1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * DECnet An implementation of the DECnet protocol suite for the LINUX
4 * operating system. DECnet is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * DECnet Neighbour Functions (Adjacency Database and
8 * On-Ethernet Cache)
9 *
10 * Author: Steve Whitehouse <SteveW@ACM.org>
11 *
12 *
13 * Changes:
14 * Steve Whitehouse : Fixed router listing routine
15 * Steve Whitehouse : Added error_report functions
16 * Steve Whitehouse : Added default router detection
17 * Steve Whitehouse : Hop counts in outgoing messages
18 * Steve Whitehouse : Fixed src/dst in outgoing messages so
19 * forwarding now stands a good chance of
20 * working.
21 * Steve Whitehouse : Fixed neighbour states (for now anyway).
22 * Steve Whitehouse : Made error_report functions dummies. This
23 * is not the right place to return skbs.
24 * Steve Whitehouse : Convert to seq_file
25 *
26 */
27
28 #include <linux/net.h>
29 #include <linux/module.h>
30 #include <linux/socket.h>
31 #include <linux/if_arp.h>
32 #include <linux/slab.h>
33 #include <linux/if_ether.h>
34 #include <linux/init.h>
35 #include <linux/proc_fs.h>
36 #include <linux/string.h>
37 #include <linux/netfilter_decnet.h>
38 #include <linux/spinlock.h>
39 #include <linux/seq_file.h>
40 #include <linux/rcupdate.h>
41 #include <linux/jhash.h>
42 #include <linux/atomic.h>
43 #include <net/net_namespace.h>
44 #include <net/neighbour.h>
45 #include <net/dst.h>
46 #include <net/flow.h>
47 #include <net/dn.h>
48 #include <net/dn_dev.h>
49 #include <net/dn_neigh.h>
50 #include <net/dn_route.h>
51
52 static int dn_neigh_construct(struct neighbour *);
53 static void dn_neigh_error_report(struct neighbour *, struct sk_buff *);
54 static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb);
55
56 /*
57 * Operations for adding the link layer header.
58 */
59 static const struct neigh_ops dn_neigh_ops = {
60 .family = AF_DECnet,
61 .error_report = dn_neigh_error_report,
62 .output = dn_neigh_output,
63 .connected_output = dn_neigh_output,
64 };
65
dn_neigh_hash(const void * pkey,const struct net_device * dev,__u32 * hash_rnd)66 static u32 dn_neigh_hash(const void *pkey,
67 const struct net_device *dev,
68 __u32 *hash_rnd)
69 {
70 return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
71 }
72
dn_key_eq(const struct neighbour * neigh,const void * pkey)73 static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
74 {
75 return neigh_key_eq16(neigh, pkey);
76 }
77
78 struct neigh_table dn_neigh_table = {
79 .family = PF_DECnet,
80 .entry_size = NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
81 .key_len = sizeof(__le16),
82 .protocol = cpu_to_be16(ETH_P_DNA_RT),
83 .hash = dn_neigh_hash,
84 .key_eq = dn_key_eq,
85 .constructor = dn_neigh_construct,
86 .id = "dn_neigh_cache",
87 .parms ={
88 .tbl = &dn_neigh_table,
89 .reachable_time = 30 * HZ,
90 .data = {
91 [NEIGH_VAR_MCAST_PROBES] = 0,
92 [NEIGH_VAR_UCAST_PROBES] = 0,
93 [NEIGH_VAR_APP_PROBES] = 0,
94 [NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
95 [NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
96 [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
97 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
98 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
99 [NEIGH_VAR_PROXY_QLEN] = 0,
100 [NEIGH_VAR_ANYCAST_DELAY] = 0,
101 [NEIGH_VAR_PROXY_DELAY] = 0,
102 [NEIGH_VAR_LOCKTIME] = 1 * HZ,
103 },
104 },
105 .gc_interval = 30 * HZ,
106 .gc_thresh1 = 128,
107 .gc_thresh2 = 512,
108 .gc_thresh3 = 1024,
109 };
110
dn_neigh_construct(struct neighbour * neigh)111 static int dn_neigh_construct(struct neighbour *neigh)
112 {
113 struct net_device *dev = neigh->dev;
114 struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
115 struct dn_dev *dn_db;
116 struct neigh_parms *parms;
117
118 rcu_read_lock();
119 dn_db = rcu_dereference(dev->dn_ptr);
120 if (dn_db == NULL) {
121 rcu_read_unlock();
122 return -EINVAL;
123 }
124
125 parms = dn_db->neigh_parms;
126 if (!parms) {
127 rcu_read_unlock();
128 return -EINVAL;
129 }
130
131 __neigh_parms_put(neigh->parms);
132 neigh->parms = neigh_parms_clone(parms);
133 rcu_read_unlock();
134
135 neigh->ops = &dn_neigh_ops;
136 neigh->nud_state = NUD_NOARP;
137 neigh->output = neigh->ops->connected_output;
138
139 if ((dev->type == ARPHRD_IPGRE) || (dev->flags & IFF_POINTOPOINT))
140 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
141 else if ((dev->type == ARPHRD_ETHER) || (dev->type == ARPHRD_LOOPBACK))
142 dn_dn2eth(neigh->ha, dn->addr);
143 else {
144 net_dbg_ratelimited("Trying to create neigh for hw %d\n",
145 dev->type);
146 return -EINVAL;
147 }
148
149 /*
150 * Make an estimate of the remote block size by assuming that its
151 * two less then the device mtu, which it true for ethernet (and
152 * other things which support long format headers) since there is
153 * an extra length field (of 16 bits) which isn't part of the
154 * ethernet headers and which the DECnet specs won't admit is part
155 * of the DECnet routing headers either.
