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v5.9
  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 * @mcgrps: multicast groups used by this family
 39 * @n_mcgrps: number of multicast groups
 40 * @mcgrp_offset: starting number of multicast group IDs in this family
 41 *	(private)
 42 * @ops: the operations supported by this family
 43 * @n_ops: number of operations supported by this family
 44 */
 45struct genl_family {
 46	int			id;		/* private */
 47	unsigned int		hdrsize;
 48	char			name[GENL_NAMSIZ];
 49	unsigned int		version;
 50	unsigned int		maxattr;
 51	bool			netnsok;
 52	bool			parallel_ops;
 53	const struct nla_policy *policy;
 54	int			(*pre_doit)(const struct genl_ops *ops,
 55					    struct sk_buff *skb,
 56					    struct genl_info *info);
 57	void			(*post_doit)(const struct genl_ops *ops,
 58					     struct sk_buff *skb,
 59					     struct genl_info *info);
 
 
 
 60	const struct genl_ops *	ops;
 61	const struct genl_multicast_group *mcgrps;
 62	unsigned int		n_ops;
 63	unsigned int		n_mcgrps;
 64	unsigned int		mcgrp_offset;	/* private */
 65	struct module		*module;
 66};
 67
 
 
 68/**
 69 * struct genl_info - receiving information
 70 * @snd_seq: sending sequence number
 71 * @snd_portid: netlink portid of sender
 72 * @nlhdr: netlink message header
 73 * @genlhdr: generic netlink message header
 74 * @userhdr: user specific header
 75 * @attrs: netlink attributes
 76 * @_net: network namespace
 77 * @user_ptr: user pointers
 78 * @extack: extended ACK report struct
 79 */
 80struct genl_info {
 81	u32			snd_seq;
 82	u32			snd_portid;
 83	struct nlmsghdr *	nlhdr;
 84	struct genlmsghdr *	genlhdr;
 85	void *			userhdr;
 86	struct nlattr **	attrs;
 87	possible_net_t		_net;
 88	void *			user_ptr[2];
 89	struct netlink_ext_ack *extack;
 90};
 91
 92static inline struct net *genl_info_net(struct genl_info *info)
 93{
 94	return read_pnet(&info->_net);
 95}
 96
 97static inline void genl_info_net_set(struct genl_info *info, struct net *net)
 98{
 99	write_pnet(&info->_net, net);
100}
101
102#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
103
104static inline int genl_err_attr(struct genl_info *info, int err,
105				const struct nlattr *attr)
106{
107	info->extack->bad_attr = attr;
108
109	return err;
110}
111
112enum genl_validate_flags {
113	GENL_DONT_VALIDATE_STRICT		= BIT(0),
114	GENL_DONT_VALIDATE_DUMP			= BIT(1),
115	GENL_DONT_VALIDATE_DUMP_STRICT		= BIT(2),
116};
117
118/**
119 * struct genl_info - info that is available during dumpit op call
120 * @family: generic netlink family - for internal genl code usage
121 * @ops: generic netlink ops - for internal genl code usage
122 * @attrs: netlink attributes
123 */
124struct genl_dumpit_info {
125	const struct genl_family *family;
126	const struct genl_ops *ops;
127	struct nlattr **attrs;
128};
129
130static inline const struct genl_dumpit_info *
131genl_dumpit_info(struct netlink_callback *cb)
132{
133	return cb->data;
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 * @validate: validation flags from enum genl_validate_flags
142 * @doit: standard command callback
143 * @start: start callback for dumps
144 * @dumpit: callback for dumpers
145 * @done: completion callback for dumps
146 */
147struct genl_ops {
148	int		       (*doit)(struct sk_buff *skb,
149				       struct genl_info *info);
150	int		       (*start)(struct netlink_callback *cb);
151	int		       (*dumpit)(struct sk_buff *skb,
152					 struct netlink_callback *cb);
153	int		       (*done)(struct netlink_callback *cb);
154	u8			cmd;
155	u8			internal_flags;
156	u8			flags;
157	u8			validate;
158};
159
160int genl_register_family(struct genl_family *family);
161int genl_unregister_family(const struct genl_family *family);
162void genl_notify(const struct genl_family *family, struct sk_buff *skb,
163		 struct genl_info *info, u32 group, gfp_t flags);
164
165void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
166		  const struct genl_family *family, int flags, u8 cmd);
167
168/**
169 * genlmsg_nlhdr - Obtain netlink header from user specified header
170 * @user_hdr: user header as returned from genlmsg_put()
171 *
172 * Returns pointer to netlink header.
