dn_neigh.c revision d1a649838802edd94b6335834919463c6ae61f40 
1/*
2 * DECnet       An implementation of the DECnet protocol suite for the LINUX
3 *              operating system.  DECnet is implemented using the  BSD Socket
4 *              interface as the means of communication with the user level.
5 *
6 *              DECnet Neighbour Functions (Adjacency Database and
7 *                                                        On-Ethernet Cache)
8 *
9 * Author:      Steve Whitehouse <SteveW@ACM.org>
10 *
11 *
12 * Changes:
13 *     Steve Whitehouse     : Fixed router listing routine
14 *     Steve Whitehouse     : Added error_report functions
15 *     Steve Whitehouse     : Added default router detection
16 *     Steve Whitehouse     : Hop counts in outgoing messages
17 *     Steve Whitehouse     : Fixed src/dst in outgoing messages so
18 *                            forwarding now stands a good chance of
19 *                            working.
20 *     Steve Whitehouse     : Fixed neighbour states (for now anyway).
21 *     Steve Whitehouse     : Made error_report functions dummies. This
22 *                            is not the right place to return skbs.
23 *     Steve Whitehouse     : Convert to seq_file
24 *
25 */
26
27#include <linux/config.h>
28#include <linux/net.h>
29#include <linux/module.h>
30#include <linux/socket.h>
31#include <linux/if_arp.h>
32#include <linux/if_ether.h>
33#include <linux/init.h>
34#include <linux/proc_fs.h>
35#include <linux/string.h>
36#include <linux/netfilter_decnet.h>
37#include <linux/spinlock.h>
38#include <linux/seq_file.h>
39#include <linux/rcupdate.h>
40#include <linux/jhash.h>
41#include <asm/atomic.h>
42#include <net/neighbour.h>
43#include <net/dst.h>
44#include <net/flow.h>
45#include <net/dn.h>
46#include <net/dn_dev.h>
47#include <net/dn_neigh.h>
48#include <net/dn_route.h>
49
50static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev);
51static int dn_neigh_construct(struct neighbour *);
52static void dn_long_error_report(struct neighbour *, struct sk_buff *);
53static void dn_short_error_report(struct neighbour *, struct sk_buff *);
54static int dn_long_output(struct sk_buff *);
55static int dn_short_output(struct sk_buff *);
56static int dn_phase3_output(struct sk_buff *);
57
58
59/*
60 * For talking to broadcast devices: Ethernet & PPP
61 */
62static struct neigh_ops dn_long_ops = {
63	.family =		AF_DECnet,
64	.error_report =		dn_long_error_report,
65	.output =		dn_long_output,
66	.connected_output =	dn_long_output,
67	.hh_output =		dev_queue_xmit,
68	.queue_xmit =		dev_queue_xmit,
69};
70
71/*
72 * For talking to pointopoint and multidrop devices: DDCMP and X.25
73 */
74static struct neigh_ops dn_short_ops = {
75	.family =		AF_DECnet,
76	.error_report =		dn_short_error_report,
77	.output =		dn_short_output,
78	.connected_output =	dn_short_output,
79	.hh_output =		dev_queue_xmit,
80	.queue_xmit =		dev_queue_xmit,
81};
82
83/*
84 * For talking to DECnet phase III nodes
85 */
86static struct neigh_ops dn_phase3_ops = {
