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/net.h>
28#include <linux/module.h>
29#include <linux/socket.h>
30#include <linux/if_arp.h>
31#include <linux/slab.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/net_namespace.h>
43#include <net/neighbour.h>
44#include <net/dst.h>
45#include <net/flow.h>
46#include <net/dn.h>
47#include <net/dn_dev.h>
48#include <net/dn_neigh.h>
49#include <net/dn_route.h>
50
51static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev);
52static int dn_neigh_construct(struct neighbour *);
53static void dn_long_error_report(struct neighbour *, struct sk_buff *);
54static void dn_short_error_report(struct neighbour *, struct sk_buff *);
55static int dn_long_output(struct sk_buff *);
56static int dn_short_output(struct sk_buff *);
57static int dn_phase3_output(struct sk_buff *);
58
59
60/*
61 * For talking to broadcast devices: Ethernet & PPP
62 */
63static const struct neigh_ops dn_long_ops = {
64	.family =		AF_DECnet,
65	.error_report =		dn_long_error_report,
66	.output =		dn_long_output,
67	.connected_output =	dn_long_output,
68	.hh_output =		dev_queue_xmit,
69	.queue_xmit =		dev_queue_xmit,
70};
71
72/*
73 * For talking to pointopoint and multidrop devices: DDCMP and X.25
74 */
75static const struct neigh_ops dn_short_ops = {
76	.family =		AF_DECnet,
77	.error_report =		dn_short_error_report,
78	.output =		dn_short_output,
79	.connected_output =	dn_short_output,
80	.hh_output =		dev_queue_xmit,
81	.queue_xmit =		dev_queue_xmit,
82};
83
84/*
85 * For talking to DECnet phase III nodes
86 */
87static const struct neigh_ops dn_phase3_ops = {
88	.family =		AF_DECnet,
89	.error_report =		dn_short_error_report, /* Can use short version here */
90	.output =		dn_phase3_output,
91	.connected_output =	dn_phase3_output,
92	.hh_output =		dev_queue_xmit,
93	.queue_xmit =		dev_queue_xmit
94};
95
96struct neigh_table dn_neigh_table = {
97	.family =			PF_DECnet,
98	.entry_size =			sizeof(struct dn_neigh),
99	.key_len =			sizeof(__le16),
100	.hash =				dn_neigh_hash,
101	.constructor =			dn_neigh_construct,
102	.id =				"dn_neigh_cache",
103	.parms ={
104		.tbl =			&dn_neigh_table,
105		.base_reachable_time =	30 * HZ,
106		.retrans_time =	1 * HZ,
107		.gc_staletime =	60 * HZ,
108		.reachable_time =		30 * HZ,
109		.delay_probe_time =	5 * HZ,
110		.queue_len =		3,
111		.ucast_probes =	0,
112		.app_probes =		0,
113		.mcast_probes =	0,
114		.anycast_delay =	0,
115		.proxy_delay =		0,
116		.proxy_qlen =		0,
117		.locktime =		1 * HZ,
118	},
119	.gc_interval =			30 * HZ,
120	.gc_thresh1 =			128,
121	.gc_thresh2 =			512,
122	.gc_thresh3 =			1024,
123};
124
125static u32 dn_neigh_hash(const void *pkey, const struct net_device *dev)
126{
127	return jhash_2words(*(__u16 *)pkey, 0, dn_neigh_table.hash_rnd);
128}
129
130static int dn_neigh_construct(struct neighbour *neigh)
131{
132	struct net_device *dev = neigh->dev;
133	struct dn_neigh *dn = (struct dn_neigh *)neigh;
134	struct dn_dev *dn_db;
135	struct neigh_parms *parms;
136
137	rcu_read_lock();
138	dn_db = rcu_dereference(dev->dn_ptr);
139	if (dn_db == NULL) {
140		rcu_read_unlock();
141		return -EINVAL;
142	}
143
144	parms = dn_db->neigh_parms;
145	if (!parms) {
146		rcu_read_unlock();
147		return -EINVAL;
148	}
149
150	__neigh_parms_put(neigh->parms);
151	neigh->parms = neigh_parms_clone(parms);
152
153	if (dn_db->use_long)
154		neigh->ops = &dn_long_ops;
155	else
156		neigh->ops = &dn_short_ops;
157	rcu_read_unlock();
158
159	if (dn->flags & DN_NDFLAG_P3)
160		neigh->ops = &dn_phase3_ops;
161
162	neigh->nud_state = NUD_NOARP;
163	neigh->output = neigh->ops->connected_output;
164
165	if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
166		memcpy(neigh->ha, dev->broadcast, dev->addr_len);
167	else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
168		dn_dn2eth(neigh->ha, dn->addr);
169	else {
170		if (net_ratelimit())
171			printk(KERN_DEBUG "Trying to create neigh for hw %d\n",  dev->type);
172		return -EINVAL;
173	}
174
175	/*
176	 * Make an estimate of the remote block size by assuming that its
177	 * two less then the device mtu, which it true for ethernet (and
178	 * other things which support long format headers) since there is
179	 * an extra length field (of 16 bits) which isn't part of the
180	 * ethernet headers and which the DECnet specs won't admit is part
181	 * of the DECnet routing headers either.
