1 #ifndef __NET_GENERIC_NETLINK_H
2 #define __NET_GENERIC_NETLINK_H
4 #include <linux/genetlink.h>
5 #include <net/netlink.h>
6 #include <net/net_namespace.h>
8 #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
11 * struct genl_multicast_group - generic netlink multicast group
12 * @name: name of the multicast group, names are per-family
14 struct genl_multicast_group {
15 char name[GENL_NAMSIZ];
22 * struct genl_family - generic netlink family
23 * @id: protocol family identifier (private)
24 * @hdrsize: length of user specific header in bytes
25 * @name: name of family
26 * @version: protocol version
27 * @maxattr: maximum number of attributes supported
28 * @netnsok: set to true if the family can handle network
29 * namespaces and should be presented in all of them
30 * @parallel_ops: operations can be called in parallel and aren't
31 * synchronized by the core genetlink code
32 * @pre_doit: called before an operation's doit callback, it may
33 * do additional, common, filtering and return an error
34 * @post_doit: called after an operation's doit callback, it may
35 * undo operations done by pre_doit, for example release locks
36 * @mcast_bind: a socket bound to the given multicast group (which
37 * is given as the offset into the groups array)
38 * @mcast_unbind: a socket was unbound from the given multicast group.
39 * Note that unbind() will not be called symmetrically if the
40 * generic netlink family is removed while there are still open
42 * @attrbuf: buffer to store parsed attributes (private)
43 * @mcgrps: multicast groups used by this family
44 * @n_mcgrps: number of multicast groups
45 * @mcgrp_offset: starting number of multicast group IDs in this family
47 * @ops: the operations supported by this family
48 * @n_ops: number of operations supported by this family
53 char name[GENL_NAMSIZ];
58 int (*pre_doit)(const struct genl_ops *ops,
60 struct genl_info *info);
61 void (*post_doit)(const struct genl_ops *ops,
63 struct genl_info *info);
64 int (*mcast_bind)(struct net *net, int group);
65 void (*mcast_unbind)(struct net *net, int group);
66 struct nlattr ** attrbuf; /* private */
67 const struct genl_ops * ops;
68 const struct genl_multicast_group *mcgrps;
70 unsigned int n_mcgrps;
71 unsigned int mcgrp_offset; /* private */
72 struct module *module;
75 struct nlattr **genl_family_attrbuf(const struct genl_family *family);
78 * struct genl_info - receiving information
79 * @snd_seq: sending sequence number
80 * @snd_portid: netlink portid of sender
81 * @nlhdr: netlink message header
82 * @genlhdr: generic netlink message header
83 * @userhdr: user specific header
84 * @attrs: netlink attributes
85 * @_net: network namespace
86 * @user_ptr: user pointers
87 * @extack: extended ACK report struct
92 struct nlmsghdr * nlhdr;
93 struct genlmsghdr * genlhdr;
95 struct nlattr ** attrs;
98 struct netlink_ext_ack *extack;
101 static inline struct net *genl_info_net(struct genl_info *info)
103 return read_pnet(&info->_net);
106 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
108 write_pnet(&info->_net, net);
111 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
113 static inline int genl_err_attr(struct genl_info *info, int err,
116 info->extack->bad_attr = attr;
122 * struct genl_ops - generic netlink operations
123 * @cmd: command identifier
124 * @internal_flags: flags used by the family
126 * @policy: attribute validation policy
127 * @doit: standard command callback
128 * @start: start callback for dumps
129 * @dumpit: callback for dumpers
130 * @done: completion callback for dumps
131 * @ops_list: operations list
134 const struct nla_policy *policy;
135 int (*doit)(struct sk_buff *skb,
136 struct genl_info *info);
137 int (*start)(struct netlink_callback *cb);
138 int (*dumpit)(struct sk_buff *skb,
139 struct netlink_callback *cb);
140 int (*done)(struct netlink_callback *cb);
146 int genl_register_family(struct genl_family *family);
147 int genl_unregister_family(const struct genl_family *family);
148 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
149 struct genl_info *info, u32 group, gfp_t flags);
151 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
152 const struct genl_family *family, int flags, u8 cmd);
155 * genlmsg_nlhdr - Obtain netlink header from user specified header
156 * @user_hdr: user header as returned from genlmsg_put()
157 * @family: generic netlink family
159 * Returns pointer to netlink header.
161 static inline struct nlmsghdr *
162 genlmsg_nlhdr(void *user_hdr, const struct genl_family *family)
164 return (struct nlmsghdr *)((char *)user_hdr -
171 * genlmsg_parse - parse attributes of a genetlink message
172 * @nlh: netlink message header
173 * @family: genetlink message family
174 * @tb: destination array with maxtype+1 elements
175 * @maxtype: maximum attribute type to be expected
176 * @policy: validation policy
177 * @extack: extended ACK report struct
179 static inline int genlmsg_parse(const struct nlmsghdr *nlh,
180 const struct genl_family *family,
181 struct nlattr *tb[], int maxtype,
182 const struct nla_policy *policy,
183 struct netlink_ext_ack *extack)
185 return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
190 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
191 * @cb: netlink callback structure that stores the sequence number
192 * @user_hdr: user header as returned from genlmsg_put()
193 * @family: generic netlink family
195 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
196 * simpler to use with generic netlink.
