Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1225 insertions, 0 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
new file mode 100644
index 0000000..405740b
--- /dev/null
+++ b/net/ipv6/ip6_fib.c
@@ -0,0 +1,1225 @@
+/*
+ *	Linux INET6 implementation 
+ *	Forwarding Information Database
+ *
+ *	Authors:
+ *	Pedro Roque		<roque@di.fc.ul.pt>	
+ *
+ *	$Id: ip6_fib.c,v 1.25 2001/10/31 21:55:55 davem Exp $
+ *
+ *	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 (at your option) any later version.
+ */
+
+/*
+ * 	Changes:
+ * 	Yuji SEKIYA @USAGI:	Support default route on router node;
+ * 				remove ip6_null_entry from the top of
+ * 				routing table.
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/net.h>
+#include <linux/route.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/init.h>
+
+#ifdef 	CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#endif
+
+#include <net/ipv6.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+
+#define RT6_DEBUG 2
+
+#if RT6_DEBUG >= 3
+#define RT6_TRACE(x...) printk(KERN_DEBUG x)
+#else
+#define RT6_TRACE(x...) do { ; } while (0)
+#endif
+
+struct rt6_statistics	rt6_stats;
+
+static kmem_cache_t * fib6_node_kmem;
+
+enum fib_walk_state_t
+{
+#ifdef CONFIG_IPV6_SUBTREES
+	FWS_S,
+#endif
+	FWS_L,
+	FWS_R,
+	FWS_C,
+	FWS_U
+};
+
+struct fib6_cleaner_t
+{
+	struct fib6_walker_t w;
+	int (*func)(struct rt6_info *, void *arg);
+	void *arg;
+};
+
+DEFINE_RWLOCK(fib6_walker_lock);
+
+
+#ifdef CONFIG_IPV6_SUBTREES
+#define FWS_INIT FWS_S
+#define SUBTREE(fn) ((fn)->subtree)
+#else
+#define FWS_INIT FWS_L
+#define SUBTREE(fn) NULL
+#endif
+
+static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt);
+static struct fib6_node * fib6_repair_tree(struct fib6_node *fn);
+
+/*
+ *	A routing update causes an increase of the serial number on the
+ *	affected subtree. This allows for cached routes to be asynchronously
+ *	tested when modifications are made to the destination cache as a
+ *	result of redirects, path MTU changes, etc.
+ */
+
+static __u32 rt_sernum;
+
+static struct timer_list ip6_fib_timer = TIMER_INITIALIZER(fib6_run_gc, 0, 0);
+
+struct fib6_walker_t fib6_walker_list = {
+	.prev	= &fib6_walker_list,
+	.next	= &fib6_walker_list, 
+};
+
+#define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next)
+
+static __inline__ u32 fib6_new_sernum(void)
+{
+	u32 n = ++rt_sernum;
+	if ((__s32)n <= 0)
+		rt_sernum = n = 1;
+	return n;
+}
+
+/*
+ *	Auxiliary address test functions for the radix tree.
+ *
+ *	These assume a 32bit processor (although it will work on 
+ *	64bit processors)
+ */
+
+/*
+ *	test bit
+ */
+
+static __inline__ int addr_bit_set(void *token, int fn_bit)
+{
+	__u32 *addr = token;
+
+	return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5];
+}
+
+/*
+ *	find the first different bit between two addresses
+ *	length of address must be a multiple of 32bits
+ */
+
+static __inline__ int addr_diff(void *token1, void *token2, int addrlen)
+{
+	__u32 *a1 = token1;
+	__u32 *a2 = token2;
+	int i;
+
+	addrlen >>= 2;
+
+	for (i = 0; i < addrlen; i++) {
+		__u32 xb;
+
+		xb = a1[i] ^ a2[i];
+
+		if (xb) {
+			int j = 31;
+
+			xb = ntohl(xb);
+
+			while ((xb & (1 << j)) == 0)
+				j--;
+
+			return (i * 32 + 31 - j);
+		}
+	}
+
+	/*
+	 *	we should *never* get to this point since that 
+	 *	would mean the addrs are equal
+	 *
+	 *	However, we do get to it 8) And exacly, when
+	 *	addresses are equal 8)
+	 *
+	 *	ip route add 1111::/128 via ...
