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 idenfitier
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
43 * @family_list: family list
44 * @mcgrps: multicast groups used by this family (private)
45 * @n_mcgrps: number of multicast groups (private)
46 * @mcgrp_offset: starting number of multicast group IDs in this family
47 * @ops: the operations supported by this family (private)
48 * @n_ops: number of operations supported by this family (private)
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; /* private */
68 const struct genl_multicast_group *mcgrps; /* private */
69 unsigned int n_ops; /* private */
70 unsigned int n_mcgrps; /* private */
71 unsigned int mcgrp_offset; /* private */
72 struct list_head family_list; /* private */
73 struct module *module;
77 * struct genl_info - receiving information
78 * @snd_seq: sending sequence number
79 * @snd_portid: netlink portid of sender
80 * @nlhdr: netlink message header
81 * @genlhdr: generic netlink message header
82 * @userhdr: user specific header
83 * @attrs: netlink attributes
84 * @_net: network namespace
85 * @user_ptr: user pointers
86 * @dst_sk: destination socket
91 struct nlmsghdr * nlhdr;
92 struct genlmsghdr * genlhdr;
94 struct nlattr ** attrs;
102 static inline struct net *genl_info_net(struct genl_info *info)
104 return read_pnet(&info->_net);
107 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
109 write_pnet(&info->_net, net);
113 * struct genl_ops - generic netlink operations
114 * @cmd: command identifier
115 * @internal_flags: flags used by the family
117 * @policy: attribute validation policy
118 * @doit: standard command callback
119 * @dumpit: callback for dumpers
120 * @done: completion callback for dumps
121 * @ops_list: operations list
124 const struct nla_policy *policy;
125 int (*doit)(struct sk_buff *skb,
126 struct genl_info *info);
127 int (*dumpit)(struct sk_buff *skb,
128 struct netlink_callback *cb);
129 int (*done)(struct netlink_callback *cb);
135 int __genl_register_family(struct genl_family *family);
137 static inline int genl_register_family(struct genl_family *family)
139 family->module = THIS_MODULE;
140 return __genl_register_family(family);
144 * genl_register_family_with_ops - register a generic netlink family with ops
145 * @family: generic netlink family
146 * @ops: operations to be registered
147 * @n_ops: number of elements to register
149 * Registers the specified family and operations from the specified table.
150 * Only one family may be registered with the same family name or identifier.
152 * The family id may equal GENL_ID_GENERATE causing an unique id to
153 * be automatically generated and assigned.
155 * Either a doit or dumpit callback must be specified for every registered
156 * operation or the function will fail. Only one operation structure per
157 * command identifier may be registered.
159 * See include/net/genetlink.h for more documenation on the operations
162 * Return 0 on success or a negative error code.
165 _genl_register_family_with_ops_grps(struct genl_family *family,
166 const struct genl_ops *ops, size_t n_ops,
167 const struct genl_multicast_group *mcgrps,
170 family->module = THIS_MODULE;
172 family->n_ops = n_ops;
173 family->mcgrps = mcgrps;
174 family->n_mcgrps = n_mcgrps;
175 return __genl_register_family(family);
178 #define genl_register_family_with_ops(family, ops) \
179 _genl_register_family_with_ops_grps((family), \
180 (ops), ARRAY_SIZE(ops), \
182 #define genl_register_family_with_ops_groups(family, ops, grps) \
183 _genl_register_family_with_ops_grps((family), \
184 (ops), ARRAY_SIZE(ops), \
185 (grps), ARRAY_SIZE(grps))
187 int genl_unregister_family(struct genl_family *family);
188 void genl_notify(struct genl_family *family,
189 struct sk_buff *skb, struct net *net, u32 portid,
190 u32 group, struct nlmsghdr *nlh, gfp_t flags);
192 struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
194 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
195 struct genl_family *family, int flags, u8 cmd);
198 * genlmsg_nlhdr - Obtain netlink header from user specified header
199 * @user_hdr: user header as returned from genlmsg_put()
200 * @family: generic netlink family
202 * Returns pointer to netlink header.
204 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
205 struct genl_family *family)
207 return (struct nlmsghdr *)((char *)user_hdr -
214 * genlmsg_parse - parse attributes of a genetlink message
215 * @nlh: netlink message header
216 * @family: genetlink message family
217 * @tb: destination array with maxtype+1 elements
218 * @maxtype: maximum attribute type to be expected
219 * @policy: validation policy
221 static inline int genlmsg_parse(const struct nlmsghdr *nlh,
222 const struct genl_family *family,
223 struct nlattr *tb[], int maxtype,
224 const struct nla_policy *policy)
226 return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
231 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
232 * @cb: netlink callback structure that stores the sequence number
233 * @user_hdr: user header as returned from genlmsg_put()
234 * @family: generic netlink family
236 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
237 * simpler to use with generic netlink.
