/*
   * DECnet       An implementation of the DECnet protocol suite for the LINUX
   *              operating system.  DECnet is implemented using the  BSD Socket
   *              interface as the means of communication with the user level.
   *
   *              DECnet Routing Functions (Endnode and Router)
   *
   * Authors:     Steve Whitehouse <SteveW@ACM.org>
   *              Eduardo Marcelo Serrat <emserrat@geocities.com>
   *
   * Changes:
   *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
   *                                 "return-to-sender" bits on outgoing
   *                                 packets.
   *		Steve Whitehouse : Timeouts for cached routes.
   *              Steve Whitehouse : Use dst cache for input routes too.
   *              Steve Whitehouse : Fixed error values in dn_send_skb.
   *              Steve Whitehouse : Rework routing functions to better fit
   *                                 DECnet routing design
   *              Alexey Kuznetsov : New SMP locking
   *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
   *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
   *				   Fixed possible skb leak in rtnetlink funcs.
   *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
   *                                 Alexey Kuznetsov's finer grained locking
   *                                 from ipv4/route.c.
   *              Steve Whitehouse : Routing is now starting to look like a
   *                                 sensible set of code now, mainly due to
   *                                 my copying the IPv4 routing code. The
   *                                 hooks here are modified and will continue
   *                                 to evolve for a while.
   *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
   *                                 stuff. Look out raw sockets your days
   *                                 are numbered!
   *              Steve Whitehouse : Added return-to-sender functions. Added
   *                                 backlog congestion level return codes.
   *		Steve Whitehouse : Fixed bug where routes were set up with
   *                                 no ref count on net devices.
   *              Steve Whitehouse : RCU for the route cache
   *              Steve Whitehouse : Preparations for the flow cache
   *              Steve Whitehouse : Prepare for nonlinear skbs
   */
  
  /******************************************************************************
      (c) 1995-1998 E.M. Serrat		emserrat@geocities.com

      This program is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published by
      the Free Software Foundation; either version 2 of the License, or
      any later version.
  
      This program is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      GNU General Public License for more details.
  *******************************************************************************/

  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/socket.h>
  #include <linux/in.h>
  #include <linux/kernel.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/netdevice.h>
  #include <linux/inet.h>
  #include <linux/route.h>
  #include <linux/in_route.h>

  #include <linux/slab.h>

  #include <net/sock.h>
  #include <linux/mm.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/init.h>
  #include <linux/rtnetlink.h>
  #include <linux/string.h>
  #include <linux/netfilter_decnet.h>
  #include <linux/rcupdate.h>
  #include <linux/times.h>
  #include <asm/errno.h>

  #include <net/net_namespace.h>

  #include <net/netlink.h>

  #include <net/neighbour.h>
  #include <net/dst.h>
  #include <net/flow.h>

  #include <net/fib_rules.h>

  #include <net/dn.h>
  #include <net/dn_dev.h>
  #include <net/dn_nsp.h>
  #include <net/dn_route.h>
  #include <net/dn_neigh.h>
  #include <net/dn_fib.h>
  
  struct dn_rt_hash_bucket
  {

  	struct dn_route __rcu *chain;

  	spinlock_t lock;

  };

  
  extern struct neigh_table dn_neigh_table;
  
  
  static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
  
  static const int dn_rt_min_delay = 2 * HZ;
  static const int dn_rt_max_delay = 10 * HZ;
  static const int dn_rt_mtu_expires = 10 * 60 * HZ;
  
  static unsigned long dn_rt_deadline;

  static int dn_dst_gc(struct dst_ops *ops);

  static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);

  static unsigned int dn_dst_default_advmss(const struct dst_entry *dst);

  static unsigned int dn_dst_default_mtu(const struct dst_entry *dst);

  static void dn_dst_destroy(struct dst_entry *);

  static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
  static void dn_dst_link_failure(struct sk_buff *);
  static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
  static int dn_route_input(struct sk_buff *);
  static void dn_run_flush(unsigned long dummy);
  
  static struct dn_rt_hash_bucket *dn_rt_hash_table;
  static unsigned dn_rt_hash_mask;
  
  static struct timer_list dn_route_timer;

  static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);

  int decnet_dst_gc_interval = 2;
  
  static struct dst_ops dn_dst_ops = {
  	.family =		PF_DECnet,

  	.protocol =		cpu_to_be16(ETH_P_DNA_RT),

  	.gc_thresh =		128,
  	.gc =			dn_dst_gc,
  	.check =		dn_dst_check,

  	.default_advmss =	dn_dst_default_advmss,

  	.default_mtu =		dn_dst_default_mtu,

  	.cow_metrics =		dst_cow_metrics_generic,
  	.destroy =		dn_dst_destroy,

  	.negative_advice =	dn_dst_negative_advice,
  	.link_failure =		dn_dst_link_failure,
  	.update_pmtu =		dn_dst_update_pmtu,

  };

  static void dn_dst_destroy(struct dst_entry *dst)
  {
  	dst_destroy_metrics_generic(dst);
  }

  static __inline__ unsigned dn_hash(__le16 src, __le16 dst)

  {

  	__u16 tmp = (__u16 __force)(src ^ dst);

  	tmp ^= (tmp >> 3);
  	tmp ^= (tmp >> 5);
  	tmp ^= (tmp >> 10);
  	return dn_rt_hash_mask & (unsigned)tmp;
  }
  
  static inline void dnrt_free(struct dn_route *rt)
  {

  	call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);

  }
  
  static inline void dnrt_drop(struct dn_route *rt)
  {

  	dst_release(&rt->dst);
  	call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);

  }
  
  static void dn_dst_check_expire(unsigned long dummy)
  {
  	int i;

  	struct dn_route *rt;
  	struct dn_route __rcu **rtp;

  	unsigned long now = jiffies;
  	unsigned long expire = 120 * HZ;

  	for (i = 0; i <= dn_rt_hash_mask; i++) {

  		rtp = &dn_rt_hash_table[i].chain;
  
  		spin_lock(&dn_rt_hash_table[i].lock);

  		while ((rt = rcu_dereference_protected(*rtp,
  						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {

  			if (atomic_read(&rt->dst.__refcnt) ||
  					(now - rt->dst.lastuse) < expire) {
  				rtp = &rt->dst.dn_next;

  				continue;
  			}

  			*rtp = rt->dst.dn_next;
  			rt->dst.dn_next = NULL;

  			dnrt_free(rt);
  		}
  		spin_unlock(&dn_rt_hash_table[i].lock);
  
  		if ((jiffies - now) > 0)
  			break;
  	}
  
  	mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
  }

  static int dn_dst_gc(struct dst_ops *ops)

