sbin/routed/radix.c

   1 /*      $NetBSD: radix.c,v 1.12 2002/12/06 02:18:37 thorpej Exp $       */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgment:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  *      @(#)radix.c     8.4 (Berkeley) 11/2/94
  36  */
  37
  38 /*
  39  * Routines to build and maintain radix trees for routing lookups.
  40  */
  41
  42 #include "defs.h"
  43
  44 #ifdef __NetBSD__
  45 __RCSID("$NetBSD: radix.c,v 1.12 2002/12/06 02:18:37 thorpej Exp $");
  46 #elif defined(__FreeBSD__)
  47 __RCSID("$FreeBSD$");
  48 #else
  49 __RCSID("Revision: 2.23 ");
  50 #ident "Revision: 2.23 "
  51 #endif
  52
  53 #define log(x, msg) syslog(x, msg)
  54 #define panic(s) {log(LOG_ERR,s); exit(1);}
  55 #define min(a,b) (((a)<(b))?(a):(b))
  56
  57 int     max_keylen;
  58 struct radix_mask *rn_mkfreelist;
  59 struct radix_node_head *mask_rnhead;
  60 static char *addmask_key;
  61 static char normal_chars[] = {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
  62 static char *rn_zeros, *rn_ones;
  63
  64 #define rn_masktop (mask_rnhead->rnh_treetop)
  65 #undef Bcmp
  66 #define Bcmp(a, b, l) (l == 0 ? 0 \
  67                        : memcmp((caddr_t)(a), (caddr_t)(b), (size_t)l))
  68
  69 static int rn_satisfies_leaf(char *, struct radix_node *, int);
  70
  71 /*
  72  * The data structure for the keys is a radix tree with one way
  73  * branching removed.  The index rn_b at an internal node n represents a bit
  74  * position to be tested.  The tree is arranged so that all descendants
  75  * of a node n have keys whose bits all agree up to position rn_b - 1.
  76  * (We say the index of n is rn_b.)
  77  *
  78  * There is at least one descendant which has a one bit at position rn_b,
  79  * and at least one with a zero there.
  80  *
  81  * A route is determined by a pair of key and mask.  We require that the
  82  * bit-wise logical and of the key and mask to be the key.
  83  * We define the index of a route to associated with the mask to be
  84  * the first bit number in the mask where 0 occurs (with bit number 0
  85  * representing the highest order bit).
  86  *
  87  * We say a mask is normal if every bit is 0, past the index of the mask.
  88  * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
  89  * and m is a normal mask, then the route applies to every descendant of n.
  90  * If the index(m) < rn_b, this implies the trailing last few bits of k
  91  * before bit b are all 0, (and hence consequently true of every descendant
  92  * of n), so the route applies to all descendants of the node as well.
  93  *
  94  * Similar logic shows that a non-normal mask m such that
  95  * index(m) <= index(n) could potentially apply to many children of n.
  96  * Thus, for each non-host route, we attach its mask to a list at an internal
  97  * node as high in the tree as we can go.
  98  *
  99  * The present version of the code makes use of normal routes in short-
 100  * circuiting an explicit mask and compare operation when testing whether
 101  * a key satisfies a normal route, and also in remembering the unique leaf
 102  * that governs a subtree.
