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 <linux/slab.h>
70 #include <net/sock.h>
71 #include <linux/mm.h>
72 #include <linux/proc_fs.h>
73 #include <linux/seq_file.h>
74 #include <linux/init.h>
75 #include <linux/rtnetlink.h>
76 #include <linux/string.h>
77 #include <linux/netfilter_decnet.h>
78 #include <linux/rcupdate.h>
79 #include <linux/times.h>
80 #include <linux/export.h>
81 #include <asm/errno.h>
82 #include <net/net_namespace.h>
83 #include <net/netlink.h>
84 #include <net/neighbour.h>
85 #include <net/dst.h>
86 #include <net/flow.h>
87 #include <net/fib_rules.h>
88 #include <net/dn.h>
89 #include <net/dn_dev.h>
90 #include <net/dn_nsp.h>
91 #include <net/dn_route.h>
92 #include <net/dn_neigh.h>
93 #include <net/dn_fib.h>
94 
95 struct dn_rt_hash_bucket
96 {
97 	struct dn_route __rcu *chain;
98 	spinlock_t lock;
99 };
100 
101 extern struct neigh_table dn_neigh_table;
102 
103 
104 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
105 
106 static const int dn_rt_min_delay = 2 * HZ;
107 static const int dn_rt_max_delay = 10 * HZ;
108 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
109 
110 static unsigned long dn_rt_deadline;
111 
112 static int dn_dst_gc(struct dst_ops *ops);
113 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
114 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);
115 static unsigned int dn_dst_mtu(const struct dst_entry *dst);
116 static void dn_dst_destroy(struct dst_entry *);
117 static void dn_dst_ifdown(struct dst_entry *, struct net_device *dev, int how);
118 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
119 static void dn_dst_link_failure(struct sk_buff *);
120 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
121 			       struct sk_buff *skb , u32 mtu);
122 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
123 			    struct sk_buff *skb);
124 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
125 					     struct sk_buff *skb,
126 					     const void *daddr);
127 static int dn_route_input(struct sk_buff *);
128 static void dn_run_flush(unsigned long dummy);
129 
130 static struct dn_rt_hash_bucket *dn_rt_hash_table;
131 static unsigned int dn_rt_hash_mask;
132 
133 static struct timer_list dn_route_timer;
134 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
135 int decnet_dst_gc_interval = 2;
136 
137 static struct dst_ops dn_dst_ops = {
138 	.family =		PF_DECnet,
139 	.gc_thresh =		128,
140 	.gc =			dn_dst_gc,
141 	.check =		dn_dst_check,
142 	.default_advmss =	dn_dst_default_advmss,
143 	.mtu =			dn_dst_mtu,
144 	.cow_metrics =		dst_cow_metrics_generic,
145 	.destroy =		dn_dst_destroy,
146 	.ifdown =		dn_dst_ifdown,
147 	.negative_advice =	dn_dst_negative_advice,
148 	.link_failure =		dn_dst_link_failure,
149 	.update_pmtu =		dn_dst_update_pmtu,
150 	.redirect =		dn_dst_redirect,
151 	.neigh_lookup =		dn_dst_neigh_lookup,
152 };
153 
dn_dst_destroy(struct dst_entry * dst)154 static void dn_dst_destroy(struct dst_entry *dst)
155 {
156 	struct dn_route *rt = (struct dn_route *) dst;
157 
158 	if (rt->n)
159 		neigh_release(rt->n);
160 	dst_destroy_metrics_generic(dst);
161 }
162 
dn_dst_ifdown(struct dst_entry * dst,struct net_device * dev,int how)163 static void dn_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int how)
164 {
165 	if (how) {
166 		struct dn_route *rt = (struct dn_route *) dst;
167 		struct neighbour *n = rt->n;
168 
169 		if (n && n->dev == dev) {
170 			n->dev = dev_net(dev)->loopback_dev;
171 			dev_hold(n->dev);
172 			dev_put(dev);
173 		}
174 	}
175 }
176 
dn_hash(__le16 src,__le16 dst)177 static __inline__ unsigned int dn_hash(__le16 src, __le16 dst)
178 {
179 	__u16 tmp = (__u16 __force)(src ^ dst);
180 	tmp ^= (tmp >> 3);
181 	tmp ^= (tmp >> 5);
182 	tmp ^= (tmp >> 10);
183 	return dn_rt_hash_mask & (unsigned int)tmp;
184 }
185 
dnrt_free(struct dn_route * rt)186 static inline void dnrt_free(struct dn_route *rt)
187 {
188 	call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
189 }
190 
dnrt_drop(struct dn_route * rt)191 static inline void dnrt_drop(struct dn_route *rt)
192 {
193 	dst_release(&rt->dst);
194 	call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
195 }
196 
dn_dst_check_expire(unsigned long dummy)197 static void dn_dst_check_expire(unsigned long dummy)
198 {
199 	int i;
200 	struct dn_route *rt;
201 	struct dn_route __rcu **rtp;
202 	unsigned long now = jiffies;
203 	unsigned long expire = 120 * HZ;
204 
205 	for (i = 0; i <= dn_rt_hash_mask; i++) {
206 		rtp = &dn_rt_hash_table[i].chain;
207 
208 		spin_lock(&dn_rt_hash_table[i].lock);
209 		while ((rt = rcu_dereference_protected(*rtp,
210 						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
211 			if (atomic_read(&rt->dst.__refcnt) ||
212 					(now - rt->dst.lastuse) < expire) {
213 				rtp = &rt->dst.dn_next;
214 				continue;
215 			}
216 			*rtp = rt->dst.dn_next;
217 			rt->dst.dn_next = NULL;
218 			dnrt_free(rt);
219 		}
220 		spin_unlock(&dn_rt_hash_table[i].lock);
221 
222 		if ((jiffies - now) > 0)
223 			break;
224 	}
225 
226 	mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
227 }
228 
dn_dst_gc(struct dst_ops * ops)229 static int dn_dst_gc(struct dst_ops *ops)
230 {
231 	struct dn_route *rt;
232 	struct dn_route __rcu **rtp;
233 	int i;
234 	unsigned long now = jiffies;
235 	unsigned long expire = 10 * HZ;
236 
237 	for (i = 0; i <= dn_rt_hash_mask; i++) {
238 
239 		spin_lock_bh(&dn_rt_hash_table[i].lock);
240 		rtp = &dn_rt_hash_table[i].chain;
241 
242 		while ((rt = rcu_dereference_protected(*rtp,
243 						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
244 			if (atomic_read(&rt->dst.__refcnt) ||
245 					(now - rt->dst.lastuse) < expire) {
246 				rtp = &rt->dst.dn_next;
247 				continue;
248 			}
249 			*rtp = rt->dst.dn_next;
250 			rt->dst.dn_next = NULL;
251 			dnrt_drop(rt);
252 			break;
253 		}
254 		spin_unlock_bh(&dn_rt_hash_table[i].lock);
255 	}
256 
257 	return 0;
258 }
259 
260 /*
261  * The decnet standards don't impose a particular minimum mtu, what they
262  * do insist on is that the routing layer accepts a datagram of at least
263  * 230 bytes long. Here we have to subtract the routing header length from
264  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
265  * assume the worst and use a long header size.
266  *
267  * We update both the mtu and the advertised mss (i.e. the segment size we
268  * advertise to the other end).
