xref: /openbmc/linux/net/atm/clip.c (revision 9726bfcd)
1  // SPDX-License-Identifier: GPL-2.0-only
2  /* net/atm/clip.c - RFC1577 Classical IP over ATM */
3  
4  /* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
5  
6  #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
7  
8  #include <linux/string.h>
9  #include <linux/errno.h>
10  #include <linux/kernel.h> /* for UINT_MAX */
11  #include <linux/module.h>
12  #include <linux/init.h>
13  #include <linux/netdevice.h>
14  #include <linux/skbuff.h>
15  #include <linux/wait.h>
16  #include <linux/timer.h>
17  #include <linux/if_arp.h> /* for some manifest constants */
18  #include <linux/notifier.h>
19  #include <linux/atm.h>
20  #include <linux/atmdev.h>
21  #include <linux/atmclip.h>
22  #include <linux/atmarp.h>
23  #include <linux/capability.h>
24  #include <linux/ip.h> /* for net/route.h */
25  #include <linux/in.h> /* for struct sockaddr_in */
26  #include <linux/if.h> /* for IFF_UP */
27  #include <linux/inetdevice.h>
28  #include <linux/bitops.h>
29  #include <linux/poison.h>
30  #include <linux/proc_fs.h>
31  #include <linux/seq_file.h>
32  #include <linux/rcupdate.h>
33  #include <linux/jhash.h>
34  #include <linux/slab.h>
35  #include <net/route.h> /* for struct rtable and routing */
36  #include <net/icmp.h> /* icmp_send */
37  #include <net/arp.h>
38  #include <linux/param.h> /* for HZ */
39  #include <linux/uaccess.h>
40  #include <asm/byteorder.h> /* for htons etc. */
41  #include <linux/atomic.h>
42  
43  #include "common.h"
44  #include "resources.h"
45  #include <net/atmclip.h>
46  
47  static struct net_device *clip_devs;
48  static struct atm_vcc *atmarpd;
49  static struct timer_list idle_timer;
50  static const struct neigh_ops clip_neigh_ops;
51  
52  static int to_atmarpd(enum atmarp_ctrl_type type, int itf, __be32 ip)
53  {
54  	struct sock *sk;
55  	struct atmarp_ctrl *ctrl;
56  	struct sk_buff *skb;
57  
58  	pr_debug("(%d)\n", type);
59  	if (!atmarpd)
60  		return -EUNATCH;
61  	skb = alloc_skb(sizeof(struct atmarp_ctrl), GFP_ATOMIC);
62  	if (!skb)
63  		return -ENOMEM;
64  	ctrl = skb_put(skb, sizeof(struct atmarp_ctrl));
65  	ctrl->type = type;
66  	ctrl->itf_num = itf;
67  	ctrl->ip = ip;
68  	atm_force_charge(atmarpd, skb->truesize);
69  
70  	sk = sk_atm(atmarpd);
71  	skb_queue_tail(&sk->sk_receive_queue, skb);
72  	sk->sk_data_ready(sk);
73  	return 0;
74  }
75  
76  static void link_vcc(struct clip_vcc *clip_vcc, struct atmarp_entry *entry)
77  {
78  	pr_debug("%p to entry %p (neigh %p)\n", clip_vcc, entry, entry->neigh);
79  	clip_vcc->entry = entry;
80  	clip_vcc->xoff = 0;	/* @@@ may overrun buffer by one packet */
81  	clip_vcc->next = entry->vccs;
82  	entry->vccs = clip_vcc;
83  	entry->neigh->used = jiffies;
84  }
85  
86  static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
87  {
88  	struct atmarp_entry *entry = clip_vcc->entry;
89  	struct clip_vcc **walk;
90  
91  	if (!entry) {
92  		pr_crit("!clip_vcc->entry (clip_vcc %p)\n", clip_vcc);
93  		return;
94  	}
95  	netif_tx_lock_bh(entry->neigh->dev);	/* block clip_start_xmit() */
96  	entry->neigh->used = jiffies;
97  	for (walk = &entry->vccs; *walk; walk = &(*walk)->next)
98  		if (*walk == clip_vcc) {
99  			int error;
100  
101  			*walk = clip_vcc->next;	/* atomic */
102  			clip_vcc->entry = NULL;
103  			if (clip_vcc->xoff)
104  				netif_wake_queue(entry->neigh->dev);
105  			if (entry->vccs)
106  				goto out;
107  			entry->expires = jiffies - 1;
108  			/* force resolution or expiration */
109  			error = neigh_update(entry->neigh, NULL, NUD_NONE,
110  					     NEIGH_UPDATE_F_ADMIN, 0);
111  			if (error)
112  				pr_crit("neigh_update failed with %d\n", error);
113  			goto out;
114  		}
