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Root/net/decnet/dn_route.c

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 struct dst_entry dn_dst_negative_advice(struct dst_entry );
118	static void dn_dst_link_failure(struct sk_buff *);
119	static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
120	static struct neighbour dn_dst_neigh_lookup(const struct dst_entry dst, const void *daddr);
121	static int dn_route_input(struct sk_buff *);
122	static void dn_run_flush(unsigned long dummy);
123
124	static struct dn_rt_hash_bucket *dn_rt_hash_table;
125	static unsigned dn_rt_hash_mask;
126
127	static struct timer_list dn_route_timer;
128	static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
129	int decnet_dst_gc_interval = 2;
130
131	static struct dst_ops dn_dst_ops = {
132	.family = PF_DECnet,
133	.protocol = cpu_to_be16(ETH_P_DNA_RT),
134	.gc_thresh = 128,
135	.gc = dn_dst_gc,
136	.check = dn_dst_check,
137	.default_advmss = dn_dst_default_advmss,
138	.mtu = dn_dst_mtu,
139	.cow_metrics = dst_cow_metrics_generic,
140	.destroy = dn_dst_destroy,
141	.negative_advice = dn_dst_negative_advice,
142	.link_failure = dn_dst_link_failure,
143	.update_pmtu = dn_dst_update_pmtu,
144	.neigh_lookup = dn_dst_neigh_lookup,
145	};
146
147	static void dn_dst_destroy(struct dst_entry *dst)
148	{
149	dst_destroy_metrics_generic(dst);
150	}
151
152	static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
153	{
154	__u16 tmp = (__u16 __force)(src ^ dst);
155	tmp ^= (tmp >> 3);
156	tmp ^= (tmp >> 5);
157	tmp ^= (tmp >> 10);
158	return dn_rt_hash_mask & (unsigned)tmp;
159	}
160
161	static inline void dnrt_free(struct dn_route *rt)
162	{
163	call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
164	}
165
166	static inline void dnrt_drop(struct dn_route *rt)
167	{
168	dst_release(&rt->dst);
169	call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
170	}
171
172	static void dn_dst_check_expire(unsigned long dummy)
173	{
174	int i;
175	struct dn_route *rt;
176	struct dn_route __rcu **rtp;
177	unsigned long now = jiffies;
178	unsigned long expire = 120 * HZ;
179
180	for (i = 0; i <= dn_rt_hash_mask; i++) {
181	rtp = &dn_rt_hash_table[i].chain;
182
183	spin_lock(&dn_rt_hash_table[i].lock);
184	while ((rt = rcu_dereference_protected(*rtp,
185	lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
186	if (atomic_read(&rt->dst.__refcnt) \|\|
187	(now - rt->dst.lastuse) < expire) {
188	rtp = &rt->dst.dn_next;
189	continue;
190	}
191	*rtp = rt->dst.dn_next;
192	rt->dst.dn_next = NULL;
193	dnrt_free(rt);
194	}
195	spin_unlock(&dn_rt_hash_table[i].lock);
196
197	if ((jiffies - now) > 0)
198	break;
199	}
200
201	mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
202	}
203
204	static int dn_dst_gc(struct dst_ops *ops)
205	{
206	struct dn_route *rt;
207	struct dn_route __rcu **rtp;
208	int i;
209	unsigned long now = jiffies;
210	unsigned long expire = 10 * HZ;
211
212	for (i = 0; i <= dn_rt_hash_mask; i++) {
213
214	spin_lock_bh(&dn_rt_hash_table[i].lock);
215	rtp = &dn_rt_hash_table[i].chain;
216
217	while ((rt = rcu_dereference_protected(*rtp,
218	lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {
219	if (atomic_read(&rt->dst.__refcnt) \|\|
220	(now - rt->dst.lastuse) < expire) {
221	rtp = &rt->dst.dn_next;
222	continue;
223	}
224	*rtp = rt->dst.dn_next;
225	rt->dst.dn_next = NULL;
226	dnrt_drop(rt);
227	break;
228	}
229	spin_unlock_bh(&dn_rt_hash_table[i].lock);
230	}
231
232	return 0;
233	}
234
235	/*
236	* The decnet standards don't impose a particular minimum mtu, what they
237	* do insist on is that the routing layer accepts a datagram of at least
238	* 230 bytes long. Here we have to subtract the routing header length from
239	* 230 to get the minimum acceptable mtu. If there is no neighbour, then we
240	* assume the worst and use a long header size.
241	*
242	* We update both the mtu and the advertised mss (i.e. the segment size we
243	* advertise to the other end).
244	*/
245	static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
246	{
247	struct neighbour *n = dst_get_neighbour_noref(dst);
248	u32 min_mtu = 230;
249	struct dn_dev *dn;
250
251	dn = n ? rcu_dereference_raw(n->dev->dn_ptr) : NULL;
252
253	if (dn && dn->use_long == 0)
254	min_mtu -= 6;
255	else
256	min_mtu -= 21;
257
258	if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {
259	if (!(dst_metric_locked(dst, RTAX_MTU))) {
260	dst_metric_set(dst, RTAX_MTU, mtu);
261	dst_set_expires(dst, dn_rt_mtu_expires);
262	}
263	if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
264	u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
265	u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
266	if (!existing_mss \|\| existing_mss > mss)
267	dst_metric_set(dst, RTAX_ADVMSS, mss);
268	}
269	}
270	}
271
272	/*
273	* When a route has been marked obsolete. (e.g. routing cache flush)
274	*/
275	static struct dst_entry dn_dst_check(struct dst_entry dst, __u32 cookie)
276	{
277	return NULL;
278	}
279
280	static struct dst_entry dn_dst_negative_advice(struct dst_entry dst)
281	{
282	dst_release(dst);
283	return NULL;
284	}
285
286	static void dn_dst_link_failure(struct sk_buff *skb)
287	{
288	}
289
290	static inline int compare_keys(struct flowidn fl1, struct flowidn fl2)
291	{
292	return ((fl1->daddr ^ fl2->daddr) \|
293	(fl1->saddr ^ fl2->saddr) \|
294	(fl1->flowidn_mark ^ fl2->flowidn_mark) \|
295	(fl1->flowidn_scope ^ fl2->flowidn_scope) \|
296	(fl1->flowidn_oif ^ fl2->flowidn_oif) \|
297	(fl1->flowidn_iif ^ fl2->flowidn_iif)) == 0;
298	}
299
300	static int dn_insert_route(struct dn_route rt, unsigned hash, struct dn_route *rp)
301	{
302	struct dn_route *rth;
303	struct dn_route __rcu **rthp;
304	unsigned long now = jiffies;
305
306	rthp = &dn_rt_hash_table[hash].chain;
307
308	spin_lock_bh(&dn_rt_hash_table[hash].lock);
309	while ((rth = rcu_dereference_protected(*rthp,
310	lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {
311	if (compare_keys(&rth->fld, &rt->fld)) {
312	/* Put it first */
313	*rthp = rth->dst.dn_next;
314	rcu_assign_pointer(rth->dst.dn_next,
315	dn_rt_hash_table[hash].chain);
316	rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
317
318	dst_use(&rth->dst, now);
319	spin_unlock_bh(&dn_rt_hash_table[hash].lock);
320
321	dnrt_drop(rt);
322	*rp = rth;
323	return 0;
324	}
325	rthp = &rth->dst.dn_next;
326	}
327
328	rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);
329	rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
330
331	dst_use(&rt->dst, now);
332	spin_unlock_bh(&dn_rt_hash_table[hash].lock);
333	*rp = rt;
334	return 0;
335	}
336
337	static void dn_run_flush(unsigned long dummy)
338	{
339	int i;
340	struct dn_route rt, next;
341
342	for (i = 0; i < dn_rt_hash_mask; i++) {
343	spin_lock_bh(&dn_rt_hash_table[i].lock);
344