269  */
dn_dst_update_pmtu(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb,u32 mtu)270 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
271 			       struct sk_buff *skb, u32 mtu)
272 {
273 	struct dn_route *rt = (struct dn_route *) dst;
274 	struct neighbour *n = rt->n;
275 	u32 min_mtu = 230;
276 	struct dn_dev *dn;
277 
278 	dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
279 
280 	if (dn && dn->use_long == 0)
281 		min_mtu -= 6;
282 	else
283 		min_mtu -= 21;
284 
285 	if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
286 		if (!(dst_metric_locked(dst, RTAX_MTU))) {
287 			dst_metric_set(dst, RTAX_MTU, mtu);
288 			dst_set_expires(dst, dn_rt_mtu_expires);
289 		}
290 		if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
291 			u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
292 			u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
293 			if (!existing_mss || existing_mss > mss)
294 				dst_metric_set(dst, RTAX_ADVMSS, mss);
295 		}
296 	}
297 }
298 
dn_dst_redirect(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb)299 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
300 			    struct sk_buff *skb)
301 {
302 }
303 
304 /*
305  * When a route has been marked obsolete. (e.g. routing cache flush)
306  */
dn_dst_check(struct dst_entry * dst,__u32 cookie)307 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
308 {
309 	return NULL;
310 }
311 
dn_dst_negative_advice(struct dst_entry * dst)312 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
313 {
314 	dst_release(dst);
315 	return NULL;
316 }
317 
dn_dst_link_failure(struct sk_buff * skb)318 static void dn_dst_link_failure(struct sk_buff *skb)
319 {
320 }
321 
compare_keys(struct flowidn * fl1,struct flowidn * fl2)322 static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
323 {
324 	return ((fl1->daddr ^ fl2->daddr) |
325 		(fl1->saddr ^ fl2->saddr) |
326 		(fl1->flowidn_mark ^ fl2->flowidn_mark) |
327 		(fl1->flowidn_scope ^ fl2->flowidn_scope) |
328 		(fl1->flowidn_oif ^ fl2->flowidn_oif) |
329 		(fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
330 }
331 
dn_insert_route(struct dn_route * rt,unsigned int hash,struct dn_route ** rp)332 static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
333 {
334 	struct dn_route *rth;
335 	struct dn_route __rcu **rthp;
336 	unsigned long now = jiffies;
337 
338 	rthp = &dn_rt_hash_table[hash].chain;
339 
340 	spin_lock_bh(&dn_rt_hash_table[hash].lock);
341 	while ((rth = rcu_dereference_protected(*rthp,
342 						lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
343 		if (compare_keys(&rth->fld, &rt->fld)) {
344 			/* Put it first */
345 			*rthp = rth->dst.dn_next;
346 			rcu_assign_pointer(rth->dst.dn_next,
347 					   dn_rt_hash_table[hash].chain);
348 			rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
349 
350 			dst_use(&rth->dst, now);
351 			spin_unlock_bh(&dn_rt_hash_table[hash].lock);
352 
353 			dnrt_drop(rt);
354 			*rp = rth;
355 			return 0;
356 		}
357 		rthp = &rth->dst.dn_next;
358 	}
359 
360 	rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
361 	rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
362 
363 	dst_use(&rt->dst, now);
364 	spin_unlock_bh(&dn_rt_hash_table[hash].lock);
365 	*rp = rt;
366 	return 0;
367 }
368 
dn_run_flush(unsigned long dummy)369 static void dn_run_flush(unsigned long dummy)
370 {
371 	int i;
372 	struct dn_route *rt, *next;
373 
374 	for (i = 0; i < dn_rt_hash_mask; i++) {
375 		spin_lock_bh(&dn_rt_hash_table[i].lock);
376 
377 		if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
378 			goto nothing_to_declare;
379 
380 		for(; rt; rt = next) {
381 			next = rcu_dereference_raw(rt->dst.dn_next);
382 			RCU_INIT_POINTER(rt->dst.dn_next, NULL);
383 			dst_free((struct dst_entry *)rt);
384 		}
385 
386 nothing_to_declare:
387 		spin_unlock_bh(&dn_rt_hash_table[i].lock);
388 	}
389 }
390 
391 static DEFINE_SPINLOCK(dn_rt_flush_lock);
392 
dn_rt_cache_flush(int delay)393 void dn_rt_cache_flush(int delay)
394 {
395 	unsigned long now = jiffies;
396 	int user_mode = !in_interrupt();
397 
398 	if (delay < 0)
399 		delay = dn_rt_min_delay;
400 
401 	spin_lock_bh(&dn_rt_flush_lock);
402 
403 	if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
404 		long tmo = (long)(dn_rt_deadline - now);
405 
406 		if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
407 			tmo = 0;
408 
409 		if (delay > tmo)
410 			delay = tmo;
411 	}
412 
413 	if (delay <= 0) {
414 		spin_unlock_bh(&dn_rt_flush_lock);
415 		dn_run_flush(0);
416 		return;
417 	}
418 
419 	if (dn_rt_deadline == 0)
420 		dn_rt_deadline = now + dn_rt_max_delay;
421 
422 	dn_rt_flush_timer.expires = now + delay;
423 	add_timer(&dn_rt_flush_timer);
424 	spin_unlock_bh(&dn_rt_flush_lock);
425 }
426 
427 /**
428  * dn_return_short - Return a short packet to its sender
429  * @skb: The packet to return
430  *
431  */
dn_return_short(struct sk_buff * skb)432 static int dn_return_short(struct sk_buff *skb)
433 {
434 	struct dn_skb_cb *cb;
435 	unsigned char *ptr;
436 	__le16 *src;
437 	__le16 *dst;
438 
439 	/* Add back headers */
440 	skb_push(skb, skb->data - skb_network_header(skb));
441 
442 	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
443 		return NET_RX_DROP;
444 
445 	cb = DN_SKB_CB(skb);
446 	/* Skip packet length and point to flags */
447 	ptr = skb->data + 2;
448 	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
449 
450 	dst = (__le16 *)ptr;
451 	ptr += 2;
452 	src = (__le16 *)ptr;
453 	ptr += 2;
454 	*ptr = 0; /* Zero hop count */
455 
456 	swap(*src, *dst);
457 
458 	skb->pkt_type = PACKET_OUTGOING;
459 	dn_rt_finish_output(skb, NULL, NULL);
460 	return NET_RX_SUCCESS;
461 }
462 
463 /**
464  * dn_return_long - Return a long packet to its sender
465  * @skb: The long format packet to return
466  *
467  */
dn_return_long(struct sk_buff * skb)468 static int dn_return_long(struct sk_buff *skb)
469 {
470 	struct dn_skb_cb *cb;
471 	unsigned char *ptr;
472 	unsigned char *src_addr, *dst_addr;
473 	unsigned char tmp[ETH_ALEN];
474 
475 	/* Add back all headers */
476 	skb_push(skb, skb->data - skb_network_header(skb));
477 
478 	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
479 		return NET_RX_DROP;
480 
481 	cb = DN_SKB_CB(skb);
482 	/* Ignore packet length and point to flags */
483 	ptr = skb->data + 2;
484 
485 	/* Skip padding */
486 	if (*ptr & DN_RT_F_PF) {
487 		char padlen = (*ptr & ~DN_RT_F_PF);
488 		ptr += padlen;
489 	}
490 
491 	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
492 	ptr += 2;
493 	dst_addr = ptr;
494 	ptr += 8;
495 	src_addr = ptr;
496 	ptr += 6;
497 	*ptr = 0; /* Zero hop count */
498 
499 	/* Swap source and destination */
500 	memcpy(tmp, src_addr, ETH_ALEN);
501 	memcpy(src_addr, dst_addr, ETH_ALEN);
502 	memcpy(dst_addr, tmp, ETH_ALEN);
503 
504 	skb->pkt_type = PACKET_OUTGOING;
505 	dn_rt_finish_output(skb, dst_addr, src_addr);
506 	return NET_RX_SUCCESS;
507 }
508 
509 /**
510  * dn_route_rx_packet - Try and find a route for an incoming packet
511  * @skb: The packet to find a route for
512  *
513  * Returns: result of input function if route is found, error code otherwise
514  */
dn_route_rx_packet(struct sock * sk,struct sk_buff * skb)515 static int dn_route_rx_packet(struct sock *sk, struct sk_buff *skb)
516 {
517 	struct dn_skb_cb *cb;
518 	int err;
519 
520 	if ((err = dn_route_input(skb)) == 0)
521 		return dst_input(skb);
522 
523 	cb = DN_SKB_CB(skb);
524 	if (decnet_debug_level & 4) {
