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(struct timer_list *unused);
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);
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 
dn_dst_check_expire(struct timer_list * unused)186 static void dn_dst_check_expire(struct timer_list *unused)
187 {
188 	int i;
189 	struct dn_route *rt;
190 	struct dn_route __rcu **rtp;
191 	unsigned long now = jiffies;
192 	unsigned long expire = 120 * HZ;
193 
194 	for (i = 0; i <= dn_rt_hash_mask; i++) {
195 		rtp = &dn_rt_hash_table[i].chain;
196 
197 		spin_lock(&dn_rt_hash_table[i].lock);
198 		while ((rt = rcu_dereference_protected(*rtp,
199 						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
200 			if (atomic_read(&rt->dst.__refcnt) > 1 ||
201 			    (now - rt->dst.lastuse) < expire) {
202 				rtp = &rt->dn_next;
203 				continue;
204 			}
205 			*rtp = rt->dn_next;
206 			rt->dn_next = NULL;
207 			dst_dev_put(&rt->dst);
208 			dst_release(&rt->dst);
209 		}
210 		spin_unlock(&dn_rt_hash_table[i].lock);
211 
212 		if ((jiffies - now) > 0)
213 			break;
214 	}
215 
216 	mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
217 }
218 
dn_dst_gc(struct dst_ops * ops)219 static int dn_dst_gc(struct dst_ops *ops)
220 {
221 	struct dn_route *rt;
222 	struct dn_route __rcu **rtp;
223 	int i;
224 	unsigned long now = jiffies;
225 	unsigned long expire = 10 * HZ;
226 
227 	for (i = 0; i <= dn_rt_hash_mask; i++) {
228 
229 		spin_lock_bh(&dn_rt_hash_table[i].lock);
230 		rtp = &dn_rt_hash_table[i].chain;
231 
232 		while ((rt = rcu_dereference_protected(*rtp,
233 						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
234 			if (atomic_read(&rt->dst.__refcnt) > 1 ||
235 			    (now - rt->dst.lastuse) < expire) {
236 				rtp = &rt->dn_next;
237 				continue;
238 			}
239 			*rtp = rt->dn_next;
240 			rt->dn_next = NULL;
241 			dst_dev_put(&rt->dst);
242 			dst_release(&rt->dst);
243 			break;
244 		}
245 		spin_unlock_bh(&dn_rt_hash_table[i].lock);
246 	}
247 
248 	return 0;
249 }
250 
251 /*
252  * The decnet standards don't impose a particular minimum mtu, what they
253  * do insist on is that the routing layer accepts a datagram of at least
254  * 230 bytes long. Here we have to subtract the routing header length from
255  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
256  * assume the worst and use a long header size.
257  *
258  * We update both the mtu and the advertised mss (i.e. the segment size we
259  * advertise to the other end).
260  */
dn_dst_update_pmtu(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb,u32 mtu)261 static void dn_dst_update_pmtu(struct dst_entry *dst, struct sock *sk,
262 			       struct sk_buff *skb, u32 mtu)
263 {
264 	struct dn_route *rt = (struct dn_route *) dst;
265 	struct neighbour *n = rt->n;
266 	u32 min_mtu = 230;
267 	struct dn_dev *dn;
268 
269 	dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
270 
271 	if (dn && dn->use_long == 0)
272 		min_mtu -= 6;
273 	else
274 		min_mtu -= 21;
275 
276 	if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
277 		if (!(dst_metric_locked(dst, RTAX_MTU))) {
278 			dst_metric_set(dst, RTAX_MTU, mtu);
279 			dst_set_expires(dst, dn_rt_mtu_expires);
280 		}
281 		if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
282 			u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
283 			u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
284 			if (!existing_mss || existing_mss > mss)
285 				dst_metric_set(dst, RTAX_ADVMSS, mss);
286 		}
287 	}
288 }
289 
dn_dst_redirect(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb)290 static void dn_dst_redirect(struct dst_entry *dst, struct sock *sk,
291 			    struct sk_buff *skb)
292 {
293 }
294 
295 /*
296  * When a route has been marked obsolete. (e.g. routing cache flush)
297  */
dn_dst_check(struct dst_entry * dst,__u32 cookie)298 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
299 {
300 	return NULL;
301 }
302 
dn_dst_negative_advice(struct dst_entry * dst)303 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
304 {
305 	dst_release(dst);
306 	return NULL;
307 }
308 
dn_dst_link_failure(struct sk_buff * skb)309 static void dn_dst_link_failure(struct sk_buff *skb)
310 {
311 }
312 
compare_keys(struct flowidn * fl1,struct flowidn * fl2)313 static inline int compare_keys(struct flowidn *fl1, struct flowidn *fl2)
314 {
315 	return ((fl1->daddr ^ fl2->daddr) |
316 		(fl1->saddr ^ fl2->saddr) |
317 		(fl1->flowidn_mark ^ fl2->flowidn_mark) |
318 		(fl1->flowidn_scope ^ fl2->flowidn_scope) |
319 		(fl1->flowidn_oif ^ fl2->flowidn_oif) |
320 		(fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
321 }
322 
dn_insert_route(struct dn_route * rt,unsigned int hash,struct dn_route ** rp)323 static int dn_insert_route(struct dn_route *rt, unsigned int hash, struct dn_route **rp)
324 {
325 	struct dn_route *rth;
326 	struct dn_route __rcu **rthp;
327 	unsigned long now = jiffies;
328 
329 	rthp = &dn_rt_hash_table[hash].chain;
330 
331 	spin_lock_bh(&dn_rt_hash_table[hash].lock);
332 	while ((rth = rcu_dereference_protected(*rthp,
333 						lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
334 		if (compare_keys(&rth->fld, &rt->fld)) {
335 			/* Put it first */
336 			*rthp = rth->dn_next;
337 			rcu_assign_pointer(rth->dn_next,
338 					   dn_rt_hash_table[hash].chain);
339 			rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
340 
341 			dst_hold_and_use(&rth->dst, now);
342 			spin_unlock_bh(&dn_rt_hash_table[hash].lock);
343 
344 			dst_release_immediate(&rt->dst);
345 			*rp = rth;
346 			return 0;
347 		}
348 		rthp = &rth->dn_next;
349 	}
350 
351 	rcu_assign_pointer(rt->dn_next, dn_rt_hash_table[hash].chain);
352 	rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
353 
354 	dst_hold_and_use(&rt->dst, now);
355 	spin_unlock_bh(&dn_rt_hash_table[hash].lock);
356 	*rp = rt;
357 	return 0;
358 }
359 
dn_run_flush(struct timer_list * unused)360 static void dn_run_flush(struct timer_list *unused)
361 {
362 	int i;
363 	struct dn_route *rt, *next;
364 
365 	for (i = 0; i < dn_rt_hash_mask; i++) {
366 		spin_lock_bh(&dn_rt_hash_table[i].lock);
367 
368 		if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
369 			goto nothing_to_declare;
370 
371 		for(; rt; rt = next) {
372 			next = rcu_dereference_raw(rt->dn_next);
373 			RCU_INIT_POINTER(rt->dn_next, NULL);
374 			dst_dev_put(&rt->dst);
375 			dst_release(&rt->dst);
376 		}
377 
378 nothing_to_declare:
379 		spin_unlock_bh(&dn_rt_hash_table[i].lock);
380 	}
381 }
382 
383 static DEFINE_SPINLOCK(dn_rt_flush_lock);
384 
dn_rt_cache_flush(int delay)385 void dn_rt_cache_flush(int delay)
386 {
387 	unsigned long now = jiffies;
388 	int user_mode = !in_interrupt();
389 
390 	if (delay < 0)
391 		delay = dn_rt_min_delay;
392 
393 	spin_lock_bh(&dn_rt_flush_lock);
394 
395 	if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
396 		long tmo = (long)(dn_rt_deadline - now);
397 
