1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_GENERIC_NETLINK_H
3 #define __NET_GENERIC_NETLINK_H
5 #include <linux/genetlink.h>
6 #include <net/netlink.h>
7 #include <net/net_namespace.h>
9 #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
12 * struct genl_multicast_group - generic netlink multicast group
13 * @name: name of the multicast group, names are per-family
15 struct genl_multicast_group
{
16 char name
[GENL_NAMSIZ
];
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
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
49 * @ops: the operations supported by this family
50 * @n_ops: number of operations supported by this family
55 char name
[GENL_NAMSIZ
];
60 const struct nla_policy
*policy
;
61 int (*pre_doit
)(const struct genl_ops
*ops
,
63 struct genl_info
*info
);
64 void (*post_doit
)(const struct genl_ops
*ops
,
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
;
73 unsigned int n_mcgrps
;
74 unsigned int mcgrp_offset
; /* private */
75 struct module
*module
;
78 struct nlattr
**genl_family_attrbuf(const struct genl_family
*family
);
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
95 struct nlmsghdr
* nlhdr
;
96 struct genlmsghdr
* genlhdr
;
98 struct nlattr
** attrs
;
101 struct netlink_ext_ack
*extack
;
104 static inline struct net
*genl_info_net(struct genl_info
*info
)
106 return read_pnet(&info
->_net
);
109 static inline void genl_info_net_set(struct genl_info
*info
, struct net
*net
)
111 write_pnet(&info
->_net
, net
);
114 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
116 static inline int genl_err_attr(struct genl_info
*info
, int err
,
117 const struct nlattr
*attr
)
119 info
->extack
->bad_attr
= attr
;
124 enum 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),
131 * struct genl_ops - generic netlink operations
132 * @cmd: command identifier
133 * @internal_flags: flags used by the family
135 * @doit: standard command callback
136 * @start: start callback for dumps
137 * @dumpit: callback for dumpers
138 * @done: completion callback for dumps
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
);
153 int genl_register_family(struct genl_family
*family
);
154 int genl_unregister_family(const struct genl_family
*family
);
155 void genl_notify(const struct genl_family
*family
, struct sk_buff
*skb
,
156 struct genl_info
*info
, u32 group
, gfp_t flags
);
158 void *genlmsg_put(struct sk_buff
*skb
, u32 portid
, u32 seq
,
159 const struct genl_family
*family
, int flags
, u8 cmd
);
162 * genlmsg_nlhdr - Obtain netlink header from user specified header
163 * @user_hdr: user header as returned from genlmsg_put()
165 * Returns pointer to netlink header.
167 static inline struct nlmsghdr
*genlmsg_nlhdr(void *user_hdr
)
169 return (struct nlmsghdr
*)((char *)user_hdr
-
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
183 static 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
)
189 return __nlmsg_parse(nlh
, family
->hdrsize
+ GENL_HDRLEN
, tb
, maxtype
,
190 policy
, NL_VALIDATE_LIBERAL
, extack
);
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
202 static 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
)
208 return __nlmsg_parse(nlh
, family
->hdrsize
+ GENL_HDRLEN
, tb
, maxtype
,
209 policy
, NL_VALIDATE_STRICT
, extack
);
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()
217 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
218 * simpler to use with generic netlink.
