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 <linux/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 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 neighbour *, struct sk_buff *);
55static int dn_short_output(struct neighbour *, struct sk_buff *);
56static int dn_phase3_output(struct neighbour *, struct sk_buff *);
57
58
59/*
60 * For talking to broadcast devices: Ethernet & PPP
61 */
62static const 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};
68
69/*
70 * For talking to pointopoint and multidrop devices: DDCMP and X.25
71 */
72static const struct neigh_ops dn_short_ops = {
73	.family =		AF_DECnet,
74	.error_report =		dn_short_error_report,
75	.output =		dn_short_output,
76	.connected_output =	dn_short_output,
77};
78
79/*
80 * For talking to DECnet phase III nodes
81 */
82static const struct neigh_ops dn_phase3_ops = {
83	.family =		AF_DECnet,
84	.error_report =		dn_short_error_report, /* Can use short version here */
85	.output =		dn_phase3_output,
86	.connected_output =	dn_phase3_output,
87};
88
89static u32 dn_neigh_hash(const void *pkey,
90			 const struct net_device *dev,
91			 __u32 *hash_rnd)
92{
93	return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
94}
95
96struct neigh_table dn_neigh_table = {
97	.family =			PF_DECnet,
98	.entry_size =			NEIGH_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_bytes =	64*1024,
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 int dn_neigh_construct(struct neighbour *neigh)
126{
127	struct net_device *dev = neigh->dev;
128	struct dn_neigh *dn = (struct dn_neigh *)neigh;
129	struct dn_dev *dn_db;
130	struct neigh_parms *parms;
131
132	rcu_read_lock();
133	dn_db = rcu_dereference(dev->dn_ptr);
134	if (dn_db == NULL) {
135		rcu_read_unlock();
136		return -EINVAL;
137	}
138
139	parms = dn_db->neigh_parms;
140	if (!parms) {
141		rcu_read_unlock();
142		return -EINVAL;
143	}
144
145	__neigh_parms_put(neigh->parms);
146	neigh->parms = neigh_parms_clone(parms);
147
148	if (dn_db->use_long)
149		neigh->ops = &dn_long_ops;
150	else
151		neigh->ops = &dn_short_ops;
152	rcu_read_unlock();
153
154	if (dn->flags & DN_NDFLAG_P3)
155		neigh->ops = &dn_phase3_ops;
156
157	neigh->nud_state = NUD_NOARP;
158	neigh->output = neigh->ops->connected_output;
159
160	if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
161		memcpy(neigh->ha, dev->broadcast, dev->addr_len);
162	else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
163		dn_dn2eth(neigh->ha, dn->addr);
164	else {
165		net_dbg_ratelimited("Trying to create neigh for hw %d\n",
166				    dev->type);
167		return -EINVAL;
168	}
169
170	/*
171	 * Make an estimate of the remote block size by assuming that its
172	 * two less then the device mtu, which it true for ethernet (and
173	 * other things which support long format headers) since there is
174	 * an extra length field (of 16 bits) which isn't part of the
175	 * ethernet headers and which the DECnet specs won't admit is part
176	 * of the DECnet routing headers either.
177	 *
178	 * If we over estimate here its no big deal, the NSP negotiations
179	 * will prevent us from sending packets which are too large for the
180	 * remote node to handle. In any case this figure is normally updated
181	 * by a hello message in most cases.
182	 */
183	dn->blksize = dev->mtu - 2;
184
185	return 0;
186}
187
188static void dn_long_error_report(struct neighbour *neigh, struct sk_buff *skb)
189{
190	printk(KERN_DEBUG "dn_long_error_report: called\n");
191	kfree_skb(skb);
192}
193
194
195static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
196{
197	printk(KERN_DEBUG "dn_short_error_report: called\n");
198	kfree_skb(skb);
199}
200
201static int dn_neigh_output_packet(struct sk_buff *skb)
202{
203	struct dst_entry *dst = skb_dst(skb);
204	struct dn_route *rt = (struct dn_route *)dst;
205	struct neighbour *neigh = rt->n;
206	struct net_device *dev = neigh->dev;
207	char mac_addr[ETH_ALEN];
208	unsigned int seq;
209	int err;
210
211	dn_dn2eth(mac_addr, rt->rt_local_src);
212	do {
213		seq = read_seqbegin(&neigh->ha_lock);
214		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
215				      neigh->ha, mac_addr, skb->len);
216	} while (read_seqretry(&neigh->ha_lock, seq));
217
218	if (err >= 0)
219		err = dev_queue_xmit(skb);
220	else {
221		kfree_skb(skb);
222		err = -EINVAL;
223	}
224	return err;
225}
226
227static int dn_long_output(struct neighbour *neigh, struct sk_buff *skb)
228{
229	struct net_device *dev = neigh->dev;
230	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
231	unsigned char *data;
232	struct dn_long_packet *lp;
233	struct dn_skb_cb *cb = DN_SKB_CB(skb);
234
235
236	if (skb_headroom(skb) < headroom) {
237		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
238		if (skb2 == NULL) {
239			net_crit_ratelimited("dn_long_output: no memory\n");
