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 * @netnsok: set to true if the family can handle network
30 * namespaces and should be presented in all of them
31 * @parallel_ops: operations can be called in parallel and aren't
32 * synchronized by the core genetlink code
33 * @pre_doit: called before an operation's doit callback, it may
34 * do additional, common, filtering and return an error
35 * @post_doit: called after an operation's doit callback, it may
36 * undo operations done by pre_doit, for example release locks
37 * @attrbuf: buffer to store parsed attributes (private)
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 int (*pre_doit)(const struct genl_ops *ops,
55 struct genl_info *info);
56 void (*post_doit)(const struct genl_ops *ops,
58 struct genl_info *info);
59 struct nlattr ** attrbuf; /* private */
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;
68 struct nlattr **genl_family_attrbuf(const struct genl_family *family);
71 * struct genl_info - receiving information
72 * @snd_seq: sending sequence number
73 * @snd_portid: netlink portid of sender
74 * @nlhdr: netlink message header
75 * @genlhdr: generic netlink message header
76 * @userhdr: user specific header
77 * @attrs: netlink attributes
78 * @_net: network namespace
79 * @user_ptr: user pointers
80 * @extack: extended ACK report struct
85 struct nlmsghdr * nlhdr;
86 struct genlmsghdr * genlhdr;
88 struct nlattr ** attrs;
91 struct netlink_ext_ack *extack;
94 static inline struct net *genl_info_net(struct genl_info *info)
96 return read_pnet(&info->_net);
99 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
101 write_pnet(&info->_net, net);
104 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
106 static inline int genl_err_attr(struct genl_info *info, int err,
109 info->extack->bad_attr = attr;
115 * struct genl_ops - generic netlink operations
116 * @cmd: command identifier
117 * @internal_flags: flags used by the family
119 * @policy: attribute validation policy
120 * @doit: standard command callback
121 * @start: start callback for dumps
122 * @dumpit: callback for dumpers
123 * @done: completion callback for dumps
126 const struct nla_policy *policy;
127 int (*doit)(struct sk_buff *skb,
128 struct genl_info *info);
129 int (*start)(struct netlink_callback *cb);
130 int (*dumpit)(struct sk_buff *skb,
131 struct netlink_callback *cb);
132 int (*done)(struct netlink_callback *cb);
138 int genl_register_family(struct genl_family *family);
139 int genl_unregister_family(const struct genl_family *family);
140 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
141 struct genl_info *info, u32 group, gfp_t flags);
143 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
144 const struct genl_family *family, int flags, u8 cmd);
147 * genlmsg_nlhdr - Obtain netlink header from user specified header
148 * @user_hdr: user header as returned from genlmsg_put()
150 * Returns pointer to netlink header.
152 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
154 return (struct nlmsghdr *)((char *)user_hdr -
160 * genlmsg_parse - parse attributes of a genetlink message
161 * @nlh: netlink message header
162 * @family: genetlink message family
163 * @tb: destination array with maxtype+1 elements
164 * @maxtype: maximum attribute type to be expected
165 * @policy: validation policy
166 * @extack: extended ACK report struct
168 static inline int genlmsg_parse(const struct nlmsghdr *nlh,
169 const struct genl_family *family,
170 struct nlattr *tb[], int maxtype,
171 const struct nla_policy *policy,
172 struct netlink_ext_ack *extack)
174 return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
179 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
180 * @cb: netlink callback structure that stores the sequence number
181 * @user_hdr: user header as returned from genlmsg_put()
183 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
184 * simpler to use with generic netlink.
