1 /* 2 * Linux INET6 implementation 3 * Forwarding Information Database 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * 8 * $Id: ip6_fib.c,v 1.25 2001/10/31 21:55:55 davem Exp $ 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 /* 17 * Changes: 18 * Yuji SEKIYA @USAGI: Support default route on router node; 19 * remove ip6_null_entry from the top of 20 * routing table. 21 */ 22 #include <linux/config.h> 23 #include <linux/errno.h> 24 #include <linux/types.h> 25 #include <linux/net.h> 26 #include <linux/route.h> 27 #include <linux/netdevice.h> 28 #include <linux/in6.h> 29 #include <linux/init.h> 30 31 #ifdef CONFIG_PROC_FS 32 #include <linux/proc_fs.h> 33 #endif 34 35 #include <net/ipv6.h> 36 #include <net/ndisc.h> 37 #include <net/addrconf.h> 38 39 #include <net/ip6_fib.h> 40 #include <net/ip6_route.h> 41 42 #define RT6_DEBUG 2 43 44 #if RT6_DEBUG >= 3 45 #define RT6_TRACE(x...) printk(KERN_DEBUG x) 46 #else 47 #define RT6_TRACE(x...) do { ; } while (0) 48 #endif 49 50 struct rt6_statistics rt6_stats; 51 52 static kmem_cache_t * fib6_node_kmem; 53 54 enum fib_walk_state_t 55 { 56 #ifdef CONFIG_IPV6_SUBTREES 57 FWS_S, 58 #endif 59 FWS_L, 60 FWS_R, 61 FWS_C, 62 FWS_U 63 }; 64 65 struct fib6_cleaner_t 66 { 67 struct fib6_walker_t w; 68 int (*func)(struct rt6_info *, void *arg); 69 void *arg; 70 }; 71 72 DEFINE_RWLOCK(fib6_walker_lock); 73 74 75 #ifdef CONFIG_IPV6_SUBTREES 76 #define FWS_INIT FWS_S 77 #define SUBTREE(fn) ((fn)->subtree) 78 #else 79 #define FWS_INIT FWS_L 80 #define SUBTREE(fn) NULL 81 #endif 82 83 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt); 84 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn); 85 86 /* 87 * A routing update causes an increase of the serial number on the 88 * affected subtree. This allows for cached routes to be asynchronously 89 * tested when modifications are made to the destination cache as a 90 * result of redirects, path MTU changes, etc. 91 */ 92 93 static __u32 rt_sernum; 94 95 static struct timer_list ip6_fib_timer = TIMER_INITIALIZER(fib6_run_gc, 0, 0); 96 97 struct fib6_walker_t fib6_walker_list = { 98 .prev = &fib6_walker_list, 99 .next = &fib6_walker_list, 100 }; 101 102 #define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next) 103 104 static __inline__ u32 fib6_new_sernum(void) 105 { 106 u32 n = ++rt_sernum; 107 if ((__s32)n <= 0) 108 rt_sernum = n = 1; 109 return n; 110 } 111 112 /* 113 * Auxiliary address test functions for the radix tree. 114 * 115 * These assume a 32bit processor (although it will work on 116 * 64bit processors) 117 */ 118 119 /* 120 * test bit 121 */ 122 123 static __inline__ int addr_bit_set(void *token, int fn_bit) 124 { 125 __u32 *addr = token; 126 127 return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5]; 128 } 129 130 /* 131 * find the first different bit between two addresses 132 * length of address must be a multiple of 32bits 133 */ 134 135 static __inline__ int addr_diff(void *token1, void *token2, int addrlen) 136 { 137 __u32 *a1 = token1; 138 __u32 *a2 = token2; 139 int i; 140 141 addrlen >>= 2; 142 143 for (i = 0; i < addrlen; i++) { 144 __u32 xb; 145 146 xb = a1[i] ^ a2[i]; 147 148 if (xb) { 149 int j = 31; 150 151 xb = ntohl(xb); 152 153 while ((xb & (1 << j)) == 0) 154 j--; 155 156 return (i * 32 + 31 - j); 157 } 158 } 159 160 /* 161 * we should *never* get to this point since that 162 * would mean the addrs are equal 163 * 164 * However, we do get to it 8) And exacly, when 165 * addresses are equal 8) 166 * 167 * ip route add 1111::/128 via ... 