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 * @bind: called when family multicast group is added to a netlink socket
45 * @unbind: called when family multicast group is removed from a netlink socket
46 * @module: pointer to the owning module (set to THIS_MODULE)
47 * @mcgrps: multicast groups used by this family
48 * @n_mcgrps: number of multicast groups
49 * @resv_start_op: first operation for which reserved fields of the header
50 * can be validated and policies are required (see below);
51 * new families should leave this field at zero
52 * @ops: the operations supported by this family
53 * @n_ops: number of operations supported by this family
54 * @small_ops: the small-struct operations supported by this family
55 * @n_small_ops: number of small-struct operations supported by this family
56 * @split_ops: the split do/dump form of operation definition
57 * @n_split_ops: number of entries in @split_ops, not that with split do/dump
58 * ops the number of entries is not the same as number of commands
59 * @sock_priv_size: the size of per-socket private memory
60 * @sock_priv_init: the per-socket private memory initializer
61 * @sock_priv_destroy: the per-socket private memory destructor
63 * Attribute policies (the combination of @policy and @maxattr fields)
64 * can be attached at the family level or at the operation level.
65 * If both are present the per-operation policy takes precedence.
66 * For operations before @resv_start_op lack of policy means that the core
67 * will perform no attribute parsing or validation. For newer operations
68 * if policy is not provided core will reject all TLV attributes.
72 char name[GENL_NAMSIZ];
82 const struct nla_policy *policy;
83 int (*pre_doit)(const struct genl_split_ops *ops,
85 struct genl_info *info);
86 void (*post_doit)(const struct genl_split_ops *ops,
88 struct genl_info *info);
89 int (*bind)(int mcgrp);
90 void (*unbind)(int mcgrp);
91 const struct genl_ops * ops;
92 const struct genl_small_ops *small_ops;
93 const struct genl_split_ops *split_ops;
94 const struct genl_multicast_group *mcgrps;
95 struct module *module;
97 size_t sock_priv_size;
98 void (*sock_priv_init)(void *priv);
99 void (*sock_priv_destroy)(void *priv);
101 /* private: internal use only */
102 /* protocol family identifier */
104 /* starting number of multicast group IDs in this family */
105 unsigned int mcgrp_offset;
106 /* list of per-socket privs */
107 struct xarray *sock_privs;
111 * struct genl_info - receiving information
112 * @snd_seq: sending sequence number
113 * @snd_portid: netlink portid of sender
114 * @family: generic netlink family
115 * @nlhdr: netlink message header
116 * @genlhdr: generic netlink message header
117 * @attrs: netlink attributes
118 * @_net: network namespace
119 * @user_ptr: user pointers
120 * @extack: extended ACK report struct
125 const struct genl_family *family;
126 const struct nlmsghdr * nlhdr;
127 struct genlmsghdr * genlhdr;
128 struct nlattr ** attrs;
131 struct netlink_ext_ack *extack;
134 static inline struct net *genl_info_net(const struct genl_info *info)
136 return read_pnet(&info->_net);
139 static inline void genl_info_net_set(struct genl_info *info, struct net *net)
141 write_pnet(&info->_net, net);
144 static inline void *genl_info_userhdr(const struct genl_info *info)
146 return (u8 *)info->genlhdr + GENL_HDRLEN;
149 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)
151 #define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
152 NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)
154 /* Report that a root attribute is missing */
155 #define GENL_REQ_ATTR_CHECK(info, attr) ({ \
156 const struct genl_info *__info = (info); \
158 NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
161 enum genl_validate_flags {
162 GENL_DONT_VALIDATE_STRICT = BIT(0),
163 GENL_DONT_VALIDATE_DUMP = BIT(1),
164 GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
168 * struct genl_small_ops - generic netlink operations (small version)
169 * @cmd: command identifier
170 * @internal_flags: flags used by the family
171 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
172 * @validate: validation flags from enum genl_validate_flags
173 * @doit: standard command callback
174 * @dumpit: callback for dumpers
176 * This is a cut-down version of struct genl_ops for users who don't need
177 * most of the ancillary infra and want to save space.
