include/linux/genl_magic_func.h

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