1 /* 2 * Copyright (c) 1988, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 * 17 * @(#)radix.c 7.4 (Berkeley) 08/29/89 18 */ 19 20 /* 21 * Routines to build and maintain radix trees for routing lookups. 22 */ 23 #ifndef RNF_NORMAL 24 #include "param.h" 25 #include "radix.h" 26 #endif 27 struct radix_node_head *mask_rnhead; 28 #define rn_maskhead mask_rnhead->rnh_treetop 29 struct radix_mask *rn_mkfreelist; 30 struct radix_node_head *radix_node_head; 31 #undef Bcmp 32 #define Bcmp(a, b, l) (l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (u_long)l)) 33 /* 34 * The data structure for the keys is a radix tree with one way 35 * branching removed. The index rn_b at an internal node n represents a bit 36 * position to be tested. The tree is arranged so that all descendants 37 * of a node n have keys whose bits all agree up to position rn_b - 1. 38 * (We say the index of n is rn_b.) 39 * 40 * There is at least one descendant which has a one bit at position rn_b, 41 * and at least one with a zero there. 42 * 43 * A route is determined by a pair of key and mask. We require that the 44 * bit-wise logical and of the key and mask to be the key. 45 * We define the index of a route to associated with the mask to be 46 * the first bit number in the mask where 0 occurs (with bit number 0 47 * representing the highest order bit). 48 * 49 * We say a mask is normal if every bit is 0, past the index of the mask. 50 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b, 51 * and m is a normal mask, then the route applies to every descendant of n. 52 * If the index(m) < rn_b, this implies the trailing last few bits of k 53 * before bit b are all 0, (and hence consequently true of every descendant 54 * of n), so the route applies to all descendants of the node as well. 55 * 56 * The present version of the code makes no use of normal routes, 57 * but similar logic shows that a non-normal mask m such that 58 * index(m) <= index(n) could potentially apply to many children of n. 59 * Thus, for each non-host route, we attach its mask to a list at an internal 60 * node as high in the tree as we can go. 61 */ 62 63 struct radix_node * 64 rn_search(v, head) 65 struct radix_node *head; 66 register caddr_t v; 67 { 68 register struct radix_node *x; 69 70 for (x = head; x->rn_b >= 0;) { 71 if (x->rn_bmask & v[x->rn_off]) 72 x = x->rn_r; 73 else 74 x = x->rn_l; 75 } 76 return x; 77 }; 78 79 struct radix_node * 80 rn_search_m(v, head, m) 81 struct radix_node *head; 82 register caddr_t v, m; 83 { 84 register struct radix_node *x; 85 86 for (x = head; x->rn_b >= 0;) { 87 if ((x->rn_bmask & m[x->rn_off]) && 88 (x->rn_bmask & v[x->rn_off])) 89 x = x->rn_r; 90 else 91 x = x->rn_l; 92 } 93 return x; 94 }; 95 96 97 static int gotOddMasks; 98 static char maskedKey[MAXKEYLEN]; 99 100 struct radix_node * 101 rn_match(v, head) 102 struct radix_node *head; 103 caddr_t v; 104 { 105 register struct radix_node *t = head, *x; 106 register caddr_t cp = v, cp2, cp3; 107 caddr_t cplim, mstart; 108 struct radix_node *saved_t; 109 int off = t->rn_off, vlen = *(u_char *)cp, matched_off; 110 111 /* 112 * Open code rn_search(v, head) to avoid overhead of extra 113 * subroutine call. 114 */ 115 for (; t->rn_b >= 0; ) { 116 if (t->rn_bmask & cp[t->rn_off]) 117 t = t->rn_r; 118 else 119 t = t->rn_l; 120 } 121 /* 122 * See if we match exactly as a host destination 123 */ 124 cp += off; cp2 = t->rn_key + off; cplim = v + vlen; 125 for (; cp < cplim; cp++, cp2++) 126 if (*cp != *cp2) 127 goto on1; 128 /* 129 * This extra grot is in case we are explicitly asked 130 * to look up the default. Ugh! 131 */ 132 if ((t->rn_flags & RNF_ROOT) && t->rn_dupedkey) 133 t = t->rn_dupedkey; 134 return t; 135 on1: 136 matched_off = cp - v; 137 saved_t = t; 138 do { 139 if (t->rn_mask) { 140 /* 141 * Even if we don't match exactly as a hosts; 142 * we may match if the leaf we wound up at is 143 * a route to a net. 144 */ 145 cp3 = matched_off + t->rn_mask; 146 cp2 = matched_off + t->rn_key; 147 for (; cp < cplim; cp++) 148 if ((*cp2++ ^ *cp) & *cp3++) 149 break; 150 if (cp == cplim) 151 return t; 152 cp = matched_off + v; 153 } 154 } while (t = t->rn_dupedkey); 155 t = saved_t; 156 /* start searching up the tree */ 157 do { 158 register struct radix_mask *m; 159 t = t->rn_p; 160 if (m = t->rn_mklist) { 161 /* 162 * After doing measurements here, it may 163 * turn out to be faster to open code 164 * rn_search_m here instead of always 165 * copying and masking. 166 */ 167 off = min(t->rn_off, matched_off); 168 mstart = maskedKey + off; 169 do { 170 cp2 = mstart; 171 cp3 = m->rm_mask + off; 172 for (cp = v + off; cp < cplim;) 173 *cp2++ = *cp++ & *cp3++; 174 x = rn_search(maskedKey, t); 175 while (x && x->rn_mask != m->rm_mask) 176 x = x->rn_dupedkey; 177 if (x && 178 (Bcmp(mstart, x->rn_key + off, 179 vlen - off) == 0)) 180 return x; 181 } while (m = m->rm_mklist); 182 } 183 } while (t != head); 184 return 0; 185 }; 186 187 #ifdef RN_DEBUG 188 int rn_nodenum; 189 struct radix_node *rn_clist; 190 int rn_saveinfo; 191 #endif 192 193 struct radix_node * 194 rn_newpair(v, b, nodes) 195 caddr_t v; 196 struct radix_node nodes[2]; 197 { 198 register struct radix_node *tt = nodes, *t = tt + 1; 199 t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7); 200 t->rn_l = tt; t->rn_off = b >> 3; 201 tt->rn_b = -1; tt->rn_key = v; tt->rn_p = t; 202 tt->rn_flags = t->rn_flags = RNF_ACTIVE; 203 #ifdef RN_DEBUG 204 tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; 205 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; 206 #endif 207 return t; 208 } 209 210 int rn_debug = 1; 211 struct radix_node * 212 rn_insert(v, head, dupentry, nodes) 213 caddr_t v; 214 struct radix_node *head; 215 int *dupentry; 216 struct radix_node nodes[2]; 217 { 218 int head_off = head->rn_off, vlen = (int)*((u_char *)v); 219 register struct radix_node *t = rn_search(v, head); 220 register caddr_t cp = v + head_off; 221 register int b; 222 struct radix_node *tt; 223 /* 224 *find first bit at which v and t->rn_key differ 225 */ 226 { 227 register caddr_t cp2 = t->rn_key + head_off; 228 register int cmp_res; 229 caddr_t cplim = v + vlen; 230 231 while (cp < cplim) 232 if (*cp2++ != *cp++) 233 goto on1; 234 *dupentry = 1; 235 return t; 236 on1: 237 *dupentry = 0; 238 cmp_res = (cp[-1] ^ cp2[-1]) & 0xff; 239 for (b = (cp - v) << 3; cmp_res; b--) 240 cmp_res >>= 1; 241 } 242 { 243 register