  {

  	struct dn_route *rt;
  	struct dn_route __rcu **rtp;

  	int i;
  	unsigned long now = jiffies;
  	unsigned long expire = 10 * HZ;

  	for (i = 0; i <= dn_rt_hash_mask; i++) {

  
  		spin_lock_bh(&dn_rt_hash_table[i].lock);
  		rtp = &dn_rt_hash_table[i].chain;

  		while ((rt = rcu_dereference_protected(*rtp,
  						lockdep_is_held(&dn_rt_hash_table[i].lock))) != NULL) {

  			if (atomic_read(&rt->dst.__refcnt) ||
  					(now - rt->dst.lastuse) < expire) {
  				rtp = &rt->dst.dn_next;

  				continue;
  			}

  			*rtp = rt->dst.dn_next;
  			rt->dst.dn_next = NULL;

  			dnrt_drop(rt);
  			break;
  		}
  		spin_unlock_bh(&dn_rt_hash_table[i].lock);
  	}
  
  	return 0;
  }
  
  /*
   * The decnet standards don't impose a particular minimum mtu, what they
   * do insist on is that the routing layer accepts a datagram of at least
   * 230 bytes long. Here we have to subtract the routing header length from
   * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
   * assume the worst and use a long header size.
   *
   * We update both the mtu and the advertised mss (i.e. the segment size we
   * advertise to the other end).
   */
  static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
  {
  	u32 min_mtu = 230;
  	struct dn_dev *dn = dst->neighbour ?

  			    rcu_dereference_raw(dst->neighbour->dev->dn_ptr) : NULL;

  
  	if (dn && dn->use_long == 0)
  		min_mtu -= 6;
  	else
  		min_mtu -= 21;

  	if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= min_mtu) {

  		if (!(dst_metric_locked(dst, RTAX_MTU))) {

  			dst_metric_set(dst, RTAX_MTU, mtu);

  			dst_set_expires(dst, dn_rt_mtu_expires);
  		}
  		if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
  			u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;

  			u32 existing_mss = dst_metric_raw(dst, RTAX_ADVMSS);
  			if (!existing_mss || existing_mss > mss)

  				dst_metric_set(dst, RTAX_ADVMSS, mss);

  		}
  	}
  }

  /*

   * When a route has been marked obsolete. (e.g. routing cache flush)
   */
  static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
  {
  	return NULL;
  }
  
  static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
  {
  	dst_release(dst);
  	return NULL;
  }
  
  static void dn_dst_link_failure(struct sk_buff *skb)
  {

  }
  
  static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
  {

  	return ((fl1->fld_dst ^ fl2->fld_dst) |
  		(fl1->fld_src ^ fl2->fld_src) |

  		(fl1->mark ^ fl2->mark) |

  		(fl1->fld_scope ^ fl2->fld_scope) |

  		(fl1->oif ^ fl2->oif) |
  		(fl1->iif ^ fl2->iif)) == 0;

  }
  
  static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
  {

  	struct dn_route *rth;
  	struct dn_route __rcu **rthp;

  	unsigned long now = jiffies;
  
  	rthp = &dn_rt_hash_table[hash].chain;
  
  	spin_lock_bh(&dn_rt_hash_table[hash].lock);

  	while ((rth = rcu_dereference_protected(*rthp,
  						lockdep_is_held(&dn_rt_hash_table[hash].lock))) != NULL) {

  		if (compare_keys(&rth->fl, &rt->fl)) {
  			/* Put it first */

  			*rthp = rth->dst.dn_next;
  			rcu_assign_pointer(rth->dst.dn_next,

  					   dn_rt_hash_table[hash].chain);
  			rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);

  			dst_use(&rth->dst, now);

  			spin_unlock_bh(&dn_rt_hash_table[hash].lock);
  
  			dnrt_drop(rt);
  			*rp = rth;
  			return 0;
  		}

  		rthp = &rth->dst.dn_next;

  	}

  	rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain);

  	rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);

  	dst_use(&rt->dst, now);

  	spin_unlock_bh(&dn_rt_hash_table[hash].lock);
  	*rp = rt;
  	return 0;
  }

  static void dn_run_flush(unsigned long dummy)

  {
  	int i;
  	struct dn_route *rt, *next;

  	for (i = 0; i < dn_rt_hash_mask; i++) {

  		spin_lock_bh(&dn_rt_hash_table[i].lock);

  		if ((rt = xchg((struct dn_route **)&dn_rt_hash_table[i].chain, NULL)) == NULL)

  			goto nothing_to_declare;

  		for(; rt; rt = next) {
  			next = rcu_dereference_raw(rt->dst.dn_next);
  			RCU_INIT_POINTER(rt->dst.dn_next, NULL);

  			dst_free((struct dst_entry *)rt);
  		}
  
  nothing_to_declare:
  		spin_unlock_bh(&dn_rt_hash_table[i].lock);
  	}
  }
  
  static DEFINE_SPINLOCK(dn_rt_flush_lock);
  
  void dn_rt_cache_flush(int delay)
  {
  	unsigned long now = jiffies;
  	int user_mode = !in_interrupt();
  
  	if (delay < 0)
  		delay = dn_rt_min_delay;
  
  	spin_lock_bh(&dn_rt_flush_lock);
  
  	if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
  		long tmo = (long)(dn_rt_deadline - now);
  
  		if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
  			tmo = 0;
  
  		if (delay > tmo)
  			delay = tmo;
  	}
  
  	if (delay <= 0) {
  		spin_unlock_bh(&dn_rt_flush_lock);
  		dn_run_flush(0);
  		return;
  	}
  
  	if (dn_rt_deadline == 0)
  		dn_rt_deadline = now + dn_rt_max_delay;
  
  	dn_rt_flush_timer.expires = now + delay;
  	add_timer(&dn_rt_flush_timer);
  	spin_unlock_bh(&dn_rt_flush_lock);
  }
  
  /**
   * dn_return_short - Return a short packet to its sender
   * @skb: The packet to return
   *
   */
  static int dn_return_short(struct sk_buff *skb)
  {
  	struct dn_skb_cb *cb;
  	unsigned char *ptr;

  	__le16 *src;
  	__le16 *dst;

  
  	/* Add back headers */

  	skb_push(skb, skb->data - skb_network_header(skb));

  
  	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
  		return NET_RX_DROP;
  
  	cb = DN_SKB_CB(skb);
  	/* Skip packet length and point to flags */
  	ptr = skb->data + 2;
  	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;

  	dst = (__le16 *)ptr;

  	ptr += 2;

  	src = (__le16 *)ptr;

  	ptr += 2;
  	*ptr = 0; /* Zero hop count */

  	swap(*src, *dst);

  
  	skb->pkt_type = PACKET_OUTGOING;
  	dn_rt_finish_output(skb, NULL, NULL);
  	return NET_RX_SUCCESS;
  }
  
  /**
   * dn_return_long - Return a long packet to its sender
   * @skb: The long format packet to return
   *
   */
  static int dn_return_long(struct sk_buff *skb)
  {
  	struct dn_skb_cb *cb;
  	unsigned char *ptr;
  	unsigned char *src_addr, *dst_addr;
  	unsigned char tmp[ETH_ALEN];
  
  	/* Add back all headers */

  	skb_push(skb, skb->data - skb_network_header(skb));

  
  	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
  		return NET_RX_DROP;
  
  	cb = DN_SKB_CB(skb);
  	/* Ignore packet length and point to flags */
  	ptr = skb->data + 2;
  
  	/* Skip padding */
  	if (*ptr & DN_RT_F_PF) {
  		char padlen = (*ptr & ~DN_RT_F_PF);
  		ptr += padlen;
  	}
  
  	*ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
  	ptr += 2;
  	dst_addr = ptr;
  	ptr += 8;
  	src_addr = ptr;
  	ptr += 6;
  	*ptr = 0; /* Zero hop count */
  
