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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 Routing Functions (Endnode and Router)
7  *
8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
10  *
11  * Changes:
12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
13  *                                 "return-to-sender" bits on outgoing
14  *                                 packets.
15  *              Steve Whitehouse : Timeouts for cached routes.
16  *              Steve Whitehouse : Use dst cache for input routes too.
17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
18  *              Steve Whitehouse : Rework routing functions to better fit
19  *                                 DECnet routing design
20  *              Alexey Kuznetsov : New SMP locking
21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
23  *                                 Fixed possible skb leak in rtnetlink funcs.
24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
25  *                                 Alexey Kuznetsov's finer grained locking
26  *                                 from ipv4/route.c.
27  *              Steve Whitehouse : Routing is now starting to look like a
28  *                                 sensible set of code now, mainly due to
29  *                                 my copying the IPv4 routing code. The
30  *                                 hooks here are modified and will continue
31  *                                 to evolve for a while.
32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
33  *                                 stuff. Look out raw sockets your days
34  *                                 are numbered!
35  *              Steve Whitehouse : Added return-to-sender functions. Added
36  *                                 backlog congestion level return codes.
37  *              Steve Whitehouse : Fixed bug where routes were set up with
38  *                                 no ref count on net devices.
39  *              Steve Whitehouse : RCU for the route cache
40  *              Steve Whitehouse : Preparations for the flow cache
41  *              Steve Whitehouse : Prepare for nonlinear skbs
42  */
43
44 /******************************************************************************
45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
46     
47     This program is free software; you can redistribute it and/or modify
48     it under the terms of the GNU General Public License as published by
49     the Free Software Foundation; either version 2 of the License, or
50     any later version.
51
52     This program is distributed in the hope that it will be useful,
53     but WITHOUT ANY WARRANTY; without even the implied warranty of
54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
55     GNU General Public License for more details.
56 *******************************************************************************/
57
58 #include <linux/errno.h>
59 #include <linux/types.h>
60 #include <linux/socket.h>
61 #include <linux/in.h>
62 #include <linux/kernel.h>
63 #include <linux/sockios.h>
64 #include <linux/net.h>
65 #include <linux/netdevice.h>
66 #include <linux/inet.h>
67 #include <linux/route.h>
68 #include <linux/in_route.h>
69 #include <net/sock.h>
70 #include <linux/mm.h>
71 #include <linux/proc_fs.h>
72 #include <linux/seq_file.h>
73 #include <linux/init.h>
74 #include <linux/rtnetlink.h>
75 #include <linux/string.h>
76 #include <linux/netfilter_decnet.h>
77 #include <linux/rcupdate.h>
78 #include <linux/times.h>
79 #include <asm/errno.h>
80 #include <net/neighbour.h>
81 #include <net/dst.h>
82 #include <net/flow.h>
83 #include <net/dn.h>
84 #include <net/dn_dev.h>
85 #include <net/dn_nsp.h>
86 #include <net/dn_route.h>
87 #include <net/dn_neigh.h>
88 #include <net/dn_fib.h>
89
90 struct dn_rt_hash_bucket
91 {
92         struct dn_route *chain;
93         spinlock_t lock;
94 } __attribute__((__aligned__(8)));
95
96 extern struct neigh_table dn_neigh_table;
97
98
99 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
100
101 static const int dn_rt_min_delay = 2 * HZ;
102 static const int dn_rt_max_delay = 10 * HZ;
103 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
104
105 static unsigned long dn_rt_deadline;
106
107 static int dn_dst_gc(void);
108 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
109 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
110 static void dn_dst_link_failure(struct sk_buff *);
111 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
112 static int dn_route_input(struct sk_buff *);
113 static void dn_run_flush(unsigned long dummy);
114
115 static struct dn_rt_hash_bucket *dn_rt_hash_table;
116 static unsigned dn_rt_hash_mask;
117
118 static struct timer_list dn_route_timer;
119 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
120 int decnet_dst_gc_interval = 2;
121
122 static struct dst_ops dn_dst_ops = {
123         .family =               PF_DECnet,
124         .protocol =             __constant_htons(ETH_P_DNA_RT),
125         .gc_thresh =            128,
126         .gc =                   dn_dst_gc,
127         .check =                dn_dst_check,
128         .negative_advice =      dn_dst_negative_advice,
129         .link_failure =         dn_dst_link_failure,
130         .update_pmtu =          dn_dst_update_pmtu,
131         .entry_size =           sizeof(struct dn_route),
132         .entries =              ATOMIC_INIT(0),
133 };
134
135 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
136 {
137         __u16 tmp = (__u16 __force)(src ^ dst);
138         tmp ^= (tmp >> 3);
139         tmp ^= (tmp >> 5);
140         tmp ^= (tmp >> 10);
141         return dn_rt_hash_mask & (unsigned)tmp;
142 }
143
144 static inline void dnrt_free(struct dn_route *rt)
145 {
146         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
147 }
148
149 static inline void dnrt_drop(struct dn_route *rt)
150 {
151         dst_release(&rt->u.dst);
152         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
153 }
154
155 static void dn_dst_check_expire(unsigned long dummy)
156 {
157         int i;
158         struct dn_route *rt, **rtp;
159         unsigned long now = jiffies;
160         unsigned long expire = 120 * HZ;
161
162         for(i = 0; i <= dn_rt_hash_mask; i++) {
163                 rtp = &dn_rt_hash_table[i].chain;
164
165                 spin_lock(&dn_rt_hash_table[i].lock);
166                 while((rt=*rtp) != NULL) {
167                         if (atomic_read(&rt->u.dst.__refcnt) ||
168                                         (now - rt->u.dst.lastuse) < expire) {
169                                 rtp = &rt->u.rt_next;
170                                 continue;
171                         }
172                         *rtp = rt->u.rt_next;
173                         rt->u.rt_next = NULL;
174                         dnrt_free(rt);
175                 }
176                 spin_unlock(&dn_rt_hash_table[i].lock);
177
178                 if ((jiffies - now) > 0)
179                         break;
180         }
181
182         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
183 }
184
185 static int dn_dst_gc(void)
186 {
187         struct dn_route *rt, **rtp;
188         int i;
189         unsigned long now = jiffies;
190         unsigned long expire = 10 * HZ;
191
192         for(i = 0; i <= dn_rt_hash_mask; i++) {
193
194                 spin_lock_bh(&dn_rt_hash_table[i].lock);
195                 rtp = &dn_rt_hash_table[i].chain;
196
197                 while((rt=*rtp) != NULL) {
198                         if (atomic_read(&rt->u.dst.__refcnt) ||
199                                         (now - rt->u.dst.lastuse) < expire) {
200                                 rtp = &rt->u.rt_next;
201                                 continue;
202                         }
203                         *rtp = rt->u.rt_next;
204                         rt->u.rt_next = NULL;
205                         dnrt_drop(rt);
206                         break;
207                 }
208                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
209         }
210
211         return 0;
212 }
213
214 /*
215  * The decnet standards don't impose a particular minimum mtu, what they
216  * do insist on is that the routing layer accepts a datagram of at least
217  * 230 bytes long. Here we have to subtract the routing header length from
218  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
219  * assume the worst and use a long header size.
220  *
221  * We update both the mtu and the advertised mss (i.e. the segment size we
222  * advertise to the other end).
