2 * Copyright (c) 1988, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
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20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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29 * @(#)radix.c 8.4 (Berkeley) 11/2/94
35 * Routines to build and maintain radix trees for routing lookups.
42 #elif defined(__FreeBSD__)
45 __RCSID("$Revision: 2.23 $");
46 #ident "$Revision: 2.23 $"
49 #define log(x, msg) syslog(x, msg)
50 #define panic(s) {log(LOG_ERR,s); exit(1);}
51 #define min(a,b) (((a)<(b))?(a):(b))
54 struct radix_mask *rn_mkfreelist;
55 struct radix_node_head *mask_rnhead;
56 static char *addmask_key;
57 static char normal_chars[] = {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
58 static char *rn_zeros, *rn_ones;
60 #define rn_masktop (mask_rnhead->rnh_treetop)
62 #define Bcmp(a, b, l) (l == 0 ? 0 \
63 : memcmp((caddr_t)(a), (caddr_t)(b), (size_t)l))
65 static int rn_satisfies_leaf(char *, struct radix_node *, int);
68 * The data structure for the keys is a radix tree with one way
69 * branching removed. The index rn_b at an internal node n represents a bit
70 * position to be tested. The tree is arranged so that all descendants
71 * of a node n have keys whose bits all agree up to position rn_b - 1.
72 * (We say the index of n is rn_b.)
74 * There is at least one descendant which has a one bit at position rn_b,
75 * and at least one with a zero there.
77 * A route is determined by a pair of key and mask. We require that the
78 * bit-wise logical and of the key and mask to be the key.
79 * We define the index of a route to associated with the mask to be
80 * the first bit number in the mask where 0 occurs (with bit number 0
81 * representing the highest order bit).
83 * We say a mask is normal if every bit is 0, past the index of the mask.
84 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
85 * and m is a normal mask, then the route applies to every descendant of n.
86 * If the index(m) < rn_b, this implies the trailing last few bits of k
87 * before bit b are all 0, (and hence consequently true of every descendant
88 * of n), so the route applies to all descendants of the node as well.
90 * Similar logic shows that a non-normal mask m such that
91 * index(m) <= index(n) could potentially apply to many children of n.
92 * Thus, for each non-host route, we attach its mask to a list at an internal
93 * node as high in the tree as we can go.
95 * The present version of the code makes use of normal routes in short-
96 * circuiting an explict mask and compare operation when testing whether
97 * a key satisfies a normal route, and also in remembering the unique leaf
98 * that governs a subtree.
102 rn_search(void *v_arg,
103 struct radix_node *head)
105 struct radix_node *x;
108 for (x = head, v = v_arg; x->rn_b >= 0;) {
109 if (x->rn_bmask & v[x->rn_off])
118 rn_search_m(void *v_arg,
119 struct radix_node *head,
122 struct radix_node *x;
123 caddr_t v = v_arg, m = m_arg;
125 for (x = head; x->rn_b >= 0;) {
126 if ((x->rn_bmask & m[x->rn_off]) &&
127 (x->rn_bmask & v[x->rn_off]))
136 rn_refines(void* m_arg, void *n_arg)
138 caddr_t m = m_arg, n = n_arg;
139 caddr_t lim, lim2 = lim = n + *(u_char *)n;
140 int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
141 int masks_are_equal = 1;
154 if (masks_are_equal && (longer < 0))
155 for (lim2 = m - longer; m < lim2; )
158 return (!masks_are_equal);
162 rn_lookup(void *v_arg, void *m_arg, struct radix_node_head *head)
164 struct radix_node *x;
168 if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == 0)
172 x = rn_match(v_arg, head);
174 while (x && x->rn_mask != netmask)
181 rn_satisfies_leaf(char *trial,
182 struct radix_node *leaf,
185 char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
187 int length = min(*(u_char *)cp, *(u_char *)cp2);
192 length = min(length, *(u_char *)cp3);
193 cplim = cp + length; cp3 += skip; cp2 += skip;
194 for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
195 if ((*cp ^ *cp2) & *cp3)
201 rn_match(void *v_arg,
202 struct radix_node_head *head)
205 struct radix_node *t = head->rnh_treetop, *x;
208 struct radix_node *saved_t, *top = t;
209 int off = t->rn_off, vlen = *(u_char *)cp, matched_off;
213 * Open code rn_search(v, top) to avoid overhead of extra
216 for (; t->rn_b >= 0; ) {
217 if (t->rn_bmask & cp[t->rn_off])
223 * See if we match exactly as a host destination
224 * or at least learn how many bits match, for normal mask finesse.
226 * It doesn't hurt us to limit how many bytes to check
227 * to the length of the mask, since if it matches we had a genuine
228 * match and the leaf we have is the most specific one anyway;
229 * if it didn't match with a shorter length it would fail
230 * with a long one. This wins big for class B&C netmasks which
231 * are probably the most common case...