+	 *	ip route add 1111::/64 via ...
+	 *	and we are here.
+	 *
+	 *	Ideally, this function should stop comparison
+	 *	at prefix length. It does not, but it is still OK,
+	 *	if returned value is greater than prefix length.
+	 *					--ANK (980803)
+	 */
+
+	return addrlen<<5;
+}
+
+static __inline__ struct fib6_node * node_alloc(void)
+{
+	struct fib6_node *fn;
+
+	if ((fn = kmem_cache_alloc(fib6_node_kmem, SLAB_ATOMIC)) != NULL)
+		memset(fn, 0, sizeof(struct fib6_node));
+
+	return fn;
+}
+
+static __inline__ void node_free(struct fib6_node * fn)
+{
+	kmem_cache_free(fib6_node_kmem, fn);
+}
+
+static __inline__ void rt6_release(struct rt6_info *rt)
+{
+	if (atomic_dec_and_test(&rt->rt6i_ref))
+		dst_free(&rt->u.dst);
+}
+
+
+/*
+ *	Routing Table
+ *
+ *	return the appropriate node for a routing tree "add" operation
+ *	by either creating and inserting or by returning an existing
+ *	node.
+ */
+
+static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
+				     int addrlen, int plen,
+				     int offset)
+{
+	struct fib6_node *fn, *in, *ln;
+	struct fib6_node *pn = NULL;
+	struct rt6key *key;
+	int	bit;
+       	int	dir = 0;
+	__u32	sernum = fib6_new_sernum();
+
+	RT6_TRACE("fib6_add_1\n");
+
+	/* insert node in tree */
+
+	fn = root;
+
+	do {
+		key = (struct rt6key *)((u8 *)fn->leaf + offset);
+
+		/*
+		 *	Prefix match
+		 */
+		if (plen < fn->fn_bit ||
+		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
+			goto insert_above;
+		
+		/*
+		 *	Exact match ?
+		 */
+			 
+		if (plen == fn->fn_bit) {
+			/* clean up an intermediate node */
+			if ((fn->fn_flags & RTN_RTINFO) == 0) {
+				rt6_release(fn->leaf);
+				fn->leaf = NULL;
+			}
+			
+			fn->fn_sernum = sernum;
+				
+			return fn;
+		}
+
+		/*
+		 *	We have more bits to go
+		 */
+			 
+		/* Try to walk down on tree. */
+		fn->fn_sernum = sernum;
+		dir = addr_bit_set(addr, fn->fn_bit);
+		pn = fn;
+		fn = dir ? fn->right: fn->left;
+	} while (fn);
+
+	/*
+	 *	We walked to the bottom of tree.
+	 *	Create new leaf node without children.
+	 */
+
+	ln = node_alloc();
+
+	if (ln == NULL)
+		return NULL;
+	ln->fn_bit = plen;
+			
+	ln->parent = pn;
+	ln->fn_sernum = sernum;
+
+	if (dir)
+		pn->right = ln;
+	else
+		pn->left  = ln;
+
+	return ln;
+
+
+insert_above:
+	/*
+	 * split since we don't have a common prefix anymore or 
+	 * we have a less significant route.
+	 * we've to insert an intermediate node on the list
+	 * this new node will point to the one we need to create
+	 * and the current
+	 */
+
+	pn = fn->parent;
+
+	/* find 1st bit in difference between the 2 addrs.
+
+	   See comment in addr_diff: bit may be an invalid value,
+	   but if it is >= plen, the value is ignored in any case.
+	 */
+	
+	bit = addr_diff(addr, &key->addr, addrlen);
+
+	/* 
+	 *		(intermediate)[in]	
+	 *	          /	   \
+	 *	(new leaf node)[ln] (old node)[fn]
+	 */
+	if (plen > bit) {
+		in = node_alloc();
+		ln = node_alloc();
+		
+		if (in == NULL || ln == NULL) {
+			if (in)
+				node_free(in);
+			if (ln)
+				node_free(ln);
+			return NULL;
+		}
+
+		/* 
+		 * new intermediate node. 