  	/* Swap source and destination */
  	memcpy(tmp, src_addr, ETH_ALEN);
  	memcpy(src_addr, dst_addr, ETH_ALEN);
  	memcpy(dst_addr, tmp, ETH_ALEN);
  
  	skb->pkt_type = PACKET_OUTGOING;
  	dn_rt_finish_output(skb, dst_addr, src_addr);
  	return NET_RX_SUCCESS;
  }
  
  /**
   * dn_route_rx_packet - Try and find a route for an incoming packet
   * @skb: The packet to find a route for
   *
   * Returns: result of input function if route is found, error code otherwise
   */
  static int dn_route_rx_packet(struct sk_buff *skb)
  {

  	struct dn_skb_cb *cb;

  	int err;
  
  	if ((err = dn_route_input(skb)) == 0)
  		return dst_input(skb);

  	cb = DN_SKB_CB(skb);

  	if (decnet_debug_level & 4) {
  		char *devname = skb->dev ? skb->dev->name : "???";

  		printk(KERN_DEBUG
  			"DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d
  ",

  			(int)cb->rt_flags, devname, skb->len,

  			le16_to_cpu(cb->src), le16_to_cpu(cb->dst),

  			err, skb->pkt_type);
  	}
  
  	if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
  		switch(cb->rt_flags & DN_RT_PKT_MSK) {
  			case DN_RT_PKT_SHORT:
  				return dn_return_short(skb);
  			case DN_RT_PKT_LONG:
  				return dn_return_long(skb);
  		}
  	}
  
  	kfree_skb(skb);
  	return NET_RX_DROP;
  }
  
  static int dn_route_rx_long(struct sk_buff *skb)
  {
  	struct dn_skb_cb *cb = DN_SKB_CB(skb);
  	unsigned char *ptr = skb->data;
  
  	if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
  		goto drop_it;
  
  	skb_pull(skb, 20);

  	skb_reset_transport_header(skb);

  	/* Destination info */
  	ptr += 2;

  	cb->dst = dn_eth2dn(ptr);

  	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
  		goto drop_it;
  	ptr += 6;

  	/* Source info */
  	ptr += 2;

  	cb->src = dn_eth2dn(ptr);

  	if (memcmp(ptr, dn_hiord_addr, 4) != 0)
  		goto drop_it;
  	ptr += 6;
  	/* Other junk */
  	ptr++;
  	cb->hops = *ptr++; /* Visit Count */

  	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
  		       dn_route_rx_packet);

  
  drop_it:
  	kfree_skb(skb);
  	return NET_RX_DROP;
  }
  
  
  
  static int dn_route_rx_short(struct sk_buff *skb)
  {
  	struct dn_skb_cb *cb = DN_SKB_CB(skb);
  	unsigned char *ptr = skb->data;
  
  	if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
  		goto drop_it;
  
  	skb_pull(skb, 5);

  	skb_reset_transport_header(skb);

  	cb->dst = *(__le16 *)ptr;

  	ptr += 2;
  	cb->src = *(__le16 *)ptr;
  	ptr += 2;
  	cb->hops = *ptr & 0x3f;

  	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
  		       dn_route_rx_packet);

  
  drop_it:

  	kfree_skb(skb);
  	return NET_RX_DROP;

  }
  
  static int dn_route_discard(struct sk_buff *skb)
  {
  	/*
  	 * I know we drop the packet here, but thats considered success in
  	 * this case
  	 */
  	kfree_skb(skb);
  	return NET_RX_SUCCESS;
  }
  
  static int dn_route_ptp_hello(struct sk_buff *skb)
  {
  	dn_dev_hello(skb);
  	dn_neigh_pointopoint_hello(skb);
  	return NET_RX_SUCCESS;
  }

  int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)

  {
  	struct dn_skb_cb *cb;
  	unsigned char flags = 0;

  	__u16 len = le16_to_cpu(*(__le16 *)skb->data);

  	struct dn_dev *dn = rcu_dereference(dev->dn_ptr);

  	unsigned char padlen = 0;

  	if (!net_eq(dev_net(dev), &init_net))

  		goto dump_it;

  	if (dn == NULL)
  		goto dump_it;
  
  	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
  		goto out;
  
  	if (!pskb_may_pull(skb, 3))
  		goto dump_it;
  
  	skb_pull(skb, 2);
  
  	if (len > skb->len)
  		goto dump_it;
  
  	skb_trim(skb, len);
  
  	flags = *skb->data;
  
  	cb = DN_SKB_CB(skb);
  	cb->stamp = jiffies;
  	cb->iif = dev->ifindex;
  
  	/*
  	 * If we have padding, remove it.
  	 */
  	if (flags & DN_RT_F_PF) {
  		padlen = flags & ~DN_RT_F_PF;
  		if (!pskb_may_pull(skb, padlen + 1))
  			goto dump_it;
  		skb_pull(skb, padlen);
  		flags = *skb->data;
  	}

  	skb_reset_network_header(skb);

  
  	/*
  	 * Weed out future version DECnet
  	 */
  	if (flags & DN_RT_F_VER)
  		goto dump_it;
  
  	cb->rt_flags = flags;
  
  	if (decnet_debug_level & 1)

  		printk(KERN_DEBUG

  			"dn_route_rcv: got 0x%02x from %s [%d %d %d]
  ",

  			(int)flags, (dev) ? dev->name : "???", len, skb->len,

  			padlen);

  	if (flags & DN_RT_PKT_CNTL) {

  		if (unlikely(skb_linearize(skb)))

  			goto dump_it;

  		switch(flags & DN_RT_CNTL_MSK) {
  			case DN_RT_PKT_INIT:

  				dn_dev_init_pkt(skb);
  				break;

  			case DN_RT_PKT_VERI:

  				dn_dev_veri_pkt(skb);
  				break;
  		}
  
  		if (dn->parms.state != DN_DEV_S_RU)
  			goto dump_it;
  
  		switch(flags & DN_RT_CNTL_MSK) {

  			case DN_RT_PKT_HELO:

  				return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
  					       skb, skb->dev, NULL,
  					       dn_route_ptp_hello);

  			case DN_RT_PKT_L1RT:
  			case DN_RT_PKT_L2RT:

  				return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
  					       skb, skb->dev, NULL,
  					       dn_route_discard);

  			case DN_RT_PKT_ERTH:

  				return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
  					       skb, skb->dev, NULL,
  					       dn_neigh_router_hello);

  			case DN_RT_PKT_EEDH:

  				return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
  					       skb, skb->dev, NULL,
  					       dn_neigh_endnode_hello);

  		}
  	} else {

  		if (dn->parms.state != DN_DEV_S_RU)
  			goto dump_it;
  
  		skb_pull(skb, 1); /* Pull flags */

  		switch(flags & DN_RT_PKT_MSK) {
  			case DN_RT_PKT_LONG:
  				return dn_route_rx_long(skb);
  			case DN_RT_PKT_SHORT:
  				return dn_route_rx_short(skb);