234 vlen = *(u_char *)t->rn_mask;
235 cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
236 for (; cp < cplim; cp++, cp2++)
240 * This extra grot is in case we are explicitly asked
241 * to look up the default. Ugh!
244 * In this case, we have a complete match of the key. Unless
245 * the node is one of the roots, we are finished.
246 * If it is the zeros root, then take what we have, prefering
248 * If it is the ones root, then pretend the target key was followed
249 * by a byte of zeros.
251 if (!(t->rn_flags & RNF_ROOT))
252 return t; /* not a root */
253 if (t->rn_dupedkey) {
255 return t; /* have some real data */
258 return t; /* not the ones root */
259 b = 0; /* fake a zero after 255.255.255.255 */
262 test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
263 for (b = 7; (test >>= 1) > 0;)
266 matched_off = cp - v;
267 b += matched_off << 3;
270 * If there is a host route in a duped-key chain, it will be first.
272 if ((saved_t = t)->rn_mask == 0)
274 for (; t; t = t->rn_dupedkey) {
276 * Even if we don't match exactly as a host,
277 * we may match if the leaf we wound up at is
280 if (t->rn_flags & RNF_NORMAL) {
283 } else if (rn_satisfies_leaf(v, t, matched_off)) {
288 /* start searching up the tree */
290 struct radix_mask *m;
292 if ((m = t->rn_mklist)) {
294 * If non-contiguous masks ever become important
295 * we can restore the masking and open coding of
296 * the search and satisfaction test and put the
297 * calculation of "off" back before the "do".
300 if (m->rm_flags & RNF_NORMAL) {
304 off = min(t->rn_off, matched_off);
305 x = rn_search_m(v, t, m->rm_mask);
306 while (x && x->rn_mask != m->rm_mask)
308 if (x && rn_satisfies_leaf(v, x, off))
311 } while ((m = m->rm_mklist));
319 struct radix_node *rn_clist;
325 rn_newpair(void *v, int b, struct radix_node nodes[2])
327 struct radix_node *tt = nodes, *t = tt + 1;
328 t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7);
329 t->rn_l = tt; t->rn_off = b >> 3;
330 tt->rn_b = -1; tt->rn_key = (caddr_t)v; tt->rn_p = t;
331 tt->rn_flags = t->rn_flags = RNF_ACTIVE;
333 tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
334 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
340 rn_insert(void* v_arg,
341 struct radix_node_head *head,
343 struct radix_node nodes[2])
346 struct radix_node *top = head->rnh_treetop;
347 int head_off = top->rn_off, vlen = (int)*((u_char *)v);
348 struct radix_node *t = rn_search(v_arg, top);
349 caddr_t cp = v + head_off;
351 struct radix_node *tt;
354 * Find first bit at which v and t->rn_key differ
357 caddr_t cp2 = t->rn_key + head_off;
359 caddr_t cplim = v + vlen;
364 /* handle adding 255.255.255.255 */
365 if (!(t->rn_flags & RNF_ROOT) || *(cp2-1) == 0) {
371 cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
372 for (b = (cp - v) << 3; cmp_res; b--)
376 struct radix_node *p, *x = top;
380 if (cp[x->rn_off] & x->rn_bmask)
383 } while ((unsigned)b > (unsigned)x->rn_b);
386 log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p);
388 t = rn_newpair(v_arg, b, nodes); tt = t->rn_l;
389 if ((cp[p->rn_off] & p->rn_bmask) == 0)
393 x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */
394 if ((cp[t->rn_off] & t->rn_bmask) == 0) {
397 t->rn_r = tt; t->rn_l = x;
401 log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
408 rn_addmask(void *n_arg, int search, int skip)
410 caddr_t netmask = (caddr_t)n_arg;
411 struct radix_node *x;
414 int maskduplicated, m0, isnormal;
415 struct radix_node *saved_x;
416 static int last_zeroed = 0;
418 if ((mlen = *(u_char *)netmask) > max_keylen)
423 return (mask_rnhead->rnh_nodes);
425 Bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
426 if ((m0 = mlen) > skip)
427 Bcopy(netmask + skip, addmask_key + skip, mlen - skip);
429 * Trim trailing zeroes.
431 for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
433 mlen = cp - addmask_key;
435 if (m0 >= last_zeroed)
437 return (mask_rnhead->rnh_nodes);
439 if (m0 < last_zeroed)
440 Bzero(addmask_key + m0, last_zeroed - m0);
441 *addmask_key = last_zeroed = mlen;
442 x = rn_search(addmask_key, rn_masktop);
443 if (Bcmp(addmask_key, x->rn_key, mlen) != 0)
447 x = (struct radix_node *)rtmalloc(max_keylen + 2*sizeof(*x),
450 Bzero(x, max_keylen + 2 * sizeof (*x));
451 netmask = cp = (caddr_t)(x + 2);
452 Bcopy(addmask_key, cp, mlen);
453 x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
454 if (maskduplicated) {
455 log(LOG_ERR, "rn_addmask: mask impossibly already in tree");
460 * Calculate index of mask, and check for normalcy.