168 * ip route add 1111::/64 via ... 169 * and we are here. 170 * 171 * Ideally, this function should stop comparison 172 * at prefix length. It does not, but it is still OK, 173 * if returned value is greater than prefix length. 174 * --ANK (980803) 175 */ 176 177 return addrlen<<5; 178 } 179 180 static __inline__ struct fib6_node * node_alloc(void) 181 { 182 struct fib6_node *fn; 183 184 if ((fn = kmem_cache_alloc(fib6_node_kmem, SLAB_ATOMIC)) != NULL) 185 memset(fn, 0, sizeof(struct fib6_node)); 186 187 return fn; 188 } 189 190 static __inline__ void node_free(struct fib6_node * fn) 191 { 192 kmem_cache_free(fib6_node_kmem, fn); 193 } 194 195 static __inline__ void rt6_release(struct rt6_info *rt) 196 { 197 if (atomic_dec_and_test(&rt->rt6i_ref)) 198 dst_free(&rt->u.dst); 199 } 200 201 202 /* 203 * Routing Table 204 * 205 * return the appropriate node for a routing tree "add" operation 206 * by either creating and inserting or by returning an existing 207 * node. 208 */ 209 210 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, 211 int addrlen, int plen, 212 int offset) 213 { 214 struct fib6_node *fn, *in, *ln; 215 struct fib6_node *pn = NULL; 216 struct rt6key *key; 217 int bit; 218 int dir = 0; 219 __u32 sernum = fib6_new_sernum(); 220 221 RT6_TRACE("fib6_add_1\n"); 222 223 /* insert node in tree */ 224 225 fn = root; 226 227 do { 228 key = (struct rt6key *)((u8 *)fn->leaf + offset); 229 230 /* 231 * Prefix match 232 */ 233 if (plen < fn->fn_bit || 234 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) 235 goto insert_above; 236 237 /* 238 * Exact match ? 239 */ 240 241 if (plen == fn->fn_bit) { 242 /* clean up an intermediate node */ 243 if ((fn->fn_flags & RTN_RTINFO) == 0) { 244 rt6_release(fn->leaf); 245 fn->leaf = NULL; 246 } 247 248 fn->fn_sernum = sernum; 249 250 return fn; 251 } 252 253 /* 254 * We have more bits to go 255 */ 256 257 /* Try to walk down on tree. */ 258 fn->fn_sernum = sernum; 259 dir = addr_bit_set(addr, fn->fn_bit); 260 pn = fn; 261 fn = dir ? fn->right: fn->left; 262 } while (fn); 263 264 /* 265 * We walked to the bottom of tree. 266 * Create new leaf node without children. 267 */ 268 269 ln = node_alloc(); 270 271 if (ln == NULL) 272 return NULL; 273 ln->fn_bit = plen; 274 275 ln->parent = pn; 276 ln->fn_sernum = sernum; 277 278 if (dir) 279 pn->right = ln; 280 else 281 pn->left = ln; 282 283 return ln; 284 285 286 insert_above: 287 /* 288 * split since we don't have a common prefix anymore or 289 * we have a less significant route. 290 * we've to insert an intermediate node on the list 291 * this new node will point to the one we need to create 292 * and the current 293 */ 294 295 pn = fn->parent; 296 297 /* find 1st bit in difference between the 2 addrs. 