  		}

  	}

  
  dump_it:
  	kfree_skb(skb);
  out:
  	return NET_RX_DROP;
  }
  
  static int dn_output(struct sk_buff *skb)
  {

  	struct dst_entry *dst = skb_dst(skb);

  	struct dn_route *rt = (struct dn_route *)dst;
  	struct net_device *dev = dst->dev;
  	struct dn_skb_cb *cb = DN_SKB_CB(skb);
  	struct neighbour *neigh;
  
  	int err = -EINVAL;
  
  	if ((neigh = dst->neighbour) == NULL)
  		goto error;
  
  	skb->dev = dev;
  
  	cb->src = rt->rt_saddr;
  	cb->dst = rt->rt_daddr;
  
  	/*
  	 * Always set the Intra-Ethernet bit on all outgoing packets
  	 * originated on this node. Only valid flag from upper layers
  	 * is return-to-sender-requested. Set hop count to 0 too.
  	 */
  	cb->rt_flags &= ~DN_RT_F_RQR;
  	cb->rt_flags |= DN_RT_F_IE;
  	cb->hops = 0;

  	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
  		       neigh->output);

  
  error:
  	if (net_ratelimit())
  		printk(KERN_DEBUG "dn_output: This should not happen
  ");
  
  	kfree_skb(skb);
  
  	return err;
  }
  
  static int dn_forward(struct sk_buff *skb)
  {
  	struct dn_skb_cb *cb = DN_SKB_CB(skb);

  	struct dst_entry *dst = skb_dst(skb);

  	struct dn_dev *dn_db = rcu_dereference(dst->dev->dn_ptr);

  	struct dn_route *rt;
  	struct neighbour *neigh = dst->neighbour;
  	int header_len;
  #ifdef CONFIG_NETFILTER
  	struct net_device *dev = skb->dev;
  #endif
  
  	if (skb->pkt_type != PACKET_HOST)
  		goto drop;
  
  	/* Ensure that we have enough space for headers */

  	rt = (struct dn_route *)skb_dst(skb);

  	header_len = dn_db->use_long ? 21 : 6;

  	if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+header_len))

  		goto drop;
  
  	/*
  	 * Hop count exceeded.
  	 */
  	if (++cb->hops > 30)
  		goto drop;

  	skb->dev = rt->dst.dev;

  
  	/*
  	 * If packet goes out same interface it came in on, then set
  	 * the Intra-Ethernet bit. This has no effect for short
  	 * packets, so we don't need to test for them here.
  	 */
  	cb->rt_flags &= ~DN_RT_F_IE;
  	if (rt->rt_flags & RTCF_DOREDIRECT)
  		cb->rt_flags |= DN_RT_F_IE;

  	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
  		       neigh->output);

  
  drop:
  	kfree_skb(skb);
  	return NET_RX_DROP;
  }
  
  /*

   * Used to catch bugs. This should never normally get
   * called.
   */
  static int dn_rt_bug(struct sk_buff *skb)
  {
  	if (net_ratelimit()) {
  		struct dn_skb_cb *cb = DN_SKB_CB(skb);
  
  		printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x
  ",

  				le16_to_cpu(cb->src), le16_to_cpu(cb->dst));

  	}
  
  	kfree_skb(skb);

  	return NET_RX_DROP;

  }

  static unsigned int dn_dst_default_advmss(const struct dst_entry *dst)
  {
  	return dn_mss_from_pmtu(dst->dev, dst_mtu(dst));
  }

  static unsigned int dn_dst_default_mtu(const struct dst_entry *dst)
  {
  	return dst->dev->mtu;
  }

  static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
  {
  	struct dn_fib_info *fi = res->fi;

  	struct net_device *dev = rt->dst.dev;

  	unsigned int mss_metric;

  	struct neighbour *n;

  
  	if (fi) {
  		if (DN_FIB_RES_GW(*res) &&
  		    DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
  			rt->rt_gateway = DN_FIB_RES_GW(*res);

  		dst_init_metrics(&rt->dst, fi->fib_metrics, true);

  	}
  	rt->rt_type = res->type;

  	if (dev != NULL && rt->dst.neighbour == NULL) {

  		n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
  		if (IS_ERR(n))
  			return PTR_ERR(n);

  		rt->dst.neighbour = n;

  	}

  	if (dst_metric(&rt->dst, RTAX_MTU) > rt->dst.dev->mtu)

  		dst_metric_set(&rt->dst, RTAX_MTU, rt->dst.dev->mtu);

  	mss_metric = dst_metric_raw(&rt->dst, RTAX_ADVMSS);
  	if (mss_metric) {

  		unsigned int mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->dst));

  		if (mss_metric > mss)

  			dst_metric_set(&rt->dst, RTAX_ADVMSS, mss);
  	}

  	return 0;
  }

  static inline int dn_match_addr(__le16 addr1, __le16 addr2)

  {

  	__u16 tmp = le16_to_cpu(addr1) ^ le16_to_cpu(addr2);

  	int match = 16;
  	while(tmp) {
  		tmp >>= 1;
  		match--;
  	}
  	return match;
  }

  static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)

  {

  	__le16 saddr = 0;

  	struct dn_dev *dn_db;

  	struct dn_ifaddr *ifa;
  	int best_match = 0;
  	int ret;

  	rcu_read_lock();
  	dn_db = rcu_dereference(dev->dn_ptr);
  	for (ifa = rcu_dereference(dn_db->ifa_list);
  	     ifa != NULL;
  	     ifa = rcu_dereference(ifa->ifa_next)) {

  		if (ifa->ifa_scope > scope)
  			continue;
  		if (!daddr) {
  			saddr = ifa->ifa_local;
  			break;
  		}
  		ret = dn_match_addr(daddr, ifa->ifa_local);
  		if (ret > best_match)
  			saddr = ifa->ifa_local;
  		if (best_match == 0)
  			saddr = ifa->ifa_local;
  	}

  	rcu_read_unlock();

  
  	return saddr;
  }

  static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)

  {
  	return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
  }

  static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)

  {

  	__le16 mask = dnet_make_mask(res->prefixlen);

  	return (daddr&~mask)|res->fi->fib_nh->nh_gw;
  }
  
  static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
  {

  	struct flowi fl = { .fld_dst = oldflp->fld_dst,
  			    .fld_src = oldflp->fld_src,
  			    .fld_scope = RT_SCOPE_UNIVERSE,

  			    .mark = oldflp->mark,

  			    .iif = init_net.loopback_dev->ifindex,

  			    .oif = oldflp->oif };
  	struct dn_route *rt = NULL;

  	struct net_device *dev_out = NULL, *dev;

  	struct neighbour *neigh = NULL;
  	unsigned hash;
  	unsigned flags = 0;
  	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
  	int err;
  	int free_res = 0;

  	__le16 gateway = 0;

  
  	if (decnet_debug_level & 16)
  		printk(KERN_DEBUG
  		       "dn_route_output_slow: dst=%04x src=%04x mark=%d"

  		       " iif=%d oif=%d
  ", le16_to_cpu(oldflp->fld_dst),
  		       le16_to_cpu(oldflp->fld_src),

  		       oldflp->mark, init_net.loopback_dev->ifindex, oldflp->oif);