115  	pr_crit("ATMARP: failed (entry %p, vcc 0x%p)\n", entry, clip_vcc);
116  out:
117  	netif_tx_unlock_bh(entry->neigh->dev);
118  }
119  
120  /* The neighbour entry n->lock is held. */
121  static int neigh_check_cb(struct neighbour *n)
122  {
123  	struct atmarp_entry *entry = neighbour_priv(n);
124  	struct clip_vcc *cv;
125  
126  	if (n->ops != &clip_neigh_ops)
127  		return 0;
128  	for (cv = entry->vccs; cv; cv = cv->next) {
129  		unsigned long exp = cv->last_use + cv->idle_timeout;
130  
131  		if (cv->idle_timeout && time_after(jiffies, exp)) {
132  			pr_debug("releasing vcc %p->%p of entry %p\n",
133  				 cv, cv->vcc, entry);
134  			vcc_release_async(cv->vcc, -ETIMEDOUT);
135  		}
136  	}
137  
138  	if (entry->vccs || time_before(jiffies, entry->expires))
139  		return 0;
140  
141  	if (refcount_read(&n->refcnt) > 1) {
142  		struct sk_buff *skb;
143  
144  		pr_debug("destruction postponed with ref %d\n",
145  			 refcount_read(&n->refcnt));
146  
147  		while ((skb = skb_dequeue(&n->arp_queue)) != NULL)
148  			dev_kfree_skb(skb);
149  
150  		return 0;
151  	}
152  
153  	pr_debug("expired neigh %p\n", n);
154  	return 1;
155  }
156  
157  static void idle_timer_check(struct timer_list *unused)
158  {
159  	write_lock(&arp_tbl.lock);
160  	__neigh_for_each_release(&arp_tbl, neigh_check_cb);
161  	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
162  	write_unlock(&arp_tbl.lock);
163  }
164  
165  static int clip_arp_rcv(struct sk_buff *skb)
166  {
167  	struct atm_vcc *vcc;
168  
169  	pr_debug("\n");
170  	vcc = ATM_SKB(skb)->vcc;
171  	if (!vcc || !atm_charge(vcc, skb->truesize)) {
172  		dev_kfree_skb_any(skb);
173  		return 0;
174  	}
175  	pr_debug("pushing to %p\n", vcc);
176  	pr_debug("using %p\n", CLIP_VCC(vcc)->old_push);
177  	CLIP_VCC(vcc)->old_push(vcc, skb);
178  	return 0;
179  }
180  
181  static const unsigned char llc_oui[] = {
182  	0xaa,	/* DSAP: non-ISO */
183  	0xaa,	/* SSAP: non-ISO */
184  	0x03,	/* Ctrl: Unnumbered Information Command PDU */
185  	0x00,	/* OUI: EtherType */
186  	0x00,
187  	0x00
188  };
189  
190  static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb)
191  {
192  	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
193  
194  	pr_debug("\n");
195  
196  	if (!clip_devs) {
197  		atm_return(vcc, skb->truesize);
198  		kfree_skb(skb);
199  		return;
200  	}
201  
202  	if (!skb) {
203  		pr_debug("removing VCC %p\n", clip_vcc);
204  		if (clip_vcc->entry)
205  			unlink_clip_vcc(clip_vcc);
206  		clip_vcc->old_push(vcc, NULL);	/* pass on the bad news */
207  		kfree(clip_vcc);
208  		return;
209  	}
210  	atm_return(vcc, skb->truesize);
211  	skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;
212  	/* clip_vcc->entry == NULL if we don't have an IP address yet */
213  	if (!skb->dev) {
214  		dev_kfree_skb_any(skb);
215  		return;
216  	}
217  	ATM_SKB(skb)->vcc = vcc;
218  	skb_reset_mac_header(skb);
219  	if (!clip_vcc->encap ||
220  	    skb->len < RFC1483LLC_LEN ||
221  	    memcmp(skb->data, llc_oui, sizeof(llc_oui)))
222  		skb->protocol = htons(ETH_P_IP);
223  	else {
224  		skb->protocol = ((__be16 *)skb->data)[3];
225  		skb_pull(skb, RFC1483LLC_LEN);
226  		if (skb->protocol == htons(ETH_P_ARP)) {
227  			skb->dev->stats.rx_packets++;
228  			skb->dev->stats.rx_bytes += skb->len;
229  			clip_arp_rcv(skb);
230  			return;
231  		}
232  	}
233  	clip_vcc->last_use = jiffies;
234  	skb->dev->stats.rx_packets++;
235  	skb->dev->stats.rx_bytes += skb->len;
236  	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
237  	netif_rx(skb);
238  }
239  
240  /*
241   * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that
242   * clip_pop is atomic with respect to the critical section in clip_start_xmit.
