include/linux/genl_magic_func.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef GENL_MAGIC_FUNC_H
   3 #define GENL_MAGIC_FUNC_H
   4
   5 #include <linux/genl_magic_struct.h>
   6
   7 /*
   8  * Magic: declare tla policy                                            {{{1
   9  * Magic: declare nested policies
  10  *                                                                      {{{2
  11  */
  12 #undef GENL_mc_group
  13 #define GENL_mc_group(group)
  14
  15 #undef GENL_notification
  16 #define GENL_notification(op_name, op_num, mcast_group, tla_list)
  17
  18 #undef GENL_op
  19 #define GENL_op(op_name, op_num, handler, tla_list)
  20
  21 #undef GENL_struct
  22 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
  23         [tag_name] = { .type = NLA_NESTED },
  24
  25 static struct nla_policy CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy)[] = {
  26 #include GENL_MAGIC_INCLUDE_FILE
  27 };
  28
  29 #undef GENL_struct
  30 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
  31 static struct nla_policy s_name ## _nl_policy[] __read_mostly =         \
  32 { s_fields };
  33
  34 #undef __field
  35 #define __field(attr_nr, attr_flag, name, nla_type, _type, __get,       \
  36                  __put, __is_signed)                                    \
  37         [attr_nr] = { .type = nla_type },
  38
  39 #undef __array
  40 #define __array(attr_nr, attr_flag, name, nla_type, _type, maxlen,      \
  41                 __get, __put, __is_signed)                              \
  42         [attr_nr] = { .type = nla_type,                                 \
  43                       .len = maxlen - (nla_type == NLA_NUL_STRING) },
  44
  45 #include GENL_MAGIC_INCLUDE_FILE
  46
  47 #ifndef __KERNEL__
  48 #ifndef pr_info
  49 #define pr_info(args...)        fprintf(stderr, args);
  50 #endif
  51 #endif
  52
  53 #ifdef GENL_MAGIC_DEBUG
  54 static void dprint_field(const char *dir, int nla_type,
  55                 const char *name, void *valp)
  56 {
  57         __u64 val = valp ? *(__u32 *)valp : 1;
  58         switch (nla_type) {
  59         case NLA_U8:  val = (__u8)val;
  60         case NLA_U16: val = (__u16)val;
  61         case NLA_U32: val = (__u32)val;
  62                 pr_info("%s attr %s: %d 0x%08x\n", dir,
  63                         name, (int)val, (unsigned)val);
  64                 break;
  65         case NLA_U64:
  66                 val = *(__u64*)valp;
  67                 pr_info("%s attr %s: %lld 0x%08llx\n", dir,
  68                         name, (long long)val, (unsigned long long)val);
  69                 break;
  70         case NLA_FLAG:
  71                 if (val)
  72                         pr_info("%s attr %s: set\n", dir, name);
  73                 break;
  74         }
  75 }
  76
  77 static void dprint_array(const char *dir, int nla_type,
  78                 const char *name, const char *val, unsigned len)
  79 {
  80         switch (nla_type) {
  81         case NLA_NUL_STRING:
  82                 if (len && val[len-1] == '\0')
  83                         len--;
  84                 pr_info("%s attr %s: [len:%u] '%s'\n", dir, name, len, val);
  85                 break;
  86         default:
  87                 /* we can always show 4 byte,
  88                  * thats what nlattr are aligned to. */
  89                 pr_info("%s attr %s: [len:%u] %02x%02x%02x%02x ...\n",
  90                         dir, name, len, val[0], val[1], val[2], val[3]);
  91         }
  92 }
  93
  94 #define DPRINT_TLA(a, op, b) pr_info("%s %s %s\n", a, op, b);
  95
  96 /* Name is a member field name of the struct s.
