Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : #ifndef __NET_GENERIC_NETLINK_H
3 : #define __NET_GENERIC_NETLINK_H
4 :
5 : #include <linux/genetlink.h>
6 : #include <net/netlink.h>
7 : #include <net/net_namespace.h>
8 :
9 : #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
10 :
11 : /**
12 : * struct genl_multicast_group - generic netlink multicast group
13 : * @name: name of the multicast group, names are per-family
14 : */
15 : struct genl_multicast_group {
16 : char name[GENL_NAMSIZ];
17 : u8 flags;
18 : };
19 :
20 : struct genl_ops;
21 : struct genl_info;
22 :
23 : /**
24 : * struct genl_family - generic netlink family
25 : * @id: protocol family identifier (private)
26 : * @hdrsize: length of user specific header in bytes
27 : * @name: name of family
28 : * @version: protocol version
29 : * @maxattr: maximum number of attributes supported
30 : * @policy: netlink policy
31 : * @netnsok: set to true if the family can handle network
32 : * namespaces and should be presented in all of them
33 : * @parallel_ops: operations can be called in parallel and aren't
34 : * synchronized by the core genetlink code
35 : * @pre_doit: called before an operation's doit callback, it may
36 : * do additional, common, filtering and return an error
37 : * @post_doit: called after an operation's doit callback, it may
38 : * undo operations done by pre_doit, for example release locks
39 : * @mcgrps: multicast groups used by this family
40 : * @n_mcgrps: number of multicast groups
41 : * @mcgrp_offset: starting number of multicast group IDs in this family
42 : * (private)
43 : * @ops: the operations supported by this family
44 : * @n_ops: number of operations supported by this family
45 : * @small_ops: the small-struct operations supported by this family
46 : * @n_small_ops: number of small-struct operations supported by this family
47 : */
48 : struct genl_family {
49 : int id; /* private */
50 : unsigned int hdrsize;
51 : char name[GENL_NAMSIZ];
52 : unsigned int version;
53 : unsigned int maxattr;
54 : unsigned int mcgrp_offset; /* private */
55 : u8 netnsok:1;
56 : u8 parallel_ops:1;
57 : u8 n_ops;
58 : u8 n_small_ops;
59 : u8 n_mcgrps;
60 : const struct nla_policy *policy;
61 : int (*pre_doit)(const struct genl_ops *ops,
62 : struct sk_buff *skb,
63 : struct genl_info *info);
64 : void (*post_doit)(const struct genl_ops *ops,
65 : struct sk_buff *skb,
66 : struct genl_info *info);
67 : const struct genl_ops * ops;
68 : const struct genl_small_ops *small_ops;
69 : const struct genl_multicast_group *mcgrps;
70 : struct module *module;
71 : };
72 :
73 : /**
74 : * struct genl_info - receiving information
75 : * @snd_seq: sending sequence number
76 : * @snd_portid: netlink portid of sender
77 : * @nlhdr: netlink message header
78 : * @genlhdr: generic netlink message header
79 : * @userhdr: user specific header
80 : * @attrs: netlink attributes
81 : * @_net: network namespace
82 : * @user_ptr: user pointers
83 : * @extack: extended ACK report struct
84 : */
85 : struct genl_info {
86 : u32 snd_seq;
87 : u32 snd_portid;
88 : struct nlmsghdr * nlhdr;
89 : struct genlmsghdr * genlhdr;
90 : void * userhdr;
91 : struct nlattr ** attrs;
92 : possible_net_t _net;
93 : void * user_ptr[2];
94 : struct netlink_ext_ack *extack;
95 : };
96 :
97 0 : static inline struct net *genl_info_net(struct genl_info *info)
98 : {
99 0 : return read_pnet(&info->_net);
100 : }
101 :
102 0 : static inline void genl_info_net_set(struct genl_info *info, struct net *net)
103 : {
104 0 : write_pnet(&info->_net, net);
105 : }
106 :
107 : #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
108 :
109 : enum genl_validate_flags {
110 : GENL_DONT_VALIDATE_STRICT = BIT(0),
111 : GENL_DONT_VALIDATE_DUMP = BIT(1),
112 : GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
113 : };
114 :
115 : /**
116 : * struct genl_small_ops - generic netlink operations (small version)
117 : * @cmd: command identifier
118 : * @internal_flags: flags used by the family
119 : * @flags: flags
120 : * @validate: validation flags from enum genl_validate_flags
121 : * @doit: standard command callback
122 : * @dumpit: callback for dumpers
123 : *
124 : * This is a cut-down version of struct genl_ops for users who don't need
125 : * most of the ancillary infra and want to save space.
