1 /* 2 * Copyright (c) 1988, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)radix.c 7.12 (Berkeley) 08/08/91 8 */ 9 10 /* 11 * Routines to build and maintain radix trees for routing lookups. 12 */ 13 #ifndef RNF_NORMAL 14 #include "param.h" 15 #include "radix.h" 16 #include "malloc.h" 17 #define M_DONTWAIT M_NOWAIT 18 #endif 19 struct radix_mask *rn_mkfreelist; 20 struct radix_node_head *mask_rnhead; 21 #define rn_maskhead (mask_rnhead->rnh_treetop) 22 #undef Bcmp 23 #define Bcmp(a, b, l) (l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (u_long)l)) 24 /* 25 * The data structure for the keys is a radix tree with one way 26 * branching removed. The index rn_b at an internal node n represents a bit 27 * position to be tested. The tree is arranged so that all descendants 28 * of a node n have keys whose bits all agree up to position rn_b - 1. 29 * (We say the index of n is rn_b.) 30 * 31 * There is at least one descendant which has a one bit at position rn_b, 32 * and at least one with a zero there. 33 * 34 * A route is determined by a pair of key and mask. We require that the 35 * bit-wise logical and of the key and mask to be the key. 36 * We define the index of a route to associated with the mask to be 37 * the first bit number in the mask where 0 occurs (with bit number 0 38 * representing the highest order bit). 39 * 40 * We say a mask is normal if every bit is 0, past the index of the mask. 41 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b, 42 * and m is a normal mask, then the route applies to every descendant of n. 43 * If the index(m) < rn_b, this implies the trailing last few bits of k 44 * before bit b are all 0, (and hence consequently true of every descendant 45 * of n), so the route applies to all descendants of the node as well. 46 * 47 * The present version of the code makes no use of normal routes, 48 * but similar logic shows that a non-normal mask m such that 49 * index(m) <= index(n) could potentially apply to many children of n. 50 * Thus, for each non-host route, we attach its mask to a list at an internal 51 * node as high in the tree as we can go. 52 */ 53 54 struct radix_node * 55 rn_search(v, head) 56 struct radix_node *head; 57 register caddr_t v; 58 { 59 register struct radix_node *x; 60 61 for (x = head; x->rn_b >= 0;) { 62 if (x->rn_bmask & v[x->rn_off]) 63 x = x->rn_r; 64 else 65 x = x->rn_l; 66 } 67 return x; 68 }; 69 70 struct radix_node * 71 rn_search_m(v, head, m) 72 struct radix_node *head; 73 register caddr_t v, m; 74 { 75 register struct radix_node *x; 76 77 for (x = head; x->rn_b >= 0;) { 78 if ((x->rn_bmask & m[x->rn_off]) && 79 (x->rn_bmask & v[x->rn_off])) 80 x = x->rn_r; 81 else 82 x = x->rn_l; 83 } 84 return x; 85 }; 86 87 rn_refines(m, n) 88 register caddr_t m, n; 89 { 90 register caddr_t lim, lim2 = lim = n + *(u_char *)n; 91 int longer = (*(u_char *)n++) - (int)(*(u_char *)m++); 92 93 if (longer > 0) 94 lim -= longer; 95 while (n < lim) 96 if (*n++ & ~(*m++)) 97 return 0; 98 while (n < lim2) 99 if (*n++) 100 return 0; 101 return 1; 102 } 103 104 105 #define MAXKEYLEN 52 106 static int gotOddMasks; 107 static char maskedKey[MAXKEYLEN]; 108 109 struct radix_node * 110 rn_match(v, head) 111 struct radix_node *head; 112 caddr_t v; 113 { 114 register struct radix_node *t = head, *x; 115 register caddr_t cp = v, cp2, cp3; 116 caddr_t cplim, mstart; 117 struct radix_node *saved_t; 118 int off = t->rn_off, vlen = *(u_char *)cp, matched_off; 119 120 /* 121 * Open code rn_search(v, head) to avoid overhead of extra 122 * subroutine call. 123 */ 124 for (; t->rn_b >= 0; ) { 125 if (t->rn_bmask & cp[t->rn_off]) 126 t = t->rn_r; 127 else 128 t = t->rn_l; 129 } 130 /* 131 * See if we match exactly as a host destination 132 */ 133 cp += off; cp2 = t->rn_key + off; cplim = v + vlen; 134 for (; cp < cplim; cp++, cp2++) 135 if (*cp != *cp2) 136 goto on1; 137 /* 138 * This extra grot is in case we are explicitly asked 139 * to look up the default. Ugh! 140 */ 141 if ((t->rn_flags & RNF_ROOT) && t->rn_dupedkey) 142 t = t->rn_dupedkey; 143 return t; 144 on1: 145 matched_off = cp - v; 146 saved_t = t; 147 do { 148 if (t->rn_mask) { 149 /* 150 * Even if we don't match exactly as a hosts; 151 * we may match if the leaf we wound up at is 152 * a route to a net. 153 */ 154 cp3 = matched_off + t->rn_mask; 155 cp2 = matched_off + t->rn_key; 156 for (; cp < cplim; cp++) 157 if ((*cp2++ ^ *cp) & *cp3++) 158 break; 159 if (cp == cplim) 160 return t; 161 cp = matched_off + v; 162 } 163 } while (t = t->rn_dupedkey); 164 t = saved_t; 165 /* start searching up the tree */ 166 do { 167 register struct radix_mask *m; 168 t = t->rn_p; 169 if (m = t->rn_mklist) { 170 /* 171 * After doing measurements here, it may 172 * turn out to be faster to open code 173 * rn_search_m here instead of always 174 * copying and masking. 175 */ 176 off = min(t->rn_off, matched_off); 177 mstart = maskedKey + off; 178 do { 179 cp2 = mstart; 180 cp3 = m->rm_mask + off; 181 for (cp = v + off; cp < cplim;) 182 *cp2++ = *cp++ & *cp3++; 183 x = rn_search(maskedKey, t); 184 while (x && x->rn_mask != m->rm_mask) 185 x = x->rn_dupedkey; 186 if (x && 187 (Bcmp(mstart, x->rn_key + off, 188 vlen - off) == 0)) 189 return x; 190 } while (m = m->rm_mklist); 191 } 192 } while (t != head); 193 return 0; 194 }; 195 196 #ifdef RN_DEBUG 197 int rn_nodenum; 198 struct radix_node *rn_clist; 199 int rn_saveinfo; 200 #endif 201 202 struct radix_node * 203 rn_newpair(v, b, nodes) 204 caddr_t v; 205 struct radix_node nodes[2]; 206 { 207 register struct radix_node *tt = nodes, *t = tt + 1; 208 t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7); 209 t->rn_l = tt; t->rn_off = b >> 3; 210 tt->rn_b = -1; tt->rn_key = v; tt->rn_p = t; 211 tt->rn_flags = t->rn_flags = RNF_ACTIVE; 212 #ifdef RN_DEBUG 213 tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; 214 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; 215 #endif 216 return t; 217 } 218 219 int rn_debug = 1; 220 struct radix_node * 221 rn_insert(v, head, dupentry, nodes) 222 caddr_t v; 223 struct radix_node *head; 224 int *dupentry; 225 struct radix_node nodes[2]; 226 { 227 int head_off = head->rn_off, vlen = (int)*((u_char *)v); 228 register struct radix_node *t = rn_search(v, head); 229 register caddr_t cp = v + head_off; 230 register int b; 231 struct radix_node *tt; 232 /* 233 *find first bit at which v and t->rn_key differ 234 */ 235 { 236 register caddr_t cp2 = t->rn_key + head_off; 237 register int cmp_res; 238 caddr_t cplim = v + vlen; 239 240 while (cp < cplim) 241 if (*cp2++ != *cp++) 242 goto on1; 243 *dupentry = 1; 244 return t; 245 on1: 246 *dupentry = 0; 247 cmp_res = (cp[-1] ^ cp2[-1]) & 0xff; 248 for (b = (cp - v) << 3; cmp_res; b--) 249 cmp_res >>= 1; 250 } 251 { 252 register struct radix_node *p, *x = head; 253 cp = v; 254 do { 255 p = x; 256 if (cp[x->rn_off] & x->rn_bmask) 257 x = x->rn_r; 258 else x = x->rn_l; 259 } while (b > (unsigned) x->rn_b); /* x->rn_b < b && x->rn_b >= 0 */ 260 #ifdef RN_DEBUG 261 if (rn_debug) 262 printf("Going In:\n"), traverse(p); 263 #endif 264 t = rn_newpair(v, b, nodes); tt = t->rn_l; 265 if ((cp[p->rn_off] & p->rn_bmask) == 0) 266 p->rn_l = t; 267 else 268 p->rn_r = t; 269 x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */ 270 if ((cp[t->rn_off] & t->rn_bmask) == 0) { 271 t->rn_r = x; 272 } else { 273 t->rn_r = tt; t->rn_l = x; 274 } 275 #ifdef RN_DEBUG 276 if (rn_debug) 277 printf("Coming out:\n"), traverse(p); 278 #endif 279 } 280 return (tt); 281 } 282 283 struct radix_node * 284 rn_addmask(netmask, search, skip) 285 caddr_t netmask; 286 { 287 register struct radix_node *x; 288 register caddr_t cp, cplim; 289 register int b, mlen, j; 290 int maskduplicated; 291 292 mlen = *(u_char *)netmask; 293 if (search) { 294 x = rn_search(netmask, rn_maskhead); 295 mlen = *(u_char *)netmask; 296 if (Bcmp(netmask, x->rn_key, mlen) == 0) 297 return (x); 298 } 299 R_Malloc(x, struct radix_node *, MAXKEYLEN + 2 * sizeof (*x)); 300 if (x == 0) 301 return (0); 302 Bzero(x, MAXKEYLEN + 2 * sizeof (*x)); 303 cp = (caddr_t)(x + 2); 304 Bcopy(netmask, cp, mlen); 305 netmask = cp; 306 x = rn_insert(netmask, rn_maskhead, &maskduplicated, x); 307 /* 308 * Calculate index of mask. 309 */ 310 cplim = netmask + mlen; 311 for (cp = netmask + skip; cp < cplim; cp++) 312 if (*(u_char *)cp != 0xff) 313 break; 314 b = (cp - netmask) << 3; 315 if (cp != cplim) { 316 if (*cp != 0) { 317 gotOddMasks = 1; 318 for (j = 0x80; j; b++, j >>= 1) 319 if ((j & *cp) == 0) 320 break; 321 } 322 } 323 x->rn_b = -1 - b; 324 return (x); 325 } 326 327 struct radix_node * 328 rn_addroute(v, netmask, head, treenodes) 329 struct radix_node *head; 330 caddr_t netmask, v; 331 struct radix_node treenodes[2]; 332 { 333 register int j; 334 register caddr_t cp; 335 register struct radix_node *t, *x, *tt; 336 short b = 0, b_leaf; 337 int vlen = *(u_char *)v, mlen, keyduplicated; 338 caddr_t cplim; unsigned char *maskp; 339 struct radix_mask *m, **mp; 340 struct radix_node *saved_tt; 341 342 /* 343 * In dealing with non-contiguous masks, there may be 344 * many different routes which have the same mask. 345 * We will find it useful to have a unique pointer to 346 * the mask to speed avoiding duplicate references at 347 * nodes and possibly save time in calculating indices. 348 */ 349 if (netmask) { 350 x = rn_search(netmask, rn_maskhead); 351 mlen = *(u_char *)netmask; 352 if (Bcmp(netmask, x->rn_key, mlen) != 0) { 353 x = rn_addmask(netmask, 0, head->rn_off); 354 if (x == 0) 355 return (0); 356 } 357 netmask = x->rn_key; 358 b = -1 - x->rn_b; 359 } 360 /* 361 * Deal with duplicated keys: attach node to previous instance 362 */ 363 saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes); 364 if (keyduplicated) { 365 do { 366 if (tt->rn_mask == netmask) 367 return (0); 368 t = tt; 369 if (netmask == 0 || 370 (tt->rn_mask && rn_refines(netmask, tt->rn_mask))) 371 break; 372 } while (tt = tt->rn_dupedkey); 373 /* 374 * If the mask is not duplicated, we wouldn't 375 * find it among possible duplicate key entries 376 * anyway, so the above test doesn't hurt. 377 * 378 * We sort the masks 379 * for a duplicated key the same way as in a masklist. 