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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 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
15 */
16struct genl_multicast_group {
17 char name[GENL_NAMSIZ];
18 u8 flags;
19};
20
21struct genl_split_ops;
22struct genl_info;
23
24/**
25 * struct genl_family - generic netlink family
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 * @module: pointer to the owning module (set to THIS_MODULE)
40 * @mcgrps: multicast groups used by this family
41 * @n_mcgrps: number of multicast groups
42 * @resv_start_op: first operation for which reserved fields of the header
43 * can be validated and policies are required (see below);
44 * new families should leave this field at zero
45 * @ops: the operations supported by this family
46 * @n_ops: number of operations supported by this family
47 * @small_ops: the small-struct operations supported by this family
48 * @n_small_ops: number of small-struct operations supported by this family
49 * @split_ops: the split do/dump form of operation definition
50 * @n_split_ops: number of entries in @split_ops, not that with split do/dump
51 * ops the number of entries is not the same as number of commands
52 *
53 * Attribute policies (the combination of @policy and @maxattr fields)
54 * can be attached at the family level or at the operation level.
55 * If both are present the per-operation policy takes precedence.
56 * For operations before @resv_start_op lack of policy means that the core
57 * will perform no attribute parsing or validation. For newer operations
58 * if policy is not provided core will reject all TLV attributes.
59 */
60struct genl_family {
61 unsigned int hdrsize;
62 char name[GENL_NAMSIZ];
63 unsigned int version;
64 unsigned int maxattr;
65 u8 netnsok:1;
66 u8 parallel_ops:1;
67 u8 n_ops;
68 u8 n_small_ops;
69 u8 n_split_ops;
70 u8 n_mcgrps;
71 u8 resv_start_op;
72 const struct nla_policy *policy;
73 int (*pre_doit)(const struct genl_split_ops *ops,
74 struct sk_buff *skb,
75 struct genl_info *info);
76 void (*post_doit)(const struct genl_split_ops *ops,
77 struct sk_buff *skb,
78 struct genl_info *info);
79 const struct genl_ops * ops;
80 const struct genl_small_ops *small_ops;
81 const struct genl_split_ops *split_ops;
82 const struct genl_multicast_group *mcgrps;
83 struct module *module;
84
85/* private: internal use only */
86 /* protocol family identifier */
87 int id;
88 /* starting number of multicast group IDs in this family */
89 unsigned int mcgrp_offset;
90};
91
92/**
93 * struct genl_info - receiving information
94 * @snd_seq: sending sequence number
95 * @snd_portid: netlink portid of sender
96 * @nlhdr: netlink message header
97 * @genlhdr: generic netlink message header
98 * @userhdr: user specific header
99 * @attrs: netlink attributes
100 * @_net: network namespace
101 * @user_ptr: user pointers
102 * @extack: extended ACK report struct
103 */
104struct genl_info {
105 u32 snd_seq;
106 u32 snd_portid;
107 struct nlmsghdr * nlhdr;
108 struct genlmsghdr * genlhdr;
109 void * userhdr;
110 struct nlattr ** attrs;
111 possible_net_t _net;
112 void * user_ptr[2];
113 struct netlink_ext_ack *extack;
114};
115
116static inline struct net *genl_info_net(struct genl_info *info)
117{
118 return read_pnet(&info->_net);
119}
120
121static inline void genl_info_net_set(struct genl_info *info, struct net *net)
122{
123 write_pnet(&info->_net, net);
124}
125
126#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
127
128#define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
129 NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)
130
131/* Report that a root attribute is missing */
132#define GENL_REQ_ATTR_CHECK(info, attr) ({ \
133 struct genl_info *__info = (info); \
134 \
135 NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
136})
137
138enum genl_validate_flags {
139 GENL_DONT_VALIDATE_STRICT = BIT(0),
140 GENL_DONT_VALIDATE_DUMP = BIT(1),
141 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
142};
143
144/**
145 * struct genl_small_ops - generic netlink operations (small version)
146 * @cmd: command identifier
147 * @internal_flags: flags used by the family
148 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
149 * @validate: validation flags from enum genl_validate_flags
150 * @doit: standard command callback
151 * @dumpit: callback for dumpers
152 *
153 * This is a cut-down version of struct genl_ops for users who don't need
154 * most of the ancillary infra and want to save space.
