xref: /linux/include/net/genetlink.h (revision ec8c17e5ecb4a5a74069687ccb6d2cfe1851302e)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_GENERIC_NETLINK_H
3 #define __NET_GENERIC_NETLINK_H
4 
5 #include <linux/net.h>
6 #include <net/netlink.h>
7 #include <net/net_namespace.h>
8 #include <uapi/linux/genetlink.h>
9 
10 #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
11 
12 /* Non-parallel generic netlink requests are serialized by a global lock. */
13 void genl_lock(void);
14 void genl_unlock(void);
15 
16 #define MODULE_ALIAS_GENL_FAMILY(family) \
17  MODULE_ALIAS_NET_PF_PROTO_NAME(PF_NETLINK, NETLINK_GENERIC, "-family-" family)
18 
19 /* Binding to multicast group requires %CAP_NET_ADMIN */
20 #define GENL_MCAST_CAP_NET_ADMIN	BIT(0)
21 /* Binding to multicast group requires %CAP_SYS_ADMIN */
22 #define GENL_MCAST_CAP_SYS_ADMIN	BIT(1)
23 
24 /**
25  * struct genl_multicast_group - generic netlink multicast group
26  * @name: name of the multicast group, names are per-family
27  * @flags: GENL_MCAST_* flags
28  */
29 struct genl_multicast_group {
30 	char			name[GENL_NAMSIZ];
31 	u8			flags;
32 };
33 
34 struct genl_split_ops;
35 struct genl_info;
36 
37 /**
38  * struct genl_family - generic netlink family
39  * @hdrsize: length of user specific header in bytes
40  * @name: name of family
41  * @version: protocol version
42  * @maxattr: maximum number of attributes supported
43  * @policy: netlink policy
44  * @netnsok: set to true if the family can handle network
45  *	namespaces and should be presented in all of them
46  * @parallel_ops: operations can be called in parallel and aren't
47  *	synchronized by the core genetlink code
48  * @pre_doit: called before an operation's doit callback, it may
49  *	do additional, common, filtering and return an error
50  * @post_doit: called after an operation's doit callback, it may
51  *	undo operations done by pre_doit, for example release locks
52  * @bind: called when family multicast group is added to a netlink socket
53  * @unbind: called when family multicast group is removed from a netlink socket
54  * @module: pointer to the owning module (set to THIS_MODULE)
55  * @mcgrps: multicast groups used by this family
56  * @n_mcgrps: number of multicast groups
57  * @resv_start_op: first operation for which reserved fields of the header
58  *	can be validated and policies are required (see below);
59  *	new families should leave this field at zero
60  * @ops: the operations supported by this family
61  * @n_ops: number of operations supported by this family
62  * @small_ops: the small-struct operations supported by this family
63  * @n_small_ops: number of small-struct operations supported by this family
64  * @split_ops: the split do/dump form of operation definition
65  * @n_split_ops: number of entries in @split_ops, not that with split do/dump
66  *	ops the number of entries is not the same as number of commands
67  * @sock_priv_size: the size of per-socket private memory
68  * @sock_priv_init: the per-socket private memory initializer
69  * @sock_priv_destroy: the per-socket private memory destructor
70  *
71  * Attribute policies (the combination of @policy and @maxattr fields)
72  * can be attached at the family level or at the operation level.
73  * If both are present the per-operation policy takes precedence.
74  * For operations before @resv_start_op lack of policy means that the core
75  * will perform no attribute parsing or validation. For newer operations
76  * if policy is not provided core will reject all TLV attributes.
