patch-2.3.4 linux/net/decnet/dn_route.c

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diff -u --recursive --new-file v2.3.3/linux/net/decnet/dn_route.c linux/net/decnet/dn_route.c
@@ -0,0 +1,1028 @@
+
+/*
+ * 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.
+ */
+
+/******************************************************************************
+    (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/config.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/inet.h>
+#include <linux/route.h>
+#include <net/sock.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <linux/firewall.h>
+#include <linux/rtnetlink.h>
+#include <linux/string.h>
+#include <asm/errno.h>
+#include <net/neighbour.h>
+#include <net/dst.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>
+#include <net/dn_raw.h>
+
+extern struct neigh_table dn_neigh_table;
+
+#define DN_HASHBUCKETS 16
+
+static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
+
+static int dn_dst_gc(void);
+static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
+static struct dst_entry *dn_dst_reroute(struct dst_entry *, struct sk_buff *skb);
+static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
+static void dn_dst_link_failure(struct sk_buff *);
+static int dn_route_input(struct sk_buff *);
+
+static struct dn_route *dn_route_cache[DN_HASHBUCKETS];
+static struct timer_list dn_route_timer = { NULL, NULL, 0, 0L, NULL };
+int decnet_dst_gc_interval = 2;
+
+static struct dst_ops dn_dst_ops = {
+	PF_DECnet,
+	__constant_htons(ETH_P_DNA_RT),
+	128,
+	dn_dst_gc,
+	dn_dst_check,
+	dn_dst_reroute,
+	NULL,
+	dn_dst_negative_advice,
+	dn_dst_link_failure,
+	ATOMIC_INIT(0)
+};
+
+static __inline__ unsigned dn_hash(unsigned short dest)
+{
+	unsigned short tmp = (dest&0xff) ^ (dest>>8);
+	return (tmp&0x0f) ^ (tmp>>4);
+}
+
+static void dn_dst_check_expire(unsigned long dummy)
+{
+	int i;
+	struct dn_route *rt, **rtp;
+	unsigned long now = jiffies;
+	unsigned long expire = 120 * HZ;
+
+	for(i = 0; i < DN_HASHBUCKETS; i++) {
+		rtp = &dn_route_cache[i];
+		for(;(rt=*rtp); rtp = &rt->u.rt_next) {
+			if (atomic_read(&rt->u.dst.use) ||
+					(now - rt->u.dst.lastuse) < expire)
+				continue;
+			*rtp = rt->u.rt_next;
+			rt->u.rt_next = NULL;
+			dst_free(&rt->u.dst);
+		}
+
+		if ((jiffies - now) > 0)
+			break;
+	}
+
+	dn_route_timer.expires = now + decnet_dst_gc_interval * HZ;
+	add_timer(&dn_route_timer);
+}
+
+static int dn_dst_gc(void)
+{
+	struct dn_route *rt, **rtp;
+	int i;
+	unsigned long now = jiffies;
+	unsigned long expire = 10 * HZ;
+
+	start_bh_atomic();
+	for(i = 0; i < DN_HASHBUCKETS; i++) {
+		rtp = &dn_route_cache[i];
+		for(; (rt=*rtp); rtp = &rt->u.rt_next) {
+			if (atomic_read(&rt->u.dst.use) ||
+					(now - rt->u.dst.lastuse) < expire)
+				continue;
+			*rtp = rt->u.rt_next;
+			rt->u.rt_next = NULL;
+			dst_free(&rt->u.dst);
+			break;
+		}
+	}
+	end_bh_atomic();
+
+	return 0;
+}
+
+static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
+{
+	dst_release(dst);
+	return NULL;
+}
+
+static struct dst_entry *dn_dst_reroute(struct dst_entry *dst,
+					struct sk_buff *skb)
+{
+	return NULL;
+}
+
+/*
+ * This is called through sendmsg() when you specify MSG_TRYHARD
+ * and there is already a route in cache.
