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
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