155 */
156struct genl_small_ops {
157 int (*doit)(struct sk_buff *skb, struct genl_info *info);
158 int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
159 u8 cmd;
160 u8 internal_flags;
161 u8 flags;
162 u8 validate;
163};
164
165/**
166 * struct genl_ops - generic netlink operations
167 * @cmd: command identifier
168 * @internal_flags: flags used by the family
169 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
170 * @maxattr: maximum number of attributes supported
171 * @policy: netlink policy (takes precedence over family policy)
172 * @validate: validation flags from enum genl_validate_flags
173 * @doit: standard command callback
174 * @start: start callback for dumps
175 * @dumpit: callback for dumpers
176 * @done: completion callback for dumps
177 */
178struct genl_ops {
179 int (*doit)(struct sk_buff *skb,
180 struct genl_info *info);
181 int (*start)(struct netlink_callback *cb);
182 int (*dumpit)(struct sk_buff *skb,
183 struct netlink_callback *cb);
184 int (*done)(struct netlink_callback *cb);
185 const struct nla_policy *policy;
186 unsigned int maxattr;
187 u8 cmd;
188 u8 internal_flags;
189 u8 flags;
190 u8 validate;
191};
192
193/**
194 * struct genl_split_ops - generic netlink operations (do/dump split version)
195 * @cmd: command identifier
196 * @internal_flags: flags used by the family
197 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
198 * @validate: validation flags from enum genl_validate_flags
199 * @policy: netlink policy (takes precedence over family policy)
200 * @maxattr: maximum number of attributes supported
201 *
202 * Do callbacks:
203 * @pre_doit: called before an operation's @doit callback, it may
204 * do additional, common, filtering and return an error
205 * @doit: standard command callback
206 * @post_doit: called after an operation's @doit callback, it may
207 * undo operations done by pre_doit, for example release locks
208 *
209 * Dump callbacks:
210 * @start: start callback for dumps
211 * @dumpit: callback for dumpers
212 * @done: completion callback for dumps
213 *
214 * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
215 * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
216 * Exactly one of those flags must be set.
217 */
218struct genl_split_ops {
219 union {
220 struct {
221 int (*pre_doit)(const struct genl_split_ops *ops,
222 struct sk_buff *skb,
223 struct genl_info *info);
224 int (*doit)(struct sk_buff *skb,
225 struct genl_info *info);
226 void (*post_doit)(const struct genl_split_ops *ops,
227 struct sk_buff *skb,
228 struct genl_info *info);
229 };
230 struct {
231 int (*start)(struct netlink_callback *cb);
232 int (*dumpit)(struct sk_buff *skb,
233 struct netlink_callback *cb);
234 int (*done)(struct netlink_callback *cb);
235 };
236 };
237 const struct nla_policy *policy;
238 unsigned int maxattr;
239 u8 cmd;
240 u8 internal_flags;
241 u8 flags;
242 u8 validate;
243};
244
245/**
246 * struct genl_dumpit_info - info that is available during dumpit op call
247 * @family: generic netlink family - for internal genl code usage
248 * @op: generic netlink ops - for internal genl code usage
249 * @attrs: netlink attributes
250 */
251struct genl_dumpit_info {
252 const struct genl_family *family;
253 struct genl_split_ops op;
254 struct nlattr **attrs;
255};
256
257static inline const struct genl_dumpit_info *
258genl_dumpit_info(struct netlink_callback *cb)
259{
260 return cb->data;
261}
262
263int genl_register_family(struct genl_family *family);
264int genl_unregister_family(const struct genl_family *family);
265void genl_notify(const struct genl_family *family, struct sk_buff *skb,
266 struct genl_info *info, u32 group, gfp_t flags);
267
268void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
269 const struct genl_family *family, int flags, u8 cmd);
270
271/**
272 * genlmsg_nlhdr - Obtain netlink header from user specified header
273 * @user_hdr: user header as returned from genlmsg_put()
274 *
275 * Returns pointer to netlink header.