380 * It is an unfortunate pain having to relocate 381 * the head of the list. 382 */ 383 if (tt && t == saved_tt) { 384 struct radix_node *xx = x; 385 /* link in at head of list */ 386 (tt = treenodes)->rn_dupedkey = t; 387 tt->rn_flags = t->rn_flags; 388 tt->rn_p = x = t->rn_p; 389 if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt; 390 saved_tt = tt; x = xx; 391 } else { 392 (tt = treenodes)->rn_dupedkey = t->rn_dupedkey; 393 t->rn_dupedkey = tt; 394 } 395 #ifdef RN_DEBUG 396 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; 397 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; 398 #endif 399 t = saved_tt; 400 tt->rn_key = (caddr_t) v; 401 tt->rn_b = -1; 402 tt->rn_flags = t->rn_flags & ~RNF_ROOT; 403 } 404 /* 405 * Put mask in tree. 406 */ 407 if (netmask) { 408 tt->rn_mask = netmask; 409 tt->rn_b = x->rn_b; 410 } 411 t = saved_tt->rn_p; 412 b_leaf = -1 - t->rn_b; 413 if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r; 414 /* Promote general routes from below */ 415 if (x->rn_b < 0) { 416 if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) { 417 MKGet(m); 418 if (m) { 419 Bzero(m, sizeof *m); 420 m->rm_b = x->rn_b; 421 m->rm_mask = x->rn_mask; 422 x->rn_mklist = t->rn_mklist = m; 423 } 424 } 425 } else if (x->rn_mklist) { 426 /* 427 * Skip over masks whose index is > that of new node 428 */ 429 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) 430 if (m->rm_b >= b_leaf) 431 break; 432 t->rn_mklist = m; *mp = 0; 433 } 434 /* Add new route to highest possible ancestor's list */ 435 if ((netmask == 0) || (b > t->rn_b )) 436 return tt; /* can't lift at all */ 437 b_leaf = tt->rn_b; 438 do { 439 x = t; 440 t = t->rn_p; 441 } while (b <= t->rn_b && x != head); 442 /* 443 * Search through routes associated with node to 444 * insert new route according to index. 445 * For nodes of equal index, place more specific 446 * masks first. 447 */ 448 cplim = netmask + mlen; 449 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) { 450 if (m->rm_b < b_leaf) 451 continue; 452 if (m->rm_b > b_leaf) 453 break; 454 if (m->rm_mask == netmask) { 455 m->rm_refs++; 456 tt->rn_mklist = m; 457 return tt; 458 } 459 if (rn_refines(netmask, m->rm_mask)) 460 break; 461 } 462 MKGet(m); 463 if (m == 0) { 464 printf("Mask for route not entered\n"); 465 return (tt); 466 } 467 Bzero(m, sizeof *m); 468 m->rm_b = b_leaf; 469 m->rm_mask = netmask; 470 m->rm_mklist = *mp; 471 *mp = m; 472 tt->rn_mklist = m; 473 return tt; 474 } 475 476 struct radix_node * 477 rn_delete(v, netmask, head) 478 caddr_t v, netmask; 479 struct radix_node *head; 480 { 481 register struct radix_node *t, *p, *x = head; 482 register struct radix_node *tt = rn_search(v, x); 483 int b, head_off = x->rn_off, vlen = * (u_char *) v; 484 struct radix_mask *m, *saved_m, **mp; 485 struct radix_node *dupedkey, *saved_tt = tt; 486 487 if (tt == 0 || 488 Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off)) 489 return (0); 490 /* 491 * Delete our route from mask lists. 492 */ 493 if (dupedkey = tt->rn_dupedkey) { 494 if (netmask) 495 netmask = rn_search(netmask, rn_maskhead)->rn_key; 496 while (tt->rn_mask != netmask) 497 if ((tt = tt->rn_dupedkey) == 0) 498 return (0); 499 } 500 if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0) 501 goto on1; 502 if (m->rm_mask != tt->rn_mask) { 503 printf("rn_delete: inconsistent annotation\n"); 504 goto on1; 505 } 506 if (--m->rm_refs >= 0) 507 goto on1; 508 b = -1 - tt->rn_b; 509 t = saved_tt->rn_p; 510 if (b > t->rn_b) 511 goto on1; /* Wasn't lifted at all */ 512 do { 513 x = t; 514 t = t->rn_p; 515 } while (b <= t->rn_b && x != head); 516 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) 517 if (m == saved_m) { 518 *mp = m->rm_mklist; 519 MKFree(m); 520 break; 521 } 522 if (m == 0) 523 printf("rn_delete: couldn't find our annotation\n"); 524 on1: 525 /* 526 * Eliminate us from tree 527 */ 528 if (tt->rn_flags & RNF_ROOT) 529 return (0); 530 #ifdef RN_DEBUG 531 /* Get us out