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 * Ville Nuorvala: Fixed routing subtrees. 22 */ 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 #include <linux/list.h> 31 32 #ifdef CONFIG_PROC_FS 33 #include <linux/proc_fs.h> 34 #endif 35 36 #include <net/ipv6.h> 37 #include <net/ndisc.h> 38 #include <net/addrconf.h> 39 40 #include <net/ip6_fib.h> 41 #include <net/ip6_route.h> 42 43 #define RT6_DEBUG 2 44 45 #if RT6_DEBUG >= 3 46 #define RT6_TRACE(x...) printk(KERN_DEBUG x) 47 #else 48 #define RT6_TRACE(x...) do { ; } while (0) 49 #endif 50 51 struct rt6_statistics rt6_stats; 52 53 static struct kmem_cache * fib6_node_kmem __read_mostly; 54 55 enum fib_walk_state_t 56 { 57 #ifdef CONFIG_IPV6_SUBTREES 58 FWS_S, 59 #endif 60 FWS_L, 61 FWS_R, 62 FWS_C, 63 FWS_U 64 }; 65 66 struct fib6_cleaner_t 67 { 68 struct fib6_walker_t w; 69 int (*func)(struct rt6_info *, void *arg); 70 void *arg; 71 }; 72 73 static DEFINE_RWLOCK(fib6_walker_lock); 74 75 #ifdef CONFIG_IPV6_SUBTREES 76 #define FWS_INIT FWS_S 77 #else 78 #define FWS_INIT FWS_L 79 #endif 80 81 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt); 82 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn); 83 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn); 84 static int fib6_walk(struct fib6_walker_t *w); 85 static int fib6_walk_continue(struct fib6_walker_t *w); 86 87 /* 88 * A routing update causes an increase of the serial number on the 89 * affected subtree. This allows for cached routes to be asynchronously 90 * tested when modifications are made to the destination cache as a 91 * result of redirects, path MTU changes, etc. 92 */ 93 94 static __u32 rt_sernum; 95 96 static DEFINE_TIMER(ip6_fib_timer, fib6_run_gc, 0, 0); 97 98 static struct fib6_walker_t fib6_walker_list = { 99 .prev = &fib6_walker_list, 100 .next = &fib6_walker_list, 101 }; 102 103 #define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next) 104 105 static inline void fib6_walker_link(struct fib6_walker_t *w) 106 { 107 write_lock_bh(&fib6_walker_lock); 108 w->next = fib6_walker_list.next; 109 w->prev = &fib6_walker_list; 110 w->next->prev = w; 111 w->prev->next = w; 112 write_unlock_bh(&fib6_walker_lock); 113 } 114 115 static inline void fib6_walker_unlink(struct fib6_walker_t *w) 116 { 117 write_lock_bh(&fib6_walker_lock); 118 w->next->prev = w->prev; 119 w->prev->next = w->next; 120 w->prev = w->next = w; 121 write_unlock_bh(&fib6_walker_lock); 122 } 123 static __inline__ u32 fib6_new_sernum(void) 124 { 125 u32 n = ++rt_sernum; 126 if ((__s32)n <= 0) 127 rt_sernum = n = 1; 128 return n; 129 } 130 131 /* 132 * Auxiliary address test functions for the radix tree. 133 * 134 * These assume a 32bit processor (although it will work on 135 * 64bit processors) 136 */ 137 138 /* 139 * test bit 140 */ 141 142 static __inline__ __be32 addr_bit_set(void *token, int fn_bit) 143 { 144 __be32 *addr = token; 145 146 return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5]; 147 } 148 149 static __inline__ struct fib6_node * node_alloc(void) 150 { 151 struct fib6_node *fn; 152 153 fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC); 154 155 return fn; 156 } 157 158 static __inline__ void node_free(struct fib6_node * fn) 159 { 160 kmem_cache_free(fib6_node_kmem, fn); 161 } 162 163 static __inline__ void rt6_release(struct rt6_info *rt) 164 { 165 if (atomic_dec_and_test(&rt->rt6i_ref)) 166 dst_free(&rt->u.dst); 167 } 168 169 static struct fib6_table fib6_main_tbl = { 170 .tb6_id = RT6_TABLE_MAIN, 171 .tb6_root = { 172 .leaf = &ip6_null_entry, 173 .fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO, 174 }, 175 }; 176 177 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 178 #define FIB_TABLE_HASHSZ 256 179 #else 180 #define FIB_TABLE_HASHSZ 1 181 #endif 182 static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ]; 183 184 static void fib6_link_table(struct fib6_table *tb) 185 { 186 unsigned int h; 187 188 /* 189 * Initialize table lock at a single place to give lockdep a key, 190 * tables aren't visible prior to being linked to the list. 191 */ 192 rwlock_init(&tb->tb6_lock); 193 194 h = tb->tb6_id & (FIB_TABLE_HASHSZ - 1); 195 196 /* 197 * No protection necessary, this is the only list mutatation 198 * operation, tables never disappear once they exist. 