1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 */ 8 9 #ifndef _IP6_FIB_H 10 #define _IP6_FIB_H 11 12 #include <linux/ipv6_route.h> 13 #include <linux/rtnetlink.h> 14 #include <linux/spinlock.h> 15 #include <linux/notifier.h> 16 #include <net/dst.h> 17 #include <net/flow.h> 18 #include <net/ip_fib.h> 19 #include <net/netlink.h> 20 #include <net/inetpeer.h> 21 #include <net/fib_notifier.h> 22 #include <linux/indirect_call_wrapper.h> 23 #include <uapi/linux/bpf.h> 24 25 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 26 #define FIB6_TABLE_HASHSZ 256 27 #else 28 #define FIB6_TABLE_HASHSZ 1 29 #endif 30 31 #define RT6_DEBUG 2 32 33 struct rt6_info; 34 struct fib6_info; 35 36 struct fib6_config { 37 u32 fc_table; 38 u32 fc_metric; 39 int fc_dst_len; 40 int fc_src_len; 41 int fc_ifindex; 42 u32 fc_flags; 43 u32 fc_protocol; 44 u16 fc_type; /* only 8 bits are used */ 45 u16 fc_delete_all_nh : 1, 46 fc_ignore_dev_down:1, 47 __unused : 14; 48 u32 fc_nh_id; 49 50 struct in6_addr fc_dst; 51 struct in6_addr fc_src; 52 struct in6_addr fc_prefsrc; 53 struct in6_addr fc_gateway; 54 55 unsigned long fc_expires; 56 struct nlattr *fc_mx; 57 int fc_mx_len; 58 int fc_mp_len; 59 struct nlattr *fc_mp; 60 61 struct nl_info fc_nlinfo; 62 struct nlattr *fc_encap; 63 u16 fc_encap_type; 64 bool fc_is_fdb; 65 }; 66 67 struct fib6_node { 68 struct fib6_node __rcu *parent; 69 struct fib6_node __rcu *left; 70 struct fib6_node __rcu *right; 71 #ifdef CONFIG_IPV6_SUBTREES 72 struct fib6_node __rcu *subtree; 73 #endif 74 struct fib6_info __rcu *leaf; 75 76 __u16 fn_bit; /* bit key */ 77 __u16 fn_flags; 78 int fn_sernum; 79 struct fib6_info __rcu *rr_ptr; 80 struct rcu_head rcu; 81 }; 82 83 struct fib6_gc_args { 84 int timeout; 85 int more; 86 }; 87 88 #ifndef CONFIG_IPV6_SUBTREES 89 #define FIB6_SUBTREE(fn) NULL 90 91 static inline bool fib6_routes_require_src(const struct net *net) 92 { 93 return false; 94 } 95 96 static inline void fib6_routes_require_src_inc(struct net *net) {} 97 static inline void fib6_routes_require_src_dec(struct net *net) {} 98 99 #else 100 101 static inline bool fib6_routes_require_src(const struct net *net) 102 { 103 return net->ipv6.fib6_routes_require_src > 0; 104 } 105 106 static inline void fib6_routes_require_src_inc(struct net *net) 107 { 108 net->ipv6.fib6_routes_require_src++; 109 } 110 111 static inline void fib6_routes_require_src_dec(struct net *net) 112 { 113 net->ipv6.fib6_routes_require_src--; 114 } 115 116 #define FIB6_SUBTREE(fn) (rcu_dereference_protected((fn)->subtree, 1)) 117 #endif 118 119 /* 120 * routing information 121 * 122 */ 123 124 struct rt6key { 125 struct in6_addr addr; 126 int plen; 127 }; 128 129 struct fib6_table; 130 131 struct rt6_exception_bucket { 132 struct hlist_head chain; 133 int depth; 134 }; 135 136 struct rt6_exception { 137 struct hlist_node hlist; 138 struct rt6_info *rt6i; 139 unsigned long stamp; 140 struct rcu_head rcu; 141 }; 142 143 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10 144 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT) 145 #define FIB6_MAX_DEPTH 5 146 147 struct fib6_nh { 148 struct fib_nh_common nh_common; 149 150 #ifdef CONFIG_IPV6_ROUTER_PREF 151 unsigned long last_probe; 152 #endif 153 154 struct rt6_info * __percpu *rt6i_pcpu; 155 struct rt6_exception_bucket __rcu *rt6i_exception_bucket; 156 }; 157 158 struct fib6_info { 159 struct fib6_table *fib6_table; 160 struct fib6_info __rcu *fib6_next; 161 struct fib6_node __rcu *fib6_node; 162 163 /* Multipath routes: 164 * siblings is a list of fib6_info that have the same metric/weight, 165 * destination, but not the same gateway. nsiblings is just a cache 166 * to speed up lookup. 