  97  * If s is NULL (only parsing, no copy requested in *_from_attrs()),
  98  * nla is supposed to point to the attribute containing the information
  99  * corresponding to that struct member. */
 100 #define DPRINT_FIELD(dir, nla_type, name, s, nla)                       \
 101         do {                                                            \
 102                 if (s)                                                  \
 103                         dprint_field(dir, nla_type, #name, &s->name);   \
 104                 else if (nla)                                           \
 105                         dprint_field(dir, nla_type, #name,              \
 106                                 (nla_type == NLA_FLAG) ? NULL           \
 107                                                 : nla_data(nla));       \
 108         } while (0)
 109
 110 #define DPRINT_ARRAY(dir, nla_type, name, s, nla)                       \
 111         do {                                                            \
 112                 if (s)                                                  \
 113                         dprint_array(dir, nla_type, #name,              \
 114                                         s->name, s->name ## _len);      \
 115                 else if (nla)                                           \
 116                         dprint_array(dir, nla_type, #name,              \
 117                                         nla_data(nla), nla_len(nla));   \
 118         } while (0)
 119 #else
 120 #define DPRINT_TLA(a, op, b) do {} while (0)
 121 #define DPRINT_FIELD(dir, nla_type, name, s, nla) do {} while (0)
 122 #define DPRINT_ARRAY(dir, nla_type, name, s, nla) do {} while (0)
 123 #endif
 124
 125 /*
 126  * Magic: provide conversion functions                                  {{{1
 127  * populate struct from attribute table:
 128  *                                                                      {{{2
 129  */
 130
 131 /* processing of generic netlink messages is serialized.
 132  * use one static buffer for parsing of nested attributes */
 133 static struct nlattr *nested_attr_tb[128];
 134
 135 #ifndef BUILD_BUG_ON
 136 /* Force a compilation error if condition is true */
 137 #define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition))
 138 /* Force a compilation error if condition is true, but also produce a
 139    result (of value 0 and type size_t), so the expression can be used
 140    e.g. in a structure initializer (or where-ever else comma expressions
 141    aren't permitted). */
 142 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 143 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 144 #endif
 145
 146 #undef GENL_struct
 147 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
 148 /* *_from_attrs functions are static, but potentially unused */         \
 149 static int __ ## s_name ## _from_attrs(struct s_name *s,                \
 150                 struct genl_info *info, bool exclude_invariants)        \
 151 {                                                                       \
 152         const int maxtype = ARRAY_SIZE(s_name ## _nl_policy)-1;         \
 153         struct nlattr *tla = info->attrs[tag_number];                   \
 154         struct nlattr **ntb = nested_attr_tb;                           \
 155         struct nlattr *nla;                                             \
 156         int err;                                                        \
 157         BUILD_BUG_ON(ARRAY_SIZE(s_name ## _nl_policy) > ARRAY_SIZE(nested_attr_tb));    \
 158         if (!tla)                                                       \
 159                 return -ENOMSG;                                         \
 160         DPRINT_TLA(#s_name, "<=-", #tag_name);                          \
 161         err = drbd_nla_parse_nested(ntb, maxtype, tla, s_name ## _nl_policy);   \
 162         if (err)                                                        \
 163                 return err;                                             \
 164                                                                         \
 165         s_fields                                                        \
 166         return 0;                                                       \
 167 }                                       __attribute__((unused))         \
 168 static int s_name ## _from_attrs(struct s_name *s,                      \
 169                                                 struct genl_info *info) \
 170 {                                                                       \
 171         return __ ## s_name ## _from_attrs(s, info, false);             \
 172 }                                       __attribute__((unused))         \
 173 static int s_name ## _from_attrs_for_change(struct s_name *s,           \
 174                                                 struct genl_info *info) \
 175 {                                                                       \
 176         return __ ## s_name ## _from_attrs(s, info, true);              \
 177 }                                       __attribute__((unused))         \
 178
 179 #define __assign(attr_nr, attr_flag, name, nla_type, type, assignment...)       \
 180                 nla = ntb[attr_nr];                                             \
 181                 if (nla) {                                              \
 182                         if (exclude_invariants && !!((attr_flag) & DRBD_F_INVARIANT)) {         \
 183                                 pr_info("<< must not change invariant attr: %s\n", #name);      \
 184                                 return -EEXIST;                         \
 185                         }                                               \
 186                         assignment;                                     \
