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 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
59 struct 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
74 struct 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
82 struct 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
100 struct nh_grp_entry_stats {
101 u64_stats_t packets;
102 struct u64_stats_sync syncp;
103 };
104
105 struct 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
128 struct 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
142 struct 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
156 refcount_t refcnt;
157 struct rcu_head rcu;
158
159 union {
160 struct nh_info __rcu *nh_info;
161 struct nh_group __rcu *nh_grp;
162 };
163 };
164
165 enum nexthop_event_type {
166 NEXTHOP_EVENT_DEL,
167 NEXTHOP_EVENT_REPLACE,
168 NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
169 NEXTHOP_EVENT_BUCKET_REPLACE,
170 NEXTHOP_EVENT_HW_STATS_REPORT_DELTA,
171 };
172
173 enum nh_notifier_info_type {
174 NH_NOTIFIER_INFO_TYPE_SINGLE,
175 NH_NOTIFIER_INFO_TYPE_GRP,
176 NH_NOTIFIER_INFO_TYPE_RES_TABLE,
177 NH_NOTIFIER_INFO_TYPE_RES_BUCKET,
178 NH_NOTIFIER_INFO_TYPE_GRP_HW_STATS,
179 };
180
181 struct nh_notifier_single_info {
182 struct net_device *dev;
183 u8 gw_family;
184 union {
185 __be32 ipv4;
186 struct in6_addr ipv6;
187 };
188 u32 id;
189 u8 is_reject:1,
190 is_fdb:1,
191 has_encap:1;
192 };
193
194 struct nh_notifier_grp_entry_info {
195 u16 weight;
196 struct nh_notifier_single_info nh;
197 };
198
199 struct nh_notifier_grp_info {
200 u16 num_nh;
201 bool is_fdb;
202 bool hw_stats;
203 struct nh_notifier_grp_entry_info nh_entries[] __counted_by(num_nh);
204 };
205
206 struct nh_notifier_res_bucket_info {
207 u16 bucket_index;
208 unsigned int idle_timer_ms;
209 bool force;
210 struct nh_notifier_single_info old_nh;
211 struct nh_notifier_single_info new_nh;
212 };
213
214 struct nh_notifier_res_table_info {
215 u16 num_nh_buckets;
216 bool hw_stats;
217 struct nh_notifier_single_info nhs[] __counted_by(num_nh_buckets);
218 };
219
220 struct nh_notifier_grp_hw_stats_entry_info {
221 u32 id;
222 u64 packets;
223 };
224
225 struct nh_notifier_grp_hw_stats_info {
226 u16 num_nh;
227 bool hw_stats_used;
228 struct nh_notifier_grp_hw_stats_entry_info stats[] __counted_by(num_nh);
229 };
230
231 struct nh_notifier_info {
232 struct net *net;
233 struct netlink_ext_ack *extack;
234 u32 id;
235 enum nh_notifier_info_type type;
236 union {
237 struct nh_notifier_single_info *nh;
238 struct nh_notifier_grp_info *nh_grp;
239 struct nh_notifier_res_table_info *nh_res_table;
240 struct nh_notifier_res_bucket_info *nh_res_bucket;
241 struct nh_notifier_grp_hw_stats_info *nh_grp_hw_stats;
242 };
243 };
244
245 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
246 struct netlink_ext_ack *extack);
247 int __unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
248 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
249 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
250 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
251 bool offload, bool trap);
252 void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
253 unsigned long *activity);
254 void nh_grp_hw_stats_report_delta(struct nh_notifier_grp_hw_stats_info *info,
255 unsigned int nh_idx,
256 u64 delta_packets);
257
258 /* caller is holding rcu or rtnl; no reference taken to nexthop */
259 struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
260 void nexthop_free_rcu(struct rcu_head *head);
261
nexthop_get(struct nexthop * nh)262 static inline bool nexthop_get(struct nexthop *nh)
263 {
264 return refcount_inc_not_zero(&nh->refcnt);
265 }
266
nexthop_put(struct nexthop * nh)267 static inline void nexthop_put(struct nexthop *nh)
268 {
269 if (refcount_dec_and_test(&nh->refcnt))
270 call_rcu_hurry(&nh->rcu, nexthop_free_rcu);
271 }
272
nexthop_cmp(const struct nexthop * nh1,const struct nexthop * nh2)273 static inline bool nexthop_cmp(const struct nexthop *nh1,
274 const struct nexthop *nh2)
275 {
276 return nh1 == nh2;
277 }
278
nexthop_is_fdb(const struct nexthop * nh)279 static inline bool nexthop_is_fdb(const struct nexthop *nh)
280 {
