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 000000000000..405740b75abb
--- /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);
+}