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
33struct rt6_info;
34struct fib6_info;
35
36struct 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
67struct 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
83struct fib6_gc_args {
84 int timeout;
85 int more;
86};
87
88#ifndef CONFIG_IPV6_SUBTREES
89#define FIB6_SUBTREE(fn) NULL
90
91static inline bool fib6_routes_require_src(const struct net *net)
92{
93 return false;
94}
95
96static inline void fib6_routes_require_src_inc(struct net *net) {}
97static inline void fib6_routes_require_src_dec(struct net *net) {}
98
99#else
100
101static inline bool fib6_routes_require_src(const struct net *net)
102{
103 return net->ipv6.fib6_routes_require_src > 0;
104}
105
106static inline void fib6_routes_require_src_inc(struct net *net)
107{
108 net->ipv6.fib6_routes_require_src++;
109}
110
111static 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
124struct rt6key {
125 struct in6_addr addr;
126 int plen;
127};
128
129struct fib6_table;
130
131struct rt6_exception_bucket {
132 struct hlist_head chain;
133 int depth;
134};
135
136struct 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
147struct 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
158struct 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
206struct 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
221struct 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
237static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
238{
239 return ((struct rt6_info *)dst)->rt6i_idev;
240}
241
242static inline bool fib6_requires_src(const struct fib6_info *rt)
243{
244 return rt->fib6_src.plen > 0;
245}
246
247/* The callers should hold f6i->fib6_table->tb6_lock if a route has ever
248 * been added to a table before.
249 */
250static inline void fib6_clean_expires(struct fib6_info *f6i)
251{
252 f6i->fib6_flags &= ~RTF_EXPIRES;
253 f6i->expires = 0;
254}
255
256/* The callers should hold f6i->fib6_table->tb6_lock if a route has ever
257 * been added to a table before.
258 */
259static inline void fib6_set_expires(struct fib6_info *f6i,
260 unsigned long expires)
261{
262 f6i->expires = expires;
263 f6i->fib6_flags |= RTF_EXPIRES;
264}
265
266static inline bool fib6_check_expired(const struct fib6_info *f6i)
267{
268 if (f6i->fib6_flags & RTF_EXPIRES)
269 return time_after(jiffies, f6i->expires);
270 return false;
271}
272
273/* Function to safely get fn->fn_sernum for passed in rt
274 * and store result in passed in cookie.
275 * Return true if we can get cookie safely
276 * Return false if not
277 */
278static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
279 u32 *cookie)
280{
281 struct fib6_node *fn;
282 bool status = false;
283
284 fn = rcu_dereference(f6i->fib6_node);
285
286 if (fn) {
287 *cookie = READ_ONCE(fn->fn_sernum);
288 /* pairs with smp_wmb() in __fib6_update_sernum_upto_root() */
289 smp_rmb();
290 status = true;
291 }
292
293 return status;
294}
295
296static inline u32 rt6_get_cookie(const struct rt6_info *rt)
297{
298 struct fib6_info *from;
299 u32 cookie = 0;
300
301 if (rt->sernum)
302 return rt->sernum;
303
304 rcu_read_lock();
305
306 from = rcu_dereference(rt->from);
307 if (from)
308 fib6_get_cookie_safe(f6i: from, cookie: &cookie);
309
310 rcu_read_unlock();
311
312 return cookie;
313}
314
315static inline void ip6_rt_put(struct rt6_info *rt)
316{
317 /* dst_release() accepts a NULL parameter.