199 */ 200 hlist_add_head_rcu(&tb->tb6_hlist, &fib_table_hash[h]); 201 } 202 203 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 204 static struct fib6_table fib6_local_tbl = { 205 .tb6_id = RT6_TABLE_LOCAL, 206 .tb6_root = { 207 .leaf = &ip6_null_entry, 208 .fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO, 209 }, 210 }; 211 212 static struct fib6_table *fib6_alloc_table(u32 id) 213 { 214 struct fib6_table *table; 215 216 table = kzalloc(sizeof(*table), GFP_ATOMIC); 217 if (table != NULL) { 218 table->tb6_id = id; 219 table->tb6_root.leaf = &ip6_null_entry; 220 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO; 221 } 222 223 return table; 224 } 225 226 struct fib6_table *fib6_new_table(u32 id) 227 { 228 struct fib6_table *tb; 229 230 if (id == 0) 231 id = RT6_TABLE_MAIN; 232 tb = fib6_get_table(id); 233 if (tb) 234 return tb; 235 236 tb = fib6_alloc_table(id); 237 if (tb != NULL) 238 fib6_link_table(tb); 239 240 return tb; 241 } 242 243 struct fib6_table *fib6_get_table(u32 id) 244 { 245 struct fib6_table *tb; 246 struct hlist_node *node; 247 unsigned int h; 248 249 if (id == 0) 250 id = RT6_TABLE_MAIN; 251 h = id & (FIB_TABLE_HASHSZ - 1); 252 rcu_read_lock(); 253 hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb6_hlist) { 254 if (tb->tb6_id == id) { 255 rcu_read_unlock(); 256 return tb; 257 } 258 } 259 rcu_read_unlock(); 260 261 return NULL; 262 } 263 264 static void __init fib6_tables_init(void) 265 { 266 fib6_link_table(&fib6_main_tbl); 267 fib6_link_table(&fib6_local_tbl); 268 } 269 270 #else 271 272 struct fib6_table *fib6_new_table(u32 id) 273 { 274 return fib6_get_table(id); 275 } 276 277 struct fib6_table *fib6_get_table(u32 id) 278 { 279 return &fib6_main_tbl; 280 } 281 282 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags, 283 pol_lookup_t lookup) 284 { 285 return (struct dst_entry *) lookup(&fib6_main_tbl, fl, flags); 286 } 287 288 static void __init fib6_tables_init(void) 289 { 290 fib6_link_table(&fib6_main_tbl); 291 } 292 293 #endif 294 295 static int fib6_dump_node(struct fib6_walker_t *w) 296 { 297 int res; 298 struct rt6_info *rt; 299 300 for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) { 301 res = rt6_dump_route(rt, w->args); 302 if (res < 0) { 303 /* Frame is full, suspend walking */ 304 w->leaf = rt; 305 return 1; 306 } 307 BUG_TRAP(res!=0); 308 } 309 w->leaf = NULL; 310 return 0; 311 } 312 313 static void fib6_dump_end(struct netlink_callback *cb) 314 { 315 struct fib6_walker_t *w = (void*)cb->args[2]; 316 317 if (w) { 318 cb->args[2] = 0; 319 kfree(w); 320 } 321 cb->done = (void*)cb->args[3]; 322 cb->args[1] = 3; 323 } 324 325 static int fib6_dump_done(struct netlink_callback *cb) 326 { 327 fib6_dump_end(cb); 328 return cb->done ? cb->done(cb) : 0; 329 } 330 331 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb, 332 struct netlink_callback *cb) 333 { 334 struct fib6_walker_t *w; 335 int res; 336 337 w = (void *)cb->args[2]; 338 w->root = &table->tb6_root; 339 340 if (cb->args[4] == 0) { 341 read_lock_bh(&table->tb6_lock); 342 res = fib6_walk(w); 343 read_unlock_bh(&table->tb6_lock); 344 if (res > 0) 345 cb->args[4] = 1; 346 } else { 347 read_lock_bh(&table->tb6_lock); 348 res = fib6_walk_continue(w); 349 read_unlock_bh(&table->tb6_lock); 350 if (res != 0) { 351 if (res < 0) 352 fib6_walker_unlink(w); 353 goto end; 354 } 355 fib6_walker_unlink(w); 356 cb->args[4] = 0; 357 } 358 end: 359 return res; 360 } 361 362 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) 363 { 364 unsigned int h, s_h; 365 unsigned int e = 0, s_e; 366 struct rt6_rtnl_dump_arg arg; 367 struct fib6_walker_t *w; 368 struct fib6_table *tb; 369 struct hlist_node *node; 370 int res = 0; 371 372 s_h = cb->args[0]; 373 s_e = cb->args[1]; 374 375 w = (void *)cb->args[2]; 376 if (w == NULL) { 377 /* New dump: 378 * 379 * 1. hook callback destructor. 380 */ 381 cb->args[3] = (long)cb->done; 382 cb->done = fib6_dump_done; 383 384 /* 385 * 2. allocate and initialize walker. 