sbin/routed/radix.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgment:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)radix.c     8.4 (Berkeley) 11/2/94
  34  *
  35  * $FreeBSD: src/sbin/routed/radix.c,v 1.5 1999/09/05 17:49:11 peter Exp $
  36  * $DragonFly: src/sbin/routed/radix.c,v 1.3 2004/02/04 17:40:01 joerg Exp $
  37  */
  38
  39 /*
  40  * Routines to build and maintain radix trees for routing lookups.
  41  */
  42
  43 #include "defs.h"
  44
  45 #if !defined(sgi) && !defined(__NetBSD__)
  46 static char sccsid[] __attribute__((unused)) = "@(#)rdisc.c     8.1 (Berkeley) x/y/95";
  47 #elif defined(__NetBSD__)
  48 __RCSID("$NetBSD$");
  49 #endif
  50
  51 #define log(x, msg) syslog(x, msg)
  52 #define panic(s) {log(LOG_ERR,s); exit(1);}
  53 #define min(a,b) (((a)<(b))?(a):(b))
  54
  55 int     max_keylen;
  56 struct radix_mask *rn_mkfreelist;
  57 struct radix_node_head *mask_rnhead;
  58 static char *addmask_key;
  59 static char normal_chars[] = {0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, -1};
  60 static char *rn_zeros, *rn_ones;
  61
  62 #define rn_masktop (mask_rnhead->rnh_treetop)
  63 #undef Bcmp
  64 #define Bcmp(a, b, l) (l == 0 ? 0 \
  65                        : memcmp((caddr_t)(a), (caddr_t)(b), (size_t)l))
  66
  67 static int rn_satisfies_leaf(char *, struct radix_node *, int);
  68
  69 /*
  70  * The data structure for the keys is a radix tree with one way
  71  * branching removed.  The index rn_b at an internal node n represents a bit
  72  * position to be tested.  The tree is arranged so that all descendants
  73  * of a node n have keys whose bits all agree up to position rn_b - 1.
  74  * (We say the index of n is rn_b.)
  75  *
  76  * There is at least one descendant which has a one bit at position rn_b,
  77  * and at least one with a zero there.
  78  *
  79  * A route is determined by a pair of key and mask.  We require that the
  80  * bit-wise logical and of the key and mask to be the key.
  81  * We define the index of a route to associated with the mask to be
  82  * the first bit number in the mask where 0 occurs (with bit number 0
  83  * representing the highest order bit).
  84  *
  85  * We say a mask is normal if every bit is 0, past the index of the mask.
  86  * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b,
  87  * and m is a normal mask, then the route applies to every descendant of n.
  88  * If the index(m) < rn_b, this implies the trailing last few bits of k
  89  * before bit b are all 0, (and hence consequently true of every descendant
  90  * of n), so the route applies to all descendants of the node as well.
  91  *
  92  * Similar logic shows that a non-normal mask m such that
  93  * index(m) <= index(n) could potentially apply to many children of n.
  94  * Thus, for each non-host route, we attach its mask to a list at an internal
  95  * node as high in the tree as we can go.
  96  *
  97  * The present version of the code makes use of normal routes in short-
  98  * circuiting an explict mask and compare operation when testing whether
  99  * a key satisfies a normal route, and also in remembering the unique leaf
 100  * that governs a subtree.