+		 * RTN_RTINFO will
+		 * be off since that an address that chooses one of
+		 * the branches would not match less specific routes
+		 * in the other branch
+		 */
+
+		in->fn_bit = bit;
+
+		in->parent = pn;
+		in->leaf = fn->leaf;
+		atomic_inc(&in->leaf->rt6i_ref);
+
+		in->fn_sernum = sernum;
+
+		/* update parent pointer */
+		if (dir)
+			pn->right = in;
+		else
+			pn->left  = in;
+
+		ln->fn_bit = plen;
+
+		ln->parent = in;
+		fn->parent = in;
+
+		ln->fn_sernum = sernum;
+
+		if (addr_bit_set(addr, bit)) {
+			in->right = ln;
+			in->left  = fn;
+		} else {
+			in->left  = ln;
+			in->right = fn;
+		}
+	} else { /* plen <= bit */
+
+		/* 
+		 *		(new leaf node)[ln]
+		 *	          /	   \
+		 *	     (old node)[fn] NULL
+		 */
+
+		ln = node_alloc();
+
+		if (ln == NULL)
+			return NULL;
+
+		ln->fn_bit = plen;
+
+		ln->parent = pn;
+
+		ln->fn_sernum = sernum;
+		
+		if (dir)
+			pn->right = ln;
+		else
+			pn->left  = ln;
+
+		if (addr_bit_set(&key->addr, plen))
+			ln->right = fn;
+		else
+			ln->left  = fn;
+
+		fn->parent = ln;
+	}
+	return ln;
+}
+
+/*
+ *	Insert routing information in a node.
+ */
+
+static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
+    struct nlmsghdr *nlh)
+{
+	struct rt6_info *iter = NULL;
+	struct rt6_info **ins;
+
+	ins = &fn->leaf;
+
+	if (fn->fn_flags&RTN_TL_ROOT &&
+	    fn->leaf == &ip6_null_entry &&
+	    !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){
+		fn->leaf = rt;
+		rt->u.next = NULL;
+		goto out;
+	}
+
+	for (iter = fn->leaf; iter; iter=iter->u.next) {
+		/*
+		 *	Search for duplicates
+		 */
+
+		if (iter->rt6i_metric == rt->rt6i_metric) {
+			/*
+			 *	Same priority level
+			 */
+
+			if (iter->rt6i_dev == rt->rt6i_dev &&
+			    iter->rt6i_idev == rt->rt6i_idev &&
+			    ipv6_addr_equal(&iter->rt6i_gateway,
+					    &rt->rt6i_gateway)) {
+				if (!(iter->rt6i_flags&RTF_EXPIRES))
+					return -EEXIST;
+				iter->rt6i_expires = rt->rt6i_expires;
+				if (!(rt->rt6i_flags&RTF_EXPIRES)) {
+					iter->rt6i_flags &= ~RTF_EXPIRES;
+					iter->rt6i_expires = 0;
+				}
+				return -EEXIST;
+			}
+		}
+
+		if (iter->rt6i_metric > rt->rt6i_metric)
+			break;
+
+		ins = &iter->u.next;
+	}
+
+	/*
+	 *	insert node
+	 */
+
+out:
+	rt->u.next = iter;
+	*ins = rt;
+	rt->rt6i_node = fn;
+	atomic_inc(&rt->rt6i_ref);
+	inet6_rt_notify(RTM_NEWROUTE, rt, nlh);
+	rt6_stats.fib_rt_entries++;
+
+	if ((fn->fn_flags & RTN_RTINFO) == 0) {
+		rt6_stats.fib_route_nodes++;
+		fn->fn_flags |= RTN_RTINFO;
+	}
+
+	return 0;
+}
+
+static __inline__ void fib6_start_gc(struct rt6_info *rt)
+{
+	if (ip6_fib_timer.expires == 0 &&
+	    (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
+		mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
+}
+
+void fib6_force_start_gc(void)
+{
+	if (ip6_fib_timer.expires == 0)
+		mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
+}
+
+/*
+ *	Add routing information to the routing tree.