525 		char *devname = skb->dev ? skb->dev->name : "???";
526 
527 		printk(KERN_DEBUG
528 			"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
529 			(int)cb->rt_flags, devname, skb->len,
530 			le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
531 			err, skb->pkt_type);
532 	}
533 
534 	if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
535 		switch (cb->rt_flags & DN_RT_PKT_MSK) {
536 		case DN_RT_PKT_SHORT:
537 			return dn_return_short(skb);
538 		case DN_RT_PKT_LONG:
539 			return dn_return_long(skb);
540 		}
541 	}
542 
543 	kfree_skb(skb);
544 	return NET_RX_DROP;
545 }
546 
dn_route_rx_long(struct sk_buff * skb)547 static int dn_route_rx_long(struct sk_buff *skb)
548 {
549 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
550 	unsigned char *ptr = skb->data;
551 
552 	if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
553 		goto drop_it;
554 
555 	skb_pull(skb, 20);
556 	skb_reset_transport_header(skb);
557 
558 	/* Destination info */
559 	ptr += 2;
560 	cb->dst = dn_eth2dn(ptr);
561 	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
562 		goto drop_it;
563 	ptr += 6;
564 
565 
566 	/* Source info */
567 	ptr += 2;
568 	cb->src = dn_eth2dn(ptr);
569 	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
570 		goto drop_it;
571 	ptr += 6;
572 	/* Other junk */
573 	ptr++;
574 	cb->hops = *ptr++; /* Visit Count */
575 
576 	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, NULL, skb,
577 		       skb->dev, NULL,
578 		       dn_route_rx_packet);
579 
580 drop_it:
581 	kfree_skb(skb);
582 	return NET_RX_DROP;
583 }
584 
585 
586 
dn_route_rx_short(struct sk_buff * skb)587 static int dn_route_rx_short(struct sk_buff *skb)
588 {
589 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
590 	unsigned char *ptr = skb->data;
591 
592 	if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
593 		goto drop_it;
594 
595 	skb_pull(skb, 5);
596 	skb_reset_transport_header(skb);
597 
598 	cb->dst = *(__le16 *)ptr;
599 	ptr += 2;
600 	cb->src = *(__le16 *)ptr;
601 	ptr += 2;
602 	cb->hops = *ptr & 0x3f;
603 
604 	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, NULL, skb,
605 		       skb->dev, NULL,
606 		       dn_route_rx_packet);
607 
608 drop_it:
609 	kfree_skb(skb);
610 	return NET_RX_DROP;
611 }
612 
dn_route_discard(struct sock * sk,struct sk_buff * skb)613 static int dn_route_discard(struct sock *sk, struct sk_buff *skb)
614 {
615 	/*
616 	 * I know we drop the packet here, but thats considered success in
617 	 * this case
618 	 */
619 	kfree_skb(skb);
620 	return NET_RX_SUCCESS;
621 }
622 
dn_route_ptp_hello(struct sock * sk,struct sk_buff * skb)623 static int dn_route_ptp_hello(struct sock *sk, struct sk_buff *skb)
624 {
625 	dn_dev_hello(skb);
626 	dn_neigh_pointopoint_hello(skb);
627 	return NET_RX_SUCCESS;
628 }
629 
dn_route_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)630 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
631 {
632 	struct dn_skb_cb *cb;
633 	unsigned char flags = 0;
634 	__u16 len = le16_to_cpu(*(__le16 *)skb->data);
635 	struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
636 	unsigned char padlen = 0;
637 
638 	if (!net_eq(dev_net(dev), &init_net))
639 		goto dump_it;
640 
641 	if (dn == NULL)
642 		goto dump_it;
643 
644 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
645 		goto out;
646 
647 	if (!pskb_may_pull(skb, 3))
648 		goto dump_it;
649 
650 	skb_pull(skb, 2);
651 
652 	if (len > skb->len)
653 		goto dump_it;
654 
655 	skb_trim(skb, len);
656 
657 	flags = *skb->data;
658 
659 	cb = DN_SKB_CB(skb);
660 	cb->stamp = jiffies;
661 	cb->iif = dev->ifindex;
662 
663 	/*
664 	 * If we have padding, remove it.
665 	 */
666 	if (flags & DN_RT_F_PF) {
667 		padlen = flags & ~DN_RT_F_PF;
668 		if (!pskb_may_pull(skb, padlen + 1))
669 			goto dump_it;
670 		skb_pull(skb, padlen);
671 		flags = *skb->data;
672 	}
673 
674 	skb_reset_network_header(skb);
675 
676 	/*
677 	 * Weed out future version DECnet
678 	 */
679 	if (flags & DN_RT_F_VER)
680 		goto dump_it;
681 
682 	cb->rt_flags = flags;
683 
684 	if (decnet_debug_level & 1)
685 		printk(KERN_DEBUG
686 			"dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
687 			(int)flags, (dev) ? dev->name : "???", len, skb->len,
688 			padlen);
689 
690 	if (flags & DN_RT_PKT_CNTL) {
691 		if (unlikely(skb_linearize(skb)))
692 			goto dump_it;
693 
694 		switch (flags & DN_RT_CNTL_MSK) {
695 		case DN_RT_PKT_INIT:
696 			dn_dev_init_pkt(skb);
697 			break;
698 		case DN_RT_PKT_VERI:
699 			dn_dev_veri_pkt(skb);
700 			break;
701 		}
702 
703 		if (dn->parms.state != DN_DEV_S_RU)
704 			goto dump_it;
705 
706 		switch (flags & DN_RT_CNTL_MSK) {
707 		case DN_RT_PKT_HELO:
708 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
709 				       NULL, skb, skb->dev, NULL,
710 				       dn_route_ptp_hello);
711 
712 		case DN_RT_PKT_L1RT:
713 		case DN_RT_PKT_L2RT:
714 			return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
715 				       NULL, skb, skb->dev, NULL,
716 				       dn_route_discard);
717 		case DN_RT_PKT_ERTH:
718 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
719 				       NULL, skb, skb->dev, NULL,
720 				       dn_neigh_router_hello);
721 
722 		case DN_RT_PKT_EEDH:
723 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
724 				       NULL, skb, skb->dev, NULL,
725 				       dn_neigh_endnode_hello);
726 		}
727 	} else {
728 		if (dn->parms.state != DN_DEV_S_RU)
729 			goto dump_it;
730 
731 		skb_pull(skb, 1); /* Pull flags */
732 
733 		switch (flags & DN_RT_PKT_MSK) {
734 		case DN_RT_PKT_LONG:
735 			return dn_route_rx_long(skb);
736 		case DN_RT_PKT_SHORT:
737 			return dn_route_rx_short(skb);
738 		}
739 	}
740 
741 dump_it:
742 	kfree_skb(skb);
743 out:
744 	return NET_RX_DROP;
745 }
746 
dn_output(struct sock * sk,struct sk_buff * skb)747 static int dn_output(struct sock *sk, struct sk_buff *skb)
748 {
749 	struct dst_entry *dst = skb_dst(skb);
750 	struct dn_route *rt = (struct dn_route *)dst;
751 	struct net_device *dev = dst->dev;
752 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
753 
754 	int err = -EINVAL;
755 
756 	if (rt->n == NULL)
757 		goto error;
758 
759 	skb->dev = dev;
760 
761 	cb->src = rt->rt_saddr;
762 	cb->dst = rt->rt_daddr;
763 
764 	/*
765 	 * Always set the Intra-Ethernet bit on all outgoing packets
766 	 * originated on this node. Only valid flag from upper layers
767 	 * is return-to-sender-requested. Set hop count to 0 too.
768 	 */
769 	cb->rt_flags &= ~DN_RT_F_RQR;
770 	cb->rt_flags |= DN_RT_F_IE;
771 	cb->hops = 0;
772 
773 	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, sk, skb,
774 		       NULL, dev,
775 		       dn_to_neigh_output);
776 
777 error:
778 	net_dbg_ratelimited("dn_output: This should not happen\n");
779 
780 	kfree_skb(skb);
781 
782 	return err;
783 }
784 
dn_forward(struct sk_buff * skb)785 static int dn_forward(struct sk_buff *skb)
786 {
787 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
788 	struct dst_entry *dst = skb_dst(skb);
789 	struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
790 	struct dn_route *rt;
791 	int header_len;
792 #ifdef CONFIG_NETFILTER
793 	struct net_device *dev = skb->dev;
794 #endif
795 
796 	if (skb->pkt_type != PACKET_HOST)
797 		goto drop;
798 
799 	/* Ensure that we have enough space for headers */
800 	rt = (struct dn_route *)skb_dst(skb);
801 	header_len = dn_db->use_long ? 21 : 6;
802 	if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
803 		goto drop;
804 
805 	/*
806 	 * Hop count exceeded.
