/*
 * $Id: radix.c,v 1.1.1.1 2003/08/18 05:40:24 kaohj Exp $
 *
 * DEBUG: section 53     Radix tree data structure implementation
 * AUTHOR: NetBSD Derived
 *
 * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from the
 *  Internet community.  Development is led by Duane Wessels of the
 *  National Laboratory for Applied Network Research and funded by the
 *  National Science Foundation.  Squid is Copyrighted (C) 1998 by
 *  the Regents of the University of California.  Please see the
 *  COPYRIGHT file for full details.  Squid incorporates software
 *  developed and/or copyrighted by other sources.  Please see the
 *  CREDITS file for full details.
 *
 *  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.
 *  
 *  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.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */


/*
 * Copyright (c) 1988, 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)radix.c     8.4 (Berkeley) 11/2/94
 */

#include "config.h"

#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STDIO_H
#include <stdio.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_CTYPE_H
#include <ctype.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_GRP_H
#include <grp.h>
#endif
#if HAVE_GNUMALLOC_H
#include <gnumalloc.h>
#elif HAVE_MALLOC_H && !defined(_SQUID_FREEBSD_) && !defined(_SQUID_NEXT_)
#include <malloc.h>
#endif
#if HAVE_MEMORY_H
#include <memory.h>
#endif
#if HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#if HAVE_ASSERT_H
#include <assert.h>
#endif

#include "util.h"

#include "radix.h"

int max_keylen;
struct radix_mask *rn_mkfreelist;
struct radix_node_head *mask_rnhead;
static char *addmask_key;
static unsigned char normal_chars[] =
{0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xFF};
static char *rn_zeros, *rn_ones;

#define rn_masktop (mask_rnhead->rnh_treetop)
#undef Bcmp
#define Bcmp(a, b, l) (l == 0 ? 0 : memcmp((caddr_t)(a), (caddr_t)(b), (u_long)l))
/*
 * The data structure for the keys is a radix tree with one way
 * branching removed.  The index rn_b at an internal node n represents a bit
 * position to be tested.  The tree is arranged so that all descendants
 * of a node n have keys whose bits all agree up to position rn_b - 1.
 * (We say the index of n is rn_b.)
 *
 * There is at least one descendant which has a one bit at position rn_b,
 * and at least one with a zero there.
 *
 * A route is determined by a pair of key and mask.  We require that the
 * bit-wise logical and of the key and mask to be the key.
 * We define the index of a route to associated with the mask to be
 * the first bit number in the mask where 0 occurs (with bit number 0
 * representing the highest order bit).
 * 
 * We say a mask is normal if every bit is 0, past the index of the mask.
 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
 * and m is a normal mask, then the route applies to every descendant of n.
 * If the index(m) < rn_b, this implies the trailing last few bits of k
 * before bit b are all 0, (and hence consequently true of every descendant
 * of n), so the route applies to all descendants of the node as well.
 * 
 * Similar logic shows that a non-normal mask m such that
 * index(m) <= index(n) could potentially apply to many children of n.
 * Thus, for each non-host route, we attach its mask to a list at an internal
 * node as high in the tree as we can go. 
 *
 * The present version of the code makes use of normal routes in short-
 * circuiting an explict mask and compare operation when testing whether
 * a key satisfies a normal route, and also in remembering the unique leaf
 * that governs a subtree.
 */

struct radix_node *
rn_search(v_arg, head)
     void *v_arg;
     struct radix_node *head;
{
    register struct radix_node *x;
    register caddr_t v;

    for (x = head, v = v_arg; x->rn_b >= 0;) {
	if (x->rn_bmask & v[x->rn_off])
	    x = x->rn_r;
	else
	    x = x->rn_l;
    }
    return (x);
}

struct radix_node *
rn_search_m(v_arg, head, m_arg)
     struct radix_node *head;
     void *v_arg, *m_arg;
{
    register struct radix_node *x;
    register caddr_t v = v_arg, m = m_arg;

    for (x = head; x->rn_b >= 0;) {
	if ((x->rn_bmask & m[x->rn_off]) &&
	    (x->rn_bmask & v[x->rn_off]))
	    x = x->rn_r;
	else
	    x = x->rn_l;
    }
    return x;
}