198 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
200 const struct genl_family *family)
202 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
206 * genlmsg_put_reply - Add generic netlink header to a reply message
207 * @skb: socket buffer holding the message
208 * @info: receiver info
209 * @family: generic netlink family
210 * @flags: netlink message flags
211 * @cmd: generic netlink command
213 * Returns pointer to user specific header
215 static inline void *genlmsg_put_reply(struct sk_buff *skb,
216 struct genl_info *info,
217 const struct genl_family *family,
220 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
225 * genlmsg_end - Finalize a generic netlink message
226 * @skb: socket buffer the message is stored in
227 * @hdr: user specific header
229 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
231 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
235 * genlmsg_cancel - Cancel construction of a generic netlink message
236 * @skb: socket buffer the message is stored in
237 * @hdr: generic netlink message header
239 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
242 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
246 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
247 * @family: the generic netlink family
248 * @net: the net namespace
249 * @skb: netlink message as socket buffer
250 * @portid: own netlink portid to avoid sending to yourself
251 * @group: offset of multicast group in groups array
252 * @flags: allocation flags
254 static inline int genlmsg_multicast_netns(const struct genl_family *family,
255 struct net *net, struct sk_buff *skb,
256 u32 portid, unsigned int group, gfp_t flags)
258 if (WARN_ON_ONCE(group >= family->n_mcgrps))
260 group = family->mcgrp_offset + group;
261 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
265 * genlmsg_multicast - multicast a netlink message to the default netns
266 * @family: the generic netlink family
267 * @skb: netlink message as socket buffer
268 * @portid: own netlink portid to avoid sending to yourself
269 * @group: offset of multicast group in groups array
270 * @flags: allocation flags
272 static inline int genlmsg_multicast(const struct genl_family *family,
273 struct sk_buff *skb, u32 portid,
274 unsigned int group, gfp_t flags)
276 return genlmsg_multicast_netns(family, &init_net, skb,
277 portid, group, flags);
281 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
282 * @family: the generic netlink family
283 * @skb: netlink message as socket buffer
284 * @portid: own netlink portid to avoid sending to yourself
285 * @group: offset of multicast group in groups array
286 * @flags: allocation flags
288 * This function must hold the RTNL or rcu_read_lock().
290 int genlmsg_multicast_allns(const struct genl_family *family,
291 struct sk_buff *skb, u32 portid,
292 unsigned int group, gfp_t flags);
295 * genlmsg_unicast - unicast a netlink message
296 * @skb: netlink message as socket buffer
297 * @portid: netlink portid of the destination socket
299 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
301 return nlmsg_unicast(net->genl_sock, skb, portid);
305 * genlmsg_reply - reply to a request
306 * @skb: netlink message to be sent back
307 * @info: receiver information
309 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
311 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
315 * gennlmsg_data - head of message payload
316 * @gnlh: genetlink message header
318 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
320 return ((unsigned char *) gnlh + GENL_HDRLEN);
324 * genlmsg_len - length of message payload
325 * @gnlh: genetlink message header
327 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
329 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
331 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
335 * genlmsg_msg_size - length of genetlink message not including padding
336 * @payload: length of message payload
338 static inline int genlmsg_msg_size(int payload)
340 return GENL_HDRLEN + payload;
344 * genlmsg_total_size - length of genetlink message including padding
345 * @payload: length of message payload
347 static inline int genlmsg_total_size(int payload)
349 return NLMSG_ALIGN(genlmsg_msg_size(payload));
353 * genlmsg_new - Allocate a new generic netlink message
354 * @payload: size of the message payload
355 * @flags: the type of memory to allocate.
357 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
359 return nlmsg_new(genlmsg_total_size(payload), flags);
363 * genl_set_err - report error to genetlink broadcast listeners
364 * @family: the generic netlink family
365 * @net: the network namespace to report the error to
366 * @portid: the PORTID of a process that we want to skip (if any)
367 * @group: the broadcast group that will notice the error
368 * (this is the offset of the multicast group in the groups array)
369 * @code: error code, must be negative (as usual in kernelspace)
371 * This function returns the number of broadcast listeners that have set the
372 * NETLINK_RECV_NO_ENOBUFS socket option.
374 static inline int genl_set_err(const struct genl_family *family,
375 struct net *net, u32 portid,
378 if (WARN_ON_ONCE(group >= family->n_mcgrps))
380 group = family->mcgrp_offset + group;
381 return netlink_set_err(net->genl_sock, portid, group, code);
384 static inline int genl_has_listeners(const struct genl_family *family,
385 struct net *net, unsigned int group)
387 if (WARN_ON_ONCE(group >= family->n_mcgrps))
389 group = family->mcgrp_offset + group;
390 return netlink_has_listeners(net->genl_sock, group);
392 #endif /* __NET_GENERIC_NETLINK_H */