220 static inline void genl_dump_check_consistent(struct netlink_callback
*cb
,
223 nl_dump_check_consistent(cb
, genlmsg_nlhdr(user_hdr
));
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
234 * Returns pointer to user specific header
236 static inline void *genlmsg_put_reply(struct sk_buff
*skb
,
237 struct genl_info
*info
,
238 const struct genl_family
*family
,
241 return genlmsg_put(skb
, info
->snd_portid
, info
->snd_seq
, family
,
246 * genlmsg_end - Finalize a generic netlink message
247 * @skb: socket buffer the message is stored in
248 * @hdr: user specific header
250 static inline void genlmsg_end(struct sk_buff
*skb
, void *hdr
)
252 nlmsg_end(skb
, hdr
- GENL_HDRLEN
- NLMSG_HDRLEN
);
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
260 static inline void genlmsg_cancel(struct sk_buff
*skb
, void *hdr
)
263 nlmsg_cancel(skb
, hdr
- GENL_HDRLEN
- NLMSG_HDRLEN
);
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
275 static 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
)
279 if (WARN_ON_ONCE(group
>= family
->n_mcgrps
))
281 group
= family
->mcgrp_offset
+ group
;
282 return nlmsg_multicast(net
->genl_sock
, skb
, portid
, group
, flags
);
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
293 static inline int genlmsg_multicast(const struct genl_family
*family
,
294 struct sk_buff
*skb
, u32 portid
,
295 unsigned int group
, gfp_t flags
)
297 return genlmsg_multicast_netns(family
, &init_net
, skb
,
298 portid
, group
, flags
);
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
309 * This function must hold the RTNL or rcu_read_lock().
311 int genlmsg_multicast_allns(const struct genl_family
*family
,
312 struct sk_buff
*skb
, u32 portid
,
313 unsigned int group
, gfp_t flags
);
316 * genlmsg_unicast - unicast a netlink message
317 * @skb: netlink message as socket buffer
318 * @portid: netlink portid of the destination socket
320 static inline int genlmsg_unicast(struct net
*net
, struct sk_buff
*skb
, u32 portid
)
322 return nlmsg_unicast(net
->genl_sock
, skb
, portid
);
326 * genlmsg_reply - reply to a request
327 * @skb: netlink message to be sent back
328 * @info: receiver information
330 static inline int genlmsg_reply(struct sk_buff
*skb
, struct genl_info
*info
)
332 return genlmsg_unicast(genl_info_net(info
), skb
, info
->snd_portid
);
336 * gennlmsg_data - head of message payload
337 * @gnlh: genetlink message header
339 static inline void *genlmsg_data(const struct genlmsghdr
*gnlh
)
341 return ((unsigned char *) gnlh
+ GENL_HDRLEN
);
345 * genlmsg_len - length of message payload
346 * @gnlh: genetlink message header
348 static inline int genlmsg_len(const struct genlmsghdr
*gnlh
)
350 struct nlmsghdr
*nlh
= (struct nlmsghdr
*)((unsigned char *)gnlh
-
352 return (nlh
->nlmsg_len
- GENL_HDRLEN
- NLMSG_HDRLEN
);
356 * genlmsg_msg_size - length of genetlink message not including padding
357 * @payload: length of message payload
359 static inline int genlmsg_msg_size(int payload
)
361 return GENL_HDRLEN
+ payload
;
365 * genlmsg_total_size - length of genetlink message including padding
366 * @payload: length of message payload
368 static inline int genlmsg_total_size(int payload
)
370 return NLMSG_ALIGN(genlmsg_msg_size(payload
));
374 * genlmsg_new - Allocate a new generic netlink message
375 * @payload: size of the message payload
376 * @flags: the type of memory to allocate.
378 static inline struct sk_buff
*genlmsg_new(size_t payload
, gfp_t flags
)
380 return nlmsg_new(genlmsg_total_size(payload
), flags
);
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)
392 * This function returns the number of broadcast listeners that have set the
393 * NETLINK_RECV_NO_ENOBUFS socket option.
395 static inline int genl_set_err(const struct genl_family
*family
,
396 struct net
*net
, u32 portid
,
399 if (WARN_ON_ONCE(group
>= family
->n_mcgrps
))
401 group
= family
->mcgrp_offset
+ group
;
402 return netlink_set_err(net
->genl_sock
, portid
, group
, code
);
405 static inline int genl_has_listeners(const struct genl_family
*family
,
406 struct net
*net
, unsigned int group
)
408 if (WARN_ON_ONCE(group
>= family
->n_mcgrps
))
410 group
= family
->mcgrp_offset
+ group
;
411 return netlink_has_listeners(net
->genl_sock
, group
);
413 #endif /* __NET_GENERIC_NETLINK_H */