 101  */
 102
 103 struct radix_node *
 104 rn_search(void *v_arg,
 105           struct radix_node *head)
 106 {
 107         struct radix_node *x;
 108         caddr_t v;
 109
 110         for (x = head, v = v_arg; x->rn_b >= 0;) {
 111                 if (x->rn_bmask & v[x->rn_off])
 112                         x = x->rn_r;
 113                 else
 114                         x = x->rn_l;
 115         }
 116         return (x);
 117 }
 118
 119 struct radix_node *
 120 rn_search_m(void *v_arg,
 121             struct radix_node *head,
 122             void *m_arg)
 123 {
 124         struct radix_node *x;
 125         caddr_t v = v_arg, m = m_arg;
 126
 127         for (x = head; x->rn_b >= 0;) {
 128                 if ((x->rn_bmask & m[x->rn_off]) &&
 129                     (x->rn_bmask & v[x->rn_off]))
 130                         x = x->rn_r;
 131                 else
 132                         x = x->rn_l;
 133         }
 134         return x;
 135 }
 136
 137 int
 138 rn_refines(void* m_arg, void *n_arg)
 139 {
 140         caddr_t m = m_arg, n = n_arg;
 141         caddr_t lim, lim2 = lim = n + *(u_char *)n;
 142         int longer = (*(u_char *)n++) - (int)(*(u_char *)m++);
 143         int masks_are_equal = 1;
 144
 145         if (longer > 0)
 146                 lim -= longer;
 147         while (n < lim) {
 148                 if (*n & ~(*m))
 149                         return 0;
 150                 if (*n++ != *m++)
 151                         masks_are_equal = 0;
 152         }
 153         while (n < lim2)
 154                 if (*n++)
 155                         return 0;
 156         if (masks_are_equal && (longer < 0))
 157                 for (lim2 = m - longer; m < lim2; )
 158                         if (*m++)
 159                                 return 1;
 160         return (!masks_are_equal);
 161 }
 162
 163 struct radix_node *
 164 rn_lookup(void *v_arg, void *m_arg, struct radix_node_head *head)
 165 {
 166         struct radix_node *x;
 167         caddr_t netmask = 0;
 168
 169         if (m_arg) {
 170                 if ((x = rn_addmask(m_arg, 1, head->rnh_treetop->rn_off)) == 0)
 171                         return (0);
 172                 netmask = x->rn_key;
 173         }
 174         x = rn_match(v_arg, head);
 175         if (x && netmask) {
 176                 while (x && x->rn_mask != netmask)
 177                         x = x->rn_dupedkey;
 178         }
 179         return x;
 180 }
 181
 182 static int
 183 rn_satisfies_leaf(char *trial,
 184                   struct radix_node *leaf,
 185                   int skip)
 186 {
 187         char *cp = trial, *cp2 = leaf->rn_key, *cp3 = leaf->rn_mask;
 188         char *cplim;
 189         int length = min(*(u_char *)cp, *(u_char *)cp2);
 190
 191         if (cp3 == 0)
 192                 cp3 = rn_ones;
 193         else
 194                 length = min(length, *(u_char *)cp3);
 195         cplim = cp + length; cp3 += skip; cp2 += skip;
 196         for (cp += skip; cp < cplim; cp++, cp2++, cp3++)
 197                 if ((*cp ^ *cp2) & *cp3)
 198                         return 0;
 199         return 1;
 200 }
 201
 202 struct radix_node *
 203 rn_match(void *v_arg,
 204          struct radix_node_head *head)
 205 {
 206         caddr_t v = v_arg;
 207         struct radix_node *t = head->rnh_treetop, *x;
 208         caddr_t cp = v, cp2;
 209         caddr_t cplim;
 210         struct radix_node *saved_t, *top = t;
 211         int off = t->rn_off, vlen = *(u_char *)cp, matched_off;
 212         int test, b, rn_b;
 213
 214         /*
 215          * Open code rn_search(v, top) to avoid overhead of extra
 216          * subroutine call.
 217          */
 218         for (; t->rn_b >= 0; ) {
 219                 if (t->rn_bmask & cp[t->rn_off])
 220                         t = t->rn_r;
 221                 else
 222                         t = t->rn_l;
 223         }
 224         /*
 225          * See if we match exactly as a host destination
 226          * or at least learn how many bits match, for normal mask finesse.
 227          *
 228          * It doesn't hurt us to limit how many bytes to check
 229          * to the length of the mask, since if it matches we had a genuine
 230          * match and the leaf we have is the most specific one anyway;
 231          * if it didn't match with a shorter length it would fail
 232          * with a long one.  This wins big for class B&C netmasks which
 233          * are probably the most common case...
 234          */
 235         if (t->rn_mask)
 236                 vlen = *(u_char *)t->rn_mask;
 237         cp += off; cp2 = t->rn_key + off; cplim = v + vlen;
 238         for (; cp < cplim; cp++, cp2++)
 239                 if (*cp != *cp2)
 240                         goto on1;
 241         /*
 242          * This extra grot is in case we are explicitly asked
 243          * to look up the default.  Ugh!