243   */
244  
245  static void clip_pop(struct atm_vcc *vcc, struct sk_buff *skb)
246  {
247  	struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
248  	struct net_device *dev = skb->dev;
249  	int old;
250  	unsigned long flags;
251  
252  	pr_debug("(vcc %p)\n", vcc);
253  	clip_vcc->old_pop(vcc, skb);
254  	/* skb->dev == NULL in outbound ARP packets */
255  	if (!dev)
256  		return;
257  	spin_lock_irqsave(&PRIV(dev)->xoff_lock, flags);
258  	if (atm_may_send(vcc, 0)) {
259  		old = xchg(&clip_vcc->xoff, 0);
260  		if (old)
261  			netif_wake_queue(dev);
262  	}
263  	spin_unlock_irqrestore(&PRIV(dev)->xoff_lock, flags);
264  }
265  
266  static void clip_neigh_solicit(struct neighbour *neigh, struct sk_buff *skb)
267  {
268  	__be32 *ip = (__be32 *) neigh->primary_key;
269  
270  	pr_debug("(neigh %p, skb %p)\n", neigh, skb);
271  	to_atmarpd(act_need, PRIV(neigh->dev)->number, *ip);
272  }
273  
274  static void clip_neigh_error(struct neighbour *neigh, struct sk_buff *skb)
275  {
276  #ifndef CONFIG_ATM_CLIP_NO_ICMP
277  	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
278  #endif
279  	kfree_skb(skb);
280  }
281  
282  static const struct neigh_ops clip_neigh_ops = {
283  	.family =		AF_INET,
284  	.solicit =		clip_neigh_solicit,
285  	.error_report =		clip_neigh_error,
286  	.output =		neigh_direct_output,
287  	.connected_output =	neigh_direct_output,
288  };
289  
290  static int clip_constructor(struct net_device *dev, struct neighbour *neigh)
291  {
292  	struct atmarp_entry *entry = neighbour_priv(neigh);
293  
294  	if (neigh->tbl->family != AF_INET)
295  		return -EINVAL;
296  
297  	if (neigh->type != RTN_UNICAST)
298  		return -EINVAL;
299  
300  	neigh->nud_state = NUD_NONE;
301  	neigh->ops = &clip_neigh_ops;
302  	neigh->output = neigh->ops->output;
303  	entry->neigh = neigh;
304  	entry->vccs = NULL;
305  	entry->expires = jiffies - 1;
306  
307  	return 0;
308  }
309  
310  /* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */
311  
312  /*
313   * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means
314   * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,
315   * don't increment the usage count. This is used to create entries in
316   * clip_setentry.
