1/*
2 * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * Copyright (c) 1988, 1989, 1993
30 *	The Regents of the University of California.  All rights reserved.
31 *
32 * Redistribution and use in source and binary forms, with or without
33 * modification, are permitted provided that the following conditions
34 * are met:
35 * 1. Redistributions of source code must retain the above copyright
36 *    notice, this list of conditions and the following disclaimer.
37 * 2. Redistributions in binary form must reproduce the above copyright
38 *    notice, this list of conditions and the following disclaimer in the
39 *    documentation and/or other materials provided with the distribution.
40 * 3. All advertising materials mentioning features or use of this software
41 *    must display the following acknowledgement:
42 *	This product includes software developed by the University of
43 *	California, Berkeley and its contributors.
44 * 4. Neither the name of the University nor the names of its contributors
45 *    may be used to endorse or promote products derived from this software
46 *    without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 *
60 *	@(#)radix.c	8.4 (Berkeley) 11/2/94
61 * $FreeBSD: src/sys/net/radix.c,v 1.20.2.2 2001/03/06 00:56:50 obrien Exp $
62 */
63
64/*
65 * Routines to build and maintain radix trees for routing lookups.
66 */
67#ifndef _RADIX_H_
68#include <sys/param.h>
69#ifdef	KERNEL
70#include <sys/systm.h>
71#include <sys/malloc.h>
72#define	M_DONTWAIT M_NOWAIT
73#include <sys/domain.h>
74#else
75#include <stdlib.h>
76#endif
77#include <sys/syslog.h>
78#include <net/radix.h>
79#include <sys/socket.h>
80#include <sys/socketvar.h>
81#include <kern/locks.h>
82#endif
83
84static int	rn_walktree_from(struct radix_node_head *h, void *a,
85				      void *m, walktree_f_t *f, void *w);
86static int rn_walktree(struct radix_node_head *, walktree_f_t *, void *);
87static struct radix_node
88	 *rn_insert(void *, struct radix_node_head *, int *,
89			struct radix_node [2]),
90	 *rn_newpair(void *, int, struct radix_node[2]),
91	 *rn_search(void *, struct radix_node *),
92	 *rn_search_m(void *, struct radix_node *, void *);
93
94static int	max_keylen;
95static struct radix_mask *rn_mkfreelist;
96static struct radix_node_head *mask_rnhead;
97static char *addmask_key;
98static char normal_chars[] = {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
99static char *rn_zeros, *rn_ones;
100
101
102extern lck_grp_t	*domain_proto_mtx_grp;
103extern lck_attr_t	*domain_proto_mtx_attr;
104
105#define rn_masktop (mask_rnhead->rnh_treetop)
106#undef Bcmp
107#define Bcmp(a, b, l) \
108	(l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (uint32_t)l))
109
110static int	rn_lexobetter(void *m_arg, void *n_arg);
111static struct radix_mask *
112		rn_new_radix_mask(struct radix_node *tt,
113				       struct radix_mask *next);
114static int rn_satisfies_leaf(char *trial, struct radix_node *leaf, int skip,
115    rn_matchf_t *f, void *w);
116
117#define	RN_MATCHF(rn, f, arg)	(f == NULL || (*f)((rn), arg))
118
119/*
120 * The data structure for the keys is a radix tree with one way
121 * branching removed.  The index rn_bit at an internal node n represents a bit
122 * position to be tested.  The tree is arranged so that all descendants
123 * of a node n have keys whose bits all agree up to position rn_bit - 1.
124 * (We say the index of n is rn_bit.)
125 *
126 * There is at least one descendant which has a one bit at position rn_bit,
127 * and at least one with a zero there.
128 *
129 * A route is determined by a pair of key and mask.  We require that the
130 * bit-wise logical and of the key and mask to be the key.
131 * We define the index of a route to associated with the mask to be
132 * the first bit number in the mask where 0 occurs (with bit number 0
133 * representing the highest order bit).
134 *
135 * We say a mask is normal if every bit is 0, past the index of the mask.
136 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_bit,
137 * and m is a normal mask, then the route applies to every descendant of n.
138 * If the index(m) < rn_bit, this implies the trailing last few bits of k
139 * before bit b are all 0, (and hence consequently true of every descendant
140 * of n), so the route applies to all descendants of the node as well.
141 *
142 * Similar logic shows that a non-normal mask m such that
143 * index(m) <= index(n) could potentially apply to many children of n.
144 * Thus, for each non-host route, we attach its mask to a list at an internal
145 * node as high in the tree as we can go.
146 *
147 * The present version of the code makes use of normal routes in short-
148 * circuiting an explict mask and compare operation when testing whether
149 * a key satisfies a normal route, and also in remembering the unique leaf
150 * that governs a subtree.