276 */
277static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
278{
279 return (struct nlmsghdr *)((char *)user_hdr -
280 GENL_HDRLEN -
281 NLMSG_HDRLEN);
282}
283
284/**
285 * genlmsg_parse_deprecated - parse attributes of a genetlink message
286 * @nlh: netlink message header
287 * @family: genetlink message family
288 * @tb: destination array with maxtype+1 elements
289 * @maxtype: maximum attribute type to be expected
290 * @policy: validation policy
291 * @extack: extended ACK report struct
292 */
293static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
294 const struct genl_family *family,
295 struct nlattr *tb[], int maxtype,
296 const struct nla_policy *policy,
297 struct netlink_ext_ack *extack)
298{
299 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
300 policy, NL_VALIDATE_LIBERAL, extack);
301}
302
303/**
304 * genlmsg_parse - parse attributes of a genetlink message
305 * @nlh: netlink message header
306 * @family: genetlink message family
307 * @tb: destination array with maxtype+1 elements
308 * @maxtype: maximum attribute type to be expected
309 * @policy: validation policy
310 * @extack: extended ACK report struct
311 */
312static inline int genlmsg_parse(const struct nlmsghdr *nlh,
313 const struct genl_family *family,
314 struct nlattr *tb[], int maxtype,
315 const struct nla_policy *policy,
316 struct netlink_ext_ack *extack)
317{
318 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
319 policy, NL_VALIDATE_STRICT, extack);
320}
321
322/**
323 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
324 * @cb: netlink callback structure that stores the sequence number
325 * @user_hdr: user header as returned from genlmsg_put()
326 *
327 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
328 * simpler to use with generic netlink.
329 */
330static inline void genl_dump_check_consistent(struct netlink_callback *cb,
331 void *user_hdr)
332{
333 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
334}
335
336/**
337 * genlmsg_put_reply - Add generic netlink header to a reply message
338 * @skb: socket buffer holding the message
339 * @info: receiver info
340 * @family: generic netlink family
341 * @flags: netlink message flags
342 * @cmd: generic netlink command
343 *
344 * Returns pointer to user specific header
345 */
346static inline void *genlmsg_put_reply(struct sk_buff *skb,
347 struct genl_info *info,
348 const struct genl_family *family,
349 int flags, u8 cmd)
350{
351 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
352 flags, cmd);
353}
354
355/**
356 * genlmsg_end - Finalize a generic netlink message
357 * @skb: socket buffer the message is stored in
358 * @hdr: user specific header
359 */
360static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
361{
362 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
363}
364
365/**
366 * genlmsg_cancel - Cancel construction of a generic netlink message
367 * @skb: socket buffer the message is stored in
368 * @hdr: generic netlink message header
369 */
370static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
371{
372 if (hdr)
373 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
374}
375
376/**
377 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
378 * @family: the generic netlink family
379 * @net: the net namespace
380 * @skb: netlink message as socket buffer
381 * @portid: own netlink portid to avoid sending to yourself
382 * @group: offset of multicast group in groups array
383 * @flags: allocation flags
384 */
385static inline int genlmsg_multicast_netns(const struct genl_family *family,
386 struct net *net, struct sk_buff *skb,
387 u32 portid, unsigned int group, gfp_t flags)
388{
389 if (WARN_ON_ONCE(group >= family->n_mcgrps))
390 return -EINVAL;
391 group = family->mcgrp_offset + group;
392 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
393}
394
395/**
396 * genlmsg_multicast - multicast a netlink message to the default netns
397 * @family: the generic netlink family
398 * @skb: netlink message as socket buffer
399 * @portid: own netlink portid to avoid sending to yourself
400 * @group: offset of multicast group in groups array
401 * @flags: allocation flags
402 */
403static inline int genlmsg_multicast(const struct genl_family *family,
404 struct sk_buff *skb, u32 portid,
405 unsigned int group, gfp_t flags)
406{
407 return genlmsg_multicast_netns(family, &init_net, skb,
408 portid, group, flags);
409}
410
411/**
412 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
413 * @family: the generic netlink family
414 * @skb: netlink message as socket buffer
415 * @portid: own netlink portid to avoid sending to yourself
416 * @group: offset of multicast group in groups array
417 * @flags: allocation flags
418 *
419 * This function must hold the RTNL or rcu_read_lock().
