xref: /openbmc/linux/include/net/nexthop.h (revision ef1148d4)
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 
22 struct nexthop;
23 
24 struct 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 	struct nlattr	*nh_encap;
51 	u16		nh_encap_type;
52 
53 	u32		nlflags;
54 	struct nl_info	nlinfo;
55 };
56 
57 struct nh_info {
58 	struct hlist_node	dev_hash;    /* entry on netns devhash */
59 	struct nexthop		*nh_parent;
60 
61 	u8			family;
62 	bool			reject_nh;
63 	bool			fdb_nh;
64 
65 	union {
66 		struct fib_nh_common	fib_nhc;
67 		struct fib_nh		fib_nh;
68 		struct fib6_nh		fib6_nh;
69 	};
70 };
71 
72 struct nh_res_bucket {
73 	struct nh_grp_entry __rcu *nh_entry;
74 	atomic_long_t		used_time;
75 	unsigned long		migrated_time;
76 	bool			occupied;
77 	u8			nh_flags;
78 };
79 
80 struct nh_res_table {
81 	struct net		*net;
82 	u32			nhg_id;
83 	struct delayed_work	upkeep_dw;
84 
85 	/* List of NHGEs that have too few buckets ("uw" for underweight).
86 	 * Reclaimed buckets will be given to entries in this list.
87 	 */
88 	struct list_head	uw_nh_entries;
89 	unsigned long		unbalanced_since;
90 
91 	u32			idle_timer;
92 	u32			unbalanced_timer;
93 
94 	u16			num_nh_buckets;
95 	struct nh_res_bucket	nh_buckets[];
96 };
97 
98 struct nh_grp_entry {
99 	struct nexthop	*nh;
100 	u8		weight;
101 
102 	union {
103 		struct {
104 			atomic_t	upper_bound;
105 		} hthr;
106 		struct {
107 			/* Member on uw_nh_entries. */
108 			struct list_head	uw_nh_entry;
109 
110 			u16			count_buckets;
111 			u16			wants_buckets;
112 		} res;
113 	};
114 
115 	struct list_head nh_list;
116 	struct nexthop	*nh_parent;  /* nexthop of group with this entry */
117 };
118 
119 struct nh_group {
120 	struct nh_group		*spare; /* spare group for removals */
121 	u16			num_nh;
122 	bool			is_multipath;
123 	bool			hash_threshold;
124 	bool			resilient;
125 	bool			fdb_nh;
126 	bool			has_v4;
127 
128 	struct nh_res_table __rcu *res_table;
129 	struct nh_grp_entry	nh_entries[];
130 };
131 
132 struct nexthop {
133 	struct rb_node		rb_node;    /* entry on netns rbtree */
134 	struct list_head	fi_list;    /* v4 entries using nh */
135 	struct list_head	f6i_list;   /* v6 entries using nh */
136 	struct list_head        fdb_list;   /* fdb entries using this nh */
137 	struct list_head	grp_list;   /* nh group entries using this nh */
138 	struct net		*net;
139 
140 	u32			id;
141 
142 	u8			protocol;   /* app managing this nh */
143 	u8			nh_flags;
144 	bool			is_group;
145 
146 	refcount_t		refcnt;
147 	struct rcu_head		rcu;
148 
149 	union {
150 		struct nh_info	__rcu *nh_info;
151 		struct nh_group __rcu *nh_grp;
152 	};
153 };
154 
155 enum nexthop_event_type {
156 	NEXTHOP_EVENT_DEL,
157 	NEXTHOP_EVENT_REPLACE,
158 	NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
159 	NEXTHOP_EVENT_BUCKET_REPLACE,
160 };
161 
162 enum nh_notifier_info_type {
163 	NH_NOTIFIER_INFO_TYPE_SINGLE,
164 	NH_NOTIFIER_INFO_TYPE_GRP,
165 	NH_NOTIFIER_INFO_TYPE_RES_TABLE,
166 	NH_NOTIFIER_INFO_TYPE_RES_BUCKET,
167 };
168 
169 struct nh_notifier_single_info {
170 	struct net_device *dev;
171 	u8 gw_family;
172 	union {
173 		__be32 ipv4;
174 		struct in6_addr ipv6;
175 	};
176 	u8 is_reject:1,
177 	   is_fdb:1,
178 	   has_encap:1;
179 };
180 
181 struct nh_notifier_grp_entry_info {
182 	u8 weight;
183 	u32 id;
184 	struct nh_notifier_single_info nh;
185 };
186 
187 struct nh_notifier_grp_info {
188 	u16 num_nh;
189 	bool is_fdb;
190 	struct nh_notifier_grp_entry_info nh_entries[];
191 };
192 
193 struct nh_notifier_res_bucket_info {