318 * We rely on dst being first structure in struct rt6_info
319 */
320 BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
321 dst_release(dst: &rt->dst);
322}
323
324struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh);
325void fib6_info_destroy_rcu(struct rcu_head *head);
326
327static inline void fib6_info_hold(struct fib6_info *f6i)
328{
329 refcount_inc(r: &f6i->fib6_ref);
330}
331
332static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
333{
334 return refcount_inc_not_zero(r: &f6i->fib6_ref);
335}
336
337static inline void fib6_info_release(struct fib6_info *f6i)
338{
339 if (f6i && refcount_dec_and_test(r: &f6i->fib6_ref)) {
340 DEBUG_NET_WARN_ON_ONCE(!hlist_unhashed(&f6i->gc_link));
341 call_rcu(head: &f6i->rcu, func: fib6_info_destroy_rcu);
342 }
343}
344
345enum fib6_walk_state {
346#ifdef CONFIG_IPV6_SUBTREES
347 FWS_S,
348#endif
349 FWS_L,
350 FWS_R,
351 FWS_C,
352 FWS_U
353};
354
355struct fib6_walker {
356 struct list_head lh;
357 struct fib6_node *root, *node;
358 struct fib6_info *leaf;
359 enum fib6_walk_state state;
360 unsigned int skip;
361 unsigned int count;
362 unsigned int skip_in_node;
363 int (*func)(struct fib6_walker *);
364 void *args;
365};
366
367struct rt6_statistics {
368 __u32 fib_nodes; /* all fib6 nodes */
369 __u32 fib_route_nodes; /* intermediate nodes */
370 __u32 fib_rt_entries; /* rt entries in fib table */
371 __u32 fib_rt_cache; /* cached rt entries in exception table */
372 __u32 fib_discarded_routes; /* total number of routes delete */
373
374 /* The following stat is not protected by any lock */
375 atomic_t fib_rt_alloc; /* total number of routes alloced */
376};
377
378#define RTN_TL_ROOT 0x0001
379#define RTN_ROOT 0x0002 /* tree root node */
380#define RTN_RTINFO 0x0004 /* node with valid routing info */
381
382/*
383 * priority levels (or metrics)
384 *
385 */
386
387
388struct fib6_table {
389 struct hlist_node tb6_hlist;
390 u32 tb6_id;
391 spinlock_t tb6_lock;
392 struct fib6_node tb6_root;
393 struct inet_peer_base tb6_peers;
394 unsigned int flags;
395 unsigned int fib_seq;
396 struct hlist_head tb6_gc_hlist; /* GC candidates */
397#define RT6_TABLE_HAS_DFLT_ROUTER BIT(0)
398};
399
400#define RT6_TABLE_UNSPEC RT_TABLE_UNSPEC
401#define RT6_TABLE_MAIN RT_TABLE_MAIN
402#define RT6_TABLE_DFLT RT6_TABLE_MAIN
403#define RT6_TABLE_INFO RT6_TABLE_MAIN
404#define RT6_TABLE_PREFIX RT6_TABLE_MAIN
405
406#ifdef CONFIG_IPV6_MULTIPLE_TABLES
407#define FIB6_TABLE_MIN 1
408#define FIB6_TABLE_MAX RT_TABLE_MAX
409#define RT6_TABLE_LOCAL RT_TABLE_LOCAL
410#else
411#define FIB6_TABLE_MIN RT_TABLE_MAIN
412#define FIB6_TABLE_MAX FIB6_TABLE_MIN
413#define RT6_TABLE_LOCAL RT6_TABLE_MAIN
414#endif
415
416typedef struct rt6_info *(*pol_lookup_t)(struct net *,
417 struct fib6_table *,
418 struct flowi6 *,
419 const struct sk_buff *, int);
420
421struct fib6_entry_notifier_info {
422 struct fib_notifier_info info; /* must be first */
423 struct fib6_info *rt;
424 unsigned int nsiblings;
425};
426
427/*
428 * exported functions
429 */
430
431struct fib6_table *fib6_get_table(struct net *net, u32 id);
432struct fib6_table *fib6_new_table(struct net *net, u32 id);
433struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
434 const struct sk_buff *skb,
435 int flags, pol_lookup_t lookup);
436
437/* called with rcu lock held; can return error pointer