462 cplim = netmask + mlen; isnormal = 1;
463 for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
466 for (j = 0x80; (j & *cp) != 0; j >>= 1)
468 if (*cp != normal_chars[b] || cp != (cplim - 1))
471 b += (cp - netmask) << 3;
474 x->rn_flags |= RNF_NORMAL;
478 static int /* XXX: arbitrary ordering for non-contiguous masks */
479 rn_lexobetter(void *m_arg, void *n_arg)
481 u_char *mp = m_arg, *np = n_arg, *lim;
484 return 1; /* not really, but need to check longer one first */
486 for (lim = mp + *mp; mp < lim;)
492 static struct radix_mask *
493 rn_new_radix_mask(struct radix_node *tt,
494 struct radix_mask *next)
496 struct radix_mask *m;
500 log(LOG_ERR, "Mask for route not entered\n");
505 m->rm_flags = tt->rn_flags;
506 if (tt->rn_flags & RNF_NORMAL)
509 m->rm_mask = tt->rn_mask;
516 rn_addroute(void *v_arg,
518 struct radix_node_head *head,
519 struct radix_node treenodes[2])
521 caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
522 struct radix_node *t, *x = 0, *tt;
523 struct radix_node *saved_tt, *top = head->rnh_treetop;
524 short b = 0, b_leaf = 0;
527 struct radix_mask *m, **mp;
530 * In dealing with non-contiguous masks, there may be
531 * many different routes which have the same mask.
532 * We will find it useful to have a unique pointer to
533 * the mask to speed avoiding duplicate references at
534 * nodes and possibly save time in calculating indices.
537 if ((x = rn_addmask(netmask, 0, top->rn_off)) == 0)
544 * Deal with duplicated keys: attach node to previous instance
546 saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
548 for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
549 if (tt->rn_mask == netmask)
553 ((b_leaf < tt->rn_b) || /* index(netmask) > node */
554 rn_refines(netmask, tt->rn_mask) ||
555 rn_lexobetter(netmask, tt->rn_mask))))
559 * If the mask is not duplicated, we wouldn't
560 * find it among possible duplicate key entries
561 * anyway, so the above test doesn't hurt.
563 * We sort the masks for a duplicated key the same way as
564 * in a masklist -- most specific to least specific.
565 * This may require the unfortunate nuisance of relocating
566 * the head of the list.
568 if (tt == saved_tt) {
569 struct radix_node *xx = x;
570 /* link in at head of list */
571 (tt = treenodes)->rn_dupedkey = t;
572 tt->rn_flags = t->rn_flags;
573 tt->rn_p = x = t->rn_p;
574 if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt;
575 saved_tt = tt; x = xx;
577 (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
581 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
582 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
584 tt->rn_key = (caddr_t) v;
586 tt->rn_flags = RNF_ACTIVE;
592 tt->rn_mask = netmask;
594 tt->rn_flags |= x->rn_flags & RNF_NORMAL;
599 b_leaf = -1 - t->rn_b;
600 if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r;
601 /* Promote general routes from below */
603 for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
604 if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) {
605 if ((*mp = m = rn_new_radix_mask(x, 0)))
608 } else if (x->rn_mklist) {
610 * Skip over masks whose index is > that of new node
612 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
613 if (m->rm_b >= b_leaf)
615 t->rn_mklist = m; *mp = 0;
618 /* Add new route to highest possible ancestor's list */
619 if ((netmask == 0) || (b > t->rn_b ))
620 return tt; /* can't lift at all */
625 } while (b <= t->rn_b && x != top);
627 * Search through routes associated with node to
628 * insert new route according to index.
629 * Need same criteria as when sorting dupedkeys to avoid
630 * double loop on deletion.
632 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
633 if (m->rm_b < b_leaf)
635 if (m->rm_b > b_leaf)
637 if (m->rm_flags & RNF_NORMAL) {
638 mmask = m->rm_leaf->rn_mask;
639 if (tt->rn_flags & RNF_NORMAL) {
641 "Non-unique normal route, mask not entered");
646 if (mmask == netmask) {
651 if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
654 *mp = rn_new_radix_mask(tt, *mp);
659 rn_delete(void *v_arg,
661 struct radix_node_head *head)
663 struct radix_node *t, *p, *x, *tt;
664 struct radix_mask *m, *saved_m, **mp;
665 struct radix_node *dupedkey, *saved_tt, *top;
667 int b, head_off, vlen;
670 netmask = netmask_arg;
671 x = head->rnh_treetop;
672 tt = rn_search(v, x);
673 head_off = x->rn_off;
678 Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
681 * Delete our route from mask lists.