239 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
241 struct genl_family *family)
243 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
247 * genlmsg_put_reply - Add generic netlink header to a reply message
248 * @skb: socket buffer holding the message
249 * @info: receiver info
250 * @family: generic netlink family
251 * @flags: netlink message flags
252 * @cmd: generic netlink command
254 * Returns pointer to user specific header
256 static inline void *genlmsg_put_reply(struct sk_buff *skb,
257 struct genl_info *info,
258 struct genl_family *family,
261 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
266 * genlmsg_end - Finalize a generic netlink message
267 * @skb: socket buffer the message is stored in
268 * @hdr: user specific header
270 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
272 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
276 * genlmsg_cancel - Cancel construction of a generic netlink message
277 * @skb: socket buffer the message is stored in
278 * @hdr: generic netlink message header
280 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
283 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
287 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
288 * @family: the generic netlink family
289 * @net: the net namespace
290 * @skb: netlink message as socket buffer
291 * @portid: own netlink portid to avoid sending to yourself
292 * @group: offset of multicast group in groups array
293 * @flags: allocation flags
295 static inline int genlmsg_multicast_netns(struct genl_family *family,
296 struct net *net, struct sk_buff *skb,
297 u32 portid, unsigned int group, gfp_t flags)
299 if (WARN_ON_ONCE(group >= family->n_mcgrps))
301 group = family->mcgrp_offset + group;
302 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
306 * genlmsg_multicast - multicast a netlink message to the default netns
307 * @family: the generic netlink family
308 * @skb: netlink message as socket buffer
309 * @portid: own netlink portid to avoid sending to yourself
310 * @group: offset of multicast group in groups array
311 * @flags: allocation flags
313 static inline int genlmsg_multicast(struct genl_family *family,
314 struct sk_buff *skb, u32 portid,
315 unsigned int group, gfp_t flags)
317 return genlmsg_multicast_netns(family, &init_net, skb,
318 portid, group, flags);
322 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
323 * @family: the generic netlink family
324 * @skb: netlink message as socket buffer
325 * @portid: own netlink portid to avoid sending to yourself
326 * @group: offset of multicast group in groups array
327 * @flags: allocation flags
329 * This function must hold the RTNL or rcu_read_lock().
331 int genlmsg_multicast_allns(struct genl_family *family,
332 struct sk_buff *skb, u32 portid,
333 unsigned int group, gfp_t flags);
336 * genlmsg_unicast - unicast a netlink message
337 * @skb: netlink message as socket buffer
338 * @portid: netlink portid of the destination socket
340 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
342 return nlmsg_unicast(net->genl_sock, skb, portid);
346 * genlmsg_reply - reply to a request
347 * @skb: netlink message to be sent back
348 * @info: receiver information
350 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
352 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
356 * gennlmsg_data - head of message payload
357 * @gnlh: genetlink message header
359 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
361 return ((unsigned char *) gnlh + GENL_HDRLEN);
365 * genlmsg_len - length of message payload
366 * @gnlh: genetlink message header
368 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
370 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
372 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
376 * genlmsg_msg_size - length of genetlink message not including padding
377 * @payload: length of message payload
379 static inline int genlmsg_msg_size(int payload)
381 return GENL_HDRLEN + payload;
385 * genlmsg_total_size - length of genetlink message including padding
386 * @payload: length of message payload
388 static inline int genlmsg_total_size(int payload)
390 return NLMSG_ALIGN(genlmsg_msg_size(payload));
394 * genlmsg_new - Allocate a new generic netlink message
395 * @payload: size of the message payload
396 * @flags: the type of memory to allocate.
398 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
400 return nlmsg_new(genlmsg_total_size(payload), flags);
404 * genl_set_err - report error to genetlink broadcast listeners
405 * @family: the generic netlink family
406 * @net: the network namespace to report the error to
407 * @portid: the PORTID of a process that we want to skip (if any)
408 * @group: the broadcast group that will notice the error
409 * (this is the offset of the multicast group in the groups array)
410 * @code: error code, must be negative (as usual in kernelspace)
412 * This function returns the number of broadcast listeners that have set the
413 * NETLINK_RECV_NO_ENOBUFS socket option.
415 static inline int genl_set_err(struct genl_family *family, struct net *net,
416 u32 portid, u32 group, int code)
418 if (WARN_ON_ONCE(group >= family->n_mcgrps))
420 group = family->mcgrp_offset + group;
421 return netlink_set_err(net->genl_sock, portid, group, code);
424 static inline int genl_has_listeners(struct genl_family *family,
425 struct net *net, unsigned int group)
427 if (WARN_ON_ONCE(group >= family->n_mcgrps))
429 group = family->mcgrp_offset + group;
430 return netlink_has_listeners(net->genl_sock, group);
432 #endif /* __NET_GENERIC_NETLINK_H */