xref: /openbmc/linux/net/atm/clip.c (revision 9d749629)
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 <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 timer_list idle_timer;
49 static const struct neigh_ops clip_neigh_ops;
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 = neighbour_priv(n);
123 	struct clip_vcc *cv;
124 
125 	if (n->ops != &clip_neigh_ops)
126 		return 0;
127 	for (cv = entry->vccs; cv; cv = cv->next) {
128 		unsigned long exp = cv->last_use + cv->idle_timeout;
129 
130 		if (cv->idle_timeout && time_after(jiffies, exp)) {
131 			pr_debug("releasing vcc %p->%p of entry %p\n",
132 				 cv, cv->vcc, entry);
133 			vcc_release_async(cv->vcc, -ETIMEDOUT);
134 		}
135 	}
136 
137 	if (entry->vccs || time_before(jiffies, entry->expires))
138 		return 0;
139 
140 	if (atomic_read(&n->refcnt) > 1) {
141 		struct sk_buff *skb;
142 
143 		pr_debug("destruction postponed with ref %d\n",
144 			 atomic_read(&n->refcnt));
145 
146 		while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
147 			dev_kfree_skb(skb);
148 
149 		return 0;
150 	}
151 
152 	pr_debug("expired neigh %p\n", n);
153 	return 1;
154 }
155 
156 static void idle_timer_check(unsigned long dummy)
157 {
158 	write_lock(&arp_tbl.lock);
159 	__neigh_for_each_release(&arp_tbl, neigh_check_cb);
160 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
161 	write_unlock(&arp_tbl.lock);
162 }
163 
164 static int clip_arp_rcv(struct sk_buff *skb)
165 {
166 	struct atm_vcc *vcc;
167 
168 	pr_debug("\n");
169 	vcc = ATM_SKB(skb)->vcc;
170 	if (!vcc || !atm_charge(vcc, skb->truesize)) {
171 		dev_kfree_skb_any(skb);
172 		return 0;
173 	}
174 	pr_debug("pushing to %p\n", vcc);
175 	pr_debug("using %p\n", CLIP_VCC(vcc)->old_push);
176 	CLIP_VCC(vcc)->old_push(vcc, skb);
177 	return 0;
178 }
179 
180 static const unsigned char llc_oui[] = {
181 	0xaa,	/* DSAP: non-ISO */
182 	0xaa,	/* SSAP: non-ISO */
183 	0x03,	/* Ctrl: Unnumbered Information Command PDU */
184 	0x00,	/* OUI: EtherType */
185 	0x00,
186 	0x00
187 };
188 
189 static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
190 {
191 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
192 
193 	pr_debug("\n");
194 
195 	if (!clip_devs) {
196 		atm_return(vcc, skb->truesize);
197 		kfree_skb(skb);
198 		return;
199 	}
200 
201 	if (!skb) {
202 		pr_debug("removing VCC %p\n", clip_vcc);
203 		if (clip_vcc->entry)
204 			unlink_clip_vcc(clip_vcc);
205 		clip_vcc->old_push(vcc, NULL);	/* pass on the bad news */
206 		kfree(clip_vcc);
207 		return;
208 	}
209 	atm_return(vcc, skb->truesize);
210 	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
211 	/* clip_vcc->entry == NULL if we don't have an IP address yet */
212 	if (!skb->dev) {
213 		dev_kfree_skb_any(skb);
214 		return;
215 	}
216 	ATM_SKB(skb)->vcc = vcc;
217 	skb_reset_mac_header(skb);
218 	if (!clip_vcc->encap ||
219 	    skb->len < RFC1483LLC_LEN ||
220 	    memcmp(skb->data, llc_oui, sizeof(llc_oui)))
221 		skb->protocol = htons(ETH_P_IP);
222 	else {
223 		skb->protocol = ((__be16 *)skb->data)[3];
224 		skb_pull(skb, RFC1483LLC_LEN);
225 		if (skb->protocol == htons(ETH_P_ARP)) {
226 			skb->dev->stats.rx_packets++;
227 			skb->dev->stats.rx_bytes += skb->len;
228 			clip_arp_rcv(skb);
229 			return;
230 		}
231 	}
232 	clip_vcc->last_use = jiffies;
233 	skb->dev->stats.rx_packets++;
234 	skb->dev->stats.rx_bytes += skb->len;
235 	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
236 	netif_rx(skb);
237 }
238 
239 /*
240  * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
241  * clip_pop is atomic with respect to the critical section in clip_start_xmit.