151 */
152
153static struct radix_node *
154rn_search(void *v_arg, struct radix_node *head)
155{
156	struct radix_node *x;
157	caddr_t v;
158
159	for (x = head, v = v_arg; x->rn_bit >= 0;) {
160		if (x->rn_bmask & v[x->rn_offset])
161			x = x->rn_right;
162		else
163			x = x->rn_left;
164	}
165	return (x);
166}
167
168static struct radix_node *
169rn_search_m(void *v_arg, struct radix_node *head, void *m_arg)
170{
171	struct radix_node *x;
172	caddr_t v = v_arg, m = m_arg;
173
174	for (x = head; x->rn_bit >= 0;) {
175		if ((x->rn_bmask & m[x->rn_offset]) &&
176		    (x->rn_bmask & v[x->rn_offset]))
177			x = x->rn_right;
178		else
179			x = x->rn_left;
180	}
181	return x;
182}
183
184int
185rn_refines(void *m_arg, void *n_arg)
186{
187	caddr_t m = m_arg, n = n_arg;
188	caddr_t lim, lim2 = lim = n + *(u_char *)n;
189	int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
190	int masks_are_equal = 1;
191
192	if (longer > 0)
193		lim -= longer;
194	while (n < lim) {
195		if (*n & ~(*m))
196			return 0;
197		if (*n++ != *m++)
198			masks_are_equal = 0;
199	}
200	while (n < lim2)
201		if (*n++)
202			return 0;
203	if (masks_are_equal && (longer < 0))
204		for (lim2 = m - longer; m < lim2; )
205			if (*m++)
206				return 1;
207	return (!masks_are_equal);
208}
209
210struct radix_node *
211rn_lookup(void *v_arg, void *m_arg, struct radix_node_head *head)
212{
213	return (rn_lookup_args(v_arg, m_arg, head, NULL, NULL));
214}
215
216struct radix_node *
217rn_lookup_args(void *v_arg, void *m_arg, struct radix_node_head *head,
218    rn_matchf_t *f, void *w)
219{
220	struct radix_node *x;
221	caddr_t netmask = NULL;
222
223	if (m_arg) {
224		x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_offset);
225		if (x == 0)
226			return (NULL);
227		netmask = x->rn_key;
228	}
229	x = rn_match_args(v_arg, head, f, w);
230	if (x && netmask) {
231		while (x && x->rn_mask != netmask)
232			x = x->rn_dupedkey;
233	}
234	return x;
235}
236
237/*
238 * Returns true if address 'trial' has no bits differing from the
239 * leaf's key when compared under the leaf's mask.  In other words,
240 * returns true when 'trial' matches leaf.  If a leaf-matching
241 * routine is passed in, it is also used to find a match on the
242 * conditions defined by the caller of rn_match.
243 */
244static int
245rn_satisfies_leaf(char *trial, struct radix_node *leaf, int skip,
246    rn_matchf_t *f, void *w)
247{
248	char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
249	char *cplim;
250	int length = min(*(u_char *)cp, *(u_char *)cp2);
251
252	if (cp3 == 0)
253		cp3 = rn_ones;
254	else
255		length = min(length, *(u_char *)cp3);
256	cplim = cp + length; cp3 += skip; cp2 += skip;
257	for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
258		if ((*cp ^ *cp2) & *cp3)
259			return 0;
260
261	return (RN_MATCHF(leaf, f, w));
262}
263
264struct radix_node *
265rn_match(void *v_arg, struct radix_node_head *head)
266{
267	return (rn_match_args(v_arg, head, NULL, NULL));
268}
269
270struct radix_node *
271rn_match_args(void *v_arg, struct radix_node_head *head,
272    rn_matchf_t *f, void *w)
273{
274	caddr_t v = v_arg;
275	struct radix_node *t = head->rnh_treetop, *x;
276	caddr_t cp = v, cp2;
277	caddr_t cplim;
278	struct radix_node *saved_t, *top = t;
279	int off = t->rn_offset, vlen = *(u_char *)cp, matched_off;
280	int test, b, rn_bit;
281
282	/*
283	 * Open code rn_search(v, top) to avoid overhead of extra
284	 * subroutine call.
285	 */
286	for (; t->rn_bit >= 0; ) {
287		if (t->rn_bmask & cp[t->rn_offset])
288			t = t->rn_right;
289		else
290			t = t->rn_left;
291	}
292	/*
293	 * See if we match exactly as a host destination
294	 * or at least learn how many bits match, for normal mask finesse.
295	 *
296	 * It doesn't hurt us to limit how many bytes to check
297	 * to the length of the mask, since if it matches we had a genuine
298	 * match and the leaf we have is the most specific one anyway;
299	 * if it didn't match with a shorter length it would fail
300	 * with a long one.  This wins big for class B&C netmasks which
301	 * are probably the most common case...
302	 */
303	if (t->rn_mask)
304		vlen = *(u_char *)t->rn_mask;
305	cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
306	for (; cp < cplim; cp++, cp2++)
307		if (*cp != *cp2)
308			goto on1;
309	/*
310	 * This extra grot is in case we are explicitly asked
311	 * to look up the default.  Ugh!
312	 *
313	 * Never return the root node itself, it seems to cause a
314	 * lot of confusion.