345	if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)
346	goto nothing_to_declare;
347
348	for(; rt; rt = next) {
349	next = rcu_dereference_raw(rt->dst.dn_next);
350	RCU_INIT_POINTER(rt->dst.dn_next, NULL);
351	dst_free((struct dst_entry *)rt);
352	}
353
354	nothing_to_declare:
355	spin_unlock_bh(&dn_rt_hash_table[i].lock);
356	}
357	}
358
359	static DEFINE_SPINLOCK(dn_rt_flush_lock);
360
361	void dn_rt_cache_flush(int delay)
362	{
363	unsigned long now = jiffies;
364	int user_mode = !in_interrupt();
365
366	if (delay < 0)
367	delay = dn_rt_min_delay;
368
369	spin_lock_bh(&dn_rt_flush_lock);
370
371	if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
372	long tmo = (long)(dn_rt_deadline - now);
373
374	if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
375	tmo = 0;
376
377	if (delay > tmo)
378	delay = tmo;
379	}
380
381	if (delay <= 0) {
382	spin_unlock_bh(&dn_rt_flush_lock);
383	dn_run_flush(0);
384	return;
385	}
386
387	if (dn_rt_deadline == 0)
388	dn_rt_deadline = now + dn_rt_max_delay;
389
390	dn_rt_flush_timer.expires = now + delay;
391	add_timer(&dn_rt_flush_timer);
392	spin_unlock_bh(&dn_rt_flush_lock);
393	}
394
395	/**
396	* dn_return_short - Return a short packet to its sender
397	* @skb: The packet to return
398	*
399	*/
400	static int dn_return_short(struct sk_buff *skb)
401	{
402	struct dn_skb_cb *cb;
403	unsigned char *ptr;
404	__le16 *src;
405	__le16 *dst;
406
407	/* Add back headers */
408	skb_push(skb, skb->data - skb_network_header(skb));
409
410	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
411	return NET_RX_DROP;
412
413	cb = DN_SKB_CB(skb);
414	/* Skip packet length and point to flags */
415	ptr = skb->data + 2;
416	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) \| DN_RT_F_RTS;
417
418	dst = (__le16 *)ptr;
419	ptr += 2;
420	src = (__le16 *)ptr;
421	ptr += 2;
422	ptr = 0; / Zero hop count */
423
424	swap(src, dst);
425
426	skb->pkt_type = PACKET_OUTGOING;
427	dn_rt_finish_output(skb, NULL, NULL);
428	return NET_RX_SUCCESS;
429	}
430
431	/**
432	* dn_return_long - Return a long packet to its sender
433	* @skb: The long format packet to return
434	*
435	*/
436	static int dn_return_long(struct sk_buff *skb)
437	{
438	struct dn_skb_cb *cb;
439	unsigned char *ptr;
440	unsigned char src_addr, dst_addr;
441	unsigned char tmp[ETH_ALEN];
442
443	/* Add back all headers */
444	skb_push(skb, skb->data - skb_network_header(skb));
445
446	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
447	return NET_RX_DROP;
448
449	cb = DN_SKB_CB(skb);
450	/* Ignore packet length and point to flags */
451	ptr = skb->data + 2;
452
453	/* Skip padding */
454	if (*ptr & DN_RT_F_PF) {
455	char padlen = (*ptr & ~DN_RT_F_PF);
456	ptr += padlen;
457	}
458
459	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) \| DN_RT_F_RTS;
460	ptr += 2;
461	dst_addr = ptr;
462	ptr += 8;
463	src_addr = ptr;
464	ptr += 6;
465	ptr = 0; / Zero hop count */
466
467	/* Swap source and destination */
468	memcpy(tmp, src_addr, ETH_ALEN);
469	memcpy(src_addr, dst_addr, ETH_ALEN);
470	memcpy(dst_addr, tmp, ETH_ALEN);
471
472	skb->pkt_type = PACKET_OUTGOING;
473	dn_rt_finish_output(skb, dst_addr, src_addr);
474	return NET_RX_SUCCESS;
475	}
476
477	/**
478	* dn_route_rx_packet - Try and find a route for an incoming packet
479	* @skb: The packet to find a route for
480	*
481	* Returns: result of input function if route is found, error code otherwise
482	*/
483	static int dn_route_rx_packet(struct sk_buff *skb)
484	{
485	struct dn_skb_cb *cb;
486	int err;
487
488	if ((err = dn_route_input(skb)) == 0)
489	return dst_input(skb);
490
491	cb = DN_SKB_CB(skb);
492	if (decnet_debug_level & 4) {
493	char *devname = skb->dev ? skb->dev->name : "???";
494
495	printk(KERN_DEBUG
496	"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
497	(int)cb->rt_flags, devname, skb->len,
498	le16_to_cpu(cb->src), le16_to_cpu(cb->dst),
499	err, skb->pkt_type);
500	}
501
502	if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
503	switch (cb->rt_flags & DN_RT_PKT_MSK) {
504	case DN_RT_PKT_SHORT:
505	return dn_return_short(skb);
506	case DN_RT_PKT_LONG:
507	return dn_return_long(skb);
508	}
509	}
510
511	kfree_skb(skb);
512	return NET_RX_DROP;
513	}
514
515	static int dn_route_rx_long(struct sk_buff *skb)
516	{
517	struct dn_skb_cb *cb = DN_SKB_CB(skb);
518	unsigned char *ptr = skb->data;
519
520	if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
521	goto drop_it;
522
523	skb_pull(skb, 20);
524	skb_reset_transport_header(skb);
525
526	/* Destination info */
527	ptr += 2;
528	cb->dst = dn_eth2dn(ptr);
529	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
530	goto drop_it;
531	ptr += 6;
532
533
534	/* Source info */
535	ptr += 2;
536	cb->src = dn_eth2dn(ptr);
537	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
538	goto drop_it;
539	ptr += 6;
540	/* Other junk */
541	ptr++;
542	cb->hops = ptr++; / Visit Count */
543
544	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
545	dn_route_rx_packet);
546
547	drop_it:
548	kfree_skb(skb);
549	return NET_RX_DROP;
550	}
551
552
553
554	static int dn_route_rx_short(struct sk_buff *skb)
555	{
556	struct dn_skb_cb *cb = DN_SKB_CB(skb);
557	unsigned char *ptr = skb->data;
558
559	if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
560	goto drop_it;
561
562	skb_pull(skb, 5);
563	skb_reset_transport_header(skb);
564
565	cb->dst = (__le16 )ptr;
566	ptr += 2;
567	cb->src = (__le16 )ptr;
568	ptr += 2;
569	cb->hops = *ptr & 0x3f;
570
571	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
572	dn_route_rx_packet);
573
574	drop_it:
575	kfree_skb(skb);
576	return NET_RX_DROP;
577	}
578
579	static int dn_route_discard(struct sk_buff *skb)
580	{
581	/*
582	* I know we drop the packet here, but thats considered success in
583	* this case
584	*/
585	kfree_skb(skb);
586	return NET_RX_SUCCESS;
587	}
588
589	static int dn_route_ptp_hello(struct sk_buff *skb)
590	{
591	dn_dev_hello(skb);
592	dn_neigh_pointopoint_hello(skb);
593	return NET_RX_SUCCESS;
594	}
595
596	int dn_route_rcv(struct sk_buff skb, struct net_device dev, struct packet_type pt, struct net_device orig_dev)
597	{
598	struct dn_skb_cb *cb;
599	unsigned char flags = 0;
600	__u16 len = le16_to_cpu((__le16 )skb->data);
601	struct dn_dev *dn = rcu_dereference(dev->dn_ptr);
602	unsigned char padlen = 0;
603
604	if (!net_eq(dev_net(dev), &init_net))
605	goto dump_it;
606
607	if (dn == NULL)
608	goto dump_it;
609
610	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
611	goto out;
612
613	if (!pskb_may_pull(skb, 3))
614	goto dump_it;
615
616	skb_pull(skb, 2);
617
618	if (len > skb->len)
619	goto dump_it;
620
621	skb_trim(skb, len);
622
623	flags = *skb->data;
624
625	cb = DN_SKB_CB(skb);
626	cb->stamp = jiffies;
627	cb->iif = dev->ifindex;
628
629	/*
630	* If we have padding, remove it.
