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 7.17 (Berkeley) 10/11/92 8 */ 9 10 /* 11 * Routines to build and maintain radix trees for routing lookups. 12 */ 13 #ifndef RNF_NORMAL 14 #include <sys/param.h> 15 #include <sys/systm.h> 16 #include <sys/malloc.h> 17 #define M_DONTWAIT M_NOWAIT 18 #ifdef KERNEL 19 #include <sys/domain.h> 20 #endif 21 #endif 22 23 #include <net/radix.h> 24 25 int max_keylen; 26 struct radix_mask *rn_mkfreelist; 27 struct radix_node_head *mask_rnhead; 28 static int gotOddMasks; 29 static char *maskedKey; 30 static char *rn_zeros, *rn_ones; 31 32 #define rn_maskhead (mask_rnhead->rnh_treetop) 33 #undef Bcmp 34 #define Bcmp(a, b, l) (l == 0 ? 0 : bcmp((caddr_t)(a), (caddr_t)(b), (u_long)l)) 35 /* 36 * The data structure for the keys is a radix tree with one way 37 * branching removed. The index rn_b at an internal node n represents a bit 38 * position to be tested. The tree is arranged so that all descendants 39 * of a node n have keys whose bits all agree up to position rn_b - 1. 40 * (We say the index of n is rn_b.) 41 * 42 * There is at least one descendant which has a one bit at position rn_b, 43 * and at least one with a zero there. 44 * 45 * A route is determined by a pair of key and mask. We require that the 46 * bit-wise logical and of the key and mask to be the key. 47 * We define the index of a route to associated with the mask to be 48 * the first bit number in the mask where 0 occurs (with bit number 0 49 * representing the highest order bit). 50 * 51 * We say a mask is normal if every bit is 0, past the index of the mask. 52 * If a node n has a descendant (k, m) with index(m) == index(n) == rn_b, 53 * and m is a normal mask, then the route applies to every descendant of n. 54 * If the index(m) < rn_b, this implies the trailing last few bits of k 55 * before bit b are all 0, (and hence consequently true of every descendant 56 * of n), so the route applies to all descendants of the node as well. 57 * 58 * The present version of the code makes no use of normal routes, 59 * but similar logic shows that a non-normal mask m such that 60 * index(m) <= index(n) could potentially apply to many children of n. 61 * Thus, for each non-host route, we attach its mask to a list at an internal 62 * node as high in the tree as we can go. 63 */ 64 65 struct radix_node * 66 rn_search(v, head) 67 struct radix_node *head; 68 register caddr_t v; 69 { 70 register struct radix_node *x; 71 72 for (x = head; x->rn_b >= 0;) { 73 if (x->rn_bmask & v[x->rn_off]) 74 x = x->rn_r; 75 else 76 x = x->rn_l; 77 } 78 return x; 79 }; 80 81 struct radix_node * 82 rn_search_m(v, head, m) 83 struct radix_node *head; 84 register caddr_t v, m; 85 { 86 register struct radix_node *x; 87 88 for (x = head; x->rn_b >= 0;) { 89 if ((x->rn_bmask & m[x->rn_off]) && 90 (x->rn_bmask & v[x->rn_off])) 91 x = x->rn_r; 92 else 93 x = x->rn_l; 94 } 95 return x; 96 }; 97 98 rn_refines(m, n) 99 register caddr_t m, n; 100 { 101 register caddr_t lim, lim2 = lim = n + *(u_char *)n; 102 int longer = (*(u_char *)n++) - (int)(*(u_char *)m++); 103 int masks_are_equal = 1; 104 105 if (longer > 0) 