77  */
78 struct genl_family {
79 	unsigned int		hdrsize;
80 	char			name[GENL_NAMSIZ];
81 	unsigned int		version;
82 	unsigned int		maxattr;
83 	u8			netnsok:1;
84 	u8			parallel_ops:1;
85 	u8			n_ops;
86 	u8			n_small_ops;
87 	u8			n_split_ops;
88 	u8			n_mcgrps;
89 	u8			resv_start_op;
90 	const struct nla_policy *policy;
91 	int			(*pre_doit)(const struct genl_split_ops *ops,
92 					    struct sk_buff *skb,
93 					    struct genl_info *info);
94 	void			(*post_doit)(const struct genl_split_ops *ops,
95 					     struct sk_buff *skb,
96 					     struct genl_info *info);
97 	int			(*bind)(int mcgrp);
98 	void			(*unbind)(int mcgrp);
99 	const struct genl_ops *	ops;
100 	const struct genl_small_ops *small_ops;
101 	const struct genl_split_ops *split_ops;
102 	const struct genl_multicast_group *mcgrps;
103 	struct module		*module;
104 
105 	size_t			sock_priv_size;
106 	void			(*sock_priv_init)(void *priv);
107 	void			(*sock_priv_destroy)(void *priv);
108 
109 /* private: internal use only */
110 	/* protocol family identifier */
111 	int			id;
112 	/* starting number of multicast group IDs in this family */
113 	unsigned int		mcgrp_offset;
114 	/* list of per-socket privs */
115 	struct xarray		*sock_privs;
116 };
117 
118 /**
119  * struct genl_info - receiving information
120  * @snd_seq: sending sequence number
121  * @snd_portid: netlink portid of sender
122  * @family: generic netlink family
123  * @nlhdr: netlink message header
124  * @genlhdr: generic netlink message header
125  * @attrs: netlink attributes
126  * @_net: network namespace
127  * @ctx: storage space for the use by the family
128  * @user_ptr: user pointers (deprecated, use ctx instead)
129  * @extack: extended ACK report struct
130  */
131 struct genl_info {
132 	u32			snd_seq;
133 	u32			snd_portid;
134 	const struct genl_family *family;
135 	const struct nlmsghdr *	nlhdr;
136 	struct genlmsghdr *	genlhdr;
137 	struct nlattr **	attrs;
138 	possible_net_t		_net;
139 	union {
140 		u8		ctx[NETLINK_CTX_SIZE];
141 		void *		user_ptr[2];
142 	};
143 	struct netlink_ext_ack *extack;
144 };
145 
genl_info_net(const struct genl_info * info)146 static inline struct net *genl_info_net(const struct genl_info *info)
147 {
148 	return read_pnet(&info->_net);
149 }
150 
genl_info_net_set(struct genl_info * info,struct net * net)151 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
152 {
153 	write_pnet(&info->_net, net);
154 }
155 
genl_info_userhdr(const struct genl_info * info)156 static inline void *genl_info_userhdr(const struct genl_info *info)
157 {
158 	return (u8 *)info->genlhdr + GENL_HDRLEN;
159 }
160 
161 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
162 
163 #define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
164 	NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)
165 
166 /* Report that a root attribute is missing */
167 #define GENL_REQ_ATTR_CHECK(info, attr) ({				\
168 	const struct genl_info *__info = (info);			\
169 									\
170 	NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
171 })
172 
173 enum genl_validate_flags {
174 	GENL_DONT_VALIDATE_STRICT		= BIT(0),
175 	GENL_DONT_VALIDATE_DUMP			= BIT(1),
176 	GENL_DONT_VALIDATE_DUMP_STRICT		= BIT(2),
177 };
178 
179 /**
180  * struct genl_small_ops - generic netlink operations (small version)
181  * @cmd: command identifier
182  * @internal_flags: flags used by the family
183  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
184  * @validate: validation flags from enum genl_validate_flags
185  * @doit: standard command callback
186  * @dumpit: callback for dumpers
187  *
188  * This is a cut-down version of struct genl_ops for users who don't need
189  * most of the ancillary infra and want to save space.
