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[deliverable/linux.git] / include / net / genetlink.h
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1#ifndef __NET_GENERIC_NETLINK_H
2#define __NET_GENERIC_NETLINK_H
3
4#include <linux/genetlink.h>
5#include <net/netlink.h>
134e6375 6#include <net/net_namespace.h>
482a8524 7
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8#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
9
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10/**
11 * struct genl_multicast_group - generic netlink multicast group
12 * @name: name of the multicast group, names are per-family
2dbba6f7 13 */
fd2c3ef7 14struct genl_multicast_group {
2dbba6f7 15 char name[GENL_NAMSIZ];
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16};
17
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18struct genl_ops;
19struct genl_info;
20
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21/**
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
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28 * @netnsok: set to true if the family can handle network
29 * namespaces and should be presented in all of them
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30 * @parallel_ops: operations can be called in parallel and aren't
31 * synchronized by the core genetlink code
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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
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36 * @mcast_bind: a socket bound to the given multicast group (which
37 * is given as the offset into the groups array)
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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
41 * sockets.
482a8524 42 * @attrbuf: buffer to store parsed attributes
482a8524 43 * @family_list: family list
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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
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47 * @ops: the operations supported by this family (private)
48 * @n_ops: number of operations supported by this family (private)
482a8524 49 */
fd2c3ef7 50struct genl_family {
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51 unsigned int id;
52 unsigned int hdrsize;
53 char name[GENL_NAMSIZ];
54 unsigned int version;
55 unsigned int maxattr;
134e6375 56 bool netnsok;
def31174 57 bool parallel_ops;
f84f771d 58 int (*pre_doit)(const struct genl_ops *ops,
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59 struct sk_buff *skb,
60 struct genl_info *info);
f84f771d 61 void (*post_doit)(const struct genl_ops *ops,
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62 struct sk_buff *skb,
63 struct genl_info *info);
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64 int (*mcast_bind)(struct net *net, int group);
65 void (*mcast_unbind)(struct net *net, int group);
482a8524 66 struct nlattr ** attrbuf; /* private */
f84f771d 67 const struct genl_ops * ops; /* private */
2a94fe48 68 const struct genl_multicast_group *mcgrps; /* private */
d91824c0 69 unsigned int n_ops; /* private */
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70 unsigned int n_mcgrps; /* private */
71 unsigned int mcgrp_offset; /* private */
482a8524 72 struct list_head family_list; /* private */
33c6b1f6 73 struct module *module;
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74};
75
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76/**
77 * struct genl_info - receiving information
78 * @snd_seq: sending sequence number
15e47304 79 * @snd_portid: netlink portid of sender
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80 * @nlhdr: netlink message header
81 * @genlhdr: generic netlink message header
82 * @userhdr: user specific header
83 * @attrs: netlink attributes
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84 * @_net: network namespace
85 * @user_ptr: user pointers
bb9b18fb 86 * @dst_sk: destination socket
482a8524 87 */
fd2c3ef7 88struct genl_info {
482a8524 89 u32 snd_seq;
15e47304 90 u32 snd_portid;
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91 struct nlmsghdr * nlhdr;
92 struct genlmsghdr * genlhdr;
93 void * userhdr;
94 struct nlattr ** attrs;
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95#ifdef CONFIG_NET_NS
96 struct net * _net;
97#endif
ff4c92d8 98 void * user_ptr[2];
bb9b18fb 99 struct sock * dst_sk;
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100};
101
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102static inline struct net *genl_info_net(struct genl_info *info)
103{
c2d9ba9b 104 return read_pnet(&info->_net);
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105}
106
107static inline void genl_info_net_set(struct genl_info *info, struct net *net)
108{
c2d9ba9b 109 write_pnet(&info->_net, net);
134e6375 110}
134e6375 111
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112/**
113 * struct genl_ops - generic netlink operations
114 * @cmd: command identifier
ff4c92d8 115 * @internal_flags: flags used by the family
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116 * @flags: flags
117 * @policy: attribute validation policy
118 * @doit: standard command callback
119 * @dumpit: callback for dumpers
a4d1366d 120 * @done: completion callback for dumps
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121 * @ops_list: operations list
122 */
fd2c3ef7 123struct genl_ops {
ef7c79ed 124 const struct nla_policy *policy;
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125 int (*doit)(struct sk_buff *skb,
126 struct genl_info *info);
127 int (*dumpit)(struct sk_buff *skb,
128 struct netlink_callback *cb);
a4d1366d 129 int (*done)(struct netlink_callback *cb);
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130 u8 cmd;
131 u8 internal_flags;
132 u8 flags;
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133};
134
ff2b94d2 135int __genl_register_family(struct genl_family *family);
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136
137static inline int genl_register_family(struct genl_family *family)
138{
139 family->module = THIS_MODULE;
140 return __genl_register_family(family);
141}
142
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143/**
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
148 *
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.