+ *	<destination addr>/<source addr>
+ *	with source addr info in sub-trees
+ */
+
+int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr)
+{
+	struct fib6_node *fn;
+	int err = -ENOMEM;
+
+	fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
+			rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
+
+	if (fn == NULL)
+		goto out;
+
+#ifdef CONFIG_IPV6_SUBTREES
+	if (rt->rt6i_src.plen) {
+		struct fib6_node *sn;
+
+		if (fn->subtree == NULL) {
+			struct fib6_node *sfn;
+
+			/*
+			 * Create subtree.
+			 *
+			 *		fn[main tree]
+			 *		|
+			 *		sfn[subtree root]
+			 *		   \
+			 *		    sn[new leaf node]
+			 */
+
+			/* Create subtree root node */
+			sfn = node_alloc();
+			if (sfn == NULL)
+				goto st_failure;
+
+			sfn->leaf = &ip6_null_entry;
+			atomic_inc(&ip6_null_entry.rt6i_ref);
+			sfn->fn_flags = RTN_ROOT;
+			sfn->fn_sernum = fib6_new_sernum();
+
+			/* Now add the first leaf node to new subtree */
+
+			sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
+					sizeof(struct in6_addr), rt->rt6i_src.plen,
+					offsetof(struct rt6_info, rt6i_src));
+
+			if (sn == NULL) {
+				/* If it is failed, discard just allocated
+				   root, and then (in st_failure) stale node
+				   in main tree.
+				 */
+				node_free(sfn);
+				goto st_failure;
+			}
+
+			/* Now link new subtree to main tree */
+			sfn->parent = fn;
+			fn->subtree = sfn;
+			if (fn->leaf == NULL) {
+				fn->leaf = rt;
+				atomic_inc(&rt->rt6i_ref);
+			}
+		} else {
+			sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
+					sizeof(struct in6_addr), rt->rt6i_src.plen,
+					offsetof(struct rt6_info, rt6i_src));
+
+			if (sn == NULL)
+				goto st_failure;
+		}
+
+		fn = sn;
+	}
+#endif
+
+	err = fib6_add_rt2node(fn, rt, nlh);
+
+	if (err == 0) {
+		fib6_start_gc(rt);
+		if (!(rt->rt6i_flags&RTF_CACHE))
+			fib6_prune_clones(fn, rt);
+	}
+
+out:
+	if (err)
+		dst_free(&rt->u.dst);
+	return err;
+
+#ifdef CONFIG_IPV6_SUBTREES
+	/* Subtree creation failed, probably main tree node
+	   is orphan. If it is, shoot it.
+	 */
+st_failure:
+	if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
+		fib6_repair_tree(fn);
+	dst_free(&rt->u.dst);
+	return err;
+#endif
+}
+
+/*
+ *	Routing tree lookup
+ *
+ */
+
+struct lookup_args {
+	int		offset;		/* key offset on rt6_info	*/
+	struct in6_addr	*addr;		/* search key			*/
+};
+
+static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
+					struct lookup_args *args)
+{
+	struct fib6_node *fn;
+	int dir;
+
+	/*
+	 *	Descend on a tree
+	 */
+
+	fn = root;
+
+	for (;;) {
+		struct fib6_node *next;
+
+		dir = addr_bit_set(args->addr, fn->fn_bit);
+
+		next = dir ? fn->right : fn->left;
+
+		if (next) {
+			fn = next;
+			continue;
+		}
+
+		break;
+	}
+
