aboutsummaryrefslogtreecommitdiff
path: root/include/net/genetlink.h
blob: ace4abf118d7d4b0501fa3c6829001da905e728b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
#ifndef __NET_GENERIC_NETLINK_H
#define __NET_GENERIC_NETLINK_H

#include <linux/genetlink.h>
#include <net/netlink.h>
#include <net/net_namespace.h>

#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)

/**
 * struct genl_multicast_group - generic netlink multicast group
 * @name: name of the multicast group, names are per-family
 */
struct genl_multicast_group {
	char			name[GENL_NAMSIZ];
};

struct genl_ops;
struct genl_info;

/**
 * struct genl_family - generic netlink family
 * @id: protocol family idenfitier
 * @hdrsize: length of user specific header in bytes
 * @name: name of family
 * @version: protocol version
 * @maxattr: maximum number of attributes supported
 * @netnsok: set to true if the family can handle network
 *	namespaces and should be presented in all of them
 * @pre_doit: called before an operation's doit callback, it may
 *	do additional, common, filtering and return an error
 * @post_doit: called after an operation's doit callback, it may
 *	undo operations done by pre_doit, for example release locks
 * @attrbuf: buffer to store parsed attributes
 * @family_list: family list
 * @mcgrps: multicast groups used by this family (private)
 * @n_mcgrps: number of multicast groups (private)
 * @mcgrp_offset: starting number of multicast group IDs in this family
 * @ops: the operations supported by this family (private)
 * @n_ops: number of operations supported by this family (private)
 */
struct genl_family {
	unsigned int		id;
	unsigned int		hdrsize;
	char			name[GENL_NAMSIZ];
	unsigned int		version;
	unsigned int		maxattr;
	bool			netnsok;
	bool			parallel_ops;
	int			(*pre_doit)(const struct genl_ops *ops,
					    struct sk_buff *skb,
					    struct genl_info *info);
	void			(*post_doit)(const struct genl_ops *ops,
					     struct sk_buff *skb,
					     struct genl_info *info);
	struct nlattr **	attrbuf;	/* private */
	const struct genl_ops *	ops;		/* private */
	const struct genl_multicast_group *mcgrps; /* private */
	unsigned int		n_ops;		/* private */
	unsigned int		n_mcgrps;	/* private */
	unsigned int		mcgrp_offset;	/* private */
	struct list_head	family_list;	/* private */
	struct module		*module;
};

/**
 * struct genl_info - receiving information
 * @snd_seq: sending sequence number
 * @snd_portid: netlink portid of sender
 * @nlhdr: netlink message header
 * @genlhdr: generic netlink message header
 * @userhdr: user specific header
 * @attrs: netlink attributes
 * @_net: network namespace
 * @user_ptr: user pointers
 */
struct genl_info {
	u32			snd_seq;
	u32			snd_portid;
	struct nlmsghdr *	nlhdr;
	struct genlmsghdr *	genlhdr;
	void *			userhdr;
	struct nlattr **	attrs;
#ifdef CONFIG_NET_NS
	struct net *		_net;
#endif
	void *			user_ptr[2];
};

static inline struct net *genl_info_net(struct genl_info *info)
{
	return read_pnet(&info->_net);
}

static inline void genl_info_net_set(struct genl_info *info, struct net *net)
{
	write_pnet(&info->_net, net);
}

/**
 * struct genl_ops - generic netlink operations
 * @cmd: command identifier
 * @internal_flags: flags used by the family
 * @flags: flags
 * @policy: attribute validation policy
 * @doit: standard command callback
 * @dumpit: callback for dumpers
 * @done: completion callback for dumps
 * @ops_list: operations list
 */
struct genl_ops {
	const struct nla_policy	*policy;
	int		       (*doit)(struct sk_buff *skb,
				       struct genl_info *info);
	int		       (*dumpit)(struct sk_buff *skb,
					 struct netlink_callback *cb);
	int		       (*done)(struct netlink_callback *cb);
	u8			cmd;
	u8			internal_flags;
	u8			flags;
};

int __genl_register_family(struct genl_family *family);

static inline int genl_register_family(struct genl_family *family)
{
	family->module = THIS_MODULE;
	return __genl_register_family(family);
}