190  */
191 struct genl_small_ops {
192 	int	(*doit)(struct sk_buff *skb, struct genl_info *info);
193 	int	(*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
194 	u8	cmd;
195 	u8	internal_flags;
196 	u8	flags;
197 	u8	validate;
198 };
199 
200 /**
201  * struct genl_ops - generic netlink operations
202  * @cmd: command identifier
203  * @internal_flags: flags used by the family
204  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
205  * @maxattr: maximum number of attributes supported
206  * @policy: netlink policy (takes precedence over family policy)
207  * @validate: validation flags from enum genl_validate_flags
208  * @doit: standard command callback
209  * @start: start callback for dumps
210  * @dumpit: callback for dumpers
211  * @done: completion callback for dumps
212  */
213 struct genl_ops {
214 	int		       (*doit)(struct sk_buff *skb,
215 				       struct genl_info *info);
216 	int		       (*start)(struct netlink_callback *cb);
217 	int		       (*dumpit)(struct sk_buff *skb,
218 					 struct netlink_callback *cb);
219 	int		       (*done)(struct netlink_callback *cb);
220 	const struct nla_policy *policy;
221 	unsigned int		maxattr;
222 	u8			cmd;
223 	u8			internal_flags;
224 	u8			flags;
225 	u8			validate;
226 };
227 
228 /**
229  * struct genl_split_ops - generic netlink operations (do/dump split version)
230  * @cmd: command identifier
231  * @internal_flags: flags used by the family
232  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
233  * @validate: validation flags from enum genl_validate_flags
234  * @policy: netlink policy (takes precedence over family policy)
235  * @maxattr: maximum number of attributes supported
236  *
237  * Do callbacks:
238  * @pre_doit: called before an operation's @doit callback, it may
239  *	do additional, common, filtering and return an error
240  * @doit: standard command callback
241  * @post_doit: called after an operation's @doit callback, it may
242  *	undo operations done by pre_doit, for example release locks
243  *
244  * Dump callbacks:
245  * @start: start callback for dumps
246  * @dumpit: callback for dumpers
247  * @done: completion callback for dumps
248  *
249  * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
250  * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
251  * Exactly one of those flags must be set.
252  */
253 struct genl_split_ops {
254 	union {
255 		struct {
256 			int (*pre_doit)(const struct genl_split_ops *ops,
257 					struct sk_buff *skb,
258 					struct genl_info *info);
259 			int (*doit)(struct sk_buff *skb,
260 				    struct genl_info *info);
261 			void (*post_doit)(const struct genl_split_ops *ops,
262 					  struct sk_buff *skb,
263 					  struct genl_info *info);
264 		};
265 		struct {
266 			int (*start)(struct netlink_callback *cb);
267 			int (*dumpit)(struct sk_buff *skb,
268 				      struct netlink_callback *cb);
269 			int (*done)(struct netlink_callback *cb);
270 		};
271 	};
272 	const struct nla_policy *policy;
273 	unsigned int		maxattr;
274 	u8			cmd;
275 	u8			internal_flags;
276 	u8			flags;
277 	u8			validate;
278 };
279 
280 /**
281  * struct genl_dumpit_info - info that is available during dumpit op call
282  * @op: generic netlink ops - for internal genl code usage
283  * @attrs: netlink attributes
284  * @info: struct genl_info describing the request
285  */
286 struct genl_dumpit_info {
287 	struct genl_split_ops op;
288 	struct genl_info info;
289 };
290 
291 static inline const struct genl_dumpit_info *
genl_dumpit_info(struct netlink_callback * cb)292 genl_dumpit_info(struct netlink_callback *cb)
293 {
294 	return cb->data;
295 }
296 
297 static inline const struct genl_info *
genl_info_dump(struct netlink_callback * cb)298 genl_info_dump(struct netlink_callback *cb)
299 {
300 	return &genl_dumpit_info(cb)->info;
301 }
302 
303 /**
304  * genl_info_init_ntf() - initialize genl_info for notifications
305  * @info:   genl_info struct to set up
306  * @family: pointer to the genetlink family
307  * @cmd:    command to be used in the notification
308  *
309  * Initialize a locally declared struct genl_info to pass to various APIs.
310  * Intended to be used when creating notifications.