298 299 See comment in addr_diff: bit may be an invalid value, 300 but if it is >= plen, the value is ignored in any case. 301 */ 302 303 bit = addr_diff(addr, &key->addr, addrlen); 304 305 /* 306 * (intermediate)[in] 307 * / \ 308 * (new leaf node)[ln] (old node)[fn] 309 */ 310 if (plen > bit) { 311 in = node_alloc(); 312 ln = node_alloc(); 313 314 if (in == NULL || ln == NULL) { 315 if (in) 316 node_free(in); 317 if (ln) 318 node_free(ln); 319 return NULL; 320 } 321 322 /* 323 * new intermediate node. 324 * RTN_RTINFO will 325 * be off since that an address that chooses one of 326 * the branches would not match less specific routes 327 * in the other branch 328 */ 329 330 in->fn_bit = bit; 331 332 in->parent = pn; 333 in->leaf = fn->leaf; 334 atomic_inc(&in->leaf->rt6i_ref); 335 336 in->fn_sernum = sernum; 337 338 /* update parent pointer */ 339 if (dir) 340 pn->right = in; 341 else 342 pn->left = in; 343 344 ln->fn_bit = plen; 345 346 ln->parent = in; 347 fn->parent = in; 348 349 ln->fn_sernum = sernum; 350 351 if (addr_bit_set(addr, bit)) { 352 in->right = ln; 353 in->left = fn; 354 } else { 355 in->left = ln; 356 in->right = fn; 357 } 358 } else { /* plen <= bit */ 359 360 /* 361 * (new leaf node)[ln] 362 * / \ 363 * (old node)[fn] NULL 364 */ 365 366 ln = node_alloc(); 367 368 if (ln == NULL) 369 return NULL; 370 371 ln->fn_bit = plen; 372 373 ln->parent = pn; 374 375 ln->fn_sernum = sernum; 376 377 if (dir) 378 pn->right = ln; 379 else 380 pn->left = ln; 381 382 if (addr_bit_set(&key->addr, plen)) 383 ln->right = fn; 384 else 385 ln->left = fn; 386 387 fn->parent = ln; 388 } 389 return ln; 390 } 391 392 /* 393 * Insert routing information in a node. 394 */ 395 396 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 397 struct nlmsghdr *nlh) 398 { 399 struct rt6_info *iter = NULL; 400 struct rt6_info **ins; 401 402 ins = &fn->leaf; 403 404 if (fn->fn_flags&RTN_TL_ROOT && 405 fn->leaf == &ip6_null_entry && 406 !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){ 407 fn->leaf = rt; 408 rt->u.next = NULL; 409 goto out; 410 } 411 412 for (iter = fn->leaf; iter; iter=iter->u.next) { 413 /* 414 * Search for duplicates 415 */ 416 417 if (iter->rt6i_metric == rt->rt6i_metric) { 418 /* 419 * Same priority level 420 */ 421 422 if (iter->rt6i_dev == rt->rt6i_dev && 423 iter->rt6i_idev == rt->rt6i_idev && 424 ipv6_addr_equal(&iter->rt6i_gateway, 425 &rt->rt6i_gateway)) { 426 if (!(iter->rt6i_flags&RTF_EXPIRES)) 427 return -EEXIST; 428 iter->rt6i_expires = rt->rt6i_expires; 429 if (!(rt->rt6i_flags&RTF_EXPIRES)) { 430 iter->rt6i_flags &= ~RTF_EXPIRES; 431 iter->rt6i_expires = 0; 432 } 433 return -EEXIST; 434 } 435 } 436 437 if (iter->rt6i_metric > rt->rt6i_metric) 438 break; 439 440 ins = &iter->u.next; 441 } 442 443 /* 444 * insert node 445 */ 446 447 out: 448 rt->u.next = iter; 449 *ins = rt; 450 rt->rt6i_node = fn; 451 atomic_inc(&rt->rt6i_ref); 452 inet6_rt_notify(RTM_NEWROUTE, rt, nlh); 453 rt6_stats.fib_rt_entries++; 454 455 if ((fn->fn_flags & RTN_RTINFO) == 0) { 456 rt6_stats.fib_route_nodes++; 457 fn->fn_flags |= RTN_RTINFO; 458 } 459 460 return 0; 461 } 462 463 static __inline__ void fib6_start_gc(struct rt6_info *rt) 464 { 465 if (ip6_fib_timer.expires == 0 && 466 (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE))) 467 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); 468 } 469 470 void fib6_force_start_gc(void) 471 { 472 if (ip6_fib_timer.expires == 0) 473 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); 474 } 475 476 /* 477 * Add routing information to the routing tree. 478 * <destination addr>/<source addr> 479 * with source addr info in sub-trees 480 */ 481 482 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr) 483 { 484 struct fib6_node *fn; 485 int err = -ENOMEM; 486 487 fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr), 488 rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst)); 489 490 if (fn == NULL) 491 goto out; 492 493 #ifdef CONFIG_IPV6_SUBTREES 494 if (rt->rt6i_src.plen) { 495 struct fib6_node *sn; 496 497 if (fn->subtree == NULL) { 498 struct fib6_node *sfn; 499 500 /* 501 * Create subtree. 