126 : */
127 : struct genl_small_ops {
128 : int (*doit)(struct sk_buff *skb, struct genl_info *info);
129 : int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
130 : u8 cmd;
131 : u8 internal_flags;
132 : u8 flags;
133 : u8 validate;
134 : };
135 :
136 : /**
137 : * struct genl_ops - generic netlink operations
138 : * @cmd: command identifier
139 : * @internal_flags: flags used by the family
140 : * @flags: flags
141 : * @maxattr: maximum number of attributes supported
142 : * @policy: netlink policy (takes precedence over family policy)
143 : * @validate: validation flags from enum genl_validate_flags
144 : * @doit: standard command callback
145 : * @start: start callback for dumps
146 : * @dumpit: callback for dumpers
147 : * @done: completion callback for dumps
148 : */
149 : struct genl_ops {
150 : int (*doit)(struct sk_buff *skb,
151 : struct genl_info *info);
152 : int (*start)(struct netlink_callback *cb);
153 : int (*dumpit)(struct sk_buff *skb,
154 : struct netlink_callback *cb);
155 : int (*done)(struct netlink_callback *cb);
156 : const struct nla_policy *policy;
157 : unsigned int maxattr;
158 : u8 cmd;
159 : u8 internal_flags;
160 : u8 flags;
161 : u8 validate;
162 : };
163 :
164 : /**
165 : * struct genl_info - info that is available during dumpit op call
166 : * @family: generic netlink family - for internal genl code usage
167 : * @ops: generic netlink ops - for internal genl code usage
168 : * @attrs: netlink attributes
169 : */
170 : struct genl_dumpit_info {
171 : const struct genl_family *family;
172 : struct genl_ops op;
173 : struct nlattr **attrs;
174 : };
175 :
176 : static inline const struct genl_dumpit_info *
177 0 : genl_dumpit_info(struct netlink_callback *cb)
178 : {
179 0 : return cb->data;
180 : }
181 :
182 : int genl_register_family(struct genl_family *family);
183 : int genl_unregister_family(const struct genl_family *family);
184 : void genl_notify(const struct genl_family *family, struct sk_buff *skb,
185 : struct genl_info *info, u32 group, gfp_t flags);
186 :
187 : void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
188 : const struct genl_family *family, int flags, u8 cmd);
189 :
190 : /**
191 : * genlmsg_nlhdr - Obtain netlink header from user specified header
192 : * @user_hdr: user header as returned from genlmsg_put()
193 : *
194 : * Returns pointer to netlink header.