  
  	/* If we have an output interface, verify its a DECnet device */
  	if (oldflp->oif) {

  		dev_out = dev_get_by_index(&init_net, oldflp->oif);

  		err = -ENODEV;
  		if (dev_out && dev_out->dn_ptr == NULL) {
  			dev_put(dev_out);
  			dev_out = NULL;
  		}
  		if (dev_out == NULL)
  			goto out;
  	}
  
  	/* If we have a source address, verify that its a local address */
  	if (oldflp->fld_src) {
  		err = -EADDRNOTAVAIL;
  
  		if (dev_out) {
  			if (dn_dev_islocal(dev_out, oldflp->fld_src))
  				goto source_ok;
  			dev_put(dev_out);
  			goto out;
  		}

  		rcu_read_lock();
  		for_each_netdev_rcu(&init_net, dev) {

  			if (!dev->dn_ptr)

  				continue;

  			if (!dn_dev_islocal(dev, oldflp->fld_src))

  				continue;

  			if ((dev->flags & IFF_LOOPBACK) &&

  			    oldflp->fld_dst &&

  			    !dn_dev_islocal(dev, oldflp->fld_dst))

  				continue;

  
  			dev_out = dev;

  			break;

  		}

  		rcu_read_unlock();

  		if (dev_out == NULL)
  			goto out;
  		dev_hold(dev_out);
  source_ok:
  		;
  	}
  
  	/* No destination? Assume its local */
  	if (!fl.fld_dst) {
  		fl.fld_dst = fl.fld_src;
  
  		err = -EADDRNOTAVAIL;
  		if (dev_out)
  			dev_put(dev_out);

  		dev_out = init_net.loopback_dev;

  		dev_hold(dev_out);
  		if (!fl.fld_dst) {
  			fl.fld_dst =
  			fl.fld_src = dnet_select_source(dev_out, 0,
  						       RT_SCOPE_HOST);
  			if (!fl.fld_dst)
  				goto out;
  		}

  		fl.oif = init_net.loopback_dev->ifindex;

  		res.type = RTN_LOCAL;
  		goto make_route;
  	}
  
  	if (decnet_debug_level & 16)
  		printk(KERN_DEBUG
  		       "dn_route_output_slow: initial checks complete."

  		       " dst=%o4x src=%04x oif=%d try_hard=%d
  ",

  		       le16_to_cpu(fl.fld_dst), le16_to_cpu(fl.fld_src),

  		       fl.oif, try_hard);

  
  	/*
  	 * N.B. If the kernel is compiled without router support then
  	 * dn_fib_lookup() will evaluate to non-zero so this if () block
  	 * will always be executed.
  	 */
  	err = -ESRCH;
  	if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
  		struct dn_dev *dn_db;
  		if (err != -ESRCH)
  			goto out;
  		/*

  		 * Here the fallback is basically the standard algorithm for

  		 * routing in endnodes which is described in the DECnet routing
  		 * docs
  		 *
  		 * If we are not trying hard, look in neighbour cache.
  		 * The result is tested to ensure that if a specific output

  		 * device/source address was requested, then we honour that

  		 * here
  		 */
  		if (!try_hard) {

  			neigh = neigh_lookup_nodev(&dn_neigh_table, &init_net, &fl.fld_dst);

  			if (neigh) {

  				if ((oldflp->oif &&

  				    (neigh->dev->ifindex != oldflp->oif)) ||
  				    (oldflp->fld_src &&
  				    (!dn_dev_islocal(neigh->dev,
  						      oldflp->fld_src)))) {
  					neigh_release(neigh);
  					neigh = NULL;
  				} else {
  					if (dev_out)
  						dev_put(dev_out);
  					if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {

  						dev_out = init_net.loopback_dev;

  						res.type = RTN_LOCAL;
  					} else {
  						dev_out = neigh->dev;
  					}
  					dev_hold(dev_out);
  					goto select_source;
  				}
  			}
  		}
  
  		/* Not there? Perhaps its a local address */
  		if (dev_out == NULL)
  			dev_out = dn_dev_get_default();
  		err = -ENODEV;
  		if (dev_out == NULL)
  			goto out;

  		dn_db = rcu_dereference_raw(dev_out->dn_ptr);

  		/* Possible improvement - check all devices for local addr */
  		if (dn_dev_islocal(dev_out, fl.fld_dst)) {
  			dev_put(dev_out);

  			dev_out = init_net.loopback_dev;

  			dev_hold(dev_out);
  			res.type = RTN_LOCAL;
  			goto select_source;
  		}
  		/* Not local either.... try sending it to the default router */
  		neigh = neigh_clone(dn_db->router);
  		BUG_ON(neigh && neigh->dev != dev_out);
  
  		/* Ok then, we assume its directly connected and move on */
  select_source:
  		if (neigh)
  			gateway = ((struct dn_neigh *)neigh)->addr;
  		if (gateway == 0)
  			gateway = fl.fld_dst;
  		if (fl.fld_src == 0) {
  			fl.fld_src = dnet_select_source(dev_out, gateway,
  							 res.type == RTN_LOCAL ?

  							 RT_SCOPE_HOST :

  							 RT_SCOPE_LINK);
  			if (fl.fld_src == 0 && res.type != RTN_LOCAL)
  				goto e_addr;
  		}
  		fl.oif = dev_out->ifindex;
  		goto make_route;
  	}
  	free_res = 1;
  
  	if (res.type == RTN_NAT)
  		goto e_inval;
  
  	if (res.type == RTN_LOCAL) {
  		if (!fl.fld_src)
  			fl.fld_src = fl.fld_dst;
  		if (dev_out)
  			dev_put(dev_out);

  		dev_out = init_net.loopback_dev;

  		dev_hold(dev_out);
  		fl.oif = dev_out->ifindex;
  		if (res.fi)
  			dn_fib_info_put(res.fi);
  		res.fi = NULL;
  		goto make_route;
  	}
  
  	if (res.fi->fib_nhs > 1 && fl.oif == 0)
  		dn_fib_select_multipath(&fl, &res);

  	/*

  	 * We could add some logic to deal with default routes here and
  	 * get rid of some of the special casing above.
  	 */
  
  	if (!fl.fld_src)
  		fl.fld_src = DN_FIB_RES_PREFSRC(res);

  	if (dev_out)
  		dev_put(dev_out);
  	dev_out = DN_FIB_RES_DEV(res);
  	dev_hold(dev_out);
  	fl.oif = dev_out->ifindex;
  	gateway = DN_FIB_RES_GW(res);
  
  make_route:
  	if (dev_out->flags & IFF_LOOPBACK)
  		flags |= RTCF_LOCAL;

  	rt = dst_alloc(&dn_dst_ops, 0);

  	if (rt == NULL)
  		goto e_nobufs;

  	atomic_set(&rt->dst.__refcnt, 1);
  	rt->dst.flags   = DST_HOST;

  
  	rt->fl.fld_src    = oldflp->fld_src;
  	rt->fl.fld_dst    = oldflp->fld_dst;
  	rt->fl.oif        = oldflp->oif;
  	rt->fl.iif        = 0;

  	rt->fl.mark       = oldflp->mark;

  
  	rt->rt_saddr      = fl.fld_src;
  	rt->rt_daddr      = fl.fld_dst;
  	rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
  	rt->rt_local_src  = fl.fld_src;
  
