xref: /openbmc/linux/include/net/ip6_fib.h (revision 8365a898)
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 
23 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
24 #define FIB6_TABLE_HASHSZ 256
25 #else
26 #define FIB6_TABLE_HASHSZ 1
27 #endif
28 
29 #define RT6_DEBUG 2
30 
31 #if RT6_DEBUG >= 3
32 #define RT6_TRACE(x...) pr_debug(x)
33 #else
34 #define RT6_TRACE(x...) do { ; } while (0)
35 #endif
36 
37 struct rt6_info;
38 struct fib6_info;
39 
40 struct fib6_config {
41 	u32		fc_table;
42 	u32		fc_metric;
43 	int		fc_dst_len;
44 	int		fc_src_len;
45 	int		fc_ifindex;
46 	u32		fc_flags;
47 	u32		fc_protocol;
48 	u16		fc_type;        /* only 8 bits are used */
49 	u16		fc_delete_all_nh : 1,
50 			fc_ignore_dev_down:1,
51 			__unused : 14;
52 	u32		fc_nh_id;
53 
54 	struct in6_addr	fc_dst;
55 	struct in6_addr	fc_src;
56 	struct in6_addr	fc_prefsrc;
57 	struct in6_addr	fc_gateway;
58 
59 	unsigned long	fc_expires;
60 	struct nlattr	*fc_mx;
61 	int		fc_mx_len;
62 	int		fc_mp_len;
63 	struct nlattr	*fc_mp;
64 
65 	struct nl_info	fc_nlinfo;
66 	struct nlattr	*fc_encap;
67 	u16		fc_encap_type;
68 	bool		fc_is_fdb;
69 };
70 
71 struct fib6_node {
72 	struct fib6_node __rcu	*parent;
73 	struct fib6_node __rcu	*left;
74 	struct fib6_node __rcu	*right;
75 #ifdef CONFIG_IPV6_SUBTREES
76 	struct fib6_node __rcu	*subtree;
77 #endif
78 	struct fib6_info __rcu	*leaf;
79 
80 	__u16			fn_bit;		/* bit key */
81 	__u16			fn_flags;
82 	int			fn_sernum;
83 	struct fib6_info __rcu	*rr_ptr;
84 	struct rcu_head		rcu;
85 };
86 
87 struct fib6_gc_args {
88 	int			timeout;
89 	int			more;
90 };
91 
92 #ifndef CONFIG_IPV6_SUBTREES
93 #define FIB6_SUBTREE(fn)	NULL
94 
95 static inline bool fib6_routes_require_src(const struct net *net)
96 {
97 	return false;
98 }
99 
100 static inline void fib6_routes_require_src_inc(struct net *net) {}
101 static inline void fib6_routes_require_src_dec(struct net *net) {}
102 
103 #else
104 
105 static inline bool fib6_routes_require_src(const struct net *net)
106 {
107 	return net->ipv6.fib6_routes_require_src > 0;
108 }
109 
110 static inline void fib6_routes_require_src_inc(struct net *net)
111 {
112 	net->ipv6.fib6_routes_require_src++;
113 }
114 
115 static inline void fib6_routes_require_src_dec(struct net *net)
116 {
117 	net->ipv6.fib6_routes_require_src--;
118 }
119 
120 #define FIB6_SUBTREE(fn)	(rcu_dereference_protected((fn)->subtree, 1))
121 #endif
122 
123 /*
124  *	routing information
125  *
126  */
127 
128 struct rt6key {
129 	struct in6_addr	addr;
130 	int		plen;
131 };
132 
133 struct fib6_table;
134 
135 struct rt6_exception_bucket {
136 	struct hlist_head	chain;
137 	int			depth;
138 };
139 
140 struct rt6_exception {
141 	struct hlist_node	hlist;
142 	struct rt6_info		*rt6i;
143 	unsigned long		stamp;
144 	struct rcu_head		rcu;
145 };
146 
147 #define FIB6_EXCEPTION_BUCKET_SIZE_SHIFT 10
148 #define FIB6_EXCEPTION_BUCKET_SIZE (1 << FIB6_EXCEPTION_BUCKET_SIZE_SHIFT)
149 #define FIB6_MAX_DEPTH 5
150 
151 struct fib6_nh {
152 	struct fib_nh_common	nh_common;
153 
154 #ifdef CONFIG_IPV6_ROUTER_PREF
155 	unsigned long		last_probe;
156 #endif
157 
158 	struct rt6_info * __percpu *rt6i_pcpu;
159 	struct rt6_exception_bucket __rcu *rt6i_exception_bucket;
160 };
161 
162 struct fib6_info {
163 	struct fib6_table		*fib6_table;
164 	struct fib6_info __rcu		*fib6_next;
165 	struct fib6_node __rcu		*fib6_node;
166 
167 	/* Multipath routes:
168 	 * siblings is a list of fib6_info that have the the same metric/weight,
169 	 * destination, but not the same gateway. nsiblings is just a cache
170 	 * to speed up lookup.