315	 */
316	if (t->rn_flags & RNF_ROOT)
317		t = t->rn_dupedkey;
318	if (t == NULL || RN_MATCHF(t, f, w)) {
319		return (t);
320	} else {
321		/*
322		 * Although we found an exact match on the key,
323		 * f() is looking for some other criteria as well.
324		 * Continue looking as if the exact match failed.
325		 */
326		if (t->rn_parent->rn_flags & RNF_ROOT) {
327			/* Hit the top; have to give up */
328			return (NULL);
329		}
330		b = 0;
331		goto keeplooking;
332	}
333on1:
334	test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
335	for (b = 7; (test >>= 1) > 0;)
336		b--;
337keeplooking:
338	matched_off = cp - v;
339	b += matched_off << 3;
340	rn_bit = -1 - b;
341	/*
342	 * If there is a host route in a duped-key chain, it will be first.
343	 */
344	if ((saved_t = t)->rn_mask == 0)
345		t = t->rn_dupedkey;
346	for (; t; t = t->rn_dupedkey) {
347		/*
348		 * Even if we don't match exactly as a host,
349		 * we may match if the leaf we wound up at is
350		 * a route to a net.
351		 */
352		if (t->rn_flags & RNF_NORMAL) {
353			if ((rn_bit <= t->rn_bit) && RN_MATCHF(t, f, w))
354				return (t);
355		} else if (rn_satisfies_leaf(v, t, matched_off, f, w)) {
356			return (t);
357		}
358	}
359	t = saved_t;
360	/* start searching up the tree */
361	do {
362		struct radix_mask *m;
363		t = t->rn_parent;
364		m = t->rn_mklist;
365		/*
366		 * If non-contiguous masks ever become important
367		 * we can restore the masking and open coding of
368		 * the search and satisfaction test and put the
369		 * calculation of "off" back before the "do".
370		 */
371		while (m) {
372			if (m->rm_flags & RNF_NORMAL) {
373				if ((rn_bit <= m->rm_bit) &&
374				    RN_MATCHF(m->rm_leaf, f, w))
375					return (m->rm_leaf);
376			} else {
377				off = min(t->rn_offset, matched_off);
378				x = rn_search_m(v, t, m->rm_mask);
379				while (x && x->rn_mask != m->rm_mask)
380					x = x->rn_dupedkey;
381				if (x && rn_satisfies_leaf(v, x, off, f, w))
382					return (x);
383			}
384			m = m->rm_mklist;
385		}
386	} while (t != top);
387	return (NULL);
388}
389
390#ifdef RN_DEBUG
391int	rn_nodenum;
392struct	radix_node *rn_clist;
393int	rn_saveinfo;
394int	rn_debug =  1;
395#endif
396
397static struct radix_node *
398rn_newpair(void *v, int b, struct radix_node nodes[2])
399{
400	struct radix_node *tt = nodes, *t = tt + 1;
401	t->rn_bit = b;
402	t->rn_bmask = 0x80 >> (b & 7);
403	t->rn_left = tt;
404	t->rn_offset = b >> 3;
405	tt->rn_bit = -1;
406	tt->rn_key = (caddr_t)v;
407	tt->rn_parent = t;
408	tt->rn_flags = t->rn_flags = RNF_ACTIVE;
409	tt->rn_mklist = t->rn_mklist = NULL;
410#ifdef RN_DEBUG
411	tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
412	tt->rn_twin = t;
413	tt->rn_ybro = rn_clist;
414	rn_clist = tt;
415#endif
416	return t;
417}
418
419static struct radix_node *
420rn_insert(void *v_arg, struct radix_node_head *head, int *dupentry,
421	  struct radix_node nodes[2])
422{
423	caddr_t v = v_arg;
424	struct radix_node *top = head->rnh_treetop;
425	int head_off = top->rn_offset, vlen = (int)*((u_char *)v);
426	struct radix_node *t = rn_search(v_arg, top);
427	caddr_t cp = v + head_off;
428	int b;
429	struct radix_node *tt;
430    	/*
431	 * Find first bit at which v and t->rn_key differ
432	 */
433    {
434	caddr_t cp2 = t->rn_key + head_off;
435	int cmp_res;
436	caddr_t cplim = v + vlen;
437
438	while (cp < cplim)
439		if (*cp2++ != *cp++)
440			goto on1;
441	*dupentry = 1;
442	return t;
443on1:
444	*dupentry = 0;
445	cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
446	for (b = (cp - v) << 3; cmp_res; b--)
447		cmp_res >>= 1;
448    }
449    {
450	struct radix_node *p, *x = top;
451	cp = v;
452	do {
453		p = x;
454		if (cp[x->rn_offset] & x->rn_bmask)
455			x = x->rn_right;
456		else
457			x = x->rn_left;
458	} while (b > (unsigned) x->rn_bit);
459				/* x->rn_bit < b && x->rn_bit >= 0 */
460#ifdef RN_DEBUG
461	if (rn_debug)
462		log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p);
463#endif
