MKIP:
762 		err = clip_mkip(vcc, arg);
763 		break;
764 	case ATMARP_SETENTRY:
765 		err = clip_setentry(vcc, (__force __be32)arg);
766 		break;
767 	case ATMARP_ENCAP:
768 		err = clip_encap(vcc, arg);
769 		break;
770 	}
771 	return err;
772 }
773 
774 static struct atm_ioctl clip_ioctl_ops = {
775 	.owner = THIS_MODULE,
776 	.ioctl = clip_ioctl,
777 };
778 
779 #ifdef CONFIG_PROC_FS
780 
781 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
782 {
783 	static int code[] = { 1, 2, 10, 6, 1, 0 };
784 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
785 
786 	if (*addr->sas_addr.pub) {
787 		seq_printf(seq, "%s", addr->sas_addr.pub);
788 		if (*addr->sas_addr.prv)
789 			seq_putc(seq, '+');
790 	} else if (!*addr->sas_addr.prv) {
791 		seq_printf(seq, "%s", "(none)");
792 		return;
793 	}
794 	if (*addr->sas_addr.prv) {
795 		unsigned char *prv = addr->sas_addr.prv;
796 		int *fields;
797 		int i, j;
798 
799 		fields = *prv == ATM_AFI_E164 ? e164 : code;
800 		for (i = 0; fields[i]; i++) {
801 			for (j = fields[i]; j; j--)
802 				seq_printf(seq, "%02X", *prv++);
803 			if (fields[i + 1])
804 				seq_putc(seq, '.');
805 		}
806 	}
807 }
808 
809 /* This means the neighbour entry has no attached VCC objects. */
810 #define SEQ_NO_VCC_TOKEN	((void *) 2)
811 
812 static void atmarp_info(struct seq_file *seq, struct net_device *dev,
813 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
814 {
815 	unsigned long exp;
816 	char buf[17];
817 	int svc, llc, off;
818 
819 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
820 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
821 
822 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
823 
824 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
825 		exp = entry->neigh->used;
826 	else
827 		exp = clip_vcc->last_use;
828 
829 	exp = (jiffies - exp) / HZ;
830 
831 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
832 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
833 
834 	off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d",
835 			NIPQUAD(entry->ip));
836 	while (off < 16)
837 		buf[off++] = ' ';
838 	buf[off] = '\0';
839 	seq_printf(seq, "%s", buf);
840 
841 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
842 		if (time_before(jiffies, entry->expires))
843 			seq_printf(seq, "(resolving)\n");
844 		else
845 			seq_printf(seq, "(expired, ref %d)\n",
846 				   atomic_read(&entry->neigh->refcnt));
847 	} else if (!svc) {
848 		seq_printf(seq, "%d.%d.%d\n",
849 			   clip_vcc->vcc->dev->number,
850 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
851 	} else {
852 		svc_addr(seq, &clip_vcc->vcc->remote);
853 		seq_putc(seq, '\n');
854 	}
855 }
856 
857 struct clip_seq_state {
858 	/* This member must be first. */
859 	struct neigh_seq_state ns;
860 
861 	/* Local to clip specific iteration. */
862 	struct clip_vcc *vcc;
863 };
864 
865 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
866 					  struct clip_vcc *curr)
867 {
868 	if (!curr) {
869 		curr = e->vccs;
870 		if (!curr)
871 			return SEQ_NO_VCC_TOKEN;
872 		return curr;
873 	}
874 	if (curr == SEQ_NO_VCC_TOKEN)
875 		return NULL;
876 
877 	curr = curr->next;
878 
879 	return curr;
880 }
881 
882 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
883 			       struct atmarp_entry *e, loff_t * pos)
884 {
885 	struct clip_vcc *vcc = state->vcc;
886 
887 	vcc = clip_seq_next_vcc(e, vcc);
888 	if (vcc && pos != NULL) {
889 		while (*pos) {
890 			vcc = clip_seq_next_vcc(e, vcc);
891 			if (!vcc)
892 				break;
893 			--(*pos);
894 		}
895 	}
896 	state->vcc = vcc;
897 