420 */
421int genlmsg_multicast_allns(const struct genl_family *family,
422 struct sk_buff *skb, u32 portid,
423 unsigned int group, gfp_t flags);
424
425/**
426 * genlmsg_unicast - unicast a netlink message
427 * @net: network namespace to look up @portid in
428 * @skb: netlink message as socket buffer
429 * @portid: netlink portid of the destination socket
430 */
431static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
432{
433 return nlmsg_unicast(net->genl_sock, skb, portid);
434}
435
436/**
437 * genlmsg_reply - reply to a request
438 * @skb: netlink message to be sent back
439 * @info: receiver information
440 */
441static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
442{
443 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
444}
445
446/**
447 * genlmsg_data - head of message payload
448 * @gnlh: genetlink message header
449 */
450static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
451{
452 return ((unsigned char *) gnlh + GENL_HDRLEN);
453}
454
455/**
456 * genlmsg_len - length of message payload
457 * @gnlh: genetlink message header
458 */
459static inline int genlmsg_len(const struct genlmsghdr *gnlh)
460{
461 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
462 NLMSG_HDRLEN);
463 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
464}
465
466/**
467 * genlmsg_msg_size - length of genetlink message not including padding
468 * @payload: length of message payload
469 */
470static inline int genlmsg_msg_size(int payload)
471{
472 return GENL_HDRLEN + payload;
473}
474
475/**
476 * genlmsg_total_size - length of genetlink message including padding
477 * @payload: length of message payload
478 */
479static inline int genlmsg_total_size(int payload)
480{
481 return NLMSG_ALIGN(genlmsg_msg_size(payload));
482}
483
484/**
485 * genlmsg_new - Allocate a new generic netlink message
486 * @payload: size of the message payload
487 * @flags: the type of memory to allocate.
488 */
489static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
490{
491 return nlmsg_new(genlmsg_total_size(payload), flags);
492}
493
494/**
495 * genl_set_err - report error to genetlink broadcast listeners
496 * @family: the generic netlink family
497 * @net: the network namespace to report the error to
498 * @portid: the PORTID of a process that we want to skip (if any)
499 * @group: the broadcast group that will notice the error
500 * (this is the offset of the multicast group in the groups array)
501 * @code: error code, must be negative (as usual in kernelspace)
502 *
503 * This function returns the number of broadcast listeners that have set the
504 * NETLINK_RECV_NO_ENOBUFS socket option.
505 */
506static inline int genl_set_err(const struct genl_family *family,
507 struct net *net, u32 portid,
508 u32 group, int code)
509{
510 if (WARN_ON_ONCE(group >= family->n_mcgrps))
511 return -EINVAL;
512 group = family->mcgrp_offset + group;
513 return netlink_set_err(net->genl_sock, portid, group, code);
514}
515
516static inline int genl_has_listeners(const struct genl_family *family,
517 struct net *net, unsigned int group)
518{
519 if (WARN_ON_ONCE(group >= family->n_mcgrps))
520 return -EINVAL;
521 group = family->mcgrp_offset + group;
522 return netlink_has_listeners(net->genl_sock, group);
523}
524#endif /* __NET_GENERIC_NETLINK_H */
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 */
15struct genl_multicast_group {
16 char name[GENL_NAMSIZ];
17};
18
19struct genl_ops;
20struct genl_info;
21
22/**
23 * struct genl_family - generic netlink family
24 * @id: protocol family identifier (private)
25 * @hdrsize: length of user specific header in bytes
26 * @name: name of family
27 * @version: protocol version
28 * @maxattr: maximum number of attributes supported
29 * @policy: netlink policy
30 * @netnsok: set to true if the family can handle network
31 * namespaces and should be presented in all of them
32 * @parallel_ops: operations can be called in parallel and aren't
33 * synchronized by the core genetlink code
34 * @pre_doit: called before an operation's doit callback, it may
35 * do additional, common, filtering and return an error
36 * @post_doit: called after an operation's doit callback, it may
37 * undo operations done by pre_doit, for example release locks
38 * @mcast_bind: a socket bound to the given multicast group (which
39 * is given as the offset into the groups array)
40 * @mcast_unbind: a socket was unbound from the given multicast group.