242  */
243 
244 static void clip_pop(struct atm_vcc *vcc, struct sk_buff *skb)
245 {
246 	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
247 	struct net_device *dev = skb->dev;
248 	int old;
249 	unsigned long flags;
250 
251 	pr_debug("(vcc %p)\n", vcc);
252 	clip_vcc->old_pop(vcc, skb);
253 	/* skb->dev == NULL in outbound ARP packets */
254 	if (!dev)
255 		return;
256 	spin_lock_irqsave(&PRIV(dev)->xoff_lock, flags);
257 	if (atm_may_send(vcc, 0)) {
258 		old = xchg(&clip_vcc->xoff, 0);
259 		if (old)
260 			netif_wake_queue(dev);
261 	}
262 	spin_unlock_irqrestore(&PRIV(dev)->xoff_lock, flags);
263 }
264 
265 static void clip_neigh_solicit(struct neighbour *neigh, struct sk_buff *skb)
266 {
267 	__be32 *ip = (__be32 *) neigh->primary_key;
268 
269 	pr_debug("(neigh %p, skb %p)\n", neigh, skb);
270 	to_atmarpd(act_need, PRIV(neigh->dev)->number, *ip);
271 }
272 
273 static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
274 {
275 #ifndef CONFIG_ATM_CLIP_NO_ICMP
276 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
277 #endif
278 	kfree_skb(skb);
279 }
280 
281 static const struct neigh_ops clip_neigh_ops = {
282 	.family =		AF_INET,
283 	.solicit =		clip_neigh_solicit,
284 	.error_report =		clip_neigh_error,
285 	.output =		neigh_direct_output,
286 	.connected_output =	neigh_direct_output,
287 };
288 
289 static int clip_constructor(struct neighbour *neigh)
290 {
291 	struct atmarp_entry *entry = neighbour_priv(neigh);
292 
293 	if (neigh->tbl->family != AF_INET)
294 		return -EINVAL;
295 
296 	if (neigh->type != RTN_UNICAST)
297 		return -EINVAL;
298 
299 	neigh->nud_state = NUD_NONE;
300 	neigh->ops = &clip_neigh_ops;
301 	neigh->output = neigh->ops->output;
302 	entry->neigh = neigh;
303 	entry->vccs = NULL;
304 	entry->expires = jiffies - 1;
305 
306 	return 0;
307 }
308 
309 /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
310 
311 /*
312  * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
313  * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
314  * don't increment the usage count. This is used to create entries in
315  * clip_setentry.