87	.family =		AF_DECnet,
88	.error_report =		dn_short_error_report, /* Can use short version here */
89	.output =		dn_phase3_output,
90	.connected_output =	dn_phase3_output,
91	.hh_output =		dev_queue_xmit,
92	.queue_xmit =		dev_queue_xmit
93};
94
95struct neigh_table dn_neigh_table = {
96	.family =			PF_DECnet,
97	.entry_size =			sizeof(struct dn_neigh),
98	.key_len =			sizeof(__le16),
99	.hash =				dn_neigh_hash,
100	.constructor =			dn_neigh_construct,
101	.id =				"dn_neigh_cache",
102	.parms ={
103		.tbl =			&dn_neigh_table,
104		.base_reachable_time =	30 * HZ,
105		.retrans_time =	1 * HZ,
106		.gc_staletime =	60 * HZ,
107		.reachable_time =		30 * HZ,
108		.delay_probe_time =	5 * HZ,
109		.queue_len =		3,
110		.ucast_probes =	0,
111		.app_probes =		0,
112		.mcast_probes =	0,
113		.anycast_delay =	0,
114		.proxy_delay =		0,
115		.proxy_qlen =		0,
116		.locktime =		1 * HZ,
117	},
118	.gc_interval =			30 * HZ,
119	.gc_thresh1 =			128,
120	.gc_thresh2 =			512,
121	.gc_thresh3 =			1024,
122};
123
124static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev)
125{
126	return jhash_2words(*(__u16 *)pkey, 0, dn_neigh_table.hash_rnd);
127}
128
129static int dn_neigh_construct(struct neighbour *neigh)
130{
131	struct net_device *dev = neigh->dev;
132	struct dn_neigh *dn = (struct dn_neigh *)neigh;
133	struct dn_dev *dn_db;
134	struct neigh_parms *parms;
135
136	rcu_read_lock();
137	dn_db = rcu_dereference(dev->dn_ptr);
138	if (dn_db == NULL) {
139		rcu_read_unlock();
140		return -EINVAL;
141	}
142
143	parms = dn_db->neigh_parms;
144	if (!parms) {
145		rcu_read_unlock();
146		return -EINVAL;
147	}
148
149	__neigh_parms_put(neigh->parms);
150	neigh->parms = neigh_parms_clone(parms);
151
152	if (dn_db->use_long)
153		neigh->ops = &dn_long_ops;
154	else
155		neigh->ops = &dn_short_ops;
156	rcu_read_unlock();
157
158	if (dn->flags & DN_NDFLAG_P3)
159		neigh->ops = &dn_phase3_ops;
160
161	neigh->nud_state = NUD_NOARP;
162	neigh->output = neigh->ops->connected_output;
163
164	if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
165		memcpy(neigh->ha, dev->broadcast, dev->addr_len);
166	else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
167		dn_dn2eth(neigh->ha, dn->addr);
168	else {
169		if (net_ratelimit())
170			printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  dev->type);
171		return -EINVAL;
172	}
173
174	/*
175	 * Make an estimate of the remote block size by assuming that its
176	 * two less then the device mtu, which it true for ethernet (and
177	 * other things which support long format headers) since there is
178	 * an extra length field (of 16 bits) which isn't part of the
179	 * ethernet headers and which the DECnet specs won't admit is part
180	 * of the DECnet routing headers either.
181	 *
182	 * If we over estimate here its no big deal, the NSP negotiations
183	 * will prevent us from sending packets which are too large for the
184	 * remote node to handle. In any case this figure is normally updated
185	 * by a hello message in most cases.