 103  */
 104
 105 struct radix_node *
 106 rn_search(void *v_arg,
 107           struct radix_node *head)
 108 {
 109         struct radix_node *x;
 110         caddr_t v;
 111
 112         for (x = head, v = v_arg; x->rn_b >= 0;) {
 113                 if (x->rn_bmask & v[x->rn_off])
 114                         x = x->rn_r;
 115                 else
 116                         x = x->rn_l;
 117         }
 118         return (x);
 119 }
 120
 121 struct radix_node *
 122 rn_search_m(void *v_arg,
 123             struct radix_node *head,
 124             void *m_arg)
 125 {
 126         struct radix_node *x;
 127         caddr_t v = v_arg, m = m_arg;
 128
 129         for (x = head; x->rn_b >= 0;) {
 130                 if ((x->rn_bmask & m[x->rn_off]) &&
 131                     (x->rn_bmask & v[x->rn_off]))
 132                         x = x->rn_r;
 133                 else
 134                         x = x->rn_l;
 135         }
 136         return x;
 137 }
 138
 139 int
 140 rn_refines(void* m_arg, void *n_arg)
 141 {
 142         caddr_t m = m_arg, n = n_arg;
 143         caddr_t lim, lim2 = lim = n + *(u_char *)n;
 144         int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
 145         int masks_are_equal = 1;
 146
 147         if (longer > 0)
 148                 lim -= longer;
 149         while (n < lim) {
 150                 if (*n & ~(*m))
 151                         return 0;
 152                 if (*n++ != *m++)
 153                         masks_are_equal = 0;
 154         }
 155         while (n < lim2)
 156                 if (*n++)
 157                         return 0;
 158         if (masks_are_equal && (longer < 0))
 159                 for (lim2 = m - longer; m < lim2; )
 160                         if (*m++)
 161                                 return 1;
 162         return (!masks_are_equal);
 163 }
 164
 165 struct radix_node *
 166 rn_lookup(void *v_arg, void *m_arg, struct radix_node_head *head)
 167 {
 168         struct radix_node *x;
 169         caddr_t netmask = 0;
 170
 171         if (m_arg) {
 172                 if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == 0)
 173                         return (0);
 174                 netmask = x->rn_key;
 175         }
 176         x = rn_match(v_arg, head);
 177         if (x && netmask) {
 178                 while (x && x->rn_mask != netmask)
 179                         x = x->rn_dupedkey;
 180         }
 181         return x;
 182 }
 183
 184 static int
 185 rn_satisfies_leaf(char *trial,
 186                   struct radix_node *leaf,
 187                   int skip)
 188 {
 189         char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
 190         char *cplim;
 191         int length = min(*(u_char *)cp, *(u_char *)cp2);
 192
 193         if (cp3 == 0)
 194                 cp3 = rn_ones;
 195         else
 196                 length = min(length, *(u_char *)cp3);
 197         cplim = cp + length; cp3 += skip; cp2 += skip;
 198         for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
 199                 if ((*cp ^ *cp2) & *cp3)
 200                         return 0;
 201         return 1;
 202 }
 203
 204 struct radix_node *
 205 rn_match(void *v_arg,
 206          struct radix_node_head *head)
 207 {
 208         caddr_t v = v_arg;
 209         struct radix_node *t = head->rnh_treetop, *x;
 210         caddr_t cp = v, cp2;
 211         caddr_t cplim;
 212         struct radix_node *saved_t, *top = t;
 213         int off = t->rn_off, vlen = *(u_char *)cp, matched_off;
 214         int test, b, rn_b;
 215
 216         /*
 217          * Open code rn_search(v, top) to avoid overhead of extra
 218          * subroutine call.
 219          */
 220         for (; t->rn_b >= 0; ) {
 221                 if (t->rn_bmask & cp[t->rn_off])
 222                         t = t->rn_r;
 223                 else
 224                         t = t->rn_l;
 225         }
 226         /*
 227          * See if we match exactly as a host destination
 228          * or at least learn how many bits match, for normal mask finesse.
 229          *
 230          * It doesn't hurt us to limit how many bytes to check
 231          * to the length of the mask, since if it matches we had a genuine
 232          * match and the leaf we have is the most specific one anyway;
 233          * if it didn't match with a shorter length it would fail
 234          * with a long one.  This wins big for class B&C netmasks which
 235          * are probably the most common case...
 236          */
 237         if (t->rn_mask)
 238                 vlen = *(u_char *)t->rn_mask;
 239         cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
 240         for (; cp < cplim; cp++, cp2++)
 241                 if (*cp != *cp2)
 242                         goto on1;
 243         /*
 244          * This extra grot is in case we are explicitly asked
 245          * to look up the default.  Ugh!