156 *
157 * If we over estimate here its no big deal, the NSP negotiations
158 * will prevent us from sending packets which are too large for the
159 * remote node to handle. In any case this figure is normally updated
160 * by a hello message in most cases.
161 */
162 dn->blksize = dev->mtu - 2;
163
164 return 0;
165 }
166
dn_neigh_error_report(struct neighbour * neigh,struct sk_buff * skb)167 static void dn_neigh_error_report(struct neighbour *neigh, struct sk_buff *skb)
168 {
169 printk(KERN_DEBUG "dn_neigh_error_report: called\n");
170 kfree_skb(skb);
171 }
172
dn_neigh_output(struct neighbour * neigh,struct sk_buff * skb)173 static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
174 {
175 struct dst_entry *dst = skb_dst(skb);
176 struct dn_route *rt = (struct dn_route *)dst;
177 struct net_device *dev = neigh->dev;
178 char mac_addr[ETH_ALEN];
179 unsigned int seq;
180 int err;
181
182 dn_dn2eth(mac_addr, rt->rt_local_src);
183 do {
184 seq = read_seqbegin(&neigh->ha_lock);
185 err = dev_hard_header(skb, dev, ntohs(skb->protocol),
186 neigh->ha, mac_addr, skb->len);
187 } while (read_seqretry(&neigh->ha_lock, seq));
188
189 if (err >= 0)
190 err = dev_queue_xmit(skb);
191 else {
192 kfree_skb(skb);
193 err = -EINVAL;
194 }
195 return err;
196 }
197
dn_neigh_output_packet(struct net * net,struct sock * sk,struct sk_buff * skb)198 static int dn_neigh_output_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
199 {
200 struct dst_entry *dst = skb_dst(skb);
201 struct dn_route *rt = (struct dn_route *)dst;
202 struct neighbour *neigh = rt->n;
203
204 return neigh->output(neigh, skb);
205 }
206
207 /*
208 * For talking to broadcast devices: Ethernet & PPP
209 */
dn_long_output(struct neighbour * neigh,struct sock * sk,struct sk_buff * skb)210 static int dn_long_output(struct neighbour *neigh, struct sock *sk,
211 struct sk_buff *skb)
212 {
213 struct net_device *dev = neigh->dev;
214 int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
215 unsigned char *data;
216 struct dn_long_packet *lp;
217 struct dn_skb_cb *cb = DN_SKB_CB(skb);
218
219
220 if (skb_headroom(skb) < headroom) {
221 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
222 if (skb2 == NULL) {
223 net_crit_ratelimited("dn_long_output: no memory\n");
224 kfree_skb(skb);
225 return -ENOBUFS;
226 }
227 consume_skb(skb);
228 skb = skb2;
229 net_info_ratelimited("dn_long_output: Increasing headroom\n");
230 }
231
232 data = skb_push(skb, sizeof(struct dn_long_packet) + 3);
233 lp = (struct dn_long_packet *)(data+3);
234
235 *((__le16 *)data) = cpu_to_le16(skb->len - 2);
236 *(data + 2) = 1 | DN_RT_F_PF; /* Padding */
237
238 lp->msgflg = DN_RT_PKT_LONG|(cb->rt_flags&(DN_RT_F_IE|DN_RT_F_RQR|DN_RT_F_RTS));
239 lp->d_area = lp->d_subarea = 0;
240 dn_dn2eth(lp->d_id, cb->dst);
241 lp->s_area = lp->s_subarea = 0;
242 dn_dn2eth(lp->s_id, cb->src);
243 lp->nl2 = 0;
244 lp->visit_ct = cb->hops & 0x3f;
245 lp->s_class = 0;
246 lp->pt = 0;
247
248 skb_reset_network_header(skb);
249
250 return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
251 &init_net, sk, skb, NULL, neigh->dev,
252 dn_neigh_output_packet);
253 }
254
255 /*
256 * For talking to pointopoint and multidrop devices: DDCMP and X.25
257 */
dn_short_output(struct neighbour * neigh,struct sock * sk,struct sk_buff * skb)258 static int dn_short_output(struct neighbour *neigh, struct sock *sk,
