1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux INET6 implementation 4 * Forwarding Information Database 5 * 6 * Authors: 7 * Pedro Roque <roque@di.fc.ul.pt> 8 * 9 * Changes: 10 * Yuji SEKIYA @USAGI: Support default route on router node; 11 * remove ip6_null_entry from the top of 12 * routing table. 13 * Ville Nuorvala: Fixed routing subtrees. 14 */ 15 16 #define pr_fmt(fmt) "IPv6: " fmt 17 18 #include <linux/bpf.h> 19 #include <linux/errno.h> 20 #include <linux/types.h> 21 #include <linux/net.h> 22 #include <linux/route.h> 23 #include <linux/netdevice.h> 24 #include <linux/in6.h> 25 #include <linux/init.h> 26 #include <linux/list.h> 27 #include <linux/slab.h> 28 29 #include <net/ip.h> 30 #include <net/ipv6.h> 31 #include <net/ndisc.h> 32 #include <net/addrconf.h> 33 #include <net/lwtunnel.h> 34 #include <net/fib_notifier.h> 35 36 #include <net/ip_fib.h> 37 #include <net/ip6_fib.h> 38 #include <net/ip6_route.h> 39 40 static struct kmem_cache *fib6_node_kmem __read_mostly; 41 42 struct fib6_cleaner { 43 struct fib6_walker w; 44 struct net *net; 45 int (*func)(struct fib6_info *, void *arg); 46 int sernum; 47 void *arg; 48 bool skip_notify; 49 }; 50 51 #ifdef CONFIG_IPV6_SUBTREES 52 #define FWS_INIT FWS_S 53 #else 54 #define FWS_INIT FWS_L 55 #endif 56 57 static struct fib6_info *fib6_find_prefix(struct net *net, 58 struct fib6_table *table, 59 struct fib6_node *fn); 60 static struct fib6_node *fib6_repair_tree(struct net *net, 61 struct fib6_table *table, 62 struct fib6_node *fn); 63 static int fib6_walk(struct net *net, struct fib6_walker *w); 64 static int fib6_walk_continue(struct fib6_walker *w); 65 66 /* 67 * A routing update causes an increase of the serial number on the 68 * affected subtree. This allows for cached routes to be asynchronously 69 * tested when modifications are made to the destination cache as a 70 * result of redirects, path MTU changes, etc. 71 */ 72 73 static void fib6_gc_timer_cb(struct timer_list *t); 74 75 #define FOR_WALKERS(net, w) \ 76 list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh) 77 78 static void fib6_walker_link(struct net *net, struct fib6_walker *w) 79 { 80 write_lock_bh(&net->ipv6.fib6_walker_lock); 81 list_add(&w->lh, &net->ipv6.fib6_walkers); 82 write_unlock_bh(&net->ipv6.fib6_walker_lock); 83 } 84 85 static void fib6_walker_unlink(struct net *net, struct fib6_walker *w) 86 { 87 write_lock_bh(&net->ipv6.fib6_walker_lock); 88 list_del(&w->lh); 89 write_unlock_bh(&net->ipv6.fib6_walker_lock); 90 } 91 92 static int fib6_new_sernum(struct net *net) 93 { 94 int new, old = atomic_read(&net->ipv6.fib6_sernum); 95 96 do { 97 new = old < INT_MAX ? old + 1 : 1; 98 } while (!atomic_try_cmpxchg(&net->ipv6.fib6_sernum, &old, new)); 99 100 return new; 101 } 102 103 enum { 104 FIB6_NO_SERNUM_CHANGE = 0, 105 }; 106 107 void fib6_update_sernum(struct net *net, struct fib6_info *f6i) 108 { 109 struct fib6_node *fn; 110 111 fn = rcu_dereference_protected(f6i->fib6_node, 112 lockdep_is_held(&f6i->fib6_table->tb6_lock)); 113 if (fn) 114 WRITE_ONCE(fn->fn_sernum, fib6_new_sernum(net)); 115 } 116 117 /* 118 * Auxiliary address test functions for the radix tree. 119 * 120 * These assume a 32bit processor (although it will work on 121 * 64bit processors) 122 */ 123 124 /* 125 * test bit 126 */ 127 #if defined(__LITTLE_ENDIAN) 128 # define BITOP_BE32_SWIZZLE (0x1F & ~7) 129 #else 130 # define BITOP_BE32_SWIZZLE 0 131 #endif 132 133 static __be32 addr_bit_set(const void *token, int fn_bit) 134 { 135 const __be32 *addr = token; 136 /* 137 * Here, 138 * 1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f) 139 * is optimized version of 140 * htonl(1 << ((~fn_bit)&0x1F)) 141 * See include/asm-generic/bitops/le.h. 142 */ 143 return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) & 144 addr[fn_bit >> 5]; 145 } 146 147 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh) 148 { 149 struct fib6_info *f6i; 150 size_t sz = sizeof(*f6i); 151 152 if (with_fib6_nh) 153 sz += sizeof(struct fib6_nh); 154 155 f6i = kzalloc(sz, gfp_flags); 156 if (!f6i) 157 return NULL; 158 159 /* fib6_siblings is a union with nh_list, so this initializes both */ 160 INIT_LIST_HEAD(&f6i->fib6_siblings); 161 refcount_set(&f6i->fib6_ref, 1); 162 163 return f6i; 164 } 165 166 void fib6_info_destroy_rcu(struct rcu_head *head) 167 { 168 struct fib6_info *f6i = container_of(head, struct fib6_info, rcu); 169 170 WARN_ON(f6i->fib6_node); 171 172 if (f6i->nh) 173 nexthop_put(f6i->nh); 174 else 175 fib6_nh_release(f6i->fib6_nh); 176 177 ip_fib_metrics_put(f6i->fib6_metrics); 178 kfree(f6i); 179 } 180 EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu); 181 182 static struct fib6_node *node_alloc(struct net *net) 183 { 184 struct fib6_node *fn; 185 186 fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC); 187 if (fn) 188 net->ipv6.rt6_stats->fib_nodes++; 189 190 return fn; 191 } 192 193 static void node_free_immediate(struct net *net, struct fib6_node *fn) 194 { 195 kmem_cache_free(fib6_node_kmem, fn); 196 net->ipv6.rt6_stats->fib_nodes--; 197 } 198 199 static void node_free_rcu(struct rcu_head *head) 200 { 201 struct fib6_node *fn = container_of(head, struct fib6_node, rcu); 202 203 kmem_cache_free(fib6_node_kmem, fn); 204 } 205 206 static void node_free(struct net *net, struct fib6_node *fn) 207 { 208 call_rcu(&fn->rcu, node_free_rcu); 209 net->ipv6.rt6_stats->fib_nodes--; 210 } 211 212 static void fib6_free_table(struct fib6_table *table) 213 { 214 inetpeer_invalidate_tree(&table->tb6_peers); 215 kfree(table); 216 } 217 218 static void fib6_link_table(struct net *net, struct fib6_table *tb) 219 { 220 unsigned int h; 221 222 /* 223 * Initialize table lock at a single place to give lockdep a key, 224 * tables aren't visible prior to being linked to the list. 225 */ 226 spin_lock_init(&tb->tb6_lock); 227 h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1); 228 229 /* 230 * No protection necessary, this is the only list mutatation 231 * operation, tables never disappear once they exist. 232 */ 233 hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]); 234 } 235 236 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 237 238 static struct fib6_table *fib6_alloc_table(struct net *net, u32 id) 239 { 240 struct fib6_table *table; 241 242 table = kzalloc(sizeof(*table), GFP_ATOMIC); 243 if (table) { 244 table->tb6_id = id; 245 rcu_assign_pointer(table->tb6_root.leaf, 246 net->ipv6.fib6_null_entry); 247 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO; 248 inet_peer_base_init(&table->tb6_peers); 249 } 250 251 return table; 252 } 253 254 struct fib6_table *fib6_new_table(struct net *net, u32 id) 255 { 256 struct fib6_table *tb; 257 258 if (id == 0) 259 id = RT6_TABLE_MAIN; 260 tb = fib6_get_table(net, id); 261 if (tb) 262 return tb; 263 264 tb = fib6_alloc_table(net, id); 265 if (tb) 266 fib6_link_table(net, tb); 267 268 return tb; 269 } 270 EXPORT_SYMBOL_GPL(fib6_new_table); 271 272 struct fib6_table *fib6_get_table(struct net *net, u32 id) 273 { 274 struct fib6_table *tb; 275 struct hlist_head *head; 276 unsigned int h; 277 278 if (id == 0) 279 id = RT6_TABLE_MAIN; 280 h = id & (FIB6_TABLE_HASHSZ - 1); 281 rcu_read_lock(); 282 head = &net->ipv6.fib_table_hash[h]; 283 hlist_for_each_entry_rcu(tb, head, tb6_hlist) { 284 if (tb->tb6_id == id) { 285 rcu_read_unlock(); 286 return tb; 287 } 288 } 289 rcu_read_unlock(); 290 291 return NULL; 292 } 293 EXPORT_SYMBOL_GPL(fib6_get_table); 294 295 static void __net_init fib6_tables_init(struct net *net) 296 { 297 fib6_link_table(net, net->ipv6.fib6_main_tbl); 298 fib6_link_table(net, net->ipv6.fib6_local_tbl); 299 } 300 #else 301 302 struct fib6_table *fib6_new_table(struct net *net, u32 id) 303 { 304 return fib6_get_table(net, id); 305 } 306 307 struct fib6_table *fib6_get_table(struct net *net, u32 id) 308 { 309 return net->ipv6.fib6_main_tbl; 310 } 311 312 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 313 const struct sk_buff *skb, 314 int flags, pol_lookup_t lookup) 315 { 316 struct rt6_info *rt; 317 318 rt = pol_lookup_func(lookup, 319 net, net->ipv6.fib6_main_tbl, fl6, skb, flags); 320 if (rt->dst.error == -EAGAIN) { 321 ip6_rt_put_flags(rt, flags); 322 rt = net->ipv6.ip6_null_entry; 323 if (!