+ */
+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)
+{
+	return;
+}
+
+static void dn_insert_route(struct dn_route *rt)
+{
+	unsigned hash = dn_hash(rt->rt_daddr);
+	unsigned long now = jiffies;
+
+	start_bh_atomic();
+
+	rt->u.rt_next = dn_route_cache[hash];
+	dn_route_cache[hash] = rt;
+	
+	atomic_inc(&rt->u.dst.refcnt);
+	atomic_inc(&rt->u.dst.use);
+	rt->u.dst.lastuse = now;
+
+	end_bh_atomic();
+}
+
+#if defined(CONFIG_DECNET_MODULE)
+static void dn_run_flush(unsigned long dummy)
+{
+	int i;
+	struct dn_route *rt, *next;
+
+	for(i = 0; i < DN_HASHBUCKETS; i++) {
+		if ((rt = xchg(&dn_route_cache[i], NULL)) == NULL)
+			continue;
+
+		for(; rt; rt=next) {
+			next = rt->u.rt_next;
+			rt->u.rt_next = NULL;
+			dst_free((struct dst_entry *)rt);
+		}
+	}
+}
+#endif /* CONFIG_DECNET_MODULE */
+
+static int dn_route_rx_long(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	unsigned char *ptr = skb->data;
+
+	if (skb->len < 21) /* 20 for long header, 1 for shortest nsp */
+		goto drop_it;
+
+	skb_pull(skb, 20);
+	skb->h.raw = skb->data;
+
+        /* Destination info */
+        ptr += 2;
+	cb->dst = dn_htons(dn_eth2dn(ptr));
+        if (memcmp(ptr, dn_hiord_addr, 4) != 0)
+                goto drop_it;
+        ptr += 6;
+
+
+        /* Source info */
+        ptr += 2;
+	cb->src = dn_htons(dn_eth2dn(ptr));
+        if (memcmp(ptr, dn_hiord_addr, 4) != 0)
+                goto drop_it;
+        ptr += 6;
+        /* Other junk */
+        ptr++;
+        cb->hops = *ptr++; /* Visit Count */
+
+	if (dn_route_input(skb) == 0) {
+
+#ifdef CONFIG_DECNET_FW
+		struct neighbour *neigh = skb->dst->neighbour;
+
+		switch(call_in_firewall(PF_DECnet, skb->dev, NULL, NULL, &skb)) {
+			case FW_REJECT:
+				neigh->ops->error_report(neigh, skb);
+				return 0;
+			case FW_BLOCK:
+			default:
+				goto drop_it;
+			case FW_ACCEPT:
+		}
+#endif /* CONFIG_DECNET_FW */
+
+		return skb->dst->input(skb);
+	}
+
+drop_it:
+	kfree_skb(skb);
+	return 0;
+}
+
+
+
+static int dn_route_rx_short(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	unsigned char *ptr = skb->data;
+
+	if (skb->len < 6) /* 5 for short header + 1 for shortest nsp */
+		goto drop_it;
+
+	skb_pull(skb, 5);
+	skb->h.raw = skb->data;
+
+	cb->dst = *(dn_address *)ptr;
+        ptr += 2;
+        cb->src = *(dn_address *)ptr;
+        ptr += 2;
+        cb->hops = *ptr & 0x3f;
+
+        if (dn_route_input(skb) == 0) {
+
+#ifdef CONFIG_DECNET_FW
+		struct neighbour *neigh = skb->dst->neighbour;
+
+                switch(call_in_firewall(PF_DECnet, skb->dev, NULL, NULL, &skb)) {
+			case FW_REJECT:
+				neigh->ops->error_report(neigh, skb);
+				return 0;
+			case FW_BLOCK:
+			default:
+				goto drop_it;
+
+                        case FW_ACCEPT:
+		}
+#endif /* CONFIG_DECNET_FW */
+
+		return skb->dst->input(skb);
+        }
+
+drop_it:
+        kfree_skb(skb);
+        return 0;
+}
+
+int dn_route_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *pt)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	unsigned char flags = 0;
+	int padlen = 0;
+	__u16 len = dn_ntohs(*(__u16 *)skb->data);
+	struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
+
+	if (dn == NULL)
+		goto dump_it;
+
+	cb->stamp = jiffies;
+	cb->iif = dev->ifindex;
+
+	skb_pull(skb, 2);
+
+	if (len > skb->len)
+		goto dump_it;
+
+	skb_trim(skb, len);
+
+	flags = *skb->data;
+
+	/*
+	 * If we have padding, remove it.