 244          * Or 255.255.255.255
 245          *
 246          * In this case, we have a complete match of the key.  Unless
 247          * the node is one of the roots, we are finished.
 248          * If it is the zeros root, then take what we have, prefering
 249          * any real data.
 250          * If it is the ones root, then pretend the target key was followed
 251          * by a byte of zeros.
 252          */
 253         if (!(t->rn_flags & RNF_ROOT))
 254                 return t;               /* not a root */
 255         if (t->rn_dupedkey) {
 256                 t = t->rn_dupedkey;
 257                 return t;               /* have some real data */
 258         }
 259         if (*(cp-1) == 0)
 260                 return t;               /* not the ones root */
 261         b = 0;                          /* fake a zero after 255.255.255.255 */
 262         goto on2;
 263 on1:
 264         test = (*cp ^ *cp2) & 0xff; /* find first bit that differs */
 265         for (b = 7; (test >>= 1) > 0;)
 266                 b--;
 267 on2:
 268         matched_off = cp - v;
 269         b += matched_off << 3;
 270         rn_b = -1 - b;
 271         /*
 272          * If there is a host route in a duped-key chain, it will be first.
 273          */
 274         if ((saved_t = t)->rn_mask == 0)
 275                 t = t->rn_dupedkey;
 276         for (; t; t = t->rn_dupedkey) {
 277                 /*
 278                  * Even if we don't match exactly as a host,
 279                  * we may match if the leaf we wound up at is
 280                  * a route to a net.
 281                  */
 282                 if (t->rn_flags & RNF_NORMAL) {
 283                         if (rn_b <= t->rn_b)
 284                                 return t;
 285                 } else if (rn_satisfies_leaf(v, t, matched_off)) {
 286                         return t;
 287                 }
 288         }
 289         t = saved_t;
 290         /* start searching up the tree */
 291         do {
 292                 struct radix_mask *m;
 293                 t = t->rn_p;
 294                 if ((m = t->rn_mklist)) {
 295                         /*
 296                          * If non-contiguous masks ever become important
 297                          * we can restore the masking and open coding of
 298                          * the search and satisfaction test and put the
 299                          * calculation of "off" back before the "do".
 300                          */
 301                         do {
 302                                 if (m->rm_flags & RNF_NORMAL) {
 303                                         if (rn_b <= m->rm_b)
 304                                                 return (m->rm_leaf);
 305                                 } else {
 306                                         off = min(t->rn_off, matched_off);
 307                                         x = rn_search_m(v, t, m->rm_mask);
 308                                         while (x && x->rn_mask != m->rm_mask)
 309                                                 x = x->rn_dupedkey;
 310                                         if (x && rn_satisfies_leaf(v, x, off))
 311                                                     return x;
 312                                 }
 313                         } while ((m = m->rm_mklist));
 314                 }
 315         } while (t != top);
 316         return 0;
 317 }
 318
 319 #ifdef RN_DEBUG
 320 int     rn_nodenum;
 321 struct  radix_node *rn_clist;
 322 int     rn_saveinfo;
 323 int     rn_debug =  1;
 324 #endif
 325
 326 struct radix_node *
 327 rn_newpair(void *v, int b, struct radix_node nodes[2])
 328 {
 329         struct radix_node *tt = nodes, *t = tt + 1;
 330         t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7);
 331         t->rn_l = tt; t->rn_off = b >> 3;
 332         tt->rn_b = -1; tt->rn_key = (caddr_t)v; tt->rn_p = t;
 333         tt->rn_flags = t->rn_flags = RNF_ACTIVE;
 334 #ifdef RN_DEBUG
 335         tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
 336         tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
 337 #endif
 338         return t;
 339 }
 340
 341 struct radix_node *
 342 rn_insert(void* v_arg,
 343           struct radix_node_head *head,
 344           int *dupentry,
 345           struct radix_node nodes[2])