631	*/
632	if (flags & DN_RT_F_PF) {
633	padlen = flags & ~DN_RT_F_PF;
634	if (!pskb_may_pull(skb, padlen + 1))
635	goto dump_it;
636	skb_pull(skb, padlen);
637	flags = *skb->data;
638	}
639
640	skb_reset_network_header(skb);
641
642	/*
643	* Weed out future version DECnet
644	*/
645	if (flags & DN_RT_F_VER)
646	goto dump_it;
647
648	cb->rt_flags = flags;
649
650	if (decnet_debug_level & 1)
651	printk(KERN_DEBUG
652	"dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
653	(int)flags, (dev) ? dev->name : "???", len, skb->len,
654	padlen);
655
656	if (flags & DN_RT_PKT_CNTL) {
657	if (unlikely(skb_linearize(skb)))
658	goto dump_it;
659
660	switch (flags & DN_RT_CNTL_MSK) {
661	case DN_RT_PKT_INIT:
662	dn_dev_init_pkt(skb);
663	break;
664	case DN_RT_PKT_VERI:
665	dn_dev_veri_pkt(skb);
666	break;
667	}
668
669	if (dn->parms.state != DN_DEV_S_RU)
670	goto dump_it;
671
672	switch (flags & DN_RT_CNTL_MSK) {
673	case DN_RT_PKT_HELO:
674	return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
675	skb, skb->dev, NULL,
676	dn_route_ptp_hello);
677
678	case DN_RT_PKT_L1RT:
679	case DN_RT_PKT_L2RT:
680	return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
681	skb, skb->dev, NULL,
682	dn_route_discard);
683	case DN_RT_PKT_ERTH:
684	return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
685	skb, skb->dev, NULL,
686	dn_neigh_router_hello);
687
688	case DN_RT_PKT_EEDH:
689	return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
690	skb, skb->dev, NULL,
691	dn_neigh_endnode_hello);
692	}
693	} else {
694	if (dn->parms.state != DN_DEV_S_RU)
695	goto dump_it;
696
697	skb_pull(skb, 1); /* Pull flags */
698
699	switch (flags & DN_RT_PKT_MSK) {
700	case DN_RT_PKT_LONG:
701	return dn_route_rx_long(skb);
702	case DN_RT_PKT_SHORT:
703	return dn_route_rx_short(skb);
704	}
705	}
706
707	dump_it:
708	kfree_skb(skb);
709	out:
710	return NET_RX_DROP;
711	}
712
713	static int dn_to_neigh_output(struct sk_buff *skb)
714	{
715	struct dst_entry *dst = skb_dst(skb);
716	struct neighbour *n = dst_get_neighbour_noref(dst);
717
718	return n->output(n, skb);
719	}
720
721	static int dn_output(struct sk_buff *skb)
722	{
723	struct dst_entry *dst = skb_dst(skb);
724	struct dn_route rt = (struct dn_route )dst;
725	struct net_device *dev = dst->dev;
726	struct dn_skb_cb *cb = DN_SKB_CB(skb);
727
728	int err = -EINVAL;
729
730	if (dst_get_neighbour_noref(dst) == NULL)
731	goto error;
732
733	skb->dev = dev;
734
735	cb->src = rt->rt_saddr;
736	cb->dst = rt->rt_daddr;
737
738	/*
739	* Always set the Intra-Ethernet bit on all outgoing packets
740	* originated on this node. Only valid flag from upper layers
741	* is return-to-sender-requested. Set hop count to 0 too.
742	*/
743	cb->rt_flags &= ~DN_RT_F_RQR;
744	cb->rt_flags \|= DN_RT_F_IE;
745	cb->hops = 0;
746
747	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
748	dn_to_neigh_output);
749
750	error:
751	if (net_ratelimit())
752	printk(KERN_DEBUG "dn_output: This should not happen\n");
753
754	kfree_skb(skb);
755
756	return err;
757	}
758
759	static int dn_forward(struct sk_buff *skb)
760	{
761	struct dn_skb_cb *cb = DN_SKB_CB(skb);
762	struct dst_entry *dst = skb_dst(skb);
763	struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);
764	struct dn_route *rt;
765	int header_len;
766	#ifdef CONFIG_NETFILTER
767	struct net_device *dev = skb->dev;
768	#endif
769
770	if (skb->pkt_type != PACKET_HOST)
771	goto drop;
772
773	/* Ensure that we have enough space for headers */
774	rt = (struct dn_route *)skb_dst(skb);
775	header_len = dn_db->use_long ? 21 : 6;
776	if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))
777	goto drop;
778
779	/*
780	* Hop count exceeded.
781	*/
782	if (++cb->hops > 30)
783	goto drop;
784
785	skb->dev = rt->dst.dev;
786
787	/*
788	* If packet goes out same interface it came in on, then set
789	* the Intra-Ethernet bit. This has no effect for short
790	* packets, so we don't need to test for them here.
791	*/
792	cb->rt_flags &= ~DN_RT_F_IE;
793	if (rt->rt_flags & RTCF_DOREDIRECT)
794	cb->rt_flags \|= DN_RT_F_IE;
795
796	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
797	dn_to_neigh_output);
798
799	drop:
800	kfree_skb(skb);
801	return NET_RX_DROP;
802	}
803
804	/*
805	* Used to catch bugs. This should never normally get
806	* called.