(flags & RT6_LOOKUP_F_DST_NOREF)) 324 dst_hold(&rt->dst); 325 } 326 327 return &rt->dst; 328 } 329 330 /* called with rcu lock held; no reference taken on fib6_info */ 331 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 332 struct fib6_result *res, int flags) 333 { 334 return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6, 335 res, flags); 336 } 337 338 static void __net_init fib6_tables_init(struct net *net) 339 { 340 fib6_link_table(net, net->ipv6.fib6_main_tbl); 341 } 342 343 #endif 344 345 unsigned int fib6_tables_seq_read(struct net *net) 346 { 347 unsigned int h, fib_seq = 0; 348 349 rcu_read_lock(); 350 for (h = 0; h < FIB6_TABLE_HASHSZ; h++) { 351 struct hlist_head *head = &net->ipv6.fib_table_hash[h]; 352 struct fib6_table *tb; 353 354 hlist_for_each_entry_rcu(tb, head, tb6_hlist) 355 fib_seq += tb->fib_seq; 356 } 357 rcu_read_unlock(); 358 359 return fib_seq; 360 } 361 362 static int call_fib6_entry_notifier(struct notifier_block *nb, 363 enum fib_event_type event_type, 364 struct fib6_info *rt, 365 struct netlink_ext_ack *extack) 366 { 367 struct fib6_entry_notifier_info info = { 368 .info.extack = extack, 369 .rt = rt, 370 }; 371 372 return call_fib6_notifier(nb, event_type, &info.info); 373 } 374 375 static int call_fib6_multipath_entry_notifier(struct notifier_block *nb, 376 enum fib_event_type event_type, 377 struct fib6_info *rt, 378 unsigned int nsiblings, 379 struct netlink_ext_ack *extack) 380 { 381 struct fib6_entry_notifier_info info = { 382 .info.extack = extack, 383 .rt = rt, 384 .nsiblings = nsiblings, 385 }; 386 387 return call_fib6_notifier(nb, event_type, &info.info); 388 } 389 390 int call_fib6_entry_notifiers(struct net *net, 391 enum fib_event_type event_type, 392 struct fib6_info *rt, 393 struct netlink_ext_ack *extack) 394 { 395 struct fib6_entry_notifier_info info = { 396 .info.extack = extack, 397 .rt = rt, 398 }; 399 400 rt->fib6_table->fib_seq++; 401 return call_fib6_notifiers(net, event_type, &info.info); 402 } 403 404 int call_fib6_multipath_entry_notifiers(struct net *net, 405 enum fib_event_type event_type, 406 struct fib6_info *rt, 407 unsigned int nsiblings, 408 struct netlink_ext_ack *extack) 409 { 410 struct fib6_entry_notifier_info info = { 411 .info.extack = extack, 412 .rt = rt, 413 .nsiblings = nsiblings, 414 }; 415 416 rt->fib6_table->fib_seq++; 417 return call_fib6_notifiers(net, event_type, &info.info); 418 } 419 420 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt) 421 { 422 struct fib6_entry_notifier_info info = { 423 .rt = rt, 424 .nsiblings = rt->fib6_nsiblings, 425 }; 426 427 rt->fib6_table->fib_seq++; 428 return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info); 429 } 430 431 struct fib6_dump_arg { 432 struct net *net; 433 struct notifier_block *nb; 434 struct netlink_ext_ack *extack; 435 }; 436 437 static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg) 438 { 439 enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE; 440 int err; 441 442 if (!rt || rt == arg->net->ipv6.fib6_null_entry) 443 return 0; 444 445 if (rt->fib6_nsiblings) 446 err = call_fib6_multipath_entry_notifier(arg->nb, fib_event, 447 rt, 448 rt->fib6_nsiblings, 449 arg->extack); 450 else 451 err = call_fib6_entry_notifier(arg->nb, fib_event, rt, 452 arg->extack); 453 454 return err; 455 } 456 457 static int fib6_node_dump(struct fib6_walker *w) 458 { 459 int err; 460 461 err = fib6_rt_dump(w->leaf, w->args); 462 w->leaf = NULL; 463 return err; 464 } 465 466 static int fib6_table_dump(struct net *net, struct fib6_table *tb, 467 struct fib6_walker *w) 468 { 469 int err; 470 471 w->root = &tb->tb6_root; 472 spin_lock_bh(&tb->tb6_lock); 473 err = fib6_walk(net, w); 474 spin_unlock_bh(&tb->tb6_lock); 475 return err; 476 } 477 478 /* Called with rcu_read_lock() */ 479 int fib6_tables_dump(struct net *net, struct notifier_block *nb, 480 struct netlink_ext_ack *extack) 481 { 482 struct fib6_dump_arg arg; 483 struct fib6_walker *w; 484 unsigned int h; 485 int err = 0; 486 487 w = kzalloc(sizeof(*w), GFP_ATOMIC); 488 if (!w) 489 return -ENOMEM; 490 491 w->func = fib6_node_dump; 492 arg.net = net; 493 arg.nb = nb; 494 arg.extack = extack; 495 w->args = &arg; 496 497 for (h = 0; h < FIB6_TABLE_HASHSZ; h++) { 498 struct hlist_head *head = &net->ipv6.fib_table_hash[h]; 499 struct fib6_table *tb; 500 501 hlist_for_each_entry_rcu(tb, head, tb6_hlist) { 502 err = fib6_table_dump(net, tb, w); 503 if (err) 504 goto out; 505 } 506 } 507 508 out: 509 kfree(w); 510 511 /* The tree traversal function should never return a positive value. */ 512 return err > 0 ? -EINVAL : err; 513 } 514 515 static int fib6_dump_node(struct fib6_walker *w) 516 { 517 int res; 518 struct fib6_info *rt; 519 520 for_each_fib6_walker_rt(w) { 521 res = rt6_dump_route(rt, w->args, w->skip_in_node); 522 if (res >= 0) { 523 /* Frame is full, suspend walking */ 524 w->leaf = rt; 525 526 /* We'll restart from this node, so if some routes were 527 * already dumped, skip them next time. 528 */ 529 w->skip_in_node += res; 530 531 return 1; 532 } 533 w->skip_in_node = 0; 534 535 /* Multipath routes are dumped in one route with the 536 * RTA_MULTIPATH attribute. Jump 'rt' to point to the 537 * last sibling of this route (no need to dump the 538 * sibling routes again) 539 */ 540 if (rt->fib6_nsiblings) 541 rt = list_last_entry(&rt->fib6_siblings, 542 struct fib6_info, 543 fib6_siblings); 544 } 545 w->leaf = NULL; 546 return 0; 547 } 548 549 static void fib6_dump_end(struct netlink_callback *cb) 550 { 551 struct net *net = sock_net(cb->skb->sk); 552 struct fib6_walker *w = (void *)cb->args[2]; 553 554 if (w) { 555 if (cb->args[4]) { 556 cb->args[4] = 0; 557 fib6_walker_unlink(net, w); 558 } 559 cb->args[2] = 0; 560 kfree(w); 561 } 562 cb->done = (void *)cb->args[3]; 563 cb->args[1] = 3; 564 } 565 566 static int fib6_dump_done(struct netlink_callback *cb) 567 { 568 fib6_dump_end(cb); 569 return cb->done ? cb->done(cb) : 0; 570 } 571 572 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb, 573 struct netlink_callback *cb) 574 { 575 struct net *net = sock_net(skb->sk); 576 struct fib6_walker *w; 577 int res; 578 579 w = (void *)cb->args[2]; 580 w->root = &table->tb6_root; 581 582 if (cb->args[4] == 0) { 583 w->count = 0; 584 w->skip = 0; 585 w->skip_in_node = 0; 586 587 spin_lock_bh(&table->tb6_lock); 588 res = fib6_walk(net, w); 589 spin_unlock_bh(&table->tb6_lock); 590 if (res > 0) { 591 cb->args[4] = 1; 592 cb->args[5] = READ_ONCE(w->root->fn_sernum); 593 } 594 } else { 595 int sernum = READ_ONCE(w->root->fn_sernum); 596 if (cb->args[5] != sernum) { 597 /* Begin at the root if the tree changed */ 598 cb->args[5] = sernum; 599 w->state = FWS_INIT; 600 w->node = w->root; 601 w->skip = w->count; 602 w->skip_in_node = 0; 603 } else 604 w->skip = 0; 605 606 spin_lock_bh(&table->tb6_lock); 607 res = fib6_walk_continue(w); 608 spin_unlock_bh(&table->tb6_lock); 609 if (res <= 0) { 610 fib6_walker_unlink(net, w); 611 cb->args[4] = 0; 612 } 613 } 614 615 return res; 616 } 617 618 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) 619 { 620 struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true, 621 .filter.dump_routes = true }; 622 const struct nlmsghdr *nlh = cb->nlh; 623 struct net *net = sock_net(skb->sk); 624 unsigned int h, s_h; 625 unsigned int e = 0, s_e; 626 struct fib6_walker *w; 627 struct fib6_table *tb; 628 struct hlist_head *head; 629 int res = 0; 630 631 if (cb->strict_check) { 632 int err; 633 634 err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb); 635 if (err < 0) 636 return err; 637 } else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) { 638 struct rtmsg *rtm = nlmsg_data(nlh); 639 640 if (rtm->rtm_flags & RTM_F_PREFIX) 641 arg.filter.flags = RTM_F_PREFIX; 642 } 643 644 w = (void *)cb->args[2]; 645 if (!w) { 646 /* New dump: 647 * 648 * 1. allocate and initialize walker. 649 */ 650 w = kzalloc(sizeof(*w), GFP_ATOMIC); 651 if (!w) 652 return -ENOMEM; 653 w->func = fib6_dump_node; 654 cb->args[2] = (long)w; 655 656 /* 2. hook callback destructor. 657 */ 658 cb->args[3] = (long)cb->done; 659 cb->done = fib6_dump_done; 660 661 } 662 663 arg.skb = skb; 664 arg.cb = cb; 665 arg.net = net; 666 w->args = &arg; 667 668 if (arg.filter.table_id) { 669 tb = fib6_get_table(net, arg.filter.table_id); 670 if (!tb) { 671 if (rtnl_msg_family(cb->nlh) != PF_INET6) 672 goto out; 673 674 NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist"); 675 return -ENOENT; 676 } 677 678 if (!cb->args[0]) { 679 res = fib6_dump_table(tb, skb, cb); 680 if (!res) 681 cb->args[0] = 1; 682 } 683 goto out; 684 } 685 686 s_h = cb->args[0]; 687 s_e = cb->args[1]; 688 689 rcu_read_lock(); 690 for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) { 691 e = 0; 692 head = &net->ipv6.fib_table_hash[h]; 693 hlist_for_each_entry_rcu(tb, head, tb6_hlist) { 694 if (e < s_e) 695 goto next; 696 res = fib6_dump_table(tb, skb, cb); 697 if (res != 0) 698 goto out_unlock; 699 next: 700 e++; 701 } 702 } 703 out_unlock: 704 rcu_read_unlock(); 705 cb->args[1] = e; 706 cb->args[0] = h; 707 out: 708 res = res < 0 ? res : skb->len; 709 if (res <= 0) 710 fib6_dump_end(cb); 711 return res; 712 } 713 714 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val) 715 { 716 if (!f6i) 717 return; 718 719 if (f6i->fib6_metrics == &dst_default_metrics) { 720 struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC); 721 722 if (!p) 723 return; 724 725 refcount_set(&p->refcnt, 1); 726 f6i->fib6_metrics = p; 727 } 728 729 f6i->fib6_metrics->metrics[metric - 1] = val; 730 } 731 732 /* 733 * Routing Table 734 * 735 * return the appropriate node for a routing tree "add" operation 736 * by either creating and inserting or by returning an existing 737 * node. 738 */ 739 740 static struct fib6_node *fib6_add_1(struct net *net, 741 struct fib6_table *table, 742 struct fib6_node *root, 743 struct in6_addr *addr, int plen, 744 int offset, int allow_create, 745 int replace_required, 746 struct netlink_ext_ack *extack) 747 { 748 struct fib6_node *fn, *in, *ln; 749 struct fib6_node *pn = NULL; 750 struct rt6key *key; 751 int bit; 752 __be32 dir = 0; 753 754 RT6_TRACE("fib6_add_1\n"); 755 756 /* insert node in tree */ 757 758 fn = root; 759 760 do { 761 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf, 762 lockdep_is_held(&table->tb6_lock)); 763 key = (struct rt6key *)((u8 *)leaf + offset); 764 765 /* 766 * Prefix match 767 */ 768 if (plen < fn->fn_bit || 769 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) { 770 if (!allow_create) { 771 if (replace_required) { 772 NL_SET_ERR_MSG(extack, 773 "Can not replace route - no match found"); 774 pr_warn("Can't replace route, no match found\n"); 775 return ERR_PTR(-ENOENT); 776 } 777 pr_warn("NLM_F_CREATE should be set when creating new route\n"); 778 } 779 goto insert_above; 780 } 781 782 /* 783 * Exact match ? 