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 __read_mostly = {
 263         .id = GENL_ID_GENERATE,
 264         .name = __stringify(GENL_MAGIC_FAMILY),
 265         .version = GENL_MAGIC_VERSION,
 266 #ifdef GENL_MAGIC_FAMILY_HDRSZ
 267         .hdrsize = NLA_ALIGN(GENL_MAGIC_FAMILY_HDRSZ),
 268 #endif
 269         .maxattr = ARRAY_SIZE(drbd_tla_nl_policy)-1,
 270 };
 271
 272 /*
 273  * Magic: define multicast groups
 274  * Magic: define multicast group registration helper
 275  */
 276 #undef GENL_mc_group
 277 #define GENL_mc_group(group)                                            \
 278 static struct genl_multicast_group                                      \
 279 CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group) __read_mostly = {            \
 280         .name = #group,                                                 \
 281 };                                                                      \
 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, _mcg_ ## group).id;  \
 287         if (!group_id)                                                  \
 288                 return -EINVAL;                                         \
 289         return genlmsg_multicast(skb, 0, group_id, flags);              \
 290 }
 291
 292 #include GENL_MAGIC_INCLUDE_FILE
 293
 294 int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void)
 295 {
 296         int err = genl_register_family_with_ops(&ZZZ_genl_family,
 297                 ZZZ_genl_ops, ARRAY_SIZE(ZZZ_genl_ops));
 298         if (err)
 299                 return err;
 300 #undef GENL_mc_group
 301 #define GENL_mc_group(group)                                            \
 302         err = genl_register_mc_group(&ZZZ_genl_family,                  \
 303                 &CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group));           \
 304         if (err)                                                        \
 305                 goto fail;                                              \
 306         else                                                            \
 307                 pr_info("%s: mcg %s: %u\n", #group,                     \
 308                         __stringify(GENL_MAGIC_FAMILY),                 \
 309                         CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group).id);
 310
 311 #include GENL_MAGIC_INCLUDE_FILE
 312
 313 #undef GENL_mc_group
 314 #define GENL_mc_group(group)
 315         return 0;
 316 fail:
 317         genl_unregister_family(&ZZZ_genl_family);
 318         return err;
 319 }
 320
 321 void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void)
 322 {
 323         genl_unregister_family(&ZZZ_genl_family);
 324 }
 325
 326 /*
 327  * Magic: provide conversion functions                                  {{{1
 328  * populate skb from struct.
 329  *                                                                      {{{2
 330  */
 331
 332 #undef GENL_op
 333 #define GENL_op(op_name, op_num, handler, tla_list)
 334
 335 #undef GENL_struct
 336 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
 337 static int s_name ## _to_skb(struct sk_buff *skb, struct s_name *s,     \
 338                 const bool exclude_sensitive)                           \
 339 {                                                                       \
 340         struct nlattr *tla = nla_nest_start(skb, tag_number);           \
 341         if (!tla)                                                       \
 342                 goto nla_put_failure;                                   \
 343         DPRINT_TLA(#s_name, "-=>", #tag_name);                          \
 344         s_fields                                                        \
 345         nla_nest_end(skb, tla);                                         \
 346         return 0;                                                       \
 347                                                                         \
 348 nla_put_failure:                                                        \
 349         if (tla)                                                        \
 350                 nla_nest_cancel(skb, tla);                              \
 351         return -EMSGSIZE;                                               \
 352 }                                                                       \
 353 static inline int s_name ## _to_priv_skb(struct sk_buff *skb,           \
 354                 struct s_name *s)                                       \
 355 {                                                                       \
 356         return s_name ## _to_skb(skb, s, 0);                            \
 357 }                                                                       \
 358 static inline int s_name ## _to_unpriv_skb(struct sk_buff *skb,         \
 359                 struct s_name *s)                                       \
 360 {                                                                       \
 361         return s_name ## _to_skb(skb, s, 1);                            \
 362 }
 363
 364
 365 #undef __field
 366 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
 367                 __is_signed)                                            \
 368         if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) {  \
 369                 DPRINT_FIELD(">>", nla_type, name, s, NULL);            \
 370                 if (__put(skb, attr_nr, s->name))                       \
 371                         goto nla_put_failure;                           \
 372         }
 373
 374 #undef __array
 375 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen,       \
 376                 __get, __put, __is_signed)                              \
 377         if (!exclude_sensitive || !((attr_flag) & DRBD_F_SENSITIVE)) {  \
 378                 DPRINT_ARRAY(">>",nla_type, name, s, NULL);             \
 379                 if (__put(skb, attr_nr, min_t(int, maxlen,              \
 380                         s->name ## _len + (nla_type == NLA_NUL_STRING)),\
 381                                                 s->name))               \
 382                         goto nla_put_failure;                           \
 383         }
 384
 385 #include GENL_MAGIC_INCLUDE_FILE
 386
 387
 388 /* Functions for initializing structs to default values.  */
 389
 390 #undef __field
 391 #define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put, \
 392                 __is_signed)
 393 #undef __array
 394 #define __array(attr_nr, attr_flag, name, nla_type, type, maxlen,       \
 395                 __get, __put, __is_signed)
 396 #undef __u32_field_def
 397 #define __u32_field_def(attr_nr, attr_flag, name, default)              \
 398         x->name = default;
 399 #undef __s32_field_def
 400 #define __s32_field_def(attr_nr, attr_flag, name, default)              \
 401         x->name = default;
 402 #undef __flg_field_def
 403 #define __flg_field_def(attr_nr, attr_flag, name, default)              \
 404         x->name = default;
 405 #undef __str_field_def
 406 #define __str_field_def(attr_nr, attr_flag, name, maxlen)               \
 407         memset(x->name, 0, sizeof(x->name));                            \
 408         x->name ## _len = 0;
 409 #undef GENL_struct
 410 #define GENL_struct(tag_name, tag_number, s_name, s_fields)             \
 411 static void set_ ## s_name ## _defaults(struct s_name *x) __attribute__((unused)); \
 412 static void set_ ## s_name ## _defaults(struct s_name *x) {     \
 413 s_fields                                                                \
 414 }
 415
 416 #include GENL_MAGIC_INCLUDE_FILE
 417
 418 #endif /* __KERNEL__ */
 419
 420 /* }}}1 */
 421 #endif /* GENL_MAGIC_FUNC_H */
 422 /* vim: set foldmethod=marker foldlevel=1 nofoldenable : */