+	 */
+	if (flags & DN_RT_F_PF) {
+		padlen = flags & ~DN_RT_F_PF;
+		skb_pull(skb, padlen);
+		flags = *skb->data;
+	}
+
+	skb->nh.raw = skb->data;
+
+	/*
+	 * Weed out future version DECnet
+	 */
+	if (flags & DN_RT_F_VER)
+		goto dump_it;
+
+	cb->rt_flags = flags;
+
+	if (dn->parms.setsrc)
+		dn->parms.setsrc(skb);
+
+	/* printk(KERN_DEBUG "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n", (int)flags,
+				(dev) ? dev->name : "???", len, skb->len, padlen);  */
+
+#ifdef CONFIG_DECNET_RAW
+	dn_raw_rx_routing(skb);
+#endif /* CONFIG_DECNET_RAW */
+
+        if (flags & DN_RT_PKT_CNTL) {
+                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:
+				dn_dev_hello(skb);
+				dn_neigh_pointopoint_hello(skb);
+				return 0;
+
+                	case DN_RT_PKT_L1RT:
+                	case DN_RT_PKT_L2RT:
+#ifdef CONFIG_DECNET_ROUTER
+				return dn_fib_rt_message(skb);
+#else
+                      		break;
+#endif /* CONFIG_DECNET_ROUTER */
+                	case DN_RT_PKT_ERTH:
+				dn_neigh_router_hello(skb);
+                        	return 0;
+
+                	case DN_RT_PKT_EEDH:
+				dn_neigh_endnode_hello(skb);
+                        	return 0;
+                }
+        } 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:
+	if (net_ratelimit())
+		printk(KERN_DEBUG "dn_route_rcv: Dumping packet\n");
+	kfree_skb(skb);
+	return 0;
+}
+
+
+void dn_send_skb(struct sk_buff *skb)
+{
+	struct sock *sk = skb->sk;
+	struct dn_scp *scp = &sk->protinfo.dn;
+
+	if (sk == NULL) {
+		dev_queue_xmit(skb);
+		return ;
+	}
+
+	skb->h.raw = skb->data;
+
+	scp->stamp = jiffies; /* Record time packet was sent */
+
+	/* printk(KERN_DEBUG "dn_send_skb\n"); */
+
+	if (sk->dst_cache && sk->dst_cache->obsolete) {
+		dst_release(sk->dst_cache);
+		sk->dst_cache = NULL;
+	}
+
+	if (sk->dst_cache == NULL) {
+		if (dn_route_output(sk) != 0) {
+			kfree_skb(skb);
+			sk->err = EHOSTUNREACH;
+			if (!sk->dead)
+				sk->state_change(sk);
+			return;
+		}
+	}
+
+	skb->dst = dst_clone(sk->dst_cache);
+
+	sk->dst_cache->output(skb);
+}
+
+
+static int dn_output(struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb->dst;
+	struct dn_route *rt = (struct dn_route *)dst;
+	struct device *dev = dst->dev;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	int err = -EINVAL;
+
+	if (!dst->neighbour)
+		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;
+
+	/*
+	 * Filter through the outgoing firewall
+	 */
+#ifdef CONFIG_DECNET_FW
+        switch(call_out_firewall(PF_DECnet, dst->dev, NULL, NULL, &skb)) {
+                case FW_REJECT:
+			err = -EPERM;
+			goto drop;
+                case FW_BLOCK:
+                default:
+                        err = 0;
+                        goto drop;
+                case FW_ACCEPT:
+        }
+#endif /* CONFIG_DECNET_FW */
+
+	return dst->neighbour->output(skb);
+
+error:
+	if (net_ratelimit())
+		printk(KERN_DEBUG "dn_output: This should not happen\n");
+
+#ifdef CONFIG_DECNET_FW
+drop:
+#endif
+	kfree_skb(skb);
+
+	return err;
+}
+
+#ifdef CONFIG_DECNET_ROUTER
+static int dn_l2_forward(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct dst_entry *dst = skb->dst;
+	int err = -EINVAL;
+
+	if (!dst->neighbour)
+		goto error;
+
+	/*
+	 * Hop count exceeded.
