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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __NET_GENERIC_NETLINK_H
3#define __NET_GENERIC_NETLINK_H
4
5#include <linux/net.h>
6#include <net/netlink.h>
7#include <net/net_namespace.h>
8#include <uapi/linux/genetlink.h>
9
10#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
11
12/* Non-parallel generic netlink requests are serialized by a global lock. */
13void genl_lock(void);
14void genl_unlock(void);
15
16#define MODULE_ALIAS_GENL_FAMILY(family) \
17 MODULE_ALIAS_NET_PF_PROTO_NAME(PF_NETLINK, NETLINK_GENERIC, "-family-" family)
18
19/* Binding to multicast group requires %CAP_NET_ADMIN */
20#define GENL_MCAST_CAP_NET_ADMIN BIT(0)
21/* Binding to multicast group requires %CAP_SYS_ADMIN */
22#define GENL_MCAST_CAP_SYS_ADMIN BIT(1)
23
24/**
25 * struct genl_multicast_group - generic netlink multicast group
26 * @name: name of the multicast group, names are per-family
27 * @flags: GENL_MCAST_* flags
28 */
29struct genl_multicast_group {
30 char name[GENL_NAMSIZ];
31 u8 flags;
32};
33
34struct genl_split_ops;
35struct genl_info;
36
37/**
38 * struct genl_family - generic netlink family
39 * @hdrsize: length of user specific header in bytes
40 * @name: name of family
41 * @version: protocol version
42 * @maxattr: maximum number of attributes supported
43 * @policy: netlink policy
44 * @netnsok: set to true if the family can handle network
45 * namespaces and should be presented in all of them
46 * @parallel_ops: operations can be called in parallel and aren't
47 * synchronized by the core genetlink code
48 * @pre_doit: called before an operation's doit callback, it may
49 * do additional, common, filtering and return an error
50 * @post_doit: called after an operation's doit callback, it may
51 * undo operations done by pre_doit, for example release locks
52 * @bind: called when family multicast group is added to a netlink socket
53 * @unbind: called when family multicast group is removed from a netlink socket
54 * @module: pointer to the owning module (set to THIS_MODULE)
55 * @mcgrps: multicast groups used by this family
56 * @n_mcgrps: number of multicast groups
57 * @resv_start_op: first operation for which reserved fields of the header
58 * can be validated and policies are required (see below);
59 * new families should leave this field at zero
60 * @ops: the operations supported by this family
61 * @n_ops: number of operations supported by this family
62 * @small_ops: the small-struct operations supported by this family
63 * @n_small_ops: number of small-struct operations supported by this family
64 * @split_ops: the split do/dump form of operation definition
65 * @n_split_ops: number of entries in @split_ops, not that with split do/dump
66 * ops the number of entries is not the same as number of commands
67 * @sock_priv_size: the size of per-socket private memory
68 * @sock_priv_init: the per-socket private memory initializer
69 * @sock_priv_destroy: the per-socket private memory destructor
70 *
71 * Attribute policies (the combination of @policy and @maxattr fields)
72 * can be attached at the family level or at the operation level.
73 * If both are present the per-operation policy takes precedence.
74 * For operations before @resv_start_op lack of policy means that the core
75 * will perform no attribute parsing or validation. For newer operations
76 * if policy is not provided core will reject all TLV attributes.