 187                 } else if (exclude_invariants && !!((attr_flag) & DRBD_F_INVARIANT)) {          \
 188                         /* attribute missing from payload, */           \
 189                         /* which was expected */                        \
 190                 } else if ((attr_flag) & DRBD_F_REQUIRED) {             \
 191                         pr_info("<< missing attr: %s\n", #name);        \
 192                         return -ENOMSG;                                 \
 193                 }
 194
 195 #undef __field
 196 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
 197                 __is_signed)                                            \
 198         __assign(attr_nr, attr_flag, name, nla_type, type,              \
 199                         if (s)                                          \
 200                                 s->name = __get(nla);                   \
 201                         DPRINT_FIELD("<<", nla_type, name, s, nla))
 202
 203 /* validate_nla() already checked nla_len <= maxlen appropriately. */
 204 #undef __array
 205 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen,       \
 206                 __get, __put, __is_signed)                              \
 207         __assign(attr_nr, attr_flag, name, nla_type, type,              \
 208                         if (s)                                          \
 209                                 s->name ## _len =                       \
 210                                         __get(s->name, nla, maxlen);    \
 211                         DPRINT_ARRAY("<<", nla_type, name, s, nla))
 212
 213 #include GENL_MAGIC_INCLUDE_FILE
 214
 215 #undef GENL_struct
 216 #define GENL_struct(tag_name, tag_number, s_name, s_fields)
 217
 218 /*
 219  * Magic: define op number to op name mapping                           {{{1
 220  *                                                                      {{{2
 221  */
 222 const char *CONCAT_(GENL_MAGIC_FAMILY, _genl_cmd_to_str)(__u8 cmd)
 223 {
 224         switch (cmd) {
 225 #undef GENL_op
 226 #define GENL_op(op_name, op_num, handler, tla_list)             \
 227         case op_num: return #op_name;
 228 #include GENL_MAGIC_INCLUDE_FILE
 229         default:
 230                      return "unknown";
 231         }
 232 }
 233
 234 #ifdef __KERNEL__
 235 #include <linux/stringify.h>
 236 /*
 237  * Magic: define genl_ops                                               {{{1
 238  *                                                                      {{{2
 239  */
 240
 241 #undef GENL_op
 242 #define GENL_op(op_name, op_num, handler, tla_list)             \
 243 {                                                               \
 244         handler                                                 \
 245         .cmd = op_name,                                         \
 246         .policy = CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy),   \
 247 },
 248
 249 #define ZZZ_genl_ops            CONCAT_(GENL_MAGIC_FAMILY, _genl_ops)
 250 static struct genl_ops ZZZ_genl_ops[] __read_mostly = {
 251 #include GENL_MAGIC_INCLUDE_FILE
 252 };
 253
 254 #undef GENL_op
 255 #define GENL_op(op_name, op_num, handler, tla_list)
 256
 257 /*
 258  * Define the genl_family, multicast groups,                            {{{1
 259  * and provide register/unregister functions.
 260  *                                                                      {{{2
 261  */
 262 #define ZZZ_genl_family         CONCAT_(GENL_MAGIC_FAMILY, _genl_family)
 263 static struct genl_family ZZZ_genl_family;
 264 /*
 265  * Magic: define multicast groups
 266  * Magic: define multicast group registration helper
 267  */
 268 #define ZZZ_genl_mcgrps         CONCAT_(GENL_MAGIC_FAMILY, _genl_mcgrps)
 269 static const struct genl_multicast_group ZZZ_genl_mcgrps[] = {
 270 #undef GENL_mc_group
 271 #define GENL_mc_group(group) { .name = #group, },
 272 #include GENL_MAGIC_INCLUDE_FILE
 273 };
 274
 275 enum CONCAT_(GENL_MAGIC_FAMILY, group_ids) {
 276 #undef GENL_mc_group
 277 #define GENL_mc_group(group) CONCAT_(GENL_MAGIC_FAMILY, _group_ ## group),
 278 #include GENL_MAGIC_INCLUDE_FILE
 279 };
 280
 281 #undef GENL_mc_group
 282 #define GENL_mc_group(group)                                            \
 283 static int CONCAT_(GENL_MAGIC_FAMILY, _genl_multicast_ ## group)(       \
 284         struct sk_buff *skb, gfp_t flags)                               \
 285 {                                                                       \
 286         unsigned int group_id =                                         \
 287                 CONCAT_(GENL_MAGIC_FAMILY, _group_ ## group);           \
 288         return genlmsg_multicast(&ZZZ_genl_family, skb, 0,              \
 289                                  group_id, flags);                      \
 290 }
 291
 292 #include GENL_MAGIC_INCLUDE_FILE
 293
 294 #undef GENL_mc_group
 295 #define GENL_mc_group(group)
 296
 297 static struct genl_family ZZZ_genl_family __ro_after_init = {
 298         .name = __stringify(GENL_MAGIC_FAMILY),
 299         .version = GENL_MAGIC_VERSION,
 300 #ifdef GENL_MAGIC_FAMILY_HDRSZ
 301         .hdrsize = NLA_ALIGN(GENL_MAGIC_FAMILY_HDRSZ),
 302 #endif
 303         .maxattr = ARRAY_SIZE(drbd_tla_nl_policy)-1,
 304         .ops = ZZZ_genl_ops,
 305         .n_ops = ARRAY_SIZE(ZZZ_genl_ops),
 306         .mcgrps = ZZZ_genl_mcgrps,
 307         .n_mcgrps = ARRAY_SIZE(ZZZ_genl_mcgrps),
 308         .module = THIS_MODULE,
 309 };
 310
 311 int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void)
 312 {
 313         return genl_register_family(&ZZZ_genl_family);
 314 }
 315
 316 void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void)
 317 {
 318         genl_unregister_family(&ZZZ_genl_family);
 319 }
 320
 321 /*
 322  * Magic: provide conversion functions                                  {{{1
 323  * populate skb from struct.