106 lim -= longer; 107 while (n < lim) { 108 if (*n & ~(*m)) 109 return 0; 110 if (*n++ != *m++) 111 masks_are_equal = 0; 112 113 } 114 while (n < lim2) 115 if (*n++) 116 return 0; 117 if (masks_are_equal && (longer < 0)) 118 for (lim2 = m - longer; m < lim2; ) 119 if (*m++) 120 return 1; 121 return (!masks_are_equal); 122 } 123 124 125 struct radix_node * 126 rn_match(v, head) 127 struct radix_node *head; 128 caddr_t v; 129 { 130 register struct radix_node *t = head, *x; 131 register caddr_t cp = v, cp2, cp3; 132 caddr_t cplim, mstart; 133 struct radix_node *saved_t; 134 int off = t->rn_off, vlen = *(u_char *)cp, matched_off; 135 136 /* 137 * Open code rn_search(v, head) to avoid overhead of extra 138 * subroutine call. 139 */ 140 for (; t->rn_b >= 0; ) { 141 if (t->rn_bmask & cp[t->rn_off]) 142 t = t->rn_r; 143 else 144 t = t->rn_l; 145 } 146 /* 147 * See if we match exactly as a host destination 148 */ 149 cp += off; cp2 = t->rn_key + off; cplim = v + vlen; 150 for (; cp < cplim; cp++, cp2++) 151 if (*cp != *cp2) 152 goto on1; 153 /* 154 * This extra grot is in case we are explicitly asked 155 * to look up the default. Ugh! 156 */ 157 if ((t->rn_flags & RNF_ROOT) && t->rn_dupedkey) 158 t = t->rn_dupedkey; 159 return t; 160 on1: 161 matched_off = cp - v; 162 saved_t = t; 163 do { 164 if (t->rn_mask) { 165 /* 166 * Even if we don't match exactly as a hosts; 167 * we may match if the leaf we wound up at is 168 * a route to a net. 169 */ 170 cp3 = matched_off + t->rn_mask; 171 cp2 = matched_off + t->rn_key; 172 for (; cp < cplim; cp++) 173 if ((*cp2++ ^ *cp) & *cp3++) 174 break; 175 if (cp == cplim) 176 return t; 177 cp = matched_off + v; 178 } 179 } while (t = t->rn_dupedkey); 180 t = saved_t; 181 /* start searching up the tree */ 182 do { 183 register struct radix_mask *m; 184 t = t->rn_p; 185 if (m = t->rn_mklist) { 186 /* 187 * After doing measurements here, it may 188 * turn out to be faster to open code 189 * rn_search_m here instead of always 190 * copying and masking. 191 */ 192 off = min(t->rn_off, matched_off); 193 mstart = maskedKey + off; 194 do { 195 cp2 = mstart; 196 cp3 = m->rm_mask + off; 197 for (cp = v + off; cp < cplim;) 198 *cp2++ = *cp++ & *cp3++; 199 x = rn_search(maskedKey, t); 200 while (x && x->rn_mask != m->rm_mask) 201 x = x->rn_dupedkey; 202 if (x && 203 (Bcmp(mstart, x->rn_key + off, 204 vlen - off) == 0)) 205 return x; 206 } while (m = m->rm_mklist); 207 } 208 } while (t != head); 209 return 0; 210 }; 211 212 #ifdef RN_DEBUG 213 int rn_nodenum; 214 struct radix_node *rn_clist; 215 int rn_saveinfo; 216 #endif 217 218 struct radix_node * 219 rn_newpair(v, b, nodes) 220 caddr_t v; 221 int b; 222 struct radix_node nodes[2]; 223 { 224 register struct radix_node *tt = nodes, *t = tt + 1; 225 t->rn_b = b; t->rn_bmask = 0x80 >> (b & 7); 226 t->rn_l = tt; t->rn_off = b >> 3; 227 tt->rn_b = -1; tt->rn_key = v; tt->rn_p = t; 228 tt->rn_flags = t->rn_flags = RNF_ACTIVE; 229 #ifdef RN_DEBUG 230 tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; 231 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; 232 #endif 233 return t; 234 } 235 236 int rn_debug = 