+	while ((fn->fn_flags & RTN_ROOT) == 0) {
+#ifdef CONFIG_IPV6_SUBTREES
+		if (fn->subtree) {
+			struct fib6_node *st;
+			struct lookup_args *narg;
+
+			narg = args + 1;
+
+			if (narg->addr) {
+				st = fib6_lookup_1(fn->subtree, narg);
+
+				if (st && !(st->fn_flags & RTN_ROOT))
+					return st;
+			}
+		}
+#endif
+
+		if (fn->fn_flags & RTN_RTINFO) {
+			struct rt6key *key;
+
+			key = (struct rt6key *) ((u8 *) fn->leaf +
+						 args->offset);
+
+			if (ipv6_prefix_equal(&key->addr, args->addr, key->plen))
+				return fn;
+		}
+
+		fn = fn->parent;
+	}
+
+	return NULL;
+}
+
+struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
+			       struct in6_addr *saddr)
+{
+	struct lookup_args args[2];
+	struct fib6_node *fn;
+
+	args[0].offset = offsetof(struct rt6_info, rt6i_dst);
+	args[0].addr = daddr;
+
+#ifdef CONFIG_IPV6_SUBTREES
+	args[1].offset = offsetof(struct rt6_info, rt6i_src);
+	args[1].addr = saddr;
+#endif
+
+	fn = fib6_lookup_1(root, args);
+
+	if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
+		fn = root;
+
+	return fn;
+}
+
+/*
+ *	Get node with specified destination prefix (and source prefix,
+ *	if subtrees are used)
+ */
+
+
+static struct fib6_node * fib6_locate_1(struct fib6_node *root,
+					struct in6_addr *addr,
+					int plen, int offset)
+{
+	struct fib6_node *fn;
+
+	for (fn = root; fn ; ) {
+		struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
+
+		/*
+		 *	Prefix match
+		 */
+		if (plen < fn->fn_bit ||
+		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
+			return NULL;
+
+		if (plen == fn->fn_bit)
+			return fn;
+
+		/*
+		 *	We have more bits to go
+		 */
+		if (addr_bit_set(addr, fn->fn_bit))
+			fn = fn->right;
+		else
+			fn = fn->left;
+	}
+	return NULL;
+}
+
+struct fib6_node * fib6_locate(struct fib6_node *root,
+			       struct in6_addr *daddr, int dst_len,
+			       struct in6_addr *saddr, int src_len)
+{
+	struct fib6_node *fn;
+
+	fn = fib6_locate_1(root, daddr, dst_len,
+			   offsetof(struct rt6_info, rt6i_dst));
+
+#ifdef CONFIG_IPV6_SUBTREES
+	if (src_len) {
+		BUG_TRAP(saddr!=NULL);
+		if (fn == NULL)
+			fn = fn->subtree;
+		if (fn)
+			fn = fib6_locate_1(fn, saddr, src_len,
+					   offsetof(struct rt6_info, rt6i_src));
+	}
+#endif
+
+	if (fn && fn->fn_flags&RTN_RTINFO)
+		return fn;
+
+	return NULL;
+}
+
+
+/*
+ *	Deletion
+ *
+ */
+
+static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
+{
+	if (fn->fn_flags&RTN_ROOT)
+		return &ip6_null_entry;
+
+	while(fn) {
+		if(fn->left)
+			return fn->left->leaf;
+
+		if(fn->right)
+			return fn->right->leaf;
+
+		fn = SUBTREE(fn);
+	}
+	return NULL;
+}
+
+/*
+ *	Called to trim the tree of intermediate nodes when possible. "fn"
+ *	is the node we want to try and remove.
