genl_magic_func.h (11809B)
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 26static 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) \ 32static 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 55static 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 78static 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 */ 134static 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 */ \ 139static 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)) \ 158static 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)) \ 163static 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 */ 212const 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) 239static 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) 252static 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) 258static 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 264enum 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) \ 272static 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 286static 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 .n_mcgrps = ARRAY_SIZE(ZZZ_genl_mcgrps), 298 .module = THIS_MODULE, 299}; 300 301int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void) 302{ 303 return genl_register_family(&ZZZ_genl_family); 304} 305 306void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void) 307{ 308 genl_unregister_family(&ZZZ_genl_family); 309} 310 311/* 312 * Magic: provide conversion functions {{{1 313 * populate skb from struct. 314 * {{{2 315 */ 316 317#undef GENL_op 318#define GENL_op(op_name, op_num, handler, tla_list) 319 320#undef GENL_struct 321#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ 322static int s_name ## _to_skb(struct sk_buff *skb, struct s_name *s, \ 323 const bool exclude_sensitive) \ 324{ \ 325 struct nlattr *tla = nla_nest_start(skb, tag_number); \ 326 if (!tla) \ 327 goto nla_put_failure; \ 328 DPRINT_TLA(#s_name, "-=>", #tag_name); \ 329 s_fields \ 330 nla_nest_end(skb, tla); \ 331 return 0; \ 332 \ 333nla_put_failure: \ 334 if (tla) \ 335 nla_nest_cancel(skb, tla); \ 336 return -EMSGSIZE; \ 337} \ 338static inline int s_name ## _to_priv_skb(struct sk_buff *skb, \ 339 struct s_name *s) \ 340{ \ 341 return s_name ## _to_skb(skb, s, 0); \ 342} \ 343static inline int s_name ## _to_unpriv_skb(struct sk_buff *skb, \ 344 struct s_name *s) \ 345{ \ 346 return s_name ## _to_skb(skb, s, 1); \ 347} 348 349 350#undef __field 351#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \ 352 __is_signed) \ 353 if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) { \ 354 DPRINT_FIELD(">>", nla_type, name, s, NULL); \ 355 if (__put(skb, attr_nr, s->name)) \ 356 goto nla_put_failure; \ 357 } 358 359#undef __array 360#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \ 361 __get, __put, __is_signed) \ 362 if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) { \ 363 DPRINT_ARRAY(">>",nla_type, name, s, NULL); \ 364 if (__put(skb, attr_nr, min_t(int, maxlen, \ 365 s->name ## _len + (nla_type == NLA_NUL_STRING)),\ 366 s->name)) \ 367 goto nla_put_failure; \ 368 } 369 370#include GENL_MAGIC_INCLUDE_FILE 371 372 373/* Functions for initializing structs to default values. */ 374 375#undef __field 376#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \ 377 __is_signed) 378#undef __array 379#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, \ 380 __get, __put, __is_signed) 381#undef __u32_field_def 382#define __u32_field_def(attr_nr, attr_flag, name, default) \ 383 x->name = default; 384#undef __s32_field_def 385#define __s32_field_def(attr_nr, attr_flag, name, default) \ 386 x->name = default; 387#undef __flg_field_def 388#define __flg_field_def(attr_nr, attr_flag, name, default) \ 389 x->name = default; 390#undef __str_field_def 391#define __str_field_def(attr_nr, attr_flag, name, maxlen) \ 392 memset(x->name, 0, sizeof(x->name)); \ 393 x->name ## _len = 0; 394#undef GENL_struct 395#define GENL_struct(tag_name, tag_number, s_name, s_fields) \ 396static void set_ ## s_name ## _defaults(struct s_name *x) __attribute__((unused)); \ 397static void set_ ## s_name ## _defaults(struct s_name *x) { \ 398s_fields \ 399} 400 401#include GENL_MAGIC_INCLUDE_FILE 402 403#endif /* __KERNEL__ */ 404 405/* }}}1 */ 406#endif /* GENL_MAGIC_FUNC_H */