317   */
318  
319  static int clip_encap(struct atm_vcc *vcc, int mode)
320  {
321  	if (!CLIP_VCC(vcc))
322  		return -EBADFD;
323  
324  	CLIP_VCC(vcc)->encap = mode;
325  	return 0;
326  }
327  
328  static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
329  				   struct net_device *dev)
330  {
331  	struct clip_priv *clip_priv = PRIV(dev);
332  	struct dst_entry *dst = skb_dst(skb);
333  	struct atmarp_entry *entry;
334  	struct neighbour *n;
335  	struct atm_vcc *vcc;
336  	struct rtable *rt;
337  	__be32 *daddr;
338  	int old;
339  	unsigned long flags;
340  
341  	pr_debug("(skb %p)\n", skb);
342  	if (!dst) {
343  		pr_err("skb_dst(skb) == NULL\n");
344  		dev_kfree_skb(skb);
345  		dev->stats.tx_dropped++;
346  		return NETDEV_TX_OK;
347  	}
348  	rt = (struct rtable *) dst;
349  	if (rt->rt_gw_family == AF_INET)
350  		daddr = &rt->rt_gw4;
351  	else
352  		daddr = &ip_hdr(skb)->daddr;
353  	n = dst_neigh_lookup(dst, daddr);
354  	if (!n) {
355  		pr_err("NO NEIGHBOUR !\n");
356  		dev_kfree_skb(skb);
357  		dev->stats.tx_dropped++;
358  		return NETDEV_TX_OK;
359  	}
360  	entry = neighbour_priv(n);
361  	if (!entry->vccs) {
362  		if (time_after(jiffies, entry->expires)) {
363  			/* should be resolved */
364  			entry->expires = jiffies + ATMARP_RETRY_DELAY * HZ;
365  			to_atmarpd(act_need, PRIV(dev)->number, *((__be32 *)n->primary_key));
366  		}
367  		if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)
368  			skb_queue_tail(&entry->neigh->arp_queue, skb);
369  		else {
370  			dev_kfree_skb(skb);
371  			dev->stats.tx_dropped++;
372  		}
373  		goto out_release_neigh;
374  	}
375  	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
376  	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
377  	pr_debug("using neighbour %p, vcc %p\n", n, vcc);
378  	if (entry->vccs->encap) {
379  		void *here;
380  
381  		here = skb_push(skb, RFC1483LLC_LEN);
382  		memcpy(here, llc_oui, sizeof(llc_oui));
383  		((__be16 *) here)[3] = skb->protocol;
384  	}
385  	atm_account_tx(vcc, skb);
386  	entry->vccs->last_use = jiffies;
387  	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
388  	old = xchg(&entry->vccs->xoff, 1);	/* assume XOFF ... */
389  	if (old) {
390  		pr_warn("XOFF->XOFF transition\n");
391  		goto out_release_neigh;
392  	}
393  	dev->stats.tx_packets++;
394  	dev->stats.tx_bytes += skb->len;
395  	vcc->send(vcc, skb);
396  	if (atm_may_send(vcc, 0)) {
397  		entry->vccs->xoff = 0;
398  		goto out_release_neigh;
399  	}
400  	spin_lock_irqsave(&clip_priv->xoff_lock, flags);
401  	netif_stop_queue(dev);	/* XOFF -> throttle immediately */
402  	barrier();
403  	if (!entry->vccs->xoff)
404  		netif_start_queue(dev);
405  	/* Oh, we just raced with clip_pop. netif_start_queue should be
406  	   good enough, because nothing should really be asleep because
407  	   of the brief netif_stop_queue. If this isn't true or if it
408  	   changes, use netif_wake_queue instead. */
409  	spin_unlock_irqrestore(&clip_priv->xoff_lock, flags);
410  out_release_neigh:
411  	neigh_release(n);
412  	return NETDEV_TX_OK;
413  }
414  
415  static int clip_mkip(struct atm_vcc *vcc, int timeout)
416  {
417  	struct clip_vcc *clip_vcc;
418  
419  	if (!vcc->push)
420  		return -EBADFD;
421  	clip_vcc = kmalloc(sizeof(struct clip_vcc), GFP_KERNEL);
422  	if (!clip_vcc)
423  		return -ENOMEM;
424  	pr_debug("%p vcc %p\n", clip_vcc, vcc);
425  	clip_vcc->vcc = vcc;
426  	vcc->user_back = clip_vcc;
