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ab84be7e DA |
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> | |
f88d8ea6 | 13 | #include <linux/route.h> |
ab84be7e DA |
14 | #include <linux/types.h> |
15 | #include <net/ip_fib.h> | |
53010f99 | 16 | #include <net/ip6_fib.h> |
ab84be7e DA |
17 | #include <net/netlink.h> |
18 | ||
19 | #define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK | |
20 | ||
21 | struct nexthop; | |
22 | ||
23 | struct 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 | ||
597cfe4f DA |
34 | union { |
35 | __be32 ipv4; | |
53010f99 | 36 | struct in6_addr ipv6; |
597cfe4f DA |
37 | } gw; |
38 | ||
430a0491 DA |
39 | struct nlattr *nh_grp; |
40 | u16 nh_grp_type; | |
41 | ||
b513bd03 DA |
42 | struct nlattr *nh_encap; |
43 | u16 nh_encap_type; | |
44 | ||
ab84be7e DA |
45 | u32 nlflags; |
46 | struct nl_info nlinfo; | |
47 | }; | |
48 | ||
49 | struct 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; | |
597cfe4f | 58 | struct fib_nh fib_nh; |
53010f99 | 59 | struct fib6_nh fib6_nh; |
ab84be7e DA |
60 | }; |
61 | }; | |
62 | ||
430a0491 DA |
63 | struct 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 | ||
72 | struct nh_group { | |
73 | u16 num_nh; | |
74 | bool mpath; | |
75 | bool has_v4; | |
76 | struct nh_grp_entry nh_entries[0]; | |
77 | }; | |
78 | ||
ab84be7e DA |
79 | struct nexthop { |
80 | struct rb_node rb_node; /* entry on netns rbtree */ | |
4c7e8084 | 81 | struct list_head fi_list; /* v4 entries using nh */ |
f88d8ea6 | 82 | struct list_head f6i_list; /* v6 entries using nh */ |
430a0491 | 83 | struct list_head grp_list; /* nh group entries using this nh */ |
ab84be7e DA |
84 | struct net *net; |
85 | ||
86 | u32 id; | |
87 | ||
88 | u8 protocol; /* app managing this nh */ | |
89 | u8 nh_flags; | |
430a0491 | 90 | bool is_group; |
ab84be7e DA |
91 | |
92 | refcount_t refcnt; | |
93 | struct rcu_head rcu; | |
94 | ||
95 | union { | |
96 | struct nh_info __rcu *nh_info; | |
430a0491 | 97 | struct nh_group __rcu *nh_grp; |
ab84be7e DA |
98 | }; |
99 | }; | |
100 | ||
101 | /* caller is holding rcu or rtnl; no reference taken to nexthop */ | |
102 | struct nexthop *nexthop_find_by_id(struct net *net, u32 id); | |
103 | void nexthop_free_rcu(struct rcu_head *head); | |
104 | ||
105 | static inline bool nexthop_get(struct nexthop *nh) | |
106 | { | |
107 | return refcount_inc_not_zero(&nh->refcnt); | |
108 | } | |
109 | ||
110 | static 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 | ||
4c7e8084 DA |
116 | static inline bool nexthop_cmp(const struct nexthop *nh1, |
117 | const struct nexthop *nh2) | |
118 | { | |
119 | return nh1 == nh2; | |
120 | } | |
121 | ||
430a0491 DA |
122 | static 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 | ||
133 | struct nexthop *nexthop_select_path(struct nexthop *nh, int hash); | |
134 | ||
135 | static 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; | |
430a0491 DA |
144 | } |
145 | ||
146 | return rc; | |
147 | } | |
148 | ||
149 | static inline | |
150 | struct 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 | */ | |
5270041d | 157 | if (nhsel >= nhg->num_nh) |
430a0491 DA |
158 | return NULL; |
159 | ||
160 | return nhg->nh_entries[nhsel].nh; | |
161 | } | |
162 | ||
163 | static inline | |
164 | int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh) | |
165 | { | |
166 | struct nh_group *nhg = rtnl_dereference(nh->nh_grp); | |
167 | int i; | |
168 | ||
169 | for (i = 0; i < nhg->num_nh; i++) { | |
170 | struct nexthop *nhe = nhg->nh_entries[i].nh; | |
171 | struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info); | |
172 | struct fib_nh_common *nhc = &nhi->fib_nhc; | |
173 | int weight = nhg->nh_entries[i].weight; | |
174 | ||
175 | if (fib_add_nexthop(skb, nhc, weight) < 0) | |
176 | return -EMSGSIZE; | |
177 | } | |
178 | ||
179 | return 0; | |
180 | } | |
181 | ||
ab84be7e DA |
182 | /* called with rcu lock */ |