+ */
+
+static struct fib6_node * fib6_repair_tree(struct fib6_node *fn)
+{
+	int children;
+	int nstate;
+	struct fib6_node *child, *pn;
+	struct fib6_walker_t *w;
+	int iter = 0;
+
+	for (;;) {
+		RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
+		iter++;
+
+		BUG_TRAP(!(fn->fn_flags&RTN_RTINFO));
+		BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT));
+		BUG_TRAP(fn->leaf==NULL);
+
+		children = 0;
+		child = NULL;
+		if (fn->right) child = fn->right, children |= 1;
+		if (fn->left) child = fn->left, children |= 2;
+
+		if (children == 3 || SUBTREE(fn) 
+#ifdef CONFIG_IPV6_SUBTREES
+		    /* Subtree root (i.e. fn) may have one child */
+		    || (children && fn->fn_flags&RTN_ROOT)
+#endif
+		    ) {
+			fn->leaf = fib6_find_prefix(fn);
+#if RT6_DEBUG >= 2
+			if (fn->leaf==NULL) {
+				BUG_TRAP(fn->leaf);
+				fn->leaf = &ip6_null_entry;
+			}
+#endif
+			atomic_inc(&fn->leaf->rt6i_ref);
+			return fn->parent;
+		}
+
+		pn = fn->parent;
+#ifdef CONFIG_IPV6_SUBTREES
+		if (SUBTREE(pn) == fn) {
+			BUG_TRAP(fn->fn_flags&RTN_ROOT);
+			SUBTREE(pn) = NULL;
+			nstate = FWS_L;
+		} else {
+			BUG_TRAP(!(fn->fn_flags&RTN_ROOT));
+#endif
+			if (pn->right == fn) pn->right = child;
+			else if (pn->left == fn) pn->left = child;
+#if RT6_DEBUG >= 2
+			else BUG_TRAP(0);
+#endif
+			if (child)
+				child->parent = pn;
+			nstate = FWS_R;
+#ifdef CONFIG_IPV6_SUBTREES
+		}
+#endif
+
+		read_lock(&fib6_walker_lock);
+		FOR_WALKERS(w) {
+			if (child == NULL) {
+				if (w->root == fn) {
+					w->root = w->node = NULL;
+					RT6_TRACE("W %p adjusted by delroot 1\n", w);
+				} else if (w->node == fn) {
+					RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
+					w->node = pn;
+					w->state = nstate;
+				}
+			} else {
+				if (w->root == fn) {
+					w->root = child;
+					RT6_TRACE("W %p adjusted by delroot 2\n", w);
+				}
+				if (w->node == fn) {
+					w->node = child;
+					if (children&2) {
+						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
+						w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
+					} else {
+						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
+						w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
+					}
+				}
+			}
+		}
+		read_unlock(&fib6_walker_lock);
+
+		node_free(fn);
+		if (pn->fn_flags&RTN_RTINFO || SUBTREE(pn))
+			return pn;
+
+		rt6_release(pn->leaf);
+		pn->leaf = NULL;
+		fn = pn;
+	}
+}
+
+static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
+    struct nlmsghdr *nlh, void *_rtattr)
+{
+	struct fib6_walker_t *w;
+	struct rt6_info *rt = *rtp;
+
+	RT6_TRACE("fib6_del_route\n");
+
+	/* Unlink it */
+	*rtp = rt->u.next;
+	rt->rt6i_node = NULL;
+	rt6_stats.fib_rt_entries--;
+	rt6_stats.fib_discarded_routes++;
+
+	/* Adjust walkers */
+	read_lock(&fib6_walker_lock);
+	FOR_WALKERS(w) {
+		if (w->state == FWS_C && w->leaf == rt) {
+			RT6_TRACE("walker %p adjusted by delroute\n", w);
+			w->leaf = rt->u.next;
+			if (w->leaf == NULL)
+				w->state = FWS_U;
+		}
+	}
+	read_unlock(&fib6_walker_lock);
+
+	rt->u.next = NULL;
+
+	if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT)
+		fn->leaf = &ip6_null_entry;
+
+	/* If it was last route, expunge its radix tree node */
+	if (fn->leaf == NULL) {
+		fn->fn_flags &= ~RTN_RTINFO;
+		rt6_stats.fib_route_nodes--;
+		fn = fib6_repair_tree(fn);
+	}
+
+	if (atomic_read(&rt->rt6i_ref) != 1) {
+		/* This route is used as dummy address holder in some split
+		 * nodes. It is not leaked, but it still holds other resources,
+		 * which must be released in time. So, scan ascendant nodes
+		 * and replace dummy references to this route with references
+		 * to still alive ones.
+		 */
+		while (fn) {
+			if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
+				fn->leaf = fib6_find_prefix(fn);
+				atomic_inc(&fn->leaf->rt6i_ref);
+				rt6_release(rt);
+			}
+			fn = fn->parent;
+		}
+		/* No more references are possible at this point. */
+		if (atomic_read(&rt->rt6i_ref) != 1) BUG();
+	}
+
+	inet6_rt_notify(RTM_DELROUTE, rt, nlh);
+	rt6_release(rt);
+}
+
+int fib6_del(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr)
+{
+	struct fib6_node *fn = rt->rt6i_node;
+	struct rt6_info **rtp;
+
+#if RT6_DEBUG >= 2
+	if (rt->u.dst.obsolete>0) {
+		BUG_TRAP(fn==NULL);
+		return -ENOENT;
+	}
+#endif
+	if (fn == NULL || rt == &ip6_null_entry)
+		return -ENOENT;
+
+	BUG_TRAP(fn->fn_flags&RTN_RTINFO);
+
+	if (!(rt->rt6i_flags&RTF_CACHE))
+		fib6_prune_clones(fn, rt);
+
+	/*
+	 *	Walk the leaf entries looking for ourself
+	 */
+
+	for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.next) {
+		if (*rtp == rt) {
+			fib6_del_route(fn, rtp, nlh, _rtattr);
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+/*
+ *	Tree traversal function.