784 */ 785 786 if (plen == fn->fn_bit) { 787 /* clean up an intermediate node */ 788 if (!(fn->fn_flags & RTN_RTINFO)) { 789 RCU_INIT_POINTER(fn->leaf, NULL); 790 fib6_info_release(leaf); 791 /* remove null_entry in the root node */ 792 } else if (fn->fn_flags & RTN_TL_ROOT && 793 rcu_access_pointer(fn->leaf) == 794 net->ipv6.fib6_null_entry) { 795 RCU_INIT_POINTER(fn->leaf, NULL); 796 } 797 798 return fn; 799 } 800 801 /* 802 * We have more bits to go 803 */ 804 805 /* Try to walk down on tree. */ 806 dir = addr_bit_set(addr, fn->fn_bit); 807 pn = fn; 808 fn = dir ? 809 rcu_dereference_protected(fn->right, 810 lockdep_is_held(&table->tb6_lock)) : 811 rcu_dereference_protected(fn->left, 812 lockdep_is_held(&table->tb6_lock)); 813 } while (fn); 814 815 if (!allow_create) { 816 /* We should not create new node because 817 * NLM_F_REPLACE was specified without NLM_F_CREATE 818 * I assume it is safe to require NLM_F_CREATE when 819 * REPLACE flag is used! Later we may want to remove the 820 * check for replace_required, because according 821 * to netlink specification, NLM_F_CREATE 822 * MUST be specified if new route is created. 823 * That would keep IPv6 consistent with IPv4 824 */ 825 if (replace_required) { 826 NL_SET_ERR_MSG(extack, 827 "Can not replace route - no match found"); 828 pr_warn("Can't replace route, no match found\n"); 829 return ERR_PTR(-ENOENT); 830 } 831 pr_warn("NLM_F_CREATE should be set when creating new route\n"); 832 } 833 /* 834 * We walked to the bottom of tree. 835 * Create new leaf node without children. 836 */ 837 838 ln = node_alloc(net); 839 840 if (!ln) 841 return ERR_PTR(-ENOMEM); 842 ln->fn_bit = plen; 843 RCU_INIT_POINTER(ln->parent, pn); 844 845 if (dir) 846 rcu_assign_pointer(pn->right, ln); 847 else 848 rcu_assign_pointer(pn->left, ln); 849 850 return ln; 851 852 853 insert_above: 854 /* 855 * split since we don't have a common prefix anymore or 856 * we have a less significant route. 857 * we've to insert an intermediate node on the list 858 * this new node will point to the one we need to create 859 * and the current 860 */ 861 862 pn = rcu_dereference_protected(fn->parent, 863 lockdep_is_held(&table->tb6_lock)); 864 865 /* find 1st bit in difference between the 2 addrs. 866 867 See comment in __ipv6_addr_diff: bit may be an invalid value, 868 but if it is >= plen, the value is ignored in any case. 869 */ 870 871 bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr)); 872 873 /* 874 * (intermediate)[in] 875 * / \ 876 * (new leaf node)[ln] (old node)[fn] 877 */ 878 if (plen > bit) { 879 in = node_alloc(net); 880 ln = node_alloc(net); 881 882 if (!in || !ln) { 883 if (in) 884 node_free_immediate(net, in); 885 if (ln) 886 node_free_immediate(net, ln); 887 return ERR_PTR(-ENOMEM); 888 } 889 890 /* 891 * new intermediate node. 892 * RTN_RTINFO will 893 * be off since that an address that chooses one of 894 * the branches would not match less specific routes 895 * in the other branch 896 */ 897 898 in->fn_bit = bit; 899 900 RCU_INIT_POINTER(in->parent, pn); 901 in->leaf = fn->leaf; 902 fib6_info_hold(rcu_dereference_protected(in->leaf, 903 lockdep_is_held(&table->tb6_lock))); 904 905 /* update parent pointer */ 906 if (dir) 907 rcu_assign_pointer(pn->right, in); 908 else 909 rcu_assign_pointer(pn->left, in); 910 911 ln->fn_bit = plen; 912 913 RCU_INIT_POINTER(ln->parent, in); 914 rcu_assign_pointer(fn->parent, in); 915 916 if (addr_bit_set(addr, bit)) { 917 rcu_assign_pointer(in->right, ln); 918 rcu_assign_pointer(in->left, fn); 919 } else { 920 rcu_assign_pointer(in->left, ln); 921 rcu_assign_pointer(in->right, fn); 922 } 923 } else { /* plen <= bit */ 924 925 /* 926 * (new leaf node)[ln] 927 * / \ 928 * (old node)[fn] NULL 929 */ 930 931 ln = node_alloc(net); 932 933 if (!ln) 934 return ERR_PTR(-ENOMEM); 935 936 ln->fn_bit = plen; 937 938 RCU_INIT_POINTER(ln->parent, pn); 939 940 if (addr_bit_set(&key->addr, plen)) 941 RCU_INIT_POINTER(ln->right, fn); 942 else 943 RCU_INIT_POINTER(ln->left, fn); 944 945 rcu_assign_pointer(fn->parent, ln); 946 947 if (dir) 948 rcu_assign_pointer(pn->right, ln); 949 else 950 rcu_assign_pointer(pn->left, ln); 951 } 952 return ln; 953 } 954 955 static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh, 956 const struct fib6_info *match, 957 const struct fib6_table *table) 958 { 959 int cpu; 960 961 if (!fib6_nh->rt6i_pcpu) 962 return; 963 964 /* release the reference to this fib entry from 965 * all of its cached pcpu routes 966 */ 967 for_each_possible_cpu(cpu) { 968 struct rt6_info **ppcpu_rt; 969 struct rt6_info *pcpu_rt; 970 971 ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu); 972 pcpu_rt = *ppcpu_rt; 973 974 /* only dropping the 'from' reference if the cached route 975 * is using 'match'. The cached pcpu_rt->from only changes 976 * from a fib6_info to NULL (ip6_dst_destroy); it can never 977 * change from one fib6_info reference to another 978 */ 979 if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) { 980 struct fib6_info *from; 981 982 from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL); 983 fib6_info_release(from); 984 } 985 } 986 } 987 988 struct fib6_nh_pcpu_arg { 989 struct fib6_info *from; 990 const struct fib6_table *table; 991 }; 992 993 static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg) 994 { 995 struct fib6_nh_pcpu_arg *arg = _arg; 996 997 __fib6_drop_pcpu_from(nh, arg->from, arg->table); 998 return 0; 999 } 1000 1001 static void fib6_drop_pcpu_from(struct fib6_info *f6i, 1002 const struct fib6_table *table) 1003 { 1004 /* Make sure rt6_make_pcpu_route() wont add other percpu routes 1005 * while we are cleaning them here. 1006 */ 1007 f6i->fib6_destroying = 1; 1008 mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */ 1009 1010 if (f6i->nh) { 1011 struct fib6_nh_pcpu_arg arg = { 1012 .from = f6i, 1013 .table = table 1014 }; 1015 1016 nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from, 1017 &arg); 1018 } else { 1019 struct fib6_nh *fib6_nh; 1020 1021 fib6_nh = f6i->fib6_nh; 1022 __fib6_drop_pcpu_from(fib6_nh, f6i, table); 1023 } 1024 } 1025 1026 static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn, 1027 struct net *net) 1028 { 1029 struct fib6_table *table = rt->fib6_table; 1030 1031 /* Flush all cached dst in exception table */ 1032 rt6_flush_exceptions(rt); 1033 fib6_drop_pcpu_from(rt, table); 1034 1035 if (rt->nh && !list_empty(&rt->nh_list)) 1036 list_del_init(&rt->nh_list); 1037 1038 if (refcount_read(&rt->fib6_ref) != 1) { 1039 /* This route is used as dummy address holder in some split 1040 * nodes. It is not leaked, but it still holds other resources, 1041 * which must be released in time. So, scan ascendant nodes 1042 * and replace dummy references to this route with references 1043 * to still alive ones. 1044 */ 1045 while (fn) { 1046 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf, 1047 lockdep_is_held(&table->tb6_lock)); 1048 struct fib6_info *new_leaf; 1049 if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) { 1050 new_leaf = fib6_find_prefix(net, table, fn); 1051 fib6_info_hold(new_leaf); 1052 1053 rcu_assign_pointer(fn->leaf, new_leaf); 1054 fib6_info_release(rt); 1055 } 1056 fn = rcu_dereference_protected(fn->parent, 1057 lockdep_is_held(&table->tb6_lock)); 1058 } 1059 } 1060 } 1061 1062 /* 1063 * Insert routing information in a node. 1064 */ 1065 1066 static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 1067 struct nl_info *info, 1068 struct netlink_ext_ack *extack) 1069 { 1070 struct fib6_info *leaf = rcu_dereference_protected(fn->leaf, 1071 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1072 struct fib6_info *iter = NULL; 1073 struct fib6_info __rcu **ins; 1074 struct fib6_info __rcu **fallback_ins = NULL; 1075 int replace = (info->nlh && 1076 (info->nlh->nlmsg_flags & NLM_F_REPLACE)); 1077 int add = (!info->nlh || 1078 (info->nlh->nlmsg_flags & NLM_F_CREATE)); 1079 int found = 0; 1080 bool rt_can_ecmp = rt6_qualify_for_ecmp(rt); 1081 bool notify_sibling_rt = false; 1082 u16 nlflags = NLM_F_EXCL; 1083 int err; 1084 1085 if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND)) 1086 nlflags |= NLM_F_APPEND; 1087 1088 ins = &fn->leaf; 1089 1090 for (iter = leaf; iter; 1091 iter = rcu_dereference_protected(iter->fib6_next, 1092 lockdep_is_held(&rt->fib6_table->tb6_lock))) { 1093 /* 1094 * Search for duplicates 1095 */ 1096 1097 if (iter->fib6_metric == rt->fib6_metric) { 1098 /* 1099 * Same priority level 1100 */ 1101 if (info->nlh && 1102 (info->nlh->nlmsg_flags & NLM_F_EXCL)) 1103 return -EEXIST; 1104 1105 nlflags &= ~NLM_F_EXCL; 1106 if (replace) { 1107 if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) { 1108 found++; 1109 break; 1110 } 1111 fallback_ins = fallback_ins ?: ins; 1112 goto next_iter; 1113 } 1114 1115 if (rt6_duplicate_nexthop(iter, rt)) { 1116 if (rt->fib6_nsiblings) 1117 rt->fib6_nsiblings = 0; 1118 if (!