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/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 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         .policy = CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy),   \
 237 },
 238
 239 #define ZZZ_genl_ops            CONCAT_(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         CONCAT_(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         CONCAT_(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 CONCAT_(GENL_MAGIC_FAMILY, group_ids) {
 266 #undef GENL_mc_group
 267 #define GENL_mc_group(group) CONCAT_(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 CONCAT_(GENL_MAGIC_FAMILY, _genl_multicast_ ## group)(       \
 274         struct sk_buff *skb, gfp_t flags)                               \
 275 {                                                                       \
 276         unsigned int group_id =                                         \
 277                 CONCAT_(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(drbd_tla_nl_policy)-1,
 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
 301 int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void)
 302 {
 303         return genl_register_family(&ZZZ_genl_family);
 304 }
 305
 306 void 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)             \
 322 static 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                                                                         \
 333 nla_put_failure:                                                        \
 334         if (tla)                                                        \
 335                 nla_nest_cancel(skb, tla);                              \
 336         return -EMSGSIZE;                                               \
 337 }                                                                       \
 338 static 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 }                                                                       \
 343 static 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)             \
 396 static void set_ ## s_name ## _defaults(struct s_name *x) __attribute__((unused)); \
 397 static void set_ ## s_name ## _defaults(struct s_name *x) {     \
 398 s_fields                                                                \
 399 }
 400
 401 #include GENL_MAGIC_INCLUDE_FILE
 402
 403 #endif /* __KERNEL__ */
 404
 405 /* }}}1 */
 406 #endif /* GENL_MAGIC_FUNC_H */
 407 /* vim: set foldmethod=marker foldlevel=1 nofoldenable : */