427  	set_bit(ATM_VF_IS_CLIP, &vcc->flags);
428  	clip_vcc->entry = NULL;
429  	clip_vcc->xoff = 0;
430  	clip_vcc->encap = 1;
431  	clip_vcc->last_use = jiffies;
432  	clip_vcc->idle_timeout = timeout * HZ;
433  	clip_vcc->old_push = vcc->push;
434  	clip_vcc->old_pop = vcc->pop;
435  	vcc->push = clip_push;
436  	vcc->pop = clip_pop;
437  
438  	/* re-process everything received between connection setup and MKIP */
439  	vcc_process_recv_queue(vcc);
440  
441  	return 0;
442  }
443  
444  static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
445  {
446  	struct neighbour *neigh;
447  	struct atmarp_entry *entry;
448  	int error;
449  	struct clip_vcc *clip_vcc;
450  	struct rtable *rt;
451  
452  	if (vcc->push != clip_push) {
453  		pr_warn("non-CLIP VCC\n");
454  		return -EBADF;
455  	}
456  	clip_vcc = CLIP_VCC(vcc);
457  	if (!ip) {
458  		if (!clip_vcc->entry) {
459  			pr_err("hiding hidden ATMARP entry\n");
460  			return 0;
461  		}
462  		pr_debug("remove\n");
463  		unlink_clip_vcc(clip_vcc);
464  		return 0;
465  	}
466  	rt = ip_route_output(&init_net, ip, 0, 1, 0);
467  	if (IS_ERR(rt))
468  		return PTR_ERR(rt);
469  	neigh = __neigh_lookup(&arp_tbl, &ip, rt->dst.dev, 1);
470  	ip_rt_put(rt);
471  	if (!neigh)
472  		return -ENOMEM;
473  	entry = neighbour_priv(neigh);
474  	if (entry != clip_vcc->entry) {
475  		if (!clip_vcc->entry)
476  			pr_debug("add\n");
477  		else {
478  			pr_debug("update\n");
479  			unlink_clip_vcc(clip_vcc);
480  		}
481  		link_vcc(clip_vcc, entry);
482  	}
483  	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
484  			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN, 0);
485  	neigh_release(neigh);
486  	return error;
487  }
488  
489  static const struct net_device_ops clip_netdev_ops = {
490  	.ndo_start_xmit		= clip_start_xmit,
491  	.ndo_neigh_construct	= clip_constructor,
492  };
493  
494  static void clip_setup(struct net_device *dev)
495  {
496  	dev->netdev_ops = &clip_netdev_ops;
497  	dev->type = ARPHRD_ATM;
498  	dev->neigh_priv_len = sizeof(struct atmarp_entry);
499  	dev->hard_header_len = RFC1483LLC_LEN;
500  	dev->mtu = RFC1626_MTU;
501  	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
502  	/* When using a "real" qdisc, the qdisc determines the queue */
503  	/* length. tx_queue_len is only used for the default case, */
504  	/* without any more elaborate queuing. 100 is a reasonable */
505  	/* compromise between decent burst-tolerance and protection */
506  	/* against memory hogs. */
507  	netif_keep_dst(dev);
508  }
509  
510  static int clip_create(int number)
511  {
512  	struct net_device *dev;
513  	struct clip_priv *clip_priv;
514  	int error;
515  
516  	if (number != -1) {
517  		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
518  			if (PRIV(dev)->number == number)
519  				return -EEXIST;
520  	} else {
521  		number = 0;
522  		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
523  			if (PRIV(dev)->number >= number)
524  				number = PRIV(dev)->number + 1;
525  	}
526  	dev = alloc_netdev(sizeof(struct clip_priv), "", NET_NAME_UNKNOWN,
527  			   clip_setup);
528  	if (!dev)
529  		return -ENOMEM;
530  	clip_priv = PRIV(dev);
531  	sprintf(dev->name, "atm%d", number);
532  	spin_lock_init(&clip_priv->xoff_lock);
533  	clip_priv->number = number;
534  	error = register_netdev(dev);
535  	if (error) {
536  		free_netdev(dev);
537  		return error;
538  	}
539  	clip_priv->next = clip_devs;
540  	clip_devs = dev;