struct radix_node *p, *x = head; 244 cp = v; 245 do { 246 p = x; 247 if (cp[x->rn_off] & x->rn_bmask) 248 x = x->rn_r; 249 else x = x->rn_l; 250 } while (b > (unsigned) x->rn_b); /* x->rn_b < b && x->rn_b >= 0 */ 251 #ifdef RN_DEBUG 252 if (rn_debug) 253 printf("Going In:\n"), traverse(p); 254 #endif 255 t = rn_newpair(v, b, nodes); tt = t->rn_l; 256 if ((cp[p->rn_off] & p->rn_bmask) == 0) 257 p->rn_l = t; 258 else 259 p->rn_r = t; 260 x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */ 261 if ((cp[t->rn_off] & t->rn_bmask) == 0) { 262 t->rn_r = x; 263 } else { 264 t->rn_r = tt; t->rn_l = x; 265 } 266 #ifdef RN_DEBUG 267 if (rn_debug) 268 printf("Coming out:\n"), traverse(p); 269 #endif 270 } 271 return (tt); 272 } 273 274 struct radix_node * 275 rn_addroute(v, netmask, head, treenodes) 276 struct radix_node *head; 277 caddr_t netmask, v; 278 struct radix_node treenodes[2]; 279 { 280 register int j; 281 register caddr_t cp; 282 register struct radix_node *t, *x, *tt; 283 short b = 0, b_leaf; 284 int vlen = *(u_char *)v, maskduplicated = 0, mlen, keyduplicated; 285 caddr_t cplim; unsigned char *maskp; 286 struct radix_mask *m, **mp; 287 struct radix_node *saved_tt; 288 289 /* 290 * In dealing with non-contiguous masks, there may be 291 * many different routes which have the same mask. 292 * We will find it useful to have a unique pointer to 293 * the mask to speed avoiding duplicate references at 294 * nodes and possibly save time in calculating indices. 295 */ 296 if (netmask) { 297 x = rn_search(netmask, rn_maskhead); 298 mlen = *(u_char *)netmask; 299 if (Bcmp(netmask, x->rn_key, mlen) == 0) { 300 maskduplicated = 1; 301 netmask = x->rn_key; 302 b = -1 - x->rn_b; 303 } else { 304 maskduplicated = 0; 305 R_Malloc(x, struct radix_node *, MAXKEYLEN + 2 * sizeof (*x)); 306 if (x == 0) 307 return (0); 308 Bzero(x, MAXKEYLEN + 2 * sizeof (*x)); 309 cp = (caddr_t)(x + 2); 310 Bcopy(netmask, cp, mlen); 311 netmask = cp; 312 x = rn_insert(netmask, rn_maskhead, &maskduplicated, x); 313 /* 314 * Calculate index of mask. 315 */ 316 cplim = netmask + vlen; 317 for (cp = netmask + head->rn_off; cp < cplim; cp++) 318 if (*(u_char *)cp != 0xff) 319 break; 320 b = (cp - netmask) << 3; 321 if (cp != cplim) { 322 if (*cp != 0) { 323 gotOddMasks = 1; 324 for (j = 0x80; j; b++, j >>= 1) 325 if ((j & *cp) == 0) 326 break; 327 } 328 } 329 x->rn_b = -1 - b; 330 } 331 } 332 /* 333 * Deal with duplicated keys: attach node to previous instance 334 */ 335 saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes); 336 if (keyduplicated) { 337 do { 338 if (tt->rn_mask == netmask) 339 return (0); 340 t = tt; 341 } while (tt = tt->rn_dupedkey); 342 /* 343 * If the mask is not duplicated, we wouldn't 344 * find it among possible duplicate key entries 345 * anyway, so the above test doesn't hurt. 346 * 347 * XXX: we really ought to sort the masks 348 * for a duplicated key the same way as in a masklist. 