194 	u16 bucket_index;
195 	unsigned int idle_timer_ms;
196 	bool force;
197 	struct nh_notifier_single_info old_nh;
198 	struct nh_notifier_single_info new_nh;
199 };
200 
201 struct nh_notifier_res_table_info {
202 	u16 num_nh_buckets;
203 	struct nh_notifier_single_info nhs[];
204 };
205 
206 struct nh_notifier_info {
207 	struct net *net;
208 	struct netlink_ext_ack *extack;
209 	u32 id;
210 	enum nh_notifier_info_type type;
211 	union {
212 		struct nh_notifier_single_info *nh;
213 		struct nh_notifier_grp_info *nh_grp;
214 		struct nh_notifier_res_table_info *nh_res_table;
215 		struct nh_notifier_res_bucket_info *nh_res_bucket;
216 	};
217 };
218 
219 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
220 			      struct netlink_ext_ack *extack);
221 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
222 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
223 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
224 				 bool offload, bool trap);
225 void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
226 				     unsigned long *activity);
227 
228 /* caller is holding rcu or rtnl; no reference taken to nexthop */
229 struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
230 void nexthop_free_rcu(struct rcu_head *head);
231 
nexthop_get(struct nexthop * nh)232 static inline bool nexthop_get(struct nexthop *nh)
233 {
234 	return refcount_inc_not_zero(&nh->refcnt);
235 }
236 
nexthop_put(struct nexthop * nh)237 static inline void nexthop_put(struct nexthop *nh)
238 {
239 	if (refcount_dec_and_test(&nh->refcnt))
240 		call_rcu(&nh->rcu, nexthop_free_rcu);
241 }
242 
nexthop_cmp(const struct nexthop * nh1,const struct nexthop * nh2)243 static inline bool nexthop_cmp(const struct nexthop *nh1,
244 			       const struct nexthop *nh2)
245 {
246 	return nh1 == nh2;
247 }
248 
nexthop_is_fdb(const struct nexthop * nh)249 static inline bool nexthop_is_fdb(const struct nexthop *nh)
250 {
251 	if (nh->is_group) {
252 		const struct nh_group *nh_grp;
253 
254 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
255 		return nh_grp->fdb_nh;
256 	} else {
257 		const struct nh_info *nhi;
258 
259 		nhi = rcu_dereference_rtnl(nh->nh_info);
260 		return nhi->fdb_nh;
261 	}
262 }
263 
nexthop_has_v4(const struct nexthop * nh)264 static inline bool nexthop_has_v4(const struct nexthop *nh)
265 {
266 	if (nh->is_group) {
267 		struct nh_group *nh_grp;
268 
269 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
270 		return nh_grp->has_v4;
271 	}
272 	return false;
273 }
274 
nexthop_is_multipath(const struct nexthop * nh)275 static inline bool nexthop_is_multipath(const struct nexthop *nh)
276 {
277 	if (nh->is_group) {
278 		struct nh_group *nh_grp;
279 
280 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
281 		return nh_grp->is_multipath;
282 	}
283 	return false;
284 }
285 
286 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
287 
nexthop_num_path(const struct nexthop * nh)288 static inline unsigned int nexthop_num_path(const struct nexthop *nh)
289 {
290 	unsigned int rc = 1;
291 
292 	if (nh->is_group) {
293 		struct nh_group *nh_grp;
294 
295 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
296 		if (nh_grp->is_multipath)
297 			rc = nh_grp->num_nh;
298 	}
299 
300 	return rc;
301 }
302 
303 static inline
nexthop_mpath_select(const struct nh_group * nhg,int nhsel)304 struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
305 {
306 	/* for_nexthops macros in fib_semantics.c grabs a pointer to
307 	 * the nexthop before checking nhsel
308 	 */
309 	if (nhsel >= nhg->num_nh)