 346 {
 347         caddr_t v = v_arg;
 348         struct radix_node *top = head->rnh_treetop;
 349         int head_off = top->rn_off, vlen = (int)*((u_char *)v);
 350         struct radix_node *t = rn_search(v_arg, top);
 351         caddr_t cp = v + head_off;
 352         int b;
 353         struct radix_node *tt;
 354
 355         /*
 356          * Find first bit at which v and t->rn_key differ
 357          */
 358     {
 359                 caddr_t cp2 = t->rn_key + head_off;
 360                 int cmp_res;
 361         caddr_t cplim = v + vlen;
 362
 363         while (cp < cplim)
 364                 if (*cp2++ != *cp++)
 365                         goto on1;
 366         /* handle adding 255.255.255.255 */
 367         if (!(t->rn_flags & RNF_ROOT) || *(cp2-1) == 0) {
 368                 *dupentry = 1;
 369                 return t;
 370         }
 371 on1:
 372         *dupentry = 0;
 373         cmp_res = (cp[-1] ^ cp2[-1]) & 0xff;
 374         for (b = (cp - v) << 3; cmp_res; b--)
 375                 cmp_res >>= 1;
 376     }
 377     {
 378             struct radix_node *p, *x = top;
 379         cp = v;
 380         do {
 381                 p = x;
 382                 if (cp[x->rn_off] & x->rn_bmask)
 383                         x = x->rn_r;
 384                 else x = x->rn_l;
 385         } while ((unsigned)b > (unsigned)x->rn_b);
 386 #ifdef RN_DEBUG
 387         if (rn_debug)
 388                 log(LOG_DEBUG, "rn_insert: Going In:\n"), traverse(p);
 389 #endif
 390         t = rn_newpair(v_arg, b, nodes); tt = t->rn_l;
 391         if ((cp[p->rn_off] & p->rn_bmask) == 0)
 392                 p->rn_l = t;
 393         else
 394                 p->rn_r = t;
 395         x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */
 396         if ((cp[t->rn_off] & t->rn_bmask) == 0) {
 397                 t->rn_r = x;
 398         } else {
 399                 t->rn_r = tt; t->rn_l = x;
 400         }
 401 #ifdef RN_DEBUG
 402         if (rn_debug)
 403                 log(LOG_DEBUG, "rn_insert: Coming Out:\n"), traverse(p);
 404 #endif
 405     }
 406         return (tt);
 407 }
 408
 409 struct radix_node *
 410 rn_addmask(void *n_arg, int search, int skip)
 411 {
 412         caddr_t netmask = (caddr_t)n_arg;
 413         struct radix_node *x;
 414         caddr_t cp, cplim;
 415         int b = 0, mlen, j;
 416         int maskduplicated, m0, isnormal;
 417         struct radix_node *saved_x;
 418         static int last_zeroed = 0;
 419
 420         if ((mlen = *(u_char *)netmask) > max_keylen)
 421                 mlen = max_keylen;
 422         if (skip == 0)
 423                 skip = 1;
 424         if (mlen <= skip)
 425                 return (mask_rnhead->rnh_nodes);
 426         if (skip > 1)
 427                 Bcopy(rn_ones + 1, addmask_key + 1, skip - 1);
 428         if ((m0 = mlen) > skip)
 429                 Bcopy(netmask + skip, addmask_key + skip, mlen - skip);
 430         /*
 431          * Trim trailing zeroes.
 432          */
 433         for (cp = addmask_key + mlen; (cp > addmask_key) && cp[-1] == 0;)
 434                 cp--;
 435         mlen = cp - addmask_key;
 436         if (mlen <= skip) {
 437                 if (m0 >= last_zeroed)
 438                         last_zeroed = mlen;
 439                 return (mask_rnhead->rnh_nodes);
 440         }
 441         if (m0 < last_zeroed)
 442                 Bzero(addmask_key + m0, last_zeroed - m0);
 443         *addmask_key = last_zeroed = mlen;
 444         x = rn_search(addmask_key, rn_masktop);
 445         if (Bcmp(addmask_key, x->rn_key, mlen) != 0)
 446                 x = 0;
 447         if (x || search)
 448                 return (x);
 449         x = (struct radix_node *)rtmalloc(max_keylen + 2*sizeof(*x),
 450                                           "rn_addmask");
 451         saved_x = x;
 452         Bzero(x, max_keylen + 2 * sizeof (*x));
 453         netmask = cp = (caddr_t)(x + 2);
 454         Bcopy(addmask_key, cp, mlen);
 455         x = rn_insert(cp, mask_rnhead, &maskduplicated, x);
 456         if (maskduplicated) {
 457                 log(LOG_ERR, "rn_addmask: mask impossibly already in tree");
 458                 Free(saved_x);
 459                 return (x);
 460         }
 461         /*
 462          * Calculate index of mask, and check for normalcy.
