1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef GENL_MAGIC_FUNC_H
3 #define GENL_MAGIC_FUNC_H
4
5 #include <linux/args.h>
6 #include <linux/build_bug.h>
7 #include <linux/genl_magic_struct.h>
8
9 /*
10 * Magic: declare tla policy {{{1
11 * Magic: declare nested policies
12 * {{{2
13 */
14 #undef GENL_mc_group
15 #define GENL_mc_group(group)
16
17 #undef GENL_notification
18 #define GENL_notification(op_name, op_num, mcast_group, tla_list)
19
20 #undef GENL_op
21 #define GENL_op(op_name, op_num, handler, tla_list)
22
23 #undef GENL_struct
24 #define GENL_struct(tag_name, tag_number, s_name, s_fields) \
25 [tag_name] = { .type = NLA_NESTED },
26
27 static struct nla_policy CONCATENATE(GENL_MAGIC_FAMILY, _tla_nl_policy)[] = {
28 #include GENL_MAGIC_INCLUDE_FILE
29 };
30
31 #undef GENL_struct
32 #define GENL_struct(tag_name, tag_number, s_name, s_fields) \
33 static struct nla_policy s_name ## _nl_policy[] __read_mostly = \
34 { s_fields };
35
36 #undef __field
37 #define __field(attr_nr, attr_flag, name, nla_type, _type, __get, \
38 __put, __is_signed) \
39 [attr_nr] = { .type = nla_type },
40
41 #undef __array
42 #define __array(attr_nr, attr_flag, name, nla_type, _type, maxlen, \
43 __get, __put, __is_signed) \
44 [attr_nr] = { .type = nla_type, \
45 .len = maxlen - (nla_type == NLA_NUL_STRING) },
46
47 #include GENL_MAGIC_INCLUDE_FILE
48
49 #ifndef __KERNEL__
50 #ifndef pr_info
51 #define pr_info(args...) fprintf(stderr, args);
52 #endif
53 #endif
54
55 #ifdef GENL_MAGIC_DEBUG
dprint_field(const char * dir,int nla_type,const char * name,void * valp)56 static void dprint_field(const char *dir, int nla_type,
57 const char *name, void *valp)
58 {
59 __u64 val = valp ? *(__u32 *)valp : 1;
60 switch (nla_type) {
61 case NLA_U8: val = (__u8)val;
62 case NLA_U16: val = (__u16)val;
63 case NLA_U32: val = (__u32)val;
64 pr_info("%s attr %s: %d 0x%08x\n", dir,
65 name, (int)val, (unsigned)val);
66 break;
67 case NLA_U64:
68 val = *(__u64*)valp;
69 pr_info("%s attr %s: %lld 0x%08llx\n", dir,
70 name, (long long)val, (unsigned long long)val);
71 break;
72 case NLA_FLAG:
73 if (val)
74 pr_info("%s attr %s: set\n", dir, name);
75 break;
76 }
77 }
78
dprint_array(const char * dir,int nla_type,const char * name,const char * val,unsigned len)79 static void dprint_array(const char *dir, int nla_type,
80 const char *name, const char *val, unsigned len)
81 {
82 switch (nla_type) {
83 case NLA_NUL_STRING:
84 if (len && val[len-1] == '\0')
85 len--;
86 pr_info("%s attr %s: [len:%u] '%s'\n", dir, name, len, val);
87 break;
88 default:
89 /* we can always show 4 byte,
90 * thats what nlattr are aligned to. */
91 pr_info("%s attr %s: [len:%u] %02x%02x%02x%02x ...\n",
92 dir, name, len, val[0], val[1], val[2], val[3]);
93 }
94 }
95
96 #define DPRINT_TLA(a, op, b) pr_info("%s %s %s\n", a, op, b);
97
98 /* Name is a member field name of the struct s.