 246          * Or 255.255.255.255
 247          *
 248          * In this case, we have a complete match of the key.  Unless
 249          * the node is one of the roots, we are finished.
 250          * If it is the zeros root, then take what we have, prefering
 251          * any real data.
 252          * If it is the ones root, then pretend the target key was followed
 253          * by a byte of zeros.
 254          */
 255         if (!(t->rn_flags & RNF_ROOT))
 256                 return t;               /* not a root */
 257         if (t->rn_dupedkey) {
 258                 t = t->rn_dupedkey;
 259                 return t;               /* have some real data */
 260         }
 261         if (*(cp-1) == 0)
 262                 return t;               /* not the ones root */
 263         b = 0;                          /* fake a zero after 255.255.255.255 */
 264         goto on2;
 265 on1:
 266         test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
 267         for (b = 7; (test >>= 1) > 0;)
 268                 b--;
 269 on2:
 270         matched_off = cp - v;
 271         b += matched_off << 3;
 272         rn_b = -1 - b;
 273         /*
 274          * If there is a host route in a duped-key chain, it will be first.
 275          */
 276         if ((saved_t = t)->rn_mask == 0)
 277                 t = t->rn_dupedkey;
 278         for (; t; t = t->rn_dupedkey) {
 279                 /*
 280                  * Even if we don't match exactly as a host,
 281                  * we may match if the leaf we wound up at is
 282                  * a route to a net.
 283                  */
 284                 if (t->rn_flags & RNF_NORMAL) {
 285                         if (rn_b <= t->rn_b)
 286                                 return t;
 287                 } else if (rn_satisfies_leaf(v, t, matched_off)) {
 288                         return t;
 289                 }
 290         }
 291         t = saved_t;
 292         /* start searching up the tree */
 293         do {
 294                 struct radix_mask *m;
 295                 t = t->rn_p;
 296                 if ((m = t->rn_mklist)) {
 297                         /*
 298                          * If non-contiguous masks ever become important
 299                          * we can restore the masking and open coding of
 300                          * the search and satisfaction test and put the
 301                          * calculation of "off" back before the "do".
 302                          */
 303                         do {
 304                                 if (m->rm_flags & RNF_NORMAL) {
 305                                         if (rn_b <= m->rm_b)
 306                                                 return (m->rm_leaf);
 307                                 } else {
 308                                         off = min(t->rn_off, matched_off);
 309                                         x = rn_search_m(v, t, m->rm_mask);
 310                                         while (x && x->rn_mask != m->rm_mask)
 311                                                 x = x->rn_dupedkey;
 312                                         if (x && rn_satisfies_leaf(v, x, off))
 313                                                     return x;
 314                                 }
 315                         } while ((m = m->rm_mklist));
 316                 }
 317         } while (t != top);
 318         return 0;
 319 }
 320
 321 #ifdef RN_DEBUG
 322 int     rn_nodenum;
 323 struct  radix_node *rn_clist;
 324 int     rn_saveinfo;
 325 int     rn_debug =  1;
 326 #endif
 327
 328 struct radix_node *
 329 rn_newpair(void *v, int b, struct radix_node nodes[2])
 330 {
 331         struct radix_node *tt = nodes, *t = tt + 1;
 332         t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7);
 333         t->rn_l = tt; t->rn_off = b >> 3;
 334         tt->rn_b = -1; tt->rn_key = (caddr_t)v; tt->rn_p = t;
 335         tt->rn_flags = t->rn_flags = RNF_ACTIVE;
 336 #ifdef RN_DEBUG
 337         tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
 338         tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
 339 #endif
 340         return t;
 341 }
 342
 343 struct radix_node *
 344 rn_insert(void* v_arg,
 345           struct radix_node_head *head,
 346           int *dupentry,
 347           struct radix_node nodes[2])
 348 {
