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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/route.h>
14#include <linux/types.h>
15#include <net/ip_fib.h>
16#include <net/ip6_fib.h>
17#include <net/netlink.h>
18
19#define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
20
21struct nexthop;
22
23struct nh_config {
24 u32 nh_id;
25
26 u8 nh_family;
27 u8 nh_protocol;
28 u8 nh_blackhole;
29 u32 nh_flags;
30
31 int nh_ifindex;
32 struct net_device *dev;
33
34 union {
35 __be32 ipv4;
36 struct in6_addr ipv6;
37 } gw;
38
39 struct nlattr *nh_grp;
40 u16 nh_grp_type;
41
42 struct nlattr *nh_encap;
43 u16 nh_encap_type;
44
45 u32 nlflags;
46 struct nl_info nlinfo;
47};
48
49struct nh_info {
50 struct hlist_node dev_hash; /* entry on netns devhash */
51 struct nexthop *nh_parent;
52
53 u8 family;
54 bool reject_nh;
55
56 union {
57 struct fib_nh_common fib_nhc;
58 struct fib_nh fib_nh;
59 struct fib6_nh fib6_nh;
60 };
61};
62
63struct nh_grp_entry {
64 struct nexthop *nh;
65 u8 weight;
66 atomic_t upper_bound;
67
68 struct list_head nh_list;
69 struct nexthop *nh_parent; /* nexthop of group with this entry */
70};
71
72struct nh_group {
73 u16 num_nh;
74 bool mpath;
75 bool has_v4;
76 struct nh_grp_entry nh_entries[0];
77};
78
79struct nexthop {
80 struct rb_node rb_node; /* entry on netns rbtree */
81 struct list_head fi_list; /* v4 entries using nh */
82 struct list_head f6i_list; /* v6 entries using nh */
83 struct list_head grp_list; /* nh group entries using this nh */
84 struct net *net;
85
86 u32 id;
87
88 u8 protocol; /* app managing this nh */
89 u8 nh_flags;
90 bool is_group;
91
92 refcount_t refcnt;
93 struct rcu_head rcu;
94
95 union {
96 struct nh_info __rcu *nh_info;
97 struct nh_group __rcu *nh_grp;
98 };
99};
100
101/* caller is holding rcu or rtnl; no reference taken to nexthop */
102struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
103void nexthop_free_rcu(struct rcu_head *head);
104
105static inline bool nexthop_get(struct nexthop *nh)
106{
107 return refcount_inc_not_zero(&nh->refcnt);
108}
109
110static inline void nexthop_put(struct nexthop *nh)
111{
112 if (refcount_dec_and_test(&nh->refcnt))
113 call_rcu(&nh->rcu, nexthop_free_rcu);
114}
115
116static inline bool nexthop_cmp(const struct nexthop *nh1,
117 const struct nexthop *nh2)
118{
119 return nh1 == nh2;
120}
121
122static inline bool nexthop_is_multipath(const struct nexthop *nh)
123{
124 if (nh->is_group) {
125 struct nh_group *nh_grp;
126
127 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
128 return nh_grp->mpath;
129 }
130 return false;
131}
132
133struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
134
135static inline unsigned int nexthop_num_path(const struct nexthop *nh)
136{
137 unsigned int rc = 1;
138
139 if (nexthop_is_multipath(nh)) {
140 struct nh_group *nh_grp;
141
142 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
143 rc = nh_grp->num_nh;
144 }
145
146 return rc;
147}
148
149static inline
150struct nexthop *nexthop_mpath_select(const struct nexthop *nh, int nhsel)
151{
152 const struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
153
154 /* for_nexthops macros in fib_semantics.c grabs a pointer to
155 * the nexthop before checking nhsel
156 */
157 if (nhsel >= nhg->num_nh)
158 return NULL;
159
160 return nhg->nh_entries[nhsel].nh;
161}
162
163static inline
164int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
165 u8 rt_family)
166{
167 struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
168 int i;
169
170 for (i = 0; i < nhg->num_nh; i++) {
171 struct nexthop *nhe = nhg->nh_entries[i].nh;
172 struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
173 struct fib_nh_common *nhc = &nhi->fib_nhc;
174 int weight = nhg->nh_entries[i].weight;
175
176 if (fib_add_nexthop(skb, nhc, weight, rt_family) < 0)
177 return -EMSGSIZE;
178 }
179
180 return 0;
181}
182
183/* called with rcu lock */
184static inline bool nexthop_is_blackhole(const struct nexthop *nh)
185{
186 const struct nh_info *nhi;
187
188 if (nexthop_is_multipath(nh)) {
189 if (nexthop_num_path(nh) > 1)
190 return false;