41 * Note that unbind() will not be called symmetrically if the
42 * generic netlink family is removed while there are still open
43 * sockets.
44 * @attrbuf: buffer to store parsed attributes (private)
45 * @mcgrps: multicast groups used by this family
46 * @n_mcgrps: number of multicast groups
47 * @mcgrp_offset: starting number of multicast group IDs in this family
48 * (private)
49 * @ops: the operations supported by this family
50 * @n_ops: number of operations supported by this family
51 */
52struct genl_family {
53 int id; /* private */
54 unsigned int hdrsize;
55 char name[GENL_NAMSIZ];
56 unsigned int version;
57 unsigned int maxattr;
58 bool netnsok;
59 bool parallel_ops;
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 int (*mcast_bind)(struct net *net, int group);
68 void (*mcast_unbind)(struct net *net, int group);
69 struct nlattr ** attrbuf; /* private */
70 const struct genl_ops * ops;
71 const struct genl_multicast_group *mcgrps;
72 unsigned int n_ops;
73 unsigned int n_mcgrps;
74 unsigned int mcgrp_offset; /* private */
75 struct module *module;
76};
77
78struct nlattr **genl_family_attrbuf(const struct genl_family *family);
79
80/**
81 * struct genl_info - receiving information
82 * @snd_seq: sending sequence number
83 * @snd_portid: netlink portid of sender
84 * @nlhdr: netlink message header
85 * @genlhdr: generic netlink message header
86 * @userhdr: user specific header
87 * @attrs: netlink attributes
88 * @_net: network namespace
89 * @user_ptr: user pointers
90 * @extack: extended ACK report struct
91 */
92struct genl_info {
93 u32 snd_seq;
94 u32 snd_portid;
95 struct nlmsghdr * nlhdr;
96 struct genlmsghdr * genlhdr;
97 void * userhdr;
98 struct nlattr ** attrs;
99 possible_net_t _net;
100 void * user_ptr[2];
101 struct netlink_ext_ack *extack;
102};
103
104static inline struct net *genl_info_net(struct genl_info *info)
105{
106 return read_pnet(&info->_net);
107}
108
109static inline void genl_info_net_set(struct genl_info *info, struct net *net)
110{
111 write_pnet(&info->_net, net);
112}
113
114#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
115
116static inline int genl_err_attr(struct genl_info *info, int err,
117 const struct nlattr *attr)
118{
119 info->extack->bad_attr = attr;
120
121 return err;
122}
123
124enum genl_validate_flags {
125 GENL_DONT_VALIDATE_STRICT = BIT(0),
126 GENL_DONT_VALIDATE_DUMP = BIT(1),
127 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
128};
129
130/**
131 * struct genl_ops - generic netlink operations
132 * @cmd: command identifier
133 * @internal_flags: flags used by the family
134 * @flags: flags
135 * @doit: standard command callback
136 * @start: start callback for dumps
137 * @dumpit: callback for dumpers
138 * @done: completion callback for dumps
139 */
140struct genl_ops {
141 int (*doit)(struct sk_buff *skb,
142 struct genl_info *info);
143 int (*start)(struct netlink_callback *cb);
144 int (*dumpit)(struct sk_buff *skb,
145 struct netlink_callback *cb);
146 int (*done)(struct netlink_callback *cb);
147 u8 cmd;
148 u8 internal_flags;
149 u8 flags;
150 u8 validate;
151};
152
153int genl_register_family(struct genl_family *family);
154int genl_unregister_family(const struct genl_family *family);
155void genl_notify(const struct genl_family *family, struct sk_buff *skb,
156 struct genl_info *info, u32 group, gfp_t flags);
157
158void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
159 const struct genl_family *family, int flags, u8 cmd);
160
161/**
162 * genlmsg_nlhdr - Obtain netlink header from user specified header
163 * @user_hdr: user header as returned from genlmsg_put()
164 *
165 * Returns pointer to netlink header.