240			kfree_skb(skb);
241			return -ENOBUFS;
242		}
243		consume_skb(skb);
244		skb = skb2;
245		net_info_ratelimited("dn_long_output: Increasing headroom\n");
246	}
247
248	data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
249	lp = (struct dn_long_packet *)(data+3);
250
251	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
252	*(data + 2) = 1 | DN_RT_F_PF; /* Padding */
253
254	lp->msgflg   = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
255	lp->d_area   = lp->d_subarea = 0;
256	dn_dn2eth(lp->d_id, cb->dst);
257	lp->s_area   = lp->s_subarea = 0;
258	dn_dn2eth(lp->s_id, cb->src);
259	lp->nl2      = 0;
260	lp->visit_ct = cb->hops & 0x3f;
261	lp->s_class  = 0;
262	lp->pt       = 0;
263
264	skb_reset_network_header(skb);
265
266	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
267		       neigh->dev, dn_neigh_output_packet);
268}
269
270static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
271{
272	struct net_device *dev = neigh->dev;
273	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
274	struct dn_short_packet *sp;
275	unsigned char *data;
276	struct dn_skb_cb *cb = DN_SKB_CB(skb);
277
278
279	if (skb_headroom(skb) < headroom) {
280		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
281		if (skb2 == NULL) {
282			net_crit_ratelimited("dn_short_output: no memory\n");
283			kfree_skb(skb);
284			return -ENOBUFS;
285		}
286		consume_skb(skb);
287		skb = skb2;
288		net_info_ratelimited("dn_short_output: Increasing headroom\n");
289	}
290
291	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
292	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
293	sp = (struct dn_short_packet *)(data+2);
294
295	sp->msgflg     = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
296	sp->dstnode    = cb->dst;
297	sp->srcnode    = cb->src;
298	sp->forward    = cb->hops & 0x3f;
299
300	skb_reset_network_header(skb);
301
302	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
303		       neigh->dev, dn_neigh_output_packet);
304}
305
306/*
307 * Phase 3 output is the same is short output, execpt that
308 * it clears the area bits before transmission.
309 */
310static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
311{
312	struct net_device *dev = neigh->dev;
313	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
314	struct dn_short_packet *sp;
315	unsigned char *data;
316	struct dn_skb_cb *cb = DN_SKB_CB(skb);
317
318	if (skb_headroom(skb) < headroom) {
319		struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
320		if (skb2 == NULL) {
321			net_crit_ratelimited("dn_phase3_output: no memory\n");
322			kfree_skb(skb);
323			return -ENOBUFS;
324		}
325		consume_skb(skb);
326		skb = skb2;
327		net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
328	}
329
330	data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
331	*((__le16 *)data) = cpu_to_le16(skb->len - 2);
332	sp = (struct dn_short_packet *)(data + 2);
333
334	sp->msgflg   = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
335	sp->dstnode  = cb->dst & cpu_to_le16(0x03ff);
336	sp->srcnode  = cb->src & cpu_to_le16(0x03ff);
337	sp->forward  = cb->hops & 0x3f;
338
339	skb_reset_network_header(skb);
340
341	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
342		       neigh->dev, dn_neigh_output_packet);
343}
344
345/*
346 * Unfortunately, the neighbour code uses the device in its hash
347 * function, so we don't get any advantage from it. This function
348 * basically does a neigh_lookup(), but without comparing the device
349 * field. This is required for the On-Ethernet cache
350 */
351
352/*
353 * Pointopoint link receives a hello message
354 */
355void dn_neigh_pointopoint_hello(struct sk_buff *skb)
356{
357	kfree_skb(skb);
358}
359
360/*
361 * Ethernet router hello message received
362 */
363int dn_neigh_router_hello(struct sk_buff *skb)
364{
365	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
366
367	struct neighbour *neigh;
368	struct dn_neigh *dn;
369	struct dn_dev *dn_db;
370	__le16 src;
371
372	src = dn_eth2dn(msg->id);
373
374	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
375
376	dn = (struct dn_neigh *)neigh;
377
378	if (neigh) {
379		write_lock(&neigh->lock);
380
381		neigh->used = jiffies;
382		dn_db = rcu_dereference(neigh->dev->dn_ptr);
383
384		if (!(neigh->nud_state & NUD_PERMANENT)) {
385			neigh->updated = jiffies;
386
387			if (neigh->dev->type == ARPHRD_ETHER)
388				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
389
390			dn->blksize  = le16_to_cpu(msg->blksize);
391			dn->priority = msg->priority;
392
393			dn->flags &= ~DN_NDFLAG_P3;
394
395			switch (msg->iinfo & DN_RT_INFO_TYPE) {
396			case DN_RT_INFO_L1RT:
397				dn->flags &=~DN_NDFLAG_R2;
398				dn->flags |= DN_NDFLAG_R1;
399				break;
400			case DN_RT_INFO_L2RT:
401				dn->flags |= DN_NDFLAG_R2;
402			}
403		}