541  	pr_debug("registered (net:%s)\n", dev->name);
542  	return number;
543  }
544  
545  static int clip_device_event(struct notifier_block *this, unsigned long event,
546  			     void *ptr)
547  {
548  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
549  
550  	if (!net_eq(dev_net(dev), &init_net))
551  		return NOTIFY_DONE;
552  
553  	if (event == NETDEV_UNREGISTER)
554  		return NOTIFY_DONE;
555  
556  	/* ignore non-CLIP devices */
557  	if (dev->type != ARPHRD_ATM || dev->netdev_ops != &clip_netdev_ops)
558  		return NOTIFY_DONE;
559  
560  	switch (event) {
561  	case NETDEV_UP:
562  		pr_debug("NETDEV_UP\n");
563  		to_atmarpd(act_up, PRIV(dev)->number, 0);
564  		break;
565  	case NETDEV_GOING_DOWN:
566  		pr_debug("NETDEV_DOWN\n");
567  		to_atmarpd(act_down, PRIV(dev)->number, 0);
568  		break;
569  	case NETDEV_CHANGE:
570  	case NETDEV_CHANGEMTU:
571  		pr_debug("NETDEV_CHANGE*\n");
572  		to_atmarpd(act_change, PRIV(dev)->number, 0);
573  		break;
574  	}
575  	return NOTIFY_DONE;
576  }
577  
578  static int clip_inet_event(struct notifier_block *this, unsigned long event,
579  			   void *ifa)
580  {
581  	struct in_device *in_dev;
582  	struct netdev_notifier_info info;
583  
584  	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
585  	/*
586  	 * Transitions are of the down-change-up type, so it's sufficient to
587  	 * handle the change on up.
588  	 */
589  	if (event != NETDEV_UP)
590  		return NOTIFY_DONE;
591  	netdev_notifier_info_init(&info, in_dev->dev);
592  	return clip_device_event(this, NETDEV_CHANGE, &info);
593  }
594  
595  static struct notifier_block clip_dev_notifier = {
596  	.notifier_call = clip_device_event,
597  };
598  
599  
600  
601  static struct notifier_block clip_inet_notifier = {
602  	.notifier_call = clip_inet_event,
603  };
604  
605  
606  
607  static void atmarpd_close(struct atm_vcc *vcc)
608  {
609  	pr_debug("\n");
610  
611  	rtnl_lock();
612  	atmarpd = NULL;
613  	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
614  	rtnl_unlock();
615  
616  	pr_debug("(done)\n");
617  	module_put(THIS_MODULE);
618  }
619  
620  static const struct atmdev_ops atmarpd_dev_ops = {
621  	.close = atmarpd_close
622  };
623  
624  
625  static struct atm_dev atmarpd_dev = {
626  	.ops =			&atmarpd_dev_ops,
627  	.type =			"arpd",
628  	.number = 		999,
629  	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
630  };
631  
632  
633  static int atm_init_atmarp(struct atm_vcc *vcc)
634  {
635  	rtnl_lock();
636  	if (atmarpd) {
637  		rtnl_unlock();
638  		return -EADDRINUSE;
639  	}
640  
641  	mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ);
642  
643  	atmarpd = vcc;
644  	set_bit(ATM_VF_META, &vcc->flags);
645  	set_bit(ATM_VF_READY, &vcc->flags);
646  	    /* allow replies and avoid getting closed if signaling dies */
647  	vcc->dev = &atmarpd_dev;
648  	vcc_insert_socket(sk_atm(vcc));
649  	vcc->push = NULL;
650  	vcc->pop = NULL; /* crash */
651  	vcc->push_oam = NULL; /* crash */
652  	rtnl_unlock();
653  	return 0;
654  }
655  
656  static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
657  {
658  	struct atm_vcc *vcc = ATM_SD(sock);
659  	int err = 0;
660  
661  	switch (cmd) {
662  	case SIOCMKCLIP:
663  	case ATMARPD_CTRL:
664  	case ATMARP_MKIP:
665  	case ATMARP_SETENTRY:
666  	case ATMARP_ENCAP:
667  		if (!capable(CAP_NET_ADMIN))
668  			return -EPERM;
669  		break;
670  	default:
671  		return -ENOIOCTLCMD;
672  	}