77 */
78struct genl_family {
79 unsigned int hdrsize;
80 char name[GENL_NAMSIZ];
81 unsigned int version;
82 unsigned int maxattr;
83 u8 netnsok:1;
84 u8 parallel_ops:1;
85 u8 n_ops;
86 u8 n_small_ops;
87 u8 n_split_ops;
88 u8 n_mcgrps;
89 u8 resv_start_op;
90 const struct nla_policy *policy;
91 int (*pre_doit)(const struct genl_split_ops *ops,
92 struct sk_buff *skb,
93 struct genl_info *info);
94 void (*post_doit)(const struct genl_split_ops *ops,
95 struct sk_buff *skb,
96 struct genl_info *info);
97 int (*bind)(int mcgrp);
98 void (*unbind)(int mcgrp);
99 const struct genl_ops * ops;
100 const struct genl_small_ops *small_ops;
101 const struct genl_split_ops *split_ops;
102 const struct genl_multicast_group *mcgrps;
103 struct module *module;
104
105 size_t sock_priv_size;
106 void (*sock_priv_init)(void *priv);
107 void (*sock_priv_destroy)(void *priv);
108
109/* private: internal use only */
110 /* protocol family identifier */
111 int id;
112 /* starting number of multicast group IDs in this family */
113 unsigned int mcgrp_offset;
114 /* list of per-socket privs */
115 struct xarray *sock_privs;
116};
117
118/**
119 * struct genl_info - receiving information
120 * @snd_seq: sending sequence number
121 * @snd_portid: netlink portid of sender
122 * @family: generic netlink family
123 * @nlhdr: netlink message header
124 * @genlhdr: generic netlink message header
125 * @attrs: netlink attributes
126 * @_net: network namespace
127 * @ctx: storage space for the use by the family
128 * @user_ptr: user pointers (deprecated, use ctx instead)
129 * @extack: extended ACK report struct
130 */
131struct genl_info {
132 u32 snd_seq;
133 u32 snd_portid;
134 const struct genl_family *family;
135 const struct nlmsghdr * nlhdr;
136 struct genlmsghdr * genlhdr;
137 struct nlattr ** attrs;
138 possible_net_t _net;
139 union {
140 u8 ctx[NETLINK_CTX_SIZE];
141 void * user_ptr[2];
142 };
143 struct netlink_ext_ack *extack;
144};
145
146static inline struct net *genl_info_net(const struct genl_info *info)
147{
148 return read_pnet(&info->_net);
149}
150
151static inline void genl_info_net_set(struct genl_info *info, struct net *net)
152{
153 write_pnet(&info->_net, net);
154}
155
156static inline void *genl_info_userhdr(const struct genl_info *info)
157{
158 return (u8 *)info->genlhdr + GENL_HDRLEN;
159}
160
161#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
162
163#define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
164 NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)
165
166/* Report that a root attribute is missing */
167#define GENL_REQ_ATTR_CHECK(info, attr) ({ \
168 const struct genl_info *__info = (info); \
169 \
170 NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
171})
172
173enum genl_validate_flags {
174 GENL_DONT_VALIDATE_STRICT = BIT(0),
175 GENL_DONT_VALIDATE_DUMP = BIT(1),
176 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
177};
178
179/**
180 * struct genl_small_ops - generic netlink operations (small version)
181 * @cmd: command identifier
182 * @internal_flags: flags used by the family
183 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
184 * @validate: validation flags from enum genl_validate_flags
185 * @doit: standard command callback
186 * @dumpit: callback for dumpers
187 *
188 * This is a cut-down version of struct genl_ops for users who don't need
189 * most of the ancillary infra and want to save space.
190 */
191struct genl_small_ops {
192 int (*doit)(struct sk_buff *skb, struct genl_info *info);
193 int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
194 u8 cmd;
195 u8 internal_flags;
196 u8 flags;
197 u8 validate;
198};
199
200/**
201 * struct genl_ops - generic netlink operations
202 * @cmd: command identifier
203 * @internal_flags: flags used by the family
204 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
205 * @maxattr: maximum number of attributes supported
206 * @policy: netlink policy (takes precedence over family policy)
207 * @validate: validation flags from enum genl_validate_flags
208 * @doit: standard command callback
209 * @start: start callback for dumps
210 * @dumpit: callback for dumpers
211 * @done: completion callback for dumps
212 */
213struct genl_ops {
214 int (*doit)(struct sk_buff *skb,
215 struct genl_info *info);
216 int (*start)(struct netlink_callback *cb);
217 int (*dumpit)(struct sk_buff *skb,
218 struct netlink_callback *cb);
219 int (*done)(struct netlink_callback *cb);
220 const struct nla_policy *policy;
221 unsigned int maxattr;
222 u8 cmd;
223 u8 internal_flags;
224 u8 flags;
225 u8 validate;
226};
227
228/**
229 * struct genl_split_ops - generic netlink operations (do/dump split version)
230 * @cmd: command identifier
231 * @internal_flags: flags used by the family
232 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
233 * @validate: validation flags from enum genl_validate_flags
234 * @policy: netlink policy (takes precedence over family policy)
235 * @maxattr: maximum number of attributes supported
236 *
237 * Do callbacks:
238 * @pre_doit: called before an operation's @doit callback, it may
239 * do additional, common, filtering and return an error
240 * @doit: standard command callback
241 * @post_doit: called after an operation's @doit callback, it may
242 * undo operations done by pre_doit, for example release locks
243 *
244 * Dump callbacks:
245 * @start: start callback for dumps
246 * @dumpit: callback for dumpers
247 * @done: completion callback for dumps
248 *
249 * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
250 * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
251 * Exactly one of those flags must be set.