398 		if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
399 			tmo = 0;
400 
401 		if (delay > tmo)
402 			delay = tmo;
403 	}
404 
405 	if (delay <= 0) {
406 		spin_unlock_bh(&dn_rt_flush_lock);
407 		dn_run_flush(NULL);
408 		return;
409 	}
410 
411 	if (dn_rt_deadline == 0)
412 		dn_rt_deadline = now + dn_rt_max_delay;
413 
414 	dn_rt_flush_timer.expires = now + delay;
415 	add_timer(&dn_rt_flush_timer);
416 	spin_unlock_bh(&dn_rt_flush_lock);
417 }
418 
419 /**
420  * dn_return_short - Return a short packet to its sender
421  * @skb: The packet to return
422  *
423  */
dn_return_short(struct sk_buff * skb)424 static int dn_return_short(struct sk_buff *skb)
425 {
426 	struct dn_skb_cb *cb;
427 	unsigned char *ptr;
428 	__le16 *src;
429 	__le16 *dst;
430 
431 	/* Add back headers */
432 	skb_push(skb, skb->data - skb_network_header(skb));
433 
434 	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
435 		return NET_RX_DROP;
436 
437 	cb = DN_SKB_CB(skb);
438 	/* Skip packet length and point to flags */
439 	ptr = skb->data + 2;
440 	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
441 
442 	dst = (__le16 *)ptr;
443 	ptr += 2;
444 	src = (__le16 *)ptr;
445 	ptr += 2;
446 	*ptr = 0; /* Zero hop count */
447 
448 	swap(*src, *dst);
449 
450 	skb->pkt_type = PACKET_OUTGOING;
451 	dn_rt_finish_output(skb, NULL, NULL);
452 	return NET_RX_SUCCESS;
453 }
454 
455 /**
456  * dn_return_long - Return a long packet to its sender
457  * @skb: The long format packet to return
458  *
459  */
dn_return_long(struct sk_buff * skb)460 static int dn_return_long(struct sk_buff *skb)
461 {
462 	struct dn_skb_cb *cb;
463 	unsigned char *ptr;
464 	unsigned char *src_addr, *dst_addr;
465 	unsigned char tmp[ETH_ALEN];
466 
467 	/* Add back all headers */
468 	skb_push(skb, skb->data - skb_network_header(skb));
469 
470 	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
471 		return NET_RX_DROP;
472 
473 	cb = DN_SKB_CB(skb);
474 	/* Ignore packet length and point to flags */
475 	ptr = skb->data + 2;
476 
477 	/* Skip padding */
478 	if (*ptr & DN_RT_F_PF) {
479 		char padlen = (*ptr & ~DN_RT_F_PF);
480 		ptr += padlen;
481 	}
482 
483 	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
484 	ptr += 2;
485 	dst_addr = ptr;
486 	ptr += 8;
487 	src_addr = ptr;
488 	ptr += 6;
489 	*ptr = 0; /* Zero hop count */
490 
491 	/* Swap source and destination */
492 	memcpy(tmp, src_addr, ETH_ALEN);
493 	memcpy(src_addr, dst_addr, ETH_ALEN);
494 	memcpy(dst_addr, tmp, ETH_ALEN);
495 
496 	skb->pkt_type = PACKET_OUTGOING;
497 	dn_rt_finish_output(skb, dst_addr, src_addr);
498 	return NET_RX_SUCCESS;
499 }
500 
501 /**
502  * dn_route_rx_packet - Try and find a route for an incoming packet
503  * @skb: The packet to find a route for
504  *
505  * Returns: result of input function if route is found, error code otherwise
506  */
dn_route_rx_packet(struct net * net,struct sock * sk,struct sk_buff * skb)507 static int dn_route_rx_packet(struct net *net, struct sock *sk, struct sk_buff *skb)
508 {
509 	struct dn_skb_cb *cb;
510 	int err;
511 
512 	if ((err = dn_route_input(skb)) == 0)
513 		return dst_input(skb);
514 
515 	cb = DN_SKB_CB(skb);
516 	if (decnet_debug_level & 4) {
517 		char *devname = skb->dev ? skb->dev->name : "???";
518 
519 		printk(KERN_DEBUG
520 			"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
521 			(int)cb->rt_flags, devname, skb->len,
522 			le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
523 			err, skb->pkt_type);
524 	}
525 
526 	if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
527 		switch (cb->rt_flags & DN_RT_PKT_MSK) {
528 		case DN_RT_PKT_SHORT:
529 			return dn_return_short(skb);
530 		case DN_RT_PKT_LONG:
531 			return dn_return_long(skb);
532 		}
533 	}
534 
535 	kfree_skb(skb);
536 	return NET_RX_DROP;
537 }
538 
dn_route_rx_long(struct sk_buff * skb)539 static int dn_route_rx_long(struct sk_buff *skb)
540 {
541 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
542 	unsigned char *ptr = skb->data;
543 
544 	if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
545 		goto drop_it;
546 
547 	skb_pull(skb, 20);
548 	skb_reset_transport_header(skb);
549 
550 	/* Destination info */
551 	ptr += 2;
552 	cb->dst = dn_eth2dn(ptr);
553 	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
554 		goto drop_it;
555 	ptr += 6;
556 
557 
558 	/* Source info */
559 	ptr += 2;
560 	cb->src = dn_eth2dn(ptr);
561 	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
562 		goto drop_it;
563 	ptr += 6;
564 	/* Other junk */
565 	ptr++;
566 	cb->hops = *ptr++; /* Visit Count */
567 
568 	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
569 		       &init_net, NULL, skb, skb->dev, NULL,
570 		       dn_route_rx_packet);
571 
572 drop_it:
573 	kfree_skb(skb);
574 	return NET_RX_DROP;
575 }
576 
577 
578 
dn_route_rx_short(struct sk_buff * skb)579 static int dn_route_rx_short(struct sk_buff *skb)
580 {
581 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
582 	unsigned char *ptr = skb->data;
583 
584 	if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
585 		goto drop_it;
586 
587 	skb_pull(skb, 5);
588 	skb_reset_transport_header(skb);
589 
590 	cb->dst = *(__le16 *)ptr;
591 	ptr += 2;
592 	cb->src = *(__le16 *)ptr;
593 	ptr += 2;
594 	cb->hops = *ptr & 0x3f;
595 
596 	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING,
597 		       &init_net, NULL, skb, skb->dev, NULL,
598 		       dn_route_rx_packet);
599 
600 drop_it:
601 	kfree_skb(skb);
602 	return NET_RX_DROP;
603 }
604 
dn_route_discard(struct net * net,struct sock * sk,struct sk_buff * skb)605 static int dn_route_discard(struct net *net, struct sock *sk, struct sk_buff *skb)
606 {
607 	/*
608 	 * I know we drop the packet here, but thats considered success in
609 	 * this case
610 	 */
611 	kfree_skb(skb);
612 	return NET_RX_SUCCESS;
613 }
614 
dn_route_ptp_hello(struct net * net,struct sock * sk,struct sk_buff * skb)615 static int dn_route_ptp_hello(struct net *net, struct sock *sk, struct sk_buff *skb)
616 {
617 	dn_dev_hello(skb);
618 	dn_neigh_pointopoint_hello(skb);
619 	return NET_RX_SUCCESS;
620 }
621 
dn_route_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)622 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
623 {
624 	struct dn_skb_cb *cb;
625 	unsigned char flags = 0;
626 	__u16 len = le16_to_cpu(*(__le16 *)skb->data);
627 	struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
628 	unsigned char padlen = 0;
629 
630 	if (!net_eq(dev_net(dev), &init_net))
631 		goto dump_it;
632 
633 	if (dn == NULL)
634 		goto dump_it;
635 
636 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
637 		goto out;
638 
639 	if (!pskb_may_pull(skb, 3))
640 		goto dump_it;
641 
642 	skb_pull(skb, 2);
643 
644 	if (len > skb->len)
645 		goto dump_it;
646 
647 	skb_trim(skb, len);
648 
649 	flags = *skb->data;
650 
651 	cb = DN_SKB_CB(skb);
652 	cb->stamp = jiffies;
653 	cb->iif = dev->ifindex;
654 
655 	/*
656 	 * If we have padding, remove it.