898 	return vcc;
899 }
900 
901 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
902 			       struct neighbour *n, loff_t * pos)
903 {
904 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
905 
906 	return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
907 }
908 
909 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
910 {
911 	return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
912 }
913 
914 static int clip_seq_show(struct seq_file *seq, void *v)
915 {
916 	static char atm_arp_banner[] =
917 	    "IPitf TypeEncp Idle IP address      ATM address\n";
918 
919 	if (v == SEQ_START_TOKEN) {
920 		seq_puts(seq, atm_arp_banner);
921 	} else {
922 		struct clip_seq_state *state = seq->private;
923 		struct neighbour *n = v;
924 		struct clip_vcc *vcc = state->vcc;
925 
926 		atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);
927 	}
928 	return 0;
929 }
930 
931 static struct seq_operations arp_seq_ops = {
932 	.start	= clip_seq_start,
933 	.next	= neigh_seq_next,
934 	.stop	= neigh_seq_stop,
935 	.show	= clip_seq_show,
936 };
937 
938 static int arp_seq_open(struct inode *inode, struct file *file)
939 {
940 	struct clip_seq_state *state;
941 	struct seq_file *seq;
942 	int rc = -EAGAIN;
943 
944 	state = kzalloc(sizeof(*state), GFP_KERNEL);
945 	if (!state) {
946 		rc = -ENOMEM;
947 		goto out_kfree;
948 	}
949 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
950 
951 	rc = seq_open(file, &arp_seq_ops);
952 	if (rc)
953 		goto out_kfree;
954 
955 	seq = file->private_data;
956 	seq->private = state;
957 out:
958 	return rc;
959 
960 out_kfree:
961 	kfree(state);
962 	goto out;
963 }
964 
965 static const struct file_operations arp_seq_fops = {
966 	.open		= arp_seq_open,
967 	.read		= seq_read,
968 	.llseek		= seq_lseek,
969 	.release	= seq_release_private,
970 	.owner		= THIS_MODULE
971 };
972 #endif
973 
974 static int __init atm_clip_init(void)
975 {
976 	neigh_table_init_no_netlink(&clip_tbl);
977 
978 	clip_tbl_hook = &clip_tbl;
979 	register_atm_ioctl(&clip_ioctl_ops);
980 	register_netdevice_notifier(&clip_dev_notifier);
981 	register_inetaddr_notifier(&clip_inet_notifier);
982 
983 	setup_timer(&idle_timer, idle_timer_check, 0);
984 
985 #ifdef CONFIG_PROC_FS
986 	{
987 		struct proc_dir_entry *p;
988 
989 		p = create_proc_entry("arp", S_IRUGO, atm_proc_root);
990 		if (p)
991 			p->proc_fops = &arp_seq_fops;
992 	}
993 #endif
994 
995 	return 0;
996 }
997 
998 static void __exit atm_clip_exit(void)
999 {
1000 	struct net_device *dev, *next;
1001 
1002 	remove_proc_entry("arp", atm_proc_root);
1003 
1004 	unregister_inetaddr_notifier(&clip_inet_notifier);
1005 	unregister_netdevice_notifier(&clip_dev_notifier);
1006 
1007 	deregister_atm_ioctl(&clip_ioctl_ops);
1008 
1009 	/* First, stop the idle timer, so it stops banging
1010 	 * on the table.
1011 	 */
1012 	del_timer_sync(&idle_timer);
1013 
1014 	/* Next, purge the table, so that the device
1015 	 * unregister loop below does not hang due to
1016 	 * device references remaining in the table.
1017 	 */
1018 	neigh_ifdown(&clip_tbl, NULL);
1019 
1020 	dev = clip_devs;
1021 	while (dev) {
1022 		next = PRIV(dev)->next;
1023 		unregister_netdev(dev);
1024 		free_netdev(dev);
1025 		dev = next;
1026 	}
1027 
1028 	/* Now it is safe to fully shutdown whole table. */
1029 	neigh_table_clear(&clip_tbl);
1030 
1031 	clip_tbl_hook = NULL;
1032 }
1033 
1034 module_init(atm_clip_init);
1035 module_exit(atm_clip_exit);
1036 MODULE_AUTHOR("Werner Almesberger");
1037 MODULE_DESCRIPTION("Classical/IP over ATM interface");
1038 MODULE_LICENSE("GPL");
1039