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