259 struct sk_buff *skb)
260 {
261 struct net_device *dev = neigh->dev;
262 int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
263 struct dn_short_packet *sp;
264 unsigned char *data;
265 struct dn_skb_cb *cb = DN_SKB_CB(skb);
266
267
268 if (skb_headroom(skb) < headroom) {
269 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
270 if (skb2 == NULL) {
271 net_crit_ratelimited("dn_short_output: no memory\n");
272 kfree_skb(skb);
273 return -ENOBUFS;
274 }
275 consume_skb(skb);
276 skb = skb2;
277 net_info_ratelimited("dn_short_output: Increasing headroom\n");
278 }
279
280 data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
281 *((__le16 *)data) = cpu_to_le16(skb->len - 2);
282 sp = (struct dn_short_packet *)(data+2);
283
284 sp->msgflg = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
285 sp->dstnode = cb->dst;
286 sp->srcnode = cb->src;
287 sp->forward = cb->hops & 0x3f;
288
289 skb_reset_network_header(skb);
290
291 return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
292 &init_net, sk, skb, NULL, neigh->dev,
293 dn_neigh_output_packet);
294 }
295
296 /*
297 * For talking to DECnet phase III nodes
298 * Phase 3 output is the same as short output, execpt that
299 * it clears the area bits before transmission.
300 */
dn_phase3_output(struct neighbour * neigh,struct sock * sk,struct sk_buff * skb)301 static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
302 struct sk_buff *skb)
303 {
304 struct net_device *dev = neigh->dev;
305 int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
306 struct dn_short_packet *sp;
307 unsigned char *data;
308 struct dn_skb_cb *cb = DN_SKB_CB(skb);
309
310 if (skb_headroom(skb) < headroom) {
311 struct sk_buff *skb2 = skb_realloc_headroom(skb, headroom);
312 if (skb2 == NULL) {
313 net_crit_ratelimited("dn_phase3_output: no memory\n");
314 kfree_skb(skb);
315 return -ENOBUFS;
316 }
317 consume_skb(skb);
318 skb = skb2;
319 net_info_ratelimited("dn_phase3_output: Increasing headroom\n");
320 }
321
322 data = skb_push(skb, sizeof(struct dn_short_packet) + 2);
323 *((__le16 *)data) = cpu_to_le16(skb->len - 2);
324 sp = (struct dn_short_packet *)(data + 2);
325
326 sp->msgflg = DN_RT_PKT_SHORT|(cb->rt_flags&(DN_RT_F_RQR|DN_RT_F_RTS));
327 sp->dstnode = cb->dst & cpu_to_le16(0x03ff);
328 sp->srcnode = cb->src & cpu_to_le16(0x03ff);
329 sp->forward = cb->hops & 0x3f;
330
331 skb_reset_network_header(skb);
332
333 return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING,
334 &init_net, sk, skb, NULL, neigh->dev,
335 dn_neigh_output_packet);
336 }
337
dn_to_neigh_output(struct net * net,struct sock * sk,struct sk_buff * skb)338 int dn_to_neigh_output(struct net *net, struct sock *sk, struct sk_buff *skb)
339 {
340 struct dst_entry *dst = skb_dst(skb);
341 struct dn_route *rt = (struct dn_route *) dst;
342 struct neighbour *neigh = rt->n;
343 struct dn_neigh *dn = container_of(neigh, struct dn_neigh, n);
344 struct dn_dev *dn_db;
345 bool use_long;
346
347 rcu_read_lock();
348 dn_db = rcu_dereference(neigh->dev->dn_ptr);
349 if (dn_db == NULL) {
350 rcu_read_unlock();
351 return -EINVAL;
352 }
353 use_long = dn_db->use_long;
354 rcu_read_unlock();
355
356 if (dn->flags & DN_NDFLAG_P3)
357 return dn_phase3_output(neigh, sk, skb);
358 if (use_long)