807	*/
808	static int dn_rt_bug(struct sk_buff *skb)
809	{
810	if (net_ratelimit()) {
811	struct dn_skb_cb *cb = DN_SKB_CB(skb);
812
813	printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
814	le16_to_cpu(cb->src), le16_to_cpu(cb->dst));
815	}
816
817	kfree_skb(skb);
818
819	return NET_RX_DROP;
820	}
821
822	static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
823	{
824	return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
825	}
826
827	static unsigned int dn_dst_mtu(const struct dst_entry *dst)
828	{
829	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
830
831	return mtu ? : dst->dev->mtu;
832	}
833
834	static struct neighbour dn_dst_neigh_lookup(const struct dst_entry dst, const void *daddr)
835	{
836	return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
837	}
838
839	static int dn_rt_set_next_hop(struct dn_route rt, struct dn_fib_res res)
840	{
841	struct dn_fib_info *fi = res->fi;
842	struct net_device *dev = rt->dst.dev;
843	unsigned int mss_metric;
844	struct neighbour *n;
845
846	if (fi) {
847	if (DN_FIB_RES_GW(*res) &&
848	DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
849	rt->rt_gateway = DN_FIB_RES_GW(*res);
850	dst_init_metrics(&rt->dst, fi->fib_metrics, true);
851	}
852	rt->rt_type = res->type;
853
854	if (dev != NULL && dst_get_neighbour_noref(&rt->dst) == NULL) {
855	n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
856	if (IS_ERR(n))
857	return PTR_ERR(n);
858	dst_set_neighbour(&rt->dst, n);
859	}
860
861	if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)
862	dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);
863	mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
864	if (mss_metric) {
865	unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));
866	if (mss_metric > mss)
867	dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
868	}
869	return 0;
870	}
871
872	static inline int dn_match_addr(__le16 addr1, __le16 addr2)
873	{
874	__u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);
875	int match = 16;
876	while(tmp) {
877	tmp >>= 1;
878	match--;
879	}
880	return match;
881	}
882
883	static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
884	{
885	__le16 saddr = 0;
886	struct dn_dev *dn_db;
887	struct dn_ifaddr *ifa;
888	int best_match = 0;
889	int ret;
890
891	rcu_read_lock();
892	dn_db = rcu_dereference(dev->dn_ptr);
893	for (ifa = rcu_dereference(dn_db->ifa_list);
894	ifa != NULL;
895	ifa = rcu_dereference(ifa->ifa_next)) {
896	if (ifa->ifa_scope > scope)
897	continue;
898	if (!daddr) {
899	saddr = ifa->ifa_local;
900	break;
901	}
902	ret = dn_match_addr(daddr, ifa->ifa_local);
903	if (ret > best_match)
904	saddr = ifa->ifa_local;
905	if (best_match == 0)
906	saddr = ifa->ifa_local;
907	}
908	rcu_read_unlock();
909
910	return saddr;
911	}
912
913	static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
914	{
915	return dnet_select_source(DN_FIB_RES_DEV(res), DN_FIB_RES_GW(res), res->scope);
916	}
917
918	static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
919	{
920	__le16 mask = dnet_make_mask(res->prefixlen);
921	return (daddr&~mask)\|res->fi->fib_nh->nh_gw;
922	}
923
924	static int dn_route_output_slow(struct dst_entry *pprt, const struct flowidn oldflp, int try_hard)
925	{
926	struct flowidn fld = {
927	.daddr = oldflp->daddr,
928	.saddr = oldflp->saddr,
929	.flowidn_scope = RT_SCOPE_UNIVERSE,
930	.flowidn_mark = oldflp->flowidn_mark,
931	.flowidn_iif = init_net.loopback_dev->ifindex,
932	.flowidn_oif = oldflp->flowidn_oif,
933	};
934	struct dn_route *rt = NULL;
935	struct net_device dev_out = NULL, dev;
936	struct neighbour *neigh = NULL;
937	unsigned hash;
938	unsigned flags = 0;
939	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
940	int err;
941	int free_res = 0;
942	__le16 gateway = 0;
943
944	if (decnet_debug_level & 16)
945	printk(KERN_DEBUG
946	"dn_route_output_slow: dst=%04x src=%04x mark=%d"
947	" iif=%d oif=%d\n", le16_to_cpu(oldflp->daddr),
948	le16_to_cpu(oldflp->saddr),
949	oldflp->flowidn_mark, init_net.loopback_dev->ifindex,
950	oldflp->flowidn_oif);
951
952	/* If we have an output interface, verify its a DECnet device */
953	if (oldflp->flowidn_oif) {
954	dev_out = dev_get_by_index(&init_net, oldflp->flowidn_oif);
955	err = -ENODEV;
956	if (dev_out && dev_out->dn_ptr == NULL) {
957	dev_put(dev_out);
958	dev_out = NULL;
959	}
960	if (dev_out == NULL)
961	goto out;
962	}
963
964	/* If we have a source address, verify that its a local address */
965	if (oldflp->saddr) {
966	err = -EADDRNOTAVAIL;
967
968	if (dev_out) {
969	if (dn_dev_islocal(dev_out, oldflp->saddr))
970	goto source_ok;
971	dev_put(dev_out);
972	goto out;
973	}
974	rcu_read_lock();
975	for_each_netdev_rcu(&init_net, dev) {
976	if (!dev->dn_ptr)
977	continue;
978	if (!dn_dev_islocal(dev, oldflp->saddr))
979	continue;
980	if ((dev->flags & IFF_LOOPBACK) &&
981	oldflp->daddr &&
982	!dn_dev_islocal(dev, oldflp->daddr))
983	continue;
984
985	dev_out = dev;
986	break;
987	}
988	rcu_read_unlock();
989	if (dev_out == NULL)
990	goto out;
991	dev_hold(dev_out);
992	source_ok:
993	;
994	}
995
996	/* No destination? Assume its local */
997	if (!fld.daddr) {
998	fld.daddr = fld.saddr;
999
1000	err = -EADDRNOTAVAIL;
1001	if (dev_out)
1002	dev_put(dev_out);
1003	dev_out = init_net.loopback_dev;
1004	dev_hold(dev_out);
1005	if (!fld.daddr) {
1006	fld.daddr =
1007	fld.saddr = dnet_select_source(dev_out, 0,
1008	RT_SCOPE_HOST);
1009	if (!fld.daddr)
1010	goto out;
1011	}
1012	fld.flowidn_oif = init_net.loopback_dev->ifindex;
1013	res.type = RTN_LOCAL;
1014	goto make_route;
1015	}
1016
1017	if (decnet_debug_level & 16)
1018	printk(KERN_DEBUG
1019	"dn_route_output_slow: initial checks complete."
1020	" dst=%o4x src=%04x oif=%d try_hard=%d\n",
1021	le16_to_cpu(fld.daddr), le16_to_cpu(fld.saddr),
1022	fld.flowidn_oif, try_hard);
1023
1024	/*
1025	* N.B. If the kernel is compiled without router support then
1026	* dn_fib_lookup() will evaluate to non-zero so this if () block
1027	* will always be executed.
1028	*/
1029	err = -ESRCH;
1030	if (try_hard \|\| (err = dn_fib_lookup(&fld, &res)) != 0) {
1031	struct dn_dev *dn_db;
1032	if (err != -ESRCH)
1033	goto out;
1034	/*
1035	* Here the fallback is basically the standard algorithm for
1036	* routing in endnodes which is described in the DECnet routing
1037	* docs
1038	*
1039	* If we are not trying hard, look in neighbour cache.