(iter->fib6_flags & RTF_EXPIRES)) 1119 return -EEXIST; 1120 if (!(rt->fib6_flags & RTF_EXPIRES)) 1121 fib6_clean_expires(iter); 1122 else 1123 fib6_set_expires(iter, rt->expires); 1124 1125 if (rt->fib6_pmtu) 1126 fib6_metric_set(iter, RTAX_MTU, 1127 rt->fib6_pmtu); 1128 return -EEXIST; 1129 } 1130 /* If we have the same destination and the same metric, 1131 * but not the same gateway, then the route we try to 1132 * add is sibling to this route, increment our counter 1133 * of siblings, and later we will add our route to the 1134 * list. 1135 * Only static routes (which don't have flag 1136 * RTF_EXPIRES) are used for ECMPv6. 1137 * 1138 * To avoid long list, we only had siblings if the 1139 * route have a gateway. 1140 */ 1141 if (rt_can_ecmp && 1142 rt6_qualify_for_ecmp(iter)) 1143 rt->fib6_nsiblings++; 1144 } 1145 1146 if (iter->fib6_metric > rt->fib6_metric) 1147 break; 1148 1149 next_iter: 1150 ins = &iter->fib6_next; 1151 } 1152 1153 if (fallback_ins && !found) { 1154 /* No matching route with same ecmp-able-ness found, replace 1155 * first matching route 1156 */ 1157 ins = fallback_ins; 1158 iter = rcu_dereference_protected(*ins, 1159 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1160 found++; 1161 } 1162 1163 /* Reset round-robin state, if necessary */ 1164 if (ins == &fn->leaf) 1165 fn->rr_ptr = NULL; 1166 1167 /* Link this route to others same route. */ 1168 if (rt->fib6_nsiblings) { 1169 unsigned int fib6_nsiblings; 1170 struct fib6_info *sibling, *temp_sibling; 1171 1172 /* Find the first route that have the same metric */ 1173 sibling = leaf; 1174 notify_sibling_rt = true; 1175 while (sibling) { 1176 if (sibling->fib6_metric == rt->fib6_metric && 1177 rt6_qualify_for_ecmp(sibling)) { 1178 list_add_tail(&rt->fib6_siblings, 1179 &sibling->fib6_siblings); 1180 break; 1181 } 1182 sibling = rcu_dereference_protected(sibling->fib6_next, 1183 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1184 notify_sibling_rt = false; 1185 } 1186 /* For each sibling in the list, increment the counter of 1187 * siblings. BUG() if counters does not match, list of siblings 1188 * is broken! 1189 */ 1190 fib6_nsiblings = 0; 1191 list_for_each_entry_safe(sibling, temp_sibling, 1192 &rt->fib6_siblings, fib6_siblings) { 1193 sibling->fib6_nsiblings++; 1194 BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings); 1195 fib6_nsiblings++; 1196 } 1197 BUG_ON(fib6_nsiblings != rt->fib6_nsiblings); 1198 rt6_multipath_rebalance(temp_sibling); 1199 } 1200 1201 /* 1202 * insert node 1203 */ 1204 if (!replace) { 1205 if (!add) 1206 pr_warn("NLM_F_CREATE should be set when creating new route\n"); 1207 1208 add: 1209 nlflags |= NLM_F_CREATE; 1210 1211 /* The route should only be notified if it is the first 1212 * route in the node or if it is added as a sibling 1213 * route to the first route in the node. 1214 */ 1215 if (!info->skip_notify_kernel && 1216 (notify_sibling_rt || ins == &fn->leaf)) { 1217 enum fib_event_type fib_event; 1218 1219 if (notify_sibling_rt) 1220 fib_event = FIB_EVENT_ENTRY_APPEND; 1221 else 1222 fib_event = FIB_EVENT_ENTRY_REPLACE; 1223 err = call_fib6_entry_notifiers(info->nl_net, 1224 fib_event, rt, 1225 extack); 1226 if (err) { 1227 struct fib6_info *sibling, *next_sibling; 1228 1229 /* If the route has siblings, then it first 1230 * needs to be unlinked from them. 1231 */ 1232 if (!rt->fib6_nsiblings) 1233 return err; 1234 1235 list_for_each_entry_safe(sibling, next_sibling, 1236 &rt->fib6_siblings, 1237 fib6_siblings) 1238 sibling->fib6_nsiblings--; 1239 rt->fib6_nsiblings = 0; 1240 list_del_init(&rt->fib6_siblings); 1241 rt6_multipath_rebalance(next_sibling); 1242 return err; 1243 } 1244 } 1245 1246 rcu_assign_pointer(rt->fib6_next, iter); 1247 fib6_info_hold(rt); 1248 rcu_assign_pointer(rt->fib6_node, fn); 1249 rcu_assign_pointer(*ins, rt); 1250 if (!info->skip_notify) 1251 inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags); 1252 info->nl_net->ipv6.rt6_stats->fib_rt_entries++; 1253 1254 if (!(fn->fn_flags & RTN_RTINFO)) { 1255 info->nl_net->ipv6.rt6_stats->fib_route_nodes++; 1256 fn->fn_flags |= RTN_RTINFO; 1257 } 1258 1259 } else { 1260 int nsiblings; 1261 1262 if (!found) { 1263 if (add) 1264 goto add; 1265 pr_warn("NLM_F_REPLACE set, but no existing node found!\n"); 1266 return -ENOENT; 1267 } 1268 1269 if (!info->skip_notify_kernel && ins == &fn->leaf) { 1270 err = call_fib6_entry_notifiers(info->nl_net, 1271 FIB_EVENT_ENTRY_REPLACE, 1272 rt, extack); 1273 if (err) 1274 return err; 1275 } 1276 1277 fib6_info_hold(rt); 1278 rcu_assign_pointer(rt->fib6_node, fn); 1279 rt->fib6_next = iter->fib6_next; 1280 rcu_assign_pointer(*ins, rt); 1281 if (!info->skip_notify) 1282 inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE); 1283 if (!(fn->fn_flags & RTN_RTINFO)) { 1284 info->nl_net->ipv6.rt6_stats->fib_route_nodes++; 1285 fn->fn_flags |= RTN_RTINFO; 1286 } 1287 nsiblings = iter->fib6_nsiblings; 1288 iter->fib6_node = NULL; 1289 fib6_purge_rt(iter, fn, info->nl_net); 1290 if (rcu_access_pointer(fn->rr_ptr) == iter) 1291 fn->rr_ptr = NULL; 1292 fib6_info_release(iter); 1293 1294 if (nsiblings) { 1295 /* Replacing an ECMP route, remove all siblings */ 1296 ins = &rt->fib6_next; 1297 iter = rcu_dereference_protected(*ins, 1298 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1299 while (iter) { 1300 if (iter->fib6_metric > rt->fib6_metric) 1301 break; 1302 if (rt6_qualify_for_ecmp(iter)) { 1303 *ins = iter->fib6_next; 1304 iter->fib6_node = NULL; 1305 fib6_purge_rt(iter, fn, info->nl_net); 1306 if (rcu_access_pointer(fn->rr_ptr) == iter) 1307 fn->rr_ptr = NULL; 1308 fib6_info_release(iter); 1309 nsiblings--; 1310 info->nl_net->ipv6.rt6_stats->fib_rt_entries--; 1311 } else { 1312 ins = &iter->fib6_next; 1313 } 1314 iter = rcu_dereference_protected(*ins, 1315 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1316 } 1317 WARN_ON(nsiblings != 0); 1318 } 1319 } 1320 1321 return 0; 1322 } 1323 1324 static void fib6_start_gc(struct net *net, struct fib6_info *rt) 1325 { 1326 if (!timer_pending(&net->ipv6.ip6_fib_timer) && 1327 (rt->fib6_flags & RTF_EXPIRES)) 1328 mod_timer(&net->ipv6.ip6_fib_timer, 1329 jiffies + net->ipv6.sysctl.ip6_rt_gc_interval); 1330 } 1331 1332 void fib6_force_start_gc(struct net *net) 1333 { 1334 if (!timer_pending(&net->ipv6.ip6_fib_timer)) 1335 mod_timer(&net->ipv6.ip6_fib_timer, 1336 jiffies + net->ipv6.sysctl.ip6_rt_gc_interval); 1337 } 1338 1339 static void __fib6_update_sernum_upto_root(struct fib6_info *rt, 1340 int sernum) 1341 { 1342 struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node, 1343 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1344 1345 /* paired with smp_rmb() in fib6_get_cookie_safe() */ 1346 smp_wmb(); 1347 while (fn) { 1348 WRITE_ONCE(fn->fn_sernum, sernum); 1349 fn = rcu_dereference_protected(fn->parent, 1350 lockdep_is_held(&rt->fib6_table->tb6_lock)); 1351 } 1352 } 1353 1354 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt) 1355 { 1356 __fib6_update_sernum_upto_root(rt, fib6_new_sernum(net)); 1357 } 1358 1359 /* allow ipv4 to update sernum via ipv6_stub */ 1360 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i) 1361 { 1362 spin_lock_bh(&f6i->fib6_table->tb6_lock); 1363 fib6_update_sernum_upto_root(net, f6i); 1364 spin_unlock_bh(&f6i->fib6_table->tb6_lock); 1365 } 1366 1367 /* 1368 * Add routing information to the routing tree. 1369 * <destination addr>/<source addr> 1370 * with source addr info in sub-trees 1371 * Need to own table->tb6_lock 1372 */ 1373 1374 int fib6_add(struct fib6_node *root, struct fib6_info *rt, 1375 struct nl_info *info, struct netlink_ext_ack *extack) 1376 { 1377 struct fib6_table *table = rt->fib6_table; 1378 struct fib6_node *fn; 1379 #ifdef CONFIG_IPV6_SUBTREES 1380 struct fib6_node *pn = NULL; 1381 #endif 1382 int err = -ENOMEM; 1383 int allow_create = 1; 1384 int replace_required = 0; 1385 1386 if (info->nlh) { 1387 if (!