nexthop.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * Generic nexthop implementation
  4 *
  5 * Copyright (c) 2017-19 Cumulus Networks
  6 * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
  7 */
  8
  9#ifndef __LINUX_NEXTHOP_H
 10#define __LINUX_NEXTHOP_H
 11
 12#include <linux/netdevice.h>
 13#include <linux/notifier.h>
 14#include <linux/route.h>
 15#include <linux/types.h>
 16#include <net/ip_fib.h>
 17#include <net/ip6_fib.h>
 18#include <net/netlink.h>
 19
 20#define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
 21
 22struct nexthop;
 23
 24struct nh_config {
 25	u32		nh_id;
 26
 27	u8		nh_family;
 28	u8		nh_protocol;
 29	u8		nh_blackhole;
 30	u8		nh_fdb;
 31	u32		nh_flags;
 32
 33	int		nh_ifindex;
 34	struct net_device *dev;
 35
 36	union {
 37		__be32		ipv4;
 38		struct in6_addr	ipv6;
 39	} gw;
 40
 41	struct nlattr	*nh_grp;
 42	u16		nh_grp_type;
 43	u16		nh_grp_res_num_buckets;
 44	unsigned long	nh_grp_res_idle_timer;
 45	unsigned long	nh_grp_res_unbalanced_timer;
 46	bool		nh_grp_res_has_num_buckets;
 47	bool		nh_grp_res_has_idle_timer;
 48	bool		nh_grp_res_has_unbalanced_timer;
 49
 50	bool		nh_hw_stats;
 51
 52	struct nlattr	*nh_encap;
 53	u16		nh_encap_type;
 54
 55	u32		nlflags;
 56	struct nl_info	nlinfo;
 57};
 58
 59struct nh_info {
 60	struct hlist_node	dev_hash;    /* entry on netns devhash */
 61	struct nexthop		*nh_parent;
 62
 63	u8			family;
 64	bool			reject_nh;
 65	bool			fdb_nh;
 66
 67	union {
 68		struct fib_nh_common	fib_nhc;
 69		struct fib_nh		fib_nh;
 70		struct fib6_nh		fib6_nh;
 71	};
 72};
 73
 74struct nh_res_bucket {
 75	struct nh_grp_entry __rcu *nh_entry;
 76	atomic_long_t		used_time;
 77	unsigned long		migrated_time;
 78	bool			occupied;
 79	u8			nh_flags;
 80};
 81
 82struct nh_res_table {
 83	struct net		*net;
 84	u32			nhg_id;
 85	struct delayed_work	upkeep_dw;
 86
 87	/* List of NHGEs that have too few buckets ("uw" for underweight).
 88	 * Reclaimed buckets will be given to entries in this list.
 89	 */
 90	struct list_head	uw_nh_entries;
 91	unsigned long		unbalanced_since;
 92
 93	u32			idle_timer;
 94	u32			unbalanced_timer;
 95
 96	u16			num_nh_buckets;
 97	struct nh_res_bucket	nh_buckets[] __counted_by(num_nh_buckets);
 98};
 99
100struct nh_grp_entry_stats {
101	u64_stats_t packets;
102	struct u64_stats_sync syncp;
103};
104
105struct nh_grp_entry {
106	struct nexthop	*nh;
107	struct nh_grp_entry_stats __percpu	*stats;
108	u16		weight;
109
110	union {
111		struct {
112			atomic_t	upper_bound;
113		} hthr;
114		struct {
115			/* Member on uw_nh_entries. */
116			struct list_head	uw_nh_entry;
117
118			u16			count_buckets;
119			u16			wants_buckets;
120		} res;
121	};
122
123	struct list_head nh_list;
124	struct nexthop	*nh_parent;  /* nexthop of group with this entry */
125	u64		packets_hw;
126};
127
128struct nh_group {
129	struct nh_group		*spare; /* spare group for removals */
130	u16			num_nh;
131	bool			is_multipath;
132	bool			hash_threshold;
133	bool			resilient;
134	bool			fdb_nh;
135	bool			has_v4;
136	bool			hw_stats;
137
138	struct nh_res_table __rcu *res_table;
139	struct nh_grp_entry	nh_entries[] __counted_by(num_nh);
140};
141
142struct nexthop {
143	struct rb_node		rb_node;    /* entry on netns rbtree */
144	struct list_head	fi_list;    /* v4 entries using nh */
145	struct list_head	f6i_list;   /* v6 entries using nh */
146	struct list_head        fdb_list;   /* fdb entries using this nh */
147	struct list_head	grp_list;   /* nh group entries using this nh */
148	struct net		*net;
149
150	u32			id;
151
152	u8			protocol;   /* app managing this nh */
153	u8			nh_flags;
154	bool			is_group;
155	bool			dead;