464	t = rn_newpair(v_arg, b, nodes);
465	tt = t->rn_left;
466	if ((cp[p->rn_offset] & p->rn_bmask) == 0)
467		p->rn_left = t;
468	else
469		p->rn_right = t;
470	x->rn_parent = t;
471	t->rn_parent = p; /* frees x, p as temp vars below */
472	if ((cp[t->rn_offset] & t->rn_bmask) == 0) {
473		t->rn_right = x;
474	} else {
475		t->rn_right = tt;
476		t->rn_left = x;
477	}
478#ifdef RN_DEBUG
479	if (rn_debug)
480		log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
481#endif
482    }
483	return (tt);
484}
485
486struct radix_node *
487rn_addmask(void *n_arg, int search, int skip)
488{
489	caddr_t netmask = (caddr_t)n_arg;
490	struct radix_node *x;
491	caddr_t cp, cplim;
492	int b = 0, mlen, j;
493	int maskduplicated, m0, isnormal;
494	struct radix_node *saved_x;
495	static int last_zeroed = 0;
496
497	if ((mlen = *(u_char *)netmask) > max_keylen)
498		mlen = max_keylen;
499	if (skip == 0)
500		skip = 1;
501	if (mlen <= skip)
502		return (mask_rnhead->rnh_nodes);
503	if (skip > 1)
504		Bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
505	if ((m0 = mlen) > skip)
506		Bcopy(netmask + skip, addmask_key + skip, mlen - skip);
507	/*
508	 * Trim trailing zeroes.
509	 */
510	for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
511		cp--;
512	mlen = cp - addmask_key;
513	if (mlen <= skip) {
514		if (m0 >= last_zeroed)
515			last_zeroed = mlen;
516		return (mask_rnhead->rnh_nodes);
517	}
518	if (m0 < last_zeroed)
519		Bzero(addmask_key + m0, last_zeroed - m0);
520	*addmask_key = last_zeroed = mlen;
521	x = rn_search(addmask_key, rn_masktop);
522	if (Bcmp(addmask_key, x->rn_key, mlen) != 0)
523		x = NULL;
524	if (x || search)
525		return (x);
526	R_Malloc(x, struct radix_node *, max_keylen + 2 * sizeof (*x));
527	if ((saved_x = x) == 0)
528		return (NULL);
529	Bzero(x, max_keylen + 2 * sizeof (*x));
530	netmask = cp = (caddr_t)(x + 2);
531	Bcopy(addmask_key, cp, mlen);
532	x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
533	if (maskduplicated) {
534		log(LOG_ERR, "rn_addmask: mask impossibly already in tree");
535		R_Free(saved_x);
536		return (x);
537	}
538	mask_rnhead->rnh_cnt++;
539	/*
540	 * Calculate index of mask, and check for normalcy.
541	 */
542	cplim = netmask + mlen; isnormal = 1;
543	for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
544		cp++;
545	if (cp != cplim) {
546		for (j = 0x80; (j & *cp) != 0; j >>= 1)
547			b++;
548		if (*cp != normal_chars[b] || cp != (cplim - 1))
549			isnormal = 0;
550	}
551	b += (cp - netmask) << 3;
552	x->rn_bit = -1 - b;
553	if (isnormal)
554		x->rn_flags |= RNF_NORMAL;
555	return (x);
556}
557
558static int	/* XXX: arbitrary ordering for non-contiguous masks */
559rn_lexobetter(void *m_arg, void *n_arg)
560{
561	u_char *mp = m_arg, *np = n_arg, *lim;
562
563	if (*mp > *np)
564		return 1;  /* not really, but need to check longer one first */
565	if (*mp == *np)
566		for (lim = mp + *mp; mp < lim;)
567			if (*mp++ > *np++)
568				return 1;
569	return 0;
570}
571
572static struct radix_mask *
573rn_new_radix_mask(struct radix_node *tt, struct radix_mask *next)
574{
575	struct radix_mask *m;
576
577	MKGet(m);
578	if (m == 0) {
579		log(LOG_ERR, "Mask for route not entered\n");
580		return (NULL);
581	}
582	Bzero(m, sizeof *m);
583	m->rm_bit = tt->rn_bit;
584	m->rm_flags = tt->rn_flags;
585	if (tt->rn_flags & RNF_NORMAL)
586		m->rm_leaf = tt;
587	else
588		m->rm_mask = tt->rn_mask;
589	m->rm_mklist = next;
590	tt->rn_mklist = m;
591	return m;
592}
593
594struct radix_node *
595rn_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
596	    struct radix_node treenodes[2])
597{
598	caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
599	struct radix_node *t, *x = NULL, *tt;
600	struct radix_node *saved_tt, *top = head->rnh_treetop;
601	short b = 0, b_leaf = 0;
602	int keyduplicated;
603	caddr_t mmask;
604	struct radix_mask *m, **mp;
605
606	/*
607	 * In dealing with non-contiguous masks, there may be
608	 * many different routes which have the same mask.