166 */
167static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
168{
169 return (struct nlmsghdr *)((char *)user_hdr -
170 GENL_HDRLEN -
171 NLMSG_HDRLEN);
172}
173
174/**
175 * genlmsg_parse_deprecated - parse attributes of a genetlink message
176 * @nlh: netlink message header
177 * @family: genetlink message family
178 * @tb: destination array with maxtype+1 elements
179 * @maxtype: maximum attribute type to be expected
180 * @policy: validation policy
181 * @extack: extended ACK report struct
182 */
183static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
184 const struct genl_family *family,
185 struct nlattr *tb[], int maxtype,
186 const struct nla_policy *policy,
187 struct netlink_ext_ack *extack)
188{
189 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
190 policy, NL_VALIDATE_LIBERAL, extack);
191}
192
193/**
194 * genlmsg_parse - parse attributes of a genetlink message
195 * @nlh: netlink message header
196 * @family: genetlink message family
197 * @tb: destination array with maxtype+1 elements
198 * @maxtype: maximum attribute type to be expected
199 * @policy: validation policy
200 * @extack: extended ACK report struct
201 */
202static inline int genlmsg_parse(const struct nlmsghdr *nlh,
203 const struct genl_family *family,
204 struct nlattr *tb[], int maxtype,
205 const struct nla_policy *policy,
206 struct netlink_ext_ack *extack)
207{
208 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
209 policy, NL_VALIDATE_STRICT, extack);
210}
211
212/**
213 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
214 * @cb: netlink callback structure that stores the sequence number
215 * @user_hdr: user header as returned from genlmsg_put()
216 *
217 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
218 * simpler to use with generic netlink.
219 */
220static inline void genl_dump_check_consistent(struct netlink_callback *cb,
221 void *user_hdr)
222{
223 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
224}
225
226/**
227 * genlmsg_put_reply - Add generic netlink header to a reply message
228 * @skb: socket buffer holding the message
229 * @info: receiver info
230 * @family: generic netlink family
231 * @flags: netlink message flags
232 * @cmd: generic netlink command
233 *
234 * Returns pointer to user specific header
235 */
236static inline void *genlmsg_put_reply(struct sk_buff *skb,
237 struct genl_info *info,
238 const struct genl_family *family,
239 int flags, u8 cmd)
240{
241 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
242 flags, cmd);
243}
244
245/**
246 * genlmsg_end - Finalize a generic netlink message
247 * @skb: socket buffer the message is stored in
248 * @hdr: user specific header
249 */
250static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
251{
252 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
253}
254
255/**
256 * genlmsg_cancel - Cancel construction of a generic netlink message
257 * @skb: socket buffer the message is stored in
258 * @hdr: generic netlink message header
259 */
260static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
261{
262 if (hdr)
263 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
264}
265
266/**
267 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
268 * @family: the generic netlink family
269 * @net: the net namespace
270 * @skb: netlink message as socket buffer
271 * @portid: own netlink portid to avoid sending to yourself
272 * @group: offset of multicast group in groups array
273 * @flags: allocation flags
274 */
275static inline int genlmsg_multicast_netns(const struct genl_family *family,
276 struct net *net, struct sk_buff *skb,
277 u32 portid, unsigned int group, gfp_t flags)
278{
279 if (WARN_ON_ONCE(group >= family->n_mcgrps))
280 return -EINVAL;
281 group = family->mcgrp_offset + group;
282 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
283}
284
285/**
286 * genlmsg_multicast - multicast a netlink message to the default netns
287 * @family: the generic netlink family
288 * @skb: netlink message as socket buffer
289 * @portid: own netlink portid to avoid sending to yourself
290 * @group: offset of multicast group in groups array
291 * @flags: allocation flags
292 */
293static inline int genlmsg_multicast(const struct genl_family *family,
294 struct sk_buff *skb, u32 portid,
295 unsigned int group, gfp_t flags)
296{
297 return genlmsg_multicast_netns(family, &init_net, skb,
298 portid, group, flags);
299}
300
301/**
302 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
303 * @family: the generic netlink family
304 * @skb: netlink message as socket buffer
305 * @portid: own netlink portid to avoid sending to yourself
306 * @group: offset of multicast group in groups array
307 * @flags: allocation flags
308 *
309 * This function must hold the RTNL or rcu_read_lock().