657 	 */
658 	if (flags & DN_RT_F_PF) {
659 		padlen = flags & ~DN_RT_F_PF;
660 		if (!pskb_may_pull(skb, padlen + 1))
661 			goto dump_it;
662 		skb_pull(skb, padlen);
663 		flags = *skb->data;
664 	}
665 
666 	skb_reset_network_header(skb);
667 
668 	/*
669 	 * Weed out future version DECnet
670 	 */
671 	if (flags & DN_RT_F_VER)
672 		goto dump_it;
673 
674 	cb->rt_flags = flags;
675 
676 	if (decnet_debug_level & 1)
677 		printk(KERN_DEBUG
678 			"dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
679 			(int)flags, (dev) ? dev->name : "???", len, skb->len,
680 			padlen);
681 
682 	if (flags & DN_RT_PKT_CNTL) {
683 		if (unlikely(skb_linearize(skb)))
684 			goto dump_it;
685 
686 		switch (flags & DN_RT_CNTL_MSK) {
687 		case DN_RT_PKT_INIT:
688 			dn_dev_init_pkt(skb);
689 			break;
690 		case DN_RT_PKT_VERI:
691 			dn_dev_veri_pkt(skb);
692 			break;
693 		}
694 
695 		if (dn->parms.state != DN_DEV_S_RU)
696 			goto dump_it;
697 
698 		switch (flags & DN_RT_CNTL_MSK) {
699 		case DN_RT_PKT_HELO:
700 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
701 				       &init_net, NULL, skb, skb->dev, NULL,
702 				       dn_route_ptp_hello);
703 
704 		case DN_RT_PKT_L1RT:
705 		case DN_RT_PKT_L2RT:
706 			return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
707 				       &init_net, NULL, skb, skb->dev, NULL,
708 				       dn_route_discard);
709 		case DN_RT_PKT_ERTH:
710 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
711 				       &init_net, NULL, skb, skb->dev, NULL,
712 				       dn_neigh_router_hello);
713 
714 		case DN_RT_PKT_EEDH:
715 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
716 				       &init_net, NULL, skb, skb->dev, NULL,
717 				       dn_neigh_endnode_hello);
718 		}
719 	} else {
720 		if (dn->parms.state != DN_DEV_S_RU)
721 			goto dump_it;
722 
723 		skb_pull(skb, 1); /* Pull flags */
724 
725 		switch (flags & DN_RT_PKT_MSK) {
726 		case DN_RT_PKT_LONG:
727 			return dn_route_rx_long(skb);
728 		case DN_RT_PKT_SHORT:
729 			return dn_route_rx_short(skb);
730 		}
731 	}
732 
733 dump_it:
734 	kfree_skb(skb);
735 out:
736 	return NET_RX_DROP;
737 }
738 
dn_output(struct net * net,struct sock * sk,struct sk_buff * skb)739 static int dn_output(struct net *net, struct sock *sk, struct sk_buff *skb)
740 {
741 	struct dst_entry *dst = skb_dst(skb);
742 	struct dn_route *rt = (struct dn_route *)dst;
743 	struct net_device *dev = dst->dev;
744 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
745 
746 	int err = -EINVAL;
747 
748 	if (rt->n == NULL)
749 		goto error;
750 
751 	skb->dev = dev;
752 
753 	cb->src = rt->rt_saddr;
754 	cb->dst = rt->rt_daddr;
755 
756 	/*
757 	 * Always set the Intra-Ethernet bit on all outgoing packets
758 	 * originated on this node. Only valid flag from upper layers
759 	 * is return-to-sender-requested. Set hop count to 0 too.
760 	 */
761 	cb->rt_flags &= ~DN_RT_F_RQR;
762 	cb->rt_flags |= DN_RT_F_IE;
763 	cb->hops = 0;
764 
765 	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT,
766 		       &init_net, sk, skb, NULL, dev,
767 		       dn_to_neigh_output);
768 
769 error:
770 	net_dbg_ratelimited("dn_output: This should not happen\n");
771 
772 	kfree_skb(skb);
773 
774 	return err;
775 }
776 
dn_forward(struct sk_buff * skb)777 static int dn_forward(struct sk_buff *skb)
778 {
779 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
780 	struct dst_entry *dst = skb_dst(skb);
781 	struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
782 	struct dn_route *rt;
783 	int header_len;
784 	struct net_device *dev = skb->dev;
785 
786 	if (skb->pkt_type != PACKET_HOST)
787 		goto drop;
788 
789 	/* Ensure that we have enough space for headers */
790 	rt = (struct dn_route *)skb_dst(skb);
791 	header_len = dn_db->use_long ? 21 : 6;
792 	if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
793 		goto drop;
794 
795 	/*
796 	 * Hop count exceeded.
797 	 */
798 	if (++cb->hops > 30)
799 		goto drop;
800 
801 	skb->dev = rt->dst.dev;
802 
803 	/*
804 	 * If packet goes out same interface it came in on, then set
805 	 * the Intra-Ethernet bit. This has no effect for short
806 	 * packets, so we don't need to test for them here.
807 	 */
808 	cb->rt_flags &= ~DN_RT_F_IE;
809 	if (rt->rt_flags & RTCF_DOREDIRECT)
810 		cb->rt_flags |= DN_RT_F_IE;
811 
812 	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD,
813 		       &init_net, NULL, skb, dev, skb->dev,
814 		       dn_to_neigh_output);
815 
816 drop:
817 	kfree_skb(skb);
818 	return NET_RX_DROP;
819 }
820 
821 /*
822  * Used to catch bugs. This should never normally get
823  * called.