252 */
253struct genl_split_ops {
254 union {
255 struct {
256 int (*pre_doit)(const struct genl_split_ops *ops,
257 struct sk_buff *skb,
258 struct genl_info *info);
259 int (*doit)(struct sk_buff *skb,
260 struct genl_info *info);
261 void (*post_doit)(const struct genl_split_ops *ops,
262 struct sk_buff *skb,
263 struct genl_info *info);
264 };
265 struct {
266 int (*start)(struct netlink_callback *cb);
267 int (*dumpit)(struct sk_buff *skb,
268 struct netlink_callback *cb);
269 int (*done)(struct netlink_callback *cb);
270 };
271 };
272 const struct nla_policy *policy;
273 unsigned int maxattr;
274 u8 cmd;
275 u8 internal_flags;
276 u8 flags;
277 u8 validate;
278};
279
280/**
281 * struct genl_dumpit_info - info that is available during dumpit op call
282 * @op: generic netlink ops - for internal genl code usage
283 * @attrs: netlink attributes
284 * @info: struct genl_info describing the request
285 */
286struct genl_dumpit_info {
287 struct genl_split_ops op;
288 struct genl_info info;
289};
290
291static inline const struct genl_dumpit_info *
292genl_dumpit_info(struct netlink_callback *cb)
293{
294 return cb->data;
295}
296
297static inline const struct genl_info *
298genl_info_dump(struct netlink_callback *cb)
299{
300 return &genl_dumpit_info(cb)->info;
301}
302
303/**
304 * genl_info_init_ntf() - initialize genl_info for notifications
305 * @info: genl_info struct to set up
306 * @family: pointer to the genetlink family
307 * @cmd: command to be used in the notification
308 *
309 * Initialize a locally declared struct genl_info to pass to various APIs.
310 * Intended to be used when creating notifications.
311 */
312static inline void
313genl_info_init_ntf(struct genl_info *info, const struct genl_family *family,
314 u8 cmd)
315{
316 struct genlmsghdr *hdr = (void *) &info->user_ptr[0];
317
318 memset(info, 0, sizeof(*info));
319 info->family = family;
320 info->genlhdr = hdr;
321 hdr->cmd = cmd;
322}
323
324static inline bool genl_info_is_ntf(const struct genl_info *info)
325{
326 return !info->nlhdr;
327}
328
329void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk);
330void *genl_sk_priv_get(struct genl_family *family, struct sock *sk);
331int genl_register_family(struct genl_family *family);
332int genl_unregister_family(const struct genl_family *family);
333void genl_notify(const struct genl_family *family, struct sk_buff *skb,
334 struct genl_info *info, u32 group, gfp_t flags);
335
336void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
337 const struct genl_family *family, int flags, u8 cmd);
338
339static inline void *
340__genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags)
341{
342 return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family,
343 flags, info->genlhdr->cmd);
344}
345
346/**
347 * genlmsg_iput - start genetlink message based on genl_info
348 * @skb: skb in which message header will be placed
349 * @info: genl_info as provided to do/dump handlers
350 *
351 * Convenience wrapper which starts a genetlink message based on
352 * information in user request. @info should be either the struct passed
353 * by genetlink core to do/dump handlers (when constructing replies to
354 * such requests) or a struct initialized by genl_info_init_ntf()
355 * when constructing notifications.