 349         caddr_t v = v_arg;
 350         struct radix_node *top = head->rnh_treetop;
 351         int head_off = top->rn_off, vlen = (int)*((u_char *)v);
 352         struct radix_node *t = rn_search(v_arg, top);
 353         caddr_t cp = v + head_off;
 354         int b;
 355         struct radix_node *tt;
 356
 357         /*
 358          * Find first bit at which v and t->rn_key differ
 359          */
 360     {
 361                 caddr_t cp2 = t->rn_key + head_off;
 362                 int cmp_res;
 363         caddr_t cplim = v + vlen;
 364
 365         while (cp < cplim)
 366                 if (*cp2++ != *cp++)
 367                         goto on1;
 368         /* handle adding 255.255.255.255 */
 369         if (!(t->rn_flags & RNF_ROOT) || *(cp2-1) == 0) {
 370                 *dupentry = 1;
 371                 return t;
 372         }
 373 on1:
 374         *dupentry = 0;
 375         cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
 376         for (b = (cp - v) << 3; cmp_res; b--)
 377                 cmp_res >>= 1;
 378     }
 379     {
 380             struct radix_node *p, *x = top;
 381         cp = v;
 382         do {
 383                 p = x;
 384                 if (cp[x->rn_off] & x->rn_bmask)
 385                         x = x->rn_r;
 386                 else x = x->rn_l;
 387         } while ((unsigned)b > (unsigned)x->rn_b);
 388 #ifdef RN_DEBUG
 389         if (rn_debug)
 390                 log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p);
 391 #endif
 392         t = rn_newpair(v_arg, b, nodes); tt = t->rn_l;
 393         if ((cp[p->rn_off] & p->rn_bmask) == 0)
 394                 p->rn_l = t;
 395         else
 396                 p->rn_r = t;
 397         x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */
 398         if ((cp[t->rn_off] & t->rn_bmask) == 0) {
 399                 t->rn_r = x;
 400         } else {
 401                 t->rn_r = tt; t->rn_l = x;
 402         }
 403 #ifdef RN_DEBUG
 404         if (rn_debug)
 405                 log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
 406 #endif
 407     }
 408         return (tt);
 409 }
 410
 411 struct radix_node *
 412 rn_addmask(void *n_arg, int search, int skip)
 413 {
 414         caddr_t netmask = (caddr_t)n_arg;
 415         struct radix_node *x;
 416         caddr_t cp, cplim;
 417         int b = 0, mlen, j;
 418         int maskduplicated, m0, isnormal;
 419         struct radix_node *saved_x;
 420         static int last_zeroed = 0;
 421
 422         if ((mlen = *(u_char *)netmask) > max_keylen)
 423                 mlen = max_keylen;
 424         if (skip == 0)
 425                 skip = 1;
 426         if (mlen <= skip)
 427                 return (mask_rnhead->rnh_nodes);
 428         if (skip > 1)
 429                 Bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
 430         if ((m0 = mlen) > skip)
 431                 Bcopy(netmask + skip, addmask_key + skip, mlen - skip);
 432         /*
 433          * Trim trailing zeroes.
 434          */
 435         for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
 436                 cp--;
 437         mlen = cp - addmask_key;
 438         if (mlen <= skip) {
 439                 if (m0 >= last_zeroed)
 440                         last_zeroed = mlen;
 441                 return (mask_rnhead->rnh_nodes);
 442         }
 443         if (m0 < last_zeroed)
 444                 Bzero(addmask_key + m0, last_zeroed - m0);
 445         *addmask_key = last_zeroed = mlen;
 446         x = rn_search(addmask_key, rn_masktop);
 447         if (Bcmp(addmask_key, x->rn_key, mlen) != 0)
 448                 x = 0;
 449         if (x || search)
 450                 return (x);
 451         x = (struct radix_node *)rtmalloc(max_keylen + 2*sizeof(*x),
 452                                           "rn_addmask");
 453         saved_x = x;
 454         Bzero(x, max_keylen + 2 * sizeof (*x));
 455         netmask = cp = (caddr_t)(x + 2);
 456         Bcopy(addmask_key, cp, mlen);
 457         x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
 458         if (maskduplicated) {
 459                 log(LOG_ERR, "rn_addmask: mask impossibly already in tree");
 460                 Free(saved_x);
 461                 return (x);
 462         }
 463         /*
 464          * Calculate index of mask, and check for normalcy.