316  */
317 
318 static int clip_encap(struct atm_vcc *vcc, int mode)
319 {
320 	CLIP_VCC(vcc)->encap = mode;
321 	return 0;
322 }
323 
324 static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
325 				   struct net_device *dev)
326 {
327 	struct clip_priv *clip_priv = PRIV(dev);
328 	struct dst_entry *dst = skb_dst(skb);
329 	struct atmarp_entry *entry;
330 	struct neighbour *n;
331 	struct atm_vcc *vcc;
332 	struct rtable *rt;
333 	__be32 *daddr;
334 	int old;
335 	unsigned long flags;
336 
337 	pr_debug("(skb %p)\n", skb);
338 	if (!dst) {
339 		pr_err("skb_dst(skb) == NULL\n");
340 		dev_kfree_skb(skb);
341 		dev->stats.tx_dropped++;
342 		return NETDEV_TX_OK;
343 	}
344 	rt = (struct rtable *) dst;
345 	if (rt->rt_gateway)
346 		daddr = &rt->rt_gateway;
347 	else
348 		daddr = &ip_hdr(skb)->daddr;
349 	n = dst_neigh_lookup(dst, daddr);
350 	if (!n) {
351 		pr_err("NO NEIGHBOUR !\n");
352 		dev_kfree_skb(skb);
353 		dev->stats.tx_dropped++;
354 		return NETDEV_TX_OK;
355 	}
356 	entry = neighbour_priv(n);
357 	if (!entry->vccs) {
358 		if (time_after(jiffies, entry->expires)) {
359 			/* should be resolved */
360 			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
361 			to_atmarpd(act_need, PRIV(dev)->number, *((__be32 *)n->primary_key));
362 		}
363 		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
364 			skb_queue_tail(&entry->neigh->arp_queue, skb);
365 		else {
366 			dev_kfree_skb(skb);
367 			dev->stats.tx_dropped++;
368 		}
369 		goto out_release_neigh;
370 	}
371 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
372 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
373 	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
374 	if (entry->vccs->encap) {
375 		void *here;
376 
377 		here = skb_push(skb, RFC1483LLC_LEN);
378 		memcpy(here, llc_oui, sizeof(llc_oui));
379 		((__be16 *) here)[3] = skb->protocol;
380 	}
381 	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
382 	ATM_SKB(skb)->atm_options = vcc->atm_options;
383 	entry->vccs->last_use = jiffies;
384 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
385 	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
386 	if (old) {
387 		pr_warning("XOFF->XOFF transition\n");
388 		goto out_release_neigh;
389 	}
390 	dev->stats.tx_packets++;
391 	dev->stats.tx_bytes += skb->len;
392 	vcc->send(vcc, skb);
393 	if (atm_may_send(vcc, 0)) {
394 		entry->vccs->xoff = 0;
395 		goto out_release_neigh;
396 	}
397 	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
398 	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
399 	barrier();
400 	if (!entry->vccs->xoff)
401 		netif_start_queue(dev);
402 	/* Oh, we just raced with clip_pop. netif_start_queue should be
403 	   good enough, because nothing should really be asleep because
404 	   of the brief netif_stop_queue. If this isn't true or if it
405 	   changes, use netif_wake_queue instead. */
406 	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
407 out_release_neigh:
408 	neigh_release(n);
409 	return NETDEV_TX_OK;
410 }
411 
412 static int clip_mkip(struct atm_vcc *vcc, int timeout)
413 {
414 	struct clip_vcc *clip_vcc;
415 
416 	if (!vcc->push)
417 		return -EBADFD;
418 	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
419 	if (!clip_vcc)
420 		return -ENOMEM;
421 	pr_debug("%p vcc %p\n", clip_vcc, vcc);
422 	clip_vcc->vcc = vcc;
423 	vcc->user_back = clip_vcc;
424 	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
425 	clip_vcc->entry = NULL;
426 	clip_vcc->xoff = 0;
427 	clip_vcc->encap = 1;
428 	clip_vcc->last_use = jiffies;
429 	clip_vcc->idle_timeout = timeout * HZ;
430 	clip_vcc->old_push = vcc->push;
431 	clip_vcc->old_pop = vcc->pop;
432 	vcc->push = clip_push;
433 	vcc->pop = clip_pop;
434 
435 	/* re-process everything received between connection setup and MKIP */
436 	vcc_process_recv_queue(vcc);
437 
438 	return 0;
439 }
440 
441 static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
442 {
443 	struct neighbour *neigh;
444 	struct atmarp_entry *entry;
445 	int error;