186	 */
187	dn->blksize = dev->mtu - 2;
188
189	return 0;
190}
191
192static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
193{
194	printk(KERN_DEBUG "dn_long_error_report: called\n");
195	kfree_skb(skb);
196}
197
198
199static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
200{
201	printk(KERN_DEBUG "dn_short_error_report: called\n");
202	kfree_skb(skb);
203}
204
205static int dn_neigh_output_packet(struct sk_buff *skb)
206{
207	struct dst_entry *dst = skb->dst;
208	struct dn_route *rt = (struct dn_route *)dst;
209	struct neighbour *neigh = dst->neighbour;
210	struct net_device *dev = neigh->dev;
211	char mac_addr[ETH_ALEN];
212
213	dn_dn2eth(mac_addr, rt->rt_local_src);
214	if (!dev->hard_header || dev->hard_header(skb, dev, ntohs(skb->protocol), neigh->ha, mac_addr, skb->len) >= 0)
215		return neigh->ops->queue_xmit(skb);
216
217	if (net_ratelimit())
218		printk(KERN_DEBUG "dn_neigh_output_packet: oops, can't send packet\n");
219
220	kfree_skb(skb);
221	return -EINVAL;
222}
223
224static int dn_long_output(struct sk_buff *skb)
225{
226	struct dst_entry *dst = skb->dst;
227	struct neighbour *neigh = dst->neighbour;
228	struct net_device *dev = neigh->dev;
229	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
230	unsigned char *data;
231	struct dn_long_packet *lp;
232	struct dn_skb_cb *cb = DN_SKB_CB(skb);
233
234
235	if (skb_headroom(skb) < headroom) {
236		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
237		if (skb2 == NULL) {
238			if (net_ratelimit())
239				printk(KERN_CRIT "dn_long_output: no memory\n");
240			kfree_skb(skb);
241			return -ENOBUFS;
242		}
243		kfree_skb(skb);
244		skb = skb2;
245		if (net_ratelimit())
246			printk(KERN_INFO "dn_long_output: Increasing headroom\n");
247	}
248
249	data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
250	lp = (struct dn_long_packet *)(data+3);
251
252	*((__le16 *)data) = dn_htons(skb->len - 2);
253	*(data + 2) = 1 | DN_RT_F_PF; /* Padding */
254
255	lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
256	lp->d_area   = lp->d_subarea = 0;
257	dn_dn2eth(lp->d_id, cb->dst);
258	lp->s_area   = lp->s_subarea = 0;
259	dn_dn2eth(lp->s_id, cb->src);
260	lp->nl2      = 0;
261	lp->visit_ct = cb->hops & 0x3f;
262	lp->s_class  = 0;
263	lp->pt       = 0;
264
265	skb->nh.raw = skb->data;
266
267	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
268}
269
270static int dn_short_output(struct sk_buff *skb)
271{
272	struct dst_entry *dst = skb->dst;
273	struct neighbour *neigh = dst->neighbour;
274	struct net_device *dev = neigh->dev;
275	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
276	struct dn_short_packet *sp;
277	unsigned char *data;
278	struct dn_skb_cb *cb = DN_SKB_CB(skb);
279
280
281        if (skb_headroom(skb) < headroom) {
282                struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
283                if (skb2 == NULL) {
284			if (net_ratelimit())
285                        	printk(KERN_CRIT "dn_short_output: no memory\n");
286                        kfree_skb(skb);
287                        return -ENOBUFS;
288                }
289                kfree_skb(skb);
290                skb = skb2;
291		if (net_ratelimit())
292                	printk(KERN_INFO "dn_short_output: Increasing headroom\n");
293        }
294
295	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
296	*((__le16 *)data) = dn_htons(skb->len - 2);
297	sp = (struct dn_short_packet *)(data+2);
298
299	sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
300	sp->dstnode    = cb->dst;
301	sp->srcnode    = cb->src;
302	sp->forward    = cb->hops & 0x3f;
303
304	skb->nh.raw = skb->data;
305
306	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
307}
308
309/*
310 * Phase 3 output is the same is short output, execpt that
311 * it clears the area bits before transmission.