167 */ 168 union { 169 struct list_head fib6_siblings; 170 struct list_head nh_list; 171 }; 172 unsigned int fib6_nsiblings; 173 174 refcount_t fib6_ref; 175 unsigned long expires; 176 177 struct hlist_node gc_link; 178 179 struct dst_metrics *fib6_metrics; 180 #define fib6_pmtu fib6_metrics->metrics[RTAX_MTU-1] 181 182 struct rt6key fib6_dst; 183 u32 fib6_flags; 184 struct rt6key fib6_src; 185 struct rt6key fib6_prefsrc; 186 187 u32 fib6_metric; 188 u8 fib6_protocol; 189 u8 fib6_type; 190 191 u8 offload; 192 u8 trap; 193 u8 offload_failed; 194 195 u8 should_flush:1, 196 dst_nocount:1, 197 dst_nopolicy:1, 198 fib6_destroying:1, 199 unused:4; 200 201 struct list_head purge_link; 202 struct rcu_head rcu; 203 struct nexthop *nh; 204 struct fib6_nh fib6_nh[]; 205 }; 206 207 struct rt6_info { 208 struct dst_entry dst; 209 struct fib6_info __rcu *from; 210 int sernum; 211 212 struct rt6key rt6i_dst; 213 struct rt6key rt6i_src; 214 struct in6_addr rt6i_gateway; 215 struct inet6_dev *rt6i_idev; 216 u32 rt6i_flags; 217 218 /* more non-fragment space at head required */ 219 unsigned short rt6i_nfheader_len; 220 }; 221 222 struct fib6_result { 223 struct fib6_nh *nh; 224 struct fib6_info *f6i; 225 u32 fib6_flags; 226 u8 fib6_type; 227 struct rt6_info *rt6; 228 }; 229 230 #define for_each_fib6_node_rt_rcu(fn) \ 231 for (rt = rcu_dereference((fn)->leaf); rt; \ 232 rt = rcu_dereference(rt->fib6_next)) 233 234 #define for_each_fib6_walker_rt(w) \ 235 for (rt = (w)->leaf; rt; \ 236 rt = rcu_dereference_protected(rt->fib6_next, 1)) 237 238 #define dst_rt6_info(_ptr) container_of_const(_ptr, struct rt6_info, dst) 239 240 static inline struct inet6_dev *ip6_dst_idev(const struct dst_entry *dst) 241 { 242 return dst_rt6_info(dst)->rt6i_idev; 243 } 244 245 static inline bool fib6_requires_src(const struct fib6_info *rt) 246 { 247 return rt->fib6_src.plen > 0; 248 } 249 250 /* The callers should hold f6i->fib6_table->tb6_lock if a route has ever 251 * been added to a table before. 252 */ 253 static inline void fib6_clean_expires(struct fib6_info *f6i) 254 { 255 f6i->fib6_flags &= ~RTF_EXPIRES; 256 f6i->expires = 0; 257 } 258 259 /* The callers should hold f6i->fib6_table->tb6_lock if a route has ever 260 * been added to a table before. 261 */ 262 static inline void fib6_set_expires(struct fib6_info *f6i, 263 unsigned long expires) 264 { 265 f6i->expires = expires; 266 f6i->fib6_flags |= RTF_EXPIRES; 267 } 268 269 static inline bool fib6_check_expired(const struct fib6_info *f6i) 270 { 271 if (f6i->fib6_flags & RTF_EXPIRES) 272 return time_after(jiffies, f6i->expires); 273 return false; 274 } 275 276 /* Function to safely get fn->fn_sernum for passed in rt 277 * and store result in passed in cookie. 