191 nh = nexthop_mpath_select(nh, 0);
192 if (!nh)
193 return false;
194 }
195
196 nhi = rcu_dereference_rtnl(nh->nh_info);
197 return nhi->reject_nh;
198}
199
200static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
201{
202 struct nh_info *nhi;
203 struct nexthop *nh;
204
205 nh = nexthop_select_path(res->fi->nh, hash);
206 nhi = rcu_dereference(nh->nh_info);
207 res->nhc = &nhi->fib_nhc;
208}
209
210/* called with rcu read lock or rtnl held */
211static inline
212struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
213{
214 struct nh_info *nhi;
215
216 BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
217 BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
218
219 if (nexthop_is_multipath(nh)) {
220 nh = nexthop_mpath_select(nh, nhsel);
221 if (!nh)
222 return NULL;
223 }
224
225 nhi = rcu_dereference_rtnl(nh->nh_info);
226 return &nhi->fib_nhc;
227}
228
229static inline unsigned int fib_info_num_path(const struct fib_info *fi)
230{
231 if (unlikely(fi->nh))
232 return nexthop_num_path(fi->nh);
233
234 return fi->fib_nhs;
235}
236
237int fib_check_nexthop(struct nexthop *nh, u8 scope,
238 struct netlink_ext_ack *extack);
239
240static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
241{
242 if (unlikely(fi->nh))
243 return nexthop_fib_nhc(fi->nh, nhsel);
244
245 return &fi->fib_nh[nhsel].nh_common;
246}
247
248/* only used when fib_nh is built into fib_info */
249static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
250{
251 WARN_ON(fi->nh);
252
253 return &fi->fib_nh[nhsel];
254}
255
256/*
257 * IPv6 variants
258 */
259int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
260 struct netlink_ext_ack *extack);
261
262static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
263{
264 struct nh_info *nhi;
265
266 if (nexthop_is_multipath(nh)) {
267 nh = nexthop_mpath_select(nh, 0);
268 if (!nh)
269 return NULL;
270 }
271
272 nhi = rcu_dereference_rtnl(nh->nh_info);
273 if (nhi->family == AF_INET6)
274 return &nhi->fib6_nh;
275
276 return NULL;
277}
278
279static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
280{
281 struct fib6_nh *fib6_nh;
282
283 fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
284 return fib6_nh->fib_nh_dev;
285}
286
287static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
288{
289 struct nexthop *nh = res->f6i->nh;
290 struct nh_info *nhi;
291
292 nh = nexthop_select_path(nh, hash);
293
294 nhi = rcu_dereference_rtnl(nh->nh_info);
295 if (nhi->reject_nh) {
296 res->fib6_type = RTN_BLACKHOLE;
297 res->fib6_flags |= RTF_REJECT;
298 res->nh = nexthop_fib6_nh(nh);
299 } else {
300 res->nh = &nhi->fib6_nh;
301 }
302}
303
304int nexthop_for_each_fib6_nh(struct nexthop *nh,
305 int (*cb)(struct fib6_nh *nh, void *arg),
306 void *arg);
307#endif
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
44 struct nlattr *nh_encap;
45 u16 nh_encap_type;
46
47 u32 nlflags;
48 struct nl_info nlinfo;
49};
50
51struct nh_info {
52 struct hlist_node dev_hash; /* entry on netns devhash */
53 struct nexthop *nh_parent;
54
55 u8 family;
56 bool reject_nh;
57 bool fdb_nh;
58
59 union {
60 struct fib_nh_common fib_nhc;
61 struct fib_nh fib_nh;
62 struct fib6_nh fib6_nh;
63 };
64};
65
66struct nh_grp_entry {
67 struct nexthop *nh;
68 u8 weight;
69 atomic_t upper_bound;
70
71 struct list_head nh_list;
72 struct nexthop *nh_parent; /* nexthop of group with this entry */
73};
74
75struct nh_group {
76 struct nh_group *spare; /* spare group for removals */
77 u16 num_nh;
78 bool mpath;
79 bool fdb_nh;
80 bool has_v4;
81 struct nh_grp_entry nh_entries[];
82};
83
84struct nexthop {
85 struct rb_node rb_node; /* entry on netns rbtree */
86 struct list_head fi_list; /* v4 entries using nh */
87 struct list_head f6i_list; /* v6 entries using nh */
88 struct list_head fdb_list; /* fdb entries using this nh */
89 struct list_head grp_list; /* nh group entries using this nh */
90 struct net *net;
91
92 u32 id;
93
94 u8 protocol; /* app managing this nh */
95 u8 nh_flags;
96 bool is_group;
97
98 refcount_t refcnt;
99 struct rcu_head rcu;
100
101 union {
102 struct nh_info __rcu *nh_info;
103 struct nh_group __rcu *nh_grp;