223  */
224 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
225 {
226         u32 min_mtu = 230;
227         struct dn_dev *dn = dst->neighbour ?
228                             (struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
229
230         if (dn && dn->use_long == 0)
231                 min_mtu -= 6;
232         else
233                 min_mtu -= 21;
234
235         if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= min_mtu) {
236                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
237                         dst->metrics[RTAX_MTU-1] = mtu;
238                         dst_set_expires(dst, dn_rt_mtu_expires);
239                 }
240                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
241                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
242                         if (dst->metrics[RTAX_ADVMSS-1] > mss)
243                                 dst->metrics[RTAX_ADVMSS-1] = mss;
244                 }
245         }
246 }
247
248 /* 
249  * When a route has been marked obsolete. (e.g. routing cache flush)
250  */
251 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
252 {
253         return NULL;
254 }
255
256 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
257 {
258         dst_release(dst);
259         return NULL;
260 }
261
262 static void dn_dst_link_failure(struct sk_buff *skb)
263 {
264         return;
265 }
266
267 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
268 {
269         return memcmp(&fl1->nl_u.dn_u, &fl2->nl_u.dn_u, sizeof(fl1->nl_u.dn_u)) == 0 &&
270                 fl1->oif == fl2->oif &&
271                 fl1->iif == fl2->iif;
272 }
273
274 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
275 {
276         struct dn_route *rth, **rthp;
277         unsigned long now = jiffies;
278
279         rthp = &dn_rt_hash_table[hash].chain;
280
281         spin_lock_bh(&dn_rt_hash_table[hash].lock);
282         while((rth = *rthp) != NULL) {
283                 if (compare_keys(&rth->fl, &rt->fl)) {
284                         /* Put it first */
285                         *rthp = rth->u.rt_next;
286                         rcu_assign_pointer(rth->u.rt_next,
287                                            dn_rt_hash_table[hash].chain);
288                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
289
290                         rth->u.dst.__use++;
291                         dst_hold(&rth->u.dst);
292                         rth->u.dst.lastuse = now;
293                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
294
295                         dnrt_drop(rt);
296                         *rp = rth;
297                         return 0;
298                 }
299                 rthp = &rth->u.rt_next;
300         }
301
302         rcu_assign_pointer(rt->u.rt_next, dn_rt_hash_table[hash].chain);
303         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
304         
305         dst_hold(&rt->u.dst);
306         rt->u.dst.__use++;
307         rt->u.dst.lastuse = now;
308         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
309         *rp = rt;
310         return 0;
311 }
312
313 void dn_run_flush(unsigned long dummy)
314 {
315         int i;
316         struct dn_route *rt, *next;
317
318         for(i = 0; i < dn_rt_hash_mask; i++) {
319                 spin_lock_bh(&dn_rt_hash_table[i].lock);
320
321                 if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
322                         goto nothing_to_declare;
323
324                 for(; rt; rt=next) {
325                         next = rt->u.rt_next;
326                         rt->u.rt_next = NULL;
327                         dst_free((struct dst_entry *)rt);
328                 }
329
330 nothing_to_declare:
331                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
332         }
333 }
334
335 static DEFINE_SPINLOCK(dn_rt_flush_lock);
336
337 void dn_rt_cache_flush(int delay)
338 {
339         unsigned long now = jiffies;
340         int user_mode = !in_interrupt();
341
342         if (delay < 0)
343                 delay = dn_rt_min_delay;
344
345         spin_lock_bh(&dn_rt_flush_lock);
346
347         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
348                 long tmo = (long)(dn_rt_deadline - now);
349
350                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
351                         tmo = 0;
352
353                 if (delay > tmo)
354                         delay = tmo;
355         }
356
357         if (delay <= 0) {
358                 spin_unlock_bh(&dn_rt_flush_lock);
359                 dn_run_flush(0);
360                 return;
361         }
362
363         if (dn_rt_deadline == 0)
364                 dn_rt_deadline = now + dn_rt_max_delay;
365
366         dn_rt_flush_timer.expires = now + delay;
367         add_timer(&dn_rt_flush_timer);
368         spin_unlock_bh(&dn_rt_flush_lock);
369 }
370
371 /**
372  * dn_return_short - Return a short packet to its sender
373  * @skb: The packet to return
374  *
375  */
376 static int dn_return_short(struct sk_buff *skb)
377 {
378         struct dn_skb_cb *cb;
379         unsigned char *ptr;
380         __le16 *src;
381         __le16 *dst;
382         __le16 tmp;
383
384         /* Add back headers */
385         skb_push(skb, skb->data - skb->nh.raw);
386
387         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
388                 return NET_RX_DROP;
389
390         cb = DN_SKB_CB(skb);
391         /* Skip packet length and point to flags */
392         ptr = skb->data + 2;
393         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
394
395         dst = (__le16 *)ptr;
396         ptr += 2;
397         src = (__le16 *)ptr;
398         ptr += 2;
399         *ptr = 0; /* Zero hop count */
400
401         /* Swap source and destination */
402         tmp  = *src;
403         *src = *dst;
404         *dst = tmp;
405
406         skb->pkt_type = PACKET_OUTGOING;
407         dn_rt_finish_output(skb, NULL, NULL);
408         return NET_RX_SUCCESS;
409 }
410
411 /**
412  * dn_return_long - Return a long packet to its sender
413  * @skb: The long format packet to return
414  *
415  */
416 static int dn_return_long(struct sk_buff *skb)
417 {
418         struct dn_skb_cb *cb;
419         unsigned char *ptr;
420         unsigned char *src_addr, *dst_addr;
421         unsigned char tmp[ETH_ALEN];
422
423         /* Add back all headers */
424         skb_push(skb, skb->data - skb->nh.raw);
425
426         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
427                 return NET_RX_DROP;
428
429         cb = DN_SKB_CB(skb);
430         /* Ignore packet length and point to flags */
431         ptr = skb->data + 2;
432
433         /* Skip padding */
434         if (*ptr & DN_RT_F_PF) {
435                 char padlen = (*ptr & ~DN_RT_F_PF);
436                 ptr += padlen;
437         }
438
439         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
440         ptr += 2;
441         dst_addr = ptr;
442         ptr += 8;
443         src_addr = ptr;
444         ptr += 6;
445         *ptr = 0; /* Zero hop count */
446
447         /* Swap source and destination */
448         memcpy(tmp, src_addr, ETH_ALEN);
449         memcpy(src_addr, dst_addr, ETH_ALEN);
450         memcpy(dst_addr, tmp, ETH_ALEN);
451
452         skb->pkt_type = PACKET_OUTGOING;
453         dn_rt_finish_output(skb, dst_addr, src_addr);
454         return NET_RX_SUCCESS;
455 }
456
457 /**
458  * dn_route_rx_packet - Try and find a route for an incoming packet
459  * @skb: The packet to find a route for
460  *
461  * Returns: result of input function if route is found, error code otherwise
462  */
463 static int dn_route_rx_packet(struct sk_buff *skb)
464 {
465         struct dn_skb_cb *cb = DN_SKB_CB(skb);
466         int err;
467
468         if ((err = dn_route_input(skb)) == 0)
469                 return dst_input(skb);
470
471         if (decnet_debug_level & 4) {
472                 char *devname = skb->dev ? skb->dev->name : "???";
473                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
474                 printk(KERN_DEBUG
475                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
476                         (int)cb->rt_flags, devname, skb->len,