609	 * We will find it useful to have a unique pointer to
610	 * the mask to speed avoiding duplicate references at
611	 * nodes and possibly save time in calculating indices.
612	 */
613	if (netmask)  {
614		if ((x = rn_addmask(netmask, 0, top->rn_offset)) == 0)
615			return (NULL);
616		b_leaf = x->rn_bit;
617		b = -1 - x->rn_bit;
618		netmask = x->rn_key;
619	}
620	/*
621	 * Deal with duplicated keys: attach node to previous instance
622	 */
623	saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
624	if (keyduplicated) {
625		for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
626			if (tt->rn_mask == netmask)
627				return (NULL);
628			if (netmask == 0 ||
629			    (tt->rn_mask &&
630			     ((b_leaf < tt->rn_bit) /* index(netmask) > node */
631			      || rn_refines(netmask, tt->rn_mask)
632			      || rn_lexobetter(netmask, tt->rn_mask))))
633				break;
634		}
635		/*
636		 * If the mask is not duplicated, we wouldn't
637		 * find it among possible duplicate key entries
638		 * anyway, so the above test doesn't hurt.
639		 *
640		 * We sort the masks for a duplicated key the same way as
641		 * in a masklist -- most specific to least specific.
642		 * This may require the unfortunate nuisance of relocating
643		 * the head of the list.
644		 */
645		if (tt == saved_tt) {
646			struct	radix_node *xx = x;
647			/* link in at head of list */
648			(tt = treenodes)->rn_dupedkey = t;
649			tt->rn_flags = t->rn_flags;
650			tt->rn_parent = x = t->rn_parent;
651			t->rn_parent = tt;	 		/* parent */
652			if (x->rn_left == t)
653				x->rn_left = tt;
654			else
655				x->rn_right = tt;
656			saved_tt = tt; x = xx;
657		} else {
658			(tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
659			t->rn_dupedkey = tt;
660			tt->rn_parent = t;			/* parent */
661			if (tt->rn_dupedkey)			/* parent */
662				tt->rn_dupedkey->rn_parent = tt; /* parent */
663		}
664#ifdef RN_DEBUG
665		t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
666		tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
667#endif
668		tt->rn_key = (caddr_t) v;
669		tt->rn_bit = -1;
670		tt->rn_flags = RNF_ACTIVE;
671	}
672	head->rnh_cnt++;
673	/*
674	 * Put mask in tree.
675	 */
676	if (netmask) {
677		tt->rn_mask = netmask;
678		tt->rn_bit = x->rn_bit;
679		tt->rn_flags |= x->rn_flags & RNF_NORMAL;
680	}
681	t = saved_tt->rn_parent;
682	if (keyduplicated)
683		goto on2;
684	b_leaf = -1 - t->rn_bit;
685	if (t->rn_right == saved_tt)
686		x = t->rn_left;
687	else
688		x = t->rn_right;
689	/* Promote general routes from below */
690	if (x->rn_bit < 0) {
691	    for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
692		if (x->rn_mask && (x->rn_bit >= b_leaf) && x->rn_mklist == 0) {
693			*mp = m = rn_new_radix_mask(x, NULL);
694			if (m)
695				mp = &m->rm_mklist;
696		}
697	} else if (x->rn_mklist) {
698		/*
699		 * Skip over masks whose index is > that of new node
700		 */
701		for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
702			if (m->rm_bit >= b_leaf)
703				break;
704		t->rn_mklist = m; *mp = NULL;
705	}
706on2:
707	/* Add new route to highest possible ancestor's list */
708	if ((netmask == 0) || (b > t->rn_bit ))
709		return tt; /* can't lift at all */
710	b_leaf = tt->rn_bit;
711	do {
712		x = t;
713		t = t->rn_parent;
714	} while (b <= t->rn_bit && x != top);
715	/*
716	 * Search through routes associated with node to
717	 * insert new route according to index.
718	 * Need same criteria as when sorting dupedkeys to avoid
719	 * double loop on deletion.
720	 */
721	for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
722		if (m->rm_bit < b_leaf)
723			continue;
724		if (m->rm_bit > b_leaf)
725			break;
726		if (m->rm_flags & RNF_NORMAL) {
727			mmask = m->rm_leaf->rn_mask;
728			if (tt->rn_flags & RNF_NORMAL) {
729			    log(LOG_ERR,
730			        "Non-unique normal route, mask not entered");
731				return tt;
732			}
733		} else
734			mmask = m->rm_mask;
735		if (mmask == netmask) {
736			m->rm_refs++;
737			tt->rn_mklist = m;
738			return tt;
739		}
740		if (rn_refines(netmask, mmask)
741		    || rn_lexobetter(netmask, mmask))
742			break;
743	}
744	*mp = rn_new_radix_mask(tt, *mp);
745	return tt;
746}
747
748struct radix_node *
749rn_delete(void *v_arg, void *netmask_arg, struct radix_node_head *head)
750{
751	struct radix_node *t, *p, *x, *tt;
752	struct radix_mask *m, *saved_m, **mp;
753	struct radix_node *dupedkey, *saved_tt, *top;
754	caddr_t v, netmask;
755	int b, head_off, vlen;
756
757	v = v_arg;
758	netmask = netmask_arg;
759	x = head->rnh_treetop;
760	tt = rn_search(v, x);
761	head_off = x->rn_offset;
762	vlen =  *(u_char *)v;
763	saved_tt = tt;
764	top = x;
765	if (tt == 0 ||
766	    Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
767		return (NULL);
768	/*
769	 * Delete our route from mask lists.