int
rn_refines(m_arg, n_arg)
     void *m_arg, *n_arg;
{
    register caddr_t m = m_arg, n = n_arg;
    register caddr_t lim, lim2 = lim = n + *(u_char *) n;
    int longer = (*(u_char *) n++) - (int) (*(u_char *) m++);
    int masks_are_equal = 1;

    if (longer > 0)
	lim -= longer;
    while (n < lim) {
	if (*n & ~(*m))
	    return 0;
	if (*n++ != *m++)
	    masks_are_equal = 0;
    }
    while (n < lim2)
	if (*n++)
	    return 0;
    if (masks_are_equal && (longer < 0))
	for (lim2 = m - longer; m < lim2;)
	    if (*m++)
		return 1;
    return (!masks_are_equal);
}

struct radix_node *
rn_lookup(v_arg, m_arg, head)
     void *v_arg, *m_arg;
     struct radix_node_head *head;
{
    register struct radix_node *x;
    caddr_t netmask = 0;

    if (m_arg) {
	if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == 0)
	    return (0);
	netmask = x->rn_key;
    }
    x = rn_match(v_arg, head);
    if (x && netmask) {
	while (x && x->rn_mask != netmask)
	    x = x->rn_dupedkey;
    }
    return x;
}

static
int
rn_satsifies_leaf(trial, leaf, skip)
     char *trial;
     register struct radix_node *leaf;
     int skip;
{
    register char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
    char *cplim;
    int length = min(*(u_char *) cp, *(u_char *) cp2);

    if (cp3 == 0)
	cp3 = rn_ones;
    else
	length = min(length, *(u_char *) cp3);
    cplim = cp + length;
    cp3 += skip;
    cp2 += skip;
    for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
	if ((*cp ^ *cp2) & *cp3)
	    return 0;
    return 1;
}

struct radix_node *
rn_match(v_arg, head)
     void *v_arg;
     struct radix_node_head *head;
{
    caddr_t v = v_arg;
    register struct radix_node *t = head->rnh_treetop, *x;
    register caddr_t cp = v, cp2;
    caddr_t cplim;
    struct radix_node *saved_t, *top = t;
    int off = t->rn_off, vlen = *(u_char *) cp, matched_off;
    register int test, b, rn_b;

    /*
     * Open code rn_search(v, top) to avoid overhead of extra
     * subroutine call.
     */
    for (; t->rn_b >= 0;) {
	if (t->rn_bmask & cp[t->rn_off])
	    t = t->rn_r;
	else
	    t = t->rn_l;
    }
    /*
     * See if we match exactly as a host destination
     * or at least learn how many bits match, for normal mask finesse.
     *
     * It doesn't hurt us to limit how many bytes to check
     * to the length of the mask, since if it matches we had a genuine
     * match and the leaf we have is the most specific one anyway;
     * if it didn't match with a shorter length it would fail
     * with a long one.  This wins big for class B&C netmasks which
     * are probably the most common case...
     */
    if (t->rn_mask)
	vlen = *(u_char *) t->rn_mask;
    cp += off;
    cp2 = t->rn_key + off;
    cplim = v + vlen;
    for (; cp < cplim; cp++, cp2++)
	if (*cp != *cp2)
	    goto on1;
    /*
     * This extra grot is in case we are explicitly asked
     * to look up the default.  Ugh!
     */
    if ((t->rn_flags & RNF_ROOT) && t->rn_dupedkey)
	t = t->rn_dupedkey;
    return t;
  on1:
    test = (*cp ^ *cp2) & 0xff;	/* find first bit that differs */
    for (b = 7; (test >>= 1) > 0;)
	b--;
    matched_off = cp - v;
    b += matched_off << 3;
    rn_b = -1 - b;
    /*
     * If there is a host route in a duped-key chain, it will be first.
     */
    if ((saved_t = t)->rn_mask == 0)
	t = t->rn_dupedkey;
    for (; t; t = t->rn_dupedkey)
	/*
	 * Even if we don't match exactly as a host,
	 * we may match if the leaf we wound up at is
	 * a route to a net.
	 */
	if (t->rn_flags & RNF_NORMAL) {
	    if (rn_b <= t->rn_b)
		return t;
	} else if (rn_satsifies_leaf(v, t, matched_off))
	    return t;
    t = saved_t;
    /* start searching up the tree */
    do {
	register struct radix_mask *m;
	t = t->rn_p;
	if ((m = t->rn_mklist)) {
	    /*
	     * If non-contiguous masks ever become important
	     * we can restore the masking and open coding of
	     * the search and satisfaction test and put the
	     * calculation of "off" back before the "do".
	     */
	    do {
		if (m->rm_flags & RNF_NORMAL) {
		    if (rn_b <= m->rm_b)
			return (m->rm_leaf);
		} else {
		    off = min(t->rn_off, matched_off);
		    x = rn_search_m(v, t, m->rm_mask);
		    while (x && x->rn_mask != m->rm_mask)
			x = x->rn_dupedkey;
		    if (x && rn_satsifies_leaf(v, x, off))
			return x;
		}
	    } while ((m = m->rm_mklist));
	}
    } while (t != top);
    return 0;
}

