summaryrefslogtreecommitdiff
path: root/include/linux/genl_magic_struct.h
blob: 9a605b9ee8348406a1bbef7e94214806480c6dbb (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
#ifndef GENL_MAGIC_STRUCT_H
#define GENL_MAGIC_STRUCT_H

#ifndef GENL_MAGIC_FAMILY
# error "you need to define GENL_MAGIC_FAMILY before inclusion"
#endif

#ifndef GENL_MAGIC_VERSION
# error "you need to define GENL_MAGIC_VERSION before inclusion"
#endif

#ifndef GENL_MAGIC_INCLUDE_FILE
# error "you need to define GENL_MAGIC_INCLUDE_FILE before inclusion"
#endif

#include <linux/genetlink.h>
#include <linux/types.h>

#define CONCAT__(a,b)	a ## b
#define CONCAT_(a,b)	CONCAT__(a,b)

extern int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void);
extern void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void);

/*
 * Extension of genl attribute validation policies			{{{2
 */

/**
 * GENLA_F_FLAGS - policy type flags to ease compatible ABI evolvement
 *
 * @GENLA_F_REQUIRED: attribute has to be present, or message is considered invalid.
 * Adding new REQUIRED attributes breaks ABI compatibility, so don't do that.
 *
 * @GENLA_F_MANDATORY: if present, receiver _must_ understand it.
 * Without this, unknown attributes (> maxtype) are _silently_ ignored
 * by validate_nla().
 *
 * To be used for API extensions, so older kernel can reject requests for not
 * yet implemented features, if newer userland tries to use them even though
 * the genl_family version clearly indicates they are not available.
 *
 * @GENLA_F_MAY_IGNORE: To clearly document the fact, for good measure.
 * To be used for API extensions for things that have sane defaults,
 * so newer userland can still talk to older kernel, knowing it will
 * silently ignore these attributes if not yet known.
 *
 * NOTE: These flags overload
 *   NLA_F_NESTED		(1 << 15)
 *   NLA_F_NET_BYTEORDER	(1 << 14)
 * from linux/netlink.h, which are not useful for validate_nla():
 * NET_BYTEORDER is not used anywhere, and NESTED would be specified by setting
 * .type = NLA_NESTED in the appropriate policy.
 *
 * See also: nla_type()
 */
enum {
	GENLA_F_MAY_IGNORE	= 0,
	GENLA_F_MANDATORY	= 1 << 14,
	GENLA_F_REQUIRED	= 1 << 15,

	/* Below will not be present in the __u16 .nla_type, but can be
	 * triggered on in <struct>_to_skb resp. <struct>_from_attrs */

	/* To exclude "sensitive" information from broadcasts, or on
	 * unpriviledged get requests.  This is useful because genetlink
	 * multicast groups can be listened in on by anyone.  */
	GENLA_F_SENSITIVE	= 1 << 16,

	/* INVARIAN options cannot be changed at runtime.
	 * Useful to share an attribute policy and struct definition,
	 * between some "create" and "change" commands,
	 * but disallow certain fields to be changed online.
	 */
	GENLA_F_INVARIANT	= 1 << 17,
};

#define __nla_type(x)	((__u16)((__u16)(x) & (__u16)NLA_TYPE_MASK))

/*									}}}1
 * MAGIC
 * multi-include macro expansion magic starts here
 */

/* MAGIC helpers							{{{2 */

/* possible field types */
#define __flg_field(attr_nr, attr_flag, name) \
	__field(attr_nr, attr_flag, name, NLA_FLAG, char, \
			nla_get_flag, __nla_put_flag)
#define __u8_field(attr_nr, attr_flag, name)	\
	__field(attr_nr, attr_flag, name, NLA_U8, unsigned char, \
			nla_get_u8, NLA_PUT_U8)
#define __u16_field(attr_nr, attr_flag, name)	\
	__field(attr_nr, attr_flag, name, NLA_U16, __u16, \
			nla_get_u16, NLA_PUT_U16)
#define __u32_field(attr_nr, attr_flag, name)	\
	__field(attr_nr, attr_flag, name, NLA_U32, __u32, \
			nla_get_u32, NLA_PUT_U32)
#define __u64_field(attr_nr, attr_flag, name)	\
	__field(attr_nr, attr_flag, name, NLA_U64, __u64, \
			nla_get_u64, NLA_PUT_U64)
#define __str_field(attr_nr, attr_flag, name, maxlen) \
	__array(attr_nr, attr_flag, name, NLA_NUL_STRING, char, maxlen, \
			nla_strlcpy, NLA_PUT)
#define __bin_field(attr_nr, attr_flag, name, maxlen) \
	__array(attr_nr, attr_flag, name, NLA_BINARY, char, maxlen, \
			nla_memcpy, NLA_PUT)