+ *
+ *	Certainly, it is not interrupt safe.
+ *	However, it is internally reenterable wrt itself and fib6_add/fib6_del.
+ *	It means, that we can modify tree during walking
+ *	and use this function for garbage collection, clone pruning,
+ *	cleaning tree when a device goes down etc. etc.	
+ *
+ *	It guarantees that every node will be traversed,
+ *	and that it will be traversed only once.
+ *
+ *	Callback function w->func may return:
+ *	0 -> continue walking.
+ *	positive value -> walking is suspended (used by tree dumps,
+ *	and probably by gc, if it will be split to several slices)
+ *	negative value -> terminate walking.
+ *
+ *	The function itself returns:
+ *	0   -> walk is complete.
+ *	>0  -> walk is incomplete (i.e. suspended)
+ *	<0  -> walk is terminated by an error.
+ */
+
+int fib6_walk_continue(struct fib6_walker_t *w)
+{
+	struct fib6_node *fn, *pn;
+
+	for (;;) {
+		fn = w->node;
+		if (fn == NULL)
+			return 0;
+
+		if (w->prune && fn != w->root &&
+		    fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
+			w->state = FWS_C;
+			w->leaf = fn->leaf;
+		}
+		switch (w->state) {
+#ifdef CONFIG_IPV6_SUBTREES
+		case FWS_S:
+			if (SUBTREE(fn)) {
+				w->node = SUBTREE(fn);
+				continue;
+			}
+			w->state = FWS_L;
+#endif	
+		case FWS_L:
+			if (fn->left) {
+				w->node = fn->left;
+				w->state = FWS_INIT;
+				continue;
+			}
+			w->state = FWS_R;
+		case FWS_R:
+			if (fn->right) {
+				w->node = fn->right;
+				w->state = FWS_INIT;
+				continue;
+			}
+			w->state = FWS_C;
+			w->leaf = fn->leaf;
+		case FWS_C:
+			if (w->leaf && fn->fn_flags&RTN_RTINFO) {
+				int err = w->func(w);
+				if (err)
+					return err;
+				continue;
+			}
+			w->state = FWS_U;
+		case FWS_U:
+			if (fn == w->root)
+				return 0;
+			pn = fn->parent;
+			w->node = pn;
+#ifdef CONFIG_IPV6_SUBTREES
+			if (SUBTREE(pn) == fn) {
+				BUG_TRAP(fn->fn_flags&RTN_ROOT);
+				w->state = FWS_L;
+				continue;
+			}
+#endif
+			if (pn->left == fn) {
+				w->state = FWS_R;
+				continue;
+			}
+			if (pn->right == fn) {
+				w->state = FWS_C;
+				w->leaf = w->node->leaf;
+				continue;
+			}
+#if RT6_DEBUG >= 2
+			BUG_TRAP(0);
+#endif
+		}
+	}
+}
+
+int fib6_walk(struct fib6_walker_t *w)
+{
+	int res;
+
+	w->state = FWS_INIT;
+	w->node = w->root;
+
+	fib6_walker_link(w);
+	res = fib6_walk_continue(w);
+	if (res <= 0)
+		fib6_walker_unlink(w);
+	return res;
+}
+
+static int fib6_clean_node(struct fib6_walker_t *w)
+{
+	int res;
+	struct rt6_info *rt;
+	struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w;
+
+	for (rt = w->leaf; rt; rt = rt->u.next) {
+		res = c->func(rt, c->arg);
+		if (res < 0) {
+			w->leaf = rt;
+			res = fib6_del(rt, NULL, NULL);
+			if (res) {
+#if RT6_DEBUG >= 2
+				printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
+#endif
+				continue;
+			}
+			return 0;
+		}
+		BUG_TRAP(res==0);
+	}
+	w->leaf = rt;
+	return 0;
+}
+
+/*
+ *	Convenient frontend to tree walker.