824  */
dn_rt_bug_out(struct net * net,struct sock * sk,struct sk_buff * skb)825 static int dn_rt_bug_out(struct net *net, struct sock *sk, struct sk_buff *skb)
826 {
827 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
828 
829 	net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
830 			    le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
831 
832 	kfree_skb(skb);
833 
834 	return NET_RX_DROP;
835 }
836 
dn_rt_bug(struct sk_buff * skb)837 static int dn_rt_bug(struct sk_buff *skb)
838 {
839 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
840 
841 	net_dbg_ratelimited("dn_rt_bug: skb from:%04x to:%04x\n",
842 			    le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
843 
844 	kfree_skb(skb);
845 
846 	return NET_RX_DROP;
847 }
848 
dn_dst_default_advmss(const struct dst_entry * dst)849 static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
850 {
851 	return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
852 }
853 
dn_dst_mtu(const struct dst_entry * dst)854 static unsigned int dn_dst_mtu(const struct dst_entry *dst)
855 {
856 	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
857 
858 	return mtu ? : dst->dev->mtu;
859 }
860 
dn_dst_neigh_lookup(const struct dst_entry * dst,struct sk_buff * skb,const void * daddr)861 static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
862 					     struct sk_buff *skb,
863 					     const void *daddr)
864 {
865 	return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
866 }
867 
dn_rt_set_next_hop(struct dn_route * rt,struct dn_fib_res * res)868 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
869 {
870 	struct dn_fib_info *fi = res->fi;
871 	struct net_device *dev = rt->dst.dev;
872 	unsigned int mss_metric;
873 	struct neighbour *n;
874 
875 	if (fi) {
876 		if (DN_FIB_RES_GW(*res) &&
877 		    DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
878 			rt->rt_gateway = DN_FIB_RES_GW(*res);
879 		dst_init_metrics(&rt->dst, fi->fib_metrics, true);
880 	}
881 	rt->rt_type = res->type;
882 
883 	if (dev != NULL && rt->n == NULL) {
884 		n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
885 		if (IS_ERR(n))
886 			return PTR_ERR(n);
887 		rt->n = n;
888 	}
889 
890 	if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
891 		dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
892 	mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
893 	if (mss_metric) {
894 		unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
895 		if (mss_metric > mss)
896 			dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
897 	}
898 	return 0;
899 }
900 
dn_match_addr(__le16 addr1,__le16 addr2)901 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
902 {
903 	__u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
904 	int match = 16;
905 	while(tmp) {
906 		tmp >>= 1;
907 		match--;
908 	}
909 	return match;
910 }
911 
dnet_select_source(const struct net_device * dev,__le16 daddr,int scope)912 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
913 {
914 	__le16 saddr = 0;
915 	struct dn_dev *dn_db;
916 	struct dn_ifaddr *ifa;
917 	int best_match = 0;
918 	int ret;
919 
920 	rcu_read_lock();
921 	dn_db = rcu_dereference(dev->dn_ptr);
922 	for (ifa = rcu_dereference(dn_db->ifa_list);
923 	     ifa != NULL;
924 	     ifa = rcu_dereference(ifa->ifa_next)) {
925 		if (ifa->ifa_scope > scope)
926 			continue;
927 		if (!daddr) {
928 			saddr = ifa->ifa_local;
929 			break;
930 		}
931 		ret = dn_match_addr(daddr, ifa->ifa_local);
932 		if (ret > best_match)
933 			saddr = ifa->ifa_local;
934 		if (best_match == 0)
935 			saddr = ifa->ifa_local;
936 	}
937 	rcu_read_unlock();
938 
939 	return saddr;
940 }
941 
__dn_fib_res_prefsrc(struct dn_fib_res * res)942 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
943 {
944 	return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
945 }
946 
dn_fib_rules_map_destination(__le16 daddr,struct dn_fib_res * res)947 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
948 {
949 	__le16 mask = dnet_make_mask(res->prefixlen);
950 	return (daddr&~mask)|res->fi->fib_nh->nh_gw;
951 }
952 
dn_route_output_slow(struct dst_entry ** pprt,const struct flowidn * oldflp,int try_hard)953 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowidn *oldflp, int try_hard)
954 {
955 	struct flowidn fld = {
956 		.daddr = oldflp->daddr,
957 		.saddr = oldflp->saddr,
958 		.flowidn_scope = RT_SCOPE_UNIVERSE,
959 		.flowidn_mark = oldflp->flowidn_mark,
960 		.flowidn_iif = LOOPBACK_IFINDEX,
961 		.flowidn_oif = oldflp->flowidn_oif,
962 	};
963 	struct dn_route *rt = NULL;
964 	struct net_device *dev_out = NULL, *dev;
965 	struct neighbour *neigh = NULL;
966 	unsigned int hash;
967 	unsigned int flags = 0;
968 	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
969 	int err;
970 	int free_res = 0;
971 	__le16 gateway = 0;
972 
973 	if (decnet_debug_level & 16)
974 		printk(KERN_DEBUG
975 		       "dn_route_output_slow: dst=%04x src=%04x mark=%d"
976 		       " iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
977 		       le16_to_cpu(oldflp->saddr),
978 		       oldflp->flowidn_mark, LOOPBACK_IFINDEX,
979 		       oldflp->flowidn_oif);
980 
981 	/* If we have an output interface, verify its a DECnet device */
982 	if (oldflp->flowidn_oif) {
983 		dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
984 		err = -ENODEV;
985 		if (dev_out && dev_out->dn_ptr == NULL) {
986 			dev_put(dev_out);
987 			dev_out = NULL;
988 		}
989 		if (dev_out == NULL)
990 			goto out;
991 	}
992 
993 	/* If we have a source address, verify that its a local address */
994 	if (oldflp->saddr) {
995 		err = -EADDRNOTAVAIL;
996 
997 		if (dev_out) {
998 			if (dn_dev_islocal(dev_out, oldflp->saddr))
999 				goto source_ok;
1000 			dev_put(dev_out);
1001 			goto out;
1002 		}
1003 		rcu_read_lock();
1004 		for_each_netdev_rcu(&init_net, dev) {
1005 			if (!dev->dn_ptr)
1006 				continue;
1007 			if (!dn_dev_islocal(dev, oldflp->saddr))
1008 				continue;
1009 			if ((dev->flags & IFF_LOOPBACK) &&
1010 			    oldflp->daddr &&
1011 			    !dn_dev_islocal(dev, oldflp->daddr))
1012 				continue;
1013 
1014 			dev_out = dev;
1015 			break;
1016 		}
1017 		rcu_read_unlock();
1018 		if (dev_out == NULL)
1019 			goto out;
1020 		dev_hold(dev_out);
1021 source_ok:
1022 		;
1023 	}
1024 
1025 	/* No destination? Assume its local */
1026 	if (!fld.daddr) {
1027 		fld.daddr = fld.saddr;
1028 
1029 		if (dev_out)
1030 			dev_put(dev_out);
1031 		err = -EINVAL;
1032 		dev_out = init_net.loopback_dev;
1033 		if (!dev_out->dn_ptr)
1034 			goto out;
1035 		err = -EADDRNOTAVAIL;
1036 		dev_hold(dev_out);
1037 		if (!fld.daddr) {
1038 			fld.daddr =
1039 			fld.saddr = dnet_select_source(dev_out, 0,
1040 						       RT_SCOPE_HOST);
1041 			if (!fld.daddr)
1042 				goto out;
1043 		}
1044 		fld.flowidn_oif = LOOPBACK_IFINDEX;
1045 		res.type = RTN_LOCAL;
1046 		goto make_route;
1047 	}
1048 
1049 	if (decnet_debug_level & 16)
1050 		printk(KERN_DEBUG
1051 		       "dn_route_output_slow: initial checks complete."
1052 		       " dst=%04x src=%04x oif=%d try_hard=%d\n",
1053 		       le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1054 		       fld.flowidn_oif, try_hard);
1055 
1056 	/*
1057 	 * N.B. If the kernel is compiled without router support then
1058 	 * dn_fib_lookup() will evaluate to non-zero so this if () block
1059 	 * will always be executed.
1060 	 */
1061 	err = -ESRCH;
1062 	if (try_hard || (err = dn_fib_lookup(&fld, &res)) != 0) {
1063 		struct dn_dev *dn_db;
1064 		if (err != -ESRCH)
1065 			goto out;
1066 		/*
1067 		 * Here the fallback is basically the standard algorithm for
1068 		 * routing in endnodes which is described in the DECnet routing
1069 		 * docs
1070 		 *
1071 		 * If we are not trying hard, look in neighbour cache.