477                         dn_ntohs(cb->src), dn_ntohs(cb->dst),
478                         err, skb->pkt_type);
479         }
480
481         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
482                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
483                         case DN_RT_PKT_SHORT:
484                                 return dn_return_short(skb);
485                         case DN_RT_PKT_LONG:
486                                 return dn_return_long(skb);
487                 }
488         }
489
490         kfree_skb(skb);
491         return NET_RX_DROP;
492 }
493
494 static int dn_route_rx_long(struct sk_buff *skb)
495 {
496         struct dn_skb_cb *cb = DN_SKB_CB(skb);
497         unsigned char *ptr = skb->data;
498
499         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
500                 goto drop_it;
501
502         skb_pull(skb, 20);
503         skb->h.raw = skb->data;
504
505         /* Destination info */
506         ptr += 2;
507         cb->dst = dn_eth2dn(ptr);
508         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
509                 goto drop_it;
510         ptr += 6;
511
512
513         /* Source info */
514         ptr += 2;
515         cb->src = dn_eth2dn(ptr);
516         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
517                 goto drop_it;
518         ptr += 6;
519         /* Other junk */
520         ptr++;
521         cb->hops = *ptr++; /* Visit Count */
522
523         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
524
525 drop_it:
526         kfree_skb(skb);
527         return NET_RX_DROP;
528 }
529
530
531
532 static int dn_route_rx_short(struct sk_buff *skb)
533 {
534         struct dn_skb_cb *cb = DN_SKB_CB(skb);
535         unsigned char *ptr = skb->data;
536
537         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
538                 goto drop_it;
539
540         skb_pull(skb, 5);
541         skb->h.raw = skb->data;
542
543         cb->dst = *(__le16 *)ptr;
544         ptr += 2;
545         cb->src = *(__le16 *)ptr;
546         ptr += 2;
547         cb->hops = *ptr & 0x3f;
548
549         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
550
551 drop_it:
552         kfree_skb(skb);
553         return NET_RX_DROP;
554 }
555
556 static int dn_route_discard(struct sk_buff *skb)
557 {
558         /*
559          * I know we drop the packet here, but thats considered success in
560          * this case
561          */
562         kfree_skb(skb);
563         return NET_RX_SUCCESS;
564 }
565
566 static int dn_route_ptp_hello(struct sk_buff *skb)
567 {
568         dn_dev_hello(skb);
569         dn_neigh_pointopoint_hello(skb);
570         return NET_RX_SUCCESS;
571 }
572
573 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
574 {
575         struct dn_skb_cb *cb;
576         unsigned char flags = 0;
577         __u16 len = dn_ntohs(*(__le16 *)skb->data);
578         struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
579         unsigned char padlen = 0;
580
581         if (dn == NULL)
582                 goto dump_it;
583
584         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
585                 goto out;
586
587         if (!pskb_may_pull(skb, 3))
588                 goto dump_it;
589
590         skb_pull(skb, 2);
591
592         if (len > skb->len)
593                 goto dump_it;
594
595         skb_trim(skb, len);
596
597         flags = *skb->data;
598
599         cb = DN_SKB_CB(skb);
600         cb->stamp = jiffies;
601         cb->iif = dev->ifindex;
602
603         /*
604          * If we have padding, remove it.
605          */
606         if (flags & DN_RT_F_PF) {
607                 padlen = flags & ~DN_RT_F_PF;
608                 if (!pskb_may_pull(skb, padlen + 1))
609                         goto dump_it;
610                 skb_pull(skb, padlen);
611                 flags = *skb->data;
612         }
613
614         skb->nh.raw = skb->data;
615
616         /*
617          * Weed out future version DECnet
618          */
619         if (flags & DN_RT_F_VER)
620                 goto dump_it;
621
622         cb->rt_flags = flags;
623
624         if (decnet_debug_level & 1)
625                 printk(KERN_DEBUG 
626                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
627                         (int)flags, (dev) ? dev->name : "???", len, skb->len, 
628                         padlen);
629
630         if (flags & DN_RT_PKT_CNTL) {
631                 if (unlikely(skb_linearize(skb)))
632                         goto dump_it;
633
634                 switch(flags & DN_RT_CNTL_MSK) {
635                         case DN_RT_PKT_INIT:
636                                 dn_dev_init_pkt(skb);
637                                 break;
638                         case DN_RT_PKT_VERI:
639                                 dn_dev_veri_pkt(skb);
640                                 break;
641                 }
642
643                 if (dn->parms.state != DN_DEV_S_RU)
644                         goto dump_it;
645
646                 switch(flags & DN_RT_CNTL_MSK) {
647                         case DN_RT_PKT_HELO:
648                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);
649
650                         case DN_RT_PKT_L1RT:
651                         case DN_RT_PKT_L2RT:
652                                 return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
653                         case DN_RT_PKT_ERTH:
654                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);
655
656                         case DN_RT_PKT_EEDH:
657                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
658                 }
659         } else {
660                 if (dn->parms.state != DN_DEV_S_RU)
661                         goto dump_it;
662
663                 skb_pull(skb, 1); /* Pull flags */
664
665                 switch(flags & DN_RT_PKT_MSK) {
666                         case DN_RT_PKT_LONG:
667                                 return dn_route_rx_long(skb);
668                         case DN_RT_PKT_SHORT:
669                                 return dn_route_rx_short(skb);
670                 }
671         }
672
673 dump_it:
674         kfree_skb(skb);
675 out:
676         return NET_RX_DROP;
677 }
678
679 static int dn_output(struct sk_buff *skb)
680 {
681         struct dst_entry *dst = skb->dst;
682         struct dn_route *rt = (struct dn_route *)dst;
683         struct net_device *dev = dst->dev;
684         struct dn_skb_cb *cb = DN_SKB_CB(skb);
685         struct neighbour *neigh;
686
687         int err = -EINVAL;
688
689         if ((neigh = dst->neighbour) == NULL)
690                 goto error;
691
692         skb->dev = dev;
693
694         cb->src = rt->rt_saddr;
695         cb->dst = rt->rt_daddr;
696
697         /*
698          * Always set the Intra-Ethernet bit on all outgoing packets
699          * originated on this node. Only valid flag from upper layers
700          * is return-to-sender-requested. Set hop count to 0 too.
701          */
702         cb->rt_flags &= ~DN_RT_F_RQR;
703         cb->rt_flags |= DN_RT_F_IE;
704         cb->hops = 0;
705
706         return NF_HOOK(PF_DECnet, NF_DN_LOCAL_OUT, skb, NULL, dev, neigh->output);
707
708 error:
709         if (net_ratelimit())
710                 printk(KERN_DEBUG "dn_output: This should not happen\n");
711
712         kfree_skb(skb);
713
714         return err;
715 }
716
717 static int dn_forward(struct sk_buff *skb)
718 {
719         struct dn_skb_cb *cb = DN_SKB_CB(skb);
720         struct dst_entry *dst = skb->dst;
721         struct dn_dev *dn_db = dst->dev->dn_ptr;
722         struct dn_route *rt;
723         struct neighbour *neigh = dst->neighbour;
724         int header_len;
725 #ifdef CONFIG_NETFILTER
726         struct net_device *dev = skb->dev;
727 #endif
728
729         if (skb->pkt_type != PACKET_HOST)
730                 goto drop;
731
732         /* Ensure that we have enough space for headers */
733         rt = (struct dn_route *)skb->dst;
734         header_len = dn_db->use_long ? 21 : 6;
735         if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
736                 goto drop;
737
738         /*
739          * Hop count exceeded.