312 */
313static int dn_phase3_output(struct sk_buff *skb)
314{
315	struct dst_entry *dst = skb->dst;
316	struct neighbour *neigh = dst->neighbour;
317	struct net_device *dev = neigh->dev;
318	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
319	struct dn_short_packet *sp;
320	unsigned char *data;
321	struct dn_skb_cb *cb = DN_SKB_CB(skb);
322
323	if (skb_headroom(skb) < headroom) {
324		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
325		if (skb2 == NULL) {
326			if (net_ratelimit())
327				printk(KERN_CRIT "dn_phase3_output: no memory\n");
328			kfree_skb(skb);
329			return -ENOBUFS;
330		}
331		kfree_skb(skb);
332		skb = skb2;
333		if (net_ratelimit())
334			printk(KERN_INFO "dn_phase3_output: Increasing headroom\n");
335	}
336
337	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
338	*((__le16 *)data) = dn_htons(skb->len - 2);
339	sp = (struct dn_short_packet *)(data + 2);
340
341	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
342	sp->dstnode  = cb->dst & dn_htons(0x03ff);
343	sp->srcnode  = cb->src & dn_htons(0x03ff);
344	sp->forward  = cb->hops & 0x3f;
345
346	skb->nh.raw = skb->data;
347
348	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
349}
350
351/*
352 * Unfortunately, the neighbour code uses the device in its hash
353 * function, so we don't get any advantage from it. This function
354 * basically does a neigh_lookup(), but without comparing the device
355 * field. This is required for the On-Ethernet cache
356 */
357
358/*
359 * Pointopoint link receives a hello message
360 */
361void dn_neigh_pointopoint_hello(struct sk_buff *skb)
362{
363	kfree_skb(skb);
364}
365
366/*
367 * Ethernet router hello message received
368 */
369int dn_neigh_router_hello(struct sk_buff *skb)
370{
371	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
372
373	struct neighbour *neigh;
374	struct dn_neigh *dn;
375	struct dn_dev *dn_db;
376	__le16 src;
377
378	src = dn_eth2dn(msg->id);
379
380	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
381
382	dn = (struct dn_neigh *)neigh;
383
384	if (neigh) {
385		write_lock(&neigh->lock);
386
387		neigh->used = jiffies;
388		dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
389
390		if (!(neigh->nud_state & NUD_PERMANENT)) {
391			neigh->updated = jiffies;
392
393			if (neigh->dev->type == ARPHRD_ETHER)
394				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
395
396			dn->blksize  = dn_ntohs(msg->blksize);
397			dn->priority = msg->priority;
398
399			dn->flags &= ~DN_NDFLAG_P3;
400
401			switch(msg->iinfo & DN_RT_INFO_TYPE) {
402				case DN_RT_INFO_L1RT:
403					dn->flags &=~DN_NDFLAG_R2;
404					dn->flags |= DN_NDFLAG_R1;
405					break;
406				case DN_RT_INFO_L2RT:
407					dn->flags |= DN_NDFLAG_R2;
408			}
409		}
410
411		/* Only use routers in our area */
412		if ((dn_ntohs(src)>>10) == (dn_ntohs((decnet_address))>>10)) {
413			if (!dn_db->router) {
414				dn_db->router = neigh_clone(neigh);
415			} else {
416				if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
417					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
418			}
419		}
420		write_unlock(&neigh->lock);
421		neigh_release(neigh);
422	}
423
424	kfree_skb(skb);
425	return 0;
426}
427
428/*
429 * Endnode hello message received
430 */
431int dn_neigh_endnode_hello(struct sk_buff *skb)
432{
433	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
434	struct neighbour *neigh;
435	struct dn_neigh *dn;
436	__le16 src;
437
438	src = dn_eth2dn(msg->id);
439
440	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
441
442	dn = (struct dn_neigh *)neigh;
443
444	if (neigh) {
445		write_lock(&neigh->lock);
446
447		neigh->used = jiffies;
448
449		if (!(neigh->nud_state & NUD_PERMANENT)) {
450			neigh->updated = jiffies;
451
452			if (neigh->dev->type == ARPHRD_ETHER)
453				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
454			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