502 * 503 * fn[main tree] 504 * | 505 * sfn[subtree root] 506 * \ 507 * sn[new leaf node] 508 */ 509 510 /* Create subtree root node */ 511 sfn = node_alloc(); 512 if (sfn == NULL) 513 goto st_failure; 514 515 sfn->leaf = &ip6_null_entry; 516 atomic_inc(&ip6_null_entry.rt6i_ref); 517 sfn->fn_flags = RTN_ROOT; 518 sfn->fn_sernum = fib6_new_sernum(); 519 520 /* Now add the first leaf node to new subtree */ 521 522 sn = fib6_add_1(sfn, &rt->rt6i_src.addr, 523 sizeof(struct in6_addr), rt->rt6i_src.plen, 524 offsetof(struct rt6_info, rt6i_src)); 525 526 if (sn == NULL) { 527 /* If it is failed, discard just allocated 528 root, and then (in st_failure) stale node 529 in main tree. 530 */ 531 node_free(sfn); 532 goto st_failure; 533 } 534 535 /* Now link new subtree to main tree */ 536 sfn->parent = fn; 537 fn->subtree = sfn; 538 if (fn->leaf == NULL) { 539 fn->leaf = rt; 540 atomic_inc(&rt->rt6i_ref); 541 } 542 } else { 543 sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr, 544 sizeof(struct in6_addr), rt->rt6i_src.plen, 545 offsetof(struct rt6_info, rt6i_src)); 546 547 if (sn == NULL) 548 goto st_failure; 549 } 550 551 fn = sn; 552 } 553 #endif 554 555 err = fib6_add_rt2node(fn, rt, nlh); 556 557 if (err == 0) { 558 fib6_start_gc(rt); 559 if (!(rt->rt6i_flags&RTF_CACHE)) 560 fib6_prune_clones(fn, rt); 561 } 562 563 out: 564 if (err) 565 dst_free(&rt->u.dst); 566 return err; 567 568 #ifdef CONFIG_IPV6_SUBTREES 569 /* Subtree creation failed, probably main tree node 570 is orphan. If it is, shoot it. 571 */ 572 st_failure: 573 if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT))) 574 fib6_repair_tree(fn); 575 dst_free(&rt->u.dst); 576 return err; 577 #endif 578 } 579 580 /* 581 * Routing tree lookup 582 * 583 */ 584 585 struct lookup_args { 586 int offset; /* key offset on rt6_info */ 587 struct in6_addr *addr; /* search key */ 588 }; 589 590 static struct fib6_node * fib6_lookup_1(struct fib6_node *root, 591 struct lookup_args *args) 592 { 593 struct fib6_node *fn; 594 int dir; 595 596 /* 597 * Descend on a tree 598 */ 599 600 fn = root; 601 602 for (;;) { 603 struct fib6_node *next; 604 605 dir = addr_bit_set(args->addr, fn->fn_bit); 606 607 next = dir ? fn->right : fn->left; 608 609 if (next) { 610 fn = next; 611 continue; 612 } 613 614 break; 615 } 616 617 while ((fn->fn_flags & RTN_ROOT) == 0) { 618 #ifdef CONFIG_IPV6_SUBTREES 619 if (fn->subtree) { 620 struct fib6_node *st; 621 struct lookup_args *narg; 622 623 narg = args + 1; 624 625 if (narg->addr) { 626 st = fib6_lookup_1(fn->subtree, narg); 627 628 if (st && !(st->fn_flags & RTN_ROOT)) 629 return st; 630 } 631 } 632 #endif 633 634 if (fn->fn_flags & RTN_RTINFO) { 635 struct rt6key *key; 636 637 key = (struct rt6key *) ((u8 *) fn->leaf + 638 args->offset); 639 640 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) 641 return fn; 642 } 643 644 fn = fn->parent; 645 } 646 647 return NULL; 648 } 649 650 struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr, 651 struct in6_addr *saddr) 652 { 653 struct lookup_args args[2]; 654 struct fib6_node *fn; 655 656 args[0].offset = offsetof(struct rt6_info, rt6i_dst); 657 args[0].addr = daddr; 658 659 #ifdef CONFIG_IPV6_SUBTREES 660 args[1].offset = offsetof(struct rt6_info, rt6i_src); 661 args[1].addr = saddr; 662 #endif 663 664 fn = fib6_lookup_1(root, args); 665 666 if (fn == NULL || fn->fn_flags & RTN_TL_ROOT) 667 fn = root; 668 669 return fn; 670 } 671 672 /* 673 * Get node with specified destination prefix (and source prefix, 674 * if subtrees are used) 675 */ 676 677 678 static struct fib6_node * fib6_locate_1(struct fib6_node *root, 679 struct in6_addr *addr, 680 int plen, int offset) 681 { 682 struct fib6_node *fn; 683 684 for (fn = root; fn ; ) { 685 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset); 686 687 /* 688 * Prefix match 689 */ 690 if (plen < fn->fn_bit || 691 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) 692 return NULL; 693 694 if (plen == fn->fn_bit) 695 return fn; 696 697 /* 698 * We have more bits to go 699 */ 700 if (addr_bit_set(addr, fn->fn_bit)) 701 fn = fn->right; 702 else 703 fn = fn->left; 704 } 705 return NULL; 706 } 707 708 struct fib6_node * fib6_locate(struct fib6_node *root, 709 struct in6_addr *daddr, int dst_len, 710 struct in6_addr *saddr, int src_len) 711 { 712 struct fib6_node *fn; 713 714 fn = fib6_locate_1(root, daddr, dst_len, 715 offsetof(struct rt6_info, rt6i_dst)); 716 717 #ifdef CONFIG_IPV6_SUBTREES 718 if (src_len) { 719 BUG_TRAP(saddr!=NULL); 720 if (fn == NULL) 721 fn = fn->subtree; 722 if (fn) 723 fn = fib6_locate_1(fn, saddr, src_len, 724 offsetof(struct rt6_info, rt6i_src)); 725 } 726 #endif 727 728 if (fn && fn->fn_flags&RTN_RTINFO) 729 return fn; 730 731 return NULL; 732 } 733 734 735 /* 736 * Deletion 737 * 738 */ 739 740 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn) 741 { 742 if (fn->fn_flags&RTN_ROOT) 743 return &ip6_null_entry; 744 745 while(fn) { 746 if(fn->left) 747 return fn->left->leaf; 748 749 if(fn->right) 750 return fn->right->leaf; 751 752 fn = SUBTREE(fn); 753 } 754 return NULL; 755 } 756 757 /* 758 * Called to trim the tree of intermediate nodes when possible. "fn" 759 * is the node we want to try and remove. 760 */ 761 762 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn) 763 { 764 int children; 765 int nstate; 766 struct fib6_node *child, *pn; 767 struct fib6_walker_t *w; 768 int iter = 0; 769 770 for (;;) { 771 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter); 772 iter++; 773 774 BUG_TRAP(!(fn->fn_flags&RTN_RTINFO)); 775 BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT)); 776 BUG_TRAP(fn->leaf==NULL); 777 778 children = 0; 779 child = NULL; 780 if (fn->right) child = fn->right, children |= 1; 781 if (fn->left) child = fn->left, children |= 2; 782 783 if (children == 3 || SUBTREE(fn) 784 #ifdef CONFIG_IPV6_SUBTREES 785 /* Subtree root (i.e. fn) may have one child */ 786 || (children && fn->fn_flags&RTN_ROOT) 787 #endif 788 ) { 789 fn->leaf = fib6_find_prefix(fn); 790 #if RT6_DEBUG >= 2 791 if (fn->leaf==NULL) { 792 BUG_TRAP(fn->leaf); 793 fn->leaf = &ip6_null_entry; 794 } 795 #endif 796 atomic_inc(&fn->leaf->rt6i_ref); 797 return fn->parent; 798 } 799 800 pn = fn->parent; 801 #ifdef CONFIG_IPV6_SUBTREES 802 if (SUBTREE(pn) == fn) { 803 BUG_TRAP(fn->fn_flags&RTN_ROOT); 804 SUBTREE(pn) = NULL; 805 nstate = FWS_L; 806 } else { 807 BUG_TRAP(!