179 struct genl_small_ops {
180 int (*doit)(struct sk_buff *skb, struct genl_info *info);
181 int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
189 * struct genl_ops - generic netlink operations
190 * @cmd: command identifier
191 * @internal_flags: flags used by the family
192 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
193 * @maxattr: maximum number of attributes supported
194 * @policy: netlink policy (takes precedence over family policy)
195 * @validate: validation flags from enum genl_validate_flags
196 * @doit: standard command callback
197 * @start: start callback for dumps
198 * @dumpit: callback for dumpers
199 * @done: completion callback for dumps
202 int (*doit)(struct sk_buff *skb,
203 struct genl_info *info);
204 int (*start)(struct netlink_callback *cb);
205 int (*dumpit)(struct sk_buff *skb,
206 struct netlink_callback *cb);
207 int (*done)(struct netlink_callback *cb);
208 const struct nla_policy *policy;
209 unsigned int maxattr;
217 * struct genl_split_ops - generic netlink operations (do/dump split version)
218 * @cmd: command identifier
219 * @internal_flags: flags used by the family
220 * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
221 * @validate: validation flags from enum genl_validate_flags
222 * @policy: netlink policy (takes precedence over family policy)
223 * @maxattr: maximum number of attributes supported
226 * @pre_doit: called before an operation's @doit callback, it may
227 * do additional, common, filtering and return an error
228 * @doit: standard command callback
229 * @post_doit: called after an operation's @doit callback, it may
230 * undo operations done by pre_doit, for example release locks
233 * @start: start callback for dumps
234 * @dumpit: callback for dumpers
235 * @done: completion callback for dumps
237 * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
238 * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
239 * Exactly one of those flags must be set.
241 struct genl_split_ops {
244 int (*pre_doit)(const struct genl_split_ops *ops,
246 struct genl_info *info);
247 int (*doit)(struct sk_buff *skb,
248 struct genl_info *info);
249 void (*post_doit)(const struct genl_split_ops *ops,
251 struct genl_info *info);
254 int (*start)(struct netlink_callback *cb);
255 int (*dumpit)(struct sk_buff *skb,
256 struct netlink_callback *cb);
257 int (*done)(struct netlink_callback *cb);
260 const struct nla_policy *policy;
261 unsigned int maxattr;
269 * struct genl_dumpit_info - info that is available during dumpit op call
270 * @op: generic netlink ops - for internal genl code usage
271 * @attrs: netlink attributes
272 * @info: struct genl_info describing the request
274 struct genl_dumpit_info {
275 struct genl_split_ops op;
276 struct genl_info info;
279 static inline const struct genl_dumpit_info *
280 genl_dumpit_info(struct netlink_callback *cb)
285 static inline const struct genl_info *
286 genl_info_dump(struct netlink_callback *cb)
288 return &genl_dumpit_info(cb)->info;
292 * genl_info_init_ntf() - initialize genl_info for notifications
293 * @info: genl_info struct to set up
294 * @family: pointer to the genetlink family
295 * @cmd: command to be used in the notification
297 * Initialize a locally declared struct genl_info to pass to various APIs.
298 * Intended to be used when creating notifications.
301 genl_info_init_ntf(struct genl_info *info, const struct genl_family *family,
304 struct genlmsghdr *hdr = (void *) &info->user_ptr[0];
306 memset(info, 0, sizeof(*info));
307 info->family = family;
312 static inline bool genl_info_is_ntf(const struct genl_info *info)
317 void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk);
318 void *genl_sk_priv_get(struct genl_family *family, struct sock *sk);
319 int genl_register_family(struct genl_family *family);
320 int genl_unregister_family(const struct genl_family *family);
321 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
322 struct genl_info *info, u32 group, gfp_t flags);
324 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
325 const struct genl_family *family, int flags, u8 cmd);
328 __genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags)
330 return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family,
331 flags, info->genlhdr->cmd);
335 * genlmsg_iput - start genetlink message based on genl_info
336 * @skb: skb in which message header will be placed
337 * @info: genl_info as provided to do/dump handlers
339 * Convenience wrapper which starts a genetlink message based on
340 * information in user request. @info should be either the struct passed
341 * by genetlink core to do/dump handlers (when constructing replies to
342 * such requests) or a struct initialized by genl_info_init_ntf()
343 * when constructing notifications.
