2 * Copyright (c) 1988, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)radix.c 8.4 (Berkeley) 11/2/94
31 * $FreeBSD: src/sbin/routed/radix.c,v 1.5 1999/09/05 17:49:11 peter Exp $
35 * Routines to build and maintain radix trees for routing lookups.
40 #if !defined(sgi) && !defined(__NetBSD__)
41 static char sccsid[] __attribute__((unused)) = "@(#)rdisc.c 8.1 (Berkeley) x/y/95";
42 #elif defined(__NetBSD__)
46 #define log(x, msg) syslog(x, msg)
47 #define panic(s) {log(LOG_ERR,s); exit(1);}
48 #define min(a,b) (((a)<(b))?(a):(b))
51 struct radix_mask *rn_mkfreelist;
52 struct radix_node_head *mask_rnhead;
53 static char *addmask_key;
54 static char normal_chars[] = {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
55 static char *rn_zeros, *rn_ones;
57 #define rn_masktop (mask_rnhead->rnh_treetop)
59 #define Bcmp(a, b, l) (l == 0 ? 0 \
60 : memcmp((caddr_t)(a), (caddr_t)(b), (size_t)l))
62 static int rn_satisfies_leaf(char *, struct radix_node *, int);
65 * The data structure for the keys is a radix tree with one way
66 * branching removed. The index rn_b at an internal node n represents a bit
67 * position to be tested. The tree is arranged so that all descendants
68 * of a node n have keys whose bits all agree up to position rn_b - 1.
69 * (We say the index of n is rn_b.)
71 * There is at least one descendant which has a one bit at position rn_b,
72 * and at least one with a zero there.
74 * A route is determined by a pair of key and mask. We require that the
75 * bit-wise logical and of the key and mask to be the key.
76 * We define the index of a route to associated with the mask to be
77 * the first bit number in the mask where 0 occurs (with bit number 0
78 * representing the highest order bit).
80 * We say a mask is normal if every bit is 0, past the index of the mask.
81 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
82 * and m is a normal mask, then the route applies to every descendant of n.
83 * If the index(m) < rn_b, this implies the trailing last few bits of k
84 * before bit b are all 0, (and hence consequently true of every descendant
85 * of n), so the route applies to all descendants of the node as well.
87 * Similar logic shows that a non-normal mask m such that
88 * index(m) <= index(n) could potentially apply to many children of n.
89 * Thus, for each non-host route, we attach its mask to a list at an internal
90 * node as high in the tree as we can go.
92 * The present version of the code makes use of normal routes in short-
93 * circuiting an explict mask and compare operation when testing whether
94 * a key satisfies a normal route, and also in remembering the unique leaf
95 * that governs a subtree.
99 rn_search(void *v_arg,
100 struct radix_node *head)
102 struct radix_node *x;
105 for (x = head, v = v_arg; x->rn_b >= 0;) {
106 if (x->rn_bmask & v[x->rn_off])
115 rn_search_m(void *v_arg,
116 struct radix_node *head,
119 struct radix_node *x;
120 caddr_t v = v_arg, m = m_arg;
122 for (x = head; x->rn_b >= 0;) {
123 if ((x->rn_bmask & m[x->rn_off]) &&
124 (x->rn_bmask & v[x->rn_off]))
133 rn_refines(void* m_arg, void *n_arg)
135 caddr_t m = m_arg, n = n_arg;
136 caddr_t lim, lim2 = lim = n + *(u_char *)n;
137 int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
138 int masks_are_equal = 1;
151 if (masks_are_equal && (longer < 0))
152 for (lim2 = m - longer; m < lim2; )
155 return (!masks_are_equal);
159 rn_lookup(void *v_arg, void *m_arg, struct radix_node_head *head)
161 struct radix_node *x;
165 if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == NULL)
169 x = rn_match(v_arg, head);
171 while (x && x->rn_mask != netmask)
178 rn_satisfies_leaf(char *trial,
179 struct radix_node *leaf,
182 char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
184 int length = min(*(u_char *)cp, *(u_char *)cp2);
189 length = min(length, *(u_char *)cp3);
190 cplim = cp + length; cp3 += skip; cp2 += skip;
191 for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
192 if ((*cp ^ *cp2) & *cp3)
198 rn_match(void *v_arg,
199 struct radix_node_head *head)
202 struct radix_node *t = head->rnh_treetop, *x;
205 struct radix_node *saved_t, *top = t;
206 int off = t->rn_off, vlen = *(u_char *)cp, matched_off;
210 * Open code rn_search(v, top) to avoid overhead of extra
213 for (; t->rn_b >= 0; ) {
214 if (t->rn_bmask & cp[t->rn_off])
220 * See if we match exactly as a host destination
221 * or at least learn how many bits match, for normal mask finesse.