386 */ 387 w = kzalloc(sizeof(*w), GFP_ATOMIC); 388 if (w == NULL) 389 return -ENOMEM; 390 w->func = fib6_dump_node; 391 cb->args[2] = (long)w; 392 } 393 394 arg.skb = skb; 395 arg.cb = cb; 396 w->args = &arg; 397 398 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) { 399 e = 0; 400 hlist_for_each_entry(tb, node, &fib_table_hash[h], tb6_hlist) { 401 if (e < s_e) 402 goto next; 403 res = fib6_dump_table(tb, skb, cb); 404 if (res != 0) 405 goto out; 406 next: 407 e++; 408 } 409 } 410 out: 411 cb->args[1] = e; 412 cb->args[0] = h; 413 414 res = res < 0 ? res : skb->len; 415 if (res <= 0) 416 fib6_dump_end(cb); 417 return res; 418 } 419 420 /* 421 * Routing Table 422 * 423 * return the appropriate node for a routing tree "add" operation 424 * by either creating and inserting or by returning an existing 425 * node. 426 */ 427 428 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, 429 int addrlen, int plen, 430 int offset) 431 { 432 struct fib6_node *fn, *in, *ln; 433 struct fib6_node *pn = NULL; 434 struct rt6key *key; 435 int bit; 436 __be32 dir = 0; 437 __u32 sernum = fib6_new_sernum(); 438 439 RT6_TRACE("fib6_add_1\n"); 440 441 /* insert node in tree */ 442 443 fn = root; 444 445 do { 446 key = (struct rt6key *)((u8 *)fn->leaf + offset); 447 448 /* 449 * Prefix match 450 */ 451 if (plen < fn->fn_bit || 452 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) 453 goto insert_above; 454 455 /* 456 * Exact match ? 457 */ 458 459 if (plen == fn->fn_bit) { 460 /* clean up an intermediate node */ 461 if ((fn->fn_flags & RTN_RTINFO) == 0) { 462 rt6_release(fn->leaf); 463 fn->leaf = NULL; 464 } 465 466 fn->fn_sernum = sernum; 467 468 return fn; 469 } 470 471 /* 472 * We have more bits to go 473 */ 474 475 /* Try to walk down on tree. */ 476 fn->fn_sernum = sernum; 477 dir = addr_bit_set(addr, fn->fn_bit); 478 pn = fn; 479 fn = dir ? fn->right: fn->left; 480 } while (fn); 481 482 /* 483 * We walked to the bottom of tree. 484 * Create new leaf node without children. 485 */ 486 487 ln = node_alloc(); 488 489 if (ln == NULL) 490 return NULL; 491 ln->fn_bit = plen; 492 493 ln->parent = pn; 494 ln->fn_sernum = sernum; 495 496 if (dir) 497 pn->right = ln; 498 else 499 pn->left = ln; 500 501 return ln; 502 503 504 insert_above: 505 /* 506 * split since we don't have a common prefix anymore or 507 * we have a less significant route. 508 * we've to insert an intermediate node on the list 509 * this new node will point to the one we need to create 510 * and the current 511 */ 512 513 pn = fn->parent; 514 515 /* find 1st bit in difference between the 2 addrs. 516 517 See comment in __ipv6_addr_diff: bit may be an invalid value, 518 but if it is >= plen, the value is ignored in any case. 519 */ 520 521 bit = __ipv6_addr_diff(addr, &key->addr, addrlen); 522 523 /* 524 * (intermediate)[in] 525 * / \ 526 * (new leaf node)[ln] (old node)[fn] 527 */ 528 if (plen > bit) { 529 in = node_alloc(); 530 ln = node_alloc(); 531 532 if (in == NULL || ln == NULL) { 533 if (in) 534 node_free(in); 535 if (ln) 536 node_free(ln); 537 return NULL; 538 } 539 540 /* 541 * new intermediate node. 542 * RTN_RTINFO will 543 * be off since that an address that chooses one of 544 * the branches would not match less specific routes 545 * in the other branch 546 */ 547 548 in->fn_bit = bit; 549 550 in->parent = pn; 551 in->leaf = fn->leaf; 552 atomic_inc(&in->leaf->rt6i_ref); 553 554 in->fn_sernum = sernum; 555 556 /* update parent pointer */ 557 if (dir) 558 pn->right = in; 559 else 560 pn->left = in; 561 562 ln->fn_bit = plen; 563 564 ln->parent = in; 565 fn->parent = in; 566 567 ln->fn_sernum = sernum; 568 569 if (addr_bit_set(addr, bit)) { 570 in->right = ln; 571 in->left = fn; 572 } else { 573 in->left = ln; 574 in->right = fn; 575 } 576 } else { /* plen <= bit */ 577 578 /* 579 * (new leaf node)[ln] 580 * / \ 581 * (old node)[fn] NULL 582 */ 583 584 ln = node_alloc(); 585 586 if (ln == NULL) 587 return NULL; 588 589 ln->fn_bit = plen; 590 591 ln->parent = pn; 592 593 ln->fn_sernum = sernum; 594 595 if (dir) 596 pn->right = ln; 597 else 598 pn->left = ln; 599 600 if (addr_bit_set(&key->addr, plen)) 601 ln->right = fn; 602 else 603 ln->left = fn; 604 605 fn->parent = ln; 606 } 607 return ln; 608 } 609 610 /* 611 * Insert routing information in a node. 612 */ 613 614 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 615 struct nl_info *info) 616 { 617 struct rt6_info *iter = NULL; 618 struct rt6_info **ins; 619 620 ins = &fn->leaf; 621 622 if (fn->fn_flags&RTN_TL_ROOT && 623 fn->leaf == &ip6_null_entry && 624 !