311  */
312 static inline void
genl_info_init_ntf(struct genl_info * info,const struct genl_family * family,u8 cmd)313 genl_info_init_ntf(struct genl_info *info, const struct genl_family *family,
314 		   u8 cmd)
315 {
316 	struct genlmsghdr *hdr = (void *) &info->user_ptr[0];
317 
318 	memset(info, 0, sizeof(*info));
319 	info->family = family;
320 	info->genlhdr = hdr;
321 	hdr->cmd = cmd;
322 }
323 
genl_info_is_ntf(const struct genl_info * info)324 static inline bool genl_info_is_ntf(const struct genl_info *info)
325 {
326 	return !info->nlhdr;
327 }
328 
329 void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk);
330 void *genl_sk_priv_get(struct genl_family *family, struct sock *sk);
331 int genl_register_family(struct genl_family *family);
332 int genl_unregister_family(const struct genl_family *family);
333 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
334 		 struct genl_info *info, u32 group, gfp_t flags);
335 
336 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
337 		  const struct genl_family *family, int flags, u8 cmd);
338 
339 static inline void *
__genlmsg_iput(struct sk_buff * skb,const struct genl_info * info,int flags)340 __genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags)
341 {
342 	return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family,
343 			   flags, info->genlhdr->cmd);
344 }
345 
346 /**
347  * genlmsg_iput - start genetlink message based on genl_info
348  * @skb: skb in which message header will be placed
349  * @info: genl_info as provided to do/dump handlers
350  *
351  * Convenience wrapper which starts a genetlink message based on
352  * information in user request. @info should be either the struct passed
353  * by genetlink core to do/dump handlers (when constructing replies to
354  * such requests) or a struct initialized by genl_info_init_ntf()
355  * when constructing notifications.
356  *
357  * Returns pointer to new genetlink header.
358  */
359 static inline void *
genlmsg_iput(struct sk_buff * skb,const struct genl_info * info)360 genlmsg_iput(struct sk_buff *skb, const struct genl_info *info)
361 {
362 	return __genlmsg_iput(skb, info, 0);
363 }
364 
365 /**
366  * genlmsg_nlhdr - Obtain netlink header from user specified header
367  * @user_hdr: user header as returned from genlmsg_put()
368  *
369  * Returns pointer to netlink header.
370  */
genlmsg_nlhdr(void * user_hdr)371 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
372 {
373 	return (struct nlmsghdr *)((char *)user_hdr -
374 				   GENL_HDRLEN -
375 				   NLMSG_HDRLEN);
376 }
377 
378 /**
379  * genlmsg_parse_deprecated - parse attributes of a genetlink message
380  * @nlh: netlink message header
381  * @family: genetlink message family
382  * @tb: destination array with maxtype+1 elements
383  * @maxtype: maximum attribute type to be expected
384  * @policy: validation policy
385  * @extack: extended ACK report struct
386  */
genlmsg_parse_deprecated(const struct nlmsghdr * nlh,const struct genl_family * family,struct nlattr * tb[],int maxtype,const struct nla_policy * policy,struct netlink_ext_ack * extack)387 static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
388 					   const struct genl_family *family,
389 					   struct nlattr *tb[], int maxtype,
390 					   const struct nla_policy *policy,
391 					   struct netlink_ext_ack *extack)
392 {
393 	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
394 			     policy, NL_VALIDATE_LIBERAL, extack);
395 }
396 
397 /**
398  * genlmsg_parse - parse attributes of a genetlink message
399  * @nlh: netlink message header
400  * @family: genetlink message family
401  * @tb: destination array with maxtype+1 elements
402  * @maxtype: maximum attribute type to be expected
403  * @policy: validation policy
404  * @extack: extended ACK report struct
405  */
genlmsg_parse(const struct nlmsghdr * nlh,const struct genl_family * family,struct nlattr * tb[],int maxtype,const struct nla_policy * policy,struct netlink_ext_ack * extack)406 static inline int genlmsg_parse(const struct nlmsghdr *nlh,
407 				const struct genl_family *family,
408 				struct nlattr *tb[], int maxtype,
409 				const struct nla_policy *policy,
410 				struct netlink_ext_ack *extack)
411 {
412 	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
413 			     policy, NL_VALIDATE_STRICT, extack);
414 }
415 
416 /**
417  * genl_dump_check_consistent - check if sequence is consistent and advertise if not
418  * @cb: netlink callback structure that stores the sequence number
419  * @user_hdr: user header as returned from genlmsg_put()
420  *
421  * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
422  * simpler to use with generic netlink.