(info->nlh->nlmsg_flags & NLM_F_CREATE)) 1388 allow_create = 0; 1389 if (info->nlh->nlmsg_flags & NLM_F_REPLACE) 1390 replace_required = 1; 1391 } 1392 if (!allow_create && !replace_required) 1393 pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n"); 1394 1395 fn = fib6_add_1(info->nl_net, table, root, 1396 &rt->fib6_dst.addr, rt->fib6_dst.plen, 1397 offsetof(struct fib6_info, fib6_dst), allow_create, 1398 replace_required, extack); 1399 if (IS_ERR(fn)) { 1400 err = PTR_ERR(fn); 1401 fn = NULL; 1402 goto out; 1403 } 1404 1405 #ifdef CONFIG_IPV6_SUBTREES 1406 pn = fn; 1407 1408 if (rt->fib6_src.plen) { 1409 struct fib6_node *sn; 1410 1411 if (!rcu_access_pointer(fn->subtree)) { 1412 struct fib6_node *sfn; 1413 1414 /* 1415 * Create subtree. 1416 * 1417 * fn[main tree] 1418 * | 1419 * sfn[subtree root] 1420 * \ 1421 * sn[new leaf node] 1422 */ 1423 1424 /* Create subtree root node */ 1425 sfn = node_alloc(info->nl_net); 1426 if (!sfn) 1427 goto failure; 1428 1429 fib6_info_hold(info->nl_net->ipv6.fib6_null_entry); 1430 rcu_assign_pointer(sfn->leaf, 1431 info->nl_net->ipv6.fib6_null_entry); 1432 sfn->fn_flags = RTN_ROOT; 1433 1434 /* Now add the first leaf node to new subtree */ 1435 1436 sn = fib6_add_1(info->nl_net, table, sfn, 1437 &rt->fib6_src.addr, rt->fib6_src.plen, 1438 offsetof(struct fib6_info, fib6_src), 1439 allow_create, replace_required, extack); 1440 1441 if (IS_ERR(sn)) { 1442 /* If it is failed, discard just allocated 1443 root, and then (in failure) stale node 1444 in main tree. 1445 */ 1446 node_free_immediate(info->nl_net, sfn); 1447 err = PTR_ERR(sn); 1448 goto failure; 1449 } 1450 1451 /* Now link new subtree to main tree */ 1452 rcu_assign_pointer(sfn->parent, fn); 1453 rcu_assign_pointer(fn->subtree, sfn); 1454 } else { 1455 sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn), 1456 &rt->fib6_src.addr, rt->fib6_src.plen, 1457 offsetof(struct fib6_info, fib6_src), 1458 allow_create, replace_required, extack); 1459 1460 if (IS_ERR(sn)) { 1461 err = PTR_ERR(sn); 1462 goto failure; 1463 } 1464 } 1465 1466 if (!rcu_access_pointer(fn->leaf)) { 1467 if (fn->fn_flags & RTN_TL_ROOT) { 1468 /* put back null_entry for root node */ 1469 rcu_assign_pointer(fn->leaf, 1470 info->nl_net->ipv6.fib6_null_entry); 1471 } else { 1472 fib6_info_hold(rt); 1473 rcu_assign_pointer(fn->leaf, rt); 1474 } 1475 } 1476 fn = sn; 1477 } 1478 #endif 1479 1480 err = fib6_add_rt2node(fn, rt, info, extack); 1481 if (!err) { 1482 if (rt->nh) 1483 list_add(&rt->nh_list, &rt->nh->f6i_list); 1484 __fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net)); 1485 fib6_start_gc(info->nl_net, rt); 1486 } 1487 1488 out: 1489 if (err) { 1490 #ifdef CONFIG_IPV6_SUBTREES 1491 /* 1492 * If fib6_add_1 has cleared the old leaf pointer in the 1493 * super-tree leaf node we have to find a new one for it. 1494 */ 1495 if (pn != fn) { 1496 struct fib6_info *pn_leaf = 1497 rcu_dereference_protected(pn->leaf, 1498 lockdep_is_held(&table->tb6_lock)); 1499 if (pn_leaf == rt) { 1500 pn_leaf = NULL; 1501 RCU_INIT_POINTER(pn->leaf, NULL); 1502 fib6_info_release(rt); 1503 } 1504 if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) { 1505 pn_leaf = fib6_find_prefix(info->nl_net, table, 1506 pn); 1507 if (!pn_leaf) 1508 pn_leaf = 1509 info->nl_net->ipv6.fib6_null_entry; 1510 fib6_info_hold(pn_leaf); 1511 rcu_assign_pointer(pn->leaf, pn_leaf); 1512 } 1513 } 1514 #endif 1515 goto failure; 1516 } else if (fib6_requires_src(rt)) { 1517 fib6_routes_require_src_inc(info->nl_net); 1518 } 1519 return err; 1520 1521 failure: 1522 /* fn->leaf could be NULL and fib6_repair_tree() needs to be called if: 1523 * 1. fn is an intermediate node and we failed to add the new 1524 * route to it in both subtree creation failure and fib6_add_rt2node() 1525 * failure case. 1526 * 2. fn is the root node in the table and we fail to add the first 1527 * default route to it. 1528 */ 1529 if (fn && 1530 (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) || 1531 (fn->fn_flags & RTN_TL_ROOT && 1532 !rcu_access_pointer(fn->leaf)))) 1533 fib6_repair_tree(info->nl_net, table, fn); 1534 return err; 1535 } 1536 1537 /* 1538 * Routing tree lookup 1539 * 1540 */ 1541 1542 struct lookup_args { 1543 int offset; /* key offset on fib6_info */ 1544 const struct in6_addr *addr; /* search key */ 1545 }; 1546 1547 static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root, 1548 struct lookup_args *args) 1549 { 1550 struct fib6_node *fn; 1551 __be32 dir; 1552 1553 if (unlikely(args->offset == 0)) 1554 return NULL; 1555 1556 /* 1557 * Descend on a tree 1558 */ 1559 1560 fn = root; 1561 1562 for (;;) { 1563 struct fib6_node *next; 1564 1565 dir = addr_bit_set(args->addr, fn->fn_bit); 1566 1567 next = dir ? rcu_dereference(fn->right) : 1568 rcu_dereference(fn->left); 1569 1570 if (next) { 1571 fn = next; 1572 continue; 1573 } 1574 break; 1575 } 1576 1577 while (fn) { 1578 struct fib6_node *subtree = FIB6_SUBTREE(fn); 1579 1580 if (subtree || fn->fn_flags & RTN_RTINFO) { 1581 struct fib6_info *leaf = rcu_dereference(fn->leaf); 1582 struct rt6key *key; 1583 1584 if (!leaf) 1585 goto backtrack; 1586 1587 key = (struct rt6key *) ((u8 *)leaf + args->offset); 1588 1589 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) { 1590 #ifdef CONFIG_IPV6_SUBTREES 1591 if (subtree) { 1592 struct fib6_node *sfn; 1593 sfn = fib6_node_lookup_1(subtree, 1594 args + 1); 1595 if (!sfn) 1596 goto backtrack; 1597 fn = sfn; 1598 } 1599 #endif 1600 if (fn->fn_flags & RTN_RTINFO) 1601 return fn; 1602 } 1603 } 1604 backtrack: 1605 if (fn->fn_flags & RTN_ROOT) 1606 break; 1607 1608 fn = rcu_dereference(fn->parent); 1609 } 1610 1611 return NULL; 1612 } 1613 1614 /* called with rcu_read_lock() held 1615 */ 1616 struct fib6_node *fib6_node_lookup(struct fib6_node *root, 1617 const struct in6_addr *daddr, 1618 const struct in6_addr *saddr) 1619 { 1620 struct fib6_node *fn; 1621 struct lookup_args args[] = { 1622 { 1623 .offset = offsetof(struct fib6_info, fib6_dst), 1624 .addr = daddr, 1625 }, 1626 #ifdef CONFIG_IPV6_SUBTREES 1627 { 1628 .offset = offsetof(struct fib6_info, fib6_src), 1629 .addr = saddr, 1630 }, 1631 #endif 1632 { 1633 .offset = 0, /* sentinel */ 1634 } 1635 }; 1636 1637 fn = fib6_node_lookup_1(root, daddr ? args : args + 1); 1638 if (!fn || fn->fn_flags & RTN_TL_ROOT) 1639 fn = root; 1640 1641 return fn; 1642 } 1643 1644 /* 1645 * Get node with specified destination prefix (and source prefix, 1646 * if subtrees are used) 1647 * exact_match == true means we try to find fn with exact match of 1648 * the passed in prefix addr 1649 * exact_match == false means we try to find fn with longest prefix 1650 * match of the passed in prefix addr. This is useful for finding fn 1651 * for cached route as it will be stored in the exception table under 1652 * the node with longest prefix length. 1653 */ 1654 1655 1656 static struct fib6_node *fib6_locate_1(struct fib6_node *root, 1657 const struct in6_addr *addr, 1658 int plen, int offset, 1659 bool exact_match) 1660 { 1661 struct fib6_node *fn, *prev = NULL; 1662 1663 for (fn = root; fn ; ) { 1664 struct fib6_info *leaf = rcu_dereference(fn->leaf); 1665 struct rt6key *key; 1666 1667 /* This node is being deleted */ 1668 if (!leaf) { 1669 if (plen <= fn->fn_bit) 1670 goto out; 1671 else 1672 goto next; 1673 } 1674 1675 key = (struct rt6key *)((u8 *)leaf + offset); 1676 1677 /* 1678 * Prefix match 1679 */ 1680 if (plen < fn->fn_bit || 1681 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) 1682 goto out; 1683 1684 if (plen == fn->fn_bit) 1685 return fn; 1686 1687 if (fn->fn_flags & RTN_RTINFO) 1688 prev = fn; 1689 1690 next: 1691 /* 1692 * We have more bits to go 1693 */ 1694 if (addr_bit_set(addr, fn->fn_bit)) 1695 fn = rcu_dereference(fn->right); 1696 else 1697 fn = rcu_dereference(fn->left); 1698 } 1699 out: 1700 if (exact_match) 1701 return NULL; 1702 else 1703 return prev; 1704 } 1705 1706 struct fib6_node *fib6_locate(struct fib6_node *root, 1707 const struct in6_addr *daddr, int dst_len, 1708 const struct in6_addr *saddr, int src_len, 1709 bool exact_match) 1710 { 1711 struct fib6_node *fn; 1712 1713 fn = fib6_locate_1(root, daddr, dst_len, 1714 offsetof(struct fib6_info, fib6_dst), 1715 exact_match); 1716 1717 #ifdef CONFIG_IPV6_SUBTREES 1718 if (src_len) { 1719 WARN_ON(saddr == NULL); 1720 if (fn) { 1721 struct fib6_node *subtree = FIB6_SUBTREE(fn); 1722 1723 if (subtree) { 1724 fn = fib6_locate_1(subtree, saddr, src_len, 1725 offsetof(struct fib6_info, fib6_src), 1726 exact_match); 1727 } 1728 } 1729 } 1730 #endif 1731 1732 if (fn && fn->fn_flags & RTN_RTINFO) 1733 return fn; 1734 1735 return NULL; 1736 } 1737 1738 1739 /* 1740 * Deletion 1741 * 1742 */ 1743 1744 static struct fib6_info *fib6_find_prefix(struct net *net, 1745 struct fib6_table *table, 1746 struct fib6_node *fn) 1747 { 1748 struct fib6_node *child_left, *child_right; 1749 1750 if (fn->fn_flags & RTN_ROOT) 1751 return net->ipv6.fib6_null_entry; 1752 1753 while (fn) { 1754 child_left = rcu_dereference_protected(fn->left, 1755 lockdep_is_held(&table->tb6_lock)); 1756 child_right = rcu_dereference_protected(fn->right, 1757 lockdep_is_held(&table->tb6_lock)); 1758 if (child_left) 1759 return rcu_dereference_protected(child_left->leaf, 1760 lockdep_is_held(&table->tb6_lock)); 1761 if (child_right) 1762 return rcu_dereference_protected(child_right->leaf, 1763 lockdep_is_held(&table->tb6_lock)); 1764 1765 fn = FIB6_SUBTREE(fn); 1766 } 1767 return NULL; 1768 } 1769 1770 /* 1771 * Called to trim the tree of intermediate nodes when possible. "fn" 1772 * is the node we want to try and remove. 