446 	struct clip_vcc *clip_vcc;
447 	struct rtable *rt;
448 
449 	if (vcc->push != clip_push) {
450 		pr_warning("non-CLIP VCC\n");
451 		return -EBADF;
452 	}
453 	clip_vcc = CLIP_VCC(vcc);
454 	if (!ip) {
455 		if (!clip_vcc->entry) {
456 			pr_err("hiding hidden ATMARP entry\n");
457 			return 0;
458 		}
459 		pr_debug("remove\n");
460 		unlink_clip_vcc(clip_vcc);
461 		return 0;
462 	}
463 	rt = ip_route_output(&init_net, ip, 0, 1, 0);
464 	if (IS_ERR(rt))
465 		return PTR_ERR(rt);
466 	neigh = __neigh_lookup(&arp_tbl, &ip, rt->dst.dev, 1);
467 	ip_rt_put(rt);
468 	if (!neigh)
469 		return -ENOMEM;
470 	entry = neighbour_priv(neigh);
471 	if (entry != clip_vcc->entry) {
472 		if (!clip_vcc->entry)
473 			pr_debug("add\n");
474 		else {
475 			pr_debug("update\n");
476 			unlink_clip_vcc(clip_vcc);
477 		}
478 		link_vcc(clip_vcc, entry);
479 	}
480 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
481 			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
482 	neigh_release(neigh);
483 	return error;
484 }
485 
486 static const struct net_device_ops clip_netdev_ops = {
487 	.ndo_start_xmit		= clip_start_xmit,
488 	.ndo_neigh_construct	= clip_constructor,
489 };
490 
491 static void clip_setup(struct net_device *dev)
492 {
493 	dev->netdev_ops = &clip_netdev_ops;
494 	dev->type = ARPHRD_ATM;
495 	dev->neigh_priv_len = sizeof(struct atmarp_entry);
496 	dev->hard_header_len = RFC1483LLC_LEN;
497 	dev->mtu = RFC1626_MTU;
498 	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
499 	/* When using a "real" qdisc, the qdisc determines the queue */
500 	/* length. tx_queue_len is only used for the default case, */
501 	/* without any more elaborate queuing. 100 is a reasonable */
502 	/* compromise between decent burst-tolerance and protection */
503 	/* against memory hogs. */
504 	dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
505 }
506 
507 static int clip_create(int number)
508 {
509 	struct net_device *dev;
510 	struct clip_priv *clip_priv;
511 	int error;
512 
513 	if (number != -1) {
514 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
515 			if (PRIV(dev)->number == number)
516 				return -EEXIST;
517 	} else {
518 		number = 0;
519 		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
520 			if (PRIV(dev)->number >= number)
521 				number = PRIV(dev)->number + 1;
522 	}
523 	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
524 	if (!dev)
525 		return -ENOMEM;
526 	clip_priv = PRIV(dev);
527 	sprintf(dev->name, "atm%d", number);
528 	spin_lock_init(&clip_priv->xoff_lock);
529 	clip_priv->number = number;
530 	error = register_netdev(dev);
531 	if (error) {
532 		free_netdev(dev);
533 		return error;
534 	}
535 	clip_priv->next = clip_devs;
536 	clip_devs = dev;
537 	pr_debug("registered (net:%s)\n", dev->name);
538 	return number;
539 }
540 
541 static int clip_device_event(struct notifier_block *this, unsigned long event,
542 			     void *arg)
543 {
544 	struct net_device *dev = arg;
545 
546 	if (!net_eq(dev_net(dev), &init_net))
547 		return NOTIFY_DONE;
548 
549 	if (event == NETDEV_UNREGISTER)
550 		return NOTIFY_DONE;
551 
552 	/* ignore non-CLIP devices */
553 	if (dev->type != ARPHRD_ATM || dev->netdev_ops != &clip_netdev_ops)
554 		return NOTIFY_DONE;
555 
556 	switch (event) {
557 	case NETDEV_UP:
558 		pr_debug("NETDEV_UP\n");
559 		to_atmarpd(act_up, PRIV(dev)->number, 0);
560 		break;
561 	case NETDEV_GOING_DOWN:
562 		pr_debug("NETDEV_DOWN\n");
563 		to_atmarpd(act_down, PRIV(dev)->number, 0);
564 		break;
565 	case NETDEV_CHANGE:
566 	case NETDEV_CHANGEMTU:
567 		pr_debug("NETDEV_CHANGE*\n");
568 		to_atmarpd(act_change, PRIV(dev)->number, 0);
569 		break;
570 	}
571 	return NOTIFY_DONE;
572 }
573 
574 static int clip_inet_event(struct notifier_block *this, unsigned long event,
575 			   void *ifa)
576 {
577 	struct in_device *in_dev;
578 
579 	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
580 	/*
581 	 * Transitions are of the down-change-up type, so it's sufficient to
582 	 * handle the change on up.