#ifdef RN_DEBUG
int rn_nodenum;
struct radix_node *rn_clist;
int rn_saveinfo;
int rn_debug = 1;
#endif

struct radix_node *
rn_newpair(v, b, nodes)
     void *v;
     int b;
     struct radix_node nodes[2];
{
    register struct radix_node *tt = nodes, *t = tt + 1;
    t->rn_b = b;
    t->rn_bmask = 0x80 >> (b & 7);
    t->rn_l = tt;
    t->rn_off = b >> 3;
    tt->rn_b = -1;
    tt->rn_key = (caddr_t) v;
    tt->rn_p = t;
    tt->rn_flags = t->rn_flags = RNF_ACTIVE;
#ifdef RN_DEBUG
    tt->rn_info = rn_nodenum++;
    t->rn_info = rn_nodenum++;
    tt->rn_twin = t;
    tt->rn_ybro = rn_clist;
    rn_clist = tt;
#endif
    return t;
}

struct radix_node *
rn_insert(v_arg, head, dupentry, nodes)
     void *v_arg;
     struct radix_node_head *head;
     int *dupentry;
     struct radix_node nodes[2];
{
    caddr_t v = v_arg;
    struct radix_node *top = head->rnh_treetop;
    int head_off = top->rn_off, vlen = (int) *((u_char *) v);
    register struct radix_node *t = rn_search(v_arg, top);
    register caddr_t cp = v + head_off;
    register int b;
    struct radix_node *tt;
    /*
     * Find first bit at which v and t->rn_key differ
     */
    {
	register caddr_t cp2 = t->rn_key + head_off;
	register int cmp_res;
	caddr_t cplim = v + vlen;

	while (cp < cplim)
	    if (*cp2++ != *cp++)
		goto on1;
	*dupentry = 1;
	return t;
      on1:
	*dupentry = 0;
	cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
	for (b = (cp - v) << 3; cmp_res; b--)
	    cmp_res >>= 1;
    }
    {
	register struct radix_node *p, *x = top;
	cp = v;
	do {
	    p = x;
	    if (cp[x->rn_off] & x->rn_bmask)
		x = x->rn_r;
	    else
		x = x->rn_l;
	} while (b > (unsigned) x->rn_b);	/* x->rn_b < b && x->rn_b >= 0 */
#ifdef RN_DEBUG
	if (rn_debug)
	    fprintf(stderr, "rn_insert: Going In:\n");
	traverse(p);
#endif
	t = rn_newpair(v_arg, b, nodes);
	tt = t->rn_l;
	if ((cp[p->rn_off] & p->rn_bmask) == 0)
	    p->rn_l = t;
	else
	    p->rn_r = t;
	x->rn_p = t;
	t->rn_p = p;		/* frees x, p as temp vars below */
	if ((cp[t->rn_off] & t->rn_bmask) == 0) {
	    t->rn_r = x;
	} else {
	    t->rn_r = tt;
	    t->rn_l = x;
	}
#ifdef RN_DEBUG
	if (rn_debug)
	    log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
#endif
    }
    return (tt);
}

