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 rcu_head rcu; 202 struct nexthop *nh; 203 struct fib6_nh fib6_nh[]; 204 }; 205 206 struct rt6_info { 207 struct dst_entry dst; 208 struct fib6_info __rcu *from; 209 int sernum; 210 211 struct rt6key rt6i_dst; 212 struct rt6key rt6i_src; 213 struct in6_addr rt6i_gateway; 214 struct inet6_dev *rt6i_idev; 215 u32 rt6i_flags; 216 217 /* more non-fragment space at head required */ 218 unsigned short rt6i_nfheader_len; 219 }; 220 221 struct fib6_result { 222 struct fib6_nh *nh; 223 struct fib6_info *f6i; 224 u32 fib6_flags; 225 u8 fib6_type; 226 struct rt6_info *rt6; 227 }; 228 229 #define for_each_fib6_node_rt_rcu(fn) \ 230 for (rt = rcu_dereference((fn)->leaf); rt; \ 231 rt = rcu_dereference(rt->fib6_next)) 232 233 #define for_each_fib6_walker_rt(w) \ 234 for (rt = (w)->leaf; rt; \ 235 rt = rcu_dereference_protected(rt->fib6_next, 1)) 236 237 #define dst_rt6_info(_ptr) container_of_const(_ptr, struct rt6_info, dst) 238 239 static inline struct inet6_dev *ip6_dst_idev(const struct dst_entry *dst) 240 { 241 return dst_rt6_info(dst)->rt6i_idev; 242 } 243 244 static inline bool fib6_requires_src(const struct fib6_info *rt) 245 { 246 return rt->fib6_src.plen > 0; 247 } 248 249 /* The callers should hold f6i->fib6_table->tb6_lock if a route has ever 250 * been added to a table before. 251 */ 252 static inline void fib6_clean_expires(struct fib6_info *f6i) 253 { 254 f6i->fib6_flags &= ~RTF_EXPIRES; 255 f6i->expires = 0; 256 } 257 258 /* The callers should hold f6i->fib6_table->tb6_lock if a route has ever 259 * been added to a table before. 260 */ 261 static inline void fib6_set_expires(struct fib6_info *f6i, 262 unsigned long expires) 263 { 264 f6i->expires = expires; 265 f6i->fib6_flags |= RTF_EXPIRES; 266 } 267 268 static inline bool fib6_check_expired(const struct fib6_info *f6i) 269 { 270 if (f6i->fib6_flags & RTF_EXPIRES) 271 return time_after(jiffies, f6i->expires); 272 return false; 273 } 274 275 /* Function to safely get fn->fn_sernum for passed in rt 276 * and store result in passed in cookie. 277 * Return true if we can get cookie safely 278 * Return false if not 279 */ 280 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i, 281 u32 *cookie) 282 { 283 struct fib6_node *fn; 284 bool status = false; 285 286 fn = rcu_dereference(f6i->fib6_node); 287 288 if (fn) { 289 *cookie = READ_ONCE(fn->fn_sernum); 290 /* pairs with smp_wmb() in __fib6_update_sernum_upto_root() */ 291 smp_rmb(); 292 status = true; 293 } 294 295 return status; 296 } 297 298 static inline u32 rt6_get_cookie(const struct rt6_info *rt) 299 { 300 struct fib6_info *from; 301 u32 cookie = 0; 302 303 if (rt->sernum) 304 return rt->sernum; 305 306 rcu_read_lock(); 307 308 from = rcu_dereference(rt->from); 309 if (from) 310 fib6_get_cookie_safe(from, &cookie); 311 312 rcu_read_unlock(); 313 314 return cookie; 315 } 316 317 static inline void ip6_rt_put(struct rt6_info *rt) 318 { 319 /* dst_release() accepts a NULL parameter. 320 * We rely on dst being first structure in struct rt6_info 321 */ 322 BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0); 323 dst_release(&rt->dst); 324 } 325 326 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh); 327 void fib6_info_destroy_rcu(struct rcu_head *head); 328 329 static inline void fib6_info_hold(struct fib6_info *f6i) 330 { 331 refcount_inc(&f6i->fib6_ref); 332 } 333 334 static inline bool fib6_info_hold_safe(struct fib6_info *f6i) 335 { 336 return refcount_inc_not_zero(&f6i->fib6_ref); 337 } 338 339 static inline void fib6_info_release(struct fib6_info *f6i) 