#define __nla_put_flag(skb, attrtype, value)		\
	do {						\
		if (value)				\
			NLA_PUT_FLAG(skb, attrtype);	\
	} while (0)

#define GENL_op_init(args...)	args
#define GENL_doit(handler)		\
	.doit = handler,		\
	.flags = GENL_ADMIN_PERM,
#define GENL_dumpit(handler)		\
	.dumpit = handler,		\
	.flags = GENL_ADMIN_PERM,

/*									}}}1
 * Magic: define the enum symbols for genl_ops
 * Magic: define the enum symbols for top level attributes
 * Magic: define the enum symbols for nested attributes
 *									{{{2
 */

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields)

#undef GENL_mc_group
#define GENL_mc_group(group)

#undef GENL_notification
#define GENL_notification(op_name, op_num, mcast_group, tla_list)	\
	op_name = op_num,

#undef GENL_op
#define GENL_op(op_name, op_num, handler, tla_list)			\
	op_name = op_num,

enum {
#include GENL_MAGIC_INCLUDE_FILE
};

#undef GENL_notification
#define GENL_notification(op_name, op_num, mcast_group, tla_list)

#undef GENL_op
#define GENL_op(op_name, op_num, handler, attr_list)

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
		tag_name = tag_number,

enum {
#include GENL_MAGIC_INCLUDE_FILE
};

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields)	\
enum {								\
	s_fields						\
};

#undef __field
#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put)	\
	T_ ## name = (__u16)(attr_nr | attr_flag),

#undef __array
#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
	T_ ## name = (__u16)(attr_nr | attr_flag),

#include GENL_MAGIC_INCLUDE_FILE

/*									}}}1
 * Magic: compile time assert unique numbers for operations
 * Magic: -"- unique numbers for top level attributes
 * Magic: -"- unique numbers for nested attributes
 *									{{{2
 */

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields)

#undef GENL_op
#define GENL_op(op_name, op_num, handler, attr_list)	\
	case op_name:

#undef GENL_notification
#define GENL_notification(op_name, op_num, mcast_group, tla_list)	\
	case op_name:

static inline void ct_assert_unique_operations(void)
{
	switch (0) {
#include GENL_MAGIC_INCLUDE_FILE
		;
	}
}

#undef GENL_op
#define GENL_op(op_name, op_num, handler, attr_list)

#undef GENL_notification
#define GENL_notification(op_name, op_num, mcast_group, tla_list)

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields)		\
		case tag_number:

static inline void ct_assert_unique_top_level_attributes(void)
{
	switch (0) {
#include GENL_MAGIC_INCLUDE_FILE
		;
	}
}

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields)		\
static inline void ct_assert_unique_ ## s_name ## _attributes(void)	\
{									\
	switch (0) {							\
		s_fields						\
			;						\
	}								\
}

#undef __field
#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put)	\
	case attr_nr:

#undef __array
#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
	case attr_nr:

#include GENL_MAGIC_INCLUDE_FILE

/*									}}}1
 * Magic: declare structs
 * struct <name> {
 *	fields
 * };
 *									{{{2
 */

#undef GENL_struct
#define GENL_struct(tag_name, tag_number, s_name, s_fields)		\
struct s_name { s_fields };

#undef __field
#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
	type name;

#undef __array
#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
	type name[maxlen];	\
	__u32 name ## _len;

#include GENL_MAGIC_INCLUDE_FILE

/* }}}1 */
#endif /* GENL_MAGIC_STRUCT_H */
/* vim: set foldmethod=marker nofoldenable : */