807 	 */
808 	if (++cb->hops > 30)
809 		goto drop;
810 
811 	skb->dev = rt->dst.dev;
812 
813 	/*
814 	 * If packet goes out same interface it came in on, then set
815 	 * the Intra-Ethernet bit. This has no effect for short
816 	 * packets, so we don't need to test for them here.
817 	 */
818 	cb->rt_flags &= ~DN_RT_F_IE;
819 	if (rt->rt_flags & RTCF_DOREDIRECT)
820 		cb->rt_flags |= DN_RT_F_IE;
821 
822 	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, NULL, skb,
823 		       dev, skb->dev,
824 		       dn_to_neigh_output);
825 
826 drop:
827 	kfree_skb(skb);
828 	return NET_RX_DROP;
829 }
830 
831 /*
832  * Used to catch bugs. This should never normally get
833  * called.
834  */
dn_rt_bug_sk(struct sock * sk,struct sk_buff * skb)835 static int dn_rt_bug_sk(struct sock *sk, struct sk_buff *skb)
836 {
837 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
838 
839 	net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
840 			    le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
841 
842 	kfree_skb(skb);
843 
844 	return NET_RX_DROP;
845 }
846 
dn_rt_bug(struct sk_buff * skb)847 static int dn_rt_bug(struct sk_buff *skb)
848 {
849 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
850 
851 	net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
852 			    le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
853 
854 	kfree_skb(skb);
855 
856 	return NET_RX_DROP;
857 }
858 
dn_dst_default_advmss(const struct dst_entry * dst)859 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
860 {
861 	return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
862 }
863 
dn_dst_mtu(const struct dst_entry * dst)864 static unsigned int dn_dst_mtu(const struct dst_entry *dst)
865 {
866 	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
867 
868 	return mtu ? : dst->dev->mtu;
869 }
870 
dn_dst_neigh_lookup(const struct dst_entry * dst,struct sk_buff * skb,const void * daddr)871 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
872 					     struct sk_buff *skb,
873 					     const void *daddr)
874 {
875 	return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
876 }
877 
dn_rt_set_next_hop(struct dn_route * rt,struct dn_fib_res * res)878 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
879 {
880 	struct dn_fib_info *fi = res->fi;
881 	struct net_device *dev = rt->dst.dev;
882 	unsigned int mss_metric;
883 	struct neighbour *n;
884 
885 	if (fi) {
886 		if (DN_FIB_RES_GW(*res) &&
887 		    DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
888 			rt->rt_gateway = DN_FIB_RES_GW(*res);
889 		dst_init_metrics(&rt->dst, fi->fib_metrics, true);
890 	}
891 	rt->rt_type = res->type;
892 
893 	if (dev != NULL && rt->n == NULL) {
894 		n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
895 		if (IS_ERR(n))
896 			return PTR_ERR(n);
897 		rt->n = n;
898 	}
899 
900 	if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
901 		dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
902 	mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
903 	if (mss_metric) {
904 		unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
905 		if (mss_metric > mss)
906 			dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
907 	}
908 	return 0;
909 }
910 
dn_match_addr(__le16 addr1,__le16 addr2)911 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
912 {
913 	__u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
914 	int match = 16;
915 	while(tmp) {
916 		tmp >>= 1;
917 		match--;
918 	}
919 	return match;
920 }
921 
dnet_select_source(const struct net_device * dev,__le16 daddr,int scope)922 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
923 {
924 	__le16 saddr = 0;
925 	struct dn_dev *dn_db;
926 	struct dn_ifaddr *ifa;
927 	int best_match = 0;
928 	int ret;
929 
930 	rcu_read_lock();
931 	dn_db = rcu_dereference(dev->dn_ptr);
932 	for (ifa = rcu_dereference(dn_db->ifa_list);
933 	     ifa != NULL;
934 	     ifa = rcu_dereference(ifa->ifa_next)) {
935 		if (ifa->ifa_scope > scope)
936 			continue;
937 		if (!daddr) {
938 			saddr = ifa->ifa_local;
939 			break;
940 		}
941 		ret = dn_match_addr(daddr, ifa->ifa_local);
942 		if (ret > best_match)
943 			saddr = ifa->ifa_local;
944 		if (best_match == 0)
945 			saddr = ifa->ifa_local;
946 	}
947 	rcu_read_unlock();
948 
949 	return saddr;
950 }
951 
__dn_fib_res_prefsrc(struct dn_fib_res * res)952 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
953 {
954 	return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
955 }
956 
dn_fib_rules_map_destination(__le16 daddr,struct dn_fib_res * res)957 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
958 {
959 	__le16 mask = dnet_make_mask(res->prefixlen);
960 	return (daddr&~mask)|res->fi->fib_nh->nh_gw;
961 }
962 
dn_route_output_slow(struct dst_entry ** pprt,const struct flowidn * oldflp,int try_hard)963 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
964 {
965 	struct flowidn fld = {
966 		.daddr = oldflp->daddr,
967 		.saddr = oldflp->saddr,
968 		.flowidn_scope = RT_SCOPE_UNIVERSE,
969 		.flowidn_mark = oldflp->flowidn_mark,
970 		.flowidn_iif = LOOPBACK_IFINDEX,
971 		.flowidn_oif = oldflp->flowidn_oif,
972 	};
973 	struct dn_route *rt = NULL;
974 	struct net_device *dev_out = NULL, *dev;
975 	struct neighbour *neigh = NULL;
976 	unsigned int hash;
977 	unsigned int flags = 0;
978 	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
979 	int err;
980 	int free_res = 0;
981 	__le16 gateway = 0;
982 
983 	if (decnet_debug_level & 16)
984 		printk(KERN_DEBUG
985 		       "dn_route_output_slow: dst=%04x src=%04x mark=%d"
986 		       " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
987 		       le16_to_cpu(oldflp->saddr),
988 		       oldflp->flowidn_mark, LOOPBACK_IFINDEX,
989 		       oldflp->flowidn_oif);
990 
991 	/* If we have an output interface, verify its a DECnet device */
992 	if (oldflp->flowidn_oif) {
993 		dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
994 		err = -ENODEV;
995 		if (dev_out && dev_out->dn_ptr == NULL) {
996 			dev_put(dev_out);
997 			dev_out = NULL;
998 		}
999 		if (dev_out == NULL)
1000 			goto out;
1001 	}
1002 
1003 	/* If we have a source address, verify that its a local address */
1004 	if (oldflp->saddr) {
1005 		err = -EADDRNOTAVAIL;
1006 
1007 		if (dev_out) {
1008 			if (dn_dev_islocal(dev_out, oldflp->saddr))
1009 				goto source_ok;
1010 			dev_put(dev_out);
1011 			goto out;
1012 		}
1013 		rcu_read_lock();
1014 		for_each_netdev_rcu(&init_net, dev) {
1015 			if (!dev->dn_ptr)
1016 				continue;
1017 			if (!dn_dev_islocal(dev, oldflp->saddr))
1018 				continue;
1019 			if ((dev->flags & IFF_LOOPBACK) &&
1020 			    oldflp->daddr &&
1021 			    !dn_dev_islocal(dev, oldflp->daddr))
1022 				continue;
1023 
1024 			dev_out = dev;
1025 			break;
1026 		}
1027 		rcu_read_unlock();
1028 		if (dev_out == NULL)
1029 			goto out;
1030 		dev_hold(dev_out);
1031 source_ok:
1032 		;
1033 	}
1034 
1035 	/* No destination? Assume its local */
1036 	if (!fld.daddr) {
1037 		fld.daddr = fld.saddr;
1038 
1039 		err = -EADDRNOTAVAIL;
1040 		if (dev_out)
1041 			dev_put(dev_out);
1042 		dev_out = init_net.loopback_dev;
1043 		dev_hold(dev_out);
1044 		if (!fld.daddr) {
1045 			fld.daddr =
1046 			fld.saddr = dnet_select_source(dev_out, 0,
1047 						       RT_SCOPE_HOST);
1048 			if (!fld.daddr)
1049 				goto out;
1050 		}
1051 		fld.flowidn_oif = LOOPBACK_IFINDEX;
1052 		res.type = RTN_LOCAL;
1053 		goto make_route;
1054 	}
1055 
1056 	if (decnet_debug_level & 16)
1057 		printk(KERN_DEBUG
1058 		       "dn_route_output_slow: initial checks complete."