struct radix_node *
rn_addmask(n_arg, search, skip)
     int search, skip;
     void *n_arg;
{
    caddr_t netmask = (caddr_t) n_arg;
    register struct radix_node *x;
    register caddr_t cp, cplim;
    register int b = 0, mlen, j;
    int maskduplicated, m0, isnormal;
    struct radix_node *saved_x;
    static int last_zeroed = 0;

    if ((mlen = *(u_char *) netmask) > max_keylen)
	mlen = max_keylen;
    if (skip == 0)
	skip = 1;
    if (mlen <= skip)
	return (mask_rnhead->rnh_nodes);
    if (skip > 1)
	memcpy(addmask_key + 1, rn_ones + 1, skip - 1);
    if ((m0 = mlen) > skip)
	memcpy(addmask_key + skip, netmask + skip, mlen - skip);
    /*
     * Trim trailing zeroes.
     */
    for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
	cp--;
    mlen = cp - addmask_key;
    if (mlen <= skip) {
	if (m0 >= last_zeroed)
	    last_zeroed = mlen;
	return (mask_rnhead->rnh_nodes);
    }
    if (m0 < last_zeroed)
	memset(addmask_key + m0, '\0', last_zeroed - m0);
    *addmask_key = last_zeroed = mlen;
    x = rn_search(addmask_key, rn_masktop);
    if (memcmp(addmask_key, x->rn_key, mlen) != 0)
	x = 0;
    if (x || search)
	return (x);
    R_Malloc(x, struct radix_node *, max_keylen + 2 * sizeof(*x));
    if ((saved_x = x) == 0)
	return (0);
    memset(x, '\0', max_keylen + 2 * sizeof(*x));
    netmask = cp = (caddr_t) (x + 2);
    memcpy(cp, addmask_key, mlen);
    x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
    if (maskduplicated) {
	fprintf(stderr, "rn_addmask: mask impossibly already in tree");
	Free(saved_x);
	return (x);
    }
    /*
     * Calculate index of mask, and check for normalcy.
     */
    cplim = netmask + mlen;
    isnormal = 1;
    for (cp = netmask + skip; (cp < cplim) && *(u_char *) cp == 0xff;)
	cp++;
    if (cp != cplim) {
	for (j = 0x80; (j & *cp) != 0; j >>= 1)
	    b++;
	if (*cp != normal_chars[b] || cp != (cplim - 1))
	    isnormal = 0;
    }
    b += (cp - netmask) << 3;
    x->rn_b = -1 - b;
    if (isnormal)
	x->rn_flags |= RNF_NORMAL;
    return (x);
}

static int			/* XXX: arbitrary ordering for non-contiguous masks */
rn_lexobetter(m_arg, n_arg)
     void *m_arg, *n_arg;
{
    register u_char *mp = m_arg, *np = n_arg, *lim;

    if (*mp > *np)
	return 1;		/* not really, but need to check longer one first */
    if (*mp == *np)
	for (lim = mp + *mp; mp < lim;)
	    if (*mp++ > *np++)
		return 1;
    return 0;
}

static struct radix_mask *
rn_new_radix_mask(tt, next)
     register struct radix_node *tt;
     register struct radix_mask *next;
{
    register struct radix_mask *m;

    MKGet(m);
    if (m == 0) {
	fprintf(stderr, "Mask for route not entered\n");
	return (0);
    }
    memset(m, '\0', sizeof *m);
    m->rm_b = tt->rn_b;
    m->rm_flags = tt->rn_flags;
    if (tt->rn_flags & RNF_NORMAL)
	m->rm_leaf = tt;
    else
	m->rm_mask = tt->rn_mask;
    m->rm_mklist = next;
    tt->rn_mklist = m;
    return m;
}

struct radix_node *
rn_addroute(v_arg, n_arg, head, treenodes)
     void *v_arg, *n_arg;
     struct radix_node_head *head;
     struct radix_node treenodes[2];
{
    caddr_t v = (caddr_t) v_arg, netmask = (caddr_t) n_arg;
    register struct radix_node *t, *x = NULL, *tt;
    struct radix_node *saved_tt, *top = head->rnh_treetop;
    short b = 0, b_leaf = 0;
    int keyduplicated;
    caddr_t mmask;
    struct radix_mask *m, **mp;