of the creation list */ 532 for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {} 533 if (t) t->rn_ybro = tt->rn_ybro; 534 #endif RN_DEBUG 535 t = tt->rn_p; 536 if (dupedkey) { 537 if (tt == saved_tt) { 538 x = dupedkey; x->rn_p = t; 539 if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x; 540 } else { 541 for (x = p = saved_tt; p && p->rn_dupedkey != tt;) 542 p = p->rn_dupedkey; 543 if (p) p->rn_dupedkey = tt->rn_dupedkey; 544 else printf("rn_delete: couldn't find us\n"); 545 } 546 t = tt + 1; 547 if (t->rn_flags & RNF_ACTIVE) { 548 #ifndef RN_DEBUG 549 *++x = *t; p = t->rn_p; 550 #else 551 b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p; 552 #endif 553 if (p->rn_l == t) p->rn_l = x; else p->rn_r = x; 554 x->rn_l->rn_p = x; x->rn_r->rn_p = x; 555 } 556 goto out; 557 } 558 if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l; 559 p = t->rn_p; 560 if (p->rn_r == t) p->rn_r = x; else p->rn_l = x; 561 x->rn_p = p; 562 /* 563 * Demote routes attached to us. 564 */ 565 if (t->rn_mklist) { 566 if (x->rn_b >= 0) { 567 for (mp = &x->rn_mklist; m = *mp;) 568 mp = &m->rm_mklist; 569 *mp = t->rn_mklist; 570 } else { 571 for (m = t->rn_mklist; m;) { 572 struct radix_mask *mm = m->rm_mklist; 573 if (m == x->rn_mklist && (--(m->rm_refs) < 0)) { 574 x->rn_mklist = 0; 575 MKFree(m); 576 } else 577 printf("%s %x at %x\n", 578 "rn_delete: Orphaned Mask", m, x); 579 m = mm; 580 } 581 } 582 } 583 /* 584 * We may be holding an active internal node in the tree. 585 */ 586 x = tt + 1; 587 if (t != x) { 588 #ifndef RN_DEBUG 589 *t = *x; 590 #else 591 b = t->rn_info; *t = *x; t->rn_info = b; 592 #endif 593 t->rn_l->rn_p = t; t->rn_r->rn_p = t; 594 p = x->rn_p; 595 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t; 596 } 597 out: 598 tt->rn_flags &= ~RNF_ACTIVE; 599 tt[1].rn_flags &= ~RNF_ACTIVE; 600 return (tt); 601 } 602 603 rn_walk(rn, f, w) 604 register struct radix_node *rn; 605 register int (*f)(); 606 caddr_t w; 607 { 608 int error; 609 struct radix_node *orn; 610 for (;;) { 611 while (rn->rn_b >= 0) 612 rn = rn->rn_l; /* First time through node, go left */ 613 for (orn = rn; rn; rn = rn->rn_dupedkey) /* Process Leaves */ 614 if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w))) 615 return (error); 616 for (rn = orn; rn->rn_p->rn_r == rn; ) { /* If at right child */ 617 rn = rn->rn_p; /* go back up */ 618 if (rn->rn_flags & RNF_ROOT) 619 return 0; 620 } 621 rn = rn->rn_p->rn_r; /* otherwhise, go right*/ 622 } 623 } 624 char rn_zeros[MAXKEYLEN], rn_ones[MAXKEYLEN]; 625 626 rn_inithead(head, off) 627 struct radix_node_head **head; 628 int off; 629 { 630 register struct radix_node_head *rnh; 631 register struct radix_node *t, *tt, *ttt; 632 if (*head) 633 return (1); 634 R_Malloc(rnh, struct radix_node_head *, sizeof (*rnh)); 635 if (rnh == 0) 636 return (0); 637 Bzero(rnh, sizeof (*rnh)); 638 *head = rnh; 639 t = rn_newpair(rn_zeros, off, rnh->rnh_nodes); 640 ttt = rnh->rnh_nodes + 2; 641 t->rn_r = ttt; 642 t->rn_p = t; 643 tt = t->rn_l; 644 tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE; 645 tt->rn_b = -1 - off; 646 *ttt = *tt; 647 ttt->rn_key = rn_ones; 648 rnh->rnh_add = rn_addroute; 649 rnh->rnh_delete = rn_delete; 650 rnh->rnh_match = rn_match; 651 rnh->rnh_walk = rn_walk; 652 rnh->rnh_treetop = t; 653 if (mask_rnhead == 0) { 654 caddr_t cp = rn_ones, cplim = rn_ones + MAXKEYLEN; 655 while (cp < cplim) 656 *cp++ = -1; 657 if (rn_inithead(&mask_rnhead, 0) == 0) { 658 Free(rnh); 659 *head = 0; 660 return (0); 661 } 662 } 663 return (1); 664 } 665