171 	 */
172 	union {
173 		struct list_head	fib6_siblings;
174 		struct list_head	nh_list;
175 	};
176 	unsigned int			fib6_nsiblings;
177 
178 	refcount_t			fib6_ref;
179 	unsigned long			expires;
180 	struct dst_metrics		*fib6_metrics;
181 #define fib6_pmtu		fib6_metrics->metrics[RTAX_MTU-1]
182 
183 	struct rt6key			fib6_dst;
184 	u32				fib6_flags;
185 	struct rt6key			fib6_src;
186 	struct rt6key			fib6_prefsrc;
187 
188 	u32				fib6_metric;
189 	u8				fib6_protocol;
190 	u8				fib6_type;
191 	u8				should_flush:1,
192 					dst_nocount:1,
193 					dst_nopolicy:1,
194 					fib6_destroying:1,
195 					offload:1,
196 					trap:1,
197 					unused:2;
198 
199 	struct rcu_head			rcu;
200 	struct nexthop			*nh;
201 	struct fib6_nh			fib6_nh[];
202 };
203 
204 struct rt6_info {
205 	struct dst_entry		dst;
206 	struct fib6_info __rcu		*from;
207 	int				sernum;
208 
209 	struct rt6key			rt6i_dst;
210 	struct rt6key			rt6i_src;
211 	struct in6_addr			rt6i_gateway;
212 	struct inet6_dev		*rt6i_idev;
213 	u32				rt6i_flags;
214 
215 	struct list_head		rt6i_uncached;
216 	struct uncached_list		*rt6i_uncached_list;
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 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
239 {
240 	return ((struct rt6_info *)dst)->rt6i_idev;
241 }
242 
243 static inline bool fib6_requires_src(const struct fib6_info *rt)
244 {
245 	return rt->fib6_src.plen > 0;
246 }
247 
248 static inline void fib6_clean_expires(struct fib6_info *f6i)
249 {
250 	f6i->fib6_flags &= ~RTF_EXPIRES;
251 	f6i->expires = 0;
252 }
253 
254 static inline void fib6_set_expires(struct fib6_info *f6i,
255 				    unsigned long expires)
256 {
257 	f6i->expires = expires;
258 	f6i->fib6_flags |= RTF_EXPIRES;
259 }
260 
261 static inline bool fib6_check_expired(const struct fib6_info *f6i)
262 {
263 	if (f6i->fib6_flags & RTF_EXPIRES)
264 		return time_after(jiffies, f6i->expires);
265 	return false;
266 }
267 
268 /* Function to safely get fn->sernum for passed in rt
269  * and store result in passed in cookie.