99 * If s is NULL (only parsing, no copy requested in *_from_attrs()),
100 * nla is supposed to point to the attribute containing the information
101 * corresponding to that struct member. */
102 #define DPRINT_FIELD(dir, nla_type, name, s, nla) \
103 do { \
104 if (s) \
105 dprint_field(dir, nla_type, #name, &s->name); \
106 else if (nla) \
107 dprint_field(dir, nla_type, #name, \
108 (nla_type == NLA_FLAG) ? NULL \
109 : nla_data(nla)); \
110 } while (0)
111
112 #define DPRINT_ARRAY(dir, nla_type, name, s, nla) \
113 do { \
114 if (s) \
115 dprint_array(dir, nla_type, #name, \
116 s->name, s->name ## _len); \
117 else if (nla) \
118 dprint_array(dir, nla_type, #name, \
119 nla_data(nla), nla_len(nla)); \
120 } while (0)
121 #else
122 #define DPRINT_TLA(a, op, b) do {} while (0)
123 #define DPRINT_FIELD(dir, nla_type, name, s, nla) do {} while (0)
124 #define DPRINT_ARRAY(dir, nla_type, name, s, nla) do {} while (0)
125 #endif
126
127 /*
128 * Magic: provide conversion functions {{{1
129 * populate struct from attribute table:
130 * {{{2
131 */
132
133 /* processing of generic netlink messages is serialized.
134 * use one static buffer for parsing of nested attributes */
135 static struct nlattr *nested_attr_tb[128];
136
137 #undef GENL_struct
138 #define GENL_struct(tag_name, tag_number, s_name, s_fields) \
139 /* *_from_attrs functions are static, but potentially unused */ \
140 static int __ ## s_name ## _from_attrs(struct s_name *s, \
141 struct genl_info *info, bool exclude_invariants) \
142 { \
143 const int maxtype = ARRAY_SIZE(s_name ## _nl_policy)-1; \
144 struct nlattr *tla = info->attrs[tag_number]; \
145 struct nlattr **ntb = nested_attr_tb; \
146 struct nlattr *nla; \
147 int err; \
148 BUILD_BUG_ON(ARRAY_SIZE(s_name ## _nl_policy) > ARRAY_SIZE(nested_attr_tb)); \
149 if (!tla) \
150 return -ENOMSG; \
151 DPRINT_TLA(#s_name, "<=-", #tag_name); \
152 err = drbd_nla_parse_nested(ntb, maxtype, tla, s_name ## _nl_policy); \
153 if (err) \
154 return err; \
155 \
156 s_fields \
157 return 0; \
158 } __attribute__((unused)) \
159 static int s_name ## _from_attrs(struct s_name *s, \
160 struct genl_info *info) \
161 { \
162 return __ ## s_name ## _from_attrs(s, info, false); \
163 } __attribute__((unused)) \
164 static int s_name ## _from_attrs_for_change(struct s_name *s, \
165 struct genl_info *info) \
166 { \
167 return __ ## s_name ## _from_attrs(s, info, true); \
168 } __attribute__((unused)) \
169
170 #define __assign(attr_nr, attr_flag, name, nla_type, type, assignment...) \
171 nla = ntb[attr_nr]; \
172 if (nla) { \
173 if (exclude_invariants && !!((attr_flag) & DRBD_F_INVARIANT)) { \
174 pr_info("<< must not change invariant attr: %s\n", #name); \
175 return -EEXIST; \
176 } \
177 assignment; \
178 } else if (exclude_invariants && !!((attr_flag) & DRBD_F_INVARIANT)) { \
179 /* attribute missing from payload, */ \
180 /* which was expected */ \
181 } else if ((attr_flag) & DRBD_F_REQUIRED) { \
182 pr_info("<< missing attr: %s\n", #name); \
183 return -ENOMSG; \
184 }
185
186 #undef __field
187 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
188 __is_signed) \
189 __assign(attr_nr, attr_flag, name, nla_type, type, \
190 if (s) \
191 s->name = __get(nla); \
192 DPRINT_FIELD("<<", nla_type, name, s, nla))
193
194 /* validate_nla() already checked nla_len <= maxlen appropriately. */
195 #undef __array
196 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \
197 __get, __put, __is_signed) \
198 __assign(attr_nr, attr_flag, name, nla_type, type, \
199 if (s) \
200 s->name ## _len = \