281 if (nh->is_group) {
282 const struct nh_group *nh_grp;
283
284 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
285 return nh_grp->fdb_nh;
286 } else {
287 const struct nh_info *nhi;
288
289 nhi = rcu_dereference_rtnl(nh->nh_info);
290 return nhi->fdb_nh;
291 }
292 }
293
nexthop_has_v4(const struct nexthop * nh)294 static inline bool nexthop_has_v4(const struct nexthop *nh)
295 {
296 if (nh->is_group) {
297 struct nh_group *nh_grp;
298
299 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
300 return nh_grp->has_v4;
301 }
302 return false;
303 }
304
nexthop_is_multipath(const struct nexthop * nh)305 static inline bool nexthop_is_multipath(const struct nexthop *nh)
306 {
307 if (nh->is_group) {
308 struct nh_group *nh_grp;
309
310 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
311 return nh_grp->is_multipath;
312 }
313 return false;
314 }
315
316 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
317
nexthop_num_path(const struct nexthop * nh)318 static inline unsigned int nexthop_num_path(const struct nexthop *nh)
319 {
320 unsigned int rc = 1;
321
322 if (nh->is_group) {
323 struct nh_group *nh_grp;
324
325 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
326 if (nh_grp->is_multipath)
327 rc = nh_grp->num_nh;
328 }
329
330 return rc;
331 }
332
333 static inline
nexthop_mpath_select(const struct nh_group * nhg,int nhsel)334 struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
335 {
336 /* for_nexthops macros in fib_semantics.c grabs a pointer to
337 * the nexthop before checking nhsel
338 */
339 if (nhsel >= nhg->num_nh)
340 return NULL;
341
342 return nhg->nh_entries[nhsel].nh;
343 }
344
345 static inline
nexthop_mpath_fill_node(struct sk_buff * skb,struct nexthop * nh,u8 rt_family)346 int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
347 u8 rt_family)
348 {
349 struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
350 int i;
351
352 for (i = 0; i < nhg->num_nh; i++) {
353 struct nexthop *nhe = nhg->nh_entries[i].nh;
354 struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
355 struct fib_nh_common *nhc = &nhi->fib_nhc;
356 int weight = nhg->nh_entries[i].weight;
357
358 if (fib_add_nexthop(skb, nhc, weight, rt_family, 0) < 0)
359 return -EMSGSIZE;
360 }
361
362 return 0;
363 }
364
365 /* called with rcu lock */
nexthop_is_blackhole(const struct nexthop * nh)366 static inline bool nexthop_is_blackhole(const struct nexthop *nh)
367 {
368 const struct nh_info *nhi;
369
370 if (nh->is_group) {
371 struct nh_group *nh_grp;
372
373 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
374 if (nh_grp->num_nh > 1)
375 return false;
376
377 nh = nh_grp->nh_entries[0].nh;
378 }
379
380 nhi = rcu_dereference_rtnl(nh->nh_info);
381 return nhi->reject_nh;
382 }
383
nexthop_path_fib_result(struct fib_result * res,int hash)384 static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
385 {
386 struct nh_info *nhi;
387 struct nexthop *nh;
388
389 nh = nexthop_select_path(res->fi->nh, hash);
390 nhi = rcu_dereference(nh->nh_info);
391 res->nhc = &nhi->fib_nhc;
392 }
393
394 /* called with rcu read lock or rtnl held */
395 static inline
nexthop_fib_nhc(struct nexthop * nh,int nhsel)396 struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
397 {
398 struct nh_info *nhi;
399
400 BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
401 BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
402
403 if (nh->is_group) {
404 struct nh_group *nh_grp;
405
406 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
407 if (nh_grp->is_multipath) {
408 nh = nexthop_mpath_select(nh_grp, nhsel);
409 if (!nh)
410 return NULL;
411 }
412 }
413
414 nhi = rcu_dereference_rtnl(nh->nh_info);
415 return &nhi->fib_nhc;
416 }
417
418 /* called from fib_table_lookup with rcu_lock */
419 static inline
nexthop_get_nhc_lookup(const struct nexthop * nh,int fib_flags,const struct flowi4 * flp,int * nhsel)420 struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
421 int fib_flags,
422 const struct flowi4 *flp,
423 int *nhsel)
424 {
425 struct nh_info *nhi;
426
427 if (nh->is_group) {
428 struct nh_group *nhg = rcu_dereference(nh->nh_grp);
429 int i;
430
431 for (i = 0; i < nhg->num_nh; i++) {
