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 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 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 */ 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 }; 264 265 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 }; 302 303 int CONCATENATE(GENL_MAGIC_FAMILY, _genl_register)(void) 304 { 305 return genl_register_family(&ZZZ_genl_family); 306 } 307 308 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