356 *
357 * Returns pointer to new genetlink header.
358 */
359static inline void *
360genlmsg_iput(struct sk_buff *skb, const struct genl_info *info)
361{
362 return __genlmsg_iput(skb, info, 0);
363}
364
365/**
366 * genlmsg_nlhdr - Obtain netlink header from user specified header
367 * @user_hdr: user header as returned from genlmsg_put()
368 *
369 * Returns pointer to netlink header.
370 */
371static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
372{
373 return (struct nlmsghdr *)((char *)user_hdr -
374 GENL_HDRLEN -
375 NLMSG_HDRLEN);
376}
377
378/**
379 * genlmsg_parse_deprecated - parse attributes of a genetlink message
380 * @nlh: netlink message header
381 * @family: genetlink message family
382 * @tb: destination array with maxtype+1 elements
383 * @maxtype: maximum attribute type to be expected
384 * @policy: validation policy
385 * @extack: extended ACK report struct
386 */
387static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
388 const struct genl_family *family,
389 struct nlattr *tb[], int maxtype,
390 const struct nla_policy *policy,
391 struct netlink_ext_ack *extack)
392{
393 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
394 policy, NL_VALIDATE_LIBERAL, extack);
395}
396
397/**
398 * genlmsg_parse - parse attributes of a genetlink message
399 * @nlh: netlink message header
400 * @family: genetlink message family
401 * @tb: destination array with maxtype+1 elements
402 * @maxtype: maximum attribute type to be expected
403 * @policy: validation policy
404 * @extack: extended ACK report struct
405 */
406static inline int genlmsg_parse(const struct nlmsghdr *nlh,
407 const struct genl_family *family,
408 struct nlattr *tb[], int maxtype,
409 const struct nla_policy *policy,
410 struct netlink_ext_ack *extack)
411{
412 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
413 policy, NL_VALIDATE_STRICT, extack);
414}
415
416/**
417 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
418 * @cb: netlink callback structure that stores the sequence number
419 * @user_hdr: user header as returned from genlmsg_put()
420 *
421 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
422 * simpler to use with generic netlink.
423 */
424static inline void genl_dump_check_consistent(struct netlink_callback *cb,
425 void *user_hdr)
426{
427 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
428}
429
430/**
431 * genlmsg_put_reply - Add generic netlink header to a reply message
432 * @skb: socket buffer holding the message
433 * @info: receiver info
434 * @family: generic netlink family
435 * @flags: netlink message flags
436 * @cmd: generic netlink command
437 *
438 * Returns pointer to user specific header
439 */
440static inline void *genlmsg_put_reply(struct sk_buff *skb,
441 struct genl_info *info,
442 const struct genl_family *family,
443 int flags, u8 cmd)
444{
445 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
446 flags, cmd);
447}
448
449/**
450 * genlmsg_end - Finalize a generic netlink message
451 * @skb: socket buffer the message is stored in
452 * @hdr: user specific header
453 */
454static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
455{
456 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
457}
458
459/**
460 * genlmsg_cancel - Cancel construction of a generic netlink message
461 * @skb: socket buffer the message is stored in
462 * @hdr: generic netlink message header
463 */
464static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
465{
466 if (hdr)
467 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
468}
469
470/**
471 * genlmsg_multicast_netns_filtered - multicast a netlink message
472 * to a specific netns with filter
473 * function
474 * @family: the generic netlink family
475 * @net: the net namespace
476 * @skb: netlink message as socket buffer
477 * @portid: own netlink portid to avoid sending to yourself
478 * @group: offset of multicast group in groups array
479 * @flags: allocation flags
480 * @filter: filter function
481 * @filter_data: filter function private data
482 *
483 * Return: 0 on success, negative error code for failure.