183 | static inline bool nexthop_is_blackhole(const struct nexthop *nh) | |
184 | { | |
185 | const struct nh_info *nhi; | |
186 | ||
430a0491 DA |
187 | if (nexthop_is_multipath(nh)) { |
188 | if (nexthop_num_path(nh) > 1) | |
189 | return false; | |
190 | nh = nexthop_mpath_select(nh, 0); | |
191 | if (!nh) | |
192 | return false; | |
193 | } | |
194 | ||
195 | nhi = rcu_dereference_rtnl(nh->nh_info); | |
ab84be7e DA |
196 | return nhi->reject_nh; |
197 | } | |
5481d73f | 198 | |
4c7e8084 DA |
199 | static inline void nexthop_path_fib_result(struct fib_result *res, int hash) |
200 | { | |
201 | struct nh_info *nhi; | |
202 | struct nexthop *nh; | |
203 | ||
204 | nh = nexthop_select_path(res->fi->nh, hash); | |
205 | nhi = rcu_dereference(nh->nh_info); | |
206 | res->nhc = &nhi->fib_nhc; | |
207 | } | |
208 | ||
209 | /* called with rcu read lock or rtnl held */ | |
210 | static inline | |
211 | struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel) | |
212 | { | |
213 | struct nh_info *nhi; | |
214 | ||
215 | BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0); | |
216 | BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0); | |
217 | ||
218 | if (nexthop_is_multipath(nh)) { | |
219 | nh = nexthop_mpath_select(nh, nhsel); | |
220 | if (!nh) | |
221 | return NULL; | |
222 | } | |
223 | ||
224 | nhi = rcu_dereference_rtnl(nh->nh_info); | |
225 | return &nhi->fib_nhc; | |
226 | } | |
227 | ||
5481d73f DA |
228 | static inline unsigned int fib_info_num_path(const struct fib_info *fi) |
229 | { | |
4c7e8084 DA |
230 | if (unlikely(fi->nh)) |
231 | return nexthop_num_path(fi->nh); | |
232 | ||
5481d73f DA |
233 | return fi->fib_nhs; |
234 | } | |
235 | ||
4c7e8084 DA |
236 | int fib_check_nexthop(struct nexthop *nh, u8 scope, |
237 | struct netlink_ext_ack *extack); | |
238 | ||
5481d73f DA |
239 | static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel) |
240 | { | |
4c7e8084 DA |
241 | if (unlikely(fi->nh)) |
242 | return nexthop_fib_nhc(fi->nh, nhsel); | |
243 | ||
5481d73f DA |
244 | return &fi->fib_nh[nhsel].nh_common; |
245 | } | |
246 | ||
4c7e8084 | 247 | /* only used when fib_nh is built into fib_info */ |
5481d73f DA |
248 | static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel) |
249 | { | |
4c7e8084 DA |
250 | WARN_ON(fi->nh); |
251 | ||
5481d73f DA |
252 | return &fi->fib_nh[nhsel]; |
253 | } | |
f88d8ea6 DA |
254 | |
255 | /* | |
256 | * IPv6 variants | |
257 | */ | |
258 | int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg, | |
259 | struct netlink_ext_ack *extack); | |
260 | ||
261 | static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh) | |
262 | { | |
263 | struct nh_info *nhi; | |
264 | ||
265 | if (nexthop_is_multipath(nh)) { | |
266 | nh = nexthop_mpath_select(nh, 0); | |
267 | if (!nh) | |
268 | return NULL; | |
269 | } | |
270 | ||
271 | nhi = rcu_dereference_rtnl(nh->nh_info); | |
272 | if (nhi->family == AF_INET6) | |
273 | return &nhi->fib6_nh; | |
274 | ||
275 | return NULL; | |
276 | } | |
277 | ||
278 | static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i) | |
279 | { | |
280 | struct fib6_nh *fib6_nh; | |
281 | ||
282 | fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh; | |
283 | return fib6_nh->fib_nh_dev; | |
284 | } | |
285 | ||
286 | static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash) | |
287 | { | |
288 | struct nexthop *nh = res->f6i->nh; | |
289 | struct nh_info *nhi; | |
290 | ||
291 | nh = nexthop_select_path(nh, hash); | |
292 | ||
293 | nhi = rcu_dereference_rtnl(nh->nh_info); | |
294 | if (nhi->reject_nh) { | |
295 | res->fib6_type = RTN_BLACKHOLE; | |
296 | res->fib6_flags |= RTF_REJECT; | |
297 | res->nh = nexthop_fib6_nh(nh); | |
298 | } else { | |
299 | res->nh = &nhi->fib6_nh; | |
300 | } | |
301 | } | |
f88c9aa1 DA |
302 | |
303 | int nexthop_for_each_fib6_nh(struct nexthop *nh, | |
304 | int (*cb)(struct fib6_nh *nh, void *arg), | |
305 | void *arg); | |
ab84be7e | 306 | #endif |