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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
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2#ifndef __NET_GENERIC_NETLINK_H
3#define __NET_GENERIC_NETLINK_H
4
5#include <linux/genetlink.h>
6#include <net/netlink.h>
134e6375 7#include <net/net_namespace.h>
482a8524 8
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9#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
10
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11/**
12 * struct genl_multicast_group - generic netlink multicast group
13 * @name: name of the multicast group, names are per-family
2dbba6f7 14 */
fd2c3ef7 15struct genl_multicast_group {
2dbba6f7 16 char name[GENL_NAMSIZ];
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JB
17};
18
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19struct genl_ops;
20struct genl_info;
21
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22/**
23 * struct genl_family - generic netlink family
a07ea4d9 24 * @id: protocol family identifier (private)
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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
3b0f31f2 29 * @policy: netlink policy
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30 * @netnsok: set to true if the family can handle network
31 * namespaces and should be presented in all of them
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32 * @parallel_ops: operations can be called in parallel and aren't
33 * synchronized by the core genetlink code
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34 * @pre_doit: called before an operation's doit callback, it may
35 * do additional, common, filtering and return an error
36 * @post_doit: called after an operation's doit callback, it may
37 * undo operations done by pre_doit, for example release locks
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38 * @mcast_bind: a socket bound to the given multicast group (which
39 * is given as the offset into the groups array)
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40 * @mcast_unbind: a socket was unbound from the given multicast group.
41 * Note that unbind() will not be called symmetrically if the
42 * generic netlink family is removed while there are still open
43 * sockets.
489111e5 44 * @attrbuf: buffer to store parsed attributes (private)
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45 * @mcgrps: multicast groups used by this family
46 * @n_mcgrps: number of multicast groups
2a94fe48 47 * @mcgrp_offset: starting number of multicast group IDs in this family
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48 * (private)
49 * @ops: the operations supported by this family
50 * @n_ops: number of operations supported by this family
482a8524 51 */
fd2c3ef7 52struct genl_family {
98e4321b 53 int id; /* private */
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54 unsigned int hdrsize;
55 char name[GENL_NAMSIZ];
56 unsigned int version;
57 unsigned int maxattr;
134e6375 58 bool netnsok;
def31174 59 bool parallel_ops;
3b0f31f2 60 const struct nla_policy *policy;
f84f771d 61 int (*pre_doit)(const struct genl_ops *ops,
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62 struct sk_buff *skb,
63 struct genl_info *info);
f84f771d 64 void (*post_doit)(const struct genl_ops *ops,
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65 struct sk_buff *skb,
66 struct genl_info *info);
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67 int (*mcast_bind)(struct net *net, int group);
68 void (*mcast_unbind)(struct net *net, int group);
482a8524 69 struct nlattr ** attrbuf; /* private */
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70 const struct genl_ops * ops;
71 const struct genl_multicast_group *mcgrps;
72 unsigned int n_ops;
73 unsigned int n_mcgrps;
2a94fe48 74 unsigned int mcgrp_offset; /* private */
33c6b1f6 75 struct module *module;
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76};
77
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78/**
79 * struct genl_info - receiving information
80 * @snd_seq: sending sequence number
15e47304 81 * @snd_portid: netlink portid of sender
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82 * @nlhdr: netlink message header
83 * @genlhdr: generic netlink message header
84 * @userhdr: user specific header
85 * @attrs: netlink attributes
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86 * @_net: network namespace
87 * @user_ptr: user pointers
7ab606d1 88 * @extack: extended ACK report struct
482a8524 89 */
fd2c3ef7 90struct genl_info {
482a8524 91 u32 snd_seq;
15e47304 92 u32 snd_portid;
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93 struct nlmsghdr * nlhdr;
94 struct genlmsghdr * genlhdr;
95 void * userhdr;
96 struct nlattr ** attrs;
0c5c9fb5 97 possible_net_t _net;
ff4c92d8 98 void * user_ptr[2];
7ab606d1 99 struct netlink_ext_ack *extack;
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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#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
113
114static inline int genl_err_attr(struct genl_info *info, int err,
6fce10f7 115 const struct nlattr *attr)
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116{
117 info->extack->bad_attr = attr;
118
119 return err;
120}
121
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122enum genl_validate_flags {
123 GENL_DONT_VALIDATE_STRICT = BIT(0),
124 GENL_DONT_VALIDATE_DUMP = BIT(1),
125 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
126};
127
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128/**
129 * struct genl_info - info that is available during dumpit op call
bf813b0a 130 * @family: generic netlink family - for internal genl code usage
1927f41a 131 * @ops: generic netlink ops - for internal genl code usage
bf813b0a 132 * @attrs: netlink attributes
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133 */
134struct genl_dumpit_info {
bf813b0a 135 const struct genl_family *family;
1927f41a 136 const struct genl_ops *ops;
bf813b0a 137 struct nlattr **attrs;
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138};
139
140static inline const struct genl_dumpit_info *
141genl_dumpit_info(struct netlink_callback *cb)
142{
143 return cb->data;
144}
145
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146/**
147 * struct genl_ops - generic netlink operations
148 * @cmd: command identifier
ff4c92d8 149 * @internal_flags: flags used by the family
482a8524 150 * @flags: flags
482a8524 151 * @doit: standard command callback
fc9e50f5 152 * @start: start callback for dumps
482a8524 153 * @dumpit: callback for dumpers
a4d1366d 154 * @done: completion callback for dumps
482a8524 155 */
fd2c3ef7 156struct genl_ops {
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157 int (*doit)(struct sk_buff *skb,
158 struct genl_info *info);
fc9e50f5 159 int (*start)(struct netlink_callback *cb);
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160 int (*dumpit)(struct sk_buff *skb,
161 struct netlink_callback *cb);
a4d1366d 162 int (*done)(struct netlink_callback *cb);
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163 u8 cmd;
164 u8 internal_flags;
165 u8 flags;
ef6243ac 166 u8 validate;
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167};
168