770	 */
771	if (netmask) {
772		if ((x = rn_addmask(netmask, 1, head_off)) == 0)
773			return (NULL);
774		netmask = x->rn_key;
775		while (tt->rn_mask != netmask)
776			if ((tt = tt->rn_dupedkey) == 0)
777				return (NULL);
778	}
779	if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
780		goto on1;
781	if (tt->rn_flags & RNF_NORMAL) {
782		if (m->rm_leaf != tt || m->rm_refs > 0) {
783			log(LOG_ERR, "rn_delete: inconsistent annotation\n");
784			return NULL;  /* dangling ref could cause disaster */
785		}
786	} else {
787		if (m->rm_mask != tt->rn_mask) {
788			log(LOG_ERR, "rn_delete: inconsistent annotation\n");
789			goto on1;
790		}
791		if (--m->rm_refs >= 0)
792			goto on1;
793	}
794	b = -1 - tt->rn_bit;
795	t = saved_tt->rn_parent;
796	if (b > t->rn_bit)
797		goto on1; /* Wasn't lifted at all */
798	do {
799		x = t;
800		t = t->rn_parent;
801	} while (b <= t->rn_bit && x != top);
802	for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
803		if (m == saved_m) {
804			*mp = m->rm_mklist;
805			MKFree(m);
806			break;
807		}
808	if (m == 0) {
809		log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
810		if (tt->rn_flags & RNF_NORMAL)
811			return (NULL); /* Dangling ref to us */
812	}
813on1:
814	/*
815	 * Eliminate us from tree
816	 */
817	if (tt->rn_flags & RNF_ROOT)
818		return (NULL);
819	head->rnh_cnt--;
820#ifdef RN_DEBUG
821	/* Get us out of the creation list */
822	for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
823	if (t) t->rn_ybro = tt->rn_ybro;
824#endif
825	t = tt->rn_parent;
826	dupedkey = saved_tt->rn_dupedkey;
827	if (dupedkey) {
828		/*
829		 * at this point, tt is the deletion target and saved_tt
830		 * is the head of the dupekey chain
831		 */
832		if (tt == saved_tt) {
833			/* remove from head of chain */
834			x = dupedkey; x->rn_parent = t;
835			if (t->rn_left == tt)
836				t->rn_left = x;
837			else
838				t->rn_right = x;
839		} else {
840			/* find node in front of tt on the chain */
841			for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
842				p = p->rn_dupedkey;
843			if (p) {
844				p->rn_dupedkey = tt->rn_dupedkey;
845				if (tt->rn_dupedkey)		/* parent */
846					tt->rn_dupedkey->rn_parent = p;
847								/* parent */
848			} else log(LOG_ERR, "rn_delete: couldn't find us\n");
849		}
850		t = tt + 1;
851		if  (t->rn_flags & RNF_ACTIVE) {
852#ifndef RN_DEBUG
853			*++x = *t;
854			p = t->rn_parent;
855#else
856			b = t->rn_info;
857			*++x = *t;
858			t->rn_info = b;
859			p = t->rn_parent;
860#endif
861			if (p->rn_left == t)
862				p->rn_left = x;
863			else
864				p->rn_right = x;
865			x->rn_left->rn_parent = x;
866			x->rn_right->rn_parent = x;
867		}
868		goto out;
869	}
870	if (t->rn_left == tt)
871		x = t->rn_right;
872	else
873		x = t->rn_left;
874	p = t->rn_parent;
875	if (p->rn_right == t)
876		p->rn_right = x;
877	else
878		p->rn_left = x;
879	x->rn_parent = p;
880	/*
881	 * Demote routes attached to us.
882	 */
883	if (t->rn_mklist) {
884		if (x->rn_bit >= 0) {
885			for (mp = &x->rn_mklist; (m = *mp);)
886				mp = &m->rm_mklist;
887			*mp = t->rn_mklist;
888		} else {
889			/* If there are any key,mask pairs in a sibling
890			   duped-key chain, some subset will appear sorted
891			   in the same order attached to our mklist */
892			for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
893				if (m == x->rn_mklist) {
894					struct radix_mask *mm = m->rm_mklist;
895					x->rn_mklist = NULL;
896					if (--(m->rm_refs) < 0)
897						MKFree(m);
898					m = mm;
899				}
900			if (m)
901				log(LOG_ERR,
902				    "rn_delete: Orphaned Mask %p at %p\n",
903				    (void *)m, (void *)x);
904		}
905	}
906	/*
907	 * We may be holding an active internal node in the tree.