345 * Returns pointer to new genetlink header.
348 genlmsg_iput(struct sk_buff *skb, const struct genl_info *info)
350 return __genlmsg_iput(skb, info, 0);
354 * genlmsg_nlhdr - Obtain netlink header from user specified header
355 * @user_hdr: user header as returned from genlmsg_put()
357 * Returns pointer to netlink header.
359 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
361 return (struct nlmsghdr *)((char *)user_hdr -
367 * genlmsg_parse_deprecated - parse attributes of a genetlink message
368 * @nlh: netlink message header
369 * @family: genetlink message family
370 * @tb: destination array with maxtype+1 elements
371 * @maxtype: maximum attribute type to be expected
372 * @policy: validation policy
373 * @extack: extended ACK report struct
375 static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
376 const struct genl_family *family,
377 struct nlattr *tb[], int maxtype,
378 const struct nla_policy *policy,
379 struct netlink_ext_ack *extack)
381 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
382 policy, NL_VALIDATE_LIBERAL, extack);
386 * genlmsg_parse - parse attributes of a genetlink message
387 * @nlh: netlink message header
388 * @family: genetlink message family
389 * @tb: destination array with maxtype+1 elements
390 * @maxtype: maximum attribute type to be expected
391 * @policy: validation policy
392 * @extack: extended ACK report struct
394 static inline int genlmsg_parse(const struct nlmsghdr *nlh,
395 const struct genl_family *family,
396 struct nlattr *tb[], int maxtype,
397 const struct nla_policy *policy,
398 struct netlink_ext_ack *extack)
400 return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
401 policy, NL_VALIDATE_STRICT, extack);
405 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
406 * @cb: netlink callback structure that stores the sequence number
407 * @user_hdr: user header as returned from genlmsg_put()
409 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
410 * simpler to use with generic netlink.
412 static inline void genl_dump_check_consistent(struct netlink_callback *cb,
415 nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
419 * genlmsg_put_reply - Add generic netlink header to a reply message
420 * @skb: socket buffer holding the message
421 * @info: receiver info
422 * @family: generic netlink family
423 * @flags: netlink message flags
424 * @cmd: generic netlink command
426 * Returns pointer to user specific header
428 static inline void *genlmsg_put_reply(struct sk_buff *skb,
429 struct genl_info *info,
430 const struct genl_family *family,
433 return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
438 * genlmsg_end - Finalize a generic netlink message
439 * @skb: socket buffer the message is stored in
440 * @hdr: user specific header
442 static inline void genlmsg_end(struct sk_buff *skb, void *hdr)
444 nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
448 * genlmsg_cancel - Cancel construction of a generic netlink message
449 * @skb: socket buffer the message is stored in
450 * @hdr: generic netlink message header
452 static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
455 nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
459 * genlmsg_multicast_netns_filtered - multicast a netlink message
460 * to a specific netns with filter
462 * @family: the generic netlink family
463 * @net: the net namespace
464 * @skb: netlink message as socket buffer
465 * @portid: own netlink portid to avoid sending to yourself
466 * @group: offset of multicast group in groups array
467 * @flags: allocation flags
468 * @filter: filter function
469 * @filter_data: filter function private data
471 * Return: 0 on success, negative error code for failure.