  	rt->rt_dst_map    = fl.fld_dst;
  	rt->rt_src_map    = fl.fld_src;

  	rt->dst.dev = dev_out;

  	dev_hold(dev_out);

  	rt->dst.neighbour = neigh;

  	neigh = NULL;

  	rt->dst.lastuse = jiffies;
  	rt->dst.output  = dn_output;
  	rt->dst.input   = dn_rt_bug;

  	rt->rt_flags      = flags;
  	if (flags & RTCF_LOCAL)

  		rt->dst.input = dn_nsp_rx;

  
  	err = dn_rt_set_next_hop(rt, &res);
  	if (err)
  		goto e_neighbour;
  
  	hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
  	dn_insert_route(rt, hash, (struct dn_route **)pprt);
  
  done:
  	if (neigh)
  		neigh_release(neigh);
  	if (free_res)
  		dn_fib_res_put(&res);
  	if (dev_out)
  		dev_put(dev_out);
  out:
  	return err;
  
  e_addr:

  	err = -EADDRNOTAVAIL;
  	goto done;

  e_inval:
  	err = -EINVAL;
  	goto done;
  e_nobufs:
  	err = -ENOBUFS;
  	goto done;
  e_neighbour:

  	dst_free(&rt->dst);

  	goto e_nobufs;
  }
  
  
  /*
   * N.B. The flags may be moved into the flowi at some future stage.
   */
  static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
  {
  	unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
  	struct dn_route *rt = NULL;
  
  	if (!(flags & MSG_TRYHARD)) {
  		rcu_read_lock_bh();

  		for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt;

  			rt = rcu_dereference_bh(rt->dst.dn_next)) {

  			if ((flp->fld_dst == rt->fl.fld_dst) &&
  			    (flp->fld_src == rt->fl.fld_src) &&

  			    (flp->mark == rt->fl.mark) &&

  			    dn_is_output_route(rt) &&

  			    (rt->fl.oif == flp->oif)) {

  				dst_use(&rt->dst, jiffies);

  				rcu_read_unlock_bh();

  				*pprt = &rt->dst;

  				return 0;
  			}
  		}
  		rcu_read_unlock_bh();
  	}
  
  	return dn_route_output_slow(pprt, flp, flags);
  }
  
  static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
  {
  	int err;
  
  	err = __dn_route_output_key(pprt, flp, flags);
  	if (err == 0 && flp->proto) {

  		err = xfrm_lookup(&init_net, pprt, flp, NULL, 0);

  	}
  	return err;
  }
  
  int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
  {
  	int err;
  
  	err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
  	if (err == 0 && fl->proto) {

  		err = xfrm_lookup(&init_net, pprt, fl, sk,
  				 (flags & MSG_DONTWAIT) ? 0 : XFRM_LOOKUP_WAIT);

  	}
  	return err;
  }
  
  static int dn_route_input_slow(struct sk_buff *skb)
  {
  	struct dn_route *rt = NULL;
  	struct dn_skb_cb *cb = DN_SKB_CB(skb);
  	struct net_device *in_dev = skb->dev;
  	struct net_device *out_dev = NULL;
  	struct dn_dev *dn_db;
  	struct neighbour *neigh = NULL;
  	unsigned hash;
  	int flags = 0;

  	__le16 gateway = 0;
  	__le16 local_src = 0;

  	struct flowi fl = { .fld_dst = cb->dst,
  			    .fld_src = cb->src,
  			    .fld_scope = RT_SCOPE_UNIVERSE,

  			    .mark = skb->mark,

  			    .iif = skb->dev->ifindex };
  	struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
  	int err = -EINVAL;
  	int free_res = 0;
  
  	dev_hold(in_dev);

  	if ((dn_db = rcu_dereference(in_dev->dn_ptr)) == NULL)

  		goto out;
  
  	/* Zero source addresses are not allowed */
  	if (fl.fld_src == 0)
  		goto out;
  
  	/*
  	 * In this case we've just received a packet from a source
  	 * outside ourselves pretending to come from us. We don't
  	 * allow it any further to prevent routing loops, spoofing and
  	 * other nasties. Loopback packets already have the dst attached
  	 * so this only affects packets which have originated elsewhere.
  	 */
  	err  = -ENOTUNIQ;
  	if (dn_dev_islocal(in_dev, cb->src))
  		goto out;
  
  	err = dn_fib_lookup(&fl, &res);
  	if (err) {
  		if (err != -ESRCH)
  			goto out;
  		/*
  		 * Is the destination us ?
  		 */
  		if (!dn_dev_islocal(in_dev, cb->dst))
  			goto e_inval;
  
  		res.type = RTN_LOCAL;

  	} else {

  		__le16 src_map = fl.fld_src;

  		free_res = 1;
  
  		out_dev = DN_FIB_RES_DEV(res);
  		if (out_dev == NULL) {
  			if (net_ratelimit())
  				printk(KERN_CRIT "Bug in dn_route_input_slow() "
  						 "No output device
  ");
  			goto e_inval;
  		}
  		dev_hold(out_dev);
  
  		if (res.r)

  			src_map = fl.fld_src; /* no NAT support for now */

  
  		gateway = DN_FIB_RES_GW(res);
  		if (res.type == RTN_NAT) {
  			fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
  			dn_fib_res_put(&res);
  			free_res = 0;
  			if (dn_fib_lookup(&fl, &res))
  				goto e_inval;
  			free_res = 1;
  			if (res.type != RTN_UNICAST)
  				goto e_inval;
  			flags |= RTCF_DNAT;
  			gateway = fl.fld_dst;
  		}
  		fl.fld_src = src_map;
  	}
  
  	switch(res.type) {
  	case RTN_UNICAST:
  		/*
  		 * Forwarding check here, we only check for forwarding
  		 * being turned off, if you want to only forward intra
  		 * area, its up to you to set the routing tables up
  		 * correctly.
  		 */
  		if (dn_db->parms.forwarding == 0)
  			goto e_inval;
  
  		if (res.fi->fib_nhs > 1 && fl.oif == 0)
  			dn_fib_select_multipath(&fl, &res);

  		/*

  		 * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
  		 * flag as a hint to set the intra-ethernet bit when
  		 * forwarding. If we've got NAT in operation, we don't do
  		 * this optimisation.
  		 */
  		if (out_dev == in_dev && !(flags & RTCF_NAT))
  			flags |= RTCF_DOREDIRECT;
  
  		local_src = DN_FIB_RES_PREFSRC(res);
  
  	case RTN_BLACKHOLE:
  	case RTN_UNREACHABLE:
  		break;
  	case RTN_LOCAL:
  		flags |= RTCF_LOCAL;
  		fl.fld_src = cb->dst;
  		fl.fld_dst = cb->src;
  
  		/* Routing tables gave us a gateway */
  		if (gateway)
  			goto make_route;
  
  		/* Packet was intra-ethernet, so we know its on-link */

  		if (cb->rt_flags & DN_RT_F_IE) {

  			gateway = cb->src;
  			flags |= RTCF_DIRECTSRC;
  			goto make_route;
  		}
  
  		/* Use the default router if there is one */
  		neigh = neigh_clone(dn_db->router);
  		if (neigh) {
  			gateway = ((struct dn_neigh *)neigh)->addr;
  			goto make_route;
  		}
  