489111e5 169int genl_register_family(struct genl_family *family);
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170int genl_unregister_family(const struct genl_family *family);
171void genl_notify(const struct genl_family *family, struct sk_buff *skb,
92c14d9b 172 struct genl_info *info, u32 group, gfp_t flags);
482a8524 173
15e47304 174void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
2ae0f17d 175 const struct genl_family *family, int flags, u8 cmd);
482a8524 176
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177/**
178 * genlmsg_nlhdr - Obtain netlink header from user specified header
179 * @user_hdr: user header as returned from genlmsg_put()
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180 *
181 * Returns pointer to netlink header.
182 */
0a833c29 183static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
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184{
185 return (struct nlmsghdr *)((char *)user_hdr -
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186 GENL_HDRLEN -
187 NLMSG_HDRLEN);
188}
189
7b1883ce 190/**
8cb08174 191 * genlmsg_parse_deprecated - parse attributes of a genetlink message
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192 * @nlh: netlink message header
193 * @family: genetlink message family
194 * @tb: destination array with maxtype+1 elements
195 * @maxtype: maximum attribute type to be expected
196 * @policy: validation policy
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197 * @extack: extended ACK report struct
198 */
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199static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
200 const struct genl_family *family,
201 struct nlattr *tb[], int maxtype,
202 const struct nla_policy *policy,
203 struct netlink_ext_ack *extack)
7b1883ce 204{
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205 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
206 policy, NL_VALIDATE_LIBERAL, extack);
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207}
208
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209/**
210 * genlmsg_parse - parse attributes of a genetlink message
211 * @nlh: netlink message header
212 * @family: genetlink message family
213 * @tb: destination array with maxtype+1 elements
214 * @maxtype: maximum attribute type to be expected
215 * @policy: validation policy
216 * @extack: extended ACK report struct
217 */
218static inline int genlmsg_parse(const struct nlmsghdr *nlh,
219 const struct genl_family *family,
220 struct nlattr *tb[], int maxtype,
221 const struct nla_policy *policy,
222 struct netlink_ext_ack *extack)
223{
224 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
225 policy, NL_VALIDATE_STRICT, extack);
226}
227
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228/**
229 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
230 * @cb: netlink callback structure that stores the sequence number
231 * @user_hdr: user header as returned from genlmsg_put()
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232 *
233 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
234 * simpler to use with generic netlink.
235 */
236static inline void genl_dump_check_consistent(struct netlink_callback *cb,
0a833c29 237 void *user_hdr)
670dc283 238{
0a833c29 239 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
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240}
241
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242/**
243 * genlmsg_put_reply - Add generic netlink header to a reply message
244 * @skb: socket buffer holding the message
245 * @info: receiver info
246 * @family: generic netlink family
247 * @flags: netlink message flags
248 * @cmd: generic netlink command
249 *
250 * Returns pointer to user specific header
251 */
252static inline void *genlmsg_put_reply(struct sk_buff *skb,
253 struct genl_info *info,
2ae0f17d 254 const struct genl_family *family,
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255 int flags, u8 cmd)
256{
15e47304 257 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
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258 flags, cmd);
259}
260
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261/**
262 * genlmsg_end - Finalize a generic netlink message
263 * @skb: socket buffer the message is stored in
264 * @hdr: user specific header
265 */
053c095a 266static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
482a8524 267{
053c095a 268 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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269}
270
271/**
272 * genlmsg_cancel - Cancel construction of a generic netlink message
273 * @skb: socket buffer the message is stored in
274 * @hdr: generic netlink message header
275 */
bc3ed28c 276static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
482a8524 277{
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278 if (hdr)
279 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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280}
281
282/**
134e6375 283 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
68eb5503 284 * @family: the generic netlink family
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285 * @net: the net namespace
286 * @skb: netlink message as socket buffer
15e47304 287 * @portid: own netlink portid to avoid sending to yourself
2a94fe48 288 * @group: offset of multicast group in groups array
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289 * @flags: allocation flags
290 */
2ae0f17d 291static inline int genlmsg_multicast_netns(const struct genl_family *family,
68eb5503 292 struct net *net, struct sk_buff *skb,
15e47304 293 u32 portid, unsigned int group, gfp_t flags)
134e6375 294{
220815a9 295 if (WARN_ON_ONCE(group >= family->n_mcgrps))
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296 return -EINVAL;
297 group = family->mcgrp_offset + group;
15e47304 298 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
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299}
300
301/**
302 * genlmsg_multicast - multicast a netlink message to the default netns
68eb5503 303 * @family: the generic netlink family
482a8524 304 * @skb: netlink message as socket buffer
15e47304 305 * @portid: own netlink portid to avoid sending to yourself
2a94fe48 306 * @group: offset of multicast group in groups array
d387f6ad 307 * @flags: allocation flags
482a8524 308 */
2ae0f17d 309static inline int genlmsg_multicast(const struct genl_family *family,
68eb5503 310 struct sk_buff *skb, u32 portid,
d387f6ad 311 unsigned int group, gfp_t flags)
482a8524 312{
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JB
313 return genlmsg_multicast_netns(family, &init_net, skb,
314 portid, group, flags);
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315}
316
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317/**
318 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
68eb5503 319 * @family: the generic netlink family
134e6375 320 * @skb: netlink message as socket buffer
15e47304 321 * @portid: own netlink portid to avoid sending to yourself
2a94fe48 322 * @group: offset of multicast group in groups array
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323 * @flags: allocation flags
324 *
325 * This function must hold the RTNL or rcu_read_lock().