583 	 */
584 	if (event != NETDEV_UP)
585 		return NOTIFY_DONE;
586 	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
587 }
588 
589 static struct notifier_block clip_dev_notifier = {
590 	.notifier_call = clip_device_event,
591 };
592 
593 
594 
595 static struct notifier_block clip_inet_notifier = {
596 	.notifier_call = clip_inet_event,
597 };
598 
599 
600 
601 static void atmarpd_close(struct atm_vcc *vcc)
602 {
603 	pr_debug("\n");
604 
605 	rtnl_lock();
606 	atmarpd = NULL;
607 	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
608 	rtnl_unlock();
609 
610 	pr_debug("(done)\n");
611 	module_put(THIS_MODULE);
612 }
613 
614 static struct atmdev_ops atmarpd_dev_ops = {
615 	.close = atmarpd_close
616 };
617 
618 
619 static struct atm_dev atmarpd_dev = {
620 	.ops =			&atmarpd_dev_ops,
621 	.type =			"arpd",
622 	.number = 		999,
623 	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
624 };
625 
626 
627 static int atm_init_atmarp(struct atm_vcc *vcc)
628 {
629 	rtnl_lock();
630 	if (atmarpd) {
631 		rtnl_unlock();
632 		return -EADDRINUSE;
633 	}
634 
635 	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
636 
637 	atmarpd = vcc;
638 	set_bit(ATM_VF_META, &vcc->flags);
639 	set_bit(ATM_VF_READY, &vcc->flags);
640 	    /* allow replies and avoid getting closed if signaling dies */
641 	vcc->dev = &atmarpd_dev;
642 	vcc_insert_socket(sk_atm(vcc));
643 	vcc->push = NULL;
644 	vcc->pop = NULL; /* crash */
645 	vcc->push_oam = NULL; /* crash */
646 	rtnl_unlock();
647 	return 0;
648 }
649 
650 static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
651 {
652 	struct atm_vcc *vcc = ATM_SD(sock);
653 	int err = 0;
654 
655 	switch (cmd) {
656 	case SIOCMKCLIP:
657 	case ATMARPD_CTRL:
658 	case ATMARP_MKIP:
659 	case ATMARP_SETENTRY:
660 	case ATMARP_ENCAP:
661 		if (!capable(CAP_NET_ADMIN))
662 			return -EPERM;
663 		break;
664 	default:
665 		return -ENOIOCTLCMD;
666 	}
667 
668 	switch (cmd) {
669 	case SIOCMKCLIP:
670 		err = clip_create(arg);
671 		break;
672 	case ATMARPD_CTRL:
673 		err = atm_init_atmarp(vcc);
674 		if (!err) {
675 			sock->state = SS_CONNECTED;
676 			__module_get(THIS_MODULE);
677 		}
678 		break;
679 	case ATMARP_MKIP:
680 		err = clip_mkip(vcc, arg);
681 		break;
682 	case ATMARP_SETENTRY:
683 		err = clip_setentry(vcc, (__force __be32)arg);
684 		break;
685 	case ATMARP_ENCAP:
686 		err = clip_encap(vcc, arg);
687 		break;
688 	}
689 	return err;
690 }
691 
692 static struct atm_ioctl clip_ioctl_ops = {
693 	.owner = THIS_MODULE,
694 	.ioctl = clip_ioctl,
695 };
696 
697 #ifdef CONFIG_PROC_FS
698 
699 static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
700 {
701 	static int code[] = { 1, 2, 10, 6, 1, 0 };
702 	static int e164[] = { 1, 8, 4, 6, 1, 0 };
703 
704 	if (*addr->sas_addr.pub) {
705 		seq_printf(seq, "%s", addr->sas_addr.pub);
706 		if (*addr->sas_addr.prv)
707 			seq_putc(seq, '+');
708 	} else if (!*addr->sas_addr.prv) {
709 		seq_printf(seq, "%s", "(none)");
710 		return;