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){ 625 fn->leaf = rt; 626 rt->u.dst.rt6_next = NULL; 627 goto out; 628 } 629 630 for (iter = fn->leaf; iter; iter=iter->u.dst.rt6_next) { 631 /* 632 * Search for duplicates 633 */ 634 635 if (iter->rt6i_metric == rt->rt6i_metric) { 636 /* 637 * Same priority level 638 */ 639 640 if (iter->rt6i_dev == rt->rt6i_dev && 641 iter->rt6i_idev == rt->rt6i_idev && 642 ipv6_addr_equal(&iter->rt6i_gateway, 643 &rt->rt6i_gateway)) { 644 if (!(iter->rt6i_flags&RTF_EXPIRES)) 645 return -EEXIST; 646 iter->rt6i_expires = rt->rt6i_expires; 647 if (!(rt->rt6i_flags&RTF_EXPIRES)) { 648 iter->rt6i_flags &= ~RTF_EXPIRES; 649 iter->rt6i_expires = 0; 650 } 651 return -EEXIST; 652 } 653 } 654 655 if (iter->rt6i_metric > rt->rt6i_metric) 656 break; 657 658 ins = &iter->u.dst.rt6_next; 659 } 660 661 /* Reset round-robin state, if necessary */ 662 if (ins == &fn->leaf) 663 fn->rr_ptr = NULL; 664 665 /* 666 * insert node 667 */ 668 669 out: 670 rt->u.dst.rt6_next = iter; 671 *ins = rt; 672 rt->rt6i_node = fn; 673 atomic_inc(&rt->rt6i_ref); 674 inet6_rt_notify(RTM_NEWROUTE, rt, info); 675 rt6_stats.fib_rt_entries++; 676 677 if ((fn->fn_flags & RTN_RTINFO) == 0) { 678 rt6_stats.fib_route_nodes++; 679 fn->fn_flags |= RTN_RTINFO; 680 } 681 682 return 0; 683 } 684 685 static __inline__ void fib6_start_gc(struct rt6_info *rt) 686 { 687 if (ip6_fib_timer.expires == 0 && 688 (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE))) 689 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); 690 } 691 692 void fib6_force_start_gc(void) 693 { 694 if (ip6_fib_timer.expires == 0) 695 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); 696 } 697 698 /* 699 * Add routing information to the routing tree. 700 * <destination addr>/<source addr> 701 * with source addr info in sub-trees 702 */ 703 704 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) 705 { 706 struct fib6_node *fn, *pn = NULL; 707 int err = -ENOMEM; 708 709 fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr), 710 rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst)); 711 712 if (fn == NULL) 713 goto out; 714 715 pn = fn; 716 717 #ifdef CONFIG_IPV6_SUBTREES 718 if (rt->rt6i_src.plen) { 719 struct fib6_node *sn; 720 721 if (fn->subtree == NULL) { 722 struct fib6_node *sfn; 723 724 /* 725 * Create subtree. 726 * 727 * fn[main tree] 728 * | 729 * sfn[subtree root] 730 * \ 731 * sn[new leaf node] 732 */ 733 734 /* Create subtree root node */ 735 sfn = node_alloc(); 736 if (sfn == NULL) 737 goto st_failure; 738 739 sfn->leaf = &ip6_null_entry; 740 atomic_inc(&ip6_null_entry.rt6i_ref); 741 sfn->fn_flags = RTN_ROOT; 742 sfn->fn_sernum = fib6_new_sernum(); 743 744 /* Now add the first leaf node to new subtree */ 745 746 sn = fib6_add_1(sfn, &rt->rt6i_src.addr, 747 sizeof(struct in6_addr), rt->rt6i_src.plen, 748 offsetof(struct rt6_info, rt6i_src)); 749 750 if (sn == NULL) { 751 /* If it is failed, discard just allocated 752 root, and then (in st_failure) stale node 753 in main tree. 754 */ 755 node_free(sfn); 756 goto st_failure; 757 } 758 759 /* Now link new subtree to main tree */ 760 sfn->parent = fn; 761 fn->subtree = sfn; 762 } else { 763 sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr, 764 sizeof(struct in6_addr), rt->rt6i_src.plen, 765 offsetof(struct rt6_info, rt6i_src)); 766 767 if (sn == NULL) 768 goto st_failure; 769 } 770 771 if (fn->leaf == NULL) { 772 fn->leaf = rt; 773 atomic_inc(&rt->rt6i_ref); 774 } 775 fn = sn; 776 } 777 #endif 778 779 err = fib6_add_rt2node(fn, rt, info); 780 781 if (err == 0) { 782 fib6_start_gc(rt); 783 if (!