1040	* The result is tested to ensure that if a specific output
1041	* device/source address was requested, then we honour that
1042	* here
1043	*/
1044	if (!try_hard) {
1045	neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fld.daddr);
1046	if (neigh) {
1047	if ((oldflp->flowidn_oif &&
1048	(neigh->dev->ifindex != oldflp->flowidn_oif)) \|\|
1049	(oldflp->saddr &&
1050	(!dn_dev_islocal(neigh->dev,
1051	oldflp->saddr)))) {
1052	neigh_release(neigh);
1053	neigh = NULL;
1054	} else {
1055	if (dev_out)
1056	dev_put(dev_out);
1057	if (dn_dev_islocal(neigh->dev, fld.daddr)) {
1058	dev_out = init_net.loopback_dev;
1059	res.type = RTN_LOCAL;
1060	} else {
1061	dev_out = neigh->dev;
1062	}
1063	dev_hold(dev_out);
1064	goto select_source;
1065	}
1066	}
1067	}
1068
1069	/* Not there? Perhaps its a local address */
1070	if (dev_out == NULL)
1071	dev_out = dn_dev_get_default();
1072	err = -ENODEV;
1073	if (dev_out == NULL)
1074	goto out;
1075	dn_db = rcu_dereference_raw(dev_out->dn_ptr);
1076	/* Possible improvement - check all devices for local addr */
1077	if (dn_dev_islocal(dev_out, fld.daddr)) {
1078	dev_put(dev_out);
1079	dev_out = init_net.loopback_dev;
1080	dev_hold(dev_out);
1081	res.type = RTN_LOCAL;
1082	goto select_source;
1083	}
1084	/* Not local either.... try sending it to the default router */
1085	neigh = neigh_clone(dn_db->router);
1086	BUG_ON(neigh && neigh->dev != dev_out);
1087
1088	/* Ok then, we assume its directly connected and move on */
1089	select_source:
1090	if (neigh)
1091	gateway = ((struct dn_neigh *)neigh)->addr;
1092	if (gateway == 0)
1093	gateway = fld.daddr;
1094	if (fld.saddr == 0) {
1095	fld.saddr = dnet_select_source(dev_out, gateway,
1096	res.type == RTN_LOCAL ?
1097	RT_SCOPE_HOST :
1098	RT_SCOPE_LINK);
1099	if (fld.saddr == 0 && res.type != RTN_LOCAL)
1100	goto e_addr;
1101	}
1102	fld.flowidn_oif = dev_out->ifindex;
1103	goto make_route;
1104	}
1105	free_res = 1;
1106
1107	if (res.type == RTN_NAT)
1108	goto e_inval;
1109
1110	if (res.type == RTN_LOCAL) {
1111	if (!fld.saddr)
1112	fld.saddr = fld.daddr;
1113	if (dev_out)
1114	dev_put(dev_out);
1115	dev_out = init_net.loopback_dev;
1116	dev_hold(dev_out);
1117	fld.flowidn_oif = dev_out->ifindex;
1118	if (res.fi)
1119	dn_fib_info_put(res.fi);
1120	res.fi = NULL;
1121	goto make_route;
1122	}
1123
1124	if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1125	dn_fib_select_multipath(&fld, &res);
1126
1127	/*
1128	* We could add some logic to deal with default routes here and
1129	* get rid of some of the special casing above.
1130	*/
1131
1132	if (!fld.saddr)
1133	fld.saddr = DN_FIB_RES_PREFSRC(res);
1134
1135	if (dev_out)
1136	dev_put(dev_out);
1137	dev_out = DN_FIB_RES_DEV(res);
1138	dev_hold(dev_out);
1139	fld.flowidn_oif = dev_out->ifindex;
1140	gateway = DN_FIB_RES_GW(res);
1141
1142	make_route:
1143	if (dev_out->flags & IFF_LOOPBACK)
1144	flags \|= RTCF_LOCAL;
1145
1146	rt = dst_alloc(&dn_dst_ops, dev_out, 1, 0, DST_HOST);
1147	if (rt == NULL)
1148	goto e_nobufs;
1149
1150	memset(&rt->fld, 0, sizeof(rt->fld));
1151	rt->fld.saddr = oldflp->saddr;
1152	rt->fld.daddr = oldflp->daddr;
1153	rt->fld.flowidn_oif = oldflp->flowidn_oif;
1154	rt->fld.flowidn_iif = 0;
1155	rt->fld.flowidn_mark = oldflp->flowidn_mark;
1156
1157	rt->rt_saddr = fld.saddr;
1158	rt->rt_daddr = fld.daddr;
1159	rt->rt_gateway = gateway ? gateway : fld.daddr;
1160	rt->rt_local_src = fld.saddr;
1161
1162	rt->rt_dst_map = fld.daddr;
1163	rt->rt_src_map = fld.saddr;
1164
1165	dst_set_neighbour(&rt->dst, neigh);
1166	neigh = NULL;
1167
1168	rt->dst.lastuse = jiffies;
1169	rt->dst.output = dn_output;
1170	rt->dst.input = dn_rt_bug;
1171	rt->rt_flags = flags;
1172	if (flags & RTCF_LOCAL)
1173	rt->dst.input = dn_nsp_rx;
1174
1175	err = dn_rt_set_next_hop(rt, &res);
1176	if (err)
1177	goto e_neighbour;
1178
1179	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1180	dn_insert_route(rt, hash, (struct dn_route **)pprt);
1181
1182	done:
1183	if (neigh)
1184	neigh_release(neigh);
1185	if (free_res)
1186	dn_fib_res_put(&res);
1187	if (dev_out)
1188	dev_put(dev_out);
1189	out:
1190	return err;
1191
1192	e_addr:
1193	err = -EADDRNOTAVAIL;
1194	goto done;
1195	e_inval:
1196	err = -EINVAL;
1197	goto done;
1198	e_nobufs:
1199	err = -ENOBUFS;
1200	goto done;
1201	e_neighbour:
1202	dst_free(&rt->dst);
1203	goto e_nobufs;
1204	}
1205
1206
1207	/*
1208	* N.B. The flags may be moved into the flowi at some future stage.