173 */
174static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
175{
176	return (struct nlmsghdr *)((char *)user_hdr -
177				   GENL_HDRLEN -
178				   NLMSG_HDRLEN);
179}
180
181/**
182 * genlmsg_parse_deprecated - parse attributes of a genetlink message
183 * @nlh: netlink message header
184 * @family: genetlink message family
185 * @tb: destination array with maxtype+1 elements
186 * @maxtype: maximum attribute type to be expected
187 * @policy: validation policy
188 * @extack: extended ACK report struct
189 */
190static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
191					   const struct genl_family *family,
192					   struct nlattr *tb[], int maxtype,
193					   const struct nla_policy *policy,
194					   struct netlink_ext_ack *extack)
195{
196	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
197			     policy, NL_VALIDATE_LIBERAL, extack);
198}
199
200/**
201 * genlmsg_parse - parse attributes of a genetlink message
202 * @nlh: netlink message header
203 * @family: genetlink message family
204 * @tb: destination array with maxtype+1 elements
205 * @maxtype: maximum attribute type to be expected
206 * @policy: validation policy
207 * @extack: extended ACK report struct
208 */
209static inline int genlmsg_parse(const struct nlmsghdr *nlh,
210				const struct genl_family *family,
211				struct nlattr *tb[], int maxtype,
212				const struct nla_policy *policy,
213				struct netlink_ext_ack *extack)
214{
215	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
216			     policy, NL_VALIDATE_STRICT, extack);
217}
218
219/**
220 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
221 * @cb: netlink callback structure that stores the sequence number
222 * @user_hdr: user header as returned from genlmsg_put()
223 *
224 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
225 * simpler to use with generic netlink.
226 */
227static inline void genl_dump_check_consistent(struct netlink_callback *cb,
228					      void *user_hdr)
229{
230	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
231}
232
233/**
234 * genlmsg_put_reply - Add generic netlink header to a reply message
235 * @skb: socket buffer holding the message
236 * @info: receiver info
237 * @family: generic netlink family
238 * @flags: netlink message flags
239 * @cmd: generic netlink command
240 *
241 * Returns pointer to user specific header
242 */
243static inline void *genlmsg_put_reply(struct sk_buff *skb,
244				      struct genl_info *info,
245				      const struct genl_family *family,
246				      int flags, u8 cmd)
247{
248	return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
249			   flags, cmd);
250}
251
252/**
253 * genlmsg_end - Finalize a generic netlink message
254 * @skb: socket buffer the message is stored in
255 * @hdr: user specific header
256 */
257static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
258{
259	nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
260}
261
262/**
263 * genlmsg_cancel - Cancel construction of a generic netlink message
264 * @skb: socket buffer the message is stored in
265 * @hdr: generic netlink message header
266 */
267static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
268{
269	if (hdr)
270		nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
271}
272
273/**
274 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
275 * @family: the generic netlink family
276 * @net: the net namespace
277 * @skb: netlink message as socket buffer
278 * @portid: own netlink portid to avoid sending to yourself
279 * @group: offset of multicast group in groups array
280 * @flags: allocation flags
281 */
282static inline int genlmsg_multicast_netns(const struct genl_family *family,
283					  struct net *net, struct sk_buff *skb,
284					  u32 portid, unsigned int group, gfp_t flags)
285{
286	if (WARN_ON_ONCE(group >= family->n_mcgrps))
287		return -EINVAL;
288	group = family->mcgrp_offset + group;
289	return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
290}
291
292/**
293 * genlmsg_multicast - multicast a netlink message to the default netns
294 * @family: the generic netlink family
295 * @skb: netlink message as socket buffer
296 * @portid: own netlink portid to avoid sending to yourself
297 * @group: offset of multicast group in groups array
298 * @flags: allocation flags
299 */
300static inline int genlmsg_multicast(const struct genl_family *family,
301				    struct sk_buff *skb, u32 portid,
302				    unsigned int group, gfp_t flags)
303{
304	return genlmsg_multicast_netns(family, &init_net, skb,
305				       portid, group, flags);
306}
307
308/**
309 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
310 * @family: the generic netlink family
311 * @skb: netlink message as socket buffer
312 * @portid: own netlink portid to avoid sending to yourself
313 * @group: offset of multicast group in groups array
314 * @flags: allocation flags
315 *
316 * This function must hold the RTNL or rcu_read_lock().