1; 237 struct radix_node * 238 rn_insert(v, head, dupentry, nodes) 239 caddr_t v; 240 struct radix_node *head; 241 int *dupentry; 242 struct radix_node nodes[2]; 243 { 244 int head_off = head->rn_off, vlen = (int)*((u_char *)v); 245 register struct radix_node *t = rn_search(v, head); 246 register caddr_t cp = v + head_off; 247 register int b; 248 struct radix_node *tt; 249 /* 250 *find first bit at which v and t->rn_key differ 251 */ 252 { 253 register caddr_t cp2 = t->rn_key + head_off; 254 register int cmp_res; 255 caddr_t cplim = v + vlen; 256 257 while (cp < cplim) 258 if (*cp2++ != *cp++) 259 goto on1; 260 *dupentry = 1; 261 return t; 262 on1: 263 *dupentry = 0; 264 cmp_res = (cp[-1] ^ cp2[-1]) & 0xff; 265 for (b = (cp - v) << 3; cmp_res; b--) 266 cmp_res >>= 1; 267 } 268 { 269 register struct radix_node *p, *x = head; 270 cp = v; 271 do { 272 p = x; 273 if (cp[x->rn_off] & x->rn_bmask) 274 x = x->rn_r; 275 else x = x->rn_l; 276 } while (b > (unsigned) x->rn_b); /* x->rn_b < b && x->rn_b >= 0 */ 277 #ifdef RN_DEBUG 278 if (rn_debug) 279 printf("Going In:\n"), traverse(p); 280 #endif 281 t = rn_newpair(v, b, nodes); tt = t->rn_l; 282 if ((cp[p->rn_off] & p->rn_bmask) == 0) 283 p->rn_l = t; 284 else 285 p->rn_r = t; 286 x->rn_p = t; t->rn_p = p; /* frees x, p as temp vars below */ 287 if ((cp[t->rn_off] & t->rn_bmask) == 0) { 288 t->rn_r = x; 289 } else { 290 t->rn_r = tt; t->rn_l = x; 291 } 292 #ifdef RN_DEBUG 293 if (rn_debug) 294 printf("Coming out:\n"), traverse(p); 295 #endif 296 } 297 return (tt); 298 } 299 300 struct radix_node * 301 rn_addmask(netmask, search, skip) 302 caddr_t netmask; 303 int search, skip; 304 { 305 register struct radix_node *x; 306 register caddr_t cp, cplim; 307 register int b, mlen, j; 308 int maskduplicated; 309 310 mlen = *(u_char *)netmask; 311 if (search) { 312 x = rn_search(netmask, rn_maskhead); 313 mlen = *(u_char *)netmask; 314 if (Bcmp(netmask, x->rn_key, mlen) == 0) 315 return (x); 316 } 317 R_Malloc(x, struct radix_node *, max_keylen + 2 * sizeof (*x)); 318 if (x == 0) 319 return (0); 320 Bzero(x, max_keylen + 2 * sizeof (*x)); 321 cp = (caddr_t)(x + 2); 322 Bcopy(netmask, cp, mlen); 323 netmask = cp; 324 x = rn_insert(netmask, rn_maskhead, &maskduplicated, x); 325 /* 326 * Calculate index of mask. 327 */ 328 cplim = netmask + mlen; 329 for (cp = netmask + skip; cp < cplim; cp++) 330 if (*(u_char *)cp != 0xff) 331 break; 332 b = (cp - netmask) << 3; 333 if (cp != cplim) { 334 if (*cp != 0) { 335 gotOddMasks = 1; 336 for (j = 0x80; j; b++, j >>= 1) 337 if ((j & *cp) == 0) 338 break; 339 } 340 } 341 x->rn_b = -1 - b; 342 return (x); 343 } 344 345 struct radix_node * 346 rn_addroute(v, netmask, head, treenodes) 347 caddr_t v, netmask; 348 struct radix_node *head; 349 struct radix_node treenodes[2]; 350 { 351 register int j; 352 register caddr_t cp; 353 register struct radix_node *t, *x, *tt; 354 short b = 0, b_leaf; 355 int vlen = *(u_char *)v, mlen, keyduplicated; 356 caddr_t cplim; unsigned char *maskp; 357 struct radix_mask *m, **mp; 358 struct radix_node *saved_tt; 359 360 /* 361 * In dealing with non-contiguous masks, there may be 362 * many different routes which have the same mask. 363 * We will find it useful to have a unique pointer to 364 * the mask to speed avoiding duplicate references at 365 * nodes and possibly save time in calculating indices. 