(rt->rt6i_flags&RTF_CACHE)) 784 fib6_prune_clones(pn, rt); 785 } 786 787 out: 788 if (err) { 789 #ifdef CONFIG_IPV6_SUBTREES 790 /* 791 * If fib6_add_1 has cleared the old leaf pointer in the 792 * super-tree leaf node we have to find a new one for it. 793 */ 794 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) { 795 pn->leaf = fib6_find_prefix(pn); 796 #if RT6_DEBUG >= 2 797 if (!pn->leaf) { 798 BUG_TRAP(pn->leaf != NULL); 799 pn->leaf = &ip6_null_entry; 800 } 801 #endif 802 atomic_inc(&pn->leaf->rt6i_ref); 803 } 804 #endif 805 dst_free(&rt->u.dst); 806 } 807 return err; 808 809 #ifdef CONFIG_IPV6_SUBTREES 810 /* Subtree creation failed, probably main tree node 811 is orphan. If it is, shoot it. 812 */ 813 st_failure: 814 if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT))) 815 fib6_repair_tree(fn); 816 dst_free(&rt->u.dst); 817 return err; 818 #endif 819 } 820 821 /* 822 * Routing tree lookup 823 * 824 */ 825 826 struct lookup_args { 827 int offset; /* key offset on rt6_info */ 828 struct in6_addr *addr; /* search key */ 829 }; 830 831 static struct fib6_node * fib6_lookup_1(struct fib6_node *root, 832 struct lookup_args *args) 833 { 834 struct fib6_node *fn; 835 __be32 dir; 836 837 if (unlikely(args->offset == 0)) 838 return NULL; 839 840 /* 841 * Descend on a tree 842 */ 843 844 fn = root; 845 846 for (;;) { 847 struct fib6_node *next; 848 849 dir = addr_bit_set(args->addr, fn->fn_bit); 850 851 next = dir ? fn->right : fn->left; 852 853 if (next) { 854 fn = next; 855 continue; 856 } 857 858 break; 859 } 860 861 while(fn) { 862 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) { 863 struct rt6key *key; 864 865 key = (struct rt6key *) ((u8 *) fn->leaf + 866 args->offset); 867 868 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) { 869 #ifdef CONFIG_IPV6_SUBTREES 870 if (fn->subtree) 871 fn = fib6_lookup_1(fn->subtree, args + 1); 872 #endif 873 if (!fn || fn->fn_flags & RTN_RTINFO) 874 return fn; 875 } 876 } 877 878 if (fn->fn_flags & RTN_ROOT) 879 break; 880 881 fn = fn->parent; 882 } 883 884 return NULL; 885 } 886 887 struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr, 888 struct in6_addr *saddr) 889 { 890 struct fib6_node *fn; 891 struct lookup_args args[] = { 892 { 893 .offset = offsetof(struct rt6_info, rt6i_dst), 894 .addr = daddr, 895 }, 896 #ifdef CONFIG_IPV6_SUBTREES 897 { 898 .offset = offsetof(struct rt6_info, rt6i_src), 899 .addr = saddr, 900 }, 901 #endif 902 { 903 .offset = 0, /* sentinel */ 904 } 905 }; 906 907 fn = fib6_lookup_1(root, daddr ? args : args + 1); 908 909 if (fn == NULL || fn->fn_flags & RTN_TL_ROOT) 910 fn = root; 911 912 return fn; 913 } 914 915 /* 916 * Get node with specified destination prefix (and source prefix, 917 * if subtrees are used) 918 */ 919 920 921 static struct fib6_node * fib6_locate_1(struct fib6_node *root, 922 struct in6_addr *addr, 923 int plen, int offset) 924 { 925 struct fib6_node *fn; 926 927 for (fn = root; fn ; ) { 928 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset); 929 930 /* 931 * Prefix match 932 */ 933 if (plen < fn->fn_bit || 934 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) 935 return NULL; 936 937 if (plen == fn->fn_bit) 938 return fn; 939 940 /* 941 * We have more bits to go 942 */ 943 if (addr_bit_set(addr, fn->fn_bit)) 944 fn = fn->right; 945 else 946 fn = fn->left; 947 } 948 return NULL; 949 } 950 951 struct fib6_node * fib6_locate(struct fib6_node *root, 952 struct in6_addr *daddr, int dst_len, 953 struct in6_addr *saddr, int src_len) 954 { 955 struct fib6_node *fn; 956 957 fn = fib6_locate_1(root, daddr, dst_len, 958 offsetof(struct rt6_info, rt6i_dst)); 959 960 #ifdef CONFIG_IPV6_SUBTREES 961 if (src_len) { 962 BUG_TRAP(saddr!=NULL); 963 if (fn && fn->subtree) 964 fn = fib6_locate_1(fn->subtree, saddr, src_len, 965 offsetof(struct rt6_info, rt6i_src)); 966 } 967 #endif 968 969 if (fn && fn->fn_flags&RTN_RTINFO) 970 return fn; 971 972 return NULL; 973 } 974 975 976 /* 977 * Deletion 978 * 979 */ 980 981 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn) 982 { 983 if (fn->fn_flags&RTN_ROOT) 984 return &ip6_null_entry; 985 986 while(fn) { 987 if(fn->left) 988 return fn->left->leaf; 989 990 if(fn->right) 991 return fn->right->leaf; 992 993 fn = FIB6_SUBTREE(fn); 994 } 995 return NULL; 996 } 997 998 /* 999 * Called to trim the tree of intermediate nodes when possible. "fn" 1000 * is the node we want to try and remove. 