484 */
485static inline int
486genlmsg_multicast_netns_filtered(const struct genl_family *family,
487 struct net *net, struct sk_buff *skb,
488 u32 portid, unsigned int group, gfp_t flags,
489 netlink_filter_fn filter,
490 void *filter_data)
491{
492 if (WARN_ON_ONCE(group >= family->n_mcgrps))
493 return -EINVAL;
494 group = family->mcgrp_offset + group;
495 return nlmsg_multicast_filtered(net->genl_sock, skb, portid, group,
496 flags, filter, filter_data);
497}
498
499/**
500 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
501 * @family: the generic netlink family
502 * @net: the net namespace
503 * @skb: netlink message as socket buffer
504 * @portid: own netlink portid to avoid sending to yourself
505 * @group: offset of multicast group in groups array
506 * @flags: allocation flags
507 */
508static inline int genlmsg_multicast_netns(const struct genl_family *family,
509 struct net *net, struct sk_buff *skb,
510 u32 portid, unsigned int group, gfp_t flags)
511{
512 return genlmsg_multicast_netns_filtered(family, net, skb, portid,
513 group, flags, NULL, NULL);
514}
515
516/**
517 * genlmsg_multicast - multicast a netlink message to the default netns
518 * @family: the generic netlink family
519 * @skb: netlink message as socket buffer
520 * @portid: own netlink portid to avoid sending to yourself
521 * @group: offset of multicast group in groups array
522 * @flags: allocation flags
523 */
524static inline int genlmsg_multicast(const struct genl_family *family,
525 struct sk_buff *skb, u32 portid,
526 unsigned int group, gfp_t flags)
527{
528 return genlmsg_multicast_netns(family, &init_net, skb,
529 portid, group, flags);
530}
531
532/**
533 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
534 * @family: the generic netlink family
535 * @skb: netlink message as socket buffer
536 * @portid: own netlink portid to avoid sending to yourself
537 * @group: offset of multicast group in groups array
538 *
539 * This function must hold the RTNL or rcu_read_lock().
540 */
541int genlmsg_multicast_allns(const struct genl_family *family,
542 struct sk_buff *skb, u32 portid,
543 unsigned int group);
544
545/**
546 * genlmsg_unicast - unicast a netlink message
547 * @net: network namespace to look up @portid in
548 * @skb: netlink message as socket buffer
549 * @portid: netlink portid of the destination socket
550 */
551static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
552{
553 return nlmsg_unicast(net->genl_sock, skb, portid);
554}
555
556/**
557 * genlmsg_reply - reply to a request
558 * @skb: netlink message to be sent back
559 * @info: receiver information
560 */
561static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
562{
563 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
564}
565
566/**
567 * genlmsg_data - head of message payload
568 * @gnlh: genetlink message header
569 */
570static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
571{
572 return ((unsigned char *) gnlh + GENL_HDRLEN);
573}
574
575/**
576 * genlmsg_len - length of message payload
577 * @gnlh: genetlink message header
578 */
579static inline int genlmsg_len(const struct genlmsghdr *gnlh)
580{
581 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
582 NLMSG_HDRLEN);
583 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
584}
585
586/**
587 * genlmsg_msg_size - length of genetlink message not including padding
588 * @payload: length of message payload
589 */
590static inline int genlmsg_msg_size(int payload)
591{
592 return GENL_HDRLEN + payload;
593}
594
595/**
596 * genlmsg_total_size - length of genetlink message including padding
597 * @payload: length of message payload
598 */
599static inline int genlmsg_total_size(int payload)
600{
601 return NLMSG_ALIGN(genlmsg_msg_size(payload));
602}
603
604/**
605 * genlmsg_new - Allocate a new generic netlink message
606 * @payload: size of the message payload
607 * @flags: the type of memory to allocate.
608 */
609static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
610{
611 return nlmsg_new(genlmsg_total_size(payload), flags);
612}
613
614/**
615 * genl_set_err - report error to genetlink broadcast listeners
616 * @family: the generic netlink family
617 * @net: the network namespace to report the error to
618 * @portid: the PORTID of a process that we want to skip (if any)
619 * @group: the broadcast group that will notice the error
620 * (this is the offset of the multicast group in the groups array)
621 * @code: error code, must be negative (as usual in kernelspace)
622 *
623 * This function returns the number of broadcast listeners that have set the
624 * NETLINK_RECV_NO_ENOBUFS socket option.