474 genlmsg_multicast_netns_filtered(const struct genl_family *family,
475 struct net *net, struct sk_buff *skb,
476 u32 portid, unsigned int group, gfp_t flags,
477 netlink_filter_fn filter,
480 if (WARN_ON_ONCE(group >= family->n_mcgrps))
482 group = family->mcgrp_offset + group;
483 return nlmsg_multicast_filtered(net->genl_sock, skb, portid, group,
484 flags, filter, filter_data);
488 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
489 * @family: the generic netlink family
490 * @net: the net namespace
491 * @skb: netlink message as socket buffer
492 * @portid: own netlink portid to avoid sending to yourself
493 * @group: offset of multicast group in groups array
494 * @flags: allocation flags
496 static inline int genlmsg_multicast_netns(const struct genl_family *family,
497 struct net *net, struct sk_buff *skb,
498 u32 portid, unsigned int group, gfp_t flags)
500 return genlmsg_multicast_netns_filtered(family, net, skb, portid,
501 group, flags, NULL, NULL);
505 * genlmsg_multicast - multicast a netlink message to the default netns
506 * @family: the generic netlink family
507 * @skb: netlink message as socket buffer
508 * @portid: own netlink portid to avoid sending to yourself
509 * @group: offset of multicast group in groups array
510 * @flags: allocation flags
512 static inline int genlmsg_multicast(const struct genl_family *family,
513 struct sk_buff *skb, u32 portid,
514 unsigned int group, gfp_t flags)
516 return genlmsg_multicast_netns(family, &init_net, skb,
517 portid, group, flags);
521 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
522 * @family: the generic netlink family
523 * @skb: netlink message as socket buffer
524 * @portid: own netlink portid to avoid sending to yourself
525 * @group: offset of multicast group in groups array
526 * @flags: allocation flags
528 * This function must hold the RTNL or rcu_read_lock().
530 int genlmsg_multicast_allns(const struct genl_family *family,
531 struct sk_buff *skb, u32 portid,
532 unsigned int group, gfp_t flags);
535 * genlmsg_unicast - unicast a netlink message
536 * @net: network namespace to look up @portid in
537 * @skb: netlink message as socket buffer
538 * @portid: netlink portid of the destination socket
540 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
542 return nlmsg_unicast(net->genl_sock, skb, portid);
546 * genlmsg_reply - reply to a request
547 * @skb: netlink message to be sent back
548 * @info: receiver information
550 static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
552 return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
556 * genlmsg_data - head of message payload
557 * @gnlh: genetlink message header
559 static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
561 return ((unsigned char *) gnlh + GENL_HDRLEN);
565 * genlmsg_len - length of message payload
566 * @gnlh: genetlink message header
568 static inline int genlmsg_len(const struct genlmsghdr *gnlh)
570 struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
572 return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
576 * genlmsg_msg_size - length of genetlink message not including padding
577 * @payload: length of message payload
579 static inline int genlmsg_msg_size(int payload)
581 return GENL_HDRLEN + payload;
585 * genlmsg_total_size - length of genetlink message including padding
586 * @payload: length of message payload
588 static inline int genlmsg_total_size(int payload)
590 return NLMSG_ALIGN(genlmsg_msg_size(payload));
594 * genlmsg_new - Allocate a new generic netlink message
595 * @payload: size of the message payload
596 * @flags: the type of memory to allocate.
598 static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
600 return nlmsg_new(genlmsg_total_size(payload), flags);
604 * genl_set_err - report error to genetlink broadcast listeners
605 * @family: the generic netlink family
606 * @net: the network namespace to report the error to
607 * @portid: the PORTID of a process that we want to skip (if any)
608 * @group: the broadcast group that will notice the error
609 * (this is the offset of the multicast group in the groups array)
610 * @code: error code, must be negative (as usual in kernelspace)
612 * This function returns the number of broadcast listeners that have set the
613 * NETLINK_RECV_NO_ENOBUFS socket option.
615 static inline int genl_set_err(const struct genl_family *family,
616 struct net *net, u32 portid,
619 if (WARN_ON_ONCE(group >= family->n_mcgrps))
621 group = family->mcgrp_offset + group;
622 return netlink_set_err(net->genl_sock, portid, group, code);
625 static inline int genl_has_listeners(const struct genl_family *family,
626 struct net *net, unsigned int group)
628 if (WARN_ON_ONCE(group >= family->n_mcgrps))
630 group = family->mcgrp_offset + group;
631 return netlink_has_listeners(net->genl_sock, group);
633 #endif /* __NET_GENERIC_NETLINK_H */