  		/* Close eyes and pray */
  		gateway = cb->src;
  		flags |= RTCF_DIRECTSRC;
  		goto make_route;
  	default:
  		goto e_inval;
  	}
  
  make_route:

  	rt = dst_alloc(&dn_dst_ops, 0);

  	if (rt == NULL)
  		goto e_nobufs;
  
  	rt->rt_saddr      = fl.fld_src;
  	rt->rt_daddr      = fl.fld_dst;
  	rt->rt_gateway    = fl.fld_dst;
  	if (gateway)
  		rt->rt_gateway = gateway;
  	rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
  
  	rt->rt_dst_map    = fl.fld_dst;
  	rt->rt_src_map    = fl.fld_src;
  
  	rt->fl.fld_src    = cb->src;
  	rt->fl.fld_dst    = cb->dst;
  	rt->fl.oif        = 0;
  	rt->fl.iif        = in_dev->ifindex;

  	rt->fl.mark       = fl.mark;

  	rt->dst.flags = DST_HOST;
  	rt->dst.neighbour = neigh;
  	rt->dst.dev = out_dev;
  	rt->dst.lastuse = jiffies;
  	rt->dst.output = dn_rt_bug;

  	switch(res.type) {
  		case RTN_UNICAST:

  			rt->dst.input = dn_forward;

  			break;
  		case RTN_LOCAL:

  			rt->dst.output = dn_output;
  			rt->dst.input = dn_nsp_rx;
  			rt->dst.dev = in_dev;

  			flags |= RTCF_LOCAL;
  			break;
  		default:
  		case RTN_UNREACHABLE:
  		case RTN_BLACKHOLE:

  			rt->dst.input = dst_discard;

  	}
  	rt->rt_flags = flags;

  	if (rt->dst.dev)
  		dev_hold(rt->dst.dev);

  
  	err = dn_rt_set_next_hop(rt, &res);
  	if (err)
  		goto e_neighbour;
  
  	hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);

  	dn_insert_route(rt, hash, &rt);

  	skb_dst_set(skb, &rt->dst);

  
  done:
  	if (neigh)
  		neigh_release(neigh);
  	if (free_res)
  		dn_fib_res_put(&res);
  	dev_put(in_dev);
  	if (out_dev)
  		dev_put(out_dev);
  out:
  	return err;
  
  e_inval:
  	err = -EINVAL;
  	goto done;
  
  e_nobufs:
  	err = -ENOBUFS;
  	goto done;
  
  e_neighbour:

  	dst_free(&rt->dst);

  	goto done;
  }

  static int dn_route_input(struct sk_buff *skb)

  {
  	struct dn_route *rt;
  	struct dn_skb_cb *cb = DN_SKB_CB(skb);
  	unsigned hash = dn_hash(cb->src, cb->dst);

  	if (skb_dst(skb))

  		return 0;
  
  	rcu_read_lock();
  	for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;

  	    rt = rcu_dereference(rt->dst.dn_next)) {

  		if ((rt->fl.fld_src == cb->src) &&

  		    (rt->fl.fld_dst == cb->dst) &&

  		    (rt->fl.oif == 0) &&

  		    (rt->fl.mark == skb->mark) &&

  		    (rt->fl.iif == cb->iif)) {

  			dst_use(&rt->dst, jiffies);

  			rcu_read_unlock();

  			skb_dst_set(skb, (struct dst_entry *)rt);

  			return 0;
  		}
  	}
  	rcu_read_unlock();
  
  	return dn_route_input_slow(skb);
  }

  static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
  			   int event, int nowait, unsigned int flags)

  {

  	struct dn_route *rt = (struct dn_route *)skb_dst(skb);

  	struct rtmsg *r;
  	struct nlmsghdr *nlh;

  	unsigned char *b = skb_tail_pointer(skb);

  	long expires;

  	nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);

  	r = NLMSG_DATA(nlh);

  	r->rtm_family = AF_DECnet;
  	r->rtm_dst_len = 16;
  	r->rtm_src_len = 0;
  	r->rtm_tos = 0;
  	r->rtm_table = RT_TABLE_MAIN;

  	RTA_PUT_U32(skb, RTA_TABLE, RT_TABLE_MAIN);

  	r->rtm_type = rt->rt_type;
  	r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
  	r->rtm_scope = RT_SCOPE_UNIVERSE;
  	r->rtm_protocol = RTPROT_UNSPEC;
  	if (rt->rt_flags & RTCF_NOTIFY)
  		r->rtm_flags |= RTM_F_NOTIFY;
  	RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
  	if (rt->fl.fld_src) {
  		r->rtm_src_len = 16;
  		RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
  	}

  	if (rt->dst.dev)
  		RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->dst.dev->ifindex);

  	/*
  	 * Note to self - change this if input routes reverse direction when
  	 * they deal only with inputs and not with replies like they do
  	 * currently.
  	 */
  	RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
  	if (rt->rt_daddr != rt->rt_gateway)
  		RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);

  	if (rtnetlink_put_metrics(skb, dst_metrics_ptr(&rt->dst)) < 0)

  		goto rtattr_failure;

  	expires = rt->dst.expires ? rt->dst.expires - jiffies : 0;
  	if (rtnl_put_cacheinfo(skb, &rt->dst, 0, 0, 0, expires,
  			       rt->dst.error) < 0)

  		goto rtattr_failure;

  	if (dn_is_input_route(rt))

  		RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);

  	nlh->nlmsg_len = skb_tail_pointer(skb) - b;

  	return skb->len;
  
  nlmsg_failure:
  rtattr_failure:

  	nlmsg_trim(skb, b);

  	return -1;

  }
  
  /*
   * This is called by both endnodes and routers now.
   */

  static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)

  {

  	struct net *net = sock_net(in_skb->sk);

  	struct rtattr **rta = arg;
  	struct rtmsg *rtm = NLMSG_DATA(nlh);
  	struct dn_route *rt = NULL;
  	struct dn_skb_cb *cb;
  	int err;
  	struct sk_buff *skb;
  	struct flowi fl;

  	if (!net_eq(net, &init_net))

  		return -EINVAL;

  	memset(&fl, 0, sizeof(fl));
  	fl.proto = DNPROTO_NSP;
  
  	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
  	if (skb == NULL)
  		return -ENOBUFS;

  	skb_reset_mac_header(skb);

  	cb = DN_SKB_CB(skb);
  
  	if (rta[RTA_SRC-1])
  		memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
  	if (rta[RTA_DST-1])
  		memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
  	if (rta[RTA_IIF-1])
  		memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
  
  	if (fl.iif) {
  		struct net_device *dev;

  		if ((dev = dev_get_by_index(&init_net, fl.iif)) == NULL) {

  			kfree_skb(skb);
  			return -ENODEV;
  		}
  		if (!dev->dn_ptr) {
  			dev_put(dev);
  			kfree_skb(skb);
  			return -ENODEV;
  		}

  		skb->protocol = htons(ETH_P_DNA_RT);

  		skb->dev = dev;
  		cb->src = fl.fld_src;
  		cb->dst = fl.fld_dst;
  		local_bh_disable();
  		err = dn_route_input(skb);
  		local_bh_enable();
  		memset(cb, 0, sizeof(struct dn_skb_cb));

  		rt = (struct dn_route *)skb_dst(skb);

  		if (!err && -rt->dst.error)
  			err = rt->dst.error;