270  * Return true if we can get cookie safely
271  * Return false if not
272  */
273 static inline bool fib6_get_cookie_safe(const struct fib6_info *f6i,
274 					u32 *cookie)
275 {
276 	struct fib6_node *fn;
277 	bool status = false;
278 
279 	fn = rcu_dereference(f6i->fib6_node);
280 
281 	if (fn) {
282 		*cookie = fn->fn_sernum;
283 		/* pairs with smp_wmb() in fib6_update_sernum_upto_root() */
284 		smp_rmb();
285 		status = true;
286 	}
287 
288 	return status;
289 }
290 
291 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
292 {
293 	struct fib6_info *from;
294 	u32 cookie = 0;
295 
296 	if (rt->sernum)
297 		return rt->sernum;
298 
299 	rcu_read_lock();
300 
301 	from = rcu_dereference(rt->from);
302 	if (from)
303 		fib6_get_cookie_safe(from, &cookie);
304 
305 	rcu_read_unlock();
306 
307 	return cookie;
308 }
309 
310 static inline void ip6_rt_put(struct rt6_info *rt)
311 {
312 	/* dst_release() accepts a NULL parameter.
313 	 * We rely on dst being first structure in struct rt6_info
314 	 */
315 	BUILD_BUG_ON(offsetof(struct rt6_info, dst) != 0);
316 	dst_release(&rt->dst);
317 }
318 
319 struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh);
320 void fib6_info_destroy_rcu(struct rcu_head *head);
321 
322 static inline void fib6_info_hold(struct fib6_info *f6i)
323 {
324 	refcount_inc(&f6i->fib6_ref);
325 }
326 
327 static inline bool fib6_info_hold_safe(struct fib6_info *f6i)
328 {
329 	return refcount_inc_not_zero(&f6i->fib6_ref);
330 }
331 
332 static inline void fib6_info_release(struct fib6_info *f6i)
333 {
334 	if (f6i && refcount_dec_and_test(&f6i->fib6_ref))
335 		call_rcu(&f6i->rcu, fib6_info_destroy_rcu);
336 }
337 
338 static inline void fib6_info_hw_flags_set(struct fib6_info *f6i, bool offload,
339 					  bool trap)
340 {
341 	f6i->offload = offload;
342 	f6i->trap = trap;
343 }
344 
345 enum 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 
355 struct 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 
367 struct 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 stats are not protected by any lock */
375 	atomic_t	fib_rt_alloc;		/* total number of routes alloced */
376 	atomic_t	fib_rt_uncache;		/* rt entries in uncached list */
377 };
378 
379 #define RTN_TL_ROOT	0x0001
380 #define RTN_ROOT	0x0002		/* tree root node		*/
381 #define RTN_RTINFO	0x0004		/* node with valid routing info	*/
382 
383 /*
384  *	priority levels (or metrics)
385  *
386  */
387 
388 
389 struct fib6_table {
390 	struct hlist_node	tb6_hlist;
391 	u32			tb6_id;
392 	spinlock_t		tb6_lock;
393 	struct fib6_node	tb6_root;
394 	struct inet_peer_base	tb6_peers;
395 	unsigned int		flags;
396 	unsigned int		fib_seq;
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 
416 typedef struct rt6_info *(*pol_lookup_t)(struct net *,
417 					 struct fib6_table *,
418 					 struct flowi6 *,
419 					 const struct sk_buff *, int);
420 
421 struct 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 
431 struct fib6_table *fib6_get_table(struct net *net, u32 id);
432 struct fib6_table *fib6_new_table(struct net *net, u32 id);
433 struct 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  */
440 int 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 */
444 int fib6_table_lookup(struct net *net, struct fib6_table *table,
445 		      int oif, struct flowi6 *fl6, struct fib6_result *res,
446 		      int strict);
447 
448 void 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);
451 struct fib6_node *fib6_node_lookup(struct fib6_node *root,
452 				   const struct in6_addr *daddr,
453 				   const struct in6_addr *saddr);
454 
455 struct 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 
460 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *arg),
461 		    void *arg);
462 void fib6_clean_all_skip_notify(struct net *net,
