text: /*
   * 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 acknowledgment:
   *	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
   *
   */
  
  /*
   * Routines to build and maintain radix trees for routing lookups.
   */
  
  #include "ftconfig.h"
  #include "ftlib.h"
  
  #include "radix.h"
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <errno.h>
  #include <string.h>
  #include <time.h>
  #include <sys/time.h>
  #include <sys/types.h>
  
  
  #if !defined(sgi) && !defined(__NetBSD__)
  static char sccsid[] __attribute__((unused)) = "@(#)rdisc.c	8.1 (Berkeley) x/y/95";
  #elif defined(__NetBSD__)
  __RCSID("$NetBSD$");
  #endif
  #ident "$FreeBSD: src/sbin/routed/radix.c,v 1.5 1999/09/05 17:49:11 peter Exp $"
  
  #define LOG_ERR 0
  #define LOG_DEBUG 0
  
  #define log(x, msg) fterr_warnx(msg);
  #define panic(s) {log(1,s); exit(1);}
  
  #define min(a,b) (((a)<(b))?(a):(b))
  
  static void *rtmalloc(size_t size, const char *msg);
  
  static void *rtmalloc(size_t size, const char *msg)
  {
    void *p;
  
    if (!(p = malloc(size)))
      fterr_err(1, "malloc(): %s", msg);
    return p;
  } /* rtmalloc */
  
  
  int	max_keylen;
  struct radix_mask *rn_mkfreelist;
  struct radix_node_head *mask_rnhead;
  static char *addmask_key;
  static char normal_chars[] = {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
  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), (size_t)l))
  
  static int rn_satisfies_leaf(char *, struct radix_node *, int);
  
  /*
   * 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(void *v_arg,
  	  struct radix_node *head)
  {
  	struct radix_node *x;
  	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(void *v_arg,
  	    struct radix_node *head,
  	    void *m_arg)
  {
  	struct radix_node *x;
  	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(void* m_arg, void *n_arg)
  {
  	caddr_t m = m_arg, n = n_arg;
  	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(void *v_arg, void *m_arg, struct radix_node_head *head)
  {
  	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_satisfies_leaf(char *trial,
  		  struct radix_node *leaf,
  		  int skip)
  {
  	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(void *v_arg,
  	 struct radix_node_head *head)
  {
  	caddr_t v = v_arg;
  	struct radix_node *t = head->rnh_treetop, *x;
  	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;
  	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!
  	 * Or 255.255.255.255
  	 *
  	 * In this case, we have a complete match of the key.  Unless
  	 * the node is one of the roots, we are finished.
  	 * If it is the zeros root, then take what we have, prefering
  	 * any real data.
  	 * If it is the ones root, then pretend the target key was followed
  	 * by a byte of zeros.
  	 */
  	if (!(t->rn_flags & RNF_ROOT))
  		return t;		/* not a root */
  	if (t->rn_dupedkey) {
  		t = t->rn_dupedkey;
  		return t;		/* have some real data */
  	}
  	if (*(cp-1) == 0)
  		return t;		/* not the ones root */
  	b = 0;				/* fake a zero after 255.255.255.255 */
  	goto on2;
  on1:
  	test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
  	for (b = 7; (test >>= 1) > 0;)
  		b--;
  on2:
  	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_satisfies_leaf(v, t, matched_off)) {
  			return t;
  		}
  	}
  	t = saved_t;
  	/* start searching up the tree */
  	do {
  		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_satisfies_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(void *v, int b, struct radix_node nodes[2])
  {
  	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(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);
  	struct radix_node *t = rn_search(v_arg, top);
  	caddr_t cp = v + head_off;
  	int b;
  	struct radix_node *tt;
  
  	/*
  	 * Find first bit at which v and t->rn_key differ
  	 */
      {
  		caddr_t cp2 = t->rn_key + head_off;
  		int cmp_res;
  	caddr_t cplim = v + vlen;
  
  	while (cp < cplim)
  		if (*cp2++ != *cp++)
  			goto on1;
  	/* handle adding 255.255.255.255 */
  	if (!(t->rn_flags & RNF_ROOT) || *(cp2-1) == 0) {
  		*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;
      }
      {
  	    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 ((unsigned)b > (unsigned)x->rn_b);
  #ifdef RN_DEBUG
  	if (rn_debug)
  		log(LOG_DEBUG, "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(void *n_arg, int search, int skip)
  {
  	caddr_t netmask = (caddr_t)n_arg;
  	struct radix_node *x;
  	caddr_t cp, cplim;
  	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)
  		Bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
  	if ((m0 = mlen) > skip)
  		Bcopy(netmask + skip, addmask_key + 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)
  		Bzero(addmask_key + m0, last_zeroed - m0);
  	*addmask_key = last_zeroed = mlen;
  	x = rn_search(addmask_key, rn_masktop);
  	if (Bcmp(addmask_key, x->rn_key, mlen) != 0)
  		x = 0;
  	if (x || search)
  		return (x);
  	x = (struct radix_node *)rtmalloc(max_keylen + 2*sizeof(*x),
  					  "rn_addmask");
  	saved_x = x;
  	Bzero(x, max_keylen + 2 * sizeof (*x));
  	netmask = cp = (caddr_t)(x + 2);
  	Bcopy(addmask_key, cp, mlen);
  	x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
  	if (maskduplicated) {
  		log(LOG_ERR, "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(void *m_arg, void *n_arg)
  {
  	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(struct radix_node *tt,
  		  struct radix_mask *next)
  {
  	struct radix_mask *m;
  
  	MKGet(m);
  	if (m == 0) {
  		log(LOG_ERR, "Mask for route not entered\n");
  		return (0);
  	}
  	Bzero(m, 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(void *v_arg,
  	    void *n_arg,
  	    struct radix_node_head *head,
  	    struct radix_node treenodes[2])
  {
  	caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
  	struct radix_node *t, *x = 0, *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) {
  				log(LOG_ERR,
  				   "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(void *v_arg,
  	  void *netmask_arg,
  	  struct radix_node_head *head)
  {
  	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 ||
  	    Bcmp(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) {
  			log(LOG_ERR, "rn_delete: inconsistent annotation\n");
  			return 0;  /* dangling ref could cause disaster */
  		}
  	} else {
  		if (m->rm_mask != tt->rn_mask) {
  			log(LOG_ERR, "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) {
  		log(LOG_ERR, "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 log(LOG_ERR, "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 (m)
  				log(LOG_ERR, "rn_delete: Orphaned Mask");
  		}
  	}
  	/*
  	 * 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(struct radix_node_head *h,
  	    int (*f)(struct radix_node *, struct walkarg *),
  	    struct walkarg *w)
  {
  	int error;
  	struct radix_node *base, *next;
  	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(void **head, int off)
  {
  	struct radix_node_head *rnh;
  	struct radix_node *t, *tt, *ttt;
  	if (*head)
  		return (1);
  	rnh = (struct radix_node_head *)rtmalloc(sizeof(*rnh), "rn_inithead");
  	Bzero(rnh, 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(void)
  {
  	char *cp, *cplim;
  	if (max_keylen == 0) {
  		printf("rn_init: radix functions require max_keylen be set\n");
  		return;
  	}
  	rn_zeros = (char *)rtmalloc(3 * max_keylen, "rn_init");
  	Bzero(rn_zeros, 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)
  		panic("rn_init 2");
  }
  
  