423  */
genl_dump_check_consistent(struct netlink_callback * cb,void * user_hdr)424 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
425 					      void *user_hdr)
426 {
427 	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
428 }
429 
430 /**
431  * genlmsg_put_reply - Add generic netlink header to a reply message
432  * @skb: socket buffer holding the message
433  * @info: receiver info
434  * @family: generic netlink family
435  * @flags: netlink message flags
436  * @cmd: generic netlink command
437  *
438  * Returns pointer to user specific header
439  */
genlmsg_put_reply(struct sk_buff * skb,struct genl_info * info,const struct genl_family * family,int flags,u8 cmd)440 static inline void *genlmsg_put_reply(struct sk_buff *skb,
441 				      struct genl_info *info,
442 				      const struct genl_family *family,
443 				      int flags, u8 cmd)
444 {
445 	return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
446 			   flags, cmd);
447 }
448 
449 /**
450  * genlmsg_end - Finalize a generic netlink message
451  * @skb: socket buffer the message is stored in
452  * @hdr: user specific header
453  */
genlmsg_end(struct sk_buff * skb,void * hdr)454 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
455 {
456 	nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
457 }
458 
459 /**
460  * genlmsg_cancel - Cancel construction of a generic netlink message
461  * @skb: socket buffer the message is stored in
462  * @hdr: generic netlink message header
463  */
genlmsg_cancel(struct sk_buff * skb,void * hdr)464 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
465 {
466 	if (hdr)
467 		nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
468 }
469 
470 /**
471  * genlmsg_multicast_netns_filtered - multicast a netlink message
472  *				      to a specific netns with filter
473  *				      function
474  * @family: the generic netlink family
475  * @net: the net namespace
476  * @skb: netlink message as socket buffer
477  * @portid: own netlink portid to avoid sending to yourself
478  * @group: offset of multicast group in groups array
479  * @flags: allocation flags
480  * @filter: filter function
481  * @filter_data: filter function private data
482  *
483  * Return: 0 on success, negative error code for failure.
484  */
485 static inline int
genlmsg_multicast_netns_filtered(const struct genl_family * family,struct net * net,struct sk_buff * skb,u32 portid,unsigned int group,gfp_t flags,netlink_filter_fn filter,void * filter_data)486 genlmsg_multicast_netns_filtered(const struct genl_family *family,
487 				 struct net *net, struct sk_buff *skb,
488 				 u32 portid, unsigned int group, gfp_t flags,
489 				 netlink_filter_fn filter,
490 				 void *filter_data)
491 {
492 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
493 		return -EINVAL;
494 	group = family->mcgrp_offset + group;
495 	return nlmsg_multicast_filtered(net->genl_sock, skb, portid, group,
496 					flags, filter, filter_data);
497 }
498 
499 /**
500  * genlmsg_multicast_netns - multicast a netlink message to a specific netns
501  * @family: the generic netlink family
502  * @net: the net namespace
503  * @skb: netlink message as socket buffer
504  * @portid: own netlink portid to avoid sending to yourself
505  * @group: offset of multicast group in groups array
506  * @flags: allocation flags
507  */
genlmsg_multicast_netns(const struct genl_family * family,struct net * net,struct sk_buff * skb,u32 portid,unsigned int group,gfp_t flags)508 static inline int genlmsg_multicast_netns(const struct genl_family *family,
509 					  struct net *net, struct sk_buff *skb,
510 					  u32 portid, unsigned int group, gfp_t flags)
511 {
512 	return genlmsg_multicast_netns_filtered(family, net, skb, portid,
513 						group, flags, NULL, NULL);
514 }
515 
516 /**
517  * genlmsg_multicast - multicast a netlink message to the default netns
518  * @family: the generic netlink family
519  * @skb: netlink message as socket buffer
520  * @portid: own netlink portid to avoid sending to yourself
521  * @group: offset of multicast group in groups array
522  * @flags: allocation flags
523  */
genlmsg_multicast(const struct genl_family * family,struct sk_buff * skb,u32 portid,unsigned int group,gfp_t flags)524 static inline int genlmsg_multicast(const struct genl_family *family,
525 				    struct sk_buff *skb, u32 portid,
526 				    unsigned int group, gfp_t flags)
527 {
528 	return genlmsg_multicast_netns(family, &init_net, skb,
529 				       portid, group, flags);
530 }
531 
532 /**
533  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
534  * @family: the generic netlink family
535  * @skb: netlink message as socket buffer
536  * @portid: own netlink portid to avoid sending to yourself
537  * @group: offset of multicast group in groups array
538  *
539  * This function must hold the RTNL or rcu_read_lock().