340 { 341 if (f6i && refcount_dec_and_test(&f6i->fib6_ref)) { 342 DEBUG_NET_WARN_ON_ONCE(!hlist_unhashed(&f6i->gc_link)); 343 call_rcu_hurry(&f6i->rcu, fib6_info_destroy_rcu); 344 } 345 } 346 347 enum fib6_walk_state { 348 #ifdef CONFIG_IPV6_SUBTREES 349 FWS_S, 350 #endif 351 FWS_L, 352 FWS_R, 353 FWS_C, 354 FWS_U 355 }; 356 357 struct fib6_walker { 358 struct list_head lh; 359 struct fib6_node *root, *node; 360 struct fib6_info *leaf; 361 enum fib6_walk_state state; 362 unsigned int skip; 363 unsigned int count; 364 unsigned int skip_in_node; 365 int (*func)(struct fib6_walker *); 366 void *args; 367 }; 368 369 struct rt6_statistics { 370 __u32 fib_nodes; /* all fib6 nodes */ 371 __u32 fib_route_nodes; /* intermediate nodes */ 372 __u32 fib_rt_entries; /* rt entries in fib table */ 373 __u32 fib_rt_cache; /* cached rt entries in exception table */ 374 __u32 fib_discarded_routes; /* total number of routes delete */ 375 376 /* The following stat is not protected by any lock */ 377 atomic_t fib_rt_alloc; /* total number of routes alloced */ 378 }; 379 380 #define RTN_TL_ROOT 0x0001 381 #define RTN_ROOT 0x0002 /* tree root node */ 382 #define RTN_RTINFO 0x0004 /* node with valid routing info */ 383 384 /* 385 * priority levels (or metrics) 386 * 387 */ 388 389 390 struct fib6_table { 391 struct hlist_node tb6_hlist; 392 u32 tb6_id; 393 spinlock_t tb6_lock; 394 struct fib6_node tb6_root; 395 struct inet_peer_base tb6_peers; 396 unsigned int flags; 397 unsigned int fib_seq; 398 struct hlist_head tb6_gc_hlist; /* GC candidates */ 399 #define RT6_TABLE_HAS_DFLT_ROUTER BIT(0) 400 }; 401 402 #define RT6_TABLE_UNSPEC RT_TABLE_UNSPEC 403 #define RT6_TABLE_MAIN RT_TABLE_MAIN 404 #define RT6_TABLE_DFLT RT6_TABLE_MAIN 405 #define RT6_TABLE_INFO RT6_TABLE_MAIN 406 #define RT6_TABLE_PREFIX RT6_TABLE_MAIN 407 408 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 409 #define FIB6_TABLE_MIN 1 410 #define FIB6_TABLE_MAX RT_TABLE_MAX 411 #define RT6_TABLE_LOCAL RT_TABLE_LOCAL 412 #else 413 #define FIB6_TABLE_MIN RT_TABLE_MAIN 414 #define FIB6_TABLE_MAX FIB6_TABLE_MIN 415 #define RT6_TABLE_LOCAL RT6_TABLE_MAIN 416 #endif 417 418 typedef struct rt6_info *(*pol_lookup_t)(struct net *, 419 struct fib6_table *, 420 struct flowi6 *, 421 const struct sk_buff *, int); 422 423 struct fib6_entry_notifier_info { 424 struct fib_notifier_info info; /* must be first */ 425 struct fib6_info *rt; 426 unsigned int nsiblings; 427 }; 428 429 /* 430 * exported functions 431 */ 432 433 struct fib6_table *fib6_get_table(struct net *net, u32 id); 434 struct fib6_table *fib6_new_table(struct net *net, u32 id); 435 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 436 const struct sk_buff *skb, 437 int flags, pol_lookup_t lookup); 438 439 /* called with rcu lock held; can return error pointer 440 * caller needs to select path 441 */ 442 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6, 443 struct fib6_result *res, int flags); 444 445 /* called with rcu lock held; caller needs to select path */ 446 int fib6_table_lookup(struct net *net, struct fib6_table *table, 447 int oif, struct flowi6 *fl6, struct fib6_result *res, 448 int strict); 449 450 void fib6_select_path(const struct net *net, struct fib6_result *res, 451 struct flowi6 *fl6, int oif, bool have_oif_match, 452 const struct sk_buff *skb, int strict); 453 struct fib6_node *fib6_node_lookup(struct fib6_node *root, 454 const struct in6_addr *daddr, 455 const struct in6_addr *saddr); 456 457 struct fib6_node *fib6_locate(struct fib6_node *root, 458 const struct in6_addr *daddr, int dst_len, 459 const