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
14 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
16 struct genl_multicast_group {
17 char name[GENL_NAMSIZ];
21 struct genl_split_ops;
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
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.
62 char name[GENL_NAMSIZ];
72 const struct nla_policy *policy;
73 int (*pre_doit)(const struct genl_split_ops *ops,
75 struct genl_info *info);
76 void (*post_doit)(const struct genl_split_ops *ops,
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;
85 /* private: internal use only */
86 /* protocol family identifier */
88 /* starting number of multicast group IDs in this family */
89 unsigned int mcgrp_offset;
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
107 struct nlmsghdr * nlhdr;
108 struct genlmsghdr * genlhdr;
110 struct nlattr ** attrs;
113 struct netlink_ext_ack *extack;
116 static inline struct net *genl_info_net(struct genl_info *info)
118 return read_pnet(&info->_net);
121 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
123 write_pnet(&info->_net, net);
126 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
128 #define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
129 NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)
131 /* Report that a root attribute is missing */
132 #define GENL_REQ_ATTR_CHECK(info, attr) ({ \
133 struct genl_info *__info = (info); \
135 NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
138 enum 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),
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
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.
156 struct 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);
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
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;
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
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
210 * @start: start callback for dumps
211 * @dumpit: callback for dumpers
212 * @done: completion callback for dumps
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.
218 struct genl_split_ops {
221 int (*pre_doit)(const struct genl_split_ops *ops,
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,
228 struct genl_info *info);
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);
237 const struct nla_policy *policy;
238 unsigned int maxattr;
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
251 struct genl_dumpit_info {
252 const struct genl_family *family;
253 struct genl_split_ops op;
254 struct nlattr **attrs;
257 static inline const struct genl_dumpit_info *
258 genl_dumpit_info(struct netlink_callback *cb)
263 int genl_register_family(struct genl_family *family);
264 int genl_unregister_family(const struct genl_family *family);
265 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
266 struct genl_info *info, u32 group, gfp_t flags);
268 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
269 const struct genl_family *family, int flags, u8 cmd);
272 * genlmsg_nlhdr - Obtain netlink header from user specified header
273 * @user_hdr: user header as returned from genlmsg_put()
275 * Returns pointer to netlink header.
277 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
279 return (struct nlmsghdr *)((char *)user_hdr -
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
293 static 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)
299 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
300 policy, NL_VALIDATE_LIBERAL, extack);
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
312 static 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)
318 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
319 policy, NL_VALIDATE_STRICT, extack);
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()
327 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
328 * simpler to use with generic netlink.
330 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
333 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
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
344 * Returns pointer to user specific header
346 static inline void *genlmsg_put_reply(struct sk_buff *skb,
347 struct genl_info *info,
348 const struct genl_family *family,
351 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
356 * genlmsg_end - Finalize a generic netlink message
357 * @skb: socket buffer the message is stored in
358 * @hdr: user specific header
360 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
362 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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
370 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
373 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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
385 static 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)
389 if (WARN_ON_ONCE(group >= family->n_mcgrps))
391 group = family->mcgrp_offset + group;
392 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
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
403 static inline int genlmsg_multicast(const struct genl_family *family,
404 struct sk_buff *skb, u32 portid,
405 unsigned int group, gfp_t flags)
407 return genlmsg_multicast_netns(family, &init_net, skb,
408 portid, group, flags);
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
419 * This function must hold the RTNL or rcu_read_lock().
421 int genlmsg_multicast_allns(const struct genl_family *family,
422 struct sk_buff *skb, u32 portid,
423 unsigned int group, gfp_t flags);
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
431 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
433 return nlmsg_unicast(net->genl_sock, skb, portid);
437 * genlmsg_reply - reply to a request
438 * @skb: netlink message to be sent back
439 * @info: receiver information
441 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
443 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
447 * genlmsg_data - head of message payload
448 * @gnlh: genetlink message header
450 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
452 return ((unsigned char *) gnlh + GENL_HDRLEN);
456 * genlmsg_len - length of message payload
457 * @gnlh: genetlink message header
459 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
461 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
463 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
467 * genlmsg_msg_size - length of genetlink message not including padding
468 * @payload: length of message payload
470 static inline int genlmsg_msg_size(int payload)
472 return GENL_HDRLEN + payload;
476 * genlmsg_total_size - length of genetlink message including padding
477 * @payload: length of message payload
479 static inline int genlmsg_total_size(int payload)
481 return NLMSG_ALIGN(genlmsg_msg_size(payload));
485 * genlmsg_new - Allocate a new generic netlink message
486 * @payload: size of the message payload
487 * @flags: the type of memory to allocate.
489 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
491 return nlmsg_new(genlmsg_total_size(payload), flags);
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)
503 * This function returns the number of broadcast listeners that have set the
504 * NETLINK_RECV_NO_ENOBUFS socket option.
506 static inline int genl_set_err(const struct genl_family *family,
507 struct net *net, u32 portid,
510 if (WARN_ON_ONCE(group >= family->n_mcgrps))
512 group = family->mcgrp_offset + group;
513 return netlink_set_err(net->genl_sock, portid, group, code);
516 static inline int genl_has_listeners(const struct genl_family *family,
517 struct net *net, unsigned int group)
519 if (WARN_ON_ONCE(group >= family->n_mcgrps))
521 group = family->mcgrp_offset + group;
522 return netlink_has_listeners(net->genl_sock, group);
524 #endif /* __NET_GENERIC_NETLINK_H */