151 *
152 * The family id may equal GENL_ID_GENERATE causing an unique id to
153 * be automatically generated and assigned.
154 *
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.
158 *
159 * See include/net/genetlink.h for more documenation on the operations
160 * structure.
161 *
162 * Return 0 on success or a negative error code.
163 */
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164static inline int
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,
168 size_t n_mcgrps)
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169{
170 family->module = THIS_MODULE;
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171 family->ops = ops;
172 family->n_ops = n_ops;
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173 family->mcgrps = mcgrps;
174 family->n_mcgrps = n_mcgrps;
568508aa 175 return __genl_register_family(family);
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176}
177
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178#define genl_register_family_with_ops(family, ops) \
179 _genl_register_family_with_ops_grps((family), \
180 (ops), ARRAY_SIZE(ops), \
181 NULL, 0)
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))
c53ed742 186
ff2b94d2 187int genl_unregister_family(struct genl_family *family);
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188void genl_notify(struct genl_family *family,
189 struct sk_buff *skb, struct net *net, u32 portid,
ff2b94d2 190 u32 group, struct nlmsghdr *nlh, gfp_t flags);
482a8524 191
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192struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
193 gfp_t flags);
15e47304 194void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
ff2b94d2 195 struct genl_family *family, int flags, u8 cmd);
482a8524 196
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197/**
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
201 *
202 * Returns pointer to netlink header.
203 */
204static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
205 struct genl_family *family)
206{
207 return (struct nlmsghdr *)((char *)user_hdr -
208 family->hdrsize -
209 GENL_HDRLEN -
210 NLMSG_HDRLEN);
211}
212
213/**
214 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
215 * @cb: netlink callback structure that stores the sequence number
216 * @user_hdr: user header as returned from genlmsg_put()
217 * @family: generic netlink family
218 *
219 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
220 * simpler to use with generic netlink.
221 */
222static inline void genl_dump_check_consistent(struct netlink_callback *cb,
223 void *user_hdr,
224 struct genl_family *family)
225{
226 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
227}
228
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229/**
230 * genlmsg_put_reply - Add generic netlink header to a reply message
231 * @skb: socket buffer holding the message
232 * @info: receiver info
233 * @family: generic netlink family
234 * @flags: netlink message flags
235 * @cmd: generic netlink command
236 *
237 * Returns pointer to user specific header
238 */
239static inline void *genlmsg_put_reply(struct sk_buff *skb,
240 struct genl_info *info,
241 struct genl_family *family,
242 int flags, u8 cmd)
243{
15e47304 244 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
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245 flags, cmd);
246}
247
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248/**
249 * genlmsg_end - Finalize a generic netlink message
250 * @skb: socket buffer the message is stored in
251 * @hdr: user specific header
252 */
253static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
254{
255 return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
256}
257
258/**
259 * genlmsg_cancel - Cancel construction of a generic netlink message
260 * @skb: socket buffer the message is stored in
261 * @hdr: generic netlink message header
262 */
bc3ed28c 263static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
482a8524 264{
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265 if (hdr)
266 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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267}
268
269/**
134e6375 270 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
68eb5503 271 * @family: the generic netlink family
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272 * @net: the net namespace
273 * @skb: netlink message as socket buffer
15e47304 274 * @portid: own netlink portid to avoid sending to yourself
2a94fe48 275 * @group: offset of multicast group in groups array
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276 * @flags: allocation flags
277 */
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278static inline int genlmsg_multicast_netns(struct genl_family *family,
279 struct net *net, struct sk_buff *skb,
15e47304 280 u32 portid, unsigned int group, gfp_t flags)
134e6375 281{
220815a9 282 if (WARN_ON_ONCE(group >= family->n_mcgrps))
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283 return -EINVAL;
284 group = family->mcgrp_offset + group;
15e47304 285 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
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286}
287
288/**
289 * genlmsg_multicast - multicast a netlink message to the default netns
68eb5503 290 * @family: the generic netlink family
482a8524 291 * @skb: netlink message as socket buffer
15e47304 292 * @portid: own netlink portid to avoid sending to yourself
2a94fe48 293 * @group: offset of multicast group in groups array
d387f6ad 294 * @flags: allocation flags
482a8524 295 */
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296static inline int genlmsg_multicast(struct genl_family *family,
297 struct sk_buff *skb, u32 portid,
d387f6ad 298 unsigned int group, gfp_t flags)
482a8524 299{
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300 return genlmsg_multicast_netns(family, &init_net, skb,
301 portid, group, flags);
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302}
303
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304/**
305 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
68eb5503 306 * @family: the generic netlink family
134e6375 307 * @skb: netlink message as socket buffer
15e47304 308 * @portid: own netlink portid to avoid sending to yourself
2a94fe48 309 * @group: offset of multicast group in groups array
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310 * @flags: allocation flags
311 *
312 * This function must hold the RTNL or rcu_read_lock().