156	spinlock_t		lock;       /* protect dead and f6i_list */
157
158	refcount_t		refcnt;
159	struct rcu_head		rcu;
160
161	union {
162		struct nh_info	__rcu *nh_info;
163		struct nh_group __rcu *nh_grp;
164	};
165};
166
167enum nexthop_event_type {
168	NEXTHOP_EVENT_DEL,
169	NEXTHOP_EVENT_REPLACE,
170	NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
171	NEXTHOP_EVENT_BUCKET_REPLACE,
172	NEXTHOP_EVENT_HW_STATS_REPORT_DELTA,
173};
174
175enum nh_notifier_info_type {
176	NH_NOTIFIER_INFO_TYPE_SINGLE,
177	NH_NOTIFIER_INFO_TYPE_GRP,
178	NH_NOTIFIER_INFO_TYPE_RES_TABLE,
179	NH_NOTIFIER_INFO_TYPE_RES_BUCKET,
180	NH_NOTIFIER_INFO_TYPE_GRP_HW_STATS,
181};
182
183struct nh_notifier_single_info {
184	struct net_device *dev;
185	u8 gw_family;
186	union {
187		__be32 ipv4;
188		struct in6_addr ipv6;
189	};
190	u32 id;
191	u8 is_reject:1,
192	   is_fdb:1,
193	   has_encap:1;
194};
195
196struct nh_notifier_grp_entry_info {
197	u16 weight;
198	struct nh_notifier_single_info nh;
199};
200
201struct nh_notifier_grp_info {
202	u16 num_nh;
203	bool is_fdb;
204	bool hw_stats;
205	struct nh_notifier_grp_entry_info nh_entries[] __counted_by(num_nh);
206};
207
208struct nh_notifier_res_bucket_info {
209	u16 bucket_index;
210	unsigned int idle_timer_ms;
211	bool force;
212	struct nh_notifier_single_info old_nh;
213	struct nh_notifier_single_info new_nh;
214};
215
216struct nh_notifier_res_table_info {
217	u16 num_nh_buckets;
218	bool hw_stats;
219	struct nh_notifier_single_info nhs[] __counted_by(num_nh_buckets);
220};
221
222struct nh_notifier_grp_hw_stats_entry_info {
223	u32 id;
224	u64 packets;
225};
226
227struct nh_notifier_grp_hw_stats_info {
228	u16 num_nh;
229	bool hw_stats_used;
230	struct nh_notifier_grp_hw_stats_entry_info stats[] __counted_by(num_nh);
231};
232
233struct nh_notifier_info {
234	struct net *net;
235	struct netlink_ext_ack *extack;
236	u32 id;
237	enum nh_notifier_info_type type;
238	union {
239		struct nh_notifier_single_info *nh;
240		struct nh_notifier_grp_info *nh_grp;
241		struct nh_notifier_res_table_info *nh_res_table;
242		struct nh_notifier_res_bucket_info *nh_res_bucket;
243		struct nh_notifier_grp_hw_stats_info *nh_grp_hw_stats;
244	};
245};
246
247int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
248			      struct netlink_ext_ack *extack);
249int __unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
250int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
251void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
252void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
253				 bool offload, bool trap);
254void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
255				     unsigned long *activity);
256void nh_grp_hw_stats_report_delta(struct nh_notifier_grp_hw_stats_info *info,
257				  unsigned int nh_idx,
258				  u64 delta_packets);
259
260/* caller is holding rcu or rtnl; no reference taken to nexthop */
261struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
262void nexthop_free_rcu(struct rcu_head *head);
263
264static inline bool nexthop_get(struct nexthop *nh)
265{
266	return refcount_inc_not_zero(&nh->refcnt);
267}
268
269static inline void nexthop_put(struct nexthop *nh)
270{
271	if (refcount_dec_and_test(&nh->refcnt))
272		call_rcu_hurry(&nh->rcu, nexthop_free_rcu);
273}
274
275static inline bool nexthop_cmp(const struct nexthop *nh1,
276			       const struct nexthop *nh2)
277{
278	return nh1 == nh2;
279}
280
281static inline bool nexthop_is_fdb(const struct nexthop *nh)
282{
283	if (nh->is_group) {
284		const struct nh_group *nh_grp;
285
286		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
287		return nh_grp->fdb_nh;
288	} else {
