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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 * @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 */