1001 */ 1002 1003 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn) 1004 { 1005 int children; 1006 int nstate; 1007 struct fib6_node *child, *pn; 1008 struct fib6_walker_t *w; 1009 int iter = 0; 1010 1011 for (;;) { 1012 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter); 1013 iter++; 1014 1015 BUG_TRAP(!(fn->fn_flags&RTN_RTINFO)); 1016 BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT)); 1017 BUG_TRAP(fn->leaf==NULL); 1018 1019 children = 0; 1020 child = NULL; 1021 if (fn->right) child = fn->right, children |= 1; 1022 if (fn->left) child = fn->left, children |= 2; 1023 1024 if (children == 3 || FIB6_SUBTREE(fn) 1025 #ifdef CONFIG_IPV6_SUBTREES 1026 /* Subtree root (i.e. fn) may have one child */ 1027 || (children && fn->fn_flags&RTN_ROOT) 1028 #endif 1029 ) { 1030 fn->leaf = fib6_find_prefix(fn); 1031 #if RT6_DEBUG >= 2 1032 if (fn->leaf==NULL) { 1033 BUG_TRAP(fn->leaf); 1034 fn->leaf = &ip6_null_entry; 1035 } 1036 #endif 1037 atomic_inc(&fn->leaf->rt6i_ref); 1038 return fn->parent; 1039 } 1040 1041 pn = fn->parent; 1042 #ifdef CONFIG_IPV6_SUBTREES 1043 if (FIB6_SUBTREE(pn) == fn) { 1044 BUG_TRAP(fn->fn_flags&RTN_ROOT); 1045 FIB6_SUBTREE(pn) = NULL; 1046 nstate = FWS_L; 1047 } else { 1048 BUG_TRAP(!(fn->fn_flags&RTN_ROOT)); 1049 #endif 1050 if (pn->right == fn) pn->right = child; 1051 else if (pn->left == fn) pn->left = child; 1052 #if RT6_DEBUG >= 2 1053 else BUG_TRAP(0); 1054 #endif 1055 if (child) 1056 child->parent = pn; 1057 nstate = FWS_R; 1058 #ifdef CONFIG_IPV6_SUBTREES 1059 } 1060 #endif 1061 1062 read_lock(&fib6_walker_lock); 1063 FOR_WALKERS(w) { 1064 if (child == NULL) { 1065 if (w->root == fn) { 1066 w->root = w->node = NULL; 1067 RT6_TRACE("W %p adjusted by delroot 1\n", w); 1068 } else if (w->node == fn) { 1069 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate); 1070 w->node = pn; 1071 w->state = nstate; 1072 } 1073 } else { 1074 if (w->root == fn) { 1075 w->root = child; 1076 RT6_TRACE("W %p adjusted by delroot 2\n", w); 1077 } 1078 if (w->node == fn) { 1079 w->node = child; 1080 if (children&2) { 1081 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); 1082 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT; 1083 } else { 1084 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); 1085 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT; 1086 } 1087 } 1088 } 1089 } 1090 read_unlock(&fib6_walker_lock); 1091 1092 node_free(fn); 1093 if (pn->fn_flags&RTN_RTINFO || FIB6_SUBTREE(pn)) 1094 return pn; 1095 1096 rt6_release(pn->leaf); 1097 pn->leaf = NULL; 1098 fn = pn; 1099 } 1100 } 1101 1102 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp, 1103 struct nl_info *info) 1104 { 1105 struct fib6_walker_t *w; 1106 struct rt6_info *rt = *rtp; 1107 1108 RT6_TRACE("fib6_del_route\n"); 1109 1110 /* Unlink it */ 1111 *rtp = rt->u.dst.rt6_next; 1112 rt->rt6i_node = NULL; 1113 rt6_stats.fib_rt_entries--; 1114 rt6_stats.fib_discarded_routes++; 1115 1116 /* Reset round-robin state, if necessary */ 1117 if (fn->rr_ptr == rt) 1118 fn->rr_ptr = NULL; 1119 1120 /* Adjust walkers */ 1121 read_lock(&fib6_walker_lock); 1122 FOR_WALKERS(w) { 1123 if (w->state == FWS_C && w->leaf == rt) { 1124 RT6_TRACE("walker %p adjusted by delroute\n", w); 1125 w->leaf = rt->u.dst.rt6_next; 1126 if (w->leaf == NULL) 1127 w->state = FWS_U; 1128 } 1129 } 1130 read_unlock(&fib6_walker_lock); 1131 1132 rt->u.dst.rt6_next = NULL; 1133 1134 if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT) 1135 fn->leaf = &ip6_null_entry; 1136 1137 /* If it was last route, expunge its radix tree node */ 1138 if (fn->leaf == NULL) { 1139 fn->fn_flags &= ~RTN_RTINFO; 1140 rt6_stats.fib_route_nodes--; 1141 fn = fib6_repair_tree(fn); 1142 } 1143 1144 if (atomic_read(&rt->rt6i_ref) != 1) { 1145 /* This route is used as dummy address holder in some split 1146 * nodes. It is not leaked, but it still holds other resources, 1147 * which must be released in time. So, scan ascendant nodes 1148 * and replace dummy references to this route with references 1149 * to still alive ones. 1150 */ 1151 while (fn) { 1152 if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) { 1153 fn->leaf = fib6_find_prefix(fn); 1154 