+	 */
+	err = 0;
+	if (++cb->hops > 30)
+		goto drop;
+
+	/*
+	 * Forwarding firewall
+	 */
+#ifdef CONFIG_DECNET_FW
+	switch(call_fw_firewall(PF_DECnet, dst->dev, NULL, NULL, &skb)) {
+		case FW_REJECT:
+			dst->neighbour->ops->error_report(dst->neighbour, skb);
+			return -EPERM;
+		case FW_BLOCK:
+		default:
+			goto drop;
+		case FW_ACCEPT:
+	}
+#endif /* CONFIG_DECNET_FW */
+
+	skb->dev = 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.
+	 */
+	if (cb->iif == dst->dev->ifindex)
+		cb->rt_flags |= DN_RT_F_IE;
+	else
+		cb->rt_flags &= ~DN_RT_F_IE;
+
+#ifdef CONFIG_DECNET_FW
+	switch(call_out_firewall(PF_DECnet, dst->dev, NULL, NULL, &skb)) {
+		case FW_REJECT:
+			dst->neighbour->ops->error_report(dst->neighbour, skb);
+			return -EPERM;
+		case FW_BLOCK:
+		default:
+			goto drop;
+		case FW_ACCEPT:
+	}
+#endif /* CONFIG_DECNET_FW */
+
+	return dst->neighbour->output(skb);
+
+
+error:
+	if (net_ratelimit())
+		printk(KERN_DEBUG "dn_forward: This should not happen\n");
+drop:
+	kfree_skb(skb);
+
+	return err;
+}
+
+/*
+ * Simple frontend to the l2 routing function which filters
+ * traffic not in our area when we should only do l1
+ * routing.
+ */
+static int dn_l1_forward(struct sk_buff *skb)
+{
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+
+	if ((dn_ntohs(cb->dst ^ decnet_address) & 0xfc00) == 0)
+		return dn_l2_forward(skb);
+
+	kfree_skb(skb);
+	return 0;
+}
+#endif
+
+/*
+ * Drop packet. This is used for endnodes and for
+ * when we should not be forwarding packets from
+ * this dest.
+ */
+static int dn_blackhole(struct sk_buff *skb)
+{
+	kfree_skb(skb);
+	return 0;
+}
+
+/*
+ * 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 = (struct dn_skb_cb *)skb->cb;
+
+		printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
+				cb->src, cb->dst);
+	}
+
+	kfree_skb(skb);
+
+	return -EINVAL;
+}
+
+static int dn_route_output_slow(struct sock *sk)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	dn_address dest = dn_saddr2dn(&scp->peer);
+	struct dn_route *rt = NULL;
+	struct device *dev  = decnet_default_device;
+	struct neighbour *neigh = NULL;
+	struct dn_dev *dn_db;
+	unsigned char addr[6];
+
+#ifdef CONFIG_DECNET_ROUTER
+	if ((decnet_node_type == DN_RT_INFO_L1RT) || (decnet_node_type == DN_RT_INFO_L2RT)) {
+#if 0
+		struct dn_fib_ent *fe = dn_fib_lookup(dest, decnet_address);
+
+		if (fe != NULL) {
+			neigh = neigh_clone(fe->neigh);
+			dn_fib_release(fe);
+			goto got_route;
+		}
+#endif
+	}
+#endif 
+
+	dn_dn2eth(addr, dest);
+
+	/* Look in On-Ethernet cache first */
+	if ((neigh = dn_neigh_lookup(&dn_neigh_table, &addr)) != NULL)
+		goto got_route;
+
+	if (dev == NULL)
+		return -EINVAL;
+
+	/* FIXME: We need to change this for routing nodes */
+	/* Send to default router if that doesn't work */
+	if ((neigh = neigh_lookup(&dn_neigh_table, &addr, dev)) != NULL)
+		goto got_route;
+
+	/* Send to default device (and hope for the best) if above fail */