463 				int (*func)(struct fib6_info *, void *arg),
464 				void *arg);
465 
466 int fib6_add(struct fib6_node *root, struct fib6_info *rt,
467 	     struct nl_info *info, struct netlink_ext_ack *extack);
468 int fib6_del(struct fib6_info *rt, struct nl_info *info);
469 
470 static inline
471 void 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 		struct in6_addr in6_zero = {};
482 
483 		*addr = in6_zero;
484 	}
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 
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 struct ipv6_route_iter {
516 	struct seq_net_private p;
517 	struct fib6_walker w;
518 	loff_t skip;
519 	struct fib6_table *tbl;
520 	int sernum;
521 };
522 
523 extern const struct seq_operations ipv6_route_seq_ops;
524 
525 int call_fib6_notifier(struct notifier_block *nb,
526 		       enum fib_event_type event_type,
527 		       struct fib_notifier_info *info);
528 int call_fib6_notifiers(struct net *net, enum fib_event_type event_type,
529 			struct fib_notifier_info *info);
530 
531 int __net_init fib6_notifier_init(struct net *net);
532 void __net_exit fib6_notifier_exit(struct net *net);
533 
534 unsigned int fib6_tables_seq_read(struct net *net);
535 int fib6_tables_dump(struct net *net, struct notifier_block *nb,
536 		     struct netlink_ext_ack *extack);
537 
538 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
539 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
540 void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
541 
542 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
543 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
544 {
545 	return !!(f6i->fib6_metrics->metrics[RTAX_LOCK - 1] & (1 << metric));
546 }
547 
548 #if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
549 struct bpf_iter__ipv6_route {
550 	__bpf_md_ptr(struct bpf_iter_meta *, meta);
551 	__bpf_md_ptr(struct fib6_info *, rt);
552 };
553 #endif
554 
555 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
556 static inline bool fib6_has_custom_rules(const struct net *net)
557 {
558 	return net->ipv6.fib6_has_custom_rules;
559 }
560 
561 int fib6_rules_init(void);
562 void fib6_rules_cleanup(void);
563 bool fib6_rule_default(const struct fib_rule *rule);
564 int fib6_rules_dump(struct net *net, struct notifier_block *nb,
565 		    struct netlink_ext_ack *extack);
566 unsigned int fib6_rules_seq_read(struct net *net);
567 
568 static inline bool fib6_rules_early_flow_dissect(struct net *net,
569 						 struct sk_buff *skb,
570 						 struct flowi6 *fl6,
571 						 struct flow_keys *flkeys)
572 {
573 	unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
574 
575 	if (!net->ipv6.fib6_rules_require_fldissect)
576 		return false;
577 
578 	skb_flow_dissect_flow_keys(skb, flkeys, flag);
579 	fl6->fl6_sport = flkeys->ports.src;
580 	fl6->fl6_dport = flkeys->ports.dst;
581 	fl6->flowi6_proto = flkeys->basic.ip_proto;
582 
583 	return true;
584 }
585 #else
586 static inline bool fib6_has_custom_rules(const struct net *net)
587 {
588 	return false;
589 }
590 static inline int               fib6_rules_init(void)
591 {
592 	return 0;
593 }
594 static inline void              fib6_rules_cleanup(void)
595 {
596 	return ;
597 }
598 static inline bool fib6_rule_default(const struct fib_rule *rule)
599 {
600 	return true;
601 }
602 static inline int fib6_rules_dump(struct net *net, struct notifier_block *nb,
603 				  struct netlink_ext_ack *extack)
604 {
605 	return 0;
606 }
607 static inline unsigned int fib6_rules_seq_read(struct net *net)
608 {
609 	return 0;
610 }
611 static inline bool fib6_rules_early_flow_dissect(struct net *net,
612 						 struct sk_buff *skb,
613 						 struct flowi6 *fl6,
614 						 struct flow_keys *flkeys)
615 {
616 	return false;
617 }
618 #endif
619 #endif
620