1209	*/
1210	static int __dn_route_output_key(struct dst_entry *pprt, const struct flowidn flp, int flags)
1211	{
1212	unsigned hash = dn_hash(flp->saddr, flp->daddr);
1213	struct dn_route *rt = NULL;
1214
1215	if (!(flags & MSG_TRYHARD)) {
1216	rcu_read_lock_bh();
1217	for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;
1218	rt = rcu_dereference_bh(rt->dst.dn_next)) {
1219	if ((flp->daddr == rt->fld.daddr) &&
1220	(flp->saddr == rt->fld.saddr) &&
1221	(flp->flowidn_mark == rt->fld.flowidn_mark) &&
1222	dn_is_output_route(rt) &&
1223	(rt->fld.flowidn_oif == flp->flowidn_oif)) {
1224	dst_use(&rt->dst, jiffies);
1225	rcu_read_unlock_bh();
1226	*pprt = &rt->dst;
1227	return 0;
1228	}
1229	}
1230	rcu_read_unlock_bh();
1231	}
1232
1233	return dn_route_output_slow(pprt, flp, flags);
1234	}
1235
1236	static int dn_route_output_key(struct dst_entry *pprt, struct flowidn flp, int flags)
1237	{
1238	int err;
1239
1240	err = __dn_route_output_key(pprt, flp, flags);
1241	if (err == 0 && flp->flowidn_proto) {
1242	pprt = xfrm_lookup(&init_net, pprt,
1243	flowidn_to_flowi(flp), NULL, 0);
1244	if (IS_ERR(*pprt)) {
1245	err = PTR_ERR(*pprt);
1246	*pprt = NULL;
1247	}
1248	}
1249	return err;
1250	}
1251
1252	int dn_route_output_sock(struct dst_entry *pprt, struct flowidn fl, struct sock *sk, int flags)
1253	{
1254	int err;
1255
1256	err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1257	if (err == 0 && fl->flowidn_proto) {
1258	if (!(flags & MSG_DONTWAIT))
1259	fl->flowidn_flags \|= FLOWI_FLAG_CAN_SLEEP;
1260	pprt = xfrm_lookup(&init_net, pprt,
1261	flowidn_to_flowi(fl), sk, 0);
1262	if (IS_ERR(*pprt)) {
1263	err = PTR_ERR(*pprt);
1264	*pprt = NULL;
1265	}
1266	}
1267	return err;
1268	}
1269
1270	static int dn_route_input_slow(struct sk_buff *skb)
1271	{
1272	struct dn_route *rt = NULL;
1273	struct dn_skb_cb *cb = DN_SKB_CB(skb);
1274	struct net_device *in_dev = skb->dev;
1275	struct net_device *out_dev = NULL;
1276	struct dn_dev *dn_db;
1277	struct neighbour *neigh = NULL;
1278	unsigned hash;
1279	int flags = 0;
1280	__le16 gateway = 0;
1281	__le16 local_src = 0;
1282	struct flowidn fld = {
1283	.daddr = cb->dst,
1284	.saddr = cb->src,
1285	.flowidn_scope = RT_SCOPE_UNIVERSE,
1286	.flowidn_mark = skb->mark,
1287	.flowidn_iif = skb->dev->ifindex,
1288	};
1289	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1290	int err = -EINVAL;
1291	int free_res = 0;
1292
1293	dev_hold(in_dev);
1294
1295	if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)
1296	goto out;
1297
1298	/* Zero source addresses are not allowed */
1299	if (fld.saddr == 0)
1300	goto out;
1301
1302	/*
1303	* In this case we've just received a packet from a source
1304	* outside ourselves pretending to come from us. We don't
1305	* allow it any further to prevent routing loops, spoofing and
1306	* other nasties. Loopback packets already have the dst attached
1307	* so this only affects packets which have originated elsewhere.
1308	*/
1309	err = -ENOTUNIQ;
1310	if (dn_dev_islocal(in_dev, cb->src))
1311	goto out;
1312
1313	err = dn_fib_lookup(&fld, &res);
1314	if (err) {
1315	if (err != -ESRCH)
1316	goto out;
1317	/*
1318	* Is the destination us ?
1319	*/
1320	if (!dn_dev_islocal(in_dev, cb->dst))
1321	goto e_inval;
1322
1323	res.type = RTN_LOCAL;
1324	} else {
1325	__le16 src_map = fld.saddr;
1326	free_res = 1;
1327
1328	out_dev = DN_FIB_RES_DEV(res);
1329	if (out_dev == NULL) {
1330	if (net_ratelimit())
1331	printk(KERN_CRIT "Bug in dn_route_input_slow() "
1332	"No output device\n");
1333	goto e_inval;
1334	}
1335	dev_hold(out_dev);
1336
1337	if (res.r)
1338	src_map = fld.saddr; /* no NAT support for now */
1339
1340	gateway = DN_FIB_RES_GW(res);
1341	if (res.type == RTN_NAT) {
1342	fld.daddr = dn_fib_rules_map_destination(fld.daddr, &res);
1343	dn_fib_res_put(&res);
1344	free_res = 0;
1345	if (dn_fib_lookup(&fld, &res))
1346	goto e_inval;
1347	free_res = 1;
1348	if (res.type != RTN_UNICAST)
1349	goto e_inval;
1350	flags \|= RTCF_DNAT;
1351	gateway = fld.daddr;
1352	}
1353	fld.saddr = src_map;
1354	}
1355
1356	switch(res.type) {
1357	case RTN_UNICAST:
1358	/*
1359	* Forwarding check here, we only check for forwarding
1360	* being turned off, if you want to only forward intra
1361	* area, its up to you to set the routing tables up
1362	* correctly.
1363	*/
1364	if (dn_db->parms.forwarding == 0)
1365	goto e_inval;
1366
1367	if (res.fi->fib_nhs > 1 && fld.flowidn_oif == 0)
1368	dn_fib_select_multipath(&fld, &res);
1369
1370	/*
1371	* Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1372	* flag as a hint to set the intra-ethernet bit when
1373	* forwarding. If we've got NAT in operation, we don't do
1374	* this optimisation.
1375	*/
1376	if (out_dev == in_dev && !(flags & RTCF_NAT))
1377	flags \|= RTCF_DOREDIRECT;
1378
1379	local_src = DN_FIB_RES_PREFSRC(res);
1380
1381	case RTN_BLACKHOLE:
1382	case RTN_UNREACHABLE:
1383	break;
1384	case RTN_LOCAL:
1385	flags \|= RTCF_LOCAL;
1386	fld.saddr = cb->dst;
1387	fld.daddr = cb->src;
1388
1389	/* Routing tables gave us a gateway */
1390	if (gateway)
1391	goto make_route;
1392
1393	/* Packet was intra-ethernet, so we know its on-link */
1394	if (cb->rt_flags & DN_RT_F_IE) {
1395	gateway = cb->src;
1396	flags \|= RTCF_DIRECTSRC;
1397	goto make_route;
1398	}
1399
1400	/* Use the default router if there is one */
1401	neigh = neigh_clone(dn_db->router);
1402	if (neigh) {
1403	gateway = ((struct dn_neigh *)neigh)->addr;
1404	goto make_route;
1405	}
1406
1407	/* Close eyes and pray */
1408	gateway = cb->src;
1409	flags \|= RTCF_DIRECTSRC;
1410	goto make_route;
1411	default:
1412	goto e_inval;
1413	}
1414
1415	make_route:
1416	rt = dst_alloc(&dn_dst_ops, out_dev, 0, 0, DST_HOST);
1417	if (rt == NULL)
1418	goto e_nobufs;
1419
1420	memset(&rt->fld, 0, sizeof(rt->fld));
1421	rt->rt_saddr = fld.saddr;
1422	rt->rt_daddr = fld.daddr;
1423	rt->rt_gateway = fld.daddr;
1424	if (gateway)
1425	rt->rt_gateway = gateway;
1426	rt->rt_local_src = local_src ? local_src : rt->rt_saddr;
1427
1428	rt->rt_dst_map = fld.daddr;
1429	rt->rt_src_map = fld.saddr;
1430
1431	rt->fld.saddr = cb->src;
1432	rt->fld.daddr = cb->dst;
1433	rt->fld.flowidn_oif = 0;
1434	rt->fld.flowidn_iif = in_dev->ifindex;
1435	rt->fld.flowidn_mark = fld.flowidn_mark;
1436
1437	dst_set_neighbour(&rt->dst, neigh);