1773 * Need to own table->tb6_lock 1774 */ 1775 1776 static struct fib6_node *fib6_repair_tree(struct net *net, 1777 struct fib6_table *table, 1778 struct fib6_node *fn) 1779 { 1780 int children; 1781 int nstate; 1782 struct fib6_node *child; 1783 struct fib6_walker *w; 1784 int iter = 0; 1785 1786 /* Set fn->leaf to null_entry for root node. */ 1787 if (fn->fn_flags & RTN_TL_ROOT) { 1788 rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry); 1789 return fn; 1790 } 1791 1792 for (;;) { 1793 struct fib6_node *fn_r = rcu_dereference_protected(fn->right, 1794 lockdep_is_held(&table->tb6_lock)); 1795 struct fib6_node *fn_l = rcu_dereference_protected(fn->left, 1796 lockdep_is_held(&table->tb6_lock)); 1797 struct fib6_node *pn = rcu_dereference_protected(fn->parent, 1798 lockdep_is_held(&table->tb6_lock)); 1799 struct fib6_node *pn_r = rcu_dereference_protected(pn->right, 1800 lockdep_is_held(&table->tb6_lock)); 1801 struct fib6_node *pn_l = rcu_dereference_protected(pn->left, 1802 lockdep_is_held(&table->tb6_lock)); 1803 struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf, 1804 lockdep_is_held(&table->tb6_lock)); 1805 struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf, 1806 lockdep_is_held(&table->tb6_lock)); 1807 struct fib6_info *new_fn_leaf; 1808 1809 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter); 1810 iter++; 1811 1812 WARN_ON(fn->fn_flags & RTN_RTINFO); 1813 WARN_ON(fn->fn_flags & RTN_TL_ROOT); 1814 WARN_ON(fn_leaf); 1815 1816 children = 0; 1817 child = NULL; 1818 if (fn_r) { 1819 child = fn_r; 1820 children |= 1; 1821 } 1822 if (fn_l) { 1823 child = fn_l; 1824 children |= 2; 1825 } 1826 1827 if (children == 3 || FIB6_SUBTREE(fn) 1828 #ifdef CONFIG_IPV6_SUBTREES 1829 /* Subtree root (i.e. fn) may have one child */ 1830 || (children && fn->fn_flags & RTN_ROOT) 1831 #endif 1832 ) { 1833 new_fn_leaf = fib6_find_prefix(net, table, fn); 1834 #if RT6_DEBUG >= 2 1835 if (!new_fn_leaf) { 1836 WARN_ON(!new_fn_leaf); 1837 new_fn_leaf = net->ipv6.fib6_null_entry; 1838 } 1839 #endif 1840 fib6_info_hold(new_fn_leaf); 1841 rcu_assign_pointer(fn->leaf, new_fn_leaf); 1842 return pn; 1843 } 1844 1845 #ifdef CONFIG_IPV6_SUBTREES 1846 if (FIB6_SUBTREE(pn) == fn) { 1847 WARN_ON(!(fn->fn_flags & RTN_ROOT)); 1848 RCU_INIT_POINTER(pn->subtree, NULL); 1849 nstate = FWS_L; 1850 } else { 1851 WARN_ON(fn->fn_flags & RTN_ROOT); 1852 #endif 1853 if (pn_r == fn) 1854 rcu_assign_pointer(pn->right, child); 1855 else if (pn_l == fn) 1856 rcu_assign_pointer(pn->left, child); 1857 #if RT6_DEBUG >= 2 1858 else 1859 WARN_ON(1); 1860 #endif 1861 if (child) 1862 rcu_assign_pointer(child->parent, pn); 1863 nstate = FWS_R; 1864 #ifdef CONFIG_IPV6_SUBTREES 1865 } 1866 #endif 1867 1868 read_lock(&net->ipv6.fib6_walker_lock); 1869 FOR_WALKERS(net, w) { 1870 if (!child) { 1871 if (w->node == fn) { 1872 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate); 1873 w->node = pn; 1874 w->state = nstate; 1875 } 1876 } else { 1877 if (w->node == fn) { 1878 w->node = child; 1879 if (children&2) { 1880 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); 1881 w->state = w->state >= FWS_R ? FWS_U : FWS_INIT; 1882 } else { 1883 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state); 1884 w->state = w->state >= FWS_C ? FWS_U : FWS_INIT; 1885 } 1886 } 1887 } 1888 } 1889 read_unlock(&net->ipv6.fib6_walker_lock); 1890 1891 node_free(net, fn); 1892 if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn)) 1893 return pn; 1894 1895 RCU_INIT_POINTER(pn->leaf, NULL); 1896 fib6_info_release(pn_leaf); 1897 fn = pn; 1898 } 1899 } 1900 1901 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, 1902 struct fib6_info __rcu **rtp, struct nl_info *info) 1903 { 1904 struct fib6_info *leaf, *replace_rt = NULL; 1905 struct fib6_walker *w; 1906 struct fib6_info *rt = rcu_dereference_protected(*rtp, 1907 lockdep_is_held(&table->tb6_lock)); 1908 struct net *net = info->nl_net; 1909 bool notify_del = false; 1910 1911 RT6_TRACE("fib6_del_route\n"); 1912 1913 /* If the deleted route is the first in the node and it is not part of 1914 * a multipath route, then we need to replace it with the next route 1915 * in the node, if exists. 1916 */ 1917 leaf = rcu_dereference_protected(fn->leaf, 1918 lockdep_is_held(&table->tb6_lock)); 1919 if (leaf == rt && !rt->fib6_nsiblings) { 1920 if (rcu_access_pointer(rt->fib6_next)) 1921 replace_rt = rcu_dereference_protected(rt->fib6_next, 1922 lockdep_is_held(&table->tb6_lock)); 1923 else 1924 notify_del = true; 1925 } 1926 1927 /* Unlink it */ 1928 *rtp = rt->fib6_next; 1929 rt->fib6_node = NULL; 1930 net->ipv6.rt6_stats->fib_rt_entries--; 1931 net->ipv6.rt6_stats->fib_discarded_routes++; 1932 1933 /* Reset round-robin state, if necessary */ 1934 if (rcu_access_pointer(fn->rr_ptr) == rt) 1935 fn->rr_ptr = NULL; 1936 1937 /* Remove this entry from other siblings */ 1938 if (rt->fib6_nsiblings) { 1939 struct fib6_info *sibling, *next_sibling; 1940 1941 /* The route is deleted from a multipath route. If this 1942 * multipath route is the first route in the node, then we need 1943 * to emit a delete notification. Otherwise, we need to skip 1944 * the notification. 1945 */ 1946 if (rt->fib6_metric == leaf->fib6_metric && 1947 rt6_qualify_for_ecmp(leaf)) 1948 notify_del = true; 1949 list_for_each_entry_safe(sibling, next_sibling, 1950 &rt->fib6_siblings, fib6_siblings) 1951 sibling->fib6_nsiblings--; 1952 rt->fib6_nsiblings = 0; 1953 list_del_init(&rt->fib6_siblings); 1954 rt6_multipath_rebalance(next_sibling); 1955 } 1956 1957 /* Adjust walkers */ 1958 read_lock(&net->ipv6.fib6_walker_lock); 1959 FOR_WALKERS(net, w) { 1960 if (w->state == FWS_C && w->leaf == rt) { 1961 RT6_TRACE("walker %p adjusted by delroute\n", w); 1962 w->leaf = rcu_dereference_protected(rt->fib6_next, 1963 lockdep_is_held(&table->tb6_lock)); 1964 if (!w->leaf) 1965 w->state = FWS_U; 1966 } 1967 } 1968 read_unlock(&net->ipv6.fib6_walker_lock); 1969 1970 /* If it was last route, call fib6_repair_tree() to: 1971 * 1. For root node, put back null_entry as how the table was created. 1972 * 2. For other nodes, expunge its radix tree node. 1973 */ 1974 if (!rcu_access_pointer(fn->leaf)) { 1975 if (!(fn->fn_flags & RTN_TL_ROOT)) { 1976 fn->fn_flags &= ~RTN_RTINFO; 1977 net->ipv6.rt6_stats->fib_route_nodes--; 1978 } 1979 fn = fib6_repair_tree(net, table, fn); 1980 } 1981 1982 fib6_purge_rt(rt, fn, net); 1983 1984 if (!info->skip_notify_kernel) { 1985 if (notify_del) 1986 call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, 1987 rt, NULL); 1988 else if (replace_rt) 1989 call_fib6_entry_notifiers_replace(net, replace_rt); 1990 } 1991 if (!info->skip_notify) 1992 inet6_rt_notify(RTM_DELROUTE, rt, info, 0); 1993 1994 fib6_info_release(rt); 1995 } 1996 1997 /* Need to own table->tb6_lock */ 1998 int fib6_del(struct fib6_info *rt, struct nl_info *info) 1999 { 2000 struct net *net = info->nl_net; 2001 struct fib6_info __rcu **rtp; 2002 struct fib6_info __rcu **rtp_next; 2003 struct fib6_table *table; 2004 struct fib6_node *fn; 2005 2006 if (rt == net->ipv6.fib6_null_entry) 2007 return -ENOENT; 2008 2009 table = rt->fib6_table; 2010 fn = rcu_dereference_protected(rt->fib6_node, 2011 lockdep_is_held(&table->tb6_lock)); 2012 if (!fn) 2013 return -ENOENT; 2014 2015 WARN_ON(!(fn->fn_flags & RTN_RTINFO)); 2016 2017 /* 2018 * Walk the leaf entries looking for ourself 2019 */ 2020 2021 for (rtp = &fn->leaf; *rtp; rtp = rtp_next) { 2022 struct fib6_info *cur = rcu_dereference_protected(*rtp, 2023 lockdep_is_held(&table->tb6_lock)); 2024 if (rt == cur) { 2025 if (fib6_requires_src(cur)) 2026 fib6_routes_require_src_dec(info->nl_net); 2027 fib6_del_route(table, fn, rtp, info); 2028 return 0; 2029 } 2030 rtp_next = &cur->fib6_next; 2031 } 2032 return -ENOENT; 2033 } 2034 2035 /* 2036 * Tree traversal function. 2037 * 2038 * Certainly, it is not interrupt safe. 2039 * However, it is internally reenterable wrt itself and fib6_add/fib6_del. 2040 * It means, that we can modify tree during walking 2041 * and use this function for garbage collection, clone pruning, 2042 * cleaning tree when a device goes down etc. etc. 2043 * 2044 * It guarantees that every node will be traversed, 2045 * and that it will be traversed only once. 2046 * 2047 * Callback function w->func may return: 2048 * 0 -> continue walking. 