    /*
     * In dealing with non-contiguous masks, there may be
     * many different routes which have the same mask.
     * We will find it useful to have a unique pointer to
     * the mask to speed avoiding duplicate references at
     * nodes and possibly save time in calculating indices.
     */
    if (netmask) {
	if ((x = rn_addmask(netmask, 0, top->rn_off)) == 0)
	    return (0);
	b_leaf = x->rn_b;
	b = -1 - x->rn_b;
	netmask = x->rn_key;
    }
    /*
     * Deal with duplicated keys: attach node to previous instance
     */
    saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
    if (keyduplicated) {
	for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
	    if (tt->rn_mask == netmask)
		return (0);
	    if (netmask == 0 ||
		(tt->rn_mask &&
		    ((b_leaf < tt->rn_b) ||	/* index(netmask) > node */
			rn_refines(netmask, tt->rn_mask) ||
			rn_lexobetter(netmask, tt->rn_mask))))
		break;
	}
	/*
	 * If the mask is not duplicated, we wouldn't
	 * find it among possible duplicate key entries
	 * anyway, so the above test doesn't hurt.
	 *
	 * We sort the masks for a duplicated key the same way as
	 * in a masklist -- most specific to least specific.
	 * This may require the unfortunate nuisance of relocating
	 * the head of the list.
	 */
	if (tt == saved_tt) {
	    struct radix_node *xx = x;
	    /* link in at head of list */
	    (tt = treenodes)->rn_dupedkey = t;
	    tt->rn_flags = t->rn_flags;
	    tt->rn_p = x = t->rn_p;
	    if (x->rn_l == t)
		x->rn_l = tt;
	    else
		x->rn_r = tt;
	    saved_tt = tt;
	    x = xx;
	} else {
	    (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
	    t->rn_dupedkey = tt;
	}
#ifdef RN_DEBUG
	t = tt + 1;
	tt->rn_info = rn_nodenum++;
	t->rn_info = rn_nodenum++;
	tt->rn_twin = t;
	tt->rn_ybro = rn_clist;
	rn_clist = tt;
#endif
	tt->rn_key = (caddr_t) v;
	tt->rn_b = -1;
	tt->rn_flags = RNF_ACTIVE;
    }
    /*
     * Put mask in tree.
     */
    if (netmask) {
	tt->rn_mask = netmask;
	tt->rn_b = x->rn_b;
	tt->rn_flags |= x->rn_flags & RNF_NORMAL;
    }
    t = saved_tt->rn_p;
    if (keyduplicated)
	goto on2;
    b_leaf = -1 - t->rn_b;
    if (t->rn_r == saved_tt)
	x = t->rn_l;
    else
	x = t->rn_r;
    /* Promote general routes from below */
    if (x->rn_b < 0) {
	for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
	    if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) {
		if ((*mp = m = rn_new_radix_mask(x, 0)))
		    mp = &m->rm_mklist;
	    }
    } else if (x->rn_mklist) {
	/*
	 * Skip over masks whose index is > that of new node
	 */
	for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
	    if (m->rm_b >= b_leaf)
		break;
	t->rn_mklist = m;
	*mp = 0;
    }
  on2:
    /* Add new route to highest possible ancestor's list */
    if ((netmask == 0) || (b > t->rn_b))
	return tt;		/* can't lift at all */
    b_leaf = tt->rn_b;
    do {
	x = t;
	t = t->rn_p;
    } while (b <= t->rn_b && x != top);
    /*
     * Search through routes associated with node to
     * insert new route according to index.
     * Need same criteria as when sorting dupedkeys to avoid
     * double loop on deletion.
     */
    for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
	if (m->rm_b < b_leaf)
	    continue;
	if (m->rm_b > b_leaf)
	    break;
	if (m->rm_flags & RNF_NORMAL) {
	    mmask = m->rm_leaf->rn_mask;
	    if (tt->rn_flags & RNF_NORMAL) {
		fprintf(stderr,
		    "Non-unique normal route, mask not entered");
		return tt;
	    }
	} else
	    mmask = m->rm_mask;
	if (mmask == netmask) {
	    m->rm_refs++;
	    tt->rn_mklist = m;
	    return tt;
	}
	if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
	    break;
    }
    *mp = rn_new_radix_mask(tt, *mp);
    return tt;
}