 463          */
 464         cplim = netmask + mlen; isnormal = 1;
 465         for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
 466                 cp++;
 467         if (cp != cplim) {
 468                 for (j = 0x80; (j & *cp) != 0; j >>= 1)
 469                         b++;
 470                 if (*cp != normal_chars[b] || cp != (cplim - 1))
 471                         isnormal = 0;
 472         }
 473         b += (cp - netmask) << 3;
 474         x->rn_b = -1 - b;
 475         if (isnormal)
 476                 x->rn_flags |= RNF_NORMAL;
 477         return (x);
 478 }
 479
 480 static int      /* XXX: arbitrary ordering for non-contiguous masks */
 481 rn_lexobetter(void *m_arg, void *n_arg)
 482 {
 483         u_char *mp = m_arg, *np = n_arg, *lim;
 484
 485         if (*mp > *np)
 486                 return 1;  /* not really, but need to check longer one first */
 487         if (*mp == *np)
 488                 for (lim = mp + *mp; mp < lim;)
 489                         if (*mp++ > *np++)
 490                                 return 1;
 491         return 0;
 492 }
 493
 494 static struct radix_mask *
 495 rn_new_radix_mask(struct radix_node *tt,
 496                   struct radix_mask *next)
 497 {
 498         struct radix_mask *m;
 499
 500         MKGet(m);
 501         if (m == 0) {
 502                 log(LOG_ERR, "Mask for route not entered\n");
 503                 return (0);
 504         }
 505         Bzero(m, sizeof *m);
 506         m->rm_b = tt->rn_b;
 507         m->rm_flags = tt->rn_flags;
 508         if (tt->rn_flags & RNF_NORMAL)
 509                 m->rm_leaf = tt;
 510         else
 511                 m->rm_mask = tt->rn_mask;
 512         m->rm_mklist = next;
 513         tt->rn_mklist = m;
 514         return m;
 515 }
 516
 517 struct radix_node *
 518 rn_addroute(void *v_arg,
 519             void *n_arg,
 520             struct radix_node_head *head,
 521             struct radix_node treenodes[2])
 522 {
 523         caddr_t v = (caddr_t)v_arg, netmask = (caddr_t)n_arg;
 524         struct radix_node *t, *x = 0, *tt;
 525         struct radix_node *saved_tt, *top = head->rnh_treetop;
 526         short b = 0, b_leaf = 0;
 527         int keyduplicated;
 528         caddr_t mmask;
 529         struct radix_mask *m, **mp;
 530
 531         /*
 532          * In dealing with non-contiguous masks, there may be
 533          * many different routes which have the same mask.
 534          * We will find it useful to have a unique pointer to
 535          * the mask to speed avoiding duplicate references at
 536          * nodes and possibly save time in calculating indices.
 537          */
 538         if (netmask)  {
 539                 if ((x = rn_addmask(netmask, 0, top->rn_off)) == 0)
 540                         return (0);
 541                 b_leaf = x->rn_b;
 542                 b = -1 - x->rn_b;
 543                 netmask = x->rn_key;
 544         }
 545         /*
 546          * Deal with duplicated keys: attach node to previous instance
 547          */
 548         saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes);
 549         if (keyduplicated) {
 550                 for (t = tt; tt; t = tt, tt = tt->rn_dupedkey) {
 551                         if (tt->rn_mask == netmask)
 552                                 return (0);
 553                         if (netmask == 0 ||
 554                             (tt->rn_mask &&
 555                              ((b_leaf < tt->rn_b) || /* index(netmask) > node */
 556                                rn_refines(netmask, tt->rn_mask) ||
 557                                rn_lexobetter(netmask, tt->rn_mask))))
 558                                 break;
 559                 }
 560                 /*
 561                  * If the mask is not duplicated, we wouldn't
 562                  * find it among possible duplicate key entries
 563                  * anyway, so the above test doesn't hurt.