1072 		 * The result is tested to ensure that if a specific output
1073 		 * device/source address was requested, then we honour that
1074 		 * here
1075 		 */
1076 		if (!try_hard) {
1077 			neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1078 			if (neigh) {
1079 				if ((oldflp->flowidn_oif &&
1080 				    (neigh->dev->ifindex != oldflp->flowidn_oif)) ||
1081 				    (oldflp->saddr &&
1082 				    (!dn_dev_islocal(neigh->dev,
1083 						     oldflp->saddr)))) {
1084 					neigh_release(neigh);
1085 					neigh = NULL;
1086 				} else {
1087 					if (dev_out)
1088 						dev_put(dev_out);
1089 					if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1090 						dev_out = init_net.loopback_dev;
1091 						res.type = RTN_LOCAL;
1092 					} else {
1093 						dev_out = neigh->dev;
1094 					}
1095 					dev_hold(dev_out);
1096 					goto select_source;
1097 				}
1098 			}
1099 		}
1100 
1101 		/* Not there? Perhaps its a local address */
1102 		if (dev_out == NULL)
1103 			dev_out = dn_dev_get_default();
1104 		err = -ENODEV;
1105 		if (dev_out == NULL)
1106 			goto out;
1107 		dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1108 		if (!dn_db)
1109 			goto e_inval;
1110 		/* Possible improvement - check all devices for local addr */
1111 		if (dn_dev_islocal(dev_out, fld.daddr)) {
1112 			dev_put(dev_out);
1113 			dev_out = init_net.loopback_dev;
1114 			dev_hold(dev_out);
1115 			res.type = RTN_LOCAL;
1116 			goto select_source;
1117 		}
1118 		/* Not local either.... try sending it to the default router */
1119 		neigh = neigh_clone(dn_db->router);
1120 		BUG_ON(neigh && neigh->dev != dev_out);
1121 
1122 		/* Ok then, we assume its directly connected and move on */
1123 select_source:
1124 		if (neigh)
1125 			gateway = ((struct dn_neigh *)neigh)->addr;
1126 		if (gateway == 0)
1127 			gateway = fld.daddr;
1128 		if (fld.saddr == 0) {
1129 			fld.saddr = dnet_select_source(dev_out, gateway,
1130 						       res.type == RTN_LOCAL ?
1131 						       RT_SCOPE_HOST :
1132 						       RT_SCOPE_LINK);
1133 			if (fld.saddr == 0 && res.type != RTN_LOCAL)
1134 				goto e_addr;
1135 		}
1136 		fld.flowidn_oif = dev_out->ifindex;
1137 		goto make_route;
1138 	}
1139 	free_res = 1;
1140 
1141 	if (res.type == RTN_NAT)
1142 		goto e_inval;
1143 
1144 	if (res.type == RTN_LOCAL) {
1145 		if (!fld.saddr)
1146 			fld.saddr = fld.daddr;
1147 		if (dev_out)
1148 			dev_put(dev_out);
1149 		dev_out = init_net.loopback_dev;
1150 		dev_hold(dev_out);
1151 		if (!dev_out->dn_ptr)
1152 			goto e_inval;
1153 		fld.flowidn_oif = dev_out->ifindex;
1154 		if (res.fi)
1155 			dn_fib_info_put(res.fi);
1156 		res.fi = NULL;
1157 		goto make_route;
1158 	}
1159 
1160 	if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1161 		dn_fib_select_multipath(&fld, &res);
1162 
1163 	/*
1164 	 * We could add some logic to deal with default routes here and
1165 	 * get rid of some of the special casing above.
1166 	 */
1167 
1168 	if (!fld.saddr)
1169 		fld.saddr = DN_FIB_RES_PREFSRC(res);
1170 
1171 	if (dev_out)
1172 		dev_put(dev_out);
1173 	dev_out = DN_FIB_RES_DEV(res);
1174 	dev_hold(dev_out);
1175 	fld.flowidn_oif = dev_out->ifindex;
1176 	gateway = DN_FIB_RES_GW(res);
1177 
1178 make_route:
1179 	if (dev_out->flags & IFF_LOOPBACK)
1180 		flags |= RTCF_LOCAL;
1181 
1182 	rt = dst_alloc(&dn_dst_ops, dev_out, 0, DST_OBSOLETE_NONE, DST_HOST);
1183 	if (rt == NULL)
1184 		goto e_nobufs;
1185 
1186 	rt->dn_next = NULL;
1187 	memset(&rt->fld, 0, sizeof(rt->fld));
1188 	rt->fld.saddr        = oldflp->saddr;
1189 	rt->fld.daddr        = oldflp->daddr;
1190 	rt->fld.flowidn_oif  = oldflp->flowidn_oif;
1191 	rt->fld.flowidn_iif  = 0;
1192 	rt->fld.flowidn_mark = oldflp->flowidn_mark;
1193 
1194 	rt->rt_saddr      = fld.saddr;
1195 	rt->rt_daddr      = fld.daddr;
1196 	rt->rt_gateway    = gateway ? gateway : fld.daddr;
1197 	rt->rt_local_src  = fld.saddr;
1198 
1199 	rt->rt_dst_map    = fld.daddr;
1200 	rt->rt_src_map    = fld.saddr;
1201 
1202 	rt->n = neigh;
1203 	neigh = NULL;
1204 
1205 	rt->dst.lastuse = jiffies;
1206 	rt->dst.output  = dn_output;
1207 	rt->dst.input   = dn_rt_bug;
1208 	rt->rt_flags      = flags;
1209 	if (flags & RTCF_LOCAL)
1210 		rt->dst.input = dn_nsp_rx;
1211 
1212 	err = dn_rt_set_next_hop(rt, &res);
1213 	if (err)
1214 		goto e_neighbour;
1215 
1216 	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1217 	/* dn_insert_route() increments dst->__refcnt */
1218 	dn_insert_route(rt, hash, (struct dn_route **)pprt);
1219 
1220 done:
1221 	if (neigh)
1222 		neigh_release(neigh);
1223 	if (free_res)
1224 		dn_fib_res_put(&res);
1225 	if (dev_out)
1226 		dev_put(dev_out);
1227 out:
1228 	return err;
1229 
1230 e_addr:
1231 	err = -EADDRNOTAVAIL;
1232 	goto done;
1233 e_inval:
1234 	err = -EINVAL;
1235 	goto done;
1236 e_nobufs:
1237 	err = -ENOBUFS;
1238 	goto done;
1239 e_neighbour:
1240 	dst_release_immediate(&rt->dst);
1241 	goto e_nobufs;
1242 }
1243 
1244 
1245 /*
1246  * N.B. The flags may be moved into the flowi at some future stage.