540  */
541 int genlmsg_multicast_allns(const struct genl_family *family,
542 			    struct sk_buff *skb, u32 portid,
543 			    unsigned int group);
544 
545 /**
546  * genlmsg_unicast - unicast a netlink message
547  * @net: network namespace to look up @portid in
548  * @skb: netlink message as socket buffer
549  * @portid: netlink portid of the destination socket
550  */
genlmsg_unicast(struct net * net,struct sk_buff * skb,u32 portid)551 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
552 {
553 	return nlmsg_unicast(net->genl_sock, skb, portid);
554 }
555 
556 /**
557  * genlmsg_reply - reply to a request
558  * @skb: netlink message to be sent back
559  * @info: receiver information
560  */
genlmsg_reply(struct sk_buff * skb,struct genl_info * info)561 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
562 {
563 	return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
564 }
565 
566 /**
567  * genlmsg_data - head of message payload
568  * @gnlh: genetlink message header
569  */
genlmsg_data(const struct genlmsghdr * gnlh)570 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
571 {
572 	return ((unsigned char *) gnlh + GENL_HDRLEN);
573 }
574 
575 /**
576  * genlmsg_len - length of message payload
577  * @gnlh: genetlink message header
578  */
genlmsg_len(const struct genlmsghdr * gnlh)579 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
580 {
581 	struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
582 							NLMSG_HDRLEN);
583 	return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
584 }
585 
586 /**
587  * genlmsg_msg_size - length of genetlink message not including padding
588  * @payload: length of message payload
589  */
genlmsg_msg_size(int payload)590 static inline int genlmsg_msg_size(int payload)
591 {
592 	return GENL_HDRLEN + payload;
593 }
594 
595 /**
596  * genlmsg_total_size - length of genetlink message including padding
597  * @payload: length of message payload
598  */
genlmsg_total_size(int payload)599 static inline int genlmsg_total_size(int payload)
600 {
601 	return NLMSG_ALIGN(genlmsg_msg_size(payload));
602 }
603 
604 /**
605  * genlmsg_new - Allocate a new generic netlink message
606  * @payload: size of the message payload
607  * @flags: the type of memory to allocate.
608  */
genlmsg_new(size_t payload,gfp_t flags)609 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
610 {
611 	return nlmsg_new(genlmsg_total_size(payload), flags);
612 }
613 
614 /**
615  * genl_set_err - report error to genetlink broadcast listeners
616  * @family: the generic netlink family
617  * @net: the network namespace to report the error to
618  * @portid: the PORTID of a process that we want to skip (if any)
619  * @group: the broadcast group that will notice the error
620  * 	(this is the offset of the multicast group in the groups array)
621  * @code: error code, must be negative (as usual in kernelspace)
622  *
623  * This function returns the number of broadcast listeners that have set the
624  * NETLINK_RECV_NO_ENOBUFS socket option.
625  */
genl_set_err(const struct genl_family * family,struct net * net,u32 portid,u32 group,int code)626 static inline int genl_set_err(const struct genl_family *family,
627 			       struct net *net, u32 portid,
628 			       u32 group, int code)
629 {
630 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
631 		return -EINVAL;
632 	group = family->mcgrp_offset + group;
633 	return netlink_set_err(net->genl_sock, portid, group, code);
634 }
635 
genl_has_listeners(const struct genl_family * family,struct net * net,unsigned int group)636 static inline int genl_has_listeners(const struct genl_family *family,
637 				     struct net *net, unsigned int group)
638 {
639 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
640 		return -EINVAL;
641 	group = family->mcgrp_offset + group;
642 	return netlink_has_listeners(net->genl_sock, group);
643 }
644 #endif	/* __NET_GENERIC_NETLINK_H */
645