223 * It doesn't hurt us to limit how many bytes to check
224 * to the length of the mask, since if it matches we had a genuine
225 * match and the leaf we have is the most specific one anyway;
226 * if it didn't match with a shorter length it would fail
227 * with a long one. This wins big for class B&C netmasks which
228 * are probably the most common case...
231 vlen = *(u_char *)t->rn_mask;
232 cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
233 for (; cp < cplim; cp++, cp2++)
237 * This extra grot is in case we are explicitly asked
238 * to look up the default. Ugh!
241 * In this case, we have a complete match of the key. Unless
242 * the node is one of the roots, we are finished.
243 * If it is the zeros root, then take what we have, prefering
245 * If it is the ones root, then pretend the target key was followed
246 * by a byte of zeros.
248 if (!(t->rn_flags & RNF_ROOT))
249 return t; /* not a root */
250 if (t->rn_dupedkey) {
252 return t; /* have some real data */
255 return t; /* not the ones root */
256 b = 0; /* fake a zero after 255.255.255.255 */
259 test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
260 for (b = 7; (test >>= 1) > 0;)
263 matched_off = cp - v;
264 b += matched_off << 3;
267 * If there is a host route in a duped-key chain, it will be first.
269 if ((saved_t = t)->rn_mask == 0)
271 for (; t; t = t->rn_dupedkey) {
273 * Even if we don't match exactly as a host,
274 * we may match if the leaf we wound up at is
277 if (t->rn_flags & RNF_NORMAL) {
280 } else if (rn_satisfies_leaf(v, t, matched_off)) {
285 /* start searching up the tree */
287 struct radix_mask *m;
289 if ((m = t->rn_mklist)) {
291 * If non-contiguous masks ever become important
292 * we can restore the masking and open coding of
293 * the search and satisfaction test and put the
294 * calculation of "off" back before the "do".