/**
 * genl_register_family_with_ops - register a generic netlink family with ops
 * @family: generic netlink family
 * @ops: operations to be registered
 * @n_ops: number of elements to register
 *
 * Registers the specified family and operations from the specified table.
 * Only one family may be registered with the same family name or identifier.
 *
 * The family id may equal GENL_ID_GENERATE causing an unique id to
 * be automatically generated and assigned.
 *
 * Either a doit or dumpit callback must be specified for every registered
 * operation or the function will fail. Only one operation structure per
 * command identifier may be registered.
 *
 * See include/net/genetlink.h for more documenation on the operations
 * structure.
 *
 * Return 0 on success or a negative error code.
 */
static inline int
_genl_register_family_with_ops_grps(struct genl_family *family,
				    const struct genl_ops *ops, size_t n_ops,
				    const struct genl_multicast_group *mcgrps,
				    size_t n_mcgrps)
{
	family->module = THIS_MODULE;
	family->ops = ops;
	family->n_ops = n_ops;
	family->mcgrps = mcgrps;
	family->n_mcgrps = n_mcgrps;
	return __genl_register_family(family);
}

#define genl_register_family_with_ops(family, ops)			\
	_genl_register_family_with_ops_grps((family),			\
					    (ops), ARRAY_SIZE(ops),	\
					    NULL, 0)
#define genl_register_family_with_ops_groups(family, ops, grps)	\
	_genl_register_family_with_ops_grps((family),			\
					    (ops), ARRAY_SIZE(ops),	\
					    (grps), ARRAY_SIZE(grps))

int genl_unregister_family(struct genl_family *family);
void genl_notify(struct genl_family *family,
		 struct sk_buff *skb, struct net *net, u32 portid,
		 u32 group, struct nlmsghdr *nlh, gfp_t flags);

void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
		  struct genl_family *family, int flags, u8 cmd);

/**
 * genlmsg_nlhdr - Obtain netlink header from user specified header
 * @user_hdr: user header as returned from genlmsg_put()
 * @family: generic netlink family
 *
 * Returns pointer to netlink header.
 */
static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
					     struct genl_family *family)
{
	return (struct nlmsghdr *)((char *)user_hdr -
				   family->hdrsize -
				   GENL_HDRLEN -
				   NLMSG_HDRLEN);
}

/**
 * genl_dump_check_consistent - check if sequence is consistent and advertise if not
 * @cb: netlink callback structure that stores the sequence number
 * @user_hdr: user header as returned from genlmsg_put()
 * @family: generic netlink family
 *
 * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
 * simpler to use with generic netlink.
 */
static inline void genl_dump_check_consistent(struct netlink_callback *cb,
					      void *user_hdr,
					      struct genl_family *family)
{
	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
}

/**
 * genlmsg_put_reply - Add generic netlink header to a reply message
 * @skb: socket buffer holding the message
 * @info: receiver info
 * @family: generic netlink family
 * @flags: netlink message flags
 * @cmd: generic netlink command
 *
 * Returns pointer to user specific header
 */
static inline void *genlmsg_put_reply(struct sk_buff *skb,
				      struct genl_info *info,
				      struct genl_family *family,
				      int flags, u8 cmd)
{
	return genlmsg_put(skb, info->snd_portid, info->snd_seq, family,
			   flags, cmd);
}

/**
 * genlmsg_end - Finalize a generic netlink message
 * @skb: socket buffer the message is stored in
 * @hdr: user specific header
 */
static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
{
	return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
}

/**
 * genlmsg_cancel - Cancel construction of a generic netlink message
 * @skb: socket buffer the message is stored in
 * @hdr: generic netlink message header
 */
static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)
{
	if (hdr)
		nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
}