673  
674  	switch (cmd) {
675  	case SIOCMKCLIP:
676  		err = clip_create(arg);
677  		break;
678  	case ATMARPD_CTRL:
679  		err = atm_init_atmarp(vcc);
680  		if (!err) {
681  			sock->state = SS_CONNECTED;
682  			__module_get(THIS_MODULE);
683  		}
684  		break;
685  	case ATMARP_MKIP:
686  		err = clip_mkip(vcc, arg);
687  		break;
688  	case ATMARP_SETENTRY:
689  		err = clip_setentry(vcc, (__force __be32)arg);
690  		break;
691  	case ATMARP_ENCAP:
692  		err = clip_encap(vcc, arg);
693  		break;
694  	}
695  	return err;
696  }
697  
698  static struct atm_ioctl clip_ioctl_ops = {
699  	.owner = THIS_MODULE,
700  	.ioctl = clip_ioctl,
701  };
702  
703  #ifdef CONFIG_PROC_FS
704  
705  static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
706  {
707  	static int code[] = { 1, 2, 10, 6, 1, 0 };
708  	static int e164[] = { 1, 8, 4, 6, 1, 0 };
709  
710  	if (*addr->sas_addr.pub) {
711  		seq_printf(seq, "%s", addr->sas_addr.pub);
712  		if (*addr->sas_addr.prv)
713  			seq_putc(seq, '+');
714  	} else if (!*addr->sas_addr.prv) {
715  		seq_printf(seq, "%s", "(none)");
716  		return;
717  	}
718  	if (*addr->sas_addr.prv) {
719  		unsigned char *prv = addr->sas_addr.prv;
720  		int *fields;
721  		int i, j;
722  
723  		fields = *prv == ATM_AFI_E164 ? e164 : code;
724  		for (i = 0; fields[i]; i++) {
725  			for (j = fields[i]; j; j--)
726  				seq_printf(seq, "%02X", *prv++);
727  			if (fields[i + 1])
728  				seq_putc(seq, '.');
729  		}
730  	}
731  }
732  
733  /* This means the neighbour entry has no attached VCC objects. */
734  #define SEQ_NO_VCC_TOKEN	((void *) 2)
735  
736  static void atmarp_info(struct seq_file *seq, struct neighbour *n,
737  			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
738  {
739  	struct net_device *dev = n->dev;
740  	unsigned long exp;
741  	char buf[17];
742  	int svc, llc, off;
743  
744  	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
745  	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));
746  
747  	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);
748  
749  	if (clip_vcc == SEQ_NO_VCC_TOKEN)
750  		exp = entry->neigh->used;
751  	else
752  		exp = clip_vcc->last_use;
753  
754  	exp = (jiffies - exp) / HZ;
755  
756  	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
757  		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);
758  
759  	off = scnprintf(buf, sizeof(buf) - 1, "%pI4", n->primary_key);
760  	while (off < 16)
761  		buf[off++] = ' ';
762  	buf[off] = '\0';
763  	seq_printf(seq, "%s", buf);
764  
765  	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
766  		if (time_before(jiffies, entry->expires))
767  			seq_printf(seq, "(resolving)\n");
768  		else
769  			seq_printf(seq, "(expired, ref %d)\n",
770  				   refcount_read(&entry->neigh->refcnt));
771  	} else if (!svc) {
772  		seq_printf(seq, "%d.%d.%d\n",
773  			   clip_vcc->vcc->dev->number,
774  			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
775  	} else {
776  		svc_addr(seq, &clip_vcc->vcc->remote);
777  		seq_putc(seq, '\n');
778  	}
779  }
780  
781  struct clip_seq_state {
782  	/* This member must be first. */
783  	struct neigh_seq_state ns;
784  
785  	/* Local to clip specific iteration. */
786  	struct clip_vcc *vcc;
787  };
788  
789  static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
790  					  struct clip_vcc *curr)
791  {
792  	if (!curr) {
793  		curr = e->vccs;
794  		if (!curr)
795  			return SEQ_NO_VCC_TOKEN;