289		const struct nh_info *nhi;
290
291		nhi = rcu_dereference_rtnl(nh->nh_info);
292		return nhi->fdb_nh;
293	}
294}
295
296static inline bool nexthop_has_v4(const struct nexthop *nh)
297{
298	if (nh->is_group) {
299		struct nh_group *nh_grp;
300
301		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
302		return nh_grp->has_v4;
303	}
304	return false;
305}
306
307static inline bool nexthop_is_multipath(const struct nexthop *nh)
308{
309	if (nh->is_group) {
310		struct nh_group *nh_grp;
311
312		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
313		return nh_grp->is_multipath;
314	}
315	return false;
316}
317
318struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
319
320static inline unsigned int nexthop_num_path(const struct nexthop *nh)
321{
322	unsigned int rc = 1;
323
324	if (nh->is_group) {
325		struct nh_group *nh_grp;
326
327		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
328		if (nh_grp->is_multipath)
329			rc = nh_grp->num_nh;
330	}
331
332	return rc;
333}
334
335static inline
336struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
337{
338	/* for_nexthops macros in fib_semantics.c grabs a pointer to
339	 * the nexthop before checking nhsel
340	 */
341	if (nhsel >= nhg->num_nh)
342		return NULL;
343
344	return nhg->nh_entries[nhsel].nh;
345}
346
347static inline
348int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
349			    u8 rt_family)
350{
351	struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
352	int i;
353
354	for (i = 0; i < nhg->num_nh; i++) {
355		struct nexthop *nhe = nhg->nh_entries[i].nh;
356		struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
357		struct fib_nh_common *nhc = &nhi->fib_nhc;
358		int weight = nhg->nh_entries[i].weight;
359
360		if (fib_add_nexthop(skb, nhc, weight, rt_family, 0) < 0)
361			return -EMSGSIZE;
362	}
363
364	return 0;
365}
366
367/* called with rcu lock */
368static inline bool nexthop_is_blackhole(const struct nexthop *nh)
369{
370	const struct nh_info *nhi;
371
372	if (nh->is_group) {
373		struct nh_group *nh_grp;
374
375		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
376		if (nh_grp->num_nh > 1)
377			return false;
378
379		nh = nh_grp->nh_entries[0].nh;
380	}
381
382	nhi = rcu_dereference_rtnl(nh->nh_info);
383	return nhi->reject_nh;
384}
385
386static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
387{
388	struct nh_info *nhi;
389	struct nexthop *nh;
390
391	nh = nexthop_select_path(res->fi->nh, hash);
392	nhi = rcu_dereference(nh->nh_info);
393	res->nhc = &nhi->fib_nhc;
394}
395
396/* called with rcu read lock or rtnl held */
397static inline
398struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
399{
400	struct nh_info *nhi;
401
402	BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
403	BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
404
405	if (nh->is_group) {
406		struct nh_group *nh_grp;
407
408		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
409		if (nh_grp->is_multipath) {
410			nh = nexthop_mpath_select(nh_grp, nhsel);
411			if (!nh)
412				return NULL;
413		}
414	}
415
416	nhi = rcu_dereference_rtnl(nh->nh_info);
417	return &nhi->fib_nhc;
418}
419
420/* called from fib_table_lookup with rcu_lock */
421static inline
422struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
423					     int fib_flags,
424					     const struct flowi4 *flp,
425					     int *nhsel)
426{
427	struct nh_info *nhi;
428
429	if (nh->is_group) {
430		struct nh_group *nhg = rcu_dereference(nh->nh_grp);
431		int i;
432
433		for (i = 0; i < nhg->num_nh; i++) {
434			struct nexthop *nhe = nhg->nh_entries[i].nh;
435
436			nhi = rcu_dereference(nhe->nh_info);