struct in6_addr *saddr, int src_len, 460 bool exact_match); 461 462 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg), 463 void *arg); 464 void fib6_clean_all_skip_notify(struct net *net, 465 int (*func)(struct fib6_info *, void *arg), 466 void *arg); 467 468 int fib6_add(struct fib6_node *root, struct fib6_info *rt, 469 struct nl_info *info, struct netlink_ext_ack *extack); 470 int fib6_del(struct fib6_info *rt, struct nl_info *info); 471 472 static inline 473 void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr) 474 { 475 const struct fib6_info *from; 476 477 rcu_read_lock(); 478 479 from = rcu_dereference(rt->from); 480 if (from) 481 *addr = from->fib6_prefsrc.addr; 482 else 483 *addr = in6addr_any; 484 485 rcu_read_unlock(); 486 } 487 488 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, 489 struct fib6_config *cfg, gfp_t gfp_flags, 490 struct netlink_ext_ack *extack); 491 void fib6_nh_release(struct fib6_nh *fib6_nh); 492 void fib6_nh_release_dsts(struct fib6_nh *fib6_nh); 493 494 int call_fib6_entry_notifiers(struct net *net, 495 enum fib_event_type event_type, 496 struct fib6_info *rt, 497 struct netlink_ext_ack *extack); 498 int call_fib6_multipath_entry_notifiers(struct net *net, 499 enum fib_event_type event_type, 500 struct fib6_info *rt, 501 unsigned int nsiblings, 502 struct netlink_ext_ack *extack); 503 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt); 504 void fib6_rt_update(struct net *net, struct fib6_info *rt, 505 struct nl_info *info); 506 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info, 507 unsigned int flags); 508 509 void fib6_run_gc(unsigned long expires, struct net *net, bool force); 510 511 void fib6_gc_cleanup(void); 512 513 int fib6_init(void); 514 515 /* Add the route to the gc list if it is not already there 516 * 517 * The callers should hold f6i->fib6_table->tb6_lock. 518 */ 519 static inline void fib6_add_gc_list(struct fib6_info *f6i) 520 { 521 /* If fib6_node is null, the f6i is not in (or removed from) the 522 * table. 523 * 524 * There is a gap between finding the f6i from the table and 525 * calling this function without the protection of the tb6_lock. 526 * This check makes sure the f6i is not added to the gc list when 527 * it is not on the table. 528 */ 529 if (!rcu_dereference_protected(f6i->fib6_node, 530 lockdep_is_held(&f6i->fib6_table->tb6_lock))) 531 return; 532 533 if (hlist_unhashed(&f6i->gc_link)) 534 hlist_add_head(&f6i->gc_link, &f6i->fib6_table->tb6_gc_hlist); 535 } 536 537 /* Remove the route from the gc list if it is on the list. 538 * 539 * The callers should hold f6i->fib6_table->tb6_lock. 540 */ 541 static inline void fib6_remove_gc_list(struct fib6_info *f6i) 542 { 543 if (!hlist_unhashed(&f6i->gc_link)) 544 hlist_del_init(&f6i->gc_link); 545 } 546 547 struct ipv6_route_iter { 548 struct seq_net_private p; 549 struct fib6_walker w; 550 loff_t skip; 551 struct fib6_table *tbl; 552 int sernum; 553 }; 554 555 extern const struct seq_operations ipv6_route_seq_ops; 556 557 int call_fib6_notifier(struct notifier_block *nb, 558 enum fib_event_type event_type, 559 struct fib_notifier_info *info); 560 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type, 561 struct fib_notifier_info *info); 562 563 int __net_init fib6_notifier_init(struct net *net); 564 void __net_exit fib6_notifier_exit(struct net *net); 565 566 unsigned int fib6_tables_seq_read(struct net *net); 567 int fib6_tables_dump(struct net *net, struct notifier_block *nb, 568 struct netlink_ext_ack *extack); 569 570 void fib6_update_sernum(struct net *net, struct fib6_info *rt); 