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 * @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
42 * @ops: the operations supported by this family
43 * @n_ops: number of operations supported by this family
48 char name[GENL_NAMSIZ];
53 const struct nla_policy *policy;
54 int (*pre_doit)(const struct genl_ops *ops,
56 struct genl_info *info);
57 void (*post_doit)(const struct genl_ops *ops,
59 struct genl_info *info);
60 const struct genl_ops * ops;
61 const struct genl_multicast_group *mcgrps;
63 unsigned int n_mcgrps;
64 unsigned int mcgrp_offset; /* private */
65 struct module *module;
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
83 struct nlmsghdr * nlhdr;
84 struct genlmsghdr * genlhdr;
86 struct nlattr ** attrs;
89 struct netlink_ext_ack *extack;
92 static inline struct net *genl_info_net(struct genl_info *info)
94 return read_pnet(&info->_net);
97 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
99 write_pnet(&info->_net, net);
102 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
104 static inline int genl_err_attr(struct genl_info *info, int err,
105 const struct nlattr *attr)
107 info->extack->bad_attr = attr;
112 enum 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),
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
124 struct genl_dumpit_info {
125 const struct genl_family *family;
126 const struct genl_ops *ops;
127 struct nlattr **attrs;
130 static inline const struct genl_dumpit_info *
131 genl_dumpit_info(struct netlink_callback *cb)
137 * struct genl_ops - generic netlink operations
138 * @cmd: command identifier
139 * @internal_flags: flags used by the family
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
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);
160 int genl_register_family(struct genl_family *family);
161 int genl_unregister_family(const struct genl_family *family);
162 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
163 struct genl_info *info, u32 group, gfp_t flags);
165 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
166 const struct genl_family *family, int flags, u8 cmd);
169 * genlmsg_nlhdr - Obtain netlink header from user specified header
170 * @user_hdr: user header as returned from genlmsg_put()
172 * Returns pointer to netlink header.
174 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
176 return (struct nlmsghdr *)((char *)user_hdr -
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
190 static 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)
196 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
197 policy, NL_VALIDATE_LIBERAL, extack);
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
209 static 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)
215 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
216 policy, NL_VALIDATE_STRICT, extack);
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()
224 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
225 * simpler to use with generic netlink.
227 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
230 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
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
241 * Returns pointer to user specific header
243 static inline void *genlmsg_put_reply(struct sk_buff *skb,
244 struct genl_info *info,
245 const struct genl_family *family,
248 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
253 * genlmsg_end - Finalize a generic netlink message
254 * @skb: socket buffer the message is stored in
255 * @hdr: user specific header
257 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
259 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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
267 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
270 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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
282 static 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)
286 if (WARN_ON_ONCE(group >= family->n_mcgrps))
288 group = family->mcgrp_offset + group;
289 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
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
300 static inline int genlmsg_multicast(const struct genl_family *family,
301 struct sk_buff *skb, u32 portid,
302 unsigned int group, gfp_t flags)
304 return genlmsg_multicast_netns(family, &init_net, skb,
305 portid, group, flags);
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
316 * This function must hold the RTNL or rcu_read_lock().
318 int genlmsg_multicast_allns(const struct genl_family *family,
319 struct sk_buff *skb, u32 portid,
320 unsigned int group, gfp_t flags);
323 * genlmsg_unicast - unicast a netlink message
324 * @skb: netlink message as socket buffer
325 * @portid: netlink portid of the destination socket
327 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
329 return nlmsg_unicast(net->genl_sock, skb, portid);
333 * genlmsg_reply - reply to a request
334 * @skb: netlink message to be sent back
335 * @info: receiver information
337 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
339 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
343 * gennlmsg_data - head of message payload
344 * @gnlh: genetlink message header
346 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
348 return ((unsigned char *) gnlh + GENL_HDRLEN);
352 * genlmsg_len - length of message payload
353 * @gnlh: genetlink message header
355 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
357 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
359 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
363 * genlmsg_msg_size - length of genetlink message not including padding
364 * @payload: length of message payload
366 static inline int genlmsg_msg_size(int payload)
368 return GENL_HDRLEN + payload;
372 * genlmsg_total_size - length of genetlink message including padding
373 * @payload: length of message payload
375 static inline int genlmsg_total_size(int payload)
377 return NLMSG_ALIGN(genlmsg_msg_size(payload));
381 * genlmsg_new - Allocate a new generic netlink message
382 * @payload: size of the message payload
383 * @flags: the type of memory to allocate.
385 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
387 return nlmsg_new(genlmsg_total_size(payload), flags);
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)
399 * This function returns the number of broadcast listeners that have set the
400 * NETLINK_RECV_NO_ENOBUFS socket option.
402 static inline int genl_set_err(const struct genl_family *family,
403 struct net *net, u32 portid,
406 if (WARN_ON_ONCE(group >= family->n_mcgrps))
408 group = family->mcgrp_offset + group;
409 return netlink_set_err(net->genl_sock, portid, group, code);
412 static inline int genl_has_listeners(const struct genl_family *family,
413 struct net *net, unsigned int group)
415 if (WARN_ON_ONCE(group >= family->n_mcgrps))
417 group = family->mcgrp_offset + group;
418 return netlink_has_listeners(net->genl_sock, group);
420 #endif /* __NET_GENERIC_NETLINK_H */