740          */
741         if (++cb->hops > 30)
742                 goto drop;
743
744         skb->dev = rt->u.dst.dev;
745
746         /*
747          * If packet goes out same interface it came in on, then set
748          * the Intra-Ethernet bit. This has no effect for short
749          * packets, so we don't need to test for them here.
750          */
751         cb->rt_flags &= ~DN_RT_F_IE;
752         if (rt->rt_flags & RTCF_DOREDIRECT)
753                 cb->rt_flags |= DN_RT_F_IE;
754
755         return NF_HOOK(PF_DECnet, NF_DN_FORWARD, skb, dev, skb->dev, neigh->output);
756
757 drop:
758         kfree_skb(skb);
759         return NET_RX_DROP;
760 }
761
762 /*
763  * Drop packet. This is used for endnodes and for
764  * when we should not be forwarding packets from
765  * this dest.
766  */
767 static int dn_blackhole(struct sk_buff *skb)
768 {
769         kfree_skb(skb);
770         return NET_RX_DROP;
771 }
772
773 /*
774  * Used to catch bugs. This should never normally get
775  * called.
776  */
777 static int dn_rt_bug(struct sk_buff *skb)
778 {
779         if (net_ratelimit()) {
780                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
781
782                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
783                                 dn_ntohs(cb->src), dn_ntohs(cb->dst));
784         }
785
786         kfree_skb(skb);
787
788         return NET_RX_BAD;
789 }
790
791 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
792 {
793         struct dn_fib_info *fi = res->fi;
794         struct net_device *dev = rt->u.dst.dev;
795         struct neighbour *n;
796         unsigned mss;
797
798         if (fi) {
799                 if (DN_FIB_RES_GW(*res) &&
800                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
801                         rt->rt_gateway = DN_FIB_RES_GW(*res);
802                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
803                        sizeof(rt->u.dst.metrics));
804         }
805         rt->rt_type = res->type;
806
807         if (dev != NULL && rt->u.dst.neighbour == NULL) {
808                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
809                 if (IS_ERR(n))
810                         return PTR_ERR(n);
811                 rt->u.dst.neighbour = n;
812         }
813
814         if (rt->u.dst.metrics[RTAX_MTU-1] == 0 || 
815             rt->u.dst.metrics[RTAX_MTU-1] > rt->u.dst.dev->mtu)
816                 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
817         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
818         if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0 ||
819             rt->u.dst.metrics[RTAX_ADVMSS-1] > mss)
820                 rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
821         return 0;
822 }
823
824 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
825 {
826         __u16 tmp = dn_ntohs(addr1) ^ dn_ntohs(addr2);
827         int match = 16;
828         while(tmp) {
829                 tmp >>= 1;
830                 match--;
831         }
832         return match;
833 }
834
835 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
836 {
837         __le16 saddr = 0;
838         struct dn_dev *dn_db = dev->dn_ptr;
839         struct dn_ifaddr *ifa;
840         int best_match = 0;
841         int ret;
842
843         read_lock(&dev_base_lock);
844         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
845                 if (ifa->ifa_scope > scope)
846                         continue;
847                 if (!daddr) {
848                         saddr = ifa->ifa_local;
849                         break;
850                 }
851                 ret = dn_match_addr(daddr, ifa->ifa_local);
852                 if (ret > best_match)
853                         saddr = ifa->ifa_local;
854                 if (best_match == 0)
855                         saddr = ifa->ifa_local;
856         }
857         read_unlock(&dev_base_lock);
858
859         return saddr;
860 }
861
862 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
863 {
864         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
865 }
866
867 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
868 {
869         __le16 mask = dnet_make_mask(res->prefixlen);
870         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
871 }
872
873 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
874 {
875         struct flowi fl = { .nl_u = { .dn_u = 
876                                       { .daddr = oldflp->fld_dst,
877                                         .saddr = oldflp->fld_src,
878                                         .scope = RT_SCOPE_UNIVERSE,
879 #ifdef CONFIG_DECNET_ROUTE_FWMARK
880                                         .fwmark = oldflp->fld_fwmark
881 #endif
882                                      } },
883                             .iif = loopback_dev.ifindex,
884                             .oif = oldflp->oif };
885         struct dn_route *rt = NULL;
886         struct net_device *dev_out = NULL;
887         struct neighbour *neigh = NULL;
888         unsigned hash;
889         unsigned flags = 0;
890         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
891         int err;
892         int free_res = 0;
893         __le16 gateway = 0;
894
895         if (decnet_debug_level & 16)
896                 printk(KERN_DEBUG
897                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
898                        " iif=%d oif=%d\n", dn_ntohs(oldflp->fld_dst),
899                        dn_ntohs(oldflp->fld_src),
900                        oldflp->fld_fwmark, loopback_dev.ifindex, oldflp->oif);
901
902         /* If we have an output interface, verify its a DECnet device */
903         if (oldflp->oif) {
904                 dev_out = dev_get_by_index(oldflp->oif);
905                 err = -ENODEV;
906                 if (dev_out && dev_out->dn_ptr == NULL) {
907                         dev_put(dev_out);
908                         dev_out = NULL;
909                 }
910                 if (dev_out == NULL)
911                         goto out;
912         }
913
914         /* If we have a source address, verify that its a local address */
915         if (oldflp->fld_src) {
916                 err = -EADDRNOTAVAIL;
917
918                 if (dev_out) {
919                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
920                                 goto source_ok;
921                         dev_put(dev_out);
922                         goto out;
923                 }
924                 read_lock(&dev_base_lock);
925                 for(dev_out = dev_base; dev_out; dev_out = dev_out->next) {
926                         if (!dev_out->dn_ptr)
927                                 continue;
928                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
929                                 break;
930                 }
931                 read_unlock(&dev_base_lock);
932                 if (dev_out == NULL)
933                         goto out;
934                 dev_hold(dev_out);
935 source_ok:
936                 ;
937         }
938
939         /* No destination? Assume its local */
940         if (!fl.fld_dst) {
941                 fl.fld_dst = fl.fld_src;
942
943                 err = -EADDRNOTAVAIL;
944                 if (dev_out)
945                         dev_put(dev_out);
946                 dev_out = &loopback_dev;
947                 dev_hold(dev_out);
948                 if (!fl.fld_dst) {
949                         fl.fld_dst =
950                         fl.fld_src = dnet_select_source(dev_out, 0,
951                                                        RT_SCOPE_HOST);
952                         if (!fl.fld_dst)
953                                 goto out;
954                 }
955                 fl.oif = loopback_dev.ifindex;
956                 res.type = RTN_LOCAL;
957                 goto make_route;
958         }
959
960         if (decnet_debug_level & 16)
961                 printk(KERN_DEBUG
962                        "dn_route_output_slow: initial checks complete."