1247  */
__dn_route_output_key(struct dst_entry ** pprt,const struct flowidn * flp,int flags)1248 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowidn *flp, int flags)
1249 {
1250 	unsigned int hash = dn_hash(flp->saddr, flp->daddr);
1251 	struct dn_route *rt = NULL;
1252 
1253 	if (!(flags & MSG_TRYHARD)) {
1254 		rcu_read_lock_bh();
1255 		for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1256 			rt = rcu_dereference_bh(rt->dn_next)) {
1257 			if ((flp->daddr == rt->fld.daddr) &&
1258 			    (flp->saddr == rt->fld.saddr) &&
1259 			    (flp->flowidn_mark == rt->fld.flowidn_mark) &&
1260 			    dn_is_output_route(rt) &&
1261 			    (rt->fld.flowidn_oif == flp->flowidn_oif)) {
1262 				dst_hold_and_use(&rt->dst, jiffies);
1263 				rcu_read_unlock_bh();
1264 				*pprt = &rt->dst;
1265 				return 0;
1266 			}
1267 		}
1268 		rcu_read_unlock_bh();
1269 	}
1270 
1271 	return dn_route_output_slow(pprt, flp, flags);
1272 }
1273 
dn_route_output_key(struct dst_entry ** pprt,struct flowidn * flp,int flags)1274 static int dn_route_output_key(struct dst_entry **pprt, struct flowidn *flp, int flags)
1275 {
1276 	int err;
1277 
1278 	err = __dn_route_output_key(pprt, flp, flags);
1279 	if (err == 0 && flp->flowidn_proto) {
1280 		*pprt = xfrm_lookup(&init_net, *pprt,
1281 				    flowidn_to_flowi(flp), NULL, 0);
1282 		if (IS_ERR(*pprt)) {
1283 			err = PTR_ERR(*pprt);
1284 			*pprt = NULL;
1285 		}
1286 	}
1287 	return err;
1288 }
1289 
dn_route_output_sock(struct dst_entry __rcu ** pprt,struct flowidn * fl,struct sock * sk,int flags)1290 int dn_route_output_sock(struct dst_entry __rcu **pprt, struct flowidn *fl, struct sock *sk, int flags)
1291 {
1292 	int err;
1293 
1294 	err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1295 	if (err == 0 && fl->flowidn_proto) {
1296 		*pprt = xfrm_lookup(&init_net, *pprt,
1297 				    flowidn_to_flowi(fl), sk, 0);
1298 		if (IS_ERR(*pprt)) {
1299 			err = PTR_ERR(*pprt);
1300 			*pprt = NULL;
1301 		}
1302 	}
1303 	return err;
1304 }
1305 
dn_route_input_slow(struct sk_buff * skb)1306 static int dn_route_input_slow(struct sk_buff *skb)
1307 {
1308 	struct dn_route *rt = NULL;
1309 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
1310 	struct net_device *in_dev = skb->dev;
1311 	struct net_device *out_dev = NULL;
1312 	struct dn_dev *dn_db;
1313 	struct neighbour *neigh = NULL;
1314 	unsigned int hash;
1315 	int flags = 0;
1316 	__le16 gateway = 0;
1317 	__le16 local_src = 0;
1318 	struct flowidn fld = {
1319 		.daddr = cb->dst,
1320 		.saddr = cb->src,
1321 		.flowidn_scope = RT_SCOPE_UNIVERSE,
1322 		.flowidn_mark = skb->mark,
1323 		.flowidn_iif = skb->dev->ifindex,
1324 	};
1325 	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1326 	int err = -EINVAL;
1327 	int free_res = 0;
1328 
1329 	dev_hold(in_dev);
1330 
1331 	if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1332 		goto out;
1333 
1334 	/* Zero source addresses are not allowed */
1335 	if (fld.saddr == 0)
1336 		goto out;
1337 
1338 	/*
1339 	 * In this case we've just received a packet from a source
1340 	 * outside ourselves pretending to come from us. We don't
1341 	 * allow it any further to prevent routing loops, spoofing and
1342 	 * other nasties. Loopback packets already have the dst attached
1343 	 * so this only affects packets which have originated elsewhere.
1344 	 */
1345 	err  = -ENOTUNIQ;
1346 	if (dn_dev_islocal(in_dev, cb->src))
1347 		goto out;
1348 
1349 	err = dn_fib_lookup(&fld, &res);
1350 	if (err) {
1351 		if (err != -ESRCH)
1352 			goto out;
1353 		/*
1354 		 * Is the destination us ?
1355 		 */
1356 		if (!dn_dev_islocal(in_dev, cb->dst))
1357 			goto e_inval;
1358 
1359 		res.type = RTN_LOCAL;
1360 	} else {
1361 		__le16 src_map = fld.saddr;
1362 		free_res = 1;
1363 
1364 		out_dev = DN_FIB_RES_DEV(res);
1365 		if (out_dev == NULL) {
1366 			net_crit_ratelimited("Bug in dn_route_input_slow() No output device\n");
1367 			goto e_inval;
1368 		}
1369 		dev_hold(out_dev);
1370 
1371 		if (res.r)
1372 			src_map = fld.saddr; /* no NAT support for now */
1373 
1374 		gateway = DN_FIB_RES_GW(res);
1375 		if (res.type == RTN_NAT) {
1376 			fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
1377 			dn_fib_res_put(&res);
1378 			free_res = 0;
1379 			if (dn_fib_lookup(&fld, &res))
1380 				goto e_inval;
1381 			free_res = 1;
1382 			if (res.type != RTN_UNICAST)
1383 				goto e_inval;
1384 			flags |= RTCF_DNAT;
1385 			gateway = fld.daddr;
1386 		}
1387 		fld.saddr = src_map;
1388 	}
1389 
1390 	switch(res.type) {
1391 	case RTN_UNICAST:
1392 		/*
1393 		 * Forwarding check here, we only check for forwarding
1394 		 * being turned off, if you want to only forward intra
1395 		 * area, its up to you to set the routing tables up
1396 		 * correctly.
1397 		 */
1398 		if (dn_db->parms.forwarding == 0)
1399 			goto e_inval;
1400 
1401 		if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1402 			dn_fib_select_multipath(&fld, &res);
1403 
1404 		/*
1405 		 * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1406 		 * flag as a hint to set the intra-ethernet bit when
1407 		 * forwarding. If we've got NAT in operation, we don't do
1408 		 * this optimisation.
1409 		 */
1410 		if (out_dev == in_dev && !(flags & RTCF_NAT))
1411 			flags |= RTCF_DOREDIRECT;
1412 
1413 		local_src = DN_FIB_RES_PREFSRC(res);
1414 
1415 	case RTN_BLACKHOLE:
1416 	case RTN_UNREACHABLE:
1417 		break;
1418 	case RTN_LOCAL:
1419 		flags |= RTCF_LOCAL;
1420 		fld.saddr = cb->dst;
1421 		fld.daddr = cb->src;
1422 
1423 		/* Routing tables gave us a gateway */
1424 		if (gateway)
1425 			goto make_route;
1426 
1427 		/* Packet was intra-ethernet, so we know its on-link */
1428 		if (cb->rt_flags & DN_RT_F_IE) {
1429 			gateway = cb->src;
1430 			goto make_route;
1431 		}
1432 
1433 		/* Use the default router if there is one */
1434 		neigh = neigh_clone(dn_db->router);
1435 		if (neigh) {
1436 			gateway = ((struct dn_neigh *)neigh)->addr;
1437 			goto make_route;
1438 		}
1439 
1440 		/* Close eyes and pray */
1441 		gateway = cb->src;
1442 		goto make_route;
1443 	default:
1444 		goto e_inval;
1445 	}
1446 
1447 make_route:
1448 	rt = dst_alloc(&dn_dst_ops, out_dev, 1, DST_OBSOLETE_NONE, DST_HOST);
1449 	if (rt == NULL)
1450 		goto e_nobufs;
1451 
1452 	rt->dn_next = NULL;
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_out;
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() increments dst->__refcnt */
1496 	dn_insert_route(rt, hash, &rt);
1497 	skb_dst_set(skb, &rt->dst);
1498 
1499 done:
1500 	if (neigh)
1501 		neigh_release(neigh);
1502 	if (free_res)