 564                  *
 565                  * We sort the masks for a duplicated key the same way as
 566                  * in a masklist -- most specific to least specific.
 567                  * This may require the unfortunate nuisance of relocating
 568                  * the head of the list.
 569                  */
 570                 if (tt == saved_tt) {
 571                         struct  radix_node *xx = x;
 572                         /* link in at head of list */
 573                         (tt = treenodes)->rn_dupedkey = t;
 574                         tt->rn_flags = t->rn_flags;
 575                         tt->rn_p = x = t->rn_p;
 576                         if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt;
 577                         saved_tt = tt; x = xx;
 578                 } else {
 579                         (tt = treenodes)->rn_dupedkey = t->rn_dupedkey;
 580                         t->rn_dupedkey = tt;
 581                 }
 582 #ifdef RN_DEBUG
 583                 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++;
 584                 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt;
 585 #endif
 586                 tt->rn_key = (caddr_t) v;
 587                 tt->rn_b = -1;
 588                 tt->rn_flags = RNF_ACTIVE;
 589         }
 590         /*
 591          * Put mask in tree.
 592          */
 593         if (netmask) {
 594                 tt->rn_mask = netmask;
 595                 tt->rn_b = x->rn_b;
 596                 tt->rn_flags |= x->rn_flags & RNF_NORMAL;
 597         }
 598         t = saved_tt->rn_p;
 599         if (keyduplicated)
 600                 goto on2;
 601         b_leaf = -1 - t->rn_b;
 602         if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r;
 603         /* Promote general routes from below */
 604         if (x->rn_b < 0) {
 605             for (mp = &t->rn_mklist; x; x = x->rn_dupedkey)
 606                 if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) {
 607                         if ((*mp = m = rn_new_radix_mask(x, 0)))
 608                                 mp = &m->rm_mklist;
 609                 }
 610         } else if (x->rn_mklist) {
 611                 /*
 612                  * Skip over masks whose index is > that of new node
 613                  */
 614                 for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
 615                         if (m->rm_b >= b_leaf)
 616                                 break;
 617                 t->rn_mklist = m; *mp = 0;
 618         }
 619 on2:
 620         /* Add new route to highest possible ancestor's list */
 621         if ((netmask == 0) || (b > t->rn_b ))
 622                 return tt; /* can't lift at all */
 623         b_leaf = tt->rn_b;
 624         do {
 625                 x = t;
 626                 t = t->rn_p;
 627         } while (b <= t->rn_b && x != top);
 628         /*
 629          * Search through routes associated with node to
 630          * insert new route according to index.
 631          * Need same criteria as when sorting dupedkeys to avoid
 632          * double loop on deletion.
 633          */
 634         for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist) {
 635                 if (m->rm_b < b_leaf)
 636                         continue;
 637                 if (m->rm_b > b_leaf)
 638                         break;
 639                 if (m->rm_flags & RNF_NORMAL) {
 640                         mmask = m->rm_leaf->rn_mask;
 641                         if (tt->rn_flags & RNF_NORMAL) {
 642                                 log(LOG_ERR,
 643                                    "Non-unique normal route, mask not entered");
 644                                 return tt;
 645                         }
 646                 } else
 647                         mmask = m->rm_mask;
 648                 if (mmask == netmask) {
 649                         m->rm_refs++;
 650                         tt->rn_mklist = m;
 651                         return tt;
 652                 }
 653                 if (rn_refines(netmask, mmask) || rn_lexobetter(netmask, mmask))
 654                         break;
 655         }
 656         *mp = rn_new_radix_mask(tt, *mp);
 657         return tt;
 658 }
 659
 660 struct radix_node *
 661 rn_delete(void *v_arg,
 662           void *netmask_arg,
 663           struct radix_node_head *head)
 664 {
 665         struct radix_node *t, *p, *x, *tt;
 666         struct radix_mask *m, *saved_m, **mp;
 667         struct radix_node *dupedkey, *saved_tt, *top;
 668         caddr_t v, netmask;
 669         int b, head_off, vlen;
 670
 671         v = v_arg;
 672         netmask = netmask_arg;
 673         x = head->rnh_treetop;
 674         tt = rn_search(v, x);
 675         head_off = x->rn_off;
 676         vlen =  *(u_char *)v;
 677         saved_tt = tt;
 678         top = x;
 679         if (tt == 0 ||
 680             Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off))
 681                 return (0);
 682         /*
 683          * Delete our route from mask lists.