1059 		       " dst=%04x src=%04x oif=%d try_hard=%d\n",
1060 		       le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1061 		       fld.flowidn_oif, try_hard);
1062 
1063 	/*
1064 	 * N.B. If the kernel is compiled without router support then
1065 	 * dn_fib_lookup() will evaluate to non-zero so this if () block
1066 	 * will always be executed.
1067 	 */
1068 	err = -ESRCH;
1069 	if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
1070 		struct dn_dev *dn_db;
1071 		if (err != -ESRCH)
1072 			goto out;
1073 		/*
1074 		 * Here the fallback is basically the standard algorithm for
1075 		 * routing in endnodes which is described in the DECnet routing
1076 		 * docs
1077 		 *
1078 		 * If we are not trying hard, look in neighbour cache.
1079 		 * The result is tested to ensure that if a specific output
1080 		 * device/source address was requested, then we honour that
1081 		 * here
1082 		 */
1083 		if (!try_hard) {
1084 			neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1085 			if (neigh) {
1086 				if ((oldflp->flowidn_oif &&
1087 				    (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
1088 				    (oldflp->saddr &&
1089 				    (!dn_dev_islocal(neigh->dev,
1090 						     oldflp->saddr)))) {
1091 					neigh_release(neigh);
1092 					neigh = NULL;
1093 				} else {
1094 					if (dev_out)
1095 						dev_put(dev_out);
1096 					if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1097 						dev_out = init_net.loopback_dev;
1098 						res.type = RTN_LOCAL;
1099 					} else {
1100 						dev_out = neigh->dev;
1101 					}
1102 					dev_hold(dev_out);
1103 					goto select_source;
1104 				}
1105 			}
1106 		}
1107 
1108 		/* Not there? Perhaps its a local address */
1109 		if (dev_out == NULL)
1110 			dev_out = dn_dev_get_default();
1111 		err = -ENODEV;
1112 		if (dev_out == NULL)
1113 			goto out;
1114 		dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1115 		/* Possible improvement - check all devices for local addr */
1116 		if (dn_dev_islocal(dev_out, fld.daddr)) {
1117 			dev_put(dev_out);
1118 			dev_out = init_net.loopback_dev;
1119 			dev_hold(dev_out);
1120 			res.type = RTN_LOCAL;
1121 			goto select_source;
1122 		}
1123 		/* Not local either.... try sending it to the default router */
1124 		neigh = neigh_clone(dn_db->router);
1125 		BUG_ON(neigh && neigh->dev != dev_out);
1126 
1127 		/* Ok then, we assume its directly connected and move on */
1128 select_source:
1129 		if (neigh)
1130 			gateway = ((struct dn_neigh *)neigh)->addr;
1131 		if (gateway == 0)
1132 			gateway = fld.daddr;
1133 		if (fld.saddr == 0) {
1134 			fld.saddr = dnet_select_source(dev_out, gateway,
1135 						       res.type == RTN_LOCAL ?
1136 						       RT_SCOPE_HOST :
1137 						       RT_SCOPE_LINK);
1138 			if (fld.saddr == 0 && res.type != RTN_LOCAL)
1139 				goto e_addr;
1140 		}
1141 		fld.flowidn_oif = dev_out->ifindex;
1142 		goto make_route;
1143 	}
1144 	free_res = 1;
1145 
1146 	if (res.type == RTN_NAT)
1147 		goto e_inval;
1148 
1149 	if (res.type == RTN_LOCAL) {
1150 		if (!fld.saddr)
1151 			fld.saddr = fld.daddr;
1152 		if (dev_out)
1153 			dev_put(dev_out);
1154 		dev_out = init_net.loopback_dev;
1155 		dev_hold(dev_out);
1156 		fld.flowidn_oif = dev_out->ifindex;
1157 		if (res.fi)
1158 			dn_fib_info_put(res.fi);
1159 		res.fi = NULL;
1160 		goto make_route;
1161 	}
1162 
1163 	if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1164 		dn_fib_select_multipath(&fld, &res);
1165 
1166 	/*
1167 	 * We could add some logic to deal with default routes here and
1168 	 * get rid of some of the special casing above.
1169 	 */
1170 
1171 	if (!fld.saddr)
1172 		fld.saddr = DN_FIB_RES_PREFSRC(res);
1173 
1174 	if (dev_out)
1175 		dev_put(dev_out);
1176 	dev_out = DN_FIB_RES_DEV(res);
1177 	dev_hold(dev_out);
1178 	fld.flowidn_oif = dev_out->ifindex;
1179 	gateway = DN_FIB_RES_GW(res);
1180 
1181 make_route:
1182 	if (dev_out->flags & IFF_LOOPBACK)
1183 		flags |= RTCF_LOCAL;
1184 
1185 	rt = dst_alloc(&dn_dst_ops, dev_out, 1, DST_OBSOLETE_NONE, DST_HOST);
1186 	if (rt == NULL)
1187 		goto e_nobufs;
1188 
1189 	memset(&rt->fld, 0, sizeof(rt->fld));
1190 	rt->fld.saddr        = oldflp->saddr;
1191 	rt->fld.daddr        = oldflp->daddr;
1192 	rt->fld.flowidn_oif  = oldflp->flowidn_oif;
1193 	rt->fld.flowidn_iif  = 0;
1194 	rt->fld.flowidn_mark = oldflp->flowidn_mark;
1195 
1196 	rt->rt_saddr      = fld.saddr;
1197 	rt->rt_daddr      = fld.daddr;
1198 	rt->rt_gateway    = gateway ? gateway : fld.daddr;
1199 	rt->rt_local_src  = fld.saddr;
1200 
1201 	rt->rt_dst_map    = fld.daddr;
1202 	rt->rt_src_map    = fld.saddr;
1203 
1204 	rt->n = neigh;
1205 	neigh = NULL;
1206 
1207 	rt->dst.lastuse = jiffies;
1208 	rt->dst.output  = dn_output;
1209 	rt->dst.input   = dn_rt_bug;
1210 	rt->rt_flags      = flags;
1211 	if (flags & RTCF_LOCAL)
1212 		rt->dst.input = dn_nsp_rx;
1213 
1214 	err = dn_rt_set_next_hop(rt, &res);
1215 	if (err)
1216 		goto e_neighbour;
1217 
1218 	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1219 	dn_insert_route(rt, hash, (struct dn_route **)pprt);
1220 
1221 done:
1222 	if (neigh)
1223 		neigh_release(neigh);
1224 	if (free_res)
1225 		dn_fib_res_put(&res);
1226 	if (dev_out)
1227 		dev_put(dev_out);
1228 out:
1229 	return err;
1230 
1231 e_addr:
1232 	err = -EADDRNOTAVAIL;
1233 	goto done;
1234 e_inval:
1235 	err = -EINVAL;
1236 	goto done;
1237 e_nobufs:
1238 	err = -ENOBUFS;
1239 	goto done;
1240 e_neighbour:
1241 	dst_free(&rt->dst);
1242 	goto e_nobufs;
1243 }
1244 
1245 
1246 /*
1247  * N.B. The flags may be moved into the flowi at some future stage.