455			dn->blksize  = dn_ntohs(msg->blksize);
456			dn->priority = 0;
457		}
458
459		write_unlock(&neigh->lock);
460		neigh_release(neigh);
461	}
462
463	kfree_skb(skb);
464	return 0;
465}
466
467static char *dn_find_slot(char *base, int max, int priority)
468{
469	int i;
470	unsigned char *min = NULL;
471
472	base += 6; /* skip first id */
473
474	for(i = 0; i < max; i++) {
475		if (!min || (*base < *min))
476			min = base;
477		base += 7; /* find next priority */
478	}
479
480	if (!min)
481		return NULL;
482
483	return (*min < priority) ? (min - 6) : NULL;
484}
485
486struct elist_cb_state {
487	struct net_device *dev;
488	unsigned char *ptr;
489	unsigned char *rs;
490	int t, n;
491};
492
493static void neigh_elist_cb(struct neighbour *neigh, void *_info)
494{
495	struct elist_cb_state *s = _info;
496	struct dn_neigh *dn;
497
498	if (neigh->dev != s->dev)
499		return;
500
501	dn = (struct dn_neigh *) neigh;
502	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
503		return;
504
505	if (s->t == s->n)
506		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
507	else
508		s->t++;
509	if (s->rs == NULL)
510		return;
511
512	dn_dn2eth(s->rs, dn->addr);
513	s->rs += 6;
514	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
515	*(s->rs) |= dn->priority;
516	s->rs++;
517}
518
519int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
520{
521	struct elist_cb_state state;
522
523	state.dev = dev;
524	state.t = 0;
525	state.n = n;
526	state.ptr = ptr;
527	state.rs = ptr;
528
529	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
530
531	return state.t;
532}
533
534
535#ifdef CONFIG_PROC_FS
536
537static inline void dn_neigh_format_entry(struct seq_file *seq,
538					 struct neighbour *n)
539{
540	struct dn_neigh *dn = (struct dn_neigh *) n;
541	char buf[DN_ASCBUF_LEN];
542
543	read_lock(&n->lock);
544	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
545		   dn_addr2asc(dn_ntohs(dn->addr), buf),
546		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
547		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
548		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
549		   dn->n.nud_state,
550		   atomic_read(&dn->n.refcnt),
551		   dn->blksize,
552		   (dn->n.dev) ? dn->n.dev->name : "?");
553	read_unlock(&n->lock);
554}
555
556static int dn_neigh_seq_show(struct seq_file *seq, void *v)
557{
558	if (v == SEQ_START_TOKEN) {
559		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
560	} else {
561		dn_neigh_format_entry(seq, v);
562	}
563
564	return 0;
565}
566
567static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
568{
569	return neigh_seq_start(seq, pos, &dn_neigh_table,
570			       NEIGH_SEQ_NEIGH_ONLY);
571}
572
573static struct seq_operations dn_neigh_seq_ops = {
574	.start = dn_neigh_seq_start,
575	.next  = neigh_seq_next,
576	.stop  = neigh_seq_stop,
577	.show  = dn_neigh_seq_show,
578};
579
580static int dn_neigh_seq_open(struct inode *inode, struct file *file)
581{
582	struct seq_file *seq;
583	int rc = -ENOMEM;
584	struct neigh_seq_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
585
586	if (!s)
587		goto out;
588
589	memset(s, 0, sizeof(*s));
590	rc = seq_open(file, &dn_neigh_seq_ops);
591	if (rc)
592		goto out_kfree;
593
594	seq          = file->private_data;
595	seq->private = s;
596	memset(s, 0, sizeof(*s));
597out:
598	return rc;
599out_kfree:
600	kfree(s);
601	goto out;
602}
603
604static struct file_operations dn_neigh_seq_fops = {
605	.owner		= THIS_MODULE,
606	.open		= dn_neigh_seq_open,
607	.read		= seq_read,
608	.llseek		= seq_lseek,
609	.release	= seq_release_private,
610};
611
612#endif
613
614void __init dn_neigh_init(void)
615{
616	neigh_table_init(&dn_neigh_table);
617	proc_net_fops_create("decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
618}
619
620void __exit dn_neigh_cleanup(void)
621{
622	proc_net_remove("decnet_neigh");
623	neigh_table_clear(&dn_neigh_table);
624}
625