+ *	
+ *	func is called on each route.
+ *		It may return -1 -> delete this route.
+ *		              0  -> continue walking
+ *
+ *	prune==1 -> only immediate children of node (certainly,
+ *	ignoring pure split nodes) will be scanned.
+ */
+
+void fib6_clean_tree(struct fib6_node *root,
+		     int (*func)(struct rt6_info *, void *arg),
+		     int prune, void *arg)
+{
+	struct fib6_cleaner_t c;
+
+	c.w.root = root;
+	c.w.func = fib6_clean_node;
+	c.w.prune = prune;
+	c.func = func;
+	c.arg = arg;
+
+	fib6_walk(&c.w);
+}
+
+static int fib6_prune_clone(struct rt6_info *rt, void *arg)
+{
+	if (rt->rt6i_flags & RTF_CACHE) {
+		RT6_TRACE("pruning clone %p\n", rt);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt)
+{
+	fib6_clean_tree(fn, fib6_prune_clone, 1, rt);
+}
+
+/*
+ *	Garbage collection
+ */
+
+static struct fib6_gc_args
+{
+	int			timeout;
+	int			more;
+} gc_args;
+
+static int fib6_age(struct rt6_info *rt, void *arg)
+{
+	unsigned long now = jiffies;
+
+	/*
+	 *	check addrconf expiration here.
+	 *	Routes are expired even if they are in use.
+	 *
+	 *	Also age clones. Note, that clones are aged out
+	 *	only if they are not in use now.
+	 */
+
+	if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
+		if (time_after(now, rt->rt6i_expires)) {
+			RT6_TRACE("expiring %p\n", rt);
+			rt6_reset_dflt_pointer(rt);
+			return -1;
+		}
+		gc_args.more++;
+	} else if (rt->rt6i_flags & RTF_CACHE) {
+		if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
+		    time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
+			RT6_TRACE("aging clone %p\n", rt);
+			return -1;
+		} else if ((rt->rt6i_flags & RTF_GATEWAY) &&
+			   (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
+			RT6_TRACE("purging route %p via non-router but gateway\n",
+				  rt);
+			return -1;
+		}
+		gc_args.more++;
+	}
+
+	return 0;
+}
+
+static DEFINE_SPINLOCK(fib6_gc_lock);
+
+void fib6_run_gc(unsigned long dummy)
+{
+	if (dummy != ~0UL) {
+		spin_lock_bh(&fib6_gc_lock);
+		gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval;
+	} else {
+		local_bh_disable();
+		if (!spin_trylock(&fib6_gc_lock)) {
+			mod_timer(&ip6_fib_timer, jiffies + HZ);
+			local_bh_enable();
+			return;
+		}
+		gc_args.timeout = ip6_rt_gc_interval;
+	}
+	gc_args.more = 0;
+
+
+	write_lock_bh(&rt6_lock);
+	ndisc_dst_gc(&gc_args.more);
+	fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL);
+	write_unlock_bh(&rt6_lock);
+
+	if (gc_args.more)
+		mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
+	else {
+		del_timer(&ip6_fib_timer);
+		ip6_fib_timer.expires = 0;
+	}
+	spin_unlock_bh(&fib6_gc_lock);
+}
+
+void __init fib6_init(void)
+{
+	fib6_node_kmem = kmem_cache_create("fib6_nodes",
+					   sizeof(struct fib6_node),
+					   0, SLAB_HWCACHE_ALIGN,
+					   NULL, NULL);
+	if (!fib6_node_kmem)
+		panic("cannot create fib6_nodes cache");
+}
+
+void fib6_gc_cleanup(void)
+{
+	del_timer(&ip6_fib_timer);
+	kmem_cache_destroy(fib6_node_kmem);
+}