atomic_inc(&fn->leaf->rt6i_ref); 1155 rt6_release(rt); 1156 } 1157 fn = fn->parent; 1158 } 1159 /* No more references are possible at this point. */ 1160 if (atomic_read(&rt->rt6i_ref) != 1) BUG(); 1161 } 1162 1163 inet6_rt_notify(RTM_DELROUTE, rt, info); 1164 rt6_release(rt); 1165 } 1166 1167 int fib6_del(struct rt6_info *rt, struct nl_info *info) 1168 { 1169 struct fib6_node *fn = rt->rt6i_node; 1170 struct rt6_info **rtp; 1171 1172 #if RT6_DEBUG >= 2 1173 if (rt->u.dst.obsolete>0) { 1174 BUG_TRAP(fn==NULL); 1175 return -ENOENT; 1176 } 1177 #endif 1178 if (fn == NULL || rt == &ip6_null_entry) 1179 return -ENOENT; 1180 1181 BUG_TRAP(fn->fn_flags&RTN_RTINFO); 1182 1183 if (!(rt->rt6i_flags&RTF_CACHE)) { 1184 struct fib6_node *pn = fn; 1185 #ifdef CONFIG_IPV6_SUBTREES 1186 /* clones of this route might be in another subtree */ 1187 if (rt->rt6i_src.plen) { 1188 while (!(pn->fn_flags&RTN_ROOT)) 1189 pn = pn->parent; 1190 pn = pn->parent; 1191 } 1192 #endif 1193 fib6_prune_clones(pn, rt); 1194 } 1195 1196 /* 1197 * Walk the leaf entries looking for ourself 1198 */ 1199 1200 for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.dst.rt6_next) { 1201 if (*rtp == rt) { 1202 fib6_del_route(fn, rtp, info); 1203 return 0; 1204 } 1205 } 1206 return -ENOENT; 1207 } 1208 1209 /* 1210 * Tree traversal function. 1211 * 1212 * Certainly, it is not interrupt safe. 1213 * However, it is internally reenterable wrt itself and fib6_add/fib6_del. 1214 * It means, that we can modify tree during walking 1215 * and use this function for garbage collection, clone pruning, 1216 * cleaning tree when a device goes down etc. etc. 1217 * 1218 * It guarantees that every node will be traversed, 1219 * and that it will be traversed only once. 1220 * 1221 * Callback function w->func may return: 1222 * 0 -> continue walking. 1223 * positive value -> walking is suspended (used by tree dumps, 1224 * and probably by gc, if it will be split to several slices) 1225 * negative value -> terminate walking. 1226 * 1227 * The function itself returns: 1228 * 0 -> walk is complete. 1229 * >0 -> walk is incomplete (i.e. suspended) 1230 * <0 -> walk is terminated by an error. 1231 */ 1232 1233 static int fib6_walk_continue(struct fib6_walker_t *w) 1234 { 1235 struct fib6_node *fn, *pn; 1236 1237 for (;;) { 1238 fn = w->node; 1239 if (fn == NULL) 1240 return 0; 1241 1242 if (w->prune && fn != w->root && 1243 fn->fn_flags&RTN_RTINFO && w->state < FWS_C) { 1244 w->state = FWS_C; 1245 w->leaf = fn->leaf; 1246 } 1247 switch (w->state) { 1248 #ifdef CONFIG_IPV6_SUBTREES 1249 case FWS_S: 1250 if (FIB6_SUBTREE(fn)) { 1251 w->node = FIB6_SUBTREE(fn); 1252 continue; 1253 } 1254 w->state = FWS_L; 1255 #endif 1256 case FWS_L: 1257 if (fn->left) { 1258 w->node = fn->left; 1259 w->state = FWS_INIT; 1260 continue; 1261 } 1262 w->state = FWS_R; 1263 case FWS_R: 1264 if (fn->right) { 1265 w->node = fn->right; 1266 w->state = FWS_INIT; 1267 continue; 1268 } 1269 w->state = FWS_C; 1270 w->leaf = fn->leaf; 1271 case FWS_C: 1272 if (w->leaf && fn->fn_flags&RTN_RTINFO) { 1273 int err = w->func(w); 1274 if (err) 1275 return err; 1276 continue; 1277 } 1278 w->state = FWS_U; 1279 case FWS_U: 1280 if (fn == w->root) 1281 return 0; 1282 pn = fn->parent; 1283 w->node = pn; 1284 #ifdef CONFIG_IPV6_SUBTREES 1285 if (FIB6_SUBTREE(pn) == fn) { 1286 BUG_TRAP(fn->fn_flags&RTN_ROOT); 1287 w->state = FWS_L; 1288 continue; 1289 } 1290 #endif 1291 if (pn->left == fn) { 1292 w->state = FWS_R; 1293 continue; 1294 } 1295 if (pn->right == fn) { 1296 w->state = FWS_C; 1297 w->leaf = w->node->leaf; 1298 continue; 1299 } 1300 #if RT6_DEBUG >= 2 1301 BUG_TRAP(0); 1302 #endif 1303 } 1304 } 1305 } 1306 1307 static int fib6_walk(struct fib6_walker_t *w) 1308 { 1309 int res; 1310 1311 w->state = FWS_INIT; 1312 w->node = w->root; 1313 1314 fib6_walker_link(w); 1315 res = fib6_walk_continue(w); 1316 if (res <= 0) 1317 fib6_walker_unlink(w); 1318 return res; 1319 } 1320 1321 static int fib6_clean_node(struct fib6_walker_t *w) 1322 { 1323 int res; 1324 struct rt6_info *rt; 1325 struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w; 1326 1327 for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) { 1328 res = c->func(rt, c->arg); 1329 if (res < 0) { 1330 w->leaf = rt; 1331 res = fib6_del(rt, NULL); 1332 if (res) { 1333 #if RT6_DEBUG >= 2 1334 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res); 1335 #endif 1336 continue; 1337 } 1338 return 0; 1339 } 1340 BUG_TRAP(res==0); 1341 } 1342 w->leaf = rt; 1343 return 0; 1344 } 1345 1346 /* 1347 * Convenient frontend to tree walker. 