(fn->fn_flags&RTN_ROOT)); 808 #endif 809 if (pn->right == fn) pn->right = child; 810 else if (pn->left == fn) pn->left = child; 811 #if RT6_DEBUG >= 2 812 else BUG_TRAP(0); 813 #endif 814 if (child) 815 child->parent = pn; 816 nstate = FWS_R; 817 #ifdef CONFIG_IPV6_SUBTREES 818 } 819 #endif 820 821 read_lock(&fib6_walker_lock); 822 FOR_WALKERS(w) { 823 if (child == NULL) { 824 if (w->root == fn) { 825 w->root = w->node = NULL; 826 RT6_TRACE("W %p adjusted by delroot 1\n", w); 827 } else if (w->node == fn) { 828 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate); 829 w->node = pn; 830 w->state = nstate; 831 } 832 } else { 833 if (w->root == fn) { 834 w->root = child; 835 RT6_TRACE("W %p adjusted by delroot 2\n", w); 836 } 837 if (w->node == fn) { 838 w->node = child; 839 if (children&2) { 840 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); 841 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT; 842 } else { 843 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); 844 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT; 845 } 846 } 847 } 848 } 849 read_unlock(&fib6_walker_lock); 850 851 node_free(fn); 852 if (pn->fn_flags&RTN_RTINFO || SUBTREE(pn)) 853 return pn; 854 855 rt6_release(pn->leaf); 856 pn->leaf = NULL; 857 fn = pn; 858 } 859 } 860 861 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp, 862 struct nlmsghdr *nlh, void *_rtattr) 863 { 864 struct fib6_walker_t *w; 865 struct rt6_info *rt = *rtp; 866 867 RT6_TRACE("fib6_del_route\n"); 868 869 /* Unlink it */ 870 *rtp = rt->u.next; 871 rt->rt6i_node = NULL; 872 rt6_stats.fib_rt_entries--; 873 rt6_stats.fib_discarded_routes++; 874 875 /* Adjust walkers */ 876 read_lock(&fib6_walker_lock); 877 FOR_WALKERS(w) { 878 if (w->state == FWS_C && w->leaf == rt) { 879 RT6_TRACE("walker %p adjusted by delroute\n", w); 880 w->leaf = rt->u.next; 881 if (w->leaf == NULL) 882 w->state = FWS_U; 883 } 884 } 885 read_unlock(&fib6_walker_lock); 886 887 rt->u.next = NULL; 888 889 if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT) 890 fn->leaf = &ip6_null_entry; 891 892 /* If it was last route, expunge its radix tree node */ 893 if (fn->leaf == NULL) { 894 fn->fn_flags &= ~RTN_RTINFO; 895 rt6_stats.fib_route_nodes--; 896 fn = fib6_repair_tree(fn); 897 } 898 899 if (atomic_read(&rt->rt6i_ref) != 1) { 900 /* This route is used as dummy address holder in some split 901 * nodes. It is not leaked, but it still holds other resources, 902 * which must be released in time. So, scan ascendant nodes 903 * and replace dummy references to this route with references 904 * to still alive ones. 905 */ 906 while (fn) { 907 if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) { 908 fn->leaf = fib6_find_prefix(fn); 909 atomic_inc(&fn->leaf->rt6i_ref); 910 rt6_release(rt); 911 } 912 fn = fn->parent; 913 } 914 /* No more references are possible at this point. */ 915 if (atomic_read(&rt->rt6i_ref) != 1) BUG(); 916 } 917 918 inet6_rt_notify(RTM_DELROUTE, rt, nlh); 919 rt6_release(rt); 920 } 921 922 int fib6_del(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr) 923 { 924 struct fib6_node *fn = rt->rt6i_node; 925 struct rt6_info **rtp; 926 927 #if RT6_DEBUG >= 2 928 if (rt->u.dst.obsolete>0) { 929 BUG_TRAP(fn==NULL); 930 return -ENOENT; 931 } 932 #endif 933 if (fn == NULL || rt == &ip6_null_entry) 934 return -ENOENT; 935 936 BUG_TRAP(fn->fn_flags&RTN_RTINFO); 937 938 if (!