104 };
105};
106
107enum nexthop_event_type {
108 NEXTHOP_EVENT_ADD,
109 NEXTHOP_EVENT_DEL
110};
111
112int call_nexthop_notifier(struct notifier_block *nb, struct net *net,
113 enum nexthop_event_type event_type,
114 struct nexthop *nh);
115int register_nexthop_notifier(struct net *net, struct notifier_block *nb);
116int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
117
118/* caller is holding rcu or rtnl; no reference taken to nexthop */
119struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
120void nexthop_free_rcu(struct rcu_head *head);
121
122static inline bool nexthop_get(struct nexthop *nh)
123{
124 return refcount_inc_not_zero(&nh->refcnt);
125}
126
127static inline void nexthop_put(struct nexthop *nh)
128{
129 if (refcount_dec_and_test(&nh->refcnt))
130 call_rcu(&nh->rcu, nexthop_free_rcu);
131}
132
133static inline bool nexthop_cmp(const struct nexthop *nh1,
134 const struct nexthop *nh2)
135{
136 return nh1 == nh2;
137}
138
139static inline bool nexthop_is_fdb(const struct nexthop *nh)
140{
141 if (nh->is_group) {
142 const struct nh_group *nh_grp;
143
144 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
145 return nh_grp->fdb_nh;
146 } else {
147 const struct nh_info *nhi;
148
149 nhi = rcu_dereference_rtnl(nh->nh_info);
150 return nhi->fdb_nh;
151 }
152}
153
154static inline bool nexthop_has_v4(const struct nexthop *nh)
155{
156 if (nh->is_group) {
157 struct nh_group *nh_grp;
158
159 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
160 return nh_grp->has_v4;
161 }
162 return false;
163}
164
165static inline bool nexthop_is_multipath(const struct nexthop *nh)
166{
167 if (nh->is_group) {
168 struct nh_group *nh_grp;
169
170 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
171 return nh_grp->mpath;
172 }
173 return false;
174}
175
176struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
177
178static inline unsigned int nexthop_num_path(const struct nexthop *nh)
179{
180 unsigned int rc = 1;
181
182 if (nh->is_group) {
183 struct nh_group *nh_grp;
184
185 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
186 if (nh_grp->mpath)
187 rc = nh_grp->num_nh;
188 }
189
190 return rc;
191}
192
193static inline
194struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
195{
196 /* for_nexthops macros in fib_semantics.c grabs a pointer to
197 * the nexthop before checking nhsel
198 */
199 if (nhsel >= nhg->num_nh)
200 return NULL;
201
202 return nhg->nh_entries[nhsel].nh;
203}
204
205static inline
206int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
207 u8 rt_family)
208{
209 struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
210 int i;
211
212 for (i = 0; i < nhg->num_nh; i++) {
213 struct nexthop *nhe = nhg->nh_entries[i].nh;
214 struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
215 struct fib_nh_common *nhc = &nhi->fib_nhc;
216 int weight = nhg->nh_entries[i].weight;
217
218 if (fib_add_nexthop(skb, nhc, weight, rt_family) < 0)
219 return -EMSGSIZE;
220 }
221
222 return 0;
223}
224
225/* called with rcu lock */
226static inline bool nexthop_is_blackhole(const struct nexthop *nh)
227{
228 const struct nh_info *nhi;
229
230 if (nh->is_group) {
231 struct nh_group *nh_grp;
232
233 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
234 if (nh_grp->num_nh > 1)
235 return false;
236
237 nh = nh_grp->nh_entries[0].nh;
238 }
239
240 nhi = rcu_dereference_rtnl(nh->nh_info);
241 return nhi->reject_nh;
242}
243
244static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
245{
246 struct nh_info *nhi;
247 struct nexthop *nh;
248
249 nh = nexthop_select_path(res->fi->nh, hash);
250 nhi = rcu_dereference(nh->nh_info);
251 res->nhc = &nhi->fib_nhc;
252}
253
254/* called with rcu read lock or rtnl held */
255static inline
256struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
257{
258 struct nh_info *nhi;
259
260 BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
261 BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
262
263 if (nh->is_group) {
264 struct nh_group *nh_grp;
265
266 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
267 if (nh_grp->mpath) {