  	} else {
  		int oif = 0;
  		if (rta[RTA_OIF - 1])
  			memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
  		fl.oif = oif;
  		err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
  	}
  
  	if (skb->dev)
  		dev_put(skb->dev);
  	skb->dev = NULL;
  	if (err)
  		goto out_free;

  	skb_dst_set(skb, &rt->dst);

  	if (rtm->rtm_flags & RTM_F_NOTIFY)
  		rt->rt_flags |= RTCF_NOTIFY;

  	err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);

  
  	if (err == 0)
  		goto out_free;
  	if (err < 0) {
  		err = -EMSGSIZE;
  		goto out_free;
  	}

  	return rtnl_unicast(skb, &init_net, NETLINK_CB(in_skb).pid);

  
  out_free:
  	kfree_skb(skb);
  	return err;
  }
  
  /*
   * For routers, this is called from dn_fib_dump, but for endnodes its
   * called directly from the rtnetlink dispatch table.
   */
  int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
  {

  	struct net *net = sock_net(skb->sk);

  	struct dn_route *rt;
  	int h, s_h;
  	int idx, s_idx;

  	if (!net_eq(net, &init_net))

  		return 0;

  	if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
  		return -EINVAL;
  	if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
  		return 0;
  
  	s_h = cb->args[0];
  	s_idx = idx = cb->args[1];
  	for(h = 0; h <= dn_rt_hash_mask; h++) {
  		if (h < s_h)
  			continue;
  		if (h > s_h)
  			s_idx = 0;
  		rcu_read_lock_bh();

  		for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0;

  			rt;

  			rt = rcu_dereference_bh(rt->dst.dn_next), idx++) {

  			if (idx < s_idx)
  				continue;

  			skb_dst_set(skb, dst_clone(&rt->dst));

  			if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,

  					cb->nlh->nlmsg_seq, RTM_NEWROUTE,

  					1, NLM_F_MULTI) <= 0) {

  				skb_dst_drop(skb);

  				rcu_read_unlock_bh();
  				goto done;
  			}

  			skb_dst_drop(skb);

  		}
  		rcu_read_unlock_bh();
  	}
  
  done:
  	cb->args[0] = h;
  	cb->args[1] = idx;
  	return skb->len;
  }
  
  #ifdef CONFIG_PROC_FS
  struct dn_rt_cache_iter_state {
  	int bucket;
  };
  
  static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
  {
  	struct dn_route *rt = NULL;
  	struct dn_rt_cache_iter_state *s = seq->private;
  
  	for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
  		rcu_read_lock_bh();

  		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);

  		if (rt)
  			break;
  		rcu_read_unlock_bh();
  	}

  	return rt;

  }
  
  static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
  {

  	struct dn_rt_cache_iter_state *s = seq->private;

  	rt = rcu_dereference_bh(rt->dst.dn_next);
  	while (!rt) {

  		rcu_read_unlock_bh();
  		if (--s->bucket < 0)
  			break;
  		rcu_read_lock_bh();

  		rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain);

  	}

  	return rt;

  }
  
  static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
  {
  	struct dn_route *rt = dn_rt_cache_get_first(seq);
  
  	if (rt) {
  		while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
  			--*pos;
  	}
  	return *pos ? NULL : rt;
  }
  
  static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct dn_route *rt = dn_rt_cache_get_next(seq, v);
  	++*pos;
  	return rt;
  }
  
  static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
  {
  	if (v)
  		rcu_read_unlock_bh();
  }
  
  static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
  {
  	struct dn_route *rt = v;
  	char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
  
  	seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d
  ",

  			rt->dst.dev ? rt->dst.dev->name : "*",

  			dn_addr2asc(le16_to_cpu(rt->rt_daddr), buf1),
  			dn_addr2asc(le16_to_cpu(rt->rt_saddr), buf2),

  			atomic_read(&rt->dst.__refcnt),
  			rt->dst.__use,
  			(int) dst_metric(&rt->dst, RTAX_RTT));

  	return 0;

  }

  static const struct seq_operations dn_rt_cache_seq_ops = {

  	.start	= dn_rt_cache_seq_start,
  	.next	= dn_rt_cache_seq_next,
  	.stop	= dn_rt_cache_seq_stop,
  	.show	= dn_rt_cache_seq_show,
  };
  
  static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
  {

  	return seq_open_private(file, &dn_rt_cache_seq_ops,
  			sizeof(struct dn_rt_cache_iter_state));

  }

  static const struct file_operations dn_rt_cache_seq_fops = {

  	.owner	 = THIS_MODULE,
  	.open	 = dn_rt_cache_seq_open,
  	.read	 = seq_read,
  	.llseek	 = seq_lseek,
  	.release = seq_release_private,
  };
  
  #endif /* CONFIG_PROC_FS */
  
  void __init dn_route_init(void)
  {
  	int i, goal, order;

  	dn_dst_ops.kmem_cachep =
  		kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0,

  				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);

  	dst_entries_init(&dn_dst_ops);

  	setup_timer(&dn_route_timer, dn_dst_check_expire, 0);

  	dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
  	add_timer(&dn_route_timer);

  	goal = totalram_pages >> (26 - PAGE_SHIFT);

  
  	for(order = 0; (1UL << order) < goal; order++)
  		/* NOTHING */;

  	/*
  	 * Only want 1024 entries max, since the table is very, very unlikely
  	 * to be larger than that.
  	 */
  	while(order && ((((1UL << order) * PAGE_SIZE) /
  				sizeof(struct dn_rt_hash_bucket)) >= 2048))
  		order--;
  
  	do {
  		dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
  			sizeof(struct dn_rt_hash_bucket);
  		while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
  			dn_rt_hash_mask--;
  		dn_rt_hash_table = (struct dn_rt_hash_bucket *)
  			__get_free_pages(GFP_ATOMIC, order);
  	} while (dn_rt_hash_table == NULL && --order > 0);

  
  	if (!dn_rt_hash_table)

  		panic("Failed to allocate DECnet route cache hash table
  ");

  	printk(KERN_INFO
  		"DECnet: Routing cache hash table of %u buckets, %ldKbytes
  ",
  		dn_rt_hash_mask,

  		(long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
  
  	dn_rt_hash_mask--;

  	for(i = 0; i <= dn_rt_hash_mask; i++) {
  		spin_lock_init(&dn_rt_hash_table[i].lock);
  		dn_rt_hash_table[i].chain = NULL;
  	}

  	dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);

  	proc_net_fops_create(&init_net, "decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);

  
  #ifdef CONFIG_DECNET_ROUTER
  	rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute, dn_fib_dump);
  #else
  	rtnl_register(PF_DECnet, RTM_GETROUTE, dn_cache_getroute,
  		      dn_cache_dump);
  #endif

  }
  
  void __exit dn_route_cleanup(void)
  {
  	del_timer(&dn_route_timer);
  	dn_run_flush(0);

  	proc_net_remove(&init_net, "decnet_cache");

  	dst_entries_destroy(&dn_dst_ops);

  }