908	 */
909	x = tt + 1;
910	if (t != x) {
911#ifndef RN_DEBUG
912		*t = *x;
913#else
914		b = t->rn_info;
915		*t = *x;
916		t->rn_info = b;
917#endif
918		t->rn_left->rn_parent = t;
919		t->rn_right->rn_parent = t;
920		p = x->rn_parent;
921		if (p->rn_left == x)
922			p->rn_left = t;
923		else
924			p->rn_right = t;
925	}
926out:
927	tt->rn_flags &= ~RNF_ACTIVE;
928	tt[1].rn_flags &= ~RNF_ACTIVE;
929	return (tt);
930}
931
932/*
933 * This is the same as rn_walktree() except for the parameters and the
934 * exit.
935 */
936static int
937rn_walktree_from(struct radix_node_head *h, void *a, void *m, walktree_f_t *f,
938    void *w)
939{
940	int error;
941	struct radix_node *base, *next;
942	u_char *xa = (u_char *)a;
943	u_char *xm = (u_char *)m;
944	struct radix_node *rn, *last;
945	int stopping;
946	int lastb;
947	int rnh_cnt;
948
949	/*
950	 * This gets complicated because we may delete the node while
951	 * applying the function f to it; we cannot simply use the next
952	 * leaf as the successor node in advance, because that leaf may
953	 * be removed as well during deletion when it is a clone of the
954	 * current node.  When that happens, we would end up referring
955	 * to an already-freed radix node as the successor node.  To get
956	 * around this issue, if we detect that the radix tree has changed
957	 * in dimension (smaller than before), we simply restart the walk
958	 * from the top of tree.
959	 */
960restart:
961	last = NULL;
962	stopping = 0;
963	rnh_cnt = h->rnh_cnt;
964
965	/*
966	 * rn_search_m is sort-of-open-coded here.
967	 */
968	for (rn = h->rnh_treetop; rn->rn_bit >= 0; ) {
969		last = rn;
970		if (!(rn->rn_bmask & xm[rn->rn_offset]))
971			break;
972
973		if (rn->rn_bmask & xa[rn->rn_offset])
974			rn = rn->rn_right;
975		else
976			rn = rn->rn_left;
977	}
978
979	/*
980	 * Two cases: either we stepped off the end of our mask,
981	 * in which case last == rn, or we reached a leaf, in which
982	 * case we want to start from the last node we looked at.
983	 * Either way, last is the node we want to start from.
984	 */
985	rn = last;
986	lastb = rn->rn_bit;
987
988	/* First time through node, go left */
989	while (rn->rn_bit >= 0)
990		rn = rn->rn_left;
991
992	while (!stopping) {
993		base = rn;
994		/* If at right child go back up, otherwise, go right */
995		while (rn->rn_parent->rn_right == rn
996		       && !(rn->rn_flags & RNF_ROOT)) {
997			rn = rn->rn_parent;
998
999			/* if went up beyond last, stop */
1000			if (rn->rn_bit <= lastb) {
1001				stopping = 1;
1002				/*
1003				 * XXX we should jump to the 'Process leaves'
1004				 * part, because the values of 'rn' and 'next'
1005				 * we compute will not be used. Not a big deal
1006				 * because this loop will terminate, but it is
1007				 * inefficient and hard to understand!
1008				 */
1009			}
1010		}
1011
1012		/*
1013		 * The following code (bug fix) inherited from FreeBSD is
1014		 * currently disabled, because our implementation uses the
1015		 * RTF_PRCLONING scheme that has been abandoned in current
1016		 * FreeBSD release.  The scheme involves setting such a flag
1017		 * for the default route entry, and therefore all off-link
1018		 * destinations would become clones of that entry.  Enabling
1019		 * the following code would be problematic at this point,
1020		 * because the removal of default route would cause only
1021		 * the left-half of the tree to be traversed, leaving the
1022		 * right-half untouched.  If there are clones of the entry
1023		 * that reside in that right-half, they would not be deleted
1024		 * and would linger around until they expire or explicitly
1025		 * deleted, which is a very bad thing.
1026		 *
1027		 * This code should be uncommented only after we get rid
1028		 * of the RTF_PRCLONING scheme.
1029		 */
1030#if 0
1031		/*
1032		 * At the top of the tree, no need to traverse the right
1033		 * half, prevent the traversal of the entire tree in the
1034		 * case of default route.