186 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
189 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
193 * genlmsg_put_reply - Add generic netlink header to a reply message
194 * @skb: socket buffer holding the message
195 * @info: receiver info
196 * @family: generic netlink family
197 * @flags: netlink message flags
198 * @cmd: generic netlink command
200 * Returns pointer to user specific header
202 static inline void *genlmsg_put_reply(struct sk_buff *skb,
203 struct genl_info *info,
204 const struct genl_family *family,
207 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
212 * genlmsg_end - Finalize a generic netlink message
213 * @skb: socket buffer the message is stored in
214 * @hdr: user specific header
216 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
218 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
222 * genlmsg_cancel - Cancel construction of a generic netlink message
223 * @skb: socket buffer the message is stored in
224 * @hdr: generic netlink message header
226 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
229 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
233 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
234 * @family: the generic netlink family
235 * @net: the net namespace
236 * @skb: netlink message as socket buffer
237 * @portid: own netlink portid to avoid sending to yourself
238 * @group: offset of multicast group in groups array
239 * @flags: allocation flags
241 static inline int genlmsg_multicast_netns(const struct genl_family *family,
242 struct net *net, struct sk_buff *skb,
243 u32 portid, unsigned int group, gfp_t flags)
245 if (WARN_ON_ONCE(group >= family->n_mcgrps))
247 group = family->mcgrp_offset + group;
248 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
252 * genlmsg_multicast - multicast a netlink message to the default netns
253 * @family: the generic netlink family
254 * @skb: netlink message as socket buffer
255 * @portid: own netlink portid to avoid sending to yourself
256 * @group: offset of multicast group in groups array
257 * @flags: allocation flags
259 static inline int genlmsg_multicast(const struct genl_family *family,
260 struct sk_buff *skb, u32 portid,
261 unsigned int group, gfp_t flags)
263 return genlmsg_multicast_netns(family, &init_net, skb,
264 portid, group, flags);
268 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
269 * @family: the generic netlink family
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 * This function must hold the RTNL or rcu_read_lock().
277 int genlmsg_multicast_allns(const struct genl_family *family,
278 struct sk_buff *skb, u32 portid,
279 unsigned int group, gfp_t flags);
282 * genlmsg_unicast - unicast a netlink message
283 * @skb: netlink message as socket buffer
284 * @portid: netlink portid of the destination socket
286 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
288 return nlmsg_unicast(net->genl_sock, skb, portid);
292 * genlmsg_reply - reply to a request
293 * @skb: netlink message to be sent back
294 * @info: receiver information
296 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
298 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
302 * gennlmsg_data - head of message payload
303 * @gnlh: genetlink message header
305 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
307 return ((unsigned char *) gnlh + GENL_HDRLEN);
311 * genlmsg_len - length of message payload
312 * @gnlh: genetlink message header
314 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
316 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
318 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
322 * genlmsg_msg_size - length of genetlink message not including padding
323 * @payload: length of message payload
325 static inline int genlmsg_msg_size(int payload)
327 return GENL_HDRLEN + payload;
331 * genlmsg_total_size - length of genetlink message including padding
332 * @payload: length of message payload
334 static inline int genlmsg_total_size(int payload)
336 return NLMSG_ALIGN(genlmsg_msg_size(payload));
340 * genlmsg_new - Allocate a new generic netlink message
341 * @payload: size of the message payload
342 * @flags: the type of memory to allocate.
344 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
346 return nlmsg_new(genlmsg_total_size(payload), flags);
350 * genl_set_err - report error to genetlink broadcast listeners
351 * @family: the generic netlink family
352 * @net: the network namespace to report the error to
353 * @portid: the PORTID of a process that we want to skip (if any)
354 * @group: the broadcast group that will notice the error
355 * (this is the offset of the multicast group in the groups array)
356 * @code: error code, must be negative (as usual in kernelspace)
358 * This function returns the number of broadcast listeners that have set the
359 * NETLINK_RECV_NO_ENOBUFS socket option.
361 static inline int genl_set_err(const struct genl_family *family,
362 struct net *net, u32 portid,
365 if (WARN_ON_ONCE(group >= family->n_mcgrps))
367 group = family->mcgrp_offset + group;
368 return netlink_set_err(net->genl_sock, portid, group, code);
371 static inline int genl_has_listeners(const struct genl_family *family,
372 struct net *net, unsigned int group)
374 if (WARN_ON_ONCE(group >= family->n_mcgrps))
376 group = family->mcgrp_offset + group;
377 return netlink_has_listeners(net->genl_sock, group);
379 #endif /* __NET_GENERIC_NETLINK_H */