326 */
2ae0f17d 327int genlmsg_multicast_allns(const struct genl_family *family,
68eb5503 328 struct sk_buff *skb, u32 portid,
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329 unsigned int group, gfp_t flags);
330
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TG
331/**
332 * genlmsg_unicast - unicast a netlink message
333 * @skb: netlink message as socket buffer
15e47304 334 * @portid: netlink portid of the destination socket
482a8524 335 */
15e47304 336static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
482a8524 337{
15e47304 338 return nlmsg_unicast(net->genl_sock, skb, portid);
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TG
339}
340
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TG
341/**
342 * genlmsg_reply - reply to a request
343 * @skb: netlink message to be sent back
344 * @info: receiver information
345 */
346static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
347{
15e47304 348 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
81878d27
TG
349}
350
fb0ba6bd
BS
351/**
352 * gennlmsg_data - head of message payload
70f23fd6 353 * @gnlh: genetlink message header
fb0ba6bd
BS
354 */
355static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
356{
357 return ((unsigned char *) gnlh + GENL_HDRLEN);
358}
359
360/**
361 * genlmsg_len - length of message payload
362 * @gnlh: genetlink message header
363 */
364static inline int genlmsg_len(const struct genlmsghdr *gnlh)
365{
366 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
367 NLMSG_HDRLEN);
368 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
369}
370
17db952c
BS
371/**
372 * genlmsg_msg_size - length of genetlink message not including padding
373 * @payload: length of message payload
374 */
375static inline int genlmsg_msg_size(int payload)
376{
377 return GENL_HDRLEN + payload;
378}
379
380/**
381 * genlmsg_total_size - length of genetlink message including padding
382 * @payload: length of message payload
383 */
384static inline int genlmsg_total_size(int payload)
385{
386 return NLMSG_ALIGN(genlmsg_msg_size(payload));
387}
388
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TG
389/**
390 * genlmsg_new - Allocate a new generic netlink message
391 * @payload: size of the message payload
392 * @flags: the type of memory to allocate.
393 */
394static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
395{
396 return nlmsg_new(genlmsg_total_size(payload), flags);
397}
398
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JB
399/**
400 * genl_set_err - report error to genetlink broadcast listeners
68eb5503 401 * @family: the generic netlink family
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402 * @net: the network namespace to report the error to
403 * @portid: the PORTID of a process that we want to skip (if any)
404 * @group: the broadcast group that will notice the error
2a94fe48 405 * (this is the offset of the multicast group in the groups array)
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JB
406 * @code: error code, must be negative (as usual in kernelspace)
407 *
408 * This function returns the number of broadcast listeners that have set the
409 * NETLINK_RECV_NO_ENOBUFS socket option.
410 */
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411static inline int genl_set_err(const struct genl_family *family,
412 struct net *net, u32 portid,
413 u32 group, int code)
62b68e99 414{
91398a09
JB
415 if (WARN_ON_ONCE(group >= family->n_mcgrps))
416 return -EINVAL;
417 group = family->mcgrp_offset + group;
62b68e99
JB
418 return netlink_set_err(net->genl_sock, portid, group, code);
419}
3dabc715 420
2ae0f17d 421static inline int genl_has_listeners(const struct genl_family *family,
f8403a2e 422 struct net *net, unsigned int group)
0d566379
ND
423{
424 if (WARN_ON_ONCE(group >= family->n_mcgrps))
425 return -EINVAL;
426 group = family->mcgrp_offset + group;
f8403a2e 427 return netlink_has_listeners(net->genl_sock, group);
0d566379 428}
482a8524 429#endif /* __NET_GENERIC_NETLINK_H */