2049 * positive value -> walking is suspended (used by tree dumps, 2050 * and probably by gc, if it will be split to several slices) 2051 * negative value -> terminate walking. 2052 * 2053 * The function itself returns: 2054 * 0 -> walk is complete. 2055 * >0 -> walk is incomplete (i.e. suspended) 2056 * <0 -> walk is terminated by an error. 2057 * 2058 * This function is called with tb6_lock held. 2059 */ 2060 2061 static int fib6_walk_continue(struct fib6_walker *w) 2062 { 2063 struct fib6_node *fn, *pn, *left, *right; 2064 2065 /* w->root should always be table->tb6_root */ 2066 WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT)); 2067 2068 for (;;) { 2069 fn = w->node; 2070 if (!fn) 2071 return 0; 2072 2073 switch (w->state) { 2074 #ifdef CONFIG_IPV6_SUBTREES 2075 case FWS_S: 2076 if (FIB6_SUBTREE(fn)) { 2077 w->node = FIB6_SUBTREE(fn); 2078 continue; 2079 } 2080 w->state = FWS_L; 2081 fallthrough; 2082 #endif 2083 case FWS_L: 2084 left = rcu_dereference_protected(fn->left, 1); 2085 if (left) { 2086 w->node = left; 2087 w->state = FWS_INIT; 2088 continue; 2089 } 2090 w->state = FWS_R; 2091 fallthrough; 2092 case FWS_R: 2093 right = rcu_dereference_protected(fn->right, 1); 2094 if (right) { 2095 w->node = right; 2096 w->state = FWS_INIT; 2097 continue; 2098 } 2099 w->state = FWS_C; 2100 w->leaf = rcu_dereference_protected(fn->leaf, 1); 2101 fallthrough; 2102 case FWS_C: 2103 if (w->leaf && fn->fn_flags & RTN_RTINFO) { 2104 int err; 2105 2106 if (w->skip) { 2107 w->skip--; 2108 goto skip; 2109 } 2110 2111 err = w->func(w); 2112 if (err) 2113 return err; 2114 2115 w->count++; 2116 continue; 2117 } 2118 skip: 2119 w->state = FWS_U; 2120 fallthrough; 2121 case FWS_U: 2122 if (fn == w->root) 2123 return 0; 2124 pn = rcu_dereference_protected(fn->parent, 1); 2125 left = rcu_dereference_protected(pn->left, 1); 2126 right = rcu_dereference_protected(pn->right, 1); 2127 w->node = pn; 2128 #ifdef CONFIG_IPV6_SUBTREES 2129 if (FIB6_SUBTREE(pn) == fn) { 2130 WARN_ON(!(fn->fn_flags & RTN_ROOT)); 2131 w->state = FWS_L; 2132 continue; 2133 } 2134 #endif 2135 if (left == fn) { 2136 w->state = FWS_R; 2137 continue; 2138 } 2139 if (right == fn) { 2140 w->state = FWS_C; 2141 w->leaf = rcu_dereference_protected(w->node->leaf, 1); 2142 continue; 2143 } 2144 #if RT6_DEBUG >= 2 2145 WARN_ON(1); 2146 #endif 2147 } 2148 } 2149 } 2150 2151 static int fib6_walk(struct net *net, struct fib6_walker *w) 2152 { 2153 int res; 2154 2155 w->state = FWS_INIT; 2156 w->node = w->root; 2157 2158 fib6_walker_link(net, w); 2159 res = fib6_walk_continue(w); 2160 if (res <= 0) 2161 fib6_walker_unlink(net, w); 2162 return res; 2163 } 2164 2165 static int fib6_clean_node(struct fib6_walker *w) 2166 { 2167 int res; 2168 struct fib6_info *rt; 2169 struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w); 2170 struct nl_info info = { 2171 .nl_net = c->net, 2172 .skip_notify = c->skip_notify, 2173 }; 2174 2175 if (c->sernum != FIB6_NO_SERNUM_CHANGE && 2176 READ_ONCE(w->node->fn_sernum) != c->sernum) 2177 WRITE_ONCE(w->node->fn_sernum, c->sernum); 2178 2179 if (!c->func) { 2180 WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE); 2181 w->leaf = NULL; 2182 return 0; 2183 } 2184 2185 for_each_fib6_walker_rt(w) { 2186 res = c->func(rt, c->arg); 2187 if (res == -1) { 2188 w->leaf = rt; 2189 res = fib6_del(rt, &info); 2190 if (res) { 2191 #if RT6_DEBUG >= 2 2192 pr_debug("%s: del failed: rt=%p@%p err=%d\n", 2193 __func__, rt, 2194 rcu_access_pointer(rt->fib6_node), 2195 res); 2196 #endif 2197 continue; 2198 } 2199 return 0; 2200 } else if (res == -2) { 2201 if (WARN_ON(!rt->fib6_nsiblings)) 2202 continue; 2203 rt = list_last_entry(&rt->fib6_siblings, 2204 struct fib6_info, fib6_siblings); 2205 continue; 2206 } 2207 WARN_ON(res != 0); 2208 } 2209 w->leaf = rt; 2210 return 0; 2211 } 2212 2213 /* 2214 * Convenient frontend to tree walker. 2215 * 2216 * func is called on each route. 2217 * It may return -2 -> skip multipath route. 2218 * -1 -> delete this route. 2219 * 0 -> continue walking 2220 */ 2221 2222 static void fib6_clean_tree(struct net *net, struct fib6_node *root, 2223 int (*func)(struct fib6_info *, void *arg), 2224 int sernum, void *arg, bool skip_notify) 2225 { 2226 struct fib6_cleaner c; 2227 2228 c.w.root = root; 2229 c.w.func = fib6_clean_node; 2230 c.w.count = 0; 2231 c.w.skip = 0; 2232 c.w.skip_in_node = 0; 2233 c.func = func; 2234 c.sernum = sernum; 2235 c.arg = arg; 2236 c.net = net; 2237 c.skip_notify = skip_notify; 2238 2239 fib6_walk(net, &c.w); 2240 } 2241 2242 static void __fib6_clean_all(struct net *net, 2243 int (*func)(struct fib6_info *, void *), 2244 int sernum, void *arg, bool skip_notify) 2245 { 2246 struct fib6_table *table; 2247 struct hlist_head *head; 2248 unsigned int h; 2249 2250 rcu_read_lock(); 2251 for (h = 0; h < FIB6_TABLE_HASHSZ; h++) { 2252 head = &net->ipv6.fib_table_hash[h]; 2253 hlist_for_each_entry_rcu(table, head, tb6_hlist) { 2254 spin_lock_bh(&table->tb6_lock); 2255 fib6_clean_tree(net, &table->tb6_root, 2256 func, sernum, arg, skip_notify); 2257 spin_unlock_bh(&table->tb6_lock); 2258 } 2259 } 2260 rcu_read_unlock(); 2261 } 2262 2263 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *), 2264 void *arg) 2265 { 2266 __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false); 2267 } 2268 2269 void fib6_clean_all_skip_notify(struct net *net, 2270 int (*func)(struct fib6_info *, void *), 2271 void *arg) 2272 { 2273 __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true); 2274 } 2275 2276 static void fib6_flush_trees(struct net *net) 2277 { 2278 int new_sernum = fib6_new_sernum(net); 2279 2280 __fib6_clean_all(net, NULL, new_sernum, NULL, false); 2281 } 2282 2283 /* 2284 * Garbage collection 2285 */ 2286 2287 static int fib6_age(struct fib6_info *rt, void *arg) 2288 { 2289 struct fib6_gc_args *gc_args = arg; 2290 unsigned long now = jiffies; 2291 2292 /* 2293 * check addrconf expiration here. 2294 * Routes are expired even if they are in use. 2295 */ 2296 2297 if (rt->fib6_flags & RTF_EXPIRES && rt->expires) { 2298 if (time_after(now, rt->expires)) { 2299 RT6_TRACE("expiring %p\n", rt); 2300 return -1; 2301 } 2302 gc_args->more++; 2303 } 2304 2305 /* Also age clones in the exception table. 2306 * Note, that clones are aged out 2307 * only if they are not in use now. 2308 */ 2309 rt6_age_exceptions(rt, gc_args, now); 2310 2311 return 0; 2312 } 2313 2314 void fib6_run_gc(unsigned long expires, struct net *net, bool force) 2315 { 2316 struct fib6_gc_args gc_args; 2317 unsigned long now; 2318 2319 if (force) { 2320 spin_lock_bh(&net->ipv6.fib6_gc_lock); 2321 } else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) { 2322 mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ); 2323 return; 2324 } 2325 gc_args.timeout = expires ? (int)expires : 2326 net->ipv6.sysctl.ip6_rt_gc_interval; 2327 gc_args.more = 0; 2328 2329 fib6_clean_all(net, fib6_age, &gc_args); 2330 now = jiffies; 2331 net->ipv6.ip6_rt_last_gc = now; 2332 2333 if (gc_args.more) 2334 mod_timer(&net->ipv6.ip6_fib_timer, 2335 round_jiffies(now 2336 + net->ipv6.sysctl.ip6_rt_gc_interval)); 2337 else 2338 del_timer(&net->ipv6.ip6_fib_timer); 2339 spin_unlock_bh(&net->ipv6.fib6_gc_lock); 2340 } 2341 2342 static void fib6_gc_timer_cb(struct timer_list *t) 2343 { 2344 struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer); 2345 2346 fib6_run_gc(0, arg, true); 2347 } 2348 2349 static int __net_init fib6_net_init(struct net *net) 2350 { 2351 size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ; 2352 int err; 2353 2354 err = fib6_notifier_init(net); 2355 if (err) 2356 return err; 2357 2358 /* Default to 3-tuple */ 2359 net->ipv6.sysctl.multipath_hash_fields = 2360 FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK; 2361 2362 spin_lock_init(&net->ipv6.fib6_gc_lock); 2363 rwlock_init(&net->ipv6.fib6_walker_lock); 2364 INIT_LIST_HEAD(&net->ipv6.fib6_walkers); 2365 timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0); 2366 2367 net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL); 2368 if (!net->ipv6.rt6_stats) 2369 goto out_notifier; 2370 2371 /* Avoid false sharing : Use at least a full cache line */ 2372 size = max_t(size_t, size, L1_CACHE_BYTES); 2373 2374 net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL); 2375 if (!net->ipv6.fib_table_hash) 2376 goto out_rt6_stats; 2377 2378 net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl), 2379 GFP_KERNEL); 2380 if (!net->ipv6.fib6_main_tbl) 2381 goto out_fib_table_hash; 2382 2383 net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN; 2384 rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf, 2385 net->ipv6.fib6_null_entry); 2386 net->ipv6.fib6_main_tbl->tb6_root.fn_flags = 2387 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO; 2388 inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers); 