+	if ((neigh = __neigh_lookup(&dn_neigh_table, &addr, dev, 1)) != NULL)
+		goto got_route;
+
+
+	return -EINVAL;
+
+got_route:
+
+	if ((rt = dst_alloc(sizeof(struct dn_route), &dn_dst_ops)) == NULL) {
+		neigh_release(neigh);
+		return -EINVAL;
+	}
+
+	dn_db = (struct dn_dev *)neigh->dev->dn_ptr;
+	
+	rt->rt_saddr = decnet_address;
+	rt->rt_daddr = dest;
+	rt->rt_oif = neigh->dev->ifindex;
+	rt->rt_iif = 0;
+
+	rt->u.dst.neighbour = neigh;
+	rt->u.dst.dev = neigh->dev;
+	rt->u.dst.lastuse = jiffies;
+	rt->u.dst.output = dn_output;
+	rt->u.dst.input  = dn_rt_bug;
+
+	if (dn_dev_islocal(neigh->dev, rt->rt_daddr))
+		rt->u.dst.input = dn_nsp_rx;
+
+	dn_insert_route(rt);
+	sk->dst_cache = &rt->u.dst;
+
+	return 0;
+}
+
+int dn_route_output(struct sock *sk)
+{
+	struct dn_scp *scp = &sk->protinfo.dn;
+	dn_address dest = dn_saddr2dn(&scp->peer);
+	unsigned hash = dn_hash(dest);
+	struct dn_route *rt = NULL;
+	unsigned short src = dn_saddr2dn(&scp->addr);
+
+	start_bh_atomic();
+	for(rt = dn_route_cache[hash]; rt; rt = rt->u.rt_next) {
+		if ((dest == rt->rt_daddr) &&
+				(src == rt->rt_saddr) &&
+				(rt->rt_iif == 0) &&
+				(rt->rt_oif != 0)) {
+			rt->u.dst.lastuse = jiffies;
+			atomic_inc(&rt->u.dst.use);
+			atomic_inc(&rt->u.dst.refcnt);
+			end_bh_atomic();
+			sk->dst_cache = &rt->u.dst;
+			return 0;
+		}
+	}
+	end_bh_atomic();
+
+	return dn_route_output_slow(sk);
+}
+
+static int dn_route_input_slow(struct sk_buff *skb)
+{
+	struct dn_route *rt = NULL;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	struct device *dev = skb->dev;
+	struct neighbour *neigh = NULL;
+	unsigned char addr[6];
+
+	/*
+	 * 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.
+	 */
+	if (dn_dev_islocal(dev, cb->src))
+		return 1;
+
+#ifdef CONFIG_DECNET_ROUTER
+	if ((decnet_node_type == DN_RT_INFO_L1RT) || (decnet_node_type == DN_RT_INFO_L2RT)) {
+#if 0
+		struct dn_fib_ent *fe = NULL;
+
+		fe = dn_fib_lookup(cb->src, cb->dst);
+
+		/* Try routing table first */
+		if (fe != NULL) {
+			neigh = neigh_clone(fe->neigh);
+			dn_fib_release(fe);
+			goto got_route;
+		}
+#endif
+	}
+#endif
+
+	dn_dn2eth(addr, cb->src);
+
+	/* Now see if we are directly connected */
+	if ((neigh = dn_neigh_lookup(&dn_neigh_table, &addr)) != NULL)
+		goto got_route;
+
+	if (dev == NULL)
+		return -EINVAL;
+
+	/* FIXME: Try the default router here .... */
+
+	if ((neigh = __neigh_lookup(&dn_neigh_table, &addr, dev, 1)) != NULL)
+		goto got_route;
+
+	return -EINVAL;
+
+got_route:
+
+	if ((rt = dst_alloc(sizeof(struct dn_route), &dn_dst_ops)) == NULL) {
+                neigh_release(neigh);
+                return -EINVAL;
+        }
+
+	rt->rt_saddr = cb->dst;
+	rt->rt_daddr = cb->src;
+	rt->rt_oif = 0;
+	rt->rt_iif = neigh->dev->ifindex;
+
+	rt->u.dst.neighbour = neigh;
+	rt->u.dst.dev = neigh->dev;
+	rt->u.dst.lastuse = jiffies;
+	rt->u.dst.output = dn_output;
+
+	switch(decnet_node_type) {
+		case DN_RT_INFO_ENDN:
+			rt->u.dst.input = dn_blackhole;
+			break;
+#ifdef CONFIG_DECNET_ROUTER
+		case DN_RT_INFO_L1RT:
+			rt->u.dst.input = dn_l1_forward;
+			break;
+		case DN_RT_INFO_L2RT:
+			rt->u.dst.input = dn_l2_forward;
+			break;
+#endif /* CONFIG_DECNET_ROUTER */
+		default:
+			rt->u.dst.input = dn_blackhole;
+			if (net_ratelimit())
+				printk(KERN_DEBUG "dn_route_input_slow: What kind of node are we?\n");
+	}
+
+	if (dn_dev_islocal(dev, cb->dst))
+		rt->u.dst.input = dn_nsp_rx;
+
+	dn_insert_route(rt);
+	skb->dst = (struct dst_entry *)rt;
+
+	return 0;
+}
+
+int dn_route_input(struct sk_buff *skb)
+{
+	struct dn_route *rt;
+	struct dn_skb_cb *cb = (struct dn_skb_cb *)skb->cb;
+	unsigned hash = dn_hash(cb->src);
+
+	if (skb->dst)
+		return 0;
+
+	for(rt = dn_route_cache[hash]; rt != NULL; rt = rt->u.rt_next) {
+		if ((rt->rt_saddr == cb->dst) &&
+				(rt->rt_daddr == cb->src) &&
+				(rt->rt_oif == 0) &&
+				(rt->rt_iif == cb->iif)) {
+			rt->u.dst.lastuse = jiffies;
+			atomic_inc(&rt->u.dst.use);
+			atomic_inc(&rt->u.dst.refcnt);
+			skb->dst = (struct dst_entry *)rt;
+			return 0;
+		}
+	}
+
+	return dn_route_input_slow(skb);
+}
+
+#ifdef CONFIG_DECNET_ROUTER
+#ifdef CONFIG_RTNETLINK
+static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq, int event, int nowait)
+{
+	struct dn_route *rt = (struct dn_route *)skb->dst;
+	struct rtmsg *r;
+	struct nlmsghdr *nlh;
+	unsigned char *b = skb->tail;
+
+	nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(*r));
+	r = NLMSG_DATA(nlh);
+	nlh->nlmsg_flags = nowait ? NLM_F_MULTI : 0;
+	r->rtm_family = AF_DECnet;
+	r->rtm_dst_len = 16;
+	r->rtm_src_len = 16;
+	r->rtm_tos = 0;
+	r->rtm_table = 0;
+	r->rtm_type = 0;
+	r->rtm_scope = RT_SCOPE_UNIVERSE;
+	r->rtm_protocol = RTPROT_UNSPEC;
+	RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
+	RTA_PUT(skb, RTA_SRC, 2, &rt->rt_saddr);
+	if (rt->u.dst.dev)
+		RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
+	if (rt->u.dst.window)
+		RTA_PUT(skb, RTAX_WINDOW, sizeof(unsigned), &rt->u.dst.window);
+	if (rt->u.dst.rtt)
+		RTA_PUT(skb, RTAX_RTT, sizeof(unsigned), &rt->u.dst.rtt);
+
+	nlh->nlmsg_len = skb->tail - b;
+	return skb->len;
+
+nlmsg_failure:
+rtattr_failure:
+        skb_trim(skb, b - skb->data);
+        return -1;
+}
+
+int dn_fib_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
+{
+	struct rtattr **rta = arg;
+	/* struct rtmsg *rtm = NLMSG_DATA(nlh); */
+	struct dn_route *rt = NULL;
+	dn_address dst = 0;
+	dn_address src = 0;
+	int iif = 0;
+	int err;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (skb == NULL)
+		return -ENOBUFS;
+	skb->mac.raw = skb->data;
+
+	if (rta[RTA_SRC-1])
+		memcpy(&src, RTA_DATA(rta[RTA_SRC-1]), 2);
+	if (rta[RTA_DST-1])
+		memcpy(&dst, RTA_DATA(rta[RTA_DST-1]), 2);
+	if (rta[RTA_IIF-1])
+		memcpy(&iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
+
+	if (iif) {
+		struct device *dev;
+		if ((dev = dev_get_by_index(iif)) == NULL)
+			return -ENODEV;
