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 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 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 */ 212 static 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 }; 263 264 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 }; 301 302 int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void) 303 { 304 return genl_register_family(&ZZZ_genl_family); 305 } 306 307 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