625 */
626static inline int genl_set_err(const struct genl_family *family,
627 struct net *net, u32 portid,
628 u32 group, int code)
629{
630 if (WARN_ON_ONCE(group >= family->n_mcgrps))
631 return -EINVAL;
632 group = family->mcgrp_offset + group;
633 return netlink_set_err(net->genl_sock, portid, group, code);
634}
635
636static inline int genl_has_listeners(const struct genl_family *family,
637 struct net *net, unsigned int group)
638{
639 if (WARN_ON_ONCE(group >= family->n_mcgrps))
640 return -EINVAL;
641 group = family->mcgrp_offset + group;
642 return netlink_has_listeners(net->genl_sock, group);
643}
644#endif /* __NET_GENERIC_NETLINK_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __NET_GENERIC_NETLINK_H
3#define __NET_GENERIC_NETLINK_H
4
5#include <linux/genetlink.h>
6#include <net/netlink.h>
7#include <net/net_namespace.h>
8
9#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
10
11/**
12 * struct genl_multicast_group - generic netlink multicast group
13 * @name: name of the multicast group, names are per-family
14 */
15struct genl_multicast_group {
16 char name[GENL_NAMSIZ];
17};
18
19struct genl_ops;
20struct genl_info;
21
22/**
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 * @mcast_bind: a socket bound to the given multicast group (which
38 * is given as the offset into the groups array)
39 * @mcast_unbind: a socket was unbound from the given multicast group.
40 * Note that unbind() will not be called symmetrically if the
41 * generic netlink family is removed while there are still open
42 * sockets.
43 * @attrbuf: buffer to store parsed attributes (private)
44 * @mcgrps: multicast groups used by this family
45 * @n_mcgrps: number of multicast groups
46 * @mcgrp_offset: starting number of multicast group IDs in this family
47 * (private)
48 * @ops: the operations supported by this family
49 * @n_ops: number of operations supported by this family
50 */
51struct genl_family {
52 int id; /* private */
53 unsigned int hdrsize;
54 char name[GENL_NAMSIZ];
55 unsigned int version;
56 unsigned int maxattr;
57 bool netnsok;
58 bool parallel_ops;
59 int (*pre_doit)(const struct genl_ops *ops,
60 struct sk_buff *skb,
61 struct genl_info *info);
62 void (*post_doit)(const struct genl_ops *ops,
63 struct sk_buff *skb,
64 struct genl_info *info);
65 int (*mcast_bind)(struct net *net, int group);
66 void (*mcast_unbind)(struct net *net, int group);
67 struct nlattr ** attrbuf; /* private */
68 const struct genl_ops * ops;
69 const struct genl_multicast_group *mcgrps;
70 unsigned int n_ops;
71 unsigned int n_mcgrps;
72 unsigned int mcgrp_offset; /* private */
73 struct module *module;
74};
75
76struct nlattr **genl_family_attrbuf(const struct genl_family *family);
77
78/**
79 * struct genl_info - receiving information
80 * @snd_seq: sending sequence number
81 * @snd_portid: netlink portid of sender
82 * @nlhdr: netlink message header
83 * @genlhdr: generic netlink message header
84 * @userhdr: user specific header
85 * @attrs: netlink attributes
86 * @_net: network namespace
87 * @user_ptr: user pointers
88 * @extack: extended ACK report struct
89 */
90struct genl_info {
91 u32 snd_seq;
92 u32 snd_portid;
93 struct nlmsghdr * nlhdr;
94 struct genlmsghdr * genlhdr;
95 void * userhdr;
96 struct nlattr ** attrs;
97 possible_net_t _net;
98 void * user_ptr[2];
99 struct netlink_ext_ack *extack;
100};
101
102static inline struct net *genl_info_net(struct genl_info *info)
103{
104 return read_pnet(&info->_net);
105}
106
107static inline void genl_info_net_set(struct genl_info *info, struct net *net)
108{
109 write_pnet(&info->_net, net);
110}
111
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,
115 struct nlattr *attr)
116{
117 info->extack->bad_attr = attr;
118
119 return err;
120}
121
122/**
123 * struct genl_ops - generic netlink operations
124 * @cmd: command identifier
125 * @internal_flags: flags used by the family
126 * @flags: flags
127 * @policy: attribute validation policy
128 * @doit: standard command callback
129 * @start: start callback for dumps
130 * @dumpit: callback for dumpers
131 * @done: completion callback for dumps
132 */
133struct genl_ops {
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);
141 u8 cmd;
142 u8 internal_flags;
143 u8 flags;
144};
145
146int genl_register_family(struct genl_family *family);
147int genl_unregister_family(const struct genl_family *family);
148void genl_notify(const struct genl_family *family, struct sk_buff *skb,