 684          */
 685         if (netmask) {
 686                 if ((x = rn_addmask(netmask, 1, head_off)) == 0)
 687                         return (0);
 688                 netmask = x->rn_key;
 689                 while (tt->rn_mask != netmask)
 690                         if ((tt = tt->rn_dupedkey) == 0)
 691                                 return (0);
 692         }
 693         if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0)
 694                 goto on1;
 695         if (tt->rn_flags & RNF_NORMAL) {
 696                 if (m->rm_leaf != tt || m->rm_refs > 0) {
 697                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
 698                         return 0;  /* dangling ref could cause disaster */
 699                 }
 700         } else {
 701                 if (m->rm_mask != tt->rn_mask) {
 702                         log(LOG_ERR, "rn_delete: inconsistent annotation\n");
 703                         goto on1;
 704                 }
 705                 if (--m->rm_refs >= 0)
 706                         goto on1;
 707         }
 708         b = -1 - tt->rn_b;
 709         t = saved_tt->rn_p;
 710         if (b > t->rn_b)
 711                 goto on1; /* Wasn't lifted at all */
 712         do {
 713                 x = t;
 714                 t = t->rn_p;
 715         } while (b <= t->rn_b && x != top);
 716         for (mp = &x->rn_mklist; (m = *mp); mp = &m->rm_mklist)
 717                 if (m == saved_m) {
 718                         *mp = m->rm_mklist;
 719                         MKFree(m);
 720                         break;
 721                 }
 722         if (m == 0) {
 723                 log(LOG_ERR, "rn_delete: couldn't find our annotation\n");
 724                 if (tt->rn_flags & RNF_NORMAL)
 725                         return (0); /* Dangling ref to us */
 726         }
 727 on1:
 728         /*
 729          * Eliminate us from tree
 730          */
 731         if (tt->rn_flags & RNF_ROOT)
 732                 return (0);
 733 #ifdef RN_DEBUG
 734         /* Get us out of the creation list */
 735         for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {}
 736         if (t) t->rn_ybro = tt->rn_ybro;
 737 #endif
 738         t = tt->rn_p;
 739         if ((dupedkey = saved_tt->rn_dupedkey)) {
 740                 if (tt == saved_tt) {
 741                         x = dupedkey; x->rn_p = t;
 742                         if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x;
 743                 } else {
 744                         for (x = p = saved_tt; p && p->rn_dupedkey != tt;)
 745                                 p = p->rn_dupedkey;
 746                         if (p) p->rn_dupedkey = tt->rn_dupedkey;
 747                         else log(LOG_ERR, "rn_delete: couldn't find us\n");
 748                 }
 749                 t = tt + 1;
 750                 if  (t->rn_flags & RNF_ACTIVE) {
 751 #ifndef RN_DEBUG
 752                         *++x = *t; p = t->rn_p;
 753 #else
 754                         b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p;
 755 #endif
 756                         if (p->rn_l == t) p->rn_l = x; else p->rn_r = x;
 757                         x->rn_l->rn_p = x; x->rn_r->rn_p = x;
 758                 }
 759                 goto out;
 760         }
 761         if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l;
 762         p = t->rn_p;
 763         if (p->rn_r == t) p->rn_r = x; else p->rn_l = x;
 764         x->rn_p = p;
 765         /*
 766          * Demote routes attached to us.
 767          */
 768         if (t->rn_mklist) {
 769                 if (x->rn_b >= 0) {
 770                         for (mp = &x->rn_mklist; (m = *mp);)
 771                                 mp = &m->rm_mklist;
 772                         *mp = t->rn_mklist;
 773                 } else {
 774                         /* If there are any key,mask pairs in a sibling
 775                            duped-key chain, some subset will appear sorted
 776                            in the same order attached to our mklist */
 777                         for (m = t->rn_mklist; m && x; x = x->rn_dupedkey)
 778                                 if (m == x->rn_mklist) {
 779                                         struct radix_mask *mm = m->rm_mklist;
 780                                         x->rn_mklist = 0;
 781                                         if (--(m->rm_refs) < 0)
 782                                                 MKFree(m);
 783                                         m = mm;
 784                                 }
 785                         if (m)
 786                                 syslog(LOG_ERR, "%s 0x%lx at 0x%lx\n",
 787                                        "rn_delete: Orphaned Mask",
 788                                        (unsigned long)m,
 789                                        (unsigned long)x);
 790                 }
 791         }
 792         /*
 793          * We may be holding an active internal node in the tree.