1503 		dn_fib_res_put(&res);
1504 	dev_put(in_dev);
1505 	if (out_dev)
1506 		dev_put(out_dev);
1507 out:
1508 	return err;
1509 
1510 e_inval:
1511 	err = -EINVAL;
1512 	goto done;
1513 
1514 e_nobufs:
1515 	err = -ENOBUFS;
1516 	goto done;
1517 
1518 e_neighbour:
1519 	dst_release_immediate(&rt->dst);
1520 	goto done;
1521 }
1522 
dn_route_input(struct sk_buff * skb)1523 static int dn_route_input(struct sk_buff *skb)
1524 {
1525 	struct dn_route *rt;
1526 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
1527 	unsigned int hash = dn_hash(cb->src, cb->dst);
1528 
1529 	if (skb_dst(skb))
1530 		return 0;
1531 
1532 	rcu_read_lock();
1533 	for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1534 	    rt = rcu_dereference(rt->dn_next)) {
1535 		if ((rt->fld.saddr == cb->src) &&
1536 		    (rt->fld.daddr == cb->dst) &&
1537 		    (rt->fld.flowidn_oif == 0) &&
1538 		    (rt->fld.flowidn_mark == skb->mark) &&
1539 		    (rt->fld.flowidn_iif == cb->iif)) {
1540 			dst_hold_and_use(&rt->dst, jiffies);
1541 			rcu_read_unlock();
1542 			skb_dst_set(skb, (struct dst_entry *)rt);
1543 			return 0;
1544 		}
1545 	}
1546 	rcu_read_unlock();
1547 
1548 	return dn_route_input_slow(skb);
1549 }
1550 
dn_rt_fill_info(struct sk_buff * skb,u32 portid,u32 seq,int event,int nowait,unsigned int flags)1551 static int dn_rt_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
1552 			   int event, int nowait, unsigned int flags)
1553 {
1554 	struct dn_route *rt = (struct dn_route *)skb_dst(skb);
1555 	struct rtmsg *r;
1556 	struct nlmsghdr *nlh;
1557 	long expires;
1558 
1559 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*r), flags);
1560 	if (!nlh)
1561 		return -EMSGSIZE;
1562 
1563 	r = nlmsg_data(nlh);
1564 	r->rtm_family = AF_DECnet;
1565 	r->rtm_dst_len = 16;
1566 	r->rtm_src_len = 0;
1567 	r->rtm_tos = 0;
1568 	r->rtm_table = RT_TABLE_MAIN;
1569 	r->rtm_type = rt->rt_type;
1570 	r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1571 	r->rtm_scope = RT_SCOPE_UNIVERSE;
1572 	r->rtm_protocol = RTPROT_UNSPEC;
1573 
1574 	if (rt->rt_flags & RTCF_NOTIFY)
1575 		r->rtm_flags |= RTM_F_NOTIFY;
1576 
1577 	if (nla_put_u32(skb, RTA_TABLE, RT_TABLE_MAIN) < 0 ||
1578 	    nla_put_le16(skb, RTA_DST, rt->rt_daddr) < 0)
1579 		goto errout;
1580 
1581 	if (rt->fld.saddr) {
1582 		r->rtm_src_len = 16;
1583 		if (nla_put_le16(skb, RTA_SRC, rt->fld.saddr) < 0)
1584 			goto errout;
1585 	}
1586 	if (rt->dst.dev &&
1587 	    nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex) < 0)
1588 		goto errout;
1589 
1590 	/*
1591 	 * Note to self - change this if input routes reverse direction when
1592 	 * they deal only with inputs and not with replies like they do
1593 	 * currently.
1594 	 */
1595 	if (nla_put_le16(skb, RTA_PREFSRC, rt->rt_local_src) < 0)
1596 		goto errout;
1597 
1598 	if (rt->rt_daddr != rt->rt_gateway &&
1599 	    nla_put_le16(skb, RTA_GATEWAY, rt->rt_gateway) < 0)
1600 		goto errout;
1601 
1602 	if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1603 		goto errout;
1604 
1605 	expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1606 	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, expires,
1607 			       rt->dst.error) < 0)
1608 		goto errout;
1609 
1610 	if (dn_is_input_route(rt) &&
1611 	    nla_put_u32(skb, RTA_IIF, rt->fld.flowidn_iif) < 0)
1612 		goto errout;
1613 
1614 	nlmsg_end(skb, nlh);
1615 	return 0;
1616 
1617 errout:
1618 	nlmsg_cancel(skb, nlh);
1619 	return -EMSGSIZE;
1620 }
1621 
1622 const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
1623 	[RTA_DST]		= { .type = NLA_U16 },
1624 	[RTA_SRC]		= { .type = NLA_U16 },
1625 	[RTA_IIF]		= { .type = NLA_U32 },
1626 	[RTA_OIF]		= { .type = NLA_U32 },
1627 	[RTA_GATEWAY]		= { .type = NLA_U16 },
1628 	[RTA_PRIORITY]		= { .type = NLA_U32 },
1629 	[RTA_PREFSRC]		= { .type = NLA_U16 },
1630 	[RTA_METRICS]		= { .type = NLA_NESTED },
1631 	[RTA_MULTIPATH]		= { .type = NLA_NESTED },
1632 	[RTA_TABLE]		= { .type = NLA_U32 },
1633 	[RTA_MARK]		= { .type = NLA_U32 },
1634 };
1635 
1636 /*
1637  * This is called by both endnodes and routers now.
1638  */
dn_cache_getroute(struct sk_buff * in_skb,struct nlmsghdr * nlh,struct netlink_ext_ack * extack)1639 static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
1640 			     struct netlink_ext_ack *extack)
1641 {
1642 	struct net *net = sock_net(in_skb->sk);
1643 	struct rtmsg *rtm = nlmsg_data(nlh);
1644 	struct dn_route *rt = NULL;
1645 	struct dn_skb_cb *cb;
1646 	int err;
1647 	struct sk_buff *skb;
1648 	struct flowidn fld;
1649 	struct nlattr *tb[RTA_MAX+1];
1650 
1651 	if (!net_eq(net, &init_net))
1652 		return -EINVAL;
1653 
1654 	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_dn_policy,
1655 			  extack);
1656 	if (err < 0)
1657 		return err;
1658 
1659 	memset(&fld, 0, sizeof(fld));
1660 	fld.flowidn_proto = DNPROTO_NSP;
1661 
1662 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1663 	if (skb == NULL)
1664 		return -ENOBUFS;
1665 	skb_reset_mac_header(skb);
1666 	cb = DN_SKB_CB(skb);
1667 
1668 	if (tb[RTA_SRC])
1669 		fld.saddr = nla_get_le16(tb[RTA_SRC]);
1670 
1671 	if (tb[RTA_DST])
1672 		fld.daddr = nla_get_le16(tb[RTA_DST]);
1673 
1674 	if (tb[RTA_IIF])
1675 		fld.flowidn_iif = nla_get_u32(tb[RTA_IIF]);
1676 
1677 	if (fld.flowidn_iif) {
1678 		struct net_device *dev;
1679 		dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
1680 		if (!dev || !dev->dn_ptr) {
1681 			kfree_skb(skb);
1682 			return -ENODEV;
1683 		}
1684 		skb->protocol = htons(ETH_P_DNA_RT);
1685 		skb->dev = dev;
1686 		cb->src = fld.saddr;
1687 		cb->dst = fld.daddr;
1688 		local_bh_disable();
1689 		err = dn_route_input(skb);
1690 		local_bh_enable();
1691 		memset(cb, 0, sizeof(struct dn_skb_cb));
1692 		rt = (struct dn_route *)skb_dst(skb);
1693 		if (!err && -rt->dst.error)
1694 			err = rt->dst.error;
1695 	} else {
1696 		if (tb[RTA_OIF])
1697 			fld.flowidn_oif = nla_get_u32(tb[RTA_OIF]);
1698 
1699 		err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
1700 	}
1701 
1702 	skb->dev = NULL;
1703 	if (err)
1704 		goto out_free;
1705 	skb_dst_set(skb, &rt->dst);
1706 	if (rtm->rtm_flags & RTM_F_NOTIFY)
1707 		rt->rt_flags |= RTCF_NOTIFY;
1708 
1709 	err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1710 	if (err < 0) {
1711 		err = -EMSGSIZE;
1712 		goto out_free;
1713 	}
1714 
1715 	return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).portid);
1716 
1717 out_free:
1718 	kfree_skb(skb);
1719 	return err;
1720 }
1721 
1722 /*
1723  * For routers, this is called from dn_fib_dump, but for endnodes its
1724  * called directly from the rtnetlink dispatch table.