182	 *
183	 * If we over estimate here its no big deal, the NSP negotiations
184	 * will prevent us from sending packets which are too large for the
185	 * remote node to handle. In any case this figure is normally updated
186	 * by a hello message in most cases.
187	 */
188	dn->blksize = dev->mtu - 2;
189
190	return 0;
191}
192
193static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
194{
195	printk(KERN_DEBUG "dn_long_error_report: called\n");
196	kfree_skb(skb);
197}
198
199
200static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
201{
202	printk(KERN_DEBUG "dn_short_error_report: called\n");
203	kfree_skb(skb);
204}
205
206static int dn_neigh_output_packet(struct sk_buff *skb)
207{
208	struct dst_entry *dst = skb_dst(skb);
209	struct dn_route *rt = (struct dn_route *)dst;
210	struct neighbour *neigh = dst->neighbour;
211	struct net_device *dev = neigh->dev;
212	char mac_addr[ETH_ALEN];
213
214	dn_dn2eth(mac_addr, rt->rt_local_src);
215	if (dev_hard_header(skb, dev, ntohs(skb->protocol), neigh->ha,
216			    mac_addr, skb->len) >= 0)
217		return neigh->ops->queue_xmit(skb);
218
219	if (net_ratelimit())
220		printk(KERN_DEBUG "dn_neigh_output_packet: oops, can't send packet\n");
221
222	kfree_skb(skb);
223	return -EINVAL;
224}
225
226static int dn_long_output(struct sk_buff *skb)
227{
228	struct dst_entry *dst = skb_dst(skb);
229	struct neighbour *neigh = dst->neighbour;
230	struct net_device *dev = neigh->dev;
231	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
232	unsigned char *data;
233	struct dn_long_packet *lp;
234	struct dn_skb_cb *cb = DN_SKB_CB(skb);
235
236
237	if (skb_headroom(skb) < headroom) {
238		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
239		if (skb2 == NULL) {
240			if (net_ratelimit())
241				printk(KERN_CRIT "dn_long_output: no memory\n");
242			kfree_skb(skb);
243			return -ENOBUFS;
244		}
245		kfree_skb(skb);
246		skb = skb2;
247		if (net_ratelimit())
248			printk(KERN_INFO "dn_long_output: Increasing headroom\n");
249	}
250
251	data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
252	lp = (struct dn_long_packet *)(data+3);
253
254	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
255	*(data + 2) = 1 | DN_RT_F_PF; /* Padding */
256
257	lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
258	lp->d_area   = lp->d_subarea = 0;
259	dn_dn2eth(lp->d_id, cb->dst);
260	lp->s_area   = lp->s_subarea = 0;
261	dn_dn2eth(lp->s_id, cb->src);
262	lp->nl2      = 0;
263	lp->visit_ct = cb->hops & 0x3f;
264	lp->s_class  = 0;
265	lp->pt       = 0;
266
267	skb_reset_network_header(skb);
268
269	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
270		       neigh->dev, dn_neigh_output_packet);
271}
272
273static int dn_short_output(struct sk_buff *skb)
274{
275	struct dst_entry *dst = skb_dst(skb);
276	struct neighbour *neigh = dst->neighbour;
277	struct net_device *dev = neigh->dev;
278	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
279	struct dn_short_packet *sp;
280	unsigned char *data;
281	struct dn_skb_cb *cb = DN_SKB_CB(skb);
282
283
284	if (skb_headroom(skb) < headroom) {
285		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
286		if (skb2 == NULL) {
287			if (net_ratelimit())
288				printk(KERN_CRIT "dn_short_output: no memory\n");
289			kfree_skb(skb);
290			return -ENOBUFS;
291		}
292		kfree_skb(skb);
293		skb = skb2;
294		if (net_ratelimit())
295			printk(KERN_INFO "dn_short_output: Increasing headroom\n");
296	}
297
298	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
299	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
300	sp = (struct dn_short_packet *)(data+2);
301
302	sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
303	sp->dstnode    = cb->dst;
304	sp->srcnode    = cb->src;
305	sp->forward    = cb->hops & 0x3f;
306
307	skb_reset_network_header(skb);
308
309	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
310		       neigh->dev, dn_neigh_output_packet);
311}
312
313/*
314 * Phase 3 output is the same is short output, execpt that
315 * it clears the area bits before transmission.