297 if (m->rm_flags & RNF_NORMAL) {
301 off = min(t->rn_off, matched_off);
302 x = rn_search_m(v, t, m->rm_mask);
303 while (x && x->rn_mask != m->rm_mask)
305 if (x && rn_satisfies_leaf(v, x, off))
308 } while ((m = m->rm_mklist));
316 struct radix_node *rn_clist;
322 rn_newpair(void *v, int b, struct radix_node nodes[2])
324 struct radix_node *tt = nodes, *t = tt + 1;
325 t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7);
326 t->rn_l = tt; t->rn_off = b >> 3;
327 tt->rn_b = -1; tt->rn_key = (caddr_t)v; tt->rn_p = t;
328 tt->rn_flags = t->rn_flags = RNF_ACTIVE;
330 tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
331 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
337 rn_insert(void* v_arg,
338 struct radix_node_head *head,
340 struct radix_node nodes[2])
343 struct radix_node *top = head->rnh_treetop;
344 int head_off = top->rn_off, vlen = (int)*((u_char *)v);
345 struct radix_node *t = rn_search(v_arg, top);
346 caddr_t cp = v + head_off;
348 struct radix_node *tt;
351 * Find first bit at which v and t->rn_key differ
354 caddr_t cp2 = t->rn_key + head_off;
356 caddr_t cplim = v + vlen;
361 /* handle adding 255.255.255.255 */
362 if (!(t->rn_flags & RNF_ROOT) || *(cp2-1) == 0) {
368 cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
369 for (b = (cp - v) << 3; cmp_res; b--)
373 struct radix_node *p, *x = top;
377 if (cp[x->rn_off] & x->rn_bmask)
380 } while ((unsigned)b > (unsigned)x->rn_b);
383 log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p);
385 t = rn_newpair(v_arg, b, nodes); tt = t->rn_l;
386 if ((cp[p->rn_off] & p->rn_bmask) == 0)
390 x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */
391 if ((cp[t->rn_off] & t->rn_bmask) == 0) {
394 t->rn_r = tt; t->rn_l = x;
398 log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
405 rn_addmask(void *n_arg, int search, int skip)
407 caddr_t netmask = (caddr_t)n_arg;
408 struct radix_node *x;
411 int maskduplicated, m0, isnormal;
412 struct radix_node *saved_x;
413 static int last_zeroed = 0;
415 if ((mlen = *(u_char *)netmask) > max_keylen)
420 return (mask_rnhead->rnh_nodes);
422 Bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
423 if ((m0 = mlen) > skip)
424 Bcopy(netmask + skip, addmask_key + skip, mlen - skip);
426 * Trim trailing zeroes.
428 for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
430 mlen = cp - addmask_key;
432 if (m0 >= last_zeroed)
434 return (mask_rnhead->rnh_nodes);
436 if (m0 < last_zeroed)
437 Bzero(addmask_key + m0, last_zeroed - m0);
438 *addmask_key = last_zeroed = mlen;
439 x = rn_search(addmask_key, rn_masktop);
440 if (Bcmp(addmask_key, x->rn_key, mlen) != 0)
444 x = (struct radix_node *)rtmalloc(max_keylen + 2*sizeof(*x),
447 Bzero(x, max_keylen + 2 * sizeof (*x));
448 netmask = cp = (caddr_t)(x + 2);
449 Bcopy(addmask_key, cp, mlen);
450 x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
451 if (maskduplicated) {
452 log(LOG_ERR, "rn_addmask: mask impossibly already in tree");
457 * Calculate index of mask, and check for normalcy.
459 cplim = netmask + mlen; isnormal = 1;
460 for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
463 for (j = 0x80; (j & *cp) != 0; j >>= 1)
465 if (*cp != normal_chars[b] || cp != (cplim - 1))
468 b += (cp - netmask) << 3;
471 x->rn_flags |= RNF_NORMAL;
475 static int /* XXX: arbitrary ordering for non-contiguous masks */
476 rn_lexobetter(void *m_arg, void *n_arg)
478 u_char *mp = m_arg, *np = n_arg, *lim;
481 return 1; /* not really, but need to check longer one first */
483 for (lim = mp + *mp; mp < lim;)
489 static struct radix_mask *
490 rn_new_radix_mask(struct radix_node *tt,
491 struct radix_mask *next)
493 struct radix_mask *m;
497 log(LOG_ERR, "Mask for route not entered\n");
502 m->rm_flags = tt->rn_flags;
503 if (tt->rn_flags & RNF_NORMAL)
506 m->rm_mask = tt->rn_mask;
513 rn_addroute(void *v_arg,
515 struct radix_node_head *head,
516 struct radix_node treenodes[2])
518 caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
519 struct radix_node *t, *x = NULL, *tt;
520 struct radix_node *saved_tt, *top = head->rnh_treetop;
521 short b = 0, b_leaf = 0;
524 struct radix_mask *m, **mp;
527 * In dealing with non-contiguous masks, there may be
528 * many different routes which have the same mask.