 465          */
 466         cplim = netmask + mlen; isnormal = 1;
 467         for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
 468                 cp++;
 469         if (cp != cplim) {
 470                 for (j = 0x80; (j & *cp) != 0; j >>= 1)
 471                         b++;
 472                 if (*cp != normal_chars[b] || cp != (cplim - 1))
 473                         isnormal = 0;
 474         }
 475         b += (cp - netmask) << 3;
 476         x->rn_b = -1 - b;
 477         if (isnormal)
 478                 x->rn_flags |= RNF_NORMAL;
 479         return (x);
 480 }
 481
 482 static int      /* XXX: arbitrary ordering for non-contiguous masks */
 483 rn_lexobetter(void *m_arg, void *n_arg)
 484 {
 485         u_char *mp = m_arg, *np = n_arg, *lim;
 486
 487         if (*mp > *np)
 488                 return 1;  /* not really, but need to check longer one first */
 489         if (*mp == *np)
 490                 for (lim = mp + *mp; mp < lim;)
 491                         if (*mp++ > *np++)
 492                                 return 1;
 493         return 0;
 494 }
 495
 496 static struct radix_mask *
 497 rn_new_radix_mask(struct radix_node *tt,
 498                   struct radix_mask *next)
 499 {
 500         struct radix_mask *m;
 501
 502         MKGet(m);
 503         if (m == 0) {
 504                 log(LOG_ERR, "Mask for route not entered\n");
 505                 return (0);
 506         }
 507         Bzero(m, sizeof *m);
 508         m->rm_b = tt->rn_b;
 509         m->rm_flags = tt->rn_flags;
 510         if (tt->rn_flags & RNF_NORMAL)
 511                 m->rm_leaf = tt;
 512         else
 513                 m->rm_mask = tt->rn_mask;
 514         m->rm_mklist = next;
 515         tt->rn_mklist = m;
 516         return m;
 517 }
 518
 519 struct radix_node *
 520 rn_addroute(void *v_arg,
 521             void *n_arg,
 522             struct radix_node_head *head,
 523             struct radix_node treenodes[2])
 524 {
 525         caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
 526         struct radix_node *t, *x = 0, *tt;
 527         struct radix_node *saved_tt, *top = head->rnh_treetop;
 528         short b = 0, b_leaf = 0;
 529         int keyduplicated;
 530         caddr_t mmask;
 531         struct radix_mask *m, **mp;
 532
 533         /*
 534          * In dealing with non-contiguous masks, there may be
 535          * many different routes which have the same mask.
 536          * We will find it useful to have a unique pointer to
 537          * the mask to speed avoiding duplicate references at
 538          * nodes and possibly save time in calculating indices.
 539          */
 540         if (netmask)  {
 541                 if ((x = rn_addmask(netmask, 0, top->rn_off)) == 0)
 542                         return (0);
 543                 b_leaf = x->rn_b;
 544                 b = -1 - x->rn_b;
 545                 netmask = x->rn_key;
 546         }
 547         /*
 548          * Deal with duplicated keys: attach node to previous instance
 549          */
 550         saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
 551         if (keyduplicated) {
 552                 for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
 553                         if (tt->rn_mask == netmask)
 554                                 return (0);
 555                         if (netmask == 0 ||
 556                             (tt->rn_mask &&
 557                              ((b_leaf < tt->rn_b) || /* index(netmask) > node */
 558                                rn_refines(netmask, tt->rn_mask) ||
 559                                rn_lexobetter(netmask, tt->rn_mask))))
 560                                 break;
 561                 }
 562                 /*
 563                  * If the mask is not duplicated, we wouldn't
 564                  * find it among possible duplicate key entries
 565                  * anyway, so the above test doesn't hurt.
