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