1725  */
dn_cache_dump(struct sk_buff * skb,struct netlink_callback * cb)1726 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1727 {
1728 	struct net *net = sock_net(skb->sk);
1729 	struct dn_route *rt;
1730 	int h, s_h;
1731 	int idx, s_idx;
1732 	struct rtmsg *rtm;
1733 
1734 	if (!net_eq(net, &init_net))
1735 		return 0;
1736 
1737 	if (nlmsg_len(cb->nlh) < sizeof(struct rtmsg))
1738 		return -EINVAL;
1739 
1740 	rtm = nlmsg_data(cb->nlh);
1741 	if (!(rtm->rtm_flags & RTM_F_CLONED))
1742 		return 0;
1743 
1744 	s_h = cb->args[0];
1745 	s_idx = idx = cb->args[1];
1746 	for(h = 0; h <= dn_rt_hash_mask; h++) {
1747 		if (h < s_h)
1748 			continue;
1749 		if (h > s_h)
1750 			s_idx = 0;
1751 		rcu_read_lock_bh();
1752 		for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1753 			rt;
1754 			rt = rcu_dereference_bh(rt->dn_next), idx++) {
1755 			if (idx < s_idx)
1756 				continue;
1757 			skb_dst_set(skb, dst_clone(&rt->dst));
1758 			if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).portid,
1759 					cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1760 					1, NLM_F_MULTI) < 0) {
1761 				skb_dst_drop(skb);
1762 				rcu_read_unlock_bh();
1763 				goto done;
1764 			}
1765 			skb_dst_drop(skb);
1766 		}
1767 		rcu_read_unlock_bh();
1768 	}
1769 
1770 done:
1771 	cb->args[0] = h;
1772 	cb->args[1] = idx;
1773 	return skb->len;
1774 }
1775 
1776 #ifdef CONFIG_PROC_FS
1777 struct dn_rt_cache_iter_state {
1778 	int bucket;
1779 };
1780 
dn_rt_cache_get_first(struct seq_file * seq)1781 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1782 {
1783 	struct dn_route *rt = NULL;
1784 	struct dn_rt_cache_iter_state *s = seq->private;
1785 
1786 	for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1787 		rcu_read_lock_bh();
1788 		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1789 		if (rt)
1790 			break;
1791 		rcu_read_unlock_bh();
1792 	}
1793 	return rt;
1794 }
1795 
dn_rt_cache_get_next(struct seq_file * seq,struct dn_route * rt)1796 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1797 {
1798 	struct dn_rt_cache_iter_state *s = seq->private;
1799 
1800 	rt = rcu_dereference_bh(rt->dn_next);
1801 	while (!rt) {
1802 		rcu_read_unlock_bh();
1803 		if (--s->bucket < 0)
1804 			break;
1805 		rcu_read_lock_bh();
1806 		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1807 	}
1808 	return rt;
1809 }
1810 
dn_rt_cache_seq_start(struct seq_file * seq,loff_t * pos)1811 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1812 {
1813 	struct dn_route *rt = dn_rt_cache_get_first(seq);
1814 
1815 	if (rt) {
1816 		while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1817 			--*pos;
1818 	}
1819 	return *pos ? NULL : rt;
1820 }
1821 
dn_rt_cache_seq_next(struct seq_file * seq,void * v,loff_t * pos)1822 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1823 {
1824 	struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1825 	++*pos;
1826 	return rt;
1827 }
1828 
dn_rt_cache_seq_stop(struct seq_file * seq,void * v)1829 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1830 {
1831 	if (v)
1832 		rcu_read_unlock_bh();
1833 }
1834 
dn_rt_cache_seq_show(struct seq_file * seq,void * v)1835 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1836 {
1837 	struct dn_route *rt = v;
1838 	char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1839 
1840 	seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1841 		   rt->dst.dev ? rt->dst.dev->name : "*",
1842 		   dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1843 		   dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1844 		   atomic_read(&rt->dst.__refcnt),
1845 		   rt->dst.__use, 0);
1846 	return 0;
1847 }
1848 
1849 static const struct seq_operations dn_rt_cache_seq_ops = {
1850 	.start	= dn_rt_cache_seq_start,
1851 	.next	= dn_rt_cache_seq_next,
1852 	.stop	= dn_rt_cache_seq_stop,
1853 	.show	= dn_rt_cache_seq_show,
1854 };
1855 #endif /* CONFIG_PROC_FS */
1856 
dn_route_init(void)1857 void __init dn_route_init(void)
1858 {
1859 	int i, goal, order;
1860 
1861 	dn_dst_ops.kmem_cachep =
1862 		kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1863 				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1864 	dst_entries_init(&dn_dst_ops);
1865 	timer_setup(&dn_route_timer, dn_dst_check_expire, 0);
1866 	dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1867 	add_timer(&dn_route_timer);
1868 
1869 	goal = totalram_pages >> (26 - PAGE_SHIFT);
1870 
1871 	for(order = 0; (1UL << order) < goal; order++)
1872 		/* NOTHING */;
1873 
1874 	/*
1875 	 * Only want 1024 entries max, since the table is very, very unlikely
1876 	 * to be larger than that.
1877 	 */
1878 	while(order && ((((1UL << order) * PAGE_SIZE) /
1879 				sizeof(struct dn_rt_hash_bucket)) >= 2048))
1880 		order--;
1881 
1882 	do {
1883 		dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1884 			sizeof(struct dn_rt_hash_bucket);
1885 		while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1886 			dn_rt_hash_mask--;
1887 		dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1888 			__get_free_pages(GFP_ATOMIC, order);
1889 	} while (dn_rt_hash_table == NULL && --order > 0);
1890 
1891 	if (!dn_rt_hash_table)
1892 		panic("Failed to allocate DECnet route cache hash table\n");
1893 
1894 	printk(KERN_INFO
1895 		"DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1896 		dn_rt_hash_mask,
1897 		(long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1898 
1899 	dn_rt_hash_mask--;
1900 	for(i = 0; i <= dn_rt_hash_mask; i++) {
1901 		spin_lock_init(&dn_rt_hash_table[i].lock);
1902 		dn_rt_hash_table[i].chain = NULL;
1903 	}
1904 
1905 	dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1906 
1907 	proc_create_seq_private("decnet_cache", 0444, init_net.proc_net,
1908 			&dn_rt_cache_seq_ops,
1909 			sizeof(struct dn_rt_cache_iter_state), NULL);
1910 
1911 #ifdef CONFIG_DECNET_ROUTER
1912 	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
1913 			     dn_cache_getroute, dn_fib_dump, 0);
1914 #else
1915 	rtnl_register_module(THIS_MODULE, PF_DECnet, RTM_GETROUTE,
1916 			     dn_cache_getroute, dn_cache_dump, 0);
1917 #endif
1918 }
1919 
dn_route_cleanup(void)1920 void __exit dn_route_cleanup(void)
1921 {
1922 	del_timer(&dn_route_timer);
1923 	dn_run_flush(NULL);
1924 
1925 	remove_proc_entry("decnet_cache", init_net.proc_net);
1926 	dst_entries_destroy(&dn_dst_ops);
1927 }
1928