711 	}
712 	if (*addr->sas_addr.prv) {
713 		unsigned char *prv = addr->sas_addr.prv;
714 		int *fields;
715 		int i, j;
716 
717 		fields = *prv == ATM_AFI_E164 ? e164 : code;
718 		for (i = 0; fields[i]; i++) {
719 			for (j = fields[i]; j; j--)
720 				seq_printf(seq, "%02X", *prv++);
721 			if (fields[i + 1])
722 				seq_putc(seq, '.');
723 		}
724 	}
725 }
726 
727 /* This means the neighbour entry has no attached VCC objects. */
728 #define SEQ_NO_VCC_TOKEN	((void *) 2)
729 
730 static void atmarp_info(struct seq_file *seq, struct neighbour *n,
731 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
732 {
733 	struct net_device *dev = n->dev;
734 	unsigned long exp;
735 	char buf[17];
736 	int svc, llc, off;
737 
738 	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
739 	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
740 
741 	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
742 
743 	if (clip_vcc == SEQ_NO_VCC_TOKEN)
744 		exp = entry->neigh->used;
745 	else
746 		exp = clip_vcc->last_use;
747 
748 	exp = (jiffies - exp) / HZ;
749 
750 	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
751 		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
752 
753 	off = scnprintf(buf, sizeof(buf) - 1, "%pI4", n->primary_key);
754 	while (off < 16)
755 		buf[off++] = ' ';
756 	buf[off] = '\0';
757 	seq_printf(seq, "%s", buf);
758 
759 	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
760 		if (time_before(jiffies, entry->expires))
761 			seq_printf(seq, "(resolving)\n");
762 		else
763 			seq_printf(seq, "(expired, ref %d)\n",
764 				   atomic_read(&entry->neigh->refcnt));
765 	} else if (!svc) {
766 		seq_printf(seq, "%d.%d.%d\n",
767 			   clip_vcc->vcc->dev->number,
768 			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
769 	} else {
770 		svc_addr(seq, &clip_vcc->vcc->remote);
771 		seq_putc(seq, '\n');
772 	}
773 }
774 
775 struct clip_seq_state {
776 	/* This member must be first. */
777 	struct neigh_seq_state ns;
778 
779 	/* Local to clip specific iteration. */
780 	struct clip_vcc *vcc;
781 };
782 
783 static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
784 					  struct clip_vcc *curr)
785 {
786 	if (!curr) {
787 		curr = e->vccs;
788 		if (!curr)
789 			return SEQ_NO_VCC_TOKEN;
790 		return curr;
791 	}
792 	if (curr == SEQ_NO_VCC_TOKEN)
793 		return NULL;
794 
795 	curr = curr->next;
796 
797 	return curr;
798 }
799 
800 static void *clip_seq_vcc_walk(struct clip_seq_state *state,
801 			       struct atmarp_entry *e, loff_t * pos)
802 {
803 	struct clip_vcc *vcc = state->vcc;
804 
805 	vcc = clip_seq_next_vcc(e, vcc);
806 	if (vcc && pos != NULL) {
807 		while (*pos) {
808 			vcc = clip_seq_next_vcc(e, vcc);
809 			if (!vcc)
810 				break;
811 			--(*pos);
812 		}
813 	}
814 	state->vcc = vcc;
815 
816 	return vcc;
817 }
818 
819 static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
820 			       struct neighbour *n, loff_t * pos)
821 {
822 	struct clip_seq_state *state = (struct clip_seq_state *)_state;