149 struct genl_info *info, u32 group, gfp_t flags);
150
151void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
152 const struct genl_family *family, int flags, u8 cmd);
153
154/**
155 * genlmsg_nlhdr - Obtain netlink header from user specified header
156 * @user_hdr: user header as returned from genlmsg_put()
157 *
158 * Returns pointer to netlink header.
159 */
160static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
161{
162 return (struct nlmsghdr *)((char *)user_hdr -
163 GENL_HDRLEN -
164 NLMSG_HDRLEN);
165}
166
167/**
168 * genlmsg_parse - parse attributes of a genetlink message
169 * @nlh: netlink message header
170 * @family: genetlink message family
171 * @tb: destination array with maxtype+1 elements
172 * @maxtype: maximum attribute type to be expected
173 * @policy: validation policy
174 * @extack: extended ACK report struct
175 */
176static inline int genlmsg_parse(const struct nlmsghdr *nlh,
177 const struct genl_family *family,
178 struct nlattr *tb[], int maxtype,
179 const struct nla_policy *policy,
180 struct netlink_ext_ack *extack)
181{
182 return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
183 policy, extack);
184}
185
186/**
187 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
188 * @cb: netlink callback structure that stores the sequence number
189 * @user_hdr: user header as returned from genlmsg_put()
190 *
191 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
192 * simpler to use with generic netlink.
193 */
194static inline void genl_dump_check_consistent(struct netlink_callback *cb,
195 void *user_hdr)
196{
197 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
198}
199
200/**
201 * genlmsg_put_reply - Add generic netlink header to a reply message
202 * @skb: socket buffer holding the message
203 * @info: receiver info
204 * @family: generic netlink family
205 * @flags: netlink message flags
206 * @cmd: generic netlink command
207 *
208 * Returns pointer to user specific header
209 */
210static inline void *genlmsg_put_reply(struct sk_buff *skb,
211 struct genl_info *info,
212 const struct genl_family *family,
213 int flags, u8 cmd)
214{
215 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
216 flags, cmd);
217}
218
219/**
220 * genlmsg_end - Finalize a generic netlink message
221 * @skb: socket buffer the message is stored in
222 * @hdr: user specific header
223 */
224static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
225{
226 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
227}
228
229/**
230 * genlmsg_cancel - Cancel construction of a generic netlink message
231 * @skb: socket buffer the message is stored in
232 * @hdr: generic netlink message header
233 */
234static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
235{
236 if (hdr)
237 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
238}
239
240/**
241 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
242 * @family: the generic netlink family
243 * @net: the net namespace
244 * @skb: netlink message as socket buffer
245 * @portid: own netlink portid to avoid sending to yourself
246 * @group: offset of multicast group in groups array
247 * @flags: allocation flags
248 */
249static inline int genlmsg_multicast_netns(const struct genl_family *family,
250 struct net *net, struct sk_buff *skb,
251 u32 portid, unsigned int group, gfp_t flags)
252{
253 if (WARN_ON_ONCE(group >= family->n_mcgrps))
254 return -EINVAL;
255 group = family->mcgrp_offset + group;
256 return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
257}
258
259/**
260 * genlmsg_multicast - multicast a netlink message to the default netns
261 * @family: the generic netlink family
262 * @skb: netlink message as socket buffer
263 * @portid: own netlink portid to avoid sending to yourself
264 * @group: offset of multicast group in groups array
265 * @flags: allocation flags
266 */
267static inline int genlmsg_multicast(const struct genl_family *family,
268 struct sk_buff *skb, u32 portid,
269 unsigned int group, gfp_t flags)
270{
271 return genlmsg_multicast_netns(family, &init_net, skb,
272 portid, group, flags);
273}
274
275/**
276 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
277 * @family: the generic netlink family
278 * @skb: netlink message as socket buffer
279 * @portid: own netlink portid to avoid sending to yourself
280 * @group: offset of multicast group in groups array
281 * @flags: allocation flags
282 *
283 * This function must hold the RTNL or rcu_read_lock().