438 * caller needs to select path
439 */
440int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
441 struct fib6_result *res, int flags);
442
443/* called with rcu lock held; caller needs to select path */
444int fib6_table_lookup(struct net *net, struct fib6_table *table,
445 int oif, struct flowi6 *fl6, struct fib6_result *res,
446 int strict);
447
448void fib6_select_path(const struct net *net, struct fib6_result *res,
449 struct flowi6 *fl6, int oif, bool have_oif_match,
450 const struct sk_buff *skb, int strict);
451struct fib6_node *fib6_node_lookup(struct fib6_node *root,
452 const struct in6_addr *daddr,
453 const struct in6_addr *saddr);
454
455struct fib6_node *fib6_locate(struct fib6_node *root,
456 const struct in6_addr *daddr, int dst_len,
457 const struct in6_addr *saddr, int src_len,
458 bool exact_match);
459
460void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
461 void *arg);
462void fib6_clean_all_skip_notify(struct net *net,
463 int (*func)(struct fib6_info *, void *arg),
464 void *arg);
465
466int fib6_add(struct fib6_node *root, struct fib6_info *rt,
467 struct nl_info *info, struct netlink_ext_ack *extack);
468int fib6_del(struct fib6_info *rt, struct nl_info *info);
469
470static inline
471void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
472{
473 const struct fib6_info *from;
474
475 rcu_read_lock();
476
477 from = rcu_dereference(rt->from);
478 if (from)
479 *addr = from->fib6_prefsrc.addr;
480 else
481 *addr = in6addr_any;
482
483 rcu_read_unlock();
484}
485
486int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
487 struct fib6_config *cfg, gfp_t gfp_flags,
488 struct netlink_ext_ack *extack);
489void fib6_nh_release(struct fib6_nh *fib6_nh);
490void fib6_nh_release_dsts(struct fib6_nh *fib6_nh);
491
492int call_fib6_entry_notifiers(struct net *net,
493 enum fib_event_type event_type,
494 struct fib6_info *rt,
495 struct netlink_ext_ack *extack);
496int call_fib6_multipath_entry_notifiers(struct net *net,
497 enum fib_event_type event_type,
498 struct fib6_info *rt,
499 unsigned int nsiblings,
500 struct netlink_ext_ack *extack);
501int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt);
502void fib6_rt_update(struct net *net, struct fib6_info *rt,
503 struct nl_info *info);
504void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
505 unsigned int flags);
506
507void fib6_run_gc(unsigned long expires, struct net *net, bool force);
508
509void fib6_gc_cleanup(void);
510
511int fib6_init(void);
512
513/* Add the route to the gc list if it is not already there
514 *
515 * The callers should hold f6i->fib6_table->tb6_lock.
516 */
517static inline void fib6_add_gc_list(struct fib6_info *f6i)
518{
519 /* If fib6_node is null, the f6i is not in (or removed from) the
520 * table.
521 *
522 * There is a gap between finding the f6i from the table and
523 * calling this function without the protection of the tb6_lock.
524 * This check makes sure the f6i is not added to the gc list when
525 * it is not on the table.
526 */
527 if (!rcu_dereference_protected(f6i->fib6_node,
528 lockdep_is_held(&f6i->fib6_table->tb6_lock)))
529 return;
530
531 if (hlist_unhashed(h: &f6i->gc_link))
532 hlist_add_head(n: &f6i->gc_link, h: &f6i->fib6_table->tb6_gc_hlist);
533}
534
535/* Remove the route from the gc list if it is on the list.
536 *
537 * The callers should hold f6i->fib6_table->tb6_lock.