796  		return curr;
797  	}
798  	if (curr == SEQ_NO_VCC_TOKEN)
799  		return NULL;
800  
801  	curr = curr->next;
802  
803  	return curr;
804  }
805  
806  static void *clip_seq_vcc_walk(struct clip_seq_state *state,
807  			       struct atmarp_entry *e, loff_t * pos)
808  {
809  	struct clip_vcc *vcc = state->vcc;
810  
811  	vcc = clip_seq_next_vcc(e, vcc);
812  	if (vcc && pos != NULL) {
813  		while (*pos) {
814  			vcc = clip_seq_next_vcc(e, vcc);
815  			if (!vcc)
816  				break;
817  			--(*pos);
818  		}
819  	}
820  	state->vcc = vcc;
821  
822  	return vcc;
823  }
824  
825  static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
826  			       struct neighbour *n, loff_t * pos)
827  {
828  	struct clip_seq_state *state = (struct clip_seq_state *)_state;
829  
830  	if (n->dev->type != ARPHRD_ATM)
831  		return NULL;
832  
833  	return clip_seq_vcc_walk(state, neighbour_priv(n), pos);
834  }
835  
836  static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
837  {
838  	struct clip_seq_state *state = seq->private;
839  	state->ns.neigh_sub_iter = clip_seq_sub_iter;
840  	return neigh_seq_start(seq, pos, &arp_tbl, NEIGH_SEQ_NEIGH_ONLY);
841  }
842  
843  static int clip_seq_show(struct seq_file *seq, void *v)
844  {
845  	static char atm_arp_banner[] =
846  	    "IPitf TypeEncp Idle IP address      ATM address\n";
847  
848  	if (v == SEQ_START_TOKEN) {
849  		seq_puts(seq, atm_arp_banner);
850  	} else {
851  		struct clip_seq_state *state = seq->private;
852  		struct clip_vcc *vcc = state->vcc;
853  		struct neighbour *n = v;
854  
855  		atmarp_info(seq, n, neighbour_priv(n), vcc);
856  	}
857  	return 0;
858  }
859  
860  static const struct seq_operations arp_seq_ops = {
861  	.start	= clip_seq_start,
862  	.next	= neigh_seq_next,
863  	.stop	= neigh_seq_stop,
864  	.show	= clip_seq_show,
865  };
866  #endif
867  
868  static void atm_clip_exit_noproc(void);
869  
870  static int __init atm_clip_init(void)
871  {
872  	register_atm_ioctl(&clip_ioctl_ops);
873  	register_netdevice_notifier(&clip_dev_notifier);
874  	register_inetaddr_notifier(&clip_inet_notifier);
875  
876  	timer_setup(&idle_timer, idle_timer_check, 0);
877  
878  #ifdef CONFIG_PROC_FS
879  	{
880  		struct proc_dir_entry *p;
881  
882  		p = proc_create_net("arp", 0444, atm_proc_root, &arp_seq_ops,
883  				sizeof(struct clip_seq_state));
884  		if (!p) {
885  			pr_err("Unable to initialize /proc/net/atm/arp\n");
886  			atm_clip_exit_noproc();
887  			return -ENOMEM;
888  		}
889  	}
890  #endif
891  
892  	return 0;
893  }
894  
895  static void atm_clip_exit_noproc(void)
896  {
897  	struct net_device *dev, *next;
898  
899  	unregister_inetaddr_notifier(&clip_inet_notifier);
900  	unregister_netdevice_notifier(&clip_dev_notifier);
901  
902  	deregister_atm_ioctl(&clip_ioctl_ops);
903  
904  	/* First, stop the idle timer, so it stops banging
905  	 * on the table.
906  	 */
907  	del_timer_sync(&idle_timer);
908  
909  	dev = clip_devs;
910  	while (dev) {
911  		next = PRIV(dev)->next;
912  		unregister_netdev(dev);
913  		free_netdev(dev);
914  		dev = next;
915  	}
916  }
917  
918  static void __exit atm_clip_exit(void)
919  {
920  	remove_proc_entry("arp", atm_proc_root);
921  
922  	atm_clip_exit_noproc();
923  }
924  
925  module_init(atm_clip_init);
926  module_exit(atm_clip_exit);
927  MODULE_AUTHOR("Werner Almesberger");
928  MODULE_DESCRIPTION("Classical/IP over ATM interface");
929  MODULE_LICENSE("GPL");
930