316 */
317static int dn_phase3_output(struct sk_buff *skb)
318{
319	struct dst_entry *dst = skb_dst(skb);
320	struct neighbour *neigh = dst->neighbour;
321	struct net_device *dev = neigh->dev;
322	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
323	struct dn_short_packet *sp;
324	unsigned char *data;
325	struct dn_skb_cb *cb = DN_SKB_CB(skb);
326
327	if (skb_headroom(skb) < headroom) {
328		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
329		if (skb2 == NULL) {
330			if (net_ratelimit())
331				printk(KERN_CRIT "dn_phase3_output: no memory\n");
332			kfree_skb(skb);
333			return -ENOBUFS;
334		}
335		kfree_skb(skb);
336		skb = skb2;
337		if (net_ratelimit())
338			printk(KERN_INFO "dn_phase3_output: Increasing headroom\n");
339	}
340
341	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
342	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
343	sp = (struct dn_short_packet *)(data + 2);
344
345	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
346	sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
347	sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
348	sp->forward  = cb->hops & 0x3f;
349
350	skb_reset_network_header(skb);
351
352	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
353		       neigh->dev, dn_neigh_output_packet);
354}
355
356/*
357 * Unfortunately, the neighbour code uses the device in its hash
358 * function, so we don't get any advantage from it. This function
359 * basically does a neigh_lookup(), but without comparing the device
360 * field. This is required for the On-Ethernet cache
361 */
362
363/*
364 * Pointopoint link receives a hello message
365 */
366void dn_neigh_pointopoint_hello(struct sk_buff *skb)
367{
368	kfree_skb(skb);
369}
370
371/*
372 * Ethernet router hello message received
373 */
374int dn_neigh_router_hello(struct sk_buff *skb)
375{
376	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
377
378	struct neighbour *neigh;
379	struct dn_neigh *dn;
380	struct dn_dev *dn_db;
381	__le16 src;
382
383	src = dn_eth2dn(msg->id);
384
385	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
386
387	dn = (struct dn_neigh *)neigh;
388
389	if (neigh) {
390		write_lock(&neigh->lock);
391
392		neigh->used = jiffies;
393		dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
394
395		if (!(neigh->nud_state & NUD_PERMANENT)) {
396			neigh->updated = jiffies;
397
398			if (neigh->dev->type == ARPHRD_ETHER)
399				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
400
401			dn->blksize  = le16_to_cpu(msg->blksize);
402			dn->priority = msg->priority;
403
404			dn->flags &= ~DN_NDFLAG_P3;
405
406			switch(msg->iinfo & DN_RT_INFO_TYPE) {
407				case DN_RT_INFO_L1RT:
408					dn->flags &=~DN_NDFLAG_R2;
409					dn->flags |= DN_NDFLAG_R1;
410					break;
411				case DN_RT_INFO_L2RT:
412					dn->flags |= DN_NDFLAG_R2;
413			}
414		}
415
416		/* Only use routers in our area */
417		if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
418			if (!dn_db->router) {
419				dn_db->router = neigh_clone(neigh);
420			} else {
421				if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
422					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
423			}
424		}
425		write_unlock(&neigh->lock);
426		neigh_release(neigh);
427	}
428
429	kfree_skb(skb);
430	return 0;
431}
432
433/*
434 * Endnode hello message received
435 */
436int dn_neigh_endnode_hello(struct sk_buff *skb)
437{
438	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
439	struct neighbour *neigh;
440	struct dn_neigh *dn;
441	__le16 src;
442
443	src = dn_eth2dn(msg->id);
444
445	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
446
447	dn = (struct dn_neigh *)neigh;
448
449	if (neigh) {
450		write_lock(&neigh->lock);
451
452		neigh->used = jiffies;
453
454		if (!(neigh->nud_state & NUD_PERMANENT)) {