1348 * 1349 * func is called on each route. 1350 * It may return -1 -> delete this route. 1351 * 0 -> continue walking 1352 * 1353 * prune==1 -> only immediate children of node (certainly, 1354 * ignoring pure split nodes) will be scanned. 1355 */ 1356 1357 static void fib6_clean_tree(struct fib6_node *root, 1358 int (*func)(struct rt6_info *, void *arg), 1359 int prune, void *arg) 1360 { 1361 struct fib6_cleaner_t c; 1362 1363 c.w.root = root; 1364 c.w.func = fib6_clean_node; 1365 c.w.prune = prune; 1366 c.func = func; 1367 c.arg = arg; 1368 1369 fib6_walk(&c.w); 1370 } 1371 1372 void fib6_clean_all(int (*func)(struct rt6_info *, void *arg), 1373 int prune, void *arg) 1374 { 1375 struct fib6_table *table; 1376 struct hlist_node *node; 1377 unsigned int h; 1378 1379 rcu_read_lock(); 1380 for (h = 0; h < FIB_TABLE_HASHSZ; h++) { 1381 hlist_for_each_entry_rcu(table, node, &fib_table_hash[h], 1382 tb6_hlist) { 1383 write_lock_bh(&table->tb6_lock); 1384 fib6_clean_tree(&table->tb6_root, func, prune, arg); 1385 write_unlock_bh(&table->tb6_lock); 1386 } 1387 } 1388 rcu_read_unlock(); 1389 } 1390 1391 static int fib6_prune_clone(struct rt6_info *rt, void *arg) 1392 { 1393 if (rt->rt6i_flags & RTF_CACHE) { 1394 RT6_TRACE("pruning clone %p\n", rt); 1395 return -1; 1396 } 1397 1398 return 0; 1399 } 1400 1401 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt) 1402 { 1403 fib6_clean_tree(fn, fib6_prune_clone, 1, rt); 1404 } 1405 1406 /* 1407 * Garbage collection 1408 */ 1409 1410 static struct fib6_gc_args 1411 { 1412 int timeout; 1413 int more; 1414 } gc_args; 1415 1416 static int fib6_age(struct rt6_info *rt, void *arg) 1417 { 1418 unsigned long now = jiffies; 1419 1420 /* 1421 * check addrconf expiration here. 1422 * Routes are expired even if they are in use. 1423 * 1424 * Also age clones. Note, that clones are aged out 1425 * only if they are not in use now. 1426 */ 1427 1428 if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) { 1429 if (time_after(now, rt->rt6i_expires)) { 1430 RT6_TRACE("expiring %p\n", rt); 1431 return -1; 1432 } 1433 gc_args.more++; 1434 } else if (rt->rt6i_flags & RTF_CACHE) { 1435 if (atomic_read(&rt->u.dst.__refcnt) == 0 && 1436 time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) { 1437 RT6_TRACE("aging clone %p\n", rt); 1438 return -1; 1439 } else if ((rt->rt6i_flags & RTF_GATEWAY) && 1440 (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) { 1441 RT6_TRACE("purging route %p via non-router but gateway\n", 1442 rt); 1443 return -1; 1444 } 1445 gc_args.more++; 1446 } 1447 1448 return 0; 1449 } 1450 1451 static DEFINE_SPINLOCK(fib6_gc_lock); 1452 1453 void fib6_run_gc(unsigned long dummy) 1454 { 1455 if (dummy != ~0UL) { 1456 spin_lock_bh(&fib6_gc_lock); 1457 gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval; 1458 } else { 1459 local_bh_disable(); 1460 if (!spin_trylock(&fib6_gc_lock)) { 1461 mod_timer(&ip6_fib_timer, jiffies + HZ); 1462 local_bh_enable(); 1463 return; 1464 } 1465 gc_args.timeout = ip6_rt_gc_interval; 1466 } 1467 gc_args.more = 0; 1468 1469 ndisc_dst_gc(&gc_args.more); 1470 fib6_clean_all(fib6_age, 0, NULL); 1471 1472 if (gc_args.more) 1473 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval); 1474 else { 1475 del_timer(&ip6_fib_timer); 1476 ip6_fib_timer.expires = 0; 1477 } 1478 spin_unlock_bh(&fib6_gc_lock); 1479 } 1480 1481 void __init fib6_init(void) 1482 { 1483 fib6_node_kmem = kmem_cache_create("fib6_nodes", 1484 sizeof(struct fib6_node), 1485 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, 1486 NULL, NULL); 1487 1488 fib6_tables_init(); 1489 1490 __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib); 1491 } 1492 1493 void fib6_gc_cleanup(void) 1494 { 1495 del_timer(&ip6_fib_timer); 1496 kmem_cache_destroy(fib6_node_kmem); 1497 } 1498