 566                  *
 567                  * We sort the masks for a duplicated key the same way as
 568                  * in a masklist -- most specific to least specific.
 569                  * This may require the unfortunate nuisance of relocating
 570                  * the head of the list.
 571                  */
 572                 if (tt == saved_tt) {
 573                         struct  radix_node *xx = x;
 574                         /* link in at head of list */
 575                         (tt = treenodes)->rn_dupedkey = t;
 576                         tt->rn_flags = t->rn_flags;
 577                         tt->rn_p = x = t->rn_p;
 578                         if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt;
 579                         saved_tt = tt; x = xx;
 580                 } else {
 581                         (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
 582                         t->rn_dupedkey = tt;
 583                 }
 584 #ifdef RN_DEBUG
 585                 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
 586                 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
 587 #endif
 588                 tt->rn_key = (caddr_t) v;
 589                 tt->rn_b = -1;
 590                 tt->rn_flags = RNF_ACTIVE;
 591         }
 592         /*
 593          * Put mask in tree.
 594          */
 595         if (netmask) {
 596                 tt->rn_mask = netmask;
 597                 tt->rn_b = x->rn_b;
 598                 tt->rn_flags |= x->rn_flags & RNF_NORMAL;
 599         }
 600         t = saved_tt->rn_p;
 601         if (keyduplicated)
 602                 goto on2;
 603         b_leaf = -1 - t->rn_b;
 604         if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r;
 605         /* Promote general routes from below */
 606         if (x->rn_b < 0) {
 607             for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
 608                 if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) {
 609                         if ((*mp = m = rn_new_radix_mask(x, 0)))
 610                                 mp = &m->rm_mklist;
 611                 }
 612         } else if (x->rn_mklist) {
 613                 /*
 614                  * Skip over masks whose index is > that of new node
 615                  */
 616                 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
 617                         if (m->rm_b >= b_leaf)
 618                                 break;
 619                 t->rn_mklist = m; *mp = 0;
 620         }
 621 on2:
 622         /* Add new route to highest possible ancestor's list */
 623         if ((netmask == 0) || (b > t->rn_b ))
 624                 return tt; /* can't lift at all */
 625         b_leaf = tt->rn_b;
 626         do {
 627                 x = t;
 628                 t = t->rn_p;
 629         } while (b <= t->rn_b && x != top);
 630         /*
 631          * Search through routes associated with node to
 632          * insert new route according to index.
 633          * Need same criteria as when sorting dupedkeys to avoid
 634          * double loop on deletion.
 635          */
 636         for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
 637                 if (m->rm_b < b_leaf)
 638                         continue;
 639                 if (m->rm_b > b_leaf)
 640                         break;
 641                 if (m->rm_flags & RNF_NORMAL) {
 642                         mmask = m->rm_leaf->rn_mask;
 643                         if (tt->rn_flags & RNF_NORMAL) {
 644                                 log(LOG_ERR,
 645                                    "Non-unique normal route, mask not entered");
 646                                 return tt;
 647                         }
 648                 } else
 649                         mmask = m->rm_mask;
 650                 if (mmask == netmask) {
 651                         m->rm_refs++;
 652                         tt->rn_mklist = m;
 653                         return tt;
 654                 }
 655                 if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
 656                         break;
 657         }
 658         *mp = rn_new_radix_mask(tt, *mp);
 659         return tt;
 660 }
 661
 662 struct radix_node *
 663 rn_delete(void *v_arg,
 664           void *netmask_arg,
 665           struct radix_node_head *head)
 666 {
 667         struct radix_node *t, *p, *x, *tt;
 668         struct radix_mask *m, *saved_m, **mp;
 669         struct radix_node *dupedkey, *saved_tt, *top;
 670         caddr_t v, netmask;
 671         int b, head_off, vlen;
 672
 673         v = v_arg;
 674         netmask = netmask_arg;
 675         x = head->rnh_treetop;
 676         tt = rn_search(v, x);
 677         head_off = x->rn_off;
 678         vlen =  *(u_char *)v;
 679         saved_tt = tt;
 680         top = x;
 681         if (tt == 0 ||
 682             Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
 683                 return (0);
 684         /*
 685          * Delete our route from mask lists.