278 * Return true if we can get cookie safely 279 * Return false if not 280 */ 281 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i, 282 u32 *cookie) 283 { 284 struct fib6_node *fn; 285 bool status = false; 286 287 fn = rcu_dereference(f6i->fib6_node); 288 289 if (fn) { 290 *cookie = READ_ONCE(fn->fn_sernum); 291 /* pairs with smp_wmb() in __fib6_update_sernum_upto_root() */ 292 smp_rmb(); 293 status = true; 294 } 295 296 return status; 297 } 298 299 static inline u32 rt6_get_cookie(const struct rt6_info *rt) 300 { 301 struct fib6_info *from; 302 u32 cookie = 0; 303 304 if (rt->sernum) 305 return rt->sernum; 306 307 rcu_read_lock(); 308 309 from = rcu_dereference(rt->from); 310 if (from) 311 fib6_get_cookie_safe(from, &cookie); 312 313 rcu_read_unlock(); 314 315 return cookie; 316 } 317 318 static inline void ip6_rt_put(struct rt6_info *rt) 319 { 320 /* dst_release() accepts a NULL parameter. 321 * We rely on dst being first structure in struct rt6_info 322 */ 323 BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0); 324 dst_release(&rt->dst); 325 } 326 327 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh); 328 void fib6_info_destroy_rcu(struct rcu_head *head); 329 330 static inline void fib6_info_hold(struct fib6_info *f6i) 331 { 332 refcount_inc(&f6i->fib6_ref); 333 } 334 335 static inline bool fib6_info_hold_safe(struct fib6_info *f6i) 336 { 337 return refcount_inc_not_zero(&f6i->fib6_ref); 338 } 339 340 static inline void fib6_info_release(struct fib6_info *f6i) 341 { 342 if (f6i && refcount_dec_and_test(&f6i->fib6_ref)) { 343 DEBUG_NET_WARN_ON_ONCE(!hlist_unhashed(&f6i->gc_link)); 344 call_rcu_hurry(&f6i->rcu, fib6_info_destroy_rcu); 345 } 346 } 347 348 enum fib6_walk_state { 349 #ifdef CONFIG_IPV6_SUBTREES 350 FWS_S, 351 #endif 352 FWS_L, 353 FWS_R, 354 FWS_C, 355 FWS_U 356 }; 357 358 struct fib6_walker { 359 struct list_head lh; 360 struct fib6_node *root, *node; 361 struct fib6_info *leaf; 362 enum fib6_walk_state state; 363 unsigned int skip; 364 unsigned int count; 365 unsigned int skip_in_node; 366 int (*func)(struct fib6_walker *); 367 void *args; 368 }; 369 370 struct rt6_statistics { 371 __u32 fib_nodes; /* all fib6 nodes */ 372 __u32 fib_route_nodes; /* intermediate nodes */ 373 __u32 fib_rt_entries; /* rt entries in fib table */ 374 __u32 fib_rt_cache; /* cached rt entries in exception table */ 375 __u32 fib_discarded_routes; /* total number of routes delete */ 376 377 /* The following stat is not protected by any lock */ 378 atomic_t fib_rt_alloc; /* total number of routes alloced */ 379 }; 380 381 #define RTN_TL_ROOT 0x0001 382 #define RTN_ROOT 0x0002 /* tree root node */ 383 #define RTN_RTINFO 0x0004 /* node with valid routing info */ 384 385 /* 386 * priority levels (or metrics) 387 * 388 */ 389 390 391 struct fib6_table { 392 struct hlist_node tb6_hlist; 393 u32 tb6_id; 394 spinlock_t tb6_lock; 395 struct fib6_node tb6_root; 396 struct inet_peer_base tb6_peers; 397 unsigned int flags; 398 unsigned int fib_seq; /* writes protected by rtnl_mutex */ 399 struct hlist_head tb6_gc_hlist; /* GC candidates */ 400 #define RT6_TABLE_HAS_DFLT_ROUTER BIT(0) 401 }; 402 403 #define RT6_TABLE_UNSPEC RT_TABLE_UNSPEC 404 #define RT6_TABLE_MAIN RT_TABLE_MAIN 