 324  *                                                                      {{{2
 325  */
 326
 327 #undef GENL_op
 328 #define GENL_op(op_name, op_num, handler, tla_list)
 329
 330 #undef GENL_struct
 331 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
 332 static int s_name ## _to_skb(struct sk_buff *skb, struct s_name *s,     \
 333                 const bool exclude_sensitive)                           \
 334 {                                                                       \
 335         struct nlattr *tla = nla_nest_start(skb, tag_number);           \
 336         if (!tla)                                                       \
 337                 goto nla_put_failure;                                   \
 338         DPRINT_TLA(#s_name, "-=>", #tag_name);                          \
 339         s_fields                                                        \
 340         nla_nest_end(skb, tla);                                         \
 341         return 0;                                                       \
 342                                                                         \
 343 nla_put_failure:                                                        \
 344         if (tla)                                                        \
 345                 nla_nest_cancel(skb, tla);                              \
 346         return -EMSGSIZE;                                               \
 347 }                                                                       \
 348 static inline int s_name ## _to_priv_skb(struct sk_buff *skb,           \
 349                 struct s_name *s)                                       \
 350 {                                                                       \
 351         return s_name ## _to_skb(skb, s, 0);                            \
 352 }                                                                       \
 353 static inline int s_name ## _to_unpriv_skb(struct sk_buff *skb,         \
 354                 struct s_name *s)                                       \
 355 {                                                                       \
 356         return s_name ## _to_skb(skb, s, 1);                            \
 357 }
 358
 359
 360 #undef __field
 361 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
 362                 __is_signed)                                            \
 363         if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) {  \
 364                 DPRINT_FIELD(">>", nla_type, name, s, NULL);            \
 365                 if (__put(skb, attr_nr, s->name))                       \
 366                         goto nla_put_failure;                           \
 367         }
 368
 369 #undef __array
 370 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen,       \
 371                 __get, __put, __is_signed)                              \
 372         if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) {  \
 373                 DPRINT_ARRAY(">>",nla_type, name, s, NULL);             \
 374                 if (__put(skb, attr_nr, min_t(int, maxlen,              \
 375                         s->name ## _len + (nla_type == NLA_NUL_STRING)),\
 376                                                 s->name))               \
 377                         goto nla_put_failure;                           \
 378         }
 379
 380 #include GENL_MAGIC_INCLUDE_FILE
 381
 382
 383 /* Functions for initializing structs to default values.  */
 384
 385 #undef __field
 386 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
 387                 __is_signed)
 388 #undef __array
 389 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen,       \
 390                 __get, __put, __is_signed)
 391 #undef __u32_field_def
 392 #define __u32_field_def(attr_nr, attr_flag, name, default)              \
 393         x->name = default;
 394 #undef __s32_field_def
 395 #define __s32_field_def(attr_nr, attr_flag, name, default)              \
 396         x->name = default;
 397 #undef __flg_field_def
 398 #define __flg_field_def(attr_nr, attr_flag, name, default)              \
 399         x->name = default;
 400 #undef __str_field_def
 401 #define __str_field_def(attr_nr, attr_flag, name, maxlen)               \
 402         memset(x->name, 0, sizeof(x->name));                            \
 403         x->name ## _len = 0;
 404 #undef GENL_struct
 405 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
 406 static void set_ ## s_name ## _defaults(struct s_name *x) __attribute__((unused)); \
 407 static void set_ ## s_name ## _defaults(struct s_name *x) {     \
 408 s_fields                                                                \
 409 }
 410
 411 #include GENL_MAGIC_INCLUDE_FILE
 412
 413 #endif /* __KERNEL__ */
 414
 415 /* }}}1 */
 416 #endif /* GENL_MAGIC_FUNC_H */
 417 /* vim: set foldmethod=marker foldlevel=1 nofoldenable : */