366 */ 367 if (netmask) { 368 x = rn_search(netmask, rn_maskhead); 369 mlen = *(u_char *)netmask; 370 if (Bcmp(netmask, x->rn_key, mlen) != 0) { 371 x = rn_addmask(netmask, 0, head->rn_off); 372 if (x == 0) 373 return (0); 374 } 375 netmask = x->rn_key; 376 b = -1 - x->rn_b; 377 } 378 /* 379 * Deal with duplicated keys: attach node to previous instance 380 */ 381 saved_tt = tt = rn_insert(v, head, &keyduplicated, treenodes); 382 if (keyduplicated) { 383 do { 384 if (tt->rn_mask == netmask) 385 return (0); 386 t = tt; 387 if (netmask == 0 || 388 (tt->rn_mask && rn_refines(netmask, tt->rn_mask))) 389 break; 390 } while (tt = tt->rn_dupedkey); 391 /* 392 * If the mask is not duplicated, we wouldn't 393 * find it among possible duplicate key entries 394 * anyway, so the above test doesn't hurt. 395 * 396 * We sort the masks for a duplicated key the same way as 397 * in a masklist -- most specific to least specific. 398 * This may require the unfortunate nuisance of relocating 399 * the head of the list. 400 */ 401 if (tt && t == saved_tt) { 402 struct radix_node *xx = x; 403 /* link in at head of list */ 404 (tt = treenodes)->rn_dupedkey = t; 405 tt->rn_flags = t->rn_flags; 406 tt->rn_p = x = t->rn_p; 407 if (x->rn_l == t) x->rn_l = tt; else x->rn_r = tt; 408 saved_tt = tt; x = xx; 409 } else { 410 (tt = treenodes)->rn_dupedkey = t->rn_dupedkey; 411 t->rn_dupedkey = tt; 412 } 413 #ifdef RN_DEBUG 414 t=tt+1; tt->rn_info = rn_nodenum++; t->rn_info = rn_nodenum++; 415 tt->rn_twin = t; tt->rn_ybro = rn_clist; rn_clist = tt; 416 #endif 417 t = saved_tt; 418 tt->rn_key = (caddr_t) v; 419 tt->rn_b = -1; 420 tt->rn_flags = t->rn_flags & ~RNF_ROOT; 421 } 422 /* 423 * Put mask in tree. 424 */ 425 if (netmask) { 426 tt->rn_mask = netmask; 427 tt->rn_b = x->rn_b; 428 } 429 t = saved_tt->rn_p; 430 b_leaf = -1 - t->rn_b; 431 if (t->rn_r == saved_tt) x = t->rn_l; else x = t->rn_r; 432 /* Promote general routes from below */ 433 if (x->rn_b < 0) { 434 if (x->rn_mask && (x->rn_b >= b_leaf) && x->rn_mklist == 0) { 435 MKGet(m); 436 if (m) { 437 Bzero(m, sizeof *m); 438 m->rm_b = x->rn_b; 439 m->rm_mask = x->rn_mask; 440 x->rn_mklist = t->rn_mklist = m; 441 } 442 } 443 } else if (x->rn_mklist) { 444 /* 445 * Skip over masks whose index is > that of new node 446 */ 447 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) 448 if (m->rm_b >= b_leaf) 449 break; 450 t->rn_mklist = m; *mp = 0; 451 } 452 /* Add new route to highest possible ancestor's list */ 453 if ((netmask == 0) || (b > t->rn_b )) 454 return tt; /* can't lift at all */ 455 b_leaf = tt->rn_b; 456 do { 457 x = t; 458 t = t->rn_p; 459 } while (b <= t->rn_b && x != head); 460 /* 461 * Search through routes associated with node to 462 * insert new route according to index. 463 * For nodes of equal index, place more specific 464 * masks first. 