1438	rt->dst.lastuse = jiffies;
1439	rt->dst.output = dn_rt_bug;
1440	switch (res.type) {
1441	case RTN_UNICAST:
1442	rt->dst.input = dn_forward;
1443	break;
1444	case RTN_LOCAL:
1445	rt->dst.output = dn_output;
1446	rt->dst.input = dn_nsp_rx;
1447	rt->dst.dev = in_dev;
1448	flags \|= RTCF_LOCAL;
1449	break;
1450	default:
1451	case RTN_UNREACHABLE:
1452	case RTN_BLACKHOLE:
1453	rt->dst.input = dst_discard;
1454	}
1455	rt->rt_flags = flags;
1456
1457	err = dn_rt_set_next_hop(rt, &res);
1458	if (err)
1459	goto e_neighbour;
1460
1461	hash = dn_hash(rt->fld.saddr, rt->fld.daddr);
1462	dn_insert_route(rt, hash, &rt);
1463	skb_dst_set(skb, &rt->dst);
1464
1465	done:
1466	if (neigh)
1467	neigh_release(neigh);
1468	if (free_res)
1469	dn_fib_res_put(&res);
1470	dev_put(in_dev);
1471	if (out_dev)
1472	dev_put(out_dev);
1473	out:
1474	return err;
1475
1476	e_inval:
1477	err = -EINVAL;
1478	goto done;
1479
1480	e_nobufs:
1481	err = -ENOBUFS;
1482	goto done;
1483
1484	e_neighbour:
1485	dst_free(&rt->dst);
1486	goto done;
1487	}
1488
1489	static int dn_route_input(struct sk_buff *skb)
1490	{
1491	struct dn_route *rt;
1492	struct dn_skb_cb *cb = DN_SKB_CB(skb);
1493	unsigned hash = dn_hash(cb->src, cb->dst);
1494
1495	if (skb_dst(skb))
1496	return 0;
1497
1498	rcu_read_lock();
1499	for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1500	rt = rcu_dereference(rt->dst.dn_next)) {
1501	if ((rt->fld.saddr == cb->src) &&
1502	(rt->fld.daddr == cb->dst) &&
1503	(rt->fld.flowidn_oif == 0) &&
1504	(rt->fld.flowidn_mark == skb->mark) &&
1505	(rt->fld.flowidn_iif == cb->iif)) {
1506	dst_use(&rt->dst, jiffies);
1507	rcu_read_unlock();
1508	skb_dst_set(skb, (struct dst_entry *)rt);
1509	return 0;
1510	}
1511	}
1512	rcu_read_unlock();
1513
1514	return dn_route_input_slow(skb);
1515	}
1516
1517	static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1518	int event, int nowait, unsigned int flags)
1519	{
1520	struct dn_route rt = (struct dn_route )skb_dst(skb);
1521	struct rtmsg *r;
1522	struct nlmsghdr *nlh;
1523	unsigned char *b = skb_tail_pointer(skb);
1524	long expires;
1525
1526	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1527	r = NLMSG_DATA(nlh);
1528	r->rtm_family = AF_DECnet;
1529	r->rtm_dst_len = 16;
1530	r->rtm_src_len = 0;
1531	r->rtm_tos = 0;
1532	r->rtm_table = RT_TABLE_MAIN;
1533	RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);
1534	r->rtm_type = rt->rt_type;
1535	r->rtm_flags = (rt->rt_flags & ~0xFFFF) \| RTM_F_CLONED;
1536	r->rtm_scope = RT_SCOPE_UNIVERSE;
1537	r->rtm_protocol = RTPROT_UNSPEC;
1538	if (rt->rt_flags & RTCF_NOTIFY)
1539	r->rtm_flags \|= RTM_F_NOTIFY;
1540	RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1541	if (rt->fld.saddr) {
1542	r->rtm_src_len = 16;
1543	RTA_PUT(skb, RTA_SRC, 2, &rt->fld.saddr);
1544	}
1545	if (rt->dst.dev)
1546	RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->dst.dev->ifindex);
1547	/*
1548	* Note to self - change this if input routes reverse direction when
1549	* they deal only with inputs and not with replies like they do
1550	* currently.
1551	*/
1552	RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1553	if (rt->rt_daddr != rt->rt_gateway)
1554	RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1555	if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)
1556	goto rtattr_failure;
1557	expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
1558	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, 0, 0, expires,
1559	rt->dst.error) < 0)
1560	goto rtattr_failure;
1561	if (dn_is_input_route(rt))
1562	RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fld.flowidn_iif);
1563
1564	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
1565	return skb->len;
1566
1567	nlmsg_failure:
1568	rtattr_failure:
1569	nlmsg_trim(skb, b);
1570	return -1;
1571	}
1572
1573	/*
1574	* This is called by both endnodes and routers now.
1575	*/
1576	static int dn_cache_getroute(struct sk_buff in_skb, struct nlmsghdr nlh, void *arg)
1577	{
1578	struct net *net = sock_net(in_skb->sk);
1579	struct rtattr **rta = arg;
1580	struct rtmsg *rtm = NLMSG_DATA(nlh);
1581	struct dn_route *rt = NULL;
1582	struct dn_skb_cb *cb;
1583	int err;
1584	struct sk_buff *skb;
1585	struct flowidn fld;
1586
1587	if (!net_eq(net, &init_net))
1588	return -EINVAL;
1589
1590	memset(&fld, 0, sizeof(fld));
1591	fld.flowidn_proto = DNPROTO_NSP;
1592
1593	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1594	if (skb == NULL)
1595	return -ENOBUFS;
1596	skb_reset_mac_header(skb);
1597	cb = DN_SKB_CB(skb);
1598
1599	if (rta[RTA_SRC-1])
1600	memcpy(&fld.saddr, RTA_DATA(rta[RTA_SRC-1]), 2);
1601	if (rta[RTA_DST-1])
1602	memcpy(&fld.daddr, RTA_DATA(rta[RTA_DST-1]), 2);
1603	if (rta[RTA_IIF-1])
1604	memcpy(&fld.flowidn_iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1605
1606	if (fld.flowidn_iif) {
1607	struct net_device *dev;
1608	if ((dev = dev_get_by_index(&init_net, fld.flowidn_iif)) == NULL) {
1609	kfree_skb(skb);
1610	return -ENODEV;
1611	}
1612	if (!dev->dn_ptr) {
1613	dev_put(dev);
1614	kfree_skb(skb);
1615	return -ENODEV;
1616	}
1617	skb->protocol = htons(ETH_P_DNA_RT);
1618	skb->dev = dev;
1619	cb->src = fld.saddr;
1620	cb->dst = fld.daddr;
1621	local_bh_disable();
1622	err = dn_route_input(skb);
1623	local_bh_enable();
1624	memset(cb, 0, sizeof(struct dn_skb_cb));
1625	rt = (struct dn_route *)skb_dst(skb);
1626	if (!err && -rt->dst.error)
1627	err = rt->dst.error;
1628	} else {
1629	int oif = 0;
1630	if (rta[RTA_OIF - 1])
1631	memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1632	fld.flowidn_oif = oif;
1633	err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
1634	}
1635
1636	if (skb->dev)
1637	dev_put(skb->dev);
1638	skb->dev = NULL;
1639	if (err)
1640	goto out_free;
1641	skb_dst_set(skb, &rt->dst);
1642	if (rtm->rtm_flags & RTM_F_NOTIFY)
1643	rt->rt_flags \|= RTCF_NOTIFY;
1644
1645	err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1646
1647	if (err == 0)
1648	goto out_free;
1649	if (err < 0) {
1650	err = -EMSGSIZE;
1651	goto out_free;
1652	}
1653
1654	return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);
1655
1656	out_free:
1657	kfree_skb(skb);
1658	return err;
1659	}
1660
1661	/*
1662	* For routers, this is called from dn_fib_dump, but for endnodes its
1663	* called directly from the rtnetlink dispatch table.