538 */
539static inline void fib6_remove_gc_list(struct fib6_info *f6i)
540{
541 if (!hlist_unhashed(h: &f6i->gc_link))
542 hlist_del_init(n: &f6i->gc_link);
543}
544
545struct ipv6_route_iter {
546 struct seq_net_private p;
547 struct fib6_walker w;
548 loff_t skip;
549 struct fib6_table *tbl;
550 int sernum;
551};
552
553extern const struct seq_operations ipv6_route_seq_ops;
554
555int call_fib6_notifier(struct notifier_block *nb,
556 enum fib_event_type event_type,
557 struct fib_notifier_info *info);
558int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
559 struct fib_notifier_info *info);
560
561int __net_init fib6_notifier_init(struct net *net);
562void __net_exit fib6_notifier_exit(struct net *net);
563
564unsigned int fib6_tables_seq_read(struct net *net);
565int fib6_tables_dump(struct net *net, struct notifier_block *nb,
566 struct netlink_ext_ack *extack);
567
568void fib6_update_sernum(struct net *net, struct fib6_info *rt);
569void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
570void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
571
572void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
573static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
574{
575 return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
576}
577void fib6_info_hw_flags_set(struct net *net, struct fib6_info *f6i,
578 bool offload, bool trap, bool offload_failed);
579
580#if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
581struct bpf_iter__ipv6_route {
582 __bpf_md_ptr(struct bpf_iter_meta *, meta);
583 __bpf_md_ptr(struct fib6_info *, rt);
584};
585#endif
586
587INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_output(struct net *net,
588 struct fib6_table *table,
589 struct flowi6 *fl6,
590 const struct sk_buff *skb,
591 int flags));
592INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_input(struct net *net,
593 struct fib6_table *table,
594 struct flowi6 *fl6,
595 const struct sk_buff *skb,
596 int flags));
597INDIRECT_CALLABLE_DECLARE(struct rt6_info *__ip6_route_redirect(struct net *net,
598 struct fib6_table *table,
599 struct flowi6 *fl6,
600 const struct sk_buff *skb,
601 int flags));
602INDIRECT_CALLABLE_DECLARE(struct rt6_info *ip6_pol_route_lookup(struct net *net,
603 struct fib6_table *table,
604 struct flowi6 *fl6,
605 const struct sk_buff *skb,
606 int flags));
607static inline struct rt6_info *pol_lookup_func(pol_lookup_t lookup,
608 struct net *net,
609 struct fib6_table *table,
610 struct flowi6 *fl6,
611 const struct sk_buff *skb,
612 int flags)
613{
614 return INDIRECT_CALL_4(lookup,
615 ip6_pol_route_output,
616 ip6_pol_route_input,
617 ip6_pol_route_lookup,
618 __ip6_route_redirect,
619 net, table, fl6, skb, flags);
620}
621
622#ifdef CONFIG_IPV6_MULTIPLE_TABLES
623static inline bool fib6_has_custom_rules(const struct net *net)
624{
625 return net->ipv6.fib6_has_custom_rules;
626}
627
628int fib6_rules_init(void);
629void fib6_rules_cleanup(void);
630bool fib6_rule_default(const struct fib_rule *rule);
631int fib6_rules_dump(struct net *net, struct notifier_block *nb,
632 struct netlink_ext_ack *extack);
633unsigned int fib6_rules_seq_read(struct net *net);
634
635static inline bool fib6_rules_early_flow_dissect(struct net *net,
636 struct sk_buff *skb,
637 struct flowi6 *fl6,
638 struct flow_keys *flkeys)
639{
640 unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
641
642 if (!net->ipv6.fib6_rules_require_fldissect)
643 return false;
644
645 memset(flkeys, 0, sizeof(*flkeys));
646 __skb_flow_dissect(net, skb, flow_dissector: &flow_keys_dissector,
647 target_container: flkeys, NULL, proto: 0, nhoff: 0, hlen: 0, flags: flag);
648
649 fl6->fl6_sport = flkeys->ports.src;
650 fl6->fl6_dport = flkeys->ports.dst;
651 fl6->flowi6_proto = flkeys->basic.ip_proto;
652
653 return true;
654}
655#else
656static inline bool fib6_has_custom_rules(const struct net *net)
657{
658 return false;
659}
660static inline int fib6_rules_init(void)
661{
662 return 0;
663}
664static inline void fib6_rules_cleanup(void)
665{
666 return ;
667}
668static inline bool fib6_rule_default(const struct fib_rule *rule)
669{
670 return true;
671}
672static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb,
673 struct netlink_ext_ack *extack)
674{
675 return 0;
676}
677static inline unsigned int fib6_rules_seq_read(struct net *net)
678{
679 return 0;
680}
681static inline bool fib6_rules_early_flow_dissect(struct net *net,
682 struct sk_buff *skb,
683 struct flowi6 *fl6,
684 struct flow_keys *flkeys)
685{
686 return false;
687}
688#endif
689#endif
690

source code of linux/include/net/ip6_fib.h