268 nh = nexthop_mpath_select(nh_grp, nhsel);
269 if (!nh)
270 return NULL;
271 }
272 }
273
274 nhi = rcu_dereference_rtnl(nh->nh_info);
275 return &nhi->fib_nhc;
276}
277
278/* called from fib_table_lookup with rcu_lock */
279static inline
280struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
281 int fib_flags,
282 const struct flowi4 *flp,
283 int *nhsel)
284{
285 struct nh_info *nhi;
286
287 if (nh->is_group) {
288 struct nh_group *nhg = rcu_dereference(nh->nh_grp);
289 int i;
290
291 for (i = 0; i < nhg->num_nh; i++) {
292 struct nexthop *nhe = nhg->nh_entries[i].nh;
293
294 nhi = rcu_dereference(nhe->nh_info);
295 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
296 *nhsel = i;
297 return &nhi->fib_nhc;
298 }
299 }
300 } else {
301 nhi = rcu_dereference(nh->nh_info);
302 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
303 *nhsel = 0;
304 return &nhi->fib_nhc;
305 }
306 }
307
308 return NULL;
309}
310
311static inline bool nexthop_uses_dev(const struct nexthop *nh,
312 const struct net_device *dev)
313{
314 struct nh_info *nhi;
315
316 if (nh->is_group) {
317 struct nh_group *nhg = rcu_dereference(nh->nh_grp);
318 int i;
319
320 for (i = 0; i < nhg->num_nh; i++) {
321 struct nexthop *nhe = nhg->nh_entries[i].nh;
322
323 nhi = rcu_dereference(nhe->nh_info);
324 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
325 return true;
326 }
327 } else {
328 nhi = rcu_dereference(nh->nh_info);
329 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
330 return true;
331 }
332
333 return false;
334}
335
336static inline unsigned int fib_info_num_path(const struct fib_info *fi)
337{
338 if (unlikely(fi->nh))
339 return nexthop_num_path(fi->nh);
340
341 return fi->fib_nhs;
342}
343
344int fib_check_nexthop(struct nexthop *nh, u8 scope,
345 struct netlink_ext_ack *extack);
346
347static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
348{
349 if (unlikely(fi->nh))
350 return nexthop_fib_nhc(fi->nh, nhsel);
351
352 return &fi->fib_nh[nhsel].nh_common;
353}
354
355/* only used when fib_nh is built into fib_info */
356static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
357{
358 WARN_ON(fi->nh);
359
360 return &fi->fib_nh[nhsel];
361}
362
363/*
364 * IPv6 variants
365 */
366int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
367 struct netlink_ext_ack *extack);
368
369static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
370{
371 struct nh_info *nhi;
372
373 if (nh->is_group) {
374 struct nh_group *nh_grp;
375
376 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
377 nh = nexthop_mpath_select(nh_grp, 0);
378 if (!nh)
379 return NULL;
380 }
381
382 nhi = rcu_dereference_rtnl(nh->nh_info);
383 if (nhi->family == AF_INET6)
384 return &nhi->fib6_nh;
385
386 return NULL;
387}
388
389static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
390{
391 struct fib6_nh *fib6_nh;
392
393 fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
394 return fib6_nh->fib_nh_dev;
395}
396
397static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
398{
399 struct nexthop *nh = res->f6i->nh;
400 struct nh_info *nhi;
401
402 nh = nexthop_select_path(nh, hash);
403
404 nhi = rcu_dereference_rtnl(nh->nh_info);
405 if (nhi->reject_nh) {
406 res->fib6_type = RTN_BLACKHOLE;
407 res->fib6_flags |= RTF_REJECT;
408 res->nh = nexthop_fib6_nh(nh);
409 } else {
410 res->nh = &nhi->fib6_nh;
411 }
412}
413
414int nexthop_for_each_fib6_nh(struct nexthop *nh,
415 int (*cb)(struct fib6_nh *nh, void *arg),
416 void *arg);
417
418static inline int nexthop_get_family(struct nexthop *nh)
419{
420 struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
421
422 return nhi->family;
423}
424
425static inline
426struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
427{
428 struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
429
430 return &nhi->fib_nhc;
431}
432
433static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
434 int hash)
435{
436 struct nh_info *nhi;
437 struct nexthop *nhp;
438
439 nhp = nexthop_select_path(nh, hash);
440 if (unlikely(!nhp))
441 return NULL;
442 nhi = rcu_dereference(nhp->nh_info);
443 return &nhi->fib_nhc;
444}
445#endif