455			neigh->updated = jiffies;
456
457			if (neigh->dev->type == ARPHRD_ETHER)
458				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
459			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
460			dn->blksize  = le16_to_cpu(msg->blksize);
461			dn->priority = 0;
462		}
463
464		write_unlock(&neigh->lock);
465		neigh_release(neigh);
466	}
467
468	kfree_skb(skb);
469	return 0;
470}
471
472static char *dn_find_slot(char *base, int max, int priority)
473{
474	int i;
475	unsigned char *min = NULL;
476
477	base += 6; /* skip first id */
478
479	for(i = 0; i < max; i++) {
480		if (!min || (*base < *min))
481			min = base;
482		base += 7; /* find next priority */
483	}
484
485	if (!min)
486		return NULL;
487
488	return (*min < priority) ? (min - 6) : NULL;
489}
490
491struct elist_cb_state {
492	struct net_device *dev;
493	unsigned char *ptr;
494	unsigned char *rs;
495	int t, n;
496};
497
498static void neigh_elist_cb(struct neighbour *neigh, void *_info)
499{
500	struct elist_cb_state *s = _info;
501	struct dn_neigh *dn;
502
503	if (neigh->dev != s->dev)
504		return;
505
506	dn = (struct dn_neigh *) neigh;
507	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
508		return;
509
510	if (s->t == s->n)
511		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
512	else
513		s->t++;
514	if (s->rs == NULL)
515		return;
516
517	dn_dn2eth(s->rs, dn->addr);
518	s->rs += 6;
519	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
520	*(s->rs) |= dn->priority;
521	s->rs++;
522}
523
524int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
525{
526	struct elist_cb_state state;
527
528	state.dev = dev;
529	state.t = 0;
530	state.n = n;
531	state.ptr = ptr;
532	state.rs = ptr;
533
534	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
535
536	return state.t;
537}
538
539
540#ifdef CONFIG_PROC_FS
541
542static inline void dn_neigh_format_entry(struct seq_file *seq,
543					 struct neighbour *n)
544{
545	struct dn_neigh *dn = (struct dn_neigh *) n;
546	char buf[DN_ASCBUF_LEN];
547
548	read_lock(&n->lock);
549	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
550		   dn_addr2asc(le16_to_cpu(dn->addr), buf),
551		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
552		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
553		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
554		   dn->n.nud_state,
555		   atomic_read(&dn->n.refcnt),
556		   dn->blksize,
557		   (dn->n.dev) ? dn->n.dev->name : "?");
558	read_unlock(&n->lock);
559}
560
561static int dn_neigh_seq_show(struct seq_file *seq, void *v)
562{
563	if (v == SEQ_START_TOKEN) {
564		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
565	} else {
566		dn_neigh_format_entry(seq, v);
567	}
568
569	return 0;
570}
571
572static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
573{
574	return neigh_seq_start(seq, pos, &dn_neigh_table,
575			       NEIGH_SEQ_NEIGH_ONLY);
576}
577
578static const struct seq_operations dn_neigh_seq_ops = {
579	.start = dn_neigh_seq_start,
580	.next  = neigh_seq_next,
581	.stop  = neigh_seq_stop,
582	.show  = dn_neigh_seq_show,
583};
584
585static int dn_neigh_seq_open(struct inode *inode, struct file *file)
586{
587	return seq_open_net(inode, file, &dn_neigh_seq_ops,
588			    sizeof(struct neigh_seq_state));
589}
590
591static const struct file_operations dn_neigh_seq_fops = {
592	.owner		= THIS_MODULE,
593	.open		= dn_neigh_seq_open,
594	.read		= seq_read,
595	.llseek		= seq_lseek,
596	.release	= seq_release_net,
597};
598
599#endif
600
601void __init dn_neigh_init(void)
602{
603	neigh_table_init(&dn_neigh_table);
604	proc_net_fops_create(&init_net, "decnet_neigh", S_IRUGO, &dn_neigh_seq_fops);
605}
606
607void __exit dn_neigh_cleanup(void)
608{
609	proc_net_remove(&init_net, "decnet_neigh");
610	neigh_table_clear(&dn_neigh_table);
611}
612