 686          */
 687         if (netmask) {
 688                 if ((x = rn_addmask(netmask, 1, head_off)) == 0)
 689                         return (0);
 690                 netmask = x->rn_key;
 691                 while (tt->rn_mask != netmask)
 692                         if ((tt = tt->rn_dupedkey) == 0)
 693                                 return (0);
 694         }
 695         if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
 696                 goto on1;
 697         if (tt->rn_flags & RNF_NORMAL) {
 698                 if (m->rm_leaf != tt || m->rm_refs > 0) {
 699                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
 700                         return 0;  /* dangling ref could cause disaster */
 701                 }
 702         } else {
 703                 if (m->rm_mask != tt->rn_mask) {
 704                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
 705                         goto on1;
 706                 }
 707                 if (--m->rm_refs >= 0)
 708                         goto on1;
 709         }
 710         b = -1 - tt->rn_b;
 711         t = saved_tt->rn_p;
 712         if (b > t->rn_b)
 713                 goto on1; /* Wasn't lifted at all */
 714         do {
 715                 x = t;
 716                 t = t->rn_p;
 717         } while (b <= t->rn_b && x != top);
 718         for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
 719                 if (m == saved_m) {
 720                         *mp = m->rm_mklist;
 721                         MKFree(m);
 722                         break;
 723                 }
 724         if (m == 0) {
 725                 log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
 726                 if (tt->rn_flags & RNF_NORMAL)
 727                         return (0); /* Dangling ref to us */
 728         }
 729 on1:
 730         /*
 731          * Eliminate us from tree
 732          */
 733         if (tt->rn_flags & RNF_ROOT)
 734                 return (0);
 735 #ifdef RN_DEBUG
 736         /* Get us out of the creation list */
 737         for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
 738         if (t) t->rn_ybro = tt->rn_ybro;
 739 #endif
 740         t = tt->rn_p;
 741         if ((dupedkey = saved_tt->rn_dupedkey)) {
 742                 if (tt == saved_tt) {
 743                         x = dupedkey; x->rn_p = t;
 744                         if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x;
 745                 } else {
 746                         for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
 747                                 p = p->rn_dupedkey;
 748                         if (p) p->rn_dupedkey = tt->rn_dupedkey;
 749                         else log(LOG_ERR, "rn_delete: couldn't find us\n");
 750                 }
 751                 t = tt + 1;
 752                 if  (t->rn_flags & RNF_ACTIVE) {
 753 #ifndef RN_DEBUG
 754                         *++x = *t; p = t->rn_p;
 755 #else
 756                         b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p;
 757 #endif
 758                         if (p->rn_l == t) p->rn_l = x; else p->rn_r = x;
 759                         x->rn_l->rn_p = x; x->rn_r->rn_p = x;
 760                 }
 761                 goto out;
 762         }
 763         if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l;
 764         p = t->rn_p;
 765         if (p->rn_r == t) p->rn_r = x; else p->rn_l = x;
 766         x->rn_p = p;
 767         /*
 768          * Demote routes attached to us.
 769          */
 770         if (t->rn_mklist) {
 771                 if (x->rn_b >= 0) {
 772                         for (mp = &x->rn_mklist; (m = *mp);)
 773                                 mp = &m->rm_mklist;
 774                         *mp = t->rn_mklist;
 775                 } else {
 776                         /* If there are any key,mask pairs in a sibling
 777                            duped-key chain, some subset will appear sorted
 778                            in the same order attached to our mklist */
 779                         for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
 780                                 if (m == x->rn_mklist) {
 781                                         struct radix_mask *mm = m->rm_mklist;
 782                                         x->rn_mklist = 0;
 783                                         if (--(m->rm_refs) < 0)
 784                                                 MKFree(m);
 785                                         m = mm;
 786                                 }
 787                         if (m)
 788                                 syslog(LOG_ERR, "%s 0x%lx at 0x%lx\n",
 789                                        "rn_delete: Orphaned Mask",
 790                                        (unsigned long)m,
 791                                        (unsigned long)x);
 792                 }
 793         }
 794         /*
 795          * We may be holding an active internal node in the tree.