1248  */
__dn_route_output_key(struct dst_entry ** pprt,const struct flowidn * flp,int flags)1249 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowidn *flp, int flags)
1250 {
1251 	unsigned int hash = dn_hash(flp->saddr, flp->daddr);
1252 	struct dn_route *rt = NULL;
1253 
1254 	if (!(flags & MSG_TRYHARD)) {
1255 		rcu_read_lock_bh();
1256 		for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1257 			rt = rcu_dereference_bh(rt->dst.dn_next)) {
1258 			if ((flp->daddr == rt->fld.daddr) &&
1259 			    (flp->saddr == rt->fld.saddr) &&
1260 			    (flp->flowidn_mark == rt->fld.flowidn_mark) &&
1261 			    dn_is_output_route(rt) &&
1262 			    (rt->fld.flowidn_oif == flp->flowidn_oif)) {
1263 				dst_use(&rt->dst, jiffies);
1264 				rcu_read_unlock_bh();
1265 				*pprt = &rt->dst;
1266 				return 0;
1267 			}
1268 		}
1269 		rcu_read_unlock_bh();
1270 	}
1271 
1272 	return dn_route_output_slow(pprt, flp, flags);
1273 }
1274 
dn_route_output_key(struct dst_entry ** pprt,struct flowidn * flp,int flags)1275 static int dn_route_output_key(struct dst_entry **pprt, struct flowidn *flp, int flags)
1276 {
1277 	int err;
1278 
1279 	err = __dn_route_output_key(pprt, flp, flags);
1280 	if (err == 0 && flp->flowidn_proto) {
1281 		*pprt = xfrm_lookup(&init_net, *pprt,
1282 				    flowidn_to_flowi(flp), NULL, 0);
1283 		if (IS_ERR(*pprt)) {
1284 			err = PTR_ERR(*pprt);
1285 			*pprt = NULL;
1286 		}
1287 	}
1288 	return err;
1289 }
1290 
dn_route_output_sock(struct dst_entry __rcu ** pprt,struct flowidn * fl,struct sock * sk,int flags)1291 int dn_route_output_sock(struct dst_entry __rcu **pprt, struct flowidn *fl, struct sock *sk, int flags)
1292 {
1293 	int err;
1294 
1295 	err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1296 	if (err == 0 && fl->flowidn_proto) {
1297 		*pprt = xfrm_lookup(&init_net, *pprt,
1298 				    flowidn_to_flowi(fl), sk, 0);
1299 		if (IS_ERR(*pprt)) {
1300 			err = PTR_ERR(*pprt);
1301 			*pprt = NULL;
1302 		}
1303 	}
1304 	return err;
1305 }
1306 
dn_route_input_slow(struct sk_buff * skb)1307 static int dn_route_input_slow(struct sk_buff *skb)
1308 {
1309 	struct dn_route *rt = NULL;
1310 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
1311 	struct net_device *in_dev = skb->dev;
1312 	struct net_device *out_dev = NULL;
1313 	struct dn_dev *dn_db;
1314 	struct neighbour *neigh = NULL;
1315 	unsigned int hash;
1316 	int flags = 0;
1317 	__le16 gateway = 0;
1318 	__le16 local_src = 0;
1319 	struct flowidn fld = {
1320 		.daddr = cb->dst,
1321 		.saddr = cb->src,
1322 		.flowidn_scope = RT_SCOPE_UNIVERSE,
1323 		.flowidn_mark = skb->mark,
1324 		.flowidn_iif = skb->dev->ifindex,
1325 	};
1326 	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1327 	int err = -EINVAL;
1328 	int free_res = 0;
1329 
1330 	dev_hold(in_dev);
1331 
1332 	if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1333 		goto out;
1334 
1335 	/* Zero source addresses are not allowed */
1336 	if (fld.saddr == 0)
1337 		goto out;
1338 
1339 	/*
1340 	 * In this case we've just received a packet from a source
1341 	 * outside ourselves pretending to come from us. We don't
1342 	 * allow it any further to prevent routing loops, spoofing and
1343 	 * other nasties. Loopback packets already have the dst attached
1344 	 * so this only affects packets which have originated elsewhere.
1345 	 */
1346 	err  = -ENOTUNIQ;
1347 	if (dn_dev_islocal(in_dev, cb->src))
1348 		goto out;
1349 
1350 	err = dn_fib_lookup(&fld, &res);
1351 	if (err) {
1352 		if (err != -ESRCH)
1353 			goto out;
1354 		/*
1355 		 * Is the destination us ?
1356 		 */
1357 		if (!dn_dev_islocal(in_dev, cb->dst))
1358 			goto e_inval;
1359 
1360 		res.type = RTN_LOCAL;
1361 	} else {
1362 		__le16 src_map = fld.saddr;
1363 		free_res = 1;
1364 
1365 		out_dev = DN_FIB_RES_DEV(res);
1366 		if (out_dev == NULL) {
1367 			net_crit_ratelimited("Bug in dn_route_input_slow() No output device\n");
1368 			goto e_inval;
1369 		}
1370 		dev_hold(out_dev);
1371 
1372 		if (res.r)
1373 			src_map = fld.saddr; /* no NAT support for now */
1374 
1375 		gateway = DN_FIB_RES_GW(res);
1376 		if (res.type == RTN_NAT) {
1377 			fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
1378 			dn_fib_res_put(&res);
1379 			free_res = 0;
1380 			if (dn_fib_lookup(&fld, &res))
1381 				goto e_inval;
1382 			free_res = 1;
1383 			if (res.type != RTN_UNICAST)
1384 				goto e_inval;
1385 			flags |= RTCF_DNAT;
1386 			gateway = fld.daddr;
1387 		}
1388 		fld.saddr = src_map;
1389 	}
1390 
1391 	switch(res.type) {
1392 	case RTN_UNICAST:
1393 		/*
1394 		 * Forwarding check here, we only check for forwarding
1395 		 * being turned off, if you want to only forward intra
1396 		 * area, its up to you to set the routing tables up
1397 		 * correctly.
1398 		 */
1399 		if (dn_db->parms.forwarding == 0)
1400 			goto e_inval;
1401 
1402 		if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1403 			dn_fib_select_multipath(&fld, &res);
1404 
1405 		/*
1406 		 * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1407 		 * flag as a hint to set the intra-ethernet bit when
1408 		 * forwarding. If we've got NAT in operation, we don't do
1409 		 * this optimisation.
1410 		 */
1411 		if (out_dev == in_dev && !(flags & RTCF_NAT))
1412 			flags |= RTCF_DOREDIRECT;
1413 
1414 		local_src = DN_FIB_RES_PREFSRC(res);
1415 
1416 	case RTN_BLACKHOLE:
1417 	case RTN_UNREACHABLE:
1418 		break;
1419 	case RTN_LOCAL:
1420 		flags |= RTCF_LOCAL;
1421 		fld.saddr = cb->dst;
1422 		fld.daddr = cb->src;
1423 
1424 		/* Routing tables gave us a gateway */
1425 		if (gateway)
1426 			goto make_route;
1427 
1428 		/* Packet was intra-ethernet, so we know its on-link */
1429 		if (cb->rt_flags & DN_RT_F_IE) {
1430 			gateway = cb->src;
1431 			goto make_route;
1432 		}
1433 
1434 		/* Use the default router if there is one */
1435 		neigh = neigh_clone(dn_db->router);
1436 		if (neigh) {
1437 			gateway = ((struct dn_neigh *)neigh)->addr;
1438 			goto make_route;
1439 		}
1440 
1441 		/* Close eyes and pray */
1442 		gateway = cb->src;
1443 		goto make_route;
1444 	default:
1445 		goto e_inval;
1446 	}
1447 
1448 make_route:
1449 	rt = dst_alloc(&dn_dst_ops, out_dev, 0, DST_OBSOLETE_NONE, DST_HOST);
1450 	if (rt == NULL)
1451 		goto e_nobufs;
1452 
1453 	memset(&rt->fld, 0, sizeof(rt->fld));
1454 	rt->rt_saddr      = fld.saddr;
1455 	rt->rt_daddr      = fld.daddr;
1456 	rt->rt_gateway    = fld.daddr;
1457 	if (gateway)
1458 		rt->rt_gateway = gateway;
1459 	rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1460 
1461 	rt->rt_dst_map    = fld.daddr;
1462 	rt->rt_src_map    = fld.saddr;
1463 
1464 	rt->fld.saddr        = cb->src;
1465 	rt->fld.daddr        = cb->dst;
1466 	rt->fld.flowidn_oif  = 0;
1467 	rt->fld.flowidn_iif  = in_dev->ifindex;
1468 	rt->fld.flowidn_mark = fld.flowidn_mark;
1469 
1470 	rt->n = neigh;
1471 	rt->dst.lastuse = jiffies;
1472 	rt->dst.output = dn_rt_bug_sk;
1473 	switch (res.type) {
1474 	case RTN_UNICAST:
1475 		rt->dst.input = dn_forward;
1476 		break;
1477 	case RTN_LOCAL:
1478 		rt->dst.output = dn_output;