195 : */
196 : static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
197 : {
198 : return (struct nlmsghdr *)((char *)user_hdr -
199 : GENL_HDRLEN -
200 : NLMSG_HDRLEN);
201 : }
202 :
203 : /**
204 : * genlmsg_parse_deprecated - parse attributes of a genetlink message
205 : * @nlh: netlink message header
206 : * @family: genetlink message family
207 : * @tb: destination array with maxtype+1 elements
208 : * @maxtype: maximum attribute type to be expected
209 : * @policy: validation policy
210 : * @extack: extended ACK report struct
211 : */
212 : static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
213 : const struct genl_family *family,
214 : struct nlattr *tb[], int maxtype,
215 : const struct nla_policy *policy,
216 : struct netlink_ext_ack *extack)
217 : {
218 : return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
219 : policy, NL_VALIDATE_LIBERAL, extack);
220 : }
221 :
222 : /**
223 : * genlmsg_parse - parse attributes of a genetlink message
224 : * @nlh: netlink message header
225 : * @family: genetlink message family
226 : * @tb: destination array with maxtype+1 elements
227 : * @maxtype: maximum attribute type to be expected
228 : * @policy: validation policy
229 : * @extack: extended ACK report struct
230 : */
231 : static inline int genlmsg_parse(const struct nlmsghdr *nlh,
232 : const struct genl_family *family,
233 : struct nlattr *tb[], int maxtype,
234 : const struct nla_policy *policy,
235 : struct netlink_ext_ack *extack)
236 : {
237 : return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
238 : policy, NL_VALIDATE_STRICT, extack);
239 : }
240 :
241 : /**
242 : * genl_dump_check_consistent - check if sequence is consistent and advertise if not
243 : * @cb: netlink callback structure that stores the sequence number
244 : * @user_hdr: user header as returned from genlmsg_put()
245 : *
246 : * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
247 : * simpler to use with generic netlink.
248 : */
249 : static inline void genl_dump_check_consistent(struct netlink_callback *cb,
250 : void *user_hdr)
251 : {
252 : nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
253 : }
254 :
255 : /**
256 : * genlmsg_put_reply - Add generic netlink header to a reply message
257 : * @skb: socket buffer holding the message
258 : * @info: receiver info
259 : * @family: generic netlink family
260 : * @flags: netlink message flags
261 : * @cmd: generic netlink command
262 : *
263 : * Returns pointer to user specific header
264 : */
265 0 : static inline void *genlmsg_put_reply(struct sk_buff *skb,
266 : struct genl_info *info,
267 : const struct genl_family *family,
268 : int flags, u8 cmd)
269 : {
270 0 : return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
271 : flags, cmd);
272 : }
273 :
274 : /**
275 : * genlmsg_end - Finalize a generic netlink message
276 : * @skb: socket buffer the message is stored in
277 : * @hdr: user specific header
278 : */
279 2 : static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
280 : {
281 2 : nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
282 0 : }
283 :
284 : /**
285 : * genlmsg_cancel - Cancel construction of a generic netlink message
286 : * @skb: socket buffer the message is stored in
287 : * @hdr: generic netlink message header
288 : */
289 0 : static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
290 : {
291 0 : if (hdr)
292 0 : nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
293 : }
294 :
295 : /**
296 : * genlmsg_multicast_netns - multicast a netlink message to a specific netns
297 : * @family: the generic netlink family
298 : * @net: the net namespace
299 : * @skb: netlink message as socket buffer
300 : * @portid: own netlink portid to avoid sending to yourself
301 : * @group: offset of multicast group in groups array
302 : * @flags: allocation flags
303 : */
304 1 : static inline int genlmsg_multicast_netns(const struct genl_family *family,
305 : struct net *net, struct sk_buff *skb,
306 : u32 portid, unsigned int group, gfp_t flags)
307 : {
308 1 : if (WARN_ON_ONCE(group >= family->n_mcgrps))
309 : return -EINVAL;
310 1 : group = family->mcgrp_offset + group;
311 1 : return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
312 : }
313 :
314 : /**
315 : * genlmsg_multicast - multicast a netlink message to the default netns
316 : * @family: the generic netlink family
317 : * @skb: netlink message as socket buffer
318 : * @portid: own netlink portid to avoid sending to yourself
319 : * @group: offset of multicast group in groups array
320 : * @flags: allocation flags
321 : */
322 : static inline int genlmsg_multicast(const struct genl_family *family,
323 : struct sk_buff *skb, u32 portid,
324 : unsigned int group, gfp_t flags)
325 : {
326 : return genlmsg_multicast_netns(family, &init_net, skb,
327 : portid, group, flags);
328 : }
329 :
330 : /**
331 : * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
332 : * @family: the generic netlink family
333 : * @skb: netlink message as socket buffer
334 : * @portid: own netlink portid to avoid sending to yourself
335 : * @group: offset of multicast group in groups array
336 : * @flags: allocation flags
337 : *
338 : * This function must hold the RTNL or rcu_read_lock().