349 * It is an unfortunate pain having to relocate 350 * the head of the list. 351 */ 352 t->rn_dupedkey = tt = treenodes; 353 #ifdef RN_DEBUG 354 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; 355 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; 356 #endif 357 t = saved_tt; 358 tt->rn_key = (caddr_t) v; 359 tt->rn_b = -1; 360 tt->rn_flags = t->rn_flags & ~RNF_ROOT; 361 } 362 /* 363 * Put mask in tree. 364 */ 365 if (netmask) { 366 tt->rn_mask = netmask; 367 tt->rn_b = x->rn_b; 368 } 369 t = saved_tt->rn_p; 370 b_leaf = -1 - t->rn_b; 371 if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r; 372 /* Promote general routes from below */ 373 if (x->rn_b < 0) { 374 if (x->rn_mask && (x->rn_b >= b_leaf)) { 375 MKGet(m); 376 if (m) { 377 Bzero(m, sizeof *m); 378 m->rm_b = x->rn_b; 379 m->rm_mask = x->rn_mask; 380 x->rn_mklist = t->rn_mklist = m; 381 } 382 } 383 } else if (x->rn_mklist) { 384 /* 385 * Skip over masks whose index is > that of new node 386 */ 387 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) 388 if (m->rm_b >= b_leaf) 389 break; 390 t->rn_mklist = m; *mp = 0; 391 } 392 /* Add new route to highest possible ancestor's list */ 393 if ((netmask == 0) || (b > t->rn_b )) 394 return tt; /* can't lift at all */ 395 b_leaf = tt->rn_b; 396 do { 397 x = t; 398 t = t->rn_p; 399 } while (b <= t->rn_b && x != head); 400 /* 401 * Search through routes associated with node to 402 * insert new route according to index. 403 * For nodes of equal index, place more specific 404 * masks first. 405 */ 406 cplim = netmask + mlen; 407 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) { 408 if (m->rm_b < b_leaf) 409 continue; 410 if (m->rm_b > b_leaf) 411 break; 412 if (m->rm_mask == netmask) { 413 m->rm_refs++; 414 tt->rn_mklist = m; 415 return tt; 416 } 417 maskp = (u_char *)m->rm_mask; 418 for (cp = netmask; cp < cplim; cp++) 419 if (*(u_char *)cp > *maskp++) 420 goto on2; 421 } 422 on2: 423 MKGet(m); 424 if (m == 0) { 425 printf("Mask for route not entered\n"); 426 return (tt); 427 } 428 Bzero(m, sizeof *m); 429 m->rm_b = b_leaf; 430 m->rm_mask = netmask; 431 m->rm_mklist = *mp; 432 *mp = m; 433 tt->rn_mklist = m; 434 return tt; 435 } 436 437 struct radix_node * 438 rn_delete(v, netmask, head) 439 caddr_t v, netmask; 440 struct radix_node *head; 441 { 442 register struct radix_node *t, *p, *x = head; 443 register struct radix_node *tt = rn_search(v, x); 444 int b, head_off = x->rn_off, vlen = * (u_char *) v; 445 struct radix_mask *m, *saved_m, **mp; 446 struct radix_node *dupedkey, *saved_tt = tt; 447 448 if (tt == 0 || 449 Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off)) 450 return (0); 451 /* 452 * Delete our route from mask lists. 453 */ 454 if (dupedkey = tt->rn_dupedkey) { 455 if (netmask) 456 netmask = rn_search(netmask, rn_maskhead)->rn_key; 457 for (; tt->rn_mask != netmask; tt = tt->rn_dupedkey) 458 if (tt == 0) 459 return (0); 460 } 461 if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0) 462 goto on1; 463 if (m->rm_mask != tt->rn_mask) { 464 printf("rn_delete: inconsistent annotation\n"); 465 goto on1; 466 } 467 if (--m->rm_refs >= 0) 468 goto on1; 469 b = -1 - tt->rn_b; 470 t = saved_tt->rn_p; 471 if (b > t->rn_b) 472 goto on1; /* Wasn't lifted at all */ 473 do { 474 x = t; 475 t = t->rn_p; 476 } while (b <= t->rn_b && x != head); 477 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) 478 if (m == saved_m) { 479 *mp = m->rm_mklist; 480 MKFree(m); 481 