684 if ((x = rn_addmask(netmask, 1, head_off)) == 0)
687 while (tt->rn_mask != netmask)
688 if ((tt = tt->rn_dupedkey) == 0)
691 if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
693 if (tt->rn_flags & RNF_NORMAL) {
694 if (m->rm_leaf != tt || m->rm_refs > 0) {
695 log(LOG_ERR, "rn_delete: inconsistent annotation\n");
696 return 0; /* dangling ref could cause disaster */
699 if (m->rm_mask != tt->rn_mask) {
700 log(LOG_ERR, "rn_delete: inconsistent annotation\n");
703 if (--m->rm_refs >= 0)
709 goto on1; /* Wasn't lifted at all */
713 } while (b <= t->rn_b && x != top);
714 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
721 log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
722 if (tt->rn_flags & RNF_NORMAL)
723 return (0); /* Dangling ref to us */
727 * Eliminate us from tree
729 if (tt->rn_flags & RNF_ROOT)
732 /* Get us out of the creation list */
733 for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
734 if (t) t->rn_ybro = tt->rn_ybro;
737 if ((dupedkey = saved_tt->rn_dupedkey)) {
738 if (tt == saved_tt) {
739 x = dupedkey; x->rn_p = t;
740 if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x;
742 for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
744 if (p) p->rn_dupedkey = tt->rn_dupedkey;
745 else log(LOG_ERR, "rn_delete: couldn't find us\n");
748 if (t->rn_flags & RNF_ACTIVE) {
750 *++x = *t; p = t->rn_p;
752 b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p;
754 if (p->rn_l == t) p->rn_l = x; else p->rn_r = x;
755 x->rn_l->rn_p = x; x->rn_r->rn_p = x;
759 if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l;
761 if (p->rn_r == t) p->rn_r = x; else p->rn_l = x;
764 * Demote routes attached to us.
768 for (mp = &x->rn_mklist; (m = *mp);)
772 /* If there are any key,mask pairs in a sibling
773 duped-key chain, some subset will appear sorted
774 in the same order attached to our mklist */
775 for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
776 if (m == x->rn_mklist) {
777 struct radix_mask *mm = m->rm_mklist;
779 if (--(m->rm_refs) < 0)
784 syslog(LOG_ERR, "%s 0x%lx at 0x%lx\n",
785 "rn_delete: Orphaned Mask",
791 * We may be holding an active internal node in the tree.
798 b = t->rn_info; *t = *x; t->rn_info = b;
800 t->rn_l->rn_p = t; t->rn_r->rn_p = t;
802 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t;
805 tt->rn_flags &= ~RNF_ACTIVE;
806 tt[1].rn_flags &= ~RNF_ACTIVE;
811 rn_walktree(struct radix_node_head *h,
812 int (*f)(struct radix_node *, struct walkarg *),
816 struct radix_node *base, *next;
817 struct radix_node *rn = h->rnh_treetop;
819 * This gets complicated because we may delete the node
820 * while applying the function f to it, so we need to calculate
821 * the successor node in advance.
823 /* First time through node, go left */
824 while (rn->rn_b >= 0)
828 /* If at right child go back up, otherwise, go right */
829 while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0)
831 /* Find the next *leaf* since next node might vanish, too */
832 for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;)
836 while ((rn = base)) {
837 base = rn->rn_dupedkey;
838 if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w)))
842 if (rn->rn_flags & RNF_ROOT)
849 rn_inithead(void **head, int off)
851 struct radix_node_head *rnh;
852 struct radix_node *t, *tt, *ttt;
855 rnh = (struct radix_node_head *)rtmalloc(sizeof(*rnh), "rn_inithead");
856 Bzero(rnh, sizeof (*rnh));
858 t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
859 ttt = rnh->rnh_nodes + 2;
863 tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
866 ttt->rn_key = rn_ones;
867 rnh->rnh_addaddr = rn_addroute;
868 rnh->rnh_deladdr = rn_delete;
869 rnh->rnh_matchaddr = rn_match;
870 rnh->rnh_lookup = rn_lookup;
871 rnh->rnh_walktree = rn_walktree;
872 rnh->rnh_treetop = t;
880 if (max_keylen == 0) {
881 printf("rn_init: radix functions require max_keylen be set\n");
884 rn_zeros = (char *)rtmalloc(3 * max_keylen, "rn_init");
885 Bzero(rn_zeros, 3 * max_keylen);
886 rn_ones = cp = rn_zeros + max_keylen;
887 addmask_key = cplim = rn_ones + max_keylen;
890 if (rn_inithead((void **)&mask_rnhead, 0) == 0)