405 #define RT6_TABLE_DFLT RT6_TABLE_MAIN 406 #define RT6_TABLE_INFO RT6_TABLE_MAIN 407 #define RT6_TABLE_PREFIX RT6_TABLE_MAIN 408 409 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 410 #define FIB6_TABLE_MIN 1 411 #define FIB6_TABLE_MAX RT_TABLE_MAX 412 #define RT6_TABLE_LOCAL RT_TABLE_LOCAL 413 #else 414 #define FIB6_TABLE_MIN RT_TABLE_MAIN 415 #define FIB6_TABLE_MAX FIB6_TABLE_MIN 416 #define RT6_TABLE_LOCAL RT6_TABLE_MAIN 417 #endif 418 419 typedef struct rt6_info *(*pol_lookup_t)(struct net *, 420 struct fib6_table *, 421 struct flowi6 *, 422 const struct sk_buff *, int); 423 424 struct fib6_entry_notifier_info { 425 struct fib_notifier_info info; /* must be first */ 426 struct fib6_info *rt; 427 unsigned int nsiblings; 428 }; 429 430 /* 431 * exported functions 432 */ 433 434 struct fib6_table *fib6_get_table(struct net *net, u32 id); 435 struct fib6_table *fib6_new_table(struct net *net, u32 id); 436 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 437 const struct sk_buff *skb, 438 int flags, pol_lookup_t lookup); 439 440 /* called with rcu lock held; can return error pointer 441 * caller needs to select path 442 */ 443 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 444 struct fib6_result *res, int flags); 445 446 /* called with rcu lock held; caller needs to select path */ 447 int fib6_table_lookup(struct net *net, struct fib6_table *table, 448 int oif, struct flowi6 *fl6, struct fib6_result *res, 449 int strict); 450 451 void fib6_select_path(const struct net *net, struct fib6_result *res, 452 struct flowi6 *fl6, int oif, bool have_oif_match, 453 const struct sk_buff *skb, int strict); 454 struct fib6_node *fib6_node_lookup(struct fib6_node *root, 455 const struct in6_addr *daddr, 456 const struct in6_addr *saddr); 457 458 struct fib6_node *fib6_locate(struct fib6_node *root, 459 const struct in6_addr *daddr, int dst_len, 460 const struct in6_addr *saddr, int src_len, 461 bool exact_match); 462 463 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg), 464 void *arg); 465 void fib6_clean_all_skip_notify(struct net *net, 466 int (*func)(struct fib6_info *, void *arg), 467 void *arg); 468 469 int fib6_add(struct fib6_node *root, struct fib6_info *rt, 470 struct nl_info *info, struct netlink_ext_ack *extack); 471 int fib6_del(struct fib6_info *rt, struct nl_info *info); 472 473 static inline 474 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr) 475 { 476 const struct fib6_info *from; 477 478 rcu_read_lock(); 479 480 from = rcu_dereference(rt->from); 481 if (from) 482 *addr = from->fib6_prefsrc.addr; 483 else 484 *addr = in6addr_any; 485 486 rcu_read_unlock(); 487 } 488 489 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 490 struct fib6_config *cfg, gfp_t gfp_flags, 491 struct netlink_ext_ack *extack); 492 void fib6_nh_release(struct fib6_nh *fib6_nh); 493 void fib6_nh_release_dsts(struct fib6_nh *fib6_nh); 494 495 int call_fib6_entry_notifiers(struct net *net, 496 enum fib_event_type event_type, 497 struct fib6_info *rt, 498 struct netlink_ext_ack *extack); 499 int call_fib6_multipath_entry_notifiers(struct net *net, 500 enum fib_event_type event_type, 501 struct fib6_info *rt, 502 unsigned int nsiblings, 503 