201 __get(s->name, nla, maxlen); \
202 DPRINT_ARRAY("<<", nla_type, name, s, nla))
203
204 #include GENL_MAGIC_INCLUDE_FILE
205
206 #undef GENL_struct
207 #define GENL_struct(tag_name, tag_number, s_name, s_fields)
208
209 /*
210 * Magic: define op number to op name mapping {{{1
211 * {{{2
212 */
CONCATENATE(GENL_MAGIC_FAMILY,_genl_cmd_to_str)213 static const char *CONCATENATE(GENL_MAGIC_FAMILY, _genl_cmd_to_str)(__u8 cmd)
214 {
215 switch (cmd) {
216 #undef GENL_op
217 #define GENL_op(op_name, op_num, handler, tla_list) \
218 case op_num: return #op_name;
219 #include GENL_MAGIC_INCLUDE_FILE
220 default:
221 return "unknown";
222 }
223 }
224
225 #ifdef __KERNEL__
226 #include <linux/stringify.h>
227 /*
228 * Magic: define genl_ops {{{1
229 * {{{2
230 */
231
232 #undef GENL_op
233 #define GENL_op(op_name, op_num, handler, tla_list) \
234 { \
235 handler \
236 .cmd = op_name, \
237 },
238
239 #define ZZZ_genl_ops CONCATENATE(GENL_MAGIC_FAMILY, _genl_ops)
240 static struct genl_ops ZZZ_genl_ops[] __read_mostly = {
241 #include GENL_MAGIC_INCLUDE_FILE
242 };
243
244 #undef GENL_op
245 #define GENL_op(op_name, op_num, handler, tla_list)
246
247 /*
248 * Define the genl_family, multicast groups, {{{1
249 * and provide register/unregister functions.
250 * {{{2
251 */
252 #define ZZZ_genl_family CONCATENATE(GENL_MAGIC_FAMILY, _genl_family)
253 static struct genl_family ZZZ_genl_family;
254 /*
255 * Magic: define multicast groups
256 * Magic: define multicast group registration helper
257 */
258 #define ZZZ_genl_mcgrps CONCATENATE(GENL_MAGIC_FAMILY, _genl_mcgrps)
259 static const struct genl_multicast_group ZZZ_genl_mcgrps[] = {
260 #undef GENL_mc_group
261 #define GENL_mc_group(group) { .name = #group, },
262 #include GENL_MAGIC_INCLUDE_FILE
263 };
264
CONCATENATE(GENL_MAGIC_FAMILY,group_ids)265 enum CONCATENATE(GENL_MAGIC_FAMILY, group_ids) {
266 #undef GENL_mc_group
267 #define GENL_mc_group(group) CONCATENATE(GENL_MAGIC_FAMILY, _group_ ## group),
268 #include GENL_MAGIC_INCLUDE_FILE
269 };
270
271 #undef GENL_mc_group
272 #define GENL_mc_group(group) \
273 static int CONCATENATE(GENL_MAGIC_FAMILY, _genl_multicast_ ## group)( \
274 struct sk_buff *skb, gfp_t flags) \
275 { \
276 unsigned int group_id = \
277 CONCATENATE(GENL_MAGIC_FAMILY, _group_ ## group); \
278 return genlmsg_multicast(&ZZZ_genl_family, skb, 0, \
279 group_id, flags); \
280 }
281
282 #include GENL_MAGIC_INCLUDE_FILE
283
284 #undef GENL_mc_group
285 #define GENL_mc_group(group)
286
287 static struct genl_family ZZZ_genl_family __ro_after_init = {
288 .name = __stringify(GENL_MAGIC_FAMILY),
289 .version = GENL_MAGIC_VERSION,
290 #ifdef GENL_MAGIC_FAMILY_HDRSZ
291 .hdrsize = NLA_ALIGN(GENL_MAGIC_FAMILY_HDRSZ),
292 #endif
293 .maxattr = ARRAY_SIZE(CONCATENATE(GENL_MAGIC_FAMILY, _tla_nl_policy))-1,
294 .policy = CONCATENATE(GENL_MAGIC_FAMILY, _tla_nl_policy),
295 .ops = ZZZ_genl_ops,
296 .n_ops = ARRAY_SIZE(ZZZ_genl_ops),
297 .mcgrps = ZZZ_genl_mcgrps,
298 .resv_start_op = 42, /* drbd is currently the only user */
299 .n_mcgrps = ARRAY_SIZE(ZZZ_genl_mcgrps),
300 .module = THIS_MODULE,
301 };
302
CONCATENATE(GENL_MAGIC_FAMILY,_genl_register)303 int CONCATENATE(GENL_MAGIC_FAMILY, _genl_register)(void)
304 {
305 return genl_register_family(&ZZZ_genl_family);
306 }
307
CONCATENATE(GENL_MAGIC_FAMILY,_genl_unregister)308 void CONCATENATE(GENL_MAGIC_FAMILY, _genl_unregister)(void)
309 {
310 genl_unregister_family(&ZZZ_genl_family);
311 }
312
313 /*
314 * Magic: provide conversion functions {{{1
315 * populate skb from struct.