404
405		/* Only use routers in our area */
406		if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
407			if (!dn_db->router) {
408				dn_db->router = neigh_clone(neigh);
409			} else {
410				if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
411					neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
412			}
413		}
414		write_unlock(&neigh->lock);
415		neigh_release(neigh);
416	}
417
418	kfree_skb(skb);
419	return 0;
420}
421
422/*
423 * Endnode hello message received
424 */
425int dn_neigh_endnode_hello(struct sk_buff *skb)
426{
427	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
428	struct neighbour *neigh;
429	struct dn_neigh *dn;
430	__le16 src;
431
432	src = dn_eth2dn(msg->id);
433
434	neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
435
436	dn = (struct dn_neigh *)neigh;
437
438	if (neigh) {
439		write_lock(&neigh->lock);
440
441		neigh->used = jiffies;
442
443		if (!(neigh->nud_state & NUD_PERMANENT)) {
444			neigh->updated = jiffies;
445
446			if (neigh->dev->type == ARPHRD_ETHER)
447				memcpy(neigh->ha, &eth_hdr(skb)->h_source, ETH_ALEN);
448			dn->flags   &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
449			dn->blksize  = le16_to_cpu(msg->blksize);
450			dn->priority = 0;
451		}
452
453		write_unlock(&neigh->lock);
454		neigh_release(neigh);
455	}
456
457	kfree_skb(skb);
458	return 0;
459}
460
461static char *dn_find_slot(char *base, int max, int priority)
462{
463	int i;
464	unsigned char *min = NULL;
465
466	base += 6; /* skip first id */
467
468	for(i = 0; i < max; i++) {
469		if (!min || (*base < *min))
470			min = base;
471		base += 7; /* find next priority */
472	}
473
474	if (!min)
475		return NULL;
476
477	return (*min < priority) ? (min - 6) : NULL;
478}
479
480struct elist_cb_state {
481	struct net_device *dev;
482	unsigned char *ptr;
483	unsigned char *rs;
484	int t, n;
485};
486
487static void neigh_elist_cb(struct neighbour *neigh, void *_info)
488{
489	struct elist_cb_state *s = _info;
490	struct dn_neigh *dn;
491
492	if (neigh->dev != s->dev)
493		return;
494
495	dn = (struct dn_neigh *) neigh;
496	if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
497		return;
498
499	if (s->t == s->n)
500		s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
501	else
502		s->t++;
503	if (s->rs == NULL)
504		return;
505
506	dn_dn2eth(s->rs, dn->addr);
507	s->rs += 6;
508	*(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
509	*(s->rs) |= dn->priority;
510	s->rs++;
511}
512
513int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
514{
515	struct elist_cb_state state;
516
517	state.dev = dev;
518	state.t = 0;
519	state.n = n;
520	state.ptr = ptr;
521	state.rs = ptr;
522
523	neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
524
525	return state.t;
526}
527
528
529#ifdef CONFIG_PROC_FS
530
531static inline void dn_neigh_format_entry(struct seq_file *seq,
532					 struct neighbour *n)
533{
534	struct dn_neigh *dn = (struct dn_neigh *) n;
535	char buf[DN_ASCBUF_LEN];
536
537	read_lock(&n->lock);
538	seq_printf(seq, "%-7s %s%s%s   %02x    %02d  %07ld %-8s\n",
539		   dn_addr2asc(le16_to_cpu(dn->addr), buf),
540		   (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
541		   (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
542		   (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
543		   dn->n.nud_state,
544		   atomic_read(&dn->n.refcnt),
545		   dn->blksize,
546		   (dn->n.dev) ? dn->n.dev->name : "?");
547	read_unlock(&n->lock);
548}
549
550static int dn_neigh_seq_show(struct seq_file *seq, void *v)
551{
552	if (v == SEQ_START_TOKEN) {
553		seq_puts(seq, "Addr    Flags State Use Blksize Dev\n");
554	} else {
555		dn_neigh_format_entry(seq, v);
556	}
557
558	return 0;
559}
560
561static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
562{
563	return neigh_seq_start(seq, pos, &dn_neigh_table,
564			       NEIGH_SEQ_NEIGH_ONLY);
565}
566
567static const struct seq_operations dn_neigh_seq_ops = {
568	.start = dn_neigh_seq_start,
569	.next  = neigh_seq_next,
570	.stop  = neigh_seq_stop,
571	.show  = dn_neigh_seq_show,
572};
573
574static int dn_neigh_seq_open(struct inode *inode, struct file *file)
575{
576	return seq_open_net(inode, file, &dn_neigh_seq_ops,
577			    sizeof(struct neigh_seq_state));
578}
579
580static const struct file_operations dn_neigh_seq_fops = {
581	.owner		= THIS_MODULE,
582	.open		= dn_neigh_seq_open,
583	.read		= seq_read,
584	.llseek		= seq_lseek,
585	.release	= seq_release_net,
586};
587
588#endif
589
590void __init dn_neigh_init(void)
591{
592	neigh_table_init(&dn_neigh_table);
593	proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
594		    &dn_neigh_seq_fops);
595}
596
597void __exit dn_neigh_cleanup(void)
598{
599	remove_proc_entry("decnet_neigh", init_net.proc_net);
600	neigh_table_clear(&dn_neigh_table);
601}
602