317 */
318int genlmsg_multicast_allns(const struct genl_family *family,
319			    struct sk_buff *skb, u32 portid,
320			    unsigned int group, gfp_t flags);
321
322/**
323 * genlmsg_unicast - unicast a netlink message
324 * @skb: netlink message as socket buffer
325 * @portid: netlink portid of the destination socket
326 */
327static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
328{
329	return nlmsg_unicast(net->genl_sock, skb, portid);
330}
331
332/**
333 * genlmsg_reply - reply to a request
334 * @skb: netlink message to be sent back
335 * @info: receiver information
336 */
337static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
338{
339	return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
340}
341
342/**
343 * gennlmsg_data - head of message payload
344 * @gnlh: genetlink message header
345 */
346static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
347{
348	return ((unsigned char *) gnlh + GENL_HDRLEN);
349}
350
351/**
352 * genlmsg_len - length of message payload
353 * @gnlh: genetlink message header
354 */
355static inline int genlmsg_len(const struct genlmsghdr *gnlh)
356{
357	struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
358							NLMSG_HDRLEN);
359	return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
360}
361
362/**
363 * genlmsg_msg_size - length of genetlink message not including padding
364 * @payload: length of message payload
365 */
366static inline int genlmsg_msg_size(int payload)
367{
368	return GENL_HDRLEN + payload;
369}
370
371/**
372 * genlmsg_total_size - length of genetlink message including padding
373 * @payload: length of message payload
374 */
375static inline int genlmsg_total_size(int payload)
376{
377	return NLMSG_ALIGN(genlmsg_msg_size(payload));
378}
379
380/**
381 * genlmsg_new - Allocate a new generic netlink message
382 * @payload: size of the message payload
383 * @flags: the type of memory to allocate.
384 */
385static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
386{
387	return nlmsg_new(genlmsg_total_size(payload), flags);
388}
389
390/**
391 * genl_set_err - report error to genetlink broadcast listeners
392 * @family: the generic netlink family
393 * @net: the network namespace to report the error to
394 * @portid: the PORTID of a process that we want to skip (if any)
395 * @group: the broadcast group that will notice the error
396 * 	(this is the offset of the multicast group in the groups array)
397 * @code: error code, must be negative (as usual in kernelspace)
398 *
399 * This function returns the number of broadcast listeners that have set the
400 * NETLINK_RECV_NO_ENOBUFS socket option.
401 */
402static inline int genl_set_err(const struct genl_family *family,
403			       struct net *net, u32 portid,
404			       u32 group, int code)
405{
406	if (WARN_ON_ONCE(group >= family->n_mcgrps))
407		return -EINVAL;
408	group = family->mcgrp_offset + group;
409	return netlink_set_err(net->genl_sock, portid, group, code);
410}
411
412static inline int genl_has_listeners(const struct genl_family *family,
413				     struct net *net, unsigned int group)
414{
415	if (WARN_ON_ONCE(group >= family->n_mcgrps))
416		return -EINVAL;
417	group = family->mcgrp_offset + group;
418	return netlink_has_listeners(net->genl_sock, group);
419}
420#endif	/* __NET_GENERIC_NETLINK_H */
v5.4
  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 */