1664	*/
1665	int dn_cache_dump(struct sk_buff skb, struct netlink_callback cb)
1666	{
1667	struct net *net = sock_net(skb->sk);
1668	struct dn_route *rt;
1669	int h, s_h;
1670	int idx, s_idx;
1671
1672	if (!net_eq(net, &init_net))
1673	return 0;
1674
1675	if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1676	return -EINVAL;
1677	if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1678	return 0;
1679
1680	s_h = cb->args[0];
1681	s_idx = idx = cb->args[1];
1682	for(h = 0; h <= dn_rt_hash_mask; h++) {
1683	if (h < s_h)
1684	continue;
1685	if (h > s_h)
1686	s_idx = 0;
1687	rcu_read_lock_bh();
1688	for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;
1689	rt;
1690	rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {
1691	if (idx < s_idx)
1692	continue;
1693	skb_dst_set(skb, dst_clone(&rt->dst));
1694	if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1695	cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1696	1, NLM_F_MULTI) <= 0) {
1697	skb_dst_drop(skb);
1698	rcu_read_unlock_bh();
1699	goto done;
1700	}
1701	skb_dst_drop(skb);
1702	}
1703	rcu_read_unlock_bh();
1704	}
1705
1706	done:
1707	cb->args[0] = h;
1708	cb->args[1] = idx;
1709	return skb->len;
1710	}
1711
1712	#ifdef CONFIG_PROC_FS
1713	struct dn_rt_cache_iter_state {
1714	int bucket;
1715	};
1716
1717	static struct dn_route dn_rt_cache_get_first(struct seq_file seq)
1718	{
1719	struct dn_route *rt = NULL;
1720	struct dn_rt_cache_iter_state *s = seq->private;
1721
1722	for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1723	rcu_read_lock_bh();
1724	rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1725	if (rt)
1726	break;
1727	rcu_read_unlock_bh();
1728	}
1729	return rt;
1730	}
1731
1732	static struct dn_route dn_rt_cache_get_next(struct seq_file seq, struct dn_route *rt)
1733	{
1734	struct dn_rt_cache_iter_state *s = seq->private;
1735
1736	rt = rcu_dereference_bh(rt->dst.dn_next);
1737	while (!rt) {
1738	rcu_read_unlock_bh();
1739	if (--s->bucket < 0)
1740	break;
1741	rcu_read_lock_bh();
1742	rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);
1743	}
1744	return rt;
1745	}
1746
1747	static void dn_rt_cache_seq_start(struct seq_file seq, loff_t *pos)
1748	{
1749	struct dn_route *rt = dn_rt_cache_get_first(seq);
1750
1751	if (rt) {
1752	while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1753	--*pos;
1754	}
1755	return *pos ? NULL : rt;
1756	}
1757
1758	static void dn_rt_cache_seq_next(struct seq_file seq, void v, loff_t pos)
1759	{
1760	struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1761	++*pos;
1762	return rt;
1763	}
1764
1765	static void dn_rt_cache_seq_stop(struct seq_file seq, void v)
1766	{
1767	if (v)
1768	rcu_read_unlock_bh();
1769	}
1770
1771	static int dn_rt_cache_seq_show(struct seq_file seq, void v)
1772	{
1773	struct dn_route *rt = v;
1774	char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1775
1776	seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1777	rt->dst.dev ? rt->dst.dev->name : "*",
1778	dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
1779	dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),
1780	atomic_read(&rt->dst.__refcnt),
1781	rt->dst.__use,
1782	(int) dst_metric(&rt->dst, RTAX_RTT));
1783	return 0;
1784	}
1785
1786	static const struct seq_operations dn_rt_cache_seq_ops = {
1787	.start = dn_rt_cache_seq_start,
1788	.next = dn_rt_cache_seq_next,
1789	.stop = dn_rt_cache_seq_stop,
1790	.show = dn_rt_cache_seq_show,
1791	};
1792
1793	static int dn_rt_cache_seq_open(struct inode inode, struct file file)
1794	{
1795	return seq_open_private(file, &dn_rt_cache_seq_ops,
1796	sizeof(struct dn_rt_cache_iter_state));
1797	}
1798
1799	static const struct file_operations dn_rt_cache_seq_fops = {
1800	.owner = THIS_MODULE,
1801	.open = dn_rt_cache_seq_open,
1802	.read = seq_read,
1803	.llseek = seq_lseek,
1804	.release = seq_release_private,
1805	};
1806
1807	#endif /* CONFIG_PROC_FS */
1808
1809	void __init dn_route_init(void)
1810	{
1811	int i, goal, order;
1812
1813	dn_dst_ops.kmem_cachep =
1814	kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,
1815	SLAB_HWCACHE_ALIGN\|SLAB_PANIC, NULL);
1816	dst_entries_init(&dn_dst_ops);
1817	setup_timer(&dn_route_timer, dn_dst_check_expire, 0);
1818	dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1819	add_timer(&dn_route_timer);
1820
1821	goal = totalram_pages >> (26 - PAGE_SHIFT);
1822
1823	for(order = 0; (1UL << order) < goal; order++)
1824	/* NOTHING */;
1825
1826	/*
1827	* Only want 1024 entries max, since the table is very, very unlikely
1828	* to be larger than that.
1829	*/
1830	while(order && ((((1UL << order) * PAGE_SIZE) /
1831	sizeof(struct dn_rt_hash_bucket)) >= 2048))
1832	order--;
1833
1834	do {
1835	dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1836	sizeof(struct dn_rt_hash_bucket);
1837	while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1838	dn_rt_hash_mask--;
1839	dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1840	__get_free_pages(GFP_ATOMIC, order);
1841	} while (dn_rt_hash_table == NULL && --order > 0);
1842
1843	if (!dn_rt_hash_table)
1844	panic("Failed to allocate DECnet route cache hash table\n");
1845
1846	printk(KERN_INFO
1847	"DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1848	dn_rt_hash_mask,
1849	(long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1850
1851	dn_rt_hash_mask--;
1852	for(i = 0; i <= dn_rt_hash_mask; i++) {
1853	spin_lock_init(&dn_rt_hash_table[i].lock);
1854	dn_rt_hash_table[i].chain = NULL;
1855	}
1856
1857	dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1858
1859	proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1860
1861	#ifdef CONFIG_DECNET_ROUTER
1862	rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1863	dn_fib_dump, NULL);
1864	#else
1865	rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
1866	dn_cache_dump, NULL);
1867	#endif
1868	}
1869
1870	void __exit dn_route_cleanup(void)
1871	{
1872	del_timer(&dn_route_timer);
1873	dn_run_flush(0);
1874
1875	proc_net_remove(&init_net, "decnet_cache");
1876	dst_entries_destroy(&dn_dst_ops);
1877	}
1878
1879

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