339 : */
340 : int genlmsg_multicast_allns(const struct genl_family *family,
341 : struct sk_buff *skb, u32 portid,
342 : unsigned int group, gfp_t flags);
343 :
344 : /**
345 : * genlmsg_unicast - unicast a netlink message
346 : * @skb: netlink message as socket buffer
347 : * @portid: netlink portid of the destination socket
348 : */
349 0 : static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
350 : {
351 0 : return nlmsg_unicast(net->genl_sock, skb, portid);
352 : }
353 :
354 : /**
355 : * genlmsg_reply - reply to a request
356 : * @skb: netlink message to be sent back
357 : * @info: receiver information
358 : */
359 0 : static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
360 : {
361 0 : return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
362 : }
363 :
364 : /**
365 : * gennlmsg_data - head of message payload
366 : * @gnlh: genetlink message header
367 : */
368 0 : static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
369 : {
370 0 : return ((unsigned char *) gnlh + GENL_HDRLEN);
371 : }
372 :
373 : /**
374 : * genlmsg_len - length of message payload
375 : * @gnlh: genetlink message header
376 : */
377 : static inline int genlmsg_len(const struct genlmsghdr *gnlh)
378 : {
379 : struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
380 : NLMSG_HDRLEN);
381 : return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
382 : }
383 :
384 : /**
385 : * genlmsg_msg_size - length of genetlink message not including padding
386 : * @payload: length of message payload
387 : */
388 0 : static inline int genlmsg_msg_size(int payload)
389 : {
390 0 : return GENL_HDRLEN + payload;
391 : }
392 :
393 : /**
394 : * genlmsg_total_size - length of genetlink message including padding
395 : * @payload: length of message payload
396 : */
397 0 : static inline int genlmsg_total_size(int payload)
398 : {
399 0 : return NLMSG_ALIGN(genlmsg_msg_size(payload));
400 : }
401 :
402 : /**
403 : * genlmsg_new - Allocate a new generic netlink message
404 : * @payload: size of the message payload
405 : * @flags: the type of memory to allocate.
406 : */
407 0 : static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
408 : {
409 0 : return nlmsg_new(genlmsg_total_size(payload), flags);
410 : }
411 :
412 : /**
413 : * genl_set_err - report error to genetlink broadcast listeners
414 : * @family: the generic netlink family
415 : * @net: the network namespace to report the error to
416 : * @portid: the PORTID of a process that we want to skip (if any)
417 : * @group: the broadcast group that will notice the error
418 : * (this is the offset of the multicast group in the groups array)
419 : * @code: error code, must be negative (as usual in kernelspace)
420 : *
421 : * This function returns the number of broadcast listeners that have set the
422 : * NETLINK_RECV_NO_ENOBUFS socket option.
423 : */
424 : static inline int genl_set_err(const struct genl_family *family,
425 : struct net *net, u32 portid,
426 : u32 group, int code)
427 : {
428 : if (WARN_ON_ONCE(group >= family->n_mcgrps))
429 : return -EINVAL;
430 : group = family->mcgrp_offset + group;
431 : return netlink_set_err(net->genl_sock, portid, group, code);
432 : }
433 :
434 : static inline int genl_has_listeners(const struct genl_family *family,
435 : struct net *net, unsigned int group)
436 : {
437 : if (WARN_ON_ONCE(group >= family->n_mcgrps))
438 : return -EINVAL;
439 : group = family->mcgrp_offset + group;
440 : return netlink_has_listeners(net->genl_sock, group);
441 : }
442 : #endif /* __NET_GENERIC_NETLINK_H */
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