963                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
964                        dn_ntohs(fl.fld_dst), dn_ntohs(fl.fld_src),
965                        fl.oif, try_hard);
966
967         /*
968          * N.B. If the kernel is compiled without router support then
969          * dn_fib_lookup() will evaluate to non-zero so this if () block
970          * will always be executed.
971          */
972         err = -ESRCH;
973         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
974                 struct dn_dev *dn_db;
975                 if (err != -ESRCH)
976                         goto out;
977                 /*
978                  * Here the fallback is basically the standard algorithm for 
979                  * routing in endnodes which is described in the DECnet routing
980                  * docs
981                  *
982                  * If we are not trying hard, look in neighbour cache.
983                  * The result is tested to ensure that if a specific output
984                  * device/source address was requested, then we honour that 
985                  * here
986                  */
987                 if (!try_hard) {
988                         neigh = neigh_lookup_nodev(&dn_neigh_table, &fl.fld_dst);
989                         if (neigh) {
990                                 if ((oldflp->oif && 
991                                     (neigh->dev->ifindex != oldflp->oif)) ||
992                                     (oldflp->fld_src &&
993                                     (!dn_dev_islocal(neigh->dev,
994                                                       oldflp->fld_src)))) {
995                                         neigh_release(neigh);
996                                         neigh = NULL;
997                                 } else {
998                                         if (dev_out)
999                                                 dev_put(dev_out);
1000                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1001                                                 dev_out = &loopback_dev;
1002                                                 res.type = RTN_LOCAL;
1003                                         } else {
1004                                                 dev_out = neigh->dev;
1005                                         }
1006                                         dev_hold(dev_out);
1007                                         goto select_source;
1008                                 }
1009                         }
1010                 }
1011
1012                 /* Not there? Perhaps its a local address */
1013                 if (dev_out == NULL)
1014                         dev_out = dn_dev_get_default();
1015                 err = -ENODEV;
1016                 if (dev_out == NULL)
1017                         goto out;
1018                 dn_db = dev_out->dn_ptr;
1019                 /* Possible improvement - check all devices for local addr */
1020                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1021                         dev_put(dev_out);
1022                         dev_out = &loopback_dev;
1023                         dev_hold(dev_out);
1024                         res.type = RTN_LOCAL;
1025                         goto select_source;
1026                 }
1027                 /* Not local either.... try sending it to the default router */
1028                 neigh = neigh_clone(dn_db->router);
1029                 BUG_ON(neigh && neigh->dev != dev_out);
1030
1031                 /* Ok then, we assume its directly connected and move on */
1032 select_source:
1033                 if (neigh)
1034                         gateway = ((struct dn_neigh *)neigh)->addr;
1035                 if (gateway == 0)
1036                         gateway = fl.fld_dst;
1037                 if (fl.fld_src == 0) {
1038                         fl.fld_src = dnet_select_source(dev_out, gateway,
1039                                                          res.type == RTN_LOCAL ?
1040                                                          RT_SCOPE_HOST : 
1041                                                          RT_SCOPE_LINK);
1042                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1043                                 goto e_addr;
1044                 }
1045                 fl.oif = dev_out->ifindex;
1046                 goto make_route;
1047         }
1048         free_res = 1;
1049
1050         if (res.type == RTN_NAT)
1051                 goto e_inval;
1052
1053         if (res.type == RTN_LOCAL) {
1054                 if (!fl.fld_src)
1055                         fl.fld_src = fl.fld_dst;
1056                 if (dev_out)
1057                         dev_put(dev_out);
1058                 dev_out = &loopback_dev;
1059                 dev_hold(dev_out);
1060                 fl.oif = dev_out->ifindex;
1061                 if (res.fi)
1062                         dn_fib_info_put(res.fi);
1063                 res.fi = NULL;
1064                 goto make_route;
1065         }
1066
1067         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1068                 dn_fib_select_multipath(&fl, &res);
1069
1070         /* 
1071          * We could add some logic to deal with default routes here and
1072          * get rid of some of the special casing above.
1073          */
1074
1075         if (!fl.fld_src)
1076                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1077         
1078         if (dev_out)
1079                 dev_put(dev_out);
1080         dev_out = DN_FIB_RES_DEV(res);
1081         dev_hold(dev_out);
1082         fl.oif = dev_out->ifindex;
1083         gateway = DN_FIB_RES_GW(res);
1084
1085 make_route:
1086         if (dev_out->flags & IFF_LOOPBACK)
1087                 flags |= RTCF_LOCAL;
1088
1089         rt = dst_alloc(&dn_dst_ops);
1090         if (rt == NULL)
1091                 goto e_nobufs;
1092
1093         atomic_set(&rt->u.dst.__refcnt, 1);
1094         rt->u.dst.flags   = DST_HOST;
1095
1096         rt->fl.fld_src    = oldflp->fld_src;
1097         rt->fl.fld_dst    = oldflp->fld_dst;
1098         rt->fl.oif        = oldflp->oif;
1099         rt->fl.iif        = 0;
1100 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1101         rt->fl.fld_fwmark = oldflp->fld_fwmark;
1102 #endif
1103
1104         rt->rt_saddr      = fl.fld_src;
1105         rt->rt_daddr      = fl.fld_dst;
1106         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1107         rt->rt_local_src  = fl.fld_src;
1108
1109         rt->rt_dst_map    = fl.fld_dst;
1110         rt->rt_src_map    = fl.fld_src;
1111
1112         rt->u.dst.dev = dev_out;
1113         dev_hold(dev_out);
1114         rt->u.dst.neighbour = neigh;
1115         neigh = NULL;
1116
1117         rt->u.dst.lastuse = jiffies;
1118         rt->u.dst.output  = dn_output;
1119         rt->u.dst.input   = dn_rt_bug;
1120         rt->rt_flags      = flags;
1121         if (flags & RTCF_LOCAL)
1122                 rt->u.dst.input = dn_nsp_rx;
1123
1124         err = dn_rt_set_next_hop(rt, &res);
1125         if (err)
1126                 goto e_neighbour;
1127
1128         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1129         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1130
1131 done:
1132         if (neigh)
1133                 neigh_release(neigh);
1134         if (free_res)
1135                 dn_fib_res_put(&res);
1136         if (dev_out)
1137                 dev_put(dev_out);
1138 out:
1139         return err;
1140
1141 e_addr:
1142         err = -EADDRNOTAVAIL;
1143         goto done;
1144 e_inval:
1145         err = -EINVAL;
1146         goto done;
1147 e_nobufs:
1148         err = -ENOBUFS;
1149         goto done;
1150 e_neighbour:
1151         dst_free(&rt->u.dst);
1152         goto e_nobufs;
1153 }
1154
1155
1156 /*
1157  * N.B. The flags may be moved into the flowi at some future stage.