529 * We will find it useful to have a unique pointer to
530 * the mask to speed avoiding duplicate references at
531 * nodes and possibly save time in calculating indices.
534 if ((x = rn_addmask(netmask, 0, top->rn_off)) == NULL)
541 * Deal with duplicated keys: attach node to previous instance
543 saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
545 for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
546 if (tt->rn_mask == netmask)
550 ((b_leaf < tt->rn_b) || /* index(netmask) > node */
551 rn_refines(netmask, tt->rn_mask) ||
552 rn_lexobetter(netmask, tt->rn_mask))))
556 * If the mask is not duplicated, we wouldn't
557 * find it among possible duplicate key entries
558 * anyway, so the above test doesn't hurt.
560 * We sort the masks for a duplicated key the same way as
561 * in a masklist -- most specific to least specific.
562 * This may require the unfortunate nuisance of relocating
563 * the head of the list.
565 if (tt == saved_tt) {
566 struct radix_node *xx = x;
567 /* link in at head of list */
568 (tt = treenodes)->rn_dupedkey = t;
569 tt->rn_flags = t->rn_flags;
570 tt->rn_p = x = t->rn_p;
571 if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt;
572 saved_tt = tt; x = xx;
574 (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
578 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
579 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
581 tt->rn_key = (caddr_t) v;
583 tt->rn_flags = RNF_ACTIVE;
589 tt->rn_mask = netmask;
591 tt->rn_flags |= x->rn_flags & RNF_NORMAL;
596 b_leaf = -1 - t->rn_b;
597 if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r;
598 /* Promote general routes from below */
600 for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
601 if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) {
602 if ((*mp = m = rn_new_radix_mask(x, 0)))
605 } else if (x->rn_mklist) {
607 * Skip over masks whose index is > that of new node
609 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
610 if (m->rm_b >= b_leaf)
612 t->rn_mklist = m; *mp = NULL;
615 /* Add new route to highest possible ancestor's list */
616 if ((netmask == 0) || (b > t->rn_b ))
617 return tt; /* can't lift at all */
622 } while (b <= t->rn_b && x != top);
624 * Search through routes associated with node to
625 * insert new route according to index.
626 * Need same criteria as when sorting dupedkeys to avoid
627 * double loop on deletion.
629 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
630 if (m->rm_b < b_leaf)
632 if (m->rm_b > b_leaf)
634 if (m->rm_flags & RNF_NORMAL) {
635 mmask = m->rm_leaf->rn_mask;
636 if (tt->rn_flags & RNF_NORMAL) {
638 "Non-unique normal route, mask not entered");
643 if (mmask == netmask) {
648 if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
651 *mp = rn_new_radix_mask(tt, *mp);
656 rn_delete(void *v_arg,
658 struct radix_node_head *head)
660 struct radix_node *t, *p, *x, *tt;
661 struct radix_mask *m, *saved_m, **mp;
662 struct radix_node *dupedkey, *saved_tt, *top;
664 int b, head_off, vlen;
667 netmask = netmask_arg;
668 x = head->rnh_treetop;
669 tt = rn_search(v, x);
670 head_off = x->rn_off;
675 Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
678 * Delete our route from mask lists.