1479 		rt->dst.input = dn_nsp_rx;
1480 		rt->dst.dev = in_dev;
1481 		flags |= RTCF_LOCAL;
1482 		break;
1483 	default:
1484 	case RTN_UNREACHABLE:
1485 	case RTN_BLACKHOLE:
1486 		rt->dst.input = dst_discard;
1487 	}
1488 	rt->rt_flags = flags;
1489 
1490 	err = dn_rt_set_next_hop(rt, &res);
1491 	if (err)
1492 		goto e_neighbour;
1493 
1494 	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1495 	dn_insert_route(rt, hash, &rt);
1496 	skb_dst_set(skb, &rt->dst);
1497 
1498 done:
1499 	if (neigh)
1500 		neigh_release(neigh);
1501 	if (free_res)
1502 		dn_fib_res_put(&res);
1503 	dev_put(in_dev);
1504 	if (out_dev)
1505 		dev_put(out_dev);
1506 out:
1507 	return err;
1508 
1509 e_inval:
1510 	err = -EINVAL;
1511 	goto done;
1512 
1513 e_nobufs:
1514 	err = -ENOBUFS;
1515 	goto done;
1516 
1517 e_neighbour:
1518 	dst_free(&rt->dst);
1519 	goto done;
1520 }
1521 
dn_route_input(struct sk_buff * skb)1522 static int dn_route_input(struct sk_buff *skb)
1523 {
1524 	struct dn_route *rt;
1525 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
1526 	unsigned int hash = dn_hash(cb->src, cb->dst);
1527 
1528 	if (skb_dst(skb))
1529 		return 0;
1530 
1531 	rcu_read_lock();
1532 	for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1533 	    rt = rcu_dereference(rt->dst.dn_next)) {
1534 		if ((rt->fld.saddr == cb->src) &&
1535 		    (rt->fld.daddr == cb->dst) &&
1536 		    (rt->fld.flowidn_oif == 0) &&
1537 		    (rt->fld.flowidn_mark == skb->mark) &&
1538 		    (rt->fld.flowidn_iif == cb->iif)) {
1539 			dst_use(&rt->dst, jiffies);
1540 			rcu_read_unlock();
1541 			skb_dst_set(skb, (struct dst_entry *)rt);
1542 			return 0;
1543 		}
1544 	}
1545 	rcu_read_unlock();
1546 
1547 	return dn_route_input_slow(skb);
1548 }
1549 
dn_rt_fill_info(struct sk_buff * skb,u32 portid,u32 seq,int event,int nowait,unsigned int flags)1550 static int dn_rt_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
1551 			   int event, int nowait, unsigned int flags)
1552 {
1553 	struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1554 	struct rtmsg *r;
1555 	struct nlmsghdr *nlh;
1556 	long expires;
1557 
1558 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
1559 	if (!nlh)
1560 		return -EMSGSIZE;
1561 
1562 	r = nlmsg_data(nlh);
1563 	r->rtm_family = AF_DECnet;
1564 	r->rtm_dst_len = 16;
1565 	r->rtm_src_len = 0;
1566 	r->rtm_tos = 0;
1567 	r->rtm_table = RT_TABLE_MAIN;
1568 	r->rtm_type = rt->rt_type;
1569 	r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1570 	r->rtm_scope = RT_SCOPE_UNIVERSE;
1571 	r->rtm_protocol = RTPROT_UNSPEC;
1572 
1573 	if (rt->rt_flags & RTCF_NOTIFY)
1574 		r->rtm_flags |= RTM_F_NOTIFY;
1575 
1576 	if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN) < 0 ||
1577 	    nla_put_le16(skb, RTA_DST, rt->rt_daddr) < 0)
1578 		goto errout;
1579 
1580 	if (rt->fld.saddr) {
1581 		r->rtm_src_len = 16;
1582 		if (nla_put_le16(skb, RTA_SRC, rt->fld.saddr) < 0)
1583 			goto errout;
1584 	}
1585 	if (rt->dst.dev &&
1586 	    nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex) < 0)
1587 		goto errout;
1588 
1589 	/*
1590 	 * Note to self - change this if input routes reverse direction when
1591 	 * they deal only with inputs and not with replies like they do
1592 	 * currently.
1593 	 */
1594 	if (nla_put_le16(skb, RTA_PREFSRC, rt->rt_local_src) < 0)
1595 		goto errout;
1596 
1597 	if (rt->rt_daddr != rt->rt_gateway &&
1598 	    nla_put_le16(skb, RTA_GATEWAY, rt->rt_gateway) < 0)
1599 		goto errout;
1600 
1601 	if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1602 		goto errout;
1603 
1604 	expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1605 	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
1606 			       rt->dst.error) < 0)
1607 		goto errout;
1608 
1609 	if (dn_is_input_route(rt) &&
1610 	    nla_put_u32(skb, RTA_IIF, rt->fld.flowidn_iif) < 0)
1611 		goto errout;
1612 
1613 	nlmsg_end(skb, nlh);
1614 	return 0;
1615 
1616 errout:
1617 	nlmsg_cancel(skb, nlh);
1618 	return -EMSGSIZE;
1619 }
1620 
1621 const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
1622 	[RTA_DST]		= { .type = NLA_U16 },
1623 	[RTA_SRC]		= { .type = NLA_U16 },
1624 	[RTA_IIF]		= { .type = NLA_U32 },
1625 	[RTA_OIF]		= { .type = NLA_U32 },
1626 	[RTA_GATEWAY]		= { .type = NLA_U16 },
1627 	[RTA_PRIORITY]		= { .type = NLA_U32 },
1628 	[RTA_PREFSRC]		= { .type = NLA_U16 },
1629 	[RTA_METRICS]		= { .type = NLA_NESTED },
1630 	[RTA_MULTIPATH]		= { .type = NLA_NESTED },
1631 	[RTA_TABLE]		= { .type = NLA_U32 },
1632 	[RTA_MARK]		= { .type = NLA_U32 },
1633 };
1634 
1635 /*
1636  * This is called by both endnodes and routers now.
1637  */
dn_cache_getroute(struct sk_buff * in_skb,struct nlmsghdr * nlh)1638 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh)
1639 {
1640 	struct net *net = sock_net(in_skb->sk);
1641 	struct rtmsg *rtm = nlmsg_data(nlh);
1642 	struct dn_route *rt = NULL;
1643 	struct dn_skb_cb *cb;
1644 	int err;
1645 	struct sk_buff *skb;
1646 	struct flowidn fld;
1647 	struct nlattr *tb[RTA_MAX+1];
1648 
1649 	if (!net_eq(net, &init_net))
1650 		return -EINVAL;
1651 
1652 	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy);
1653 	if (err < 0)
1654 		return err;
1655 
1656 	memset(&fld, 0, sizeof(fld));
1657 	fld.flowidn_proto = DNPROTO_NSP;
1658 
1659 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1660 	if (skb == NULL)
1661 		return -ENOBUFS;
1662 	skb_reset_mac_header(skb);
1663 	cb = DN_SKB_CB(skb);
1664 
1665 	if (tb[RTA_SRC])
1666 		fld.saddr = nla_get_le16(tb[RTA_SRC]);
1667 
1668 	if (tb[RTA_DST])
1669 		fld.daddr = nla_get_le16(tb[RTA_DST]);
1670 
1671 	if (tb[RTA_IIF])
1672 		fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
1673 
1674 	if (fld.flowidn_iif) {
1675 		struct net_device *dev;
1676 		dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
1677 		if (!dev || !dev->dn_ptr) {
1678 			kfree_skb(skb);
1679 			return -ENODEV;
1680 		}
1681 		skb->protocol = htons(ETH_P_DNA_RT);
1682 		skb->dev = dev;
1683 		cb->src = fld.saddr;
1684 		cb->dst = fld.daddr;
1685 		local_bh_disable();
1686 		err = dn_route_input(skb);
1687 		local_bh_enable();
1688 		memset(cb, 0, sizeof(struct dn_skb_cb));
1689 		rt = (struct dn_route *)skb_dst(skb);
1690 		if (!err && -rt->dst.error)
1691 			err = rt->dst.error;
1692 	} else {
1693 		if (tb[RTA_OIF])
1694 			fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
1695 
1696 		err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
1697 	}
1698 
1699 	skb->dev = NULL;
1700 	if (err)
1701 		goto out_free;
1702 	skb_dst_set(skb, &rt->dst);
1703 	if (rtm->rtm_flags & RTM_F_NOTIFY)
1704 		rt->rt_flags |= RTCF_NOTIFY;
1705 
1706 	err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1707 	if (err < 0) {
1708 		err = -EMSGSIZE;
1709 		goto out_free;
1710 	}
1711 
1712 	return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).portid);
1713 
1714 out_free:
1715 	kfree_skb(skb);
1716 	return err;
1717 }
1718 
1719 /*
1720  * For routers, this is called from dn_fib_dump, but for endnodes its
1721  * called directly from the rtnetlink dispatch table.
