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