1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_GENERIC_NETLINK_H
3 #define __NET_GENERIC_NETLINK_H
5 #include <linux/genetlink.h>
6 #include <net/netlink.h>
7 #include <net/net_namespace.h>
9 #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)
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)
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
21 struct genl_multicast_group {
22 char name[GENL_NAMSIZ];
26 struct genl_split_ops;
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
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.
70 char name[GENL_NAMSIZ];
80 const struct nla_policy *policy;
81 int (*pre_doit)(const struct genl_split_ops *ops,
83 struct genl_info *info);
84 void (*post_doit)(const struct genl_split_ops *ops,
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;
93 size_t sock_priv_size;
94 void (*sock_priv_init)(void *priv);
95 void (*sock_priv_destroy)(void *priv);
97 /* private: internal use only */
98 /* protocol family identifier */
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;
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
121 const struct genl_family *family;
122 const struct nlmsghdr * nlhdr;
123 struct genlmsghdr * genlhdr;
124 struct nlattr ** attrs;
127 struct netlink_ext_ack *extack;
130 static inline struct net *genl_info_net(const struct genl_info *info)
132 return read_pnet(&info->_net);
135 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
137 write_pnet(&info->_net, net);
140 static inline void *genl_info_userhdr(const struct genl_info *info)
142 return (u8 *)info->genlhdr + GENL_HDRLEN;
145 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
147 #define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
148 NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)
150 /* Report that a root attribute is missing */
151 #define GENL_REQ_ATTR_CHECK(info, attr) ({ \
152 struct genl_info *__info = (info); \
154 NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
157 enum 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),
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
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.
175 struct 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);
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
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;
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
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
229 * @start: start callback for dumps
230 * @dumpit: callback for dumpers
231 * @done: completion callback for dumps
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.
237 struct genl_split_ops {
240 int (*pre_doit)(const struct genl_split_ops *ops,
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,
247 struct genl_info *info);
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);
256 const struct nla_policy *policy;
257 unsigned int maxattr;
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
270 struct genl_dumpit_info {
271 struct genl_split_ops op;
272 struct genl_info info;
275 static inline const struct genl_dumpit_info *
276 genl_dumpit_info(struct netlink_callback *cb)
281 static inline const struct genl_info *
282 genl_info_dump(struct netlink_callback *cb)
284 return &genl_dumpit_info(cb)->info;
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
293 * Initialize a locally declared struct genl_info to pass to various APIs.
294 * Intended to be used when creating notifications.
297 genl_info_init_ntf(struct genl_info *info, const struct genl_family *family,
300 struct genlmsghdr *hdr = (void *) &info->user_ptr[0];
302 memset(info, 0, sizeof(*info));
303 info->family = family;
308 static inline bool genl_info_is_ntf(const struct genl_info *info)
313 void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk);
314 void *genl_sk_priv_get(struct genl_family *family, struct sock *sk);
315 int genl_register_family(struct genl_family *family);
316 int genl_unregister_family(const struct genl_family *family);
317 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
318 struct genl_info *info, u32 group, gfp_t flags);
320 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
321 const struct genl_family *family, int flags, u8 cmd);
324 __genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags)
326 return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family,
327 flags, info->genlhdr->cmd);
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
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.
341 * Returns pointer to new genetlink header.
344 genlmsg_iput(struct sk_buff *skb, const struct genl_info *info)
346 return __genlmsg_iput(skb, info, 0);
350 * genlmsg_nlhdr - Obtain netlink header from user specified header
351 * @user_hdr: user header as returned from genlmsg_put()
353 * Returns pointer to netlink header.
355 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
357 return (struct nlmsghdr *)((char *)user_hdr -
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
371 static 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)
377 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
378 policy, NL_VALIDATE_LIBERAL, extack);
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
390 static 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)
396 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
397 policy, NL_VALIDATE_STRICT, extack);
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()
405 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
406 * simpler to use with generic netlink.
408 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
411 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
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
422 * Returns pointer to user specific header
424 static inline void *genlmsg_put_reply(struct sk_buff *skb,
425 struct genl_info *info,
426 const struct genl_family *family,
429 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
434 * genlmsg_end - Finalize a generic netlink message
435 * @skb: socket buffer the message is stored in
436 * @hdr: user specific header
438 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
440 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
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
448 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
451 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
455 * genlmsg_multicast_netns_filtered - multicast a netlink message
456 * to a specific netns with filter
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
467 * Return: 0 on success, negative error code for failure.
470 genlmsg_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,
476 if (WARN_ON_ONCE(group >= family->n_mcgrps))
478 group = family->mcgrp_offset + group;
479 return nlmsg_multicast_filtered(net->genl_sock, skb, portid, group,
480 flags, filter, filter_data);
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
492 static 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)
496 return genlmsg_multicast_netns_filtered(family, net, skb, portid,
497 group, flags, NULL, NULL);
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
508 static inline int genlmsg_multicast(const struct genl_family *family,
509 struct sk_buff *skb, u32 portid,
510 unsigned int group, gfp_t flags)
512 return genlmsg_multicast_netns(family, &init_net, skb,
513 portid, group, flags);
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
524 * This function must hold the RTNL or rcu_read_lock().
526 int genlmsg_multicast_allns(const struct genl_family *family,
527 struct sk_buff *skb, u32 portid,
528 unsigned int group, gfp_t flags);
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
536 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
538 return nlmsg_unicast(net->genl_sock, skb, portid);
542 * genlmsg_reply - reply to a request
543 * @skb: netlink message to be sent back
544 * @info: receiver information
546 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
548 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
552 * genlmsg_data - head of message payload
553 * @gnlh: genetlink message header
555 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
557 return ((unsigned char *) gnlh + GENL_HDRLEN);
561 * genlmsg_len - length of message payload
562 * @gnlh: genetlink message header
564 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
566 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
568 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
572 * genlmsg_msg_size - length of genetlink message not including padding
573 * @payload: length of message payload
575 static inline int genlmsg_msg_size(int payload)
577 return GENL_HDRLEN + payload;
581 * genlmsg_total_size - length of genetlink message including padding
582 * @payload: length of message payload
584 static inline int genlmsg_total_size(int payload)
586 return NLMSG_ALIGN(genlmsg_msg_size(payload));
590 * genlmsg_new - Allocate a new generic netlink message
591 * @payload: size of the message payload
592 * @flags: the type of memory to allocate.
594 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
596 return nlmsg_new(genlmsg_total_size(payload), flags);
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)
608 * This function returns the number of broadcast listeners that have set the
609 * NETLINK_RECV_NO_ENOBUFS socket option.
611 static inline int genl_set_err(const struct genl_family *family,
612 struct net *net, u32 portid,
615 if (WARN_ON_ONCE(group >= family->n_mcgrps))
617 group = family->mcgrp_offset + group;
618 return netlink_set_err(net->genl_sock, portid, group, code);
621 static inline int genl_has_listeners(const struct genl_family *family,
622 struct net *net, unsigned int group)
624 if (WARN_ON_ONCE(group >= family->n_mcgrps))
626 group = family->mcgrp_offset + group;
627 return netlink_has_listeners(net->genl_sock, group);
629 #endif /* __NET_GENERIC_NETLINK_H */