359 return dn_long_output(neigh, sk, skb);
360 else
361 return dn_short_output(neigh, sk, skb);
362 }
363
364 /*
365 * Unfortunately, the neighbour code uses the device in its hash
366 * function, so we don't get any advantage from it. This function
367 * basically does a neigh_lookup(), but without comparing the device
368 * field. This is required for the On-Ethernet cache
369 */
370
371 /*
372 * Pointopoint link receives a hello message
373 */
dn_neigh_pointopoint_hello(struct sk_buff * skb)374 void dn_neigh_pointopoint_hello(struct sk_buff *skb)
375 {
376 kfree_skb(skb);
377 }
378
379 /*
380 * Ethernet router hello message received
381 */
dn_neigh_router_hello(struct net * net,struct sock * sk,struct sk_buff * skb)382 int dn_neigh_router_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
383 {
384 struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
385
386 struct neighbour *neigh;
387 struct dn_neigh *dn;
388 struct dn_dev *dn_db;
389 __le16 src;
390
391 src = dn_eth2dn(msg->id);
392
393 neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
394
395 dn = container_of(neigh, struct dn_neigh, n);
396
397 if (neigh) {
398 write_lock(&neigh->lock);
399
400 neigh->used = jiffies;
401 dn_db = rcu_dereference(neigh->dev->dn_ptr);
402
403 if (!(neigh->nud_state & NUD_PERMANENT)) {
404 neigh->updated = jiffies;
405
406 if (neigh->dev->type == ARPHRD_ETHER)
407 memcpy(neigh->ha, ð_hdr(skb)->h_source, ETH_ALEN);
408
409 dn->blksize = le16_to_cpu(msg->blksize);
410 dn->priority = msg->priority;
411
412 dn->flags &= ~DN_NDFLAG_P3;
413
414 switch (msg->iinfo & DN_RT_INFO_TYPE) {
415 case DN_RT_INFO_L1RT:
416 dn->flags &=~DN_NDFLAG_R2;
417 dn->flags |= DN_NDFLAG_R1;
418 break;
419 case DN_RT_INFO_L2RT:
420 dn->flags |= DN_NDFLAG_R2;
421 }
422 }
423
424 /* Only use routers in our area */
425 if ((le16_to_cpu(src)>>10) == (le16_to_cpu((decnet_address))>>10)) {
426 if (!dn_db->router) {
427 dn_db->router = neigh_clone(neigh);
428 } else {
429 if (msg->priority > ((struct dn_neigh *)dn_db->router)->priority)
430 neigh_release(xchg(&dn_db->router, neigh_clone(neigh)));
431 }
432 }
433 write_unlock(&neigh->lock);
434 neigh_release(neigh);
435 }
436
437 kfree_skb(skb);
438 return 0;
439 }
440
441 /*
442 * Endnode hello message received
443 */
dn_neigh_endnode_hello(struct net * net,struct sock * sk,struct sk_buff * skb)444 int dn_neigh_endnode_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
445 {
446 struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
447 struct neighbour *neigh;
448 struct dn_neigh *dn;
449 __le16 src;
450
451 src = dn_eth2dn(msg->id);
452
453 neigh = __neigh_lookup(&dn_neigh_table, &src, skb->dev, 1);
454
455 dn = container_of(neigh, struct dn_neigh, n);
456
457 if (neigh) {
458 write_lock(&neigh->lock);
459
460 neigh->used = jiffies;
461
462 if (!(neigh->nud_state & NUD_PERMANENT)) {
463 neigh->updated = jiffies;
464
465 if (neigh->dev->type == ARPHRD_ETHER)
466 memcpy(neigh->ha, ð_hdr(skb)->h_source, ETH_ALEN);
467 dn->flags &= ~(DN_NDFLAG_R1 | DN_NDFLAG_R2);
468 dn->blksize = le16_to_cpu(msg->blksize);
469 dn->priority = 0;
470 }
471
472 write_unlock(&neigh->lock);
473 neigh_release(neigh);
474 }
475
476 kfree_skb(skb);
477 return 0;
478 }
479
dn_find_slot(char * base,int max,int priority)480 static char *dn_find_slot(char *base, int max, int priority)