1158  */
1159 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1160 {
1161         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1162         struct dn_route *rt = NULL;
1163
1164         if (!(flags & MSG_TRYHARD)) {
1165                 rcu_read_lock_bh();
1166                 for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
1167                         rt = rcu_dereference(rt->u.rt_next)) {
1168                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1169                             (flp->fld_src == rt->fl.fld_src) &&
1170 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1171                             (flp->fld_fwmark == rt->fl.fld_fwmark) &&
1172 #endif
1173                             (rt->fl.iif == 0) &&
1174                             (rt->fl.oif == flp->oif)) {
1175                                 rt->u.dst.lastuse = jiffies;
1176                                 dst_hold(&rt->u.dst);
1177                                 rt->u.dst.__use++;
1178                                 rcu_read_unlock_bh();
1179                                 *pprt = &rt->u.dst;
1180                                 return 0;
1181                         }
1182                 }
1183                 rcu_read_unlock_bh();
1184         }
1185
1186         return dn_route_output_slow(pprt, flp, flags);
1187 }
1188
1189 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1190 {
1191         int err;
1192
1193         err = __dn_route_output_key(pprt, flp, flags);
1194         if (err == 0 && flp->proto) {
1195                 err = xfrm_lookup(pprt, flp, NULL, 0);
1196         }
1197         return err;
1198 }
1199
1200 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1201 {
1202         int err;
1203
1204         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1205         if (err == 0 && fl->proto) {
1206                 err = xfrm_lookup(pprt, fl, sk, !(flags & MSG_DONTWAIT));
1207         }
1208         return err;
1209 }
1210
1211 static int dn_route_input_slow(struct sk_buff *skb)
1212 {
1213         struct dn_route *rt = NULL;
1214         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1215         struct net_device *in_dev = skb->dev;
1216         struct net_device *out_dev = NULL;
1217         struct dn_dev *dn_db;
1218         struct neighbour *neigh = NULL;
1219         unsigned hash;
1220         int flags = 0;
1221         __le16 gateway = 0;
1222         __le16 local_src = 0;
1223         struct flowi fl = { .nl_u = { .dn_u = 
1224                                      { .daddr = cb->dst,
1225                                        .saddr = cb->src,
1226                                        .scope = RT_SCOPE_UNIVERSE,
1227 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1228                                        .fwmark = skb->nfmark
1229 #endif
1230                                     } },
1231                             .iif = skb->dev->ifindex };
1232         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1233         int err = -EINVAL;
1234         int free_res = 0;
1235
1236         dev_hold(in_dev);
1237
1238         if ((dn_db = in_dev->dn_ptr) == NULL)
1239                 goto out;
1240
1241         /* Zero source addresses are not allowed */
1242         if (fl.fld_src == 0)
1243                 goto out;
1244
1245         /*
1246          * In this case we've just received a packet from a source
1247          * outside ourselves pretending to come from us. We don't
1248          * allow it any further to prevent routing loops, spoofing and
1249          * other nasties. Loopback packets already have the dst attached
1250          * so this only affects packets which have originated elsewhere.
1251          */
1252         err  = -ENOTUNIQ;
1253         if (dn_dev_islocal(in_dev, cb->src))
1254                 goto out;
1255
1256         err = dn_fib_lookup(&fl, &res);
1257         if (err) {
1258                 if (err != -ESRCH)
1259                         goto out;
1260                 /*
1261                  * Is the destination us ?
1262                  */
1263                 if (!dn_dev_islocal(in_dev, cb->dst))
1264                         goto e_inval;
1265
1266                 res.type = RTN_LOCAL;
1267                 flags |= RTCF_DIRECTSRC;
1268         } else {
1269                 __le16 src_map = fl.fld_src;
1270                 free_res = 1;
1271
1272                 out_dev = DN_FIB_RES_DEV(res);
1273                 if (out_dev == NULL) {
1274                         if (net_ratelimit())
1275                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1276                                                  "No output device\n");
1277                         goto e_inval;
1278                 }
1279                 dev_hold(out_dev);
1280
1281                 if (res.r)
1282                         src_map = dn_fib_rules_policy(fl.fld_src, &res, &flags);
1283
1284                 gateway = DN_FIB_RES_GW(res);
1285                 if (res.type == RTN_NAT) {
1286                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1287                         dn_fib_res_put(&res);
1288                         free_res = 0;
1289                         if (dn_fib_lookup(&fl, &res))
1290                                 goto e_inval;
1291                         free_res = 1;
1292                         if (res.type != RTN_UNICAST)
1293                                 goto e_inval;
1294                         flags |= RTCF_DNAT;
1295                         gateway = fl.fld_dst;
1296                 }
1297                 fl.fld_src = src_map;
1298         }
1299
1300         switch(res.type) {
1301         case RTN_UNICAST:
1302                 /*
1303                  * Forwarding check here, we only check for forwarding
1304                  * being turned off, if you want to only forward intra
1305                  * area, its up to you to set the routing tables up
1306                  * correctly.
1307                  */
1308                 if (dn_db->parms.forwarding == 0)
1309                         goto e_inval;
1310
1311                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1312                         dn_fib_select_multipath(&fl, &res);
1313
1314                 /* 
1315                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1316                  * flag as a hint to set the intra-ethernet bit when
1317                  * forwarding. If we've got NAT in operation, we don't do
1318                  * this optimisation.
1319                  */
1320                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1321                         flags |= RTCF_DOREDIRECT;
1322
1323                 local_src = DN_FIB_RES_PREFSRC(res);
1324
1325         case RTN_BLACKHOLE:
1326         case RTN_UNREACHABLE:
1327                 break;
1328         case RTN_LOCAL:
1329                 flags |= RTCF_LOCAL;
1330                 fl.fld_src = cb->dst;
1331                 fl.fld_dst = cb->src;
1332
1333                 /* Routing tables gave us a gateway */
1334                 if (gateway)
1335                         goto make_route;
1336
1337                 /* Packet was intra-ethernet, so we know its on-link */
1338                 if (cb->rt_flags | DN_RT_F_IE) {
1339                         gateway = cb->src;
1340                         flags |= RTCF_DIRECTSRC;
1341                         goto make_route;
1342                 }
1343
1344                 /* Use the default router if there is one */
1345                 neigh = neigh_clone(dn_db->router);
1346                 if (neigh) {
1347                         gateway = ((struct dn_neigh *)neigh)->addr;
1348                         goto make_route;
1349                 }
1350
1351                 /* Close eyes and pray */
1352                 gateway = cb->src;
1353                 flags |= RTCF_DIRECTSRC;
1354                 goto make_route;
1355         default:
1356                 goto e_inval;
1357         }
1358
1359 make_route:
1360         rt = dst_alloc(&dn_dst_ops);
1361         if (rt == NULL)
1362                 goto e_nobufs;
1363
1364         rt->rt_saddr      = fl.fld_src;
1365         rt->rt_daddr      = fl.fld_dst;
1366         rt->rt_gateway    = fl.fld_dst;
1367         if (gateway)
1368                 rt->rt_gateway = gateway;
1369         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1370
1371         rt->rt_dst_map    = fl.fld_dst;
1372         rt->rt_src_map    = fl.fld_src;
1373
1374         rt->fl.fld_src    = cb->src;
1375         rt->fl.fld_dst    = cb->dst;
1376         rt->fl.oif        = 0;
1377         rt->fl.iif        = in_dev->ifindex;
1378         rt->fl.fld_fwmark = fl.fld_fwmark;
1379
1380         rt->u.dst.flags = DST_HOST;