2389 2390 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 2391 net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl), 2392 GFP_KERNEL); 2393 if (!net->ipv6.fib6_local_tbl) 2394 goto out_fib6_main_tbl; 2395 net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL; 2396 rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf, 2397 net->ipv6.fib6_null_entry); 2398 net->ipv6.fib6_local_tbl->tb6_root.fn_flags = 2399 RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO; 2400 inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers); 2401 #endif 2402 fib6_tables_init(net); 2403 2404 return 0; 2405 2406 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 2407 out_fib6_main_tbl: 2408 kfree(net->ipv6.fib6_main_tbl); 2409 #endif 2410 out_fib_table_hash: 2411 kfree(net->ipv6.fib_table_hash); 2412 out_rt6_stats: 2413 kfree(net->ipv6.rt6_stats); 2414 out_notifier: 2415 fib6_notifier_exit(net); 2416 return -ENOMEM; 2417 } 2418 2419 static void fib6_net_exit(struct net *net) 2420 { 2421 unsigned int i; 2422 2423 del_timer_sync(&net->ipv6.ip6_fib_timer); 2424 2425 for (i = 0; i < FIB6_TABLE_HASHSZ; i++) { 2426 struct hlist_head *head = &net->ipv6.fib_table_hash[i]; 2427 struct hlist_node *tmp; 2428 struct fib6_table *tb; 2429 2430 hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) { 2431 hlist_del(&tb->tb6_hlist); 2432 fib6_free_table(tb); 2433 } 2434 } 2435 2436 kfree(net->ipv6.fib_table_hash); 2437 kfree(net->ipv6.rt6_stats); 2438 fib6_notifier_exit(net); 2439 } 2440 2441 static struct pernet_operations fib6_net_ops = { 2442 .init = fib6_net_init, 2443 .exit = fib6_net_exit, 2444 }; 2445 2446 int __init fib6_init(void) 2447 { 2448 int ret = -ENOMEM; 2449 2450 fib6_node_kmem = kmem_cache_create("fib6_nodes", 2451 sizeof(struct fib6_node), 0, 2452 SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT, 2453 NULL); 2454 if (!fib6_node_kmem) 2455 goto out; 2456 2457 ret = register_pernet_subsys(&fib6_net_ops); 2458 if (ret) 2459 goto out_kmem_cache_create; 2460 2461 ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL, 2462 inet6_dump_fib, 0); 2463 if (ret) 2464 goto out_unregister_subsys; 2465 2466 __fib6_flush_trees = fib6_flush_trees; 2467 out: 2468 return ret; 2469 2470 out_unregister_subsys: 2471 unregister_pernet_subsys(&fib6_net_ops); 2472 out_kmem_cache_create: 2473 kmem_cache_destroy(fib6_node_kmem); 2474 goto out; 2475 } 2476 2477 void fib6_gc_cleanup(void) 2478 { 2479 unregister_pernet_subsys(&fib6_net_ops); 2480 kmem_cache_destroy(fib6_node_kmem); 2481 } 2482 2483 #ifdef CONFIG_PROC_FS 2484 static int ipv6_route_native_seq_show(struct seq_file *seq, void *v) 2485 { 2486 struct fib6_info *rt = v; 2487 struct ipv6_route_iter *iter = seq->private; 2488 struct fib6_nh *fib6_nh = rt->fib6_nh; 2489 unsigned int flags = rt->fib6_flags; 2490 const struct net_device *dev; 2491 2492 if (rt->nh) 2493 fib6_nh = nexthop_fib6_nh(rt->nh); 2494 2495 seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen); 2496 2497 #ifdef CONFIG_IPV6_SUBTREES 2498 seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen); 2499 #else 2500 seq_puts(seq, "00000000000000000000000000000000 00 "); 2501 #endif 2502 if (fib6_nh->fib_nh_gw_family) { 2503 flags |= RTF_GATEWAY; 2504 seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6); 2505 } else { 2506 seq_puts(seq, "00000000000000000000000000000000"); 2507 } 2508 2509 dev = fib6_nh->fib_nh_dev; 2510 seq_printf(seq, " %08x %08x %08x %08x %8s\n", 2511 rt->fib6_metric, refcount_read(&rt->fib6_ref), 0, 2512 flags, dev ? dev->name : ""); 2513 iter->w.leaf = NULL; 2514 return 0; 2515 } 2516 2517 static int ipv6_route_yield(struct fib6_walker *w) 2518 { 2519 struct ipv6_route_iter *iter = w->args; 2520 2521 if (!iter->skip) 2522 return 1; 2523 2524 do { 2525 iter->w.leaf = rcu_dereference_protected( 2526 iter->w.leaf->fib6_next, 2527 lockdep_is_held(&iter->tbl->tb6_lock)); 2528 iter->skip--; 2529 if (!iter->skip && iter->w.leaf) 2530 return 1; 2531 } while (iter->w.leaf); 2532 2533 return 0; 2534 } 2535 2536 static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter, 2537 struct net *net) 2538 { 2539 memset(&iter->w, 0, sizeof(iter->w)); 2540 iter->w.func = ipv6_route_yield; 2541 iter->w.root = &iter->tbl->tb6_root; 2542 iter->w.state = FWS_INIT; 2543 iter->w.node = iter->w.root; 2544 iter->w.args = iter; 2545 iter->sernum = READ_ONCE(iter->w.root->fn_sernum); 2546 INIT_LIST_HEAD(&iter->w.lh); 2547 fib6_walker_link(net, &iter->w); 2548 } 2549 2550 static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl, 2551 struct net *net) 2552 { 2553 unsigned int h; 2554 struct hlist_node *node; 2555 2556 if (tbl) { 2557 h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1; 2558 node = rcu_dereference(hlist_next_rcu(&tbl->tb6_hlist)); 2559 } else { 2560 h = 0; 2561 node = NULL; 2562 } 2563 2564 while (!node && h < FIB6_TABLE_HASHSZ) { 2565 node = rcu_dereference( 2566 hlist_first_rcu(&net->ipv6.fib_table_hash[h++])); 2567 } 2568 return hlist_entry_safe(node, struct fib6_table, tb6_hlist); 2569 } 2570 2571 static void ipv6_route_check_sernum(struct ipv6_route_iter *iter) 2572 { 2573 int sernum = READ_ONCE(iter->w.root->fn_sernum); 2574 2575 if (iter->sernum != sernum) { 2576 iter->sernum = sernum; 2577 iter->w.state = FWS_INIT; 2578 iter->w.node = iter->w.root; 2579 WARN_ON(iter->w.skip); 2580 iter->w.skip = iter->w.count; 2581 } 2582 } 2583 2584 static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos) 2585 { 2586 int r; 2587 struct fib6_info *n; 2588 struct net *net = seq_file_net(seq); 2589 struct ipv6_route_iter *iter = seq->private; 2590 2591 ++(*pos); 2592 if (!v) 2593 goto iter_table; 2594 2595 n = rcu_dereference(((struct fib6_info *)v)->fib6_next); 2596 if (n) 2597 return n; 2598 2599 iter_table: 2600 ipv6_route_check_sernum(iter); 2601 spin_lock_bh(&iter->tbl->tb6_lock); 2602 r = fib6_walk_continue(&iter->w); 2603 spin_unlock_bh(&iter->tbl->tb6_lock); 2604 if (r > 0) { 2605 return iter->w.leaf; 2606 } else if (r < 0) { 2607 fib6_walker_unlink(net, &iter->w); 2608 return NULL; 2609 } 2610 fib6_walker_unlink(net, &iter->w); 2611 2612 iter->tbl = ipv6_route_seq_next_table(iter->tbl, net); 2613 if (!iter->tbl) 2614 return NULL; 2615 2616 ipv6_route_seq_setup_walk(iter, net); 2617 goto iter_table; 2618 } 2619 2620 static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos) 2621 __acquires(RCU) 2622 { 2623 struct net *net = seq_file_net(seq); 2624 struct ipv6_route_iter *iter = seq->private; 2625 2626 rcu_read_lock(); 2627 iter->tbl = ipv6_route_seq_next_table(NULL, net); 2628 iter->skip = *pos; 2629 2630 if (iter->tbl) { 2631 loff_t p = 0; 2632 2633 ipv6_route_seq_setup_walk(iter, net); 2634 return ipv6_route_seq_next(seq, NULL, &p); 2635 } else { 2636 return NULL; 2637 } 2638 } 2639 2640 static bool ipv6_route_iter_active(struct ipv6_route_iter *iter) 2641 { 2642 struct fib6_walker *w = &iter->w; 2643 return w->node && !(w->state == FWS_U && w->node == w->root); 2644 } 2645 2646 static void ipv6_route_native_seq_stop(struct seq_file *seq, void *v) 2647 __releases(RCU) 2648 { 2649 struct net *net = seq_file_net(seq); 2650 struct ipv6_route_iter *iter = seq->private; 2651 2652 if (ipv6_route_iter_active(iter)) 2653 fib6_walker_unlink(net, &iter->w); 2654 2655 rcu_read_unlock(); 2656 } 2657 2658 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL) 2659 static int ipv6_route_prog_seq_show(struct bpf_prog *prog, 2660 struct bpf_iter_meta *meta, 2661 void *v) 2662 { 2663 struct bpf_iter__ipv6_route ctx; 2664 2665 ctx.meta = meta; 2666 ctx.rt = v; 2667 return bpf_iter_run_prog(prog, &ctx); 2668 } 2669 2670 static int ipv6_route_seq_show(struct seq_file *seq, void *v) 2671 { 2672 struct ipv6_route_iter *iter = seq->private; 2673 struct bpf_iter_meta meta; 2674 struct bpf_prog *prog; 2675 int ret; 2676 2677 meta.seq = seq; 2678 prog = bpf_iter_get_info(&meta, false); 2679 if (!prog) 2680 return ipv6_route_native_seq_show(seq, v); 2681 2682 ret = ipv6_route_prog_seq_show(prog, &meta, v); 2683 iter->w.leaf = NULL; 2684 2685 return ret; 2686 } 2687 2688 static void ipv6_route_seq_stop(struct seq_file *seq, void *v) 2689 { 2690 struct bpf_iter_meta meta; 2691 struct bpf_prog *prog; 2692 2693 if (!v) { 2694 meta.seq = seq; 2695 prog = bpf_iter_get_info(&meta, true); 2696 if (prog) 2697 (void)ipv6_route_prog_seq_show(prog, &meta, v); 2698 } 2699 2700 ipv6_route_native_seq_stop(seq, v); 2701 } 2702 #else 2703 static int ipv6_route_seq_show(struct seq_file *seq, void *v) 2704 { 2705 return ipv6_route_native_seq_show(seq, v); 2706 } 2707 2708 static void ipv6_route_seq_stop(struct seq_file *seq, void *v) 2709 { 2710 ipv6_route_native_seq_stop(seq, v); 2711 } 2712 #endif 2713 2714 const struct seq_operations ipv6_route_seq_ops = { 2715 .start = ipv6_route_seq_start, 2716 .next = ipv6_route_seq_next, 2717 .stop = ipv6_route_seq_stop, 2718 .show = ipv6_route_seq_show 2719 }; 2720 #endif /* CONFIG_PROC_FS */ 2721