284 */
285int genlmsg_multicast_allns(const struct genl_family *family,
286 struct sk_buff *skb, u32 portid,
287 unsigned int group, gfp_t flags);
288
289/**
290 * genlmsg_unicast - unicast a netlink message
291 * @skb: netlink message as socket buffer
292 * @portid: netlink portid of the destination socket
293 */
294static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
295{
296 return nlmsg_unicast(net->genl_sock, skb, portid);
297}
298
299/**
300 * genlmsg_reply - reply to a request
301 * @skb: netlink message to be sent back
302 * @info: receiver information
303 */
304static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
305{
306 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
307}
308
309/**
310 * gennlmsg_data - head of message payload
311 * @gnlh: genetlink message header
312 */
313static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
314{
315 return ((unsigned char *) gnlh + GENL_HDRLEN);
316}
317
318/**
319 * genlmsg_len - length of message payload
320 * @gnlh: genetlink message header
321 */
322static inline int genlmsg_len(const struct genlmsghdr *gnlh)
323{
324 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
325 NLMSG_HDRLEN);
326 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
327}
328
329/**
330 * genlmsg_msg_size - length of genetlink message not including padding
331 * @payload: length of message payload
332 */
333static inline int genlmsg_msg_size(int payload)
334{
335 return GENL_HDRLEN + payload;
336}
337
338/**
339 * genlmsg_total_size - length of genetlink message including padding
340 * @payload: length of message payload
341 */
342static inline int genlmsg_total_size(int payload)
343{
344 return NLMSG_ALIGN(genlmsg_msg_size(payload));
345}
346
347/**
348 * genlmsg_new - Allocate a new generic netlink message
349 * @payload: size of the message payload
350 * @flags: the type of memory to allocate.
351 */
352static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
353{
354 return nlmsg_new(genlmsg_total_size(payload), flags);
355}
356
357/**
358 * genl_set_err - report error to genetlink broadcast listeners
359 * @family: the generic netlink family
360 * @net: the network namespace to report the error to
361 * @portid: the PORTID of a process that we want to skip (if any)
362 * @group: the broadcast group that will notice the error
363 * (this is the offset of the multicast group in the groups array)
364 * @code: error code, must be negative (as usual in kernelspace)
365 *
366 * This function returns the number of broadcast listeners that have set the
367 * NETLINK_RECV_NO_ENOBUFS socket option.
368 */
369static inline int genl_set_err(const struct genl_family *family,
370 struct net *net, u32 portid,
371 u32 group, int code)
372{
373 if (WARN_ON_ONCE(group >= family->n_mcgrps))
374 return -EINVAL;
375 group = family->mcgrp_offset + group;
376 return netlink_set_err(net->genl_sock, portid, group, code);
377}
378
379static inline int genl_has_listeners(const struct genl_family *family,
380 struct net *net, unsigned int group)
381{
382 if (WARN_ON_ONCE(group >= family->n_mcgrps))
383 return -EINVAL;
384 group = family->mcgrp_offset + group;
385 return netlink_has_listeners(net->genl_sock, group);
386}
387#endif /* __NET_GENERIC_NETLINK_H */