/**
 * genlmsg_multicast_netns - multicast a netlink message to a specific netns
 * @family: the generic netlink family
 * @net: the net namespace
 * @skb: netlink message as socket buffer
 * @portid: own netlink portid to avoid sending to yourself
 * @group: offset of multicast group in groups array
 * @flags: allocation flags
 */
static inline int genlmsg_multicast_netns(struct genl_family *family,
					  struct net *net, struct sk_buff *skb,
					  u32 portid, unsigned int group, gfp_t flags)
{
	if (group >= family->n_mcgrps)
		return -EINVAL;
	group = family->mcgrp_offset + group;
	return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
}

/**
 * genlmsg_multicast - multicast a netlink message to the default netns
 * @family: the generic netlink family
 * @skb: netlink message as socket buffer
 * @portid: own netlink portid to avoid sending to yourself
 * @group: offset of multicast group in groups array
 * @flags: allocation flags
 */
static inline int genlmsg_multicast(struct genl_family *family,
				    struct sk_buff *skb, u32 portid,
				    unsigned int group, gfp_t flags)
{
	if (group >= family->n_mcgrps)
		return -EINVAL;
	group = family->mcgrp_offset + group;
	return genlmsg_multicast_netns(family, &init_net, skb,
				       portid, group, flags);
}

/**
 * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
 * @family: the generic netlink family
 * @skb: netlink message as socket buffer
 * @portid: own netlink portid to avoid sending to yourself
 * @group: offset of multicast group in groups array
 * @flags: allocation flags
 *
 * This function must hold the RTNL or rcu_read_lock().
 */
int genlmsg_multicast_allns(struct genl_family *family,
			    struct sk_buff *skb, u32 portid,
			    unsigned int group, gfp_t flags);

/**
 * genlmsg_unicast - unicast a netlink message
 * @skb: netlink message as socket buffer
 * @portid: netlink portid of the destination socket
 */
static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
{
	return nlmsg_unicast(net->genl_sock, skb, portid);
}

/**
 * genlmsg_reply - reply to a request
 * @skb: netlink message to be sent back
 * @info: receiver information
 */
static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
{
	return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid);
}

/**
 * gennlmsg_data - head of message payload
 * @gnlh: genetlink message header
 */
static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
{
	return ((unsigned char *) gnlh + GENL_HDRLEN);
}

/**
 * genlmsg_len - length of message payload
 * @gnlh: genetlink message header
 */
static inline int genlmsg_len(const struct genlmsghdr *gnlh)
{
	struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
							NLMSG_HDRLEN);
	return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
}

/**
 * genlmsg_msg_size - length of genetlink message not including padding
 * @payload: length of message payload
 */
static inline int genlmsg_msg_size(int payload)
{
	return GENL_HDRLEN + payload;
}

/**
 * genlmsg_total_size - length of genetlink message including padding
 * @payload: length of message payload
 */
static inline int genlmsg_total_size(int payload)
{
	return NLMSG_ALIGN(genlmsg_msg_size(payload));
}

/**
 * genlmsg_new - Allocate a new generic netlink message
 * @payload: size of the message payload
 * @flags: the type of memory to allocate.
 */
static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
{
	return nlmsg_new(genlmsg_total_size(payload), flags);
}

/**
 * genl_set_err - report error to genetlink broadcast listeners
 * @family: the generic netlink family
 * @net: the network namespace to report the error to
 * @portid: the PORTID of a process that we want to skip (if any)
 * @group: the broadcast group that will notice the error
 * 	(this is the offset of the multicast group in the groups array)
 * @code: error code, must be negative (as usual in kernelspace)
 *
 * This function returns the number of broadcast listeners that have set the
 * NETLINK_RECV_NO_ENOBUFS socket option.
 */
static inline int genl_set_err(struct genl_family *family, struct net *net,
			       u32 portid, u32 group, int code)
{
	return netlink_set_err(net->genl_sock, portid, group, code);
}

#endif	/* __NET_GENERIC_NETLINK_H */