struct radix_node *
rn_delete(v_arg, netmask_arg, head)
     void *v_arg, *netmask_arg;
     struct radix_node_head *head;
{
    register struct radix_node *t, *p, *x, *tt;
    struct radix_mask *m, *saved_m, **mp;
    struct radix_node *dupedkey, *saved_tt, *top;
    caddr_t v, netmask;
    int b, head_off, vlen;

    v = v_arg;
    netmask = netmask_arg;
    x = head->rnh_treetop;
    tt = rn_search(v, x);
    head_off = x->rn_off;
    vlen = *(u_char *) v;
    saved_tt = tt;
    top = x;
    if (tt == 0 ||
	memcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
	return (0);
    /*
     * Delete our route from mask lists.
     */
    if (netmask) {
	if ((x = rn_addmask(netmask, 1, head_off)) == 0)
	    return (0);
	netmask = x->rn_key;
	while (tt->rn_mask != netmask)
	    if ((tt = tt->rn_dupedkey) == 0)
		return (0);
    }
    if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
	goto on1;
    if (tt->rn_flags & RNF_NORMAL) {
	if (m->rm_leaf != tt || m->rm_refs > 0) {
	    fprintf(stderr, "rn_delete: inconsistent annotation\n");
	    return 0;		/* dangling ref could cause disaster */
	}
    } else {
	if (m->rm_mask != tt->rn_mask) {
	    fprintf(stderr, "rn_delete: inconsistent annotation\n");
	    goto on1;
	}
	if (--m->rm_refs >= 0)
	    goto on1;
    }
    b = -1 - tt->rn_b;
    t = saved_tt->rn_p;
    if (b > t->rn_b)
	goto on1;		/* Wasn't lifted at all */
    do {
	x = t;
	t = t->rn_p;
    } while (b <= t->rn_b && x != top);
    for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
	if (m == saved_m) {
	    *mp = m->rm_mklist;
	    MKFree(m);
	    break;
	}
    if (m == 0) {
	fprintf(stderr, "rn_delete: couldn't find our annotation\n");
	if (tt->rn_flags & RNF_NORMAL)
	    return (0);		/* Dangling ref to us */
    }
  on1:
    /*
     * Eliminate us from tree
     */
    if (tt->rn_flags & RNF_ROOT)
	return (0);
#ifdef RN_DEBUG
    /* Get us out of the creation list */
    for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {
    }
    if (t)
	t->rn_ybro = tt->rn_ybro;
#endif
    t = tt->rn_p;
    if ((dupedkey = saved_tt->rn_dupedkey)) {
	if (tt == saved_tt) {
	    x = dupedkey;
	    x->rn_p = t;
	    if (t->rn_l == tt)
		t->rn_l = x;
	    else
		t->rn_r = x;
	} else {
	    for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
		p = p->rn_dupedkey;
	    if (p)
		p->rn_dupedkey = tt->rn_dupedkey;
	    else
		fprintf(stderr, "rn_delete: couldn't find us\n");
	}
	t = tt + 1;
	if (t->rn_flags & RNF_ACTIVE) {
#ifndef RN_DEBUG
	    *++x = *t;
	    p = t->rn_p;
#else
	    b = t->rn_info;
	    *++x = *t;
	    t->rn_info = b;
	    p = t->rn_p;
#endif
	    if (p->rn_l == t)
		p->rn_l = x;
	    else
		p->rn_r = x;
	    x->rn_l->rn_p = x;
	    x->rn_r->rn_p = x;
	}
	goto out;
    }
    if (t->rn_l == tt)
	x = t->rn_r;
    else
	x = t->rn_l;
    p = t->rn_p;
    if (p->rn_r == t)
	p->rn_r = x;
    else
	p->rn_l = x;
    x->rn_p = p;
    /*
     * Demote routes attached to us.
     */
    if (t->rn_mklist) {
	if (x->rn_b >= 0) {
	    for (mp = &x->rn_mklist; (m = *mp);)
		mp = &m->rm_mklist;
	    *mp = t->rn_mklist;
	} else {
	    /* If there are any key,mask pairs in a sibling
	     * duped-key chain, some subset will appear sorted
	     * in the same order attached to our mklist */
	    for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
		if (m == x->rn_mklist) {
		    struct radix_mask *mm = m->rm_mklist;
		    x->rn_mklist = 0;
		    if (--(m->rm_refs) < 0)
			MKFree(m);
		    m = mm;
		}
#if RN_DEBUG
	    if (m)
		fprintf(stderr, "%s %x at %x\n",
		    "rn_delete: Orphaned Mask", (int) m, (int) x);
#else
	    assert(m == NULL);
#endif
	}
    }
    /*
     * We may be holding an active internal node in the tree.
     */
    x = tt + 1;
    if (t != x) {
#ifndef RN_DEBUG
	*t = *x;
#else
	b = t->rn_info;
	*t = *x;
	t->rn_info = b;
#endif
	t->rn_l->rn_p = t;
	t->rn_r->rn_p = t;
	p = x->rn_p;
	if (p->rn_l == x)
	    p->rn_l = t;
	else
	    p->rn_r = t;
    }
  out:
    tt->rn_flags &= ~RNF_ACTIVE;
    tt[1].rn_flags &= ~RNF_ACTIVE;
    return (tt);
}