1722  */
dn_cache_dump(struct sk_buff * skb,struct netlink_callback * cb)1723 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1724 {
1725 	struct net *net = sock_net(skb->sk);
1726 	struct dn_route *rt;
1727 	int h, s_h;
1728 	int idx, s_idx;
1729 	struct rtmsg *rtm;
1730 
1731 	if (!net_eq(net, &init_net))
1732 		return 0;
1733 
1734 	if (nlmsg_len(cb->nlh) < sizeof(struct rtmsg))
1735 		return -EINVAL;
1736 
1737 	rtm = nlmsg_data(cb->nlh);
1738 	if (!(rtm->rtm_flags & RTM_F_CLONED))
1739 		return 0;
1740 
1741 	s_h = cb->args[0];
1742 	s_idx = idx = cb->args[1];
1743 	for(h = 0; h <= dn_rt_hash_mask; h++) {
1744 		if (h < s_h)
1745 			continue;
1746 		if (h > s_h)
1747 			s_idx = 0;
1748 		rcu_read_lock_bh();
1749 		for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1750 			rt;
1751 			rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {
1752 			if (idx < s_idx)
1753 				continue;
1754 			skb_dst_set(skb, dst_clone(&rt->dst));
1755 			if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).portid,
1756 					cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1757 					1, NLM_F_MULTI) < 0) {
1758 				skb_dst_drop(skb);
1759 				rcu_read_unlock_bh();
1760 				goto done;
1761 			}
1762 			skb_dst_drop(skb);
1763 		}
1764 		rcu_read_unlock_bh();
1765 	}
1766 
1767 done:
1768 	cb->args[0] = h;
1769 	cb->args[1] = idx;
1770 	return skb->len;
1771 }
1772 
1773 #ifdef CONFIG_PROC_FS
1774 struct dn_rt_cache_iter_state {
1775 	int bucket;
1776 };
1777 
dn_rt_cache_get_first(struct seq_file * seq)1778 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1779 {
1780 	struct dn_route *rt = NULL;
1781 	struct dn_rt_cache_iter_state *s = seq->private;
1782 
1783 	for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1784 		rcu_read_lock_bh();
1785 		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1786 		if (rt)
1787 			break;
1788 		rcu_read_unlock_bh();
1789 	}
1790 	return rt;
1791 }
1792 
dn_rt_cache_get_next(struct seq_file * seq,struct dn_route * rt)1793 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1794 {
1795 	struct dn_rt_cache_iter_state *s = seq->private;
1796 
1797 	rt = rcu_dereference_bh(rt->dst.dn_next);
1798 	while (!rt) {
1799 		rcu_read_unlock_bh();
1800 		if (--s->bucket < 0)
1801 			break;
1802 		rcu_read_lock_bh();
1803 		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1804 	}
1805 	return rt;
1806 }
1807 
dn_rt_cache_seq_start(struct seq_file * seq,loff_t * pos)1808 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1809 {
1810 	struct dn_route *rt = dn_rt_cache_get_first(seq);
1811 
1812 	if (rt) {
1813 		while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1814 			--*pos;
1815 	}
1816 	return *pos ? NULL : rt;
1817 }
1818 
dn_rt_cache_seq_next(struct seq_file * seq,void * v,loff_t * pos)1819 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1820 {
1821 	struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1822 	++*pos;
1823 	return rt;
1824 }
1825 
dn_rt_cache_seq_stop(struct seq_file * seq,void * v)1826 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1827 {
1828 	if (v)
1829 		rcu_read_unlock_bh();
1830 }
1831 
dn_rt_cache_seq_show(struct seq_file * seq,void * v)1832 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1833 {
1834 	struct dn_route *rt = v;
1835 	char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1836 
1837 	seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1838 		   rt->dst.dev ? rt->dst.dev->name : "*",
1839 		   dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1840 		   dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1841 		   atomic_read(&rt->dst.__refcnt),
1842 		   rt->dst.__use, 0);
1843 	return 0;
1844 }
1845 
1846 static const struct seq_operations dn_rt_cache_seq_ops = {
1847 	.start	= dn_rt_cache_seq_start,
1848 	.next	= dn_rt_cache_seq_next,
1849 	.stop	= dn_rt_cache_seq_stop,
1850 	.show	= dn_rt_cache_seq_show,
1851 };
1852 
dn_rt_cache_seq_open(struct inode * inode,struct file * file)1853 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1854 {
1855 	return seq_open_private(file, &dn_rt_cache_seq_ops,
1856 			sizeof(struct dn_rt_cache_iter_state));
1857 }
1858 
1859 static const struct file_operations dn_rt_cache_seq_fops = {
1860 	.owner	 = THIS_MODULE,
1861 	.open	 = dn_rt_cache_seq_open,
1862 	.read	 = seq_read,
1863 	.llseek	 = seq_lseek,
1864 	.release = seq_release_private,
1865 };
1866 
1867 #endif /* CONFIG_PROC_FS */
1868 
dn_route_init(void)1869 void __init dn_route_init(void)
1870 {
1871 	int i, goal, order;
1872 
1873 	dn_dst_ops.kmem_cachep =
1874 		kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1875 				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1876 	dst_entries_init(&dn_dst_ops);
1877 	setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1878 	dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1879 	add_timer(&dn_route_timer);
1880 
1881 	goal = totalram_pages >> (26 - PAGE_SHIFT);
1882 
1883 	for(order = 0; (1UL << order) < goal; order++)
1884 		/* NOTHING */;
1885 
1886 	/*
1887 	 * Only want 1024 entries max, since the table is very, very unlikely
1888 	 * to be larger than that.
1889 	 */
1890 	while(order && ((((1UL << order) * PAGE_SIZE) /
1891 				sizeof(struct dn_rt_hash_bucket)) >= 2048))
1892 		order--;
1893 
1894 	do {
1895 		dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1896 			sizeof(struct dn_rt_hash_bucket);
1897 		while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1898 			dn_rt_hash_mask--;
1899 		dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1900 			__get_free_pages(GFP_ATOMIC, order);
1901 	} while (dn_rt_hash_table == NULL && --order > 0);
1902 
1903 	if (!dn_rt_hash_table)
1904 		panic("Failed to allocate DECnet route cache hash table\n");
1905 
1906 	printk(KERN_INFO
1907 		"DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1908 		dn_rt_hash_mask,
1909 		(long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1910 
1911 	dn_rt_hash_mask--;
1912 	for(i = 0; i <= dn_rt_hash_mask; i++) {
1913 		spin_lock_init(&dn_rt_hash_table[i].lock);
1914 		dn_rt_hash_table[i].chain = NULL;
1915 	}
1916 
1917 	dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1918 
1919 	proc_create("decnet_cache", S_IRUGO, init_net.proc_net,
1920 		    &dn_rt_cache_seq_fops);
1921 
1922 #ifdef CONFIG_DECNET_ROUTER
1923 	rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1924 		      dn_fib_dump, NULL);
1925 #else
1926 	rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1927 		      dn_cache_dump, NULL);
1928 #endif
1929 }
1930 
dn_route_cleanup(void)1931 void __exit dn_route_cleanup(void)
1932 {
1933 	del_timer(&dn_route_timer);
1934 	dn_run_flush(0);
1935 
1936 	remove_proc_entry("decnet_cache", init_net.proc_net);
1937 	dst_entries_destroy(&dn_dst_ops);
1938 }
1939 
1940