(rt->rt6i_flags&RTF_CACHE)) 939 fib6_prune_clones(fn, rt); 940 941 /* 942 * Walk the leaf entries looking for ourself 943 */ 944 945 for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.next) { 946 if (*rtp == rt) { 947 fib6_del_route(fn, rtp, nlh, _rtattr); 948 return 0; 949 } 950 } 951 return -ENOENT; 952 } 953 954 /* 955 * Tree traversal function. 956 * 957 * Certainly, it is not interrupt safe. 958 * However, it is internally reenterable wrt itself and fib6_add/fib6_del. 959 * It means, that we can modify tree during walking 960 * and use this function for garbage collection, clone pruning, 961 * cleaning tree when a device goes down etc. etc. 962 * 963 * It guarantees that every node will be traversed, 964 * and that it will be traversed only once. 965 * 966 * Callback function w->func may return: 967 * 0 -> continue walking. 968 * positive value -> walking is suspended (used by tree dumps, 969 * and probably by gc, if it will be split to several slices) 970 * negative value -> terminate walking. 971 * 972 * The function itself returns: 973 * 0 -> walk is complete. 974 * >0 -> walk is incomplete (i.e. suspended) 975 * <0 -> walk is terminated by an error. 976 */ 977 978 int fib6_walk_continue(struct fib6_walker_t *w) 979 { 980 struct fib6_node *fn, *pn; 981 982 for (;;) { 983 fn = w->node; 984 if (fn == NULL) 985 return 0; 986 987 if (w->prune && fn != w->root && 988 fn->fn_flags&RTN_RTINFO && w->state < FWS_C) { 989 w->state = FWS_C; 990 w->leaf = fn->leaf; 991 } 992 switch (w->state) { 993 #ifdef CONFIG_IPV6_SUBTREES 994 case FWS_S: 995 if (SUBTREE(fn)) { 996 w->node = SUBTREE(fn); 997 continue; 998 } 999 w->state = FWS_L; 1000 #endif 1001 case FWS_L: 1002 if (fn->left) { 1003 w->node = fn->left; 1004 w->state = FWS_INIT; 1005 continue; 1006 } 1007 w->state = FWS_R; 1008 case FWS_R: 1009 if (fn->right) { 1010 w->node = fn->right; 1011 w->state = FWS_INIT; 1012 continue; 1013 } 1014 w->state = FWS_C; 1015 w->leaf = fn->leaf; 1016 case FWS_C: 1017 if (w->leaf && fn->fn_flags&RTN_RTINFO) { 1018 int err = w->func(w); 1019 if (err) 1020 return err; 1021 continue; 1022 } 1023 w->state = FWS_U; 1024 case FWS_U: 1025 if (fn == w->root) 1026 return 0; 1027 pn = fn->parent; 1028 w->node = pn; 1029 #ifdef CONFIG_IPV6_SUBTREES 1030 if (SUBTREE(pn) == fn) { 1031 BUG_TRAP(fn->fn_flags&RTN_ROOT); 1032 w->state = FWS_L; 1033 continue; 1034 } 1035 #endif 1036 if (pn->left == fn) { 1037 w->state = FWS_R; 1038 continue; 1039 } 1040 if (pn->right == fn) { 1041 w->state = FWS_C; 1042 w->leaf = w->node->leaf; 1043 continue; 1044 } 1045 #if RT6_DEBUG >= 2 1046 BUG_TRAP(0); 1047 #endif 1048 } 1049 } 1050 } 1051 1052 int fib6_walk(struct fib6_walker_t *w) 1053 { 1054 int res; 1055 1056 w->state = FWS_INIT; 1057 w->node = w->root; 1058 1059 fib6_walker_link(w); 1060 res = fib6_walk_continue(w); 1061 if (res <= 0) 1062 fib6_walker_unlink(w); 1063 return res; 1064 } 1065 1066 static int fib6_clean_node(struct fib6_walker_t *w) 1067 { 1068 int res; 1069 struct rt6_info *rt; 1070 struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w; 1071 1072 for (rt = w->leaf; rt; rt = rt->u.next) { 1073 res = c->func(rt, c->arg); 1074 if (res < 0) { 1075 w->leaf = rt; 1076 res = fib6_del(rt, NULL, NULL); 1077 if (res) { 1078 #if RT6_DEBUG >= 2 1079 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res); 1080 #endif 1081 continue; 1082 } 1083 return 0; 1084 } 1085 BUG_TRAP(res==0); 1086 } 1087 w->leaf = rt; 1088 return 0; 1089 } 1090 1091 /* 1092 * Convenient frontend to tree walker. 