int
rn_walktree(h, f, w)
     struct radix_node_head *h;
     int (*f) ();
     void *w;
{
    int error;
    struct radix_node *base, *next;
    register struct radix_node *rn = h->rnh_treetop;
    /*
     * This gets complicated because we may delete the node
     * while applying the function f to it, so we need to calculate
     * the successor node in advance.
     */
    /* First time through node, go left */
    while (rn->rn_b >= 0)
	rn = rn->rn_l;
    for (;;) {
	base = rn;
	/* If at right child go back up, otherwise, go right */
	while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0)
	    rn = rn->rn_p;
	/* Find the next *leaf* since next node might vanish, too */
	for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;)
	    rn = rn->rn_l;
	next = rn;
	/* Process leaves */
	while ((rn = base)) {
	    base = rn->rn_dupedkey;
	    if (!(rn->rn_flags & RNF_ROOT) && (error = (*f) (rn, w)))
		return (error);
	}
	rn = next;
	if (rn->rn_flags & RNF_ROOT)
	    return (0);
    }
    /* NOTREACHED */
}

int
rn_inithead(head, off)
     void **head;
     int off;
{
    register struct radix_node_head *rnh;
    register struct radix_node *t, *tt, *ttt;
    if (*head)
	return (1);
    R_Malloc(rnh, struct radix_node_head *, sizeof(*rnh));
    if (rnh == 0)
	return (0);
    memset(rnh, '\0', sizeof(*rnh));
    *head = rnh;
    t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
    ttt = rnh->rnh_nodes + 2;
    t->rn_r = ttt;
    t->rn_p = t;
    tt = t->rn_l;
    tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
    tt->rn_b = -1 - off;
    *ttt = *tt;
    ttt->rn_key = rn_ones;
    rnh->rnh_addaddr = rn_addroute;
    rnh->rnh_deladdr = rn_delete;
    rnh->rnh_matchaddr = rn_match;
    rnh->rnh_lookup = rn_lookup;
    rnh->rnh_walktree = rn_walktree;
    rnh->rnh_treetop = t;
    return (1);
}

void
rn_init()
{
    char *cp, *cplim;
#ifdef KERNEL
    struct domain *dom;

    for (dom = domains; dom; dom = dom->dom_next)
	if (dom->dom_maxrtkey > max_keylen)
	    max_keylen = dom->dom_maxrtkey;
#endif
    if (max_keylen == 0) {
	fprintf(stderr,
	    "rn_init: radix functions require max_keylen be set\n");
	return;
    }
    R_Malloc(rn_zeros, char *, 3 * max_keylen);
    if (rn_zeros == NULL) {
	fprintf(stderr, "rn_init failed.\n");
	exit(-1);
    }
    memset(rn_zeros, '\0', 3 * max_keylen);
    rn_ones = cp = rn_zeros + max_keylen;
    addmask_key = cplim = rn_ones + max_keylen;
    while (cp < cplim)
	*cp++ = -1;
    if (rn_inithead((void **) &mask_rnhead, 0) == 0) {
	fprintf(stderr, "rn_init2 failed.\n");
	exit(-1);
    }
}