681 if ((x = rn_addmask(netmask, 1, head_off)) == NULL)
684 while (tt->rn_mask != netmask)
685 if ((tt = tt->rn_dupedkey) == NULL)
688 if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == NULL)
690 if (tt->rn_flags & RNF_NORMAL) {
691 if (m->rm_leaf != tt || m->rm_refs > 0) {
692 log(LOG_ERR, "rn_delete: inconsistent annotation\n");
693 return 0; /* dangling ref could cause disaster */
696 if (m->rm_mask != tt->rn_mask) {
697 log(LOG_ERR, "rn_delete: inconsistent annotation\n");
700 if (--m->rm_refs >= 0)
706 goto on1; /* Wasn't lifted at all */
710 } while (b <= t->rn_b && x != top);
711 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
718 log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
719 if (tt->rn_flags & RNF_NORMAL)
720 return (0); /* Dangling ref to us */
724 * Eliminate us from tree
726 if (tt->rn_flags & RNF_ROOT)
729 /* Get us out of the creation list */
730 for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
731 if (t) t->rn_ybro = tt->rn_ybro;
734 if ((dupedkey = saved_tt->rn_dupedkey)) {
735 if (tt == saved_tt) {
736 x = dupedkey; x->rn_p = t;
737 if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x;
739 for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
741 if (p) p->rn_dupedkey = tt->rn_dupedkey;
742 else log(LOG_ERR, "rn_delete: couldn't find us\n");
745 if (t->rn_flags & RNF_ACTIVE) {
747 *++x = *t; p = t->rn_p;
749 b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p;
751 if (p->rn_l == t) p->rn_l = x; else p->rn_r = x;
752 x->rn_l->rn_p = x; x->rn_r->rn_p = x;
756 if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l;
758 if (p->rn_r == t) p->rn_r = x; else p->rn_l = x;
761 * Demote routes attached to us.
765 for (mp = &x->rn_mklist; (m = *mp);)
769 /* If there are any key,mask pairs in a sibling
770 duped-key chain, some subset will appear sorted
771 in the same order attached to our mklist */
772 for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
773 if (m == x->rn_mklist) {
774 struct radix_mask *mm = m->rm_mklist;
776 if (--(m->rm_refs) < 0)
781 syslog(LOG_ERR, "%s 0x%lx at 0x%lx\n",
782 "rn_delete: Orphaned Mask",
788 * We may be holding an active internal node in the tree.
795 b = t->rn_info; *t = *x; t->rn_info = b;
797 t->rn_l->rn_p = t; t->rn_r->rn_p = t;
799 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t;
802 tt->rn_flags &= ~RNF_ACTIVE;
803 tt[1].rn_flags &= ~RNF_ACTIVE;
808 rn_walktree(struct radix_node_head *h,
809 int (*f)(struct radix_node *, struct walkarg *),
813 struct radix_node *base, *next;
814 struct radix_node *rn = h->rnh_treetop;
816 * This gets complicated because we may delete the node
817 * while applying the function f to it, so we need to calculate
818 * the successor node in advance.
820 /* First time through node, go left */
821 while (rn->rn_b >= 0)
825 /* If at right child go back up, otherwise, go right */
826 while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0)
828 /* Find the next *leaf* since next node might vanish, too */
829 for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;)
833 while ((rn = base)) {
834 base = rn->rn_dupedkey;
835 if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w)))
839 if (rn->rn_flags & RNF_ROOT)
846 rn_inithead(struct radix_node_head **head, int off)
848 struct radix_node_head *rnh;
849 struct radix_node *t, *tt, *ttt;
852 rnh = (struct radix_node_head *)rtmalloc(sizeof(*rnh), "rn_inithead");
853 Bzero(rnh, sizeof (*rnh));
855 t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
856 ttt = rnh->rnh_nodes + 2;
860 tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
863 ttt->rn_key = rn_ones;
864 rnh->rnh_addaddr = rn_addroute;
865 rnh->rnh_deladdr = rn_delete;
866 rnh->rnh_matchaddr = rn_match;
867 rnh->rnh_lookup = rn_lookup;
868 rnh->rnh_walktree = rn_walktree;
869 rnh->rnh_treetop = t;
877 if (max_keylen == 0) {
878 printf("rn_init: radix functions require max_keylen be set\n");
881 rn_zeros = (char *)rtmalloc(3 * max_keylen, "rn_init");
882 Bzero(rn_zeros, 3 * max_keylen);
883 rn_ones = cp = rn_zeros + max_keylen;
884 addmask_key = cplim = rn_ones + max_keylen;
887 if (rn_inithead(&mask_rnhead, 0) == 0)