465 */ 466 cplim = netmask + mlen; 467 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) { 468 if (m->rm_b < b_leaf) 469 continue; 470 if (m->rm_b > b_leaf) 471 break; 472 if (m->rm_mask == netmask) { 473 m->rm_refs++; 474 tt->rn_mklist = m; 475 return tt; 476 } 477 if (rn_refines(netmask, m->rm_mask)) 478 break; 479 } 480 MKGet(m); 481 if (m == 0) { 482 printf("Mask for route not entered\n"); 483 return (tt); 484 } 485 Bzero(m, sizeof *m); 486 m->rm_b = b_leaf; 487 m->rm_mask = netmask; 488 m->rm_mklist = *mp; 489 *mp = m; 490 tt->rn_mklist = m; 491 return tt; 492 } 493 494 struct radix_node * 495 rn_delete(v, netmask, head) 496 caddr_t v, netmask; 497 struct radix_node *head; 498 { 499 register struct radix_node *t, *p, *x = head; 500 register struct radix_node *tt = rn_search(v, x); 501 int b, head_off = x->rn_off, vlen = * (u_char *) v; 502 struct radix_mask *m, *saved_m, **mp; 503 struct radix_node *dupedkey, *saved_tt = tt; 504 505 if (tt == 0 || 506 Bcmp(v + head_off, tt->rn_key + head_off, vlen - head_off)) 507 return (0); 508 /* 509 * Delete our route from mask lists. 510 */ 511 if (dupedkey = tt->rn_dupedkey) { 512 if (netmask) 513 netmask = rn_search(netmask, rn_maskhead)->rn_key; 514 while (tt->rn_mask != netmask) 515 if ((tt = tt->rn_dupedkey) == 0) 516 return (0); 517 } 518 if (tt->rn_mask == 0 || (saved_m = m = tt->rn_mklist) == 0) 519 goto on1; 520 if (m->rm_mask != tt->rn_mask) { 521 printf("rn_delete: inconsistent annotation\n"); 522 goto on1; 523 } 524 if (--m->rm_refs >= 0) 525 goto on1; 526 b = -1 - tt->rn_b; 527 t = saved_tt->rn_p; 528 if (b > t->rn_b) 529 goto on1; /* Wasn't lifted at all */ 530 do { 531 x = t; 532 t = t->rn_p; 533 } while (b <= t->rn_b && x != head); 534 for (mp = &x->rn_mklist; m = *mp; mp = &m->rm_mklist) 535 if (m == saved_m) { 536 *mp = m->rm_mklist; 537 MKFree(m); 538 break; 539 } 540 if (m == 0) 541 printf("rn_delete: couldn't find our annotation\n"); 542 on1: 543 /* 544 * Eliminate us from tree 545 */ 546 if (tt->rn_flags & RNF_ROOT) 547 return (0); 548 #ifdef RN_DEBUG 549 /* Get us out of the creation list */ 550 for (t = rn_clist; t && t->rn_ybro != tt; t = t->rn_ybro) {} 551 if (t) t->rn_ybro = tt->rn_ybro; 552 #endif RN_DEBUG 553 t = tt->rn_p; 554 if (dupedkey) { 555 if (tt == saved_tt) { 556 x = dupedkey; x->rn_p = t; 557 if (t->rn_l == tt) t->rn_l = x; else t->rn_r = x; 558 } else { 559 for (x = p = saved_tt; p && p->rn_dupedkey != tt;) 560 p = p->rn_dupedkey; 561 if (p) p->rn_dupedkey = tt->rn_dupedkey; 562 else printf("rn_delete: couldn't find us\n"); 563 } 564 t = tt + 1; 565 if (t->rn_flags & RNF_ACTIVE) { 566 #ifndef RN_DEBUG 567 *++x = *t; p = t->rn_p; 568 #else 569 b = t->rn_info; *++x = *t; t->rn_info = b; p = t->rn_p; 570 #endif 571 if (p->rn_l == t) p->rn_l = x; else p->rn_r = x; 572 x->rn_l->rn_p = x; x->rn_r->rn_p = x; 573 } 574 goto out; 575 } 576 if (t->rn_l == tt) x = t->rn_r; else x = t->rn_l; 577 p = t->rn_p; 578 if (p->rn_r == t) p->rn_r = x; else p->rn_l = x; 579 x->rn_p = p; 580 /* 581 * Demote routes attached to us. 582 */ 583 if (t->rn_mklist) { 584 if (x->rn_b >= 0) { 585 for (mp = &x->rn_mklist; m = *mp;) 586 mp = &m->rm_mklist; 587 *mp = t->rn_mklist; 588 } else { 