313 */
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314int genlmsg_multicast_allns(struct genl_family *family,
315 struct sk_buff *skb, u32 portid,
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316 unsigned int group, gfp_t flags);
317
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318/**
319 * genlmsg_unicast - unicast a netlink message
320 * @skb: netlink message as socket buffer
15e47304 321 * @portid: netlink portid of the destination socket
482a8524 322 */
15e47304 323static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
482a8524 324{
15e47304 325 return nlmsg_unicast(net->genl_sock, skb, portid);
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326}
327
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328/**
329 * genlmsg_reply - reply to a request
330 * @skb: netlink message to be sent back
331 * @info: receiver information
332 */
333static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
334{
15e47304 335 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
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336}
337
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BS
338/**
339 * gennlmsg_data - head of message payload
70f23fd6 340 * @gnlh: genetlink message header
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BS
341 */
342static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
343{
344 return ((unsigned char *) gnlh + GENL_HDRLEN);
345}
346
347/**
348 * genlmsg_len - length of message payload
349 * @gnlh: genetlink message header
350 */
351static inline int genlmsg_len(const struct genlmsghdr *gnlh)
352{
353 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
354 NLMSG_HDRLEN);
355 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
356}
357
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BS
358/**
359 * genlmsg_msg_size - length of genetlink message not including padding
360 * @payload: length of message payload
361 */
362static inline int genlmsg_msg_size(int payload)
363{
364 return GENL_HDRLEN + payload;
365}
366
367/**
368 * genlmsg_total_size - length of genetlink message including padding
369 * @payload: length of message payload
370 */
371static inline int genlmsg_total_size(int payload)
372{
373 return NLMSG_ALIGN(genlmsg_msg_size(payload));
374}
375
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376/**
377 * genlmsg_new - Allocate a new generic netlink message
378 * @payload: size of the message payload
379 * @flags: the type of memory to allocate.
380 */
381static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
382{
383 return nlmsg_new(genlmsg_total_size(payload), flags);
384}
385
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386/**
387 * genl_set_err - report error to genetlink broadcast listeners
68eb5503 388 * @family: the generic netlink family
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389 * @net: the network namespace to report the error to
390 * @portid: the PORTID of a process that we want to skip (if any)
391 * @group: the broadcast group that will notice the error
2a94fe48 392 * (this is the offset of the multicast group in the groups array)
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393 * @code: error code, must be negative (as usual in kernelspace)
394 *
395 * This function returns the number of broadcast listeners that have set the
396 * NETLINK_RECV_NO_ENOBUFS socket option.
397 */
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398static inline int genl_set_err(struct genl_family *family, struct net *net,
399 u32 portid, u32 group, int code)
62b68e99 400{
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401 if (WARN_ON_ONCE(group >= family->n_mcgrps))
402 return -EINVAL;
403 group = family->mcgrp_offset + group;
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404 return netlink_set_err(net->genl_sock, portid, group, code);
405}
3dabc715 406
0d566379 407static inline int genl_has_listeners(struct genl_family *family,
f8403a2e 408 struct net *net, unsigned int group)
0d566379
ND
409{
410 if (WARN_ON_ONCE(group >= family->n_mcgrps))
411 return -EINVAL;
412 group = family->mcgrp_offset + group;
f8403a2e 413 return netlink_has_listeners(net->genl_sock, group);
0d566379 414}
482a8524 415#endif /* __NET_GENERIC_NETLINK_H */
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