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