310 		return NULL;
311 
312 	return nhg->nh_entries[nhsel].nh;
313 }
314 
315 static inline
nexthop_mpath_fill_node(struct sk_buff * skb,struct nexthop * nh,u8 rt_family)316 int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
317 			    u8 rt_family)
318 {
319 	struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
320 	int i;
321 
322 	for (i = 0; i < nhg->num_nh; i++) {
323 		struct nexthop *nhe = nhg->nh_entries[i].nh;
324 		struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
325 		struct fib_nh_common *nhc = &nhi->fib_nhc;
326 		int weight = nhg->nh_entries[i].weight;
327 
328 		if (fib_add_nexthop(skb, nhc, weight, rt_family, 0) < 0)
329 			return -EMSGSIZE;
330 	}
331 
332 	return 0;
333 }
334 
335 /* called with rcu lock */
nexthop_is_blackhole(const struct nexthop * nh)336 static inline bool nexthop_is_blackhole(const struct nexthop *nh)
337 {
338 	const struct nh_info *nhi;
339 
340 	if (nh->is_group) {
341 		struct nh_group *nh_grp;
342 
343 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
344 		if (nh_grp->num_nh > 1)
345 			return false;
346 
347 		nh = nh_grp->nh_entries[0].nh;
348 	}
349 
350 	nhi = rcu_dereference_rtnl(nh->nh_info);
351 	return nhi->reject_nh;
352 }
353 
nexthop_path_fib_result(struct fib_result * res,int hash)354 static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
355 {
356 	struct nh_info *nhi;
357 	struct nexthop *nh;
358 
359 	nh = nexthop_select_path(res->fi->nh, hash);
360 	nhi = rcu_dereference(nh->nh_info);
361 	res->nhc = &nhi->fib_nhc;
362 }
363 
364 /* called with rcu read lock or rtnl held */
365 static inline
nexthop_fib_nhc(struct nexthop * nh,int nhsel)366 struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
367 {
368 	struct nh_info *nhi;
369 
370 	BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
371 	BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
372 
373 	if (nh->is_group) {
374 		struct nh_group *nh_grp;
375 
376 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
377 		if (nh_grp->is_multipath) {
378 			nh = nexthop_mpath_select(nh_grp, nhsel);
379 			if (!nh)
380 				return NULL;
381 		}
382 	}
383 
384 	nhi = rcu_dereference_rtnl(nh->nh_info);
385 	return &nhi->fib_nhc;
386 }
387 
388 /* called from fib_table_lookup with rcu_lock */
389 static inline
nexthop_get_nhc_lookup(const struct nexthop * nh,int fib_flags,const struct flowi4 * flp,int * nhsel)390 struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
391 					     int fib_flags,
392 					     const struct flowi4 *flp,
393 					     int *nhsel)
394 {
395 	struct nh_info *nhi;
396 
397 	if (nh->is_group) {
398 		struct nh_group *nhg = rcu_dereference(nh->nh_grp);
399 		int i;
400 
401 		for (i = 0; i < nhg->num_nh; i++) {
402 			struct nexthop *nhe = nhg->nh_entries[i].nh;
403 
404 			nhi = rcu_dereference(nhe->nh_info);
405 			if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
406 				*nhsel = i;
407 				return &nhi->fib_nhc;
408 			}
409 		}
410 	} else {
411 		nhi = rcu_dereference(nh->nh_info);
412 		if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
413 			*nhsel = 0;
414 			return &nhi->fib_nhc;
415 		}
416 	}
417 
418 	return NULL;
419 }
420 
nexthop_uses_dev(const struct nexthop * nh,const struct net_device * dev)421 static inline bool nexthop_uses_dev(const struct nexthop *nh,
422 				    const struct net_device *dev)
423 {
424 	struct nh_info *nhi;
425 
426 	if (nh->is_group) {
427 		struct nh_group *nhg = rcu_dereference(nh->nh_grp);
428 		int i;
429 
430 		for (i = 0; i < nhg->num_nh; i++) {