1035		 */
1036		if (rn->rn_parent->rn_flags & RNF_ROOT)
1037			stopping = 1;
1038#endif
1039
1040		/* Find the next *leaf* to start from */
1041		for (rn = rn->rn_parent->rn_right; rn->rn_bit >= 0;)
1042			rn = rn->rn_left;
1043		next = rn;
1044		/* Process leaves */
1045		while ((rn = base) != 0) {
1046			base = rn->rn_dupedkey;
1047			if (!(rn->rn_flags & RNF_ROOT)
1048			    && (error = (*f)(rn, w)))
1049				return (error);
1050		}
1051		/* If one or more nodes got deleted, restart from top */
1052		if (h->rnh_cnt < rnh_cnt)
1053			goto restart;
1054		rn = next;
1055		if (rn->rn_flags & RNF_ROOT)
1056			stopping = 1;
1057	}
1058	return 0;
1059}
1060
1061static int
1062rn_walktree(struct radix_node_head *h, walktree_f_t *f, void *w)
1063{
1064	int error;
1065	struct radix_node *base, *next;
1066	struct radix_node *rn;
1067	int rnh_cnt;
1068
1069	/*
1070	 * This gets complicated because we may delete the node while
1071	 * applying the function f to it; we cannot simply use the next
1072	 * leaf as the successor node in advance, because that leaf may
1073	 * be removed as well during deletion when it is a clone of the
1074	 * current node.  When that happens, we would end up referring
1075	 * to an already-freed radix node as the successor node.  To get
1076	 * around this issue, if we detect that the radix tree has changed
1077	 * in dimension (smaller than before), we simply restart the walk
1078	 * from the top of tree.
1079	 */
1080restart:
1081	rn = h->rnh_treetop;
1082	rnh_cnt = h->rnh_cnt;
1083
1084	/* First time through node, go left */
1085	while (rn->rn_bit >= 0)
1086		rn = rn->rn_left;
1087	for (;;) {
1088		base = rn;
1089		/* If at right child go back up, otherwise, go right */
1090		while (rn->rn_parent->rn_right == rn &&
1091		    (rn->rn_flags & RNF_ROOT) == 0)
1092			rn = rn->rn_parent;
1093		/* Find the next *leaf* to start from */
1094		for (rn = rn->rn_parent->rn_right; rn->rn_bit >= 0;)
1095			rn = rn->rn_left;
1096		next = rn;
1097		/* Process leaves */
1098		while ((rn = base) != NULL) {
1099			base = rn->rn_dupedkey;
1100			if (!(rn->rn_flags & RNF_ROOT)
1101			    && (error = (*f)(rn, w)))
1102				return (error);
1103		}
1104		/* If one or more nodes got deleted, restart from top */
1105		if (h->rnh_cnt < rnh_cnt)
1106			goto restart;
1107		rn = next;
1108		if (rn->rn_flags & RNF_ROOT)
1109			return (0);
1110	}
1111	/* NOTREACHED */
1112}
1113
1114int
1115rn_inithead(void **head, int off)
1116{
1117	struct radix_node_head *rnh;
1118	struct radix_node *t, *tt, *ttt;
1119	if (*head)
1120		return (1);
1121	R_Malloc(rnh, struct radix_node_head *, sizeof (*rnh));
1122	if (rnh == 0)
1123		return (0);
1124	Bzero(rnh, sizeof (*rnh));
1125	*head = rnh;
1126	t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
1127	ttt = rnh->rnh_nodes + 2;
1128	t->rn_right = ttt;
1129	t->rn_parent = t;
1130	tt = t->rn_left;
1131	tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
1132	tt->rn_bit = -1 - off;
1133	*ttt = *tt;
1134	ttt->rn_key = rn_ones;
1135	rnh->rnh_addaddr = rn_addroute;
1136	rnh->rnh_deladdr = rn_delete;
1137	rnh->rnh_matchaddr = rn_match;
1138	rnh->rnh_matchaddr_args = rn_match_args;
1139	rnh->rnh_lookup = rn_lookup;
1140	rnh->rnh_lookup_args = rn_lookup_args;
1141	rnh->rnh_walktree = rn_walktree;
1142	rnh->rnh_walktree_from = rn_walktree_from;
1143	rnh->rnh_treetop = t;
1144	rnh->rnh_cnt = 3;
1145	return (1);
1146}
1147
1148void
1149rn_init(void)
1150{
1151	char *cp, *cplim;
1152#ifdef KERNEL
1153	struct domain *dom;
1154
1155	/* lock already held when rn_init is called */
1156	for (dom = domains; dom; dom = dom->dom_next)
1157		if (dom->dom_maxrtkey > max_keylen)
1158			max_keylen = dom->dom_maxrtkey;
1159#endif
1160	if (max_keylen == 0) {
1161		log(LOG_ERR,
1162		    "rn_init: radix functions require max_keylen be set\n");
1163		return;
1164	}
1165	R_Malloc(rn_zeros, char *, 3 * max_keylen);
1166	if (rn_zeros == NULL)
1167		panic("rn_init");
1168	Bzero(rn_zeros, 3 * max_keylen);
1169	rn_ones = cp = rn_zeros + max_keylen;
1170	addmask_key = cplim = rn_ones + max_keylen;
1171	while (cp < cplim)
1172		*cp++ = -1;
1173	if (rn_inithead((void **)&mask_rnhead, 0) == 0)
1174		panic("rn_init 2");
1175}
1176