589 for (m = t->rn_mklist; m;) { 590 struct radix_mask *mm = m->rm_mklist; 591 if (m == x->rn_mklist && (--(m->rm_refs) < 0)) { 592 x->rn_mklist = 0; 593 MKFree(m); 594 } else 595 printf("%s %x at %x\n", 596 "rn_delete: Orphaned Mask", m, x); 597 m = mm; 598 } 599 } 600 } 601 /* 602 * We may be holding an active internal node in the tree. 603 */ 604 x = tt + 1; 605 if (t != x) { 606 #ifndef RN_DEBUG 607 *t = *x; 608 #else 609 b = t->rn_info; *t = *x; t->rn_info = b; 610 #endif 611 t->rn_l->rn_p = t; t->rn_r->rn_p = t; 612 p = x->rn_p; 613 if (p->rn_l == x) p->rn_l = t; else p->rn_r = t; 614 } 615 out: 616 tt->rn_flags &= ~RNF_ACTIVE; 617 tt[1].rn_flags &= ~RNF_ACTIVE; 618 return (tt); 619 } 620 621 rn_walk(rn, f, w) 622 register struct radix_node *rn; 623 register int (*f)(); 624 caddr_t w; 625 { 626 int error; 627 struct radix_node *base, *next; 628 /* 629 * This gets complicated because we may delete the node 630 * while applying the function f to it, so we need to calculate 631 * the successor node in advance. 632 */ 633 /* First time through node, go left */ 634 while (rn->rn_b >= 0) 635 rn = rn->rn_l; 636 for (;;) { 637 base = rn; 638 /* If at right child go back up, otherwise, go right */ 639 while (rn->rn_p->rn_r == rn && (rn->rn_flags & RNF_ROOT) == 0) 640 rn = rn->rn_p; 641 /* Find the next *leaf* since next node might vanish, too */ 642 for (rn = rn->rn_p->rn_r; rn->rn_b >= 0;) 643 rn = rn->rn_l; 644 next = rn; 645 /* Process leaves */ 646 while (rn = base) { 647 base = rn->rn_dupedkey; 648 if (!(rn->rn_flags & RNF_ROOT) && (error = (*f)(rn, w))) 649 return (error); 650 } 651 rn = next; 652 if (rn->rn_flags & RNF_ROOT) 653 return (0); 654 } 655 } 656 657 rn_inithead(head, off) 658 void **head; 659 int off; 660 { 661 register struct radix_node_head *rnh; 662 register struct radix_node *t, *tt, *ttt; 663 if (*head) 664 return (1); 665 R_Malloc(rnh, struct radix_node_head *, sizeof (*rnh)); 666 if (rnh == 0) 667 return (0); 668 Bzero(rnh, sizeof (*rnh)); 669 *head = rnh; 670 t = rn_newpair(rn_zeros, off, rnh->rnh_nodes); 671 ttt = rnh->rnh_nodes + 2; 672 t->rn_r = ttt; 673 t->rn_p = t; 674 tt = t->rn_l; 675 tt->rn_flags = t->rn_flags = RNF_ROOT | RNF_ACTIVE; 676 tt->rn_b = -1 - off; 677 *ttt = *tt; 678 ttt->rn_key = rn_ones; 679 rnh->rnh_add = rn_addroute; 680 rnh->rnh_delete = rn_delete; 681 rnh->rnh_match = rn_match; 682 rnh->rnh_walk = rn_walk; 683 rnh->rnh_treetop = t; 684 return (1); 685 } 686 687 rn_init() 688 { 689 char *cp, *cplim; 690 #ifdef KERNEL 691 struct domain *dom; 692 693 for (dom = domains; dom; dom = dom->dom_next) 694 if (dom->dom_maxrtkey > max_keylen) 695 max_keylen = dom->dom_maxrtkey; 696 #endif 697 if (max_keylen == 0) { 698 printf("rn_init: radix functions require max_keylen be set\n"); 699 return; 700 } 701 R_Malloc(rn_zeros, char *, 3 * max_keylen); 702 if (rn_zeros == NULL) 703 panic("rn_init"); 704 Bzero(rn_zeros, 3 * max_keylen); 705 rn_ones = cp = rn_zeros + max_keylen; 706 maskedKey = cplim = rn_ones + max_keylen; 707 while (cp < cplim) 708 *cp++ = -1; 709 if (rn_inithead((void **)&mask_rnhead, 0) == 0) 710 panic("rn_init 2"); 711 } 712