437			if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
438				*nhsel = i;
439				return &nhi->fib_nhc;
440			}
441		}
442	} else {
443		nhi = rcu_dereference(nh->nh_info);
444		if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
445			*nhsel = 0;
446			return &nhi->fib_nhc;
447		}
448	}
449
450	return NULL;
451}
452
453static inline bool nexthop_uses_dev(const struct nexthop *nh,
454				    const struct net_device *dev)
455{
456	struct nh_info *nhi;
457
458	if (nh->is_group) {
459		struct nh_group *nhg = rcu_dereference(nh->nh_grp);
460		int i;
461
462		for (i = 0; i < nhg->num_nh; i++) {
463			struct nexthop *nhe = nhg->nh_entries[i].nh;
464
465			nhi = rcu_dereference(nhe->nh_info);
466			if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
467				return true;
468		}
469	} else {
470		nhi = rcu_dereference(nh->nh_info);
471		if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
472			return true;
473	}
474
475	return false;
476}
477
478static inline unsigned int fib_info_num_path(const struct fib_info *fi)
479{
480	if (unlikely(fi->nh))
481		return nexthop_num_path(fi->nh);
482
483	return fi->fib_nhs;
484}
485
486int fib_check_nexthop(struct nexthop *nh, u8 scope,
487		      struct netlink_ext_ack *extack);
488
489static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
490{
491	if (unlikely(fi->nh))
492		return nexthop_fib_nhc(fi->nh, nhsel);
493
494	return &fi->fib_nh[nhsel].nh_common;
495}
496
497/* only used when fib_nh is built into fib_info */
498static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
499{
500	WARN_ON(fi->nh);
501
502	return &fi->fib_nh[nhsel];
503}
504
505/*
506 * IPv6 variants
507 */
508int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
509		       struct netlink_ext_ack *extack);
510
511/* Caller should either hold rcu_read_lock(), or RTNL. */
512static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
513{
514	struct nh_info *nhi;
515
516	if (nh->is_group) {
517		struct nh_group *nh_grp;
518
519		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
520		nh = nexthop_mpath_select(nh_grp, 0);
521		if (!nh)
522			return NULL;
523	}
524
525	nhi = rcu_dereference_rtnl(nh->nh_info);
526	if (nhi->family == AF_INET6)
527		return &nhi->fib6_nh;
528
529	return NULL;
530}
531
532static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
533{
534	struct fib6_nh *fib6_nh;
535
536	fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
537	return fib6_nh->fib_nh_dev;
538}
539
540static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
541{
542	struct nexthop *nh = res->f6i->nh;
543	struct nh_info *nhi;
544
545	nh = nexthop_select_path(nh, hash);
546
547	nhi = rcu_dereference_rtnl(nh->nh_info);
548	if (nhi->reject_nh) {
549		res->fib6_type = RTN_BLACKHOLE;
550		res->fib6_flags |= RTF_REJECT;
551		res->nh = nexthop_fib6_nh(nh);
552	} else {
553		res->nh = &nhi->fib6_nh;
554	}
555}
556
557int nexthop_for_each_fib6_nh(struct nexthop *nh,
558			     int (*cb)(struct fib6_nh *nh, void *arg),
559			     void *arg);
560
561static inline int nexthop_get_family(struct nexthop *nh)
562{
563	struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
564
565	return nhi->family;
566}
567
568static inline
569struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
570{
571	struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
572
573	return &nhi->fib_nhc;
574}
575
576static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
577							    int hash)
578{
579	struct nh_info *nhi;
580	struct nexthop *nhp;
581
582	nhp = nexthop_select_path(nh, hash);
583	if (unlikely(!nhp))
584		return NULL;
585	nhi = rcu_dereference(nhp->nh_info);
586	return &nhi->fib_nhc;
587}
588#endif