481 {
482 int i;
483 unsigned char *min = NULL;
484
485 base += 6; /* skip first id */
486
487 for(i = 0; i < max; i++) {
488 if (!min || (*base < *min))
489 min = base;
490 base += 7; /* find next priority */
491 }
492
493 if (!min)
494 return NULL;
495
496 return (*min < priority) ? (min - 6) : NULL;
497 }
498
499 struct elist_cb_state {
500 struct net_device *dev;
501 unsigned char *ptr;
502 unsigned char *rs;
503 int t, n;
504 };
505
neigh_elist_cb(struct neighbour * neigh,void * _info)506 static void neigh_elist_cb(struct neighbour *neigh, void *_info)
507 {
508 struct elist_cb_state *s = _info;
509 struct dn_neigh *dn;
510
511 if (neigh->dev != s->dev)
512 return;
513
514 dn = container_of(neigh, struct dn_neigh, n);
515 if (!(dn->flags & (DN_NDFLAG_R1|DN_NDFLAG_R2)))
516 return;
517
518 if (s->t == s->n)
519 s->rs = dn_find_slot(s->ptr, s->n, dn->priority);
520 else
521 s->t++;
522 if (s->rs == NULL)
523 return;
524
525 dn_dn2eth(s->rs, dn->addr);
526 s->rs += 6;
527 *(s->rs) = neigh->nud_state & NUD_CONNECTED ? 0x80 : 0x0;
528 *(s->rs) |= dn->priority;
529 s->rs++;
530 }
531
dn_neigh_elist(struct net_device * dev,unsigned char * ptr,int n)532 int dn_neigh_elist(struct net_device *dev, unsigned char *ptr, int n)
533 {
534 struct elist_cb_state state;
535
536 state.dev = dev;
537 state.t = 0;
538 state.n = n;
539 state.ptr = ptr;
540 state.rs = ptr;
541
542 neigh_for_each(&dn_neigh_table, neigh_elist_cb, &state);
543
544 return state.t;
545 }
546
547
548 #ifdef CONFIG_PROC_FS
549
dn_neigh_format_entry(struct seq_file * seq,struct neighbour * n)550 static inline void dn_neigh_format_entry(struct seq_file *seq,
551 struct neighbour *n)
552 {
553 struct dn_neigh *dn = container_of(n, struct dn_neigh, n);
554 char buf[DN_ASCBUF_LEN];
555
556 read_lock(&n->lock);
557 seq_printf(seq, "%-7s %s%s%s %02x %02d %07ld %-8s\n",
558 dn_addr2asc(le16_to_cpu(dn->addr), buf),
559 (dn->flags&DN_NDFLAG_R1) ? "1" : "-",
560 (dn->flags&DN_NDFLAG_R2) ? "2" : "-",
561 (dn->flags&DN_NDFLAG_P3) ? "3" : "-",
562 dn->n.nud_state,
563 refcount_read(&dn->n.refcnt),
564 dn->blksize,
565 (dn->n.dev) ? dn->n.dev->name : "?");
566 read_unlock(&n->lock);
567 }
568
dn_neigh_seq_show(struct seq_file * seq,void * v)569 static int dn_neigh_seq_show(struct seq_file *seq, void *v)
570 {
571 if (v == SEQ_START_TOKEN) {
572 seq_puts(seq, "Addr Flags State Use Blksize Dev\n");
573 } else {
574 dn_neigh_format_entry(seq, v);
575 }
576
577 return 0;
578 }
579
dn_neigh_seq_start(struct seq_file * seq,loff_t * pos)580 static void *dn_neigh_seq_start(struct seq_file *seq, loff_t *pos)
581 {
582 return neigh_seq_start(seq, pos, &dn_neigh_table,
583 NEIGH_SEQ_NEIGH_ONLY);
584 }
585
586 static const struct seq_operations dn_neigh_seq_ops = {
587 .start = dn_neigh_seq_start,
588 .next = neigh_seq_next,
589 .stop = neigh_seq_stop,
590 .show = dn_neigh_seq_show,
591 };
592 #endif
593
dn_neigh_init(void)594 void __init dn_neigh_init(void)
595 {
596 neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
597 proc_create_net("decnet_neigh", 0444, init_net.proc_net,
598 &dn_neigh_seq_ops, sizeof(struct neigh_seq_state));
599 }
600
dn_neigh_cleanup(void)601 void __exit dn_neigh_cleanup(void)
602 {
603 remove_proc_entry("decnet_neigh", init_net.proc_net);
604 neigh_table_clear(NEIGH_DN_TABLE, &dn_neigh_table);
605 }
606