310 */
311int genlmsg_multicast_allns(const struct genl_family *family,
312 struct sk_buff *skb, u32 portid,
313 unsigned int group, gfp_t flags);
314
315/**
316 * genlmsg_unicast - unicast a netlink message
317 * @skb: netlink message as socket buffer
318 * @portid: netlink portid of the destination socket
319 */
320static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
321{
322 return nlmsg_unicast(net->genl_sock, skb, portid);
323}
324
325/**
326 * genlmsg_reply - reply to a request
327 * @skb: netlink message to be sent back
328 * @info: receiver information
329 */
330static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
331{
332 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
333}
334
335/**
336 * gennlmsg_data - head of message payload
337 * @gnlh: genetlink message header
338 */
339static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
340{
341 return ((unsigned char *) gnlh + GENL_HDRLEN);
342}
343
344/**
345 * genlmsg_len - length of message payload
346 * @gnlh: genetlink message header
347 */
348static inline int genlmsg_len(const struct genlmsghdr *gnlh)
349{
350 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
351 NLMSG_HDRLEN);
352 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
353}
354
355/**
356 * genlmsg_msg_size - length of genetlink message not including padding
357 * @payload: length of message payload
358 */
359static inline int genlmsg_msg_size(int payload)
360{
361 return GENL_HDRLEN + payload;
362}
363
364/**
365 * genlmsg_total_size - length of genetlink message including padding
366 * @payload: length of message payload
367 */
368static inline int genlmsg_total_size(int payload)
369{
370 return NLMSG_ALIGN(genlmsg_msg_size(payload));
371}
372
373/**
374 * genlmsg_new - Allocate a new generic netlink message
375 * @payload: size of the message payload
376 * @flags: the type of memory to allocate.
377 */
378static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
379{
380 return nlmsg_new(genlmsg_total_size(payload), flags);
381}
382
383/**
384 * genl_set_err - report error to genetlink broadcast listeners
385 * @family: the generic netlink family
386 * @net: the network namespace to report the error to
387 * @portid: the PORTID of a process that we want to skip (if any)
388 * @group: the broadcast group that will notice the error
389 * (this is the offset of the multicast group in the groups array)
390 * @code: error code, must be negative (as usual in kernelspace)
391 *
392 * This function returns the number of broadcast listeners that have set the
393 * NETLINK_RECV_NO_ENOBUFS socket option.
394 */
395static inline int genl_set_err(const struct genl_family *family,
396 struct net *net, u32 portid,
397 u32 group, int code)
398{
399 if (WARN_ON_ONCE(group >= family->n_mcgrps))
400 return -EINVAL;
401 group = family->mcgrp_offset + group;
402 return netlink_set_err(net->genl_sock, portid, group, code);
403}
404
405static inline int genl_has_listeners(const struct genl_family *family,
406 struct net *net, unsigned int group)
407{
408 if (WARN_ON_ONCE(group >= family->n_mcgrps))
409 return -EINVAL;
410 group = family->mcgrp_offset + group;
411 return netlink_has_listeners(net->genl_sock, group);
412}
413#endif /* __NET_GENERIC_NETLINK_H */