struct netlink_ext_ack *extack); 504 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt); 505 void fib6_rt_update(struct net *net, struct fib6_info *rt, 506 struct nl_info *info); 507 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info, 508 unsigned int flags); 509 510 void fib6_age_exceptions(struct fib6_info *rt, struct fib6_gc_args *gc_args, 511 unsigned long now); 512 void fib6_run_gc(unsigned long expires, struct net *net, bool force); 513 void fib6_gc_cleanup(void); 514 515 int fib6_init(void); 516 517 #if IS_ENABLED(CONFIG_IPV6) 518 /* Add the route to the gc list if it is not already there 519 * 520 * The callers should hold f6i->fib6_table->tb6_lock. 521 */ 522 static inline void fib6_add_gc_list(struct fib6_info *f6i) 523 { 524 /* If fib6_node is null, the f6i is not in (or removed from) the 525 * table. 526 * 527 * There is a gap between finding the f6i from the table and 528 * calling this function without the protection of the tb6_lock. 529 * This check makes sure the f6i is not added to the gc list when 530 * it is not on the table. 531 */ 532 if (!rcu_dereference_protected(f6i->fib6_node, 533 lockdep_is_held(&f6i->fib6_table->tb6_lock))) 534 return; 535 536 if (hlist_unhashed(&f6i->gc_link)) 537 hlist_add_head(&f6i->gc_link, &f6i->fib6_table->tb6_gc_hlist); 538 } 539 540 /* Remove the route from the gc list if it is on the list. 541 * 542 * The callers should hold f6i->fib6_table->tb6_lock. 543 */ 544 static inline void fib6_remove_gc_list(struct fib6_info *f6i) 545 { 546 if (!hlist_unhashed(&f6i->gc_link)) 547 hlist_del_init(&f6i->gc_link); 548 } 549 550 static inline void fib6_may_remove_gc_list(struct net *net, 551 struct fib6_info *f6i) 552 { 553 struct fib6_gc_args gc_args; 554 555 if (hlist_unhashed(&f6i->gc_link)) 556 return; 557 558 gc_args.timeout = READ_ONCE(net->ipv6.sysctl.ip6_rt_gc_interval); 559 gc_args.more = 0; 560 561 rcu_read_lock(); 562 fib6_age_exceptions(f6i, &gc_args, jiffies); 563 rcu_read_unlock(); 564 } 565 #endif 566 567 struct ipv6_route_iter { 568 struct seq_net_private p; 569 struct fib6_walker w; 570 loff_t skip; 571 struct fib6_table *tbl; 572 int sernum; 573 }; 574 575 extern const struct seq_operations ipv6_route_seq_ops; 576 577 int call_fib6_notifier(struct notifier_block *nb, 578 enum fib_event_type event_type, 579 struct fib_notifier_info *info); 580 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type, 581 struct fib_notifier_info *info); 582 583 int __net_init fib6_notifier_init(struct net *net); 584 void __net_exit fib6_notifier_exit(struct net *net); 585 586 unsigned int fib6_tables_seq_read(const struct net *net); 587 int fib6_tables_dump(struct net *net, struct notifier_block *nb, 588 struct netlink_ext_ack *extack); 589 590 void fib6_update_sernum(struct net *net, struct fib6_info *rt); 591 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt); 592 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i); 593 594 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val); 595 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric) 596 { 597 return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric)); 598 } 599 void fib6_info_hw_flags_set(struct net *net, struct fib6_info *f6i, 