823 
824 	if (n->dev->type != ARPHRD_ATM)
825 		return NULL;
826 
827 	return clip_seq_vcc_walk(state, neighbour_priv(n), pos);
828 }
829 
830 static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
831 {
832 	struct clip_seq_state *state = seq->private;
833 	state->ns.neigh_sub_iter = clip_seq_sub_iter;
834 	return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_NEIGH_ONLY);
835 }
836 
837 static int clip_seq_show(struct seq_file *seq, void *v)
838 {
839 	static char atm_arp_banner[] =
840 	    "IPitf TypeEncp Idle IP address      ATM address\n";
841 
842 	if (v == SEQ_START_TOKEN) {
843 		seq_puts(seq, atm_arp_banner);
844 	} else {
845 		struct clip_seq_state *state = seq->private;
846 		struct clip_vcc *vcc = state->vcc;
847 		struct neighbour *n = v;
848 
849 		atmarp_info(seq, n, neighbour_priv(n), vcc);
850 	}
851 	return 0;
852 }
853 
854 static const struct seq_operations arp_seq_ops = {
855 	.start	= clip_seq_start,
856 	.next	= neigh_seq_next,
857 	.stop	= neigh_seq_stop,
858 	.show	= clip_seq_show,
859 };
860 
861 static int arp_seq_open(struct inode *inode, struct file *file)
862 {
863 	return seq_open_net(inode, file, &arp_seq_ops,
864 			    sizeof(struct clip_seq_state));
865 }
866 
867 static const struct file_operations arp_seq_fops = {
868 	.open		= arp_seq_open,
869 	.read		= seq_read,
870 	.llseek		= seq_lseek,
871 	.release	= seq_release_net,
872 	.owner		= THIS_MODULE
873 };
874 #endif
875 
876 static void atm_clip_exit_noproc(void);
877 
878 static int __init atm_clip_init(void)
879 {
880 	register_atm_ioctl(&clip_ioctl_ops);
881 	register_netdevice_notifier(&clip_dev_notifier);
882 	register_inetaddr_notifier(&clip_inet_notifier);
883 
884 	setup_timer(&idle_timer, idle_timer_check, 0);
885 
886 #ifdef CONFIG_PROC_FS
887 	{
888 		struct proc_dir_entry *p;
889 
890 		p = proc_create("arp", S_IRUGO, atm_proc_root, &arp_seq_fops);
891 		if (!p) {
892 			pr_err("Unable to initialize /proc/net/atm/arp\n");
893 			atm_clip_exit_noproc();
894 			return -ENOMEM;
895 		}
896 	}
897 #endif
898 
899 	return 0;
900 }
901 
902 static void atm_clip_exit_noproc(void)
903 {
904 	struct net_device *dev, *next;
905 
906 	unregister_inetaddr_notifier(&clip_inet_notifier);
907 	unregister_netdevice_notifier(&clip_dev_notifier);
908 
909 	deregister_atm_ioctl(&clip_ioctl_ops);
910 
911 	/* First, stop the idle timer, so it stops banging
912 	 * on the table.
913 	 */
914 	del_timer_sync(&idle_timer);
915 
916 	dev = clip_devs;
917 	while (dev) {
918 		next = PRIV(dev)->next;
919 		unregister_netdev(dev);
920 		free_netdev(dev);
921 		dev = next;
922 	}
923 }
924 
925 static void __exit atm_clip_exit(void)
926 {
927 	remove_proc_entry("arp", atm_proc_root);
928 
929 	atm_clip_exit_noproc();
930 }
931 
932 module_init(atm_clip_init);
933 module_exit(atm_clip_exit);
934 MODULE_AUTHOR("Werner Almesberger");
935 MODULE_DESCRIPTION("Classical/IP over ATM interface");
936 MODULE_LICENSE("GPL");
937