 794          */
 795         x = tt + 1;
 796         if (t != x) {
 797 #ifndef RN_DEBUG
 798                 *t = *x;
 799 #else
 800                 b = t->rn_info; *t = *x; t->rn_info = b;
 801 #endif
 802                 t->rn_l->rn_p = t; t->rn_r->rn_p = t;
 803                 p = x->rn_p;
 804                 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t;
 805         }
 806 out:
 807         tt->rn_flags &= ~RNF_ACTIVE;
 808         tt[1].rn_flags &= ~RNF_ACTIVE;
 809         return (tt);
 810 }
 811
 812 int
 813 rn_walktree(struct radix_node_head *h,
 814             int (*f)(struct radix_node *, struct walkarg *),
 815             struct walkarg *w)
 816 {
 817         int error;
 818         struct radix_node *base, *next;
 819         struct radix_node *rn = h->rnh_treetop;
 820         /*
 821          * This gets complicated because we may delete the node
 822          * while applying the function f to it, so we need to calculate
 823          * the successor node in advance.
 824          */
 825         /* First time through node, go left */
 826         while (rn->rn_b >= 0)
 827                 rn = rn->rn_l;
 828         for (;;) {
 829                 base = rn;
 830                 /* If at right child go back up, otherwise, go right */
 831                 while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0)
 832                         rn = rn->rn_p;
 833                 /* Find the next *leaf* since next node might vanish, too */
 834                 for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;)
 835                         rn = rn->rn_l;
 836                 next = rn;
 837                 /* Process leaves */
 838                 while ((rn = base)) {
 839                         base = rn->rn_dupedkey;
 840                         if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w)))
 841                                 return (error);
 842                 }
 843                 rn = next;
 844                 if (rn->rn_flags & RNF_ROOT)
 845                         return (0);
 846         }
 847         /* NOTREACHED */
 848 }
 849
 850 int
 851 rn_inithead(struct radix_node_head **head, int off)
 852 {
 853         struct radix_node_head *rnh;
 854         struct radix_node *t, *tt, *ttt;
 855         if (*head)
 856                 return (1);
 857         rnh = (struct radix_node_head *)rtmalloc(sizeof(*rnh), "rn_inithead");
 858         Bzero(rnh, sizeof (*rnh));
 859         *head = rnh;
 860         t = rn_newpair(rn_zeros, off, rnh->rnh_nodes);
 861         ttt = rnh->rnh_nodes + 2;
 862         t->rn_r = ttt;
 863         t->rn_p = t;
 864         tt = t->rn_l;
 865         tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE;
 866         tt->rn_b = -1 - off;
 867         *ttt = *tt;
 868         ttt->rn_key = rn_ones;
 869         rnh->rnh_addaddr = rn_addroute;
 870         rnh->rnh_deladdr = rn_delete;
 871         rnh->rnh_matchaddr = rn_match;
 872         rnh->rnh_lookup = rn_lookup;
 873         rnh->rnh_walktree = rn_walktree;
 874         rnh->rnh_treetop = t;
 875         return (1);
 876 }
 877
 878 void
 879 rn_init(void)
 880 {
 881         char *cp, *cplim;
 882         if (max_keylen == 0) {
 883                 printf("rn_init: radix functions require max_keylen be set\n");
 884                 return;
 885         }
 886         rn_zeros = (char *)rtmalloc(3 * max_keylen, "rn_init");
 887         Bzero(rn_zeros, 3 * max_keylen);
 888         rn_ones = cp = rn_zeros + max_keylen;
 889         addmask_key = cplim = rn_ones + max_keylen;
 890         while (cp < cplim)
 891                 *cp++ = -1;
 892         if (rn_inithead(&mask_rnhead, 0) == 0)
 893                 panic("rn_init 2");
 894 }
 895