571 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt); 572 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i); 573 574 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val); 575 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric) 576 { 577 return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric)); 578 } 579 void fib6_info_hw_flags_set(struct net *net, struct fib6_info *f6i, 580 bool offload, bool trap, bool offload_failed); 581 582 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL) 583 struct bpf_iter__ipv6_route { 584 __bpf_md_ptr(struct bpf_iter_meta *, meta); 585 __bpf_md_ptr(struct fib6_info *, rt); 586 }; 587 #endif 588 589 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_output(struct net *net, 590 struct fib6_table *table, 591 struct flowi6 *fl6, 592 const struct sk_buff *skb, 593 int flags)); 594 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_input(struct net *net, 595 struct fib6_table *table, 596 struct flowi6 *fl6, 597 const struct sk_buff *skb, 598 int flags)); 599 INDIRECT_CALLABLE_DECLARE(struct rt6_info *__ip6_route_redirect(struct net *net, 600 struct fib6_table *table, 601 struct flowi6 *fl6, 602 const struct sk_buff *skb, 603 int flags)); 604 INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_lookup(struct net *net, 605 struct fib6_table *table, 606 struct flowi6 *fl6, 607 const struct sk_buff *skb, 608 int flags)); 609 static inline struct rt6_info *pol_lookup_func(pol_lookup_t lookup, 610 struct net *net, 611 struct fib6_table *table, 612 struct flowi6 *fl6, 613 const struct sk_buff *skb, 614 int flags) 615 { 616 return INDIRECT_CALL_4(lookup, 617 ip6_pol_route_output, 618 ip6_pol_route_input, 619 ip6_pol_route_lookup, 620 __ip6_route_redirect, 621 net, table, fl6, skb, flags); 622 } 623 624 #ifdef CONFIG_IPV6_MULTIPLE_TABLES 625 static inline bool fib6_has_custom_rules(const struct net *net) 626 { 627 return net->ipv6.fib6_has_custom_rules; 628 } 629 630 int fib6_rules_init(void); 631 void fib6_rules_cleanup(void); 632 bool fib6_rule_default(const struct fib_rule *rule); 633 int fib6_rules_dump(struct net *net, struct notifier_block *nb, 634 struct netlink_ext_ack *extack); 635 unsigned int fib6_rules_seq_read(struct net *net); 636 637 static inline bool fib6_rules_early_flow_dissect(struct net *net, 638 struct sk_buff *skb, 639 struct flowi6 *fl6, 640 struct flow_keys *flkeys) 641 { 642 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP; 643 644 if (!net->ipv6.fib6_rules_require_fldissect) 645 return false; 646 647 memset(flkeys, 0, sizeof(*flkeys)); 648 __skb_flow_dissect(net, skb, &flow_keys_dissector, 649 flkeys, NULL, 0, 0, 0, flag); 650 651 fl6->fl6_sport = flkeys->ports.src; 652 fl6->fl6_dport = flkeys->ports.dst; 653 fl6->flowi6_proto = flkeys->basic.ip_proto; 654 655 return true; 656 } 657 #else 658 static inline bool fib6_has_custom_rules(const struct net *net) 659 { 660 return false; 661 } 662 static inline int fib6_rules_init(void) 663 { 664 return 0; 665 } 666 static inline void fib6_rules_cleanup(void) 667 { 668 return ; 669 } 670 static inline bool fib6_rule_default(const struct fib_rule *rule) 671 { 672 return true; 673 } 674 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb, 675 struct netlink_ext_ack *extack) 676 { 677 return 0; 678 } 679 static inline unsigned int fib6_rules_seq_read(struct net *net) 680 { 681 return 0; 682 } 683 static inline bool fib6_rules_early_flow_dissect(struct net *net, 684 struct sk_buff *skb, 685 struct flowi6 *fl6, 686 struct flow_keys *flkeys) 687 { 688 return false; 689 } 690 #endif 691 #endif 692