432 struct nexthop *nhe = nhg->nh_entries[i].nh;
433
434 nhi = rcu_dereference(nhe->nh_info);
435 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
436 *nhsel = i;
437 return &nhi->fib_nhc;
438 }
439 }
440 } else {
441 nhi = rcu_dereference(nh->nh_info);
442 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
443 *nhsel = 0;
444 return &nhi->fib_nhc;
445 }
446 }
447
448 return NULL;
449 }
450
nexthop_uses_dev(const struct nexthop * nh,const struct net_device * dev)451 static inline bool nexthop_uses_dev(const struct nexthop *nh,
452 const struct net_device *dev)
453 {
454 struct nh_info *nhi;
455
456 if (nh->is_group) {
457 struct nh_group *nhg = rcu_dereference(nh->nh_grp);
458 int i;
459
460 for (i = 0; i < nhg->num_nh; i++) {
461 struct nexthop *nhe = nhg->nh_entries[i].nh;
462
463 nhi = rcu_dereference(nhe->nh_info);
464 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
465 return true;
466 }
467 } else {
468 nhi = rcu_dereference(nh->nh_info);
469 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
470 return true;
471 }
472
473 return false;
474 }
475
fib_info_num_path(const struct fib_info * fi)476 static inline unsigned int fib_info_num_path(const struct fib_info *fi)
477 {
478 if (unlikely(fi->nh))
479 return nexthop_num_path(fi->nh);
480
481 return fi->fib_nhs;
482 }
483
484 int fib_check_nexthop(struct nexthop *nh, u8 scope,
485 struct netlink_ext_ack *extack);
486
fib_info_nhc(struct fib_info * fi,int nhsel)487 static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
488 {
489 if (unlikely(fi->nh))
490 return nexthop_fib_nhc(fi->nh, nhsel);
491
492 return &fi->fib_nh[nhsel].nh_common;
493 }
494
495 /* only used when fib_nh is built into fib_info */
fib_info_nh(struct fib_info * fi,int nhsel)496 static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
497 {
498 WARN_ON(fi->nh);
499
500 return &fi->fib_nh[nhsel];
501 }
502
503 /*
504 * IPv6 variants
505 */
506 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
507 struct netlink_ext_ack *extack);
508
509 /* Caller should either hold rcu_read_lock(), or RTNL. */
nexthop_fib6_nh(struct nexthop * nh)510 static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
511 {
512 struct nh_info *nhi;
513
514 if (nh->is_group) {
515 struct nh_group *nh_grp;
516
517 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
518 nh = nexthop_mpath_select(nh_grp, 0);
519 if (!nh)
520 return NULL;
521 }
522
523 nhi = rcu_dereference_rtnl(nh->nh_info);
524 if (nhi->family == AF_INET6)
525 return &nhi->fib6_nh;
526
527 return NULL;
528 }
529
fib6_info_nh_dev(struct fib6_info * f6i)530 static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
531 {
532 struct fib6_nh *fib6_nh;
533
534 fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
535 return fib6_nh->fib_nh_dev;
536 }
537
nexthop_path_fib6_result(struct fib6_result * res,int hash)538 static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
539 {
540 struct nexthop *nh = res->f6i->nh;
541 struct nh_info *nhi;
542
543 nh = nexthop_select_path(nh, hash);
544
545 nhi = rcu_dereference_rtnl(nh->nh_info);
546 if (nhi->reject_nh) {
547 res->fib6_type = RTN_BLACKHOLE;
548 res->fib6_flags |= RTF_REJECT;
549 res->nh = nexthop_fib6_nh(nh);
550 } else {
551 res->nh = &nhi->fib6_nh;
552 }
553 }
554
555 int nexthop_for_each_fib6_nh(struct nexthop *nh,
556 int (*cb)(struct fib6_nh *nh, void *arg),
557 void *arg);
558
nexthop_get_family(struct nexthop * nh)559 static inline int nexthop_get_family(struct nexthop *nh)
560 {
561 struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
562
563 return nhi->family;
564 }
565
566 static inline
nexthop_fdb_nhc(struct nexthop * nh)567 struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
568 {
569 struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
570
571 return &nhi->fib_nhc;
572 }
573
nexthop_path_fdb_result(struct nexthop * nh,int hash)574 static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
575 int hash)
576 {
577 struct nh_info *nhi;
578 struct nexthop *nhp;
579
580 nhp = nexthop_select_path(nh, hash);
581 if (unlikely(!nhp))
582 return NULL;
583 nhi = rcu_dereference(nhp->nh_info);
584 return &nhi->fib_nhc;
585 }
586 #endif
587