break; 482 } 483 if (m == 0) 484 printf("rn_delete: couldn't find our annotation\n"); 485 on1: 486 /* 487 * Eliminate us from tree 488 */ 489 if (tt->rn_flags & RNF_ROOT) 490 return (0); 491 #ifdef RN_DEBUG 492 /* Get us out of the creation list */ 493 for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {} 494 if (t) t->rn_ybro = tt->rn_ybro; 495 #endif RN_DEBUG 496 t = tt->rn_p; 497 if (dupedkey) { 498 if (tt == saved_tt) { 499 x = dupedkey; x->rn_p = t; 500 if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x; 501 #ifndef RN_DEBUG 502 x++; t = tt + 1; *x = *t; p = t->rn_p; 503 #else 504 x++; b = x->rn_info; t = tt + 1; *x = *t; p = t->rn_p; 505 x->rn_info = b; 506 #endif 507 if (p->rn_l == t) p->rn_l = x; else p->rn_r = x; 508 x->rn_l->rn_p = x; x->rn_r->rn_p = x; 509 } else { 510 for (p = saved_tt; p && p->rn_dupedkey != tt;) 511 p = p->rn_dupedkey; 512 if (p) p->rn_dupedkey = tt->rn_dupedkey; 513 else printf("rn_delete: couldn't find us\n"); 514 } 515 goto out; 516 } 517 if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l; 518 p = t->rn_p; 519 if (p->rn_r == t) p->rn_r = x; else p->rn_l = x; 520 x->rn_p = p; 521 /* 522 * Demote routes attached to us. 523 */ 524 if (t->rn_mklist) { 525 if (x->rn_b >= 0) { 526 if (m = x->rn_mklist) { 527 while (m->rm_mklist) 528 m = m->rm_mklist; 529 m->rm_mklist = t->rn_mklist; 530 } else 531 x->rn_mklist = m; 532 } else { 533 for (m = t->rn_mklist; m;) { 534 struct radix_mask *mm = m->rm_mklist; 535 if (m == x->rn_mklist && (--(m->rm_refs) < 0)) { 536 x->rn_mklist = 0; 537 MKFree(m); 538 } else 539 printf("rn_delete: Orphaned mask\n"); 540 m = mm; 541 } 542 } 543 } 544 /* 545 * We may be holding an active internal node in the tree. 546 */ 547 x = tt + 1; 548 if (t != x) { 549 #ifndef RN_DEBUG 550 *t = *x; 551 #else 552 b = t->rn_info; *t = *x; t->rn_info = b; 553 #endif 554 t->rn_l->rn_p = t; t->rn_r->rn_p = t; 555 p = x->rn_p; 556 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t; 557 } 558 out: 559 tt->rn_flags &= ~RNF_ACTIVE; 560 tt[1].rn_flags &= ~RNF_ACTIVE; 561 return (tt); 562 } 563 char rn_zeros[MAXKEYLEN], rn_ones[MAXKEYLEN]; 564 565 rn_inithead(head, off, af) 566 struct radix_node_head **head; 567 int off; 568 { 569 register struct radix_node_head *rnh; 570 register struct radix_node *t, *tt, *ttt; 571 if (*head) 572 return (1); 573 R_Malloc(rnh, struct radix_node_head *, sizeof (*rnh)); 574 if (rnh == 0) 575 return (0); 576 Bzero(rnh, sizeof (*rnh)); 577 *head = rnh; 578 t = rn_newpair(rn_zeros, off, rnh->rnh_nodes); 579 ttt = rnh->rnh_nodes + 2; 580 t->rn_r = ttt; 581 t->rn_p = t; 582 tt = t->rn_l; 583 tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE; 584 tt->rn_b = -1 - off; 585 *ttt = *tt; 586 ttt->rn_key = rn_ones; 587 rnh->rnh_af = af; 588 rnh->rnh_treetop = t; 589 if (radix_node_head == 0) { 590 caddr_t cp = rn_ones, cplim = rn_ones + MAXKEYLEN; 591 while (cp < cplim) 592 *cp++ = -1; 593 if (rn_inithead(&radix_node_head, 0, 0) == 0) { 594 Free(rnh); 595 *head = 0; 596 return (0); 597 } 598 mask_rnhead = radix_node_head; 599 } 600 rnh->rnh_next = radix_node_head->rnh_next; 601 if (radix_node_head != rnh) 602 radix_node_head->rnh_next = rnh; 603 return (1); 604 } 605