 796          */
 797         x = tt + 1;
 798         if (t != x) {
 799 #ifndef RN_DEBUG
 800                 *t = *x;
 801 #else
 802                 b = t->rn_info; *t = *x; t->rn_info = b;
 803 #endif
 804                 t->rn_l->rn_p = t; t->rn_r->rn_p = t;
 805                 p = x->rn_p;
 806                 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t;
 807         }
 808 out:
 809         tt->rn_flags &= ~RNF_ACTIVE;
 810         tt[1].rn_flags &= ~RNF_ACTIVE;
 811         return (tt);
 812 }
 813
 814 int
 815 rn_walktree(struct radix_node_head *h,
 816             int (*f)(struct radix_node *, struct walkarg *),
 817             struct walkarg *w)
 818 {
 819         int error;
 820         struct radix_node *base, *next;
 821         struct radix_node *rn = h->rnh_treetop;
 822         /*
 823          * This gets complicated because we may delete the node
 824          * while applying the function f to it, so we need to calculate
 825          * the successor node in advance.
 826          */
 827         /* First time through node, go left */
 828         while (rn->rn_b >= 0)
 829                 rn = rn->rn_l;
 830         for (;;) {
 831                 base = rn;
 832                 /* If at right child go back up, otherwise, go right */
 833                 while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0)
 834                         rn = rn->rn_p;
 835                 /* Find the next *leaf* since next node might vanish, too */
 836                 for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;)
 837                         rn = rn->rn_l;
 838                 next = rn;
 839                 /* Process leaves */
 840                 while ((rn = base)) {
 841                         base = rn->rn_dupedkey;
 842                         if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w)))
 843                                 return (error);
 844                 }
 845                 rn = next;
 846                 if (rn->rn_flags & RNF_ROOT)
 847                         return (0);
 848         }
 849         /* NOTREACHED */
 850 }
 851
 852 int
 853 rn_inithead(void **head, int off)
 854 {
 855         struct radix_node_head *rnh;
 856         struct radix_node *t, *tt, *ttt;
 857         if (*head)
 858                 return (1);
 859         rnh = (struct radix_node_head *)rtmalloc(sizeof(*rnh), "rn_inithead");
 860         Bzero(rnh, sizeof (*rnh));
 861         *head = rnh;
 862         t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
 863         ttt = rnh->rnh_nodes + 2;
 864         t->rn_r = ttt;
 865         t->rn_p = t;
 866         tt = t->rn_l;
 867         tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
 868         tt->rn_b = -1 - off;
 869         *ttt = *tt;
 870         ttt->rn_key = rn_ones;
 871         rnh->rnh_addaddr = rn_addroute;
 872         rnh->rnh_deladdr = rn_delete;
 873         rnh->rnh_matchaddr = rn_match;
 874         rnh->rnh_lookup = rn_lookup;
 875         rnh->rnh_walktree = rn_walktree;
 876         rnh->rnh_treetop = t;
 877         return (1);
 878 }
 879
 880 void
 881 rn_init(void)
 882 {
 883         char *cp, *cplim;
 884         if (max_keylen == 0) {
 885                 printf("rn_init: radix functions require max_keylen be set\n");
 886                 return;
 887         }
 888         rn_zeros = (char *)rtmalloc(3 * max_keylen, "rn_init");
 889         Bzero(rn_zeros, 3 * max_keylen);
 890         rn_ones = cp = rn_zeros + max_keylen;
 891         addmask_key = cplim = rn_ones + max_keylen;
 892         while (cp < cplim)
 893                 *cp++ = -1;
 894         if (rn_inithead((void *)&mask_rnhead, 0) == 0)
 895                 panic("rn_init 2");
 896 }
 897