1381         rt->u.dst.neighbour = neigh;
1382         rt->u.dst.dev = out_dev;
1383         rt->u.dst.lastuse = jiffies;
1384         rt->u.dst.output = dn_rt_bug;
1385         switch(res.type) {
1386                 case RTN_UNICAST:
1387                         rt->u.dst.input = dn_forward;
1388                         break;
1389                 case RTN_LOCAL:
1390                         rt->u.dst.output = dn_output;
1391                         rt->u.dst.input = dn_nsp_rx;
1392                         rt->u.dst.dev = in_dev;
1393                         flags |= RTCF_LOCAL;
1394                         break;
1395                 default:
1396                 case RTN_UNREACHABLE:
1397                 case RTN_BLACKHOLE:
1398                         rt->u.dst.input = dn_blackhole;
1399         }
1400         rt->rt_flags = flags;
1401         if (rt->u.dst.dev)
1402                 dev_hold(rt->u.dst.dev);
1403
1404         err = dn_rt_set_next_hop(rt, &res);
1405         if (err)
1406                 goto e_neighbour;
1407
1408         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1409         dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
1410
1411 done:
1412         if (neigh)
1413                 neigh_release(neigh);
1414         if (free_res)
1415                 dn_fib_res_put(&res);
1416         dev_put(in_dev);
1417         if (out_dev)
1418                 dev_put(out_dev);
1419 out:
1420         return err;
1421
1422 e_inval:
1423         err = -EINVAL;
1424         goto done;
1425
1426 e_nobufs:
1427         err = -ENOBUFS;
1428         goto done;
1429
1430 e_neighbour:
1431         dst_free(&rt->u.dst);
1432         goto done;
1433 }
1434
1435 int dn_route_input(struct sk_buff *skb)
1436 {
1437         struct dn_route *rt;
1438         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1439         unsigned hash = dn_hash(cb->src, cb->dst);
1440
1441         if (skb->dst)
1442                 return 0;
1443
1444         rcu_read_lock();
1445         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1446             rt = rcu_dereference(rt->u.rt_next)) {
1447                 if ((rt->fl.fld_src == cb->src) &&
1448                     (rt->fl.fld_dst == cb->dst) &&
1449                     (rt->fl.oif == 0) &&
1450 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1451                     (rt->fl.fld_fwmark == skb->nfmark) &&
1452 #endif
1453                     (rt->fl.iif == cb->iif)) {
1454                         rt->u.dst.lastuse = jiffies;
1455                         dst_hold(&rt->u.dst);
1456                         rt->u.dst.__use++;
1457                         rcu_read_unlock();
1458                         skb->dst = (struct dst_entry *)rt;
1459                         return 0;
1460                 }
1461         }
1462         rcu_read_unlock();
1463
1464         return dn_route_input_slow(skb);
1465 }
1466
1467 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1468                            int event, int nowait, unsigned int flags)
1469 {
1470         struct dn_route *rt = (struct dn_route *)skb->dst;
1471         struct rtmsg *r;
1472         struct nlmsghdr *nlh;
1473         unsigned char *b = skb->tail;
1474         struct rta_cacheinfo ci;
1475
1476         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1477         r = NLMSG_DATA(nlh);
1478         r->rtm_family = AF_DECnet;
1479         r->rtm_dst_len = 16;
1480         r->rtm_src_len = 0;
1481         r->rtm_tos = 0;
1482         r->rtm_table = RT_TABLE_MAIN;
1483         r->rtm_type = rt->rt_type;
1484         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1485         r->rtm_scope = RT_SCOPE_UNIVERSE;
1486         r->rtm_protocol = RTPROT_UNSPEC;
1487         if (rt->rt_flags & RTCF_NOTIFY)
1488                 r->rtm_flags |= RTM_F_NOTIFY;
1489         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1490         if (rt->fl.fld_src) {
1491                 r->rtm_src_len = 16;
1492                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1493         }
1494         if (rt->u.dst.dev)
1495                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1496         /*
1497          * Note to self - change this if input routes reverse direction when
1498          * they deal only with inputs and not with replies like they do
1499          * currently.
1500          */
1501         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1502         if (rt->rt_daddr != rt->rt_gateway)
1503                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1504         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1505                 goto rtattr_failure;
1506         ci.rta_lastuse = jiffies_to_clock_t(jiffies - rt->u.dst.lastuse);
1507         ci.rta_used     = rt->u.dst.__use;
1508         ci.rta_clntref  = atomic_read(&rt->u.dst.__refcnt);
1509         if (rt->u.dst.expires)
1510                 ci.rta_expires = jiffies_to_clock_t(rt->u.dst.expires - jiffies);
1511         else
1512                 ci.rta_expires = 0;
1513         ci.rta_error    = rt->u.dst.error;
1514         ci.rta_id       = ci.rta_ts = ci.rta_tsage = 0;
1515         RTA_PUT(skb, RTA_CACHEINFO, sizeof(ci), &ci);
1516         if (rt->fl.iif)
1517                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1518
1519         nlh->nlmsg_len = skb->tail - b;
1520         return skb->len;
1521
1522 nlmsg_failure:
1523 rtattr_failure:
1524         skb_trim(skb, b - skb->data);
1525         return -1;
1526 }
1527
1528 /*
1529  * This is called by both endnodes and routers now.
1530  */
1531 int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1532 {
1533         struct rtattr **rta = arg;
1534         struct rtmsg *rtm = NLMSG_DATA(nlh);
1535         struct dn_route *rt = NULL;
1536         struct dn_skb_cb *cb;
1537         int err;
1538         struct sk_buff *skb;
1539         struct flowi fl;
1540
1541         memset(&fl, 0, sizeof(fl));
1542         fl.proto = DNPROTO_NSP;
1543
1544         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1545         if (skb == NULL)
1546                 return -ENOBUFS;
1547         skb->mac.raw = skb->data;
1548         cb = DN_SKB_CB(skb);
1549
1550         if (rta[RTA_SRC-1])
1551                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1552         if (rta[RTA_DST-1])
1553                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1554         if (rta[RTA_IIF-1])
1555                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1556
1557         if (fl.iif) {
1558                 struct net_device *dev;
1559                 if ((dev = dev_get_by_index(fl.iif)) == NULL) {
1560                         kfree_skb(skb);
1561                         return -ENODEV;
1562                 }
1563                 if (!dev->dn_ptr) {
1564                         dev_put(dev);
1565                         kfree_skb(skb);
1566                         return -ENODEV;
1567                 }
1568                 skb->protocol = __constant_htons(ETH_P_DNA_RT);
1569                 skb->dev = dev;
1570                 cb->src = fl.fld_src;
1571                 cb->dst = fl.fld_dst;
1572                 local_bh_disable();
1573                 err = dn_route_input(skb);
1574                 local_bh_enable();
1575                 memset(cb, 0, sizeof(struct dn_skb_cb));
1576                 rt = (struct dn_route *)skb->dst;
1577                 if (!err && -rt->u.dst.error)
1578                         err = rt->u.dst.error;
1579         } else {
1580                 int oif = 0;
1581                 if (rta[RTA_OIF - 1])
1582                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1583                 fl.oif = oif;
1584                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1585         }
1586
1587         if (skb->dev)
1588                 dev_put(skb->dev);
1589         skb->dev = NULL;
1590         if (err)
1591                 goto out_free;
1592         skb->dst = &rt->u.dst;
1593         if (rtm->rtm_flags & RTM_F_NOTIFY)
1594                 rt->rt_flags |= RTCF_NOTIFY;
1595
1596         NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
1597
1598         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1599
1600         if (err == 0)
1601                 goto out_free;
1602         if (err < 0) {
1603                 err = -EMSGSIZE;
1604                 goto out_free;
1605         }
1606
1607         err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1608
1609         return err;
1610
1611 out_free:
1612         kfree_skb(skb);
1613         return err;
1614 }
1615
1616 /*
1617  * For routers, this is called from dn_fib_dump, but for endnodes its
1618  * called directly from the rtnetlink dispatch table.