1093 * 1094 * func is called on each route. 1095 * It may return -1 -> delete this route. 1096 * 0 -> continue walking 1097 * 1098 * prune==1 -> only immediate children of node (certainly, 1099 * ignoring pure split nodes) will be scanned. 1100 */ 1101 1102 void fib6_clean_tree(struct fib6_node *root, 1103 int (*func)(struct rt6_info *, void *arg), 1104 int prune, void *arg) 1105 { 1106 struct fib6_cleaner_t c; 1107 1108 c.w.root = root; 1109 c.w.func = fib6_clean_node; 1110 c.w.prune = prune; 1111 c.func = func; 1112 c.arg = arg; 1113 1114 fib6_walk(&c.w); 1115 } 1116 1117 static int fib6_prune_clone(struct rt6_info *rt, void *arg) 1118 { 1119 if (rt->rt6i_flags & RTF_CACHE) { 1120 RT6_TRACE("pruning clone %p\n", rt); 1121 return -1; 1122 } 1123 1124 return 0; 1125 } 1126 1127 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt) 1128 { 1129 fib6_clean_tree(fn, fib6_prune_clone, 1, rt); 1130 } 1131 1132 /* 1133 * Garbage collection 1134 */ 1135 1136 static struct fib6_gc_args 1137 { 1138 int timeout; 1139 int more; 1140 } gc_args; 1141 1142 static int fib6_age(struct rt6_info *rt, void *arg) 1143 { 1144 unsigned long now = jiffies; 1145 1146 /* 1147 * check addrconf expiration here. 1148 * Routes are expired even if they are in use. 1149 * 1150 * Also age clones. Note, that clones are aged out 1151 * only if they are not in use now. 1152 */ 1153 1154 if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) { 1155 if (time_after(now, rt->rt6i_expires)) { 1156 RT6_TRACE("expiring %p\n", rt); 1157 rt6_reset_dflt_pointer(rt); 1158 return -1; 1159 } 1160 gc_args.more++; 1161 } else if (rt->rt6i_flags & RTF_CACHE) { 1162 if (atomic_read(&rt->u.dst.__refcnt) == 0 && 1163 time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) { 1164 RT6_TRACE("aging clone %p\n", rt); 1165 return -1; 1166 } else if ((rt->rt6i_flags & RTF_GATEWAY) && 1167 (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) { 1168 RT6_TRACE("purging route %p via non-router but gateway\n", 1169 rt); 1170 return -1; 1171 } 1172 gc_args.more++; 1173 } 1174 1175 return 0; 1176 } 1177 1178 static DEFINE_SPINLOCK(fib6_gc_lock); 1179 1180 void fib6_run_gc(unsigned long dummy) 1181 { 1182 if (dummy != ~0UL) { 1183 spin_lock_bh(&fib6_gc_lock); 1184 gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval; 1185 } else { 1186 local_bh_disable(); 1187 if (!spin_trylock(&fib6_gc_lock)) { 1188 mod_timer(&ip6_fib_timer, jiffies + HZ); 1189 local_bh_enable(); 1190 return; 1191 } 1192 gc_args.timeout = ip6_rt_gc_interval; 1193 } 1194 gc_args.more = 0; 1195 1196 1197 write_lock_bh(&rt6_lock); 1198 ndisc_dst_gc(&gc_args.more); 1199 fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL); 1200 write_unlock_bh(&rt6_lock); 1201 1202 if (gc_args.more) 1203 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); 1204 else { 1205 del_timer(&ip6_fib_timer); 1206 ip6_fib_timer.expires = 0; 1207 } 1208 spin_unlock_bh(&fib6_gc_lock); 1209 } 1210 1211 void __init fib6_init(void) 1212 { 1213 fib6_node_kmem = kmem_cache_create("fib6_nodes", 1214 sizeof(struct fib6_node), 1215 0, SLAB_HWCACHE_ALIGN, 1216 NULL, NULL); 1217 if (!fib6_node_kmem) 1218 panic("cannot create fib6_nodes cache"); 1219 } 1220 1221 void fib6_gc_cleanup(void) 1222 { 1223 del_timer(&ip6_fib_timer); 1224 kmem_cache_destroy(fib6_node_kmem); 1225 } 1226