316 * {{{2
317 */
318
319 #undef GENL_op
320 #define GENL_op(op_name, op_num, handler, tla_list)
321
322 #undef GENL_struct
323 #define GENL_struct(tag_name, tag_number, s_name, s_fields) \
324 static int s_name ## _to_skb(struct sk_buff *skb, struct s_name *s, \
325 const bool exclude_sensitive) \
326 { \
327 struct nlattr *tla = nla_nest_start(skb, tag_number); \
328 if (!tla) \
329 goto nla_put_failure; \
330 DPRINT_TLA(#s_name, "-=>", #tag_name); \
331 s_fields \
332 nla_nest_end(skb, tla); \
333 return 0; \
334 \
335 nla_put_failure: \
336 if (tla) \
337 nla_nest_cancel(skb, tla); \
338 return -EMSGSIZE; \
339 } \
340 static inline int s_name ## _to_priv_skb(struct sk_buff *skb, \
341 struct s_name *s) \
342 { \
343 return s_name ## _to_skb(skb, s, 0); \
344 } \
345 static inline int s_name ## _to_unpriv_skb(struct sk_buff *skb, \
346 struct s_name *s) \
347 { \
348 return s_name ## _to_skb(skb, s, 1); \
349 }
350
351
352 #undef __field
353 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
354 __is_signed) \
355 if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) { \
356 DPRINT_FIELD(">>", nla_type, name, s, NULL); \
357 if (__put(skb, attr_nr, s->name)) \
358 goto nla_put_failure; \
359 }
360
361 #undef __array
362 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \
363 __get, __put, __is_signed) \
364 if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) { \
365 DPRINT_ARRAY(">>",nla_type, name, s, NULL); \
366 if (__put(skb, attr_nr, min_t(int, maxlen, \
367 s->name ## _len + (nla_type == NLA_NUL_STRING)),\
368 s->name)) \
369 goto nla_put_failure; \
370 }
371
372 #include GENL_MAGIC_INCLUDE_FILE
373
374
375 /* Functions for initializing structs to default values. */
376
377 #undef __field
378 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
379 __is_signed)
380 #undef __array
381 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \
382 __get, __put, __is_signed)
383 #undef __u32_field_def
384 #define __u32_field_def(attr_nr, attr_flag, name, default) \
385 x->name = default;
386 #undef __s32_field_def
387 #define __s32_field_def(attr_nr, attr_flag, name, default) \
388 x->name = default;
389 #undef __flg_field_def
390 #define __flg_field_def(attr_nr, attr_flag, name, default) \
391 x->name = default;
392 #undef __str_field_def
393 #define __str_field_def(attr_nr, attr_flag, name, maxlen) \
394 memset(x->name, 0, sizeof(x->name)); \
395 x->name ## _len = 0;
396 #undef GENL_struct
397 #define GENL_struct(tag_name, tag_number, s_name, s_fields) \
398 static void set_ ## s_name ## _defaults(struct s_name *x) __attribute__((unused)); \
399 static void set_ ## s_name ## _defaults(struct s_name *x) { \
400 s_fields \
401 }
402
403 #include GENL_MAGIC_INCLUDE_FILE
404
405 #endif /* __KERNEL__ */
406
407 /* }}}1 */
408 #endif /* GENL_MAGIC_FUNC_H */
409