600 bool offload, bool trap, bool offload_failed); 601 602 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL) 603 struct bpf_iter__ipv6_route { 604 __bpf_md_ptr(struct bpf_iter_meta *, meta); 605 __bpf_md_ptr(struct fib6_info *, rt); 606 }; 607 #endif 608 609 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_output(struct net *net, 610 struct fib6_table *table, 611 struct flowi6 *fl6, 612 const struct sk_buff *skb, 613 int flags)); 614 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_input(struct net *net, 615 struct fib6_table *table, 616 struct flowi6 *fl6, 617 const struct sk_buff *skb, 618 int flags)); 619 INDIRECT_CALLABLE_DECLARE(struct rt6_info *__ip6_route_redirect(struct net *net, 620 struct fib6_table *table, 621 struct flowi6 *fl6, 622 const struct sk_buff *skb, 623 int flags)); 624 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_lookup(struct net *net, 625 struct fib6_table *table, 626 struct flowi6 *fl6, 627 const struct sk_buff *skb, 628 int flags)); 629 static inline struct rt6_info *pol_lookup_func(pol_lookup_t lookup, 630 struct net *net, 631 struct fib6_table *table, 632 struct flowi6 *fl6, 633 const struct sk_buff *skb, 634 int flags) 635 { 636 return INDIRECT_CALL_4(lookup, 637 ip6_pol_route_output, 638 ip6_pol_route_input, 639 ip6_pol_route_lookup, 640 __ip6_route_redirect, 641 net, table, fl6, skb, flags); 642 } 643 644 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 645 static inline bool fib6_has_custom_rules(const struct net *net) 646 { 647 return net->ipv6.fib6_has_custom_rules; 648 } 649 650 int fib6_rules_init(void); 651 void fib6_rules_cleanup(void); 652 bool fib6_rule_default(const struct fib_rule *rule); 653 int fib6_rules_dump(struct net *net, struct notifier_block *nb, 654 struct netlink_ext_ack *extack); 655 unsigned int fib6_rules_seq_read(const struct net *net); 656 657 static inline bool fib6_rules_early_flow_dissect(struct net *net, 658 struct sk_buff *skb, 659 struct flowi6 *fl6, 660 struct flow_keys *flkeys) 661 { 662 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 663 664 if (!net->ipv6.fib6_rules_require_fldissect) 665 return false; 666 667 memset(flkeys, 0, sizeof(*flkeys)); 668 __skb_flow_dissect(net, skb, &flow_keys_dissector, 669 flkeys, NULL, 0, 0, 0, flag); 670 671 fl6->fl6_sport = flkeys->ports.src; 672 fl6->fl6_dport = flkeys->ports.dst; 673 fl6->flowi6_proto = flkeys->basic.ip_proto; 674 675 return true; 676 } 677 #else 678 static inline bool fib6_has_custom_rules(const struct net *net) 679 { 680 return false; 681 } 682 static inline int fib6_rules_init(void) 683 { 684 return 0; 685 } 686 static inline void fib6_rules_cleanup(void) 687 { 688 return ; 689 } 690 static inline bool fib6_rule_default(const struct fib_rule *rule) 691 { 692 return true; 693 } 694 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb, 695 struct netlink_ext_ack *extack) 696 { 697 return 0; 698 } 699 static inline unsigned int fib6_rules_seq_read(const struct net *net) 700 { 701 return 0; 702 } 703 static inline bool fib6_rules_early_flow_dissect(struct net *net, 704 struct sk_buff *skb, 705 struct flowi6 *fl6, 706 struct flow_keys *flkeys) 707 { 708 return false; 709 } 710 #endif 711 #endif 712