+		if (!dev->dn_ptr)
+			return -ENODEV;
+		skb->protocol = __constant_htons(ETH_P_DNA_RT);
+		skb->dev = dev;
+		start_bh_atomic();
+		err = dn_route_input(skb);
+		end_bh_atomic();
+		rt = (struct dn_route *)skb->dst;
+		if (!err && rt->u.dst.error)
+			err = rt->u.dst.error;
+	} else {
+		int oif = 0;
+		if (rta[RTA_OIF-1])
+			memcpy(&oif, RTA_DATA(rta[RTA_OIF-1]), sizeof(int));
+		err = -EOPNOTSUPP;
+	}
+	if (err) {
+		kfree_skb(skb);
+		return err;
+	}
+	skb->dst = &rt->u.dst;
+
+	NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
+
+	err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0);
+
+	if (err == 0)
+		return 0;
+	if (err < 0)
+		return -EMSGSIZE;
+
+	err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
+
+	return err;
+}
+#endif /* CONFIG_RTNETLINK */
+#endif /* CONFIG_DECNET_ROUTER */
+
+#ifdef CONFIG_PROC_FS
+
+static int decnet_cache_get_info(char *buffer, char **start, off_t offset, int length, int dummy)
+{
+        int len = 0;
+        off_t pos = 0;
+        off_t begin = 0;
+	struct dn_route *rt;
+	int i;
+	char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
+
+	start_bh_atomic();
+	for(i = 0; i < DN_HASHBUCKETS; i++) {
+		rt = dn_route_cache[i];
+		for(; rt != NULL; rt = rt->u.rt_next) {
+			len += sprintf(buffer + len, "%-8s %-7s %-7s %04d %04d %04d\n",
+					rt->u.dst.dev ? rt->u.dst.dev->name : "*",
+					dn_addr2asc(dn_ntohs(rt->rt_daddr), buf1),
+					dn_addr2asc(dn_ntohs(rt->rt_saddr), buf2),
+					atomic_read(&rt->u.dst.use),
+					atomic_read(&rt->u.dst.refcnt),
+					(int)rt->u.dst.rtt
+					);
+
+	                pos = begin + len;
+	
+        	        if (pos < offset) {
+                	        len   = 0;
+                        	begin = pos;
+                	}
+              		if (pos > offset + length)
+                	        break;
+		}
+		if (pos > offset + length)
+			break;
+	}
+	end_bh_atomic();
+
+        *start = buffer + (offset - begin);
+        len   -= (offset - begin);
+
+        if (len > length) len = length;
+
+        return(len);
+} 
+
+static struct proc_dir_entry proc_net_decnet_cache = {
+        PROC_NET_DN_CACHE, 12, "decnet_cache",
+        S_IFREG | S_IRUGO, 1, 0, 0,
+        0, &proc_net_inode_operations,
+        decnet_cache_get_info
+};
+
+#endif /* CONFIG_PROC_FS */
+
+void __init dn_route_init(void)
+{
+	memset(dn_route_cache, 0, sizeof(struct dn_route *) * DN_HASHBUCKETS);
+
+	dn_route_timer.function = dn_dst_check_expire;
+	dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
+	add_timer(&dn_route_timer);
+
+#ifdef CONFIG_PROC_FS
+	proc_net_register(&proc_net_decnet_cache);
+#endif /* CONFIG_PROC_FS */
+}
+
+#ifdef CONFIG_DECNET_MODULE
+void dn_route_cleanup(void)
+{
+	del_timer(&dn_route_timer);
+	dn_run_flush(0);
+#ifdef CONFIG_PROC_FS
+	proc_net_unregister(PROC_NET_DN_CACHE);
+#endif /* CONFIG_PROC_FS */
+}
+#endif /* CONFIG_DECNET_MODULE */
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)