431 			struct nexthop *nhe = nhg->nh_entries[i].nh;
432 
433 			nhi = rcu_dereference(nhe->nh_info);
434 			if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
435 				return true;
436 		}
437 	} else {
438 		nhi = rcu_dereference(nh->nh_info);
439 		if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
440 			return true;
441 	}
442 
443 	return false;
444 }
445 
fib_info_num_path(const struct fib_info * fi)446 static inline unsigned int fib_info_num_path(const struct fib_info *fi)
447 {
448 	if (unlikely(fi->nh))
449 		return nexthop_num_path(fi->nh);
450 
451 	return fi->fib_nhs;
452 }
453 
454 int fib_check_nexthop(struct nexthop *nh, u8 scope,
455 		      struct netlink_ext_ack *extack);
456 
fib_info_nhc(struct fib_info * fi,int nhsel)457 static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
458 {
459 	if (unlikely(fi->nh))
460 		return nexthop_fib_nhc(fi->nh, nhsel);
461 
462 	return &fi->fib_nh[nhsel].nh_common;
463 }
464 
465 /* only used when fib_nh is built into fib_info */
fib_info_nh(struct fib_info * fi,int nhsel)466 static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
467 {
468 	WARN_ON(fi->nh);
469 
470 	return &fi->fib_nh[nhsel];
471 }
472 
473 /*
474  * IPv6 variants
475  */
476 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
477 		       struct netlink_ext_ack *extack);
478 
479 /* Caller should either hold rcu_read_lock(), or RTNL. */
nexthop_fib6_nh(struct nexthop * nh)480 static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
481 {
482 	struct nh_info *nhi;
483 
484 	if (nh->is_group) {
485 		struct nh_group *nh_grp;
486 
487 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
488 		nh = nexthop_mpath_select(nh_grp, 0);
489 		if (!nh)
490 			return NULL;
491 	}
492 
493 	nhi = rcu_dereference_rtnl(nh->nh_info);
494 	if (nhi->family == AF_INET6)
495 		return &nhi->fib6_nh;
496 
497 	return NULL;
498 }
499 
fib6_info_nh_dev(struct fib6_info * f6i)500 static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
501 {
502 	struct fib6_nh *fib6_nh;
503 
504 	fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
505 	return fib6_nh->fib_nh_dev;
506 }
507 
nexthop_path_fib6_result(struct fib6_result * res,int hash)508 static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
509 {
510 	struct nexthop *nh = res->f6i->nh;
511 	struct nh_info *nhi;
512 
513 	nh = nexthop_select_path(nh, hash);
514 
515 	nhi = rcu_dereference_rtnl(nh->nh_info);
516 	if (nhi->reject_nh) {
517 		res->fib6_type = RTN_BLACKHOLE;
518 		res->fib6_flags |= RTF_REJECT;
519 		res->nh = nexthop_fib6_nh(nh);
520 	} else {
521 		res->nh = &nhi->fib6_nh;
522 	}
523 }
524 
525 int nexthop_for_each_fib6_nh(struct nexthop *nh,
526 			     int (*cb)(struct fib6_nh *nh, void *arg),
527 			     void *arg);
528 
nexthop_get_family(struct nexthop * nh)529 static inline int nexthop_get_family(struct nexthop *nh)
530 {
531 	struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
532 
533 	return nhi->family;
534 }
535 
536 static inline
nexthop_fdb_nhc(struct nexthop * nh)537 struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
538 {
539 	struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
540 
541 	return &nhi->fib_nhc;
542 }
543 
nexthop_path_fdb_result(struct nexthop * nh,int hash)544 static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
545 							    int hash)
546 {
547 	struct nh_info *nhi;
548 	struct nexthop *nhp;
549 
550 	nhp = nexthop_select_path(nh, hash);
551 	if (unlikely(!nhp))
552 		return NULL;
553 	nhi = rcu_dereference(nhp->nh_info);
554 	return &nhi->fib_nhc;
555 }
556 #endif
557