1619  */
1620 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1621 {
1622         struct dn_route *rt;
1623         int h, s_h;
1624         int idx, s_idx;
1625
1626         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1627                 return -EINVAL;
1628         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1629                 return 0;
1630
1631         s_h = cb->args[0];
1632         s_idx = idx = cb->args[1];
1633         for(h = 0; h <= dn_rt_hash_mask; h++) {
1634                 if (h < s_h)
1635                         continue;
1636                 if (h > s_h)
1637                         s_idx = 0;
1638                 rcu_read_lock_bh();
1639                 for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
1640                         rt;
1641                         rt = rcu_dereference(rt->u.rt_next), idx++) {
1642                         if (idx < s_idx)
1643                                 continue;
1644                         skb->dst = dst_clone(&rt->u.dst);
1645                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1646                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE, 
1647                                         1, NLM_F_MULTI) <= 0) {
1648                                 dst_release(xchg(&skb->dst, NULL));
1649                                 rcu_read_unlock_bh();
1650                                 goto done;
1651                         }
1652                         dst_release(xchg(&skb->dst, NULL));
1653                 }
1654                 rcu_read_unlock_bh();
1655         }
1656
1657 done:
1658         cb->args[0] = h;
1659         cb->args[1] = idx;
1660         return skb->len;
1661 }
1662
1663 #ifdef CONFIG_PROC_FS
1664 struct dn_rt_cache_iter_state {
1665         int bucket;
1666 };
1667
1668 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1669 {
1670         struct dn_route *rt = NULL;
1671         struct dn_rt_cache_iter_state *s = seq->private;
1672
1673         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1674                 rcu_read_lock_bh();
1675                 rt = dn_rt_hash_table[s->bucket].chain;
1676                 if (rt)
1677                         break;
1678                 rcu_read_unlock_bh();
1679         }
1680         return rt;
1681 }
1682
1683 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1684 {
1685         struct dn_rt_cache_iter_state *s = rcu_dereference(seq->private);
1686
1687         rt = rt->u.rt_next;
1688         while(!rt) {
1689                 rcu_read_unlock_bh();
1690                 if (--s->bucket < 0)
1691                         break;
1692                 rcu_read_lock_bh();
1693                 rt = dn_rt_hash_table[s->bucket].chain;
1694         }
1695         return rt;
1696 }
1697
1698 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1699 {
1700         struct dn_route *rt = dn_rt_cache_get_first(seq);
1701
1702         if (rt) {
1703                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1704                         --*pos;
1705         }
1706         return *pos ? NULL : rt;
1707 }
1708
1709 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1710 {
1711         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1712         ++*pos;
1713         return rt;
1714 }
1715
1716 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1717 {
1718         if (v)
1719                 rcu_read_unlock_bh();
1720 }
1721
1722 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1723 {
1724         struct dn_route *rt = v;
1725         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1726
1727         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1728                         rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1729                         dn_addr2asc(dn_ntohs(rt->rt_daddr), buf1),
1730                         dn_addr2asc(dn_ntohs(rt->rt_saddr), buf2),
1731                         atomic_read(&rt->u.dst.__refcnt),
1732                         rt->u.dst.__use,
1733                         (int) dst_metric(&rt->u.dst, RTAX_RTT));
1734         return 0;
1735
1736
1737 static struct seq_operations dn_rt_cache_seq_ops = {
1738         .start  = dn_rt_cache_seq_start,
1739         .next   = dn_rt_cache_seq_next,
1740         .stop   = dn_rt_cache_seq_stop,
1741         .show   = dn_rt_cache_seq_show,
1742 };
1743
1744 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1745 {
1746         struct seq_file *seq;
1747         int rc = -ENOMEM;
1748         struct dn_rt_cache_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
1749
1750         if (!s)
1751                 goto out;
1752         rc = seq_open(file, &dn_rt_cache_seq_ops);
1753         if (rc)
1754                 goto out_kfree;
1755         seq             = file->private_data;
1756         seq->private    = s;
1757         memset(s, 0, sizeof(*s));
1758 out:
1759         return rc;
1760 out_kfree:
1761         kfree(s);
1762         goto out;
1763 }
1764
1765 static struct file_operations dn_rt_cache_seq_fops = {
1766         .owner   = THIS_MODULE,
1767         .open    = dn_rt_cache_seq_open,
1768         .read    = seq_read,
1769         .llseek  = seq_lseek,
1770         .release = seq_release_private,
1771 };
1772
1773 #endif /* CONFIG_PROC_FS */
1774
1775 void __init dn_route_init(void)
1776 {
1777         int i, goal, order;
1778
1779         dn_dst_ops.kmem_cachep = kmem_cache_create("dn_dst_cache",
1780                                                    sizeof(struct dn_route),
1781                                                    0, SLAB_HWCACHE_ALIGN,
1782                                                    NULL, NULL);
1783
1784         if (!dn_dst_ops.kmem_cachep)
1785                 panic("DECnet: Failed to allocate dn_dst_cache\n");
1786
1787         init_timer(&dn_route_timer);
1788         dn_route_timer.function = dn_dst_check_expire;
1789         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1790         add_timer(&dn_route_timer);
1791
1792         goal = num_physpages >> (26 - PAGE_SHIFT);
1793
1794         for(order = 0; (1UL << order) < goal; order++)
1795                 /* NOTHING */;
1796
1797         /*
1798          * Only want 1024 entries max, since the table is very, very unlikely
1799          * to be larger than that.
1800          */
1801         while(order && ((((1UL << order) * PAGE_SIZE) / 
1802                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1803                 order--;
1804
1805         do {
1806                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1807                         sizeof(struct dn_rt_hash_bucket);
1808                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1809                         dn_rt_hash_mask--;
1810                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1811                         __get_free_pages(GFP_ATOMIC, order);
1812         } while (dn_rt_hash_table == NULL && --order > 0);
1813
1814         if (!dn_rt_hash_table)
1815                 panic("Failed to allocate DECnet route cache hash table\n");
1816
1817         printk(KERN_INFO 
1818                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n", 
1819                 dn_rt_hash_mask, 
1820                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1821
1822         dn_rt_hash_mask--;
1823         for(i = 0; i <= dn_rt_hash_mask; i++) {
1824                 spin_lock_init(&dn_rt_hash_table[i].lock);
1825                 dn_rt_hash_table[i].chain = NULL;
1826         }
1827
1828         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1829
1830         proc_net_fops_create("decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1831 }
1832
1833 void __exit dn_route_cleanup(void)
1834 {
1835         del_timer(&dn_route_timer);
1836         dn_run_flush(0);
1837
1838         proc_net_remove("decnet_cache");
1839 }
1840